Scallop culture is an important way of bottom-seeding marine ranching,which is of great significance to improve the current situation of fishery resources.However,there are some problems in site-selection evaluation o...Scallop culture is an important way of bottom-seeding marine ranching,which is of great significance to improve the current situation of fishery resources.However,there are some problems in site-selection evaluation of marine ranching,such as imperfect criteria system,complex structure,untargeted criteria quantification,etc.In addition,no site-selection evaluation method of bottom-seeding culture areas for scallops is available.Therefore,we established a hierarchy structure model according to the analytic hierarchy process(AHP)theory,in which social,physical,chemical,and biological environments are used as main criteria,and marine functional zonation,water depth,current,water temperature,salinity,substrate type,water quality,sediment quality,red tide,phytoplankton,and zooplankton are used as sub-criteria,on which a multi-parameter evaluation system is set up.Meanwhile,the dualism method,assignment method,and membership function method were used to quantify sub-criteria,and a quantitative evaluation for the entire criteria was added,including the evaluation and analysis of two types of unsuitable environmental situations.By overall consideration in scallop yield,quality,and marine ranching construction objectives,the weight of the main criteria could be determined.Five grades in the suitability corresponding to the evaluation result were divided,and the Python language was used to create an evaluation system for efficient calculation and intuitive presentation of the evaluation outcome.Eight marine cases were simulated based on existing survey data,and the results prove that the method is feasible for evaluating and analyzing the site selection of bottom-seeding culture areas for scallops under various environmental situations.The proposed evaluation method can be promoted for the site selection of bottom-seeding marine ranching.This study provided theoretical and methodological references for the site selection evaluation of other types of marine ranching.展开更多
A general prediction model for seven heavy metals was established using the heavy metal contents of 207soil samples measured by a portable X-ray fluorescence spectrometer(XRF)and six environmental factors as model cor...A general prediction model for seven heavy metals was established using the heavy metal contents of 207soil samples measured by a portable X-ray fluorescence spectrometer(XRF)and six environmental factors as model correction coefficients.The eXtreme Gradient Boosting(XGBoost)model was used to fit the relationship between the content of heavy metals and environment characteristics to evaluate the soil ecological risk of the smelting site.The results demonstrated that the generalized prediction model developed for Pb,Cd,and As was highly accurate with fitted coefficients(R^(2))values of 0.911,0.950,and 0.835,respectively.Topsoil presented the highest ecological risk,and there existed high potential ecological risk at some positions with different depths due to high mobility of Cd.Generally,the application of machine learning significantly increased the accuracy of pXRF measurements,and identified key environmental factors.The adapted potential ecological risk assessment emphasized the need to focus on Pb,Cd,and As in future site remediation efforts.展开更多
Groundwater vulnerability assessment is a crucial step in the efficient management of groundwater resources,especially in areas with intensive anthropogenic activities and groundwater pollution.In the present study,th...Groundwater vulnerability assessment is a crucial step in the efficient management of groundwater resources,especially in areas with intensive anthropogenic activities and groundwater pollution.In the present study,the DRASTIC method was applied using Geographic Information System(GIS)to delineate groundwater vulnerability zones in the Erbil Dumpsite area,Central Erbil Basin,North Iraq.Results showed that the area was classified into four vulnerability classes:Very low(16.97%),low(27.67%),moderate(36.55%)and high(18.81%).The southern,south-eastern and northern parts of the study area exhibited the highest vulnerability potential,while the central-northern,northern and north-western regions displayed the lowest vulnerability potential.Moreover,results of the single-parameter sensitivity analysis indicated that amongst the seven DRASTIC parameters,the unsaturated zone and the aquifer media were the most influencing parameters.In conclustion,the correlation of 25 nitrate concentration values with the final vulnerability map,assessed using the Pearson correlation coefficient,yielded a satisfactory result of R=0.72.展开更多
The total concentrations of Cd,As,Pb,Cr,Ni,Co,Zn,Cu,Ag,Hg,and Mo were determined in the atmospheric dust of the city of Yerevan by atomic absorption spectrometry(AAnalyst PE 800).Heavy metal pollution levels were eval...The total concentrations of Cd,As,Pb,Cr,Ni,Co,Zn,Cu,Ag,Hg,and Mo were determined in the atmospheric dust of the city of Yerevan by atomic absorption spectrometry(AAnalyst PE 800).Heavy metal pollution levels were evaluated by calculating geo-accumulation(I_(geo)) and summary pollution(Z_c) indices.Potential human health risk was assessed using the United States Environmental Protection agency's human health risk assessment model.The results show that mean contents of all elements tested except Ni and Cr were substantially higher than local geochemical background values.According to the I_(geo),Yerevan territory is strongly-to-extremely polluted by As,Ag,Hg,Mo,and Cd.The Z_c assessment indicated that very high pollution was detected in 36%of samples,high in 32%,average in 12%,and low in 20%.The health risk assessment revealed a noncarcinogenic risk(HI >1) for children at 13 samplings sites and for adults at one sampling site.For children the risk was due to elevated levels of Mo,Cd,Co,and As,while for adults,only Mo.Carcinogenic risk(>1:1,000,000) of As and Cr via ingestion pathway was observed in 25 and 14 samples,respectively.This study,therefore,is the base for further detailed investigations to organize problematic site remediation and risk reduction measures.展开更多
The seismic behavior of skewed bridges has not been well studied compared to straight bridges. Skewed bridges have shown extensive damage, especially due to deck rotation, shear keys failure, abutment unseating and co...The seismic behavior of skewed bridges has not been well studied compared to straight bridges. Skewed bridges have shown extensive damage, especially due to deck rotation, shear keys failure, abutment unseating and column- bent drift. This research, therefore, aims to study the behavior of skewed and straight highway overpass bridges both with and without taking into account the effects of Soil-Structure Interaction (SSI) due to near-fault ground motions. Due to several sources of uncertainty associated with the ground motions, soil and structure, a probabilistic approach is needed. Thus, a probabilistic methodology similar to the one developed by the Pacific Earthquake Engineering Research Center (PEER) has been utilized to assess the probability of damage due to various levels of shaking using appropriate intensity measures with minimum dispersions. The probabilistic analyses were performed for various bridge configurations and site conditions, including sand ranging from loose to dense and clay ranging from soft to stiff, in order to evaluate the effects. The results proved a considerable susceptibility of skewed bridges to deck rotation and shear keys displacement. It was also found that SSI had a decreasing effect on the damage probability for various demands compared to the fixed-base model without including SSI. However, deck rotation for all types of the soil and also abutment unseating for very loose sand and soft clay showed an increase in damage probability compared to the fixed-base model. The damage probability for various demands has also been found to decrease with an increase of soil strength for both sandy and clayey sites. With respect to the variations in the skew angle, an increase in skew angle has had an increasing effect on the amplitude of the seismic response for various demands. Deck rotation has been very sensitive to the increase in the skew angle; therefore, as the skew angle increased, the deck rotation responded accordingly. Furthermore, abutment unseating showed an increasing trend due to an increase in skew angle for both fixed-base and SSI models.展开更多
