Determining and comparing the levels of heavy metal concentrations in two selected urban river water

This paper discussed the heavy metal pollution levels and the clean-up activities to improve the Gombak and Penchala River water quality in Kuala Lumpur. The Gombak River is a tributary of the Klang River passing through Kuala Lumpur. The Penchala River passes through the city of Petaling Jaya. Metal concentration levels as reported by the Department of Environment of Malaysia were used to assess the state of metal contamination of the rivers. The effectiveness of government efforts through engineering and river works and public awareness campaigns to strive for a healthier Gombak River and Penchala River was observed over a period from 1997 to 2009. Results showed that the concentrations of metals in the Gombak River were generally slightly better than those of the Penchala River. The Penchala River showed a better rate of quality improvement than the Gombak River but the absolute concentration values were generally higher.     

Corrosion of Mild Steel by Urban River Water

The corrosion processes of mild steel immersed in river water were investigated. The reaction of the Bahlui River on common steel used in domestic and industrial installations was studied. The corrosion of mild steel is an extensive topic approached in different media, yet little information about river water as a corrosive has been reported. The experimental determinations were performed for short term immersion of four alloys in the laboratory. By using Tafel extrapolation and electrochemical impedance spectroscopy, the corrosion of the alloys was investigated. Scanning electron microscopy coupled with energy dispersive X-ray analysis and Fourier-transform infrared spectroscopy were employed to characterize the morphology of corrosion products and identify their phases. The corrosive activity of river water leads to the formation of inner compact and outer porous layers. The differences between corrosion products formed in the presence of underground and surface waters are described.     

工业纯镁的往复挤压工艺及晶粒细化效果

在150,175,200,225,250℃对工业纯镁进行不同道次的往复挤压,用光学显微镜研究了挤压温度和挤压道次对晶粒细化效果的影响。结果表明:150℃是工业纯镁能够进行往复挤压的最低温度;随着挤压温度的升高,工业纯镁的塑性提高,挤压应力下降,但晶粒细化效果有所下降;随着挤压道次增加,晶粒进一步细化;最佳挤压温度为200℃,最佳挤压道次为4次。     

Application of large scale PIV in river surface turbulence measurements and water depth estimation

Large-Scale Particle Image Velocimetry (LSPIV) has emerged as a reliable technology to measure river surface flow velocity distribution and can be applied to estimate river discharge. Fewer studies have explored the capability of surface turbulence measurements using LSPIV. In this paper, LSPIV is applied to evaluate statistics of surface turbulence of a natural river. Turbulence measurements including velocity fluctuation, velocity spectra and the dissipation rate of turbulent kinetic energy (TKE) are validated by comparing with those measured by an Acoustic Doppler Velocimeter (ADV). Traditionally, estimation of stream discharge through LSPIV needs a secondary measurement to determine river bathymetry and water depth. A new method is presented here to demonstrate that for a fully developed and channel-controlled flow, the cross section geometry can be estimated from the combined measurements of surface mean velocity and the dissipation rate, following the Manning-Strickler formula. Therefore, river discharge can be estimated with LSPIV along with a calibrated Manning's roughness, without additional bathymetry survey. The proposed new method is applied to measure discharge in Milwaukee River (Milwaukee, Wisconsin, U.S.A.), which agreed well with data obtained from a nearby streamgage station.     

基于物联网的分布式水文动态监测及预警系统

为了实现对河流水文信息的自动化集中监测,采用物流网技术设计了分布式水文动态监测及预警系统,该系统主要由多个水文监测节点、OneNET云平台和监测中心组成。水文监测节点采用控制器STM32F103ZET6和各类水文传感器设计而成,并通过带有MQTT协议的DTU模块将采集到的水文数据实时发送到OneNET云平台。云平台接收来自不同节点的数据,然后按照预定的模式进行存储,同时生产报表供水利工作人员分析使用。水文监测中心通过调用API函数获取云平台的数据,当水文数值超过预警阈值时,会自动向报警系统发出信号,并提醒工作人员和群众采取措施或者紧急撤离,避免人员和财产损失。通过对北汝河紫罗山水文站的流量进行测试结果表明:设计的系统工作稳定、采集数据准确,成功获取了2020全年的河水流量数据,为研究该流域的水文变化情况提供了强有力的数据支持。     

