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Sample records for airborne high sensitivity

  1. High sensitive airborne radioiodine monitor.

    PubMed

    Ogata, Yoshimune; Yamasaki, Tadashi; Hanafusa, Ryuji

    2013-11-01

    Airborne radioiodine monitoring includes a problem in that commercial radioactive gas monitors have inadequate sensitivity. To solve this problem, we designed a highly sensitive monitoring system. The higher counting efficiency and lower background made it possible to perform the low-level monitoring. The characteristics of the system were investigated using gaseous (125)I. The minimum detectable activity concentration was 1 × 10(-4)Bq cm(-3) for 1 min counting, which is one tenth of the legal limit for the radiation controlled areas in Japan. PMID:23602709

  2. Compact Highly Sensitive Multi-species Airborne Mid-IR Spectrometer

    SciTech Connect

    Richter, Dirk; Weibring, P.; Walega, J.; Fried, Alan; Spuler, Scott M.; Taubman, Matthew S.

    2015-02-01

    We report on the development and airborne field deployment of a mid-IR laser based spectrometer. The instrument was configured for the simultaneous in-situ detection of formaldehyde (CH2O) and ethane (C2H6). Numerous mechanical, optical, electronic, and software improvements over a previous instrument design resulted in reliable highly sensitive airborne operation with long stability times yielding 90% airborne measurement coverage during the recent air quality study over the Colorado front range, FRAPPÉ 2014. Airborne detection sensitivities of ~ 15 pptv (C2H6) and ~40 pptv (CH2O) were generally obtained for 1 s of averaging for simultaneous detection.

  3. HIGHLY SENSITIVE BIOASSAYS FOR EVALUATING AIRBORNE MUTAGENS INDOORS

    EPA Science Inventory

    The standard mutagenicity bioassays that are readily applied to the valuation of outdoor air samples collected by high volume samplers are not efficiently sensitive to measure the mutagenicity of low volume air samples collected indoors. wo microsuspension mutation assays using v...

  4. Development of a tunable mid-IR difference frequency laser source for highly sensitive airborne trace gas detection

    NASA Astrophysics Data System (ADS)

    Richter, D.; Fried, A.; Wert, B. P.; Walega, J. G.; Tittel, F. K.

    The development of a compact tunable mid-IR laser system at 3.5 μm for quantitative airborne spectroscopic trace gas absorption measurements is reported. The mid-IR laser system is based on difference frequency generation (DFG) in periodically poled LiNbO3 and utilizes optical fiber amplified near-IR diode and fiber lasers as pump sources operating at 1083 nm and 1562 nm, respectively. This paper describes the optical sensor architecture, performance characteristics of individual pump lasers and DFG, as well as its application to wavelength modulation spectroscopy employing an astigmatic Herriott multi-pass gas absorption cell. This compact system permits detection of formaldehyde with a minimal detectable concentration (1σ replicate precision) of 74 parts-per-trillion by volume (pptv) for 1 min of averaging time and was achieved using calibrated gas standards, zero air background and rapid dual-beam subtraction. This corresponds to a pathlength-normalized replicate fractional absorption sensitivity of 2.5×10-10 cm-1.

  5. Development of a tunable mid-IR difference frequency laser source for highly sensitive airborne trace gas detection.

    PubMed

    Richter, D; Fried, A; Wert, B P; Walega, J G; Tittel, F K

    2002-01-01

    The development of a compact tunable mid-IR laser system at 3.5 micrometers for quantitative airborne spectroscopic trace gas absorption measurements is reported. The mid-IR laser system is based on difference frequency generation (DFG) in periodically poled LiNbO3 and utilizes optical fiber amplified near-IR diode and fiber lasers as pump sources operating at 1083 nm and 1562 nm, respectively. This paper describes the optical sensor architecture, performance characteristics of individual pump lasers and DFG, as well as its application to wavelength modulation spectroscopy employing an astigmatic Herriott multi-pass gas absorption cell. This compact system permits detection of formaldehyde with a minimal detectable concentration (1 sigma replicate precision) of 74 parts-per-trillion by volume (pptv) for 1 min of averaging time and was achieved using calibrated gas standards, zero air background and rapid dual-beam subtraction. This corresponds to a pathlength-normalized replicate fractional absorption sensitivity of 2.5 x 10-(10 )cm-1. PMID:12599397

  6. Sensitivity of a tucuxi (Sotalia fluviatilis guianensis) to airborne sound

    NASA Astrophysics Data System (ADS)

    Liebschner, Alexander; Hanke, Wolf; Miersch, Lars; Dehnhardt, Guido; Sauerland, Matthias

    2005-01-01

    Auditory systems of cetaceans are considered highly specialized for underwater sound processing, whereas the extent of their hearing capacity in air is still a point of issue. In this study, the sensitivity to airborne sound in a male tucuxi (Sotalia fluviatilis guianensis) was tested by means of a go/no go response paradigm. Auditory thresholds were obtained from 2 to 31.5 kHz. Compared to the hearing thresholds of other dolphins as well as of amphibian mammals, the sensitivity to airborne sound of the test subject is low from 2 to 8 kHz, with the highest threshold at 4 kHz. Thresholds at 16 and 31.5 kHz reveal a sharp increase in hearing sensitivity. Thus, although not obtained in this study, the upper aerial hearing limit is in the ultrasonic range. A comparison of the present data with the underwater audiogram of the same test subject referred to sound intensity indicates that the sensitivity of Sotalia to underwater sound is generally better than to airborne sound. .

  7. β-(1,3)-Glucan Exposure Assessment by Passive Airborne Dust Sampling and New Sensitive Immunoassays▿

    PubMed Central

    Noss, Ilka; Wouters, Inge M.; Bezemer, Gillina; Metwali, Nervana; Sander, Ingrid; Raulf-Heimsoth, Monika; Heederik, Dick J. J.; Thorne, Peter S.; Doekes, Gert

    2010-01-01

    Associations between house dust-associated β-(1,3)-glucan exposure and airway inflammatory reactions have been reported, while such exposures in early childhood have been suggested to protect against asthma and wheezing. Most epidemiological studies have used reservoir dust samples and an inhibition enzyme immunoassay (EIA) for β-(1,3)-glucan exposure assessment. The objective of this study was to develop inexpensive but highly sensitive enzyme immunoassays to measure airborne β-(1,3)-glucans in low-exposure environments, like homes. Specificities of available anti-β-(1,3)-glucan antibodies were defined by direct and inhibition experiments. Three suitable antibody combinations were selected for sandwich EIAs. β-(1,3)-Glucans in passive airborne dust collected with an electrostatic dust fall collector (EDC) and floor dust from seven homes were measured with the three EIAs. Floor dust samples were additionally analyzed in the inhibition EIA. The sandwich EIAs were sensitive enough for airborne glucan measurement and showed different specificities for commercial glucans, while the β-(1,3)-glucan levels in house dust samples correlated strongly. The feasibility of measuring glucans in airborne dust with the recently introduced EDC method was further investigated by selecting the most suitable of the three EIAs to measure and compare β-(1,3)-glucan levels in the EDC and in floor and actively collected airborne dust samples of the previously performed EDC validation study. The EDC β-(1,3)-glucan levels correlated moderately with β-(1,3)-glucans in actively collected airborne dust and floor dust samples, while the glucan levels in the airborne dust and floor dust samples did not correlate. The combination of the newly developed β-(1,3)-glucan sandwich EIA with EDC sampling now allows assessment in large-scale population studies of exposure to airborne β-(1,3)-glucans in homes or other low-exposure environments. PMID:20038709

  8. High spectral resolution airborne short wave infrared hyperspectral imager

    NASA Astrophysics Data System (ADS)

    Wei, Liqing; Yuan, Liyin; Wang, Yueming; Zhuang, Xiaoqiong

    2016-05-01

    Short Wave InfraRed(SWIR) spectral imager is good at detecting difference between materials and penetrating fog and mist. High spectral resolution SWIR hyperspectral imager plays a key role in developing earth observing technology. Hyperspectral data cube can help band selections that is very important for multispectral imager design. Up to now, the spectral resolution of many SWIR hyperspectral imagers is about 10nm. A high sensitivity airborne SWIR hyperspectral imager with narrower spectral band will be presented. The system consists of TMA telescope, slit, spectrometer with planar blazed grating and high sensitivity MCT FPA. The spectral sampling interval is about 3nm. The IFOV is 0.5mrad. To eliminate the influence of the thermal background, a cold shield is designed in the dewar. The pixel number of spatial dimension is 640. Performance measurement in laboratory and image analysis for flight test will also be presented.

  9. High Resolution Airborne Shallow Water Mapping

    NASA Astrophysics Data System (ADS)

    Steinbacher, F.; Pfennigbauer, M.; Aufleger, M.; Ullrich, A.

    2012-07-01

    In order to meet the requirements of the European Water Framework Directive (EU-WFD), authorities face the problem of repeatedly performing area-wide surveying of all kinds of inland waters. Especially for mid-sized or small rivers this is a considerable challenge imposing insurmountable logistical efforts and costs. It is therefore investigated if large-scale surveying of a river system on an operational basis is feasible by employing airborne hydrographic laser scanning. In cooperation with the Bavarian Water Authority (WWA Weilheim) a pilot project was initiated by the Unit of Hydraulic Engineering at the University of Innsbruck and RIEGL Laser Measurement Systems exploiting the possibilities of a new LIDAR measurement system with high spatial resolution and high measurement rate to capture about 70 km of riverbed and foreland for the river Loisach in Bavaria/Germany and the estuary and parts of the shoreline (about 40km in length) of lake Ammersee. The entire area surveyed was referenced to classic terrestrial cross-section surveys with the aim to derive products for the monitoring and managing needs of the inland water bodies forced by the EU-WFD. The survey was performed in July 2011 by helicopter and airplane and took 3 days in total. In addition, high resolution areal images were taken to provide an optical reference, offering a wide range of possibilities on further research, monitoring, and managing responsibilities. The operating altitude was about 500 m to maintain eye-safety, even for the aided eye, the airspeed was about 55 kts for the helicopter and 75 kts for the aircraft. The helicopter was used in the alpine regions while the fixed wing aircraft was used in the plains and the urban area, using appropriate scan rates to receive evenly distributed point clouds. The resulting point density ranged from 10 to 25 points per square meter. By carefully selecting days with optimum water quality, satisfactory penetration down to the river bed was achieved

  10. Cost effective, weight sensitive design for military airborne electronic systems

    SciTech Connect

    Peck, W.M.

    1996-12-31

    Thermal management of Military airborne electronic systems is governed by many trade-offs. While the trade-offs may change depending on the customer and system requirements, minimizing weight is usually the primary engineering concern because it saves aircraft fuel. Fuel savings provides increased range and time aloft for the aircraft. The most common approach to achieving meaningful reductions in equipment weight is to reduce system volume. Reduced volume is achieved by increasing electronic packaging density which is accomplished by incorporating new materials, processes, and technologies into the system design. The following four considerations are currently under study in the development of an 8 KW high altitude Military electronic system in order to reduce system volume: (1) identifying design parameters and performing trade-off studies between the use of liquid vs. forced air for system cooling; (2) modeling the total system thermal resistance path to identify possible areas for reducing component temperature rise in order to provide enhanced system reliability; (3) substituting commercial plastic integrated circuits (ICs) for Mil ceramic components to reduce material cost while still meeting system requirements; and (4) using TC1050 material technology in: Militarizing Commercial Off The Shelf (COTS) Circuit Card Assemblies (CCAs), developing high conductivity ceramic packaging for Multi Chip Modules (MCMs), and for developing low coefficient of thermal expansion (CTE) composites for use at both the chip and chassis level. Current results from these studies have yielded a design that has a 2:1 reduction in system volume and a weight reduction of 480 lbs from a currently fielded system.

  11. NASA Langley Airborne High Spectral Resolution Lidar Instrument Description

    NASA Technical Reports Server (NTRS)

    Harper, David B.; Cook, Anthony; Hostetler, Chris; Hair, John W.; Mack, Terry L.

    2006-01-01

    NASA Langley Research Center (LaRC) recently developed the LaRC Airborne High Spectral Resolution Lidar (HSRL) to make measurements of aerosol and cloud distribution and optical properties. The Airborne HSRL has undergone as series of test flights and was successfully deployed on the Megacity Initiative: Local and Global Research Observations (MILAGRO) field mission in March 2006 (see Hair et al. in these proceedings). This paper provides an overview of the design of the Airborne HSRL and descriptions of some key subsystems unique to this instrument.

  12. Modeling Airborne Gravimetry with High-Degree Harmonic Expansions

    NASA Astrophysics Data System (ADS)

    Holmes, Simon; Wang, Yan Ming; Roman, Daniel

    2010-05-01

    Since its official unveiling at the 2008 General Assembly of the European Geosciences Union, EGM2008 has demonstrated that high-degree harmonic expansions constitute a useful and effective final representation for high-resolution global gravitational models. However, such expansions also provide a versatile means of capturing (modeling), inter-comparing, and optimally combining local and regional high-resolution terrestrial data sets of different types. Here we present a general recipe for using high-degree expansions to capture, downward-continue and assimilate airborne survey data. This approach relies on the production of two ‘competing' high-degree expansions. A first, ‘terrestrial-only' expansion incorporates EGM2008 globally, and high-resolution terrestrial gravimetry regionally. This expansion can be used to upward-continue the regional terrestrial data to the flight level of the airborne survey, such that the terrestrial gravimetry outside the survey area can be merged with the airborne data inside the survey area, all at flight level. Harmonic analysis of this merged data set, also at flight level, yields a second ‘airborne-augmented' expansion, which closely matches the ‘terrestrial-only' expansion outside the survey area, but which also closely reproduces the airborne survey data inside the survey area. Capturing the airborne and terrestrial data in this way means that downward-continuation of the airborne data, as well as spectral/spatial comparison (and ultimate combination) of the airborne data with the terrestrial (and satellite) data, can all be achieved through spherical- and ellipsoidal-harmonic synthesis of these two competing expansions, and their spectral combination. This general approach is illustrated with a worked example.

  13. First demonstration of a high performance difference frequency spectrometer on airborne platforms.

    PubMed

    Weibring, Petter; Richter, Dirk; Walega, James G; Fried, Alan

    2007-10-17

    We discuss the first airborne deployment and performance tests of a mid-IR difference frequency spectrometer system for highly sensitive measurements of formaldehyde. The laser system is based upon difference-frequency generation (DFG) at ~3.5 mum by mixing a DFB diode laser at 1562 nm and a distributed feedback (DFB) fiber laser at 1083 nm in a periodically poled LiNbO(3) (PPLN) crystal. Advanced LabVIEW software for lock-in, dual-beam optical noise subtraction, thermal control and active wavelength stabilization, renders a sensitivity of ~20 pptv (Absorbance ~7*10(-7)) for 30s of averaging. The instrument's performance characteristics spanning more than 300 flight hours during three consecutive airborne field missions MIRAGE, IMPEX and TexAQS operating on two airborne platforms, NCAR's C-130 and NOAA's P-3 aircraft are demonstrated. PMID:19550617

  14. Highly Protable Airborne Multispectral Imaging System

    NASA Technical Reports Server (NTRS)

    Lehnemann, Robert; Mcnamee, Todd

    2001-01-01

    A portable instrumentation system is described that includes and airborne and a ground-based subsytem. It can acquire multispectral image data over swaths of terrain ranging in width from about 1.5 to 1 km. The system was developed especially for use in coastal environments and is well suited for performing remote sensing and general environmental monitoring. It includes a small,munpilotaed, remotely controlled airplance that carries a forward-looking camera for navigation, three downward-looking monochrome video cameras for imaging terrain in three spectral bands, a video transmitter, and a Global Positioning System (GPS) reciever.

  15. Sensitivities of five alpha continuous air monitors for detection of airborne sup 239 Pu

    SciTech Connect

    McIsaac, C.V.; Amaro, C.R.

    1992-07-01

    Results of measurements of the sensitivities of five alpha continuous air monitors (CAMs) for detection of airborne {sup 239}Pu are presented. Four commercially available alpha CAMs (Kurz model 8311, Merlin Gerin Edgar, RADeCO model 452, and Victoreen model 758) and a prototype alpha CAM currently in use at Argonne National Laboratory- West (ANL-W) were tested sampling natural ambient air and laboratory-generated atmospheres laden with either blank dust or dust containing nCi/g concentrations of {sup 239}Pu. Cumulative alpha spectra were stored at 30 or 60 minute intervals during each sampling and were subsequently analyzed using three different commonly used alpha spectrum analysis algorithms. The effect of airborne dust concentration and sample filter porosity on detector resolution and sensitivity for airborne {sup 239}Pu are described.

  16. Sensitivities of five alpha continuous air monitors for detection of airborne {sup 239}Pu

    SciTech Connect

    McIsaac, C.V.; Amaro, C.R.

    1992-07-01

    Results of measurements of the sensitivities of five alpha continuous air monitors (CAMs) for detection of airborne {sup 239}Pu are presented. Four commercially available alpha CAMs (Kurz model 8311, Merlin Gerin Edgar, RADeCO model 452, and Victoreen model 758) and a prototype alpha CAM currently in use at Argonne National Laboratory- West (ANL-W) were tested sampling natural ambient air and laboratory-generated atmospheres laden with either blank dust or dust containing nCi/g concentrations of {sup 239}Pu. Cumulative alpha spectra were stored at 30 or 60 minute intervals during each sampling and were subsequently analyzed using three different commonly used alpha spectrum analysis algorithms. The effect of airborne dust concentration and sample filter porosity on detector resolution and sensitivity for airborne {sup 239}Pu are described.

  17. Airborne laser scanning for high-resolution mapping of Antarctica

    NASA Astrophysics Data System (ADS)

    Csatho, Bea; Schenk, Toni; Krabill, William; Wilson, Terry; Lyons, William; McKenzie, Garry; Hallam, Cheryl; Manizade, Serdar; Paulsen, Timothy

    In order to evaluate the potential of airborne laser scanning for topographic mapping in Antarctica and to establish calibration/validation sites for NASA's Ice, Cloud and land Elevation Satellite (ICESat) altimeter mission, NASA, the U.S. National Science Foundation (NSF), and the U.S. Geological Survey (USGS) joined forces to collect high-resolution airborne laser scanning data.In a two-week campaign during the 2001-2002 austral summer, NASA's Airborne Topographic Mapper (ATM) system was used to collect data over several sites in the McMurdo Sound area of Antarctica (Figure 1a). From the recorded signals, NASA computed laser points and The Ohio State University (OSU) completed the elaborate computation/verification of high-resolution Digital Elevation Models (DEMs) in 2003. This article reports about the DEM generation and some exemplary results from scientists using the geomorphologic information from the DEMs during the 2003-2004 field season.

  18. High-Sensitivity Spectrophotometry.

    ERIC Educational Resources Information Center

    Harris, T. D.

    1982-01-01

    Selected high-sensitivity spectrophotometric methods are examined, and comparisons are made of their relative strengths and weaknesses and the circumstances for which each can best be applied. Methods include long path cells, noise reduction, laser intracavity absorption, thermocouple calorimetry, photoacoustic methods, and thermo-optical methods.…

  19. High Speed Video for Airborne Instrumentation Application

    NASA Technical Reports Server (NTRS)

    Tseng, Ting; Reaves, Matthew; Mauldin, Kendall

    2006-01-01

    A flight-worthy high speed color video system has been developed. Extensive system development and ground and environmental. testing hes yielded a flight qualified High Speed Video System (HSVS), This HSVS was initially used on the F-15B #836 for the Lifting Insulating Foam Trajectory (LIFT) project.

  20. High-performance computing for airborne applications

    SciTech Connect

    Quinn, Heather M; Manuzzato, Andrea; Fairbanks, Tom; Dallmann, Nicholas; Desgeorges, Rose

    2010-06-28

    Recently, there has been attempts to move common satellite tasks to unmanned aerial vehicles (UAVs). UAVs are significantly cheaper to buy than satellites and easier to deploy on an as-needed basis. The more benign radiation environment also allows for an aggressive adoption of state-of-the-art commercial computational devices, which increases the amount of data that can be collected. There are a number of commercial computing devices currently available that are well-suited to high-performance computing. These devices range from specialized computational devices, such as field-programmable gate arrays (FPGAs) and digital signal processors (DSPs), to traditional computing platforms, such as microprocessors. Even though the radiation environment is relatively benign, these devices could be susceptible to single-event effects. In this paper, we will present radiation data for high-performance computing devices in a accelerated neutron environment. These devices include a multi-core digital signal processor, two field-programmable gate arrays, and a microprocessor. From these results, we found that all of these devices are suitable for many airplane environments without reliability problems.

  1. High Resolution Airborne Digital Imagery for Precision Agriculture

    NASA Technical Reports Server (NTRS)

    Herwitz, Stanley R.

    1998-01-01

    The Environmental Research Aircraft and Sensor Technology (ERAST) program is a NASA initiative that seeks to demonstrate the application of cost-effective aircraft and sensor technology to private commercial ventures. In 1997-98, a series of flight-demonstrations and image acquisition efforts were conducted over the Hawaiian Islands using a remotely-piloted solar- powered platform (Pathfinder) and a fixed-wing piloted aircraft (Navajo) equipped with a Kodak DCS450 CIR (color infrared) digital camera. As an ERAST Science Team Member, I defined a set of flight lines over the largest coffee plantation in Hawaii: the Kauai Coffee Company's 4,000 acre Koloa Estate. Past studies have demonstrated the applications of airborne digital imaging to agricultural management. Few studies have examined the usefulness of high resolution airborne multispectral imagery with 10 cm pixel sizes. The Kodak digital camera integrated with ERAST's Airborne Real Time Imaging System (ARTIS) which generated multiband CCD images consisting of 6 x 106 pixel elements. At the designated flight altitude of 1,000 feet over the coffee plantation, pixel size was 10 cm. The study involved the analysis of imagery acquired on 5 March 1998 for the detection of anomalous reflectance values and for the definition of spectral signatures as indicators of tree vigor and treatment effectiveness (e.g., drip irrigation; fertilizer application).

  2. Ultra-sensitive electrostatic planar acceleration gradiometer for airborne geophysical surveys

    NASA Astrophysics Data System (ADS)

    Douch, Karim; Christophe, Bruno; Foulon, Bernard; Panet, Isabelle; Pajot-Métivier, Gwendoline; Diament, Michel

    2014-10-01

    We propose a new concept of gravity gradiometer, GREMLIT, for the determination of the spatial derivatives of gravitational acceleration during airborne surveys. The core of this instrument is the acceleration gradiometer composed of four ultra-sensitive electrostatic planar accelerometers, inheriting from technologies developed for the GRACE and GOCE satellite gravity missions. Data from these missions have greatly improved our knowledge of the Earth’s gravity field and its time variations. However, resolving wavelengths of a few 10 km or less, beyond the reach of the satellite resolution, is of utmost importance to study a number of crustal geophysical processes and geological structures. We first present the benefits for a new gravity gradiometer, then we describe the planar acceleration gradiometer, which put together with three orthogonal gyroscopes, constitutes the gravity gradiometer GREMLIT. The acceleration gradiometer enables measurement at one point of the horizontal spatial derivatives of the acceleration horizontal components. We explain the measurement principle and describe the computation of the gravity gradients along with the necessary ancillary measurements. From a detailed error budget analysis of the accelerometers, an expected spectral sensitivity below \\text{1E/}\\sqrt{\\text{Hz}} is found in the [10-3, 0.2] Hz measurement bandwidth. To maintain such performance in flight, we finally discuss the adaptation of the acceleration gradiometer to the turbulent airborne environment. To limit the saturation of the accelerometers, we propose to cancel the common-mode output of the acceleration gradiometer by integrating the instrument on a double-gimbal platform controlled by the common-mode. We demonstrate on a real case study that with such a solution, it is technically possible to prevent the saturation of the accelerometers at least 95% of the time and it is not damaging to the airborne survey.

  3. Technology for the detection of airborne intruders approaching the high-security high-value asset

    NASA Astrophysics Data System (ADS)

    Greneker, Eugene F., III

    1995-05-01

    Security plans to protect high-value assets usually concentrate on stopping potential ground intruders before they reach the asset. Barriers, such as fences, are the first line of defense against the found intruder, providing a delay mechanism. The sight of 10 to 12 foot high fencing topped with razor wire, guard towers, and roving patrols also serves as a psychological deterrent to the potential ground intrusion sensors between an outer and an inner barrier. This visible 'hardness' of a high-value asset makes airborne penetration more attractive, even though the airborne intruder may require training in the use of an aircraft or other airborne conveyance system. Certain airborne intrusion scenarios allow an adversary to penetrate much deeper and faster through delay and defense systems designed to deter the ground intruder. Since an airborne intruder can quickly reach the high-value asset, early detection critical to asset defense. Early detection of the airborne intruder also ensures appropriate use of the deadly force doctrine because the guard force has time to coordinate the response.

  4. Stratospheric ozone isotopes observed by air-borne and space-borne submillimeter-wave heterodyne radiometry: A sensitivity study

    NASA Astrophysics Data System (ADS)

    Kasai, Y.; Urban, J.; Takahashi, C.; Smiles Mission Team

    2003-04-01

    The variation of the isotopic composition of a species in the Earth atmosphere provides us the information on the history of the air masses, because the isotope enrichment or depletion reflects the chemical and physical processes. Since the discovery of the heavy isotope enrichment of ozone in the stratosphere in 1981 considerable progress has been made in understanding the processes that control the isotope enrichment based on atmospheric observations, laboratory experiments, and so on. However, the exact mechanism for the effect remains uncertain and accurate sequentially observations of ozone isotopomer at global scale are still very sparse. Further improvements of measurement precision can be obtained by making use of the new technological development of high-precision submillimeter-wave heterodyne radiometry based on sensitive SIS detector technology. The airborne ASUR instrument (Airborne SUb-millimeter SIS Radiometer) observed lines of asymmetric-18 ozone in the frequency region of 645 GHz with this technology since ~1994. The JEM/SMILES instrument (Japaneses Experiment Module / Superconducting sub-MIllimeter Limb Emission Sounder), to be installed on the International Space Station in 2007, will measure several ozone isotopomer in the stratosphere at global scale from space using very similar frequency bands. An error analysis including the most typical systematic errors is performed.

  5. High resolution airborne geophysics at hazardous waste disposal sites

    SciTech Connect

    Beard, L.P.; Nyquist, J.E.; Doll, W.E.; Chong Foo, M.; Gamey, T.J.

    1995-06-01

    In 1994, a high resolution helicopter geophysical survey was conducted over portions of the Oak Ridge Reservation, Tennessee. The 1800 line kilometer survey included multi-frequency electromagnetic and magnetic sensors. The areas covered by the high resolution portion of the survey were selected on the basis of their importance to the environmental restoration effort and on data obtained from the reconnaissance phase of the airborne survey in which electromagnetic, magnetic, and radiometric data were collected over the entire Oak Ridge Reservation in 1992--1993. The high resolution phase had lower sensor heights, more and higher EM frequencies, and tighter line spacings than did the reconnaissance survey. When flying over exceptionally clear areas, the high resolution bird came within a few meters of the ground surface. Unfortunately, even sparse trees and power or phone lines could prevent the bird from being towed safely at low altitude, and over such areas it was more usual for it to be flown at about the same altitude as the bird in the reconnaissance survey, about 30m. Even so, the magnetometers used in the high resolution phase were 20m closer to the ground than in the reconnaissance phase because they were mounted on the tail of the bird rather than on the tow cable above the bird. The EM frequencies used in the high resolution survey ranged from 7400Hz to 67000Hz. Only the horizontal coplanar loop configuration was used in the high resolution flyovers.

  6. Kuiper Airborne Observatory's Telescope Stabilization System: Disturbance Sensitivity Reduction Via Velocity Loop Feedback

    NASA Technical Reports Server (NTRS)

    Lawrence, David P.; Tsui, K. C.; Tucker, John; Mancini, Ronald E. (Technical Monitor)

    1995-01-01

    In July of 1994 the Kuiper Airborne Observatory's (KAO) Telescope Stabilization System (TSS) was upgraded to meet performance goals necessary to view the Shoemaker-Levy 9 comet collision with Jupiter. The KAO is a modified C-141 Aircraft supporting a 36 inch Infrared telescope used to gather and analyze astronomical data. Before the upgrade, the TSS exhibited approximately a 10 arc-second resolution pointing accuracy. The majority of the inaccuracy was attributable to aircraft vibration and wind buffeting entering through the aircraft's telescope door opening; in other words, the TSS was overly sensitive to external disturbances. Because of power limitations and noise requirements, improving the pointing accuracy of the telescope required more sophistication than simply raising the bandwidth as some classical control strategies might suggest. Instead, relationships were developed between the disturbance sensitivity and closed loop transfer functions. These relationships suggested that employing velocity feedback along with an increase in current loop gain would dramatically improve the pointing resolution of the TSS by decreasing the control system's sensitivity to external disturbances. With the implementation of some classical control techniques and the above philosophy, the KAO's TSS's resolution was improved to approximately 2-3 arc-seconds.

  7. Selection of respiratory protection devices for use in very high concentrations of airborne plutonium.

    PubMed

    Bianconi, C J

    2000-08-01

    This paper focuses on the proper selection of respiratory protection devices for use in very high concentrations of airborne plutonium. Special attention is given to the determination of levels at which airborne plutonium presents a hazard that is immediately dangerous to life or health. PMID:10910403

  8. Benchmarking High Density Image Matching for Oblique Airborne Imagery

    NASA Astrophysics Data System (ADS)

    Cavegn, S.; Haala, N.; Nebiker, S.; Rothermel, M.; Tutzauer, P.

    2014-08-01

    Both, improvements in camera technology and new pixel-wise matching approaches triggered the further development of software tools for image based 3D reconstruction. Meanwhile research groups as well as commercial vendors provide photogrammetric software to generate dense, reliable and accurate 3D point clouds and Digital Surface Models (DSM) from highly overlapping aerial images. In order to evaluate the potential of these algorithms in view of the ongoing software developments, a suitable test bed is provided by the ISPRS/EuroSDR initiative Benchmark on High Density Image Matching for DSM Computation. This paper discusses the proposed test scenario to investigate the potential of dense matching approaches for 3D data capture from oblique airborne imagery. For this purpose, an oblique aerial image block captured at a GSD of 6 cm in the west of Zürich by a Leica RCD30 Oblique Penta camera is used. Within this paper, the potential test scenario is demonstrated using matching results from two software packages, Agisoft PhotoScan and SURE from University of Stuttgart. As oblique images are frequently used for data capture at building facades, 3D point clouds are mainly investigated at such areas. Reference data from terrestrial laser scanning is used to evaluate data quality from dense image matching for several facade patches with respect to accuracy, density and reliability.

  9. Airborne and Ground-Based Measurements Using a High-Performance Raman Lidar

    NASA Technical Reports Server (NTRS)

    Whiteman, David N.; Rush, Kurt; Rabenhorst, Scott; Welch, Wayne; Cadirola, Martin; McIntire, Gerry; Russo, Felicita; Adam, Mariana; Venable, Demetrius; Connell, Rasheen; Veselovskii, Igor; Forno, Ricardo; Mielke, Bernd; Stein, Bernhard; Leblanc, Thierry; McDermid, Stuart; Voemel, Holger

    2010-01-01

    A high-performance Raman lidar operating in the UV portion of the spectrum has been used to acquire, for the first time using a single lidar, simultaneous airborne profiles of the water vapor mixing ratio, aerosol backscatter, aerosol extinction, aerosol depolarization and research mode measurements of cloud liquid water, cloud droplet radius, and number density. The Raman Airborne Spectroscopic Lidar (RASL) system was installed in a Beechcraft King Air B200 aircraft and was flown over the mid-Atlantic United States during July August 2007 at altitudes ranging between 5 and 8 km. During these flights, despite suboptimal laser performance and subaperture use of the telescope, all RASL measurement expectations were met, except that of aerosol extinction. Following the Water Vapor Validation Experiment Satellite/Sondes (WAVES_2007) field campaign in the summer of 2007, RASL was installed in a mobile trailer for groundbased use during the Measurements of Humidity and Validation Experiment (MOHAVE-II) field campaign held during October 2007 at the Jet Propulsion Laboratory s Table Mountain Facility in southern California. This ground-based configuration of the lidar hardware is called Atmospheric Lidar for Validation, Interagency Collaboration and Education (ALVICE). During theMOHAVE-II field campaign, during which only nighttime measurements were made, ALVICE demonstrated significant sensitivity to lower-stratospheric water vapor. Numerical simulation and comparisons with a cryogenic frost-point hygrometer are used to demonstrate that a system with the performance characteristics of RASL ALVICE should indeed be able to quantify water vapor well into the lower stratosphere with extended averaging from an elevated location like Table Mountain. The same design considerations that optimize Raman lidar for airborne use on a small research aircraft are, therefore, shown to yield significant dividends in the quantification of lower-stratospheric water vapor. The MOHAVE

  10. Mangrove species mapping in Kuala Sepetang Mangrove Forest, Perak using high resolution airborne data

    NASA Astrophysics Data System (ADS)

    Beh, B. C.; MatJafri, M. Z.; Lim, H. S.

    2015-10-01

    Mangrove vegetation is widely employed and studied as it is a unique ecosystem which is able to provide plenty of goods and applications to our country. In this paper, high resolution airborne image data obtained the flight mission on Kuala Sepetang Mangrove Forest Reserve, Perak, Malaysia will be used for mangrove species mapping. Supervised classification using the retrieved surface reflectance will be performed to classify the airborne data using Geomatica 2013 software package. The ground truth data will be used to validate the classification accuracy. High correlation of R2=0.873 was achieved in this study indicate that high resolution airborne data is reliable and suitable used for mangrove species mapping.

  11. Simple method for measuring vibration amplitude of high power airborne ultrasonic transducer: using thermo-couple.

    PubMed

    Saffar, Saber; Abdullah, Amir

    2014-03-01

    Vibration amplitude of transducer's elements is the influential parameters in the performance of high power airborne ultrasonic transducers to control the optimum vibration without material yielding. The vibration amplitude of elements of provided high power airborne transducer was determined by measuring temperature of the provided high power airborne transducer transducer's elements. The results showed that simple thermocouples can be used both to measure the vibration amplitude of transducer's element and an indicator to power transmission to the air. To verify our approach, the power transmission to the air has been investigated by other common method experimentally. The experimental results displayed good agreement with presented approach. PMID:24246149

  12. High-Sensitivity Microwave Optics.

    ERIC Educational Resources Information Center

    Nunn, W. M., Jr.

    1981-01-01

    Describes a 3.33-cm wavelength (9 GHz) microwave system that achieves a high overall signal sensitivity and a well-collimated beam with moderate-size equipment. The system has been used to develop microwave versions of the Michelson interferometer, Bragg reflector, Brewster's law and total internal reflection, and Young's interference experiment.…

  13. Acute airway effects of airborne formaldehyde in sensitized and non-sensitized mice housed in a dry or humid environment

    SciTech Connect

    Larsen, Søren Thor Wolkoff, Peder Hammer, Maria Kofoed-Sørensen, Vivi Clausen, Per Axel Nielsen, Gunnar Damgård

    2013-05-01

    We investigated the role of air humidity and allergic sensitization on the acute airway response to inhaled formaldehyde (FA) vapor. Mice were sensitized to the immunogen ovalbumin (OVA) by three intraperitoneal injections followed by two aerosol challenges, giving rise to allergic airway inflammation. Control mice were sham sensitized by saline injections and challenged by saline aerosols. Once sensitized, the mice were housed at high (85–89%) or low (< 10%) relative humidity, respectively for 48 h prior to a 60-min exposure to either 0.4, 1.8 or about 5 ppm FA. Before, during and after exposure, breathing parameters were monitored. These included the specific markers of nose and lung irritations as well as the expiratory flow rate, the latter being a marker of airflow limitation. The sensory irritation response in the upper airways was not affected by allergic inflammation or changes in humidity. At high relative humidity, the OVA-sensitized mice had a decreased expiratory airflow rate compared to the saline control mice after exposure to approximately 5 ppm FA. This is in accordance with the observations that asthmatics are more sensitive than non-asthmatics to higher concentrations of airway irritants including FA. In the dry environment, the opposite trend was seen; here, the saline control mice had a significantly decreased expiratory airflow rate compared to OVA-sensitized mice when exposed to 1.8 and 4 ppm FA. We speculate that increased mucus production in the OVA-sensitized mice has increased the “scrubber effect” in the nose, consequently protecting the conducting and lower airways. - Highlights: ► Role of air humidity and allergy on sensitivity to an airway irritant was studied. ► In the humid environment, allergy amplified the effects of formaldehyde. ► In the dry environment, allergy reduced the effect of formaldehyde. ► Neither allergy nor humidity changed the formaldehyde-induced nasal irritation.

  14. High-Accuracy Elevation Data at Large Scales from Airborne Single-Pass SAR Interferometry

    NASA Astrophysics Data System (ADS)

    Schumann, Guy; Moller, Delwyn; Mentgen, Felix

    2015-12-01

    Digital elevation models (DEMs) are essential data sets for disaster risk management and humanitarian relief services as well as many environmental process models. At present, on the hand, globally available DEMs only meet the basic requirements and for many services and modeling studies are not of high enough spatial resolution and lack accuracy in the vertical. On the other hand, LiDAR-DEMs are of very high spatial resolution and great vertical accuracy but acquisition operations can be very costly for spatial scales larger than a couple of hundred square km and also have severe limitations in wetland areas and under cloudy and rainy conditions. The ideal situation would thus be to have a DEM technology that allows larger spatial coverage than LiDAR but without compromising resolution and vertical accuracy and still performing under some adverse weather conditions and at a reasonable cost. In this paper, we present a novel single pass In-SAR technology for airborne vehicles that is cost-effective and can generate DEMs with a vertical error of around 0.3 m for an average spatial resolution of 3 m. To demonstrate this capability, we compare a sample single-pass In-SAR Ka-band DEM of the California Central Valley from the NASA/JPL airborne GLISTIN-A to a high-resolution LiDAR DEM. We also perform a simple sensitivity analysis to floodplain inundation. Based on the findings of our analysis, we argue that this type of technology can and should be used to replace large regions of globally available lower resolution DEMs, particularly in coastal, delta and floodplain areas where a high number of assets, habitats and lives are at risk from natural disasters. We conclude with a discussion on requirements, advantages and caveats in terms of instrument and data processing.

  15. High-resolution Profiling of the Lower Troposphere from Airborne GPS Radio Occultation

    NASA Astrophysics Data System (ADS)

    Adhikari, L.; Murphy, B.; Xie, F.; Haase, J. S.; Muradyan, P.; Wang, K.; Garrison, J. L.

    2013-12-01

    The Airborne GPS radio occultation (RO) technique offers dense sounding measurements over a target region in all-weather conditions that is very attractive for regional atmospheric process studies. During the PRE-Depression Investigation of Cloud-systems in the Tropics (PREDICT) field campaign in 2010, numerous airborne RO soundings were collected by Global Navigation Satellite Systems (GNSS) Instrument System for Multistatic and Occultation Sensing (GISMOS) aboard the NCAR Gulfstream-V aircraft. The atmospheric refractivity and bending angle profiles have been successfully retrieved with a geometric optics (GO) method. However, the multipath phenomena caused by the large variation of water vapor in the lower troposphere limits the application of GO method and stresses the need for radio-holographic methods. In this study, the full-spectrum-inversion (FSI) method that is widely used for spaceborne RO retrieval is adapted to account for the airborne RO geometry with an RO receiver inside the atmosphere. A sensitivity analysis of the FSI method based on simulated airborne RO signals will be shown. Preliminary results of the FSI bending angle and refractivity retrieval from the PREDICT airborne RO measurements will also be presented and compared with the GO retrieval as well as the near-coincident model analysis and in-situ balloon soundings.

  16. Airborne and Ground-Based Measurements Using a High-Performance Raman Lidar. Part 2; Ground Based

    NASA Technical Reports Server (NTRS)

    Whiteman, David N.; Cadirola, Martin; Venable, Demetrius; Connell, Rasheen; Rush, Kurt; Leblanc, Thierry; McDermid, Stuart

    2009-01-01

    The same RASL hardware as described in part I was installed in a ground-based mobile trailer and used in a water vapor lidar intercomparison campaign, hosted at Table Mountain, CA, under the auspices of the Network for the Detection of Atmospheric Composition Change (NDACC). The converted RASL hardware demonstrated high sensitivity to lower stratospheric water vapor indicating that profiling water vapor at those altitudes with sufficient accuracy to monitor climate change is possible. The measurements from Table Mountain also were used to explain the reason, and correct , for sub-optimal airborne aerosol extinction performance during the flight campaign.

  17. High-Rate Wireless Airborne Network Demonstration (HiWAND) Flight Test Results

    NASA Technical Reports Server (NTRS)

    Franz, Russell

    2008-01-01

    An increasing number of flight research and airborne science experiments now contain network-ready systems that could benefit from a high-rate bidirectional air-to-ground network link. A prototype system, the High-Rate Wireless Airborne Network Demonstration, was developed from commercial off-the-shelf components while leveraging the existing telemetry infrastructure on the Western Aeronautical Test Range. This approach resulted in a cost-effective, long-range, line-of-sight network link over the S and the L frequency bands using both frequency modulation and shaped-offset quadrature phase-shift keying modulation. This report discusses system configuration and the flight test results.

  18. High-Rate Wireless Airborne Network Demonstration (HiWAND) Flight Test Results

    NASA Technical Reports Server (NTRS)

    Franz, Russell

    2007-01-01

    An increasing number of flight research and airborne science experiments now contain network-ready systems that could benefit from a high-rate bidirectional air-to-ground network link. A prototype system, the High-Rate Wireless Airborne Network Demonstration, was developed from commercial off-the-shelf components while leveraging the existing telemetry infrastructure on the Western Aeronautical Test Range. This approach resulted in a cost-effective, long-range, line-of-sight network link over the S and the L frequency bands using both frequency modulation and shaped-offset quadrature phase-shift keying modulation. This paper discusses system configuration and the flight test results.

  19. An infrared high resolution silicon immersion grating spectrometer for airborne and space missions

    NASA Astrophysics Data System (ADS)

    Ge, Jian; Zhao, Bo; Powell, Scott; Jiang, Peng; Uzakbaiuly, Berik; Tanner, David

    2014-08-01

    Broad-band infrared (IR) spectroscopy, especially at high spectral resolution, is a largely unexplored area for the far IR (FIR) and submm wavelength region due to the lack of proper grating technology to produce high resolution within the very constrained volume and weight required for space mission instruments. High resolution FIR spectroscopy is an essential tool to resolve many atomic and molecular lines to measure physical and chemical conditions and processes in the environments where galaxy, star and planets form. A silicon immersion grating (SIG), due to its over three times high dispersion over a traditional reflective grating, offers a compact and low cost design of new generation IR high resolution spectrographs for space missions. A prototype SIG high resolution spectrograph, called Florida IR Silicon immersion grating spectromeTer (FIRST), has been developed at UF and was commissioned at a 2 meter robotic telescope at Fairborn Observatory in Arizona. The SIG with 54.74 degree blaze angle, 16.1 l/mm groove density, and 50x86 mm2 grating area has produced R=50,000 in FIRST. The 1.4-1.8 um wavelength region is completely covered in a single exposure with a 2kx2k H2RG IR array. The on-sky performance meets the science requirements for ground-based high resolution spectroscopy. Further studies show that this kind of SIG spectrometer with an airborne 2m class telescope such as SOFIA can offer highly sensitive spectroscopy with R~20,000-30,000 at 20 to 55 microns. Details about the on-sky measurement performance of the FIRST prototype SIG spectrometer and its predicted performance with the SOFIA 2.4m telescope are introduced.

  20. A high sensitivity THz detector

    NASA Astrophysics Data System (ADS)

    Su, Bo; Duan, Guoteng

    2011-08-01

    We have developed a novel THz detector which uses the cantilever technology and surface plasmon resonance (SPR) technology to achieve a high sensitivity. The Micro Electro Mechanical System (MEMS) technology is adopted to fabricate the detector, which comprise thermo-sensitive bi-material micro-cantilever, prism and optical readout system. The bi-material of Si3N4 and Al is used to fabricate the micro-cantilever because of the good absorption characteristic for THz of Si3N4 and the great difference in thermal expansion coefficient of the bi-material for the deformation of the micro-cantilever. In order to increase the deformation of micro-cantilever, the method of computer simulation is used to obtain the optimal structure of micro-cantilever and the thickness of Si3N4 and Al. The function of the glass prism is to make the incident light generate total reflection under certain conditions. The gold film is sputtering on the top of glass slide using the method of magnetron sputtering and it is necessary for the generation of SPR performance. The optical readout system can make the change of cantilever bending convert to the change of reflection luminous intensity proportionally. The heat on the micro-cantilever coming from the THz radiation can lose easily in the air, so the detector is placed vertically in a cylindrical vacuum chamber which is sealed with quartz glasses and polyethylene lamina at the two end surfaces respectively. The quartz glass is used for the incidence of visible polarized light and the polyethylene lamina for the THz radiation. In order to maintain the vacuum performance of the chamber, the mechanical pump and molecular pump are adopted. In static mode, THz radiation absorption raises the temperature of micro-cantilever, so it bends proportionally. The micro-cantilever bending changes the thicknesses of the gap between the micro-cantilever and the metallic thin film on the micro-prism. It will result in a shift of the SPR angle. Therefore, the

  1. High resolution Michelson interferometer for airborne infrared astronomical observations. 2: System design.

    PubMed

    Langlet, A; Delage, C; Stefanovitch, D; Talureau, B; Tualy, J; Verveer, J; Fischer, W P; Gilles, J M; Scheper, R; Leblanc, J; Dambier, G

    1977-07-01

    A Michelson interferometer for high resolution (lambda/Deltalambda approximately 10(4)) spectroscopic observations of astronomical ir ionic line emission has been built and flown on the NASA 91-cm airborne ir telescope facility (G. P. Kuiper Airborne Observatory). In Part 1 of this paper the requirements for such a system were outlined, and the scientific basis for the choice of instrumental parameters and the rapid scan mode of operation were discussed. In this paper design details of the instrument are presented. These include the optics, control He-Ne laser interferometer, helium-cooled bolometer detector, and cooled passband filters. In addition, the on-line computer software which enables the operator to interact rapidly with the system to produce inflight spectra and control accordingly the observational parameters is described, as are elements of the electronics hardware developed specially for airborne observations. PMID:20168820

  2. Sterilizing Effects of High-Intensity Airborne Sonic and Ultrasonic Waves

    PubMed Central

    Pisano, Michael A.; Boucher, Raymond M. G.; Alcamo, I. Edward

    1966-01-01

    The lethal effects of high-intensity airborne sonic (9.9 kc/sec) and ultrasonic waves (30.4 kc/sec) on spores of Bacillus subtilis var. niger ATCC 9372 were determined. The spores, which were deposited on filter-paper strips, were exposed to sound waves for periods varying from 1 to 8 hr, at a temperature of 40 C and a relative humidity of 40%. Significant reductions in the viable counts of spores exposed to airborne sonic or ultrasonic irradiations were obtained. The antibacterial activity of airborne sound waves varied with the sound intensity level, the period of irradiation, and the distance of the sample from the sound source. At similar intensity levels, the amplitude of motion of the sound waves appeared to be a factor in acoustic sterilization. Images Fig. 1 PMID:4961527

  3. Sensitivity of airborne fluorosensor measurements to linear vertical gradients in chlorophyll concentration

    NASA Technical Reports Server (NTRS)

    Venable, D. D.; Punjabi, A. R.; Poole, L. R.

    1984-01-01

    A semianalytic Monte Carlo radiative transfer simulation model for airborne laser fluorosensors has been extended to investigate the effects of inhomogeneities in the vertical distribution of phytoplankton concentrations in clear seawater. Simulation results for linearly varying step concentrations of chlorophyll are presented. The results indicate that statistically significant differences can be seen under certain conditions in the water Raman-normalized fluorescence signals between nonhomogeneous and homogeneous cases. A statistical test has been used to establish ranges of surface concentrations and/or verticl gradients in which calibration by surface samples would by inappropriate, and the results are discussed.

  4. Lysimetric evaluation of SEBAL using high resolution airborne imagery from BEAREX08

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study, the SEBAL was evaluated for its ability to derive aerodynamic components and surface energy fluxes from high resolution airborne remote sensing data acquired during the Bushland Evapotranspiration and Agricultural Remote Sensing Experiment 2008 in Texas, USA. Issues related to hot and...

  5. A high-resolution airborne four-camera imaging system for agricultural remote sensing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper describes the design and testing of an airborne multispectral digital imaging system for remote sensing applications. The system consists of four high resolution charge coupled device (CCD) digital cameras and a ruggedized PC equipped with a frame grabber and image acquisition software. T...

  6. Potential Use of CW High Energy Laser on an Airborne Platform

    NASA Astrophysics Data System (ADS)

    Cook, Joung R.; Cusumano, Salvatore J.; Whiteley, Mathew R.

    2006-05-01

    Beamed energy propulsion (BEP) offers advanced and intellectually satisfying options to a class of space applications by using a high energy laser (HEL) as the prime power that is external to the system being propelled. Included in this class of applications are: launching satellites into orbit, space debris clearing, and orbital maneuvering, among others. Realistic applications or demonstrations of such BEP applications have been limited by the availability of HEL devices ever since the concept was first suggested by Arthur Kantrowitz in 1972. Development of the devices needed for BEP has been slow due to technology challenges and the significant non-recurring engineering costs. In general HEL systems of viable power levels have been exclusively the domain of military research and development. With the recent investment in the airborne platform laser systems, it may now be possible to capitalize on the military successes of such a system. The next decade may hold the possibility of transitioning defense HEL technology into BEP. The transitioning of military technology into civilian applications has occurred many times in the past, so speculation on available sources for BEP is not completely without merit. The concept of an airborne platform for BEP offers mobility and mitigates the coherence, reducing atmospheric turbulence. Operating at 12 kilometers (km), an airborne platform significantly reduces the beam path issues associated with ground to space. The trade-off is that the airborne platform disturbances are much greater and require more creative stabilization solutions than one sitting on "Terra Firma." The use of jitter reduction techniques may provide a profitable compromise for an airborne versus a ground-based system for BEP. This paper concentrates on the potential benefits from the use of an airborne platform for the BEP community.

  7. Size resolved airborne particulate polysaccharides in summer high Arctic

    NASA Astrophysics Data System (ADS)

    Leck, C.; Gao, Q.; Mashayekhy Rad, F.; Nilsson, U.

    2013-04-01

    Size-resolved aerosol samples for subsequent determination of polysaccharides (monosaccharides in combined form) were collected in air over the central Arctic Ocean during the biologically most active period between the late summer melt season and into the transition to autumn freeze-up. The analysis was carried out using liquid chromatography coupled with highly selective and sensitive tandem mass spectrometry. Polysaccharides were detected in all sizes ranging from 0.035 to 10 μm in diameter with distinct features of heteropolysaccharides, enriched in xylose, glucose + mannose as well as a substantial fraction of deoxysugars. Polysaccharides containing deoxysugars showed a bimodal structure with about 60% of their mass found in the Aitken mode over the pack ice area. Pentose (xylose) and hexose (glucose + mannose) showed a weaker bimodal character and were largely found in the coarse mode in addition to a minor fraction apportioned in the sub-micrometer size range. The concentration of total hydrolysable neutral sugars (THNS) in the samples collected varied over 3 orders of magnitude (1 to 692 pmol m-3) in the super-micrometer size fraction and to a lesser extent in sub-micrometer particles (4 to 88 pmol m-3). Lowest THNS concentrations were observed in air masses that had spent more than 5 days over the pack ice. Within the pack ice area, about 53% (by mass) of the total mass of polysaccharides were found in sub-micrometer particles. The relative abundance of sub-micrometer polysaccharides was closely related to the length of time that the air mass spent over pack ice, with highest fraction (> 90%) observed for > 7 days of advection. The ambient aerosol particles collected onboard ship showed similar monosaccharide composition, compared to particles generated experimentally in situ at the open lead site. This supports the existence of a primary source of particulate polysaccharides from open leads by bubble bursting at the air-sea interface. We speculate that

  8. Highly thermostable anatase titania-pillared clay for the photocatalytic degradation of airborne styrene.

    PubMed

    Lim, Melvin; Zhou, Yan; Wood, Barry; Wang, Lian Zhou; Rudolph, Victor; Lu, Gao Qing

    2009-01-15

    Airborne styrene is a suspected human carcinogen, and traditional ways of mitigation include the use of adsorption technologies (activated carbon or zeolites) or thermal destruction. These methods presenttheir own shortcomings, i.e., adsorbents need to be regenerated or replaced regularly, and relatively large energy inputs are required in thermal treatment. Photocatalysis offers a potentially sustainable and clean means of controlling such fugitive emissions of styrene in air. The present study demonstrates a new type of well-characterized, highly thermostable titania-pillared clay photocatalysts for airborne styrene decomposition in a custom-designed fluidized-bed photoreactor. This photocatalytic system is found to be capable of destroying up to 87% of 300 ppmV airborne styrene in the presence of ultraviolet (UV) irradiation. The effects of relative humidity (RH: 0 or 20%) are also studied, together with the arising physical structures (in terms of porosity and surface characteristics) of the catalysts when subjected to relatively high calcination temperatures of 1000-1200 degrees C. Such a temperature range may be encountered, e.g., in flue gas emissions (1). It is found that relative humidity levels of 20% retard the degradation efficiencies of airborne styrene when using highly porous catalysts. PMID:19238991

  9. Direct Analysis of Low-Volatile Molecular Marker Extract from Airborne Particulate Matter Using Sensitivity Correction Method

    PubMed Central

    Irei, Satoshi

    2016-01-01

    Molecular marker analysis of environmental samples often requires time consuming preseparation steps. Here, analysis of low-volatile nonpolar molecular markers (5-6 ring polycyclic aromatic hydrocarbons or PAHs, hopanoids, and n-alkanes) without the preseparation procedure is presented. Analysis of artificial sample extracts was directly conducted by gas chromatography-mass spectrometry (GC-MS). After every sample injection, a standard mixture was also analyzed to make a correction on the variation of instrumental sensitivity caused by the unfavorable matrix contained in the extract. The method was further validated for the PAHs using the NIST standard reference materials (SRMs) and then applied to airborne particulate matter samples. Tests with the SRMs showed that overall our methodology was validated with the uncertainty of ~30%. The measurement results of airborne particulate matter (PM) filter samples showed a strong correlation between the PAHs, implying the contributions from the same emission source. Analysis of size-segregated PM filter samples showed that their size distributions were found to be in the PM smaller than 0.4 μm aerodynamic diameter. The observations were consistent with our expectation of their possible sources. Thus, the method was found to be useful for molecular marker studies. PMID:27127511

  10. High Energy 2-Micron Solid-State Laser Transmitter for NASA's Airborne CO2 Measurements

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta; Bai, Yingxin

    2012-01-01

    A 2-micron pulsed, Integrated Path Differential Absorption (IPDA) lidar instrument for ground and airborne atmospheric CO2 concentration measurements via direct detection method is being developed at NASA Langley Research Center. This instrument will provide an alternate approach to measure atmospheric CO2 concentrations with significant advantages. A high energy pulsed approach provides high-precision measurement capability by having high signal-to-noise level and unambiguously eliminates the contamination from aerosols and clouds that can bias the IPDA measurement.

  11. Similarity and Complementarity of Airborne and Terrestrial LiDAR Data in High Mountain Regions

    NASA Astrophysics Data System (ADS)

    Kamp, Nicole; Glira, Philipp; Pfeifer, Norbert

    2013-04-01

    Glacier melt and a consequential increased sediment transport (erosion, transportation and accumulation) in high mountain regions are causing a frequent occurrence of geomorphic processes such as landslides and other natural hazards. These effects are investigated at the Gepatschferner (Kaunertal, Oetztal Alps, Tyrol), the second largest glacier in Austria, in the PROSA project (Catholic University Eichstätt - Ingolstadt, Vienna University of Technology, Friedrich Alexander University Erlangen-Nürnberg, Martin-Luther-University Halle-Wittenberg, University of Innsbruck, Munich University of Technology). To monitor these geomorphic processes, data with a very high spatial and very high temporally accuracy and resolution are needed. For this purpose multi-temporal terrestrial and aerial laser scanning data are acquired, processed and analysed. Airborne LiDAR data are collected with a density of 10 points/m² over the whole study area of the glacier and its foreland. Terrestrial LiDAR data are gathered to complement and improve the airborne LiDAR data. The different viewing geometry results in differences between airborne and terrestrial data. Very steep slopes and rock faces (around 90°, depending on the viewing direction) are not visible from the airborne view point. On the other hand, terrestrial viewpoints exhibit shadows for areas above the scanner position and in viewing direction behind vertical or steep faces. In addition, the density of terrestrial data is varying strongly, but has for most of the covered area a much higher level of detail than the airborne dataset. A small temporal baseline is also inevitable and may cause differences between acquisition of airborne and terrestrial data. The goal of this research work is to develop a method for merging airborne and terrestrial LiDAR data. One prerequisite for merging is the identification of areas which are measurements of the same physical surface in either data set. This allows a transformation of the

  12. High-sensitivity nanosensors for biomarker detection†

    PubMed Central

    Swierczewska, Magdalena; Liu, Gang

    2013-01-01

    High sensitivity nanosensors utilize optical, mechanical, electrical, and magnetic relaxation properties to push detection limits of biomarkers below previously possible concentrations. The unique properties of nanomaterials and nanotechnology are exploited to design biomarker diagnostics. High-sensitivity recognition is achieved by signal and target amplification along with thorough pre-processing of samples. In this tutorial review, we introduce the type of detection signals read by nanosensors to detect extremely small concentrations of biomarkers and provide distinctive examples of high-sensitivity sensors. The use of such high-sensitivity nanosensors can offer earlier detection of disease than currently available to patients and create significant improvements in clinical outcomes. PMID:22187721

  13. Fast, high sensitivity dewpoint hygrometer

    NASA Technical Reports Server (NTRS)

    Hoenk, Michael E. (Inventor)

    1998-01-01

    A dewpoint/frostpoint hygrometer that uses a surface moisture-sensitive sensor as part of an RF oscillator circuit with feedback control of the sensor temperature to maintain equilibrium at the sensor surface between ambient water vapor and condensed water/ice. The invention is preferably implemented using a surface acoustic wave (SAW) device in an RF oscillator circuit configured to generate a condensation-dependent output signal, a temperature sensor to measure the temperature of the SAW device and to distinguish between condensation-dependent and temperature-dependent signals, a temperature regulating device to control the temperature of the SAW device, and a feedback control system configured to keep the condensation-dependent signal nearly constant over time in the presence of time-varying humidity, corrected for temperature. The effect of this response is to heat or cool the surface moisture-sensitive device, which shifts the equilibrium with respect to evaporation and condensation at the surface of the device. The equilibrium temperature under feedback control is a measure of dewpoint or frostpoint.

  14. Application of high intensity air-borne ultrasound for debubbling liquid coating layers.

    PubMed

    González, I; Rodríguez, J; Garmendia, I; Gallego-Juárez, J A

    2006-12-22

    In the coating processes, the formation of bubbles and microbubbles is relatively frequent inside the coating layer. Such bubbles, which are formed as a consequence of air retention, are difficult to remove and specifically in high-speed (quick-drying) industrial application where they cause permanent imperfections in the homogeneity of the layer. High-intensity air-borne ultrasound may represent a clean means to improve homogenization by quickly breaking the bubbles just when they are formed inside the coating film. This paper deals with the direct application of air-borne high-intensity ultrasonic radiation at a frequency of about 21 kHz over coating layers just immediately they have been deposited over wood substrates. Such novel process has been implemented and experimentally studied at laboratory and semi-industrial stages. PMID:16797638

  15. Cryogenic High-Sensitivity Magnetometer

    NASA Technical Reports Server (NTRS)

    Day, Peter; Chui, Talso; Goodstein, David

    2005-01-01

    A proposed magnetometer for use in a cryogenic environment would be sensitive enough to measure a magnetic-flux density as small as a picogauss (10(exp -16) Tesla). In contrast, a typical conventional flux-gate magnetometer cannot measure a magnetic-flux density smaller that about 1 microgauss (10(exp -10) Tesla). One version of this device, for operation near the low end of the cryogenic temperature range, would include a piece of a paramagnetic material on a platform, the temperature of which would be controlled with a periodic variation. The variation in temperature would be measured by use of a conventional germanium resistance thermometer. A superconducting coil would be wound around the paramagnetic material and coupled to a superconducting quantum interference device (SQUID) magnetometer.

  16. Nano-textured high sensitivity ion sensitive field effect transistors

    NASA Astrophysics Data System (ADS)

    Hajmirzaheydarali, M.; Sadeghipari, M.; Akbari, M.; Shahsafi, A.; Mohajerzadeh, S.

    2016-02-01

    Nano-textured gate engineered ion sensitive field effect transistors (ISFETs), suitable for high sensitivity pH sensors, have been realized. Utilizing a mask-less deep reactive ion etching results in ultra-fine poly-Si features on the gate of ISFET devices where spacing of the order of 10 nm and less is achieved. Incorporation of these nano-sized features on the gate is responsible for high sensitivities up to 400 mV/pH in contrast to conventional planar structures. The fabrication process for this transistor is inexpensive, and it is fully compatible with standard complementary metal oxide semiconductor fabrication procedure. A theoretical modeling has also been presented to predict the extension of the diffuse layer into the electrolyte solution for highly featured structures and to correlate this extension with the high sensitivity of the device. The observed ultra-fine features by means of scanning electron microscopy and transmission electron microscopy tools corroborate the theoretical prediction.

  17. Viability and potential for immigration of airborne bacteria from Africa that reach high mountain lakes in Europe.

    PubMed

    Hervàs, Anna; Camarero, Lluís; Reche, Isabel; Casamayor, Emilio O

    2009-06-01

    We have analysed the diversity of the bacteria, which grow after addition of concentrated airborne particles and desert dust in different microcosms combinations with water samples from oligotrophic alpine lakes. We used, on the one hand, airborne bacteria transported by an African dust plume and collected in a high mountain area in the central Pyrenees (Spain). On the other hand, we collected desert dust in Mauritania (c. 3000 km distance, and a few days estimated airborne journey), a known source region for dust storms in West Africa, which originates many of the dust plumes landing on Europe. In all the dust-amended treatments we consistently observed bacterial growth of common phyla usually found in freshwater ecosystems, i.e. Alpha-, Beta- and Gammaproteobacteria, Actinobacteria, and a few Bacteroidetes, but with different composition based on lake water pretreatment and dust type. Overall, we tentatively split the bacterial community in (i) typical freshwater non-airborne bacteria, (ii) cosmopolitan long-distance airborne bacteria, (iii) non-freshwater low-distance airborne bacteria, (iv) non-freshwater long-distance airborne soil bacteria and (v) freshwater non-soil airborne bacteria. We identified viable long-distance airborne bacteria as immigrants in alpine lakes (e.g. Sphingomonas-like) but also viable putative airborne pathogens with the potential to grow in remote alpine areas (Acinetobacter-like and Arthrobacter-like). Generation of atmospheric aerosols and remote dust deposition is a global process, largely enhanced by perturbations linked to the global change, and high mountain lakes are very convenient worldwide model systems for monitoring global-scale bacterial dispersion and pathogens entries in remote pristine environments. PMID:19453609

  18. Use of a new high-speed digital data acquisition system in airborne ice-sounding

    USGS Publications Warehouse

    Wright, David L.; Bradley, Jerry A.; Hodge, Steven M.

    1989-01-01

    A high-speed digital data acquisition and signal averaging system for borehole, surface, and airborne radio-frequency geophysical measurements was designed and built by the US Geological Survey. The system permits signal averaging at rates high enough to achieve significant signal-to-noise enhancement in profiling, even in airborne applications. The first field use of the system took place in Greenland in 1987 for recording data on a 150 by 150-km grid centered on the summit of the Greenland ice sheet. About 6000-line km were flown and recorded using the new system. The data can be used to aid in siting a proposed scientific corehole through the ice sheet.

  19. Airborne high spectral resolution lidar for measuring aerosol extinction and backscatter coefficients.

    PubMed

    Esselborn, Michael; Wirth, Martin; Fix, Andreas; Tesche, Matthias; Ehret, Gerhard

    2008-01-20

    An airborne high spectral resolution lidar (HSRL) based on an iodine absorption filter and a high-power frequency-doubled Nd:YAG laser has been developed to measure backscatter and extinction coefficients of aerosols and clouds. The instrument was operated aboard the Falcon 20 research aircraft of the German Aerospace Center (DLR) during the Saharan Mineral Dust Experiment in May-June 2006 to measure optical properties of Saharan dust. A detailed description of the lidar system, the analysis of its data products, and measurements of backscatter and extinction coefficients of Saharan dust are presented. The system errors are discussed and airborne HSRL results are compared to ground-based Raman lidar and sunphotometer measurements. PMID:18204721

  20. Airborne Transmission of Highly Pathogenic H7N1 Influenza Virus in Ferrets

    PubMed Central

    Finch, Courtney; Shao, Hongxia; Angel, Matthew; Chen, Hongjun; Capua, Ilaria; Cattoli, Giovanni; Monne, Isabella

    2014-01-01

    ABSTRACT Avian H7 influenza viruses are recognized as potential pandemic viruses, as personnel often become infected during poultry outbreaks. H7 infections in humans typically cause mild conjunctivitis; however, the H7N9 outbreak in the spring of 2013 has resulted in severe respiratory disease. To date, no H7 viruses have acquired the ability for sustained transmission among humans. Airborne transmission is considered a requirement for the emergence of pandemic influenza, and advanced knowledge of the molecular changes or signature required for transmission would allow early identification of pandemic vaccine seed stocks, screening and stockpiling of antiviral compounds, and eradication efforts focused on flocks harboring threatening viruses. Thus, we sought to determine if a highly pathogenic influenza A H7N1 (A/H7N1) virus with no history of human infection could become capable of airborne transmission among ferrets. We show that after 10 serial passages, A/H7N1 developed the ability to be transmitted to cohoused and airborne contact ferrets. Four amino acid mutations (PB2 T81I, NP V284M, and M1 R95K and Q211K) in the internal genes and a minimal amino acid mutation (K/R313R) in the stalk region of the hemagglutinin protein were associated with airborne transmission. Furthermore, transmission was not associated with loss of virulence. These findings highlight the importance of the internal genes in host adaptation and suggest that natural isolates carrying these mutations be further evaluated. Our results demonstrate that a highly pathogenic avian H7 virus can become capable of airborne transmission in a mammalian host, and they support ongoing surveillance and pandemic H7 vaccine development. IMPORTANCE The major findings of this report are that a highly pathogenic strain of H7N1 avian influenza virus can be adapted to become capable of airborne transmission in mammals without mutations altering receptor specificity. Changes in receptor specificity have been

  1. Novel Airborne Imaging Polarimeter Undergoes High-Altitude Flight Testing

    NASA Technical Reports Server (NTRS)

    Diner, David J.; Pingree, Paula J.; Chipman, Russell A.

    2015-01-01

    Optical and signal processing technologies for high-accuracy polarimetric imaging, aimed at studying the impact of atmospheric haze and clouds on Earth's climate, have been demonstrated on checkout flights aboard NASA's ER-2 aircraft.

  2. Jigsaw phase III: a miniaturized airborne 3-D imaging laser radar with photon-counting sensitivity for foliage penetration

    NASA Astrophysics Data System (ADS)

    Vaidyanathan, Mohan; Blask, Steven; Higgins, Thomas; Clifton, William; Davidsohn, Daniel; Carson, Ryan; Reynolds, Van; Pfannenstiel, Joanne; Cannata, Richard; Marino, Richard; Drover, John; Hatch, Robert; Schue, David; Freehart, Robert; Rowe, Greg; Mooney, James; Hart, Carl; Stanley, Byron; McLaughlin, Joseph; Lee, Eui-In; Berenholtz, Jack; Aull, Brian; Zayhowski, John; Vasile, Alex; Ramaswami, Prem; Ingersoll, Kevin; Amoruso, Thomas; Khan, Imran; Davis, William; Heinrichs, Richard

    2007-04-01

    Jigsaw three-dimensional (3D) imaging laser radar is a compact, light-weight system for imaging highly obscured targets through dense foliage semi-autonomously from an unmanned aircraft. The Jigsaw system uses a gimbaled sensor operating in a spot light mode to laser illuminate a cued target, and autonomously capture and produce the 3D image of hidden targets under trees at high 3D voxel resolution. With our MIT Lincoln Laboratory team members, the sensor system has been integrated into a geo-referenced 12-inch gimbal, and used in airborne data collections from a UH-1 manned helicopter, which served as a surrogate platform for the purpose of data collection and system validation. In this paper, we discuss the results from the ground integration and testing of the system, and the results from UH-1 flight data collections. We also discuss the performance results of the system obtained using ladar calibration targets.

  3. Airborne measurements of formaldehyde employing a high-performance tunable diode laser absorption system

    NASA Astrophysics Data System (ADS)

    Fried, Alan; Wert, Bryan P.; Walega, James G.; Richter, Dirk A.; Potter, William T.

    2002-09-01

    Formaldehyde (CH2O) is a ubiquitous component of both the remote atmosphere as well as the polluted urban atmosphere. This important gas-phase intermediate is a primary emission product from hydrocarbon combustion sources as well as from oxidation of natural hydrocarbons emitted by plants and trees. Through its subsequent decomposition, formaldehyde is a source of reactive hydrogen radicals, which control the oxidation capacity of the atmosphere. Because ambient CH2O concentrations attain levels as high as several tens of parts-per-billion (ppbv) in urban areas to levels as low as tens of parts-per-trillion (pptv) in the remote background atmosphere, ambient measurements become quite challenging, particularly on airborne platforms. The present paper discusses an airborne tunable diode laser absorption spectrometer, which has been developed and refined over the past 6 years, for such demanding measurements. The results from a recent study will be presented.

  4. Aerosol Profile Measurements from the NASA Langley Research Center Airborne High Spectral Resolution Lidar

    NASA Technical Reports Server (NTRS)

    Obland, Michael D.; Hostetler, Chris A.; Ferrare, Richard A.; Hair, John W.; Roers, Raymond R.; Burton, Sharon P.; Cook, Anthony L.; Harper, David B.

    2008-01-01

    Since achieving first light in December of 2005, the NASA Langley Research Center (LaRC) Airborne High Spectral Resolution Lidar (HSRL) has been involved in seven field campaigns, accumulating over 450 hours of science data across more than 120 flights. Data from the instrument have been used in a variety of studies including validation and comparison with the Cloud- Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite mission, aerosol property retrievals combining passive and active instrument measurements, aerosol type identification, aerosol-cloud interactions, and cloud top and planetary boundary layer (PBL) height determinations. Measurements and lessons learned from the HSRL are leading towards next-generation HSRL instrument designs that will enable even further studies of aerosol intensive and extensive parameters and the effects of aerosols on the climate system. This paper will highlight several of the areas in which the NASA Airborne HSRL is making contributions to climate science.

  5. Development of a high-altitude airborne dial system: The Lidar Atmospheric Sensing Experiment (LASE)

    NASA Technical Reports Server (NTRS)

    Browell, E. V.; Vaughan, W. R.; Hall, W. M.; Degnan, J. J.; Averill, R. D.; Wells, J. G.; Hinton, D. E.; Goad, J. H.

    1986-01-01

    The ability of a Differential Absorption Lidar (DIAL) system to measure vertical profiles of H2O in the lower atmosphere was demonstrated both in ground-based and airborne experiments. In these experiments, tunable lasers were used that required real-time experimenter control to locate and lock onto the atmospheric H2O absorption line for the DIAL measurements. The Lidar Atmospheric Sensing Experiment (LASE) is the first step in a long-range effort to develop and demonstrate an autonomous DIAL system for airborne and spaceborne flight experiments. The LASE instrument is being developed to measure H2O, aerosol, and cloud profiles from a high-altitude ER-2 (extended range U-2) aircraft. The science of the LASE program, the LASE system design, and the expected measurement capability of the system are discussed.

  6. A high-temperature heat sensitive element

    NASA Technical Reports Server (NTRS)

    Oguro, M.

    1986-01-01

    This invention concerns the high-temperature heat sensitive element which is stable at high temperatures. A solid solution of the main component MgO-Al2O3-Cr2O3-Fe2O3 which contains spinel crystal structure is mixed with the secondary component ZrO2 at the mol ratio of 100 : 0.1 to 5.0 and sintered to prepare a high-temperature heat sensitive element.

  7. Comparison of High and Low Density Airborne LIDAR Data for Forest Road Quality Assessment

    NASA Astrophysics Data System (ADS)

    Kiss, K.; Malinen, J.; Tokola, T.

    2016-06-01

    Good quality forest roads are important for forest management. Airborne laser scanning data can help create automatized road quality detection, thus avoiding field visits. Two different pulse density datasets have been used to assess road quality: high-density airborne laser scanning data from Kiihtelysvaara and low-density data from Tuusniemi, Finland. The field inventory mainly focused on the surface wear condition, structural condition, flatness, road side vegetation and drying of the road. Observations were divided into poor, satisfactory and good categories based on the current Finnish quality standards used for forest roads. Digital Elevation Models were derived from the laser point cloud, and indices were calculated to determine road quality. The calculated indices assessed the topographic differences on the road surface and road sides. The topographic position index works well in flat terrain only, while the standardized elevation index described the road surface better if the differences are bigger. Both indices require at least a 1 metre resolution. High-density data is necessary for analysis of the road surface, and the indices relate mostly to the surface wear and flatness. The classification was more precise (31-92%) than on low-density data (25-40%). However, ditch detection and classification can be carried out using the sparse dataset as well (with a success rate of 69%). The use of airborne laser scanning data can provide quality information on forest roads.

  8. A high gain antenna system for airborne satellite communication applications

    NASA Technical Reports Server (NTRS)

    Maritan, M.; Borgford, M.

    1990-01-01

    A high gain antenna for commercial aviation satellites communication is discussed. Electromagnetic and practical design considerations as well as candidate systems implementation are presented. An evaluation of these implementation schemes is given, resulting in the selection of a simple top mounted aerodynamic phased array antenna with a remotely located beam steering unit. This concept has been developed into a popular product known as the Canadian Marconi Company CMA-2100. A description of the technical details is followed by a summary of results from the first production antennas.

  9. Sensitization to Airborne Ascospores, Basidiospores, and Fungal Fragments in Allergic Rhinitis and Asthmatic Subjects in San Juan, Puerto Rico

    PubMed Central

    Rivera-Mariani, Félix E.; Nazario-Jiménez, Sylvette; López-Malpica, Fernando; Bolaños-Rosero, Benjamín

    2011-01-01

    Background Fungal spores are the predominant biological particulate in the atmosphere of Puerto Rico, yet their potential as allergens has not been studied in subjects with respiratory allergies. The purpose of this study was to determine the level of sensitization of subjects with respiratory allergies to these particles. Methods Serum samples were drawn from 33 subjects with asthma, allergic rhinitis, or nonallergic rhinitis and 2 controls with different skin prick test reactivity. An MK-3 sampler was used to collect air samples and the reactivity of the sera to fungal particles was detected with a halogen immunoassay. Results All subjects reacted to at least 1 fungal particle. Thirty-one subjects reacted to ascospores, 29 to basidiospores, 19 to hyphae/fungal fragments, and 12 to mitospores. The median percentage of haloes in allergic rhinitis subjects was 4.82% while asthma or nonallergic rhinitis subjects had values of 1.09 and 0.39%, respectively. Subjects with skin prick tests positive to 3, 2, 1, or no extract had 5.24, 1.09, 1.61, and, 0.57% of haloed particles, respectively. If skin prick tests were positive to basidiomycetes, pollen, animals, or deuteromycetes, the percentages of haloes were 4.72, 4.15, 3.63, and 3.31%, respectively. Of all haloed particles, 46% were unidentified, 25% ascospores, 20% basidiospores, 7% hyphae/fungal fragments, and 2% mitospores. IgE levels and the number of positive skin prick test extracts correlated with the percentage of haloes. Conclusion In tropical environments, sensitization to airborne basidiomycetes, ascomycetes, and fungal fragments seems to be more prevalent than sensitization to mitospores in subjects with active allergies, suggesting a possible role in exacerbations of respiratory allergies. PMID:21346362

  10. Laboratory evaluation of an airborne ozone instrument that compensates for altitude/sensitivity effects

    NASA Technical Reports Server (NTRS)

    Gregory, G. L.; Hudgins, C. H.; Edahl, R. A., Jr.

