High Pressure-Differential Thermal Analysis and Ultrasonic Wave Amplitude Analysis of Ice-Water Equilibrium at 1.5-5.0 GPa

Water is the most active component in all geological systems. It has an importanteffect on the physical properties of minerals and melts. It also plays a key role in the evolutionof the Earth. Accurate thermodynamics data on water are currently confined to pressures below1.0 GPa and temperatures below 900℃. Presented in this paper are new data available on theP-T properties of water at pressures up t0 5. 0 GPa, developed from differential thermal analysis and ultrasonic wave amplitude analysis. It has been found that there may exist anotherternary point at 3. 0 GPa and that ultrasonic wave amplitude change of ice-water transitionshows two inflection points above 2. 0 GPa, consistent with the two peaks of differential thermal curves above 2. 0 GPa. It may be a new phenomenon which needs further study.

Thermodynamic Consistency Test for Binary Gas ＋ Water Equilibrium Data at Low and High Pressures

Phase equilibrium in binary gas + water mixtures over wide ranges of temperatures and pressures are modeled and tested for thermodynamic consistency. For modeling, the Peng-Robinson equation of state was used and the Wong-Sandler mixing rules were incorporated into the equation of state parameters. In the Wong-Sandler mixing rules the van Laar model for the excess Gibbs energy was applied. In addition, a reasonable and flexible method is applied to test the thermodynamic consistency of pressure-temperature-concentration(P-T-x) data of these binary mixtures.Modeling is found acceptable in all cases, meaning that deviations in correlating the pressure and the gas phase concentration are low. For all cases the thermodynamic consistency method gives a clear conclusion about consistency or inconsistency of a set of experimental P-T-x data.

High pressure-differential thermal analysis of ice-water equilibrium at 1.5-5.0 GPa

It is well known that trace amount of water has important effects on the physical properties of minerals and melts. Strength and viscosity decrease, diffusion rate and electrical conductivity increase, seismic waves attenuate and liquidus temperatures are lowered by the addition of water. The effects make water one of the most active components of any geological system with implications for the evolution and dynamics of the earth.

Study on the mechanism of isotope fractionation in soil water during the evaporation process under equilibrium condition

In this study, with the method of vacuum extraction, two evaporative processes of soil water and free water under equilibrium condition were simulated. For each sample,water vapor was condensed by liquid nitrogen and was collected in four time intervals. From the analysis of hydrogen and oxygen isotopic compositions of the water collected at different times, it was discovered that the isotope fractionation of soil water also follows the mode, which is just the same as the evaporative process of free water. The relationship between the stable hydrogen and oxygen isotopes in residual water showed that the simulative evaporation line was close to the global meteoric water line (GMWL) under the equilibrium condition at about 20℃. Comparison of the two types of evaporative processes indicated that the isotope fractionation and evaporation velocity of soil water were only slightly modified by the Van der Waals force.

Experimental adsorption equilibrium study and comparison of zeolite with water and ethanol for cooling systems

Two adsorption refrigeration working pairs of zeolite with water and ethanol were studied and the parameters of Dubinin-Astakhov model were regressed using the experimental data of equilibrium. The coefficient of heterogeneity varied from 1.305 to 1.52 for the zeolite-water pair and from 1.73 to 2.128 for zeolite-ethanol pair. The maximum adsorption capacity varied from 0.315 to 0.34 for zeolite-water and 0.23 to 0.28 for zeolite-ethanol, respectively. The results showed that the zeolite-water pair is suitable for solar energy cooling not only because of the high latent heat of vaporization of water but also because of the better equilibrium performance. On the other hand, zeolite-ethanol gives a high adsorption capacity at high regeneration tem-perature, which means it can be used in heat engine systems like buses and cars.

