分水闸站枢纽分水池流态改善措施研究

分水闸站枢纽是集分水闸与泵站为一体的枢纽工程,分水池是分水闸站枢纽的核心进水建筑物,其流态的优劣直接关系到泵站与水闸的安全、高效运行。【目的】深入研究分水池的流动特性及其对泵站、水闸进流条件的影响。【方法】基于物理模型试验,对分水闸站枢纽进水流态进行了研究,分析了分水池产生不良流态的原因,提出了改善分水池流态的整流措施。【结果】分水池流态对泵站及水闸进流条件影响显著,当分水池存在偏流和大范围回流区时,水闸进流存在偏流现象,泵站进水口配水流量不均;分水池发生偏流及壁面脱流的主要原因与分水池扩散段局部体型及来流条件相关;分水池扩散段增设V型底坎后,分水池流态得到显著改善,满负荷运行工况下的泵站前池进水口配水流量均匀度提升了近40%。【结论】V型底坎可以显著增强分水池水流的侧向扩散能力,消除扩散段的壁面脱流,有效改善分水池中的偏流与局部回流。

引汉济渭二期工程黄池沟配水枢纽分水池体型选择浅析

黄池沟配水枢纽是引汉济渭一期调水工程和二期输配水工程连接中枢,分水池是配水枢纽的重要组成部分,其主要功能是将引汉济渭工程调入关中的水量按要求分配给南、北输水干线,保证配水枢纽整体水流过渡平稳、配水准确、运用灵活。分水池充分考虑分水、放空、泄洪的功能需要,初选开敞式矩形与封闭式T型两种型式,通过从施工组织、投资分析、运维管理等方面综合比选,并以模型试验验证,选定采用矩形分水池体型方案。同时,通过模型试验提出分水池的建议运行方式和特征参数,为运行期配水枢纽合理调度和安全运行提供参考依据。

替代分建式消防水池的城市消防水源策略

分析了以分建式消防水池作为城市消防水源存在的问题,并提出了解决的对策,即因地制宜,利用市政给水管网、区域消防水池、非市政水等作为消防水源,以取消或减少分建式消防水池,达到既满足消防要求又节水节能的目的。

浅谈消防水池的建法

本文论述了生活、消防水池(箱)合建的弊病、分建的意义,可供设计时参考。

Spatial Variation of P and N in Water and Sediments of Dianchi Lake, China

Dianchi Lake is one of the most eutrophic lakes in China. In order to understand this eutrophication and to help control the pollution, this research investigated the spatial distribution of Kjeldahl nitrogen (K-N) and total phosphorus(TP) through analysis of bottom water and sediment (3 depths) samples collected at 118 sites around Dianchi Lake. The concentrations of K-N and TP for the lake bottom water in the Caohai part of the lake were much higher than those in the Waihai part, generally decreasing from north to south. In the sediments, the K-N concentration was higher in the Caohai part and the middle of the Waihai part. On the other hand, TP in the sediments was greater in the southern and western parts. Both K-N and TP had similar spatial distributions for the sediment samples of three different depths.Vertically, the K-N and TP concentration in the sediments decreased with an increase in depth. This was evidence that eutrophication and pollution of Dianchi Lake was becoming gradually more severe. Exterior factors including uncontrolled input of domestic and industrial effluents as well as non-point pollution around the lake were the main reasons for serious eutrophication; therefore, controlling these was the first step in reducing eutrophication of Dianchi Lake.

