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Impacts of channel dredging on hydrodynamics and sediment dynamics in the main channels of the Jiaojiang River Estuary in China
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作者 Yanming Yao Xueqian Chen +2 位作者 Jinxiong Yuan Li Li Weibing Guan 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第9期132-144,共13页
Channel dredging in estuaries increases water depth and subsequently impacts sediment dynamics and morphology. The Jiaojiang River Estuary is dredged frequently owing to heavy shipping demands. In this study,the effec... Channel dredging in estuaries increases water depth and subsequently impacts sediment dynamics and morphology. The Jiaojiang River Estuary is dredged frequently owing to heavy shipping demands. In this study,the effects of different dredging schemes on siltation were assessed through numerical modeling. The sediment model of the Jiaojiang River Estuary utilized an optimized bottom boundary layer model that considered the bed sediment grain size and fluid mud, and this model was calibrated using field data. Result reveal that channel dredging modifies the flow velocity inside and around the channel by changing the bathymetry;subsequently, this affects the residual current, bed stress, suspended sediment concentration, and sediment fluxes. Increasing the dredging depth and width increases the net sediment fluxes into the channel and dredging depth has a greater influence on the channel siltation thickness. When the dredging depth is 8.4 m or11.4 m, the average siltation thickness of the channel is 0.07 m or 0.15 m per mouth respectively. The parallel movement of the channel has small effects on the siltation volume during the simulation period. The sediment deposits in the channel primarily originates from the tidal flats, through bottom sediment fluxes. Vertical net circulation has a dominant impact on siltation because the difference of horizontal current of each layer on the longitudinal section of the channel increases, which intensifies the lateral sediment transport between the shoal and channel. The influence of vertical frictional dissipation on the lateral circulation at the feature points accounts for more than 50% before dredging, while the non-linear advective term is dominant after dredging. Tidal pumping mainly affects the longitudinal sediment fluxes in the channel. These results can be used for channel management and planning for similar estuaries worldwide. 展开更多
关键词 sediment dynamics channel dredging bottom boundary layer SILTATION Jiaojiang River Estuary
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Advances in Research of Treatment of Angina Pectoris in Coronary Heart Disease from the Method of Dredging Collaterals with Pungent
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作者 Sihui WANG Yan SHEN 《Medicinal Plant》 CAS 2023年第2期84-89,共6页
The angina pectoris in coronary heart disease belongs to the category of"chest impediment"in traditional Chinese medicine,and belongs to the syndrome of root deficiency with tip excess.Its main pathogenesis ... The angina pectoris in coronary heart disease belongs to the category of"chest impediment"in traditional Chinese medicine,and belongs to the syndrome of root deficiency with tip excess.Its main pathogenesis is obstruction of the heart collaterals,and treatment mainly adopts dredging collaterals and relieving pain.Based on the treatment principles of dredging collaterals with pungent,aiming at the etiology,pathogenesis and disease characteristics of angina pectoris in coronary heart disease,this article systematically analyzes the Method of Dredging Collaterals with Pungent including the methods of dredging collaterals with pungent moisture,dredging collaterals with pungent warm,dredging collaterals with pungent aroma,and dredging collaterals with insect type drugs,to provide ideas for the treatment of angina pectoris in coronary heart disease. 展开更多
关键词 Coronary heart disease Angina pectoris Chest impediment Collateral diseases Impediment of heart collaterals Method of dredging Collaterals with Pungent
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Impact of Dredging on Coastal Infrastructure: Case Studies from Okrika and Port Harcourt, Niger Delta
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作者 Tamunoene Kingdom Simeon Abam Ferdinand Dumbari Giadom Robert Egwu Otu Iduma 《Journal of Geoscience and Environment Protection》 2023年第5期349-362,共14页
Sand excavations in river beds have compromised the safety of several bridges in recent years. Large scale sand mining from river beds is now common in the Niger Delta, due to the necessity of reclaiming land for deve... Sand excavations in river beds have compromised the safety of several bridges in recent years. Large scale sand mining from river beds is now common in the Niger Delta, due to the necessity of reclaiming land for development purposes and to meet construction needs in the region. There is currently no regulation as to where sand can be mined in river channels because of the lack of adequate understanding of the risks to coastal infrastructure involved with its abstraction. The phenomenon of bridge Abutment and bank failure induced by excessive dredging of sand river bed is considered. Two types of instability were distinguished, one relating to the equilibrium slope of the riverbed and the other riverbank instability. An empirical relationship in the form X<sub>s</sub> = 3Htan(90 - α) has been developed through analysis, supported by examples that a minimum distance of 94 m (for sand river beds) from a bridge should be observed for sand abstraction in order to guaranty the safety of bridge foundation. For clay riverbeds, slightly shorter minimum distances can be considered safe. The study further shows that the capacity of sand borrowing in river channels to generate bank instability is dependent on the composition and stratigraphy beneath the river bed. 展开更多
