A novel bionic swarm intelligence algorithm, called ant colony algorithm based on a blackboard mechanism, is proposed to solve the autonomy and dynamic deployment of mobiles sensor networks effectively. A blackboard m...A novel bionic swarm intelligence algorithm, called ant colony algorithm based on a blackboard mechanism, is proposed to solve the autonomy and dynamic deployment of mobiles sensor networks effectively. A blackboard mechanism is introduced into the system for making pheromone and completing the algorithm. Every node, which can be looked as an ant, makes one information zone in its memory for communicating with other nodes and leaves pheromone, which is created by ant itself in naalre. Then ant colony theory is used to find the optimization scheme for path planning and deployment of mobile Wireless Sensor Network (WSN). We test the algorithm in a dynamic and unconfigurable environment. The results indicate that the algorithm can reduce the power consumption by 13% averagely, enhance the efficiency of path planning and deployment of mobile WSN by 15% averagely.展开更多
The Hot Dry Rock(HDR)is considered as a clean and renewable energy,poised to significantly contribute to the global energy decarbonization agenda.Many HDR projects worldwide have accumulated valuable experience in eff...The Hot Dry Rock(HDR)is considered as a clean and renewable energy,poised to significantly contribute to the global energy decarbonization agenda.Many HDR projects worldwide have accumulated valuable experience in efficient drilling and completion,reservoir construction,and fracture simulation.In 2019,China Geological Survey(CGS)initiated a demonstration project of HDR exploration and production in the Gonghe Basin,aiming to overcome the setbacks faced by HDR projects.Over the ensuing four years,the Gonghe HDR project achieved the first power generation in 2021,followed by the second power generation test in 2022.After establishing the primary well group in the initial phase,two directional wells and one branch well were drilled.Noteworthy progress was made in successfully constructing the targeted reservoir,realizing inter-well connectivity,power generation and grid connection,implementing of the real-time micro-seismic monitoring.A closed-loop technical validation of the HDR exploration and production was completed.However,many technical challenges remain in the process of HDR industrialization,such as reservoir fracture network characterization,efficient drilling and completion,multiple fracturing treatment,continuous injection and production,as well as mitigation of induced seismicity and numerical simulation technology.展开更多
Concrete structures in main coal cleaning plants have been rebuilt and reinforced in the coal mines of the Shanghai Datun Energy Sources Co. Ltd., the first colliery of the Pingdingshan Coal Co. Ltd. and the Sanhejian...Concrete structures in main coal cleaning plants have been rebuilt and reinforced in the coal mines of the Shanghai Datun Energy Sources Co. Ltd., the first colliery of the Pingdingshan Coal Co. Ltd. and the Sanhejian mine of the Xuzhou Mining Group Co. Ltd. In these projects, the operating environment and reliability of concrete structures in the main plants of the three companies were investigated and the safety of the structures inspected. Qualitative and quantitative analyses were made on the special natural, technological and mechanical environments around the structures. On the basis of these analyses, we discuss the long-term, combined actions of the harsh natural (corrosive gases, liquids and solids) and mechanical environments on concrete structures and further investigated the damage and deteriorating mechanisms and curing techniques of concrete structures in the main coal cleaning plants. Our study can provide a theoretical basis for ensuring the reliability of concrete structures in main coal cleaning plants.展开更多
This paper summarizes the results of the implementation of the CDM in Argentina during the first period of commitment of the Kyoto Protocol. From a total of sixty- five projects ideas, forty-four achieved registration...This paper summarizes the results of the implementation of the CDM in Argentina during the first period of commitment of the Kyoto Protocol. From a total of sixty- five projects ideas, forty-four achieved registration under the CDM EB while the rest remained approved at national level (12), under evaluation (2), suspended (5) or rejected (2). Most of the projects focused on the generation of electricity from renewable energy, mainly wind energy and the use of landfill gas and methane for energy. Emissions reductions achieved 33.4% of the expected CERs up to 2012 with strong differences among sectors. Results demonstrated that under the current Argentina’s energy policy framework, the income by the selling of CERs covered less than 6% of the incremental costs for renewable energy projects. A sensitivity analysis to evaluate the impact of CDM in the coverage of incremental costs for renewable energy based on the prices of both the energy in the local market and the CER demonstrated that the best conditions would only cover 15% of those costs. The contribution of CDM to technology transfer in Argentina was minor considering that 45% of the projects qualified as type III where technological learning and capacity building were limited at the level of operation and maintenance of a foreign technology. Domestic and external barriers that prevented a better performance of CDM projects in terms of GHG mitigation, technology transfer and the contribution to a sustainable development were also analyzed.展开更多
