Abstract: Passive daytime radiative cooling (PDRC) technique can cool objects without energy consumption by reflecting sunlight and radiating heat into the cold outer space through atmospheric transparent windows (ATW). Here, 3D porous polydimethylsiloxane (P-PDMS) films with excellent radiative cooling properties were fabricated using citric acid monohydrate (CAM) templates. Integrating with high sunlight reflectance (78.6%) and great thermal emissivity (99.4%) in ATW, the test was performed in an outdoor environment with an average solar radiation of 715.09 W/m2. The maximum temperature of P-PDMS film is reduced to 15.4℃, and in the actual roof application test, P-PDMS film also show excellent passive radiant cooling performance of 8.3℃ cooling in the house. The 3D-porous structure plays an important role in improving solar reflectivity and IR emissivity. Combined with efficient DRC capabilities and mass production compatibility, this work brings a new paradigm for the preparation of cooling devices with potential commercial applications in sustainable energy-free cooling. Read More

Abstract: With the increasing stringency of emission standards, the challenge for conventional passenger vehicles to meet evaporative emission requirements has intensified. Evaporative emissions from vehicles are primarily derived from the fuel system and the non-fuel system, with the latter accounting for 30% to 50% of total vehicle emissions. Thus, the study of non-fuel system evaporative pollutants in passenger vehicles has become especially important. This research conducted tests on automobile seat assemblies and their components to identify the main pollutants. Through the contribution of concentration ratios, a predictive formula was established to validate tests related to seat assemblies and components, aiding enterprises in effectively controlling non-fuel evaporative pollutants from automobile seats. Read More

Abstract: The mining of inclined coal seams is often accompanied by problems such as difficult to control deformation of the tunnel roof and failure of anchor bolts. Taking the transportation channel of Jinping Coal Industry 1071-1 in Shanxi Xiangkuang Mine as the background, FLAC3D numerical simulation software was used, and the method of response surface experimental design and data analysis was used to systematically study the effects of the anchor installation angle and the roof inclination angle of the tunnel section on different inclination angles. Influence of the surrounding rock stability of coal seam roadways. On this basis, a multi-index tunnel support design evaluation method based on the response surface method was proposed, and the actual support plan was optimized and industrial tests were carried out based on the actual on-site support plan. The research results show that: in terms of inclined coal seam support, the degree of influence on the tunnel stability is in the following order: anchor installation angle > tunnel section roof inclination angle > coal seam inclination angle; the optimized support design obtained through the proposed technology The method has good application effect and can improve the stability of the roadway during the mining of the working face. It also proves the effectiveness of this technology and provides new ideas for the design of anchor support of inclined coal seam roadways and the optimization of roadway sections. Read More

Abstract: Aramid nano-aerogel represents an ideal structure for the fabrication of next-generation high-performance thermal insulation fibers and textiles. Single aramid nano-aerogel fiber can be achieved via wet spinning. The thermal conductivity of these fibers, a crucial determinant of textile insulation performance, remains under-explored in terms of numerical modeling. This research aims to establish a numerical inversion model to determine the thermal conductivity of single aramid nano-aerogel fiber. By simulating the three-dimensional geometry of plain fabric, the volume fraction of gas and solid within the fabrics are computed. Drawing from the law of energy conservation and Fourier's law of heat conduction, a relationship model is proposed between the thermal conductivity of single aramid nano-aerogel fiber and the overall thermal conductivity of the fabric. The finite difference method is employed to ascertain the thermal conductivity of single aramid nano-aerogel fiber. Furthermore, the influence of the geometric structure and the fiber diameter on the thermal insulation performance of the single-layer fabric is analyzed, which provides a feasible approach for the subsequent design of fabric structures with excellent thermal insulation properties. Read More

