基于关键控制因子的地下水补给源判别方法

为了在缺乏同位素数据时更简单准确地识别地下水补给源,使用因子分析法对水化学数据进行降维,利用层次分析法与熵值法加以辅佐确定关键控制因子,结合判别分析理论构建地下水补给源判别模型,提出一种地下水补给来源识别的新方法。结合日照市五莲地区地下水水化学数据,选取TDS、Ca~(2+)、Mg~(2+)、K~+、Na~+、Cl~-、SO_2~(4-)、HCO_3~-、NO_3~-为判别指标,确定了使该地区丰水期碎屑岩类孔隙裂隙水与基岩裂隙水水化学特征发生改变的外部补给水源为松散岩类孔隙水,对该地区的水资源开发利用具有指示意义。     

井陉地区岩溶地下水水化学特征及其影响因素分析

基于2018年9月采集的24件丰水期地下水样品分析测试结果,综合运用数理统计、Piper三线图、相关性分析、Gibbs图和主要离子比值法等分析井陉地区岩溶地下水水化学特征及其影响因素。结果表明,岩溶地下水的主要阴阳离子为HCO3-、SO24-、Ca2+,水化学类型主要为SO4·HCO3-Ca、HCO3·SO4-Ca型;局部地区出现地下水点状污染,超标水点分布在工矿企业和农田等地区,主要影响指标为总硬度、硫酸盐和硝酸盐;地下水水化学主要受水岩作用控制,但也受人为因素、地下水径流方向及地表水影响。其中水岩作用主要以碳酸盐岩、硫酸盐岩和岩盐矿物风化溶解为主,也存在不同程度的阳离子交换作用;人为因素主要以工矿业污染为主。研究结果为井陉地区岩溶地下水污染防治提供了理论参考。     

阳泉市娘子关岩溶地下水水化学特征及其成因

针对娘子关泉域水化学分析不能即时评价且偏主观性的问题,加入离子空间分布图,对娘子关泉域岩溶地下水的13个水化学特征指标运用描述性统计、水化学类型、TDS和总硬度分布图等进行分析,并辅助以Pearson相关分析探究其成因。结果表明,个别水样超过地下水环境质量标准,Fe~(3+)、Na~+具有较大空间变化,其他元素相对稳定;除少部分为微咸水和软水、微硬水、硬水,大部分地区为淡水和极硬水;地下水水化学类型以HCO_3-Ca·Mg、SO_4·HCO_3-Ca、SO_4·HCO_3-Ca·Mg型为主,部分补给区和径流区已转变为硫酸盐类型为主的水。该水化学特征成因主要受工矿产业影响,其次受水岩作用和农业、生活污染的影响。     

基于Arcgis的北京市大兴区地下水水质评价研究

北京市大兴区社会供水以地下水为主,对该区浅层地下水进行水质评价,对指导区域地下水的开发利用和保障居民饮水安全十分必要。在以往研究成果的基础上,利用北京市大兴区实测地下水水样数据进行分析研究。选取66个具有代表性的浅层地下水水样,运用标准指数法和综合指数法对研究区地下水进行水质评价和统计分析。结果表明:研究区超标严重的水质因子主要是NO3-、Fe3+、总硬度和TDS;研究区水质总体较差,Ⅱ类水质区占总面积的40.5%,Ⅳ类水质区占总面积的30.3%,Ⅴ类水质区占总面积的29.2%。地下水化学类型分类结果表明,水化学类型以HCO3-Ca·Mg·Na型为主。     

淇县地区地下水化学特征及其影响因素分析

为了解淇县地区地下水化学特征,选取57个水样数据,运用统计分析、相关性分析以及Gibbs方法分析了淇县地区地下水水化学特征。结果表明,淇县地区从山区到平原地下水更新速度逐渐变慢,EC逐渐升高;TDS与Na~+、Cl~-、SO_4~(2-)、HCO_3-相关性很高;深层地下水整体呈HCO_3-Ca·Mg型水,浅层地下水化学整体呈水平分带性,从淇河上游HCO_3-Ca型水到淇河中游的HCO_3-Ca·Mg型水再过渡到淇河下游的HCO_3·Cl-Ca·Mg和HCO_3·SO4-Ca·Mg·Na型水;局部地区出现地下水点状污染。淇县地区水化学主要受岩性控制,局部地区受水动力条件及人为因素影响。研究成果可为淇县地区地下水污染防治提供参考。     

