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Sample records for airborne high sensitivity

  1. 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.

  2. 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. .

  3. beta-(1,3)-Glucan exposure assessment by passive airborne dust sampling and new sensitive immunoassays.

    PubMed

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

    2010-02-01

    Associations between house dust-associated beta-(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 beta-(1,3)-glucan exposure assessment. The objective of this study was to develop inexpensive but highly sensitive enzyme immunoassays to measure airborne beta-(1,3)-glucans in low-exposure environments, like homes. Specificities of available anti-beta-(1,3)-glucan antibodies were defined by direct and inhibition experiments. Three suitable antibody combinations were selected for sandwich EIAs. beta-(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 beta-(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 beta-(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 beta-(1,3)-glucan levels correlated moderately with beta-(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 beta-(1,3)-glucan sandwich EIA with EDC sampling now allows assessment in large-scale population studies of exposure to airborne beta-(1,3)-glucans in homes or other low-exposure environments.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.…

  12. 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.

  13. 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.

  14. HySpex ODIN-1024: a new high-resolution airborne HSI system

    NASA Astrophysics Data System (ADS)

    Blaaberg, Søren; Løke, Trond; Baarstad, Ivar; Fridman, Andrei; Koirala, Pesal

    2014-06-01

    HySpex ODIN-1024 is a next generation state-of the-art airborne hyperspectral imaging system developed by Norsk Elektro Optikk AS. Near perfect coregistration between VNIR and SWIR is achieved by employing a novel common fore-optics design and a thermally stabilized housing. Its unique design and the use of state-of-the-art MCT and sCMOS sensors provide the combination of high sensitivity and low noise, low spatial and spectral misregistration (smile and keystone) and a very high resolution (1024 pixels in the merged data products). In addition to its supreme data quality, HySpex ODIN-1024 includes real-time data processing functionalities such as real-time georeferencing of acquired images. It also features a built-in onboard calibration system to monitor the stability of the instrument. The paper presents data and results from laboratory tests and characterizations, as well as results from airborne measurements.

  15. 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).

  16. 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.

  17. Efficient and sensitive identification and quantification of airborne pollen using next-generation DNA sequencing.

    PubMed

    Kraaijeveld, Ken; de Weger, Letty A; Ventayol García, Marina; Buermans, Henk; Frank, Jeroen; Hiemstra, Pieter S; den Dunnen, Johan T

    2015-01-01

    Pollen monitoring is an important and widely used tool in allergy research and creation of awareness in pollen-allergic patients. Current pollen monitoring methods are microscope-based, labour intensive and cannot identify pollen to the genus level in some relevant allergenic plant groups. Therefore, a more efficient, cost-effective and sensitive method is needed. Here, we present a method for identification and quantification of airborne pollen using DNA sequencing. Pollen is collected from ambient air using standard techniques. DNA is extracted from the collected pollen, and a fragment of the chloroplast gene trnL is amplified using PCR. The PCR product is subsequently sequenced on a next-generation sequencing platform (Ion Torrent). Amplicon molecules are sequenced individually, allowing identification of different sequences from a mixed sample. We show that this method provides an accurate qualitative and quantitative view of the species composition of samples of airborne pollen grains. We also show that it correctly identifies the individual grass genera present in a mixed sample of grass pollen, which cannot be achieved using microscopic pollen identification. We conclude that our method is more efficient and sensitive than current pollen monitoring techniques and therefore has the potential to increase the throughput of pollen monitoring.

  18. 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.

  19. Aerosol classification by airborne high spectral resolution lidar observations

    NASA Astrophysics Data System (ADS)

    Groß, S.; Esselborn, M.; Weinzierl, B.; Wirth, M.; Fix, A.; Petzold, A.

    2013-03-01

    During four aircraft field experiments with the DLR research aircraft Falcon in 1998 (LACE), 2006 (SAMUM-1) and 2008 (SAMUM-2 and EUCAARI), airborne High Spectral Resolution Lidar (HSRL) and in situ measurements of aerosol microphysical and optical properties were performed. Altogether, the properties of six different aerosol types and aerosol mixtures - Saharan mineral dust, Saharan dust mixtures, Canadian biomass burning aerosol, African biomass burning mixture, anthropogenic pollution aerosol, and marine aerosol have been studied. On the basis of this extensive HSRL data set, we present an aerosol classification scheme which is also capable to identify mixtures of different aerosol types. We calculated mixing lines that allowed us to determine the contributing aerosol types. The aerosol classification scheme was supported by backward trajectory analysis and validated with in-situ measurements. Our results demonstrate that the developed aerosol mask is capable to identify complex stratifications with different aerosol types throughout the atmosphere.

  20. Aerosol classification by airborne high spectral resolution lidar observations

    NASA Astrophysics Data System (ADS)

    Groß, S.; Esselborn, M.; Weinzierl, B.; Wirth, M.; Fix, A.; Petzold, A.

    2012-10-01

    During four aircraft field experiments with the DLR research aircraft Falcon in 1998 (LACE), 2006 (SAMUM-1) and 2008 (SAMUM-2 and EUCAARI), airborne High Spectral Resolution Lidar (HSRL) and in situ measurements of aerosol microphysical and optical properties were performed. Altogether, the properties of six different aerosol types and aerosol mixtures - Saharan mineral dust, Saharan dust mixtures, Canadian biomass burning aerosol, African biomass burning aerosol, anthropogenic pollution aerosol, and marine aerosol have been studied. On the basis of this extensive HSRL data set, we present an aerosol classification scheme which is also capable to identify mixtures of different aerosol types. We calculated mixing lines that allowed us to determine the contributing aerosol types. The aerosol classification scheme was validated with in-situ measurements and backward trajectory analyses. Our results demonstrate that the developed aerosol mask is capable to identify complex stratifications with different aerosol types throughout the atmosphere.

  1. Real-time detection of airborne viruses on a mass-sensitive device

    NASA Astrophysics Data System (ADS)

    Lee, Joonhyung; Jang, Jaesung; Akin, Demir; Savran, Cagri A.; Bashir, Rashid

    2008-07-01

    We present real-time detection of airborne Vaccinia viruses using quartz crystal microbalance (QCM) in an integrated manner. Vaccinia viruses were aerosolized and neutralized using an electrospray aerosol generator, transported into the QCM chamber, and captured by a QCM crystal. The capture of the viruses on the QCM crystal resulted in frequency shifts proportional to the number of viruses. The capture rate varied linearly with the concentration of initial virus suspensions (8.5×108-8.5×1010particles/ml) at flow rates of 2.0 and 1.1l/min. This work demonstrates the general potential of mass sensitive detection of nanoscale biological entities in air.

  2. 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.

  3. Sensitivity of the eyes to airborne irritant stimuli: influence of individual characteristics.

    PubMed

    Kjaergaard, S; Pedersen, O F; Mølhave, L

    1992-01-01

    The purpose of this study was to measure trigeminal sensitivity of the eyes to irritative exposures and to examine the influence of individual characteristics, e.g., gender, age, and smoking, on this sensitivity. During an experimental study, 158 of 2,025 randomly selected volunteers were examined for sensory irritation threshold in the eyes to carbon dioxide (CO2). Eyes were exposed to progressive concentrations of CO2 (10, 20, 40, 80, and 160 ml/l), until the subject claimed a distinct irritation. Each exposure level lasted 2 min. A special exposure mask system was used for eyes-only exposure. No significant dependence of gender or smoking was found, but subjects who were less than 40 y of age were more sensitive than were the elderly subjects. Subjects who reported frequent "sick building syndrome" irritation symptoms had lower thresholds (i.e., higher sensitivity). The CO2 threshold was related to skin irritation sensitivity, i.e., response to lactic acid smeared on the cheek, and there were indications that occupational stress was associated with low thresholds. Studies of irritation to n-decane indicate that the CO2 threshold may be an important factor in the prediction of individual sensitivity to irritation from airborne pollutants. The CO2 threshold of the eyes may be of value in the evaluation of hypersensitivity to indoor air pollution. Furthermore, the threshold may be used to assess important relationships between the different trigeminal innervated areas, e.g., skin and eyes. Finally, the method has the advantage of avoiding interference from olfactory stimulation. PMID:1540002

  4. 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.

  5. 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

  6. Simultaneous determination of airborne carbamates in workplace by high performance liquid chromatography with fluorescence detection.

    PubMed

    Li, Hong-Ping; Li, Jen-Hou; Li, Gwo-Chen; Jen, Jen-Fon

    2004-06-17

    A high performance liquid chromatography with fluorescence (HPLC-F) detector was examined to simultaneous determination of airborne carbamates in the workplace of manufactory. The OVS-2 air sampling tube filled with glass fiber filter or quartz fiber and combined filter/XAD-2 were evaluated to collect nine commonly used carbamates (Carbofuran, Isoprocarb, Methomyl, Metolcarb, Thiodicarb, Carbaryl, Oxamyl, Methiocarb, and Prpoxur) from the air of manufactory in high humidity country. After being extracted with acetonitrile from sampling tubes, the carbamates were determined by high performance liquid chromatography with fluorescence detection posterior to on-line derivatization. The collection of carbamates and the recovery of extraction from glass wool fiber in several concentration levels, and from quartz filter were evaluated. The storage stability of carbamates was also tested. Results indicated that the HPLC-fluorescence method offers satisfactory resolution and sensitivity in carbamate analysis. With the glass fiber filter and combined filter/XAD-2, the Carbofuran, Isoprocarb, Methomyl, Metolcarb, and Thiodicarb were stable for a 28-day storage test, Carbaryl and Oxamyl for 14 days, and Methiocarb and Prpoxur for 7 days. All of these pesticides were with detection limit of 3mugm(-3). It is suited for environmental monitoring. The airborne carbamates in different areas of the manufactory were measured.

  7. 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.

  8. 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

  9. 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.

  10. 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.…

  11. 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.

  12. 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.

  13. Design of the processing chain for a high-altitude, airborne, single-photon lidar mapping instrument

    NASA Astrophysics Data System (ADS)

    Gluckman, Joshua

    2016-05-01

    Processing data from high-altitude, airborne lidar instruments that employ single-photon sensitive, arrayed detectors poses several challenges. Arrayed detectors produce large volumes of data; single-photon sensitive detectors produce high levels of noise; and high-altitude operation makes accurate geolocation difficult to achieve. To address these challenges, a unique and highly automated processing chain for high-altitude, single-photon, airborne lidar mapping instruments has been developed. The processing chain includes algorithms for coincidence processing, noise reduction, self-calibration, data registration, and geolocation accuracy enhancement. Common to all single-photon sensitive systems is a high level of background photon noise. A key step in the processing chain is a fast and accurate algorithm for density estimation, which is used to separate the lidar signal from the background photon noise, permitting the use of a wide-range gate and daytime operation. Additional filtering algorithms are used to remove or reduce other sources of system and detector noise. An optimization algorithm that leverages the conical scan pattern of the instrument is used to improve geolocation and to self-calibrate the system.

  14. Fiber-coupled high resolution infrared array spectrometer for the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Glenar, D. A.; Reuter, D.; Mumma, M. J.; Chin, G.; Wiedemann, G.; Jennings, D.

    1990-01-01

    A novel cryogenic grating spectrometer (FCAS) is being designed for observations of volatiles in cometary and planetary atmospheres, and in newly forming planetary systems. The instrument features two-dimensional detector arrays coupled to a high-dispersion echelle by infrared fibers, and will achieve a spectral resolving power of about 40,000. The primary observational platform for this instrument will be the Kuiper Airborne Observatory, but it will also be configured for use at ground-based observatories. Initially, the spectrometer will use a 58 x 62, 1- to 5-micron InSb array. Larger-format IR arrays and arrays of different composition, will later be incorporated as they become available. The instrument will be used in two modes. The first uses a large format IR array in the spectral image plane for the customary one-dimensional spectral-one-dimensional spatial coverage. In the second mode, a massive, coherent bundle of infrared transmitting ZrF4 fibers will be installed after the dispersive element, to reformat the two-dimensional array into an elongated one-dimensional array for wide spectral coverage, allowing multiple lines to be measured in a single integration with high sensitivity. The overall instrument design is discussed, and the system sensitivity is estimated.

  15. 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.

  16. 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.

  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. CASIMIR: a high resolution far-IR/submm spectrometer for airborne astronomy

    NASA Astrophysics Data System (ADS)

    Edgar, Michael L.; Emprechtinger, Martin; Karpov, Alexandre; Lin, Robert; Lin, Sean; Maiwald, Frank; Mehdi, Imran; Miller, David; Radford, Simon J. E.; Rice, Frank; Ward, John; Zmuidzinas, Jonas

    2010-07-01

    CASIMIR, the Caltech Airborne Submillimeter Interstellar Medium Investigations Receiver, is a far-infrared and submillimeter heterodyne spectrometer, being developed for the Stratospheric Observatory For Infrared Astronomy, SOFIA. CASIMIR will use newly developed superconducting-insulating-superconducting (SIS) mixers. Combined with the 2.5 m mirror of SOFIA, these detectors will allow observations with high sensitivity to be made in the frequency range from 500 GHz up to 1.4 THz. Initially, at least 5 frequency bands in this range are planned, each with a 4-8 GHz IF passband. Up to 4 frequency bands will be available on each flight and bands may be swapped readily between flights. The local oscillators for all bands are synthesized and tuner-less, using solid state multipliers. CASIMIR also uses a novel, commercial, field-programmable gate array (FPGA) based, fast Fourier transform spectrometer, with extremely high resolution, 22000 (268 kHz at 6 GHz), yielding a system resolution > 106. CASIMIR is extremely well suited to observe the warm, ~ 100K, interstellar medium, particularly hydrides and water lines, in both galactic and extragalactic sources. We present an overview of the instrument, its capabilities and systems. We also describe recent progress in development of the local oscillators and present our first astronomical observations obtained with the new type of spectrometer.

  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. 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...

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

    NASA Astrophysics Data System (ADS)

    Paul, George; Gowda, Prasanna H.; Vara Prasad, P. V.; Howell, Terry A.; Staggenborg, Scott A.; Neale, Christopher M. U.

    2013-09-01

    In this study, Surface Energy Balance Algorithm for Land (SEBAL) was evaluated for its ability to derive aerodynamic components and surface energy fluxes from very high resolution airborne remote sensing data acquired during the Bushland Evapotranspiration and Agricultural Remote Sensing Experiment 2008 (BEAREX08) in Texas, USA. Issues related to hot and cold pixel selection and the underlying assumptions of difference between air and surface temperature (dT) being linearly related to the surface temperature were also addressed. Estimated instantaneous evapotranspiration (ET) and other components of the surface energy balance were compared with measured data from four large precision weighing lysimeter fields, two each managed under irrigation and dryland conditions. Instantaneous ET was estimated with overall mean bias error and root mean square error (RMSE) of 0.13 and 0.15 mm h-1 (23.8 and 28.2%) respectively, where relatively large RMSE was contributed by dryland field. Sensitivity analysis of the hot and cold pixel selection indicated that up to 20% of the variability in ET estimates could be attributed to differences in the surface energy balance and roughness properties of the anchor pixels. Adoption of an excess resistance to heat transfer parameter model into SEBAL significantly improved the instantaneous ET estimates.

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. Millimeter-Wave Airborne Interferometry for High-accuracy Topography Mapping

    NASA Astrophysics Data System (ADS)

    Moller, D.; Hensley, S.; Wu, X.; Rodriguez, E.

    2011-12-01

    In April 2009, an airborne Ka-band single pass interferometric SAR (GLISTIN-A) was demonstrated as a modification to the UAVSAR system. GLISTIN-A was developed under the NASA International Polar Year program to demonstrate swath-mapping for ice-surface topography. Instrument performance confirmed swath widths over the ice between 5-7km, with height precisions ranging from 30cm-3m at a 3m x 3m posting. However processing challenges were encountered on several fronts to achieve the required accuracies including, aircraft motion sensitivity, multipath and systematic drifts. A combination of processor optimization, a modified phase-screen and motion-compensation implementations were able to minimize the impact of these systematic error sources. Funded by the NASA Earth Science Technology Office, upgrades are currently underway to improve the performance (swath >10km) and portability of GLISTIN-A. The upgraded GLISTIN-A will be compatible with the GlobalHawk making Antarctica regional mapping feasible. Beyond this, the surface water and ocean topography (SWOT) mission slated for launch in 2019, needs an airborne sensor to support pre-mission phenomenology measurements and mission calibration and valibration (cal/val). SWOT is unique and distinct from precursor ocean altimetry missions in some notable regards: 1) 100km+ of swath will provide complete ocean elevation coverage, 2) in addition the land surface water will be mapped for storage measurement and discharge estimation and 3) Ka-band single-pass interferometry will produce the 2-D water surface elevation (WSE) maps. In support of SWOT, en-route to Greenland, GLISTIN-A collected a limited amount of data over surface-water targets in North Dakota. While instructive as a preliminary validation of Ka-band interferometry over inland water bodies, further application is limited because GLISTIN-A itself was not designed to address SWOT needs. While ideal for a the ice topography mapping application, the combination of

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. Automated counting of airborne asbestos fibers by a high-throughput microscopy (HTM) method.

    PubMed

    Cho, Myoung-Ock; Yoon, Seonghee; Han, Hwataik; Kim, Jung Kyung

    2011-01-01

    Inhalation of airborne asbestos causes serious health problems such as lung cancer and malignant mesothelioma. The phase-contrast microscopy (PCM) method has been widely used for estimating airborne asbestos concentrations because it does not require complicated processes or high-priced equipment. However, the PCM method is time-consuming and laborious as it is manually performed off-site by an expert. We have developed a high-throughput microscopy (HTM) method that can detect fibers distinguishable from other spherical particles in a sample slide by image processing both automatically and quantitatively. A set of parameters for processing and analysis of asbestos fiber images was adjusted for standard asbestos samples with known concentrations. We analyzed sample slides containing airborne asbestos fibers collected at 11 different workplaces following PCM and HTM methods, and found a reasonably good agreement in the asbestos concentration. Image acquisition synchronized with the movement of the robotic sample stages followed by an automated batch processing of a stack of sample images enabled us to count asbestos fibers with greatly reduced time and labors. HTM should be a potential alternative to conventional PCM, moving a step closer to realization of on-site monitoring of asbestos fibers in air.

  16. 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.

  17. 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.

  18. Initial Field Measurements with the Multisensor Airborne Radiation Survey (MARS) High Purity Germanium (HPGe) Detector Array

    SciTech Connect

    Fast, James E.; Bonebrake, Christopher A.; Dorow, Kevin E.; Glasgow, Brian D.; Jensen, Jeffrey L.; Morris, Scott J.; Orrell, John L.; Pitts, W. Karl; Rohrer, John S.; Todd, Lindsay C.

    2010-06-29

    Abstract: The Multi-sensor Airborne Radiation Survey (MARS) project has developed a new single cryostat detector array design for high purity germanium (HPGe) gamma ray spectrometers that achieves the high detection efficiency required for stand-off detection and actionable characterization of radiological threats. This approach is necessary since a high efficiency HPGe detector can only be built as an array due to limitations in growing large germanium crystals. The system is ruggedized and shock mounted for use in a variety of field applications. This paper reports on results from initial field measurements conducted in a truck and on two different boats.

  19. 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.

  20. Differences in salt sensitivity of four deciduous tree species to soil or airborne salt.

    PubMed

    Paludan-Müller, Georg; Saxe, Henrik; Pedersen, Lars Bo; Randrup, Thomas Barfoed

    2002-02-01

    Seedlings of four deciduous tree species maple (Acer pseudoplatanus), beech (Fagus sylvatica), horse chestnut (Aesculus hippocastanum) and lime (Tilia cordata) were exposed to de-icing salt (NaCl) either through the soil or applied to the above ground plant parts. A soil solution of 1.65 g l-1 NaCl was maintained from the start of the experiment in January 1999 until termination in June 1999. The main effects caused by salt treatment through the soil were a reduction in photosynthesis of up to 50% and the development of leaf chlorosis or necrosis covering up to 50% of the total leaf area for the most sensitive species (lime and beech); maple and horse chestnut were relatively tolerant. There was no significant correlation between Cl or Na concentration in leaves and the relative sensitivity of the species. Saturated salt solution was applied to bark, buds or leaf scars on two occasions three weeks apart during the winter season. This affected the timing of bud break with delays of up to eight days compared with the controls. In the most sensitive species the above ground salt treatments partly prevented bud break (beech) or reduced photosynthesis (lime). Uptake through the bark was most important for the development of stress effects, compared with uptake through the other above ground plant parts.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. High sensitivity knitted fabric strain sensors

    NASA Astrophysics Data System (ADS)

    Xie, Juan; Long, Hairu; Miao, Menghe

    2016-10-01

    Wearable sensors are increasingly used in smart garments for detecting and transferring vital signals and body posture, movement and respiration. Existing fabric strain sensors made from metallized yarns have low sensitivity, poor comfort and low durability to washing. Here we report a knitted fabric strain sensor made from a cotton/stainless steel (SS) fibre blended yarn which shows much higher sensitivity than sensors knitted from metallized yarns. The fabric feels softer than pure cotton textiles owing to the ultrafine stainless steel fibres and does not lose its electrical property after washing. The reason for the high sensitivity of the cotton/SS knitted fabric sensor was explored by comparing its sensing mechanism with the knitted fabric sensor made from metallized yarns. The results show that the cotton/SS yarn-to-yarn contact resistance is highly sensitive to strain applied to hooked yarn loops.

  6. 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

  7. 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.

  8. 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

  9. 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.

  10. High sensitivity optically pumped quantum magnetometer.

    PubMed

    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/Hz(½) over a bandwidth of 26 Hz and that this sensitivity drops to 130 pT/Hz(½) 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

  11. 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

  12. High sensitivity optically pumped quantum magnetometer.

    PubMed

    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/Hz(½) over a bandwidth of 26 Hz and that this sensitivity drops to 130 pT/Hz(½) 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.

  13. Successful kidney transplantation in highly sensitized patients.

    PubMed

    Zhang, Weijie; Chen, Dong; Chen, Zhishui; Zeng, Fanjun; Ming, Changsheng; Lin, Zhengbin; Zhou, Ping; Chen, Gang; Chen, Xiaoping

    2011-03-01

    Highly sensitized patients experience an increased number of rejection episodes and have poorer graft survival rates; hence, sensitization is a significant barrier to both access to and the success of organ transplantation. This study reports our experience in kidney transplantation in highly sensitized patients. Fourteen patients with sensitization or high levels of panelreactive antibodies (PRA) were studied. All patients were desensitized with pre-transplant intravenous immunoglobulin (IVIG)/plasmapheresis (PP) with or without rituximab and thymoglobulin induction therapy, combined with a Prograf/MMF/Pred immunosuppressive regimen. Of 14 patients, 10 showed good graft functions without acute rejection (AR) episodes. Acute cellular rejection in two patients was reversed by methylprednisolone. Two patients underwent antibody-mediated rejection; one was treated with PP/IVIG successfully, whereas the other lost graft functions due to the de novo production of donor-specific antibodies (DSA). Graft functions were stable, and there were no AR episodes in other patients. Conclusively, desensitization using PP/IVIG with or without rituximab increases the likelihood of successful live-donor kidney transplantation in sensitized recipients. PMID:21681679

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Improved method for estimating tree crown diameter using high-resolution airborne data

    NASA Astrophysics Data System (ADS)

    Brovkina, Olga; Latypov, Iscander Sh.; Cienciala, Emil; Fabianek, Tomas

    2016-04-01

    Automatic mapping of tree crown size (radius, diameter, or width) from remote sensing can provide a major benefit for practical and scientific purposes, but requires the development of accurate methods. This study presents an improved method for average tree crown diameter estimation at a forest plot level from high-resolution airborne data. The improved method consists of the combination of a window binarization procedure and a granulometric algorithm, and avoids the complicated crown delineation procedure that is currently used to estimate crown size. The systematic error in average crown diameter estimates is corrected with the improved method. The improved method is tested with coniferous, beech, and mixed-species forest plots based on airborne images of various spatial resolutions. The absolute (quantitative) accuracy of the improved crown diameter estimates is comparable or higher for both monospecies plots and mixed-species plots than the current methods. The ability of the improved method to produce good estimates for average crown diameters for monoculture and mixed species, to use remote sensing data of various spatial resolution and to operate in automatic mode promisingly suggests its applicability to a wide range of forest systems.

  19. 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.

  20. Environmental Sensitivity among Wisconsin High School Students.

    ERIC Educational Resources Information Center

    Sivek, Daniel J.

    2002-01-01

    A two-phase study was conducted to assess influences on environmental sensitivity (ES) in Wisconsin high school students. Three categories of influences emerged from phase I: environmental, role model, and personality. The influence most frequently cited by students as most important was time spent outdoors. Develops a profile of environmentally…

  1. Single photon detector with high polarization sensitivity

    PubMed Central

    Guo, Qi; Li, Hao; You, LiXing; Zhang, WeiJun; Zhang, Lu; Wang, Zhen; Xie, XiaoMing; Qi, Ming

    2015-01-01

    Polarization is one of the key parameters of light. Most optical detectors are intensity detectors that are insensitive to the polarization of light. A superconducting nanowire single photon detector (SNSPD) is naturally sensitive to polarization due to its nanowire structure. Previous studies focused on producing a polarization-insensitive SNSPD. In this study, by adjusting the width and pitch of the nanowire, we systematically investigate the preparation of an SNSPD with high polarization sensitivity. Subsequently, an SNSPD with a system detection efficiency of 12% and a polarization extinction ratio of 22 was successfully prepared. PMID:25875225

  2. 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.

  3. High levels of airborne ultrafine and fine particulate matter in indoor ice arenas.

    PubMed

    Rundell, Kenneth W

    2003-03-01

    The high prevalence of airway dysfunction among ice arena athletes may be related to rink air exposure; in particular, high concentrations of ultrafine and fine particulate matter (0.02-1.0 micro m diameter, PM(1)) from ice resurfacing machines may enhance airway inflammation and hyperreactivity. The purpose of this study was to identify levels of PM(1) emitted from ice resurfacing machines used in indoor ice arenas, and to compare [PM(1)] pre- and post-resurfacing to each other and to outdoor [PM(1)]. Multiple one Hz measurements were recorded on 28 different days as 15-s mean of PM(1).cm(-3) for 2 min at 1-1.5 m "above ice" in 10 rinks pre- and post-resurfacing, with measured airborne PM(1) outside each rink to be used individual rink references. Rink PM(1).cm(-3) was approximately 30 times greater than PM(1).cm(-3) outside the respective rinks (p <.05). Rink values were 104.2 +/- 59.3 x 10(3) PM(1).cm(-3) during prime usage, compared to outdoor values of 3.8 +/- 2.5 x 10(3) PM(1).cm(-3). Ice resurfacing increased PM(1).cm(-3) 4-fold (p <.05). No difference in PM(1) emissions between gasoline and propane powered resurfacing machines was identified. The rate of PM(1) dissipation after resurfacing was highly variable between rinks and probably dependent upon rink ventilation and resurfacing machine engine efficiency. Gas-powered edging increased PM(1).cm(-3) 18-fold and 158-fold versus pre-edging rink and outdoor values, respectively. We conclude that the primary source of airborne indoor rink PM(1) is internal combustion ice-resurfacing machines and that this poor air quality may be causal to the unique and high prevalence of airway dysfunction in ice arena athletes.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. [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.

  12. 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.

  13. 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

  14. [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

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. Sunglint effects on the characterization of optically active substances in high spatial resolution airborne hyperspectral images

    NASA Astrophysics Data System (ADS)

    Streher, A. S.; Faria Barbosa, C. Clemente; Soares Galvão, L.; Goodman, J. A.; Silva, T. S.