The increase of atmospheric carbon dioxide and the global warming due to its greenhouse effect resulted in worldwide concerns. On the other hand, carbon dioxide might be considered as a valuable and renewable carbon s...The increase of atmospheric carbon dioxide and the global warming due to its greenhouse effect resulted in worldwide concerns. On the other hand, carbon dioxide might be considered as a valuable and renewable carbon source. One approach to reduce carbon dioxide emissions could be its capture and recycle via transformation into chemicals using the technologies in C1 chemistry. Despite its great interest, there are difficulties in CO2 separation on the one hand, and thermodynamic stability of carbon dioxide molecule rendering its chemical activity low on the other hand. Carbon dioxide has been already used in petrochemical industries for production of limited chemicals such as urea. The utilization of carbon dioxide does not necessarily involve development of new processes, and in certain processes such as methanol synthesis and methane steam reforming, addition of CO2 into the feed results in its utilization and increases carbon efficiency. In other cases, modifications in catalyst and/or processes, or even new catalysts and processes, are necessary. In either case, catalysis plays a crucial role in carbon dioxide conversion and effective catalysts are required for commercial realization of the related processes. Technologies for CO2 utilization are emerging after many years of research and development efforts.展开更多
The efficient development and exploitation of shale oil depends on long-distance horizontal wells. As the degreeof cleaning of the wellbore plays a key role in these processes, in this study, this problem is investiga...The efficient development and exploitation of shale oil depends on long-distance horizontal wells. As the degreeof cleaning of the wellbore plays a key role in these processes, in this study, this problem is investigated experimentallyby focusing on the dimensionless cuttings bed height. A method is proposed to calculate the horizontalwellhydraulic extension taking into account the influence of the wellbore cleaning degree on the wellborepressure distribution and assess the effect of a variety of factors such as the bottom hole pressure, the circulatingpressure drop, the drilling pump performance and the formation properties. The analysis shows that the hydraulicextension of horizontal wells decreases with an increase in the cuttings bed height, and the higher the displacementof drilling fluid, the faster the hydraulic extension declines. The annular pressure drop of the horizontalsection increases with the increase of the cuttings bed height, resulting in a higher bottom-hole pressure. Severalarguments are provided to guide the safe drilling of shale oil horizontal wells and overcome the limits of currenttechnological approaches.展开更多
BACKGROUND The Cariostat caries activity test(CAT)was used to evaluate the effectiveness of personalized oral hygiene management combining oral health education and professional mechanical tooth cleaning on the oral h...BACKGROUND The Cariostat caries activity test(CAT)was used to evaluate the effectiveness of personalized oral hygiene management combining oral health education and professional mechanical tooth cleaning on the oral health status of pregnant women.AIM To investigate whether personalized oral hygiene management enhances the oral health status of pregnant women.METHODS A total of 114 pregnant women who were examined at Dalian Women’s and Children’s Medical Center were divided into four groups:High-risk experimental group(n=29;CAT score≥2;received personalized oral hygiene management training),low-risk experimental group(n=29;CAT score≤1;received oral health education),high-risk control group(n=28;CAT score≥2),and low-risk control group(n=28;CAT score≤1).No hygiene intervention was provided to control groups.CAT scores at different times were compared using independent samples t-test and least significant difference t-test.RESULTS No significant difference in baseline CAT scores was observed between the experimental and control groups,either in the high-risk or low-risk groups.CAT scores were reduced significantly after 3(1.74±0.47 vs 2.50±0.38,P<0.0001)and 6 months(0.53±0.50 vs 2.45±0.42,P<0.0001)of personalized oral hygiene management intervention but not after oral health education alone(0.43±0.39 vs 0.46±0.33,P>0.05 and 0.45±0.36 vs 0.57±0.32,P>0.05,respectively).Within groups,the decrease in CAT scores was significant(2.43±0.44 vs 1.74±0.47 vs 0.53±0.50,P<0.0001)for only the high-risk experimental group.CONCLUSION Personalized oral hygiene management is effective in improving the oral health of pregnant women and can improve pregnancy outcomes and the oral health of the general population.展开更多
The Clean Development Mechanism,a flexibility mechanism contained in the KyotoProtocol, offers China an important tool to attractinvestment in clean energy technology and processesinto its electricity sector. The Chin...The Clean Development Mechanism,a flexibility mechanism contained in the KyotoProtocol, offers China an important tool to attractinvestment in clean energy technology and processesinto its electricity sector. The Chinese electricitysector places centrally in the country’s economy andenvironment, being a significant contributor to theacid rain and air pollution problems that plague manyof China’s cities and regions, and therefore a focusof many related energy and environmental policies.China’s electricity sector has also been the subjectof a number of economic analyses that have showedthat it contains the highest potential for clean energyinvestment through the Clean DevelopmentMechanism of any economic sector in China. Thismechanism, through the active participation frominvestors in more industrialized countries, can helpalleviate the environmental problems attributable toelectricity generation in China through advancingsuch technology as wind electricity generation, cleancoal technology, high efficient natural gas electricitygeneration, or utilization of coal mine methane. Inthis context, the Clean Development Mechanismalso compliments a range of environmental and energypolicies which are strategizing to encourage thesustainable development of China’s economy.展开更多