黑河干流出山口水资源演变与中下游生态环境保护

经过对黑河干流出山口流域近45年的降水、径流等水文要素及演变趋势分析,得出以下结论:水资源演变趋势总体上具有跌宕上升的不显著的增加趋势,降水增加趋势大于径流增加的趋势,同时随着全球气温变暖,黑河出山口天然来水保持相对稳定并略有增加的趋势.针对黑河中下游地区社会、经济持续发展对水资源的需求与生态环境脆弱的现状,提出了生态环境保护的建议.     

A study of tribology of Travan heads in linear tape recording

Tape cycling experiments were performed with a Travan™ linear tape system using metal particle (MP) media. The effects of various environmental conditions, particularly water content, on the tribology of the head/tape interface were studied. Auger electron spectroscopy (AES) and atomic force microscopy (AFM) were used to characterise the chemical and physical surface changes that occurred at the head surfaces. Transfer of material from the media to the head was observed at each condition. X-ray photoelectron spectroscopy (XPS) was used to identify the chemical changes that occurred at the media surface. This showed that in all areas of the tape, the amount of detected iron had increased, while the nitrogen (binder indicator) signal had decreased. Significant differences in elemental concentrations were also detected between areas directly in contact with the cartridge drive belt compared to those not in contact. Pole tip recession (PTR) was around 50–65 nm after 5000 passes, but increased at the higher water contents. AES results showed that stain is a function of water content, not relative humidity. It was noted that a larger ceramic grain size seemed to increase PTR.     

机淤固堤技术在堤河治理试点工程中的应用

由于黄河洪水、泥沙的长期作用,使黄河下游形成了堤河,对黄河大堤造成严重威胁,给防洪带来被动.2002年-2003年经黄委会批准,德州黄河河务局招标对德州境内的水坡滩区堤河进行了治理.德州黄河建业工程有限责任公司中标,利用机淤固堤技术组织淤填施工.工程完成后,堤根淤填高程与附近滩面高程基本一致,消除了汛期可能堤河造成顺堤行洪的威胁,堤河治理试点工程取得了成功.     

工业衡器产品的无线通信

工业无线通信是革命性技术,近年来发展迅猛,工业衡器厂商应尽快推出无线化的产品,满足用户的需求。本文首先介绍了三个工业无线通信标准：WirelessHART、ISA100.11a和WIA-PA,然后简述了工业无线通信系统架构,最后详细介绍了工业衡器产品无线化的三个途径：自行开发全套无线产品,通过通用接口与无线模块集成,产品集成。     

2019年工业车辆行业市场简要分析

2019年,对于中国工业车辆行业来说属于复杂的一年,行业不仅要应对前几年高速发展后需要调整的压力,还要面对中美贸易摩擦、环保要求提高等因素的影响,一年来,在全行业企业共同努力下,总销售量保持了平稳略有增长的局面,全年机动工业车辆销售量突破60万台,国内市场取得了5.88%的增长,达到45.6万台;出口出现近年来少有的负增长,下跌8.45%,跌幅相比上半年有所缩小;全行业总销售量为608341台,相比2018年全年的597152台,增长了1.87%。     

汾河污染总量控制中水域容许纳污量计算模型的选用

讨论汾河污染总量控制中，如何根据汾河水文特性和污染物特征，选用适当的水质模型，确定水域容许纳污量。     

河流健康与水安全思考

河流健康不是严格意义上的科学概念而是一种河流管理的评估工具。人类在开发利用流域水资源的过程中，由于保护不够或滥加利用，一些河流发生污染、断流现象，影响了河流的自然和社会功能，失去了河流的自身价值，危及河流的健康生命。维系河流的健康生命和水安全密切相关。河流污染是我国河流健康的最大威胁，治污是我国现阶段河流生态环境建设的首要任务，同时在水电工程建设中应强化对生态环境的监管。     

