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The failure propagation of weakly stable sediment:A reason for the formation of high-velocity turbidity currents in submarine canyons
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作者 Yupeng REN Yi ZHANG +3 位作者 Guohui XU Xingbei XU Houjie WANG Zhiyuan CHEN 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2023年第1期100-117,共18页
The long-distance movement of turbidity currents in submarine canyons can transport large amounts of sediment to deep-sea plains.Previous studies show obvious differences in the turbidity current velocities derived fr... The long-distance movement of turbidity currents in submarine canyons can transport large amounts of sediment to deep-sea plains.Previous studies show obvious differences in the turbidity current velocities derived from the multiple cables damage events ranging from 5.9 to 28.0 m/s and those of field observations between 0.15 and 7.2 m/s.Therefore,questions remain regarding whether a turbid fluid in an undersea environment can flow through a submarine canyon for a long distance at a high speed.A new model based on weakly stable sediment is proposed(proposed failure propagation model for weakly stable sediments,WS S-PFP model for short)to explain the high-speed and long-range motion of turbidity currents in submarine canyons through the combination of laboratory tests and numerical analogs.The model is based on two mechanisms:1)the original turbidity current triggers the destabilization of the weakly stable sediment bed and promotes the destabilization and transport of the soft sediment in the downstream direction and 2)the excitation wave that forms when the original turbidity current moves into the canyon leads to the destabilization and transport of the weakly stable sediment in the downstream direction.The proposed model will provide dynamic process interpretation for the study of deep-sea deposition,pollutant transport,and optical cable damage. 展开更多
关键词 turbidity current excitation wave dense basal layer velocity WSS-PFP model
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Noninvasive Fetal Lung Maturity Prediction Based on Amniotic Fluid Turbidity Using Ultrasonic Histogram Measurement Function
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作者 Kensuke Matsumoto Kaoru Yamawaki +1 位作者 Kazufumi Haino Koji Nishijima 《Open Journal of Obstetrics and Gynecology》 CAS 2023年第1期26-36,共11页
Background: Amniotic fluid turbidity increases with fetal lung maturation due to vernix and lung surfactant micelles suspended in the amniotic fluid. This study focused on this phenomenon and evaluated the presence or... Background: Amniotic fluid turbidity increases with fetal lung maturation due to vernix and lung surfactant micelles suspended in the amniotic fluid. This study focused on this phenomenon and evaluated the presence or absence of respiratory distress syndrome (RDS)/transient tachypnea of the newborn (TTN) by quantitatively assessing the brightness of the amniotic fluid turbidity using a noninvasive ultrasound histogram measurement function. Methods: We included cases of singleton pregnancies managed at the Niigata University Medical and Dental Hospital between November 2020 and March 2022. Histograms of amniotic fluid turbidity were measured at the center of the amniotic fluid depth, avoiding the fetus, placenta, and umbilical cord, with the gain setting set to 0, and the average value was obtained after three measurements. Histograms of fetal urine in the bladder were measured similarly. The value obtained by subtracting the fetal bladder brightness value from the amniotic brightness value based on histogram measurements was used as the final amniotic fluid brightness value. Results: We included 118 cases (16 of RDS/TTN and 102 of control). The gestational age of delivery weeks was correlated with amniotic fluid brightness (Spearman’s rank correlation coefficient was 0.344;p = 0.00014). Amniotic fluid brightness values were significantly lower in the RDS/TTN group than in the control group (RDS/TTN: 16.2 ± 13.5, control: 26.3 ± 16.3;p = 0.020). The optimal cutoff value of amniotic fluid brightness to predict RDS/TTN was 20.3. For predicting RDS/TTN, the sensitivity, specificity, positive predictive value, and negative predictive value were 91.7%, 69.6%, 26.2%, and 94.1%, respectively. Conclusions: The quantitative value of the amniotic fluid brightness by histogram measurements may provide an easy and objective index for evaluating the presence or absence of RDS/TTN. 展开更多
关键词 Amniotic Fluid BRIGHTNESS Fetal Lung HISTOGRAM turbidity
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Impact of Untreated Sedimentation Tank Sludge Water Recycle on Water Quality During Treatment of Low Turbidity Water 被引量:1
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作者 Ronggang Xu Yongpeng Xu +3 位作者 Fuyi Cui Li He Dong Wang Qingfeng Su 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2015年第4期79-86,共8页