A generation planning model of six main power grids in China is developed to evaluate the potential of advanced power generation technologies into the Chinese power system as CDM (clean development mechanism). It is...A generation planning model of six main power grids in China is developed to evaluate the potential of advanced power generation technologies into the Chinese power system as CDM (clean development mechanism). It is investigated how delivered coal price, on-grid power price, and environmental protection may influence the potential of advanced thermal power generation as CDM projects. One finding from the baseline analysis is that coal price, on-grid power price, and environmental protection policy have only a small significance to the grid-wide specific CO2 emissions of thermal power generation up to the year 2026, while the best thermal generation mix is influenced largely by environmental protection policy. And it is found that not only the price of CER (certified emission reduction) and the length of crediting period but also on-grid power price and the reduction of air pollutants in the baseline have a significant influence on the potential of the CDM activities.展开更多
Since the Clean Development Mechanism(CDM) under the Kyoto Protocol was initiated,China and India have overwhelmingly led other developing countries regarding CDM projects development.A comparative study of the CDM in...Since the Clean Development Mechanism(CDM) under the Kyoto Protocol was initiated,China and India have overwhelmingly led other developing countries regarding CDM projects development.A comparative study of the CDM in India and China is conducted as there are many similarities between both India and China with regard to the CDM implementation due to the fact that India is another major developing country with a large population and a potential source of GHG emissions rivaling China in the near future.Through examining the development of and legal issues for CDM projects in India,its experience and lessons regarding developing and managing CDM projects that China can critically learn are discussed.展开更多
Objective: To systematically review the effects of mechanical tongue cleaning on halitosis. Methods: Searching and collecting the RCTs about treatment combine with mechanical tongue cleaning from inception to May 20...Objective: To systematically review the effects of mechanical tongue cleaning on halitosis. Methods: Searching and collecting the RCTs about treatment combine with mechanical tongue cleaning from inception to May 2017 in the databases, like CNKI, VIE WanFang Data, PubMed, the Cumulative Index to Nursing and Allied Health Literature (C1NAHL), The Cochrane Library, Web of Science. Two reviewers screened the literatures according to inclusion and excluding criteria, extracted the data independenly, assessed bias risks. In case of disagreement, the discussion shall be settled by the third reviewer. Meta-analysis was conducted by RevMaxi 5.3. Results: A total of 4 RCTs with 185 vol- unteers were included. The results of Meta-analysis showed that treatment combine with mechanical tongue cleaning has an advantage over the control group in the levels of Winkel Tongue Coating Index (WTCI) [MD = 2.15, 95%CI(0.93,3.36), = 0.0006], Organoleptic Assessment (ORG) [MD = -0.71, 95%CI(-0.95,-0.48), 〈0.00001], but no significant differences between two groups in Volatile Sulphur Compounds (VSCs) [SMD = -1.13, 95%CI(-2.91,0.65), = 0.21], Bleeding On Probing (BOP) [MD = -1.01, 95%CI(-7.05,5.03), = 0.74]. Conclusion: Treatment combined with mechanical tongue cleaning could reduce risks of halitosis and WTCI.展开更多
Global climate change has been identified as the first of the top ten environmental problems in the world. As climate change will have serious effects on the social and economic development and everyday, living of peo...Global climate change has been identified as the first of the top ten environmental problems in the world. As climate change will have serious effects on the social and economic development and everyday, living of people in the world, many of the countries and governments are taking untiring efforts to combat climate change. As one of the important mechanisms of reducing greenhouse gas (GHG) emissions in the Kyoto Protocol, Clean Development Mechanism (CDM) has not only provided chance for developed countries to fulfill greenhouse emission reduction obligations, but also provided an opportunity for developing countries to combat climate change under the sustainable development frame. The dual objectives of developed countries' GHG emissions' reduction obligation achievement and developing cotmtries'sustainable development will be achieved under the CDM. As a country with responsibility; China has been positively developing CDM projects and promoting energy saving and emissions reduction during the three yeors after the Kyoto Protocol came into force, and CDM projects development has always been in the front tank in the world. However; as the vast clime within China, notable differences occur in different regions. In order to promote the CDM development in China, it is necessa^T to have regional CDM capability construction in accordance with the practicality in different regions. Based on the Slat Analysis of developed CDM projects and current CDM development status in China, problems in the CDM development of China, including the inefficiency in small and medium-sized CDM Projects' development, over centralization of CDM development scope and especially the differentiated provincial CDM projects developing capability are pointed out in the paper: What's more, reasons for the problems are analyzed from fire leading.factors, including policy orient, information asymmetry and weak CDM capability, In order to promote CDM projects development in China, a new CDM capability, construction model is put forward in the paper.展开更多
