ALBERT

Description: We study the large solar energetic particle (SEP) events that were detected by GOES in the 〉 10 MeV energy channel during December 2006 to March 2014. We derive and compare solar particle release (SPR) times for the 0.25–10.4 MeV electrons and 10–100 MeV protons for the 28 SEP events. In the study, the electron SPR times are derived with the time-shifting analysis (TSA) and the proton SPR times are derived using both the TSA and the velocity dispersion analysis (VDA). Electron anisotropies are computed to evaluate the amount of scattering for the events under study. Our main results include: 1) near-relativistic electrons and high-energy protons are released at the same time within 8 min for most (16 of 23) SEP events. 2)There exists a good correlation between electron and proton acceleration, peak intensity and intensity time profiles. 3) The TSA SPR times for 90.5 MeV and 57.4 MeV protons have maximum errors of 6 min and 10 min compared to the proton VDA release times, respectively, while the maximum error for 15.4 MeV protons can reach to 32 min. 4) For 7 low-intensity events of the 23, large delays occurred between 6.5 MeV electrons and 90.5 MeV protons relative to 0.5 MeV electrons. Whether these delays are due to times needed for the evolving shock to be strengthened or due to particle transport effects remains unsolved.

Description: The moderate and intense geomagnetic storms are identified for the first 77 months of solar cycle 23 and 24. The solar sources responsible for the moderate geomagnetic storms are indentified during the same epoch for both the cycles. Solar cycle 24 has shown nearly 80 % reduction in the occurrence of intense storms where as it is only 40 % in case of moderate storms when compared to previous cycle. The solar and interplanetary characteristics of the moderate storms driven by CME are compared for solar cycle 23 and 24 in order to see reduction in geoeffectiveness has anything to do with the occurrence of moderate storm. Though there is reduction in the occurrence of moderate storms, the Dst distribution does not show much difference. Similarly the solar source parameters like CME speed, mass and width did not show any significant variation in the average values as well as the distribution. The correlation between VBz and Dst is determined and it is found to be moderate with value of 0.68 for cycle 23 and 0.61 for cycle 24. The magnetospheric energy flux parameter epsilon (Ɛ) is estimated during the main phase of all moderate storms during solar cycles 23 and 24. The energy transfer decreased in solar cycle 24 when compared to cycle 23. These results are significantly different when all geomagnetic storms are taken in to consideration for both the solar cycles.

Description: Hydrodynamics characteristics like flow pattern, shear rate distribution, power consumption, axial pumping capacity, mixing time, and mixing efficiency of an ellipse gate (EG) impeller were investigated by experimental and numerical methods. The numerical simulation results were validated by experimental data of power consumption and mixing time. Results indicate that the axial pumping number of the EG impeller is larger than that of any other reported large-scale impeller under laminar regime, and that the shear rate formed by this impeller is less sensitive to Reynolds numbers. In-depth analysis reveals the different function of each part of the EG impeller under different flow regimes. This impeller provides an almost similar mixing efficiency like the double-helical ribbon impeller under laminar regime, but much higher mixing efficiency both under transitional and turbulent flow regimes. An ellipse gate impeller was designed for fermentation processes with varying fluid viscosities in order to cover turbulent to transient or even laminar flow regimes in a reactor. Hydrodynamics characteristics were investigated by experimental and numerical methods, indicating excellent mixing properties of this impeller in a wide range of Reynolds numbers.

Description: We report on a study that compares the properties of magnetic clouds (MCs) during the first 73 months of solar cycles 23 and 24 in order to understand the weak geomagnetic activity in cycle 24. We find that the number of MCs did not decline in cycle 24, although the average sunspot number is known to have declined by ~40%. Despite the large number of MCs, their geoeffectiveness in cycle 24 was very low. The average Dst index in the sheath and cloud portions in cycle 24 was −33 nT and −23 nT, compared to −66 nT and −55 nT, respectively in cycle 23. One of the key outcomes of this investigation is that the reduction in the strength of geomagnetic storms as measured by the Dst index is a direct consequence of the reduction in the factor VB z (the product of the MC speed and the out-of-the-ecliptic component of the MC magnetic field). The reduction in MC-to-ambient total pressure in cycle 24 is compensated for by the reduction in the mean MC speed, resulting in the constancy of the dimensionless expansion rate at 1 AU. However, the MC size in cycle 24 was significantly smaller, which can be traced to the anomalous expansion of coronal mass ejections near the Sun reported by Gopalswamy et al. (2014a). One of the consequences of the anomalous expansion seems to be the larger heliocentric distance where the pressure balance between the CME flux ropes and the ambient medium occurs in cycle 24.

Description: We study the interaction between coronal holes (CHs) and coronal mass ejections (CMEs) using a resultant force exerted by all the coronal holes present on the disk and is defined as the coronal hole influence parameter (CHIP). The CHIP magnitude for each CH depends on the CH area, the distance between the CH centroid and the eruption region, and the average magnetic field within the CH at the photospheric level. The CHIP direction for each CH points from the CH centroid to the eruption region. We focus on Solar Cycle 23 CMEs originating from the disk center of the Sun (central meridian distance ≤15°) and resulting in magnetic clouds (MCs) and non-MCs in the solar wind. The CHIP is found to be the smallest during the rise phase for MCs and non-MCs. The maximum phase has the largest CHIP value (2.9 G) for non-MCs. The CHIP is the largest (5.8 G) for driverless (DL) shocks, which are shocks at 1 AU with no discernible MC or non-MC. These results suggest that the behavior of non-MCs is similar to that of the DL shocks and different from that of MCs. In other words, the CHs may deflect the CMEs away from the Sun-Earth line and force them to behave like limb CMEs with DL shocks. This finding supports the idea that all CMEs may be flux ropes if viewed from an appropriate vantage point.

