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The purpose of this research is to microencapsulate the ARA oil by spray-drying using different wall materials. A systematic investigation was implemented to characterize the effects of microcapsules on the structure, physical and chemical properties, and stability. The ARA microcapsules were used as the core material, where Whey protein (W), Whey ProteinGlucose (WG), and Whey Protein-Glucose Syrup-Lactose (WGL) were used as the wall materials. An analysis was made on the encapsulation efficiency, water content, solubility, bulk density, angle of repose, particle size distribution, micromorphology, oxidation stability, and thermal stability of the microcapsules. The properties of the microcapsules were compared from different wall materials. The results showed that the higher encapsulation efficiency of WGL was 98.64%, indicating a significant difference between W and WG (P＜0.05). The encapsulation efficiency was increased and the embedding effect of microcapsules was good. The WGL was measured to observe a water content of 2.85% and a bulk density of 0.54 g/mL. There was no significant difference among the three kinds of ARA oil microcapsules. Microcapsule powders that are obtained in this research study were very stabile and compressible.The solubility of WGL was higher and the angle of repose of WGL was lower, which were significant differences between W and WG (P＜0.05). The solubility of WGL reached 89.83%, it was increased and the quality of microcapsules was good. The angle of repose of WGL was 35.87°, which angles of repose of WGL were 7.36° and 4.38° lower than those of W and WG. As such, the smaller the angle of repose of the WGL was, the smaller the frictional force, and the better the fluidity was, the larger particle size was, indicating the normal distribution and a narrow region. The physicochemical properties of WGL were superior to W and WG, which was beneficial to the storage stability of microcapsules. The microcapsule product shared the spherical microstructure, free-cracks, free-pores, dense structure, fullness, and complete particle morphology, which basically achieved the intended purpose of embedding. The iodine titration was used to determine the peroxide values of W, WG, and WGL. Specifically, the peroxide values of WGL increased from 2.42 to 19.92 and 32.75 mmol/kg at 25 ℃ and 50 ℃, respectively. The peroxide values of WGL were significantly lower than those of W and WG (P＜0.05), indicating that WGL with higher oxidative stability. The accelerated storage test of the ARA oil after embedding showed that the WGL improved the oxidative stability of ARA oil. The wall material of WGL was better than those of W and WG for embedding ARA oil, which hindered the influence of external conditions on ARA oil and isolated oxygen, thus slowing down the oxidation rate. The reason was the dense and void-free structure of the WGL. Therefore, the oxidative deterioration of ARA oil microcapsules was effectively delayed during storage and prolonged the shelf life. The maximum melting temperature and mass retention rate of WGL were 107 ℃ and 27.55 %, respectively, according to the differential scanning calorimetry and thermal gravity analysis. The WGL shared better thermal stability than W and WG. Therefore, there were higher temperatures and energy required for the phase transition of the WGL, indicating better thermal stability. The WGL can be expected to store the stability of microcapsules at room temperature. In conclusion, the properties of WGL are better than those of W and WG, indicating a better embedding and protective effect on ARA microcapsules. The finding can also provide a strong reference for the selection of the appropriate wall materials to encapsulate ARA microcapsules. [ABSTRACT FROM AUTHOR]

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The quality and safety of iced aquatic products have been the key steps to improve the benefits in the aquatic industry. However, there are three challenges in the traditional evaluation of the freshness of aquatic products, including the complicated operations, samples destruction, and low efficiency. It is highly urgent to find an effective way for the aquatic products in a cold chain system. Taking the iced pomfret as a research object, this study aims to propose a novel computer vision for the evaluation of the freshness using an improved VGG-19. The dataset collection and algorithm design were also utilized as follows. 1) The image dataset of the freshness grade was established to integrate the environmental factors and the Total Volatile Basic Nitrogen (TVB-N) in the cold chain system. Specifically, the image data was collected, according to the physicochemical index TVB-N of freshness at a constant temperature of 0 ℃, with days as the unit of time. As such, a total of 2 387 image samples were collected after 30 days. The freshness level of pomfret was then divided into three categories, such as the first-class, qualified, and unqualified, according to the standard regulations of SC/T 3103-2010 “Fresh and Frozen Pomfret”. 