Correction to: Impact of Size Distribution of Cell Model on the Effective Thermal Conductivity of Saturated Porous Media

International Journal of Thermophysics - The addition of nanoparticles to base fuel may bring about remarkable changes in a thermodynamic process such as evaporation, due to the intensified...     

Improved aqueous solubility,bioaccessibility and cellular uptake of quercetin following pH-driven encapsulation in whey protein isolate

The purpose of this study was to increase the water solubility and potential bioavailability of quercetin by encapsulation in whey protein isolate (WPI) based on a green, efficient pH-driven method. According to the results, the water solubility of quercetin increased by 346.9: times after loading into WPI nanoparticles. When the initial quercetin concentration was 0.25 mg mL⁻¹ and WPI was 2% w/v, the encapsulation efficiency reached 94.1%, the Z-average diameter was 36.63 nm, and the zeta potential was −36.4 mV at pH 7.0. The fluorescence spectroscopy assay suggested the molecular complexation of quercetin and WPI at pH 12.0. X-ray diffraction assay indicated the enclosure of amorphous quercetin in WPI. Correspondingly, the bioaccessibility increased from 2.76% to 31.23% and the Caco-2 cell monolayer uptake increased from 0% to 2.12% after nanoencapsulation. This work confirmed that the pH-driven method is an effective approach to prepare WPI–quercetin nanocapsules to improve physical and potentially biological properties of quercetin.     

Effect of obstacles on the detonation diffraction and subsequent re-initiation

The DCRFoam solver (density-based compressible solver) built on the OpenFOAM platform is used to simulate the reflection and diffraction processes that occur when detonation waves collide with various objects. Static stoichiometric hydrogen–oxygen mixtures diluted with 70% Ar are used to form stable detonation waves with large cells, with initial conditions of 6.67 kPa pressure and 298 K temperature. The diameters of the cylindrical obstacle range from 6 mm to 22 mm, with x = 230 mm, x = 244 mm, and x = 257 mm being the chosen position. Cylindrical, square, triangular, and inverted triangular obstacles are used, and the quenched detonation re-initiation processes behind them are investigated. In the detonation diffraction process, four triple points exist at the same time due to the effect of cylindrical obstacles of smaller diameters. The re-initiation distance of the detonation wave increases with the increase of cylindrical obstacle diameter. Both the Mach reflection angle and the decoupled angle decrease as the diameter increases. When the location of the cylindrical obstacles is changed, the detonation wave dashes into the obstacles with its different front structures, it is easier to realize the detonation re-initiation when the weak incident shock at the front of a detonation wave strikes the obstacles, and the re-initiation distance decreases by 17.1% when compared with the longest re-initiation distance. The detonation re-initiation distance is shortest under the action of cylindrical obstacles, however the quenched detonation cannot be re-initiated when the inverted triangle and square obstacles are used. The suppression effects of inverted triangle and square obstacles on detonation waves are more evident.     

Theoretical study the component and facet dependence of HER performance on nickel phosphides surfaces

Energy depletion and environmental pollution are still serious challenges for human beings. The application of hydrogen energy should be a promising strategy to address this issue. However, the hydrogen production should be one shortcoming for hydrogen energy. The hydrogen evolution reaction (HER) based on electrocatalysis is an effective way to enhance the hydrogen generation with small energy consumption under ambient conditions. Many works have been devoted to develop high performance catalysts to satisfy the HER processes. Nevertheless, the mechanism about facet-dependence and composition-dependence influence is still need to deeply study. Hereon, based on density functional theory calculations, the [100], [110], and [111] facets of Ni_xP_y (Ni₃P, Ni₂P, NiP, NiP₂, NiP₃) systems were created and their HER catalytic activity were used to reveal the underline mechanism. By analyzing the variation of Gibbs free energy, it was found that the structural composition has a greater effect on HER than the facet. Significantly, the Ni₂P(111) surface with Ni/P-termination has the best HER performance for all samples in present work. Through exploring the electron transfer of H with surrounding atoms during the HER process, the H adsorption mechanism as well as its reaction mechanism has been revealed. The deep insights in this work provide an important fundamental that the contents of non-metal for compounds catalysts can heavily influence the performance of HER, which should give more guidance for designing new catalysts.     