Catalytic Effect of Activated Carbon and Activated Carbon Fiber in Non-Equilibrium Plasma-Based Water Treatment

Catalysis and regeneration efficiency of granular activated carbon （GAC） and activated carbon fiber （ACF） were investigated in a non-equilibrium plasma water treatment reactor with a combination of pulsed streamer discharge and GAC or ACF. The experimental results show that the degradation efficiency of methyl orange （MO） by the combined treatment can increase 22% （for GAC） and 24% （for ACF） respectively compared to pulsed discharge treatment alone, indicating that the combined treatment has a synergetic effect. The MO degradation efficiency by the combined treatment with pulsed discharge and saturated GAC or ACF can increase 12% and 17% respectively compared to pulsed discharge treatment alone. Both GAC and ACF show catalysis and the catalysis of ACF is prominent. Meanwhile, the regeneration of GAC and ACF are realized in this process. When H202 is introduced into the system, the utilization efficiency of ozone and ultraviolet light is improved and the regeneration efficiency of GAC and ACF is also increased.

Liquid-Liquid Equilibrium for 1-Butanol-Water-KF and 1-Butanol-Water-K_2CO_3 Systems

KF or K2CO3 was added into the 1-butanol-water system and two phases were formed： water-rich phase （water phase） and 1-butanol-rich phase （1-butanol phase）. The liquid liquid equilibrium （LLE） data for 1-butanol-water-KF and 1-butanol-water-K2CO3 systems were measured at 25℃ and showed that 1-butanol phase contained negligible salt and water phase contained negligible 1-butanol when the concentrations of KF and K2CO3 in the water phase were equal to or higher than 27.11% and 31.68% , respectively. Thus water could be separated efficiently from 1-butanol-water by adding KF or K2CO3 into the system. A theoretical calculation of LLE data was calculated by using the Pitzer theory to get water activity in the water phase, and by the models, such as the Wilson, NRTL or the UNIQUAC for the 1-butanol phase. For 1-hutanol-water-KF system, the experimental data were found in good agreement with the calculated results by using Pitzer theory and Wilson equa tion, while for 1-butanol-water-K2CO3 system, the experimental data were found in good agreement with the calculated results by using Pitzer theory and UNIQUAC eauation.

Soil-water characteristics of Gaomiaozi bentonite by vapour equilibrium technique

Soil-water characteristics of Gaomiaozi(GMZ)Ca-bentonite at high suctions(3–287MPa)are measured by vapour equilibrium technique.The soil-water retention curve(SWRC)of samples with the same initial compaction states is obtained in drying and wetting process.At high suctions,the hysteresis behaviour is not obvious in relationship between water content and suction,while the opposite holds between degree of saturation and suction.The suction variation can change its water retention behaviour and void ratio.Moreover,changes of void ratio can bring about changes in degree of saturation.Therefore,the total change in degree of saturation includes changes caused by suction and that by void ratio.In the space of degree of saturation and suction,the SWRC at constant void ratio shifts to the direction of higher suctions with decreasing void ratio.However,the relationship between water content and suction is less affected by changes of void ratio.The degree of saturation decreases approximately linearly with increasing void ratio at a constant suction.Moreover,the slope of the line decreases with increasing suction and they show an approximately linear relationship in semi-logarithmical scale.From this linear relationship,the variation of degree of saturation caused by the change in void ratio can be obtained.Correspondingly,SWRC at a constant void ratio can be determined from SWRC at different void ratios.

Henry’s Equilibrium Partitioning between Ground Water and Soil Air: Predictions versus Observations

Humans spend 64% - 94% of their time indoors;therefore, indoor air quality is very important for potential exposure to volatile organic compounds (VOC). The source of VOC in the subsurface may come from accidental or intentional releases, leaking landfills or leaking underground and above-ground storage tanks. Once these contaminants are present near or beneath buildings, they may move as a vapour through soil gas and enter the building. A large number of vapour intrusion (VI) algorithms have been published in peer-reviewed publications that link indoor VOC concentrations to the contamination of soils. These models typically include phase partitioning calculations of VOC based on Henry’s law to estimate the concentration of a particular contaminant in soil gas. This paper presents the results from a series of laboratory experiments concerning the use of the Henry’s Law constant for the calculation of toluene concentrations in equilibrium between ground water and soil air. A series of column experiments were conducted with various toluene concentrations in artificial (ground) water to contrast the predicted and observed (soil) air concentrations. The experiments which exclude soil material show a toluene fugacity behaviour roughly in line with Henry’s law whereas the experiments which include soil material result in equilibrium soil concentrations which were around one order-of-magnitude lower than was expected from a Henry Law-based estimation. It is concluded that for toluene inclusion of Henry’s Law in VI algorithms does not provide an adequate description of volatilisation in soils and may lead to an overestimation of health risk. Instead, a model based on a simple description of the relevant intermolecular interactions could be explored.

