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Comparative Assessment of the Upstream and Downstream Water Qualities of River Tano in Ghana
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作者 Jackson Adiyiah Helena Aboagye-Larbi Mike Agbesi Acheampong 《Journal of Environmental Science and Engineering(A)》 2013年第5期283-292,共10页
River Tano, located in the Brong Ahafo region of Ghana, has a number of socio-ecological functions. Anthropogenic activities such as farming, washing, and discharge of industrial effluents into the river pose serious ... River Tano, located in the Brong Ahafo region of Ghana, has a number of socio-ecological functions. Anthropogenic activities such as farming, washing, and discharge of industrial effluents into the river pose serious threat to human health. In view of this, water quality campaign was carried out for a period of 12 months by taking samples from the source and the downstream end of the river and analysing for some physico-chemical parameters. The results showed that most of the physico-chemical parameters such as pH, fluoride, nitrite, manganese and temperature were not within the regulatory safe limit. Although the levels of total alkalinity, total iron, ammonia and phosphate kept fluctuating along the course of the river, the difference were not statistically significant apart from fluoride and phosphate which showed significant difference between the upstream and downstream levels. This may be attributed to anthropogenic activities such as farming and washing in the river which implies that human activities have impacted slightly on the water quality. It is recommended that the relevant stakeholders should come together to enforce the environmental laws regarding protection of water bodies and do continuous monitoring for early detection of any change in quality of the River Tano. 展开更多
关键词 PHYSICO-CHEMICAL water resources water quality River Tano upstream downstream.
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Upstream-Downstream Relationships in Terms of Annual Streamflow Discharges and Drought Events in Nebraska
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作者 Hong WU Leen Kiat SOH +3 位作者 Ashok SAMAL Tao HONG David MARX Xunhong CHEN 《Journal of Water Resource and Protection》 2009年第5期299-315,共17页
Upstream-downstream relationships of annual streamflow discharges and severity and frequency of stream-flow drought events are critical in understanding how streamflow droughts propagate over time and space. Such info... Upstream-downstream relationships of annual streamflow discharges and severity and frequency of stream-flow drought events are critical in understanding how streamflow droughts propagate over time and space. Such information can be used to resolve water disputes, trigger mitigation strategies, and understand how streamflow changes due to changes in the environment. During drought years, such information is even more critical as water resources are contested. The objective of this research is to study the upstream-downstream relationships of streamflow in Nebraska along four major river systems with diverse hydrologic characteris-tics and human activities: North Platte, Big Blue, Republican, and Niobrara. The relationships among the upstream and downstream stations along the four rivers are investigated by comparing several statistics de-rived from the annual flow discharge and on drought events. Trend analysis and coefficient of variation are applied to annual flow discharge values, and a host of drought-related parameters (e.g., annual maximum drought duration, annual accumulated drought duration, number of drought events) are also computed with respect to five different levels of streamflow drought events: water shortage, mild drought, moderate drought, significant drought, and extreme drought. The paired-t test and ANOVA with MIXED procedure are subse-quently applied to the statistics to observe whether there is a significant difference between upstream and downstream stations along a river. The analysis allows us to characterize the upstream-downstream relation-ships of the four river systems, laying the groundwork for further investigations to identify the reasons for some of the trends and observations. These findings will be essential in water resources management during or prior to hydrological droughts. 展开更多
关键词 Streamflow DROUGHT upstream-downstream Relationship Paired T-TEST Repeated Measures ANOVA with MIXED Procedure NEBRASKA
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Performance of the Wind Farm Parameterization Scheme Coupled with the Weather Research and Forecasting Model under Multiple Resolution Regimes for Simulating an Onshore Wind Farm 被引量:5
