The environmental load chart is an important technical support required for the jack-up drilling platform to facilitate its adaptation to different operating waters and ensure the safety of operation.This chart is a c...The environmental load chart is an important technical support required for the jack-up drilling platform to facilitate its adaptation to different operating waters and ensure the safety of operation.This chart is a crucial part of the platform operation manual.The chart data are closely related to external factors such as water depth,wind,wave,and current conditions of the working water,as well as to the structural characteristics of the platform itself and the number of variable loads.This study examines the platform state under extreme wind,wave,and current conditions during preloading.In addition,this study focuses on the difference between the ultimate reaction force of the pile leg during preloading and the reaction force of the pile leg without considering any environmental load before preloading.Furthermore,the relationship between the difference and the new reaction force of the pile leg caused by the combination of different environmental conditions is established to facilitate the construction of a new form of environmental load chart.The newly formed chart is flexible and simple;thus,it can be used to evaluate the environmental adaptability of the platform in the target well location and provides the preloading target demand or variable load limit according to the given environmental constraints.Moreover,the platform can perform personalized preloading operations,thereby improving its capability to cope with complex geological conditions,such as reducing punch-through risks.This condition reduces the load on jacking system devices and increases its service life.展开更多
The significant point is the bidirectional interaction technique in FSI analysis while investigating subsea corrosion effect. By this way, pipe environment is accurately modelled and fluid effects are also considered....The significant point is the bidirectional interaction technique in FSI analysis while investigating subsea corrosion effect. By this way, pipe environment is accurately modelled and fluid effects are also considered. The effect of external corrosion defects on structural behaviour of a pipeline is studied by creating a nonlinear numerical model based on the finite element method according to ABAQUS analysis program. Corrosion losses of sections are obtained from experimental results and applied to the model. Numerical model is formed by a span of sub-sea pipeline that is subjected to environmental loads. Seismic and wind-generated irregular wave loads are considered as environmental loads. Irregular wave is represented with equivalent eight regular waves via FFT. The pipe is modelled according to two different types which are non-corroded（intact） and corroded（deteriorated） to demonstrate corrosion effects on it. The visible type of corrosion in marine environment is named ‘pitting＇ corrosion, in which the material loss is locally interpenetrated over the surface. By considering this situation, the corroded and non-corroded pipes are modelled as 3D solid elements. The main point is revealing how the subsea corrosion affects the structural behaviour of pipelines on the basis of implementation of experimental results to a model structure due to changes of stresses and displacement.展开更多
With the development of ocean engineering, it is one of the most important factors which determine the structural safety, cost and suitable forms of engineerings to select the ocean environmental design criteria. Owin...With the development of ocean engineering, it is one of the most important factors which determine the structural safety, cost and suitable forms of engineerings to select the ocean environmental design criteria. Owing to the complexity , variation and randomness of ocean environmental conditions, the commonly used methods for determining design criteria cannot consider the joint occurring probabilities of several environmental factors ,therefore, lead to overestimate design criteria of them and result in an unnecessary overspend invest in engineering. On the basis of the measured and hindcasting data and the multi-demension joint probability theory, this paper presented the study of the joint loads of wind , wave and current on the offshore structures and its responsible joint probability level with the application of random simulation techniques, and presented the joint design criteria of environmental loads for the realistic design of engineerings.展开更多
Marine structures operating in natural ocean environment are subjected to various stochastic loads. For design of the marine structures, the most important task is to determine environmental load design criterion. Thi...Marine structures operating in natural ocean environment are subjected to various stochastic loads. For design of the marine structures, the most important task is to determine environmental load design criterion. This paper presents a method to determine the optimum environmental load design criterion for marine structures. This method is based on the investment and benefit analysis and it can reach the design purpose of decreasing total costs during the service life of the structures and increasing economic benefits.展开更多
