A Flux Detection Probe to Quantify Dynamic Groundwater-Surface Water Exchange in the Hyporheic Zone

A new probe was designed to quantify groundwater-surface water exchange in the hyporheic zone under dynamic stage condition. Current methods focus on either vertical pore water velocity or Darcy flux measurements. Both parameters must be understood to evaluate residence time and mass flux of constituents. Furthermore, most instruments are not well suited for monitoring instantaneous velocity or flux under dynamic exchange conditions. For this reason, the flux detection probe (FDP) was designed that employs electrogeophysical measurements to estimate in situ sediment porosity, which can be used to convert pore water velocity to Darcy flux. Dynamic pore water velocity is obtained by monitoring fluid conductivity and temperature along the FDP probe. Pressure sensors deployed at the top and bottom of the probe provide the additional information necessary to estimate vertical permeability. This study focuses on the use of a geophysical method to estimate pore water velocity, porosity, and permeability within a controlled soil column where simulated river water displaces simulated groundwater. The difference between probe derived and theoretical pore water velocity using natural tracers such as electrical conductivity and temperature was −4.9 and 3.9% for downward flow and 1.1 and 12.8% for upward flow, respectively. The difference in porosity calculated from mass and volume packed in the soil column and probe measure porosity ranged between −3.2% and 1.5%. Also, the calculated hydraulic conductivity differed from probe derived values by −8.9%.     

Application of a coil‐type TDR probe for measuring the volumetric water content in weathered granitic bedrock

As a first step toward describing water flow processes in bedrock, a coil‐type time domain reflectometry (TDR) probe capable of measuring volumetric water content, θ, in weathered bedrock at three depths was prepared. Because the coil‐type TDR probe is large in diameter (19 mm), it can be installed even in highly weathered bedrock more easily and appropriately than conventional TDR probes that consists of two or three rods of small diameter (5‐8 mm). The probe calibrations suggest that the values measured by the probe are very sensitive to changes in θ. Using the calibrated probe together with commercially available profile soil moisture sensors, the θ profile was monitored for 1 year. Even rainfall events with relatively small cumulative rainfall of 15 mm increased the bedrock θ, and the increments were comparable to those in the soil. After the end of the rainfall events, the bedrock θ displayed a more rapid drop than the soil, and varied little during the period of no rainfall. The water storage showed similar tendencies. These observations suggest that the bedrock θ is controlled by clearly distinguishable macropores and micropores within the bedrock. It is concluded that the coil‐type TDR probe is very effective in determining θ in weathered bedrock, and that bedrock, conventionally defined by conducting cone penetration tests and treated as impermeable, does conduct and hold substantial amounts of water, and therefore contribute greatly to hydrological processes in headwater catchments. Copyright © 2007 John Wiley & Sons, Ltd.     

The effect of artificial modification in the E region on HF ray propagation

During RF heating at 4.04 MHz an increase of 5 dB in the signal strength of a 4.2 MHz probe wave has been observed. This is attributed to a heater induced increase in electron density in the E region leading to the opening up of a low angle propagation path from probe transmitter to receiver. The geometry of the experiment is consistent with an electron density increase distributed in a torus in the E region centred above the heater site.     

投弃式海流电场剖面仪研制

本文分析了投弃式海流电场剖面仪的发展,简介了海流感生电场的基本原理,提出了投弃式海流电场剖面仪的技术方案.根据投弃式海流电场剖面仪的实际需求,研发了XCP海流电场传感器,并通过XCP探头的自旋转(16 r/s),实现了将海流电场信号AM调制并频移至海流电场传感器的超低噪声频段,解决了在高噪声背景下快速测量纳伏级微弱海流电场信号.设计实现了XCP探头前端弱信号处理电路,对海流电场微弱信号进行滤波提取的同时可实现对海流电场同向分量进行硬件电路补偿,在一定程度上克服了XCP探头下沉引起感生电场的强干扰.在XCP探头内部采用SoPC技术实现对海流电场信号、罗盘线圈信号和温度信息的快速测量及其数字化处理,并将数字信息以UART协议及LVDS物理层数传方式发送到XCP浮筒端.开创了长度2 km、直径0.1 mm漆包线动态数据传输技术,解决了XCP探头和XCP浮筒之间的数字化数据传输问题.根据XCP探头所采集的海流电场信号与罗盘线圈信号的同相分量I_n、正交分量Q_n、基线量B_n数据,研究了XCP探测方法,从而计算出了海流的东向与北向相对速度分量V_Er、V_Nr.采用所研发的XCP,在我国南海海域首次采集到海面至海下千米深度的XCP海流电场信息和海洋温度信息.     

