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Stochastic optimisation of organic waste-to-resource value chain Полный текст
2021
Robles, Ivan | Durkin, Alex | Guo, Miao
Organic fraction municipal solid waste (OFMSW) has a high potential for energy and value-added product recovery due to its carbon- and nutrient-rich composition; however, traditional value chains have treated OFMSW as an undesired by-product. This study focuses on value chain optimisation to assist the transition to resource recovery value chains. To achieve this, this work combined two stage stochastic mathematical optimisation with geographical spatial analysis and time series waste generation analysis. Existing infrastructure in England, including anaerobic digestion plants and road transportation networks, were included in the model. To account for uncertainty in waste generation, multiple scenarios and their associated probabilities were developed based on environmental variables. The optimisation problem was solved to further advance the understanding of economically optimal waste-to-resource value chains under waste generation variability. The pertinent decision variables included sizing, technology selection, waste flows and location of thermochemical treatment sites. The model highlights the potential reduction in system profitability as a result of different operating constraints, such as minimum plant operating capacity factors and landfill taxation. The latter was shown to have the largest impact on profitability as overconservative systems designs were implemented to hedge against the waste variability. Such computer-aided models offer opportunities to overcome the challenges posed by waste generation variability and waste to resource value chain transformation.
Показать больше [+] Меньше [-]Reduction of CO2 emissions with automatic mooring systems. The case of the port of Santander Полный текст
2017
Ortega Piris, Andrés | Díaz-Ruiz-Navamuel, Emma | Pérez-Labajos, Carlos A. | Oria Chaveli, Jesús
The revolutions in the maritime industry resulting from the implementation of integrated transport systems (bulk) and containerization (regular lines) at first had little effect on traditional mooring systems for ships in port. However, the research into innovation in automated mooring systems with increasingly advanced technologies carried on regardless.The so-called “Automatic Mooring Systems” (AMS), automatic systems that allow vessels to be moored without ropes, are being increasingly implemented in numerous ports in many different countries in the world, particularly in those whose traffic volumes have allowed the threshold of profitability of these infrastructures to be reached. But besides the financial benefits, the implantation of the AMS is having positive effects on the environment by reducing CO2 emissions in many commercial ports.The present work aims to measure for the first time the reduction in the CO2 emissions of merchant vessels as a consequence of the substitution of traditional mooring systems with the new automatic systems, continuing along the lines of previous works in the field of the reduction in CO2 emissions in ports.The estimation is made by applying the EPA and ENTEC “bottom-up” methodologies to the traffic in the port of Santander (Spain) in the year 2014.The implementation of the AMS, when compared to the traditional mooring systems, leads to a reduction in CO2 emissions of 76.78% calculated using the EPA method and 76.63% using the ENTEC method. Hence, the Port Authorities in their long-term planning decisions should promote the introduction of automatic mooring systems wherever the profitability thresholds of traffic allow it, as this will lead to significant environmental benefits by substantially reducing CO2 emissions during the maneuvers of merchant ships in maritime commercial ports.
Показать больше [+] Меньше [-]Effects of seawater pH and temperature on foraging behavior of the Japanese stone crab Charybdis japonica Полный текст
2017
Wu, Fangli | Wang, Ting | Cui, Shuaikang | Xie, Zhe | duPont, Sam | Zeng, Jiangning | Gu, Huaxin | Kong, Hui | Hu, Menghong | Lu, Weiqun | Wang, Youji
We examined prey selection and foraging behaviors of the crab Charybdis japonica exposed to four combinations of pH (7.3 and 8.1) and temperature (18°C and 25°C). The order of prey selection by C. japonica was Potamocorbula laevis, Ruditapes philippinarum, Tegillarca granosa and Mactra veneriformis. Under high pCO2, times for searching, breaking, eating and handling were all significantly longer than those at the normal pCO2, and the prey profitability and predation rate under high pCO2 were significantly lower than normal pCO2. Moreover, temperature significantly influenced the foraging behaviors, but its effects were not as strong as those of pH; times for searching, eating and handling under high temperature were significantly lower than the low temperature, and the prey predation rates under high temperature was significantly higher than low temperature. In conclusion, high pCO2 negatively affected the foraging behavior, but high temperature actively stimulated the foraging behaviors of crabs.
