The microcosm tests were done to estimated the HRT (Hydraulic Retention Time) and removal efficiency of reflowing treatment of the landfill leachate collected from Dalian Maoyingzi Municipal Solid Waste Landfill, which contained high levels of COD (Chemical Oxygen Demand, 38400 mg/L) and SS (Suspended Solids, 650 mg/L) by the reed constructed wetland located in the south area of Dalian Jiaotong University. The results showed that: (1) The HRT in nature soil cuboids were significant shorter than those in sieved soil cuboids (P<0.01); (2) The removal efficiency among the output water with the trend as follows: Preferential flow (53.9%)<Percolating water (59.2%)<Reflowing water (63.3%); (3) The COD and SS were decreased from 38400 and 650 mg/L to 14080 and 213 mg/L by the way of reflowing with the HSL (Hydraulic Surface Loading) of 0.16 m 3 /(m 2 ·d) by reflowing (Removal efficiency: COD: 63.3%; SS: 67.3%).
Carbon emissions cost is a potential effective measure to restrict hydrocarbon pollution in the international shipping trade. The minimization of the total cost is pursued by ship operators, whereas voyage cost is increasingly involving the replacement of clean fuel and changing the cost of the shipping route. A flexible optimization method focusing on maximizing the total profit is developed in terms of sailing speed optimization and single port skips integrate carbon emission influence. An actual ocean shipping route from Shanghai to Rotterdam is applied to validate the effectiveness of the proposed models. The results have shown that the shipping route profit is volatile along with the sailing speed and the number of port calls. However, the profit will be maximized when applying the single port skip and will slow down the sailing speed at the same time. The demand of planned skip port can be supported by a short line container. A system composed of ocean container liner and short line container can improve the profit by 4.05% and reduce the carbon emission by 19.70%. Furthermore, sensitive results show that the profit is less affected by the changing of the carbon emission cost. A small size container has enough ability to solve the short transportation demand in adjacent ports and convert extraberthing cost into profit. These findings can provide reliable support for the shipping route decision process considering future carbon emission costs.
Housing unit is studied as cell in this paper. The cell model analyzes structure and usage of each primary apartment and room of a housing unit in a view of a biological cell. Individual human person is abstracted as ATP and electron in this model, and it is demonstrated that human has the dominant impact on urban management and social administration as an electron in a living organism.
Considering the unobserved spatial heterogeneity, this study aims to build a Bayesian spatial multinomial logistic (BSMNL) model by utilizing the geographic information from historical maritime accidents. The proposed BSMNL model can be applied to investigate the determinants of human errors involved in maritime accidents. Compared to the traditional multinomial logistic (MNL) model, the proposed BSMNL model produces a more accurate estimate of the effects of environmental and accident factors on the occurrence likelihood of human errors in maritime accidents. Results show that accidents involving cargo and container ships; tankers carrying liquefied natural gas (LNG), liquefied petroleum gas (LPG), or oil; and fishing vessels are more likely to be associated with human errors. Further, one important finding is that the involvement of fishing vessels significantly increases the occurrence probability of both negligence errors and judgment or operational errors. In addition, the occurrence likelihood of human errors is generally higher in springtime, conditions of poor visibility, the absence of strong winds or waves, and the moored or docked status.
Carnivore communities are extremely important for maintaining the structure/function of ecosystems. Exploring the carnivore coexistence can provide the data needed for the development of effective conservation strategies for endangered species. We aimed to (1) reveal the dietary composition of a carnivore community that inhabits the Everest region by analyzing molecular diets, (2) assess activity patterns by analyzing camera-trapping records. Dietary analysis revealed 22 food MOTUs of 7 orders and 2 classes. Snow leopard and wolf mainly preyed on ungulate mammals (%PR = 61%, 50%), while lynx and red fox mainly consumed small mammals (%PR = 62%, 76%). Higher dietary overlap (Pianka’s index = 0.95 ~ 0.97) was observed between similar-sized predators (snow leopard versus wolf, lynx versus fox); and there was no dietary difference between them (P > 0.05). Lower dietary overlap (Pianka’s index = 0.53 ~ 0.67) was observed between predators with large body size difference (snow leopard versus lynx, snow leopard versus red fox, wolf versus fox); and dietary difference was significant (P < 0.01), indicating the existence of dietary partitioning. In activity pattern analysis, predators exhibited higher temporal overlap with the more frequently consumed prey species, indicating that predator activity can be regulated by prey availability. Snow leopard and wolf had the higher activity overlap (Δ = 0.87) suggesting the lack of temporal partitioning. Red fox had the lower coefficients of overlap with snow leopard and wolf (Δ = 0.60, Δ = 0.59), suggesting that fox temporally avoid snow leopard and wolf slightly. We revealed the coexistence mechanisms of a carnivore community in the Everest region, by confirming that sympatric coexistence was facilitated by both dietary and temporal partitioning. These results will help to increase understanding of carnivore communities, and provide the scientific foundation for the conservation of threatened species in the Mount Everest region.
Due to the complexity of the transmission tower structure and the correlation between wind and ice loads in the actual project, it is difficult to analyze the reliability of transmission towers with traditional methods. To solve this problem, the unscented transformation (UT) principle is presented concisely and used in the reliability analysis of transmission towers in this paper. Moreover, the finite element model of the target transmission tower is created. The reliability indices of the transmission tower under various loading cases are evaluated using UT and analyzed relative to the outcomes of the Monte Carlo method (MCS). Lastly, by analyzing and validating a wine-cup shape tangent tower, the simulation results show that the UT yields reliability indices with less than 6% relative error compared with MCS results for the transmission towers with lower reliability, which are more important in engineering. Variations in error caused by the change in correlation coefficients among variables are small. Consequently, the efficiency of calculations is improved by the UT-based reliability calculations for transmission towers in the case of correlated variables, which better meet engineering application requirements. It is proved that the method of reliability analysis for transmission towers based on the UT is applicable.
In the information age, people are faced with new problems that the traditional exchange guaranteed by face-to-face trust in the past in the supply chain needs new solutions in today's networked electronic transactions with emerging technologies. In the context of economic globalization, multinational enterprises evolved from small and medium-sized enterprises should develop new strategic responses to deal with the complexities of managing operations separated by the barriers of distance, language, time, and culture. On the basis of studying the developing process of cross-border enterprises, this paper analyzes the problems of electronic transactions, discusses the innovation of cross-border e-commerce business model based on Blockchain technology (BT), builds a BT based enterprise framework system, and provides solutions to the problems of trust, customs supervision, cross-border payment, cross-border logistics and cross-border data flow encountered by enterprises. It elaborates a management mode from operating mechanism for SMEs to engage in international business activities in the new age.
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