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Dredging Equipment
Published in Jan van ‘t Hoff, Art Nooy van der Kolff, Hydraulic Fill Manual, 2012
Jan van ‘t Hoff, Art Nooy van der Kolff
Booster pump stations can be employed to increase the pumping capacity. If the situation allows this, preference should be given to hopper dredgers or barges since the employment of booster pump stations usually has a significant impact on the dredging costs.
Effect of the pressurized duration on improving dredged slurry with air booster vacuum preloading
Published in Marine Georesources & Geotechnology, 2020
Shanwei Ke, Peng Wang, Xiuqing Hu, Xueyue Geng, Jun Hai, Jinqiang Jin, Ziwu Jiang, Qiang Ye, Zhijian Chen
The vacuum pressure in the pressurization tests remained stable before the booster system was activated but experienced large fluctuations after the booster system was activated. The vacuum pressure recovered after the booster pump was closed. The pressure fluctuations of pressurization tests A–D were approximately 10, 15, 20, and 22 kPa, respectively. This was mainly because, as the pressurized duration increased, the continuous action of the pressurized air produced more cracks in the soil. More positive pressure was generated by the intermittent injection of compressed air to neutralize the negative pressure, which reduced the vacuum pressure. With long-term pressurization, the soil cracks between the pressurizing pipe and PVD could fracture completely, which would cause the positive pressure of 20 kPa generated by the booster pump to be totally neutralized by the negative pressure, as shown in Figure 5(d). However, the same reduction in the vacuum pressure of 20 kPa is not shown in Figure 5(e), this may be because the operating power of the booster pump occasionally increased, which increased the positive pressure during the long pressurization period for Group D.
Effect of pressurization positions on the consolidation of dredged slurry in air-booster vacuum preloading method
Published in Marine Georesources & Geotechnology, 2020
Zhiwei Xie, Jun Wang, Hongtao Fu, Yuanqiang Cai, Hu Xiuqing, Yin Cai, Yan Zhang, Xiaohua Ma, Haisheng Jin
When the pressurizing system activated, the vacuum pressure of T2, T3, T4 and T5 all began constant fluctuation in the soil and PVDs. The main reason was that the positive pressure by booster pump will offset the part of negative pressure by vacuum pump. It was worth noting that the fluctuation range of the vacuum pressure in the soil was larger than that in PVDs (shown in Figure 5) due to the seepage velocity of vacuum pressure in soil was much lower than that in PVD. Moreover, vacuum pressure fluctuations of T2 and T3 in bottom are significantly larger than T4 and T5 whereas its middle parts are far less than the two later ones. Among them, the detail fluctuation figures of T3 and T5 were shown in Figure 5, which that the main influence area of different pressurizing position was different through the analysis of the fluctuation range in the four parts (1, 2, 3 and 4). Besides, the relevant datum of the two group tests (T2 and T3, T4 and T5) indicated that the booster pipeline type has little effect on the vacuum pressure. These results also clearly indicate that pressurization effect could weaken the stability of vacuum pressure, but have a further potential to accelerate soil consolidation.
Optical emission generated by particle impact during aerosol deposition of alumina films
Published in Journal of Asian Ceramic Societies, 2022
Yasuhito Matsubayashi, Tsuyohito Ito, Kentaro Shinoda, Kazuo Terashima, Jun Akedo
The schematic of the experimental setup is shown in Figure 1. The deposition system was the same as in previous reports [1,4]. The main chamber was evacuated by a mechanical booster pump and a rotary pump, whose base pressure was 40 Pa. In a mechanically vibrated aerosol chamber, single-crystal α–alumina microparticles (average diameter 0.38 μm, AA-03, Sumitomo Chemical Co., Ltd.) were dispersed as an aerosol by a gas flow (He, N2, and Ar; flow rate: 1–20 standard liter per minute [SLM]) and accelerated toward a borosilicate glass substrate in the main chamber by a nozzle (orifice of 0.4 × 10 mm). The alumina powder consisted of single crystals grown by chemical vapor deposition and showed a low AD deposition efficiency [35]. However, this powder had a narrow size distribution with a single peak, making it suitable for spectroscopic analysis. The pressures inside the main chamber increased to 2000 Pa with the gas flow, according to the flow rate. The gap between the nozzle and the substrate was 5 mm during spectroscopic measurements. The gap was widened to 20 mm while the photographs were taken to reveal the spatial distribution of the optical emission. These experimental conditions are typical of film fabrication with AD [1,2]. The light emitted from the gap was collected by optical lenses through the SiO2 glass window and analyzed by a spectrometer (Glacier X, B&W TEK Inc.). The spectrum of the N2 second positive system (2PS), emitted by the transitions from the C 3Πu state to the B 3Πg state, was analyzed following the literature [36].