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Effects of aggregate size and shape on monotonic shear behaviour of unreinforced and geogrid-reinforced aggregate interfaces were systematically investigated through direct shear tests. Five different grades of angular aggregates and five kinds of rounded aggregates with identical particle size distribution were selected as test materials. Experiment results revealed the coupling effects of particle shape and aperture ratio (AS/D50), defined as the ratio of geogrid aperture size (AS) to the average particle size of aggregate (D50), on the shear behaviour of the unreinforced and reinforced interfaces. The peak shear stress, shear displacements corresponding to peak shear stress and residual shear stress, as well as maximum dilation of aggregate–geogrid interfaces at each AS/D50 were greater than those of glass beads–geogrid interfaces. The largest interface shear strength coefficient of aggregate–geogrid interfaces was achieved at AS/D50 = 2.55, and the optimum reinforcement of glass beads–geogrid interfaces appeared at AS/D50 = 5.05. The shear strength decreased more after the peak when the value of AS/D50 was relatively small, and the post-peak strength reduction of aggregate–geogrid interfaces was more pronounced. A generalised stress-dilatancy relationship was proposed, which introduced a variable dilatancy index (ζ) that reflected the effects of aperture ratio and particle shape. [ABSTRACT FROM AUTHOR]

With the growing trend of higher running speed and lighter body weight in the high-speed train, the influences of fluctuating crosswind on running stability and safety are becoming more and more not negligible, especially under the combined action of unsteady aerodynamic loads and random orbital excitation. In order to investigate this problem, a vehicle dynamic model of with 42 degree of freedom is built, in which the major body, two bogies and eight wheels are involved. The unsteady aerodynamic loads under stochastically fluctuating crosswind are obtained based on Cooper theory and the harmonic superposition method, and the random excitation of the track is also taken into consideration. For the vertical vibration originated from the fluctuating crosswind and the random track spectrum, the skyhook damping and the magneto-rheological fuzzy semi-active control strategies are individually applied to suppress the vibrating amplitude and improve the running stability. It is indicated that the vertical vibration under the coupling influence of the unsteady aerodynamic loads and the random orbital excitation are significantly increased, and the vibrating amplitude can be effectively suppressed by both the two different control approaches. It is also shown that the index of running stability in the case of the fuzzy control is evidently better than the skyhook damping. [ABSTRACT FROM AUTHOR]

The effect of Cux substituted for Gax on the thermodynamic characteristic, evolution of phases and fracture behavior in Ni50Mn30Ga20 − xCux alloys have been investigated. The results show that the martensitic transformation, reverse transformation temperatures and average interface temperature of Ni50Mn30Ga20 − xCux sample increase remarkably with increased content of Cu. The hysteresis temperature of the austenite to martensite transition firstly showed a steep rising trend, then almost reduced to a lower rate with the increased content of Cu up to 4 at.% (the maximum level of copper addition studied). The (202) diffraction peak position was observed to shifted towards high angles, when the Cu content was lower than 1 at.%. Further, the, M202 diffraction peak was found to split into two diffraction peaks when the Cu content was more than 1 at.%. In addition, the compressive strength and fracture strain of alloys is clearly enhanced with increased content of Cu. Furthermore, the fracture type of Ni50Mn30Ga20 − xCux alloys was found to changes from intergranular fracture for the Ni–Mn–Ga alloys, to transgranular cleavage fracture with increase in Cu content. [ABSTRACT FROM AUTHOR]

In the case of two-way traffic, there are two opposite-direction flows on every road and serious unsymmetrical flows exist in rush-hour periods. One of the primary methods used for handling this kind of traffic flow is the use of reversible lanes. Which and how many lanes should be adjusted are optimization problems. They can be treated as a network design problem, i.e. the optimal decision on the resource distribution of a street and highway system in response to a growing travel demand. This article studies a new form of transportation network design problem by performing the strategy of reversible lanes. In order to describe this problem, a bi-level programming model is given in which the upper level model is to make the total system cost and flow entropy minimum, while the lower level is a stochastic user equilibrium assignment with an advanced traveller information system. Finally, the numerical example shows that, by adopting the reversible lane and advanced traveller information system, the total system cost will be greatly reduced. [ABSTRACT FROM AUTHOR]

In order to solve the problems of the 2.45 GHz magnetron used in asphalt pavement maintenance as the longer heating time and high energy consumption when heating unit area, the paper brings forward the 5.8 GHz magnetron using in asphalt pavement maintenance. CST and ANSYS simulation software were first used to study the temperature rise and depth of heating asphalt pavement using 2.45 GHz and 5.8 GHz magnetron. Then the experimental verification was carried through. The 5.8 GHz magnetron can be used effectively in asphalt pavement maintenance. The research results show that: the temperature rising rate of the 5.8 GHz magnetron heating asphalt pavement is 2–3 times of 2.45 GHz magnetron in the distance within 0–75 mm of the asphalt concrete pavement. Heating 8–10 minutes, temperature rise within 0–75 mm of asphalt pavement can meet the asphalt road surface maintenance. The heating asphalt pavement depth of 5.8 GHz magnetron which is about 7 cm–8 cm is half of the 2.45 GHz magnetron. Heating the same area of asphalt pavement to the same temperature, the input power of 5.8 GHz magnetron maintenance equipment is 1/3 of the 2.45 GHz magnetron maintenance equipment. [ABSTRACT FROM AUTHOR]

The paper puts forward microwave deicing after analyzing the shortage of deicing using chemistry, thermal and mechanism. It points out that study of microwave deicing is restricted by deicing efficiency. In order to improve the microwave deicing efficiency and achieve fast deicing in winter road maintenance, the influence factors of microwave deicing efficiency are studied. Then frequency of microwave is simulated by CST software. The findings indicated that deicing efficiency is concerned with the microwave frequency, electric field intensity of microwave, road material, environmental temperature, thickness of ice, impurity content of ice, heating mode of microwave, distance between road and waveguide mouth and so on. At the same condition, the deicing efficiency of 5.8 GHz magnetron is four times more than 2.45 GHz magnetron. [ABSTRACT FROM AUTHOR]