EPRI has been testing and evaluating a pre-prototype, non-contact, portable sensor that can remotely measure line currents flowing in a polyphase transmission line by means of measuring the external magnetic fields emanating from the line. The geometry of the power line is assumed to be known to an accuracy that can be readily determined from mechanical drawings with the exception that the vertical height of the power lines to ground will be considered to be an unknown. Presently, the system is designed to monitor only the 60 Hz component of line current. However, other harmonics of the fundamental power system and signals propagating on the power system could be readily obtained as well. The constraints on the final sensor system are that it must be field portable, setup time must be short (less than 30 minutes) with minimal setup tool utilization, accuracy should be better than 5, and actual currents flowing through a transmission line cannot be used to calibrate the proposed sensor. To quantitatively evaluate the feasibility of the concept, the sensor was placed under a 230 kV transmission line that was instrumented at the nearby substation to measure 60 Hz current flowing through each phase. Our paper will describe in detail the sensor, the test setup, and the final results.

关键词：传感器；探测器；电流；便携式设备

查看摘要 索取原文[8页]

Heaving has been observed in sulfate soils when they are treated with lime or cement additives. This heaving is attributed to the formation of an expansive mineral known as Ettringite. Ettringite is known to form from reactions of calcium ions from the chemical additives, sulfates in soils and free reactive alumina released from treated clayey soils and stabilizers. Since chemically-treated bases have been used to support the pavement infrastructure, this type of heave has distressed the pavements and as a result, it became necessary to develop alternate stabilization techniques to treat sulfate soils. Evaluation of the sulfate heaving requires long laboratory-based mix designs, since it is important to perform the long term swell tests on treated soils. Hence, it is important to develop a faster and reliable device and test method to assess and evaluate sulfate heaving in chemically-treated sulfate soils in a short time frame. The intent of the present research was to devlop an innovative hybrid sensor, BM sensor comprised of Bender Element (BE) and moisture based Time Domain Reflectometry (TDR) technologies to assess the sulfate heave in treated soils in a quick time frame. This hybrid sensor was successfully used in the laboratory for quick assessments of soil stiffness and moisture content variations in cement and lime-treated sulfate soils. After succesful and quick assessments of the heaving, the sensor was used in the field test section to monitore stiffness and moisture content changes. Both laboratory and field studies showed that this sensor can be used in the field to assess sulfate heaving. More field studies will further enhance and promote the use of this sensor for quick evaluation of sulfate heaving.

关键词：传感器；混合动力系统；土壤稳定；硫酸盐

查看摘要 索取原文[72页]

The Sensor Research Lab at the Naval Postgraduate School is developing a real-time THz imaging camera. Vital to its design is the metamaterial absorbing layer (metafilm) within each pixel that allows for THz absorption. While there are numerous applications in the THz region, sensors and sources for THz energy have much room for improvement. The use of metamaterial technology for the purpose of a THz sensor has the potential to reduce costs while greatly improving sensitivity performance. The Sensor Research Lab has fabricated metafilms capable of near 100 percent absorption. In this research project, absorption characteristics of a set of metamaterials were measured using Fourier transform THz spectroscopy and modeled using an RLC circuit. The model provides a good description of the absorption characteristics and should assist in better understanding of the electromagnetic interactions within the metafilm.

关键词：传感器；超材料；电磁辐射；共振吸收

查看摘要 索取原文[77页]

This report summarizes technical progress on the program Multiplexed Optical Fiber Sensors for Coal Fired Advanced Fossil Energy Systems funded by the National Energy Technology Laboratory of the U.S. Department of Energy, and performed jointly by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering and the Department of Materials Science and Engineering at Virginia Tech. This three-year project started on October 1, 2008. In the project, a fiber optical sensing system based on intrinsic Fabry-Perot Interferometer (IFPI) was developed for strain and temperature measurements for Ultra Supercritical boiler condition assessment. Investigations were focused on sensor design, fabrication, attachment techniques and novel materials for high temperature and strain measurements.

关键词：传感器；光学探测器；探测器；珀罗干涉仪

查看摘要 索取原文[134页]

Several advances are made toward a microelectromechanical (MEMS) acoustic direction-finding sensor based on the Ormia ochracea fly's ear. First, linear elastic stiffness models are presented and then validated by using a nanoindenter to measure the sensor s stiffness directly. The measured stiffness is highly linear, and the resonant frequencies are correctly predicted by the models presented. Additional nanoindenter results suggest that the sensor can be exposed to at least 162 decibel sound pressure level with no loss of function. Next, an improved capacitive readout system using branched comb fingers is presented. This design is shown to double electrical sensitivity to motion. Finally, it is shown that residual stress-induced curvature in the sensors greatly reduces their sensitivity by effectively shrinking the readout capacitors. A simple model of this curvature is presented and then verified by measurements. This model offers an extremely straightforward means of predicting curvature in similarly fabricated structures. It is also shown that perforations in the sensor s structure have no effect on curvature. The results presented here provide several essential tools for the continued development of the MEMS acoustic direction-finding sensor.

