Superwicking Functionality of Femtosecond Laser Textured Aluminum at High Temperatures

An advanced superwicking aluminum material based on a microgroove surface structure textured with both laser-induced periodic surface structures and fine microholes was produced by direct femtosecond laser nano/microstructuring technology. The created material demonstrates excellent wicking performance in a temperature range of 23 to 120 °C. The experiments on wicking dynamics show a record-high velocity of water spreading that achieves about 450 mm/s at 23 °C and 320 mm/s at 120 °C when the spreading water undergoes intensive boiling. The lifetime of classic Washburn capillary flow dynamics shortens as the temperature increases up to 80 °C. The effects of evaporation and boiling on water spreading become significant above 80 °C, resulting in vanishing of Washburn’s dynamics. Both the inertial and visco-inertial flow regimes are insignificantly affected by evaporation at temperatures below the boiling point of water. The boiling effect on the inertial regime is small at 120 °C; however, its effect on the visco-inertial regime is essential. The created material with effective wicking performance under water boiling conditions can find applications in Maisotsenko cycle (M-cycle) high-temperature heat/mass exchangers for enhancing power generation efficiency that is an important factor in reducing CO2 emissions and mitigation of the global climate change.

The Effect of G-C3N4 on Bacterial Community in Sediment of Xiang River Under Tetracycline Pressure

As photocatalysts applied more and more often to treat pollutants by photocatalytic reactions, they may enter the environment via water spreading. Although there are some investigations about their influence on different organisms, little is known about its impact on the ecological microenvironment. To understand how photocatalysts effect sediment ecological microenvironment in the process of pollution remediation, the impact of typical photocatalyst g-C3N4 (Graphitic carbon nitride) on rivered sediment community polluted by typical antibiotic tetracycline (TC) was investigated. The sediment samples were exposed to different concentrations of TC, g-C3N4 or TC/g-C3N4 (exposed to 60, 120, 180 mg/L TC, or 25, 75, 125 mg/kg g-C3N4, or 25, 75, 125 mg/kg g-C3N4 plus 60, 120, 180 mg/L TC, respectively), and sediment bacterial community were analyzed by Illumina sequencing. The results indicated that the dominant bacterial phyla in the samples were Acidobacteriota, Proteobacteria, Actinobacteriota, Chloroflexi. The diversity and richness of microorganisms in riverbed sediment were increased a little bit by g-C3N4 with different concentrations, which reached the highest value when exposed to 75 mg/kg g-C3N4. g-C3N4 lightly increased the percentage of relative abundance of Cyanobacteria. The bacterial communities’ structure of the samples treated with TC, g-C3N4 or TC/g-C3N4 were distinguishable. g-C3N4 alone had little effect on microbial structure, while TC/g-C3N4 had medium influence and TC had great impact on it. Under TC stress, g-C3N4 slowed down the growth of Cyanobacteria to some extent and restored the changes of bacterial community structure caused by TC, and reduced the residual TC in water body, thus eliminating the side effects of TC. The result shown that g-C3N4 could significantly reduce the residue of TC in riverbed sediment, without affecting the microbial ecology in the environment.

Effect of jade nanoparticle content and twist of cool-touch polyester filaments on comfort performance of knitted fabrics

Cool-touch polyester knitted fabrics with excellent thermal-wet and cooling comfort ability are desired for summer and sports clothing. Jade nanoparticle content and twist of filaments have significant effects on comfort-related properties. In this work, the effects of jade content and twist level of two types of cross-section polyester filament on fabric comfort-related properties were investigated in detail. Filaments were prepared and further knitted to fabric samples. The physical performance of polyester filaments, the thermal-wet transfer properties and dynamic cooling property of their fabrics were measured and analyzed. It was found that the jade nanoparticles mainly affected thermal transfer property of fabrics, and the best thermal transfer was exhibited by fabric with 7% cool-touch PET chip. With the increase of twist level, air permeability, water spreading and drying performance improved but thermal transfer ability decreased, and lower twist level of yarns was beneficial for achieving real moisture cooling properties. These results showed a major advance in developing thermal-wet comfort knitted fabrics using cool-touch filaments with appropriate twist level.

Water spreading weirs altering flood, nutrient distribution and crop productivity in upstream–downstream settings in dry lowlands of Afar, Ethiopia

Afar in Ethiopia is a drought prone area characterized by low rainfall, high temperature and suffering from flash flood emerging from adjacent mountains. We introduced a flood barrier, water spreading weirs (WSWs) in 2015 to convert floods to a productive use and assessed its effect in 2016 and 2017. WSWs resulted in deposition of sediments where sand deposition was higher in the upside of upstream weir whereas silt and clay deposition was prominent at the central location between the two weirs. There was a moisture gradient across farming fields with volumetric water content (VWC) at 20 cm depth varying between 10 and 22% depending on the relative position/distance of fields from the WSWs, consequently, effecting significant difference in yield between fields. There was a positive relationship between VWC made available by WSWs at planting and the yield (P < 0.001, r = 0.76) and biomass productivity (P < 0.005, r = 0.46). WSWs created differing farming zone following soil moisture regime, affecting grain and biomass yield. In good potential zones with high moisture content, the WSW-based farming enabled to produce up to 5 and 15 t ha−1 yr−1 of maize grain and biomass, respectively, while in low potential zones there was a complete crop grain failure. The system enabled pastoralists to produce huge amount of biomass and grain during Belg (short) and Meher (long) growing seasons that was stored and utilized during succeeding dry periods. Furthermore, the practice ensured a visible recovery of degraded rangelands. This was evident from the filling up of the riverbed as well as the two WSW wings with 1 m high and about 450 m length each with fertile sediment from Belg and Meher seasons of 2016 and 2017. Hence, future studies should analyze the sustainability and the potential of flood-based development at large scale.