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作者 Rajabu J.MANGARA Zhenhai GUO Shuanglin LI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2019年第2期119-132,共14页
We use the Wind Farm Parameterization(WFP) scheme coupled with the Weather Research and Forecasting model under multiple resolution regimes to simulate turbulent wake dynamics generated by a real onshore wind farm and... We use the Wind Farm Parameterization(WFP) scheme coupled with the Weather Research and Forecasting model under multiple resolution regimes to simulate turbulent wake dynamics generated by a real onshore wind farm and their influence at the local meteorological scale. The model outputs are compared with earlier modeling and observation studies. It is found that higher vertical and horizontal resolutions have great impacts on the simulated wake flow dynamics. The corresponding wind speed deficit and turbulent kinetic energy results match well with previous studies. In addition, the effect of horizontal resolution on near-surface meteorology is significantly higher than that of vertical resolution. The wake flow field extends from the start of the wind farm to downstream within 10 km, where the wind speed deficit may exceed 4%. For a height of 150 m or at a distance of about 25 km downstream, the wind speed deficit is around 2%. This indicates that, at a distance of more than 25 km downstream, the impact of the wind turbines can be ignored. Analysis of near-surface meteorology indicates a night and early morning warming near the surface, and increase in near-surface water vapor mixing ratio with decreasing surface sensible and latent heat fluxes. During daytime, a slight cooling near the surface and decrease in the near-surface water vapor mixing ratio with increasing surface sensible and latent heat fluxes is noticed over the wind farm area. 展开更多
关键词 upstream downstream WIND FARM impact WIND FARM PARAMETERIZATION scheme WAKE flow dynamics
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Effects of Effluent from a Dumpsite on the Physicochemical Properties of River Achichum in Bamendakwe, Northwest Cameroon
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作者 Mofor Nelson Alakeh Keuwo Tiayong Francois +2 位作者 Nchofua Festus Biosengazeh Mikwa Cyprian Chunkang Njoyim Estella Buleng Tamungang 《Journal of Environmental Protection》 2024年第9期934-947,共14页
This study was aimed to assess the effects of effluent from a dumpsite on the physicochemical properties of river Achichum in Bamendakwe in the Bamenda I municipality, Northwest Region of Cameroon. The quality of wate... This study was aimed to assess the effects of effluent from a dumpsite on the physicochemical properties of river Achichum in Bamendakwe in the Bamenda I municipality, Northwest Region of Cameroon. The quality of water used for domestic purposes by the population of this area is mostly appreciated through its organoleptic assessment while no attention is paid to the physicochemical and microbiological properties. Samples (upstream, effluent, and downstream) were collected in the months of September 2022 and February 2023 and examined for organoleptic, physicochemical and bacteriological characteristics using standard methods. The river was contaminated to different extents by nitrates (28.56 - 149.91 mg/L), sulphates (246.89 - 725.42 mg/L) and heavy metals (0.01 - 0.04 mg/L for lead and 0.98 - 2.15 mg/L for aluminum). This contamination could be due to an inflow of the untreated effluent into the river. The river contained a high pollution level of lead and aluminum. Bacteriological investigations revealed that all the analyzed samples from the river contained indicators of faecal pollution such as Enterobacteria spp., E. coli, Streptococcus spp., Salmonella spp., Shigella spp., Staphylococcus spp. and Vibrio spp. Consequently, its utilization exposes consumers to health risks. Thus, water from the river should be treated prior to consumption. 展开更多
关键词 EFFLUENT upstream downstream Water Quality Faecal Contamination Bamendakwe
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The Comparison of Different Degree of Convexity and 3D Modeling of Involute Hyperbolic Arch Dam 被引量:3
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作者 DU Qi-lu DU Ting-na ZHAO Hai-feng 《Computer Aided Drafting,Design and Manufacturing》 2011年第2期7-12,共6页