基于多个隧道掘进机工程数据回归分析的滚刀磨损评价方法

为了评价不同隧道工程围岩对隧道掘进机(TBM)滚刀磨损的影响,解决滚刀磨耗难以准确预测的问题,基于北疆供水二期、吉林引松供水、陕西引汉济渭、大瑞铁路高黎贡山、深圳地铁10号线等多个隧道(洞)工程TMB滚刀磨损数据,选取岩石单轴抗压强度、岩石等效石英含量、岩石磨蚀性指标、岩体完整性指标、滚刀破岩体积磨损速率等参数进行数据回归分析。结果表明：岩石磨蚀性指标与单轴抗压强度和等效石英含量的乘积成对数函数关系,滚刀破岩体积磨损速率与岩体完整性系数和岩石磨蚀性指标的乘积成指数函数关系,滚刀刀圈寿命与岩体完整性系数和岩石磨蚀性指标的乘积成负指数函数关系。并并在此基础上,建立了岩石磨蚀性和滚刀磨损性的分级评价准则。     

黄河下游放淤固堤技术发展综述

黄河下游放淤固堤是提高工程抗洪强度的重要措施之一.历经自流放淤、提水淤背和机淤固堤三个阶段,从初期试验、推广到大规模应用历时已50余年,施工技术逐步成熟,施工设备因地制宜,效率随之提高,不同时期的不同技术,为后来的技术发展奠定了基础.     

Investigation of the effect of roll forming pass design on main redundant deformations on profiles from AHSS

The tooling design in the roll forming process plays a major role in the quality and successful mass production of a variety of complex profiled products, in many industrial sectors. The roll forming line is comprised of consecutive forming passes. Each roll forming pass consists of a set of rotating rollers able to bend the material as it passes through them. The roll forming pass design plays a major role in the production of profiles. The introduction of advanced high strength steels (AHSS), such as the DP-series and TRIP-series, has also posed new challenges for the design of the roll passes. The current paper exploits explicitly the finite elements (FE) method and investigates the effect of the roll forming passes design on main redundant deformations, such as longitudinal stains at the edge of the profile, shear strains on strips plane, thickness reduction, and final produced cross section with springback. The profiles discussed are symmetrical V- and U-sections from the AHSS Dual Phase series (DP780). The gradual lowering of the flower pattern design, known as ??downhill pass flow??, is discussed. The calculated decrease in the peak longitudinal strains of up to 28%, and the decrease in thickness of up to 38% are also presented and discussed.     

Experimental study of the effects of rough texture on surface deformation during cold metal forming

Both longitudinal and transverse frictions arising from plane strain during cold metal forming are of crucial importance for the accurate modelling, optimum design, and control of industrial processes. However, the influence of the friction and roughness along the transverse direction has been neglected in much previous research. Oblique roughness textures are considered, and the scale of roughness asperities is enlarged in this study. Four types of prism patterns, in which the angles between the longitudinal direction and the top line of prism are 90°, 60°, 30°, and 0°, and three types of pyramid patterns, in which the top angles are 151.9°, 161.1°, and 168.6°, were designed and manufactured using samples of annealed Al 6060T5. All compression tests were completed in 10 passes, and the total displacement of the pressure head was 5.4 mm. The first five passes were carried out on an Instron 8033 Materials Testing Machine, and the last five passes on a 500-ton compression-testing machine. The surface morphologies of the deformed peak were analysed, and the top areas of the deformed peak were measured. The effects of the angle between the longitudinal direction and the top line of the prism texture or the top angle of the pyramid texture on the surface morphology of the deformed peak are not obvious. The angles have a relatively significant effect on the deformation behaviour of the surface layer during cold metal forming when the deformation is small. The pattern with a top angle of 161.1°, which is the closest to the real value, shows the highest deformation resistance when the displacement of the pressure head is less than 1.2 mm.     