Estimating CO2 emission factor of the electricity system is a key aspect in the calculation of the baseline emissions for projects certified as CDM (Clean Development Mechanism), which replace energy from the grid. ...Estimating CO2 emission factor of the electricity system is a key aspect in the calculation of the baseline emissions for projects certified as CDM (Clean Development Mechanism), which replace energy from the grid. Currently, Uruguay is driving the expansion of the electricity system based on domestic renewable energies, in addition to replacing oil-based fuels for others with lower emission factors. This implies a substantial change of the generation park in the next decade and of the associated CO2 emissions. In this paper, a calculation methodology of the baseline emissions is adapted for its incorporation in the software SimSEE (Electric Energy Systems Simulator), which is used for modeling the Uruguayan electric system, and therefore, allows modeling the current energy generator park and the future one. Using this tool, the CO2 emission factor's evolution is evaluated in the 2012-2020 period. The 2020 scenario is based on an optimal expansion of the electric system. The results indicate a strong reduction of the emission factor between 2012 and 2020, going from average values (for 100 simulations) around 0.60 tCO2/MWh to 0.15 tCO2/MWh. In this possible future scenario, CDM certification will probably not act as a strong incentive in Uruguay for the development of projects based on non-traditional renewable energies.展开更多
This study examines the effects of the inclusion of co-benefits on the potential capacity of advanced thermal plants with a linear programming model in the CDM (clean development mechanism) in India's power sector....This study examines the effects of the inclusion of co-benefits on the potential capacity of advanced thermal plants with a linear programming model in the CDM (clean development mechanism) in India's power sector. It investigates how different marginal damage costs of air pollutants affect the potential capacity of NGCC (natural gas combined cycle) and IGCC (integrated gasification combined cycle) by CDM projects with a scenario analysis. Three results are found from this analysis. First, IGCC and NGCC are installed at lower CER (certified emission reductions) prices when the marginal damage costs of air pollutants are added to the CER prices. Second, the CER prices of $1/tCO2 correspond with the sum of marginal damage costs of air pollutants of $150/t for NGCC and $30/t for IGCC in India's power sector. Thus, including the co-benefits into CDM attracts developing countries such as India where coal resource is redundant. Third, the SOx and NOx reduction benefits attained from the CDM projects become large in a grid where IGCC is installed.展开更多
Based on the status and characteristics of Clean Development Mechanism (CDM) renewable energy project and the mode of cyclic economy, aimed at achieving the maximum capacity of carbon sinks in the system, Lvjin Jiay...Based on the status and characteristics of Clean Development Mechanism (CDM) renewable energy project and the mode of cyclic economy, aimed at achieving the maximum capacity of carbon sinks in the system, Lvjin Jiayuan—New Countryside Distripark CDM project in Wuchuan County was taken as an example for developing an interval linear programming (ILP) model to optimize the crops planting scheme and cows breeding scheme by using interval optimal method. The case showed that the optimized crops planting scheme and cows breeding scheme obtained from the optimal model was reasonable with relatively preferable overall performance. In the context of meeting economic benefits and fertilizer, electricity demand, [231 287.8, 273 312.7] t of CO2 could be absorbed and fixed, which had increased by [12.94, 33.46]% compared with the feasibility scheme of case project and provided technical support for making the decision in CDM project.展开更多
The high quality of filler metals are required by the equipment manufacturing industry to obtain the high- performance brazed joint. For the problems of impurities in filler metal, the concept of entropy has been carr...The high quality of filler metals are required by the equipment manufacturing industry to obtain the high- performance brazed joint. For the problems of impurities in filler metal, the concept of entropy has been carried out to describe the cleanness of filler metal. The math expressions of process entropy, Sp, and performance entropy, Sf , have been presented. Sp characterizes the manufacturability of filler metal, corresponding to the spreading coefficient and the viscosity. SI characterizes the mechanical property of the brazed joint, corresponding to the tensile strength and the shear strength. With the inerease of entropy value, the cleanness as well as the brazability of filler metal and the mechanical property of joint deteriorate. The physical verification indicates that the expressions of St, and Sf could characterize the cleanness of filler metal.展开更多
The iron tailings of Bayan Obo mines are solid waste,which occupies land area and also causes environmental pollution;however,this waste can be recycled.In this study,based on the characteristics of iron minerals and ...The iron tailings of Bayan Obo mines are solid waste,which occupies land area and also causes environmental pollution;however,this waste can be recycled.In this study,based on the characteristics of iron minerals and fluorocarbonate contained in Bayan Obo iron tailings,clean magnetization roasting of iron minerals by bastnaesite from iron tailings during in-situ suspension magnetization roasting in a neutral atmosphere was explored.The results show that for iron tailings with a mass of 12 g,a N_(2) gas flow rate of 600 mL/min,and roasting for 5 min at 800℃,iron concentrate with a 60.44%iron grade at an iron recovery of 76.04%could be obtained.X-ray diffraction analysis showed that the weak magnetic hematite was reduced to strong magnetic magnetite in the neutral atmosphere,without additional reductant.The kinetics of the magnetization roasting of mineral mixtures(bastnaesite and hematite)in a neutral atmosphere showed that the optimal reaction mechanism function was the three-dimensional diffusion model with activation energy of 161.8838 kJ·mol^(-1);this indicates that the reaction was a heterogeneous,diffusion-controlled solid-state reaction.展开更多
