Science.gov

Sample records for advanced moisture sensor

  1. Advanced moisture sensor research and development

    SciTech Connect

    De Los Santos, A.

    1992-10-31

    During this period, testing of the system continued at the American Fructose (AF) plant in Dimmitt, Texas. Testing at the first two sites (dryer output and dryer input) was completed. Following the testing at the second site, the sensor was returned to the Southwest Research Institute (SwRI) laboratories for modifications and for fitting of the additional components required to allow sampling of the material to be measured at the third site. These modifications were completed during this reporting period, and the system is scheduled to be installed at the third site (Rotary Vacuum Filter output) early in the next period. Laboratory measurements of corn germ (to be measured at the fourth site) and a variety of fruits and vegetables (one of which will be measured at the fifth site) have also continued during this period.

  2. Fiber optic moisture sensor

    DOEpatents

    Kirkham, R.R.

    1984-08-03

    A method and apparatus for sensing moisture changes by utilizing optical fiber technology. One embodiment uses a reflective target at the end of an optical fiber. The reflectance of the target varies with its moisture content and can be detected by a remote unit at the opposite end of the fiber. A second embodiment utilizes changes in light loss along the fiber length. This can be attributed to changes in reflectance of cladding material as a function of its moisture content. It can also be affected by holes or inserts interposed in the cladding material and/or fiber. Changing light levels can also be coupled from one fiber to another in an assembly of fibers as a function of varying moisture content in their overlapping lengths of cladding material.

  3. Advanced moisture sensor research and development. Quarterly progress report, August 1, 1992--October 31, 1992

    SciTech Connect

    De Los Santos, A.

    1992-10-31

    During this period, testing of the system continued at the American Fructose (AF) plant in Dimmitt, Texas. Testing at the first two sites (dryer output and dryer input) was completed. Following the testing at the second site, the sensor was returned to the Southwest Research Institute (SwRI) laboratories for modifications and for fitting of the additional components required to allow sampling of the material to be measured at the third site. These modifications were completed during this reporting period, and the system is scheduled to be installed at the third site (Rotary Vacuum Filter output) early in the next period. Laboratory measurements of corn germ (to be measured at the fourth site) and a variety of fruits and vegetables (one of which will be measured at the fifth site) have also continued during this period.

  4. Bulk Moisture and Salinity Sensor

    NASA Technical Reports Server (NTRS)

    Nurge, Mark; Monje, Oscar; Prenger, Jessica; Catechis, John

    2013-01-01

    Measurement and feedback control of nutrient solutions in plant root zones is critical to the development of healthy plants in both terrestrial and reduced-gravity environments. In addition to the water content, the amount of fertilizer in the nutrient solution is important to plant health. This typically requires a separate set of sensors to accomplish. A combination bulk moisture and salinity sensor has been designed, built, and tested with different nutrient solutions in several substrates. The substrates include glass beads, a clay-like substrate, and a nutrient-enriched substrate with the presence of plant roots. By measuring two key parameters, the sensor is able to monitor both the volumetric water content and salinity of the nutrient solution in bulk media. Many commercially available moisture sensors are point sensors, making localized measurements over a small volume at the point of insertion. Consequently, they are more prone to suffer from interferences with air bubbles, contact area of media, and root growth. This makes it difficult to get an accurate representation of true moisture content and distribution in the bulk media. Additionally, a network of point sensors is required, increasing the cabling, data acquisition, and calibration requirements. measure the dielectric properties of a material in the annular space of the vessel. Because the pore water in the media often has high salinity, a method to measure the media moisture content and salinity simultaneously was devised. Characterization of the frequency response for capacitance and conductance across the electrodes was completed for 2-mm glass bead media, 1- to 2-mm Turface (a clay like media), and 1- to 2-mm fertilized Turface with the presence of root mass. These measurements were then used to find empirical relationships among capacitance (C), the dissipation factor (D), the volumetric water content, and the pore water salinity.

  5. Soil-moisture sensors and irrigation management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This agricultural irrigation seminar will cover the major classes of soil-moisture sensors; their advantages and disadvantages; installing and reading soil-moisture sensors; and using their data for irrigation management. The soil water sensor classes include the resistance sensors (gypsum blocks, g...

  6. Porous Si structure as moisture sensor

    SciTech Connect

    Peterson, D.W.; Nguyen, L.T.

    1996-12-31

    Development and characterization of a capacitive moisture sensor made from porous Si is presented. The sensor development was in support of the DoD funded Plastic Package Availability program and was intended for the detection of pinholes and defects in moisture barrier coatings applied to ICs during fabrication or during the plastic encapsulation assembly process.

  7. Inexpensive Microwave Moisture Sensor for Granular Materials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A prototype microwave moisture sensor is described that was assembled from relatively inexpensive microwave components and tested for sensing moisture content in corn and wheat. Components include off-the-shelf voltage-controlled oscillator, isolator, power splitter, two 19-dBi microstrip patch ant...

  8. Evaluation of soil moisture sensors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study evaluated the measurement accuracy and repeatability of the EC-5 and 5TM soil volumetric water content (SVWC) sensors, MPS-2 and 200SS soil water potential (SWP) sensors, and 200TS soil temperature sensor. Six 183cm x 183cm x 71cm wooden compartments were built inside a greenhouse, and e...

  9. Capacitive Soil Moisture Sensor for Plant Watering

    NASA Astrophysics Data System (ADS)

    Maier, Thomas; Kamm, Lukas

    2016-04-01

    How can you realize a water saving and demand-driven plant watering device? To achieve this you need a sensor, which precisely detects the soil moisture. Designing such a sensor is the topic of this poster. We approached this subject with comparing several physical properties of water, e.g. the conductivity, permittivity, heat capacity and the soil water potential, which are suitable to detect the soil moisture via an electronic device. For our project we have developed a sensor device, which measures the soil moisture and provides the measured values for a plant watering system via a wireless bluetooth 4.0 network. Different sensor setups have been analyzed and the final sensor is the result of many iterative steps of improvement. In the end we tested the precision of our sensor and compared the results with theoretical values. The sensor is currently being used in the Botanical Garden of the Friedrich-Alexander-University in a long-term test. This will show how good the usability in the real field is. On the basis of these findings a marketable sensor will soon be available. Furthermore a more specific type of this sensor has been designed for the EU:CROPIS Space Project, where tomato plants will grow at different gravitational forces. Due to a very small (15mm x 85mm x 1.5mm) and light (5 gramm) realisation, our sensor has been selected for the space program. Now the scientists can monitor the water content of the substrate of the tomato plants in outer space and water the plants on demand.

  10. Advanced Sensor Concepts

    NASA Technical Reports Server (NTRS)

    Alhorn, D. C.; Howard, D. E.; Smith, D. A.

    2005-01-01

    The Advanced Sensor Concepts project was conducted under the Center Director's Discretionary Fund at the Marshall Space Flight Center. Its objective was to advance the technology originally developed for the Glovebox Integrated Microgravity Isolation Technology project. The objective of this effort was to develop and test several new motion sensors. To date, the investigators have invented seven new technologies during this endeavor and have conceived several others. The innovative basic sensor technology is an absolute position sensor. It employs only two active components, and it is simple, inexpensive, reliable, repeatable, lightweight, and relatively unobtrusive. Two sensors can be utilized in the same physical space to achieve redundancy. The sensor has micrometer positional accuracy and can be configured as a two- or three-dimensional sensor. The sensor technology has the potential to pioneer a new class of linear and rotary sensors. This sensor is the enabling technology for autonomous assembly of modular structures in space and on extraterrestrial locations.

  11. Development of solid state moisture sensors for semiconductor fabrication applications

    NASA Astrophysics Data System (ADS)

    Pfeifer, K. B.; Kelly, M. J.; Guilinger, T. R.; Peterson, D. W.; Sweet, J. N.; Tuck, M. R.

    We describe the design and fabrication of two types of solid state moisture sensors, and discuss the results of an evaluation of the sensors for the detection of trace levels of moisture in semiconductor process gases. The first sensor is based on surface acoustic wave (SAW) technology. A moisture sensitive layer is deposited onto a SAW device, and the amount of moisture adsorbed on the layer produces a proportional shift in the operating frequency of the device. Sensors based on this concept have excellent detection limits for moisture in inert gas (100 ppb) and corrosive gas (150 ppb in HCl). The second sensor is a simple capacitor structure that uses porous silicon as a moisture-sensitive dielectric material. The detection limits of these sensors for moisture in inert gas are about 700 ppb prior to HCl exposure, and about 7 ppm following HCl exposure.

  12. Moisture infrared sensor for medical applications

    NASA Astrophysics Data System (ADS)

    Monacelli, Eric; Alayli, Yasser; Lofaso, Frederic

    2003-04-01

    The importance of delivering warm, humidified air to patients ventilated through an endotracheal or tracheostomy tube is widely accepted. The use of modern artificial noses or heat and moisture exchangers made of recently developed material could be a solution to both problems of humidification and heat preservation. For this investigation, an IR optical sensor to measure weak partial pressure of water vapor has been designed and realized. This sensor is based on direct molecular absorption in the near IR corresponding to fundamental mode v1 and it is an extrinsic and amplitude modulation type. In the quasi-linear region between 0 to 30 mbars, the calibration curve that represents the transmited power versus the water vapor partial pressure in air shows a high sensitivity with a minimum detectable of 100 μbars. The experimental setup, test procedure, theory analysis, and data processing of the optical water vapor sensor will be described in this article. The sensor has been designed to monitor water vapor in the modern artificial noses.

  13. Advanced sensors technology survey

    NASA Technical Reports Server (NTRS)

    Cooper, Tommy G.; Costello, David J.; Davis, Jerry G.; Horst, Richard L.; Lessard, Charles S.; Peel, H. Herbert; Tolliver, Robert

    1992-01-01

    This project assesses the state-of-the-art in advanced or 'smart' sensors technology for NASA Life Sciences research applications with an emphasis on those sensors with potential applications on the space station freedom (SSF). The objectives are: (1) to conduct literature reviews on relevant advanced sensor technology; (2) to interview various scientists and engineers in industry, academia, and government who are knowledgeable on this topic; (3) to provide viewpoints and opinions regarding the potential applications of this technology on the SSF; and (4) to provide summary charts of relevant technologies and centers where these technologies are being developed.

  14. Microwave moisture sensor for rapid and nondestructive grading of peanuts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A low-cost microwave moisture sensor operating at a single frequency for instantaneous and nondestructive determination of moisture content in peanut kernels from microwave dielectric measurements on peanut pods was developed and tested. The sensor operates at a frequency of 5.8 GHz and uses the pr...

  15. Fiber optic moisture sensor with moisture-absorbing reflective target

    DOEpatents

    Kirkham, Randy R.

    1987-01-01

    A method and apparatus for sensing moisture changes by utilizing optical fiber technology. One embodiment uses a reflective target at the end of an optical fiber. The reflectance of the target varies with its moisture content and can be detected by a remote unit at the opposite end of the fiber. A second embodiment utilizes changes in light loss along the fiber length. This can be attributed to changes in reflectance of cladding material as a function of its moisture content. It can also be affected by holes or inserts interposed in the cladding material and/or fiber. Changing light levels can also be coupled from one fiber to another in an assembly of fibers as a function of varying moisture content in their overlapping lengths of cladding material.

  16. Soil Moisture derivation from the multi-frequency sensor AMSR-2

    NASA Astrophysics Data System (ADS)

    Parinussa, Robert; de Nijs, Anne; de Jeu, Richard; Holmes, Thomas; Dorigo, Wouter; Wanders, Niko; Schellekens, Jaap

    2015-04-01

    We present a method to derive soil moisture from the multi-frequency sensor Advanced Microwave Scanning Radiometer 2 (AMSR-2). Its predecessor, the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E), has already provided Earth scientists with a consistent and continuous global soil moisture dataset. However, the AMSR-2 sensor has one big advantage in relation to the AMSR-E sensor; is has an additional channel in the C-band frequency (7.3 GHz). This channel creates the opportunity to have a better screening for Radio Frequency Interference (RFI) and could eventually lead to improved soil moisture retrievals. The soil moisture retrievals from AMSR-2 we present here use the Land Parameter Retrieval Model (LPRM) in combination with a new radio frequency interference masking method. We used observations of the multi-frequency microwave radiometer onboard the Tropical Rainfall Measuring Mission (TRMM) satellite to intercalibrate the brightness temperatures in order to improve consistency between AMSR-E and AMSR-2. Several scenarios to accomplish synergy between the AMSR-E and AMSR-2 soil moisture products were evaluated. A global comparison of soil moisture retrievals against ERA Interim re-analysis soil moisture demonstrates the need for an intercalibration procedure. Several different scenarios based on filtering were tested and the impact on the soil moisture retrievals was evaluated against two independent reference soil moisture datasets (reanalysis and in situ soil moisture) that cover the observation periods of the AMSR-E and AMSR-2 sensors. Results show a high degree of consistency between both satellite products and two independent reference products for the soil moisture products. In addition, the added value of an additional frequency for RFI detection is demonstrated within this study with a reduction of the total contaminated pixels in the 6.9 GHz of 66% for horizontal observations and even 85% for vertical observations when 7.3 and 10

  17. Galvanic Cell Type Sensor for Soil Moisture Analysis.

    PubMed

    Gaikwad, Pramod; Devendrachari, Mruthyunjayachari Chattanahalli; Thimmappa, Ravikumar; Paswan, Bhuneshwar; Raja Kottaichamy, Alagar; Makri Nimbegondi Kotresh, Harish; Thotiyl, Musthafa Ottakam

    2015-07-21

    Here we report the first potentiometric sensor for soil moisture analysis by bringing in the concept of Galvanic cells wherein the redox energies of Al and conducting polyaniline are exploited to design a battery type sensor. The sensor consists of only simple architectural components, and as such they are inexpensive and lightweight, making it suitable for on-site analysis. The sensing mechanism is proved to be identical to a battery type discharge reaction wherein polyaniline redox energy changes from the conducting to the nonconducting state with a resulting voltage shift in the presence of soil moisture. Unlike the state of the art soil moisture sensors, a signal derived from the proposed moisture sensor is probe size independent, as it is potentiometric in nature and, hence, can be fabricated in any shape or size and can provide a consistent output signal under the strong aberration conditions often encountered in soil moisture analysis. The sensor is regenerable by treating with 1 M HCl and can be used for multiple analysis with little read out hysteresis. Further, a portable sensor is fabricated which can provide warning signals to the end user when the moisture levels in the soil go below critically low levels, thereby functioning as a smart device. As the sensor is inexpensive, portable, and potentiometric, it opens up avenues for developing effective and energy efficient irrigation strategies, understanding the heat and water transfer at the atmosphere-land interface, understanding soil mechanics, forecasting the risk of natural calamities, and so on. PMID:26098202

  18. Advanced sensors and instrumentation

    NASA Technical Reports Server (NTRS)

    Calloway, Raymond S.; Zimmerman, Joe E.; Douglas, Kevin R.; Morrison, Rusty

    1990-01-01

    NASA is currently investigating the readiness of Advanced Sensors and Instrumentation to meet the requirements of new initiatives in space. The following technical objectives and technologies are briefly discussed: smart and nonintrusive sensors; onboard signal and data processing; high capacity and rate adaptive data acquisition systems; onboard computing; high capacity and rate onboard storage; efficient onboard data distribution; high capacity telemetry; ground and flight test support instrumentation; power distribution; and workstations, video/lighting. The requirements for high fidelity data (accuracy, frequency, quantity, spatial resolution) in hostile environments will continue to push the technology developers and users to extend the performance of their products and to develop new generations.

  19. Moisture sensors 1980 on-line roles increase

    SciTech Connect

    Bailey, S.J.

    1980-09-01

    A review of on- and off-line moisture and humidity sensors covers instruments based on the capacitive principle such as Panametrics' Aquamax II and those developed by Ondyne, Moisture Control Systems, Phys-Chemical Research Corp., Shaw Instruments, and Diversified Engineering; instruments based on the microwave plus gamma and nuclear plus gamma radiation principles such as those by Kay-Ray and Ohmart Corp., respectively; sensors based on the saturated salt principle such as Foxboro's self-heated lithium chloride sensor; Kahn and Co.'s electrolytic hygrometer for monitoring the moisture content of pure gases or gas mixtures in natural gas transmissions; the Ohaus gravimetric instrument; microprocessor-based titrators by Foxboro Analytical and Photovolt Corp.; instruments which sense moving web moisture such as Beckman Instrument's Hygroline System HMP20 and Hy-Cal Engineering's sensor; IR stack gas analyzers by Anarad Inc. and Moisture Systems Corp.; optical hygrometers by EG and G and General Eastern; Panametrics' Model 4000 moisture computer; and Du Pont's standard 560 analyzer and new controller.

  20. Field testing a microwave moisture sensor for real-time kernel moisture content monitoring during peanut drying

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The present peanut drying process lacks the capability of kernel moisture content determination in real-time. A microwave moisture sensor, developed within USDA ARS, affords the capability of in-shell kernel moisture content determination; thus, providing a means for monitoring kernel moisture conte...

  1. Moisture content measurements of moss (Sphagnum spp.) using commercial sensors

    USGS Publications Warehouse

    Yoshikawa, K.; Overduin, P.P.; Harden, J.W.

    2004-01-01

    Sphagnum (spp.) is widely distributed in permafrost regions around the arctic and subarctic. The moisture content of the moss layer affects the thermal insulative capacity and preservation of permafrost. It also controls the growth and collapse history of palsas and other peat mounds, and is relevant, in general terms, to permafrost thaw (thermokarst). In this study, we test and calibrate seven different soil moisture sensors for measuring the moisture content of Sphagnum moss under laboratory conditions. The soil volume to which each probe is sensitive is one of the important parameters influencing moisture measurement, particularly in a heterogeneous medium such as moss. Each sensor has a unique response to changing moisture content levels, solution salinity, moss bulk density and to the orientation (structure) of the Sphagnum relative to the sensor. All of the probes examined here require unique polynomial calibration equations to obtain moisture content from probe output. We provide polynomial equations for dead and live Sphagnum moss (R2 > 0.99. Copyright ?? 2004 John Wiley & Sons, Ltd.

  2. SoilNet - A Zigbee based soil moisture sensor network

    NASA Astrophysics Data System (ADS)

    Bogena, H. R.; Weuthen, A.; Rosenbaum, U.; Huisman, J. A.; Vereecken, H.

    2007-12-01

    Soil moisture plays a key role in partitioning water and energy fluxes, in providing moisture to the atmosphere for precipitation, and controlling the pattern of groundwater recharge. Large-scale soil moisture variability is driven by variation of precipitation and radiation in space and time. At local scales, land cover, soil conditions, and topography act to redistribute soil moisture. Despite the importance of soil moisture, it is not yet measured in an operational way, e.g. for a better prediction of hydrological and surface energy fluxes (e.g. runoff, latent heat) at larger scales and in the framework of the development of early warning systems (e.g. flood forecasting) and the management of irrigation systems. The SoilNet project aims to develop a sensor network for the near real-time monitoring of soil moisture changes at high spatial and temporal resolution on the basis of the new low-cost ZigBee radio network that operates on top of the IEEE 802.15.4 standard. The sensor network consists of soil moisture sensors attached to end devices by cables, router devices and a coordinator device. The end devices are buried in the soil and linked wirelessly with nearby aboveground router devices. This ZigBee wireless sensor network design considers channel errors, delays, packet losses, and power and topology constraints. In order to conserve battery power, a reactive routing protocol is used that determines a new route only when it is required. The sensor network is also able to react to external influences, e.g. such as rainfall occurrences. The SoilNet communicator, routing and end devices have been developed by the Forschungszentrum Juelich and will be marketed through external companies. We will present first results of experiments to verify network stability and the accuracy of the soil moisture sensors. Simultaneously, we have developed a data management and visualisation system. We tested the wireless network on a 100 by 100 meter forest plot equipped with 25

  3. Advanced border monitoring sensor system

    NASA Astrophysics Data System (ADS)

    Knobler, Ronald A.; Winston, Mark A.

    2008-04-01

    McQ has developed an advanced sensor system tailored for border monitoring that has been delivered as part of the SBInet program for the Department of Homeland Security (DHS). Technology developments that enhance a broad range of features are presented in this paper, which address the overall goal of the system to improving unattended ground sensor system capabilities for border monitoring applications. Specifically, this paper addresses a system definition, communications architecture, advanced signal processing to classify targets, and distributed sensor fusion processing.

  4. Evaluation of an in situ Grain Moisture Sensor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grain storage managers could improve the quality of stored grain if they could directly monitor grain moisture content in storage bins, which is a key indicator of stored grain quality and an early indicator of deterioration. However, the necessary sensors are not commercially available. A new capa...

  5. Wheat moisture measurement with a fringing field capacitive sensor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grain storage managers could improve the quality of stored grain if they could directly monitor stored grain moisture content, which is a key indicator of stored grain quality and an early indicator of deterioration. However, currently available sensors are too expensive and lack the necessary relia...

  6. Derivation of soil moisture sensing depth from microwave satellite sensors

    NASA Astrophysics Data System (ADS)

    de Jeu, Richard; Holmes, Thomas

    2015-04-01

    Soil moisture retrievals from low frequency passive microwave satellite sensors (e.g. ESAs current Soil Moisture Ocean Salinity mission (SMOS)) are assumed to estimate spatially explicit soil moisture content of the first centimeters. However, the exact microwave sensing depth and the dynamic nature of the sensing depth at satellite grid scale is still to a large degree unknown. A more reliable estimation of the sensing depth would greatly improve the utility of microwave soil moisture retrievals. Validation activities could be fine-tuned, algorithms could be improved, and modeling applications could match observations to more optimal model depth. In addition to all this, soil moisture sensing depth information is essential for the development of a consistent fundamental soil moisture climate data record. With the availability of multiple polar orbiting satellites with multi-frequency microwave radiometers it has now become possible to study the microwave sensing depth as it manifests itself at observational scales. The approach uses the differences in timing between the diurnal temperature cycle (DTC) of microwave observations and thermal infrared observations as a basis to calculate the sensing depth. Using an intercalibrated multi sensor microwave data set and geostationary thermal infrared observations this approach is used to evaluate sensing depth at several microwave frequencies relevant for soil moisture retrieval. Field data in combination with an integrated thermodynamic hydrological microwave model are then used to develop guidelines for a dynamic sensing depth algorithm. The key advantage of this approach is its global applicability, providing timely and consistent information on sensing depth for different satellite soil moisture datasets.

  7. Soil moisture sensor intercomparisons at the SMAP marena in situ testbed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In May 2010, a soil moisture sensor intercomparison study was begun in Marena, Oklahoma. This effort is designed to serve as a foundation for incorporating diverse soil moisture networks into the Soil Moisture Active Passive (SMAP) Calibration and Validation program. Various soil moisture sensors, w...

  8. Satellite soil moisture for advancing our understanding of earth system processes and climate change

    NASA Astrophysics Data System (ADS)

    Dorigo, Wouter; de Jeu, Richard

    2016-06-01

    Soil moisture products obtained from active and passive microwave satellites have reached maturity during the last decade (De Jeu and Dorigo, 2016): On the one hand, research algorithms that were initially applied to sensors designed for other purposes, e.g., for measuring wind speed (e.g. the Advanced Scatterometer (ASCAT)), sea ice, or atmospheric parameters (e.g. the TRMM Microwave Imager (TMI) and the Advanced Microwave Scanning Radiometer - Earth Observing System AMSR-E), have developed into fully operational products. On the other hand, dedicated soil moisture satellite missions were designed and launched by ESA (the Soil Moisture Ocean Salinity (SMOS) mission) and NASA (the Soil Moisture Active Passive (SMAP) mission).

  9. A root moisture sensor for plants in microgravity.

    PubMed

    Clark, G J; Neville, G E; Dreschel, T W

    1994-11-01

    Development of components for bioregenerative life-support systems is a vital step toward long-term space exploration. The culturing of plants in a microgravity environment may be optimized by the use of appropriate sensors and controllers. This paper describes a sensor developed for determining the amount of fluid (nutrient solution) available on the surface of a porous ceramic nutrient delivery substrate to the roots of conventional crop plants. The sensor is based on the change in thermal capacitance and thermal conductance near the surface as the moisture content changes. The sensor could be employed as a data acquisition and control sensor to support the automated monitoring of plants grown in a microgravity environment. PMID:11540184

  10. Moisture Sensor for Sulfur Hexafluoride (SF6)-filled Circuit Breakers

    SciTech Connect

    Sauers, I.

    2001-04-27

    Measurements at ORNL were made on the Kahn moisture sensor which Doble Engineering wants to evaluate for use in SF{sub 6} circuit breakers. Test conducted at ORNL indicate that vacuum conditions, as might be found in SF{sub 6} circuit breakers prior to filling with SF{sub 6}, could lead to significant changes in calibration, resulting in erroneous readings of moisture content. Similar effects might also be observed in cases where SF{sub 6} byproducts are present, due the reactivity of some of these byproducts with water.

  11. Advancing Sensor Web Interoperability

    SciTech Connect

    Shankar, Mallikarjun; Gorman, Bryan L.; Smith, Cyrus M.

    2005-01-01

    SensorNet is a framework being developed at Oak Ridge National Laboratory to tie together sensor data from all over the country to create a real-time detection and alert system for various threats, whether they are chemical, radiological, biological, nuclear, or explosive.

  12. A comparison of soil moisture sensors for space flight applications

    NASA Technical Reports Server (NTRS)

    Norikane, J. H.; Prenger, J. J.; Rouzan-Wheeldon, D. T.; Levine, H. G.

    2005-01-01

    Plants will be an important part of future long-term space missions. Automated plant growth systems require accurate and reliable methods of monitoring soil moisture levels. There are a number of different methods to accomplish this task. This study evaluated sensors using the capacitance method (ECH2O), the heat-pulse method (TMAS), and tensiometers, compared to soil water loss measured gravimetrically in a side-by-side test. The experiment monitored evaporative losses from substrate compartments filled with 1- to 2-mm baked calcinated clay media. The ECH2O data correlated well with the gravimetric measurements, but over a limited range of soil moisture. The averaged TMAS sensor data overstated soil moisture content levels. The tensiometer data appeared to track evaporative losses in the 0.5- to 2.5-kPa range of matric potential that corresponds to the water content needed to grow plants. This small range is characteristic of large particle media, and thus high-resolution tensiometers are required to distinguish changing moisture contents in this range.

  13. A comparison of soil moisture sensors for space flight applications.

    PubMed

    Norikane, J H; Prenger, J J; Rouzan-Wheeldon, D T; Levine, H G

    2005-03-01

    Plants will be an important part of future long-term space missions. Automated plant growth systems require accurate and reliable methods of monitoring soil moisture levels. There are a number of different methods to accomplish this task. This study evaluated sensors using the capacitance method (ECH2O), the heat-pulse method (TMAS), and tensiometers, compared to soil water loss measured gravimetrically in a side-by-side test. The experiment monitored evaporative losses from substrate compartments filled with 1- to 2-mm baked calcinated clay media. The ECH2O data correlated well with the gravimetric measurements, but over a limited range of soil moisture. The averaged TMAS sensor data overstated soil moisture content levels. The tensiometer data appeared to track evaporative losses in the 0.5- to 2.5-kPa range of matric potential that corresponds to the water content needed to grow plants. This small range is characteristic of large particle media, and thus high-resolution tensiometers are required to distinguish changing moisture contents in this range. PMID:15934177

  14. Trace moisture detection in oil filled transformer by ceramic sensor

    NASA Astrophysics Data System (ADS)

    Saha, Debdulal; Sengupta, K.

    2015-02-01

    This paper reports on the suitability of thin film nano porous γ-alumina sensor for sensing parts per million (ppm) moisture present in transformer oil. Transformer oil degrades slowly by weathering, causing dielectric break down voltage of the oil to fall down. For improving this break down voltage, water must be removed from the transformer oil. Flash point of the transformer oil ranges from 150°C to 200°C.When the oil is slowly heated up to 75°C water vapour comes out from oil which is detected by ceramic sensor. The sensor is prepared from organo-metallic precursor by sol-gel process. Gold coated α-alumina substrate was dipped within the alumina hydra-sol and a thin film of γ-alumina formed on the substrate. The sensor capacitance was measured as a function of ppm moisture level. The circuit produces an output voltage which is precisely related to the absolute value of the capacitance of the dielectric material. In order to improve the sensitivity, parallel electrode structure was patterned on the nano porous dielectric. The response is sufficiently linear in extremely low ppm level moisture. A prototype hygrometer was built for detection of trace moisture in transformer oil. Porous alumina can be produced at a relatively low cost and in a variety of structural configurations. Sol- gel processing of alumina allows superior control on pore morphology, phase formation, purity and product microstructure compared to the more traditional techniques like Anodic oxidation of alumina sheets, tape cast by different sizes of alumina powder etc.

  15. Miniaturized nondestructive microwave sensor for chickpea moisture measurement

    NASA Astrophysics Data System (ADS)

    Abegaonkar, Mahesh P.; Karekar, R. N.; Aiyer, R. C.

    1999-07-01

    A miniaturized microstrip ring resonator (MRR) 1 in.×1 in. resonating at fro=10.27 GHz was used as a nondestructive moisture sensor for chickpea kernels (Cicer arietinum L.) for ease in loading and unloading. The change in the resonant frequency (Δfr) of the MRR is a measure of the amount of moisture in the overlaid kernel. The percentage of moisture (M) was varied from 0% (dry) to ˜50% (fully soaked) calculated on a wet weight basis. Δfr increased with M, although not linearly. Three regions were observed in the sensitivity curve. The first region extended from 0%-12%, the central region from 12%-43%, and the saturation region from 43%-50% in moisture content. In the central region the observed Δfr was 574 MHz, whereas in the first and third regions it was 44 and 55 MHz, respectively. The regions in the sensitivity curves indicate different dominant phenomena. A small scatter was observed in the first region, which increased with the increasing percent of moisture content.

  16. Monitoring Land Surface Soil Moisture from Space with in-Situ Sensors Validation: The Huntsville Example

    NASA Technical Reports Server (NTRS)

    Wu, Steve Shih-Tseng

    1997-01-01

    Based on recent advances in microwave remote sensing of soil moisture and in pursuit of research interests in areas of hydrology, soil climatology, and remote sensing, the Center for Hydrology, Soil Climatology, and Remote Sensing (HSCARS) conducted the Huntsville '96 field experiment in Huntsville, Alabama from July 1-14, 1996. We, researchers at the Global Hydrology and Climate Center's MSFC/ES41, are interested in using ground-based microwave sensors, to simulate land surface brightness signatures of those spaceborne sensors that were in operation or to be launched in the near future. The analyses of data collected by the Advanced Microwave Precipitation Radiometer (AMPR) and the C-band radiometer, which together contained five frequencies (6.925,10.7,19.35, 37.1, and 85.5 GHz), and with concurrent in-situ collection of surface cover conditions (surface temperature, surface roughness, vegetation, and surface topology) and soil moisture content, would result in a better understanding of the data acquired over land surfaces by the Special Sensor Microwave Imager (SSM/I), the Tropical Rainfall Measuring Mission Microwave Imager (TMI), and the Advanced Microwave Scanning Radiometer (AMSR), because these spaceborne sensors contained these five frequencies. This paper described the approach taken and the specific objective to be accomplished in the Huntsville '97 field experiment.

  17. Soil moisture sensor calibration for organic soil surface layers

    NASA Astrophysics Data System (ADS)

    Bircher, S.; Andreasen, M.; Vuollet, J.; Vehviläinen, J.; Rautiainen, K.; Jonard, F.; Weihermüller, L.; Zakharova, E.; Wigneron, J.-P.; Kerr, Y. H.

    2015-12-01

    This paper's objective is to present generic calibration functions for organic surface layers derived for the soil moisture sensors Decagon ECH2O 5TE and Delta-T ThetaProbe ML2x, using material from northern regions, mainly from the Finish Meteorological Institute's Arctic Research Center in Sodankylä and the study area of the Danish Center for Hydrology HOBE. For the Decagon 5TE sensor such a function is currently not reported in literature. Data were compared with measurements from underlying mineral soils including laboratory and field measurements. Shrinkage and charring during drying were considered. For both sensors all field and lab data showed consistent trends. For mineral layers with low soil organic matter (SOM) content the validity of the manufacturer's calibrations was demonstrated. Deviating sensor outputs in organic and mineral horizons were identified: for the Decagon 5TE apparent relative permittivities at a given moisture content decreased for increased SOM content, which was attributed to an increase of bound water in organic materials with large surface areas compared to the studied mineral soils. ThetaProbe measurements from organic horizons showed stronger non-linearity in the sensor response and signal saturation in the high level data. The derived calibration fit functions between sensor response and volumetric water content hold for samples spanning a wide range of humus types with differing SOM characteristics. This strengthens confidence in their validity under various conditions, rendering them highly suitable for large-scale applications in remote sensing and land surface modeling studies. Agreement between independent Decagon 5TE and ThetaProbe time series from an organic surface layer at the Sodankylä site was significantly improved when the here proposed fit functions were used. Decagon 5TE data also well-reflected precipitation events. Thus, Decagon 5TE network data from organic surface layers at the Sodankylä and HOBE sites are

  18. Soil moisture sensor calibration for organic soil surface layers

    NASA Astrophysics Data System (ADS)

    Bircher, Simone; Andreasen, Mie; Vuollet, Johanna; Vehviläinen, Juho; Rautiainen, Kimmo; Jonard, François; Weihermüller, Lutz; Zakharova, Elena; Wigneron, Jean-Pierre; Kerr, Yann H.

    2016-04-01

    This paper's objective is to present generic calibration functions for organic surface layers derived for the soil moisture sensors Decagon ECH2O 5TE and Delta-T ThetaProbe ML2x, using material from northern regions, mainly from the Finnish Meteorological Institute's Arctic Research Center in Sodankylä and the study area of the Danish Center for Hydrology (HOBE). For the Decagon 5TE sensor such a function is currently not reported in the literature. Data were compared with measurements from underlying mineral soils including laboratory and field measurements. Shrinkage and charring during drying were considered. For both sensors all field and lab data showed consistent trends. For mineral layers with low soil organic matter (SOM) content the validity of the manufacturer's calibrations was demonstrated. Deviating sensor outputs in organic and mineral horizons were identified. For the Decagon 5TE, apparent relative permittivities at a given moisture content decreased for increased SOM content, which was attributed to an increase of bound water in organic materials with large specific surface areas compared to the studied mineral soils. ThetaProbe measurements from organic horizons showed stronger nonlinearity in the sensor response and signal saturation in the high-level data. The derived calibration fit functions between sensor response and volumetric water content hold for samples spanning a wide range of humus types with differing SOM characteristics. This strengthens confidence in their validity under various conditions, rendering them highly suitable for large-scale applications in remote sensing and land surface modeling studies. Agreement between independent Decagon 5TE and ThetaProbe time series from an organic surface layer at the Sodankylä site was significantly improved when the here-proposed fit functions were used. Decagon 5TE data also well-reflected precipitation events. Thus, Decagon 5TE network data from organic surface layers at the Sodankylä and

  19. Orbiting passive microwave sensor simulation applied to soil moisture estimation

    NASA Technical Reports Server (NTRS)

    Newton, R. W. (Principal Investigator); Clark, B. V.; Pitchford, W. M.; Paris, J. F.

    1979-01-01

    A sensor/scene simulation program was developed and used to determine the effects of scene heterogeneity, resolution, frequency, look angle, and surface and temperature relations on the performance of a spaceborne passive microwave system designed to estimate soil water information. The ground scene is based on classified LANDSAT images which provide realistic ground classes, as well as geometries. It was determined that the average sensitivity of antenna temperature to soil moisture improves as the antenna footprint size increased. Also, the precision (or variability) of the sensitivity changes as a function of resolution.

  20. Advanced MEMS spectral sensor for the NIR

    NASA Astrophysics Data System (ADS)

    Antila, Jarkko E.; Kantojärvi, Uula; Mäkynen, Jussi; Tammi, Matti; Suhonen, Janne

    2015-02-01

    Near Infrared (NIR) spectrometers are widely used in many fields to measure material content, such as moisture, fat and protein in grains, foodstuffs and pharmaceutical powders. These fields include applications where only highly miniaturized and robust NIR sensors can be used due to small usable space, weight requirements and/or hostile working environment. Handheld devices for material inspection, online process automation and automotive industry introduce requirements for size, robustness and cost, which is currently difficult to meet. In this paper we present an advanced spectral sensor based on a tunable Microelectromechanical (MEMS) Fabry-Perot Interferometer. The sensor is fibercoupled, weighs 125 grams and fits to an envelope of 25x55x55 mm3. Three types of sensors cover the wavelength ranges from 1.35-1.7 μm, 1.55-2.0 μm and 1.7-2.2 μm, utilizing only a single pixel extended InGaAs detector, avoiding the expensive linear array detectors. We describe the design, principle of operation and calibration methods together with the control schemes. Some environmental tests are described and their results and finally application measurement results are presented along with discussion and conclusions.

  1. Advances In Optical Fiber Sensors

    NASA Astrophysics Data System (ADS)

    Cole, J. H.; Giallorenzi, T. G.; Bucaro, J. A.

    1981-07-01

    Over the past several years, a new non-communication optical fiber application has emerged. This application utilizes optical fibers for sensing. Initial interest centered around rate rotation sensing. Since that time, however, acoustic, magnetic, and temperature sensing utilizing optical fibers has evolved into a viable research effort with significant potential payoff. As an example, laboratory fiber optic acoustic sensors now rival the best sensitivity obtained with piezoelectric ceramics. These sensors possess a unique geometric versatility previously unavailable. In conjunction with the Defense Advanced Research Projects Agency (DARPA), the Navy has begun a Fiber Optic Sensor System (FOSS) program to develop associated technology necessary to realize these sensors. Substantial effort is ongoing at the Naval Research Laboratory (NRL) and other Navy laboratories with considerable contractual effort from universities and industry. This paper reviews the status of the FOSS program.

  2. Advances, experiences, and prospects of the International Soil Moisture Network

    NASA Astrophysics Data System (ADS)

    Dorigo, W.; van Oevelen, P. J.; Drusch, M.; Wagner, W.; Scipal, K.; Mecklenburg, S.

    2012-12-01

    In 2009, the International Soil Moisture Network (ISMN; http:www.ipf.tuwien.ac.at) was initiated as a platform to support calibration and validation of soil moisture products from remote sensing and land surface models, and to advance studies on the behavior of soil moisture over space and time. This international initiative is fruit of continuing coordinative efforts of the Global Energy and Water Cycle Experiment (GEWEX) in cooperation with the Group of Earth Observation (GEO) and the Committee on Earth Observation Satellites (CEOS). The decisive financial incentive was given by the European Space Agency (ESA) who considered the establishment of the network critical for optimizing the soil moisture products from the Soil Moisture and Ocean Salinity (SMOS) mission. The ISMN collects and harmonizes ground-based soil moisture data sets from a large variety of individually operating networks and makes them available through a centralized data portal. Meanwhile, almost 6000 soil moisture data sets from over 1300 sites, distributed among 34 networks worldwide, are contained in the database. The steadily increasing number of organizations voluntarily contributing to the ISMN, and the rapidly increasing number of studies based on the network show that the portal has been successful in reaching its primary goal to promote easy data accessibility to a wide variety of users. Recently, several updates of the system were performed to keep up with the increasing data amount and traffic, and to meet the requirements of many advanced users. Many datasets from operational networks (e.g., SCAN, the US Climate Reference Network, COSMOS, and ARM) are now assimilated and processed in the ISMN on a fully automated basis in near-real time. In addition, a new enhanced quality control system is currently being implemented. This presentation gives an overview of these recent developments, presents some examples of important scientific results based on the ISMN, and sketches an outlook for

  3. Estimation of building material moisture using non-invasive TDR sensors

    NASA Astrophysics Data System (ADS)

    Suchorab, Zbigniew; Sobczuk, Henryk; Łagód, Grzegorz

    2016-07-01

    The article presents the noninvasive attempt to measure moisture of building materials with the use of electric methods. Comparing to the other techniques of moisture detection like chemical or physical, the electric methods enable quick moisture estimation and they seem to be a suitable solution to monitor moisture changes. Most of electric moisture meters are the capacitance and resistance sensors. A perspective technique to determine moisture of building materials and barriers is Time Domain Reflectometry (TDR) method. This method has been successfully applied for moisture determination of the soils and since a few years has been used to measure moisture of building materials. The attempts to measure moisture of building materials require modification of traditional TDR sensor construction and extra calibration procedures. Sensors applied for building materials, comparing to the traditional ones are noninvasive. The advantages of surface sensors proposed in this article are the following: no influence on material structure, easier sample preparation for laboratory measurements, good possibility to apply for in-situ measurements. Major disadvantage of the described sensors is the difficulty of outgoing sensor signal interpretation and thus the possibility of the increase of measurement uncertainty. Anyhow it must be underlined that proposed in the article sensor constructions seem to be a balanced alternative for quick moisture detection.

  4. Advances in Remote Sensing of Vegetation Merging NDVI, Soil Moisture, and Chlorophyll Fluorescence

    NASA Astrophysics Data System (ADS)

    Tucker, Compton

    2016-04-01

    I will describe an advance in remote sensing of vegetation in the time domain that combines simultaneous measurements of the normalized difference vegetation index, soil moisture, and chlorophyll fluorescence, all from different satellite sensors but acquired for the same areas at the same time step. The different sensor data are MODIS NDVI data from both Terra and Aqua platforms, soil moisture data from SMOS & SMP (aka SMAP but with only the passive radiometer), and chlorophyll fluorescence data from GOME-2. The complementary combination of these data provide important crop yield information for agricultural production estimates at critical phenological times in the growing season, provide a scientific basis to map land degradation, and enable quantitative determination of the end of the growing season in temperate zones.

  5. Inter-comparison of soil moisture sensors from the soil moisture active passive marena Oklahoma in situ sensor testbed (SMAP-MOISST)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The diversity of in situ soil moisture network protocols and instrumentation led to the development of a testbed for comparing in situ soil moisture sensors. Located in Marena, Oklahoma on the Oklahoma State University Range Research Station, the testbed consists of four base stations. Each station ...

  6. A sensor array system for monitoring moisture dynamics inunsaturated soil

    SciTech Connect

    Salve, R.; Cook, P.J.

    2007-05-15

    To facilitate investigations of moisture dynamics inunsaturated soil, we have developed a technique to qualitatively monitorpatterns of saturation changes. Field results suggest that this device,the sensor array system (SAS), is suitable for determining changes inrelative wetness along vertical soil profiles. The performance of theseprobes was compared with that of the time domain reflectometry (TDR)technique under controlled and field conditions. Measurements from bothtechniques suggest that by obtaining data at high spatial and temporalresolution, the SAS technique was effective in determining patterns ofsaturation changes along a soil profile. In addition, hardware used inthe SAS technique was significantly cheaper than the TDR system, and thesensor arrays were much easier to install along a soilprofile.

  7. Recent advances in (soil moisture) triple collocation analysis

    NASA Astrophysics Data System (ADS)

    Gruber, A.; Su, C.-H.; Zwieback, S.; Crow, W.; Dorigo, W.; Wagner, W.

    2016-03-01

    To date, triple collocation (TC) analysis is one of the most important methods for the global-scale evaluation of remotely sensed soil moisture data sets. In this study we review existing implementations of soil moisture TC analysis as well as investigations of the assumptions underlying the method. Different notations that are used to formulate the TC problem are shown to be mathematically identical. While many studies have investigated issues related to possible violations of the underlying assumptions, only few TC modifications have been proposed to mitigate the impact of these violations. Moreover, assumptions, which are often understood as a limitation that is unique to TC analysis are shown to be common also to other conventional performance metrics. Noteworthy advances in TC analysis have been made in the way error estimates are being presented by moving from the investigation of absolute error variance estimates to the investigation of signal-to-noise ratio (SNR) metrics. Here we review existing error presentations and propose the combined investigation of the SNR (expressed in logarithmic units), the unscaled error variances, and the soil moisture sensitivities of the data sets as an optimal strategy for the evaluation of remotely-sensed soil moisture data sets.

  8. A new microstripline-type moisture sensor for heavily wet tea leaves

    NASA Astrophysics Data System (ADS)

    Okamura, Seichi; Zhang, Yangjun; Tsukamoto, Nobuhito

    2007-04-01

    This paper describes a new sensor for high moisture measurement in producing green tea. The sensor is based on the microwave transmission technique. It uses a microstripline, on which tea leaves under test are overlaid. A microwave signal at 3 GHz was transmitted along the line, and attenuation and phase shift of the wave were measured. The moisture content of the leaves was calculated by a new idea of using the ratio of two signals corresponding to the attenuation and the phase shift. The sensor measured a moisture content range from 155 to 320% on a dry basis.

  9. Advanced millimeter wave chemical sensor.

    SciTech Connect

    Gopalsami, N.

    1999-03-24

    This paper discusses the development of an advanced millimeter-wave (mm-wave) chemical sensor and its applications for environmental monitoring and arms control treaty verification. The purpose of this work is to investigate the use of fingerprint-type molecular rotational signatures in the mm-wave spectrum to sense airborne chemicals. The mm-wave spectrum to sense airborne chemicals. The mm-wave sensor, operating in the frequency range of 220-300 GHz, can work under all weather conditions and in smoky and dusty environments. The basic configuration of the mm-wave sensor is a monostatic swept-frequency radar consisting of a mm-wave sweeper, a hot-electron-bolometer or Schottky barrier detector, and a trihedral reflector. The chemical plume to be detected is situated between the transmitter/detector and the reflector. Millimeter-wave absorption spectra of chemicals in the plume are determined by measuring the swept-frequency radar return signals with and without the plume in the beam path. The problem of pressure broadening, which hampered open-path spectroscopy in the past, has been mitigated in this work by designing a fast sweeping source over a broad frequency range. The heart of the system is a Russian backward-wave oscillator (BWO) tube that can be tuned over 220-350 GHz. Using the Russian BWO tube, a mm-wave radar system was built and field-tested at the DOE Nevada Test Site at a standoff distance of 60 m. The mm-wave system detected chemical plumes very well; the detection sensitivity for polar molecules like methyl chloride was down to a concentration of 12 ppm.

  10. Field Evaluation of a New Sensor for Near-Surface Critical Zone Soil Moisture in Continuous Spatial Profile

    NASA Astrophysics Data System (ADS)

    Farrington, S.; Wood, T. E.; Cavaleri, M. A.; Reed, S.; Kimball, B. A.; Alonso-Rodríguez, A. M.; Farrington, E. S.

    2015-12-01

    A new sensor technology, the Profile Resolving In-situ Soil Moisture Sensor (PRISMS), offers the potential to advance understanding of coupled biogeochemical and hydrologic processes in the near subsurface critical zone by acquiring continuous vertical profiles of near surface soil moisture. We present results of comparing PRISMS acquired soil moisture data to data from arrays of conventional TDR soil moisture probes installed at the Tropical Responses to Altered Climate Experiment (TRACE) site in Luquillo, Puerto Rico. Tropical forests exchange more carbon dioxide with the atmosphere than any other biome on Earth. In the next 20 years, the tropics will experience unprecedented warming, yet there is exceedingly high uncertainty about their potential responses to this imminent climatic change. TRACE is being conducted to help elucidate how tropical forests will respond to increasing temperatures, by examining critical processes in the most biogeochemically active ecosystem components of tropical forests (i.e., leaves, roots, soil microbes). These processes are coupled to subsurface hydrology which PRISMS monitors by providing continuous spatial profiles of soil moisture content. Six PRISMS probes were installed in and around two experimental plots in the TRACE, alongside vertical arrays of conventional TDR soil moisture probes that perform discrete volume averaged measurements. Data are being collected to validate the performance of the new technology. Preliminary results from the continuously profiling 1-meter long PRISMS probes will be presented in comparison to spatially discrete measurements obtained using the conventional probes. Also presented will be a review of the installation procedures used and integration of the new sensors into the TRACE sensor network.

  11. Advanced high temperature heat flux sensors

    NASA Technical Reports Server (NTRS)

    Atkinson, W.; Hobart, H. F.; Strange, R. R.

    1983-01-01

    To fully characterize advanced high temperature heat flux sensors, calibration and testing is required at full engine temperature. This required the development of unique high temperature heat flux test facilities. These facilities were developed, are in place, and are being used for advanced heat flux sensor development.

  12. Wireless sensor network for monitoring soil moisture and weather conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A wireless sensor network (WSN) was developed and deployed in three fields to monitor soil water status and collect weather data for irrigation scheduling. The WSN consists of soil-water sensors, weather sensors, wireless data loggers, and a wireless modem. Soil-water sensors were installed at three...

  13. Capacitance Based Moisture Sensing for Microgravity Plant Modules: Sensor Design and Considerations

    NASA Technical Reports Server (NTRS)

    Schaber, Chad L.; Nurge, Mark; Monje, Oscar

    2011-01-01

    Life support systems for growing plants in microgravity should strive for providing optimal growing conditions and increased automation. Accurately tracking soil moisture content can forward both of these aims, so an attempt was made to instrument a microgravity growth module currently in development, the VEGGIE rooting pillow, in order to monitor moisture levels. Two electrode systems for a capacitance-based moisture sensor were tested. Trials with both types of electrodes showed a linear correlation between observed capacitance and water content over certain ranges of moisture within the pillows. Overall, both types of the electrodes and the capacitance-based moisture sensor are promising candidates for tracking water levels for microgravity plant growth systems.

  14. Moisture sensor based on evanescent wave light scattering by porous sol-gel silica coating

    DOEpatents

    Tao, Shiquan; Singh, Jagdish P.; Winstead, Christopher B.

    2006-05-02

    An optical fiber moisture sensor that can be used to sense moisture present in gas phase in a wide range of concentrations is provided, as well techniques for making the same. The present invention includes a method that utilizes the light scattering phenomenon which occurs in a porous sol-gel silica by coating an optical fiber core with such silica. Thus, a porous sol-gel silica polymer coated on an optical fiber core forms the transducer of an optical fiber moisture sensor according to an embodiment. The resulting optical fiber sensor of the present invention can be used in various applications, including to sense moisture content in indoor/outdoor air, soil, concrete, and low/high temperature gas streams.

  15. Soil moisture sensing via swept frequency based microwave sensors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate measurement of moisture content is a prime requirement in hydrological, geophysical, and biogeochemical research as well as for material characterization, process control, and irrigation efficiency in water limited regions. Within these areas, consideration of the surface area and associate...

  16. An Advanced Video Sensor for Automated Docking

    NASA Technical Reports Server (NTRS)

    Howard, Richard T.; Bryan, Thomas C.; Book, Michael L.; Roe, Fred (Technical Monitor)

    2001-01-01

    This paper describes the current developments in video-based sensors at the Marshall Space Flight Center. The Advanced Video Guidance Sensor is the latest in a line of video-based sensors designed for use in automated docking systems. The X-33, X-34, X-38, and X-40 are all designed to be unpiloted vehicles; such vehicles will require a sensor system that will provide adequate data for the vehicle to accomplish its mission. One of the primary tasks planned for re-usable launch vehicles is to resupply the space station. In order to approach the space station in a self-guided manner, the vehicle must have a reliable and accurate sensor system to provide relative position and attitude information between the vehicle and the space station. The Advanced Video Guidance Sensor is being designed and built to meet this requirement, as well as requirements for other vehicles docking to a variety of target spacecraft. The Advanced Video Guidance Sensor is being designed to allow range and bearing information to be measured at ranges up to 2 km. The sensor will measure 6-degree-of-freedom information (relative positions and attitudes) from approximately 40 meters all the way in to final contact (approximately 1 meter range). The sensor will have a data output rate of 20 Hz during tracking mode, and will be able to acquire a target within one half of a second. The prototype of the sensor will be near completion at the time of the conference.

  17. Validation of Advanced Microwave Scanning Radiometer Soil Moisture Products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Validation is an important and particularly challenging task for remote sensing of soil moisture. The key issue in the validation of soil moisture products is the disparity in spatial scales between satellite and in situ observations. Conventional measurements of soil moisture are made at a point wh...

  18. Developing a virtual sensor (VS) for mapping soil moisture at high spatial and temporal resolution

    NASA Astrophysics Data System (ADS)

    Hossain, A. K. M. Azad

    Mapping soil moisture at both high spatial and temporal resolution has not been possible due to lack of sensors with these combined capabilities. We transformed the Moderate Resolution Imaging Spectroradiometer (MODIS) into a virtual sensor (VS) for quantitative soil moisture mapping and monitoring at 1 km and 250 m resolution daily. The Vegetation Index (VI) - Land Surface Temperature (LST) triangle model was used as the governing algorithm for VS. We used a time series of 13 data sets from August 01, 2006 to November 06, 2006 of MODIS reflective and thermal imagery and AMSR-E Level 3 soil moisture imagery to develop the VS in the semi-arid environment of southeastern New Mexico. We used Synthetic Aperture Radar (SAR) derived soil moisture imagery for five corresponding dates of the MODIS/AMSR-E imagery to evaluate the performance of VS for soil moisture estimation along with near real time in situ soil moisture measurements. In situ soil moisture measurements, vegetation density/distribution maps, digital elevation model (DEM), soil type map and soil salinity measurements were used in both linear and non-linear numerical models with the Radarsat 1 SAR fine imagery. The numerical models based on multiple linear regressions improved soil moisture estimation for the entire study site. We found, however, that vegetation, soil type and elevation have stronger combined effect on microwave soil moisture remote sensing by non-linear regressions (neural networks). The accuracy of the soil moisture data was evaluated using Kappa statistics. A soil moisture prediction surface prepared by kriging the in situ soil moisture 2 measurements was used as the reference. We obtained the overall accuracy of 75.67% and 77.67% with a Kappa coefficient of 0.43 and 0.61 for the August 02 and November 06 data sets of 2006, respectively. We evaluated the application of VS generated soil moisture data in mapping the spatio-temporal variation in soil moisture in southeastern New Mexico. The

  19. Advanced Sensors and Applications Study (ASAS)

    NASA Technical Reports Server (NTRS)

    Chism, S. B.; Hughes, C. L.

    1976-01-01

    The present EOD requirements for sensors in the space shuttle era are reported with emphasis on those applications which were deemed important enough to warrant separate sections. The application areas developed are: (1) agriculture; (2) atmospheric corrections; (3) cartography; (4) coastal studies; (5) forestry; (6) geology; (7) hydrology; (8) land use; (9) oceanography; and (10) soil moisture. For each application area. The following aspects were covered: (1) specific goals and techniques, (2) individual sensor requirements including types, bands, resolution, etc.; (3) definition of mission requirements, type orbits, coverages, etc.; and (4) discussion of anticipated problem areas and solutions. The remote sensors required for these application areas include; (1) camera systems; (2) multispectral scanners; (3) microwave scatterometers; (4) synthetic aperture radars; (5) microwave radiometers; and (6) vidicons. The emphasis in the remote sensor area was on the evaluation of present technology implications about future systems.

  20. A sensor for the measurement of the moisture of undisturbed soil samples.

    PubMed

    Kitić, Goran; Crnojević-Bengin, Vesna

    2013-01-01

    This paper presents a very accurate sensor for the measurement of the moisture of undisturbed soil samples. The sensor relies on accurate estimation of the permittivity which is performed independently of the soil type, and a subsequent calibration. The sensor is designed as an upgrade of the conventional soil sampling equipment used in agriculture--the Kopecky cylinder. The detailed description of the device is given, and the method for determining soil moisture is explained in detail. Soil moisture of unknown test samples was measured with an absolute error below 0.0057 g/g, which is only 2.24% of the full scale output, illustrating the high accuracy of the sensor. PMID:23385404

  1. A Sensor for the Measurement of the Moisture of Undisturbed Soil Samples

    PubMed Central

    Kitić, Goran; Crnojević-Bengin, Vesna

    2013-01-01

    This paper presents a very accurate sensor for the measurement of the moisture of undisturbed soil samples. The sensor relies on accurate estimation of the permittivity which is performed independently of the soil type, and a subsequent calibration. The sensor is designed as an upgrade of the conventional soil sampling equipment used in agriculture—the Kopecky cylinder. The detailed description of the device is given, and the method for determining soil moisture is explained in detail. Soil moisture of unknown test samples was measured with an absolute error below 0.0057 g/g, which is only 2.24% of the full scale output, illustrating the high accuracy of the sensor. PMID:23385404

  2. Advanced Sensors for NASA's Exploration Missions

    NASA Technical Reports Server (NTRS)

    Lal, Ravindra B.; Clinton, R. G.; Frazier, Donald

    2005-01-01

    This paper presents a variety of advanced sensors needed for NASA's space exploration. The topics include: 1) The vision of the President of the United States of America for Space Exploration; 2) The report of the President's Commission on Implementation of United States Space Exploration Policy; 3) Exploration Systems Interim Report; 4) Major areas of sensor needs; 5) Classes of material; and 6) Variety of Sensors for Space Exploration.

  3. Advanced IRFPAs for next-generation sensors

    NASA Astrophysics Data System (ADS)

    Caulfield, John T.; Fletcher, Christopher L.; Graham, Roger W.; Patten, Elizabeth A.; Pham, Le T.; Pierce, Gregory; Scribner, Dean A.; Skele, Martins; Taylor, Scott M.; Trautfield, Walter C.

    2004-08-01

    Raytheon Vision Systems (RVS) has invented and demonstrated a new class of advanced focal plane arrays. These Advanced FPAs are sometimes called 3rd Generation or "Next Generation" FPAs because they have integrated onto the FPA the ability to sense multiple IR spectrums, have improved resolution and performance, and conduct image processing on the FPA ROIC. These next generation of FPAs are allowing more functionality and the detection of a more diverse set of data than previously possible with 2nd Gen FPAs. Examples and history of advanced next generation FPAs are reviewed including RVS"s Multispectral, Uncooled, Adaptive Sensors and other advanced sensors.

  4. Distributed sensor coordination for advanced energy systems

    SciTech Connect

    Tumer, Kagan

    2015-03-12

    Motivation: The ability to collect key system level information is critical to the safe, efficient and reliable operation of advanced power systems. Recent advances in sensor technology have enabled some level of decision making directly at the sensor level. However, coordinating large numbers of sensors, particularly heterogeneous sensors, to achieve system level objectives such as predicting plant efficiency, reducing downtime or predicting outages requires sophisticated coordination algorithms. Indeed, a critical issue in such systems is how to ensure the interaction of a large number of heterogenous system components do not interfere with one another and lead to undesirable behavior. Objectives and Contributions: The long-term objective of this work is to provide sensor deployment, coordination and networking algorithms for large numbers of sensors to ensure the safe, reliable, and robust operation of advanced energy systems. Our two specific objectives are to: 1. Derive sensor performance metrics for heterogeneous sensor networks. 2. Demonstrate effectiveness, scalability and reconfigurability of heterogeneous sensor network in advanced power systems. The key technical contribution of this work is to push the coordination step to the design of the objective functions of the sensors, allowing networks of heterogeneous sensors to be controlled. By ensuring that the control and coordination is not specific to particular sensor hardware, this approach enables the design and operation of large heterogeneous sensor networks. In addition to the coordination coordination mechanism, this approach allows the system to be reconfigured in response to changing needs (e.g., sudden external events requiring new responses) or changing sensor network characteristics (e.g., sudden changes to plant condition). Impact: The impact of this work extends to a large class of problems relevant to the National Energy Technology Laboratory including sensor placement, heterogeneous sensor

  5. AN ACTIVE-PASSIVE COMBINED ALGORITHM FOR HIGH SPATIAL RESOLUTION RETRIEVAL OF SOIL MOISTURE FROM SATELLITE SENSORS (Invited)

    NASA Astrophysics Data System (ADS)

    Lakshmi, V.; Mladenova, I. E.; Narayan, U.

    2009-12-01

    Soil moisture is known to be an essential factor in controlling the partitioning of rainfall into surface runoff and infiltration and solar energy into latent and sensible heat fluxes. Remote sensing has long proven its capability to obtain soil moisture in near real-time. However, at the present time we have the Advanced Scanning Microwave Radiometer (AMSR-E) on board NASA’s AQUA platform is the only satellite sensor that supplies a soil moisture product. AMSR-E coarse spatial resolution (~ 50 km at 6.9 GHz) strongly limits its applicability for small scale studies. A very promising technique for spatial disaggregation by combining radar and radiometer observations has been demonstrated by the authors using a methodology is based on the assumption that any change in measured brightness temperature and backscatter from one to the next time step is due primarily to change in soil wetness. The approach uses radiometric estimates of soil moisture at a lower resolution to compute the sensitivity of radar to soil moisture at the lower resolution. This estimate of sensitivity is then disaggregated using vegetation water content, vegetation type and soil texture information, which are the variables on which determine the radar sensitivity to soil moisture and are generally available at a scale of radar observation. This change detection algorithm is applied to several locations. We have used aircraft observed active and passive data over Walnut Creek watershed in Central Iowa in 2002; the Little Washita Watershed in Oklahoma in 2003 and the Murrumbidgee Catchment in southeastern Australia for 2006. All of these locations have different soils and land cover conditions which leads to a rigorous test of the disaggregation algorithm. Furthermore, we compare the derived high spatial resolution soil moisture to in-situ sampling and ground observation networks

  6. Description and testing of three moisture sensors for measuring surface wetness on carbonate building stones

    USGS Publications Warehouse

    See, R.B.; Reddy, M.M.; Martin, R.G.

    1988-01-01

    Three moisture sensors were tested as a means for determining the surface wetness on carbonate building stones exposed to conditions that produce deposition of moisture. A relative-humidity probe, a gypsum-coated circuit grid, and a limestone-block resistor were tested as sensors for determining surface wetness. Sensors were tested under laboratory conditions of constant relative humidity and temperature and also under on-site conditions of variable relative humidity and temperature for eight weeks at Newcomb, NY. Laboratory tests indicated that relative humidity alone did not cause sensors to become saturated with water. However, the rates of drying indicated by the sensors after an initial saturation were inversely related to the relative humidity. On-site testing of the relative-humidity probe and the gypsum-coated ciruit grid indicated that they respond to a diurnal wetting and drying cycle; the limestone-block resistor responded only to rainfall.

  7. Statistical evaluation of an array of soil moisture sensors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The study of large experimental units often requires complicated decisions regarding the number and location of sensors for data collection designed to characterize the experimental unit. Sensors are often arrayed spatially based on the assumption that the variation is closely associated with landsc...

  8. Advanced monolithic pixel sensors using SOI technology

    NASA Astrophysics Data System (ADS)

    Miyoshi, Toshinobu; Arai, Yasuo; Asano, Mari; Fujita, Yowichi; Hamasaki, Ryutaro; Hara, Kazuhiko; Honda, Shunsuke; Ikegami, Yoichi; Kurachi, Ikuo; Mitsui, Shingo; Nishimura, Ryutaro; Tauchi, Kazuya; Tobita, Naoshi; Tsuboyama, Toru; Yamada, Miho

    2016-07-01

    We are developing advanced pixel sensors using silicon-on-insulator (SOI) technology. A SOI wafer is used; top silicon is used for electric circuit and bottom silicon is used as a sensor. Target applications are high-energy physics, X-ray astronomy, material science, non-destructive inspection, medical application and so on. We have developed two integration-type pixel sensors, FPIXb and INTPIX7. These sensors were processed on single SOI wafers with various substrates in n- or p-type and double SOI wafers. The development status of double SOI sensors and some up-to-date test results of n-type and p-type SOI sensors are shown.

  9. Recent advances in (soil moisture) triple collocation analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To date, triple collocation (TC) analysis is one of the most important methods for the global scale evaluation of remotely sensed soil moisture data sets. In this study we review existing implementations of soil moisture TC analysis as well as investigations of the assumptions underlying the method....

  10. Recent Advances in Paper-Based Sensors

    PubMed Central

    Liana, Devi D.; Raguse, Burkhard; Gooding, J. Justin; Chow, Edith

    2012-01-01

    Paper-based sensors are a new alternative technology for fabricating simple, low-cost, portable and disposable analytical devices for many application areas including clinical diagnosis, food quality control and environmental monitoring. The unique properties of paper which allow passive liquid transport and compatibility with chemicals/biochemicals are the main advantages of using paper as a sensing platform. Depending on the main goal to be achieved in paper-based sensors, the fabrication methods and the analysis techniques can be tuned to fulfill the needs of the end-user. Current paper-based sensors are focused on microfluidic delivery of solution to the detection site whereas more advanced designs involve complex 3-D geometries based on the same microfluidic principles. Although paper-based sensors are very promising, they still suffer from certain limitations such as accuracy and sensitivity. However, it is anticipated that in the future, with advances in fabrication and analytical techniques, that there will be more new and innovative developments in paper-based sensors. These sensors could better meet the current objectives of a viable low-cost and portable device in addition to offering high sensitivity and selectivity, and multiple analyte discrimination. This paper is a review of recent advances in paper-based sensors and covers the following topics: existing fabrication techniques, analytical methods and application areas. Finally, the present challenges and future outlooks are discussed. PMID:23112667

  11. An overview of neural network applications for soil moisture retrieval from radar satellite sensors

    NASA Astrophysics Data System (ADS)

    Santi, E.; Paloscia, S.; Pettinato, S.

    2014-10-01

    Frequent and spatially distributed measurements of soil moisture (SMC), at different spatial scales, are advisable for all applications related to the environmental disciplines, such as climatology, meteorology, hydrology and agriculture. Satellite sensors operating in the low part of microwave spectrum are very suitable for this purpose, and their signals can be directly related to the moisture content of the observed surfaces, provided that all the contributions from soil and vegetation to the measured signal are properly accounted for. Among the algorithms used for the retrieval of SMC from both active (i.e. Synthetic Aperture Radar, SAR or real aperture radars) and passive (radiometers) microwave sensors, the artificial neural networks (ANN) represent the best compromise between accuracy and computation speed. ANN based algorithms have been developed at IFAC, and adapted to several radar and radiometric satellite sensors, in order to generate SMC products at different spatial resolutions, varying from hundreds of meters to tens of kilometers. These algorithms, which use the ANN techniques for inverting theoretical and semi-empirical models, such as Advanced Integral Equation (AIEM), Oh models, and Radiative transfer Theory (RTT), have been adapted to the C-band acquisitions from SAR (Envisat/ASAR) and real aperture radar (ASCAT) and to the X-band SAR acquisitions of Cosmo-SkyMed and TerraSAR-X. Moreover, a specific ANN algorithm has also been implemented for the L-band active and passive acquisitions of the incoming SMAP mission. The latter satellite will carry onboard simultaneously one radar and one radiometer operating at the same frequency, but with different spatial resolutions (3 and 40 km, respectively). Large datasets of co-located satellite acquisitions and direct SMC measurements on several test sites located worldwide have been used along with simulations derived from forward electromagnetic models for setting up, training and validating these

  12. Observation of soil moisture variability in agricultural and grassland field soils using a wireless sensor network

    NASA Astrophysics Data System (ADS)

    Priesack, Eckart; Schuh, Max

    2014-05-01

    Soil moisture dynamics is a key factor of energy and matter exchange between land surface and atmosphere. Therefore long-term observation of temporal and spatial soil moisture variability is important in studying impacts of climate change on terrestrial ecosystems and their possible feedbacks to the atmosphere. Within the framework of the network of terrestrial environmental observatories TERENO we installed at the research farm Scheyern in soils of two fields (of ca. 5 ha size each) the SoilNet wireless sensor network (Biogena et al. 2010). The SoilNet in Scheyern consists of 94 sensor units, 45 for the agricultural field site and 49 for the grassland site. Each sensor unit comprises 6 SPADE sensors, two sensors placed at the depths 10, 30 and 50 cm. The SPADE sensor (sceme.de GmbH, Horn-Bad Meinberg Germany) consists of a TDT sensor to estimate volumetric soil water content from soil electrical permittivity by sending an electromagnetic signal and measuring its propagation time, which depends on the soil dielectric properties and hence on soil water content. Additionally the SPADE sensor contains a temperature sensor (DS18B20). First results obtained from the SoilNet measurements at both fields sites will be presented and discussed. The observed high temporal and spatial variability will be analysed and related to agricultural management and basic soil properties (bulk density, soil texture, organic matter content and soil hydraulic characteristics).

  13. The SMAP In Situ Soil Moisture Sensor Testbed: Comparing in situ sensors for satellite validation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One of the most valuable tools in validating satellite based soil moisture estimates, such as those from the Soil Moisture Active Passive (SMAP) mission are large scale in situ networks. Global validation involves networks operated by many different organizations. Existing in situ soil moisture netw...

  14. Development of a Moisture-in-Solid-Insulation Sensor for Power Transformers

    PubMed Central

    García, Belén; García, Diego; Robles, Guillermo

    2015-01-01

    Moisture is an important variable that must be kept under control to guarantee a safe operation of power transformers. Because of the hydrophilic character of cellulose, water mainly remains in the solid insulation, while just a few parts per million are dissolved in oil. The distribution of moisture between paper and oil is not static, but varies depending on the insulation temperature, and thus, water migration processes take place continuously during transformers operation. In this work, a sensor is presented that allows the determination of the moisture content of the transformer solid insulation in the steady state and during the moisture migration processes. The main objective of the design is that the electrodes of the sensor should not obstruct the movement of water from the solid insulation to the oil, so the proposed prototype uses a metallic-mesh electrode to do the measurements. The measurement setup is based on the characterization of the insulation dielectric response by means of the frequency dielectric spectroscopy (FDS) method. The sensitivity of the proposed sensor has been tested on samples with a moisture content within 1% to 5%, demonstrating the good sensitivity and repeatability of the measurements. PMID:25658393

  15. Development of a moisture-in-solid-insulation sensor for power transformers.

    PubMed

    García, Belén; García, Diego; Robles, Guillermo

    2015-01-01

    Moisture is an important variable that must be kept under control to guarantee a safe operation of power transformers. Because of the hydrophilic character of cellulose, water mainly remains in the solid insulation, while just a few parts per million are dissolved in oil. The distribution of moisture between paper and oil is not static, but varies depending on the insulation temperature, and thus, water migration processes take place continuously during transformers operation. In this work, a sensor is presented that allows the determination of the moisture content of the transformer solid insulation in the steady state and during the moisture migration processes. The main objective of the design is that the electrodes of the sensor should not obstruct the movement of water from the solid insulation to the oil, so the proposed prototype uses a metallic-mesh electrode to do the measurements. The measurement setup is based on the characterization of the insulation dielectric response by means of the frequency dielectric spectroscopy (FDS) method. The sensitivity of the proposed sensor has been tested on samples with a moisture content within 1% to 5%, demonstrating the good sensitivity and repeatability of the measurements. PMID:25658393

  16. Evaluation of the capacitance-based low cost soil moisture sensor Decagon 10HS: Implications for soil moisture monitoring and related hydrological applications

    NASA Astrophysics Data System (ADS)

    Mittelbach, Heidi; Casini, Francesca; Lehner, Irene; Teuling, Ryan; Seneviratne, Sonia I.

