Search

The study undertook a thin-layer hot air-drying experiment on rice, and an orthogonal testing approach was used to explore the drying characteristics under diverse conditions of hot air temperature, humidity, initial moisture content, airflow velocity, and tempering ratio. It compared the applicability of nine different accumulated temperature-nutritional index (protein, fat, starch) mathematical models in the hot air drying process of rice. The results showed that the experimental scheme was designed using Central- Composite design, and the parameter combination was optimized through a regression model to hot air temperature hot air temperature (T) at 38.5 ℃, humidity (RH) at 48.086%, initial moisture content (MC) at 19.82%, airflow velocity (V) at 0.70 m/s, and tempering ratio (TR) at 1.45. The relative error between the experimental results and the optimized results was 3.65%, and the relative error of the accumulated temperature-nutritional quality model was 5.92%. Through mathematical model fitting, it was found that the accumulated temperature-protein content was best fitted by the modified Page II model, while the accumulated temperature-fat content was best fitted by the Thompson equation. The accumulated temperature-amylose content was best fitted by the Midilli equation, and the accumulated temperature- amylopectin content was best fitted by the Weibull II equation. All models were highly significant. The optimized drying process maintained nutritional quality and improved drying efficiency. This study could provide a new approach for in-depth exploration of the mechanism of rice quality changes and lay a foundation for the subsequent development of intelligent control systems.

Ultraviolet (UV) irradiation is a non-thermal sterilization technique, and mercury vapor ultraviolet lamps currently serve as the primary equipment for food hygiene. However, due to some factors, the production and usage of mercury lamps gradually reduced. The inevitable trend has been their replacement by environmentally friendly and energy-efficient ultraviolet light-emitting diodes (UV-LED). This article, based on the principles of UV-LED light emission and the characteristics of multi-wavelength coupling applications, briefly reviewed the mechanisms of microbial inactivation. The factors affecting the inactivation effect (wavelength, UV dose and material characteristics), the sterilization effect of processed foods and the impact on the quality of some foods were explored. The aim was to provide a reference for optimizing the sterilization processes and equipment parameters of UV-LED in the field of food hygiene.

Corn is abundant in carbohydrate, protein, carbohydrates and other nutrients. However, because of its large embryo, it is easy to be infected by microorganisms and insects, which leads to the deterioration of corn quality. Therefore, the quality preservation and storage of corn is a challenge. So it is necessary to clarify the rule and change of corn storage quality. Corns with initial water content of 13.04%, 14.03% and 14.99% were taken as reasearch objects in this paper. During storage between 70% relative humidity and 20 ℃ (quasi-low temperature environment) , the changes laws of quality indexes such as bulk density, fatty acid value, germination rate, mold activity and microstructure of corn grain were studied emphatically. Otherwise changes of storage quality of corn at 70% relative humidity and 25 ℃ (room temperature environment) were compared. Therefore it can provide reference for safe storage of high-quality corn. The results demonstrated that the germination rate, fatty acid value and bulk density of corn under 20 ℃ were slower than those under 25 ℃. And they were in the suitable storage range in accordance with the national standard. The number of fungal spores increased sharply with the prolonged storage time. Meanwhile it showed significant correlation with the initial moisture content of corn. In other words, the number of fungal spores for corn under 14.99%w.b was stored for 120 d, and the safe storage periods of corn under 13.04%w.b, 14.03%w.b and 14.99%w.b were 180 d, 180 d and 100 d, respectively. The microstructure of corn kernel changed gradually during storage. It means the appearance changed from smooth and tidy to concave and convex folds. Furthermore, the arrangement of starch granules changed from tight structure to sparse and disordered structure. The main factors of corn quality and microstructure change were corn initial water content and storage time, during storage at quasi-low temperature environment. So the change laws of corn storage quality with different water content were explored, so as to provide new research perspective for maize post-harvest to reduce loss and guarantee qualtiy.

The current control methods in the grain drying process mainly focus on ensuring uniform moisture content, energy saving, and emission reduction. However, precise control of drying quality remains a bottleneck problem. To address issues such as strong coupling, nonlinearity, and difficult quality control in the grain drying process, this paper proposes the utilization of long and short-term memory neural network (LSTM) coupled with model predictive control (MPC) based on previous studies. This combined controller was applied to regulate the grain drying process according to a reference diagram for high-quality rice targeted regulation during the drying process. The simulation environment was used to compare the control accuracy of these two controllers. The effectiveness of system control was evaluated through continuous rice drying tests conducted both before and after the incorporation of the process reference diagram. Results demonstrate that compared to conventional PID controller, the LSTM-MPC controller exhibits stronger robustness and faster response speed. Furthermore, by incorporating the process reference diagram into control decisions, visualization of the drying process quality index can be achieved while significantly improving overall drying quality levels.

