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A numerical model was established for calculation in this study on the basis of the standard k-epsilon turbulence model and the discrete phase model of the Euler-Lagrange equation. Results of the particle image velocimetry experiment were used to verify the reliability of the numerical model. The effects of the rotation speeds, slurry densities, and impeller structures on the flow field characteristics, including velocity distribution, ballast fluidity, and power loss, were also investigated. The results indicate that the increase of rotation speed has little influence on the flow field near the wall and bottom of the agitator, and the agitator performs well when the speed is set between 30 rpm and 40 rpm. The increase of the slurry density will increase the pressure loss between the inlet and the outlet, and it will also increase the load of the agitator. Hence, the slurry density must be less than 1400 kg/m3. The baffle can improve the velocity distribution of the flow field and the slag discharge capacity of the agitator.

The paper proposed an approach of verifying the Safety Integrity Level (SIL) for the high demand safety system. This approach is based on the Stochastic Petri Nets models and Monte Carlo simulation (SPN-MC) and follows the requirements of IEC61508, which is a commonly accepted standard in the domain of functional safety of programmable electronic and control engineering systems. The paper provides a comparative analysis of the SIL with the application of SPN-MC and the Reliability Block Diagram (RBD) method given by EN61508 to prove the correctness and feasibility of the SPN-MC approach. Additionally, a typical large scaled complex system was adopted to apply the novel approach, which is hard for classical analytical methods.

In order to grasp the pipeline transport characteristics of slurry shield under gravel stratum, with a cross-river tunnel construction of Lanzhou metro as the research background, the numerical simulation method is adopted, and a slurry-stone two-phase flow model is established based on multiphase flow theory by considering the rheological properties of slurry. Besides, corresponding simulation models validated by experiment are established using CFD and DEM softwares, and the impacts of inlet slurry velocity, stone volumetric concentration and pipe inclination angle on pressure drop and transport capacity of the pipeline are investigated. The results show that stones are mainly distributed at the bottom of the pipeline for horizontal straight pipes. The pressure drop and transport capacity increase exponentially with the increase of inlet slurry velocity and stone volumetric concentration. For inclined straight pipes, the pressure drop of the pipeline increases slowly with the pipe inclination angle increasing from 0° to 60°, but increases rapidly when the pipe inclination angle increases from 60° to 90°; the transport capacity reduces slowly at first and then increases rapidly with the increase of pipe inclination angle, and the lowest value appears at 45–60°.

Electroadhesion has a large potential to be extensively used due to its advantages such as lightweight, strong force, and flexibility, but the high excitation voltage (usually more than 1.5 kV) bottle-necks its broad applications. Although increasing the dielectric constant is promising, the dielectric strength and tensile strength become lower simultaneously. Reducing the insulation layer thickness is another possible approach to lower the voltage, but previous fabrication methods and materials do not support this way. This work implants the parylene coating method, which is well-developed in semiconductor industry, into the fabrication of thin insulation layer of the electroadhesive pads. A pad with 7 µm thin insulation layer is demonstrated, and it can generate comparably strong force under 340 V while previous polymer-based insulation requires more than 1.5 kV voltage. For the thin insulation layer, air gap becomes noticeable, and its effects are experimentally studied and analyzed.

The ability to predict fiber orientation accurately is critical for determining the improvement of mechanical properties of injection molded composites. Based on the cumulative distribution function (CDF) monotonically increasing, a smoothing model of piecewise linear approximation function is proposed by assuming that the first derivative is continuous. Taking into account the ability of Weibull distribution reducing to an exponential decay function, a generalized distribution function (GDF) of fiber orientation is proposed by introducing the core thickness ratio (hc) to describe the sandwich layered morphology. Compared with the experimental results in the literatures, the cumulative generalized distribution function fits well (R2 > 0.98), and there is a good correlation (RE