    2013-05-01

    Sunglint, also known as the specular reflection of light from water surfaces, is a component of sensor-received radiance that represents a confounding factor on the characterization of water bodies by remote sensing. In airborne remote sensing images, the effect of sunglint can be minimized by optimizing the flight paths, directing the sensor towards or away from the Sun, and by keeping solar zenith angles between 30° and 60°. However, these guidelines cannot always be applied, often due to the irregular spatial pattern of lakes, estuaries and coastlines. The present study assessed the impact of sunglint on the relationship between the optically active substances (OAS) concentration, in optically complex waters, and the spectral information provided by an airborne high spatial resolution hyperspectral sensor (SpecTIR). The Ibitinga reservoir, located in southeastern Brazil (state of São Paulo), was selected as the study area because of its meandering shape. As a result, there is demanding constant changes in data acquisition geometry to achieve complete coverage, therefore not allowing sunglint conditions to be minimized during image acquisition. Field data collection was carried out on October 23 and 24, 2011. During these two days, 15 water stations along the reservoir were sampled, concurrently with the SpecTIR image acquisition in 357 bands (398-2455 nm) and at 3 m spatial resolution. Chlorophyll, pheophytin, total suspended solids, organic and inorganic suspended solids and colored dissolved matter were determined in laboratory. The images were corrected for the atmospheric effects using the Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes (FLAASH) algorithm and then geometrically corrected. In order to evaluate the sunglint effects on the OAS characterization, the images were corrected for such effects using the deglint algorithm from Goodman et al. (2008). The SpecTIR 662-nm band reflectance was selected to be correlated to the OAS due to

  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. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  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. Highly sensitive immunosensor using a nanofluidic preconcentrator.

    PubMed

    Liao, Ke-Pan; Sung, Kung-Bin

    2008-01-01

    This paper presents a micro-/nanofluidic biochip for enhanced sensitivity of immunoassay. By using a protein preconcentrator based on nanofluidic filters, we greatly improve the binding kinetics of immunoassay. A shallow nanofluidic channel connecting two microchannels for ion-selective filter is etched on the glass surface and sealed by PDMS/Glass irreversible bonding treated with O2 plasma. Our device achieved a 10(5) fold increase in protein concentration with 12 minutes of preconcentration. For applying the preconcentrator to immunoassay, we fabricated a novel device with a thin layer of Au sputtered near the nanochannel to provide a substrate for antibody immobilization and a sensing area at the site of highly concentrated proteins. After increasing the concentration of antibody and target antigen by multiple sample preconcentration steps, the binding kinetics of immunoassay can be significantly improved.

  9. A high sensitive roll angle interferometer

    NASA Astrophysics Data System (ADS)

    Le, Yanfen; Hou, Wenmei; Hu, Kai; Ju, Aisong

    2013-01-01

    A roll angle interferometer with high sensitivity is designed in this paper. Two sets of centrosymmetric beams are used to travel through the measurement and reference arms of the roll angle interferometer which contains two specific optical devices: wedge prism assembly and wedge mirror assembly. The optical path change in both arms caused by roll is converted into phase shift which can be measured by interferometer. Because of the adoption of the centrosymmetric measurement structure, the straightness errors, yaw error and pitch error can be avoided and the dead path is minimized, so that the stability and the accuracy of the measurement can be greatly enhanced. The resolution for the roll measurement is about 0.006″ with the measurement range of ±1°.

  10. 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.

  11. Separating mixtures of aerosol types in airborne High Spectral Resolution Lidar data

    NASA Astrophysics Data System (ADS)

    Burton, S. P.; Vaughan, M. A.; Ferrare, R. A.; Hostetler, C. A.

    2013-09-01

    Knowledge of aerosol type is important for source attribution and for determining the magnitude and assessing the consequences of aerosol radiative forcing. 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. This paper extends the work of earlier researchers by using the aerosol intensive parameters measured by the NASA Langley Research Center airborne High Spectral Resolution Lidar (HSRL-1) to develop a comprehensive and unified set of rules for characterizing the external mixing of several key aerosol intensive parameters: extinction-to-backscatter ratio (i.e. lidar ratio), backscatter color ratio, and depolarization ratio. We present the mixing rules in a particularly simple form that leads easily to mixing rules for the covariance matrices that describe aerosol distributions, rather than just scalar values of measured parameters. These rules can be applied to infer mixing ratios from the lidar-observed aerosol parameters, even for cases without significant depolarization. We demonstrate our technique with measurement curtains from three HSRL-1 flights which exhibit mixing between two aerosol types, urban pollution plus dust, marine plus dust, and smoke plus marine. For these cases, we infer a time-height cross-section of mixing ratio along the flight track, and partition aerosol extinction into portions attributed to the two pure types.

  12. Separating mixtures of aerosol types in airborne High Spectral Resolution Lidar data

    NASA Astrophysics Data System (ADS)

    Burton, S. P.; Vaughan, M. A.; Ferrare, R. A.; Hostetler, C. A.

    2014-02-01

    Knowledge of aerosol type is important for determining the magnitude and assessing the consequences of aerosol radiative forcing, and can provide useful information for source attribution studies. 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. This paper extends the work of earlier researchers by using the aerosol intensive parameters measured by the NASA Langley Research Center airborne High Spectral Resolution Lidar (HSRL-1) to develop a comprehensive and unified set of rules for characterizing the external mixing of several key aerosol intensive parameters: extinction-to-backscatter ratio (i.e., lidar ratio), backscatter color ratio, and depolarization ratio. We present the mixing rules in a particularly simple form that leads easily to mixing rules for the covariance matrices that describe aerosol distributions, rather than just single values of measured parameters. These rules can be applied to infer mixing ratios from the lidar-observed aerosol parameters, even for cases without significant depolarization. We demonstrate our technique with measurement curtains from three HSRL-1 flights which exhibit mixing between two aerosol types, urban pollution plus dust, marine plus dust, and smoke plus marine. For these cases, we infer a time-height cross-section of extinction mixing ratio along the flight track, and partition aerosol extinction into portions attributed to the two pure types.

  13. Detection of harvested trees in forests from repeated high density airborne laser scanning

    NASA Astrophysics Data System (ADS)

    Pietrzyk, P. J.; Lindenbergh, R. C.

    2014-05-01

    Identification of harvested and fallen trees is a prerequisite for the detection and measurement of changes in forests. This paper presents a three step approach to monitor harvested and fallen trees based on direct comparison of repeated high density airborne LIDAR data. In a first step differences between data sets are obtained from a point to point comparison, such that the data can be reduced to the deviating points only. Secondly, the resulting points are clustered into spatially connected regions using region growing. Finally, individual trees are extracted from the clusters by analysing their relative proximity and by analysing geometric properties of points in the clusters. Two data sets, acquired at a four year interval and covering a forest with mainly deciduous trees, are compared. First results show that most points relating to a change can be extracted and that clustering of these with region growing enables us to efficiently separate harvested and fallen trees from the remaining trees. Grouped harvested trees could not be separated using the region growing approach due to touching crowns. Segmentation of these using spectral clustering however identified individual regions well, but the results depend mainly on the pre-defined number of clusters. Crowns of grouped trees can be therefore separated if the number of trees is known.

  14. 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.

  15. 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

  16. 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%).

  17. Transportable high sensitivity small sample radiometric calorimeter

    SciTech Connect

    Wetzel, J.R.; Biddle, R.S.; Cordova, B.S.; Sampson, T.E.; Dye, H.R.; McDow, J.G.

    1998-12-31

    A new small-sample, high-sensitivity transportable radiometric calorimeter, which can be operated in different modes, contains an electrical calibration method, and can be used to develop secondary standards, will be described in this presentation. The data taken from preliminary tests will be presented to indicate the precision and accuracy of the instrument. The calorimeter and temperature-controlled bath, at present, require only a 30-in. by 20-in. tabletop area. The calorimeter is operated from a laptop computer system using unique measurement module capable of monitoring all necessary calorimeter signals. The calorimeter can be operated in the normal calorimeter equilibration mode, as a comparison instrument, using twin chambers and an external electrical calibration method. The sample chamber is 0.75 in (1.9 cm) in diameter by 2.5 in. (6.35 cm) long. This size will accommodate most {sup 238}Pu heat standards manufactured in the past. The power range runs from 0.001 W to <20 W. The high end is only limited by sample size.

  18. Observations of the spectral dependence of linear particle depolarization ratio of aerosols using NASA Langley airborne High Spectral Resolution Lidar

    NASA Astrophysics Data System (ADS)

    Burton, S. P.; Hair, J. W.; Kahnert, M.; Ferrare, R. A.; Hostetler, C. A.; Cook, A. L.; Harper, D. B.; Berkoff, T. A.; Seaman, S. T.; Collins, J. E.; Fenn, M. A.; Rogers, R. R.

    2015-12-01

    Linear particle depolarization ratio is presented for three case studies from the NASA Langley airborne High Spectral Resolution Lidar-2 HSRL-2). Particle depolarization ratio from lidar is an indicator of non-spherical particles and is sensitive to the fraction of non-spherical particles and their size. The HSRL-2 instrument measures depolarization at three wavelengths: 355, 532, and 1064 nm. The three measurement cases presented here include two cases of dust-dominated aerosol and one case of smoke aerosol. These cases have partial analogs in earlier HSRL-1 depolarization measurements at 532 and 1064 nm and in literature, but the availability of three wavelengths gives additional insight into different scenarios for non-spherical particles in the atmosphere. A case of transported Saharan dust has a spectral dependence with a peak of 0.30 at 532 nm with smaller particle depolarization ratios of 0.27 and 0.25 at 1064 and 355 nm, respectively. A case of aerosol containing locally generated wind-blown North American dust has a maximum of 0.38 at 1064 nm, decreasing to 0.37 and 0.24 at 532 and 355 nm, respectively. The cause of the maximum at 1064 nm is inferred to be very large particles that have not settled out of the dust layer. The smoke layer has the opposite spectral dependence, with the peak of 0.24 at 355 nm, decreasing to 0.09 and 0.02 at 532 and 1064 nm, respectively. The depolarization in the smoke case may be explained by the presence of coated soot aggregates. We note that in these specific case studies, the linear particle depolarization ratio for smoke and dust-dominated aerosol are more similar at 355 nm than at 532 nm, having possible implications for using the particle depolarization ratio at a single wavelength for aerosol typing.

  19. Observations of the spectral dependence of particle depolarization ratio of aerosols using NASA Langley airborne High Spectral Resolution Lidar

    NASA Astrophysics Data System (ADS)

    Burton, S. P.; Hair, J. W.; Kahnert, M.; Ferrare, R. A.; Hostetler, C. A.; Cook, A. L.; Harper, D. B.; Berkoff, T. A.; Seaman, S. T.; Collins, J. E.; Fenn, M. A.; Rogers, R. R.

    2015-09-01

    Particle depolarization ratio is presented for three case studies from the NASA Langley airborne High Spectral Resolution Lidar-2 (HSRL-2). Particle depolarization ratio from lidar is an indicator of non-spherical particles and is sensitive to the fraction of non-spherical particles and their size. The HSRL-2 instrument measures depolarization at three wavelengths: 355, 532, and 1064 nm. The three measurement cases presented here include two cases of dust aerosol and one case of smoke aerosol. These cases have partial analogs in earlier HSRL-1 depolarization measurements at 532 and 1064 nm and in literature, but the availability of three wavelengths gives additional insight into different scenarios for non-spherical particles in the atmosphere. A case of transported Saharan dust has a spectral dependence with a peak of 0.30 at 532 nm with smaller particle depolarization ratios of 0.27 and 0.25 at 1064 and 355 nm, respectively. A case of locally generated wind-blown North American dust has a maximum of 0.38 at 1064 nm, decreasing to 0.37 and 0.24 at 532 and 355 nm, respectively. The cause of the maximum at 1064 nm is inferred to be very large particles that have not settled out of the dust layer. The smoke layer has the opposite spectral dependence, with the peak of 0.24 at 355 nm, decreasing to 0.09 and 0.02 at 532 and 1064 nm. The depolarization in the smoke case is inferred to be due to the presence of coated soot aggregates. We also point out implications for the upcoming EarthCARE satellite, which will measure particle depolarization ratio only at 355 nm. At 355 nm, the particle depolarization ratios for all three of our case studies are very similar, indicating that smoke and dust may be more difficult to separate with EarthCARE measurements than heretofore supposed.

  20. 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.

  1. 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.

  2. 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.

  3. Characterization of Airborne Microbial Communities at a High-Elevation Site and Their Potential To Act as Atmospheric Ice Nuclei▿

    PubMed Central

    Bowers, Robert M.; Lauber, Christian L.; Wiedinmyer, Christine; Hamady, Micah; Hallar, Anna G.; Fall, Ray; Knight, Rob; Fierer, Noah

    2009-01-01

    Bacteria and fungi are ubiquitous in the atmosphere. The diversity and abundance of airborne microbes may be strongly influenced by atmospheric conditions or even influence atmospheric conditions themselves by acting as ice nucleators. However, few comprehensive studies have described the diversity and dynamics of airborne bacteria and fungi based on culture-independent techniques. We document atmospheric microbial abundance, community composition, and ice nucleation at a high-elevation site in northwestern Colorado. We used a standard small-subunit rRNA gene Sanger sequencing approach for total microbial community analysis and a bacteria-specific 16S rRNA bar-coded pyrosequencing approach (4,864 sequences total). During the 2-week collection period, total microbial abundances were relatively constant, ranging from 9.6 × 105 to 6.6 × 106 cells m−3 of air, and the diversity and composition of the airborne microbial communities were also relatively static. Bacteria and fungi were nearly equivalent, and members of the proteobacterial groups Burkholderiales and Moraxellaceae (particularly the genus Psychrobacter) were dominant. These taxa were not always the most abundant in freshly fallen snow samples collected at this site. Although there was minimal variability in microbial abundances and composition within the atmosphere, the number of biological ice nuclei increased significantly during periods of high relative humidity. However, these changes in ice nuclei numbers were not associated with changes in the relative abundances of the most commonly studied ice-nucleating bacteria. PMID:19502432

  4. 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.

  5. Semi-automated structural analysis of high resolution magnetic and gamma-ray spectrometry airborne surveys

    NASA Astrophysics Data System (ADS)

    Debeglia, N.; Martelet, G.; Perrin, J.; Truffert, C.; Ledru, P.; Tourlière, B.

    2005-08-01

    A user-controlled procedure was implemented for the structural analysis of geophysical maps. Local edge segments are first extracted using a suitable edge detector function, then linked into straight discontinuities and, finally, organised in complex boundary lines best delineating geophysical features. Final boundary lines may be attributed by a geologist to lithological contacts and/or structural geological features. Tests of some edge detectors, (i) horizontal gradient magnitude (HGM), (ii) various orders of the analytic signal ( An), reduced to the pole or not, (iii) enhanced horizontal derivative (EHD), (iv) composite analytic signal (CAS), were performed on synthetic magnetic data (with and without noise). As a result of these comparisons, the horizontal gradient appears to remain the best operator for the analysis of magnetic data. Computation of gradients in the frequency domain, including filtering and upward continuation of noisy data, is well-suited to the extraction of magnetic gradients associated to deep sources, while space-domain smoothing and differentiation techniques is generally preferable in the case of shallow magnetic sources, or for gamma-ray spectrometry analysis. Algorithms for edge extraction, segment linking, and line following can be controlled by choosing adequate edge detector and processing parameters which allows adaptation to a desired scale of interpretation. Tests on synthetic and real case data demonstrate the adaptability of the procedure and its ability to produce basic layer for multi-data analysis. The method was applied to the interpretation of high-resolution airborne magnetic and gamma-ray spectrometry data collected in northern Namibia. It allowed the delineation of dyke networks concealed by superficial weathering and demonstrated the presence of lithological variations in alluvial flows. The output from the structural analysis procedure are compatible with standard GIS softwares and enable the geologist to (i) compare

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. High-resolution airborne magnetometry for hydrocarbon exploration: A case study, Wilson County, Texas

    SciTech Connect

    McConnell, T.J.; Phillips, J.D.

    1994-12-31

    Aeromagnetic anomaly surveying has been used extensively for geophysical exploration since just before World War II. Its primary value in hydrocarbon exploration has been for mapping the strong magnetic anomalies of the crystalline magnetic basement rocks to estimate the regional thickness of overlying, potential oil and gas bearing sediments. These basement responses are typically in the amplitude range of 2--200 nanotesla (nT) or gammas. In contrast, High Resolution Aeromagnetic (HRA) surveys specifically target the sedimentary stack where response amplitudes generated are typically in the range of 0.2-2.0 nT. These low intensity anomalies generated within the sediments are related to changes in the magnetic composition of rocks. This will occur when rocks of differing magnetic intensities are juxtaposed across a fault, or at a stratigraphic truncation. With this objective in mind a new high resolution, high sensitivity aeromagnetic survey was conducted over parts of Wilson and Karnes counties in Texas.

  16. 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.

  17. Airborne Transparencies.

    ERIC Educational Resources Information Center

    Horne, Lois Thommason

    1984-01-01

    Starting from a science project on flight, art students discussed and investigated various means of moving in space. Then they made acetate illustrations which could be used as transparencies. The projection phenomenon made the illustrations look airborne. (CS)

  18. 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.

  19. 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.

  20. Highly sensitive genotyping using artificial riboregulator system.

    PubMed

    Narita, Atsushi; Ogawa, Kazumasa; Sando, Shinsuke; Aoyama, Yasuhiro

    2005-01-01

    A molecular-beacon-type riboregulator (mRNA) was applied to multiply catalytic gene sensing. It consists of a reporter gene for firefly protein luciferase and, upstream thereof, a regulator hairpin domain composed of an RBS/anti-RBS stem (RBS = ribosome binding site) and a loop which is complementary to the target. The sensing of target gene, using an unmodified RNA or even dsDNA as a probe with a chemiluminescence output, was demonstrated with a sensitivity at < or = 50 fmol of the target and a single nucleotide resolution.

  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. 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.

  3. 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

  4. 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.

  5. 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.

  6. Airborne High Spectral Resolution Lidar Measurements of Aerosol Distributions and Properties during the NASA DISCOVER-AQ Missions

    NASA Astrophysics Data System (ADS)

    Ferrare, R. A.; Hostetler, C. A.; Hair, J. W.; Scarino, A. J.; Burton, S. P.; Harper, D. B.; Cook, A. L.; Berkoff, T.; Rogers, R. R.; Seaman, S. T.; Fenn, M. A.; Sawamura, P.; Clayton, M.; Mueller, D.; Chemyakin, E.; Anderson, B. E.; Beyersdorf, A. J.; Ziemba, L. D.; Crawford, J. H.

    2015-12-01

    The NASA Langley Research Center airborne High Spectral Resolution Lidars, HSRL-1 and HSRL-2, were deployed for the DISCOVER-AQ (Deriving Information on Surface Conditions from COlumn and VERtically Resolved Observations Relevant to Air Quality) missions. DISCOVER-AQ provided systematic and concurrent observations of column-integrated, surface, and vertically-resolved distributions of aerosols and trace gases to improve the interpretation of satellite observations related to air quality. HSRL-1, deployed during the first DISCOVER-AQ mission over the Washington DC-Baltimore region, measured profiles of aerosol backscatter and depolarization (532, 1064 nm) and aerosol extinction and optical thickness (AOT) (532 nm). HSRL-2, the first airborne multiwavelength HSRL, was deployed for the following three DISCOVER-AQ missions over the California Central Valley, Houston, and Denver. HSRL-2 measures profiles of aerosol backscatter and depolarization (355, 532, 1064 nm) and aerosol extinction and AOT (355, 532 nm). Additional HSRL-2 data products include aerosol type, mixed layer depth, and range-resolved aerosol microphysical parameters. The HSRL measurements reveal the temporal, spatial, and vertical variability of aerosol optical properties over these locations. HSRL measurements show that surface PM2.5 concentrations were better correlated with near surface aerosol extinction than AOT scaled by the mixed layer height. During the missions over Washington DC-Baltimore, Houston, and Denver, only about 20-65% of AOT was within the mixed layer. In contrast, nearly all of the AOT was within the mixed layer over the California Central Valley. HSRL-2 retrievals of aerosol fine mode volume concentration and effective radius compare well with coincident airborne in situ measurements and vary with relative humidity. HSRL-2 retrievals of aerosol fine mode volume concentration were also used to derive PM2.5 concentrations which compare well with surface PM2.5 measurements.

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

    PubMed

    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

  8. 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.

  9. 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.

  10. Use of high-performance liquid chromatography to assess airborne mycotoxins. Aflatoxins and ochratoxin A.

    PubMed

    Tarín, A; Rosell, M G; Guardino, X

    2004-08-27

    An HPLC analytical method combining methanol-deionised water (80:20, v/v) extraction, methanol-acetonitrile (50:50, v/v) extraction and fluorescence detection was implanted to analyse ochratoxin A and aflatoxins B1, B2, G1 and G2 of air samples collected during the usual production process in a number of workplaces of a coffee factory to assess the occupational exposure of the engaged workers. The average levels of airborne ochratoxin A and aflatoxins were less than 1.2 and 0.4 ng/m3, respectively, using 50 L air samples. When 150 L air samples were used, levels lower than 0.04 ng/m3 ochratoxin A and 0.013 ng/m3 for aflatoxins B1, B2, G1 and G2, could be detected.

  11. 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.

  12. 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.

  13. 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.

  14. Airborne Imagery

    NASA Technical Reports Server (NTRS)

    1983-01-01

    ATM (Airborne Thematic Mapper) was developed for NSTL (National Space Technology Companies) by Daedalus Company. It offers expanded capabilities for timely, accurate and cost effective identification of areas with prospecting potential. A related system is TIMS, Thermal Infrared Multispectral Scanner. Originating from Landsat 4, it is also used for agricultural studies, etc.

  15. The Sensitivity of a Volcanic Flow Model to Digital Elevation Models From Diverse Sources: Digitized Map Contours and Airborne Interferometric Radar

    NASA Astrophysics Data System (ADS)

    Stevens, N. F.; Manville, V.; Heron, D. W.

    2001-12-01

    A growing trend in the field of volcanic hazard assessment is the use of computer models of a variety of flows to predict potential areas of devastation. The accuracy of these computer models depends on two factors, the nature and veracity of the flow model itself, and the accuracy of the topographic data set over which it is run. All digital elevation models (DEMs) contain innate errors. The nature of these depends on the accuracy of the original measurements of the terrain, and on the method used to build the DEM. We investigate the effect that these errors have on the performance of a simple volcanic flow model designed to delineate areas at risk from lahar inundation. The volcanic flow model was run over two DEMs of southern Ruapehu volcano derived from (1) digitized 1:50,000 topographic maps, and (2) airborne C-band synthetic aperture radar interferometry obtained using the NASA AIRSAR system. On steep slopes (exceeding 4 degrees), drainage channels are more likely to be incised deeply, and flow paths predicted by the model are generally in agreement for both DEMs despite the differing nature of the source data. Over shallow slopes (approx. 4 degrees and less), where channels are less deep and are more likely to meander, problems were encountered with flow path prediction in both DEMs due to interpolation errors and forestry. The predicted lateral and longitudinal extent of deposit inundation was also sensitive to the type of DEM used, most likely in response to the differing degrees of surface texture preserved in the DEMs. A technique to refine contour-derived DEMs and reduce the error in predicted flow paths was tested to improve the reliability of the modeled flow path predictions. The suitability of forthcoming topographic measurements acquired by a single-pass space-borne instrument, the NASA Shuttle Radar Topography Mission (SRTM) are also tested.

  16. 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.

  17. 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

  18. 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

  19. Design optimization of high pressure and high temperature piezoresistive pressure sensor for high sensitivity

    NASA Astrophysics Data System (ADS)

    Niu, Zhe; Zhao, Yulong; Tian, Bian

    2014-01-01

    This paper describes a design method for optimizing sensitivity of piezoresistive pressure sensor in high-pressure and high-temperature environment. In order to prove the method, a piezoresistive pressure sensor (HPTSS) is designed. With the purpose of increasing sensitivity and to improve the measurement range, the piezoresistive sensor adopts rectangular membrane and thick film structure. The configuration of piezoresistors is arranged according to the characteristic of the rectangular membrane. The structure and configuration of the sensor chip are analyzed theoretically and simulated by the finite element method. This design enables the sensor chip to operate in high pressure condition (such as 150 MPa) with a high sensitivity and accuracy. The silicon on insulator wafer is selected to guarantee the thermo stability of the sensor chip. In order to optimize the fabrication and improve the yield of production, an electric conduction step is devised. Series of experiments demonstrates a favorable linearity of 0.13% and a high accuracy of 0.48%. And the sensitivity of HTPSS is about six times as high as a conventional square-membrane sensor chip in the experiment. Compared with the square-membrane pressure sensor and current production, the strength of HPTTS lies in sensitivity and measurement. The performance of the HPTSS indicates that it could be an ideal candidate for high-pressure and high-temperature sensing in real application.

  20. Design optimization of high pressure and high temperature piezoresistive pressure sensor for high sensitivity.

    PubMed

    Niu, Zhe; Zhao, Yulong; Tian, Bian

    2014-01-01

    This paper describes a design method for optimizing sensitivity of piezoresistive pressure sensor in high-pressure and high-temperature environment. In order to prove the method, a piezoresistive pressure sensor (HPTSS) is designed. With the purpose of increasing sensitivity and to improve the measurement range, the piezoresistive sensor adopts rectangular membrane and thick film structure. The configuration of piezoresistors is arranged according to the characteristic of the rectangular membrane. The structure and configuration of the sensor chip are analyzed theoretically and simulated by the finite element method. This design enables the sensor chip to operate in high pressure condition (such as 150 MPa) with a high sensitivity and accuracy. The silicon on insulator wafer is selected to guarantee the thermo stability of the sensor chip. In order to optimize the fabrication and improve the yield of production, an electric conduction step is devised. Series of experiments demonstrates a favorable linearity of 0.13% and a high accuracy of 0.48%. And the sensitivity of HTPSS is about six times as high as a conventional square-membrane sensor chip in the experiment. Compared with the square-membrane pressure sensor and current production, the strength of HPTTS lies in sensitivity and measurement. The performance of the HPTSS indicates that it could be an ideal candidate for high-pressure and high-temperature sensing in real application.

  1. 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.

  2. 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.

  3. 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

  4. A high-sensitivity neutron counter and waste-drum counting with the high-sensitivity neutron instrument

    SciTech Connect

    Hankins, D.E.; Thorngate, J.H.

    1993-04-01

    At Lawrence Livermore National Laboratory (LLNL), a highly sensitive neutron counter was developed that can detect and accurately measure the neutrons from small quantities of plutonium or from other low-level neutron sources. This neutron counter was originally designed to survey waste containers leaving the Plutonium Facility. However, it has proven to be useful in other research applications requiring a high-sensitivity neutron instrument.

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. Source Attribution of Methane Emission from Petroleum Production Operations using High-Resolution Airborne Thermal-Infrared Imaging Spectrometry

    NASA Astrophysics Data System (ADS)

    Tratt, D. M.; Buckland, K. N.; Young, S. J.; Riley, D.; Leifer, I.

    2012-12-01

    High spatio-spectral resolution airborne thermal-infrared (TIR) imaging spectrometry is shown to be effective in detecting and tracking gaseous emissions from petroleum production facilities. The high spatial resolution (1-2 m) of the sensor permits unequivocal trace-back of emission plumes to their source. The high spectral resolution (44 nm across the 7.5-13.5 μm TIR band) enables precise identification and discrimination of primary and subsidiary plume components through the application of spectral matched filtering and adaptive coherence estimation techniques. Operation in the TIR spectral region allows operations to be conducted throughout the diurnal cycle, since the measurement relies on observation of emissive radiation and the intrinsic thermal contrast between the fugitive plume gases and the underlying scene. Methane plumes associated with petroleum production operations and natural emissions have been identified in a variety of environmental settings. The accompanying figure shows a grayscale thermal image of a marine production platform off the California coast. A gas plume (identified as methane) being released from a venting boom is shown superimposed in false color.

  10. 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.

  11. 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.

  12. 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

  13. Highly sensitive tactile sensors integrated with organic transistors

    NASA Astrophysics Data System (ADS)

    Kim, Jiseok; Nga Ng, Tse; Soo Kim, Woo

    2012-09-01

    This paper presents a highly sensitive capacitive pressure sensor composed of a polymer dielectric film with a nano-needle structure. The nano-needle polymer films were prepared by facile fabrication methods including breath figures formation followed by stamping. The pressure sensitivity of the sensor reached 1.76 kPa-1 in the low pressure range (<1 kPa), which is comparable to the sensitivity of human skin. Analysis of the geometries and densities effect was shown, and the nano-needle film showed better sensitivity in comparison to films with hemispherical or conical structures. The pressure sensors were integrated with printed organic thin film transistors to enable flexible, large-area tactile sensing applications.

  14. Liquid-phase sample preparation method for real-time monitoring of airborne asbestos fibers by dual-mode high-throughput microscopy.

