A Method for Solving Percolation Overflow Boundary Based on Maximum of Horizontal Energy Loss Rate

The determination of overflow boundary is a prerequisite for the accurate solution of the seepage field by the finite element method. In this paper, a method for solving overflow boundary according to the maximum value of horizontal energy loss rate is proposed, which based on the analysis of the physical meaning of functional and the water head distribution of seepage field under different overflow boundaries. This method considers that the overflow boundary that makes the horizontal energy loss rate reach the maximum value is the real boundary overflow. Compared with the previous iterative computation method of overflow point and free surface, the method of solving overflow boundary based on the maximum horizontal energy loss rate does not need iteration, so the problem of non-convergence does not exist. The relative error of the overflow points is only 1.54% and 0.98% by calculating the two-dimensional model of the glycerol test and the three-dimensional model of the electric stimulation test, respectively. Compared with the overflow boundary calculated by the node virtual flow method, improved cut-off negative pressure method, initial flow method, and improved discarding element method, this method has a higher accuracy.

Neutrino energy-loss rate in 331β model

We evaluate the stellar energy-loss rates [Formula: see text] due to the production of neutrino pair in 3-3-1 models. The energy loss rate [Formula: see text] is evaluated for different values of [Formula: see text] in which [Formula: see text] is a parameter used to define the charge operator in the 331 models. We show that the contribution of dipole moment to the energy loss rate is small compared to the contribution of new natural gauge boson [Formula: see text]. The correction [Formula: see text] compared with that of Standard Model is evaluated and do not exceed 14% and is highest with [Formula: see text]. Of all the evaluated models, model with [Formula: see text] give a relative large [Formula: see text] correction for the mass of [Formula: see text][Formula: see text] GeV. This mass range is within the searching range for [Formula: see text] boson at LHC.

Segmental assessment of blood flow efficiency in the total cavopulmonary connection using 4D flow MRI: vortical flow is associated with increased viscous energy loss

Objectives To study flow-related energetics in multiple anatomical segments of the total cavopulmonary connection (TCPC) in Fontan patients from 4D flow MRI, and to study the relationship between adverse flow patterns and segment-specific energetics. Methods Twenty-six extracardiac Fontan patients underwent 4D flow MRI of the TCPC. A segmentation of the TCPC was automatically divided into 5 anatomical segments (conduit, superior vena cava, right/left pulmonary artery (PA) and the Fontan confluence). The presence of vortical flow in the PAs or Fontan confluence was qualitatively scored. Kinetic energy, viscous energy loss and vorticity were calculated from the 4D flow MRI velocity field and normalized for segment length and/or inflow. Energetics were compared between segments and the relationship between vortical flow and segment cross-sectional area (CSA) with segment-specific energetics was determined. Results Vortical flow in the LPA (n = 6) and Fontan confluence (n = 12) were associated with significantly higher vorticity (p = 0.001 and p = 0.015, respectively) and viscous energy loss rate (p = 0.046 and p = 0.04, respectively) compared to patients without vortical flow. The LPA and conduit segments showed the highest kinetic energy and viscous energy loss rate, while most favorable energetics were observed in the superior vena cava. Conduit CSA inversely correlated with kinetic energy (r= -0.614, p = 0.019) and viscous energy loss rate (r= -0.652, p = 0.011). Conclusions Vortical flow in the Fontan confluence and LPA associated with significantly increased viscous energy loss rate. 4D flow MRI derived energetics may be used as a screening tool for direct, MRI-based assessment of flow efficiency in the TCPC.

Analysis of Rockfall Hazards Stopping position and Energy dissipation Based on Orthogonal experiment

Many factors affect the movement of rockfall. Thus, this study explored the influence of rockfall shape, slope angle, angular velocity, slope hardness, rockfall mass, and slope surface roughness on the stopping position and potential energy loss rate based on an orthogonal experiment. To study the key factors affecting the movement of rockfall, 2500 sets of orthogonal tests were carried out by using ROCFALL 8.0 (ROCSCIENCE) numerical simulation program. SPSS19.0 software was used to perform importance analysis and correlation analysis on the test results. The analysis results show that rockfall shape has the greatest influence on the stopping distance. There is a significant positive linear correlation between the number of rockfall edges and the stopping distance of rockfall on the asphalt road. The slope angle has the greatest influence on the potential energy loss rate, and there is a significant negative linear correlation between the slope angle and the potential energy loss rate. In the case of a low angle slope, the stopping position of rockfall is more concentrated. Therefore, in the process of mountain engineering construction, more attention should be paid to the influence of rockfall shape and slope angle on rockfall hazard protection.

Jiamusi pulsar observations

Aims. Most pulsar nulling observations have been conducted at frequencies lower than 1400 MHz. We aim to understand the nulling behaviors of pulsars at relatively high frequencies, and to decipher whether or not nulling is caused by a global change in the pulsar magnetosphere. Methods. We used the Jiamusi 66 m telescope to observe 20 bright pulsars at 2250 MHz with unprecedented lengths of time. We estimated the nulling fractions of these pulsars, and identified the null and emission states of the pulses. We also calculated the nulling degrees and scales of the emission-null pairs to describe the distributions of emission and null lengths. Results. Three pulsars, PSRs J0248+6021, J0543+2329, and J1844+00, are found to null for the first time. The details of null-to-emission and emission-to-null transitions within the pulse window are observed for the first time for PSR J1509+5531, which is a low-probability event. A complete cycle of long nulls with timescales of hours is observed for PSR J1709−1640. For most of these pulsars, the K-S tests of nulling degrees and nulling scales reject the hypothesis that null and emission are caused by random processes at high significance levels. Emission-null sequences of some pulsars exhibit quasi-periodic, low-frequency or featureless modulations, which might be related to different origins. During transitions between emission and null states, pulse intensities have diverse tendencies for variation. Significant correlations are found between respectively nulling fraction, nulling cadence, and nulling scale and the energy loss rate of the pulsars. Combined with the nulling fractions reported in the literature for 146 nulling pulsars, we find that statistically large nulling fractions are more tightly related to pulsar period than to characteristic age or energy-loss rate.