东阿县沿黄区孔隙地下水化学特征及成因分析

基于东阿县牛角店镇、乐平铺镇等地区38组孔隙水样品和3组黄河水样品,采用水化学离子比法和氢氧同位素分析法,系统分析了东阿县沿黄区孔隙水化学特征的形成机理及黄河水对孔隙水的影响。结果表明,研究区孔隙地下水以HCO₃-Na型为主,含水层中主要发生硅酸盐岩溶解和碳酸岩溶解过程;黄河水入渗、大气降水的入渗和水-岩相互作用是区内地下水化学成因的主导因素;区内地下水化学与同位素特征反映出研究区内黄河影响带范围在18 km以内,影响带范围内地下水参与外界循环不积极,主要受黄河水的补给,地下水化学组成主要受黄河水和水-岩相互作用的影响,在影响带范围外地下水化学组成受到大气降水的影响程度增大。     

桐梓隧道岩溶地下水化学特征及水质评价

为分析桐梓隧道岩溶地下水水化学特征和水质情况,运用Piper三线图、Gibbs模型、离子比例系数及Pearson相关系数矩阵等方法探究其类型及成因,并结合模糊综合评价法对地下水水质进行分类评价。结果表明,研究区地下水中Mg~(2+)、Ca~(2+)、HCO_3~-占主要优势,Mn、As、Se的含量极低;地下水化学类型以HCO_3-Ca、HCO_3·SO_4-Ca·Mg型水为主;水化学形成主要来源于岩石风化碳酸盐岩(如方解石、白云石),少部分来源于硅酸盐岩、石膏、钠长石等矿物溶滤,大气降水和人为因素也有一定影响,表现为隧道施工加速了岩石溶蚀风化;模糊综合评价表明研究区地下水水质良好,以Ⅰ、Ⅲ类为主。研究结果可为隧道区地下水水资源保护及利用提供参考。     

张掖盆地地下水锶元素地球化学特征研究

为研究张掖盆地地下水中锶元素的地球化学特征,以盆地内15个钻孔中28组地下水水样的化学测试数据为基础,刻画盆地内地下水中Sr~(2+)的分布规律,并分析了Sr~(2+)与地下水中主要指标的相关性。结果表明,地下水Sr~(2+)浓度沿地下水的流动路径呈现出明显的水化学特征演化规律,总体上表现为山前冲洪积扇区浅层和深层地下水Sr~(2+)浓度普遍大于中部细土平原区的浅层和深层地下水Sr~(2+)浓度,SO_4·HCO_3型地下水中Sr~(2+)浓度大于HCO_3·SO_4型地下水中Sr~(2+)浓度值,浅层地下水中Sr~(2+)浓度大于深层地下水中Sr~(2+)浓度。Sr~(2+)浓度与TDS、TH及Ca~(2+)、Na~+、Mg~(2+)、HCO_3~-、SO_4~(2-)浓度正相关,表明地下水中Sr~(2+)主要来自水—岩相互作用过程中含锶矿物的溶解。研究成果开拓了地下水循环与演化研究的思路,提供了一种分析水文地质问题的新方法。     

合理开发关中地区地下水资源的几点建议

通过对关中地区地下水资源的开发利用现状和潜力分析,提出了合理开发关中地区地下水资源的因地制宜地利用浅层地下水;积极利用基岩孔隙裂隙水、岩溶水和傍河地下水;解决地下水超采引发的环境地质问题;有计划地关闭部分承压水井等建设性建议。     

南京地下水资源在未来城市供水中的作用

南京是以地表水作为主要水源的城市，地下水只在城市供水中占很小一部分，与自来水相比，地下水含有多种人体必需的微量元素；与纯净水等相比，矿泉水为最好的饮用水。最重要的一点，地下水具有地表水所无法代替的优质、恒温、动态变化稳定和不易污染等特点，合理利用地下水资源，发挥地下水在城市供水中的重要补充作用，对南京经济的可持续发展将起到积极作用。能源研究与利用２０００年第１期１　地下水资源概况南京市的地下水有孔隙水、岩溶水及裂隙水三类。孔隙水分布于长江及秦淮河、滁河的古河道区，含水顶板埋深为１～６ｍ，含水层厚…     