Na^(+),K^(+)//CO_(3)^(2-),SO_(4)^(2-)-H_(2)O四元水盐体系相平衡综合实验设计

针对相平衡理论知识抽象难懂,相律、相图等内容难教难学的问题,设计了四元水盐体系相平衡综合实验。采用等温溶解平衡法研究了353~373 K下交互四元体系Na^(+),K^(+)//CO_(3)^(2-),SO_(4)^(2-)-H_(2)O的固液相平衡,并绘制出等温干基相图和对应水图,确定硫酸钠相区随着温度的增加而上移。依据相图指导碱灰溶解-蒸发结晶工艺设计,解决了高CO_(3)^(2-)浓度下结晶参数的优化问题,实现Na2SO4在高温下溶解,随后降温结晶析出的循环回收过程。该实验将相平衡数据的测量、相图的绘制、相图的分析融合一体,有利于增强学生用相平衡基本理论解决工程问题的能力,实现对理论知识的融会贯通,激发其科研兴趣和探索精神。

Theory of an Optimal Dynamical Water Resource Management Policy

Water markets even though not perfect and require a lot of effort to establish are considered as a robust tool to address water management issues around the world. However, the existing literature does not provide an optimal water resource management policy. To create a perfect water market, the government needs to identify the potential number of suppliers/producers and consumers of water against various extraction/supply/production rates of water, i.e., to identify a supply and a demand curve for number of suppliers/producers of water against each production rate in economy. This article presents a theory which is practically applicable for an optimal dynamical water resource management policy (JEL H20, H23, H27).

黄河流域河南段水资源空间均衡研究

基于水资源负载指数、水土资源匹配系数和用水效益系数等测算模型,研究了黄河流域河南段2011—2020年水资源空间均衡性.结果表明,黄河流域河南段8市水资源负载指数大致呈波动增长趋势且远大于10,水资源利用程度很高,基尼系数为0.31;水土资源匹配系数大致呈波动下降趋势且平均值为0.33,水土匹配程度较低,基尼系数为0.28;用水效益系数呈稳步上升趋势,单方水GDP产值为208元,用水效益与经济发展水平相对合理,基尼系数为0.32;水资源空间均衡系数平均值为0.55,空间均衡等级为Ⅲ级,属于一般失衡.基于此,合理配置水资源、提高用水效率、提前规划引水调水等有利于促进黄河流域河南段社会经济和水资源利用空间均衡发展.

黄河流域“水资源-生态保护-高质量发展”空间均衡性诊断

为促进黄河流域空间均衡发展,在测算黄河流域9个省区水资源可承载水平、经济社会发展水平以及生态保护水平的基础上,分析了各省区内部水资源、生态环境和经济社会3个子系统间的耦合协调发展水平,并分别以水与经济均衡、水与生态均衡、经济与生态均衡为子目标,构建了空间均衡性诊断模型,对黄河流域相邻“省区对”进行了空间均衡性诊断,反向追踪各“省区对”空间不均衡的原因。结果显示:除宁夏、甘肃外,黄河流域其他省区内部3个子系统间均已达到初级或中级协调发展阶段;黄河流域上游和下游的相邻“省区对”分别通过了均衡性判别;宁夏、甘肃、山西和内蒙古4个省区严重影响了省区间的均衡性,抑制了黄河流域整体的空间均衡发展。

