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Disinfection Byproducts and Their Precursors in Drinking Water Sources:Origins,Influencing Factors,and Environmental Insights
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作者 Rong Xiao Yang Deng +1 位作者 Zuxin Xu Wenhai Chu 《Engineering》 SCIE EI CAS CSCD 2024年第5期36-50,共15页
Tracing the contamination origins in water sources and identifying the impacts of natural and human processes are essential for ecological safety and public health.However,current analysis approaches are not ideal,as ... Tracing the contamination origins in water sources and identifying the impacts of natural and human processes are essential for ecological safety and public health.However,current analysis approaches are not ideal,as they tend to be laborious,time-consuming,or technically difficult.Disinfection byproducts(DBPs)are a family of well-known secondary pollutants formed by the reactions of chemical disinfectants with DBP precursors during water disinfection treatment.Since DBP precursors have various origins(e.g.,natural,domestic,industrial,and agricultural sources),and since the formation of DBPs from different precursors in the presence of specific disinfectants is distinctive,we argue that DBPs and DBP precursors can serve as alternative indicators to assess the contamination in water sources and identify pollution origins.After providing a retrospective of the origins of DBPs and DBP precursors,as well as the specific formation patterns of DBPs from different precursors,this article presents an overview of the impacts of various natural and anthropogenic factors on DBPs and DBP precursors in drinking water sources.In practice,the DBPs(i.e.,their concentration and speciation)originally present in source water and the DBP precursors determined using DBP formation potential tests—in which water samples are dosed with a stoichiometric excess of specific disinfectants in order to maximize DBP formation under certain reaction conditions—can be considered as alternative metrics.When jointly used with other water quality parameters(e.g.,dissolved organic carbon,dissolved organic nitrogen,fluorescence,and molecular weight distribution)and specific contaminants of emerging concern(e.g.,certain pharmaceuticals and personal care products),DBPs and DBP precursors in drinking water sources can provide a more comprehensive picture of water pollution for better managing water resources and ensuring human health. 展开更多
关键词 Disinfection byproducts Disinfection byproduct precursors Drinking water sources Contamination indicator natural factors Human factors
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Prospective study of hepatitis B and D epidemiology and risk factors in Romania:A 10-year update
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作者 Speranta Iacob Liana Gheorghe +11 位作者 Mirela Onica Laura Huiban Corina Silvia Pop Ciprian Brisc Roxana Sirli Carmen Ester Cristina Mihaela Brisc Sorina Diaconu Ion Rogoveanu Larisa Sandulescu Deiana Vuletici Anca Trifan 《World Journal of Hepatology》 2024年第4期640-649,共10页
BACKGROUND The global burden of hepatitis D virus(HDV)infection represents a major medical challenge and a public health crisis worldwide.However,there is a lack of accurate data on the epidemiology and risk factors f... BACKGROUND The global burden of hepatitis D virus(HDV)infection represents a major medical challenge and a public health crisis worldwide.However,there is a lack of accurate data on the epidemiology and risk factors for HDV.Hepatitis B virus(HBV)and HDV coinfection causes the most severe form of viral hepatitis,leading to a higher cumulative incidence of liver-related events compared with HBV monoinfection,including the need for liver transplantation and death.AIM To investigate the epidemiology,natural history,risk factors and clinical management of HBV and HDV coinfection in Romanian patients.METHODS This prospective study was conducted between January and July 2022 in six tertiary gastroenterology and hepatology referral centres in Romania.All consecutive adults admitted for any gastroenterology diagnosis who were HBV-positive were enrolled.Patients with acute hepatitis or incomplete data were excluded.Of the 25390 individuals who presented with any type of gastroenterology diagnosis during the study period,963 met the inclusion criteria.Testing for anti-HDV antibodies and HDV RNA was performed for all participants.Demographic and risk factor data were collected by investigators using medical charts and patient questionnaires.All data were stored in an anonymized online database during the study.RESULTS The prevalence of HBV was 3.8%;among these patients,the prevalence of HBV/HDV coinfection was 33.1%.The median age of the study population was 54.0 years,and it consisted of 55.1%men.A higher prevalence of HBV/HDV coinfection was observed in patients 50–69 years old.Patients with HBV/HDV coinfection were significantly older than those with HBV monoinfection(P=0.03).Multivariate multiple regression analysis identified female gender(P=0.0006),imprisonment(P<0.0001),older age at diagnosis(P=0.01)and sexual contact with persons with known viral hepatitis(P=0.0003)as significant risk factors for HDV.CONCLUSION This study shows that HDV infection among those with HBV remains endemic in Romania and updates our understanding of HDV epidemiology and associated risk factors.It emphasizes the need for systematic screening for HDV infection and collaborative initiatives for controlling and preventing HBV and HDV infection. 展开更多