Because of good quality of compressive resistance, the hyperbolic arch dam is being increasingly applied to engineering projects. In order to satisfy the needs of compressive resistance under the conditions of high wa... Because of good quality of compressive resistance, the hyperbolic arch dam is being increasingly applied to engineering projects. In order to satisfy the needs of compressive resistance under the conditions of high water pressure, a stress analysis is required for the dam. During the stress analysis process however, due to the complexity of the three-dimensional modeling, it is very hard to form a model. Therefore, the stress analysis process is a barrier for the arch dam. In this article, based on the research of the new line-type arch dam, a mathematical model in different degree of convexity conditions of the dam is established; using the C + + language program, a computer three-dimensional model simulation is realized on AutoCAD. The accurate three-dimensional model is providing a finite element optimization design of the involute hyperbolic arch dam for the next step. 展开更多
关键词 the involute hyperbolic arch dam arch axis upstream arch arc downstream arch arc 3D modelling C program design
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Relationship between Concentration and Location of theHerbal Industry
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作者 Rohana Abd Rahman Ariff Fahmi Abu Bakar 《Journal of Environmental Science and Engineering(B)》 2019年第5期186-189,共4页
Malaysia aspires to become developed and high income nation by year 2020. Under the Tenth Malaysia Plan, herbal industry was the first Entry Point Project for Agricultural National Key Economic Area in Economic Transf... Malaysia aspires to become developed and high income nation by year 2020. Under the Tenth Malaysia Plan, herbal industry was the first Entry Point Project for Agricultural National Key Economic Area in Economic Transformation Programme. To understand the current status of the herbal industry, FRIM (Forest Research Institute Malaysia) conducted the survey on 6,923 herbal chain players, consisted from upstream to downstream activities. A face-to-face interview was conducted using a structured questionnaire to gather the information. This paper highlighted the relationship between concentration of the herbal industry and urbanization’s status of the areas. The finding shows that a statistically significant difference exists between category of herbal activities and status of the areas. The upstream activities are more concentrated in rural areas, while most of downstream activities in urban areas. It is in line with central place of theory on how settlements and places are located in relation to one another and their functions. Therefore, to further develop the herbal industry, the government should consider strategic location by category of industrial activities in policies planning, programmes implementation and providing infrastructural support needed by the industry. 展开更多
关键词 upstream downstream HERBAL INDUSTRY industrial LOCATION central place theory
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THE IMPACTS OF INTERACTION OF A TYPHOON WITH THE MIDLATITUDE TROUGH ON ITS TRACK AFTER THE RECURVATURE 被引量:1
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作者 王凯 陈华 王金梅 《Journal of Tropical Meteorology》 SCIE 2017年第2期202-209,共8页
Three typhoon cases are selected to conduct a series of simulations that are initialized from sequential analyses. The results show that the forecast error in crucial area where a tropical cyclone(TC) interactes with ... Three typhoon cases are selected to conduct a series of simulations that are initialized from sequential analyses. The results show that the forecast error in crucial area where a tropical cyclone(TC) interactes with the upstream trough is highly correlated to the track forecast error after the TC recurvature. Furthermore, sensitivity experiments confirm that the developments of the midlatitude downstream circulations and then the TC track after its recurvature are highly sensitive to the TC intensity and its location relative to the upstream trough, which can give an example or one way of sensitivity of the TC track to the TC-trough interaction. If the TC interacts with the upstream trough more strongly(e.g., the TC being intensified or getting closer to the upstream trough), the downstream circulations will be more meridional, thus the TC track will be more northerly and westerly; otherwise, the downstream circulations will be more zonal, and the TC track will be more southerly and easterly. 展开更多
关键词 tropical cyclone typhoon track typhoon recurvature midlatitude downstream circulations upstream trough PV gradient
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Phenomenon of the sediment deposition in a hydraulic jump region of open channels
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作者 XU Wei-lin WANG Guo-guang +1 位作者 FU Shi-hao WEI Wang-ru 《Journal of Mountain Science》 SCIE CSCD 2022年第7期1874-1885,共12页