Ecological risk assessment(ERA) is an indispensable method for systematic monitoring of World Heritage Sites(WHSs) exposed to various anthropogenic factors and natural disasters. Remote sensing(RS) and geographical in...Ecological risk assessment(ERA) is an indispensable method for systematic monitoring of World Heritage Sites(WHSs) exposed to various anthropogenic factors and natural disasters. Remote sensing(RS) and geographical information systems(GIS) can eliminate many limitations in traditional ERA methods. In this study, changes in ecological risk at Huangshan Mountain, the first mixed WHS in China, over the period of 1984–2019 were explored using remote sensing images and products by considering both natural disasters and human disturbance. Results show that of the four land cover types in Huangshan Mountain, namely water, forest, building and farmland, the main land cover type is forest. During the 35 yr, lands categorised at low or relatively low ecological risk levels are dominant in Huangshan Mountain, with the lowest and highest ERIs(ecological risk index) in 1990 and 2010, respectively. The areas at the five ecological risk levels have declined as follows: relatively low > low > medium > relatively high > high. Changes in ecological risks are closely related to changes in land cover and natural disasters. Even though major natural disasters may affect the ecological risk level in the whole region, changes in land cover caused by human activities will shift the ecological risk level in some areas. Our attempts can be modified and applied to other sites, and offer policy implications for protection and preservation of WHSs.展开更多
A damage assessment methodology based on the Hashin failure theory for glass fiber reinforced polymer(GFRP)composite blade is proposed. The typical failure mechanisms including the fiber tension/compression and matrix...A damage assessment methodology based on the Hashin failure theory for glass fiber reinforced polymer(GFRP)composite blade is proposed. The typical failure mechanisms including the fiber tension/compression and matrix tension/compression are considered to describe the damage behaviors. To give the flapwise and edgewise loading along the blade span, the Blade Element Momentum Theory(BEMT) is adopted. In conjunction with the hydrodynamic analysis, the structural analysis of the composite blade is cooperatively performed with the Hashin damage model. The damage characteristics of the composite blade, under normal and extreme operational conditions,are comparatively analyzed. Numerical results demonstrate that the matrix tension damage is the most significant failure mode which occurs in the mid-span of the blade. The blade internal configurations including the box-beam, Ibeam, left-C beam and right-C beam are compared and analyzed. The GFRP and carbon fiber reinforced polymer(CFRP) are considered and combined. Numerical results show that the I-beam is the best structural type. The structural performance of composite tidal turbine blades could be improved by combining the GFRP and CFRP structure considering the damage and cost-effectiveness synthetically.展开更多
Fatigue strength assessment of a horizontal axis wind turbine(HAWT)composite blade is considered.Fatigue load cases are identified,and loads are calculated by the GH Bladed software which is specified at the IEC61400 ...Fatigue strength assessment of a horizontal axis wind turbine(HAWT)composite blade is considered.Fatigue load cases are identified,and loads are calculated by the GH Bladed software which is specified at the IEC61400 international specification and GL(Germanisher Lloyd)regulations for the wind energy conversion system.Stress analysis is performed with a 3-D finite element method(FEM).Considering Saint-Venant′s principle,a uniform cross section FEM model is built at each critical zone.Stress transformation matrixes(STM)are set up by applied six unit load components on the FEM model separately.STM can be used to convert the external load into stresses in the linear elastic range.The main material of composite wind turbine blade is fiber reinforced plastics(FRP).In order to evaluate the degree of fatigue damage of FRP,the stresses of fiber direction are extracted and the well-known strength criterion-Puck theory is used.The total fatigue damage of each laminate on the critical point is counted by the rain-flow counting method and Miner′s damage law based on general S-N curves.Several sections of a 45.3mblade of a 2 MW wind turbine are studied using the fatigue evaluation method.The performance of this method is compared with far more costly business software FOCUS.The results show that the fatigue damage of multi-axis FRP can be assessed conveniently by the FEM-STM method.And the proposed method gives a reliable and efficient method to analyze the fatigue damage of slender composite structure with variable cross-sections.展开更多
On August 8, 2017, a Ms = 7.0 magnitude earthquake occurred in the Jiuzhaigou Valley, in Sichuan Province, China(N: 33.20°, E: 103.82°). Jiuzhaigou Valley is an area recognized and listed as a world heritage...On August 8, 2017, a Ms = 7.0 magnitude earthquake occurred in the Jiuzhaigou Valley, in Sichuan Province, China(N: 33.20°, E: 103.82°). Jiuzhaigou Valley is an area recognized and listed as a world heritage site by UNESCO in 1992. Data analysis and field survey were conducted on the landslide, collapse, and debris flow gully, to assess the coseismic geological hazards generated by the earthquake using an unmanned aerial vehicle(UAV), remote-sensing imaging, laser range finders, geological radars, and cameras. The results highlighted the occurrence of 13 landslides, 70 collapses, and 25 potential debris flow gullies following the earthquake. The hazards were classified on the basis of their size and the potential property loss attributable to them. Consequently, 14 large-scale hazards, 30 medium-sized hazards, and 64 small hazards accounting for 13%, 28%, and 59% of the total hazards, respectively, were identified. Based on the variation tendency of the geological hazards that ensued in areas affected by the Kanto earthquake(Japan), Chi-chi earthquake(Taiwan China), and Wenchuan earthquake(Sichuan China), the study predicts that, depending on the rain intensity cycle, the duration of geological hazard activities in the Jiuzhaigou Valley may last over ten years and will gradually decrease for the following five to ten yearsbefore returning to pre-earthquake levels. Thus,necessary monitoring and early warning systems must be implemented to ensure the safety of residents,workers and tourists during the construction of engineering projects and reopening of scenic sites to the public.展开更多
