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Efficient internal mixing stands as a pivotal requirement for droplet-based micro-reactors/micro-mixers facilitated by microfluidic systems. Among the various methods for their production, capillary-generated droplets emerge as a notable approach. Understanding the role of coaxiality within coflow microfluidic devices in influencing internal mixing remains a crucial aspect for optimizing these systems. Coaxiality within inserted cylindrical capillaries significantly affects mixing efficiency according to our experimental observations. Through numerical simulations, the intricate mixing dynamics of reagents inside droplet generated via a coflow capillary microfluidic system has been investigated. We demonstrate that coaxiality profoundly impacts the initial distribution of disperse phases within droplets, shaping subsequent internal mixing dynamics. Contrary to previous assumptions, our findings highlight the substantial impact of marginal deviations in coaxiality, around 20%, on optimizing mixing efficiency. This challenges prior beliefs and emphasizes the nuanced role of coaxiality in microfluidic systems. These insights advance our understanding of coaxiality's critical influence on enhancing mixing efficiency within coflow microfluidic devices, paving the way for improved design strategies and applications in diverse scientific fields. [ABSTRACT FROM AUTHOR]

The resistance of a large Pure Car Truck Carrier (PCTC) with a bulbous bow and a transom stern is evaluated in the present paper. Several cases at nine different ship speeds in calm water are simulated and results are compared with the experimental measurements. The maximum relative error is 0.93% at a Froude number (Fr) of 0.209. The total resistance coefficient of the ship in calm water shows a parabolic trend with increasing Fr, and it reaches a minimum value at Fr = 0.1794. Furthermore, the cases of the ship in regular waves with six different wavelengths and three wave heights are simulated. It is observed that the total resistance exhibits a quadratic relationship with the wavelength when the wave height is fixed. The wave-making resistance increases with the increase in wave height at any fixed wavelength, and it reaches a maximum value when the wave-length is 1.2 times the ship length (Lpp). Additionally, we also investigated the resistance in three different sea states at four different speeds. When the significant wave height of irregular waves is the same as regular waves, the wave-making resistance under irregular waves is much smaller than that of the regular waves. All of these results indicate that the bulbous bow and transom stern can reduce the wave-making and residuary resistances, which can provide a useful reference for the subsequent design and manufacturing of related ships. [ABSTRACT FROM AUTHOR]

Chlorine species, widely presented in industrial flue gas such as the waste incineration plants, can poison the catalysts and affect the selective catalytic reduction (SCR) performance. In this work, effects of Cl on the SCR performance of V2O5–WO3/TiO2 (VW/Ti) catalysts were investigated by NH4Cl deposition. The results showed that the NOx conversion efficiency at low reaction temperature (< 300 °C) decreased with the loading of NH4Cl after calcination. It was found that instead of causing the chlorination of VW/Ti catalyst the NH4Cl decomposed into volatile Cl species due to the weak V–Cl bonding. Such decomposition reduced significantly the surface non-lattice oxygen species to inhibit NO adsorption and activation, but hardly affected the redox ability and acidity of VW/Ti catalyst. Time–resolved in situ DRIFTs results indicated that NH3 activation and the SCR process predominated by Eley–Rideal mechanism were not influenced with NH4Cl impregnation, while the SCR at low temperature following a Langmuir–Hinshelwood path was limited by the decreased and weaker binding sites for NO activation. [ABSTRACT FROM AUTHOR]

Selective catalytic reduction of NOx by ammonia (NH3‐SCR) was affected by HCl, which was widely present in industrial flue gas. In this study, the SCR performances over MOx‐WO3/TiO2 (MW/Ti, M=Mn, Ce and V) catalysts after HCl treatment were investigated. It was found that HCl poisoning showed inhibition and promotion in NOx conversion over MnW/Ti and CeW/Ti catalysts, respectively. While the SCR activity over VW/Ti catalyst was hardly affected by HCl. Over MnW/Ti catalyst, the rupture of the Mn−O bond by the strong Mn−Cl binding induced the formation of amorphous MnCl2 species. This Cl‐containing species with Mn in a low oxidation state exhibited poorer redox ability and NO activation, resulting in a decrease in low‐temperature SCR activity. However, instead of directly affecting the CeOx and VOx sites, gaseous HCl reacted with NH3 to form NH4Cl species on the surface of CeW/Ti and VW/Ti catalysts. As a result, the SCR activity of VW/Ti catalyst was scarcely influenced by HCl, taking the unchanged redox ability and NH3 adsorption. With a further accumulation of NH4Cl on CeW/Ti catalyst, the NOx conversion at low temperature was evidently enhanced due to the promotion in NO‐to‐NO2 conversion (Fast‐SCR). [ABSTRACT FROM AUTHOR]

