Quenching upon aggregation: 11‐Mercaptoundecanoic acid (11‐MUA)‐protected Au nanoparticles (11‐MUA‐AuNPs) are much more stable and fluoresce much more strongly than the corresponding unmodified ...AuNPs. After addition of 2,6‐pyridinedicarboxylic acid, the 11‐MUA‐AuNPs bind to HgII with both high sensitivity and selectivity.
This review provides a comprehensive overview of the growth methodologies and neutron shielding applications of Boron Nitride Nanotubes (BNNTs). BNNTs have garnered significant attention because of ...their unique combination of high thermal stability, mechanical strength, and exceptional neutron absorption properties. Synthesis methods for BNNTs, including laser ablation, thermal plasma treatment, chemical vapour deposition (CVD), and ball milling have been thoroughly examined, highlighting their mechanisms, advantages, and challenges. Each method contributes uniquely to the quality and applicability of BNNTs in terms of scalability and production efficiency. This study focused on the applications of BNNTs in neutron absorption, particularly in aerospace engineering. BNNTs have shown promising potential in enhancing the safety and longevity of space missions by providing effective radiation protection. Furthermore, their potential in medical applications, particularly in Boron Neutron Capture Therapy (BNCT) for cancer treatment, has been explored. BNCT offers a targeted approach to cancer therapy by utilizing the high boron-10 content of BNNTs for precise and localized treatment. This review also provides an outlook on the future of BNNT research, emphasizing the need for more efficient growth methods to facilitate wider adoption and commercialization. The versatility of BNNTs across various fields, from space exploration to medical science, underscores their potential as materials of significant scientific and technological importance. As research progresses, BNNTs are expected to play a pivotal role in advancing materials science and offer innovative solutions to complex challenges.
This review covers growth methodologies of boron nitride nanotubes (BNNTs) with various synthesis methods and highlights their neutron shielding applications in aerospace engineering and boron neutron capture therapy (BNCT).
Wearable strain sensors are widely researched as core components in electronic skin. However, their limited capability of detecting only a single axial strain, and their low sensitivity, stability, ...opacity, and high production costs hinder their use in advanced applications. Herein, multiaxially highly sensitive, optically transparent, chemically stable, and solution‐processed strain sensors are demonstrated. Transparent indium tin oxide and zinc oxide nanocrystals serve as metallic and insulating components in a metal–insulator matrix and as active materials for strain gauges. Synergetic sensitivity‐ and stability‐reinforcing agents are developed using a transparent SU‐8 polymer to enhance the sensitivity and encapsulate the devices, elevating the gauge factor up to over 3000 by blocking the reconnection of cracks caused by the Poisson effect. Cross‐shaped patterns with an orthogonal crack strategy are developed to detect a complex multiaxial strain, efficiently distinguishing strains applied in various directions with high sensitivity and selectivity. Finally, all‐transparent wearable strain sensors with Ag nanowire electrodes are fabricated using an all‐solution process, which effectively measure not only the human motion or emotion, but also the multiaxial strains occurring during human motion in real time. The strategies can provide a pathway to realize cost‐effective and high‐performance wearable sensors for advanced applications such as bio‐integrated devices.
Multiaxially highly sensitive, optically transparent, and chemically stable strain sensors are fabricated through an all‐solution process by developing a sensitivity‐ and stability‐reinforcing agent of SU‐8 polymer and orthogonally cracked hetero‐nanocrystal solids. The sensors with a high gauge factor over 3000 successfully detect various human signals such as the pulse, the vocal movement, facial expressions, and the wrist movement.
Natural graphite is labelled as a supply risk material due to rapidly increasing demand and limited reserves. The conventional method for the production of synthetic graphite has relied on the ...thermal heating at an extremely high temperature, 3000 °C, and long processing time, typically 2 weeks. Here, we report a novel and efficient method of graphitization using microwave heating with metal catalysts. The amorphous carbon powders turned into crystalline graphite in 5 minutes. Ideas for the scale-up of this work were proposed. In addition, numerical analysis revealed that the Maxwell–Wagner–Sillars polarization is inadequate for the mechanism underlying the microwave heating of solid carbon materials.
Hierarchical structures were fabricated on the surfaces of SUS304 plates using a one-step process of direct microwave irradiation under a carbon dioxide atmosphere. The surface nanostructures were ...composed of chrome-doped hematite single crystals. Superhydrophobic surfaces with a water contact angle up to 169° were obtained by chemical modification of the hierarchical structures. The samples maintained superhydrophobicity under NaCl solution up to 2 weeks.
Morphology-controlled growth of ZnO nano- and microstructures was achieved by microwave irradiation. Various basic ZnO structures, including nanorods, nanocandles, nanoneedles, nanodisks, nanonuts, ...microstars, microUFOs, and microballs were simply synthesized at a low temperature (90 °C) with low power microwave-assisted heating (about 50 W) and a subsequent aging process. These results could be obtained by changing the precursor chemicals, the capping agents, and the aging times. Even more complex ZnO structures, including ZnO bulky stars, cakes, and jellyfishes, were constructed by microwave irradiation to a mixture of the as-prepared basic ZnO structures and the solution I, IV, or V. This is a fast, simple, and reproducible method which does not require any template, catalyst, or surfactant but can control the morphology of ZnO crystals from simple to complex. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) were used to observe the morphology, crystallinity, and chemical composition of the ZnO structures. Growth mechanisms for shape-selective ZnO synthesis were proposed based on these results.
