Science.gov

Sample records for emitted airborne noise

  1. Analysis of noise emitted from diesel engines

    NASA Astrophysics Data System (ADS)

    Narayan, S.

    2015-12-01

    In this work combustion noise produced in diesel engines has been investigated. In order to reduce the exhaust emissions various injection parameters need to be studied and optimized. The noise has been investigated by mean of data obtained from cylinder pressure measurements using piezo electric transducers and microphones on a dual cylinder diesel engine test rig. The engine was run under various operating conditions varying various injection parameters to investigate the effects of noise emissions under various testing conditions.

  2. Prediction and removal of rotation noise in airborne EM systems

    NASA Astrophysics Data System (ADS)

    Kratzer, Terence 12Macnae, James

    2014-03-01

    We aim to eliminate or reduce significant impediments to conductive target detection and conductive cover penetration in airborne electromagnetic (AEM) systems. Existing limitations come from the very high noise encountered at low base frequencies, caused by rotations of vector magnetic field sensors in the Earth's magnetic field. We use the output of tri-axial rotation-rate sensors to predict and subtract the rotation noise from rigidly coupled ARMIT magnetic field sensors. The approach is successful in reducing rotation noise by one to two orders of magnitude at low frequencies.

  3. Interaction of airborne and structureborne noise radiated by plates. Volume 2: Experimental study

    NASA Technical Reports Server (NTRS)

    Mcgary, M. C.

    1986-01-01

    The interaction of airborne and structureborne noise radiated by aircaraft materials was studied. The results corroborate the findings of an earlier analytical study by showing that the noise radiation of vibrating plates due to combined airborne and structureborne inputs possesses a stong synergistic nature. The large influence of the interaction between the airborne and structureborne inputs was hitherto ignored by researchers of aircraft interior noise problems.

  4. New specific indicators for qPCR monitoring of airborne microorganisms emitted by composting plants

    NASA Astrophysics Data System (ADS)

    Le Goff, Olivier; Godon, Jean-Jacques; Steyer, Jean-Philippe; Wéry, Nathalie

    2011-09-01

    Bioaerosols emitted from composting plants are an issue because of their potential harmful impact on public or workers' health. There is a major lack of knowledge concerning the dispersal of airborne microorganisms emitted by composting plants and the consequent potential exposure of nearby residents. This inadequate knowledge is partly due to the fact that there is currently no method for specifically tracing these microorganisms in the air. The objective of this study was to validate the use of microbial groups as indicators of composting bioaerosols by comparing their concentration in air samples, whether impacted by composting activity or not. Three potential microbial indicators were chosen among the core species of composting bioaerosols. They belong to the genus Saccharopolyspora, to the Thermoactinomycetaceae and to the fungus Thermomyces. Quantitative PCR systems using TaqMan probes were designed to quantify each of the three phylotypes in air samples collected outdoors in natural environments and at composting plants. Compost-turning operations at industrial plants resulted in an increase in the concentration of the three phylotypes of at least 2 orders of magnitude when compared to the concentration measured in control samples collected upwind, and of at least 1 order of magnitude compared to the background concentration measured in natural environments unaffected by industrial activity. In conclusion, these three thermophilic phylotypes can be used as indicators of airborne microorganisms emitted by industrial composting plants. They may be particularly relevant in studying the dispersal of bioaerosols around composting plants and the exposure of nearby residents. This is the first time that indicators of compost bioaerosols have been validated by comparing their concentrations in impacted samples to their background levels in natural environments.

  5. On-site application of air cleaner emitting plasma ion to reduce airborne contaminants in pig building

    NASA Astrophysics Data System (ADS)