    1983-01-01

    One problem encountered in the use of air-quality instrumentation on aircraft is the variation of instrument sensitivity with pressure as the result of altitude changes of the aircraft. Many instruments experience sensitivity changes of as much as a factor of 2 at altitudes of 6 km. Discussed are recent modifications to a chemiluminescent (ethylene) ozone detector that allow the instrument to automatically compensate for pressure/sensitivity effects. The modification provides automated mass flow rate control for both the sample and ethylene gas flows. The flow control systems maintain flow rate to within 15 percent for a 100-torr instantaneous pressure change, and flow rates are returned to the desired set points within 10 s after the pressure change. During simulated altitude changes (300 m/min from mean sea level to 3-km altitude), flow rates were controlled to within 3 percent of the set point. Laboratory data are summarized verifying the operation of the instrument for a pressure range of 760 torr (sea level) to 350 torr (approximately 20,000 ft) and an ozone concentration range from 20 to approximately 700 ppb.

  11. Crop harvest in Central Europe causes episodes of high airborne Alternaria spore concentrations in Copenhagen

    NASA Astrophysics Data System (ADS)

    Skjøth, C. A.; Sommer, J.; Frederiksen, L.; Gosewinkel Karlson, U.

    2012-06-01

    This study tests the hypothesis that Danish agricultural areas are the main source to airborne Alternaria spores in Copenhagen, Denmark. We suggest that the source to the overall load is mainly local, but with intermittent Long Distance Transport (LDT) from more remote agricultural areas. This hypothesis is supported by investigating a 10 yr bi-hourly record of Alternaria spores in the air from Copenhagen. This record shows 232 clinically relevant episodes with a distinct daily profile. The data analysis also revealed potential LDT episodes almost every year. A source map and analysis of atmospheric transport suggest that LDT always originates from the main agricultural areas in Central Europe. A dedicated emission study in cereal crops under harvest during 2010 also supports our hypothesis. The emission study showed that although the fields had been treated against fungal infections, harvesting still produced large amounts of airborne fungal spores. It is likely that such harvesting periods can cause clinically relevant levels of fungal spores in the atmosphere. Our findings suggest that crop harvest in Central Europe causes episodes of high airborne Alternaria spore concentrations in Copenhagen as well as other urban areas in this region. It is likely that such episodes could be simulated using atmospheric transport models.

  12. High spatial resolution imaging of methane and other trace gases with the airborne Hyperspectral Thermal Emission Spectrometer (HyTES)

    NASA Astrophysics Data System (ADS)

    Hulley, Glynn C.; Duren, Riley M.; Hopkins, Francesca M.; Hook, Simon J.; Vance, Nick; Guillevic, Pierre; Johnson, William R.; Eng, Bjorn T.; Mihaly, Jonathan M.; Jovanovic, Veljko M.; Chazanoff, Seth L.; Staniszewski, Zak K.; Kuai, Le; Worden, John; Frankenberg, Christian; Rivera, Gerardo; Aubrey, Andrew D.; Miller, Charles E.; Malakar, Nabin K.; Sánchez Tomás, Juan M.; Holmes, Kendall T.

    2016-06-01

    Currently large uncertainties exist associated with the attribution and quantification of fugitive emissions of criteria pollutants and greenhouse gases such as methane across large regions and key economic sectors. In this study, data from the airborne Hyperspectral Thermal Emission Spectrometer (HyTES) have been used to develop robust and reliable techniques for the detection and wide-area mapping of emission plumes of methane and other atmospheric trace gas species over challenging and diverse environmental conditions with high spatial resolution that permits direct attribution to sources. HyTES is a pushbroom imaging spectrometer with high spectral resolution (256 bands from 7.5 to 12 µm), wide swath (1-2 km), and high spatial resolution (˜ 2 m at 1 km altitude) that incorporates new thermal infrared (TIR) remote sensing technologies. In this study we introduce a hybrid clutter matched filter (CMF) and plume dilation algorithm applied to HyTES observations to efficiently detect and characterize the spatial structures of individual plumes of CH4, H2S, NH3, NO2, and SO2 emitters. The sensitivity and field of regard of HyTES allows rapid and frequent airborne surveys of large areas including facilities not readily accessible from the surface. The HyTES CMF algorithm produces plume intensity images of methane and other gases from strong emission sources. The combination of high spatial resolution and multi-species imaging capability provides source attribution in complex environments. The CMF-based detection of strong emission sources over large areas is a fast and powerful tool needed to focus on more computationally intensive retrieval algorithms to quantify emissions with error estimates, and is useful for expediting mitigation efforts and addressing critical science questions.

  13. High sensitivity cymbal-based accelerometer

    SciTech Connect

    Sun Chengliang; Lam, K.H.; Choy, S.H.; Chan, H.L. W.; Zhao, X.-Z.; Choy, C.L.

    2006-03-15

    A high sensitivity piezoelectric accelerometer has been developed by replacing the conventional piezoelectric rings with a cymbal transducer. The sensitivity of the cymbal-based accelerometers containing cymbal transducers with different endcap thicknesses and different seismic masses has been measured as a function of driving frequency. Due to the high d{sub 33}{sup '} coefficient of the cymbal transducers, the cymbal-based accelerometers have a high sensitivity of {approx}97 pC/ms{sup -2} with the amplitude rise of 2.85% (<1 dB) at one-third of the mounted resonance frequency (3.38 kHz). The effect of the seismic mass, the resonance frequency, and d{sub 33}{sup '} coefficient of the cymbal transducers on the sensitivity and the frequency range of the cymbal-based accelerometers are reported.

  14. Airborne tunable diode laser sensor for high-precision concentration and flux measurements of carbon monoxide and methane

    NASA Technical Reports Server (NTRS)

    Sachse, G. W.; Collins, J. E., Jr.; Hill, G. F.; Wade, L. O.; Burney, L. G.; Ritter, J. A.

    1991-01-01

    An airborne tunable diode laser instrument is described that is capable of operating in two measurement modes. One mode provides high precision (0.1 percent CH4; 1 percent CO) measurements of CH4 and CO with a 5 second response time, and a second mode achieves the very fast response time that is necessary to make airborne eddy correlation flux measurements. Examples of data from atmospheric expeditions of the Global Tropospheric Experiment are presented.

  15. High Sensitivity deflection detection of nanowires

    SciTech Connect

    Sanii, Babak; Ashby, Paul

    2009-10-28

    A critical limitation of nanoelectromechanical systems (NEMS) is the lack of a high-sensitivity position detection mechanism. We introduce a noninterferometric optical approach to determine the position of nanowires with a high sensitivity and bandwidth. Its physical origins and limitations are determined by Mie scattering analysis. This enables a dramatic miniaturization of detectable cantilevers, with attendant reductions to the fundamental minimum force noise in highly damping environments. We measure the force noise of an 81{+-}9??nm radius Ag{sub 2}Ga nanowire cantilever in water at 6{+-}3??fN/{radical}Hz.

  16. High sensitivity deflection detection of nanowires.

    PubMed

    Sanii, Babak; Ashby, Paul D

    2010-04-01

    A critical limitation of nanoelectromechanical systems (NEMS) is the lack of a high-sensitivity position detection mechanism. We introduce a noninterferometric optical approach to determine the position of nanowires with a high sensitivity and bandwidth. Its physical origins and limitations are determined by Mie scattering analysis. This enables a dramatic miniaturization of detectable cantilevers, with attendant reductions to the fundamental minimum force noise in highly damping environments. We measure the force noise of an 81+/-9 nm radius Ag(2)Ga nanowire cantilever in water at 6+/-3 fN/square root(Hz). PMID:20481957

  17. Development and Utilization of High Precision Digital Elevation Data taken by Airborne Laser Scanner

    NASA Astrophysics Data System (ADS)

    Akutsu, Osamu; Ohta, Masataka; Isobe, Tamio; Ando, Hisamitsu, Noguchi, Takahiro; Shimizu, Masayuki

    2005-03-01

    Disasters caused by heavy rain in urban areas bring a damage such as chaos in the road and railway transport systems, power failure, breakdown of the telephone system and submersion of built up areas, subways and underground shopping arcades, etc. It is important to obtain high precision elevation data which shows the detailed landform because a slight height difference affects damages by flood very considerably. Therefore, The Geographical Survey Institute (GSI) is preparing 5m grid digital terrain model (DTM) based on precise ground elevation data taken by using airborne laser scanner. This paper describes the process and an example of the use of a 5m grid digital data set.

  18. APPLYING DATA ASSIMILATION AND ADJOINT SENSITIVITY TO EPIDEMIOLOGICAL AND POLICY STUDIES OF AIRBORNE PARTICULATE MATTER

    EPA Science Inventory

    Source-resolved fine particulate matter (PM) concentrations are needed at high spatial and temporal resolutions for epidemiological studies aimed at identifying more- and less-harmful types of PM. Building on recent advances in air quality modeling, data assimilation, and s...

  19. MODTRAN3: An update and recent validations against airborne high resolution interferometer measurements

    NASA Technical Reports Server (NTRS)

    Anderson, Gail P.; Wang, Jinxue; Chetwynd, James H.

    1995-01-01

    accuracy of the code is very important because any errors in the radiative transfer calculation will directly translate into errors in the derived surface reflectance. In this paper, the new solar irradiance calculated by Kurucz, which is adopted in MODTRAN3, will be presented. Recent validations of MODTRAN3 with airborne high resolution interferometer measurements over ocean will be discussed. Good agreeement between model calculations and measurements was achieved.

  20. Comparison of Aerosol Classification from Airborne High Spectral Resolution Lidar and the CALIPSO Vertical Feature Mask

    NASA Astrophysics Data System (ADS)

    Burton, S. P.; Ferrare, R. A.; Omar, A. H.; Hostetler, C. A.; Hair, J. W.; Rogers, R.; Obland, M. D.; Butler, C. F.; Cook, A. L.; Harper, D. B.

    2012-12-01

    The NASA Langley Research Center (LaRC) airborne High Spectral Resolution Lidar (HSRL-1) on the NASA B200 aircraft has acquired large datasets of aerosol extinction (532nm), backscatter (532 and 1064nm), and depolarization (532 and 1064nm) profiles during 349 science flights in 19 field missions across North America since 2006. The extinction-to-backscatter ratio ("lidar ratio"), aerosol depolarization ratios, and backscatter color ratio measurements from HSRL-1 are scale-invariant parameters that depend on aerosol type but not concentration. These four aerosol intensive parameters are combined to qualitatively classify HSRL aerosol measurements into eight separate composition types. The classification methodology uses models formed from "training cases" with known aerosol type. The remaining measurements are then compared with these models using the Mahalanobis distance. Aerosol products from the CALIPSO satellite include aerosol type information as well, which is used as input to the CALIPSO aerosol retrieval. CALIPSO aerosol types are inferred using a mix of aerosol loading-dependent parameters, estimated aerosol depolarization, and location, altitude, and surface type information. The HSRL instrument flies beneath the CALIPSO satellite orbit track, presenting the opportunity for comparisons between the HSRL aerosol typing and the CALIPSO Vertical Feature Mask Aerosol Subtype product, giving insight into the performance of the CALIPSO aerosol type algorithm. We find that the aerosol classification from the two instruments frequently agree for marine aerosols and pure dust, and somewhat less frequently for pollution and smoke. In addition, the comparison suggests that the CALIPSO polluted dust type is overly inclusive, encompassing cases of dust combined with marine aerosol as well as cases without much evidence of dust. Qualitative classification of aerosol type combined with quantitative profile measurements of aerosol backscatter and extinction has many useful

  1. Airborne measurements of Black Carbon using miniature high-performance Aethalometers during global circumnavigation campaign GLWF 2012

    NASA Astrophysics Data System (ADS)

    Močnik, Griša; Drinovec, Luka; Vidmar, Primož; Lenarčič, Matevž

    2013-04-01

    While ground-level measurements of atmospheric aerosols are routinely performed around the world, there exists very little data on their vertical and geographical distribution in the global atmosphere. This data is a crucial requirement for our understanding of the dispersion of pollutant species of anthropogenic origin, and their possible effects on radiative forcing, cloud condensation, and other phenomena which can contribute to adverse outcomes. Black Carbon (BC) is a unique tracer for combustion emissions, and can be detected rapidly and with great sensitivity by filter-based optical methods. It has no non-combustion sources and is not transformed by atmospheric processes. Its presence at altitude is unequivocal. Recent technical advances have led to the development of miniaturized instruments which can be operated on ultra-light aircraft, balloons or UAV's. From January to April 2012, a 'Pipistrel Virus' single-seat ultra-light aircraft flew around the world on a photographic and environmental-awareness mission. The flight track covered all seven continents; crossed all major oceans; and operated at altitudes around 3000 m ASL and up to 8900 m ASL. The aircraft carried a specially-developed high-sensitivity miniaturized dual-wavelength Aethalometer, which recorded BC concentrations with very high temporal resolution and sensitivity (see Reference below). We present examples of data from flight tracks over remote oceans, uninhabited land masses, and densely populated areas. Back-trajectories are used to show transport of polluted air masses. Measuring the dependence of the aerosol absorption on the wavelength, we show that aerosols produced during biomass combustion can be transported to high altitude in high concentrations. 1. __, Carbon Sampling Takes Flight, Science 2012, 335, 1286. 2. G. Močnik, L. Drinovec, M. Lenarčič, Airborne measurements of Black Carbon during the GLW Flight using miniature high-performance Aethalometers, accessed 8 January 2013

  2. High Sensitivity Optically Pumped Quantum Magnetometer

    PubMed Central

    Tiporlini, Valentina; Alameh, Kamal

    2013-01-01

    Quantum magnetometers based on optical pumping can achieve sensitivity as high as what SQUID-based devices can attain. In this paper, we discuss the principle of operation and the optimal design of an optically pumped quantum magnetometer. The ultimate intrinsic sensitivity is calculated showing that optimal performance of the magnetometer is attained with an optical pump power of 20 μW and an operation temperature of 48°C. Results show that the ultimate intrinsic sensitivity of the quantum magnetometer that can be achieved is 327 fT/Hz1/2 over a bandwidth of 26 Hz and that this sensitivity drops to 130 pT/Hz1/2 in the presence of environmental noise. The quantum magnetometer is shown to be capable of detecting a sinusoidal magnetic field of amplitude as low as 15 pT oscillating at 25 Hz. PMID:23766716

  3. Step-stare technique for airborne high-resolution infrared imaging

    NASA Astrophysics Data System (ADS)

    Lavigne, Valerie; Chevrette, Paul C.; Ricard, Benot; Zaccarin, Andre

    2004-08-01

    The Infrared Eye project was developed at DRDC Valcartier to improve the efficiency of airborne search and rescue operations. A high performance opto-mechanical pointing system was developed to allow fast positioning of a narrow field of view with high resolution, used for search and detection, over a wide field of view of lower resolution that optimizes area coverage. This system also enables the use of a step-stare technique, which rapidly builds a large area coverage image mosaic by step-staring a narrow field camera and properly tiling the resulting images. The resulting image mosaic covers the wide field of the current Infrared Eye, but with the high resolution of the narrow field. For the desired application, the camera will be fixed to an airborne platform using a stabilized mount and image positioning in the mosaic will be calculated using flight data provided by an altimeter, a GPS and an inertial unit. This paper presents a model of the complete system, a dynamic step-stare strategy that generates the image mosaic, a flight image taking simulator for strategy testing and some results obtained with this simulator.

  4. Accuracy assessment of airborne photogrammetrically derived high-resolution digital elevation models in a high mountain environment

    NASA Astrophysics Data System (ADS)

    Müller, Johann; Gärtner-Roer, Isabelle; Thee, Patrick; Ginzler, Christian

    2014-12-01

    High-resolution digital elevation models (DEMs) generated by airborne remote sensing are frequently used to analyze landform structures (monotemporal) and geomorphological processes (multitemporal) in remote areas or areas of extreme terrain. In order to assess and quantify such structures and processes it is necessary to know the absolute accuracy of the available DEMs. This study assesses the absolute vertical accuracy of DEMs generated by the High Resolution Stereo Camera-Airborne (HRSC-A), the Leica Airborne Digital Sensors 40/80 (ADS40 and ADS80) and the analogue camera system RC30. The study area is located in the Turtmann valley, Valais, Switzerland, a glacially and periglacially formed hanging valley stretching from 2400 m to 3300 m a.s.l. The photogrammetrically derived DEMs are evaluated against geodetic field measurements and an airborne laser scan (ALS). Traditional and robust global and local accuracy measurements are used to describe the vertical quality of the DEMs, which show a non Gaussian distribution of errors. The results show that all four sensor systems produce DEMs with similar accuracy despite their different setups and generations. The ADS40 and ADS80 (both with a ground sampling distance of 0.50 m) generate the most accurate DEMs in complex high mountain areas with a RMSE of 0.8 m and NMAD of 0.6 m They also show the highest accuracy relating to flying height (0.14‰). The pushbroom scanning system HRSC-A produces a RMSE of 1.03 m and a NMAD of 0.83 m (0.21‰ accuracy of the flying height and 10 times the ground sampling distance). The analogue camera system RC30 produces DEMs with a vertical accuracy of 1.30 m RMSE and 0.83 m NMAD (0.17‰ accuracy of the flying height and two times the ground sampling distance). It is also shown that the performance of the DEMs strongly depends on the inclination of the terrain. The RMSE of areas up to an inclination <40° is better than 1 m. In more inclined areas the error and outlier occurrence

  5. Recovery of Atmospheric Water Vapor Total Column Abundance from Imaging Spectrometer Data Around 940 nm - Sensitivity Analysis and Application to Airborne Visible/Infrared Imaging Spectrometer (AVIRI

    NASA Technical Reports Server (NTRS)

    Carrere, V.; Conel, J. E.

    1993-01-01

    Twosimple techniques to retrieve path precipitable water fromthe Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) high spectral resolution radiance data (Continuum Interpolated Band Ratio, CIBR, and Narrow/Wide Ratio, N/W), using the 940 nm water absorption band, are compared.

  6. Fiber specklegram sensors sensitivities at high temperatures

    NASA Astrophysics Data System (ADS)

    Rodriguez-Cobo, L.; Lomer, M.; Lopez-Higuera, J. M.

    2015-09-01

    In this work, the sensitivity of Fiber Specklegram Sensors to high temperatures (up to 800ºC) have been studied. Two multimode silica fibers have been introduced into a tubular furnace while a HeNe laser source was launched into a fiber edge, projecting speckle patterns to a commercial webcam. A computer generated different heating and cooling sweeps while the specklegram evolution was recorded. The achieved results exhibit a remarkably linearity in FSS's sensitivity for temperatures under 800ºC, following the thermal expansion of fused silica.

  7. Evaluation of eelgrass beds mapping using a high-resolution airborne multispectral scanner

    USGS Publications Warehouse

    Su, H.; Karna, D.; Fraim, E.; Fitzgerald, M.; Dominguez, R.; Myers, J.S.; Coffland, B.; Handley, L.R.; Mace, T.

    2006-01-01

    Eelgrass (Zostera marina) can provide vital ecological functions in stabilizing sediments, influencing current dynamics, and contributing significant amounts of biomass to numerous food webs in coastal ecosystems. Mapping eelgrass beds is important for coastal water and nearshore estuarine monitoring, management, and planning. This study demonstrated the possible use of high spatial (approximately 5 m) and temporal (maximum low tide) resolution airborne multispectral scanner on mapping eelgrass beds in Northern Puget Sound, Washington. A combination of supervised and unsupervised classification approaches were performed on the multispectral scanner imagery. A normalized difference vegetation index (NDVI) derived from the red and near-infrared bands and ancillary spatial information, were used to extract and mask eelgrass beds and other submerged aquatic vegetation (SAV) in the study area. We evaluated the resulting thematic map (geocoded, classified image) against a conventional aerial photograph interpretation using 260 point locations randomly stratified over five defined classes from the thematic map. We achieved an overall accuracy of 92 percent with 0.92 Kappa Coefficient in the study area. This study demonstrates that the airborne multispectral scanner can be useful for mapping eelgrass beds in a local or regional scale, especially in regions for which optical remote sensing from space is constrained by climatic and tidal conditions. ?? 2006 American Society for Photogrammetry and Remote Sensing.

  8. ATLAS: an airborne active linescan system for high-resolution topographic mapping

    NASA Astrophysics Data System (ADS)

    Willetts, David V.; Kightley, Peter J.; Mole, S. G.; Pearson, Guy N.; Pearson, P.; Coffey, Adrian S.; Stokes, Tim J.; Tapster, Paul R.; Westwood, M.

    2004-12-01

    High resolution ground mapping is of interest for survey and management of long linear features such as roads, railways and pipelines, and for georeferencing of areas such as flood plains for hydrological purposes. ATLAS (Airborne Topographic Laser System) is an active linescan system operating at the eyesafe wavelength of 1.5μm. Built for airborne survey, it is currently certified for use on a Twin Squirrel helicopter for operation from low levels to heights above 500 feet allowing commercial survey in built up areas. The system operates at a pulse repetition frequency of 56kHz with a line completed in 15ms, giving 36 points/m2 at the surface at the design flight speed. At each point the range to the ground is measured together with the scan angle of the system. This data is combined with a system attitude measurement from an integrated inertial navigation system and with system position derived from differential GPS data aboard the platform. A recording system captures the data with a synchronised time-stamp to enable post-processed reconstruction of a cloud of data points that will give a three-dimensional representation of the terrain, allowing the points to be located with respect to absolute Earth referenced coordinates to a precision of 5cm in three axes. This paper summarises the design, harmonisation, evaluation and performance of the system, and shows examples of survey data.

  9. Validation of CALIPSO Lidar Observations Using Data From the NASA Langley Airborne High Spectral Resolution Lidar

    NASA Technical Reports Server (NTRS)

    Hostetler, Chris; Hair, Johnathan; Liu, Zhaoyan; Ferrare, Rich; Harper, David; Cook, Anthony; Vaughan, Mark; Trepte, Chip; Winker, David

    2006-01-01

    This poster focuses on preliminary comparisons of data from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) spacecraft with data acquired by the NASA Langley Airborne High Spectral Resolution Lidar (HSRL). A series of 20 aircraft validation flights was conducted from 14 June through 27 September 2006, under both day and night lighting conditions and a variety of aerosol and cloud conditions. This poster presents comparisons of CALIOP measurements of attenuated backscatter at 532 and 1064 nm and depolarization at 532 nm with near coincident measurements from the Airborne HSRL as a preliminary assessment of CALIOP calibration accuracy. Note that the CALIOP data presented here are the pre-release version. These data have known artifacts in calibration which have been corrected in the December 8 CALIPSO data release which was not available at the time the comparisons were conducted for this poster. The HSRL data are also preliminary. No artifacts are known to exist; however, refinements in calibration and algorithms are likely to be implemented before validation comparisons are made final.

  10. Airborne High Spectral Resolution Lidar Aerosol Measurements during MILAGRO and TEXAQS/GOMACCS

    NASA Technical Reports Server (NTRS)

    Ferrare, Richard; Hostetler, Chris; Hair, John; Cook Anthony; Harper, David; Burton, Sharon; Clayton, Marian; Clarke, Antony; Russell, Phil; Redemann, Jens

    2007-01-01

    Two1 field experiments conducted during 2006 provided opportunities to investigate the variability of aerosol properties near cities and the impacts of these aerosols on air quality and radiative transfer. The Megacity Initiative: Local and Global Research Observations (MILAGRO) /Megacity Aerosol Experiment in Mexico City (MAX-MEX)/Intercontinental Chemical Transport Experiment-B (INTEX-B) joint experiment conducted during March 2006 investigated the evolution and transport of pollution from Mexico City. The Texas Air Quality Study (TEXAQS)/Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) (http://www.al.noaa.gov/2006/) conducted during August and September 2006 investigated climate and air quality in the Houston/Gulf of Mexico region. During both missions, the new NASA Langley airborne High Spectral Resolution Lidar (HSRL) was deployed on the NASA Langley B200 King Air aircraft and measured profiles of aerosol extinction, backscattering, and depolarization to: 1) characterize the spatial and vertical distributions of aerosols, 2) quantify aerosol extinction and optical thickness contributed by various aerosol types, 3) investigate aerosol variability near clouds, 4) evaluate model simulations of aerosol transport, and 5) assess aerosol optical properties derived from a combination of surface, airborne, and satellite measurements.

  11. Urban Building Collapse Detection Using Very High Resolution Imagery and Airborne LIDAR Data

    NASA Astrophysics Data System (ADS)

    Wang, X.; Li, P.

    2013-07-01

    The increasing availability of very high resolution (VHR) remotely sensed images makes it possible to detect and assess urban building damages in the aftermath of earthquake disasters by using these data. However, the accuracy obtained using spectral features from VHR data alone is comparatively low, since both undamaged and collapsed buildings are spectrally similar. The height information provided by airborne LiDAR (Light Detection And Ranging) data is complementary to VHR imagery. Thus, combination of these two datasets will be beneficial to the automatic and accurate extraction of building collapse. In this study, a hierarchical multi-level method of building collapse detection using bi-temporal (pre- and post-earthquake) VHR images and postevent airborne LiDAR data was proposed. First, buildings, bare ground, vegetation and shadows were extracted using post-event image and LiDAR data and masked out. Then building collapse was extracted using the bi-temporal VHR images of the remaining area with a one-class classifier. The proposed method was evaluated using bi-temporal VHR images and LiDAR data of Port au Prince, Haiti, which was heavily hit by an earthquake in January 2010. The method was also compared with some existing methods. The results showed that the method proposed in this study significantly outperformed the existing methods, with improvement range of 47.6% in kappa coefficient. The proposed method provided a fast and reliable way of detecting urban building collapse, which can also be applied to relevant applications.

  12. Diaphragm based high sensitive FBG pressure sensor

    NASA Astrophysics Data System (ADS)

    Vengal Rao, P.; Srimannarayana, K.; Sai Shankar, M.; Kishore, P.

    2013-06-01

    A high sensitive pressure sensor based on Fiber Bragg grating (FBG) integrated with a thin metal diaphragm was designed and demonstrated. To enhance the pressure sensitivity FBG is firmly glued across the diameter of the diaphragm. Under pressure, the diaphragm deforms and produces an induced strain along the length of the fiber causes shift in Bragg wavelength of the FBG. Pressure measurement is made by measuring the Bragg wavelength shift against change in pressure. The sensor was tested up to the maximum pressure of 140 psi and the corresponding pressure sensitivity was found to be 0.0204 nm/psi, which is approximately 970 times higher than that can be achieved with a bare FBG. The experimental results show good agreement with the theoretical results and possess good linearity and repeatability. This sensor can be used for the measurement of medium pressure, liquid level and depth of underwater.

  13. High blood pressure and visual sensitivity

    NASA Astrophysics Data System (ADS)

    Eisner, Alvin; Samples, John R.

    2003-09-01

    The study had two main purposes: (1) to determine whether the foveal visual sensitivities of people treated for high blood pressure (vascular hypertension) differ from the sensitivities of people who have not been diagnosed with high blood pressure and (2) to understand how visual adaptation is related to standard measures of systemic cardiovascular function. Two groups of middle-aged subjects-hypertensive and normotensive-were examined with a series of test/background stimulus combinations. All subjects met rigorous inclusion criteria for excellent ocular health. Although the visual sensitivities of the two subject groups overlapped extensively, the age-related rate of sensitivity loss was, for some measures, greater for the hypertensive subjects, possibly because of adaptation differences between the two groups. Overall, the degree of steady-state sensitivity loss resulting from an increase of background illuminance (for 580-nm backgrounds) was slightly less for the hypertensive subjects. Among normotensive subjects, the ability of a bright (3.8-log-td), long-wavelength (640-nm) adapting background to selectively suppress the flicker response of long-wavelength-sensitive (LWS) cones was related inversely to the ratio of mean arterial blood pressure to heart rate. The degree of selective suppression was also related to heart rate alone, and there was evidence that short-term changes of cardiovascular response were important. The results suggest that (1) vascular hypertension, or possibly its treatment, subtly affects visual function even in the absence of eye disease and (2) changes in blood flow affect retinal light-adaptation processes involved in the selective suppression of the flicker response from LWS cones caused by bright, long-wavelength backgrounds.

  14. Highly Energetic, Low Sensitivity Aromatic Peroxy Acids.

    PubMed

    Gamage, Nipuni-Dhanesha H; Stiasny, Benedikt; Stierstorfer, Jörg; Martin, Philip D; Klapötke, Thomas M; Winter, Charles H

    2016-02-18

    The synthesis, structure, and energetic materials properties of a series of aromatic peroxy acid compounds are described. Benzene-1,3,5-tris(carboperoxoic) acid is a highly sensitive primary energetic material, with impact and friction sensitivities similar to those of triacetone triperoxide. By contrast, benzene-1,4-bis(carboperoxoic) acid, 4-nitrobenzoperoxoic acid, and 3,5-dinitrobenzoperoxoic acid are much less sensitive, with impact and friction sensitivities close to those of the secondary energetic material 2,4,6-trinitrotoluene. Additionally, the calculated detonation velocities of 3,5-dinitrobenzoperoxoic acid and 2,4,6-trinitrobenzoperoxoic acid exceed that of 2,4,6-trinitrotoluene. The solid-state structure of 3,5-dinitrobenzoperoxoic acid contains intermolecular O-H⋅⋅⋅O hydrogen bonds and numerous N⋅⋅⋅O, C⋅⋅⋅O, and O⋅⋅⋅O close contacts. These attractive lattice interactions may account for the less sensitive nature of 3,5-dinitrobenzoperoxoic acid. PMID:26743434

  15. High repetition rate frequency-doubled Nd:YAG laser for airborne bathymetry

    NASA Astrophysics Data System (ADS)

    Northam, D. B.; Guerra, M. A.; Mack, M. E.; Itzkan, I.; Deradourian, C.

    1981-03-01

    A flashlamp pumped frequency-doubled Nd:YAG laser producing 7-nsec 2.8-mJ pulses at 530 nm and 400 pps has been developed for use in airborne bathymetry. A flashlamp gas mixture of krypton and xenon provides efficient laser operation and rapid lamp recovery. Pulse transmission mode operation is used to achieve a narrow pulse width. Thermally induced lensing and birefringence in the rod are compensated for in the optical resonator. Rapid, high repetition rate Pockels cell switching is accomplished with a thyratron driver. A CD(asterisk)A crystal cut for 85 deg phase matching at 55 C is used to provide high conversion efficiency second harmonic generation.

  16. Highly sensitive catalytic spectrophotometric determination of ruthenium

    NASA Astrophysics Data System (ADS)

    Naik, Radhey M.; Srivastava, Abhishek; Prasad, Surendra

    2008-01-01

    A new and highly sensitive catalytic kinetic method (CKM) for the determination of ruthenium(III) has been established based on its catalytic effect on the oxidation of L-phenylalanine ( L-Pheala) by KMnO 4 in highly alkaline medium. The reaction has been followed spectrophotometrically by measuring the decrease in the absorbance at 526 nm. The proposed CKM is based on the fixed time procedure under optimum reaction conditions. It relies on the linear relationship where the change in the absorbance (Δ At) versus added Ru(III) amounts in the range of 0.101-2.526 ng ml -1 is plotted. Under the optimum conditions, the sensitivity of the proposed method, i.e. the limit of detection corresponding to 5 min is 0.08 ng ml -1, and decreases with increased time of analysis. The method is featured with good accuracy and reproducibility for ruthenium(III) determination. The ruthenium(III) has also been determined in presence of several interfering and non-interfering cations, anions and polyaminocarboxylates. No foreign ions interfered in the determination ruthenium(III) up to 20-fold higher concentration of foreign ions. In addition to standard solutions analysis, this method was successfully applied for the quantitative determination of ruthenium(III) in drinking water samples. The method is highly sensitive, selective and very stable. A review of recently published catalytic spectrophotometric methods for the determination of ruthenium(III) has also been presented for comparison.

  17. Demonstration of high-rate laser communications from fast airborne platform: flight campaign and results

    NASA Astrophysics Data System (ADS)

    Moll, Florian; Mitzkus, Wolfgang; Horwath, Joachim; Shrestha, Amita; Brechtelsbauer, Martin; Martin, Luis; Lozano, Alberto; Diaz Gonzalez, Dionisio

    2014-10-01

    Some current and future airborne payloads like high resolution cameras and radar systems need high channel capacity to transmit their data from air to ground in near real-time. Especially in reconnaissance and surveillance missions, it is important to downlink huge amount of data in very short contact times to a ground station during a flyby. Aeronautical laser communications can supply the necessary high data-rates for this purpose. Within the project DODfast (Demonstration of Optical Data link fast) a laser link from a fast flying platform was demonstrated. The flight platform was a Panavia Tornado with the laser communication terminal installed in an attached avionic demonstrator pod. The air interface was a small glass dome protecting the beam steering assembly. All other elements were integrated in a small box inside the Pod's fuselage. The receiver station was DLR's Transportable Optical Ground Station equipped with a free-space receiver front-end. Downlink wavelength for communication and uplink wavelength for beacon laser were chosen from the optical C-band DWDM grid. The test flights were carried out at the end of November 2013 near the Airbus Defence and Space location in Manching, Germany. The campaign successfully demonstrated the maturity and readiness of laser communication with a data-rate of 1.25 Gbit/s for aircraft downlinks. Pointing, acquisition and tracking performance of the airborne terminal and the ground station could be measured at aircraft speed up to 0.7 Mach and video data from an onboard camera has been transmitted. Link distances with stable tracking were up to 79 km and distance with data transmission over 50 km. In this paper, we describe the system architecture, the flight campaign and the results.

  18. Geodetic Imaging Lidar: Applications for high-accuracy, large area mapping with NASA's upcoming high-altitude waveform-based airborne laser altimetry Facility

    NASA Astrophysics Data System (ADS)

    Blair, J. B.; Rabine, D.; Hofton, M. A.; Citrin, E.; Luthcke, S. B.; Misakonis, A.; Wake, S.

    2015-12-01

    Full waveform laser altimetry has demonstrated its ability to capture highly-accurate surface topography and vertical structure (e.g. vegetation height and structure) even in the most challenging conditions. NASA's high-altitude airborne laser altimeter, LVIS (the Land Vegetation, and Ice Sensor) has produced high-accuracy surface maps over a wide variety of science targets for the last 2 decades. Recently NASA has funded the transition of LVIS into a full-time NASA airborne Facility instrument to increase the amount and quality of the data and to decrease the end-user costs, to expand the utilization and application of this unique sensor capability. Based heavily on the existing LVIS sensor design, the Facility LVIS instrument includes numerous improvements for reliability, resolution, real-time performance monitoring and science products, decreased operational costs, and improved data turnaround time and consistency. The development of this Facility instrument is proceeding well and it is scheduled to begin operations testing in mid-2016. A comprehensive description of the LVIS Facility capability will be presented along with several mission scenarios and science applications examples. The sensor improvements included increased spatial resolution (footprints as small as 5 m), increased range precision (sub-cm single shot range precision), expanded dynamic range, improved detector sensitivity, operational autonomy, real-time flight line tracking, and overall increased reliability and sensor calibration stability. The science customer mission planning and data product interface will be discussed. Science applications of the LVIS Facility include: cryosphere, territorial ecology carbon cycle, hydrology, solid earth and natural hazards, and biodiversity.

  19. Laser measurement of extinction coefficients of highly absorbing liquids. [airborne oil spill monitoring application

    NASA Technical Reports Server (NTRS)

    Hoge, F. E.; Kincaid, J. S.

    1980-01-01

    A coaxial dual-channel laser system has been developed for the measurement of extinction coefficients of highly absorbing liquids. An empty wedge-shaped sample cell is first translated laterally through a He-Ne laser beam to measure the differential thickness using interference fringes in reflection. The wedge cell is carefully filled with the oil sample and translated through the coaxially positioned dye laser beam for the differential attenuation or extinction measurement. Optional use of the instrumentation as a single-channel extinction measurement system and also as a refractometer is detailed. The system and calibration techniques were applied to the measurement of two crude oils whose extinction values were required to complete the analysis of airborne laser data gathered over four controlled spills.

  20. High-resolution airborne gravity imaging over James Ross Island (West Antarctica)

    USGS Publications Warehouse

    Jordan, T.A.; Ferraccioli, F.; Jones, P.C.; Smellie, J.L.; Ghidella, M.; Corr, H. F. J.; Zakrajsek, A.F.

    2007-01-01

    James Ross Island (JRI) exposes a Miocene-Recent alkaline basaltic volcanic complex that developed in a back-arc, east of the northern Antarctic Peninsula. JRI has been the focus of several geological studies because it provides a window on Neogene magmatic processes and paleoenvironments. However, little is known about its internal structure. New airborne gravity data were collected as part of the first high-resolution aerogeophysical survey flown over the island and reveal a prominent negative Bouguer gravity anomaly over Mt Haddington. This is intriguing as basaltic volcanoes are typically associated with positive Bouguer anomalies, linked to underlying mafic intrusions. The negative Bouguer anomaly may be associated with a hitherto unrecognised low-density sub-surface body, such as a breccia-filled caldera, or a partially molten magma chamber.

  1. Airborne ROWS data report for the high resolution experiment, June 1993

    NASA Technical Reports Server (NTRS)

    Vandemark, D.; Hines, D.; Bailey, S.; Stewart, K.

    1994-01-01

    Airborne radar ocean wave spectrometer (ROWS) data collected during the Office of Naval Research's High Resolution Remote Sensing Experiment of June 1993 are presented. This data summary covers six flights made using NASA's T-39 aircraft over a region of the North Atlantic off the coast of North Carolina and includes multiple crossings of the gulf stream. The Ku-band ROWS was operated in a configuration which continuously switched between an altimeter and a spectrometer channel. Data derived from the two channels include altimeter radar cross section, altimeter-derived sea surface mean square slope and wind speed, and directional and nondirectional longwave spectra. Discussion is provided for several events of particular interest.

  2. High-energy, efficient, 30-Hz ultraviolet laser sources for airborne ozone-lidar systems.

    PubMed

    Elsayed, Khaled A; Chen, Songsheng; Petway, Larry B; Meadows, Byron L; Marsh, Waverly D; Edwards, William C; Barnes, James C; DeYoung, Russell J

    2002-05-20

    Two compact, high-pulse-energy, injection-seeded, 30-Hz frequency-doubled Nd:YAG-laser-pumped Ti: sapphire lasers were developed and operated at infrared wavelengths of 867 and 900 nm. Beams with laser pulse energy >30 mJ at ultraviolet wavelengths of 289 and 300 nm were generated through a tripling of the frequencies of these Ti:sapphire lasers. This work is directed at the replacement of dye lasers for use in an airborne ozone differential absorption lidar system. The ultraviolet pulse energy at 289 and 300 nm had 27% and 31% absolute optical energy conversion efficiencies from input pulse energies at 867 and 900 nm, respectively. PMID:12027160

  3. Characterization of Cirrus Cloud Properties by Airborne Differential Absorption and High Spectral Resolution Lidar Measurements

    NASA Astrophysics Data System (ADS)

    Ehret, G.; Gross, S.; Schäfler, A.; Wirth, M.; Fix, A.; Kiemle, C.

    2014-12-01

    Despite the large impact of cirrus clouds on the Earth's climate system, their effects are still only poorly understood. Our knowledge of the climate effect of cirrus clouds is mainly based on theoretical simulations using idealized cloud structure and microphysics, as well as radiative transfer approximations. To improve the representation of cirrus clouds in idealized simulations and circulation models, we need a better understanding of the micro- and macrophysical properties of cirrus clouds. Airborne lidar measurements provide two-dimensional information of the atmospheric structure, and are thus a suitable tool to study the fine-structure of cirrus clouds, as well as their macrophysical properties. Aerosol and water vapor was measured with the airborne high spectral resolution lidar (HSRL) and differential absorption lidar (DIAL) system WALES of the German Aerospace Center (DLR), Oberpfaffenhofen. The system was operated onboard the German high altitude and long range research aircraft HALO during the Next-generation remote sensing for validation studies campaign (NARVAL) in December 2013 over the tropical North-Atlantic and in January 2014 out of Iceland, and during the ML-Cirrus campaign in March/April 2014 over Central and Southern Europe. During NARVAL 18 flights with more than 110 flight hours were performed providing a large number of cirrus cloud overpasses with combined lidar and radar instrumentation. In the framework of the ML-Cirrus campaign 17 flights with more than 80 flight hours were performed to characterize cirrus cloud properties in different environmental conditions using a combination of remote sensing (e.g. lidar) and in-situ observations. In our presentation we will give a general overview of the campaigns and of the WALES measurements. We will show first results from the aerosol and water vapor lidar measurements with focus on the structure of cirrus clouds, the humidity distribution within and outside the cloud and on the impact of the

  4. Highly sensitive beam steering with plasmonic antenna

    PubMed Central

    Rui, Guanghao; Zhan, Qiwen

    2014-01-01

    In this work, we design and study a highly sensitive beam steering device that integrates a spiral plasmonic antenna with a subwavelength metallic waveguide. The short effective wavelength of the surface plasmon polaritons (SPPs) mode supported by the metallic waveguide is exploited to dramatically miniaturize the device and improve the sensitivity of the beam steering. Through introducing a tiny displacement of feed point with respect to the geometrical center of the spiral plasmonic antenna, the direction of the radiation can be steered at considerably high angles. Simulation results show that steering angles of 8°, 17° and 34° are obtainable for a displacement of 50 nm, 100 nm and 200 nm, respectively. Benefiting from the reduced device size and the shorter SPP wavelength, the beam steering sensitivity of the beam steering is improved by 10-fold compared with the case reported previously. This miniature plasmonic beam steering device may find many potential applications in quantum optical information processing and integrated photonic circuits. PMID:25091405

  5. Highly sensitive nanoscale spin-torque diode

    NASA Astrophysics Data System (ADS)

    Miwa, S.; Ishibashi, S.; Tomita, H.; Nozaki, T.; Tamura, E.; Ando, K.; Mizuochi, N.; Saruya, T.; Kubota, H.; Yakushiji, K.; Taniguchi, T.; Imamura, H.; Fukushima, A.; Yuasa, S.; Suzuki, Y.

    2014-01-01

    Highly sensitive microwave devices that are operational at room temperature are important for high-speed multiplex telecommunications. Quantum devices such as superconducting bolometers possess high performance but work only at low temperature. On the other hand, semiconductor devices, although enabling high-speed operation at room temperature, have poor signal-to-noise ratios. In this regard, the demonstration of a diode based on spin-torque-induced ferromagnetic resonance between nanomagnets represented a promising development, even though the rectification output was too small for applications (1.4 mV mW-1). Here we show that by applying d.c. bias currents to nanomagnets while precisely controlling their magnetization-potential profiles, a much greater radiofrequency detection sensitivity of 12,000 mV mW-1 is achievable at room temperature, exceeding that of semiconductor diode detectors (3,800 mV mW-1). Theoretical analysis reveals essential roles for nonlinear ferromagnetic resonance, which enhances the signal-to-noise ratio even at room temperature as the size of the magnets decreases.

  6. Spectra-view: A high performance, low-cost multispectral airborne imaging system

    SciTech Connect

    Helder, D.

    1996-11-01

    Although a variety of airborne platforms are available for collecting remote sensing data, a niche exists for a low cost, compact systemd capable of collecting accurate visible and infrared multispectral data in a digital format. To fill this void, an instrument known as Spectra-View was developed by Airborne Data Systems. Multispectral data is collected in the visible and near-infrared using an array of CCD cameras with appropriate spectral filtering. Infrared imaging is accomplished using commercially available cameras. Although the current system images in five spectral bands, a modular design approach allows various configurations for imaging in the visible and infrared regions with up to 10 or more channels. It was built entirely through integration of readily available commercial components, is compact enough to fly in an aircraft as small as a Cessna 172, and can record imagery at airspeeds in excess of 150 knots. A GPS-based navigation system provides a course deviation indicator for the pilot to follow and allows for georeferencing of the data. To maintain precise pointing knowledge, and at the same time keep system cost low, attitude sensors are mounted directly with the cameras rather than using a stabilized mounting system. Information is collect during camera firing of aircraft/camera attitude along the yaw, pitch, and roll axes. All data is collected in a digital format on a hard disk that is removable during flight so that virtually unlimited amounts of data may be recorded. Following collection, imagery is readily available for viewing and incorporation into computer-based systems for analysis and reduction. Ground processing software has been developed to perform radiometric calibration and georeference the imagery. Since June, 1995, the system has been collecting high-quality data in a variety of applications for numerous customers including applications in agriculture, forestry, and global change research. Several examples will be presented.

  7. High sensitive materials in medical holographic microscopy

    NASA Astrophysics Data System (ADS)

    Osanlou, A.; Snashall, E.; Osanlou, O.; Osanlou, R.; Mirlis, E.; Shi, Lishen; Bjelkhagen, H.

    2015-02-01

    High sensitivity is defined in relation to the energy required to perform holographic recording. High sensitivity in silver halide materials is their main advantage over other similarly high resolving power holographic recording materials. This work reports progress on the development of silver halide based 'true colour holographic imaging', under a microscope. A thin layer of ultrafine grains of silver halide crystals of around 10 nm average diameter, dispersed in a colloid and coated on a substrate is used as the recording media. The significance of this method so far, is in its ability to produce 'true colour' three-dimensional images of specimen. The recordings have an appreciable depth, permitting the observer to scan through the image under a microscope, as one might with a real specimen sample. Current methods could perform ' True colour holographic imaging' directly under a microscope. The recording methodology has the potential for deeper complex and scattering media imaging, using very small pulses of appropriate laser wavelengths. The methodology, using novel nanosize panchromatic recording media consisting of dispersed fine nano grain crystals, could potentially revolutionise related medical imaging techniques. Future development of digital media will allow it to be utilized in this manner.

  8. The high sensitivity double beta spectrometer TGV

    NASA Astrophysics Data System (ADS)

    Briancon, Ch.; Brudanin, V. B.; Egorov, V. G.; Janout, Z.; Koníček, J.; Kovalík, A.; Kovalenko, V. E.; Kubašta, J.; Pospíšil, S.; Revenko, A. V.; Rukhadze, N. I.; Salamatin, A. V.; Sandukovsky, V. G.; Štekl, I.; Timkin, V. V.; Tsupko-Sitnikov, V. V.; Vorobel, V.; Vylov, Ts.

    1996-02-01

    A high sensitivity double beta spectrometer TGV (Telescope Germanium Vertical) has been developed. It is based on 16 HPGe detectors of volume 1200 × 6 mm 3 each in the same cryostat. The TGV spectrometer was proposed for the study of ultrarare nuclear processes (e.g. 2νββ, 0νββ, 2νEC/EC). Details of the TGV spectrometer construction are described, the principles of background suppression, the results of Monte Carlo simulations and the results of test background measurements (in Dubna and Modane underground laboratory) are provided.

  9. [Clinical interpretation of high sensitivity troponin T].

    PubMed

    Alquézar Arbé, Aitor; Santaló Bel, Miguel; Sionis, Alessandro

    2015-09-21

    Determination of cardiac troponin (cTn) is necessary for the diagnosis of acute myocardial infarction without ST segment elevation. However Tnc can be released in other clinical situations. The development of high-sensitive cTn T assays (hs-cTnT) improves the management of patients with suspected acute coronary syndrome. Here, we provide an overview of the diverse causes of hs-cTnT elevation and recommend strategies for the clinical interpretation of the test result. PMID:25620025

  10. Photodetector having high speed and sensitivity

    DOEpatents

    Morse, Jeffrey D.; Mariella, Jr., Raymond P.

    1991-01-01

    The present invention provides a photodetector having an advantageous combination of sensitivity and speed; it has a high sensitivity while retaining high speed. In a preferred embodiment, visible light is detected, but in some embodiments, x-rays can be detected, and in other embodiments infrared can be detected. The present invention comprises a photodetector having an active layer, and a recombination layer. The active layer has a surface exposed to light to be detected, and comprises a semiconductor, having a bandgap graded so that carriers formed due to interaction of the active layer with the incident radiation tend to be swept away from the exposed surface. The graded semiconductor material in the active layer preferably comprises Al.sub.1-x Ga.sub.x As. An additional sub-layer of graded In.sub.1-y Ga.sub.y As may be included between the Al.sub.1-x Ga.sub.x As layer and the recombination layer. The recombination layer comprises a semiconductor material having a short recombination time such as a defective GaAs layer grown in a low temperature process. The recombination layer is positioned adjacent to the active layer so that carriers from the active layer tend to be swept into the recombination layer. In an embodiment, the photodetector may comprise one or more additional layers stacked below the active and recombination layers. These additional layers may include another active layer and another recombination layer to absorb radiation not absorbed while passing through the first layers. A photodetector having a stacked configuration may have enhanced sensitivity and responsiveness at selected wavelengths such as infrared.

  11. High Sensitivity Imprint Measurements on Nike Laser

    NASA Astrophysics Data System (ADS)

    Karasik, Max

    2005-10-01

    Hydrodynamic instability seeded by laser non-uniformity (laser imprint) is an important factor in performance of direct-drive ICF targets. Most of the imprint occurs during the initial low-intensity (``foot'') part of the pulse, necessary to compress the target to achieve high gain. Experiments are carried out on Nike KrF laser with induced spatial incoherence (ISI) smoothing. The amount of imprint is varied by changing the uniformity the foot of the pulse. The resulting Raleigh-Taylor (RT) amplified areal mass non-uniformity is measured by face-on x-ray radiography using Bragg reflection from a curved crystal coupled to an x-ray streak camera. The streak camera was recently retrofitted with a new high sensitivity CCD camera. The sensitivity of the CCD has enabled it to be fiberoptically coupled directly to the streak camera output, without an image intensifier and lens coupling. This gave an increased overall spatial resolution as well as lower noise. Because of the strong short wavelength component of RT amplified imprint, the increased resolution and lower noise resulted in much lower noise floor in the measurement. Experimental results are compared with 2D simulations using FAST hydrocode for a range of foot uniformities and intensities. Work supported by the U. S. DOE/NNSA.

  12. High-sensitivity detection of TNT

    PubMed Central

    Pushkarsky, Michael B.; Dunayevskiy, Ilya G.; Prasanna, Manu; Tsekoun, Alexei G.; Go, Rowel; Patel, C. Kumar N.

    2006-01-01

    We report high-sensitivity detection of 2,4,6-trinitrotoluene (TNT) by using laser photoacoustic spectroscopy where the laser radiation is obtained from a continuous-wave room temperature high-power quantum cascade laser in an external grating cavity geometry. The external grating cavity quantum cascade laser is continuously tunable over ≈400 nm around 7.3 μm and produces a maximum continuous-wave power of ≈200 mW. The IR spectroscopic signature of TNT is sufficiently different from that of nitroglycerine so that unambiguous detection of TNT without false positives from traces of nitroglycerine is possible. We also report the results of spectroscopy of acetylene in the 7.3-μm region to demonstrate continuous tunability of the IR source. PMID:17164325

  13. High Resolution Airborne Laser Scanning and Hyperspectral Imaging with a Small Uav Platform

    NASA Astrophysics Data System (ADS)

    Gallay, Michal; Eck, Christoph; Zgraggen, Carlo; Kaňuk, Ján; Dvorný, Eduard

    2016-06-01

    The capabilities of unmanned airborne systems (UAS) have become diverse with the recent development of lightweight remote sensing instruments. In this paper, we demonstrate our custom integration of the state-of-the-art technologies within an unmanned aerial platform capable of high-resolution and high-accuracy laser scanning, hyperspectral imaging, and photographic imaging. The technological solution comprises the latest development of a completely autonomous, unmanned helicopter by Aeroscout, the Scout B1-100 UAV helicopter. The helicopter is powered by a gasoline two-stroke engine and it allows for integrating 18 kg of a customized payload unit. The whole system is modular providing flexibility of payload options, which comprises the main advantage of the UAS. The UAS integrates two kinds of payloads which can be altered. Both payloads integrate a GPS/IMU with a dual GPS antenna configuration provided by OXTS for accurate navigation and position measurements during the data acquisition. The first payload comprises a VUX-1 laser scanner by RIEGL and a Sony A6000 E-Mount photo camera. The second payload for hyperspectral scanning integrates a push-broom imager AISA KESTREL 10 by SPECIM. The UAS was designed for research of various aspects of landscape dynamics (landslides, erosion, flooding, or phenology) in high spectral and spatial resolution.

  14. High-resolution measurements of surface topography with airborne laser altimetry and the global positioning system

    NASA Technical Reports Server (NTRS)

    Garvin, James B.; Bufton, Jack L.; Cavanaugh, John F.; Krabill, William B.; Clem, Thomas D.; Frederick, Earl B.; Ward, John L.

    1991-01-01

    Recently, an airborne lidar system that measures laser pulse time-of-flight and the distortion of the pulse waveform upon reflection from earth surface terrain features was developed and is now operational. This instrument is combined with Global Positioning System (GPS) receivers and a two-axis gyroscope for accurate recovery of aircraft position and pointing attitude. The laser altimeter system is mounted on a high-altitude aircraft platform and operated in a repetitively-pulsed mode for measurements of surface elevation profiles at nadir. The laser transmitter makes use of recently developed short-pulse diode-pumped solid-state laser technology in Q-switched Nd:YAG operating at its fundamental wavelength of 1064 nm. A reflector telescope and silicon avalanche photodiode are the basis of the optical receiver. A high-speed time-interval unit and a separate high-bandwidth waveform digitizer under microcomputer control are used to process the backscattered pulses for measurements of terrain. Other aspects of the lidar system are briefly discussed.

  15. COLLECTION OF AIRBORNE PARTICLES BY A HIGH-GRADIENT PERMANENT MAGNETIC METHOD

    SciTech Connect

    Cheng, Mengdawn; Allman, Steve L; Ludtka, Gerard Michael; Avens, Larry R

    2014-01-01

    We report on the use of magnetic force in collection of airborne particles by a high- gradient permanent magnetic separation (HGPMS) device. Three aerosol particles of different magnetic susceptibility (NaCl, CuO, and Fe2O3) were generated in the electrical mobility size range of 10 to 200 nm and were used to study HGPMS collection. One HGPMS matrix element, made of stainless steel wool, was used in the device configuration. Three flow rates were selected to simulate the environmental wind speeds of interest to the study. Magnetic force was found to exhibit an insignificant effect on the separation of NaCl particles, even in the HGPMS configuration. Diffusion was a major mechanism in the removal of the diamagnetic particles; however, diffusion is insignificant under the influence of a high-gradient magnetic field for paramagnetic or ferromagnetic particles. The HGPMS showed high-performance collection (> 99%) of paramagnetic CuO and ferromagnetic Fe2O3 particles for particle sizes greater than or equal to 60 nm. As the wind speed increases, the influence of the magnetic force weakens, and the capability to remove particles from the gas stream diminishes. The results suggest that the HGPMS principle could be explored for development of an advanced miniaturized passive aerosol collector.

  16. High speed curved position sensitive detector

    DOEpatents

    Hendricks, Robert W.; Wilson, Jack W.

    1989-01-01

    A high speed curved position sensitive porportional counter detector for use in x-ray diffraction, the detection of 5-20 keV photons and the like. The detector employs a planar anode assembly of a plurality of parallel metallic wires. This anode assembly is supported between two cathode planes, with at least one of these cathode planes having a serpentine resistive path in the form of a meander having legs generally perpendicular to the anode wires. This meander is produced by special microelectronic fabrication techniques whereby the meander "wire" fans outwardly at the cathode ends to produce the curved aspect of the detector, and the legs of the meander are small in cross-section and very closely spaced whereby a spatial resolution of about 50 .mu.m can be achieved. All of the other performance characteristics are about as good or better than conventional position sensitive proportional counter type detectors. Count rates of up to 40,000 counts per second with 0.5 .mu.s shaping time constants are achieved.

  17. Highly Sensitive Electro-Optic Modulators

    SciTech Connect

    DeVore, Peter S

    2015-10-26

    There are very important diagnostic and communication applications that receive faint electrical signals to be transmitted over long distances for capture. Optical links reduce bandwidth and distance restrictions of metal transmission lines; however, such signals are only weakly imprinted onto the optical carrier, resulting in low fidelity transmission. Increasing signal fidelity often necessitates insertion of radio-frequency (RF) amplifiers before the electro-optic modulator, but (especially at high frequencies) RF amplification results in large irreversible distortions. We have investigated the feasibility of a Sensitive and Linear Modulation by Optical Nonlinearity (SALMON) modulator to supersede RF-amplified modulators. SALMON uses cross-phase modulation, a manifestation of the Kerr effect, to enhance the modulation depth of an RF-modulated optical wave. This ultrafast process has the potential to result in less irreversible distortions as compared to a RF-amplified modulator due to the broadband nature of the Kerr effect. Here, we prove that a SALMON modulator is a feasible alternative to an RFamplified modulator, by demonstrating a sensitivity enhancement factor greater than 20 and significantly reduced distortion.

  18. High sensitivity ancilla assisted nanoscale DC magnetometry

    NASA Astrophysics Data System (ADS)

    Liu, Yixiang; Ajoy, Ashok; Marseglia, Luca; Saha, Kasturi; Cappellaro, Paola

    2016-05-01

    Sensing slowly varying magnetic fields are particularly relevant to many real world scenarios, where the signals of interest are DC or close to static. Nitrogen Vacancy (NV) centers in diamond are a versatile platform for such DC magnetometry on nanometer length scales. Using NV centers, the standard technique for measuring DC magnetic fields is via the Ramsey protocol, where sensitivities can approach better than 1 μ T/vHz, but are limited by the sensor fast dephasing time T2*. In this work we instead present a method of sensing DC magnetic fields that is intrinsically limited by the much longer T2 coherence time. The method exploits a strongly-coupled ancillary nuclear spin to achieve high DC field sensitivities potentially exceeding that of the Ramsey method. In addition, through this method we sense the perpendicular component of the DC magnetic field, which in conjunction with the parallel component sensed by the Ramsey method provides a valuable tool for vector DC magnetometry at the nanoscale.

  19. An Airborne Observing Campaign of an Announced Small Asteroid Impact for High Fidelity Impact Modeling Validation

    NASA Astrophysics Data System (ADS)

    Jenniskens, P. M. M.; Grinstead, J. H.

    2015-12-01

    High fidelity modeling of an asteroid impact requires a known size, mass, shape, entry orientation, entry speed, entry angle, time and location of entry, and material properties of the impacting asteroid. Much of that information can be gathered from small asteroids on an impact trajectory with Earth while they are on approach, given sufficient warning time. That makes small asteroid impacts uniquely suited for collecting data to validate such models. One-meter sized asteroids impact Earth about once a week, 4-meter sized asteroids impact once a year. So far, only asteroid 2008 TC3 was observed in space, characterized prior to impact, and then recovered in part as meteorites on the ground. The next TC3-like impact could provide more warming time to study the impact in detail. Close to 70 percent of all asteroid impacts on Earth occur over the ocean. Hence, small asteroid impact observations require an instrumented airborne platform to take a multi-disciplined research team to the right location at the right time. From a safe 100-km distance, the impact would be observed low enough in the sky to study the process of fragmentation that dictates at which altitude the kinetic energy is deposited that can cause an airburst. Constraints on radiative heating, ablation rate, and fragmentation processes can be obtained from measuring the air plasma emission escaping the shock, elemental atom line emissions and excitation conditions, pressure broadening, and deceleration in the plane of the known trajectory. It is also possible to measure wake, lightcurve and air plasma emission line intensities early in flight that can be used to evaluate the presence of regolith and the internal cohesion of asteroids. The main element abundance (asteroid composition) can be measured for individual fragments, while CN-band emission can point to the presence of organic matter. Such information will help constrain the meteorite type if no meteorites can be recovered in an over

  20. High Spatial Resolution Airborne Multispectral Thermal Infrared Remote Sensing Data for Analysis of Urban Landscape Characteristics

    NASA Technical Reports Server (NTRS)

    Quattrochi, Dale A.; Luvall, Jeffrey C.; Estes, Maurice G., Jr.; Arnold, James E. (Technical Monitor)

    2000-01-01

    We have used airborne multispectral thermal infrared (TIR) remote sensing data collected at a high spatial resolution (i.e., 10m) over several cities in the United States to study thermal energy characteristics of the urban landscape. These TIR data provide a unique opportunity to quantify thermal responses from discrete surfaces typical of the urban landscape and to identify both the spatial arrangement and patterns of thermal processes across the city. The information obtained from these data is critical to understanding how urban surfaces drive or force development of the Urban Heat Island (UHI) effect, which exists as a dome of elevated air temperatures that presides over cities in contrast to surrounding non-urbanized areas. The UHI is most pronounced in the summertime where urban surfaces, such as rooftops and pavement, store solar radiation throughout the day, and release this stored energy slowly after sunset creating air temperatures over the city that are in excess of 2-4'C warmer in contrast with non-urban or rural air temperatures. The UHI can also exist as a daytime phenomenon with surface temperatures in downtown areas of cities exceeding 38'C. The implications of the UHI are significant, particularly as an additive source of thermal energy input that exacerbates the overall production of ground level ozone over cities. We have used the Airborne Thermal and Land Applications Sensor (ATLAS), flown onboard a Lear 23 jet aircraft from the NASA Stennis Space Center, to acquire high spatial resolution multispectral TIR data (i.e., 6 bandwidths between 8.2-12.2 (um) over Huntsville, Alabama, Atlanta, Georgia, Baton Rouge, Louisiana, Salt Lake City, Utah, and Sacramento, California. These TIR data have been used to produce maps and other products, showing the spatial distribution of heating and cooling patterns over these cities to better understand how the morphology of the urban landscape affects development of the UHI. In turn, these data have been used

  1. Hydrological characterization of a riparian vegetation zone using high resolution multi-spectral airborne imagery

    NASA Astrophysics Data System (ADS)

    Akasheh, Osama Z.

    The Middle Rio Grande River (MRGR) is the main source of fresh water for the state of New Mexico. Located in an arid area with scarce local water resources, this has led to extensive diversions of river water to supply the high demand from municipalities and irrigated agricultural activities. The extensive water diversions over the last few decades have affected the composition of the native riparian vegetation by decreasing the area of cottonwood and coyote willow and increasing the spread of invasive species such as Tamarisk and Russian Olives, harmful to the river system, due to their high transpiration rates, which affect the river aquatic system. The need to study the river hydrological processes and their relation with its health is important to preserve the river ecosystem. To be able to do that a detailed vegetation map was produced using a Utah State University airborne remote sensing system for 286 km of river reach. Also a groundwater model was built in ArcGIS environment which has the ability to estimate soil water potential in the root zone and above the modeled water table. The Modified Penman-Monteith empirical equation was used in the ArcGIS environment to estimate riparian vegetation ET, taking advantage of the detailed vegetation map and spatial soil water potential layers. Vegetation water use per linear river reach was estimated to help decision makers to better manage and release the amount of water that keeps a sound river ecosystem and to support agricultural activities.

  2. Vibration amplitude and induced temperature limitation of high power air-borne ultrasonic transducers.

    PubMed

    Saffar, Saber; Abdullah, Amir

    2014-01-01

    The acoustic impedances of matching layers, their internal loss and vibration amplitude are the most important and influential parameters in the performance of high power airborne ultrasonic transducers. In this paper, the optimum acoustic impedances of the transducer matching layers were determined by using a genetic algorithm, the powerful tool for optimizating domain. The analytical results showed that the vibration amplitude increases significantly for low acoustic impedance matching layers. This enhancement is maximum and approximately 200 times higher for the last matching layer where it has the same interface with the air than the vibration amplitude of the source, lead zirconate titanate-pizo electric while transferring the 1 kW is desirable. This large amplitude increases both mechanical failure and temperature of the matching layers due to the internal loss of the matching layers. It has analytically shown that the temperature in last matching layer with having the maximum vibration amplitude is high enough to melt or burn the matching layers. To verify suggested approach, the effect of the amplitude of vibration on the induced temperature has been investigated experimentally. The experimental results displayed good agreement with the theoretical predictions. PMID:23664304

  3. Development of the NASA High-Altitude Imaging Wind and Rain Airborne Profiler

    NASA Technical Reports Server (NTRS)

    Li, Lihua; Heymsfield, Gerald; Carswell, James; Schaubert, Dan; McLinden, Matthew; Vega, Manuel; Perrine, Martin

    2011-01-01

    The scope of this paper is the development and recent field deployments of the High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP), which was funded under the NASA Instrument Incubator Program (IIP) [1]. HIWRAP is a dual-frequency (Ka- and Ku-band), dual-beam (300 and 400 incidence angles), conical scanning, Doppler radar system designed for operation on the NASA high-altitude (65,000 ft) Global Hawk Unmanned Aerial System (UAS). It utilizes solid state transmitters along with a novel pulse compression scheme that results in a system with compact size, light weight, less power consumption, and low cost compared to radars currently in use for precipitation and Doppler wind measurements. By combining measurements at Ku- and Ka-band, HIWRAP is able to image winds through measuring volume backscattering from clouds and precipitation. In addition, HIWRAP is also capable of measuring surface winds in an approach similar to SeaWinds on QuikScat. To this end, HIWRAP hardware and software development has been completed. It was installed on the NASA WB57 for instrument test flights in March, 2010 and then deployed on the NASA Global Hawk for supporting the Genesis and Rapid Intensification Processes (GRIP) field campaign in August-September, 2010. This paper describes the scientific motivations of the development of HIWRAP as well as system hardware, aircraft integration and flight missions. Preliminary data from GRIP science flights is also presented.

  4. Application of high spatial resolution airborne hyperspectral remote sensing data in thematic information extraction

    NASA Astrophysics Data System (ADS)

    Xu, Hong-gen; Ma, Hong-chao; Li, De-ren; Song, Yan

    2006-10-01

    The airborne hyperspectral remote sensing data, such as PHI, OMIS, has the virtues of high spatial and spectral resolution. Hence, from the view of target classification we can consider that it can provide the ability of discriminating targets more detailedly than other data. So it's important to extract thematic information and update database using this kind of data. Whereas, the hyperspectral data has abundant bands and high between-band correlation, the traditional classification methods such as maximum likelihood classifier (MLC) and spectral angle mapper (SAM) have performed poorly in thematic information extraction. For this reason, we present a new method for thematic information extraction with hyperspectral remote sensing data. We perform classification by means of combining the self-organizing map (SOM) neural network which is considered as full-pixel technique with linear spectral mixture analysis (LSMA) which is considered as mixed-pixel technique. The SOM neural network is improved from some aspects to classify the pure data and find the mixed data. And then the mixed data are unmixed and classified by LSMA. The result of experiment shows that we can have the better performance in thematic information extraction with PHI by this means.

  5. Highly sensitive silicon microreactor for catalyst testing

    SciTech Connect

    Henriksen, Toke R.; Hansen, Ole; Olsen, Jakob L.; Vesborg, Peter; Chorkendorff, Ib

    2009-12-15

    A novel microfabricated chemical reactor for highly sensitive measurements of catalytic activity and surface kinetics is presented. The reactor is fabricated in a silicon chip and is intended for gas-phase reactions at pressures ranging from 0.1 to 5.0 bar. A high sensitivity is obtained by directing the entire gas flow through the catalyst bed to a mass spectrometer, thus ensuring that nearly all reaction products are present in the analyzed gas flow. Although the device can be employed for testing a wide range of catalysts, the primary aim of the design is to allow characterization of model catalysts which can only be obtained in small quantities. Such measurements are of significant fundamental interest but are challenging because of the low surface areas involved. The relationship between the reaction zone gas flow and the pressure in the reaction zone is investigated experimentally. A corresponding theoretical model is presented, and the gas flow through an on-chip flow-limiting capillary is predicted to be in the intermediate regime. The experimental data for the gas flow are found to be in good agreement with the theoretical model. At typical experimental conditions, the total gas flow through the reaction zone is around 3x10{sup 14} molecules s{sup -1}, corresponding to a gas residence time in the reaction zone of about 11 s. To demonstrate the operation of the microreactor, CO oxidation on low-area platinum thin film circles is employed as a test reaction. Using temperature ramping, it is found that platinum catalysts with areas as small as 15 {mu}m{sup 2} are conveniently characterized with the device.

  6. Face Transplantation in a Highly Sensitized Recipient.

    PubMed

    Chandraker, Anil; Arscott, Ramon; Murphy, George; Lian, Christine; Bueno, Ericka; Marty, Francisco; Rennke, Helmut; Milford, Edgar; Tullius, Stefan; Pomahac, Bodhan

    2016-05-01

    Face transplantation was performed in a highly sensitized recipient with positive preoperative crossmatch and subsequent antibody-mediated rejection. The recipient was a 45-year-old female with extensive conventional reconstructions after chemical burns over the majority of the body. Residual quality of life and facial functions were poor. Levels of circulating anti-human leukocyte antigen (HLA) antibodies were high, and panel reactive antibody score was 98%. A potential donor was identified; however, with positive T and B cell flow crossmatches. The transplant team proceeded with face transplantation from this donor, under tailored immune suppression and with available salvage options. The operation was successful. Plasmapheresis and induction immune suppression (i.e., thymoglobulin followed by mycophenolate mofetil, tacrolimus, and steroids) were provided. Five days later, there was significant facial swelling, rising anti-HLA antibody titers, and unprecedented evidence of C4d deposits on skin. High doses of steroids and thymoglobulin were provided; however, rejection increased such that by day 19 it was diagnosed grade III in the BANFF scale. After stopping thymoglobulin because of serum sickness, combination therapy of plasmapheresis, eculizumab, bortezomib, and alemtuzumab was provided. HLA antibody levels decreased while swelling and redness improved. At 3 months, there were no longer signs of rejection on biopsy. PMID:27168576

  7. Airborne fungi in low and high allergic prevalence child care centers

    NASA Astrophysics Data System (ADS)

    Zuraimi, M. S.; Fang, L.; Tan, T. K.; Chew, F. T.; Tham, K. W.

    Fungi exposure has been linked to asthma and allergies among children. To determine the association between fungal exposure and wheeze and rhinitis symptoms, we examined concentrations of culturable indoor and outdoor fungi of various aerodynamic sizes in low and high allergic prevalence child care centers (CCCs) in Singapore. Environmental parameters were also performed for air temperature, relative humidity and ventilation rates, while information on CCC characteristics was collected via an inspection. Most commonly recovered fungi were Penicillium, Aspergillus, Geotrichum, Cladosporium and sterile mycelia with Geotrichum and sterile mycelia amounting to an average of 71.5% of the total airborne culturable fungi studied. Indoor and outdoor total culturable fungi concentrations and those in the size range of 1.1-3.3 μm were significantly higher in high allergic prevalence CCCs. When fungal types/genera were compared, indoor and outdoor Geotrichum and sterile mycelia of aerodynamic sizes 1.1-3.3 μm were found to be significantly elevated in high allergic prevalence CCCs. Indeed, average geometric mean diameters ( Dg, ave) of indoor and outdoor culturable fungi were consistently smaller in CCCs with high prevalence of allergies than those with low prevalence. We found significant associations of higher fungal concentrations, especially those with smaller aerodynamic sizes in CCCs situated near parks. There were no differences in fungal levels between CCCs with respect to their dampness profile mainly due to high CCC ventilation rates. Since particle size is a factor that determines where a fungi particle deposits in the respiratory tract, this study provides useful information in the etiology of wheeze and rhinitis symptoms among the CCC attending children.

  8. Mixed Layer Heights Derived from the NASA Langley Research Center Airborne High Spectral Resolution Lidar

    NASA Technical Reports Server (NTRS)

    Scarino, Amy J.; Burton, Sharon P.; Ferrare, Rich A.; Hostetler, Chris A.; Hair, Johnathan W.; Obland, Michael D.; Rogers, Raymond R.; Cook, Anthony L.; Harper, David B.; Fast, Jerome; Dasilva, Arlindo; Benedetti, Angela

    2012-01-01

    The NASA airborne High Spectral Resolution Lidar (HSRL) has been deployed on board the NASA Langley Research Center's B200 aircraft to several locations in North America from 2006 to 2012 to aid in characterizing aerosol properties for over fourteen field missions. Measurements of aerosol extinction (532 nm), backscatter (532 and 1064 nm), and depolarization (532 and 1064 nm) during 349 science flights, many in coordination with other participating research aircraft, satellites, and ground sites, constitute a diverse data set for use in characterizing the spatial and temporal distribution of aerosols, as well as properties and variability of the Mixing Layer (ML) height. We describe the use of the HSRL data collected during these missions for computing ML heights and show how the HSRL data can be used to determine the fraction of aerosol optical thickness within and above the ML, which is important for air quality assessments. We describe the spatial and temporal variations in ML heights found in the diverse locations associated with these experiments. We also describe how the ML heights derived from HSRL have been used to help assess simulations of Planetary Boundary Layer (PBL) derived using various models, including the Weather Research and Forecasting Chemistry (WRF-Chem), NASA GEOS-5 model, and the ECMWF/MACC models.

  9. A Nadir-adjusted Airborne Multi Spectral Imaging System (NAMSIS) for high-resolution remote sensing of carbon fluxes

    NASA Astrophysics Data System (ADS)

    Jiang, Z.; Scott, S.; Rahman, A. F.

    2012-12-01

    Satellite remote sensing is widely used in vegetation monitoring, water stress detection and carbon cycle modeling. However, image pixels from high temporal resolution satellite sensors (such as MODIS) have coarse spatial resolution, much larger than the canopies they are supposed to characterize. An alternative solution for on-demand high spatial resolution remote sensing is sensors onboard low-flying aircrafts. Airborne remote sensing has been traditionally used in crop management studies. In this presentation we demonstrate the application of a relatively low-cost airborne sensor system with customized spectral band combinations for studying forest carbon fluxes. Our team has developed an Inertia Measurement Unit (IMU) controlled automated system to detach aircraft movements (pitch and roll) and engine vibration from the six-band programmable imager, in order to maintain the sensor at nadir view at all times during the flight. Flight lines are configured by a GPS-controleld system to simulate MODIS pixels. A feature-based algorithm is used to automatically generate a mosaic of individual images along the flight lines. This algorithm eliminates the need to mosiac and georeference images manually. An empirical line method is used to calculate reflectance from the raw data. Images from this airborne system produce reflectance values that are comparable with MODIS reflectance product. These high spatial resolution (~0.5 m) images deliver detailed information about tree species and phenological conditions within each MODIS pixel, and thus permit a high resolution spatio-temporal assessment of forest carbon fluxes.

