[Objective]Study on carbon sink effects in Conversion of Farmland to Forest Project in Hongfenghu drainage basin in order to provide evidences for assessing carbon sink potential of conversion of farmland to forest in...[Objective]Study on carbon sink effects in Conversion of Farmland to Forest Project in Hongfenghu drainage basin in order to provide evidences for assessing carbon sink potential of conversion of farmland to forest in Guizhou Province.[Method]By investigating the implement of Conversion of Farmland to Forest Project in Hongfenghu drainage basin from 2000 to 2006,the carbon sink amount and effect of seven main tree species in the foreat region like Cunninghamia lanceolata,Cryptomeria fortunei,Amygdalus persica,Prunus salicina,Armeniaca vulgaris,Camptotheca acuminate and Catalpa bungei were calculated,based on which the amount of forest carbon sinks in Hongfenghu drainage basin in 2015 was estimated.[Result]Biomass storage and carbon sink amount in middle and young aged forests were increasing over time from 2000 to 2006,which reached 1.05×107 kg by 2006 and would engage more and more potential.Cunninghamia lanceolata has the superior carbon sink capacity in the seven tree species in the research region,of which the amount of carbon sink per unit area will be 106.51 t/hm2 by 2015,followed by Cryptomeria fortunei with the amount of carbon sink per unit area by 99.42 t/hm2.Armeniaca vulgaris has the weakest carbon sink capacity of all the seven species with the amount of 13.03 t/hm2.The total amount of carbon sink in seven tree species was 2.35×107 kg,while the average amount of carbon sink per unit area was 26.17 t/hm2,which could produced economic benefit of 7.17×106 yuan calculated on the price of 305.0 yuan/t or 5.91×106 yuan calculated on the price of 254.1 yuan/t.[Conclusion]Economic benefits of carbon sink effects of Conversion of Farmland to Forest Project in Hongfenghu drainage basin were great with huge appreciation potential.展开更多
Least squares support vector machines (LS-SVMs), a nonlinear kemel based machine was introduced to investigate the prospects of application of this approach in modelling water vapor and carbon dioxide fluxes above a s...Least squares support vector machines (LS-SVMs), a nonlinear kemel based machine was introduced to investigate the prospects of application of this approach in modelling water vapor and carbon dioxide fluxes above a summer maize field using the dataset obtained in the North China Plain with eddy covariance technique. The performances of the LS-SVMs were compared to the corresponding models obtained with radial basis function (RBF) neural networks. The results indicated the trained LS-SVMs with a radial basis function kernel had satisfactory performance in modelling surface fluxes; its excellent approximation and generalization property shed new light on the study on complex processes in ecosystem.展开更多
Nowadays, by the increasing attention to environment and high rate of fuel production, recycling of purge gas as reactant to a reactor is highly considered. In this study, it is proposed that the purge gases of methan...Nowadays, by the increasing attention to environment and high rate of fuel production, recycling of purge gas as reactant to a reactor is highly considered. In this study, it is proposed that the purge gases of methanol production unit, which are approximately15.018 t·h^(-1) in the largest methanol production complexes in the world, can be recycled to the reactor and utilized for increasing the production rate. Purge gas streams contain 63% hydrogen,20% carbon monoxide and carbon dioxide as reactants and 17% nitrogen and methane as inert. The recycling effect of beneficial components on methanol production rate has been investigated in this study. Simulation results show that methanol production enhances by recycling just hydrogen, carbon dioxide and carbon monoxide which is an effective configuration among the others. It is named as Desired Recycle Configuration(DRC) in this study. The optimum fraction of returning purge gas is calculated via one dimensional modeling of process and Response Surface Methodology(RSM) is applied to maximize the methanol flow rate and minimize the carbon dioxide flow rate. Simulation results illustrate that methanol flow rate increases by 0.106% in DRC compared to Conventional Recycle Configuration(CRC) which therefore shows the superiority of applying DRC to CRC.展开更多