Application of 3D Printing to the Manufacturing of Groundwater Velocity Probes

For the purposes of risk mitigation and remediation design, Darcy's Law calculations, that are typically used to estimate flow direction and magnitude, can be usefully supplemented with more direct measurements. The point velocity probe (PVP), which measures groundwater velocity by conducting a mini‐tracer test across a cylindrical probe surface, was developed to address this need. Laboratory and field experiments have shown that these probes can provide accurate velocity magnitude and direction measurements at the centimeter scale. In an effort to streamline the production of PVPs, three‐dimensional (3D) printing was investigated. The 3D printer produces a plastic probe body with designated detector and injection port locations. The subsequent installation of injection lines and detector wires requires, for a single‐port probe, no longer than 1–2 h of assembly time, compared to approximately 10 h to assemble previous designs (mainly determined by injection port installation). Probes can be printed in batches with the number of units made depending on the printer and probe size. Laboratory tests of the original PVP models yielded velocity magnitudes and directions with average errors (from expected values) of ±9% to ±15% and ±8°, respectively. A printed PVP was tested in a nested storage tank system (NeST) packed with sand that mimics flow conditions through a sandy aquifer. The probe was tested at multiple pumping rates with the injector port at angles of (α =) 30°, 45°, and 75° from the expected linear flow direction. The printed PVPs provided an average magnitude percent error of ±13.5% and an average direction error of ±4°. This shows that in laboratory tests, printed PVPs performed as well as the original probes previously reported, making them viable units for field applications as well as being quicker to assemble than the earlier designs.     

基于探空火箭的朗缪尔探针方案设计

为研究中国低纬电离层垂直高度的精细结构,研发了一种以探空火箭为平台朗缪尔探针,用于就位测量电离层空间等离子体的特性参数及其扰动情况.本文分析了朗缪尔探针的任务需求和目标,并在朗缪尔探针基本测量原理的基础上,对朗缪尔探针基本测量方案进行了论证分析和设计,包括传感器形状、大小和表面镀层的选取设计,双探针的设计,扫描电压和工作模式的设计,及电子学测量电路的设计.本朗缪尔探针采用两路完全相同的球形探针,两路探针同步工作,各自独立完成测量.朗缪尔探针研制完成后,分别进行了信号模拟源测试和等离子体源测试:信号模拟源测试结果显示两路探针电子学工作状态良好,对微弱电流信号的响应具有很高的线性度;在等离子体模拟装置内对电子探针整机测试的初步结果表明该载荷可以正确测量等离子体的特性参数,能够满足科学探测的需求.     

中国电磁监测试验卫星朗缪尔探针数据反演方法研究

朗缪尔探针是目前国际上广泛应用的一种空间等离子体环境就位探测技术.中国电磁监测试验卫星上搭载的朗缪尔探针,是我国首次将探针技术应用于星载平台.本文基于电磁监测试验卫星朗缪尔探针的观测原理及Irving Langmuir等提出的近似理论公式,针对朗缪尔探针的仪器特点,提出了等离子环境下朗缪尔探针观测数据的简化反演方法,并依据朗缪尔探针鉴定件的等离子体罐试验数据对该方法进行了比较验证.结果表明,该数据反演方法的效果较好,可以作为电磁监测试验卫星朗缪尔探针观测数据反演的基本方法,并为后续数据处理提供技术基础.      

A Ge(Li) BORE HOLE PROBE FOR IN SITU GAMMA RAY SPECTROMETRY*

This report describes the construction and properties of a Ge(Li) bore hole probe for in situ gamma ray spectrometry. The probe has the form of a cylinder 8.9 cm in diameter and 160 cm long. It contains a 22 cm³ coaxial Ge(Li) detector, cooled by liquid nitrogen. Holding time of the assembled probe is in excess of ten hours, energy resolution is 2.3 keV for 122 keV photons and 2.6 keV for 1333 keV photons. The probe has been used in field experiments in the Ranstad uranium mine and for the study of neutron activation spectra obtained in bore hole models. Results from these experiments are presented and discussed. It is stressed that the Ge(Li) probe gives promise to become a powerful tool in bore hole activation analysis.     