关键词 dredging IMPACTS Coastal Infrastructure Niger Delta
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Significance of dredging on sediment denitrification in Meiliang Bay,China:A year long simulation study 被引量:41
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作者 Jicheng Zhong Chengxin Fan +4 位作者 Lu Zhang Edward Hall Shiming Ding Bao Li Guofeng Liu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2010年第1期68-75,共8页
An experiment for studying the effects of sediment dredging on denitrification in sediments was carried out through a one-year incubation of undredged (control) and dredged cores in laboratory. Dredging the upper 30... An experiment for studying the effects of sediment dredging on denitrification in sediments was carried out through a one-year incubation of undredged (control) and dredged cores in laboratory. Dredging the upper 30 cm of sediment can significantly affect physico-chemical characteristics of sediments. Less degradation of organic matter in the dredged sediments was found during the experiment. Denitrification rates in the sediments were estimated by the acetylene blockage technique, and ranged from 21.6 to 102.7 nmol N2/(g dry weight (dw)-hr) for the undredged sediment and from 6.9 to 26.9 nmol N2/(g dw-hr) for dredged sediments. The denitrification rates in the undredged sediments were markedly higher (p 〈 0.05) than those in the dredged sediments throughout the incubation, with the exception of February 2006. The importance of various environmental factors on denitrification was assessed, which indicated that denitrification was regulated by temperature. Nitrate was probably the key factor limiting denitrification in both undredged and dredged sediments. Organic carbon played some role in determining the denitrification rates in the dredged sediments, but not in the undredged sediments. Sediment dredging influenced the mineralization of organic matter and denitrification in the sediment; and therefore changed the pattern of inherent cycling of nitrogen. 展开更多
关键词 sediment dredging DENITRIFICATION Taihu Lake
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Clinical analysis of pipeline dredging agent poisoning:A case report
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作者 Ya-Qian Li Guang-Cai Yu +4 位作者 Long-Ke Shi Li-Wen Zhao Zi-Xin Wen Bao-Tian Kan Xiang-Dong Jian 《World Journal of Clinical Cases》 SCIE 2022年第28期10201-10207,共7页
BACKGROUND Pipeline dredging agents are new household deep cleaning products used to dredge blockages in kitchen and bathroom pipeline caused by grease,hair,vegetable residue,paper cotton fibre,and other organic subst... BACKGROUND Pipeline dredging agents are new household deep cleaning products used to dredge blockages in kitchen and bathroom pipeline caused by grease,hair,vegetable residue,paper cotton fibre,and other organic substances.Pipeline dredging agents are corrosive chemicals that can cause poisoning through corrosive damage to the digestive tract;however,this has not been reported clinically.Therefore,this report emphasises that oral pipeline dredging agent poisoning can cause corrosive damage to the digestive tract and may have serious health consequences.CASE SUMMARY A 68-year-old man consumed liquor(200 m L) at approximately 13:00 on April 22,2021.At approximately 16:00,his family found him unresponsive with blackened lips,blood spots in the corners of the mouth,and blood stains on the ground,as well as an empty bottle of a pipeline dredging agent.One hour later,he was admitted to the emergency department of a local hospital.Considering the empty bottle,he was suspected to have sustained severe corrosive damage to the digestive tract and was transferred to our department at 23:15 on April 22,2021.He developed dysphagia and intermittent fever and experienced difficulty in opening his mouth throughout his hospital stay.The patient’s condition gradually stabilised.However,he suddenly developed respiratory failure on day 12,and endotracheal intubation and ventilator-assisted ventilation were performed.However,the patient died after 1.5 h despite emergency rescue efforts.CONCLUSION Pipeline dredging agents are highly corrosive and may cause corrosive damage to the digestive tract and asphyxia upon consumption. 展开更多
关键词 ASPHYXIA Digestive tract injury Pipeline dredging agent POISONING Respiratory failure Case report
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Evaluation of Dredging Operations for Tigris River within Baghdad, Iraq