Soil Organic Carbon (SOC) is the most important component of soil. Though small, it determines soil fertility and prevents soil losses. In this study, we examined relationships between the Particle-Size Distribution...Soil Organic Carbon (SOC) is the most important component of soil. Though small, it determines soil fertility and prevents soil losses. In this study, we examined relationships between the Particle-Size Distribution (PSD) of the eroded sediment and SOC loss, and evaluated the effects of plant coverage ratios (0%, 15%, 30%, 45%, 60% and 90%), slope lengths (2 m, 4 m), fertilizer treatments (unfertilized control (CK), compound N-P-K fertilizer (CF), and organic fertilizer (OF)) on SOC loss and the SOC enrichment ratio (ERsoc) in the eroded sediments. The experimental results showed that longer slope length and lower surface cover ratios produced larger surface runoff and the eroded sediments, resulting in larger SOC losses. The average SOC loss was greatest in the OF treatment and SOC loss was mainly associated with the eroded sediment. Surface runoff, which causes soil erosion, is a selective transportation process, hence there were more clay- sized particles (〈2 μm) and silt-sized particles (2-50μm) in the eroded sediments than in the original soils. SOC was enriched in the eroded sediments relative to in the original soil when ERsoc 〉 1. ERsoc was positively correlated with ERclay (〈2 pro) (R^2 = o.68) and ERie at (2-20 μm) (R2 = 0.63), and from all the size particle categories of the original soil or the eroded sediments, more than 95% of SOC was concentrated in small-sized partieles (〈50 μm). The distribution of SOC in different-sized particles of the original soil and the eroded sediment is primarily associated with clay-sized part-ides and fine silt-sized particles, thus we eonelude that as the eroded sediment partieles became finer, more SOC was absorbed, resulting in more severe SOC loss.展开更多
As a preliminary investigation towards obtaining carbon nanotube composite adsorbent for CO2 capture, in this study CO2 adsorption performance of three commercial carbon nanotubes (CNTs) one single-walled carbon nan...As a preliminary investigation towards obtaining carbon nanotube composite adsorbent for CO2 capture, in this study CO2 adsorption performance of three commercial carbon nanotubes (CNTs) one single-walled carbon nanotubes (SWCNTs), and two (2) different multi-walled carbon nanotubes (referred to as A-MWCNTs and B-MWCNTs) were evaluated and compared. The purpose of this study was to compare the different types of CNTs and select the best to serve as the solid anchor in the development of a hydrophobic composite adsorbent material for CO2 capture. The N2 physi- sorption of the CNTs was conducted to determine their surface area, pore volume and pore size. In addition, morphology and purity of the CNTs were checked with Transmission Electron Microscopy and Raman Spectroscopy, respectively. The CO2 adsorption capacity of the CNTs was evaluated using Thermo-gravimetric analysis (TGA) at 1.1 bar, at operating temperature ranged from 25 to 55 ~C and at different CO2 feed flow rates, in order to evaluate the effects of these variables on the CO2 adsorption capacity. The results of CO2 adsorption with the TGA show that CO2 adsorption capacity for both SWCNTs and MWCNTs was the highest at 25 ~C. Changing the CO2 flowrates had no significant effect on the adsorption capacity of MWCNTs, but decreasing the CO2 flow rate resulted in the enhancement of the CO2 adsorption capacity of SWCNTs. Overall, it was found that the SWCNTs displayed the highest CO2 adsorption capacity (29.97 gCO2/kg ad- sorbent) when compared to the MWCNTs (12.09 gCO2/kg adsorbent), indicating a 150% increase in adsorption capacity over MWCNTs.展开更多
Dimethyl carbonate is an environmentally benign and biodegradable chemical.Based on integration of reactive distillation and pressure-swing distillation technologies,a novel process for synthesis of dimethyl carbonate...Dimethyl carbonate is an environmentally benign and biodegradable chemical.Based on integration of reactive distillation and pressure-swing distillation technologies,a novel process for synthesis of dimethyl carbonate through transesterification with propylene carbonate and methanol has been developed by Huang et al.In this work,the optimization of this process was performed by minimizing the total TAC.The results show that the optimal design flowsheet can save energy consumption by 18.6% with the propylene carbonate conversion of 99.9%.Then,an effective plant-wide control structure for the process was developed.Dynamic simulation results demonstrate that the temperature/flow rate cascade control plus with simple temperature control can keep not only product purity but also the conversion of the reactant at their desired values in the face of the disturbance in reactant feed flow rate and feed composition.展开更多