Abstract: In recent years, with the development of industry and scientific technology, the demand for materials has been increasing. Fatigue crack propagation is an important issue in the field of materials, and developing relevant theories and methods, understanding the mechanisms of fatigue cracks, and making scientific predictions on fatigue crack propagation are hot topics both domestically and internationally. Fracture mechanics, as a discipline studying the strength and propagation of cracks in materials, has developed a relatively complete theoretical system and engineering application methods over more than 100 years of continuous development. This article focuses on the effects of factors such as temperature, stress ratio, and load frequency on the fatigue crack propagation characteristics of metallic materials, and summarizes the common theories and methods of fatigue crack propagation. Read More

Abstract: With the progress of modern society, people's awareness of environmental protection is gradually enhanced, and the problem of environmental protection is also increasingly paid attention to. At present, various green environmental protection coatings have become popular in many countries and regions. Green environmental protection coating as a new, efficient, safe and pollution-free environment-friendly coating, on the premise of sustainable development, through continuous innovation and research and development, can not only protect the natural environment, but also beneficial to human health. The purpose of this paper is to give a brief overview of green coatings, introduce the application status and production development of green coatings, and summarize the possible development trends and prospects of green coatings in the future. Read More

Abstract: Q235 steel is widely used in industry and daily life, and it is prone to corrosion during use, especially in hydrochloric acid solution where corrosion is particularly severe. Schiff base organic compounds can significantly inhibit the corrosion of Q235 steel in hydrochloric acid solution, making them a green and environmentally friendly organic compound. This article uses aniline, octadecylamine, and glutaraldehyde as raw materials to prepare two Schiff base corrosion inhibitors, namely bisaniline Schiff base and bisoctadecylamine Schiff base (named BXFJ and SXFJ respectively). The corrosion inhibition performance and mechanism of these two Schiff base inhibitors in Q235 steel in hydrochloric acid solution were studied using weight loss method, electrochemical testing, quantum chemical theory calculation, and molecular dynamics simulation. The results of weight loss method and electrochemical testing show that in a 1mol/L HCl solution, the corrosion inhibition performance of BXFJ at a concentration of 25mg/L is higher than that of SXFJ, indicating that BXFJ can exert excellent corrosion inhibition performance in HCl environment. Density functional theory (DFT) indicates that the active sites of the two Schiff bases are C=N double bonds, and molecular dynamics (MD) further confirms that both Schiff base corrosion inhibitors can adsorb on the surface of Q235 steel. Read More

Abstract: SLM5600 vertical roller mill is widely used in 6000t/d cement clinker production line, the main parts of SLM series mill is a whole disc and three grinding roller, the roller in addition to the regular change with the liner accident, also need to regularly check and change with the bearing and oil seal and the wear bushing, by SLM5600 roller mill Department of heavy cement plant machinery maintenance conditions are limited, many manufacturers can only be shipped back to my company roller for repair and replacement parts, resulting in long period of maintenance, repair costs, provide a set of field assembly roller assembly process in this paper, according to the process maintenance workers on-site replacement parts and grinding roller assembly. Read More

Abstract: The steel tube concrete structure constrains the core concrete through the inner wall of the steel tube, forming a hoop effect, significantly improving the compressive performance of the core concrete and effectively exerting the tensile performance of the steel tube. Although this structure has been optimized in terms of mechanical properties, its ultra-high bonding performance makes it extremely difficult to disassemble and recycle. To explore ways to solve this challenge, this article selects C40 concrete as the matrix concrete, and designs and produces circular steel tube concrete specimens and square steel tube concrete specimens with a height of 250mm and a steel tube wall thickness of 4mm. The specific research content covers the hoop effect of steel pipes on core concrete, the degradation law of thermal expansion and contraction interface bonding performance of steel pipe concrete components, the coupling effect of cutting joints and thermal expansion and contraction on interface bonding performance of steel pipe concrete components, and the mechanism of interface debonding of steel pipe concrete components. Through systematic experiments and analysis, the influence of different variation parameters on the debonding performance of steel tube concrete was deeply studied, and its debonding mechanism was revealed. This series of studies provides an important scientific basis for the theoretical understanding and application of steel-concrete structures, helping to overcome the problem of dismantling and recycling, and promoting the transformation and development of related equipment. Read More