The hydraulic jump is a typical sudden change for mountain river areas.The effects of local hydraulic jumps on the particle transport capacity decrease and local flow resistance increase cannot be ignored as the sedim... The hydraulic jump is a typical sudden change for mountain river areas.The effects of local hydraulic jumps on the particle transport capacity decrease and local flow resistance increase cannot be ignored as the sediment deposition disaster can amplify the flash flood disaster.The present research investigates the influences of a hydraulic jump on the individual particle movement and sediment deposition in a laboratory flume.The overall processes of a single particle movement are captured by a high-speed camera.The distribution of sediment deposition along the hydraulic jump is obtained statistically.The results show that both the particle size and the ratio of the upstream and downstream Froude numbers affect the particle motion process.A single particle coming from upstream gradually decelerates and finally stops at the hydraulic jump section because of hydraulic jump resistance.The particle acceleration first increases and then decreases during the time-domain process,and the attenuation trends are fast with the increase of ratio of upstream and downstream of Froude numbers.The increase of the maximum acceleration with sediment flows follows a linear trend approximately,which indicates that the kinetic features of the single sand particle are determined by the coupling effects of the hydraulic jump resistance and the sand dynamic properties.With the increase of sediment rate and sand particle size,the resistance effect of hydraulic jump on sediment deposition rate along the flow direction gets strong and the sediment deposition area is mainly located upstream of the hydraulic jump region.The present study shows that the possible sediment supply upstream must be obtained for identifying the disaster risk combined with the local hydraulic jump conditions.Further researches about the detailed critical condition deduced from the relationship between the water flow and sediment deposition are required to confirm and extrapolate present results to other applications. 展开更多
关键词 RATIO of upstream and downstream Froude
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DISTRIBUTION AND CHARACTERIZATION OF NON-VOLATILE CHEMICAL MUTAGENS IN SEDIMRNTS OF AN INDUSTRIALLY IMPACTED RIVER
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作者 M.Wilson Tabor Marcus C.Waldron Alan R.White 《癌变.畸变.突变》 CAS CSCD 1991年第S1期177-177,共1页
A coupled bioassay/analytical fractionation approachwas used to isolate genotoxic contaminants from riversediments collected at points upstream,adjacent to,and downstream from centers of major industrial andmunicipal ... A coupled bioassay/analytical fractionation approachwas used to isolate genotoxic contaminants from riversediments collected at points upstream,adjacent to,and downstream from centers of major industrial andmunicipal activities.Sediments were milled withsodium sulfate and sequentially extracted with anonpolar to polar solvent series;extracts 展开更多
关键词 downstream sequentially upstream FRACTIONATION extracts centers polar ISOLATE EXCHANGES SALMONELLA
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Upstream-downstream cooperation approach in Guanting Reservoir watershed
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作者 YANGZhi-feng ZHANGWen-guo 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2005年第4期676-680,共5页
A case study is introduced and discussed concerning water dispute of misuse and pollution between up\| and down\|stream parts. The relations between water usage and local industrial structures are analyzed. Results sh... A case study is introduced and discussed concerning water dispute of misuse and pollution between up\| and down\|stream parts. The relations between water usage and local industrial structures are analyzed. Results show it is important to change industrial structures of the target region along with controlling water pollution by technical and engineering methods. Three manners of upstream-downstream cooperation are presented and discussed based on the actual conditions of Guangting Reservoir watershed. Two typical scenarios are supposed and studied along with the local plan on water resources development. The best solution for this cooperation presents a good way to help the upstream developing in a new pattern of eco-economy. 展开更多
关键词 WATERSHED COOPERATION upstream-downstream industrial structures Guanting Reservoir
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Mapping the Supply Chain Issues SMEs and Impact for Quality Products
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作者 Ayi Tejaningrum Anton Mulyono Azis Maya Irjayanti 《Management Studies》 2016年第1期9-15,共7页