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作者 Ammar Ali Qusay Al-Suhail +1 位作者 Nadhir Al-Ansari Sven Knutsson 《Journal of Water Resource and Protection》 2014年第4期202-213,共12页
River Tigris divides Baghdad, capital of Iraq, in two parts. The reach of the river within Baghdad is about 60 km long. Many islands and bars are obstructing the flow of the river within Baghdad. To overcome this prob... River Tigris divides Baghdad, capital of Iraq, in two parts. The reach of the river within Baghdad is about 60 km long. Many islands and bars are obstructing the flow of the river within Baghdad. To overcome this problem, dredging operations started along most of Tigris River inside Baghdad City to remove many islands and side bars, which reduced the flooding capacity and the efficiency of water intakes. An examination for the dredging plan under process and two proposed additional plans was performed using the Hydrologic Engineering Centers River Analysis System software (HEC-RAS) for a 50 km long river reach to investigate whether they can recover the designed flooding capacity of the river or just improving it. Calibration and verification processes were implemented in the model using observed water levels at Sarai Baghdad gauging station and along the last 15 km of the river reach. Comparisons of computed water levels were conducted with those of previous studies and historical data. Some improvement of flood capacity was achieved based on the recorded data of the last three decades. Cautions about the water intakes should be considered to maintain their function with the expected drop in water level due to dredging operations. 展开更多
关键词 Baghdad dredging FLOODING Capacity Tigris RIVER
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Study on Key Problems of a New Environmental Dredging Based on Ecological Protection and Subsequent Ecological Restoration
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作者 HU Wei 《Meteorological and Environmental Research》 CAS 2012年第11期47-49,53,共4页
[Objective] The research aimed to study key problems of a new environmental dredging based on ecological protection and subsequent ecological restoration. [Method] People paid more attention to sediment pollutant remo... [Objective] The research aimed to study key problems of a new environmental dredging based on ecological protection and subsequent ecological restoration. [Method] People paid more attention to sediment pollutant removal in environmental dredging, without considering coming aquatic eco-restoration work after dredging. Factor affecting aquatic ecosystem existence and growth was screened, and ecological dredging manner was put forward. [Result] On the basis of analyzing dredging objective, effect and influence, started from ecological protection and subsequent ecological restoration, water depth and substrate were screened as priority control factors of the environmental sediment dredging. New manner of combining sediment dredging to reshape underwater terrain was put forward. [Conclusion] The research provided solution for water depth and substrate demands of the subsequent ecological restoration. 展开更多
关键词 Ecological protection Subsequent ecological restoration Environmental dredging Key problem China
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Clinical observation on efficacy of compound of warming yang, descending turbidity and dredging collaterals in the treatment of diabetic kidney disease with Yin-Yang deficiency and blood stasis syndrome
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作者 Li-Bei Zhan Xiao-Dong Xiong Kai Zhao 《Journal of Hainan Medical University》 2020年第21期26-31,共6页
Objective:To observe the clinical efficacy of compound of owarming yang,descending turbidity and dredging collaterals in the treatment of diabetic kidney disease with yin-yang deficiency and blood stasis syndrome.Meth... Objective:To observe the clinical efficacy of compound of owarming yang,descending turbidity and dredging collaterals in the treatment of diabetic kidney disease with yin-yang deficiency and blood stasis syndrome.Methods:Seventy-six patients of diabetic kidney disease with yin-yang deficiency and blood stasis syndrome were randomly divided into observation group and control group,thirty-eight cases in each group.The control group was given conventional western medicine treatment,while the observation group took compound of owarming yang,descending turbidity and dredging collaterals orally on the basis of conventional western medicine treatment.The course of treatment covered for one month.Before and after treatment,we observed the scores of traditional Chinese medicine symptoms,indicators of renal function[serum creatinine(Scr),blood urea nitrogen(BUN),microalbuminuria(MALB)],indicators of glucose metabolism[fasting plasma glucose(FPG),2-hour postprandial blood glucose(2hPG),glycosylated hemoglobin(HbAlc)],indicators of hemorheology[plasma viscosity(PV),platelet aggregation rate(PAR),fibrinogen(FIB)],Cystatin-C(Cys-C),C-reactive protein(CRP)in the two groups.Results:After treatment,the clinical effect of the observation group was significantly better than the control group(P<0.05).The scores of traditional Chinese medicine symptoms,indicators of renal function(Scr、BUN、UAER),indicators of glucose metabolism(FPG、2hPG、HbAlc),indicators of hemorheology(PV、PAR、FIB),Cys-C and CRP in the two groups were decreased significantly compared with those before treatment(P<0.05),and the decrease in the observation group was superior to that in the control group(P<0.05).Conclusion:Compound of warming yang,descending turbidity and dredging collaterals has remarkable efficacy in treating of diabetic kidney disease patients with yin-yang deficiency and blood stasis syndrome by alleviating clinical symptoms,glucose metabolism,renal function and microcirculatory disturbance,and the mechanism related to alleviation of microinflammation. 展开更多
