Scour Protection of Submarine Pipelines Using Ionic Soil Stabilizer Solidified Soil

A novel scour protection approach for pipeline using the Ionic Soil Stabilizer (ISS) solidified soil was proposed in this study. The ISS-solidified slurry can be poured adjacent to the pipeline immediately after it was placed, or in the growing scour holes. In the present study, the first type was utilized as the scour protection layer around the pipeline. A series of laboratory flume tests were conducted to validate the protective capacity of ISS-solidified slurry for the pipeline in waves and combined waves and current. Then, the scanning electron microscope (SEM) tests and pore size tests were carried out, respectively, to investigate the mechanism of ISS-solidified slurry for scour protection around the pipeline. Finally, the effects of the ISS-solidified layer for liquefaction stability of non-cohesive subsoil were evaluated. The results indicated that the ISS-solidified slurry is a reliable, economic approach for scour protection around pipelines in the ocean environment. It is noteworthy that if a non-cohesive soil layer underlies the ISS-solidified slurry, it is vulnerable to suffer accumulated liquefaction due to the dense crust structure of the ISS-solidified layer, so the adverse effects for accumulated liquefaction should be considered carefully due to the set of the ISS-solidified layer.

A scalable, ecofriendly, and cost-effective lithium metal protection layer from a Post-it note

A low-cost, ecofriendly, and scalable paper-derived protective layer is designed to achieve excellent electrochemical performance.

Microstructure and Phase Investigation of Sn-58Bi-xCu Lead-Free Solder After Immersion in Sodium Chloride Solution

The changes in microstructure and phase of tin-bismuth-copper (Sn-58Bi-xCu) were investigated after immersion in 3.5 wt. % sodium chloride (NaCl) at variations of Cu micro-alloying at 0.25, 0.50, 0.75, 1.00 and 1.25 wt. %. The morphological observation revealed that the long crystal grains of the Cu-rich phase were produced as the amount of Cu increased. The phase analysis shows that at 0.5 wt. % Cu additions, the intermetallic compound od Cu6Sn5 began to form and dominate the microstructure. After immersion in NaCl, a porous structure was seen covering the surface of the ternary solder, indicating the formation of a defective corrosion protection layer. The predominance of Cu6Sn5 is believed to boost the galvanic corrosion coupling potential of the ternary solder. As a result, the more electrochemically reactive phase was pushed to be eliminated during immersion in 3.5 wt.% NaCl solution. Thus the black spots were formed. The presence of Cu6Sn5 was seen to be detrimental to the electrochemical performance of Sn-58Bi-xCu.