  10. Forest Stand Segmentation Using Airborne LIDAR Data and Very High Resolution Multispectral Imagery

    NASA Astrophysics Data System (ADS)

    Dechesne, Clément; Mallet, Clément; Le Bris, Arnaud; Gouet, Valérie; Hervieu, Alexandre

    2016-06-01

    Forest stands are the basic units for forest inventory and mapping. Stands are large forested areas (e.g., ≥ 2 ha) of homogeneous tree species composition. The accurate delineation of forest stands is usually performed by visual analysis of human operators on very high resolution (VHR) optical images. This work is highly time consuming and should be automated for scalability purposes. In this paper, a method based on the fusion of airborne laser scanning data (or lidar) and very high resolution multispectral imagery for automatic forest stand delineation and forest land-cover database update is proposed. The multispectral images give access to the tree species whereas 3D lidar point clouds provide geometric information on the trees. Therefore, multi-modal features are computed, both at pixel and object levels. The objects are individual trees extracted from lidar data. A supervised classification is performed at the object level on the computed features in order to coarsely discriminate the existing tree species in the area of interest. The analysis at tree level is particularly relevant since it significantly improves the tree species classification. A probability map is generated through the tree species classification and inserted with the pixel-based features map in an energetical framework. The proposed energy is then minimized using a standard graph-cut method (namely QPBO with α-expansion) in order to produce a segmentation map with a controlled level of details. Comparison with an existing forest land cover database shows that our method provides satisfactory results both in terms of stand labelling and delineation (matching ranges between 94% and 99%).

  11. On-Orbit Calibration of a Multi-Spectral Satellite Satellite Sensor Using a High Altitude Airborne Imaging Spectrometer

    NASA Technical Reports Server (NTRS)

    Green, R. O.; Shimada, M.

    1996-01-01

    Earth-looking satellites must be calibrated in order to quantitatively measure and monitor components of land, water and atmosphere of the Earth system. The inevitable change in performance due to the stress of satellite launch requires that the calibration of a satellite sensor be established and validated on-orbit. A new approach to on-orbit satellite sensor calibration has been developed using the flight of a high altitude calibrated airborne imaging spectrometer below a multi-spectral satellite sensor.

  12. Highly sensitive direct conversion ultrasound interferometer

    NASA Astrophysics Data System (ADS)

    Svitelskiy, Oleksiy; Grossmann, John; Suslov, Alexey

    2015-03-01

    Being invented more than fifty years ago, the ultrasonic pulse-echo technique has proven itself as a valuable and indispensable non-destructive tool to explore elastic properties of materials in engineering and scientific tasks. We propose a new design for the instrument based on mass-produced integral microchips. In our design the radiofrequency echo-pulse signal is processed by AD8302 RF gain and phase detector (www.analog.com).Its phase output is linearly proportional to the phase difference between the exciting and response signals. The gain output is proportional to the log of the ratio of amplitudes of the received to the exciting signals. To exclude the non-linear fragments and to enable exploring large phase changes, we employ parallel connection of two detectors, fed by in-phase and quadrature signals respectively. The instrument allowed us exploring phase transitions with precision of ΔV / V ~10-7 (V is the ultrasound speed). The high sensitivity of the logarithmic amplifiers embedded into AD8302 requires good grounding and screening of the receiving circuitry.

  13. Demonstration of high sensitivity laser ranging system

    NASA Technical Reports Server (NTRS)

    Millar, Pamela S.; Christian, Kent D.; Field, Christopher T.

    1994-01-01

    We report on a high sensitivity semiconductor laser ranging system developed for the Gravity and Magnetic Earth Surveyor (GAMES) for measuring variations in the planet's gravity field. The GAMES laser ranging instrument (LRI) consists of a pair of co-orbiting satellites, one which contains the laser transmitter and receiver and one with a passive retro-reflector mounted in an drag-stabilized housing. The LRI will range up to 200 km in space to the retro-reflector satellite. As the spacecraft pair pass over the spatial variations in the gravity field, they experience along-track accelerations which change their relative velocity. These time displaced velocity changes are sensed by the LRI with a resolution of 20-50 microns/sec. In addition, the pair may at any given time be drifting together or apart at a rate of up to 1 m/sec, introducing a Doppler shift into the ranging signals. An AlGaAs laser transmitter intensity modulated at 2 GHz and 10 MHz is used as fine and medium ranging channels. Range is measured by comparing phase difference between the transmit and received signals at each frequency. A separate laser modulated with a digital code, not reported in this paper, will be used for coarse ranging to unambiguously determine the distance up to 200 km.

  14. Using High-Resolution Airborne Remote Sensing to Study Aerosol Near Clouds

    NASA Technical Reports Server (NTRS)

    Levy, Robert; Munchak, Leigh; Mattoo, Shana; Marshak, Alexander; Wilcox, Eric; Gao, Lan; Yorks, John; Platnick, Steven

    2016-01-01

    The horizontal space in between clear and cloudy air is very complex. This so-called twilight zone includes activated aerosols that are not quite clouds, thin cloud fragments that are not easily observable, and dying clouds that have not quite disappeared. This is a huge challenge for satellite remote sensing, specifically for retrieval of aerosol properties. Identifying what is cloud versus what is not cloud is critically important for attributing radiative effects and forcings to aerosols. At the same time, the radiative interactions between clouds and the surrounding media (molecules, surface and aerosols themselves) will contaminate retrieval of aerosol properties, even in clear skies. Most studies on aerosol cloud interactions are relevant to moderate resolution imagery (e.g. 500 m) from sensors such as MODIS. Since standard aerosol retrieval algorithms tend to keep a distance (e.g. 1 km) from the nearest detected cloud, it is impossible to evaluate what happens closer to the cloud. During Studies of Emissions, Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS), the NASA ER-2 flew with the enhanced MODIS Airborne Simulator (eMAS), providing MODIS-like spectral observations at high (50 m) spatial resolution. We have applied MODIS-like aerosol retrieval for the eMAS data, providing new detail to characterization of aerosol near clouds. Interpretation and evaluation of these eMAS aerosol retrievals is aided by independent MODIS-like cloud retrievals, as well as profiles from the co-flying Cloud Physics Lidar (CPL). Understanding aerosolcloud retrieval at high resolution will lead to better characterization and interpretation of long-term, global products from lower resolution (e.g.MODIS) satellite retrievals.

  15. The NASA Airborne Tropical TRopopause EXperiment (ATTREX):High-Altitude Aircraft Measurements in the Tropical Western Pacific

    NASA Technical Reports Server (NTRS)

    Jensen, E. J.; Pfister, L.; Jordan, D. E.; Bui, T. V.; Ueyama, R.; Singh, H. B.; Lawson, P.; Thornberry, T.; Diskin, G.; McGill, M.; Pittman, J.; Atlas, E.; Kim, J.

    2016-01-01

    The February through March 2014 deployment of the NASA Airborne Tropical TRopopause EXperiment (ATTREX) provided unique in situ measurements in the western Pacific Tropical Tropopause Layer (TTL). Six flights were conducted from Guam with the long-range, high-altitude, unmanned Global Hawk aircraft. The ATTREX Global Hawk payload provided measurements of water vapor, meteorological conditions, cloud properties, tracer and chemical radical concentrations, and radiative fluxes. The campaign was partially coincident with the CONTRAST and CAST airborne campaigns based in Guam using lower-altitude aircraft The ATTREX dataset is being used for investigations of TTL cloud, transport, dynamical, and chemical processes as well as for evaluation and improvement of global-model representations of TTL processes.

  16. Optical design of high resolution and large format CCD airborne remote sensing camera on unmanned aerial vehicle

    NASA Astrophysics Data System (ADS)

    Qian, Yixian; Cheng, Xiaowei; Shao, Jie

    2010-11-01

    Unmanned aerial vehicle remote sensing (UAVRS) is lower in cost, flexible on task arrangement and automatic and intelligent in application, it has been used widely for mapping, surveillance, reconnaissance and city planning. Airborne remote sensing missions require sensors with both high resolution and large fields of view, large format CCD digital airborne imaging systems are now a reality. A refractive system was designed to meet the requirements with the help of code V software, It has a focal length of 150mm, F number of 5.6, waveband of 0.45~0.7um, and field of view reaches 20°. It is shown that the value of modulation transfer function is higher than 0.5 at 55lp/mm, distortion is less than 0.1%, image quality reaches the diffraction limit. The system with large format CCD and wide field can satisfy the demand of the wide ground overlay area and high resolution. The optical system with simpler structure, smaller size and lighter weight, can be used in airborne remote sensing.

  17. Imaging and radiometric performance simulation for a new high-performance dual-band airborne reconnaissance camera

    NASA Astrophysics Data System (ADS)

    Seong, Sehyun; Yu, Jinhee; Ryu, Dongok; Hong, Jinsuk; Yoon, Jee-Yeon; Kim, Sug-Whan; Lee, Jun-Ho; Shin, Myung-Jin

    2009-05-01

    In recent years, high performance visible and IR cameras have been used widely for tactical airborne reconnaissance. The process improvement for efficient discrimination and analysis of complex target information from active battlefields requires for simultaneous multi-band measurement from airborne platforms at various altitudes. We report a new dual band airborne camera designed for simultaneous registration of both visible and IR imagery from mid-altitude ranges. The camera design uses a common front end optical telescope of around 0.3m in entrance aperture and several relay optical sub-systems capable of delivering both high spatial resolution visible and IR images to the detectors. The camera design is benefited from the use of several optical channels packaged in a compact space and the associated freedom to choose between wide (~3 degrees) and narrow (~1 degree) field of view. In order to investigate both imaging and radiometric performances of the camera, we generated an array of target scenes with optical properties such as reflection, refraction, scattering, transmission and emission. We then combined the target scenes and the camera optical system into the integrated ray tracing simulation environment utilizing Monte Carlo computation technique. Taking realistic atmospheric radiative transfer characteristics into account, both imaging and radiometric performances were then investigated. The simulation results demonstrate successfully that the camera design satisfies NIIRS 7 detection criterion. The camera concept, details of performance simulation computation, the resulting performances are discussed together with future development plan.

  18. Monitoring Ephemeral Streams Using Airborne Very High Resolution Multispectral Remote Sensing in Arid Environments

    NASA Astrophysics Data System (ADS)

    Hamada, Y.; O'Connor, B. L.

    2012-12-01

    Development in arid environments often results in the loss and degradation of the ephemeral streams that provide habitat and critical ecosystem functions such as water delivery, sediment transport, and groundwater recharge. Quantification of these ecosystem functions is challenging because of the episodic nature of runoff events in desert landscapes and the large spatial scale of watersheds that potentially can be impacted by large-scale development. Low-impact development guidelines and regulatory protection of ephemeral streams are often lacking due to the difficulty of accurately mapping and quantifying the critical functions of ephemeral streams at scales larger than individual reaches. Renewable energy development in arid regions has the potential to disturb ephemeral streams at the watershed scale, and it is necessary to develop environmental monitoring applications for ephemeral streams to help inform land management and regulatory actions aimed at protecting and mitigating for impacts related to large-scale land disturbances. This study focuses on developing remote sensing methodologies to identify and monitor impacts on ephemeral streams resulting from the land disturbance associated with utility-scale solar energy development in the desert southwest of the United States. Airborne very high resolution (VHR) multispectral imagery is used to produce stereoscopic, three-dimensional landscape models that can be used to (1) identify and map ephemeral stream channel networks, and (2) support analyses and models of hydrologic and sediment transport processes that pertain to the critical functionality of ephemeral streams. Spectral and statistical analyses are being developed to extract information about ephemeral channel location and extent, micro-topography, riparian vegetation, and soil moisture characteristics. This presentation will demonstrate initial results and provide a framework for future work associated with this project, for developing the necessary

  19. Separating Dust Mixtures and Other External Aerosol Mixtures Using Airborne High Spectral Resolution Lidar Data

    NASA Astrophysics Data System (ADS)

    Burton, S. P.; Ferrare, R. A.; Vaughan, M.; Hostetler, C. A.; Rogers, R. R.; Hair, J. W.; Cook, A. L.; Harper, D. B.

    2013-12-01

    Knowledge of aerosol type is important for source attribution and for determining the magnitude and assessing the consequences of aerosol radiative forcing. The NASA Langley Research Center airborne High Spectral Resolution Lidar (HSRL-1) has acquired considerable datasets of both aerosol extensive parameters (e.g. aerosol optical depth) and intensive parameters (e.g. aerosol depolarization ratio, lidar ratio) that can be used to infer aerosol type. An aerosol classification methodology has been used extensively to classify HSRL-1 aerosol measurements of different aerosol types including dust, smoke, urban pollution, and marine aerosol. However, atmospheric aerosol is frequently not a single pure type, but instead occurs as a mixture of types, and this mixing affects the optical and radiative properties of the aerosol. Here we present a comprehensive and unified set of rules for characterizing external mixtures using several key aerosol intensive parameters: extinction-to-backscatter ratio (i.e. lidar ratio), backscatter color ratio, and depolarization ratio. Our mixing rules apply not just to the scalar values of aerosol intensive parameters, but to multi-dimensional normal distributions with variance in each measurement dimension. We illustrate the applicability of the mixing rules using examples of HSRL-1 data where mixing occurred between different aerosol types, including advected Saharan dust mixed with the marine boundary layer in the Caribbean Sea and locally generated dust mixed with urban pollution in the Mexico City surroundings. For each of these cases we infer a time-height cross section of mixing ratio along the flight track and we partition aerosol extinction into portions attributed to the two pure types. Since multiple aerosol intensive parameters are measured and included in these calculations, the techniques can also be used for cases without significant depolarization (unlike similar work by earlier researchers), and so a third example of a

  20. High-Rate Data-Capture for an Airborne Lidar System

    NASA Technical Reports Server (NTRS)

    Valett, Susan; Hicks, Edward; Dabney, Philip; Harding, David

    2012-01-01

    A high-rate data system was required to capture the data for an airborne lidar system. A data system was developed that achieved up to 22 million (64-bit) events per second sustained data rate (1408 million bits per second), as well as short bursts (less than 4 s) at higher rates. All hardware used for the system was off the shelf, but carefully selected to achieve these rates. The system was used to capture laser fire, single-photon detection, and GPS data for the Slope Imaging Multi-polarization Photo-counting Lidar (SIMPL). However, the system has applications for other laser altimeter systems (waveform-recording), mass spectroscopy, xray radiometry imaging, high-background- rate ranging lidar, and other similar areas where very high-speed data capture is needed. The data capture software was used for the SIMPL instrument that employs a micropulse, single-photon ranging measurement approach and has 16 data channels. The detected single photons are from two sources those reflected from the target and solar background photons. The instrument is non-gated, so background photons are acquired for a range window of 13 km and can comprise many times the number of target photons. The highest background rate occurs when the atmosphere is clear, the Sun is high, and the target is a highly reflective surface such as snow. Under these conditions, the total data rate for the 16 channels combined is expected to be approximately 22 million events per second. For each photon detection event, the data capture software reads the relative time of receipt, with respect to a one-per-second absolute time pulse from a GPS receiver, from an event timer card with 0.1-ns precision, and records that information to a RAID (Redundant Array of Independent Disks) storage device. The relative time of laser pulse firings must also be read and recorded with the same precision. Each of the four event timer cards handles the throughput from four of the channels. For each detection event, a flag is

  1. Analytical sensitivity of air samplers based on uniform point-source exposure to airborne Porcine reproductive and respiratory syndrome virus and swine influenza virus

    PubMed Central

    Hermann, Joseph R.; Zimmerman, Jeffrey J.

    2008-01-01

    Research and surveillance activities involving airborne pathogens rely on the capture and enumeration of pathogens suspended in aerosols. The objective of this study was to estimate the analytical sensitivity (detection threshold) of each of 4 air samplers for Porcine reproductive and respiratory syndrome virus (PRRSV) and swine influenza virus (SIV). In a 5-min sampling period under controlled conditions, the analytical sensitivity of the AGI-30 (Ace Glass, Vineland, New Jersey, USA), AGI-4 (Ace Glass), SKC BioSampler (SKC, Eighty Four, Pennsylvania, USA), and Midwest Micro-Tek sampler (Midwest Micro-Tek, Brookings, South Dakota, USA) was calculated at 1 × 101.1, 1 × 101.3, 1 × 101.1, and 1 × 101.2 median tissue culture infectious dose (TCID50) equivalents for PRRSV and 1 × 101.4, 1 × 101.1, 1 × 101.6, and 1 × 101.2 TCID50 equivalents for SIV [per 60 L (5-min sampling period)]. Despite marked differences in sampler design, no statistically significant difference in analytical sensitivity was detected between the samplers for collection of artificially produced aerosols containing cell-culture-propagated PRRSV or SIV. PMID:19086377

  2. THE AIRBORNE CULTURABLE MICROBIAL ECOLOGY OF SEVEN FEEDYARDS IN THE HIGH PLAINS OF TEXAS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Concentrated animal feeding operations (CAFO) produce a large amount of manure that can impact the environment if not managed properly. Environmental issues at CAFO include odor, pathogens, endotoxins (ET), and dust. The role of ET and pathogens with dust emissions was investigated. Airborne microbi...

  3. Airborne gravity is here

    SciTech Connect

    Hammer, S.

    1982-01-11

    After 20 years of development efforts, the airborne gravity survey has finally become a practical exploration method. Besides gravity data, the airborne survey can also collect simultaneous, continuous records of high-precision magneticfield data as well as terrain clearance; these provide a topographic contour map useful in calculating terrain conditions and in subsequent planning and engineering. Compared with a seismic survey, the airborne gravity method can cover the same area much more quickly and cheaply; a seismograph could then detail the interesting spots.

  4. Using High-Resolution Airborne LiDAR-Data for Landslide Mapping in the Eastern Alps

    NASA Astrophysics Data System (ADS)

    Kamp, N.

    2012-04-01

    Due to the increasing frequency of natural disasters like floods and landslides, the active remote sensing technique LiDAR (Light Detection and Ranging), has become a topic of great interest to the Federal State Government of Styria, Federal Republic of Austria. In a perennial project from 2008 to 2012 high-resolution 3D Airborne LiDAR Data of the Province of Styria, an area about 16.000km2 in south-eastern Austria were collected. These data were processed to create Digital Terrain Models (DTM) and Digital Surface Models (DSM) at 1m resolution with a vertical accuracy of 15 [cm] and a positional accuracy of 40 [cm]. High resolution DTMs can be used in different geo-related applications like geomorphological mapping or natural hazard mapping. DTMs show because of its high accuracy various natural and anthropogenic terrain features such as erosion scarps, alluvial fans, landslides, old creeks, topographic edges and karstforms, as well as walking paths and roads and in addition to that LiDAR data allows the detection and outlining of these different geomorphological and anthropogenic features with the help of ArcGIS 10 geoprocessing and analysing techniques, mathematical, statistical and image processing methods and the open source scripting language Python. As a result complex workflows and new geoprocessing tools can be implemented in an ArcGIS 10 workspace and are provided as easy to use toolbox contents. The landslide phenomena take in centre stage of the research work of the author. Thereby the main focus is targeted on sliding movements out of soils and bedrock. Factors like gravity take effect on slope stability directly and cause complex mass movements with a downslope directed, gliding movement of bed- and/or loose-rock as well as soil material. In this paper the author presents the result of her master thesis, an automatic ArcGIS 10 landslide mapping tool using high-resolution LiDAR data in the rock masses of the Eastern Alps (Province of Styria, Austria

  5. A case of high noise sensitivity

    NASA Astrophysics Data System (ADS)

    Murata, M.; Sakamoto, H.

    1995-10-01

    A case of noise sensitivity with a five-year follow-up period is reported. The patient was a 34-year-old single man who was diagnosed as having psychosomatic disorder triggered by two stressful life events in rapid succession with secondary hypersensitivity to noise. Hypersensitivity to light and cold also developed later in the clinical course. The auditory threshold was within the normal range. The discomfort threshold as a measure of the noise sensitivity secondary to mental illness was measured repeatedly using test tone of audiometry. The discomfort threshold varied depending upon his mental status, ranging from 40-50 dB in the comparatively poorer mental state to 70-95 dB in the relatively good mental state. The features of noise sensitivity, including that secondary to mental illness, are discussed.

  6. Biological monitoring of airborne pollution

    SciTech Connect

    Ditz, D.W. )

    1990-01-01

    Common plants such as grasses, mosses, and even goldenrod may turn out to have a new high-tech role as monitors of airborne pollution from solid waste incinerators. Certain plants that respond to specific pollutants can provide continuous surveillance of air quality over long periods of time: they are bio-indicators. Other species accumulate pollutants and can serve as sensitive indicators of pollutants and of food-chain contamination: they are bio-accumulators. Through creative use of these properties, biological monitoring can provide information that cannot be obtained by current methods such as stack testing.

  7. Applying modified high resolution airborne LiDAR DTM for floodplain mapping

    NASA Astrophysics Data System (ADS)

    Vetter, M.; Jochem, A.; Franke, M.; Schöberl, F.; Stötter, J.; Werthmann, M.

    2009-04-01

    Today, airborne LiDAR derived digital terrain models (DTM) are used in the research context and various scientific disciplines. In hydrology such high resolution DTMs are used for computing flood simulations, calculating roughness maps, floodplain mapping, etc. The presented approach outlines the strength of a LiDAR derived DTM (1m) in comparison to a photogrammetric derived DTM (10m). By implementing an interpolated river bed model, which is derived by using terrestrial measured river cross sections and hence modifying the high resolution DTM for hydraulic task floodplain mapping and modeling routines, could be improved. The river bed interpolation routine includes an automatic bridge detection algorithm to delete bridge pillars in the relevant river cross sections. Furthermore, the position of riverbanks, which are a contributing factor in the field of hydraulic modeling and influence the results of the hydraulic simulations, can be detected. Once the DTM is modified, river cross profiles can be extracted directly on each position along the river axis and can be used as input for hydraulic models. In this study the software HEC-RAS is used to calculate different floodplain areas on the basis of the HQ30, HQ100 and HQ200 flood scenarios, which are calibrated on key data of the flood in August 2005. The comparison of the floodplain area in the city of Innsbruck (Tyrol, Austria), modeled on the basis of a modified LiDAR derived DTM, with those from the HORA study (Hochwasserrisikozonierung Austria), shows remarkable differences. These differences result from (i) the different hydraulic modeling methods and (ii) the used DTMs, which HORA does not consider flood protection measures. The results show that the resolution of the used DTM is the determining factor for modeling adequate floodplain areas whereas the applied hydraulic model has secondary effects. The grade of accuracy attained by this approach is reflected by the numbers ,of flooding affected buildings (e

  8. A high sensitive phosphor for dosimetric applications

    NASA Astrophysics Data System (ADS)

    Kore, Bhushan P.; Dhoble, N. S.; Lochab, S. P.; Dhoble, S. J.

    2015-06-01

    In this study a novel TL phosphor CaMg3(SO4)4:Dy3+ was prepared by acid distillation method. The TL response of this phosphor towards γ-rays and carbon ion beam was tested. Good dosimetric glow curve was observed which is stable against both the type of radiations. The CaMg3(SO4)4:Dy3+ phosphor doped with 0.2 mol% of Dy3+, irradiated with γ-ray shows nearly equal sensitivity to that of commercially available CaSO4:Dy TLD phosphor whereas 3.5 times more sensitivity than CaSO4:Dy, when irradiated with carbon ion beam. The change in glow peak intensities and glow peak temperature with variation in irradiation species and energy of ion beam is discussed here. The effect of these on trapping parameters is also illustrated.

  9. High altitude airborne remote sensing mission using the advanced microwave precipitation radiometer (AMPR)

    NASA Technical Reports Server (NTRS)

    Galliano, J.; Platt, R. H.; Spencer, Roy; Hood, Robbie

    1991-01-01

    The advanced microwave precipitation radiometer (AMPR) is an airborne multichannel imaging radiometer used to better understand how the earth's climate structure works. Airborne data results from the October 1990 Florida thunderstorm mission in Jacksonville, FL, are described. AMPR data on atmospheric precipitation in mesoscale storms were retrieved at 10.7, 19.35, 37.1, and 85.5 GHz onboard the ER-2 aircraft at an altitude of 20 km. AMPR's three higher-frequency data channels were selected to operate at the same frequencies as the spaceborne special sensor microwave/imager (SSM/I) presently in orbit. AMPR uses two antennas to receive the four frequencies: the lowest frequency channel uses a 9.7-in aperture lens antennas, while the three higher-frequency channels share a separate 5.3-in aperture lens antenna. The radiometer's temperature resolution performance is summarized.

  10. High-resolution topographic change detection of an active earthflow using airborne and terrestrial LiDAR, Mill Gulch, California

    NASA Astrophysics Data System (ADS)

    Murphy, B. P.; DeLong, S.

    2011-12-01

    In landscapes where airborne laser swath mapping (ALSM) exists, terrestrial laser scanning (TLS) can be used to update high-resolution topographic models for quantification of landscape change. At Mill Gulch in northern California, we scanned an active earthflow using TLS in 2011 that had also been imaged by ALSM in 2003 and 2007. In order to evaluate change at the sub-meter level between the ALSM and TLS data, we generated a custom, 30 cm resolution ALSM digital elevation model (DEM), employed geographic transformations to align the disparate datasets, and refined the vertical alignment using an unaltered road surface. We then conducted vegetation removal from the TLS data, gridded it to 30 cm, and produced detailed maps of topographic evolution. Previous work comparing the 2003 and 2007 ALSM data indicated that this earthflow translated blocks of material as much as 5 m/yr and that significant material was removed by the channel at the toe of the earthflow, leading to a net elevation decrease across the earthflow. Over the last four years, the earthflow has experienced overall rotational movement leading to distinct failure planes in the source area with elevations decreasing as much as 3.75 m, while the toe aggraded up to 2.5 m. Maximum translation rates in the transport zone have decreased to 3.5 m/yr and very little material was removed by the channel. Early analysis indicates a slight increase in the net volume of the earthflow and an average elevation increase of 0.05 m between 2007 and 2011. It is possible this is the result of any number of factors, including the failure of TLS to adequately measure the thalweg depth of supra-flow gullies and depths of tension fractures, higher sensitivity to grasses in TLS data, decreased material density (and concomitant volumetric increase) due to tension fracturing, the swelling of clays and increased pore water pressure in the earthflow. However, it is also reasonable that this result reflects minor systematic error

  11. Thermal management of closed computer modules utilizing high density circuitry. [in Airborne Information Management System

    NASA Technical Reports Server (NTRS)

    Hoadley, A. W.; Porter, A. J.

    1990-01-01

    This paper presents data on a preliminary analysis of the thermal dynamic characteristics of the Airborne Information Management System (AIMS), which is a continuing design project at NASA Dryden. The analysis established the methods which will be applied to the actual AIMS boards as they become available. The paper also describes the AIMS liquid cooling system design and presents a thermodynamic computer model of the AIMS cooling system, together with an experimental validation of this model.

  12. Low-noise small SWaP SWIR imagers for light-starved high-sensitivity applications

    NASA Astrophysics Data System (ADS)

    Delamere, Michael

    2014-06-01

    High Sensitivity Megapixel and VGA shortwave IR imagers are presented. The imagers have 1280×1024 and 640×512 resolution FPAs with 12.5 μm pitch. The associated camera electronics are designed to optimize small SWaP and performance for a variety of applications including man-portable and airborne systems. Performance characterization of both these imagers is presented showing low-noise, high dynamic range capability suitable for challenging operational environments including light-starved and urban environments as well as a variety of industrial applications.

  13. High sensitivity leak detection method and apparatus

    DOEpatents

    Myneni, G.R.

    1994-09-06

    An improved leak detection method is provided that utilizes the cyclic adsorption and desorption of accumulated helium on a non-porous metallic surface. The method provides reliable leak detection at superfluid helium temperatures. The zero drift that is associated with residual gas analyzers in common leak detectors is virtually eliminated by utilizing a time integration technique. The sensitivity of the apparatus of this disclosure is capable of detecting leaks as small as 1 [times] 10[sup [minus]18] atm cc sec[sup [minus]1]. 2 figs.

  14. High sensitivity leak detection method and apparatus

    DOEpatents

    Myneni, Ganapatic R.

    1994-01-01

    An improved leak detection method is provided that utilizes the cyclic adsorption and desorption of accumulated helium on a non-porous metallic surface. The method provides reliable leak detection at superfluid helium temperatures. The zero drift that is associated with residual gas analyzers in common leak detectors is virtually eliminated by utilizing a time integration technique. The sensitivity of the apparatus of this disclosure is capable of detecting leaks as small as 1.times.10.sup.-18 atm cc sec.sup.-1.

  15. USE OF WATER RAMAN EMISSION TO CORRECT AIRBORNE LASER FLUOROSENSOR DATA FOR EFFECTS OF WATER OPTICAL ATTENUATION

    EPA Science Inventory

    Airborne laser fluorosensor measurements of fluorophore concentrations in surface waters are highly sensitive to interference from changes in optical attenuation. This interference can be eliminated by normalizing the fluorescence signal with the concurrent water Raman signal. In...

  16. A high sensitive phosphor for dosimetric applications

    SciTech Connect

    Kore, Bhushan P. Dhoble, S. J.; Dhoble, N. S.; Lochab, S. P.

    2015-06-24

    In this study a novel TL phosphor CaMg{sub 3}(SO{sub 4}){sub 4}:Dy{sup 3+} was prepared by acid distillation method. The TL response of this phosphor towards γ-rays and carbon ion beam was tested. Good dosimetric glow curve was observed which is stable against both the type of radiations. The CaMg{sub 3}(SO{sub 4}){sub 4}:Dy{sup 3+} phosphor doped with 0.2 mol% of Dy{sup 3+}, irradiated with γ-ray shows nearly equal sensitivity to that of commercially available CaSO{sub 4}:Dy TLD phosphor whereas 3.5 times more sensitivity than CaSO{sub 4}:Dy, when irradiated with carbon ion beam. The change in glow peak intensities and glow peak temperature with variation in irradiation species and energy of ion beam is discussed here. The effect of these on trapping parameters is also illustrated.

  17. The Caltech airborne submillimeter SIS receiver

    NASA Technical Reports Server (NTRS)

    Zmuidzinas, Jonas; Carlstrom, J.; Miller, D.; Ugras, N. G.

    1995-01-01

    We have constructed a sensitive submillimeter receiver for the NASA Kuiper Airborne Observatory (KAO) which at present operates in the 500-750 GHz band. The DSB receiver noise temperature is about 5 h nu/k(sub B) over the 500-700 GHz range. This receiver has been used to detect H2O(18)O, HCl, and CH in interstellar molecular clouds, and also to search for C(+) emission from the highly redshifted galaxy (z = 2.3) IRAS 10214.

  18. CMOS Amperometric ADC With High Sensitivity, Dynamic Range and Power Efficiency for Air Quality Monitoring.

    PubMed

    Li, Haitao; Boling, C Sam; Mason, Andrew J

    2016-08-01

    Airborne pollutants are a leading cause of illness and mortality globally. Electrochemical gas sensors show great promise for personal air quality monitoring to address this worldwide health crisis. However, implementing miniaturized arrays of such sensors demands high performance instrumentation circuits that simultaneously meet challenging power, area, sensitivity, noise and dynamic range goals. This paper presents a new multi-channel CMOS amperometric ADC featuring pixel-level architecture for gas sensor arrays. The circuit combines digital modulation of input currents and an incremental Σ∆ ADC to achieve wide dynamic range and high sensitivity with very high power efficiency and compact size. Fabricated in 0.5 [Formula: see text] CMOS, the circuit was measured to have 164 dB cross-scale dynamic range, 100 fA sensitivity while consuming only 241 [Formula: see text] and 0.157 [Formula: see text] active area per channel. Electrochemical experiments with liquid and gas targets demonstrate the circuit's real-time response to a wide range of analyte concentrations. PMID:27352395

  19. Airborne Multi-wavelength High Spectral Resolution Lidar for Process Studies and Assessment of Future Satellite Remote Sensing Concepts

    NASA Astrophysics Data System (ADS)

    Hostetler, C. A.; Ferrare, R. A.; Hair, J. W.; Cook, A. L.; Harper, D. B.; Mack, T. L.; Hare, R. J.; Cleckner, C. S.; Rogers, R.; Mueller, D.; Chemyakin, E.; Burton, S. P.; Obland, M. D.; Scarino, A. J.; Cairns, B.; Russell, P. B.; Redemann, J.; Shinozuka, Y.; Schmid, B.; Berg, L. K.; Fast, J. D.; Flynn, C. J.

    2012-12-01

    NASA Langley recently developed the world's first airborne multi-wavelength high spectral resolution lidar (HSRL). This lidar employs the HSRL technique at 355 and 532 nm to make independent, unambiguous retrievals of aerosol extinction and backscatter. It also employs the standard backscatter technique at 1064 nm and is polarization-sensitive at all three wavelengths. This instrument, dubbed HSRL-2 (the second-generation HSRL developed by NASA Langley), is a prototype for the lidar on NASA's planned Aerosols-Clouds-Ecosystems (ACE) mission. HSRL-2 completed its first science mission in July 2012, the Two-Column Aerosol Project (TCAP) conducted by the Department of Energy (DOE) in Hyannis, MA. TCAP presents an excellent opportunity to assess some of the remote sensing concepts planned for ACE: HSRL-2 was deployed on the Langley King Air aircraft with another ACE-relevant instrument, the NASA GISS Research Scanning Polarimeter (RSP), and flights were closely coordinated with the DOE's Gulfstream-1 aircraft, which deployed a variety of in situ aerosol and trace gas instruments and the new Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR). The DOE also deployed their Atmospheric Radiation Measurement Mobile Facility and their Mobile Aerosol Observing System at a ground site located on the northeastern coast of Cape Cod for this mission. In this presentation we focus on the capabilities, data products, and applications of the new HSRL-2 instrument. Data products include aerosol extinction, backscatter, depolarization, and optical depth; aerosol type identification; mixed layer depth; and range-resolved aerosol microphysical parameters (e.g., effective radius, index of refraction, single scatter albedo, and concentration). Applications include radiative closure studies, studies of aerosol direct and indirect effects, investigations of aerosol-cloud interactions, assessment of chemical transport models, air quality studies, present (e.g., CALIPSO

  20. Using Airborne High Spectral Resolution Lidar Data to Evaluate Combined Active Plus Passive Retrievals of Aerosol Extinction Profiles

    NASA Technical Reports Server (NTRS)

    Burton, S. P.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. W.; Kittaka, C.; Vaughn, M. A.; Remer, L. A.

    2010-01-01

    We derive aerosol extinction profiles from airborne and space-based lidar backscatter signals by constraining the retrieval with column aerosol optical thickness (AOT), with no need to rely on assumptions about aerosol type or lidar ratio. The backscatter data were acquired by the NASA Langley Research Center airborne High Spectral Resolution Lidar (HSRL) and by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite. The HSRL also simultaneously measures aerosol extinction coefficients independently using the high spectral resolution lidar technique, thereby providing an ideal data set for evaluating the retrieval. We retrieve aerosol extinction profiles from both HSRL and CALIOP attenuated backscatter data constrained with HSRL, Moderate-Resolution Imaging Spectroradiometer (MODIS), and Multiangle Imaging Spectroradiometer column AOT. The resulting profiles are compared with the aerosol extinction measured by HSRL. Retrievals are limited to cases where the column aerosol thickness is greater than 0.2 over land and 0.15 over water. In the case of large AOT, the results using the Aqua MODIS constraint over water are poorer than Aqua MODIS over land or Terra MODIS. The poorer results relate to an apparent bias in Aqua MODIS AOT over water observed in August 2007. This apparent bias is still under investigation. Finally, aerosol extinction coefficients are derived from CALIPSO backscatter data using AOT from Aqua MODIS for 28 profiles over land and 9 over water. They agree with coincident measurements by the airborne HSRL to within +/-0.016/km +/- 20% for at least two-thirds of land points and within +/-0.028/km +/- 20% for at least two-thirds of ocean points.

  1. The effects of cage design on airborne allergens and endotoxin in animal rooms: high-volume measurements with an ion-charging device.

    PubMed

    Platts-Mills, James; Custis, Natalie; Kenney, Alice; Tsay, Amy; Chapman, Martin; Feldman, Sanford; Platts-Mills, Thomas

    2005-03-01

    Respiratory symptoms related to both endotoxins and animal allergens continue to be an important cause of occupational disease for animal technicians and scientists working with rodents. Better sampling methods for airborne allergens and endotoxin are needed to help standardize compliance with federal occupational health regulations. Using an ion-charging device, we sampled 20 mouse rooms and four rat rooms at the University of Virginia, along with 43 domestic living rooms in houses in the Charlottesville area with at least one cat or dog. The use of filter tops on cages corresponds to a 50-fold reduction in mean levels of both airborne allergens (P < 0.001) and endotoxin (P < 0.001). The use of vented cages with filtered exhaust ports was associated with additional reductions. However, the mean airborne endotoxin level in all rooms using filter tops without a filtered exhaust port on the cages was significantly lower (P = 0.003) than the level in domestic living rooms. Our results for maximum airborne allergens or endotoxin are comparable with previous reports. However, the sensitivity of the technique allows an accurate assessment of low-level exposure, which makes it possible to evaluate the effect of cage designs. In addition, this approach allows direct comparison with results for airborne allergen and endotoxin in domestic homes. The results could allow a more consistent approach to the application of occupational health guidelines. PMID:15773770

  2. Linking terrace geomorphology and canopy characteristics in the Peruvian Amazon using high resolution airborne remote sensing (Invited)

    NASA Astrophysics Data System (ADS)

    Chadwick, K.; Asner, G. P.

    2013-12-01

    The Peruvian Amazon is home to over half a million square kilometers of forest, nearly three quarters of which is supported by terrace landforms with variable histories. Characteristics of these terrace ecosystems have been contrasted with neighboring floodplain systems along riverine transportation corridors, but the ecological complexity within these terrace landscapes has remained largely unexplored. Airborne remote measurements provide an opportunity to consider the relationship between forest canopy characteristics and geomorphic gradients at high resolution over large spatial extents. In 2011 the Carnegie Airborne Observatory (CAO) was used to map a large section of intact lowland humid tropical forest in the southwestern Peruvian Amazon, including over nine thousand hectares of terrace forest. The CAO collected high-fidelity imaging spectroscopy data with its Visible-Shortwave Imaging Spectrometer (VSWIR) and digital elevation and canopy structure data with its high-resolution dual waveform LiDAR. These data, supplemented with field data collection, were used to quantify relationships between forest canopy traits and geomorphic gradients. Results suggest that both spectral properties of the canopy with known relationships to canopy chemistry, including pigment and nutrient concentrations, and canopy structural traits, including vegetation height and leaf area, are associated with geomorphic characteristics of this terrace landscape.

  3. High-Sensitivity GaN Microchemical Sensors

    NASA Technical Reports Server (NTRS)

    Son, Kyung-ah; Yang, Baohua; Liao, Anna; Moon, Jeongsun; Prokopuk, Nicholas

    2009-01-01

    Systematic studies have been performed on the sensitivity of GaN HEMT (high electron mobility transistor) sensors using various gate electrode designs and operational parameters. The results here show that a higher sensitivity can be achieved with a larger W/L ratio (W = gate width, L = gate length) at a given D (D = source-drain distance), and multi-finger gate electrodes offer a higher sensitivity than a one-finger gate electrode. In terms of operating conditions, sensor sensitivity is strongly dependent on transconductance of the sensor. The highest sensitivity can be achieved at the gate voltage where the slope of the transconductance curve is the largest. This work provides critical information about how the gate electrode of a GaN HEMT, which has been identified as the most sensitive among GaN microsensors, needs to be designed, and what operation parameters should be used for high sensitivity detection.

  4. Fabrication of High Sensitive Immunochromato Kit Using Au Colloid

    NASA Astrophysics Data System (ADS)

    Okamoto, Koji

    Au colloid have characteristics of surface plasmon resonance with absorption at 500 nm~600 nm wavelength. Surface on the citric acid Au colloid can be conjugated with protein eg. antibody. Various particle size of Au colloid makes it high sensitive immunochromato as diagnostics. High sensitive immunochromato will be useful for application of cancer marker eg. prostate specific antigen and influenza early diagnosis.

  5. Comparison of Aerosol Classification From Airborne High Spectral Resolution Lidar and the CALIPSO Vertical Feature Mask

    NASA Technical Reports Server (NTRS)

    Burton, Sharon P.; Ferrare, Rich A.; Omar, Ali H.; Vaughan, Mark A.; Rogers, Raymond R.; Hostetler, Chris a.; Hair, Johnathan W.; Obland, Michael D.; Butler, Carolyn F.; Cook, Anthony L.; Harper, David B.

    2012-01-01

    Knowledge of aerosol composition and vertical distribution is crucial for assessing the impact of aerosols on climate. In addition, aerosol classification is a key input to CALIOP aerosol retrievals, since CALIOP requires an inference of the lidar ratio in order to estimate the effects of aerosol extinction and backscattering. In contrast, the NASA airborne HSRL-1 directly measures both aerosol extinction and backscatter, and therefore the lidar ratio (extinction-to-backscatter ratio). Four aerosol intensive properties from HSRL-1 are combined to infer aerosol type. Aerosol classification results from HSRL-1 are used here to validate the CALIOP aerosol type inferences.

  6. The influence of sex, allergic rhinitis, and test system on nasal sensitivity to airborne irritants: a pilot study.

    PubMed Central

    Shusterman, D; Murphy, M A; Balmes, J

    2001-01-01

    "Nasal irritant sensitivity" is an important construct in environmental health science; functional measures, however, lack standardization. We performed duplicate measures of nasal irritant perceptual acuity on 16 subjects (evenly divided by sex and seasonal allergy status) using two different test compounds: carbon dioxide (CO2) (detection) and n-propanol (localization). The a priori hypotheses included a) allergic rhinitics will display lower perceptual thresholds than nonrhinitics; b) females will display lower perceptual thresholds than males; and c) estimates of perceptual acuity using the two test systems will be positively correlated. We obtained CO2 detection thresholds using an ascending concentration series, presenting 3-sec pulses of CO2, paired with air in random order, by nasal cannula. We obtained localization thresholds by simultaneously presenting stimuli (ascending concentrations of n-propanol vapor in air) and blanks (saturated water vapor in air) to opposite nostrils, with laterality randomized. In terms of test-retest reliability, individual replicate measures for CO2 detection thresholds correlated more closely than did the localization thresholds of volatile organic compounds (VOC) (r = 0.65 and r = 0.60, respectively). As an intertest comparison, log-transformed individual mean CO2 and VOC measures were positively correlated with an r of 0.63 (p < 0.01). In univariate analyses, sex predicted both log-transformed CO2 and VOC thresholds (females being more "sensitive"; p < 0.05 and 0.001, respectively). Nasal allergies predicted sensory testing results only in the multivariate analysis, and then only for VOC localization (p < 0.05). The question of population variation in nasal irritant sensitivity (as well as the generalizability of results across test compounds) deserves further attention. PMID:11171519

  7. Linearization strategies for high sensitivity magnetoresistive sensors

    NASA Astrophysics Data System (ADS)

    Silva, Ana V.; Leitao, Diana C.; Valadeiro, João; Amaral, José; Freitas, Paulo P.; Cardoso, Susana

    2015-10-01

    Ultrasensitive magnetic field sensors envisaged for applications on biomedical imaging require the detection of low-intensity and low-frequency signals. Therefore linear magnetic sensors with enhanced sensitivity low noise levels and improved field detection at low operating frequencies are necessary. Suitable devices can be designed using magnetoresistive sensors, with room temperature operation, adjustable detected field range, CMOS compatibility and cost-effective production. The advent of spintronics set the path to the technological revolution boosted by the storage industry, in particular by the development of read heads using magnetoresistive devices. New multilayered structures were engineered to yield devices with linear output. We present a detailed study of the key factors influencing MR sensor performance (materials, geometries and layout strategies) with focus on different linearization strategies available. Furthermore strategies to improve sensor detection levels are also addressed with best reported values of ˜40 pT/√Hz at 30 Hz, representing a step forward the low field detection at room temperature.

  8. Towards a Better Understanding of Forest Biophysical Parameters - Combining High Fidelity Simulations, Airborne Waveform Lidar, and Terrestrial Lidar Sensing

    NASA Astrophysics Data System (ADS)

    van Aardt, J. A.; Kelbe, D.; Romanczyk, P.; van Leeuwen, M.; Cawse-Nicholson, K.; Krause, K.; Kampe, T. U.

    2015-12-01

    The science community has come a long way from traditional, 2D imaging approaches to the assessment of ecosystem structure, function and composition. For example, waveform- (wlidar) and terrestrial lidar systems (TLS) present us with exciting opportunities for detailed, accurate and precise, and scalable structural characterization of vegetation. wlidar and TLS generally can be regarded as complementary i.e., airborne wlidar typically digitizes the entire backscattered energy profile at high spatial and vertical resolutions, while TLS samples dense 3D point clouds of the bottom-up vegetation structure. Research teams at Rochester Institute of Technology (RIT) have been collaborating with the National Ecological Observation Network (NEON) to assess vegetation structure and variation in the Pacific-Southwest (San Joaquin Experimental Range and Soaproot Saddle sites, CA) and Northeast (Harvard Forest, MA) domains. The teams collected airborne small-footprint wlidar data and in-situ TLS data for these sites and is taking a two-tiered (top-down and bottom-up) approach to forest structural assessment. We will present our work where we (i) studied wlidar signal attenuation throughout the canopy in a simulation environment - the attenuation correction factor was linearly proportional to the sum of the area under the proceeding Gaussians - and (ii) used the fine-scale stem structure extracted via TLS to reconstruct complex, but realistic, 3D forest environments for refined simulation studies. These studies indicate that we can potentially assess vegetation canopies remotely using a vertically-stratified approach with wlidar and use rapid-scan TLS technology to calibrate models predicated upon synoptic airborne systems. Other outputs of our approaches can be used for typical forest inventory, ecological parameter extraction, and new algorithm validation.

  9. Eugenic metal-free sensitizers with double anchors for high performance dye-sensitized solar cells.

    PubMed

    Hung, Wei-I; Liao, You-Ya; Lee, Ting-Hui; Ting, Yu-Chien; Ni, Jen-Shyang; Kao, Wei-Siang; Lin, Jiann T; Wei, Tzu-Chien; Yen, Yung-Sheng

    2015-02-01

    A series of new phenothiazine-based dyes (HL5-HL7) with double acceptors/anchors have been synthesized and used as the sensitizers for highly efficient dye-sensitized solar cells (DSSCs). Among them, the HL7-based cell exhibits the best efficiency of 8.32% exceeding the N719-based cell (7.35%) by ∼13%. PMID:25555237

  10. Monitoring of Pd in airborne particulates by solid sampling high-resolution continuum source electrothermal atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Atilgan, Semin; Akman, Suleyman; Baysal, Asli; Bakircioglu, Yasemin; Szigeti, Tamás; Óvári, Mihály; Záray, Gyula

    2012-04-01

    An analytical method has been developed for determination of palladium in PM2.5 fractions of urban airborne particulate matter by solid sampling high-resolution continuum source electrothermal atomic absorption spectrometry. For the optimization of the experimental conditions, a road dust certified reference material (BCR-723) was used. The influence of pyrolysis and atomization temperatures, the amount of sample introduced into the graphite furnace and the addition of acids, surfactants and modifiers on the analytical signal of Pd were investigated. The limit of detection, calculated based on three times the standard deviations of analytical signals obtained during the atomization of 10 blank filter pieces, was 0.07 pg/m3. Since the amount of solid certified reference material introduced into the graphite furnace was about 50-2000 times lower than those required in order to obtain the certified value, the precision was relatively poor. This analytical method was applied for investigation of urban airborne particulate matter collected onto quartz fiber filters by high-volume aerosol samplers in the city center of Istanbul (Turkey) and Budapest (Hungary). The measured Pd concentrations changed in the range of 0.22-0.64 and 0.25-0.86 pg/m3 in Istanbul and Budapest, respectively.

  11. Novel high-sensitivity fluorescence polarization reader

    NASA Astrophysics Data System (ADS)

    Hoyt, Clifford C.; Levenson, Richard M.; Banks, Peter

    2001-05-01

    We have developed a new fluorescence polarization (FP) reader suitable for high-throughput screening (HST) and ultra-HTS whose assay-performance and sample-throughput are both considerably improved over present state-of-the-art instrumentation. The SymmetryTM reader possesses a number of features that differ from conventional HTS FP readers. These include: laser-based excitation, liquid crystal polarization optics that rapidly and accurately measure polarization states; and CCD detectors to capture emission from multiple wells. We show that the performance in assays relevant to the drug discovery process, such as G- protein coupled receptor-based assays, is significantly enhanced due to a dramatic improvement in precision. Furthermore, the CCD-detection system used can substantially improve sample throughput compared to sequential readers while maintaining high performance.

  12. High sensitivity accelerometers for high performance seismic attenuators

    NASA Astrophysics Data System (ADS)

    Bertolini, A.; de Salvo, R.; Fidecaro, F.; Francesconi, M.; Sannibale, V.; Takamori, A.

    2000-06-01

    We present concepts and features of a new horizontal accelerometer whose mechanical design and machining process aim to improve the sensitivity in the frequency region between 10 mHz and 1 Hz. The expected sensitivity, less than 10-11 m/s2/Hz around 100 mHz, is a couple of orders of magnitude below the state of art limits. This accelerometer could be integrated in the active control of the LIGO II mirror seismic isolators. .

  13. A compact PTR-ToF-MS instrument for airborne measurements of VOCs at high spatio-temporal resolution

    NASA Astrophysics Data System (ADS)

    Müller, M.; Mikoviny, T.; Feil, S.; Haidacher, S.; Hanel, G.; Hartungen, E.; Jordan, A.; Märk, L.; Mutschlechner, P.; Schottkowsky, R.; Sulzer, P.; Crawford, J. H.; Wisthaler, A.

    2014-06-01

    Herein, we report on the development of a compact proton-transfer-reaction time-of-flight mass spectrometer for airborne measurements of volatile organic compounds (VOCs). The new instrument resolves isobaric ions with a mass resolving power (m/Δm) of ~ 1000, provides accurate m/z measurements (Δm < 3 mDa), records full mass spectra at 1 Hz and thus overcomes some of the major analytical deficiencies of quadrupole-MS based airborne instruments. 1 Hz detection limits for biogenic VOCs (isoprene, α-pinene), aromatic VOCs (benzene, toluene, xylenes) and ketones (acetone, methyl ethyl ketone) range from 0.05 to 0.12 ppbV, making the instrument well-suited for fast measurements in the continental boundary layer. The instrument detects and quantifies VOCs in locally confined plumes (< 1km) which improves our capability of characterizing emission sources and atmospheric processing within plumes. A deployment during the NASA 2013 DISCOVER-AQ mission generated high vertical and horizontal resolution in situ data of VOCs and ammonia for validation of satellite retrievals and chemistry transport models.

  14. A compact PTR-ToF-MS instrument for airborne measurements of volatile organic compounds at high spatiotemporal resolution

    NASA Astrophysics Data System (ADS)

    Müller, M.; Mikoviny, T.; Feil, S.; Haidacher, S.; Hanel, G.; Hartungen, E.; Jordan, A.; Märk, L.; Mutschlechner, P.; Schottkowsky, R.; Sulzer, P.; Crawford, J. H.; Wisthaler, A.

    2014-11-01

    Herein, we report on the development of a compact proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) for airborne measurements of volatile organic compounds (VOCs). The new instrument resolves isobaric ions with a mass resolving power (m/Δm) of ~1000, provides accurate m/z measurements (Δm < 3 mDa), records full mass spectra at 1 Hz and thus overcomes some of the major analytical deficiencies of quadrupole-MS-based airborne instruments. 1 Hz detection limits for biogenic VOCs (isoprene, α total monoterpenes), aromatic VOCs (benzene, toluene, xylenes) and ketones (acetone, methyl ethyl ketone) range from 0.05 to 0.12 ppbV, making the instrument well-suited for fast measurements of abundant VOCs in the continental boundary layer. The instrument detects and quantifies VOCs in locally confined plumes (< 1 km), which improves our capability of characterizing emission sources and atmospheric processing within plumes. A deployment during the NASA 2013 DISCOVER-AQ mission generated high vertical- and horizontal-resolution in situ data of VOCs and ammonia for the validation of satellite retrievals and chemistry transport models.

  15. High sensitivity silicon single nanowire junctionless phototransistor

    NASA Astrophysics Data System (ADS)

    Das, Samaresh; Dhyani, Veerendra; Georgiev, Yordan M.; Williams, David A.

    2016-02-01

    A high-gain photodetector based on junctionless MOSEFT has been presented in this work. Tri-gate junctionless nanowire phototransistors were fabricated on (100) silicon-on-insulator wafers with a buried oxide of thickness 145 nm and top silicon layer of thickness 10 nm. The gate stack consisted of a 10 nm SiO2 dielectric and a 50 nm poly-Si gate electrode. The channel length and doping concentration of junctionless n-MOSFETs was 1 μm and 3 × 1019 cm-3, respectively. The dark current of this device measured at room temperature was less than 1 pA. The measured internal gain of the device was about 35 for 860 nm light illumination. The photocurrent was 300 times larger than the dark current for only 30 nW incident power on the nanowire at 300 mV drain bias.

  16. Fabrication of sensitive high Tc bolometers

    NASA Technical Reports Server (NTRS)

    Nahum, Michael; Verghese, S.; Hu, Qing; Richards, Paul L.; Char, K.; Newman, N.; Sachtjen, Scott A.

    1990-01-01

    The rapid change of resistance with temperature of high quality films of high T sub c superconductors can be used to make resistance thermometers with very low temperature noise. Measurements on c-axis yttrium barium copper oxide (YBCO) films have given a spectral intensity of temperature noise less than 4 times 10(exp -8) K/Hz(exp 1/2) at 10 Hz. Consequently, the opportunity exists to make useful bolometric infrared detectors that operate near 90 K which can be cooled with liquid nitrogen. The fabrication and measurement of two bolometer architectures are discussed. The first is a conventional bolometer which consists of a 3000 A thick YBCO film deposited in situ by laser ablation on top of a 500 A thick SrTiO3 thickness and diced into 1x1 mm(exp 2) bolometer chips. Gold black smoke was used as the radiation absorber. The voltage noise was less than the amplifier noise when the film was current biased. Optical measurements gave an NEP of 5 times 10(exp -11) W/Hz(exp 1/2) at 10 Hz. The second architecture is that of an antenna-coupled microbolometer which consists of a small (5x10 cubic microns) YBCO film deposited directly on a bulk substrate with a low thermal conductance (YSZ) and an impedance matched planar lithographed spiral or log-periodic antenna. This structure is produced by standard photolithographic techniques. Measurements gave an electrical NEP of 4.7 times 10(exp -12) W/Hz(exp 1/2) at 10 kHz. Measurements of the optical efficiency are in progress. The measured performance of both bolometers will be compared to other detectors operating at or above liquid nitrogen temperatures so as to identify potential applications.

  17. High resolution Michelson interferometer for airborne infrared astronomical observations. 1: Concept and performance.

    PubMed

    Baluteau, J P; Anderegg, M; Moorwood, A F; Coron, N; Beckman, J E; Bussoletti, E; Hippelein, H H

    1977-07-01

    A Michelson interferometer has been built for use with the 91-cm telescope on NASA's Gerard P. Kuiper Airborne Observatory primarily to measure ir line emission from H 11 regions. Operation is in the rapid scan mode, and the achievable resolution is 0.02 cm(-1) in the wavelength range from 10 micro to around 300 micro. A minicomputer is used to provide on-line spectrum displays and to control and monitor the instrument performance. The design and use of the instrument is discussed, and a comparison is made between the theoretical performance and that actually achieved on the first flights when measurements of line emission from the Orion nebula and from the atmosphere were made. PMID:20168819

  18. Fourth Airborne Geoscience Workshop

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The focus of the workshop was on how the airborne community can assist in achieving the goals of the Global Change Research Program. The many activities that employ airborne platforms and sensors were discussed: platforms and instrument development; airborne oceanography; lidar research; SAR measurements; Doppler radar; laser measurements; cloud physics; airborne experiments; airborne microwave measurements; and airborne data collection.

  19. High-resolution satellite and airborne thermal infrared imaging of precursory unrest and 2009 eruption of Redoubt Volcano, Alaska

    USGS Publications Warehouse

    Wessels, Rick L.; Vaughan, R. Greg; Patrick, Matthew R.; Coombs, Michelle L.

    2013-01-01

    A combination of satellite and airborne high-resolution visible and thermal infrared (TIR) image data detected and measured changes at Redoubt Volcano during the 2008–2009 unrest and eruption. The TIR sensors detected persistent elevated temperatures at summit ice-melt holes as seismicity and gas emissions increased in late 2008 to March 2009. A phreatic explosion on 15 March was followed by more than 19 magmatic explosive events from 23 March to 4 April that produced high-altitude ash clouds and large lahars. Two (or three) lava domes extruded and were destroyed between 23 March and 4 April. After 4 April, the eruption extruded a large lava dome that continued to grow until at least early July 2009.

  20. High-resolution satellite and airborne thermal infrared imaging of precursory unrest and 2009 eruption at Redoubt Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Wessels, Rick L.; Vaughan, R. Greg; Patrick, Matthew R.; Coombs, Michelle L.

    2013-06-01

    A combination of satellite and airborne high-resolution visible and thermal infrared (TIR) image data detected and measured changes at Redoubt Volcano during the 2008-2009 unrest and eruption. The TIR sensors detected persistent elevated temperatures at summit ice-melt holes as seismicity and gas emissions increased in late 2008 to March 2009. A phreatic explosion on 15 March was followed by more than 19 magmatic explosive events from 23 March to 4 April that produced high-altitude ash clouds and large lahars. Two (or three) lava domes extruded and were destroyed between 23 March and 4 April. After 4 April, the eruption extruded a large lava dome that continued to grow until at least early July 2009.

  1. Levee crest elevation profiles derived from airborne lidar-based high resolution digital elevation models in south Louisiana

    USGS Publications Warehouse

    Palaseanu-Lovejoy, Monica; Thatcher, Cindy A.; Barras, John A.

    2014-01-01

    This study explores the feasibility of using airborne lidar surveys to derive high-resolution digital elevation models (DEMs) and develop an automated procedure to extract levee longitudinal elevation profiles for both federal levees in Atchafalaya Basin and local levees in Lafourche Parish. Generally, the use of traditional manual surveying methods to map levees is a costly and time consuming process that typically produces cross-levee profiles every few hundred meters, at best. The purpose of our paper is to describe and test methods for extracting levee crest elevations in an efficient, comprehensive manner using high resolution lidar generated DEMs. In addition, the vertical uncertainty in the elevation data and its effect on the resultant estimate of levee crest heights is addressed in an assessment of whether the federal levees in our study meet the USACE minimum height design criteria.

  2. Airborne laser

    NASA Astrophysics Data System (ADS)

    Lamberson, Steven E.

    2002-06-01

    The US Air Force Airborne Laser (ABL) is an airborne, megawatt-class laser system with a state-of-the-art atmospheric compensation system to destroy enemy ballistic missiles at long ranges. This system will provide both deterrence and defense against the use of such weapons during conflicts. This paper provides an overview of the ABL weapon system including: the notional operational concept, the development approach and schedule, the overall aircraft configuration, the technologies being incorporated in the ABL, and the risk reduction approach being utilized to ensure program success.

  3. Use of high spectral resolution airborne visible/infrared imaging spectrometer data for geologic mapping: An overview

    NASA Technical Reports Server (NTRS)

    Carrere, Veronique

    1991-01-01

    Specific examples of the use of AVIRIS (Airborne Visible/Infrared Imaging Spectrometer) high spectral resolution data for mapping, alteration related to ore deposition and to hydrocarbon seepage, and alluvial fans are presented. Correction for atmospheric effects was performed using flat field correction, log residuals, and radiative transfer modeling. Minerals of interest (alunite, kaolinite, gypsum, carbonate iron oxides, etc.) were mapped based upon the wavelength position, depth and width of characteristic absorption features. Results were checked by comparing to existing maps, results from other sensors (Thematic Mapper (TM) and TIMS (Thermal Infrared Multispectral Scanner)), and laboratory spectra of samples collected in the field. Alteration minerals were identified and mapped. The signal to noise ratio of acquired AVIRIS data, long to 2.0 microns, was insufficient to map minerals of interest.

  4. High fidelity remote sensing of snow properties from MODIS and the Airborne Snow Observatory: Snowflakes to Terabytes

    NASA Astrophysics Data System (ADS)

    Painter, T.; Mattmann, C. A.; Brodzik, M.; Bryant, A. C.; Goodale, C. E.; Hart, A. F.; Ramirez, P.; Rittger, K. E.; Seidel, F. C.; Zimdars, P. A.

    2012-12-01

    The response of the cryosphere to climate forcings largely determines Earth's climate sensitivity. However, our understanding of the strength of the simulated snow albedo feedback varies by a factor of three in the GCMs used in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, mainly caused by uncertainties in snow extent and the albedo of snow-covered areas from imprecise remote sensing retrievals. Additionally, the Western US and other regions of the globe depend predominantly on snowmelt for their water supply to agriculture, industry and cities, hydroelectric power, and recreation, against rising demand from increasing population. In the mountains of the Upper Colorado River Basin, dust radiative forcing in snow shortens snow cover duration by 3-7 weeks. Extended to the entire upper basin, the 5-fold increase in dust load since the late-1800s results in a 3-week earlier peak runoff and a 5% annual loss of total runoff. The remotely sensed dynamics of snow cover duration and melt however have not been factored into hydrological modeling, operational forecasting, and policymaking. To address these deficiencies in our understanding of snow properties, we have developed and validated a suite of MODIS snow products that provide accurate fractional snow covered area and radiative forcing of dust and carbonaceous aerosols in snow. The MODIS Snow Covered Area and Grain size (MODSCAG) and MODIS Dust Radiative Forcing in Snow (MODDRFS) algorithms, developed and transferred from imaging spectroscopy techniques, leverage the complete MODIS surface reflectance spectrum. The two most critical properties for understanding snowmelt runoff and timing are the spatial and temporal distributions of snow water equivalent (SWE) and snow albedo. We have created the Airborne Snow Observatory (ASO), an imaging spectrometer and scanning LiDAR system, to quantify SWE and snow albedo, generate unprecedented knowledge of snow properties, and provide complete

  5. Fabrication of High Sensitivity Carbon Microcoil Pressure Sensors

    PubMed Central

    Su, Chih-Chung; Li, Chen-Hung; Chang, Neng-Kai; Gao, Feng; Chang, Shuo-Hung

    2012-01-01

    This work demonstrates a highly sensitive pressure sensor that was fabricated using carbon microcoils (CMCs) and polydimethylsiloxane (PDMS). CMCs were grown by chemical vapor deposition using various ratios of Fe-Sn catalytic solution. The pressure sensor has a sandwiched structure, in which the as-grown CMCs were inserted between two PDMS layers. The pressure sensor exhibits piezo-resistivity changes in response to mechanical loading using a load cell system. The yields of the growth of CMCs at a catalyst proportion of Fe:Sn = 95:5 reach 95%. Experimental results show that the sensor achieves a high sensitivity of 0.93%/kPa from the CMC yield of 95%. The sensitivity of the pressure sensor increases with increasing yield of CMCs. The demonstrated pressure sensor shows the advantage of high sensitivity and is suitable for mass production. PMID:23112586

  6. Seasonal variability in airborne bacterial communities at a high elevation site and their relationship to other air studies and to potential sources

    NASA Astrophysics Data System (ADS)

    Bowers, R. M.; Mccubbin, I. B.; Hallar, A. G.; Fierer, N.

    2012-12-01

    Airborne bacteria are a large component of the near-surface atmospheric aerosol; however we know surprisingly little about their spatiotemporal dynamics and even less about their distributions at high-elevation. With this work, we describe seasonal shifts in bacterial abundances, total particle abundances, and bacterial community structure at a high-elevation research station located in Colorado, USA. In addition, we describe the unique composition of these high-elevation airborne bacterial communities as compared to the bacteria commonly observed throughout the lower elevation atmosphere as well as bacteria common to major sources such as leaf surfaces, soils, water bodies and various other surfaces. To address these knowledge gaps, we collected aerosol samples on the rooftop of Storm Peak Laboratory (3200 m ASL) over the course of 2-3 week periods during each of the four calendar seasons. Total bacterial abundances were assessed via flow cytometry, total particle abundances were calculated with an aerodynamic particle sizer, and bacterial communities were characterized using a high-throughput barcoded DNA sequencing approach. The airborne bacterial communities at Storm Peak Lab were then used in a meta-analysis comparing Storm Peak bacteria to other near-surface (lower elevation) bacterial communities and to the communities of likely source environments. Bacterial abundances varied by season, which was similar but not identical to the changes in total particle abundances across the same sampling period. Airborne bacterial community structure varied significantly by season, with the summer communities being the most distinct. Season specific bacterial groups were identified, suggesting that a large proportion of the airborne community may be derived from nearby sources. However following a multi-environment meta-analysis using several air and source derived bacterial community datasets, the high-elevation air communities were the most distinct as compared to the

  7. Multi-wavelength Airborne High Spectral Resolution Lidar Observations of Aerosol Above Clouds in California during DISCOVER-AQ

    NASA Astrophysics Data System (ADS)

    Hostetler, C. A.; Burton, S. P.; Ferrare, R. A.; Rogers, R. R.; Mueller, D.; Chemyakin, E.; Cook, A. L.; Harper, D. B.; Ziemba, L. D.; Beyersdorf, A. J.; Anderson, B. E.

    2013-12-01

    Accurately representing the vertical profile of aerosols is important for determining their radiative impact, which is still one of the biggest uncertainties in climate forcing. Aerosol radiative forcing can be either positive or negative depending on aerosol absorption properties and underlying albedo. Therefore, accurately characterizing the vertical distribution of aerosols, and specifically aerosols above clouds, is vital to understanding climate change. Unlike passive sensors, airborne lidar has the capability to make vertically resolved aerosol measurements of aerosols above and between clouds. Recently, NASA Langley Research Center has built and deployed the world's first airborne multi-wavelength High Spectral Resolution Lidar, HSRL-2. The HSRL-2 instrument employs the HSRL technique to measure extinction at both 355 nm and 532 nm and also measures aerosol depolarization and backscatter at 355 nm, 532 nm and 1064 nm. Additional HSRL-2 data products include aerosol type and range-resolved aerosol microphysical parameters (e.g., effective radius, number concentration, and single scattering albedo). HSRL-2 was deployed in the San Joaquin Valley, California, from January 16 to February 6, 2013, on the DISCOVER-AQ field campaign (Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality). On February 6, the observation region was mostly cloudy, and HSRL-2 saw two distinct aerosol layers above the clouds. One layer was aged boundary-layer pollution located just above cloud top at approximately 1.5 km above sea level. An aged smoke layer was also observed over land and over the ocean at altitudes 4-7 km ASL. In this study, we will show HSRL-2 products for these cases, and compare them with airborne in situ measurements of the 1.5-km layer from a coincident flight of the NASA P3B. We will also compare and contrast the HSRL-2 measurements of these two aerosol layers with each other and the clear-air boundary

  8. An investigation of airborne GPS/INS for high accuracy position and velocity determination

    SciTech Connect

    Sun, H.; Cannon, M.E.; Owen, T.E.; Meindl, M.A.

    1993-12-31

    An airborne test using a differential GPS-INS system in a Twin Otter was conducted by Sandia National Laboratories to assess the feasibility of using the integrated system for cm-level position and cm/s velocity. The INS is a miniaturized ring-laser gyro IMU jointly developed by Sandia and Honeywell while the GPS system consists of the NovAtel GPSCard{trademark}. INS position, velocity and attitude data were computed using Sandia`s SANDAC flight computer system and logged at 4 Hz and GPS data was acquired at a 1 Hz rate. The mission was approximately 2.5 hours in duration and the aircraft reached separations of up to 19 km from the base station. The data was post-processed using a centralized Kalman filter approach in which the double differenced carrier phase measurements are used to update the INS data. The INS position is in turn used to detect and correct GPS carrier phase cycle slips and also to bridge GPS outages. Results are presented for the GPS-only case and also for integrated GPS/INS.

  9. High-precision geometric correction of airborne remote sensing revisited: the multiquadric interpolation

    NASA Astrophysics Data System (ADS)

    Ehlers, Manfred; Fogel, David N.

    1994-12-01

    For a geographic analysis of multispectral scanner data from aircraft and their integration in spatial databases and geographic integration systems (GIS), geometric registration/rectification of the scanner imagery is required as a first step. Usually, one has to rely on global mapping functions such as polynomial equations as provided by most commercial image processing systems. These techniques have been proven to be very effective and accurate for satellite images. However, there are a umber of shortcomings when this method is applied to aircraft data. We see the multiquadric interpolation method as a promising alternative. The multiquadric function was first developed for the interpolation of irregular surfaces. It could be modified, however, to be used for image correction of remotely sensed data. In this form, it is particularly suited for the rectification of remote sensing images of large scale and locally varying geometric distortions. The multiquadric interpolation method yields a perfect fit at the used control points (CPs). With this, it is necessary to withhold independent test points that can be used for accuracy assessment. Within the registration/rectification process, all CPs contribute to the geometric warping of any given pixel in the image. Their effects, however, are weighted inversely to the distances between CPs and the current pixel location. The paper presents the multiquadric interpolation techniques and demonstrates successful application with airborne scanner data.

  10. High sensitivity optical waveguide accelerometer based on Fano resonance.

    PubMed

    Wan, Fenghua; Qian, Guang; Li, Ruozhou; Tang, Jie; Zhang, Tong

    2016-08-20

    An optical waveguide accelerometer based on tunable asymmetrical Fano resonance in a ring-resonator-coupled Mach-Zehnder interferometer (MZI) is proposed and analyzed. A Fano resonance accelerometer has a relatively large workspace of coupling coefficients with high sensitivity, which has potential application in inertial navigation, missile guidance, and attitude control of satellites. Due to the interference between a high-Q resonance pathway and a coherent background pathway, a steep asymmetric line shape is generated, which greatly improves the sensitivity of this accelerometer. The sensitivity of the accelerometer is about 111.75 mW/g. A 393-fold increase in sensitivity is achieved compared with a conventional MZI accelerometer and is approximately equal to the single ring structure. PMID:27556984

  11. The Callaway Plant's airborne tritium sampling cart

    SciTech Connect

    Graham, C.C.; Roselius, R.R. )

    1986-07-01

    The water vapor condensation method for sampling airborne tritium offers significant advantages over other methods, including minimal sample preparation, high sensitivity, and independence from collection efficiency and sample flow rate. However, it does have disadvantages that must be overcome in the design of a sampler. This article describes a cart-mounted, portable airborne tritium sampler used at the Callaway Nuclear Plant that incorporates the advantages of the condensation technique while minimizing its shortcomings. The key elements in the design of the sampler are the use of a refrigerated bath to cool a series of three water vapor collection traps and the use of an optical condensation dew point hygrometer to measure the moisture content of the sample. Design considerations for the proper operation of dew point hygrometers are presented, and the method used to convert due point readings to water vapor content is described.

  12. Near-infrared squaraine co-sensitizer for high-efficiency dye-sensitized solar cells.

    PubMed

    Rao, G Hanumantha; Venkateswararao, A; Giribabu, L; Han, Liyuan; Bedja, Idriss; Gupta, Ravindra Kumar; Islam, Ashraful; Singh, Surya Prakash

    2016-06-01

    A combination of squaraine-based dyes (SPSQ1 and SPSQ2) and a ruthenium-based dye (N3) were chosen as co-sensitizers to construct efficient dye-sensitized solar cells. The co-sensitization of squaraine dyes with N3 enhanced their light-harvesting properties as a result of the broad spectral coverage in the region 350-800 nm. The co-sensitized solar cells based on SPSQ2 + N3 showed the highest short circuit current density of 17.10 mA cm(-2), an open circuit voltage of 0.66 V and a fill factor of 0.73, resulting in the highest power conversion efficiency of 8.2%, which is higher than that of the dye-sensitized solar cells based on the individual SPSQ1 and SPSQ2 dyes. The high power conversion efficiency of SPSQ2 + N3 was ascribed to its good light-harvesting properties, which resulted from its broader incident photon current conversion spectrum than that of the individual dyes. The high electron life time and electron recombination, which were the main causes of the higher efficiency of the device, were successfully analysed and correlated using transient absorption spectrometry and intensity-modulated photovoltage spectrometry. PMID:27167491

  13. Airborne Hydromapping - How high-resolution bathymetric surveys will change the research and work focused on waterbody-related topics

    NASA Astrophysics Data System (ADS)

    Steinbacher, Frank; Baran, Ramona; Dobler, Wolfgang; Aufleger, Markus

    2013-04-01

    Repetitive surveying of inshore waters and coastal zones is becoming more and more essential in order to evaluate water-level dynamics, structural and zonal variations of rivers and riparian areas, river degradation, water flow, reservoir sedimentation, delta growth, as well as coastal processes. This can only be achieved in an effective manner by employing hydrographic airborne laser scanning (hydromapping). A new laser scanner is introduced, which has been specifically designed for the acquisition of high-resolution hydrographic data in order to survey and monitor inland waters and shallow coastal zones. Recently, this scanner has been developed within the framework of an Austrian research cooperation between Riegl LMS and the Unit of Hydraulic Engineering at the University of Innsbruck. We present exemplary measurement results obtained with the compact airborne laser-scanning system during our project work. Along the Baltic Sea coast northeast of Kiel city, northern Germany, we obtained measurement depths up to 8 m under clear-water conditions. Moreover, we detect underwater dune-structures and the accumulation of sediment within groin structures. In contrast, under turbid water conditions we obtained depths of approximately 3 m along the Rhine River at Rheinfelden, German-Swiss border east of Basel city. Nevertheless, we were able to map small-scale and complex morphologic features within a fish ramp or bedrock cliffs. The laser data had been combined with sonar measurements displaying the bathymetry at depths of ca. 2-25 m in order to document comprehensively the actual hydrographic setting after the new construction of the hydropower plant Rheinfelden. In summary, a high-resolution spatial view on the ground of various waterbodies is now possible for the first time with point densities in the usual range of approximately 10-20 points/m². However, the combination of these data with high-resolution aerial (approximately < 5 cm/pixel) or spectral images offers

  14. Highly sensitive bovine serum albumin biosensor based on liquid crystal

    NASA Astrophysics Data System (ADS)

    Sharma, Vikash; Kumar, Ajay; Ganguly, Prasun; Biradar, A. M.

    2014-01-01

    A highly sensitive liquid crystal (LC) based bovine serum albumin (BSA) protein biosensor is designed. A uniform homeotropic alignment of nematic LC was observed in BSA free substrate which changed into homogeneous in presence of BSA. The change in the LC orientation is found to depend strongly on BSA concentration. This change in the LC alignment is attributed to the modification in the surface conditions which is verified by contact angle measurements. We have detected an ultra low concentration (0.5 μg/ml) of BSA. The present study demonstrates the utilization of LC in the realization of high sensitivity biosensors.

  15. Analytical Glycobiology at High Sensitivity: Current Approaches and Directions

    PubMed Central

    Novotny, Milos V.; Alley, William R.; Mann, Benjamin F.

    2013-01-01

    This review summarizes the analytical advances made during the last several years in the structural and quantitative determinations of glycoproteins in complex biological mixtures. The main analytical techniques used in the fields of glycomics and glycoproteomics involve different modes of mass spectrometry and their combinations with capillary separation methods such as microcolumn liquid chromatography and capillary electrophoresis. The needs for high-sensitivity measurements have been emphasized in the oligosaccharide profiling used in the field of biomarker discovery through MALDI mass spectrometry. High-sensitivity profiling of both glycans and glycopeptides from biological fluids and tissue extracts has been aided significantly through lectin preconcentration and the uses of affinity chromatography. PMID:22945852

  16. High-sensitivity SQUIDs with dispersive readout for scanning microscopy

    NASA Astrophysics Data System (ADS)

    Mol, J. M.; Foroughi, F.; Arps, J.; Kammerloher, E.; Bethke, P.; Gibson, G. W., Jr.; Fung, Y. K. K.; Klopfer, B.; Nowack, K.; Kratz, P. A.; Huber, M. E.; Moler, K. A.; Kirtley, J. R.; Bluhm, H.