    PubMed

    Cho, Myoung-Ock; Kim, Jung Kyung; Han, Hwataik; Lee, Jeonghoon

    2013-01-01

    Asbestos that had been used widely as a construction material is a first-level carcinogen recognized by the World Health Organization. It can be accumulated in body by inhalation causing virulent respiratory diseases including lung cancer. In our previous study, we developed a high-throughput microscopy (HTM) system that can minimize human intervention accompanied by the conventional phase contrast microscopy (PCM) through automated counting of fibrous materials and thus significantly reduce analysis time and labor. Also, we attempted selective detection of chrysotile using DksA protein extracted from Escherichia coli through a recombinant protein production technique, and developed a dual-mode HTM (DM-HTM) by upgrading the HTM device. We demonstrated that fluorescently-labeled chrysotile asbestos fibers can be identified and enumerated automatically among other types of asbestos fibers or non-asbestos particles in a high-throughput manner through a newly modified HTM system for both reflection and fluorescence imaging. However there is a limitation to apply DM-HTM to airborne sample with current air collecting method due to the difficulty of applying the protein to dried asbestos sample. Here, we developed a technique for preparing liquid-phase asbestos sample using an impinger normally used to collect odor molecules in the air. It would be possible to improve the feasibility of the dual-mode HTM by integrating a sample preparation unit for making collected asbestos sample dispersed in a solution. The new technique developed for highly sensitive and automated asbestos detection can be a potential alternative to the conventional manual counting method, and it may be applied on site as a fast and reliable environmental monitoring tool.

  15. A sensitive and high dynamic range cw laser power meter

    NASA Astrophysics Data System (ADS)

    Krishnan, S.; Bindra, K. S.; Oak, S. M.

    2008-12-01

    We report the design of a cost effective, highly sensitive cw laser power meter with a large dynamic range based on a photodiode. The power meter consists of a photodiode, a current to voltage converter circuit, an offset balancing circuit, a microcontroller, an analog to digital converter, reed relays, and an alphanumeric liquid crystal display. The power meter can record absolute laser power levels as low as 1 pW. The dynamic range measured with a cw laser at a wavelength of 532 nm is 8×1010. The high sensitivity and large dynamic range are achieved by the implementation of an analog background balancing circuit and autoranging.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. Routing architecture and security for airborne networks

    NASA Astrophysics Data System (ADS)

    Deng, Hongmei; Xie, Peng; Li, Jason; Xu, Roger; Levy, Renato

    2009-05-01

    Airborne networks are envisioned to provide interconnectivity for terrestial and space networks by interconnecting highly mobile airborne platforms. A number of military applications are expected to be used by the operator, and all these applications require proper routing security support to establish correct route between communicating platforms in a timely manner. As airborne networks somewhat different from traditional wired and wireless networks (e.g., Internet, LAN, WLAN, MANET, etc), security aspects valid in these networks are not fully applicable to airborne networks. Designing an efficient security scheme to protect airborne networks is confronted with new requirements. In this paper, we first identify a candidate routing architecture, which works as an underlying structure for our proposed security scheme. And then we investigate the vulnerabilities and attack models against routing protocols in airborne networks. Based on these studies, we propose an integrated security solution to address routing security issues in airborne networks.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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

  7. [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.

  8. Sensitivity of high-frequency Rayleigh-wave data revisited

    USGS Publications Warehouse

    Xia, J.; Miller, R.D.; Ivanov, J.

    2007-01-01

    Rayleigh-wave phase velocity of a layered earth model is a function of frequency and four groups of earth properties: P-wave velocity, S-wave velocity (Vs), density, and thickness of layers. Analysis of the Jacobian matrix (or the difference method) provides a measure of dispersion curve sensitivity to earth properties. Vs is the dominant influence for the fundamental mode (Xia et al., 1999) and higher modes (Xia et al., 2003) of dispersion curves in a high frequency range (>2 Hz) followed by layer thickness. These characteristics are the foundation of determining S-wave velocities by inversion of Rayleigh-wave data. More applications of surface-wave techniques show an anomalous velocity layer such as a high-velocity layer (HVL) or a low-velocity layer (LVL) commonly exists in near-surface materials. Spatial location (depth) of an anomalous layer is usually the most important information that surface-wave techniques are asked to provide. Understanding and correctly defining the sensitivity of high-frequency Rayleigh-wave data due to depth of an anomalous velocity layer are crucial in applying surface-wave techniques to obtain a Vs profile and/or determine the depth of an anomalous layer. Because depth is not a direct earth property of a layered model, changes in depth will result in changes in other properties. Modeling results show that sensitivity at a given depth calculated by the difference method is dependent on the Vs difference (contrast) between an anomalous layer and surrounding layers. The larger the contrast is, the higher the sensitivity due to depth of the layer. Therefore, the Vs contrast is a dominant contributor to sensitivity of Rayleigh-wave data due to depth of an anomalous layer. Modeling results also suggest that the most sensitive depth for an HVL is at about the middle of the depth to the half-space, but for an LVL it is near the ground surface. ?? 2007 Society of Exploration Geophysicists.

  9. 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.

  10. 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

  11. Discrimination of airborne radioactivity from radon progeny

    SciTech Connect

    Ching-Jiang Chen; Pao-Shan Weng; Tieh-Chi Chu

    1994-05-01

    Naturally occurring radon and thoron progeny are the most interfering nuclides in the aerosol monitoring system. The high background and fluctuation of natural radioactivity on the filter can cause an error message to the aerosol monitor. A theoretical model was applied in the simulation of radon and thoron progeny behavior in the environment and on the filter. Results show that even a small amount of airborne nuclides on the filter could be discriminated by using the beta:alpha activity ratio instead of gross beta or alpha counting. This method can increase the sensitivity and reliability of real-time aerosol monitoring. 8 refs., 11 figs., 3 tabs.

  12. 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.

  13. Highly Mass-Sensitive Thin Film Plate Acoustic Resonators (FPAR)

    PubMed Central

    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

  14. 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.

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

    DOE PAGES

    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.

  16. 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.

  17. Single-pass Airborne InSAR for Wide-swath, High-Resolution Cryospheric Surface Topography Mapping

    NASA Astrophysics Data System (ADS)

    Moller, D.; Hensley, S.; Wu, X.; Muellerschoen, R.

    2014-12-01

    In May 2009 a mm-wave single-pass interferometric synthetic aperture radar (InSAR) for the first time demonstrated ice surface topography swath-mapping in Greenland. This was achieved with the airborne Glacier and Ice Surface Topography Interferometer (GLISTIN-A). Ka-band (35.6GHz) was chosen for high-precision topographic mapping from a compact sensor with minimal surface penetration. In recent years, the system was comprehensively upgraded for improved performance, stability and calibration. In April 2013, after completing the upgrades, GLISTIN-A flew a brief campaign to Alaska. The primary purpose was to demonstrate the InSAR's ability to generate high-precision, high resolution maps of ice surface topography with swaths in excess of 10km. Comparison of GLISTIN-A's elevations over glacial ice with lidar verified the precision requirements and established elevation accuracies to within 2 m without tie points. Feature tracking of crevasses on Columbia Glacier using data acquired with a 3-day separation exhibit an impressive velocity mapping capability. Furthermore, GLISTIN-A flew over the Beaufort sea to determine if we could not only map sea ice, but also measure freeboard. Initial analysis has established we can measure sea-ice freeboard using height differences from the top of the sea-ice and the sea surface in open leads. In the future, a campaign with lidar is desired for a quantitative validation. Another proof-of-concept collection mapped snow-basins for hydrology. Snow depth measurements using summer and winter collections in the Sierras were compared with lidar measurements. Unsurprisingly when present, trees complicate the interpretation, but additional filtering and processing is in work. For each application, knowledge of the interferometric penetration is important for scientific interpretation. We present analytical predictions and experimental data to upper bound the elevation bias of the InSAR measurements over snow and snow-covered ice.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. NETD test of high-sensitivity infrared camera

    NASA Astrophysics Data System (ADS)

    Li, Yingwen; Pan, Debin; Yang, Changcheng; Luo, Yan

    2007-12-01

    Infrared camera has more and more application in military, judicature, rescue, industry, hospital and science. Nowadays the NETD (Noise Equivalent Temperature Difference) of high-sensitivity cooled infrared camera is less than 10 mK. If we test the NETD from the analog video output port of infrared camera using 8-bit and 10-bit ADC frame grabber, the NETD accuracy is 7.81 mK and 2.76 mK which correspond to relative error 78.7% and 27.6% for a 10 mK NETD infrared camera. Such kind of accuracy is obviously not proper for the performance evaluation of high-sensitivity infrared camera with NETD less than 10 mK. The NETD test accuracy can be improved by increasing the effective bit number of the ADC of frame grabber. The quantization error of ADC of frame grabber has become the main factor which contributes most to the NETD error of the high-sensitivity infrared camera. It is difficult to evaluate the electrooptical performance of the high-sensitivity infrared camera through its analog video. Although the NETD test accuracy can be improved by reducing the linear temperature range or increasing the effective bits of the ADC of frame grabber under analog video interface test condition, it is difficult to meet the test needs. But under the 14 bits digital video interface test condition and 1 K linear range, the NETD test accuracy of 0.24 mK can be achieved. The NETD accuracy can be also improved by reducing the linear temperature range. The NETD test accuracy can be 0.488 mK through 14-bit digital video under 2 K linear temperature range and its relative error equals 4.9% for a 10 mK NETD high-sensitivity infrared camera which meets the requirement. The test result through the digital video port of an infrared camera shows that the test result through digital video port matches with its nominal value. This necessitates the need of digital video interface of high-sensitivity infrared camera in NETD test in order to evaluate its performance accuracy.

  7. 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.

  8. 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 ...

  9. Airborne fission products in the High Arctic after the Fukushima nuclear accident.

    PubMed

    Paatero, Jussi; Vira, Julius; Siitari-Kauppi, Marja; Hatakka, Juha; Holmén, Kim; Viisanen, Yrjö

    2012-12-01

    High-volume aerosol samples were collected at the Mt. Zeppelin Global Atmosphere Watch station, Ny-Ålesund, Svalbard (78°58'N, 11°53'E). The samples were analysed to find out if the radionuclide emissions from the Fukushima nuclear power plant accident in March 2011 could be detected also in the atmosphere of the High Arctic. Iodine-131 and (134)Cs and (137)Cs were observed from 25 March 2011 onwards. The maximum (131)I, (134)Cs and (137)Cs activity concentrations were 810 ± 20, 659 ± 13, and 675 ± 7 μBq/m(3), respectively. The comparison between the measured (131)I activity concentrations at Mt. Zeppelin and those calculated with the SILAM dispersion model revealed that the timing of plume movements could be rather well predicted with the model. The activity concentration levels between the measurements and the model calculations deviated. This can be due to the inaccuracies in the source term. The (134)Cs:(137)Cs activity ratio recorded in Svalbard was high compared to earlier incidents. The ratio was close to 1 which is in agreement with other studies of the Fukushima releases. This distinctive activity ratio in the Fukushima debris could be used as a tracer in Arctic radioecology studies if the activity concentrations are high enough to be detected.

  10. 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...

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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

  17. 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.

  18. [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

  19. 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.

  20. 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

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

    PubMed

    Monaghan, Jessica J M; 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

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. High-volume sampling of airborne polycyclic aromatic hydrocarbons using glass fibre filters and polyurethane foam

    NASA Astrophysics Data System (ADS)

    Thrane, K. E.; Mikalsen, A.

    A sampling system for collection of polycyclic aromatic hydrocarbons (PAH) in air is described. PAH were collected on glass fibre filters and plugs of polyurethane (PUR) foam by high-volume sampling. The analyses were carried out by high-resolution gas chromatography. The efficiency of these filter media has been investigated, and polyurethane foam seems to be efficient for the collection of selected PAH. The system has been used for PAH measurements in background, suburban and urban areas for average concentrations ranging from 20 to about 1500 ng m -3. A comparison of the profiles of PAH species obtained at the different locations shows that they are similar, and also that the relative concentrations of some of the compounds vary within only a few per cent. The distributions of the gas phase PAH found on the PUR plugs and in the particles collected on the glass fibre filters, correspond well with the results of a study on the gas-aerosol equilibrium made in Belgium.

  8. Multi-stage robust scheme for citrus identification from high resolution airborne images

    NASA Astrophysics Data System (ADS)

    Amorós-López, Julia; Izquierdo Verdiguier, Emma; Gómez-Chova, Luis; Muñoz-Marí, Jordi; Zoilo Rodríguez-Barreiro, Jorge; Camps-Valls, Gustavo; Calpe-Maravilla, Javier

    2008-10-01

    Identification of land cover types is one of the most critical activities in remote sensing. Nowadays, managing land resources by using remote sensing techniques is becoming a common procedure to speed up the process while reducing costs. However, data analysis procedures should satisfy the accuracy figures demanded by institutions and governments for further administrative actions. This paper presents a methodological scheme to update the citrus Geographical Information Systems (GIS) of the Comunidad Valenciana autonomous region, Spain). The proposed approach introduces a multi-stage automatic scheme to reduce visual photointerpretation and ground validation tasks. First, an object-oriented feature extraction process is carried out for each cadastral parcel from very high spatial resolution (VHR) images (0.5m) acquired in the visible and near infrared. Next, several automatic classifiers (decision trees, multilayer perceptron, and support vector machines) are trained and combined to improve the final accuracy of the results. The proposed strategy fulfills the high accuracy demanded by policy makers by means of combining automatic classification methods with visual photointerpretation available resources. A level of confidence based on the agreement between classifiers allows us an effective management by fixing the quantity of parcels to be reviewed. The proposed methodology can be applied to similar problems and applications.

  9. 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.

  10. 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.

  11. 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.

  12. Monitoring airborne dust in a high density coal-fired power station region in North Yorkshire.

    PubMed

    Vallack, H W; Chadwick, M J

    1993-01-01

    Concerns about the levels of dust deposition in the vicinity of coal-fired power stations in North Yorkshire, in particular Drax Power Station, prompted the commissioning of a detailed monitoring study in the area. This paper describes the first two years' work. The first 12-month study concentrated on the village of Barlow close to Drax Power Station, whilst in the second 12-month study, monitoring sites were spread along a transect passing through the power station belt formed by Ferrybridge, Eggborough and Drax Power Stations. Two monitoring sites were common to both 12-month studies, thus giving two years of continuous monitoring. Pairs of wet Frisbee dust deposit gauges (based on inverted Frisbees) were located at each site. Undissolved particulate matter from each gauge was weighed and characterized by microscopic examination of individual particles. The first 12-month study revealed a downward gradient in dust deposition rate and cenosphere content with distance from Drax Power Station. The high cenosphere content at Barlow, especially at the eastern end, suggested that there was a significant contribution from coal-fired power stations. In the second year, the overall pattern of dust deposition rate and cenosphere content across the power station belt suggested that power stations were contributing to higher levels. In particular, relatively high levels were again found at Barlow. Wind direction correlations point to the fly-ash tip next to Drax Power Station as being the source of cenospheres arriving at Barlow. It is concluded that in both years the fly-ash tip Drax Power Station was making a significant contribution to higher than expected dust deposition rates at Barlow, particularly its eastern end. Other villages in the area may also have been affected by dust originating from coal-fired power stations.

  13. 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.

  14. 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

  15. Development of a highly sensitive galvanic cell oxygen sensor.

    PubMed

    Ogino, H; Asakura, K

    1995-02-01

    A highly sensitive galvanic cell oxygen sensor was successfully developed for determining parts per billion of oxygen in high purity gases such as nitrogen, argon, etc. The response of this improved sensor was proportional in the range of oxygen concentrations from 10.0 ppm to the detection limit. The response speed in this study was improved to within 90 sec for a 90% response. The detection limit was tentatively found to be less than 0.4 ppb corresponding to S N = 2 .

  16. 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.

  17. 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.

  18. 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.

  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.

  20. 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.

  1. High sensitivity, homogeneous particle-based immunoassay for thyrotropin (Multipact).

    PubMed

    Wilkins, T A; Brouwers, G; Mareschal, J C; Cambiaso, C L

    1988-09-01

    We describe the first homogeneous, nonradioactive, high-sensitivity assay for human thyrotropin (TSH). The assay is based on particle immunoassay techniques, wherein 800-nm particles form the basis for the immunochemistry, delivery, and the detection technologies, respectively. Our assay also is the first to involve the use of fragmented monoclonal antibodies (to eliminate serum interferences) covalently coupled to particles without loss of their binding properties. Assays are performed in a semiautomated mode with use of a new modular system (Multipact). Equilibrium is reached in less than 2 h. Precision profile, sensitivity, and clinical studies indicate that the assay is accurate, has good precision at low concentrations, and that detection-limit characteristics compare well with those of a leading commercial high-sensitivity immunoradiometric assay (IRMA) for TSH. Dilution characteristics were satisfactory down to the assay's detection limit for a range of clinical samples. Correlation studies vs a reference IRMA method yielded the regression equation, present method = 0.976 (IRMA) + 0.002 milli-int. unit/L (r = 0.98), for 223 samples with TSH concentrations in the range 0 to 30 milli-int. units/L. For 40 samples with TSH less than or equal to 1.0 milli-int. unit/L it was: present method = 0.94 (IRMA) + 0.005 milli-int. unit/L (r = 0.96). PMID:3416423

  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. 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

  4. Evaluation of the NASA Langley Research Center airborne High Spectral Resolution Lidar extinction measurements during the Megacity Initiative: Local and Global Research Observations (MILAGRO) Campaign

    NASA Astrophysics Data System (ADS)

    Rogers, R. R.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. W.; Cook, A. L.; Harper, D. B.; Obland, M. D.; Burton, S. P.; Clarke, A. D.; Russell, P. B.; Redemann, J.; Livingston, J. M.

    2007-12-01

    The NASA Langley Research Center (LaRC) airborne High Spectral Resolution Lidar (HSRL) was deployed on the NASA LaRC B-200 King Air aircraft and measured profiles of aerosol extinction, backscatter, and depolarization during the Megacity Initiative: Local and Global Research Observations (MILAGRO) Campaign in March 2006. The HSRL collected approximately 55 hours of data over 15 science flights, which were coordinated with the Sky Research J-31 aircraft (5 flights), the DOE G-1 aircraft (6 flights), and the NCAR C-130 aircraft (4 flights). This coordinated effort in MILAGRO provides the first opportunity to evaluate the HSRL aerosol extinction and optical thickness profiles with corresponding profiles derived from the other airborne measurements: 1) the 14 channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) on the J-31 and the in situ nephelometer measurements of aerosol scattering and Particle Soot Absorption Photometer (PSAP) measurements of aerosol absorption from the Hawaii Group for Environment and Atmospheric Research (HiGEAR) on the C-130. This study will include comparisons of aerosol extinction from these three techniques in cases where the HSRL flew directly over the AATS-14 and HiGEAR instruments while they measured aerosol extinction profiles. The results are used in assessing the uncertainty of the HSRL extinction profiles. Column aerosol optical depth (AOD) derived from the HSRL measurements is also compared with AOD derived from Moderate Resolution Imaging Spectroradiometer (MODIS) measurements acquired on the Terra and Aqua spacecraft and from Aerosol Robotic Network (AERONET) ground-based Sun photometer measurements.

  5. 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.

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

    PubMed

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

    2016-04-16

    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.

  7. Sensitivity to Error Fields in NSTX High Beta Plasmas

    SciTech Connect

    Park, Jong-Kyu; Menard, Jonathan E.; Gerhardt, Stefan P.; Buttery, Richard J.; Sabbagh, Steve A.; Bell, Steve E.; LeBlanc, Benoit P.

    2011-11-07

    It was found that error field threshold decreases for high β in NSTX, although the density correlation in conventional threshold scaling implies the threshold would increase since higher β plasmas in our study have higher plasma density. This greater sensitivity to error field in higher β plasmas is due to error field amplification by plasmas. When the effect of amplification is included with ideal plasma response calculations, the conventional density correlation can be restored and threshold scaling becomes more consistent with low β plasmas. However, it was also found that the threshold can be significantly changed depending on plasma rotation. When plasma rotation was reduced by non-resonant magnetic braking, the further increase of sensitivity to error field was observed.

  8. High derivatives for fast sensitivity analysis in linear magnetodynamics

    SciTech Connect

    Petin, P. |; Coulomb, J.L.; Conraux, P.

    1997-03-01

    In this article, the authors present a method of sensitivity analysis using high derivatives and Taylor development. The principle is to find a polynomial approximation of the finite elements solution towards the sensitivity parameters. While presenting the method, they explain why this method is applicable with special parameters only. They applied it on a magnetodynamic problem, simple enough to be able to find the analytical solution with a formal calculus tool. They then present the implementation and the good results obtained with the polynomial, first by comparing the derivatives themselves, then by comparing the approximate solution with the theoretical one. After this validation, the authors present results on a real 2D application and they underline the possibilities of reuse in other fields of physics.

  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. 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

  11. 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

  12. 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.

  13. High-sensitivity uncooled microcantilever infrared imaging arrays

    NASA Astrophysics Data System (ADS)

    Hunter, Scott R.; Maurer, Gregory; Jiang, Lijun; Simelgor, Gregory

    2006-05-01

    The design and operation of an advanced bimorph microcantilever based infrared imaging detector are presented. This technology has the potential to achieve very high sensitivities due to its inherent high responsivity and low noise sensor and detection electronics. The sensor array is composed of bimaterial, thermally sensitive microcantilever structures that are the moving elements of variable plate capacitors. The heat sensing microcantilever structures are integrated with CMOS control and amplification electronics to produce a low cost imager that is compatible with standard silicon IC foundry processing and materials. The bimorph sensor structure is fabricated using low thermal expansion, high thermal isolation silicon oxide and oxynitride materials, and a high thermal expansion aluminum alloy bimetal. The microcantilever paddle is designed to move away from the substrate at elevated imaging temperatures, leading to large modeled sensor dynamic ranges (~16 bits). A temperature coefficient of capacitance, ▵C/C, (equivalent to TCR for microbolometers) above 30% has been modeled and measured for these structures, leading to modeled NEDT < 20 mK and thermal time constants in the 5-10 msec range giving a figure-of-merit [1] NEDT.Tau = 100-200 mK.msec. The development efforts to date have focused on the fabrication of 160x120 pixel arrays with 50 micron pitch pixels. Results from detailed thermo-electro-opto-mechanical modeling of the operation of these sensors are compared with experimental measurements from various test and integrated sensor structures and arrays.

  14. [Highly sensitive detection technology for biological toxins applying sugar epitopes].

    PubMed

    Uzawa, Hirotaka

    2009-01-01

    The Shiga toxin is a highly poisonous protein produced by enterohemorrhagic Escherichia coli O157. This bacterial toxin causes the hemolytic uremic syndrome. Another plant toxin from castor beans, ricin, is also highly toxic. The toxin was used for assassination in London. Recently, there were several cases of postal matter containing ricin. Both toxins are categorized as biological warfare agents by the Centers of Disease Control and Prevention. Conventional detection methods based on the antigen-antibody reaction, PCR and other cell-free assays have been proposed. However, those approaches have drawbacks in terms of sensitivity, analytical time, or stability of the detection reagents. Therefore, development of a facile and sensitive detection method is essential. Here we describe new detection methods applying carbohydrate epitopes as the toxin ligands, which is based on the fact that the toxins bind cell-surface oligosaccharides. Namely, the Shiga toxin has an affinity for globobiosyl (Gb(2)) disaccharide, and ricin binds the beta-D-galactose residue. For Shiga toxin detection, surface plasmon resonance (SPR) was applied. A polyanionic Gb(2)-glycopolymer was designed for this purpose, and it was used for the assembly of Gb(2)-chips using alternating layer-by-layer technology. The method allowed us to detect the toxin at a low concentration of LD(50). A synthetic carbohydrate ligand for ricin was designed and immobilized on the chips. SPR analysis with the chips allows us to detect ricin in a highly sensitive and facile manner (10 pg/ml, 5 min). Our present approaches provide a highly effective way to counter bioterrorism.

  15. 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.

  16. 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

  17. 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

  18. Piezoelectric rubber films for highly sensitive impact measurement

    NASA Astrophysics Data System (ADS)

    Wang, Jhih-Jhe; Tsai, Jui-Wei; Su, Yu-Chuan

    2013-07-01

    We have successfully demonstrated the microfabrication of piezoelectric rubber films and their application in impact measurement. To realize the desired piezoelectricity and stretchability, cellular polydimethylsiloxane (PDMS) structures with micrometer-sized voids are internally implanted with bipolar charges, which function as dipoles and respond promptly to electromechanical stimuli. In the prototype demonstration, 300 µm thick cellular PDMS films are fabricated and internally coated with a thin polytetrafluoroethylene (PTFE) layer to secure the implanted charges. Meanwhile, the top and bottom surfaces of the cellular PDMS films are deposited with stretchable gold electrodes. An electric field up to 35 MV m-1 is applied across the gold electrodes to ionize the air in the voids and to implant charges on the inner surfaces. The resulting composite structures behave like rubber (with an elastic modulus of about 300 kPa) and show strong piezoelectricity (with a piezoelectric coefficient d33 higher than 1000 pC N-1). While integrated with a wide bandwidth and large dynamic-range charge amplifier, highly sensitive impact measurement (with a stress sensitivity of about 10 mV Pa-1) is demonstrated. As such, the demonstrated piezoelectric rubber films could potentially serve as a sensitive electromechanical material for low-frequency stimuli, and fulfill the needs of a variety of physiological monitoring and wearable electronics applications.

  19. Position sensitive detection of neutrons in high radiation background field

    SciTech Connect

    Vavrik, D.; Jakubek, J.; Pospisil, S.; Vacik, J.

    2014-01-15

    We present the development of a high-resolution position sensitive device for detection of slow neutrons in the environment of extremely high γ and e{sup −} radiation background. We make use of a planar silicon pixelated (pixel size: 55 × 55 μm{sup 2}) spectroscopic Timepix detector adapted for neutron detection utilizing very thin {sup 10}B converter placed onto detector surface. We demonstrate that electromagnetic radiation background can be discriminated from the neutron signal utilizing the fact that each particle type produces characteristic ionization tracks in the pixelated detector. Particular tracks can be distinguished by their 2D shape (in the detector plane) and spectroscopic response using single event analysis. A Cd sheet served as thermal neutron stopper as well as intensive source of gamma rays and energetic electrons. Highly efficient discrimination was successful even at very low neutron to electromagnetic background ratio about 10{sup −4}.

  20. 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.

  1. 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.

  2. 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

  3. 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

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. Highly sensitive Raman system for dissolved gas analysis in water.

    PubMed

    Yang, Dewang; Guo, Jinjia; Liu, Qingsheng; Luo, Zhao; Yan, Jingwen; Zheng, Ronger

    2016-09-20

    The detection of dissolved gases in seawater plays an important role in ocean observation and exploration. As a potential technique for oceanic applications, Raman spectroscopy has already proved its advantages in the simultaneous detection of multiple species during previous deep-sea explorations. Due to the low sensitivity of conventional Raman measurements, there have been many reports of Raman applications on direct seawater detection in high-concentration areas, but few on undersea dissolved gas detection. In this work, we have presented a highly sensitive Raman spectroscopy (HSRS) system with a special designed gas chamber for small amounts of underwater gas extraction. Systematic experiments have been carried out for system evaluation, and the results have shown that the Raman signals obtained by the innovation of a near-concentric cavity was about 21 times stronger than those of conventional side-scattering Raman measurements. Based on this system, we have achieved a low limit of detection of 2.32 and 0.44  μmol/L for CO2 and CH4, respectively, in the lab. A test-out experiment has also been accomplished with a gas-liquid separator coupled to the Raman system, and signals of O2 and CO2 were detected after 1 h of degasification. This system may show potential for gas detection in water, and further work would be done for the improvement of in situ detection.

  10. 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

  11. 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

  12. High Sensitivity, Low Volume Method to Determine Dissolved Phosphorus

    NASA Astrophysics Data System (ADS)

    Haberer, J. L.; Brandes, J. A.

    2001-12-01

    A high sensitivity, low volume method was developed to determine nanomolar concentrations of soluble reactive phosphorus (SRP) using reverse phase HPLC. The technique in determining SRP involved using methods from Strickland and Parsons, 1972 and Karl and Tien, 1992. Various techniques for improving blanks and sensitivity will be discussed. The method was applied to seawater and freshwater samples taken from the estuarine Nueces Delta system, Texas, two sites in the Gulf of Mexico, and within two upland (2400 m) forest catchments in the Peruvian Andes. One catchment was partially deforested within the last 3 years, while the other has remained untouched. Samples in the Gulf of Mexico were taken at a series of coastal and open water stations at various depths. Samples in each of the two upland forest catchments in Peru were obtained at 33.3 m distance intervals along a 100 m reach. Samples were taken in the Nueces River, Texas upland from a marsh estuary and from high and low regions of the marsh. Comparisons are made between the forest catchment sites in addition to comparisons made in the Nueces marsh estuary/river system. Depth profiles of SRP in the Gulf of Mexico are established. Future studies should be conducted to investigate phosphate in sediment pore waters. This method has many potential applications, is scalable across a wide range of sample volumes, and can be automated.

