Effects of Hydrostatic Pressure Treatment of Newly Fertilized Eggs on the Ploidy Level and Karyotype of Pikeperch Sander lucioperca (Linnaeus, 1758)

We studied the effect of different magnitudes (7000 PSI (48.26 MPa), 8000 PSI (55.16 MPa), and 9000 PSI (62.05 MPa)) of hydrostatic pressure on the ploidy of pikeperch larvae. Pressure shock was applied 5 min after the fertilization of eggs at a water temperature of 14.8 ± 1 °C. A 7000 PSI pressure shock was applied for 10 or 20 min, while 8000 and 9000 PSI treatments lasted for 10 min. Each treatment with its respective control was completed in triplicate, where different females’ eggs served as a replicate. In the treatment groups exposed to 7000 PSI for 10 min, only diploid and triploid larvae were identified, while 2n/3n mosaic individuals were found after a 20-min exposure to a 7000 PSI pressure shock. The application of 8000 or 9000 PSI pressure shocks resulted in only triploid and mosaic individuals. Among larvae from eggs treated with 8000 PSI, three mosaic individuals with 2n/3n karyotype were identified (4.0 ± 6.9%), while a single (2.0 ± 3.5%) 1n/3n mosaic individual was found in the 9000 PSI-treated group. To our knowledge, this is the first report that demonstrates the induction of a haplo-triploid karyotype by hydrostatic pressure shock in teleost fish. The dominance of triploid individuals with a reasonable survival rate (36.8 ± 26.1%) after 8000 PSI shock supports the suitability of the hydrostatic pressure treatment of freshly fertilized eggs for triploid induction in pikeperch.

Study on the Unplugging Technology Through Electric Explosion Controllable Shock Wave

For the increasing well plugging in oilfield development, a new unplugging technology is presented in this paper for the downhole plugging by using high voltage pulse wave. Based on the mechanism analysis, the circuit resistance model and the empirical calculation formula of the pressure shock wave are obtained, and the influence of the same current waveform on the pressure shock wave generated by the wire explosion is preliminarily studied in laboratory experiments under different energy conditions. A corresponding unplugging evaluation test device was designed to simulate the approximate downhole reservoir conditions in the places where the shock wave occurs to test the approximate downhole stress conditions of the core, and to test the permeability changes after different shock waves acted on the core. The results show that the peak value of the pressure shock wave is proportional to the effect of well unplugging, which verifies the feasibility of the unplugging and increasing permeability technology of the electric explosion-controlled shock wave. This technology can quickly dredge the oil seepage channel, increase well permeability, thus increasing the well productivity, which has a broad application prospect and important practical significance.

The impact of the simple orifice schemes of the buffer device in boom refuelling system in the transient pressure of the pipeline

The boom refuelling system has a large refueling flow, and the refueling joint when the refueling is interrupted in an emergency will cause pressure shock and pressure pulsation. In severe cases, it will cause vibration of the pipeline system, reduce system reliability, and seriously endanger flight safety. Adding a device similar to an accumulator at the end of the pipeline where pressure shock occurs can well absorb the shock pressure. This paper uses a certain type of aircraft as a background to simulate the construction of a rigid air refueling pipeline system with a buffer device. The emphasis is on the pressure shock suppression characteristics of the buffer device. The simulation analysis of the opening parameters of the expansion cavity entrance includes the number and size of the buffer device. The impact of pressure shock performance. The results show that: the more openings and the larger the pore size, the larger the first pressure peak and the smaller the second pressure peak; while increasing the total flow area can effectively reduce the pressure shock suppression effect of the buffer device.