The high environmental pollution load caused by the massive pollutant emissions and the accumulation of endogenous and cross-regional pollution has become an important obstacle to the current ecological civilization c...The high environmental pollution load caused by the massive pollutant emissions and the accumulation of endogenous and cross-regional pollution has become an important obstacle to the current ecological civilization construction in the Yangtze River Economic Belt(YREB)in China.Taking the YREB as an example,by using four environmental pollutant emission indicators,including chemical oxygen demand(COD),ammonia nitrogen(NH_(3)-N),sulfur dioxide(SO_(2)),and nitrogen oxides(NO_(x)),this paper established an environmental pollution load index(EPLI)based on the entropy-based measurement.Moreover,the Spatial Durbin Model was used to quantitatively analyze the drivers and spatial effects of environmental pollution load.Finally,specific scientific references were provided for formulating environmental regulations of pollution source control in the YREB.The results showed that:1)During2011-2015,the EPLI in the YREB was reduced significantly and the environmental pollution load increased from upstream to downstream.Among them,the pollution load levels in the Upper Mainstream subbasin,Taihu Lake subbasin,and Lower Mainstream subbasin were the most prominent.2)The environmental pollution load situation in the YREB was generally stable and partially improved.High load level areas were mainly concentrated in the Yangtze River Delta Region and the provincial borders in upstream,midstream,and downstream areas.The high load level areas already formed in Chengdu and Chongqing were also the key regulatory points in the future.3)The degree of local environmental pollution load was apparently affected by the adjacent cities.The population size,industrialization level,and the fiscal decentralization not only drove the increase of the local environmental pollution load level,but also affected the adjacent areas through the spatial spillover effects.The land development intensity mainly drove the increase in the local EPLI in the YREB.While factors such as economic development level and agricultural economic share could only act on the environmental pollution load process in adjacent cities.4)According to the differentiation characteristics of drivers of each city,the YREB was divided into seven zones based on k-medoids cluster method,and targeted zoning control policy recommendations for alleviating environmental pollution load in the YREB were proposed.展开更多
Assessment system of implicit environmental impacts was established including environmental impact indicator, resources consumption indicator and energy consumption indicator. The quantification of environmental impac...Assessment system of implicit environmental impacts was established including environmental impact indicator, resources consumption indicator and energy consumption indicator. The quantification of environmental impact indicators is based on the life cycle assessment system of the Society of Environmental Toxicology and Chemistry （SETAC） and the evaluation software BEES. Normalization reference values and weights of 12 categories of environmental impacts were identified, and the environmental impact indicators in the phases of raw material extraction, transportation, manufacturing, use and end of life were analyzed. By analyzing the environmental performance of a university refectory as a case study, it is demonstrated that human health, global wanning and acidification are the first three environmental impacts in 12 categories. The total implicit environmental impact load per square meter of this project is 18.448 × 10 ^-2 standard human equivalent weight. Moreover, 97.3% of total environmental impacts occur in the phase of raw material extraction.展开更多
This study of Mikasa City in 2001, which analyzed N flow between N production and N load in seven agricultural and settlement subsystems, i.e., paddy, onion, wheat, vegetable, dairy, chicken, and citizen subsystems, a...This study of Mikasa City in 2001, which analyzed N flow between N production and N load in seven agricultural and settlement subsystems, i.e., paddy, onion, wheat, vegetable, dairy, chicken, and citizen subsystems, aimed to compare N flow in each subsystem, to determine the main sources of the N load, and to evaluate the influence of agricultural production and food consumption on N cycling in a rural area. The results showed that in Mikasa city, 38.5% of the N load came from point sources and the remainder from non-point sources with intensive vegetable farming imparting a serious N load. Because of the internal N cycling in the dairy subsystem, chemical fertilizer application was reduced by 70.2%, and 23.72 Mg manure N was recycled to the field; therefore, the N utilization efficiency was raised from 18.1% to 35.1%. If all the manure N in the chicken subsystem was recycled, chemical fertilizer application would be reduced by 8.1% from the present level, and the point sources of N pollution would be reduced by 20.8%.展开更多
