HDR Experiments at Falkenberg/Bavaria

A test site for HDR experiments has been set up in granite in the Bohemian massif in east Bavaria. A large fracture was stimulated by hydraulic fracturing in a depth of 250 m. The orientation of the fracture was investigated by seismo-acoustic recording during the frac-experiments and by examining the fracture pattern initiated in the injection interval of the borehole by an impression packer and by acoustic televiewer measurements. Geoelectric measurements for fracture location at the surface were also tested before attempting to drill through the fracture. The fracture has now been intersected by 6 additional boreholes at distances between 2 m and 70 m from the initiation interval.According to the results of seismo-acoustic recording, temperature logging and acoustic televiewer measurements in the intersection boreholes, a single plane artificial fracture has been produced, striking E-W and dipping 50°S. The orientation of the fracture, which should be normal to the least compressive principal stress, and the value of the normal stress on the fracture are not consistent with the direction and the values of the principal stresses determined by wire line hydraulic fracturing stress measurements.Various hydraulic experiments were performed in the different boreholes to investigate the mechanical reaction of the fracture due to varying fluid pressure, the hydraulic properties of the fracture, the fluid losses and the heat exchange within the fracture. The models developed to interpret the results make it possible to translate the results to greater depth and higher flow rates.     

High resolution solid-state 13C CPMAS study of neutral and partially oxidized aluminium polyfluorophthalocyanines

This paper reports a high resolution solid-state ¹³C CPMAS study of the low dimensional phthalocyanine (Pc = C₃₂H₁₆N₈) conductors (PcAlF)-(MoF₆)_0.38, (PcAlF)(IF₅)_0.43 and (PcAlF)(XeF₂)_0.35 as well as the precursor (PcAlF)_n. This study confirms that the stacking configuration of Pc rings along polymeric chains of neutral polymer is eclipsed. The four inequivalent carbon sites resulting from this structure are clearly separate and identified. From this study it is concluded that intrachain disorder is more extended in MoF₆- and IF₅-doped compounds than in the XeF₂-doped one.     

近50年淮河流域旱涝与太阳黑子的关系研究

根据淮河流域1961～2010年的月降水资料,用Z指数法分析了淮河流域旱涝灾害规律,并采用频率分析法分析了太阳黑子极值年附近的旱涝特征、Morlet小波分析淮河流域的旱涝指数和太阳黑子数时间序列之间的周期性和相关性。结果表明,Z指数能较好地反映淮河流域旱涝灾害的实际情况,且洪涝化程度随淮河流域旱涝事件频率增加而加大;淮河流域旱涝灾害与太阳活动有一定的对应关系,淮河水系地区分别在太阳黑子m、M年附近易发生涝灾、旱灾,旱涝指数约存在4、10、16年的主要周期;沂沭泗水系地区在太阳黑子M年附近易出现旱灾,旱涝指数约存在3、12、30年的主要周期,但局部时间段上有较明显的相关性,随时间段的不同,相关变化也不同。     

二次自蔓延高温合成钙钛矿固化90Sr

采用二次自蔓延高温合成(SHS)技术制备钙钛矿固化高放废物90Sr,通过XRD, SEM和PCT粉末浸泡法,研究了钙钛矿固化体的微观组织、浸出率以及其对高放废物~(90)Sr的最大包容量.结果表明,固化体样品密度高、孔隙率小,浸出率都小于0.1 g/(m~2·d),对SrO的包容量可达36%(质量分数);表明自蔓延高温合成的钙钛矿人造岩石固化体化学稳定性好、包容量大,是固化高放废物的理想固化体.     

5×5棒束通道中简单支撑格架对流动过冷沸腾传热的影响分析

采用壁面热分配模型(即RPI模型)对PSBT基准题中的5×5均匀加热全长棒束过冷沸腾传热进行了数值模拟研究。重点分析了加热段末端搅混格架（MVG）下游简单支撑格架（SSG）对棒束通道内流动过冷沸腾传热特性的影响。在水力特性方面,研究发现SSG的形阻压降约为MVG的53%,且对棒束通道内的横向流动具有显著抑制作用。为反映SSG对搅混过程的影响,采用子通道平均横流速度比沿轴向的发展过程对其进行了分析。分析发现,在SSG附近横流速度比迅速衰减,衰减后的横流速度比与光棒束时的大小相当。由于SSG对横流过程的破坏,改变了发热表面的传热特性,在其下游气相迅速包覆加热表面,蒸发热流密度较无SSG情况偏高5%,加热段末端空泡份额偏高0.006,壁面过热度偏高0.3 ℃。     

水资源集约安全利用评估模型构建及应用

为贯彻落实"十六字"治水思路的必然要求和重要任务之一——水资源集约安全利用的评价工作,在节水优先和生态优先方针指导下,探讨了水资源集约安全利用的评价指标体系,进而采用AHP-CRITIC综合赋权,引入对称交互熵多属性排序法,建立了水资源集约安全利用评估模型.应用于2019年中国31个省级行政区(不含港澳台)的研究结果表...     

Additive scale control optimization and operation modes

Along the Gulf Coast there are three Saudi main desalination sites. These are, South to North, Al-Khobar, Al-Jubail and Al-Khafji. In these plants some 300 MIGD of distillate could be produced when all 58 MSF evaporators are run at a low top brine temperature (TBT) of 90°C. An additional 50 MIGD could be produced when the 52 evaporators designed as well, for high TBT of 113°C or more are run near this temperature. All these 58 evaporators are designed with additive scale control. Therefore additive treatment and cost are vital to East Coast Saudi Arabian plants.This paper will review original design operating parameters and performance. It will also report on some revisions reviewed or developed and executed at these plants. The changes were developed and adopted in an attempt to optimize production cost particularly scale control additive dose levels at different top temperatures. These plants were designed and undergone performance and trial runs at additive dose levels of 12 to 3 ppm. These were then reduced after the warranty periods to extremely low values of 2.2 to 0.8 ppm at different top temperatures.     

Transient burn-out in liquid helium with rapid rise of heat flux

This Paper presents the results of experimental and theoretical investigations of transient burn-out in liquid helium moving freely. Heat input in the open vertical channel with liquid helium was increased linearly. The rate of increase of heat flux was varied from 100 to 23 000 W m⁻² s⁻¹, ensuring both quasi-steady and transient conditions. When heat input rose rapidly, burn-out simultaneously appeared over the entire channel length. This can be explained by the peculiarities of unsteady hydrodynamics. A physical model of transient boiling burn-out in a pool and in channels is presented. Relationships for some forms of heat flux variation in time have been derived on the basis of this model. Present experimental data and results of other authors are verified by means of the developed model.     

Electrical resistivity of pitch during heat treatment

The d.c. electrical resistivity of coal-tar pitch has been measured from ambient temperature to 450 °C. The change in resistivity with temperature up to 200 °C has been found to be consistent with viscosity-controlled diffusion of current carriers. In an isothermal study at 450 °C, the start of mesophase formation was found to be accompanied by a rapid rise in the pitch resistivity, which subsequently levelled off and remained nearly constant until the onset of mesophase coalescence and phase inversion. The resistivity of the resultant mesophase pitch was found to be less temperature susceptible than that of the parent pitch.     

Relationship between chemical structure and secondary quinoline insoluble formation in electrode binder pitches

The relationship between the rate of secondary quinoline insoluble (QI) formation in coal-tar pitches and variations in their chemical composition is examined. Production of significant concentrations of secondary QI is shown to be accompanied by mesophase formation, the significance of which is discussed in terms of electrode binder performance.