关键词：传感器；声波探测仪；测向；微机电系统

查看摘要 索取原文[109页]

A miniature sensor probe, composed of four sensors which monitor the partial pressure of O2, CO2, H2O, and temperature, designed to operate in the portable life support system (PLSS), has been demonstrated. The probe provides an important advantage over existing technology in that it is able to operate reliably while wet. These luminescence-based fiber optic sensors consist of an indicator chemistry immobilized in a polymeric film, whose emission lifetime undergoes a strong change upon a reversible interaction with the target gas. Each sensor includes chemistry specifically sensitive to one target parameter. All four sensors are based on indicator chemistries that include luminescent dyes from the same chemical family, and therefore exhibit similar photochemical properties, which allow
performing measurements of all the sensors by a single, compact, low-power optoelectronic unit remotely connected to the sensors by an electromagnetic interference-proof optical fiber cable. For space systems, using these miniature sensor elements with remote optoelectronics provides unmatched design flexibility for measurements in highly constrained volume systems such as the PLSS. A 10 mm diameter and 15 mm length prototype multiparameter probe was designed, fabricated, tested, and demonstrated over a wide operational range of gas concentration, humidity, and temperature relevant to operation in the PLSS. The sensors were evaluated for measurement range, precision, accuracy, and response time in temperatures ranging from 50?F-150?F and relative humidity from dry to 100% RH. Operation of the sensors in water condensation conditions was demonstrated wherein the sensors not only tolerated liquid water but actually operated while wet.

关键词：传感器；便携式生命保障系统；小型化；光化学反应

查看摘要 索取原文[10页]

The long-term goals of this project are to create a new capability for under-ice acoustic navigation and communication, specifically in support of the ONR Marginal Ice Zone (MIZ) Departmental Research Initiative (DRI). The MIZ DRI field program will occur in 2014, with trials starting in 2013. The MIZ DRI will include a large array of sensors deployed on the surface of the ice, as well as Sea Gliders and drifters operating below. The project seeks to answer a number of important science questions, and will investigate surface forcing, both mechanical and solar, on the ice and the upper water column. The response of the upper ocean will be established using data collected sub-sea by the autonomous vehicles operating under the ice, and then assimilated into oceanographic models.

关键词：传感器；声学导航；声探测；传感器阵列

查看摘要 索取原文[6页]

A transformative calibration methodology is presented for predicting transient surface temperatures in a thermally conducting medium from in-depth, time-varying temperature measurements. The surface temperature is resolved using two experimental runs and a newly devised first-kind Volterra integral equation. The first experimental run involves calibration with known surface temperature while the second run involves resolving the surface temperature of interest through the ill-posed integral equation. This paper presents the concept genesis and numerically demonstrates the concept for feasibility, robustness, stability and accuracy. From this demonstration, we propose to implement surface placed thermographic phosphors in the calibration stage of the inverse method for estimating the required surface temperature. As a preliminary study, we consider transient, constant property, onedimensional heat conduction in a semi-infinite medium. It is mathematically demonstrated that a Volterra integral equation of the first kind is developed for estimating the surface temperature using a calibrated system (host material and sensor). Sensor characterization, explicit sensor positioning and thermophysical properties are implicitly contained in the new calibration integral equation. The calibration integral equation displays only four terms; namely, the measured front surface temperature and corresponding measured in-depth temperature response associated with the calibration run; and, the unknown surface temperature and its measured in-depth temperature response associated with the second run. Preliminary numerical results indicate the merit of the concept.

关键词：传感器；热流量；测量仪器；温度测量

查看摘要 索取原文[32页]

We have made high resolution x-ray microcalorimeters using superconducting MoAu bilayers and Nb meander coils. The temperature sensor is a Magnetic Penetration Thermometer (MPT). Operation is similar to metallic magnetic calorimeters, but instead of the magnetic susceptibility of a paramagnetic alloy, we use the diamagnetic response of the superconducting MoAu to sense temperature changes in an x-ray absorber. Flux-temperature responsivtty can be large for small sensor heat capacity, with enough dynamic range for applications. We find models of observed flux-temperature curves require several effects to explain flux penetration or expulsion in the microscopic devices. The superconductor is non-local, with large coherence length and weak pinning of flux. At lowest temperatures, behavior is dominated by screening currents that vary as a result of the temperature dependence of the magnetic penetration depth, modified by the effect of the nonuniformity of the applied field occurring on a scale comparable to the coherence length. In the temperature regime where responslvity is greatest, spadal variations in the order parameter become important: both local variations as flux enters/leaves the film and an intermediate state is formed, and globally as changing stability of the electrical circuit creates a Meissner transition and flux is expelled/penetrates to minimize free energy

关键词：传感器；磁导率；超导体（材料）；量热仪

查看摘要 索取原文[5页]

There is a great need to develop non-GPS based methods for positioning and navigation in situations where GPS is not available. This research focuses on the development of an Ultra-Wideband Orthogonal Frequency Division Multiplexed (UWB-OFDM) radar as a navigation sensor in GPS-denied environments. A side-looking vehicle-fixed UWB-OFDM radar is mounted to a ground or aerial vehicle continously collecting data. A set of signal processing algorithms and methods are developed which use the raw radar data to aide in calculating the vehicle position and velocity via a simultaneous localization and mapping (SLAM) approach. The radar processing algorithms detect strong, persistent, and stationary reflectors embedded in the environment and extract range/Doppler measurements to them. If the radar is the only sensor available, the measurements are used to directly compute the vehicle position. If an existing navigation platform is available, the measurements are combined with the other sensors in an EKF. The developed algorithms are tested via both a series of airborne simulations and a ground- based experiment. The computed navigation solution performance is analyzed with the following sensor availability: radar-only, INS-only, and combined radar/INS. In both simulations and experimental scenarios, the integrated INS/UWB-OFDM system shows significant improvements over an INS-only navigation solution.

关键词：传感器；雷达导航；多普勒系统；全球定位系统

查看摘要 索取原文[132页]