This study aims to reveal the mechanism that how the content of steel fibers and strength grades affect the macro performance of the ultra-high performance fiber reinforced cementitious composite （UHPFRCC） and to st...This study aims to reveal the mechanism that how the content of steel fibers and strength grades affect the macro performance of the ultra-high performance fiber reinforced cementitious composite （UHPFRCC） and to study the UHPFRCC durability under the combined effect of loads and environments. Three types of high and ultra-high performance fiber reinforced cement composites with different strength grades （100, 150, 200 MPa） and different steel fiber volume fractions （0%, 1%, 2%, 3%） are prepared. The main properties of mechanical performance and short-term durability are studied. A preloading frame is designed to apply a four- point load external flexural stress with a stress selection ratio of 0.5 for UHPFRCC150 specimens. The results show that the growth in strength grade with a proper content of steel fiber greatly increases the strength and toughness of the HPFRCC and the UHPFRCC while decreasing the dry-shrinkage ratio. For the loaded specimens, the existence of steel fiber can reduce the negative influence of tensile stress on the Cl- penetration resistance of the UHPFRCC in addition to improving its ability to resist the freeze-thaw damage.展开更多
The floating bridge bears the dead weight and live load with buoyancy,and has wide application prospect in deep-water transportation infrastructure.The structural analysis of floating bridge is challenging due to the ...The floating bridge bears the dead weight and live load with buoyancy,and has wide application prospect in deep-water transportation infrastructure.The structural analysis of floating bridge is challenging due to the complicated fluid-solid coupling effects of wind and wave.In this research,a novel time domain approach combining dynamic finite element method and state-space model(SSM)is established for the refined analysis of floating bridges.The dynamic coupled effects induced by wave excitation load,radiation load and buffeting load are carefully simulated.High-precision fitted SSMs for pontoons are established to enhance the calculation efficiency of hydrodynamic radiation forces in time domain.The dispersion relation is also introduced in the analysis model to appropriately consider the phase differences of wave loads on pontoons.The proposed approach is then employed to simulate the dynamic responses of a scaled floating bridge model which has been tested under real wind and wave loads in laboratory.The numerical results are found to agree well with the test data regarding the structural responses of floating bridge under the considered environmental conditions.The proposed time domain approach is considered to be accurate and effective in simulating the structural behaviors of floating bridge under typical environmental conditions.展开更多
A joint industry project on a full scale measurement of Fenjin FPSO,headed by Shanghai Jiao Tong University and sponsored by CNOOC,was initiated in October 2007 and has been going on for more than 25 months.The purpos...A joint industry project on a full scale measurement of Fenjin FPSO,headed by Shanghai Jiao Tong University and sponsored by CNOOC,was initiated in October 2007 and has been going on for more than 25 months.The purpose of the project is to measure and collect the motions in six-degrees of freedom of an FPSO,and to collect the environmental loads at the offshore oil-field.A motion data measuring system is designed and installed on the FPSO.Another environmental data measuring system is installed on a fixed jacket platform nearby.A large quantity of valuable first-hand data is obtained.With the data collected,motion characteristics of the FPSO in a long-term period are concluded.A short-term analysis for the FPSO in one of the typhoons is also completed.The mean periods of wave-frequency motions are calculated by the spectrum analysis.The tension loads of the mooring system,which is of great concern,are calculated by the decoupled technique.展开更多
For the low price of coal and ineffective environmental management in mining area, China is in the dilemma of the increasing coal demand and the serious environmental issues in mining area. The more coal that is expor...For the low price of coal and ineffective environmental management in mining area, China is in the dilemma of the increasing coal demand and the serious environmental issues in mining area. The more coal that is exported from a region, the more heavily it suffers from the environmental impacts of coal export. In this paper, the temporal and spatial process of exporting coal from Shanxi to other provinces of China is traced between 1975 and 2005. The coal net export of Shanxi increased to 370.69 million tonnes in 2005, representing an average annual growth rate of 7.5% from 1975 to 2005. With the increase of the amount of coal export from Shanxi, the Environmental Loads Transfer （ELT） that import provinces input to mining areas of Shanxi are rising. Effective means of internalizing the environmental externality of ELT lie in： 1） setting up a coal sustainable development fund to restore environment of coal mining area; 2） enforcing environment tax, financial transfer payment and transferring advantage technology of pollution reduction to coal export area; and 3） reducing coal regional flow by reducing coal demand from power generation and heating and other industries.展开更多