2) Deep learning has developed rapidly in recent years. Among them, Convolutional Neural Networks (CNN) can automatically learn a large number of samples and extract features of interest, which are widely used in various image classification tasks. Four CNN models were selected for the classification of the freshness, including AlexNet, VGG-16 (visual geometry group 16), VGG-19 (visual geometry group 19), and ResNet-50 (Residual Network-5). The weights and biases of the pre-training model were fine-tuned to improve the generalization of the model. After that, the VGG-19 with the transfer learning was selected as the main model of the classification. More importantly, the dataset of freshness classification was designed for the three-classification task. The fully connected layers were modified to save time and space costs for the higher efficiency and accuracy of the network. The reason was that the three-layer fully connected layer of traditional VGG-19 presented a complex structure with too many parameters. After modification, the improved network was utilized to rapidly and accurately classify the features. After comparison, the [4 096, 4 096, and 1 000] three-layer fully connected structure of VGG-19 was improved to the [128, 3] two-layer fully connected structure. The experimental results show that the improved model achieved a 99.79% accuracy of classification with less time and space, where the parameters of the fully connected layer were reduced by 97%, and the space was reduced by 443.9 MB. In addition, a class activation mapping was introduced to visualize the freshness grading, thereby understanding the grade judgment of freshness in the model. Subsequently, 18 pomfret pictures were selected with the different freshness levels, regions, and orientations. A confusion assessment method (CAM) was also applied to generate a visual heat map for subsequent experimental analysis. Consequently, the improved CNN model can be expected to accurately predict the freshness level with a specific basis for the judgment. Among them, the most effective information for the freshness evaluation was the abdominal characteristics of pomfrets, no matter where the pomfret was placed. This improved model was also suitable for the various iced aquatic products, particularly when it is difficult for the naked eye to determine the freshness level in the aquatic industry. [ABSTRACT FROM AUTHOR]

The silo has the advantages of small area, good sealing conditions, low circulation costs, low cost and etc. It is currently the leading warehouse type of grain storage in China. Most silos still use gravity-based discharging methods, however, arches often form during silo discharging, it causes the pressure that should have been taken from the bottom of the warehouse to the wall of the warehouse. As a result, cracks may form in the silo walls causing serious damage. In addition, when there are workers above the grain surface or when the arch is manually broken, the collapse of the arch will not only result in personal injury or death of the grain surface staff, but also may damage the warehouse structure and facilities in the warehouse. In recent years, with the development of building technology, the silo volume has been continuously increasing, the diameter and height of the silo have also become larger and larger, and the related accidents caused by unloading and arching silos have also become more frequent Silo arch accidents in Daqing 2013, Lanxi 2015, in Heilongjiang province, and in Jing County in 2016 in Anhui province, for example, have resulted in the destruction of some silo facilities and casualties. Existing studies have shown that silo unloading and arching are closely related to the internal and external friction of grain. However, in those studies, a single circular particle is used in the current discrete element simulation. The real contact area of simulated grain is much smaller. As such, the simulation cannot objectively reflect the grain of the unloading process. The frictional situation is also more difficult to restore the mesoscopic dynamic process of unloading grain arching. In this paper, based on the existing PFC3D discrete element program, the micro particle simulation dust with larger viscosity coefficient was added to create an improved particle for the defect that the internal friction force of the circular particle in the discrete element simulation was smaller than that in the real grain. We used geometric methods in the structural mechanics model to determine the contact between the circular particles and derives the force-displacement relationship between the basic units. Based on typical accident cases and laboratory test results, the established particle structure mechanics model was used to simulate the force-displacement relationship between circular large particles and between small round particles and walls in the dynamic process of unloading grain and arching. The displacement map of shear stress and its stress characteristic curve were basically consistent with the experimental results. By using this model, the dynamic meso-mechanism of unloading and arching silos can be objectively reflected. The improved particle structure mechanics model proposed in this paper can not only be used to simulate the unloading and arching mechanism simulation, but also has certain reference value for the simulation of the characteristics of loose particles flow and the mechanism of the interaction between the bulk and the silo wall. [ABSTRACT FROM AUTHOR]