Study on ice-melting performance of gradient gas diffusion layer in proton exchange membrane fuel cell

In this study, a three-dimensional model was established using the lattice Boltzmann method (LBM) to study the internal ice melting process of the gas diffusion layer (GDL) of the proton exchange membrane fuel cell (PEMFC). The single-point second-order curved boundary condition was adopted. The effects of GDL carbon fiber number, growth slope of the number of carbon fibers and carbon fiber diameter on ice melting were studied. The results were revealed that the temperature in the middle and lower part of the gradient distribution GDL is significantly higher than that of the no-gradient GDL. With the increase of the growth slope of the number of carbon fiber, the temperature and melting rate gradually increase, and the position of the solid-liquid interface gradually decreases. The decrease in the number of carbon fibers has a similar effect as the increase in the growth slope of the number of carbon fibers. In addition, as the diameter of the carbon fiber increases, the position of the solid-liquid interface gradually decreases first and then increases.     

Tempering–preservation treatment inactivated lipase in wheat bran and retained phenolic compounds

Wheat bran is rich in functional ingredients, but the high level of lipase limits its applications. Tempering–preservation treatment (at 70–90 °C with moisture of 20%–40% for 1–4 h) was exploited for stabilising wheat bran and its effect on polyphenols was investigated. The results showed that more lipase was inactivated at higher tempering moisture, temperature and longer time. The optimum condition for inactivation of wheat bran lipase was 30% moisture and 90 °C for 4 h. The inactivation rate reached 93.8% with a residual enzyme activity of 0.264 U g⁻¹. Under the optimum condition, the sum of free phenolic acids rose from 25.4 to 55.8 µg g⁻¹. As for bound phenolic acids, there was a slight increase of hydroxybenzoic acid derivatives but a slight decrease of hydroxycinnamic acid derivatives. The total contents of phenolic acids before and after stabilisation were not significantly different. This study showed the possibility of using tempering–preservation as an efficient method for inactivation of wheat bran lipase while maintaining its phenolic compounds, which could be used in the production of whole wheat flour.     

Numerical study on laminar burning velocity of ammonia flame with methanol addition

The combustion characteristics of ammonia/methanol mixtures were investigated numerically in this study. Methanol has a dramatic promotive effect on the laminar burning velocity (LBV) of ammonia. Three mechanisms from literature and another four self-developed mechanisms constructed in this study were evaluated using the measured laminar burning velocities of ammonia/methanol mixtures from Wang et al. (Combust.Flame. 2021). Generally, none of the selected mechanisms can precisely predict the measured laminar burning velocities at all conditions. Aiming to develop a simplified and reliable mechanism for ammonia/methanol mixtures, the constructed mechanism utilized NUI Galway mechanism (Combust.Flame. 2016) as methanol sub-mechanism and the Otomo mechanism (Int. J. Hydrogen. Energy. 2018) as ammonia sub-mechanism was optimized and reduced. The reduced mechanism entitled ‘DNO-NH3’, can accurately reproduce the measured laminar burning velocities of ammonia/methanol mixtures under all conditions. A reaction path analysis of the ammonia/methanol mixtures based on the DNO-NH3 mechanism shows that methanol is not directly involved in ammonia oxidation, instead, the produced methyl radicals from methanol oxidization contribute to the dehydrogenation of ammonia. Besides, NO_x emission analysis demonstrates that 60% methanol addition results in the highest NO_x emissions. The most important reactions dominating the NO_x consumption and production are identified in this study.     