Experimentally, the electron drag effect on carbon nanotube surface in flowing liquids was investigated. It was found that electric current could be generated in metallic carbon nanotubes immersed in the liquids. Carb...Experimentally, the electron drag effect on carbon nanotube surface in flowing liquids was investigated. It was found that electric current could be generated in metallic carbon nanotubes immersed in the liquids. Carbon nanotubes were synthesized on Si substrate by hot filament chemical vapor deposition. The experimental results showed that the flow-induced current on the surface of carbon nanotube films was closely depended on the flow rate, concentration, properties and temperature of liquids. The flow-induced current was increased with the increasing of flow rate, concentration and temperature of liquids. The obtained results were discussed in detail.展开更多
In November 2011, the Australian government approved the legislation (Clean Energy Act 2011) to introduce a reduction plan of carbon emissions in Australia. This plan will be implemented from July 2012. This is one ...In November 2011, the Australian government approved the legislation (Clean Energy Act 2011) to introduce a reduction plan of carbon emissions in Australia. This plan will be implemented from July 2012. This is one of the first accounting studies to investigate the potential impacts of this plan on long-lived asset values and operating cash flows for Australian listed companies. A sample of Australian Securities Exchange (ASX) 200 indexed companies from 2'006 to 2010 is used. Hypotheses are tested based on Heckman's (1979) two-stage approach. Three regression models are developed to examine the association between carbon emissions and asset values/operating cash flows. This study finds that asset values and operating cash flows will be adversely affected, if the reduction plan is implemented. Specifically, this study finds that the book value of long-lived assets will decrease, if listed companies are considered to be emissions-liable. The book value of long-lived assets is further found to be negatively associated with listed companies' carbon emission levels. This study also demonstrates that operating cash flows of emissions-liable companies will be adversely affected. However, this study does not find a relationship between operating cash flows and companies' emission levels. The empirical findings from Australian listed companies provide the evidence that the reduction plan of carbon emissions will adversely affect corporate entities' asset values and operating cash flows. The results further indicate that the magnitude of the impact will be proportional to the companies' emission levels. The implications of these empirical findings for listed companies, for the accounting profession, and for carbon emission regulators are also discussed.展开更多
Like in other sectors of activity, the sustainability in refrigeration systems is a mandatory goal to achieve, namely at house holdings, bars and restaurants, where small-scale refrigerators and freezers are widely us...Like in other sectors of activity, the sustainability in refrigeration systems is a mandatory goal to achieve, namely at house holdings, bars and restaurants, where small-scale refrigerators and freezers are widely used. The aim of this work is to demonstrate experimentally, trough measurements carried out in these equipments, the improvement that can be achieved if several modifications are implemented in traditional household refrigeration systems. In addition, it was also simulated and analysed experimentally a slightly different equipment, a refrigeration system used for draught beverages. Both systems work on a single vapour compression refrigeration with R-134a as working fluid. In the end, by implemented the modifications tested in the virtual model, it was possible to improve their thermal behaviour, a decrease in electrical energy consumption, as well as, the associated CO2 emissions reduction can be attained. In this project, the CFD (Computational Fluid Dynamics) soffware--ANSYS Fluent was used to simulate the ambient temperature and velocity fields inside the refrigerator and in that way to validate the measured results.展开更多
With CO combustion promoters, the role of combustion air flow rate for concerns of economics and control is important. The combustion air is conceptually divided to three parts: the air consumed by coke burning,the ai...With CO combustion promoters, the role of combustion air flow rate for concerns of economics and control is important. The combustion air is conceptually divided to three parts: the air consumed by coke burning,the air consumed by CO combustion and the air unreacted. A mathematical model of a fluid catalytic cracking(FCC)unit, which includes a quantitative correlation of CO heterogeneous combustion and the amount of CO combustion promoters, is introduced to investigate the effects of promoters on the three parts of combustion air. The results show that the air consumed by coke burning is almost linear to combustion air flow rate, while the air consumed by CO combustion promoters tends to saturate as combustion air flow rate increases, indicating that higher air flow rate can only be used as a manipulated variable to control the oxygen content for an economic concern.展开更多