关键词 EPIDEMIOLOGY Hepatitis B Hepatitis D natural history Risk factors Romania
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Unveiling significant risk factors for intensive care unit-acquired weakness:Advancing preventive care
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作者 Chun-Yao Cheng Wen-Rui Hao Tzu-Hurng Cheng 《World Journal of Clinical Cases》 SCIE 2024年第18期3288-3290,共3页
In this editorial,we discuss an article titled,“Significant risk factors for intensive care unit-acquired weakness:A processing strategy based on repeated machine learning,”published in a recent issue of the World J... In this editorial,we discuss an article titled,“Significant risk factors for intensive care unit-acquired weakness:A processing strategy based on repeated machine learning,”published in a recent issue of the World Journal of Clinical Cases.Intensive care unit-acquired weakness(ICU-AW)is a debilitating condition that affects critically ill patients,with significant implications for patient outcomes and their quality of life.This study explored the use of artificial intelligence and machine learning techniques to predict ICU-AW occurrence and identify key risk factors.Data from a cohort of 1063 adult intensive care unit(ICU)patients were analyzed,with a particular emphasis on variables such as duration of ICU stay,duration of mechanical ventilation,doses of sedatives and vasopressors,and underlying comorbidities.A multilayer perceptron neural network model was developed,which exhibited a remarkable impressive prediction accuracy of 86.2%on the training set and 85.5%on the test set.The study highlights the importance of early prediction and intervention in mitigating ICU-AW risk and improving patient outcomes. 展开更多
关键词 Intensive care unit-acquired weakness artificial intelligence Machine learning Neural network Risk factors Prediction Critical care
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Spatiotemporal Characteristics of Typical Ecosystem Services and Their Spatial Responses to Driving Factors in Ecologically Fragile Areas in Upper Yellow River,China
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作者 LIANG Gui FANG Fengman +1 位作者 LIN Yuesheng ZHANG Zhiming 《Chinese Geographical Science》 SCIE CSCD 2024年第4期674-688,共15页
The identification of dominant driving factors for different ecosystem services(ESs)is crucial for ecological conservation and sustainable development.However,the spatial heterogeneity of the dominant driving factors ... The identification of dominant driving factors for different ecosystem services(ESs)is crucial for ecological conservation and sustainable development.However,the spatial heterogeneity of the dominant driving factors affecting various ESs has not been adequately elucidated,particularly in ecologically fragile regions.This study employed the integrated valuation of ESs and trade-offs(InVEST)model to evaluate four ESs,namely,water yield(WY),soil conservation(SC),habitat quality(HQ),and carbon storage(CS),and then to identify the dominant driving factors of spatiotemporal differentiation of ES and further to characterize the spatial heterogeneity characteristics of the dominant driving factors in the eco-fragile areas of the upper Yellow River,China from 2000 to 2020.The results demonstrated that WY exhibited northeast-high and northwest-low patterns in the upper Yellow River region,while high values of SC and CS were distributed in central forested areas and a high value of HQ was distributed in vast grassland areas.The CS,WY,and SC exhibited decreasing trends over time.The most critical factors affecting WY,SC,HQ,and CS were the actual evapotranspiration,precipitation,slope,and normalized difference vegetation index,respectively.In addition,the effects of different factors on various ESs exhibited spatial heterogeneity.These results could provide spatial decision support for eco-protection and rehabilitation in ecologically fragile areas. 展开更多
关键词 integrated valuation of ecosystem services and trade-offs(InVEST)model geographically weighted regression(GWR) natural factor spatial heterogeneity Lanxi urban agglomeration upper Yellow River China
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Correlation Analysis between the Evapotranspiration Quantity and Climatic Factors of Artificial Grassland in Three River Sources Areas 被引量:11
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作者 冯承彬 张耀生 +2 位作者 赵双喜 赵新全 米兆荣 《Agricultural Science & Technology》 CAS 2008年第5期13-18,共6页