Abstract: A series of Ni-Cu co-doped spinel LiMn1.92-xCu0.08NixO4 cathode materials were successfully synthesized by a solution combustion method. X-ray diffraction (XRD) spectra showed that all the as-prepared LiMn1.92-xCu0.08NixO4 samples belong to spinel LiMn2O4 structure without any impurity phase. Scanning electron microscopy (SEM) showed that the particle size of the samples decreased with the increase of Ni-doping amount, and the crystallinity increased gradually. The galvanostatic charge/discharge tests results showed that the LiMn1.86Cu0.08Ni0.06O4 sample shows excellent rate performance and cyclic stability. At room temperature and 1 C, the initial discharge specific capacity of LiMn1.86Cu0.08Ni0.06O4 was 103.4 mAh g-1, and the capacity retention rate of 67.80% was obtained after 1000 cycles, which was higher than 49.60% of LiMn2O4. Even at high current densities of 5 C and 10 C, the good capacity retention rates of 73.55% and 67.29% for LiMn1.86Cu0.08Ni0.06O4 sample were obtained after 1000 cycles, respectively. Read More

Abstract: In order to investigate the compression performance and damage mechanism of fallen wood in the down-grain direction, northeast larix was taken as the research object. Through the monotonic compression test of 12 specimens, the deformation characteristics, damage mode, and stress-strain curve properties of larix wood under compression in the direction of the smooth grain were analyzed; scanning electron microscope technology was used to analyze the damage and fracture characteristics of wood fibers from the microscopic point of view to further reveal the damage mechanism of wood monotonic compression. The results showed that larix wood compressed in the paragons produced three damage modes of end collapse, shear damage and paragons splitting after the peak load, and the shear damage usually occurred at the junction of the early and late wood tubular cells due to the difference between the early and late wood tubular cells. On this basis, an isomorphic model was established to describe the compression of larix wood in the smooth grain. Read More

Abstract: To improve the waste rubber powder modified asphalt viscosity is high, poor storage stability, and other shortcomings, 40 mesh, 60 mesh, and 80 mesh are three kinds of mesh rubber powder using rapeseed heavy oil pre-swelling activation way to prepare modified asphalt, improve the waste rubber powder modified asphalt storage stability and reduce the viscosity. The optimum blending amount of rapeseed heavy oil-activated waste rubber powder was determined by setting three oil-rubber ratios, and the unactivated waste gum powder modified asphalt was set as a control group, and the physical, rheological, and microscopic properties of the asphalt were evaluated accordingly. The optimum preparation parameters under the premise of setting the total dosage of modifier as 20% were: the mass ratio of rubber powder to rapeseed oil was 2:1, and the mesh size of rubber powder was 80 mesh. Rapeseed heavy oil-activated waste rubber powder modified asphalt storage stability and low-temperature performance improved, viscosity decreased, but high-temperature performance decreased at the same time. Compared with the unactivated waste rubber powder modified asphalt, the softening point decreased by an average of 16%, the needle penetration increased by an average of 19%, the ductility increased by an average of 44%, the viscosity decreased by an average of 22%, and the softening point difference decreased by an average of 44%. In the high-temperature rheological performance test set temperature interval, the rutting coefficient G*/sinδ decline, creep stiffness Ѕ, and creep rate m have increased. Therefore, rapeseed heavy oil activation can effectively improve the overall stability of waste rubber powder-modified asphalt and can reduce the overall viscosity, which is conducive to the uniform dispersion of rubber powder in asphalt. Read More