Daily and annual average atmospheric environmental capacity coefficient(A-value) sequences for China's Mainland are calculated from hourly data recorded at 378 ground stations over 1975–2014. A-values at differen...Daily and annual average atmospheric environmental capacity coefficient(A-value) sequences for China's Mainland are calculated from hourly data recorded at 378 ground stations over 1975–2014. A-values at different recurrence intervals are calculated by fitting the sequences to Pearson type III distribution curves. Based on these A-values and source-sink balance(reference concentration 100 μg m^(-3)), atmospheric environmental capacities at the recurrence intervals are calculated for all of China's Mainland and each provincial administrative region. The climate average atmospheric environmental capacity reference value for the entire mainland is 2.169×10~7 t yr^(-1). An urban atmospheric load index is defined for analyses of the impact of population density on the urban atmospheric environment. Analyses suggest that this index is also useful for differentiating whether air quality changes are attributable to varying meteorological conditions or variations of artificial emission rate.Equations guiding the control of unorganized emission sources are derived for preventing air quality deterioration during urban expansion and population concentration.展开更多
Iron ore sintering is an energy＇intensive process associated with emission of pollutants in iron and steel in- dustry. In order to comprehensively evaluate the environmental impacts of sintering, a detailed life cycl...Iron ore sintering is an energy＇intensive process associated with emission of pollutants in iron and steel in- dustry. In order to comprehensively evaluate the environmental impacts of sintering, a detailed life cycle assessment of a sintering plant was conducted. Life cycle inventory showed that, in the production of 1 t sinter ore, 241.53 kg CO2 , 22.68 kg CO, 0. 294 kg SO2 , 0.63 kg NO, , 1.18 /lg dioxin and 0.48 kg dust were discharged. Global war- ming potentials, acidification potentials, photochemical ozone creation potentials and human toxicity potentials were selected as four impact categories, and the evaluation index for the sintering plant was calculated as 3.45 × 10 ^-12. Fi nally, based on the environmental impact analysis, several measures of reducing environmental [oadings of the sinte- ring plant were provided, which included the utilization of denitrification equipment, recirculation of the hot waste gas and process improvement to reduce fuel consumption.展开更多
Terrible scenario for the future aspect of our society was issued by ＂The Limits to Growth＂. Basic problems that we confront are the restricted natural resources and the environment. Regarding the resources, the ove...Terrible scenario for the future aspect of our society was issued by ＂The Limits to Growth＂. Basic problems that we confront are the restricted natural resources and the environment. Regarding the resources, the overall average of the reserve/production ratio is predicted to fall below 10 years by 2040. Aggressive developments of mines based on the sense of urgency for metal resources cause strong conftiction with the environment and the people living there. Resultantly, urban mine becomes more realistic than before. From the view point of ecological foot print, 5.3 globes are needed if all the people living in the world attain the affluent life same as USA. On the other hand, it is clear that we can get larger utility by smaller goods if our scale of satisfaction is reduced. We have to notice that happiness is our ultimate purpose, economy and industry are intermediate, and natural resources support the all from the basis.展开更多
Knowledge of the sediment flux derived from different sources is critical for interpreting the sedimentary records associated with large river sedimentary systems. For the Changjiang River system, previous studies har...Knowledge of the sediment flux derived from different sources is critical for interpreting the sedimentary records associated with large river sedimentary systems. For the Changjiang River system, previous studies hardly focused on the sediment load from the adjacent Zhoushan Archipelago(ZA). Based on four prediction models, aiming to improve the understanding of the sediment load from the ZA during the Holocene, we show that the predicted sediment flux of the ZA ranges from ~0.7 to 26.5 Mt·yr^(-1), with an average value of 10.7 Mt·yr^(-1), and the islands with a relatively large area or high relief contribute greatly to the total flux. This sediment load is an order of magnitude lower than that of the Changjiang River, but it is similar to those of the local small rivers. Located in the core area of the southward dispersal path of the Changjiang River plume, the ZA also influences the sediment transport into Hangzhou Bay and over the Zhejiang-Fujian coastal seas. On the Holocene temporal scale, e.g., for the period from 6 ka BP to 2 ka BP, the sediments discharged from the ZA had a considerable effect on the shelf sedimentary system. This study provides evidence for an important role an archipelago can play in terms of sediment supply and transport in coastal and inner continental shelf regions.展开更多