基金Supported by The High-level Personnel Special Assistance Genome Project of Guizhou Province(TJZF(2009)25)Science and Technology Fund of Guizhou Province((2009)2251)The Key Projectof Chinese Ministry of Education.(210201)~~
文摘[Objective]Study on carbon sink effects in Conversion of Farmland to Forest Project in Hongfenghu drainage basin in order to provide evidences for assessing carbon sink potential of conversion of farmland to forest in Guizhou Province.[Method]By investigating the implement of Conversion of Farmland to Forest Project in Hongfenghu drainage basin from 2000 to 2006,the carbon sink amount and effect of seven main tree species in the foreat region like Cunninghamia lanceolata,Cryptomeria fortunei,Amygdalus persica,Prunus salicina,Armeniaca vulgaris,Camptotheca acuminate and Catalpa bungei were calculated,based on which the amount of forest carbon sinks in Hongfenghu drainage basin in 2015 was estimated.[Result]Biomass storage and carbon sink amount in middle and young aged forests were increasing over time from 2000 to 2006,which reached 1.05×107 kg by 2006 and would engage more and more potential.Cunninghamia lanceolata has the superior carbon sink capacity in the seven tree species in the research region,of which the amount of carbon sink per unit area will be 106.51 t/hm2 by 2015,followed by Cryptomeria fortunei with the amount of carbon sink per unit area by 99.42 t/hm2.Armeniaca vulgaris has the weakest carbon sink capacity of all the seven species with the amount of 13.03 t/hm2.The total amount of carbon sink in seven tree species was 2.35×107 kg,while the average amount of carbon sink per unit area was 26.17 t/hm2,which could produced economic benefit of 7.17×106 yuan calculated on the price of 305.0 yuan/t or 5.91×106 yuan calculated on the price of 254.1 yuan/t.[Conclusion]Economic benefits of carbon sink effects of Conversion of Farmland to Forest Project in Hongfenghu drainage basin were great with huge appreciation potential.
基金Project supported by the National Science Fund for OutstandingYouth Overseas (No. 40328001) and the Key Research Plan of theKnowledge Innovation Project of the Institute of Geographic Sciencesand Natural Resources, Chinese Academy of Sciences (No.KZCXI-SW-01)
文摘Least squares support vector machines (LS-SVMs), a nonlinear kemel based machine was introduced to investigate the prospects of application of this approach in modelling water vapor and carbon dioxide fluxes above a summer maize field using the dataset obtained in the North China Plain with eddy covariance technique. The performances of the LS-SVMs were compared to the corresponding models obtained with radial basis function (RBF) neural networks. The results indicated the trained LS-SVMs with a radial basis function kernel had satisfactory performance in modelling surface fluxes; its excellent approximation and generalization property shed new light on the study on complex processes in ecosystem.
文摘Nowadays, by the increasing attention to environment and high rate of fuel production, recycling of purge gas as reactant to a reactor is highly considered. In this study, it is proposed that the purge gases of methanol production unit, which are approximately15.018 t·h^(-1) in the largest methanol production complexes in the world, can be recycled to the reactor and utilized for increasing the production rate. Purge gas streams contain 63% hydrogen,20% carbon monoxide and carbon dioxide as reactants and 17% nitrogen and methane as inert. The recycling effect of beneficial components on methanol production rate has been investigated in this study. Simulation results show that methanol production enhances by recycling just hydrogen, carbon dioxide and carbon monoxide which is an effective configuration among the others. It is named as Desired Recycle Configuration(DRC) in this study. The optimum fraction of returning purge gas is calculated via one dimensional modeling of process and Response Surface Methodology(RSM) is applied to maximize the methanol flow rate and minimize the carbon dioxide flow rate. Simulation results illustrate that methanol flow rate increases by 0.106% in DRC compared to Conventional Recycle Configuration(CRC) which therefore shows the superiority of applying DRC to CRC.
