Journal of Civil and Environmental Engineering

In refractive surgery, solid-state lasers emerged as an alternative to excimer systems at the beginning of the 2000s. Solid-state laser systems were capable of producing excellent clinical outcomes despite some of the limitations imposed by technology at the time. The clinical outcomes of five eyes treated by a new solid-state laser system in three patients are reported in this prospective case series. Prior to surgery, corneal top andtomography, aerometry and confocal microscopy were used to examine the patients. After undergoing a refractive treatment with the solid-state ablation laser and a femtosecond LASIK procedure with the Ziemer LDV Z8, each patient was followed up for up to a year. None of the operated subjects showed any higher-order or spherical aberrations when the aspheric optimized profiles were used. During the follow-up, no BCVA lines were removed from any of the eyes. The safety index for patient 1 was 5 six months after surgery, while it was equal to 1 for patients.

Over 90% of the world's natural gas hydrate (NGH) is contained in fine-grained reservoirs. These reservoirs can be found all over the world. However, conventional methods make it difficult to economically and environmentally exploit this kind of NGH reservoir. Because the production process does not depend on mass and heat transfer within the formations, water-jet cutting is a method for mining such hydrate reservoirs that is both effective and good for the environment. The purpose of this work was to clarify the erosion performance of marine hydrate-bearing sediment (HBS) impacted by water jets through a series of physical experiments. According to the findings, water jet vertical erosion of HBS is severely hampered by the accumulation of sediment and hydrate particles at the bottom of the erosion hole. The optimal jet distance for a given jet flow rate is between 4 and 28 millimetres. Additionally, the erosion of the hole's top is significantly affected by the upwelling flow of solid particles. Erosion holes take on the shapes of a gourd and a bamboo in reservoirs with high hydrate saturation (60–80%) and low hydrate saturation (20–40%), respectively. In addition, jet distance and hydrate saturation are less affected by jet flow rate variation than volume erosion efficiency and depth erosion efficiency.