The overall purpose of this research is to examine the impact of untreated sedimentation tank sludge water( USTSW) recycle on water quality during treatment of low turbidity water in coagulation—sedimentation process... The overall purpose of this research is to examine the impact of untreated sedimentation tank sludge water( USTSW) recycle on water quality during treatment of low turbidity water in coagulation—sedimentation processes. 950 m L of raw water and different concentrations of 50 m L USTSW are injected into six 1 000 m L beakers without coagulant.The results indicate that USTSW characterized as accumulated suspended solids and organic matter has active ingredients,which possess the equivalent function of coagulant. The optimal blended water turbidity is in the range of 10-20 NTU,within which USTSW recycle achieves the highest save coagulant rate. The mechanism of strengthening coagulation effect when USTSW recycle mainly depends on the chemical effect and physical effect. What is more,through scanning electron microscopy( SEM),it is found that the floc structures with USTSW recycle are more compact than those without USTSW recycle. Besides,the water quality parameters of color,NH3-N,CODMn,UV254,total aluminum,total manganese when USTSW recycle is better than the raw water without recycle,indicating that USTSW recycle can improve water quality with strengthening coagulation effect. 展开更多
关键词 untreated sedimentation tank sludge water recycle low turbidity optimal blended water turbidity water quality
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Distribution of Turbidity and Fluorescence of SPM in Adjacent Waters of Taiwan Bank in Summer
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作者 胡毅 陈坚 和转 《Marine Science Bulletin》 CAS 2009年第2期45-54,共10页
The turbidity and fluorescence of suspended particulate matter (SPM) in the Taiwan Bank and adjacent waters were investigated during July-August, 2004, to examine the effects of the marine sediments re-suspension an... The turbidity and fluorescence of suspended particulate matter (SPM) in the Taiwan Bank and adjacent waters were investigated during July-August, 2004, to examine the effects of the marine sediments re-suspension and sedimentary processes on the turbidity and fluorescence distribution of SPM. The results show that the turbidity of SPM is affected by the re-suspension of marine sediment in the near shore and continental shelf outer fringe, but not obvious in the shoal. The enrichment of phytoplankton has some effects on the turbidity in the continental shelf outer fringe, but not evident in the near shore. This is helpful for better understanding the distribution of turbidity and fluorescence in the adjacent waters of Taiwan Bank. 展开更多
关键词 Taiwan Bank suspended Matter turbidity FLUORESCENCE
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A Study of Linke Turbidity Factor over Qena / Egypt
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作者 Sayed M. Elshazly 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1996年第4期519-532,共14页
Data on instantaneous atmospheric Linke turbidity factor TL (m) are reported for clear days at Qena/Egypt in the period from June 1992 to May 1993.TL(m) is determined using the values of irradiance of direct solar rad... Data on instantaneous atmospheric Linke turbidity factor TL (m) are reported for clear days at Qena/Egypt in the period from June 1992 to May 1993.TL(m) is determined using the values of irradiance of direct solar radiation (I),which are calculated from global (G) and diffuse (D) - solar radiation measurements.Monthly and seasonally variations of both diurnal and daily average values of TL (m) increases steadily in the direction of sunset in the months from June to December 1992 as well as Summer and Autumn seasons,while it falls generally in this direction for the months from January to March and Winter season.In April and May,TL (m) fluctuates obviously through the day hours,it is also shown that the average values of TL(m) are particularly large during Summer months compared to other months of the year.This behavior of TL(m) is discussed in view of the variations of some weather elements,which affect the content of water vapor and dust particle in the atmosphere of the study region.It seems t be of similar trends to that of other locations inside and outside Egypt.The virtual variation of TL(m) is eliminated by reducing its value to relative optical air mass m=2,according to Kasten formula.The resulting TL (2) is more representative for the content of dust particles and water vapor in the atmosphere. 展开更多
关键词 turbidity Linke turbidity factor Seasonal and diurnal variations Solar radiations components measurements AEROSOL
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Estimating Clear Sky Solar Radiation Using Linke and Angstrom Turbidity Coefficients in Romania
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作者 E. Eftimie 《Journal of Energy and Power Engineering》 2011年第1期29-41,共13页
The renewable systems design software and building energy simulation software for energy efficient buildings, use as a main input the solar radiation. The implementation of such systems in the urban environment requir... The renewable systems design software and building energy simulation software for energy efficient buildings, use as a main input the solar radiation. The implementation of such systems in the urban environment requires accurate meteorological data for the interest area. The existence of a small number of weather stations that to offer data with regard to solar radiation as well as the limited access to these, makes necessary the conceiving of some more accurate estimation mathematical models for all climatological parameters. The present paper proposes a study of the Linke and AngstrOm turbidity coefficients, for Brasov urban area, with the purpose of a more accurate solar radiation simulation. Models performance is analyzed using the root mean square error (RMSE), the mean bias error (MBE), the mean percentage error (MPE) and the t-statistic. 展开更多
关键词 Linke turbidity AngstrOm turbidity total radiation diffuse radiation MBE MPE RMSE t-statistic.