This paper presents spatial variation of seismic hazard at the surface level for India,covering 6-38°N and 68-98°E.The most recent knowledge on seismic activity in the region has been used to evaluate the ha...This paper presents spatial variation of seismic hazard at the surface level for India,covering 6-38°N and 68-98°E.The most recent knowledge on seismic activity in the region has been used to evaluate the hazard incorporating uncertainties associated with the seismicity parameters using different modeling methodologies.Three types of seismic source models,viz.linear sources,gridded seismicity model and areal sources,were considered to model the seismic sources and different sets of ground motion prediction equations were used for different tectonic provinces to characterize the attenuation properties.The hazard estimation at bedrock level has been carried out using probabilistic approach and the results obtained from various methodologies were combined in a logic tree framework.The seismic site characterization of India was done using topographic slope map derived from Digital Elevation Model data.This paper presents estimation of the hazard at surface level,using appropriate site amplification factors corresponding to various site classes based on V_(S30) values derived from the topographic gradient.Spatial variation of surface level peak horizontal acceleration(PHA) for return periods of 475 years and 2475 years are presented as contour maps.展开更多
Limited information is available on long-term effects of metal(loid)s pollution incidents. Here, we analyze the distribution characteristics and quantification of elements in the Southwest China Keda mining site, whic...Limited information is available on long-term effects of metal(loid)s pollution incidents. Here, we analyze the distribution characteristics and quantification of elements in the Southwest China Keda mining site, which is one of the most populated sites and enables human health and ecological risk assessments of elemental pollution. The results on modified degree of contamination indicated that the soil and sediment were highly contaminated near Dahu Lake.The health risk of children was almost 2.5 times that of adults in surface water, and 7.1 times in soil, respectively.Moreover, Tl and As were the main health risk contributors in surface water and soil, respectively, and As posed the highest ecological risk both in soil and sediment. These results indicated the potential impact of toxic metal(loid)s on the health of residents and environment. Hence, more scientific attention and proper management need to be paid to this environmental challenge in the future.展开更多
Farmland protection and delimitation in the urban fringe considers not only natural factors but also the spatial characters and site factors. Taking Daxing District, Beijing in China as a case study, this paper used l...Farmland protection and delimitation in the urban fringe considers not only natural factors but also the spatial characters and site factors. Taking Daxing District, Beijing in China as a case study, this paper used landscape ecology and power-law methods to ana- lyze and evaluate farmland loss during the period of 2004~2007 based on the interpretation results of SPOT5 remote sensing images in 2004 and 2007. At the patch level, we selected four landscape indices, namely patch size, shape index, the nearest neighbor distance between farmland and construction land (including residential land and other construction land), and cropping type, to evaluate the risk of farmland loss and establish a farmland site analysis indicator system. The results showed that patch size and shape index have a sig- nificant positive correlation with farmland loss, whereas the distance to construction land has a clear negative correlation with farmland loss. As regards cropping type, fallow farmland is much easier for non-agriculUlral use than cultivated farmland. The relative transition ratio among vegetable land, fallow farmland and cultivated farmland is 1 : 5.6 : 1. The patch size of lost farmland follows a power-law distribution, indicating that not only small parcels but also large parcels can be lost. Patch size less than 4 ha or more than 15 ha is in high loss risk, between 4 ha and 10 ha in medium loss risk, and larger than 10 ha and less than 15 ha in low risk. Farmland with a more regular shape has a higher likelihood of loss. Patch shape index less than 2.0 is in high loss risk, between 2.0 and 3.0 in medium loss risk, and larger than 3.0 in low risk. Construction land has a varying impact on farmland loss, the residential land effeeted distance is 1000 m, and that of the other construction land is 2000 m. This analysis showed the relationships between site factors and farmland loss, and the analysis framework can provide support and reference for farmland protection and delimitation of prime farmland in China.展开更多
Creosote-treated wooden railroad crossties have been used for more than a century to support steel rails and to transfer load from the rails to the underlying ballast while keeping the rails at the correct gauge. As t...Creosote-treated wooden railroad crossties have been used for more than a century to support steel rails and to transfer load from the rails to the underlying ballast while keeping the rails at the correct gauge. As transportation engineers look for improved service life and environmental performance in railway systems, alternatives to the creosote-treated wooden crosstie are being considered. This paper compares the cradle-to-grave environmental life cycle assessment (LCA) results of creosote-treated wooden railroad crossties with the primary alternative products: concrete and plastic composite (P/C) crossties. This LCA includes a life cycle inventory (LCI) to catalogue the input and output data from crosstie manufacture, service life, and disposition, and a life cycle impact assessment (LCIA) to evaluate greenhouse gas (GHG) emissions, fossil fuel and water use, and emissions with the potential to cause acidification, smog, ecotoxicity, and eutrophication. Comparisons of the products are made at a functional unit of 1.61 kilometers (1.0 mile) of rail-road track per year. This LCA finds that the manufacture, use, and disposition of creosote-treated wooden railroad crossties offers lower fossil fuel and water use and lesser environmental impacts than competing products manufactured of concrete and P/C.展开更多
The study looked at the levels of polycyclic aromatic hydrocarbons (PAHs) in leachates from a solid waste disposal site and an effluent from an oil refinery in some water bodies around Accra. Sixteen (PAHs) were extra...The study looked at the levels of polycyclic aromatic hydrocarbons (PAHs) in leachates from a solid waste disposal site and an effluent from an oil refinery in some water bodies around Accra. Sixteen (PAHs) were extracted simultaneously by solid phase and analysis by gas chromatograph. The results of this study gener-ally demonstrated that there were elevated levels of PAHs in the water sample of the Densu River, Chemu, Korle and Kpeshi Lagoons. The average concentration of PAHs in the water ranged from 0.000 of many of the PAHs to 0.552µg/L, for Acenapththene to 11.399µg/L for Benzo (ghi) perylene of the Chemu Lagoon, 0.00µg/L for Benzo (a) Pyrene to 8.800µg/L for Benzo (ghi) perylene (Korle Lagoon) and 0.052µg/L for Pyrene to 4.703ug/L for Acenaphthylene of the Kpeshi Lagoon and 0.00µg/L for pyrene to Acenaphthylene 2.926µg/L of the Weija Dam. Concentrations ranging from below detection level to 14.587µg/L were also recorded at the Oblogo solid waste dump and it’s environ. The Weija dam supply over two million gallons of portable water daily to the people of Accra and the levels of the PAH determined is worrying, as a result, the Oblogoh disposal site ought to be re-located to avert any possible epidemic.展开更多