    Cho, Man Su; Ko, Han Jong; Kim, Daekeun; Kim, Ki Youn

    2012-12-01

    The objective of this field study is to evaluate temporal reduction efficiency of air cleaner emitting plasma ion on airborne pollutants emitted from pig building. The operation principle of air cleaner based on plasma ion is that hydrogen atoms and oxygen ions combine to form hydroperoxyl radicals (HOO-), which surround and attach to surface of airborne microorganisms and eliminate them by breaking the hydrogen bond in their protein structure. In gaseous pollutants, it was found that there is no reduction effect of the air cleaner on ammonia and hydrogen sulfide (p > 0.05). In particulate pollutants, the air cleaner showed mean 79%(±6.1) and 78%(±3.0) of reduction efficiency for PM2.5. and PM1, respectively, compared to the control without air cleaner (p < 0.05). However, there is no significant difference in TSP and PM10 between the treatment with air cleaner and the control without air cleaner (p > 0.05). In biological pollutants, the mean reduction efficiencies for airborne bacteria and fungi by application of air cleaner were 22%(±6.6) and 25%(±8.7), respectively (p < 0.05). Based on the results obtained from this study, it was concluded that the air cleaner had a positive reduction effect on PM2.5, PM1, airborne bacteria and airborne fungi among airborne pollutants distributed in pig building while it did not lead to significant reduction of ammonia and hydrogen sulfide.

  6. A Preliminary Investigation of Systematic Noise in Data Acquired with the Airborne Imaging Spectrometer

    NASA Technical Reports Server (NTRS)

    Masuoka, E.

    1985-01-01

    Systematic noise is present in Airborne Imaging Spectrometer (AIS) data collected on October 26, 1983 and May 5, 1984 in grating position 0 (1.2 to 1.5 microns). In the October data set the noise occurs as 135 scan lines of low DN's every 270 scan lines. The noise is particularly bad in bands nine through thirty, restricting effective analysis to at best ten of the 32 bands. In the May data the regions of severe noise have been eliminated, but systematic noise is present with three frequencies (3, 106 and 200 scan lines) in all thirty two bands. The periodic nature of the noise in both data sets suggests that it could be removed as part of routine processing. This is necessary before classification routines or statistical analyses are used with these data.

  7. A comparison of the structureborne and airborne paths for propfan interior noise

    NASA Technical Reports Server (NTRS)

    Eversman, W.; Koval, L. R.; Ramakrishnan, J. V.

    1986-01-01

    A comparison is made between the relative levels of aircraft interior noise related to structureborne and airborne paths for the same propeller source. A simple, but physically meaningful, model of the structure treats the fuselage interior as a rectangular cavity with five rigid walls. The sixth wall, the fuselage sidewall, is a stiffened panel. The wing is modeled as a simple beam carried into the fuselage by a large discrete stiffener representing the carry-through structure. The fuselage interior is represented by analytically-derived acoustic cavity modes and the entire structure is represented by structural modes derived from a finite element model. The noise source for structureborne noise is the unsteady lift generation on the wing due to the rotating trailing vortex system of the propeller. The airborne noise source is the acoustic field created by a propeller model consistent with the vortex representation. Comparisons are made on the basis of interior noise over a range of propeller rotational frequencies at a fixed thrust.

  8. Interaction of airborne and structureborne noise radiated by plates. Volume 1: Analytical study

    NASA Technical Reports Server (NTRS)

    Mcgary, M. C.

    1986-01-01

    The interaction of airborne and structureborne noise radiated by aircraft materials was examined. The theory and results of several computer simulations of the noise radiated by thin, isotropic, rectangular aluminum plates due to fully coherent combined acoustic and vibrational inputs is presented. The most significant finding was the extremely large influence that the relative phase between inputs has on the combined noise radiation of the plates. Phase dependent effects manifest themselves as cross terms in both the dynamic and acoustic portions of the analysis. Computer simulations show that these cross terms can radically alter the combined sound power radiated by plates constructed of aircraft-type materials. The results suggest that airborne-structureborne interactive effects could be responsible for a significant portion of the overall noise radiated by aircraft-type structures in the low frequency regime. This implies that previous analytical and experimental studies may have neglected an important physical phenomenon in the analayses of the interior noise of propeller dirven aircraft.

  9. Magnetic field enhancement of generation-recombination and shot noise in organic light emitting diodes

    SciTech Connect

    Djidjou, T. K.; Basel, Tek; Rogachev, A.; Chen, Ying; Shinar, J.

    2015-03-21

    We have studied the effect of magnetic field on noise in series of 2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene-based organic light emitting diodes with dominant hole injection, dominant electron injection, and balanced electron and hole injection. The noise spectra of the balanced devices revealed the generation-recombination (g-r) noise term, which we associated with bimolecular electron-hole recombination. The presence of the g-r noise term is correlated with the strong organic magnetoresistance (up to 25%) observed in the balanced devices. The noise spectra also have the shot noise contribution with the Fano factor 0.25–0.4. We found that time constant of the g-r term decreases and the magnitude of shot noise increases when magnetic field is applied. This behavior can be consistently explained within the polaron-polaron model of organic magnetoresistance. We have not found any evidence that the magnetoresistance in studied devices is affected by traps.