  13. Highly sensitive Raman system for dissolved gas analysis in water.

    PubMed

    Yang, Dewang; Guo, Jinjia; Liu, Qingsheng; Luo, Zhao; Yan, Jingwen; Zheng, Ronger

    2016-09-20

    The detection of dissolved gases in seawater plays an important role in ocean observation and exploration. As a potential technique for oceanic applications, Raman spectroscopy has already proved its advantages in the simultaneous detection of multiple species during previous deep-sea explorations. Due to the low sensitivity of conventional Raman measurements, there have been many reports of Raman applications on direct seawater detection in high-concentration areas, but few on undersea dissolved gas detection. In this work, we have presented a highly sensitive Raman spectroscopy (HSRS) system with a special designed gas chamber for small amounts of underwater gas extraction. Systematic experiments have been carried out for system evaluation, and the results have shown that the Raman signals obtained by the innovation of a near-concentric cavity was about 21 times stronger than those of conventional side-scattering Raman measurements. Based on this system, we have achieved a low limit of detection of 2.32 and 0.44  μmol/L for CO2 and CH4, respectively, in the lab. A test-out experiment has also been accomplished with a gas-liquid separator coupled to the Raman system, and signals of O2 and CO2 were detected after 1 h of degasification. This system may show potential for gas detection in water, and further work would be done for the improvement of in situ detection. PMID:27661606

  14. 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

  15. Design of a charge sensitive preamplifier on high resistivity silicon

    SciTech Connect

    Radeka, V.; Rehak, P.; Rescia, S.; Gatti, E.; Longoni, A.; Sampietro, M.; Holl, P.; Strueder, L.; Kemmer, J.

    1987-01-01

    A low noise, fast charge sensitive preamplifier was designed on high resistivity, detector grade silicon. It is built at the surface of a fully depleted region of n-type silicon. This allows the preamplifier to be placed very close to a detector anode. The preamplifier uses the classical input cascode configuration with a capacitor and a high value resistor in the feedback loop. The output stage of the preamplifier can drive a load up to 20pF. The power dissipation of the preamplifier is 13mW. The amplifying elements are ''Single Sided Gate JFETs'' developed especially for this application. Preamplifiers connected to a low capacitance anode of a drift type detector should achieve a rise time of 20ns and have an equivalent noise charge (ENC), after a suitable shaping, of less than 50 electrons. This performance translates to a position resolution better than 3..mu..m for silicon drift detectors. 6 refs., 9 figs.

  16. 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.

  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. 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

  19. Coherent Raman Scattering: Methods Towards Imaging with High Sensitivity

    NASA Astrophysics Data System (ADS)

    Bachler, Brandon Richard

    Coherent Raman spectroscopy is a powerful tool for molecular identification. For imaging applications, Raman spectroscopy techniques have offered a way of achieving endogenous chemical contrast without the need for fluorescent labeling. Increasing the sensitivity of Raman scattering microscopy is vital to performing high speed, chemically selective imaging. This thesis presents three experiments with the ultimate goal of increasing the sensitivity and quantifying limitations of different Raman techniques. The first experiment is a comparison of spontaneous and coherent Raman signal strengths under biological imaging conditions. While it is commonly stated in the literature that coherent Raman techniques provide orders of magnitude higher signal than spontaneous Raman, such a comparison has not been done under the low concentration, low excitation power conditions relevant for biological imaging. We determine a critical power above which coherent Raman methods provide higher signal and below which spontaneous Raman methods provide higher sensitivity. Contrary to what is commonly stated in the literature, spontaneous Raman can provide higher signal levels under common biological imaging conditions. The second experiment is a demonstration of the first multiplexed Raman-induced Kerr effect (BIKES) microscopy setup to date. We compare the signal-to-noise ratios between femtosecond stimulated Raman (FSRS) and RIKES for spectroscopy applications in solution and for microscopy applications with polystyrene beads. We find that for our samples, RIKES consistently provides a higher signal-to-noise ratio than FSRS for both applications. We also use RIKES microscopy to map out the distribution of cytoplasm in onion cells. Finally, a surface-enhanced Raman experiment is performed to observe and compare highly enhanced signals for spontaneous and coherent Raman spectroscopy. We use a commercial SERS substrate and observe significantly enhanced spontaneous Raman signals from

  20. 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

  1. 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.

  2. 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

  3. 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

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

    SciTech Connect

    Anstey, Mitchell R.; 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 "Click" 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. 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.

  6. Highly sensitive flow-injection chemiluminescence determination of pyrogallol compounds

    NASA Astrophysics Data System (ADS)

    Kanwal, Shamsa; Fu, Xiaohong; Su, Xingguang

    2009-12-01

    A highly sensitive flow-injection chemiluminescent method for the direct determination of pyrogallol compounds has been developed. Proposed method is based on the enhanced effect of pyrogallol compounds on the chemiluminescence signals of KMnO 4-H 2O 2 system in slightly alkaline medium. Three important pyrogallol compounds, pyrogallic acid, gallic acid and tannic acid, have been detected by this method, and the possible mechanism of the CL reaction is also discussed. The proposed method is simple, convenient, rapid (60 samples h -1), and sensitive, has a linear range of 8 × 10 -10 mol L -1 to 1 × 10 -5 mol L -1, for pyrogallic acid, with a detection limit of 6 × 10 -11 mol L -1, 4 × 10 -8 mol L -1 to 5 × 10 -3 mol L -1 for gallic acid with a detection limit of 9 × 10 -10 mol L -1, and 8 × 10 -8 mol L -1 to 5 × 10 -2 mol L -1 for tannic acid, with a detection limit of 2 × 10 -9 mol L -1, respectively. The relative standard deviation (RSD, n = 15) was 0.8, 1.1 and 1.3% for 5 × 10 -6 mol L -1 pyrogallic acid, gallic acid and tannic acid, respectively. The proposed method was successfully applied to the determination of pyrogallol compounds in tea and coffee samples.

  7. 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.

  8. High sensitivity permeation measurement system for 'ultrabarrier' thin films

    SciTech Connect

    Zhang Xiaodong; Lewis, Jay S.; Wolter, Scott D.; Parker, Charles B.; Glass, Jeffrey T.

    2007-11-15

    The authors demonstrate a new technique for high sensitivity gas permeation measurements by integrating mass spectrometry with programed accumulation, detection, and evacuation of permeant. After passing through the film of interest, the gas permeant is captured and accumulated in an isolated ultrahigh vacuum (UHV) volume. The permeant is then allowed to enter an adjacent residual gas analyzer (RGA) and the resulting partial pressure increase is correlated with the steady state permeation rate. Calibrated results are given for helium and argon permeation through polymer films. The measured detection limits of the system are 1.8x10{sup -4} cm{sup 3}/m{sup 2} day for helium and 2.5x10{sup -4} cm{sup 3}/m{sup 2} day for argon. Both values are several orders of magnitude lower than what is available from commercial instruments or similar RGA-based instruments. Potential applications of this technique include measurement of oxygen and water vapor permeation with sensitivities required for assessment of ultrabarrier coatings.

  9. PlanetPol: A Very High Sensitivity Polarimeter

    NASA Astrophysics Data System (ADS)

    Hough, J. H.; Lucas, P. W.; Bailey, J. A.; Tamura, M.; Hirst, E.; Harrison, D.; Bartholomew-Biggs, M.

    2006-09-01

    We have built and used on several occasions an optical broadband stellar polarimeter, PlanetPol, which employs photoelastic modulators and avalanche photodiodes and achieves a photon-noise-limited sensitivity of at least 1 in 106 in fractional polarization. Observations of a number of polarized standards taken from the literature show that the accuracy of polarization measurements is ~1%. We have developed a method for accurately measuring the polarization of altitude-azimuth mounted telescopes by observing bright nearby stars at different parallactic angles, and we find that the on-axis polarization of the William Herschel Telescope is typically ~15 × 10-6, measured with an accuracy of a few parts in 107. The nearby stars (distance less than 32 pc) are found to have very low polarizations, typically a few ×10-6, indicating that very little interstellar polarization is produced close to the Sun and that their intrinsic polarization is also low. Although the polarimeter can be used for a wide range of astronomy, the very high sensitivity was set by the goal of detecting the polarization signature of unresolved extrasolar planets.

  10. Kinetics of Highly Sensitive Troponin T after Cardiac Surgery.

    PubMed

    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

  11. 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.

  12. 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.

  13. 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.

  14. Magnetic probe array with high sensitivity for fluctuating field.

    PubMed

    Kanamaru, Yuki; Gota, Hiroshi; Fujimoto, Kayoko; Ikeyama, Taeko; Asai, Tomohiko; Takahashi, Tsutomu; Nogi, Yasuyuki

    2007-03-01

    A magnetic probe array is constructed to measure precisely the spatial structure of a small fluctuating field included in a strong confinement field that varies with time. To exclude the effect of the confinement field, the magnetic probes consisting of figure-eight-wound coils are prepared. The spatial structure of the fluctuating field is obtained from a Fourier analysis of the probe signal. It is found that the probe array is more sensitive to the fluctuating field with a high mode number than that with a low mode number. An experimental demonstration of the present method is attempted using a field-reversed configuration plasma, where the fluctuating field with 0.1% of the confinement field is successfully detected.

  15. 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.

  16. 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.

  17. Evolution of a highly dilatant fault zone in the grabens of Canyonlands National Park, Utah/USA - integrating field work, 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.

    2015-03-01

    The grabens of the 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 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 model of the highly dilatant fault geometry in profile. Sinkholes observed in the field as well as in airborne imagery give insights in local massive dilatancy and show where water and sediments are transported underground. Based on correlations of paleosols observed in outcrops and GPR profiles, we argue that the grabens in Canyonlands National Park are either older than previously assumed, or that sedimentation rates were much higher in the Pleistocene.

  18. 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.

  19. 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.

  20. 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

  1. Introducing wet aerosols into the static high sensitivity ICP (SHIP).

    PubMed

    Scheffer, Andy; Engelhard, Carsten; Sperling, Michael; Buscher, Wolfgang

    2007-08-01

    A demountable design of the static high sensitivity ICP (SHIP) for optical emission spectrometry is presented, and its use as an excitation source with the introduction of wet aerosols was investigated. Aerosols were produced by standard pneumatic sample introduction systems, namely a cross flow nebulizer, Meinhard nebulizer and PFA low flow nebulizer, which have been applied in conjunction with a double pass and a cyclonic spray chamber. The analytical capabilities of these sample introduction systems in combination with the SHIP system were evaluated with respect to the achieved sensitivity. It was found that a nebulizer tailored for low argon flow rates (0.3-0.5 L min(-1)) is best suited for the low flow plasma (SHIP). An optimization of all gas flow rates of the SHIP system with the PFA low flow nebulizer was carried out in a two-dimensional way with the signal to background ratio (SBR) and the robustness as optimization target parameters. Optimum conditions for a torch model with 1-mm injector tube were 0.25 and 0.36 L min(-1) for the plasma gas and the nebulizer gas, respectively. A torch model with a 2-mm injector tube was optimized to 0.4 L min(-1) for the plasma gas and 0.44 L min(-1) for the nebulizer gas. In both cases the SHIP system saves approximately 95% of the argon consumed by conventional inductively coupled plasma systems. The limits of detection were found to be in the low microgram per litre range and below for many elements, which was quite comparable to those of the conventional setup. Furthermore, the short-term stability and the wash out behaviour of the SHIP were investigated. Direct comparison with the conventional setup indicated that no remarkable memory effects were caused by the closed design of the torch. The analysis of a NIST SRM 1643e (Trace Elements in Water) with the SHIP yielded recoveries of 97-103% for 13 elements, measured simultaneously.

  2. High-sensitivity (25-um pitch) microbolometer FPAs

    NASA Astrophysics Data System (ADS)

    Murphy, Daniel F.; Ray, Michael; Wyles, Richard; Asbrock, James F.; Lum, Nancy A.; Kennedy, Adam; Wyles, Jessica; Hewitt, C.; Graham, Glen E.; Horikiri, Tad; Anderson, John S.; Bradley, Daryl; Chin, Richard; Kostrzewa, Thomas

    2001-11-01

    RIO has achieved a significant technical breakthrough in uncooled FPAs by reducing the pixel size by a factor of two while maintaining state-of-the-art sensitivity. Raytheon has produced high-quality 320 by 240 micro bolometer FPAs with 25 micrometers pitch pixels. The 320 by 240 FPAs have a sensitivity that is comparable to micro bolometer FPAs with 50 micrometers pixels. The average NETD value for these FPAs is about 35 mK with an f/1 aperture and operating at 30 Hz frame rates. Good pixel operability and excellent image quality have been demonstrated. Pixel operability is greater than 99 percent on some FPAs, and uncorrected responsivity nonuniformity is less than 4 percent. The micro bolometer detectors also have a relatively fast thermal time constant of approximately 10 msec. This state-of-the-art performance has been achieved as a result of an advanced micromachining fabrication process. The process allows maximization of both the thermal isolation and the optical fill-factor. The reduction in pixel size offers several potential benefits for IR systems. For a given system resolution requirement, the 225 micrometers pixels allow a factor of two reduction in both the focal length and aperture size of the sensor optics. The pixel size reduction facilitates a significant FPA cost reduction since the number of die printed on a wafer can be increased. The pixel size reduction has enabled the development of a large-format 640 by 512 FPA array applicable to wide-field-of-view, long range surveillance and targeting missions, and a 160 by 128 array where applications for miniaturization and temperature invariance are required as well as low cost and low power.

  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 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

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. Conducting polymer nanofibers for high sensitivity detection of chemical analytes.

    NASA Astrophysics Data System (ADS)

    Kumar, Abhishek; Leshchiner, Ignaty; Nagarajan, Subhalakshmi; Nagarajan, Ramaswamy; Kumar, Jayant

    2008-03-01

    Possessing large surface area materials is vital for high sensitivity detection of analyte. We report a novel, inexpensive and simple technique to make high surface area sensing interfaces using electrospinning. Conducting polymers (CP) nanotubes were made by electrospinning a solution of a catalyst (ferric tosylate) along with poly (lactic acid), which is an environment friendly biodegradable polymer. Further vapor deposition polymerization of the monomer ethylenedioxy thiophene (EDOT) on the nanofiber surface yielded poly (EDOT) covered fibers. X-ray photo electron spectroscopy (XPS) study reveals the presence of PEDOT predominantly on the surface of nanofibers. Conducting nanotubes had been received by dissolving the polymer in the fiber core. By a similar technique we had covalently incorporated fluorescent dyes on the nanofiber surface. The materials obtained show promise as efficient sensing elements. UV-Vis characterization confirms the formation of PEDOT nanotubes and incorporation of chromophores on the fiber surface. The morphological characterization was carried out using scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

  12. Comparing standard Bonner spheres and high-sensitivity Bonner cylinders.

    PubMed

    Lee, Kuo-Wei; Yuan, Ming-Chen; Jiang, Shiang-Huei; Sheu, Rong-Jiun

    2014-10-01

    Standard Bonner spheres and proposed high-sensitivity Bonner cylinders were calibrated in a neutron calibration room, using a (252)Cf source. The Bonner sphere system consists of 11 polyethylene (PE) spheres of various diameters and 4 extended spheres that comprise embedded metal shells. Similar to the design of Bonner spheres, a set of Bonner cylinders was assembled using a large cylindrical (3)He tube as the central probe, which was wrapped using various thicknesses of PE. A layer of lead was employed inside one of the PE cylinders to increase the detection efficiency of high-energy neutrons. The central neutron probe used in the Bonner cylinders exhibited an efficiency of ∼17.9 times higher than that of the Bonner spheres. However, compared with the Bonner spheres, the Bonner cylinders are not fully symmetric in their geometry, exhibiting angular dependence in their responses to incoming neutrons. Using a series of calculations and measurements, this study presents a systematic comparison between Bonner spheres and cylinders in terms of their response functions, detection efficiencies, angular dependences and spectrum unfolding.

  13. 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

  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. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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

  1. 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.

  2. High sensitivity DNA detection based on regioselectively decorated electrocatalytic nanoparticles.

    PubMed

    Spain, Elaine; Brennan, Eoin; McArdle, Hazel; Keyes, Tia E; Forster, Robert J

    2012-08-01

    Self-assembled monolayers (SAMs) of dodecanethiol have been formed on gold electrodes to produce nanoscale defects. These defects define nucleation sites for the electrodeposition of mushroom shaped platinum nanoparticles (PtNPs). The top surfaces of these PtNPs have been selectively functionalized with single stranded probe DNA. These regioselectively modified particles were desorbed by applying a current jump to yield nanoparticles capable of biorecognition on the top curved side and efficient electrocatalysis on the nonfunctionalized lower surface. A second electrode was functionalized with single stranded capture DNA that has a sequence that is complementary to the pathogen, Staphylococcus aureus but leaves a section of the target available to bind the probe strand immobilized on the PtNPs. Following hybridization of the target and capture strands, the surface was exposed to the probe DNA labeled electrocatalytic PtNPs. Target binding was detected by monitoring the current associated with the reduction of hydrogen peroxide in a solution of 0.01 M H(2)SO(4). Calibration plots of the log[DNA] versus faradaic current were linear from 10 pM to 1 μM and picomolar concentrations could be detected without the need for amplification of the target, for example, using PCR or NASBA. As well as a wide dynamic range, this detection strategy has an excellent ability to discriminate DNA mismatches and a high analytical sensitivity. PMID:22747434

  3. Ultra-high sensitivity imaging of cancer using SERRS nanoparticles

    NASA Astrophysics Data System (ADS)

    Kircher, Moritz F.

    2016-05-01

    "Surface-enhanced Raman spectroscopy" (SERS) nanoparticles have gained much attention in recent years for in silico, in vitro and in vivo sensing applications. Our group has developed novel generations of biocompatible "surfaceenhanced resonance Raman spectroscopy" (SERRS) nanoparticles as novel molecular imaging agents. Via rigorous optimization of the different variables contributing to the Raman enhancement, we were able to design SERRS nanoparticles with so far unprecedented sensitivity of detection under in vivo imaging conditions (femto-attomolar range). This has resulted in our ability to visualize, with a single nanoparticle, many different cancer types (after intravenous injection) in mouse models. The cancer types we have tested so far include brain, breast, esophagus, stomach, pancreas, colon, sarcoma, and prostate cancer. All mouse models used are state-of-the-art and closely mimic the tumor biology in their human counterparts. In these animals, we were able to visualize not only the bulk tumors, but importantly also microscopic extensions and locoregional satellite metastases, thus delineating for the first time the true extent of tumor spread. Moreover, the particles enable the detection of premalignant lesions. Given their inert composition they are expected to have a high chance for clinical translation, where we envision them to have an impact in various scenarios ranging from early detection, image-guidance in open or minimally invasive surgical procedures, to noninvasive imaging in conjunction with spatially offset (SESORS) Raman detection devices.

  4. High resolution, position sensitive detector for energetic particle beams

    NASA Astrophysics Data System (ADS)

    Marsh, E. P.; Strathman, M. D.; Reed, D. A.; Morse, D. H.; Pontau, A. E.; Odom, R. W.

    1993-05-01

    The performance and design of an imaging position sensitive, particle beam detector will be presented. The detector is minimally invasive, operates over a wide dynamic range (> 10 10), and exhibits high spatial resolution. The secondary electrons produced when a particle beam passes through a thin foil are imaged using stigmatic ion optics onto a two-dimensional imaging detector. Due to the low scattering cross section of the 6 nm carbon foil the detector is a minimal perturbation on the primary beam. A prototype detector with an image resolution of approximately 5 μm for a field of view of 1 mm has been reported [R.W. Odom, M.D. Strathman, S.E. Buttrill, Jr., and S.M. Bauman, Nucl. Instr. and Meth. B44 (1990) 465]. A higher resolution detector for imaging small beams (< 50 μm) with an image resolution of better than 0.5 μm has since been developed and its design is presented.

  5. 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.

  6. Detection and enumeration of airborne biocontaminants.

    PubMed

    Stetzenbach, Linda D; Buttner, Mark P; Cruz, Patricia

    2004-06-01

    The sampling and analysis of airborne microorganisms has received attention in recent years owing to concerns with mold contamination in indoor environments and the threat of bioterrorism. Traditionally, the detection and enumeration of airborne microorganisms has been conducted using light microscopy and/or culture-based methods; however, these analyses are time-consuming, laborious, subjective and lack sensitivity and specificity. The use of molecular methods, such as quantitative polymerase chain reaction amplification, can enhance monitoring strategies by increasing sensitivity and specificity, while decreasing the time required for analysis.

  7. 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%.

  8. 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

  9. Webinar: Airborne Data Discovery and Analysis with Toolsets for Airborne Data (TAD)

    Atmospheric Science Data Center

    2016-10-18

    Webinar: Airborne Data Discovery and Analysis with Toolsets for Airborne Data (TAD) Wednesday, October 26, 2016 Join us on ... based on high-level parameter groups, mission, platform and flight data ranges are available. Registration is now open.  Access the full ...

  10. 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.

  11. 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).

  12. Proposed Ultra-High Sensitivity High-Frequency Gravitational Wave Detector

    NASA Astrophysics Data System (ADS)

    Baker, Robert M. L.; Stephenson, Gary V.; Li, Fangyu

    2008-01-01

    The paper discusses the proposed improvement of a High-Frequency Relic Gravitational Wave (HFRGW) detector designed by Li, Baker, Fang, Stephenson and Chen in order to greatly improve its sensitivity. The improved detector is inspired by the Laser Interferometer Gravitational Observatory or LIGO, but is sensitive to the high-frequency end of the gravitational-wave spectrum. As described in prior papers it utilizes the Gertsenshtein effect, which introduces the conversion of gravitational waves to electromagnetic (EM) waves in the presence of a static magnetic field. Such a conversion, if it leads to photons moving in a direction perpendicular to the plane of the EM waves and the magnetic field, will allow for ultra-high sensitivity HFRGW detection. The use of sensitive microwave, single photon detectors such as a circuit QED and/or the Rydberg Atom Cavity Detector, or off-the-shelf detectors, could lead to such detection. When the EM-detection photons are focused at the microwave detectors by fractal-membrane reflectors sensitivity is also improved. Noise sources external to the HFRGW detector will be eliminated by placing a tight mosaic of superconducting tiles (e.g., YBCO) and/or fractal membranes on the interior surface of the detector's cryogenic containment vessel in order to provide a perfect Faraday cage. Internal thermal noise will be eliminated by means of a microwave absorbing (or reflecting) interior enclosure shaped to conform to a high-intensity continuous microwave Gaussian beam (GB), will reduce any background photon flux (BPF) noise radiated normal to the GB's axis. Such BPF will be further attenuated by a series of microwave absorbing baffles forming tunnels to the sensitive microwave detectors on each side of the GB and at right angles to the static magnetic field. A HFGW detector of bandwidth of 1 KHz to 10 KHz or less in the GHz band has been selected. It is concluded that the utilization of the new ultra-high-sensitivity microwave detectors

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. High-resolution, high-sensitivity NMR of nanolitre anisotropic samples by coil spinning.

    PubMed

    Sakellariou, D; Le Goff, G; Jacquinot, J-F

    2007-06-01

    Nuclear magnetic resonance (NMR) can probe the local structure and dynamic properties of liquids and solids, making it one of the most powerful and versatile analytical methods available today. However, its intrinsically low sensitivity precludes NMR analysis of very small samples-as frequently used when studying isotopically labelled biological molecules or advanced materials, or as preferred when conducting high-throughput screening of biological samples or 'lab-on-a-chip' studies. The sensitivity of NMR has been improved by using static micro-coils, alternative detection schemes and pre-polarization approaches. But these strategies cannot be easily used in NMR experiments involving the fast sample spinning essential for obtaining well-resolved spectra from non-liquid samples. Here we demonstrate that inductive coupling allows wireless transmission of radio-frequency pulses and the reception of NMR signals under fast spinning of both detector coil and sample. This enables NMR measurements characterized by an optimal filling factor, very high radio-frequency field amplitudes and enhanced sensitivity that increases with decreasing sample volume. Signals obtained for nanolitre-sized samples of organic powders and biological tissue increase by almost one order of magnitude (or, equivalently, are acquired two orders of magnitude faster), compared to standard NMR measurements. Our approach also offers optimal sensitivity when studying samples that need to be confined inside multiple safety barriers, such as radioactive materials. In principle, the co-rotation of a micrometre-sized detector coil with the sample and the use of inductive coupling (techniques that are at the heart of our method) should enable highly sensitive NMR measurements on any mass-limited sample that requires fast mechanical rotation to obtain well-resolved spectra. The method is easy to implement on a commercial NMR set-up and exhibits improved performance with miniaturization, and we accordingly

  19. 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

  20. 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.

  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. 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.

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. 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)

  8. A high-sensitivity push-pull magnetometer

    NASA Astrophysics Data System (ADS)

    Breschi, E.; Grujić, Z. D.; Knowles, P.; Weis, A.

    2014-01-01

    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 .

  9. 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.

  10. 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.

  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. 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...

  13. Sensitive, high-strain, high-rate bodily motion sensors based on graphene-rubber composites.

    PubMed

    Boland, Conor S; Khan, Umar; Backes, Claudia; O'Neill, Arlene; McCauley, Joe; Duane, Shane; Shanker, Ravi; Liu, Yang; Jurewicz, Izabela; Dalton, Alan B; Coleman, Jonathan N

    2014-09-23

    Monitoring of human bodily motion requires wearable sensors that can detect position, velocity and acceleration. They should be cheap, lightweight, mechanically compliant and display reasonable sensitivity at high strains and strain rates. No reported material has simultaneously demonstrated all the above requirements. Here we describe a simple method to infuse liquid-exfoliated graphene into natural rubber to create conducting composites. These materials are excellent strain sensors displaying 10(4)-fold increases in resistance and working at strains exceeding 800%. The sensitivity is reasonably high, with gauge factors of up to 35 observed. More importantly, these sensors can effectively track dynamic strain, working well at vibration frequencies of at least 160 Hz. At 60 Hz, we could monitor strains of at least 6% at strain rates exceeding 6000%/s. We have used these composites as bodily motion sensors, effectively monitoring joint and muscle motion as well and breathing and pulse.

  14. High-speed high-sensitivity infrared spectroscopy using mid-infrared swept lasers (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Childs, David T. D.; Groom, Kristian M.; Hogg, Richard A.; Revin, Dmitry G.; Cockburn, John W.; Rehman, Ihtesham U.; Matcher, Stephen J.

    2016-03-01

    Infrared spectroscopy is a highly attractive read-out technology for compositional analysis of biomedical specimens because of its unique combination of high molecular sensitivity without the need for exogenous labels. Traditional techniques such as FTIR and Raman have suffered from comparatively low speed and sensitivity however recent innovations are challenging this situation. Direct mid-IR spectroscopy is being speeded up by innovations such as MEMS-based FTIR instruments with very high mirror speeds and supercontinuum sources producing very high sample irradiation levels. Here we explore another possible method - external cavity quantum cascade lasers (EC-QCL's) with high cavity tuning speeds (mid-IR swept lasers). Swept lasers have been heavily developed in the near-infrared where they are used for non-destructive low-coherence imaging (OCT). We adapt these concepts in two ways. Firstly by combining mid-IR quantum cascade gain chips with external cavity designs adapted from OCT we achieve spectral acquisition rates approaching 1 kHz and demonstrate potential to reach 100 kHz. Secondly we show that mid-IR swept lasers share a fundamental sensitivity advantage with near-IR OCT swept lasers. This makes them potentially able to achieve the same spectral SNR as an FTIR instrument in a time x N shorter (N being the number of spectral points) under otherwise matched conditions. This effect is demonstrated using measurements of a PDMS sample. The combination of potentially very high spectral acquisition rates, fundamental SNR advantage and the use of low-cost detector systems could make mid-IR swept lasers a powerful technology for high-throughput biomedical spectroscopy.