Environmental pollution can have detrimental effects on crop yield and its consumers. The current study was designed to investigate the potential human health risks associated with the consumption of lettuce crop cont...Environmental pollution can have detrimental effects on crop yield and its consumers. The current study was designed to investigate the potential human health risks associated with the consumption of lettuce crop contaminated with toxic heavy metals and microbiological status. Irrigated water, soil and lettuce were analyzed by AAS technics for heavy metals including Cd, Cr, Cu, Mn, Ni, Pb and Zn. Transfer factor (TF), daily intake of metals (DIM) and health risk index (HRI) were also calculated. Microbial analysis was carried out for the presence foodborne pathogens. The results showed that the heavy metals contents were higher in the soil than wastewater and the vegetables. Heavy metals ranged (mg·Kg-1) for Cd (1.27 to 2.93), Cr (7.28 to 7.38), Cu (0.91 to 1.70), Mn (0.29 to 6.60), Ni (1.74 to 2.16), Pb (1.32 to 1.69), Zn (3.08 to 3.79);and were higher than the WHO maximum limit permissible (ML) in vegetables. HRI TF values designated an enhanced bio-contamination. Microbial numeration revealed the presence of spoiler and pathogenic microorganisms. The lettuce tested was not safe for human use, especially for direct consumption by human beings.展开更多
Municipal solid waste open dump site operation is an important element of waste management in Nigeria, both today and in the future. Dump site fires are common occurrences in the study area. The contribution of?munici...Municipal solid waste open dump site operation is an important element of waste management in Nigeria, both today and in the future. Dump site fires are common occurrences in the study area. The contribution of?municipal solid waste dump site fires to atmospheric pollution in the Niger Delta, Nigeria has been assessed experimentally. Five (5) municipal solid waste dump sites where fire incidence is a frequent and regular occurrence were chosen for the study. At each of the identified municipal solid waste dump site, eight (8) air quality monitoring parameters, suspended particulate matter (SPM10), nitrogen dioxide (NO2), carbon dioxide (CO2), carbon monoxide (CO), sulphur dioxide (SO2), methane (CH4), ammonia (NH3) and Hydrogen sulphide (H2S) were determined using a series of hand held air quality monitoring equipment. Results indicate the levels of SPM ranged between 773 and 801 μg/m3 and the levels of CO ranged between 133.7 and 141.6 ppm. The levels of CO2 ranged between 401 ppm and 404.5 ppm while that of NO2 ranged between 21.0 ppm and 27.3 ppm. The levels of SO2 ranged between 27.7 ppm and 37.1 ppm while that of NH3 ranged from 14.7 to 19.5 ppm. The levels of methane in the study area ranged between 2310 ppm and 2771 ppm and within the?vicinity of dump site fires H2S concentration ranges from 3.4 to 7.7 ppm. Levels of SPM, CO, CO2, and CH4 within the vicinity of the dump site fires were above regulatory limits. Dump site fires in the study area could threaten the health of anyone especially the dump site workers that are regularly exposed to the thick smoke and can be implicated in climate change debate. There is a need to develop better practices with regard to municipal solid waste open dump site operation and emission control.展开更多
Biologically meaningful and cost-effective indicators are needed for assessing and monitoring the impacts of tropospheric ozone(0_(3)) on vegetation and are required in Europe by the National Emission Ceilings Directi...Biologically meaningful and cost-effective indicators are needed for assessing and monitoring the impacts of tropospheric ozone(0_(3)) on vegetation and are required in Europe by the National Emission Ceilings Directive(2016).However,a clear understanding on the best suited indicators is missing.The MOTTLES(MOnitoring ozone injury for seTTing new critical LEvelS) project set up a new generation network for 0_(3) monitoring in forest plots in order to:1) estimate the stomatal 0_(3) fluxes(Phytotoxic Ozone Dose above a threshold Y of uptake,PODY);and 2) collect visible foliar 0_(3) injury,both within the forest plot(ITP) and along the Light Exposed Sampling Site(LESS) along the forest edge.Nine forest sites at high 0_(3) risk were selected across Italy over 2017-2019 and significant correlations(p <0.05) were found between the percentage of symptomatic plant species within the LESS,and POD1(PODY,with Y=1 nmol 0_(3) m^(-2) s^(-1)) calculated for mixed forest species(r=0.53)and with the occurrence and severity of visible foliar 0_(3) injury on the dominant species in the plots(r=0.65).A generic flux-based critical level for mixed forest species was derived within the LESS and it was recommended using11 mmol m^(-2) POD1 as the critical level for forest protection against 0_(3) injury,similar to the critical level obtained in the ITP(12 mmol m^(-2) POD1).It was concluded that the frequency of symptomatic plant species within a LESS is a suitable and effective plant-response indicator of phytotoxic 0_(3) levels in forest monitoring.LESS is a non-destructive,less complex and less time-consuming approach compared to the ITP for monitoring foliar 0_(3) injury in the long term.Assessing visible foliar 0_(3) injury in the ITP might only underestimate the 0_(3) risk assessment at individual sites.These results are biologically meaningful and useful to monitoring experts and environmental policy makers.展开更多
Asset management is a strategic decision-making aspect of social infra-structure that ensures safety by predicting long-term conditions and maximizing effectiveness under budgetary constraints. Predicting the deterior...Asset management is a strategic decision-making aspect of social infra-structure that ensures safety by predicting long-term conditions and maximizing effectiveness under budgetary constraints. Predicting the deterioration of impervious walls is essential in the asset management of coastal landfill sites, particularly in the design of their maintenance and repair strategy. In this paper, a quantitative evaluation of the leakage of toxic substances in coastal landfill sites where deterioration of side impervious walls has decreased the water interception performance is reported. In addition, risk evaluation based on the asset management of the leakage is applied to determine an appropriate repair method. The strategy of repairing the walls when the concentration of the toxic substances leaking into the sea area exceeds the closure and abandonment of coastal landfill sites is demonstrated to be superior. Moreover, the strategy of repairing only the seaside side impervious wall is shown to be cost-effective.展开更多