关键词 Compound of warming yang Descending turbidity and dredging collaterals Diabetic kidney disease Yin-yang deficiency and blood stasis syndrome
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Measuring the Total Economic Value of Traditional Sand Dredging in the Coastal Lagoon Complex of Grand-Nokoué(Benin)
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作者 Metogbe B. Djihouessi Martin P. Aina +1 位作者 Ben-Vital Kpanou Nadine Kpondjo 《Journal of Environmental Protection》 2017年第13期1605-1621,共17页
Sand is a crucial resource for society’s development. Among the most exploited sand quarries in the world are the lagoon and wetland sand. Although mechanical sand dredging is the most spread technique, manual and tr... Sand is a crucial resource for society’s development. Among the most exploited sand quarries in the world are the lagoon and wetland sand. Although mechanical sand dredging is the most spread technique, manual and traditional techniques are still widely used in West Africa. The purpose of this paper is twofold: to describe traditional sand dredging (TSD), highlighting the procedure used and the structural organization of this activity, and to evaluate the total economic value of TSD in order to help decision making about wetland management. Therefore, TSD occurring in the coastal lagoon complex of Grand Nokoué (CLCGN) in Benin was investigated. Field surveys indicate that TSD is mainly dominated by men, about 93% of the actors. It required intense physical efforts including diving to the bottom of the lake and removing manually the sand in backed toward the surface of the water. TSD actors are organized in local associations which deliver extraction license and discuss with both the others actors and the local government. The total economic value of the benefits of TSD to the population, estimated using direct market value and replacement cost, was estimated at 2.44 million USD per year for 127,818 m3 of sand extracted. It is clear that introduction of mechanical sand dredging will increase the amount the sand removed and subsequently will increase some benefits such as reduction of flooding amplitude and mitigation of the filling of the lakes. However, mechanical sand removal will also considerably reduce the profit the local population makes from sand commercialization which currently represents 80% the total economic value of TSD. 展开更多
关键词 TRADITIONAL SAND dredging ECOSYSTEM Service COASTAL Lake
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Impacts of Dredging on Fluvial Geomorphology in the Jamuna River, Bangladesh
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作者 Md Mosiur Rahman Md Sazadul Hasan +1 位作者 Moniruzzaman Khan Eusufzai Md Munsur Rahman 《Journal of Geoscience and Environment Protection》 2021年第6期1-20,共20页
Jamuna, a major braided river in Bangladesh, has an enormous hydrological impact on the surrounding areas and streams. Erosion and sedimentation in the Jamuna river cause a large flow fluctuation and floods round the ... Jamuna, a major braided river in Bangladesh, has an enormous hydrological impact on the surrounding areas and streams. Erosion and sedimentation in the Jamuna river cause a large flow fluctuation and floods round the year. Bangladesh Water Development Board has initiated a pilot capital dredging project in the Jamuna river in 2011-2012, aiming to guide the flow to reduce the risk of failure of the city area and right guide bundh of the Jamuna Bridge. This study explores the long-term role of dredging on river morphology us-ing erosion-sedimentation numerical modeling approaches. Primary data were employed in numerical models to estimate the erosion-sedimentation and compared outputs with the real-time cross-sectional variation at selected sections along the reach during 2012-2013. The analysis suggested that the rate of sedimentation is higher (60% to 80%), where the dredging alignment crosses through the existing sandbar/char. Moreover, a cross-section com-parison revealed that the channel near Sirajganj Hardpoint shifted towards the left (east) bank, and the channel within the study area developed very fast along the right (west) bank. However, satellite image analysis revealed that the major bankline shifting occurred from 2000 to 2010 and the channel shifting was observed from 2014 to 2018 along the reach, mostly, after the construction of some river training works. The variation of the channel per-sistence (40% - 100%) selected part of the study area in the channel inci-dence map, indicating the rapid dynamic behavior of the river morphology. This study showed a good agreement of measured data and simplified em-pirical relationships to predict the long-term morphodynamic behavior of the braided Jamuna river. 展开更多
