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Experimental Investigation on the Shape and Depth of Local Scour Hole Downstream of the Release Structure 认领
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作者 Vouchleang Hong Genguang Zhang +1 位作者 Xinqiang Wang Anbin Li 《世界工程和技术(英文)》 2020年第1期104-120,共17页
Local scour downstream of the release structure is a critical problem to the safe and stable operation of water resources and hydropower engineering. In order to investigate the shape and depth of the scour hole under... Local scour downstream of the release structure is a critical problem to the safe and stable operation of water resources and hydropower engineering. In order to investigate the shape and depth of the scour hole under the equilibrium state of erosion and deposition downstream of an apron, a group of 16 experiments from the hydraulic similarity model test of Dangka Hydropower Station?was conducted with the non-cohesive sediment of different median particle sizes under different flow rates in this study. The control variable method was?to?study the influence of the flow rate and sediment size on the shape of the scour hole to define the number of experiment times of each test group. The results showed that the plane shape of the scour hole was irregular ellipse or semi-ellipse. The depth and size of the scour hole increased with the increase of the flow rate, and decreased with the increase of the sediment size;?the downstream longitudinal slope ratio of the scour hole increased with the increase of the sediment size. The coefficients of the upstream and downstream slope ratio of the local scour hole were 1/2 to 1/6 and about 1/10, respectively. 展开更多
关键词 LOCAL SCOUR DOWNSTREAM Noncohesive SEDIMENT Bed SEDIMENT Size FLOW Rate FLOW Pattern Dangka HYDROPOWER Station
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论浅水湖泊中的水固交错带与科学清淤规划——以雄安新区白洋淀为例 认领
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作者 王东升 门彬 张美一 《环境科学学报》 CAS CSCD 北大核心 2020年第5期1550-1559,共10页
本文从雄安新区白洋淀科学清淤规划的重要性入手,提出水固交错带这一新型生态交错带研究的理念.重点关注由于沉积物形成过程和结构不同导致的污染物在水相、固相和气相及在水⁃固界面和水⁃气界面等区域的地球化学循环过程与机制的差异,... 本文从雄安新区白洋淀科学清淤规划的重要性入手,提出水固交错带这一新型生态交错带研究的理念.重点关注由于沉积物形成过程和结构不同导致的污染物在水相、固相和气相及在水⁃固界面和水⁃气界面等区域的地球化学循环过程与机制的差异,以及与其对应的特异性水生态和底栖生态修复理念与设计.基于这一理念,结合白洋淀内源污染治理的需求,进一步提出了“基于弹性机制的生态空间重构”的工作设想.以此抛砖引玉,深入探讨沉积物-水微界面过程机制,以及相应的特殊宏观生态效应与污染控制,推动环境水质学领域的研究与发展. 展开更多
关键词 沉积物 生态交错带 水陆交错带 水固交错带 白洋淀 科学清淤
Effect of intermittent aeration mode on nitrogen concentration in the water column and sediment pore water of aquaculture ponds 认领
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作者 Dantong Zhu Xiangju Cheng +1 位作者 David J.Sample Mohammad Nayeb Yazdi 《环境科学学报:英文版》 SCIE EI CAS CSCD 2020年第4期331-342,共12页
Nitrogen in pond sediments is a major water quality concern and can impact the productivity of aquaculture.Dissolved oxygen is an important factor for improving water quality and boosting fish growth in aquaculture po... Nitrogen in pond sediments is a major water quality concern and can impact the productivity of aquaculture.Dissolved oxygen is an important factor for improving water quality and boosting fish growth in aquaculture ponds,and plays an important role in the conversion of ammonium-nitrogen(NH4-N)to nitrite-nitrogen(NO2--N)and eventually nitrate-nitrogen(NO3--N).A central goal of the study was to identify the best aeration method and strategy for improving water quality in aquaculture ponds.We conducted an experiment with six tanks,each with a different aeration mode to simulate the behavior of aquaculture ponds.The results show that a 36 hr aeration interval(Tc=36 hr:36 hr)and no aeration resulted in high concentrations of NH4-N in the water column.Using a 12 hr interval time(Tc=12 hr:12 hr)resulted in higher NO2--N and NO3--N concentrations than any other aeration mode.Results from an 8 hr interval time(Tc=8 hr:8 hr)and 24 hr interval time(Tc=24 hr:24 hr)were comparable with those of continuous aeration,and had the benefit of being in use for only half of the time,consequently reducing energy consumption. 展开更多
关键词 Intermittent aeration NITROGEN Water column Sediment resuspension and release SEDIMENT Sediment pore water
世界大河水沙通量变化趋势研究 认领
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作者 李莉 倪晋仁 +8 位作者 常方 岳遥 Natalia Frolova Dmitry Magritsky Alistair GLBorthwick Philippe Ciais 王易初 郑春苗 Desmond E.Walling 《科学通报:英文版》 SCIE EI CSCD 2020年第1期62-69,M0004共9页
河流水沙运动是地球化学循环的重要驱动力.本研究基于全球变化背景下的长序列水沙资料,对4307条世界大河(流域面积≥1000 km~2)水-沙通量的9种变化趋势及其成因进行了系统研究.结果表明,全球24%的大河呈现显著的径流变化,但年入海通量... 河流水沙运动是地球化学循环的重要驱动力.本研究基于全球变化背景下的长序列水沙资料,对4307条世界大河(流域面积≥1000 km~2)水-沙通量的9种变化趋势及其成因进行了系统研究.结果表明,全球24%的大河呈现显著的径流变化,但年入海通量基本保持稳定;40%的大河呈现显著的泥沙通量变化,年入海通量下降20.8%;其中,亚洲大型河流的水沙通量下降趋势及南美亚马逊河的悬移质浓度上升趋势尤为突出.总体上,71%的世界大河径流变化与降水密切相关,而泥沙通量变化受大坝运行和灌溉等人类活动影响较大. 展开更多
关键词 Water and SEDIMENT Global TREND Co-varying pattern CAUSE Large river