Ash-forming elements in four Scandinavian wood species. Part 1: Summer harvest

Woody biomass in Finland and Sweden comprises mainly four wood species: spruce, pine, birch and aspen. To study the ash, which may cause problems for the combustion device, one tree of each species were cut down and prepared for comparisons with fuel samples. Well-defined samples of wood, bark and foliage were analyzed on 11 ash-forming elements: Si, Al, Fe, Ca, Mg, Mn, Na, K, P, S and Cl. The ash content in the wood tissues (0.2–0.7%) was low compared to the ash content in the bark tissues (1.9–6.4%) and the foliage (2.4–7.7%). The woods’ content of ash-forming elements was consequently low; the highest contents were of Ca (410–1340 ppm) and K (200–1310), followed by Mg (70–290), Mn (15–240) and P (0–350). Present in the wood was also Si (50–190), S (50–200) and Cl (30–110). The bark tissues showed much higher element contents; Ca (4800–19,100 ppm) and K (1600–6400) were the dominating elements, followed by Mg (210–2400), P (210–1200), Mn (110–1100) and S (310–750), but the Cl contents (40–330) were only moderately higher in the bark than in the wood. The young foliage (shoots and deciduous leaves) had the highest K (7100–25,000 ppm), P (1600–5300) and S (1100–2600) contents of all tissues, while the shoots of spruce had the highest Cl contents (820–1360) and its needles the highest Si content (5000–11,300). This paper presented a new approach in fuel characterization: the method excludes the presence of impurities, and focus on different categories of plant tissues. This made it possible to discuss the contents of ash element in a wide spectrum of fuel-types, which are of large importance for the energy production in Finland and Sweden.     

NEXT GENERATION ENGINEERED MATERIALS FOR ULTRA SUPERCRITICAL STEAM TURBINES

正1 ABSTRACT To reduce the effect of global warming on our climate,the levels of CO2emissions should be reduced.One way to do this is to increase the efficiency of electricity production from fossil fuels.This will in turn reduce the amount of CO2emissions for a given power output.Using US practice for efficiency calculations,then a move from a typical US plant running at 37%efficiency to a 760℃/38.5 MPa(1 400/5 580 psi)plant running at 48%efficiency would reduce CO2emissions by 170kg/MW.hr or 25%.     

Aerodynamic performance effects of leading-edge geometry in gas-turbine blades

The purpose of this paper is to illustrate the advantages of the direct surface-curvature distribution blade-design method, originally proposed by Korakianitis, for the leading-edge design of turbine blades, and by extension for other types of airfoil shapes. The leading edge shape is critical in the blade design process, and it is quite difficult to completely control with inverse, semi-inverse or other direct-design methods. The blade-design method is briefly reviewed, and then the effort is concentrated on smoothly blending the leading edge shape (circle or ellipse, etc.) with the main part of the blade surface, in a manner that avoids leading-edge flow-disturbance and flow-separation regions. Specifically in the leading edge region we return to the second-order (parabolic) construction line coupled with a revised smoothing equation between the leading-edge shape and the main part of the blade. The Hodson–Dominy blade has been used as an example to show the ability of this blade-design method to remove leading-edge separation bubbles in gas turbine blades and other airfoil shapes that have very sharp changes in curvature near the leading edge. An additional gas turbine blade example has been used to illustrate the ability of this method to design leading edge shapes that avoid leading-edge separation bubbles at off-design conditions. This gas turbine blade example has inlet flow angle 0°, outlet flow angle −64.3°, and tangential lift coefficient 1.045, in a region of parameters where the leading edge shape is critical for the overall blade performance. Computed results at incidences of −10°,   −5°,   +5°,   +10° are used to illustrate the complete removal of leading edge flow-disturbance regions, thus minimizing the possibility of leading-edge separation bubbles, while concurrently minimizing the stagnation pressure drop from inlet to outlet. These results using two difficult example cases of leading edge geometries illustrate the superiority and utility of this blade-design method when compared with other direct or inverse blade-design methods.     

Hydrogen production by steam-gasification of carbonaceous materials using concentrated solar energy – V. Reactor modeling,optimization, and scale-up

A chemical reactor for the steam-gasification of carbonaceous particles (e.g. coal, coke) is considered for using concentrated solar radiation as the energy source of high-temperature process heat. A two-phase reactor model that couples radiative, convective, and conductive heat transfer to the chemical kinetics is applied to optimize the reactor geometrical configuration and operational parameters (feedstock's initial particle size, feeding rates, and solar power input) for maximum reaction extent and solar-to-chemical energy conversion efficiency of a 5 kW prototype reactor and its scale-up to 300 kW. For the 300 kW reactor, complete reaction extent is predicted for an initial feedstock particle size up to 35 μm at residence times of less than 10 s and peak temperatures of 1818 K, yielding high-quality syngas with a calorific content that has been solar-upgraded by 19% over that of the petcoke gasified.     