地磁房湿度对地磁观测的影响及解决方案

地磁房湿度变化较快或过大都易引起地磁数据的异常变化,且室内湿度不易控制,地磁房、磁通门磁力仪探头湿度智能在线分析监控系统,可以实时显示监控地磁房、磁通门磁力仪探头湿度的变化,超过湿度阈值则发出报警信号,进而可以采用科学的方法控制探头观测环境的湿度,提高观测数据的稳定性、可靠性。本文介绍了该系统的设计思路和主要功能。     

An electrical resistivity measurement in molten basalt during the 1983 Kilauea Eruption

During the recent 1983 eruption of Kilauea Volcano in Hawaii, a field measurement of electrical resistivity was made in an 1118°C molten lava flow. A probe containing a four electrode. Wenner aray was inserted into the molten basaltic lava flow at a point about 100 m from the erupting vent. The probe indicated an electrical resistivity of approximately 40 ohm-m for the freshly-erupted molten lava. This value is consistent with existing, but sparce, laboratory data for molten rock in this temperature range. This work was performed by Sandia National Laboratories supported by the U.S. Department of Energy under contract number DE-ACO4-76DPO0789.     

A new telluric KCl probe using Filloux's AgAgCl electrode

The measurement of the telluric field's long-time variations requires stable instruments in the period range above 1 day. Obviously, most problems arise from drifting voltages between the telluric probes. Good results have been achieved using a three chamber Hempfling KCl probe together with Filloux's AgAgCl electrode. However, a one chamber probe of 0.6 m length and 0.06 m diameter filled with saturated KCl solution may be sufficient for some applications and additionally allows permanent control of the electrolyte's salt concentration. In a field test the telluric field at a single site was simultaneously observed using one and three chamber probes separated by 25 and 55 m resp. For periods shorter than 1 hour the noise level of the electrodes was found to be less than 1 (mV)²/Hz whereas in the period range between 1 hour and 1 day it increases to 100 (mV)²/Hz. Consequently, surveys investigating long periods of the telluric field can be carried out using small electrode separations of a few tens of meters. Furthermore, the stability of this probe negates the need to interrupt the time series for servicing of the probe. However, the one chamber probe is somewhat inferior to the three chamber probe with regard to temperature dependence at long periods.     

实现数据库管理震源参数的探索

就如何利用数据库，结合Java、XML等手段对震源参数管理进行了一些探索，并给出了一些在一个实际系统中实现了的例子。     

Effect of photoelectric emission on blunt probe conductivity measurements in the stratosphere

Two identical planar blunt probes of stainless steel material, biased with a bipolar ramp voltage, are used to measure the stratospheric polar conductivities to altitudes of 34 km. One probe (DP) is mounted closer to the gondola, looking downwards and shielded from sunlight, while the other (SP) is mounted looking sideways, away from the gondola. The daytime observations of positive ions in the 29–34 km altitude range with SP, and of negative ions at 34 km with DP, show photoelectric contaminations induced by solar UV radiations in the 190–230 nm band. These contaminations are found to be due to photoemissions from the SP probe steel surface and from the carbon paint that coats the surface of the gondola, respectively. It is found that, a segment of the photocurrent contaminated I–V curve, recorded with SP at higher negative probe potentials, is linear, and it can give the ambient positive polar conductivity.     

双探针型海底热流计的结构优化

本文在现有海底热流探针制作技术条件下,首先建立了脉冲式双探针海底测量单元的有限元数值模型,模拟获得多组参数下的温度-时间数据,作为“实测”数据,再用脉冲加热有限长线热源(PFLS)模型求解待测介质热导率及其相对误差上限(RE_λ-UL),并以RE_λ-UL最小为原则,对双探针热流计的结构进行优化.结果表明:(1)在不同探针脉冲强度(q)、温度测量误差(ΔT_m)和探针长度(L)组合下,都存在最佳探针间距(Best_r),使得RE_λ-UL降到最低;(2)随着q增大或ΔT_m减小,Best_r逐渐增大;(3)当q、ΔT_m及探针半径(a)都给定时,Best_r与探针长度(L)呈线性正相关;(4)当a=1.0 mm,且q、ΔT_m分别取为628.0~1100.0 J·m^-1、0.5~1.0 mK,若L在20.0~42.0 mm之间时,则Best_r在18.0~30.0 mm之间,此时介质热导率相对误差上限可控制在5.5%以内,同时测量温度可在6 min内达到最大值,即脉冲加热开始后,温度测量只需约7 min,便可满足介质热导率的求解,这比目前常用的Lister型热流计所需海底测量时间缩短8 min左右.     