    2014-03-01

    In a scanning SQUID microscope, the high magnetic flux sensitivity is utilized to image magnetic properties of sample surfaces. As an alternative to the widely used DC SQUIDs, we present Nb SQUIDs for scanning with dispersive microwave readout, featuring significantly higher bandwidth and sensitivity. An on-chip shunt capacitor in parallel with the junction and flux pickup loops forms an LC resonator whose resonance depends on the flux in the SQUID. The readout utilizes a phase-sensitive detection of the reflected drive signal at the SQUID's resonance frequency. Highest sensitivities are achieved by making use of the inherent nonlinearity of the device at high excitation powers. We present a study of the characteristics and noise measurements of our sensors at 4 K. Extrapolations from our results to 300 mK indicate that flux sensitivities as low as 50 nΦ0Hz- 1 / 2 could be possible. Using high-resolution lithography, our sensors promise sub-micron spatial resolution. Integrated into a scanning microscope, they will provide a powerful tool for the study of weak magnetic effects and quantum coherent phenomena. This work was supported by NSF IMR-MIP grant No. 0957616 and the Alfried Krupp von Bohlen und Halbach - Foundation.

  17. Large pi-aromatic molecules as potential sensitizers for highly efficient dye-sensitized solar cells.

    PubMed

    Imahori, Hiroshi; Umeyama, Tomokazu; Ito, Seigo

    2009-11-17

    Recently, dye-sensitized solar cells have attracted much attention relevant to global environmental issues. Thus far, ruthenium(II) bipyridyl complexes have proven to be the most efficient TiO(2) sensitizers in dye-sensitized solar cells. However, a gradual increment in the highest power conversion efficiency has been recognized in the past decade. More importantly, considering that ruthenium is a rare metal, novel dyes without metal or using inexpensive metal are desirable for highly efficient dye-sensitized solar cells. Large pi-aromatic molecules, such as porphyrins, phthalocyanines, and perylenes, are important classes of potential sensitizers for highly efficient dye-sensitized solar cells, owing to their photostability and high light-harvesting capabilities that can allow applications in thinner, low-cost dye-sensitized solar cells. Porphyrins possess an intense Soret band at 400 nm and moderate Q bands at 600 nm. Nevertheless, the poor light-harvesting properties relative to the ruthenium complexes have limited the cell performance of porphyrin-sensitized TiO(2) cells. Elongation of the pi conjugation and loss of symmetry in porphyrins cause broadening and a red shift of the absorption bands together with an increasing intensity of the Q bands relative to that of the Soret band. On the basis of the strategy, the cell performance of porphyrin-sensitized solar cells has been improved intensively by the enhanced light absorption. Actually, some push-pull-type porphyrins have disclosed a remarkably high power conversion efficiency (6-7%) that was close to that of the ruthenium complexes. Phthalocyanines exhibit strong absorption around 300 and 700 nm and redox features that are similar to porphyrins. Moreover, phthalocyanines are transparent over a large region of the visible spectrum, thereby enabling the possibility of using them as "photovoltaic windows". However, the cell performance was poor, owing to strong aggregation and lack of directionality in the

  18. Ecosystem services - from assessements of estimations to quantitative, validated, high-resolution, continental-scale mapping via airborne LIDAR

    NASA Astrophysics Data System (ADS)

    Zlinszky, András; Pfeifer, Norbert

    2016-04-01

    service potential" which is the ability of the local ecosystem to deliver various functions (water retention, carbon storage etc.), but can't quantify how much of these are actually used by humans or what the estimated monetary value is. Due to its ability to measure both terrain relief and vegetation structure in high resolution, airborne LIDAR supports direct quantification of the properties of an ecosystem that lead to it delivering a given service (such as biomass, water retention, micro-climate regulation or habitat diversity). In addition, its high resolution allows direct calibration with field measurements: routine harvesting-based ecological measurements, local biodiversity indicator surveys or microclimate recordings all take place at the human scale and can be directly linked to the local value of LIDAR-based indicators at meter resolution. Therefore, if some field measurements with standard ecological methods are performed on site, the accuracy of LIDAR-based ecosystem service indicators can be rigorously validated. With this conceptual and technical approach high resolution ecosystem service assessments can be made with well established credibility. These would consolidate the concept of ecosystem services and support both scientific research and evidence-based environmental policy at local and - as data coverage is continually increasing - continental scale.

  19. Airborne Submillimeter Spectroscopy

    NASA Technical Reports Server (NTRS)

    Zmuidzinas, J.

    1998-01-01

    This is the final technical report for NASA-Ames grant NAG2-1068 to Caltech, entitled "Airborne Submillimeter Spectroscopy", which extended over the period May 1, 1996 through January 31, 1998. The grant was funded by the NASA airborne astronomy program, during a period of time after the Kuiper Airborne Observatory was no longer operational. Instead. this funding program was intended to help develop instrument concepts and technology for the upcoming SOFIA (Stratospheric Observatory for Infrared Astronomy) project. SOFIA, which is funded by NASA and is now being carried out by a consortium lead by USRA (Universities Space Research Association), will be a 747 aircraft carrying a 2.5 meter diameter telescope. The purpose of our grant was to fund the ongoing development of sensitive heterodyne receivers for the submillimeter band (500-1200 GHz), using sensitive superconducting (SIS) detectors. In 1997 July we submitted a proposal to USRA to construct a heterodyne instrument for SOFIA. Our proposal was successful [1], and we are now continuing our airborne astronomy effort with funding from USRA. A secondary purpose of the NAG2-1068 grant was to continue the anaIN'sis of astronomical data collected with an earlier instrument which was flown on the NASA Kuiper Airborne Observatory (KAO). The KAO instrument and the astronomical studies which were carried out with it were supported primarily under another grant, NAG2-744, which extended over October 1, 1991 through Januarv 31, 1997. For a complete description of the astronomical data and its anailysis, we refer the reader to the final technical report for NAG2-744, which was submitted to NASA on December 1. 1997. Here we report on the SIS detector development effort for SOFIA carried out under NAG2-1068. The main result of this effort has been the demonstration of SIS mixers using a new superconducting material niobium titanium nitride (NbTiN), which promises to deliver dramatic improvements in sensitivity in the 700

  20. High-sensitivity, high-speed continuous imaging system

    DOEpatents

    Watson, Scott A; Bender, III, Howard A

    2014-11-18

    A continuous imaging system for recording low levels of light typically extending over small distances with high-frame rates and with a large number of frames is described. Photodiode pixels disposed in an array having a chosen geometry, each pixel having a dedicated amplifier, analog-to-digital convertor, and memory, provide parallel operation of the system. When combined with a plurality of scintillators responsive to a selected source of radiation, in a scintillator array, the light from each scintillator being directed to a single corresponding photodiode in close proximity or lens-coupled thereto, embodiments of the present imaging system may provide images of x-ray, gamma ray, proton, and neutron sources with high efficiency.

  1. Determination of impact sensitivity of materials at high pressures

    NASA Technical Reports Server (NTRS)

    Davis, L.; Pippen, D.; Stradling, J.; Whitaker, D.

    1972-01-01

    Compact device is used to determine impact sensitivity of material in static, high pressure, gaseous environment. It can also be instrumented to monitor and record pressure, temperature, and striker impact force. Device is used in conjunction with commercially available liquid oxygen impact tester which provides impact energy.

  2. Microelectromechanical Resonant Accelerometer Designed with a High Sensitivity.

    PubMed

    Zhang, Jing; Su, Yan; Shi, Qin; Qiu, An-Ping

    2015-01-01

    This paper describes the design and experimental evaluation of a silicon micro-machined resonant accelerometer (SMRA). This type of accelerometer works on the principle that a proof mass under acceleration applies force to two double-ended tuning fork (DETF) resonators, and the frequency output of two DETFs exhibits a differential shift. The dies of an SMRA are fabricated using silicon-on-insulator (SOI) processing and wafer-level vacuum packaging. This research aims to design a high-sensitivity SMRA because a high sensitivity allows for the acceleration signal to be easily demodulated by frequency counting techniques and decreases the noise level. This study applies the energy-consumed concept and the Nelder-Mead algorithm in the SMRA to address the design issues and further increase its sensitivity. Using this novel method, the sensitivity of the SMRA has been increased by 66.1%, which attributes to both the re-designed DETF and the reduced energy loss on the micro-lever. The results of both the closed-form and finite-element analyses are described and are in agreement with one another. A resonant frequency of approximately 22 kHz, a frequency sensitivity of over 250 Hz per g, a one-hour bias stability of 55 μg, a bias repeatability (1σ) of 48 μg and the bias-instability of 4.8 μg have been achieved. PMID:26633425

  3. Microelectromechanical Resonant Accelerometer Designed with a High Sensitivity

    PubMed Central

    Zhang, Jing; Su, Yan; Shi, Qin; Qiu, An-Ping

    2015-01-01

    This paper describes the design and experimental evaluation of a silicon micro-machined resonant accelerometer (SMRA). This type of accelerometer works on the principle that a proof mass under acceleration applies force to two double-ended tuning fork (DETF) resonators, and the frequency output of two DETFs exhibits a differential shift. The dies of an SMRA are fabricated using silicon-on-insulator (SOI) processing and wafer-level vacuum packaging. This research aims to design a high-sensitivity SMRA because a high sensitivity allows for the acceleration signal to be easily demodulated by frequency counting techniques and decreases the noise level. This study applies the energy-consumed concept and the Nelder-Mead algorithm in the SMRA to address the design issues and further increase its sensitivity. Using this novel method, the sensitivity of the SMRA has been increased by 66.1%, which attributes to both the re-designed DETF and the reduced energy loss on the micro-lever. The results of both the closed-form and finite-element analyses are described and are in agreement with one another. A resonant frequency of approximately 22 kHz, a frequency sensitivity of over 250 Hz per g, a one-hour bias stability of 55 μg, a bias repeatability (1σ) of 48 μg and the bias-instability of 4.8 μg have been achieved. PMID:26633425

  4. Quantifying erosion and deposition patterns using airborne LiDAR following the 2012 High Park Fire and 2013 Colorado Flood

    NASA Astrophysics Data System (ADS)

    Brogan, D. J.; Nelson, P. A.; MacDonald, L. H.

    2015-12-01

    Quantifying and predicting geomorphic change over large spatial scales is increasingly feasible and of growing interest as repeat high resolution topography becomes available. We began detailed field studies of channel geomorphic change using RTK-GPS in two 15 km2 watersheds following the 2012 High Park Fire; the watersheds were then subjected to a several-hundred year flood in September 2013. During this time a series of airborne LiDAR datasets were collected, and the objectives of this study were to: 1) determine and compare the spatial variability in channel and valley erosion and deposition over time from the LiDAR; and 2) determine if the observed changes can be predicted from channel and valley bottom characteristics. Data quality issues in the initial LiDAR required us to rotate and translate flight lines in order to co-register ground-classified point clouds between successive datasets; uncertainty was then estimated using our RTK-GPS field measurements. Topographic changes were calculated using the Multiscale Model to Model Cloud Comparison (M3C2) algorithm. Results indicate that the 2013 flood mobilized much more sediment than was mobilized due to the fire alone; unfortunately the uncertainty in differencing is still frequently greater than the observed changes, especially within transfer reaches. Valley expansion and constriction are major controls on spatial patterns of erosion and deposition, suggesting that topographic metrics such as longitudinal distributions of channel slope and valley confinement may provide quasi-physically based estimates of sediment deposition and delivery potential.

  5. Airborne infrared mineral mapping survey of Marysvale, Utah

    NASA Technical Reports Server (NTRS)

    Collins, W.; Chang, S. H.

    1982-01-01

    Infrared spectroradiometer survey results from flights over the Marysvale, Utah district show that hydrothermal alteration mineralogy can be mapped using very rapid and effective airborne techniques. The system detects alteration mineral absorption band intensities in the infrared spectral region with high sensitivity. The higher resolution spectral features and high spectral differences characteristic of the various clay and carbonate minerals are also readily identified by the instrument allowing the mineralogy to be mapped as well as the mineralization intensity.

  6. A survey of airborne radar systems for deployment on a High Altitude Powered Platform (HAPP)

    NASA Technical Reports Server (NTRS)

    Choudhury, B. J.; Leung, K. C.

    1979-01-01

    A survey was conducted to find out the system characteristics of commercially available and unclassified military radars suitable for deployment on a stationary platform. A total of ten domestic and eight foreign manufacturers of the radar systems were identified. Questionnaires were sent to manufacturers requesting information concerning the system characteristics: frequency, power used, weight, volume, power radiated, antenna pattern, resolution, display capabilities, pulse repetition frequency, and sensitivity. A literature search was also made to gather the system characteristics information. Results of the survey are documented and comparisons are made among available radar systems.

  7. NK sensitivity of neuroblastoma cells determined by a highly sensitive coupled luminescent method

    SciTech Connect

    Ogbomo, Henry; Hahn, Anke; Geiler, Janina; Michaelis, Martin; Doerr, Hans Wilhelm; Cinatl, Jindrich . E-mail: Cinatl@em.uni-frankfurt.de

    2006-01-06

    The measurement of natural killer (NK) cells toxicity against tumor or virus-infected cells especially in cases with small blood samples requires highly sensitive methods. Here, a coupled luminescent method (CLM) based on glyceraldehyde-3-phosphate dehydrogenase release from injured target cells was used to evaluate the cytotoxicity of interleukin-2 activated NK cells against neuroblastoma cell lines. In contrast to most other methods, CLM does not require the pretreatment of target cells with labeling substances which could be toxic or radioactive. The effective killing of tumor cells was achieved by low effector/target ratios ranging from 0.5:1 to 4:1. CLM provides highly sensitive, safe, and fast procedure for measurement of NK cell activity with small blood samples such as those obtained from pediatric patients.

  8. Porous silicon ring resonator for compact, high sensitivity biosensing applications

    SciTech Connect

    Rodriguez, Gilberto A.; Hu, Shuren; Weiss, Sharon M.

    2015-01-01

    A ring resonator is patterned on a porous silicon slab waveguide to produce a compact, high quality factor biosensor with a large internal surface area available for enhanced recognition of biological and chemical molecules. The porous nature of the ring resonator allows molecules to directly interact with the guided mode. Quality factors near 10,000 were measured for porous silicon ring resonators with a radius of 25 μm. A bulk detection sensitivity of 380 nm/RIU was measured upon exposure to salt water solutions. Specific detection of nucleic acid molecules was demonstrated with a surface detection sensitivity of 4 pm/nM.

  9. Highly mass-sensitive thin film plate acoustic resonators (FPAR).

    PubMed

    Arapan, Lilia; Alexieva, Gergana; Avramov, Ivan D; Radeva, Ekaterina; Strashilov, Vesseline; Katardjiev, Ilia; Yantchev, Ventsislav

    2011-01-01

    The mass sensitivity of thin aluminum nitride (AlN) film S0 Lamb wave resonators is theoretically and experimentally studied. Theoretical predictions based on modal and finite elements method analysis are experimentally verified. Here, two-port 888 MHz synchronous FPARs are micromachined and subsequently coated with hexamethyl-disiloxane(HMDSO)-plasma-polymerized thin films of various thicknesses. Systematic data on frequency shift and insertion loss versus film thickness are presented. FPARs demonstrate high mass-loading sensitivity as well as good tolerance towards the HMDSO viscous losses. Initial measurements in gas phase environment are further presented. PMID:22163994

  10. High sensitivity of positron annihilation to thermal oxidation of polyethylene

    NASA Astrophysics Data System (ADS)

    Ito, Kenji; Kobayashi, Yoshinori; Nanasawa, Atsushi

    2003-01-01

    We demonstrate the high sensitivity of positron annihilation to compositional changes related to the thermal degradation of polyethylene (PE). Positron annihilation γ-ray and lifetime measurements were conducted for PE films with and without antioxidant (1000-ppm Ciba® IRGANOX® 1076), subjected to heat treatment at 100 °C for different periods, to a maximum of 30 days. For the film without antioxidant, the positron Doppler parameter (S) and ortho-positronium formation probability (Io-Ps) appreciably decreased with increased heat treatment times, whereas they barely changed for the film with antioxidant. This, together with the Fourier transform infrared measurements, demonstrated that the variations of S and Io-Ps are caused by the thermal oxidation of PE. The S parameter was found to be sensitive to the early stage of degradation, where the carbonyl concentration is inferred to be lower than 100 ppm. The high sensitivity results from the large positron mobility in PE and from the high positron affinity of oxygen-containing polar groups. This work provides the basis for an application of positron annihilation to sensitive detection of the initial degradation of PE and other nonpolar polymers.

  11. Estimation of Evapotraspiration of Tamarisk using Energy Balance Models with High Resolution Airborne Imagery and LIDAR Data

    NASA Astrophysics Data System (ADS)

    Geli, H. M.; Taghvaeian, S.; Neale, C. M.; Pack, R.; Watts, D. R.; Osterberg, J.

    2010-12-01

    The wide uncontrolled spread of the invasive species of Tamarisk (Salt Cedar) in the riparian areas of the southwest of the United States has become a source of concern to the water resource management community. This tree which was imported for ornamental purposes and to control bank erosion during the 1800’s later became problematic and unwanted due to its biophysical properties: Its vigorous growth out-competes native species for moisture, lowering water tables, increasing the soil salinity and hence becomes the dominant riparian vegetation especially over arid to semi-arid floodplain environments. Most importantly they consume large amounts of water leading to reduction of river flows and lowering the groundwater table. We implemented this study in an effort to provide reliable estimates of the amount of water consumed or “lost” by such species through evapotranspiration (ET) as well as to a better understand of the related land surface and near atmosphere interactions. The recent advances in remote sensing techniques and the related data quality made it possible to provide spatio-temporal estimates of ET at a considerably higher resolution and reliable accuracy over a wide range of surface heterogeneity. We tested two different soil-vegetation atmosphere transfer models (SVAT) that are based on thermal remote sensing namely: the two source model (TSM) of Norman et al. (1995) with its recent modifications and the Surface Energy balance algorithm (SEBAL) of Bastiaanssen et al. (1998) to estimate the different surface energy balance components and the evapotranspiration (ET) spatially. We used high resolution (1.0 meter pixel size) shortwave reflectance and longwave thermal airborne imagery acquired by the research aircraft at the Remote Sensing Services Lab at Utah State University (USU) and land use map classified from these images as well as a detailed vegetation height image acquired by the LASSI Lidar also developed at USU. We also compared estimates

  12. A novel high-sensitivity FBG pressure sensor

    NASA Astrophysics Data System (ADS)

    Yao, Zhenhua; Fu, Tao; Leng, Jinsong

    2007-07-01

    A novel pressure sensor based on FBG is designed in this paper. Not only in normal environment, also does it accurately work in water and petrol where other conventional sensors can not work normally. In this paper, the principle of the novel sensor is introduced, and two experiments are further performed: One is keeping the sensor flatly in the gastight silo whose pressure is supplied by an air compressing engine, and the other one is keeping the sensor in liquid. The analysis of the result data demonstrates that the sensor possesses high sensitivity, high linearity, high precision and repeatability. Its experimental linearity and sensitivity approach 0.99858 and 5.35×10 -3MPa -1, respectively. It is also discussed using the sensor to measure the volume in tank.

  13. Integrated compact optical current sensors with high sensitivity

    NASA Astrophysics Data System (ADS)

    Huang, Duanni; Pintus, Paolo; Srinivasan, Sudharsanan; Bowers, John E.

    2016-02-01

    We demonstrate a Sagnac based fiber optic current sensor using only 10cm of terbium doped fiber with a high Verdet constant of 15.5 rad/Tm at a wavelength of 1300nm. Measurements of the fiber inside a solenoid show over 40dB of open loop dynamic range as well as a minimum detectable current of 0.1mA. In order to decrease size while increasing sensitivity even further, we consider integrated magneto-optic waveguides as the sensing element. Using silicon waveguides alongside magneto-optic material such as cerium doped yttrium iron garnet (Ce:YiG), we model the Verdet constant to be as high as 10,000 rad/Tm. This improvement by three orders of magnitude shows potential for magnetooptic waveguides to be used in ultra-high sensitivity optical magnetometers and current sensors. Finally, we propose a fully integrated optical current sensor using heterogeneous integration for silicon photonics.

  14. High-sensitivity linear piezoresistive transduction for nanomechanical beam resonators.

    PubMed

    Sansa, Marc; Fernández-Regúlez, Marta; Llobet, Jordi; San Paulo, Álvaro; Pérez-Murano, Francesc

    2014-01-01

    Highly sensitive conversion of motion into readable electrical signals is a crucial and challenging issue for nanomechanical resonators. Efficient transduction is particularly difficult to realize in devices of low dimensionality, such as beam resonators based on carbon nanotubes or silicon nanowires, where mechanical vibrations combine very high frequencies with miniscule amplitudes. Here we describe an enhanced piezoresistive transduction mechanism based on the asymmetry of the beam shape at rest. We show that this mechanism enables highly sensitive linear detection of the vibration of low-resistivity silicon beams without the need of exceptionally large piezoresistive coefficients. The general application of this effect is demonstrated by detecting multiple-order modes of silicon nanowire resonators made by either top-down or bottom-up fabrication methods. These results reveal a promising approach for practical applications of the simplest mechanical resonators, facilitating its manufacturability by very large-scale integration technologies. PMID:25000256

  15. Sensitivity of HAWC to high-mass dark matter annihilations

    NASA Astrophysics Data System (ADS)

    Abeysekara, A. U.; Alfaro, R.; Alvarez, C.; Álvarez, J. D.; Arceo, R.; Arteaga-Velázquez, J. C.; Ayala Solares, H. A.; Barber, A. S.; Baughman, B. M.; Bautista-Elivar, N.; Becerra Gonzalez, J.; Belmont, E.; BenZvi, S. Y.; Berley, D.; Bonilla Rosales, M.; Braun, J.; Caballero-Lopez, R. A.; Caballero-Mora, K. S.; Carramiñana, A.; Castillo, M.; Cotti, U.; Cotzomi, J.; de la Fuente, E.; De León, C.; DeYoung, T.; Diaz Hernandez, R.; Diaz-Cruz, L.; Díaz-Vélez, J. C.; Dingus, B. L.; DuVernois, M. A.; Ellsworth, R. W.; Fiorino, D. W.; Fraija, N.; Galindo, A.; Garfias, F.; González, M. M.; Goodman, J. A.; Grabski, V.; Gussert, M.; Hampel-Arias, Z.; Harding, J. P.; Hui, C. M.; Hüntemeyer, P.; Imran, A.; Iriarte, A.; Karn, P.; Kieda, D.; Kunde, G. J.; Lara, A.; Lauer, R. J.; Lee, W. H.; Lennarz, D.; León Vargas, H.; Linares, E. C.; Linnemann, J. T.; Longo, M.; Luna-Garcia, R.; Marinelli, A.; Martinez, H.; Martinez, O.; Martínez-Castro, J.; Matthews, J. A. J.; McEnery, J.; Mendoza Torres, E.; Miranda-Romagnoli, P.; Moreno, E.; Mostafá, M.; Nellen, L.; Newbold, M.; Noriega-Papaqui, R.; Oceguera-Becerra, T.; Patricelli, B.; Pelayo, R.; Pérez-Pérez, E. G.; Pretz, J.; Rivière, C.; Rosa-González, D.; Ryan, J.; Salazar, H.; Salesa, F.; Sanchez, F. E.; Sandoval, A.; Schneider, M.; Silich, S.; Sinnis, G.; Smith, A. J.; Sparks Woodle, K.; Springer, R. W.; Taboada, I.; Toale, P. A.; Tollefson, K.; Torres, I.; Ukwatta, T. N.; Villaseñor, L.; Weisgarber, T.; Westerhoff, S.; Wisher, I. G.; Wood, J.; Yodh, G. B.; Younk, P. W.; Zaborov, D.; Zepeda, A.; Zhou, H.; Abazajian, K. N.; Milagro Collaboration

    2014-12-01

    The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in central Mexico at 19° North latitude and 4100 m above sea level, HAWC will observe gamma rays and cosmic rays with an array of water Cherenkov detectors. The full HAWC array is scheduled to be operational in Spring 2015. In this paper, we study the HAWC sensitivity to the gamma-ray signatures of high-mass (multi-TeV) dark matter annihilation. The HAWC observatory will be sensitive to diverse searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from nonluminous dark matter subhalos. Here we consider the HAWC sensitivity to a subset of these sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the Galactic center. We simulate the HAWC response to gamma rays from these sources in several well-motivated dark matter annihilation channels. If no gamma-ray excess is observed, we show the limits HAWC can place on the dark matter cross section from these sources. In particular, in the case of dark matter annihilation into gauge bosons, HAWC will be able to detect a narrow range of dark matter masses to cross sections below thermal. HAWC should also be sensitive to nonthermal cross sections for masses up to nearly 1000 TeV. The constraints placed by HAWC on the dark matter cross section from known sources should be competitive with current limits in the mass range where HAWC has similar sensitivity. HAWC can additionally explore higher dark matter masses than are currently constrained.

  16. High-sensitivity microfluidic calorimeters for biological and chemical applications

    PubMed Central

    Lee, Wonhee; Fon, Warren; Axelrod, Blake W.; Roukes, Michael L.

    2009-01-01

    High-sensitivity microfluidic calorimeters raise the prospect of achieving high-throughput biochemical measurements with minimal sample consumption. However, it has been challenging to realize microchip-based calorimeters possessing both high sensitivity and precise sample-manipulation capabilities. Here, we report chip-based microfluidic calorimeters capable of characterizing the heat of reaction of 3.5-nL samples with 4.2-nW resolution. Our approach, based on a combination of hard- and soft-polymer microfluidics, provides both exceptional thermal response and the physical strength necessary to construct high-sensitivity calorimeters that can be scaled to automated, highly multiplexed array architectures. Polydimethylsiloxane microfluidic valves and pumps are interfaced to parylene channels and reaction chambers to automate the injection of analyte at 1 nL and below. We attained excellent thermal resolution via on-chip vacuum encapsulation, which provides unprecedented thermal isolation of the minute microfluidic reaction chambers. We demonstrate performance of these calorimeters by resolving measurements of the heat of reaction of urea hydrolysis and the enthalpy of mixing of water with methanol. The device structure can be adapted easily to enable a wide variety of other standard calorimeter operations; one example, a flow calorimeter, is described. PMID:19706406

  17. Highly efficient photocathodes for dye-sensitized tandem solar cells.

    PubMed

    Nattestad, A; Mozer, A J; Fischer, M K R; Cheng, Y-B; Mishra, A; Bäuerle, P; Bach, U

    2010-01-01

    Thin-film dye-sensitized solar cells (DSCs) based on mesoporous semiconductor electrodes are low-cost alternatives to conventional silicon devices. High-efficiency DSCs typically operate as photoanodes (n-DSCs), where photocurrents result from dye-sensitized electron injection into n-type semiconductors. Dye-sensitized photocathodes (p-DSCs) operate in an inverse mode, where dye-excitation is followed by rapid electron transfer from a p-type semiconductor to the dye (dye-sensitized hole injection). Such p-DSCs and n-DSCs can be combined to construct tandem solar cells (pn-DSCs) with a theoretical efficiency limitation well beyond that of single-junction DSCs (ref. 4). Nevertheless, the efficiencies of such tandem pn-DSCs have so far been hampered by the poor performance of the available p-DSCs (refs 3, 5-15). Here we show for the first time that p-DSCs can convert absorbed photons to electrons with yields of up to 96%, resulting in a sevenfold increase in energy conversion efficiency compared with previously reported photocathodes. The donor-acceptor dyes, studied as photocathodic sensitizers, comprise a variable-length oligothiophene bridge, which provides control over the spatial separation of the photogenerated charge carriers. As a result, charge recombination is decelerated by several orders of magnitude and tandem pn-DSCs can be constructed that exceed the efficiency of their individual components. PMID:19946281

  18. Highly efficient photocathodes for dye-sensitized tandem solar cells

    NASA Astrophysics Data System (ADS)

    Nattestad, A.; Mozer, A. J.; Fischer, M. K. R.; Cheng, Y.-B.; Mishra, A.; Bäuerle, P.; Bach, U.

    2010-01-01

    Thin-film dye-sensitized solar cells (DSCs) based on mesoporous semiconductor electrodes are low-cost alternatives to conventional silicon devices. High-efficiency DSCs typically operate as photoanodes (n-DSCs), where photocurrents result from dye-sensitized electron injection into n-type semiconductors. Dye-sensitized photocathodes (p-DSCs) operate in an inverse mode, where dye-excitation is followed by rapid electron transfer from a p-type semiconductor to the dye (dye-sensitized hole injection). Such p-DSCs and n-DSCs can be combined to construct tandem solar cells (pn-DSCs) with a theoretical efficiency limitation well beyond that of single-junction DSCs (ref. 4). Nevertheless, the efficiencies of such tandem pn-DSCs have so far been hampered by the poor performance of the available p-DSCs (refs 3, 5-15). Here we show for the first time that p-DSCs can convert absorbed photons to electrons with yields of up to 96%, resulting in a sevenfold increase in energy conversion efficiency compared with previously reported photocathodes. The donor-acceptor dyes, studied as photocathodic sensitizers, comprise a variable-length oligothiophene bridge, which provides control over the spatial separation of the photogenerated charge carriers. As a result, charge recombination is decelerated by several orders of magnitude and tandem pn-DSCs can be constructed that exceed the efficiency of their individual components.

  19. Organometallic carboxylate resists for extreme ultraviolet with high sensitivity

    NASA Astrophysics Data System (ADS)

    Passarelli, James; Murphy, Michael; Re, Ryan Del; Sortland, Miriam; Hotalen, Jodi; Dousharm, Levi; Fallica, Roberto; Ekinci, Yasin; Neisser, Mark; Freedman, Daniel A.; Brainard, Robert L.

    2015-10-01

    We have developed organometallic carboxylate compounds [RnM)] capable of acting as negative-tone extreme ultraviolet (EUV) resists. The most sensitive of these resists contain antimony, three R-groups and two carboxylate groups, and carboxylate groups with polymerizable olefins (e.g., acrylate, methacrylate, or styrenecarboxylate). Evidence suggests that high sensitivity is achieved through the polymerization of olefins in the exposed region. We have performed a systematic sensitivity study of the molecules of the type RnM) where we have studied seven R groups, four main group metals (M), and three polymerizable carboxylate groups (O2CR‧). The sensitivity of these resists was evaluated using Emax or dose to maximum resist thickness after exposure and development. We found that the greatest predictor of sensitivity of the RnSb) resists is their level of polymerizable olefins. We mathematically define the polymerizable olefin loading (POL) as the ratio of the number of olefins versus the number of nonhydrogen atoms. Linear and log plots of Emax versus POL for a variety of molecules of the type R3Sb) lend insight into the behavior of these resists.

  20. Crocodylus niloticus (Crocodilia) is highly sensitive to water surface waves.

    PubMed

    Grap, Nadja J; Monzel, Anna S; Kohl, Tobias; Bleckmann, Horst

    2015-10-01

    Crocodiles show oriented responses to water surface wave stimuli but up to now behavioral thresholds are missing. This study determines the behavioral thresholds of crocodilians to water surface waves. Nile crocodiles (Crocodylus niloticus) were conditioned to respond to single-frequency water surface wave stimuli (duration 1150 ms, frequency 15, 30, 40, 60 and 80 Hz), produced by blowing air onto the water surface. Our study shows that C. niloticus is highly sensitive to capillary water surface waves. Threshold values decreased with increasing frequency and ranged between 10.3 μm (15 Hz) and 0.5 μm (80 Hz) peak-to-peak wave amplitude. For the frequencies 15 Hz and 30 Hz the sensitivity of one spectacled caiman (Caiman crocodilus) to water surface waves was also tested. Threshold values were 12.8 μm (15 Hz) down to 1.76 μm (30 Hz), i.e. close to the threshold values of C. niloticus. The surface wave sensitivity of crocodiles is similar to the surface wave sensitivity of semi-aquatic insects and fishing spiders but does not match the sensitivity of surface-feeding fishes which is higher by one to two orders of magnitude. PMID:26153334

  1. [Design of airborne dual channel ultraviolet-visible imaging spectrometer with large field of view, wide spectrum, and high resolution].

    PubMed

    Hao, Ai-Hua; Hu, Bing-Liang; Bai, Jia-Guang; Li, Li-Bo; Yu, Tao; Li, Si-Yuan

    2013-12-01

    The ultraviolet-visible (UV-Vis 200-500 nm) imaging spectrometer is an important part of space remote sensing. Based on special requirements and practical application of the airborne UV-VIS spectrometer, a kind of scanning imaging spectrometer using area array CCD is proposed, which can meet the application requirements of large field of view, wide spectrum and high resolution. It overcomes low spatial resolution of traditional line array CCD scanning imaging spectrometer, and limited field of view of the pushbroom imaging spectrometer. In addition, dual channel was designed to reduce stray light. 400-500 nm band includes two order spectrum for 200-250 nm band, and variation of radiance from earth between the shorter wavelength (<290 nm) and the longer wavelength (>310 nm) is above three orders of magnitude. In the structure design of the system, the imaging spectrometer is composed of a two-mirror concentric telescope and two Czerny-Turner plane grating imaging spectrometers. The whole system doesn't use any additional optical elements in addition to spherical mirrors. The whole system has the advantage of simple structure, excellent performance, and very good feasibility. The modulation transfer function value of full spectrum and full field of view is above 0.6. PMID:24611417

  2. Characterizing Geology and Mineralization at High Latitudes in Alaska Using Airborne and Field-Based Imaging Spectrometer Data

    NASA Astrophysics Data System (ADS)

    Hoefen, T. M.; Kokaly, R. F.; Graham, G. E.; Kelley, K. D.; Buchhorn, M.; Johnson, M. R.; Hubbard, B. E.; Goldfarb, R. J.; Prakash, A.

    2015-12-01

    Passive optical remote sensing of high latitude regions faces many challenges including a short acquisition season and poor illumination. Identification of surface minerals can be complicated by steep terrain and vegetation cover. In July 2014, the HyMap* imaging spectrometer was flown over two study areas in Alaska. Contemporaneously, field spectra and samples of geologic units were collected, including altered and unaltered parts of intrusions hosting mid-Cretaceous porphyry copper deposits at Orange Hill and Bond Creek in the eastern Alaska Range. The HyMap radiance data were converted to surface reflectance using a radiative transfer correction program and reflectance spectra of calibration sites. Reflectance data were analyzed with the Material Identification and Characterization Algorithm (MICA), a module of USGS PRISM (Processing Routines in IDL for Spectroscopic Measurements; speclab.cr.usgs.gov). Large areas of abundant epidote/chlorite, muscovite/illite, calcite, kaolinite, montmorillonite, and (or) pyrophyllite were mapped, which are minerals typically formed during alteration of host rocks surrounding porphyry copper deposits. A map showing the wavelength position of the muscovite/illite absorption feature was made. Shifts in wavelength position have been related to the aluminum composition of micas and areas of high metal concentrations in past studies. In July 2015, rock and spectral sampling was continued in areas with surface exposures of copper- and molybdenum-bearing sulfides. Also, high-spatial resolution (~6 cm pixel size) imaging spectrometer data were collected at the Orange Hill deposit using the University of Alaska, Fairbanks (UAF) HySpex imaging spectrometer (www.hyperspectral.alaska.edu). Laboratory, field, and airborne spectra are being examined to define indicators of mineralization. The study results will be used to assess the effectiveness of spectroscopic remote sensing for geologic mapping and exploration targeting in Alaska and

  3. Real-time Data Processing and Visualization for the Airborne Scanning High-resolution Interferometer Sounder (S-HIS)

    NASA Astrophysics Data System (ADS)

    Taylor, J. K.; Revercomb, H. E.; Hoese, D.; Garcia, R. K.; Smith, W. L.; Weisz, E.; Tobin, D. C.; Best, F. A.; Knuteson, R. O.; Sullivan, D. V.; Barnes, C. M.; Van Gilst, D. P.

    2015-12-01

    The Hurricane and Severe Storm Sentinel (HS3) is a five-year NASA mission targeted to enhance the understanding of the formation and evolution of hurricanes in the Atlantic basin. Measurements were made from two NASA Global Hawk Unmanned Aircraft Systems (UAS) during the 2012 through 2014 hurricane seasons, with flights conducted from the NASA Wallops Flight Facility. The Global Hawk aircraft are capable of high altitude flights with durations of up to 30 hours, which allow extensive observations over distant storms, not typically possible with manned aircraft. The two NASA Global Hawks were equipped with instrument suites to study the storm environment, and inner core structure and processes, respectively. The Scanning High-resolution Interferometer Sounder (S-HIS), designed and built by the University of Wisconsin (UW) Space Science and Engineering Center (SSEC), measures emitted thermal radiation at high spectral resolution between 3.3 and 18 microns. The radiance measurements are used to obtain temperature and water vapor profiles of the Earth's atmosphere. The S-HIS spatial resolution is 2 km at nadir, across a 40 km ground swath from a nominal altitude of 20 kilometers. Since 1998, the S-HIS has participated in 33 field campaigns and has proven to be extremely dependable, effective, and highly accurate. It has flown on the NASA ER-2, DC-8, Proteus, WB-57, and Global Hawk airborne platforms. The UW S-HIS infrared sounder instrument is equipped with a real-time ground data processing system capable of delivering atmospheric profiles, radiance data, and engineering status to mission support scientists - all within less than one minute from the time of observation. This ground data processing system was assembled by a small team using existing software and proven practical techniques similar to a satellite ground system architecture. This summary outlines the design overview for the system and illustrates the data path, content, and outcomes.

  4. Airborne Raman lidar

    NASA Astrophysics Data System (ADS)

    Heaps, Wm. S.; Burris, J.

    1996-12-01

    We designed and tested an airborne lidar system using Raman scattering to make simultaneous measurements of methane, water vapor, and temperature in a series of flights on a NASA-operated C-130 aircraft. We present the results for methane detection, which show that the instrument has the requisite sensitivity to atmospheric trace gases. Ultimately these measurements can be used to examine the transport of chemically processed air from within the polar vortex to mid-latitudinal regions and the exchange of stratospheric air between tropical and mid-latitudinal regions.

  5. High-sensitivity three-mode optomechanical transducer

    SciTech Connect

    Zhao, C.; Fang, Q.; Susmithan, S.; Miao, H.; Ju, L.; Fan, Y.; Blair, D.; Hosken, D. J.; Munch, J.; Veitch, P. J.; Slagmolen, B. J. J.

    2011-12-15

    Three-mode optomechanical interactions have been predicted to allow the creation of very high sensitivity transducers in which very strong optical self-cooling and strong optomechanical quantum entanglement are predicted. Strong coupling is achieved by engineering a transducer in which both the pump laser and a single signal sideband frequency are resonantly enhanced. Here we demonstrate that very high sensitivity can be achieved in a very simple system consisting of a Fabry-Perot cavity with CO{sub 2} laser thermal tuning. We demonstrate a displacement sensitivity of {approx}1x10{sup -17} m/{radical}(Hz), which is sufficient to observe a thermally excited acoustic mode in a 5.6 kg sapphire mirror with a signal-to-noise ratio of more than 20 dB. It is shown that a measurement sensitivity of {approx}2x10{sup -20} m/{radical}(Hz) limited by the quantum shot noise is achievable with optimization of the cavity parameters.

  6. Anticipation of interoceptive threat in highly anxiety sensitive persons.

    PubMed

    Melzig, Christiane A; Michalowski, Jaroslaw M; Holtz, Katharina; Hamm, Alfons O

    2008-10-01

    Anticipatory anxiety plays a major role in the etiology of panic disorder. Although anticipatory anxiety elicited by expectation of interoceptive cues is specifically relevant for panic patients, it has rarely been studied. Using a population analogue in high fear of such interoceptive arousal sensations (highly anxiety sensitive persons) we evaluated a new experimental paradigm to assess anticipatory anxiety during anticipation of interoceptive (somatic sensations evoked by hyperventilation) and exteroceptive (electric shock) threat. Symptom reports, autonomic arousal, and defensive response mobilization (startle eyeblink response) were monitored during threat and matched safe conditions in 26 highly anxiety sensitive persons and 22 controls. The anticipation of exteroceptive threat led to a defensive and autonomic mobilization as indexed by a potentiation of the startle response and an increase in skin conductance level in both experimental groups. During interoceptive threat, however, only highly anxiety sensitive persons but not the controls exhibited a startle response potentiation as well as autonomic activation. The anticipation of a hyperventilation procedure thus seems a valid paradigm to investigate anticipatory anxiety elicited by interoceptive cues in the clinical context. PMID:18723161

  7. Airborne DIAL Ozone and Aerosol Trends Observed at High Latitudes Over North America from February to May 2000

    NASA Technical Reports Server (NTRS)

    Hair, Jonathan W.; Browell, Edward V.; Butler, Carolyn F.; Grant, William B.; DeYoung, Russell J.; Fenn, Marta A.; Brackett, Vince G.; Clayton, Marian B.; Brasseur, Lorraine

    2002-01-01

    Ozone (O3) and aerosol scattering ratio profiles were obtained from airborne lidar measurements on thirty-eight aircraft flights over seven aircraft deployments covering the latitudes of 40 deg.-85 deg.N between 4 February and 23 May 2000 as part of the TOPSE (Tropospheric Ozone Production about the Spring Equinox) field experiment. The remote and in situ O3 measurements were used together to produce a vertically-continuous O3 profile from near the surface to above the tropopause. Ozone, aerosol, and potential vorticity (PV) distributions were used together to identify the presence of pollution plumes and stratospheric intrusions. The number of observed pollution plumes was found to increase into the spring along with a significant increase in aerosol loading. Ozone was found to increase in the middle free troposphere (4-6 km) at high latitudes (60 deg.-85 deg. N) by an average of 4.3 ppbv/mo from about 55 ppbv in early February to over 72 ppbv in mid-May. The average aerosol scattering ratios in the same region increased at an average rate of 0.37/mo from about 0.35 to over 1.7. Ozone and aerosol scattering were highly correlated over entire field experiment. Based on the above results and the observed aircraft in-situ measurements, it was estimated that stratospherically-derived O3 accounted for less than 20% of the observed increase in mid tropospheric O3 at high latitudes. The primary cause of the observed O3 increase was found to be the photochemical production of O3 in pollution plumes.

  8. Mapping ET at high resolution in an advective semi-arid environment with airborne multispectral imagery

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Periodic and accurate estimates of spatially distributed evapotranspiration (ET) are essential for managing water in irrigated regions and in hydrologic modeling. In this study, METRIC (Mapping ET at high Resolution with Internalized Calibration), an energy balance algorithm originally developed for...

  9. Compact Tb doped fiber optic current sensor with high sensitivity.

    PubMed

    Huang, Duanni; Srinivasan, Sudharsanan; Bowers, John E

    2015-11-16

    A highly sensitive fiber optic current sensor using terbium doped fiber is presented. The Verdet constant of the terbium doped fiber at 1300nm is found to be 19.5μrad/A using both a polarimetric and interferometric type sensor. Measurements on a Sagnac-loop sensor using 10cm of terbium doped fiber placed inside a solenoid show over 40dB of open loop dynamic range as well as a minimum detectable current of 0.1mA. Extrapolations of our measurements show that in a practical setup with Tb fiber wrapped around a current carrying wire, the optimal configuration is a 0.5m piece of Tb fiber with a noise limit of 22mA/√Hz. This sensor is promising for current sensing applications that require high sensitivity and small size, weight, and power. PMID:26698480

  10. Quantum-Dot-Sensitized Solar Cell with Unprecedentedly High Photocurrent

    NASA Astrophysics Data System (ADS)

    Lee, Jin-Wook; Son, Dae-Yong; Ahn, Tae Kyu; Shin, Hee-Won; Kim, In Young; Hwang, Seong-Ju; Ko, Min Jae; Sul, Soohwan; Han, Hyouksoo; Park, Nam-Gyu

    2013-01-01

    The reported photocurrent density (JSC) of PbS quantum dot (QD)-sensitized solar cell was less than 19 mA/cm2 despite the capability to generate 38 mA/cm2, which results from inefficient electron injection and fast charge recombination. Here, we report on a PbS:Hg QD-sensitized solar cell with an unprecedentedly high JSC of 30 mA/cm2. By Hg2+ doping into PbS, JSC is almost doubled with improved stability. Femtosecond transient study confirms that the improved JSC is due to enhanced electron injection and suppressed charge recombination. EXAFS reveals that Pb-S bond is reinforced and structural disorder is reduced by interstitially incorporated Hg2+, which is responsible for the enhanced electron injection, suppressed recombination and stability. Thanks to the extremely high JSC, power conversion efficiency of 5.6% is demonstrated at one sun illumination.

  11. Development of High Sensitivity Nuclear Emulsion and Fine Grained Emulsion

    NASA Astrophysics Data System (ADS)

    Kawahara, H.; Asada, T.; Naka, T.; Naganawa, N.; Kuwabara, K.; Nakamura, M.

    2014-08-01

    Nuclear emulsion is a particle detector having high spacial resolution and angular resolution. It became useful for large statistics experiment thanks to the development of automatic scanning system. In 2010, a facility for emulsion production was introduced and R&D of nuclear emulsion began at Nagoya university. In this paper, we present results of development of the high sensitivity emulsion and fine grained emulsion for dark matter search experiment. Improvement of sensitivity is achieved by raising density of silver halide crystals and doping well-adjusted amount of chemicals. Production of fine grained emulsion was difficult because of unexpected crystal condensation. By mixing polyvinyl alcohol (PVA) to gelatin as a binder, we succeeded in making a stable fine grained emulsion.

  12. High-sensitivity acoustic sensors from nanofibre webs

    NASA Astrophysics Data System (ADS)

    Lang, Chenhong; Fang, Jian; Shao, Hao; Ding, Xin; Lin, Tong

    2016-03-01

    Considerable interest has been devoted to converting mechanical energy into electricity using polymer nanofibres. In particular, piezoelectric nanofibres produced by electrospinning have shown remarkable mechanical energy-to-electricity conversion ability. However, there is little data for the acoustic-to-electric conversion of electrospun nanofibres. Here we show that electrospun piezoelectric nanofibre webs have a strong acoustic-to-electric conversion ability. Using poly(vinylidene fluoride) as a model polymer and a sensor device that transfers sound directly to the nanofibre layer, we show that the sensor devices can detect low-frequency sound with a sensitivity as high as 266 mV Pa-1. They can precisely distinguish sound waves in low to middle frequency region. These features make them especially suitable for noise detection. Our nanofibre device has more than five times higher sensitivity than a commercial piezoelectric poly(vinylidene fluoride) film device. Electrospun piezoelectric nanofibres may be useful for developing high-performance acoustic sensors.

  13. Quantum-Dot-Sensitized Solar Cell with Unprecedentedly High Photocurrent

    PubMed Central

    Lee, Jin-Wook; Son, Dae-Yong; Ahn, Tae Kyu; Shin, Hee-Won; Kim, In Young; Hwang, Seong-Ju; Ko, Min Jae; Sul, Soohwan; Han, Hyouksoo; Park, Nam-Gyu

    2013-01-01

    The reported photocurrent density (JSC) of PbS quantum dot (QD)-sensitized solar cell was less than 19 mA/cm2 despite the capability to generate 38 mA/cm2, which results from inefficient electron injection and fast charge recombination. Here, we report on a PbS:Hg QD-sensitized solar cell with an unprecedentedly high JSC of 30 mA/cm2. By Hg2+ doping into PbS, JSC is almost doubled with improved stability. Femtosecond transient study confirms that the improved JSC is due to enhanced electron injection and suppressed charge recombination. EXAFS reveals that Pb-S bond is reinforced and structural disorder is reduced by interstitially incorporated Hg2+, which is responsible for the enhanced electron injection, suppressed recombination and stability. Thanks to the extremely high JSC, power conversion efficiency of 5.6% is demonstrated at one sun illumination. PMID:23308343

  14. A Novel High-Throughput Approach to Measure Hydroxyl Radicals Induced by Airborne Particulate Matter

    PubMed Central

    Son, Yeongkwon; Mishin, Vladimir; Welsh, William; Lu, Shou-En; Laskin, Jeffrey D.; Kipen, Howard; Meng, Qingyu

    2015-01-01

    Oxidative stress is one of the key mechanisms linking ambient particulate matter (PM) exposure with various adverse health effects. The oxidative potential of PM has been used to characterize the ability of PM induced oxidative stress. Hydroxyl radical (•OH) is the most destructive radical produced by PM. However, there is currently no high-throughput approach which can rapidly measure PM-induced •OH for a large number of samples with an automated system. This study evaluated four existing molecular probes (disodium terephthalate, 3′-p-(aminophenyl)fluorescein, coumarin-3-carboxylic acid, and sodium benzoate) for their applicability to measure •OH induced by PM in a high-throughput cell-free system using fluorescence techniques, based on both our experiments and on an assessment of the physicochemical properties of the probes reported in the literature. Disodium terephthalate (TPT) was the most applicable molecular probe to measure •OH induced by PM, due to its high solubility, high stability of the corresponding fluorescent product (i.e., 2-hydroxyterephthalic acid), high yield compared with the other molecular probes, and stable fluorescence intensity in a wide range of pH environments. TPT was applied in a high-throughput format to measure PM (NIST 1648a)-induced •OH, in phosphate buffered saline. The formed fluorescent product was measured at designated time points up to 2 h. The fluorescent product of TPT had a detection limit of 17.59 nM. The soluble fraction of PM contributed approximately 76.9% of the •OH induced by total PM, and the soluble metal ions of PM contributed 57.4% of the overall •OH formation. This study provides a promising cost-effective high-throughput method to measure •OH induced by PM on a routine basis. PMID:26516887

  15. Structural Glycomic Analyses at High Sensitivity: A Decade of Progress

    PubMed Central

    Alley, William R.; Novotny, Milos V.

    2014-01-01

    The field of glycomics has recently advanced in response to the urgent need for structural characterization and quantification of complex carbohydrates in biologically and medically important applications. The recent success of analytical glycobiology at high sensitivity reflects numerous advances in biomolecular mass spectrometry and its instrumentation, capillary and microchip separation techniques, and microchemical manipulations of carbohydrate reactivity. The multimethodological approach appears to be necessary to gain an in-depth understanding of very complex glycomes in different biological systems. PMID:23560930

  16. Sensitivity to Envelope Interaural Time Differences at High Modulation Rates

    PubMed Central

    Bleeck, Stefan; McAlpine, David

    2015-01-01

    Sensitivity to interaural time differences (ITDs) conveyed in the temporal fine structure of low-frequency tones and the modulated envelopes of high-frequency sounds are considered comparable, particularly for envelopes shaped to transmit similar fidelity of temporal information normally present for low-frequency sounds. Nevertheless, discrimination performance for envelope modulation rates above a few hundred Hertz is reported to be poor—to the point of discrimination thresholds being unattainable—compared with the much higher (>1,000 Hz) limit for low-frequency ITD sensitivity, suggesting the presence of a low-pass filter in the envelope domain. Further, performance for identical modulation rates appears to decline with increasing carrier frequency, supporting the view that the low-pass characteristics observed for envelope ITD processing is carrier-frequency dependent. Here, we assessed listeners’ sensitivity to ITDs conveyed in pure tones and in the modulated envelopes of high-frequency tones. ITD discrimination for the modulated high-frequency tones was measured as a function of both modulation rate and carrier frequency. Some well-trained listeners appear able to discriminate ITDs extremely well, even at modulation rates well beyond 500 Hz, for 4-kHz carriers. For one listener, thresholds were even obtained for a modulation rate of 800 Hz. The highest modulation rate for which thresholds could be obtained declined with increasing carrier frequency for all listeners. At 10 kHz, the highest modulation rate at which thresholds could be obtained was 600 Hz. The upper limit of sensitivity to ITDs conveyed in the envelope of high-frequency modulated sounds appears to be higher than previously considered. PMID:26721926

  17. Horizontal film balance having wide range and high sensitivity

    DOEpatents

    Abraham, B.M.; Miyano, K.; Ketterson, J.B.

    1981-03-05

    A thin-film, horizontal balance instrument is provided for measuring surface tension (surface energy) of thin films suspended on a liquid substrate. The balance includes a support bearing and an optical feedback arrangement for wide-range, high sensitivity measurements. The force on the instrument is balanced by an electromagnet, the current through the magnet providing a measure of the force applied to the instrument. A novel float construction is also disclosed.

  18. Horizontal film balance having wide range and high sensitivity

    DOEpatents

    Abraham, Bernard M.; Miyano, Kenjiro; Ketterson, John B.

    1983-01-01

    A thin-film, horizontal balance instrument is provided for measuring surface tension (surface energy) of thin films suspended on a liquid substrate. The balance includes a support bearing and an optical feedback arrangement for wide-range, high sensitivity measurements. The force on the instrument is balanced by an electromagnet, the current through the magnet providing a measure of the force applied to the instrument. A novel float construction is also disclosed.

  19. Horizontal film balance having wide range and high sensitivity

    DOEpatents

    Abraham, B.M.; Miyano, K.; Ketterson, J.B.

    1983-11-08

    A thin-film, horizontal balance instrument is provided for measuring surface tension (surface energy) of thin films suspended on a liquid substrate. The balance includes a support bearing and an optical feedback arrangement for wide-range, high sensitivity measurements. The force on the instrument is balanced by an electromagnet, the current through the magnet providing a measure of the force applied to the instrument. A novel float construction is also disclosed. 5 figs.

  20. High efficiency neutron sensitive amorphous silicon pixel detectors

    SciTech Connect

    Mireshghi, A.; Cho, G.; Drewery, J.S.; Hong, W.S.; Jing, T.; Lee, H.; Kaplan, S.N.; Perez-Mendez, V.

    1993-11-01

    A multi-layer a-Si:H based thermal neutron detector was designed, fabricated and simulated by Monte Carlo method. The detector consists of two PECVD deposited a-Si:H pin detectors interfaced with coated layers of Gd, as a thermal neutron converter. Simulation results indicate that a detector consisting of 2 Gd films with thicknesses of 2 and 4 {mu}m, sandwiched properly with two layers of sufficiently thick ({approximately}30{mu}m) amorphous silicon diodes, has the optimum parameters. The detectors have an intrinsic efficiency of about 42% at a threshold setting of 7000 electrons, with an expected average signal size of {approximately}12000 electrons which is well above the noise. This efficiency will be further increased to nearly 63%, if we use Gd with 50% enrichment in {sup 157}Gd. We can fabricate position sensitive detectors with spatial resolution of 300 {mu}m with gamma sensitivity of {approximately}1 {times} 10{sup {minus}5}. These detectors are highly radiation resistant and are good candidates for use in various application, where high efficiency, high resolution, gamma insensitive position sensitive neutron detectors are needed.

  1. Airborne transmission of H5N1 high pathogenicity avian influenza viruses during simulated home slaughter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most H5N1 human infections have occurred following exposure to H5N1 high pathogenicity avian influenza (HPAI) virus-infected poultry, especially when poultry are home slaughtered or slaughtered in live poultry markets. Previous studies have demonstrated that slaughter of clade 1 isolate A/Vietnam/1...

  2. ET mapping with METRIC algorithm using airborne high resolution multispectral remote sensing imagery

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Routine and accurate estimates of spatially distributed evapotranspiration (ET) are essential for managing water resources particularly in irrigated regions such as the U.S. Southern High Plains. For instance, ET maps would assist in the improvement of the Ogallala Aquifer ground water management. M...

  3. ET mapping with high-resolution airborne remote sensing data in an advective semiarid environment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate estimates of spatially distributed vegetation evapotranspiration (ET) are essential for managing water in irrigated regions and for hydrologic modeling. The METRIC**TM (Mapping ET at high Resolutions with Internal Calibration) energy balance algorithm was applied to derive ET from six very ...

  4. Comparison of Methods to Map and Measure River Terraces using High-Resolution Airborne LiDAR Data

    NASA Astrophysics Data System (ADS)

    Hopkins, A. J.; Snyder, N. P.

    2013-12-01

    Fluvial terraces are important recorders of land-use, climate, and tectonic history that form in both erosional and depositional landscapes and consist of a flat surface bounded by valley walls and a steep-sloping scarp adjacent to the river channel. Combining these defining characteristics with high-resolution digital elevation models (DEMs) derived from airborne light detection and ranging (lidar) surveys, several methods have been developed to identify and map terraces. The goals of this research are to compare some of these existing techniques and develop an objective approach to map terraces over entire watersheds using lidar DEMs. Additionally, we aim to quantify the thickness and volume of fill terrace deposits. Our preliminary application is to the Sheepscot River watershed, Maine, where strath and fill terraces are present and record Pleistocene deglaciation, Holocene eustatic forcing, and Anthropocene land-use change. We identify terraces along the longitudinal profile using an algorithm developed by Finnegan and Balco (2013), that computes the elevation frequency distribution at regularly spaced cross-sections normal to the channel. Next, we delineate terrace spatial extent using three separate methodologies: (1) image processing using Matlab, (2) feature classification algorithms developed by Wood (1996), and (3) image interpretation using manually placed points on known terraces to construct interpolated surfaces (Walter and Merritts, 2008). Lastly, we determine the thickness and volume of fill terrace sediments by subtracting an interpolated, adjacent water surface elevation from the defined terrace points. We compare our LiDAR-based results with field mapping, stratigraphic columns of terrace landforms, and ground penetrating radar over terrace surfaces. These findings suggest powerful new ways to rapidly analyze landscape history over large regions using high-resolution lidar DEMs, with less reliance on detailed and costly field data collection.

  5. Characteristics of Deep Tropical and Subtropical Convection from Nadir-Viewing High-Altitude Airborne Doppler Radar

    NASA Technical Reports Server (NTRS)

    Heymsfield, Gerald M.; Tian, Lin; Heymsfield, Andrew J.; Li, Lihua; Guimond, Stephen

    2010-01-01

    This paper presents observations of deep convection characteristics in the tropics and subtropics that have been classified into four categories: tropical cyclone, oceanic, land, and sea breeze. Vertical velocities in the convection were derived from Doppler radar measurements collected during several NASA field experiments from the nadir-viewing high-altitude ER-2 Doppler radar (EDOP). Emphasis is placed on the vertical structure of the convection from the surface to cloud top (sometimes reaching 18-km altitude). This unique look at convection is not possible from other approaches such as ground-based or lower-altitude airborne scanning radars. The vertical motions from the radar measurements are derived using new relationships between radar reflectivity and hydrometeor fall speed. Various convective properties, such as the peak updraft and downdraft velocities and their corresponding altitude, heights of reflectivity levels, and widths of reflectivity cores, are estimated. The most significant findings are the following: 1) strong updrafts that mostly exceed 15 m/s, with a few exceeding 30 m/s, are found in all the deep convection cases, whether over land or ocean; 2) peak updrafts were almost always above the 10-km level and, in the case of tropical cyclones, were closer to the 12-km level; and 3) land-based and sea-breeze convection had higher reflectivities and wider convective cores than oceanic and tropical cyclone convection. In addition, the high-resolution EDOP data were used to examine the connection between reflectivity and vertical velocity, for which only weak linear relationships were found. The results are discussed in terms of dynamical and microphysical implications for numerical models and future remote sensors.

  6. Analysis of Vegetation Within A Semi-Arid Urban Environment Using High Spatial Resolution Airborne Thermal Infrared Remote Sensing Data

    NASA Technical Reports Server (NTRS)

    Quattrochi, Dale A.; Ridd, Merrill K.

    1998-01-01

    High spatial resolution (5 m) remote sensing data obtained using the airborne Thermal Infrared Multispectral Scanner (TIMS) sensor for daytime and nighttime have been used to measure thermal energy responses for 2 broad classes and 10 subclasses of vegetation typical of the Salt Lake City, Utah urban landscape. Polygons representing discrete areas corresponding to the 10 subclasses of vegetation types have been delineated from the remote sensing data and are used for analysis of upwelling thermal energy for day, night, and the change in response between day and night or flux, as measured by the TIMS. These data have been used to produce three-dimensional graphs of energy responses in W/ sq m for day, night, and flux, for each urban vegetation land cover as measured by each of the six channels of the TIMS sensor. Analysis of these graphs provides a unique perspective for both viewing and understanding thermal responses, as recorded by the TIMS, for selected vegetation types common to Salt Lake City. A descriptive interpretation is given for each of the day, night, and flux graphs along with an analysis of what the patterns mean in reference to the thermal properties of the vegetation types surveyed in this study. From analyses of these graphs, it is apparent that thermal responses for vegetation can be highly varied as a function of the biophysical properties of the vegetation itself, as well as other factors. Moreover, it is also seen where vegetation, particularly trees, has a significant influence on damping or mitigating the amount of thermal radiation upwelling into the atmosphere across the Salt Lake City urban landscape. Published by Elsevier Science Ltd.

  7. A Residual Kriging method for the reconstruction of 3D high-resolution meteorological fields from airborne and surface observations

    NASA Astrophysics Data System (ADS)

    Laiti, Lavinia; Zardi, Dino; de Franceschi, Massimiliano; Rampanelli, Gabriele

    2013-04-01

    Manned light aircrafts and remotely piloted aircrafts represent very valuable and flexible measurement platforms for atmospheric research, as they are able to provide high temporal and spatial resolution observations of the atmosphere above the ground surface. In the present study the application of a geostatistical interpolation technique called Residual Kriging (RK) is proposed for the mapping of airborne measurements of scalar quantities over regularly spaced 3D grids. In RK the dominant (vertical) trend component underlying the original data is first extracted to filter out local anomalies, then the residual field is separately interpolated and finally added back to the trend; the determination of the interpolation weights relies on the estimate of the characteristic covariance function of the residuals, through the computation and modelling of their semivariogram function. RK implementation also allows for the inference of the characteristic spatial scales of variability of the target field and its isotropization, and for an estimate of the interpolation error. The adopted test-bed database consists in a series of flights of an instrumented motorglider exploring the atmosphere of two valleys near the city of Trento (in the southeastern Italian Alps), performed on fair-weather summer days. RK method is used to reconstruct fully 3D high-resolution fields of potential temperature and mixing ratio for specific vertical slices of the valley atmosphere, integrating also ground-based measurements from the nearest surface weather stations. From RK-interpolated meteorological fields, fine-scale features of the atmospheric boundary layer developing over the complex valley topography in connection with the occurrence of thermally-driven slope and valley winds, are detected. The performance of RK mapping is also tested against two other commonly adopted interpolation methods, i.e. the Inverse Distance Weighting and the Delaunay triangulation methods, comparing the results

  8. High-sensitivity active pixel sensor with variable threshold photodetector

    NASA Astrophysics Data System (ADS)

    Jo, Sung-Hyun; Bae, Myunghan; Choi, Byoung-Soo; Lyu, Hong-Kun; Shin, Jang-Kyoo

    2015-05-01

    A novel high-sensitivity active pixel sensor (APS) with a variable threshold photodetector has been presented and for the first time, a simple SPICE model for the variable threshold photodetector is presented. Its SPICE model is in good agreement with measurements and is more simpler than the conventional model. The proposed APS has a gate/body-tied PMOSFET-type photodetector with an overlapping control gate that makes it possible to control the sensitivity of the proposed APS. It is a hybrid device composed of a metal-oxide-semiconductor field-effect transistor (MOSFET), a lateral bipolar junction transistor (BJT) and a vertical BJT. Using sufficient overlapping control gate bias to operate the MOSFET in inversion mode, the variable threshold photodetector allows for increasing the photocurrent gain by 105 at low light intensities when the control gate bias is -3 V. Thus, the proposed APS with a variable threshold photodetector has better low-light-level sensitivity than the conventional APS operating mode, and it has a variable sensitivity which is determined by the control gate bias. The proposed sensor has been fabricated by using 0.35 μm 2-poly 4-metal standard complementary MOS (CMOS) process and its characteristics have been evaluated.

  9. Pulsed Discharge Helium Ionization Detector for Highly Sensitive Aquametry.

    PubMed

    Mowry, Curtis D; Pimentel, Adam S; Sparks, Elizabeth S; Moorman, Matthew W; Achyuthan, Komandoor E; Manginell, Ronald P

    2016-01-01

    Trace moisture quantitation is crucial in medical, civilian and military applications. Current aquametry technologies are limited by the sample volume, reactivity, or interferences, and/or instrument size, weight, power, cost, and complexity. We report for the first time on the use of a pulsed discharge helium ionization detector (PDHID-D2) (∼196 cm(3)) for the sensitive (limit of detection, 0.047 ng; 26 ppm), linear (r(2) >0.99), and rapid (< 2 min) quantitation of water using a small (0.2 - 5.0 μL) volume of liquid or gas. The relative humidity sensitivity was 0.22% (61.4 ppmv) with a limit of detection of less than 1 ng moisture with gaseous samples. The sensitivity was 10 to 100 to fold superior to competing technologies without the disadvantages inherent to these technologies. The PDHID-D2, due to its small footprint and low power requirement, has good size, weight, and power-portability (SWAPP) factors. The relatively low cost (∼$5000) and commercial availability of the PDHID-D2 makes our technique applicable to highly sensitive aquametry. PMID:26860562

  10. A novel high-sensitivity electrostatic biased electric field sensor

    NASA Astrophysics Data System (ADS)

    Huang, Jing'ao; Wu, Xiaoming; Wang, Xiaohong; Yan, Xiaojun; Lin, Liwei

    2015-09-01

    In this paper, an electric field sensor (EFS) with high sensitivity is proposed for low-frequency weak-strength ac electric field (E-field) measurements. The EFS is based on a piezoelectric cantilever biased by a strong electrostatic field. The electrostatic bias can enhance the electric field force of a weak ac E-field, thus the cantilever can oscillate in a weak ac E-field and the device sensitivity improves. Theoretical analyses have been established and suggest that a stronger strength of electrostatic field bias would produce a higher sensitivity improvement. In the experiment, a demonstrated sensor consisting of a polyvinylidene fluoride (PVDF) piezoelectric cantilever and a polytetrafluoroethylene (PTFE) electret was built and tested. Instead of extra voltage sources, the PTFE electret was charged to provide the electrostatic field, allowing the EFS a low energy consumption and a simple electric circuit design. The experiment results show good agreement with the simulation. The sensitivity of the cantilever E-field sensor reached 0.84 mV (kV/m)-1 when the surface potential of the electret was  -770 V.

  11. High sensitive volumetric imaging of renal microcirculation in vivo using ultrahigh sensitive optical microangiography

    NASA Astrophysics Data System (ADS)

    Zhi, Zhongwei; Jung, Yeongri; Jia, Yali; An, Lin; Wang, Ruikang K.

    2011-03-01

    We present a non-invasive, label-free imaging technique called Ultrahigh Sensitive Optical Microangiography (UHSOMAG) for high sensitive volumetric imaging of renal microcirculation. The UHS-OMAG imaging system is based on spectral domain optical coherence tomography (SD-OCT), which uses a 47000 A-line scan rate CCD camera to perform an imaging speed of 150 frames per second that takes only ~7 seconds to acquire a 3D image. The technique, capable of measuring slow blood flow down to 4 um/s, is sensitive enough to image capillary networks, such as peritubular capillaries and glomerulus within renal cortex. We show superior performance of UHS-OMAG in providing depthresolved volumetric images of rich renal microcirculation. We monitored the dynamics of renal microvasculature during renal ischemia and reperfusion. Obvious reduction of renal microvascular density due to renal ischemia was visualized and quantitatively analyzed. This technique can be helpful for the assessment of chronic kidney disease (CKD) which relates to abnormal microvasculature.

  12. Quantifying Fractional Ground Cover on the Climate Sensitive High Plains Using AVIRIS and Landsat TM Data

    NASA Technical Reports Server (NTRS)

    Warner, Amanda Susan

    2002-01-01

    The High Plains is an economically important and climatologically sensitive region of the United States and Canada. The High Plains contain 100,000 sq km of Holocene sand dunes and sand sheets that are currently stabilized by natural vegetation. Droughts and the larger threat of global warming are climate phenomena that could cause depletion of natural vegetation and make this region susceptible to sand dune reactivation. This thesis is part of a larger study that is assessing the effect of climate variability on the natural vegetation that covers the High Plains using Landsat 5 and Landsat 7 data. The question this thesis addresses is how can fractional vegetation cover be mapped with the Landsat instruments using linear spectral mixture analysis and to what accuracy. The method discussed in this thesis made use of a high spatial and spectral resolution sensor called AVIRIS (Airborne Visible and Infrared Imaging Spectrometer) and field measurements to test vegetation mapping in three Landsat 7 sub-scenes. Near-simultaneous AVIRIS images near Ft. Morgan, Colorado and near Logan, New Mexico were acquired on July 10, 1999 and September 30, 1999, respectively. The AVIRIS flights preceded Landsat 7 overpasses by approximately one hour. These data provided the opportunity to test spectral mixture algorithms with AVIRIS and to use these data to constrain the multispectral mixed pixels of Landsat 7. The comparisons of mixture analysis between the two instruments showed that AVIRIS endmembers can be used to unmix Landsat 7 data with good estimates of soil cover, and reasonable estimates of non-photosynthetic vegetation and green vegetation. Landsat 7 derived image endmembers correlate with AVIRIS fractions, but the error is relatively large and does not give a precise estimate of cover.

  13. Novel high sensitivity EUV photoresist for sub-7nm node

    NASA Astrophysics Data System (ADS)

    Nagai, Tomoki; Nakagawa, Hisashi; Naruoka, Takehiko; Tagawa, Seiichi; Oshima, Akihiro; Nagahara, Seiji; Shiraishi, Gosuke; Yoshihara, Kosuke; Terashita, Yuichi; Minekawa, Yukie; Buitrago, Elizabeth; Ekinci, Yasin; Yildirim, Oktay; Meeuwissen, Marieke; Hoefnagels, Rik; Rispens, Gijsbert; Verspaget, Coen; Maas, Raymond

    2016-03-01

    Extreme ultraviolet lithography (EUVL) has been recognized as the most promising candidate for the manufacture of semiconductor devices for the 7 nm node and beyond. A key point in the successful introduction of EUV lithography in high volume manufacture (HVM) is the effective EUV dose utilization while simultaneously realizing ultra-high resolution and low line edge roughness (LER). Here we show EUV resist sensitivity improvement with the use of a photosensitized chemically amplified resist PSCARTM system. The evaluation of this new chemically amplified resist (CAR) as performed using EUV interference lithography (EUV-IL) is described and the fundamentals are discussed.

  14. Resolving range ambiguities in high-repetition rate airborne lidar applications

    NASA Astrophysics Data System (ADS)

    Rieger, Peter; Ullrich, Andreas

    2011-11-01

    Correctly determining a measurement range in LIDAR instruments, based on time-of-flight measurements on laser pulses, requires the allocation of each received echo pulse to its causative emitted laser pulse. Without further precautions this definite allocation is only possible under specific conditions constraining the usability of range finders and laser scanners with very high measurement rates. Losing the unambiguity of ranges in high repetition systems is well known in RADAR and the term "multiple time around" (MTA) has been coined. However because of fundamental differences between scanning LIDAR and RADAR, with respect to MTA processing, new approaches for resolving range ambiguities in LIDAR are possible. In this paper we compare known and novel techniques for avoiding or even resolving range ambiguities without any further user interaction required. Such techniques may be based upon measures affecting hardware (e.g. spatial multiplexing or modulation of consecutive laser pulses), software (e.g. assumptions about the true measurement range based on a rough DTM) or both hard- and soft-ware in order to achieve a high probability of correctly resolved range ambiguities. Furthermore a comparison of different approaches is given, discussing their specific (dis-) advantages and their current status of implementation.

  15. [Air-borne disease].

    PubMed

    Lameiro Vilariño, Carmen; del Campo Pérez, Victor M; Alonso Bürger, Susana; Felpeto Nodar, Irene; Guimarey Pérez, Rosa; Pérez Alvarellos, Alberto

    2003-11-01

    Respiratory protection is a factor which worries nursing professionals who take care of patients susceptible of transmitting microorganisms through the air more as every day passes. This type of protection covers the use of surgical or hygienic masks against the transmission of infection by airborne drops to the use of highly effective masks or respirators against the transmission of airborne diseases such as tuberculosis or SARS, a recently discovered disease. The adequate choice of this protective device and its correct use are fundamental in order to have an effective protection for exposed personnel. The authors summarize the main protective respiratory devices used by health workers, their characteristics and degree of effectiveness, as well as the circumstances under which each device is indicated for use. PMID:14705591

  16. Very high resolution airborne imagery for characterising spatial and temporal thermal patterns of braided rivers

    NASA Astrophysics Data System (ADS)

    Wawrzyniak, V.; Piégay, H.; Allemand, P.; Grandjean, P.

    2011-12-01

    At the catchment scale water temperature is influenced by geographical factors, but at the reach scale superficial and groundwater hydrology and channel geometry strongly affect thermal patterns. During the last 30 years, studies have been pointed out the significance and complexity of water exchanges between the channel and the hyporheic and phreatic zones. These surface-subsurface water exchanges influence water temperature patterns. Braided rivers present particular thermal conditions with very high spatial water temperature variability. This high thermal variability is difficult to comprehend using only in situ measurements and so thermal infrared (TIR) remote sensing is particularly suited to assessing the thermal patterns associated with these rivers. The aims of this study are to evaluate temperature patterns of nine braided reaches at very high spatial resolution (~20 cm) and to link temperature and water-body types. We hypothesized that river type has an influence of the spatial patterns of water temperature and that the patterns change through the day. All reaches are located in France, in the Rhône catchment. The nine reaches were selected based on high aquatic habitat diversities and are located in three regional areas: the massif des Écrins, the Rhône valley, and south Alps. They are about 1 km long. We have three distinct temporal approaches. The first one is a multi-site approach which proposes one survey of each site during summers 2010 or 2011. Three reaches were selected for the second phase (a multi-annual analysis and were therefore imaged both in summers 2010 and 2011. The last phase is an intra-day survey of two reaches with several flights at different times of day. This presentation focuses on the last approach with two reaches of the Drôme and Drac Noir rivers. To observe the evolution of the thermal patterns of these two reaches through the day, four flights within a day were realized during summer 2011 for both sites. The Drôme reach

  17. A Compact Airborne High Spectral Resolution Lidar for Observations of Aerosol and Cloud Optical Properties

    NASA Technical Reports Server (NTRS)

    Hostetler, Chris A.; Hair, John W.; Cook, Anthony L.

    2002-01-01

    We are in the process of developing a nadir-viewing, aircraft-based high spectral resolution lidar (HSRL) at NASA Langley Research Center. The system is designed to measure backscatter and extinction of aerosols and tenuous clouds. The primary uses of the instrument will be to validate spaceborne aerosol and cloud observations, carry out regional process studies, and assess the predictions of chemical transport models. In this paper, we provide an overview of the instrument design and present the results of simulations showing the instrument's capability to accurately measure extinction and extinction-to-backscatter ratio.

  18. Approaches to a broad range of high performance PDT sensitizers

    NASA Astrophysics Data System (ADS)

    d'A. Rocha Gonsalves, António M.; Serra, Arménio C.; Pineiro, Marta; Botelho, M. Filomena

    2009-02-01

    Starting from expertise in the area of chemical synthesis, particularly in tetrapyrrolic macrocycles and an interest in modelling structures for particular objectives, we came to the point of aiming at modelling photochemical sensitizers designed for photodynamic therapy (PDT) purposes. Our endeavours were gratifying when it was proved that our synthetic methodologies allowed for the easy availability of properly halogenated porphyrins with high quantum yield singlet oxygen efficiency. Joining the presence of this heavy atom and other functionalities as substituents in selected positions of macrocyclic structures we were able to generate novel porphyrin structures whose photophysical and photochemical properties, singlet oxygen formation quantum yields, photobleaching and logP were measured. Cellular uptake measurements and cytotoxicity assays on WiDr adenocarcinoma and A375 tumor cell lines were carried out and some of our porphyrins demonstrated very high performance as PDT sensitizers comparatively to known compounds approved for clinical use and in the market. Further developments of our studies allowed for the generation of different and more efficient structures, easily made available by our own synthetic methodologies. Our studies in this area allowed us to reach a stage which we believe to correspond to a significant knowledge and capacity to synthesise a broad range of simple structures, whose selectivity and efficiency as PDT sensitizers can be modulated for different cellular and tissue specificities. Our most recent developments in this area will be presented in this communication.

