The growth year of ginseng is very important as it affects its economic value and even defines if ginseng can be used as medicine or food. In the case of large-scale developments in the ginseng industry, a set of non-destructive, fast, and nonprofessional operations related to the growth year identification method is needed. The characteristics of ginseng reflectance spectral data were analyzed, and the growth year recognition model was constructed by a decision-tree-based random forest machine learning method. After independent verification, the accuracy of distinguishing ginseng food and medicine can reach 92.9%, with 6-year growth as the boundary, and 100%, with 5-year growth as the boundary. The research results show that the spectral change of ginseng is the most obvious in the fifth year, which provides a reference for the key research years based on chemical analyses and other methods. For the application of growth year recognition, the NIR band (1000–2500 nm) had little contribution to the recognition of ginseng growth years, and the band with the largest contribution was 400–650 nm. The recognition model based on machine learning provides a non-destructive, fast, and simple scheme with high accuracy for ginseng year recognition, and the spectral importance analysis conclusion of ginseng growth years provides a design reference for the development of special lightweight spectral equipment for year recognition.
Earthen sites are easily eroded by the natural environment, resulting in a large number of micro cracks on the surface. In order to explore the internal relationship between environmental factors and the cracking law of soil sites, this paper carries out dry shrinkage tests of different soil layers at the Zhouqiao site, reconstructs the study on cracking law of earthen soil under dry shrinkage-conditioned microstructure of site soil at different depths based on electron microscope pictures and finite element method, and explores the influence of different moisture content on the cracking of soil samples at the site. The results show that under conditions of dry shrinkage, the thickness of the soil layer has the greatest influence on the cracking of site soil samples. Due to the internal water loss and shrinkage of the soil sample, the thinner the soil layer, the more often the soil layer cracks first. The crack rate of the soil sample with a thickness of 1 cm is nearly three times higher than that of the soil sample with a thickness of 5 cm. Through numerical simulation analysis, it is found that the evolution process of soil fractures at the Zhouqiao site is mainly divided into the formation stages of initial stress field, single main fracture, secondary fracture and fracture network. The formation time of the secondary fracture is longer than that of the initial stress field and single main fracture, and the cracking of the upper soil sample is more serious than that of the lower soil sample. Under conditions of dry shrinkage, the particle arrangement of the soil sample is relatively loose, and there are many cracks inside, which provides evaporation and infiltration channels for water, forming unrecoverable weak pores, and finally, the cracks start to sprout at the weak points. The research results provide some reference for the disease mechanism and safety analysis of earthen sites.
Due to the effects of time and space, there is a continuous deterioration of the surface layers of earthen sites and a corresponding decline in soil stability. Evaluating the stability of these sites is very important for potential site restoration. In this study, we analyze, evaluate, and summarize the factors that adversely affect the ancient moat site in Liye, a town of Longshan County, Hunan Province, China, through on-site investigation, sampling, and testing. An X-ray diffractometer and a scanning electron microscope were used to analyze the chemical composition and microstructure of the soil sample of the trench, and the ABAQUS software was used to produce two-dimensional models of seriously damaged areas. Using the strength reduction method, we obtained the minimum safety factor of the trench under its natural state and after rainfall; thus, the stability of the trench was examined under different working conditions. Additionally, we evaluated the safety and stability performance of the more dangerous sections to provide a basis for the safety evaluation, protection, and repair of the trench. The results show that rain erosion, freeze–thaw cycles, and man-made damage are the primary factors contributing to a deterioration of the soil site. The safety factor of the trench is found to decrease with increases in water content; thus, water has an impact on the strength of the site wall. The wall soil has larger pores and more initial cracks than does the trench soil, which is easy to peel off. As a result, there is a high probability of a secondary deformation of the wall slope. Our results identify the real state of the existing site and provide both a basis for stability evaluation and a scientific formulation for restoration schemes.