Based on observation data from the mini-type automatic weather station,the evapotranspiration quantity of reference crops from artificial grassland in three river sources areas was estimated by the method of FAO Penma... Based on observation data from the mini-type automatic weather station,the evapotranspiration quantity of reference crops from artificial grassland in three river sources areas was estimated by the method of FAO Penman-Monteith.The actual evapotranspiration quantity of grassland was calculated according to the synthetic crop coefficients referenced by FAQ-56,and the change of the actual evapotranspiration quantity of artificial grassland in three river sources areas as well as the relationship between the evapotranspiration quantity and climatic factors were studied.The results suggested that the seasonal change of actual evapotranspiration quantity in grassland was expressed in a single peak curve with the peak in the middle August,and daily transpiration quantity in summer was significantly larger than that in winter.The evapotranspiration was significantly correlated with air temperature,solar radiation and relative humidity,but not significantly correlated with wind speed.Effects of climatic factors on the evapotranspiration quantity of artificial grassland were ordered as follow:air temperature(T)>solar radiation(Ra)>relative humidity(RH)>wind speed(u2). 展开更多
关键词 THREE RIVER SOURCES artificial GRASSLAND EVAPOTRANSPIRATION CLIMATIC factor
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Quantitative Analysis of Natural and Human Factors of Oasis Change in the Tail of Shiyang River over the Past 60 Years 被引量:2
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作者 CHEN Yong YANG Guojing +2 位作者 ZHOU Lihua LIAO Jie WEI Xuan 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2020年第3期637-645,共9页
The human and natural factors complicit in the driving forces of oasis change have always received considerable interest from the international research community. In this study, we used principal component analysis o... The human and natural factors complicit in the driving forces of oasis change have always received considerable interest from the international research community. In this study, we used principal component analysis of natural and socio-economic statistical factors to quantitatively analyze the causal relationships and their contributions to the observed periodic expansion or shrinkage of the Minqin Oasis over almost 60 years. Our results show that human factors were the dominant factors governing expansion or shrinkage, with average contributions of 69.38% and 76.16%, respectively. Moreover, policy decisions have been the pivotal human factors. Under the influence of various policies, we have found that water resource utilization, land reclamation, population explosion, ecological protection and economic development have each played leading roles in different periods. This study provides a scientific basis for modelling the dynamics of an oasis for sustainable management. 展开更多
关键词 Oasis change natural factors human factors Minqin Oasis
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Optimization of causative factors using logistic regression and artificial neural network models for landslide susceptibility assessment in Ujung Loe Watershed, South Sulawesi Indonesia 被引量:11
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作者 Andang Suryana SOMA Tetsuya KUBOTA Hideaki MIZUNO 《Journal of Mountain Science》 SCIE CSCD 2019年第2期383-401,共19页
Landslide susceptibility maps(LSMs) play a vital role in assisting land use planning and risk mitigation. This study aims to optimize causative factors using logistic regression(LR) and an artificial neural network(AN... Landslide susceptibility maps(LSMs) play a vital role in assisting land use planning and risk mitigation. This study aims to optimize causative factors using logistic regression(LR) and an artificial neural network(ANN) to produce a LSM. The LSM is produced with 11 causative factors and then optimized using forward-stepwise LR(FSLR), ANN, and their combination(FSLR-ANN) until eight causative factors were found for each method. The ANN method produced superior validation results compared with LR. The ROC values for the training data set ranges between 0.8 and 0.9. On the other hand, validation with the percentage of landslide fall into LSM class high and very high, ANN method was higher(92.59%) than LR(82.12%). FSLR-ANN with nine causative factors gave the best validation results with respect to area under curve(AUC) values, and validation with the percentage of landslide fall into LSM class high and very high. In conclusion, ANN was found to be better than LR when producing LSMs. The best Optimization was combination of FSLR-ANN with nine causative factors and AUC success rate 0.847, predictive rate 0.844 and validation with landslide fall into high and very high class with 91.30%. It is an encouraging preliminary model towards a systematic introduction of FSLR-ANN model for optimization causative factors in landslide susceptibility assessment in the mountainous area of Ujung Loe Watershed. 展开更多
关键词 Optimized CAUSATIVE factor Landslide LOGISTIC Regression artificial neural network Indonesia
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A statistical analysis of spatiotemporal variations and determinant factors of forest carbon storage under China's Natural Forest Protection Program 被引量:9
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作者 Shengnan Wu Jiaqi Li +5 位作者 Wangming Zhou Bernard Joseph Lewis Dapao Yu Li Zhou Linhai Jiang Limin Dai 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第2期410-419,共10页