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CFD simulation on the generation of turbidites in deepwater areas: a case study of turbidity current processes in Qiongdongnan Basin, northern South China Sea 被引量:5
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作者 JIANG Tao ZHANG Yingzhao +6 位作者 TANG Sulin ZHANG Daojun ZUO Qianmei LIN Weiren WANG Yahui SUN Hui WANG Bo 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2014年第12期127-137,共11页
Turbidity currents represent a major agent for sediment transport in lakes, seas and oceans. In particu-lar, they formulate the most significant clastic accumulations in the deep sea, which become many of the world's... Turbidity currents represent a major agent for sediment transport in lakes, seas and oceans. In particu-lar, they formulate the most significant clastic accumulations in the deep sea, which become many of the world's most important hydrocarbon reservoirs. Several boreholes in the Qiongdongnan Basin, the north-western South China Sea, have recently revealed turbidity current deposits as significant hydrocarbon res-ervoirs. However, there are some arguments for the potential provenances. To solve this problem, it is es-sential to delineate their sedimentary processes as well as to evaluate their qualities as reservoir. Numerical simulations have been developed rapidly over the last several years, offering insights into turbidity current behaviors, as geologically significant turbidity currents are difficult to directly investigate due to their large scale and often destructive nature. Combined with the interpretation of the turbidity system based on high-resolution 3D seismic data, the paleotophography is acquired via a back-stripping seismic profile integrated with a borehole, i.e., Well A, in the western Qiongdongnan Basin; then a numerical model is built on the basis of this back-stripped profile. After defining the various turbidity current initial boundary conditions, includ-ing grain size, velocity and sediment concentration, the structures and behaviors of turbidity currents are investigated via numerical simulation software ANSYS FLUENT. Finally, the simulated turbidity deposits are compared with the interpreted sedimentary bodies based on 3D seismic data and the potential provenances of the revealed turbidites by Well A are discussed in details. The simulation results indicate that a sedimen-tary body develops far away from its source with an average grain size of 0.1 mm, i.e., sand-size sediment. Taking into account the location and orientation of the simulated seismic line, the consistence between normal forward simulation results and the revealed cores in Well A indicates that the turbidites should have been transported from Vietnam instead of Hainan Island. This interpretation has also been verified by the planar maps of sedimentary systems based on integration of boreholes and seismic data. The identification of the turbidity provenance will benefit the evaluation of extensively distributed submarine fans for hydro-carbon exploration in the deepwater areas. 展开更多
关键词 turbidity current CFD simulation 3D seismic interpretation sedimentary process
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Pilot scale treatment of low turbidity water using compound bioflocculant and polymerized aluminium ferrum chloride 被引量:7
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作者 马放 孟路 +2 位作者 庞长泷 金超 姚杰 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2009年第3期441-444,共4页
To investigate the application of compound bioflocculant (CBF) in drinking water treatment at pilot plant, CBF and polymerized aluminium ferrum chloride (PAFC) coagulant were used to treat raw water taken from Lon... To investigate the application of compound bioflocculant (CBF) in drinking water treatment at pilot plant, CBF and polymerized aluminium ferrum chloride (PAFC) coagulant were used to treat raw water taken from Longhupao Reservoir in Heilongjiang Province for the removal of turbidity, COl), UV254 and residual Al. Coagulation test shows that the coagulation enhanced by CBF and PAFC exhibits more effective performance than that enhanced by the individual of them, and the total combination dosage is lower than that of the individual. The residual Al from PAFC can be removed efficiently by CBF. The removal efficiency of turbidity reaches 76.6% by combining CBF of 2 mg/L and PAFC of 15 mg/L, COl) is decreased from 3.80 mg/L to 1.62 mg/ L, and the concentration of residual Al is only 0. 033 mg/L in the product water. It can be speculated that adsorption-bridging and sweep-coagulation processes are predominant in the flocculation process by the combination of CBF and PAFC. 展开更多
关键词 low turbidity water compound bioflocculant PAFC COAGULATION