Rare Earth Elements in the Water Column of Sungai Balok, Pahang, Malaysia as Monsoon Event Proxies 认领
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作者 Zolhizir Daud Che Abd Rahim Mohamed 《环境保护(英文)》 2020年第5期421-440,共20页
Sampling of surface water at seven stations along the Sungai Balok, Pahang was conducted from 2013 to 2015 to investigate the distribution of dissolved rare earth elements (REE) in river systems. The whole concentrati... Sampling of surface water at seven stations along the Sungai Balok, Pahang was conducted from 2013 to 2015 to investigate the distribution of dissolved rare earth elements (REE) in river systems. The whole concentration of ΣREE in the dissolved phase recorded during this study ranged from 368 to 9121 pmol?L?1 with a mean of 2328 ± 1442 pmol?L?1 that was dominantly influenced by the concentration of Ce ranging from 84 to 3237 pmol?L?1. Similarly, the large ranged value of La/YbN (0.69 - 11.57) might be due to the fluctuating rainfall events during samplings as well as input from lithogenic sources that suggests the influence of monsoon events. The highly significant statistical correlation of Al and Fe (R2 = 0.65;p < 0.01) also suggests the resuspension and mixing of REEs in the water column. However, the lower ratio of Y/Ho < 55 might be due to the large volume of freshwater input especially during the Northeast monsoon (November to March). Therefore, the highest inventories of Ce were during 15th January 2014 and 1st November 2014 with 586.5 pmol?cm?2 and 643.4 pmol?cm?2, accordingly. Subsequently, results showed an increasing flux of Ce occurring in the dissolved phase from November 2013 to January 2014 and November 2014 to January 2015, with 39.14 nmol?cm?2?yr?1 and 59.78 nmol?cm?2?yr?1, respectively. 展开更多
关键词 RAINFALL Sediment Water COLUMN MONSOON Dissolved Phase
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Impact of Phenanthrene on Denitrification Activity and Transcription of Related Functional Genes in Estuarine and Marine Sediments 认领
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作者 SUN Pengfei BAI Jie +4 位作者 LI Kuiran ZHAO Yangguo TIAN Weijun BAI Xiaoyan TIAN Yanzhao 《中国海洋大学学报:英文版》 SCIE CAS CSCD 2020年第1期124-134,共11页
The effects of phenanthrene(Phe) on the denitrification activity and denitrifying genes(nar G, nir S and nos Z) were evaluated by dose-response experiments in sediments of Dagu River Estuary(DRE) and Jiaozhou Bay(JZB)... The effects of phenanthrene(Phe) on the denitrification activity and denitrifying genes(nar G, nir S and nos Z) were evaluated by dose-response experiments in sediments of Dagu River Estuary(DRE) and Jiaozhou Bay(JZB). The results showed that potential denitrification activity(PDA), N2O, NO3- and NO2- reduction rates of both areas were inhibited with an increase of Phe concentrations. The PDA, N2O, NO3- and NO2- reduction rates of both areas was highest and lowest in the control(DRE: 0.453, 0.427, 7.439 and 3.222 mg Nkg-1 h-1, JZB: 0.592, 0.555, 8.470 and 3.793 mg Nkg-1 h-1) and highest Phe amended treatments(DRE: 0.069, 0.001, 4.486, and 1.563 mg Nkg-1 h-1;JZB: 0.114, 0.024, 5.527 and 2.200 mg Nkg-1 h-1). The inhibition rate of PDA was highest, follow by NO2-reduction and then NO3- reduction. Moreover, with the increasing of Phe concentrations, total bacteria count and the abundance of denitrifying genes were decreased. And N2O accumulation was promoted with the addition of Phe for both areas. Based on the comparison of EC50 values, denitrifiers harboring three genes were more sensitive to Phe than PDA, and denitrifiers harboring nir S gene were more sensitive, followed by nos Z gene, and then nar G gene. Furthermore, according to correlation analysis, the relative abundance of denitrifying genes was much more positively correlated with PDA, NO3- and NO2-reduction than total bacteria count. In addition, the denitrification activity and total bacteria count in JZB were more inhibited than that of DRE. This study is useful for understanding the impact of Phe pollution on denitrification in estuary and marine sediments, with profound implications for the management of aquatic ecosystems regarding eutrophication(N-removal) and greenhouse effect. 展开更多
关键词 PHENANTHRENE effect DENITRIFICATION denitrifying GENES ESTUARINE SEDIMENT marine SEDIMENT
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长江口冲淤交替及变化趋势 认领
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作者 朱博渊 李义天 +4 位作者 岳遥 杨云平 梁恩航 张春财 BORTHWICK Alistair G.L. 《地理学报:英文版》 SCIE CSCD 2020年第1期145-163,共19页