In the structural design of a roller-compacted concrete pavement(RCCP), it is crucial to estimate strain and stress developments in the RCCP slab realistically. Since the RCCP mix uses less cement and lower amount of ...In the structural design of a roller-compacted concrete pavement(RCCP), it is crucial to estimate strain and stress developments in the RCCP slab realistically. Since the RCCP mix uses less cement and lower amount of water, shrinkage strain and concrete temperature during the hardening stage are expected to be reduced as compared to those of conventional concrete mixture, resulting in a reduction of the concrete early-age deformation and stress developments in the RCCP slab. In this paper, early-age concrete strain and stress developments in RCCP slab subjected to environmental loads were evaluated. A full-scale test section of RCCP under real climatic conditions was monitored. The early-age total strains,stress-independent strains, shrinkage strains, and coefficient of thermal expansion(CTE) of the RCCP were measured and analyzed. Using the results of measured strains, in-situ CTE and shrinkage strain, and temperature, the early-age concrete stress development is computed by incorporating a viscoelastic property of the early-age concrete. The results revealed that the shrinkage strain of the RCCP is quite low as compared to that of conventional concrete. The early-age stress developments in the RCCP slab are strongly governed by the thermal-induced stresses. Shrinkage-induced stresses were quite small and might be negligible in a preliminary estimation of early-age stress developments in the RCCP slab.展开更多
基金Supported by the National Natural Science Foundation of China Youth Fund under Grant No.51909148the Doctoral Research Initiation Fund of Shandong Jiaotong University under Grant No.BS2018001。
文摘The environmental load chart is an important technical support required for the jack-up drilling platform to facilitate its adaptation to different operating waters and ensure the safety of operation.This chart is a crucial part of the platform operation manual.The chart data are closely related to external factors such as water depth,wind,wave,and current conditions of the working water,as well as to the structural characteristics of the platform itself and the number of variable loads.This study examines the platform state under extreme wind,wave,and current conditions during preloading.In addition,this study focuses on the difference between the ultimate reaction force of the pile leg during preloading and the reaction force of the pile leg without considering any environmental load before preloading.Furthermore,the relationship between the difference and the new reaction force of the pile leg caused by the combination of different environmental conditions is established to facilitate the construction of a new form of environmental load chart.The newly formed chart is flexible and simple;thus,it can be used to evaluate the environmental adaptability of the platform in the target well location and provides the preloading target demand or variable load limit according to the given environmental constraints.Moreover,the platform can perform personalized preloading operations,thereby improving its capability to cope with complex geological conditions,such as reducing punch-through risks.This condition reduces the load on jacking system devices and increases its service life.
文摘The significant point is the bidirectional interaction technique in FSI analysis while investigating subsea corrosion effect. By this way, pipe environment is accurately modelled and fluid effects are also considered. The effect of external corrosion defects on structural behaviour of a pipeline is studied by creating a nonlinear numerical model based on the finite element method according to ABAQUS analysis program. Corrosion losses of sections are obtained from experimental results and applied to the model. Numerical model is formed by a span of sub-sea pipeline that is subjected to environmental loads. Seismic and wind-generated irregular wave loads are considered as environmental loads. Irregular wave is represented with equivalent eight regular waves via FFT. The pipe is modelled according to two different types which are non-corroded（intact） and corroded（deteriorated） to demonstrate corrosion effects on it. The visible type of corrosion in marine environment is named ‘pitting＇ corrosion, in which the material loss is locally interpenetrated over the surface. By considering this situation, the corroded and non-corroded pipes are modelled as 3D solid elements. The main point is revealing how the subsea corrosion affects the structural behaviour of pipelines on the basis of implementation of experimental results to a model structure due to changes of stresses and displacement.
文摘With the development of ocean engineering, it is one of the most important factors which determine the structural safety, cost and suitable forms of engineerings to select the ocean environmental design criteria. Owing to the complexity , variation and randomness of ocean environmental conditions, the commonly used methods for determining design criteria cannot consider the joint occurring probabilities of several environmental factors ,therefore, lead to overestimate design criteria of them and result in an unnecessary overspend invest in engineering. On the basis of the measured and hindcasting data and the multi-demension joint probability theory, this paper presented the study of the joint loads of wind , wave and current on the offshore structures and its responsible joint probability level with the application of random simulation techniques, and presented the joint design criteria of environmental loads for the realistic design of engineerings.
文摘Marine structures operating in natural ocean environment are subjected to various stochastic loads. For design of the marine structures, the most important task is to determine environmental load design criterion. This paper presents a method to determine the optimum environmental load design criterion for marine structures. This method is based on the investment and benefit analysis and it can reach the design purpose of decreasing total costs during the service life of the structures and increasing economic benefits.
