Optimal Dietary Protein Level for the White Shrimp (Litopenaeus vannamei ) in Low Salinity Water

In order to find the optimal dietary protein level for Litopenaeus vannamei in low salinity water, isolipid and isocaloric diets with different protein levels (25%, 30%, 35%, 40% and 45%) were tested to feed L. vannamei juveniles (mean weight 0.31 ± 0.02 g) for 56 days in salinity 2 g/L water. The results showed that: (1) as the dietary protein level increased, the final body weight, weight gain and specific growth rate increased at first and then decreased. In the 35% protein level group, significantly better results were obtained as compared to other groups (P<0.05). Through quadratic regression analysis of dietary protein level and weight gain and specific growth rate, we found that shrimps had the highest weight gain when dietary protein level was between 33.51%–34.35%; (2) as the dietary protein level increased, the shrimp moisture content decreased and the protein content increased while lipid and ash content did not significantly change; (3) as the dietary protein level increased, the activity of trypsin increased at first and then decreased, and the 35% protein level group had the highest trypsin activity, significantly higher than other groups (P<0.05). There were no significant differences in lipase or amylase activity

Research on Working Condition Diagnosis of Submersible Screw Pump

As the development of each oil field enters the middle and late stage, sand production, wax deposition and the continuous increase of well depth, electric submersible screw pump wells frequently break down, and hidden troubles of equipment can not be found in time, which makes oil wells produce with faults. It increases the wear and tear of equipment, seriously affects the production of oil wells, and causes unnecessary economic losses. Therefore, improving the accuracy of the working condition diagnosis of the electric submersible screw pump production system plays a vital role in improving the overall management level of the electric submersible screw pump well. This can not only enhance the managers’ correct understanding of this kind of oil well system, but also comprehensively monitor the working state of the well. It can find the fault as soon as possible, analyze the cause of the fault, and avoid the accident by adjusting the production parameters, so that the downhole screw pump can work safely, reliably and effectively, and maximize the maintenance free period and economic benefits of the electric submersible screw pump well

Toward smartphone applications for geoparksinformation and interpretation systems in China

Geopark information and interpretation systemsare both necessary infrastructure in geopark planning andconstruction program, and they are also essential for geoeducationand geoconservation in geopark tourism. Thecurrent state and development of information and interpretationsystems in China’s geoparks were presented andanalyzed in this paper. Statistics showed that fewer thanhalf of geoparks run websites, and less than that amountmaintained database, and less than one percent of allInternet/smartphone applications were used for geoparktourism. The results of our analysis indicated that smartphoneapplications in geopark information and interpretationsystems would provide benefits such as acceleratedgeopark science popularization and education and facilitatedinteractive communication between geoparks andtourists

Dual effect of ZrO2 on phase separation and crystallization in Li2O-Al2O3-SiO2-P2O5 glasses

International audienceZrO2 is an effective nucleation agent for low-expansion lithium-aluminum silicate (LAS) glass-ceramic (GC) with high Al2O3 content. However, the effect of ZrO2 is still not fully understood in LAS glasses with low contents of Al2O3 and P2O5. In this work, the effect of ZrO2 on the phase separation and crystallization of Li2O-Al2O3-SiO2-P2O5 glasses were investigated. The results revealed that ZrO2 significantly increased T-g and the crystallization temperature of Li2SiO3 and Li2Si2O5 crystals. Li3PO4 crystals precipitated preferentially in the glass containing 3.6-mol% ZrO2, wherein Zr was stable in the network and no precipitation of ZrO2 nanocrystals was observed. Moreover, the separation of phosphate-rich phases in the as-quenched glasses increased with the addition of ZrO2. The findings of the study revealed a dual role of ZrO2. First, ZrO2 acted as a glass network former rather than a nucleation agent, increasing glass viscosity and the nucleation barrier of Li2SiO3 through its strong network connectivity. Second, as Zr preferentially combined with non-bridging oxygen to form Si-O-Zr linkages, a sufficient amount of charge-balancing Li+ ions existed in the network, which promoted the separation of phosphate-rich phases. It indicated that the incorporation of ZrO2 contributes to the activation of the nucleation role of P2O5, thus contributing to the formation of nanocrystals and fine microstructure of GCs