Given the push to strengthen European defence cooperation, the topic of whether a European strategic culture is emerging has become widely contested. Since convergence between member states is the ...key that would unlock the way to a European strategic culture, this paper examines how they perceive crucial aspects of strategic culture and in what aspects they have converged and diverged. This study selected Germany, Poland, and Ireland as cases of the EU-27 member states. It compared the three national strategic cultures in three aspects: strategic environment, cooperation patterns, and strategic goals and means, by conducting a computer-based content analysis of strategic documents and official speeches of high-level national policymakers between 2000 and 2020. This study found that despite the persistent divergence in strategic goals and means, the three countries have shown greater convergence in their perceptions of the strategic environment and that while their preferences on cooperation patterns are largely unchanged, they seem to be accepting the EU as a legitimate and favourable platform for security and defence cooperation. These findings suggest that the prospects for the emergence of a European strategic culture and further developments of the EU's Common Security and Defence Policy are both challenging and promising.
The effectiveness of four types of the baffles in suppressing pressure is experimentally investigated under a wide range of forcing frequencies. The dynamic impact pressure variations alongside the ...central line of the tank wall and the baffle response to different excitation frequencies were measured for tanks without baffles and with immersed bottom-mounted vertical baffles, vertical baffles flushing with free surface, surface-piercing bottom-mounted vertical baffles and perforated vertical baffles, respectively. The maximum impact pressure on the tank wall generally increases with decreasing the distance of the pressure sensor away from the free surface. In the frequency range from 0.4ω1 to 1.4ω1, the vertical baffle flushing with free surface is an more effective tool on reducing impact pressure comparing with the immersed bottom-mounted vertical baffle, especially near the first-mode natural frequency, and effects of the perforated vertical baffle in suppressing sloshing pressure is more significant than that of the surface-piercing bottom-mounted vertical baffle, especially in high forcing frequency region. It is found that the first-mode natural frequency of liquid-tank is altered by the vertical baffles. The experimental results show that changing flow fields and altering natural frequency may effectively suppress the impact pressure on the tank walls.
•Liquid sloshing experimental system controlled precisely by a wave-maker was developed.•Effect of the vertical baffles in suppressing sloshing pressure was studied by changing frequency.•Dynamic impact pressure on tank wall and vertical baffle were measured simultaneously.•The maximum dynamic pressure response to frequencies for tank with different vertical baffles was presented.
A series of numerical simulations were performed to investigate the influences of storage vessels shapes on sloshing dynamics under horizontal excitation by employing the open source code OpenFOAM, ...which has been extensively validated by experimental data for the sloshing flow problem. The results show that the membrane liquefied natural gas (LNG) tanks are subject to lower impact pressure than the cylindrical, rectangular and spherical tanks with the same volume of liquid and the overall tank dimensions, as the slope at the storage vessels bottom changes the flow direction of the liquid and therefore reduces the impact on the vertical wall. In the cylindrical and spherical tanks, higher impact pressure was found on the wall directly opposite to the excitation direction and the maximum impact point will shift away from the external excitation direction as the wave breaks up violently until a quasi-steady state of the sloshing wave rotating along the side wall is reached. The curved surface of the spherical tank could also help reduce the impact pressure when compared with the cylindrical tank.
•An OpenFOAM based numerical model is developed for predicting sloshing in tanks of different shapes.•The sloshing pressure in four types of vessels with the same volume of liquid is studied.•The LNG tanks were proved to be subject to lower impact pressure than the cylindrical, rectangular and spherical tanks.•Three-dimensional characteristics of sloshing in cylindrical and spherical tanks were analyzed.