With rising demand for clean energy,global focus turns to finding ideal sites for large-scale underground hydrogen storage(UHS)in depleted petroleum reservoirs.A thorough preliminary reservoir evaluation before hydrog...With rising demand for clean energy,global focus turns to finding ideal sites for large-scale underground hydrogen storage(UHS)in depleted petroleum reservoirs.A thorough preliminary reservoir evaluation before hydrogen(H_(2))injection is crucial for UHS success and safety.Recent criteria for UHS often emphasize economics and chemistry,neglecting key reservoir attributes.This study introduces a comprehensive framework for the reservoir-scale preliminary assessment,specifically tailored for long-term H_(2) storage within depleted gas reservoirs.The evaluation criteria encompass critical components,including reservoir geometry,petrophysical properties,tectonics,and formation fluids.To illustrate the practical application of this approach,we assess the Barnett shale play reservoir parameters.The assessment unfolds through three key stages:(1)A systematic evaluation of the reservoir's properties against our comprehensive screening criteria determines its suitability for H_(2) storage.(2)Using both homogeneous and multilayered gas reservoir models,we explore the feasibility and efficiency of H_(2) storage.This phase involves an in-depth examination of reservoir behavior during the injection stage.(3)To enhance understanding of UHS performance,sensitivity analyses investigate the impact of varying reservoir dimensions and injection/production pressures.The findings reveal the following:(a)Despite potential challenges associated with reservoir compaction and aquifer support,the reservoir exhibits substantial promise as an H_(2) storage site.(b)Notably,a pronounced increase in reservoir pressure manifests during the injection stage,particularly in homogeneous reservoirs.(c)Furthermore,optimizing injection-extraction cycle efficiency can be achieved by augmenting reservoir dimensions while maintaining a consistent thickness.To ensure a smooth transition to implementation,further comprehensive investigations are advised,including experimental and numerical studies to address injectivity concerns and explore storage site development.This evaluation framework is a valuable tool for assessing the potential of depleted gas reservoirs for large-scale hydrogen storage,advancing global eco-friendly energy systems.展开更多
基金Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB 42010203)the National Natural Science Foundation of China(No.42176090)。
文摘Scallop culture is an important way of bottom-seeding marine ranching,which is of great significance to improve the current situation of fishery resources.However,there are some problems in site-selection evaluation of marine ranching,such as imperfect criteria system,complex structure,untargeted criteria quantification,etc.In addition,no site-selection evaluation method of bottom-seeding culture areas for scallops is available.Therefore,we established a hierarchy structure model according to the analytic hierarchy process(AHP)theory,in which social,physical,chemical,and biological environments are used as main criteria,and marine functional zonation,water depth,current,water temperature,salinity,substrate type,water quality,sediment quality,red tide,phytoplankton,and zooplankton are used as sub-criteria,on which a multi-parameter evaluation system is set up.Meanwhile,the dualism method,assignment method,and membership function method were used to quantify sub-criteria,and a quantitative evaluation for the entire criteria was added,including the evaluation and analysis of two types of unsuitable environmental situations.By overall consideration in scallop yield,quality,and marine ranching construction objectives,the weight of the main criteria could be determined.Five grades in the suitability corresponding to the evaluation result were divided,and the Python language was used to create an evaluation system for efficient calculation and intuitive presentation of the evaluation outcome.Eight marine cases were simulated based on existing survey data,and the results prove that the method is feasible for evaluating and analyzing the site selection of bottom-seeding culture areas for scallops under various environmental situations.The proposed evaluation method can be promoted for the site selection of bottom-seeding marine ranching.This study provided theoretical and methodological references for the site selection evaluation of other types of marine ranching.
基金financially supported from the National Key Research and Development Program of China(No.2019YFC1803601)the Fundamental Research Funds for the Central Universities of Central South University,China(No.2023ZZTS0801)+1 种基金the Postgraduate Innovative Project of Central South University,China(No.2023XQLH068)the Postgraduate Scientific Research Innovation Project of Hunan Province,China(No.QL20230054)。
文摘A general prediction model for seven heavy metals was established using the heavy metal contents of 207soil samples measured by a portable X-ray fluorescence spectrometer(XRF)and six environmental factors as model correction coefficients.The eXtreme Gradient Boosting(XGBoost)model was used to fit the relationship between the content of heavy metals and environment characteristics to evaluate the soil ecological risk of the smelting site.The results demonstrated that the generalized prediction model developed for Pb,Cd,and As was highly accurate with fitted coefficients(R^(2))values of 0.911,0.950,and 0.835,respectively.Topsoil presented the highest ecological risk,and there existed high potential ecological risk at some positions with different depths due to high mobility of Cd.Generally,the application of machine learning significantly increased the accuracy of pXRF measurements,and identified key environmental factors.The adapted potential ecological risk assessment emphasized the need to focus on Pb,Cd,and As in future site remediation efforts.
文摘Groundwater vulnerability assessment is a crucial step in the efficient management of groundwater resources,especially in areas with intensive anthropogenic activities and groundwater pollution.In the present study,the DRASTIC method was applied using Geographic Information System(GIS)to delineate groundwater vulnerability zones in the Erbil Dumpsite area,Central Erbil Basin,North Iraq.Results showed that the area was classified into four vulnerability classes:Very low(16.97%),low(27.67%),moderate(36.55%)and high(18.81%).The southern,south-eastern and northern parts of the study area exhibited the highest vulnerability potential,while the central-northern,northern and north-western regions displayed the lowest vulnerability potential.Moreover,results of the single-parameter sensitivity analysis indicated that amongst the seven DRASTIC parameters,the unsaturated zone and the aquifer media were the most influencing parameters.In conclustion,the correlation of 25 nitrate concentration values with the final vulnerability map,assessed using the Pearson correlation coefficient,yielded a satisfactory result of R=0.72.
基金implemented in the frames of a theme "Studying geochemical stream of elements in atmospheric air of Yerevan"(No 13-1E220,2011) under agreement-based(thematic) financial support of the State Committee of Science to the Ministry of Education and Sciences RA
文摘The total concentrations of Cd,As,Pb,Cr,Ni,Co,Zn,Cu,Ag,Hg,and Mo were determined in the atmospheric dust of the city of Yerevan by atomic absorption spectrometry(AAnalyst PE 800).Heavy metal pollution levels were evaluated by calculating geo-accumulation(I_(geo)) and summary pollution(Z_c) indices.Potential human health risk was assessed using the United States Environmental Protection agency's human health risk assessment model.The results show that mean contents of all elements tested except Ni and Cr were substantially higher than local geochemical background values.According to the I_(geo),Yerevan territory is strongly-to-extremely polluted by As,Ag,Hg,Mo,and Cd.The Z_c assessment indicated that very high pollution was detected in 36%of samples,high in 32%,average in 12%,and low in 20%.The health risk assessment revealed a noncarcinogenic risk(HI >1) for children at 13 samplings sites and for adults at one sampling site.For children the risk was due to elevated levels of Mo,Cd,Co,and As,while for adults,only Mo.Carcinogenic risk(>1:1,000,000) of As and Cr via ingestion pathway was observed in 25 and 14 samples,respectively.This study,therefore,is the base for further detailed investigations to organize problematic site remediation and risk reduction measures.