The supervision of grain reserves is a major event of national food security. China has built the largest grain internet of things in the world. Although there are still have some problems such as low data quality, low utilization rate, and serious information islands, it still provides a basis for conducting digital supervision on grain reserves. On the basis of studying the multi-fields coupling and biological theory in stored grain ecosystems, the author team proposed the continuity, periodicity and coordination principles of the digital supervision of grain reserves, and further proposed 7 intelligent strategies using the big data analysis of grain situation and the intelligent analysis method of 10 modes of grain storage in the granary. In combination with the application cases of 10 provinces that participated in the policy oriented inventory check of grain reserves organized in 2018, this paper analyzes the principle of digital supervision of grain reserves and 7 intelligent methods, which will accelerate the transformation and large-scale promotion of relevant technological achievements, and accelerating the construction of a high-quality technical system for grain reserves supervision. This digital intelligence method will promote the transformation of grain reserve management from “human management" to "technology management”, and let data play its due role in grain reserve decision-making and management.

The innovative development of green technology is the permanent scientific research topic in the field of grain storage, and the controlled atmosphere is one of the green grain storage technologies. This paper carried out the research on the storage technology of high-quality indica rice in the fifth ecological area of grain storage (medium temperature and high humidity) by air-regulating agent. The concentration of oxygen, temperature and relative humidity of the storage environment were monitored, and the quality of high-quality indica rice was also evaluated. The results showed that the technology of air-regulating could effectively delay the quality deterioration of rice. Compared with the controlled group, the experiment group can maintain the concentration of oxygen in the confined space below 0.1% and the relative humidity at 70% during the 5-month storage period. The moisture content of the controlled atmosphere group was 0.98% higher than that of the controlled group. The fatty acid value was 1.34 mg (KOH)/100 g lower than that of the controlled group, while the freshness was 7 points higher than that of the controlled group. The above results showed that the air-regulating agent can adjust and control the oxygen concentration and relative humidity in the confined space according to the demand, which could achieve the purpose of preserving the quality and freshness of grain. It is a green, low-carbon and fresh-reserving new grain storage technology.

The air-film reinforced concrete spherical silo (hereinafter referred to as the air-film spherical silo) is a new type of storage structure. In order to explore the effect of the air-film spherical silo, the paper takes the first air-film spherical silo in China as a research object, and takes the wheat grain pile as the research target. The grain temperature quality, quality index, toxin and other indicators were tested and analyzed. The results showed that, during the grain storage process, the wheat grain heap in the air film spherical silo had no pests, no mildew, and all quality indicators met the suitable storage standard. The grain situation was stable and the quality was good, the air-film spherical silo is a new type of warehouse suitable for grain quality and safe storage.

The Chinese government has announced the goal of carbon peak and carbon neutrality, demonstrating China's responsibility as a major country to actively respond to climate change and promote sustainable development of the world. In recent years, state-owned grain storage enterprises have vigorously promoted energy saving, carbon reduction, and efficient development in upgrading grain storage facilities and equipment, innovating grain storage technology and, strengthening standardized storage management. Combined with the current situation of the development of state-owned grain storage enterprises, the concept of "carbon neutral grain" was proposed firstly in the paper. Under the goal of carbon neutrality, state-owned grain storage enterprises should do a good job of “subtraction” of low carbon operation as well as actively utilize “addition” of green energy such as photovoltaic power generation, taking the lead to realize their own low carbon development and lead the industry as an example.

The air-film reinforced concrete spherical silo (hereinafter referred to as the air-film spherical silo) is a new type of storage structure. In order to explore the effect of the air-film spherical silo in a storage period, this paper takes the first air-film spherical silo in China as a research object and the wheat grain pile as the research target to reproduce the distribution of temperature field cloud map in the radial and vertical plane of wheat in the storage period by numerical fitting. Results showed that the air-film spherical silo had the characteristics of low silo temperature and average grain temperature. A huge and stable “cold core” formed inside the grain pile, effectively inhibiting the reproduction of pests. Therefore, the grains can safely pass the summer without the use of chemical fumigation in a whole grain storage period, which has a positive effect on promoting the development of low-temperature green grain storage technology.

Based on the theory of grain storage ecosystem, multi-field coupling and ventilation window, the dynamic analysis software of grain condition cloud map is researched and developed by WU model,sinusoidal model of grain temperature change, heat and mass transfer model and related empirical model.By drawing visual dynamic cloud maps of grain condition, combining with the warehouse types, grain storage characteristics and regional environment, the state and change of grain storage can be analyzed and predicted,then the quantity and quality can be distinguished.In addition, the software system has been applied and improved in the national warehouse inventory in 2018 and 2019.It provides effective technical support and tool services for the realization of the whole process of grain storage quantity and quality safety management.

In recent years, the government has introduced the PPP model to promote the construction of charging infrastructure. However, due to the complex project composition and uncertain profitability, it is still difficult to promote the PPP project of charging infrastructure. From the perspective of charging pricing, this paper analyzes the factors influencing the charging pricing of charge infrastructure PPP project, establishes the charging pricing model based on the principle of system dynamics, and runs simulation by using Vensim software. This paper analyzes the simulation results from the perspective of project investment return and consumer utility. In addition, sensitivity analysis is used to determine the key factors influencing the charge pricing. On this basis, some suggestions are put forward to provide references for optimizing the charging price of charging infrastructure PPP projects in China. [ABSTRACT FROM AUTHOR]