The Natural Forest Protection Program(NFPP)is one of the key ecological forestry programs in China.It not only facilitates the improvement of forest ecological quality in NFPP areas,but also plays a significant role i... The Natural Forest Protection Program(NFPP)is one of the key ecological forestry programs in China.It not only facilitates the improvement of forest ecological quality in NFPP areas,but also plays a significant role in increasing the carbon storage of forest ecosystems.The program covers 17 provinces,autonomous regions,and municipalities with correspondingly diverse forest resources and environments,ecological features,engineering measures and forest management regimes,all of which affect regional carbon storage.In this study,volume of timber harvest,tending area,pest-infested forest,firedamaged forest,reforestation,and average annual precipitation,and temperature were evaluated as factors that influence carbon storage.We developed a vector autoregression model for these seven indicators and we studied the dominant factors of carbon storage in the areas covered by NFPP.Timber harvest was the dominant factorinfluencing carbon storage in the Yellow and Yangtze River basins.Reforestation contributed most to carbon storage in the state-owned forest region in Xinjiang.In state-owned forest regions of Heilongjiang and Jilin Provinces,the dominant factors were forest fires and forest cultivation,respectively.For the enhancement of carbon sequestration capacity,a longer rotation period and a smaller timber harvest are recommended for the Yellow and Yangtze River basins.Trees should be planted in stateowned forests in Xinjiang.Forest fires should be prevented in state-owned forests in Heilongjiang,and greater forest tending efforts should be made in the state-owned forests in Jilin. 展开更多
关键词 Forest carbon storage Influencing factors natural forest protection program Variance decomposition Vector autoregression(VAR) model
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Urban Expansion and Its Influencing Factors in Natural Wetland Distribution Area in Fuzhou City,China 被引量:8
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作者 CAI Yuanbin ZHANG Hao +2 位作者 PAN Wenbin CHEN Yanhong WANG Xiangrong 《Chinese Geographical Science》 SCIE CSCD 2012年第5期568-577,共10页
This paper principally focuses on land use dynamics,urban expansion and underlying driving forces in the Natural Wetland Distribution Area(NWDA)of Fuzhou City in the southeastern China.Based on time series Landsat TM/... This paper principally focuses on land use dynamics,urban expansion and underlying driving forces in the Natural Wetland Distribution Area(NWDA)of Fuzhou City in the southeastern China.Based on time series Landsat TM/ETM+imageries and historical data,relationships between urban land expansion and its influencing factors from 1989 to 2009 were analyzed by using an integrated approach of remote sensing(RS)and geographic information system(GIS)techniques.The results showed that built-up land increased from 151.16 km2in 1989 to 383.76 km 2in 2009. Approximately 64.25%of the newly emerging built-up land was converted from cropland(29.47%),forest and shrub (25.78%),water(3.73%),wetland(4.61%),and bare land(0.66%)during 1989 and 2009.With a remarkable decrease in cropland,the proportion of non-agricultural population increased by 23.6%.Moreover,rapid development of infrastructures,facilities,industrial parks,and urban and rural settlements along the Minjiang River resulted in the eastward and southward expansion of built-up land.Additionally,the growth pattern of built-up land in the NWDA is highly correlated with socio-economic factors,including the gross domestic product(GDP),GDP per capita,and structure of industry.As a result,the observed environmental degradation such as loss of cropland and wetland due to heavy pressure of rapid urbanization have greatly impaired the carrying capacity of city.Thus,in addition to scientific and rational policies towards minimizing the adverse effects of urbanization,coordination between the administrative agencies should be urgently strengthened to balance the conflicts between urban development and ecological conservation to make sure the sustainable land use. 展开更多
关键词 land use urban expansion natural wetland socio-economic factors remote sensing (RS) geographic in-formation system (GIS)
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Natural Gas Types,Distribution Controlling Factors,and Future Exploration in the Western Qaidam Basin 被引量:3
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作者 GUO Zeqing SUN Ping +5 位作者 LI Jian ZHANG Lin LIU Weihong TIAN Jixian ZHANG Shaosheng ZENG Xu 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第4期1214-1226,共13页