基金funded by Water and Soil Conservation Monitoring Technology Innovation Team and Construction of China(Grant No.2009F20022)National Natural Science Foundation of China(Grant No.41471221)
文摘Soil Organic Carbon (SOC) is the most important component of soil. Though small, it determines soil fertility and prevents soil losses. In this study, we examined relationships between the Particle-Size Distribution (PSD) of the eroded sediment and SOC loss, and evaluated the effects of plant coverage ratios (0%, 15%, 30%, 45%, 60% and 90%), slope lengths (2 m, 4 m), fertilizer treatments (unfertilized control (CK), compound N-P-K fertilizer (CF), and organic fertilizer (OF)) on SOC loss and the SOC enrichment ratio (ERsoc) in the eroded sediments. The experimental results showed that longer slope length and lower surface cover ratios produced larger surface runoff and the eroded sediments, resulting in larger SOC losses. The average SOC loss was greatest in the OF treatment and SOC loss was mainly associated with the eroded sediment. Surface runoff, which causes soil erosion, is a selective transportation process, hence there were more clay- sized particles (〈2 μm) and silt-sized particles (2-50μm) in the eroded sediments than in the original soils. SOC was enriched in the eroded sediments relative to in the original soil when ERsoc 〉 1. ERsoc was positively correlated with ERclay (〈2 pro) (R^2 = o.68) and ERie at (2-20 μm) (R2 = 0.63), and from all the size particle categories of the original soil or the eroded sediments, more than 95% of SOC was concentrated in small-sized partieles (〈50 μm). The distribution of SOC in different-sized particles of the original soil and the eroded sediment is primarily associated with clay-sized part-ides and fine silt-sized particles, thus we eonelude that as the eroded sediment partieles became finer, more SOC was absorbed, resulting in more severe SOC loss.
文摘As a preliminary investigation towards obtaining carbon nanotube composite adsorbent for CO2 capture, in this study CO2 adsorption performance of three commercial carbon nanotubes (CNTs) one single-walled carbon nanotubes (SWCNTs), and two (2) different multi-walled carbon nanotubes (referred to as A-MWCNTs and B-MWCNTs) were evaluated and compared. The purpose of this study was to compare the different types of CNTs and select the best to serve as the solid anchor in the development of a hydrophobic composite adsorbent material for CO2 capture. The N2 physi- sorption of the CNTs was conducted to determine their surface area, pore volume and pore size. In addition, morphology and purity of the CNTs were checked with Transmission Electron Microscopy and Raman Spectroscopy, respectively. The CO2 adsorption capacity of the CNTs was evaluated using Thermo-gravimetric analysis (TGA) at 1.1 bar, at operating temperature ranged from 25 to 55 ~C and at different CO2 feed flow rates, in order to evaluate the effects of these variables on the CO2 adsorption capacity. The results of CO2 adsorption with the TGA show that CO2 adsorption capacity for both SWCNTs and MWCNTs was the highest at 25 ~C. Changing the CO2 flowrates had no significant effect on the adsorption capacity of MWCNTs, but decreasing the CO2 flow rate resulted in the enhancement of the CO2 adsorption capacity of SWCNTs. Overall, it was found that the SWCNTs displayed the highest CO2 adsorption capacity (29.97 gCO2/kg ad- sorbent) when compared to the MWCNTs (12.09 gCO2/kg adsorbent), indicating a 150% increase in adsorption capacity over MWCNTs.