A series of laboratory experiments are conducted to investigate liquid sloshing in a rectangular tank with a vertical baffle of varying elasticity under horizontal excitations. Image processing ...techniques are introduced to track baffle displacement, as well as to identify the free surface and the bubble. Dye visualization is employed to reveal the vortex behavior around the baffle. The air entrainment mechanism, including jet impinging, air cavity formation and deformation, and turbulent mixing, is analyzed. Moreover, the study investigates the effect of baffles with different stiffness on suppressing liquid sloshing across a wide range of excitation frequencies. The results show that the peak frequencies of the maximum free surface elevation-frequency curves correspond to the first natural frequency of fluid, the sub-resonance frequency, and the wet natural frequency of the elastic baffle. It is also found that the elastic baffle can effectively reduce liquid sloshing within a certain frequency range and balance the slamming impact both on the wall and the baffle, providing promising prospects for its practical applications.
The screen-affected sloshing with a wide excitation frequency including the third and the fifth mode frequencies were investigated experimentally by varying solidity ratio, slot size, location and ...slat screen number. The maximum surface elevation decreases as solidity ratio increases when frequencies are not changed obviously due to screens inside tanks. Effects of slat screen on sloshing are related to solidity ratio and frequency. One vertical screen fails in significantly suppressing sloshing excited by the third mode horizontal excitation. Two slat screens can effectively reduce sloshing excited by horizontal excitation with a relatively wide frequency range and the recommended screen positions are presented according to excitation frequencies. Sloshing reduction does not always apparently increase as screen number increases under the screen positions specified in experiments. Sloshing amplitude with two slat screens may be greater than that with one slat screen located at tank centre when frequency is near the fifth-mode or third-mode frequency depending on two screens positions. Though wave amplitudes reductions are a little more noticeable in tank with 5 mm slot size screen than those in tank with 50 mm slot size screen, wave frequency components with 5 mm slot size screen are much simpler than those with 50 mm slot size screen.
A three-dimensional (3-D) numerical model NEWTANK was developed to study viscous liquid sloshing in a tank with internal baffles of different shapes and arrangements. The numerical technique named ...virtual boundary force (VBF) method was used to model the internal baffles with complex geometries. Laboratory experiments were conducted for non-linear sloshing in a rectangular tank with and without vertical baffle. The numerical model was validated against the measured data together with other available theoretical solutions and numerical results for liquid sloshing under surge and pitch motions. Liquid sloshing in a 3D prismatic tank with different ring baffle arrangements (e.g., height, width, etc.) were further investigated under near-resonant excitations of surge and pitch motions. The fast Fourier transform (FFT) technique was used to identify the dominant response frequencies of the liquid system to external excitations. The effects of ring baffles on reducing violent liquid sloshing were investigated and discussed in detail. Finally, a demonstration of liquid sloshing in the tank under six degree-of-freedom (DOF) excitations was presented.
Legumain is required for maintenance of normal kidney homeostasis. However, its role in acute kidney injury (AKI) is still unclear. Here, we induced AKI by bilateral ischemia-reperfusion injury (IRI) ...of renal arteries or folic acid in lgmn
and lgmn
mice. We assessed serum creatinine, blood urea nitrogen, histological indexes of tubular injury, and expression of KIM-1 and NGAL. Inflammatory infiltration was evaluated by immunohistological staining of CD3 and F4/80, and expression of TNF-α, CCL-2, IL-33, and IL-1α. Ferroptosis was evaluated by Acsl4, Cox-2, reactive oxygen species (ROS) indexes H
DCFDA and DHE, MDA and glutathione peroxidase 4 (GPX4). We induced ferroptosis by hypoxia or erastin in primary mouse renal tubular epithelial cells (mRTECs). Cellular survival, Acsl4, Cox-2, LDH release, ROS, and MDA levels were measured. We analyzed the degradation of GPX4 through inhibition of proteasomes or autophagy. Lysosomal GPX4 was assessed to determine GPX4 degradation pathway. Immunoprecipitation (IP) was used to determine the interactions between legumain, GPX4, HSC70, and HSP90. For tentative treatment, RR-11a was administrated intraperitoneally to a mouse model of IRI-induced AKI. Our results showed that legumain deficiency attenuated acute tubular injury, inflammation, and ferroptosis in either IRI or folic acid-induced AKI model. Ferroptosis induced by hypoxia or erastin was dampened in lgmn
mRTECs compared with lgmn
control. Deficiency of legumain prevented chaperone-mediated autophagy of GPX4. Results of IP suggested interactions between legumain, HSC70, HSP90, and GPX4. Administration of RR-11a ameliorated ferroptosis and renal injury in the AKI model. Together, our data indicate that legumain promotes chaperone-mediated autophagy of GPX4 therefore facilitates tubular ferroptosis in AKI.
