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In China dry ports enter into a rapid development period now, however for many Chinese dry ports, the operation faces difficulties duo to inefficient logistics networks and cooperation relationship between dry ports and seaports. Focusing on the concession cooperation mechanism of seaports and dry ports, and the environmental constraints (carbon emissions and congestion cost), a bi-objective location-allocation MILP model for the sustainable hinterland-dry ports-seaports logistics network optimization is formulated, aiming at the system logistics costs and carbon emissions to be minimized. Moreover, for the cooperation mechanism of seaports to dry ports, a parameter called cooperation cost concession coefficient is proposed for the optimization model, and a new evaluation method based on the ordered weighted averaging (OWA) operator is used to evaluate it. Then a location-allocation decision-making framework for the hinterland-dry port-seaport logistics network is proposed. The innovative aspect of the model is that it can proposes a effective and environment friendly dry ports location strategic and also give insights into the connective cooperation relationships, and cargo flows of the network. A case study involving configuration of dry ports in Henan Province is conducted, and the model is successfully applied
Agricultural drainage is one of the leading contributors to agricultural non-point source (AGNPS) pollution in China. It is difficult to treat due to its dispersed nature. In recent years, although agricultural drainage water has been reused in agricultural production, its poor quality has limited its potential utilization. To optimize its reuse, we designed and tested a treatment system for agricultural-drained water compromising a vegetation buffer, slopes (plant filter), a water collection area, and a soil-retention wall in Hengxi town, Nanjing, Jiangsu Province, China. By exploiting the soil-vegetation buffer strips, nitrogen and phosphorus in the paddy field’s surface drainage are expected to be reduced dramatically. Test results suggest that after applying basal fertilizer, the removal rates of total nitrogen by the soil-vegetation buffer strips are 90.6% and 95.2% for controlled and conventional irrigation-drainage treatments, respectively. In addition, the removal rates of dissolved nitrogen are 92% and 90.7% (controlled and conventional), the removal rates of total phosphorus are 94.2% and 92.9%, and for dissolved phosphorus, the rates are 94.4% and 95%, respectively. These data indicate that drainage water from a paddy field that has been treated through the constructed system could reach the standard of National Class II with two irrigation-drainage methods, while for control treatments water quality can only reach Class V, which is severely contaminated. With this system, the reuse of agricultural water resources could be achieved, which will undoubtedly provide a great potential for agricultural water management in southern China, as well as achieving excellent overall ecological benefits.
Rice is a widely cultivated crop in China and needs a large quantity of water during its entire growth period. Many water-saving irrigation techniques have been developed and widely applied to conserve water in paddy fields in recent years. A controlled and mid-gathering irrigation (CMI) regime is one of them, of which the main feature is to maximize the use of rainwater different from the others. The objective of this study was to assess and verify the water conservation and nitrogen pollution reduction effects of CMI in comparison with a conventional irrigation (CVI) regime. Results showed that the CMI method had potential for water conservation by reducing total irrigation amount and irrigation frequency and making better utilization of rainwater during the rice growth stage. By making use of irrigation water more efficiently, CMI showed higher irrigation water use efficiency and rainfall use efficiency. CMI can also reduce nitrogen pollution emitted to the water system by reducing the pollutant discharge rather than the pollutant concentration during a storm event. However, the irrigation regime’s effect on pollutant loading reduction was not as significant as fertilizer according to experiment results. Thus, the controlled and mid-gathering irrigation regime was favorable for water conservation and reducing emissions of non-point source pollution.
A novel natural polymeric adsorbing material γ-cyclodextrin immobilized starch (CS-γCD) was prepared by introducing host functional molecule γ-cyclodextrin (γ-CD) into starch, using epichlorohydrin (ECH) as a cross-linking agent and sodium hydroxide as a catalyst, via the aqueous-phase synthesis method. The γ-cyclodextrin content in CS-γCD was up to 8.15% determined by the bromocresol green (BCG) hyperchromic spectrophotometric method. The structures of CS-γCD were characterized by infrared spectrum (FT-IR), ¹³C-nuclear magnetic resonance spectrum (¹³C-NMR), scanning electron microscope (SEM), x-ray diffraction (XRD), and gel permeation chromatography (GPC). We investigated the adsorption performances and kinetics of CS-γCD to three different kinds of dyestuff including methylene blue (MB), methyl purple (MP), and congo red (CR). The results showed the adsorbing capacities of CS-γCD to three kinds of dyes had obviously increased compared with native starch and diatomite, and the CS-γCD was also found to have a significant advantage in adsorption of macro-molecule dye such as CR over other adsorbing materials. The adsorption behaviors of CS-γCD on the three dyestuffs could be better described by a Langmuir model (R²>0.99), but also had relatively high correlation to Freundlich model. The pseudo second-order model could better describe the adsorption behaviors. The CS-γCD could be enzymolysised, while its degradation rate was much lower than native starch, which indicated that CS-γCD had a relatively higher structural stability and longer service life, these characters could be beneficial for the popularization and application of CS-γCD in fields of wastewater treatment and environment remediation.
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