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The wettability of lubricant oil produces a velocity slip at the water–lubricant oil interface when the lubricant oil contacts the rectangular microgroove, leading to a reduction in the friction resistance at the boundary wall. However, lubricant oil is highly susceptible to changes in external shear force and can escape from the rectangular microgroove, degrading its slippery properties. This study investigated the influence of wettability and structure width on the stability and drag reduction performance of lubricant oil via simulation. The results indicated that lubricant oil stability is related to wettability and structural width. The lubricant oil remained stable at contact angles of 1° and 150° and a width of 0.4 mm. Based on slip velocity, the maximum drag reduction at a width of 0.6 mm in a turbulent environment was 13.4%. Our findings could provide valuable insights into surface design using lubricant oil, helping researchers avoid detrimental designs and enhance sustainable drag reduction performance. [ABSTRACT FROM AUTHOR]

Applying a NOx trap catalyst to effectively remove NOx contaminants from the oxygen–rich exhaust is still very challenging, due to the lack of use guidance based on deactivation mechanisms. The temperature–dependent Pt sintering rate constant was described using Pt dispersion determined by pulse CO chemisorption. It was found that 700–850 °C was the determining temperature regions for the significant Pt sintering, according to the sintering kinetics and the evolution of active Ptδ+ sites. The weak basicity plays a critical role in trapping NOx at low–temperature (≤300 °C), and the NOx trap efficiency decreases because of the loss of catalytic activity and medium basicity caused by forming BaAl2O4 phase. The reduction of NOx towards N2 on the Pt crystallites smaller than 18 nm is structure sensitive and decreases with losing the reducibility of catalysts. The security for long–time use of a NOx trap catalyst should be exposed to the exhaust gas within 750 °C, and effectively removing NOx contaminants requires it to be worked in the 350–500 °C regions. These findings can guide engineers and applied chemists how to efficiently use a NOx trap catalyst in the automotive exhaust purification system. [ABSTRACT FROM AUTHOR]

Passive NOx adsorber (PNA) is one of the important means to effectively reduce NOx emission control in the cold start of a diesel engine. A series of Pd/SSZ-13 catalysts with different SiO2/Al2O3 ratios (11, 17, and 25) were prepared using the impregnation method. Furthermore, the effect of the SiO2/Al2O3 ratio on the adsorption performance of Pd/SSZ-13 at low-temperature NOx under realistic exhaust conditions was studied. The results show that the Pd/SSZ-13 catalyst with a low SiO2/Al2O3 ratio after loading Pd has a higher specific surface area and palladium ion content. There is a negative correlation between NOx adsorption performance and the SiO2/Al2O3 ratio. After high-temperature heat treatment, the acid sites closely related to palladium species increase and palladium species will redisperse, producing more palladium ions. The palladium ions coexist in Pd/SSZ-13 in the form of Pd2+ and Pd+, among which Pd2+ is divided into two types: Z−Pd2+Z− and Z−[Pd(II)OH]+. The NOx adsorption performance of the Pd/SSZ-13 catalyst was significantly improved, and the higher the SiO2/Al2O3 ratio, the more obviously the advantage of NOx adsorption performance increased after heat treatment. The NOx adsorption kinetic model of the Pd/SSZ-13 catalyst under realistic exhaust conditions was most suitably described by the pseudo-first-order model. [ABSTRACT FROM AUTHOR]

The morphology and size control of anisotropic nanocrystals are critical for tuning shape-dependent physicochemical properties. Although the anisotropic dissolution process is considered to be an effective means to precisely control the size and morphology of nanocrystals, the anisotropic dissolution mechanism remains poorly understood. Here, using in situ liquid cell transmission electron microscopy, we investigate the anisotropic etching dissolution behaviors of polyvinylpyrrolidone (PVP)-stabilized Ag nanorods in NaCl solution. Results show that etching dissolution occurs only in the longitudinal direction of the nanorod at low chloride concentration (0.2 mM), whereas at high chloride concentration (1 M), the lateral and longitudinal directions of the nanorods are dissolved. First-principles calculations demonstrate that PVP is selectively adsorbed on the {100} crystal plane of silver nanorods, making the tips of nanorods the only reaction sites in the anisotropic etching process. When the chemical potential difference of the Cl - concentration is higher than the diffusion barrier (0.196 eV) of Cl - in the PVP molecule, Cl - penetrates the PVP molecular layer of {100} facets on the side of the Ag nanorods. These findings provide an in-depth insight into the anisotropic etching mechanisms and lay foundations for the controlled preparation and rational design of nanostructures., (© 2024 IOP Publishing Ltd.)

FcepsilonRI expression and function is a central aspect of allergic disease. Using bone marrow-derived mouse mast cell populations, we have previously shown that the Th2 cytokine IL-4 inhibits FcepsilonRI expression and function. In the current study we show that the Th2 cytokine IL-10 has similar regulatory properties, and that it augments the inhibitory effects of IL-4. FcepsilonRI down-regulation was functionally significant, as it diminished inflammatory cytokine production and IgE-mediated FcepsilonRI up-regulation. IL-10 and IL-4 reduced FcepsilonRI beta protein expression without altering the alpha or gamma subunits. The ability of IL-4 and IL-10 to alter FcepsilonRI expression by targeting the beta-chain, a critical receptor subunit known to modulate receptor expression and signaling, suggests the presence of a Th2 cytokine-mediated homeostatic network that could serve to both initiate and limit mast cell effector function.