Until now, the issue of quality of the products of SMEs (small and medium enterprises) remains the main issues as the cause of low ability to compete. This study focused into the issue of what happened with regard t... Until now, the issue of quality of the products of SMEs (small and medium enterprises) remains the main issues as the cause of low ability to compete. This study focused into the issue of what happened with regard to the quality of products in the supply chain SME products. This study aims to describe how the culture of quality in the supply chain of SMEs and their role in contributing to the lack of SME products. The study involved 128 SMEs in the food processing industry cluster and garment industry. The research uses qualitative method with case study approach. The results showed an average internal quality culture reached 3.62661 supply included in the category enough. Of the five industry cluster, a culture of quality in the internal supply chain is the best T-shirt industry (4.3385) in both categories, while other four clusters exist in enough categories, with grades: hoods (3.661), soy crisps (3.6635), cassava chips (3.64), and the last chips fish balls (2.829). The low average internal quality culture supply mainly is in industrial processing of cassava chips and chips fish balls. One reason is the low awareness of quality. There is no technology and equipment adequate to safeguard the stability of quality. The upper most excellent quality culture occurred in the supply chain, where the product is controlled by big industry, is the industry shirts (4.018), soy crisps (3.613), and hoods (3.473), while when in the upstream industry controlled by small or SMEs, there is deterioration in the cultural values of quality: cassava chips (2.917) and chips fish balls (2.781). For downstream, 100% controlled by SMEs, there is an average value of quality culture 3.5662. 展开更多
关键词 supply chain upstream downstream a culture of quality small and medium enterprises (SMEs)
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Downstream Competition and Upstream Innovation:Theory and Evidence from China
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作者 Jing Dai Guanchun Liu +2 位作者 Ziqi Ye Haiou Mao Yongwei Ye 《China Finance and Economic Review》 2024年第1期67-87,共21页
Competition is the catalyst of corporate innovation,which is the foundation of a country's core competitiveness.From the view of vertical industrial chain,this paper examines how downstream competition affects ups... Competition is the catalyst of corporate innovation,which is the foundation of a country's core competitiveness.From the view of vertical industrial chain,this paper examines how downstream competition affects upstream firms'innovation output.Given innovation helps reduce the production cost of each product,increasing demand of intermediate products caused by downstream competition enhances the marginal revenue of upstream firms'innovation,thus leading to an innovation incentive effect.To identify causality,we utilize China's WTO accession,a quasinatural experiment,to calculate downstream competition combined with import tariff reduction and input-output table,and then run a difference-in-difference regression.Using the data of Annual Survey of Industrial Firms and State Intellectual Property Office,our results find that downstream competition has a significantly positive impact on upstream firms'innovation,and this effect is more pronounced in firms with less industry competition,greater initial innovation capacity and weaker financial constraints.Moreover,the number of firms,the degree of industry competition and the scale of intermediate products in the downstream sector increase,confirming the market size channel.In sum,our findings document that downstream competition can motivate upstream firms to innovate through vertical industrial chain,providing some useful insights for China to build a fair market competition environment and promote innovation-driven growth regime. 展开更多
关键词 downstream competition upstream firms'innovation vertical industrial chain market size effect
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Dissolved Organic Matter Features of Three Adjacent Eastern Mediterranean Urbanized Watersheds
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作者 Nour Abboud Elias Michel Maatouk +1 位作者 Zeinab Matar Veronique Kazpard 《Open Journal of Modern Hydrology》 CAS 2024年第3期153-173,共21页
