Carbon nanotubes (CNTs) can improve the storage properties of modified asphalt by enhancing the interfacial adhesion of recycled polyethylene (RPE) and base asphalt. In this study, the interaction of CNT/RPE asphalt was investigated using molecular dynamics simulation. The base asphalt was examined using a 12-component molecular model and verified by assessing the following properties: its four-component content, elemental contents, radial distribution function (RDF) and glass transition temperature. Then, the adhesion properties at the interface of the CNT/RPE-modified asphalt molecules were studied by measuring binding energy. The molecular structural stability of CNTs at the interface between RPE and asphalt molecules was analyzed through the relative concentration distribution. The motion of molecules in the modified asphalt was studied in terms of the mean square displacement (MSD) and diffusion coefficient. The results showed that CNTs improved the binding energy between RPE and base asphalt. CNTs not only weakened the repulsion of RPE with asphaltenes and resins, but also promoted the interaction of RPE with light components, which facilitated the compatibility of RPE with the base asphalt. The change in the interaction affected the molecular motion, and the molecular diffusion coefficient in the CNT/RPE-modified asphalt system was significantly smaller than that of RPE-modified asphalt. Moreover, the distribution of the asphaltene component was promoted by CNTs, resulting in the enhancement of the storage stability of RPE-modified asphalt. The property indexes indicated that the storage stability was significantly improved by CNTs, and better viscoelastic properties were also observed. Our research provides a foundation for the application of RPE in pavement engineering.

Food storage helps to ensure the food consumption needs of non-agricultural populations and to respond to major natural disasters or other emergencies, and the application of food storage technology can reduce post-harvest food losses. However, there are still obvious shortcomings in coping with large grain losses. Therefore, quantitative analysis of the research hotspots and evolutionary trends of grain storage technology is important to help the development of grain storage technology. This article uses the Web of Science database from 2007 to 2022 as a data sample with the help of CiteSpace software to analyze the basic situation, research hotspots, and evolutionary trends to draw a series of relevant knowledge maps. Visual analysis revealed that the number of publications had grown rapidly since 2015. First, the Journal of Stored Products Research, Journal of Economic Entomology, and Journal of Agricultural and Food Chemistry, with citation frequencies of 929, 536, and 453, should be focused on in order to keep up with the latest research developments in this field. The United States, China, and Brazil occupy dominant positions in relation to grain storage technology studies in general. Purdue University, Kansas State University, and Agricultural Research Institute ranked the top three in terms of the number and centrality of publications. In terms of research hotspots, the centrality of temperature, insects, carbon dioxide, and quality were 0.16, 0.09, 0.08, and 0.08. It shows that the field of grain storage technology in recent years has focused on grain storage temperature, pest control, and grain storage quality research. From the perspective of the evolution trend, the life cycle of emergent words lasts for several years, after which the strength of emergent words slowly decreases and is replaced by new emergent words. Mortality was the first keyword to appear and remained from 2007 to 2011, indicating that research on fumigants and their toxicity, as well as pest mortality under air fumigation and chemical fumigation conditions, became more popular during this period. In recent years, new terms have emerged that had never been used before, such as “grain quality” (2019–2022) and “stability” (2020–2022). We can find that people pursue food quality more with the improvement of people’s living standards. In this context, future research should seek more efficient, safe, economical, and environmentally friendly methods of grain storage and continuously improve the level of scientific grain storage.

The vertical pressure lead to increased airflow resistance through the grain bulk, which affected the efficiency of ventilation and drying. The effects of vertical pressures at 50, 150, and 250 kPa on the pressure drop characteristics of soybeans were studied using experiment and numerical simulation. The random packing and different compression states for soybean packed beds were generated by the Discrete Element Method (DEM). The Discrete Element Method (DEM) and Computational Fluid Dynamics (CFD) were coupled to investigate the radial velocity and pressure drop of soybean bulk. The simulation results showed that the radial porosity had an oscillating distribution, and the radial average dimensionless velocity was consistent with the distribution trend of porosity. The increase in vertical pressure causes a decrease in porosity and an increase in local velocity. The PathFinder code was used as a supplementary method to calculate the pore path and pore characterization parameters, and the resistance coefficient term in the Forchheimer equation was determined. The compression of soybeans measured by the experiment mainly occurred within two hours after loading. The pressure drop of soybeans increased with the vertical pressure, with the average pressure drop at vertical pressures of 50, 150, and 250 kPa being 36%, 57%, and 92% higher than the uncompressed state (0 kPa). The pressure drop of soybeans calculated by the DEM-CFD method and the Forchheimer equation under different vertical pressures were in close agreement with the experimental results, and an average relative difference was found to be less than 10%. These results provide guidance for estimating the pressure drop of soybeans at different grain depths.

In summer, black asphalt pavement can absorb a considerable amount of solar radiation, which causes its temperature to rise. Heated asphalt pavement can aggravate the urban heat island (UHI) effect and transfer heat downward, which may cause the problem of permafrost thawing beneath pavements. The objective of this study was to develop a novel cool coating layer (CCL) with high near-infrared reflectance and heat insulation to make the surface of asphalt pavement cool. A self-developed test device and method was established to evaluate cooling effects. Based on the experimental results, the optimal coating can cool asphalt pavement by 11.21 °C when the radiation striking the sample surface is 650 W/m². This coating, called the composite cool coating layer (CCCL), is composed of the following materials: polyurethane resin, rutile TiO₂ of 18%, hollow glass microspheres of 12%, and copper chromite black spinel of 0.7%. Silicon carbide particles of 1 kg/m² can help the CCCL achieve satisfactory antiskid performance. In conclusion, CCCL can effectively inhibit the absorption of solar radiation and reduce the flow of thermal energy downward without sacrificing skid resistance.