Internal Loads and Bioavailability of Phosphorus and Nitrogen in Dianchi Lake,China

Sediments have a significant influence on the cycling of nutrient elements in lake environments. In order to assess the distribution characteristics and estimate the bioavailability of phosphorus and nitrogen in Dianchi Lake, organic and inorganic phosphorus and nitrogen forms were analysed. The 210 Pb radiometric dating method was employed to study temporal changes in the phosphorus and nitrogen pools in Dianchi Lake. The result show that the total phosphorus(TP) and total nitrogen(TN) were both at high concentrations, ranging from 697.5–3210.0 mg/kg and 1263.7–7155.2 mg/kg, respectively. Inorganic phosphorus(IP) and total organic nitrogen(TON) were the main constituents, at percentages of 59%–78% and 74%–95%, respectively, in the sediments. Spatially, there was a decreasing trend in phosphorus and nitrogen contents from the south and north to the lake centre, which is related to the distribution pattern of local economic production. The burial rates of the various phosphorus and nitrogen forms increased in same spatially and over time. Particularly in the past two decades, the burial rates doubled, with that TN reached to 1.287 mg/(cm^2·yr) in 2014. As the most reactive forms, nitrate nitrogen(NO_3-N) and ammonia nitrogen(NH_4-N) were buried more rapidly in the south region, implying that the potential for releasing sedimentary nitrogen increased from north to south. Based on their concentrations and burial rates, the internal loads of phosphorus and nitrogen were analysed for the last century. A TP pool of 71597.6 t and a TN pool of 81191.7 t were estimated for Dianchi Lake. Bioavailable phosphorus and nitrogen pools were also estimated at 44468.0 t and 5429.7 t, respectively, for the last century.

Recent advances in one-dimensional nanostructures for energy electrocatalysis

Catalysts play decisive roles in determining the energy conversion efficiencies of energy devices.Up to now,various types of nanostructured materials have been studied as advanced electrocatalysts.This review highlights the application of one‐dimensional(1D)metal electrocatalysts in energy conversion,focusing on two important reaction systems-direct methanol fuel cells and water splitting.In this review,we first give a broad introduction of electrochemical energy conversion.In the second section,we summarize the recent significant advances in the area of 1D metal nanostructured electrocatalysts for the electrochemical reactions involved in fuel cells and water splitting systems,including the oxygen reduction reaction,methanol oxidation reaction,hydrogen evolution reaction,and oxygen evolution reaction.Finally,based on the current studies on 1D nanostructures for energy electrocatalysis,we present a brief outlook on the research trend in 1D nanoelectrocatalysts for the two clean electrochemical energy conversion systems mentioned above.

In-situ formation of cobalt phosphide nanoparticles confined in three-dimensional porous carbon for high-performing zinc-air battery and water splitting

The rational design of efficient and stable carbon-based electrocatalysts for oxygen reduction and oxygen evolution reactions is crucial for improving energy density and long-term stability of rechargeable zinc-air batteries(ZABs).Herein,a general and controllable synthesis method was developed to prepare three-dimensional(3D)porous carbon composites embedded with diverse metal phosphide nanocrystallites by interfacial coordination of transition metal ions with phytic acid-doped polyaniline networks and subsequent pyrolysis.Phytic acid as the dopant of polyaniline provides favorable anchoring sites for metal ions owing to the coordination interaction.Specifically,adjusting the concentration of adsorbed cobalt ions can achieve the phase regulation of transition metal phosphides.Thus,with abundant cobalt phosphide nanoparticles and nitrogen-and phosphorus-doping sites,the obtained carbon-based electrocatalysts exhibited efficient electrocatalytic activities toward oxygen reduction and evolution reactions.Consequently,the fabricated ZABs exhibited a high energy density,high power density of 368 mW cm^(-2),and good cycling/mechanical stability,which could power water splitting for integrated device fabrication with high gas yields.

Dye-sensitized photoanode decorated with pyridine additives for efficient solar water oxidation

Splitting water into hydrogen and oxygen by dye-sensitized photoelectrochemical cell(DSPEC)is a promising approach to solar fuels production.In this study,a series of pyridine derivatives as surface additives were modified on a molecular chromophore and water oxidation catalyst co-loaded TiO_(2)photoanode,TiO_(2)|RuP,1(RuP=Ru(4,4′-(PO3H2)2-2,2′-bipyridine)(2,2′-bipyridine)2,1=Ru(bda)(L)2,(bda=2,2′-bipyridine-6,6′-dicarboxylate,L=10-(pyridin-4-yloxy)decyl)phosphonic acid).The addition of pyridine additives was found to result in up to 42%increase in photocurrent.Under simulated sun-light irradiation,TiO_(2)|RuP,1,P1(P1=4-Hydroxypyridine)produced a photocurrent density of 1 mA/cm2 at a bias of 0.4 V vs.NHE in acetate buffer.Moreover,the observed photocurrents are correlated with the electron-donating ability of the substituent groups on pyridine ring.Transient absorption measurements and electrochemical impedance spectroscopy revealed that surface-bound pyridine can effectively retard the back-electron transfer from the TiO_(2)conduction band to the oxidized dye,which is a major process responsible for energy loss in DSPECs.