  15. Pajarito Monitor: a high-sensitivity monitoring system for highly enriched uranium

    SciTech Connect

    Fehlau, P.E.; Coop, K.; Garcia, C. Jr.; Martinez, J.

    1984-01-01

    The Pajarito Monitor for Special Nuclear Material is a high-sensitivity gamma-ray monitoring system for detecting small quantities of highly enriched uranium transported by pedestrians or motor vehicles. The monitor consists of two components: a walk-through personnel monitor and a vehicle monitor. The personnel monitor has a plastic-scintillator detector portal, a microwave occupancy monitor, and a microprocessor control unit that measures the radiation intensity during background and monitoring periods to detect transient diversion signals. The vehicle monitor examines stationary motor vehicles while the vehicle's occupants pass through the personnel portal to exchange their badges. The vehicle monitor has four groups of large plastic scintillators that scan the vehicle from above and below. Its microprocessor control unit measures separate radiation intensities in each detector group. Vehicle occupancy is sensed by a highway traffic detection system. Each monitor's controller is responsible for detecting diversion as well as serving as a calibration and trouble-shooting aid. Diversion signals are detected by a sequential probability ratio hypothesis test that minimizes the monitoring time in the vehicle monitor and adapts itself well to variations in individual passage speed in the personnel monitor. Designed to be highly sensitive to diverted enriched uranium, the monitoring system also exhibits exceptional sensitivity for plutonium. 6 references, 9 figures, 2 tables.

  16. 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

  17. Airborne Transmission of Influenza A/H5N1 Virus Between Ferrets

    PubMed Central

    Herfst, Sander; Schrauwen, Eefje J. A.; Linster, Martin; Chutinimitkul, Salin; de Wit, Emmie; Munster, Vincent J.; Sorrell, Erin M.; Bestebroer, Theo M.; Burke, David F.; Smith, Derek J.; Rimmelzwaan, Guus F.; Osterhaus, Albert D. M. E.; Fouchier, Ron A. M.

    2016-01-01

    Highly pathogenic avian influenza A/H5N1 virus can cause morbidity and mortality in humans but thus far has not acquired the ability to be transmitted by aerosol or respiratory droplet (“airborne transmission”) between humans. To address the concern that the virus could acquire this ability under natural conditions, we genetically modified A/H5N1 virus by site-directed mutagenesis and subsequent serial passage in ferrets. The genetically modified A/H5N1 virus acquired mutations during passage in ferrets, ultimately becoming airborne transmissible in ferrets. None of the recipient ferrets died after airborne infection with the mutant A/H5N1 viruses. Four amino acid substitutions in the host receptor-binding protein hemagglutinin, and one in the polymerase complex protein basic polymerase 2, were consistently present in airborne-transmitted viruses. The transmissible viruses were sensitive to the antiviral drug oseltamivir and reacted well with antisera raised against H5 influenza vaccine strains. Thus, avian A/H5N1 influenza viruses can acquire the capacity for airborne transmission between mammals without recombination in an intermediate host and therefore constitute a risk for human pandemic influenza. PMID:22723413

  18. 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.

  19. 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

  20. Extremely high frequency sensitivity in a 'simple' ear.

    PubMed

    Moir, Hannah M; Jackson, Joseph C; Windmill, James F C

    2013-08-23

    An evolutionary war is being played out between the bat, which uses ultrasonic calls to locate insect prey, and the moth, which uses microscale ears to listen for the approaching bat. While the highest known frequency of bat echolocation calls is 212 kHz, the upper limit of moth hearing is considered much lower. Here, we show that the greater wax moth, Galleria mellonella, is capable of hearing ultrasonic frequencies approaching 300 kHz; the highest frequency sensitivity of any animal. With auditory frequency sensitivity that is unprecedented in the animal kingdom, the greater wax moth is ready and armed for any echolocation call adaptations made by the bat in the on-going bat-moth evolutionary war.

  1. Highly sensitive straightness measurement system using a ball-lens

    NASA Astrophysics Data System (ADS)

    Lee, Minho; Yang, Hyun-Ik; Cho, Nahm-Gyoo

    2016-01-01

    In this paper, a new and simple optical technique to accurately measure the straightness errors of a linear stage is proposed. To improve the performance, including the measurement sensitivity and resolution of the measurement system, and to simultaneously measure two-dimensional straightness errors (2D straightness errors), an optical system was designed using a laser, a retro-reflector, a ball-lens, and a two-dimensional position sensitive detector (2D PSD). The characteristics of the measurement system were analytically and experimentally investigated. A prototype measurement system was manufactured based on the investigated results, and the performances of this system have been tested. The measuring performance of the system was easily improved by about 12 times using the proposed technique and it can be further improved. It is shown that the proposed technique can easily and effectively improve the performance of a conventional straightness measurement system based on the geometric optical method using a PSD.

  2. 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.

  3. Low frequency, high sensitive tunable mechanical monolithic horizontal sensors

    NASA Astrophysics Data System (ADS)

    Acernese, Fausto; De Rosa, Rosario; Giordano, Gerardo; Romano, Rocco; Vilasi, Silvia; Barone, Fabrizio

    2011-04-01

    This paper describes an optimized version of the mechanical version of the monolithic tunable folded pendulum, developed at the University of Salerno, configurable both as seismometer and, in a force-feedback configuration, as accelerometer. Typical application of the sensors are in the field of geophysics, including the study of seismic and newtonian noise for characterization of suitable sites for underground interferometer for gravitational waves detection. The sensor, shaped with precision machining and electric-discharge-machining, like the previous version, is a very compact instrument, very sensitive in the low-frequency seismic noise band, with a very good immunity to environmental noises. Important characteristics are the tunability of the resonance frequency and the integrated laser optical readout, consisting of an optical lever and an interferometer. The theoretical sensitivity curves, largely improved due to a new design of the pendulum arms and of the electronics, are in a very good agreement with the measurements. The very large measurement band (10-6 +/- 10Hz) is couple to a very good sensitivity (10-12 m/√Hz in the band 0.1 +/- 10Hz), as seismometer. Prototypes of monolithic seismometers are already operational in selected sites around the world both to acquire seismic data for scientific analysis of seismic noise and to collect all the useful information to understand their performances in the very low frequency band (f < 1mHz). The results of the monolithic sensor as accelerometer (force feed-back configuration) are also presented and discussed. Particular relevance has their sensitivity that is better than 10-11 m/s2/√Hz in the band 0.1 +/- 10Hz. Finally, hypotheses are made on further developments and improvements of monolithic sensors.

  4. The strain-rate sensitivity of high-strength high-toughness steels.

    SciTech Connect

    Dilmore, M.F.; Crenshaw, Thomas B.; Boyce, Brad Lee

    2006-01-01

    The present study examines the strain-rate sensitivity of four high strength, high-toughness alloys at strain rates ranging from 0.0002 s-1 to 200 s-1: Aermet 100, a modified 4340, modified HP9-4-20, and a recently developed Eglin AFB steel alloy, ES-1c. A refined dynamic servohydraulic method was used to perform tensile tests over this entire range. Each of these alloys exhibit only modest strain-rate sensitivity. Specifically, the strain-rate sensitivity exponent m, is found to be in the range of 0.004-0.007 depending on the alloy. This corresponds to a {approx}10% increase in the yield strength over the 7-orders of magnitude change in strain-rate. Interestingly, while three of the alloys showed a concominant {approx}3-10% drop in their ductility with increasing strain-rate, the ES1-c alloy actually exhibited a 25% increase in ductility with increasing strain-rate. Fractography suggests the possibility that at higher strain-rates ES-1c evolves towards a more ductile dimple fracture mode associated with microvoid coalescence.

  5. 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.

  6. 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.

  7. 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…

  8. 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.

  9. High-performance and high-sensitivity applications of graphene transistors with self-assembled monolayers.

    PubMed

    Yeh, Chao-Hui; Kumar, Vinod; Moyano, David Ricardo; Wen, Shao-Hsuan; Parashar, Vyom; Hsiao, She-Hsin; Srivastava, Anchal; Saxena, Preeti S; Huang, Kun-Ping; Chang, Chien-Chung; Chiu, Po-Wen

    2016-03-15

    Charge impurities and polar molecules on the surface of dielectric substrates has long been a critical obstacle to using graphene for its niche applications that involve graphene's high mobility and high sensitivity nature. Self-assembled monolayers (SAMs) have been found to effectively reduce the impact of long-range scatterings induced by the external charges. Yet, demonstrations of scalable device applications using the SAMs technique remains missing due to the difficulties in the device fabrication arising from the strong surface tension of the modified dielectric environment. Here, we use patterned SAM arrays to build graphene electronic devices with transport channels confined on the modified areas. For high-mobility applications, both rigid and flexible radio-frequency graphene field-effect transistors (G-FETs) were demonstrated, with extrinsic cutoff frequency and maximum oscillation frequency enhanced by a factor of ~2 on SiO2/Si substrates. For high sensitivity applications, G-FETs were functionalized by monoclonal antibodies specific to cancer biomarker chondroitin sulfate proteoglycan 4, enabling its detection at a concentration of 0.01 fM, five orders of magnitude lower than that detectable by a conventional colorimetric assay. These devices can be very useful in the early diagnosis and monitoring of a malignant disease. PMID:26547427

  10. Validation of high-resolution WRF-ARW model runs against airborne measurements over complex terrain in central Italy

    NASA Astrophysics Data System (ADS)

    Carotenuto, Federico; Gioli, Beniamino; Toscano, Piero; Gualtieri, Giovanni; Miglietta, Franco; Wohlfahrt, Georg

    2015-04-01

    An intensive aerial campaign was flown in the context of the CARBIUS project (Maselli et al., 2010) between July 2004 and December 2005. The flights covered, over more than 240 Km, a target area in central Italy (between the regions of Lazio and Tuscany) characterized by various land uses and topography, ranging from coastal zones to mountainous landscapes (Colline Metallifere, Tuscany). The aerial vector (Sky Arrow 650 ERA) was equipped for high frequency (50 Hz) measurements of the three components of mean wind and turbulence, as well as air temperature, CO2 and H2O concentrations. While the aim of the CARBIUS campaign was focused on GHG fluxes, the dataset is used in the present work as a benchmark to assess the capability of mesoscale models to correctly simulate transport fields. A first assessment has been done by comparing the dataset to a coupled WRF-NMM-CALMET system (Gioli et al., 2014), but the aim of the present work is to expand on those foundations by comparing the data to higher resolution WRF-ARW simulations. WRF-ARW outputs are, in fact, frequently used as inputs to multiple dispersion models and any misrepresentation of the "real" situation is therefore propagated through the modelling chain. Our aim is to assess these potential errors keeping into account different topographic situations and seasons thanks to the existent aerial dataset. Moreover the sensitivity of the WRF-ARW model to different initial and boundary conditions (ECMWF vs. CFSR) is explored, since also the initial forcing may influence the representation of the transport field. Results show that the model is generally capable of reproducing the main features of the mean wind field independently from the choice of the initial forcing. Terrain features still show an impact on the model outputs (especially on wind directions), moreover the performance of the model is also influenced by seasonal effects. Gioli B., Gualtieri G., Busillo C., Calastrini F., Gozzini B., Miglietta F. (2014

  11. 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.

  12. Advanced Cd(II) complexes as high efficiency co-sensitizers for enhanced dye-sensitized solar cell performance.

    PubMed

    Gao, Song; Fan, Rui Qing; Wang, Xin Ming; Qiang, Liang Sheng; Wei, Li Guo; Wang, Ping; Yang, Yu Lin; Wang, Yu Lei

    2015-11-01

    This work reports on two new complexes with the general formula [Cd3(IBA)3(Cl)2(HCOO)(H2O)]n (1) and {[Cd1.5(IBA)3(H2O)6]·3.5H2O}n (2), which can be synthesized by the reaction of Cd(II) with rigid linear ligand 4-HIBA containing imidazolyl and carboxylate functional groups [4-HIBA = 4-(1H-imidazol-1-yl)benzoic acid]. Single-crystal X-ray diffraction analyses indicate that complex 1 is a 2D "wave-like" layer structure constructed from trinuclear units and complex 2 is just a mononuclear structure. Surprisingly, both complexes 1 and 2 appear as a 3D supramolecular network via intermolecular hydrogen bonding interactions. What's more, due to their strong UV-visible absorption, 1 and 2 can be employed as co-sensitizers in combination with N719 to enhance dye-sensitized solar cell (DSSC) performance. Both of them could overcome the deficiency of the ruthenium complex N719 absorption in the region of ultraviolet and blue-violet, and the charge collection efficiency is also improved when 1 and 2 are used as co-sensitizers, which are all in favor of enhancing the performance. The DSSC devices using co-sensitizers of 1/N719 and 2/N719 show an overall conversion efficiency of 8.27% and 7.73% with a short circuit current density of 17.48 mA cm(-2) and 17.39 mA cm(-2), and an open circuit voltage of 0.75 V and 0.74 V, respectively. The overall conversion efficiency is 27.23% and 18.92% higher than that of a device solely sensitized by N719 (6.50%). Consequently, the prepared complexes are high efficiency co-sensitizers for enhancing the performance of N719 sensitized solar cells. PMID:26419745

  13. Sensitivity analysis for high accuracy proximity effect correction

    NASA Astrophysics Data System (ADS)

    Thrun, Xaver; Browning, Clyde; Choi, Kang-Hoon; Figueiro, Thiago; Hohle, Christoph; Saib, Mohamed; Schiavone, Patrick; Bartha, Johann W.

    2015-10-01

    A sensitivity analysis (SA) algorithm was developed and tested to comprehend the influences of different test pattern sets on the calibration of a point spread function (PSF) model with complementary approaches. Variance-based SA is the method of choice. It allows attributing the variance of the output of a model to the sum of variance of each input of the model and their correlated factors.1 The objective of this development is increasing the accuracy of the resolved PSF model in the complementary technique through the optimization of test pattern sets. Inscale® from Aselta Nanographics is used to prepare the various pattern sets and to check the consequences of development. Fraunhofer IPMS-CNT exposed the prepared data and observed those to visualize the link of sensitivities between the PSF parameters and the test pattern. First, the SA can assess the influence of test pattern sets for the determination of PSF parameters, such as which PSF parameter is affected on the employments of certain pattern. Secondly, throughout the evaluation, the SA enhances the precision of PSF through the optimization of test patterns. Finally, the developed algorithm is able to appraise what ranges of proximity effect correction is crucial on which portion of a real application pattern in the electron beam exposure.

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. Highly sensitive methods for electroanalytical chemistry based on nanotubule membranes.

    PubMed

    Kobayashi, Y; Martin, C R

    1999-09-01

    Two new methods of electroanalysis are described. These methods are based on membranes containing monodisperse Au nanotubules with inside diameters approaching molecular dimensions. In one method, the analyte species is detected by measuring the change in trans-membrane current when the analyte is added to the nanotubule-based cell. The second method entails the use of a concentration cell based on the nanotubule membrane. In this case, the change in membrane potential is used to detect the analyte. Detection limits as low as 10(-11) M have been achieved. Hence, these methods compete with even the most sensitive of modern analytical methodologies. In addition, excellent molecular-sized-based selectivity is observed.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  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. 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.

  6. 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

  7. Mars Airborne Prospecting Spectrometer

    NASA Astrophysics Data System (ADS)

    Steinkraus, J. M.; Wright, M. W.; Rheingans, B. E.; Steinkraus, D. E.; George, W. P.; Aljabri, A.; Hall, J. L.; Scott, D. C.

    2012-06-01

    One novel approach towards addressing the need for innovative instrumentation and investigation approaches is the integration of a suite of four spectrometer systems to form the Mars Airborne Prospecting Spectrometers (MAPS) for prospecting on Mars.

  8. 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

  9. Airborne measurements in the longwave infrared using an imaging hyperspectral sensor

    NASA Astrophysics Data System (ADS)

    Allard, Jean-Pierre; Chamberland, Martin; Farley, Vincent; Marcotte, Frédérick; Rolland, Matthias; Vallières, Alexandre; Villemaire, André

    2008-07-01

    Emerging applications in Defense and Security require sensors with state-of-the-art sensitivity and capabilities. Among these sensors, the imaging spectrometer is an instrument yielding a large amount of rich information about the measured scene. Standoff detection, identification and quantification of chemicals in the gaseous state is one important application. Analysis of the surface emissivity as a means to classify ground properties and usage is another one. Imaging spectrometers have unmatched capabilities to meet the requirements of these applications. Telops has developed the FIRST, a LWIR hyperspectral imager. The FIRST is based on the Fourier Transform technology yielding high spectral resolution and enabling high accuracy radiometric calibration. The FIRST, a man portable sensor, provides datacubes of up to 320×256 pixels at 0.35mrad spatial resolution over the 8-12 μm spectral range at spectral resolutions of up to 0.25cm-1. The FIRST has been used in several field campaigns, including the demonstration of standoff chemical agent detection [http://dx.doi.org/10.1117/12.788027.1]. More recently, an airborne system integrating the FIRST has been developed to provide airborne hyperspectral measurement capabilities. The airborne system and its capabilities are presented in this paper. The FIRST sensor modularity enables operation in various configurations such as tripod-mounted and airborne. In the airborne configuration, the FIRST can be operated in push-broom mode, or in staring mode with image motion compensation. This paper focuses on the airborne operation of the FIRST sensor.

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. Validation of satellite overland retrievals of AOD at northern high latitudes with coincident measurements from airborne sunphotometer, lidar, and in situ sensors during ARCTAS

    NASA Astrophysics Data System (ADS)

    Livingston, J. M.; Shinozuka, Y.; Redemann, J.; Russell, P. B.; Ramachandran, S.; Johnson, R. R.; Clarke, A. D.; Howell, S. G.; McNaughton, C.; Freitag, S.; Kapustin, V. N.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. W.; Torres, O.; Veefkind, P.; Remer, L. A.; Mattoo, S.; Levy, R. C.; Chu, A. D.; Kahn, R. A.; Davis, M. R.

    2009-12-01

    The 2008 Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) field campaign presented a unique opportunity for validation of satellite retrievals of aerosol optical depth (AOD) over a variety of surfaces at northern high latitudes. In particular, the 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) was operated together with a variety of in-situ and other remote sensors aboard the NASA P-3B research aircraft during both the spring and summer phases of ARCTAS. Among the in-situ sensors were a nephelometer and particle soot absorption photometer (PSAP) operated by University of Hawaii Group for Environmental Aerosol Research (HIGEAR). P-3B science missions included several coincident underflights of the Terra and A-Train satellites during a variety of aerosol loading conditions, including Arctic haze and smoke plumes from boreal forest fires. In this presentation, we will compare AATS-14 AOD spectra, adjusted for the contribution from the layer below the aircraft using the HiGEAR scattering and absorption measurements, with full column AOD retrievals from coincident measurements by satellite sensors such as MISR, MODIS, OMI, and POLDER. We also intend to show comparisons of aerosol extinction derived from AATS-14 measurements during P-3B vertical profiles with coincident measurements from CALIOP aboard the CALIPSO satellite and from the high spectral resolution lidar (HSRL) flown aboard the NASA B-200 aircraft.

  16. 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.

  17. 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

  18. Highly sensitive homogenous chemiluminescence immunoassay using gold nanoparticles as label

    NASA Astrophysics Data System (ADS)

    Luo, Jing; Cui, Xiang; Liu, Wei; Li, Baoxin

    2014-10-01

    Homogeneous immunoassay is becoming more and more attractive for modern medical diagnosis because it is superior to heterogeneous immunoassay in sample and reagent consumption, analysis time, portability and disposability. Herein, a universal platform for homogeneous immunoassay, using human immunoglobulin G (IgG) as a model analyte, has been developed. This assay relies upon the catalytic activity of gold nanoparticles (AuNPs) on luminol-AgNO3 chemiluminescence (CL) reaction. The immunoreaction of antigen and antibody can induce the aggregation of antibody-functionalized AuNPs, and after aggregation the catalytic activity of AuNPs on luminol-AgNO3 CL reaction is greatly enhanced. Without any separation steps, a CL signal is generated upon addition of a trigger solution, and the CL intensity is directly correlated to the quantity of IgG. The detection limit of IgG was estimated to be as low as 3 pg/mL, and the sensitivity was better than that of the reported AuNPs-based CL immunoassay for IgG.

  19. Highly sensitive self-complementary DNA nanoswitches triggered by polyelectrolytes.

    PubMed

    Wu, Jincai; Yu, Feng; Zhang, Zheng; Chen, Yong; Du, Jie; Maruyama, Atsushi

    2016-01-01

    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.

  20. High-sensitivity observations of solar flare decimeter radiation

    NASA Astrophysics Data System (ADS)

    Benz, A. O.; Messmer, P.; Monstein, C.

    2001-01-01

    A new acousto-optic radio spectrometer has observed the 1-2 GHz radio emission of solar flares with unprecedented sensitivity. The number of detected decimeter type III bursts is greatly enhanced compared to observations by conventional spectrometers observing only one frequency at the time. The observations indicate a large number of electron beams propagating in dense plasmas. For the first time, we report weak, reversed drifting type III bursts at frequencies above simultaneous narrowband decimeter spikes. The type III bursts are reliable signatures of electron beams propagating downward in the corona, apparently away from the source of the spikes. The observations contradict the most popular spike model that places the spike sources at the footpoints of loops. Conspicuous also was an apparent bidirectional type U burst forming a fish-like pattern. It occurs simultaneously with an intense U-burst at 600-370 MHz observed in Tremsdorf. We suggest that it intermodulated with strong terrestrial interference(cellular phones) causing a spurious symmetric pattern in the spectrogram at 1.4 GHz. Symmetric features in the 1-2 GHz range, some already reported in the literature, therefore must be considered with utmost caution.

  1. 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

  2. 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.

  3. 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.

  4. Highly sensitive amyloid detection enabled by thioflavin T dimers.

    PubMed

    Qin, Luoheng; Vastl, Julian; Gao, Jianmin

    2010-10-01

    Fluorescent molecules that specifically target amyloid structures are highly desirable for amyloid research. Herein, we show a dimeric design of thioflavin T improves its binding affinity to Abeta amyloid by up to 70 fold, while not sacrificing the specificity and the "light-up" feature upon amyloid binding.

  5. 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...

  6. 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.

  7. 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...

  8. 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.

  9. 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

  10. 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

  11. PCF Based Sensor with High Sensitivity, High Birefringence and Low Confinement Losses for Liquid Analyte Sensing Applications.

    PubMed

    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. Direct analysis of airborne mite allergen (Der f1) in the residential atmosphere by chemifluorescent immunoassay using bioaerosol sampler.

    PubMed

    Miyajima, Kumiko; Suzuki, Yurika; Miki, Daisuke; Arai, Moeka; Arakawa, Takahiro; Shimomura, Hiroji; Shiba, Kiyoko; Mitsubayashi, Kohji

    2014-06-01

    Dermatophagoides farinae allergen (Der f1) is one of the most important indoor allergens associated with allergic diseases in humans. Mite allergen Der f1 is usually associated with particles of high molecular weight; thus, Der f1 is generally present in settled dust. However, a small quantity of Der f1 can be aerosolized and become an airborne component. Until now, a reliable method of detecting airborne Der f1 has not been developed. The aim of this study was to develop a fiber-optic chemifluorescent immunoassay for the detection of airborne Der f1. In this method, the Der f1 concentration measured on the basis of the intensity of fluorescence amplified by an enzymatic reaction between the labeled enzyme by a detection antibody and a fluorescent substrate. The measured Der f1 concentration was in the range from 0.49 to 250 ng/ml and a similar range was found by enzyme-linked immunosorbent assay (ELISA). This method was proved to be highly sensitive to Der f1 compared with other airborne allergens. For the implementation of airborne allergen measurement in a residential environment, a bioaerosol sampler was constructed. The airborne allergen generated by a nebulizer was conveyed to a newly sampler we developed for collecting airborne Der f1. The sampler was composed of polymethyl methacrylate (PMMA) cells for gas/liquid phases and some porous membranes which were sandwiched in between the two phases. Der f1 in air was collected by the sampler and measured using the fiber-optic immunoassay system. The concentration of Der f1 in aerosolized standards was in the range from 0.125 to 2.0 mg/m(3) and the collection rate of the device was approximately 0.2%.

  14. 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.

  15. 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

  16. 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

  17. High Explosive Deonation Threshold Sensitivity Due to Multiple Fragment Impacts

    SciTech Connect

    Georgevich, V; Pincosy, P; Chase, J

    2004-01-07

    Fragments, bullets or projectiles can initiate a detonation in a high explosive (HE). For this to happen certain critical conditions need to be exceeded. For a given explosive, these critical conditions are the projectile velocity, the projectile size and shape, and the projectile material properties. A lot of work has been done in the area of metal shaped charge jets and individual fragments impacting the HE. One major gap in understanding initiation phenomena is the effect of multiple fragment impact. This study shows that multiple fragments can lower the fragment size and the kinetic energy thresholds.

  18. 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.

  19. A Highly Sensitive, High-Throughput Assay for the Detection of Turner Syndrome

    PubMed Central

    Hager, Karl; Hosono, Seiyu; Wise, Anastasia; Li, Peining; Rinder, Henry M.; Gruen, Jeffrey R.

    2011-01-01

    Objective: Turner syndrome (TS) occurs when an X-chromosome is completely or partially deleted or when X-chromosomal mosaicism is present. Girls with TS benefit from early diagnosis and treatment with GH; however, many girls with TS are not detected until after 10 yr of age, resulting in delayed evaluation and treatment. Methods: We developed a high-throughput test for TS, based on a quantitative method of genotyping to detect X-chromosome abnormalities. This test uses pyrosequencing to quantitate relative allele strength (RAS) from single-nucleotide polymorphisms using 18 informative single-nucleotide polymorphisms markers that span the X-chromosome and one marker for the detection of Y-chromosome material. Results: Cutoff ranges for heterozygous, homozygous, or out-of-range RAS values were established from a cohort of 496 males and females. Positive TS scoring criteria were defined as the presence of homozygosity for all 18 markers or the presence of at least one out-of-range RAS value. To determine the validity of this rapid test for TS detection, we undertook a large-scale study using DNA from 132 females without TS and 74 females with TS for whom karyotypes were available. TS was identified with 96.0% sensitivity and 97.0% specificity in this cohort. We also tested buccal swab DNA from a group of 19 females without TS and 69 females with TS. In this group, TS was identified with 97.1% sensitivity and 84.2% specificity. Conclusions: These results demonstrate the validity of a high-throughput, pyrosequencing based test for the accurate detection of TS, providing a potential alternative to karyotype testing. PMID:21177792

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  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. Highly Sensitive Nanoparticle-based Multifunctional Biosensor for Antigen Detection

    NASA Astrophysics Data System (ADS)

    Siavoshi, Salome

    Precise and selective positioning of nanoparticles gives rise to many applications where assembly of nano building blocks with different biological or chemical functionalization is necessary. One remarkable application is the simultaneous early detection of multiple biomarkers in the field of miniaturized multiplex biosensors. To enable multiplex detection of antigens, nanoparticles with various antibody coatings can be selectively assembled in trenches on different regions on a biochip so that they bind selectively to the specific antigen of interest. The presented work utilizes electric field assisted assembly techniques to assemble nanoparticles with various surface functionalization and coatings. Nanoparticles are assembled into pre-fabricated via and trench patterns generated on a PMMA coated gold surface, using electron-beam lithography. Two techniques have been developed for selective assembly of nanoparticles: sequential size-selective directed assembly and sequential site-selective assembly. Both selective assembly techniques provide fast and reproducible assembly over large areas while achieving high yield. The sequential size-selective assembly is a template-assisted technique where the selectivity is achieved by controlling the size of the nanopatterns and the size of the nanoparticles. The possibility of particle detachment and the factors affecting the sorting efficiency for this technique is studied. We show that a complete sorting can be achieved when the size of the vias is close to the diameter of the nanoparticles and the size distribution of the chosen nanoparticles do not overlap. In the site-selective assembly, the selectivity is achieved by having electrically isolated sites (regions) on the same chip. Electrophoresis is performed for each region in a step by step process. Selective assembly results, for up to four nanoparticles with various coating/functionalization are presented using the site-selective assembly technique. We use the

  6. (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.

  7. 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.

  8. 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.

  9. 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.