The morphological changing trend of the Yangtze Estuary,the largest estuary of Asia,has become a focus of research in recent years.Based on a long series of topographic data from 1950 to 2015,this paper studied the er... The morphological changing trend of the Yangtze Estuary,the largest estuary of Asia,has become a focus of research in recent years.Based on a long series of topographic data from 1950 to 2015,this paper studied the erosion-deposition pattern of the entire Yangtze Estuary.An alternation between erosion and deposition was found during the past 65 years,which was in correspondence to the alternation between flood and dry periods identified by multi-year average duration days of high-level water flow(defined as discharge≥60,000 m 3/s,namely,D≥60,000)from the Yangtze River Basin.A quantitative relationship was further developed between the erosional/depositional rate of the Yangtze Estuary and the interpreting variables of yearly water discharge,D≥60,000 and yearly river sediment load,with contributing rates of 1%,59%and 40%,respectively.Mechanism behind the alternate erosion and deposition pattern was analyzed by examining residual water surface slope and the corresponding capacity of sediment transport in flood and dry periods.In flood periods,a larger discharge results in steeper slope of residual water level which permits a greater capacity of sediment transport.Therefore,more bed materials can be washed to the sea,leading to erosion of the estuary.In contrast,flatter slope of residual water level occurs in dry periods,and deposition dominates the estuarine area due to the decreased capacity of sediment transport and the increased backwater effect of flood-tide.Coastal dynamics and estuarine engineering projects alter the local morphological changes,but slightly affect the total erosional/depositional rate of the whole estuarine region.Heavy sedimentation within the Yangtze Estuary after the impoundment of the Three Gorges Dam can be attributed to the reduced occurrence frequency of flood years due to water regulation by the dam,and largely(at least 36%-52%)sourced from the sea.Deposition is still possible to occur in the Yangtze Estuary in the future,because the multi-year average D≥60,000 is unlikely to 展开更多
关键词 YANGTZE ESTUARY EROSION and deposition ALTERNATION total sediment load evolutional TREND
Ecological and Human Health Risk Assessment of Toxic Metals in Water, Sediment and Fish from Lower Usuma Dam, Abuja, Nigeria 认领
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作者 R. Wuana C. Ogbodo +1 位作者 A. U. Itodo I. S. Eneji 《地球科学和环境保护期刊(英文)》 2020年第5期82-106,共25页
The study assessed the levels of some toxic metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) with their potential ecological and human health risks in water, African Catfish (Clarias gariepinus), Tilapia (Oreochromis spilur... The study assessed the levels of some toxic metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) with their potential ecological and human health risks in water, African Catfish (Clarias gariepinus), Tilapia (Oreochromis spilurus niger) and sediment samples from the Lower Usuma dam FCT, Nigeria during two major seasons in a year (rainy and dry seasons). Toxic metal concentrations were determined using Atomic Absorption spectrophotometry (Cd, Cr, Cu, Ni, Pb and Zn) and Atomic Emission Spectrophotometry (for As and Hg), and the results obtained were compared with national and international standards. The ecological and human health risk indices of the toxic metals present in the samples from the Dam were evaluated and interpreted. Tilapia from the dam posed the highest but medium ecological and human health risk due to Pb concentration of up to 7.11 mg/kg;ecological risk index of 35.55 and hazard quotient of 50.78. Overall ecological and human health risks were low due to the low concentrations of other toxic metals determined. As, Cd, Cr, Cu, Hg, Ni and Zn concentrations were all below WHO limits in the LUD water;Ni and Pb were above limits in the African Catfish and Tilapia samples. The data obtained were analyzed using one-way analysis of variance (ANOVA) and significant differences accepted at p ≤ 0.05. There was no statistical difference in the concentrations of toxic metals in water but there was significant difference between the concentrations of toxic metals in the fish and sediment samples. Correlation was found to exist between toxic metals in the water, fish and sediment analyzed from the dam. The ecological and human health risks of toxic metals in Lower Usuma dam require regular checks and monitoring hence, it was recommended by the researcher, that this and similar research work be carried out annually by NESREA and also, as research work by other students of Environmental and Analytical chemistry. 展开更多
关键词 Toxic Metals AAS AES Concentration ECOLOGICAL RISK Human Health RISK LOWER Usuma DAM Contamination Factor Water SEDIMENT FISH
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Surface Water Sediments Characterization Using Metallic Trace Elements (MTEs): Case of the Artisanal Gold Mining Sites of Kokumbo (Côte d’Ivoire) 认领
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作者 Kouassi Ernest Ahoussi Armand Patrick Yapo +1 位作者 Amani Michel Kouassi Yao Blaise Koffi 《环境保护(英文)》 2020年第9期649-663,共15页
