Transport properties of fluids in nanopores are of both fundamental as well as practical interest. Water flow in carbon nanotubes (CNTs) has received significant attention since the early 2000s for technological applications of CNTs. In this article, we provide a brief overview of modeling the slip and flow enhancement of water in CNTs. A number of experimental and computational studies have found water to flow very fast in CNTs, but the measured flow rates, which are high compared to classical hydrodynamics predictions, are scattered over 2–5 orders of magnitude. Slip lengths of 1 to 500,000 nm, resulting in almost zero to 500,000 flow enhancement, are reported for water in CNTs with diameters of 0.8 to 10 nm. We highlight some challenges in modeling fluid flow in nanopores and outline a few research directions that may resolve the order of slip and flow enhancement of water in CNTs in computational studies.

Carbon nanostructures, especially carbon nanotubes and graphene nanopores, have been suggested for use in a wide range of purification and separation applications, from the desalination of seawater to the separation of liquids and gases. However, achieving the required high degree of selectivity among the molecules passing through the pores while maintaining rapid transport is a difficult challenge. Here, we examine the physical mechanisms by which nanopores distinguish between small ions and reject salts while passing water, as examples of how selectivity and purification can be achieved. The simple principles described can be utilized to design novel nanoporous materials for the separation of a wide range of gases, liquids, and solutes.

Biomaterials with antibacterial activity are widely developed for the treatment of bone infection. In the present study, hydroxyapatite (HAp) nanorods were prepared by green synthesis using Azadirachta indica and Coccinia grandis leaf extract. The prepared samples were characterized by various characterization techniques and the results indicate that the prepared samples are constituted of phase pure polycrystalline HAp having hexagonal crystal structure. Moreover, antibacterial activity test confirm that the HAp prepared using leaf extract as a solvent having significant antibacterial activity against Escherichia coli and Staphylococcus aureus. Hence, green synthesis can be a prospective way to develop orthopedic biomaterials with antibacterial properties.

Due to the recent outbreak of the Zika virus (ZIKV) in several regions, rapid, and accurate methods to diagnose Zika infection are in demand, particularly in regions that are on the frontline of a ZIKV outbreak. In this paper, three diagnostic methods for ZIKV are considered. Viral isolation is the gold standard for detection; this approach can involve incubation of cell cultures. Serological identification is based on the interactions between viral antigens and immunoglobulin G or immunoglobulin M antibodies; cross-reactivity with other types of flaviviruses can cause reduced specificity with this approach. Molecular confirmation, such as reverse transcription polymerase chain reaction (RT–PCR), involves reverse transcription of RNA and amplification of DNA. Quantitative analysis based on real-time RT–PCR can be undertaken by comparing fluorescence measurements against previously developed standards. A recently developed programmable paper-based detection approach can provide low-cost and rapid analysis. These viral identification and viral genetic analysis approaches play crucial roles in understanding the transmission of ZIKV.

Macroporous ceramics having unique pore morphologies with ceramic bridges, unidirectional cellular pores, and bamboo-like cells were fabricated by freezing gels with ceramic powder and various gelatin contents. Varying gel strengths were found to be effective for control of the pore architecture from open to closed pore channels. The proposed process is a relatively simple and versatile way to produce tailored pore configurations via a gelation freezing route. In addition, the relationship between the microstructure and mechanical properties of the resulting ceramics was discussed using a multiscale modeling technique, in which a homogenization method was conducted with microscopic models created from three dimensional images, global stress distributions in macroscopic samples by finite element method and local stress distributions. The simulation results were relatively consistent with the experimental results. The multiscale modeling technique was thus confirmed to be a strong tool for the prediction of the mechanical responses of porous ceramics.

The hydrobaric effect on photoactivity of titanium dioxide (TiO2) fabricated by cathodic deposition in an aqueous solution was evaluated in this study. When the applied pressure was increased to 35 MPa, the water-splitting performance was improved by almost fourfold of the performance of the TiO2 prepared at atmospheric pressure. The surface states effect was significant in the deposited TiO2, which was exploited to affect the charges recombination of TiO2, and thereby enhance the resultant photoelectrochemical water-splitting performance. The hydrobaric cathodic deposition could be extended to fabrication of other metal oxides to eliminate the negative influence from the high-temperature process.

In the recent years, several investigators are incorporating nanotechnology, one of the most powerful trendsetters in material research, to conventional polymer prepregs to enhance mechanical properties of composite strucutures. The current paper outlines the role of nanotechnology in reinforcing resin and challenges for fabricating nanomaterial reinforced prepregs. As delamination is the most critical problem for composite materials, the current study only focuses the application nanotechnology as a possible solution to alleviate delamination problems in laminated composites. The importance of nanoengineered prepregs is discussed in a viewpoint of improvement in interlaminar properties of the laminated composite materials.