    2010-05-01

    Soil moisture is an important component of the hydrological and climate system. It reflects precipitation and radiation anomalies, and directly impacts the partitioning of water and energy fluxes at the land surface. However observations of soil moisture and evapotranspiration, necessary to study land surface-atmosphere interactions, are scarce. Within the Swiss Soil Moisture EXperiment (SwissSMEX, http://www.iac.ethz.ch/url/research/SwissSMEX) an observational network of 13 stations for soil moisture measurements in Switzerland was established in 2008/09. Information about soil texture and vegetation is available at each station. Profile measurements of soil moisture down to 120 cm have been established. With a coverage down to 120 cm, not only the land surface-atmosphere interactions but also root water uptake and surface-subsurface interactions of soil moisture can be determined. Consequently, a better understanding and prediction of processes and their interactions in the land-atmosphere system is expected. To increase the on-site instrumentation and the density of the soil moisture network, a low cost sensor based on the capacitance technique was selected, beside reference measurements with the Time Domain Reflectometry (TDR) technique. These sensors are known to be less accurate but are significantly cheaper (factor 10) than the highly accurate TDR sensors. For this reason, several networks have been established using capacitance-based sensors to monitor soil moisture. For the SwissSMEX stations the low cost soil moisture sensor 10HS (Decagon Devices Inc., Pullman WA, USA) was installed at 6 levels from 5 cm down to 120 cm. The high accuracy TDR sensors TRIME-EZ and TRIME-IT (IMKO GmbH, Ettlingen, Germany) were installed in parallel to the 10HS sensor in two different depths at all sites, and over whole profiles at two sites. We present here the evaluation of the 10HS sensor in the framework of the SwissSMEX campaign, based on laboratory measurements as well

  17. Monitoring Moisture Content in Surface Barriers Using a Passive Sensor Platform

    SciTech Connect

    Kunerth, Dennis Clyde; Svoboda, John Mark; Lee, James Edwin

    2001-09-01

    Work is being performed to develop a versatile micro-power sensor platform for the purpose of periodic, remote sensing of environmental variables such as subsurface moisture or radiation. The key characteristics of the platform architecture are that the components are passive, thereby requiring no internal power source and that it communicates with a "reader" via short range telemetry, i.e. no wires need penetrate barrier structure. Other significant attributes include the potential for a long service life and a compact size that makes it well suited for retrofitting existing barrier structures. Functionally, the sensor package is read by a short range induction coil that both activates/powers the sensor platform and detects the sensor output via a radio frequency signal generated by the onboard programmable interface controller microchip. To date, a prototype of the platform has been constructed and tested with a commercial moisture sensor. Work is now in progress to extend the capabilities of the existing platform to permit moisture sensing through landfill surface barriers (caps). Specifically, work is being performed to extend the telemetry range for transmission through a cap, select/develop low power sensor elements, and package the components to survive subsurface conditions. Considerations are being given to minimize package dimensions to permit retrofit applications.

  18. High dielectric insulation coating for time domain reflectometry soil moisture sensor

    NASA Astrophysics Data System (ADS)

    Fujiyasu, Y.; Pierce, C. E.; Fan, L.; Wong, C. P.

    2004-04-01

    Insulation coating is often applied to time domain reflectometry (TDR) soil moisture sensors to reduce the conduction loss of energy. However, because of low dielectric constants of common plastic insulation materials, sensitivity is reduced, and the measurements are strongly dependent on coating thickness. Analytical studies clearly showed that these unwanted features could be mitigated if a high dielectric material is used for coating. An epoxy-ceramic nanocomposite was selected as a high dielectric insulation material because of its high dielectric constant and high adhesion. Experimental work using this composite indicated that the material has the potential to be used as a high dielectric coating for TDR soil moisture probes. On the basis of the results of these analytical and experimental studies a framework for designing an improved epoxy-ceramic composite for coating TDR soil moisture sensors is suggested.

  19. Integration of multiple satellite sensor resources for soil moisture and land surface temperature

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Satellite-based passive microwave sensors have been available for thirty years and provide the basis for both soil moisture and land surface temperature monitoring and mapping. Both of these variables are important in hydrologic and weather forecasts as well as climate analyses requiring longer peri...

  20. Use of Soil Moisture Sensors in Problem Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil dielectric sensors are based on the assumption that all soil water has the permittivity of free water (~76 to 80 depending on temperature and salt load) at all relevent frequencies (< 1.5 GHz); however, this assumption is not valid when there are appreciable amounts of water sorbed to high char...

  1. Temporal observations of surface soil moisture using a passive microwave sensor

    NASA Technical Reports Server (NTRS)

    Jackson, T. J.; O'Neill, P.

    1987-01-01

    A series of 10 aircraft flights was conducted over agricultural fields to evaluate relationships between observed surface soil moisture and soil moisture predicted using passive microwave sensor observations. An a priori approach was used to predict values of surface soil moisture for three types of fields: tilled corn, no-till corn with soybean stubble, and idle fields with corn stubble. Acceptable predictions were obtained for the tilled corn fields, while poor results were obtained for the others. The source of error is suspected to be the density and orientation of the surface stubble layer; however, further research is needed to verify this explanation. Temporal comparisons between observed, microwave predicted, and soil water-simulated moisture values showed similar patterns for tilled well-drained fields. Divergences between the observed and simulated measurements were apparent on poorly drained fields. This result may be of value in locating and mapping hydrologic contributing areas.

  2. Low-Cost Soil Moisture Profile Probe Using Thin-Film Capacitors and a Capacitive Touch Sensor.

    PubMed

    Kojima, Yuki; Shigeta, Ryo; Miyamoto, Naoya; Shirahama, Yasutomo; Nishioka, Kazuhiro; Mizoguchi, Masaru; Kawahara, Yoshihiro

    2016-01-01

    Soil moisture is an important property for agriculture, but currently commercialized soil moisture sensors are too expensive for many farmers. The objective of this study is to develop a low-cost soil moisture sensor using capacitors on a film substrate and a capacitive touch integrated circuit. The performance of the sensor was evaluated in two field experiments: a grape field and a mizuna greenhouse field. The developed sensor captured dynamic changes in soil moisture at 10, 20, and 30 cm depth, with a period of 10-14 days required after sensor installation for the contact between capacitors and soil to settle down. The measured soil moisture showed the influence of individual sensor differences, and the influence masked minor differences of less than 0.05 m³·m(-3) in the soil moisture at different locations. However, the developed sensor could detect large differences of more than 0.05 m³·m(-3), as well as the different magnitude of changes, in soil moisture. The price of the developed sensor was reduced to 300 U.S. dollars and can be reduced even more by further improvements suggested in this study and by mass production. Therefore, the developed sensor will be made more affordable to farmers as it requires low financial investment, and it can be utilized for decision-making in irrigation. PMID:27537881

  3. Calibrating a FDR sensor for soil moisture monitoring in a wetland in Central Kenya

    NASA Astrophysics Data System (ADS)

    Böhme, Beate; Becker, Mathias; Diekkrüger, Bernd

    The recent transformation of wetlands into farmland in East Africa is accelerating due to growing food-demand, land shortages, and an increasing unpredictability of climatic conditions for crop production in uplands. However, the conversion of pristine wetlands into sites of production may alter hydrological attributes with negative effects on production potential. Particularly the amount and the dynamics of plant available soil moisture in the rooting zone of crops determine to a large extent the agricultural production potential of wetlands. Various methods exist to assess soil moisture dynamics with Frequency Domain Reflectometry (FDR) being among the most prominent. However, the suitability of FDR sensors for assessing plant available soil moisture has to date not been confirmed for wetland soils in the region. We monitored the seasonal and spatial dynamics of water availability for crop growth in an inland valley wetland of the Kenyan highlands using a FDR sensor which was site-specifically calibrated. Access tubes were installed within different wetland use types and hydrological situations along valley transects and soil properties affecting soil moisture (organic C, texture, and bulk density) were investigated. There was little variation in soil attributes between physical positions in the valley, and also between topsoil and subsoil attributes with the exception of organic C contents. With a root mean squared error of 0.073 m3/m3, the developed calibration function of the FDR sensor allows for reasonably accurate soil moisture prediction for both within-site comparisons and the monitoring of temporal soil moisture variations. Applying the calibration equation to a time series of profile probe readings over a period of one year illustrated not only the temporal variation of soil moisture, but also effects of land use.

  4. Comparison of four soil moisture sensor types under field conditions in Switzerland

    NASA Astrophysics Data System (ADS)

    Mittelbach, Heidi; Lehner, Irene; Seneviratne, Sonia I.

    2012-04-01

    SummaryMany environmental and hydrological applications require knowledge about soil moisture. Its measurement accuracy is known to depend on the sensor technique, which is sensitive to soil characteristics such as texture, temperature, bulk density and salinity. However, the calibration functions provided by instrument manufacturers are generally developed under laboratory conditions, and their accuracy for field applications is rarely investigated, in particular over long time periods and in comparison with other sensors types. In this paper, four side-by-side profile soil moisture measurements down to 110 cm using three low-cost sensors and one high-accuracy and high-cost time domain reflectometry (TDR) sensor are compared over a 2-year period at a clay loam site in Switzerland. The low-cost instruments include the (1) 10HS (Decagon Devices, United States), (2) CS616 (Campbell Scientific, United States), and (3) SISOMOP (SMG University of Karlsruhe, Germany) sensors, which are evaluated against the (4) TDR-based TRIME-IT/-EZ (IMKO GmbH, Germany) sensors. For the comparison, the calibration functions provided by the manufacturers are applied for each sensor type. The sensors are evaluated based on daily data regarding their representation of the volumetric water content (VWC) and its anomalies, as well as the respective temperature dependency of the measurements. Furthermore, for each sensor type the actual evapotranspiration is estimated using the soil water balance approach and compared with measurements from a weighing lysimeter. It is shown that the root mean square difference (RMSD) of VWC for the low-cost sensors compared to the TDR measurements are up to 0.3 m3/m3, with highest values in near-surface layers. However, the RMSD for the VWC anomalies are lower compared to those for absolute values. We conclude that under the studied conditions none of the evaluated low-cost sensors has a level of performance consistent with the respective manufacturer

  5. Optical Fiber Sensors for Advanced Civil Structures

    NASA Astrophysics Data System (ADS)

    de Vries, Marten Johannes Cornelius

    1995-01-01

    The objective of this dissertation is to develop, analyze, and implement optical fiber-based sensors for the nondestructive quantitative evaluation of advanced civil structures. Based on a comparative evaluation of optical fiber sensors that may be used to obtain quantitative information related to physical perturbations in the civil structure, the extrinsic Fabry-Perot interferometric (EFPI) optical fiber sensor is selected as the most attractive sensor. The operation of the EFPI sensor is explained using the Kirchhoff diffraction approach. As is shown in this dissertation, this approach better predicts the signal-to-noise ratio as a function of gap length than methods employed previously. The performance of the optical fiber sensor is demonstrated in three different implementations. In the first implementation, performed with researchers in the Civil Engineering Department at the University of Southern California in Los Angeles, optical fiber sensors were used to obtain quantitative strain information from reinforced concrete interior and exterior column-to-beam connections. The second implementation, performed in cooperation with researchers at the United States Bureau of Mines in Spokane, Washington, used optical fiber sensors to monitor the performance of roof bolts used in mines. The last implementation, performed in cooperation with researchers at the Turner-Fairbanks Federal Highway Administration Research Center in McLean, Virginia, used optical fiber sensors, attached to composite prestressing strands used for reinforcing concrete, to obtain absolute strain information. Multiplexing techniques including time, frequency and wavelength division multiplexing are briefly discussed, whereas the principles of operation of spread spectrum and optical time domain reflectometery (OTDR) are discussed in greater detail. Results demonstrating that spread spectrum and OTDR techniques can be used to multiplex optical fiber sensors are presented. Finally, practical

  6. Next Generation Advanced Video Guidance Sensor

    NASA Technical Reports Server (NTRS)

    Lee, Jimmy; Spencer, Susan; Bryan, Tom; Johnson, Jimmie; Robertson, Bryan

    2008-01-01

    The first autonomous rendezvous and docking in the history of the U.S. Space Program was successfully accomplished by Orbital Express, using the Advanced Video Guidance Sensor (AVGS) as the primary docking sensor. The United States now has a mature and flight proven sensor technology for supporting Crew Exploration Vehicles (CEV) and Commercial Orbital Transport. Systems (COTS) Automated Rendezvous and Docking (AR&D). AVGS has a proven pedigree, based on extensive ground testing and flight demonstrations. The AVGS on the Demonstration of Autonomous Rendezvous Technology (DART)mission operated successfully in "spot mode" out to 2 km. The first generation rendezvous and docking sensor, the Video Guidance Sensor (VGS), was developed and successfully flown on Space Shuttle flights in 1997 and 1998. Parts obsolescence issues prevent the construction of more AVGS. units, and the next generation sensor must be updated to support the CEV and COTS programs. The flight proven AR&D sensor is being redesigned to update parts and add additional. capabilities for CEV and COTS with the development of the Next, Generation AVGS (NGAVGS) at the Marshall Space Flight Center. The obsolete imager and processor are being replaced with new radiation tolerant parts. In addition, new capabilities might include greater sensor range, auto ranging, and real-time video output. This paper presents an approach to sensor hardware trades, use of highly integrated laser components, and addresses the needs of future vehicles that may rendezvous and dock with the International Space Station (ISS) and other Constellation vehicles. It will also discuss approaches for upgrading AVGS to address parts obsolescence, and concepts for minimizing the sensor footprint, weight, and power requirements. In addition, parts selection and test plans for the NGAVGS will be addressed to provide a highly reliable flight qualified sensor. Expanded capabilities through innovative use of existing capabilities will also be

  7. Soil moisture sensing via swept frequency based microwave sensors.

    PubMed

    Pelletier, Mathew G; Karthikeyan, Sundar; Green, Timothy R; Schwartz, Robert C; Wanjura, John D; Holt, Greg A

    2012-01-01

    There is a need for low-cost, high-accuracy measurement of water content in various materials. This study assesses the performance of a new microwave swept frequency domain instrument (SFI) that has promise to provide a low-cost, high-accuracy alternative to the traditional and more expensive time domain reflectometry (TDR). The technique obtains permittivity measurements of soils in the frequency domain utilizing a through transmission configuration, transmissometry, which provides a frequency domain transmissometry measurement (FDT). The measurement is comparable to time domain transmissometry (TDT) with the added advantage of also being able to separately quantify the real and imaginary portions of the complex permittivity so that the measured bulk permittivity is more accurate that the measurement TDR provides where the apparent permittivity is impacted by the signal loss, which can be significant in heavier soils. The experimental SFI was compared with a high-end 12 GHz TDR/TDT system across a range of soils at varying soil water contents and densities. As propagation delay is the fundamental measurement of interest to the well-established TDR or TDT technique; the first set of tests utilized precision propagation delay lines to test the accuracy of the SFI instrument's ability to resolve propagation delays across the expected range of delays that a soil probe would present when subjected to the expected range of soil types and soil moisture typical to an agronomic cropping system. The results of the precision-delay line testing suggests the instrument is capable of predicting propagation delays with a RMSE of +/-105 ps across the range of delays ranging from 0 to 12,000 ps with a coefficient of determination of r(2) = 0.998. The second phase of tests noted the rich history of TDR for prediction of soil moisture and leveraged this history by utilizing TDT measured with a high-end Hewlett Packard TDR/TDT instrument to directly benchmark the SFI instrument over

  8. Advances in miniature spectrometer and sensor development

    NASA Astrophysics Data System (ADS)

    Malinen, Jouko; Rissanen, Anna; Saari, Heikki; Karioja, Pentti; Karppinen, Mikko; Aalto, Timo; Tukkiniemi, Kari

    2014-05-01

    Miniaturization and cost reduction of spectrometer and sensor technologies has great potential to open up new applications areas and business opportunities for analytical technology in hand held, mobile and on-line applications. Advances in microfabrication have resulted in high-performance MEMS and MOEMS devices for spectrometer applications. Many other enabling technologies are useful for miniature analytical solutions, such as silicon photonics, nanoimprint lithography (NIL), system-on-chip, system-on-package techniques for integration of electronics and photonics, 3D printing, powerful embedded computing platforms, networked solutions as well as advances in chemometrics modeling. This paper will summarize recent work on spectrometer and sensor miniaturization at VTT Technical Research Centre of Finland. Fabry-Perot interferometer (FPI) tunable filter technology has been developed in two technical versions: Piezoactuated FPIs have been applied in miniature hyperspectral imaging needs in light weight UAV and nanosatellite applications, chemical imaging as well as medical applications. Microfabricated MOEMS FPIs have been developed as cost-effective sensor platforms for visible, NIR and IR applications. Further examples of sensor miniaturization will be discussed, including system-on-package sensor head for mid-IR gas analyzer, roll-to-roll printed Surface Enhanced Raman Scattering (SERS) technology as well as UV imprinted waveguide sensor for formaldehyde detection.

  9. Field Calibrations of Soil Moisture Sensors in a Forested Watershed

    PubMed Central

    Abbas, Farhat; Fares, Ali; Fares, Samira

    2011-01-01

    Spatially variable soil properties influence the performance of soil water content monitoring sensors. The objectives of this research were to: (i) study the spatial variability of bulk density (ρb), total porosity (θt), clay content (CC), electrical conductivity (EC), and pH in the upper Mākaha Valley watershed soils; (ii) explore the effect of variations in ρb and θt on soil water content dynamics, and (iii) establish field calibration equations for EC-20 (Decagon Devices, Inc), ML2x (Delta-T-Devices), and SM200 (Delta-T-Devices) sensors to mitigate the effect of soil spatial variability on their performance. The studied soil properties except pH varied significantly (P < 0.05) across the soil water content monitoring depths (20 and 80 cm) and six locations. There was a linear positive and a linear inverse correlation between the soil water content at sampling and ρb, and between the soil water content at sampling and θt, respectively. Values of laboratory measured actual θt correlated (r = 0.75) with those estimated from the relationship θt = 1 − ρb/ρs, where ρs is the particle density. Variations in the studied soil properties affected the performance of the default equations of the three tested sensors; they showed substantial under-estimations of the actual water content. The individual and the watershed-scale field calibrations were more accurate than their corresponding default calibrations. In conclusion, the sensors used in this study need site-specific calibrations in order to mitigate the effects of varying properties of the highly weathered tropical soils. PMID:22163959

  10. Sensors for measurement of moisture diffusion in power cables with oil-impregnated paper

    NASA Astrophysics Data System (ADS)

    Thomas, Z. M.; Zahn, M.; Yang, W.

    2007-07-01

    Some old power cables use oil-impregnated paper as the insulation material, which is enclosed by a layer of lead sheath. As cracks can form on the sheath of aged cables, the oil-impregnated paper can be exposed to the environmental conditions, and ambient moisture can diffuse into the paper through the cracks, causing a reduced breakdown voltage. To understand this diffusion phenomenon, multi-wavelength dielectrometry sensors have been used to measure permittivity and conductivity, aiming to obtain information on the moisture content. Different electrode-grouping strategies have been suggested to obtain more detailed information. Effectively, an electrode-grouping approach forms a type of electrical capacitance tomography sensor. This paper presents different sensor designs together with a capacitance measuring circuit. Some analytical results are also presented.

  11. Wireless sensor network deployment for monitoring soil moisture dynamics at the field scale

    NASA Astrophysics Data System (ADS)

    Majone, B.; Bellin, A.; Filippi, E.; Ioriatti, L.; Martinelli, M.; Massa, A.; Toller, G.

    2009-12-01

    We describe a recent deployment of soil moisture and temperature sensors in an apple tree orchard aimed at exploring the interaction between soil moisture dynamics and plant physiology. The field is divided into three parcels with different constant irrigation rates. The deployment includes dendrometers which monitor the variations of the trunk diameter. The idea is to monitor continuously and at small time steps soil moisture dynamics, soil temperature and a parameter reflecting plant stress at the parcel scale, in order to better investigate the interaction between plant physiology and soil moisture dynamics. Other sensors monitoring plant physiology can be easily accommodated within the Wireless Sensor Network (WSN). The experimental site is an apple orchard of 5000 m2 located at Cles, province of Trento, Italy, at the elevation of 640 m.a.s.l. In this site about 1200 apple trees are cultivated (cultivar Golden Delicious). The trees have been planted in 2004 in north-south rows 3.5 m apart. The deployment consists of 27 locations connected by a multi hop WSN, each one equipped with 5 soil moisture sensors (capacitance sensors EC-5, decagon Service) at the depths of 10, 20, 30, 50 and 80 cm, and a temperature sensor at the depth of 20 cm, for a total of 135 soil moisture and 27 temperature sensors. The proposed monitoring system is based on totally autonomous sensor nodes which allow both real time and historic data management. The data gathered are then organized in a database on a public web site. The node sensors are connected through an input/output interface to a WSN platform. The power supply consists of a solar panel able to provide 250 mA at 7 V and a 3V DC/DC converter based on a dual frequency high efficient switching regulator. The typical meteorological data are monitored with a weather station located at a distance of approximately 100 m from the experimental site. Great care has been posed to calibration of the capacitance sensors both in the

  12. Advanced uncooled sensor product development

    NASA Astrophysics Data System (ADS)

    Kennedy, A.; Masini, P.; Lamb, M.; Hamers, J.; Kocian, T.; Gordon, E.; Parrish, W.; Williams, R.; LeBeau, T.

    2015-06-01

    The partnership between RVS, Seek Thermal and Freescale Semiconductor continues on the path to bring the latest technology and innovation to both military and commercial customers. The partnership has matured the 17μm pixel for volume production on the Thermal Weapon Sight (TWS) program in efforts to bring advanced production capability to produce a low cost, high performance product. The partnership has developed the 12μm pixel and has demonstrated performance across a family of detector sizes ranging from formats as small as 206 x 156 to full high definition formats. Detector pixel sensitivities have been achieved using the RVS double level advanced pixel structure. Transition of the packaging of microbolometers from a traditional die level package to a wafer level package (WLP) in a high volume commercial environment is complete. Innovations in wafer fabrication techniques have been incorporated into this product line to assist in the high yield required for volume production. The WLP seal yield is currently > 95%. Simulated package vacuum lives >> 20 years have been demonstrated through accelerated life testing where the package has been shown to have no degradation after 2,500 hours at 150°C. Additionally the rugged assembly has shown no degradation after mechanical shock and vibration and thermal shock testing. The transition to production effort was successfully completed in 2014 and the WLP design has been integrated into multiple new production products including the TWS and the innovative Seek Thermal commercial product that interfaces directly to an iPhone or android device.

  13. Description and testing of three moisture sensors for measuring surface wetness on carbonate building stones

    USGS Publications Warehouse

    See, R.B.; Reddy, M.M.; Martin, R.G.

    1987-01-01

    Three sensors were tested on building stones exposed to conditions that produce deposition of moisture. A relative humidity probe, a gypsum collected circuit grid, and a limestone block resistor were tested as sensors for determining surface wetness. Sensors were tested under laboratory conditions of constant relative humidity and temperature and also under on-site conditions of variable relative humidity and temperature for 8 weeks at Newcomb, New York. Laboratory tests indicated that relative humidity alone did not cause sensors to become saturated. However, relative humidity did control the rate at which sensors dried after being saturated with distilled water. On-site testing of the relative humidity probe and the gypsum coated circuit grid indicated that they respond to a diurnal wetting and drying cycle; the limestone block resistor only responded to rainfall. (Author 's abstract)

  14. Advanced Video Guidance Sensor and Next Generation Autonomous Docking Sensors

    NASA Technical Reports Server (NTRS)

    Granade, Stephen R.

    2004-01-01

    In recent decades, NASA's interest in spacecraft rendezvous and proximity operations has grown. Additional instrumentation is needed to improve manned docking operations' safety, as well as to enable telerobotic operation of spacecraft or completely autonomous rendezvous and docking. To address this need, Advanced Optical Systems, Inc., Orbital Sciences Corporation, and Marshall Space Flight Center have developed the Advanced Video Guidance Sensor (AVGS) under the auspices of the Demonstration of Autonomous Rendezvous Technology (DART) program. Given a cooperative target comprising several retro-reflectors, AVGS provides six-degree-of-freedom information at ranges of up to 300 meters for the DART target. It does so by imaging the target, then performing pattern recognition on the resulting image. Longer range operation is possible through different target geometries. Now that AVGS is being readied for its test flight in 2004, the question is: what next? Modifications can be made to AVGS, including different pattern recognition algorithms and changes to the retro-reflector targets, to make it more robust and accurate. AVGS could be coupled with other space-qualified sensors, such as a laser range-and-bearing finder, that would operate at longer ranges. Different target configurations, including the use of active targets, could result in significant miniaturization over the current AVGS package. We will discuss these and other possibilities for a next-generation docking sensor or sensor suite that involve AVGS.

  15. Remote Sensing of Soil Moisture based on Dynamic Vegetation Scattering Properties for AMSR sensors

    NASA Astrophysics Data System (ADS)

    Du, J.; Kimball, J. S.; Jones, L. A.

    2015-12-01

    Accurate mapping of soil moisture and its spatial-temporal variations are of great significance to scientific studies on global water, energy and carbon cycles as well as operational applications including flood and drought monitoring, water resources management and crop yield forecasts. An approach for deriving volumetric soil moisture using satellite passive microwave radiometry from the Advanced Microwave Scanning Radiometers AMSR-E and AMSR2 was developed in this study. The algorithm adopts a weighted averaging strategy for soil moisture estimation based on a dynamic selection of empirically determined vegetation single-scatter albedo values. The resulting soil moisture retrievals demonstrate more realistic global patterns and seasonal dynamics relative to the baseline University of Montana (UMT) soil moisture product. Quantitative analysis of the new approach against in situ soil moisture measurements over four global study regions also indicates significant improvement over the baseline algorithm, with coefficients of determination (R2) between the retrievals and in-situ measurements increasing by approximately 16.9% and 41.5% respectively; and bias-corrected RMSEs decreasing by about 25.0% and 38.2% for respective ascending and descending orbital data records. Initial comparisons between soil moisture retrievals from AMSR2 and SMAP indicate coherent global and seasonal patterns.

  16. Development of advanced magnetic resonance sensor for industrial applications. Final report

    SciTech Connect

    De Los Santos, A.

    1997-06-01

    Southwest Research Institute (SwRI) and various subcontractors, in a cooperative agreement with the DOE, have developed and tested an advanced magnetic resonance (MR) sensor for several industrial applications and made various market surveys. The original goal of the program was to develop an advanced moisture sensor to allow more precise and rapid control of drying processes so that energy and/or product would not be wasted. Over the course of the program, it was shown that energy savings were achievable but in many processes the return in investment did not justify the cost of a magnetic resonance sensor. However, in many processes, particularly chemical, petrochemical, paper and others, the return in investment can be very high as to easily justify the cost of a magnetic resonance sensor. In these industries, substantial improvements in product yield, quality, and efficiency in production can cause substantial energy savings and reductions in product wastage with substantial environmental effects. The initial applications selected for this program included measurement of corn gluten at three different points and corn germ at one point in an American Maize corn processing plant. During the initial phases (I and II) of this program, SwRI developed a prototype advanced moisture sensor utilizing NMR technology capable of accurately and reliably measuring moisture in industrial applications and tested the sensor in the laboratory under conditions simulating on-line products in the corn wet milling industry. The objective of Phase III was to test the prototype sensor in the plant environment to determine robustness, reliability and long term stability. Meeting these objectives would permit extended field testing to improve the statistical database used to calibrate the sensor and subject the sensor to true variations in operating conditions encountered in the process rather than those which could only be simulated in the laboratory.

  17. Validation of Distributed Soil Moisture: Airborne Polarimetric SAR vs. Ground-based Sensor Networks

    NASA Astrophysics Data System (ADS)

    Jagdhuber, T.; Kohling, M.; Hajnsek, I.; Montzka, C.; Papathanassiou, K. P.

    2012-04-01

    The knowledge of spatially distributed soil moisture is highly desirable for an enhanced hydrological modeling in terms of flood prevention and for yield optimization in combination with precision farming. Especially in mid-latitudes, the growing agricultural vegetation results in an increasing soil coverage along the crop cycle. For a remote sensing approach, this vegetation influence has to be separated from the soil contribution within the resolution cell to extract the actual soil moisture. Therefore a hybrid decomposition was developed for estimation of soil moisture under vegetation cover using fully polarimetric SAR data. The novel polarimetric decomposition combines a model-based decomposition, separating the volume component from the ground components, with an eigen-based decomposition of the two ground components into a surface and a dihedral scattering contribution. Hence, this hybrid decomposition, which is based on [1,2], establishes an innovative way to retrieve soil moisture under vegetation. The developed inversion algorithm for soil moisture under vegetation cover is applied on fully polarimetric data of the TERENO campaign, conducted in May and June 2011 for the Rur catchment within the Eifel/Lower Rhine Valley Observatory. The fully polarimetric SAR data were acquired in high spatial resolution (range: 1.92m, azimuth: 0.6m) by DLR's novel F-SAR sensor at L-band. The inverted soil moisture product from the airborne SAR data is validated with corresponding distributed ground measurements for a quality assessment of the developed algorithm. The in situ measurements were obtained on the one hand by mobile FDR probes from agricultural fields near the towns of Merzenhausen and Selhausen incorporating different crop types and on the other hand by distributed wireless sensor networks (SoilNet clusters) from a grassland test site (near the town of Rollesbroich) and from a forest stand (within the Wüstebach sub-catchment). Each SoilNet cluster

  18. Advanced sensors, technology lower costs, boost productivity

    SciTech Connect

    Altpeter, L.L.; Kothari, K.

    1997-04-01

    Lower costs and higher productivity for the maintenance and repair of gas distribution systems has become an ever-increasing challenge to local distribution companies throughout the United States. A significant portion of costs for operations such as pipe location, leak pinpointing and leak surveying, arise from the inadequacies of their sensing technologies, some of which have not changed significantly in nearly 30 years. After reviewing the basic costs of pipe location, leak pinpointing, and leak surveying operations, the paper describes several advanced sensors for gas leak detection, and several sensors for pipe location and leak pinpointing.

  19. Advanced Video Guidance Sensor (AVGS) Development Testing

    NASA Technical Reports Server (NTRS)

    Howard, Richard T.; Johnston, Albert S.; Bryan, Thomas C.; Book, Michael L.

    2004-01-01

    NASA's Marshall Space Flight Center was the driving force behind the development of the Advanced Video Guidance Sensor, an active sensor system that provides near-range sensor data as part of an automatic rendezvous and docking system. The sensor determines the relative positions and attitudes between the active sensor and the passive target at ranges up to 300 meters. The AVGS uses laser diodes to illuminate retro-reflectors in the target, a solid-state camera to detect the return from the target, and image capture electronics and a digital signal processor to convert the video information into the relative positions and attitudes. The AVGS will fly as part of the Demonstration of Autonomous Rendezvous Technologies (DART) in October, 2004. This development effort has required a great deal of testing of various sorts at every phase of development. Some of the test efforts included optical characterization of performance with the intended target, thermal vacuum testing, performance tests in long range vacuum facilities, EMI/EMC tests, and performance testing in dynamic situations. The sensor has been shown to track a target at ranges of up to 300 meters, both in vacuum and ambient conditions, to survive and operate during the thermal vacuum cycling specific to the DART mission, to handle EM1 well, and to perform well in dynamic situations.

  20. Advanced microwave soil moisture studies. [Big Sioux River Basin, Iowa

    NASA Technical Reports Server (NTRS)

    Dalsted, K. J.; Harlan, J. C.

    1983-01-01

    Comparisons of low level L-band brightness temperature (TB) and thermal infrared (TIR) data as well as the following data sets: soil map and land cover data; direct soil moisture measurement; and a computer generated contour map were statistically evaluated using regression analysis and linear discriminant analysis. Regression analysis of footprint data shows that statistical groupings of ground variables (soil features and land cover) hold promise for qualitative assessment of soil moisture and for reducing variance within the sampling space. Dry conditions appear to be more conductive to producing meaningful statistics than wet conditions. Regression analysis using field averaged TB and TIR data did not approach the higher sq R values obtained using within-field variations. The linear discriminant analysis indicates some capacity to distinguish categories with the results being somewhat better on a field basis than a footprint basis.

  1. A microwave microstrip ring resonator as a moisture sensor for biomaterials: application to wheat grains

    NASA Astrophysics Data System (ADS)

    Abegaonkar, Mahesh P.; Karekar, R. N.; Aiyer, R. C.

    1999-03-01

    A miniaturized, non-destructive sensor employing a microwave microstrip ring resonator (MRR, 0957-0233/10/3/014/img1 GHz, mean diameter 3.69 mm) was developed for estimating the moisture content of a single wheat ( Triticum aestivum L) grain. A single wheat grain with a known amount of moisture was placed on the MRR at two different orientations (0957-0233/10/3/014/img2 and 0957-0233/10/3/014/img3) with respect to the feedline. The resonance frequency 0957-0233/10/3/014/img4, bandwidth (B) and quality factor 0957-0233/10/3/014/img5 of the MRR were calibrated against the moisture content. The measurements were made with a scalar network analyser. The sensor was studied in the normal useful moisture range of 11-32% (on a wet-weight basis), the actual moisture values being obtained by an oven-drying method. The 0957-0233/10/3/014/img2 orientation was more sensitive to moisture than was the 0957-0233/10/3/014/img3 orientation. The total changes in 0957-0233/10/3/014/img8 for a 21% change in moisture content for 0957-0233/10/3/014/img2 and 900957-0233/10/3/014/img10 orientations were 235 and 150 MHz, respectively. The errors in moisture estimation with 0957-0233/10/3/014/img8 for 0957-0233/10/3/014/img2 and 0957-0233/10/3/014/img3 were 0957-0233/10/3/014/img14% and 0957-0233/10/3/014/img15%, respectively. The corresponding values with B and 0957-0233/10/3/014/img16 for 0957-0233/10/3/014/img3 orientation were 0957-0233/10/3/014/img18% and 0957-0233/10/3/014/img19%, respectively. The proposed sensor is more sensitive than a reported waveguide resonator and is easy to operate, for the microstrip offers an open structure, thereby facilitating easy loading and unloading of the samples.

  2. Advanced Soil Moisture Network Technologies; Developments in Collecting in situ Measurements for Remote Sensing Missions

    NASA Astrophysics Data System (ADS)

    Moghaddam, M.; Silva, A. R. D.; Akbar, R.; Clewley, D.

    2015-12-01

    The Soil moisture Sensing Controller And oPtimal Estimator (SoilSCAPE) wireless sensor network has been developed to support Calibration and Validation activities (Cal/Val) for large scale soil moisture remote sensing missions (SMAP and AirMOSS). The technology developed here also readily supports small scale hydrological studies by providing sub-kilometer widespread soil moisture observations. An extensive collection of semi-sparse sensor clusters deployed throughout north-central California and southern Arizona provide near real time soil moisture measurements. Such a wireless network architecture, compared to conventional single points measurement profiles, allows for significant and expanded soil moisture sampling. The work presented here aims at discussing and highlighting novel and new technology developments which increase in situ soil moisture measurements' accuracy, reliability, and robustness with reduced data delivery latency. High efficiency and low maintenance custom hardware have been developed and in-field performance has been demonstrated for a period of three years. The SoilSCAPE technology incorporates (a) intelligent sensing to prevent erroneous measurement reporting, (b) on-board short term memory for data redundancy, (c) adaptive scheduling and sampling capabilities to enhance energy efficiency. A rapid streamlined data delivery architecture openly provides distribution of in situ measurements to SMAP and AirMOSS cal/val activities and other interested parties.

  3. Distributed Sensor Coordination for Advanced Energy Systems

    SciTech Connect

    Tumer, Kagan

    2013-07-31

    The ability to collect key system level information is critical to the safe, efficient and reli- able operation of advanced energy systems. With recent advances in sensor development, it is now possible to push some level of decision making directly to computationally sophisticated sensors, rather than wait for data to arrive to a massive centralized location before a decision is made. This type of approach relies on networked sensors (called “agents” from here on) to actively collect and process data, and provide key control deci- sions to significantly improve both the quality/relevance of the collected data and the as- sociating decision making. The technological bottlenecks for such sensor networks stem from a lack of mathematics and algorithms to manage the systems, rather than difficulties associated with building and deploying them. Indeed, traditional sensor coordination strategies do not provide adequate solutions for this problem. Passive data collection methods (e.g., large sensor webs) can scale to large systems, but are generally not suited to highly dynamic environments, such as ad- vanced energy systems, where crucial decisions may need to be reached quickly and lo- cally. Approaches based on local decisions on the other hand cannot guarantee that each agent performing its task (maximize an agent objective) will lead to good network wide solution (maximize a network objective) without invoking cumbersome coordination rou- tines. There is currently a lack of algorithms that will enable self-organization and blend the efficiency of local decision making with the system level guarantees of global decision making, particularly when the systems operate in dynamic and stochastic environments. In this work we addressed this critical gap and provided a comprehensive solution to the problem of sensor coordination to ensure the safe, reliable, and robust operation of advanced energy systems. The differentiating aspect of the proposed work is in shift- ing

  4. Soil moisture spatial and temporal patterns from a wireless sensor network test bed

    NASA Astrophysics Data System (ADS)

    Villalba, G.; Davis, T. W.; Liang, X.

    2014-12-01

    The dynamics of water movement through vegetated porous media is a complex problem with large variabilities over differing temporal and spatial scales. This study examines a multi-year wireless sensor network (WSN) collecting shallow subsurface (10 and 30 cm) soil moisture content and soil water potential. The study site, located at the Audubon Society of Western Pennsylvania's Beechwood Farms Nature Reserve, is one of the longest running WSNs of its kind. Despite the noisy nature of the collected data (e.g., in comparison to traditional data logger methods), the WSN, consisting of over 50 nodes with more than 100 sensors, provides critical information regarding catchment-scale spatiotemporal patterns of soil moisture and soil water potential within a forested hill-sloped region of southwestern Pennsylvania.

  5. A methodology to identify representative configurations of sensors for monitoring soil moisture.

    PubMed

    Rivera, Diego; Granda, Stalin; Arumí, José Luis; Sandoval, Marco; Billib, Max

    2012-11-01

    Soil moisture is the key link among hydroecological compartments, responding dynamically to sequences of atmospheric processes and management conditions and modulating physical, chemical, and biological processes in the soil. Currently, there are a variety of monitoring techniques to measure, directly or indirectly, the soil moisture. However, some practical issues remain open like the definition a priori of the number, location and depth of the monitoring points, and the impact of failing or poor performance soil moisture sensors. Here, we present a set of techniques, namely Δθ time series, wavelet filtering, and time stability, to identify representative points and monitoring depths through an analysis of hourly soil moisture time series for different configuration of the monitoring network. We used real data from a monitoring network consisting of seven monitoring points, each one with four EC-5 probes (Decagon Devices Inc., Pullman, WA) at 20, 40, 60, and 100 cm. The use of simple time series of Δθ allowed us to assess the spatiotemporal influence of the monitoring points, while the wavelet periodograms allowed us to get insight about the response of the monitoring points at different time scales. Both methods are easy to implement or adapt to specific conditions, being coherent to the results derived from time stability analysis. For our case study, we concluded that we could reallocate 16 sensors (out of 28) without a significant loss of information. However, the final decision strongly relies on a deep knowledge of the site features and the objectives of the monitoring network. PMID:22146817

  6. Temporal Stability of Soil Moisture and Radar Backscatter Observed by the Advanced Synthetic Aperture Radar (ASAR)

    PubMed Central

    Wagner, Wolfgang; Pathe, Carsten; Doubkova, Marcela; Sabel, Daniel; Bartsch, Annett; Hasenauer, Stefan; Blöschl, Günter; Scipal, Klaus; Martínez-Fernández, José; Löw, Alexander

    2008-01-01

    The high spatio-temporal variability of soil moisture is the result of atmospheric forcing and redistribution processes related to terrain, soil, and vegetation characteristics. Despite this high variability, many field studies have shown that in the temporal domain soil moisture measured at specific locations is correlated to the mean soil moisture content over an area. Since the measurements taken by Synthetic Aperture Radar (SAR) instruments are very sensitive to soil moisture it is hypothesized that the temporally stable soil moisture patterns are reflected in the radar backscatter measurements. To verify this hypothesis 73 Wide Swath (WS) images have been acquired by the ENVISAT Advanced Synthetic Aperture Radar (ASAR) over the REMEDHUS soil moisture network located in the Duero basin, Spain. It is found that a time-invariant linear relationship is well suited for relating local scale (pixel) and regional scale (50 km) backscatter. The observed linear model coefficients can be estimated by considering the scattering properties of the terrain and vegetation and the soil moisture scaling properties. For both linear model coefficients, the relative error between observed and modelled values is less than 5 % and the coefficient of determination (R2) is 86 %. The results are of relevance for interpreting and downscaling coarse resolution soil moisture data retrieved from active (METOP ASCAT) and passive (SMOS, AMSR-E) instruments.

  7. The Soil Moisture Active Passive Marena Oklahoma In Situ Sensor Testbed (SMAP-MOISST): Design and initial results

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In situ soil moisture monitoring networks are critical to the development of soil moisture remote sensing missions as well as agricultural and environmental management, weather forecasting and many other endeavors. These in situ networks are composed of a variety of sensors and installation practic...

  8. Recent advances in integrated photonic sensors.

    PubMed

    Passaro, Vittorio M N; de Tullio, Corrado; Troia, Benedetto; La Notte, Mario; Giannoccaro, Giovanni; De Leonardis, Francesco

    2012-01-01

    Nowadays, optical devices and circuits are becoming fundamental components in several application fields such as medicine, biotechnology, automotive, aerospace, food quality control, chemistry, to name a few. In this context, we propose a complete review on integrated photonic sensors, with specific attention to materials, technologies, architectures and optical sensing principles. To this aim, sensing principles commonly used in optical detection are presented, focusing on sensor performance features such as sensitivity, selectivity and rangeability. Since photonic sensors provide substantial benefits regarding compatibility with CMOS technology and integration on chips characterized by micrometric footprints, design and optimization strategies of photonic devices are widely discussed for sensing applications. In addition, several numerical methods employed in photonic circuits and devices, simulations and design are presented, focusing on their advantages and drawbacks. Finally, recent developments in the field of photonic sensing are reviewed, considering advanced photonic sensor architectures based on linear and non-linear optical effects and to be employed in chemical/biochemical sensing, angular velocity and electric field detection. PMID:23202223

  9. Recent Advances in Integrated Photonic Sensors

    PubMed Central

    Passaro, Vittorio M. N.; de Tullio, Corrado; Troia, Benedetto; La Notte, Mario; Giannoccaro, Giovanni; De Leonardis, Francesco

    2012-01-01

    Nowadays, optical devices and circuits are becoming fundamental components in several application fields such as medicine, biotechnology, automotive, aerospace, food quality control, chemistry, to name a few. In this context, we propose a complete review on integrated photonic sensors, with specific attention to materials, technologies, architectures and optical sensing principles. To this aim, sensing principles commonly used in optical detection are presented, focusing on sensor performance features such as sensitivity, selectivity and rangeability. Since photonic sensors provide substantial benefits regarding compatibility with CMOS technology and integration on chips characterized by micrometric footprints, design and optimization strategies of photonic devices are widely discussed for sensing applications. In addition, several numerical methods employed in photonic circuits and devices, simulations and design are presented, focusing on their advantages and drawbacks. Finally, recent developments in the field of photonic sensing are reviewed, considering advanced photonic sensor architectures based on linear and non-linear optical effects and to be employed in chemical/biochemical sensing, angular velocity and electric field detection. PMID:23202223

  10. Development of advanced high-temperature heat flux sensors

    NASA Technical Reports Server (NTRS)

    Atkinson, W. H.; Strange, R. R.

    1982-01-01

    Various configurations of high temperature, heat flux sensors were studied to determine their suitability for use in experimental combustor liners of advanced aircraft gas turbine engines. It was determined that embedded thermocouple sensors, laminated sensors, and Gardon gauge sensors, were the most viable candidates. Sensors of all three types were fabricated, calibrated, and endurance tested. All three types of sensors met the fabricability survivability, and accuracy requirements established for their application.

  11. A Multi-Sensor Approach for Satellite Soil Moisture Monitoring for Agricultural Climate Risk Assessment

    NASA Astrophysics Data System (ADS)

    Champagne, C.; Cherneski, P.; Hadwen, T. A.; Davidson, A.

    2014-12-01

    Satellite missions specifically dedicated to soil moisture retrieval have become a reality in the past few years, with the launch of SMOS in 2009 and SMAP in 2014. While much of the work on applications around these missions has focussed on data assimilation systems for numerical weather prediction, there is also potential to use the data to support agricultural applications such as drought and flood assessment and yield forecasting. Previous work has examined the potential for using SMOS soil moisture for detecting spatial and temporal patterns of agroclimate risk, such as drought and excess wetness. This research builds upon that work through the examination of a data set with a longer reference period to determine if the dataset can be used as a baseline for detecting anomalies from normal conditions. Surface satellite soil moisture from a multi-sensor climate reference data set (1993 to 2010) and the SMOS surface soil moisture data (2010 - 2014) set were examined in hindsight to detect relevant trends for monitoring the climate conditions in agricultural regions of Canada. Soil moisture and soil moisture anomalies were examined against precipitation and temperature records over the relevant time periods, and compared against agroclimatic drought risk indicators, including the Palmer Drought Severity Index, the Standardized Precipitation Index and the MODIS Normalized Difference Vegetation Condition anomalies. High impact events, including the 2002 drought in the Canadian Prairies, excess wetness in the southern Manitoba in 2009 and 2011 were evaluated in detail. The potential for using these data sets in near real time to support agricultural decision making will be discussed.

  12. New dielectric sensors and sensing techniques for soil and snow moisture measurements.

    PubMed

    Stacheder, Markus; Koeniger, Franz; Schuhmann, Rainer

    2009-01-01

    Measurements of material moisture are essential in fields such as agriculture or civil engineering. Electromagnetic techniques, more precisely dielectric methods, have gained wide acceptance in the last decades. Frequency or Time Domain methods take advantage of the high dielectric permittivity of water compared to dry materials. This paper presents four new dielectric sensors for the determination of soil or snow water content. After a short introduction into the principles, both the hardware and operating mode of each sensor are described. Field test results show the advantages and potentials such as automatic measurement and profiling, state-of-ground detection or large-scale determination. From the results it follows that the presented sensors offer promising new tools for modern environmental research. PMID:22574056

  13. New Dielectric Sensors and Sensing Techniques for Soil and Snow Moisture Measurements

    PubMed Central

    Stacheder, Markus; Koeniger, Franz; Schuhmann, Rainer

    2009-01-01

    Measurements of material moisture are essential in fields such as agriculture or civil engineering. Electromagnetic techniques, more precisely dielectric methods, have gained wide acceptance in the last decades. Frequency or Time Domain methods take advantage of the high dielectric permittivity of water compared to dry materials. This paper presents four new dielectric sensors for the determination of soil or snow water content. After a short introduction into the principles, both the hardware and operating mode of each sensor are described. Field test results show the advantages and potentials such as automatic measurement and profiling, state-of-ground detection or large-scale determination. From the results it follows that the presented sensors offer promising new tools for modern environmental research. PMID:22574056

  14. Advances in Assimilation of Satellite-Based Passive Microwave Observations for Soil-Moisture Estimation

    NASA Technical Reports Server (NTRS)

    De Lannoy, Gabrielle J. M.; Pauwels, Valentijn; Reichle, Rolf H.; Draper, Clara; Koster, Randy; Liu, Qing

    2012-01-01

    Satellite-based microwave measurements have long shown potential to provide global information about soil moisture. The European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS, [1]) mission as well as the future National Aeronautics and Space Administration (NASA) Soil Moisture Active and Passive (SMAP, [2]) mission measure passive microwave emission at L-band frequencies, at a relatively coarse (40 km) spatial resolution. In addition, SMAP will measure active microwave signals at a higher spatial resolution (3 km). These new L-band missions have a greater sensing depth (of -5cm) compared with past and present C- and X-band microwave sensors. ESA currently also disseminates retrievals of SMOS surface soil moisture that are derived from SMOS brightness temperature observations and ancillary data. In this research, we address two major challenges with the assimilation of recent/future satellite-based microwave measurements: (i) assimilation of soil moisture retrievals versus brightness temperatures for surface and root-zone soil moisture estimation and (ii) scale-mismatches between satellite observations, models and in situ validation data.

  15. Automation of peanut drying with a sensor network including an in-shell kernel moisture sensor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peanut drying is an essential task in the processing and handling of peanuts. Peanuts leave the fields with kernel moisture contents > 20% wet basis and need to be dried to < 10.5% w.b. for grading and storage purposes. Current peanut drying processes utilize decision support software based on model...

  16. Advanced technologies for perimeter intrusion detection sensors

    SciTech Connect

    Williams, J.D.

    1995-03-01

    The development of integrated circuit fabrication techniques and the resulting devices have contributed more to the advancement of exterior intrusion detectors and alarm assessment devices than any other technology. The availability of this technology has led to the improvements in and further development of smaller more powerful computers, microprocessors, solid state memories, solid state cameras, thermal imagers, low-power lasers, and shorter pulse width and higher frequency electronic circuitry. This paper presents information on planning a perimeter intrusion detection system, identifies the site characteristics that affect its performance, and describes improvements to perimeter intrusion detection sensors and assessment devices that have been achieved by using integrated circuit technology.

  17. Uncooled thermal imaging sensor and application advances

    NASA Astrophysics Data System (ADS)

    Norton, Peter W.; Cox, Stephen; Murphy, Bob; Grealish, Kevin; Joswick, Mike; Denley, Brian; Feda, Frank; Elmali, Loriann; Kohin, Margaret

    2006-05-01

    BAE Systems continues to advance the technology and performance of microbolometer-based thermal imaging modules and systems. 640x480 digital uncooled infrared focal plane arrays are in full production, illustrated by recent production line test data for two thousand focal plane arrays. This paper presents a snapshot of microbolometer technology at BAE Systems and an overview of two of the most important thermal imaging sensor programs currently in production: a family of thermal weapons sights for the United States Army and a thermal imager for the remote weapons station on the Stryker vehicle.

  18. MISTRALE: Soil moisture mapping service based on a UAV-embedded GNSS-Reflectometry sensor

    NASA Astrophysics Data System (ADS)

    Van de Vyvere, Laura; Desenfans, Olivier

    2016-04-01

    Around 70 percent of worldwide freshwater is used by agriculture. To be able to feed an additional 2 billion people by 2030, water demand is expected to increase tremendously in the next decades. Farmers are challenged to produce "more crop per drop". In order to optimize water resource management, it is crucial to improve soil moisture situation awareness, which implies both a better temporal and spatial resolution. To this end, the objective of the MISTRALE project (Monitoring soIl moiSture and waTeR-flooded Areas for agricuLture and Environment) is to provide UAV-based soil moisture maps that could complement satellite-based and field measurements. In addition to helping farmers make more efficient decisions about where and when to irrigate, MISTRALE moisture maps are an invaluable tool for risk management and damage evaluation, as they provide highly relevant information for wetland and flood-prone area monitoring. In order to measure soil water content, a prototype of a new sensor, called GNSS-Reflectometry (GNSS-R), is being developed in MISTRALE. This approach consists in comparing the direct signal, i.e. the signal travelling directly from satellite to receiver (in this case, embedded in the UAV), with its ground-reflected equivalent. Since soil dielectric properties vary with moisture content, the reflected signal's peak power is affected by soil moisture, unlike the direct one. In order to mitigate the effect of soil surface roughness on measurements, both left-hand and right-hand circular polarization reflected signals have to be recorded and processed. When it comes to soil moisture, using GNSS signals instead of traditional visible/NIR imagery has many advantages: it is operational under cloud cover, during the night, and also under vegetation (bushes, grass, trees). In addition, compared to microwaves, GNSS signal (which lies in L-band, between 1.4 and 1.8 GHz) is less influenced by variation on thermal background. GNSS frequencies are then ideal

  19. Use of cosmic ray neutron sensors for soil moisture monitoring in forests

    NASA Astrophysics Data System (ADS)

    Heidbüchel, I.; Güntner, A.; Blume, T.

    2015-09-01

    Cosmic ray neutron sensors (CRS) are a promising technique to measure soil moisture at intermediate scales. To convert neutron counts to average volumetric soil water content a simple calibration function can be used (the N0-calibration of Desilets et al., 2010). This calibration function is based on soil water content derived directly from soil samples taken within the footprint of the sensor. We installed a CRS in a mixed forest in the lowlands of north-eastern Germany and calibrated it 10 times throughout one calendar year. Each calibration with the N0-calibration function resulted in a different CRS soil moisture time series, with deviations of up to 0.12 m3 m-3 for individual values of soil water content. Also, many of the calibration efforts resulted in time series that could not be matched with independent in situ measurements of soil water content. We therefore suggest a new calibration function with a different shape that can vary from one location to another. A two-point calibration proved to be adequate to correctly define the shape of the new calibration function if the calibration points were taken during both dry and wet conditions covering at least 50 % of the total range of soil moisture. The best results were obtained when the soil samples used for calibration were linearly weighted as a function of depth in the soil profile and non-linearly weighted as a function of distance from the CRS, and when the depth-specific amount of soil organic matter and lattice water content was explicitly considered. The annual cycle of tree foliation was found to be a negligible factor for calibration because the variable hydrogen mass in the leaves was small compared to the hydrogen mass changes by soil moisture variations. Finally, we provide a best practice calibration guide for CRS in forested environments.

  20. Use of cosmic ray neutron sensors for soil moisture monitoring in forests

    NASA Astrophysics Data System (ADS)

    Heidbüchel, Ingo; Güntner, Andreas; Blume, Theresa

    2016-04-01

    Measuring soil moisture with cosmic ray neutrons is a promising technique for intermediate spatial scales. To convert neutron counts to average volumetric soil water content a simple calibration function can be used (the N0-calibration of Desilets et al., 2010). The calibration is based on soil water content derived directly from soil samples taken within the footprint of the sensor. We installed a cosmic-ray neutron sensor (CRS) in a mixed forest in the lowlands of north-eastern Germany and calibrated it 10 times throughout one calendar year. Each calibration with the N0-calibration function resulted in a different CRS soil moisture time series, with deviations of up to 0.12 m3 m-3 for individual values of soil water content. Also, many of the calibration efforts resulted in time series that could not be matched with independent in situ measurements of soil water content. We therefore suggest a modified calibration function with a different shape that can vary from one location to another. A two-point calibration proved to be adequate to correctly define the shape of the modified calibration function if the calibration points were taken during both dry and wet conditions spanning at least half of the total range of soil moisture. The best results were obtained when the soil samples used for calibration were linearly weighted as a function of depth in the soil profile and non-linearly weighted as a function of distance from the CRS, and when the depth-specific amount of soil organic matter and lattice water content was explicitly considered. The annual cycle of tree foliation was found to be a negligible factor for calibration because the variable hydrogen mass in the leaves was small compared to the hydrogen mass changes by soil moisture variations. We will also provide a best practice calibration guide for CRS in forested environments.

  1. Use of cosmic-ray neutron sensors for soil moisture monitoring in forests

    NASA Astrophysics Data System (ADS)

    Heidbüchel, Ingo; Güntner, Andreas; Blume, Theresa

    2016-03-01

    Measuring soil moisture with cosmic-ray neutrons is a promising technique for intermediate spatial scales. To convert neutron counts to average volumetric soil water content a simple calibration function can be used (the N0-calibration of Desilets et al., 2010). The calibration is based on soil water content derived directly from soil samples taken within the footprint of the sensor. We installed a cosmic-ray neutron sensor (CRS) in a mixed forest in the lowlands of north-eastern Germany and calibrated it 10 times throughout one calendar year. Each calibration with the N0-calibration function resulted in a different CRS soil moisture time series, with deviations of up to 0.1 m3 m-3 (24 % of the total range) for individual values of soil water content. Also, many of the calibration efforts resulted in time series that could not be matched with independent in situ measurements of soil water content. We therefore suggest a modified calibration function with a different shape that can vary from one location to another. A two-point calibration was found to effectively define the shape of the modified calibration function if the calibration points were taken during both dry and wet conditions spanning at least half of the total range of soil moisture. The best results were obtained when the soil samples used for calibration were linearly weighted as a function of depth in the soil profile and nonlinearly weighted as a function of distance from the CRS, and when the depth-specific amount of soil organic matter and lattice water content was explicitly considered. The annual cycle of tree foliation was found to be a negligible factor for calibration because the variable hydrogen mass in the leaves was small compared to the hydrogen mass changes by soil moisture variations. As a final point, we provide a calibration guide for a CRS in forested environments.

  2. Assessing the capability of EOS sensors in measuring ocean-atmosphere moisture exchange

    NASA Technical Reports Server (NTRS)

    Liu, W. T.

    1985-01-01

    As part of the Science Synergism Studies to identify interdisciplinary Scientific studies, which could be addressed by the Environmental Observing System (EOS), the techniques being developed to measure ocean-atmosphere moisture exchanges using satellite sensors were evaluated. Studies required to use sensors proposed for EOS were examined. A method has been developed to compute the moisture flux using the wind speed, sea surface temperature, and preciptable water measured by satellite sensors. It relies on a statistical model which predicts surface-level humidity from precipitable water. The Scanning Multichannel Microwave Radiometer (SMMR) measures all 3 parameters and was found to be sensitive to the annual cycle and large interannual variations such as the 1982 to 1983 El Nino. There are systematic differences between geophysical parameters measured by Nimbus/SMMR and in situ measurements. After quadratic trends and crosstalks were removed from the parameters through multivariate regressions, the latent heat fluxes computed from SMMR agree with those computed from ship reports to within 30 W/sq m. The poor quality of ship reports may be the cause of a portion of this scatter. Similar results are found using SEASAT/SMMR data. When the scatterometer winds were used instead of the SMMR winds, the difference between the satellite fluxes and the ship fluxes was reduced.

  3. Field test of electromagnetic induction sensor GEM300 for soil moisture retrieval

    NASA Astrophysics Data System (ADS)

    Calamita, Giuseppe; Onorati, Beniamino; Brocca, Luca; Perrone, Angela; Manfreda, Salvatore; Moramarco, Tommaso; Margiotta, Maria Rosaria; Marrese, Rosalia

    2013-04-01

    Soil moisture represents a key variable for several hydrological processes acting at hill-slope and small-catchment scale (104-107 m2). Through the classical indirect ground-based methods such as Time Domain Reflectometry (TDR) and capacitance sensors, the attention has been focusing on accuracy and precision at the small (point) scale, whereas their application over large areas has proven to be impractical and relatively expensive. In fact, considering the small sampling volume involved in the measurements, a high number of sampling sites might be required to achieve an acceptable spatial accuracy thus making the scaling-up of soil moisture measurements still problematic. Beside this, the operational difficulties that can easily arise on hard, dry or stony soils often inhibit the use of classical methods. During the last decade, a considerable interest in the hydrological community has arisen on the opportunity to move from high-precision and high-accuracy point-scale measurements to a large number of measurements over a large area with a lower precision and accuracy. In this context, geophysical methods, such as the electromagnetic induction (EMI), are potential candidate to support the study of soil moisture dynamics because of competitive costs, higher acquisition rate, easy of use, not invasive, etc. However, although the electrical resistivity is theoretically linked with soil moisture, the interpretation of electrical resistivity measurements is not straightforward, because of the influence of other soil factors. In this study, we present the preliminary results related to the comparison between a set of volumetric soil moisture measurements carried out by both portable and buried TDR probes, and the bulk soil electrical conductivity measurements collected through the GEM-300, a multi-frequency EMI sensor. The measurements were carried out in an experimental small-basin named Fiumarella di Corleto, located in Basilicata region (southern Italy). Three test

  4. Atmospheric attenuation relative to earth-viewing orbital sensors. [atmospheric moisture effects on microwaves

    NASA Technical Reports Server (NTRS)

    Brown, S. C.; Jayroe, R. R., Jr.

    1973-01-01

    Earth viewing space missions offer exciting new possibilities in several earth resources disciplines - geography, hydrology, agriculture, geology, and oceanography, to name a few. A most useful tool in planning experiments and applying space technology to earth observation is a statistical description of atmospheric parameters. Four dimensional atmospheric models and a world wide cloud model are used to produce atmospheric attenuation models to predict degradation effects for all classes of sensors for application to earth sensing experiments from spaceborne platforms. To insure maximum utility and application of these products, the development of an interaction model of microwave energy and atmospheric variables provides a complete description of the effects of atmospheric moisture upon microwaves.

  5. Advanced Sensor Technologies for Next-Generation Vehicles

    SciTech Connect

    Sheen, S H; Chien, H T; Gopalsami, N; Jendrzejczyk, A; Raptis, A C

    2002-01-30

    This report summarizes the development of automobile emissions sensors at Argonne National Laboratory. Three types of sensor technologies, i.e., ultrasound, microwave, and ion-mobility spectrometry (IMS), were evaluated for engine-out emissions monitoring. Two acoustic sensor technologies, i.e., surface acoustic wave and flexural plate wave, were evaluated for detection of hydrocarbons. The microwave technique involves a cavity design and measures the shifts in resonance frequency that are a result of the presence of trace organic compounds. The IMS technique was chosen for further development into a practical emissions sensor. An IMS sensor with a radioactive {sup 63}Ni ion source was initially developed and applied to measurement of hydrocarbons and NO{sub x} emissions. For practical applications, corona and spark discharge ion sources were later developed and applied to NO{sub x} emission measurement. The concentrations of NO{sub 2} in dry nitrogen and in a typical exhaust gas mixture are presented. The sensor response to moisture was evaluated, and a cooling method to control the moisture content in the gas stream was examined. Results show that the moisture effect can be reduced by using a thermoelectric cold plate. The design and performance of a laboratory prototype sensor are described.

  6. Field Measurements and Numerical Simulations of Temperature and Moisture in Highway Engineering Using a Frequency Domain Reflectometry Sensor.

    PubMed

    Yao, Yong-Sheng; Zheng, Jian-Long; Chen, Zeng-Shun; Zhang, Jun-Hui; Li, Yong

    2016-01-01

    This paper presents a systematic pioneering study on the use of agricultural-purpose frequency domain reflectometry (FDR) sensors to monitor temperature and moisture of a subgrade in highway extension and reconstruction engineering. The principle of agricultural-purpose FDR sensors and the process for embedding this kind of sensors for subgrade engineering purposes are introduced. Based on field measured weather data, a numerical analysis model for temperature and moisture content in the subgrade's soil is built. Comparisons of the temperature and moisture data obtained from numerical simulation and FDR-based measurements are conducted. The results show that: (1) the embedding method and process, data acquisition, and remote transmission presented are reasonable; (2) the temperature and moisture changes are coordinated with the atmospheric environment and they are also in close agreement with numerical calculations; (3) the change laws of both are consistent at positions where the subgrade is compacted uniformly. These results suggest that the data measured by the agricultural-purpose FDR sensors are reliable. The findings of this paper enable a new and effective real-time monitoring method for a subgrade's temperature and moisture changes, and thus broaden the application of agricultural-purpose FDR sensors. PMID:27294935

  7. Field Measurements and Numerical Simulations of Temperature and Moisture in Highway Engineering Using a Frequency Domain Reflectometry Sensor

    PubMed Central

    Yao, Yong-Sheng; Zheng, Jian-Long; Chen, Zeng-Shun; Zhang, Jun-Hui; Li, Yong

    2016-01-01

    This paper presents a systematic pioneering study on the use of agricultural-purpose frequency domain reflectometry (FDR) sensors to monitor temperature and moisture of a subgrade in highway extension and reconstruction engineering. The principle of agricultural-purpose FDR sensors and the process for embedding this kind of sensors for subgrade engineering purposes are introduced. Based on field measured weather data, a numerical analysis model for temperature and moisture content in the subgrade’s soil is built. Comparisons of the temperature and moisture data obtained from numerical simulation and FDR-based measurements are conducted. The results show that: (1) the embedding method and process, data acquisition, and remote transmission presented are reasonable; (2) the temperature and moisture changes are coordinated with the atmospheric environment and they are also in close agreement with numerical calculations; (3) the change laws of both are consistent at positions where the subgrade is compacted uniformly. These results suggest that the data measured by the agricultural-purpose FDR sensors are reliable. The findings of this paper enable a new and effective real-time monitoring method for a subgrade’s temperature and moisture changes, and thus broaden the application of agricultural-purpose FDR sensors. PMID:27294935

  8. Control Software for Advanced Video Guidance Sensor

    NASA Technical Reports Server (NTRS)

    Howard, Richard T.; Book, Michael L.; Bryan, Thomas C.

    2006-01-01

    Embedded software has been developed specifically for controlling an Advanced Video Guidance Sensor (AVGS). A Video Guidance Sensor is an optoelectronic system that provides guidance for automated docking of two vehicles. Such a system includes pulsed laser diodes and a video camera, the output of which is digitized. From the positions of digitized target images and known geometric relationships, the relative position and orientation of the vehicles are computed. The present software consists of two subprograms running in two processors that are parts of the AVGS. The subprogram in the first processor receives commands from an external source, checks the commands for correctness, performs commanded non-image-data-processing control functions, and sends image data processing parts of commands to the second processor. The subprogram in the second processor processes image data as commanded. Upon power-up, the software performs basic tests of functionality, then effects a transition to a standby mode. When a command is received, the software goes into one of several operational modes (e.g. acquisition or tracking). The software then returns, to the external source, the data appropriate to the command.

  9. Soil Moisture Monitoring Network Using Multi-Sensor Capacitance Probes in a Thick Vadose Zone Under Riparian Vegetation

    NASA Astrophysics Data System (ADS)

    Solis, J. A.; Rajaram, H.

    2011-12-01

    Soil moisture profile measurements are an integral component of water balance estimation networks, especially in thick vadose zones and fine-grained soil environments. At field sites with silty and stiff clayey soils, installation of sensors at multiple depths poses a challenge. One approach that has gained popularity is a multi-sensor capacitance (EniroSCAN) probe system manufactured by Sentek technologies. This requires only a single borehole where a 56.5 mm PVC access tube is installed. A very attractive feature of this system is that the sensors can be positioned at different depths without having to disturb the soil since the sensors are located on a cartridge unit that rides within the access tube and can be moved in 10 cm increments. We report the design and installation of a distributed soil moisture sensor network in a riparian zone within the Whitewater Basin in Central Kansas. The soil-moisture monitoring network used in this study is compromised of 6 profilers (each covering a depth of 2 m) with 4-5 sensors per profile, located at different depths. The network is connected to a centralized data logger, from which it can be accessed remotely through a telemetry system in real-time. The network obtains distributed soil moisture measurements every 15 minutes. All profilers exhibit a rapid response to precipitation events at depths < 1m. During the leaf-out stage, sensors at depths < 1.5 m exhibit diurnal fluctuations in response to plant water uptake. The temporal trends and response to rainfall/plant uptake is significantly different at the different profile locations, illustrating the significant heterogeneity at the site. The moisture profiles clearly demonstrate the gradual replenishment of soil moisture both by precipitation and capillary rise during fall and winter, followed by depletion (with diurnal variations superimposed) during the leaf-out stage of riparian vegetation. We describe the calibration efforts needed to convert the dielectric

  10. Orbital Express Advanced Video Guidance Sensor

    NASA Technical Reports Server (NTRS)

    Howard, Ricky; Heaton, Andy; Pinson, Robin; Carrington, Connie

    2008-01-01

    In May 2007 the first US fully autonomous rendezvous and capture was successfully performed by DARPA's Orbital Express (OE) mission. Since then, the Boeing ASTRO spacecraft and the Ball Aerospace NEXTSat have performed multiple rendezvous and docking maneuvers to demonstrate the technologies needed for satellite servicing. MSFC's Advanced Video Guidance Sensor (AVGS) is a primary near-field proximity operations sensor integrated into ASTRO's Autonomous Rendezvous and Capture Sensor System (ARCSS), which provides relative state knowledge to the ASTRO GN&C system. This paper provides an overview of the AVGS sensor flying on Orbital Express, and a summary of the ground testing and on-orbit performance of the AVGS for OE. The AVGS is a laser-based system that is capable of providing range and bearing at midrange distances and full six degree-of-freedom (6DOF) knowledge at near fields. The sensor fires lasers at two different frequencies to illuminate the Long Range Targets (LRTs) and the Short Range Targets (SRTs) on NEXTSat. Subtraction of one image from the other image removes extraneous light sources and reflections from anything other than the corner cubes on the LRTs and SRTs. This feature has played a significant role for Orbital Express in poor lighting conditions. The very bright spots that remain in the subtracted image are processed by the target recognition algorithms and the inverse-perspective algorithms, to provide 3DOF or 6DOF relative state information. Although Orbital Express has configured the ASTRO ARCSS system to only use AVGS at ranges of 120 m or less, some OE scenarios have provided opportunities for AVGS to acquire and track NEXTSat at greater distances. Orbital Express scenarios to date that have utilized AVGS include a berthing operation performed by the ASTRO robotic arm, sensor checkout maneuvers performed by the ASTRO robotic arm, 10-m unmated operations, 30-m unmated operations, and Scenario 3-1 anomaly recovery. The AVGS performed very

  11. Advances in the use of Distributed Temperature Sensing for measuring soil moisture

    NASA Astrophysics Data System (ADS)

    Steele-Dunne, S. C.; Dong, J.; Ochsner, T. E.; Van De Giesen, N.

    2014-12-01

    This presentation will focus on advances in the use of passive distributed temperature sensing for large-scale, high resolution monitoring of soil moisture. In this approach, cables are plowed into the ground at several depths and use to make continuous measurements of soil temperature. Unlike Active DTS, external heating is not applied to the cables. The soil temperature profile variations in response to the diurnal net radiation cycle are observed instead. Recent results will be presented from an improved inversion approach, in which the vertical profile of thermal diffusivity is inferred from the cable temperatures and limited ancillary information. Results will also be presented from a promising new data assimilation approach, in which temperature observations are assimilated into a model to obtain simultaneous soil moisture and temperature profiles. This approach is particularly well suited to handling the vertical and horizontal spatial variability in moisture content and soil texture. It is less sensitive to errors in cable depth than the inversion method and circumvents the problem of inferring one of two possible soil moisture values from a thermal diffusivity estimate. We will conclude with some perspectives on how this approach can be extended to facilitate the combined use of active and passive DTS for soil moisture estimation.