The main purpose of this study is to characterize the surface sediments of the Kokumbo artisanal gold mining sites in Metallic trace Elements (MTEs). A total of 12 samples of surface water sediments were collected for... The main purpose of this study is to characterize the surface sediments of the Kokumbo artisanal gold mining sites in Metallic trace Elements (MTEs). A total of 12 samples of surface water sediments were collected for this study. The samples were analyzed using the Atomic Absorption Spectrophotometer (AAS). The mean concentrations of Mn (611.37 mg/kg) and Zn (955.86 mg/kg) in the sediments were very high compared to the standard in unpolluted sediments. The enrichment factor (EF) shows that there is an enrichment of Mn at some sites (EF (Mn) > 2). The presence of As, Mn, and Zn is also highlighted by the geo-accumulation index (I-geo) which shows slight pollution in Mn (0 < I-geo (Mn) < 1) on some sites. Moderate pollution for As (1 < I-geo (As) < 2) was determined at the treatment site and high pollution in Zn at some sites in the area (I-geo (Zn) > 3). This study shows that the presence of Zn in the sediments is linked to artisanal gold mining activities. Indeed, Zn is much used for gold recovery. The statistical analysis (PCA) shows, on the one hand, natural mineralization of the sediments and addition of metals linked to anthropic activities corresponding to the erosion of mining discharges. The surface sediments of the Kokumbo mining sites show pollution in As, Mn, and Zn. 展开更多
关键词 Artisanal Mining Enrichment Factor (EF) MTEs Pollution SEDIMENT
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大亚湾滨海湿地沉积物间隙水无机氮分布特征及其沉积物-水界面交换通量 认领
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作者 赵春宇 张凌 +3 位作者 江志坚 吴云超 柯志新 黄小平 《海洋环境科学》 CAS CSCD 北大核心 2020年第3期359-366,共8页
为探讨大亚湾滨海湿地沉积物间隙水中无机氮的时空分布规律及其环境效应,于2017年3月(枯水期)和8月(丰水期)分别采集了大亚湾湿地3个断面的沉积柱,测定了间隙水中无机氮含量并对其在沉积物-水界面交换进行了实验室培养实验。结果发现,... 为探讨大亚湾滨海湿地沉积物间隙水中无机氮的时空分布规律及其环境效应,于2017年3月(枯水期)和8月(丰水期)分别采集了大亚湾湿地3个断面的沉积柱,测定了间隙水中无机氮含量并对其在沉积物-水界面交换进行了实验室培养实验。结果发现,滨海湿地近岸上覆水中氮营养盐含量远高于大亚湾水体平均值,说明近岸人类活动对湿地生态系统中氮含量的影响较为严重,河流输送是其来源的主要途径。间隙水中NH4-N、NO3-N和NO2-N的平均含量分别为:770.60、7.63和7.39μmol/L,其中NH4-N是DIN的主要组分,约占DIN的85.82%~99.67%。室内培养实验发现,NH4-N、NO3-N和NO2-N的界面交换通量平均值分别为0.09、-0.18和0.36 mmol/(m^2·d),不同断面下DIN的交换速率存在明显差异。整体上,DIN的交换通量在枯水期约为0.41 mmol/(m^2·d),湿地沉积物表现为上覆水DIN的源;而丰水期沉积物则成为DIN的汇,其平均通量约为-0.23 mmol/(m^2·d)。对照实验结果表明,灭菌之后NH4-N、NO3-N和NO2-N的平均交换通量均有所降低,相比于原始组分别降低了76.5%、23.7%和50.3%,说明微生物在氮的转化中起到了非常重要的作用。 展开更多
关键词 沉积物 间隙水 无机氮营养盐 界面通量 滨海湿地
Strength May Lie in Numbers: Intertidal Foraminifera Non-Negligible Contribution to Surface Sediment Reworking 认领
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作者 Vincent M. P. Bouchet Laurent Seuront 《海洋科学期刊(英文)》 2020年第3期131-140,共10页
The contribution of benthic foraminifera to sediment bioturbation has widely been overlooked despite their huge abundance in intertidal soft sediments. In this preliminary study, we specifically chose to focus on two ... The contribution of benthic foraminifera to sediment bioturbation has widely been overlooked despite their huge abundance in intertidal soft sediments. In this preliminary study, we specifically chose to focus on two key species of benthic foraminifera in temperate intertidal mudflats, <i><span style="font-size:12px;font-family:Verdana;">Quinqueloculina seminula</span></i><span style="font-size:12px;font-family:Verdana;"> and </span><i><span style="font-size:12px;font-family:Verdana;">Ammonia</span></i> <i><span style="font-size:12px;font-family:Verdana;">tepida</span></i><span style="font-size:12px;font-family:Verdana;">, and first experimentally investigated their individual movements at the sediment surface. We subsequently derived from these observations the individual-level surface sediment reworking rates, and used the actual abundance of these species to extrapolate these rates at the population level. Individual surface sediment reworking rates </span><i><span style="font-size:12px;font-family:Verdana;">SSRR</span><sub><span style="font-size:12px;font-family:Verdana;">i</span></sub></i><span style="font-size:12px;font-family:Verdana;"> ranged between 0.13 and 0.32 cm<sup>2</sup><span style="white-space:nowrap;">·</span></span><span style="font-size:12px;"><sup><span style="font-family:Verdana;"></span></sup></span><span style="font-size:12px;font-family:Verdana;">ind</span><span style="font-family:Verdana;font-size:8.33333px;"><sup>-1</sup><span style="white-space:nowrap;">·</span></span><span style="font-size:12px;font-family:Verdana;">day<sup>-1</sup></span> <span style="font-size:12px;font-family:Verdana;">for</span><span style="font-size:10pt;font-family:;" "=""> <i><span style="font-size:12px;font-family:Verdana;">Q. seminula</span></i><span style="font-size:12px;font-family:Verdana;">, and between 0.12 and 0.28 cm<sup>2</sup><span style="white-space:nowrap;">·</span></span><span style="font-size:12px;font-family:Verdana;">ind<sup>-1</sup><span style="white-space:nowrap;">·</span></span><span st 展开更多