Clean Development Mechanism (CDM) has given birth to an international carbon trading market prosperity, which provides developing countries with valuable opportunity to address climate change issues right along with e...Clean Development Mechanism (CDM) has given birth to an international carbon trading market prosperity, which provides developing countries with valuable opportunity to address climate change issues right along with economic development and environmental improvement to achieve sustainable development. However, most studies of CDM focus on economics, and few on its legal problems. CDM involves too many aspects. And the clear legal attribute of trading object is the basis of progress of the transaction and also the start point of legal protection. Therefore, this paper in accordance with the inherent principle of property rights economics, and environmental economics in CDM, only discusses CDM carbon emission right legal interpretation and its attribution. The paper recommends that in order to ensure and promote the carbon emission right trading, carbon emission right should be attributed into the system of real rights to be regulated by Real Right Law. In this way, carbon emission right can gain exclusive power of possession and use, which can achieve a clear right def inition of environmental goods in line with Coase's theory to protect Chinese prof it in carbon trading market and promote the development of the carbon trading market further.展开更多
基金National "863" Project of China (Grant no. 2007AA04Z224)
文摘A novel bionic swarm intelligence algorithm, called ant colony algorithm based on a blackboard mechanism, is proposed to solve the autonomy and dynamic deployment of mobiles sensor networks effectively. A blackboard mechanism is introduced into the system for making pheromone and completing the algorithm. Every node, which can be looked as an ant, makes one information zone in its memory for communicating with other nodes and leaves pheromone, which is created by ant itself in naalre. Then ant colony theory is used to find the optimization scheme for path planning and deployment of mobile Wireless Sensor Network (WSN). We test the algorithm in a dynamic and unconfigurable environment. The results indicate that the algorithm can reduce the power consumption by 13% averagely, enhance the efficiency of path planning and deployment of mobile WSN by 15% averagely.
基金Funded by the“Investigation and Evaluation of the Hot Dry Rock Resources in the Guide-Dalianhai Area of the Gonghe Basin,Qinghai”(DD20211336,DD20211337,DD20211338)“Hot Dry Rock Resources Exploration and Production Demonstration Project”(DD20230018)of the China Geological Survey。
文摘The Hot Dry Rock(HDR)is considered as a clean and renewable energy,poised to significantly contribute to the global energy decarbonization agenda.Many HDR projects worldwide have accumulated valuable experience in efficient drilling and completion,reservoir construction,and fracture simulation.In 2019,China Geological Survey(CGS)initiated a demonstration project of HDR exploration and production in the Gonghe Basin,aiming to overcome the setbacks faced by HDR projects.Over the ensuing four years,the Gonghe HDR project achieved the first power generation in 2021,followed by the second power generation test in 2022.After establishing the primary well group in the initial phase,two directional wells and one branch well were drilled.Noteworthy progress was made in successfully constructing the targeted reservoir,realizing inter-well connectivity,power generation and grid connection,implementing of the real-time micro-seismic monitoring.A closed-loop technical validation of the HDR exploration and production was completed.However,many technical challenges remain in the process of HDR industrialization,such as reservoir fracture network characterization,efficient drilling and completion,multiple fracturing treatment,continuous injection and production,as well as mitigation of induced seismicity and numerical simulation technology.
基金Project BK2008128 supported by the Natural Science Foundation of Jiangsu Province
文摘Concrete structures in main coal cleaning plants have been rebuilt and reinforced in the coal mines of the Shanghai Datun Energy Sources Co. Ltd., the first colliery of the Pingdingshan Coal Co. Ltd. and the Sanhejian mine of the Xuzhou Mining Group Co. Ltd. In these projects, the operating environment and reliability of concrete structures in the main plants of the three companies were investigated and the safety of the structures inspected. Qualitative and quantitative analyses were made on the special natural, technological and mechanical environments around the structures. On the basis of these analyses, we discuss the long-term, combined actions of the harsh natural (corrosive gases, liquids and solids) and mechanical environments on concrete structures and further investigated the damage and deteriorating mechanisms and curing techniques of concrete structures in the main coal cleaning plants. Our study can provide a theoretical basis for ensuring the reliability of concrete structures in main coal cleaning plants.
文摘This paper summarizes the results of the implementation of the CDM in Argentina during the first period of commitment of the Kyoto Protocol. From a total of sixty- five projects ideas, forty-four achieved registration under the CDM EB while the rest remained approved at national level (12), under evaluation (2), suspended (5) or rejected (2). Most of the projects focused on the generation of electricity from renewable energy, mainly wind energy and the use of landfill gas and methane for energy. Emissions reductions achieved 33.4% of the expected CERs up to 2012 with strong differences among sectors. Results demonstrated that under the current Argentina’s energy policy framework, the income by the selling of CERs covered less than 6% of the incremental costs for renewable energy projects. A sensitivity analysis to evaluate the impact of CDM in the coverage of incremental costs for renewable energy based on the prices of both the energy in the local market and the CER demonstrated that the best conditions would only cover 15% of those costs. The contribution of CDM to technology transfer in Argentina was minor considering that 45% of the projects qualified as type III where technological learning and capacity building were limited at the level of operation and maintenance of a foreign technology. Domestic and external barriers that prevented a better performance of CDM projects in terms of GHG mitigation, technology transfer and the contribution to a sustainable development were also analyzed.