Amongst the present prediction models of mechanical properties, the Weibull distribution has been introduced to describe the fiber length distribution. However, the Weibull distribution cannot capture the long tail decay, leading to underestimation of the fiber length factor (χ2). For the first time, two novel modified distribution functions are proposed based on Erlang-2 distribution and Weibull distribution, respectively. The modified Erlang distribution is derived from introducing a shape parameter to capture the sharp peak better, whereas the modified Weibull distribution is developed by introducing a polynomial function instead of the exponential function to reduce the decay rate for the long fibers. The modified distribution functions are investigated by experimental data reported in literatures and the experimental data of GFRPA66 we obtained. The relationship between the shape parameters (α and β) and k can be described by a linear growth function when α >β, and the slope of α~k is larger than that of β~k. The scale parameters (λ, λα and λβ) can be considered as the linear growth function of ln. The relationship between the improvement in fiber length factor (Δ) and the improvement in number-average fiber length (δ) can be described by a fitting power function with an offset. In comparison to the Weibull distribution, the modified distribution functions improve more than 4% in χ2. The modified Weibull distribution tends to capture the actual fiber length distribution for LFT, whereas the modified Erlang distribution captures that for SFT.

In denoise method for nonlinear time series based on principle manifold learning, reduction targets are chosen at random, using linear method of singular value decomposition solving local tangent space coordinate, these caused efficiency and effect of denoise lower. To solve this problem, a new denoise method based on based on the fractal dimension, higher order statistics and local tangent space arrangement is proposed. The intrinsic dimension is estimated as dimension of reduction targets by fractal geometry method, the data outside intrinsic dimension space will be regarded as noise signal to be eliminated . At the same time, making use of restraining characteristic to colored noise of high-order cumulan, covariance matrix is constructed with the fourth-order cumulant function instead of second-order moment function covariance matrix ,local tangent space alignment algorithm based on fourth-order cumulan is also proposed. Noise reduction experiments on lorenz signal and fan’s vibrating signal show that method proposed in this paper has better denoise effect.

Ideally rolling parameter is symmetrical relative to the rolling center line in the rolling process. When there is asymmetry incentive disturbance, symmetrical state will be destroyed. It brings typical quality problems like strip steering. This chapter studies transverse asymmetry, characteristic of force and deformation of rolling mill and mill bar, establishes asymmetry characteristic quantity of crucial rolling parameter, a relationship equation of asymmetry characteristic parameter of inducement and result state, online detection model which observes asymmetry characteristic parameter of rolling force and corrective model which adjust wedge roll gap, builds graphical solution of characteristic parameter relationship and equation which explains the characteristic parameter.

A high-pressure grinding roll is energy efficient crush equipment. On the basis of mass balance, energy conservation and overall balance, this paper puts forward the intersected idea due to the uneven stress in the roller surface. The grinding and comminution model of roller press is deeply investigated. It puts forward crush model using mathematic theory. The simulated specific energy consumptions and particle size distributions, compared with the experiment data, were considered good enough. The model was able to predict adequately throughput capacity, specific energy consumption and particle size distributions of the edge, center and total products.

Combining the advantages of model-based testing (MBT) method in the testing-automation field, as well as the advantages of TTCN-3 testing language in the field of the message-based black box testing, this paper presents a automatic testing approach of distributed real-time System based on the MBT and TTCN-3. Under the premise of considering the complexity and the real-time features of the distributed real-time system, this method first decomposed the distributed real-time system into multiple entities; for each entity, using an extended time Input/Output Automata—Labeled-ports TIOA(LpTIOA) to describe the entity according to its functional requirement specification; then derive the test case set based on an improved search algorithm; and then transfer these test cases into TTCN-3 language described test cases according to the seven regulation presented in this paper; finally achieved the TTCN-3 test platform and complete some functional tests on the CTCS-3 Level Onboard subsystem.

With the fast development of the communication technology, the reliability and the availability of the wireless-communication have been greatly improved, and the Communication Based Train Control System (CBTC) has been formed. The Zone Controller is a subsystem of the CBTC system, which plays the role of computing and presenting Movement Authority (MA) to the train and managing the train. So the safety of the ZC subsystem will directly influence the safety of the train. This paper has taken the ZC subsystem as an example, particularly the functions of MA computation, to describe a Functional Safety Analysis Approach and its concrete implementation in the CBTC system.