关键词 Benthic Foraminifera BIOTURBATION Surface Sediment Reworking Rate Intertidal Mudflats
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The controlling factors of high suspended sediment concentration in the intertidal flat off the Huanghe River Estuary 认领
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作者 Bowen Li Yonggang Jia +3 位作者 J.Paul Liu Jianfeng Su Xiaolei Liu Mingzheng Wen 《海洋学报:英文版》 SCIE CAS CSCD 2020年第10期96-106,共11页
The Huanghe River(Yellow River)is known by its high suspended sediment concentration(SSC)in its river mouth tidal flat.However,the factors controlling the high SSC over there are not well understood.Therefore,we condu... The Huanghe River(Yellow River)is known by its high suspended sediment concentration(SSC)in its river mouth tidal flat.However,the factors controlling the high SSC over there are not well understood.Therefore,we conducted 7-d hydrodynamic observations(water depth,wave height,and current velocity)and SSC measurements on the tidal flat off the Huanghe River Mouth.The data shows that in most of time,under the calm sea condition,the SSC ranges 0.1–3.5 g/L,and sediment discharge from the river is the main source.However,when hydrodynamics are enhanced in a tidal cycle and large-scale erosion occurs on the seafloor,resuspended sediment becomes the main source,and the SSC in the water column reaches 17.3 g/L.We find the suspended sediment flux is mainly controlled by the tidal current and Stokes drift,while the wave-induced shear stress could also affect the variation of suspended sediment flux.During the observation period,when sea under calm-rippled conditions,the current-induced resuspended sediment concentration(RSC)was greater than the wave-induced RSC.In contrast,in smooth-wavelet sea conditions,the wave-induced RSC was greater than the current-induced RSC,for instance,a single wave event was found to cause 11.8 cm seabed erosion within 6 h.This study reveals different controlling factors for the high SSC near a river-influenced tidal flat,and helps us get a better understanding of a delta's depositional and erosional mechanisms. 展开更多
关键词 Huanghe River(Yellow River) sediment re-suspension sediment transport WAVE CURRENT in-situ observation
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Increasing Conjugated Linoleic Acid Content in Milk and Cheese after Supplementing a Blend of Crude Soybean Oil Sediment Combined with Fish Oil to Grazing Dairy Cows 认领
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作者 Gerardo Antonio Gagliostro Liliana Elisabet Antonacci +5 位作者 Carolina Daiana Pérez Luciana Rossetti Martín Tassone Verónica Frossasco Favio Terreno Alvaro Ugartemendia 《动物科学期刊(英文)》 2020年第3期468-492,共25页
The aim of the work was to improve the healthy value of milk and cheese fatty acids (FA) by feeding a mix of crude soybean oil sediment (CSOS) combined with fish oil (FO) to grazing dairy cows. The CSOS is a by-produc... The aim of the work was to improve the healthy value of milk and cheese fatty acids (FA) by feeding a mix of crude soybean oil sediment (CSOS) combined with fish oil (FO) to grazing dairy cows. The CSOS is a by-product commonly discarded after oil extraction containing 3.3% moisture, 6% total ash and 70.7% oil, locally available, comparatively economic and easy to mix with other feed ingredients. The experiment lasted 55 days from September 30th to November 23th 2018 and was carried out at the dairy farm “Gacef” provider of milk to the dairy industrial plant “Capilla Del Se<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">&#241;</span>or” (CDS) located at the Villa María City, Córdoba Province, Argentine. A herd of 80 multiparous Holstein cows producing 24 kg<sup>-1</sup> milk·cow<sup>-1</sup>·day<sup>-1</sup> was used. The cows grazed an alfalfa and an oat pasture that represented about 47% of total dry matter (DM) intake supplemented at 8.5 kg DM·cow<sup>-1</sup>·day<sup>-1</sup> with a total mixed ration (TMR) composed (DM basis) by cracked corn grain (35.18%), whole plant corn silage (31.98%), pelletized soyben meal (17.99%), the CSOS supplement (13.85%) and FO (0.99%). The TMR was supplied by halves after each milking time in groupal feeders yielding 1.4 kg·cow<sup>-1</sup>·day<sup>-1</sup> of the CSOS and 0.1 kg·cow<sup>-1</sup>·day<sup>-1</sup> of FO. Before the start of lipid supplementation, milk samples (5) were obtained from the farm-tank representing the standar or reference milk (Ref-Milk). After 21 days of supplementary lipid supply, additional milk samples (5) were obtained representing the modified milk (Mod-Milk). Milk samples were analyzed for chemical composition and milk FA profile. At each time, sufficient quantities of both (Ref- and Mod-Milk) were collected for manufacturing six types of cheeses. The results were analyzed through the Student-T test for independent observations. Oil supplementation did not modify (P > 0.05) the 展开更多