文摘The seismic behavior of skewed bridges has not been well studied compared to straight bridges. Skewed bridges have shown extensive damage, especially due to deck rotation, shear keys failure, abutment unseating and column- bent drift. This research, therefore, aims to study the behavior of skewed and straight highway overpass bridges both with and without taking into account the effects of Soil-Structure Interaction (SSI) due to near-fault ground motions. Due to several sources of uncertainty associated with the ground motions, soil and structure, a probabilistic approach is needed. Thus, a probabilistic methodology similar to the one developed by the Pacific Earthquake Engineering Research Center (PEER) has been utilized to assess the probability of damage due to various levels of shaking using appropriate intensity measures with minimum dispersions. The probabilistic analyses were performed for various bridge configurations and site conditions, including sand ranging from loose to dense and clay ranging from soft to stiff, in order to evaluate the effects. The results proved a considerable susceptibility of skewed bridges to deck rotation and shear keys displacement. It was also found that SSI had a decreasing effect on the damage probability for various demands compared to the fixed-base model without including SSI. However, deck rotation for all types of the soil and also abutment unseating for very loose sand and soft clay showed an increase in damage probability compared to the fixed-base model. The damage probability for various demands has also been found to decrease with an increase of soil strength for both sandy and clayey sites. With respect to the variations in the skew angle, an increase in skew angle has had an increasing effect on the amplitude of the seismic response for various demands. Deck rotation has been very sensitive to the increase in the skew angle; therefore, as the skew angle increased, the deck rotation responded accordingly. Furthermore, abutment unseating showed an increasing trend due to an increase in skew angle for both fixed-base and SSI models.
基金Under the auspices of the National Key Research and Development Program of China (No. 2020YFC1521903)National Key Research and Development Program of China (No. 2018YFD1100104)。
文摘Ecological risk assessment(ERA) is an indispensable method for systematic monitoring of World Heritage Sites(WHSs) exposed to various anthropogenic factors and natural disasters. Remote sensing(RS) and geographical information systems(GIS) can eliminate many limitations in traditional ERA methods. In this study, changes in ecological risk at Huangshan Mountain, the first mixed WHS in China, over the period of 1984–2019 were explored using remote sensing images and products by considering both natural disasters and human disturbance. Results show that of the four land cover types in Huangshan Mountain, namely water, forest, building and farmland, the main land cover type is forest. During the 35 yr, lands categorised at low or relatively low ecological risk levels are dominant in Huangshan Mountain, with the lowest and highest ERIs(ecological risk index) in 1990 and 2010, respectively. The areas at the five ecological risk levels have declined as follows: relatively low > low > medium > relatively high > high. Changes in ecological risks are closely related to changes in land cover and natural disasters. Even though major natural disasters may affect the ecological risk level in the whole region, changes in land cover caused by human activities will shift the ecological risk level in some areas. Our attempts can be modified and applied to other sites, and offer policy implications for protection and preservation of WHSs.
基金financially supported by the Marine Renewable Energy Research Project of State Oceanic Administration of China(Grant No.GHME2013GC03)
文摘A damage assessment methodology based on the Hashin failure theory for glass fiber reinforced polymer(GFRP)composite blade is proposed. The typical failure mechanisms including the fiber tension/compression and matrix tension/compression are considered to describe the damage behaviors. To give the flapwise and edgewise loading along the blade span, the Blade Element Momentum Theory(BEMT) is adopted. In conjunction with the hydrodynamic analysis, the structural analysis of the composite blade is cooperatively performed with the Hashin damage model. The damage characteristics of the composite blade, under normal and extreme operational conditions,are comparatively analyzed. Numerical results demonstrate that the matrix tension damage is the most significant failure mode which occurs in the mid-span of the blade. The blade internal configurations including the box-beam, Ibeam, left-C beam and right-C beam are compared and analyzed. The GFRP and carbon fiber reinforced polymer(CFRP) are considered and combined. Numerical results show that the I-beam is the best structural type. The structural performance of composite tidal turbine blades could be improved by combining the GFRP and CFRP structure considering the damage and cost-effectiveness synthetically.
基金supported jointly by the National Basic Research Program of China(″973″Program)(No.2014CB046200)the Natural Science Foundation of Jiangsu Province(No.BK2014059)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe National Natural Science Foundation of China(No.11172135)
文摘Fatigue strength assessment of a horizontal axis wind turbine(HAWT)composite blade is considered.Fatigue load cases are identified,and loads are calculated by the GH Bladed software which is specified at the IEC61400 international specification and GL(Germanisher Lloyd)regulations for the wind energy conversion system.Stress analysis is performed with a 3-D finite element method(FEM).Considering Saint-Venant′s principle,a uniform cross section FEM model is built at each critical zone.Stress transformation matrixes(STM)are set up by applied six unit load components on the FEM model separately.STM can be used to convert the external load into stresses in the linear elastic range.The main material of composite wind turbine blade is fiber reinforced plastics(FRP).In order to evaluate the degree of fatigue damage of FRP,the stresses of fiber direction are extracted and the well-known strength criterion-Puck theory is used.The total fatigue damage of each laminate on the critical point is counted by the rain-flow counting method and Miner′s damage law based on general S-N curves.Several sections of a 45.3mblade of a 2 MW wind turbine are studied using the fatigue evaluation method.The performance of this method is compared with far more costly business software FOCUS.The results show that the fatigue damage of multi-axis FRP can be assessed conveniently by the FEM-STM method.And the proposed method gives a reliable and efficient method to analyze the fatigue damage of slender composite structure with variable cross-sections.
基金supported by the National Science Foundation of China (Grant No. 41790432) the International partnership program of CAS (Grant No. 131551KYSB20160002)
文摘On August 8, 2017, a Ms = 7.0 magnitude earthquake occurred in the Jiuzhaigou Valley, in Sichuan Province, China(N: 33.20°, E: 103.82°). Jiuzhaigou Valley is an area recognized and listed as a world heritage site by UNESCO in 1992. Data analysis and field survey were conducted on the landslide, collapse, and debris flow gully, to assess the coseismic geological hazards generated by the earthquake using an unmanned aerial vehicle(UAV), remote-sensing imaging, laser range finders, geological radars, and cameras. The results highlighted the occurrence of 13 landslides, 70 collapses, and 25 potential debris flow gullies following the earthquake. The hazards were classified on the basis of their size and the potential property loss attributable to them. Consequently, 14 large-scale hazards, 30 medium-sized hazards, and 64 small hazards accounting for 13%, 28%, and 59% of the total hazards, respectively, were identified. Based on the variation tendency of the geological hazards that ensued in areas affected by the Kanto earthquake(Japan), Chi-chi earthquake(Taiwan China), and Wenchuan earthquake(Sichuan China), the study predicts that, depending on the rain intensity cycle, the duration of geological hazard activities in the Jiuzhaigou Valley may last over ten years and will gradually decrease for the following five to ten yearsbefore returning to pre-earthquake levels. Thus,necessary monitoring and early warning systems must be implemented to ensure the safety of residents,workers and tourists during the construction of engineering projects and reopening of scenic sites to the public.