Landscape urbanization broadly affects ecosystems in coastal watersheds, but, until now, the influence of nonpoint source urban inputs on dissolved organic matter (DOM) amount, composition, and source is poorly unders... Landscape urbanization broadly affects ecosystems in coastal watersheds, but, until now, the influence of nonpoint source urban inputs on dissolved organic matter (DOM) amount, composition, and source is poorly understood. To understand how DOM composition varied with urbanization, fluorescence excitation-emission matrices (EEMs) were determined for urban and non-urban waters from upstream to downstream sites along three adjacent coastal watersheds that flow into the Mediterranean Sea. Two humic DOM fluorescent components (humic-like and fulvic-like peaks) and two proteinic components (tyrosine-like and tryptophane-like peaks) were identified by EEM fluorescence. The results indicated that urbanization had an important influence on DOM concentration and composition, with urban waters having a high degree of DOM variation due to different land uses surrounding each body of water. Urban waters show a higher DOM fluorescence index (FI), the highest fluorescence intensity of protein-like manifested also by BIX values, and a lower value of the humification index (HIX) than non-urban waters which were dominated by allochthonous inputs. In addition, the EEM was compared in dry and wet season where higher DOM amounts and FI appeared in summer due to autochthonous production coming from algae growth compared to allochthonous input from rainfall dominated in wet season. The concentration of DOC increased from upstream to downstream for the three rivers, especially Beirut River. The increase in DOC values was observed in both dry and wet seasons by 39 and 19 times respectively compared to upstream (0.93 - 0.91 mgC/L). 展开更多
关键词 Dissolved Organic Matter DOM EEM Fluorescence Spectroscopy Autochthonous/Allochthonous DOM Urbanization upstream/downstream Wet/Dry Season
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陆相层序地层构型与沉积模拟研究现状及进展
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作者 邵龙义 王浪浪 +2 位作者 连豪杰 朱红涛 朱筱敏 《古地理学报》 北大核心 2025年第1期1-15,共15页
层序地层学作为一种新的盆地分析方法,受到广大地质学家的重视,尤其是陆相层序构型与数值模拟研究已成为一个国际性热门方向。文中总结了陆相层序构型在国内外的研究进展,介绍了国外近年来的“下游控制区”和“上游控制区”概念以及层... 层序地层学作为一种新的盆地分析方法,受到广大地质学家的重视,尤其是陆相层序构型与数值模拟研究已成为一个国际性热门方向。文中总结了陆相层序构型在国内外的研究进展,介绍了国外近年来的“下游控制区”和“上游控制区”概念以及层序构型特征,“下游控制区”发育依赖于相对海(湖)平面变化的“低位正常海(湖)退”、“海(湖)侵”、“高位正常海(湖)退”和“下降阶段”体系域,“上游控制区”发育不依赖相对海(湖)平面变化的高河道合并体系域和低河道合并体系域。国内层序构型研究也有多种观点,最有代表性的应该是“L型、T型、TH型、H型(E-H型和L-H型)”层序构型的划分。陆相层序模拟已经从水槽物理实验为主发展到当今以数值模拟及水槽实验并举的时代。在介绍层序数值模拟发展史、国内外研究现状的基础上,重点介绍了SEDPAK正演化模拟、SEDSIM正演数值模拟、基于Delft3D模型的三维正演模拟、DIONISOS的三维正演模拟及基于N-S方程的层序数值模拟等5种数值模拟方法,总结了陆相湖盆层序构型及数值模拟在油气勘探开发领域的应用情况,分析了目前存在的理论问题、数值模拟技术难点及数值模拟未来的发展方向。 展开更多
关键词 陆相层序地层 下游控制区 上游控制区 层序构型 数值模拟
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带式输送机顺煤流启动速度的节能控制研究
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作者 刘海锋 任进博 周鑫 《自动化仪表》 2025年第1期63-67,共5页
为保证带式输送机的稳定运行,提出基于顺煤流启动的带式输送机变频调速节能控制优化方法。利用积分原理分析带式输送机皮带煤量检测装置结构,明确不同传感器的安装位置。使用超声波传感器、速度传感器分别采集带式输送机皮带煤流量、各... 为保证带式输送机的稳定运行,提出基于顺煤流启动的带式输送机变频调速节能控制优化方法。利用积分原理分析带式输送机皮带煤量检测装置结构,明确不同传感器的安装位置。使用超声波传感器、速度传感器分别采集带式输送机皮带煤流量、各点带速数据。结合目前煤流量、带速状态,设计基于模糊可编程逻辑控制器(PLC)的输送机变频调速节能优化方法。通过变频电动机调节带式输送机以自动化调节带速,完成带式输送机变频调速节能控制优化。试验结果表明:所提方法在执行带式输送机变频调速节能控制优化操作时,未出现电能浪费和皮带磨损问题。该方法可使带式输送机的启动带速、张力波动幅度明显变小,并使运行稳定性变高。该方法有效解决了电能浪费和皮带磨损等问题,保证了带式输送机顺煤流的稳定运行。 展开更多
关键词 顺煤流 调速节能 煤流量检测 可编程逻辑控制器 变频电动机 积分原理 带速波动 张力波动
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Experimental investigation on the wake interference among wind turbines sited in atmospheric boundary layer winds 被引量:6
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作者 W.Tian A.Ozbay +1 位作者 X.D.Wang H.Hu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2017年第4期742-753,共12页
We examined experimentally the effects of incoming surface wind on the turbine wake and the wake interference among upstream and downstream wind turbines sited in atmospheric boundary layer(ABL) winds. The experimen... We examined experimentally the effects of incoming surface wind on the turbine wake and the wake interference among upstream and downstream wind turbines sited in atmospheric boundary layer(ABL) winds. The experiment was conducted in a large-scale ABL wind tunnel with scaled wind turbine models mounted in different incoming surface winds simulating the ABL winds over typical offshore/onshore wind farms. Power outputs and dynamic loadings acting on the turbine models and the wake flow characteristics behind the turbine models were quantified. The results revealed that the incoming surface winds significantly affect the turbine wake characteristics and wake interference between the upstream and downstream turbines. The velocity deficits in the turbine wakes recover faster in the incoming surface winds with relatively high turbulence levels. Variations of the power outputs and dynamic wind loadings acting on the downstream turbines sited in the wakes of upstream turbines are correlated well with the turbine wakes characteristics. At the same downstream locations, the downstream turbines have higher power outputs and experience greater static and fatigue loadings in the inflow with relatively high turbulence level, suggesting a smaller effect of wake interference for the turbines sited in onshore wind farms. 展开更多