A series of numerical simulations were performed to explore the influences of filling level, excitation frequency and amplitude on liquid sloshing by using the open source Computational Fluid ...Dynamics toolbox OpenFOAM (Open Field Operation and Manipulation), which was fully validated by the experimental data. The results show that the dynamic impact pressure is proportional to the external excitation amplitude only in non-resonance frequency ranges. Pressure-frequency response curves demonstrate a transition process from a ‘soft-spring’ response to a ‘hard-spring’ response following the changes of the filling level. Such a transition process is found to be dominated by the ratio of the filling level to tank length and the critical value can be obtained. It is also found that wave breaking influences the period of sloshing wave in tanks and ultimately alters the resonance frequency from the linear theory.
Free surface of parametric sloshing will undergo unbounded motion, resulting in destabilization, if the combination of excitation frequency and amplitude is located in instable regions. In studies of ...parametric sloshing, high modes are of great concern. Our experimental results showed that dimensionless free surface elevations of parametric sloshing in a clean tank induced by high-frequency excitation were much larger than that induced by low-frequency excitation. The effectiveness of baffles in suppressing parametric sloshing and the damping mechanism of baffles were investigated and analyzed. Results showed that vertical baffles performed well in suppressing parametric sloshing. The optimal number and position of baffles to suppress sloshing depended on sloshing modes. Two noteworthy findings were revealed. One was the complete failure of one baffle in suppressing parametric sloshing of the second mode, and the other was that two baffles were less effective than one baffle in suppressing parametric sloshing of the first and the third modes. By changing the number and positions of baffles, it was concluded that the closer the position of the baffles to the nodes of sloshing modes, the more powerful the damping effect of baffles. The discovery of damping mechanism cogently explained the two noteworthy findings mentioned above.
•Participation of higher sloshing modes in a rectangular tank vertically driven are accounted.•Optimal number of baffles to suppress sloshing depends on the sloshing mode.•Optimal position of baffles to suppress sloshing depends on the distance between baffles and the nodes of sloshing mode.
Cytokinins and gibberellins (GAs) play antagonistic roles in regulating reproductive meristem activity. Cytokinins have positive effects on meristem activity and maintenance. During inflorescence ...meristem development, cytokinin biosynthesis is activated via a KNOX-mediated pathway. Increased cytokinin activity leads to higher grain number, whereas GAs negatively affect meristem activity. The GA biosynthesis genes GA20oxs are negatively regulated by KNOX proteins. KNOX proteins function as modulators, balancing cytokinin and GA activity in the meristem. However, little is known about the crosstalk among cytokinin and GA regulators together with KNOX proteins and how KNOX-mediated dynamic balancing of hormonal activity functions. Through map-based cloning of QTLs, we cloned a GA biosynthesis gene, Grain Number per Panicle1 (GNP1), which encodes rice GA20ox1. The grain number and yield of NIL-GNP1TQ were significantly higher than those of isogenic control (Lemont). Sequence variations in its promoter region increased the levels of GNP1 transcripts, which were enriched in the apical regions of inflorescence meristems in NIL-GNP1TQ. We propose that cytokinin activity increased due to a KNOX-mediated transcriptional feedback loop resulting from the higher GNP1 transcript levels, in turn leading to increased expression of the GA catabolism genes GA2oxs and reduced GA1 and GA3 accumulation. This rebalancing process increased cytokinin activity, thereby increasing grain number and grain yield in rice. These findings uncover important, novel roles of GAs in rice florescence meristem development and provide new insights into the crosstalk between cytokinin and GA underlying development process.
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