In this paper, a method to control the lime reaction by different slaking conditions is proposed to reduce the occurrence of cracks in newly repaired earthen city walls. The effects and mechanisms of the slaking time (0 h, 12 h, 24 h, 48 h and 72 h), lime content (10%, 15% and 20%), and moisture content (14%, 18% and 22%) on the cracking and mechanical properties of lime soil were analyzed by the test results of surface cracks, triaxial compression, particle gradation, pH value, X-ray diffraction and scanning electron microscope. The results show that proper slaking of lime soil specimens can reduce surface cracks and improve mechanical properties. After 12 h of appropriate slaking, the crack rate of the lime soil with 20% content decreased by 97.13%, the cohesion increased by 20.27%, and the internal friction angle decreased by 11.27%. However, the mechanical properties decreased when the slaking time was too long. After 72 h of slaking, the cohesion of 20% lime soil decreased by 8.21% and the internal friction angle increased by 2.82%. Further analysis shows that the appropriate slaking conditions can regulate the reaction rate and alkali environment, control the lime produced cementitious substances, improve the particle gradation and further reduce the occurrence of surface cracks. These results provide a basis for the restoration technology of newly repaired earthen city walls.
Abstract P. ginseng is a precious traditional Chinese functional food, which is used for both medicinal and food purposes, and has various effects such as immunomodulation, anti-tumor and anti-oxidation. The growth year of P. ginseng has an important impact on its medicinal and economic values. Fast and nondestructive identification of the growth year of P. ginseng is crucial for its quality evaluation. In this paper, we propose a FC-CNN network that incorporates spectral and spatial features of hyperspectral images to characterize P. ginseng from different growth years. The importance ranking of the spectra was obtained using the random forest method for optimal band selection. Based on the hyperspectral reflectance data of P. ginseng after radiometric calibration and the images of the best five VNIR bands and five SWIR bands selected, the year-by-year identification of P. ginseng age and its identification experiments for food and medicinal purposes were conducted, and the FC-CNN network and its FCNN and CNN branch networks were tested and compared in terms of their effectiveness in the identification of P. ginseng growth years. It has been experimentally verified that the best year-by-year recognition was achieved by utilizing images from five visible and near-infrared important bands and all spectral curves, and the recognition accuracy of food and medicinal use reached 100%. The FC-CNN network is significantly better than its branching model in the effect of edible and medicinal identification. The results show that for P. ginseng growth year identification, VNIR images have much more useful information than SWIR images. Meanwhile, the FC-CNN network utilizing the spectral and spatial features of hyperspectral images is an effective method for the identification of P. ginseng growth year.
Combining both geological and petrophysical properties, a reliable rock typing scheme can be achieved. Two steps are included in rock typing. Step 1: rocks are classified into lithofacies based on core observations and thin sections; Step 2: lithofacies are further subdivided into rock types according to petrophysical properties such as MICP (Mercury Injection Capillary Pressure) and K-Phi relationships. By correlating rock types to electrofacies (clusters of log data), we can group the target formation into 12 rock types. Then it is possible to predict the distributions of rock types laterally and vertically using wireline logs. To avoid the defect of the classical J-function saturation model that includes permeability which is quite uncertain especially in carbonate rocks, a modified J-function was created and used in the paper. In this function, water saturation is simply expressed as a function of height above free water level for a specific rock type. Different water saturation models are established for different rock types. Finally, the water saturation model has been successfully constructed and verified to be appropriate.
The noise generated by transformers in operation contributes the vast majority of substation noise. In order to study the distribution of transformer core vibration noise, this paper built a vibration acoustic analysis model of 110kV series transformer, carried out the numerical analysis of transformer vibration and noise, and calculated and analyzed the magnetic flux density, core stress and sound field distribution of transformer core. The results show that with the increase of transformer capacity, the magnetic flux density of the iron core of the transformer increases, meanwhile the core stress and distribution of sound field is affected. The maximum total sound pressure level of 63MV.A transformer is 7.8dB higher than that of 40MV.A transformer.
Numerical simulations and laboratory tests on soil samples with compaction degrees of 94%, 96%, and 98% are carried out to study the laws of capillary water rising and control techniques. The silty soil samples are obtained from the Yellow River–flooded area of eastern Henan. The relation formulas between capillary water rising height and time are obtained through fitting. Results show that (1) the rising height gradually stabilized with the passage of time, reached about 130 cm on the 10th day, and eventually arrived at a maximum height of 285 cm; (2) the rising speed of capillary water was inversely proportional to the degree of compaction, especially when reaching the minimum rising height and speed with a compaction degree of 98%; and (3) the graded crushed stone, cement stabilized soil, and fiber cement stabilized soil effectively eliminated the rising of capillary water. Thus, properly increasing the compaction degree of the subgrade and adding a blocking layer of capillary water prevent the capillary water from rising, which improves the water stability of the subgrade.
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