Electrochemical creation of surface charge transfer channels on photoanodes for efficient solar water splitting

Electrochemical treatment is a popular and efficient method for improving the photoelectrochemical performance of water‐splitting photoelectrodes.In our previous study,the electrochemical activation of Mo‐doped BiVO_(4) electrodes was ascribed to the removal of MoO_(x) segregations,which are considered to be surface recombination centers for photoinduced electrons and holes.However,this proposed mechanism cannot explain why activated Mo‐doped BiVO_(4) electrodes gradually lose their activity when exposed to air.In this study,based on various characterizations,it is suggested that electrochemical treatment not only removes partial MoO_(x) segregations but also initiates the formation of H_(y)MoO_(x) surface defects,which provide charge transfer channels for photogenerated holes.The charge separation of the Mo‐doped BiVO_(4) electrode was significantly enhanced by these charge transfer channels.This study offers a new insight into the electrochemical activation of Mo‐doped BiVO_(4) photoanodes,and the new concept of surface charge transfer channels,a long overlooked factor,will be valuable for the development of other(photo)electrocatalytic systems.

Heavy Metal Analysis in Groundwater in the Vicinity of Distillery Spent Wash Evaporation Ponds

The study was conducted to assess the effect of evaporation ponds of an ethanol distillery spent wash on groundwater, with a reference to heavy metal contamination. The distillery discharging 11,880 m3 spent wash per day is extremely loaded with minerals and chemical oxygen demanding organic substances. The groundwater around the evaporation ponds is used for drinking and irrigation purposes. Thirty-five representative samples （three spent wash, two drainage water and 30 groundwater） were examined for 13 different parameters： pH, TDS （total dissolved solids）, COD （chemical oxygen demand）, the heavy metal Cd, Co, Cr, Cu, Fe, Mn, Ni, Zn, Pb and As concentrations. The physico-chemical parameters were found in following range pH 7.2-7.7 ＆ 6.8-7.7, TDS 24,448-28,608 mg/L ＆ 302-4,406 mg/L, COD 20,080-24,320 mg/L ＆ 0.0-53 mg/L, Cd 190-140 μg/L ＆ 1.5-8.7 μg/L, Co 1,240-1,987 μg/L ＆ 20.5-87.2 μg/L, Cr 1,020-1,330 μg/L ＆ 14.4-38.1 μg/L, Cu 5,200-6,300 μg/L ＆ 15.0-109.3 μg/L, Fe 2,910-3,242 μg/L ＆ 0-860 μg/L, Mn 49,900-59,500 μg/L ＆ 16.3-138.7 μg/L, Ni 1,430-1,760 μg/L ＆ 8.0-107.7 μg/L, Zn 3,359-5,250 μg/L ＆ 0.0-850 μg/L, Pb 8.9-9.8 μg/L ＆ BD （below detection）-8.7 μg/L, As 5.0 μg/L ＆ BD-10.0 μg/L for spent wash and groundwater samples, respectively. The drainage water samples had parameters within limits for industrial effluents. The spent wash samples contained metal ions higher than the permissible limits for industrial effluents and the samples of groundwater collected around the evaporation ponds contained higher concentrations of metal ions as compared to samples collected away from the evaporation ponds. Coefficient of correμtion among 11 parameters was calcuμted and contamination index was also determined, 33.3% of groundwater samples mostly collected around evaporation ponds had a contamination index above 3 and are considered extremely polluted.