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CO_2 flux and seasonal variability in the turbidity maximum zone and surrounding area in the Changjiang River estuary 被引量:4
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作者 李学刚 宋金明 +3 位作者 袁华茂 李宁 段丽琴 曲宝晓 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2015年第1期222-232,共11页
The turbidity maximum zone(TMZ) is one of the most important regions in an estuary.However,the high concentration of suspended material makes it difficult to measure the partial pressure of CO_2(pCO_2) in these region... The turbidity maximum zone(TMZ) is one of the most important regions in an estuary.However,the high concentration of suspended material makes it difficult to measure the partial pressure of CO_2(pCO_2) in these regions.Therefore,very little data is available on the pCO_2 levels in TMZs.To relatively accurately evaluate the CO_2 flux in an example estuary,we studied the TMZ and surrounding area in the Changjiang(Yangtze) River estuary.From seasonal cruises during February,August,November 2010,and May 2012,the pCO_2 in the TMZ and surrounding area was calculated from pH and total alkalinity(TA)measured in situ,from which the CO_2 flux was calculated.Overall,the TMZ and surrounding area acted as a source of atmosphere CO_2 in February and November,and as a sink in May and August.The average FCO_2was-9,-16,5,and 5 mmol/(m^2·d) in May,August,November,and February,respectively.The TMZ's role as a source or sink of atmosphere CO_2 was quite different to the outer estuary.In the TMZ and surrounding area,suspended matter,phytoplankton,and pH were the main factors controlling the FCO_2,but here the influence of temperature,salinity,and total alkalinity on the FCO_2 was weak.Organic carbon decomposition in suspended matter was the main reason for the region acting as a CO_2 source in winter,and phytoplankton production was the main reason the region was a CO_2 sink in summer. 展开更多
关键词 CO2 flux seasonal variability turbidity maximum zone Changjiang River estuary
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Enhanced treatment of water with low turbidity:Combined effects of permanganate, PAM and recycled sludge 被引量:4
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作者 孙丽华 吕谋 +3 位作者 杨艳玲 林建禄 周玲玲 李圭白 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2009年第6期863-868,共6页
The effectiveness of enhancing treatment of water with low turbidity through combined effects of permanganate oxidation, PAM aiding coagulation and sludge recycling was investigated through continuous bench scale stud... The effectiveness of enhancing treatment of water with low turbidity through combined effects of permanganate oxidation, PAM aiding coagulation and sludge recycling was investigated through continuous bench scale studies. In comparing with ferric chloride coagulation, only recycling sedimentation sludge was ineffective in enhancing treatment of water with low turbidity. PAM with recycled sludge showed positive effects, and the additional permanganate dosing exhibited the best potential of favoring coagulation, which leaded to much lower effluent turbidity and CODMa. Additionally, it was observed that the optimal permanganate dosage was 0. 4 mg/ L and the higher permanganate dosage exhibited inhibiting effects for pollutants removal. SEM analysis indicated that the floes were loosely formed and the particle diameter was critically low for ferric chloride coagulation process. Comparatively, the addition of PAM and permanganate with recycled sludge facilitated the aggregation of tinny particles onto compact PAM polymer chains, therefore contributing to the formation of compact floes with high particle diameter. The combined employment of recycled sludge, PAM and permanganate showed the best potential of favoring coagulation, mainly through synergistic effects between seeding, polymer bridging and increasing effective collision in mechanism. Additionally, the variation of Fe and Mn concentration after recycling and sedimentating units was studied for the processes, and the main species was also investigated for elements Fe and Mn. Sludge recycling and permanganate addition did not increase Fe and Mn concentration in the sedimented water. 展开更多
关键词 water with low turbidity PERMANGANATE recycled sludge SEEDING polymer bridging
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The vertical attenuation of irradiance as a function of turbidity: a case of the Huanghai (Yellow) Sea in spring 被引量:2
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作者 LIN Shaoying ZOU Tao +1 位作者 GAO Huiwang GUO Xinyu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2009年第5期66-75,共10页