涟水高沟地区承压地下水可更新性研究

为合理开发利用和保护地下水资源,评价区域地下水可更新性成为当前首要解决的问题。本文从定性和定量两个角度进行分析研究,首先从区域水文地质条件与地下水水动力等方面,进行地下水系统划分及特征研究,分析含水层空间结构及补径排条件;其次在收集利用以往测试资料基础上,通过现场采样分析,开展不同水体环境同位素特征研究;最后利用水均衡法计算地下水可更新能力指标。研究结果表明:涟水高沟地区承压水具备地下水补给通道,主要接受上游山区侧向径流补给,且在开发利用过程中不会引发地面沉降等环境地质问题;地下水水龄2万年左右,水循环更新周期上千年,可认为其具有一定的更新能力,不属于难以更新的地下水;同时,地下水的合理开发利用有助于加快地下水循环速率,进一步提高地下水更新能力。

基于极限平衡理论的陷落柱防水煤柱留设研究

为有效治理含水陷落柱的导水致灾现象,以平朔井工一矿4108工作面为背景,根据井下实际地质生产条件计算防水煤柱极限平衡宽度,从理论层面初步确定防水煤柱留设宽度,同时利用UDEC软件对不同宽度的煤柱塑性破坏进行数值模拟分析。模拟结果表明:当煤柱宽度达到40 m时,煤柱内的屈服区和周边裂隙带基本保持稳定,根据煤柱稳定性对弹性区宽度应大于14 m的要求,防水煤柱宽度应留设40 m;在煤柱宽度与弹性区宽度关系上,煤柱内弹性区的宽度随着煤柱宽度的增加而增加,当煤柱宽度大于40 m时,煤柱内屈服区与塑性区的宽度已基本稳定。4108工作面采用设计的绕过陷落柱方案,优化了绕过陷落柱工序,有效降低了煤炭资源的损失。

基于水资源空间均衡的“四水四定”调控模型构建

为实现未来不同时间尺度下的水资源空间均衡与动态调控,创建了一套完整严谨、可动态调控的“四水四定”模型体系。通过模糊信息粒化窗口的支持向量机模型预测区域未来总用水量,利用基于时间序列相似性分析的自回归支持向量机模型预测区域未来分用水量,并对两类数据进行不确定性分析;构建了复杂回归函数对各类用水指标进行情景预测,经统计检验后将其作为当前用水模式下未来用水指标;构建了“四水四定”水资源承载力模型和水资源空间均衡模型,基于未来总用水量、未来各分用水量、未来用水指标,选用水资源负载系数、用水效益和水土资源匹配系数3个指标,结合基尼系数量化水资源空间均衡度,分析当前用水模式下未来水资源均衡度;构建了最优化模型,以最小化基尼系数为目标函数调整未来用水模式,实现水资源动态调控。所创建的模型体系可以实现未来不同时间尺度下的水资源空间均衡与动态调控。

基于水流牵引力的河道岸坡稳定性分析

基于极限平衡理论,结合水平条分法,将Bishop法的竖直条间力关系转换到水平土条上,推导出水流牵引力作用下均质岸坡稳定安全系数的理论计算公式,将其结果与ABAQUS有限元软件的强度折减法模拟的计算结果进行对比分析。结合工程实际,分析水流牵引力对不同坡比河流岸坡的稳定性影响规律。结果表明,理论计算公式与软件模拟的结果基本吻合,误差不超过2.1%。河流中水流牵引力会增大岸坡土体的下滑力矩,降低河流岸坡土体稳定安全系数;当岸坡土体遭受降雨、坡脚土体劣化作用等多因素作用下而处于临界稳定状态时,水流牵引力可能成为滑坡启动的关键因素;在河流岸坡失稳滑动时,水流牵引力将导致滑体向河道方向滑移更远距离,加重滑坡对河流航道安全的危害;坡度越陡,岸坡稳定安全系数受水流牵引力的影响越大。在进行高陡河流岸坡稳定性分析时,水流牵引力是与强降雨、泥石流等因素同样重要且不可忽视的导致岸坡灾变失稳的外部荷载作用。