The Paleogene and Neogene oil and gas in the western Qaidam basin have a regular distribution in three concentric zones from the edge to the center of the basin. Natural gas mainly occurs in the inner zone, and the ga... The Paleogene and Neogene oil and gas in the western Qaidam basin have a regular distribution in three concentric zones from the edge to the center of the basin. Natural gas mainly occurs in the inner zone, and the gas-oil ratio of the northern area of the basin is significantly higher than that of the southern area. Large amounts of carbon isotope data of natural gas, plotted in X- shaped and comprehensive identification diagrams for the southern area and northern area, respectively, were used to identify the types of natural gas. The large-scale distribution of natural gas is highly consistent with the Ro values of major source rocks, but is poorly correlated with the type of organic matter. This indicates that the main controlling factor of natural gas distribution is organic matter maturity, and the kerogen types act as the basis for the formation of different types of natural gas. Paleouplifts and squeezed anticlines near hydrocarbon generation depression centers, which are major natural gas-rich regions, control the migration directions of natural gas, while hydrocarbon migration pathways and fault systems connecting gas sources are the most important factors for natural gas reservoir formation in the inner basin. Therefore, favorable zones for natural gas distribution can be predicted on the basis of the distribution of thermal evolution and the gas generation intensity of major source rocks as well as the structural map. The Shizigou-Youshashan- Yingdong-Dawusi, Youquanzi -Kaitemilike - Youdunzi, and Xiaoliangshan - Nanyishan - Dafengshan structural belts are favorable zones for natural gas accumulation. This study has important theoretical and practical significance for future natural gas exploration. 展开更多
关键词 western Qaidam basin natural gas types distributional characteristics main controlling factors MATURITY favorable zones
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Vegetation Dynamics and Its Relationship with Climatic Factors in the Changbai Mountain Natural Reserve 被引量:5
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作者 H0U Guanglei ZHANG Hongyan WANG Yeqiao 《Journal of Mountain Science》 SCIE CSCD 2011年第6期865-875,共11页
This study examined the temporal variation of the Normalized Difference Vegetation Index (NDVI) and its relationship with climatic factors in the Changbai Mountain Natural Reserve (CMNR) during 2000 - 2009. The re... This study examined the temporal variation of the Normalized Difference Vegetation Index (NDVI) and its relationship with climatic factors in the Changbai Mountain Natural Reserve (CMNR) during 2000 - 2009. The results showed as follows. The average NDVI values increased at a rate of 0.0024 year-1. The increase rate differed with vegetation types, such as 0.0034 year-1 for forest and 0.0017 year-1 for tundra. Trend analyses revealed a consistent NDVI increase at the start and end of the growing season but little variation or decrease observed in July during the study period. The NDVI in CMNR showed a stronger correlation with temperature than with precipitation, especially in spring and autumn. A stronger correlation was observed between NDVI and temperature in the tundra zone (2,000-2,600m) than in the coniferous forest (1,100-1,700m) and Korean pine-broadleaved mixed forest (7oo-1,1oom) zones. The results indicate that vegetation at higher elevations is more sensitive to temperature change. NDVI variation had a strong correlation with temperature change (r=0.7311, p〈0.01) but less significant correlation with precipitation change. The result indicates that temperature can serve as a main indicator of vegetation sensitivity in the CMNR. 展开更多
关键词 Changbai Mountain natural Reserve Remote sensing SPOT/VGT NDVI Climatic factors
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Effects of natural mineral-rich water consumption on the expression of sirtuin 1 and angiogenic factors in the erectile tissue of rats with fructose-induced metabolic syndrome 被引量:2
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作者 Cidalia D Pereira Milton Severo +2 位作者 Luisa Rafael Maria Joao Martins Delminda Neves 《Asian Journal of Andrology》 SCIE CAS CSCD 2014年第4期631-638,共8页
Consuming a high-fructose diet induces metabolic syndrome (MS)-Iike features, including endothelial dysfunction. Erectile dysfunction is an early manifestation of endothelial dysfunction and systemic vascular diseas... Consuming a high-fructose diet induces metabolic syndrome (MS)-Iike features, including endothelial dysfunction. Erectile dysfunction is an early manifestation of endothelial dysfunction and systemic vascular disease. Because mineral deficiency intensifies the deleterious effects of fructose consumption and mineral ingestion is protective against MS, we aimed to characterize the effects of 8weeks of natural mineral-rich water consumption on the structural organization and expression of vascular growth factors and receptors on the corpus cavernosum (CC) in 10% fructose-fed Sprague-Dawley rats (FRUCT). Differences were not observed in the organization of the CC either on the expression of vascular endothelial growth factor (VEGF) or the components of the angiopoietins/Tie2 system. However, opposing expression patterns were observed for VEGF receptors (an increase and a decrease for VEGFR1 and VEGFR2, respectively) in FRUCT animals, with these patterns