基金Under the auspices of National Natural Science Foundation of China(No.41971164,41530634)Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA23020101)Second Tibetan Plateau Scientific Expedition and Research Program(No.2019QZKK0406)。
文摘The high environmental pollution load caused by the massive pollutant emissions and the accumulation of endogenous and cross-regional pollution has become an important obstacle to the current ecological civilization construction in the Yangtze River Economic Belt(YREB)in China.Taking the YREB as an example,by using four environmental pollutant emission indicators,including chemical oxygen demand(COD),ammonia nitrogen(NH_(3)-N),sulfur dioxide(SO_(2)),and nitrogen oxides(NO_(x)),this paper established an environmental pollution load index(EPLI)based on the entropy-based measurement.Moreover,the Spatial Durbin Model was used to quantitatively analyze the drivers and spatial effects of environmental pollution load.Finally,specific scientific references were provided for formulating environmental regulations of pollution source control in the YREB.The results showed that:1)During2011-2015,the EPLI in the YREB was reduced significantly and the environmental pollution load increased from upstream to downstream.Among them,the pollution load levels in the Upper Mainstream subbasin,Taihu Lake subbasin,and Lower Mainstream subbasin were the most prominent.2)The environmental pollution load situation in the YREB was generally stable and partially improved.High load level areas were mainly concentrated in the Yangtze River Delta Region and the provincial borders in upstream,midstream,and downstream areas.The high load level areas already formed in Chengdu and Chongqing were also the key regulatory points in the future.3)The degree of local environmental pollution load was apparently affected by the adjacent cities.The population size,industrialization level,and the fiscal decentralization not only drove the increase of the local environmental pollution load level,but also affected the adjacent areas through the spatial spillover effects.The land development intensity mainly drove the increase in the local EPLI in the YREB.While factors such as economic development level and agricultural economic share could only act on the environmental pollution load process in adjacent cities.4)According to the differentiation characteristics of drivers of each city,the YREB was divided into seven zones based on k-medoids cluster method,and targeted zoning control policy recommendations for alleviating environmental pollution load in the YREB were proposed.
基金The Research Fund for the Doctoral Pro-gram of Higher Education of China(No.20050487017)
文摘Assessment system of implicit environmental impacts was established including environmental impact indicator, resources consumption indicator and energy consumption indicator. The quantification of environmental impact indicators is based on the life cycle assessment system of the Society of Environmental Toxicology and Chemistry （SETAC） and the evaluation software BEES. Normalization reference values and weights of 12 categories of environmental impacts were identified, and the environmental impact indicators in the phases of raw material extraction, transportation, manufacturing, use and end of life were analyzed. By analyzing the environmental performance of a university refectory as a case study, it is demonstrated that human health, global wanning and acidification are the first three environmental impacts in 12 categories. The total implicit environmental impact load per square meter of this project is 18.448 × 10 ^-2 standard human equivalent weight. Moreover, 97.3% of total environmental impacts occur in the phase of raw material extraction.
基金Project supported by the Science Research Foundation, Japan (No. 11460028).
文摘This study of Mikasa City in 2001, which analyzed N flow between N production and N load in seven agricultural and settlement subsystems, i.e., paddy, onion, wheat, vegetable, dairy, chicken, and citizen subsystems, aimed to compare N flow in each subsystem, to determine the main sources of the N load, and to evaluate the influence of agricultural production and food consumption on N cycling in a rural area. The results showed that in Mikasa city, 38.5% of the N load came from point sources and the remainder from non-point sources with intensive vegetable farming imparting a serious N load. Because of the internal N cycling in the dairy subsystem, chemical fertilizer application was reduced by 70.2%, and 23.72 Mg manure N was recycled to the field; therefore, the N utilization efficiency was raised from 18.1% to 35.1%. If all the manure N in the chicken subsystem was recycled, chemical fertilizer application would be reduced by 8.1% from the present level, and the point sources of N pollution would be reduced by 20.8%.
基金The Technical Research Program from NV Bekaert SA of Belgium (No. 8612000003)the National Natural Science Foundation of China (No. 50908047)
文摘This study aims to reveal the mechanism that how the content of steel fibers and strength grades affect the macro performance of the ultra-high performance fiber reinforced cementitious composite （UHPFRCC） and to study the UHPFRCC durability under the combined effect of loads and environments. Three types of high and ultra-high performance fiber reinforced cement composites with different strength grades （100, 150, 200 MPa） and different steel fiber volume fractions （0%, 1%, 2%, 3%） are prepared. The main properties of mechanical performance and short-term durability are studied. A preloading frame is designed to apply a four- point load external flexural stress with a stress selection ratio of 0.5 for UHPFRCC150 specimens. The results show that the growth in strength grade with a proper content of steel fiber greatly increases the strength and toughness of the HPFRCC and the UHPFRCC while decreasing the dry-shrinkage ratio. For the loaded specimens, the existence of steel fiber can reduce the negative influence of tensile stress on the Cl- penetration resistance of the UHPFRCC in addition to improving its ability to resist the freeze-thaw damage.