The planar photosynthetically available radiation (PAR), turbidity and concentration of chlorophyll a (chl a), were measured at 26 stations in the Huanghai (Yellow) Sea during a cruise of China SOLAS from 19 to ... The planar photosynthetically available radiation (PAR), turbidity and concentration of chlorophyll a (chl a), were measured at 26 stations in the Huanghai (Yellow) Sea during a cruise of China SOLAS from 19 to 27 March 2005. Due to low chl a (〈0.35 mg · m^-3 ) in upper layers (above 5 m), suspended particulate matter became the major factor that influenced the turbidity in early spring. The calculated vertical diffuse attenuation coefficient of PAR, K PAR , varied with water depths with a maximum value in the upper 5 m layer. The mean K PAR in survey area was 0.277 ± 0.07 m^-1 that is considerably higher than most of the other case 2 waters. Within the survey area, K PAR also showed distinct regional characteristics, corresponding to the distribution of turbidity. Based on measurements, the relationship between K PAR and turbidity as well as chl a was established. It was suggested that suspended particulate matter plays an important role in light attenuation in the Huanghai (Yellow) Sea in spring. 展开更多
关键词 Photosynthetically available radiation Diffuse attenuation coefficient turbidity Chlorophyll a the Huanghai (Yellow) Sea
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Characteristics and generation mechanism of turbidity maximum in the Changjiang Estuary 被引量:2
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作者 Pan Ding’an Shen Huanting Mao Zhichang and Liu Xincheng (1. State Key Lab of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China) 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2000年第1期47-57,共11页
Sediment convergence and resuspension are the two major mechanisms in forming turbidity maximum (TM) in the Changjiang Estuary. Sediment convergence is mainly controlled by the interaction between runoff and tidal cu... Sediment convergence and resuspension are the two major mechanisms in forming turbidity maximum (TM) in the Changjiang Estuary. Sediment convergence is mainly controlled by the interaction between runoff and tidal current, the mixing of freshwater and salt water, the former forming tidal TM, whereas the latter forming brackish TM. The TM in the Changjiang Estuary is characterized by a combination of tidal TM and brackish TM, which varies temporally and spatially. 展开更多
关键词 Changjiang Estuary turbidity maximum sediment convergence RESUSPENSION
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Architecture mode, sedimentary evolution and controlling factors of deepwater turbidity channels: A case study of the M Oilfield in West Africa 被引量:2
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作者 Wen-Biao Zhang Tai-Zhong Duan +3 位作者 Zhi-Qiang Liu Yan-Feng Liu Lei Zhao Rui Xu 《Petroleum Science》 SCIE CAS CSCD 2017年第3期493-506,共14页
Turbidity channels have been considered as one of the important types of deepwater reservoir, and the study of their architecture plays a key role in efficient development of an oil field. To better understand the res... Turbidity channels have been considered as one of the important types of deepwater reservoir, and the study of their architecture plays a key role in efficient development of an oil field. To better understand the reservoir architecture of the lower Congo Basin M oilfield, semiquantitative–quantitative study on turbidity channel depositional architecture patterns in the middle to lower slopes was conducted with the aid of abundant high quality materials(core, outcrop, logging and seismic data),employing seismic stratigraphy, seismic sedimentology and sedimentary petrography methods. Then, its sedimentary evolution was analyzed accordingly. The results indicated that in the study area, grade 3 to grade 5 architecture units were single channel, complex channel and channel systems, respectively. Single channel sinuosity is negatively correlated with the slope, as internal grains became finer and thickness became thinner from bottom to top, axis to edge. The migration type of a single channel within one complex channel can be lateral migration and along paleocurrent migration horizontally, and lateral,indented and swing stacking in section view. Based on external morphological characteristics and boundaries,channel systems are comprised of a weakly confining type and a non-confining type. The O73 channel system can be divided into four complex channels named S1–S4, from bottom to top, with gradually less incision and more accretion. The study in this article will promote deeper understanding of turbidity channel theory, guide 3D geological modeling in reservoir development and contribute to efficient development of such reservoirs. 展开更多
关键词 Reservoir architecture turbidity channelSedimentary evolution Deep water Shallow seismicControlling factors