  10. A new measurement method for separating airborne and structureborne noise radiated by aircraft type panels

    NASA Technical Reports Server (NTRS)

    Mcgary, M. C.

    1982-01-01

    The theoretical basis for and experimental validation of a measurement method for separating airborne and structure borne noise radiated by aircraft type panels are presented. An extension of the two microphone, cross spectral, acoustic intensity method combined with existing theory of sound radiation of thin shell structures of various designs, is restricted to the frequency range below the coincidence frequency of the structure. Consequently, the method lends itself to low frequency noise problems such as propeller harmonics. Both an aluminum sheet and two built up aircraft panel designs (two aluminum panels with frames and stringers) with and without added damping were measured. Results indicate that the method is quick, reliable, inexpensive, and can be applied to thin shell structures of various designs.

  11. Noise Whitening in Airborne Wind Profiling With a Pulsed 2-Micron Coherent Doppler Lidar at NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Beyon, Jeffrey Y.; Arthur, Grant E.; Koch, Grady J.; Kavaya, Michael J.

    2012-01-01

    Two different noise whitening methods in airborne wind profiling with a pulsed 2-micron coherent Doppler lidar system at NASA Langley Research Center in Virginia are presented. In order to provide accurate wind parameter estimates from the airborne lidar data acquired during the NASA Genesis and Rapid Intensification Processes (GRIP) campaign in 2010, the adverse effects of background instrument noise must be compensated properly in the early stage of data processing. The results of the two methods are presented using selected GRIP data and compared with the dropsonde data for verification purposes.

  12. Application of Spatial Continuous Wavelet Transforms to Identify Noise in Regional Airborne Electromagnetic Data

    NASA Astrophysics Data System (ADS)

    Nenna, V.; Pidlisecky, A.

    2012-12-01

    As mapping of groundwater resources with airborne electromagnetics expands into more urban areas, it is increasingly important to identify sources of cultural noise in acquired data sets. A number of methods have been proposed to reduce the impact of cultural coupling on acquired data. While intense local calibration to increase the signal to noise ratio has been used, most often in practice, the transients associated with these noise sources are manually identified and filtered out during data processing. This can be a challenging task, particularly as datasets grow large (e.g. up to terabytes of data). In response to this, we propose a method for identifying noise in airborne electromagnetic data based on a spatial application of the continuous wavelet transform (CWT). We apply a continuous wavelet transform to three airborne electromagnetic surveys collected in the Edmonton-Calgary Corridor as part of a groundwater inventory sponsored by the Alberta Geological Survey and Environment Alberta. The three surveys consist of 210 flightlines covering approximately 18 000 linear kilometers with roughly 13 m sounding spacing. B-field and dB/dt data from a three-component 20-channel GeoTEM multicoil system, were recorded at 5 on-time and 15 off-time channels with a total measurement time of 16.664 ms per sounding. The nominal height of vertical axis transmitter was 120 m; the current pulse was 670 A, and the pulse-width was 4.045 ms. Wavelet transforms are localized in time and frequency, similar to a windowed Fourier transform, and are used to identify dominant frequencies within a signal as a function of time or space. While there are a number of options for wavelet functions, we convolve a Morlet wavelet with the data signal at 120 distance scales on a logarithmic scale from 0.1 to 30 km. We calculate the CWT along each flightline for all off-time channels. We then calculate the wavelet power normalized by the data variance, and bin results into 4 bins of spatial

  13. Acoustic confort at home: Noise emitted by house installations. Recommendations in order to avoid such noise

    NASA Astrophysics Data System (ADS)

    Jimenez, Santiago

    2002-11-01

    The present survey consists of the analysis and the study of the solutions used at present in the installations of water supply and elevators. It has been carried out from the acoustic point of view. In order to achieve a thorough study a pilot plant was built in the Laboratory of Acoustics of the School of Industrial Engineering of Terrassa. This pilot plant reproduced different kinds of installations of the water supply in houses. And it has allowed us to systematize the measures and also to determine the optimum solutions from the acoustic perspective. In accordance with the objectives and the process of the survey, the solutions regularly employed in the facilities of water supply and elevators in houses have been analyzed, and levels of noise associated to these facilities have been also presented. A summary of the results obtained in the plant has been included, according to diverse variables. Both the conclusions of the analysis of the data obtained in the laboratory and those of the installations of the houses have been also compared, which has allowed us to describe a series of suggestions with the purpose of reducing the acoustic emission of this type of installations, and increase the acoustic comfort at home. (To be presented in Spanish.)

