From enfant terrible to problem-solver? Tracing the competing discourse to explain blockchain-related technological diffusion

Since the inception of blockchain-related technologies over a decade ago, investors’ uptake of the technologies has grown rapidly. But even with the advancement in standing from conceptual beginnings to real-world experimentation, mainstream adoption of the technologies in either organizational or individual contexts has yet to eventuate. To resolve this paradox, we examine progression of the technologies’ diffusion instead, and in the process, seek to uncover the underlying dynamics of sentiments at play. Diffusion involves multiple actions by different parties, with social discourses via diverse media playing an essential role. In demonstrating the interplay of support to resistance via media framing and the diffusion of innovation theory, findings from our paper contribute to the technology adoption literature. Understanding resistant behavior toward a new technology area could help resolve potential issues that may arise. This would hopefully lead to better technological implementation outcomes in future.     

Cyclic thermal shock resistance of h-BN composite ceramics with La2O3–Al2O3–SiO2 addition

The effects of La₂O₃–Al₂O₃–SiO₂ addition on the thermal conductivity, coefficient of thermal expansion (CTE), Young's modulus and cyclic thermal shock resistance of hot-pressed h-BN composite ceramics were investigated. The samples were heated to 1000 °C and then quenched to room temperature with 1–50 cycles, and the residual flexural strength was used to evaluate cyclic thermal shock resistance. h-BN composite ceramics containing 10 vol% La₂O₃–Al₂O₃ and 20 vol% SiO₂ addition exhibited the highest flexural strength, thermal conductivity and relatively low CTE, which were beneficial to the excellent thermal shock resistance. In addition, the viscous amorphous phase of ternary La₂O₃–Al₂O₃–SiO₂ system could accommodate and relax thermal stress contributing to the high thermal shock resistance. Therefore, the residual flexural strength still maintained the value of 234.3 MPa (86.9% of initial strength) after 50 cycles of thermal shock.     

One-step preparation of the superhydrophobic Al alloy surface with enhanced corrosion and wear resistance

Corrosion and wear failures are bottlenecks for restricting applications and developments of Al-based functional materials. As a new lubrication technology, superhydrophobic preparation provides an effective way to settle Al alloy corrosion. The preparation methods of superhydrophobic Al alloys are mainly multistep strategies. In this study, superhydrophobic Al alloy, has been prepared by an efficient one-step electrochemical etching process. Meanwhile, its micromorphology has been observed by a scanning electron microscope. The wettability has been measured by video optical contact angle meter. The corrosion behavior has been tested by electrochemical workstation, and wear performance has been characterized by friction tester. The results show that the micro-nanoterraced concave–convex structure has been fabricated and an as-prepared surface exhibits excellent superhydrophobic behavior. Further electrochemical and tribological tests show that corrosion resistance and wear resistance have also been significantly improved. This study provides a new method to prepare wear-resistant and corrosion-resistant Al alloy for widening applications of multifunctional Al-based engineering materials.     

Peptide-Mimicking Poly(2-oxazoline)s Displaying Potent Antimicrobial Properties

Poly(2-oxazoline)s have excellent biocompatibility and have been used as FDA-approved indirect food additives. The inert property of the hydrophilic poly(2-oxazoline)s suggests them as promising substitutes for poly(ethylene glycol) (PEG) in various applications such as anti-biofouling agents. It was recently reported that poly(2-oxazoline)s themselves have antimicrobial properties as synthetic mimics of host defense peptides. These studies revealed the bioactive properties of poly(2-oxazoline)s as a new class of functional peptide mimics, by mimicking host defense peptides to display potent and selective antimicrobial activities against methicillin-resistant Staphylococcus aureus both in vitro and in vivo, without concerns about antimicrobial resistance. The high structural diversity, facile synthesis, and potent and tunable antimicrobial properties underscore the great potential of poly(2-oxazoline)s as a class of novel antimicrobial agents in dealing with drug-resistant microbial infections and antimicrobial resistance.     