关键词 Sediment Transport EROSION dredging Satellite Image River Morphology
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Observation on the Therapeutic Effect of Heatclearing and Dampness-eliminating Dredging Collaterals Combined with Papaya Antirheumatic Pills on Treatment of Damp-heat Obstructive Ankylosing Spondylitis
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作者 Youling Huang 《Journal of Clinical and Nursing Research》 2020年第2期57-60,共4页
Objective:Therapeutic effect of heatclearing and dampness-eliminating dredging collaterals combined with papaya antirheumatic pills on treatment of damp-heat obstructive ankylosing spondylitis.Methods:A total of 200 p... Objective:Therapeutic effect of heatclearing and dampness-eliminating dredging collaterals combined with papaya antirheumatic pills on treatment of damp-heat obstructive ankylosing spondylitis.Methods:A total of 200 patients with ankylosing spondylitis who were treated in our hospital from January 2018 to October 2019 were selected as the research objects and randomly divided into 2 groups,each with 100 patients.The control group was treated with leflunomide+papaya antirheumatic pills,and the observation group was treated with self-drafted recipe of heat-clearing and dampness-eliminating,the curative effect,visual analogue score(VAS),barthel AS function index(BASFI)score,biochemical indicators and adverse reactions between the two groups were compared.Results:After 12 weeks of treatment,the efficacy of the observation group was higher than that of the control group.The pain score,BASFI score,and biochemical index were lower than those of the control group,and the differences were statistically significant(P<0.05);There was no significant difference in the incidence of adverse reactions between the two groups(P>0.05).Conclusion:Heat-clearing and dampnesseliminating dredging collaterals combined with papaya antirheumatic pills is effective in the treatment of damp-heat obstructive ankylosing spondylitis,which is beneficial to reduce the degree of pain and inflammation of the affected area,helps patients remain active,and improves activities of daily living. 展开更多
关键词 DAMP-HEAT OBSTRUCTIVE ankylosing spondylitis Heat-clearing and dampness-eliminating dredging COLLATERALS PAPAYA antirheumatic PILLS Degree of pain The biochemical index
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Restoration or Rehabilitation of the Faleme River Affected by Mining Activities: What Methods?
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作者 Mor Diop Ibrahima Mall +3 位作者 Elhadji Mamadou Sonko Tidiane Diop Birane Niane Cheikh Mbow 《Journal of Water Resource and Protection》 CAS 2024年第4期233-263,共31页
The Faleme River, a West Africa long transboundary stream (625 km) and abundant flow (>1100 million m<sup>3</sup>) is affected by severe erosion because of mining activities that takes place throughout ... The Faleme River, a West Africa long transboundary stream (625 km) and abundant flow (>1100 million m<sup>3</sup>) is affected by severe erosion because of mining activities that takes place throughout the riverbed. To preserve this important watercourse and ensure the sustainability of its services, selecting and implementing appropriates restorations techniques is vital. In this context, the purpose of this paper was to present an overview of the actions and techniques that can be implemented for the restoration/rehabilitation of the Faleme. The methodological approach includes field investigation, water sampling, literature review with cases studies and SWOT analysis of the four methods presented: river dredging, constructed wetlands, floating treatment wetlands and chemical precipitation (coagulation and flocculation). The study confirmed the pollution of the river by suspended solids (TSS > 1100 mg/L) and heavy metals such as iron, zinc, aluminium, and arsenic. For the restoration methods, it was illustrated through description of their mode of operation and through some case studies presented, that all the four methods have proven their effectiveness in treating rivers but have differences in their costs, their sustainability (detrimental to living organisms or causing a second pollution) and social acceptance. They also have weaknesses and issues that must be addressed to ensure success of rehabilitation. For the case of the Faleme river, after analysis, floating treatment wetlands are highly recommended for their low cost, good removal efficiency if the vulnerability of the raft and buoyancy to strong waves and flow is under control. 展开更多
关键词 Faleme River River Restoration Constructed Wetlands dredging Floating Treatment Wetlands COAGULATION-FLOCCULATION
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Systemic Lupus Erythematosus Complicated with Femoral Head Ischemic Necrosis Treated by Chinese Medicine Therapy for Activating Blood and Dredging Collaterals Method 被引量:5
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作者 汪卫 于健宁 陶筱娟 《Chinese Journal of Integrative Medicine》 SCIE CAS 2011年第3期105-110,共6页