  14. Probability characteristics of electrical noise in heterojunction light-emitting diodes

    SciTech Connect

    Sergeev, V. A. Frolov, I. V.; Shirokov, A. A.; Shcherbatyuk, Yu. N.

    2011-12-15

    A hardware-software complex for measurements of the characteristics of electrical and optical noise in light-emitting diodes (LEDs) in the frequency range from 1 to 40 kHz is described. The electrical noise of several types of heterojunction-based LEDs are studied; these types include red-emission LEDs with AlInGaP/GaAs quantum wells and the green- and blue-emission LEDs with AlInGaN/SiC quantum wells are studied by the method of discrete samples. The spectra of all studied LEDs in the frequency range from 1 to 10 kHz have the form 1/f{sup {gamma}}. It is noteworthy that, for red-emission LEDs, the exponent {gamma} is significantly smaller than unity; this index is close to unity for the green- and blue-emission LEDs. The characteristic time of correlation of the noise of red-emission LEDs by several times exceeds the correlation times for the blue- and green-emission LEDs. It is shown that reduced functions of the amplitude distribution of the noise voltage are close to Gaussian functions with almost the same dispersion for all LED types.

  15. Evaluating signal-to-noise ratios, loudness, and related measures as indicators of airborne sound insulation.

    PubMed

    Park, H K; Bradley, J S

    2009-09-01

    Subjective ratings of the audibility, annoyance, and loudness of music and speech sounds transmitted through 20 different simulated walls were used to identify better single number ratings of airborne sound insulation. The first part of this research considered standard measures such as the sound transmission class the weighted sound reduction index (R(w)) and variations of these measures [H. K. Park and J. S. Bradley, J. Acoust. Soc. Am. 126, 208-219 (2009)]. This paper considers a number of other measures including signal-to-noise ratios related to the intelligibility of speech and measures related to the loudness of sounds. An exploration of the importance of the included frequencies showed that the optimum ranges of included frequencies were different for speech and music sounds. Measures related to speech intelligibility were useful indicators of responses to speech sounds but were not as successful for music sounds. A-weighted level differences, signal-to-noise ratios and an A-weighted sound transmission loss measure were good predictors of responses when the included frequencies were optimized for each type of sound. The addition of new spectrum adaptation terms to R(w) values were found to be the most practical approach for achieving more accurate predictions of subjective ratings of transmitted speech and music sounds. PMID:19739735

  16. Particle size distribution of airborne Aspergillus fumigatus spores emitted from compost using membrane filtration

    NASA Astrophysics Data System (ADS)

    Deacon, L. J.; Pankhurst, L. J.; Drew, G. H.; Hayes, E. T.; Jackson, S.; Longhurst, P. J.; Longhurst, J. W. S.; Liu, J.; Pollard, S. J. T.; Tyrrel, S. F.

    Information on the particle size distribution of bioaerosols emitted from open air composting operations is valuable in evaluating potential health impacts and is a requirement for improved dispersion simulation modelling. The membrane filter method was used to study the particle size distribution of Aspergillus fumigatus spores in air 50 m downwind of a green waste compost screening operation at a commercial facility. The highest concentrations (approximately 8 × 10 4 CFU m -3) of culturable spores were found on filters with pore diameters in the range 1-2 μm which suggests that the majority of spores are emitted as single cells. The findings were compared to published data collected using an Andersen sampler. Results were significantly correlated ( p < 0.01) indicating that the two methods are directly comparable across all particles sizes for Aspergillus spores.

  17. Characterization and control of airborne particles emitted during production of epoxy/carbon nanotube nanocomposites.