  10. Reduced graphene oxide electrically contacted graphene sensor for highly sensitive nitric oxide detection.

    PubMed

    Li, Weiwei; Geng, Xiumei; Guo, Yufen; Rong, Jizan; Gong, Youpin; Wu, Liqiong; Zhang, Xuemin; Li, Peng; Xu, Jianbao; Cheng, Guosheng; Sun, Mengtao; Liu, Liwei

    2011-09-27

    We develop graphene-based devices fabricated by alternating current dielectrophoresis (ac-DEP) for highly sensitive nitric oxide (NO) gas detection. The novel device comprises the sensitive channels of palladium-decorated reduced graphene oxide (Pd-RGO) and the electrodes covered with chemical vapor deposition (CVD)-grown graphene. The highly sensitive, recoverable, and reliable detection of NO gas ranging from 2 to 420 ppb with response time of several hundred seconds has been achieved at room temperature. The facile and scalable route for high performance suggests a promising application of graphene devices toward the human exhaled NO and environmental pollutant detections. PMID:21834585

  11. Distinct susceptibility to inoculated melanoma and sensitivity to cancer pain in mouse lines with high and low sensitivity to stress.

    PubMed

    Sacharczuk, Mariusz; Ragan, Agnieszka R; Szymanska, Hanna; Lesniak, Anna; Sadowski, Bogdan; Lipkowski, Andrzej W

    2012-01-01

    Approximately 30 years ago, we developed 2 mouse lines with enhanced and decreased opioid system activity using bidirectional selection for high (high analgesia [HA] line) and low (low analgesia [LA] line) swim stress-induced analgesia. These mouse lines differ substantially in pain sensitivity, measured as hind paw withdrawal latency in a hot plate test. Moreover, compared with the LA mice, the HA mice exhibited reduced energy expenditure under stress and different depression-like behavior as well as higher sensitivity to mutagens and the high frequency of spontaneous and carcinogen-induced tumors. In the current study, we observed distinct differences in the growth rate of orthotopically implanted melanoma and the onset of cancer pain. Whereas the HA line was prone to tumors and carcinogenesis was rapid in all specimens, the LA mice either did not develop tumors (70%) or developed tumors that often regressed spontaneously (30%). Animals from both lines developed robust thermal hypersensitivity in the tumor-bearing paw compared with animals that were injected with saline. However, we found that hyperalgesia in tumor-bearing mice persists for a much shorter time in the HA than in LA mice. Naltrexone, given subcutaneously, restored hyperalgesia in the HA mice, whereas it was ineffective in the LA mice. The results suggest that activity of the opioid system may influence carcinogenesis and the intensity of cancer pain and indicates that HA and LA mice are good models for such studies. PMID:23216641

  12. 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

  13. 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…

  14. Airborne data acquisition techniques

    SciTech Connect

    Arro, A.A.

    1980-01-01

    The introduction of standards on acceptable procedures for assessing building heat loss has created a dilemma for the contractor performing airborne thermographic surveys. These standards impose specifications on instrumentation, data acquisition, recording, interpretation, and presentation. Under the standard, the contractor has both the obligation of compliance and the requirement of offering his services at a reasonable price. This paper discusses the various aspects of data acquisition for airborne thermographic surveys and various techniques to reduce the costs of this operation. These techniques include the calculation of flight parameters for economical data acquisition, the selection and use of maps for mission planning, and the use of meteorological forecasts for flight scheduling and the actual execution of the mission. The proper consideration of these factors will result in a cost effective data acquisition and will place the contractor in a very competitive position in offering airborne thermographic survey services.

  15. 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.

  16. VTEM airborne EM, aeromagnetic and gamma-ray spectrometric data over the Cerro Quema high sulphidation epithermal gold deposits, Panama

    NASA Astrophysics Data System (ADS)

    Kwan, Karl; Prikhodko, Alexander; Legault, Jean M. Plastow, Geoffrey C.; Kapetas, John; Druecker, Michael

    2016-03-01

    In March 2012, a helicopter-borne versatile time-domain electromagnetic (VTEM), magnetic and radiometric survey was flown over the Cerro Quema high sulphidation (HS) epithermal gold deposits and the surrounding area. The Cerro Quema deposits are located in the Azuero Peninsula, Panama, approximately 8 km east of Güerita. The gold mineralisation is associated with clay-pyrite alterations topped by an acid-leached resistive cap, and the principal ores are pyrite-rich sulphides located within mineralised vuggy silica rocks. The geophysical data over the Cerro Quema deposits have been analysed. The electromagnetic (EM) responses over the deposits are characterised by resistivity highs and chargeability lows, surrounded by resistivity lows and chargeability highs. Radiometric Th/K ratio highs and magnetic susceptibility lows are observed over the deposits. These geophysical signatures over the Cerro Quema deposits are characteristic responses from HS epithermal gold deposits. The success of the VTEM survey points to the applicability of the regional helicopter electromagnetic, magnetic and gamma-ray spectrometry (EM-Mag-Spec) surveys for the exploration of similar HS epithermal gold deposits to depths < 500 m in weathered terrains.

  17. Airborne oceanographic lidar system

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Specifications and preliminary design of an Airborne Oceanographic Lidar (AOL) system, which is to be constructed for installation and used on a NASA Wallops Flight Center (WFC) C-54 research aircraft, are reported. The AOL system is to provide an airborne facility for use by various government agencies to demonstrate the utility and practicality of hardware of this type in the wide area collection of oceanographic data on an operational basis. System measurement and performance requirements are presented, followed by a description of the conceptual system approach and the considerations attendant to its development. System performance calculations are addressed, and the system specifications and preliminary design are presented and discussed.

  18. Airborne rain mapping radar

    NASA Technical Reports Server (NTRS)

    Wilson, W. J.; Parks, G. S.; Li, F. K.; Im, K. E.; Howard, R. J.

    1988-01-01

    An airborne scanning radar system for remote rain mapping is described. The airborne rain mapping radar is composed of two radar frequency channels at 13.8 and 24.1 GHz. The radar is proposed to scan its antenna beam over + or - 20 deg from the antenna boresight; have a swath width of 7 km; a horizontal spatial resolution at nadir of about 500 m; and a range resolution of 120 m. The radar is designed to be applicable for retrieving rainfall rates from 0.1-60 mm/hr at the earth's surface, and for measuring linear polarization signatures and raindrop's fall velocity.

  19. Ambrosia airborne pollen concentration modelling and evaluation over Europe

    NASA Astrophysics Data System (ADS)

    Hamaoui-Laguel, Lynda; Vautard, Robert; Viovy, Nicolas; Khvorostyanov, Dmitry; Colette, Augustin

    2014-05-01

    Native from North America, Ambrosia artemisiifolia L. (Common Ragweed) is an invasive annual weed introduced in Europe in the mid-nineteenth century. It has a very high spreading potential throughout Europe and releases very allergenic pollen leading to health problems for sensitive persons. Because of its health effects, it is necessary to develop modelling tools to be able to forecast ambrosia air pollen concentration and to inform allergy populations of allergenic threshold exceedance. This study is realised within the framework of the ATOPICA project (https://www.atopica.eu/) which is designed to provide first steps in tools and estimations of the fate of allergies in Europe due to changes in climate, land use and air quality. To calculate and predict airborne concentrations of ambrosia pollen, a chain of models has been built. Models have been developed or adapted for simulating the phenology (PMP phonological modelling platform), inter-annual production (ORCHIDEE vegetation model), release and airborne processes (CHIMERE chemical transport model) of ragweed pollen. Airborne pollens follow processes similar to air quality pollutants in CHIMERE with some adaptations. The detailed methodology, formulations and input data will be presented. A set of simulations has been performed to simulate airborne concentrations of pollens over long time periods on a large European domain. Hindcast simulations (2000 - 2012) driven by ERA-Interim re-analyses are designed to best simulate past periods airborne pollens. The modelled pollen concentrations are calibrated with observations and validated against additional observations. Then, 20-year long historical simulations (1986 - 2005) are carried out using calibrated ambrosia density distribution and climate model-driven weather in order to serve as a control simulation for future scenarios. By comparison with multi-annual observed daily pollen counts we have shown that the model captures well the gross features of the pollen

  20. NASA Airborne Lidar July 1991

    Atmospheric Science Data Center

    2016-05-26

    NASA Airborne Lidar July 1991 Data from the 1991 NASA Langley Airborne Lidar flights following the eruption of Pinatubo in July ... and Osborn [1992a, 1992b]. Project Title:  NASA Airborne Lidar Discipline:  Field Campaigns ...

  1. NASA Airborne Lidar May 1992

    Atmospheric Science Data Center

    2016-05-26

    NASA Airborne Lidar May 1992 An airborne Nd:YAG (532 nm) lidar was operated by the NASA Langley Research Center about a year following the June 1991 eruption of ... Osborn [1992a, 1992b].  Project Title:  NASA Airborne Lidar Discipline:  Field Campaigns ...

  2. 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.

  3. Highly sensitive and selective bioluminescence based ozone probes and their applications to detect ambient ozone.

    PubMed

    Nam, Younseok; Kim, Beom Seok; Shin, Injae

    2016-01-21

    Highly selective and sensitive bioluminescence based probes, which respond to ozone but not to other ROS, have been developed. These probes were used to determine ozone concentrations in environmental samples.

  4. Cyberinfrastructure for Airborne Sensor Webs

    NASA Technical Reports Server (NTRS)

    Freudinger, Lawrence C.

    2009-01-01

    Since 2004 the NASA Airborne Science Program has been prototyping and using infrastructure that enables researchers to interact with each other and with their instruments via network communications. This infrastructure uses satellite links and an evolving suite of applications and services that leverage open-source software. The use of these tools has increased near-real-time situational awareness during field operations, resulting in productivity improvements and the collection of better data. This paper describes the high-level system architecture and major components, with example highlights from the use of the infrastructure. The paper concludes with a discussion of ongoing efforts to transition to operational status.

  5. Temperature insensitive hysteresis free highly sensitive polymer optical fiber Bragg grating humidity sensor.

    PubMed

    Woyessa, Getinet; Nielsen, Kristian; Stefani, Alessio; Markos, Christos; Bang, Ole

    2016-01-25

    The effect of humidity on annealing of poly (methyl methacrylate) (PMMA) based microstructured polymer optical fiber Bragg gratings (mPOFBGs) and the resulting humidity responsivity are investigated. Typically annealing of PMMA POFs is done in an oven without humidity control around 80°C and therefore at low humidity. We demonstrate that annealing at high humidity and high temperature improves the performances of mPOFBGs in terms of stability and sensitivity to humidity. PMMA POFBGs that are not annealed or annealed at low humidity level will have a low and highly temperature dependent sensitivity and a high hysteresis in the humidity response, in particular when operated at high temperature. PMMA mPOFBGs annealed at high humidity show higher and more linear humidity sensitivity with negligible hysteresis. We also report how annealing at high humidity can blue-shift the FBG wavelength more than 230 nm without loss in the grating strength. PMID:26832503

  6. High sensitivity and resolution integrated optical system for portable Raman spectrometer.

    PubMed

    Tang, Ming; Wang, Xin; Xianguang, Fan; Li, Wei; Xu, Yingjie; Que, Jing; He, Jian; Zuo, Yong

    2016-09-10

    An integrated optical system with high sensitivity and resolution was presented. This was made possible by coupling a probe to a monochromator directly, using an aspheric lens and an achromatic lens in the coupling path, using a dichroic filter with high transmission and a steep transitional zone as a beam splitter, increasing the throughput of the monochromator, and optimizing its structural parameters. This optical system has a high sensitivity; the tested spectrogram of a glass rod demonstrated that the signal-to-noise ratio measured by the integrated optical system was almost 4 times as high as an independent probe and monochromator. The optical system also has the advantages of high resolution (4  cm-1 or 0.28 nm), low cost, and portable size. This work lays a good groundwork for the development of a high sensitivity, high resolution, and low cost integrated portable Raman spectrometer.

  7. High sensitivity and resolution integrated optical system for portable Raman spectrometer.

    PubMed

    Tang, Ming; Wang, Xin; Xianguang, Fan; Li, Wei; Xu, Yingjie; Que, Jing; He, Jian; Zuo, Yong

    2016-09-10

    An integrated optical system with high sensitivity and resolution was presented. This was made possible by coupling a probe to a monochromator directly, using an aspheric lens and an achromatic lens in the coupling path, using a dichroic filter with high transmission and a steep transitional zone as a beam splitter, increasing the throughput of the monochromator, and optimizing its structural parameters. This optical system has a high sensitivity; the tested spectrogram of a glass rod demonstrated that the signal-to-noise ratio measured by the integrated optical system was almost 4 times as high as an independent probe and monochromator. The optical system also has the advantages of high resolution (4  cm-1 or 0.28 nm), low cost, and portable size. This work lays a good groundwork for the development of a high sensitivity, high resolution, and low cost integrated portable Raman spectrometer. PMID:27661352

  8. The Spokane fault, Washington, Imaged with High-Resolution Airborne Magnetic Data—Implications for the 2001 Spokane Earthquake Sequence

    NASA Astrophysics Data System (ADS)

    Blakely, R. J.; Sherrod, B. L.; Weaver, C. S.; Stephenson, W. J.

    2015-12-01

    A newly acquired, high-resolution aeromagnetic survey provides insights into the near-surface lithology and tectonic structure throughout the greater Spokane area of northeastern Washington and northwestern Idaho. The region has a diverse array of magnetic lithologies, ranging from highly magnetic flood basalts of the Columbia River Basalt Group (CRBG) to weakly magnetic Mesozoic plutonic and metamorphic rocks. Faults within these magnetic lithologies produce linear magnetic anomalies that permit mapping of geologic structures over tens of kilometers. A high-amplitude, linear magnetic anomaly overlies the NW- striking Cheney fracture zone 37 km southwest of Spokane and is interpreted as a basaltic dike swarm intruded during the extensional event that opened the fractures, possibly feeder dikes for overlying CRBG flows. A sub-parallel anomaly near the town of Cheney reflects another dike swarm, likely formed during the same extensional event. The Latah fault is seen as a discontinuous alignment of magnetic anomalies extending north-northwestward from south of Spokane to the northern edge of the magnetic survey, a distance of 44 km. An arcuate, north-striking magnetic lineament ~20 km northeast of Spokane may mark the Newport fault, the detachment that promoted exhumation of the Priest River metamorphic complex. A subtle northeast-striking magnetic lineament passes through downtown Spokane and may indicate the trace of the Spokane fault, suspected of producing more than 105 small (M≤4), shallow earthquakes within Spokane city limits in 2001, accompanied by 15 mm of vertical uplift. This magnetic lineament extends 22 km and, to the northwest, merges with the lineament interpreted as the Newport fault. The Spokane fault may represent a reactivated section of the Newport fault that otherwise is not known to be active today. New LiDAR data from the Spokane area does not show distinct fault scarps associated with these magnetic anomalies, but a more comprehensive

  9. Comparison of airborne and spaceborne TIR data for studying volcanic geothermal areas

    NASA Astrophysics Data System (ADS)

    Vaughan, R. G.; Heasler, H.; Jaworowski, C.; Bergfeld, D.; Evans, W.

    2015-12-01

    Mapping and quantifying the surface expression of geothermal heat flux in volcanic geothermal areas is important for establishing baseline thermal activity to better detect and understand any future changes that may be related to hydrothermal or volcanic processes, or human activities. Volcanic geothermal areas are often too large and inaccessible for only field-based thermal monitoring, so thermal infrared (TIR) remote sensing tools are also used. High resolution (sub-meter) airborne TIR imagery can be used for detailed, quantitative analyses of small, subtle geothermal features. Airborne data acquisitions have the advantage of being able to be acquired under ideal conditions (e.g., predawn, cloud-free), but the disadvantage of high costs - thus precluding high-frequency monitoring. Satellite-based TIR data from the Landsat 8 platform are freely available and can be acquired regularly for change detection, but are acquired with coarser spatial resolution (e.g., 100-m pixels), and thus are not as sensitive to subtle thermal characteristics. Two geothermal areas with clear, nighttime TIR data from nearly concurrent (within days) airborne and spaceborne instruments were investigated: Norris Geyser Basin in Yellowstone National Park, WY; and the Casa Diablo geothermal field, near Mammoth Lakes, CA. At Norris Geyser Basin, the area covered by high-resolution airborne TIR imagery is almost entirely geothermally heated ground, with hundreds of fumaroles, hot springs, and thermal drainages - although some non-geothermal background is exposed. With the coarser resolution Landsat 8 data, there are thermal variations within the smaller area covered by the airborne data, but the entire area appears to be thermally anomalous with respect to the non-geothermal background outside the basin. In the geothermal field around the Casa Diablo geothermal site, there are numerous, small areas of geothermal heating that are clearly distinguishable above the background by the high

  10. Bathymetry of Patagonia glacier fjords and glacier ice thickness from high-resolution airborne gravity combined with other data

    NASA Astrophysics Data System (ADS)

    An, L.; Rignot, E.; Rivera, A.; Bunetta, M.

    2012-12-01

    The North and South Patagonia Ice fields are the largest ice masses outside Antarctica in the Southern Hemisphere. During the period 1995-2000, these glaciers lost ice at a rate equivalent to a sea level rise of 0.105 ± 0.001 mm/yr. In more recent years, the glaciers have been thinning more quickly than can be explained by warmer air temperatures and decreased precipitation. A possible cause is an increase in flow speed due to enhanced ablation of the submerged glacier fronts. To understand the dynamics of these glaciers and how they change with time, it is critical to have a detailed view of their ice thickness, the depth of the glacier bed below sea or lake level, how far inland these glaciers remain below sea or lake level, and whether bumps or hollows in the bed may slow down or accelerate their retreat. A grid of free-air gravity data over the Patagonia Glaciers was collected in May 2012 and October 2012, funded by the Gordon and Betty Moore Foundation (GBMF) to measure ice thickness and sea floor bathymetry. This survey combines the Sander Geophysics Limited (SGL) AIRGrav system, SGL laser altimetry and Chilean CECS/UCI ANDREA-2 radar. To obtain high-resolution and high-precision gravity data, the helicopter operates at 50 knots (25.7 m/s) with a grid spacing of 400m and collects gravity data at sub mGal level (1 Gal =1 Galileo = 1 cm/s2) near glacier fronts. We use data from the May 2012 survey to derive preliminarily high-resolution, high-precision thickness estimates and bathymetry maps of Jorge Montt Glacier and San Rafael Glacier. Boat bathymetry data is used to optimize the inversion of gravity over water and radar-derived thickness over glacier ice. The bathymetry maps will provide a breakthrough in our knowledge of the ice fields and enable a new era of glacier modeling and understanding that is not possible at present because ice thickness is not known.

  11. 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.; Kittaka, C.; Hostetler, C. A.; Hair, J. W.; Obland, M. D.; Rogers, R. R.; Cook, A. L.; Haper, D. B.

    2008-01-01

    Aerosol extinction profiles are derived from backscatter data by constraining the retrieval with column aerosol optical thickness (AOT), for example from coincident MODIS observations and without reliance on a priori assumptions about aerosol type or optical properties. The backscatter data were acquired with the NASA Langley High Spectral Resolution Lidar (HSRL). The HSRL also simultaneously measures extinction independently, thereby providing an ideal data set for evaluating the constrained retrieval of extinction from backscatter. We will show constrained extinction retrievals using various sources of column AOT, and examine comparisons with the HSRL extinction measurements and with a similar retrieval using data from the CALIOP lidar on the CALIPSO satellite.

  12. Use of Very High-Resolution Airborne Images to Analyse 3d Canopy Architecture of a Vineyard

    NASA Astrophysics Data System (ADS)

    Burgos, S.; Mota, M.; Noll, D.; Cannelle, B.

    2015-08-01

    Differencing between green cover and grape canopy is a challenge for vigour status evaluation in viticulture. This paper presents the acquisition methodology of very high-resolution images (4 cm), using a Sensefly Swinglet CAM unmanned aerial vehicle (UAV) and their processing to construct a 3D digital surface model (DSM) for the creation of precise digital terrain models (DTM). The DTM was obtained using python processing libraries. The DTM was then subtracted to the DSM in order to obtain a differential digital model (DDM) of a vineyard. In the DDM, the vine pixels were then obtained by selecting all pixels with an elevation higher than 50 [cm] above the ground level. The results show that it was possible to separate pixels from the green cover and the vine rows. The DDM showed values between -0.1 and + 1.5 [m]. A manually delineation of polygons based on the RGB image belonging to the green cover and to the vine rows gave a highly significant differences with an average value of 1.23 [m] and 0.08 [m] for the vine and the ground respectively. The vine rows elevation is in good accordance with the topping height of the vines 1.35 [m] measured on the field. This mask could be used to analyse images of the same plot taken at different times. The extraction of only vine pixels will facilitate subsequent analyses, for example, a supervised classification of these pixels.

  13. High-sensitivity strain sensor based on inflated long period fiber grating.

    PubMed

    Zhong, Xiaoyong; Wang, Yiping; Qu, Junle; Liao, Changrui; Liu, Shen; Tang, Jian; Wang, Qiao; Zhao, Jing; Yang, Kaiming; Li, Zhengyong

    2014-09-15

    We demonstrated a high-sensitivity strain sensor based on an inflated long period fiber grating (I-LPFG). The I-LPFG was inscribed, for the first time to the best of our knowledge, by use of the pressure-assisted CO(2) laser beam scanning technique to inflate periodically air holes of a photonic crystal fiber. Such periodic inflations enhanced the sensitivity of the LPFG-based strain sensor to -5.62 pm/με. After high temperature annealing, the I-LPFG achieved a good repeatability and stability of temperature response with a sensitivity of 11.92 pm/°C. PMID:26466298

  14. Making sense of high sensitivity troponin assays and their role in clinical care.

    PubMed

    Daniels, Lori B

    2014-04-01

    Cardiac troponin assays have an established and undisputed role in the diagnosis and risk stratification of patients with acute myocardial infarction. As troponin assays gets more sensitive and more precise, the number of potential uses has rapidly expanded, but the use of this test has also become more complicated and controversial. Highly sensitive troponin assays can now detect troponin levels in most individuals, but accurate interpretation of these levels requires a clear understanding of the assay in the context of the clinical scenario. This paper provides a practical and up-to-date overview of the uses of highly sensitive troponin assays for diagnosis, prognosis, and risk stratification in clinical practice.

  15. Airborne pollutant characteristics in an urban, industrial and agricultural complex metroplex with high emission loading and ammonia concentration.

    PubMed

    Tsai, Jiun-Horng; Chang, Li-Peng; Chiang, Hung-Lung

    2014-10-01

    The size distribution of particulate mass and water-soluble ionic constituents and their gaseous precursors was investigated in a subtropical area, southern Taiwan. Field sampling and chemical analysis of particulate matter (PM) were conducted using a Micro Orifice Uniform Deposition Impactor (MOUDI) and a Nano-MOUDI, and gaseous pollutants were determined by a denuder-filter pack system. PM size mass distribution, mass concentration and ionic species concentration were measured during the day and at night in the winter and summer. Average PM concentrations in the winter were as high as 132 ± 42 μg/m(3), and PM mass concentrations in the summer were as low as 38 ± 19 μg/m(3). Generally, PM concentration was 111 ± 60 μg/m(3) at night, which was 20% higher than that in the daytime. The size-segregated mass distribution of PM mass concentration was over 85% in the 0.1-3.2 μm range. Ammonium, nitrate, and sulfate were the dominant water-soluble ionic species in PM, contributing 34%-48% of PM mass. High ammonia (12.9-49 μg/m(3)) and SO2 (2.6-27 μg/m(3)) were observed in the gas precursors. The molar ratio [Formula: see text] was 3.18 ± 1.20 at PM1.0, which indicated that the PM was rich in ammonium. Therefore, the excess ammonium could neutralize nitrate to form ammonium nitrate, after the more stable ammonium sulfate and ammonium bisulfate formation. PMID:25037046

  16. Airborne pollutant characteristics in an urban, industrial and agricultural complex metroplex with high emission loading and ammonia concentration.

    PubMed

    Tsai, Jiun-Horng; Chang, Li-Peng; Chiang, Hung-Lung

    2014-10-01

    The size distribution of particulate mass and water-soluble ionic constituents and their gaseous precursors was investigated in a subtropical area, southern Taiwan. Field sampling and chemical analysis of particulate matter (PM) were conducted using a Micro Orifice Uniform Deposition Impactor (MOUDI) and a Nano-MOUDI, and gaseous pollutants were determined by a denuder-filter pack system. PM size mass distribution, mass concentration and ionic species concentration were measured during the day and at night in the winter and summer. Average PM concentrations in the winter were as high as 132 ± 42 μg/m(3), and PM mass concentrations in the summer were as low as 38 ± 19 μg/m(3). Generally, PM concentration was 111 ± 60 μg/m(3) at night, which was 20% higher than that in the daytime. The size-segregated mass distribution of PM mass concentration was over 85% in the 0.1-3.2 μm range. Ammonium, nitrate, and sulfate were the dominant water-soluble ionic species in PM, contributing 34%-48% of PM mass. High ammonia (12.9-49 μg/m(3)) and SO2 (2.6-27 μg/m(3)) were observed in the gas precursors. The molar ratio [Formula: see text] was 3.18 ± 1.20 at PM1.0, which indicated that the PM was rich in ammonium. Therefore, the excess ammonium could neutralize nitrate to form ammonium nitrate, after the more stable ammonium sulfate and ammonium bisulfate formation.

  17. Toward high-sensitivity and high-resolution submillimeter-wave video imaging

    NASA Astrophysics Data System (ADS)

    Heinz, Erik; May, Torsten; Born, Detlef; Zieger, Gabriel; Thorwirth, Günter; Anders, Solveig; Zakosarenko, Vyacheslav; Krause, Torsten; Krüger, André; Schulz, Marco; Meyer, Hans-Georg; Schubert, Marco; Starkloff, Michael

    2011-11-01

    Against a background of newly emerged security threats, the well-established idea of utilizing submillimeter-wave radiation for personal security screening applications has recently evolved into a promising technology. Possible application scenarios demand sensitive, fast, flexible and high-quality imaging techniques. At present, best results are obtained by passive imaging using cryogenic microbolometers as radiation detectors. Building upon the concept of a passive submillimeter-wave stand-off video camera introduced previously, we present the evolution of this concept into a practical application-ready imaging device. This has been achieved using a variety of measures such as optimizing the detector parameters, improving the scanning mechanism, increasing the sampling speed, and enhancing the image generation software. The camera concept is based on a Cassegrain-type mirror optics, an optomechanical scanner, an array of 20 superconducting transition-edge sensors operated at a temperature of 450 to 650 mK, and a closed-cycle cryogen-free cooling system. The main figures of the system include: a frequency band of 350+/-40 GHz, an object distance of 7 to 10 m, a circular field of view of 1.05 m diameter, and a spatial resolution in the image center of 2 cm at 8.5 m distance, a noise equivalent temperature difference of 0.1 to 0.4 K, and a maximum frame rate of 10 Hz.

  18. High-throughput, Highly Sensitive Analyses of Bacterial Morphogenesis Using Ultra Performance Liquid Chromatography.

    PubMed

    Desmarais, Samantha M; Tropini, Carolina; Miguel, Amanda; Cava, Felipe; Monds, Russell D; de Pedro, Miguel A; Huang, Kerwyn Casey

    2015-12-25

    The bacterial cell wall is a network of glycan strands cross-linked by short peptides (peptidoglycan); it is responsible for the mechanical integrity of the cell and shape determination. Liquid chromatography can be used to measure the abundance of the muropeptide subunits composing the cell wall. Characteristics such as the degree of cross-linking and average glycan strand length are known to vary across species. However, a systematic comparison among strains of a given species has yet to be undertaken, making it difficult to assess the origins of variability in peptidoglycan composition. We present a protocol for muropeptide analysis using ultra performance liquid chromatography (UPLC) and demonstrate that UPLC achieves resolution comparable with that of HPLC while requiring orders of magnitude less injection volume and a fraction of the elution time. We also developed a software platform to automate the identification and quantification of chromatographic peaks, which we demonstrate has improved accuracy relative to other software. This combined experimental and computational methodology revealed that peptidoglycan composition was approximately maintained across strains from three Gram-negative species despite taxonomical and morphological differences. Peptidoglycan composition and density were maintained after we systematically altered cell size in Escherichia coli using the antibiotic A22, indicating that cell shape is largely decoupled from the biochemistry of peptidoglycan synthesis. High-throughput, sensitive UPLC combined with our automated software for chromatographic analysis will accelerate the discovery of peptidoglycan composition and the molecular mechanisms of cell wall structure determination.