  12. Impact of stone content on soil moisture measurement with capacitive sensors 10HS (Decagon)

    NASA Astrophysics Data System (ADS)

    Deraedt, Deborah; Bernard, Julien; Bietlot, Louise; Clerbois, Laura; Rosière, Clément; Starren, Amandine; Colinet, Gilles; Mercatoris, Benoit; Degré, Aurore

    2015-04-01

    Lot of soil survey focused on agricultural soils. For practical reasons, those soils have a low stone content. So, most of the soil water content sensors are placed on low stone content soils and the calibration equations are developed for them. Yet some researches take an interest in forest soils that are often much different from the previous ones. The differences lie in their stone content and their slope. Lots of studies have proved the importance of making soil specific calibration of the soil water content sensor. As our lab use regularly the 10HS sensors (Decagon Devices, United States) in forested soil, we decided to evaluate the importance of the stone content in the soil moisture measurement. The soil used for this experimentation comes from Gembloux (50°33'54.9''N, 4°42'11.3''E). It is silt that has been sieved at 2 mm to remove the gravel. The stones used to form the samples come from an experimental site located in the Belgian Ardennes (50°1'52.6''N, 4°53'22.5''E). They are mainly composed of schist with some quartz and sandstone elements. Initially, only five samples were constructed with three replications each. The size and the proportion of stones were the variables. Stones were classified in two groups, the first contains gravels whose size is less than 1,5 cm and a the second contains gravels whose size is comprised between 2 and 3 cm. The proportions of stone selected for the experiment are 0, 20 and 40%. In order to generate validation data, two more samples were constructed with intermediate proportion of stone content (30%). The samples were built in PVC container which dimensions are slightly bigger than the sensor volume of influence (1.1-1.3l). The soil samples were saturated and then dried on a thermal chamber set at about 32°C. During at least 14 days, the samples soil water content was determined by the sensor measurement with the Procheck read-out system (Decagon Devices, United State) and by weighting the samples thrice a day

  13. [Performance characteristics of root zone moisture and water potential sensors for greenhouses in the conditions of extended space flight].

    PubMed

    Podolskiy, I G; Strugov, O M; Bingham, G E

    2014-01-01

    The investigation was performed using greenhouse Lada in the Russian segment of the International space station (ISS RS) as part of space experiment Plants-2 during ISS missions 5 through to 22. A set of 6 point moisture sensors embedded in the root zone (turface particles of 1-2 mm in diam.) and 4 tensiometers inside root modules (RM) were used to monitor moisture content and water potential in the root zone. The purpose was to verify functionality and to test performance of the sensors in the spacefight environment. It was shown that with the average RZ moisture content of 80% the measurement error of the sensors do not exceed ± 1.5%. Dynamic analysis of the tensiometers measurements attests that error in water potential measurements does not exceed ± 111 Pa. PMID:26035998

  14. Advances and trends in ionophore-based chemical sensors

    NASA Astrophysics Data System (ADS)

    Mikhelson, K. N.; Peshkova, M. A.

    2015-06-01

    The recent advances in the theory and practice of potentiometric, conductometric and optical sensors based on ionophores are critically reviewed. The role of the heterogeneity of the sensor/sample systems is emphasized, and it is shown that due to this heterogeneity such sensors respond to the analyte activities rather than to concentrations. The basics of the origin of the response of all three kinds of ionophore-based sensors are briefly described. The use of novel sensor materials, new preparation and application techniques of the sensors as well as advances in theoretical treatment of the sensor response are analyzed using literature sources published mainly from 2012 to 2014. The basic achievements made in the past are also addressed when necessary for better understanding of the trends in the field of ionophore-based sensors. The bibliography includes 295 references.

  15. Advances in artificial olfaction: sensors and applications.

    PubMed

    Gutiérrez, J; Horrillo, M C

    2014-06-01

    The artificial olfaction, based on electronic systems (electronic noses), includes three basic functions that operate on an odorant: a sample handler, an array of gas sensors, and a signal-processing method. The response of these artificial systems can be the identity of the odorant, an estimate concentration of the odorant, or characteristic properties of the odour as might be perceived by a human. These electronic noses are bio inspired instruments that mimic the sense of smell. The complexity of most odorants makes characterisation difficult with conventional analysis techniques, such as gas chromatography. Sensory analysis by a panel of experts is a costly process since it requires trained people who can work for only relatively short periods of time. The electronic noses are easy to build, provide short analysis times, in real time and on-line, and show high sensitivity and selectivity to the tested odorants. These systems are non-destructive techniques used to characterise odorants in diverse applications linked with the quality of life such as: control of foods, environmental quality, citizen security or clinical diagnostics. However, there is much research still to be done especially with regard to new materials and sensors technology, data processing, interpretation and validation of results. This work examines the main features of modern electronic noses and their most important applications in the environmental, and security fields. The above mentioned main components of an electronic nose (sample handling system, more advanced materials and methods for sensing, and data processing system) are described. Finally, some interesting remarks concerning the strengths and weaknesses of electronic noses in the different applications are also mentioned. PMID:24767451

  16. Soil Moisture Monitoring Using GNSS-R Signals; First Experimental Results with the SAM Sensor

    NASA Astrophysics Data System (ADS)

    Egido, A.; Martin-Puig, C.; Felip, D.; Garcia, M.; Caparrini, M.; Farres, E.; Ruffini, G.

    2009-04-01

    Observing the Earth surface with Global Navigation Satellite Systems (GNSS) reflected signals has become a noteworthy remote sensing technique for the scientific community. The growing interest in GNSS as a remote sensing tool is due to its global availability and the carrier frequencies used. In fact, L-band, in which all current and next-future Global Navigation Satellite Systems emit, is a portion of the electromagnetic spectrum that highly interacts with the natural medium and for this reason, the possible applications exploiting these signals are numerous. In addition, the large number of GNSS signals in space, and their steadily increasing quantity and quality predicts a promising future for this remote sensing technique. Among a wide variety of applications, soil moisture (SM) monitoring represents an important niche for GNSS-R. SM is a prime parameter for the surface hydrologic cycle since it drives the evapotranspiration and the heat storage capability of the soil, as well as determines the possibility of surface runoff after rainfalls. Despite the recognised environmental and commercial relevance of SM, providing such parameter over global and large scales remains a significant challenge. Sensors based on GNSS-R offer a suitable and efficient solution to this issue. The basis for the retrieval of SM with GNSS-R systems lays in the variability of the ground dielectric properties associated to water content. The higher the concentration of water in the soil, the higher the dielectric constant and reflectivity, which affects signals that reflect from the Earth surface by increasing their peak power. Previous investigations, [1,2] demonstrated the capability of GPS bistatic scatterometers to sense small changes in surface reflectivity, becoming a precedent for this promising research line. GNSS-R present various advantages with respect to others methods currently used to retrieve soil moisture. Firstly, as already mentioned, GNSS signals lie in L band, which

  17. Advancing Profiling Sensors with a Wireless Approach

    PubMed Central

    Galvis, Alex; Russomanno, David J.

    2012-01-01

    The notion of a profiling sensor was first realized by a Near-Infrared (N-IR) retro-reflective prototype consisting of a vertical column of wired sparse detectors. This paper extends that prior work and presents a wireless version of a profiling sensor as a collection of sensor nodes. The sensor incorporates wireless sensing elements, a distributed data collection and aggregation scheme, and an enhanced classification technique. In this novel approach, a base station pre-processes the data collected from the sensor nodes and performs data re-alignment. A back-propagation neural network was also developed for the wireless version of the N-IR profiling sensor that classifies objects into the broad categories of human, animal or vehicle with an accuracy of approximately 94%. These enhancements improve deployment options as compared with the first generation of wired profiling sensors, possibly increasing the application scenarios for such sensors, including intelligent fence applications. PMID:23443371

  18. Long term soil moisture mapping over the Tibetan plateau using Special Sensor Microwave/Imager

    NASA Astrophysics Data System (ADS)

    van der Velde, R.; Salama, M. S.; Pellarin, T.; Ofwono, M.; Ma, Y.; Su, Z.

    2014-04-01

    This paper discusses soil moisture retrievals over the Tibetan Plateau from brightness temperature (TB's) observed by the Special Sensor Microwave Imagers (SSM/I's) during the warm seasons of the period from July 1987 to December 2008. The Fundamental Climate Data Record (FCDR) of F08, F11 and F13 SSM/I satellites by the Precipitation Research Group of Colorado State University is used for this study. A soil moisture retrieval algorithm is developed based on a radiative transfer model that simulates top-of-atmosphere TB's whereby effects of atmosphere are calculated from near-surface forcings obtained from a bias-corrected dataset. Validation of SSM/I retrievals against in situ measurements for a two-and-half year period (225 matchups) gives a Root Mean Squared Error of 0.046 m3 m-3. The agreement between retrievals and Noah simulations from the Global Land Data Assimilation System is investigated to further provide confidence in the reliability of SSM/I retrievals at the Plateau-scale. Normalised soil moisture anomalies (N) are computed on a warm seasonal (May-October) and on a monthly basis to analyse the trends present within the products available from July 1987 to December 2008. The slope of linear regression functions between N and time is used to quantify the trends. Both the warm season and monthly N indicate severe wettings of 0.8 to almost 1.6 decade-1 in the centre of the Plateau. Correlations are found by the trend with elevation for the warm season as a whole and the individual months May, September and October. The observed wetting of the Tibetan Plateau agrees with recent findings on permafrost retreat, precipitation increase and potential evapotranspiration decline.

  19. Long term soil moisture mapping over the Tibetan Plateau using Special Sensor Microwave/Imager

    NASA Astrophysics Data System (ADS)

    van der Velde, R.; Salama, M. S.; Pellarin, T.; Ofwono, M.; Ma, Y.; Su, Z.

    2013-05-01

    This paper discusses soil moisture retrievals over the Tibetan Plateau from brightness temperature (TB's) observed by the Special Sensor Microwave Imagers (SSM/I's) during warm seasons of the period from July 1987 to December 2008. The Fundamental Climate Data Record (FCDR) of F08, F11 and F13 SSM/I satellites by the Precipitation Research Group of Colorado State University is used for this study. A soil moisture retrieval algorithm is developed based on a radiative transfer model that simulates top-of-atmosphere TB's whereby effects of atmosphere are calculated from near-surface forcings obtained from a bias-corrected data set. Validation of SSM/I retrievals against in situ measurements for a two-and-half year period (225 matchups) gives a Root Mean Squared Error of 0.046 m3 m-3. The agreement between retrievals and Noah simulations from the Global Land Data Assimilation System (GLDAS) is investigated to further provide confidence in the reliability of SSM/I retrievals at the plateau-scale. Normalized soil moisture anomalies (N) are computed on an annual and monthly basis to analyze the trends present within the products available for July 1987 to December 2008. The slope of linear regression functions between N and time is used to quantify the trends. Both the annual and monthly N indicate severe wettings of 0.8 to almost 1.6 decade-1 in the center of the plateau. Correlations are found of the trend with elevation on an annual basis and for the months May, September and October. The observed wetting of the Tibetan Plateau agrees with recent findings of permafrost retreat, precipitation increase and potential evapotranspiration decline.

  20. Feed-Back Moisture Sensor Control for the Delivery of Water to Plants Cultivated in Space

    NASA Technical Reports Server (NTRS)

    Levine, Howard G.; Prenger, Jessica J.; Rouzan, Donna T.; Spinale, April C.; Murdoch, Trevor; Burtness, Kevin A.

    2005-01-01

    The development of a spaceflight-rated Porous Tube Insert Module (PTIM) nutrient delivery tray has facilitated a series of studies evaluating various aspects of water and nutrient delivery to plants as they would be cultivated in space. We report here on our first experiment using the PTIM with a software-driven feedback moisture sensor control strategy for maintaining root zone wetness level set-points. One-day-old wheat seedlings (Tritium aestivum cv Apogee; N=15) were inserted into each of three Substrate Compartments (SCs) pre-packed with 0.25-1 . mm Profile(TradeMark) substrate and maintained at root zone relative water content levels of 70, 80 and 90%. The SCs contained a bottom-situated porous tube around which a capillary mat was wrapped. Three Porous Tubes. were planted using similar protocols (but without the substrate) and also maintained at these three moisture level set-points. Half-strength modified Hoagland's nutrient solution was used to supply water and nutrients. Results on hardware performance, water usage rates and wheat developmental differences between the different experimental treatments are presented.

  1. Next Generation Advanced Video Guidance Sensor Development and Test

    NASA Technical Reports Server (NTRS)

    Howard, Richard T.; Bryan, Thomas C.; Lee, Jimmy; Robertson, Bryan

    2009-01-01

    The Advanced Video Guidance Sensor (AVGS) was the primary docking sensor for the Orbital Express mission. The sensor performed extremely well during the mission, and the technology has been proven on orbit in other flights too. Parts obsolescence issues prevented the construction of more AVGS units, so the next generation of sensor was designed with current parts and updated to support future programs. The Next Generation Advanced Video Guidance Sensor (NGAVGS) has been tested as a breadboard, two different brassboard units, and a prototype. The testing revealed further improvements that could be made and demonstrated capability beyond that ever demonstrated by the sensor on orbit. This paper presents some of the sensor history, parts obsolescence issues, radiation concerns, and software improvements to the NGAVGS. In addition, some of the testing and test results are presented. The NGAVGS has shown that it will meet the general requirements for any space proximity operations or docking need.

  2. The accuracy and calibration of three cotton bale moisture sensors used in a commercial gin with lint moisture restoration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Proper measurement of bale moisture content (mc) is crucial to proper management of a cotton gin. It is important to avoid producing wet cotton, unacceptable for Commodity Credit Corporation Marketing Assistance Loan Program, which is defined to be a bale of cotton which is at or above 7.5% wet bas...

  3. The accuracy of cotton bale moisture sensors used in a South Texas commercial gin with lint moisture restoration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Proper measurement of bale moisture content (mc) is crucial to proper management of a cotton gin. It is important to avoid producing wet cotton both for the benefit of the mills and because wet cotton is unacceptable for Commodity Credit Corporation Marketing Assistance Loan Program. Wet cotton is...

  4. Application of discrete wavelet analysis for moisture content estimation of in-shell nuts nondestructively with a capacitance sensor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Moisture content is an important quality factors often measured and monitored in the processing and storage of food products such as corn and peanuts. For estimating this parameter for peanuts nondestructively a parallel-plate capacitance sensor was used in conjunction with an impedance analyzer. ...

  5. Estimation of moisture and oil content of in-shell nuts with a capacitance sensor using discrete wavelet analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    . Moisture and oil contents are important quality factors often measured and monitored in the processing and storage of food products such as corn and peanuts. For estimating these parameters for peanuts nondestructively a parallel-plate capacitance sensor was used in conjunction with an impedance...

  6. PARALLEL-PLATE SENSORS FOR MEASUREMENT OF MOISTURE CONTENT IN IN-SHELL PEANUTS NON-DESTRUCTIVELY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In earlier work reported, parallel-plate capacitance sensors were used to determine the average moisture content (MC) of small samples of in-shell peanuts (peanut pods). In this method, seven or eight peanut pods were held between two parallel metal electrodes and the capacitance, phase angle and/o...

  7. Analysis of soil moisture retrieval from airborne passive/active L-band sensor measurements in SMAPVEX 2012

    NASA Astrophysics Data System (ADS)

    Chen, Liang; Song, Hongting; Tan, Lei; Li, Yinan; Li, Hao

    2014-11-01

    Soil moisture is a key component in the hydrologic cycle and climate system. It is an important input parameter for many hydrologic and meteorological models. NASA'S upcoming Soil Moisture Active Passive (SMAP) mission, to be launched in October 2014, will address this need by utilizing passive and active microwave measurements at L-band, which will penetrate moderately dense canopies. In preparation for the SMAP mission, the Soil Moisture Validation Experiment 2012 (SMAPVEX12) was conducted from 6 June to 17 July 2012 in the Carment-Elm Creek area in Manitoba, Canada. Over a period of six weeks diverse land cover types ranging from agriculture over pasture and grassland to forested sites were re-visited several times a week. The Passive/Active L-band Sensor (PALS) provides radiometer products, vertically and horizontally polarized brightness temperatures, and radar products. Over the past two decades, successful estimation of soil moisture has been accomplished using passive and active L-band data. However, remaining uncertainties related to surface roughness and the absorption, scattering, and emission by vegetation must be resolved before soil moisture retrieval algorithms can be applied with known and acceptable accuracy using satellite observations. This work focuses on analyzing the Passive/Active L-band Sensor observations of sites covered during SMAPVEX12, investigating the observed data, parameterizing vegetation covered surface model, modeling inversion algorithm and analyzing observed soil moisture changes over the time period of six weeks. The data and analysis results from this study are aimed at increasing the accuracy and range of validity of SMAP soil moisture retrievals via enhancing the accuracy for soil moisture retrieval.

  8. A Non-Invasive Phase Sensor for Permittivity and Moisture Estimation Based on Anomalous Dispersion.

    PubMed

    Siddiqui, Omar; Ramzan, Rashad; Amin, Muhammad; Ramahi, Omar M

    2016-01-01

    The traditional microwave resonance sensors are based on the measurement of the frequency shift and bandwidth of a resonator's amplitude spectrum. Here we propose a novel sensing scheme in which the material properties are estimated by determining the changes in the phase spectrum of an anomalous-phase resonator. In the proposed phase sensing, we exploit the unique double phase reversal which takes place on the edges of the anomalous dispersion region as a signature to detect the resonance. We show that with the phase sensing, a significant reduction in detection errors compared to the traditional sensing can be obtained because of the noise immunity offered by the phase detection and also due to the strong dispersive phase response that reduces the sensor's dependence on the external environment. We also show that the bandwidth determination procedure of the resonance which is needed to characterize the sample losses is significantly simplified. The concept of phase sensing is shown by devising an experimental microstrip open stub resonator whose frequency response lies in the anomalous dispersion region. The dielectric characteristics of the samples placed on the stub are extracted from the resonant frequency and the slope of the phase response. We also demonstrate that the changes in moisture levels can also be detected by utilizing the phase sensing method. PMID:27346337

  9. Advances in sapphire optical fiber sensors

    NASA Technical Reports Server (NTRS)

    Wang, Anbo; Wang, George Z.; Gollapudi, Sridhar; May, Russell G.; Murphy, Kent A.; Claus, Richard O.

    1993-01-01

    We describe the development and testing of two sapphire fiber sensor designs intended for use in high temperature environments. The first is a birefringence-balanced polarimetric sapphire fiber sensor. In this sensor, two single crystal sapphire rods, acting as the birefringence sensing element, are connected to each other in such a way that the slow axis of the first rod is aligned along with the fast axis of the second rod, and the fast axis of the first rod is along the slow axis of the second rod. This sensor has been demonstrated for measurement of temperature up to 1500 C. The second is a sapphire-fiber-based intrinsic interferometric sensor. In this sensor, a length of uncoated, unclad, structural-graded multimode sapphire fiber is fusion spliced to a singlemode silica fiber to form a Fabry-Perot cavity. The reflections from the silica-to-sapphire fiber splice and the free endface of the sapphire fiber give rise to the interfering fringe output. This sensor has been demonstrated for the measurement of temperature above 1510 C, and a resolution of 0.1 C has been obtained.

  10. Advanced EMU electrochemically regenerable CO2 and moisture absorber module breadboard

    NASA Technical Reports Server (NTRS)

    Lee, M. C.; Sudar, M.; Chang, B. J.

    1988-01-01

    The applicability of the Electrochemically Regenerable Carbon Dioxide and Moisture Absorption Technology to the advanced extravehicular mobility unit was demonstrated by designing, fabricating, and testing a breadboard Absorber Module and an Electrochemical Regenerator. Test results indicated that the absorber module meets or exceeds the carbon dioxide removal requirements specified for the design and can meet the moisture removal requirement when proper cooling is provided. CO2 concentration in the vent gas stream was reduced from 0.52 to 0.027 kPa (3.9 to 0.20 mm Hg) for the full five hour test period. Vent gas dew point was reduced from inlet values of 294 K (69 F) to 278 K (41 F) at the outlet. The regeneration of expended absorbent was achieved by the electrochemical method employed in the testing. An absorbent bed using microporous hydrophobic membrane sheets with circulating absorbent is shown to be the best approach to the design of an Absorber Module based on sizing and performance. Absorber Module safety design, comparison of various absorbents and their characteristics, moisture absorption and cooling study and subsystem design and operation time-lining study were also performed.

  11. Advancing Sensor Technology for Aerospace Propulsion

    NASA Technical Reports Server (NTRS)

    Figueroa, Fernando; Mercer, Carolyn R.

    2002-01-01

    NASA's Stennis Space Center (SSC) and Glenn Research Center (GRC) participate in the development of technologies for propulsion testing and propulsion applications in air and space transportation. Future transportation systems and the test facilities needed to develop and sustain them are becoming increasingly complex. Sensor technology is a fundamental pillar that makes possible development of complex systems that must operate in automatic mode (closed loop systems), or even in assisted-autonomous mode (highly self-sufficient systems such as planetary exploration spacecraft). Hence, a great deal of effort is dedicated to develop new sensors and related technologies to be used in research facilities, test facilities, and in vehicles and equipment. This paper describes sensor technologies being developed and in use at SSC and GRC, including new technologies in integrated health management involving sensors, components, processes, and vehicles.

  12. A capacitance sensor for water: trace moisture measurement in gases and organic solvents.

    PubMed

    Ohira, Shin-Ichi; Goto, Kayoko; Toda, Kei; Dasgupta, Purnendu K

    2012-10-16

    The determination of water in various matrices is one of the most important analytical measurements. We report on a high-resolution capacitance-based moisture sensor utilizing a thin film of a perfluorosulfonate ionomer (PFSI)-H(3)PO(4) composite in a flow-through configuration, for both gas and liquid samples. Incorporation of H(3)PO(4) into a PFSI sensing film improved the limit of detection (LOD) (signal-to-noise ratio, S/N = 3) by a factor of 16 in the gas phase to 0.075% relative humidity (RH) (dew point = -56 °C). The response time was dependent on the sensing film thickness and composition and was as low as ∼60 ms. The temperature dependence of the sensor response, and its relative selectivity over alcohol and various other solvents, are reported. Measurement of water in organic solvents was carried out in two different ways. In one procedure, the sample was vaporized and swept into the detector (e.g., in a gas chromatograph (GC) without a column); it permitted a throughput of 80 samples/h. This is well-suited for higher (%) levels of water. In the other method, a flow injection analysis system integrated to a tubular dialysis membrane pervaporizer (PV-FIA) was used; the LOD for water in ethanol was 0.019% (w/w). We demonstrated the temporal course of drying of ethanol by Drierite; the PV-FIA results showed excellent correspondence (r(2) > 0.99) with results from GC-thermal conductivity detection. The system can measure trace water in many types of organic solvents; no reagent consumption is involved. PMID:22962839

  13. A Non-Invasive Phase Sensor for Permittivity and Moisture Estimation Based on Anomalous Dispersion

    NASA Astrophysics Data System (ADS)

    Siddiqui, Omar; Ramzan, Rashad; Amin, Muhammad; Ramahi, Omar M.

    2016-06-01

    The traditional microwave resonance sensors are based on the measurement of the frequency shift and bandwidth of a resonator’s amplitude spectrum. Here we propose a novel sensing scheme in which the material properties are estimated by determining the changes in the phase spectrum of an anomalous-phase resonator. In the proposed phase sensing, we exploit the unique double phase reversal which takes place on the edges of the anomalous dispersion region as a signature to detect the resonance. We show that with the phase sensing, a significant reduction in detection errors compared to the traditional sensing can be obtained because of the noise immunity offered by the phase detection and also due to the strong dispersive phase response that reduces the sensor’s dependence on the external environment. We also show that the bandwidth determination procedure of the resonance which is needed to characterize the sample losses is significantly simplified. The concept of phase sensing is shown by devising an experimental microstrip open stub resonator whose frequency response lies in the anomalous dispersion region. The dielectric characteristics of the samples placed on the stub are extracted from the resonant frequency and the slope of the phase response. We also demonstrate that the changes in moisture levels can also be detected by utilizing the phase sensing method.

  14. A Non-Invasive Phase Sensor for Permittivity and Moisture Estimation Based on Anomalous Dispersion

    PubMed Central

    Siddiqui, Omar; Ramzan, Rashad; Amin, Muhammad; Ramahi, Omar M.

    2016-01-01

    The traditional microwave resonance sensors are based on the measurement of the frequency shift and bandwidth of a resonator’s amplitude spectrum. Here we propose a novel sensing scheme in which the material properties are estimated by determining the changes in the phase spectrum of an anomalous-phase resonator. In the proposed phase sensing, we exploit the unique double phase reversal which takes place on the edges of the anomalous dispersion region as a signature to detect the resonance. We show that with the phase sensing, a significant reduction in detection errors compared to the traditional sensing can be obtained because of the noise immunity offered by the phase detection and also due to the strong dispersive phase response that reduces the sensor’s dependence on the external environment. We also show that the bandwidth determination procedure of the resonance which is needed to characterize the sample losses is significantly simplified. The concept of phase sensing is shown by devising an experimental microstrip open stub resonator whose frequency response lies in the anomalous dispersion region. The dielectric characteristics of the samples placed on the stub are extracted from the resonant frequency and the slope of the phase response. We also demonstrate that the changes in moisture levels can also be detected by utilizing the phase sensing method. PMID:27346337

  15. Mobile Wireless Sensor Networks for Advanced Soil Sensing and Ecosystem Monitoring

    NASA Astrophysics Data System (ADS)

    Mollenhauer, Hannes; Schima, Robert; Remmler, Paul; Mollenhauer, Olaf; Hutschenreuther, Tino; Toepfer, Hannes; Dietrich, Peter; Bumberger, Jan

    2015-04-01

    For an adequate characterization of ecosystems it is necessary to detect individual processes with suitable monitoring strategies and methods. Due to the natural complexity of all environmental compartments, single point or temporally and spatially fixed measurements are mostly insufficient for an adequate representation. The application of mobile wireless sensor networks for soil and atmosphere sensing offers significant benefits, due to the simple adjustment of the sensor distribution, the sensor types and the sample rate (e.g. by using optimization approaches or event triggering modes) to the local test conditions. This can be essential for the monitoring of heterogeneous and dynamic environmental systems and processes. One significant advantage in the application of mobile ad-hoc wireless sensor networks is their self-organizing behavior. Thus, the network autonomously initializes and optimizes itself. Due to the localization via satellite a major reduction in installation and operation costs and time is generated. In addition, single point measurements with a sensor are significantly improved by measuring at several optimized points continuously. Since performing analog and digital signal processing and computation in the sensor nodes close to the sensors a significant reduction of the data to be transmitted can be achieved which leads to a better energy management of nodes. Furthermore, the miniaturization of the nodes and energy harvesting are current topics under investigation. First results of field measurements are given to present the potentials and limitations of this application in environmental science. In particular, collected in-situ data with numerous specific soil and atmosphere parameters per sensor node (more than 25) recorded over several days illustrates the high performance of this system for advanced soil sensing and soil-atmosphere interaction monitoring. Moreover, investigations of biotic and abiotic process interactions and optimization

  16. Sensor Needs for Advanced Life Support

    NASA Technical Reports Server (NTRS)

    Graf, John C.

    2000-01-01

    Sensors and feedback systems are critical to life support flight systems and life support systems research. New sensor capabilities can allow for new system architectures to be considered, and can facilitate dramatic improvements in system performance. This paper will describe three opportunities for biosensor researchers to develop sensors that will enable life support system improvements. The first opportunity relates to measuring physical, chemical, and biological parameters in the Space Station Water Processing System. Measuring pH, iodine, total organic carbon, microbiological activity, total dissolved solids, or conductivity with a safe, effective, stable, reliable microsensor could benefit the water processing system considerably. Of special interest is a sensor which can monitor biological contamination rapidly. The second opportunity relates to sensing microbiological contamination and water condensation on the surface of large inflatable structures. It is the goal of large inflatable structures used for habitation to take advantage of the large surface area of the structure and reject waste heat passively through the walls of the structure. Too much heat rejection leads to a cold spot with water condensation, and eventually microbiological contamination. A distributed sensor system that can measure temperature, humidity, and microbiological contamination across a large surface would benefit designers of large inflatable habitable structures. The third opportunity relates to sensing microbial bioreactors used for waste water processing and reuse. Microbiological bioreactors offer considerable advantages in weight and power compared to adsorption bed based systems when used for long periods of time. Managing and controlling bioreactors is greatly helped if distributed microsensors measured the biological populations continuously in many locations within the bioreactor. Nitrifying bacteria are of special interest to bioreactor designers, and any sensors that

  17. Advanced figure sensor operations and maintenance manual

    NASA Technical Reports Server (NTRS)

    Robertson, H. J.

    1972-01-01

    This manual contains procedures for installing, operating, and maintaining the optical figure sensor and its associated electronic controls. The optical figure sensor, a system of integrated components, comprises: (1) a phase measuring modified interferometer employing a single frequency 6328 A laser, and a Vidissector; (2) a two-axis automatic thermal compensation control mount; (3) a five degree of freedom manual adjustment stand; and (4) a control console. This instrument provides real time output data of optical figure errors for spherical mirrors, and is also capable of measuring aspherical mirrors if a null corrector is added.

  18. Calibration of non-contact ultrasound as an online sensor for wood characterization: Effects of temperature, moisture, and scanning direction

    NASA Astrophysics Data System (ADS)

    Vun, R. Y.; Hoover, K.; Janowiak, J.; Bhardwaj, M.

    2008-01-01

    Numerous handheld moisture meters are available for measuring moisture levels of wood and building materials for a vast range of quality control and moisture diagnosis applications. However, many methods currently available require physical contact of a probe with the test material to operate. The contact requirement of such devices has limited applications for these purposes. There is a tremendous demand for dynamic online quality assessment of in-process materials for moisture content (MC) measurements. In this paper, a non-destructive non-contact ultrasound technology was used to evaluate the effects of increasing temperature in two MC levels and of increasing MC in lumber. The results show that the ultrasonic absolute transmittance and velocity parameters are directly correlated very well (R2≥0.87) with temperature for the two moisture levels in wood. At constant temperature, however, the velocity is inversely correlated with MC. It was also found that the distribution of MC along the length is marginally insignificant to both ultrasonic measurements. The transmittance measurement along the orthogonal thickness direction is insignificant above the fiber saturation MC; similarly, the velocity measurement is marginally insignificant. The study concludes a positive correlation and a good fit for this technology to advance into the development of an automated device for determining wood moisture levels, which will in turn be used to control the dynamics of wood drying/sterilization processes. Further calibration research is recommended to ascertain the constraints and limitations of the technology to specific wood species and dimension.

  19. Advances in Thin Film Sensor Technologies for Engine Applications

    NASA Technical Reports Server (NTRS)

    Lei, Jih-Fen; Martin, Lisa C.; Will, Herbert A.

    1997-01-01

    Advanced thin film sensor techniques that can provide accurate surface strain and temperature measurements are being developed at NASA Lewis Research Center. These sensors are needed to provide minimally intrusive characterization of advanced materials (such as ceramics and composites) and structures (such as components for Space Shuttle Main Engine, High Speed Civil Transport, Advanced Subsonic Transports and General Aviation Aircraft) in hostile, high-temperature environments and for validation of design codes. This paper presents two advanced thin film sensor technologies: strain gauges and thermocouples. These sensors are sputter deposited directly onto the test articles and are only a few micrometers thick; the surface of the test article is not structurally altered and there is minimal disturbance of the gas flow over the surface. The strain gauges are palladium-13% chromium based and the thermocouples are platinum-13% rhodium vs. platinum. The fabrication techniques of these thin film sensors in a class 1000 cleanroom at the NASA Lewis Research Center are described. Their demonstration on a variety of engine materials, including superalloys, ceramics and advanced ceramic matrix composites, in several hostile, high-temperature test environments are discussed.

  20. Advances in Multi-Sensor Data Fusion: Algorithms and Applications

    PubMed Central

    Dong, Jiang; Zhuang, Dafang; Huang, Yaohuan; Fu, Jingying

    2009-01-01

    With the development of satellite and remote sensing techniques, more and more image data from airborne/satellite sensors have become available. Multi-sensor image fusion seeks to combine information from different images to obtain more inferences than can be derived from a single sensor. In image-based application fields, image fusion has emerged as a promising research area since the end of the last century. The paper presents an overview of recent advances in multi-sensor satellite image fusion. Firstly, the most popular existing fusion algorithms are introduced, with emphasis on their recent improvements. Advances in main applications fields in remote sensing, including object identification, classification, change detection and maneuvering targets tracking, are described. Both advantages and limitations of those applications are then discussed. Recommendations are addressed, including: (1) Improvements of fusion algorithms; (2) Development of “algorithm fusion” methods; (3) Establishment of an automatic quality assessment scheme. PMID:22408479

  1. Applications of fiber optic sensors in advanced engine controls

    NASA Astrophysics Data System (ADS)

    Nitka, Edward F., II

    1989-06-01

    Measured parameters, operating ranges, accuracy requirements, environmental constraints, and speed of response of fiber optic sensors are identified for three categories of engines. The three engine categories are: (1) current turbojet, turbofan, and turboprop engines; (2) next generation and turbofan engines to be built in the 1990s; and (3) advanced supersonic/hypersonic engines represented by ramjet, scramjet, and air-turbo-ramjet concepts. The key development and test efforts in engine control applications of fiber optic sensors are discussed.

  2. Advanced technology for space communications, tracking, and robotic sensors

    NASA Technical Reports Server (NTRS)

    Krishen, Kumar

    1989-01-01

    Technological advancements in tracking, communications, and robotic vision sensors are reviewed. The development of communications systems for multiple access, broadband, high data rate, and efficient operation is discussed. Consideration is given to the Tracking and Data Relay Satellite systems, GPS, and communications and tracking systems for the Space Shuttle and the Space Station. The use of television, laser, and microwave sensors for robotics and technology for autonomous rendezvous and docking operations are examined.

  3. Retrieving Atmospheric Temperature and Moisture Profiles from NPP CRIS/ATMS Sensors Using Crimss EDR Algorithm

    NASA Technical Reports Server (NTRS)

    Liu, X.; Kizer, S.; Barnet, C.; Dvakarla, M.; Zhou, D. K.; Larar, A. M.

    2012-01-01

    The Joint Polar Satellite System (JPSS) is a U.S. National Oceanic and Atmospheric Administration (NOAA) mission in collaboration with the U.S. National Aeronautical Space Administration (NASA) and international partners. The NPP Cross-track Infrared Microwave Sounding Suite (CrIMSS) consists of the infrared (IR) Crosstrack Infrared Sounder (CrIS) and the microwave (MW) Advanced Technology Microwave Sounder (ATMS). The CrIS instrument is hyperspectral interferometer, which measures high spectral and spatial resolution upwelling infrared radiances. The ATMS is a 22-channel radiometer similar to Advanced Microwave Sounding Units (AMSU) A and B. It measures top of atmosphere MW upwelling radiation and provides capability of sounding below clouds. The CrIMSS Environmental Data Record (EDR) algorithm provides three EDRs, namely the atmospheric vertical temperature, moisture and pressure profiles (AVTP, AVMP and AVPP, respectively), with the lower tropospheric AVTP and the AVMP being JPSS Key Performance Parameters (KPPs). The operational CrIMSS EDR an algorithm was originally designed to run on large IBM computers with dedicated data management subsystem (DMS). We have ported the operational code to simple Linux systems by replacing DMS with appropriate interfaces. We also changed the interface of the operational code so that we can read data from both the CrIMSS science code and the operational code and be able to compare lookup tables, parameter files, and output results. The detail of the CrIMSS EDR algorithm is described in reference [1]. We will present results of testing the CrIMSS EDR operational algorithm using proxy data generated from the Infrared Atmospheric Sounding Interferometer (IASI) satellite data and from the NPP CrIS/ATMS data.

  4. Monitoring soil moisture patterns in alpine meadows using ground sensor networks and remote sensing techniques

    NASA Astrophysics Data System (ADS)

    Bertoldi, Giacomo; Brenner, Johannes; Notarnicola, Claudia; Greifeneder, Felix; Nicolini, Irene; Della Chiesa, Stefano; Niedrist, Georg; Tappeiner, Ulrike

    2015-04-01

    Soil moisture content (SMC) is a key factor for numerous processes, including runoff generation, groundwater recharge, evapotranspiration, soil respiration, and biological productivity. Understanding the controls on the spatial and temporal variability of SMC in mountain catchments is an essential step towards improving quantitative predictions of catchment hydrological processes and related ecosystem services. The interacting influences of precipitation, soil properties, vegetation, and topography on SMC and the influence of SMC patterns on runoff generation processes have been extensively investigated (Vereecken et al., 2014). However, in mountain areas, obtaining reliable SMC estimations is still challenging, because of the high variability in topography, soil and vegetation properties. In the last few years, there has been an increasing interest in the estimation of surface SMC at local scales. On the one hand, low cost wireless sensor networks provide high-resolution SMC time series. On the other hand, active remote sensing microwave techniques, such as Synthetic Aperture Radars (SARs), show promising results (Bertoldi et al. 2014). As these data provide continuous coverage of large spatial extents with high spatial resolution (10-20 m), they are particularly in demand for mountain areas. However, there are still limitations related to the fact that the SAR signal can penetrate only a few centimeters in the soil. Moreover, the signal is strongly influenced by vegetation, surface roughness and topography. In this contribution, we analyse the spatial and temporal dynamics of surface and root-zone SMC (2.5 - 5 - 25 cm depth) of alpine meadows and pastures in the Long Term Ecological Research (LTER) Area Mazia Valley (South Tyrol - Italy) with different techniques: (I) a network of 18 stations; (II) field campaigns with mobile ground sensors; (III) 20-m resolution RADARSAT2 SAR images; (IV) numerical simulations using the GEOtop hydrological model (Rigon et al

  5. Advanced thermal-sensor-system development via shuttle sortie missions

    SciTech Connect

    Angelo, J.A. Jr.; Ginsberg, I.W.

    1981-01-01

    The use of the Space Shuttle in various sortie mission modes to evaluate advanced thermal sensor system concepts, prior to a design commitment for automated spacecraft application, is described. Selected terrestrial energy sources of civilian and/or military interest are examined with respect to: (1) thermal source location and characterization and (2) temperature and emissivity measurements. Of particular interest is the application of on-orbit sensor testing to demonstrate the location and characterization of potential geothermal energy resources. The role of the payload specialist in thermal source location, sensor operation and real time evaluation of mission performance is discussed.

  6. Field test of a multi-frequency electromagnetic induction sensor for soil moisture monitoring in southern Italy test sites

    NASA Astrophysics Data System (ADS)

    Calamita, G.; Perrone, A.; Brocca, L.; Onorati, B.; Manfreda, S.

    2015-10-01

    Soil moisture is a variable of paramount importance for a number of natural processes and requires the capacity to be routinely measured at different spatial and temporal scales (e.g., hillslope and/or small catchment scale). The electromagnetic induction (EMI) method is one of the geophysical techniques potentially useful in this regard. Indeed, it does not require contact with the ground, it allows a relatively fast survey of hillslope, it gives information related to soil depth greater than few centimetres and it can also be used in wooded areas. In this study, apparent electrical conductivity (ECa) and soil moisture (SM) measurements were jointly carried out by using a multi-frequency EMI sensor (GEM-300) and Time Domain Reflectometry (TDR) probes, respectively. The aim was to retrieve SM variations at the hillslope scale over four sites, characterized by different land-soil units, located in a small mountainous catchment in southern Italy. Repeated measurements of ECa carried out over a fixed point showed that the signal variability of the GEM-300 sensor (Std. Err. ∼[0.02-0.1 mS/m]) was negligible. The correlation estimated between point ECa and SM, measured with both portable and buried TDR probes, varied between 0.24 and 0.58, depending on the site considered. In order to reduce the effect of small-scale variability, a spatial smoothing filter was applied which allowed the estimation of linear relationships with higher coefficient of correlation (r ∼ 0.46-0.8). The accuracy obtained in the estimation of the temporal trend of the soil moisture spatial averages was in the range ∼4.5-7.8% v/v and up to the ∼70% of the point soil moisture variance was explained by the ECa signal. The obtained results highlighted the potential of EMI to provide, in a short time, sufficiently accurate estimate of soil moisture over large areas that are highly needed for hydrological and remote sensing applications.

  7. Advanced Sensors Boost Optical Communication, Imaging

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Brooklyn, New York-based Amplification Technologies Inc. (ATI), employed Phase I and II SBIR funding from NASA s Jet Propulsion Laboratory to forward the company's solid-state photomultiplier technology. Under the SBIR, ATI developed a small, energy-efficient, extremely high-gain sensor capable of detecting light down to single photons in the near infrared wavelength range. The company has commercialized this technology in the form of its NIRDAPD photomultiplier, ideal for use in free space optical communications, lidar and ladar, night vision goggles, and other light sensing applications.

  8. Evaluation of several calibration procedures for a portable soil moisture sensor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The calibration and validation of remotely sensed soil moisture products relies upon an accurate source of ground truth data. The primary method of providing this ground truth is to conduct intensive field campaigns with manual surface soil moisture sampling measurements, which utilize gravimetric s...

  9. Capacitance Sensors for Nondestructive Moisture Determination in Agricultural and Bio-fuel materials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Moisture content of wood chips, pellets, switch grass powders, and similar organic bio-fuel materials is an important property to be known to determine their utility and energy efficiency at various stages of their processing and storage. Several moisture measuring instruments are available in the m...

  10. NONDESTRUCTIVE MEASUREMENT OF MOISTURE CONTENT USING A PARALLEL-PLATE CAPACITANCE SENSOR FOR GRAIN AND NUTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A simple, low cost instrument that measures impedance and phase angle was used along with a parallel-plate capacitance system to estimate the moisture content (MC) of in-shell peanuts and yellow field corn. Moisture content of the field crops is important and is measured at various stages of their ...

  11. Underwater Adhesives Retrofit Pipelines with Advanced Sensors

    NASA Technical Reports Server (NTRS)

    2015-01-01

    Houston-based Astro Technology Inc. used a partnership with Johnson Space Center to pioneer an advanced fiber-optic monitoring system for offshore oil pipelines. The company's underwater adhesives allow it to retrofit older deepwater systems in order to measure pressure, temperature, strain, and flow properties, giving energy companies crucial data in real time and significantly decreasing the risk of a catastrophe.

  12. Automated sensor networks to advance ocean science

    NASA Astrophysics Data System (ADS)

    Schofield, O.; Orcutt, J. A.; Arrott, M.; Vernon, F. L.; Peach, C. L.; Meisinger, M.; Krueger, I.; Kleinert, J.; Chao, Y.; Chien, S.; Thompson, D. R.; Chave, A. D.; Balasuriya, A.

    2010-12-01

    The National Science Foundation has funded the Ocean Observatories Initiative (OOI), which over the next five years will deploy infrastructure to expand scientist’s ability to remotely study the ocean. The deployed infrastructure will be linked by a robust cyberinfrastructure (CI) that will integrate marine observatories into a coherent system-of-systems. OOI is committed to engaging the ocean sciences community during the construction pahse. For the CI, this is being enabled by using a “spiral design strategy” allowing for input throughout the construction phase. In Fall 2009, the OOI CI development team used an existing ocean observing network in the Mid-Atlantic Bight (MAB) to test OOI CI software. The objective of this CI test was to aggregate data from ships, autonomous underwater vehicles (AUVs), shore-based radars, and satellites and make it available to five different data-assimilating ocean forecast models. Scientists used these multi-model forecasts to automate future glider missions in order to demonstrate the feasibility of two-way interactivity between the sensor web and predictive models. The CI software coordinated and prioritized the shared resources that allowed for the semi-automated reconfiguration of assett-tasking, and thus enabled an autonomous execution of observation plans for the fixed and mobile observation platforms. Efforts were coordinated through a web portal that provided an access point for the observational data and model forecasts. Researchers could use the CI software in tandem with the web data portal to assess the performance of individual numerical model results, or multi-model ensembles, through real-time comparisons with satellite, shore-based radar, and in situ robotic measurements. The resulting sensor net will enable a new means to explore and study the world’s oceans by providing scientists a responsive network in the world’s oceans that can be accessed via any wireless network.

  13. Sensors, controls, and man-machine interface for advanced teleoperation

    NASA Technical Reports Server (NTRS)

    Bejczy, A. K.

    1980-01-01

    Some advances are reviewed which have been made in teleoperator (i.e., mechanical activities performed by mechanical devices at a remote site under remote control) technology through introduction of sensors, computers, automation, and new man-machine interface devices and techniques for remote manipulator control. The state of the art is summarized and some basic problems and challenging developments are examined.

  14. Development of sensors for ceramic components in advanced propulsion systems

    NASA Technical Reports Server (NTRS)

    Atkinson, William H.; Cyr, M. A.; Strange, R. R.

    1994-01-01

    The 'Development of Sensors for Ceramics Components in Advanced Propulsion Systems' program was divided into two phases. The objectives of Phase 1 were to analyze, evaluate and recommend sensor concepts for the measurement of surface temperature, strain and heat flux on ceramic components for advanced propulsion systems. The results of this effort were previously published in NASA CR-182111. As a result of Phase 1, three approaches were recommended for further development: pyrometry, thin-film sensors, and thermographic phosphors. The objectives of Phase 2 were to fabricate and conduct laboratory demonstration tests of these systems. A summary report of the Phase 2 effort, together with conclusions and recommendations for each of the categories evaluated, has been submitted to NASA. Emittance tests were performed on six materials furnished by NASA Lewis Research Center. Measurements were made of various surfaces at high temperature using a Thermogage emissometer. This report describes the emittance test program and presents a summary of the results.

  15. Latest Development in Advanced Sensors at Kennedy Space Center (KSC)

    NASA Technical Reports Server (NTRS)

    Perotti, Jose M.; Eckhoff, Anthony J.; Voska, N. (Technical Monitor)

    2002-01-01

    Inexpensive space transportation system must be developed in order to make spaceflight more affordable. To achieve this goal, there is a need to develop inexpensive smart sensors to allow autonomous checking of the health of the vehicle and associated ground support equipment, warn technicians or operators of an impending problem and facilitate rapid vehicle pre-launch operations. The Transducers and Data Acquisition group at Kennedy Space Center has initiated an effort to study, research, develop and prototype inexpensive smart sensors to accomplish these goals. Several technological challenges are being investigated and integrated in this project multi-discipline sensors; self-calibration, health self-diagnosis capabilities embedded in sensors; advanced data acquisition systems with failure prediction algorithms and failure correction (self-healing) capabilities.

  16. Advanced haptic sensor for measuring human skin conditions

    NASA Astrophysics Data System (ADS)

    Tsuchimi, Daisuke; Okuyama, Takeshi; Tanaka, Mami

    2009-12-01

    This paper is concerned with the development of a tactile sensor using PVDF (Polyvinylidene Fluoride) film as a sensory receptor of the sensor to evaluate softness, smoothness, and stickiness of human skin. Tactile sense is the most important sense in the sensation receptor of the human body along with eyesight, and we can examine skin condition quickly using these sense. But, its subjectivity and ambiguity make it difficult to quantify skin conditions. Therefore, development of measurement device which can evaluate skin conditions easily and objectively is demanded by dermatologists, cosmetic industries, and so on. In this paper, an advanced haptic sensor system that can measure multiple information of skin condition in various parts of human body is developed. The applications of the sensor system to evaluate softness, smoothness, and stickiness of skin are investigated through two experiments.

  17. Advanced haptic sensor for measuring human skin conditions

    NASA Astrophysics Data System (ADS)

    Tsuchimi, Daisuke; Okuyama, Takeshi; Tanaka, Mami

    2010-01-01

    This paper is concerned with the development of a tactile sensor using PVDF (Polyvinylidene Fluoride) film as a sensory receptor of the sensor to evaluate softness, smoothness, and stickiness of human skin. Tactile sense is the most important sense in the sensation receptor of the human body along with eyesight, and we can examine skin condition quickly using these sense. But, its subjectivity and ambiguity make it difficult to quantify skin conditions. Therefore, development of measurement device which can evaluate skin conditions easily and objectively is demanded by dermatologists, cosmetic industries, and so on. In this paper, an advanced haptic sensor system that can measure multiple information of skin condition in various parts of human body is developed. The applications of the sensor system to evaluate softness, smoothness, and stickiness of skin are investigated through two experiments.

  18. Simulation and ground testing with the Advanced Video Guidance Sensor

    NASA Technical Reports Server (NTRS)

    Howard, Richard T.; Johnston, Albert S.; Bryan, Thomas C.; Book, Michael L.

    2005-01-01

    The Advanced Video Guidance Sensor (AVGS), an active sensor system that provides near-range 6-degree-of-freedom sensor data, has been developed as part of an automatic rendezvous and docking system for the Demonstration of Autonomous Rendezvous Technology (DART). The sensor determines the relative positions and attitudes between the active sensor and the passive target at ranges up to 300 meters. The AVGS uses laser diodes to illuminate retro-reflectors in the target, a solid-state imager to detect the light returned from the target, and image capture electronics and a digital signal processor to convert the video information into the relative positions and attitudes. The development of the sensor, through initial prototypes, final prototypes, and three flight units, has required a great deal of testing at every phase, and the different types of testing, their effectiveness, and their results, are presented in this paper, focusing on the testing of the flight units. Testing has improved the sensor's performance.

  19. Design and performance of a wireless sensor network for catchment-scale snow and soil moisture measurements

    NASA Astrophysics Data System (ADS)

    Kerkez, Branko; Glaser, Steven D.; Bales, Roger C.; Meadows, Matthew W.

    2012-09-01

    A wireless sensor network (WSN) was deployed as part of a water balance instrument cluster across a forested 1 km2headwater catchment in the southern Sierra Nevada of California. The network, which integrates readings from over 300 sensors, provides spatially representative measurements of snow depth, solar radiation, relative humidity, soil moisture, and matric potential. The ability of this densely instrumented watershed to capture catchment-scale snow depth and soil moisture distributions is investigated through comparison with three comprehensive gridded surveys and 1 day of detailed lidar snow data. Statistical analysis shows that the network effectively characterized catchment-wide distributions of snow depth, while offering a cost-effective, reliable, and energy-efficient means for collecting distributed data in real time. A temporal analysis of snow depth variability reveals that canopy cover is the major explanatory variable of snow depth and that under-canopy measurements persistently show higher variability compared to those in open terrain. An analysis of soil moisture shows lower variability at deeper soil depth and a correlation between mean soil moisture and variability for shallow soils. A three-phase design procedure was used to optimize the WSN deployment. First, as off-the-shelf performance of current WSN platforms for large-scale, long-term deployments cannot be guaranteed, statistics from a prototype deployment were analyzed. Two indicators of network performance, the packet delivery ratio and received signal strength indicator, showed that for our site conditions, a conservative 50 m node-to-node spacing would ensure low-power, reliable, and robust network communications. Second, results from the prototype were used to refine hardware specifications and to guide the layout of the full 57-node wireless network. Of these nodes, 23 were used actively for sensing, while the remaining 34 nodes were used as signal repeaters to ensure proper spatial

  20. Remotely-Sensed Soil Moisture for Agricultural Decision Support: An Integration of National-Scale Hydroclimatic Classification and Ground-Based Sensors

    NASA Astrophysics Data System (ADS)

    Coopersmith, E. J.; Minsker, B. S.; Sivapalan, M.

    2013-12-01

    Agricultural managers employ soil moisture estimates to inform irrigation and drainage planning as well as the timing of entry for heavier equipment, but ground-based soil moisture sensors are often unavailable for the location in question. Data-driven models of soil moisture often require an array of inputs that are difficult to obtain beyond the scope of a research study and/or recalibration at each location for which predictions are needed. A hydroclimatic classification system was previously constructed from over 400 well-gauged catchments in the MOPEX database using four simple hydrologic and climatic indicators. These catchments are subsequently grouped in twenty-four clusters. A simple, lumped soil moisture model, receiving only public precipitation data as an input, is calibrated at the fifteen sites with ground-based soil moisture sensors, producing correlations 0.9 with respect to observed soil moisture values. The fifteen sites are also assessed in terms of textural and taxonomic properties. The model is then shown to be valid at other locations that are hydroclimatically and edaphically similar to the calibration site. By integrating this simple soil moisture algorithm with an existing system for hydroclimatic classification and publicly-available edaphic information (USDA's soil web, e.g.), a single set of calibrated parameters can facilitate remotely-sensed soil moisture estimates for agronomic decision-support at any site with similar edaphic and hydroclimatic properties.

  1. The Advanced Technology Microwave Sounder (ATMS): A New Operational Sensor Series

    NASA Technical Reports Server (NTRS)

    Kim, Edward; Lyu, Cheng-H Joseph; Leslie, R. Vince; Baker, Neal; Mo, Tsan; Sun, Ninghai; Bi, Li; Anderson, Mike; Landrum, Mike; DeAmici, Giovanni; Gu, Degui; Foo, Alex; Ibrahim, Wael; Robinson, Kris; Chidester, Lynn; Shiue, James

    2012-01-01

    ATMS is a new satellite microwave sounding sensor designed to provide operational weather agencies with atmospheric temperature and moisture profile information for global weather forecasting and climate applications. ATMS will continue the microwave sounding capabilities first provided by its predecessors, the Microwave Sounding Unit (MSU) and Advanced Microwave Sounding Unit (AMSU). The first ATMS was launched October 28, 2011 on board the Suomi National Polar-orbiting Partnership (S-NPP) satellite. Microwave soundings by themselves are the highest-impact input data used by Numerical Weather Prediction (NWP) models; and ATMS, when combined with the Cross-track Infrared Sounder (CrIS), forms the Cross-track Infrared and Microwave Sounding Suite (CrIMSS). The microwave soundings help meet NWP sounding requirements under cloudy sky conditions and provide key profile information near the surface

  2. Effects of moisture profiles and laminate configuration on the hygro stress in advanced composites

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Lark, R. F.; Sinclair, J. H.

    1978-01-01

    A theoretical investigation was performed using a recently developed integrated theory for predicting the hygrothermomechanical response to investigate the effects of three different moisture profiles on the ply hygro stresses in angleplied laminates. The moisture profiles were linear, parabolic and hyperbolic varying from 1 percent at the exposed ply to '0' percent in the protected ply. The angleplied laminates were of two generic configurations. The results obtained are summarized graphically to illustrate the effects of both moisture profile and laminate configuration.

  3. Advanced sensors for spaceborne measurements of the earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Hinkley, E. D.

    1982-01-01

    Concepts involved in remote sensing from space are reviewed, together with performance requirements of proposed and planned equipment. Attention is focused on measurements of the troposphere, particularly meteorological variables and chemical species. The principles of absorption, using either passive or active sensors, emission detection, fluorescence measurements, and EM radiation scattering are outlined. The proposed NASA Windsat, using a CO2 laser from the Orbiter or from an 800 km orbit spacecraft to measure low-level wind speeds is described, as are the uses of the AMTS atmospheric sounder instrument for IR atmospheric temperature sensing and a 20-channel microwave radiometer to detect moisture profiles in the water vapor bands. Additionally, a microwave pressure sounder to detect backscattered signals at 60 GHz is outlined, along with lidar pressure and wind speed measurement methods.

  4. Estimation of moisture and oil content of in-shell nuts with a capacitance sensor using discrete wavelet analysis

    NASA Astrophysics Data System (ADS)

    Kandala, Chari V.; Sundaram, Jaya; Govindarajan, K. N.; Butts, Chris L.; Subbiah, Jeyam

    2009-03-01

    Moisture and oil contents are important quality factors often measured and monitored in the processing and storage of food products such as corn and peanuts. For estimating these parameters for peanuts nondestructively a parallel-plate capacitance sensor was used in conjunction with an impedance analyzer. Impedance, phase angle and dissipation factor were measured for the parallel-plate system, holding the in-shell peanut samples between its plates, at frequencies ranging between 1MHz and 30 MHz in intervals of 0.5 MHz. The acquired signals were analyzed with discrete wavelet analysis. The signals were decomposed to 6 levels using Daubechies mother wavelet. The decomposition coefficients of the sixth level were passed onto a stepwise variable selection routine to select significant variables. A linear regression was developed using only the significant variables to predict the moisture and oil content of peanut pods (inshell peanuts) from the impedance measurements. The wavelet analysis yielded similar R2 values with fewer variables as compared to multiple linear and partial least squares regressions. The estimated values were found to be in good agreement with the standard values for the samples tested. Ability to estimate the moisture and oil contents in peanuts without shelling them will be of considerable help to the peanut industry.

  5. Field-scale moisture estimates using COSMOS sensors: A validation study with temporary networks and Leaf-Area-Indices

    NASA Astrophysics Data System (ADS)

    Coopersmith, Evan J.; Cosh, Michael H.; Daughtry, Craig S. T.

    2014-11-01

    The COsmic-ray Soil Moisture Observing System (COSMOS) is a new and innovative method for estimating surface and near-surface soil moisture at large (∼700 m) scales. This system accounts for liquid water within its measurement volume. Many of the sites used in the early validation of the system had low and stable vegetation water content. It is necessary to perform validation of COSMOS in a landscape with a significant change in vegetation water content to estimate its impact on the COSMOS estimate, and potentially, correct the estimate to account for the dynamic vegetation cover. A COSMOS station was installed in Beltsville, MD in the spring of 2012, within the domain of a long-term experimental station on USDA property. This station has a large array of soil moisture sensors in profile across the field, which is approximately 700 m in diameter. Frequent estimates of Leaf Area Index (LAI) were made throughout the 2012 and 2013 growing seasons (May through September). COSMOS readings, with a simple linear adjustment, were able to produce estimates of area-weighted averages of the existing in situ network with root-mean-squared-errors (RMSE) of soil-water content well below 0.04 m3/m3 and with additional modeling to account for Leaf Area Index (LAI) values, RMSE values less than 0.03 m3/m3 were achieved.

  6. Next Generation Advanced Video Guidance Sensor: Low Risk Rendezvous and Docking Sensor

    NASA Technical Reports Server (NTRS)

    Lee, Jimmy; Carrington, Connie; Spencer, Susan; Bryan, Thomas; Howard, Ricky T.; Johnson, Jimmie

    2008-01-01

    The Next Generation Advanced Video Guidance Sensor (NGAVGS) is being built and tested at MSFC. This paper provides an overview of current work on the NGAVGS, a summary of the video guidance heritage, and the AVGS performance on the Orbital Express mission. This paper also provides a discussion of applications to ISS cargo delivery vehicles, CEV, and future lunar applications.

  7. Development of Sensors for Ceramic Components in Advanced Propulsion Systems. Phase 2; Temperature Sensor Systems Evaluation

    NASA Technical Reports Server (NTRS)

    Atkinson, W. H.; Cyr, M. A.; Strange, R. R.

    1994-01-01

    The 'development of sensors for ceramic components in advanced propulsion systems' program is divided into two phases. The objectives of Phase 1 were to analyze, evaluate and recommend sensor concepts for the measurement of surface temperature, strain and heat flux on ceramic components for advanced propulsion systems. The results of this effort were previously published in NASA CR-182111. As a result of Phase 1, three approaches were recommended for further development: pyrometry, thin-film sensors, and thermographic phosphors. The objective of Phase 2 were to fabricate and conduct laboratory demonstration tests of these systems. Six materials, mutually agreed upon by NASA and Pratt & Whitney, were investigated under this program. This report summarizes the Phase 2 effort and provides conclusions and recommendations for each of the categories evaluated.

  8. Advanced optical position sensors for magnetically suspended wind tunnel models

    NASA Technical Reports Server (NTRS)

    Lafleur, S.

    1985-01-01

    A major concern to aerodynamicists has been the corruption of wind tunnel test data by model support structures, such as stings or struts. A technique for magnetically suspending wind tunnel models was considered by Tournier and Laurenceau (1957) in order to overcome this problem. This technique is now implemented with the aid of a Large Magnetic Suspension and Balance System (LMSBS) and advanced position sensors for measuring model attitude and position within the test section. Two different optical position sensors are discussed, taking into account a device based on the use of linear CCD arrays, and a device utilizing area CID cameras. Current techniques in image processing have been employed to develop target tracking algorithms capable of subpixel resolution for the sensors. The algorithms are discussed in detail, and some preliminary test results are reported.

  9. High resolution modelling of soil moisture patterns with ParFlow-CLM: Comparison with sensor network data

    NASA Astrophysics Data System (ADS)

    Gebler, Sebastian; Hendricks-Franssen, Harrie-Jan; Kollet, Stefan; Qu, Wei; Vereecken, Harry

    2015-04-01

    Soil hydrological processes play an important role for heat, water and matter exchanges in the soil-vegetation-atmosphere continuum. The prediction of the spatial and temporal variability of soil moisture and discharge and evaporative fluxes with land surface models on small scales and at high resolutions is still a challenge. This work focuses on the comparison of soil moisture measured by a sensor network (179 sensors installed in an area of size 31 ha) and modelled with a variably saturated groundwater model (ParFlow) coupled to a land surface model (Common Land Model (CLM, version 2.0)) using different levels of model complexity and spatial resolution. ParFlow simulates variably saturated flow fully coupled with overland flow on large scales and at high spatial resolutions. The Common Land Model (CLM) is embedded as a module in ParFlow, the soil column of CLM is replaced by ParFlow to improve the representation of lateral subsurface flow, groundwater and overland flow. In this study, we investigated the impact of different parameterization schemes of a ParFlow-CLM model set-up for a managed 31 ha grassland TERENO head-water catchment in the Eifel (Germany). Therefore, model runs with 1 x 1 m and 10 x 10 m lateral resolution, 0.05 m vertical resolution, and different complexity levels regarding subsurface soil hydraulic parameters are conducted. For each model complexity level (completely homogeneous; homogeneous parameters for different soil horizons; different parameters for each soil unit and soil horizon; heterogeneous stochastic realisations), we vary saturated hydraulic conductivity and porosity on the basis of measurements. The model performance is then evaluated using data of the SoilNet wireless sensor network, discharge measurements, and evapotranspiration data recorded by lysimeters and eddy covariance stations. The majority of simulations capture the temporal variable soil moisture at an acceptable level. However, spatial variability of soil water

  10. Harsh environment sensor development for advanced energy systems

    NASA Astrophysics Data System (ADS)

    Romanosky, Robert R.; Maley, Susan M.

    2013-05-01

    Highly efficient, low emission power systems have extreme conditions of high temperature, high pressure, and corrosivity that require monitoring. Sensing in these harsh environments can provide key information that directly impacts process control and system reliability. To achieve the goals and demands of clean energy, the conditions under which fossil fuels are converted into heat and power are harsh compared to traditional combustion/steam cycles. Temperatures can extend as high as 1600 Celsius (°C) in certain systems and pressures can reach as high as 5000 pounds per square inch (psi)/340 atmospheres (atm). The lack of suitable measurement technology serves as a driver for the innovations in harsh environment sensor development. Two major considerations in the development of harsh environments sensors are the materials used for sensing and the design of the sensing device. This paper will highlight the U.S. Department of Energy's, Office of Fossil Energy and National Energy Technology Laboratory's Program in advanced sensing concepts that are aimed at addressing the technology needs and drivers through the development of new sensor materials and designs capable of withstanding harsh environment conditions. Recent developments with harsh environment sensors will be highlighted and future directions towards in advanced sensing will be introduced.

  11. Advanced exterior sensor project : final report, September 2004.

    SciTech Connect

    Ashby, M. Rodema

    2004-12-01

    This report (1) summarizes the overall design of the Advanced Exterior Sensor (AES) system to include detailed descriptions of system components, (2) describes the work accomplished throughout FY04 to evaluate the current health of the original prototype and to return it to operation, (3) describes the status of the AES and the AES project as of September 2004, and (4) details activities planned to complete modernization of the system to include development and testing of the second-generation AES prototype.

  12. Design and performance of a capicitor sensor and impedance analyzer for nondestructive moisture content detemination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper describes a method to determine the moisture content of in-shell peanuts with a parallel-plate electrode system fitted inside a cylinder by using impedance measurements made on the system. Two parallel-plate electrodes were mounted inside a cylinder, made of acrylic material, and the spac...

  13. Survey of L Band Tower and Airborne Sensor Systems Relevant to Upcoming Soil Moisture Missions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Basic research on the physics of microwave remote sensing of soil moisture has been conducted for almost thirty years using ground-based (tower- or truck-mounted) microwave instruments at L band frequencies. Early small point-scale studies were aimed at improved understanding and verification of mi...

  14. Capacitance sensors for the nondestructive measurement of moisture content in in-shell peanuts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Moisture content (mc) in peanuts is measured at various stages of their processing and storage in the peanut industry. An instrument was developed earlier that would measure the capacitance and phase angle of a small sample of peanuts held between two circular parallel-plates at two frequencies 1 a...

  15. Comparison of remote sensors for soil moisture and other hydrologic studies

    NASA Technical Reports Server (NTRS)

    Wiesnet, D. R.

    1972-01-01

    Progress in lake temperature and soil moisture remote sensing during 1971. The use of satellite data and imagery for improved flood and low flow forecasts, improved water level and ice reports for the Great Lakes, and better and faster coastal zone storm damage assessment is considered.

  16. Flight evaluation of advanced third-generation midwave infrared sensor

    NASA Astrophysics Data System (ADS)

    Shen, Chyau N.; Donn, Matthew

    1998-08-01

    In FY-97 the Counter Drug Optical Upgrade (CDOU) demonstration program was initiated by the Program Executive Office for Counter Drug to increase the detection and classification ranges of P-3 counter drug aircraft by using advanced staring infrared sensors. The demonstration hardware is a `pin-for-pin' replacement of the AAS-36 Infrared Detection Set (IRDS) located under the nose radome of a P-3 aircraft. The hardware consists of a 3rd generation mid-wave infrared (MWIR) sensor integrated into a three axis-stabilized turret. The sensor, when installed on the P- 3, has a hemispheric field of regard and analysis has shown it will be capable of detecting and classifying Suspected Drug Trafficking Aircraft and Vessels at ranges several factors over the current IRDS. This paper will discuss the CDOU system and it's lab, ground, and flight evaluation results. Test targets included target templates, range targets, dedicated target boats, and targets of opportunity at the Naval Air Warfare Center Aircraft Division and at operational test sites. The objectives of these tests were to: (1) Validate the integration concept of the CDOU package into the P-3 aircraft. (2) Validate the end-to-end functionality of the system, including sensor/turret controls and recording of imagery during flight. (3) Evaluate the system sensitivity and resolution on a set of verified resolution targets templates. (4) Validate the ability of the 3rd generation MWIR sensor to detect and classify targets at a significantly increased range.

  17. Comparison of Riparian Evapotranspiration Estimated Using Raman LIDAR and Water Balance Based Estimates from a Soil Moisture Sensor Network

    NASA Astrophysics Data System (ADS)

    Solis, J. A.; Rajaram, H.; Whittemore, D. O.; Butler, J. J.; Eichinger, W. E.; Reboulet, E. C.

    2013-12-01

    Riparian evapotranspiration (RET) is an important component of basin-wide evapotranspiration (ET), especially in subhumid to semi-arid regions, with significant impacts on water management and conservation. A common method of measuring ET is using the eddy correlation technique. However, since most riparian zones are narrow, eddy correlation techniques are not applicable because of limited fetch distance. Techniques based on surface-subsurface water balance are applicable in these situations, but their accuracy is not well constrained. In this study, we estimated RET within a 100 meter long and 40 meter wide riparian zone along Rock Creek in the Whitewater Basin in central Kansas using a water balance approach and Raman LIDAR measurements. A total of six soil moisture profiles (with six soil moisture sensors in each profile) and water-table measurements were used to estimate subsurface water storage (total soil moisture, TSM). The Los Alamos National Laboratory (LANL)-University of Iowa (UI) Raman LIDAR was used to measure the water vapor concentrations in three dimensions where the Monin-Obukhov similarity theory was used to obtain the spatially resolved fluxes. The LIDAR system included a 1.064 micron Nd:YAG laser with a Cassagrain telescope with a laser pulse of 50Hz with 25mJ of energy per pulse. Estimates of RET obtained from TSM changes were compared to LIDAR estimates obtained from three-dimensional water vapor concentrations of the atmosphere directly above and downwind of the riparian vegetation. The LIDAR measurements help to validate the TSM based estimates of RET and constrain their accuracy. RET estimates obtained from TSM changes in individual soil moisture profiles exhibited a large variability (up to a factor 8). This variability results from the highly heterogeneous soils in the vadose zone (2-3 m thick), where soil moisture (rather than groundwater) is the major source of water for riparian vegetation. Variable vegetation density and species also

  18. Data assimilation with in situ soil moisture observations: what spatial configuration of the sensor network should be considered?

    NASA Astrophysics Data System (ADS)

    De Vleeschouwer, Niels; Verhoest, Niko E. C.; Pauwels, Valentijn R. N.

    2016-04-01

    Continuously monitoring soil moisture in a permanent in situ network can yield an interesting observation product for hydrological data assimilation. Those in situ observations can be characterised by some major advantages such as a fine temporal resolution, a large vertical extent, the small impact of land cover on the observation error, etc. Because of the typical small integration volume of in situ measurements and the often large spacing between monitoring locations, only a small part of the modelling domain can be directly observed. Therefore a first important question to answer is whether spatially sparse in-situ soil moisture observations contain a sufficient data representativeness to successfully update the largely unobserved spatial extent of a distributed hydrological model. Furthermore, the spatial configuration of the sensors remains unaltered through time. Consequently it is interesting to assess the sensitivity of the spatial configuration of the sensors regarding the data assimilation performance. This allows for answering a second question: is it possible to reduce the number of sensors by optimising the design of the in situ network whilst maintaining the same level of assimilation performance? To bring added value in practice, one should be able to identify optimal network configurations using prior available model input data and/or open loop statistics, i.e. statistics derived from a model run without data assimilation. In this study the meso-scale catchment of the Bellebeek (±100 km²) in Belgium is modelled. The above-mentioned questions are addressed by means of a synthetic data assimilation framework using the ensemble Kalman filter. It can be concluded that the network configuration can indeed have a significant influence on the assimilation performance. Furthermore, preliminary results indicate that certain open loop statistics can be used as a network performance predictor. More in particular, it was examined whether the information

  19. Advances in biologically inspired on/near sensor processing

    NASA Astrophysics Data System (ADS)

    McCarley, Paul L.

    1999-07-01

    As electro-optic sensors increase in size and frame rate, the data transfer and digital processing resource requirements also increase. In many missions, the spatial area of interest is but a small fraction of the available field of view. Choosing the right region of interest, however, is a challenge and still requires an enormous amount of downstream digital processing resources. In order to filter this ever-increasing amount of data, we look at how nature solves the problem. The Advanced Guidance Division of the Munitions Directorate, Air Force Research Laboratory at Elgin AFB, Florida, has been pursuing research in the are of advanced sensor and image processing concepts based on biologically inspired sensory information processing. A summary of two 'neuromorphic' processing efforts will be presented along with a seeker system concept utilizing this innovative technology. The Neuroseek program is developing a 256 X 256 2-color dual band IRFPA coupled to an optimized silicon CMOS read-out and processing integrated circuit that provides simultaneous full-frame imaging in MWIR/LWIR wavebands along with built-in biologically inspired sensor image processing functions. Concepts and requirements for future such efforts will also be discussed.