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A Novel Water Pretreatment Approach for Turbidity Removal Using Date Seeds and Pollen Sheath 被引量:2
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作者 Mukheled Al-Sameraiy 《Journal of Water Resource and Protection》 2012年第2期79-92,共14页
Turbidity is a characteristic related to the concentration of suspended solids particles in water and has been adopted as an easy and reasonably accurate measure of overall water quality. The most widely applied water... Turbidity is a characteristic related to the concentration of suspended solids particles in water and has been adopted as an easy and reasonably accurate measure of overall water quality. The most widely applied water treatment processes, a combination of some or all of coagulation, flocculation, sedimentation and filtration to reduce or eliminate turbidity and improve water quality. In this research, proposed approach was adopted on the basis of applying two sequent treatments that used coagulation, flocculation and sedimentation processes under certain operating conditions of mixing speed, mixing time and settling time for each treatment. The environmentally friendly natural coagulants of date seeds (DS) or pollen sheath (PS) from local Iraqi palm was used in the first treatment and alum was used in the second treatment at their predetermined optimum doses to treat low ( NTU), medium ( NTU) and high ( NTU) ben- tonite synthetic turbid water. Experimental results clearly show that the proposed approach was superior in perform- ance in terms of residual turbidity compared with conventional approach using both of (DS) and (PS) natural coagulants in which it achieved a significant reduction in turbidity to less of 5 NTU that meeting WHO drinking water guidelines for all tested synthetic turbid water. Moreover, in some cases, it produced excellent water quality having residual tur- bidity less of 0.1 NTU. In addition to decrease the settling time to 30 minutes and minimize risks of alum dose required to 60%. These viable advantages are significant to current practices in advanced water treatment technologies such as reverse osmosis in cost, energy, effectiveness, safety and maintenance. So, it is recommended to consider proposed approach in this research work to be a novel pretreatment approach in advanced water treatment. 展开更多
关键词 Coagulation FLOCCULATION DATE SEEDS POLLEN SHEATH turbidity Removal Bentonite
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Turbidity analysis using visible and near-infrared light images 被引量:2
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作者 ZHU Yuanyang ZHAO Wenzhu +1 位作者 LIU Sheng GAO Hongwen 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2021年第1期27-35,共9页
The conventional photoelectric detection system requires complex circuitry and spectroscopic systems as well as specialized personnel for its operation.To replace such a system,a method of measuring turbidity using a ... The conventional photoelectric detection system requires complex circuitry and spectroscopic systems as well as specialized personnel for its operation.To replace such a system,a method of measuring turbidity using a camera is proposed by combining the imaging characteristics of a digital camera and the high-speed information processing capability of a computer.Two turbidity measurement devices based on visible and near-infrared(NIR)light cameras and a light source driving circuit with constant light intensity were designed.The RGB data in the turbidity images were acquired using a self-developed image processing software and converted to the CIE Lab color space.Based on the relationship between the luminance,chromatic aberration,and turbidity,the turbidity detection models for luminance and chromatic aberration of visible and NIR light devices exhibiting values from 0-1000 NTU,less than 100 NTU,and more than 100 NTU were established.By comparing and analyzing the proposed models,the two measurement models with the best all-around performance were selected and fused to generate new measurement models.The experimental results prove that the correlation between the three models and the commercial turbidity meter measurements exhibite a significance value higher than 0.999.The error of the fusion model is within 1.05%,with a mean square error of 1.14.The visible light device has less error at low turbidity measurements and is less influenced by the color of the image.The NIR light device is more stable and accurate at full range and high turbidity measurements and is therefore more suitable for such measurements. 展开更多
关键词 image processing water quality turbidity measurement near-infrared image color space conversion