基金Supported by the National Natural Science Foundation of China(21306025,21576053)the International Science&Technology Cooperation Program of China(2013DFR90540)
文摘Dimethyl carbonate is an environmentally benign and biodegradable chemical.Based on integration of reactive distillation and pressure-swing distillation technologies,a novel process for synthesis of dimethyl carbonate through transesterification with propylene carbonate and methanol has been developed by Huang et al.In this work,the optimization of this process was performed by minimizing the total TAC.The results show that the optimal design flowsheet can save energy consumption by 18.6% with the propylene carbonate conversion of 99.9%.Then,an effective plant-wide control structure for the process was developed.Dynamic simulation results demonstrate that the temperature/flow rate cascade control plus with simple temperature control can keep not only product purity but also the conversion of the reactant at their desired values in the face of the disturbance in reactant feed flow rate and feed composition.
文摘Experimentally, the electron drag effect on carbon nanotube surface in flowing liquids was investigated. It was found that electric current could be generated in metallic carbon nanotubes immersed in the liquids. Carbon nanotubes were synthesized on Si substrate by hot filament chemical vapor deposition. The experimental results showed that the flow-induced current on the surface of carbon nanotube films was closely depended on the flow rate, concentration, properties and temperature of liquids. The flow-induced current was increased with the increasing of flow rate, concentration and temperature of liquids. The obtained results were discussed in detail.
文摘In November 2011, the Australian government approved the legislation (Clean Energy Act 2011) to introduce a reduction plan of carbon emissions in Australia. This plan will be implemented from July 2012. This is one of the first accounting studies to investigate the potential impacts of this plan on long-lived asset values and operating cash flows for Australian listed companies. A sample of Australian Securities Exchange (ASX) 200 indexed companies from 2'006 to 2010 is used. Hypotheses are tested based on Heckman's (1979) two-stage approach. Three regression models are developed to examine the association between carbon emissions and asset values/operating cash flows. This study finds that asset values and operating cash flows will be adversely affected, if the reduction plan is implemented. Specifically, this study finds that the book value of long-lived assets will decrease, if listed companies are considered to be emissions-liable. The book value of long-lived assets is further found to be negatively associated with listed companies' carbon emission levels. This study also demonstrates that operating cash flows of emissions-liable companies will be adversely affected. However, this study does not find a relationship between operating cash flows and companies' emission levels. The empirical findings from Australian listed companies provide the evidence that the reduction plan of carbon emissions will adversely affect corporate entities' asset values and operating cash flows. The results further indicate that the magnitude of the impact will be proportional to the companies' emission levels. The implications of these empirical findings for listed companies, for the accounting profession, and for carbon emission regulators are also discussed.
文摘Like in other sectors of activity, the sustainability in refrigeration systems is a mandatory goal to achieve, namely at house holdings, bars and restaurants, where small-scale refrigerators and freezers are widely used. The aim of this work is to demonstrate experimentally, trough measurements carried out in these equipments, the improvement that can be achieved if several modifications are implemented in traditional household refrigeration systems. In addition, it was also simulated and analysed experimentally a slightly different equipment, a refrigeration system used for draught beverages. Both systems work on a single vapour compression refrigeration with R-134a as working fluid. In the end, by implemented the modifications tested in the virtual model, it was possible to improve their thermal behaviour, a decrease in electrical energy consumption, as well as, the associated CO2 emissions reduction can be attained. In this project, the CFD (Computational Fluid Dynamics) soffware--ANSYS Fluent was used to simulate the ambient temperature and velocity fields inside the refrigerator and in that way to validate the measured results.
基金Supported by the National Natural Science Foundation of China(21006127)the National Basic Research Program of China(2012CB720500)
文摘With CO combustion promoters, the role of combustion air flow rate for concerns of economics and control is important. The combustion air is conceptually divided to three parts: the air consumed by coke burning,the air consumed by CO combustion and the air unreacted. A mathematical model of a fluid catalytic cracking(FCC)unit, which includes a quantitative correlation of CO heterogeneous combustion and the amount of CO combustion promoters, is introduced to investigate the effects of promoters on the three parts of combustion air. The results show that the air consumed by coke burning is almost linear to combustion air flow rate, while the air consumed by CO combustion promoters tends to saturate as combustion air flow rate increases, indicating that higher air flow rate can only be used as a manipulated variable to control the oxygen content for an economic concern.