Objective:To observe the effect and mechanism of Chinese medicine therapy for activating blood and dredging collaterals(ABDC) on treating systemic lupus erythematosus complicated with avascular necrosis of the femo... Objective:To observe the effect and mechanism of Chinese medicine therapy for activating blood and dredging collaterals(ABDC) on treating systemic lupus erythematosus complicated with avascular necrosis of the femoral head(SLE-ANFH).Methods:Thirty-four patients(51 joints) with SLE-ANFH were assigned by a random number table to two groups:22 patients(32 joints) in the treatment group and 12 patients (19 joints) in the control group.All received Western medical conventional treatment for anti-inflammation and immunosuppression,but an additional Chinese medicine decoction prescribed based on ABDC principle was administered to patients in the treatment group.The observation on the patients' condition and therapeutic effect lasted for 3 years.Results:The patients' conditions in the two groups,as assessed by Association for Research Circulation Osseous(ARCO) staging,were similar before treatment.After treatment,comparison between groups showed significant difference(P0.05),and the raised Harris functional scores in the treatment group were higher than that in the control group(P0.01).The post-treatment symptom improving rate in the treated group was 72.73%,which was higher than that in the control group(50.00%,P0.05).Moreover,the former was superior in improving hematologic and hemorrheologic parameters in terms of prolonging activated partial thromboplastin time,lowering whole blood middle/low shear viscosity,and plasma viscosity(P0.05 or P0.01). Two patients in the control group but none in the treatment group received hip joint replacement operation during the observation period.Conclusions:Chinese medicine ABDC therapy could effectively alleviate clinical symptoms and improve joint function of patients with SLE-ANFH.The mechanism may be related to its effects on improving high coagulation manner and trend for getting embolism. 展开更多
关键词 systemic lupus erythematosus femoral head ischemic necrosis Chinese medicine activating blood and dredging collaterals
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Effects of sludge dredging on the prevention and control of algae-caused black bloom in Taihu Lake,China 被引量:31
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作者 Wei He Jingge Shang +1 位作者 Xin Lu Chengxin Fan 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2013年第3期430-440,共11页
Algae-caused black bloom (also known as black water agglomerate) has recently become a critical problem in some Chinese lakes.It has been suggested that the occurrence of algae-caused black bloom was caused by the c... Algae-caused black bloom (also known as black water agglomerate) has recently become a critical problem in some Chinese lakes.It has been suggested that the occurrence of algae-caused black bloom was caused by the cooperation of nutrient-rich sediment with dead algae,and sludge dredging was adopted to control black bloom in some lakes of China.In this article,based on the simulation of black bloom using a Y-shape apparatus for modeling natural conditions,both un-dredged and dredged sites in three areas of Taihu Lake,China were studied to estimate the effects of dredging on the prevention and control of black bloom.During the experiment,drained algae were added to all six sites as an additional organic load;subsequently,the dissolved oxygen decreased rapidly,dropping to 0 mg/L at the sediment-water interface.Black bloom did not occur in the dredged sites of Moon Bay and Nan Quan,whereas all three un-dredged sites at Fudu Port,Moon Bay and Nan Quan experienced black bloom.Black bloom also occurred at the dredged site of Fudu Port one day later than at the other sites,and the odor and color were lighter than at the other locations.The color and odor of the black water mainly result from the presence of sulfides such as metal sulfides and hydrogen sulfide,among other chemicals,under reductive conditions.The color and odor of the water,together with the high concentrations of nutrients,were mainly caused by the decomposition of the algae and the presence of nutrient-rich sediment.Overall,the removal of the nutrient-rich sediment by dredging can prevent the occurrence and control the degree of algae-caused black bloom in Taihu Lake. 展开更多
关键词 Taihu Lake algae-caused black bloom sediment sludge dredging
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Factors related to aggravated Cylindrospermopsis(cyanobacteria)bloom following sediment dredging in an eutrophic shallow lake 被引量:1
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作者 Xiaochuang Li Shouliang Huo +3 位作者 Jingtian Zhang Zhe Xiao Beidou Xi Renhui Li 《Environmental Science and Ecotechnology》 2020年第2期1-8,共8页