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C haracteristics of turbulent kinetic energy dissipation rate and turbidity near the coast of East China Sea 被引量:1
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作者 张艳伟 许惠平 +2 位作者 覃如府 徐昌伟 范代读 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2016年第5期1134-1142,共9页
The East China Sea(ECS) has a high suspended-sediment concentration because of the influence of the Changjiang River,indicated by high turbidity in the water.Considering the islands off the coast and the complex topog... The East China Sea(ECS) has a high suspended-sediment concentration because of the influence of the Changjiang River,indicated by high turbidity in the water.Considering the islands off the coast and the complex topography,and the strong influence of tides and wind,the coast off the ECS is a typical region with strong oceanic mixing processes.The changes in the dynamic processes near the bottom play an important role in the control of water turbidity.The turbulent kinetic energy dissipation rate(ε) is a parameter that shows the strength of ocean mixing.This is estimated based on a structure method using current velocity that is measured by a high-frequency Acoustic Doppler Current Profiler(ADCP) from a seafloor observatory in the ECS.The results indicate strong ocean mixing processes with a mean e value of 5.7×10^(-5) W/kg and distinct tidal variations in the dissipation rate.Conversely,the variation of the water turbidity leads to changes in the water dynamical structure near the bottom.Comparing the dissipation rate with the turbidity near the bottom boundary layer,we find that the high turbidity mimics strong ocean mixing. 展开更多
关键词 turbulent kinetic energy DISSIPATION rate turbidity TIDES NEAR BOTTOM boundary East China Sea
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A new method for the estimation of fine-sediment resuspension ratios in estuaries-taking the turbidity maximum zone of the Changjiang(Yangtze) estuary as an example 被引量:1
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作者 沈志良 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2012年第5期791-795,共5页
Based on the principle of conservative matter removal in estuary,a new method is proposed for estimating the ratio of sediment resuspension in estuaries with fine suspended sediments in the turbidity maximum zone(TMZ)... Based on the principle of conservative matter removal in estuary,a new method is proposed for estimating the ratio of sediment resuspension in estuaries with fine suspended sediments in the turbidity maximum zone(TMZ) of the Changjiang(Yangtze) estuary during 2005.Results show that there was a range of 18.7%±27.9% to 73.9%±22.5% per annum of total suspended particulate matter(SPM),with an average of 49.2%.Nearly half of the particulate matter in the TMZ originates from sediment resuspension.This indicates that sediment resuspension is one of the major mechanisms involved in formation of the TMZ.Compared with traditional method for calculating these ratios in the estuary,this new method evaluates the dynamic variation of SPM content carried by river runoff from the river mouth to the ocean.The new method produced more reliable results than the traditional one and could produce a better estimation of resuspension flux for particulate matter in estuaries. 展开更多
关键词 sediment suspended particulate matter resuspension ratio estimate method turbidity maximumzone Changjiang (Yangtze) estuary
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Turbidity maximum formation and its seasonal variations in the Zhujiang(Pearl River)Estuary,southern China 被引量:5
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作者 LIU Runqi WANG Yaping +2 位作者 GAO Jianhua WU Ziyin GUAN Weibing 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2016年第8期22-31,共10页
Real-time observations in the field and numerical simulations(with Delft3D) were combined to study the formation, distribution and the relevant influencing factors of turbidity maximum(TM) in the Zhujiang(Pearl R... Real-time observations in the field and numerical simulations(with Delft3D) were combined to study the formation, distribution and the relevant influencing factors of turbidity maximum(TM) in the Zhujiang(Pearl River) Estuary(ZE). The spatial distribution pattern of the TM varies with the longitudinal distributions of salinity and suspended sediment concentration(SSC). The SSC is enhanced and the TM is intensified during dry seasons,whereas the center of the TM moves upstream by a distance of 10 km during wet seasons. The formation of the TM is influenced by a complex combination of numerous factors, including tides, river discharges and topography, wherein sediment resuspension and vertical circulation dominate the formations and variability of the TM. 展开更多