关键词 Oil Supplementation Grazing Dairy Cow Milk Fatty Acids Conjugated Linoleic Acid CHEESE Fish Oil Crude Soybean Oil Sediment
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Influence of diversion angle on water and sediment flow into diversion channel 认领
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作者 Nashwan Kamalaldeen Alomari Badronnisa Yusuf +1 位作者 Thamer Ahmad Mohammad Abdul Halim Ghazali 《国际泥沙研究:英文版》 SCIE 2020年第6期600-608,共9页
Accumulation of the sediment in the stream of the diversion channels adversely affects its operational systems.Diversion channels are often constructed perpendicular to the main river.In this study,the water flow and ... Accumulation of the sediment in the stream of the diversion channels adversely affects its operational systems.Diversion channels are often constructed perpendicular to the main river.In this study,the water flow and sediment transport in the diversion channel with different angles were investigated in an attempt to maximize water discharge and minimize sediment discharge.A physical model with movable bed was used to simulate water and sediment flow with five diversion angles(θ)between(30°-90°).Moreover,three bed width ratios(Br)(the relation between diversion to main channel bed width)between 30%and 50%and five total discharges between(7.25 L/s to 12.25 L/s)were considered for each case of(θ).The results showed,up to 10%,increasing in proportion discharge ratios for 30 and 45 diversion angles compared with 90° diversion angle.The results also showed that the lowest diversion sediment concentration was provided by the(θ)of 30°.Across all scenarios,the average proportion concentration reduction was 64%,compared with 90diversion angle.Closer observation of the diversion system mechanism confirmed that decreased(θ)result in decreased sediment concentrations in the diversion channels.In conclusion,the diversion channel water and sediment discharge could be effectively managed by changing the(θ)to 30° or 45° instead of 90°. 展开更多
关键词 Diversion channel Diversion angle Lowest diversion sediment concentration Bed width ratio Sediment concentration
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Assessment of Runoff, Sediment Yields and Nutrient Loss Using the Swat Model in Upper Indus Basin of Pakistan 认领
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作者 Washakh Rana Muhammad Ali Ningsheng Chen +2 位作者 Waque Rana Muhammad Umar Almas Sundas Rahman Mahfuzur 《地球科学和环境保护期刊(英文)》 2020年第9期62-81,共20页
The main objective of this study is to understand the runoff, sediment yield and water quality of the Upper Indus River Basin of Pakistan. To achieve this goal, specific objectives have been met which include, setup o... The main objective of this study is to understand the runoff, sediment yield and water quality of the Upper Indus River Basin of Pakistan. To achieve this goal, specific objectives have been met which include, setup of a hydrological model using Soil and Water Assessment Tool (SWAT) then calibration and validation of the hydrological model using river discharges and in the end investigating the performance of the hydrological model by SWAT. This research will have great impacts on socio-economic conditions of Pakistan because study of upper Indus River basin is imperative to provide data needed for its management, and to warrant that it is sustainable to support the increasing population and conservational flows. A set of programmable mapping components MapWindow Geographic Information System (GIS) was used which is an open source GIS based mapping application. It is SWAT used spatially distributed information on elevation, land use, slope and soil. The program Sequential Uncertainty Fitting ver.2 (SUFI-2) in a combination of uncertainty analysis and calibration of outputs was used in SWAT-CUP. SWAT model used input data, which have climate information to obtain results. The observed climate data of temperature gauges and rain gauge were used as input in the SWAT model;the calibration results for three discharge stations were produced. The initial P-factor value was satisfactory but more iteration to attempt narrow uncertainty band with improving goal function, resulted in small percentage of observed data within uncertainty band. A warm up period of three years (1979-1982) was used for simulation of SWAT model. The model was calibrated for selected three catchments for the period 1982-2000 and validated for period 2001-2010. Results are quite comparable with the observed flows. 展开更多
关键词 Sediment Transport RUNOFF GIS SWAT Model Hydrological Modelling Nu-trient Loss
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Evaluation of Bottom Sediment Qualities in Ihetutu Minefield, Ishiagu, Nigeria 认领