Abstract: In order to solve the problem that it is difficult to predict the microcavity photonic energy bands of point defects in two-dimensional silicon-based dielectric column photonic crystals, this paper proposes a method to predict the microcavity photonic energy bands of point defects in two-dimensional silicon-based photonic crystals by using an artificial neural network model. In this paper, the energy band structure of triangular lattice point defects at different radii is calculated using MPB, and a neural network model is established based on this data and the accuracy of the established model is verified. Read More

Abstract: This article reviews the properties and application prospects of graphene based anti-corrosion composite materials in the field of anti-corrosion. This article mainly introduces the preparation methods and property testing results of composite materials such as graphene/polyaniline, graphene oxide/aluminum tripolyphosphate, and silica graphene oxide. Through hardness, impact resistance, electrochemistry, and salt spray resistance tests, the superiority of graphene based composite materials over individual anti-corrosion coatings has been revealed. The future outlook is on how to change the current situation, improve anti-corrosion effects, and point out the development direction of composite materials. This review aims to provide reference for the research of graphene anti-corrosion composite materials and promote their application in the field of anti-corrosion coatings. Read More

Abstract: This paper discusses the different types of B… co-doped graphene, such as neighborhood, intercalation, para-doping on the carbon six-membered ring of monolayer graphene, and monolayer and stacked doping of h-BN with graphene. The structure and characterization of each type are examined. Additionally, the impacts of B… co-doping on the optical properties, O2 adsorption, and chemical properties of graphene are explored. Finally, the future challenges in boron and nitrogen co-doped graphene research are outlined. Read More

Abstract: In this paper, the effects of deep processing of metallic mineral materials on electromagnetic wave absorption properties were studied. Firstly, the background and significance of the research are introduced, and the importance of metallic mineral materials in the field of electromagnetic wave absorption is expounded. Then the basic principle of electromagnetic wave absorption and the characteristics and influencing factors of metal mineral materials are discussed. In the section of deep processing technology, different processing methods and their applications are listed. Through experimental design and method, the electromagnetic wave absorption properties of metal mineral materials after deep processing are tested and analyzed. The experimental results are obtained and discussed. Finally, the application prospect of metallic mineral materials in electromagnetic wave absorption field is prospected, and the technical improvement and future development direction are put forward. This study provides an important reference for deepening the understanding of electromagnetic wave absorption properties of metallic mineral materials, and provides a reference for further research in related fields. Read More

Abstract: With the depletion of fossil fuels causing a series of energy and environmental problems, accelerating the development of green and clean energy is urgent. Supercapacitors are favored by researchers due to their excellent performance such as high specific energy and good stability. Biochar is obtained from biomass materials after pre-carbonization and activation treatment, with developed pore size, high active specific surface area, and abundant resources. It has good application prospects as a supercapacitor material. This article provides a brief introduction to biomass charcoal materials and introduces the preparation methods of biomass charcoal and its research progress in the field of supercapacitors. Finally, it looks forward to the development trend of biomass charcoal materials, providing a reference for further improving the research application of biomass charcoal materials in the field of supercapacitors in the future. Read More

Abstract: In order to reduce the negative impact of phosphogypsum accumulation on the environment, this paper uses phosphogypsum, magnesium slag, potassium dihydrogen phosphate, fly ash and calcium carbide slag to prepare gypsum based plaster mortar as a cementing material, and explores the optimal ratio of the composite cementing material through orthogonal experimental design. The mechanical properties of the test block were analyzed by the flexural and compressive strength of the test block, and the slurry properties were evaluated by the initial and final setting time, stability measurement, fluidity test and water resistance test. The experimental results show that when phosphogypsum: potassium magnesium phosphate: fly ash: When titanium gypsum =50:25:20:20, the strength of the composite system can reach 2.98Mpa in 60 days, and the initial setting time is 118min and the final setting time is 223min, which meets the requirements of GB/T25181-2019 building gypsum plaster mortar that the initial and final setting time is greater than 60min and less than 480min. Its fluidity is 237mm, which meets the requirement that the fluidity of GB/T25181-2019 building gypsum plaster mortar is greater than 100mm. Read More