文摘This paper presents spatial variation of seismic hazard at the surface level for India,covering 6-38°N and 68-98°E.The most recent knowledge on seismic activity in the region has been used to evaluate the hazard incorporating uncertainties associated with the seismicity parameters using different modeling methodologies.Three types of seismic source models,viz.linear sources,gridded seismicity model and areal sources,were considered to model the seismic sources and different sets of ground motion prediction equations were used for different tectonic provinces to characterize the attenuation properties.The hazard estimation at bedrock level has been carried out using probabilistic approach and the results obtained from various methodologies were combined in a logic tree framework.The seismic site characterization of India was done using topographic slope map derived from Digital Elevation Model data.This paper presents estimation of the hazard at surface level,using appropriate site amplification factors corresponding to various site classes based on V_(S30) values derived from the topographic gradient.Spatial variation of surface level peak horizontal acceleration(PHA) for return periods of 475 years and 2475 years are presented as contour maps.
基金supported by the Changsha Municipal Natural Science Foundation,China,(No.kq2202233)the Science and Technology Program of Guangdong Forestry Administration,China(No.2020-KYXM-08)+2 种基金the Major Science and Technology Program for Water Pollution Control and Treatment,China(No.2017ZX07101003)the National Key Research and Development Project of China(No.2019YFC1804800)the Pearl River S&T Nova Program of Guangzhou,China(No.201710010065)。
文摘Limited information is available on long-term effects of metal(loid)s pollution incidents. Here, we analyze the distribution characteristics and quantification of elements in the Southwest China Keda mining site, which is one of the most populated sites and enables human health and ecological risk assessments of elemental pollution. The results on modified degree of contamination indicated that the soil and sediment were highly contaminated near Dahu Lake.The health risk of children was almost 2.5 times that of adults in surface water, and 7.1 times in soil, respectively.Moreover, Tl and As were the main health risk contributors in surface water and soil, respectively, and As posed the highest ecological risk both in soil and sediment. These results indicated the potential impact of toxic metal(loid)s on the health of residents and environment. Hence, more scientific attention and proper management need to be paid to this environmental challenge in the future.
基金Under the auspices of National Natural Science Foundation of China(No.41130526)Beijing Municipal Natural Science Foundation(No.8122020)
文摘Farmland protection and delimitation in the urban fringe considers not only natural factors but also the spatial characters and site factors. Taking Daxing District, Beijing in China as a case study, this paper used landscape ecology and power-law methods to ana- lyze and evaluate farmland loss during the period of 2004~2007 based on the interpretation results of SPOT5 remote sensing images in 2004 and 2007. At the patch level, we selected four landscape indices, namely patch size, shape index, the nearest neighbor distance between farmland and construction land (including residential land and other construction land), and cropping type, to evaluate the risk of farmland loss and establish a farmland site analysis indicator system. The results showed that patch size and shape index have a sig- nificant positive correlation with farmland loss, whereas the distance to construction land has a clear negative correlation with farmland loss. As regards cropping type, fallow farmland is much easier for non-agriculUlral use than cultivated farmland. The relative transition ratio among vegetable land, fallow farmland and cultivated farmland is 1 : 5.6 : 1. The patch size of lost farmland follows a power-law distribution, indicating that not only small parcels but also large parcels can be lost. Patch size less than 4 ha or more than 15 ha is in high loss risk, between 4 ha and 10 ha in medium loss risk, and larger than 10 ha and less than 15 ha in low risk. Farmland with a more regular shape has a higher likelihood of loss. Patch shape index less than 2.0 is in high loss risk, between 2.0 and 3.0 in medium loss risk, and larger than 3.0 in low risk. Construction land has a varying impact on farmland loss, the residential land effeeted distance is 1000 m, and that of the other construction land is 2000 m. This analysis showed the relationships between site factors and farmland loss, and the analysis framework can provide support and reference for farmland protection and delimitation of prime farmland in China.
文摘Creosote-treated wooden railroad crossties have been used for more than a century to support steel rails and to transfer load from the rails to the underlying ballast while keeping the rails at the correct gauge. As transportation engineers look for improved service life and environmental performance in railway systems, alternatives to the creosote-treated wooden crosstie are being considered. This paper compares the cradle-to-grave environmental life cycle assessment (LCA) results of creosote-treated wooden railroad crossties with the primary alternative products: concrete and plastic composite (P/C) crossties. This LCA includes a life cycle inventory (LCI) to catalogue the input and output data from crosstie manufacture, service life, and disposition, and a life cycle impact assessment (LCIA) to evaluate greenhouse gas (GHG) emissions, fossil fuel and water use, and emissions with the potential to cause acidification, smog, ecotoxicity, and eutrophication. Comparisons of the products are made at a functional unit of 1.61 kilometers (1.0 mile) of rail-road track per year. This LCA finds that the manufacture, use, and disposition of creosote-treated wooden railroad crossties offers lower fossil fuel and water use and lesser environmental impacts than competing products manufactured of concrete and P/C.
文摘The study looked at the levels of polycyclic aromatic hydrocarbons (PAHs) in leachates from a solid waste disposal site and an effluent from an oil refinery in some water bodies around Accra. Sixteen (PAHs) were extracted simultaneously by solid phase and analysis by gas chromatograph. The results of this study gener-ally demonstrated that there were elevated levels of PAHs in the water sample of the Densu River, Chemu, Korle and Kpeshi Lagoons. The average concentration of PAHs in the water ranged from 0.000 of many of the PAHs to 0.552µg/L, for Acenapththene to 11.399µg/L for Benzo (ghi) perylene of the Chemu Lagoon, 0.00µg/L for Benzo (a) Pyrene to 8.800µg/L for Benzo (ghi) perylene (Korle Lagoon) and 0.052µg/L for Pyrene to 4.703ug/L for Acenaphthylene of the Kpeshi Lagoon and 0.00µg/L for pyrene to Acenaphthylene 2.926µg/L of the Weija Dam. Concentrations ranging from below detection level to 14.587µg/L were also recorded at the Oblogo solid waste dump and it’s environ. The Weija dam supply over two million gallons of portable water daily to the people of Accra and the levels of the PAH determined is worrying, as a result, the Oblogoh disposal site ought to be re-located to avert any possible epidemic.
文摘Environmental pollution can have detrimental effects on crop yield and its consumers. The current study was designed to investigate the potential human health risks associated with the consumption of lettuce crop contaminated with toxic heavy metals and microbiological status. Irrigated water, soil and lettuce were analyzed by AAS technics for heavy metals including Cd, Cr, Cu, Mn, Ni, Pb and Zn. Transfer factor (TF), daily intake of metals (DIM) and health risk index (HRI) were also calculated. Microbial analysis was carried out for the presence foodborne pathogens. The results showed that the heavy metals contents were higher in the soil than wastewater and the vegetables. Heavy metals ranged (mg·Kg-1) for Cd (1.27 to 2.93), Cr (7.28 to 7.38), Cu (0.91 to 1.70), Mn (0.29 to 6.60), Ni (1.74 to 2.16), Pb (1.32 to 1.69), Zn (3.08 to 3.79);and were higher than the WHO maximum limit permissible (ML) in vegetables. HRI TF values designated an enhanced bio-contamination. Microbial numeration revealed the presence of spoiler and pathogenic microorganisms. The lettuce tested was not safe for human use, especially for direct consumption by human beings.