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作者 R. Sha’Ato A. G. Benibo +1 位作者 A. U. Itodo R. A. Wuana 《地球科学和环境保护期刊(英文)》 2020年第4期125-142,共18页
Bottom sediment qualities in Ihetutu minefield were assessed to ascertain the impact of Pb-Zn mining activities on the sediments from streams, rivers and ponds in the area. Levels of Cu, Zn, Fe, Ni, Mn, Pb, Cd and Cr ... Bottom sediment qualities in Ihetutu minefield were assessed to ascertain the impact of Pb-Zn mining activities on the sediments from streams, rivers and ponds in the area. Levels of Cu, Zn, Fe, Ni, Mn, Pb, Cd and Cr and some physico-chemical parameters were measured in bottom sediments taken from four sampling stations (streams/mine pits) within Ihetutu minefield of Ishiagu which receives discharges from mining and human activities, and a control sampling station in Uturu (about 12 km away from study area). The study was conducted in four seasons (Rainy, Late Rainy, Dry, and Late Dry Seasons). Sample digestion was done with a temperature adjustable block digester. Heavy metal analysis was carried out with Flame atomic absorption spectrophotometer (FAAS) while other physico-chemical parameters were determined with standard field and laboratory procedures. Ranges of mean values of results obtained were;pH = 5.81 - 6.44, EC = 269.00 - 1545.00 μS/cm, Cl&#8722 = 43.30 - 112.33 mg/kg, alkalinity = 0.70 - 1.25 mg/kg, NO3-?= 5.90 - 7.90 mg/kg, TOC = 0.81 - 1.75 mg/kg, TOM = 1.40 - 3.02 mg/kg, Cu = 4.74 - 50.93 mg/kg, Zn = 26.78 - 57.07 mg/kg, Fe = 1066.19 - 1764.05 mg/kg, Mn = 36.66 - 42.96 mg/kg, Ni = 4.02 - 17.19 mg/kg, Pb = 38.01 - 162.23 mg/kg, Cd = 1.01 - 25.90 mg/kg, and Cr = 1.23 - 1.62 mg/kg. Assessment of heavy metals pollution, using pollution indices revealed that Contamination factor ranged from moderate to very high degree of contamination while Pollution load index also showed a deterioration of bottom sediment qualities. Geoaccummulation index indicated moderate to very high pollution, especially with Cu, Zn, Pb, and Cd in the mine pit, while Enrichment factor indicated high enrichments and inputs from anthropogenic sources especially, the Pb-Zn mining activities. Pollution of the area by heavy metals was in the order of Fe > Pb > Zn > Mn > Cu > Ni > Cd > Cr. Highest positive correlation (r = 0.992) was between Pb and Cu while the highest negative correlation (r = &#87220.789) was between Ni and Mn. Anal 展开更多
关键词 ANTHROPOGENIC ENRICHMENT Mining POLLUTION SEDIMENT
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Sediment dynamics and temporal variation of runoff in the Yom River,Thailand 认领
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作者 Matharit Namsai Butsawan Bidorn +2 位作者 Seree Chanyotha Ruetaitip Mama Nathamon Phanomphongphaisarn 《国际泥沙研究:英文版》 SCIE 2020年第4期365-376,共12页
The Yom River is one of the four major sediment sources to the Chao Phraya River in Thailand.Human activities and changes in climate over the past six decades may have affected the discharge and sediment load to some ... The Yom River is one of the four major sediment sources to the Chao Phraya River in Thailand.Human activities and changes in climate over the past six decades may have affected the discharge and sediment load to some extent.In the current study,the river discharge and sediment characteristics in the mainstream of the Yom River were investigated using the field observation data from 2011 to 2013 and the historical river flow and sediment data from 1954 to 2014 at six hydrological stations operated by the Royal Irrigation Department of Thailand(RID).The non-parametric Mann-Kendall test and double mass curve were used to analyze the sediment dynamics and temporal changes in the discharge of the Yom River.The results revealed that the sediment was mainly transported in suspension,and the bed-tosuspended sediment loads ratio varied between 0 and 0.05.The daily suspended sediment load(SSL)in the upper and middle basins had a strong correlation with the daily discharge and could be represented by power equations with coefficients of determination higher than 0.8.The daily suspended sediment load in the lower basin did not directly depend on the corresponding discharge because of the reduction in river slope and water diversion by irrigation projects.It also appeared that the river discharges and sediment loads were mainly influenced by climate variation(floods and droughts).Moreover,the average sediment transport of the upper,middle,and lower reaches were 0.57,0.71,and 0.35 million t/y,respectively.The sediment load in the lower basin decreased more than 50%as a result of changes in the river gradient(from mountainous to floodplain areas).The results from sediment analysis also indicated that the construction of the Mae Yom Barrage,the longest diversion dam in Thailand,and land-use changes did not significantly affect the sediment load along the Yom River. 展开更多
