Monitoring artificially stimulated fluid movement in the Cretaceous Dakota aquifer,western Kansas

Aquifer properties can be evaluated by monitoring artificially stimulated fluid movements between wells, if the fluid is heated. Changes in the temperature profile recorded in observation wells indicate the flow path of the heated fluid, which in effect acts as a tracer. A fluid-flow experiment in the Cretaceous Dakota Formation at the Hodgeman County site, west-central Kansas, demonstrated the advantage of using the distributed optical-fiber temperature sensing method for monitoring transient temperature conditions in this hydrological application. The fluid flow in the aquifer was increased by producing water from a pumping well and injecting heated water in an injection well 13 m (43 ft) distant from the pumping well. The time-temperature series data obtained and compared with results from previous pumping tests point to interwell heterogeneity of the aquifer and to a zone in the sandstone aquifer of high hydraulic conductivity. However, the experiment would have allowed further clarification of aquifer heterogeneity and thermal properties if at least one observation well had been present between the injection and production wells. Electronic Publication     

Field technique of permeability tests in highly fissured limestone strata

A design of a dewatering system is necessary for site improvement prior to the construction of some structures. The design of an efficient dewatering system requires estimating the value of the in-situ coefficient of permeability. The available relationships for estimating the permeability coefficient were developed based on limited field measurements and conditions, and their predictions vary by several orders of magnitudes. Therefore, it was necessary to conduct field measurements of permeability and determine the relationship that best fits these measurements prior to the design of a dewatering system for specific geological and site conditions. This paper presents field measurements of permeability in complex chaotic and diagenetic limestone strata. It also offers comparative analysis of several relationships available in the literature for predicting the in-situ coefficient of permeability. The analysis is conducted for both steady and nonsteady conditions. The results show that the coefficient of permeability value is dependent on the water table level, which is affected by the tidal condition. The US Navy equation is shown to give the best correlation with field measurements. Electronic Publication     

粤闽赣交界地区地震活动若干特征及其地震大形势分析

运用地震地质、地震活动是过分分布、地震能量及其量值空间扫描、地震条带、小震频闪数理统计、地震迁移等方法，研究了粤闽赣交界地区地震活动特征，并作了地震趋势分析，认为研究区第四活动幕已临结束，近十年内发生6级以上地震可能性很小，发生5级以上地震概率也不大。     

Geometric adjustment of pools to changes in slope and discharge: a flume experiment

To characterize the factors controlling pool shape, 30 different forced pools were created utilizing a 50% triangular constriction in a 0.5-m wide, 6-m long recirculating flume. Pools were scoured from an initial plane bed of sand with a d₅₀ of 0.25 mm. Pool depth and length were measured and used as dependent variables in least-squares, multiple-regression analyses. Discharge, channel-bed gradient and energy slope were the independent variables. Additional linear-regression analyses were conducted with either pool depth or length and stream power. Results indicate that both pool depth and length are primarily a function of discharge. Channel-bed and energy slopes are also significantly related to pool length but are not significantly related to pool depth. Stream power is significantly related to both pool depth and length, but R² values for pool depth versus discharge indicate stronger relations than those between pool depth and stream power. Observations on the type of geometric adjustment indicate that pools may minimize their rate of energy expenditure primarily through elongation. In contrast, pool depth appears to be more sensitive to the characteristics of the constrictions that create the forced pools. The results suggest that many field studies may suffer from cross-correlation problems. In particular, channel erodibility may exert a more dominant influence on pool geometry than hydraulic controls in many constriction-influenced channels.     

设有液压质量控制系统(HMS)的底层柔性结构动力特性及其地震反应的振型分解法

本文对设有液压质量控制系统(HMS)的底层柔性结构体系的动力特性进行了试验研究和分析,通过对试验结果的分析,证明了设有液压质量控制系统(HMS)的底层柔性结构控制体系近似存在经典振型,其阻尼阵满足正交性条件,所以,可用振型分解法计算受控结构的地震反应。     

On The Small-Scale Dynamics Of Flow Splitting In The Rhine Valley During A Shallow Foehn Event

Flow splitting in the Rhine valley has been observed with a transportable wind lidar (TWL) during a shallow-foehn event in the framework of the Mesoscale Alpine Programme (MAP). The Doppler lidar recorded in detail flow splitting, foehn wind gusts, and flow reversal. Such structures have not previously been observed with comparable detail by conventional in-situinstruments. In addition to the TWL, boundary-layer processes have been documented by means of rawinsondes and surface stations. This paper presents an analysis of the processes giving birth to flow splitting between the Seez and Rhine valleys during Intensive Observation Period (IOP) 5 (1–3 October 1999) by combining the collected data with hydraulic theory. The study shows thatthe splitting of the channelled flow is associated with (1) the existence of a stagnation point at the intersection of the Seez and Rhine valleys, and (2) the deflection of the flow by the lateral sidewalls of the valleys.     

华东飑线过程中的地面中尺度物理特征

本文利用华东中尺度天气试验资料和雷达回波,分析了9例强飑线过程中逐时地面物理量场的变化。提出中尺度散度场的配置及变化与中尺度强对流天气有十分密切的关系,而中尺度扰动辐合强度演变与锋前暖区内的中尺度扰动风场汇合线有关,这些关系往往能预示中尺度强对流天气的出现和发展。有时,在飑线发展的过程中具有中尺度重力波特征。     

闪电河断裂带两侧地质构造特征及铀成矿远景的几点新认识

通过系统的野外和室内工作编制了1:10万闪电河断陷带两侧地质构造及铀成矿远景预测图,在此基础上本文着重阐述了区域成矿背景,并提出几点新的认识。在详细研究了闪电河断陷带两侧地质构造特征后进行了成矿远景区的遴选,并指出本区进一步找矿方向。     

冀东上营地区长河沿岸角闪斜长片麻岩与紫苏花岗闪长岩的关系及其成因

冀东太古宙克拉通线性岩浆-构造混杂岩区内分布有一种具英云闪长岩-花岗闪长岩成分的角闪斜长片麻岩,空间上与紫苏花岗闪长岩密切伴生。角闪斜长片麻岩是紫苏花岗闪长岩受构造变形影响,沿一组共轭构造(N45°E,E15°S)发生退化变质的产物。退变质作用在有水参与的等化学体系内完成,并受最强期变形事件控制。     

Variability of bedload transport and channel morphology in a braided river hydraulic model

This paper investigates variability in bedload transport and channel morphology for 11 replicate experimental runs in an approximately 1:50 braided river model. The experiments, each of 90 h duration, were carried out in a 20 × 3m tilting flume. All the experiments started with the same initial conditions. Bedload transport was measured at 5 min intervals in a collection drum at the exit from the flume. The model showed reasonable hydraulic similarity when compared to prototype rivers. Results show that mean bedload transport rates for the 11 runs vary in the range 0·98 to 1·49gs^?1 (mean + 1·21, coefficient of variation 11 per cent). Within-run transport rates commonly vary from close to zero, to two and occasionally three or four times the mean rate. Within the bedload series, several irregular phases of transport intensity can be observed, but time series analysis of the data show little underlying serial structure (an AR(2) autoregressive model is appropriate). Channel patterns are narrow/braided, are established quickly and remain relatively stable throughout the runs, although channel widths increase between 20 and 103 per cent over the 11 runs. Channel behaviour varies from aggradational to transitional between aggradation and degradation. Time-averaged bedload transport rate is weakly correlated with braiding intensity. In general, these results demonstrate that for a given set of controlling variables, bedload transport and channel morphology can be approximately replicated.