Mixed metal oxide (MMO) nanostructures co‐doped uniformly by carbon and nitrogen are synthesized for the first time by annealing a terephthalate‐intercalated layered double hydroxide (LDH) under ...ammonia gas flow. The interlayer gallery of LDH allows effective access of NH3 and the carbon source to its crystal lattice for a uniform nitrogen and carbon doping. Such co‐doped MMO exhibit significantly red‐shifted absorption spectra to visible light region relative to pure MMO. Photoelectrochemical water oxidation and incident‐photon‐to‐current‐conversion efficiency of LDH‐derived photocatalysts demonstrate that all the visible light absorption caused by the anion doping contributes to the photocatalytic activity over the entire absorbed wavelength range of <610 nm. Density functional theory calculations of electronic structures are performed to elucidate the possibility of bandgap narrowing upon nitrogen and carbon co‐doping on MMO structures.
The interlayer gallery of layered double hydroxides allows effective access of anion precursors to their crystal lattice for uniform carbon and nitrogen doping, which yields anion‐doped mixed metal oxide nanostructures with an excellent visible light photocatalytic activity. The visible light absorption caused by the anion doping contributes to the photocatalytic activity.
Natural gas hydrates are solid hydrogen-bonded water crystals containing small molecular gases. The amount of natural gas stored as hydrates in permafrost and ocean sediments is twice that of all ...other fossil fuels combined. However, hydrate blockages also hinder oil/gas pipeline transportation, and, despite their huge potential as energy sources, our insufficient understanding of hydrates has limited their extraction. Here, we report how the presence of amino acids in water induces changes in its structure and thus interrupts the formation of methane and natural gas hydrates. The perturbation of the structure of water by amino acids and the resulting selective inhibition of hydrate cage formation were observed directly. A strong correlation was found between the inhibition efficiencies of amino acids and their physicochemical properties, which demonstrates the importance of their direct interactions with water and the resulting dissolution environment. The inhibition of methane and natural gas hydrate formation by amino acids has the potential to be highly beneficial in practical applications such as hydrate exploitation, oil/gas transportation, and flow assurance. Further, the interactions between amino acids and water are essential to the equilibria and dynamics of many physical, chemical, biological, and environmental processes.
Natural gas hydrates are icy crystalline materials that contain hydrocarbons, which are the primary energy source for this civilization. The abundance of naturally occurring gas hydrates leads to a ...growing interest in exploitation. Despite their potential as energy resources and in industrial applications, there is insufficient understanding of hydrate kinetics, which hinders the utilization of these invaluable resources. Perturbation of liquid water structure by solutes has been proposed to be a key process in hydrate inhibition, but this hypothesis remains unproven. Here, we report the direct observation of the perturbation of the liquid water structure induced by amino acids using polarized Raman spectroscopy, and its influence on gas hydrate nucleation and growth kinetics. Amino acids with hydrophilic and/or electrically charged side chains disrupted the water structure and thus provided effective hydrate inhibition. The strong correlation between the extent of perturbation by amino acids and their inhibition performance constitutes convincing evidence for the perturbation inhibition mechanism. The present findings bring the practical applications of gas hydrates significantly closer, and provide a new perspective on the freezing and melting phenomena of naturally occurring gas hydrates.
•Optimization and modeling of the biofuel supply chain network was performed.•An integrated design of feedstock supply and biofuel production system is considered.•We examine changes in the effect of ...valuable parameter about biofuel infrastructure.•Algae generation biofuels have a cost of $5.91/gal ($1.56/l) considered in this study.
Many studies have developed mathematical programming models for optimal design of supply chains for agricultural or lingocellulosic biomass-derived bioethanol production. However, because of the shortcomings of using agricultural (food supply problems) and lingo-cellulosic biomass (low biomass availability and processing yield) as feedstock, use of micro-algal biomass has been considered for use as a feedstock for biodiesel (biofuel). Thus, in this study we developed a deterministic mathematical programming model for strategic planning design of a microalgae biomass-to-biodiesel supply chain network (MBBSCN) from feedstock fields to end users that simultaneously satisfies resource constraints, demand constraints, and technology over a long-term planning horizon.
The proposed deterministic model can help to determine where and how much feedstock to be transported, and where and how many refineries to be constructed to minimize the expected total cost including the co-product (naphtha and power) benefit. To demonstrate the feasibility of the proposed model, we conducted a case study based on the Korea biodiesel market data. In this case study, the optimized (i.e., most cost-effective) supply chain design can be gained at a reliable cost of ∼$US5.91/gal ($US1.56/l). In particular, this study can help to identify the technological bottlenecks and major cost drivers for the microalgae-to-diesel strategy, and can be also a guideline for development of various mathematical programming models for optimal design of microalgae biomass-derived biofuel supply chain like lingo-cellulosic biomass-based optimization studies.
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