  20. Advances in downscaling soil moisture for use in drought and flood assessments: Implications for data from the Soil Moisture Active and Passive (SMAP) Mission

    NASA Astrophysics Data System (ADS)

    Lakshmi, V.; Fang, B.; Narayan, U.

    2015-12-01

    Hydrological hazards, namely droughts and floods are dependent on the deficit and excess of soil moisture. With the launch of the Soil Moisture Active and Passive Mission (SMAP) in January 2015 we will have twice a day global observations of soil moisture. However the spatial resolution of soil moisture retrieved from the SMAP radiometer is 10s of km and the SMAP radar will provide backscatter observations 100m-1km. High spatial resolution of soil moisture helps to monitor floods and droughts in a spatially distributed fashion. The current focus is finding the best way to obtain high spatial resolution soil moisture using the radar and radiometer observations. In this presentation we will deal with downscaling by couple of methods - (a) Use of the thermal inertia relation between soil moisture and surface temperature modulated by vegetation (b) Relationship between soil moisture and evaporation (c) Change detection using high spatial resolution active radar data.

  1. High temperature, harsh environment sensors for advanced power generation systems

    NASA Astrophysics Data System (ADS)

    Ohodnicki, P. R.; Credle, S.; Buric, M.; Lewis, R.; Seachman, S.

    2015-05-01

    One mission of the Crosscutting Technology Research program at the National Energy Technology Laboratory is to develop a suite of sensors and controls technologies that will ultimately increase efficiencies of existing fossil-fuel fired power plants and enable a new generation of more efficient and lower emission power generation technologies. The program seeks to accomplish this mission through soliciting, managing, and monitoring a broad range of projects both internal and external to the laboratory which span sensor material and device development, energy harvesting and wireless telemetry methodologies, and advanced controls algorithms and approaches. A particular emphasis is placed upon harsh environment sensing for compatibility with high temperature, erosive, corrosive, and highly reducing or oxidizing environments associated with large-scale centralized power generation. An overview of the full sensors and controls portfolio is presented and a selected set of current and recent research successes and on-going projects are highlighted. A more detailed emphasis will be placed on an overview of the current research thrusts and successes of the in-house sensor material and device research efforts that have been established to support the program.

  2. Advances in materials for room temperature hydrogen sensors.

    PubMed

    Arya, Sunil K; Krishnan, Subramanian; Silva, Hayde; Jean, Sheila; Bhansali, Shekhar

    2012-06-21

    Hydrogen (H(2)), as a source of energy, continues to be a compelling choice in applications ranging from fuel cells and propulsion systems to feedstock for chemical, metallurgical and other industrial processes. H(2), being a clean, reliable, and affordable source, is finding ever increasing use in distributed electric power generation and H(2) fuelled cars. Although still under 0.1%, the distributed use of H(2) is the fastest growing area. In distributed H(2) storage, distribution, and consumption, safety continues to be a critical aspect. Affordable safety systems for distributed H(2) applications are critical for the H(2) economy to take hold. Advances in H(2) sensors are driven by specificity, reliability, repeatability, stability, cost, size, response time, recovery time, operating temperature, humidity range, and power consumption. Ambient temperature sensors for H(2) detection are increasingly being explored as they offer specificity, stability and robustness of high temperature sensors with lower operational costs and significantly longer operational lifetimes. This review summarizes and highlights recent developments in room temperature H(2) sensors. PMID:22582176

  3. Improving long-term global precipitation dataset using multi-sensor surface soil moisture retrievals and the soil moisture analysis rainfall tool (SMART)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using multiple historical satellite surface soil moisture products, the Kalman Filtering-based Soil Moisture Analysis Rainfall Tool (SMART) is applied to improve the accuracy of a multi-decadal global daily rainfall product that has been bias-corrected to match the monthly totals of available rain g...

  4. Soil moisture retrieval from WindSat using the single channel algorithm toward a blended global soil moisture product from multiple microwave sensors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil moisture has long been recognized as one of the critical land surface initial conditions for numerical weather, climate hydrological predictions, particularly for transition zones between dry and humid climates. However, none of the currently existing soil moisture products has been used operat...

  5. Recent Advances in Skin-Inspired Sensors Enabled by Nanotechnology

    NASA Astrophysics Data System (ADS)

    Loh, Kenneth J.; Azhari, Faezeh

    2012-07-01

    The highly optimized performance of nature's creations and biological assemblies has inspired the development of their bio-inspired artificial counterparts that can potentially outperform conventional systems. In particular, the skin of humans, animals, and insects exhibits unique functionalities and properties and has subsequently led to active research in developing skin-inspired sensors. This paper presents a summary of selected work related to skin-inspired tactile, distributed strain, and artificial hair cell flow sensors, with a particular focus on technologies enabled by recent advancements in the nanotechnology domain. The purpose is not to present a comprehensive review on this broad subject matter but rather to use selected work to outline the diversity of current research activities.

  6. Advanced processing for high-bandwidth sensor systems

    NASA Astrophysics Data System (ADS)

    Szymanski, John J.; Blain, Phil C.; Bloch, Jeffrey J.; Brislawn, Christopher M.; Brumby, Steven P.; Cafferty, Maureen M.; Dunham, Mark E.; Frigo, Janette R.; Gokhale, Maya; Harvey, Neal R.; Kenyon, Garrett; Kim, Won-Ha; Layne, J.; Lavenier, Dominique D.; McCabe, Kevin P.; Mitchell, Melanie; Moore, Kurt R.; Perkins, Simon J.; Porter, Reid B.; Robinson, S.; Salazar, Alfonso; Theiler, James P.; Young, Aaron C.

    2000-11-01

    Compute performance and algorithm design are key problems of image processing and scientific computing in general. For example, imaging spectrometers are capable of producing data in hundreds of spectral bands with millions of pixels. These data sets show great promise for remote sensing applications, but require new and computationally intensive processing. The goal of the Deployable Adaptive Processing Systems (DAPS) project at Los Alamos National Laboratory is to develop advanced processing hardware and algorithms for high-bandwidth sensor applications. The project has produced electronics for processing multi- and hyper-spectral sensor data, as well as LIDAR data, while employing processing elements using a variety of technologies. The project team is currently working on reconfigurable computing technology and advanced feature extraction techniques, with an emphasis on their application to image and RF signal processing. This paper presents reconfigurable computing technology and advanced feature extraction algorithm work and their application to multi- and hyperspectral image processing. Related projects on genetic algorithms as applied to image processing will be introduced, as will the collaboration between the DAPS project and the DARPA Adaptive Computing Systems program. Further details are presented in other talks during this conference and in other conferences taking place during this symposium.

  7. Highly processable method for the construction of miniature conducting polymer moisture sensors

    NASA Astrophysics Data System (ADS)

    McGovern, Scott T.; Spinks, Geoffrey M.; Wallace, Gordon G.

    2005-02-01

    A polymer blend incorporating polyaniline (PAn) was used as a sensing medium in the construction of a resistance based humidity sensor. Aniline monomer was polymerised to PAn emeraldine salt (ES) in the presence of poly (butyl acrylate-co-vinyl acetate) and the processable blend was developed by redissolving 1-2 w/w% of the resulting sensing polymer residue in dichloromethane (DCM). Some of this residue was washed in ammonia solution to de-dope the PAn to emeraldine base (EB) to act as a protective layer on the surface of the sensing polymer. This residue was then washed with distilled water until a neutral pH was realised with the waste water, dried and redissolved in DCM at 1-2 w/w% to create a processable blend barrier polymer solution. The final sensor design utilised 125μm polyester insulated platinum wire as conducting electrodes that were dip coated in the PAn ES blend solution and dried in a desiccator. A protective coating was then applied by dip coating in the EB blend solution. The sensors had an overall final thickness of less than 200μm and showed high sensitivity to humidity, low resistance, and good reversibility without hysteresis. The EB protective layer was shown to give more stable and predictable responses to the sensors when placed inside curing epoxies. Polymer based thin film humidity sensors have the advantage that the high processability of the material allows for simple fabrication of a range of geometries including smaller sensor designs. Such sensors may find uses in detecting water content in a number of areas including composite materials, electronic textiles, food/electronics packaging and corrosion detection.

  8. Advanced Sensor Fish Device for ImprovedTurbine Design

    SciTech Connect

    Carlson, Thomas J.

    2009-09-14

    Juvenile salmon (smolts) passing through hydroelectric turbines are subjected to environmental conditions that can potentially kill or injure them. Many turbines are reaching the end of their operational life expectancies and will be replaced with new turbines that incorporate advanced “fish friendly” designs devised to prevent injury and death to fish. To design a fish friendly turbine, it is first necessary to define the current conditions fish encounter. One such device used by biologists at Pacific Northwest National Laboratory was the sensor fish device to collect data that measures the forces fish experience during passage through hydroelectric projects.

  9. WET sensor performance in organic and inorganic media with heterogeneous moisture distribution

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Interest in electronic monitoring of soil water has grown as increased demand for water creates a greater need for effective water management. Relatively inexpensive commercial soil water sensors that use measured dielectric properties to calculate water content, have been developed to address this...

  10. Understanding Soil Moisture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding soil moisture is critical for landscape irrigation management. This landscaep irrigation seminar will compare volumetric and matric potential soil-moisture sensors, discuss the relationship between their readings and demonstrate how to use these data. Soil water sensors attempt to sens...

  11. Advanced Sensors and Controls for Building Applications: Market Assessment and Potential R&D Pathways

    SciTech Connect

    Brambley, M. R.; Haves, P.; McDonald, S. C.; Torcellini, P.; Hansen, D.; Holmberg, D. R.; Roth, K. W.

    2005-04-01

    This document provides a market assessment of existing building sensors and controls and presents a range of technology pathways (R&D options) for pursuing advanced sensors and building control strategies.

  12. On the advance of non-invasive techniques implementation for monitoring moisture distribution in cultural heritage: a case study

    NASA Astrophysics Data System (ADS)

    Inmaculada Martínez Garrido, María; Gómez Heras, Miguel; Fort González, Rafael; Valles Iriso, Javier; José Varas Muriel, María

    2015-04-01

    This work presents a case study developed in San Juan Bautista church in Talamanca de Jarama (12th -16th Century), which have been selected as an example of a historical church with a complex construction with subsequent combination of architectural styles and building techniques and materials. These materials have a differential behavior under the influence of external climatic conditions and constructive facts. Many decay processes related to humidity are affecting the building's walls and also have influence in the environmental dynamics inside the building. A methodology for monitoring moisture distribution on stone and masonry walls and floors was performed with different non-invasive techniques as thermal imaging, wireless sensor networks (WSN), portable moisture meter, electrical resistivity tomography (ERT) and ground-penetrating radar (GPR), in order to the evaluate the effectiveness of these techniques for the knowledge of moisture distribution inside the walls and the humidity origin. North and south oriented sections, both on walls and floors, were evaluated and also a general inspection in the church was carried out with different non-invasive techniques. This methodology implies different monitoring stages for a complete knowledge of the implication of outdoors and indoors conditions on the moisture distribution. Each technique is evaluated according to its effectiveness in the detection of decay processes and maintenance costs. Research funded by Geomateriales (S2013/MIT-2914) and Deterioration of stone materials in the interior of historic buildings as a result induced variation of its microclimate (CGL2011-27902) projects. The cooperation received from the Complutense University of Madrid's Research Group Alteración y Conservación de los Materiales Pétreos del Patrimonio (ref. 921349), the Laboratory Network in Science and Technology for Heritage Conservation (RedLabPat, CEI Moncloa) and the Diocese of Alcalá is gratefully acknowledged. MI Mart

  13. Advancing Lidar Sensors Technologies for Next Generation Landing Missions

    NASA Technical Reports Server (NTRS)

    Amzajerdian, Farzin; Hines, Glenn D.; Roback, Vincent E.; Petway, Larry B.; Barnes, Bruce W.; Brewster, Paul F.; Pierrottet, Diego F.; Bulyshev, Alexander

    2015-01-01

    Missions to solar systems bodies must meet increasingly ambitious objectives requiring highly reliable "precision landing", and "hazard avoidance" capabilities. Robotic missions to the Moon and Mars demand landing at pre-designated sites of high scientific value near hazardous terrain features, such as escarpments, craters, slopes, and rocks. Missions aimed at paving the path for colonization of the Moon and human landing on Mars need to execute onboard hazard detection and precision maneuvering to ensure safe landing near previously deployed assets. Asteroid missions require precision rendezvous, identification of the landing or sampling site location, and navigation to the highly dynamic object that may be tumbling at a fast rate. To meet these needs, NASA Langley Research Center (LaRC) has developed a set of advanced lidar sensors under the Autonomous Landing and Hazard Avoidance Technology (ALHAT) project. These lidar sensors can provide precision measurement of vehicle relative proximity, velocity, and orientation, and high resolution elevation maps of the surface during the descent to the targeted body. Recent flights onboard Morpheus free-flyer vehicle have demonstrated the viability of ALHAT lidar sensors for future landing missions to solar system bodies.

  14. 2D and 3D soil moisture imaging using a sensor-based platform moving inside a subsurface network of pipes

    NASA Astrophysics Data System (ADS)

    Gravalos, I.; Moshou, D.; Loutridis, S.; Gialamas, Th.; Kateris, D.; Bompolas, E.; Tsiropoulos, Z.; Xyradakis, P.; Fountas, S.

    2013-08-01

    In this study a prototype sensor-based platform moving inside a subsurface network of pipes with the task of monitoring the soil moisture content is presented. It comprises of a mobile platform, a modified commercial soil moisture sensor (Diviner 2000), a network of subsurface polyvinylchloride (PVC) access pipes, driving hardware and image processing software. The software allows the composition of two-dimensional (2D) or three-dimensional (3D) images with high accuracy and at a large scale. The 3D soil moisture images are created by using 2D slices for better illustration of the soil moisture variability. Three case studies of varying soil moisture content using an experimental soil tank were examined. In the first case study, the irrigation water was applied uniformly on the entire tank surface. In second and third case studies, the irrigation water was applied uniformly only on the surface of the intermediate and last part of the soil tank respectively. The processed images give a detailed description of the soil moisture distribution of a layer at 15 cm depth under the soil surface in the tank. In all case studies that have been investigated, the distribution of soil moisture was characterized by a significant variability (difference between poorly and well-drained regions) of the soil tank. A very poorly-drained region was located in the middle of the soil tank, while well-drained soil areas were located southwest and northeast. The knowledge of the spatial and temporal distribution of soil moisture is a valuable tool for proper management of crop irrigation.

  15. Acoustic wave (AW) based moisture sensor for use with corrosive gases

    DOEpatents

    Pfeifer, Kent B.; Frye, Gregory C.; Schneider, Thomas W.

    1996-01-01

    Moisture corrosive gas stream is measured as a function of the difference in resonant frequencies between two acoustic wave (AW) devices, each with a film which accepts at least one of the components of the gas stream. One AW is located in the gas stream while the other is located outside the gas stream but in the same thermal environment. In one embodiment, the film is a hydrophilic material such as SiO.sub.2. In another embodiment, the SiO.sub.2 is covered with another film which is impermeable to the corrosive gas, such that the AW device in the gas stream measures only the water vapor. In yet another embodiment, the film comprises polyethylene oxide which is hydrophobic and measures only the partial pressure of the corrosive gas. Other embodiments allow for compensation of drift in the system.

  16. Acoustic wave (AW) based moisture sensor for use with corrosive gases

    DOEpatents

    Pfeifer, K.B.; Frye, G.C.; Schneider, T.W.

    1996-11-05

    Moisture corrosive gas stream is measured as a function of the difference in resonant frequencies between two acoustic wave (AW) devices, each with a film which accepts at least one of the components of the gas stream. One AW is located in the gas stream while the other is located outside the gas stream but in the same thermal environment. In one embodiment, the film is a hydrophilic material such as SiO{sub 2}. In another embodiment, the SiO{sub 2} is covered with another film which is impermeable to the corrosive gas, such that the AW device in the gas stream measures only the water vapor. In yet another embodiment, the film comprises polyethylene oxide which is hydrophobic and measures only the partial pressure of the corrosive gas. Other embodiments allow for compensation of drift in the system. 8 figs.

  17. Capturing 3D resistivity of semi-arid karstic subsurface in varying moisture conditions using a wireless sensor network

    NASA Astrophysics Data System (ADS)

    Barnhart, K.; Oden, C. P.

    2012-12-01

    The dissolution of soluble bedrock results in surface and subterranean karst channels, which comprise 7-10% of the dry earth's surface. Karst serves as a preferential conduit to focus surface and subsurface water but it is difficult to exploit as a water resource or protect from pollution because of irregular structure and nonlinear hydrodynamic behavior. Geophysical characterization of karst commonly employs resistivity and seismic methods, but difficulties arise due to low resistivity contrast in arid environments and insufficient resolution of complex heterogeneous structures. To help reduce these difficulties, we employ a state-of-the-art wireless geophysical sensor array, which combines low-power radio telemetry and solar energy harvesting to enable long-term in-situ monitoring. The wireless aspect removes topological constraints common with standard wired resistivity equipment, which facilitates better coverage and/or sensor density to help improve aspect ratio and resolution. Continuous in-situ deployment allows data to be recorded according to nature's time scale; measurements are made during infrequent precipitation events which can increase resistivity contrast. The array is coordinated by a smart wireless bridge that continuously monitors local soil moisture content to detect when precipitation occurs, schedules resistivity surveys, and periodically relays data to the cloud via 3G cellular service. Traditional 2/3D gravity and seismic reflection surveys have also been conducted to clarify and corroborate results.

  18. Continental-Scale Evaluation of Assimilated Soil Moisture Retrievals From the Advanced Microwave Scanning Radiometer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil moisture is a fundamental data source used in crop growth stage and crop stress models developed by the USDA Foreign Agriculture Service for global crop estimation. USDA’s International Production Assessment Division (IPAD) of the Office of Global Analysis (OGA). Currently, the PECAD DSS utiliz...

  19. A 868MHz-based wireless sensor network for ground truthing of soil moisture for a hyperspectral remote sensing campaign - design and preliminary results

    NASA Astrophysics Data System (ADS)

    Näthe, Paul; Becker, Rolf

    2014-05-01

    Soil moisture and plant available water are important environmental parameters that affect plant growth and crop yield. Hence, they are significant parameters for vegetation monitoring and precision agriculture. However, validation through ground-based soil moisture measurements is necessary for accessing soil moisture, plant canopy temperature, soil temperature and soil roughness with airborne hyperspectral imaging systems in a corresponding hyperspectral imaging campaign as a part of the INTERREG IV A-Project SMART INSPECTORS. At this point, commercially available sensors for matric potential, plant available water and volumetric water content are utilized for automated measurements with smart sensor nodes which are developed on the basis of open-source 868MHz radio modules, featuring a full-scale microcontroller unit that allows an autarkic operation of the sensor nodes on batteries in the field. The generated data from each of these sensor nodes is transferred wirelessly with an open-source protocol to a central node, the so-called "gateway". This gateway collects, interprets and buffers the sensor readings and, eventually, pushes the data-time series onto a server-based database. The entire data processing chain from the sensor reading to the final storage of data-time series on a server is realized with open-source hardware and software in such a way that the recorded data can be accessed from anywhere through the internet. It will be presented how this open-source based wireless sensor network is developed and specified for the application of ground truthing. In addition, the system's perspectives and potentials with respect to usability and applicability for vegetation monitoring and precision agriculture shall be pointed out. Regarding the corresponding hyperspectral imaging campaign, results from ground measurements will be discussed in terms of their contributing aspects to the remote sensing system. Finally, the significance of the wireless sensor

  20. USSP-IAEA WORKSHOP ON ADVANCED SENSORS FOR SAFEGUARDS.

    SciTech Connect

    PEPPER,S.; QUEIROLO, A.; ZENDEL, M.; WHICHELLO, J.; ANNESE, C.; GRIEBE, J.; GRIEBE, R.

    2007-11-13

    The IAEA Medium Term Strategy (2006-2011) defines a number of specific goals in respect to the IAEA's ability to provide assurances to the international community regarding the peaceful use of nuclear energy through States adherences to their respective non-proliferation treaty commitments. The IAEA has long used and still needs the best possible sensors to detect and measure nuclear material. The Department of Safeguards, recognizing the importance of safeguards-oriented R&D, especially targeting improved detection capabilities for undeclared facilities, materials and activities, initiated a number of activities in early 2005. The initiatives included letters to Member State Support Programs (MSSPs), personal contacts with known technology holders, topical meetings, consultant reviews of safeguards technology, and special workshops to identify new and novel technologies and methodologies. In support of this objective, the United States Support Program to IAEA Safeguards hosted a workshop on ''Advanced Sensors for Safeguards'' in Santa Fe, New Mexico, from April 23-27, 2007. The Organizational Analysis Corporation, a U.S.-based management consulting firm, organized and facilitated the workshop. The workshop's goal was to help the IAEA identify and plan for new sensors for safeguards implementation. The workshop, which was attended by representatives of seven member states and international organizations, included presentations by technology holders and developers on new technologies thought to have relevance to international safeguards, but not yet in use by the IAEA. The presentations were followed by facilitated breakout sessions where the participants considered two scenarios typical of what IAEA inspectors might face in the field. One scenario focused on an enrichment plant; the other scenario focused on a research reactor. The participants brainstormed using the technologies presented by the participants and other technologies known to them to propose

  1. SoilSCAPE in-Situ Observations of Soil Moisture for SMAP Validation: Pushing the Envelopes of Spatial Coverage and Energy Efficiency in Sparse Wireless Sensor Networks (Invited)

    NASA Astrophysics Data System (ADS)

    Moghaddam, M.; Silva, A.; Clewley, D.; Akbar, R.; Entekhabi, D.

    2013-12-01

    Soil Moisture Sensing Controller and oPtimal Estimator (SoilSCAPE) is a wireless in-situ sensor network technology, developed under the support of NASA ESTO/AIST program, for multi-scale validation of soil moisture retrievals from the Soil Moisture Active and Passive (SMAP) mission. The SMAP sensor suite is expected to produce soil moisture retrievals at 3 km scale from the radar instrument, at 36 km from the radiometer, and at 10 km from the combination of the two sensors. To validate the retrieved soil moisture maps at any of these scales, it is necessary to perform in-situ observations at multiple scales (ten, hundreds, and thousands of meters), representative of the true spatial variability of soil moisture fields. The most recent SoilSCAPE network, deployed in the California central valley, has been designed, built, and deployed to accomplish this goal, and is expected to become a core validation site for SMAP. The network consists of up to 150 sensor nodes, each comprised of 3-4 soil moisture sensors at various depths, deployed over a spatial extent of 36 km by 36 km. The network contains multiple sub-networks, each having up to 30 nodes, whose location is selected in part based on maximizing the land cover diversity within the 36 km cell. The network has achieved unprecedented energy efficiency, longevity, and spatial coverage using custom-designed hardware and software protocols. The network architecture utilizes a nested strategy, where a number of end devices (EDs) communicate to a local coordinator (LC) using our recently developed hardware with ultra-efficient circuitry and best-effort-timeslot allocation communication protocol. The LCs in turn communicates with the base station (BS) via text messages and a new compression scheme. The hardware and software technologies required to implement this latest deployment of the SoilSCAPE network will be presented in this paper, and several data sets resulting from the measurements will be shown. The data are

  2. Solar extreme ultraviolet sensor and advanced langmuir probe

    NASA Technical Reports Server (NTRS)

    Voronka, N. R.; Block, B. P.; Carignan, G. R.

    1992-01-01

    For more than two decades, the staff of the Space Physics Research Laboratory (SPRL) has collaborated with the Goddard Space Flight Center (GSFC) in the design and implementation of Langmuir probes (LP). This program of probe development under the direction of Larry Brace of GSFC has evolved methodically with innovations to: improve measurement precision, increase the speed of measurement, and reduce the weight, size, power consumption and data rate of the instrument. Under contract NAG5-419 these improvements were implemented and are what characterize the Advanced Langmuir Probe (ALP). Using data from the Langmuir Probe on the Pioneer Venus Orbiter, Brace and Walter Hoegy of GSFC demonstrated a novel method of monitoring the solar extreme ultraviolet (EUV) flux. This led to the idea of developing a sensor similar to a Langmuir probe specifically designed to measure solar EUV (SEUV) that uses a similar electronics package. Under this contract, a combined instrument package of the ALP and SEUV sensor was to be designed, constructed, and laboratory tested. Finally the instrument was to be flight tested as part of sounding rocket experiment to acquire the necessary data to validate this method for possible use in future earth and planetary aeronomy missions. The primary purpose of this contract was to develop the electronics hardware and software for this instrument, since the actual sensors were suppied by GSFC. Due to budget constraints, only a flight model was constructed. These electronics were tested and calibrated in the laboratory, and then the instrument was integrated into the rocket payload at Wallops Flight Facility where it underwent environmental testing. After instrument recalibration at SPRL, the payload was reintegrated and launched from the Poker Flat Research Range near Fairbanks Alaska. The payload was successfully recovered and after refurbishment underwent further testing and developing to improve its performance for future use.

  3. Recent advances toward a fiber optic sensor for nerve agent

    NASA Astrophysics Data System (ADS)

    Beshay, Manal; Cordero, Steven R.; Mukamal, Harold; Ruiz, David; Lieberman, Robert A.

    2008-04-01

    We report advances made on the development of a fiber optic nerve agent sensor having its entire length as the sensing element. Upon exposure to sarin gas or its simulant, diisopropyl fluorophosphate, the cladding changes color resulting in an alteration of the light intensity throughput. The optical fiber is multimode and consists of a fused-silica core and a nerve agent sensitive cladding. The absorption characteristics of the cladding affect the fiber's spectral attenuation and limit the length of light guiding fiber that can be deployed continuously. The absorption of the cladding is also dependent on the sensor formulation, which in turn influences the sensitivity of the fiber. In this paper, data related to the trade-off of sensitivity, spectral attenuation, and length of fiber challenged will be reported. The fiber is mass produced using a conventional fiber optic draw tower. This technology could be used to protect human resources and buildings from dangerous chemical attacks, particularly when large areas or perimeters must be covered. It may also be used passively to determine how well such areas have been decontaminated.

  4. Monitoring Soil Moisture in Saline Soils using Neutron Probe, Time Domain Reflectometry, and Heat Dissipation Sensor Measurements

    NASA Astrophysics Data System (ADS)

    Reedy, R. C.

    2004-12-01

    Knowledge of spatial and temporal variability of soil moisture content (SMC) is important for understanding of land-atmosphere interactions, groundwater recharge, and water balance. Different measurement methods have contrasting strengths and weaknesses. Traditional neutron probe measurements cannot be automated and are time-intensive. However, there are widespread problems with using automated time domain reflectometry (TDR) for monitoring SMC due to high soil salinity/electrical conductivity. The objective of this study was to show how these limitations can be overcome by using multiple methods. Neutron probe access tubes, TDR probes (coated and uncoated), and heat dissipation sensors (HDS) were installed at an engineered field laboratory in a semiarid setting. The texture of the soils was sandy clay loam, including 0.3 m of uncompacted topsoil with low salinity and non-swelling clays underlain by 1.0 to 1.7 m of compacted subsoil with high salinity and swelling clays. A neutron probe was used to manually measure SMC profiles at 20 locations at approximately monthly intervals over a 3.5 yr period. During a 4 to 5 yr overlapping period, daily automated measurements were made at 8 locations of apparent dielectric constant (Ka) and bulk electrical conductivity (EC) profiles using TDR (128 probes) and matric potential profiles using HDS (54 sensors). TDR measurements in the high salinity soils were effectively calibrated in situ using neutron probe measurements. Modeled estimates of spatial average water content were generally within 0.01 m3/m3. A similar approach was used to combine neutron probe, TDR, and HDS measurements to generate in situ soil water retention functions. These functions were then used to estimate SMC from matric potential measurements. These approaches allowed SMC to be monitored in high salinity swelling soils and provided much higher resolution time series than were obtained from the limited neutron probe measurements.

  5. Battery-free Wireless Sensor Network For Advanced Fossil-Fuel Based Power Generation

    SciTech Connect

    Yi Jia

    2011-02-28

    This report summarizes technical progress achieved during the project supported by the Department of Energy under Award Number DE-FG26-07NT4306. The aim of the project was to conduct basic research into battery-free wireless sensing mechanism in order to develop novel wireless sensors and sensor network for physical and chemical parameter monitoring in a harsh environment. Passive wireless sensing platform and five wireless sensors including temperature sensor, pressure sensor, humidity sensor, crack sensor and networked sensors developed and demonstrated in our laboratory setup have achieved the objective for the monitoring of various physical and chemical parameters in a harsh environment through remote power and wireless sensor communication, which is critical to intelligent control of advanced power generation system. This report is organized by the sensors developed as detailed in each progress report.

  6. An Evaluation of Soil Moisture Retrievals Using Aircraft and Satellite Passive Microwave Observations during SMEX02

    NASA Technical Reports Server (NTRS)

    Bolten, John D.; Lakshmi, Venkat

    2009-01-01

    The Soil Moisture Experiments conducted in Iowa in the summer of 2002 (SMEX02) had many remote sensing instruments that were used to study the spatial and temporal variability of soil moisture. The sensors used in this paper (a subset of the suite of sensors) are the AQUA satellite-based AMSR-E (Advanced Microwave Scanning Radiometer- Earth Observing System) and the aircraft-based PSR (Polarimetric Scanning Radiometer). The SMEX02 design focused on the collection of near simultaneous brightness temperature observations from each of these instruments and in situ soil moisture measurements at field- and domain- scale. This methodology provided a basis for a quantitative analysis of the soil moisture remote sensing potential of each instrument using in situ comparisons and retrieved soil moisture estimates through the application of a radiative transfer model. To this end, the two sensors are compared with respect to their estimation of soil moisture.

  7. X-Ray Calibration Facility/Advanced Video Guidance Sensor Test

    NASA Technical Reports Server (NTRS)

    Johnston, N. A. S.; Howard, R. T.; Watson, D. W.

    2004-01-01

    The advanced video guidance sensor was tested in the X-Ray Calibration facility at Marshall Space Flight Center to establish performance during vacuum. Two sensors were tested and a timeline for each are presented. The sensor and test facility are discussed briefly. A new test stand was also developed. A table establishing sensor bias and spot size growth for several ranges is detailed along with testing anomalies.

  8. AlMn Transition Edge Sensors for Advanced ACTPol

    NASA Technical Reports Server (NTRS)

    Li, Dale; Austermann, Jason E.; Beall, James A.; Tucker, Daniel T.; Duff, Shannon M.; Gallardo, Patricio A.; Henderson, Shawn W.; Hilton, Gene C.; Ho, Shuay-Pwu; Hubmayr, Johannes; Koopman, Brian J.; McMahon, Jeffrey J.; Nati, Federico; Niemack, Michael D.; Pappas, Christine G.; Salatino, Maria; Schmitt, Benjamin L.; Simon, Sara M.; Staggs, Suzanne T.; Van Lanen, Jeff; Ward, Jonathan T.; Wollack, Edward J.

    2016-01-01

    Advanced ACTPol (Adv ACT) will use an array of multichroic polarization sensitive AIMn transition edge sensor (TES) bolometers read out through time-division multiplexing. Aluminum doped with a low concentration of manganese can be deposited to a bulk film thickness for a more reliable superconducting critical temperature uniformity compared to thin bilayers. To build the TES, the AlMn alloy is deposited, over Nb wiring, to a specific thickness to set the TES normal resistance. The doping concentration of manganese coarsely defines the TES critical temperature, while a fine tuning is achieved by heating the deposited film to a specific temperature. The TES island is connected to the thermal bath via four silicon-nitride membranes, where their geometry defines the thermal conductance to the temperature of the bath. Lastly, the TES heat capacity is increased by addition of PdAu electrically connected to the AlMn film. Designs and performance characteristics of these AlMn TESs are presented for use in AdvACT.

  9. AlMn Transition Edge Sensors for Advanced ACTPol

    NASA Astrophysics Data System (ADS)

    Li, Dale; Austermann, Jason E.; Beall, James A.; Becker, Daniel T.; Duff, Shannon M.; Gallardo, Patricio A.; Henderson, Shawn W.; Hilton, Gene C.; Ho, Shuay-Pwu; Hubmayr, Johannes; Koopman, Brian J.; McMahon, Jeffrey J.; Nati, Federico; Niemack, Michael D.; Pappas, Christine G.; Salatino, Maria; Schmitt, Benjamin L.; Simon, Sara M.; Staggs, Suzanne T.; Van Lanen, Jeff; Ward, Jonathan T.; Wollack, Edward J.

    2016-07-01

    Advanced ACTPol (AdvACT) will use an array of multichroic polarization-sensitive AlMn transition edge sensor (TES) bolometers read out through time-division multiplexing. Aluminum doped with a low concentration of manganese can be deposited to a bulk film thickness for a more reliable superconducting critical temperature uniformity compared to thin bilayers. To build the TES, the AlMn alloy is deposited, over Nb wiring, to a specific thickness to set the TES normal resistance. The doping concentration of manganese coarsely defines the TES critical temperature, while a fine tuning is achieved by heating the deposited film to a specific temperature. The TES island is connected to the thermal bath via four silicon-nitride membranes, where their geometry defines the thermal conductance to the temperature of the bath. Lastly, the TES heat capacity is increased by addition of PdAu electrically connected to the AlMn film. Designs and performance characteristics of these AlMn TESs are presented for use in AdvACT.

  10. Sharpening advanced land imager multispectral data using a sensor model

    USGS Publications Warehouse

    Lemeshewsky, G.P.

    2005-01-01

    The Advanced Land Imager (ALI) instrument on NASA's Earth Observing One (EO-1) satellite provides for nine spectral bands at 30m ground sample distance (GSD) and a 10m GSD panchromatic band. This report describes an image sharpening technique where the higher spatial resolution information of the panchromatic band is used to increase the spatial resolution of ALI multispectral (MS) data. To preserve the spectral characteristics, this technique combines reported deconvolution deblurring methods for the MS data with highpass filter-based fusion methods for the Pan data. The deblurring process uses the point spread function (PSF) model of the ALI sensor. Information includes calculation of the PSF from pre-launch calibration data. Performance was evaluated using simulated ALI MS data generated by degrading the spatial resolution of high resolution IKONOS satellite MS data. A quantitative measure of performance was the error between sharpened MS data and high resolution reference. This report also compares performance with that of a reported method that includes PSF information. Preliminary results indicate improved sharpening with the method reported here.

  11. Fiber optic (flight quality) sensors for advanced aircraft propulsion

    NASA Technical Reports Server (NTRS)

    Poppel, Gary L.

    1994-01-01

    Development of flight prototype, fiber-optic sensing system components for measuring nine sensed parameters (three temperatures, two speeds, three positions, and one flame) on an F404-400 aircraft engine is described. Details of each sensor's design, functionality, and environmental testing, and the electro-optics architecture for sensor signal conditioning are presented. Eight different optical sensing techniques were utilized. Design, assembly, and environmental testing of an engine-mounted, electro-optics chassis unit (EOU), providing MIL-C-1553 data output, are related. Interconnection cables and connectors between the EOU and the sensors are identified. Results of sensor/cable/circuitry integrated testing, and installation and ground testing of the sensor system on an engine in October 1993 and April 1994 are given, including comparisons with the engine control system's electrical sensors. Lessons learned about the design, fabrication, testing, and integration of the sensor system components are included.

  12. Estimating root-zone moisture and evapotranspiration with AVHRR data[Advanced Very High Resolution Radiometer

    SciTech Connect

    Song, J.; Wesely, M. L.

    1999-10-08

    The parameterized subgrid-scale surface fluxes (PASS) model uses satellite data and limited surface observations to infer root-zone available moisture content and evapotranspiration rate with moderate spatial resolution over extended terrestrial areas. The ultimate goal of this work is to produce estimates of water loss by evapotranspiration, for application in hydrological models. The major advantage to the method is that it can be applied to areas having diverse surface characteristics where direct surface flux measurements either do not exist or are not feasible and where meteorological data are available from only a limited number of ground stations. The emphasis of this work with the PASS model is on improving (1) methods of using satellite remote sensing data to derive the essential parameters for individual types of surfaces over large areas, (2) algorithms for describing the interactions of near-surface atmospheric conditions with surface processes, and (3) algorithms for computing surface energy and water vapor flux at a scale close to the size of a satellite-derived image pixel. The PASS approach is being developed and tested further with observations from the 1997 Cooperative Atmosphere-Surface Exchange Study (CASES-97) at the Atmospheric Boundary Layer Experiments (ABLE) site in the Walnut River Watershed (WRW), an area of about 5,000 km{sup 2} in southern Kansas. Here the authors describe some of the progress made since the previous report.

  13. Wireless Sensor Network for Advanced Energy Management Solutions

    SciTech Connect

    Peter J. Theisen; Bin Lu, Charles J. Luebke

    2009-09-23

    Eaton has developed an advanced energy management solution that has been deployed to several Industries of the Future (IoF) sites. This demonstrated energy savings and reduced unscheduled downtime through an improved means for performing predictive diagnostics and energy efficiency estimation. Eaton has developed a suite of online, continuous, and inferential algorithms that utilize motor current signature analysis (MCSA) and motor power signature analysis (MPSA) techniques to detect and predict the health condition and energy usage condition of motors and their connect loads. Eaton has also developed a hardware and software platform that provided a means to develop and test these advanced algorithms in the field. Results from lab validation and field trials have demonstrated that the developed advanced algorithms are able to detect motor and load inefficiency and performance degradation. Eaton investigated the performance of Wireless Sensor Networks (WSN) within various industrial facilities to understand concerns about topology and environmental conditions that have precluded broad adoption by the industry to date. A Wireless Link Assessment System (WLAS), was used to validate wireless performance under a variety of conditions. Results demonstrated that wireless networks can provide adequate performance in most facilities when properly specified and deployed. Customers from various IoF expressed interest in applying wireless more broadly for selected applications, but continue to prefer utilizing existing, wired field bus networks for most sensor based applications that will tie into their existing Computerized Motor Maintenance Systems (CMMS). As a result, wireless technology was de-emphasized within the project, and a greater focus placed on energy efficiency/predictive diagnostics. Commercially available wireless networks were only utilized in field test sites to facilitate collection of motor wellness information, and no wireless sensor network products were

  14. Early conclusions of the soil moisture active passive Marena Oklahoma in situ sensor testbed (SMAP-Moisst)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Monitoring soil moisture state has been increasing in importance as climate patterns become more unpredictable. Remote sensing technologies have been developed and are approaching operational use, however, there is still a need to monitor soil moisture via in situ networks to maintain satellite vali...

  15. Field-scale moisture estimates using COSMOS sensors: a validation study with temporary networks and leaf-area-indices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Cosmic-ray Soil Moisture Observing System (COSMOS) is a new and innovative method for estimating surface and near surface soil moisture at large (~700 m) scales. This system accounts for liquid water within its measurement volume. Many of the sites used in the early validation of the system had...

  16. Electro-optic architecture for servicing sensors and actuators in advanced aircraft propulsion systems

    NASA Technical Reports Server (NTRS)

    Poppel, G. L.; Glasheen, W. M.

    1989-01-01

    A detailed design of a fiber optic propulsion control system, integrating favored sensors and electro-optics architecture is presented. Layouts, schematics, and sensor lists describe an advanced fighter engine system model. Components and attributes of candidate fiber optic sensors are identified, and evaluation criteria are used in a trade study resulting in favored sensors for each measurand. System architectural ground rules were applied to accomplish an electro-optics architecture for the favored sensors. A key result was a considerable reduction in signal conductors. Drawings, schematics, specifications, and printed circuit board layouts describe the detailed system design, including application of a planar optical waveguide interface.

  17. Advances in fiber optic sensors for in-vivo monitoring

    NASA Astrophysics Data System (ADS)

    Baldini, Francesco; Mignani, Anna G.

    1995-09-01

    Biomedical fiber-optic sensors are attractive for the measurement of both physical and chemical parameters as well as for spectral measurements directly performed on the patient. An overview of fiber-optic sensors for in vivo monitoring is given, with particular attention to the advantages that these sensors are able to offer in different fields of application such as cardiovascular and intensive care, angiology, gastroenterology, ophthalmology, oncology, neurology, dermatology, and dentistry.

  18. Satellite Advanced Attitude Sensors at UNINA Lab GNC

    NASA Astrophysics Data System (ADS)

    Accardo, D.

    This paper presents the most recent activities at the Laboratory of Guidance, Navigation, and Control of the Department of Industrial Engineering dealing with design, development, and test of attitude sensors for space applications, in particular a micro sun sensor and a star tracker, along with laboratory facilities to test them indoors. The paper presents a detailed description of sensors as well as test facilities, and the results of two test campaigns that assessed the performance of the two devices.

  19. Why different passive microwave algorithms give different soil moisture retrievals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several algorithms have been used to retrieve surface soil moisture from brightness temperature observations provided by low frequency microwave satellite sensors such as the Advanced Microwave Scanning Radiometer on NASA EOS satellite Aqua (AMSR-E). Most of these algorithms have originated from the...

  20. Condition monitoring through advanced sensor and computational technology : final report (January 2002 to May 2005).

    SciTech Connect

    Kim, Jung-Taek; Luk, Vincent K.

    2005-05-01

    The overall goal of this joint research project was to develop and demonstrate advanced sensors and computational technology for continuous monitoring of the condition of components, structures, and systems in advanced and next-generation nuclear power plants (NPPs). This project included investigating and adapting several advanced sensor technologies from Korean and US national laboratory research communities, some of which were developed and applied in non-nuclear industries. The project team investigated and developed sophisticated signal processing, noise reduction, and pattern recognition techniques and algorithms. The researchers installed sensors and conducted condition monitoring tests on two test loops, a check valve (an active component) and a piping elbow (a passive component), to demonstrate the feasibility of using advanced sensors and computational technology to achieve the project goal. Acoustic emission (AE) devices, optical fiber sensors, accelerometers, and ultrasonic transducers (UTs) were used to detect mechanical vibratory response of check valve and piping elbow in normal and degraded configurations. Chemical sensors were also installed to monitor the water chemistry in the piping elbow test loop. Analysis results of processed sensor data indicate that it is feasible to differentiate between the normal and degraded (with selected degradation mechanisms) configurations of these two components from the acquired sensor signals, but it is questionable that these methods can reliably identify the level and type of degradation. Additional research and development efforts are needed to refine the differentiation techniques and to reduce the level of uncertainties.

  1. Sensor Web Technology Challenges and Advancements for the Earth Science Decadal Survey Era

    NASA Technical Reports Server (NTRS)

    Norton, Charles D.; Moe, Karen

    2011-01-01

    This paper examines the Earth science decadal survey era and the role ESTO developed sensor web technologies can contribute to the scientific observations. This includes hardware and software technology advances for in-situ and in-space measurements. Also discussed are emerging areas of importance such as the potential of small satellites for sensor web based observations as well as advances in data fusion critical to the science and societal benefits of future missions, and the challenges ahead.

  2. System performance advances of 18-mm and 16-mm subminiature image intensifier sensors

    NASA Astrophysics Data System (ADS)

    Thomas, Nils I.

    2000-11-01

    Night vision system design has been centered aroudn the An/AVS-6 and AN/PVS-7 night vision goggle systems for the past 20 years. Goggle performance has improved during this time through increased performance of the image intensifier sensor, primarily the Omni IV sensor from ITT Industries Night Vision. Most of this improvement has been at the optimal light level (1E-3 fc scene illumination). Recent advances in image sensor performance from the filmless Generation (Gen) IV sensors has increased the low light level performance of night vision devices from 0.3 cy/mr to 0.7 cy/mr. In addition, sensor packaging design requirements have forced night vision sensor manufactures to design light weight, small volume sensors. ITT recently has designed such a sensor in a 16-mm format. This sensor if 50% lighter, up to 50% shorter, and has design features that simplify the objective lens design. New night vision goggles have been, and are being, designed which reduce the perceived head-supported weight. This paper presents signal-to-noise ratio, halo, and other film-less sensor data and similar 16-mm subminiature sensor data. The resulting system performance data will be described. Finally, the system design improvements and relationships with the subminiature 16-mm subminiature sensor will be given.

  3. Advances on Sensor Web for Internet of Things

    NASA Astrophysics Data System (ADS)

    Liang, S.; Bermudez, L. E.; Huang, C.; Jazayeri, M.; Khalafbeigi, T.

    2013-12-01

    'In much the same way that HTML and HTTP enabled WWW, the Open Geospatial Consortium (OGC) Sensor Web Enablement (SWE), envisioned in 2001 [1] will allow sensor webs to become a reality.'. Due to the large number of sensor manufacturers and differing accompanying protocols, integrating diverse sensors into observation systems is not a simple task. A coherent infrastructure is needed to treat sensors in an interoperable, platform-independent and uniform way. SWE standardizes web service interfaces, sensor descriptions and data encodings as building blocks for a Sensor Web. SWE standards are now mature specifications (version 2.0) with approved OGC compliance test suites and tens of independent implementations. Many earth and space science organizations and government agencies are using the SWE standards to publish and share their sensors and observations. While SWE has been demonstrated very effective for scientific sensors, its complexity and the computational overhead may not be suitable for resource-constrained tiny sensors. In June 2012, a new OGC Standards Working Group (SWG) was formed called the Sensor Web Interface for Internet of Things (SWE-IoT) SWG. This SWG focuses on developing one or more OGC standards for resource-constrained sensors and actuators (e.g., Internet of Things devices) while leveraging the existing OGC SWE standards. In the near future, billions to trillions of small sensors and actuators will be embedded in real- world objects and connected to the Internet facilitating a concept called the Internet of Things (IoT). By populating our environment with real-world sensor-based devices, the IoT is opening the door to exciting possibilities for a variety of application domains, such as environmental monitoring, transportation and logistics, urban informatics, smart cities, as well as personal and social applications. The current SWE-IoT development aims on modeling the IoT components and defining a standard web service that makes the

  4. Recent advances in TEC-less uncooled FPA sensor operation

    NASA Astrophysics Data System (ADS)

    Howard, Philip E.; Clarke, John E.; Li, Chuan C.; Yang, John W.; Wong, W. Y.; Bogosyan, Arsen

    2003-09-01

    DRS has previously demonstrated and reported a concept for operating uncooled infrared focal plane arrays (UIRFPA) without the need for UIRFPA temperature regulation. DRS has patented this proprietary technology, which DRS calls TCOMP. TCOMP is a concept that combines an operating algorithm, a sensor architecture and a sensor calibration method, which allow pixel response and offset correction to be performed as a function of the UFPA sensor's operating temperature, thereby eliminating the need for the UIRFPA temperature regulation that would be required otherwise. As a result of the elimination of the temperature regulation requirement, the sensor turn-on time for high performance imaging can be significantly reduced, sensor power is significantly reduced, and the need for stray thermal radiation shields is effectively eliminated. The original TCOMP technique was demonstrated in 1998. Since then DRS has made significant improvements in both the TCOMP algorithm and the calibration process. This paper describes the patented TCOMP concept, presents the results of analysis of the improved TCOMP concept, and provides sensor level data of UIRFPA/sensor performance with the improved TCOMP algorithm.

  5. The diurnal course of soil moisture as measured by various dielectric sensors: Effects of soil temperature and the implications for evaporation estimates

    NASA Astrophysics Data System (ADS)

    Verhoef, A.; Fernández-Gálvez, J.; Diaz-Espejo, A.; Main, B. E.; El-Bishti, M.

    2006-04-01

    Soil moisture content, θ, of a bare and vegetated UK gravelly sandy loam soil (in situ and repacked in small lysimeters) was measured using various dielectric instruments (single-sensor ThetaProbes, multi-sensor Profile Probes, and Aquaflex Sensors), at depths ranging between 0.03 and 1 m, during the summers of 2001 (in situ soil) and 2002 (mini-lysimeters). Half-hourly values of evaporation, E, were calculated from diurnal changes in total soil profile water content, using the soil water balance equation. For the bare soil field, Profile Probes and ML2x ThetaProbes indicated a diurnal course of θ that did not concur with typical soil physical observations: surface layer soil moisture content increased from early morning until about midday, after which θ declined, generally until the early evening. The unexpected course of θ was positively correlated to soil temperature, Ts, also at deeper depths. Aquaflex and ML1 ThetaProbe (older models) outputs, however, reflected common observations: θ increased slightly during the night (capillary rise) and decreased from the morning until late afternoon (as a result of evaporation). For the vegetated plot, the spurious diurnal θ fluctuations were less obvious, because canopy shading resulted in lower amplitudes of Ts. The unrealistic θ profiles measured for the bare and vegetated field sites caused diurnal estimates of E to attain downward daytime and upward night-time values. In the mini-lysimeters, at medium to high moisture contents, θ values measured by (ML2x) ThetaProbes followed a relatively realistic course, and predictions of E from diurnal changes in vertically integrated θ generally compared well with lysimeter estimates of E. However, time courses of θ and E became comparable to those observed for the field plots when the soil in the lysimeters reached relatively low values of θ. Attempts to correct measured θ for fluctuations in Ts revealed that no generally applicable formula could be derived.

  6. Contributions of Precipitation and Soil Moisture Observations to the Skill of Soil Moisture Estimates in a Land Data Assimilation System

    NASA Technical Reports Server (NTRS)

    Reichle, Rolf H.; Liu, Qing; Bindlish, Rajat; Cosh, Michael H.; Crow, Wade T.; deJeu, Richard; DeLannoy, Gabrielle J. M.; Huffman, George J.; Jackson, Thomas J.

    2011-01-01

    The contributions of precipitation and soil moisture observations to the skill of soil moisture estimates from a land data assimilation system are assessed. Relative to baseline estimates from the Modern Era Retrospective-analysis for Research and Applications (MERRA), the study investigates soil moisture skill derived from (i) model forcing corrections based on large-scale, gauge- and satellite-based precipitation observations and (ii) assimilation of surface soil moisture retrievals from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E). Soil moisture skill is measured against in situ observations in the continental United States at 44 single-profile sites within the Soil Climate Analysis Network (SCAN) for which skillful AMSR-E retrievals are available and at four CalVal watersheds with high-quality distributed sensor networks that measure soil moisture at the scale of land model and satellite estimates. The average skill (in terms of the anomaly time series correlation coefficient R) of AMSR-E retrievals is R=0.39 versus SCAN and R=0.53 versus CalVal measurements. The skill of MERRA surface and root-zone soil moisture is R=0.42 and R=0.46, respectively, versus SCAN measurements, and MERRA surface moisture skill is R=0.56 versus CalVal measurements. Adding information from either precipitation observations or soil moisture retrievals increases surface soil moisture skill levels by IDDeltaR=0.06-0.08, and root zone soil moisture skill levels by DeltaR=0.05-0.07. Adding information from both sources increases surface soil moisture skill levels by DeltaR=0.13, and root zone soil moisture skill by DeltaR=0.11, demonstrating that precipitation corrections and assimilation of satellite soil moisture retrievals contribute similar and largely independent amounts of information.

  7. Downscaling Satellite Data for Predicting Catchment-scale Root Zone Soil Moisture with Ground-based Sensors and an Ensemble Kalman Filter

    NASA Astrophysics Data System (ADS)

    Lin, H.; Baldwin, D. C.; Smithwick, E. A. H.

    2015-12-01

    Predicting root zone (0-100 cm) soil moisture (RZSM) content at a catchment-scale is essential for drought and flood predictions, irrigation planning, weather forecasting, and many other applications. Satellites, such as the NASA Soil Moisture Active Passive (SMAP), can estimate near-surface (0-5 cm) soil moisture content globally at coarse spatial resolutions. We develop a hierarchical Ensemble Kalman Filter (EnKF) data assimilation modeling system to downscale satellite-based near-surface soil moisture and to estimate RZSM content across the Shale Hills Critical Zone Observatory at a 1-m resolution in combination with ground-based soil moisture sensor data. In this example, a simple infiltration model within the EnKF-model has been parameterized for 6 soil-terrain units to forecast daily RZSM content in the catchment from 2009 - 2012 based on AMSRE. LiDAR-derived terrain variables define intra-unit RZSM variability using a novel covariance localization technique. This method also allows the mapping of uncertainty with our RZSM estimates for each time-step. A catchment-wide satellite-to-surface downscaling parameter, which nudges the satellite measurement closer to in situ near-surface data, is also calculated for each time-step. We find significant differences in predicted root zone moisture storage for different terrain units across the experimental time-period. Root mean square error from a cross-validation analysis of RZSM predictions using an independent dataset of catchment-wide in situ Time-Domain Reflectometry (TDR) measurements ranges from 0.060-0.096 cm3 cm-3, and the RZSM predictions are significantly (p < 0.05) correlated with TDR measurements [r = 0.47-0.68]. The predictive skill of this data assimilation system is similar to the Penn State Integrated Hydrologic Modeling (PIHM) system. Uncertainty estimates are significantly (p < 0.05) correlated to cross validation error during wet and dry conditions, but more so in dry summer seasons. Developing an

  8. Wireless Sensors and Networks for Advanced Energy Management

    SciTech Connect

    Hardy, J.E.

    2005-05-06

    Numerous national studies and working groups have identified low-cost, very low-power wireless sensors and networks as a critical enabling technology for increasing energy efficiency, reducing waste, and optimizing processes. Research areas for developing such sensor and network platforms include microsensor arrays, ultra-low power electronics and signal conditioning, data/control transceivers, and robust wireless networks. A review of some of the research in the following areas will be discussed: (1) Low-cost, flexible multi-sensor array platforms (CO{sub 2}, NO{sub x}, CO, humidity, NH{sub 3}, O{sub 2}, occupancy, etc.) that enable energy and emission reductions in applications such as buildings and manufacturing; (2) Modeling investments (energy usage and savings to drive capital investment decisions) and estimated uptime improvements through pervasive gathering of equipment and process health data and its effects on energy; (3) Robust, self-configuring wireless sensor networks for energy management; and (4) Quality-of-service for secure and reliable data transmission from widely distributed sensors. Wireless communications is poised to support technical innovations in the industrial community, with widespread use of wireless sensors forecasted to improve manufacturing production and energy efficiency and reduce emissions. Progress being made in wireless system components, as described in this paper, is helping bring these projected improvements to reality.

  9. Effects of Moisture Profiles and Laminate Configuration on the Hygro Stresses in Advanced Composites. [graphite-epoxy composites

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Sinclair, J. H.; Lark, R. F.

    1978-01-01

    An integrated hygrothermo-mechanical theory was used to predict the effects of three moisture profiles on the ply hygro stresses in angleplied laminates. The moisture profiles were linear, parabolic and hyperbolic. Moisture content varied from 1 percent in the exposed ply to zero in the protected ply. The angleplied laminates were of two generic configurations. The results obtained are summarized graphically to illustrate the effects of both moisture profile and laminate configuration. The results indicate that ply transverse tensile hygro stresses may reach sufficiently high magnitudes to cause transply cracking.

  10. The Next Generation Advanced Video Guidance Sensor: Flight Heritage and Current Development

    NASA Technical Reports Server (NTRS)

    Howard, Richard T.; Bryan, Thomas C.

    2009-01-01

    The Next Generation Advanced Video Guidance Sensor (NGAVGS) is the latest in a line of sensors that have flown four times in the last 10 years. The NGAVGS has been under development for the last two years as a long-range proximity operations and docking sensor for use in an Automated Rendezvous and Docking (AR&D) system. The first autonomous rendezvous and docking in the history of the U.S. Space Program was successfully accomplished by Orbital Express, using the Advanced Video Guidance Sensor (AVGS) as the primary docking sensor. That flight proved that the United States now has a mature and flight proven sensor technology for supporting Crew Exploration Vehicles (CEV) and Commercial Orbital Transport Systems (COTS) Automated Rendezvous and Docking (AR&D). NASA video sensors have worked well in the past: the AVGS used on the Demonstration of Autonomous Rendezvous Technology (DART) mission operated successfully in "spot mode" out to 2 km, and the first generation rendezvous and docking sensor, the Video Guidance Sensor (VGS), was developed and successfully flown on Space Shuttle flights in 1997 and 1998. This paper presents the flight heritage and results of the sensor technology, some hardware trades for the current sensor, and discusses the needs of future vehicles that may rendezvous and dock with the International Space Station (ISS) and other Constellation vehicles. It also discusses approaches for upgrading AVGS to address parts obsolescence, and concepts for minimizing the sensor footprint, weight, and power requirements. In addition, the testing of the various NGAVGS development units will be discussed along with the use of the NGAVGS as a proximity operations and docking sensor.

  11. Super MI sensor: recent advances of amorphous wire and CMOS-IC magneto-impedance sensor.

    PubMed

    Mohri, Kaneo; Honkura, Yoshinobu; Panina, Larissa V; Uchiyama, Tsuyoshi

    2012-09-01

    We indicate that the Magneto-Impedance sensor using amorphous wires has reached a new stage to view "Super MI sensor technology" based on three main advantageous factors of (i) micro sized head and micro power consumption chip, (ii) ultra-high sensitivity micro magnetic sensor with 1 pico-Tesla resolution at the room temperature without any electromagnetic shielding, and (iii) ultra-quick response magnetic sensor with GHz operation. We summarize systematically the magneto-impedance technology with the basic principle and mechanisms of three advantageous features for constitution of various high performance new sensor devices such as the electronic compass chip for mobile phones and smart phones and portable sensors for the magneto-encephalography, the magneto-spinography, and various bio-cell magnetic measurements. Possibility of new application to MI antenna in magnetic telecommunications is also discussed. PMID:23035502

  12. The Next Generation Advanced Video Guidance Sensor: Flight Heritage and Current Development

    NASA Astrophysics Data System (ADS)

    Howard, Richard T.; Bryan, Thomas C.

    2009-03-01

    The Next Generation Advanced Video Guidance Sensor (NGAVGS) is the latest in a line of sensors that have flown four times in the last 10 years. The NGAVGS has been under development for the last two years as a long-range proximity operations and docking sensor for use in an Automated Rendezvous and Docking (AR&D) system. The first autonomous rendezvous and docking in the history of the U.S. Space Program was successfully accomplished by Orbital Express, using the Advanced Video Guidance Sensor (AVGS) as the primary docking sensor. That flight proved that the United States now has a mature and flight proven sensor technology for supporting Crew Exploration Vehicles (CEV) and Commercial Orbital Transport Systems (COTS) Automated Rendezvous and Docking (AR&D). NASA video sensors have worked well in the past: the AVGS used on the Demonstration of Autonomous Rendezvous Technology (DART) mission operated successfully in "spot mode" out to 2 km, and the first generation rendezvous and docking sensor, the Video Guidance Sensor (VGS), was developed and successfully flown on Space Shuttle flights in 1997 and 1998.

  13. EDITORIAL: Microwave Moisture Measurements

    NASA Astrophysics Data System (ADS)

    Kaatze, Udo; Kupfer, Klaus; Hübner, Christof

    2007-04-01

    Microwave moisture measurements refer to a methodology by which the water content of materials is non-invasively determined using electromagnetic fields of radio and microwave frequencies. Being the omnipresent liquid on our planet, water occurs as a component in most materials and often exercises a significant influence on their properties. Precise measurements of the water content are thus extremely useful in pure sciences, particularly in biochemistry and biophysics. They are likewise important in many agricultural, technical and industrial fields. Applications are broad and diverse, and include the quality assessment of foodstuffs, the determination of water content in paper, cardboard and textile production, the monitoring of moisture in sands, gravels, soils and constructions, as well as the measurement of water admixtures to coal and crude oil in reservoirs and in pipelines. Microwave moisture measurements and evaluations require insights in various disciplines, such as materials science, dielectrics, the physical chemistry of water, electrodynamics and microwave techniques. The cooperation of experts from the different fields of science is thus necessary for the efficient development of this complex discipline. In order to advance cooperation the Workshop on Electromagnetic Wave Interaction with Water and Moist Substances was held in 1993 in Atlanta. It initiated a series of international conferences, of which the last one was held in 2005 in Weimar. The meeting brought together 130 scientists and engineers from all over the world. This special issue presents a collection of some selected papers that were given at the event. The papers cover most topics of the conference, featuring dielectric properties of aqueous materials, electromagnetic wave interactions, measurement methods and sensors, and various applications. The special issue is dedicated to Dr Andrzej W Kraszewski, who died in July 2006 after a distinguished career of 48 years in the research of

  14. Early results of the soil moisture active passive Marena Oklahoma in situ sensor testbed (SMAP-MOISST)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil Moisture Active Passive Mission (SMAP) is an upcoming NASA mission to monitor surface soil mositure. Key to the success of this mission is the calibration and validation of the resulting product. As part of the calibration and validation program for SMAP, an ambitious intercomparison stud...

  15. MOISTURE CONTENT DETERMINATION OF IN-SHELL PEANUTS USING A LOW COST IMPEDANCE ANALYZER AND CAPACITOR SENSOR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Moisture content (MC) in peanuts is an important parameter to be measured and monitored at various stages in peanut industry. In previous research, the peanut MC was estimated by placing a sample between a set of parallel-plate conductors and capacitance and phase angle of the system using commerci...

  16. Twisted Pair Of Insulated Wires Senses Moisture

    NASA Technical Reports Server (NTRS)

    Laue, Eric G.; Stephens, James B.

    1989-01-01

    Sensitivity of electronic moisture sensor to low levels of moisture increased by new electrode configuration. Moisture-sensing circuit described in "Low-Cost Humidity Sensor" (NPO-16544). New twisted pair of wires takes place of flat-plate capacitor in circuit. Configuration allows for thermal expansion and contraction of polymer while maintaining nearly constant area of contact between polymer and wires.

  17. The AEDC aerospace chamber 7V: An advanced test capability for infrared surveillance and seeker sensors

    NASA Technical Reports Server (NTRS)

    Simpson, W. R.

    1994-01-01

    An advanced sensor test capability is now operational at the Air Force Arnold Engineering Development Center (AEDC) for calibration and performance characterization of infrared sensors. This facility, known as the 7V, is part of a broad range of test capabilities under development at AEDC to provide complete ground test support to the sensor community for large-aperture surveillance sensors and kinetic kill interceptors. The 7V is a state-of-the-art cryo/vacuum facility providing calibration and mission simulation against space backgrounds. Key features of the facility include high-fidelity scene simulation with precision track accuracy and in-situ target monitoring, diffraction limited optical system, NIST traceable broadband and spectral radiometric calibration, outstanding jitter control, environmental systems for 20 K, high-vacuum, low-background simulation, and an advanced data acquisition system.

  18. Precision moisture generation and measurement.

    SciTech Connect

    Thornberg, Steven Michael; White, Michael I.; Irwin, Adriane Nadine

    2010-03-01

    In many industrial processes, gaseous moisture is undesirable as it can lead to metal corrosion, polymer degradation, and other materials aging processes. However, generating and measuring precise moisture concentrations is challenging due to the need to cover a broad concentration range (parts-per-billion to percent) and the affinity of moisture to a wide range surfaces and materials. This document will discuss the techniques employed by the Mass Spectrometry Laboratory of the Materials Reliability Department at Sandia National Laboratories to generate and measure known gaseous moisture concentrations. This document highlights the use of a chilled mirror and primary standard humidity generator for the characterization of aluminum oxide moisture sensors. The data presented shows an excellent correlation in frost point measured between the two instruments, and thus provides an accurate and reliable platform for characterizing moisture sensors and performing other moisture related experiments.

  19. Advanced Layered Composite Polylaminate Electroactive Actuator and Sensor

    NASA Technical Reports Server (NTRS)

    Fox, Robert L. (Inventor); Hellbaum, Richard F. (Inventor); Copeland, Benjamin M., Jr. (Inventor); Bryant, Robert G. (Inventor)

    2000-01-01

    The present invention relates to the mounting of pre-stressed electroactive material in such a manner that large displacement actuators or sensors result. The invention comprises mounting the pre-stressed electroactive material to a support layer. This combination of a pre-stressed electroactive material and support layer may in turn be attached to a mounting surface. The pre-stressed electroactive material may be a ferroelectric, pyroelectric, piezoelectric, or magnetostrictive material. The size, stiffness, mass, and material of the support layer is selected to result in the electroactive device having dynamic response properties, environmental capability characteristics, and the required resilience optimized for a given application. The capacity to connect the support layer to a surface expands the arenas in which the prestressed electroactive device may be used. Application for which the invention may be used include actuators, sensors, or as a component in a pumps, switches, relays, pressure transducers and acoustic devices.

  20. Sensor-Only System Identification for Structural Health Monitoring of Advanced Aircraft

    NASA Technical Reports Server (NTRS)

    Kukreja, Sunil L.; Bernstein, Dennis S.

    2012-01-01

    Environmental conditions, cyclic loading, and aging contribute to structural wear and degradation, and thus potentially catastrophic events. The challenge of health monitoring technology is to determine incipient changes accurately and efficiently. This project addresses this challenge by developing health monitoring techniques that depend only on sensor measurements. Since actively controlled excitation is not needed, sensor-to-sensor identification (S2SID) provides an in-flight diagnostic tool that exploits ambient excitation to provide advance warning of significant changes. S2SID can subsequently be followed up by ground testing to localize and quantify structural changes. The conceptual foundation of S2SID is the notion of a pseudo-transfer function, where one sensor is viewed as the pseudo-input and another is viewed as the pseudo-output, is approach is less restrictive than transmissibility identification and operational modal analysis since no assumption is made about the locations of the sensors relative to the excitation.

  1. Advanced spectral fiber optic sensor systems and their application in energy facility monitoring

    NASA Astrophysics Data System (ADS)

    Willsch, Reinhardt; Ecke, Wolfgang; Bosselmann, Thomas; Willsch, Michael; Lindner, Eric; Bartelt, Hartmut

    2011-06-01

    Various spectral-encoded fiber optic sensor concepts and advanced system solutions for application in energy facility monitoring have been investigated. The technological maturity, high performance and reliability of multiplexed fiber Bragg grating (FBG) sensor arrays and networks for the measurement of temperature, dynamic strain, air flow, and magnetic field distributions in electric power generators increasing their efficiency will be demonstrated by selected examples of field testing under harsh environmental conditions. For high-temperature combustion monitoring in gas turbines, beside silica FBGs with enhanced temperature stability also sapphire FBGs and Fabry-Perot sensors have been tested and evaluated as well as fiber-based black-body thermal radiation sensors. Finally, the potential of FBG sensors for application in cryo-energetic facilities such as super-conductive high-power motors and experimental nuclear fusion reactors will be discussed.

  2. EDITORIAL: Advanced Sensors and Instrumentation Systems for the Food and Beverage Industries

    NASA Astrophysics Data System (ADS)

    Yan, Yong

    2006-02-01

    Advanced sensors and instrumentation systems are becoming increasingly important in the classification, characterization, authentication, quality control and safety management of food products and beverages. To bring together industrialists and academic researchers to discuss the latest developments and trends in this particular area, the ISAT (Instrument Science and Technology) Group of the Institute of Physics organized a highly focused one-day technical meeting, which was held at the Rutherford Conference Centre at the Institute of Physics in London on 15 December 2004. The event was co-sponsored by the Measurement, Sensors, Instrumentation and NDT Professional Network of the Institution of Electrical Engineers and the Measurement Science and Technology Panel of the Institute of Measurement and Control. The special feature in this issue (on pages 229 287) brings together a collection of some of the papers that were presented at the event. Also included in the special feature are two relevant papers that were submitted through the usual route. Technical topics covered, though wide ranging as reflected in part by the diversity of the papers, demonstrate recent developments and possible approaches that may offer solutions to a broad range of sensing and measurement problems in the food and beverage industries. The first paper, reported by Sheridan et al, is concerned with the quality monitoring of chicken, sausages and pastry products during their cooking processes using an optical fibre-based sensing system. Carter et al describe how digital imaging and image processing techniques have been applied to achieve the classification and authentication of rice grains. The challenges in the measurement and control of final moisture content in baked food products such as bread and biscuits are addressed and discussed by McFarlane. Juodeikiene et al report their progress in the development of acoustic echolocation-based techniques for the evaluation of porosity and

  3. New Sensors for the Advanced Test Reactor National Scientific User Facility

    SciTech Connect

    Joy L. Rempe; Darrell L. Knudson; Keith G. Condie; Joshua E. Daw; Heng Ban; Brandon Fox; Gordon Kohse

    2009-06-01

    A key component of the ATR NSUF effort is to develop and evaluate new in-pile instrumentation techniques that are capable of providing real-time measurements of key parameters during irradiation. This paper describes the selection strategy of what instrumentation is needed, and the program generated for developing new or enhanced sensors that can address these needs. Accomplishments from this program are illustrated by describing new sensors now available to users of the ATR NSUF with data from irradiation tests using these sensors. In addition, progress is reported on current research efforts to provide users advanced methods for detecting temperature, fuel thermal conductivity, and changes in sample geometry.

  4. Noninvasive sensors for in-situ process monitoring and control in advanced microelectronics manufacturing

    NASA Astrophysics Data System (ADS)

    Moslehi, Mehrdad M.

    1991-04-01

    The combination of noninvasive in-situ monitoring sensors single-wafer processing modules vacuum-integrated cluster tools and computer-integrated manufacturing (CIM) can provide a suitable fabrication environment for flexible and high-yield advanced semiconductor device manufacturing. The use of in-situ sensors for monitoring of equipment process and wafer parameters results in increased equipment/process up-time reduced process and device parameter spread improved cluster tool reliability and functionality and reduced overall device manufacturing cycle time. This paper will present an overview of the main features and impact of noninvasive in-situ monitoring sensors for semiconductor device manufacturing applications. Specific examples will be presented for the use of critical sensors in conjunction with cluster tools for advanced CMOS device processing. A noninvasive temperature sensor will be presented which can monitor true wafer temperature via infrared (5. 35 jtm) pyrometery and laser-assisted real-time spectral wafer emissivity measurements. This sensor design eliminates any. temperature measurement errors caused by the heating lamp radiation and wafer emissivity variations. 1. SENSORS: MOTIVATIONS AND IMPACT Semiconductor chip manufacturing factories usually employ well-established statistical process control (SPC) techniques to minimize the process parameter deviations and to increase the device fabrication yield. The conventional fabrication environments rely on controlling a limited set of critical equipment and process parameters (e. g. process pressure gas flow rates substrate temperature RF power etc. ) however most of the significant wafer process and equipment parameters of interest are not monitored in real

  5. Surface Soil Moisture Assimilation From ASAR Imagery for Root Zone Moisture Predictions at Basin Scale

    NASA Astrophysics Data System (ADS)

    Caschili, A.; Montaldo, N.; Mancini, M.; Albertson, J. D.; Botti, P.; Dessena, M. A.; Carboni, E.

