Phonon Localization in Boron Nitride Nanotubes: Mixing Effect of 10B Isotopes and Vacancies

We explored the mixing effect of 10B isotopes and boron (B) or nitrogen (N) vacancies on the atomic vibrational properties of (10, 0) single-wall boron nitride nanotubes (BNNT). The forced oscillation technique was employed to evaluate the phonon modes for the entire range (0-100%) of 10B isotopes and atomic vacancy densities ranging from 0 to 30%. With increasing isotope densities, we noticed a blue-shift of the Raman active A1 phonon peak, whereas an increased density of mixed or independent B and N vacancies resulted in the emergence of a new low-frequency peak and the annihilation of the A1 peak in the phonon density-of-states. High-energy optical phonons were localized as a result of both 10B isotopes and the presence of mixing defects. We generated typical mode patterns for different defects to show the phonon localization processes due to the defects. We found an asymmetrical nature of the localization length with increasing 10B isotope content, which corresponds well with the isotope inherited localization length of carbon nanotubes and mono-layer graphene. The localization length falls abruptly with the increase in concentration of both atomic vacancies (B or N) and mixing defects (10B isotope and vacancies). These findings are critical for understanding heat conduction and nanoscopic vibrational investigations like tip-enhanced Raman spectra in BNNT, which can map local phonon energies.

Analysis of Maxwell bioconvective nanofluids with surface suction and slip conditions in the presence of solar radiations

Several researchers have studied nanofluids over the past several decades and tried to identify potential agents that are added to nanofluids (nanoparticle suspensions) with tremendous thermal conductivity. In such suspensions, the Brownian motion of nanoparticles is the only means expected to be associated with the improved thermal conductivity of nanofluids, and the sections that may add to this are the subject of main conversation and discussion. In the current evaluation, the effect of Brownian motion has been investigated by injecting nanoparticles into the base fluid, and the existing fundamental information is available at creation. Propagation results show that this mixing effect can significantly increase the thermal conductivity of nanofluids. One of the interesting features of this model is that the temperature can be increased by the energy of sunlight, which is required for some industrial processes. The stretching property of the sheet is more conducive to the temperature rise. This model contains features that have not been previously studied, which is driving demand for this model in a variety of industries, now and in future generations.

Interactions among litter chemical traits alter the non-additive effect of litter mixing

Litter decomposition is a fundamental nutrient cycling process, and litter diversity decreases induced by biodiversity loss have substantial effects on soil carbon cycling. However, few experimental studies have characterized the effect of litter diversity on and litter chemistry. Here, we used single-species and mixed litters to study the effects of litter chemical properties on the direction, intensity and drivers of non-additive litter-mixing effects. We found that 1) there was no significant effect of litter species richness on soil processes, and the litter chemistry of component species was more robust to soil respiration and non-additive effects. 2) The early-stage mixing effect was negative, ranging from -3.1 to -0.3, and its magnitude was strongest in chemically diverse litter mixtures; the late-stage mixing effect ranged from -2.3 to 1.3, and the non-additive effect of chemically similar species was positive. 3) Litter carbon, lignin, phenols and soluble sugar affected early-stage soil respiration, and litter carbon, nitrogen, phenols, and condensed tannins affected late-stage soil respiration, which accounted for 46% and 56% of the variation in early- and late-stage soil respiration, respectively. 4) Compared with plant species richness, litter chemistry altered the direction and magnitude of litter mixing, and litter chemical composition (including litter chemical traits and their interactions) had a stronger effect on non-additive effects than variation in single chemical compounds according to the R value (R=0.36). 5) Artemisia halodendron, as a key sand-fixing plant species, will accelerate nutrient cycling, but it has negative effects on carbon cycling when mixed with other plant species

Numerical study of a fractal-like tree node micromixer based on Murray’s law

This article focuses on the influence of fractal-like tree node (FTN) on the mixing efficiency and pressure drop of the micromixer. The mixing efficiency of FTN micromixers with different branch angle δ = 30°, 60° and 90° are compared at six kinds of Reynolds (Res). We can get that the micromixer with δ = 90° has higher mixing efficiency at any Re. The mixing results of the center FTN and the stagger FTN micromixer show that the center FTN has better mixing effect. The angle of FTN and the number of FTN are the key to improve the mixing efficiency. They are also the key to change the pressure drop in the microchannel. The FTN can slow down the pressure drop and maintain the stable pressure drop between two adjacent FTNs. The way to obtain a more stable pressure range is to increase the distance between two adjacent FTN. This provides a reliable reference for maintaining a stable pressure in the microchannel.

An Index for Quantitative Evaluation of the Mixing in Ethanol Precipitation of Traditional Chinese Medicine

(1) Background: Ethanol precipitation is widely used in the manufacturing traditional Chinese medicines (TCMs). Insufficient mixing of ethanol solution and concentrate usually results in the coating loss of active ingredients. However, there is no index for quantitative evaluation of the mixing in ethanol precipitation. Therefore, this study aimed to define an index for quantitative evaluation of the mixing effect in ethanol precipitation of TCMs. (2) Methods: The concept and requirements of a mixing indicator were proposed. The mass percentage of concentrate fully mixed with ethanol solution (well-mixing ratio, WMR) was used as an index to evaluate the mixing effect. The formula for calculation of WMR was derived. The utility of the WMR was evaluated on stirring devices and a micromesh mixer. (3) Results: Increasing stirring speed, decreasing total solid content of the concentrate, and decreasing the diameter of the ethanol solution droplets all resulted in higher retention rates for lobetyolin and higher WMR. The WMR increased with the increasing flow rate of the concentrate and ethanol solution in the micromesh mixer. The mixing of ethanol solution and concentrate was better when using a micromesh mixer with a smaller internal mixing zone. The results revealed that WMR could be used to quantitatively characterize the mixing of concentrate and ethanol solution, although it has some limitations. (4) Conclusions: The proposed index WMR could guide quality control of the TCM ethanol precipitation process. This study represents a new contribution to improving ethanol precipitation equipment, optimizing process parameters, and enhanced properties of concentrate for TCM enterprises.

A simulation study of nonideal mixing effect on the dynamic response of an exothermic CSTR with Cholette’s model

The study of nonideal mixing effect on the dynamic behaviors of CSTRs has very rarely been published in the literature. In this work, Cholette’s model is employed to explore the nonideal mixing effect on the dynamic response of a nonisothermal CSTR. The analysis shows that the mixing parameter n (the fraction of the feed entering the zone of perfect mixing) and m (the fraction of the total volume of the reactor), indeed affect the characteristic roots of transfer function of a real CSTR, which determine the system stability. On the other hand, the inverse response and overshoot response are also affected by the nonideal mixing in a nonisothemal CSTR. These results are of much help for the design and control of a real CSTR.

Research on the Construction Technology of Self-Monitoring Asphalt Concrete

Combined with the paving of the test section of Self-monitoring Asphalt Concrete, the electrode burying mode of pavement construction is designed according to its characteristics, and the best mixing method and spreading rolling construction technology are compared and analyzed. The results show that the construction structure of the test section is reasonable and feasible, the best mixing effect can be obtained by adding conductive phase material and asphalt at the same time, and the rolling process. The order of rubber wheel and steel wheel compaction has no significant effect on compaction degree.