  19. High-resolution and high-intensity neutron diffractometer with linear position-sensitive detector

    NASA Astrophysics Data System (ADS)

    Lee, Chang-Hee; Moon, Myung-Kook; Em, V. T.; Choi, Young-Nam; Oh, Hwa-Suk; Nam, Uk-Won

    2003-08-01

    The characteristics of a neutron diffractometer using a 3He one-dimensional position-sensitive detector (PSD) with delay line readout, a 200 (length) × 100 (height) mm 2 active window and 2.5 mm spatial resolution have been studied and compared with those of the High-Resolution Powder Diffractometer (HRPD) of KAERI with 32 3He conventional tube (∅50 mm) detectors and Soller collimators (10') before detectors. For the sample to PSD distance R=1200 mm, the PSD subtends 8° angle of 2 θ and provides the resolution and the peak-to-background ratio close to that for HRPD. Time for scanning (with the same statistics) of a 0-160° interval is about 1.6 times longer and the multi-PSD system providing efficiency about 10 times higher than HRPD is proposed. Because of the small angle subtended by the PSD, the parasitic peaks from the sample environment are eliminated and operation without an oscillating radial collimator is possible. Additionally, the proposed diffractometer has an advantage for small samples.

  20. Forest fuel treatment detection using multi-temporal airborne Lidar data and high resolution aerial imagery ---- A case study at Sierra Nevada, California

    NASA Astrophysics Data System (ADS)

    Su, Y.; Guo, Q.; Collins, B.; Fry, D.; Kelly, M.

    2014-12-01

    Forest fuel treatments (FFT) are often employed in Sierra Nevada forest (located in California, US) to enhance forest health, regulate stand density, and reduce wildfire risk. However, there have been concerns that FFTs may have negative impacts on certain protected wildlife species. Due to the constraints and protection of resources (e.g., perennial streams, cultural resources, wildlife habitat, etc.), the actual FFT extents are usually different from planned extents. Identifying the actual extent of treated areas is of primary importance to understand the environmental influence of FFTs. Light detection and ranging (Lidar) is a powerful remote sensing technique that can provide accurate forest structure measurements, which provides great potential to monitor forest changes. This study used canopy height model (CHM) and canopy cover (CC) products derived from multi-temporal airborne Lidar data to detect FFTs by an approach combining a pixel-wise thresholding method and a object-of-interest segmentation method. We also investigated forest change following the implementation of landscape-scale FFT projects through the use of normalized difference vegetation index (NDVI) and standardized principle component analysis (PCA) from multi-temporal high resolution aerial imagery. The same FFT detection routine was applied on the Lidar data and aerial imagery for the purpose of comparing the capability of Lidar data and aerial imagery on FFT detection. Our results demonstrated that the FFT detection using Lidar derived CC products produced both the highest total accuracy and kappa coefficient, and was more robust at identifying areas with light FFTs. The accuracy using Lidar derived CHM products was significantly lower than that of the result using Lidar derived CC, but was still slightly higher than using aerial imagery. FFT detection results using NDVI and standardized PCA using multi-temporal aerial imagery produced almost identical total accuracy and kappa coefficient

  1. Advanced Algorithms and High-Performance Testbed for Large-Scale Site Characterization and Subsurface Target Detecting Using Airborne Ground Penetrating SAR

    NASA Technical Reports Server (NTRS)

    Fijany, Amir; Collier, James B.; Citak, Ari

    1997-01-01

    A team of US Army Corps of Engineers, Omaha District and Engineering and Support Center, Huntsville, let Propulsion Laboratory (JPL), Stanford Research Institute (SRI), and Montgomery Watson is currently in the process of planning and conducting the largest ever survey at the Former Buckley Field (60,000 acres), in Colorado, by using SRI airborne, ground penetrating, Synthetic Aperture Radar (SAR). The purpose of this survey is the detection of surface and subsurface Unexploded Ordnance (UXO) and in a broader sense the site characterization for identification of contaminated as well as clear areas. In preparation for such a large-scale survey, JPL has been developing advanced algorithms and a high-performance restbed for processing of massive amount of expected SAR data from this site. Two key requirements of this project are the accuracy (in terms of UXO detection) and speed of SAR data processing. The first key feature of this testbed is a large degree of automation and a minimum degree of the need for human perception in the processing to achieve an acceptable processing rate of several hundred acres per day. For accurate UXO detection, novel algorithms have been developed and implemented. These algorithms analyze dual polarized (HH and VV) SAR data. They are based on the correlation of HH and VV SAR data and involve a rather large set of parameters for accurate detection of UXO. For each specific site, this set of parameters can be optimized by using ground truth data (i.e., known surface and subsurface UXOs). In this paper, we discuss these algorithms and their successful application for detection of surface and subsurface anti-tank mines by using a data set from Yuma proving Ground, A7, acquired by SRI SAR.

  2. Planetary Boundary Layer (PBL) Heights Derived From NASA Langley Airborne High Spectral Resolution Lidar (HSRL) Data Acquired During TexAQS/GoMACCS, CHAPS, and MILAGRO

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

    The NASA Langley Research Center airborne High Spectral Resolution Lidar (HSRL) was deployed on the NASA Langley B-200 King Air aircraft in the Mexico City metropolitan area during the Mega-city Initiative: Local and Global Research Observations (MILAGRO) campaign in March 2006; in the Houston metropolitan area during the Texas Air Quality Study (TexAQS)/Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) in August and September 2006; and in the Oklahoma City area during Cumulus Humilis Aerosol Processing Study (CHAPS) in June 2007. The HSRL instrument measures profiles of aerosol extinction, backscatter and depolarization. The height of the Planetary Boundary Layer was derived by identifying sharp gradients in the HSRL 532-nm aerosol backscatter signal profiles using an automated technique based on Brooks (2003) [I.M. Brooks, Finding Boundary Layer Top: Application of Wavelet Covariance Transform to Lidar Backscatter Profiles. Journal of Atmospheric and Oceanic Technology 20, 1092-1105, 2003]. The technique uses a Haar wavelet covariance transform with multiple wavelet dilation values to adapt to non-ideal conditions where there can be gradients in the background signals and the boundary layer can be ill defined. The technique also identifies the top and bottom of the transition (i.e. entrainment) zone. We have further modified the algorithm to find PBL heights using HSRL backscatter data acquired during GoMACCS and MILAGRO, where complex terrain and overlying aerosol layers further complicate identifying the boundary layer. In addition, PBL heights are derived from HSRL backscatter data acquired during the CHAPS campaign, in another urban environment where the terrain is not as complex. We will describe the algorithm modifications we have made and show boundary layer heights and transition zone thicknesses for HSRL measurements over the Oklahoma City, Houston, and Mexico City areas during CHAPS, TexAQS/GoMACCS, and MILAGRO.

  3. Advanced algorithms and high-performance testbed for large-scale site characterization and subsurface target detection using airborne ground-penetrating SAR

    NASA Astrophysics Data System (ADS)

    Fijany, Amir; Collier, James B.; Citak, Ari

    1999-08-01

    A team of US Army Corps of Engineers, Omaha District and Engineering and Support Center, Huntsville, JPL, Stanford Research Institute (SRI), and Montgomery Watson is currently in the process of planning and conducting the largest ever survey at the Former Buckley Field, in Colorado, by using SRI airborne, ground penetrating, SAR. The purpose of this survey is the detection of surface and subsurface Unexploded Ordnance (UXO) and in a broader sense the site characterization for identification of contaminated as well as clear areas. In preparation for such a large-scale survey, JPL has been developing advanced algorithms and a high-performance testbed for processing of massive amount of expected SAR data from this site. Two key requirements of this project are the accuracy and speed of SAR data processing. The first key feature of this testbed is a large degree of automation and maximum degree of the need for human perception in the processing to achieve an acceptable processing rate of several hundred acres per day. For accuracy UXO detection, novel algorithms have been developed and implemented. These algorithms analyze dual polarized SAR data. They are based on the correlation of HH and VV SAR data and involve a rather large set of parameters for accurate detection of UXO. For each specific site, this set of parameters can be optimized by using ground truth data. In this paper, we discuss these algorithms and their successful application for detection of surface and subsurface anti-tank mines by using a data set from Yuma Proving Ground, AZ, acquired by SRI SAR.

  4. Assessing Aerosol Mixed Layer Heights from the NASA Larc Airborne High Spectral Resolution Lidar (HSRL) during the Discover-AQ Field Campaigns

    NASA Astrophysics Data System (ADS)

    Scarino, A. J.; Ferrare, R. A.; Burton, S. P.; Hostetler, C. A.; Hair, J. W.; Rogers, R. R.; Berkoff, T.; Sawamura, P.; Collins, J. E., Jr.; Seaman, S. T.; Cook, A. L.; Harper, D. B.; Follette-Cook, M. B.; daSilva, A.; Randles, C. A.

    2014-12-01

    The first- and second-generation NASA airborne High Spectral Resolution Lidars (HSRL-1 and HSRL-2) have been deployed on board the NASA Langley Research Center King Air aircraft during the Deriving Information on Surface Conditions from Column and VERtically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) field campaigns. These included deployments during July 2011 over Washington, D.C. and Baltimore, MD, during January and February 2013 over the San Joaquin Valley of California, during September 2013 over Houston, TX and during July and August 2014 over Denver, CO. Measurements of aerosol extinction, backscatter, and depolarization are available from both HSRL-1 and HSRL-2 in coordination with other participating research aircraft and ground sites. These measurements constitute a diverse data set for use in characterizing the spatial and temporal distribution of aerosols, aerosol optical thickness (AOT), as well as the mixed layer (ML) height. Analysis of the ML height at these four locations is presented, including temporal and horizontal variability and comparisons between land and water, including the Chesapeake Bay and Galveston Bay. Using the ML heights, the distribution of AOT relative to the ML heights is determined, which is relevant for assessing the long-range transport of aerosols. The ML heights are also used to help relate column AOT measurements and extinction profiles to surface PM2.5 concentrations. The HSRL ML heights are also used to evaluate the performance in simulating the temporal and spatial variability of ML heights from both chemical regional models and global forecast models.

  5. Super High Resolution Airborne Remote Sensing for Evaluating the Decomposition Function of Ecosystem of Temperate Forest in Japan

    NASA Astrophysics Data System (ADS)

    Suzuki, R.; Fadaei, H.; Ishii, R.; Nagai, S.; Okabe, K.; Yamashita, S.; Taki, H.; Honda, Y.; Kajiwara, K.

    2013-12-01

    Forest ecosystem is sustained by nutrients cycle among trees, floor vegetation, litter, and soil etc. One of important driving mechanisms for such nutrients cycle is the decomposition of the fallen trees by fungi, and this process would play an important function in the biogeochemical cycle of the environment. This study challenged to identify the position and size of fallen trees in a temperate forest in Japan based on super high resolution (less than 1cm) visual images taken from a camera aboard a helicopter. Field campaign was carried out on November 29, 2011 at the experimental forest (6 ha, 300m x 200m, 36° 56' 10.5'N, 140° 35' 16.5'E) in Kitaibaraki, Ibaraki, Japan. According to the census survey of the forest, deciduous broad leave trees are dominant. There was almost no leaf in the forest crown on the day of the field campaign, and that brought a high visibility of the floor from the sky. The topography of the forest site is characterized by a small valley with a river flowing north to south at its bottom. An unmanned helicopter (Yamaha RMAX G1) flew over the forest in north-south lines with a speed of 3m/s at height of 30-70m from the ground surface. The interval between adjacent two lines was 20m. A consumer grade camera (Canon EOS Kiss X5 with 55mm lens; 5184 x 3456 pixels) was fixed with the vertically looking down direction on the helicopter. The camera took forest images with 5 seconds interval. The helicopter was also equipped by a laser range finder (LRF) (SkEyesBOX MP-1). Based on the point cloud created by the LRF measurement, 1 x 1m digital elevation model (DEM) of the ground surface was established by finding the lowest point value of the point cloud in each 1 x 1m grid of the forest. The forest was covered by 211 images taken by the camera. Each image was orthorectified by using the DEM and the data of the position and orientations of the helicopter, and then they were mosaicked into one image. Fallen trees with the diameter more than 10cm

  6. Evaluation of Surface Energy Balance models for mapping evapotranspiration using very high resolution airborne remote sensing data

    NASA Astrophysics Data System (ADS)

    Paul, George

    Agriculture is the largest (90%) consumer of all fresh water in the world. The consumptive use of water by vegetation represented by the process evapotranspiration (ET) has a vital role in the dynamics of water, carbon and energy fluxes of the biosphere. Consequently, mapping ET is essential for making water a sustainable resource and also for monitoring ecosystem response to water stress and changing climate. Over the past three decades, numerous thermal remote sensing based ET mapping algorithms were developed and these have brought a significant theoretical and technical advancement in the spatial modeling of ET. Though these algorithms provided a robust, economical, and efficient tool for ET estimations at field and regional scales, yet the uncertainties in flux estimations were large, making evaluation a difficult task. The main objective of this study was to evaluate and improve the performance of widely used remote sensing based energy balance models, namely: the Surface Energy Balance Algorithm for Land (SEBAL), Mapping Evapotranspiration at high Resolution and with Internalized Calibration (METRIC), and Surface Energy Balance System (SEBS). Data used in this study was collected as part of a multi-disciplinary and multi-institutional field campaign BEAREX (Bushland Evapotranspiration and Agricultural Remote Sensing Experiment) that was conducted during 2007 and 2008 summer cropping seasons at the USDA-ARS Conservation and Production Research Laboratory (CPRL) in Bushland, Texas. Seventeen high resolution remote sensing images taken from multispectral sensors onboard aircraft and field measurements of the agro-meteorological variables from the campaign were used for model evaluation and improvement. Overall relative error measured in terms of mean absolute percent difference (MAPD) for instantaneous ET (mm h -1) were 22.7%, 23.2%, and 12.6% for SEBAL, METRIC, and SEBS, respectively. SEBAL and METRIC performances for irrigated fields representing higher ET

  7. Fast Airborne Aerosol Size and Chemistry Measurements with the High Resolution Aerosol Mass Spectrometer during the MILAGRO Campaign

    NASA Technical Reports Server (NTRS)

    DeCarlo, P. F.; Dunlea, E. J.; Kimmel, J. R.; Aiken, A. C.; Sueper, D.; Crounse, J.; Wennberg, P. O.; Emmons, L.; Shinozuka, Y.; Clarke, A.; Zhou, J.; Tomlinson, J.; Collins,D. R.; Knapp, D.; Weinheimer, A. J.; Montzka,D. D.; Campos,T.; Jimenez, J. L.

    2007-01-01

    The concentration, size, and composition of non-refractory submicron aerosol (NR-PM(sub l)) was measured over Mexico City and central Mexico with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) onboard the NSF/NCAR C-130 aircraft as part of the MILAGRO field campaign. This was the first aircraft deployment of the HR-ToF-AMS. During the campaign the instrument performed very well, and provided 12 s data. The aerosol mass from the AMS correlates strongly with other aerosol measurements on board the aircraft. Organic aerosol (OA) species dominate the NR-PM(sub l) mass. OA correlates strongly with CO and HCN indicating that pollution (mostly secondary OA, SOA) and biomass burning (BB) are the main OA sources. The OA to CO ratio indicates a typical value for aged air of around 80 microg/cubic m (STP) ppm(exp -1). This is within the range observed in outflow from the Northeastern US, which could be due to a compensating effect between higher BB but lower biogenic VOC emissions during this study. The O/C atomic ratio for OA is calculated from the HR mass spectra and shows a clear increase with photochemical age, as SOA forms rapidly and quickly overwhelms primary urban OA, consistent with Volkamer et al. (2006) and Kleinman et al. (2008). The stability of the OA/CO while O/C increases with photochemical age implies a net loss of carbon from the OA. BB OA is marked by signals at m/z 60 and 73, and also by a signal enhancement at large m/z indicative of larger molecules or more resistance to fragmentation. The main inorganic components show different spatial patterns and size distributions. Sulfate is regional in nature with clear volcanic and petrochemical/power plant sources, while the urban area is not a major regional source for this species. Nitrate is enhanced significantly in the urban area and immediate outflow, and is strongly correlated with CO indicating a strong urban source. The importance of nitrate decreases with distance from the city

  8. Airborne Fraunhofer Line Discriminator

    NASA Technical Reports Server (NTRS)

    Gabriel, F. C.; Markle, D. A.

    1969-01-01

    Airborne Fraunhofer Line Discriminator enables prospecting for fluorescent materials, hydrography with fluorescent dyes, and plant studies based on fluorescence of chlorophyll. Optical unit design is the coincidence of Fraunhofer lines in the solar spectrum occurring at the characteristic wavelengths of some fluorescent materials.

  9. Recognizing Airborne Hazards.

    ERIC Educational Resources Information Center

    Schneider, Christian M.

    1990-01-01

    The heating, ventilating, and air conditioning (HVAC) systems in older buildings often do not adequately handle air-borne contaminants. Outlines a three-stage Indoor Air Quality (IAQ) assessment and describes a case in point at a Pittsburgh, Pennsylvania, school. (MLF)

  10. Airborne asbestos in buildings.

    PubMed

    Lee, R J; Van Orden, D R

    2008-03-01

    The concentration of airborne asbestos in buildings nationwide is reported in this study. A total of 3978 indoor samples from 752 buildings, representing nearly 32 man-years of sampling, have been analyzed by transmission electron microscopy. The buildings that were surveyed were the subject of litigation related to suits alleging the general building occupants were exposed to a potential health hazard as a result the presence of asbestos-containing materials (ACM). The average concentration of all airborne asbestos structures was 0.01structures/ml (s/ml) and the average concentration of airborne asbestos > or = 5microm long was 0.00012fibers/ml (f/ml). For all samples, 99.9% of the samples were <0.01 f/ml for fibers longer than 5microm; no building averaged above 0.004f/ml for fibers longer than 5microm. No asbestos was detected in 27% of the buildings and in 90% of the buildings no asbestos was detected that would have been seen optically (> or = 5microm long and > or = 0.25microm wide). Background outdoor concentrations have been reported at 0.0003f/ml > or = 5microm. These results indicate that in-place ACM does not result in elevated airborne asbestos in building atmospheres approaching regulatory levels and that it does not result in a significantly increased risk to building occupants.

  11. Dual channel airborne hygrometer for climate research

    NASA Astrophysics Data System (ADS)

    Tatrai, David; Gulyas, Gabor; Bozoki, Zoltan; Szabo, Gabor

    2015-04-01

    Airborne hygrometry has an increasing role in climate research and nowadays the determination of cloud content especially of cirrus clouds is gaining high interest. The greatest challenges for such measurements are being used from ground level up to the lower stratosphere with appropriate precision and accuracy the low concentration and varying environment pressure. Such purpose instrument was probably presented first by our research group [1-2]. The development of the system called WaSUL-Hygro and some measurement results will be introduced. The measurement system is based on photoacoustic spectroscopy and contains two measuring cells, one is used to measure water vapor concentration which is typically sampled by a sideward or backward inlet, while the second one measures total water content (water vapor plus ice crystals) after evaporation in a forward facing sampler. The two measuring cells are simultaneously illuminated through with one distributed feedback diode laser (1371 or 1392 nm). Two early versions have been used within the CARIBIC project. During the recent years, efforts were made to turn the system into a more reliable and robust one [3]. The first important development was the improvement of the wavelength stabilization method of the applied laser. As a result the uncertainty of the wavelength is less than 40fm, which corresponds to less than 0.05% of PA signal uncertainty. This PA signal uncertainty is lower than the noise level of the system itself. The other main development was the improvement of the concentration determination algorithm. For this purpose several calibration and data evaluation methods were developed, the combination of the latest ones have made the system traceable to the humidity generator applied during the calibration within 1.5% relative deviation or within noise level, whichever is greater. The improved system was several times blind tested at the Environmental Simulation Facility (Forschungszentrum Jülich, Germany) in

  12. Sensitivity of the High Altitude Water Cherenkov Experiment to observe Gamma-Ray Bursts

    NASA Astrophysics Data System (ADS)

    González, M. M.

    Ground based telescopes have marginally observed very high energy emission (>100GeV) from gamma-ray bursts(GRB). For instance, Milagrito observed GRB970417a with a significance of 3.7 sigmas over the background. Milagro have not yet observed TeV emission from a GRB with its triggered and untriggered searches or GeV emission with a triggered search using its scalers. These results suggest the need of new observatories with higher sensitivity to transient sources. The HAWC (High Altitute Water Cherenkov) observatory is proposed as a combination of the Milagro tecnology with a very high altitude (>4000m over see level) site. The expected HAWC sensitivity for GRBs is at least >10 times the Milagro sensitivity. In this work HAWC sensitivity for GRBs is discussed for different detector configurations such as altitude, distance between PMTs, depth under water of PMTs, number of PMTs required for a trigger, etc.

  13. High-sensitivity temperature sensor based on a droplet-like fiber circle.

    PubMed

    Xie, Jianglei; Xu, Ben; Li, Yi; Kang, Juan; Shen, Changyu; Wang, Jianfeng; Jin, Yongxing; Liu, Honglin; Ni, Kai; Dong, Xinyong; Zhao, Chunliu; Jin, Shangzhong

    2014-06-20

    A low-cost yet high-sensitivity temperature fiber sensor is proposed and demonstrated in this paper. A single-mode fiber with coating is simply bent in a droplet-like circle with a radius of several millimeters. The strong bending induces mode interferences between the silica core mode and the excited modes propagating in the polymer coating. Many resonant dips were observed in the transmission spectra and are found to shift to a shorter wavelength with the increase of environmental temperature. Our linear fitting result of the experimental data shows that the proposed sensor presents high temperature sensitivity up to -3.102  nm/°C, which is even comparable with sensors based on selective liquid-filled photonic crystal fibers. Such high temperature sensitivity results from the large thermo-optical coefficient difference between the silica core and the polymer coating. The influence of a circle radius to the sensitivities is also discussed. PMID:24979444

  14. Fano resonance-based highly sensitive, compact temperature sensor on thin film lithium niobate.

    PubMed

    Qiu, Wentao; Ndao, Abdoulaye; Vila, Venancio Calero; Salut, Roland; Courjal, Nadège; Baida, Fadi Issam; Bernal, Maria-Pilar

    2016-03-15

    In this Letter, we report a Fano resonance-based highly sensitive and compact temperature sensor fabricated on thin film lithium niobate (TFLN) Suzuki phase lattice (SPL) photonic crystal. The experimental sensitivity is estimated to be 0.77 nm/°C with a photonic crystal size of only 25  μm × 24  μm. This sensitivity is 38 times larger than the intrinsic one of lithium niobate which is 0.02 nm/°C. The demonstrated sharp and high extinction ratio characteristics of the Fano lineshape resonance could be an excellent candidate in developing a high sensitivity temperature sensor, electric field sensor, etc. PMID:26977645

  15. Coupled Aerodynamic and Structural Sensitivity Analysis of a High-Speed Civil Transport

    NASA Technical Reports Server (NTRS)

    Mason, B. H.; Walsh, J. L.

    2001-01-01

    An objective of the High Performance Computing and Communication Program at the NASA Langley Research Center is to demonstrate multidisciplinary shape and sizing optimization of a complete aerospace vehicle configuration by using high-fidelity, finite-element structural analysis and computational fluid dynamics aerodynamic analysis. In a previous study, a multi-disciplinary analysis system for a high-speed civil transport was formulated to integrate a set of existing discipline analysis codes, some of them computationally intensive, This paper is an extension of the previous study, in which the sensitivity analysis for the coupled aerodynamic and structural analysis problem is formulated and implemented. Uncoupled stress sensitivities computed with a constant load vector in a commercial finite element analysis code are compared to coupled aeroelastic sensitivities computed by finite differences. The computational expense of these sensitivity calculation methods is discussed.

  16. International Symposium on Airborne Geophysics

    NASA Astrophysics Data System (ADS)

    Mogi, Toru; Ito, Hisatoshi; Kaieda, Hideshi; Kusunoki, Kenichiro; Saltus, Richard W.; Fitterman, David V.; Okuma, Shigeo; Nakatsuka, Tadashi

    2006-05-01

    Airborne geophysics can be defined as the measurement of Earth properties from sensors in the sky. The airborne measurement platform is usually a traditional fixed-wing airplane or helicopter, but could also include lighter-than-air craft, unmanned drones, or other specialty craft. The earliest history of airborne geophysics includes kite and hot-air balloon experiments. However, modern airborne geophysics dates from the mid-1940s when military submarine-hunting magnetometers were first used to map variations in the Earth's magnetic field. The current gamut of airborne geophysical techniques spans a broad range, including potential fields (both gravity and magnetics), electromagnetics (EM), radiometrics, spectral imaging, and thermal imaging.

  17. Looking through the haze: evaluating the CALIPSO level 2 aerosol optical depth using airborne high spectral resolution lidar data

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument onboard the Cloud Aerosol Lidar and Pathfinder Satellite Observations (CALIPSO) spacecraft has provided over 8 years of nearly continuous vertical profiling of Earth's atmosphere. In this paper we investigate the CALIOP 532 nm aerosol layer optical depth (AOD) product, the AOD of individual layers, and the column AOD product, the sum AOD of the complete column, using an extensive database of coincident measurements. The CALIOP AOD measurements and AOD uncertainty estimates are compared with collocated AOD measurements collected with the NASA High Spectral Resolution Lidar (HSRL) in the North American and Caribbean regions. In addition, the CALIOP aerosol lidar ratios are investigated using the HSRL measurements. In general, compared with the HSRL values, the CALIOP layer AOD are biased high by less than 50% for AOD < 0.3 with higher errors for higher AOD. Less than 60% of the HSRL AOD measurements are encompassed within the CALIOP layer one-standard-deviation uncertainty range (around the CALIOP layer AOD), so an error estimate is created to encompass 68% of the HSRL data. Using this new metric, the CALIOP layer AOD error is estimated using the HSRL layer AOD as ± 0.035 ± 0.05 · (HSRL layer AOD) at night and ±0.05 ± 0.05 · (HSRL layer AOD) during the daytime. Furthermore, the CALIOP layer AOD error is found to correlate with aerosol loading as well as aerosol subtype, with the AODs in marine and dust layers agreeing most closely with the HSRL values. The lidar ratios used by CALIOP for polluted dust, polluted continental, and biomass burning layers are larger than the values measured by the HSRL in the CALIOP layers, and, therefore, the AODs for these types retrieved by CALIOP were generally too large. We estimated the CALIOP column AOD error can be expressed as ± 0.05 ± 0.07 · (HSRL column AOD) at night and ± 0.08 ± 0.1 · (HSRL column AOD) during the daytime. Multiple sources of

  18. Looking through the haze: evaluating the CALIPSO level 2 aerosol optical depth using airborne high spectral resolution lidar data

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument onboard the Cloud-Aerosol Lidar and Pathfinder Satellite Observations (CALIPSO) spacecraft has provided over 8 yr of nearly continuous vertical profiling of Earth's atmosphere. In this paper we investigate the V3.01 and V3.02 CALIOP 532 nm aerosol layer optical depth (AOD) product (i.e the AOD of individual layers) and the column AOD product (i.e., the sum AOD of the complete column) using an extensive database of coincident measurements. The CALIOP AOD measurements and AOD uncertainty estimates are compared with collocated AOD measurements collected with the NASA High Spectral Resolution Lidar (HSRL) in the North American and Caribbean regions. In addition, the CALIOP aerosol lidar ratios are investigated using the HSRL measurements. In general, compared with the HSRL values, the CALIOP layer AOD are biased high by less than 50% for AOD < 0.3 with higher errors for higher AOD. Less than 60% of the HSRL AOD measurements are encompassed within the CALIOP layer 1 SD uncertainty range (around the CALIOP layer AOD), so an error estimate is created to encompass 68% of the HSRL data. Using this new metric, the CALIOP layer AOD error is estimated using the HSRL layer AOD as ±0.035 ± 0.05 · (HSRL layer AOD) at night and ±0.05 ± 0.05 · (HSRL layer AOD) during the daytime. Furthermore, the CALIOP layer AOD error is found to correlate with aerosol loading as well as aerosol subtype, with the AODs in marine and dust layers agreeing most closely with the HSRL values. The lidar ratios used by CALIOP for polluted dust, polluted continental, and biomass burning layers are larger than the values measured by the HSRL in the CALIOP layers, and therefore the AODs for these types retrieved by CALIOP were generally too large. We estimated the CALIOP column AOD error can be expressed as ±0.05 ± 0.07 · (HSRL column AOD) at night and ±0.08 ± 0.1 · (HSRL column AOD) during the daytime. Multiple sources of

  19. An approach for combining airborne LiDAR and high-resolution aerial color imagery using Gaussian processes

    NASA Astrophysics Data System (ADS)

    Liu, Yansong; Monteiro, Sildomar T.; Saber, Eli

    2015-10-01

    Changes in vegetation cover, building construction, road network and traffic conditions caused by urban expansion affect the human habitat as well as the natural environment in rapidly developing cities. It is crucial to assess these changes and respond accordingly by identifying man-made and natural structures with accurate classification algorithms. With the increase in use of multi-sensor remote sensing systems, researchers are able to obtain a more complete description of the scene of interest. By utilizing multi-sensor data, the accuracy of classification algorithms can be improved. In this paper, we propose a method for combining 3D LiDAR point clouds and high-resolution color images to classify urban areas using Gaussian processes (GP). GP classification is a powerful non-parametric classification method that yields probabilistic classification results. It makes predictions in a way that addresses the uncertainty of real world. In this paper, we attempt to identify man-made and natural objects in urban areas including buildings, roads, trees, grass, water and vehicles. LiDAR features are derived from the 3D point clouds and the spatial and color features are extracted from RGB images. For classification, we use the Laplacian approximation for GP binary classification on the new combined feature space. The multiclass classification has been implemented by using one-vs-all binary classification strategy. The result of applying support vector machines (SVMs) and logistic regression (LR) classifier is also provided for comparison. Our experiments show a clear improvement of classification results by using the two sensors combined instead of each sensor separately. Also we found the advantage of applying GP approach to handle the uncertainty in classification result without compromising accuracy compared to SVM, which is considered as the state-of-the-art classification method.