    PubMed

    Cena, Lorenzo G; Peters, Thomas M

    2011-02-01

    This work characterized airborne particles generated from the weighing of bulk, multiwall carbon nanotubes (CNTs) and the manual sanding of epoxy test samples reinforced with CNTs. It also evaluated the effectiveness of three local exhaust ventilation (LEV) conditions (no LEV, custom fume hood, and biosafety cabinet) for control of particles generated during sanding of CNT-epoxy nanocomposites. Particle number and respirable mass concentrations were measured using an optical particle counter (OPC) and a condensation particle counter (CPC), and particle morphology was assessed by transmission electron microscopy. The ratios of the geometric mean (GM) concentrations measured during the process to that measured in the background (P/B ratios) were used as indices of the impact of the process and the LEVs on observed concentrations. Processing CNT-epoxy nanocomposites materials released respirable size airborne particles (P/B ratio: weighing = 1.79; sanding = 5.90) but generally no nanoparticles (P/B ratio ∼1). The particles generated during sanding were predominantly micron sized with protruding CNTs and very different from bulk CNTs that tended to remain in large (>1 μm) tangled clusters. Respirable mass concentrations in the operator's breathing zone were lower when sanding was performed in the biological safety cabinet (GM = 0.20 μg/m(3) compared with those with no LEV (GM = 2.68 μg/m(3) or those when sanding was performed inside the fume hood (GM = 21.4 μg/m(3); p-value < 0.0001). The poor performance of the custom fume hood used in this study may have been exacerbated by its lack of a front sash and rear baffles and its low face velocity (0.39 m/sec). PMID:21253981

  18. A Guide to Airborne, Impact, and Structure Borne Noise--Control in Multifamily Dwellings.

    ERIC Educational Resources Information Center

    Berendt, Raymond D.; And Others

    The control of noise on buildings is discussed extensively in this document, incorporating a broad range of criteria appropriate for isolating air borne, impact, and structure-borne noise associated with residential construction. Subject areas include--(1) noise types, sources, and transmission, (2) general principles of noise control, (3)…

  19. Noise emitted from road, rail and air traffic and their effects on sleep

    NASA Astrophysics Data System (ADS)

    Griefahn, Barbara; Marks, Anke; Robens, Sibylle

    2006-08-01

    This study compared the effects of road, rail, and aircraft noise and tested the applicability of the equivalent noise level for the evaluation of sleep disturbances. Sixteen women and 16 men (19-28 years) slept during 3 consecutive weeks in the laboratory. Eight persons slept in quiet throughout. Twenty-four persons were exposed to road, rail, or aircraft noise with weekly permuted changes. Each week consisted of a random sequence of a quiet night (32 dBA) and 3 nights with equivalent noise levels of 39, 44, and 50 dBA and maximum levels of 50-62, 56-68, and 62-74 dBA, respectively. The polysomnogram was recorded during all nights, sleep quality was assessed and performance tests were completed in the morning. Subjectively evaluated sleep quality decreased and reaction time increased gradually with noise levels, whereas most physiological variables revealed the same reactions to both the lower and considerably stronger reactions to the highest noise load. Aircraft noise, rail and road traffic noise caused similar after-effects but physiological sleep parameters were most severely affected by rail noise. The equivalent noise level seems to be a suitable predictor for subjectively evaluated sleep quality but not for physiological sleep disturbances.

  20. A Principal Component Analysis Noise Filter Value-Added Procedure to Remove Uncorrelated Noise from Atmospheric Emitted Radiance Interferometer (AERI) Observations

    SciTech Connect

    C. Lo D. D. Turner R. O. Knuteson

    2006-01-31

    This technical report provide a short description of the application of the principle component analysis techniques to remove uncorrelated random noise from ground-based high spectral resolution infrared radiance observations collected by the atmospheric emitted radiance interferometers (AERIs) deployed by the Atmospheric Radiation Measurement (ARM) Program. A general overview of the technique, the input, and output datastreams of the newly generated value-added product, and the data quality checks used are provided. A more complete discussion of the theory and results is given in Turner et al. (2006).

  1. A moving hum filter to suppress rotor noise in high-resolution airborne magnetic data

    USGS Publications Warehouse

    Xia, J.; Doll, W.E.; Miller, R.D.; Gamey, T.J.; Emond, A.M.