In recent years,Cylindrospermopsis raciborskii blooms have been widely found worldwide.Topics dealing with the mitigation of C.raciborskii bloom is of great importance for toxins produced could threaten public health.... In recent years,Cylindrospermopsis raciborskii blooms have been widely found worldwide.Topics dealing with the mitigation of C.raciborskii bloom is of great importance for toxins produced could threaten public health.The paper first investigated C.raciborskii dynamics over three years following sediment dredging in a shallow eutrophic Lake Dongqian(China).Based on rpoC1 gene copies,C.raciborskii bloom formed with average density of 1.30×10^(6) cells/L on July 2009.One year later after sediment dredging,C.raciborskii cell density decreased below 1.17×10^(5) cells/L or under detected limits during summer days on 2010.While two years later,the C.raciborskii bloom period was returned with markedly increased cell density reaching up to 4.15×10^(7) cells/L on October 2011,and the maximum peak density was shown at 20.3C that was much lower than reported optimal growth temperature.Inferred from Spearman correlation analysis,linear regression showed C.raciborskii density was significant and positive with pH and SD,whereas they were significant and negative with TP and DO.Multiple regression analysis further demonstrated that TN,TP,SRP,pH and DO provided the best model and explained 53.1% of the variance in C.raciborskii dynamics.The approaches managing nutrients reduction might not control C.raciborskii bloom as extremely low TN(avg.0.18 mg/L)and TP concentrations(avg.0.05 mg/L)resulted in the highest C.raciborskii cell density after sediment dredging. 展开更多
关键词 Bloom control CYLINDROSPERMOPSIS Environmental variables Sediment dredging
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Dredged marine soil stabilization using magnesia cement augmented with biochar/slag
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作者 Chikezie Chimere Onyekwena Qi Li +5 位作者 Yong Wang Ishrat Hameed Alvi Wentao Li Yunlu Hou Xianwei Zhang Min Zhang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第3期1000-1017,共18页
Dredged marine soils(DMS)have poor engineering properties,which limit their usage in construction projects.This research examines the application of reactive magnesia(rMgO)containing supplementary cementitious materia... Dredged marine soils(DMS)have poor engineering properties,which limit their usage in construction projects.This research examines the application of reactive magnesia(rMgO)containing supplementary cementitious materials(SCMs)to stabilize DMS under ambient and carbon dioxide(CO_(2))curing conditions.Several proprietary experimental tests were conducted to investigate the stabilized DMS.Furthermore,the carbonation-induced mineralogical,thermal,and microstructural properties change of the samples were explored.The findings show that the compressive strength of the stabilized DMS fulfilled the 7-d requirement(0.7-2.1 MPa)for pavement and building foundations.Replacing rMgO with SCMs such as biochar or ground granulated blast-furnace slag(GGBS)altered the engineering properties and particle packing of the stabilized soils,thus influencing their performances.Biochar increased the porosity of the samples,facilitating higher CO_(2) uptake and improved ductility,while GGBS decreased porosity and increased the dry density of the samples,resulting in higher strength.The addition of SCMs also enhanced the water retention capacity and modified the pH of the samples.Microstructural analysis revealed that the hydrated magnesium carbonates precipitated in the carbonated samples provided better cementation effects than brucite formed during rMgO hydration.Moreover,incorporating SCMs reduced the overall global warming potential and energy demand of the rMgO-based systems.The biochar mixes demonstrated lower toxicity and energy consumption.Ultimately,the rMgO and biochar blend can serve as an environmentally friendly additive for soft soil stabilization and permanent fixation of significant amounts of CO_(2) in soils through mineral carbonation,potentially reducing environmental pollution while meeting urbanization needs. 展开更多
关键词 Dredged marine soil CO_(2)uptake Reactive magnesia BIOCHAR Ground granulated blast-furnace slag
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Observation on Effect of Treatment of Alcoholic Fatty Liver by Traditional Medical Therapy of Liver -Clearing,Dampness -Re moving and Collaterals- Dredging
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作者 张诗军 劳绍贤 +1 位作者 陈泽雄 黄必军 《Chinese Journal of Integrative Medicine》 SCIE CAS 2002年第2期134-136,共3页
关键词 Re moving and Collaterals dredging Observation on Effect of Treatment of Alcoholic Fatty Liver by Traditional Medical Therapy of Liver Clearing Dampness
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Densification of Reclaimed Soils with the Utilization of the Vibro Compaction Technique—A Case Study
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作者 Emmanouil Spyropoulos Bedros Avakian 《Open Journal of Civil Engineering》 2023年第2期263-281,共19页
This paper presents a case study of the extensive soil improvement work carried out on a reclamation project on the shores of United Arab Emirates. The project consisted an area of approximately 480,000 m<sup>2&... This paper presents a case study of the extensive soil improvement work carried out on a reclamation project on the shores of United Arab Emirates. The project consisted an area of approximately 480,000 m<sup>2</sup> for recreation purposes. Following the dredging work, approximately 6.8 million cubic meters underwent densification using the vibrocompaction method. The general aims of such analysis are to investigate the effectiveness of vibrocompaction as a method of soil improvement and appraise the selection of this method as the most appropriate soil treatment technique necessary for the adequate densification of the overall loose soil masses. The efficiency of the vibrocompaction technique to densify thick granular-based soil formations of considerable thickness and the benefits obtained, equated to other soil treatment methods, was assessed through a comprehensive post quality control program including field and laboratory post-compaction testing. Based on the analysis conducted it is concluded that soil strength of the reclaimed materials achieved a noteworthy improvement reaching comfortably the required degrees of densification. 展开更多
