327 research outputs found

    Ball-milling properties and sintering behavior of Fe-Tm 2 O 3 mixture powders

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    Abstract(#br)Aimed at the existing problems of current neutron absorbers that were used in control rods to safely operate a nuclear reactor, new type of Fe-based Tm 2 O 3 composites and Fe-based TmFeO 3 composites, which were synthesized from the Fe-25.68 wt.%Tm 2 O 3 mixture powders by ball milling, cold isostatic pressing and sintering, were designed as next generation neutron absorbers in the present work. During ball milling, Tm 2 O 3 was fined, nano-crystallized, amorphized and then dissolved into Fe crystal lattice to form Fe (Tm, O) nanocrystalline solid solution. The effect of sintering temperature and oxygen content at sintering environment on the phases of the sintered bulks were researched, and the corresponding mechanism was discussed. Nanoscale TmFeO 3 and Tm 2 O 3 particles were distributed in the sintered bulk matrix. The microhardness, compression strength, and the coefficients of thermal expansion of the bulks sintered at different conditions were measured and discussed. The coefficient of linear expansion and compressive strength increased with increasing ball-milling time. The microhardness increased with increasing sintering temperature when the temperature was lower than 1200 °C. Meanwhile, the microhardness and compressive strength of Fe-based Tm 2 O 3 composites were larger than that of Fe-based TmFeO 3 composites, opposite for the coefficients of thermal expansion

    Grape Drying: Current Status and Future Trends

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    With high moisture and sugar content, fresh grapes respire and transpire actively after harvest, which contribute to quality loss. Drying can process grapes into raisins for longer shelf-life as well as dehydrated grapes, which can be used for wines or juice production. The pre-treatments, drying method and drying conditions, can significantly influence the quality of final products. In this chapter, firstly, different pre-treatments as a necessary operation previous to the drying of grapes into raisins is introduced. These pre-treatments include chemical pre-treatment, physical pre-treatment, and blanching. In addition, the quality and drying characteristics of different pre-treatments is summarized too. Secondly, the current status of different technologies for grape drying and their effects on drying kinetics and quality attributes of seedless grapes are described to highlight the advantages and disadvantages of each drying method. These drying methods include the traditional open sun drying, shade drying, hot-air drying, freezing drying, microwave drying, as well as the vacuum impulsed drying. Thirdly, influences of drying on bioactive substances (flavonoids, phenolics, anthocyanin, and resveratrol) and antioxidant capacity of grape by-products including seed, skin, stem, and stalk are also examined. Finally, the future research trends of grape and its by-product drying are indentified and discussed

    Energy Conservation Potential Assessment Method for Table Grapes Supply Chain

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    Energy consumption is one of the most crucial issues in the table grapes supply chain. However, the potential for energy conservation assessment is still limited because of the complexity of the process. The aim of this paper is to propose an energy conservation potential assessment method in order to increase energy consumption transparency and help managers take appropriate energy conservation measures to reduce the energy consumption in the table grapes supply chain. The conservation potential assessment in three kinds of the supply chain modes (the normal chain, the cold insulation chain and the cold chain), were realized by integrating the actual energy consumption investigated with the unified energy consumption per unit energy factor that represents the energy consumption throughout the entire product lifecycle. According to the comprehensive analysis of the energy consumption compared with the energy conservation potential in actual supply chain of table grapes, the proposed energy conservation potential assessment method could provide a unified method for evaluating the energy conservation potential in different supply chain mode of table grapes. The energy conversation potential in cold insulation chain, which was about 0.985, was the highest and that in cold chain, which was about 0.935, was the smallest. However, the cold chain was still the optimal supply chain for the table grapes because of the characteristics of the longest storage shelf life and the lowest quality decay, and the cold chain energy consumption would be further reduced by adopting the more advanced refrigeration and preservation technologies. The proposed energy conservation potential assessment method could be extended for other supply chain applications to evaluate their own energy conservation potential, and thus, reduce their energy consumption

    Carbon Footprint Constrained Profit Maximization of Table Grapes Cold Chain

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    Low-carbon production is one of the dominating issues in the sustainable development of the food industry with high energy consumption, especially in the table grapes cold chain. The aim of this paper is to propose a profit maximization strategy of table grapes cold chain by integrating the carbon footprint to improve the low-carbon production and sustainability of the cold chain system. The carbon footprint was evaluated by life cycle assessment (LCA) in entire cold chain system of table grapes, and the economic order quantity (EOQ) model was used to develop the profit maximization model with minimal carbon footprint and to maintain the optimal balance between stock and cost. The profit optimization performance, the sensitivity performance and the influencing factors of the decay rate, the carbon emission price, and the distance and carbon emission coefficient in refrigerated transport were analyzed according to the profit maximization model and the inventory data in actual cold chain investigated. The sensitivity performance analysis illustrated that the selling price had the highest sensitivity, and the carbon emission coefficient in storage had the lowest sensitivity. The comprehensive analysis results indicated that there is an optimal combination point between the economy and environment in actual cold chain, which not only reduced the carbon emission, but also had minimal impact on the profit in cold chain. The enterprises should integrate the carbon footprint cost into the profit maximization once the carbon emission tax is levied. The proposed strategy of the profit maximization with carbon footprint constraint is also suitable for improving profit maximization of other low-carbon supply chain applications

    Environmental Efficiency of Chinese Open-Field Grape Production: An Evaluation Using Data Envelopment Analysis and Spatial Autocorrelation

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    Grape production is associated with some negative environmental externalities. However, they are not considered in the traditional data envelopment analysis (DEA) efficiency assessment models and the research literature. Hence, the assessment results cannot correctly reflect the technical efficiency level of open-field grape production. We measured the environmental efficiency of China’s open-field grape production under the constraint of carbon emissions using the slacks-based measure (SBM) model, including the undesirable outputs. In addition, spatial relations of environmental efficiency in different open-field grape production areas in China were evaluated by adopting spatial econometric methods. The results indicate that the average environmental efficiency score of grape production in China is at a low level of 0.651. Overall, the average environmental efficiencies in southern, southwest, and northeast regions are lower than the average levels, which implies the imbalance in economic outputs, resource consumption, and environmental efficiency in open-field grape cultivation. Moreover, the spatial autocorrelation results show that the environmental efficiency of grape production has obvious continuity in neighboring regions and spatial correlation
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