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Energy crisis and environmental pollution have become major challenges in China’s economic development, which has triggered the demand for alternative energy sources and promoted the popularization of ground source heat pump technology. A ground source heat pump (GSHP) is a central heating and/or cooling system that transfers heat to or from the ground. It uses the earth as a heat source (in the winter) or a heat sink (in the summer). This design takes advantage of the moderate temperatures in the ground to boost efficiency and reduce the operational costs of heating and cooling systems. This paper adopted the STIRPAT model and the influencing factors were analyzed. The major influencing factors were population (P), urbanization level (U), GDP per capita (A), energy consumption per capita (E), industrial structure (IS), R&D (T), central heating area (HA), and policy investment (PI). However, these factors themselves had strong collinearity, which might produce some uncertain impacts on the final results. To avoid the impact of collinearity, the method of partial least squares (PLS) was used. The results showed that P, U, A, E, T, HA, and PI had positive effects on GSHP, while IS had a slight effect on GSHP. This paper found that A is the most dominant factor and the effect of the IS could almost be ignored. Some policy recommendations were given on how to promote the application of GSHP systems and mitigate the growth of CO₂ emissions.
China is facing increasing pressure on international emissions. As the capital of China, Beijing should set an example for carbon emissions. Previous studies on carbon emissions mainly focused on household size and changes in household consumption structure during urbanization. The input-output method is mainly used, but the total output of each department is used to measure the intensity of CO₂ emissions, so that the middle input and added value among the sectors are included, which leads to a large measurement result. Based on the input-output model, the paper chooses the latest input-output table of Beijing in 2012 and calculates the carbon emissions of residents in Beijing in 2012, which calculates the CO₂ emission intensity by using the added value that avoids the problem of double counting. The results show that the total carbon emissions of Beijing residents is 762.948 million tons, of which the direct consumption energy of urban residents is mainly gasoline and heat, while that of rural residents is mainly coal and electricity. Indirect carbon emissions of residential consumption are divided into eight consumption categories. Among them, 57.2% and 18.9% were in transportation and housing, respectively. According to the above conclusions, this paper makes some recommendations.
Balancing sustained economic growth with energy security and environmental and climate change constraints is a common but difficult challenge. China, as the largest energy consumer in the world – 90% of which is fossil fuel-based – faces the enormous task of transforming its energy mix to low-emissions. CO₂ has been successfully injected for the purposes of both carbon capture and storage (CCS) and enhanced oil recovery (EOR). This study employs life cycle assessment to quantify the CO₂ emissions from the CCS-EOR system to analyze net CO₂ emissions. This system includes carbon capture, transportation, EOR, downstream, and consumption. Our model analyzes life cycle CO₂ emissions from plants of integrated gasification combined cycle (IGCC) with CCS, pulverized coal plants (PC) with CCS, and oxy-fuel plants with CCS while we use technologies of fractionation, refrigeration, Ryan-Holmes, and membrance in the process of EOR. Total CO₂ emissions are 114.69-121.50 Mt CO₂e, 222.95-236.19 Mt CO₂e, and 49.09-51.96 Mt CO₂e from IGCC, PC, and oxy-fuel plants, respectively, based on IGCC with 426 MW, PC with 600 MW, and oxy-fuel with 200 MW in China. Emissions from the combustion of refined petroleum fuel is the most of total emissions – from 66.21% to 71.35%, emissions from EOR are 14.27-19.32%, emissions from downstream are 8.47-9.13%, emissions from capture are 4.12-5.09%, and emissions from transportation are 0.47-1.61%. Based on these results, CCS-EOR (where CO₂ is sourced from IGCC, PC and oxy-fuel plants) provides one potential means for producing electricity and oil to meet growing energy demand and reducing CO₂ emissions to abate global warming.
In this study we used the cuttings of Populus przewalskii Maximowicz as experimental material and sodium nitroprusside (SNP) as nitric oxide (NO) donor to determine the physiological and biochemical responses to drought stress and the effect of NO on drought tolerance in woody plants. The results indicated that drought stress not only significantly decreased biomass production, but also significantly increased hydrogen peroxide content and caused oxidative stress to lipids and proteins assessed by the increase in malondialdehyde and total carbonyl contents, respectively. The cuttings of P. przewalskii accumulated many amino acids for osmotic adjustment to lower water potential, and activated the antioxidant enzymes such as superoxide dismutase, guaiacol peroxidase and ascorbate peroxidase to maintain the balance of generation and quenching of reactive oxygen species. Moreover, exogenous SNP application significantly heightened the growth performance of P. przewalskii cuttings under drought treatment by promotion of proline accumulation and activation of antioxidant enzyme activities, while under well-watered treatment the effect of SNP application was very little.
The level of cultivated land fertility (CLF) determines food production and quality directly. Therefore, research on evaluating CLF has always been a focus of attention in Chinese academia. Aiming at shortcomings of methods for evaluating CLF presently, this paper proposes an integrated method to evaluate and grade the CLF-adopted GIS, Delphi, analytic hierarchy process (AHP), fuzzy mathematics and comprehensive index model. Furthermore, based on data of the survey project of CLF in Huaping, this paper carried out an empirical study using this method. The result demonstrates that the methods are more scientific and reliable. This is reflected in the following aspects: First, the process of evaluation and grading of CLF is combined with qualitative analysis and quantitative analysis, which make the results more close to the objective reality. Second, the results of the evaluation and grading not only achieved a match between quantitative expression and spatial visualization, but also demonstrated the differences of CLF in quantity and space. Through this study, we hope that this method can further enrich the theory and technology of CLF evaluation to some extent, and also provide a good reference for similar study in other regions.
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There has been an increasing interest in understanding the differential effects of sexual dimorphism on plant stress responses. However, there is no clear pattern in the responses of the sexes to defoliation. In this study, the effects of different severity of artificial defoliation on biomass production, total nonstructural carbohydrate (NSC) concentration, and photosynthetic rate (PN) of male and female Populus deltoides were examined. We used half and full defoliation to observe the differences between the sexes in three harvest dates (1 week, 4 weeks, and 8 weeks after treatments). We hypothesized that female and male P. deltoides compared with an undefoliated control would have compensatory growth in response to defoliation treatments. Results showed that half and full defoliation reduced the growth of both sexes. Following half defoliation, root growth was reduced, especially in males, at T2 (4 weeks after defoliation) and T3 (8 weeks after defoliation), while males showed an increase in height increment under the half defoliation compared with the nondefoliation treatments. By contrast, females were more negatively affected by defoliation than males in terms of biomass after 8 weeks. One week after defoliation, PN increased significantly in females and males under half defoliation (+30%, +32%, respectively) and full defoliation (+58%, +56%, respectively). However, 8 weeks after defoliation, there was little difference in PN between defoliated and undefoliated female cuttings. Increases in stomatal conductance (gs) and leaf nitrogen were observed under fully defoliated female and male cuttings. Moreover, males had less NSC concentrations following half defoliation compared with females. Our results indicate that leaf compensatory growth in male cuttings of P. deltoides was maintained by obtaining greater photosynthetic capacity, higher leaf nitrogen, and lower NSC concentration following half and full defoliation. Our results highlight that females suffered from greater negative effects than did males following half defoliation, but under full defoliation, the differences between both sexes were subtle.
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