    2003-12-01

    The state of the root-zone soil moisture is a key variable controlling surface water and energy balances. Emerging efforts in data assimilation seek to guide land surface models (LSMs) with periodic observations of surface soil moisture. Montaldo et al. (Water Resour. Res., 2001) and Montaldo and Albertson (Adv. Water Resour., 2003) developed an operational multi-scale assimilation system for robust root zone soil moisture predictions at the local scale. The assimilation scheme, developed for a force-restore method based LSM, updates the measured surface soil moisture, the root zone soil water content and the soil hydraulic conductivity, in a manner that compensates for both inaccurate initial conditions and model parameter estimates. In this presentation we describe the development and testing of an operational assimilation system for robust root-zone soil moisture predictions at the basin scale. High resolution data of the new ASAR (advanced synthetic aperture radar) sensor aboard European Space Agency's Envisat satellite offers the opportunity for monitoring surface soil moisture at high resolution (up to 30 m), which is suitable for distributed mapping within the small scales of typical Mediterranean basins. Indeed, adequate spatio-temporal monitoring of the soil moisture is essential to improve our capability to simulate the water balance. As part of a recently-approved European Space Agency (ESA) Envisat AO project, ASAR-based soil moisture mapping of the Mulargia basin (area of about 65 sq.km), sub-basin of the Flumendosa basin in Sardinia, are available . This semi-arid basin has a key role in the water resources management of Sardinia. Semi-arid regions, such as Sardinia island, suffers from water scarcity, which is increasingly due to the broad desertification processes of the Mediterranean area. Within the basin, land surface fluxes are well monitored through two evapotraspiration measurement systems (one eddy correlation technique based station, and one

  6. Composite magnetostrictive materials for advanced automotive magnetomechanical sensors

    NASA Astrophysics Data System (ADS)

    McCallum, R. W.; Dennis, K. W.; Jiles, D. C.; Snyder, J. E.; Chen, Y. H.

    2001-04-01

    In this paper we present the development of a composite magnetostrictive material for automotive applications. The material is based on cobalt ferrite, CoOṡFe2O3, and contains a small fraction of metallic matrix phase that serves both as a liquid-phase sintering aid during processing and enhances the mechanical properties over those of a simple sintered ferrite ceramic. In addition the metal matrix makes it possible to braze the material, making the assembly of a sensor relatively simple. The material exhibits good sensitivity and should have high corrosion resistance, while at the same time it is low in cost.

  7. Field test of a multi-frequency electromagnetic induction sensor for the study of soil moisture in different land-soil units

    NASA Astrophysics Data System (ADS)

    Calamita, Giuseppe; Onorati, Beniamino; Perrone, Angela; Manfreda, Salvatore; Brocca, Luca

    2015-04-01

    The crucial role of the soil moisture (SM) in a number of natural processes that act at different spatial and temporal scales has been largely recognized by the scientific community. Although the most used ground-based techniques for SM measurement (i.e. the Thermo-gravimentric, Time Domain Reflectometry (TDR) probes, Capacitance sensors, Neutron-moisture meters (NMM)) proved to be accurate and permit to acquire data at a high temporal resolution, they still remain invasive and punctual. As the size of the area of interest grows, these methods reveal applicability limitations that have been only partially overcome with the coming of the distributed sensor networks. During last decade, it has been pointed out that an improved understanding of the processes and factors that control SM patterns at non-punctual scales might result from information collected in larger volume of subsoil or larger study area. Indeed, sensing greater volumes of soil over larger areas would filter less important details that derive from a simple sum of multi-point measurements and would be useful to emphasize the characteristics emerging at larger scales. This implies the collection of measurements on a large number of points distributed over larger scales, although characterized by lower accuracy. Recently, geophysical methods have received special attention thanks to their ability to collect information that go beyond the local information sensed with traditional sensors. Between potentially useful methods, the Electro-Magnetic Induction (EMI) method has been indicated as one of the most promising for hydrological applications. Ground-based EMI sensors are lightweight, do not require contact with the soil allowing a considerable reduction of the survey costs as long as the spatial extent of the area of interest grows. Moreover, the ability to measure through thicknesses of soil greater than some centimetres and the possibility to collect data in wooded areas make the use of these sensors

  8. ADVANCED SOLID STATE SENSORS FOR VISION 21 SYSTEMS

    SciTech Connect

    C.D. Stinespring

    2005-04-28

    Silicon carbide (SiC) is a high temperature semiconductor with the potential to meet the gas and temperature sensor needs in both present and future power generation systems. These devices have been and are currently being investigated for a variety of high temperature sensing applications. These include leak detection, fire detection, environmental control, and emissions monitoring. Electronically these sensors can be very simple Schottky diode structures that rely on gas-induced changes in electrical characteristics at the metal-semiconductor interface. In these devices, thermal stability of the interfaces has been shown to be an essential requirement for improving and maintaining sensor sensitivity and lifetime. In this report, we describe device fabrication and characterization studies relevant to the development of SiC based gas and temperature sensors. Specifically, we have investigated the use of periodically stepped surfaces to improve the thermal stability of the metal semiconductor interface for simple Pd-SiC Schottky diodes. These periodically stepped surfaces have atomically flat terraces on the order of 200 nm wide separated by steps of 1.5 nm height. It should be noted that 1.5 nm is the unit cell height for the 6H-SiC (0001) substrates used in these studies. These surfaces contrast markedly with the ''standard'' SiC surfaces normally used in device fabrication. Obvious scratches and pots as well as subsurface defects characterize these standard surfaces. This research involved ultrahigh vacuum deposition and characterization studies to investigate the thermal stability of Pd-SiC Schottky diodes on both the stepped and standard surfaces, high temperature electrical characterization of these device structures, and high temperature electrical characterization of diodes under wet and dry oxidizing conditions. To our knowledge, these studies have yielded the first electrical characterization of actual sensor device structures fabricated under ultrahigh

  9. Advanced monolithic active pixel sensors for tracking, vertexing and calorimetry with full CMOS capability

    NASA Astrophysics Data System (ADS)

    Stanitzki, M.; SPiDeR Collaboration, www. spider. ac. uk

    2011-09-01

    We present test results from the "TPAC" and "F ORTIS" sensors produced using the 180 nm CMOS INMAPS process. The TPAC sensor has a 50 μm pixel size with advanced in-pixel electronics. Although TPAC was developed for digital electromagnetic calorimetry, the technology can be readily extended to tracking and vertexing applications where highly granular pixels with in-pixel intelligence are required. By way of example, a variant of the TPAC sensor has been proposed for the Super B vertex detector. The F ORTIS sensor is a prototype with several pixel variants to study the performance of a four transistors (4T) architecture and is the first sensor of this type tested for particle physics applications. TPAC and F ORTIS sensors have been fabricated with some of the processing innovations available in INMAPS such as deep p-wells and high-resistivity epitaxial layers. The performance of these sensor variants has been measured both in the laboratory and at test beams and results showing significant improvements due to these innovations are presented. We have recently manufactured the "C HERWELL" sensor, building on the experience with both TPAC and F ORTIS and making use of the 4T approach. C HERWELL is designed for tracking and vertexing and has an integrated ADC and targets very low-noise performance. The principal features of C HERWELL are described.

  10. Two-terminal longitudinal hotwire sensor for monitoring the position and speed of advancing liquid fronts in microfluidic channels

    SciTech Connect

    Ryu, Kee Suk; Shaikh, Kashan; Goluch, Edgar; Liu Chang

    2006-03-06

    We report a simple and practical sensor for monitoring both the absolute position and advancing speed of liquid front in a microfluidic channel. The sensor consists of a longitudinal hot wire element - a two-terminal electrical device, with its length spanning the entire channel. The design, materials, fabrication method, and use of this sensor are extremely simple. Characterization results are presented.

  11. Recent Advances in Nanoplasmonic Sensors for Environmental Detection and Monitoring.

    PubMed

    Choi, Inhee

    2016-05-01

    The great attention in environmental pollution urges the development of innovative monitoring system enabling rapid, sensitive, specific detection and easy operation. Recent progress in nanoplasmonic sensors allowing real-time, highly-sensitive, label-free and multiplex detection provides a promising alternative to conventional environmental analyzing techniques. This review summarizes novel nanoplasmonic approaches categorized by optical detection technologies, which include surface plasmon resonance spectroscopy, dark-field nanospectroscopy, Raman spectroscopy, and even naked eyes. The focus of this review will be on how plasmonic nanostructures can be utilized to detect environmental pollutants, and remarkable accomplishments to enhance the detection performances. In addition, we discuss current challenge and future direction for ubiquitous environmental sensing and monitoring. PMID:27483747

  12. Advanced array techniques for unattended ground sensor applications

    NASA Astrophysics Data System (ADS)

    Followill, Fred E.; Wolford, James K.; Candy, James V.

    1997-07-01

    Sensor arrays offer opportunities to beamform, and time- frequency analyses offer additional insights to the wavefield data. Data collected while monitoring three different sources with unattended ground sensors in a 16- element, small-aperture (approximately 5 meters) geophone array are used as examples of model-based seismic signal processing on actual geophone array data. The three sources monitored were: (Source 01). A frequency-modulated chirp of an electromechanical shaker mounted on a floor of an underground bunker. Three 60-second time-windows corresponding to (a) 50 Hz to 55 Hz sweep, (b) 60 Hz to 70 Hz sweep, and (c) 80 Hz to 90 Hz sweep. (Source 02). A single transient impact of a hammer striking the floor of the bunker. Twenty seconds of data (with the transient event approximately mid-point in the time window). (Source 11). The transient event of a diesel generator turning on, including a few seconds before the `turn-on time' and a few seconds after the generator reaches `steady-state conditions'. The high-frequency seismic array was positioned at the surface of the ground at a distance of 150 meters (North) of the underground bunker. Four Y-shaped subarrays (each with 2-meter apertures) in a Y-shaped pattern (with a 6-meter aperture) using a total of 163-component, high- frequency geophones were deployed. These 48 channels of seismic data were recorded at 6000 and 12000 samples per second on 16-bit data loggers. Representative examples of the data and analyses illustrate the results of this experiment.

  13. Advanced array techniques for unattended ground sensor applications

    SciTech Connect

    Followill, F.E.; Wolford, J.K.; Candy, J.V.

    1997-05-06

    Sensor arrays offer opportunities to beam form, and time-frequency analyses offer additional insights to the wavefield data. Data collected while monitoring three different sources with unattended ground sensors in a 16-element, small-aperture (approximately 5 meters) geophone array are used as examples of model-based seismic signal processing on actual geophone array data. The three sources monitored were: (Source 01). A frequency-modulated chirp of an electromechanical shaker mounted on the floor of an underground bunker. Three 60-second time-windows corresponding to (a) 50 Hz to 55 Hz sweep, (b) 60 Hz to 70 Hz sweep, and (c) 80 Hz to 90 Hz sweep. (Source 02). A single transient impact of a hammer striking the floor of the bunker. Twenty seconds of data (with the transient event approximately mid-point in the time window.(Source 11)). The transient event of a diesel generator turning on, including a few seconds before the turn-on time and a few seconds after the generator reaches steady-state conditions. The high-frequency seismic array was positioned at the surface of the ground at a distance of 150 meters (North) of the underground bunker. Four Y-shaped subarrays (each with 2-meter apertures) in a Y-shaped pattern (with a 6-meter aperture) using a total of 16 3-component, high-frequency geophones were deployed. These 48 channels of seismic data were recorded at 6000 and 12000 samples per second on 16-bit data loggers. Representative examples of the data and analyses illustrate the results of this experiment.

  14. Development of Micro Air Reconnaissance Vehicle as a Test Bed for Advanced Sensors and Electronics

    NASA Technical Reports Server (NTRS)

    Shams, Qamar A.; Vranas, Thomas L.; Fox, Robert L.; Kuhn, Theodore R.; Ingham, John; Logan, Michael J.; Barnes, Kevin N.; Guenther, Benjamin F.

    2002-01-01

    This paper describes the development of a Micro/Mini Air Reconnaissance Vehicle for advanced sensors and electronics at NASA Langley Research Center over the last year. This vehicle is expected to have a total weight of less than four pounds, a design velocity of 40 mph, an endurance of 15-20 minutes, and a maximum range of 5km. The vehicle has wings that are simple to detach yet retain the correct alignment. The upper fuselage surface has a quick release hatch used to access the interior and also to mount the varying propulsion systems. The sensor suite developed for this vehicle consists of a Pitot-static measurement system for determining air speed, an absolute pressure measurement for determining altitude, magnetic direction measurement, and three orthogonal gyros to determine body angular rates. Swarming GPS-guidance and in-flight maneuvering is discussed, as well as design and installation of some other advance sensors like MEMS microphones, infrared cameras, GPS, humidity sensors, and an ultrasonic sonar sensor. Also low cost, small size, high performance control and navigation system for the Micro Air Vehicle is discussed. At the end, laboratory characterization of different sensors, motors, propellers, and batteries will be discussed.

  15. Performance of an Advanced Stirling Convertor Based on Heat Flux Sensor Measurements

    NASA Technical Reports Server (NTRS)

    Wilson, Dcott D.

    2012-01-01

    The U.S. Department of Energy (DOE) and Lockheed Martin Space Systems Company (LMSSC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. This generator would use two highefficiency Advanced Stirling Convertors (ASCs), developed by Sunpower, Inc., and NASA Glenn Research Center. The ASCs convert thermal energy from a radioisotope heat source into electricity. As part of ground testing of these ASCs, different operating conditions are used to simulate expected mission conditions. These conditions require achieving a particular operating frequency, hot-end and cold-end temperatures, and specified electrical power output for a given heat input. It is difficult to measure heat input to Stirling convertors due to the complex geometries of the hot components, temperature limits of sensor materials, and invasive integration of sensors. A thin-film heat flux sensor was used to directly measure heat input to an ASC. The effort succeeded in designing and fabricating unique sensors, which were integrated into a Stirling convertor ground test and exposed to test temperatures exceeding 700 C in air for 10,000 hr. Sensor measurements were used to calculate thermal efficiency for ASC-E (Engineering Unit) #1 and #4. The post-disassembly condition of the sensors is also discussed.

  16. Performance of an Advanced Stirling Convertor Based on Heat Flux Sensor Measurements

    NASA Technical Reports Server (NTRS)

    Wilson, Scott D.

    2012-01-01

    The U.S. Department of Energy (DOE) and Lockheed Martin Space Systems Company (LMSSC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. This generator would use two high-efficiency Advanced Stirling Convertors (ASCs), developed by Sunpower, Inc., and NASA Glenn Research Center. The ASCs convert thermal energy from a radioisotope heat source into electricity. As part of ground testing of these ASCs, different operating conditions are used to simulate expected mission conditions. These conditions require achieving a particular operating frequency, hot-end and cold-end temperatures, and specified electrical power output for a given heat input. It is difficult to measure heat input to Stirling convertors due to the complex geometries of the hot components, temperature limits of sensor materials, and invasive integration of sensors. A thin-film heat flux sensor was used to directly measure heat input to an ASC. The effort succeeded in designing and fabricating unique sensors, which were integrated into a Stirling convertor ground test and exposed to test temperatures exceeding 700 C in air for 10,000 hr. Sensor measurements were used to calculate thermal efficiency for ASC-E (Engineering Unit) #1 and #4. The post-disassembly condition of the sensors is also discussed.

  17. Estimating crop production in Iowa from Advanced Wide Field Sensor (AWiFS) data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Indian National Remote Sensing Agency ResourceSat-1 Advanced Wide Field Sensor (AWiFS) data for the USA is being provided online by the USDA Foreign Agricultural Service (FAS) and Arctic Slope Regional Corporation – Management Services (ASRC-MS). Because of the frequent revisit time and pixel sizes...

  18. NASA Programs in Advanced Sensors and Measurement Technology for Aeronautical Applications

    NASA Technical Reports Server (NTRS)

    Conway, Bruce A.

    2004-01-01

    There are many challenges facing designers and operators of our next-generation aircraft in meeting the demands for efficiency, safety, and reliability which are will be imposed. This paper discusses aeronautical sensor requirements for a number of research and applications areas pertinent to the demands listed above. A brief overview will be given of aeronautical research measurements, along with a discussion of requirements for advanced technology. Also included will be descriptions of emerging sensors and instrumentation technology which may be exploited for enhanced research and operational capabilities. Finally, renewed emphasis of the National Aeronautics and Space Administration in advanced sensor and instrumentation technology development will be discussed, including project of technology advances over the next 5 years. Emphasis on NASA efforts to more actively advance the state-of-the-art in sensors and measurement techniques is timely in light of exciting new opportunities in airspace development and operation. An up-to-date summary of the measurement technology programs being established to respond to these opportunities is provided.

  19. Advanced turbine systems sensors and controls needs assessment study. Final report

    SciTech Connect

    Anderson, R.L.; Fry, D.N.; McEvers, J.A.

    1997-02-01

    The Instrumentation and Controls Division of the Oak Ridge National Laboratory performed an assessment of the sensors and controls needs for land-based advanced gas turbines being designed as a part of the Department of Energy`s (DOE`s) Advanced Turbine Systems (ATS) Program for both utility and industrial applications. The assessment included visits to five turbine manufacturers. During these visits, in-depth discussions were held with design and manufacturing staff to obtain their views regarding the need for new sensors and controls for their advanced turbine designs. The Unsteady Combustion Facilities at the Morgantown Energy Technology Center was visited to assess the need for new sensors for gas turbine combustion research. Finally, a workshop was conducted at the South Carolina Energy Research and Development Center which provided a forum for industry, laboratory, and university engineers to discuss and prioritize sensor and control needs. The assessment identified more than 50 different measurement, control, and monitoring needs for advanced turbines that cannot currently be met from commercial sources. While all the identified needs are important, some are absolutely critical to the success of the ATS Program.

  20. Final Report - ADVANCED LASER-BASED SENSORS FOR INDUSTRIAL PROCESS CONTROL

    SciTech Connect

    Gupta, Manish; Baer, Douglas

    2013-09-30

    The objective of this work is to capture the potential of real-time monitoring and overcome the challenges of harsh industrial environments, Los Gatos Research (LGR) is fabricating, deploying, and commercializing advanced laser-based gas sensors for process control monitoring in industrial furnaces (e.g. electric arc furnaces). These sensors can achieve improvements in process control, leading to enhanced productivity, improved product quality, and reduced energy consumption and emissions. The first sensor will utilize both mid-infrared and near-infrared lasers to make rapid in-situ measurements of industrial gases and associated temperatures in the furnace off-gas. The second sensor will make extractive measurements of process gases. During the course of this DOE project, Los Gatos Research (LGR) fabricated, tested, and deployed both in-situ tunable diode laser absorption spectrometry (TDLAS) analyzers and extractive Off-Axis Integrated Cavity Output Spectroscopy (Off-Axis ICOS) analyzers.

  1. Diagnosis of Thermal Efficiency of Advanced Combined Cycle Power Plants Using Optical Torque Sensors

    NASA Astrophysics Data System (ADS)

    Umezawa, Shuichi

    A new optical torque measurement method was applied to diagnosis of thermal efficiency of advanced combined cycle, i.e. ACC, plants. Since the ACC power plant comprises a steam turbine and a gas turbine and both of them are connected to the same generator, it is difficult to identify which turbine in the plant deteriorates the performance when the plant efficiency is reduced. The sensor measures axial distortion caused by power transmission by use of He-Ne laser beams, small stainless steel reflectors having bar-code patterns, and a technique of signal processing featuring high frequency. The sensor was applied to the ACC plants of TOKYO ELECTRIC POWER COMPANY, TEPCO, following the success in the application to the early combined cycle plants of TEPCO. The sensor performance was inspected over a year. After an improvement related to the signal process, it is considered that the sensor performance has reached a practical use level.

  2. Advanced data visualization and sensor fusion: Conversion of techniques from medical imaging to Earth science

    NASA Technical Reports Server (NTRS)

    Savage, Richard C.; Chen, Chin-Tu; Pelizzari, Charles; Ramanathan, Veerabhadran

    1993-01-01

    Hughes Aircraft Company and the University of Chicago propose to transfer existing medical imaging registration algorithms to the area of multi-sensor data fusion. The University of Chicago's algorithms have been successfully demonstrated to provide pixel by pixel comparison capability for medical sensors with different characteristics. The research will attempt to fuse GOES (Geostationary Operational Environmental Satellite), AVHRR (Advanced Very High Resolution Radiometer), and SSM/I (Special Sensor Microwave Imager) sensor data which will benefit a wide range of researchers. The algorithms will utilize data visualization and algorithm development tools created by Hughes in its EOSDIS (Earth Observation SystemData/Information System) prototyping. This will maximize the work on the fusion algorithms since support software (e.g. input/output routines) will already exist. The research will produce a portable software library with documentation for use by other researchers.

  3. Spatio-temporal interpolation of soil moisture in 3D+T using automated sensor network data

    NASA Astrophysics Data System (ADS)

    Gasch, C.; Hengl, T.; Magney, T. S.; Brown, D. J.; Gräler, B.

    2014-12-01

    Soil sensor networks provide frequent in situ measurements of dynamic soil properties at fixed locations, producing data in 2- or 3-dimensions and through time (2D+T and 3D+T). Spatio-temporal interpolation of 3D+T point data produces continuous estimates that can then be used for prediction at unsampled times and locations, as input for process models, and can simply aid in visualization of properties through space and time. Regression-kriging with 3D and 2D+T data has successfully been implemented, but currently the field of geostatistics lacks an analytical framework for modeling 3D+T data. Our objective is to develop robust 3D+T models for mapping dynamic soil data that has been collected with high spatial and temporal resolution. For this analysis, we use data collected from a sensor network installed on the R.J. Cook Agronomy Farm (CAF), a 37-ha Long-Term Agro-Ecosystem Research (LTAR) site in Pullman, WA. For five years, the sensors have collected hourly measurements of soil volumetric water content at 42 locations and five depths. The CAF dataset also includes a digital elevation model and derivatives, a soil unit description map, crop rotations, electromagnetic induction surveys, daily meteorological data, and seasonal satellite imagery. The soil-water sensor data, combined with the spatial and temporal covariates, provide an ideal dataset for developing 3D+T models. The presentation will include preliminary results and address main implementation strategies.

  4. Smart image sensors: an emerging key technology for advanced optical measurement and microsystems

    NASA Astrophysics Data System (ADS)

    Seitz, Peter

    1996-08-01

    Optical microsystems typically include photosensitive devices, analog preprocessing circuitry and digital signal processing electronics. The advances in semiconductor technology have made it possible today to integrate all photosensitive and electronical devices on one 'smart image sensor' or photo-ASIC (application-specific integrated circuits containing photosensitive elements). It is even possible to provide each 'smart pixel' with additional photoelectronic functionality, without compromising the fill factor substantially. This technological capability is the basis for advanced cameras and optical microsystems showing novel on-chip functionality: Single-chip cameras with on- chip analog-to-digital converters for less than $10 are advertised; image sensors have been developed including novel functionality such as real-time selectable pixel size and shape, the capability of performing arbitrary convolutions simultaneously with the exposure, as well as variable, programmable offset and sensitivity of the pixels leading to image sensors with a dynamic range exceeding 150 dB. Smart image sensors have been demonstrated offering synchronous detection and demodulation capabilities in each pixel (lock-in CCD), and conventional image sensors are combined with an on-chip digital processor for complete, single-chip image acquisition and processing systems. Technological problems of the monolithic integration of smart image sensors include offset non-uniformities, temperature variations of electronic properties, imperfect matching of circuit parameters, etc. These problems can often be overcome either by designing additional compensation circuitry or by providing digital correction routines. Where necessary for technological or economic reasons, smart image sensors can also be combined with or realized as hybrids, making use of commercially available electronic components. It is concluded that the possibilities offered by custom smart image sensors will influence the design

  5. The Advanced Video Guidance Sensor: Orbital Express and the Next Generation

    NASA Technical Reports Server (NTRS)

    Howard, Richard T.; Heaton, Andrew F.; Pinson, Robin M.; Carrington, Connie L.; Lee, James E.; Bryan, Thomas C.; Robertson, Bryan A.; Spencer, Susan H.; Johnson, Jimmie E.

    2008-01-01

    The Orbital Express (OE) mission performed the first autonomous rendezvous and docking in the history of the United States on May 5-6, 2007 with the Advanced Video Guidance Sensor (AVGS) acting as one of the primary docking sensors. Since that event, the OE spacecraft performed four more rendezvous and docking maneuvers, each time using the AVGS as one of the docking sensors. The Marshall Space Flight Center's (MSFC's) AVGS is a nearfield proximity operations sensor that was integrated into the Autonomous Rendezvous and Capture Sensor System (ARCSS) on OE. The ARCSS provided the relative state knowledge to allow the OE spacecraft to rendezvous and dock. The AVGS is a mature sensor technology designed to support Automated Rendezvous and Docking (AR&D) operations. It is a video-based laser-illuminated sensor that can determine the relative position and attitude between itself and its target. Due to parts obsolescence, the AVGS that was flown on OE can no longer be manufactured. MSFC has been working on the next generation of AVGS for application to future Constellation missions. This paper provides an overview of the performance of the AVGS on Orbital Express and discusses the work on the Next Generation AVGS (NGAVGS).

  6. Soil Moisture Estimation Across Scales with Mobile Sensors for Cosmic-Ray Neutrons from the Ground and Air

    NASA Astrophysics Data System (ADS)

    Schrön, Martin; Köhler, Mandy; Bannehr, Lutz; Köhli, Markus; Fersch, Benjamin; Rebmann, Corinna; Mai, Juliane; Cuntz, Matthias; Kögler, Simon; Schröter, Ingmar; Wollschläger, Ute; Oswald, Sascha; Dietrich, Peter; Zacharias, Steffen

    2016-04-01

    Soil moisture is a key variable for environmental sciences, but its determination at various scales and depths is still an open challenge. Cosmic-ray neutron sensing has become a well accepted and unique method to monitor an effective soil water content, covering tens of hectares in area and tens of centimeters in depth. The technology is famous for its low maintanance, non-invasiveness, continous measurement, and most importantly its large footprint and penetration depth. Beeing more representative than point data, and finer resolved plus deeper penetrating than remote-sensing products, cosmic-ray neutron derived soil moisture products provide unrivaled advantage for agriculture, regional hydrologic and land surface models. The method takes advantage of omnipresent neutrons which are extraordinarily sensitive to hydrogen in soil, plants, snow and air. Unwanted hydrogen sources in the footprint can be excluded by local calibration to extract the pure soil water information. However, this procedure is not feasible for mobile measurements, where neutron detectors are mounted on a car to do catchment-scale surveys. As a solution to that problem, we suggest strategies to correct spatial neutron data with the help of available spatial data of soil type, landuse and vegetation. We further present results of mobile rover campaigns at various scales and conditions, covering small sites from 0.2 km2 to catchments of 100 km2 area, and complex terrain from agricultural fields, urban areas, forests, to snowy alpine sites. As the rover is limited to accessible roads, we further investigated the applicability of airborne measurements. First tests with a gyrocopter at 150 to 200m heights proofed the concept of airborne neutron detection for environmental sciences. Moreover, neutron transport simulations confirm an improved areal coverage during these campaigns. Mobile neutron measurements at the ground or air are a promising tool for the detection of water sources across many

  7. Moisturizer Allergy

    PubMed Central

    Stechschulte, Sarah A.

    2008-01-01

    Background: Moisturizers are used by patients with dry skin conditions as well as those with healthy skin to enhance and preserve the smoothness of the skin and to interrupt the dry-skin cycle. Moisturizers are generally considered safe, although skin reactions, such as allergic contact dermatitis from topical preparations may occur. Cosmetic products including moisturizers are among the main culprits of allergic contact dermatitis. Methods: Utilizing a recently published database of all moisturizers available at Walgreens Pharmacies (Chicago, Illinois), which listed each product's allergens from the North American Contact Dermatitis Group (NACDG) screening panel, we evaluated the number of moisturizers containing each allergen. Results: Of the 276 moisturizers accounted for in the database, 68 percent contained fragrance making it the most common allergen found in these moisturizers. Parabens were discovered in 62 percent of moisturizers, followed by Vitamin E in 55 percent of products. Essential oils and biologic additives were found in 45 percent of products, followed by benzyl alcohol in 24 percent of moisturizers. Propylene glycol was found in 20 percent of moisturizers, followed by formaldehyde releasers in 20 percent of products. Iodopropynyl butylcarbamate was discovered in 16 percent of products, followed by lanolin in 10 percent of moisturizers. Methylisothiazolinone/methylchloroisothiazolinone was found in six percent of available products. Conclusions: Many ingredients of moisturizers have the potential to cause irritant and allergic contact dermatitis; therefore, it is necessary for clinicians to be aware of such potential allergens in order to manage and advise their patients accordingly. PMID:21212847

  8. Soil Moisture Workshop

    NASA Technical Reports Server (NTRS)

    Heilman, J. L. (Editor); Moore, D. G. (Editor); Schmugge, T. J. (Editor); Friedman, D. B. (Editor)

    1978-01-01

    The Soil Moisture Workshop was held at the United States Department of Agriculture National Agricultural Library in Beltsville, Maryland on January 17-19, 1978. The objectives of the Workshop were to evaluate the state of the art of remote sensing of soil moisture; examine the needs of potential users; and make recommendations concerning the future of soil moisture research and development. To accomplish these objectives, small working groups were organized in advance of the Workshop to prepare position papers. These papers served as the basis for this report.

  9. Assessment of fiber optic sensors and other advanced sensing technologies for nuclear power plants

    SciTech Connect

    Hashemian, H.M.

    1996-03-01

    As a result of problems such as calibration drift in nuclear plant pressure sensors and the recent oil loss syndrome in some models of Rosemount pressure transmitters, the nuclear industry has become interested in fiber optic pressure sensors. Fiber optic sensing technologies have been considered for the development of advanced instrumentation and control (I&C) systems for the next generation of reactors and in older plants which are retrofitted with new I&C systems. This paper presents the results of a six-month Phase I study to establish the state-of-the-art in fiber optic pressure sensing. This study involved a literature review, contact with experts in the field, an industrial survey, a site visit to a fiber optic sensor manufacturer, and laboratory testing of a fiber optic pressure sensor. The laboratory work involved both static and dynamic performance tests. This initial Phase I study has recently been granted a two-year extension by the U.S. Nuclear Regulatory Commission (NRC). The next phase will evaluate fiber optic pressure sensors in specific nuclear plant applications in addition to other advanced methods for monitoring critical nuclear plant equipment.

  10. Measurement of soil moisture using remote sensing multisensor radiation techniques

    NASA Technical Reports Server (NTRS)

    Waite, W. P. (Principal Investigator)

    1982-01-01

    Theoretical modeling as well as laboratory and field measurement were coupled with analysis of aircraft data obtained from controlled sites in an effort to enhance understanding of the microwave response due to soil moisture so as to specify sensor parameters and develop inversion algorithms. Models to predict the complex dielectric constant were produced which led to the interpretation of the results in terms of a matrix potential rather than simply moisture content. Similar advances were made in the development of coherent and incoherent radiative transfer models and rough surface scattering models.

  11. Application of artificial neural networks for the soil moisture retrieval from active and passive microwave spaceborne sensors

    NASA Astrophysics Data System (ADS)

    Santi, Emanuele; Paloscia, Simonetta; Pettinato, Simone; Fontanelli, Giacomo

    2016-06-01

    Among the algorithms used for the retrieval of SMC from microwave sensors (both active, such as Synthetic Aperture Radar-SAR, and passive, radiometers), the artificial neural networks (ANN) represent the best compromise between accuracy and computation speed. ANN based algorithms have been developed at IFAC, and adapted to several radar and radiometric satellite sensors, in order to generate SMC products at a resolution varying from hundreds of meters to tens of kilometers according to the spatial scale of each sensor. These algorithms, which are based on the ANN techniques for inverting theoretical and semi-empirical models, have been adapted to the C- to Ka- band acquisitions from spaceborne radiometers (AMSR-E/AMSR2), SAR (Envisat/ASAR, Cosmo-SkyMed) and real aperture radar (MetOP ASCAT). Large datasets of co-located satellite acquisitions and direct SMC measurements on several test sites worldwide have been used along with simulations derived from forward electromagnetic models for setting up, training and validating these algorithms. An overall quality assessment of the obtained results in terms of accuracy and computational cost was carried out, and the main advantages and limitations for an operational use of these algorithms were evaluated. This technique allowed the retrieval of SMC from both active and passive satellite systems, with accuracy values of about 0.05 m3/m3 of SMC or better, thus making these applications compliant with the usual accuracy requirements for SMC products from space.

  12. Advanced detection, isolation and accommodation of sensor failures: Real-time evaluation

    NASA Technical Reports Server (NTRS)

    Merrill, Walter C.; Delaat, John C.; Bruton, William M.

    1987-01-01

    The objective of the Advanced Detection, Isolation, and Accommodation (ADIA) Program is to improve the overall demonstrated reliability of digital electronic control systems for turbine engines by using analytical redundacy to detect sensor failures. The results of a real time hybrid computer evaluation of the ADIA algorithm are presented. Minimum detectable levels of sensor failures for an F100 engine control system are determined. Also included are details about the microprocessor implementation of the algorithm as well as a description of the algorithm itself.

  13. Advanced detection, isolation, and accommodation of sensor failures - Real-time evaluation

    NASA Technical Reports Server (NTRS)

    Merrill, Walter C.; Delaat, John C.; Bruton, William M.

    1988-01-01

    The objective of the Advanced Detection, Isolation, and Accommodation (ADIA) program is to improve the overall demonstrated reliability of digital electronic control systems for turbine engines by using analytical redundancy to detect sensor failures. The results of a real-time hybrid computer evaluation of the ADIA algorithm are presented. Minimum detectable levels of sensor failures for an F100 engine control system are determined. Also included are details about the microprocessor implementation of the algorithm as well as a description of the algorithm itself.

  14. Multiplexed Optical Fiber Sensors for Coal Fired Advanced Fossil Energy Systems

    SciTech Connect

    Wang, Anbo; Pickrell, Gary

    2012-03-31

    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. At the start of the project, the technical requirements for the sensing technology were determined together with our industrial partner Alstom Power. As is demonstrated in Chapter 4, all the technical requirements are successfully met. The success of the technology extended beyond laboratory test; its capability was further validated through the field test at DOE NETL, in which the sensors yielded distributed temperature mapping of a testing coupon installed in the turbine test rig. The measurement results agreed well with prior results generated with thermocouples. In this project, significant improvements were made to the IFPI sensor technology by splicing condition optimization, transmission loss reduction, sensor signal demodulation and sensor system design.

  15. Presentation of silicon platforms for wireless advanced networks of sensors for aeronautics application

    NASA Astrophysics Data System (ADS)

    Moreau, K.; Ruby, C.; Rolet, S.; Petitjean, B.; Rouet, V.

    2007-05-01

    The MEDEA+ SWANS (Silicon Platform for Wireless Advanced Networks of Sensors) project aims at defining a generic silicon platform, integrating analogue and digital Intellectual Property (IP) blocks for wireless sensor nodes technology. This generic platform will be used in various applications, such as transportation (aeronautics, automotive), homeland security, environmental and health/fitness. In the aeronautical application, the platform monitors, continuously, aircraft structures to detect whether a crack exists or not and process the data in real time, inside the platform. Measurements are provided by an inductive sensor glued on a structure and are acquired during flights. The sensor impedance (real and imaginary parts) varies depending on the state of the part area on which it is stuck. For example, this sensor aims at monitoring the further evolution of the crack too. The data are transmitted from the sensor to an ARM microcontroller through an electronic conditioner. Then, they are analysed and stored in a non volatile memory. Data measurements are collected by a RF transmission, every 2 or 4 months. A 3D stack platform demonstrator that allows the use of different technologies, will be realised, fully tested and characterised.

  16. Networked sensors for the future force (NSFF) advanced technology demonstration (ATD) communications systems

    NASA Astrophysics Data System (ADS)

    Nemeroff, Jay; DiPierro, Stefano

    2005-05-01

    The U.S. Army"s Future Combat Systems (FCS) and Future Force Warrior (FFW) will rely on the use of unattended, tactical sensors to detect and identify enemy targets in order to avoid enemy fires and enable precise networked fire to survive on the future battlefield with less armor protection. Successful implementation of these critical sensor fields requires the development of a specialized communications network infrastructure needed to disseminate sensor data to provide relevant, timely and accurate situational awareness information to the tactical common operating picture. The sensor network communications must support both static deployed and mobile ground and air robotic sensor arrays with robust, secure, stealthy, and jam resistant links. It is envisioned that tactical sensor networks can be deployed in a two tiered communications architecture that includes a lower sensor sub-layer consisting of acoustic, magnetic, Chemical/Biological and seismic detectors and an upper sub-layer consisting of infrared or visual imaging cameras. The upper sub-layer can be cued by the lower sub-layer and provides a seamless gateway link to higher echelon backbone tactical networks. The NSFF Advanced Technology Demonstration (ATD) communications effort focuses on providing Future Force systems such as the FCS and the Future Force Warrior with critical situational awareness data needed for survivability. The communications systems supporting this functionality must be designed such that unattended ground sensor data can flow seamlessly from the lowest unattended tactical sensor echelons into the Army"s tactical backbone networks while also allowing the "fusing" of the data with other intelligence information for correlation within a tactical command and control node. NSFF is realizing this capability by using advanced communications technologies developed under the Soldier Level Integrated Communications Environment (SLICE) Soldier Radio Waveform (SRW) project. These technologies

  17. Evaluation of three different data fusion approaches that uses satellite soil moisture from different passive microwave sensors to construct one consistent climate record

    NASA Astrophysics Data System (ADS)

    van der Schalie, Robin; de Jeu, Richard; Kerr, Yann; Wigneron, Jean-Pierre; Rodríguez-Fernández, Nemesio; Al-Yaari, Amen; Drusch, Matthias; Mecklenburg, Susanne; Dolman, Han

    2016-04-01

    -CCI-SM dataset. This recommendation is based on a series of statistical metrics (i.e. correlation, unbiased root mean square error, bias, spatial correspondence and single to noise ratios (Gruber et al., 2015)) and will provide guidelines for a seamless integration. References Al-Yaari, A., Wigneron, J.P., Kerr, Y., De Jeu, R.A.M., Rodriguez-Fernandez, N., Van der Schalie, R., Al Bitar, A., Mialon, A., Richaume, P., Dolman, A., and Ducharne, A. (2015), "Testing regression equations to derive long-term global soil moisture datasets from passive microwave observations", Remote Sensing of Environment, IN PRESS. Gruber, A., Su, C.-H., Zwieback, S., Crowd, W., Dorigo, W., and Wagner, W. (2015), "Recent advances in (soil moisture) triple collocation analysis", Int. J. Appl. Earth Observ. Geoinf, doi: http://dx.doi.org/10.1016/j.jag.2015.09.002. Kerr, Y.H., Waldteufel, P., Wigneron, J.P., Delwart, S., Cabot, F., Boutin, J., Escorihuela, M.J., Font, J., Reul, N., Gruhier, C., Juglea, S.E., Drinkwater, M.R., Hahne, A., Martin-Neira, M., and Mecklenburg, S. (2010), "The SMOS mission: New tool for monitoring key elements of the global water cycle", Proceedings of the IEEE, vol. 98, no. 5, doi: 10.1109/JPROC.2010.2043043. Rodríguez-Fernández, N.J., Aires, F., Richaume, P., Kerr, Y.H., Prigent, C., Kolassa, J., Cabot, F., Jiménez, C., Mahmoodi, A., and Drusch, M. (2015), "Soil Moisture Retrieval Using Neural Networks: Application to SMOS", IEEE Trans. on Geosc. and Remote Sens., vol. 53, no. 11, doi: 10.1109/TGRS.2015.2430845. Van der Schalie, R., Kerr, Y.H., Wigneron, J.P., Rodriguez-Fernandez, N.J., Al-Yaari, A., and De Jeu, R.A.M. (2015), "Global SMOS Soil Moisture Retrievals from The Land Parameter Retrieval Model", Int. J. Appl. Earth Observ. Geoinf, doi: http://dx.doi.org/10.1016/j.jag.2015.08.005. Wigneron J.-P., Calvet, J.-C., De Rosnay, P., Kerr, Y., Waldteufel, P., Saleh, K., Escorihuela, M.J. and Kruszewski, A. (2004), "Soil Moisture Retrievals from Bi-Angular L-band Passive

  18. Evaluation of three different data fusion approaches that uses satellite soil moisture from different passive microwave sensors to construct one consistent climate record

    NASA Astrophysics Data System (ADS)

    van der Schalie, Robin; de Jeu, Richard; Kerr, Yann; Wigneron, Jean-Pierre; Rodríguez-Fernández, Nemesio; Al-Yaari, Amen; Drusch, Matthias; Mecklenburg, Susanne; Dolman, Han

    2016-04-01

    -CCI-SM dataset. This recommendation is based on a series of statistical metrics (i.e. correlation, unbiased root mean square error, bias, spatial correspondence and single to noise ratios (Gruber et al., 2015)) and will provide guidelines for a seamless integration. References Al-Yaari, A., Wigneron, J.P., Kerr, Y., De Jeu, R.A.M., Rodriguez-Fernandez, N., Van der Schalie, R., Al Bitar, A., Mialon, A., Richaume, P., Dolman, A., and Ducharne, A. (2015), "Testing regression equations to derive long-term global soil moisture datasets from passive microwave observations", Remote Sensing of Environment, IN PRESS. Gruber, A., Su, C.-H., Zwieback, S., Crowd, W., Dorigo, W., and Wagner, W. (2015), "Recent advances in (soil moisture) triple collocation analysis", Int. J. Appl. Earth Observ. Geoinf, doi: http://dx.doi.org/10.1016/j.jag.2015.09.002. Kerr, Y.H., Waldteufel, P., Wigneron, J.P., Delwart, S., Cabot, F., Boutin, J., Escorihuela, M.J., Font, J., Reul, N., Gruhier, C., Juglea, S.E., Drinkwater, M.R., Hahne, A., Martin-Neira, M., and Mecklenburg, S. (2010), "The SMOS mission: New tool for monitoring key elements of the global water cycle", Proceedings of the IEEE, vol. 98, no. 5, doi: 10.1109/JPROC.2010.2043043. Rodríguez-Fernández, N.J., Aires, F., Richaume, P., Kerr, Y.H., Prigent, C., Kolassa, J., Cabot, F., Jiménez, C., Mahmoodi, A., and Drusch, M. (2015), "Soil Moisture Retrieval Using Neural Networks: Application to SMOS", IEEE Trans. on Geosc. and Remote Sens., vol. 53, no. 11, doi: 10.1109/TGRS.2015.2430845. Van der Schalie, R., Kerr, Y.H., Wigneron, J.P., Rodriguez-Fernandez, N.J., Al-Yaari, A., and De Jeu, R.A.M. (2015), "Global SMOS Soil Moisture Retrievals from The Land Parameter Retrieval Model", Int. J. Appl. Earth Observ. Geoinf, doi: http://dx.doi.org/10.1016/j.jag.2015.08.005. Wigneron J.-P., Calvet, J.-C., De Rosnay, P., Kerr, Y., Waldteufel, P., Saleh, K., Escorihuela, M.J. and Kruszewski, A. (2004), "Soil Moisture Retrievals from Bi-Angular L-band Passive

  19. A field evaluation of remote sensor measurements of wind, temperature, and moisture for ARM integrated sounding system research

    SciTech Connect

    Martner, B.E.; Westwater, E.R.; Strauch, R.G.

    1993-10-01

    Remote sensing systems were operated in Colorado in February and March 1991 to obtain detailed profiles of the kinematic and thermodynamic structure of the atmosphere for the US Department of Energy`s Atmospheric Radiation Measurement (ARM) research program. The instruments included wind profilers, Radio Acoustic Sounding Systems (PASS), microwave and infrared radiometers, an infrared spectrometer, ceilometers, radiosondes, surface meteorological stations, and other equipment. A mesoscale data assimilation model will be used to combine the data into dynamically consistent four-dimensional fields as part of an integrated data assimilation sounding system. This report evaluates the performance of the NOAA remote sensors used in the 1991 field data collection. These included five different wind profilers, each equipped with RASS capability for temperature profiling, and microwave radiometers for measurements of pathintegrated water vapor and liquid water content. The design and initial testing of a Fourier-transform InfraRed Sounder (FIRS) for humidity profiling is also described. The ranges of height coverage and measurement accuracies for each wind profiler/RASS are examined. Specific recommendations for optimizing the design and configuration of similar instruments are made for the ARM cloud and Radiation Testbed (CART) sites, based on results of the 1991 field work and earlier tests. Examples of routine processed data products are presented for three intensive operating period studies to further illustrate the remote sensors` capabilities.

  20. Mycotoxin Determination in Foods Using Advanced Sensors Based on Antibodies or Aptamers

    PubMed Central

    Xu, Lin; Zhang, Zhaowei; Zhang, Qi; Li, Peiwu

    2016-01-01

    Mycotoxin contamination threatens health and life of humans and animals throughout the food supply chains. Many of the mycotoxins have been proven to be carcinogens, teratogens and mutagens. The reliable and sensitive sensing methods are requested to monitor mycotoxin contamination. Advanced sensors based on antibodies or aptamers boast the advantages of high sensitivity and rapidity, and have been used in the mycotoxin sensing. These sensors are miniaturized, thereby lowering costs, and are applicable to high-throughput modes. In this work, the latest developments in sensing strategies for mycotoxin determination were critically discussed. Optical and electrochemical sensing modes were compared. The sensing methods for single mycotoxin or multiple mycotoxins in food samples were reviewed, along with the challenges and the future of antibody or aptamer-based sensors. This work might promote academic studies and industrial applications for mycotoxin sensing. PMID:27529281

  1. Mycotoxin Determination in Foods Using Advanced Sensors Based on Antibodies or Aptamers.

    PubMed

    Xu, Lin; Zhang, Zhaowei; Zhang, Qi; Li, Peiwu

    2016-01-01

    Mycotoxin contamination threatens health and life of humans and animals throughout the food supply chains. Many of the mycotoxins have been proven to be carcinogens, teratogens and mutagens. The reliable and sensitive sensing methods are requested to monitor mycotoxin contamination. Advanced sensors based on antibodies or aptamers boast the advantages of high sensitivity and rapidity, and have been used in the mycotoxin sensing. These sensors are miniaturized, thereby lowering costs, and are applicable to high-throughput modes. In this work, the latest developments in sensing strategies for mycotoxin determination were critically discussed. Optical and electrochemical sensing modes were compared. The sensing methods for single mycotoxin or multiple mycotoxins in food samples were reviewed, along with the challenges and the future of antibody or aptamer-based sensors. This work might promote academic studies and industrial applications for mycotoxin sensing. PMID:27529281

  2. Orbital Express Advanced Video Guidance Sensor: Ground Testing, Flight Results and Comparisons

    NASA Technical Reports Server (NTRS)

    Pinson, Robin M.; Howard, Richard T.; Heaton, Andrew F.

    2008-01-01

    Orbital Express (OE) was a successful mission demonstrating automated rendezvous and docking. The 2007 mission consisted of two spacecraft, the Autonomous Space Transport Robotic Operations (ASTRO) and the Next Generation Serviceable Satellite (NEXTSat) that were designed to work together and test a variety of service operations in orbit. The Advanced Video Guidance Sensor, AVGS, was included as one of the primary proximity navigation sensors on board the ASTRO. The AVGS was one of four sensors that provided relative position and attitude between the two vehicles. Marshall Space Flight Center was responsible for the AVGS software and testing (especially the extensive ground testing), flight operations support, and analyzing the flight data. This paper briefly describes the historical mission, the data taken on-orbit, the ground testing that occurred, and finally comparisons between flight data and ground test data for two different flight regimes.

  3. Large scale evaluation of soil moisture retrievals from passive microwave observations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For several years passive microwave observations have been used to retrieve surface soil moisture from the Earth’s surface. Several satellite sensors such as the Advanced Microwave Scanning Radiometer-EOS (AMSR-E) and WindSat have been used for this purpose using multi-channel observations. Large sc...

  4. An Advanced Compiler Designed for a VLIW DSP for Sensors-Based Systems

    PubMed Central

    Yang, Xu; He, Hu

    2012-01-01

    The VLIW architecture can be exploited to greatly enhance instruction level parallelism, thus it can provide computation power and energy efficiency advantages, which satisfies the requirements of future sensor-based systems. However, as VLIW codes are mainly compiled statically, the performance of a VLIW processor is dominated by the behavior of its compiler. In this paper, we present an advanced compiler designed for a VLIW DSP named Magnolia, which will be used in sensor-based systems. This compiler is based on the Open64 compiler. We have implemented several advanced optimization techniques in the compiler, and fulfilled the O3 level optimization. Benchmarks from the DSPstone test suite are used to verify the compiler. Results show that the code generated by our compiler can make the performance of Magnolia match that of the current state-of-the-art DSP processors. PMID:22666040

  5. Visual Sensor Technology for Advanced Surveillance Systems: Historical View, Technological Aspects and Research Activities in Italy

    PubMed Central

    Foresti, Gian Luca; Micheloni, Christian; Piciarelli, Claudio; Snidaro, Lauro

    2009-01-01

    The paper is a survey of the main technological aspects of advanced visual-based surveillance systems. A brief historical view of such systems from the origins to nowadays is given together with a short description of the main research projects in Italy on surveillance applications in the last twenty years. The paper then describes the main characteristics of an advanced visual sensor network that (a) directly processes locally acquired digital data, (b) automatically modifies intrinsic (focus, iris) and extrinsic (pan, tilt, zoom) parameters to increase the quality of acquired data and (c) automatically selects the best subset of sensors in order to monitor a given moving object in the observed environment. PMID:22574011

  6. Advanced Sensors and Controls for Building Applications: Market Assessment and Potential R&D Pathways

    SciTech Connect

    Brambley, Michael R.; Haves, Philip; McDonald, Sean C.; Torcellini, Paul; Hansen, David G.; Holmberg, David; Roth, Kurt

    2005-04-13

    Significant energy savings can be achieved in commercial building operation, along with increased comfort and control for occupants, through the implementation of advanced technologies. This document provides a market assessment of existing building sensors and controls and presents a range of technology pathways (R&D options) for pursuing advanced sensors and building control strategies. This paper is actually a synthesis of five other white papers: the first describes the market assessment including estimates of market potential and energy savings for sensors and control strategies currently on the market as well as a discussion of market barriers to these technologies. The other four cover technology pathways: (1) current applications and strategies for new applications, (2) sensors and controls, (3) networking, security, and protocols and standards, and (4) automated diagnostics, performance monitoring, commissioning, optimal control and tools. Each technology pathway chapter gives an overview of the technology or application. This is followed by a discussion of needs and the current status of the technology. Finally, a series of research topics is proposed.

  7. Advanced computational sensors technology: testing and evaluation in visible, SWIR, and LWIR imaging

    NASA Astrophysics Data System (ADS)

    Rizk, Charbel G.; Wilson, John P.; Pouliquen, Philippe

    2015-05-01

    The Advanced Computational Sensors Team at the Johns Hopkins University Applied Physics Laboratory and the Johns Hopkins University Department of Electrical and Computer Engineering has been developing advanced readout integrated circuit (ROIC) technology for more than 10 years with a particular focus on the key challenges of dynamic range, sampling rate, system interface and bandwidth, and detector materials or band dependencies. Because the pixel array offers parallel sampling by default, the team successfully demonstrated that adding smarts in the pixel and the chip can increase performance significantly. Each pixel becomes a smart sensor and can operate independently in collecting, processing, and sharing data. In addition, building on the digital circuit revolution, the effective well size can be increased by orders of magnitude within the same pixel pitch over analog designs. This research has yielded an innovative class of a system-on-chip concept: the Flexible Readout and Integration Sensor (FRIS) architecture. All key parameters are programmable and/or can be adjusted dynamically, and this architecture can potentially be sensor and application agnostic. This paper reports on the testing and evaluation of one prototype that can support either detector polarity and includes sample results with visible, short-wavelength infrared (SWIR), and long-wavelength infrared (LWIR) imaging.

  8. All-Weather Sounding of Moisture and Temperature From Microwave Sensors Using a Coupled Surface/Atmosphere Inversion Algorithm

    NASA Astrophysics Data System (ADS)

    Boukabara, S. A.; Garrett, K.

    2014-12-01

    A one-dimensional variational retrieval system has been developed, capable of producing temperature and water vapor profiles in clear, cloudy and precipitating conditions. The algorithm, known as the Microwave Integrated Retrieval System (MiRS), is currently running operationally at the National Oceanic and Atmospheric Administration (NOAA) National Environmental Satellite Data and Information Service (NESDIS), and is applied to a variety of data from the AMSU-A/MHS sensors on board the NOAA-18, NOAA-19, and MetOp-A/B polar satellite platforms, as well as SSMI/S on board both DMSP F-16 and F18, and from the NPP ATMS sensor. MiRS inverts microwave brightness temperatures into atmospheric temperature and water vapor profiles, along with hydrometeors and surface parameters, simultaneously. This atmosphere/surface coupled inversion allows for more accurate retrievals in the lower tropospheric layers by accounting for the surface emissivity impact on the measurements. It also allows the inversion of the soundings in all-weather conditions thanks to the incorporation of the hydrometeors parameters in the inverted state vector as well as to the inclusion of the emissivity in the same state vector, which is accounted for dynamically for the highly variable surface conditions found under precipitating atmospheres. The inversion is constrained in precipitating conditions by the inclusion of covariances for hydrometeors, to take advantage of the natural correlations that exist between temperature and water vapor with liquid and ice cloud along with rain water. In this study, we present a full assessment of temperature and water vapor retrieval performances in all-weather conditions and over all surface types (ocean, sea-ice, land, and snow) using matchups with radiosonde as well as Numerical Weather Prediction and other satellite retrieval algorithms as references. An emphasis is placed on retrievals in cloudy and precipitating atmospheres, including extreme weather events

  9. Future Soil Moisture Satellite Missions and Research Needs

    NASA Astrophysics Data System (ADS)

    Njoku, E. G.; Jackson, T. J.; O'Neill, P. E.

    2001-12-01

    During the coming decade, launches of a number of satellite microwave sensors will provide new and unique opportunities for acquiring global information on the amount and distribution of surface soil moisture and its frozen/thawed state. This new information will provide potentially significant enhancements to the predictive capabilities of numerical weather and climate models as well as improved capabilities for monitoring and predicting floods, droughts, and other natural hazards. The development focus has been on L-band (1.4 GHz) passive microwave sensors (radiometers) as the basis for new satellite mission concepts since these instruments are uniquely suited to acquiring soil moisture information over a wide range of vegetation and heterogeneous terrain, and under nearly all weather conditions. Active microwave sensors (radars) can provide higher spatial resolution measurements and, in combination with passive sensors, enhanced information on surface moisture and its freeze/thaw condition. The soil moisture and surface freeze/thaw state together control the `surface resistance' to water and energy exchanges at the surface. Among the new soil moisture mission concepts under consideration for launch in ~2005 or later are the Soil Moisture and Ocean Salinity (SMOS) and Hydrosphere States (HYDROS) missions, and higher-resolution follow-on missions. These missions use different but complementary technological approaches to surface soil moisture sensing. In the nearer term, launches of the Advanced Scanning Microwave Radiometers (AMSRs) on the NASA EOS-Aqua and National Space Development Agency of Japan ADEOS-II satellites in 2002, and similar instruments to be launched in subsequent years as part of Department of Defense and National Polar-orbiting Operational Environmental Satellite System (NPOESS) programs, will provide new C-band (~6.9 GHz) data that will be useful for soil moisture monitoring under more limited vegetation and environmental conditions. There are

  10. High-speed limnology: using advanced sensors to investigate spatial variability in biogeochemistry and hydrology.

    PubMed

    Crawford, John T; Loken, Luke C; Casson, Nora J; Smith, Colin; Stone, Amanda G; Winslow, Luke A

    2015-01-01

    Advanced sensor technology is widely used in aquatic monitoring and research. Most applications focus on temporal variability, whereas spatial variability has been challenging to document. We assess the capability of water chemistry sensors embedded in a high-speed water intake system to document spatial variability. This new sensor platform continuously samples surface water at a range of speeds (0 to >45 km h(-1)) resulting in high-density, mesoscale spatial data. These novel observations reveal previously unknown variability in physical, chemical, and biological factors in streams, rivers, and lakes. By combining multiple sensors into one platform, we were able to detect terrestrial-aquatic hydrologic connections in a small dystrophic lake, to infer the role of main-channel vs backwater nutrient processing in a large river and to detect sharp chemical changes across aquatic ecosystem boundaries in a stream/lake complex. Spatial sensor data were verified in our examples by comparing with standard lab-based measurements of selected variables. Spatial fDOM data showed strong correlation with wet chemistry measurements of DOC, and optical NO3 concentrations were highly correlated with lab-based measurements. High-frequency spatial data similar to our examples could be used to further understand aquatic biogeochemical fluxes, ecological patterns, and ecosystem processes, and will both inform and benefit from fixed-site data. PMID:25406073

  11. FY97 report on moisture sensors for enhanced surveillance program project LL-ESP96-13

    SciTech Connect

    Anderson, B.B.; Baylor, L.C.; Sanders, M.A.

    1997-09-23

    Several compounds were evaluated in a number of optical configurations in order to test the optical response of these compounds to changes in humidity. Reichardt`s betaine (Reichardt`s dye, ET-30 dye, 2,6-diphenyl-4-(2,4,6-triphenyl-N-pyridinio)phenolate), a solvatochromic molecule, and several vapochromic compounds were tested, and each responded to a wide range of humidity by exhibiting shifts in visible absorption. All compounds in the study suffered from some degree of hysteresis upon humidity cycling. It is unclear as to the mechanism for this hysteresis, but future work will attempt to either model or remove the hysteresis effects. In the case of the vapochromic compounds, the hysteresis may be due to structural changes in the crystal lattice of the solid state compound. A prototype sensor configuration was also developed involving an attenuated total reflectance probe. The future of the project will deal with elucidating the hysteresis mechanisms for each compound, evaluating several other vapochromic compounds, and testing different immobilization schemes for the compounds under study. In addition, several other optical technologies will be investigated for application in optical humidity sensing.

  12. Comparison of NOAA-CREST Soil Moisture Measurements with SMOS Products

    NASA Astrophysics Data System (ADS)

    Norouzi, H.; Forbes, A.

    2014-12-01

    In October 2014, the Soil Moisture Active and Passive mission (SMAP) will launch into a near-polar and sun- synchronous orbit. SMAP includes the first 3 KM resolution product, by both radar and radiometer sensors which will transmit useful information concentrating on the global measurements of soil moisture and freeze/thaw cycles. NOAA- CREST (National Oceanic and Atmospheric Administration- Cooperative Remote Sensing Science and Technology) deploys a series of in-situ devices into the soil, and an L-BAND Radiometer close to the site ground at the Cary Institute in Millbrook, NY. The site is important for future validation of SMAP mission. Comparing mathematical and ground based remote sensing of soil moisture is beneficial to ensure the accuracy of the measurements. The focus of this research is to analyze and compare soil moisture from ESA- SMOS (Europe Space Agency- Soil Moisture Ocean Salinity) mission and the Cary Institute's soil moisture measurements within the same time period, and location. In the interest of establishing superb authentication; comparing SMOS and ground measurements will justify the accuracy of the newly launch satellite. Discrepancies can be found between field point measurement and relatively large footprint of SMOS, which affects comparison and validation. Several techniques and statistical methods will provide a more meaningful comparison to analyze soil moisture data. The results of this project will help to provide a useful method to compare the NOAA-CREST soil moisture measurements and SMAP measurements. In conclusion, the SMAP advance technology will provide more accurate feedback for modeling numerical weather and climate models. Keywords: Soil Moisture, Precipitation, CREST-SMART, Cary Institute, In-situ, Remote Sensors Accurate Soil Moisture Data, Millbrook, N.Y., CATDS, Hydrology is the branch of science concerning properties of earth's water especially its movement in relation to land. SMOS MIRAS, SMAP, Sensors (Underground)

  13. High Neutron Fluence Survivability Testing of Advanced Fiber Bragg Grating Sensors

    SciTech Connect

    Fielder, Robert S.; Klemer, Daniel; Stinson-Bagby, Kelly L.

    2004-02-04

    The motivation for the reported research was to support NASA space nuclear power initiatives through the development of advanced fiber optic sensors for space-based nuclear power applications. The purpose of the high-neutron fluence testing was to demonstrate the survivability of fiber Bragg grating (FBG) sensors in a fission reactor environment. 520 FBGs were installed in the Ford reactor at the University of Michigan. The reactor was operated for 1012 effective full power hours resulting in a maximum neutron fluence of approximately 5x1019 n/cm2, and a maximum gamma dose of 2x103 MGy gamma. This work is significant in that, to the knowledge of the authors, the exposure levels obtained are approximately 1000 times higher than for any previously published experiment. Four different fiber compositions were evaluated. An 87% survival rate was observed for fiber Bragg gratings located at the fuel centerline. Optical Frequency Domain Reflectometry (OFDR), originally developed at the NASA Langley Research Center, can be used to interrogate several thousand low-reflectivity FBG strain and/or temperature sensors along a single optical fiber. A key advantage of the OFDR sensor technology for space nuclear power is the extremely low mass of the sensor, which consists of only a silica fiber 125{mu}m in diameter. The sensors produced using this technology will fill applications in nuclear power for current reactor plants, emerging Generation-IV reactors, and for space nuclear power. The reported research was conducted by Luna Innovations and was funded through a Small Business Innovative Research (SBIR) contract with the NASA Glenn Research Center.

  14. High Neutron Fluence Survivability Testing of Advanced Fiber Bragg Grating Sensors

    NASA Astrophysics Data System (ADS)

    Fielder, Robert S.; Klemer, Daniel; Stinson-Bagby, Kelly L.

    2004-02-01

    The motivation for the reported research was to support NASA space nuclear power initiatives through the development of advanced fiber optic sensors for space-based nuclear power applications. The purpose of the high-neutron fluence testing was to demonstrate the survivability of fiber Bragg grating (FBG) sensors in a fission reactor environment. 520 FBGs were installed in the Ford reactor at the University of Michigan. The reactor was operated for 1012 effective full power hours resulting in a maximum neutron fluence of approximately 5×1019 n/cm2, and a maximum gamma dose of 2×103 MGy gamma. This work is significant in that, to the knowledge of the authors, the exposure levels obtained are approximately 1000 times higher than for any previously published experiment. Four different fiber compositions were evaluated. An 87% survival rate was observed for fiber Bragg gratings located at the fuel centerline. Optical Frequency Domain Reflectometry (OFDR), originally developed at the NASA Langley Research Center, can be used to interrogate several thousand low-reflectivity FBG strain and/or temperature sensors along a single optical fiber. A key advantage of the OFDR sensor technology for space nuclear power is the extremely low mass of the sensor, which consists of only a silica fiber 125μm in diameter. The sensors produced using this technology will fill applications in nuclear power for current reactor plants, emerging Generation-IV reactors, and for space nuclear power. The reported research was conducted by Luna Innovations and was funded through a Small Business Innovative Research (SBIR) contract with the NASA Glenn Research Center.

  15. Recent advances on distributed filtering for stochastic systems over sensor networks

    NASA Astrophysics Data System (ADS)

    Ding, Derui; Wang, Zidong; Shen, Bo

    2014-05-01

    Sensor networks comprising of tiny, power-constrained nodes with sensing, computation, and wireless communication capabilities are gaining popularity due to their potential application in a wide variety of environments like monitoring of environmental attributes and various military and civilian applications. Considering the limited power and communication resources of the sensor nodes, the strategy of the distributed information processing is widely exploited. Therefore, it would be interesting to examine how the topology, network-induced phenomena, and power constraints influence the distributed filtering performance and to obtain some suitable schemes in order to solve the addressed distributed filter design problem. In this paper, we aim to survey some recent advances on the distributed filtering and distributed state estimation problems over the sensor networks with various performance requirements and/or randomly occurring network-induced phenomena. First, some practical filter structures are addressed in detail. Then, the developments of the distributed Kalman filtering, distributed state estimation based on the stability or mean-square error analysis, and distributed ? filtering are systematically reviewed. In addition, latest results on the distributed filtering or state estimation over sensor networks are discussed in great detail and some challenges are highlighted. Finally, some concluding remarks are given and some possible future research directions are pointed out.

  16. Drought monitoring using downscaled soil moisture through machine learning approaches over North and South Korea

    NASA Astrophysics Data System (ADS)

    Park, S.; Im, J.; Rhee, J.; Park, S.

    2015-12-01

    Soil moisture is one of the most important key variables for drought monitoring. It reflects hydrological and agricultural processes because soil moisture is a function of precipitation and energy flux and crop yield is highly related to soil moisture. Many satellites including Advanced Microwave Scanning Radiometer on the Earth Observing System (AMSR-E), Soil Moisture and Ocean Salinity sensor (SMOS), and Soil Moisture Active Passive (SMAP) provide global scale soil moisture products through microwave sensors. However, as the spatial resolution of soil moisture products is typically tens of kilometers, it is difficult to monitor drought using soil moisture at local or regional scale. In this study, AMSR-E and AMSR2 soil moisture were downscaled up to 1 km spatial resolution using Moderate Resolution Imaging Spectroradiometer (MODIS) data—Evapotranspiration, Land Surface Temperature, Leaf Area Index, Normalized Difference Vegetation Index, Enhanced Vegetation Index and Albedo—through machine learning approaches over Korean peninsula. To monitor drought from 2003 to 2014, each pixel of the downscaled soil moisture was scaled from 0 to 1 (1 is the wettest and 0 is the driest). The soil moisture based drought maps were validated using Standardized Precipitation Index (SPI) and crop yield data. Spatial distribution of drought status was also compared with other drought indices such as Scaled Drought Condition Index (SDCI). Machine learning approaches were performed well (R=0.905) for downscaling. Downscaled soil moisture was validated using in situ Asia flux data. The Root Mean Square Errors (RMSE) improved from 0.172 (25 km AMSR2) to 0.065 (downscaled soil moisture). The correlation coefficients improved from 0.201 (25 km AMSR2) to 0.341 (downscaled soil moisture). The soil moisture based drought maps and SDCI showed similar spatial distribution that caught both extreme drought and no drought. Since the proposed drought monitoring approach based on the downscaled

  17. HIRS-AMTS satellite sounding system test - Theoretical and empirical vertical resolving power. [High resolution Infrared Radiation Sounder - Advanced Moisture and Temperature Sounder

    NASA Technical Reports Server (NTRS)

    Thompson, O. E.

    1982-01-01

    The present investigation is concerned with the vertical resolving power of satellite-borne temperature sounding instruments. Information is presented on the capabilities of the High Resolution Infrared Radiation Sounder (HIRS) and a proposed sounding instrument called the Advanced Moisture and Temperature Sounder (AMTS). Two quite different methods for assessing the vertical resolving power of satellite sounders are discussed. The first is the theoretical method of Conrath (1972) which was patterned after the work of Backus and Gilbert (1968) The Backus-Gilbert-Conrath (BGC) approach includes a formalism for deriving a retrieval algorithm for optimizing the vertical resolving power. However, a retrieval algorithm constructed in the BGC optimal fashion is not necessarily optimal as far as actual temperature retrievals are concerned. Thus, an independent criterion for vertical resolving power is discussed. The criterion is based on actual retrievals of signal structure in the temperature field.

  18. Electrocatalytic interface based on novel carbon nanomaterials for advanced electrochemical sensors

    SciTech Connect

    Zhou, Ming; Guo, Shaojun

    2015-07-17

    The rapid development of nanoscience and nanotechnology provides new opportunities for the sustainable progress of nanoscale catalysts (i.e., nanocatalysts). The introduction of nanocatalysts into electronic devices implants their novel functions into electronic sensing systems, resulting in the testing of many advanced electrochemical sensors and the fabrication of some highly sensitive, selective, and stable sensing platforms. In this Review, we will summarize recent significant progress on exploring advanced carbon nanomaterials (such as carbon nanotubes, graphene, highly ordered mesoporous carbons, and electron cyclotron resonance sputtered nanocarbon film) as nanoscale electrocatalysts (i.e., nanoelectrocatalysts) for constructing the catalytic nanointerfaces of electronic devices to achieve high-sensitivity and high-selectivity electrochemical sensors. Furthermore, different mechanisms for the extraordinary and unique electrocatalytic activities of these carbon nanomaterials will be also highlighted, compared and discussed. An outlook on the future trends and developments in this area will be provided at the end. Notably, to elaborate the nature of carbon nanomaterial, we will mainly focus on the electrocatalysis of single kind of carbon materials rather than their hybrid composite materials. As a result, we expect that advanced carbon nanomaterials with unique electrocatalytic activities will continue to attract increasing research interest and lead to new opportunities in various fields of research.

  19. Electrocatalytic interface based on novel carbon nanomaterials for advanced electrochemical sensors

    DOE PAGESBeta

    Zhou, Ming; Guo, Shaojun

    2015-07-17

    The rapid development of nanoscience and nanotechnology provides new opportunities for the sustainable progress of nanoscale catalysts (i.e., nanocatalysts). The introduction of nanocatalysts into electronic devices implants their novel functions into electronic sensing systems, resulting in the testing of many advanced electrochemical sensors and the fabrication of some highly sensitive, selective, and stable sensing platforms. In this Review, we will summarize recent significant progress on exploring advanced carbon nanomaterials (such as carbon nanotubes, graphene, highly ordered mesoporous carbons, and electron cyclotron resonance sputtered nanocarbon film) as nanoscale electrocatalysts (i.e., nanoelectrocatalysts) for constructing the catalytic nanointerfaces of electronic devices to achievemore » high-sensitivity and high-selectivity electrochemical sensors. Furthermore, different mechanisms for the extraordinary and unique electrocatalytic activities of these carbon nanomaterials will be also highlighted, compared and discussed. An outlook on the future trends and developments in this area will be provided at the end. Notably, to elaborate the nature of carbon nanomaterial, we will mainly focus on the electrocatalysis of single kind of carbon materials rather than their hybrid composite materials. As a result, we expect that advanced carbon nanomaterials with unique electrocatalytic activities will continue to attract increasing research interest and lead to new opportunities in various fields of research.« less

  20. Advances in Remote Sensing for Oil Spill Disaster Management: State-of-the-Art Sensors Technology for Oil Spill Surveillance

    PubMed Central

    Jha, Maya Nand; Levy, Jason; Gao, Yang

    2008-01-01

    Reducing the risk of oil spill disasters is essential for protecting the environment and reducing economic losses. Oil spill surveillance constitutes an important component of oil spill disaster management. Advances in remote sensing technologies can help to identify parties potentially responsible for pollution and to identify minor spills before they cause widespread damage. Due to the large number of sensors currently available for oil spill surveillance, there is a need for a comprehensive overview and comparison of existing sensors. Specifically, this paper examines the characteristics and applications of different sensors. A better understanding of the strengths and weaknesses of oil spill surveillance sensors will improve the operational use of these sensors for oil spill response and contingency planning. Laser fluorosensors were found to be the best available sensor for oil spill detection since they not only detect and classify oil on all surfaces but also operate in either the day or night. For example, the Scanning Laser Environmental Airborne Fluorosensor (SLEAF) sensor was identified to be a valuable tool for oil spill surveillance. However, no single sensor was able to provide all information required for oil spill contingency planning. Hence, combinations of sensors are currently used for oil spill surveillance. Specifically, satellite sensors are used for preliminary oil spill assessment while airborne sensors are used for detailed oil spill analysis. While satellite remote sensing is not suitable for tactical oil spill planning it can provide a synoptic coverage of the affected area.

