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The rheological behavior of concrete pumping in the bend section is complex. The existing conversion calculation for pumping pressure loss based on the straight pipe section often fails to meet engineering precision requirements. This paper develops a pressure loss correction model for a concrete pumping bend section based on a new one-dimensional flow model for the straight pipe section simulation of particle flow; the study analyzes the impact of parameters such as elbow shape and pumping flow rate on pressure loss. An equivalent conversion relationship between the bend section and the straight section is established. The comparison with the measured pressure values from the project shows that the relative error between the pressure loss values calculated by the correction model and the actual measurements is 15.8%. [ABSTRACT FROM AUTHOR]

The stability and Hopf bifurcation of a class of flywheel governor systems subject to stochastic excitation under time-delay feedback are studied. The model is simplified using center manifold reduction to obtain a paradigm for a two-dimensional central subsystem. The system converges asymptotically to an Itô stochastic differential equation based on polar transformations and stochastic averaging method. The stochastic stability of the system is analyzed by applying the maximum Lyapunov exponent and the singular boundary theory, and its probability density function is calculated. In addition, it is found through Monte Carlo numerical simulations that the effects of noise intensity and time-delay on the stochastic P-bifurcation of the system are opposite, and proper noise intensity makes the flywheel governor system converge to the equilibrium position, while a large time-delay leads to stochastic bifurcation and makes the flywheel governor system unstable. Finally, the two-parameter bifurcation diagram is used to further analyze the impact of time-delay and noise intensity on the bifurcation of the system under variable load torque. It is found that the influence of noise intensity and time-delay on the periodic oscillation state is the same, and the stability of the flywheel governor system will decrease with both of their increases. This also further demonstrates the duality of the impact of noise intensity on the same system under different conditions. The above research provides better theoretical references for the design and safe operation of speed control systems. [ABSTRACT FROM AUTHOR]

In this paper, a wind turbine generator drive system with stochastic excitation under both displacement and velocity delayed feedback is considered. Firstly, the center manifold method is used to approximate the delay term of the system, so that the Itô-stochastic differential equation can be obtained by random average method. Through the maximal Lyapunov exponential method, the local stochastic stability and random D-bifurcation conditions of the system are obtained. Secondly, it is verified that the increase of noise intensity and delay value induces the occurrence of random P-bifurcation of the system through Monte Carlo numerical simulations. In addition, the theoretical chaos threshold of the system is derived by the random Melnikov method. The results show that the chaos threshold decreases as the noise intensity increases, and the increase in time delay leads to a delay in the chaotic behavior of the system. Finally, the correctness and effectiveness of the chaos-theoretic analysis are verified based on the one-parameter bifurcation diagrams and the two-parameter bifurcation diagrams. [ABSTRACT FROM AUTHOR]

The success of the two mRNA vaccines developed by Moderna and BioNTech during the COVID-19 pandemic increased research interest into the application of mRNA technologies. Compared with the canonical linear mRNA used in these vaccines, circular mRNA has been found to mediate more potent and durable protein expression and demands a simpler manufacturing procedure. However, the application of circular mRNA is still at the initiation stage, and proof of concept for its use as a future medicine or vaccine is required. In the current study, we established a novel type of circular mRNA, termed cmRNA, based on the echovirus 29-derived internal ribosome entry site element and newly designed homology arms and RNA spacers. Our results demonstrated that this type of circular mRNA could mediate strong and durable expression of various types of proteins, compared with typical linear mRNA. Moreover, for the first time, our study demonstrated that direct intratumoral administration of cmRNA encoding a mixture of cytokines achieved successful modulation of intratumoral and systematic anti-tumor immune responses and enhanced anti-programmed cell death protein 1 (PD-1) antibody-induced tumor repression in a syngeneic mouse model. This novel circular mRNA platform is thereby suitable for direct intratumoral administration for cancer therapy., Competing Interests: One patent has been filed to protect cmRNA as well as its application (inventors Z.S., C.Z., and J.Z.), one patent has been filed to protect the use of circular mRNA administrated intratumorally as anti-tumor therapy (inventors C.Z., J.Y., and Y.T.), and one patent has been filed to protect the use of Ringer’s solution for circular mRNA intratumoral administration (inventors J.Y., Y.T., and J.Z.)., (© 2022 The Authors.)