关键词 turbulence winds upstream downstream turbine simulating turbulent averaged faster fatigue
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Experimental Study of Oil Pipeline Leak Processes 被引量:3
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作者 Agbakwuru Ahamefula Jasper Gudmestad Tobias Ove Bilstad Torleiv 《Journal of Environmental Protection》 2012年第7期597-604,共8页
This work provides a description of oil leak/spill processes from containment such as pipeline. Understanding of such processes is important in order to adequately estimate oil spills and to justify an appropriate eme... This work provides a description of oil leak/spill processes from containment such as pipeline. Understanding of such processes is important in order to adequately estimate oil spills and to justify an appropriate emergency action for minimizing spills. Internal diameters of pipes used in the study are within 4 inches. Leaks are simulated from plastic pipeline oil containment fitted with valves. The leak response with time when upstream and downstream valves are operated is studied. Within the internal diameters of pipelines considered in the tests, two ranges of leak characteristics are evident;the “holding range” and the “flowing range” characteristics. The consequences of these characteristics in the oil industry operations have been discussed. The work suggests a spill estimation method based on this knowledge. Furthermore, in order to minimise spill in event of pipeline failure, it is observed that the optimum action on pipeline operational valves, is the immediate closure of upstream valve, followed by the downstream valve, nearly simultaneously. Future work will extend the test to larger diameter pipelines to attempt developing a mathematical approach for estimating limits of the “holding range” characteristics of pipelines given appropriate parameters and in-field test. 展开更多
关键词 OIL SPILL OIL LEAK Pipeline downstream VALVE upstream VALVE Early LEAK Event
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Three Gorges Project——key to harness and develop Yangtze River
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作者 Chen Jisheng Yangtze River Scientific Research Institute 《Electricity》 1992年第3期11-17,共7页
The upper Yangtze upstream ofYichang with a drainage area of1,000,000 km^2 brings an average annualrunoff to Yichang by 450 km^3 of river water,the drastic variation and uneven distributionof which often causes severe... The upper Yangtze upstream ofYichang with a drainage area of1,000,000 km^2 brings an average annualrunoff to Yichang by 450 km^3 of river water,the drastic variation and uneven distributionof which often causes severe floods for fer-tile alluvial plains of middle and lower Yang- 展开更多
关键词 YANGTZE floods reservoir upstream DRASTIC river season drainage uneven downstream
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高梯度磁选中非磁性颗粒的机械夹杂行为 被引量:1
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作者 张波 杜力 +2 位作者 李双佳 王一凡 郑霞裕 《有色金属工程》 CAS 北大核心 2024年第1期74-82,共9页
非磁性矿物颗粒的机械夹杂是影响高梯度磁选选择性的重要因素。基于自主设计的高梯度磁选试验装置,对磁介质上、下游累积物进行冷冻、剥离和独立分析,系统研究了各种关键参数对非磁性颗粒机械夹杂行为的影响。结果表明,磁介质下游捕集... 非磁性矿物颗粒的机械夹杂是影响高梯度磁选选择性的重要因素。基于自主设计的高梯度磁选试验装置,对磁介质上、下游累积物进行冷冻、剥离和独立分析,系统研究了各种关键参数对非磁性颗粒机械夹杂行为的影响。结果表明,磁介质下游捕集的选择性都优于上游。非磁性矿物的机械夹杂主要发生在介质上游,增加给矿流速和减小非磁性颗粒的粒度可以提高高梯度磁选的选择性,磁场强度对介质上下游机械夹杂的影响较小。在较低流速条件下,弱化上游捕集和强化下游捕集具有重要意义,并提出了提高选择性的两种潜在技术方案。 展开更多
关键词 高梯度磁选 机械夹杂 上下游累积 选择性
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MIIT Convened Work Meeting for Upstream and Downstream Cooperation Mechanism of Aluminum Material For Civilian Aircraft
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《China Nonferrous Metals Monthly》 2015年第10期9-10,共2页
On September 15,2015,the Department of Raw Material Industry and the Department of Equipment Industry of the Ministry of Industry and Information Technology(MIIT)jointly organized and convened the first work meeting f... On September 15,2015,the Department of Raw Material Industry and the Department of Equipment Industry of the Ministry of Industry and Information Technology(MIIT)jointly organized and convened the first work meeting for upstream and downstream cooperation mechanism of aluminum material for civilian aircraft in Shanghai.Entrusted by 展开更多
关键词 cooperation downstream AIRCRAFT upstream jointly o
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