  1. Development of Advanced Electrochemical Sensors for DNA Detection at the Point of Care

    NASA Astrophysics Data System (ADS)

    Hsieh, Kuangwen

    In the post-genomic era, ever-advancing capabilities in DNA detection and analysis have become vital to the detection of infectious diseases and the diagnosis of genetic abnormalities and inheritable diseases. The benefit of such capabilities, however, has yet to reach patients outside of centralized facilities. There thus exists an increasing need to decentralize DNA detection methods and to administer such diagnostics at the "point of care." Electrochemical-based DNA sensors present a compelling approach, but have yet to deliver satisfactory sensitivity, specificity, miniaturization, and real-time monitoring capability to meet the demand of point-of-care diagnostics. Motivated by their potential and their current limitations, in this dissertation, we present a series of strategies that we have undertaken in order to address the key shortcomings of electrochemical DNA sensors and advance them toward point-of-care applications. First, we report a single-step, single reagent, label-free, isothermal electrochemical DNA sensor based on the phenomenon of enzyme catalyzed target recycling amplification. Using this technique, we achieve improved detection limit in comparison to hybridization-based sensors without amplification. We also demonstrate greater than 16-fold amplification of signal at low target concentrations. Next, we present a novel electrochemical DNA sensor that detects single-nucleotide mismatched targets with unprecedented "polarity-switching" responses. This "bipolar" sensor employs a surface-bound and redox-modified (methylene blue) DNA probe architecture, and outputs a decreased Faradaic current when hybridized to a perfectly matched (PM) target, but conversely reports an increased Faradaic current when hybridized to a single-base mismatched (SM) target. Third, we describe the microfluidic electrochemical dynamic allele specific hybridization (microE-DASH) platform for versatile and rapid detection of single-nucleotide polymorphisms. Implementing

  2. Recent advances in near-surface moisture monitoring using commercial microwave links in Tel-Aviv University

    NASA Astrophysics Data System (ADS)

    Alpert, Pinhas; David, Noam; Messer, Hagit

    2015-04-01

    The propagation of electromagnetic radiation in the lower atmosphere, at centimeter wavelengths, is impaired by atmospheric conditions. Absorption and scattering of the radiation, at frequencies of tens of GHz, are directly related to the atmospheric phenomena, primarily precipitation, oxygen, mist, fog and water vapor. As was recently shown, wireless communication networks supply high resolution precipitation measurements at ground level while often being situated in flood prone areas, covering large parts of these hazardous regions. On the other hand, at present, there are no satisfactory real time flash flood warning facilities found to cope well with this phenomenon. I will exemplify the flash flood warning potential of the commercial wireless communication system for two different semi-arid region cases when floods occurred in the Judean desert and in the northern Negev in Israel. In addition, I will review our recent improvements in monitoring rainfall as well as other-than-rain phenomena like, atmospheric moisture. Special focus on fog monitoring potential will be highlighted. References: N. David, O. Sendik, H. Messer and P. Alpert, "Cellular network infrastructure- the future of fog monitoring?", BAMS, (in press, 2015). N. David, P. Alpert and H. Messer, "The potential of cellular network infrastructures for sudden rainfall monitoring in dry climate regions", Atmospheric Research, 131, 13-21, 2013.

  3. Analyses of the lunar surface with advanced remote sensors: Expectations for the 1990's

    NASA Technical Reports Server (NTRS)

    Pieters, Carle M.

    1991-01-01

    Today's advanced sensor capabilities provide unprecedented opportunities for exploration that mesh well with the science requirements for a sophisticated integration of several types of remotely acquired information. Science priorities for the 1990's include an evaluation of the global composition and structure of the primordial lunar crust in order to model its origin and evolution, using the Moon as a natural laboratory to study the impact process and time-cumulative events at 1 AU, and, ultimately, constraining the origin of the Moon and its relation to Earth.

  4. Underwater acoustic wireless sensor networks: advances and future trends in physical, MAC and routing layers.

    PubMed

    Climent, Salvador; Sanchez, Antonio; Capella, Juan Vicente; Meratnia, Nirvana; Serrano, Juan Jose

    2014-01-01

    This survey aims to provide a comprehensive overview of the current research on underwater wireless sensor networks, focusing on the lower layers of the communication stack, and envisions future trends and challenges. It analyzes the current state-of-the-art on the physical, medium access control and routing layers. It summarizes their security threads and surveys the currently proposed studies. Current envisioned niches for further advances in underwater networks research range from efficient, low-power algorithms and modulations to intelligent, energy-aware routing and medium access control protocols. PMID:24399155

  5. Geospace Science from Ground-based Magnetometer Arrays: Advances in Sensors, Data Collection, and Data Integration

    NASA Astrophysics Data System (ADS)

    Mann, Ian; Chi, Peter

    2016-07-01

    Networks of ground-based magnetometers now provide the basis for the diagnosis of magnetic disturbances associated with solar wind-magnetosphere-ionosphere coupling on a truly global scale. Advances in sensor and digitisation technologies offer increases in sensitivity in fluxgate, induction coil, and new micro-sensor technologies - including the promise of hybrid sensors. Similarly, advances in remote connectivity provide the capacity for truly real-time monitoring of global dynamics at cadences sufficient for monitoring and in many cases resolving system level spatio-temporal ambiguities especially in combination with conjugate satellite measurements. A wide variety of the plasmaphysical processes active in driving geospace dynamics can be monitored based on the response of the electrical current system, including those associated with changes in global convection, magnetospheric substorms and nightside tail flows, as well as due to solar wind changes in both dynamic pressure and in response to rotations of the direction of the IMF. Significantly, any changes to the dynamical system must be communicated by the propagation of long-period Alfven and/or compressional waves. These wave populations hence provide diagnostics for not only the energy transport by the wave fields themselves, but also provide a mechanism for diagnosing the structure of the background plasma medium through which the waves propagate. Ultra-low frequency (ULF) waves are especially significant in offering a monitor for mass density profiles, often invisible to particle detectors because of their very low energy, through the application of a variety of magneto-seismology and cross-phase techniques. Renewed scientific interest in the plasma waves associated with near-Earth substorm dynamics, including magnetosphere-ionosphere coupling at substorm onset and their relation to magnetotail flows, as well the importance of global scale ultra-low frequency waves for the energisation, transport

  6. Advanced detection, isolation, and accommodation of sensor failures in turbofan engines: Real-time microcomputer implementation

    NASA Technical Reports Server (NTRS)

    Delaat, John C.; Merrill, Walter C.

    1990-01-01

    The objective of the Advanced Detection, Isolation, and Accommodation Program is to improve the overall demonstrated reliability of digital electronic control systems for turbine engines. For this purpose, an algorithm was developed which detects, isolates, and accommodates sensor failures by using analytical redundancy. The performance of this algorithm was evaluated on a real time engine simulation and was demonstrated on a full scale F100 turbofan engine. The real time implementation of the algorithm is described. The implementation used state-of-the-art microprocessor hardware and software, including parallel processing and high order language programming.

  7. Underwater Acoustic Wireless Sensor Networks: Advances and Future Trends in Physical, MAC and Routing Layers

    PubMed Central

    Climent, Salvador; Sanchez, Antonio; Capella, Juan Vicente; Meratnia, Nirvana; Serrano, Juan Jose

    2014-01-01

    This survey aims to provide a comprehensive overview of the current research on underwater wireless sensor networks, focusing on the lower layers of the communication stack, and envisions future trends and challenges. It analyzes the current state-of-the-art on the physical, medium access control and routing layers. It summarizes their security threads and surveys the currently proposed studies. Current envisioned niches for further advances in underwater networks research range from efficient, low-power algorithms and modulations to intelligent, energy-aware routing and medium access control protocols. PMID:24399155

  8. A Modified Kriging Method to Interpolate the Soil Moisture Measured by Wireless Sensor Network with the Aid of Remote Sensing Images

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Liu, Q.; Li, X.; Niu, H.; Cai, E.

    2015-12-01

    In recent years, wireless sensor network (WSN) emerges to collect Earth observation data at relatively low cost and light labor load, while its observations are still point-data. To learn the spatial distribution of a land surface parameter, interpolating the point data is necessary. Taking soil moisture (SM) for example, its spatial distribution is critical information for agriculture management, hydrological and ecological researches. This study developed a method to interpolate the WSN-measured SM to acquire the spatial distribution in a 5km*5km study area, located in the middle reaches of HEIHE River, western China. As SM is related to many factors such as topology, soil type, vegetation and etc., even the WSN observation grid is not dense enough to reflect the SM distribution pattern. Our idea is to revise the traditional Kriging algorithm, introducing spectral variables, i.e., vegetation index (VI) and abledo, from satellite imagery as supplementary information to aid the interpolation. Thus, the new Extended-Kriging algorithm operates on the spatial & spectral combined space. To run the algorithm, first we need to estimate the SM variance function, which is also extended to the combined space. As the number of WSN samples in the study area is not enough to gather robust statistics, we have to assume that the SM variance function is invariant over time. So, the variance function is estimated from a SM map, derived from the airborne CASI/TASI images acquired in July 10, 2012, and then applied to interpolate WSN data in that season. Data analysis indicates that the new algorithm can provide more details to the variation of land SM. Then, the Leave-one-out cross-validation is adopted to estimate the interpolation accuracy. Although a reasonable accuracy can be achieved, the result is not yet satisfactory. Besides improving the algorithm, the uncertainties in WSN measurements may also need to be controlled in our further work.

  9. An Overview of Production and Validation of the SMAP Passive Soil Moisture Product

    NASA Technical Reports Server (NTRS)

    Chan, S.; O'Neill, P.; Njoku, E.; Jackson, T.; Bindlish, R.

    2015-01-01

    The Soil Moisture Active Passive (SMAP) mission is an L-band mission scheduled for launch in Jan. 2015. The SMAP instruments consist of a radar and a radiometer to obtain complementary information from space for soil moisture and freeze/thaw state research and applications. By utilizing novel designs in antenna construction, retrieval algorithms, and acquisition hardware, SMAP provides a capability for global mapping of soil moisture and freeze/thaw state with unprecedented accuracy, resolution, and coverage. This improvement in hydrosphere state measurement is expected to advance our understanding of the processes that link the terrestrial water, energy and carbon cycles, improve our capability in flood prediction and drought monitoring, and enhance our skills in weather and climate forecast. For swath-based soil moisture measurement, SMAP generates three operational geophysical data products: (1) the radiometer-only soil moisture product (L2_SM_P) posted at 36-kilometer resolution, (2) the radar-only soil moisture product (L2_SM_A) posted at 3-kilometers resolution, and (3) the radar-radiometer combined soil moisture product (L2_SM_AP) posted at 9-kilometers resolution. Each product draws on the strengths of the underlying sensor(s) and plays a unique role in hydroclimatological and hydrometeorological applications. A full suite of SMAP data products is given in Table 1.

  10. Nondestructive measurement of moisture content of different types of wheat using a single calibration with a parallel-plate capacitance sensor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A simple, low cost instrument that measures impedance and phase angle was used along with a parallel-plate capacitance system to estimate the moisture content (MC) of six types of wheat. Moisture content of grain is important and is measured at various stages of their processing and storage. A sampl...

  11. The Integration of SMOS Soil Moisture in a Consistent Soil Moisture Climate Record

    NASA Astrophysics Data System (ADS)

    de Jeu, Richard; Kerr, Yann; Wigneron, Jean Pierre; Rodriguez-Fernandez, Nemesio; Al-Yaari, Amen; van der Schalie, Robin; Dolman, Han; Drusch, Matthias; Mecklenburg, Susanne

    2015-04-01

    Recently, a study funded by the European Space Agency (ESA) was set up to provide guidelines for the development of a global soil moisture climate record with a special emphasis on the integration of SMOS. Three different data fusion approaches were designed and implemented on 10 year passive microwave data (2003-2013) from two different satellite sensors; the ESA Soil Moisture Ocean Salinity Mission (SMOS) and the NASA/JAXA Advanced Scanning Microwave Radiometer (AMSR-E). The AMSR-E data covered the period from January 2003 until Oct 2011 and SMOS data covered the period from June 2010 until the end of 2013. The fusion approaches included a neural network approach (Rodriguez-Fernandez et al., this conference session HS6.4), a regression approach (Wigneron et al., 2004), and an approach based on the baseline algorithm of ESAs current Climate Change Initiative soil moisture program, the Land Parameter Retrieval Model (Van der Schalie et al., this conference session HS6.4). With this presentation we will show the first results from this study including a description of the different approaches and the validation activities using both globally covered modeled datasets and ground observations from the international soil moisture network. The statistical validation analyses will give us information on the temporal and spatial performance of the three different approaches. Based on these results we will then discuss the next steps towards a seamless integration of SMOS in a consistent soil moisture climate record. References Wigneron J.-P., J.-C. Calvet, P. de Rosnay, Y. Kerr, P. Waldteufel, K. Saleh, M. J. Escorihuela, A. Kruszewski, 'Soil Moisture Retrievals from Bi-Angular L-band Passive Microwave Observations', IEEE Trans. Geosc. Remote Sens. Let., vol 1, no. 4, 277-281, 2004.

  12. Buried explosive hazard characterization using advanced magnetic and electromagnetic induction sensors

    NASA Astrophysics Data System (ADS)

    Miller, Jonathan S.; Schultz, Gregory; Shah, Vishal

    2013-06-01

    Advanced electromagnetic induction arrays that feature high sensitivity wideband magnetic field and electromagnetic induction receivers provide significant capability enhancement to landmine, unexploded ordnance, and buried explosives detection applications. Specifically, arrays that are easily and quickly configured for integration with a variety of ground vehicles and mobile platforms offer improved safety and efficiency to personnel conducting detection operations including route clearance, explosive ordnance disposal, and humanitarian demining missions. We present experimental results for explosives detection sensor concepts that incorporate both magnetic and electromagnetic modalities. Key technology components include a multi-frequency continuous wave EMI transmitter, multi-axis induction coil receivers, and a high sensitivity chip scale atomic magnetometer. The use of multi-frequency transmitters provides excitation of metal encased threats as well as low conductivity non-metallic explosive constituents. The integration of a radio frequency tunable atomic magnetometer receiver adds increased sensitivity to lower frequency components of the electromagnetic response. This added sensitivity provides greater capability for detecting deeply buried targets. We evaluate the requirements for incorporating these sensor modalities in forward mounted ground vehicle operations. Specifically, the ability to detect target features in near real-time is critical to non-overpass modes. We consider the requirements for incorporating these sensor technologies in a system that enables detection of a broad range of explosive threats that include both metallic and non-metallic components.

  13. Advancements of data anomaly detection research in wireless sensor networks: a survey and open issues.

    PubMed

    Rassam, Murad A; Zainal, Anazida; Maarof, Mohd Aizaini

    2013-01-01

    Wireless Sensor Networks (WSNs) are important and necessary platforms for the future as the concept "Internet of Things" has emerged lately. They are used for monitoring, tracking, or controlling of many applications in industry, health care, habitat, and military. However, the quality of data collected by sensor nodes is affected by anomalies that occur due to various reasons, such as node failures, reading errors, unusual events, and malicious attacks. Therefore, anomaly detection is a necessary process to ensure the quality of sensor data before it is utilized for making decisions. In this review, we present the challenges of anomaly detection in WSNs and state the requirements to design efficient and effective anomaly detection models. We then review the latest advancements of data anomaly detection research in WSNs and classify current detection approaches in five main classes based on the detection methods used to design these approaches. Varieties of the state-of-the-art models for each class are covered and their limitations are highlighted to provide ideas for potential future works. Furthermore, the reviewed approaches are compared and evaluated based on how well they meet the stated requirements. Finally, the general limitations of current approaches are mentioned and further research opportunities are suggested and discussed. PMID:23966182

  14. Advancements of Data Anomaly Detection Research in Wireless Sensor Networks: A Survey and Open Issues

    PubMed Central

    Rassam, Murad A.; Zainal, Anazida; Maarof, Mohd Aizaini

    2013-01-01

    Wireless Sensor Networks (WSNs) are important and necessary platforms for the future as the concept “Internet of Things” has emerged lately. They are used for monitoring, tracking, or controlling of many applications in industry, health care, habitat, and military. However, the quality of data collected by sensor nodes is affected by anomalies that occur due to various reasons, such as node failures, reading errors, unusual events, and malicious attacks. Therefore, anomaly detection is a necessary process to ensure the quality of sensor data before it is utilized for making decisions. In this review, we present the challenges of anomaly detection in WSNs and state the requirements to design efficient and effective anomaly detection models. We then review the latest advancements of data anomaly detection research in WSNs and classify current detection approaches in five main classes based on the detection methods used to design these approaches. Varieties of the state-of-the-art models for each class are covered and their limitations are highlighted to provide ideas for potential future works. Furthermore, the reviewed approaches are compared and evaluated based on how well they meet the stated requirements. Finally, the general limitations of current approaches are mentioned and further research opportunities are suggested and discussed. PMID:23966182

  15. Advancement and results in hostile fire indication using potassium line missile warning sensors

    NASA Astrophysics Data System (ADS)

    Montgomery, Joel; Montgomery, Marjorie; Hardie, Russell

    2014-06-01

    M&M Aviation has been developing and conducting Hostile Fire Indication (HFI) tests using potassium line emission sensors for the Air Force Visible Missile Warning System (VMWS) to advance both algorithm and sensor technologies for UAV and other airborne systems for self protection and intelligence purposes. Work began in 2008 as an outgrowth of detecting and classifying false alarm sources for the VMWS using the same K-line spectral discrimination region but soon became a focus of research due to the high interest in both machine-gun fire and sniper geo-location via airborne systems. Several initial tests were accomplished in 2009 using small and medium caliber weapons including rifles. Based on these results, the Air Force Research Laboratory (AFRL) funded the Falcon Sentinel program in 2010 to provide for additional development of both the sensor concept, algorithm suite changes and verification of basic phenomenology including variance based on ammunition type for given weapons platform. Results from testing over the past 3 years have showed that the system would be able to detect and declare a sniper rifle at upwards of 3km, medium machine gun at 5km, and explosive events like hand-grenades at greater than 5km. This paper will outline the development of the sensor systems, algorithms used for detection and classification, and test results from VMWS prototypes as well as outline algorithms used for the VMWS. The Falcon Sentinel Program will be outlined and results shown. Finally, the paper will show the future work for ATD and transition efforts after the Falcon Sentinel program completed.

  16. Advanced THz sensor array for precise position and material properties recognition

    NASA Astrophysics Data System (ADS)

    Sešek, Aleksander; Trontelj, Janez; Å vigelj, Andrej

    2014-06-01

    The precise position of objects in the industrial process, assembly lines, conveyers, or processing bins is essential for fast and high quality production. In many robotized setups the material type and its properties are crucial. When several types of materials or parts are used, material recognition is required. Advanced robotics systems depend on various sensors to recognize material properties, and high resolution cameras with expensive laser measuring systems are used to determine the precise object position. The purpose of this paper is to present how the THz sensor and THz waves can be applicable for such precise object position sensing and its material properties in real time. One of the additional features of such a THz sensor array is also the ability to see behind barriers that are transparent for THz waves. This allows the system to obtain precise dimensions, position, and material properties of the object, which are invisible for visible light or anyhow obscured to other vision systems. Furthermore, a 3D THz image of the object can also be obtained and, in cases when a visual picture is available, its fusion with a THz image is possible. In the paper a THz sensor array, operating at a 300GHz central frequency and at room conditions is presented, together with the proposed vision system description. The target is illuminated with a frequency modulated, solid state THz source, and provides output power around 1mW. By mixing of the illuminating and reflected signals, the resulting difference frequency signal is obtained. Its amplitude and phase carry all relevant information of the target. Some measurement results are also shown and discussed.

  17. Advanced staring Si PIN visible sensor chip assembly for Bepi-Colombo mission to Mercury

    NASA Astrophysics Data System (ADS)

    Mills, R. E.; Drab, J. J.; Gin, A.

    2009-08-01

    The planet Mercury, by its near proximity to the sun, has always posed a formidable challenge to spacecraft. The Bepi-Colombo mission, coordinated by the European Space Agency, will be a pioneering effort in the investigation of this planet. Raytheon Vision Systems (RVS) has been given the opportunity to develop the radiation hardened, high operability, high SNR, advanced staring focal plane array (FPA) for the spacecraft destined (Fig. 1) to explore the planet Mercury. This mission will launch in 2013 on a journey lasting approximately 6 years. When it arrives at Mercury in August 2019, it will endure temperatures as high as 350°C as well as relatively high radiation environments during its 1 year data collection period from September 2019 until September 2020. To support this challenging goal, RVS has designed and produced a custom visible sensor based on a 2048 x 2048 (2k2) format with a 10 μm unit cell. This sensor will support both the High Resolution Imaging Camera (HRIC) and the Stereo Camera (STC) instruments. This dual purpose sensor was designed to achieve high sensitivity as well as low input noise (<100 e-) for space-based, low light conditions. It also must maintain performance parameters in a total ionizing dose environment up to 70 kRad (Si) as well as immunity to latch-up and singe event upset. This paper will show full sensor chip assembly data highlighting the performance parameters prior to irradiation. Radiation testing performance will be reported by an independent source in a subsequent paper.

  18. GHAPS: A new Green House And Pollutant Sensor

    NASA Astrophysics Data System (ADS)

    Gordley, L. L.; Marshall, B.

    2013-12-01

    Advances in detector arrays, communication technology, global positioning and gas correlation sensors are combined to produce a small, simple, accurate, autonomous gas column sensor with unlimited lifetime. We describe a solar powered, miniature gas correlation sensor that can be placed anywhere that provides unobscured observation of the sun. The sensor will provide column measurements of CH4, CO2 and CO throughout the day, along with estimates of moisture and overcast. This flashlight size device could supply a low cost solution to monitoring the atmospheric abundance of key greenhouse and pollutant gases, including fluxes of gas emanating from areas surrounded by these sensors. The design, implementation strategy and performance estimates are described.

  19. Acquisition and processing of advanced sensor data for ERW and UXO detection and classification

    NASA Astrophysics Data System (ADS)

    Schultz, Gregory M.; Keranen, Joe; Miller, Jonathan S.; Shubitidze, Fridon

    2014-06-01

    The remediation of explosive remnants of war (ERW) and associated unexploded ordnance (UXO) has seen improvements through the injection of modern technological advances and streamlined standard operating procedures. However, reliable and cost-effective detection and geophysical mapping of sites contaminated with UXO such as cluster munitions, abandoned ordnance, and improvised explosive devices rely on the ability to discriminate hazardous items from metallic clutter. In addition to anthropogenic clutter, handheld and vehicle-based metal detector systems are plagued by natural geologic and environmental noise in many post conflict areas. We present new and advanced electromagnetic induction (EMI) technologies including man-portable and towed EMI arrays and associated data processing software. While these systems feature vastly different form factors and transmit-receive configurations, they all exhibit several fundamental traits that enable successful classification of EMI anomalies. Specifically, multidirectional sampling of scattered magnetic fields from targets and corresponding high volume of unique data provide rich information for extracting useful classification features for clutter rejection analysis. The quality of classification features depends largely on the extent to which the data resolve unique physics-based parameters. To date, most of the advanced sensors enable high quality inversion by producing data that are extremely rich in spatial content through multi-angle illumination and multi-point reception.

  20. The Chimera II Real-Time Operating System for advanced sensor-based control applications

    NASA Technical Reports Server (NTRS)

    Stewart, David B.; Schmitz, Donald E.; Khosla, Pradeep K.

    1992-01-01

    Attention is given to the Chimera II Real-Time Operating System, which has been developed for advanced sensor-based control applications. The Chimera II provides a high-performance real-time kernel and a variety of IPC features. The hardware platform required to run Chimera II consists of commercially available hardware, and allows custom hardware to be easily integrated. The design allows it to be used with almost any type of VMEbus-based processors and devices. It allows radially differing hardware to be programmed using a common system, thus providing a first and necessary step towards the standardization of reconfigurable systems that results in a reduction of development time and cost.

  1. Analysis of distributed thermopiezoelectric sensors and actuators in advanced intelligent structures

    NASA Astrophysics Data System (ADS)

    Rao, S. S.; Sunar, M.

    1993-07-01

    The quasistatic equations of piezoelectricity and thermopiezoelectricity are used to develop a finite element formulation of distributed piezoelectric and thermopiezoelectric media. The formulation is then integrated with the distributed sensing and control of advanced intelligent structure design. The procedure is illustrated with the help of two example problems. The purpose of the first example, which consists of two piezoelectric layers used as a bimorph robotic finger, is to check the accuracy of the finite element solution with the analytical one. As a second example, an aluminum beam is utilized along with two polyvinylidene fluoride layers acting as distributed actuator and sensor to study the distributed control of the beam when thermal effects are present. It is concluded that the thermal effects are important in the precision distributed control of intelligent structures.

  2. Advancements in Transmitters and Sensors for Biological Tissue Imaging in Magnetic Induction Tomography

    PubMed Central

    Zakaria, Zulkarnay; Rahim, Ruzairi Abdul; Mansor, Muhammad Saiful Badri; Yaacob, Sazali; Ayub, Nor Muzakkir Nor; Muji, Siti Zarina Mohd.; Rahiman, Mohd Hafiz Fazalul; Aman, Syed Mustafa Kamal Syed

    2012-01-01

    Magnetic Induction Tomography (MIT), which is also known as Electromagnetic Tomography (EMT) or Mutual Inductance Tomography, is among the imaging modalities of interest to many researchers around the world. This noninvasive modality applies an electromagnetic field and is sensitive to all three passive electromagnetic properties of a material that are conductivity, permittivity and permeability. MIT is categorized under the passive imaging family with an electrodeless technique through the use of excitation coils to induce an electromagnetic field in the material, which is then measured at the receiving side by sensors. The aim of this review is to discuss the challenges of the MIT technique and summarize the recent advancements in the transmitters and sensors, with a focus on applications in biological tissue imaging. It is hoped that this review will provide some valuable information on the MIT for those who have interest in this modality. The need of this knowledge may speed up the process of adopted of MIT as a medical imaging technology. PMID:22969341

  3. Design and Performance Evaluation of Sensors and Actuators for Advanced Optical Systems

    NASA Technical Reports Server (NTRS)

    Clark, Natalie

    2011-01-01

    Current state-of-the-art commercial sensors and actuators do not meet many of NASA s next generation spacecraft and instrument needs. Nor do they satisfy the DoD needs for satellite missions, especially micro/nano satellite missions. In an effort to develop advanced optical devices and instruments that meet mission requirements, NASA Langley recently completed construction of a new cleanroom housing equipment capable of fabricating high performance active optic and adaptive optic technologies including deformable mirrors, reconfigurable lenses (both refractive and diffractive), spectrometers, spectro-polarimeters, tunable filters and many other active optic devices. In addition to performance, these advanced optic technologies offer advantages in speed, size, weight, power consumption, and radiation tolerance. The active optic devices described in this paper rely on birefringent liquid crystal materials to alter either the phase or the polarization of the incoming light. Design considerations and performance evaluation results for various NASA applications are presented. Applications presented will include large space telescopes, optical communications, spacecraft windows, coronagraphs, and star trackers. Keywords: Photonics, Adaptive Optics, Tunable Filters, MEMs., MOEMs, Coronagraph, Star Tracker

  4. Advanced Taste Sensors Based on Artificial Lipids with Global Selectivity to Basic Taste Qualities and High Correlation to Sensory Scores

    PubMed Central

    Kobayashi, Yoshikazu; Habara, Masaaki; Ikezazki, Hidekazu; Chen, Ronggang; Naito, Yoshinobu; Toko, Kiyoshi

    2010-01-01

    Effective R&D and strict quality control of a broad range of foods, beverages, and pharmaceutical products require objective taste evaluation. Advanced taste sensors using artificial-lipid membranes have been developed based on concepts of global selectivity and high correlation with human sensory score. These sensors respond similarly to similar basic tastes, which they quantify with high correlations to sensory score. Using these unique properties, these sensors can quantify the basic tastes of saltiness, sourness, bitterness, umami, astringency and richness without multivariate analysis or artificial neural networks. This review describes all aspects of these taste sensors based on artificial lipid, ranging from the response principle and optimal design methods to applications in the food, beverage, and pharmaceutical markets. PMID:22319306

  5. Estimating Root Mean Square Errors in Remotely Sensed Soil Moisture over Continental Scale Domains

    NASA Technical Reports Server (NTRS)

    Draper, Clara S.; Reichle, Rolf; de Jeu, Richard; Naeimi, Vahid; Parinussa, Robert; Wagner, Wolfgang

    2013-01-01

    Root Mean Square Errors (RMSE) in the soil moisture anomaly time series obtained from the Advanced Scatterometer (ASCAT) and the Advanced Microwave Scanning Radiometer (AMSR-E; using the Land Parameter Retrieval Model) are estimated over a continental scale domain centered on North America, using two methods: triple colocation (RMSETC ) and error propagation through the soil moisture retrieval models (RMSEEP ). In the absence of an established consensus for the climatology of soil moisture over large domains, presenting a RMSE in soil moisture units requires that it be specified relative to a selected reference data set. To avoid the complications that arise from the use of a reference, the RMSE is presented as a fraction of the time series standard deviation (fRMSE). For both sensors, the fRMSETC and fRMSEEP show similar spatial patterns of relatively highlow errors, and the mean fRMSE for each land cover class is consistent with expectations. Triple colocation is also shown to be surprisingly robust to representativity differences between the soil moisture data sets used, and it is believed to accurately estimate the fRMSE in the remotely sensed soil moisture anomaly time series. Comparing the ASCAT and AMSR-E fRMSETC shows that both data sets have very similar accuracy across a range of land cover classes, although the AMSR-E accuracy is more directly related to vegetation cover. In general, both data sets have good skill up to moderate vegetation conditions.

  6. Complex land surface phenologies of moisture status

    NASA Astrophysics Data System (ADS)

    Henebry, G. M.; Doubkova, M.

    2006-12-01

    Making cross-scale linkages from experimental plots or flux tower footprints to regional and continental extents is made difficult by disparate spatial and temporal scales between process and observation. While exchanges between the vegetated land surface and the atmospheric boundary layer are continual, sampling and observations are typically intermittent in time and limited across space. Remote sensing of reflected sunlight has proven useful to track ecological dynamics. These observations are, however, restricted to daytime and often obscured by cloud cover, necessitating production of multi-date composites. The current generation of passive microwave radiometers can observe the land surface both day and night regardless of cloudiness, albeit at a spatial resolution coarser than typically used in ecological remote sensing. Datastreams from the AMSR-E (Advanced Microwave Scanning Radiometer-EOS) onboard NASA's Aqua platform are processed daily at the National Snow and Ice Data Center (NSIDC) into various products, including global retrievals of surficial soil moisture and vegetation water content based on microwave brightness temperatures observed at multiple frequencies. Due to sensor orbit and swath width, gaps occur at the lower latitudes in daily products. We have further processed the product-streams from the descending (01:30) and ascending (13:30) orbits into separate smoothed daily composites using an 8-day retrospective moving average. Of particular interest for synoptic ecology is the diel difference in vegetation water content. When the difference between the pre-dawn and the early afternoon values is positive, it suggests that the supply of moisture from the root zone is not able to keep pace with evapotranspiration during the day, but the soil and canopy moisture equalize overnight. Time series of the diel difference show rapid changes in moisture status in response to precipitation events and dry spells. What constitutes the appropriate baseline

  7. Recent Developments in Active and Passive Distributed Temperature Sensing for Soil Moisture Monitoring

    NASA Astrophysics Data System (ADS)

    Steele-Dunne, S. C.; Dong, J.; Hoes, O.; Van De Giesen, N.; Sayde, C.; Ochsner, T. E.; Selker, J. S.

    2015-12-01

    In this presentation we will review recent developments in both active and passive Distributed Temperature Sensing (DTS) for soil moisture monitoring. DTS involves using fiber-optic cables to measure temperature at sub-meter resolution along cables up to several kilometers in length. Soil thermal properties depend on soil moisture. Hence, temperature variations either in response to externally-applied heating (active) or the response to net radiation (passive) can be monitored and used to infer soil moisture. DTS occupies a unique measurement niche, potentially providing soil moisture information at sub-meter resolution over extents on the order of km at sub-daily time steps. It complements observations from point sensors to other innovative measurement techniques like cosmic ray neutron detection methods and GPS reflectometry. DTS is being developed as a tool for the validation of soil moisture observations from remote sensing and for hydrological field investigations. Here, we will discuss both technological and theoretical advances in active and passive DTS for soil moisture monitoring. We will present data from new installations in the Netherlands and the USA to illustrate recent developments. In particular, we will focus on the value of combining temperature observations from DTS with physical models using data assimilation. In addition to yielding improved soil moisture and temperature profile estimates, recent research has shown the potential to also derive information on the soil thermal and hydraulic properties. We will conclude by outlining the current challenges, with particular emphasis on combining active and passive DTS.

  8. An Automated Approach to Peanut dring with real-time monitoring of in-shell Kernel Moisture Content with a Microwave Sensor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Today’s peanut drying processes utilize decision support software based on modeling and require substantial human interaction for moisture sampling. These conditions increase the likelihood of peanuts being overdried or underdried. This research addresses the need for an automated controller with re...

  9. Comparing and Combining Surface Soil Moisture Products from AMSR2

    NASA Astrophysics Data System (ADS)

    Parinussa, R.; Kim, S.; Liu, Y.; Johnson, F.; Sharma, A.

    2015-12-01

    Soil moisture is an important variable in hydrological systems as its part of the water cycle in the atmosphere, the land surface and subsurface. Microwave remote sensing is a viable tool to monitor global soil moisture conditions at regular time intervals. The Advanced Microwave Scanning Radiometer 2 (AMSR2) is a sensor onboard the Global Change Observation Mission 1 - Water that was launched in May 2012. Multiple soil moisture products from AMSR2 observations exist; these were compared and combined with special emphasis to the global scale. The first product is retrieved by the Japan Aerospace Exploration Agency (JAXA) algorithm, the other uses the Land Parameter Retrieval Model (LPRM). These two products were compared against each other and evaluated against COSMOS data over the United States, Australia, Europe and Africa. The temporal correlations highlight differences in the representation of the seasonal cycle of soil moisture. It is hypothesized that four factors, physical surface temperatures, surface roughness, vegetation and ground soil wetness conditions, affect the quality of soil moisture retrievals. The complementary between the products led to the opportunity to combine them into a superior one that benefits from the strengths of both algorithms.These soil moisture algorithms share the same background in the radiative transfer model, but each algorithm applies different approaches to reflect various external conditions. As a result, the performance of the products is complementary in many locations in terms of bias, RMSE and, most importantly temporal correlation coefficients. Here, we present a methodology that combines the two AMSR2 based soil moisture products into a single product, which improves the overall performance by leveraging the strengths of the individual products. The new product is combined by applying an optimal weighting factor, calculated based on variance and correlation coefficients against a reference dataset. The complementary

  10. Final Technical Report - Advanced Optical Sensors to Minimize Energy Consumption in Polymer Extrusion Processes

    SciTech Connect

    Susan J. Foulk

    2012-07-24

    Project Objective: The objectives of this study are to develop an accurate and stable on-line sensor system to monitor color and composition on-line in polymer melts, to develop a scheme for using the output to control extruders to eliminate the energy, material and operational costs of off-specification product, and to combine or eliminate some extrusion processes. Background: Polymer extrusion processes are difficult to control because the quality achieved in the final product is complexly affected by the properties of the extruder screw, speed of extrusion, temperature, polymer composition, strength and dispersion properties of additives, and feeder system properties. Extruder systems are engineered to be highly reproducible so that when the correct settings to produce a particular product are found, that product can be reliably produced time after time. However market conditions often require changes in the final product, different products or grades may be processed in the same equipment, and feed materials vary from lot to lot. All of these changes require empirical adjustment of extruder settings to produce a product meeting specifications. Optical sensor systems that can continuously monitor the composition and color of the extruded polymer could detect process upsets, drift, blending oscillations, and changes in dispersion of additives. Development of an effective control algorithm using the output of the monitor would enable rapid corrections for changes in materials and operating conditions, thereby eliminating most of the scrap and recycle of current processing. This information could be used to identify extruder systems issues, diagnose problem sources, and suggest corrective actions in real-time to help keep extruder system settings within the optimum control region. Using these advanced optical sensor systems would give extruder operators real-time feedback from their process. They could reduce the amount of off-spec product produced and

  11. Role of satellite-derived surface soil moisture retrievals for determining eco-hydrological feedback (Invited)

    NASA Astrophysics Data System (ADS)

    Crow, W. T.; Qiu, J.; Bolten, J. D.

    2013-12-01

    Satellite-derived surface soil moisture products are entering a new era in terms of their availability, time/space coverage and retrieval accuracy. However, the value of these products for diagnosing (and/or quantifying) land-atmosphere-vegetation feedbacks involving soil moisture is still largely undermined. Arguably the most direct of these feedbacks in the coupling between vegetation health/biomass and soil moisture availability within water-limited ecosystems. In data poor areas of the world, remotely-sensed surface soil moisture retrievals can potentially contribute to the study of soil moisture vegetation feedback by filtering errors in model-based predictions of root-zone derived from forcing a soil water balance with uncertain precipitation forcing. In this presentation, we will evaluate this potential by examining the cross-correlation between remotely-sensed vegetation index anomalies and root-zone soil moisture anomalies derived from a global soil water balance model both before and after the assimilation of a satellite-based surface soil moisture retrieval product. An increase in soil moisture/vegetation anomaly cross-correlation can be interpreted as evidence that the assimilation step is enhancing our ability to characterize root-zone soil moisture and the subsequent feedback of root-zone soil moisture anomalies of vegetation health and productivity. Using a retrospective soil moisture product derived from the Advanced Microwave Scanning Radiometer-EOS sensor between July 2002 and October 2011, results clearly demonstrate the value satellite-derived soil moisture for characterizing the coupling between (current) soil moisture and (near-future) vegetation anomalies. A key aspect of this result is overcoming the difference between the vertical support of satellite-derived soil moisture retrievals (typically assumed to be on the order of 1-5 cm) and the vertical root-zone depth of vegetation (typically assumed to be at least 40 cm). Specific strategies

  12. Full-scale engine demonstration of an advanced sensor failure detection, isolation and accommodation algorithm: Preliminary results

    NASA Technical Reports Server (NTRS)

    Merrill, Walter C.; Delaat, John C.; Kroszkewicz, Steven M.; Abdelwahab, Mahmood

    1987-01-01

    The objective of the advanced detection, isolation, and accommodation (ADIA) program is to improve the overall demonstrated reliability of digital electronic control systems for turbine engines. For this purpose, algorithms were developed which detect, isolate, and accommodate sensor failures using analytical redundancy. Preliminary results of a full scale engine demonstration of the ADIA algorithm are presented. Minimum detectable levels of sensor failures for an F100 turbofan engine control system are determined and compared to those obtained during a previous evaluation of this algorithm using a real-time hybrid computer simulation of the engine.

  13. Full-scale engine demonstration of an advanced sensor failure detection, isolation and accommodation algorithm: Preliminary results

    NASA Astrophysics Data System (ADS)

    Merrill, Walter C.; Delaat, John C.; Kroszkewicz, Steven M.; Abdelwahab, Mahmood

    The objective of the advanced detection, isolation, and accommodation (ADIA) program is to improve the overall demonstrated reliability of digital electronic control systems for turbine engines. For this purpose, algorithms were developed which detect, isolate, and accommodate sensor failures using analytical redundancy. Preliminary results of a full scale engine demonstration of the ADIA algorithm are presented. Minimum detectable levels of sensor failures for an F100 turbofan engine control system are determined and compared to those obtained during a previous evaluation of this algorithm using a real-time hybrid computer simulation of the engine.

  14. Full-scale engine demonstration of an advanced sensor failure detection isolation, and accommodation algorithm - Preliminary results

    NASA Technical Reports Server (NTRS)

    Merrill, Walter C.; Delaat, John C.; Kroszkewicz, Steven M.; Abdelwahab, Mahmood

    1987-01-01

    The objective of the advanced detection, isolation, and accommodation (ADIA) program is to improve the overall demonstrated reliability of digital electronic control systems for turbine engines. For this purpose, algorithms were developed which detect, isolate, and accommodate sensor failures using analytical redundancy. Preliminary results of a full scale engine demonstration of the ADIA algorithm are presented. Minimum detectable levels of sensor failures for an F100 turbofan engine control system are determined and compared to those obtained during a previous evaluation of this algorithm using a real-time hybrid computer simulation of the engine.

  15. De-noising of microwave satellite soil moisture time series

    NASA Astrophysics Data System (ADS)

    Su, Chun-Hsu; Ryu, Dongryeol; Western, Andrew; Wagner, Wolfgang

    2013-04-01

    The use of satellite soil moisture data for scientific and operational hydrologic, meteorological and climatological applications is advancing rapidly due to increasing capability and temporal coverage of current and future missions. However evaluation studies of various existing remotely-sensed soil moisture products from these space-borne microwave sensors, which include AMSR-E (Advanced Microwave Scanning Radiometer) on Aqua satellite, SMOS (Soil Moisture and Ocean Salinity) mission and ASCAT (Advanced Scatterometer) on MetOp-A satellite, found them to be significantly different from in-situ observations, showing large biases and different dynamic ranges and temporal patterns (e.g., Albergel et al., 2012; Su et al., 2012). Moreover they can have different error profiles in terms of bias, variance and correlations and their performance varies with land surface characteristics (Su et al., 2012). These severely impede the effort to use soil moisture retrievals from multiple sensors concurrently in land surface modelling, cross-validation and multi-satellite blending. The issue of systematic errors present in data sets should be addressed prior to renormalisation of the data for blending and data assimilation. Triple collocation estimation technique has successfully yielded realistic error estimates (Scipal et al., 2008), but this method relies on availability of large number of coincident data from multiple independent satellite data sets. In this work, we propose, i) a conceptual framework for distinguishing systematic periodic errors in the form of false spectral resonances from non-systematic errors (stochastic noise) in remotely-sensed soil moisture data in the frequency domain; and ii) the use of digital filters to reduce the variance- and correlation-related errors in satellite data. In this work, we focus on the VUA-NASA (Vrije Universiteit Amsterdam with NASA) AMSR-E, CATDS (Centre National d'Etudes Spatiales, CNES) SMOS and TUWIEN (Vienna University of

  16. Advanced unattended sensors and systems: state of the art and future challenges

    NASA Astrophysics Data System (ADS)

    McQuiddy, John H.

    2010-04-01

    The unattended ground sensors (UGS) have come a long way over the more than 40 years they have been used to detect adversarial activities. From large, single phenomenology sensors with little signal processing and point to point communications the technology has now changed to small, intelligent sensors using network communications. This technology change has resulted in far more capable sensors but challenges remain for UGS to be effective in providing information to users.

  17. Sensors 2000! Program: Advanced Biosensor and Measurement Systems Technologies for Spaceflight Research and Concurrent, Earth-Based Applications

    NASA Technical Reports Server (NTRS)

    Hines, J.

    1999-01-01

    Sensors 2000! (S2K!) is a specialized, integrated projects team organized to provide focused, directed, advanced biosensor and bioinstrumentation systems technology support to NASA's spaceflight and ground-based research and development programs. Specific technology thrusts include telemetry-based sensor systems, chemical/ biological sensors, medical and physiological sensors, miniaturized instrumentation architectures, and data and signal processing systems. A concurrent objective is to promote the mutual use, application, and transition of developed technology by collaborating in academic-commercial-govemment leveraging, joint research, technology utilization and commercialization, and strategic partnering alliances. Sensors 2000! is organized around three primary program elements: Technology and Product Development, Technology infusion and Applications, and Collaborative Activities. Technology and Product Development involves development and demonstration of biosensor and biotelemetry systems for application to NASA Space Life Sciences Programs; production of fully certified spaceflight hardware and payload elements; and sensor/measurement systems development for NASA research and development activities. Technology Infusion and Applications provides technology and program agent support to identify available and applicable technologies from multiple sources for insertion into NASA's strategic enterprises and initiatives. Collaborative Activities involve leveraging of NASA technologies with those of other government agencies, academia, and industry to concurrently provide technology solutions and products of mutual benefit to participating members.

  18. SMOS validation of soil moisture and ocen salinity (SMOS) soil moisture over watershed networks in the U.S.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Estimation of soil moisture at large scale has been performed using several satellite-based passive microwave sensors and a variety of retrieval methods. The most recent source of soil moisture is the European Space Agency Soil Moisture and Ocean Salinity (SMOS) mission. A thorough validation must b...

  19. 77 FR 39561 - Advanced Braking Technologies That Rely on Forward-Looking Sensors; Request for Comments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-03

    ... Sensors; Request for Comments AGENCY: National Highway Traffic Safety Administration (NHTSA), Department... technologies that rely on forward-looking sensors to supplement driver braking or to actuate automatic braking... information from forward-looking sensors, usually a camera or radar, to determine whether or not a crash...

  20. Preparation of novel HTS films and tunnel junctions for advanced C3I sensor applications

    NASA Astrophysics Data System (ADS)

    Taylor, Benjamin J.; Emery, Teresa H.; Berggren, Susan A. E.; Leese de Escobar, Anna M.; Jeon, Inho; Maple, M. B.

    2015-05-01

    Research into the development of advanced RF electronics and devices having high-Temperature Superconducting (HTS) circuitry is being carried out in the Cryogenic Exploitation of RF (CERF) laboratory at SPAWAR Systems Center (SSC) - Pacific. Recently, we have developed a novel annealing process wherein a film of YBa2Cu3Ox is produced having a gradient of oxygen composition along a given direction which we refer to as YBa2Cu3O∇x. Such samples are intended for rapid experimental investigation of the evolution of electronic properties within the compound and in combination with structurally compatible functional oxide materials as integrated sensor devices. We present here an investigation as to the extent to which local oxygen content affects the ion milling process in the formation of Josephson junctions in the HTS compound YBa2Cu3O∇x. We find an abrupt transition in the profile and depth of ion milled trenches at oxygen concentrations at and below the well ordered oxygen level, O6.72. The method described here shows good potential for use in the fabrication of large numbers of uniform Josephson junctions in films of YBa2Cu3Ox, as either a complementary processing tool for grain boundary, step edge, or ion damaged formed JJs, or as a stand alone method for producing nano-bridge JJ's.

  1. In-situ sensor monitoring of resin film infusion of advanced fiber architecture preforms

    SciTech Connect

    Kranbuehl, D.E.; Hood, D.; Rogozinski, J.

    1995-12-01

    Resin transfer molding (RTM) of advanced fiber architecture stitched preforms is being developed as a smart cost-effective manufacturing technique for fabricating damage tolerant composite structures with geometrically complex reinforcements. Dry textile preforms are infiltrated with resin and cured in a single step process, thus eliminating separate prepreg manufacture and ply-by-ply lay-up. The number of parameters that must be controlled during infiltration and cure make trial-and-error methods of process cycle optimization extremely inefficient. In situ cure monitoring sensors and an analytical processing model are a superior alternative for the determination of optimum processing cycles, quality assurance, and automated process control. Resin transfer molding experiments have been conducted in a manufacturing plant with a reactive epoxy resin and carbon fabric preforms. Frequency dependent electromagnetic sensing (FDEMS) was used to monitor in situ resin position, viscosity and degree of cure in situ in the mold during the Resin Transfer Molding infiltration and cure process. A science based multi-dimensional model of Resin Transfer Molding (RTM) was used to predict the infiltration behavior, as well as viscosity and degree of cure as the resin flows and cures in the dry textile preform.

  2. Evaluation drought response of tropical dry forests using advanced wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Sanchez-Azofeifa, G. A.

    2015-12-01

    Understanding of the effects of persistent drought in tropical dry forests has not been fully studied until today. In this presentation we will discuss one of the first results on the response of tropical dry forests to drought using advanced wireless sensor networks and canopy phenology towers, that provide hyper-temporal information on micro-meteorological variables such Temperature, relative humidity, and Vapor Pressure Deficit (VPD). In addition, we will evaluate drought response to as function of the Fraction of the Photosynthetic Active Radiation (FPAR), and the Normalized Difference Vegetation Index (NDVI). Our work is conducted at the Santa Rosa Environmental Monitoring Super Site (NR-EMSS) located at the Guancaste Province, Costa Rica, Central America. Our results indicate significant changes in terms of FPAR, VPD manifested via strong changes on NDVI. Our results pose questions about the resilience of these understudied tropical ecosystems and their long-term survival under severe and persistent drought conditions. This results provide a reference framework for the need of more integrated research on the Central American Dry Forest corridor where just between Costa Rica and Nicaragua over 100,000 families are facing strong drought conditions.

  3. Design and Experimental Evaluation on an Advanced Multisource Energy Harvesting System for Wireless Sensor Nodes

    PubMed Central

    Li, Hao; Zhang, Gaofei; Ma, Rui; You, Zheng

    2014-01-01

    An effective multisource energy harvesting system is presented as power supply for wireless sensor nodes (WSNs). The advanced system contains not only an expandable power management module including control of the charging and discharging process of the lithium polymer battery but also an energy harvesting system using the maximum power point tracking (MPPT) circuit with analog driving scheme for the collection of both solar and vibration energy sources. Since the MPPT and the power management module are utilized, the system is able to effectively achieve a low power consumption. Furthermore, a super capacitor is integrated in the system so that current fluctuations of the lithium polymer battery during the charging and discharging processes can be properly reduced. In addition, through a simple analog switch circuit with low power consumption, the proposed system can successfully switch the power supply path according to the ambient energy sources and load power automatically. A practical WSNs platform shows that efficiency of the energy harvesting system can reach about 75–85% through the 24-hour environmental test, which confirms that the proposed system can be used as a long-term continuous power supply for WSNs. PMID:25032233

  4. Novel Modified Optical Fibers for High Temperature In-Situ Miniaturized Gas Sensors in Advanced Fossil Energy Systems

    SciTech Connect

    Pickrell, Gary; Scott, Brian

    2014-06-30

    This report covers the technical progress on the program “Novel Modified Optical Fibers for High Temperature In-Situ Miniaturized Gas Sensors in Advanced Fossil Energy Systems”, funded by the National Energy Technology Laboratory of the U.S. Department of Energy, and performed by the Materials Science & Engineering and Electrical & Computer Engineering Departments at Virginia Tech, and summarizes technical progress from July 1st, 2005 –June 30th, 2014. The objective of this program was to develop novel fiber materials for high temperature gas sensors based on evanescent wave absorption in optical fibers. This project focused on two primary areas: the study of a sapphire photonic crystal fiber (SPCF) for operation at high temperature and long wavelengths, and a porous glass based fiber optic sensor for gas detection. The sapphire component of the project focused on the development of a sapphire photonic crystal fiber, modeling of the new structures, fabrication of the optimal structure, development of a long wavelength interrogation system, testing of the optical properties, and gas and temperature testing of the final sensor. The fabrication of the 6 rod SPCF gap bundle (diameter of 70μm) with a hollow core was successfully constructed with lead-in and lead-out 50μm diameter fiber along with transmission and gas detection testing. Testing of the sapphire photonic crystal fiber sensor capabilities with the developed long wavelength optical system showed the ability to detect CO2 at or below 1000ppm at temperatures up to 1000°C. Work on the porous glass sensor focused on the development of a porous clad solid core optical fiber, a hollow core waveguide, gas detection capabilities at room and high temperature, simultaneous gas species detection, suitable joining technologies for the lead-in and lead-out fibers and the porous sensor, sensor system sensitivity improvement, signal processing improvement, relationship between pore structure and fiber

  5. An overview of the measurements of soil moisture and modeling of moisture flux in FIFE

    NASA Technical Reports Server (NTRS)

    Wang, J. R.

    1992-01-01

    Measurements of soil moisture and calculations of moisture transfer in the soil medium and at the air-soil interface were performed over a 15-km by 15-km test site during FIFE in 1987 and 1989. The measurements included intensive soil moisture sampling at the ground level and surveys at aircraft altitudes by several passive and active microwave sensors as well as a gamma radiation device.

  6. Intercomparison of AMSR2 and AMSR-E Soil Moisture Retrievals with MERRA-L data set over Australia

    NASA Astrophysics Data System (ADS)

    Cho, E.; Choi, M.; Su, C. H.; Ryu, D.; Kim, H.; Jacobs, J. M.

    2015-12-01

    Soil moisture is an important variable in the hydrological cycle on the land surface and plays an essential role in hydrological and meteorological processes. The Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E) sensor on board the Aqua satellite offered valuable soil moisture data set from June 2002 and October 2011 and has been used in a wide range of applications. However, the AMSR-E sensor stopped operation from 4 October 2011 due to a problem with its antenna. AMSR-E was replaced by the Advanced Microwave Scanning Radiometer 2 (AMSR2) on the Global Climate Change Observation Mission 1 - Water (GCOM-W1) satellite in May 2012. Assessment of AMSR2 soil moisture retrievals as compared to AMSR-E has not yet been extensively evaluated. This task is critical if AMSR2 soil moisture products are used as a continuous dataset continuing the legacy of AMSR-E. The purpose of this study is to inter-compare AMSR2 and AMSR-E microwave based soil moisture over Australia, mediated by using model-based soil moisture data set to determine statistically similar inter-comparison periods from time periods of the individual sensors. This work use NASA-VUA AMSR2 and AMSR-E based soil moisture products derived by the Land Parameter Retrieval Model (LPRM) and the modelled soil moisture from NASA's MERRA-L (Modern Era Retrospective-analysis for Research and Applications-Land) re-analysis. The satellite soil moisture products are compared against the MERRA-L using traditional metrics, and the random errors in individual products are estimated using lagged instrumental variable regression analysis. Generally, the results demonstrate that the two satellite-based soil moisture retrievals have reasonable agreement with MERRA-L soil moisture data set. The error differences are notable, with the zonal error statistics are higher for AMSR2 in all climate zones, though the error maps of AMSR2 and AMSR-E are spatially similar over the Australia regions. This study leads

  7. Soil Moisture Experiments 2004 and 2005 Results and Plans

    NASA Astrophysics Data System (ADS)

    Jackson, T. J.

    2005-05-01

    The Soil Moisture Experiments (SMEX) series of field campaigns was designed to address research priorities of several programs involving satellite remote sensing of surface soil moisture. These include the Advanced Scanning Microwave Radiometer (AMSR) on Aqua, the Windsat on Coriolis, and future missions that include NASAs Hydros, the European Space Agency Soil Moisture Ocean Salinity (SMOS) mission and NPOESS. Algorithms, scaling, technology and land-atmosphere studies have all been addressed in each experiment. Scaling is a key aspect of experiment design because of the spatial differences between ground point observations and satellite footprints. In all of the campaigns aircraft sensors have provided the critical link between these. Different geographic domains have been used to provide diverse conditions for algorithm development and validation and a variety of aircraft instruments have been used to support specific objectives. SMEX04 was conducted in August 2004 in the southwestern U.S. and northern Mexico. It was designed to address satellite footprint heterogeneity. The region has the diverse topography, vegetation and rainfall patterns necessary to address this issue. In addition, SMEX04 was timed to coincide with North American Monsoon Experiment (NAME). A working hypothesis of NAME is that among the land surface antecedent boundary conditions that control the onset and intensity of the precipitation is soil moisture. Surface soil moisture can change dramatically after rain events. A review of SMEX04 and preliminary results will be presented. SMEX05 is being planned to understand what contributions to soil moisture retrieval and mapping may be achieved by using fully polarimetric passive microwave observations. This has not been a focus of land parameter investigations in the past. The Windsat instrument provides these measurements at several frequencies. For SMEX05 an aircraft simulator of Windsat will also be employed. The field campaign will be

  8. Development of equilibrium moisture relationships for storage moisture monitoring of corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Commercial systems are currently available to measure grain moisture during storage using relative humidity and temperature sensors and equilibrium moisture, EMC, models. However, the variability of the EMC relationships between grain lots necessitates that a good model needs to be selected or deve...

  9. Development of advanced high-temperature heat flux sensors. Phase 2: Verification testing

    NASA Technical Reports Server (NTRS)

    Atkinson, W. H.; Cyr, M. A.; Strange, R. R.

    1985-01-01

    A two-phase program is conducted to develop heat flux sensors capable of making heat flux measurements throughout the hot section of gas turbine engines. In Phase 1, three types of heat flux sensors are selected; embedded thermocouple, laminated, and Gardon gauge sensors. A demonstration of the ability of these sensors to operate in an actual engine environment is reported. A segmented liner of each of two combustors being used in the Broad Specification Fuels Combustor program is instrumented with the three types of heat flux sensors then tested in a high pressure combustor rig. Radiometer probes are also used to measure the radiant heat loads to more fully characterize the combustor environment. Test results show the heat flux sensors to be in good agreement with radiometer probes and the predicted data trends. In general, heat flux sensors have strong potential for use in combustor development programs.

  10. Sensor-model prediction, monitoring and in-situ control of liquid RTM advanced fiber architecture composite processing

    NASA Astrophysics Data System (ADS)

    Kranbuehl, D.; Kingsley, P.; Hart, S.; Loos, A.; Hasko, G.; Dexter, B.

    In-situ frequency dependent electromagnetic sensors (FDEMS) and the Loos resin transfer model have been used to select and control the processing properties of an epoxy resin during liquid pressure RTM impregnation and cure. Once correlated with viscosity and degree of cure the FDEMS sensor monitors and the RTM processing model predicts the reaction advancement of the resin, viscosity and the impregnation of the fabric. This provides a direct means for predicting, monitoring, and controlling the liquid RTM process in-situ in the mold throughout the fabrication process and the effects of time, temperature, vacuum and pressure. Most importantly, the FDEMS-sensor model system has been developed to make intelligent decisions, thereby automating the liquid RTM process and removing the need for operator direction.

  11. Sensor-model prediction, monitoring and in-situ control of liquid RTM advanced fiber architecture composite processing

    NASA Technical Reports Server (NTRS)

    Kranbuehl, D.; Kingsley, P.; Hart, S.; Loos, A.; Hasko, G.; Dexter, B.

    1992-01-01

    In-situ frequency dependent electromagnetic sensors (FDEMS) and the Loos resin transfer model have been used to select and control the processing properties of an epoxy resin during liquid pressure RTM impregnation and cure. Once correlated with viscosity and degree of cure the FDEMS sensor monitors and the RTM processing model predicts the reaction advancement of the resin, viscosity and the impregnation of the fabric. This provides a direct means for predicting, monitoring, and controlling the liquid RTM process in-situ in the mold throughout the fabrication process and the effects of time, temperature, vacuum and pressure. Most importantly, the FDEMS-sensor model system has been developed to make intelligent decisions, thereby automating the liquid RTM process and removing the need for operator direction.

  12. Advances in Hydrogen, Carbon Dioxide, and Hydrocarbon Gas Sensor Technology Using GaN and ZnO-Based Devices

    PubMed Central

    Anderson, Travis; Ren, Fan; Pearton, Stephen; Kang, Byoung Sam; Wang, Hung-Ta; Chang, Chih-Yang; Lin, Jenshan

    2009-01-01

    In this paper, we review our recent results in developing gas sensors for hydrogen using various device structures, including ZnO nanowires and GaN High Electron Mobility Transistors (HEMTs). ZnO nanowires are particularly interesting because they have a large surface area to volume ratio, which will improve sensitivity, and because they operate at low current levels, will have low power requirements in a sensor module. GaN-based devices offer the advantage of the HEMT structure, high temperature operation, and simple integration with existing fabrication technology and sensing systems. Improvements in sensitivity, recoverability, and reliability are presented. Also reported are demonstrations of detection of other gases, including CO2 and C2H4 using functionalized GaN HEMTs. This is critical for the development of lab-on-a-chip type systems and can provide a significant advance towards a market-ready sensor application. PMID:22408548

  13. New Sensors for In-Pile Temperature Detection at the Advanced Test Reactor National Scientific User Facility

    SciTech Connect

    J. L. Rempe; D. L. Knudson; J. E. Daw; K. G. Condie; S. Curtis Wilkins

    2009-09-01

    The Department of Energy (DOE) designated the Advanced Test Reactor (ATR) as a National Scientific User Facility (NSUF) in April 2007 to support U.S. leadership in nuclear science and technology. As a user facility, the ATR is supporting new users from universities, laboratories, and industry, as they conduct basic and applied nuclear research and development to advance the nation’s energy security needs. A key component of the ATR NSUF effort is to develop and evaluate new in-pile instrumentation techniques that are capable of providing measurements of key parameters during irradiation. This paper describes the strategy for determining what instrumentation is needed and the program for developing new or enhanced sensors that can address these needs. Accomplishments from this program are illustrated by describing new sensors now available and under development for in-pile detection of temperature at various irradiation locations in the ATR.

  14. Using globally available soil moisture indicators for flood modelling in Mediterranean catchments

    NASA Astrophysics Data System (ADS)

    Massari, C.; Brocca, L.; Barbetta, S.; Papathanasiou, C.; Mimikou, M.; Moramarco, T.

    2013-08-01

    Floods are one of the most dangerous natural hazards in Mediterranean regions. Flood forecasting tools and early warning systems can be very beneficial to reduce flood risk. Event-based rainfall runoff models are frequently employed for operational flood forecasting purposes because of their simplicity and the reduced number of parameters involved with respect to continuous models. However, the advantages that are related with the reduced parameterization face against the need for a correct initialization of the model, especially in areas affected by strong climate seasonality. On the other hand, the use of continuous models may be very problematic in poorly gauged areas. This paper introduces a simplified continuous rainfall-runoff model, which uses globally available soil moisture retrievals to identify the initial wetness condition of the catchment, and, only event rainfall data to simulate discharge hydrographs. The model calibration involves only 3 parameters. For soil moisture, beside in situ and modelled data, satellite products from the Advanced SCATterometer (ASCAT) and the Advanced Microwave Scanning Radiometer for Earth observation (AMSR-E) sensors are employed. Additionally, the ERA-LAND reanalysis soil moisture product of the European Centre for Medium Range Weather Forecasting (ECMWF) is used. The model was tested in the small catchment of Rafina, 109 km2 located in the Eastern Attica region, Greece. Specifically, fifteen rainfall-runoff events were modelled by considering different configurations for the initial soil moisture conditions. Comparing the performance of the different soil moisture products, it was found that all global indicators allow reproducing fairly well the selected flood events providing much better results than the situation where a constant initial condition is provided. ERA-LAND slightly outperforms the satellite soil moisture products and in general, all the indicators give the same performance obtained by ground and

  15. Evaluation of satellite soil moisture products over Norway using ground-based observations

    NASA Astrophysics Data System (ADS)

    Griesfeller, A.; Lahoz, W. A.; Jeu, R. A. M. de; Dorigo, W.; Haugen, L. E.; Svendby, T. M.; Wagner, W.

    2016-03-01

    In this study we evaluate satellite soil moisture products from the advanced SCATterometer (ASCAT) and the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) over Norway using ground-based observations from the Norwegian water resources and energy directorate. The ASCAT data are produced using the change detection approach of Wagner et al. (1999), and the AMSR-E data are produced using the VUA-NASA algorithm (Owe et al., 2001, 2008). Although satellite and ground-based soil moisture data for Norway have been available for several years, hitherto, such an evaluation has not been performed. This is partly because satellite measurements of soil moisture over Norway are complicated owing to the presence of snow, ice, water bodies, orography, rocks, and a very high coastline-to-area ratio. This work extends the European areas over which satellite soil moisture is validated to the Nordic regions. Owing to the challenging conditions for soil moisture measurements over Norway, the work described in this paper provides a stringent test of the capabilities of satellite sensors to measure soil moisture remotely. We show that the satellite and in situ data agree well, with averaged correlation (R) values of 0.72 and 0.68 for ASCAT descending and ascending data vs in situ data, and 0.64 and 0.52 for AMSR-E descending and ascending data vs in situ data for the summer/autumn season (1 June-15 October), over a period of 3 years (2009-2011). This level of agreement indicates that, generally, the ASCAT and AMSR-E soil moisture products over Norway have high quality, and would be useful for various applications, including land surface monitoring, weather forecasting, hydrological modelling, and climate studies. The increasing emphasis on coupled approaches to study the earth system, including the interactions between the land surface and the atmosphere, will benefit from the availability of validated and improved soil moisture satellite datasets, including those

  16. A real-time simulation evaluation of an advanced detection, isolation and accommodation algorithm for sensor failures in turbine engines

    NASA Technical Reports Server (NTRS)

    Merrill, W. C.; Delaat, J. C.

    1986-01-01

    An advanced sensor failure detection, isolation, and accommodation (ADIA) algorithm has been developed for use with an aircraft turbofan engine control system. In a previous paper the authors described the ADIA algorithm and its real-time implementation. Subsequent improvements made to the algorithm and implementation are discussed, and the results of an evaluation presented. The evaluation used a real-time, hybrid computer simulation of an F100 turbofan engine.

  17. A real-time simulation evaluation of an advanced detection. Isolation and accommodation algorithm for sensor failures in turbine engines

    NASA Technical Reports Server (NTRS)

    Merrill, W. C.; Delaat, J. C.

    1986-01-01

    An advanced sensor failure detection, isolation, and accommodation (ADIA) algorithm has been developed for use with an aircraft turbofan engine control system. In a previous paper the authors described the ADIA algorithm and its real-time implementation. Subsequent improvements made to the algorithm and implementation are discussed, and the results of an evaluation presented. The evaluation used a real-time, hybrid computer simulation of an F100 turbofan engine.

  18. Multispectral sensing of moisture stress

    NASA Technical Reports Server (NTRS)

    Olson, C. E., Jr.

    1970-01-01

    Laboratory reflectance data, and field tests with multispectral remote sensors provide support for this hypotheses that differences in moisture content and water deficits are closely related to foliar reflectance from woody plants. When these relationships are taken into account, automatic recognition techniques become more powerful than when they are ignored. Evidence is increasing that moisture relationships inside plant foliage are much more closely related to foliar reflectance characteristics than are external variables such as soil moisture, wind, and air temperature. Short term changes in water deficits seem to have little influence on foliar reflectance, however. This is in distinct contrast to significant short-term changes in foliar emittance from the same plants with changing wind, air temperature, incident radiation, or water deficit conditions.

  19. ASCAT soil moisture data assimilation in the local area model ALADIN

    NASA Astrophysics Data System (ADS)

    Schneider, S.

    2010-09-01

    Soil moisture is crucial for all biological life on land and controls the energy, water and carbon fluxes at the land surface, thus influencing the weather. Therefore, knowledge about the soil moisture distribution is of large interest for weather forecasting, flood and drought monitoring, and civil protection. Investigations are showing that the spatial and temporal distribution of soil moisture in mid-latitudes has important implications especially for the summertime convective precipitation distribution. In general, higher levels of soil moisture and evapotranspiration lead to higher levels of precipitation due to feedback mechanisms. To determine the soil moisture distribution, the field of microwave remote sensing has been an important research topic since the 1970s, but only in the last few years significant progress towards operational soil moisture services has been made. This progress became possible due to advances in sensor technology and new algorithmic approaches. The first near-real-time (broadcasting within 130 minutes after sensing) soil moisture service was started by EUMETSAT in May 2008 based on METOP ASCAT scatterometer, providing soil moisture data on a 25km grid over Europe with a temporal coverage of about 1.5 days. While there are already several investigations about assimilation of these data to global forecast models resulting in small improvements of screen level parameters, ASCAT soil moisture assimilation in local area model (LAM) is a new scientific topic. For this purpose, the high resolution measurements are assimilated at the Austrian federal weather service ZAMG into its version of the local area model ALADIN. The main goal is the further improvement of the forecast quality, especially in convective situations, taking into account the complex topography in Austria. Data assimilation is executed with an extended Kalman filter (EKF) approach developed at Météo France and CNRM within the surface modelling system SURFEX. The

  20. Advanced activity reporting in a multi-layered unattended ground sensor network

    NASA Astrophysics Data System (ADS)

    Joslin, Todd W.

    2007-04-01

    Sensor networks are emplaced throughout the world to remotely track activity. Typically, these sensors report data such as target direction or target classification. This information is reported to a personnel-based monitor or a command and control center. The ideal sensor system will have a long mission life capability and will report information-rich actionable intelligence with high data integrity at near real-time latency. This paper discusses a multi-layered approach that includes data fusion at the Sensor Node, Sensor Field, and Command and Control Center Layer to create cohesive reports that mitigate false alarms and multiple reports of the same target while providing accurate tracking data on a situational awareness level. This approach is influenced by low-power architecture, and designed to maximize information density and reduce flooding of sensor networks.

  1. Moisture Research - Optimizing Wall Assemblies

    SciTech Connect

    Arena, L.; Mantha, P.

    2013-05-01

    The Consortium for Advanced Residential Buildings (CARB) evaluated several different configurations of wall assemblies to determine the accuracy of moisture modeling and make recommendations to ensure durable, efficient assemblies. WUFI and THERM were used to model the hygrothermal and heat transfer characteristics of these walls.

  2. Development of fiber optic sensors for advanced aircraft testing and control

    NASA Astrophysics Data System (ADS)

    Meller, Scott A.; Jones, Mark E.; Wavering, Thomas A.; Kozikowski, Carrie L.; Murphy, Kent A.

    1999-02-01

    Optical fiber sensors, because of the small size, low weight, extremely high information carrying capability, immunity to electromagnetic interference, and large operational temperature range, provide numerous advantages over conventional electrically based sensors. This paper presents preliminary results from optical fiber sensor design for monitoring acceleration on aircraft. Flight testing of the final accelerometer design will be conducted on the F-18 Systems Research Aircraft at NASA Dryden Flight Research Center in Edwards, CA.

  3. Generation of large scale urban environments to support advanced sensor and seeker simulation

    NASA Astrophysics Data System (ADS)

    Giuliani, Joseph; Hershey, Daniel; McKeown, David, Jr.; Willis, Carla; Van, Tan

    2009-05-01

    One of the key aspects for the design of a next generation weapon system is the need to operate in cluttered and complex urban environments. Simulation systems rely on accurate representation of these environments and require automated software tools to construct the underlying 3D geometry and associated spectral and material properties that are then formatted for various objective seeker simulation systems. Under an Air Force Small Business Innovative Research (SBIR) contract, we have developed an automated process to generate 3D urban environments with user defined properties. These environments can be composed from a wide variety of source materials, including vector source data, pre-existing 3D models, and digital elevation models, and rapidly organized into a geo-specific visual simulation database. This intermediate representation can be easily inspected in the visible spectrum for content and organization and interactively queried for accuracy. Once the database contains the required contents, it can then be exported into specific synthetic scene generation runtime formats, preserving the relationship between geometry and material properties. To date an exporter for the Irma simulation system developed and maintained by AFRL/Eglin has been created and a second exporter to Real Time Composite Hardbody and Missile Plume (CHAMP) simulation system for real-time use is currently being developed. This process supports significantly more complex target environments than previous approaches to database generation. In this paper we describe the capabilities for content creation for advanced seeker processing algorithms simulation and sensor stimulation, including the overall database compilation process and sample databases produced and exported for the Irma runtime system. We also discuss the addition of object dynamics and viewer dynamics within the visual simulation into the Irma runtime environment.