文摘The increase of atmospheric carbon dioxide and the global warming due to its greenhouse effect resulted in worldwide concerns. On the other hand, carbon dioxide might be considered as a valuable and renewable carbon source. One approach to reduce carbon dioxide emissions could be its capture and recycle via transformation into chemicals using the technologies in C1 chemistry. Despite its great interest, there are difficulties in CO2 separation on the one hand, and thermodynamic stability of carbon dioxide molecule rendering its chemical activity low on the other hand. Carbon dioxide has been already used in petrochemical industries for production of limited chemicals such as urea. The utilization of carbon dioxide does not necessarily involve development of new processes, and in certain processes such as methanol synthesis and methane steam reforming, addition of CO2 into the feed results in its utilization and increases carbon efficiency. In other cases, modifications in catalyst and/or processes, or even new catalysts and processes, are necessary. In either case, catalysis plays a crucial role in carbon dioxide conversion and effective catalysts are required for commercial realization of the related processes. Technologies for CO2 utilization are emerging after many years of research and development efforts.
基金supported by CNPC Key Core Technology Research Projects (2022ZG06)project funded by China Postdoctoral Science Foundation (2021M693508)Basic research and strategic reserve technology research fund project of institutes directly under CNPC.
文摘The efficient development and exploitation of shale oil depends on long-distance horizontal wells. As the degreeof cleaning of the wellbore plays a key role in these processes, in this study, this problem is investigated experimentallyby focusing on the dimensionless cuttings bed height. A method is proposed to calculate the horizontalwellhydraulic extension taking into account the influence of the wellbore cleaning degree on the wellborepressure distribution and assess the effect of a variety of factors such as the bottom hole pressure, the circulatingpressure drop, the drilling pump performance and the formation properties. The analysis shows that the hydraulicextension of horizontal wells decreases with an increase in the cuttings bed height, and the higher the displacementof drilling fluid, the faster the hydraulic extension declines. The annular pressure drop of the horizontalsection increases with the increase of the cuttings bed height, resulting in a higher bottom-hole pressure. Severalarguments are provided to guide the safe drilling of shale oil horizontal wells and overcome the limits of currenttechnological approaches.
基金Dalian Science and Technology Plan Project,No 2022080102.
文摘BACKGROUND The Cariostat caries activity test(CAT)was used to evaluate the effectiveness of personalized oral hygiene management combining oral health education and professional mechanical tooth cleaning on the oral health status of pregnant women.AIM To investigate whether personalized oral hygiene management enhances the oral health status of pregnant women.METHODS A total of 114 pregnant women who were examined at Dalian Women’s and Children’s Medical Center were divided into four groups:High-risk experimental group(n=29;CAT score≥2;received personalized oral hygiene management training),low-risk experimental group(n=29;CAT score≤1;received oral health education),high-risk control group(n=28;CAT score≥2),and low-risk control group(n=28;CAT score≤1).No hygiene intervention was provided to control groups.CAT scores at different times were compared using independent samples t-test and least significant difference t-test.RESULTS No significant difference in baseline CAT scores was observed between the experimental and control groups,either in the high-risk or low-risk groups.CAT scores were reduced significantly after 3(1.74±0.47 vs 2.50±0.38,P<0.0001)and 6 months(0.53±0.50 vs 2.45±0.42,P<0.0001)of personalized oral hygiene management intervention but not after oral health education alone(0.43±0.39 vs 0.46±0.33,P>0.05 and 0.45±0.36 vs 0.57±0.32,P>0.05,respectively).Within groups,the decrease in CAT scores was significant(2.43±0.44 vs 1.74±0.47 vs 0.53±0.50,P<0.0001)for only the high-risk experimental group.CONCLUSION Personalized oral hygiene management is effective in improving the oral health of pregnant women and can improve pregnancy outcomes and the oral health of the general population.
文摘The Clean Development Mechanism,a flexibility mechanism contained in the KyotoProtocol, offers China an important tool to attractinvestment in clean energy technology and processesinto its electricity sector. The Chinese electricitysector places centrally in the country’s economy andenvironment, being a significant contributor to theacid rain and air pollution problems that plague manyof China’s cities and regions, and therefore a focusof many related energy and environmental policies.China’s electricity sector has also been the subjectof a number of economic analyses that have showedthat it contains the highest potential for clean energyinvestment through the Clean DevelopmentMechanism of any economic sector in China. Thismechanism, through the active participation frominvestors in more industrialized countries, can helpalleviate the environmental problems attributable toelectricity generation in China through advancingsuch technology as wind electricity generation, cleancoal technology, high efficient natural gas electricitygeneration, or utilization of coal mine methane. Inthis context, the Clean Development Mechanismalso compliments a range of environmental and energypolicies which are strategizing to encourage thesustainable development of China’s economy.