Contents in Volume 23,2014

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汽轮机数字电液调节系统挂闸异常的技术完善

分析了200MW汽轮机数字电液调节系统在运行中存在的挂闸异常问题,采取了相应的技术处理措施,且运行实践效果良好。     

新型高压共轨ECU升压模块的数字化开发与优化

为了提高喷油器电磁阀的响应速率,提出了一种基于CPLD(复杂可编程逻辑器件)应用于高压共轨ECU的数字升压模块。鉴于该升压电路结构参数多,其升压电压的恢复响应要求高等特征,基于Pspice建立了升压电路的仿真模型,研究了不同电路参数下升压模块的输出特性,全面优化了该升压模块的性能。结果显示,该升压模块的最大转换效率可以达90%以上。在柴油发动机上对ECU的试验表明,升压电压最大波动不超过10%,其恢复时间仅为1.3ms,功率管最大温升仅为41℃,满足整机运行范围内ECU的需求。     

Trace metal chemistry and silicification of microorganisms in geothermal sinter, Taupo Volcanic Zone, New Zealand

As part of a pilot study investigating the role of microorganisms in the immobilisation of As, Sb, B, Tl and Hg, the inorganic geochemistry of seven different active sinter deposits and their contact fluids were characterised. A comprehensive series of sequential extractions for a suite of trace elements was carried out on siliceous sinter and a mixed silica-carbonate sinter. The extractions showed whether metals were loosely exchangeable or bound to carbonate, oxide, organic or crystalline fractions. Hyperthermophilic microbial communities associated with sinters deposited from high temperature (92–94°C) fluids at a variety of geothermal sources were investigated using SEM. The rapidity and style of silicification of the hyperthermophiles can be correlated with the dissolved silica content of the fluid. Although high concentrations of Hg and Tl were found associated with the organic fraction of the sinters, there was no evidence to suggest that any of the heavy metals were associated preferentially with the hyperthermophiles at the high temperature (92–94°C) ends of the terrestrial thermal spring ecosystems studied.     

Assessment methods of material ageing using Sdobyrev''s creep rupture model

The physical aspects of the activation energy, in higher and high temperatures, of the metal creep process were examined. The research results of creep-rupture in a uniaxial stress state and the criterion of creep-rupture in biaxial stress states, at two temperatures, are then presented. For these studies creep-rupture, taking case iron as an example the energy and pseudoenergy activation was determined. For complex stress states the criterion of creep-rupture was taken to be Sdobyrev's, i.e. σ_red = σ₁ β + (1 − β)σ_i, where: σ₁-maximal principal stress, σ_i-stress intensity, β-material constant (at variable temperature β = β(T)). The methods of assessment of the material ageing grade are given in percentages of ageing of new material in the following mechanical properties: 1) creep strength in uniaxial stress state, 2) activation energy in uniaxial stress state, 3) criterion creep strength in complex stress states, 4) activation pseudoenergy in complex stress states. The methods 1) and 3) are the relatively simplest because they result from experimental investigations only at nominal temperature of the structure work, however, for methods 2) and 4) it is necessary to perform the experimental investigations at least at two temperatures.     

Production of hydrogen from sewage biosolids in a continuously fed bioreactor: Effect of hydraulic retention time and sparging

Hydrogen was produced from primary sewage biosolids via mesophilic anaerobic fermentation in a continuously fed bioreactor. Prior to fermentation the sewage biosolids were heated to 70 °C for 1 h to inactivate methanogens and during fermentation a cellulose degrading enzyme was added to improve substrate availability. Hydraulic retention times (HRT) of 18, 24, 36 and 48 h were evaluated for the duration of hydrogen production. Without sparging a hydraulic retention time of 24 h resulted in the longest period of hydrogen production (3 days), during which a hydrogen yield of 21.9 L H₂ kg⁻¹ VS added to the bioreactor was achieved. Methods of preventing the decline of hydrogen production during continuous fermentation were evaluated. Of the techniques evaluated using nitrogen gas to sparge the bioreactor contents proved to be more effective than flushing just the headspace of the bioreactor. Sparging at 0.06 L L min⁻¹ successfully prevented a decline in hydrogen production and resulted in a yield of 27.0  L H₂ kg⁻¹ VS added, over a period of greater than 12 days or 12 HRT. The use of sparging also delayed the build up of acetic acid in the bioreactor, suggesting that it serves to inhibit homoacetogenesis and thus maintain hydrogen production.