Leakage Retardation of Static Seals via Surface Roughness and Wettability Modification.

In this paper, the effects of surface roughness and wettability on the leakage performance of static seals were highlighted. The results show that the leakage rate is negatively correlated with the contact pressure and positively correlated with surface roughness. Surface wettability affects leakage performance. Leakage retardation is achieved by modifying the roughness and wettability at the interface. The seal interface consists of two oleophobicity surfaces and exhibits an excellent seal performance, of which the leakage reduction is approximately 64%. A theoretical model based on wettability is established to predict the leakage rates under varying wettability conditions, and its validity is confirmed. This research result is expected to be applied in the field of seals and predict the leakage performance of interfaces with different wettabilities to minimize and reduce the leakage of oil in static sealing systems.

Research progress of industrial wastewater treatment technology based on solar interfacial adsorption coupled evaporation process.

Solar interface evaporation is an effective method for the treatment of water that has low energy consumption. Adsorption is recognized to be one of the most stable wastewater treatment methods and is widely used. Combining solar interface evaporation with adsorption provides a novel and low-cost approach for the efficient removal of heavy metals and organic pollutants from industrial wastewater. This paper reviews the characteristics and application of some common wastewater treatment methods. The photothermal conversion and the conceptual design of interface evaporation combined with adsorption are introduced and the photo-thermal conversion and adsorption methods are discussed. The study provides a summary of recent studies and advancements in interfacial evaporation-coupled adsorption materials, which include hydrogels, aerogels, and biomass materials for adsorption, and carbon materials for photothermal conversion. Finally, the current challenges encountered in industrial wastewater treatment are outlined and its prospects are discussed. The aim of this review is to explore a wide range of possibilities with the interfacial evaporation-coupled adsorption method and propose a new low-cost and high-efficiency method for industrial wastewater treatment.

On the optimal texture shape with the consideration of surface roughness.

The optimal texture shape considering surface roughness is determined by solving the average Reynolds equation, selecting Jakobsson-Floberg-Olsson boundary conditions, and using a genetic algorithm. The effects of surface roughness as indicated by the combined root-mean-square (RMS), surface pattern parameter, and operating parameters on the friction coefficient, area ratio, and depth of the optimal self-defined shape and optimal dimple were studied. Results show that the friction coefficient will be significantly reduced during the shape optimization considering the effect of surface roughness. The variation laws of the optimal dimple area ratio with the combined RMS, surface pattern parameter, minimum film thickness, sliding speed and the variation law of the optimal depth of the optimal self-defined shape with surface roughness and working parameters are obtained. Finally, this study concludes that the influence of roughness parameters on the optimal dimple shape is greater than that on the optimal self-defined shape under different sliding speeds.

Air bubble removal: Wettability contrast enabled microfluidic interconnects.

The presence of air bubbles boosts the shear resistance and causes pressure fluctuation within fluid-perfused microchannels, resulting in possible cell damage and even malfunction of microfluidic devices. Eliminating air bubbles is especially challenging in microscale where the adhesive surface tension force is often dominant over other forces. Here, we present an air bubble removal strategy from a novel surface engineering perspective. A microfluidic port-to-port interconnect was fabricated by modifying the peripheral of the microfluidic ports superhydrophobic, while maintaining the inner polymer microchannels hydrophilic. Such a sharp wettability contrast enabled a preferential fluidic entrance into the easy-wetting microchannels over the non-wetting boundaries of the microfluidic ports, while simultaneously filtering out any incoming air bubbles owing to the existence of port-to-port gaps. This bubble-eliminating capability was consistently demonstrated at varying flow rates and liquid analytes. Compared to equipment-intensive techniques and porous membrane-venting strategies, our wettability contrast-governed strategy provides a simple yet effective route for eliminating air bubbles and simultaneously sealing microfluidic interconnects.

[Clinical experience of orthodontic treatment on 36 cases with congenital lower incisor missing].

OBJECTIVE: To explore the treatment plan in patients with congenital lower incisor missing. METHODS: Thirty-six patients with congenital lower incisor missing were included in the investigation. The missing location, missing quantity, malocclusion type and treatment method were analyzed. Bolton index of two groups were analyzed. The first group was congenital missing one lower incisor who treated by extracting two upper first premolars and one lower first premolar. The second group was congenital missing two lower incisors who treated by exacting two upper first premolars. RESULTS: The therapeutic effect of 36 cases were better. Overall ratio in two groups were 91.70% +/- 1.85% and 92.83% +/- 2.74%, anterior ratio were 81.69% +/- 2.12% and 85.46% +/- 2.39%, anterior tooth-size discrepancy were (2.16 +/- 0.64) mm and (4.27 +/- 1.14) mm. There were no significance difference on overall ratio in two groups (P > 0.05). There were significance difference in anterior ratio and anterior tooth-size discrepancy (P < 0.01). CONCLUSION: For patients with congenital missing one lower incisor who need extraction in upper and lower jaws, it is less affection on Bolton index that extracting one premolar at non-missing side than extracting one center incisor in mandible.