  19. High-sensitivity strain visualization using electroluminescence technologies

    NASA Astrophysics Data System (ADS)

    Xu, Jian; Jo, Hongki

    2016-04-01

    Visualizing mechanical strain/stress changes is an emerging area in structural health monitoring. Several ways are available for strain change visualization through the color/brightness change of the materials subjected to the mechanical stresses, for example, using mechanoluminescence (ML) materials and mechanoresponsive polymers (MRP). However, these approaches were not effectively applicable for civil engineering system yet, due to insufficient sensitivity to low-level strain of typical civil structures and limitation in measuring both static and dynamic strain. In this study, design and validation for high-sensitivity strain visualization using electroluminescence technologies are presented. A high-sensitivity Wheatstone bridge, of which bridge balance is precisely controllable circuits, is used with a gain-adjustable amplifier. The monochrome electroluminescence (EL) technology is employed to convert both static and dynamic strain change into brightness/color change of the EL materials, through either brightness change mode (BCM) or color alternation mode (CAM). A prototype has been made and calibrated in lab, the linearity between strain and brightness change has been investigated.

  20. High-sensitive scanning laser magneto-optical imaging system

    SciTech Connect

    Murakami, Hironaru; Tonouchi, Masayoshi

    2010-01-15

    A high-sensitive scanning laser magneto-optical (MO) imaging system has been developed. The system is mainly composed of a laser source, galvano meters, and a high-sensitive differential optical-detector. Preliminary evaluation of system performance by using a Faraday indicator with a Faraday rotation coefficient of 3.47x10{sup -5} rad/{mu}m Oe shows a magnetic sensitivity of about 5 {mu}T, without any need for accumulation or averaging processing. Using the developed MO system we have succeeded in the fast and quantitative imaging of a rotationally symmetric magnetic field distribution around an YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) strip line applied with dc-biased current, and also succeeded in the detection of quantized fine signals corresponding to magnetic flux quantum generation in a superconducting loop of an YBCO Josephson vortex flow transistor. Thus, the developed system enables us not only to do fast imaging and local signal detection but also to directly evaluate both the strength and direction of a magnetic signal.

  1. High-sensitive scanning laser magneto-optical imaging system.

    PubMed

    Murakami, Hironaru; Tonouchi, Masayoshi

    2010-01-01

    A high-sensitive scanning laser magneto-optical (MO) imaging system has been developed. The system is mainly composed of a laser source, galvano meters, and a high-sensitive differential optical-detector. Preliminary evaluation of system performance by using a Faraday indicator with a Faraday rotation coefficient of 3.47 x 10(-5) rad/microm Oe shows a magnetic sensitivity of about 5 microT, without any need for accumulation or averaging processing. Using the developed MO system we have succeeded in the fast and quantitative imaging of a rotationally symmetric magnetic field distribution around an YBa(2)Cu(3)O(7-delta) (YBCO) strip line applied with dc-biased current, and also succeeded in the detection of quantized fine signals corresponding to magnetic flux quantum generation in a superconducting loop of an YBCO Josephson vortex flow transistor. Thus, the developed system enables us not only to do fast imaging and local signal detection but also to directly evaluate both the strength and direction of a magnetic signal. PMID:20113101

  2. An evaluation of an ultra-high-volume airborne particulate sampler, the LEAP.

    PubMed

    Tu, K W

    1984-06-01

    A modified ultra-high-volume liquid electrostatic aerosol precipitator sampler (LEAP) was calibrated with near monodisperse aerosols of water-soluble and insoluble materials in the size range of 0.02 to 4 microns diameter. The water-soluble materials were ammonium sulfate and ammonium hydrogen sulfate. The insoluble materials included carnauba wax, stearic acid, silver chloride and Y(THD)3. The particulate collection efficiency of the unit ranged from 40 to 98%, depending on particle size, sampling air flow and also on particle material. Tests with water-soluble aerosols showed higher collection efficiency than those with the insoluble aerosols by about 2 to 10%. A sharp decline in the collection efficiency for the particles smaller than 0.1 micron was observed. A comparison with the available manufacturer's data for the particle diameters of 0.1 to 3 microns suggests that the manufacturer overestimated the collection efficiency by 6 to 20% for an air flow of 10 m3/min. We consider the LEAP to be a useful ultra-high volume sampler, especially suited for low-level or short-term sampling. PMID:6741789

  3. Evaluation of an ultra-high-volume airborne particulate sampler, the LEAP

    SciTech Connect

    Tu, K.W.

    1984-06-01

    A modified ultra-high-volume liquid electrostatic aerosol precipitator sampler (LEAP) was calibrated with near monodisperse aerosols of water-soluble and insoluble materials in the size range of 0.02 to 4 ..mu..m diameter. The water-soluble materials were ammonium sulfate and ammonium hydrogen sulfate. The insoluble materials included carnauba wax, stearic acid, silver chloride and Y(THD)/sub 3/. The particulate collection efficiency of the unit ranged from 40 to 98%, depending on particle size, sampling air flow and also on particle material. Tests with water-soluble aerosols showed higher collection efficiency than those with the insoluble aerosols by about 2 to 10%. A sharp decline in the collection efficiency for the particles smaller than 0.1 ..mu..m was observed. A comparison with the available manufacturer's data for the particle diameters of 0.1 to 3 ..mu..m suggests that the manufacturer overestimated the collection efficiency by 6 to 20% for an air flow of 10 m/sup 3//min. The LEAP is considered to be a useful ultra-high volume sampler, especially suited for low-level or short-term sampling.

  4. New optical sensor systems for high-resolution satellite, airborne and terrestrial imaging systems

    NASA Astrophysics Data System (ADS)

    Eckardt, Andreas; Börner, Anko; Lehmann, Frank

    2007-10-01

    The department of Optical Information Systems (OS) at the Institute of Robotics and Mechatronics of the German Aerospace Center (DLR) has more than 25 years experience with high-resolution imaging technology. The technology changes in the development of detectors, as well as the significant change of the manufacturing accuracy in combination with the engineering research define the next generation of spaceborne sensor systems focusing on Earth observation and remote sensing. The combination of large TDI lines, intelligent synchronization control, fast-readable sensors and new focal-plane concepts open the door to new remote-sensing instruments. This class of instruments is feasible for high-resolution sensor systems regarding geometry and radiometry and their data products like 3D virtual reality. Systemic approaches are essential for such designs of complex sensor systems for dedicated tasks. The system theory of the instrument inside a simulated environment is the beginning of the optimization process for the optical, mechanical and electrical designs. Single modules and the entire system have to be calibrated and verified. Suitable procedures must be defined on component, module and system level for the assembly test and verification process. This kind of development strategy allows the hardware-in-the-loop design. The paper gives an overview about the current activities at DLR in the field of innovative sensor systems for photogrammetric and remote sensing purposes.

  5. Airborne reconnaissance in the civilian sector - Agricultural monitoring from high-altitude powered platforms

    NASA Technical Reports Server (NTRS)

    Youngblood, J. W.; Jackson, R. D.

    1983-01-01

    Design concepts and mission applications for unmanned high-altitude powered platforms (HAPPs) are discussed. A chemically powered HAPP (operating altitude 18-21 km, wingspan 26 m, payload 91 kg, endurance 2-3 days) would use current turboprop technology. A microwave-powered HAPP (operating altitude around 21 km, wingspan 57.9 m, payload 500 kg, endurance weeks or months) would circle within or perform boost-glide maneuvers around a microwave beam of density 1.1 kw/sq m. Of two solar-powered-HAPP designs presented, the more promising uses five vertical solar-panel-bearing fins, two of which can be made horizontal at night, (wingspan 57.8/98.3 m, payload 113 kg, endurance weeks or months). The operating altitude depends on the latitude and season: this HAPP design is shown to be capable of year-round 20-km-altitude flights over the San Joaquin Valley in California, where an agricultural-monitoring mission using Landsat-like remote sensors is proposed. Other applications may be better served by the characteristics of the other HAPPs. The primary advantage of HAPPs over satellites is found to be their ability to provide rapidly available high-resolution continuous or repetitive coverage of specific areas at relatively low cost.

  6. Highly sensitive Fourier transform spectroscopy with LED sources

    NASA Astrophysics Data System (ADS)

    Serdyukov, V. I.; Sinitsa, L. N.; Vasil'chenko, S. S.

    2013-08-01

    It is shown that the use of high luminance LED emitters as a light source for Fourier transform spectrometers permits to enhance their threshold sensitivity in the visible range by orders of magnitude. Using a 2.5 W Edixeon EDEI-1LS3 emitter in the range of 11,350-11,700 cm-1 as a light source for the spectrometer with a 60-cm multipass cell during a 24-h measurement time, we have achieved a signal-to-noise ratio of 4.5 × 104 which corresponds to the minimal detectable absorption coefficient of 1.2 × 10-8 cm-1. Such enhanced sensitivity spectrometer has been used to measure the transition frequencies of CO2 vibrational bands 00051-00001 and 01151-01101 in the range of 11,400-11,500 cm-1.

  7. Polymer-Particle Pressure-Sensitive Paint with High Photostability.

    PubMed

    Matsuda, Yu; Uchida, Kenta; Egami, Yasuhiro; Yamaguchi, Hiroki; Niimi, Tomohide

    2016-01-01

    We propose a novel fast-responding and paintable pressure-sensitive paint (PSP) based on polymer particles, i.e. polymer-particle (pp-)PSP. As a fast-responding PSP, polymer-ceramic (PC-)PSP is widely studied. Since PC-PSP generally consists of titanium (IV) oxide (TiO₂) particles, a large reduction in the luminescent intensity will occur due to the photocatalytic action of TiO₂. We propose the usage of polymer particles instead of TiO₂ particles to prevent the reduction in the luminescent intensity. Here, we fabricate pp-PSP based on the polystyrene particle with a diameter of 1 μm, and investigate the pressure- and temperature-sensitives, the response time, and the photostability. The performances of pp-PSP are compared with those of PC-PSP, indicating the high photostability with the other characteristics comparable to PC-PSP. PMID:27092511

  8. High-sensitivity permeation measurements on flexible OLED substrates

    NASA Astrophysics Data System (ADS)

    Paetzold, Ralph; Henseler, Debora; Heuser, Karsten; Cesari, Valentina; Sarfert, Wiebke; Wittmann, Georg; Winnacker, Albrecht

    2004-02-01

    We describe a novel method to measure permeation rates for oxidizing agents with very high sensitivity. The technique is based on monitoring the resistance of a degrading Ca sensor in situ, inside a climate chamber. A sensitivity limit below 10-6 g/m2 day is reported for accelerated measurement conditions of 38°C and 90% relative humidity. The benefits of the method are demonstrated for single- and double-sided barrier foils, and the temperature and humidity dependence of the transport through PET is analyzed in detail. The method is also applied to obtain permeation rates for a barrier-coated substrate after as well as during bending. Theoretical simulations are used to evaluate the influence of a defect-dominated transport mechanism on the experimental results and to model the time evolution of the concentration profile in a double-barrier stack. Implications for the development of barrier-enhanced substrates for flexible OLED applications are discussed.

  9. Polymer-Particle Pressure-Sensitive Paint with High Photostability

    PubMed Central

    Matsuda, Yu; Uchida, Kenta; Egami, Yasuhiro; Yamaguchi, Hiroki; Niimi, Tomohide

    2016-01-01

    We propose a novel fast-responding and paintable pressure-sensitive paint (PSP) based on polymer particles, i.e. polymer-particle (pp-)PSP. As a fast-responding PSP, polymer-ceramic (PC-)PSP is widely studied. Since PC-PSP generally consists of titanium (IV) oxide (TiO2) particles, a large reduction in the luminescent intensity will occur due to the photocatalytic action of TiO2. We propose the usage of polymer particles instead of TiO2 particles to prevent the reduction in the luminescent intensity. Here, we fabricate pp-PSP based on the polystyrene particle with a diameter of 1 μm, and investigate the pressure- and temperature-sensitives, the response time, and the photostability. The performances of pp-PSP are compared with those of PC-PSP, indicating the high photostability with the other characteristics comparable to PC-PSP. PMID:27092511

  10. Highly Sensitive Measurements of 222Rn Diffusion and Emanation

    SciTech Connect

    Zuzel, Grzegorz

    2005-09-08

    Highly sensitive techniques for determination of the 222Rn emanation from solids and diffusion through different membranes are presented. 222Rn and its daughters are measured via the alpha decays in special proportional counters at the absolute sensitivity of {approx}30 {mu}Bq. Radon diffusion can be measured at the level of {approx}10-13 cm2/s. Several samples were examined, e.g. stainless steel, teflon, various gaskets (emanation and diffusion measurements) and tanks. A combination of measurements of the 222Rn diffusion and emanation of thin nylon foils (used in the Borexino experiment) allowed the determination of 226Ra in the materials of interest at the level of {approx}10-12 g/g 238U-equivalent.

  11. Inter-flat airflow and airborne disease transmission in high-rise residential buildings.

    PubMed

    Niu, J; Tung, C W; Gao, N

    2012-02-01

    1. A virus-spread mechanism is related to inter-flat or interzonal airflow through open windows caused by buoyancy effects. 2. Both on-site measurements and numerical simulations quantify the amount of the exhaust air that exits the upper part of the window of a floor and re-enters the lower part of the open window of the immediately upper floor. 3. Ventilation air could contain up to 7% (in terms of mass fraction) of the exhaust air from the lower floor.4. In high-rise buildings, windows flush with the façade are a major route for the vertical spread of pathogen-containing aerosols, especially those<1 μm in diameter. PMID:22311361

  12. High Power and Frequency-Agile Optical Parametric Oscillators for Airborne DIAL Measurements of CH4 and H2O

    NASA Astrophysics Data System (ADS)

    Nehrir, A. R.; Shuman, T.; Chuang, T.; Hair, J. W.; Refaat, T. F.; Ismail, S.; Kooi, S. A.; Notari, A.

    2014-12-01

    Atmospheric methane (CH4) has the second largest radiative forcing of the long-lived greenhouse gasses (GHG) after carbon dioxide. However, methane's much shorter atmospheric lifetime and much stronger warming potential make its radiative forcing equivalent to that for CO2 over a 20-year time horizon which makes CH4 a particularly attractive target for mitigation strategies. Similar to CH4, water vapor (H2O) is the most dominant of the short-lived GHG in the atmosphere and plays a key role in many atmospheric processes. Atmospheric H2O concentrations span over four orders of magnitude from the planetary boundary layer where high impact weather initiates to lower levels in the upper troposphere and lower stratosphere (UTLS) where water vapor has significant and long term impacts on the Earth's radiation budget. NASA Langley has fostered the technology development with Fibertek, Inc. to develop frequency agile and high power (> 3 W) pulsed lasers using similar architectures in the 1645 nm and 935 nm spectral bands for DIAL measurements of CH4 and H2O, respectively. Both systems utilize high power 1 kHz pulse repetition frequency Nd:YAG lasers to generate high power laser emission at the desired wavelength via optical parametric oscillators (OPO). The CH4 OPO, currently in its final build stage in a SBIR Phase II program has demonstrated >2 W average power with injection seeding from a distributed feedback (DFB) laser during risk reduction experiments. The H2O OPO has demonstrated high power operation (>2 W) during the SBIR Phase I program while being injection seeded with a DFB laser, and is currently funded via an SBIR Phase II to build a robust system for future integration into an airborne water vapor DIAL system capable of profiling from the boundary layer up to the UTLS. Both systems have demonstrated operation with active OPO wavelength control to allow for optimization of the DIAL measurements for operation at different altitudes and geographic regions. An

  13. A CMOS In-Pixel CTIA High Sensitivity Fluorescence Imager

    PubMed Central

    Murari, Kartikeya; Etienne-Cummings, Ralph; Thakor, Nitish; Cauwenberghs, Gert

    2012-01-01

    Traditionally, charge coupled device (CCD) based image sensors have held sway over the field of biomedical imaging. Complementary metal oxide semiconductor (CMOS) based imagers so far lack sensitivity leading to poor low-light imaging. Certain applications including our work on animal-mountable systems for imaging in awake and unrestrained rodents require the high sensitivity and image quality of CCDs and the low power consumption, flexibility and compactness of CMOS imagers. We present a 132×124 high sensitivity imager array with a 20.1 μm pixel pitch fabricated in a standard 0.5 μ CMOS process. The chip incorporates n-well/p-sub photodiodes, capacitive transimpedance amplifier (CTIA) based in-pixel amplification, pixel scanners and delta differencing circuits. The 5-transistor all-nMOS pixel interfaces with peripheral pMOS transistors for column-parallel CTIA. At 70 fps, the array has a minimum detectable signal of 4 nW/cm2 at a wavelength of 450 nm while consuming 718 μA from a 3.3 V supply. Peak signal to noise ratio (SNR) was 44 dB at an incident intensity of 1 μW/cm2. Implementing 4×4 binning allowed the frame rate to be increased to 675 fps. Alternately, sensitivity could be increased to detect about 0.8 nW/cm2 while maintaining 70 fps. The chip was used to image single cell fluorescence at 28 fps with an average SNR of 32 dB. For comparison, a cooled CCD camera imaged the same cell at 20 fps with an average SNR of 33.2 dB under the same illumination while consuming over a watt. PMID:23136624

  14. A high sensitivity inductive sensor for blade tip clearance measurement

    NASA Astrophysics Data System (ADS)

    Du, Li; Zhu, Xiaoliang; Zhe, Jiang

    2014-06-01

    A multiplexed inductive sensor consisting of multiple mini-sized planar spiral coils for detecting multiple tip clearances of rotor blades is presented. The sensor measures the tip clearances by monitoring the inductance changes of planar spiral coils caused by the passage of the rotor blades. A resonance frequency division multiplexing technique and parallel LC resonance measurement were applied to the multiple sensor coils, making it feasible to measure multiple tip clearances using only one set of measurement electronics with high sensitivity and resolution. The results from tests conducted on a bench-top test rig have demonstrated that the sensor is capable of simultaneously measuring multiple tip clearances from 0 to 5 mm with a 10 μm resolution at a high rotary speed up to 80 000 RPM. With its high resolution, high sensitivity and capability of monitoring a large number of tip clearances simultaneously, this sensor can potentially be used for advanced active tip clearance control in turbine machinery.

  15. High Sensitivity MEMS Strain Sensor: Design and Simulation

    PubMed Central

    Mohammed, Ahmed A. S.; Moussa, Walied A.; Lou, Edmond

    2008-01-01

    In this article, we report on the new design of a miniaturized strain microsensor. The proposed sensor utilizes the piezoresistive properties of doped single crystal silicon. Employing the Micro Electro Mechanical Systems (MEMS) technology, high sensor sensitivities and resolutions have been achieved. The current sensor design employs different levels of signal amplifications. These amplifications include geometric, material and electronic levels. The sensor and the electronic circuits can be integrated on a single chip, and packaged as a small functional unit. The sensor converts input strain to resistance change, which can be transformed to bridge imbalance voltage. An analog output that demonstrates high sensitivity (0.03mV/με), high absolute resolution (1με) and low power consumption (100μA) with a maximum range of ±4000με has been reported. These performance characteristics have been achieved with high signal stability over a wide temperature range (±50°C), which introduces the proposed MEMS strain sensor as a strong candidate for wireless strain sensing applications under harsh environmental conditions. Moreover, this sensor has been designed, verified and can be easily modified to measure other values such as force, torque…etc. In this work, the sensor design is achieved using Finite Element Method (FEM) with the application of the piezoresistivity theory. This design process and the microfabrication process flow to prototype the design have been presented.

  16. 355-nm high spectral resolution airborne lidar LNG: system description and first results.

    PubMed

    Bruneau, D; Pelon, J; Blouzon, F; Spatazza, J; Genau, P; Buchholtz, G; Amarouche, N; Abchiche, A; Aouji, O

    2015-10-10

    A high spectral resolution (HSR) measurement capability in the ultraviolet has been added to the 3-wavelength-2-polarization-backscatter lidar LNG (lidar aerosols nouvelle génération) and tested during several flights. The system includes a Mach-Zehnder interferometer (MZI) as a spectral discriminator and does not require any frequency locking between the emitter and the interferometer. Results obtained during test flights show that the backscatter and extinction coefficients at 355 nm can be measured with a relative precision of 10% for 60 m and 240 m vertical resolution, respectively, in aerosol layers of 10-6  m-1 sr-1 backscatter coefficient with a 30-km horizontal resolution. The same relative precision is obtained in cirrus clouds of a 2×10-5  m-1 sr-1 backscatter coefficient for the same vertical resolution and a horizontal resolution reduced to 5 km. The capacity of the system to perform wind velocity measurements is also demonstrated with precisions in the range of 1 to 2  ms-1. Particle-to-total backscatter ratio and line-of-sight speed measurements have been performed on ground echoes; averaged data show biases less than 1% and 0.15  ms-1, respectively. PMID:26479818

  17. Combined Atmospheric and Ocean Profiling from an Airborne High Spectral Resolution Lidar

    NASA Astrophysics Data System (ADS)

    Hair, Johnathan; Hostetler, Chris; Hu, Yongxiang; Behrenfeld, Michael; Butler, Carolyn; Harper, David; Hare, Rich; Berkoff, Timothy; Cook, Antony; Collins, James; Stockley, Nicole; Twardowski, Michael; Cetinić, Ivona; Ferrare, Richard; Mack, Terry

    2016-06-01

    First of its kind combined atmospheric and ocean profile data were collected by the recently upgraded NASA Langley Research Center's (LaRC) High Spectral Resolution Lidar (HSRL-1) during the 17 July - 7 August 2014 Ship-Aircraft Bio-Optical Research Experiment (SABOR). This mission sampled over a region that covered the Gulf of Maine, open-ocean near Bermuda, and coastal waters from Virginia to Rhode Island. The HSRL-1 and the Research Scanning Polarimeter from NASA Goddard Institute for Space Studies collected data onboard the NASA LaRC King Air aircraft and flight operations were closely coordinated with the Research Vessel Endeavor that made in situ ocean optical measurements. The lidar measurements provided profiles of atmospheric backscatter and particulate depolarization at 532nm, 1064nm, and extinction (532nm) from approximately 9km altitude. In addition, for the first time HSRL seawater backscatter, depolarization, and diffuse attenuation data at 532nm were collected and compared to both the ship measurements and the Moderate Resolution Imaging Spectrometer (NASA MODIS-Aqua) satellite ocean retrievals.

  18. Snow measurement system for airborne snow surveys (GPR system from helicopter) in high mountian areas.

    NASA Astrophysics Data System (ADS)

    Sorteberg, Hilleborg K.

    2010-05-01

    In the hydropower industry, it is important to have precise information about snow deposits at all times, to allow for effective planning and optimal use of the water. In Norway, it is common to measure snow density using a manual method, i.e. the depth and weight of the snow is measured. In recent years, radar measurements have been taken from snowmobiles; however, few energy supply companies use this method operatively - it has mostly been used in connection with research projects. Agder Energi is the first Norwegian power producer in using radar tecnology from helicopter in monitoring mountain snow levels. Measurement accuracy is crucial when obtaining input data for snow reservoir estimates. Radar screening by helicopter makes remote areas more easily accessible and provides larger quantities of data than traditional ground level measurement methods. In order to draw up a snow survey system, it is assumed as a basis that the snow distribution is influenced by vegetation, climate and topography. In order to take these factors into consideration, a snow survey system for fields in high mountain areas has been designed in which the data collection is carried out by following the lines of a grid system. The lines of this grid system is placed in order to effectively capture the distribution of elevation, x-coordinates, y-coordinates, aspect, slope and curvature in the field. Variation in climatic conditions are also captured better when using a grid, and dominant weather patterns will largely be captured in this measurement system.

  19. Screening procedure for airborne pollutants emitted from a high-tech industrial complex in Taiwan.

    PubMed

    Wang, John H C; Tsai, Ching-Tsan; Chiang, Chow-Feng

    2015-11-01

    Despite the modernization of computational techniques, atmospheric dispersion modeling remains a complicated task as it involves the use of large amounts of interrelated data with wide variability. The continuously growing list of regulated air pollutants also increases the difficulty of this task. To address these challenges, this study aimed to develop a screening procedure for a long-term exposure scenario by generating a site-specific lookup table of hourly averaged dispersion factors (χ/Q), which could be evaluated by downwind distance, direction, and effective plume height only. To allow for such simplification, the average plume rise was weighted with the frequency distribution of meteorological data so that the prediction of χ/Q could be decoupled from the meteorological data. To illustrate this procedure, 20 receptors around a high-tech complex in Taiwan were selected. Five consecutive years of hourly meteorological data were acquired to generate a lookup table of χ/Q, as well as two regression formulas of plume rise as functions of downwind distance, buoyancy flux, and stack height. To calculate the concentrations for the selected receptors, a six-step Excel algorithm was programmed with four years of emission records and 10 most critical toxics were screened out. A validation check using Industrial Source Complex (ISC3) model with the same meteorological and emission data showed an acceptable overestimate of 6.7% in the average concentration of 10 nearby receptors. The procedure proposed in this study allows practical and focused emission management for a large industrial complex and can therefore be integrated into an air quality decision-making system. PMID:26150196

  20. High-sensitivity converters of a TV type

    NASA Astrophysics Data System (ADS)

    Venediktov, M. D.; Krutyakov, Yu. A.; Plotnikov, M. I.

    1999-06-01

    Three principles of building high sensitive (low-level) converters of a TV-type are well known. They are based on the following: (1) usage of electron-optical image converters (IC) as input image amplifiers and its converting into a TV signal by commercial TV cameras (Fig. 1a); (2) location in a single vacuum volume of a receiving input part of IC with a diode silicon substrate -- a storage target -- in which a photoelectric image is being amplified (amplification factor is 100 . . . 300) and then is read out by an electron beam with the energy corresponding with the condition (sigma) less than 1 ((sigma) -- secondary electron emission coefficient). The converter developed on the base of this principal has got the name of superkremnikon (a super silicon-imaging device) (Fig. 1b); (3) location in a single vacuum volume of a receiving part of IC, amplification microchannel plate (MCP) with amplification factor 100 . . . 1000 and a CCD with amplification equal to 100 (Fig. 1c). One should take into account the following disadvantages of the above-mentioned devices of a TV-type: (1) not high linear resolution of an input image, caused by multiple conversion of an input image - - (2.2 . . . 3.5)(DOT)102 lines in the middle of a target; (2) inadequately high sensitivity, defined basically by optical losses. Limiting sensitivity within the visible range has been realized at superkremnikon (10-7 lx) coupled with an input IC through fiber-optical communication; (4) high cost of the converters, which is limiting their wide practical application for the purposes of medical diagnostics and non- destructive control. The alternative principle of building the high sensitive converters of a TV-type, based on a new method of energy radiation image conversion within a wide spectral range into an electrical (including TV) signal is proposed. In the frames of the new method the MCP is operating at the same time as a receiver, an amplifier and a two-sided storage target on reading out

  1. Airborne LIDAR and high resolution satellite data for rapid 3D feature extraction

    NASA Astrophysics Data System (ADS)

    Jawak, S. D.; Panditrao, S. N.; Luis, A. J.

    2014-11-01

    This work uses the canopy height model (CHM) based workflow for individual tree crown delineation and 3D feature extraction approach (Overwatch Geospatial's proprietary algorithm) for building feature delineation from high-density light detection and ranging (LiDAR) point cloud data in an urban environment and evaluates its accuracy by using very high-resolution panchromatic (PAN) (spatial) and 8-band (multispectral) WorldView-2 (WV-2) imagery. LiDAR point cloud data over San Francisco, California, USA, recorded in June 2010, was used to detect tree and building features by classifying point elevation values. The workflow employed includes resampling of LiDAR point cloud to generate a raster surface or digital terrain model (DTM), generation of a hill-shade image and an intensity image, extraction of digital surface model, generation of bare earth digital elevation model (DEM) and extraction of tree and building features. First, the optical WV-2 data and the LiDAR intensity image were co-registered using ground control points (GCPs). The WV-2 rational polynomial coefficients model (RPC) was executed in ERDAS Leica Photogrammetry Suite (LPS) using supplementary *.RPB file. In the second stage, ortho-rectification was carried out using ERDAS LPS by incorporating well-distributed GCPs. The root mean square error (RMSE) for the WV-2 was estimated to be 0.25 m by using more than 10 well-distributed GCPs. In the second stage, we generated the bare earth DEM from LiDAR point cloud data. In most of the cases, bare earth DEM does not represent true ground elevation. Hence, the model was edited to get the most accurate DEM/ DTM possible and normalized the LiDAR point cloud data based on DTM in order to reduce the effect of undulating terrain. We normalized the vegetation point cloud values by subtracting the ground points (DEM) from the LiDAR point cloud. A normalized digital surface model (nDSM) or CHM was calculated from the LiDAR data by subtracting the DEM from the DSM

  2. Strain patterns deduced from high-resolution airborne surveys in Namibia

    NASA Astrophysics Data System (ADS)

    Ledru, P.; Garoeb, H.; Kamati, T.; Wackerle, R.; Martelet, G.; Truffert, C.

    2003-04-01

    High-resolution aeromagnetic dataset have been acquired in the framework of a long-term programme that aims at a complete coverage of Namibia in 2008. More than half of the territory has been already flown with a 200m line spacing and 2500m tie lines, at a terrain clearance of 80 to 100 m. The contribution of the interpretation of these datasets to the definition of the strain pattern is presented. The first test zone concerns an orogenic zone, the southern zone of the Damara belt, south of Rehoboth. The different maps of the gradients of the magnetic field reduced to the pole have been used in order to define the regional strain pattern. Following up a limited field work that has characterized the geometry and kinematics of the main discontinuities, it has been shown that this zone is characterized by one single orogenic phase marked by a reverse crustal-scale shear zone system (with a down-dip stretching direction) to which regional-scale NE-SW folding is related. The anastomosed shear zone system is thus traced along more than 200 km. A provisional foliation trajectory map can be drawn, transecting the bedding in the hinges of the folds within sediments and underlined by a magnetite-rich veinlet network within the pre-tectonic granites. Moreover, this strain pattern has been extended under the superficial deposits that cover the eastern half of the studied area. Automatic structural analysis has been performed using Geosoft and ArcView/SynArc. Thus, source edge detection, search of ridges and curvature analysis provide qualitative analysis while the search of discontinuities along the horizontal gradients of the magnetic field using SynArc produces a very satisfactory statistical approach of the structural pattern. A second test zone illustrates an extensional tectonic context, i.e. the northern termination of the NNE-SSW Mesozoic aborted rift, developed synchronously with the opening of the Southern Atlantic ocean at the Jurassic-Cretaceous boundary. A dense

  3. An Assessment Of Meso-Scale Hydraulic And Vegetation Characteristics Of The Middle Rio Grande River Using High Resolution Multispectral Airborne Imagery

    NASA Astrophysics Data System (ADS)

    Akasheh, O. Z.; Neale, C. M.

    2004-12-01

    Middle Rio Grande River (MRGR) is the main source of fresh water for the population of New Mexico as well as for irrigated agriculture. Extensive water diversion over the last few decades has affected the composition of the native Riparian vegetation such as Cottonwood population and enhanced the spread of introduced species harmful to the river system like Tamarisk and Russian Olives. High resolution airborne remote sensing is a powerful technique for riparian vegetation mapping and monitoring. Airborne multispectral digital images were acquired over the riparian corridor of the MRGR, New Mexico in June 1999 and July 2001, using the Utah State University (USU) airborne digital imaging system. The imagery were corrected for vignetting effects, geometric lens distortions, rectified to a map base, mosaicked, verified in the field, classified and checked for accuracy. Areas of the vegetation classes and in-stream features were extracted and presented per reach of the river. In this paper a relationship was developed between the total surface water area mapped and both the river water flow rate and water table readings. The consequence of this relationship on riparian vegetation distribution along the river was studied and graphically demonstrated. Strong relationship was found between the total surface water area and water flow rate. In addition the reduction in surface water area resulted in reduction of native trees downstream.

  4. Airborne LIDAR and high resolution satellite data for rapid 3D feature extraction

    NASA Astrophysics Data System (ADS)

    Jawak, S. D.; Panditrao, S. N.; Luis, A. J.

    2014-11-01

    This work uses the canopy height model (CHM) based workflow for individual tree crown delineation and 3D feature extraction approach (Overwatch Geospatial's proprietary algorithm) for building feature delineation from high-density light detection and ranging (LiDAR) point cloud data in an urban environment and evaluates its accuracy by using very high-resolution panchromatic (PAN) (spatial) and 8-band (multispectral) WorldView-2 (WV-2) imagery. LiDAR point cloud data over San Francisco, California, USA, recorded in June 2010, was used to detect tree and building features by classifying point elevation values. The workflow employed includes resampling of LiDAR point cloud to generate a raster surface or digital terrain model (DTM), generation of a hill-shade image and an intensity image, extraction of digital surface model, generation of bare earth digital elevation model (DEM) and extraction of tree and building features. First, the optical WV-2 data and the LiDAR intensity image were co-registered using ground control points (GCPs). The WV-2 rational polynomial coefficients model (RPC) was executed in ERDAS Leica Photogrammetry Suite (LPS) using supplementary *.RPB file. In the second stage, ortho-rectification was carried out using ERDAS LPS by incorporating well-distributed GCPs. The root mean square error (RMSE) for the WV-2 was estimated to be 0.25 m by using more than 10 well-distributed GCPs. In the second stage, we generated the bare earth DEM from LiDAR point cloud data. In most of the cases, bare earth DEM does not represent true ground elevation. Hence, the model was edited to get the most accurate DEM/ DTM possible and normalized the LiDAR point cloud data based on DTM in order to reduce the effect of undulating terrain. We normalized the vegetation point cloud values by subtracting the ground points (DEM) from the LiDAR point cloud. A normalized digital surface model (nDSM) or CHM was calculated from the LiDAR data by subtracting the DEM from the DSM

  5. High-sensitivity molecular organometallic resist for EUV (MORE)

    NASA Astrophysics Data System (ADS)

    Passarelli, James; Murphy, Michael; Del Re, Ryan; Sortland, Miriam; Dousharm, Levi; Vockenhuber, Michaela; Ekinci, Yasin; Neisser, Mark; Freedman, Daniel A.; Brainard, Robert L.

    2015-03-01

    We have developed organometallic carboxylate compounds [RnM(O2CR')2] capable of acting as negativetone EUV resists. Overall, the best and fastest resists contain antimony, are pentavalent and the carboxylate group contains a polymerizable olefin (e.g. acrylate, methacrylate or styrenecarboxylate). Evidence suggests that high sensitivity is achieved through the polymerization of olefins in the exposed region. We have performed a systematic sensitivity study of molecules of the type RnM(O2CR')2 where we have studied seven R groups, four main group metals (M), and three polymerizable carboxylate groups (O2CR'). We found that the greatest predictor of sensitivity of the RnSb(O2CR')2 resists is their level of polymerizable olefins. We mathematically define the polymerizable olefin loading (POL) as the ratio of the number of olefins vs. the number of non-hydrogen atoms. Linear and log plots of Emax vs. POL for a variety of molecules of the type R3Sb(O2CR')2 lend insight into the behaviour of these resists.

  6. Miniaturized superconducting quantum interference magnetometers for high sensitivity applications

    NASA Astrophysics Data System (ADS)

    Granata, C.; Vettoliere, A.; Russo, M.

    2007-09-01

    A miniaturized niobium based dc superconducting quantum interference device (SQUID) magnetometer for high magnetic field sensitivity applications has been developed. The sensing coil consists of an integrated square superconducting coil with a length of 3mm, involving a device area much smaller with respect to the standard SQUID magnetometers with a comparable magnetic field sensitivity; so it allows increasing the spatial resolution keeping the magnetic field sensitivity unaltered. Furthermore, a small pickup coil minimizes its antenna gain, reducing the radio frequency interference. At T =4.2K, the sensors have shown smooth and resonance free V-Φ characteristics and an intrinsic white magnetic field noise spectral density as low as 5.8fT /Hz1/2, measured in flux locked loop configuration. The good agreement with the theoretical predictions guarantees the reliability and the controllability of the sensors. Due to their compactness and good characteristic parameters, such sensors are suitable for large multichannel systems used in biomagnetic imaging.

  7. Highly stretchable and sensitive unidirectional strain sensor via laser carbonization.

    PubMed

    Rahimi, Rahim; Ochoa, Manuel; Yu, Wuyang; Ziaie, Babak

    2015-03-01

    In this paper, we present a simple and low-cost technique for fabricating highly stretchable (up to 100% strain) and sensitive (gauge factor of up to 20 000) strain sensors. Our technique is based on transfer and embedment of carbonized patterns created through selective laser pyrolization of thermoset polymers, such as polyimide, into elastomeric substrates (e.g., PDMS or Ecoflex). Embedded carbonized materials are composed of partially aligned graphene and carbon nanotube (CNT) particles and show a sharp directional anisotropy, which enables the fabrication of extremely robust, highly stretchable, and unidirectional strain sensors. Raman spectrum of pyrolized carbon regions reveal that under optimal laser settings, one can obtain highly porous carbon nano/microparticles with sheet resistances as low as 60 Ω/□. Using this technique, we fabricate an instrumented latex glove capable of measuring finger motion in real-time. PMID:25686021

  8. Optimal attributes for the object based detection of giant reed in riparian habitats: A comparative study between Airborne High Spatial Resolution and WorldView-2 imagery

    NASA Astrophysics Data System (ADS)

    Fernandes, Maria Rosário; Aguiar, Francisca C.; Silva, João M. N.; Ferreira, Maria Teresa; Pereira, José M. C.

    2014-10-01

    Giant reed is an aggressive invasive plant of riparian ecosystems in many sub-tropical and warm-temperate regions, including Mediterranean Europe. In this study we tested a set of geometric, spectral and textural attributes in an object based image analysis (OBIA) approach to map giant reed invasions in riparian habitats. Bagging Classification and Regression Tree were used to select the optimal attributes and to build the classification rules sets. Mapping accuracy was performed using landscape metrics and the Kappa coefficient to compare the topographical and geometric similarity between the giant reed patches obtained with the OBIA map and with a validation map derived from on-screen digitizing. The methodology was applied in two high spatial resolution images: an airborne multispectral imagery and the newly WorldView-2 imagery. A temporal coverage of the airborne multispectral images was radiometrically calibrated with the IR-Mad transformation and used to assess the influence of the phenological variability of the invader. We found that optimal attributes for giant reed OBIA detection are a combination of spectral, geometric and textural information, with different scoring selection depending on the spectral and spatial characteristics of the imagery. WorldView-2 showed higher mapping accuracy (Kappa coefficient of 77%) and spectral attributes, including the newly yellow band, were preferentially selected, although a tendency to overestimate the total invaded area, due to the low spatial resolution (2 m of pixel size vs. 50 cm) was observed. When airborne images were used, geometric attributes were primarily selected and a higher spatial detail of the invasive patches was obtained, due to the higher spatial resolution. However, in highly heterogeneous landscapes, the low spectral resolution of the airborne images (4 bands instead of the 8 of WorldView-2) reduces the capability to detect giant reed patches. Giant reed displays peculiar spectral and geometric

  9. Highly strain-sensitive magnetostrictive tunnel magnetoresistance junctions

    NASA Astrophysics Data System (ADS)

    Tavassolizadeh, Ali; Hayes, Patrick; Rott, Karsten; Reiss, Günter; Quandt, Eckhard; Meyners, Dirk

    2015-06-01

    Tunnel magnetoresistance (TMR) junctions with CoFeB/MgO/CoFeB layers are promising for strain sensing applications due to their high TMR effect and magnetostrictive sense layer (CoFeB). TMR junctions available even in submicron dimensions can serve as strain sensors for microelectromechanical systems devices. Upon stress application, the magnetization configuration of such junctions changes due to the inverse magnetostriction effect resulting in strain-sensitive tunnel resistance. Here, strain sensitivity of round-shaped junctions with diameters of 11.3 μm, 19.2 μm, 30.5 μm, and 41.8 μm were investigated on macroscopic cantilevers using a four-point bending apparatus. This investigation mainly focuses on changes in hard-axis TMR loops caused by the stress-induced anisotropy. A macrospin model is proposed, supported by micromagnetic simulations, which describes the complete rotation of the sense layer magnetization within TMR loops of junctions, exposed to high stress. Below 0.2‰ tensile strain, a representative junction with 30.5 μm diameter exhibits a very large gauge factor of 2150. For such high gauge factor a bias field H = - 3.2 kA / m is applied in an angle equal to 3 π / 2 toward the pinned magnetization of the reference layer. The strain sensitivity strongly depends on the bias field. Applying stress along π / 4 against the induced magnetocrystalline anisotropy, both compressive and tensile strain can be identified by a unique sensor. More importantly, a configuration with a gauge factor of 400 at zero bias field is developed which results in a straightforward and compact measuring setup.

  10. Ultra-high sensitivity moment magnetometry of geological samples

    NASA Astrophysics Data System (ADS)

    Andrade Lima, E.; Weiss, B. P.

    2012-12-01

    Scanning SQUID microscopy offers a unique combination of high spatial resolution and magnetic field sensitivity that allows for the detection of magnetic moments as weak as 10^-16 Am2. This opens the possibility of extending paleomagnetic analyses to samples that have not been accessible to standard moment magnetometry, for which the detection limit is 10^-12 Am2. Of particular interest are individual terrestrial and extraterrestrial particles of small size (< 500 μm) that may preserve records of planetary dynamos and early nebular magnetic fields. Example targets include impact melt spherules, zircon and other silicate crystals, micrometeorites, cosmic dust, chondrules and refractory inclusions. These grains may be adequately modeled as small uniformly magnetized volumes, such that retrieving their magnetic moments from measured magnetic field maps does not require solving non-unique inverse problems. As a consequence, SQUID microscopes can be utilized as ultra-high sensitivity moment magnetometers. We show alternating field and thermal demagnetization data for several grains that demonstrate the performance of this technique. In addition, we compare scanning SQUID microscopy data with net moment measurements of the same samples performed by a commercial superconducting rock magnetometer. The results agree for stronger moments, as expected, but rapidly diverge as net moments fall below the lower 10^-10 Am2 range. These studies underscore the inability of conventional instruments not only to detect very weak moments but also to isolate contamination originating from background sources such as sample holders and mounts. We expect ultra-high sensitivity moment magnetometry using scanning SQUID microscopy will be a powerful tool in helping elucidate the formation of the solar system and planetary history.

  11. The Georgia Tech High Sensitivity Microwave Measurement System

    NASA Technical Reports Server (NTRS)

    Deboer, David R.; Steffes, Paul G.

    1996-01-01

    As observations and models of the planets become increasingly more accurate and sophisticated, the need for highly accurate laboratory measurements of the microwave properties of the component gases present in their atmospheres become ever more critical. This paper describes the system that has been developed at Georgia Tech to make these measurements at wavelengths ranging from 13.3 cm to 1.38 cm with a sensitivity of 0.05 dB/km at the longest wavelength and 0.6 db/km at the shortest wavelength.

  12. High sensitivity charge amplifier for ion beam uniformity monitor

    DOEpatents

    Johnson, Gary W.

    2001-01-01

    An ion beam uniformity monitor for very low beam currents using a high-sensitivity charge amplifier with bias compensation. The ion beam monitor is used to assess the uniformity of a raster-scanned ion beam, such as used in an ion implanter, and utilizes four Faraday cups placed in the geometric corners of the target area. Current from each cup is integrated with respect to time, thus measuring accumulated dose, or charge, in Coulombs. By comparing the dose at each corner, a qualitative assessment of ion beam uniformity is made possible. With knowledge of the relative area of the Faraday cups, the ion flux and areal dose can also be obtained.

  13. Highly sensitive automated setup for measuring surface photovoltage spectra

    NASA Astrophysics Data System (ADS)

    Germanova, K.; Nikolov, L.; Hardalov, Ch.

    1989-04-01

    We present an automated experimental setup for dc measurement of surface photovoltage (SPV) spectra in wide spectral and/or temperature ranges. A Pt boss, sealed on a bimorphic piezoelement, has been used as a small area vibrating electrode and a programmable digital-to-analog convertor (DAC) as a source of compensation. In addition, a combination of automatic data acquisition and statistical analysis has been applied, thus ensuring reliability and stability of SPV measurements. Moreover, the automated setup provides a high sensitivity and objectivity of SPV investigations.

  14. Recovery of atmospheric water vapor total column abundance from imaging spectrometer data around 940 nm - Sensitivity analysis and application to Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data

    NASA Technical Reports Server (NTRS)

    Carrere, Veronique; Conel, James E.

    1993-01-01

    Two simple techniques (Continuum Interpolated Band Ratio, CIBR, and Narrow/Wide ratio, N/W) to retrieve path precipitable water from AVIRIS high spectral resolution radiance data using the 940 nm water absorption band are compared. A sensitivity analysis was performed using the radiative transfer code LOWTRAN 7 to determine which one of these two approaches will provide a better estimate over land and water areas. The CIBR proved to be the technique less sensitive to perturbing effects, except for errors in visibility estimate. Both techniques were applied to AVIRIS radiance data acquired over Salton Sea, California. Resulting images confirmed that the use of a constant gray reflectance in the model led to a higher overestimation of the amount of water retrieved for N/W over vegetated areas. Validation was performed through comparison between an independent estimate of water vapor from concurrent Reagan sunphotometer measurements and AVIRIS estimates. Amounts retrieved using the N/W approach match more closely in situ measurements, even after adjusting model parameters for background reflectance, viewing geometry, and type of aerosol at the site.

  15. High-Sensitivity Measurement of Density by Magnetic Levitation.

    PubMed

    Nemiroski, Alex; Kumar, A A; Soh, Siowling; Harburg, Daniel V; Yu, Hai-Dong; Whitesides, George M

    2016-03-01

    This paper presents methods that use Magnetic Levitation (MagLev) to measure very small differences in density of solid diamagnetic objects suspended in a paramagnetic medium. Previous work in this field has shown that, while it is a convenient method, standard MagLev (i.e., where the direction of magnetization and gravitational force are parallel) cannot resolve differences in density <10(-4) g/cm(3) for macroscopic objects (>mm) because (i) objects close in density prevent each other from reaching an equilibrium height due to hard contact and excluded volume, and (ii) using weaker magnets or reducing the magnetic susceptibility of the medium destabilizes the magnetic trap. The present work investigates the use of weak magnetic gradients parallel to the faces of the magnets as a means of increasing the sensitivity of MagLev without destabilization. Configuring the MagLev device in a rotated state (i.e., where the direction of magnetization and gravitational force are perpendicular) relative to the standard configuration enables simple measurements along the axes with the highest sensitivity to changes in density. Manipulating the distance of separation between the magnets or the lengths of the magnets (along the axis of measurement) enables the sensitivity to be tuned. These modifications enable an improvement in the resolution up to 100-fold over the standard configuration, and measurements with resolution down to 10(-6) g/cm(3). Three examples of characterizing the small differences in density among samples of materials having ostensibly indistinguishable densities-Nylon spheres, PMMA spheres, and drug spheres-demonstrate the applicability of rotated Maglev to measuring the density of small (0.1-1 mm) objects with high sensitivity. This capability will be useful in materials science, separations, and quality control of manufactured objects. PMID:26815205

  16. Highly sensitive electronically modulated photoacoustic spectrometer for ozone detection.

    PubMed

    Gondal, M A; Yamani, Z H

    2007-10-10

    An ozone (O(3)) gas sensor with a sensitivity of parts per 10(9) (ppb) level and a high level of selectivity based on the resonant photoacoustic effect was developed using an electronically modulated cw CO(2) laser beam. Quite different from the standard chopper modulation of a laser beam, here the laser source was electronically modulated to overcome the inherent problem of frequency instability associated with chopper modulation. With electronic modulation, in conjunction with the fast Fourier transform (FFT) of transient signals, we were able to improve significantly the sensitivity of the photoacoustic (PA) system for the detection of O(3). In addition to the improved sensitivity, our method proved that the FFT of a laser modulated PA signal could suppress the noise signal generated by spurious window diffused absorption, which in the case of most commonly used lock-in techniques is rather unavoidable. The dependence of the PA signal on various experimental parameters such as buffer gas, laser power, modulation frequency, and trace gas concentration was investigated. In the case of buffer gas, argon proved to be more suitable than nitrogen and helium in terms of enhancing the sensitivity of the system. The limits of detection of O(3) using the 9 P(14) CO(2) laser line in our PA system are 5 parts per 10(9) by volume (ppbv) and 14 ppbv with electronic and standard chopper modulation, respectively. This detection limit of O(3) is quite applicable for detection of safe levels of O(3), at ground level. PMID:17932514

  17. High resolution mapping of the tropospheric NO2 distribution in three Belgian cities based on airborne APEX remote sensing

    NASA Astrophysics Data System (ADS)

    Tack, Frederik; Merlaud, Alexis; Fayt, Caroline; Danckaert, Thomas; Iordache, Daniel; Meuleman, Koen; Deutsch, Felix; Adriaenssens, Sandy; Fierens, Frans; Van Roozendael, Michel

    2015-04-01

    An approach is presented to retrieve tropospheric nitrogen dioxide (NO2) vertical column densities (VCDs) and to map the NO2 two dimensional distribution at high resolution, based on Airborne Prism EXperiment (APEX) observations. APEX, developed by a Swiss-Belgian consortium on behalf of ESA (European Space Agency), is a pushbroom hyperspectral imager with a high spatial (approximately 3 m at 5000 m ASL), spectral (413 to 2421 nm in 533 narrow, contiguous spectral bands) and radiometric (14-bit) resolution. VCDs are derived, following a similar approach as described in the pioneering work of Popp et al. (2012), based on (1) spectral calibration and spatial binning of the observed radiance spectra in order to improve the spectral resolution and signal-to-noise ratio, (2) Differential Optical Absorption Spectroscopy (DOAS) analysis of the pre-processed spectra in the visible wavelength region, with a reference spectrum containing low NO2 absorption, in order to quantify the abundance of NO2 along the light path, based on its molecular absorption structures and (3) radiative transfer modeling for air mass factor calculation in order to convert slant to vertical columns. This study will be done in the framework of the BUMBA (Belgian Urban NO2 Monitoring Based on APEX hyperspectral data) project. Dedicated flights with APEX mounted in a Dornier DO-228 airplane, operated by Deutsches Zentrum für Luft- und Raumfahrt (DLR), are planned to be performed in Spring 2015 above the three largest and most heavily polluted Belgian cities, i.e. Brussels, Antwerp and Liège. The retrieved VCDs will be validated by comparison with correlative ground-based and car-based DOAS observations. Main objectives are (1) to assess the operational capabilities of APEX to map the NO2 field over an urban area at high spatial and spectral resolution in a relatively short time and cost-effective way, and to characterise all aspects of the retrieval approach; (2) to use the APEX NO2 measurements

  18. High Sensitivity Surface Enhanced Raman Scattering Detection of Tryptophan

    NASA Astrophysics Data System (ADS)

    Kandakkathara, Archana

    Raman spectroscopy has the capability of providing detailed information about molecular structure, but the extremely small cross section of Raman scattering prevents this technique from applications requiring high sensitivity. Surface enhanced Raman scattering (SERS) on the other hand provides strongly increased Raman signal from molecules attached to metallic nanostructures. SERS is thus a promising technique for high sensitivity analytical applications. One particular area of interest is the application of such techniques for the analysis of the composition of biological cells. However, there are issues which have to be addressed in order to make SERS a reliable technique such as the optimization of conditions for any given analyte, understanding the kinetic processes of binding of the target molecules to the nanostructures and understanding the evolution and coagulation of the nanostructures, in the case of colloidal solutions. The latter processes introduce a delay time for the observation of maximum enhancement factors which must be taken into account for any given implementation of SERS. In the present thesis the goal was to develop very sensitive SERS techniques for the measurement of biomolecules of interest for analysis of the contents of cells. The techniques explored could be eventually be applicable to microfluidic systems with the ultimate goal of analyzing the molecular constituents of single cells. SERS study of different amino acids and organic dyes were performed during the course of this thesis. A high sensitivity detection system based on SERS has been developed and spectrum from tryptophan (Trp) amino acid at very low concentration (10-8 M) has been detected. The concentration at which good quality SERS spectra could be detected from Trp is 4 orders of magnitude smaller than that previously reported in literature. It has shown that at such low concentrations the SERS spectra of Trp are qualitatively distinct from the spectra commonly reported in

  19. High pressure-sensitive gene expression in Lactobacillus sanfranciscensis.

    PubMed

    Vogel, R F; Pavlovic, M; Hörmann, S; Ehrmann, M A

    2005-08-01

    Lactobacillus sanfranciscensis is a Gram-positive lactic acid bacterium used in food biotechnology. It is necessary to investigate many aspects of a model organism to elucidate mechanisms of stress response, to facilitate preparation, application and performance in food fermentation, to understand mechanisms of inactivation, and to identify novel tools for high pressure biotechnology. To investigate the mechanisms of the complex bacterial response to high pressure we have analyzed changes in the proteome and transcriptome by 2-D electrophoresis, and by microarrays and real time PCR, respectively. More than 16 proteins were found to be differentially expressed upon high pressure stress and were compared to those sensitive to other stresses. Except for one apparently high pressure-specific stress protein, no pressure-specific stress proteins were found, and the proteome response to pressure was found to differ from that induced by other stresses. Selected pressure-sensitive proteins were partially sequenced and their genes were identified by reverse genetics. In a transcriptome analysis of a redundancy cleared shot gun library, about 7% of the genes investigated were found to be affected. Most of them appeared to be up-regulated 2- to 4-fold and these results were confirmed by real time PCR. Gene induction was shown for some genes up-regulated at the proteome level (clpL/groEL/rbsK), while the response of others to high hydrostatic pressure at the transcriptome level seemed to differ from that observed at the proteome level. The up-regulation of selected genes supports the view that the cell tries to compensate for pressure-induced impairment of translation and membrane transport. PMID:16082466

  20. Advances in High Energy Solid-State Pulsed 2-micron Lidar Development for Ground and Airborne Wind, Water Vapor and CO2 Measurements

    NASA Astrophysics Data System (ADS)

    Singh, Upendra; Yu, Jirong; Petros, Mulugeta; Refaat, Tamer; Kavaya, Michael; Remus, Ruben

    2015-04-01

    NASA Langley Research Center has a long history of developing 2 µm lasers. From fundamental spectroscopy research, theoretical prediction of new materials, laser demonstration and engineering of lidar systems, it has been a very successful program spanning around two decades. Successful development of 2 µm lasers has led to development of a state-of-the-art compact lidar transceiver for a pulsed coherent Doppler lidar system for wind measurement with an unprecedented laser pulse energy of 250-mJ in a rugged package. This high pulse energy is produced by a Ho:Tm:LuLiF laser with an optical amplifier. While the lidar is meant for use as an airborne instrument, ground-based tests were carried out to characterize performance of the lidar. Atmospheric measurements will be presented, showing the lidar's capability for wind measurement in the atmospheric boundary layer and free troposphere. Lidar wind measurements are compared to a balloon sonde, showing good agreement between the two sensors. Similar architecture has been used to develop a high energy, Ho:Tm:YLF double-pulsed 2 μm Integrated Differential Absorption Lidar (IPDA) instrument based on direct detection technique that provides atmospheric column CO2 measurements. This instrument has been successfully used to measure atmospheric CO2 column density initially from a ground mobile lidar trailer, and then it was integrated on B-200 plane and 20 hrs of flight measurement were made from an altitude ranging 1500 meter to 8000 meter. These measurements were compared to in-situ measurements and NOAA airborne flask measurement to derive the dry mixing ratio of the column CO2 by reflecting the signal by various reflecting surfaces such as land, vegetation, ocean surface, snow and sand. The lidar measurements when compared showed a very agreement with in-situ and airborne flask measurement. NASA Langley Research Center is currently developing a triple-pulsed 2 μm Integrated Differential Absorption Lidar (IPDA

  1. Advances in High Energy Solid-State Pulsed 2-Micron Lidar Development for Ground and Airborne Wind, Water Vapor and CO2 Measurements

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta; Refaat, Tamer; Kavaya, Michael J.; Remus, Ruben

    2015-01-01

    NASA Langley Research Center has a long history of developing 2-micron lasers. From fundamental spectroscopy research, theoretical prediction of new materials, laser demonstration and engineering of lidar systems, it has been a very successful program spanning around two decades. Successful development of 2-micron lasers has led to development of a state-of-the-art compact lidar transceiver for a pulsed coherent Doppler lidar system for wind measurement with an unprecedented laser pulse energy of 250 millijoules in a rugged package. This high pulse energy is produced by a Ho:Tm:LuLiF laser with an optical amplifier. While the lidar is meant for use as an airborne instrument, ground-based tests were carried out to characterize performance of the lidar. Atmospheric measurements will be presented, showing the lidar's capability for wind measurement in the atmospheric boundary layer and free troposphere. Lidar wind measurements are compared to a balloon sonde, showing good agreement between the two sensors. Similar architecture has been used to develop a high energy, Ho:Tm:YLF double-pulsed 2-micron Integrated Differential Absorption Lidar (IPDA) instrument based on direct detection technique that provides atmospheric column CO2 measurements. This instrument has been successfully used to measure atmospheric CO2 column density initially from a ground mobile lidar trailer, and then it was integrated on B-200 plane and 20 hours of flight measurement were made from an altitude ranging 1500 meters to 8000 meters. These measurements were compared to in-situ measurements and National Oceanic and Atmospheric Administration (NOAA) airborne flask measurement to derive the dry mixing ratio of the column CO2 by reflecting the signal by various reflecting surfaces such as land, vegetation, ocean surface, snow and sand. The lidar measurements when compared showed a very agreement with in-situ and airborne flask measurement. NASA Langley Research Center is currently developing a

  2. ALMA: Millimeter/submillimeter Astronomy at high sensitivity and resolution

    NASA Astrophysics Data System (ADS)

    Wootten, Alwyn; Corder, Stuartt Alan; Iono, Daisuke; Testi, Leonardo

    2015-08-01

    Vigorous and transformative investigation of the millimeter/submillimeter sky at high sensitivity and high resolution has benefitted from the recent completion of the Atacama Large Millimeter/submillimeter Array (ALMA), an effort of 22 countries. ALMA, a versatile interferometric telescope at 5000m elevation in the Atacama Desert of northern Chile, is comprised of sixty-six precision telescopes which may be arrayed over a 16 km extent on the high Chajnantor plain. Owing to its large collecting area of over 6600m^2 and its commodious spectral grasp of 8 GHz of spectrum in dual polarizations within an 84-950 GHz range, ALMA provides astronomers with vastly improved spectroscopic sensitivity. Spatial resolutions of 30 milliarcsec were demonstrated recently, revealing rings within the HL Tau protoplanetary disk, the rotating structure of the asteroid Juno and the molecular structure of the z~3 lensed galaxy SDP.81. The astrometric accuracy even at this early stage of deployment is better than 3 milliarcsec, providing improved ephemerides for the encounter of the New Horizons spacecraft with the Pluto-Charon system. Very long baseline capability is expected to bring microarcsecond imaging to a worldwide array anchored by ALMA with potential for imaging nearby Black Holes on the scales of their Event Horizons.ALMA's huge collecting area has enabled detection of lines of C, N and CO and continuum for characterization of massive complexes near the Era of Recombination. ALMA's sensitivity and resolution have enabledmeasurement of molecular emission through cosmic time from numerous molecules characterizing galactic star-forming regions and tracing their kinematics near active nuclei, starbursts, interacting clouds and quiescent disks. ALMA's sensitivity, resolution and spectral grasp have enabled it to image molecules and dust characterizing circumstellar disks and embedded bodies in protostellar, transition and debris stages of development.ALMA is a partnership of ESO

  3. Airborne radioactive contamination monitoring

    SciTech Connect

    Whitley, C.R.; Adams, J.R.; Bounds, J.A.; MacArthur, D.W.

    1996-03-01

    Current technologies for the detection of airborne radioactive contamination do not provide real-time capability. Most of these techniques are based on the capture of particulate matter in air onto filters which are then processed in the laboratory; thus, the turnaround time for detection of contamination can be many days. To address this shortcoming, an effort is underway to adapt LRAD (Long-Range-Alpha-Detection) technology for real-time monitoring of airborne releases of alpa-emitting radionuclides. Alpha decays in air create ionization that can be subsequently collected on electrodes, producing a current that is proportional to the amount of radioactive material present. Using external fans on a pipe containing LRAD detectors, controlled samples of ambient air can be continuously tested for the presence of radioactive contamination. Current prototypes include a two-chamber model. Sampled air is drawn through a particulate filter and then through the first chamber, which uses an electrostatic filter at its entrance to remove ambient ionization. At its exit, ionization that occurred due to the presence of radon is collected and recorded. The air then passes through a length of pipe to allow some decay of short-lived radon species. A second chamber identical to the first monitors the remaining activity. Further development is necessary on air samples without the use of particulate filtering, both to distinguish ionization that can pass through the initial electrostatic filter on otherwise inert particulate matter from that produced through the decay of radioactive material and to separate both of these from the radon contribution. The end product could provide a sensitive, cost-effective, real-time method of determining the presence of airborne radioactive contamination.

  4. Coumarin-bearing triarylamine sensitizers with high molar extinction coefficient for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Zhong, Changjian; Gao, Jianrong; Cui, Yanhong; Li, Ting; Han, Liang

    2015-01-01

    Coumarin unit is introduced into triarylamine and three organic sensitizers are designed and synthesized with triarylamine bearing coumarin moiety as the electron donor, conjugated system containing thiophene unit as the π-bridge, and cyanoacetic acid moiety as the electron acceptor. The light-harvesting capabilities and photovoltaic performance of these dyes are investigated systematically with the comparison of different π-bridges. High molar extinction coefficients are observed in these triarylamine dyes and the photocurrent and photovoltage are increased with the introduction of another thiophene or benzene. Optimal photovoltaic performance (η = 6.24%, Voc = 690 mV, Jsc = 14.33 mA cm-2, and ff = 0.63) is observed in the DSSC based on dye with thiophene-phenyl unit as the π-conjugated bridge under 100 mW cm-2 simulated AM 1.5 G solar irradiation.

  5. High refractive index and temperature sensitivity LPGs for high temperature operation

    NASA Astrophysics Data System (ADS)

    Nascimento, I. M.; Gouveia, C.; Jana, Surnimal; Bera, Susanta; Baptista, J. M.; Moreira, Paulo; Biwas, Palas; Bandyopadhyay, Somnath; Jorge, Pedro A. S.

    2013-11-01

    A fiber optic sensor for high sensitivity refractive index and temperature measurement able to withstand temperature up to 450 °C is reported. Two identical LPG gratings were fabricated, whereas one was coated with a high refractive index (~1.78) sol-gel thin film in order to increase its sensitivity to the external refractive index. The two sensors were characterized and compared in refractive index and temperature. Sensitivities of 1063 nm/RIU (1.338 - 1.348) and 260 pm/°C were achieved for refractive index and temperature, respectively.

  6. High-sensitivity acoustic sensors from nanofibre webs

    PubMed Central

    Lang, Chenhong; Fang, Jian; Shao, Hao; Ding, Xin; Lin, Tong

    2016-01-01

    Considerable interest has been devoted to converting mechanical energy into electricity using polymer nanofibres. In particular, piezoelectric nanofibres produced by electrospinning have shown remarkable mechanical energy-to-electricity conversion ability. However, there is little data for the acoustic-to-electric conversion of electrospun nanofibres. Here we show that electrospun piezoelectric nanofibre webs have a strong acoustic-to-electric conversion ability. Using poly(vinylidene fluoride) as a model polymer and a sensor device that transfers sound directly to the nanofibre layer, we show that the sensor devices can detect low-frequency sound with a sensitivity as high as 266 mV Pa−1. They can precisely distinguish sound waves in low to middle frequency region. These features make them especially suitable for noise detection. Our nanofibre device has more than five times higher sensitivity than a commercial piezoelectric poly(vinylidene fluoride) film device. Electrospun piezoelectric nanofibres may be useful for developing high-performance acoustic sensors. PMID:27005010

  7. High-sensitivity acoustic sensors from nanofibre webs.

    PubMed

    Lang, Chenhong; Fang, Jian; Shao, Hao; Ding, Xin; Lin, Tong

    2016-01-01

    Considerable interest has been devoted to converting mechanical energy into electricity using polymer nanofibres. In particular, piezoelectric nanofibres produced by electrospinning have shown remarkable mechanical energy-to-electricity conversion ability. However, there is little data for the acoustic-to-electric conversion of electrospun nanofibres. Here we show that electrospun piezoelectric nanofibre webs have a strong acoustic-to-electric conversion ability. Using poly(vinylidene fluoride) as a model polymer and a sensor device that transfers sound directly to the nanofibre layer, we show that the sensor devices can detect low-frequency sound with a sensitivity as high as 266 mV Pa(-1). They can precisely distinguish sound waves in low to middle frequency region. These features make them especially suitable for noise detection. Our nanofibre device has more than five times higher sensitivity than a commercial piezoelectric poly(vinylidene fluoride) film device. Electrospun piezoelectric nanofibres may be useful for developing high-performance acoustic sensors. PMID:27005010

  8. Highly Sensitive Assay for Measurement of Arenavirus-cell Attachment.

    PubMed

    Klaus, Joseph P; Botten, Jason

    2016-01-01

    Arenaviruses are a family of enveloped RNA viruses that cause severe human disease. The first step in the arenavirus life cycle is attachment of viral particles to host cells. While virus-cell attachment can be measured through the use of virions labeled with biotin, radioactive isotopes, or fluorescent dyes, these approaches typically require high multiplicities of infection (MOI) to enable detection of bound virus. We describe a quantitative (q)RT-PCR-based assay that measures Junin virus strain Candid 1 attachment via quantitation of virion-packaged viral genomic RNA. This assay has several advantages including its extreme sensitivity and ability to measure attachment over a large dynamic range of MOIs without the need to purify or label input virus. Importantly, this approach can be easily tailored for use with other viruses through the use of virus-specific qRT-PCR reagents. Further, this assay can be modified to permit measurement of particle endocytosis and genome uncoating. In conclusion, we describe a simple, yet robust assay for highly sensitive measurement of arenavirus-cell attachment. PMID:26966937

  9. Ultra-Sensitive, High Throughput and Quantitative Proteomics Measurements

    SciTech Connect

    Jacobs, Jon M.; Monroe, Matthew E.; Qian, Weijun; Shen, Yufeng; Anderson, Gordon A.; Smith, Richard D.

    2005-02-01

    We describe the broad basis and application of an approach for very high throughput, ultra-sensitive, and quantitative proteomic measurements based upon the use of ultra-high performance separations and mass spectrometry. An overview of the accurate mass and time (AMT) tag approach and a description of the incorporated data analysis pipeline necessary for efficient proteomic studies are presented. Adjunct technologies, including stable-isotope labeling methodologies and improvements in the utilization of LC-MS peak intensity information for quantitative purposes are discussed. Related areas include the use of automated sample handling for improving analysis reproducibility, methods for using information from the separation for more confident peptide peak identification, and the utilization of smaller diameter capillary columns having lower volumetric flow rates to increase electrospray ionization efficiency and allow for more predictable and quantitative results. The developments are illustrated in the context of studies of complex biological systems.

  10. Wide bandwidth transimpedance amplifier for extremely high sensitivity continuous measurements

    NASA Astrophysics Data System (ADS)

    Ferrari, Giorgio; Sampietro, Marco

    2007-09-01

    This article presents a wide bandwidth transimpedance amplifier based on the series of an integrator and a differentiator stage, having an additional feedback loop to discharge the standing current from the device under test (DUT) to ensure an unlimited measuring time opportunity when compared to switched discharge configurations while maintaining a large signal amplification over the full bandwidth. The amplifier shows a flat response from 0.6Hzto1.4MHz, the capability to operate with leakage currents from the DUT as high as tens of nanoamperes, and rail-to-rail dynamic range for sinusoidal current signals independent of the DUT leakage current. Also available is a monitor output of the stationary current to track experimental slow drifts. The circuit is ideal for noise spectral and impedance measurements of nanodevices and biomolecules when in the presence of a physiological medium and in all cases where high sensitivity current measurements are requested such as in scanning probe microscopy systems.

  11. Hydrophilic packaging of iron oxide nanoclusters for highly sensitive imaging.

    PubMed

    Smith, Cartney E; Ernenwein, Dawn; Shkumatov, Artem; Clay, Nicholas E; Lee, JuYeon; Melhem, Molly; Misra, Sanjay; Zimmerman, Steven C; Kong, Hyunjoon

    2015-11-01

    Superparamagnetic iron oxide nanoparticles (SPIONs) are used as imaging probes to provide contrast in magnetic resonance images. Successful use of SPIONs in targeted applications greatly depends on their ability to generate contrast, even at low levels of accumulation, in the tissue of interest. In the present study, we report that SPION nanoclusters packaged to a controlled size by a hyperbranched polyglycerol (HPG) can target tissue defects and have a high relaxivity of 719 mM(-1) s(-1), which was close to their theoretical maximal limit. The resulting nanoclusters were able to identify regions of defective vasculature in an ischemic murine hindlimb using MRI with iron doses that were 5-10 fold lower than those typically used in preclinical studies. Such high relaxivity was attributed to the molecular architecture of HPG, which mimics that of the water retentive polysaccharide, glycogen. The results of this study will be broadly useful in sensitive imaging applications. PMID:26291408

  12. Highly efficient monolithic dye-sensitized solar cells.

    PubMed

    Kwon, Jeong; Park, Nam-Gyu; Lee, Jun Young; Ko, Min Jae; Park, Jong Hyeok

    2013-03-01

    Monolithic dye-sensitized solar cells (M-DSSCs) provide an effective way to reduce the fabrication cost of general DSSCs since they do not require transparent conducting oxide substrates for the counter electrode. However, conventional monolithic devices have low efficiency because of the impediments resulting from counter electrode materials and spacer layers. Here, we demonstrate highly efficient M-DSSCs featuring a highly conductive polymer combined with macroporous polymer spacer layers. With M-DSSCs based on a PEDOT/polymer spacer layer, a power conversion efficiency of 7.73% was achieved, which is, to the best of our knowledge, the highest efficiency for M-DSSCs to date. Further, PEDOT/polymer spacer layers were applied to flexible DSSCs and their cell performance was investigated. PMID:23432389

  13. Highly sensitive detection of urinary cadmium to assess personal exposure.

    PubMed

    Argun, Avni A; Banks, Ashley M; Merlen, Gwendolynne; Tempelman, Linda A; Becker, Michael F; Schuelke, Thomas; Dweik, Badawi M

    2013-04-22

    A series of Boron-Doped Diamond (BDD) ultramicroelectrode arrays were fabricated and investigated for their performance as electrochemical sensors to detect trace level metals such as cadmium. The steady-state diffusion behavior of these sensors was validated using cyclic voltammetry followed by electrochemical detection of cadmium in water and in human urine to demonstrate high sensitivity (>200 μA ppb(-1) cm(-2)) and low background current (<4 nA). When an array of ultramicroelectrodes was positioned with optimal spacing, these BDD sensors showed a sigmoidal diffusion behavior. They also demonstrated high accuracy with linear dose dependence for quantification of cadmium in a certified reference river water sample from the U.S. National Institute of Standards and Technology (NIST) as well as in a human urine sample spiked with 0.25-1 ppb cadmium. PMID:23561905

  14. High-Sensitivity Temperature-Independent Silicon Photonic Microfluidic Biosensors

    NASA Astrophysics Data System (ADS)

    Kim, Kangbaek

    Optical biosensors that can precisely quantify the presence of specific molecular species in real time without the need for labeling have seen increased use in the drug discovery industry and molecular biology in general. Of the many possible optical biosensors, the TM mode Si biosensor is shown to be very attractive in the sensing application because of large field amplitude on the surface and cost effective CMOS VLSI fabrication. Noise is the most fundamental factor that limits the performance of sensors in development of high-sensitivity biosensors, and noise reduction techniques require precise studies and analysis. One such example stems from thermal fluctuations. Generally SOI biosensors are vulnerable to ambient temperature fluctuations because of large thermo-optic coefficient of silicon (˜2x10 -4 RIU/K), typically requiring another reference ring and readout sequence to compensate temperature induced noise. To address this problem, we designed sensors with a novel TM-mode shallow-ridge waveguide that provides both large surface amplitude for bulk and surface sensing. With proper design, this also provides large optical confinement in the aqueous cladding that renders the device athermal using the negative thermo-optic coefficient of water (~ --1x10-4RIU/K), demonstrating cancellation of thermo-optic effects for aqueous solution operation near 300K. Additional limitations resulting from mechanical actuator fluctuations, stability of tunable lasers, and large 1/f noise of lasers and sensor electronics can limit biosensor performance. Here we also present a simple harmonic feedback readout technique that obviates the need for spectrometers and tunable lasers. This feedback technique reduces the impact of 1/f noise to enable high-sensitivity, and a DSP lock-in with 256 kHz sampling rate can provide down to micros time scale monitoring for fast transitions in biomolecular concentration with potential for small volume and low cost. In this dissertation, a novel

  15. Processing of High Resolution, Multiparametric Radar Data for the Airborne Dual-Frequency Precipitation Radar APR-2

    NASA Technical Reports Server (NTRS)

    Tanelli, Simone; Meagher, Jonathan P.; Durden, Stephen L.; Im, Eastwood

    2004-01-01

    Following the successful Precipitation Radar (PR) of the Tropical Rainfall Measuring Mission, a new airborne, 14/35 GHz rain profiling radar, known as Airborne Precipitation Radar - 2 (APR-2), has been developed as a prototype for an advanced, dual-frequency spaceborne radar for a future spaceborne precipitation measurement mission. . This airborne instrument is capable of making simultaneous measurements of rainfall parameters, including co-pol and cross-pol rain reflectivities and vertical Doppler velocities, at 14 and 35 GHz. furthermore, it also features several advanced technologies for performance improvement, including real-time data processing, low-sidelobe dual-frequency pulse compression, and dual-frequency scanning antenna. Since August 2001, APR-2 has been deployed on the NASA P3 and DC8 aircrafts in four experiments including CAMEX-4 and the Wakasa Bay Experiment. Raw radar data are first processed to obtain reflectivity, LDR (linear depolarization ratio), and Doppler velocity measurements. The dataset is then processed iteratively to accurately estimate the true aircraft navigation parameters and to classify the surface return. These intermediate products are then used to refine reflectivity and LDR calibrations (by analyzing clear air ocean surface returns), and to correct Doppler measurements for the aircraft motion. Finally, the the melting layer of precipitation is detected and its boundaries and characteristics are identifIed at the APR-2 range resolution of 30m. The resulting 3D dataset will be used for validation of other airborne and spaceborne instruments, development of multiparametric rain/snow retrieval algorithms and melting layer characterization and statistics.