关键词 sediment resuspension vertical circulation turbidity maximum Delft3D Zhujiang(Pearl River) Estuary
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Heavy metals in suspended matters during a tidal cycle in the turbidity maximum around the Changjiang(Yangtze) Estuary 被引量:1
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作者 ZHANG Huaijing ZHAI Shikui +2 位作者 ZHANG Aibin ZHOU Yonghua YU Zenghui 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2015年第10期36-45,共10页
In order to discuss the content distributions and fluxes of heavy metals in suspended matters during a tidal cycle in the turbidity maximum around the Changjiang (Yangtze) Estuary, the contents of heavy metals (Zn,... In order to discuss the content distributions and fluxes of heavy metals in suspended matters during a tidal cycle in the turbidity maximum around the Changjiang (Yangtze) Estuary, the contents of heavy metals (Zn, Pb, Cd, Co and Ni) have been analyzed. During a tidal cycle, the average contents of heavy metals are in the order of Zn〉Ni〉Pb〉Co〉〉Cd. The average contents in ebb tide are generally higher than that in flood tide. However, at the inshore Sta. 11, influenced by the contamination from the nearby waste treatment plant, the average contents of Zn and Ni in flood tide are higher than those in ebb fide and at the offshore Sta. 10, the content of Cd in flood tide higher than that in ebb tide due to marine-derived materials. The five heavy metals, mainly terrigenous, are transported towards east-northeast, and settle down with suspended matters in the area between Sta. 11 and Sta. 10. Influenced by marine-derived materials, the flux value of Cd does not alter significantly with obviously changing in flux direction towards northwest. The source of heavy metals, the salinity of water and the concentration of suspended matters are the main factors controlling the content distributions of heavy metals during a tidal cycle. There is a positive correlation between the contents of heavy metals (Zn, Pb, Co and Ni) and the salinity of water, while the opposite correlation between the contents and the concentrations of suspended matters. Because of marine-derived materials, the content of Cd is not correlated with the concentration of suspended matters and the salinity of water. 展开更多
关键词 Changjiang (Yangtze) Estuary turbidity maximum zone tidal cycle suspended matters content ofheavy metal flux of heavy metal
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Features and Origin of Turbidity Current Sediment Waves in the Huatung Basin off the Eastern Taiwan Island 被引量:1
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作者 LIU Jie SUN Meijing +1 位作者 GAO Hongfang LI Xuejie 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2019年第4期1088-1096,共9页
Based on numerous high-resolution seismic profiles,sediment waves and their distribution,morphological characteristics,internal structure,and potential origins were revealed in the eastern waters of Taiwan.The sedimen... Based on numerous high-resolution seismic profiles,sediment waves and their distribution,morphological characteristics,internal structure,and potential origins were revealed in the eastern waters of Taiwan.The sediment waves are located at the junction between the Taitung Canyon and other canyons in the slope.The wave length and the wave height of a single waveform ranged from 0.8 to 7.2 km and from 18 to 75 m,respectively(NE-SW direction).Sediment waves,located inside the bend of the Taitung Canyon,were characterized by an upward migration and showed mass transport deposits(MTDs)at the bottom,while the inner curve of the bend was subdivided into lower and upper wavy transition units.The sediment waves on the outer curve of the bend were characterized by vertical accumulation,and there was no mass flow deposit at the bottom.According to the geometry of the sediment waves,the calculated flow thicknesses across the entire wave field ranged from 196 to 356 m,and the current velocity ranged from 15 to 21 cm/s.The morphological characteristics,the internal structure,and the distribution of sediment waves,as well as the numerical calculations,evidenced that these sediment waves had formed by turbidity currents.The development of the sediment wave field in eastern Taiwan was found to be similar to that in southwestern Taiwan.It was the sedimentary response of the tectonic movement between 3 and^1 Ma which created the sedimentary systems where gravity flow processes predominated.Turbidity current sediments settled in the place of less topographical constraints or overflowed in the bend section of the Taitung Canyon,which resulted in the formation of sediment wave fields. 展开更多
关键词 Huatung Basin Taitung Canyon sediment wave turbidity current formation mechanism
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