基金financially supported by the Program of Science and Technology Innovation Action Plan,Shanghai,China(Grant No.20200741600).
文摘The floating bridge bears the dead weight and live load with buoyancy,and has wide application prospect in deep-water transportation infrastructure.The structural analysis of floating bridge is challenging due to the complicated fluid-solid coupling effects of wind and wave.In this research,a novel time domain approach combining dynamic finite element method and state-space model(SSM)is established for the refined analysis of floating bridges.The dynamic coupled effects induced by wave excitation load,radiation load and buffeting load are carefully simulated.High-precision fitted SSMs for pontoons are established to enhance the calculation efficiency of hydrodynamic radiation forces in time domain.The dispersion relation is also introduced in the analysis model to appropriately consider the phase differences of wave loads on pontoons.The proposed approach is then employed to simulate the dynamic responses of a scaled floating bridge model which has been tested under real wind and wave loads in laboratory.The numerical results are found to agree well with the test data regarding the structural responses of floating bridge under the considered environmental conditions.The proposed time domain approach is considered to be accurate and effective in simulating the structural behaviors of floating bridge under typical environmental conditions.
基金supported by the National Scientific and Technology Major Project (Grant No.2008ZX05026-006)
文摘A joint industry project on a full scale measurement of Fenjin FPSO,headed by Shanghai Jiao Tong University and sponsored by CNOOC,was initiated in October 2007 and has been going on for more than 25 months.The purpose of the project is to measure and collect the motions in six-degrees of freedom of an FPSO,and to collect the environmental loads at the offshore oil-field.A motion data measuring system is designed and installed on the FPSO.Another environmental data measuring system is installed on a fixed jacket platform nearby.A large quantity of valuable first-hand data is obtained.With the data collected,motion characteristics of the FPSO in a long-term period are concluded.A short-term analysis for the FPSO in one of the typhoons is also completed.The mean periods of wave-frequency motions are calculated by the spectrum analysis.The tension loads of the mooring system,which is of great concern,are calculated by the decoupled technique.
基金Knowledge Innovation Project of Institute of Geographic Sciences and Natural Resources Research, CAS, No.O9V90143ZZ
文摘For the low price of coal and ineffective environmental management in mining area, China is in the dilemma of the increasing coal demand and the serious environmental issues in mining area. The more coal that is exported from a region, the more heavily it suffers from the environmental impacts of coal export. In this paper, the temporal and spatial process of exporting coal from Shanxi to other provinces of China is traced between 1975 and 2005. The coal net export of Shanxi increased to 370.69 million tonnes in 2005, representing an average annual growth rate of 7.5% from 1975 to 2005. With the increase of the amount of coal export from Shanxi, the Environmental Loads Transfer （ELT） that import provinces input to mining areas of Shanxi are rising. Effective means of internalizing the environmental externality of ELT lie in： 1） setting up a coal sustainable development fund to restore environment of coal mining area; 2） enforcing environment tax, financial transfer payment and transferring advantage technology of pollution reduction to coal export area; and 3） reducing coal regional flow by reducing coal demand from power generation and heating and other industries.
基金supported by the National Natural Science Foundation of China (Grant No. 41405136)
文摘Daily and annual average atmospheric environmental capacity coefficient(A-value) sequences for China's Mainland are calculated from hourly data recorded at 378 ground stations over 1975–2014. A-values at different recurrence intervals are calculated by fitting the sequences to Pearson type III distribution curves. Based on these A-values and source-sink balance(reference concentration 100 μg m^(-3)), atmospheric environmental capacities at the recurrence intervals are calculated for all of China's Mainland and each provincial administrative region. The climate average atmospheric environmental capacity reference value for the entire mainland is 2.169×10~7 t yr^(-1). An urban atmospheric load index is defined for analyses of the impact of population density on the urban atmospheric environment. Analyses suggest that this index is also useful for differentiating whether air quality changes are attributable to varying meteorological conditions or variations of artificial emission rate.Equations guiding the control of unorganized emission sources are derived for preventing air quality deterioration during urban expansion and population concentration.