Selective catalytic reduction of NOx by ammonia (NH3‐SCR) was affected by HCl, which was widely present in industrial flue gas. In this study, the SCR performances over MOx‐WO3/TiO2 (MW/Ti, M=Mn, Ce and V) catalysts after HCl treatment were investigated. It was found that HCl poisoning showed inhibition and promotion in NOx conversion over MnW/Ti and CeW/Ti catalysts, respectively. While the SCR activity over VW/Ti catalyst was hardly affected by HCl. Over MnW/Ti catalyst, the rupture of the Mn−O bond by the strong Mn−Cl binding induced the formation of amorphous MnCl2 species. This Cl‐containing species with Mn in a low oxidation state exhibited poorer redox ability and NO activation, resulting in a decrease in low‐temperature SCR activity. However, instead of directly affecting the CeOx and VOx sites, gaseous HCl reacted with NH3 to form NH4Cl species on the surface of CeW/Ti and VW/Ti catalysts. As a result, the SCR activity of VW/Ti catalyst was scarcely influenced by HCl, taking the unchanged redox ability and NH3 adsorption. With a further accumulation of NH4Cl on CeW/Ti catalyst, the NOx conversion at low temperature was evidently enhanced due to the promotion in NO‐to‐NO2 conversion (Fast‐SCR). [ABSTRACT FROM AUTHOR]

Selective catalytic reduction of nitrogen oxides (NOx) with C3H6 (C3H6‐SCR) was investigated over NiO catalysts supported on different metal‐oxides. A NiAlOx mixed oxide phase was formed over NiO/γ‐Al2O3 catalyst, inducing an immediate interaction between NiOx and AlOx species. Such interaction resulted in a charge transfer from Ni to Al site and the formation of Ni species in high oxidation state. In comparison to other NiO‐loaded catalysts, NiO/γ‐Al2O3 catalyst exhibited the highest NOx conversion at temperature higher than 450 °C, but a poor C3H6 oxidation activity due to the decreased nucleophilicity for surface oxygen species. By temperature‐programed NO oxidation, it is indicated that nitrate species were rapidly formed and stably maintained at high temperature over NiO/γ‐Al2O3 catalyst. In situ transient reactions further verified the Langmuir–Hinshelwood mechanism for C3H6‐SCR, where both gaseous NO and C3H6 were adsorbed and activated on catalyst surface and reacted to generate N2. Due to the strong metal‐support interaction over NiO/γ‐Al2O3 catalyst, both nitrate and CxHyOz intermediates were well preserved to attain high C3H6‐SCR activity. [ABSTRACT FROM AUTHOR]

Selective catalytic reduction of nitrogen oxides (NOx) with C3H6 (C3H6‐SCR) was investigated over NiO catalysts supported on different metal‐oxides. A NiAlOx mixed oxide phase was formed over NiO/γ‐Al2O3 catalyst, inducing an immediate interaction between NiOx and AlOx species. Such interaction resulted in a charge transfer from Ni to Al site and the formation of Ni species in high oxidation state. In comparison to other NiO‐loaded catalysts, NiO/γ‐Al2O3 catalyst exhibited the highest NOx conversion at temperature higher than 450 °C, but a poor C3H6 oxidation activity due to the decreased nucleophilicity for surface oxygen species. By temperature‐programed NO oxidation, it is indicated that nitrate species were rapidly formed and stably maintained at high temperature over NiO/γ‐Al2O3 catalyst. In situ transient reactions further verified the Langmuir–Hinshelwood mechanism for C3H6‐SCR, where both gaseous NO and C3H6 were adsorbed and activated on catalyst surface and reacted to generate N2. Due to the strong metal‐support interaction over NiO/γ‐Al2O3 catalyst, both nitrate and CxHyOz intermediates were well preserved to attain high C3H6‐SCR activity. [ABSTRACT FROM AUTHOR]