Achieving thermally stable and anti-hydrolytic Sr2Si5N8:Eu2+ phosphor via a nanoscale carbon deposition strategy

Chemical stability of phosphors is critical to the efficiency and lifetime of the white light-emitting diodes. Therefore, many strategies have been adopted to improve the stability of phosphors. However, it is still lack of report on the improvement of thermal stability and hydrolysis resistance of phosphors by a single layer coating. Due to the high transmittance and high chemical inertness of graphene, it was coated on the surface of Sr₂Si₅N₈:Eu²⁺ phosphor by chemical vapor deposition, aiming to improve its thermal stability and hydrolysis resistance. The chemical composition and microstructure of the coating were characterized and analyzed. A nanoscale carbon layer was attached on the surface of Sr₂Si₅N₈:Eu²⁺ phosphor particles in an amorphous state. In coated Sr₂Si₅N₈:Eu²⁺ phosphor, the oxidation degree of Eu²⁺ to Eu³⁺ was significantly suppressed. At the same time, the surface of Sr₂Si₅N₈:Eu²⁺ particle turned from hydrophilic to hydrophobic after carbon coating, and consequently the hydrolysis resistance of Sr₂Si₅N₈:Eu²⁺ phosphor was greatly improved. After tests at 85 °C and 85% humidity for 200 h, the carbon coated Sr₂Si₅N₈:Eu²⁺ phosphor still maintained about 95% of its initial luminous intensity as compared with 35% of the uncoated. By observing the in-situ microstructure evolution of coated phosphor in air-water vapor environment, remained presence of the carbon layer even at 500 °C explained the excellent chemical stability of carbon coated Sr₂Si₅N₈:Eu²⁺ phosphor in complex environment. These results indicate that a nanoscale carbon layer can be used to provide superior thermal stability and hydrolysis resistance of (oxy) nitrides phosphors.     

An automated treatment planning strategy for highly noncoplanar radiotherapy arc trajectories

Radiation therapy is a technology-driven cancer treatment modality that has experienced significant advances over the last decades, due to multidisciplinary contributions that include engineering and computing. Recent technological developments allow the use of noncoplanar volumetric modulated arc therapy (VMAT), one of the most recent photon treatment techniques, in clinical practice. In this work, an automated noncoplanar arc trajectory optimization framework designed in two modular phases is presented. First, a noncoplanar beam angle optimization algorithm is used to obtain a set of noncoplanar irradiation directions. Then, anchored in these directions, an optimization strategy is proposed to compute an optimal arc trajectory. The computational experiments considered a pool of twelve difficult head-and-neck tumor cases. It was possible to observe that, for some of these cases, the optimized noncoplanar arc trajectories led to significant treatment planning quality improvements, when compared with coplanar VMAT treatment plans. Although these experiments were done in a research environment treatment planning software (matRad), the conclusions can be of interest for a clinical setting: automated procedures can simplify the current treatment workflow, produce high-quality treatment plans, making better use of human resources and allowing for unbiased comparisons between different treatment techniques.     

Mechanical properties and wear behavior of Al5083 matrix composites reinforced with high amounts of SiC particles fabricated by combined stir casting and squeeze casting; A comparative study

Combined stir casting and squeeze casting processes were used to fabricate Al5083 matrix composites reinforced with 20, 25, and 30 wt% SiC_p. The microstructure, mechanical properties and wear behavior of the composites fabricated by combined stir casting and squeeze casting were compared with those fabricated by stir casting. The results revealed that the combined casting method improved the distribution of SiC particles through the reduction of the agglomeration of SiC particle and reduced the porosities of the samples from 2.32% to 1.29% in the sample containing 30 wt% SiC. These modifications led to the enhancement of mechanical properties i.e. increased the hardness to 85 BHN and the compressive strength to 350 MPa for the sample containing 30 wt% SiC fabricated by the combined casting method. In addition, the wear resistance of the samples fabricated by the combined casting method improved because of the reduced size of the wear debris as well as the smaller worn region. The dominant wear mechanism of all the composite samples fabricated by both methods was the delamination of the tribological layer while adhesion wear was dominant in the monolithic Al alloy.     

Ultra-high temperature ceramics based on ZrB2 obtained by pressureless sintering with addition of Cr3C2, Mo2C,and WC

ZrB₂-MeC and ZrB₂-19 vol% SiC-Me_xC_y where Me=Cr, Mo, W were obtained by pressureless sintering. The capability to promote densification of ZrB₂ and ZrB₂-SiC matrices is the highest for WC and lowest for Cr₃C₂. The interaction between the components results in the formation of new phases, such as MeB (MoB, CrB, WB), a solid solution based on ZrC, and a solid solution based on ZrB₂. The addition of Cr₃C₂ decreases the mechanical properties. On the other hand, the addition of Mo₂C or WC to ZrB₂-19 vol% SiC composite ceramics leads increased mechanical properties. Long-term oxidation of ceramics at 1500 °C for 50 h showed that, in binary ZrB₂-Me_xC_y, a protective oxide scale does not form on the surface thus leading to the destruction of the composite. On the contrary, triple composites showed high oxidation resistance, due to the formation of dense oxide scale on the surface, with ZrB₂-SiC-Mo₂C displaying the best performance.