  4. On-chip polarizer on image sensor using advanced CMOS technology

    NASA Astrophysics Data System (ADS)

    Sasagawa, Kiyotaka; Wakama, Norimitsu; Noda, Toshihiko; Tokuda, Takashi; Kakiuchi, Kiyomi; Ohta, Jun

    2014-03-01

    The structures in advanced complementary metal-oxide-semiconductor (CMOS) integrated circuit technology are in the range of deep-submicron. It allows designing and integrating nano-photonic structures for the visible to near infrared region on a chip. In this work, we designed and fabricated an image sensor with on-pixel metal wire grid polarizers by using a 65-nm standard CMOS technology. It is known that the extinction ratio of a metal wire grid polarizer is increased with decrease in the grid pitch. With the metal wire layers of the 65-nm technology, the grid pitch sufficiently smaller than the wavelengths of visible light can be realized. The extinction ratio of approximately 20 dB has been successfully achieved at a wavelength of 750 nm. In the CMOS technologies, it is usual to include multiple metal layers. This feature is also useful to increase the extinction ratio of polarizers. We designed dual layer polarizers. Each layer partially reflects incident light. Thus, the layers form a cavity and its transmission spectrum depends on the layer position. The extinction ratio of 19.2 dB at 780 nm was achieved with the grid pitch greater than the single layer polarizer. The high extinction ratio is obtained only red to near infrared region because the fine metal layers of deepsubmicron standard CMOS process is usually composed of Cu. Thus, it should be applied for measurement or observation where wide spectrum is not required such as optical rotation measurement of optically active materials or electro-optic imaging of RF/THz wave.

  5. Sensor probes and phantoms for advanced transcranial magnetic stimulation system developments

    NASA Astrophysics Data System (ADS)

    Meng, Qinglei; Patel, Prashil; Trivedi, Sudhir; Du, Xiaoming; Hong, Elliot; Choa, Fow-Sen

    2015-05-01

    Transcranial magnetic stimulation (TMS) has become one of the most widely used noninvasive method for brain tissue stimulation and has been used as a treatment tool for various neurological and psychiatric disorders including migraine, stroke, Parkinson's disease, dystonia, tinnitus and depression. In the process of developing advanced TMS deep brain stimulation tools, we need first to develop field measurement devices like sensory probes and brain phantoms, which can be used to calibrate the TMS systems. Currently there are commercially available DC magnetic or electric filed measurement sensors, but there is no instrument to measure transient fields. In our study, we used a commercial figure-8 shaped TMS coil to generate transient magnetic field and followed induced field and current. The coil was driven by power amplified signal from a pulse generator with tunable pulse rate, amplitude, and duration. In order to obtain a 3D plot of induced vector electric field, many types of probes were designed to detect single component of electric-field vectors along x, y and z axis in the space around TMS coil. We found that resistor probes has an optimized signal-to-noise ratio (SNR) near 3k ohm but it signal output is too weak compared with other techniques. We also found that inductor probes can have very high output for Curl E measurement, but it is not the E-field distribution we are interested in. Probes with electrical wire wrapped around iron coil can directly measure induced E-field with high sensitivity, which matched computer simulation results.

  6. Validation of two gridded soil moisture products over India with in-situ observations

    NASA Astrophysics Data System (ADS)

    Unnikrishnan, C. K.; George, John P.; Lodh, Abhishek; Maurya, Devesh Kumar; Mallick, Swapan; Rajagopal, E. N.; Mohandas, Saji

    2016-07-01

    Surface level soil moisture from two gridded datasets over India are evaluated in this study. The first one is the UK Met Office (UKMO) soil moisture analysis produced by a land data assimilation system based on Extended Kalman Filter method (EKF), which make use of satellite observation of Advanced Scatterometer (ASCAT) soil wetness index as well as the screen level meteorological observations. Second dataset is a satellite soil moisture product, produced by National Remote Sensing Centre (NRSC) using passive microwave Advanced Microwave Scanning Radiometer 2 measurements. In-situ observations of soil moisture from India Meteorological Department (IMD) are used for the validation of the gridded soil moisture products. The difference between these datasets over India is minimum in the non-monsoon months and over agricultural regions. It is seen that the NRSC data is slightly drier (0.05%) and UKMO soil moisture analysis is relatively wet during southwest monsoon season. Standard AMSR-2 satellite soil moisture product is used to compare the NRSC and UKMO products. The standard AMSR-2 and UKMO values are closer in monsoon season and AMSR-2 soil moisture is higher than UKMO in all seasons. NRSC and AMSR-2 showed a correlation of 0.83 (significant at 0.01 level). The probability distribution of IMD soil moisture observation peaks at 0.25 m3/m3, NRSC at 0.15 m3/m3, AMSR-2 at 0.25 m3/m3 and UKMO at 0.35 m3/m3 during June-September period. Validation results show UKMO analysis has better correlation with in-situ observations compared to the NRSC and AMSR-2 datasets. The seasonal variation in soil moisture is better represented in UKMO analysis. Underestimation of soil moisture during monsoon season over India in NRSC data suggests the necessity of incorporating the actual vegetation for a better soil moisture retrieval using passive microwave sensors. Both products have good agreement over bare soil, shrubs and grassland compared to needle leaf tree, broad leaf tree and

  7. Estimating Soil Moisture Distributions across Small Farm Fields with ALOS/PALSAR

    PubMed Central

    Oki, Kazuo

    2016-01-01

    The ALOS (advanced land observing satellite) has an active microwave sensor, PALSAR (phased array L-band synthetic aperture radar), which has a fine resolution of 6.5 m. Because of the fine resolution, PALSAR provides the possibility of estimating soil moisture distributions in small farmlands. Making such small-scale estimates has not been available with traditional satellite remote sensing techniques. In this study, the relationship between microwave backscattering coefficient (σ) measured with PALSAR and ground-based soil moisture was determined to investigate the performance of PALSAR for estimating soil moisture distribution in a small-scale farmland. On the ground at a cabbage field in Japan in 2008, the soil moisture distribution of multiple soil layers was measured using time domain reflectometry when the ALOS flew over the field. Soil moisture in the 0–20 cm soil layer showed the largest correlation coefficient with σ (r = 0.403). The σ values also showed a strong correlation with the ground surface coverage ratio by cabbage plants. Our results suggested that PALSAR could estimate soil moisture distribution of the 0–20 cm soil layer across a bare field and a crop coverage ratio when crops were planted. PMID:27529080

  8. Estimating Soil Moisture Distributions across Small Farm Fields with ALOS/PALSAR.

    PubMed

    Kojima, Yuki; Oki, Kazuo; Noborio, Kosuke; Mizoguchi, Masaru

    2016-01-01

    The ALOS (advanced land observing satellite) has an active microwave sensor, PALSAR (phased array L-band synthetic aperture radar), which has a fine resolution of 6.5 m. Because of the fine resolution, PALSAR provides the possibility of estimating soil moisture distributions in small farmlands. Making such small-scale estimates has not been available with traditional satellite remote sensing techniques. In this study, the relationship between microwave backscattering coefficient (σ) measured with PALSAR and ground-based soil moisture was determined to investigate the performance of PALSAR for estimating soil moisture distribution in a small-scale farmland. On the ground at a cabbage field in Japan in 2008, the soil moisture distribution of multiple soil layers was measured using time domain reflectometry when the ALOS flew over the field. Soil moisture in the 0-20 cm soil layer showed the largest correlation coefficient with σ (r = 0.403). The σ values also showed a strong correlation with the ground surface coverage ratio by cabbage plants. Our results suggested that PALSAR could estimate soil moisture distribution of the 0-20 cm soil layer across a bare field and a crop coverage ratio when crops were planted. PMID:27529080

  9. SOIL moisture data intercomparison

    NASA Astrophysics Data System (ADS)

    Kerr, Yann; Rodriguez-Frenandez, Nemesio; Al-Yaari, Amen; Parens, Marie; Molero, Beatriz; Mahmoodi, Ali; Mialon, Arnaud; Richaume, Philippe; Bindlish, Rajat; Mecklenburg, Susanne; Wigneron, Jean-Pierre

    2016-04-01

    The Soil Moisture and Ocean Salinity satellite (SMOS) was launched in November 2009 and started delivering data in January 2010. Subsequently, the satellite has been in operation for over 6 years while the retrieval algorithms from Level 1 to Level 2 underwent significant evolutions as knowledge improved. Other approaches for retrieval at Level 2 over land were also investigated while Level 3 and 4 were initiated. In this présentation these improvements are assessed by inter-comparisons of the current Level 2 (V620) against the previous version (V551) and new products either using neural networks or Level 3. In addition a global evaluation of different SMOS soil moisture (SM) products is performed comparing products with those of model simulations and other satellites (AMSR E/ AMSR2 and ASCAT). Finally, all products were evaluated against in situ measurements of soil moisture (SM). The study demonstrated that the V620 shows a significant improvement (including those at level1 improving level2)) with respect to the earlier version V551. Results also show that neural network based approaches can yield excellent results over areas where other products are poor. Finally, global comparison indicates that SMOS behaves very well when compared to other sensors/approaches and gives consistent results over all surfaces from very dry (African Sahel, Arizona), to wet (tropical rain forests). RFI (Radio Frequency Interference) is still an issue even though detection has been greatly improved while RFI sources in several areas of the world are significantly reduced. When compared to other satellite products, the analysis shows that SMOS achieves its expected goals and is globally consistent over different eco climate regions from low to high latitudes and throughout the seasons.

  10. Advanced Packaging Technology Used in Fabricating a High-Temperature Silicon Carbide Pressure Sensor

    NASA Technical Reports Server (NTRS)

    Beheim, Glenn M.

    2003-01-01

    The development of new aircraft engines requires the measurement of pressures in hot areas such as the combustor and the final stages of the compressor. The needs of the aircraft engine industry are not fully met by commercially available high-temperature pressure sensors, which are fabricated using silicon. Kulite Semiconductor Products and the NASA Glenn Research Center have been working together to develop silicon carbide (SiC) pressure sensors for use at high temperatures. At temperatures above 850 F, silicon begins to lose its nearly ideal elastic properties, so the output of a silicon pressure sensor will drift. SiC, however, maintains its nearly ideal mechanical properties to extremely high temperatures. Given a suitable sensor material, a key to the development of a practical high-temperature pressure sensor is the package. A SiC pressure sensor capable of operating at 930 F was fabricated using a newly developed package. The durability of this sensor was demonstrated in an on-engine test. The SiC pressure sensor uses a SiC diaphragm, which is fabricated using deep reactive ion etching. SiC strain gauges on the surface of the diaphragm sense the pressure difference across the diaphragm. Conventionally, the SiC chip is mounted to the package with the strain gauges outward, which exposes the sensitive metal contacts on the chip to the hostile measurement environment. In the new Kulite leadless package, the SiC chip is flipped over so that the metal contacts are protected from oxidation by a hermetic seal around the perimeter of the chip. In the leadless package, a conductive glass provides the electrical connection between the pins of the package and the chip, which eliminates the fragile gold wires used previously. The durability of the leadless SiC pressure sensor was demonstrated when two 930 F sensors were tested in the combustor of a Pratt & Whitney PW4000 series engine. Since the gas temperatures in these locations reach 1200 to 1300 F, the sensors were

  11. Use of an autonomous sensor to evaluate the biological performance of the advanced turbine at Wanapum Dam

    SciTech Connect

    Deng, Zhiqun; Carlson, Thomas J.; Duncan, Joanne P.; Richmond, Marshall C.; Dauble, Dennis D.

    2010-10-13

    Hydropower is the largest renewable energy resource in the United States and the world. However, hydropower dams have adverse ecological impacts because migrating fish may be injured or killed when they pass through hydroturbines. In the Columbia and Snake River basins, dam operators and engineers are required to make those hydroelectric facilities more fish-friendly through changes in hydroturbine design and operation after fish population declines and the subsequent listing of several species of Pacific salmon under the Endangered Species Act of 1973. Public Utility District No. 2 of Grant County, Washington, requested authorization from the Federal Energy Regulatory Commission to replace the ten turbines at Wanapum Dam with advanced hydropower turbines designed to improve survival for fish passing through the turbines while improving operation efficiency and increasing power generation. As an additional measure to the primary metric of direct injury and mortality rates of juvenile Chinook salmon using balloon tag-recapture methodology, this study used an autonomous sensor device - the Sensor Fish - to provide insight into the specific hydraulic conditions and physical stresses experienced by the fish as well as the specific causes of fish biological response. We found that the new hydroturbine blade shape and the corresponding reduction of turbulence in the advanced hydropower turbine were effective in meeting the objectives of improving fish survival while enhancing operational efficiency of the dam. The frequency of severe events based on Sensor Fish pressure and acceleration measurements showed trends similar to those of fish survival determined by the balloon tag-recapture methodology. In addition, the new turbine provided a better pressure and rate of pressure change environment for fish passage. Altogether, the Sensor Fish data indicated that the advanced hydroturbine design improved passage of juvenile salmon at Wanapum Dam.

  12. Use of an autonomous sensor to evaluate the biological performance of the advanced turbine at Wanapum Dam

    DOE PAGESBeta

    Deng, Zhiqun; Carlson, Thomas J.; Duncan, Joanne P.; Richmond, Marshall C.; Dauble, Dennis D.

    2010-10-13

    Hydropower is the largest renewable energy resource in the United States and the world. However, hydropower dams have adverse ecological impacts because migrating fish may be injured or killed when they pass through hydroturbines. In the Columbia and Snake River basins, dam operators and engineers are required to make those hydroelectric facilities more fish-friendly through changes in hydroturbine design and operation after fish population declines and the subsequent listing of several species of Pacific salmon under the Endangered Species Act of 1973. Public Utility District No. 2 of Grant County, Washington, requested authorization from the Federal Energy Regulatory Commission tomore » replace the ten turbines at Wanapum Dam with advanced hydropower turbines designed to improve survival for fish passing through the turbines while improving operation efficiency and increasing power generation. As an additional measure to the primary metric of direct injury and mortality rates of juvenile Chinook salmon using balloon tag-recapture methodology, this study used an autonomous sensor device - the Sensor Fish - to provide insight into the specific hydraulic conditions and physical stresses experienced by the fish as well as the specific causes of fish biological response. We found that the new hydroturbine blade shape and the corresponding reduction of turbulence in the advanced hydropower turbine were effective in meeting the objectives of improving fish survival while enhancing operational efficiency of the dam. The frequency of severe events based on Sensor Fish pressure and acceleration measurements showed trends similar to those of fish survival determined by the balloon tag-recapture methodology. In addition, the new turbine provided a better pressure and rate of pressure change environment for fish passage. Altogether, the Sensor Fish data indicated that the advanced hydroturbine design improved passage of juvenile salmon at Wanapum Dam.« less

  13. Advances towards the qualification of an aircraft fuel tank inert environment fiber optic oxygen sensor system

    NASA Astrophysics Data System (ADS)

    Mendoza, Edgar A.; Esterkin, Yan; Kempen, Cornelia; Sun, Songjian; Susko, Kenneth; Goglia, John

    2011-06-01

    An all optical pressure and temperature compensated fiber optic oxygen sensor (FOxSenseTM) system is under qualification for use in the in-situ closed-loop-control of the inert atmosphere environment inside fuel tanks of military and commercial aircraft. The all-optical oxygen environment control sensor is a passive, intrinsically safe, fiber-optic sensor device with no electrical connections leading to the sensors installed within the fuel tanks of an aircraft. To control the fuel tank environment, an array of multiple sensors is deployed throughout the fuel tanks of an aircraft, and a remote multi-channel optoelectronic system is used to monitor the status of all the sensors in real time to provide feedback oxygen environment information to the on-board inert gas generating system (OBIGS). Qualification testing of the all optical sensor have demonstrated the ability to monitor the oxygen environment inside a simulated fuel tank environment in the oxygen range from 0% to 21% oxygen concentrations, temperatures from (-) 40°C to (+) 60°C, and altitudes from sea level to 40,000 feet. Fiber optic oxygen sensors with built-in temperature compensation as well as the conduit fiber optic cables have passed DO-160E including acoustic noise and burn test.

  14. A real-time implementation of an advanced sensor failure detection, isolation, and accommodation algorithm

    NASA Technical Reports Server (NTRS)

    Delaat, J. C.; Merrill, W. C.

    1983-01-01

    A sensor failure detection, isolation, and accommodation algorithm was developed which incorporates analytic sensor redundancy through software. This algorithm was implemented in a high level language on a microprocessor based controls computer. Parallel processing and state-of-the-art 16-bit microprocessors are used along with efficient programming practices to achieve real-time operation.

  15. SMOS soil moisture validation with U.S. in situ newworks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Estimation of soil moisture at large scale has been performed using several satellite-based passive microwave sensors using a variety of retrieval methods. The most recent source of soil moisture is the European Space Agency Soil Moisture and Ocean Salinity (SMOS) mission. Since it is a new sensor u...

  16. Advanced Interrogation of Fiber-Optic Bragg Grating and Fabry-Perot Sensors with KLT Analysis

    PubMed Central

    Tosi, Daniele

    2015-01-01

    The Karhunen-Loeve Transform (KLT) is applied to accurate detection of optical fiber sensors in the spectral domain. By processing an optical spectrum, although coarsely sampled, through the KLT, and subsequently processing the obtained eigenvalues, it is possible to decode a plurality of optical sensor results. The KLT returns higher accuracy than other demodulation techniques, despite coarse sampling, and exhibits higher resilience to noise. Three case studies of KLT-based processing are presented, representing most of the current challenges in optical fiber sensing: (1) demodulation of individual sensors, such as Fiber Bragg Gratings (FBGs) and Fabry-Perot Interferometers (FPIs); (2) demodulation of dual (FBG/FPI) sensors; (3) application of reverse KLT to isolate different sensors operating on the same spectrum. A simulative outline is provided to demonstrate the KLT operation and estimate performance; a brief experimental section is also provided to validate accurate FBG and FPI decoding. PMID:26528975

  17. Advanced Interrogation of Fiber-Optic Bragg Grating and Fabry-Perot Sensors with KLT Analysis.

    PubMed

    Tosi, Daniele

    2015-01-01

    The Karhunen-Loeve Transform (KLT) is applied to accurate detection of optical fiber sensors in the spectral domain. By processing an optical spectrum, although coarsely sampled, through the KLT, and subsequently processing the obtained eigenvalues, it is possible to decode a plurality of optical sensor results. The KLT returns higher accuracy than other demodulation techniques, despite coarse sampling, and exhibits higher resilience to noise. Three case studies of KLT-based processing are presented, representing most of the current challenges in optical fiber sensing: (1) demodulation of individual sensors, such as Fiber Bragg Gratings (FBGs) and Fabry-Perot Interferometers (FPIs); (2) demodulation of dual (FBG/FPI) sensors; (3) application of reverse KLT to isolate different sensors operating on the same spectrum. A simulative outline is provided to demonstrate the KLT operation and estimate performance; a brief experimental section is also provided to validate accurate FBG and FPI decoding. PMID:26528975

  18. Recent Advances of MEMS Resonators for Lorentz Force Based Magnetic Field Sensors: Design, Applications and Challenges.

    PubMed

    Herrera-May, Agustín Leobardo; Soler-Balcazar, Juan Carlos; Vázquez-Leal, Héctor; Martínez-Castillo, Jaime; Vigueras-Zuñiga, Marco Osvaldo; Aguilera-Cortés, Luz Antonio

    2016-01-01

    Microelectromechanical systems (MEMS) resonators have allowed the development of magnetic field sensors with potential applications such as biomedicine, automotive industry, navigation systems, space satellites, telecommunications and non-destructive testing. We present a review of recent magnetic field sensors based on MEMS resonators, which operate with Lorentz force. These sensors have a compact structure, wide measurement range, low energy consumption, high sensitivity and suitable performance. The design methodology, simulation tools, damping sources, sensing techniques and future applications of magnetic field sensors are discussed. The design process is fundamental in achieving correct selection of the operation principle, sensing technique, materials, fabrication process and readout systems of the sensors. In addition, the description of the main sensing systems and challenges of the MEMS sensors are discussed. To develop the best devices, researches of their mechanical reliability, vacuum packaging, design optimization and temperature compensation circuits are needed. Future applications will require multifunctional sensors for monitoring several physical parameters (e.g., magnetic field, acceleration, angular ratio, humidity, temperature and gases). PMID:27563912

  19. Rainfall estimation from soil moisture data: crash test for SM2RAIN algorithm

    NASA Astrophysics Data System (ADS)

    Brocca, Luca; Albergel, Clement; Massari, Christian; Ciabatta, Luca; Moramarco, Tommaso; de Rosnay, Patricia

    2015-04-01

    Soil moisture governs the partitioning of mass and energy fluxes between the land surface and the atmosphere and, hence, it represents a key variable for many applications in hydrology and earth science. In recent years, it was demonstrated that soil moisture observations from ground and satellite sensors contain important information useful for improving rainfall estimation. Indeed, soil moisture data have been used for correcting rainfall estimates from state-of-the-art satellite sensors (e.g. Crow et al., 2011), and also for improving flood prediction through a dual data assimilation approach (e.g. Massari et al., 2014; Chen et al., 2014). Brocca et al. (2013; 2014) developed a simple algorithm, called SM2RAIN, which allows estimating rainfall directly from soil moisture data. SM2RAIN has been applied successfully to in situ and satellite observations. Specifically, by using three satellite soil moisture products from ASCAT (Advanced SCATterometer), AMSR-E (Advanced Microwave Scanning Radiometer for Earth Observation) and SMOS (Soil Moisture and Ocean Salinity); it was found that the SM2RAIN-derived rainfall products are as accurate as state-of-the-art products, e.g., the real-time version of the TRMM (Tropical Rainfall Measuring Mission) product. Notwithstanding these promising results, a detailed study investigating the physical basis of the SM2RAIN algorithm, its range of applicability and its limitations on a global scale has still to be carried out. In this study, we carried out a crash test for SM2RAIN algorithm on a global scale by performing a synthetic experiment. Specifically, modelled soil moisture data are obtained from HTESSEL model (Hydrology Tiled ECMWF Scheme for Surface Exchanges over Land) forced by ERA-Interim near-surface meteorology. Afterwards, the modelled soil moisture data are used as input into SM2RAIN algorithm for testing weather or not the resulting rainfall estimates are able to reproduce ERA-Interim rainfall data. Correlation, root

  20. Recent Advances of Portable Multi-Sensor Technique of Volcanic Plume Measurement

    NASA Astrophysics Data System (ADS)

    Shinohara, H.

    2005-12-01

    A technique has been developed to estimate chemical composition volcanic gases based on the measurement of volcanic plumes at distance from a source vent by the use of a portable multi-sensor system consisting a humidity sensor, an SO2 electrochemical sensor and a CO2 IR analyzer (Shinohara, 2005). Since volcanic plume is a mixture of the atmosphere and volcanic gases, the volcanic gas composition can be estimated by subtracting the atmospheric background from the plume data. This technique enabled us to estimate concentration ratios of major volcanic gas species (i.e., H2O, CO2 and SO2) without any complicated chemical analyses even for gases emitted from an inaccessible open vent. Since the portable multi-sensor system was light (~ 5 kg) and small enough to carry in a medium size backpack, we could apply this technique to measure volcanic plumes at summit of various volcanoes including those which require us a tough climbing, such as Villarrica volcano, Chile. We further improved the sensor system and the measurements techniques, including application of LI-840 IR H2O and CO2 analyzer, H2S electrochemical sensor and H2 semi-conductor sensor. Application of the new LI-840 analyzer enabled us to measure H2O concentration in the plume with similar response time with CO2 concentration. The H2S electrochemical sensor of Komyo Co. has a chemical filter to removed SO2 to achieve a low sensitivity (0.1%) to SO2, and we can measure a high SO2/H2S ratio up to 1000. The semi-conductor sensor can measure H2 concentration in the range from the background level in the atmosphere (~0.5 ppm) to ~50 ppm. Response of the H2 sensor is slower (90% response time = ~90 sec) than other sensors in particular in low concentration range, and the measurement is still semi-quantitative with errors up to ±50%. The H2/H2O ratios are quite variable in volcanic gases ranging from less than 10-5 up to 10-1, and the ratio is largely controlled by temperature and pressure condition of the

  1. Optical fiber evanescent wave adsorption sensors for high-temperature gas sensing in advanced coal-fired power plants

    SciTech Connect

    Buric, M.; Ohodnicky, P.; Duy, J.

    2012-01-01

    Modern advanced energy systems such as coal-fired power plants, gasifiers, or similar infrastructure present some of the most challenging harsh environments for sensors. The power industry would benefit from new, ultra-high temperature devices capable of surviving in hot and corrosive environments for embedded sensing at the highest value locations. For these applications, we are currently exploring optical fiber evanescent wave absorption spectroscopy (EWAS) based sensors consisting of high temperature core materials integrated with novel high temperature gas sensitive cladding materials. Mathematical simulations can be used to assist in sensor development efforts, and we describe a simulation code that assumes a single thick cladding layer with gas sensitive optical constants. Recent work has demonstrated that Au nanoparticle-incorporated metal oxides show a potentially useful response for high temperature optical gas sensing applications through the sensitivity of the localized surface plasmon resonance absorption peak to ambient atmospheric conditions. Hence, the simulation code has been applied to understand how such a response can be exploited in an optical fiber based EWAS sensor configuration. We demonstrate that interrogation can be used to optimize the sensing response in such materials.

  2. Performance Diagnosis using Optical Torque Sensor for Selection of a Steam Supply Plant among Advanced Combined Cycle Power Plants

    NASA Astrophysics Data System (ADS)

    Umezawa, Shuichi

    A newly developed optical torque sensor was applied to select a steam supply plant among advanced combined cycle, i.e. ACC, power plants of the Tokyo Electric Power Company. The sensor uses laser beams focused on small stainless steel reflectors having bar-code patterns attached on the surface of the rotating shaft, and a technique of signal processing using a correlation function featuring high frequency. The plant that supplied steam was selected on the basis of diagnosis of each steam turbine performance of the plants. Heat balance program was developed to analyze steam turbine performance using data of turbine output measured by the torque sensor and data measured by existing instruments of the power station. The steam turbine that supplied steam was determined by the present method using the optical torque sensor. The accuracy of the method to determine the steam supply plant was analyzed. It was then confirmed that the accuracy was greatly improved as compared with that of existing method.

  3. Revolutionary visible and infrared sensor detectors for the most advanced astronomical AO systems

    NASA Astrophysics Data System (ADS)

    Feautrier, Philippe; Gach, Jean-Luc; Guieu, Sylvain; Downing, Mark; Jorden, Paul; Rothman, Johan; de Borniol, Eric D.; Balard, Philippe; Stadler, Eric; Guillaume, Christian; Boutolleau, David; Coussement, Jérome; Kolb, Johann; Hubin, Norbert; Derelle, Sophie; Robert, Clélia; Tanchon, Julien; Trollier, Thierry; Ravex, Alain; Zins, Gérard; Kern, Pierre; Moulin, Thibaut; Rochat, Sylvain; Delpoulbé, Alain; Lebouqun, Jean-Baptiste

    2014-07-01

    We report in this paper decisive advance on the detector development for the astronomical applications that require very fast operation. Since the CCD220 and OCAM2 major success, new detector developments started in Europe either for visible and IR wavelengths. Funded by ESO and the FP7 Opticon European network, the NGSD CMOS device is fully dedicated to Natural and Laser Guide Star AO for the E-ELT with strong ESO involvement. The NGSD will be a 880x840 pixels CMOS detector with a readout noise of 3 e (goal 1e) at 700 Hz frame rate and providing digital outputs. A camera development, based on this CMOS device and also funded by the Opticon European network, is ongoing. Another major AO wavefront sensing detector development concerns IR detectors based on Avalanche Photodiode (e- APD) arrays within the RAPID project. Developed by the SOFRADIR and CEA/LETI manufacturers, the latter offers a 320x255 8 outputs 30 microns IR array, sensitive from 0.4 to 3 microns, with less than 2 e readout noise at 1600 fps. A rectangular window can also be programmed to speed up even more the frame rate when the full frame readout is not required. The high QE response, in the range of 70%, is almost flat over this wavelength range. Advanced packaging with miniature cryostat using pulse tube cryocoolers was developed in the frame of this programme in order to allow use on this detector in any type of environment. The characterization results of this device are presented here. Readout noise as low as 1.7 e at 1600 fps has been measured with a 3 microns wavelength cut-off chip and a multiplication gain of 14 obtained with a limited photodiode polarization of 8V. This device also exhibits excellent linearity, lower than 1%. The pulse tube cooling allows smart and easy cooling down to 55 K. Vibrations investigations using centroiding and FFT measurements were performed proving that the miniature pulse tube does not induce measurable vibrations to the optical bench, allowing use of this

  4. Electron Pattern Recognition using trigger mode SOI pixel sensor for Advanced Compton Imaging

    NASA Astrophysics Data System (ADS)

    Shimazoe, K.; Yoshihara, Y.; Fairuz, A.; Koyama, A.; Takahashi, H.; Takeda, A.; Tsuru, T.; Arai, Y.

    2016-02-01

    Compton imaging is a useful method for localizing sub MeV to a few MeV gamma-rays and widely used for environmental and medical applications. The direction of recoiled electrons in Compton scattering process provides the additional information to limit the Compton cones and increases the sensitivity in the system. The capability of recoiled electron tracking using trigger-mode Silicon-On-Insulator (SOI) sensor is investigated with various radiation sources. The trigger-mode SOI sensor consists of 144 by 144 active pixels with 30 μm cells and the thickness of sensor is 500 μm. The sensor generates the digital output when it is hit by gamma-rays and 25 by 25 pixel pattern of surrounding the triggered pixel is readout to extract the recoiled electron track. The electron track is successfully observed for 60Co and 137Cs sources, which provides useful information for future electron tracking Compton camera.

  5. CATSI EDM: recent advances in the development and validation of a ruggedized passive standoff CWA sensor

    NASA Astrophysics Data System (ADS)

    Lavoie, Hugo; Thériault, Jean-Marc; Bouffard, François; Puckrin, Eldon; Turcotte, Caroline S.; Lacasse, Paul

    2008-04-01

    Defence Research and Development Canada (DRDC) - Valcartier is currently developing a ruggedized passive standoff sensor for the detection of chemical warfare agents (CWAs) based on differential Fourier-transform infrared (FTIR) radiometry. This system is referred to as the Compact ATmospheric Sounding Interferometer (CATSI) Engineering Development Model (EDM). The CATSI EDM sensor is based on the use of a double-beam FTIR spectrometer that is optimized for optical subtraction. A description of the customized sensor is given along with a discussion on the detection and identification approaches that have been developed. Preliminary results of validation from a number of laboratory measurements and open-air trials are analyzed to establish the capability of detection and identification of various toxic and non-toxic chemical vapor plumes. These results clearly demonstrate the capability of the passive differential radiometric approach for the standoff detection and identification of chemical vapors at distances up to a few kilometers from the sensor.

  6. Recent Advances in the Design of Electro-Optic Sensors for Minimally Destructive Microwave Field Probing

    PubMed Central

    Lee, Dong-Joon; Kang, No-Weon; Choi, Jun-Ho; Kim, Junyeon; Whitaker, John F.

    2011-01-01

    In this paper we review recent design methodologies for fully dielectric electro-optic sensors that have applications in non-destructive evaluation (NDE) of devices and materials that radiate, guide, or otherwise may be impacted by microwave fields. In many practical NDE situations, fiber-coupled-sensor configurations are preferred due to their advantages over free-space bulk sensors in terms of optical alignment, spatial resolution, and especially, a low degree of field invasiveness. We propose and review five distinct types of fiber-coupled electro-optic sensor probes. The design guidelines for each probe type and their performances in absolute electric-field measurements are compared and summarized. PMID:22346604

  7. Sensors

    NASA Astrophysics Data System (ADS)

    Saito, Masato; Hiep, Ha Minh; Nagatani, Naoki; Tamiya, Eiichi

    With recent advances in nanotechnology, development of nanomaterial bioconjugates is growing exponentially towards eventual translation into biomolecular recognition layers on surfaces. Label-free monitoring of biorecognition events is also key-technology and provides a promising platform, which is simple, cost-effective, and requires no external modification to biomolecules. In this review, we describe the application of nanomaterials, mainly metal nanoparticles, and specific applications of carbon nanotubes (CNTs) based label-free approaches.

  8. A real-time implementation of an advanced sensor failure detection, isolation, and accommodation algorithm

    NASA Technical Reports Server (NTRS)

    Delaat, J. C.; Merrill, W. C.

    1984-01-01

    A sensor failure detection, isolation, and accommodation algorithm was developed which incorporates analytic sensor redundancy through software. This algorithm was implemented in a high level language on a microprocessor based controls computer. Parallel processing and state-of-the-art 16-bit microprocessors are used along with efficient programming practices to achieve real-time operation. Previously announced in STAR as N84-13140

  9. Advanced Liquid-Free, Piezoresistive, SOI-Based Pressure Sensors for Measurements in Harsh Environments.

    PubMed

    Ngo, Ha-Duong; Mukhopadhyay, Biswaijit; Ehrmann, Oswin; Lang, Klaus-Dieter

    2015-01-01

    In this paper we present and discuss two innovative liquid-free SOI sensors for pressure measurements in harsh environments. The sensors are capable of measuring pressures at high temperatures. In both concepts media separation is realized using a steel membrane. The two concepts represent two different strategies for packaging of devices for use in harsh environments and at high temperatures. The first one is a "one-sensor-one-packaging_technology" concept. The second one uses a standard flip-chip bonding technique. The first sensor is a "floating-concept", capable of measuring pressures at temperatures up to 400 °C (constant load) with an accuracy of 0.25% Full Scale Output (FSO). A push rod (mounted onto the steel membrane) transfers the applied pressure directly to the center-boss membrane of the SOI-chip, which is placed on a ceramic carrier. The chip membrane is realized by Deep Reactive Ion Etching (DRIE or Bosch Process). A novel propertied chip housing employing a sliding sensor chip that is fixed during packaging by mechanical preloading via the push rod is used, thereby avoiding chip movement, and ensuring optimal push rod load transmission. The second sensor can be used up to 350 °C. The SOI chips consists of a beam with an integrated centre-boss with was realized using KOH structuring and DRIE. The SOI chip is not "floating" but bonded by using flip-chip technology. The fabricated SOI sensor chip has a bridge resistance of 3250 Ω. The realized sensor chip has a sensitivity of 18 mV/µm measured using a bridge current of 1 mA. PMID:26295235

  10. Advanced Liquid-Free, Piezoresistive, SOI-Based Pressure Sensors for Measurements in Harsh Environments

    PubMed Central

    Ngo, Ha-Duong; Mukhopadhyay, Biswaijit; Ehrmann, Oswin; Lang, Klaus-Dieter

    2015-01-01

    In this paper we present and discuss two innovative liquid-free SOI sensors for pressure measurements in harsh environments. The sensors are capable of measuring pressures at high temperatures. In both concepts media separation is realized using a steel membrane. The two concepts represent two different strategies for packaging of devices for use in harsh environments and at high temperatures. The first one is a “one-sensor-one-packaging_technology” concept. The second one uses a standard flip-chip bonding technique. The first sensor is a “floating-concept”, capable of measuring pressures at temperatures up to 400 °C (constant load) with an accuracy of 0.25% Full Scale Output (FSO). A push rod (mounted onto the steel membrane) transfers the applied pressure directly to the center-boss membrane of the SOI-chip, which is placed on a ceramic carrier. The chip membrane is realized by Deep Reactive Ion Etching (DRIE or Bosch Process). A novel propertied chip housing employing a sliding sensor chip that is fixed during packaging by mechanical preloading via the push rod is used, thereby avoiding chip movement, and ensuring optimal push rod load transmission. The second sensor can be used up to 350 °C. The SOI chips consists of a beam with an integrated centre-boss with was realized using KOH structuring and DRIE. The SOI chip is not “floating” but bonded by using flip-chip technology. The fabricated SOI sensor chip has a bridge resistance of 3250 Ω. The realized sensor chip has a sensitivity of 18 mV/µm measured using a bridge current of 1 mA. PMID:26295235

  11. Advances in using MRI probes and sensors for in vivo cell tracking as applied to regenerative medicine

    PubMed Central

    Srivastava, Amit K.; Kadayakkara, Deepak K.; Bar-Shir, Amnon; Gilad, Assaf A.; McMahon, Michael T.; Bulte, Jeff W. M.

    2015-01-01

    The field of molecular and cellular imaging allows molecules and cells to be visualized in vivo non-invasively. It has uses not only as a research tool but in clinical settings as well, for example in monitoring cell-based regenerative therapies, in which cells are transplanted to replace degenerating or damaged tissues, or to restore a physiological function. The success of such cell-based therapies depends on several critical issues, including the route and accuracy of cell transplantation, the fate of cells after transplantation, and the interaction of engrafted cells with the host microenvironment. To assess these issues, it is necessary to monitor transplanted cells non-invasively in real-time. Magnetic resonance imaging (MRI) is a tool uniquely suited to this task, given its ability to image deep inside tissue with high temporal resolution and sensitivity. Extraordinary efforts have recently been made to improve cellular MRI as applied to regenerative medicine, by developing more advanced contrast agents for use as probes and sensors. These advances enable the non-invasive monitoring of cell fate and, more recently, that of the different cellular functions of living cells, such as their enzymatic activity and gene expression, as well as their time point of cell death. We present here a review of recent advancements in the development of these probes and sensors, and of their functioning, applications and limitations. PMID:26035841

  12. Advances in using MRI probes and sensors for in vivo cell tracking as applied to regenerative medicine.

    PubMed

    Srivastava, Amit K; Kadayakkara, Deepak K; Bar-Shir, Amnon; Gilad, Assaf A; McMahon, Michael T; Bulte, Jeff W M

    2015-04-01

    The field of molecular and cellular imaging allows molecules and cells to be visualized in vivo non-invasively. It has uses not only as a research tool but in clinical settings as well, for example in monitoring cell-based regenerative therapies, in which cells are transplanted to replace degenerating or damaged tissues, or to restore a physiological function. The success of such cell-based therapies depends on several critical issues, including the route and accuracy of cell transplantation, the fate of cells after transplantation, and the interaction of engrafted cells with the host microenvironment. To assess these issues, it is necessary to monitor transplanted cells non-invasively in real-time. Magnetic resonance imaging (MRI) is a tool uniquely suited to this task, given its ability to image deep inside tissue with high temporal resolution and sensitivity. Extraordinary efforts have recently been made to improve cellular MRI as applied to regenerative medicine, by developing more advanced contrast agents for use as probes and sensors. These advances enable the non-invasive monitoring of cell fate and, more recently, that of the different cellular functions of living cells, such as their enzymatic activity and gene expression, as well as their time point of cell death. We present here a review of recent advancements in the development of these probes and sensors, and of their functioning, applications and limitations. PMID:26035841

  13. Spatial and temporal structure within moisture measurements of a stormwater control system

    EPA Science Inventory

    Moisture sensing is a mature soil research technology commonly applied to agriculture. Such sensors may be appropriated for use in novel stormwater research applications. Knowledge of moisture (with respect to space and time) in infiltration based stormwater control measures (SCM...

  14. Use of an Autonomous Sensor to Evaluate the Biological Performance of the Advanced Turbine at Wanapum Dam

    SciTech Connect

    Deng, Zhiqun; Carlson, Thomas J.; Duncan, Joanne P.; Richmond, Marshall C.; Dauble, Dennis D.

    2010-10-13

    Hydropower is the largest renewable energy resource in the world and the United States. However, Hydropower dams have adverse ecological impacts because migrating fish may be injured or killed when they pass through hydro turbines. In the Columbia and Snake River basins, dam operators and engineers are required to make these hydroelectric facilities more fish-friendly through changes in hydro-turbine design and operation after fish population declines and the subsequent listing of several species of Pacific salmon in the Endangered Species Act of 1973. Grant County Public Utility District (Grant PUD) requested authorization from the Federal Energy Regulatory Commission to replace the 10 turbines at Wanapum Dam with advanced hydropower turbines that are designed to improve survival for fish passing through the turbines while improving operation efficiency and increasing power generation. The U.S. Department of Energy Office of Energy Efficiency and Renewable Energy provided co-funding to Grant PUD for aspects of performance testing that supported the application. As an additional measure to the primary evaluation measure of direct injury and mortality rates of juvenile Chinook salmon using balloon tag-recapture methodology, this study used an autonomous sensor device to provide insight into the specific hydraulic conditions or physical stresses that the fish experienced or the specific causes of the biological response. We found that the new blade shape and the corresponding reduction of turbulence in the advanced hydropower turbine were effective. The frequency of severe events based on Sensor Fish pressure and acceleration measurements showed trends similar to those of fish survival determined by balloon tag-recapture tests. In addition, the new turbine provided a better pressure and rate of change environment for fish passage. Overall, the Sensor Fish data indicated that the advanced hydro turbine design met the desired fish passage goals for Wanapum Dam.

  15. EDITORIAL: Humidity sensors Humidity sensors

    NASA Astrophysics Data System (ADS)

    Regtien, Paul P. L.

    2012-01-01

    produced at relatively low cost. Therefore, they find wide use in lots of applications. However, the method requires a material that possesses some conflicting properties: stable and reproducible relations between air humidity, moisture uptake and a specific property (for instance the length of a hair, the electrical impedance of the material), fast absorption and desorption of the water vapour (to obtain a short response time), small hysteresis, wide range of relative humidity (RH) and temperature-independent output (only responsive to RH). For these reasons, much research is done and is still going on to find suitable materials that combine high performance and low price. In this special feature, three of the four papers report on absorption sensors, all with different focus. Aziz et al describe experiments with newly developed materials. The surface structure is extensively studied, in view of its ability to rapidly absorb water vapour and exhibit a reproducible change in the resistance and capacitance of the device. Sanchez et al employ optical fibres coated with a thin moisture-absorbing layer as a sensitive humidity sensor. They have studied various coating materials and investigated the possibility of using changes in optical properties of the fibre (here the lossy mode resonance) due to a change in humidity of the surrounding air. The third paper, by Weremczuk et al, focuses on a cheap fabrication method for absorption-based humidity sensors. The inkjet technology appears to be suitable for mass fabrication of such sensors, which is demonstrated by extensive measurements of the electrical properties (resistance and capacitance) of the absorbing layers. Moreover, they have developed a model that describes the relation between humidity and the electrical parameters of the moisture-sensitive layer. Despite intensive research, absorption sensors still do not meet the requirements for high accuracy applications. The dew-point temperature method is more appropriate

  16. Application of Cosmic-ray Soil Moisture Sensing to Understand Land-atmosphere Interactions in Three North American Monsoon Ecosystems

    NASA Astrophysics Data System (ADS)

    Schreiner-McGraw, A.; Vivoni, E. R.; Franz, T. E.; Anderson, C.

    2013-12-01

    Human impacts on desert ecosystems have wide ranging effects on the hydrologic cycle which, in turn, influence interactions between the critical zone and the atmosphere. In this contribution, we utilize cosmic-ray soil moisture sensors at three human-modified semiarid ecosystems in the North American monsoon region: a buffelgrass pasture in Sonora, Mexico, a woody-plant encroached savanna ecosystem in Arizona, and a woody-plant encroached shrubland ecosystem in New Mexico. In each case, landscape heterogeneity in the form of bare soil and vegetation patches of different types leads to a complex mosaic of soil moisture and land-atmosphere interactions. Historically, the measurement of spatially-averaged soil moisture at the ecosystem scale (on the order of several hundred square meters) has been problematic. Thus, new advances in measuring cosmogenically-produced neutrons present an opportunity for observational and modeling studies in these ecosystems. We discuss the calibration of the cosmic-ray soil moisture sensors at each site, present comparisons to a distributed network of in-situ measurements, and verify the spatially-aggregated observations using the watershed water balance method at two sites. We focus our efforts on the summer season 2013 and its rainfall period during the North American monsoon. To compare neutron counts to the ground sensors, we utilized an aspect-elevation weighting algorithm to compute an appropriate spatial average for the in-situ measurements. Similarly, the water balance approach utilizes precipitation, runoff, and evapotranspiration measurements in the footprint of the cosmic-ray sensors to estimate a spatially-averaged soil moisture field. Based on these complementary approaches, we empirically determined a relationship between cosmogenically-produced neutrons and the spatially-aggregated soil moisture. This approach may improve upon existing methods used to calculate soil moisture from neutron counts that typically suffer from

  17. Ultrasonic and LIDAR sensors for electronic canopy characterization in vineyards: advances to improve pesticide application methods.

    PubMed

    Llorens, Jordi; Gil, Emilio; Llop, Jordi; Escolà, Alexandre

    2011-01-01

    Canopy characterization is a key factor to improve pesticide application methods in tree crops and vineyards. Development of quick, easy and efficient methods to determine the fundamental parameters used to characterize canopy structure is thus an important need. In this research the use of ultrasonic and LIDAR sensors have been compared with the traditional manual and destructive canopy measurement procedure. For both methods the values of key parameters such as crop height, crop width, crop volume or leaf area have been compared. Obtained results indicate that an ultrasonic sensor is an appropriate tool to determine the average canopy characteristics, while a LIDAR sensor provides more accuracy and detailed information about the canopy. Good correlations have been obtained between crop volume (C(VU)) values measured with ultrasonic sensors and leaf area index, LAI (R(2) = 0.51). A good correlation has also been obtained between the canopy volume measured with ultrasonic and LIDAR sensors (R(2) = 0.52). Laser measurements of crop height (C(HL)) allow one to accurately predict the canopy volume. The proposed new technologies seems very appropriate as complementary tools to improve the efficiency of pesticide applications, although further improvements are still needed. PMID:22319405

  18. Advances in SXFA-Coated SAW Chemical Sensors for Organophosphorous Compound Detection

    PubMed Central

    Wang, Wen; He, Shitang; Li, Shunzhou; Liu, Minghua; Pan, Yong

    2011-01-01

    A polymer-coated surface acoustic wave (SAW)-based chemical sensor for organophosphorous compound sensing at extremely low concentrations was developed, in which a dual-delay-line oscillator coated with fluoroalcoholpolysiloxane (SXFA) acted as the sensor element. Response mechanism analysis was performed on the SXFA-coated chemical sensor, resulting in the optimal design parameters. The shear modulus of the SXFA, which is the key parameter for theoretical simulation, was extracted experimentally. New designs were done on the SAW devices to decrease the insertion loss. Referring to the new phase modulation approach, superior short-term frequency stability (±2 Hz in seconds) was achieved from the SAW oscillator using the fabricated 300 MHz delay line as the feedback element. In the sensor experiment on dimethylmethylphosphonate (DMMP) detection, the fabricated SXFA-coated chemical sensor exhibited an excellent threshold detection limit up to 0.004 mg/m3 (0.7 ppb) and good sensitivity (∼485 Hz/mg/m3 for a DMMP concentration of 2∼14 mg/m3). PMID:22319366

  19. Emerging tools for continuous nutrient monitoring networks: Sensors advancing science and water resources protection

    USGS Publications Warehouse

    Pellerin, Brian; Stauffer, Beth A; Young, Dwane A; Sullivan, Daniel J.; Bricker, Suzanne B.; Walbridge, Mark R; Clyde, Gerard A; Shaw, Denice M

    2016-01-01

    Sensors and enabling technologies are becoming increasingly important tools for water quality monitoring and associated water resource management decisions. In particular, nutrient sensors are of interest because of the well-known adverse effects of nutrient enrichment on coastal hypoxia, harmful algal blooms, and impacts to human health. Accurate and timely information on nutrient concentrations and loads is integral to strategies designed to minimize risk to humans and manage the underlying drivers of water quality impairment. Using nitrate sensors as an example, we highlight the types of applications in freshwater and coastal environments that are likely to benefit from continuous, real-time nutrient data. The concurrent emergence of new tools to integrate, manage and share large data sets is critical to the successful use of nutrient sensors and has made it possible for the field of continuous nutrient monitoring to rapidly move forward. We highlight several near-term opportunities for Federal agencies, as well as the broader scientific and management community, that will help accelerate sensor development, build and leverage sites within a national network, and develop open data standards and data management protocols that are key to realizing the benefits of a large-scale, integrated monitoring network. Investing in these opportunities will provide new information to guide management and policies designed to protect and restore our nation’s water resources.

  20. Tailored magnetoelastic sensor geometry for advanced functionality in wireless biliary stent monitoring systems

    NASA Astrophysics Data System (ADS)

    Green, Scott R.; Gianchandani, Yogesh B.

    2010-07-01

    This paper presents three types of wireless magnetoelastic resonant sensors with specific functionalities for monitoring sludge accumulation within biliary stents. The first design uses a geometry with a repeated cell shape that provides two well-separated resonant mode shapes and associated frequencies to permit spatial localization of mass loading. The second design implements a pattern with specific variation in feature densities to improve sensitivity to mass loading. The third design uses narrow ribbons joined by flexible couplers; this design adopts the advantages in flexibility and expandability of the other designs while maintaining the robust longitudinal mode shapes of a ribbon-shaped sensor. The sensors are batch patterned using photochemical machining from 25 µm thick 2605SA1 Metglas™, an amorphous Fe-Si alloy. Accumulation of biliary sludge is simulated with paraffin or gelatin, and the effects of viscous bile are simulated with a range of silicone fluids. Results from the first design show that the location of mass loads can be resolved within ~5 mm along the length of the sensor. The second design offers twice the sensitivity to mass loads (3000-36 000 ppm mg-1) of other designs. The third design provides a wide range of loading (sensitive to at least 10× the mass of the sensor) and survives compression into a 2 mm diameter tube as would be required for catheter-based delivery.

  1. Ultrasonic and LIDAR Sensors for Electronic Canopy Characterization in Vineyards: Advances to Improve Pesticide Application Methods

    PubMed Central

    Llorens, Jordi; Gil, Emilio; Llop, Jordi; Escolà, Alexandre

    2011-01-01

    Canopy characterization is a key factor to improve pesticide application methods in tree crops and vineyards. Development of quick, easy and efficient methods to determine the fundamental parameters used to characterize canopy structure is thus an important need. In this research the use of ultrasonic and LIDAR sensors have been compared with the traditional manual and destructive canopy measurement procedure. For both methods the values of key parameters such as crop height, crop width, crop volume or leaf area have been compared. Obtained results indicate that an ultrasonic sensor is an appropriate tool to determine the average canopy characteristics, while a LIDAR sensor provides more accuracy and detailed information about the canopy. Good correlations have been obtained between crop volume (CVU) values measured with ultrasonic sensors and leaf area index, LAI (R2 = 0.51). A good correlation has also been obtained between the canopy volume measured with ultrasonic and LIDAR sensors (R2 = 0.52). Laser measurements of crop height (CHL) allow one to accurately predict the canopy volume. The proposed new technologies seems very appropriate as complementary tools to improve the efficiency of pesticide applications, although further improvements are still needed. PMID:22319405

  2. Advances in SAW Gas Sensors Based on the Condensate-Adsorption Effect

    PubMed Central

    Liu, Jiuling; Wang, Wen; Li, Shunzhou; Liu, Minghua; He, Shitang

    2011-01-01

    A surface-acoustic-wave (SAW) gas sensor with a low detection limit and fast response for volatile organic compounds (VOCs) based on the condensate-adsorption effect detection is developed. In this sensor a gas chromatography (GC) column acts as the separator element and a dual-resonator oscillator acts as the detector element. Regarding the surface effective permittivity method, the response mechanism analysis, which relates the condensate-adsorption effect, is performed, leading to the sensor performance prediction prior to fabrication. New designs of SAW resonators, which act as feedback of the oscillator, are devised in order to decrease the insertion loss and to achieve single-mode control, resulting in superior frequency stability of the oscillator. Based on the new phase modulation approach, excellent short-term frequency stability (±3 Hz/s) is achieved with the SAW oscillator by using the 500 MHz dual-port resonator as feedback element. In a sensor experiment investigating formaldehyde detection, the implemented SAW gas sensor exhibits an excellent threshold detection limit as low as 0.38 pg. PMID:22247697

  3. Recent Advances in Gas and Chemical Detection by Vernier Effect-Based Photonic Sensors

    PubMed Central

    La Notte, Mario; Troia, Benedetto; Muciaccia, Tommaso; Campanella, Carlo Edoardo; De Leonardis, Francesco; Passaro, Vittorio M. N.

    2014-01-01

    Recently, the Vernier effect has been proved to be very efficient for significantly improving the sensitivity and the limit of detection (LOD) of chemical, biochemical and gas photonic sensors. In this paper a review of compact and efficient photonic sensors based on the Vernier effect is presented. The most relevant results of several theoretical and experimental works are reported, and the theoretical model of the typical Vernier effect-based sensor is discussed as well. In particular, sensitivity up to 460 μm/RIU has been experimentally reported, while ultra-high sensitivity of 2,500 μm/RIU and ultra-low LOD of 8.79 × 10−8 RIU have been theoretically demonstrated, employing a Mach-Zehnder Interferometer (MZI) as sensing device instead of an add drop ring resonator. PMID:24618728

  4. Advanced data visualization and sensor fusion: Conversion of techniques from medical imaging to Earth science

    NASA Technical Reports Server (NTRS)

    Savage, Richard C.; Chen, Chin-Tu; Pelizzari, Charles; Ramanathan, Veerabhadran

    1992-01-01

    Hughes Aircraft Company and the University of Chicago propose to transfer existing medical imaging registration algorithms to the area of multi-sensor data fusion. The University of Chicago's algorithms have been successfully demonstrated to provide pixel by pixel comparison capability for medical sensors with different characteristics. The research will attempt to fuse GOES, AVHRR, and SSM/I sensor data which will benefit a wide range of researchers. The algorithms will utilize data visualization and algorithm development tools created by Hughes in its EOSDIS prototyping. This will maximize the work on the fusion algorithms since support software (e.g. input/output routines) will already exist. The research will produce a portable software library with documentation for use by other researchers.

  5. Recent advances in gas and chemical detection by Vernier effect-based photonic sensors.

    PubMed

    La Notte, Mario; Troia, Benedetto; Muciaccia, Tommaso; Campanella, Carlo Edoardo; De Leonardis, Francesco; Passaro, Vittorio M N

    2014-01-01

    Recently, the Vernier effect has been proved to be very efficient for significantly improving the sensitivity and the limit of detection (LOD) of chemical, biochemical and gas photonic sensors. In this paper a review of compact and efficient photonic sensors based on the Vernier effect is presented. The most relevant results of several theoretical and experimental works are reported, and the theoretical model of the typical Vernier effect-based sensor is discussed as well. In particular, sensitivity up to 460 μm/RIU has been experimentally reported, while ultra-high sensitivity of 2,500 μm/RIU and ultra-low LOD of 8.79 × 10(-8) RIU have been theoretically demonstrated, employing a Mach-Zehnder Interferometer (MZI) as sensing device instead of an add drop ring resonator. PMID:24618728

  6. Technology advancement of the CCD201-20 EMCCD for the WFIRST coronagraph instrument: sensor characterization and radiation damage

    NASA Astrophysics Data System (ADS)

    Harding, Leon K.; Demers, Richard T.; Hoenk, Michael; Peddada, Pavani; Nemati, Bijan; Cherng, Michael; Michaels, Darren; Neat, Leo S.; Loc, Anthony; Bush, Nathan; Hall, David; Murray, Neil; Gow, Jason; Burgon, Ross; Holland, Andrew; Reinheimer, Alice; Jorden, Paul R.; Jordan, Douglas

    2016-01-01

    The Wide Field InfraRed Survey Telescope-Astrophysics Focused Telescope Asset (WFIRST-AFTA) mission is a 2.4-m class space telescope that will be used across a swath of astrophysical research domains. JPL will provide a high-contrast imaging coronagraph instrument-one of two major astronomical instruments. In order to achieve the low noise performance required to detect planets under extremely low flux conditions, the electron multiplying charge-coupled device (EMCCD) has been baselined for both of the coronagraph's sensors-the imaging camera and integral field spectrograph. JPL has established an EMCCD test laboratory in order to advance EMCCD maturity to technology readiness level-6. This plan incorporates full sensor characterization, including read noise, dark current, and clock-induced charge. In addition, by considering the unique challenges of the WFIRST space environment, degradation to the sensor's charge transfer efficiency will be assessed, as a result of damage from high-energy particles such as protons, electrons, and cosmic rays. Science-grade CCD201-20 EMCCDs have been irradiated to a proton fluence that reflects the projected WFIRST orbit. Performance degradation due to radiation displacement damage is reported, which is the first such study for a CCD201-20 that replicates the WFIRST conditions. In addition, techniques intended to identify and mitigate radiation-induced electron trapping, such as trap pumping, custom clocking, and thermal cycling, are discussed.

  7. Recent CESAR (Center for Engineering Systems Advanced Research) research activities in sensor based reasoning for autonomous machines

    SciTech Connect

    Pin, F.G.; de Saussure, G.; Spelt, P.F.; Killough, S.M.; Weisbin, C.R.

    1988-01-01

    This paper describes recent research activities at the Center for Engineering Systems Advanced Research (CESAR) in the area of sensor based reasoning, with emphasis being given to their application and implementation on our HERMIES-IIB autonomous mobile vehicle. These activities, including navigation and exploration in a-priori unknown and dynamic environments, goal recognition, vision-guided manipulation and sensor-driven machine learning, are discussed within the framework of a scenario in which an autonomous robot is asked to navigate through an unknown dynamic environment, explore, find and dock at the panel, read and understand the status of the panel's meters and dials, learn the functioning of a process control panel, and successfully manipulate the control devices of the panel to solve a maintenance emergency problems. A demonstration of the successful implementation of the algorithms on our HERMIES-IIB autonomous robot for resolution of this scenario is presented. Conclusions are drawn concerning the applicability of the methodologies to more general classes of problems and implications for future work on sensor-driven reasoning for autonomous robots are discussed. 8 refs., 3 figs.

  8. The SoilSCAPE Network Multiscale In-situ Soil Moisture Measurements: Innovations in Network Design and Approaches to Upscaling in Support of SMAP

    NASA Astrophysics Data System (ADS)

    Moghaddam, M.; Clewley, D.; Silva, A.; Akbar, R.

    2014-12-01

    The Soil Moisture Active Passive (SMAP) mission will provide soil moisture at 3, 9, and 36 km scales through the use of radar and radiometer data. To validate SMAP products, in-situ sensors are required. Typically, validation plans consist of several sensors installed nearly uniformly in the scene. To upscale the soil moisture estimates to the scales of SMAP products requires a large number of sensors, distributed throughout the instrument footprint. Even for the higher resolution SMAP products (3 km) there are often insufficient sensors available within a resolution cell. The Soil moisture Sensing Controller and oPtimal Estimator (SoilSCAPE) project provides a new adaptive validation strategy, including upscaled estimates of soil moisture. By utilizing smarter network technology and optimized sensor placement, more representative measurements of soil moisture are obtained, at a range of spatial scales with lower costs than traditional networks. A large network was established around the Tonzi Ranch site in central California. The network design comprises multiple sites, each with a 10-30 node cluster taking measurements from up to 4 sensors installed at different depths. The nodes wirelessly communicate to a Local Coordinator, which collects data and transmits to a server (http://soilscape.usc.edu). Each node can communicate with the Coordinator up to a distance of 400m. Each station supports up to 60 nodes. Currently 111 nodes have been installed over 6 sites. The SoilSCAPE nonuniform placement of sensors requires novel upscaling methods. Previous studies have used regression, which works well when the measurement is well correlated with other variables. However, soil moisture dependence on various variables could be complex and nonlinear. To account for such complexities, we use the Random Forests algorithm, which is capable of modeling complex non-linear system and can handle continuous and categorical data. The algorithm has not previously been applied to

  9. Improving runoff prediction through the assimilation of the ASCAT soil moisture product

    NASA Astrophysics Data System (ADS)

    Brocca, L.; Melone, F.; Moramarco, T.; Wagner, W.; Naeimi, V.; Bartalis, Z.; Hasenauer, S.

    2010-10-01

    The role and the importance of soil moisture for meteorological, agricultural and hydrological applications is widely known. Remote sensing offers the unique capability to monitor soil moisture over large areas (catchment scale) with, nowadays, a temporal resolution suitable for hydrological purposes. However, the accuracy of the remotely sensed soil moisture estimates has to be carefully checked. The validation of these estimates with in-situ measurements is not straightforward due the well-known problems related to the spatial mismatch and the measurement accuracy. The analysis of the effects deriving from assimilating remotely sensed soil moisture data into hydrological or meteorological models could represent a more valuable method to test their reliability. In particular, the assimilation of satellite-derived soil moisture estimates into rainfall-runoff models at different scales and over different regions represents an important scientific and operational issue. In this study, the soil wetness index (SWI) product derived from the Advanced SCATterometer (ASCAT) sensor onboard of the Metop satellite was tested. The SWI was firstly compared with the soil moisture temporal pattern derived from a continuous rainfall-runoff model (MISDc) to assess its relationship with modeled data. Then, by using a simple data assimilation technique, the linearly rescaled SWI that matches the range of variability of modelled data (denoted as SWI*) was assimilated into MISDc and the model performance on flood estimation was analyzed. Moreover, three synthetic experiments considering errors on rainfall, model parameters and initial soil wetness conditions were carried out. These experiments allowed to further investigate the SWI potential when uncertain conditions take place. The most significant flood events, which occurred in the period 2000-2009 on five subcatchments of the Upper Tiber River in central Italy, ranging in extension between 100 and 650 km2, were used as case studies

  10. Improving runoff prediction through the assimilation of the ASCAT soil moisture product

    NASA Astrophysics Data System (ADS)

    Brocca, L.; Melone, F.; Moramarco, T.; Wagner, W.; Naeimi, V.; Bartalis, Z.; Hasenauer, S.

    2010-07-01

    The role and the importance of soil moisture for meteorological, agricultural and hydrological applications is widely known. Remote sensing offers the unique capability to monitor soil moisture over large areas (catchment scale) with, nowadays, a temporal resolution suitable for hydrological purposes. However, the accuracy of the remotely sensed soil moisture estimates has to be carefully checked. The validation of these estimates with in-situ measurements is not straightforward due the well-known problems related to the spatial mismatch and the measurement accuracy. The analysis of the effects deriving from assimilating remotely sensed soil moisture data into hydrological or meteorological models could represent a more valuable method to test their reliability. In particular, the assimilation of satellite-derived soil moisture estimates into rainfall-runoff models at different scales and over different regions represents an important scientific and operational issue. In this study, the soil wetness index (SWI) product derived from the Advanced SCATterometer (ASCAT) sensor onboard of the Metop satellite was tested. The SWI was firstly compared with the soil moisture temporal pattern derived from a continuous rainfall-runoff model (MISDc) to assess its relationship with modeled data. Then, by using a simple data assimilation technique, the linearly rescaled SWI that matches the range of variability of modelled data (denoted as SWI*) was assimilated into MISDc and the model performance on flood estimation was analyzed. Moreover, three synthetic experiments considering errors on rainfall, model parameters and initial soil wetness conditions were carried out. These experiments allowed to further investigate the SWI potential when uncertain conditions take place. The most significant flood events, which occurred in the period 2000-2009 on five subcatchments of the Upper Tiber River in Central Italy, ranging in extension between 100 and 650 km2, were used as case studies

  11. Recent advances in long-term climate and moisture reconstructions from the Baltic region: Exploring the potential for a new multi-millennial tree-ring chronology

    NASA Astrophysics Data System (ADS)

    Edvardsson, Johannes; Corona, Christophe; Mažeika, Jonas; Pukienė, Rutile; Stoffel, Markus

    2016-01-01

    This study presents the first results from an ongoing initiative to develop a multi-millennial Baltic tree-ring width (TRW) chronology consisting of 12 floating records from subfossil Scots pines (Pinus sylvestris L.) extracted from three Lithuanian peat-mining areas. The floating series have been complemented with absolutely dated TRW chronologies which were obtained from living trees growing in unmanaged and unexploited peatland areas adjacent to each of the above study sites. The subfossil material has been dated by radiocarbon and shows a temporal spread over the last 6000 years, with assemblages of trees during the Holocene Thermal Maximum (HTM; 8000-4000 BP) and the onset of the Medieval Warm Period (MWP, AD 900-1350). Annual tree growth and sample replication of peatland pines reflect moisture variations and long-term climate variability. The importance of extending the TRW chronologies should not therefore be underestimated as (1) climate records of comparable length and resolution do not exist for the Baltic region, but also as (2) a result of a widespread lack of detailed moisture proxies spanning several millennia. Our data clearly show that a 6000-yr, continuous pine chronology from the Baltic region is a realistic objective, and would doubtlessly fill a major geographic gap in an ecologically sensitive region located at the interface between the temperate and boreal vegetation zones.

  12. Soil water sensors:Problems, advances and potential for irrigation scheduling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irrigation water management has to do with the appropriate application of water to soils, in terms of amounts, rates, and timing to satisfy crop water demands, while protecting the soil and water resources from degradation. In this regard, sensors can be used to monitor the soil water status; and so...

  13. Initial assessments of life support technology evolution and advanced sensor requirements, volume 2, appendix A

    NASA Technical Reports Server (NTRS)

    Montgomery, Edward E.

    1991-01-01

    The primary issues studied were how the transition from a physical/chemical (P/C) to hybrid to a Closed Ecological Life Support System (CELSS) could be achieved, what sensors and monitors are needed for a P/C -CELSS hybrid system, and how a CELSS could be automated and what controls would be needed to do so.

  14. Ultra sensitive magnetic sensors integrating the giant magnetoelectric effect with advanced microelectronics

    NASA Astrophysics Data System (ADS)

    Fang, Zhao

    This dissertation investigates approaches to enhance the performance, especially the sensitivity and signal to noise ratio of magnetoelectric sensors, which exploits the magnetoelectric coupling in magnetostrictive and piezoelectric laminate composites. A magnetic sensor is a system or device that can measure the magnitude of a magnetic field or each of its vector components. Usually the techniques encompass many aspects of physics and electronics. The common technologies used for magnetic field sensing include induction coil sensors, fluxgate, SQUID (superconducting quantum interference device), Hall effect, giant magnetoresistance, magnetostrictive/piezoelectric composites, and MEMS (microelectromechanical systems)-based magnetic sensors. Magnetic sensors have found a broad range of applications for many decades. For example, ultra sensitive magnetic sensors are able to detect tiny magnetic fields produced outside the brain by the neuronal currents which can be used for diagnostic application. Measuring the brain's magnetic field is extremely challenging because they are so weak, have strengths of 0.1--1 pT and thus requiring magnetic sensors with sub-picotesla sensitivity. In fact, to date, these measurements can only performed with the most sensitive magnetic sensors, i.e., SQUID. However, such detectors need expensive and cumbersome cryogenics to operate. Additionally, the thermal insulation of the sensors prevents them from being placed very closed to the tissues under study, thereby preventing high-resolution measurement capability. All of these severely limit their broad usage and proliferation for biomedical imaging, diagnosis, and research. A novel ultra-sensitive magnetic sensor capable of operating at room temperature is investigated in this thesis. Magnetoelectric effect is a material phenomenon featuring the interchange between the magnetic and electric energies or signals. The large ME effect observed in ME composites, especially the ME laminates

  15. Advanced multispectral sensor requirements for remote sensing of agriculture and land cover

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Modern agricultural and land cover monitoring programs require frequent data acquisitions and increased spectral resolution to acquire a greater number of parameters in a more accurate manner. Whereas hyperspectral sensors could provide the required information, agriculture's biggest need is for fr...

  16. On-line sensor monitoring for chemical contaminant attenuation during UV/H2O2 advanced oxidation process.

    PubMed

    Yu, Hye-Weon; Anumol, Tarun; Park, Minkyu; Pepper, Ian; Scheideler, Jens; Snyder, Shane A

    2015-09-15

    A combination of surrogate parameters and indicator compounds were measured to predict the removal efficiency of trace organic compounds (TOrCs) using low pressure (LP)-UV/H2O2 advanced oxidation process (AOP), engaged with online sensor-based monitoring system. Thirty-nine TOrCs were evaluated in two distinct secondary wastewater effluents in terms of estimated photochemical reactivity, as a function of the rate constants of UV direct photolysis (kUV) and hydroxyl radical (OH) oxidation (kOH). The selected eighteen TOrCs were classified into three groups that served as indicator compounds: Group 1 for photo-susceptible TOrCs but with minor degradation by OH oxidation (diclofenac, fluoxetine, iohexol, iopamidol, iopromide, simazine and sulfamethoxazole); Group 2 for TOrCs susceptible to both direct photolysis and OH oxidation (benzotriazole, diphenhydramine, ibuprofen, naproxen and sucralose); and Group 3 for photo-resistant TOrCs showing dominant degradation by OH oxidation (atenolol, carbamazepine, DEET, gemfibrozil, primidone and trimethoprim). The results indicate that TOC (optical-based measurement), UVA254 or UVT254 (UV absorbance or transmittance at 254 nm), and total fluorescence can all be used as suitable on-line organic surrogate parameters to predict the attenuation of TOrCs. Furthermore, the automated real-time monitoring via on-line surrogate sensors and equipped with the developed degradation profiles between sensor response and a group of TOrCs removal can provide a diagnostic tool for process control during advanced treatment of reclaimed waters. PMID:26074188

  17. Multi-objective calibration of a hydrologic model using spatially distributed remotely sensed/in-situ soil moisture

    NASA Astrophysics Data System (ADS)

    Rajib, Mohammad Adnan; Merwade, Venkatesh; Yu, Zhiqiang

    2016-05-01

    The objective of this study is to evaluate the relative potential of spatially distributed surface and root zone soil moisture estimates in calibration of Soil and Water Assessment Tool (SWAT) toward improving its hydrologic predictability with reduced equifinality. The Upper Wabash and Cedar Creek, two agriculture-dominated watersheds in Indiana, USA are considered as test beds to implement this multi-objective SWAT calibration. The proposed calibration approach is performed using remotely sensed Advanced Microwave Scanning Radiometer-Earth Observing System surface soil moisture (∼1 cm top soil) estimates (NASA's Aqua daily level-3 gridded land surface product-version 2) in sub-basin/HRU level together with observed streamflow data at the watershed's outlet. Although application of remote sensing data in calibration improves surface soil moisture simulation, other hydrologic components such as streamflow, evapotranspiration (ET) and deeper layer moisture content in SWAT remain less affected. An extension of this approach to apply root zone soil moisture estimates from limited field sensor data showed considerable improvement in the simulation of root zone moisture content and streamflow with corresponding observed data. Difference in relative sensitivity of parameters and reduced extent of uncertainty are also evident from the proposed method, especially for parameters related to the subsurface hydrologic processes. Regardless, precise representation of vertical soil moisture stratification at different layers is difficult with current SWAT ET depletion mechanism. While the results from this study show that root zone soil moisture can play a major role in SWAT calibration, more studies including various soil moisture data products are necessary to validate the proposed approach.