Dual effect synergistically triggered Ce:(Y,Tb)3(Al,Mn)5O12 transparent ceramics enabling a high color-rendering index and excellent thermal stability for white LEDs

Ce:Y₃Al₅O₁₂ transparent ceramics (TCs) with appropriate emission light proportion and high thermal stability are significant to construct white light emitting diode devices with excellent chromaticity parameters. In this work, strategies of controlling crystal-field splitting around Ce³⁺ ion and doping orange-red emitting ion, were adopted to fabricate Ce:(Y,Tb)₃(Al,Mn)₅O₁₂ TCs via vacuum sintering technique. Notably, 85.4 % of the room-temperature luminescence intensity of the TC was retained at 150 °C, and the color rendering index was as high as 79.8. Furthermore, a 12 nm red shift and a 16.2 % increase of full width at half maximum were achieved owing to the synergistic effects of Tb³⁺ and Mn²⁺ ions. By combining TCs with a 460 nm blue chip, a warm white light with a low correlated color temperature of 4155 K was acquired. Meanwhile, the action mechanism of Tb³⁺ ion and the energy transfer between Ce³⁺ and Mn²⁺ ions were verified in prepared TCs.     

In situ Raman spectroscopic study towards the growth and excellent HER catalysis of Ni/Ni(OH)2 heterostructure

The electrochemical water splitting to produce H₂ in high efficiency with earth-abundant-metal catalysts remains a challenge. Here, we describe a simple “cyclic voltammetry + ageing” protocol at room temperature to activate Ni electrode (AC-Ni/NF) for hydrogen evolution reaction (HER), by which Ni/Ni(OH)₂ heterostructure is formed at the surface. In situ Raman spectroscopy reveals the gradual growth of Ni/Ni(OH)₂ heterostructure during the first 30 min of the aging treatment and combined with polarization measurements, it suggests a positive relation between the Ni/Ni(OH)₂ amount and HER performance of the electrode. The obtained AC-Ni/NF catalyst, with plentiful Ni–Ni(OH)₂ interfaces, exhibits remarkable performance towards HER, with the low overpotential of only 30 mV at a H₂-evolving current density of 10 mA/cm² and 153 mV at 100 mA/cm², as well as a small Tafel slope of 46.8 mV/dec in 1 M KOH electrolyte at ambient temperature. The excellent HER performance of the AC-Ni/NF could be maintained for at least 24 h without obvious decay. Ex situ experiments and in situ electrochemical-Raman spectroscopy along with density functional theory (DFT) calculations reveal that Ni/Ni(OH)₂ heterostructure, although partially reduced, can still persist during HER catalysis and it is the Ni–Ni(OH)₂ interface reducing the energy barrier of H1 adsorption thus promoting the HER performance.     

ZnIn2S4/In(OH)3 hollow microspheres fabricated by one-step l-cysteine-mediated hydrothermal growth for enhanced hydrogen production and MB degradation

An intervening barrier for photocatalytic water decomposition and pollutant degradation is the frustratingly quick recombination of e⁻ - h⁺ pairs. Delicate design of heterojunction photocatalysts by coupling the semiconductors at nanoscale with well-matched geometrical and electronic alignments is an effective strategy to ameliorate the charge separation. Here a facile and environment-friendly l-cysteine-assisted hydrothermal process under weakly alkaline conditions is demonstrated for the first time to fabricate ZnIn₂S₄/In(OH)₃ hollow microspheres with intimate contact, which are verified by XRD, SEM, (HR)TEM, XPS, N₂ adsorption-desorption, UV–Vis DRS and photoluminescence spectra. ZnIn₂S₄/In(OH)₃ heterostructure (L-cys/Zn²⁺ = 4, molar ratio) with a band-gap of 2.50 eV, demonstrates the best photocatalytic performance for water reduction and MB degradation under visible light, outperforming its counterparts (In(OH)₃ and ZnIn₂S₄). The excellent activity of ZnIn₂S₄/In(OH)₃ heterostructure arises from the intercrossed band-edge positions as well as the unique hollow structure with large surface area and wide pore-size distribution, which are beneficial for the efficient charge migration from bulk to surface as well as at the interface between ZnIn₂S₄ and In(OH)₃. This work provides an efficient and eco-friendly strategy for one-pot synthesis of heterostructured composites with intimate contact for photocatalytic application.