  16. AESMIR: A New NASA Airborne Microwave Imager

    NASA Technical Reports Server (NTRS)

    Kim, Edward J.; Hood, Robbie; Hildebrand, Peter H. (Technical Monitor)

    2001-01-01

    The Airborne Earth Science Microwave Imaging Radiometer (AESMIR) is a versatile new airborne imaging radiometer under development by NASA. The AESMIR design is unique in that it will perform dual-polarized imaging at all AMSR frequency bands (6.9 through 89 GHz) using only one sensor head/scanner package, providing an efficient solution for AMSR-type science applications (snow, soil moisture/land parameters, precip, ocean winds, SST, water vapor, sea ice, etc.). The microwave radiometers themselves will incorporate state-of-the-art receivers, with particular attention given to instrument calibration for the best possible accuracy and sensitivity. The single-package design of AESMIR makes it compatible with high-altitude aircraft platforms such as the NASA ER-2s and the Proteus. The arbitrary 2-axis gimbal can perform conical and cross-track scanning, as well as fixed-beam staring. This compatibility with high-altitude platforms coupled with the flexible scanning configuration, opens up previously unavailable science opportunities for convection/precip/cloud science and co-flying with complementary instruments, as well as providing wider swath coverage for all science applications. By designing AESMIR to be compatible with these high-altitude platforms, we are also compatible with the NASA P-3, the NASA DC-8, and ground-based deployments. Thus AESMIR can provide low-, mid-, and high altitude microwave imaging.

  17. Airborne Visible Laser Optical Communications Program (AVLOC)

    NASA Technical Reports Server (NTRS)

    Ward, J. H.

    1975-01-01

    The design, development, and operation of airborne and ground-based laser communications and laser radar hardware is described in support of the Airborne Visible Laser Optical Communication program. The major emphasis is placed on the development of a highly flexible test bed for the evaluation of laser communications systems techniques and components in an operational environment.

  18. The Continuous wavelet in airborne gravimetry

    NASA Astrophysics Data System (ADS)

    Liang, X.; Liu, L.

    2013-12-01

    Airborne gravimetry is an efficient method to recover medium and high frequency band of earth gravity over any region, especially inaccessible areas, which can measure gravity data with high accuracy,high resolution and broad range in a rapidly and economical way, and It will play an important role for geoid and geophysical exploration. Filtering methods for reducing high-frequency errors is critical to the success of airborne gravimetry due to Aircraft acceleration determination based on GPS.Tradiontal filters used in airborne gravimetry are FIR,IIR filer and so on. This study recommends an improved continuous wavelet to process airborne gravity data. Here we focus on how to construct the continuous wavelet filters and show their working principle. Particularly the technical parameters (window width parameter and scale parameter) of the filters are tested. Then the raw airborne gravity data from the first Chinese airborne gravimetry campaign are filtered using FIR-low pass filter and continuous wavelet filters to remove the noise. The comparison to reference data is performed to determinate external accuracy, which shows that continuous wavelet filters applied to airborne gravity in this thesis have good performances. The advantages of the continuous wavelet filters over digital filters are also introduced. The effectiveness of the continuous wavelet filters for airborne gravimetry is demonstrated through real data computation.

  19. A highly sensitive fiber Bragg grating diaphragm pressure transducer

    NASA Astrophysics Data System (ADS)

    Allwood, Gary; Wild, Graham; Lubansky, Alex; Hinckley, Steven

    2015-10-01

    In this work, a novel diaphragm based pressure transducer with high sensitivity is described, including the physical design structure, in-depth analysis of optical response to changes in pressure, and a discussion of practical implementation and limitations. A flat circular rubber membrane bonded to a cylinder forms the body of the transducer. A fiber Bragg grating bonded to the center of the diaphragm structure enables the fractional change in pressure to be determined by analyzing the change in Bragg wavelength of the reflected spectra. Extensive evaluation of the physical properties and optical characteristics of the transducer has been performed through experimentation, and modeling using small deformation theory. The results show the transducer has a sensitivity of 0.116 nm/kPa, across a range of 15 kPa. Ultra-low cost interrogation of the optical signal was achieved through the use of an optically mismatched Bragg grating acting as an edge filter to convert the spectral change into an intensity change. A numerical model of the intensity based interrogation was implemented in order to validate the experimental results. Utilizing this interrogation technique and housing both the sensing and reference Bragg gratings within the main body of the transducer means it is effectively temperature insensitive and easily connected to electronic systems.

  20. Kinetics of Highly Sensitive Troponin T after Cardiac Surgery

    PubMed Central

    Omar, Amr S.; Sudarsanan, Suraj; Hanoura, Samy; Osman, Hany; Sivadasan, Praveen C.; Shouman, Yasser; Tuli, Alejandro Kohn; Singh, Rajvir; Al Khulaifi, Abdulaziz

    2015-01-01

    Perioperative myocardial infarction (PMI) confers a considerable risk in cardiac surgery settings; finding the ideal biomarker seems to be an ideal goal. Our aim was to assess the diagnostic accuracy of highly sensitive troponin T (hsTnT) in cardiac surgery settings and to define a diagnostic level for PMI diagnosis. This was a single-center prospective observational study analyzing data from all patients who underwent cardiac surgeries. The primary outcome was the diagnosis of PMI through a specific level. The secondary outcome measures were the lengths of mechanical ventilation (LOV), stay in the intensive care unit (LOSICU), and hospitalization. Based on the third universal definition of PMI, patients were divided into two groups: no PMI (Group I) and PMI (Group II). Data from 413 patients were analyzed. Nine patients fulfilled the diagnostic criteria of PMI, while 41 patients were identified with a 5-fold increase in their CK-MB (≥120 U/L). Using ROC analysis, a hsTnT level of 3,466 ng/L or above showed 90% sensitivity and 90% specificity for the diagnosis of PMI. Secondary outcome measures in patients with PMI were significantly prolonged. In conclusion, the hsTnT levels detected here paralleled those of CK-MB and a cut-off level of 3466 ng/L could be diagnostic of PMI. PMID:26539512

  1. High sensitivity tracking of CD-SEM performance: QSEM

    NASA Astrophysics Data System (ADS)

    Babin, S.; Huang, Jaffee; Yushmanov, P.

    2015-03-01

    The performance of CD-SEMs directly affects the measured values of critical dimensions (CDs) at the time of their measurement. Tracking the performance of CD-SEMs is necessary to establish trust in their results and provide guidance for preventive maintenance and tune-ups. When the measured CDs are out of specification in manufacturing, it is crucial to determine whether this is due to process variation or the metrology tool itself. Multiple methods that use linewidth measurements have been employed thus far; however, they suffer from linewidth variations on the wafer, as well as from variations of line edge and linewidth roughness. Here, we report a method that is capable of providing a quantitative extraction of the SEM performance based on advanced algorithms. The method is independent of linewidth, line edge roughness and linewidth roughness, and has high sensitivity. This software, QSEM, was developed to automatically evaluate image quality and assign a value to that quality. The image quality value is based on multiple factors such as noise, sharpness, analysis of histograms, and contrast. The sensitivity of the software was evaluated; a good correlation between image quality results and linewidth variation due to SEM performance was established. Using QSEM to analyze SEM images allows the performance of CDSEMs to be tracked for proper calibration and preventive maintenance, as well as to resolve the dispute between failure in the process or the metrology.

  2. High-sensitivity quantitative phase microcopy (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Zhou, Renjie; Kuang, Cuifang; Hosseini, Poorya; Chowdhary, Ravi; Yaqoob, Zahid; So, Peter T. C.

    2016-03-01

    In the past decade, various quantitative phase microscopy (QPM) techniques have emerged, driven by the need to study biological samples non-invasively. However, the fundamental limit for phase noise is scarcely discussed in the literature. In a typically off-axis phase microscope system, the phase noise is limited to a few milliradians using a moderate camera. Common-path QPMs offer much reduced phase noise compared to typical Mach-Zehnder-based systems. However, further scaling down the phase noise becomes difficult. Here we propose a high-sensitivity common-path QPM that promises to reduce the phase noise by a factor of 10 (assuming the mechanical noise is negligible). This is achieved by a specifically designed signal filter, leaving only the subtle phase fluctuations coming from the dynamics sample scattering. By working at photon shot-noise limited detection, we can magnify the subtle phase contrast which is proportional to the camera well depth. We expect this system to have the height sensitivity similar to an atomic force microcopy, while measuring biological structures with a full field of view in a single-shot. We plan to use this system to study cell dynamics, particularly lamellipodial height fluctuations as well as stiffer cell membrane fluctuations.

  3. High sensitivity, low profile neutron detector for safeguards measurements

    SciTech Connect

    Miley, H.S.; Abraham, J.R.; Thompson, R.C.; Sunberg, D.S.

    1993-12-01

    A neutron detector has been constructed and tested at Pacific Northwest Laboratory (PNL) for the purpose of making fast, high sensitivity measurements of neutron emitters in portal applications. The system is based upon glass fiber optic scintillators loaded with lithium-6 and operated to detect thermal neutrons. Due to their compact size. physical flexibility, freedom from microphonic pickup, and complete lack of environmental and safety concerns, these fibers are very suitable for some applications. The electronics needed for these fibers is somewhat more complex than for helium-3 proportional counters, but the entire electronics package (including the controlling computer) has been shrunk into a space of 20 {times} 25 {times} 2 cm. The prototype sensor is about 180 {times} 60 {times} 7 cm, but a final design now under construction measures 200 {times} 28 {times} 2.54 cm. The new, smaller detectors will be capable of ganging to achieve any needed sensitivity and will each weigh about 16 kg. The principles of operation of the fiber will be discussed as will the operational mode of the detector.

  4. Luminescent Lanthanide Reporters for High-Sensitivity Novel Bioassays.

    SciTech Connect

    Anstey, Mitchell; Fruetel, Julia A.; Foster, Michael E.; Hayden, Carl C.; Buckley, Heather L.; Arnold, John

    2013-09-01

    Biological imaging and assay technologies rely on fluorescent organic dyes as reporters for a number of interesting targets and processes. However, limitations of organic dyes such as small Stokes shifts, spectral overlap of emission signals with native biological fluorescence background, and photobleaching have all inhibited the development of highly sensitive assays. To overcome the limitations of organic dyes for bioassays, we propose to develop lanthanide-based luminescent dyes and demonstrate them for molecular reporting applications. This relatively new family of dyes was selected for their attractive spectral and chemical properties. Luminescence is imparted by the lanthanide atom and allows for relatively simple chemical structures that can be tailored to the application. The photophysical properties offer unique features such as narrow and non-overlapping emission bands, long luminescent lifetimes, and long wavelength emission, which enable significant sensitivity improvements over organic dyes through spectral and temporal gating of the luminescent signal.Growth in this field has been hindered due to the necessary advanced synthetic chemistry techniques and access to experts in biological assay development. Our strategy for the development of a new lanthanide-based fluorescent reporter system is based on chelation of the lanthanide metal center using absorbing chromophores. Our first strategy involves %22Click%22 chemistry to develop 3-fold symmetric chelators and the other involves use of a new class of tetrapyrrole ligands called corroles. This two-pronged approach is geared towards the optimization of chromophores to enhance light output.

  5. Sensitivity of once-shocked, weathered high explosives

    SciTech Connect

    Williams, K.L.; Harris, B.W.

    1998-07-01

    Effects caused by stimulating once-shocked, weathered high explosives (OSW-HE) are investigated. The sensitivity of OSW-HE to mechanical stimuli was determined using standard industry tests. Some initial results are given. Pieces of OSW-HE were collected from active and inactive firing sites and from an area surrounding a drop tower at Los Alamos where skid and spigot tests were done. Samples evaluated were cast explosives or plastic bonded explosive (PBX) formulations containing cyclotrimethylenetrinitramine (RDX), cyclotetramethylene tetranitramine (HMX), 2,4,6-trinitrotoluene (TNT), mock or inert HE [tris(beta-chloroethyl)phosphate (CEF)], barium nitrate, cyanuric acid, talc, and Kel-F. Once-shocked, weathered LX-10 Livermore explosive [HMX/Viton A, (95/5 wt %)], PBX 9011 [HMX/Estane, (90/10 wt %)], PBX 9404 [HMX/nitrocellulose, tris(beta-chloroethyl) phosphate, (94/3/3 wt %)], Composition B or cyclotol (TNT/RDX explosives), and PBX 9007 (90% RDX, 9.1% styrene, 0.5% dioctyl phthalate, and 0.45 resin) were subjected to the hammer test, the drop-weight impact sensitivity test, differential thermal analysis (DTA), the spark test, the Henkin`s critical temperature test, and the flame test. Samples were subjected to remote, wet cutting and drilling; remote, liquid-nitrogen-cooled grinding and crushing; and scanning electron microscope (SEM) surface analyses for morphological changes.

  6. Nanoparticle-Structured Highly Sensitive and Anisotropic Gauge Sensors.

    PubMed

    Zhao, Wei; Luo, Jin; Shan, Shiyao; Lombardi, Jack P; Xu, Yvonne; Cartwright, Kelly; Lu, Susan; Poliks, Mark; Zhong, Chuan-Jian

    2015-09-16

    The ability to tune gauge factors in terms of magnitude and orientation is important for wearable and conformal electronics. Herein, a sensor device is described which is fabricated by assembling and printing molecularly linked thin films of gold nanoparticles on flexible microelectrodes with unusually high and anisotropic gauge factors. A sharp difference in gauge factors up to two to three orders of magnitude between bending perpendicular (B(⊥)) and parallel (B(||)) to the current flow directions is observed. The origin of the unusual high and anisotropic gauge factors is analyzed in terms of nanoparticle size, interparticle spacing, interparticle structure, and other parameters, and by considering the theoretical aspects of electron conduction mechanism and percolation pathway. A critical range of resistivity where a very small change in strain and the strain orientation is identified to impact the percolation pathway in a significant way, leading to the high and anisotropic gauge factors. The gauge anisotropy stems from molecular and nanoscale fine tuning of interparticle properties of molecularly linked nanoparticle assembly on flexible microelectrodes, which has important implication for the design of gauge sensors for highly sensitive detection of deformation in complex sensing environment or on complex curved surfaces such as wearable electronics and skin sensors. PMID:26037089

  7. A geomorphologist's dream come true: synoptic high resolution river bathymetry with the latest generation of airborne dual wavelength lidar

    NASA Astrophysics Data System (ADS)

    Lague, Dimitri; Launeau, Patrick; Michon, Cyril; Gouraud, Emmanuel; Juge, Cyril; Gentile, William; Hubert-Moy, Laurence; Crave, Alain

    2016-04-01

    Airborne, terrestrial lidar and Structure From Motion have dramatically changed our approach of geomorphology, from low density/precision data, to a wealth of data with a precision adequate to actually measure topographic change across multiple scales, and its relation to vegetation. Yet, an important limitation in the context of fluvial geomorphology has been the inability of these techniques to penetrate water due to the use of NIR laser wavelengths or to the complexity of accounting for water refraction in SFM. Coastal bathymetric systems using a green lidar can penetrate clear water up to 50 m but have a resolution too coarse and deployment costs that are prohibitive for fluvial research and management. After early prototypes of narrow aperture green lidar (e.g., EEARL NASA), major lidar manufacturer are now releasing dual wavelength laser system that offer water penetration consistent with shallow fluvial bathymetry at very high resolution (> 10 pts/m²) and deployment costs that makes the technology, finally accessible. This offers unique opportunities to obtain synoptic high resolution, high precision data for academic research as well as for fluvial environment management (flood risk mapping, navigability,…). In this presentation, we report on the deployment of the latest generation Teledyne-Optech Titan dual-wavelength lidar (1064 nm + 532 nm) owned by the University of Nantes and Rennes. The instrument has been deployed over several fluvial and lacustrine environments in France. We present results and recommendation on how to optimize the bathymetric cover as a function of aerial and aquatic vegetation cover and the hydrology regime of the river. In the surveyed rivers, the penetration depth varies from 0.5 to 4 m with discrete echoes (i.e., onboard detection), heavily impacted by water clarity and bottom reflectance. Simple post-processing of the full waveform record allows to recover an additional 20 % depth. As for other lidar techniques, the main

  8. Three years of practical use of airborne gravity gradiometry

    NASA Astrophysics Data System (ADS)

    van Leeuwen, E.

    2003-04-01

    BHP Billiton has successfully built and deployed three airborne gravity gradiometer (AGG) systems, (Newton, Einstein and Galileo) based upon the Bell Airspace (now Lockheed Martin) Gravity Gradient Instruments developed for the United States Department of Defense. A second-generation gradiometer (Feynman) is presently nearing completion. The GGI technology is based on groups of four (4) accelerometers where the accelerometers are equi-spaced on a circle. The configuration successfully rejects both common mode accelerations and rotations about the axis perpendicular to the plane of the complement. The GGI is mounted within an aircraft in a specially designed, inertially stabilized platform, which significantly reduces sensitivity to noise and turbulence. The BHP Billiton AGG Technology provides high quality gravity maps with a resolution and sensitivity to map gravity anomalies associated with both minerals and hydrocarbon deposits. To date the purpose built and designed hardware and data processing algorithms, in conjunction with several other geophysical survey instruments, have been deployed against a broad range of mineral and hydrocarbon targets, a total of over 300,000km of operational flights having been made. Data will also be presented on the in-flight sensitivity of a gravity gradiometer to the airborne environment. It will also outline some of the many unexpected problems that were encountered in the 18-month flight trials required to achieve satisfactory airborne operation.

  9. High-sensitivity dilatometer for quality-control use

    NASA Astrophysics Data System (ADS)

    Tomer, G. S.; Schlegel, G. L.; Gaal, P. S.

    1988-03-01

    A simple-to-operate dilatometer, intended for rapid quality-control testing of low-expansion materials in a single temperature interval, is described. The instrument employs a thermoelectric heat/cool element to supply the thermal environment for the sample and a high-sensitivity linear variable differential transformer (LVDT) for displacement measurement. The mechanical configuration is made so as to eliminate the need for quartz correction and to provide a 4∶1 mechanical advantage to the displacement signal for improved accuracy. Operating between 0 and 100°C, the machine proved to give consistently good results with materials having expansion coefficients as low as 0.5×10-6 °C-1. Representative data on some carbonaceous materials and fused silica (quartz) are given.

  10. Highly sensitive biological sensor based on photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Azzam, Shaimaa I. H.; Hameed, Mohamed F.; Obayya, S. S. A.

    2014-05-01

    A photonic crystal fiber (PCF) surface plasmon resonance (SPR) based sensor is proposed and analysed. The proposed sensor consists of microuidic slots enclosing a dodecagonal layer of air holes cladding and a central air hole. The sensor can perform analyte detection using both HEx 11 and HEy 11 modes with a relatively high sensitivities up to 4000 nm=RIU and 3000 nm=RIU and resolutions of 2.5×10-5 RIU-1 and 3.33×10-5 RIU-1 with HEx11 and HEy11, respectively, with regards to spectral interrogation which to our knowledge are higher than those reported in the literature. Moreover, the structure of the suggested sensor is simple with no fabrication complexities which makes it easy to fabricate with standard PCF fabrication technologies.

  11. Sensitivity of LHC experiments to exotic highly ionising particles

    NASA Astrophysics Data System (ADS)

    De Roeck, A.; Katre, A.; Mermod, P.; Milstead, D.; Sloan, T.

    2012-04-01

    The experiments at the Large Hadron Collider (LHC) are able to discover or set limits on the production of exotic particles with TeV-scale masses possessing values of electric and/or magnetic charge such that they behave as highly ionising particles (HIPs). In this paper the sensitivity of the LHC experiments to HIP production is discussed in detail. It is shown that a number of different detection methods are required to investigate as fully as possible the charge-mass range. These include direct detection as the HIPs pass through either passive or active detectors and, in the case of magnetically charged objects, the so-called induction method with which magnetic monopoles which stop in accelerator and detector material could be observed. The benefit of using complementary approaches to HIP detection is discussed.

  12. Versatile, high-sensitivity faraday cup array for ion implanters

    DOEpatents

    Musket, Ronald G.; Patterson, Robert G.

    2003-01-01

    An improved Faraday cup array for determining the dose of ions delivered to a substrate during ion implantation and for monitoring the uniformity of the dose delivered to the substrate. The improved Faraday cup array incorporates a variable size ion beam aperture by changing only an insertable plate that defines the aperture without changing the position of the Faraday cups which are positioned for the operation of the largest ion beam aperture. The design enables the dose sensitivity range, typically 10.sup.11 -10.sup.18 ions/cm.sup.2 to be extended to below 10.sup.6 ions/cm.sup.2. The insertable plate/aperture arrangement is structurally simple and enables scaling to aperture areas between <1 cm.sup.2 and >750 cm.sup.2, and enables ultra-high vacuum (UHV) applications by incorporation of UHV-compatible materials.

  13. Radiation noise in a high sensitivity star sensor

    NASA Technical Reports Server (NTRS)

    Parkinson, J. B.; Gordon, E.

    1972-01-01

    An extremely accurate attitude determination was developed for space applications. This system uses a high sensitivity star sensor in which the photomultiplier tube is subject to noise generated by space radiations. The space radiation induced noise arises from trapped electrons, solar protons and other ionizing radiations, as well as from dim star background. The solar activity and hence the electron and proton environments are predicted through the end of the twentieth century. The available data for the response of the phototube to proton, electron, gamma ray, and bremsstrahlung radiations are reviewed and new experimental data is presented. A simulation was developed which represents the characteristics of the effect of radiations on the star sensor, including the non-stationarity of the backgrounds.

  14. High-sensitivity broadband microwave spectroscopy with small nonresonant coils

    NASA Astrophysics Data System (ADS)

    Mahdjour, H.; Clark, W. G.; Baberschke, K.

    1986-06-01

    The use of a small, nonresonant, coil of micron dimensions as the microwave magnetic field structure of a broadband electron-spin-resonance (ESR) spectrometer is described. The coil is driven by a broadband microwave generator which operates between 0.1 and 8.5 GHz. The samples may fill the coil to approximately 100 percent. It is shown that for small size samples this system offers higher sensitivity than a conventional cavity spectrometer. Because the system is broadband, either frequency scans or the conventional magnetic field scans can be used to traverse the resonance. Examples for DPPH and for the spin glass AgMn using this method are reported. Since the sample coil is small, it has many potential applications, such as insertion into the mixing chamber of dilution refrigerator or high-pressure cell, efficient use of power in ENDOR and other double resonance experiments, and rapid recovery from transients in pulsed ESR experiments.

  15. Variation in airborne 137Cs peak levels with altitude from high-altitude locations across Europe after the arrival of Fukushima-labeled air masses

    NASA Astrophysics Data System (ADS)

    Masson, Olivier; Bieringer, Jacqueline; Dalheimer, Axel; Estier, Sybille; Evrard, Olivier; Penev, Ilia; Ringer, Wolfgang; Schlosser, Clemens; Steinkopff, Thomas; Tositti, Laura; de Vismes-Ott, Anne

    2015-04-01

    During the Fukushima Daiichi nuclear power plant (FDNPP) accident, a dozen of high-altitude aerosol sampling stations, located between 850 and 3,454 m above sea level (a.s.l.), provided airborne activity levels across Europe (Fig. 1). This represents at most 5% of the total number of aerosol sampling locations that delivered airborne activity levels (at least one result) in Europe, in connection with this nuclear accident. High altitude stations are typically equipped with a high volume sampler that collects aerosols on filters. The Fukushima-labeled air mass arrival and the peak of airborne cesium-137 (137Cs) activity levels were registered in Europe at different dates depending on the location, with differences up to a factor of six on a regional scale. Besides this statement related to lowland areas, we have compared the maximum airborne levels registered at high-altitude European locations (850 m < altitudes < 3450 m) with what was observed at the closest lowland location. The vertical distribution of 137Cs peak level was not uniform even after a long travel time/distance from Japan. This being true at least in the atmospheric boundary layer and in the lower free troposphere. Moreover the relation '137Csmax vs. altitude' shows a decreasing trend (Fig. 2). Results and discussion : Comparison of 137Cs and 7Be levels shows simultaneous increases at least when the 137Cs airborne level rose for the first time (Fig. 3). Zugspitze and Jungfraujoch stations attest of a time shift between 7Be and 137Cs peak that can be due to the particular dynamic of air movements at such high altitudes. After the 137Cs peak value, the plume concentration decreased whatever the 7Be level. Due to the cosmogenic origin of 7Be, its increase in the ground-level air is usually associated with downwind air movements, i.e. stratospheric air intrusions or at least air from high-tropospheric levels, into lower atmospheric layers. This means that Fukushima-labeled air masses registered at ground

  16. A Cryogenic, Insulating Suspension System for the High Resolution Airborne Wideband Camera (HAWC)and Submillemeter And Far Infrared Experiment (SAFIRE) Adiabatic Demagnetization Refrigerators (ADRs)

    NASA Technical Reports Server (NTRS)

    Voellmer, George M.; Jackson, Michael L.; Shirron, Peter J.; Tuttle, James G.

    2002-01-01

    The High Resolution Airborne Wideband Camera (HAWC) and the Submillimeter And Far Infrared Experiment (SAFIRE) will use identical Adiabatic Demagnetization Refrigerators (ADR) to cool their detectors to 200mK and 100mK, respectively. In order to minimize thermal loads on the salt pill, a Kevlar suspension system is used to hold it in place. An innovative, kinematic suspension system is presented. The suspension system is unique in that it consists of two parts that can be assembled and tensioned offline, and later bolted onto the salt pill.

  17. Low Virulence and Lack of Airborne Transmission of the Dutch Highly Pathogenic Avian Influenza Virus H5N8 in Ferrets

    PubMed Central

    van den Brand, Judith M. A.; Lexmond, Pascal; Bestebroer, Theo M.; Rimmelzwaan, Guus F.; Koopmans, Marion; Kuiken, Thijs; Fouchier, Ron A. M.

    2015-01-01

    Highly pathogenic avian influenza (HPAI) H5N8 viruses that emerged in poultry in East Asia spread to Europe and North America by late 2014. Here we show that the European HPAI H5N8 viruses differ from the Korean and Japanese HPAI H5N8 viruses by several amino acids and that a Dutch HPAI H5N8 virus had low virulence and was not transmitted via the airborne route in ferrets. The virus did not cross-react with sera raised against pre-pandemic H5 vaccine strains. This data is useful for public health risk assessments. PMID:26090682

  18. Retrieval of effective leaf area index (LAIe) and leaf area density (LAD) profile at individual tree level using high density multi-return airborne LiDAR

    NASA Astrophysics Data System (ADS)

    Lin, Yi; West, Geoff

    2016-08-01

    As an important canopy structure indicator, leaf area index (LAI) proved to be of considerable implications for forest ecosystem and ecological studies, and efficient techniques for accurate LAI acquisitions have long been highlighted. Airborne light detection and ranging (LiDAR), often termed as airborne laser scanning (ALS), once was extensively investigated for this task but showed limited performance due to its low sampling density. Now, ALS systems exhibit more competing capacities such as high density and multi-return sampling, and hence, people began to ask the questions like-"can ALS now work better on the task of LAI prediction?" As a re-examination, this study investigated the feasibility of LAI retrievals at the individual tree level based on high density and multi-return ALS, by directly considering the vertical distributions of laser points lying within each tree crown instead of by proposing feature variables such as quantiles involving laser point distribution modes at the plot level. The examination was operated in the case of four tree species (i.e. Picea abies, Pinus sylvestris, Populus tremula and Quercus robur) in a mixed forest, with their LAI-related reference data collected by using static terrestrial laser scanning (TLS). In light of the differences between ALS- and TLS-based LAI characterizations, the methods of voxelization of 3D scattered laser points, effective LAI (LAIe) that does not distinguish branches from canopies and unified cumulative LAI (ucLAI) that is often used to characterize the vertical profiles of crown leaf area densities (LADs) was used; then, the relationships between the ALS- and TLS-derived LAIes were determined, and so did ucLAIs. Tests indicated that the tree-level LAIes for the four tree species can be estimated based on the used airborne LiDAR (R2 = 0.07, 0.26, 0.43 and 0.21, respectively) and their ucLAIs can also be derived. Overall, this study has validated the usage of the contemporary high density multi

  19. A13K-0336: Airborne Multi-Wavelength High Spectral Resolution Lidar for Process Studies and Assessment of Future Satellite Remote Sensing Concepts

    NASA Technical Reports Server (NTRS)

    Hostetler, Chris A.; Ferrare, Rich A.; Hair, Johnathan W.; Cook, Anthony L.; Harper, David B.; Mack, Terry L.; Hare, Richard J.; Cleckner, Craig S.; Rogers, Raymond R.; Muller, Detlef; Chemyakin, Eduard; Burton, Sharon P.; Obland, Michael D.; Scarino, Amy J.; Cairns, Brian; Russell, Phil; Redermann, Jens; Shinozuka, Y.; Schmid, Beat; Fast, Jerome; Berg, Larry; Flynn, Connor; Wagener, Rick; Gregory, Laurie

    2012-01-01

    NASA Langley recently developed the world's first airborne multi-wavelength high spectral resolution lidar (HSRL). This lidar employs the HSRL technique at 355 and 532 nm to make independent, unambiguous retrievals of aerosol extinction and backscatter. It also employs the standard backscatter technique at 1064 nm and is polarization-sensitive at all three wavelengths. This instrument, dubbed HSRL-2 (the secondgeneration HSRL developed by NASA Langley), is a prototype for the lidar on NASA's planned Aerosols- Clouds-Ecosystems (ACE) mission. HSRL-2 completed its first science mission in July 2012, the Two-Column Aerosol Project (TCAP) conducted by the Department of Energy (DOE) in Hyannis, MA. TCAP presents an excellent opportunity to assess some of the remote sensing concepts planned for ACE: HSRL-2 was deployed on the Langley King Air aircraft with another ACE-relevant instrument, the NASA GISS Research Scanning Polarimeter (RSP), and flights were closely coordinated with the DOE's Gulfstream-1 aircraft, which deployed a variety of in situ aerosol and trace gas instruments and the new Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR). The DOE also deployed their Atmospheric Radiation Measurement Mobile Facility and their Mobile Aerosol Observing System at a ground site located on the northeastern coast of Cape Cod for this mission. In this presentation we focus on the capabilities, data products, and applications of the new HSRL-2 instrument. Data products include aerosol extinction, backscatter, depolarization, and optical depth; aerosol type identification; mixed layer depth; and rangeresolved aerosol microphysical parameters (e.g., effective radius, index of refraction, single scatter albedo, and concentration). Applications include radiative closure studies, studies of aerosol direct and indirect effects, investigations of aerosol-cloud interactions, assessment of chemical transport models, air quality studies, present (e.g., CALIPSO

  20. Domestic Mite Antigens in Floor and Airborne Dust at Workplaces in Comparison to Living Areas: A New Immunoassay to Assess Personal Airborne Allergen Exposure

    PubMed Central

    Sander, Ingrid; Zahradnik, Eva; Kraus, Gerhard; Mayer, Stefan; Neumann, Heinz-Dieter; Fleischer, Christina; Brüning, Thomas; Raulf-Heimsoth, Monika

    2012-01-01

    Objectives Allergens produced by domestic mites (DM) are among the most common allergic sensitizers and risk factors for asthma. To compare exposure levels between workplaces and living areas a new assay able to measure airborne DM antigen concentrations was developed. Methods At workplaces and in living areas, 213 floor dust samples and 92 personal inhalable dust samples were collected. For sensitive quantification of DM antigens, a new enzyme immunoassay (EIA) based on polyclonal antibodies to Dermatophagoides farinae extract was developed. Reactivity of five house dust mite and four storage mite species was tested. All dust samples were tested with the new EIA and with the Der f 1 and Der p 1-EIAs (Indoor Biotechnologies, UK) which detect major allergens from D. farinae and D. pteronyssinus by monoclonal antibodies. Samples below the detection limit in the DM-EIA were retested in an assay variant with a fluorogenic substrate (DM-FEIA). Results The newly developed DM-EIA detects antigens from all nine tested domestic mite species. It has a lower detection limit of 200 pg/ml of D.farinae protein, compared to 50 pg/ml for the DM-FEIA. DM antigens were detected by DM-EIA/FEIA in all floor dust and 80 (87%) of airborne samples. Der f 1 was found in 133 (62%) floor dust and in only 6 airborne samples, Der p 1 was found in 70 (33%) of floor samples and in one airborne sample. Der f 1 and DM concentrations were highly correlated. DM-antigens were significantly higher in inhalable airborne samples from textile recycling, bed feather filling, feed production, grain storage and cattle stables in comparison to living areas. Conclusions A new sensitive EIA directed at DM antigens was developed. DM antigen quantities were well correlated to Der f 1 values and were measurable in the majority (87%) of airborne dust samples. Some workplaces had significantly higher DM antigen concentrations than living areas. PMID:23285240

  1. High-sensitivity and high-dry-etching durability positive-type electron-beam resist

    NASA Astrophysics Data System (ADS)

    Tamura, Akira; Yonezawa, Masaji; Sato, Mitsuyoshi; Fujimoto, Yoshiaki

    1991-08-01

    As feature sizes of semiconductors grow smaller, a resist having dry etching durability and high sensitivity is required for electron beam lithography. However, the positive type electron beam resist having both high sensitivity and high dry etching durability, which suits for practical use, has not been developed yet. In order to solve this problem, a homologous series of poly(alkyl 2-cyanoacrylate) has been investigated. As a result, the new positive type electron beam resist having high sensitivity, high dry etching durability, and high thermal resistance has been developed. This new type of resist consists of poly(cyclohexyl 2- cyanoacrylate), and these features of this resist are due to the cyano and the cyclohexyl groups. The dry etching durability of this resist is 2.19 times as high as that of poly(mthyl methacrylate) (PMMA). The sensitivity is 1.7 (mu) C/cm2 at accelerating voltage of 20 kV, which is about the same as that of poly(butene-1-sulfone) (PBS). Moreover, poly(cyclohexyl 2-cyanoacrylate) has the glass transition of 152 degree(s)C, and then it is thermally stable. Using this resist in photomask fabrication by dry etching, the chrome linewidth uniformity of 0.034 micrometers 3 (sigma) can be obtained.

  2. High-sensitivity detection of trace gases using dynamic photoacoustic spectroscopy

    NASA Astrophysics Data System (ADS)

    Wynn, Charles M.; Palmacci, Stephen; Clark, Michelle L.; Kunz, Roderick R.

    2014-02-01

    Lincoln Laboratory of Massachusetts Institute of Technology has developed a technique known as dynamic photoacoustic spectroscopy (DPAS) that could enable remote detection of trace gases via a field-portable laser-based system. A fielded DPAS system has the potential to enable rapid, early warning of airborne chemical threats. DPAS is a new form of photoacoustic spectroscopy that relies on a laser beam swept at the speed of sound to amplify an otherwise weak photoacoustic signal. We experimentally determine the sensitivity of this technique using trace quantities of SF6 gas. A clutter-limited sensitivity of ˜100 ppt is estimated for an integration path of 0.43 m. Additionally, detection at ranges over 5 m using two different detection modalities is demonstrated: a parabolic microphone and a laser vibrometer. Its utility in detecting ammonia emanating from solid samples in an ambient environment is also demonstrated.

  3. Innovative nanostructures for highly sensitive vibrational biosensing (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Popp, Juergen; Mayerhöfer, Thomas; Cialla-May, Dana; Weber, Karina; Huebner, Uwe

    2016-03-01

    Employing vibrational spectroscopy (IR-absorption and Raman spectroscopy) allows for the labelfree detection of molecular specific fingerprints of inorganic, organic and biological substances. The sensitivity of vibrational spectroscopy can be improved by several orders of magnitude via the application of plasmonic active surfaces. Within this contribution we will discuss two such approaches, namely surface enhanced Raman spectroscopy (SERS) as well as surface enhanced IR absorption (SEIRA). It will be shown that SERS using metal colloids as SERS active substrate in combination with a microfluidic lab-on-a-chip (LOC) device enables high throughput and reproducible measurements with highest sensitivity and specificity. The application of such a LOC-SERS approach for therapeutic drug monitoring (e.g. quantitative detection of antibiotics in a urine matrix) will be presented. Furthermore, we will introduce innovative bottom-up strategies to prepare SERS-active nanostructures coated with a lipophilic sensor layer as one-time use SERS substrates for specific food analysis (e.g. quantitative detection of toxic food colorants). The second part of this contribution presents a slit array metamaterial perfect absorber for IR sensing applications consisting of a dielectric layer sandwiched between two metallic layers of which the upper layer is perforated with a periodic array of slits. Light-matter interaction is greatly amplified in the slits, where also the analyte is concentrated, as the surface of the substrate is covered by a thin silica layer. Thus, already small concentrations of analytes down to a monolayer can be detected by refractive index sensing and identified by their spectral fingerprints with a standard mid-infrared lab spectrometer.

  4. Graphene nanomesh as highly sensitive chemiresistor gas sensor.

    PubMed

    Paul, Rajat Kanti; Badhulika, Sushmee; Saucedo, Nuvia M; Mulchandani, Ashok

    2012-10-01

    Graphene is a one atom thick carbon allotrope with all surface atoms that has attracted significant attention as a promising material as the conduction channel of a field-effect transistor and chemical field-effect transistor sensors. However, the zero bandgap of semimetal graphene still limits its application for these devices. In this work, ethanol-chemical vapor deposition (CVD) of a grown p-type semiconducting large-area monolayer graphene film was patterned into a nanomesh by the combination of nanosphere lithography and reactive ion etching and evaluated as a field-effect transistor and chemiresistor gas sensors. The resulting neck-width of the synthesized nanomesh was about ∼20 nm and was comprised of the gap between polystyrene (PS) spheres that was formed during the reactive ion etching (RIE) process. The neck-width and the periodicities of the graphene nanomesh (GNM) could be easily controlled depending on the duration/power of the RIE and the size of the PS nanospheres. The fabricated GNM transistor device exhibited promising electronic properties featuring a high drive current and an I(ON)/I(OFF) ratio of about 6, significantly higher than its film counterpart. Similarly, when applied as a chemiresistor gas sensor at room temperature, the graphene nanomesh sensor showed excellent sensitivity toward NO(2) and NH(3), significantly higher than their film counterparts. The ethanol-based graphene nanomesh sensors exhibited sensitivities of about 4.32%/ppm in NO(2) and 0.71%/ppm in NH(3) with limits of detection of 15 and 160 ppb, respectively. Our demonstrated studies on controlling the neck width of the nanomesh would lead to further improvement of graphene-based transistors and sensors. PMID:22931286

  5. Graphene nanomesh as highly sensitive chemiresistor gas sensor

    PubMed Central

    Paul, Rajat Kanti; Badhulika, Sushmee; Saucedo, Nuvia M.; Mulchandani, Ashok

    2016-01-01

    Graphene is a one atom thick carbon allotrope with all surface atoms that has attracted significant attention as a promising material as the conduction channel of a field-effect transistor and chemical field-effect transistor sensors. However, the zero bandgap of semimetal graphene still limits its application for these devices. In this work, ethanol-chemical vapor deposition (CVD) grown p-type semiconducting large-area monolayer graphene film was patterned into nanomesh by the combination of nanosphere lithography and reactive ion etching and evaluated as field-effect transistor and chemiresistor gas sensors. The resulting neck-width of the synthesized nanomesh was about ~20 nm comprised of the gap between polystyrene spheres that was formed during the reactive ion etching process. The neck-width and the periodicities of the graphene nanomesh could be easily controlled depending the duration/power of RIE and the size of PS nanospheres. The fabricated GNM transistor device exhibited promising electronic properties featuring high drive current and ION/IOFF ratio of about 6, significantly higher than its film counterpart. Similarly, when applied as chemiresistor gas sensor at room temperature, the graphene nanomesh sensor showed excellent sensitivity towards NO2 and NH3, significantly higher than their film counterparts. The ethanol-based graphene nanomesh sensors exhibited sensitivities of about 4.32%/ppm in NO2 and 0.71%/ppm in NH3 with limit of detections of 15 ppb and 160 ppb, respectively. Our demonstrated studies on controlling the neck width of the nanomesh would lead to further improvement of graphene-based transistors and sensors. PMID:22931286

  6. Wide bandwidth transimpedance amplifier for extremely high sensitivity continuous measurements.

    PubMed

    Ferrari, Giorgio; Sampietro, Marco

    2007-09-01

    This article presents a wide bandwidth transimpedance amplifier based on the series of an integrator and a differentiator stage, having an additional feedback loop to discharge the standing current from the device under test (DUT) to ensure an unlimited measuring time opportunity when compared to switched discharge configurations while maintaining a large signal amplification over the full bandwidth. The amplifier shows a flat response from 0.6 Hz to 1.4 MHz, the capability to operate with leakage currents from the DUT as high as tens of nanoamperes, and rail-to-rail dynamic range for sinusoidal current signals independent of the DUT leakage current. Also available is a monitor output of the stationary current to track experimental slow drifts. The circuit is ideal for noise spectral and impedance measurements of nanodevices and biomolecules when in the presence of a physiological medium and in all cases where high sensitivity current measurements are requested such as in scanning probe microscopy systems. PMID:17902966

  7. High olfactory sensitivity for dimethyl sulphide in harbour seals

    PubMed Central

    Kowalewsky, Sylvia; Dambach, Martin; Mauck, Björn; Dehnhardt, Guido

    2005-01-01

    Productive areas are patchily distributed at sea and represent important feeding grounds for many marine organisms. Although pinnipeds are known to travel on direct routes and return regularly to particular feeding sites, the environmental information seals use to perform this navigation is as yet unknown. As atmospheric dimethyl sulphide (DMS) has been demonstrated to be a reliable indicator for profitable foraging areas, we tested seals for their ability to smell DMS at concentrations typical for the marine environment. Using a go/no-go response paradigm we determined the DMS detection threshold in two harbour seals (Phoca vitulina vitulina). DMS stimuli from 8.05×108 to 8 pmol (DMS) m−3(air) were tested against a control stimulus using a custom-made olfactometer. DMS-thresholds determined for both seals (20 and 13 pmol m−3) indicate that seals can detect ambient concentrations associated with high primary productivity, e.g. in the North Atlantic. Thus, seals possess an extraordinarily high olfactory sensitivity for DMS, which could provide a sensory basis for identifying or orienting to profitable foraging grounds. PMID:17148339

  8. High-sensitivity thermoluminescence applied to environmental monitoring

    NASA Astrophysics Data System (ADS)

    Velbeck, K. J.; Zhang, L.; Rotunda, Joe E.; Moscovitch, Marko

    1999-02-01

    We describe the development of a new environmental TLD Dosemeter Badge and dose computation algorithm based on the new LiF:Mg,Cu,P material. LiF:Mg,Cu,P, with its high sensitivity, tissue equivalence, energy independence, and low fading characteristics, is a natural choice for environmental dosimetry. The badge consists of a card and a plastic holder. The card contains four LiF:Mg,Cu,P elements, each 3.2 mm square and 0.4 mm thick, encapsulated in TeflonR. The badge is symmetrical and uses four filters to discriminate low and high energy photons and to determine Directional Dose Equivalent, H'(0.07,(alpha) ), and Ambient Dose Equivalent, H*(10). Extensive data was taken based on irradiations of 920 dosemeters to both single and mixed fields of photons and betas. In addition, angular incidence data of various fields was taken. The approach to the algorithm is empirical and is based on this data. While most algorithms are based solely on perpendicular incidence exposure, this algorithm is being developed to account for the angular response of the dosemeter. This paper will present the algorithm for perpendicular irradiation; the angular response portion is in development. The dosemeter is designed to meet the criteria of the new draft standard ANSI N13.29, 'Environmental Dosimetry Performance -- Criteria for Testing.'

  9. High sensitivity, low power, microfabricated electrochemical sensor for CO

    SciTech Connect

    Neuzil, P.; Kayvani, D.; Maclay, G.J.

    1996-12-31

    CO is a toxic byproduct of incomplete combustion. Improperly vented fireplaces and faulty furnaces cause a estimated 400 deaths in the US each year. The presence of high CO levels may also indicate the presence of a fire. Hence, improved CO detection is of great interest and in the last several years commercial CO detectors have been released. The two most common methods of CO detection in commercial systems for residential use are (1) optical colorometric method, and (2) tin oxide sensor. The colorometric method has the advantage of low power, but the devices tend to give an alarm condition when exposed to low CO levels for a long time period, are difficult to reset, and have a lifetime of about 1 year. The tin oxide sensors have limited stability and high power requirement since the sensor must be heated. There is a need for a stable, sensitive, low power, low cost CO sensor. The authors have developed a planar amperometric sensor for CO detection using microfabrication technology.

  10. A batteryless temperature sensor based on high temperature sensitive material

    NASA Astrophysics Data System (ADS)

    Bakkali, Asma; Pelegri-Sebastia, José; Laghmich, Youssef; Lyhyaoui, Abdelouahid

    2016-05-01

    The major challenge in wireless sensor networks is the reduction of energy consumption. Passive wireless sensor network is an attractive solution for measuring physical parameters in harsh environment for large range of applications requiring sensing devices with low cost of fabrication, small size and long term measurement stability. Batteryless temperature sensing techniques are an active research field. The approach developed in our work holds a promising future for temperature sensor applications in order to successfully reduce the energy consumption. The temperature sensor presented in this paper is based on the electromagnetic transduction principle using the integration of the high temperature sensitive material into a passive structure. Variation in temperature makes the dielectric constant of this material changing, and such modification induces variation in the resonant frequencies of high-Q whispering-gallery modes (WGM) in the millimeter-wave frequency range. Following the results achieved, the proposed device shows a linear response to the increasing temperature and these variations can be remotely detected from a radar interrogation. Contribution to the topical issue "Materials for Energy Harvesting, Conversion and Storage (ICOME 2015) - Elected submissions", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

  11. High sensitivity dynamic spectral search for flare star radio

    NASA Technical Reports Server (NTRS)

    Abada-Simon, M.; Lecacheux, A.; Louarn, P.; Dulk, G. A.; Belkora, L.; Bookbinder, J. A.; Rosolen, C.

    1994-01-01

    We observed ten well-known flare stars with the Arcibo radio telescope at 1.4 GHz and 5 GHz, using a special observing technique to discriminate between real flares and radio freqeuncy interference. With a high sensitivity of 5.5 K/Jy at 1.4 GHz when averaged over a 50 MHz band, we are able to recognize flux enhancements as weak as approximately 6 mJy above the sky background variations. In about 85 hours of observation, about a dozen bursts were detected, only from AD Leo. All had flux densities lower than 70 mJy, which probably explains their lack of fine structures (except for the strongest one), such as were reported in the literature for stronger flares. Half of the bursts that we recorded are 100% circularly polarized, and half are not circularly polarized. Our results are a first attempt of reliable statistics on dMe flare rates at 1.4 GHz. The high brightness temperatures we infer for the observed bursts are interpreted in terms of coherent emission processes, either the cyclotron maser instability or plasma radiation. Efficiencies are comparable to those of solar or planetary radio emissions in the case of the cyclotron maser, and higher than the solar efficiency in the case of plasma radiation, with the caveat that there are great uncertainties in the coronal model and the source size.

  12. Accelerated Sensitivity Analysis in High-Dimensional Stochastic Reaction Networks

    PubMed Central

    Arampatzis, Georgios; Katsoulakis, Markos A.; Pantazis, Yannis

    2015-01-01

    Existing sensitivity analysis approaches are not able to handle efficiently stochastic reaction networks with a large number of parameters and species, which are typical in the modeling and simulation of complex biochemical phenomena. In this paper, a two-step strategy for parametric sensitivity analysis for such systems is proposed, exploiting advantages and synergies between two recently proposed sensitivity analysis methodologies for stochastic dynamics. The first method performs sensitivity analysis of the stochastic dynamics by means of the Fisher Information Matrix on the underlying distribution of the trajectories; the second method is a reduced-variance, finite-difference, gradient-type sensitivity approach relying on stochastic coupling techniques for variance reduction. Here we demonstrate that these two methods can be combined and deployed together by means of a new sensitivity bound which incorporates the variance of the quantity of interest as well as the Fisher Information Matrix estimated from the first method. The first step of the proposed strategy labels sensitivities using the bound and screens out the insensitive parameters in a controlled manner. In the second step of the proposed strategy, a finite-difference method is applied only for the sensitivity estimation of the (potentially) sensitive parameters that have not been screened out in the first step. Results on an epidermal growth factor network with fifty parameters and on a protein homeostasis with eighty parameters demonstrate that the proposed strategy is able to quickly discover and discard the insensitive parameters and in the remaining potentially sensitive parameters it accurately estimates the sensitivities. The new sensitivity strategy can be several times faster than current state-of-the-art approaches that test all parameters, especially in “sloppy” systems. In particular, the computational acceleration is quantified by the ratio between the total number of parameters over

  13. High Sensitive Precise 3D Accelerometer for Solar System Exploration with Unmanned Spacecrafts

    NASA Astrophysics Data System (ADS)

    Savenko, Y. V.; Demyanenko, P. O.; Zinkovskiy, Y. F.

    Solutions of several space and geophysical tasks require creating high sensitive precise accelerometers with sensitivity in order of 10 -13 g. These several tasks are following: inertial navigation of the Earth and Space; gravimetry nearby the Earth and into Space; geology; geophysics; seismology etc. Accelerometers (gravimeters and gradientmeters) with required sensitivity are not available now. The best accelerometers in the world have sensitivity worth on 4-5 orders. It has been developed a new class of fiber-optical sensors (FOS) with light pulse modulation. These sensors have super high threshold sensitivity and wide (up to 10 orders) dynamic range, and can be used as a base for creating of measurement units of physical values as 3D superhigh sensitive precise accelerometers of linear accelerations that is suitable for highest requirements. The principle of operation of the FOS is organically combined with a digital signal processing. It allows decreasing hardware of the accelerometer due to using a usual air-borne or space-borne computer; correcting the influence of natural, design, technological drawbacks of FOS on measured results; neutralising the influence of extraordinary situations available during using of FOS; decreasing the influence of internal and external destabilising factors (as for FOS), such as oscillation of environment temperature, instability of pendulum cycle frequency of sensitive element of the accelerometer etc. We were conducted a quantitative estimation of precise opportunities of analogue FOS in structure of fiber optical measuring devices (FOMD) for elementary FOMD with analogue FOS built on modern element basis of fiber optics (FO), at following assumptions: absolute parameter stability of devices of FOS measuring path; single transmission band of registration path; maximum possible inserted in optical fiber (OF) a radiated power. Even at such idealized assumptions, a calculated value in limit reached minimum inaccuracy of

  14. A highly sensitive technique for detecting catalytically active nanoparticles against a background of general workplace aerosols

    NASA Astrophysics Data System (ADS)

    Neubauer, N.; Weis, F.; Binder, A.; Seipenbusch, M.; Kasper, G.

    2011-07-01

    A new measurement technique was studied using catalysis to specifically detect airborne nanoparticles in presence of background particles in the workplace air. Catalytically active nanoparticles produced by spark discharge were used as aerosol catalysts. According to these particles suitable catalytic test reactions were chosen and investigated by two different approaches: catalysis on airborne nanoparticles and catalysis on deposited nanoparticles. The results indicate that catalysis is applicable for the specific measurement of nanoparticles in the workplace air. Catalysis on airborne particles is suitable for the specific detection of very active nanoparticles, e.g. platinum or nickel, at high concentrations of about 107 #/cm3. The approach of catalysis on deposited particles is better suited for nanoparticle aerosols at low concentrations, for slow catalytic reactions or less active nanoparticles like iron oxide (Fe2O3). On the basis of the experimental results detection limits in the range of μg or even ng were calculated which assure the good potential of catalysis for the specific detection of nanoparticles in the workplace air based on their catalytic activity.

  15. Highly sensitive and multiplexed platforms for allergy diagnostics

    NASA Astrophysics Data System (ADS)

    Monroe, Margo R.

    Allergy is a disorder of the immune system caused by an immune response to otherwise harmless environmental allergens. Currently 20% of the US population is allergic and 90% of pediatric patients and 60% of adult patients with asthma have allergies. These percentages have increased by 18.5% in the past decade, with predicted similar trends for the future. Here we design sensitive, multiplexed platforms to detect allergen-specific IgE using the Interferometric Reflectance Imaging Sensor (IRIS) for various clinical settings. A microarray platform for allergy diagnosis allows for testing of specific IgE sensitivity to a multitude of allergens, while requiring only small volumes of patient blood sample. However, conventional fluorescent microarray technology is limited by i) the variation of probe immobilization, which hinders the ability to make quantitative, assertive, and statistically relevant conclusions necessary in immunodiagnostics and ii) the use of fluorophore labels, which is not suitable for some clinical applications due to the tendency of fluorophores to stick to blood particulates and require daily calibration methods. This calibrated fluorescence enhancement (CaFE) method integrates the low magnification modality of IRIS with enhanced fluorescence sensing in order to directly correlate immobilized probe (major allergens) density to allergen-specific IgE in patient serum. However, this platform only operates in processed serum samples, which is not ideal for point of care testing. Thus, a high magnification modality of IRIS was adapted as an alternative allergy diagnostic platform to automatically discriminate and size single nanoparticles bound to specific IgE in unprocessed, characterized human blood and serum samples. These features make IRIS an ideal candidate for clinical and diagnostic applications, such a POC testing. The high magnification (nanoparticle counting) modality in conjunction with low magnification of IRIS in a combined instrument

  16. Evolution of a highly dilatant fault zone in the grabens of Canyonlands National Park, Utah, USA - integrating fieldwork, ground-penetrating radar and airborne imagery analysis

    NASA Astrophysics Data System (ADS)

    Kettermann, M.; Grützner, C.; van Gent, H. W.; Urai, J. L.; Reicherter, K.; Mertens, J.

    2015-07-01

    The grabens of Canyonlands National Park are a young and active system of sub-parallel, arcuate grabens, whose evolution is the result of salt movement in the subsurface and a slight regional tilt of the faulted strata. We present results of ground-penetrating radar (GPR) surveys in combination with field observations and analysis of high-resolution airborne imagery. GPR data show intense faulting of the Quaternary sediments at the flat graben floors, implying a more complex fault structure than visible at the surface. Direct measurements of heave and throw at several locations to infer fault dips at depth, combined with observations of primary joint surfaces in the upper 100 m, suggest a highly dilatant fault geometry. Sinkholes observed in the field as well as in airborne imagery give insights in local dilatancy and show where water and sediments are transported underground. Based on correlations of paleosols observed in outcrops and GPR profiles, we argue that either the grabens in Canyonlands National Park are older than previously assumed or that sedimentation rates were much higher in the Pleistocene.

  17. Nanoscale characterization of PM2.5 airborne pollutants reveals high adhesiveness and aggregation capability of soot particles

    PubMed Central

    Shi, Yuanyuan; Ji, Yanfeng; Sun, Hui; Hui, Fei; Hu, Jianchen; Wu, Yaxi; Fang, Jianlong; Lin, Hao; Wang, Jianxiang; Duan, Huiling; Lanza, Mario

    2015-01-01

    In 2012 air pollutants were responsible of seven million human death worldwide, and among them particulate matter with an aerodynamic diameter of 2.5 micrometers or less (PM2.5) are the most hazardous because they are small enough to invade even the smallest airways and penetrate to the lungs. During the last decade the size, shape, composition, sources and effect of these particles on human health have been studied. However, the noxiousness of these particles not only relies on their chemical toxicity, but particle morphology and mechanical properties affect their thermodynamic behavior, which has notable impact on their biological activity. Therefore, correlating the physical, mechanical and chemical properties of PM2.5 airborne pollutants should be the first step to characterize their interaction with other bodies but, unfortunately, such analysis has never been reported before. In this work, we present the first nanomechanical characterization of the most abundant and universal groups of PM2.5 airborne pollutants and, by means of atomic force microscope (AFM) combined with other characterization tools, we observe that fluffy soot aggregates are the most sticky and unstable. Our experiments demonstrate that such particles show strong adhesiveness and aggregation, leading to a more diverse composition and compiling all possible toxic chemicals. PMID:26177695

  18. Nanoscale characterization of PM2.5 airborne pollutants reveals high adhesiveness and aggregation capability of soot particles.

    PubMed

    Shi, Yuanyuan; Ji, Yanfeng; Sun, Hui; Hui, Fei; Hu, Jianchen; Wu, Yaxi; Fang, Jianlong; Lin, Hao; Wang, Jianxiang; Duan, Huiling; Lanza, Mario

    2015-01-01

    In 2012 air pollutants were responsible of seven million human death worldwide, and among them particulate matter with an aerodynamic diameter of 2.5 micrometers or less (PM2.5) are the most hazardous because they are small enough to invade even the smallest airways and penetrate to the lungs. During the last decade the size, shape, composition, sources and effect of these particles on human health have been studied. However, the noxiousness of these particles not only relies on their chemical toxicity, but particle morphology and mechanical properties affect their thermodynamic behavior, which has notable impact on their biological activity. Therefore, correlating the physical, mechanical and chemical properties of PM2.5 airborne pollutants should be the first step to characterize their interaction with other bodies but, unfortunately, such analysis has never been reported before. In this work, we present the first nanomechanical characterization of the most abundant and universal groups of PM2.5 airborne pollutants and, by means of atomic force microscope (AFM) combined with other characterization tools, we observe that fluffy soot aggregates are the most sticky and unstable. Our experiments demonstrate that such particles show strong adhesiveness and aggregation, leading to a more diverse composition and compiling all possible toxic chemicals. PMID:26177695

  19. Nanoscale characterization of PM2.5 airborne pollutants reveals high adhesiveness and aggregation capability of soot particles

    NASA Astrophysics Data System (ADS)

    Shi, Yuanyuan; Ji, Yanfeng; Sun, Hui; Hui, Fei; Hu, Jianchen; Wu, Yaxi; Fang, Jianlong; Lin, Hao; Wang, Jianxiang; Duan, Huiling; Lanza, Mario

    2015-07-01

    In 2012 air pollutants were responsible of seven million human death worldwide, and among them particulate matter with an aerodynamic diameter of 2.5 micrometers or less (PM2.5) are the most hazardous because they are small enough to invade even the smallest airways and penetrate to the lungs. During the last decade the size, shape, composition, sources and effect of these particles on human health have been studied. However, the noxiousness of these particles not only relies on their chemical toxicity, but particle morphology and mechanical properties affect their thermodynamic behavior, which has notable impact on their biological activity. Therefore, correlating the physical, mechanical and chemical properties of PM2.5 airborne pollutants should be the first step to characterize their interaction with other bodies but, unfortunately, such analysis has never been reported before. In this work, we present the first nanomechanical characterization of the most abundant and universal groups of PM2.5 airborne pollutants and, by means of atomic force microscope (AFM) combined with other characterization tools, we observe that fluffy soot aggregates are the most sticky and unstable. Our experiments demonstrate that such particles show strong adhesiveness and aggregation, leading to a more diverse composition and compiling all possible toxic chemicals.

  20. TRMM Precipitation Radar Reflectivity Profiles Compared to High-Resolution Airborne and Ground-Based Radar Measurements

    NASA Technical Reports Server (NTRS)

    Heymsfield, G. M.; Geerts, B.; Tian, L.

    1999-01-01

    In this paper, TRMM (Tropical Rainfall Measuring Mission Satellite) Precipitation Radar (PR) products are evaluated by means of simultaneous comparisons with data from the high-altitude ER-2 Doppler Radar (EDOP), as well as ground-based radars. The comparison is aimed primarily at the vertical reflectivity structure, which is of key importance in TRMM rain type classification and latent heating estimation. The radars used in this study have considerably different viewing geometries and resolutions, demanding non-trivial mapping procedures in common earth-relative coordinates. Mapped vertical cross sections and mean profiles of reflectivity from the PR, EDOP, and ground-based radars are compared for six cases. These cases cover a stratiform frontal rainband, convective cells of various sizes and stages, and a hurricane. For precipitating systems that are large relative to the PR footprint size, PR reflectivity profiles compare very well to high-resolution measurements thresholded to the PR minimum reflectivity, and derived variables such as bright band height and rain types are accurate, even at high PR incidence angles. It was found that for, the PR reflectivity of convective cells small relative to the PR footprint is weaker than in reality. Some of these differences can be explained by non-uniform beam filling. For other cases where strong reflectivity gradients occur within a PR footprint, the reflectivity distribution is spread out due to filtering by the PR antenna illumination pattern. In these cases, rain type classification may err and be biased towards the stratiform type, and the average reflectivity tends to be underestimated. The limited sensitivity of the PR implies that the upper regions of precipitation systems remain undetected and that the PR storm top height estimate is unreliable, usually underestimating the actual storm top height. This applies to all cases but the discrepancy is larger for smaller cells where limited sensitivity is compounded

  1. Repeat airborne LiDAR reveals the sensitivity of erosion and deposition patterns to bed topography and grain size distributions, Henry Mountains, Utah

    NASA Astrophysics Data System (ADS)

    Johnson, J. P.; Olinde, L.

    2013-12-01

    Repeat 2008 and 2011 NCALM airborne LiDAR data bracket a large 2010 storm over the Henry Mountains, Utah. This flood caused significant channel erosion and deposition, both of which locally exceeded 2 meters. We compare LiDAR difference maps to surface grain size distributions and channel bed topography to better understand factors that influenced the spatial distributions of elevation changes. Complete river bed topography was resolved over many kilometers because channels were dry when scanned. Systematic variations in grain size distributions among channels were measured by conducting pebble counts. Individual counts consisted of a minimum of 250 measured clasts to allow for robust statistics on coarse grain distributions, with grain sizes ranging from sand to boulders. Bed topography maps and field measurements indicate that channel morphology varies systematically with local grain size distributions and in particular with the abundance of boulders. Reach morphologies range from step-pools to gravel plane-beds along individual channels. We generalize channel topography using various roughness metrics and apply similar metrics to the spatial distribution of topographic changes. Channel width constrictions, common in these canyons, tend to cause net deposition upstream and erosion downstream of these reaches. We also found that areas of erosion and deposition tend to change more abruptly along channels with coarser sediment because immobile grains (often large boulders) act as local base level controls. However, it appears that overall erosion and deposition patterns are not strongly correlated with local channel slope or other characteristics of reach morphology. We interpret this to indicate that before the 2010 flood, channel reaches were already adjusted to local flow conditions in previous floods, through surface grain size sorting and other morphological adjustments. Although erosion and deposition were locally significant from the 2010 flood, most channel

  2. Capillary photoionization: a high sensitivity ionization method for mass spectrometry.

    PubMed

    Haapala, Markus; Suominen, Tina; Kostiainen, Risto

    2013-06-18

    We present a capillary photoionization (CPI) method for mass spectrometric (MS) analysis of liquid and gaseous samples. CPI utilizes a heated transfer capillary with a vacuum ultraviolet transparent MgF2 window, through which vacuum UV light (10 eV) from an external source enters the capillary. The liquid or gaseous sample, together with dopant, is introduced directly into the heated transfer capillary between the atmosphere and the vacuum of the MS. Since the sample is vaporized and photoionized inside the capillary, ion transmission is maximized, resulting in good overall sensitivity for nonpolar and polar compounds. As in atmospheric pressure photoionization, ionization in CPI occurs either by proton transfer or by charge exchange reactions. The feasibility of CPI was demonstrated with selected nonpolar and polar compounds. A particular advantage of CPI is that it enables the analysis of nonvolatile and nonpolar compounds in liquid samples with high ionization efficiency. This is not possible with existing capillary ionization methods. The performance of CPI as an interface between GC and MS and its applicability for the analysis of steroids in biological samples are also demonstrated. The GC-CPI-MS method shows good chromatographic resolution, linearity (R(2) > 0.993), limits of detection (LOD) in the range of 2-6 pg/mL and repeatability of injection with relative standard deviations of 4-15%. PMID:23713722

  3. Improvement of sensitivity in high-resolution Rutherford backscattering spectroscopy

    SciTech Connect

    Hashimoto, H.; Nakajima, K.; Suzuki, M.; Kimura, K.; Sasakawa, K.

    2011-06-15

    The sensitivity (limit of detection) of high-resolution Rutherford backscattering spectroscopy (HRBS) is mainly determined by the background noise of the spectrometer. There are two major origins of the background noise in HRBS, one is the stray ions scattered from the inner wall of the vacuum chamber of the spectrometer and the other is the dark noise of the microchannel plate (MCP) detector which is commonly used as a focal plane detector of the spectrometer in HRBS. In order to reject the stray ions, several barriers are installed inside the spectrometer and a thin Mylar foil is mounted in front of the detector. The dark noise of the MCP detector is rejected by the coincidence measurement with the secondary electrons emitted from the Mylar foil upon the ion passage. After these improvements, the background noise is reduced by a factor of 200 at a maximum. The detection limit can be improved down to 10 ppm for As in Si at a measurement time of 1 h under ideal conditions.

  4. Physical activity and high-sensitivity C-reactive protein.

    PubMed

    Plaisance, Eric P; Grandjean, Peter W

    2006-01-01

    Cardiovascular disease (CVD) remains one of the leading causes of death and disability in developed countries around the world despite the documented success of lifestyle and pharmacological interventions. This illustrates the multifactorial nature of atherosclerosis and the use of novel inflammatory markers as an adjunct to risk factor reduction strategies. As evidence continues to accumulate that inflammation is involved in all stages of the development and progression of atherosclerosis, markers of inflammation such as high-sensitivity C-reactive protein (CRP) may provide additional information regarding the biological status of the atherosclerotic lesion. Recent investigations suggest that physical activity reduces CRP levels. Higher levels of physical activity and cardiorespiratory fitness are consistently associated with 6-35% lower CRP levels. Longitudinal training studies that have demonstrated reductions in CRP concentrations range from 16% to 41%, an effect that may be independent of baseline levels of CRP, body composition or weight loss. The average change in CRP associated with physical activity appears to be at least as good, if not better, than currently prescribed pharmacological interventions in similar populations. The primary purpose of this review will be to present evidence from both cross-sectional and longitudinal investigations that physical activity lowers CRP levels in a dose-response manner. Finally, this review will examine factors such as body composition, sex, blood sample timing, diet and smoking, which may influence the CRP response to physical activity. PMID:16646631

  5. A Highly Sensitive Genetic Protocol to Detect NF1 Mutations

    PubMed Central

    Carmen Valero, María; Martín, Yolanda; Hernández-Imaz, Elisabete; Marina Hernández, Alba; Meleán, Germán; María Valero, Ana; Javier Rodríguez-Álvarez, Francisco; Tellería, Dolores; Hernández-Chico, Concepción

    2011-01-01

    Neurofibromatosis type 1 (NF1) is a hereditary disorder caused by mutations in the NF1 gene. Detecting mutation in NF1 is hindered by the gene's large size, the lack of mutation hotspots, the presence of pseudogenes, and the wide variety of possible lesions. We developed a method for detecting germline mutations by combining an original RNA-based cDNA-PCR mutation detection method and denaturing high-performance liquid chromatography (DHPLC) with multiplex ligation-dependent probe amplification (MLPA). The protocol was validated in a cohort of 56 blood samples from NF1 patients who fulfilled NIH diagnostic criteria, identifying the germline mutation in 53 cases (95% sensitivity). The efficiency and reliability of this approach facilitated detection of different types of mutations, including single-base substitutions, deletions or insertions of one to several nucleotides, microdeletions, and changes in intragenic copy number. Because mutational screening for minor lesions was performed using cDNA and the characterization of mutated alleles was performed at both the RNA and genomic DNA level, the analysis provided insight into the nature of the different mutations and their effect on NF1 mRNA splicing. After validation, we implemented the protocol as a routine test. Here we present the overall unbiased spectrum of NF1 mutations identified in 93 patients in a cohort of 105. The results indicate that this protocol is a powerful new tool for the molecular diagnosis of NF1. PMID:21354044

  6. High-sensitivity detection of negative ions in the stratosphere

    NASA Astrophysics Data System (ADS)

    McCrumb, J. L.; Arnold, F.

    1981-11-01

    High-sensitivity, in situ measurements of the negative ion composition of the stratosphere are presented which have led to the detection of previously unobserved ion species. The balloon-borne measurements were made by an instrument consisting of a cryogenically pumped quadrupole mass filter with single ion detection by a channel electron multiplier operating in a pulse-saturated ion counting mode, with an ion detection limit of about 1 ion/cu cm. Mass spectra taken during a daytime flight over southwestern France at a float altitude of 34 km reveal the presence of ions in the families NO3(-)(HNO3)(a) and HSO4(-)(H2SO4)(b)(HNO3)(c) at fractional ion count rates between 0.9 and 6.5%. Minor ions detected at count rates between 0.05 and 0.4% include those containing NO3(-) and HSO4(-) cores, as well as CN(-) and CO3 and CO3(-).H2O. Ligands identified for these molecules include HNO3 and H2SO4 and, tentatively, H2O, HCl, HNO2 and HOCl. An atmospheric nitric acid concentration of 7 x 10 to the 7th/cu cm is estimated on the basis of the NO3(-) and HNO3 species data.

  7. Hi-net: High sensitivity seismograph network, Japan

    NASA Astrophysics Data System (ADS)

    Obara, Kazushige

    The high sensitivity seismograph network in Japan (Hi-net), composed of around 600 seismic stations, is a part of the project made by ‘The Headquarter for Earthquake Research Promotion’ after 1995 Hyogoken-nanbu Earthquake and has been constructed and operated by National Research Institute for Earth Science and Disaster Prevention (NIED). Seismic stations are distributed homogeneously covering whole Japan Islands with an average spacing of 20 30 km. Three-component short period velocity seismometers are installed at the bottom of boreholes with depth of 100 m or deeper. Seismic data are digitized by 24-bit A/D converter and decimated to 27bit data with the sampling frequency of 100Hz. Stations are connected to the Hi-net data center, NIED in Tsukuba by a frame relay network service. TCP/IP and SNMP are used for data transmission and network management, respectively. The data are continuously transmitted to the data center and local offices of Japan Meteorological Agency for routine monitoring of seismic activity. The data receiving, monitoring, processing, and archiving system is controlled by a database management system in the data center. Event detection, phase picking, hypocentral determination, spectra analyses, and extracting waveform parameters are processed automatically. Event information and continuous waveform data are available through the world-wide-web.

  8. Highly sensitive hot electron bolometer based on disordered graphene.

    PubMed

    Han, Qi; Gao, Teng; Zhang, Rui; Chen, Yi; Chen, Jianhui; Liu, Gerui; Zhang, Yanfeng; Liu, Zhongfan; Wu, Xiaosong; Yu, Dapeng

    2013-01-01

    A bolometer is a device that makes an electrical resistive response to the electromagnetic radiation resulted from a raise of temperature due to heating. The combination of the extremely weak electron-phonon interactions along with its small electron heat capacity makes graphene an ideal material for applications in ultra-fast and sensitive hot electron bolometer. However, a major issue is that the resistance of pristine graphene weakly depends on the electronic temperature. We propose using disordered graphene to obtain a strongly temperature dependent resistance. The measured electrical responsivity of the disordered graphene bolometer reaches 6 × 10(6) V/W at 1.5 K, corresponding to an optical responsivity of 1.6 × 10(5) V/W. The deduced electrical noise equivalent power is 1.2 fW/√Hz, corresponding to the optical noise equivalent power of 44 fW/√Hz. The minimal device structure and no requirement for high mobility graphene make a step forward towards the applications of graphene hot electron bolometers. PMID:24346418

  9. Highly sensitive hot electron bolometer based on disordered graphene

    PubMed Central

    Han, Qi; Gao, Teng; Zhang, Rui; Chen, Yi; Chen, Jianhui; Liu, Gerui; Zhang, Yanfeng; Liu, Zhongfan; Wu, Xiaosong; Yu, Dapeng

    2013-01-01

    A bolometer is a device that makes an electrical resistive response to the electromagnetic radiation resulted from a raise of temperature due to heating. The combination of the extremely weak electron-phonon interactions along with its small electron heat capacity makes graphene an ideal material for applications in ultra-fast and sensitive hot electron bolometer. However, a major issue is that the resistance of pristine graphene weakly depends on the electronic temperature. We propose using disordered graphene to obtain a strongly temperature dependent resistance. The measured electrical responsivity of the disordered graphene bolometer reaches 6 × 106 V/W at 1.5 K, corresponding to an optical responsivity of 1.6 × 105 V/W. The deduced electrical noise equivalent power is 1.2 , corresponding to the optical noise equivalent power of 44 . The minimal device structure and no requirement for high mobility graphene make a step forward towards the applications of graphene hot electron bolometers. PMID:24346418

  10. ASIC for High Rate 3D Position Sensitive Detectors

    SciTech Connect

    Vernon, E.; De Geronimo, G.; Ackley, K.; Fried, J.; He, Z.; Herman, C.; Zhang, F.

    2010-06-16

    We report on the development of an application specific integrated circuit (ASIC) for 3D position sensitive detectors (3D PSD). The ASIC is designed to operate with pixelated wide bandgap sensors like Cadmium-Zinc-Telluride (CZT), Mercuric Iodide (Hgl2) and Thallium Bromide (TIBr). It measures the amplitudes and timings associated with an ionizing event on 128 anodes, the anode grid, and the cathode. Each channel provides low-noise charge amplification, high-order shaping with peaking time adjustable from 250 ns to 12 {micro}s, gain adjustable to 20 mV/fC or 120 mV/fC (for a dynamic range of 3.2 MeV and 530 keV in CZT), amplitude discrimination with 5-bit trimming, and positive and negative peak and timing detections. The readout can be full or sparse, based on a flag and single- or multi-cycle token passing. All channels, triggered channels only, or triggered with neighbors can be read out thus increasing the rate capability of the system to more than 10 kcps. The ASIC dissipates 330 mW which corresponds to about 2.5 mW per channel.

  11. Highly sensitive tube-topology magnetoelectric magnetic sensors

    NASA Astrophysics Data System (ADS)

    Gillette, Scott Matthew

    Magnetoelectric (ME) composites have drawn increasing interest in recent years due to advancements in the technology resulting in enhanced ME coupling coefficients, stable room-temperature operation, sub-nanoTesla noise floor, low- and zero-biased operation, and fabrication of compact, miniaturized devices. Now, more than ever, practical use of ME devices in commercial magnetometry applications is feasible, while continued development of numerous other applications, such as voltage-tunable magnetic field generators, voltage-tunable inductors, and magnetically-tunable capacitors, bolster the overall usefulness of ME composites as a valuable technology. This dissertation focuses on development and characterization of tube-topology ME composites as magnetic field sensors. The novel topology is most notable for demonstrating high zero-external-bias sensitivity, low noise floor, low-frequency bandwidth, and self-powered, stable room temperature operation. Numerous characterization studies are included in this work where several devices are analyzed as a function of test-field, DC-bias field, geometry, material choice, and more. The overall conclusions drawn upon these results indicate strongly that the tube-topology ME magnetic field sensor holds promise to compete with existing hall-effect and flux-gate magnetometers. ME composites are at the tipping point of commercialization for use in magnetometry applications and are emerging as a valuable technology for use in numerous creative ways.

  12. Laser Imaging of Airborne Acoustic Emission by Nonlinear Defects

    NASA Astrophysics Data System (ADS)

    Solodov, Igor; Döring, Daniel; Busse, Gerd

    2008-06-01

    Strongly nonlinear vibrations of near-surface fractured defects driven by an elastic wave radiate acoustic energy into adjacent air in a wide frequency range. The variations of pressure in the emitted airborne waves change the refractive index of air thus providing an acoustooptic interaction with a collimated laser beam. Such an air-coupled vibrometry (ACV) is proposed for detecting and imaging of acoustic radiation of nonlinear spectral components by cracked defects. The photoelastic relation in air is used to derive induced phase modulation of laser light in the heterodyne interferometer setup. The sensitivity of the scanning ACV to different spatial components of the acoustic radiation is analyzed. The animated airborne emission patterns are visualized for the higher harmonic and frequency mixing fields radiated by planar defects. The results confirm a high localization of the nonlinear acoustic emission around the defects and complicated directivity patterns appreciably different from those observed for fundamental frequencies.