Description: We investigate the variability in the occurrence of energetic storm particle (ESP) events associated with shocks driven by coronal mass ejections (CMEs). The interplanetary shocks were detected during the period from 1996 to 2006. First, we analyze the CME properties near the Sun. The CMEs with an ESP-producing shock are faster ($\langle$VCME$\rangle$ = 1088 km/s) than those driving shocks without an ESP event ($\langle$VCME$\rangle$ = 771 km/s) and have a larger fraction of halo CMEs (67% versus 38%). The Alfvénic Mach numbers of shocks with an ESP event are on average 1.6 times higher than those of shocks without. We also contrast the ESP event properties and frequency in shocks with and without a type II radio burst by dividing the shocks into radio-loud (RL) and radio-quiet (RQ) shocks, respectively. The shocks seem to be organized into a decreasing sequence by the energy content of the CMEs: RL shocks with an ESP event are driven by the most energetic CMEs, followed by RL shocks without an ESP event, then RQ shocks with and without an ESP event. The ESP events occur more often in RL shocks than in RQ shocks: 52% of RL shocks and only ∼33% of RQ shocks produced an ESP event at proton energies above 1.8 MeV; in the keV energy range the ESP frequencies are 80% and 65%, respectively. Electron ESP events were detected in 19% of RQ shocks and 39% of RL shocks. In addition, we find that (1) ESP events in RQ shocks are less intense than those in RL shocks; (2) RQ shocks with ESP events are predominately quasi-perpendicular shocks; (3) their solar sources are located slightly to the east of the central meridian; and (4) ESP event sizes show a modest positive correlation with the CME and shock speeds. The observation that RL shocks tend to produce more frequently ESP events with larger particle flux increases than RQ shocks emphasizes the importance of type II bursts in identifying solar events prone to producing high particle fluxes in the near-Earth space. However, the trend is not definitive. If there is no type II emission, an ESP event is less likely but not absent. The variability in the probability and size of ESP events most likely reflects differences in the shock formation in the low corona and changes in the properties of the shocks as they propagate through interplanetary space and the escape efficiency of accelerated particles from the shock front.

Description: Siphon water conveyance is a commonly used way to transport water in high efficiency, and its core equipment is the submerged rectifying device at the entrance. Due to the complex structure inside the device, the local resistance loss is too high, which has a certain impact on the water delivery efficiency. By taking the single conical diffuser inside the siphon rectifying device as the research object, analyzing the mesh generation and the simulation strategy. Of which the target is reducing the resistance loss. Then the optimal plan is y w =10μm, N=20, R=1.3, using k-ε standard. And the analyzing of the head loss in each part of the conical diffuser is based on the simulation results. The obtained head loss of the diffuse part account for 40%-50% of the total loss. The parametric analysis of the conical diffuser structure is carried out for the diffuse part. Through the orthogonal design and the result analyzed, the optimal structural scheme is L1=36mm, L2=74mm, D1=17...

Description: In order to reveal the influence of the blade outlet angle on the structural dynamic characteristics of chemical process pump, a chemical process centrifugal pump with high specific speed was selected to be researched, and 4 impellers with different blade outlet angle were redesigned based on the prototype pump, which ensuring that the other geometrical parameters unchanged. The blade outlet angle designed are 27°, 37°, and 47°, referring to the original impeller whose blade outlet angle was 22°. Then, the numerical calculation was applied for each scheme under designed condition based on the bidirectional coupling fluid- structure interaction (FSI) simulations. Through simulation, the head after the fluid-solid coupling was lower than before, but the error was reduced. Comparing the distribution of equivalent stress at intersection boundary, it shows that the places from 0.6 times to 0.8 times at the outlet of the intersection boundary of stress side and shroud were greatly aff...

Description: QUAL2K is a comprehensive longitudinal one-dimension steady-state water quality model, which considers the effect on dissolved oxygen (DO) through nitrogen circulation, algae growth and sediment oxidation process. And this model integrated hydrological model and temperature model, so it is widely adopted in the overseas. Because of its complexity and multiple parameters, the application of this model is restricted in China. Parameters optimization is inevitable in the usage of the water quality model. The modified Morris screening method is used and DO is selected as study index to proceed sensitivity analysis and further optimize related parameters. The high sensitive parameters, sensitive parameters and low sensitive parameters are determined.

Description: In this paper, we use the finite element software MSC·PATRAN and MSC·NASTRAN to establish the FEM model. Then we analyze the racking condition strength under the conditions of inclined shipping, and discuss the stress of the hull structure, the distribution of the hot spot and the deformation of the deflection under the flexible design concept. Some general conclusions under the design concept are obtained, which will be expected to contribute to the development of the design concept of the whole ship flexible structure.