关键词 RECLAMATION dredging Manmade Islands COMPACTION Soil Improvement
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High-efficiency stabilization of dredged sediment using nano-modified and chemical-activated binary cement
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作者 Lei Lang Bing Chen Jiangshan Li 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第8期2117-2131,共15页
High-efficiency disposal of dredged sediment(DS)has become an imperative geo-environmental engineering issue due to the limited landfilling space and severe environmental burdens.This study firstly developed a novel h... High-efficiency disposal of dredged sediment(DS)has become an imperative geo-environmental engineering issue due to the limited landfilling space and severe environmental burdens.This study firstly developed a novel high-efficiency nano-modified and chemical-activated binary cement(NBC),which was composed of binary cement(BC)consisting ordinary Portland cement(OPC)and ground granulated blast-furnace slag(GGBS),chemical-activator and nano-modifier.The effects of chemical-activation and nano-modification on the strength development of BC-stabilized DS(BCDS),and the optimum mix of NBC were respectively achieved via a series of unconfined compressive strength and orthogonal tests.Then,the high-efficiency and economic applicability of NBC in DS stabilization were evaluated by comparing with OPC.Furthermore,the microstructure and mineral composition evolutions inside NBCstabilized DS(NDS)were explored by conducting X-ray diffraction(XRD)and scanning electron microscopy(SEM)tests.The results show that both chemical-activation and nano-modification could effectively improve the strength gain of BCDS,and compared with single chemical-activator and nanomodifier,the composite chemical-activators and nano-modifiers exhibited better performances.Based on BC with OPC/GGBS mass ratio of 1:1,both anhydrous sodium metasilicate/anhydrous sodium sulfate(SM/SS)and nano-SiO_(2)/nano-MgO(NS/NM)with mass ratio of 1:9 were respectively determined to be optimum chemical-activator and nano-modifier.The optimum mass ratio of BC,SM/SS and NS/NM was 20:2:1,i.e.the optimum mix of NBC.Compared with OPC,NBC exhibited higher stabilization efficiency and better economic applicability.The generation of calcium silicate hydrate(CSH),calcium aluminate hydrate(CAH)and ettringite contributed to the formation of dense cemented soil matrix inside NDS,and a conceptual micro-mechanism model characterizing the strength development under the coupling action of chemical-activation and nano-modification was proposed. 展开更多
关键词 Dredged sediment(DS) STABILIZATION Chemical-activation NANO-MODIFICATION Microstructure
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Mechanical properties of dredged soil reinforced by xanthan gum and fibers
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作者 Dianzhi Feng Bing Liang +4 位作者 Xingxing He Fu Yi Jianfei Xue Yong Wan Qiang Xue 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第8期2147-2157,共11页
Biopolymers have become popular in geotechnical engineering as they provide a carbon-neutral alternative for soil solidification.Xanthan gum(XG)and jute fiber(JF)were selected to solidify the Yellow River dredged soil... Biopolymers have become popular in geotechnical engineering as they provide a carbon-neutral alternative for soil solidification.Xanthan gum(XG)and jute fiber(JF)were selected to solidify the Yellow River dredged soil.The mechanical behavior of solidified dredged soil(SDS)was investigated using a series of uniaxial compression and splitting tension tests at different XG and JF contents and fiber lengths.The results indicate that on the 28th day,the unconfined compressive strength(UCS)values of SDS samples reached 2.83 MPa and splitting tensile strength(STS)of 0.763 MPa at an XG content of 1.5%.When the JF content was greater than 0.9%,the STS of the SDS samples decreased.This is because that the large fiber content weakened the cementation ability of XG.The addition of JF can significantly increase the strain at peak strength of SDS samples.There is a linear relationship between the UCS and STS of the dredged soils solidified by XG and JF.Microanalysis shows that the strength of SDS samples was improved mainly via the cementation of XG itself and the network structure formed by JF with soil particles.The dredged soil reinforced by XG and JF shows better mechanical performance and has great potential for application. 展开更多
关键词 Solidified dredged soil(SDS) Xanthan gum(XG) Jute fiber(JF) Mechanical properties
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