The silo has the advantages of small area, good sealing conditions, low circulation costs, low cost and etc. It is currently the leading warehouse type of grain storage in China. Most silos still use gravity-based discharging methods, however, arches often form during silo discharging, it causes the pressure that should have been taken from the bottom of the warehouse to the wall of the warehouse. As a result, cracks may form in the silo walls causing serious damage. In addition, when there are workers above the grain surface or when the arch is manually broken, the collapse of the arch will not only result in personal injury or death of the grain surface staff, but also may damage the warehouse structure and facilities in the warehouse. In recent years, with the development of building technology, the silo volume has been continuously increasing, the diameter and height of the silo have also become larger and larger, and the related accidents caused by unloading and arching silos have also become more frequent Silo arch accidents in Daqing 2013, Lanxi 2015, in Heilongjiang province, and in Jing County in 2016 in Anhui province, for example, have resulted in the destruction of some silo facilities and casualties. Existing studies have shown that silo unloading and arching are closely related to the internal and external friction of grain. However, in those studies, a single circular particle is used in the current discrete element simulation. The real contact area of simulated grain is much smaller. As such, the simulation cannot objectively reflect the grain of the unloading process. The frictional situation is also more difficult to restore the mesoscopic dynamic process of unloading grain arching. In this paper, based on the existing PFC3D discrete element program, the micro particle simulation dust with larger viscosity coefficient was added to create an improved particle for the defect that the internal friction force of the circular particle in the discrete element simulation was smaller than that in the real grain. We used geometric methods in the structural mechanics model to determine the contact between the circular particles and derives the force-displacement relationship between the basic units. Based on typical accident cases and laboratory test results, the established particle structure mechanics model was used to simulate the force-displacement relationship between circular large particles and between small round particles and walls in the dynamic process of unloading grain and arching. The displacement map of shear stress and its stress characteristic curve were basically consistent with the experimental results. By using this model, the dynamic meso-mechanism of unloading and arching silos can be objectively reflected. The improved particle structure mechanics model proposed in this paper can not only be used to simulate the unloading and arching mechanism simulation, but also has certain reference value for the simulation of the characteristics of loose particles flow and the mechanism of the interaction between the bulk and the silo wall. [ABSTRACT FROM AUTHOR]

The silo has the advantages of small area, good sealing conditions, low circulation costs, low cost and etc. It is currently the leading warehouse type of grain storage in China. Most silos still use gravity-based discharging methods, however, arches often form during silo discharging, it causes the pressure that should have been taken from the bottom of the warehouse to the wall of the warehouse. As a result, cracks may form in the silo walls causing serious damage. In addition, when there are workers above the grain surface or when the arch is manually broken, the collapse of the arch will not only result in personal injury or death of the grain surface staff, but also may damage the warehouse structure and facilities in the warehouse. In recent years, with the development of building technology, the silo volume has been continuously increasing, the diameter and height of the silo have also become larger and larger, and the related accidents caused by unloading and arching silos have also become more frequent Silo arch accidents in Daqing 2013, Lanxi 2015, in Heilongjiang province, and in Jing County in 2016 in Anhui province, for example, have resulted in the destruction of some silo facilities and casualties. Existing studies have shown that silo unloading and arching are closely related to the internal and external friction of grain. However, in those studies, a single circular particle is used in the current discrete element simulation. The real contact area of simulated grain is much smaller. As such, the simulation cannot objectively reflect the grain of the unloading process. The frictional situation is also more difficult to restore the mesoscopic dynamic process of unloading grain arching. In this paper, based on the existing PFC3D discrete element program, the micro particle simulation dust with larger viscosity coefficient was added to create an improved particle for the defect that the internal friction force of the circular particle in the discrete element simulation was smaller than that in the real grain. We used geometric methods in the structural mechanics model to determine the contact between the circular particles and derives the force-displacement relationship between the basic units. Based on typical accident cases and laboratory test results, the established particle structure mechanics model was used to simulate the force-displacement relationship between circular large particles and between small round particles and walls in the dynamic process of unloading grain and arching. The displacement map of shear stress and its stress characteristic curve were basically consistent with the experimental results. By using this model, the dynamic meso-mechanism of unloading and arching silos can be objectively reflected. The improved particle structure mechanics model proposed in this paper can not only be used to simulate the unloading and arching mechanism simulation, but also has certain reference value for the simulation of the characteristics of loose particles flow and the mechanism of the interaction between the bulk and the silo wall. [ABSTRACT FROM AUTHOR]