Location and Characterization of Subsurface Anomalies Using a Soil Conductivity Probe

An electrical conductivity probe, designed for use with "direct push" technology, has been successfully used to locate buried drums, contaminant plumes, and to precisely locate and characterize a previously installed permeable reactive iron wall. The conductivity probe was designed to characterize various soil and sediment types as it was driven through the dry and saturated soil matrix; however, its ability to locate and characterize subsurface anomalies may also prove to be a valuable asset. The probe uses an electrical field that works like and mimics the results from an oilfield engineering tool called the Wenner array. This electrical field array penetrates into the soil matrix to measure the electrical conductivity of the soil matrix surrounding the probe to a radius of about two to four inches. This tool has allowed operating personnel to verify the location of manmade or natural subsurface anomalies with precision.     

Microcosm Assessment of a DNA Probe Applied to Aerobic Degradation of cis-1,2-Dichloroethene by Polaromonas sp. Strain JS666

A molecular biological tool based on an organism-specific DNA sequence does not necessarily indicate in situ activity but serves important functions of evaluating the potential for biodegradation and mapping the distribution of an organism. Currently, DNA-based probes are accepted as evaluative tools for site assessment. However, these techniques are far from standardized, and information on precision is usually lacking. Here, we present the development and evaluation of a DNA probe for Polaromonas sp. strain JS666, a bacterium that couples growth to aerobic oxidation of cis-1,2-dichloroethene (cDCE), and is therefore a promising candidate for bioaugmentation at sites where cDCE has accumulated in aerobic zones. The DNA probe was used in conjunction with quantitative polymerase chain reaction to track the abundance of JS666 in microcosms. This series of studies has allowed explicit resolution of the accuracy and precision of the probe and its correlation with variations in microcosm performance. We determined that the method is sufficient to monitor distribution of JS666 at bioaugmented sites. We found within environmental, mixed cultures, that the DNA target does not persist long after cell death, demonstrating that positive result from the probe is a strong indicator that degradation can occur in suitable environmental conditions. Finally, in the absence of suspected predation, the probe accurately and precisely tracks growth. Collectively, the studies appear to validate the utility of the molecular probe for site assessment in a bioaugmentation context.     

Measurement of near surface soil water content using a capacitance probe

The portable surface capacitance insertion probe was used to measure the in situ water content of near surface soil layers. The probe readings were calibrated against gravimetric samples collected over a wide range of water contents, and were found to be very closely correlated. The capacitance probe was used repeatedly in time and space at a field site where ridges and furrows ensured a regular pattern of soil water variations. The observed spatial variations of the water content were related to topography and land mangement. The degree of variability was dependent on the average water content.     

Differences Between Water- Level Probes

Water-level probes, even of the same make and model, may not give the same water-level measurement. If more than one probe is used on a site, it may be useful to measure the differences in water-level measurements, and, if necessary, to normalize the water levels to a single reference probe.     

Vadose Zone Monitoring with the Neutron Moisture Probe

The neutron moisture probe is widely applicable to vadose zone monitoring problems which require measuring variable moisture contents. Neutron data are proportional to hydrogen density (modified by local chemistry) and sensitive to wetting fronts as well as changing volumes of hydrocarbon liquids. They cannot, however, be used to confirm contaminant chemistry, nor to detect steady-state flow. Neutron data are amenable to statistical analysis, providing a measure of the significance of data variations. Detection of incipient moisture changes at numerous monitoring locations is more practical using raw neutron data than data calibrated for moisture content because calibrations suffer from uncertainties associated with soil heterogeneities. When properly applied, the neutron probe is an effective monitoring tool as illustrated by three example applications described in this paper: (1) neutron moisture logs are used to detect subtle lithologic changes and identify monitoring horizons; (2) sequential neutron data are used to track induced saturation at a soil flushing pilot study; and (3) neutron logs from a horizontal access tube beneath a waste facility are used to pinpoint moisture anomalies.     

新型质子旋进磁传感器的研制

新型质子旋进磁传感器在传统探头的基础上,根据新的观测环境要求对探头进行了改进,在实现无向性观测的同时,进一步提高了探头线圈的Q值及抗干扰能力,为提高观测系统的信噪比、降低仪器功耗创造了重要的条件。