    2005-01-01

    A unique filtering approach is developed to eliminate helicopter rotor noise. It is designed to suppress harmonic noise from a rotor that varies slightly in amplitude, phase, and frequency and that contaminates aero-magnetic data. The filter provides a powerful harmonic noise-suppression tool for data acquired with modern large-dynamic-range recording systems. This three-step approach - polynomial fitting, bandpass filtering, and rotor-noise synthesis - significantly reduces rotor noise without altering the spectra of signals of interest. Two steps before hum filtering - polynomial fitting and bandpass filtering - are critical to accurately model the weak rotor noise. During rotor-noise synthesis, amplitude, phase, and frequency are determined. Data are processed segment by segment so that there is no limit on the length of data. The segment length changes dynamically along a line based on modeling results. Modeling the rotor noise is stable and efficient. Real-world data examples demonstrate that this method can suppress rotor noise by more than 95% when implemented in an aeromagnetic data-processing flow. ?? 2005 Society of Exploration Geophysicists. All rights reserved.

  2. Experimental study of noise emitted by circular cylinders with large roughness

    NASA Astrophysics Data System (ADS)

    Alomar, Antoni; Angland, David; Zhang, Xin; Molin, Nicolas

    2014-12-01

    The aerodynamic noise generated by high Reynolds number flow around a bluff body with large surface roughness was investigated. This is a relevant problem in many applications, in particular aircraft landing gear noise. A circular cylinder in cross-flow and a zero-pressure-gradient turbulent boundary layer with various types of roughness was tested in a series of wind tunnel experiments. It has been shown that distributed roughness covering a circular cylinder affects the spectra over the entire frequency range. Roughness noise is dominant at high frequencies, and the peak frequency is well described by Howe's roughness noise model when scaled with the maximum outer velocity. There are differences between hemispherical and cylindrical roughness elements for both the circular cylinder and the zero-pressure-gradient turbulent boundary layer cases, indicating a dependence on roughness shape, not described by the considered roughness noise models. Cylindrical roughness generates higher noise levels at the highest frequencies, especially for the zero-pressure-gradient turbulent boundary layer case. Cable-type roughness aligned with the mean flow does not generate roughness noise, and its spectrum has been found to collapse with the smooth cylinder at medium and high frequencies. At low and medium frequencies the noise spectra have the same features as the smooth cylinder, but with higher shedding peak levels and fall-off levels, despite the decrease in spanwise correlation length. Roughness induces early separation, and thus a shift of the spectra to lower frequencies.

  3. A de-noising algorithm based on wavelet threshold-exponential adaptive window width-fitting for ground electrical source airborne transient electromagnetic signal

    NASA Astrophysics Data System (ADS)

    Ji, Yanju; Li, Dongsheng; Yu, Mingmei; Wang, Yuan; Wu, Qiong; Lin, Jun

    2016-05-01

    The ground electrical source airborne transient electromagnetic system (GREATEM) on an unmanned aircraft enjoys considerable prospecting depth, lateral resolution and detection efficiency, etc. In recent years it has become an important technical means of rapid resources exploration. However, GREATEM data are extremely vulnerable to stationary white noise and non-stationary electromagnetic noise (sferics noise, aircraft engine noise and other human electromagnetic noises). These noises will cause degradation of the imaging quality for data interpretation. Based on the characteristics of the GREATEM data and major noises, we propose a de-noising algorithm utilizing wavelet threshold method and exponential adaptive window width-fitting. Firstly, the white noise is filtered in the measured data using the wavelet threshold method. Then, the data are segmented using data window whose step length is even logarithmic intervals. The data polluted by electromagnetic noise are identified within each window based on the discriminating principle of energy detection, and the attenuation characteristics of the data slope are extracted. Eventually, an exponential fitting algorithm is adopted to fit the attenuation curve of each window, and the data polluted by non-stationary electromagnetic noise are replaced with their fitting results. Thus the non-stationary electromagnetic noise can be effectively removed. The proposed algorithm is verified by the synthetic and real GREATEM signals. The results show that in GREATEM signal, stationary white noise and non-stationary electromagnetic noise can be effectively filtered using the wavelet threshold-exponential adaptive window width-fitting algorithm, which enhances the imaging quality.