being strengthened by mineral-rich water ingestion. Mineral-rich water ingestion (FRUCTMIN) increased the proportion of smooth muscle cells compared with FRUCT rats and induced an upregulatory tendency of sirtuin I expression compared with the control and FRUCT groups. Western blot results were consistent with the dual immunofluorescence evaluation. Plasma oxidized low-density lipoprotein and plasma testosterone levels were similar among the experimental groups, although a tendency for an increase in the former was observed in the FRUCTMIN group. The mineral-rich water-treated rats presented changes similar to those observed in rats treated with MS-protective polyphenol-rich beverages or subjected to energy restriction, which led us to hypothesize that the effects of mineral-rich water consumption may be more vast than those directly observed in this study. 展开更多
关键词 ANGIOPOIETINS erectile tissue hypersaline sodium-rich naturally sparkling mineral water receptors sirtuin 1 vascularendothelial growth factor
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Analysis of influencing factors on suction capacity in seabed natural gas hydrate by cutter-suction exploitation 被引量:2
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作者 XU Hai-liang KONG Wei-yang HU Wen-gang 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第12期2883-2895,共13页
The mathematical and simulation models of working head in the deep-sea working environment were built to analyze the effects of cutter-suction flow,cutter-head rotating speed,cutting depth and suction port position on... The mathematical and simulation models of working head in the deep-sea working environment were built to analyze the effects of cutter-suction flow,cutter-head rotating speed,cutting depth and suction port position on the cutter-suction capacity.The efficiency of the cutter-suction is analyzed based on the analysis of the variation law of the solid-phase volume fraction of the flow field,the variation law of the velocity distribution in the flow field and the distribution law of the solid-phase concentration.The results show that the increase of cutter-suction flow can significantly improve the cutter-suction efficiency when it is less than1000m3/h.However,when it is more than1000m3/h,it is helpless.When the cutter-head rotate speed is within the range of10–25r/min,the cutter-suction efficiency stabilizes at about95%.While the speed is greater than25r/min,the cutter-suction efficiency decreases sharply with the increase of cutter-head rotate speed.With the increase of cutting depth,the cutter-suction efficiency first increases and then remains stable and finally decreases.The cutter-suction efficiency remains at about94%when the suction port position deviation ranges from0°to30°,but it has a sharply reduction when the deviation angle is more than30°. 展开更多
关键词 seabed natural gas hydrate working head solid-liquid two-phase flow cutter-suction capacity influencing factor
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An accurate empirical correlation for predicting natural gas compressibility factors 被引量:1
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作者 Ehsan Sanjari Ebrahim Nemati Lay 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2012年第2期184-188,共5页
The compressibility factor of natural gas is an important parameter in many gas and petroleum engineering calculations. This study presents a new empirical model for quick calculation of natural gas compressibility fa... The compressibility factor of natural gas is an important parameter in many gas and petroleum engineering calculations. This study presents a new empirical model for quick calculation of natural gas compressibility factors. The model was derived from 5844 experimental data of compressibility factors for a range of pseudo reduced pressures from 0.01 to 15 and pseudo reduced temperatures from 1 to 3. The accuracy of the new empirical correlation has been compared with commonly used existing methods. The comparison indicates the superiority of the new empirical model over the other methods used to calculate compressibility factor of natural gas with average absolute relative deviation percent (AARD%) of 0.6535. 展开更多
关键词 natural gas compressibility factor CORRELATION empirical model equation of state
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Analysis of factors influencing the Henry Hub natural gas price based on factor analysis 被引量:1
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作者 Hong Li Hui-Ming Zhang +1 位作者 Yuan-Tao Xie Di Wang 《Petroleum Science》 SCIE CAS CSCD 2017年第4期822-830,共9页
Henry Hub as an important transaction hub for natural gas sets the gas price standard in the USA. In this paper, the factors influencing Henry Hub natural gas prices are analyzed, and the major factors determining the... Henry Hub as an important transaction hub for natural gas sets the gas price standard in the USA. In this paper, the factors influencing Henry Hub natural gas prices are analyzed, and the major factors determining the price levels in the period between January 1997 and December 2016 are studied. It is found that economic conditions, total energy demand, US dollar exchange rate and gas consumption are the major factors. The mechanism of each factor influencing the Henry Hub natural gas price is also explored in the paper. 展开更多
