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Hot-in-place recycling of asphalt pavement is one of the important regeneration technologies of pavement engineering, which apply to the pavements with fewer diseases, excellent driving quality, slight rutting, and good pavement structural strength. However, the surface layer of some road sections was aging, the penetration index of aged asphalt at 25°C is lower than 20(0.1mm), which does not meet the recommended requirements of the criterion in China. In 2019, 3 sections of test projects were laid on the expressway, each section was 1 km, for confirming the feasibility of using hot-in-place recycling with asphalt penetration less than 20 (0.1mm) through physical engineering. Experimental results confirmed that Marshall stability, residual stability, dynamic stability and water seepage of the hot-in-place recycled mixture optimized by the recycled pavement material with a penetration of aged asphalt of 15 can meet the specification requirements, Pavement Condition Index (PCI), International Roughness Index (IRI), and Rut Depth (RD) of the test pavements are in good conditions.

Diamond possesses extremely excellent properties, which make it a potentially transformative material in an extensive range of applications. Herein, diamonds were synthesized in a FeNiCo–C system with B2S3 as an additive by a temperature-gradient growth method at high temperature and high pressure (HPHT) conditions. The effects of the B2S3 additive in the FeNiCo–C system on diamond crystallization were characterized using Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements. FTIR result shows the presence of positive-charged N+ in the diamond crystal synthesized with the B2S3 additive, and its concentration was estimated to be around 30 ppm. Moreover, the XPS measurements confirm that N+ can combine with boron to form a B–N bond. Furthermore, the Hall effect result indicates that the resistivity of the diamond crystal synthesized with B2S3 was reduced to 3.89 × 10 Ω cm, whereas, the resistivity of the diamond synthesized with the same weight of B2S3 additive along with Ti/Cu as the nitrogen removal agent dropped sharply to 2.51 × 10−1 Ω cm. [ABSTRACT FROM AUTHOR]

The finite volume discrete solution of the Navier-Stokes equation and the RNG model of the turbulence model are used to numerically simulate the flow and heat transfer characteristics of supercritical kerosene in a circular tube. The results show that as the inlet mass flow increases, the wall surface temperature and the central flow oil temperature gradually decrease, and the pressure loss becomes larger. As the inlet temperature increases, the wall surface temperature and the central flow oil temperature both increase. When the heat flux density is constant, as the pressure increases, the deterioration of heat transfer will be weakened, and increasing the pressure can improve the effect of convection heat transfer.

This paper presents a CFD simulation analysis method for the regenerative cooling channel of a supercombustion ramjet engine, and performs three-dimensional modeling and analysis. The influences of inlet mass flow, inlet pressure, and inlet temperature on the flow and heat transfer characteristics of kerosene in the cooling channel were analyzed, and the conclusions are as follows: The larger the inlet mass flow, the lower the maximum wall temperature and oil temperature. The change trend of wall temperature is basically the same under different inlet pressure conditions, all of which increase violently first, then stabilize and then suddenly increase suddenly, then decrease almost to the outlet, and the temperature is almost the same under different conditions.As the inlet temperature decreases, the temperature difference between the wall surface and kerosene becomes larger, and the convective heat transfer coefficient gradually increases.