Development of an auto-focus system based on the moiré method

An auto-focus system based on the moiré effect and a feedback control method is presented. First, a collimated laser beam passes through a focusing lens then falls incident on the surface of the sample. The deviation of the angle of the light reflected back is proportional to the defocus distance from the sample. The reflected light then passes through two spiral gratings, producing three types of moiré pattern which can be observed and recorded by a linear CCD. The defocus distance can be derived from the spiral angle in the moiré pattern. The results show that auto-focusing can be achieved by the moiré method for glass and mirror samples in a cycle time of less than 0.1 s.     

River velocity measurements using optical flow algorithm and unoccupied aerial vehicles: A case study

Accurate and reliable measurements of river flow are critical for a multitude of hydrologic engineering applications. However, flow rate measurements using in-situ sensors are uncertain in many applications and physical measurements of velocity may not be practical due to inaccessible sites or flood conditions. Recent advances in remote sensing using unoccupied aerial vehicles have overcome these limitations through non-contact measurements of river velocities; however, existing approaches have several shortcomings, including the need for artificial tracers in the absence of debris and prior knowledge of tracer size, shape, and flow direction. This case study seeks to overcome these shortcomings through the development of a system that utilizes drones, video imaging, and state-of-the-art optical flow algorithms to measure velocity in rivers. This system was applied along Menomonee River in Wauwatosa, WI. To remotely sense river flow, a DJI Matrice 210 RTK drone equipped with a Zenmuse X5S camera was used to capture video. The video data from the drone was analyzed using optical flow algorithms to generate velocity estimations. River velocity was measured directly at point locations using a hand-held velocimeter. Results indicate that the optical flow algorithms estimate the magnitude of surface velocity to within 13–27% of hand-held measurements without the use of artificial seeding. These outcomes suggest that this system could be used as a possible method to measure velocities in rivers.     

A dip-corrected discharge estimation method for a river system

This work proposes a novel dip corrected velocity distribution model in combination with the entropy theory for discharge estimation in a braided river. A modified form of the dip correction factor is derived by considering the topographical complexities and applied for assessing velocity profiles in river cross-sections. The velocity profiles at different verticals are computed by employing Shanon's entropy theory. The depth-averaged velocities at different cross-sections are estimated from the computed vertical velocity profiles and substituted in the area-velocity method for the discharge calculation. The model is applied to two study areas, Majuli and Umananda of the Brahmaputra River, having both simple and braided sections. The validation of the model is performed using the observed discharge data available at the nearby gauge site for low flow condition. Results indicate that the integration of bed rugosity factor in dip corrected velocity distributions improves the accuracy of discharge estimations.     

Effects of heavy metal pollution on pigmented macrophages in kidney of Vardar chub (Squalius vardarensis Karaman)

Pollution with heavy metals may influence the immune system of fish, leading to impairment of their health or even increase their mortality. The fish kidney is one of the first fish organs to be affected by water contamination. Amounts of kidney macrophages (MACs), which are involved in fish immune response, as well as the qualitative and quantitative changes in the pigmented MACs in fish kidney, are used as biomarkers of pollution. Therefore, in this study, we have evaluated relative and total volumes of trunk kidney pigmented MACs, and analyzed the pigments accumulated within them. Fish were sampled from two mining impacted rivers, Kriva and Zletovska, highly contaminated with heavy metals, and from one reference river, Bregalnica, in spring and autumn of 2012. We have observed that main pigments found in kidney MACs of Vardar chub were melanin and lipofuscin/ceroid, as well as that relative volumes of MACs ranged from 0.56 to 1.68%. Moreover, the results showed that relative volumes of pigmented MACs were higher in metal contaminated rivers, especially in autumn season in the Zletovska River, concurrently with extremely high metal exposure. In addition, condition factors and kidney somatic indices were found significantly lower in the Zletovska River in both seasons, autumn and spring, possibly also as a consequence of high water pollution. Our data confirm that increase in relative volumes of pigmented MACs may serve as warning sign of potential heavy metal pollution in aquatic environment.