  18. Advanced Start of Combustion Sensor Phases I and II-A: Feasibility Demonstration, Design and Optimization

    SciTech Connect

    Chad Smutzer

    2010-01-31

    Homogeneous Compressed Charge Ignition (HCCI) has elevated the need for Start of Combustion (SOC) sensors. HCCI engines have been the exciting focus of engine research recently, primarily because HCCI offers higher thermal efficiency than the conventional Spark Ignition (SI) engines and significantly lower NOx and soot emissions than conventional Compression Ignition (CI) engines, and could be fuel neutral. HCCI has the potential to unify all the internal combustion engine technology to achieve the high-efficiency, low-emission goal. However, these advantages do not come easy. It is well known that the problems encountered with HCCI combustion center on the difficulty of controlling the Start of Combustion. TIAX has an SOC sensor under development which has shown promise. In previous work, including a DOE-sponsored SBIR project, TIAX has developed an accelerometer-based method which was able to determine SOC within a few degrees crank angle for a range of operating conditions. A signal processing protocol allows reconstruction of the combustion pressure event signal imbedded in the background engine vibration recorded by the accelerometer. From this reconstructed pressure trace, an algorithm locates the SOC. This SOC sensor approach is nonintrusive, rugged, and is particularly robust when the pressure event is strong relative to background engine vibration (at medium to high engine load). Phase I of this project refined the previously developed technology with an engine-generic and robust algorithm. The objective of the Phase I research was to answer two fundamental questions: Can the accelerometer-based SOC sensor provide adequate SOC event capture to control an HCCI engine in a feedback loop? And, will the sensor system meet cost, durability, and software efficiency (speed) targets? Based upon the results, the answer to both questions was 'YES'. The objective of Phase II-A was to complete the parameter optimization of the SOC sensor prototype in order to reach a

  19. Synergies of the European Microwave Remote Sensing Missions SMOS and ASCAT for Monitoring Soil Moisture

    NASA Astrophysics Data System (ADS)

    Scipal, K.; Wagner, W.

    2003-04-01

    The lack of global soil moisture observations is one of the most glaring and pressing deficiencies in current research activities of related fields, from climate monitoring and ecological applications to the quantification of biogeophysical fluxes. This has implications for important issues of the international political agenda like managing global water resources, securing food production and studying climate change. Currently it is held that only microwave remote sensing offers the potential to produce reliable global scale soil moisture information economically. Recognising the urgent need for a soil moisture mission several international initiatives are planning satellite missions dedicated to monitor the global hydrological cycle among them two European microwave satellites. ESA is planning to launch the Soil Moisture and Ocean Salinity Mission SMOS, in 2006. SMOS will measure soil moisture over land and ocean salinity over the oceans. The mission rests on a passive microwave sensor (radiometer) operated in L-band which is currently believed to hold the largest potential for soil moisture retrieval. One year before (2005) EUMETSAT will launch the Meteorological Operational satellite METOP which carries the active microwave system Advanced Scatterometer ASCAT on board. ASCAT has been designed to retrieve winds over the oceans but recent research has established its capability to retrieve soil moisture. Although currently it is hold that, using active microwave techniques, the effect of surface roughness dominates that of soil moisture (while the converse is true for radiometers), the ERS scatterometer was successfully used to derive global soil moisture information at a spatial resolution of 50 km with weekly to decadal temporal resolution. The quality of the soil moisture products have been assessed by independent experts in several pilot projects funded by the European Space Agency. There is evidence to believe that both missions will provide a flow of

  20. Advanced Telescopes and Observatories and Scientific Instruments and Sensors Capability Roadmaps: General Background and Introduction

    NASA Technical Reports Server (NTRS)

    Coulter, Dan; Bankston, Perry

    2005-01-01

    Agency objective are: Strategic Planning Transformation. Advanced Planning Organizational Roles. Public Involvement in Strategic Planning. Strategic Roadmaps and Schedule. Capability Roadmaps and Schedule. Purpose of NRC Review. Capability Roadmap Development (Progress to Date).

  1. Overview of advances in water management in agricultural production:Sensor based irrigation management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Technological advances in irrigated agriculture are crucial to meeting the challenge of increasing demand for agricultural products given limited quality and quantity of water resources for irrigation, impacts of climate variability, and the need to reduce environmental impacts. Multidisciplinary ap...

  2. Advanced selective non-invasive ketone body detection sensors based on new ionophores

    NASA Astrophysics Data System (ADS)

    Sathyapalan, A.; Sarswat, P. K.; Zhu, Y.; Free, M. L.

    2014-12-01

    New molecules and methods were examined that can be used to detect trace level ketone bodies. Diseases such as type 1 diabetes, childhood hypo-glycaemia-growth hormone deficiency, toxic inhalation, and body metabolism changes are linked with ketone bodies concentration. Here we introduce, selective ketone body detection sensors based on small, environmentally friendly organic molecules with Lewis acid additives. Density functional theory (DFT) simulation of the sensor molecules (Bromo-acetonaphthone tungstate (BANT) and acetonaphthophenyl ether propiono hydroxyl tungstate (APPHT)), indicated a fully relaxed geometry without symmetry attributes and specific coordination which enhances ketone bodies sensitivity. A portable sensing unit was made in which detection media containing ketone bodies at low concentration and new molecules show color change in visible light as well as unique irradiance during UV illumination. RGB analysis, electrochemical tests, SEM characterization, FTIR, absorbance and emission spectroscopy were also performed in order to validate the ketone sensitivity of these new molecules.

  3. Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications.

    PubMed

    Di Sante, Raffaella

    2015-01-01

    In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS) have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques. PMID:26263987

  4. Recent advances of mid-infrared compact, field deployable sensors: principles and applications

    NASA Astrophysics Data System (ADS)

    Tittel, Frank; Gluszek, Aleksander; Hudzikowski, Arkadiusz; Dong, Lei; Li, Chunguang; Patimisco, Pietro; Sampaolo, Angelo; Spagnolo, Vincenzo; Wojtas, Jacek

    2016-04-01

    The recent development of compact interband cascade lasers(ICLs) and quantum cascade lasers (QCLs) based trace gas sensors will permit the targeting of strong fundamental rotational-vibrational transitions in the mid-infrared which are one to two orders of magnitude more intense than transitions in the overtone and combination bands in the near-infrared. This has led to the design and fabrication of mid-infrared compact, field deployable sensors for use in the petrochemical industry, environmental monitoring and atmospheric chemistry. Specifically, the spectroscopic detection and monitoring of four molecular species, methane (CH4) [1], ethane (C2H6), formaldehyde (H2CO) [2] and hydrogen sulphide (H2S) [3] will be described. CH4, C2H6 and H2CO can be detected using two detection techniques: mid-infrared tunable laser absorption spectroscopy (TDLAS) using a compact multi-pass gas cell and quartz enhanced photoacoustic spectroscopy (QEPAS). Both techniques utilize state-of-the-art mid-IR, continuous wave (CW), distributed feedback (DFB) ICLs and QCLs. TDLAS was performed with an ultra-compact 54.6m effective optical path length innovative spherical multipass gas cell capable of 435 passes between two concave mirrors separated by 12.5 cm. QEPAS used a small robust absorption detection module (ADM) which consists of a quartz tuning fork (QTF), two optical windows, gas inlet/outlet ports and a low noise frequency pre-amplifier. Wavelength modulation and second harmonic detection were employed for spectral data processing. TDLAS and QEPAS can achieve minimum detectable absorption losses in the range from 10-8 to 10-11cm-1/Hz1/2. Several recent examples of real world applications of field deployable gas sensors will be described. For example, an ICL based TDLAS sensor system is capable of detecting CH4 and C2H6 concentration levels of 1 ppb in a 1 sec. sampling time, using an ultra-compact, robust sensor architecture. H2S detection was realized with a THz QEPAS sensor

  5. Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications

    PubMed Central

    Di Sante, Raffaella

    2015-01-01

    In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS) have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques. PMID:26263987

  6. Intelligent Control via Wireless Sensor Networks for Advanced Coal Combustion Systems

    SciTech Connect

    Aman Behal; Sunil Kumar; Goodarz Ahmadi

    2007-08-05

    Numerical Modeling of Solid Gas Flow, System Identification for purposes of modeling and control, and Wireless Sensor and Actor Network design were pursued as part of this project. Time series input-output data was obtained from NETL's Morgantown CFB facility courtesy of Dr. Lawrence Shadle. It was run through a nonlinear kernel estimator and nonparametric models were obtained for the system. Linear and first-order nonlinear kernels were then utilized to obtain a state-space description of the system. Neural networks were trained that performed better at capturing the plant dynamics. It is possible to use these networks to find a plant model and the inversion of this model can be used to control the system. These models allow one to compare with physics based models whose parameters can then be determined by comparing them against the available data based model. On a parallel track, Dr. Kumar designed an energy-efficient and reliable transport protocol for wireless sensor and actor networks, where the sensors could be different types of wireless sensors used in CFB based coal combustion systems and actors are more powerful wireless nodes to set up a communication network while avoiding the data congestion. Dr. Ahmadi's group studied gas solid flow in a duct. It was seen that particle concentration clearly shows a preferential distribution. The particles strongly interact with the turbulence eddies and are concentrated in narrow bands that are evolving with time. It is believed that observed preferential concentration is due to the fact that these particles are flung out of eddies by centrifugal force.

  7. A review of recent advances in optical fibre sensors for in vivo dosimetry during radiotherapy

    PubMed Central

    O'Keeffe, S; McCarthy, D; Woulfe, P; Grattan, M W D; Hounsell, A R; Sporea, D; Mihai, L; Vata, I; Leen, G

    2015-01-01

    This article presents an overview of the recent developments and requirements in radiotherapy dosimetry, with particular emphasis on the development of optical fibre dosemeters for radiotherapy applications, focusing particularly on in vivo applications. Optical fibres offer considerable advantages over conventional techniques for radiotherapy dosimetry, owing to their small size, immunity to electromagnetic interferences, and suitability for remote monitoring and multiplexing. The small dimensions of optical fibre-based dosemeters, together with being lightweight and flexible, mean that they are minimally invasive and thus particularly suited to in vivo dosimetry. This means that the sensor can be placed directly inside a patient, for example, for brachytherapy treatments, the optical fibres could be placed in the tumour itself or into nearby critical tissues requiring monitoring, via the same applicators or needles used for the treatment delivery thereby providing real-time dosimetric information. The article outlines the principal sensor design systems along with some of the main strengths and weaknesses associated with the development of these techniques. The successful demonstration of these sensors in a range of different clinical environments is also presented. PMID:25761212

  8. SMOS Soil Moisture Validation with Dense and Sparse Networks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Validation is an important but particularly challenging task for passive microwave remote sensing of soil moisture from Earth orbit. The key issue is spatial scale; conventional measurements of soil moisture are made at a point whereas satellite sensors provide an integrated area/volume value for a ...

  9. Soil Moisture Algorithm Validation with Ground Based Networks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Validation satellite-based soil moisture algorithms and products is particularly challenging due to the disparity of scales of the two observation methods, conventional measurements of soil moisture are made at a point whereas satellite sensors provide an integrated area/volume value over a large ar...

  10. MEASUREMENT OF BALE MOISTURE CONTENT BASED ON BALE COMPRESSION PRESSURE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Proper control of the moisture content (mc) of ginned lint in commercial gins requires accurate moisture sensors. A microprocessor-based system that predicted the mc of lint in the bale based on the bale press geometry and the hydraulic pressure required to form the bale was installed in a new gin ...

  11. VALIDATION OF SATELLITE-BASED SOIL MOISTURE ALGORITHMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Validation is an important but particularly challenging task for passive microwave remote sensing of soil moisture from Earth orbit. The key issue is spatial scale; conventional measurements of soil moisture are made at a point whereas satellite sensors provide an integrated area/volume value for a ...

  12. Understanding Zinc Quantification with Existing and Advanced Ditopic Fluorescent Zinpyr Sensors

    PubMed Central

    Buccella, Daniela; Horowitz, Joshua A.; Lippard, Stephen J.

    2011-01-01

    Treatment of aqueous zinc solutions with incremental additions of a ditopic fluorescent sensor of the Zinpyr family, based on pyridine/pyrazine-containing metal recognition units, affords a fluorescence titration curve with a sharp maximum at a sensor:Zn2+ ratio of 0.5 (Zhang, X-a.; Hayes, D.; Smith, S. J.; Friedle, S.; Lippard, S. J. J. Am. Chem Soc. 2008, 130, 15788–15789). This fluorescence response enables the quantification of readily chelatable zinc in biological samples by a simple titration protocol. In the present work a new set of ditopic fluorescence zinc sensors functionalized with pyridine/pyrazine-containing metal chelating units is described, and through detailed studies the principles governing the characteristic “OFF-ON-OFF” fluorescence behavior and quantification capabilities of the family are delineated. Incorporation of carboxylate/ester groups in the 6 position of the fluorescein allows for control of the spatial distribution of the sensor for selective extra- or intracellular imaging of mobile zinc, without introducing significant changes in zinc-binding properties. A combination of spectrophotometric and potentiometric measurements provided a complete description of the H+ and Zn2+ binding properties of the compounds and their correlation with the observed fluorescence profile. The first zinc-binding event has an apparent affinity, K1′, of 1.9–3.1×109 M−1, whereas for coordination of the second Zn2+ ion, responsible for fluorescence turn on, the apparent formation constant K2′ is 5.5–6.9×107 M−1. A detailed chemical and mathematical analysis of the system demonstrated that the difference in emission efficiencies of the dimetalated (LZn2) vs. monometalated (LZn) and metal free (L) forms, a consequence of the combined quenching effects of the two metal-chelating units, significantly influences the shape of the titration curve. The scope of the titration method was investigated mathematically, and a lower boundary for the

  13. Understanding zinc quantification with existing and advanced ditopic fluorescent Zinpyr sensors.

    PubMed

    Buccella, Daniela; Horowitz, Joshua A; Lippard, Stephen J

    2011-03-23

    Treatment of aqueous zinc solutions with incremental additions of a ditopic fluorescent sensor of the Zinpyr family, based on pyridine/pyrazine-containing metal recognition units, affords a fluorescence titration curve with a sharp maximum at a sensor:Zn(2+) ratio of 0.5 (Zhang, X-a.; Hayes, D.; Smith, S. J.; Friedle, S.; Lippard, S. J. J. Am. Chem. Soc.2008, 130, 15788-15789). This fluorescence response enables the quantification of readily chelatable zinc in biological samples by a simple titration protocol. In the present work a new set of ditopic fluorescence zinc sensors functionalized with pyridine/pyrazine-containing metal chelating units is described, and through detailed studies the principles governing the characteristic OFF-ON-OFF fluorescence behavior and quantification capabilities of the family are delineated. Incorporation of carboxylate/ester groups in the 6 position of the fluorescein allows for control of the spatial distribution of the sensor for selective extra- or intracellular imaging of mobile zinc, without introducing significant changes in zinc-binding properties. A combination of spectrophotometric and potentiometric measurements provided a complete description of the H(+)- and Zn(2+)-binding properties of the compounds and their correlation with the observed fluorescence profile. The first zinc-binding event has an apparent affinity, K(1)', of 1.9 × 10(9)-3.1 × 10(9) M(-1), whereas for coordination of the second Zn(2+) ion, responsible for fluorescence turn-on, the apparent formation constant, K(2)', is 5.5 × 10(7)-6.9 × 10(7) M(-1). A detailed chemical and mathematical analysis of the system demonstrated that the difference in emission efficiencies of the dimetalated (LZn(2)) vs monometalated (LZn) and metal-free (L) forms, a consequence of the combined quenching effects of the two metal-chelating units, significantly influences the shape of the titration curve. The scope of the titration method was investigated mathematically, and a

  14. Fiber Optic Control System integration for advanced aircraft. Electro-optic and sensor fabrication, integration, and environmental testing for flight control systems

    NASA Technical Reports Server (NTRS)

    Seal, Daniel W.; Weaver, Thomas L.; Kessler, Bradley L.; Bedoya, Carlos A.; Mattes, Robert E.

    1994-01-01

    This report describes the design, development, and testing of passive fiber optic sensors and a multiplexing electro-optic architecture (EOA) for installation and flight test on a NASA-owned F-18 aircraft. This hardware was developed under the Fiber Optic Control Systems for Advanced Aircraft program, part of a multiyear NASA initiative to design, develop, and demonstrate through flight test 'fly-by-light' systems for application to advanced aircraft flight and propulsion control. This development included the design and production of 10 passive optical sensors and associated multiplexed EOA hardware based on wavelength division multiplexed (WDM) technology. A variety of sensor types (rotary position, linear position, temperature, and pressure) incorporating a broad range of sensor technologies (WDM analog, WDM digital, analog microbend, and fluorescent time rate of decay) were obtained from different manufacturers and functionally integrated with an independently designed EOA. The sensors were built for installation in a variety of aircraft locations, placing the sensors in a variety of harsh environments. The sensors and EOA were designed and built to have the resulting devices be as close as practical to a production system. The integrated system was delivered to NASA for flight testing on a NASA-owned F-18 aircraft. Development and integration testing of the system provided valuable information as to which sensor types were simplest to design and build for a military aircraft environment and which types were simplest to operate with a multiplexed EOA. Not all sensor types met the full range of performance and environmental requirements. EOA development problems provided information on directions to pursue in future fly-by-light flight control development programs. Lessons learned in the development of the EOA and sensor hardware are summarized.

  15. Estimating root-zone soil moisture via the simultaneous assimilation of thermal and microwave soil moisture retrievals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The upcoming deployment of satellite-based microwave sensors designed specifically to retrieve surface soil moisture represents an important milestone in efforts to develop hydrologic applications for remote sensing observations. However, the vertical support of microwave-based surface soil moistur...

  16. Passive Microwave Remote Sensing of Soil Moisture

    NASA Technical Reports Server (NTRS)

    Njoku, Eni G.; Entekhabi, Dara

    1996-01-01

    Microwave remote sensing provides a unique capability for direct observation of soil moisture. Remote measurements from space afford the possibility of obtaining frequent, global sampling of soil moisture over a large fraction of the Earth's land surface. Microwave measurements have the benefit of being largely unaffected by cloud cover and variable surface solar illumination, but accurate soil moisture estimates are limited to regions that have either bare soil or low to moderate amounts of vegetation cover. A particular advantage of passive microwave sensors is that in the absence of significant vegetation cover soil moisture is the dominant effect on the received signal. The spatial resolutions of passive Microwave soil moisture sensors currently considered for space operation are in the range 10-20 km. The most useful frequency range for soil moisture sensing is 1-5 GHz. System design considerations include optimum choice of frequencies, polarizations, and scanning configurations, based on trade-offs between requirements for high vegetation penetration capability, freedom from electromagnetic interference, manageable antenna size and complexity, and the requirement that a sufficient number of information channels be available to correct for perturbing geophysical effects. This paper outlines the basic principles of the passive microwave technique for soil moisture sensing, and reviews briefly the status of current retrieval methods. Particularly promising are methods for optimally assimilating passive microwave data into hydrologic models. Further studies are needed to investigate the effects on microwave observations of within-footprint spatial heterogeneity of vegetation cover and subsurface soil characteristics, and to assess the limitations imposed by heterogeneity on the retrievability of large-scale soil moisture information from remote observations.

  17. Uncertainty Analysis And Synergy Of Aerosol Products From Multiple Satellite Sensors For Advanced Atmospheric Research

    NASA Astrophysics Data System (ADS)

    Ichoku, C. M.; Petrenko, M.

    2013-05-01

    Aerosols are tiny particles suspended in the air, and can be made up of wind-blown dust, smoke from fires, and particulate emissions from automobiles, industries, and other natural and man-made sources. Aerosols can have significant impacts on the air quality, and can interact with clouds and solar radiation in such a way as to affect the water cycle and climate. However, the extent and scale of these impacts are still poorly understood, and this represents one of the greatest uncertainties in climate research to date. To fill this gap in our knowledge, the global and local properties of atmospheric aerosols are being extensively observed and measured, especially during the last decade, using both satellite and ground-based instruments, including such spaceborne sensors as MODIS on the Terra and Aqua satellites, MISR on Terra, OMI on Aura, POLDER on PARASOL, CALIOP on CALIPSO, SeaWiFS on SeaStar, and the ground-based Aerosol Robotic Network (AERONET) of sunphotometers. The aerosol measurements collected by these instruments over the last decade contribute to an unprecedented availability of the most complete set of complimentary aerosol measurements ever acquired. Still, to be able to utilize these measurements synergistically, they have to be carefully and uniformly analyzed and inter-compared, in order to understand the uncertainties and limitations of the products - a process that is greatly complicated by the diversity of differences that exist among them. In this presentation, we will show results of a coherent comparative uncertainty analysis of aerosol measurements from the above-named satellite sensors relative to AERONET. We use these results to demonstrate how these sensors perform in different parts of the world over different landcover types as well as their performance relative to one another, thereby facilitating product selection and integration for specific research and applications needs.

  18. Advancing Unmanned Aircraft Sensor Collection and Communication Capabilities with Optical Communications

    NASA Astrophysics Data System (ADS)

    Lukaczyk, T.

    2015-12-01

    Unmanned aircraft systems (UAS) are now being used for monitoring climate change over both land and seas. Their uses include monitoring of cloud conditions and atmospheric composition of chemicals and aerosols due to pollution, dust storms, fires, volcanic activity and air-sea fluxes. Additional studies of carbon flux are important for various ecosystem studies of both marine and terrestrial environments specifically, and can be related to climate change dynamics. Many measurements are becoming more complex as additional sensors become small enough to operate on more widely available small UAS. These include interferometric radars as well as scanning and fan-beam lidar systems which produce data streams even greater than those of high resolution video. These can be used to precisely map surfaces of the earth, ocean or ice features that are important for a variety of earth system studies. As these additional sensor capabilities are added to UAS the ability to transmit data back to ground or ship monitoring sites is limited by traditional wireless communication protocols. We describe results of tests of optical communication systems that provide significantly greater communication bandwidths for UAS, and discuss both the bandwidth and effective range of these systems, as well as their power and weight requirements both for systems on UAS, as well as those of ground-based receiver stations. We justify our additional use of Delay and Disruption Tolerant Networking (DTN) communication protocols with optical communication methods to ensure security and continuity of command and control operations. Finally, we discuss the implications for receiving, geo-referencing, archiving and displaying data streams from sensors communicated via optical communication to better enable real-time anomaly detection and adaptive sampling capabilities using multiple UAS or other unmanned or manned systems.

  19. An advanced AFM sensor for high-aspect ratio pattern profile in-line measurement

    NASA Astrophysics Data System (ADS)

    Watanabe, Masahiro; Baba, Shuichi; Nakata, Toshihiko; Kurenuma, Toru; Kuroda, Hiroshi; Hiroki, Takenori

    2006-03-01

    Design rule shrinkage and the wider adoption of new device structures such as STI, copper damascene interconnects, and deep trench structures have increased the necessity of in-line process monitoring of step heights and profiles of device structures. For monitoring active device patterns, not test patterns as in OCD, AFM is the only non-destructive 3D monitoring tool. The barriers to using AFM in-line monitoring are its slow throughput and the accuracy degradation associated with probe tip wear and spike noise caused by unwanted oscillation on the steep slopes of high-aspect-ratio patterns. Our proprietary AFM scanning method, Step in mode®, is the method best suited to measuring high-aspect-ratio pattern profiles. Because the probe is not dragged on the sample surface as in conventional AFM, the profile trace fidelity across steep slopes is excellent. Because the probe does not oscillate and hit the sample at a high frequency as in AC scanning mode, this mode is free from unwanted spurious noises on steep sample slopes and incurs extremely little probe tip wear. To fully take advantage of the above properties, we have developed an AFM sensor optimized for in-line use, which produces accurate profile data at high speeds. The control scheme we have developed for the AFM sensor, which we call "Smart Step-in", elaborately analyses the contact force signal, enabling efficient probe tip scanning and a low and stable contact force. The mechanism of the AFM sensor has been optimized for the higher scanning rate and has improved the accuracy, such as the scanning planarity, position and height accuracy, and slope angle accuracy. Our prototype AFM sensor can scan high-aspect-ratio patterns while stabilizing the contact force at 3 nN. The step height measurement repeatability was 0.8 nm (3σ). A STI-like test pattern was scanned, and the steep sidewalls with angles of 84° were measured with high fidelity and without spurious noises.

  20. Study of QCL Laser Sources for the Realization of Advanced Sensors

    PubMed Central

    de Risi, Giuseppe; Columbo, Lorenzo Luigi; Brambilla, Massimo

    2015-01-01

    We study the nonlinear dynamics of a quantum cascade laser (QCL) with a strong reinjection provided by the feedback from two external targets in a double cavity configuration. The nonlinear coupling of interferometric signals from the two targets allows us to propose a displacement sensor with nanometric resolution. The system exploits the ultra-stability of QCLs in self-mixing configuration to access the intrinsic nonlinearity of the laser, described by the Lang–Kobayashi model, and it relies on a stroboscopic-like effect in the voltage signal registered at the QCL terminals that relates the “slow” target motion to the “fast” target one. PMID:26251907

  1. Load-cell based characterization system for a "Violin-Mode" shadow-sensor in advanced LIGO suspensions.

    PubMed

    Lockerbie, N A; Tokmakov, K V

    2016-07-01

    The background to this work was a prototype shadow sensor, which was designed for retro-fitting to an advanced LIGO (Laser Interferometer Gravitational wave Observatory) test-mass/mirror suspension, in which 40 kg test-mass/mirrors are each suspended by four approximately 600 mm long by 0.4 mm diameter fused-silica suspension fibres. The shadow sensor comprised a LED source of Near InfraRed (NIR) radiation and a rectangular silicon photodiode detector, which, together, were to bracket the fibre under test. The aim was to detect transverse Violin-Mode resonances in the suspension fibres. Part of the testing procedure involved tensioning a silica fibre sample and translating it transversely through the illuminating NIR beam, so as to measure the DC responsivity of the detection system to fibre displacement. However, an equally important part of the procedure, reported here, was to keep the fibre under test stationary within the beam, whilst trying to detect low-level AC Violin-Mode resonances excited on the fibre, in order to confirm the primary function of the sensor. Therefore, a tensioning system, incorporating a load-cell readout, was built into the test fibre's holder. The fibre then was excited by a signal generator, audio power amplifier, and distant loudspeaker, and clear resonances were detected. A theory for the expected fundamental resonant frequency as a function of fibre tension was developed and is reported here, and this theory was found to match closely with the detected resonant frequencies as they varied with tension. Consequently, the resonances seen were identified as being proper Violin-Mode fundamental resonances of the fibre, and the operation of the Violin-Mode detection system was validated. PMID:27475586

  2. Load-cell based characterization system for a "Violin-Mode" shadow-sensor in advanced LIGO suspensions

    NASA Astrophysics Data System (ADS)

    Lockerbie, N. A.; Tokmakov, K. V.

    2016-07-01

    The background to this work was a prototype shadow sensor, which was designed for retro-fitting to an advanced LIGO (Laser Interferometer Gravitational wave Observatory) test-mass/mirror suspension, in which 40 kg test-mass/mirrors are each suspended by four approximately 600 mm long by 0.4 mm diameter fused-silica suspension fibres. The shadow sensor comprised a LED source of Near InfraRed (NIR) radiation and a rectangular silicon photodiode detector, which, together, were to bracket the fibre under test. The aim was to detect transverse Violin-Mode resonances in the suspension fibres. Part of the testing procedure involved tensioning a silica fibre sample and translating it transversely through the illuminating NIR beam, so as to measure the DC responsivity of the detection system to fibre displacement. However, an equally important part of the procedure, reported here, was to keep the fibre under test stationary within the beam, whilst trying to detect low-level AC Violin-Mode resonances excited on the fibre, in order to confirm the primary function of the sensor. Therefore, a tensioning system, incorporating a load-cell readout, was built into the test fibre's holder. The fibre then was excited by a signal generator, audio power amplifier, and distant loudspeaker, and clear resonances were detected. A theory for the expected fundamental resonant frequency as a function of fibre tension was developed and is reported here, and this theory was found to match closely with the detected resonant frequencies as they varied with tension. Consequently, the resonances seen were identified as being proper Violin-Mode fundamental resonances of the fibre, and the operation of the Violin-Mode detection system was validated.

  3. The golden age of bio-logging: how animal-borne sensors are advancing the frontiers of ecology.

    PubMed

    Wilmers, Christopher C; Nickel, Barry; Bryce, Caleb M; Smith, Justine A; Wheat, Rachel E; Yovovich, Veronica

    2015-07-01

    Great leaps forward in scientific understanding are often spurred by innovations in technology. The explosion of miniature sensors that are driving the boom in consumer electronics, such as smart phones, gaming platforms, and wearable fitness devices, are now becoming available to ecologists for remotely monitoring the activities of wild animals. While half a century ago researchers were attaching balloons to the backs of seals to measure their movement, today ecologists have access to an arsenal of sensors that can continuously measure most aspects of an animal's state (e.g., location, behavior, caloric expenditure, interactions with other animals) and external environment (e.g., temperature, salinity, depth). This technology is advancing our ability to study animal ecology by allowing researchers to (1) answer questions about the physiology, behavior, and ecology of wild animals in situ that would have previously been limited to tests on model organisms in highly controlled settings, (2) study cryptic or wide-ranging animals that have previously evaded investigation, and (3) develop and test entirely new theories. Here we explore how ecologists are using these tools to answer new questions about the physiological performance, energetics, foraging, migration, habitat selection, and sociality of wild animals, as well as collect data on the environments in which they live. PMID:26378296

  4. Recent advances in the development of a self-powered wireless sensor network for structural health prognosis

    NASA Astrophysics Data System (ADS)

    Godinez-Azcuaga, Valery F.; Inman, Daniel J.; Ziehl, Paul H.; Giurgiutiu, Victor; Nanni, Antonio

    2011-04-01

    This paper presents the most recent advances in the development of a self powered wireless sensor network for steel and concrete bridges monitoring and prognosis. This five-year cross-disciplinary project includes development and deployment of a 4-channel acoustic emission wireless node powered by structural vibration and wind energy harvesting modules. In order to accomplish this ambitious goal, the project includes a series of tasks that encompassed a variety of developments such as ultra low power AE systems, energy harvester hardware and especial sensors for passive and active acoustic wave detection. Key studies on acoustic emission produced by corrosion on reinforced concrete and by crack propagation on steel components to develop diagnosis tools and models for bridge prognosis are also a part of the project activities. It is important to mention that the impact of this project extends beyond the area of bridge health monitoring. Several wireless prototype nodes have been already requested for applications on offshore oil platforms, composite ships, combat deployable bridges and wind turbines. This project was awarded to a joint venture formed by Mistras Group Inc, Virginia Tech, University of South Carolina and University of Miami and is sponsored through the NIST-TIP Grant #70NANB9H007.

  5. Design and implementation of a new autonomous sensor fish to support advanced hydropower development.

    PubMed

    Deng, Z D; Lu, J; Myjak, M J; Martinez, J J; Tian, C; Morris, S J; Carlson, T J; Zhou, D; Hou, H

    2014-11-01

    Acceleration in development of additional conventional hydropower requires tools and methods to perform laboratory and in-field validation of turbine performance and fish passage claims. The new-generation Sensor Fish has been developed with more capabilities to accommodate a wider range of users over a broader range of turbine designs and operating environments. It provides in situ measurements of three-dimensional (3D) linear accelerations, 3D rotational velocities, 3D orientation, pressure, and temperature at a sampling frequency of 2048 Hz. It also has an automatic floatation system and built-in radio-frequency transmitter for recovery. The relative errors of the pressure, acceleration, and rotational velocity were within ±2%, ±5%, and ±5%, respectively. The accuracy of orientation was within ±4° and accuracy of temperature was ±2 °C. The new-generation Sensor Fish is becoming a major technology and being deployed for evaluating the conditions for fish passage of turbines or other hydraulic structures in both the United States and several other countries. PMID:25430138

  6. An uncooled thermal-array-based detector as an advanced security sensor

    NASA Astrophysics Data System (ADS)

    Rimmer, Andrew N.

    2004-09-01

    A 16x16 un-cooled thermal array based detector (ABD) offers the prospect of a new generation of security sensors, with high false alarm rejection and the ability to detect, track and count the number of intruders. The IRISYS array provides the ability not simply to detect an intruder, but by tracking them as a true moving target discriminate between real and false alarm sources. Target processing is carried out within the sensor allowing the position and size of each target within the field of view to be generated. The location and size for each target is output as a low bandwidth data message suitable for transmission over alarm signalling networks. A central security management system or alarm receiving centre display would provide an operator with an intruder count per room, a pseudo 'visual' display of targets and locations, show target vectors on a graphical display and track targets from room to room, allowing an appropriate response to be initiated. Taking the same concepts into external detection, should allow discrimination of humans versus animals or vermin and afford a high level of reasoning to reject environmentally generated false alarms. In external detection applications using the ABD as a trigger for CCTV, intruder location data would be used to steer and zoom a PTZ camera to achieve an identification view. As auto tracking features are added to the latest dome cameras the ABD's ability to track and output simultaneous data from multiple targets will steer a camera between several intruders.

  7. Design and implementation of a new autonomous sensor fish to support advanced hydropower development

    NASA Astrophysics Data System (ADS)

    Deng, Z. D.; Lu, J.; Myjak, M. J.; Martinez, J. J.; Tian, C.; Morris, S. J.; Carlson, T. J.; Zhou, D.; Hou, H.

    2014-11-01

    Acceleration in development of additional conventional hydropower requires tools and methods to perform laboratory and in-field validation of turbine performance and fish passage claims. The new-generation Sensor Fish has been developed with more capabilities to accommodate a wider range of users over a broader range of turbine designs and operating environments. It provides in situ measurements of three-dimensional (3D) linear accelerations, 3D rotational velocities, 3D orientation, pressure, and temperature at a sampling frequency of 2048 Hz. It also has an automatic floatation system and built-in radio-frequency transmitter for recovery. The relative errors of the pressure, acceleration, and rotational velocity were within ±2%, ±5%, and ±5%, respectively. The accuracy of orientation was within ±4° and accuracy of temperature was ±2 °C. The new-generation Sensor Fish is becoming a major technology and being deployed for evaluating the conditions for fish passage of turbines or other hydraulic structures in both the United States and several other countries.

  8. Retrieval of atmospheric temperature and moisture vertical profiles from satellite Advanced Infrared Sounder radiances with a new regularization parameter selecting method

    NASA Astrophysics Data System (ADS)

    Zhang, Kun; Wu, Chunqiang; Li, Jun

    2016-06-01

    Considering the characteristics of nonlinear problems, a new method based on the L-curve method and including the concept of entropy was designed to select the regularization parameter in the one-dimensional variational analysis-based sounding retrieval method. In the first iteration, this method uses an empirical regularization parameter derived by minimizing the entropy of variables. During subsequent iterations, it uses the L-curve method to select the regularization parameter in the vicinity of the regularization parameter selected in the last iteration. The new method was employed to select the regularization parameter in retrieving atmospheric temperature and moisture profiles from Atmospheric Infrared Sounder radiance measurements selected from the first day of each month in 2008. The results show that compared with the original L-curve method, the new method yields 5.5% and 2.5% improvements on temperature and relative humidity profiles, respectively. Compared with the discrepancy principle method, the improvements on temperature and relative humidity profiles are 1.6% and 2.0%, respectively.

  9. Dynamic moisture permeation through clothing.

    PubMed

    Kakitsuba, N; Gaul, K; Michna, H; Mekjavic, I B

    1988-01-01

    Dynamic moisture permeation through clothing often occurs during thermal transience, causing an imbalance between evaporative heat loss from the skin (Esk) and that from the clothing surface (Ecl). A device was designed to observe Esk and Ecl simultaneously. It consists of two relative humidity sensors coupled with thermistors so that densities of water vapor at two points within the boundary layer can be calculated. The rate of local evaporation is then estimated from Fick's law of diffusion. Local evaporation rates from the skin and clothing surface at the chest, arm, and thigh were measured during exposure to controlled ambient temperatures varying from 20 degrees-40 degrees C. The subjects wore four different types of helicopter pilot suits: Nomex/Neoprene, Goretex, cotton ventile, and Nomex/Insulite. For the Goretex and cotton ventile suits, consisting of relatively permeable and hygroscopic fabrics, a sudden increase in Esk, exponential decay of Esk, and a gradual increase in Ecl were observed. These appear to be associated with, respectively, the onset of sweat secretion, moisture build-up within the clothing, and water gain in the fabric. Thus, the device may be useful for observing dynamic moisture permeation through clothing. PMID:3355466

  10. Microwave Moisture Measurement System for Hardwood Lumber Drying

    SciTech Connect

    Moschler, William W; Hanson, Gregory R

    2008-09-01

    The goal of this project was to develop a prototype microwave-based moisture sensor system suitable for the kiln drying of hardwood lumber. The moisture sensors developed are battery powered and are capable of communicating with a host kiln control system via spread spectrum wireless communications. We have developed two designs of the sensors working at 4.5 to 6 GHz with linear response to moisture content (MC) over a range of 6-100%. These sensors allow us to make a swept frequency microwave transmission measurement through a small area of a board. Using the prototype electronics and sensors, we have obtained measurements of MC over the above MC range for red oak and yellow poplar with standard deviations of less than 1.5% MC. We have developed data for board thickness corrections and for temperature corrections for the MC measurement system.

  11. Wireless device for monitoring the temperature - moisture regime in situ

    NASA Astrophysics Data System (ADS)

    Hudec, Ján; Štofanik, Vladimír; Vretenár, Viliam; Kubičár, Ľudovít

    2014-05-01

    This contribution presents the wireless device for monitoring the temperature - moisture regime in situ. For the monitoring so called moisture sensor is used. Principle of moisture sensor is based on measuring the thermal conductivity. Moisture sensor has cylindrical shape with about 20 mm diameter and 20 mm length. It is made of porous material identical to the monitored object. The thermal conductivity is measured by hot-ball method. Hot-ball method is patented invention of the Institute of Physic SAS. It utilizes a small ball, diameter up to 2 mm, in which sensing elements are incorporated. The ball produces heat spreading into surrounding material, in our case into body of the moisture sensor. Temperature of the ball is measured simultaneously. Then change of the temperature, in steady state, is inversely proportional to the thermal conductivity. Such moisture sensor is inserted into monitored wall. Thermophysical properties of porous material are function of moisture. Moisture sensors are calibrated for dry and water saturated state. Whole the system is primarily intended to do long-term monitoring. Design of a new electronic device was needed for this innovative method. It covers all needed operations for measurement. For example energizing hot-ball sensor, measuring its response, storing the measured data and wireless data transmission. The unit is able to set parameters of measurement via wireless access as well. This contribution also includes the description of construction and another features of the wireless measurement system dedicated for this task. Possibilities and functionality of the system is demonstrated by actual monitoring of the tower of St. Martin's Cathedral in Bratislava. Correlations with surrounding meteorological conditions are presented. Some of them can be also measured by our system, right in the monitoring place.

  12. Microwave remote sensing of soil moisture, volume 1. [Guymon, Oklahoma and Dalhart, Texas

    NASA Technical Reports Server (NTRS)

    Mcfarland, M. J. (Principal Investigator); Theis, S. W.; Rosenthal, W. D.; Jones, C. L.

    1982-01-01

    Multifrequency sensor data from NASA's C-130 aircraft were used to determine which of the all weather microwave sensors demonstrated the highest correlation to surface soil moisture over optimal bare soil conditions, and to develop and test techniques which use visible/infrared sensors to compensate for the vegetation effect in this sensor's response to soil moisture. The L-band passive microwave radiometer was found to be the most suitable single sensor system to estimate soil moisture over bare fields. The perpendicular vegetation index (PVI) as determined from the visible/infrared sensors was useful as a measure of the vegetation effect on the L-band radiometer response to soil moisture. A linear equation was developed to estimate percent field capacity as a function of L-band emissivity and the vegetation index. The prediction algorithm improves the estimation of moisture significantly over predictions from L-band emissivity alone.

  13. Airborne Coherent Lidar for Advanced In-Flight Measurements (ACLAIM) Flight Testing of the Lidar Sensor

    NASA Technical Reports Server (NTRS)

    Soreide, David C.; Bogue, Rodney K.; Ehernberger, L. J.; Hannon, Stephen M.; Bowdle, David A.

    2000-01-01

    The purpose of the ACLAIM program is ultimately to establish the viability of light detection and ranging (lidar) as a forward-looking sensor for turbulence. The goals of this flight test are to: 1) demonstrate that the ACLAIM lidar system operates reliably in a flight test environment, 2) measure the performance of the lidar as a function of the aerosol backscatter coefficient (beta), 3) use the lidar system to measure atmospheric turbulence and compare these measurements to onboard gust measurements, and 4) make measurements of the aerosol backscatter coefficient, its probability distribution and spatial distribution. The scope of this paper is to briefly describe the ACLAIM system and present examples of ACLAIM operation in flight, including comparisons with independent measurements of wind gusts, gust-induced normal acceleration, and the derived eddy dissipation rate.

  14. Design and Implementation of a new Autonomous Sensor Fish to Support Advanced Hydropower Development

    SciTech Connect

    Deng, Zhiqun; Lu, Jun; Myjak, Mitchell J.; Martinez, Jayson J.; Tian, Chuan; Morris, Scott J.; Carlson, Thomas J.; Zhou, Da; Hou, Hongfei

    2014-11-04

    Acceleration in development of additional conventional hydropower requires tools and methods to perform laboratory and in-field validation of turbine performance and fish passage claims. The new-generation Sensor Fish has been developed with more capabilities to accommodate a wider range of users over a wider range of turbine designs and operating environments. It provides in situ measurements of three dimensional (3D) accelerations, 3D rotational velocities, 3D orientation, pressure, and temperature at a sampling frequency of 2048 Hz. It also has an automatic floatation system and built-in radio frequency transmitter for recovery. The relative errors of the pressure, acceleration and rotational velocity were within ±2%, ±5%, and ±5%, respectively. The accuracy of orientation was within ±4° and accuracy of temperature was ±2°C. It is being deployed to evaluate the biological effects of turbines or other hydraulic structures in several countries.

  15. Advances in Lead-Free Piezoelectric Materials for Sensors and Actuators

    PubMed Central

    Aksel, Elena; Jones, Jacob L.

    2010-01-01

    Piezoelectrics have widespread use in today’s sensor and actuator technologies. However, most commercially available piezoelectric materials, e.g., Pb [ZrxTi1−x] O3 (PZT), are comprised of more than 60 weight percent lead (Pb). Due to its harmful effects, there is a strong impetus to identify new lead-free replacement materials with comparable properties to those of PZT. This review highlights recent developments in several lead-free piezoelectric materials including BaTiO3, Na0.5Bi0.5TiO3, K0.5Bi0.5TiO3, Na0.5K0.5NbO3, and their solid solutions. The factors that contribute to strong piezoelectric behavior are described and a summary of the properties for the various systems is provided. PMID:22294907

  16. Advanced shortwave infrared and Raman hyperspectral sensors for homeland security and law enforcement operations

    NASA Astrophysics Data System (ADS)

    Klueva, Oksana; Nelson, Matthew P.; Gardner, Charles W.; Gomer, Nathaniel R.

    2015-05-01

    Proliferation of chemical and explosive threats as well as illicit drugs continues to be an escalating danger to civilian and military personnel. Conventional means of detecting and identifying hazardous materials often require the use of reagents and/or physical sampling, which is a time-consuming, costly and often dangerous process. Stand-off detection allows the operator to detect threat residues from a safer distance minimizing danger to people and equipment. Current fielded technologies for standoff detection of chemical and explosive threats are challenged by low area search rates, poor targeting efficiency, lack of sensitivity and specificity or use of costly and potentially unsafe equipment such as lasers. A demand exists for stand-off systems that are fast, safe, reliable and user-friendly. To address this need, ChemImage Sensor Systems™ (CISS) has developed reagent-less, non-contact, non-destructive sensors for the real-time detection of hazardous materials based on widefield shortwave infrared (SWIR) and Raman hyperspectral imaging (HSI). Hyperspectral imaging enables automated target detection displayed in the form of image making result analysis intuitive and user-friendly. Application of the CISS' SWIR-HSI and Raman sensing technologies to Homeland Security and Law Enforcement for standoff detection of homemade explosives and illicit drugs and their precursors in vehicle and personnel checkpoints is discussed. Sensing technologies include a portable, robot-mounted and standalone variants of the technology. Test data is shown that supports the use of SWIR and Raman HSI for explosive and drug screening at checkpoints as well as screening for explosives and drugs at suspected clandestine manufacturing facilities.

  17. Temporal changes of spatial soil moisture patterns: controlling factors explained with a multidisciplinary approach

    NASA Astrophysics Data System (ADS)

    Martini, Edoardo; Wollschläger, Ute; Kögler, Simon; Behrens, Thorsten; Dietrich, Peter; Reinstorf, Frido; Schmidt, Karsten; Weiler, Markus; Werban, Ulrike; Zacharias, Steffen

    2016-04-01

    Characterizing the spatial patterns of soil moisture is critical for hydrological and meteorological models, as soil moisture is a key variable that controls matter and energy fluxes and soil-vegetation-atmosphere exchange processes. Deriving detailed process understanding at the hillslope scale is not trivial, because of the temporal variability of local soil moisture dynamics. Nevertheless, it remains a challenge to provide adequate information on the temporal variability of soil moisture and its controlling factors. Recent advances in wireless sensor technology allow monitoring of soil moisture dynamics with high temporal resolution at varying scales. In addition, mobile geophysical methods such as electromagnetic induction (EMI) have been widely used for mapping soil water content at the field scale with high spatial resolution, as being related to soil apparent electrical conductivity (ECa). The objective of this study was to characterize the spatial and temporal pattern of soil moisture at the hillslope scale and to infer the controlling hydrological processes, integrating well established and innovative sensing techniques, as well as new statistical methods. We combined soil hydrological and pedological expertise with geophysical measurements and methods from digital soil mapping for designing a wireless soil moisture monitoring network. For a hillslope site within the Schäfertal catchment (Central Germany), soil water dynamics were observed during 14 months, and soil ECa was mapped on seven occasions whithin this period of time using an EM38-DD device. Using the Spearman rank correlation coefficient, we described the temporal persistence of a dry and a wet characteristic state of soil moisture as well as the switching mechanisms, inferring the local properties that control the observed spatial patterns and the hydrological processes driving the transitions. Based on this, we evaluated the use of EMI for mapping the spatial pattern of soil moisture under

  18. Assimilation of Passive and Active Microwave Soil Moisture Retrievals

    NASA Technical Reports Server (NTRS)

    Draper, C. S.; Reichle, R. H.; DeLannoy, G. J. M.; Liu, Q.

    2012-01-01

    Root-zone soil moisture is an important control over the partition of land surface energy and moisture, and the assimilation of remotely sensed near-surface soil moisture has been shown to improve model profile soil moisture [1]. To date, efforts to assimilate remotely sensed near-surface soil moisture at large scales have focused on soil moisture derived from the passive microwave Advanced Microwave Scanning Radiometer (AMSR-E) and the active Advanced Scatterometer (ASCAT; together with its predecessor on the European Remote Sensing satellites (ERS. The assimilation of passive and active microwave soil moisture observations has not yet been directly compared, and so this study compares the impact of assimilating ASCAT and AMSR-E soil moisture data, both separately and together. Since the soil moisture retrieval skill from active and passive microwave data is thought to differ according to surface characteristics [2], the impact of each assimilation on the model soil moisture skill is assessed according to land cover type, by comparison to in situ soil moisture observations.

  19. Development of sensors for ceramic components in advanced propulsion systems: Survey and evaluation of measurement techniques for temperature, strain and heat flux for ceramic components in advanced propulsion systems

    NASA Technical Reports Server (NTRS)

    Atkinson, W. H.; Cyr, M. A.; Strange, R. R.

    1988-01-01

    The report presents the final results of Tasks 1 and 2, Development of Sensors for Ceramic Components in Advanced Propulsion Systems (NASA program NAS3-25141). During Task 1, an extensive survey was conducted of sensor concepts which have the potential for measuring surface temperature, strain and heat flux on ceramic components for advanced propulsion systems. Each sensor concept was analyzed and evaluated under Task 2; sensor concepts were then recommended for further development. For temperature measurement, both pyrometry and thermographic phosphors are recommended for measurements up to and beyond the melting point of ceramic materials. For lower temperature test programs, the thin-film techniques offer advantages in the installation of temperature sensors. Optical strain measurement techniques are recommended because they offer the possibility of being useful at very high temperature levels. Techniques for the measurement of heat flux are recommended for development based on both a surface mounted sensor and the measurement of the temperature differential across a portion of a ceramic component or metallic substrate.

  20. Soil moisture modeling review

    NASA Technical Reports Server (NTRS)

    Hildreth, W. W.

    1978-01-01

    A determination of the state of the art in soil moisture transport modeling based on physical or physiological principles was made. It was found that soil moisture models based on physical principles have been under development for more than 10 years. However, these models were shown to represent infiltration and redistribution of soil moisture quite well. Evapotranspiration has not been as adequately incorporated into the models.

  1. Remote sensing of an agricultural soil moisture network in Walnut Creek, Iowa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The calibration and validation of soil moisture remote sensing products is complicated by the logistics of installing a soil moisture network for a long term period in an active landscape. Usually soil moisture sensors are added to existing precipitation networks which have as a singular requiremen...

  2. Moisturizers for Acne

    PubMed Central

    Chularojanamontri, Leena; Tuchinda, Papapit; Kulthanan, Kanokvalai

    2014-01-01

    Acne is a chronic inflammatory disease of the pilosebaceous unit that affects almost all teenagers. Different treatments offer different modes of action, but aim to target acne pathology. Topical therapies, such as benzoyl peroxide, retinoids, antibiotics with alcohol-based preparations, and salicylic acid, can cause skin irritation resulting in a lack of patient adherence. Some physicians recommend patients use moisturizers as adjunctive treatment of acne, especially when either topical benzoyl peroxide or a retinoid is prescribed. Furthermore, some evidence shows that moisturizers can contribute independently to improve signs and symptoms of acne. Moisturizers contain three main properties, which are occlusive, humectant, and emollient effects. Currently, many moisturizers claim to be suitable for acne treatment. This article aims to provide a review of the active ingredients and properties of those moisturizers. Fifty-two moisturizers for acne were included for analysis. Most of the products (92%) have anti-inflammatory properties apart from occlusive, humectant, and emollient effects. Anti-acne medications, including salicylic acid, benzoyl peroxide, and retinol, were found respectively in 35, 10, and 8 percent of the moisturizer products containing anti-inflammatory properties. More than half of the products contain dimethicone and/or glycerin for its moisturizer property. Aloe vera and witch hazel are botanical anti-inflammatories that were commonly found in this study. Scientific data regarding some ingredients are discussed to provide a guide for physicians in selecting moisturizers for acne patients. PMID:24847408

  3. Aircraft scatterometer observations of soil moisture on rangeland watersheds

    NASA Technical Reports Server (NTRS)

    Jackson, T. J.; Oneill, P. E.

    1983-01-01

    Extensive studies conducted by several researchers using truck-mounted active microwave sensors have shown the sensitivity of these sensors to soil moisture variations. The logical extension of these results is the evaluation of similar systems at lower resolutions typical of operational systems. Data collected during a series of aircraft flights in 1978 and 1980 over four rangeland watersheds located near Chickasha, Oklahoma, were analyzed in this study. These data included scatterometer measurements made at 1.6 and 4.75 GHz using a NASA aircraft and ground observations of soil moisture for a wide range of moisture conditions. Data were analyzed for consistency and compared to previous truck and aircraft results. Results indicate that the sensor system is capable of providing consistent estimates of soil moisture under the conditions tested.

  4. Soil moisture sensing with microwave techniques

    NASA Technical Reports Server (NTRS)

    Schmugge, T.

    1980-01-01

    Microwave approaches for the remote sensing of soil moisture are discussed, with the advantages described as follows: (1) the all-weather capability, (2) the greater penetration depth into the soil and through vegetation than with optical or infrared sensors, and (3) the large changes in the dielectric properties of soil produced by changes in water content. Both active and passive microwave approaches are discussed. The dependence of the relationship between microwave response and soil moisture on such things as soil texture, surface roughness, vegetative cover and nonuniform moisture and temperature profiles is analyzed from both the experimental and theoretical viewpoints. The dielectric properties of the soil are analyzed quantitatively, as these control the reflective and emissive properties of the soil surface, and a model for estimating a soil's dielectric properties from its texture and moisture content is also presented. Emissivity is calculated using the Fresnel equation of electromagnetic theory, and reflectivity is shown to be decreased by surface roughness, while the backscatter coefficient increases. It is demonstrated, that microwave radiometers are sensitive to soil moisture for a wide range of surface conditions, and that the longer wavelengths are best for soil moisture sensing.

  5. Advances in utilization of structurally integrated sensor networks for health monitoring in commercial applications

    NASA Astrophysics Data System (ADS)

    Lin, Mark; Kumar, Amrita; Qing, Xinlin; Beard, Shawn J.

    2002-07-01

    Structural health monitoring is a new technology that has been increasingly evaluated by the industry as a potential approach to improve the cost and ease of structural inspection. By improving structural inspection, structures can be made safer and more reliable, thus reducing the cost of structure ownership. Acellent Technologies is developing tools for structural health monitoring. The tools Acellent is offering are the SMART Layer and the SMART Suitcase. The SMART Layer is a flexible layer with a distributed array of piezoelectric transducers made using the printed circuit process that allows easy installation onto structures for in-situ sensing. The SMART Suitcase is an instrument that can interact with the SMART Layer and process the information collected from the structures. Acellent has been providing the system to researchers and companies to try out this new technique. Currently, this system is being evaluated by aircraft manufacturers for monitoring fatigue cracks from rivet holes, by an automotive company for inspecting flaws in composite/foam components, and by aerospace companies for detecting damages in composite/honeycomb sandwich structures. Other recent developments include the addition of fiber-optic sensors onto the SMART Layer and proving the SMART Layer for composite RTM process.

  6. Field Effect Sensors for Nucleic Acid Detection: Recent Advances and Future Perspectives

    PubMed Central

    Veigas, Bruno; Fortunato, Elvira; Baptista, Pedro V.

    2015-01-01

    In the last decade the use of field-effect-based devices has become a basic structural element in a new generation of biosensors that allow label-free DNA analysis. In particular, ion sensitive field effect transistors (FET) are the basis for the development of radical new approaches for the specific detection and characterization of DNA due to FETs’ greater signal-to-noise ratio, fast measurement capabilities, and possibility to be included in portable instrumentation. Reliable molecular characterization of DNA and/or RNA is vital for disease diagnostics and to follow up alterations in gene expression profiles. FET biosensors may become a relevant tool for molecular diagnostics and at point-of-care. The development of these devices and strategies should be carefully designed, as biomolecular recognition and detection events must occur within the Debye length. This limitation is sometimes considered to be fundamental for FET devices and considerable efforts have been made to develop better architectures. Herein we review the use of field effect sensors for nucleic acid detection strategies—from production and functionalization to integration in molecular diagnostics platforms, with special focus on those that have made their way into the diagnostics lab. PMID:25946631

  7. Soil Moisture Monitoring at Watershed Scale in Eastern India

    NASA Astrophysics Data System (ADS)

    Panda, R. K.

    2015-12-01

    Understanding the spatio-temporal variation of soil moisture on time scales that range from minute to decades on the watershed scale is important for the hydrological, meteorological and agricultural communities. Lack of reliable, longterm soil moisture datasets in developing countries like India, is a bottleneck for soil moisture analysis and prediction. Recognizing the need of continuous, automated in-situ soil moisture observations, three in-situ soil moisture test-beds have been established in an agricultural watershed of the Eastern India. Test-beds have been specifically designed to capture the root zone soil moisture dynamic at different crop fields under both surplus and water deficit conditions in low, medium and up-lands of the study region. Both volumetric and tensiometric method based sensors, Campbell Scientific soil water content reflectometer (CS650) and matric potential sensor (CS229) are installed at depths of 5, 15, 30, 60 and 100 cm below the surface. GPRS communication modems were installed at each station for remote communication from the data loggers (Campbell Scientific, CR1000) for automatic data collection. To achieve a better understanding of the spatial variation of the soil moisture on watershed scale, the strategic ground-based surface measurements were made in diverse landscape using portable impedance probe. The primary aim of spatial and temporal scale soil moisture measurement is to validate current remote sensing products of Soil Moisture Active Passive (SMAP). In order to improve validation procedure, the soil texture and soil hydraulic parameters are also estimated across the spatial scales to develop dynamic relationship between these parameters. Herein, the strategies for the site selection, calibration of the soil moisture sensors, ground-based soil moisture monitoring, hydraulic properties estimation at spatial scale and the quality assurance techniques applied to the observations are provided.

  8. Soil moisture at watershed scale: Remote sensing techniques

    NASA Astrophysics Data System (ADS)

    Fang, Bin; Lakshmi, Venkat

    2014-08-01

    Soil moisture at high spatial resolution is required for various land processes related studies. However, currently the resolution of passive microwave retrieved soil moisture is low - around 25 km. To solve this problem, a soil moisture disaggregation algorithm based on thermal inertia relationship between daily temperature change and average soil moisture modulated by vegetation conditions has been formulated. This algorithm was applied to the AMSR-E (Advanced Microwave Scanning Radiometer - Earth Observing System) as well as SMOS (Soil Moisture and Ocean Salinity satellite) to produce the 1 km downscaled soil moisture over the Little Washita Watershed in Oklahoma for the growing season in 2010 and 2011.The disaggregated soil moisture has been compared to in situ observations. The results of this approach are very encouraging.

  9. NASA Soil Moisture Data Products and Their Incorporation in DREAM

    NASA Technical Reports Server (NTRS)

    Blonski, Slawomir; Holland, Donald; Henderson, Vaneshette

    2005-01-01

    NASA provides soil moisture data products that include observations from the Advanced Microwave Scanning Radiometer on the Earth Observing System Aqua satellite, field measurements from the Soil Moisture Experiment campaigns, and model predictions from the Land Information System and the Goddard Earth Observing System Data Assimilation System. Incorporation of the NASA soil moisture products in the Dust Regional Atmospheric Model is possible through use of the satellite observations of soil moisture to set initial conditions for the dust simulations. An additional comparison of satellite soil moisture observations with mesoscale atmospheric dynamics modeling is recommended. Such a comparison would validate the use of NASA soil moisture data in applications and support acceptance of satellite soil moisture data assimilation in weather and climate modeling.

  10. Multifrequency remote sensing of soil moisture. [Guymon, Oklahoma and Dalhart, Texas

    NASA Technical Reports Server (NTRS)

    Theis, S. W.; Mcfarland, M. J.; Rosenthal, W. D.; Jones, C. L. (Principal Investigator)

    1982-01-01

    Multifrequency sensor data collected at Guymon, Oklahoma and Dalhart, Texas using NASA's C-130 aircraft were used to determine which of the all-weather microwave sensors demonstrated the highest correlation to surface soil moisture over optimal bare soil conditions, and to develop and test techniques which use visible/infrared sensors to compensate for the vegetation effect in this sensor's response to soil moisture. The L-band passive microwave radiometer was found to be the most suitable single sensor system to estimate soil moisture over bare fields. In comparison to other active and passive microwave sensors the L-band radiometer (1) was influenced least by ranges in surface roughness; (2) demonstrated the most sensitivity to soil moisture differences in terms of the range of return from the full range of soil moisture; and (3) was less sensitive to errors in measurement in relation to the range of sensor response. L-band emissivity related more strongly to soil moisture when moisture was expressed as percent of field capacity. The perpendicular vegetation index as determined from the visible/infrared sensors was useful as a measure of the vegetation effect on the L-band radiometer response to soil moisture.

  11. Ionomer-coated electrodes and nanoelectrode ensembles as electrochemical environmental sensors: recent advances and prospects.

    PubMed

    Ugo, Paolo; Moretto, Ligia Maria; Vezzà, Francesca

    2002-11-15

    This Minireview focuses on recent advances in the use of ionomer-coated electrodes and nanoelectrode ensembles for the determination of redox ions at trace concentration level with special stress on applications for environmental monitoring. After an overview on the most recent developments of ionomer-coated electrodes, attention is directed towards their use for speciation analysis in environmental samples. In particular, some examples such as the selective determination of inorganic and metallorganic species of different toxicity and the redox state speciation of multiply charged ions are discussed. The second part of the Minireview deals with the development and electroanalytical use of a new kind of nanostructured electrode, named nanoelectrode ensembles, which are prepared by template synthesis within the pores of microporous guest membranes. Advantages, peculiarities, and limits of such devices are discussed together with perspectives for their use in electroanalytical sensing at trace and ultratrace concentration levels in environmental samples. PMID:12503131

  12. Advanced fire observation by the Intelligent Infrared Sensor prototype FOCUS on the International Space Station

    NASA Astrophysics Data System (ADS)

    Oertel, D.; Haschberger, P.; Tank, V.; Lanzl, F.; Zhukov, B.; Jahn, H.; Briess, K.; Lorenz, E.; Roeser, H.-P.; Ginati, A.; Tobehn, C.; Schulte in den Bäumen, J.; Christmann, U.

    1999-01-01

    Current and planned operational space-borne Earth observation systems provide spatially, radiometrically or temporally crude data for the detection and monitoring of high temperature phenomena on the surface of our planet. High Temperature Events (HTE) very often cause environmental disasters. Such HTE are forest and savannah fires, fires of open coal mines, volcanic activities and others (e.g. fires of oil wells, pipelines etc.). A simultaneous co-registration of a combination of infrared (IR) and visible (VIS) channels is the key for a reliable autonomous on-board detection of High Temperature Events (HTE) on Earth surface, such as vegetation fires and volcano eruptions. This is the main feature of the FOCUS experiment. Furthermore there are ecology-oriented objectives of the FOCUS experiment mainly related to spectrometric/imaging remote inspection and parameter extraction of selected HTEs, and to the assessment of some ecological consequences of HTEs, such as aerosol and gas emission. Based on own experimental work and supported by Co-Investigators from Italy, Greece, France, Spain, Russia and Germany, DLR proposed in 1997 to use the International Space Station (ISS) in its early utilization phase as a platform and test-bed for an Intelligent Infrared Sensor prototype FOCUS of a future Environmental Disaster Recognition Satellite System. FOCUS is considered by ESA as an important mission combining a number of proven technologies and observation techniques to provide the scientific and operational user community with key data for the classification and monitoring of forest fires. FOCUS was selected as one of five European ``Groupings'' to be flown as an externally mounted payload during the early utilisation phase of the ISS. The FOCUS Phase A Study will be performed by OHB-System, DLR and Zeiss from September 1998 until May 1999.

  13. Combination moisture and hydrogen getter

    DOEpatents

    Harrah, L.A.; Mead, K.E.; Smith, H.M.

    1983-09-20

    A combination moisture and hydrogen getter comprises (a) a moisture getter comprising a readily oxidizable metal; and (b) a hydrogen getter comprising (1) a solid acetylenic compound and (2) a hydrogenation catalyst. A method of scavenging moisture from a closed container uses the combination moisture and hydrogen getter to irreversibly chemically reduce the moisture and chemically bind the resultant hydrogen.

  14. Combination moisture and hydrogen getter

    DOEpatents

    Not Available

    1982-04-29

    A combination moisture and hydrogen getter comprises (a) a moisture getter comprising a readily oxidizable metal; and (b) a hydrogen getter comprising (i) a solid acetylenic compound and (ii) a hydrogenation catalyst. A method of scavenging moisture from a closed container uses the combination moisture and hydrogen getter to irreversibly chemically reduce the moisture and chemically bind the reusltant hydrogen.

  15. Combination moisture and hydrogen getter

    DOEpatents

    Harrah, Larry A.; Mead, Keith E.; Smith, Henry M.

    1983-01-01

    A combination moisture and hydrogen getter comprises (a) a moisture getter comprising a readily oxidizable metal; and (b) a hydrogen getter comprising (i) a solid acetylenic compound and (ii) a hydrogenation catalyst. A method of scavenging moisture from a closed container uses the combination moisture and hydrogen getter to irreversibly chemically reduce the moisture and chemically bind the resultant hydrogen.

  16. Moisture Research - Optimizing Wall Assemblies

    SciTech Connect

    Arena, Lois; Mantha, Pallavi

    2013-05-01

    In this project, the Consortium for Advanced Residential Buildings (CARB) team evaluated several different configurations of wall assemblies to determine the accuracy of moisture modeling and make recommendations to ensure durable, efficient assemblies. WUFI and THERM were used to model the hygrothermal and heat transfer characteristics of these walls. Wall assemblies evaluated included code minimum walls using spray foam insulation and fiberglass batts, high R-value walls at least 12 in. thick (R-40 and R-60 assemblies), and brick walls with interior insulation.

  17. An advanced AFM sensor: its profile accuracy and low probe wear property for high aspect ratio patterns

    NASA Astrophysics Data System (ADS)

    Watanabe, Masahiro; Baba, Shuichi; Nakata, Toshihiko; Kurenuma, Toru; Kunitomo, Yuichi; Edamura, Manabu

    2007-03-01

    Design rule shrinkage and wider adoption of new device structures such as STI, copper damascene interconnects, and deep trench structures have made the need for in-line process monitoring of step heights and profiles of device structures more urgent. To monitor active device patterns, as opposed to test patterns as in OCD, AFM is the only non-destructive 3D monitoring tool. The barriers to using AFM in-line monitoring are its slow throughput and the accuracy degradation associated with probe tip wear and spike noise caused by unwanted oscillation on the steep slopes of high-aspect-ratio patterns. Our proprietary AFM scanning method, StepIn TM mode, is the method best suited to measuring high-aspect-ratio pattern profiles. Because the probe is not dragged on the sample surface as in conventional AFM, the profile trace fidelity across steep slopes is excellent. Because the probe does not oscillate and hit the sample at a high frequency, as in AC scanning mode, this mode is free from unwanted spurious noises on steep sample slopes and incurs extremely little probe tip wear. To take full advantage of the above properties, we have developed an AFM sensor that is optimized for in-line use and produces accurate profile data at high speeds and incurs little probe tip wear. The control scheme we have developed for the AFM sensor, which we call "Advanced StepIn TM", elaborately analyses the contact force signal, enabling efficient probe tip scanning and a low and stable contact force. With a developed AFM sensor that realizes this concept, we conducted an intensive evaluation on the effect of low and stable contact force scan. Probes with HDC (high density carbon) tips were used for the evaluation. The experiment proves that low contact force enhances the measured profile fidelity by preventing probe tip slip on steep slopes. Dynamics simulation of these phenomena was also conducted, and its results agreed well with the experimental results. The low contact force scan also

  18. Bulk Density and Soil Moisture Sensors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil bulk density is a good indicator of problems of root penetration, soil aeration, and water infiltration. Knowledge of soil water content is important to understand crop water use, leaching of chemicals, and soil trafficability. The purpose of this presentation is to detail step-by-step how to m...

  19. Ground measurements and satellite observations of soil moisture over the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Van der Velde, R.; Su, Z.; Wen, J.; Yang, K.; Ma, Y.

    2012-04-01

    The importance of the Tibetan Plateau for the atmospheric circulation and the development of large-scale weather systems over the Asian continent has been widely acknowledged. Due to its wide extent and high elevation, the Plateau plays a critical role in directing moist air from the eastern Indian Ocean and Bay of Bengal towards central China. Heat and moisture sources from the Plateau affect the flow of moist air from the ocean and seas creating a so-called "air pump" that influences the onset and maintenance of the Asian monsoon. In a changing climate, global warming will also change the partitioning of radiation into sensible and latent heat over the Plateau and, thus, the Tibetan air pump. A key land surface state controlling interactions between the land surface and atmosphere is soil moisture. Being highly variable in both space and time, it is not feasible to base large-scale soil moisture monitoring programmes on in-situ measurements alone. Hence, estimates derived from satellite observations can complement ground measuring networks by providing insight into spatial soil moisture distributions across large scales. In this study, we report on the development of large-scale ground measuring soil moisture/temperature networks across the Tibetan Plateau and their application in validating soil moisture retrieved from both active and passive microwave observations. An Advanced Synthetic Aperture Radar (ASAR) data set consisting of 150 scenes collected in the period from April 2005 to September 2007 is used as a demonstration of high resolution (100 m) soil moisture mapping over the central part of the Tibetan Plateau. Special Sensor Microwave/Imager (SSM/I) passive microwave observations from 1987 to 2008 are utilized to derive long-term soil moisture trends across the entire Tibetan Plateau. The soil moisture estimates from both ASAR and SSM/I are in agreement with our in-situ measurements. This study highlights the complementary information that can be

  20. Online analysis of H2S and SO2 via advanced mid-infrared gas sensors.

    PubMed

    Petruci, João Flavio da Silveira; Wilk, Andreas; Cardoso, Arnaldo Alves; Mizaikoff, Boris

    2015-10-01

    Volatile sulfur compounds (VSCs) are among the most prevalent emitted pollutants in urban and rural atmospheres. Mainly because of the versatility of sulfur regarding its oxidation state (2- to 6+), VSCs are present in a wide variety of redox-environments, concentration levels, and molar ratios. Among the VSCs, hydrogen sulfide and sulfur dioxide are considered most relevant and have simultaneously been detected within naturally and anthropogenically caused emission events (e.g., volcano emissions, food production and industries, coal pyrolysis, and various biological activities). Next to their presence as pollutants, changes within their molar ratio may also indicate natural anomalies. Prior to analysis, H2S- and SO2-containing samples are usually preconcentrated via solid sorbents and are then detected by gas chromatographic techniques. However, such analytical strategies may be of limited selectivity, and the dimensions and operation modalities of the involved instruments prevent routine field usage. In this contribution, we therefore describe an innovative portable mid-infrared chemical sensor for simultaneously determining and quantifying gaseous H2S and SO2 via coupling a substrate-integrated hollow waveguides (iHWG) serving as a highly miniaturized mid-infrared photon conduit and gas cell with a custom-made preconcentration tube and an in-line UV-converter device. Both species were collected onto a solid sorbent within the preconcentrator and then released by thermal desorption into the UV-device. Hydrogen sulfide is detected by UV-assisted quantitative conversion of the rather weak IR-absorber H2S into SO2, which provides a significantly more pronounced and distinctively detectable rovibrational signature. Modulation of the UV-device system (i.e., UV-lamp on/off) enables discriminating between SO2 generated from H2S conversion and abundant SO2 signals. After optimization of the operational parameters, calibrations in the range of 0.75-10 ppmv with a limit