关键词 natural gas Henry Hub Factor analysis
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What Do Seedlings Like? The Relationship between Seedling Richness and Abundance with Abiotic Factors
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作者 Johnatan Jair de Paula Marchiori Vinicius de Souza Oliveira +7 位作者 Eduarda Carriço Ana Clara Bayer Bernabé Anderson Mathias Holtz Ronilda Lana Aguiar Ana Beatriz Mamedes Piffer Gilcéa Teixeira Fontana Boone Ricardo Amaro de Sales Lusiane de Sousa Ferreira 《Agricultural Sciences》 2023年第6期767-774,共8页
Natural regeneration is the interaction of natural processes to restore the forest ecosystem. Its dynamics are influenced by the intensity and extent of a series of abiotic and biotic factors, which may be intrinsic o... Natural regeneration is the interaction of natural processes to restore the forest ecosystem. Its dynamics are influenced by the intensity and extent of a series of abiotic and biotic factors, which may be intrinsic or extrinsic. Knowing the importance of establishing natural regeneration within forest ecosystems, this work aimed to evaluate whether litter depth and trail distance influenced seedling abundance and richness in a forest fragment undergoing natural restoration. The hypothesis tested in this research was that abiotic factors influence the natural regeneration of this forest since they are factors that are directly linked to seed germination and seedling establishment. 30 plots of 1 m2 were randomly analyzed within the forest located on the brown trail. A millimeter ruler was used to diagnose the litter depth and a measuring tape to measure the distance from the plot to the edge. In each plot the seedlings were morpho-specified and each morphospecies had the number of individuals counted. Linear regression tests were performed to assess the relationships between species richness and trail distance and litter depth. The same was done for species abundance. All results showed that there is no relationship pattern between any of the variables. Other factors also influence the regeneration of a forest, such as luminosity and seed bank. Furthermore, litter depth is related to the successional stage of the forest. It was concluded that the abiotic factors tested do not influence the regeneration of the study area. 展开更多
关键词 Abiotic factors natural Regeneration Forest Ecosystem
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The Variation of Plankton Community Structure in Artificial Reef Area and Adjacent Waters in Haizhou Bay
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作者 GAO Shike SHI Yixi +1 位作者 LU Yanan ZHANG Shuo 《Journal of Ocean University of China》 CAS CSCD 2024年第1期264-276,共13页
Plankton are an important component of marine protected areas(MPAs),and its communities would require much smaller interpatch distances to ensure connection among MPAs.According to the survey from MPAs dominated by ar... Plankton are an important component of marine protected areas(MPAs),and its communities would require much smaller interpatch distances to ensure connection among MPAs.According to the survey from MPAs dominated by artificial reefs and adjacent waters(estuary area(EA),aquaculture area(AA),artificial reef area(ARA),natural area(NA)and comprehensive effect area(CEA))in Haizhou Bay in spring and autumn,we analyzed phyto-zooplankton composition,abundance and biomass,and correlation with hydrologic variables to gain information about the forces that structure the plankton.The results showed that the dominant zooplankton were copepods(spring,98.9%;autumn,94.2%),while the phytoplankton were mainly composed of Bacillariophyta(spring,61.8%;autumn,95.6%).The RDA results showed that temperature,salinity and depth highly associated with the distribution and composition of plankton species among the habitats than other factors in spring;temperature,Chla and DO had the strongest influence in autumn.The zooplankton in the ARA and AA ecosystems basically contained the same species as those in other habitats,and each habitat also exhibited a relatively unique combination of plankton species.The structures of the EA zooplankton in spring and the EA phytoplankton in both seasons were much different than other habitats,which may have been caused by factors such as currents and tides.We concluded that there exists similarity of the plankton community between artificial reef area and adjacent waters,whereas the EAs may be relatively independent systems.Therefore,these interaction between plankton community should be considered when designing MPA networks,and ocean circulations should be considered more than the environmental factors. 展开更多
关键词 ZOOPLANKTON PHYTOPLANKTON seasonal variation environmental factor artificial reef
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Predictive active control of building structures using LQR and artificial intelligence
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作者 Nirmal S.Mehta Vishisht Bhaiya +1 位作者 K.A.Patel Ehsan Noroozinejad Farsangi 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第2期489-502,共14页