Показать больше [+] Меньше [-]Optimized ratoon rice system to sustain cleaner food production in Jianghan Plain, China: a comprehensive emergy assessment Полный текст
2022
Ding, Zijuan | Hu, Ren | Styles, David | Wang, Xiaolong | Tian, Yingbing | Cao, Yuxian | Hou, Jun
Ratoon rice (RR) is regarded as a labor-saving and efficient approach to rice cultivation; however, sub-optimal production techniques (fertilization, irrigation, harvesting) may lead to serious environmental problems and unsustainable agriculture. In this study, emergy analysis was combined with indicators of soil fertility, global warming potential (GWP), and profitability to comprehensively assess the sustainability performance of three cultivation modes: (i) traditional farm practice (TRA), (ii) optimized mode (OPT), and (iii) OPT plus green manure planting (OPTM). Over 2 years, compared with the TRA mode, OPT and OPTM modes increased total rice yield by 10% and 19% on average and improved profit by 233.7 and 456.5 Yuan ha⁻¹, respectively. Single emergy analysis results showed that, compared with the TRA mode, OPT and OPTM (2-year average value) modes increased production efficiency by 10% and 8%, reduced renewable fraction and emergy sustainability index by 14–19% and 18–23%, respectively, and increased environmental loading ratio by 31% and 22%. Multiple EMA analysis results showed that, compared with the TRA mode, OPT and OPTM (2-year average value) modes reduced UEVNₘᵢₙ by 23% and 21% and increased UEVGWP 32% and 51%, respectively. The UEVTₒₜₐₗ ᵣₑᵥₑₙᵤₑ and UEVBₑₙₑfᵢₜ of OPT and OPTM increased by 8–29% and 4–37%, respectively, compared with TRA mode. The comprehensive assessment indicated that, despite OPT and OPTM modes have a range of improvements and dis-improvements versus the TRA mode, OPTM was the more sustainable mode of RR production overall. However, some sustainability indicators remained poor, and there remains scope for further optimization via, e.g., precision application of enhanced-efficiency fertilizers, application of a straw-decomposing inoculant to improve soil fertility, and use of new improved rice varieties with high regenerative ability to improve the yield of ratoon crops.
Показать больше [+] Меньше [-]Study on the strategy of improving the life cycle economic sustainability of wind power heating projects in northern China Полный текст
2022
Wang, Weijun | Dong, Zeyuan
The profitability of electric heating projects in Northern China is poor. A kind of combined market-oriented trading strategy to improve the economy of electric heating projects is put forward. The price game model for direct power purchase, compensation model for carbon emission reduction benefits and load aggregation revenue model are constructed, and the optimal proportion of clean energy and conventional energy consumed under the condition of ensuring heating reliability is analyzed. An electric heating project was analyzed as an example, the results showed that in the direct power purchase transaction, the power price is 0.2125 RMB/kWh, which is 0.0591 RMB/kWh lower than the catalogue tariff. Revenue from carbon trading and auxiliary service transaction is 469,913.87 RMB and 289,218.09 RMB, respectively, which is equivalent to reducing electricity cost of 0.0253 RMB/kWh and 0.0156 RMB/kWh, respectively. The ultimate power cost is 0.1716RMB/kWh, which is 0.1 RMB/kWh lower than the current catalogue tariff. Besides, the more clean energy an electric heating project consumes, the better its economy will be, and in this example, the best proportion of clean energy and conventional energy is 80% and 20%. The research results could help to promote the sustainable development of clean heating in northern China.
Показать больше [+] Меньше [-]Can the social trust promote corporate green innovation? Evidence from China Полный текст
2021
Pan, Zicheng | Liu, Liang | Bai, Shuyuan | Ma, Qianting
Corporate green innovation has played a crucial role in balancing profitability and environmental protection. The existing research on determinant factors of green innovation has its main defects in emphasizing excessively enterprise’s formal institutional environment and neglecting the informal institutional environment, causing an incomplete understanding of the relationship between institutional environments and corporate green innovation. To bridge this gap, using a sample of Shanghai and Shenzhen A-share listed firms in manufacturing industry during the period of 2010–2016, we investigate how social trust, an important informal institutions, affects corporate green innovation. Our results show that social trust is positively associated with green innovation, remaining valid after applying endogenous and robustness tests. In addition, the positive relationship between social trust and green innovation is more prominent when the enterprise is non-state-owned or locates in a looser command-and-control (CAC) environmental regulations region. Further analysis shows that social trust boosts corporate green innovation via promoting knowledge sharing, decreasing financing constraints, and fulfilling more corporate social responsibility (CSR). This paper enriches the literature concerning social trust and green innovation and draws back more public attention on the role of informal institutions play in promoting green innovation.