基金Sponsored by Key Project in National Science and Technology Pillar Program during Twelfth Five-year Plan Period of China(2011BAF18B01)Hunan Platform of Youth Science and Technology Innovation and Entrepreneur(2014)
文摘Iron ore sintering is an energy＇intensive process associated with emission of pollutants in iron and steel in- dustry. In order to comprehensively evaluate the environmental impacts of sintering, a detailed life cycle assessment of a sintering plant was conducted. Life cycle inventory showed that, in the production of 1 t sinter ore, 241.53 kg CO2 , 22.68 kg CO, 0. 294 kg SO2 , 0.63 kg NO, , 1.18 /lg dioxin and 0.48 kg dust were discharged. Global war- ming potentials, acidification potentials, photochemical ozone creation potentials and human toxicity potentials were selected as four impact categories, and the evaluation index for the sintering plant was calculated as 3.45 × 10 ^-12. Fi nally, based on the environmental impact analysis, several measures of reducing environmental [oadings of the sinte- ring plant were provided, which included the utilization of denitrification equipment, recirculation of the hot waste gas and process improvement to reduce fuel consumption.
文摘Terrible scenario for the future aspect of our society was issued by ＂The Limits to Growth＂. Basic problems that we confront are the restricted natural resources and the environment. Regarding the resources, the overall average of the reserve/production ratio is predicted to fall below 10 years by 2040. Aggressive developments of mines based on the sense of urgency for metal resources cause strong conftiction with the environment and the people living there. Resultantly, urban mine becomes more realistic than before. From the view point of ecological foot print, 5.3 globes are needed if all the people living in the world attain the affluent life same as USA. On the other hand, it is clear that we can get larger utility by smaller goods if our scale of satisfaction is reduced. We have to notice that happiness is our ultimate purpose, economy and industry are intermediate, and natural resources support the all from the basis.
基金National Natural Science Foundation of China,No.41530962,No.41625021The National Basic Research Program of China,No.2013CB956500Natural Science Foundation of Jiangsu Province,No.BK20130056
文摘Knowledge of the sediment flux derived from different sources is critical for interpreting the sedimentary records associated with large river sedimentary systems. For the Changjiang River system, previous studies hardly focused on the sediment load from the adjacent Zhoushan Archipelago(ZA). Based on four prediction models, aiming to improve the understanding of the sediment load from the ZA during the Holocene, we show that the predicted sediment flux of the ZA ranges from ~0.7 to 26.5 Mt·yr^(-1), with an average value of 10.7 Mt·yr^(-1), and the islands with a relatively large area or high relief contribute greatly to the total flux. This sediment load is an order of magnitude lower than that of the Changjiang River, but it is similar to those of the local small rivers. Located in the core area of the southward dispersal path of the Changjiang River plume, the ZA also influences the sediment transport into Hangzhou Bay and over the Zhejiang-Fujian coastal seas. On the Holocene temporal scale, e.g., for the period from 6 ka BP to 2 ka BP, the sediments discharged from the ZA had a considerable effect on the shelf sedimentary system. This study provides evidence for an important role an archipelago can play in terms of sediment supply and transport in coastal and inner continental shelf regions.
基金supported by the Ministry of Land,Infrastructure and Transport(MOLIT),South Korea and the Korea Agency for Infrastructure Technology Advancement(KAIA),South Korea(project No:18TLRP-B146707-01)supported by the 2017 Academic Research Program funded by Gangneung-Wonju National University,South Korea。
文摘In the structural design of a roller-compacted concrete pavement(RCCP), it is crucial to estimate strain and stress developments in the RCCP slab realistically. Since the RCCP mix uses less cement and lower amount of water, shrinkage strain and concrete temperature during the hardening stage are expected to be reduced as compared to those of conventional concrete mixture, resulting in a reduction of the concrete early-age deformation and stress developments in the RCCP slab. In this paper, early-age concrete strain and stress developments in RCCP slab subjected to environmental loads were evaluated. A full-scale test section of RCCP under real climatic conditions was monitored. The early-age total strains,stress-independent strains, shrinkage strains, and coefficient of thermal expansion(CTE) of the RCCP were measured and analyzed. Using the results of measured strains, in-situ CTE and shrinkage strain, and temperature, the early-age concrete stress development is computed by incorporating a viscoelastic property of the early-age concrete. The results revealed that the shrinkage strain of the RCCP is quite low as compared to that of conventional concrete. The early-age stress developments in the RCCP slab are strongly governed by the thermal-induced stresses. Shrinkage-induced stresses were quite small and might be negligible in a preliminary estimation of early-age stress developments in the RCCP slab.