关键词 Suspended SEDIMENT load FLUVIAL SEDIMENT Chao Phraya RIVER basin DAM construction Climate change Human activities
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Grain-Size Distribution of Surface Sediments in the Bohai Sea and the Northern Yellow Sea: Sediment Supply and Hydrodynamics 认领
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作者 YUAN Ping WANG Houjie +1 位作者 WU Xiao BI Naishuang 《中国海洋大学学报:英文版》 SCIE CAS CSCD 2020年第3期589-600,共12页
The grain-size distribution of surface sediments in the Bohai Sea(BS) and the northern Yellow Sea(NYS), and its relationship with sediment supply and hydrodynamic environment were investigated based on grain-size comp... The grain-size distribution of surface sediments in the Bohai Sea(BS) and the northern Yellow Sea(NYS), and its relationship with sediment supply and hydrodynamic environment were investigated based on grain-size compositions of surface sediments and modern sedimentation rates. The results showed that the surface sediments in the BS and the NYS were primarily composed of silty sand and clayey silt with a dominant size of silt. In addition, the Yellow River delivered high amount of water and sediments to the BS, and they are dominated in surface sediments(mainly silt) in the Bohai Bay, the Yellow River mouth, the center of the BS, and the north coast of Shandong Peninsula. The coarse-grained sediments were mainly deposited at the river mouth due to the estuarine filtration and physical sorting. Meanwhile, there was a significant relationship among the modern sedimentation rate, the surface sediment grain size distribution and sediment transport pattern. The areas with coarser surface sediments generally corresponded low sedimentation rates because of strong erosion;whereas the sedimentation rate was relatively high at the place that the surface sediments were fine-grained. Furthermore, the grain-size trend analysis showed that the areas with fine-grained surface sediments such as the mud area in the central BS and the upper Liaodong Bay were the convergent centers of surface sediments, except for the Bohai Bay and the subaqueous Yellow River Delta where offshore sediment transport was evident. 展开更多
关键词 Bohai Sea and North Yellow Sea surface sediment grain size sedimentation rate sediment supply sedimentary dynamic environment
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Law of Distribution of Quantities of Shells on Togolese Littoral 认领
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作者 Kossi Bollanigni Amey 《土木工程期刊(英文)》 2020年第1期69-82,共14页
This study aims at analyzing the repartition of the quantities of shells of sand sediments of Togolese littoral, and at determining the law underlying their longitudinal and transversal distributions. Samples (210), c... This study aims at analyzing the repartition of the quantities of shells of sand sediments of Togolese littoral, and at determining the law underlying their longitudinal and transversal distributions. Samples (210), collected all along Togolese littoral starting from Togo-Ghana border up to Togo-Benin border, are subject to the test of sieving. Each refusal on sieve is tested against construction of shells by hydrochloric acid. The determination of the quantity of shells according to their size and to longitudinal and transversal distributions on the littoral is completed. As a conclusion, the quantity of shells in the sediments is getting lower and lower starting from the aerial mid-beach (14.2%) to the mid-foreshore (11.80%), and getting higher and higher from the mid-foreshore (11.80%) to the low-foreshore (13.32%). It is getting lower and lower according to the direction of sediments’ transportations. This quantity of shells is high (40.87%) in the fine-grained sands (&#216 &#216 > 2 mm) and low (>24.26%) in the average-grained sands (0.125 mm ≤ &#216 ≤ 2 mm). The average quantity of shells of 12.67% is lower than the recommended maximum quantity (30%) for the sands used for concrete. Thus, for the concrete works, the littoral sands might be seen as useful since they are granulating for concrete. 展开更多
关键词 SEDIMENT Togolese LITTORAL Quantity of SHELLS DISTRIBUTION
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近期长江源沱沱河输沙量随气候变化呈现阶梯上升 认领
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作者 张凡 史晓楠 +7 位作者 曾辰 王莉 肖雄 王冠星 陈瑶 张宏波 吕喜玺 Walter Immerzeel 《科学通报:英文版》 SCIE EI CSCD 2020年第5期410-418,共9页
河流输沙是流域水土流失和地表环境变化的重要表征.本研究分析了近年来沱沱河输沙量的变化及其主控因素.1986~2014年水文气象变量的序列显示,沱沱河气温、降水、地温、径流量、含沙量和输沙量均呈显著上升趋势,且主要归因于1997年前后... 河流输沙是流域水土流失和地表环境变化的重要表征.本研究分析了近年来沱沱河输沙量的变化及其主控因素.1986~2014年水文气象变量的序列显示,沱沱河气温、降水、地温、径流量、含沙量和输沙量均呈显著上升趋势,且主要归因于1997年前后的阶梯式增长,这可能是1997年的强厄尔尼诺事件影响的结果.双累积曲线和偏最小二乘结构方程模型分析显示,升温导致的融水增加辅以降水增加是径流量增加的主因,伴随水流侵蚀力和输沙能力的增强,径流量和含沙量增加共同促进了输沙量的增加.由于最大降水从六七月推迟至植被覆盖更好的七八月,植被保护一定程度上缓解了土壤侵蚀的加剧.此外,本研究进一步认识了青藏高原近期输沙量变化的控制过程,为区域水土保持管理提供了科学基础. 展开更多
关键词 ALPINE CATCHMENT Sediment flux CHANGING TREND Climate change
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