Показать больше [+] Меньше [-]Energy, emission, profitability, and sustainability analyses of a grid-connected solar power plant proposed in airport sites of Bangladesh: a case study Полный текст
2021
Chowdhury, Hemal | Chowdhury, Tamal | Hossain, Nazia | Chowdhury, Piyal | dos Santos Mascarenhas, Jefferson | Bhuiya, Muhammad Mostafa Kamal
Nowadays, the aviation industry is one of the significant contributors to greenhouse gas emissions. An optimum solution to this concern is the substitution of conventional electricity consumption with clean energy sources. Barren lands are available in airport sites as buffer zones. These lands can be utilized to generate electricity from clean energy sources like solar, wind, and others. This study proposed a 5 MW grid-connected solar power plant at airport sites by utilizing the substantial barren area of the airport. The targeted airports for this study are Hazrat Shahjalal International Airport, Dhaka, and Shah Amanat International Airport, Chittagong, Bangladesh. Mathematical and simulation analyses have been performed for this purpose. Besides, sustainability analysis has also been incorporated for the grid-connected solar power plant. The energy efficiency varies from 18.74 to 7.79% for the Shah Amanat International Airport, and for the Hazrat Shahjalal International Airport, it ranges from 17.71 to 7.45%. Based on the project outcome, the revenue earned was 25% higher if the total cost was invested in power plants rather than keeping it in the bank as a deposit. On the other hand, emission analysis presented that a gross reduction of 3827.5 tons of CO₂/MWh can be achieved from the Shah Amanat International Airport, while 3926 tons of CO₂/MWh can be removed from the Hazrat Shahjalal International Airport. Based on the sustainability analysis, the energy depletion ratio for Shahjalal Airport varies from 0.82 to 0.93, while for Shah Amanat Airport, it is in the range of 0.81 and 0.92. The findings of this study suggested that investment in grid-connected solar power plants is economically viable and environmentally benign.
Показать больше [+] Меньше [-]Efficacy of feed improvement in livestock farming to offset climate variations in Punjab, Pakistan: silage as an example Полный текст
2021
Raza, Kashif | Wang, Guixia | Naqvi, Syed Asif Ali | ul Hassan, Rai Hasis
Globally, climate change is an alarming threat to the livestock industry. Such changes in the climate can also adversely affect the returns of livestock farmers in Pakistan. Improvement in the production process could decrease the risk of losses. This study analyzes the efficacy of silage to abate the losses in livestock profitability resulting from the climate change. The study employed cross-sectional survey data of 492 livestock farmers collected from six districts of Punjab Province, Pakistan. The data are analyzed with endogenous switching regression, considering the possibility of selection bias and endogeneity in adopting silage as a climate change adaptation measure. The study findings show a significant difference in material well-being between silage users and conventional feed users. Furthermore, training programs such as silage training and livestock development programs could be meaningful provisions to abate climate change and improve food security. It is suggested that training and development programs should be incorporated in policy plans to improve the well-being of farmers in terms of their farm revenues.
Показать больше [+] Меньше [-]The environmental impact of shrimp aquaculture and the coastal pollution in Mexico
1998
Paez-Osuna, F. | Guerrero-Galvan, S.R. | Ruiz-Fernandez, A.C. (Estacion Mazatlan, Instituto de Ciencias del Mar y Limnologia, Universidad Nacional Autonoma de Mexico, Apdo. Postal 811, Mazatlan 82000, Sinaloa (Mexico))
Economic benefits of construction waste recycling enterprises under tax incentive policies Полный текст
2022
Liu, Jingkuang | Gong, Engqing | Wang, Xuetong
To further explore the development of construction waste recycling enterprises and promote the recycling of construction waste resources in China, a system dynamics model of the economic benefits of construction waste recycling enterprises is established using the system dynamics method and taking the tax incentive of the Guangzhou Municipal Government as an example. The economic benefits of construction waste recycling enterprises are analyzed from the perspective of the total cost, total revenue, and total recycling amount. The results of the MATLAB simulation and numerical analysis show that (1) by simulating the effects of different taxes such as value-added tax (VAT), education surcharge, urban construction tax, and enterprise income tax on the economic benefits of construction waste recycling enterprises, it is found that when tax incentives reach 70%, the VAT favorable policies bring the highest gains, followed by enterprise income tax, whereas favorable education surcharge policies and urban construction tax have the least impact on economic benefits. (2) Taking the monetary subsidy of the Guangzhou municipal government as an example, it is estimated that the total revenue of construction waste recycling enterprises will increase by 33.56% annually in 2030. When the new production technology is adopted, the return on investment (ROI) will reach 46.8% in 2030 compared to previous technological improvements. In the simulation scenario, the ROI will be 42.2%, which has a good incentive effect on the cost control of enterprises. (3) Increasing the available power to VAT and corporate income tax can improve the profitability of construction waste recycling enterprises in China; however, tax incentive policy will no longer be the main factor affecting the benefits of enterprises when a certain time is reached. (4) It is suggested that the government improves the relevant tax laws incentive policies, increase tax incentives, and add equipment tax incentive policies, actively change the tax mode, and increase indirect tax models to improve the economic benefits of enterprises. The research results provide a decision-making reference for the government to formulate laws and policies related to the economic benefits of construction waste recycling and promote the development of the construction waste recycling industry, the development of new industries, such as waste recycling and treatment, and the formation of industrial chains, to achieve the strategic goal of sustainable development.
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