Two kinds of solar thermal power generation systems (trough and tower) are selected as the research objects. The life cycle assessment (LCA) method is used to make a systematic and comprehensive environmental impact assessment on the trough and tower solar thermal power generation. This paper mainly analyzes the three stages of materials, production and transportation of two kinds of solar thermal power generation, calculates the unit energy consumption and environmental impact of the three stages respectively, and compares the analysis results of the two systems. At the same time, Rankine cycle is used to compare the thermal efficiency of the two systems.
Cucumis sativus is an important vegetable crop in the world. Agrobacterium mediated transgenic technology is an important means to study plant gene function and variety improvement. In order to further accelerate the transgenic research and breeding process of cucumber, aiming at the Agrobacterium mediated genetic transformation method of cucumber, this paper expounds the research progress and existing problems of Agrobacterium mediated transgenic cucumber from the aspects of influencing factors of cucumber regeneration ability, genetic transformation conditions and various added substances in the process, and prospects the future of improving the efficiency of cucumber genetic transformation and the application of safety screening markers, in order to provide reference for cucumber stress resistance breeding and fruit quality improvement.
This paper reviews and compares the opportunities and challenges in terms of port and intermodal development in China and India—the two fast-growing economic giants in the world. The study analyzes the future direction of these two countries’ port-hinterland intermodal development from the sustainability perspective. Both China and India face some major opportunities and challenges in port-hinterland intermodal development. The proposal of the Silk Road Economic Belt and the 21st-century Maritime Silk Road, also known as the Belt and Road Initiative (BRI), offers plentiful opportunities for China. A challenge for China is that its development of dry ports is still in the infancy stage and thus it is unable to catch up with the pace of rapid economic growth. As compared with China, India focuses more on the social aspect to protect the welfare of its residents, which in turn jeopardizes India’s port-hinterland intermodal development in the economic sense. The biggest challenge for India is its social institution, which would take a long time to change. These in-depth comparative analyses not only give the future direction of port-hinterland intermodal development in China and India but also provide references for other countries with similar backgrounds.
The expansion of road networks, taken place during the last decades, was driven by technological progress and economic growth. The most innovative products of this trend—modern motorways and international road corridors—provide an excellent level of service, traffic safety and necessary information to travelers. However, despite this undeniable progress, major impediments and respective challenges to road authorities and operators still remain. The present paper analytically presents the main current challenges in the road engineering field, namely: a) financing new projects, b) alternative energy resources, especially renewable energy, c) serviceability, including maintenance of road infrastructure, traffic congestion and quality of the network, d) climate change hazards due to greenhouse gas emissions increase, e) environmental impacts, f) safety on roads, streets and motorways, and g) economy and cost-effectiveness. In each country and over each network, challenges and concerns may vary, but, in most cases, competent authorities, engaged in road development policies, have to deal with most of these issues. The optimization of the means to achieve the best results seems to be an enduring stake. In the present paper, the origin and the main features of these challenges are outlined as well as their tendency to get amplified or diminished under the actual evolving economic conditions worldwide, where growth alternates with crisis and social hardship. Moreover, responses, meant to provide solutions to the said challenges, are suggested, including research findings of Aristotle University and innovative technological achievements, to drive the transition to a more sustainable future.
Based on first-principles methods, the authors of this paper investigate spin thermoelectric effects of one-dimensional spin-based devices consisting of zigzag-edged graphene nanoribbons (ZGNRs), carbon chains and graphene nanoflake. It is found that the spin-down transmission function is suppressed to zero, while the spin-up transmission function is about 0.25. Therefore, an ideal half-metallic property is achieved. In addition, the phonon thermal conductance is obviously smaller than the electronic thermal conductance. Meantime, the spin Seebeck effects are obviously enhanced at the low-temperature regime (about 80K), resulting in the fact that spin thermoelectric figure of merit can reach about 40. Moreover, the spin thermoelectric figure of merit is always larger than the corresponding charge thermoelectric figure of merit. Therefore, the study shows that they can be used to prepare the ideal thermospin devices.
The porous carbon/Ni nanoparticle composite was prepared by a freeze-drying method using NaCl as the template. It was applied in the effect of the concentration, adsorption time, and temperature of adsorption on the adsorption behavior. The kinetic model and the adsorption isothermic fitting results show that the adsorption behavior fits with the pseudo-secondary dynamics and the Langmuir isothermal model, indicating that the adsorption process is monolayer adsorption. Thermodynamic results indicate that the adsorption process is spontaneous physicochemical adsorption. The fitting showed that the porous carbon/Ni nanoparticle composites reach 217.17 mg·g-1, at 313 K indicates good adsorption for Congo red.
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