Many material manufacturing techniques require the use of nonaqueous colloidal suspensions, containing well dispersed oxide particles and various water insoluble functional components. We report an efficient method for the direct transfer of MnO2 and titania particles, synthesized in water, to an organic solvent through the interface of two immiscible liquids. Particle agglomeration during the drying stage was avoided, and stable suspensions of nonagglomerated particles in the organic phase were obtained. The benefits of this method were demonstrated by the fabrication of advanced composite MnO2-multiwalled carbon nanotube electrodes, containing a polymer binder, for electrochemical supercapacitors with high active mass loading and high active material to current collector mass ratio. The electrodes showed a capacitance of 5.13 F/cm2 and low impedance. High extraction efficiency from concentrated suspensions was achieved by the use of an advanced extractor, which allowed strong adsorption on the particles by the polydentate bonding. The extraction mechanism is discussed.

A new rapid and energy saving method for the obtention of high performance nanoparticles and thin films of Nb2O5 by microwave-assisted hydrothermal synthesis is reported. The hydrothermal treatment of a sol–gel precursor solution in a microwave oven at 180 °C for 20 min was enough to obtain amorphous nanoparticles with average sizes of 40 nm. The calcination promotes the formation of different phases of Nb2O5 (TT and T) with pseudohexagonal and orthorhombic structure, respectively, that transform at higher temperatures in a mixture of orthorhombic and monoclinic phases. Crystalline phase composition was found to have a significant influence on the photocatalytic activity. The best photocatalytic performance was observed for the material mainly constituted by the TT-Nb2O5 phase. Thin films constituted by the TT phase were prepared by dip-coating. Photocatalytic experiments confirmed the high photocatalytic activity of this material, which showed a kinetic curve similar to that of a reference TiO2-P25 thin film.

Graphene has emerged as a champion material for a variety of applications cutting across multiple disciplines in science and engineering. Graphene and its derivatives have displayed huge potential as a biosensing material due to their unique physicochemical properties, good electrical conductivity, optical properties, biocompatibility, ease of functionalization, and flexibility. Their widespread use in making biosensors has opened up new possibilities for early diagnosis of life-threatening diseases and real-time health monitoring. Following an introduction and discussion on the significance of fabrication protocols and assembly, this review is intended to assess why graphene is suitable to build better biosensors, the working of existing biosensing schemes and their current status toward commercialization for wearable diagnostic and prognostic devices. We believe this review will provide a critical insight for harnessing graphene as a suitable biosensor for the clinical diagnostics, its future prospects and challenges ahead.

In this work, o-phenylenediamine-m-phenylenediamine copolymer dots (omCPs) with designed surface groups are synthesized and characterized. Here, we explored a simple, rapid semiquantitative detection system for Cu2+ with a wide detection range (5–7 orders of magnitude) based on the fluorescence in the solid state of omCPs and their tunable detection limits. The construction and application of the rapid semiquantitative detection system for Cu2+ are developed and demonstrated for the practical applications. What’s more, the detection limit can be modulated easily by adjusting the surface groups of these dots through the monomer dose control before the co-polymerization. Moreover, we demonstrated that this new technological approach is suitable for the semiquantitative determination of other ions pollutants (i.e., Na+, K+, Cu2+, Pb2+, Hg2+, and NO2 −) in environmental water.

In this study, SiC particle reinforced Al2024 matrix composites were fabricated by powder thixoforming (PT). Meanwhile, 2024 alloys were fabricated by permanent mold cast (PMC) and PT, respectively, to reveal superiorities of PT technology over the traditional processing technologies and the resulting composite over the matrix alloy. The microstructures and mechanical properties of the three materials were comparatively investigated. The results indicated that both the PT materials possessed finer spheroidal primary particles and smaller eutectic concentration, but the PMC alloy comprised large equiaxed grains, continuously net-shaped eutectic structures, and many porosities. The mechanical properties of the PT alloy were significantly higher than those of the PMC alloy because of the enhanced compactness and work hardening, decreased eutectic concentration, and fine primary particles. The incorporation of SiCp to the PT alloy further brought improvements, the ultimate tensile strength (UTS), yield strength (YS), and hardness were increased by 29.3% (UTS = 388 MPa), 35% (YS = 297 MPa), and 46.8% (hardness = 122.6 HV), respectively. A strengthening model considering different strengthening mechanisms and SiCp failure was proposed and YS of composite could be exactly predicted.