文摘A generation planning model of six main power grids in China is developed to evaluate the potential of advanced power generation technologies into the Chinese power system as CDM (clean development mechanism). It is investigated how delivered coal price, on-grid power price, and environmental protection may influence the potential of advanced thermal power generation as CDM projects. One finding from the baseline analysis is that coal price, on-grid power price, and environmental protection policy have only a small significance to the grid-wide specific CO2 emissions of thermal power generation up to the year 2026, while the best thermal generation mix is influenced largely by environmental protection policy. And it is found that not only the price of CER (certified emission reduction) and the length of crediting period but also on-grid power price and the reduction of air pollutants in the baseline have a significant influence on the potential of the CDM activities.
基金supported by the MOE (Ministry of Education in China) Project of Humanities and Social Sciences (Project No.11YJC820045)
文摘Since the Clean Development Mechanism(CDM) under the Kyoto Protocol was initiated,China and India have overwhelmingly led other developing countries regarding CDM projects development.A comparative study of the CDM in India and China is conducted as there are many similarities between both India and China with regard to the CDM implementation due to the fact that India is another major developing country with a large population and a potential source of GHG emissions rivaling China in the near future.Through examining the development of and legal issues for CDM projects in India,its experience and lessons regarding developing and managing CDM projects that China can critically learn are discussed.
文摘Objective: To systematically review the effects of mechanical tongue cleaning on halitosis. Methods: Searching and collecting the RCTs about treatment combine with mechanical tongue cleaning from inception to May 2017 in the databases, like CNKI, VIE WanFang Data, PubMed, the Cumulative Index to Nursing and Allied Health Literature (C1NAHL), The Cochrane Library, Web of Science. Two reviewers screened the literatures according to inclusion and excluding criteria, extracted the data independenly, assessed bias risks. In case of disagreement, the discussion shall be settled by the third reviewer. Meta-analysis was conducted by RevMaxi 5.3. Results: A total of 4 RCTs with 185 vol- unteers were included. The results of Meta-analysis showed that treatment combine with mechanical tongue cleaning has an advantage over the control group in the levels of Winkel Tongue Coating Index (WTCI) [MD = 2.15, 95%CI(0.93,3.36), = 0.0006], Organoleptic Assessment (ORG) [MD = -0.71, 95%CI(-0.95,-0.48), 〈0.00001], but no significant differences between two groups in Volatile Sulphur Compounds (VSCs) [SMD = -1.13, 95%CI(-2.91,0.65), = 0.21], Bleeding On Probing (BOP) [MD = -1.01, 95%CI(-7.05,5.03), = 0.74]. Conclusion: Treatment combined with mechanical tongue cleaning could reduce risks of halitosis and WTCI.
基金supported by National Key Project of ScientificTechnical Supporting Programs Funded by Ministry of Science & Technology of China in the 11th Five-Year Plan (Grant No.2007BAC03A04)
文摘Global climate change has been identified as the first of the top ten environmental problems in the world. As climate change will have serious effects on the social and economic development and everyday, living of people in the world, many of the countries and governments are taking untiring efforts to combat climate change. As one of the important mechanisms of reducing greenhouse gas (GHG) emissions in the Kyoto Protocol, Clean Development Mechanism (CDM) has not only provided chance for developed countries to fulfill greenhouse emission reduction obligations, but also provided an opportunity for developing countries to combat climate change under the sustainable development frame. The dual objectives of developed countries' GHG emissions' reduction obligation achievement and developing cotmtries'sustainable development will be achieved under the CDM. As a country with responsibility; China has been positively developing CDM projects and promoting energy saving and emissions reduction during the three yeors after the Kyoto Protocol came into force, and CDM projects development has always been in the front tank in the world. However; as the vast clime within China, notable differences occur in different regions. In order to promote the CDM development in China, it is necessa^T to have regional CDM capability construction in accordance with the practicality in different regions. Based on the Slat Analysis of developed CDM projects and current CDM development status in China, problems in the CDM development of China, including the inefficiency in small and medium-sized CDM Projects' development, over centralization of CDM development scope and especially the differentiated provincial CDM projects developing capability are pointed out in the paper: What's more, reasons for the problems are analyzed from fire leading.factors, including policy orient, information asymmetry and weak CDM capability, In order to promote CDM projects development in China, a new CDM capability, construction model is put forward in the paper.
文摘Estimating CO2 emission factor of the electricity system is a key aspect in the calculation of the baseline emissions for projects certified as CDM (Clean Development Mechanism), which replace energy from the grid. Currently, Uruguay is driving the expansion of the electricity system based on domestic renewable energies, in addition to replacing oil-based fuels for others with lower emission factors. This implies a substantial change of the generation park in the next decade and of the associated CO2 emissions. In this paper, a calculation methodology of the baseline emissions is adapted for its incorporation in the software SimSEE (Electric Energy Systems Simulator), which is used for modeling the Uruguayan electric system, and therefore, allows modeling the current energy generator park and the future one. Using this tool, the CO2 emission factor's evolution is evaluated in the 2012-2020 period. The 2020 scenario is based on an optimal expansion of the electric system. The results indicate a strong reduction of the emission factor between 2012 and 2020, going from average values (for 100 simulations) around 0.60 tCO2/MWh to 0.15 tCO2/MWh. In this possible future scenario, CDM certification will probably not act as a strong incentive in Uruguay for the development of projects based on non-traditional renewable energies.