  20. Highly sensitive electronic whiskers based on patterned carbon nanotube and silver nanoparticle composite films.

    PubMed

    Takei, Kuniharu; Yu, Zhibin; Zheng, Maxwell; Ota, Hiroki; Takahashi, Toshitake; Javey, Ali

    2014-02-01

    Mammalian whiskers present an important class of tactile sensors that complement the functionalities of skin for detecting wind with high sensitivity and navigation around local obstacles. Here, we report electronic whiskers based on highly tunable composite films of carbon nanotubes and silver nanoparticles that are patterned on high-aspect-ratio elastic fibers. The nanotubes form a conductive network matrix with excellent bendability, and nanoparticle loading enhances the conductivity and endows the composite with high strain sensitivity. The resistivity of the composites is highly sensitive to strain with a pressure sensitivity of up to ∼8%/Pa for the whiskers, which is >10× higher than all previously reported capacitive or resistive pressure sensors. It is notable that the resistivity and sensitivity of the composite films can be readily modulated by a few orders of magnitude by changing the composition ratio of the components, thereby allowing for exploration of whisker sensors with excellent performance. Systems consisting of whisker arrays are fabricated, and as a proof of concept, real-time two- and three-dimensional gas-flow mapping is demonstrated. The ultrahigh sensitivity and ease of fabrication of the demonstrated whiskers may enable a wide range of applications in advanced robotics and human-machine interfacing. PMID:24449857

  1. Interpersonal sensitivity and functioning impairment in youth at ultra-high risk for psychosis.

    PubMed

    Masillo, A; Valmaggia, L R; Saba, R; Brandizzi, M; Lindau, J F; Solfanelli, A; Curto, M; Narilli, F; Telesforo, L; Kotzalidis, G D; Di Pietro, D; D'Alema, M; Girardi, P; Fiori Nastro, P

    2016-01-01

    A personality trait that often elicits poor and uneasy interpersonal relationships is interpersonal sensitivity. The aim of the present study was to explore the relationship between interpersonal sensitivity and psychosocial functioning in individuals at ultra-high risk for psychosis as compared to help-seeking individuals who screened negative for an ultra-high risk of psychosis. A total sample of 147 adolescents and young adult who were help seeking for emerging mental health problems participated in the study. The sample was divided into two groups: 39 individuals who met criteria for an ultra-high-risk mental state (UHR), and 108 (NS). The whole sample completed the Interpersonal Sensitivity Measure (IPSM) and the Global Functioning: Social and Role Scale (GF:SS; GF:RS). Mediation analysis was used to explore whether attenuated negative symptoms mediated the relationship between interpersonal sensitivity and social functioning. Individuals with UHR state showed higher IPSM scores and lower GF:SS and GF:RS scores than NS participants. A statistically negative significant correlation between two IPSM subscales (Interpersonal Awareness and Timidity) and GF:SS was found in both groups. Our results also suggest that the relationship between the aforementioned aspects of interpersonal sensitivity and social functioning was not mediated by negative prodromal symptoms. This study suggests that some aspects of interpersonal sensitivity were associated with low level of social functioning. Assessing and treating interpersonal sensitivity may be a promising therapeutic target to improve social functioning in young help-seeking individuals.

  2. Variable sensitivity of US maize yield to high temperatures across developmental stages

    NASA Astrophysics Data System (ADS)

    Butler, E. E.; Huybers, P. J.

    2013-12-01

    The sensitivity of maize to high temperatures has been widely demonstrated. Furthermore, field work has indicated that reproductive development stages are particularly sensitive to stress, but this relationship has not been quantified across a wide geographic region. Here, the relationship between maize yield and temperature variations is examined as a function of developmental stage. US state-level data from the National Agriculture Statistics Service provide dates for six growing stages: planting, silking, doughing, dented, mature, and harvested. Temperatures that correspond to each developmental stage are then inferred from a network of weather station observations interpolated to the county level, and a multiple linear regression technique is employed to estimate the sensitivity of county yield outcomes to variations in growing-degree days and an analogous measure of high temperatures referred to as killing-degree days. Uncertainties in the transition times between county-level growth stages are accounted for. Results indicate that the silking and dented stages are generally the most sensitive to killing degree days, with silking the most sensitive stage in the US South and dented the most sensitive in the US North. These variable patterns of sensitivity aid in interpreting which weather events are of greatest significance to maize yields and provide some insight into how shifts in planting time or changes in developmental timing would influence the risks associated with exposure to high temperatures.

  3. Photoreactivation in Airborne Mycobacterium parafortuitum

    PubMed Central

    Peccia, Jordan; Hernandez, Mark

    2001-01-01

    Photoreactivation was observed in airborne Mycobacterium parafortuitum exposed concurrently to UV radiation (254 nm) and visible light. Photoreactivation rates of airborne cells increased with increasing relative humidity (RH) and decreased with increasing UV dose. Under a constant UV dose with visible light absent, the UV inactivation rate of airborne M. parafortuitum cells decreased by a factor of 4 as RH increased from 40 to 95%; however, under identical conditions with visible light present, the UV inactivation rate of airborne cells decreased only by a factor of 2. When irradiated in the absence of visible light, cellular cyclobutane thymine dimer content of UV-irradiated airborne M. parafortuitum and Serratia marcescens increased in response to RH increases. Results suggest that, unlike in waterborne bacteria, cyclobutane thymine dimers are not the most significant form of UV-induced DNA damage incurred by airborne bacteria and that the distribution of DNA photoproducts incorporated into UV-irradiated airborne cells is a function of RH. PMID:11526027

  4. Highly Sensitive Electrochemical Determination of Alfatoxin B1 Using Quantum Dots-Assembled Amplification Labels

    PubMed Central

    Zeng, Xiaoqun; Gao, Huiju; Pan, Daodong; Sun, Yangying; Cao, Jinxuan; Wu, Zhen; Pan, Zhenyu

    2015-01-01

    A competitive electrochemical immunoassay for highly sensitive detection of AFB1 is demonstrated using layer-by-layer (LBL) assembled quantum dots (QDs) as labels. To investigate the effects of the higher sensitivity of square wave voltammetric stripping (SWV) and of the LBL technique on the proposed immunoassays, the proposed assay was compared to electrochemical (EC) and fluorescent immunoassays, which did not use LBL technology. Peanut samples were analyzed using the three immunoassays. The limits of detection (LODs) were 0.018, 0.046 and 0.212 ng/mL, respectively, while the sensitivities were 0.308, 1.011 and 4.594 ng/mL, respectively. The proposed electrochemical immunoassay displayed a significant improvement in sensitivity, thereby providing a simple and sensitive alternative strategy for determining AFB1 levels in peanut samples. PMID:26307990

  5. Highly sensitive and reconfigurable fiber optic current sensor by optical recirculating in a fiber loop.

    PubMed

    Du, Jiangbing; Tao, Yemeng; Liu, Yinping; Ma, Lin; Zhang, Wenjia; He, Zuyuan

    2016-08-01

    An advanced fiber optic current sensor (FOCS) is proposed based on recirculating fiber loop architecture for significantly enhancing the current sensitivity. The recirculating loop is constructed by a 2X2 optical switch and the standard single mode fiber (SSMF) is used as the sensing head. The proposed FOCS is coupler-free with low insertion loss which results in a significantly improved current sensitivity. We experimentally obtained a sensitivity of 11.5 degrees/A for 1-Km SSMF FOCS and a sensitivity of 21.2 degrees/A for 500-m SSMF FOCS, both of which have been enhanced by more than ten times. The flexible switch control of recirculating can support the FOCS to work for different current scenarios with the same system and thus reconfigurable operation of the FOCS has been achieved. The significantly enhanced high sensitivity with reconfigurable operation capability makes the proposed FOCS a promising method for practical applications. PMID:27505765

  6. Highly Sensitive Electrochemical Determination of Alfatoxin B1 Using Quantum Dots-Assembled Amplification Labels.

    PubMed

    Zeng, Xiaoqun; Gao, Huiju; Pan, Daodong; Sun, Yangying; Cao, Jinxuan; Wu, Zhen; Pan, Zhenyu

    2015-01-01

    A competitive electrochemical immunoassay for highly sensitive detection of AFB1 is demonstrated using layer-by-layer (LBL) assembled quantum dots (QDs) as labels. To investigate the effects of the higher sensitivity of square wave voltammetric stripping (SWV) and of the LBL technique on the proposed immunoassays, the proposed assay was compared to electrochemical (EC) and fluorescent immunoassays, which did not use LBL technology. Peanut samples were analyzed using the three immunoassays. The limits of detection (LODs) were 0.018, 0.046 and 0.212 ng/mL, respectively, while the sensitivities were 0.308, 1.011 and 4.594 ng/mL, respectively. The proposed electrochemical immunoassay displayed a significant improvement in sensitivity, thereby providing a simple and sensitive alternative strategy for determining AFB1 levels in peanut samples. PMID:26307990

  7. Highly Sensitive Electrochemical Determination of Alfatoxin B1 Using Quantum Dots-Assembled Amplification Labels.

    PubMed

    Zeng, Xiaoqun; Gao, Huiju; Pan, Daodong; Sun, Yangying; Cao, Jinxuan; Wu, Zhen; Pan, Zhenyu

    2015-08-20

    A competitive electrochemical immunoassay for highly sensitive detection of AFB1 is demonstrated using layer-by-layer (LBL) assembled quantum dots (QDs) as labels. To investigate the effects of the higher sensitivity of square wave voltammetric stripping (SWV) and of the LBL technique on the proposed immunoassays, the proposed assay was compared to electrochemical (EC) and fluorescent immunoassays, which did not use LBL technology. Peanut samples were analyzed using the three immunoassays. The limits of detection (LODs) were 0.018, 0.046 and 0.212 ng/mL, respectively, while the sensitivities were 0.308, 1.011 and 4.594 ng/mL, respectively. The proposed electrochemical immunoassay displayed a significant improvement in sensitivity, thereby providing a simple and sensitive alternative strategy for determining AFB1 levels in peanut samples.

  8. Structure-function analysis identifies highly sensitive strigolactone receptors in Striga.

    PubMed

    Toh, Shigeo; Holbrook-Smith, Duncan; Stogios, Peter J; Onopriyenko, Olena; Lumba, Shelley; Tsuchiya, Yuichiro; Savchenko, Alexei; McCourt, Peter

    2015-10-01

    Strigolactones are naturally occurring signaling molecules that affect plant development, fungi-plant interactions, and parasitic plant infestations. We characterized the function of 11 strigolactone receptors from the parasitic plant Striga hermonthica using chemical and structural biology. We found a clade of polyspecific receptors, including one that is sensitive to picomolar concentrations of strigolactone. A crystal structure of a highly sensitive strigolactone receptor from Striga revealed a larger binding pocket than that of the Arabidopsis receptor, which could explain the increased range of strigolactone sensitivity. Thus, the sensitivity of Striga to strigolactones from host plants is driven by receptor sensitivity. By expressing strigolactone receptors in Arabidopsis, we developed a bioassay that can be used to identify chemicals and crops with altered strigolactone levels. PMID:26450211

  9. Urban greenness influences airborne bacterial community composition.

    PubMed

    Mhuireach, Gwynne; Johnson, Bart R; Altrichter, Adam E; Ladau, Joshua; Meadow, James F; Pollard, Katherine S; Green, Jessica L

    2016-11-15

    Urban green space provides health benefits for city dwellers, and new evidence suggests that microorganisms associated with soil and vegetation could play a role. While airborne microorganisms are ubiquitous in urban areas, the influence of nearby vegetation on airborne microbial communities remains poorly understood. We examined airborne microbial communities in parks and parking lots in Eugene, Oregon, using high-throughput sequencing of the bacterial 16S rRNA gene on the Illumina MiSeq platform to identify bacterial taxa, and GIS to measure vegetation cover in buffer zones of different diameters. Our goal was to explore variation among highly vegetated (parks) versus non-vegetated (parking lots) urban environments. A secondary objective was to evaluate passive versus active collection methods for outdoor airborne microbial sampling. Airborne bacterial communities from five parks were different from those of five parking lots (p=0.023), although alpha diversity was similar. Direct gradient analysis showed that the proportion of vegetated area within a 50m radius of the sampling station explained 15% of the variation in bacterial community composition. A number of key taxa, including several Acidobacteriaceae were substantially more abundant in parks, while parking lots had higher relative abundance of Acetobacteraceae. Parks had greater beta diversity than parking lots, i.e. individual parks were characterized by unique bacterial signatures, whereas parking lot communities tended to be similar to each other. Although parks and parking lots were selected to form pairs of nearby sites, spatial proximity did not appear to affect compositional similarity. Our results also showed that passive and active collection methods gave comparable results, indicating the "settling dish" method is effective for outdoor airborne sampling. This work sets a foundation for understanding how urban vegetation may impact microbial communities, with potential implications for designing

  10. Urban greenness influences airborne bacterial community composition.

    PubMed

    Mhuireach, Gwynne; Johnson, Bart R; Altrichter, Adam E; Ladau, Joshua; Meadow, James F; Pollard, Katherine S; Green, Jessica L

    2016-11-15

    Urban green space provides health benefits for city dwellers, and new evidence suggests that microorganisms associated with soil and vegetation could play a role. While airborne microorganisms are ubiquitous in urban areas, the influence of nearby vegetation on airborne microbial communities remains poorly understood. We examined airborne microbial communities in parks and parking lots in Eugene, Oregon, using high-throughput sequencing of the bacterial 16S rRNA gene on the Illumina MiSeq platform to identify bacterial taxa, and GIS to measure vegetation cover in buffer zones of different diameters. Our goal was to explore variation among highly vegetated (parks) versus non-vegetated (parking lots) urban environments. A secondary objective was to evaluate passive versus active collection methods for outdoor airborne microbial sampling. Airborne bacterial communities from five parks were different from those of five parking lots (p=0.023), although alpha diversity was similar. Direct gradient analysis showed that the proportion of vegetated area within a 50m radius of the sampling station explained 15% of the variation in bacterial community composition. A number of key taxa, including several Acidobacteriaceae were substantially more abundant in parks, while parking lots had higher relative abundance of Acetobacteraceae. Parks had greater beta diversity than parking lots, i.e. individual parks were characterized by unique bacterial signatures, whereas parking lot communities tended to be similar to each other. Although parks and parking lots were selected to form pairs of nearby sites, spatial proximity did not appear to affect compositional similarity. Our results also showed that passive and active collection methods gave comparable results, indicating the "settling dish" method is effective for outdoor airborne sampling. This work sets a foundation for understanding how urban vegetation may impact microbial communities, with potential implications for designing

  11. Proposed helmet PET geometries with add-on detectors for high sensitivity brain imaging

    NASA Astrophysics Data System (ADS)

    Tashima, Hideaki; Yamaya, Taiga

    2016-10-01

    For dedicated brain PET, we can significantly improve sensitivity for the cerebrum region by arranging detectors in a compact hemisphere. The geometrical sensitivity for the top region of the hemisphere is increased compared with conventional cylindrical PET consisting of the same number of detectors. However, the geometrical sensitivity at the center region of the hemisphere is still low because the bottom edge of the field-of-view is open, the same as for the cylindrical PET. In this paper, we proposed a helmet PET with add-on detectors for high sensitivity brain PET imaging for both center and top regions. The key point is the add-on detectors covering some portion of the spherical surface in addition to the hemisphere. As the location of the add-on detectors, we proposed three choices: a chin detector, ear detectors, and a neck detector. For example, the geometrical sensitivity for the region-of-interest at the center was increased by 200% by adding the chin detector which increased the size by 12% of the size of the hemisphere detector. The other add-on detectors gave almost the same increased sensitivity effect as the chin detector did. Compared with standard whole-body-cylindrical PET, the proposed geometries can achieve 2.6 times higher sensitivity for brain region even with less than 1/4 detectors. In addition, we conducted imaging simulations for geometries with a diameter of 250 mm and with high resolution depth-of-interaction detectors. The simulation results showed that the proposed geometries increased image quality, and all of the add-on detectors were equivalently effective. In conclusion, the proposed geometries have high potential for widespread applications in high-sensitivity, high-resolution, and low-cost brain PET imaging.

  12. Towards high-sensitivity and high-resolution submillimeter-wave video imaging

    NASA Astrophysics Data System (ADS)

    Heinz, Erik; May, Torsten; Born, Detlef; Zieger, Gabriel; Anders, Solveig; Zakosarenko, Viatcheslav; Schubert, Marco; Krause, Torsten; Krüger, André; Schulz, Marco; Meyer, Hans-Georg

    2011-05-01

    Against a background of newly emerged security threats the well-established idea of utilizing submillimeter-wave radiation for personal security screening applications has recently evolved into a promising technology. Possible application scenarios demand sensitive, fast, flexible and high-quality imaging techniques. At present, best results are obtained by passive imaging using cryogenic microbolometers as radiation detectors. Building upon the concept of a passive submillimeter-wave stand-off video camera introduced previously, we present the evolution of this concept in a practical application-ready imaging device. This has been achieved using a variety of measures such as optimizing the detector parameters, improving the scanning mechanism, increasing the sampling speed, and enhancing the camera software. The image generation algorithm has been improved and an automatic sensor calibration technique has been implemented taking advantage of redundancy in the sensor data. The concept is based on a Cassegrain-type mirror optics, an opto-mechanical scanner providing spiraliform scanning traces, and an array of 20 superconducting transition-edge sensors (TES) operated at a temperature of 450-650 mK. The TES are cooled by a closed-cycle cooling system and read out by superconducting quantum interference devices (SQUIDs). The frequency band of operation centers around 350 GHz. The camera can operate at an object distance of 7-10 m. At 9m distance it covers a field of view of 110 cm diameter, achieves a spatial resolution of 2 cm and a pixel NETD (noise equivalent temperature difference) of 0.1-0.4 K. The maximum frame rate is 10 frames per second.

  13. Is sensitivity to reward associated with the malleability of implicit inclinations toward high-fat food?

    PubMed

    Ashby, Casey R; Stritzke, Werner G K

    2013-08-01

    Two experiments examined the effect of positive and negative priming on implicit approach and avoidance inclinations toward high-fat food stimuli in participants high or low in reward sensitivity, using personalized unipolar variants of the Implicit Association Test (IAT; A. G. Greenwald, D. E. McGhee, & J. L. K. Schwartz, 1998, "Measuring individual differences in implicit cognition: The Implicit Association Test," Journal of Personality and Social Psychology, Vol. 74, pp. 1464-1480). Participants high in reward sensitivity showed an automatic processing bias that is characterized by a dual vulnerability of being particularly susceptible to priming of the rewarding aspects of high-fat foods, while being unaffected by priming of the negative aspects of those foods. In contrast, participants low in reward sensitivity generally showed no facilitation of implicit-approach inclinations following positive priming, but consistently showed facilitation of implicit-avoidance inclinations following negative priming. These results are consistent with the revised reinforcement sensitivity theory ( J. A. Gray & N. McNaughton, 2000, The neuropsychology of anxiety: An enquiry into the functions of the septo-hippocampal system, 2nd ed., New York, NY, Oxford University Press.) and suggest that the systems mediating reward sensitivity and punishment sensitivity are not orthogonal, as predicted by the separable subsystems hypothesis, but can be interdependent, as predicted by the joint subsystems hypothesis.

  14. Is sensitivity to reward associated with the malleability of implicit inclinations toward high-fat food?

    PubMed

    Ashby, Casey R; Stritzke, Werner G K

    2013-08-01

    Two experiments examined the effect of positive and negative priming on implicit approach and avoidance inclinations toward high-fat food stimuli in participants high or low in reward sensitivity, using personalized unipolar variants of the Implicit Association Test (IAT; A. G. Greenwald, D. E. McGhee, & J. L. K. Schwartz, 1998, "Measuring individual differences in implicit cognition: The Implicit Association Test," Journal of Personality and Social Psychology, Vol. 74, pp. 1464-1480). Participants high in reward sensitivity showed an automatic processing bias that is characterized by a dual vulnerability of being particularly susceptible to priming of the rewarding aspects of high-fat foods, while being unaffected by priming of the negative aspects of those foods. In contrast, participants low in reward sensitivity generally showed no facilitation of implicit-approach inclinations following positive priming, but consistently showed facilitation of implicit-avoidance inclinations following negative priming. These results are consistent with the revised reinforcement sensitivity theory ( J. A. Gray & N. McNaughton, 2000, The neuropsychology of anxiety: An enquiry into the functions of the septo-hippocampal system, 2nd ed., New York, NY, Oxford University Press.) and suggest that the systems mediating reward sensitivity and punishment sensitivity are not orthogonal, as predicted by the separable subsystems hypothesis, but can be interdependent, as predicted by the joint subsystems hypothesis. PMID:23527505

  15. Longevity Tests of High-Sensitivity BD-PND Bubble Dosimeters

    SciTech Connect

    Radev, R; Carlberg, E

    2002-07-09

    Medium- and very-high-sensitivity neutron bubble dosimeters (BD-PNDs) made by Bubble Technology Industries (BTI) were used to study the life span of such dosimeters in a standard setup with a {sup 252}Cf source. Although data on the longevity of bubble dosimeters with low and medium sensitivity exist, such data for dosimeters with high and very high sensitivity are not readily available. The manufacturer guarantees optimum dosimeter performance for 3 months after receipt. However, it is important to know the change in the dosimeters' characteristics with time, especially after the first 3 months. The long-term performance of four sets of very high sensitivity and one set of medium-sensitivity bubble dosimeters was examined for periods of up to 13 months. During that time, the detectors were exposed and reset more than 20 times. Although departures from initial detection sensitivity were observed in several cases, the detectors indicated a significantly longer life span than stated in the manufacturer's warranty. In addition, the change in the number of bubbles and in evaluated neutron dose as a function of the time from the end of exposure until the dosimeters were read was investigated.

  16. Green laser excited surface plasmon resonance biosensor utilizing highly sensitive phase interrogation detection

    NASA Astrophysics Data System (ADS)

    Chen, How-Foo; Hsu, Wei-Chen; Wang, Ya-Jung; Yen, Ta-Jen

    2010-04-01

    Surface plasmon resonance (SPR) biosensors have been widely used for dynamical analysis of molecular affinity, bacterium screening, and drug discovery due to its advantages of label-free detection, dynamic interaction analysis, small sample volume, and ultra sensitivity (feasibility of single molecular detection). Recently, SPR biosensing for cell imaging known as SPR microscopy (SPRM) has attracted great attention due to the characteristics of SPR biosensors. However, it is well known that the trends of sensitivity and spatial resolution are opposite to each other: Surface plasmon waves (SPWs) with shorter wavelength which provides higher spatial resolution has less sensitivity. It is known that the spatial resolution of SPRM is limited by the propagation length of surface plasmon wave (SPW) along the metaldielectric interface. SPW excited by 632.8 nm light has the propagation length of 3 um. This length becomes longer when a longer wavelength is selected. While most of SPR biosensors are built with 632.8 nm or longer wavelength for high sensitivity, using 532nm light to excite SPWs is desired for submicron resolution since the propagation length is around 150 nm. Different from current phase interrogation methods, the proposed phase interrogation method is highly sensitive and suitable for CCD imaging. Although it is generally believed that SPWs with wavelength 532nm has poor sensitivity, the experimental result showed that the setup can reach the sensitivity lower than 2×10-6 RIU when sucrose is used as the test sample.

  17. Highly sensitive detection of dipicolinic acid with a water-dispersible terbium-metal organic framework.

    PubMed

    Bhardwaj, Neha; Bhardwaj, Sanjeev; Mehta, Jyotsana; Kim, Ki-Hyun; Deep, Akash

    2016-12-15

    The sensitive detection of dipicolinic acid (DPA) is strongly associated with the sensing of bacterial organisms in food and many types of environmental samples. To date, the demand for a sensitive detection method for bacterial toxicity has increased remarkably. Herein, we investigated the DPA detection potential of a water-dispersible terbium-metal organic framework (Tb-MOF) based on the fluorescence quenching mechanism. The Tb-MOF showed a highly sensitive ability to detect DPA at a limit of detection of 0.04nM (linear range of detection: 1nM to 5µM) and also offered enhanced selectivity from other commonly associated organic molecules. The present study provides a basis for the application of Tb-MOF for direct, convenient, highly sensitive, and specific detection of DPA in the actual samples.

  18. Highly sensitive detection of dipicolinic acid with a water-dispersible terbium-metal organic framework.

    PubMed

    Bhardwaj, Neha; Bhardwaj, Sanjeev; Mehta, Jyotsana; Kim, Ki-Hyun; Deep, Akash

    2016-12-15

    The sensitive detection of dipicolinic acid (DPA) is strongly associated with the sensing of bacterial organisms in food and many types of environmental samples. To date, the demand for a sensitive detection method for bacterial toxicity has increased remarkably. Herein, we investigated the DPA detection potential of a water-dispersible terbium-metal organic framework (Tb-MOF) based on the fluorescence quenching mechanism. The Tb-MOF showed a highly sensitive ability to detect DPA at a limit of detection of 0.04nM (linear range of detection: 1nM to 5µM) and also offered enhanced selectivity from other commonly associated organic molecules. The present study provides a basis for the application of Tb-MOF for direct, convenient, highly sensitive, and specific detection of DPA in the actual samples. PMID:27479046

  19. Highly sensitive digoxigenin-labelled DNA probe for the detection of potato spindle tuber viroid.

    PubMed

    Welnicki, M; Hiruki, C

    1992-09-01

    A molecular probe pSPAv6.2(+), with concatameric insert representing 6.2-times repeated copy of potato spindle tuber viroid (PSTV) RNA, was labelled with digoxigenin and used to detect PSTV by dot-blot hybridization assay. The probe was highly sensitive and specific, detecting as little as 2.5 pg of PSTV RNA. Both severe and mild PSTV strains were detectable in 64-512-times diluted crude extracts from infected tomato leaves, and potato leaves, sprouts, and seeds. For extraction of plant tissue three buffers were compared to determine the lowest non-specific background and the highest sensitivity. The results showed that the digoxigenin-labelled probe is as sensitive as the 32P-labelled probe and can replace radioactive techniques in PSTV detection. With such high sensitivity, the probe is also potentially useful for detecting the viroid in composite samples of mass-indexing programs.

  20. Polycrystalline CVD diamond detector: Fast response and high sensitivity with large area

    SciTech Connect

    Liu, Linyue Zhang, Xianpeng; Zhong, Yunhong; Ouyang, Xiaoping Zhang, Jianfu

    2014-01-15

    Polycrystalline diamond was successfully used to fabricate a large area (diameter up to 46 mm) radiation detector. It was proven that the developed detector shows a fast pulsed response time and a high sensitivity, therefore its rise time is lower than 5 ns, which is two times faster than that of a Si-PIN detector of the same size. And because of the large sensitive area, this detector shows good dominance in fast pulsed and low density radiation detection.