文摘Municipal solid waste open dump site operation is an important element of waste management in Nigeria, both today and in the future. Dump site fires are common occurrences in the study area. The contribution of?municipal solid waste dump site fires to atmospheric pollution in the Niger Delta, Nigeria has been assessed experimentally. Five (5) municipal solid waste dump sites where fire incidence is a frequent and regular occurrence were chosen for the study. At each of the identified municipal solid waste dump site, eight (8) air quality monitoring parameters, suspended particulate matter (SPM10), nitrogen dioxide (NO2), carbon dioxide (CO2), carbon monoxide (CO), sulphur dioxide (SO2), methane (CH4), ammonia (NH3) and Hydrogen sulphide (H2S) were determined using a series of hand held air quality monitoring equipment. Results indicate the levels of SPM ranged between 773 and 801 μg/m3 and the levels of CO ranged between 133.7 and 141.6 ppm. The levels of CO2 ranged between 401 ppm and 404.5 ppm while that of NO2 ranged between 21.0 ppm and 27.3 ppm. The levels of SO2 ranged between 27.7 ppm and 37.1 ppm while that of NH3 ranged from 14.7 to 19.5 ppm. The levels of methane in the study area ranged between 2310 ppm and 2771 ppm and within the?vicinity of dump site fires H2S concentration ranges from 3.4 to 7.7 ppm. Levels of SPM, CO, CO2, and CH4 within the vicinity of the dump site fires were above regulatory limits. Dump site fires in the study area could threaten the health of anyone especially the dump site workers that are regularly exposed to the thick smoke and can be implicated in climate change debate. There is a need to develop better practices with regard to municipal solid waste open dump site operation and emission control.
基金carried out with the contribution of the LIFE financial instrument of the European Union in the framework of the MOTTLES project "Monitoring ozone injury for setting new critical levels" (LIFE15 ENV/IT/000183)。
文摘Biologically meaningful and cost-effective indicators are needed for assessing and monitoring the impacts of tropospheric ozone(0_(3)) on vegetation and are required in Europe by the National Emission Ceilings Directive(2016).However,a clear understanding on the best suited indicators is missing.The MOTTLES(MOnitoring ozone injury for seTTing new critical LEvelS) project set up a new generation network for 0_(3) monitoring in forest plots in order to:1) estimate the stomatal 0_(3) fluxes(Phytotoxic Ozone Dose above a threshold Y of uptake,PODY);and 2) collect visible foliar 0_(3) injury,both within the forest plot(ITP) and along the Light Exposed Sampling Site(LESS) along the forest edge.Nine forest sites at high 0_(3) risk were selected across Italy over 2017-2019 and significant correlations(p <0.05) were found between the percentage of symptomatic plant species within the LESS,and POD1(PODY,with Y=1 nmol 0_(3) m^(-2) s^(-1)) calculated for mixed forest species(r=0.53)and with the occurrence and severity of visible foliar 0_(3) injury on the dominant species in the plots(r=0.65).A generic flux-based critical level for mixed forest species was derived within the LESS and it was recommended using11 mmol m^(-2) POD1 as the critical level for forest protection against 0_(3) injury,similar to the critical level obtained in the ITP(12 mmol m^(-2) POD1).It was concluded that the frequency of symptomatic plant species within a LESS is a suitable and effective plant-response indicator of phytotoxic 0_(3) levels in forest monitoring.LESS is a non-destructive,less complex and less time-consuming approach compared to the ITP for monitoring foliar 0_(3) injury in the long term.Assessing visible foliar 0_(3) injury in the ITP might only underestimate the 0_(3) risk assessment at individual sites.These results are biologically meaningful and useful to monitoring experts and environmental policy makers.
文摘Asset management is a strategic decision-making aspect of social infra-structure that ensures safety by predicting long-term conditions and maximizing effectiveness under budgetary constraints. Predicting the deterioration of impervious walls is essential in the asset management of coastal landfill sites, particularly in the design of their maintenance and repair strategy. In this paper, a quantitative evaluation of the leakage of toxic substances in coastal landfill sites where deterioration of side impervious walls has decreased the water interception performance is reported. In addition, risk evaluation based on the asset management of the leakage is applied to determine an appropriate repair method. The strategy of repairing the walls when the concentration of the toxic substances leaking into the sea area exceeds the closure and abandonment of coastal landfill sites is demonstrated to be superior. Moreover, the strategy of repairing only the seaside side impervious wall is shown to be cost-effective.
文摘With rising demand for clean energy,global focus turns to finding ideal sites for large-scale underground hydrogen storage(UHS)in depleted petroleum reservoirs.A thorough preliminary reservoir evaluation before hydrogen(H_(2))injection is crucial for UHS success and safety.Recent criteria for UHS often emphasize economics and chemistry,neglecting key reservoir attributes.This study introduces a comprehensive framework for the reservoir-scale preliminary assessment,specifically tailored for long-term H_(2) storage within depleted gas reservoirs.The evaluation criteria encompass critical components,including reservoir geometry,petrophysical properties,tectonics,and formation fluids.To illustrate the practical application of this approach,we assess the Barnett shale play reservoir parameters.The assessment unfolds through three key stages:(1)A systematic evaluation of the reservoir's properties against our comprehensive screening criteria determines its suitability for H_(2) storage.(2)Using both homogeneous and multilayered gas reservoir models,we explore the feasibility and efficiency of H_(2) storage.This phase involves an in-depth examination of reservoir behavior during the injection stage.(3)To enhance understanding of UHS performance,sensitivity analyses investigate the impact of varying reservoir dimensions and injection/production pressures.The findings reveal the following:(a)Despite potential challenges associated with reservoir compaction and aquifer support,the reservoir exhibits substantial promise as an H_(2) storage site.(b)Notably,a pronounced increase in reservoir pressure manifests during the injection stage,particularly in homogeneous reservoirs.(c)Furthermore,optimizing injection-extraction cycle efficiency can be achieved by augmenting reservoir dimensions while maintaining a consistent thickness.To ensure a smooth transition to implementation,further comprehensive investigations are advised,including experimental and numerical studies to address injectivity concerns and explore storage site development.This evaluation framework is a valuable tool for assessing the potential of depleted gas reservoirs for large-scale hydrogen storage,advancing global eco-friendly energy systems.