This study presents a neural network-based model for predicting linear quadratic regulator(LQR)weighting matrices for achieving a target response reduction.Based on the expected weighting matrices,the LQR algorithm is... This study presents a neural network-based model for predicting linear quadratic regulator(LQR)weighting matrices for achieving a target response reduction.Based on the expected weighting matrices,the LQR algorithm is used to determine the various responses of the structure.The responses are determined by numerically analyzing the governing equation of motion using the state-space approach.For training a neural network,four input parameters are considered:the time history of the ground motion,the percentage reduction in lateral displacement,lateral velocity,and lateral acceleration,Output parameters are LQR weighting matrices.To study the effectiveness of an LQR-based neural network(LQRNN),the actual percentage reduction in the responses obtained from using LQRNN is compared with the target percentage reductions.Furthermore,to investigate the efficacy of an active control system using LQRNN,the controlled responses of a system are compared to the corresponding uncontrolled responses.The trained neural network effectively predicts weighting parameters that can provide a percentage reduction in displacement,velocity,and acceleration close to the target percentage reduction.Based on the simulation study,it can be concluded that significant response reductions are observed in the active-controlled system using LQRNN.Moreover,the LQRNN algorithm can replace conventional LQR control with the use of an active control system. 展开更多
关键词 active control system linear quadratic regulator artificial neural networks state-space approach response effectiveness factor RESILIENCE
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ON THE RELATION BETWEEN THE EVOLUTION OF NATURAL ENVIRONMENT AND HUMAN FACTORS AND THE DEVELOPMENT OF URBAN SETTLEMENT——Take the Lanzhou Valley Basin as An Examples
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作者 鲜肖威 张林源 +1 位作者 艾南山 Wihelm Wohlke 《Chinese Geographical Science》 SCIE CSCD 1991年第1期44-55,共12页
Lanzhou Valley Basin is composed of two smaller diamond-shaped basins striking from NW to SE and including 6 river terraces. The lower terraces remaining even and smooth are main sites for city buildings. The main fun... Lanzhou Valley Basin is composed of two smaller diamond-shaped basins striking from NW to SE and including 6 river terraces. The lower terraces remaining even and smooth are main sites for city buildings. The main function of Lanzhou urban settlement is a ferry and transport centre. Lanzhou used to be an im-portant crossing site and post on the 'silk road',and then became a transport and trade centre in Northwest China. In the middle part of the 17th century, Lanzhou became the capital of Gansu,a new province. The development process of Lanzhou urban settlement indicates that urban settlement is a system consisting of natural environment and human society based on the former. 展开更多
关键词 natural environment human factor URBAN SETTLEMENT interface analysis QUATERNARY
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Human-artificial intelligence interaction in gastrointestinal endoscopy
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作者 John R Campion Donal B O'Connor Conor Lahiff 《World Journal of Gastrointestinal Endoscopy》 2024年第3期126-135,共10页
The number and variety of applications of artificial intelligence(AI)in gastr-ointestinal(GI)endoscopy is growing rapidly.New technologies based on machine learning(ML)and convolutional neural networks(CNNs)are at var... The number and variety of applications of artificial intelligence(AI)in gastr-ointestinal(GI)endoscopy is growing rapidly.New technologies based on machine learning(ML)and convolutional neural networks(CNNs)are at various stages of development and deployment to assist patients and endoscopists in preparing for endoscopic procedures,in detection,diagnosis and classification of pathology during endoscopy and in confirmation of key performance indicators.Platforms based on ML and CNNs require regulatory approval as medical devices.Interactions between humans and the technologies we use are complex and are influenced by design,behavioural and psychological elements.Due to the substantial differences between AI and prior technologies,important differences may be expected in how we interact with advice from AI technologies.Human-AI interaction(HAII)may be optimised by developing AI algorithms to minimise false positives and designing platform interfaces to maximise usability.Human factors influencing HAII may include automation bias,alarm fatigue,algorithm aversion,learning effect and deskilling.Each of these areas merits further study in the specific setting of AI applications in GI endoscopy and professional societies should engage to ensure that sufficient emphasis is placed on human-centred design in development of new AI technologies. 展开更多
关键词 artificial intelligence Machine learning Human factors Computer-aided detection COLONOSCOPY Adenoma detection rate
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