文摘This study examines the effects of the inclusion of co-benefits on the potential capacity of advanced thermal plants with a linear programming model in the CDM (clean development mechanism) in India's power sector. It investigates how different marginal damage costs of air pollutants affect the potential capacity of NGCC (natural gas combined cycle) and IGCC (integrated gasification combined cycle) by CDM projects with a scenario analysis. Three results are found from this analysis. First, IGCC and NGCC are installed at lower CER (certified emission reductions) prices when the marginal damage costs of air pollutants are added to the CER prices. Second, the CER prices of $1/tCO2 correspond with the sum of marginal damage costs of air pollutants of $150/t for NGCC and $30/t for IGCC in India's power sector. Thus, including the co-benefits into CDM attracts developing countries such as India where coal resource is redundant. Third, the SOx and NOx reduction benefits attained from the CDM projects become large in a grid where IGCC is installed.
文摘Based on the status and characteristics of Clean Development Mechanism (CDM) renewable energy project and the mode of cyclic economy, aimed at achieving the maximum capacity of carbon sinks in the system, Lvjin Jiayuan—New Countryside Distripark CDM project in Wuchuan County was taken as an example for developing an interval linear programming (ILP) model to optimize the crops planting scheme and cows breeding scheme by using interval optimal method. The case showed that the optimized crops planting scheme and cows breeding scheme obtained from the optimal model was reasonable with relatively preferable overall performance. In the context of meeting economic benefits and fertilizer, electricity demand, [231 287.8, 273 312.7] t of CO2 could be absorbed and fixed, which had increased by [12.94, 33.46]% compared with the feasibility scheme of case project and provided technical support for making the decision in CDM project.
文摘The high quality of filler metals are required by the equipment manufacturing industry to obtain the high- performance brazed joint. For the problems of impurities in filler metal, the concept of entropy has been carried out to describe the cleanness of filler metal. The math expressions of process entropy, Sp, and performance entropy, Sf , have been presented. Sp characterizes the manufacturability of filler metal, corresponding to the spreading coefficient and the viscosity. SI characterizes the mechanical property of the brazed joint, corresponding to the tensile strength and the shear strength. With the inerease of entropy value, the cleanness as well as the brazability of filler metal and the mechanical property of joint deteriorate. The physical verification indicates that the expressions of St, and Sf could characterize the cleanness of filler metal.
基金the financial support from the National Natural Science Foundation of China(No.52174242)the Fundamental Research Funds for the Central Universities(No.180115008)the Fund of the Research Fund Program of State Key Laboratory of Rare Metals Separation and Comprehensive Utilization(No.GK-201804)。
文摘The iron tailings of Bayan Obo mines are solid waste,which occupies land area and also causes environmental pollution;however,this waste can be recycled.In this study,based on the characteristics of iron minerals and fluorocarbonate contained in Bayan Obo iron tailings,clean magnetization roasting of iron minerals by bastnaesite from iron tailings during in-situ suspension magnetization roasting in a neutral atmosphere was explored.The results show that for iron tailings with a mass of 12 g,a N_(2) gas flow rate of 600 mL/min,and roasting for 5 min at 800℃,iron concentrate with a 60.44%iron grade at an iron recovery of 76.04%could be obtained.X-ray diffraction analysis showed that the weak magnetic hematite was reduced to strong magnetic magnetite in the neutral atmosphere,without additional reductant.The kinetics of the magnetization roasting of mineral mixtures(bastnaesite and hematite)in a neutral atmosphere showed that the optimal reaction mechanism function was the three-dimensional diffusion model with activation energy of 161.8838 kJ·mol^(-1);this indicates that the reaction was a heterogeneous,diffusion-controlled solid-state reaction.
基金supported by National Key Project of Scientific and Technical Supporting Programs Funded by Ministry of Science and Tech-nology of China in the 11th Five-Year Plan (Grant No. 2007BAC03A12).
文摘Clean Development Mechanism (CDM) has given birth to an international carbon trading market prosperity, which provides developing countries with valuable opportunity to address climate change issues right along with economic development and environmental improvement to achieve sustainable development. However, most studies of CDM focus on economics, and few on its legal problems. CDM involves too many aspects. And the clear legal attribute of trading object is the basis of progress of the transaction and also the start point of legal protection. Therefore, this paper in accordance with the inherent principle of property rights economics, and environmental economics in CDM, only discusses CDM carbon emission right legal interpretation and its attribution. The paper recommends that in order to ensure and promote the carbon emission right trading, carbon emission right should be attributed into the system of real rights to be regulated by Real Right Law. In this way, carbon emission right can gain exclusive power of possession and use, which can achieve a clear right def inition of environmental goods in line with Coase's theory to protect Chinese prof it in carbon trading market and promote the development of the carbon trading market further.