  4. Computational modeling of airborne noise demonstrated via benchmarks, supersonic jet, and railway barrier

    NASA Astrophysics Data System (ADS)

    Idres, Moumen Mohammed

    1999-12-01

    In the last several years, there has been a growing demand for mobility to cope with the increasing population. All kinds of transportation have responded to this demand by expanding their networks and introducing new ideas. Rail transportation introduced the idea of high-speed trains and air transportation introduced the idea of high-speed civil transport (HSCT). In this expanding world, the noise legislation is felt to inhibit these plans. Accurate computational methods for noise prediction are in great demand. In the current research, two computational methods are developed to predict noise propagation in air. The first method is based on the finite differencing technique on generalized curvilinear coordinates and it is used to solve linear and nonlinear Euler equations. The dispersion-relation-preserving scheme is adopted for spatial discretization. For temporal integration, either the dispersion-relation-preserving scheme or the low- dispersion-and-dissipation Runge-Kutta scheme is used. Both characteristic and asymptotic nonreflective boundary conditions are studied. Ghost points are employed to satisfy the wall boundary condition. A number of benchmark problems are solved to validate different components of the present method. These include initial pulse in free space, initial pulse reflected from a flat or curved wall, time-periodic train of waves reflected from a flat wall, and oscillatory sink flow. The computed results are compared with the analytical solutions and good agreements are obtained. Using the method developed, the noise of Mach 2.1, perfectly expanded, two- dimensional supersonic jet is computed. The Reynolds- averaged Navier-Stokes equations are solved for the jet mean flow. The instability waves, which are used to excite the jet, are obtained from the solution of the compressible Rayleigh equation. Then, the linearized Euler equations are solved for jet noise. To improve computational efficiency, flow-adapted grid and a multi- block time

  5. Measurement of Underwater Operational Noise Emitted by Wave and Tidal Stream Energy Devices.

    PubMed

    Lepper, Paul A; Robinson, Stephen P

    2016-01-01

    The increasing international growth in the development of marine and freshwater wave and tidal energy harvesting systems has been followed by a growing requirement to understand any associated underwater impact. Radiated noise generated during operation is dependent on the device's physical properties, the sound-propagation environment, and the device's operational state. Physical properties may include size, distribution in the water column, and mechanics/hydrodynamics. The sound-propagation environment may be influenced by water depth, bathymetry, sediment type, and water column acoustic properties, and operational state may be influenced by tidal cycle and wave height among others This paper discusses some of the challenges for measurement of noise characteristics from these devices as well as a case study of the measurement of radiated noise from a full-scale wave energy converter.

  6. Measurement of Underwater Operational Noise Emitted by Wave and Tidal Stream Energy Devices.

    PubMed

    Lepper, Paul A; Robinson, Stephen P

    2016-01-01

    The increasing international growth in the development of marine and freshwater wave and tidal energy harvesting systems has been followed by a growing requirement to understand any associated underwater impact. Radiated noise generated during operation is dependent on the device's physical properties, the sound-propagation environment, and the device's operational state. Physical properties may include size, distribution in the water column, and mechanics/hydrodynamics. The sound-propagation environment may be influenced by water depth, bathymetry, sediment type, and water column acoustic properties, and operational state may be influenced by tidal cycle and wave height among others This paper discusses some of the challenges for measurement of noise characteristics from these devices as well as a case study of the measurement of radiated noise from a full-scale wave energy converter. PMID:26611011

  7. Separation of airborne and structureborne noise radiated by plates constructed of conventional and composite materials with applications for prediction of interior noise paths in propeller driven aircraft. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Mcgary, M. C.

    1986-01-01

    The anticipated application of advanced turboprop propulsion systems and use of composite materials in primary structure is expected to increase the interior noise of future aircraft to unacceptability high levels. The absence of technically and economically feasible noise source-path diagnostic tools has been a primer obstacle in the development of efficient noise control treatments for propeller driven aircraft. A new diagnostic method which permits the separation and prediction of the fully coherent airborne and structureborne components of the sound radiated by plates or thin shells has been developed. Analytical and experimental studies of the proposed method were performed on plates constructed of both conventional and composite materials. The results of the study indicate that the proposed method can be applied to a variety of aircraft materials, could be used in flight, and has fewer encumbrances than the other diagnostic tools currently available. The study has also revealed that the noise radiation of vibrating plates in the low frequency regime due to combined airborne and structureborne inputs possesses a strong synergistic nature. The large influence of the interaction between the airborne and structureborne terms has been hitherto ignored by researchers of aircraft interior noise problems.