  13. High throughput modular chambers for rapid evaluation of anesthetic sensitivity

    PubMed Central

    Sun, Yi; Chen, Jingqiu; Pruckmayr, Gregory; Baumgardner, James E; Eckmann, David M; Eckenhoff, Roderic G; Kelz, Max B

    2006-01-01

    Background Anesthetic sensitivity is determined by the interaction of multiple genes. Hence, a dissection of genetic contributors would be aided by precise and high throughput behavioral screens. Traditionally, anesthetic phenotyping has addressed only induction of anesthesia, evaluated with dose-response curves, while ignoring potentially important data on emergence from anesthesia. Methods We designed and built a controlled environment apparatus to permit rapid phenotyping of twenty-four mice simultaneously. We used the loss of righting reflex to indicate anesthetic-induced unconsciousness. After fitting the data to a sigmoidal dose-response curve with variable slope, we calculated the MACLORR (EC50), the Hill coefficient, and the 95% confidence intervals bracketing these values. Upon termination of the anesthetic, Emergence timeRR was determined and expressed as the mean ± standard error for each inhaled anesthetic. Results In agreement with several previously published reports we find that the MACLORR of halothane, isoflurane, and sevoflurane in 8–12 week old C57BL/6J mice is 0.79% (95% confidence interval = 0.78 – 0.79%), 0.91% (95% confidence interval = 0.90 – 0.93%), and 1.96% (95% confidence interval = 1.94 – 1.97%), respectively. Hill coefficients for halothane, isoflurane, and sevoflurane are 24.7 (95% confidence interval = 19.8 – 29.7%), 19.2 (95% confidence interval = 14.0 – 24.3%), and 33.1 (95% confidence interval = 27.3 – 38.8%), respectively. After roughly 2.5 MACLORR • hr exposures, mice take 16.00 ± 1.07, 6.19 ± 0.32, and 2.15 ± 0.12 minutes to emerge from halothane, isoflurane, and sevoflurane, respectively. Conclusion This system enabled assessment of inhaled anesthetic responsiveness with a higher precision than that previously reported. It is broadly adaptable for delivering an inhaled therapeutic (or toxin) to a population while monitoring its vital signs, motor reflexes, and providing precise control over environmental

  14. High sensitivity Moire interferometry with phase shifting at nano resolution

    NASA Astrophysics Data System (ADS)

    Chen, Bicheng

    Due to insatiate demand for miniaturization of electronics, there is a need for new techniques to measure full-field strain at micro-scale structures. In addition, Micro-Electronic-Mechanical-Systems (MEMS) require a high resolution and high sensitivity material property characterization technique. In this study, a theoretic model for a high sensitivity Moire Interferometry (MI) for measuring nano-scale strain field has been developed. The study also includes the application of the proposed measurement technique for the study of reliability of next generation nano-electronics/power electronics. The study includes both theoretical and experimental work. In the theoretical part, a far field modeling of a Moire Interferometer (MI) using the mode decomposition method is proposed according to the analytical formulation from the scalar diffraction theory. The wave propagation within the defined MI far field domain is solved analytically for a single frequency surface relieved grating structure following the Rayleigh-Sommerfeld formulation under the paraxial approximation. It is shown that the far-field electrical field and the intensity interferogram can be calculated using the mode decomposition method. Furthermore, the near-field (propagation distance < 1 mum) assumptions are validated using exact electromagnetic (EM) theory; and the EM fields are simulated in a few microns region above the surface of the diffraction grating. The study shows that there is a strong correlation (correlation factor R = 0.869) of spatial frequency response between EM field and strain field at the nanoscale. Experimentally, a 164 nm/pixel spatial resolution Moire Interferometer with automated full strain field calculation is proposed. Accurate full strain field maps are generated automatically by a combination of phase shifting technique (temporal data redundancy) and Continuous Wavelet Transform (CWT) (spatial data redundancy). A thermal experiment on BGA packaging is used to demonstrate

  15. Application of high resolution airborne geophysical data in geological modelling of Mohar Cauldron Complex, Bundelkhand Massif, central India: implications for uranium exploration

    NASA Astrophysics Data System (ADS)

    Markandeyulu, A. 13Chaturvedi, A. K. 1Raju, B. V. S. N. 1Parihar, P. S. 1Miller, Roger 2Gooch, Glenn

    2014-03-01

    The Mohar cauldron, located near Mohar village, Shivpuri District, Madhya Pradesh, India, represents an explosive felsic volcanic event. The Mohar Cauldron Complex (MCC) is an important target area for uranium exploration as collapse breccias associated with extensional tectonics are traditionally important for multi-metal deposits, including uranium. Advanced processing and interpretation of the high resolution airborne electromagnetic (AEM), magnetic and radiometric data acquired over the Mohar cauldron and the surrounding environs by Fugro Airborne surveys, successfully mapped the major geological domains in the area based on their distinct geophysical characteristics. Interpretation of the data indicated the presence of three felsic intrusive bodies, only one of which, the MCC, reached the surface and collapsed. Variation in the geophysical characteristics of the three bodies is attributed to variations in hydrothermal alteration. Magnetic signature and radiometric response of the MCC and surrounding area also show signs of intense alteration. AEM data has allowed the boundary of the sediments within the MCC to be mapped accurately, along with the surrounding brecciated zone. Conductivity depth imaging calculated to a depth of 500 m clearly indicated the geometry and disposition of different layers of MCC. 3D voxel modelling of the MCC also allowed for the identification of the different lithologies that constitute the cauldron structure. 3D conductivity isosurfaces provided a thorough understanding of the subsurface distribution of conductivities.

  16. High-sensitivity high-throughput chip based biosensor array for multiplexed detection of heavy metals

    NASA Astrophysics Data System (ADS)

    Yan, Hai; Tang, Naimei; Jairo, Grace A.; Chakravarty, Swapnajit; Blake, Diane A.; Chen, Ray T.

    2016-03-01

    Heavy metal ions released into the environment from industrial processes lead to various health hazards. We propose an on-chip label-free detection approach that allows high-sensitivity and high-throughput detection of heavy metals. The sensing device consists of 2-dimensional photonic crystal microcavities that are combined by multimode interferometer to form a sensor array. We experimentally demonstrate the detection of cadmium-chelate conjugate with concentration as low as 5 parts-per-billion (ppb).

  17. Quantification of gully volume using very high resolution DSM generated through 3D reconstruction from airborne and field digital imagery

    NASA Astrophysics Data System (ADS)

    Castillo, Carlos; Zarco-Tejada, Pablo; Laredo, Mario; Gómez, Jose Alfonso

    2013-04-01

    Major advances have been made recently in automatic 3D photo-reconstruction techniques using uncalibrated and non-metric cameras (James and Robson, 2012). However, its application on soil conservation studies and landscape feature identification is currently at the outset. The aim of this work is to compare the performance of a remote sensing technique using a digital camera mounted on an airborne platform, with 3D photo-reconstruction, a method already validated for gully erosion assessment purposes (Castillo et al., 2012). A field survey was conducted in November 2012 in a 250 m-long gully located in field crops on a Vertisol in Cordoba (Spain). The airborne campaign was conducted with a 4000x3000 digital camera installed onboard an aircraft flying at 300 m above ground level to acquire 6 cm resolution imagery. A total of 990 images were acquired over the area ensuring a large overlap in the across- and along-track direction of the aircraft. An ortho-mosaic and the digital surface model (DSM) were obtained through automatic aerial triangulation and camera calibration methods. For the field-level photo-reconstruction technique, the gully was divided in several reaches to allow appropriate reconstruction (about 150 pictures taken per reach) and, finally, the resulting point clouds were merged into a unique mesh. A centimetric-accuracy GPS provided a benchmark dataset for gully perimeter and distinguishable reference points in order to allow the assessment of measurement errors of the airborne technique and the georeferenciation of the photo-reconstruction 3D model. The uncertainty on the gully limits definition was explicitly addressed by comparison of several criteria obtained by 3D models (slope and second derivative) with the outer perimeter obtained by the GPS operator identifying visually the change in slope at the top of the gully walls. In this study we discussed the magnitude of planimetric and altimetric errors and the differences observed between the

  18. Requirements analysis of airborne gravity gradiometry on moving-based platform

    NASA Astrophysics Data System (ADS)

    Tu, L.; Li, Z.; Wu, W.

    2014-12-01

    Airborne gravity and gravity gradient measurement are the most effective ways for the earth gravitational field measurement. Gravity gradient is a derivative of gravity acceleration, due to the high order feature of gravity gradient, it is more sensitive to short wave component, and can reflect the details of the source so that the gravity gradient measurement has wide applications in geophysical science, resource exploration, and inertial navigation. Airborne gravity gradient measurement uses the plane or ship as the platform, and it is efficient and high precision. In this paper, We compared the gravity and gravity gradient measurement, and analyzed the advantages of the gravity gradient measurement compared with gravity measurement. The airborne gravity gradient measurement system and the inertial stabilization platform were discussed. By setting a goal sensitivity of the gravity gradient measurement being 1 E/√Hz, the key factors of the stabilized platform, namely the pointing accuracy, pointing stability, and gyroscope random drift, are 0.5°, 0.01°/hr/√Hz, and 0.01°/hr respectively. Compared with the airborne gravity measurement whose goal sensitivity is 1mGal/√Hz, the requirements of moving-based gravity gradient measurement on the inertial stabilization platform is significantly lower and hence easy to realize, and the major reason is the differential measurement mode being used.

  19. Airborne transmission of lyssaviruses.

    PubMed

    Johnson, N; Phillpotts, R; Fooks, A R

    2006-06-01

    In 2002, a Scottish bat conservationist developed a rabies-like disease and subsequently died. This was caused by infection with European bat lyssavirus 2 (EBLV-2), a virus closely related to Rabies virus (RABV). The source of this infection and the means of transmission have not yet been confirmed. In this study, the hypothesis that lyssaviruses, particularly RABV and the bat variant EBLV-2, might be transmitted via the airborne route was tested. Mice were challenged via direct introduction of lyssavirus into the nasal passages. Two hours after intranasal challenge with a mouse-adapted strain of RABV (Challenge Virus Standard), viral RNA was detectable in the tongue, lungs and stomach. All of the mice challenged by direct intranasal inoculation developed disease signs by 7 days post-infection. Two out of five mice challenged by direct intranasal inoculation of EBLV-2 developed disease between 16 and 19 days post-infection. In addition, a simple apparatus was evaluated in which mice could be exposed experimentally to infectious doses of lyssavirus from an aerosol. Using this approach, mice challenged with RABV, but not those challenged with EBLV-2, were highly susceptible to infection by inhalation. These data support the hypothesis that lyssaviruses, and RABV in particular, can be spread by airborne transmission in a dose-dependent manner. This could present a particular hazard to personnel exposed to aerosols of infectious RABV following accidental release in a laboratory environment. PMID:16687600

  20. Impact detection on airborne multilayered structures

    NASA Astrophysics Data System (ADS)

    Noharet, Bertrand; Chazelas, Jean; Bonniau, Philippe; Lecuellet, Jerome; Turpin, Marc J.

    1995-04-01

    This paper reviews the progress of an ongoing research program at Thomson-CSF and Bertin & Cie which addresses an optical fiber system dedicated to the assessment of impact induced damages on airborne multilayered structures. The method is based on the use of embedded high birefringence optical fiber sensors and distributed white light interfero-polarimetry. The first part is devoted to the transduction process efficiency within optical fibers depending on the applied force intensity, direction versus the fiber eigen axes and the interaction length. To understand the behavior of these optical fibers and calibrate the detection system, experiments have been conducted on elliptical core fibers, `bow-tie' fibers and side-hole fibers and showed a wide range of available sensitivities. The second step is related to the inclusion of optical fibers in a sandwich structure representative of an airborne dome, and composed of foam between glass/epoxy composite skins. Different designs of grooves in the foam and tube sheathings have been investigated to support and protect the optical fiber. Impacts have been performed on the structure in the 1 to 10 Joules energy range. Experimental impact location and energy measurements have been achieved for a variety of stress fields.

  1. Stochastic sensitivity measure for mistuned high-performance turbines

    NASA Technical Reports Server (NTRS)

    Murthy, Durbha V.; Pierre, Christophe

    1992-01-01

    A stochastic measure of sensitivity is developed in order to predict the effects of small random blade mistuning on the dynamic aeroelastic response of turbomachinery blade assemblies. This sensitivity measure is based solely on the nominal system design (i.e., on tuned system information), which makes it extremely easy and inexpensive to calculate. The measure has the potential to become a valuable design tool that will enable designers to evaluate mistuning effects at a preliminary design stage and thus assess the need for a full mistuned rotor analysis. The predictive capability of the sensitivity measure is illustrated by examining the effects of mistuning on the aeroelastic modes of the first stage of the oxidizer turbopump in the Space Shuttle Main Engine. Results from a full analysis mistuned systems confirm that the simple stochastic sensitivity measure predicts consistently the drastic changes due to misturning and the localization of aeroelastic vibration to a few blades.

  2. High angular sensitivity thin film tin oxide sensor

    NASA Astrophysics Data System (ADS)

    Kaur, Davinder; Madaan, Divya; Sharma, V. K.; Kapoor, A.

    2016-05-01

    We present theoretical anlaysis of a thin film SnO2 (Tin Oxide) sensor for the measurement of variation in the refractive index of the bulk media. It is based on lossy mode resonance between the absorbing thin film lossy modes and the evanescent wave. Also the addition of low index dielectric matching layer between the prism and the lossy waveguiding layer future increase the angular sensitivity and produce an efficient refractive index sensor. The angular interrogation is done and obtained sensitivity is 110 degree/RIU. Theoretical analysis of the proposed sensor based on Fresnel reflection coefficients is presented. This enhanced sensitivity will further improve the monitoring of biomolecular interactions and the higher sensitivity of the proposed configurations makes it to be a much better option to be employed for biosensing applications.

  3. Design of a High Sensitivity GNSS receiver for Lunar missions

    NASA Astrophysics Data System (ADS)

    Musumeci, Luciano; Dovis, Fabio; Silva, João S.; da Silva, Pedro F.; Lopes, Hugo D.

    2016-06-01

    This paper presents the design of a satellite navigation receiver architecture tailored for future Lunar exploration missions, demonstrating the feasibility of using Global Navigation Satellite Systems signals integrated with an orbital filter to achieve such a scope. It analyzes the performance of a navigation solution based on pseudorange and pseudorange rate measurements, generated through the processing of very weak signals of the Global Positioning System (GPS) L1/L5 and Galileo E1/E5 frequency bands. In critical scenarios (e.g. during manoeuvres) acceleration and attitude measurements from additional sensors complementing the GNSS measurements are integrated with the GNSS measurement to match the positioning requirement. A review of environment characteristics (dynamics, geometry and signal power) for the different phases of a reference Lunar mission is provided, focusing on the stringent requirements of the Descent, Approach and Hazard Detection and Avoidance phase. The design of High Sensitivity acquisition and tracking schemes is supported by an extensive simulation test campaign using a software receiver implementation and navigation results are validated by means of an end-to-end software simulator. Acquisition and tracking of GPS and Galileo signals of the L1/E1 and L5/E5a bands was successfully demonstrated for Carrier-to-Noise density ratios as low as 5-8 dB-Hz. The proposed navigation architecture provides acceptable performances during the considered critical phases, granting position and velocity errors below 61.4 m and 3.2 m/s, respectively, for the 99.7% of the mission time.

  4. Highly sensitive and unbiased approach for elucidating antibody repertoires.

    PubMed

    Lin, Sherry G; Ba, Zhaoqing; Du, Zhou; Zhang, Yu; Hu, Jiazhi; Alt, Frederick W

    2016-07-12

    Developing B lymphocytes undergo V(D)J recombination to assemble germ-line V, D, and J gene segments into exons that encode the antigen-binding variable region of Ig heavy (H) and light (L) chains. IgH and IgL chains associate to form the B-cell receptor (BCR), which, upon antigen binding, activates B cells to secrete BCR as an antibody. Each of the huge number of clonally independent B cells expresses a unique set of IgH and IgL variable regions. The ability of V(D)J recombination to generate vast primary B-cell repertoires results from a combinatorial assortment of large numbers of different V, D, and J segments, coupled with diversification of the junctions between them to generate the complementary determining region 3 (CDR3) for antigen contact. Approaches to evaluate in depth the content of primary antibody repertoires and, ultimately, to study how they are further molded by secondary mutation and affinity maturation processes are of great importance to the B-cell development, vaccine, and antibody fields. We now describe an unbiased, sensitive, and readily accessible assay, referred to as high-throughput genome-wide translocation sequencing-adapted repertoire sequencing (HTGTS-Rep-seq), to quantify antibody repertoires. HTGTS-Rep-seq quantitatively identifies the vast majority of IgH and IgL V(D)J exons, including their unique CDR3 sequences, from progenitor and mature mouse B lineage cells via the use of specific J primers. HTGTS-Rep-seq also accurately quantifies DJH intermediates and V(D)J exons in either productive or nonproductive configurations. HTGTS-Rep-seq should be useful for studies of human samples, including clonal B-cell expansions, and also for following antibody affinity maturation processes. PMID:27354528

  5. Identification of damage in buildings based on gaps in 3D point clouds from very high resolution oblique airborne images

    NASA Astrophysics Data System (ADS)

    Vetrivel, Anand; Gerke, Markus; Kerle, Norman; Vosselman, George

    2015-07-01

    Point clouds generated from airborne oblique images have become a suitable source for detailed building damage assessment after a disaster event, since they provide the essential geometric and radiometric features of both roof and façades of the building. However, they often contain gaps that result either from physical damage or from a range of image artefacts or data acquisition conditions. A clear understanding of those reasons, and accurate classification of gap-type, are critical for 3D geometry-based damage assessment. In this study, a methodology was developed to delineate buildings from a point cloud and classify the present gaps. The building delineation process was carried out by identifying and merging the roof segments of single buildings from the pre-segmented 3D point cloud. This approach detected 96% of the buildings from a point cloud generated using airborne oblique images. The gap detection and classification methods were tested using two other data sets obtained with Unmanned Aerial Vehicle (UAV) images with a ground resolution of around 1-2 cm. The methods detected all significant gaps and correctly identified the gaps due to damage. The gaps due to damage were identified based on the surrounding damage pattern, applying Gabor wavelets and a histogram of gradient orientation features. Two learning algorithms - SVM and Random Forests were tested for mapping the damaged regions based on radiometric descriptors. The learning model based on Gabor features with Random Forests performed best, identifying 95% of the damaged regions. The generalization performance of the supervised model, however, was less successful: quality measures decreased by around 15-30%.

  6. High-intensity xenon plasma discharge lamp for bulk-sensitive high-resolution photoemission spectroscopy

    SciTech Connect

    Souma, S.; Sato, T.; Takahashi, T.; Baltzer, P.

    2007-12-15

    We have developed a highly brilliant xenon (Xe) discharge lamp operated by microwave-induced electron cyclotron resonance (ECR) for ultrahigh-resolution bulk-sensitive photoemission spectroscopy (PES). We observed at least eight strong radiation lines from neutral or singly ionized Xe atoms in the energy region of 8.4-10.7 eV. The photon flux of the strongest Xe I resonance line at 8.437 eV is comparable to that of the He I{alpha} line (21.218 eV) from the He-ECR discharge lamp. Stable operation for more than 300 h is achieved by efficient air-cooling of a ceramic tube in the resonance cavity. The high bulk sensitivity and high-energy resolution of PES using the Xe lines are demonstrated for some typical materials.

  7. Novel Ruthenium Sensitizers with a Phenothiazine Conjugated Bipyridyl Ligand for High-Efficiency Dye-Sensitized Solar Cells.

    PubMed

    She, Zhijie; Cheng, Yangyang; Zhang, Luoqiang; Li, Xiaoyu; Wu, Di; Guo, Qiang; Lan, Jingbo; Wang, Ruilin; You, Jingsong

    2015-12-23

    Two efficient ruthenium sensitizers with a phenothiazine-modified bipyridine as an ancillary ligand, coded SCZ-1 and SCZ-2, have been developed as dyes in dye-sensitized solar cells (DSSCs). Both sensitizers exhibit low-energy metal-to-ligand charge transfer (MLCT) bands centered at 539 nm with high molar extinction coefficients of 1.77 × 10(4) M(-1) cm(-1) for SCZ-1 and 1.66 × 10(4) M(-1) cm(-1) for SCZ-2, which are significantly higher than the corresponding value for the reference N719 (1.27 × 10(4) M(-1) cm(-1)), indicating that the light-harvesting capacity of ruthenium sensitizers can be reinforced by introducing phenothiazine moieties into the bipyridine ligand. Under AM 1.5G irradiation (100 mW cm(-2)), SCZ-1 and SCZ-2 sensitized DSSC devices show impressive power conversion efficiencies (PCE) up to 10.4% by using of iodide-based electrolytes, which exceeds that of N719 (9.9%) under the same conditions. Both of the open circuit voltage (VOC) and fill factor (FF) of SCZ-sensitized solar cells approximate to those of N719-sensitized cell. The relatively higher efficiencies of the SCZ-sensitized cells than that of N719-sensitized cell come from their higher short-circuit photocurrent density (JSC), which may be mainly attributed to the high absorption coefficient. The absorption spectrum and device efficiency of SCZ-1 are both quite close to those of SCZ-2, suggesting that the difference in alkyl chains on the N atom of phenothiazine is not a decisive factor in affecting the photovoltaic performance of dyes. PMID:26624527

  8. Infrared airborne spectroradiometer survey results in the western Nevada area

    NASA Technical Reports Server (NTRS)

    Collins, W.; Chang, S. H.; Kuo, J. T.

    1982-01-01

    The Mark II airborne spectroradiometer system was flown over several geologic test sites in western Nevada. The infrared mineral absorption bands were observed and recorded for the first time using an airborne system with high spectral resolution in the 2.0 to 2.5 micron region. The data show that the hydrothermal alteration zone minerals, carbonates, and other minerals are clearly visible in the airborne survey mode. The finer spectral features that distinguish the various minerals with infrared bands are also clearly visible in the airborne survey data. Using specialized computer pattern recognition methods, it is possible to identify mineralogy and map alteration zones and lithologies by airborne spectroradiometer survey techniques.

  9. Experimental feasibility of the airborne measurement of absolute oil fluorescence spectral conversion efficiency

    NASA Technical Reports Server (NTRS)

    Hoge, F. E.; Swift, R. N.

    1983-01-01

    Airborne lidar oil spill experiments carried out to determine the practicability of the AOFSCE (absolute oil fluorescence spectral conversion efficiency) computational model are described. The results reveal that the model is suitable over a considerable range of oil film thicknesses provided the fluorescence efficiency of the oil does not approach the minimum detection sensitivity limitations of the lidar system. Separate airborne lidar experiments to demonstrate measurement of the water column Raman conversion efficiency are also conducted to ascertain the ultimate feasibility of converting such relative oil fluorescence to absolute values. Whereas the AOFSCE model is seen as highly promising, further airborne water column Raman conversion efficiency experiments with improved temporal or depth-resolved waveform calibration and software deconvolution techniques are thought necessary for a final determination of suitability.

  10. Airborne oceanographic lidar system

    NASA Technical Reports Server (NTRS)

    Bressel, C.; Itzkan, I.; Nunes, J. E.; Hoge, F.

    1977-01-01

    The characteristics of an Airborne Oceanographic Lidar (AOL) are given. The AOL system is described and its potential for various measurement applications including bathymetry and fluorosensing is discussed.

  11. Highly sensitive flexible pressure sensors with microstructured rubber dielectric layers

    NASA Astrophysics Data System (ADS)

    Mannsfeld, Stefan C. B.; Tee, Benjamin C.-K.; Stoltenberg, Randall M.; Chen, Christopher V. H.-H.; Barman, Soumendra; Muir, Beinn V. O.; Sokolov, Anatoliy N.; Reese, Colin; Bao, Zhenan

    2010-10-01

    The development of an electronic skin is critical to the realization of artificial intelligence that comes into direct contact with humans, and to biomedical applications such as prosthetic skin. To mimic the tactile sensing properties of natural skin, large arrays of pixel pressure sensors on a flexible and stretchable substrate are required. We demonstrate flexible, capacitive pressure sensors with unprecedented sensitivity and very short response times that can be inexpensively fabricated over large areas by microstructuring of thin films of the biocompatible elastomer polydimethylsiloxane. The pressure sensitivity of the microstructured films far surpassed that exhibited by unstructured elastomeric films of similar thickness, and is tunable by using different microstructures. The microstructured films were integrated into organic field-effect transistors as the dielectric layer, forming a new type of active sensor device with similarly excellent sensitivity and response times.

  12. High Sensitivity SPECT for Small Animals and Plants

    SciTech Connect

    Mitchell, Gregory S.

    2015-02-28

    Imaging systems using single gamma-ray emitting radioisotopes typically implement collimators in order to form the images. However, a tradeoff in sensitivity is inherent in the use of collimators, and modern preclinical single-photon emission computed tomography (SPECT) systems detect a very small fraction of emitted gamma-rays (<0.3%). We have built a collimator-less system, which can reach sensitivity of 40% for 99mTc imaging, while still producing images of sufficient spatial resolution for certain applications in thin objects such as mice, small plants, and well plates used for in vitro experiments.

  13. High-sensitivity photoacoustic detection of chemical warfare agents

    NASA Astrophysics Data System (ADS)

    Pushkarsky, Michael B.; Webber, Michael E.; MacDonald, Tyson; Patel, C. Kumar N.

    2004-12-01

    We report sensitive and selective detection of Diisopropyl methylphosphonate (DIMP) - a decomposition product of Sarin and a common surrogate for the nerve gases - in presence of several gases expected to be interferences in an urban setting. By employing photoacosutic spectroscopy with broadly tunable CO2 laser as a radiation source we demonstrate detection sensitivity for DIMP in the presence of these interferences of better than 0.5 ppb in 60 second long measurement time, which satisfies most current homeland and military security requirements and validates the photoacoustic spectroscopy as a powerful technology for nerve gas sensing instrumentation.

  14. Self-concentrating buoyant glass microbubbles for high sensitivity immunoassays.

    PubMed

    Juang, Duane S; Hsu, Chia-Hsien

    2016-02-01

    Here, we report the novel application of a material with self-concentrating properties for enhancing the sensitivity of immunoassays. Termed as glass microbubbles, they are antibody functionalized buoyant hollow glass microspheres that simultaneously float and concentrate into a dense monolayer when dispensed in a liquid droplet. This self-concentrating charactaristic of the microbubbles allow for autonomous signal localization, which translates to a higher sensitivity compared to other microparticle-based immunoassays. We then demonstrated a "microbubble array" platform consisting of the glass microbubbles floating in a microfluidic liquid hemisphere array for performing multiplex immunoassays. PMID:26620967

  15. A high-sensitivity push-pull magnetometer

    SciTech Connect

    Breschi, E.; Grujić, Z. D.; Knowles, P.; Weis, A.

    2014-01-13

    We describe our approach to atomic magnetometry based on the push-pull optical pumping technique. Cesium vapor is pumped and probed by a resonant laser beam whose circular polarization is modulated synchronously with the spin evolution dynamics induced by a static magnetic field. The magnetometer is operated in a phase-locked loop, and it has an intrinsic sensitivity below 20fT/√(Hz), using a room temperature paraffin-coated cell. We use the magnetometer to monitor magnetic field fluctuations with a sensitivity of 300fT/√(Hz)

  16. Single Cell Proteomics with Ultra-High Sensitivity Mass Spectrometry

    SciTech Connect

    Frank, M

    2005-02-16

    This project was a joint LDRD project between PAT, CMS and NAI with the objective to develop an instrument that analyzes the biochemical composition of single cells in real-time using bioaerosol mass spectrometry (BAMS) combined with advanced laser desorption and ionization techniques. Applications include both biological defense, fundamental cell biology and biomedical research. BAMS analyzes the biochemical composition of single, micrometer-sized particles (such as bacterial cells or spores) that can be directly sampled from air or a suspension. BAMS is based on an earlier development of aerosol time of flight mass spectrometry (ATOFMS) by members of our collaboration [1,2]. Briefly, in ATOFMS and BAMS aerosol particles are sucked directly from the atmosphere into vacuum through a series of small orifices. As the particles approach the ion source region of the mass spectrometer, they cross and scatter light from two CW laser beams separated by a known distance. The timing of the two bursts of scattered light created by each ''tracked'' particle reveals the speed, location and size of the particle. This information then enables the firing of a high-intensity laser such that the resulting laser pulse desorbs and ionizes molecules from the tracked particle just as it reaches the center of the ion source region. The full spectrum of ions is then measured using a time-of-flight mass spectrometer. The ability to rapidly analyze individual particles is clearly applicable to the rapid detection of aerosolized biological warfare agents so long as agent particles can be made to produce mass spectra that are distinct from the spectra of harmless background particles. The pattern of ions formed is determined by the properties of the laser pulse, the particle, and, in aerosol matrix-assisted laser desorption/ionization (MALDI), also the MALDI matrix used. As a result, it is critical that the properties of the laser pulses used for desorption and ionization be carefully chosen

  17. Detecting Airborne Mercury by Use of Palladium Chloride

    NASA Technical Reports Server (NTRS)

    Ryan, Margaret; Shevade, Abhijit; Kisor, Adam; Homer, Margie; Jewell, April; Manatt, Kenneth; Torres, Julia; Soler, Jessica; Taylor, Charles

    2009-01-01

    Palladium chloride films have been found to be useful as alternatives to the gold films heretofore used to detect airborne elemental mercury at concentrations of the order of parts per billion (ppb). Somewhat more specifically, when suitably prepared palladium chloride films are exposed to parts-per-billion or larger concentrations of airborne mercury, their electrical resistances change by amounts large enough to be easily measurable. Because airborne mercury adversely affects health, it is desirable to be able to detect it with high sensitivity, especially in enclosed environments in which there is a risk of leakage of mercury from lamps or other equipment. The detection of mercury by use of gold films involves the formation of gold/mercury amalgam. Gold films offer adequate sensitivity for detection of airborne mercury and could easily be integrated into an electronic-nose system designed to operate in the temperature range of 23 to 28 C. Unfortunately, in order to regenerate a gold-film mercury sensor, one must heat it to a temperature of 200 C for several minutes in clean flowing air. In preparation for an experiment to demonstrate the present sensor concept, palladium chloride was deposited from an aqueous solution onto sets of gold electrodes and sintered in air to form a film. Then while using the gold electrodes to measure the electrical resistance of the films, the films were exposed, at a temperature of 25 C, to humidified air containing mercury at various concentrations from 0 to 35 ppb (see figure). The results of this and other experiments have been interpreted as signifying that sensors of this type can detect mercury in room-temperature air at concentrations of at least 2.5 ppb and can readily be regenerated at temperatures <40 C.

  18. Development of High Temperature/High Sensitivity Novel Chemical Resistive Sensor

    SciTech Connect

    Chen, Chonglin; Nash, Patrick; Ma, Chunrui; Enriquez, Erik; Wang, Haibing; Xu, Xing; Bao, Shangyong; Collins, Gregory

    2013-08-13

    The research has been focused to design, fabricate, and develop high temperature/high sensitivity novel multifunctional chemical sensors for the selective detection of fossil energy gases used in power and fuel systems. By systematically studying the physical properties of the LnBaCo{sub 2}O{sub 5+d} (LBCO) [Ln=Pr or La] thin-films, a new concept chemical sensor based high temperature chemical resistant change has been developed for the application for the next generation highly efficient and near zero emission power generation technologies. We also discovered that the superfast chemical dynamic behavior and an ultrafast surface exchange kinetics in the highly epitaxial LBCO thin films. Furthermore, our research indicates that hydrogen can superfast diffuse in the ordered oxygen vacancy structures in the highly epitaxial LBCO thin films, which suggest that the LBCO thin film not only can be an excellent candidate for the fabrication of high temperature ultra sensitive chemical sensors and control systems for power and fuel monitoring systems, but also can be an excellent candidate for the low temperature solid oxide fuel cell anode and cathode materials.

  19. SML resist processing for high-aspect-ratio and high-sensitivity electron beam lithography

    NASA Astrophysics Data System (ADS)

    Mohammad, Mohammad Ali; Dew, Steven K.; Stepanova, Maria

    2013-03-01

    A detailed process characterization of SML electron beam resist for high-aspect-ratio nanopatterning at high sensitivity is presented. SML contrast curves were generated for methyl isobutyl ketone (MIBK), MIBK/isopropyl alcohol (IPA) (1:3), IPA/water (7:3), n-amyl acetate, xylene, and xylene/methanol (3:1) developers. Using IPA/water developer, the sensitivity of SML was improved considerably and found to be comparable to benchmark polymethylmethacrylate (PMMA) resist without affecting the aspect ratio performance. Employing 30-keV exposures and ultrasonic IPA/water development, an aspect ratio of 9:1 in 50-nm half-pitch dense grating patterns was achieved representing a greater than two times improvement over PMMA. Through demonstration of 25-nm lift-off features, the pattern transfer performance of SML is also addressed.

  20. High-sensitivity DPSK receiver for high-bandwidth free-space optical communication links.

    PubMed

    Juarez, Juan C; Young, David W; Sluz, Joseph E; Stotts, Larry B

    2011-05-23

    A high-sensitivity modem and high-dynamic range optical automatic gain controller (OAGC) have been developed to provide maximum link margin and to overcome the dynamic nature of free-space optical links. A sensitivity of -48.9 dBm (10 photons per bit) at 10 Gbps was achieved employing a return-to-zero differential phase shift keying based modem and a commercial Reed-Solomon forward error correction system. Low-noise optical gain was provided by an OAGC with a noise figure of 4.1 dB (including system required input loses) and a dynamic range of greater than 60 dB. PMID:21643335

  1. Airborne Particulate Threat Assessment

    SciTech Connect

    Patrick Treado; Oksana Klueva; Jeffrey Beckstead

    2008-12-31

    Aerosol threat detection requires the ability to discern between threat agents and ambient background particulate matter (PM) encountered in the environment. To date, Raman imaging technology has been demonstrated as an effective strategy for the assessment of threat agents in the presence of specific, complex backgrounds. Expanding our understanding of the composition of ambient particulate matter background will improve the overall performance of Raman Chemical Imaging (RCI) detection strategies for the autonomous detection of airborne chemical and biological hazards. Improving RCI detection performance is strategic due to its potential to become a widely exploited detection approach by several U.S. government agencies. To improve the understanding of the ambient PM background with subsequent improvement in Raman threat detection capability, ChemImage undertook the Airborne Particulate Threat Assessment (APTA) Project in 2005-2008 through a collaborative effort with the National Energy Technology Laboratory (NETL), under cooperative agreement number DE-FC26-05NT42594. During Phase 1 of the program, a novel PM classification based on molecular composition was developed based on a comprehensive review of the scientific literature. In addition, testing protocols were developed for ambient PM characterization. A signature database was developed based on a variety of microanalytical techniques, including scanning electron microscopy, FT-IR microspectroscopy, optical microscopy, fluorescence and Raman chemical imaging techniques. An automated particle integrated collector and detector (APICD) prototype was developed for automated collection, deposition and detection of biothreat agents in background PM. During Phase 2 of the program, ChemImage continued to refine the understanding of ambient background composition. Additionally, ChemImage enhanced the APICD to provide improved autonomy, sensitivity and specificity. Deliverables included a Final Report detailing our

  2. Single nanobeam optical sensor with a high Q-factor and high sensitivity.

    PubMed

    Kim, Sejeong; Kim, Hwi-Min; Lee, Yong-Hee

    2015-11-15

    The miniaturization of optical sensors is essential for the realization of compact, portable, and cost-effective devices. Photonic crystal-based optical sensors, which have an ultra-small mode volume and footprint, have demonstrated remarkable recent progress in achieving a high figure-of-merit (FOM) in a sensor. Here, we report an optical sensor with a high Q-factor and high sensitivity based on a photonic crystal nanobeam using the second lowest air band-edge mode. We calculated that a nanobeam (n=3.4) in a water environment (n=1.33) has refractive-index sensitivity of ~631 nm/RIU, while the quality factor is greater than 23,300. Accordingly, a theoretical FOM of the sensor corresponds to >9500. To the best of our knowledge, experimental refractive-index sensitivity of 461 nm/RIU is the highest value among photonic crystal single nanobeam geometry. The simple geometry of uniform air hole sizes and lattice constants in the proposed nanobeam sensor allows easy fabrication and mechanical stability. PMID:26565872

  3. Acquisition, calibration, and performance of airborne high-resolution ADS40 SH52 sensor data for monitoring the Colorado River below Glen Canyon Dam

    NASA Astrophysics Data System (ADS)

    Davis, P. A.; Cagney, L. E.; Kohl, K. A.; Gushue, T. M.; Fritzinger, C.; Bennett, G. E.; Hamill, J. F.; Melis, T. S.

    2010-12-01

    Periodically, the Grand Canyon Monitoring and Research Center of the U.S. Geological Survey collects and interprets high-resolution (20-cm), airborne multispectral imagery and digital surface models (DSMs) to monitor the effects of Glen Canyon Dam operations on natural and cultural resources of the Colorado River in Grand Canyon. We previously employed the first generation of the ADS40 in 2000 and the Zeiss-Imaging Digital Mapping Camera (DMC) in 2005. Data from both sensors displayed band-image misregistration owing to multiple sensor optics and image smearing along abrupt scarps due to errors in image rectification software, both of which increased post-processing time, cost, and errors from image classification. Also, the near-infrared gain on the early, 8-bit ADS40 was not properly set and its signal was saturated for the more chlorophyll-rich vegetation, which limited our vegetation mapping. Both sensors had stereo panchromatic capability for generating a DSM. The ADS40 performed to specifications; the DMC failed. In 2009, we employed the new ADS40 SH52 to acquire 11-bit multispectral data with a single lens (20-cm positional accuracy), as well as stereo panchromatic data that provided a 1-m cell DSM (40-cm root-mean-square vertical error at one sigma). Analyses of the multispectral data showed near-perfect registration of its four band images at our 20-cm resolution, a linear response to ground reflectance, and a large dynamic range and good sensitivity (except for the blue band). Data were acquired over a 10-day period for the 450-km-long river corridor in which acquisition time and atmospheric conditions varied considerably during inclement weather. We received 266 orthorectified flightlines for the corridor, choosing to calibrate and mosaic the data ourselves to ensure a flawless mosaic with consistent, realistic spectral information. A linear least-squares cross-calibration of overlapping flightlines for the corridor showed that the dominate factors in

  4. Object-based assessment of burn severity in diseased forests using high-spatial and high-spectral resolution MASTER airborne imagery

    NASA Astrophysics Data System (ADS)

    Chen, Gang; Metz, Margaret R.; Rizzo, David M.; Dillon, Whalen W.; Meentemeyer, Ross K.

    2015-04-01

    Forest ecosystems are subject to a variety of disturbances with increasing intensities and frequencies, which may permanently change the trajectories of forest recovery and disrupt the ecosystem services provided by trees. Fire and invasive species, especially exotic disease-causing pathogens and insects, are examples of disturbances that together could pose major threats to forest health. This study examines the impacts of fire and exotic disease (sudden oak death) on forests, with an emphasis on the assessment of post-fire burn severity in a forest where trees have experienced three stages of disease progression pre-fire: early-stage (trees retaining dried foliage and fine twigs), middle-stage (trees losing fine crown fuels), and late-stage (trees falling down). The research was conducted by applying Geographic Object-Based Image Analysis (GEOBIA) to MASTER airborne images that were acquired immediately following the fire for rapid assessment and contained both high-spatial (4 m) and high-spectral (50 bands) resolutions. Although GEOBIA has gradually become a standard tool for analyzing high-spatial resolution imagery, high-spectral resolution data (dozens to hundreds of bands) can dramatically reduce computation efficiency in the process of segmentation and object-based variable extraction, leading to complicated variable selection for succeeding modeling. Hence, we also assessed two widely used band reduction algorithms, PCA (principal component analysis) and MNF (minimum noise fraction), for the delineation of image objects and the subsequent performance of burn severity models using either PCA or MNF derived variables. To increase computation efficiency, only the top 5 PCA and MNF and top 10 PCA and MNF components were evaluated, which accounted for 10% and 20% of the total number of the original 50 spectral bands, respectively. Results show that if no band reduction was applied the models developed for the three stages of disease progression had relatively

  5. Improvement in the light sensitivity of the ultrahigh-speed high-sensitivity CCD with a microlens array

    NASA Astrophysics Data System (ADS)

    Hayashida, T.,; Yonai, J.; Kitamura, K.; Arai, T.; Kurita, T.; Tanioka, K.; Maruyama, H.; Etoh, T. Goji; Kitagawa, S.; Hatade, K.; Yamaguchi, T.; Takeuchi, H.; Iida, K.

    2008-02-01

    We are advancing the development of ultrahigh-speed, high-sensitivity CCDs for broadcast use that are capable of capturing smooth slow-motion videos in vivid colors even where lighting is limited, such as at professional baseball games played at night. We have already developed a 300,000 pixel, ultrahigh-speed CCD, and a single CCD color camera that has been used for sports broadcasts and science programs using this CCD. However, there are cases where even higher sensitivity is required, such as when using a telephoto lens during a baseball broadcast or a high-magnification microscope during science programs. This paper provides a summary of our experimental development aimed at further increasing the sensitivity of CCDs using the light-collecting effects of a microlens array.

  6. High-resolution gravity and geoid models in Tahiti obtained from new airborne and land gravity observations: data fusion by spectral combination

    NASA Astrophysics Data System (ADS)

    Shih, Hsuan-Chang; Hwang, Cheinway; Barriot, Jean-Pierre; Mouyen, Maxime; Corréia, Pascal; Lequeux, Didier; Sichoix, Lydie

    2015-08-01

    For the first time, we carry out an airborne gravity survey and we collect new land gravity data over the islands of Tahiti and Moorea in French Polynesia located in the South Pacific Ocean. The new land gravity data are registered with GPS-derived coordinates, network-adjusted and outlier-edited, resulting in a mean standard error of 17 μGal. A crossover analysis of the airborne gravity data indicates a mean gravity accuracy of 1.7 mGal. New marine gravity around the two islands is derived from Geosat/GM, ERS-1/GM, Jason-1/GM, and Cryosat-2 altimeter data. A new 1-s digital topography model is constructed and is used to compute the topographic gravitational effects. To use EGM08 over Tahiti and Moorea, the optimal degree of spherical harmonic expansion is 1500. The fusion of the gravity datasets is made by the band-limited least-squares collocation, which best integrates datasets of different accuracies and spatial resolutions. The new high-resolution gravity and geoid grids are constructed on a 9-s grid. Assessments of the grids by measurements of ground gravity and geometric geoidal height result in RMS differences of 0.9 mGal and 0.4 cm, respectively. The geoid model allows 1-cm orthometric height determination by GPS and Lidar and yields a consistent height datum for Tahiti and Moorea. The new Bouguer anomalies show gravity highs and lows in the centers and land-sea zones of the two islands, allowing further studies of the density structure and volcanism in the region.

  7. Measurements of aerosol distributions and properties from Airborne High Spectral Resolution Lidar and DRAGON during the DISCOVER-AQ California Experiment (Invited)

    NASA Astrophysics Data System (ADS)

    Ferrare, R. A.; Burton, S. P.; Scarino, A. J.; Hostetler, C. A.; Hair, J. W.; Rogers, R. R.; Mueller, D.; Chemyakin, E.; Cook, A. L.; Harper, D. B.; Hare, R.; Holben, B. N.; Schafer, J.; Anderson, B. E.; Sawamura, P.

    2011-12-01

    The new NASA Langley Research Center airborne High Spectral Resolution Lidar-2 (HSRL-2) was deployed from the NASA Langley King Air aircraft for the DISCOVER-AQ (Deriving Information on Surface Conditions from COlumn and VERtically Resolved Observations Relevant to Air Quality) and DRAGON experiments that occurred over the San Joaquin Valley during January and February, 2013. The HSRL-2, which is the world's first airborne multiwavelength HSRL, measures aerosol extinction at 355 and 532 nm via the HSRL technique, as well as aerosol backscatter and depolarization at 355, 532, and 1064 nm. Additional HSRL-2 data products include aerosol type, mixed layer depth, and range-resolved aerosol microphysical parameters (e.g., effective radius, index of refraction, single scatter albedo, and concentration). During this mission, the King Air flights and HSRL-2 measurements were acquired over the DRAGON network and long-term AERONET sites and were closely coordinated with flights of the NASA P-3 aircraft that carried a suite of in situ aerosol instruments. In this presentation, we discuss how the HSRL-2 and DRAGON observations have been used to examine aerosol optical and microphysical properties as well as spatial and temporal variability. On some days, both HSRL-2 and DRAGON measurements indicated that coarse mode dust contributed a significant fraction of the aerosol optical thickness (AOT); in these cases, HSRL-2 measurements indicated that this depolarizing layer was located at the top of the boundary layer. We discuss differences in the aerosol properties between two episodes of high surface PM2.5 concentrations as revealed by the HSRL-2 and DRAGON measurements. Both the HSRL-2 and DRAGON measurements reveal considerable day-to-day spatial variability in the aerosol distributions across the valley. The HSRL-2 measurements also show variability in the daily evolution of the vertical distribution of aerosols.

  8. Measurements of aerosol distributions and properties from Airborne High Spectral Resolution Lidar and DRAGON during the DISCOVER-AQ California Experiment (Invited)

    NASA Astrophysics Data System (ADS)

    Ferrare, R. A.; Burton, S. P.; Scarino, A. J.; Hostetler, C. A.; Hair, J. W.; Rogers, R. R.; Mueller, D.; Chemyakin, E.; Cook, A. L.; Harper, D. B.; Hare, R.; Holben, B. N.; Schafer, J.; Anderson, B. E.; Sawamura, P.

    2013-12-01

    The new NASA Langley Research Center airborne High Spectral Resolution Lidar-2 (HSRL-2) was deployed from the NASA Langley King Air aircraft for the DISCOVER-AQ (Deriving Information on Surface Conditions from COlumn and VERtically Resolved Observations Relevant to Air Quality) and DRAGON experiments that occurred over the San Joaquin Valley during January and February, 2013. The HSRL-2, which is the world's first airborne multiwavelength HSRL, measures aerosol extinction at 355 and 532 nm via the HSRL technique, as well as aerosol backscatter and depolarization at 355, 532, and 1064 nm. Additional HSRL-2 data products include aerosol type, mixed layer depth, and range-resolved aerosol microphysical parameters (e.g., effective radius, index of refraction, single scatter albedo, and concentration). During this mission, the King Air flights and HSRL-2 measurements were acquired over the DRAGON network and long-term AERONET sites and were closely coordinated with flights of the NASA P-3 aircraft that carried a suite of in situ aerosol instruments. In this presentation, we discuss how the HSRL-2 and DRAGON observations have been used to examine aerosol optical and microphysical properties as well as spatial and temporal variability. On some days, both HSRL-2 and DRAGON measurements indicated that coarse mode dust contributed a significant fraction of the aerosol optical thickness (AOT); in these cases, HSRL-2 measurements indicated that this depolarizing layer was located at the top of the boundary layer. We discuss differences in the aerosol properties between two episodes of high surface PM2.5 concentrations as revealed by the HSRL-2 and DRAGON measurements. Both the HSRL-2 and DRAGON measurements reveal considerable day-to-day spatial variability in the aerosol distributions across the valley. The HSRL-2 measurements also show variability in the daily evolution of the vertical distribution of aerosols.

  9. The use of high resolution ground and airborne magnetic surveys to evaluate the geometry of hydrothermal alteration zones over volcanic provinces (Invited)

    NASA Astrophysics Data System (ADS)

    Bouligand, C.; Glen, J. M.

    2013-12-01

    Geophysical methods can provide critical constraints on the distribution and volume of hydrothermal alteration, important parameters in understanding the evolution of geothermal systems. Because hydrothermal alteration modifies the magnetic properties of the volcanic substratum, magnetic surveys can be used to provide constraints on the distribution of hydrothermal alteration at depth. Using Yellowstone caldera as an example, we show that both ground and airborne magnetic surveys can be used to map and assess the volume of hydrothermal alteration. Ground magnetic surveys over unaltered volcanic terranes display high-amplitude, short-wavelength anomalies, in contrast to smooth, subdued magnetic anomalies over volcanic substrata demagnetized by hydrothermal alteration. We use this contrast to map areas of hydrothermal alteration in detail. Inverse methods applied to high-resolution airborne and ground magnetic data can be used to create three-dimensional models of the distribution of magnetization and thus illuminate the geometry of hydrothermal alteration. Because of the non-uniqueness of potential fields, the construction of inverse models requires simplifying assumptions on the distribution of magnetization, knowledge of induced and remanent magnetization of fresh and altered geological units, and detailed geological and geophysical data. Within the three hydrothermal sites that we investigated in Yellowstone National Park, subdued short-wavelength signal indicates pervasive demagnetization (alteration) of the shallow substratum that extends over larger areas than initially mapped by geology. These data also reveal that the largest degree of demagnetization (alteration) and maximum thicknesses of demagnetized (altered) substratum, reaching a few hundred meters, are associated with hydrothermal vents and with superficial hydrothermal alteration. Our three dimensional models of magnetization provide estimates of the volume of buried hydrothermal alteration ranging

  10. Assessment of the CALIPSO Lidar 532 nm Attenuated Backscatter Calibration Using the NASA LaRC Airborne High Spectral Resolution Lidar

    NASA Technical Reports Server (NTRS)

    Rogers, Raymond R.; Hostetler, Chris A.; Hair, Johnathan W.; Ferrare, Richard A.; Liu, Zhaoyan; Obland, Michael D.; Harper, David B.; Cook, Anthony L.; Powell, Kathleen A.; Vaughan, Mark A.; Winker, David M.

    2011-01-01

    The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) spacecraft has provided global, high-resolution vertical profiles of aerosols and clouds since it became operational on 13 June 2006. On 14 June 2006, the NASA Langley Research Center (LaRC) High Spectral Resolution Lidar (HSRL) was deployed aboard the NASA Langley B-200 aircraft for the first of a series of 86 underflights of the CALIPSO satellite to provide validation measurements for the CALIOP data products. To better assess the range of conditions under which CALIOP data products are produced, these validation flights were conducted under both daytime and nighttime lighting conditions, in multiple seasons, and over a large range of latitudes and aerosol and cloud conditions. This paper presents a quantitative assessment of the CALIOP 532 nm calibration (through the 532 nm total attenuated backscatter) using an internally calibrated airborne HSRL underflight data and is the most extensive study of CALIOP 532 nm calibration. Results show that average HSRL and CALIOP 532 nm total attenuated backscatter agree on average within 2.7% +/- 2.1% (CALIOP lower) at night and within 2.9 % +/- 3.9% (CALIOP lower) during the day., demonstrating the accuracy of the CALIOP 532 nm calibration algorithms. Additionally, comparisons with HSRL show consistency of the CALIOP calibration before and after the laser switch in 2009 as well as improvements in the daytime version 3 calibration scheme compared with the version 2 calibration scheme. Potential systematic uncertainties in the methodology relevant to validating satellite lidar measurements with an airborne lidar system are discussed and found to be less than 3.7% for this validation effort with HSRL. Results from this study are also compared to those from prior assessments of CALIOP calibration and attenuated backscatter.

  11. Developing a semi/automated protocol to post-process large volume, High-resolution airborne thermal infrared (TIR) imagery for urban waste heat mapping

    NASA Astrophysics Data System (ADS)

    Rahman, Mir Mustafizur

    In collaboration with The City of Calgary 2011 Sustainability Direction and as part of the HEAT (Heat Energy Assessment Technologies) project, the focus of this research is to develop a semi/automated 'protocol' to post-process large volumes of high-resolution (H-res) airborne thermal infrared (TIR) imagery to enable accurate urban waste heat mapping. HEAT is a free GeoWeb service, designed to help Calgary residents improve their home energy efficiency by visualizing the amount and location of waste heat leaving their homes and communities, as easily as clicking on their house in Google Maps. HEAT metrics are derived from 43 flight lines of TABI-1800 (Thermal Airborne Broadband Imager) data acquired on May 13--14, 2012 at night (11:00 pm--5:00 am) over The City of Calgary, Alberta (˜825 km 2) at a 50 cm spatial resolution and 0.05°C thermal resolution. At present, the only way to generate a large area, high-spatial resolution TIR scene is to acquire separate airborne flight lines and mosaic them together. However, the ambient sensed temperature within, and between flight lines naturally changes during acquisition (due to varying atmospheric and local micro-climate conditions), resulting in mosaicked images with different temperatures for the same scene components (e.g. roads, buildings), and mosaic join-lines arbitrarily bisect many thousands of homes. In combination these effects result in reduced utility and classification accuracy including, poorly defined HEAT Metrics, inaccurate hotspot detection and raw imagery that are difficult to interpret. In an effort to minimize these effects, three new semi/automated post-processing algorithms (the protocol) are described, which are then used to generate a 43 flight line mosaic of TABI-1800 data from which accurate Calgary waste heat maps and HEAT metrics can be generated. These algorithms (presented as four peer-reviewed papers)---are: (a) Thermal Urban Road Normalization (TURN)---used to mitigate the microclimatic

  12. High-sensitivity and wide-directivity ultrasound detection using high Q polymer microring resonators

    PubMed Central

    Ling, Tao; Chen, Sung-Liang; Guo, L. Jay

    2011-01-01

    Small size ultrahigh Q polymer microrings working at near visible wavelength have been experimentally demonstrated as ultralow noise ultrasound detectors with wide directivity at high frequencies (>20 MHz). By combining a resist reflow and a low bias continuous etching and passivation process in mold fabrication, imprinted polymer microrings with drastically improved sidewall smoothness were obtained. An ultralow noise-equivalent pressure of 21.4 Pa over 1–75 MHz range has been achieved using a fabricated detector of 60 μm diameter. The device’s wide acceptance angle with high sensitivity considerably benefits ultrasound-related imaging. PMID:21673832

  13. High-sensitivity high-resolution dual-function signal and time digitizer

    NASA Astrophysics Data System (ADS)

    Sarwana, Saad; Gupta, Deepnarayan; Kirichenko, Alex F.; Oku, Takayuki; Otani, Chiko; Sato, Hiromi; Shimizu, Hirohiko M.

    2002-03-01

    We have developed a dual-function high sensitivity/high-resolution digitizer. It consists of a superconducting digital integrated circuit, which can operate both as a time-to-digital converter (TDC) and a flux counting analog-to-digital converter (ADC). The TDC has a 30 ps multihit time resolution. The ADC has been designed with a superconducting quantum interference device based detector for a 1 μA full scale range. This digitizer is extremely useful in many applications, e.g., for time-of-flight measurements, or as a radiation resistant, low-noise, low-power ADC for detector readout.

  14. Comparison of Aerosol Classification Results from Airborne High Spectral Resolution Lidar (HSRL) Measurements and the Calipso Vertical Feature Mask

    NASA Technical Reports Server (NTRS)

    Burton, S. P.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. W.; Rogers, R. R.; Obland, M. D.; Butler, C. F.; Cook, A. L.; Harper, D. B.; Froyd, K. D.; Omar, A.

    2012-01-01

    Knowledge of the vertical profile, composition, concentration, and size of aerosols is required for assessing the direct impact of aerosols on radiation, the indirect effects of aerosols on clouds and precipitation, and attributing these effects to natural and anthropogenic aerosols. Because anthropogenic aerosols are predominantly submicrometer, fine mode fraction (FMF) retrievals from satellite have been used as a tool for deriving anthropogenic aerosols. Although column and profile satellite retrievals of FMF have been performed over the ocean, such retrievals have not yet been been done over land. Consequently, uncertainty in satellite estimates of the anthropogenic component of the aerosol direct radiative forcing is greatest over land, due in large part to uncertainties in the FMF. Satellite measurements have been used to detect and evaluate aerosol impacts on clouds; however, such efforts have been hampered by the difficulty in retrieving vertically-resolved cloud condensation nuclei (CCN) concentration, which is the most direct parameter linking aerosol and clouds. Recent studies have shown correlations between average satellite derived column aerosol optical thickness (AOT) and in situ measured CCN. However, these same studies, as well as others that use detailed airborne in situ measurements have noted that vertical variability of the aerosol distribution, impacts of relative humidity, and the presence of coarse mode aerosols such as dust introduce large uncertainties in such relations.

  15. FIELD ACTIVITIES AND PRELIMINARY RESULTS FROM THE INVESTIGATION OF WESTERN AIRBORNE CONTAMINANTS IN TWO HIGH ELEVATION WATERSHEDS OF ROCKY MOUNTAIN NATIONAL PARK

    EPA Science Inventory

    The National Park Service initiated the Western Airborne Contaminants Assessment Project (WACAP) in 2002 to determine if airborne contaminants from long-range transport and/or regional sources are having an impact on remote western ecosystems, including AK. Rocky Mountain Nation...

  16. Further study on highly sensitive AMS measurement of 53Mn

    NASA Astrophysics Data System (ADS)

    Kejun, Dong; Hao, Hu; Xianggao, Wang; Chaoli, Li; Ming, He; Zhenyu, Li; Shaoyong, Wu; Jiancheng, Liu; Guowen, Zheng; Heng, Li; Zhigang, Chen; Guangshan, Liu; Jian, Yuan; Shan, Jiang

    2012-08-01

    The AMS facility at China Institute of Atomic Energy has been equipped with a ΔE-Q3D detection system for the measurements of 53Mn. While the sample material of MnO2 and the extraction ions of MnO- were used previously in AMS measurement of 53Mn with fairly good results, a method has recently been developed with the extraction of MnF- from ion source using MnF2 and MnO2 + PbF2 as sample materials. As a result, a sensitivity of 10-14 (53Mn/Mn) has been achieved. Compared with the original MnO-/MnO2 approach, the method of MnF- extraction, combined with ΔE-Q3D detection technique, demonstrated an improved sensitivity for AMS measurement of 53Mn.

  17. A High Sensitivity Laser-Pumped Cesium Magnetometer

    NASA Astrophysics Data System (ADS)

    Huang, Kai-Kai; Li, Nan; Lu, Xuan-Hui

    2012-10-01

    An atomic magnetometer based on optically detected magnetic resonance is investigated and demonstrated experimentally. We build an 894 nm external cavity diode laser which is frequency locked to the F = 4 → F' = 3 transition of Cs D1 line with DAVLL spectroscopy. With the phase-locked loop, the frequency of the rf coils is actively locked to the Larmor frequency and the magnetometer tracks the magnetic field variations in a phase coherent manner. An ultimate sensitivity of 19 fT/Hz1/2 and an intrinsic sensitivity of 8.6 pT/Hz1/2 in the magnetic environment which is close to geomagnetic field have been achieved with the spatial resolution smaller than 2 cm.

  18. Highly sensitive BTX detection using surface functionalized QCM sensor

    NASA Astrophysics Data System (ADS)

    Bozkurt, Asuman Aşıkoǧlu; Özdemir, Okan; Altındal, Ahmet

    2016-03-01

    A novel organic compound was designed and successfully synthesized for the fabrication of QCM based sensors to detect the low concentrations of BTX gases in indoor air. The effect of the long-range electron orbital delocalization on the BTX vapour sensing properties of azo-bridged Pcs based chemiresistor-type sensors have also been investigated in this work. The sensing behaviour of the film for the online detection of volatile organic solvent vapors was investigated by utilizing an AT-cut quartz crystal resonator. It was observed that the adsorption of the target molecules on the coating surface cause a reversible negative frequency shift of the resonator. Thus, a variety of solvent vapors can be detected by using the phthalocyanine film as sensitive coating, with sensitivity in the ppm range and response times in the order of several seconds depending on the molecular structure of the organic solvent.

  19. High sensitivity gas sensor based on high-Q suspended polymer photonic crystal nanocavity

    SciTech Connect

    Clevenson, Hannah Desjardins, Pierre; Gan, Xuetao; Englund, Dirk

    2014-06-16

    We present high-sensitivity, multi-use optical gas sensors based on a one-dimensional photonic crystal cavity. These devices are implemented in versatile, flexible polymer materials which swell when in contact with a target gas, causing a measurable cavity length change. This change causes a shift in the cavity resonance, allowing precision measurements of gas concentration. We demonstrate suspended polymer nanocavity sensors and the recovery of sensors after the removal of stimulant gas from the system. With a measured quality factor exceeding 10{sup 4}, we show measurements of gas concentration as low as 600 parts per million (ppm) and an experimental sensitivity of 10 ppm; furthermore, we predict detection levels in the parts-per-billion range for a variety of gases.

  20. Genetic influence on brain catecholamines: high brain norepinephrine in salt-sensitive rats

    SciTech Connect

    Iwai, J; Friedman, R; Tassinari, L

    1980-01-01

    Rats genetically sensitive to salt-induced hypertension evinced higher levels of plasma norepinephrine and epinephrine than rats genetically resistant to hypertension. The hypertension-sensitive rats showed higher hypothalamic norepinephrine and lower epinephrine than resistant rats. In response to a high salt diet, brain stem norepinephrine increased in sensitive rats while resistant rats exhibited a decrease on the same diet.

  1. Analysis of Cyberbullying Sensitivity Levels of High School Students and Their Perceived Social Support Levels

    ERIC Educational Resources Information Center

    Akturk, Ahmet Oguz

    2015-01-01

    Purpose: The purpose of this paper is to determine the cyberbullying sensitivity levels of high school students and their perceived social supports levels, and analyze the variables that predict cyberbullying sensitivity. In addition, whether cyberbullying sensitivity levels and social support levels differed according to gender was also…

  2. High Resolution, High Sensitivity Detectors for Molecular Imaging of Small Animals and Tumor Detection

    NASA Astrophysics Data System (ADS)

    Magliozzi, M. L.; Cisbani, E.; Colilli, S.; Cusanno, F.; Fratoni, R.; Garibaldi, F.; Giuliani, F.; Gricia, M.; Lo Meo, S.; Lucentini, M.; Santavenere, F.; Veneroni, P.; Schillaci, O.; Simonetti, G.; Majewsky, S.; Cinti, M. N.; de Vincentis, G.; Pani, R.; Pellegrini, R.; Scopinaro, F.

    2006-04-01

    Imaging techniques with radionuclides provide very sensitive measures of a wide range of specific processes underying disease in the body. Detection of very small tumors with high specificity is therefore possible but the tecnique requires both high spatial resolution and high sensitivity. We present the first simulations, performed by means of GEANT4 code, of breast tumors, imaged by different configurations of a compact discrete gamma camera, in order to optimize the performances of dedicated detectors for these tasks. Simulated planar images from 6 to 10 mm diameter tumors, placed at 5 mm from the collimator, were generated for NaI scintillator pixel sizes of 1.0×1.0 and 1.2×1.2 mm2, hexagonal hole Pb collimators with hole size of 1.5 and 1.9 mm. The generated photons have been sampled by two modelled Hamamatsu H8500 and H9500 PMT. Tumor to background uptake ratio from 1:6 to 1:12 has been considered. The preliminary results in terms of spatial resolution and SNR show a slightly better performance of the high efficiency collimator, larger crystal size and H9500 combination.

  3. JAFFA: High sensitivity transcriptome-focused fusion gene detection.

    PubMed

    Davidson, Nadia M; Majewski, Ian J; Oshlack, Alicia

    2015-01-01

    Genomic instability is a hallmark of cancer and, as such, structural alterations and fusion genes are common events in the cancer landscape. RNA sequencing (RNA-Seq) is a powerful method for profiling cancers, but current methods for identifying fusion genes are optimised for short reads. JAFFA (https://github.com/Oshlack/JAFFA/wiki) is a sensitive fusion detection method that outperforms other methods with reads of 100 bp or greater. JAFFA compares a cancer transcriptome to the reference transcriptome, rather than the genome, where the cancer transcriptome is inferred using long reads directly or by de novo assembling short reads. PMID:26019724

  4. High-sensitivity capillary and microchip electrophoresis using electrokinetic supercharging.

    PubMed

    Dawod, Mohamed; Chung, Doo Soo

    2011-10-01

    Electrokinetic supercharging (EKS) is considered as one of the most powerful online preconcentration techniques in electrophoresis. It combines the efficient preconcentration power of field-amplified sample injection and the exceptional selective nature of transient isotachophoresis. It has a wide range of applications to different types of analytes ranging from small ions to large proteins and DNA fragments. This comprehensive review--up to date--provides listing for all the works, developments, and advances in EKS. The review will pay particular attention to innovations, new methodologies for manipulation, challenges for improving the detection sensitivity, and various applications of EKS in capillaries and microchips. PMID:21793208

  5. Super LOTIS a high sensitive optical counterpart search experiment

    SciTech Connect

    Park, H.S., Ables, E.; Band, D.L

    1997-11-17

    We are constructing a 0.6 meter telescope system to search for early time gamma-ray burst (GRB) optical counterparts. Super-LOTIS (Super-Livermore Optical Transient Imaging System) is an automated telescope system that has a 0.8 x 0.8{degree} field-of-view, is sensitive to M{sub v} {approximately} 19 and responds to a burst trigger within 5 min. This telescope will record images of the gamma-ray burst coordinates that is given by the GCN (GRB Coordinate Network). A measurement of GRB light curves at early times will greatly enhance our understanding of GRB physics.

  6. A low-power, high-sensitivity micromachined optical magnetometer

    NASA Astrophysics Data System (ADS)

    Mhaskar, R.; Knappe, S.; Kitching, J.

    2012-12-01

    We demonstrate an optical magnetometer based on a microfabricated 87Rb vapor cell in a micromachined silicon sensor head. The alkali atom density in the vapor cell is increased by heating the cell with light brought to the sensor through an optical fiber, and absorbed by colored filters attached to the cell windows. A second fiber-optically coupled beam optically pumps and interrogates the atoms. The magnetometer operates on 140 mW of heating power and achieves a sensitivity below 20 fT/√Hz throughout most of the frequency band from 15 Hz to 100 Hz. Such a sensor can measure magnetic fields from the human heart and brain.

  7. An overview of a highly versatile forward and stable inverse algorithm for airborne, ground-based and borehole electromagnetic and electric data

    NASA Astrophysics Data System (ADS)

    Auken, Esben; Christiansen, Anders Vest; Kirkegaard, Casper; Fiandaca, Gianluca; Schamper, Cyril; Behroozmand, Ahmad Ali; Binley, Andrew; Nielsen, Emil; Effersø, Flemming; Christensen, Niels Bøie; Sørensen, Kurt; Foged, Nikolaj; Vignoli, Giulio

    2015-07-01

    We present an overview of a mature, robust and general algorithm providing a single framework for the inversion of most electromagnetic and electrical data types and instrument geometries. The implementation mainly uses a 1D earth formulation for electromagnetics and magnetic resonance sounding (MRS) responses, while the geoelectric responses are both 1D and 2D and the sheet's response models a 3D conductive sheet in a conductive host with an overburden of varying thickness and resistivity. In all cases, the focus is placed on delivering full system forward modelling across all supported types of data. Our implementation is modular, meaning that the bulk of the algorithm is independent of data type, making it easy to add support for new types. Having implemented forward response routines and file I/O for a given data type provides access to a robust and general inversion engine. This engine includes support for mixed data types, arbitrary model parameter constraints, integration of prior information and calculation of both model parameter sensitivity analysis and depth of investigation. We present a review of our implementation and methodology and show four different examples illustrating the versatility of the algorithm. The first example is a laterally constrained joint inversion (LCI) of surface time domain induced polarisation (TDIP) data and borehole TDIP data. The second example shows a spatially constrained inversion (SCI) of airborne transient electromagnetic (AEM) data. The third example is an inversion and sensitivity analysis of MRS data, where the electrical structure is constrained with AEM data. The fourth example is an inversion of AEM data, where the model is described by a 3D sheet in a layered conductive host.

  8. Highly Sensitive Immunochromatographic Identification of Tetracycline Antibiotics in Milk

    PubMed Central

    Taranova, N. A.; Kruhlik, A. S.; Zvereva, E. A.; Shmanai, V. V.; Vashkevich, I. I.; Semyonov, D. A.; Eremin, S. A.; Zherdev, A. V.; Dzantiev, B. B.

    2015-01-01

    A rapid immunochromatographic assay was developed for the control of tetracycline (TC). The assay is based on the competition between immobilized TC-protein conjugate and TC in a tested sample for binding with polyclonal anti-TC antibodies conjugated to colloidal gold during the flow of the sample along a membrane strip with immobilized reactants. Conjugation of colloidal gold and the total immunoglobulin (IgG) fraction of polyclonal antibodies was used to increase the assay sensitivity to ensure low content of specific antibodies in the conjugate. This allowed effective inhibition of free TC and conjugate binding in the strip test zone. Photometric marker registration allows control of the reduction of binding, thereby enhancing detection sensitivity. The proposed assay allows TC to be detected at concentrations up to 20 ng/mL, exceeding the limit of detection of the known analogues, in a wide working range (more than two orders) of 60 pg/mL to 10 ng/mL, ensured through the use of polyclonal antibodies. The assay time is 10 min. The efficiency of the designed assay is shown to identify TC in milk; the degree of recovery of TC ranges from 90 to 112%. The precision of the concentrations measurements was no more than 10%. PMID:26689537

  9. A protein multiplex microarray substrate with high sensitivity and specificity

    PubMed Central

    Fici, Dolores A.; McCormick, William; Brown, David W.; Herrmann, John E.; Kumar, Vikram; Awdeh, Zuheir L.

    2010-01-01

    The problems that have been associated with protein multiplex microarray immunoassay substrates and existing technology platforms include: binding, sensitivity, a low signal to noise ratio, target immobilization and the optimal simultaneous detection of diverse protein targets. Current commercial substrates for planar multiplex microarrays rely on protein attachment chemistries that range from covalent attachment to affinity ligand capture, to simple adsorption. In this pilot study, experimental performance parameters for direct monoclonal mouse IgG detection were compared for available two and three dimensional slide surface coatings with a new colloidal nitrocellulose substrate. New technology multiplex microarrays were also developed and evaluated for the detection of pathogen specific antibodies in human serum and the direct detection of enteric viral antigens. Data supports the nitrocellulose colloid as an effective reagent with the capacity to immobilize sufficient diverse protein target quantities for increased specificory signal without compromising authentic protein structure. The nitrocellulose colloid reagent is compatible with the array spotters and scanners routinely used for microarray preparation and processing. More importantly, as an alternate to fluorescence, colorimetric chemistries may be used for specific and sensitive protein target detection. The advantages of the nitrocellulose colloid platform indicate that this technology may be a valuable tool for the further development and expansion of multiplex microarray immunoassays in both the clinical and research laborat environment. PMID:20974147

  10. Nanostructured photoelectrochemical biosensor for highly sensitive detection of organophosphorous pesticides.

    PubMed

    Li, Xinyu; Zheng, Zhaozhu; Liu, Xuefeng; Zhao, Shenlong; Liu, Shaoqin

    2015-02-15

    A sensitive photoelectrochemical (PEC) biosensor for detection of organophosphorus pesticides (OPs) using the nanocomposite of CdSe@ZnS quantum dots (QDs) and graphene deposited on the ITO coated glass electrode as a photoactive electrode is presented. The integration of CdSe@ZnS/graphene nanocomposite with biomolecules acetylcholinesterase (AChE) as a biorecognition element yields a novel biosensing platform. Under visible light irradiation, the AChE-CdSe@ZnS/graphene nanocomposite can generate a stable photocurrent and the photocurrent is found to be inversely dependent on the concentration of OPs. Under the optimal experimental conditions, the photocurrents were proportional to the logarithm of paraoxon and dichlorvos within the concentration range of 10(-12)-10(-6) M. The detection limits (LOD) of the proposed biosensor for paraoxon and dichlorvos are as low as 10(-14) M and 10(-12) M. The photoelectrochemical biosensor shows good sensitivity, reproducibility, stability, and could be successfully applied to detection of OPs in real fruit samples. PMID:25173731

  11. Monitoring of viable airborne SARS virus in ambient air

    NASA Astrophysics Data System (ADS)

    Agranovski, Igor E.; Safatov, Alexander S.; Pyankov, Oleg V.; Sergeev, Alexander N.; Agafonov, Alexander P.; Ignatiev, Georgy M.; Ryabchikova, Elena I.; Borodulin, Alexander I.; Sergeev, Artemii A.; Doerr, Hans W.; Rabenau, Holger F.; Agranovski, Victoria

    Due to recent SARS related issues (Science 300 (5624) 1394; Nature 423 (2003) 240; Science 300 (5627) 1966), the development of reliable airborne virus monitoring procedures has become galvanized by an exceptional sense of urgency and is presently in a high demand (In: Cox, C.S., Wathers, C.M. (Eds.), Bioaerosols Handbook, Lewis Publishers, Boca Raton, FL, 1995, pp. 247-267). Based on engineering control method (Aerosol Science and Technology 31 (1999) 249; 35 (2001) 852), which was previously applied to the removal of particles from gas carriers, a new personal bioaerosol sampler has been developed. Contaminated air is bubbled through porous medium submerged into liquid and subsequently split into multitude of very small bubbles. The particulates are scavenged by these bubbles, and, thus, effectively removed. The current study explores its feasibility for monitoring of viable airborne SARS virus. It was found that the natural decay of such virus in the collection fluid was around 0.75 and 1.76 lg during 2 and 4 h of continuous operation, respectively. Theoretical microbial recovery rates of higher than 55 and 19% were calculated for 1 and 2 h of operation, respectively. Thus, the new sampling method of direct non-violent collection of viable airborne SARS virus into the appropriate liquid environment was found suitable for monitoring of such stress sensitive virus.

  12. High precision, high sensitivity distributed displacement and temperature measurements using OFDR-based phase tracking

    NASA Astrophysics Data System (ADS)

    Gifford, Dawn K.; Froggatt, Mark E.; Kreger, Stephen T.

    2011-05-01

    Optical Frequency Domain Reflectometry is used to measure distributed displacement and temperature change with very high sensitivity and precision by measuring the phase change of an optical fiber sensor as a function of distance with high spatial resolution and accuracy. A fiber containing semi-continuous Bragg gratings was used as the sensor. The effective length change, or displacement, in the fiber caused by small temperature changes was measured as a function of distance with a precision of 2.4 nm and a spatial resolution of 1.5 mm. The temperature changes calculated from this displacement were measured with precision of 0.001 C with an effective sensor gauge length of 12 cm. These results demonstrate that the method employed of continuously tracking the phase change along the length of the fiber sensor enables high resolution distributed measurements that can be used to detect very small displacements, temperature changes, or strains.

  13. High temperature probe sensor with high sensitivity based on Michelson interferometer

    NASA Astrophysics Data System (ADS)

    Zhao, Na; Fu, Haiwei; Shao, Min; Yan, Xu; Li, Huidong; Liu, Qinpeng; Gao, Hong; Liu, Yinggang; Qiao, Xueguang

    2015-05-01

    A novel Michelson interferometer based on a bi-taper is achieved. Such a device is fabricated by splicing a section of thin core fiber (TCF) at one end of single-mode fiber (SMF). Due to the fiber bi-taper at the splicing point of SMF and TCF, the light is coupled into the fiber core and cladding from lead in fiber core. The light will be reflected at the end of the fiber and then will be recoupled back into the lead out fiber core by the fiber bi-taper. While the light returns back to the lead out fiber, the intermodal interference will occur for the optical path difference between core mode and cladding mode. A high temperature sensitivity of 0.140 nm/°C is achieved from 30 to 800 °C, and the linearity is 99.9%. The configuration features the advantages of easy fabrication, a compact size, high sensitivity, wide sensing range and high mechanical strength, making it a good candidate for distant temperature sensing and oil prospecting.

  14. High-sensitivity, high-selectivity detection of chemical warfare agents

    NASA Astrophysics Data System (ADS)

    Pushkarsky, Michael B.; Webber, Michael E.; Macdonald, Tyson; Patel, C. Kumar N.

    2006-01-01

    We report high-sensitivity detection of chemical warfare agents (nerve gases) with very low probability of false positives (PFP). We demonstrate a detection threshold of 1.2ppb (7.7μg/m3 equivalent of Sarin) with a PFP of <1:106 in the presence of many interfering gases present in an urban environment through the detection of diisopropyl methylphosphonate, an accepted relatively harmless surrogate for the nerve agents. For the current measurement time of ˜60s, a PFP of 1:106 corresponds to one false alarm approximately every 23months. The demonstrated performance satisfies most current homeland and military security requirements.

