Search

The dissipation of charges by aging or under the effect of humid conditions considerably impedes a broader utilization of electrostatic fields in aerosol filtration. This study introduces a respiration‐driven air filter (RAF) that continuously generates triboelectric charges within a pair of tribolayers, which facilitates a sustained filtration performance. Such system is integrated in a multilayer unit that is inserted in personal protective equipment (RAFM) to efficiently capture, sense, and degrade airborne pollutants with no need for external power sources. The triboelectric nanogenerator‐based RAF continuously replenishes static charges and maintains an electrostatic field through breathing by the effect of contact‐electrification between two cellulose‐based tribolayers: a cellulose/metal organic framework cryogel (electron donor) and a cellulose–based electrospun membrane (electron acceptor). Notably, the triboelectric field of the RAF's tribolayer pair substantially enhances both the filtration efficiency (up to 93.8% for 0.3 µm particulate matter) and sensing/catalytic degradation (ammonia; degradation >20%). When integrated in a circuit module, the RAFM effectively monitors respiration dynamics, acting as a breathing indicator/regulator. Overall, this study adds to the promise of tribogeneration through cellulose‐based materials and its application in exposure‐risk operations. [ABSTRACT FROM AUTHOR]

The influence of odd viscosity on the instability of a liquid film flowing along a porous inclined plane under a normal electric field is investigated. It is assumed that the flow at the porous inclined plane satisfies the Beavers–Joseph slip boundary condition. By utilizing the long-wave approximation and employing the method of systematic asymptotic expansion, a nonlinear evolution equation for the film thickness under the influence of the electric field is derived. The stability analysis of this evolution equation reveals that the odd viscosity of the film has a stabilizing effect, while the electric field has a destabilizing effect. Additionally, the permeability of the porous inclined plane enhances the instability of the liquid film flow. Numerical simulations are conducted using a fast Fourier transform algorithm to solve the nonlinear evolution equations. The numerical results demonstrate that, within the stable region and with all parameters fixed, the wave amplitude decreases as the evolution time increases, indicating a gradual stabilization of the liquid film flow. Conversely, in the unstable region, the opposite behavior is observed. As the evolution time increases, the fluctuation amplitude grows larger, resulting in a gradual destabilization of the liquid film flow. Furthermore, when the evolution time is kept constant and the odd viscosity coefficient is nonzero, the film exhibits greater stability. The amplitude of the wave increases with the electrical parameter E. In the unstable region, an increase in the permeability β of the porous medium leads to a tendency for the film flow to stabilize. [ABSTRACT FROM AUTHOR]

In this work, we study the unsteady electro‐osmotic flow of fractional viscoelastic fluids in micro‐parallel channels, where the velocity slip effect on the walls is also considered. The analytical solution is obtained through solving the Cauchy momentum equation, together with the linearized Poisson–Boltzmann equation and the fractional Maxwell constitutive equation. The influences of the normalized electrokinetic width K, Deborah number De, slip length L and fractional derivative α on the velocity and volume flow rate are discussed. The results demonstrate that the dimensionless parameters L, De and K all have a promoting effect on the electro‐osmotic flow and resonance behavior of fractional Maxwell fluids. In addition, compared with the classical Maxwell fluid, the microstructure of the fractional Maxwell fluid weakens the resonance behavior. [ABSTRACT FROM AUTHOR]

China is currently at an important stage of urbanization. In recent years, the number and scale of under-lake tunnels in southern cities of China are growing consistently, which brings opportunities and challenges in intelligent construction and operation maintenance. Due to the long length of the under-lake tunnel, the large volume of concrete to be cast, the complex environment of the buried section and the underground environment of the lake bottom, the hydration heat and stress crack have been the main challenges of the under-lake tunnel engineering in crack control and waterproofing aspect. Simultaneously, with the development of big data, intelligent construction, information technology, and other techniques, these techniques are gradually applied to the whole life cycle of tunnel engineering including survey, design, construction, operation, and maintenance. The construction of the lake tunnel project is setting off a new round of technological innovation. This paper systematically summarizes the technical breakthroughs and application of technologies such as intelligent construction and information technology in the construction of under-lake tunnels in China, and puts forward reasonable suggestions on the key technologies of intelligent construction and operation maintenance for urban under-lake tunnel engineering.

Thermal degradation behaviors of one composite constituted by poly(lactic acid) (PLA), cellulose nanofibrils (CNF), and lignin–cellulose nanofibrils (LCNF) in a nitrogen atmosphere were studied using thermogravimetric analysis (TGA). It was found that the thermal degradation stability of the PLA/LCNF composite was improved when compared to PLA and PLA/CNF. The Flynn–Wall–Ozawa method was used to determine the apparent activation energy of the composite samples which was based on a set of TGA data obtained at different heating rates. It was shown that the conversion functions calculated by means of the Coats–Redfern method depend on a set of kinetic models, which could be concluded that using the model-fitting methods couldn't reveal the complexity of the thermal degradation process and the isokinetic relationship method was used to estimate a model-independent pre-exponential factor (ln A) corresponding to a given degree of conversion. [ABSTRACT FROM AUTHOR]