In this paper the nonlinear behavior of supported pipes conveying pulsating fluid is examined in the vicinity of subharmonic and combination resonances. The method of averaging is used to yield a set of autonomous equations. The autonomous, averaged equations are then examined to determine the bifurcation behavior of the system. It is found that for subharmonic resonance, the averaged equation loses its stability through a simple or double zero bifurcation depending on the damping parameter; whereas, for combination resonance, the averaged system loses its stability through a Hopf bifurcation giving rise to a periodic solution. Explicit results for the stability boundaries and bifurcation paths are obtained. Numerical results are plotted for pinned-pinned pipse.

Bifurcation behavior of nonlinear pipes conveying pulsating flow

Nonlinear dynamics of fluid-conveying composite pipes subjected to time-varying axial tension in sub- and super-critical regimes

Pipes conveying fluid: A fertile dynamics problem

Dynamic modeling and experimental study of a complex fluid-conveying pipeline system with series and parallel structures

Nonlinear parametric vibration of spinning pipes conveying fluid with varying spinning speed and flow velocity

Objective To investigate the value of gray-scale ultrasound (US) image histogram in the differential diagnosis between small (≤2.00 cm), oval, or round triple negative breast invasive ductal carcinoma (TN-IDC) and fibroadenoma (FA). Methods Fifty-five cases of triple negative breast invasive ductal carcinoma (TN-IDC group) and 57 cases of breast fibroadenoma (FA group) confirmed by pathology in Hubei cancer hospital from September 2017 to September 2021 were analyzed retrospectively. The gray-scale US images were analyzed by histogram analysis method, from which some parameters (including mean, variance, skewness, kurtosis and 1st, 10th, 50th, 90th and 99th percentile) can be obtained. Intraclass correlation coefficient (ICC) was used to evaluate the inter observer reliability of histogram parameters. Histogram parameters between the TN-IDC and FA groups were compared using independent Student’s t-test or Mann-Whitney U-test, respectively. In addition, the receiver operating characteristic (ROC) curve analysis was used for the significant parameters to calculate the differential diagnosis efficiency. Results All the histogram parameters showed excellent inter-reader consistency, with the ICC values ranged from 0.883 to 0.999. The mean value, 1st, 10th, 50th, 90th and 99th percentiles of TN-IDC group were significantly lower than those of FA group (P < 0.05). The area under ROC curve (AUC) values of mean and n percentiles were from 0.807 to 0.848. However, there were no significant differences in variance, skewness and kurtosis between the two groups (P > 0.05). Conclusion Histogram analysis of gray-scale US images can well distinguish small, oval, or round TN-IDC from FA.

Xue-Feng Li

Papers

Nonlinear parametric vibration of spinning pipes conveying fluid with varying spinning speed and flow velocity

Value of Histogram of Gray-Scale Ultrasound Image in Differential Diagnosis of Small Triple Negative Breast Invasive Ductal Carcinoma and Fibroadenoma