  15. Ultra-high sensitive and high resolution optical coherence tomography using a laser induced electromagnetic dipole

    NASA Astrophysics Data System (ADS)

    Kuroda, Hiroto; Baba, Motoyoshi; Suzuki, Masayuki; Yoneya, Shin

    2013-09-01

    Utilizing an optical coherence tomography measurement, we have developed a technique that actively uses a dielectric response due to an induced dipole moment caused by a mode-locked pulsed laser light source. Irradiated laser light in the material induces a photo-induced electric dipole resulting in a refractive index change for its strong electric field. Using this technique, we obtained a highly sensitive fundus retina tomogram of a human eye in vivo with a resolution of 1.3 μm by single scanning for 20 ms using 8 fs mode-locked pulse laser light with a 350 nm spread spectrum.

  16. Satellite and airborne IR sensor validation by an airborne interferometer

    SciTech Connect

    Gumley, L.E.; Delst, P.F. van; Moeller, C.C.

    1996-11-01

    The validation of in-orbit longwave IR radiances from the GOES-8 Sounder and inflight longwave IR radiances from the MODIS Airborne Simulator (MAS) is described. The reference used is the airborne University of Wisconsin High Resolution Interferometer Sounder (HIS). The calibration of each sensor is described. Data collected during the Ocean Temperature Interferometric Survey (OTIS) experiment in January 1995 is used in the comparison between sensors. Detailed forward calculations of at-sensor radiance are used to account for the difference in GOES-8 and HIS altitude and viewing geometry. MAS radiances and spectrally averaged HIS radiances are compared directly. Differences between GOES-8 and HIS brightness temperatures, and GOES-8 and MAS brightness temperatures, are found to be with 1.0 K for the majority of longwave channels examined. The same validation approach will be used for future sensors such as the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Atmospheric Infrared Sounder (AIRS). 11 refs., 2 figs., 4 tabs.

  17. Novel Characteristics of Photodamage to PSII in a High-Light-Sensitive Symbiodinium Phylotype.

    PubMed

    Karim, Widiastuti; Seidi, Azadeh; Hill, Ross; Chow, Wah S; Minagawa, Jun; Hidaka, Michio; Takahashi, Shunichi

    2015-06-01

    Dinoflagellates from the genus Symbiodinium form symbiotic relationships with many marine invertebrates, including reef-building corals. Symbiodinium is genetically diverse, and acquiring suitable Symbiodinium phylotypes is crucial for the host to survive in habitat environments, such as high-light conditions. The sensitivity of Symbiodinium to high light differs among Symbiodinium phylotypes, but the mechanism that controls light sensitivity has not yet been fully resolved. In the present study using high-light-tolerant and -sensitive Symbiodinium phylotypes, we examined what determines sensitivity to high light. In growth experiments under different light intensities, Symbiodinium CS-164 (clade B1) and CCMP2459 (clade B2) were identified as high-light-tolerant and -sensitive phylotypes, respectively. Measurements of the maximum quantum yield of photosystem II (PSII) and the maximum photosynthetic oxygen production rate after high-light exposure demonstrated that CCMP2459 is more sensitive to photoinhibition of PSII than CS-164, and tends to lose maximum photosynthetic activity faster. Measurement of photodamage to PSII under light of different wavelength ranges demonstrated that PSII in both Symbiodinium phylotypes was significantly more sensitive to photodamage under shorter wavelength regions of light spectra (<470 nm). Importantly, PSII in CCMP2459, but not CS-164, was also sensitive to photodamage under the regions of light spectra around 470-550 and 630-710 nm, where photosynthetic antenna proteins of Symbiodinium have light absorption peaks. This finding indicates that the high-light-sensitive CCMP2459 has an extra component of photodamage to PSII, resulting in higher sensitivity to high light. Our results demonstrate that sensitivity of PSII to photodamage differs among Symbiodinium phylotypes and this determines their sensitivity to high light. PMID:25759327

  18. A new compact, high sensitivity neutron imaging system

    SciTech Connect

    Caillaud, T.; Landoas, O.; Briat, M.; Rosse, B.; Thfoin, I.; Philippe, F.; Casner, A.; Bourgade, J. L.; Disdier, L.; Glebov, V. Yu.; Marshall, F. J.; Sangster, T. C.; Park, H. S.; Robey, H. F.; Amendt, P.

    2012-10-15

    We have developed a new small neutron imaging system (SNIS) diagnostic for the OMEGA laser facility. The SNIS uses a penumbral coded aperture and has been designed to record images from low yield (10{sup 9}-10{sup 10} neutrons) implosions such as those using deuterium as the fuel. This camera was tested at OMEGA in 2009 on a rugby hohlraum energetics experiment where it recorded an image at a yield of 1.4 Multiplication-Sign 10{sup 10}. The resolution of this image was 54 {mu}m and the camera was located only 4 meters from target chamber centre. We recently improved the instrument by adding a cooled CCD camera. The sensitivity of the new camera has been fully characterized using a linear accelerator and a {sup 60}Co {gamma}-ray source. The calibration showed that the signal-to-noise ratio could be improved by using raw binning detection.

  19. Development of highly sensitive sensor system for methane utilizing cataluminescence.

    PubMed

    Gong, Gu; Zhu, Hua

    2016-02-01

    A gaseous sensor system was developed for the detection of methane based on its cataluminescence emission. Cataluminescence characteristics and optimal conditions were studied in detail under optimized experimental conditions. Results showed that the methane cataluminescence sensor system could cover a linear detection range from 10 to 5800 ppm (R = 0.9963, n = 7) and the detection limit was about 7 ppm (S/N = 3), which was below the standard permitted concentration. Moreover, a linear discriminant analysis method was used to test the recognizable performance of the methane sensor. It was found that methane, ethane, propane and pentane could be distinguished clearly. Its methane sensing properties, including improved sensitivity, selectivity, stability and recognition demonstrated the TiO2/SnO2 materials to be promising candidates for constructing a cataluminescence-based gas sensor that could be used for detecting explosive gas contaminants. PMID:26014851

  20. Genome-wide synteny through highly sensitive sequence alignment: Satsuma

    PubMed Central

    Grabherr, Manfred G.; Russell, Pamela; Meyer, Miriah; Mauceli, Evan; Alföldi, Jessica; Di Palma, Federica; Lindblad-Toh, Kerstin

    2010-01-01

    Motivation: Comparative genomics heavily relies on alignments of large and often complex DNA sequences. From an engineering perspective, the problem here is to provide maximum sensitivity (to find all there is to find), specificity (to only find real homology) and speed (to accommodate the billions of base pairs of vertebrate genomes). Results: Satsuma addresses all three issues through novel strategies: (i) cross-correlation, implemented via fast Fourier transform; (ii) a match scoring scheme that eliminates almost all false hits; and (iii) an asynchronous ‘battleship’-like search that allows for aligning two entire fish genomes (470 and 217 Mb) in 120 CPU hours using 15 processors on a single machine. Availability: Satsuma is part of the Spines software package, implemented in C++ on Linux. The latest version of Spines can be freely downloaded under the LGPL license from http://www.broadinstitute.org/science/programs/genome-biology/spines/ Contact: grabherr@broadinstitute.org PMID:20208069

  1. Particles and microfluidics merged: perspectives of highly sensitive diagnostic detection

    PubMed Central

    Bale, Shyam Sundhar; Bhushan, Abhinav; Shen, Keyue; Seker, Erkin; Polyak, Boris

    2014-01-01

    There is a growing need for diagnostic technologies that provide laboratories with solutions that improve quality, enhance laboratory system productivity, and provide accurate detection of a broad range of infectious diseases and cancers. Recent advances in micro- and nanoscience and engineering, in particular in the areas of particles and microfluidic technologies, have advanced the “lab-on-a-chip” concept towards the development of a new generation of point-of-care diagnostic devices that could significantly enhance test sensitivity and speed. In this review, we will discuss many of the recent advances in microfluidics and particle technologies with an eye towards merging these two technologies for application in medical diagnostics. Although the potential diagnostic applications are virtually unlimited, the most important applications are foreseen in the areas of biomarker research, cancer diagnosis, and detection of infectious microorganisms. PMID:25378716

  2. Highly sensitive detection of nitroaromatic explosives at discrete nanowire arrays.

    PubMed

    Barry, Sean; Dawson, Karen; Correa, Elon; Goodacre, Royston; O'Riordan, Alan

    2013-01-01

    We show a photolithography technique that permits gold nanowire array electrodes to be routinely fabricated at reasonable cost. Nanowire electrode arrays offer the potential for enhancements in electroanalysis such as increased signal-to-noise ratio and increased sensitivity while also allowing quantitative detection at much lower concentrations. We explore application of nanowire array electrodes to the detection of different nitroaromatic species. Characteristic reduction peaks of nitro groups are not observed at nanowire array electrodes using sweep voltammetric methods. By contrast, clear and well-defined reduction peaks are resolved using potential step square wave voltammetry. A Principle Component Analysis technique is employed to discriminate between nitroaromatic species including structural isomers of DNT. The analysis indicates that all compounds are successfully discriminated by unsupervised cluster analysis. Finally, the magnitude of the reduction peak at -671 mV for different concentrations of TNT exhibited excellent linearity with increasing concentrations enabling sub-150 ng mL(-1) limits of detection. PMID:24466670

  3. High sensitivity infrared 10.6 micrometer heterodyne receiver development

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The results are presented for a study on the design of an infrared 10.6-micrometer quantum-noise-limited optical receiver subsystem. Performance measurements of the HgCdTe photomixer preamplifier combination were carried out for photomixer temperatures up to 152 K and a photomixer frequency response of up to 420 MHz was obtained. Results of temperature and bias cycling of HgCdTe photomixers are reported. Design considerations for an operational 10.6 micrometer heterodyne receiver are presented. These consist of design data on required laser LO illumination, heat load levels for photomixer cooler, photomixer uniformity and the effects of photomixer impedance match on receiver sensitivity. Analysis and measurements of 10.6 micrometer heterodyne detection in an extrinsic photoconductive (p-type) HgCdTe photomixer are also presented.

  4. Highly sensitive humidity sensing properties of carbon quantum dots films

    SciTech Connect

    Zhang, Xing; Ming, Hai; Liu, Ruihua; Han, Xiao; Kang, Zhenhui; Liu, Yang; Zhang, Yonglai

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ► A humidity sensing device was fabricated based on carbon quantum dots (CQDs) films. ► The conductivity of the CQDs films shows a linear and rapid response to atmosphere humidity. ► The humidity sensing property was due to the hydrogen bonds between the functional groups on CQDs. -- Abstract: We reported the fabrication of a humidity sensing device based on carbon quantum dots (CQDs) film. The conductivity of the CQDs film has a linear and rapid response to relative humidity, providing the opportunity for the fabrication of humidity sensing devices. The mechanism of our humidity sensor was proposed to be the formation of hydrogen bonds between carbon quantum dots and water molecules in the humidity environment, which significantly promote the electrons migration. In a control experiment, this hypothesis was confirmed by comparing the humidity sensitivity of candle soot (i.e. carbon nanoparticles) with and without oxygen containing groups on the surfaces.

  5. Metallophthalocyanines as triplet sensitizers for highly efficient photon upconversion based on sensitized triplet-triplet annihilation.

    PubMed

    Han, J L; You, J; Yonemura, H; Yamada, S; Wang, S R; Li, X G

    2016-08-01

    Soluble palladium and platinum phthalocyanines with coumarin moieties were synthesized with Q bands in the red and near-IR regions, in which the molar extinction coefficients were up to 1.01 × 10(5) cm(-1) mol(-1). These metallophthalocyanines were coupled with rubrene and applied in photon upconversion systems based on triplet-triplet annihilation. The highest upconversion efficiency of the palladium phthalocyanine was 5.6%, which is higher than that of the platinum phthalocyanine-rubrene system. The larger molar extinction coefficient resulted in high upconversion capability (>10(5) cm(-1) mol(-1)) and low saturation incident power (<20 mW cm(-2)). PMID:27431880

  6. High fat diet-fed obese rats are highly sensitive to doxorubicin-induced cardiotoxicity

    SciTech Connect

    Mitra, Mayurranjan S.; Donthamsetty, Shashikiran; White, Brent; Mehendale, Harihara M.

    2008-09-15

    Often, chemotherapy by doxorubicin (Adriamycin) is limited due to life threatening cardiotoxicity in patients during and posttherapy. Recently, we have shown that moderate diet restriction remarkably protects against doxorubicin-induced cardiotoxicity. This cardioprotection is accompanied by decreased cardiac oxidative stress and triglycerides and increased cardiac fatty-acid oxidation, ATP synthesis, and upregulated JAK/STAT3 pathway. In the current study, we investigated whether a physiological intervention by feeding 40% high fat diet (HFD), which induces obesity in male Sprague-Dawley rats (250-275 g), sensitizes to doxorubicin-induced cardiotoxicity. A LD{sub 10} dose (8 mg doxorubicin/kg, ip) administered on day 43 of the HFD feeding regimen led to higher cardiotoxicity, cardiac dysfunction, lipid peroxidation, and 80% mortality in the obese (OB) rats in the absence of any significant renal or hepatic toxicity. Doxorubicin toxicokinetics studies revealed no change in accumulation of doxorubicin and doxorubicinol (toxic metabolite) in the normal diet-fed (ND) and OB hearts. Mechanistic studies revealed that OB rats are sensitized due to: (1) higher oxyradical stress leading to upregulation of uncoupling proteins 2 and 3, (2) downregulation of cardiac peroxisome proliferators activated receptor-{alpha}, (3) decreased plasma adiponectin levels, (4) decreased cardiac fatty-acid oxidation (666.9 {+-} 14.0 nmol/min/g heart in ND versus 400.2 {+-} 11.8 nmol/min/g heart in OB), (5) decreased mitochondrial AMP-{alpha}2 protein kinase, and (6) 86% drop in cardiac ATP levels accompanied by decreased ATP/ADP ratio after doxorubicin administration. Decreased cardiac erythropoietin and increased SOCS3 further downregulated the cardioprotective JAK/STAT3 pathway. In conclusion, HFD-induced obese rats are highly sensitized to doxorubicin-induced cardiotoxicity by substantially downregulating cardiac mitochondrial ATP generation, increasing oxidative stress and downregulating

  7. Can airborne fungal allergens pass through an air-conditioning system. [Aspergillus fumigatus

    SciTech Connect

    Elixmann, J.H. ); Linskens, H.F.; Schata, M.; Jorde, W. )

    1989-01-01

    Fungal spores, an important fraction of aeroplankton particles, can be filtered in an air-conditioning system, resulting in a drastic reduction of the spore count in the air-conditioned rooms. Nevertheless, using the EISA inhibition test against Aspergillus fumigatus, it was found that air samples from air-conditioned rooms show inhibition of the serum activity of a highly sensitized patient. There is evidence that airborne allergens can pass both coarse and fine filters of an air-conditioning system.

  8. High-sensitivity in situ QCLAS-based ammonia concentration sensor for high-temperature applications

    NASA Astrophysics Data System (ADS)

    Peng, W. Y.; Sur, R.; Strand, C. L.; Spearrin, R. M.; Jeffries, J. B.; Hanson, R. K.

    2016-07-01

    A novel quantum cascade laser (QCL) absorption sensor is presented for high-sensitivity in situ measurements of ammonia (hbox {NH}_3) in high-temperature environments, using scanned wavelength modulation spectroscopy (WMS) with first-harmonic-normalized second-harmonic detection (scanned WMS-2 f/1 f) to neutralize the effect of non-absorption losses in the harsh environment. The sensor utilized the sQ(9,9) transition of the fundamental symmetric stretch band of hbox {NH}_3 at 10.39 {\\upmu }hbox {m} and was sinusoidally modulated at 10 kHz and scanned across the peak of the absorption feature at 50 Hz, leading to a detection bandwidth of 100 Hz. A novel technique was used to select an optimal WMS modulation depth parameter that reduced the sensor's sensitivity to spectral interference from hbox {H}_2hbox {O} and hbox {CO}_2 without significantly sacrificing signal-to-noise ratio. The sensor performance was validated by measuring known concentrations of hbox {NH}_3 in a flowing gas cell. The sensor was then demonstrated in a laboratory-scale methane-air burner seeded with hbox {NH}_3, achieving a demonstrated detection limit of 2.8 ± 0.26 ppm hbox {NH}_3 by mole at a path length of 179 cm, equivalence ratio of 0.6, pressure of 1 atm, and temperatures of up to 600 K.

  9. High sensitivity of northeastern broadleaf forest trees to water availability

    NASA Astrophysics Data System (ADS)

    Levesque, M.; Pederson, N.; Andreu-Hayles, L.

    2015-12-01

    Temperate deciduous forests of eastern US provide goods and services to millions of people and play a vital role in the terrestrial carbon and hydrological cycles. However, ongoing climate change and increased in CO2 concentration in the atmosphere (ca) are expected to alter growth and gas exchange of trees, and ultimately forest productivity. Still, the magnitude of these effects is unclear. A better comprehension of the species-specific responses to environmental changes will better inform models and managers on the vulnerability and resiliency of these forests. Tree-ring analysis was combined with δ¹³C and δ18O measurements to investigate growth and physiological responses of red oak (Quercus rubra L.) and tulip poplar (Liriodendron tulipifera L.) in northeastern US to changes in water availability and ca for the period 1950-2014. We found very strong correlations between summer climatic water balance (June-August) and isotopic tree-ring series for δ¹³C (r = -0.65 and -0.73), and δ18O (r = -0.59 and -0.70), for red oak and tulip poplar, respectively. In contrast, tree-ring width was less sensitive to summer water availability (r = 0.33-0.39). Prior to the mid 1980s, low water availability resulted in low stomatal conductance, photosynthesis, and growth. Since that period, pluvial conditions occurring in northeastern US have increased stomatal conductance, carbon uptake, and growth of both species. These findings demonstrate that broadleaf trees in this region could be more sensitive to drought than expected. This appears especially true since much of the calibration period looks wet in a multi-centennial perspective. Further, stronger spatial correlations were found between climate data with tree-ring isotopes than with tree-ring width and the geographical area of the observed δ18O-precipitation response (i.e. the area over which correlations are > 0.5) covers most of the northeastern US. Given the good fit between the isotopic time series and water

  10. Repetitive Immunoassay with a Surface Acoustic Wave Device and a Highly Stable Protein Monolayer for On-Site Monitoring of Airborne Dust Mite Allergens.

    PubMed

    Toma, Koji; Miki, Daisuke; Kishikawa, Chisato; Yoshimura, Naoyuki; Miyajima, Kumiko; Arakawa, Takahiro; Yatsuda, Hiromi; Mitsubayashi, Kohji

    2015-10-20

    This work describes a sensor to be incorporated into the on-site monitoring system of airborne house dust mite (HDM) allergens. A surface acoustic wave (SAW) device was combined with self-assembled monolayers of a highly stable antibody capture protein on the SAW surface that have high resistance to pH change. A sandwich assay was used to measure a HDM allergen, Der f 1 derived from Dermatophagoides farinae. Capture antibodies were cross-linked to a protein G based capture layer (ORLA85) on the sensor surface, thereby only Der f 1 and detection antibodies were regenerated by changing pH, resulting in fast repetition of the measurement. The sensor was characterized through 10 repetitive measurements of Der f 1, which demonstrated high reproducibility of the sensor with the coefficient of variation of 5.6%. The limit of detection (LOD) of the sensor was 6.1 ng·mL(-1), encompassing the standard (20 ng·mL(-1)) set by the World Health Organization. Negligible sensor outputs were observed for five different major allergens including other HDM allergens which tend to have cross-reactivity to Der f 1 and their mixtures with Der f 1. Finally, the sensor lifetime was evaluated by conducting three measurements per day, and the sensor output did not substantially change for 4 days. These characteristics make the SAW immunosensor a promising candidate for incorporation into on-site allergen monitoring systems. PMID:26378678

  11. RF/microwave system high-fidelity modeling and simulation: application to airborne multi-channel receiver system for angle of arrival estimation

    NASA Astrophysics Data System (ADS)

    Wu, Chen; Rajan, Sreeraman; Young, Anne; O'Regan, Christina

    2014-06-01

    In this paper, a high-fidelity RF modeling and simulation framework is demonstrated to model an airborne multi-channel receiver system that is used to estimate the angle of arrival (AoA) of received signals from a stationary emitter. The framework is based on System Tool Kit (STK®), Matlab and SystemVue®. The SystemVue-based multi-channel receiver estimates the AoA of incoming signals using adjacent channel amplitude and phase comparisons, and it estimates the Doppler frequency shift of the aircraft by processing the transmitted and received signals. The estimated AoA and Doppler frequency are compared with the ground-truth data provided by STK to validate the efficacy of the modeling process. Unlike other current RF electronic warfare simulation frameworks, the received signal described herein is formed using the received power, the propagation delay and the transmitted waveform, and does not require information such as Doppler frequency shift or radial velocity of the moving platform from the scenario; hence, the simulation is more computationally efficient. In addition, to further reduce the overall modeling and simulation time, since the high-fidelity model computation is costly, the high-fidelity electronic system model is evoked only when the received power is higher than a predetermined threshold.

  12. Object-based assessment of burn severity in diseased forests using high-spatial and high-spectral resolution MASTER airborne imagery

    NASA Astrophysics Data System (ADS)

    Chen, Gang; Metz, Margaret R.; Rizzo, David M.; Dillon, Whalen W.; Meentemeyer, Ross K.

    2015-04-01

    Forest ecosystems are subject to a variety of disturbances with increasing intensities and frequencies, which may permanently change the trajectories of forest recovery and disrupt the ecosystem services provided by trees. Fire and invasive species, especially exotic disease-causing pathogens and insects, are examples of disturbances that together could pose major threats to forest health. This study examines the impacts of fire and exotic disease (sudden oak death) on forests, with an emphasis on the assessment of post-fire burn severity in a forest where trees have experienced three stages of disease progression pre-fire: early-stage (trees retaining dried foliage and fine twigs), middle-stage (trees losing fine crown fuels), and late-stage (trees falling down). The research was conducted by applying Geographic Object-Based Image Analysis (GEOBIA) to MASTER airborne images that were acquired immediately following the fire for rapid assessment and contained both high-spatial (4 m) and high-spectral (50 bands) resolutions. Although GEOBIA has gradually become a standard tool for analyzing high-spatial resolution imagery, high-spectral resolution data (dozens to hundreds of bands) can dramatically reduce computation efficiency in the process of segmentation and object-based variable extraction, leading to complicated variable selection for succeeding modeling. Hence, we also assessed two widely used band reduction algorithms, PCA (principal component analysis) and MNF (minimum noise fraction), for the delineation of image objects and the subsequent performance of burn severity models using either PCA or MNF derived variables. To increase computation efficiency, only the top 5 PCA and MNF and top 10 PCA and MNF components were evaluated, which accounted for 10% and 20% of the total number of the original 50 spectral bands, respectively. Results show that if no band reduction was applied the models developed for the three stages of disease progression had relatively

  13. Highly heat-sensitive luminophor for recording IR radiation

    SciTech Connect

    Zaitsev, L.M.; Martyshova, N.E.; Pospelova, L.A.; Senashenko, M.V.; Timofeev, Yu.P.

    1988-12-01

    The purpose of this study was to develop and predict the properties of a single-phase crystalline phosphor with an extended range of temperature sensitivity. The luminophors ZnS /times/ CdS mentioned above were used as a matrix to synthesize a luminophor of the new type. Substances exhibiting a different temperature dependence - Ag and Eu - were chosen for activation. The choice of the composition of the base made it possible to rely on the fact that the emission bands of both activators will mutually overlap and that a spectrally uniform crystalline phosphor will be obtained. It was shown that the dynamic range of the power density of the recorded IR radiation can be substantially expanded (up to 30). The receiving luminescent screen is made of a single-phase crystalline phosphor ZnS /times/ CdS with Ag, Eu, and Ni with thermal extinction of both centers of luminescence in different temperature regions, making it possible to obtain a series of screens with well-reproducible characteristics.

  14. Achieving tunable sensitivity in composite high-energy density materials

    NASA Astrophysics Data System (ADS)

    Rashkeev, Sergey; Tsyshevsky, Roman; Kuklja, Maija

    2015-06-01

    Laser irradiation provides a unique opportunity for selective, predictive, and controlled initiation of energetic materials. We propose a consistent micro-scale mechanism of photoexcitation at the interface, formed by a molecular energetic material and a metal oxide. A specific PETN-MgO model composite is used to illustrate and explain seemingly puzzling experiments on selective laser initiation of energetic materials, which reported that the presence of metal oxide additives triggered the photoinitiation by an unusually low energy. We suggest that PETN photodecomposition is catalyzed by oxygen vacancies (F0 centers) at the MgO surface. The proposed model suggests ways to tune sensitivity of energetic molecular materials to photoinitiation. Our quantum-chemical calculations suggest that the structural defects (e.g., oxygen vacancies) strongly interact with the molecular material (e.g., adsorbed energetic molecules) by inducing a charge transfer at the interface and hence play an imperative role in governing both energy absorption and energy release in the system. Our approach and conclusions provide a solid basis for novel design of energetic interfaces with desired properties and offers a new perspective in the field of explosive materials and devices.

  15. Missing Iron-Oxidizing Acidophiles Highly Sensitive to Organic Compounds

    PubMed Central

    Ueoka, Nagayoshi; Kouzuma, Atsushi; Watanabe, Kazuya

    2016-01-01

    The genus Acidithiobacillus includes iron-oxidizing lithoautotrophs that thrive in acidic mine environments. Acidithiobacillus ferrooxidans is a representative species and has been extensively studied for its application to the bioleaching of precious metals. In our attempts to cultivate the type strain of A. ferrooxidans (ATCC 23270T), repeated transfers to fresh inorganic media resulted in the emergence of cultures with improved growth traits. Strains were isolated from the resultant culture by forming colonies on inorganic silica-gel plates. A representative isolate (strain NU-1) was unable to form colonies on agarose plates and was more sensitive to organics, such as glucose, than the type strain of A. ferrooxidans. Strain NU-1 exhibited superior growth traits in inorganic iron media to those of other iron-oxidizing acidithiobacilli, suggesting its potential for industrial applications. A draft genome of NU-1 uncovered unique features in catabolic enzymes, indicating that this strain is not a mutant of the A. ferrooxidans type strain. Our results indicate that the use of inorganic silica-gel plates facilitates the isolation of as-yet-unexamined iron-oxidizing acidithiobacilli from environmental samples and enrichment cultures. PMID:27356527

  16. Toolsets for Airborne Data

    Atmospheric Science Data Center

    2015-04-02

    article title:  Toolsets for Airborne Data     View larger image The ... limit of detection values. Prior to accessing the TAD Web Application ( https://tad.larc.nasa.gov ) for the first time, users must ...

  17. Airborne laser communication technology and flight test

    NASA Astrophysics Data System (ADS)

    Meng, Li-xin; Zhang, Li-zhong; Li, Xiao-ming; Li, Ying-chao; Jiang, Hui-lin

    2015-11-01

    Reconnaissance aircraft is an important node of the space-air-ground integrated information network, on which equipped with a large number of high-resolution surveillance equipment, and need high speed communications equipment to transmit detected information in real time. Currently RF communication methods cannot meet the needs of communication bandwidth. Wireless laser communication has outstanding advantages high speed, high capacity, security, etc., is an important means to solve the high-speed information transmission of airborne platforms. In this paper, detailed analysis of how the system works, the system components, work processes, link power and the key technologies of airborne laser communication were discussed. On this basis, a prototype airborne laser communications was developed, and high-speed, long-distance communications tests were carried out between the two fixed-wing aircraft, and the airborne precision aiming, atmospheric laser communication impacts on laser communication were tested. The experiments ultimately realize that, the communication distance is 144km, the communication rate is 2.5Gbps. The Airborne laser communication experiments provide technical basis for the application of the conversion equipment.

  18. Highly sensitive self-complementary DNA nanoswitches triggered by polyelectrolytes

    NASA Astrophysics Data System (ADS)

    Wu, Jincai; Yu, Feng; Zhang, Zheng; Chen, Yong; Du, Jie; Maruyama, Atsushi

    2015-12-01

    Dimerization of two homologous strands of genomic DNA/RNA is an essential feature of retroviral replication. Herein we show that a cationic comb-type copolymer (CCC), poly(l-lysine)-graft-dextran, accelerates the dimerization of self-complementary stem-loop DNA, frequently found in functional DNA/RNA molecules, such as aptamers. Furthermore, an anionic polymer poly(sodium vinylsulfonate) (PVS) dissociates CCC from the duplex shortly within a few seconds. Then single stem-loop DNA spontaneously transforms from its dimer. Thus we can easily control the dimer and stem-loop DNA by switching on/off CCC activity. Both polyelectrolytes and DNA concentrations are in the nanomole per liter range. The polyelectrolyte-assisted transconformation and sequences design strategy ensures the reversible state control with rapid response and effective switching under physiologically relevant conditions. A further application of this sensitive assembly is to construct an aptamer-type drug delivery system, bind or release functional molecules responding to its transconformation.Dimerization of two homologous strands of genomic DNA/RNA is an essential feature of retroviral replication. Herein we show that a cationic comb-type copolymer (CCC), poly(l-lysine)-graft-dextran, accelerates the dimerization of self-complementary stem-loop DNA, frequently found in functional DNA/RNA molecules, such as aptamers. Furthermore, an anionic polymer poly(sodium vinylsulfonate) (PVS) dissociates CCC from the duplex shortly within a few seconds. Then single stem-loop DNA spontaneously transforms from its dimer. Thus we can easily control the dimer and stem-loop DNA by switching on/off CCC activity. Both polyelectrolytes and DNA concentrations are in the nanomole per liter range. The polyelectrolyte-assisted transconformation and sequences design strategy ensures the reversible state control with rapid response and effective switching under physiologically relevant conditions. A further application of

  19. Laser-induced breakdown spectroscopy with high detection sensitivity

    NASA Astrophysics Data System (ADS)

    Shen, X. K.; Ling, H.; Lu, Y. F.

    2009-02-01

    Laser-induced breakdown spectroscopy (LIBS) with spatial confinement and LIBS combined with laser-induced fluorescence (LIF) have been investigated to improve the detection sensitivity and selectivity of LIBS. An obvious enhancement in the emission intensity of Al atomic lines was observed when a cylindrical wall was placed to spatially confine the plasma plumes. The maximum enhancement factor for the emission intensity of Al atomic lines was measured to be around 10. Assuming local thermodynamic equilibrium conditions, the plasma temperatures are estimated to be in the range from 4000 to 5800 K. It shows that the plasma temperature increased by around 1000 K when the cylindrical confinement was applied. Fast imaging of the laser-induced Al plasmas shows that the plasmas were compressed into a smaller volume with a pipe presented. LIBS-LIF has been investigated to overcome the matrix effects in LIBS for the detection of trace uranium in solids. A wavelength-tunable laser with an optical parametric oscillator was used to resonantly excite the uranium atoms and ions within the plasma plumes generated by a Q-switched Nd:YAG laser. Both atomic and ionic lines can be selected to detect their fluorescence lines. A uranium concentration of 462 ppm in a glass sample can be detected using this technique at an excitation wavelength of 385.96 nm for resonant excitation of U II and a fluorescence line wavelength of 409.01 nm from U II. The mechanism of spatial confinement effects and the influence of relevant operational parameters of LIBS-LIF are discussed.

  20. Highly sensitive vacuum ion pump current measurement system

    DOEpatents

    Hansknecht, John Christopher

    2006-02-21

    A vacuum system comprising: 1) an ion pump; 2) power supply; 3) a high voltage DC--DC converter drawing power from the power supply and powering the vacuum pump; 4) a feedback network comprising an ammeter circuit including an operational amplifier and a series of relay controlled scaling resistors of different resistance for detecting circuit feedback; 5) an optional power block section intermediate the power supply and the high voltage DC--DC converter; and 6) a microprocessor receiving feedback information from the feedback network, controlling which of the scaling resistors should be in the circuit and manipulating data from the feedback network to provide accurate vacuum measurement to an operator.

  1. The airborne laser

    NASA Astrophysics Data System (ADS)

    Lamberson, Steven; Schall, Harold; Shattuck, Paul

    2007-05-01

    The Airborne Laser (ABL) is an airborne, megawatt-class laser system with a state-of-the-art atmospheric compensation system to destroy enemy ballistic missiles at long ranges. This system will provide both deterrence and defense against the use of such weapons during conflicts. This paper provides an overview of the ABL weapon system including: the notional operational concept, the development approach and schedule, the overall aircraft configuration, the technologies being incorporated in the ABL, and the current program status.

  2. A Simple, High-Precision, High-Sensitivity Tracer Assay for N(inf2) Fixation

    PubMed Central

    Montoya, J. P.; Voss, M.; Kahler, P.; Capone, D. G.

    1996-01-01

    We describe a simple, precise, and sensitive experimental protocol for direct measurement of N(inf2) fixation using the conversion of (sup15)N(inf2) to organic N. Our protocol greatly reduces the limit of detection for N(inf2) fixation by taking advantage of the high sensitivity of a modern, multiple-collector isotope ratio mass spectrometer. This instrument allowed measurement of N(inf2) fixation by natural assemblages of plankton in incubations lasting several hours in the presence of relatively low-level (ca. 10 atom%) tracer additions of (sup15)N(inf2) to the ambient pool of N(inf2). The sensitivity and precision of this tracer method are comparable to or better than those associated with the C(inf2)H(inf2) reduction assay. Data obtained in a series of experiments in the Gotland Basin of the Baltic Sea showed excellent agreement between (sup15)N(inf2) tracer and C(inf2)H(inf2) reduction measurements, with the largest discrepancies between the methods occurring at very low fixation rates. The ratio of C(inf2)H(inf2) reduced to N(inf2) fixed was 4.68 (plusmn) 0.11 (mean (plusmn) standard error, n = 39). In these experiments, the rate of C(inf2)H(inf2) reduction was relatively insensitive to assay volume. Our results, the first for planktonic diazotroph populations of the Baltic, confirm the validity of the C(inf2)H(inf2) reduction method as a quantitative measure of N(inf2) fixation in this system. Our (sup15)N(inf2) protocols are comparable to standard C(inf2)H(inf2) reduction procedures, which should promote use of direct (sup15)N(inf2) fixation measurements in other systems. PMID:16535283

  3. Airborne laser scan measurements of winter snow accumulation in high alpine catchments - hydrological implications and verification by ground penetrating radar at glacier surface

    NASA Astrophysics Data System (ADS)

    Helfricht, K.; Keuschnig, M.; Heilig, A.; Mayer, C.; Kuhn, M.

    2012-04-01

    The snow cover as storage of winter precipitation is a substantial source for runoff generation in high mountain catchments. Redistribution of solid precipitation, caused by wind and gravity, leads to a characteristic spatial distribution of snow accumulation which differs from simple model assumption of a homogenous snowpack increasing with altitude. Both, the distinct distribution of snow accumulation and the total amount of SWE stored in the snow cover, affect the magnitude and seasonality of melt water runoff. Complex relations exist between the spatial pattern of snow accumulation and the presence of glaciers and vice versa. For proper hydrological modeling in high mountain catchments, knowledge about snow cover distribution is an important requirement. To date, to evaluate modeling results, spatially insufficient point data on snow depths and SWE are usually available. On catchment scale, optical space-borne remote sensing techniques deliver areal extent of snow cover, but no snow depths and hence no volume of snow cover. Multi-temporal airborne laser scanning (ALS) is an active remote sensing method to obtain elevation changes extensively even in inaccessible alpine terrain. Before the start and at the end of accumulation season of winter 2010/2011, two airborne laser scan acquisitions were performed in the Ötztal Alps (Tirol, Austria). Differences of the respective digital elevation models were interpreted as snow depths and converted into SWE using a simple regression method between snow depths and snow density. Preferred snow accumulation areas were determined, e.g. wind sheltered depressions, the base of steep mountain walls and flat glacier surfaces. At catchment scale, solid precipitation is obviously redistributed from wind exposed mountain ridges to lower elevations, inducing characteristic elevations of maximum snow accumulation. Overall, catchment precipitation derived from snow accumulation is a valuable reference for precipitation approaches in

  4. Variable high pressure processing sensitivities for GII human noroviruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Human norovirus (HuNoV) is the leading cause of foodborne diseases worldwide. High pressure processing (HPP) is one of the most promising non-thermal technologies for decontamination of viral pathogens in foods. However, the survival of HuNoVs by HPP is poorly understood because these viruses cann...

  5. UNCERTAINTY AND SENSITIVITY ANALYSES FOR VERY HIGH ORDER MODELS

    EPA Science Inventory

    While there may in many cases be high potential for exposure of humans and ecosystems to chemicals released from a source, the degree to which this potential is realized is often uncertain. Conceptually, uncertainties are divided among parameters, model, and modeler during simula...

  6. High-sensitivity mass spectrometry with a tandem accelerator

    SciTech Connect

    Henning, W.

    1983-01-01

    The characteristic features of accelerator mass spectrometry are discussed. A short overview is given of the current status of mass spectrometry with high-energy (MeV/nucleon) heavy-ion accelerators. Emphasis is placed on studies with tandem accelerators and on future mass spectrometry of heavier isotopes with the new generation of higher-voltage tandems.

  7. Aptamer-Functionalized Fluorescent Silica Nanoparticles for Highly Sensitive Detection of Leukemia Cells

    NASA Astrophysics Data System (ADS)

    Tan, Juntao; Yang, Nuo; Hu, Zixi; Su, Jing; Zhong, Jianhong; Yang, Yang; Yu, Yating; Zhu, Jianmeng; Xue, Dabin; Huang, Yingying; Lai, Zongqiang; Huang, Yong; Lu, Xiaoling; Zhao, Yongxiang

    2016-06-01

    A simple, highly sensitive method to detect leukemia cells has been developed based on aptamer-modified fluorescent silica nanoparticles (FSNPs). In this strategy, the amine-labeled Sgc8 aptamer was conjugated to carboxyl-modified FSNPs via amide coupling between amino and carboxyl groups. Sensitivity and specificity of Sgc8-FSNPs were assessed using flow cytometry and fluorescence microscopy. These results showed that Sgc8-FSNPs detected leukemia cells with high sensitivity and specificity. Aptamer-modified FSNPs hold promise for sensitive and specific detection of leukemia cells. Changing the aptamer may allow the FSNPs to detect other types of cancer cells.

  8. Aptamer-Functionalized Fluorescent Silica Nanoparticles for Highly Sensitive Detection of Leukemia Cells.

    PubMed

    Tan, Juntao; Yang, Nuo; Hu, Zixi; Su, Jing; Zhong, Jianhong; Yang, Yang; Yu, Yating; Zhu, Jianmeng; Xue, Dabin; Huang, Yingying; Lai, Zongqiang; Huang, Yong; Lu, Xiaoling; Zhao, Yongxiang

    2016-12-01

    A simple, highly sensitive method to detect leukemia cells has been developed based on aptamer-modified fluorescent silica nanoparticles (FSNPs). In this strategy, the amine-labeled Sgc8 aptamer was conjugated to carboxyl-modified FSNPs via amide coupling between amino and carboxyl groups. Sensitivity and specificity of Sgc8-FSNPs were assessed using flow cytometry and fluorescence microscopy. These results showed that Sgc8-FSNPs detected leukemia cells with high sensitivity and specificity. Aptamer-modified FSNPs hold promise for sensitive and specific detection of leukemia cells. Changing the aptamer may allow the FSNPs to detect other types of cancer cells. PMID:27299653

  9. Highly stable and sensitive glucose biosensor based on covalently assembled high density Au nanostructures.

    PubMed

    Si, Peng; Kannan, Palanisamy; Guo, Longhua; Son, Hungsun; Kim, Dong-Hwan

    2011-05-15

    We describe the development of a highly stable and sensitive glucose biosensor based on the nanohybrid materials derived from gold nanoparticles (AuNPs) and multi-walled carbon nanotubes (MWCNT). The biosensing platform was developed by using layer-by-layer (LBL) self-assembly of the nanohybrid materials and the enzyme glucose oxidase (GOx). A high density of AuNPs and MWCNT nanocomposite materials were constructed by alternate self assembly of thiol functionalized MWCNTs and AuNPs, followed by chemisoption of GOx. The surface morphology of multilayered AuNPs/MWCNT structure was characterized by field emission-scanning electron microscope (FE-SEM), and the surface coverage of AuNPs was investigated by cyclic voltammetry (CV), showing that 5 layers of assembly achieves the maximum particle density on electrode. The immobilization of GOx was monitored by electrochemical impedance spectroscopy (EIS). CV and amperometry methods were used to study the electrochemical oxidation of glucose at physiological pH 7.4. The Au electrode modified with five layers of AuNPs/MWCNT composites and GOx exhibited an excellent electrocatalytic activity towards oxidation of glucose, which presents a wide liner range from 20 μM to 10 mM, with a sensitivity of 19.27 μA mM(-1) cm(-2). The detection limit of present modified electrode was found to be 2.3 μM (S/N=3). In addition, the resulting biosensor showed a faster amperometric current response (within 3 s) and low apparent Michaelis-Menten constant (K(m)(app)). Our present study shows that the high density of AuNPs decorated MWCNT is a promising nanohybrid material for the construction of enzyme based electrochemical biosensors. PMID:21454070

  10. Advances in High Energy Solid-State 2-micron Laser Transmitter Development for Ground and Airborne Wind and CO2 Measurements

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta; Chen, Songsheng; Kavaya, Michael J.; Trieu, Bo; Bai, Yingxin; Petzar, Paul; Modlin, Edward A.; Koch, Grady; Beyon, Jeffrey

    2010-01-01

    Sustained research efforts at NASA Langley Research Center (LaRC) during last fifteen years have resulted in a significant advancement in 2-micron diode-pumped, solid-state laser transmitter for wind and carbon dioxide measurement from ground, air and space-borne platform. Solid-state 2-micron laser is a key subsystem for a coherent Doppler lidar that measures the horizontal and vertical wind velocities with high precision and resolution. The same laser, after a few modifications, can also be used in a Differential Absorption Lidar (DIAL) system for measuring atmospheric CO2 concentration profiles. Researchers at NASA Langley Research Center have developed a compact, flight capable, high energy, injection seeded, 2-micron laser transmitter for ground and airborne wind and carbon dioxide measurements. It is capable of producing 250 mJ at 10 Hz by an oscillator and one amplifier. This compact laser transmitter was integrated into a mobile trailer based coherent Doppler wind and CO2 DIAL system and was deployed during field measurement campaigns. This paper will give an overview of 2-micron solid-state laser technology development and discuss results from recent ground-based field measurements.

  11. PCF Based Sensor with High Sensitivity, High Birefringence and Low Confinement Losses for Liquid Analyte Sensing Applications

    PubMed Central

    Ademgil, Huseyin; Haxha, Shyqyri

    2015-01-01

    In this paper, we report a design of high sensitivity Photonic Crystal Fiber (PCF) sensor with high birefringence and low confinement losses for liquid analyte sensing applications. The proposed PCF structures are designed with supplementary elliptical air holes in the core region vertically-shaped V-PCF and horizontally-shaped H-PCF. The full vectorial Finite Element Method (FEM) simulations performed to examine the sensitivity, the confinement losses, the effective refractive index and the modal birefringence features of the proposed elliptical air hole PCF structures. We show that the proposed PCF structures exhibit high relative sensitivity, high birefringence and low confinement losses simultaneously for various analytes. PMID:26694408

  12. The highly sensitive brain: an fMRI study of sensory processing sensitivity and response to others' emotions

    PubMed Central

    Acevedo, Bianca P; Aron, Elaine N; Aron, Arthur; Sangster, Matthew-Donald; Collins, Nancy; Brown, Lucy L

    2014-01-01

    Background Theory and research suggest that sensory processing sensitivity (SPS), found in roughly 20% of humans and over 100 other species, is a trait associated with greater sensitivity and responsiveness to the environment and to social stimuli. Self-report studies have shown that high-SPS individuals are strongly affected by others' moods, but no previous study has examined neural systems engaged in response to others' emotions. Methods This study examined the neural correlates of SPS (measured by the standard short-form Highly Sensitive Person [HSP] scale) among 18 participants (10 females) while viewing photos of their romantic partners and of strangers displaying positive, negative, or neutral facial expressions. One year apart, 13 of the 18 participants were scanned twice. Results Across all conditions, HSP scores were associated with increased brain activation of regions involved in attention and action planning (in the cingulate and premotor area [PMA]). For happy and sad photo conditions, SPS was associated with activation of brain regions involved in awareness, integration of sensory information, empathy, and action planning (e.g., cingulate, insula, inferior frontal gyrus [IFG], middle temporal gyrus [MTG], and PMA). Conclusions As predicted, for partner images and for happy facial photos, HSP scores were associated with stronger activation of brain regions involved in awareness, empathy, and self-other processing. These results provide evidence that awareness and responsiveness are fundamental features of SPS, and show how the brain may mediate these traits. PMID:25161824

  13. Airborne lidar global positioning investigations

    NASA Technical Reports Server (NTRS)

    Krabill, W. B.

    1988-01-01

    The Global Positioning System (GPS) network of satellites shows high promise of revolutionizing methods for conducting surveying, navigation, and positioning. This is especially true in the case of airborne or satellite positioning. A single GPS receiver (suitably adapted for aircraft deployment) can yield positioning accuracies (world-wide) in the order of 30 to 50 m vertically, as well as horizontally. This accuracy is dramatically improved when a second GPS receiver is positioned at a known horizontal and vertical reference. Absolute horizontal and vertical positioning of 1 to 2 m are easily achieved over areas of separation of tens of km. If four common satellites remain in lock in both receivers, then differential phase pseudo-ranges on the GPS L-band carrier can be utilized to achieve accuracies of + or - 10 cm and perhaps as good as + or - 2 cm. The initial proof of concept investigation for airborne positioning using the phase difference between the airborne and stationary GPS receivers was conducted and is examined.

  14. Differential Sensitivity Theory applied to the MESA code for high pressure interactions

    NASA Astrophysics Data System (ADS)

    Maudlin, P. J.; Henninger, R. J.; Harstad, E. N.

    A technique called Differential Sensitivity Theory (DST) is applied to the system of equations solved by the MESA hydrocode. DST uses adjoint techniques to determine exact sensitivity derivatives, i.e., if R is a calculational result of interest (response R) and alpha(sub i) is a calculational input (parameter alpha(sub i)), then (partial derivative)R/(partial derivative)alpha(sub i) is defined as the sensitivity. The advantage of using DST is that for an n-parameter problem all n sensitivities can be obtained by integrating the solutions from only two calculations, a MESA calculation and its corresponding adjoint calculation using an Adjoint Continuum Mechanics code (ACM). This work describes the derivation and solution of the appropriate set of adjoint and sensitivity equations for the purpose of computing sensitivities for high-rate two-dimensional, multi-component, high deformation problems. As an example, results are presented for a flyer plate problem.

  15. Differential Sensitivity Theory applied to the MESA code for high pressure interactions

    SciTech Connect

    Maudlin, P.J.; Henninger, R.J.; Harstad, E.N.

    1993-07-01

    A technique called Differential Sensitivity Theory (DST) is applied to the system of equations solved by the MESA hydrocode. DST uses adjoint techniques to determine exact sensitivity derivatives, i.e., if R is a calculational result of interest (response R) and {alpha}{sub i} is a calculational input (parameter {alpha}{sub i}), then {partial_derivative}R/{partial_derivative}{alpha}{sub i} is defined as the sensitivity. The advantage of using DST is that for an n-parameter problem all n sensitivities can be obtained by integrating the solutions from only two calculations, a MESA calculation and its corresponding adjoint calculation using an Adjoint Continuum Mechanics code (ACM). This work describes the derivation and solution of the appropriate set of adjoint and sensitivity equations for the purpose of computing sensitivities for high-rate two-dimensional, multi-component, high deformation problems. As an example, results are presented for a flyer plate problem.

  16. High-speed asynchronous optical sampling for high-sensitivity detection of coherent phonons

    NASA Astrophysics Data System (ADS)

    Dekorsy, T.; Taubert, R.; Hudert, F.; Schrenk, G.; Bartels, A.; Cerna, R.; Kotaidis, V.; Plech, A.; Köhler, K.; Schmitz, J.; Wagner, J.

    2007-12-01

    A new optical pump-probe technique is implemented for the investigation of coherent acoustic phonon dynamics in the GHz to THz frequency range which is based on two asynchronously linked femtosecond lasers. Asynchronous optical sampling (ASOPS) provides the performance of on all-optical oscilloscope and allows us to record optically induced lattice dynamics over nanosecond times with femtosecond resolution at scan rates of 10 kHz without any moving part in the set-up. Within 1 minute of data acquisition time signal-to-noise ratios better than 107 are achieved. We present examples of the high-sensitivity detection of coherent phonons in superlattices and of the coherent acoustic vibration of metallic nanoparticles.

  17. Dynamics and sensitivity analysis of high-frequency conduction block

    NASA Astrophysics Data System (ADS)

    Ackermann, D. Michael; Bhadra, Niloy; Gerges, Meana; Thomas, Peter J.

    2011-10-01

    The local delivery of extracellular high-frequency stimulation (HFS) has been shown to be a fast acting and quickly reversible method of blocking neural conduction and is currently being pursued for several clinical indications. However, the mechanism for this type of nerve block remains unclear. In this study, we investigate two hypotheses: (1) depolarizing currents promote conduction block via inactivation of sodium channels and (2) the gating dynamics of the fast sodium channel are the primary determinate of minimal blocking frequency. Hypothesis 1 was investigated using a combined modeling and experimental study to investigate the effect of depolarizing and hyperpolarizing currents on high-frequency block. The results of the modeling study show that both depolarizing and hyperpolarizing currents play an important role in conduction block and that the conductance to each of three ionic currents increases relative to resting values during HFS. However, depolarizing currents were found to promote the blocking effect, and hyperpolarizing currents were found to diminish the blocking effect. Inward sodium currents were larger than the sum of the outward currents, resulting in a net depolarization of the nodal membrane. Our experimental results support these findings and closely match results from the equivalent modeling scenario: intra-peritoneal administration of the persistent sodium channel blocker ranolazine resulted in an increase in the amplitude of HFS required to produce conduction block in rats, confirming that depolarizing currents promote the conduction block phenomenon. Hypothesis 2 was investigated using a spectral analysis of the channel gating variables in a single-fiber axon model. The results of this study suggested a relationship between the dynamical properties of specific ion channel gating elements and the contributions of corresponding conductances to block onset. Specifically, we show that the dynamics of the fast sodium inactivation gate are

  18. Highly sensitive passive radio frequency identification based sensor systems

    NASA Astrophysics Data System (ADS)

    Wissenwasser, J.; Vellekoop, M.; Heer, R.

    2010-02-01

    A novel platform for sensor applications based on radio frequency (rf) identification technology, where passive tags are powered by the rf-field of a reader, is presented. The sophisticated energy harvesting system of the tag enables a blanking of the rf-field for a defined period, while supplying the tag electronics with a highly stable voltage and a power of 25 mW for 100 ms. During this time, span measurements can be performed without interferences of the rf-field. The presented tags work without batteries and are designed for impedance measurements on microbiological cell cultures under physiological relevant conditions as well as in harsh environments.

  19. Highly sensitive passive radio frequency identification based sensor systems.

    PubMed

    Wissenwasser, J; Vellekoop, M; Heer, R

    2010-02-01

    A novel platform for sensor applications based on radio frequency (rf) identification technology, where passive tags are powered by the rf-field of a reader, is presented. The sophisticated energy harvesting system of the tag enables a blanking of the rf-field for a defined period, while supplying the tag electronics with a highly stable voltage and a power of 25 mW for 100 ms. During this time, span measurements can be performed without interferences of the rf-field. The presented tags work without batteries and are designed for impedance measurements on microbiological cell cultures under physiological relevant conditions as well as in harsh environments. PMID:20192517

  20. Purification of ethanol for highly sensitive self-assembly experiments

    PubMed Central

    Barbe, Kathrin; Kind, Martin; Pfeiffer, Christian

    2014-01-01

    Summary Ethanol is the preferred solvent for the formation of self-assembled monolayers (SAMs) of thiolates on gold. By applying a thin film sensor system, we could demonstrate that even the best commercial qualities of ethanol contain surface-active contaminants, which can compete with the desired thiolates for surface sites. Here we present that gold nanoparticles deposited onto zeolite X can be used to remove these contaminants by chemisorption. This nanoparticle-impregnated zeolite does not only show high capacities for surface-active contaminants, such as thiols, but can be fully regenerated via a simple pyrolysis protocol. PMID:25161861

  1. Dynamics and sensitivity analysis of high frequency conduction block

    PubMed Central

    Ackermann, D. Michael; Bhadra, Niloy; Gerges, Meana; Thomas, Peter J.

    2012-01-01

    The local delivery of extracellular high frequency stimulation (HFS) has been shown to be a fast acting and quickly reversible method of blocking neural conduction, and is currently being pursued for several clinical indications. However, the mechanism for this type of nerve block remains unclear. In this study, we investigate two hypotheses: 1) That depolarizing currents promote conduction block via inactivation of sodium channels, and 2) that the gating dynamics of the fast sodium channel are the primary determinate of minimal blocking frequency. Hypothesis 1 was investigated using a combined modeling and experimental study to investigate the effect of depolarizing and hyperpolarizing currents on high frequency block. The results of the modeling study show that both depolarizing and hyperpolarizing currents play an important role in conduction block and that the conductance to each of three ionic currents increases relative to resting values during HFS. However, depolarizing currents were found to promote the blocking effect, and hyperpolarizing currents were found to diminish the blocking effect. Inward sodium currents were larger than the sum of the outward currents, resulting in a net depolarization of the nodal membrane. Our experimental results support these findings and closely match results from the equivalent modeling scenario: intra-peritoneal administration of the persistent sodium channel blocker ranolazine resulted in an increase in the amplitude of HFS required to produce conduction block in rats, confirming that depolarizing currents promote the conduction block phenomenon. Hypothesis 2 was investigated using a spectral analysis of the channel gating variables in a single fiber axon model. The results of this study suggested a relationship between the dynamical properties of specific ion channel gating elements and the contributions of corresponding conductances to block onset. Specifically, we show that the dynamics of the fast sodium inactivation

  2. Porous tungsten oxide nanoflakes for highly alcohol sensitive performance

    NASA Astrophysics Data System (ADS)

    Xiao, J.; Liu, P.; Liang, Y.; Li, H. B.; Yang, G. W.

    2012-10-01

    Porous tungsten oxide (WO3) nanoflakes have been synthesized by a simple and green approach in an ambient environment. As a precursor solution a polycrystalline hydrated tungstite (H2WO4.H2O) nanoparticles colloid was first prepared by pulsed-laser ablation of a tungsten target in water. The H2WO4.H2O nanoflakes were produced by 72 h aging treatment at room temperature. Finally, porous WO3 nanoflakes were synthesized by annealing at 800 °C for 4 h. Considering the large surface-to-volume ratio of porous nanoflakes, a porous WO3 nanoflake gas sensor was fabricated, which exhibits an excellent sensor response performance to alcohol concentrations in the range of 20 to 600 ppm under low working temperature. This high response was attributed to the highly crystalline and porous flake-like morphology, which leads to effective adsorption and desorption, and provides more active sites for the gas molecules' reaction. These findings showed that the porous tungsten oxide nanoflake has great potential in gas-sensing performance.

  3. AIRBORNE CONTAMINANTS IN WESTERN NORTH AMERICAN NATIONAL PARKS--WHAT WE KNOW AND WANT TO LEARN

    EPA Science Inventory

    The National Park Service initiated the Western Airborne Contaminants Assessment Project (WACAP) in 2002 to determine if airborne contaminants from regional or distant sources have an impact on remote (typically high elevation) western ecosystems, including Alaska. Eight Nationa...

  4. Birth Weight, Current Anthropometric Markers, and High Sensitivity C-Reactive Protein in Brazilian School Children

    PubMed Central

    Pellanda, Lucia Campos

    2015-01-01

    Studies have shown associations of birth weight with increased concentrations of high sensitivity C-reactive protein. This study assessed the relationship between birth weight, anthropometric and metabolic parameters during childhood, and high sensitivity C-reactive protein. A total of 612 Brazilian school children aged 5–13 years were included in the study. High sensitivity C-reactive protein was measured by particle-enhanced immunonephelometry. Nutritional status was assessed by body mass index, waist circumference, and skinfolds. Total cholesterol and fractions, triglycerides, and glucose were measured by enzymatic methods. Insulin sensitivity was determined by the homeostasis model assessment method. Statistical analysis included chi-square test, General Linear Model, and General Linear Model for Gamma Distribution. Body mass index, waist circumference, and skinfolds were directly associated with birth weight (P < 0.001, P = 0.001, and P = 0.015, resp.). Large for gestational age children showed higher high sensitivity C-reactive protein levels (P < 0.001) than small for gestational age. High birth weight is associated with higher levels of high sensitivity C-reactive protein, body mass index, waist circumference, and skinfolds. Large for gestational age altered high sensitivity C-reactive protein and promoted additional risk factor for atherosclerosis in these school children, independent of current nutritional status. PMID:25874126

  5. A novel high resolution, high sensitivity SPECT detector for molecular imaging of cardiovascular diseases

    NASA Astrophysics Data System (ADS)

    Cusanno, F.; Argentieri, A.; Baiocchi, M.; Colilli, S.; Cisbani, E.; De Vincentis, G.; Fratoni, R.; Garibaldi, F.; Giuliani, F.; Gricia, M.; Lucentini, M.; Magliozzi, M. L.; Majewski, S.; Marano, G.; Musico, P.; Musumeci, M.; Santavenere, F.; Torrioli, S.; Tsui, B. M. W.; Vitelli, L.; Wang, Y.

    2010-05-01

    Cardiovascular diseases are the most common cause of death in western countries. Understanding the rupture of vulnerable atherosclerotic plaques and monitoring the effect of innovative therapies of heart failure is of fundamental importance. A flexible, high resolution, high sensitivity detector system for molecular imaging with radionuclides on small animal models has been designed for this aim. A prototype has been built using tungsten pinhole and LaBr3(Ce) scintillator coupled to Hamamatsu Flat Panel PMTs. Compact individual-channel readout has been designed, built and tested. Measurements with phantoms as well as pilot studies on mice have been performed, the results show that the myocardial perfusion in mice can be determined with sufficient precision. The detector will be improved replacing the Hamamatsu Flat Panel with Silicon Photomultipliers (SiPMs) to allow integration of the system with MRI scanners. Application of LaBr3(Ce) scintillator coupled to photosensor with high photon detection efficiency and excellent energy resolution will allow dual-label imaging to monitor simultaneously the cardiac perfusion and the molecular targets under investigation during the heart therapy.

  6. Method for rapid, high sensitivity tritiated water extraction

    SciTech Connect

    Failor, R.; Belovodsky, L.; Gaevoy, V.; Golubev, A.

    1997-04-20

    We have developed a thermal vacuum desorption process to rapidly extract water from environmental samples for tritium analysis. Thermal vacuum desorption allows for extraction of the moisture from the sample within a few hours in a form and quantity suitable for liquid scintillation counting and allows detection of tritium at the levels of <2 Bq/L of milk, <0.5 Bq/gm of vegetation, and < 0.5 Bq/gin of soil. We developed a prototype unit that can process batches of twenty or more samples within 24 hours. Early data shows that a high percentage of water is extracted reproducibly without enrichment or depletion of the tritium content. The quench coefficient of the extracted water is low allowing for accurate, direct liquid scintillation counting. Excellent comparison has been observed with results using freeze-dry lypholization as the water extraction method.

  7. Stretchable and highly sensitive graphene-on-polymer strain sensors

    PubMed Central

    Li, Xiao; Zhang, Rujing; Yu, Wenjian; Wang, Kunlin; Wei, Jinquan; Wu, Dehai; Cao, Anyuan; Li, Zhihong; Cheng, Yao; Zheng, Quanshui; Ruoff, Rodney S.; Zhu, Hongwei

    2012-01-01

    The use of nanomaterials for strain sensors has attracted attention due to their unique electromechanical properties. However, nanomaterials have yet to overcome many technological obstacles and thus are not yet the preferred material for strain sensors. In this work, we investigated graphene woven fabrics (GWFs) for strain sensing. Different than graphene films, GWFs undergo significant changes in their polycrystalline structures along with high-density crack formation and propagation mechanically deformed. The electrical resistance of GWFs increases exponentially with tensile strain with gauge factors of ~103 under 2~6% strains and ~106 under higher strains that are the highest thus far reported, due to its woven mesh configuration and fracture behavior, making it an ideal structure for sensing tensile deformation by changes in strain. The main mechanism is investigated, resulting in a theoretical model that predicts very well the observed behavior. PMID:23162694

  8. Airborne GLM Simulator (FEGS)

    NASA Astrophysics Data System (ADS)

    Quick, M.; Blakeslee, R. J.; Christian, H. J., Jr.; Stewart, M. F.; Podgorny, S.; Corredor, D.

    2015-12-01

    Real time lightning observations have proven to be useful for advanced warning and now-casting of severe weather events. In anticipation of the launch of the Geostationary Lightning Mapper (GLM) onboard GOES-R that will provide continuous real time observations of total (both cloud and ground) lightning, the Fly's Eye GLM Simulator (FEGS) is in production. FEGS is an airborne instrument designed to provide cal/val measurements for GLM from high altitude aircraft. It consists of a 5 x 5 array of telescopes each with a narrow passband filter to isolate the 777.4 nm neutral oxygen emission triplet radiated by lightning. The telescopes will measure the optical radiance emitted by lightning that is transmitted through the cloud top with a temporal resolution of 10 μs. When integrated on the NASA ER-2 aircraft, the FEGS array with its 90° field-of-view will observe a cloud top area nearly equal to a single GLM pixel. This design will allow FEGS to determine the temporal and spatial variation of light that contributes to a GLM event detection. In addition to the primary telescope array, the instrument includes 5 supplementary optical channels that observe alternate spectral emission features and will enable the use of FEGS for interesting lightning physics applications. Here we present an up-to-date summary of the project and a description of its scientific applications.

  9. (abstract) A Miniature, High-Sensitivity, Electron-Tunneling Accelerometer

    NASA Technical Reports Server (NTRS)

    Gabrielson, Thomas B.; Rockstad, Howard K.; Tang, Tony K.

    1994-01-01

    A prototype low-noise accelerometer has been fabricated with an electron-tunneling transducer. By measuring the tunneling current between an electrode on the proof mass and a feedback-controlled monitor electrode, very small accelerations can be detected with high responsivity. This particular prototype (10x10x1.5 mm) was designed for underwater acoustic measurement from a few hertz to 1 kHz. The measured responsivity below the fundamental device resonance at 100 Hz is roughly 1500 volts per m/s(sup 2) with a measured noise spectral density of 10(sup -6) m/s(sup 2) per root hertz or less between 30 and 300 Hz. The noise floor is controlled primarily by 1/f noise in the tunneling current although the noise floor reaches the theoretical molecular-agitation limit at 100 hertz. The responsivity and directivity of the device were measured in a standard gradient-hydrophone calibrator; the noise floor was determined in a vacuum-ionization chamber assembled from commercial off-the-shelf components; and the detailed dynamics of the proof-mass motion were examined using a heterodyne laser interferometer that was scanned across the surface and synchronously detected with respect to the excitation.

  10. Enhanced Laboratory Sensitivity to Variation of the Fine-Structure Constant using Highly Charged Ions

    SciTech Connect

    Berengut, J. C.; Dzuba, V. A.; Flambaum, V. V.

    2010-09-17

    We study atomic systems that are in the frequency range of optical atomic clocks and have enhanced sensitivity to potential time variation of the fine-structure constant {alpha}. The high sensitivity is due to coherent contributions from three factors: high nuclear charge Z, high ionization degree, and significant differences in the configuration composition of the states involved. Configuration crossing keeps the frequencies in the optical range despite the large ionization energies. We discuss a few promising examples that have the largest {alpha} sensitivities seen in atomic systems.

  11. Draft Genome Sequence of Streptomyces fradiae ATCC 19609, a Strain Highly Sensitive to Antibiotics.

    PubMed

    Bekker, Olga B; Klimina, Ksenia M; Vatlin, Aleksey A; Zakharevich, Natalia V; Kasianov, Artem S; Danilenko, Valery N

    2014-01-01

    We report here a sequence of the genome of the Streptomyces fradiae ATCC 19609 strain, initially isolated from the soil, which produces tylosin. S. fradiae is highly sensitive to different classes of antibiotics, compared to the sensitivities of other bacteria. We have identified 9 groups of genes directly or indirectly involved in the resistome formation. PMID:25477406

  12. Reward Sensitivity and Substance Abuse in Middle School and High School Students

    ERIC Educational Resources Information Center

    Genovese, Jeremy E. C.; Wallace, Deborah

    2007-01-01

    In this study, the authors investigated the relation between reward and punishment sensitivity and adolescent substance use. The sample (N = 216; 130 girls, 85 boys) was drawn from high school and middle school students enrolled in a Midwestern suburban school district. Participants completed a substance use questionnaire and the Sensitivity to…

  13. Hypoxia-sensitive reporter system for high-throughput screening.

    PubMed

    Tsujita, Tadayuki; Kawaguchi, Shin-ichi; Dan, Takashi; Baird, Liam; Miyata, Toshio; Yamamoto, Masayuki

    2015-01-01

    The induction of anti-hypoxic stress enzymes and proteins has the potential to be a potent therapeutic strategy to prevent the progression of ischemic heart, kidney or brain diseases. To realize this idea, small chemical compounds, which mimic hypoxic conditions by activating the PHD-HIF-α system, have been developed. However, to date, none of these compounds were identified by monitoring the transcriptional activation of hypoxia-inducible factors (HIFs). Thus, to facilitate the discovery of potent inducers of HIF-α, we have developed an effective high-throughput screening (HTS) system to directly monitor the output of HIF-α transcription. We generated a HIF-α-dependent reporter system that responds to hypoxic stimuli in a concentration- and time-dependent manner. This system was developed through multiple optimization steps, resulting in the generation of a construct that consists of the secretion-type luciferase gene (Metridia luciferase, MLuc) under the transcriptional regulation of an enhancer containing 7 copies of 40-bp hypoxia responsive element (HRE) upstream of a mini-TATA promoter. This construct was stably integrated into the human neuroblastoma cell line, SK-N-BE(2)c, to generate a reporter system, named SKN:HRE-MLuc. To improve this system and to increase its suitability for the HTS platform, we incorporated the next generation luciferase, Nano luciferase (NLuc), whose longer half-life provides us with flexibility for the use of this reporter. We thus generated a stably transformed clone with NLuc, named SKN:HRE-NLuc, and found that it showed significantly improved reporter activity compared to SKN:HRE-MLuc. In this study, we have successfully developed the SKN:HRE-NLuc screening system as an efficient platform for future HTS. PMID:25746387

  14. Confidence Level and Sensitivity Limits in High Contrast Imaging

    SciTech Connect

    Marois, C

    2007-11-07

    In long adaptive optics corrected exposures, exoplanet detections are currently limited by speckle noise originating from the telescope and instrument optics, and it is expected that such noise will also limit future high-contrast imaging instruments for both ground and space-based telescopes. Previous theoretical analysis have shown that the time intensity variations of a single speckle follows a modified Rician. It is first demonstrated here that for a circular pupil this temporal intensity distribution also represents the speckle spatial intensity distribution at a fix separation from the point spread function center; this fact is demonstrated using numerical simulations for coronagraphic and non-coronagraphic data. The real statistical distribution of the noise needs to be taken into account explicitly when selecting a detection threshold appropriate for some desired confidence level. In this paper, a technique is described to obtain the pixel intensity distribution of an image and its corresponding confidence level as a function of the detection threshold. Using numerical simulations, it is shown that in the presence of speckles noise, a detection threshold up to three times higher is required to obtain a confidence level equivalent to that at 5{sigma} for Gaussian noise. The technique is then tested using TRIDENT CFHT and angular differential imaging NIRI Gemini adaptive optics data. It is found that the angular differential imaging technique produces quasi-Gaussian residuals, a remarkable result compared to classical adaptive optic imaging. A power-law is finally derived to predict the 1-3 x 10{sup -7} confidence level detection threshold when averaging a partially correlated non-Gaussian noise.

  15. Confidence Level and Sensitivity Limits in High Contrast Imaging

    SciTech Connect

    Marois, C; LaFreniere, D; Macintosh, B; Doyon, R

    2008-06-02

    In long adaptive optics corrected exposures, exoplanet detections are currently limited by speckle noise originating from the telescope and instrument optics, and it is expected that such noise will also limit future high-contrast imaging instruments for both ground and space-based telescopes. Previous theoretical analysis have shown that the time intensity variations of a single speckle follows a modified Rician. It is first demonstrated here that for a circular pupil this temporal intensity distribution also represents the speckle spatial intensity distribution at a fix separation from the point spread function center; this fact is demonstrated using numerical simulations for coronagraphic and non-coronagraphic data. The real statistical distribution of the noise needs to be taken into account explicitly when selecting a detection threshold appropriate for some desired confidence level. In this paper, a technique is described to obtain the pixel intensity distribution of an image and its corresponding confidence level as a function of the detection threshold. Using numerical simulations, it is shown that in the presence of speckles noise, a detection threshold up to three times higher is required to obtain a confidence level equivalent to that at 5{sigma} for Gaussian noise. The technique is then tested using TRIDENT CFHT and angular differential imaging NIRI Gemini adaptive optics data. It is found that the angular differential imaging technique produces quasi-Gaussian residuals, a remarkable result compared to classical adaptive optic imaging. A power-law is finally derived to predict the 1-3 x 10{sup -7} confidence level detection threshold when averaging a partially correlated non-Gaussian noise.

  16. Confidence Level and Sensitivity Limits in High-Contrast Imaging

    NASA Astrophysics Data System (ADS)

    Marois, Christian; Lafrenière, David; Macintosh, Bruce; Doyon, René

    2008-01-01

    In long adaptive optics corrected exposures, exoplanet detections are currently limited by speckle noise originating from the telescope and instrument optics, and it is expected that such noise will also limit future high-contrast imaging instruments for both ground- and space-based telescopes. Previous theoretical analyses have shown that the time intensity variations of a single speckle follow a modified Rician. It is first demonstrated here that for a circular pupil, this temporal intensity distribution also represents the speckle spatial intensity distribution at a fixed separation from the point-spread function center; this fact is demonstrated using numerical simulations for coronagraphic and noncoronagraphic data. The real statistical distribution of the noise needs to be taken into account explicitly when selecting a detection threshold appropriate for some desired confidence level (CL). In this paper, a technique is described to obtain the pixel intensity distribution of an image and its corresponding CL as a function of the detection threshold. Using numerical simulations, it is shown that in the presence of speckle noise, a detection threshold up to 3 times higher is required to obtain a CL equivalent to that at 5 σ for Gaussian noise. The technique is then tested on data acquired by simultaneous spectral differential imaging with TRIDENT and by angular differential imaging with NIRI. It is found that the angular differential imaging technique produces quasi-Gaussian residuals, a remarkable result compared to classical adaptive optic imaging. Finally, a power law is derived to predict the 1 - 3 × 10-7 CL detection threshold when averaging a partially correlated non-Gaussian noise. Based on observations obtained at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of

  17. Active airborne contamination control using electrophoresis

    SciTech Connect

    Veatch, B.D.

    1994-06-01

    In spite of our best efforts, radioactive airborne contamination continues to be a formidable problem at many of the Department of Energy (DOE) weapons complex sites. For workers that must enter areas with high levels of airborne contamination, personnel protective equipment (PPE) can become highly restrictive, greatly diminishing productivity. Rather than require even more restrictive PPE for personnel in some situations, the Rocky Flats Plant (RFP) is actively researching and developing methods to aggressively combat airborne contamination hazards using electrophoretic technology. With appropriate equipment, airborne particulates can be effectively removed and collected for disposal in one simple process. The equipment needed to implement electrophoresis is relatively inexpensive, highly reliable, and very compact. Once airborne contamination levels are reduced, less PPE is required and a significant cost savings may be realized through decreased waste and maximized productivity. Preliminary ``cold,`` or non-radioactive, testing results at the RFP have shown the technology to be effective on a reasonable scale, with several potential benefits and an abundance of applications.

  18. Airborne space laser communication system and experiments

    NASA Astrophysics Data System (ADS)

    Li, Xiao-Ming; Zhang, Li-zhong; Meng, Li-Xin

    2015-11-01

    Airborne space laser communication is characterized by its high speed, anti-electromagnetic interference, security, easy to assign. It has broad application in the areas of integrated space-ground communication networking, military communication, anti-electromagnetic communication. This paper introduce the component and APT system of the airborne laser communication system design by Changchun university of science and technology base on characteristic of airborne laser communication and Y12 plan, especially introduce the high communication speed and long distance communication experiment of the system that among two Y12 plans. In the experiment got the aim that the max communication distance 144Km, error 10-6 2.5Gbps - 10-7 1.5Gbps capture probability 97%, average capture time 20s. The experiment proving the adaptability of the APT and the high speed long distance communication.

  19. High-resolution and high-sensitivity tephra-inferred fingerprints in stalagmite geochemistry

    NASA Astrophysics Data System (ADS)

    Wu, Chung-Che; Burger, Marcel; Günther, Detlef; Hattendorf, Bodo; Shen, Chuan-Chou

    2016-04-01

    High-resolution and high-sensitivity rare earth elements (REEs) profiles of Holocene stalagmites collected from East Timor (8° 47' S, 126° 23' E) provide detailed fluctuation information which can be inferred to super volcano eruptions. Since REEs are enriched in igneous rocks (~ μg/g) but depleted in carbonates (~ ng/g to pg/g), REEs preserved in stalagmites are acted as an ideal proxy of tephra-inferred signature; however, due to the low REE abundances in most natural stalagmite samples (1-100s ng/g), overall applicability has been sharply limited. Here we develop and apply an improved LA-GED-ICPMS methodology to determine REEs in such low concentration stalagmites. Two pronounced REE peaks occur where their concentrations sharply increased by 1-2 order of magnitudes, from 10s of ng/g to 100s of ng/g. This event was dated at 80 thousand years ago by U-Th methods. Nevertheless, the accurate timing of this REE anomalous event should be examined carefully. Also more multi-proxies evidences such as stable isotopes δ13C, δ18O, and S isotope, should be provided in the future.

  20. Development of a 300,000-pixel ultrahigh-speed high-sensitivity CCD

    NASA Astrophysics Data System (ADS)

    Ohtake, H.; Hayashida, T.; Kitamura, K.; Arai, T.; Yonai, J.; Tanioka, K.; Maruyama, H.; Etoh, T. Goji; Poggemann, D.; Ruckelshausen, A.; van Kuijk, H.; Bosiers, Jan T.

    2006-02-01

    We are developing an ultrahigh-speed, high-sensitivity broadcast camera that is capable of capturing clear, smooth slow-motion videos even where lighting is limited, such as at professional baseball games played at night. In earlier work, we developed an ultrahigh-speed broadcast color camera1) using three 80,000-pixel ultrahigh-speed, highsensitivity CCDs2). This camera had about ten times the sensitivity of standard high-speed cameras, and enabled an entirely new style of presentation for sports broadcasts and science programs. Most notably, increasing the pixel count is crucially important for applying ultrahigh-speed, high-sensitivity CCDs to HDTV broadcasting. This paper provides a summary of our experimental development aimed at improving the resolution of CCD even further: a new ultrahigh-speed high-sensitivity CCD that increases the pixel count four-fold to 300,000 pixels.