Stability analysis of unsaturated clay slope based on the coupled effect of temperature and saturation

In view of the clay slope instability caused by environmental temperature and rainfall infiltration in summer and autumn, the mechanism of the effect of temperature and saturation on unsaturated clay slope stability was discussed. To achieve this objective, this study uses the theoretical and numerical methods. Based on the theory of unsaturated clay and the law of heat conduction, the relationship between cohesion and matrix suction of unsaturated clay was derived considering the influences of temperature and saturation. Considering the effect of temperature and saturation, the coupling equation of shear strength of unsaturated clay was constructed under conditions of rainfall infiltration. The coupling equation of temperature and saturation was used in the strength reduction method, and the slope stability was analysed by FLAC software. The results show that the cohesion of unsaturated clay slope increases with the increase of depth, and the safety factor considering the coupled effect of temperature and saturation is smaller than that without considering the temperature effect; the clay slope is unstable considering the coupled effect of temperature and saturation, but stable without considering the coupled effect when the saturation of soil reaching 80%.Thematic collection: This article is part of the Role of water in destabilizing slopes collection available at: https://www.lyellcollection.org/cc/Role-of-water-in-destabilizing-slopes

Influence of optical loss on nonlinear effect in stimulated Raman scattering system

In this paper, based on the ideal stimulated Raman coupling equation, the dynamic output state is investigated. Considering the gain and loss of stimulated Raman scattering in the actual situation, the ideal stimulated Raman coupling equation is modified. Furthermore, the influence of optical loss on the nonlinear effect in the stimulated Raman scattering system has been analyzed. The results show that, considering the gain and loss of the system, the dynamic output of the stimulated Raman coupling equation presents stable periodic oscillation and random oscillation.

MODELING AND OPTIMIZATION OF THE PROCESS OF GEAR MILLING OF CYLINDRICAL GEARS WITH WORM MILLING CUTTERS

The paper considers influence issues of modes of milling cylindrical gears by hobbing cutters on the parameters of surface quality of the treated teeth, selection of milling mode, relevance of the performed research, possibility of using its results for the design of technological processes of manufacturing cylindrical gears, quality control of teeth surfaces both when cutting teeth and in finished gears. The article gives a method, conditions and main results of experimental study of the influence of gear milling modes by a worm milling cutter (feed S, mm/min; cutting speed V, m/min) of cylindrical gears on the roughness parameter Ra, μm; microhardness Hμ, MPa; macroscopic and microscopic stresses of σ1 and σ2, MPa; of the tooth surfaces. It is shown in particular that the dependence of Ra on V and S with sufficient accuracy (the average relative error of the coupling equation εср is 5.2–26.5 %) can be described by a firstdegree polynomial, and the dependences of Hμ, σ1 and σ2 on V and S with sufficient accuracy (εср = 4.7–12.8 %) can be described by a second-degree polynomial. It was found that the feed S has a 2.5–14 times greater effect on the change in Ra, Hμ, σ1 and σ2 than the cutting speed V during gear milling of cylindrical gears. A method for optimizing the cutting modes S and V is proposed and described, taking into account their influence on the main parameters of the process of gear milling of cylindrical gears with worm milling cutters.

Dynamic damage analysis of airfoil flutter for a generic hypersonic flight vehicle

The main aim of this paper is to establish the relationship between the airfoil flutter with the flight dynamics of a generic hypersonic flight vehicle (HFV) and analyze the airfoil damage variation during the airfoil flutter. Based on the motion equations of the two degrees of freedom airfoil model and the longitudinal dynamics of the HFV, an airfoil dynamic model is established. By using a coupling equation, the relationship between airfoil flutter and the flight dynamics is estimated. According to the stress–strain ([Formula: see text]) model and the strain–fatigue damage ([Formula: see text]) model, the influence of the stress on the airfoil flutter damage is analyzed. The simulation results show that the flutter of the airfoil is closely related to the flight dynamics for the HFV and the airfoil flutter damage is closely related to the flutter amplitude of the airfoil.

Impact of Environmental Investments and Air Protection Costs on the Sustainable Development of Coal Mining Regions

The transition to sustainable development of mining regions depends on the size and effectiveness of environmental investments. This study examines the impact of investments and current costs of air protection on the amount of air emissions from stationary sources. We used data on investments in atmospheric air protection, current costs of air protection, and amounts of air emission in 12 mining regions of Russia. The impact of investment and emission costs was simulated using standard pairwise regression equations and the Almon distributed lag model. The statistical insignificance of the models has been established, both in terms of the form of coupling equation and the significance of most coefficients with explanatory variables. The distributed lag model using data on investments in air protection over five years is also statistically insignificant. The paper also discusses the impact of investments and current costs on the specific emission amount per 1 ruble of the gross regional product. The model of pairwise linear regression and other possible forms of the coupling equation in this case are statistically insignificant. The study found that investments and current costs do not affect emissions from stationary sources. This suggests a lack of investments in the air protection and a low efficiency of their use.

Decomposition of healing tensor: In continuum damage and healing mechanics

The decomposition of the healing variable (in the case of scalars) and the healing tensor (in the case of tensors) is carried out systematically and consistently. In this respect, the classical linear healing model is adopted in this work. The decomposition of healings includes the healing variable/tensor of cracks and the healing variable/tensor for voids. A third defect type is considered wherever mathematically possible. Thus a complete treatment of the decomposition of the healing tensor is presented covering both the one-dimensional and three-dimensional aspects. As an illustrative example, the case of plane stress, plane damage, and plane healing is solved. In this case, it is concluded that two distinct decomposition equations are obtained as well as one single coupling formula. The coupling equation is an expression that relates the various healing tensor components and damage tensor components for cracks and voids Furthermore; it is shown that there is no coupling in the one-dimensional case.

Constructing a Variable Coefficient Integrable Coupling Equation Hierarchy and its Hamiltonian Structure

How to construct a variable coefficient integrable coupling equation hierarchy is an important problem. In this paper, we present new Lax pairs with some arbitrary functions and generate a variable coefficient integrable coupling of Ablowitz-Kaup-Newell-Segur hierarchy from a zero-curvature equation. Then the Hamiltonian structure of the variable coefficient coupling equation hierarchy is derived from the variational trace identity. It is also indicated that this method is an efficient and straightforward way to construct the variable coefficient integrable coupling equation hierarchy.

Research on Underwater Vehicle and Tail Gas Mass Coupling Process

Rayleigh equation was applied to establish the model of the underwater vehicle tail gas mass developing process. The interrelationship of tail gas mass radius and pressure of was analyzed. The interaction equation between tail gas mass change and vehicle motion parameters was studied by coupling equation of gas mass and vehicle motion. The result shows that the simulation result agree with experimental results well, and show that the change of environment pressure with different work situations. The bigger initial pressure is, the longer oscillation period of vehicle tail pressure is. The bigger initial pressure is, the bigger initial acceleration is, but the acceleration is distinctly attenuate with time.