  8. Comparative in vitro cytotoxicity assessment of airborne particulate matter emitted from stationary engine fuelled with diesel and waste cooking oil-derived biodiesel

    NASA Astrophysics Data System (ADS)

    Betha, Raghu; Pavagadhi, Shruti; Sethu, Swaminathan; Hande, M. Prakash; Balasubramanian, Rajasekhar

    2012-12-01

    Biodiesel derived from waste cooking oil (WCO) is gaining increased attention as an alternative fuel due to lower particulate emissions and other beneficial factors such as low cost and utilization of waste oil. However, very little information is available on toxicity of airborne particulate matter (PM) emitted from biodiesel combustion. In this study, PM emitted from WCO-derived biodiesel (B100) was analyzed for its toxic potential together with ultra low sulphur diesel (ULSD) as a reference fuel and their blend (B50). Human lung epithelial carcinoma cells (A549) were used for this comparative toxicity study. Results indicate that cytotoxicity and oxidative stress were higher for B100 relative to ULSD. Furthermore, caspase 3/7 activity indicates that cell death induced by B100 was due to either caspase independent apoptotic process or other programmed cell death pathways. The toxicity was also evaluated for different engine load conditions. It was observed that at lower loads there was no significant difference in the toxicological response of B100 and ULSD. However, with increase in the engine load, B100 and B50 showed significantly higher toxicity and oxidative stress compared to ULSD.

  9. European methodology for testing the airborne sound insulation characteristics of noise barriers in situ: experimental verification and comparison with laboratory data

    PubMed

    Garai; Guidorzi

    2000-09-01

    In the frame of the 1994-1997 Standard, Measurement and Testing program, the European Commission funded a research project, named Adrienne, to define new test methods for measuring the intrinsic characteristics of road traffic noise reducing devices in situ. The research team produced innovative methods for testing the sound reflection/absorption and the airborne sound insulation characteristics of noise barriers. These methods are now under consideration at CEN (European Committee for Standardization), to become European standards. The present work reports a detailed verification of the test method for airborne sound insulation over a selection of 17 noise barriers, representative of the Italian and European production. The samples were tested both outdoors, using the new Adrienne method, and in laboratory, following the European standard EN 1793-2. In both cases the single number rating for airborne sound insulation recommended by the European standard was calculated. The new method proved to be easy to use and reliable for all kinds of barriers. It has been found sensitive to quality of mounting, presence of seals, and other details typical of outdoor installations. The comparison between field and laboratory results shows a good correlation, while existing differences can be explained with the different sound fields and mounting conditions between the outdoor and laboratory tests. It is concluded that the Adrienne method is adequate for its intended use. PMID:11008808

  10. Airborne and ground-based measurements of the trace gases and particles emitted from prescribed fires in the United States

    SciTech Connect

    Burling, Ian; Yokelson, Robert J.; Akagi, Sheryl; Urbanski, Shawn; Wold, Cyle E.; Griffith, David WT; Johnson, Timothy J.; Reardon, James; Weise, David

    2011-12-07

    We measured the emission factors for 19 trace gas species and particulate matter (PM2.5) from 14 prescribed fires in chaparral and oak savanna in the southwestern US, as well as pine forest understory in the southeastern US and Sierra Nevada mountains of California. These are likely the most extensive emission factor field measurements for temperate biomass burning to date and the only published emission factors for temperate oak savanna fuels. This study helps close the gap in emissions data available for temperate zone fires relative to tropical biomass burning. We present the first field measurements of the biomass burning emissions of glycolaldehyde, a possible precursor for aqueous phase secondary organic aerosol formation. We also measured the emissions of phenol, another aqueous phase secondary organic aerosol precursor. Our data confirm previous suggestions that urban deposition can impact the NOx emission factors and thus subsequent plume chemistry. For two fires, we measured the emissions in the convective smoke plume from our airborne platform at the same time the unlofted residual smoldering combustion emissions were measured with our ground-based platform after the flame front passed through. The smoke from residual smoldering combustion was characterized by emission factors for hydrocarbon and oxygenated organic species that were up to ten times higher than in the lofted plume, including significant 1,3-butadiene and isoprene concentrations which were not observed in the lofted plume. This should be considered in modeling the air quality impacts of smoke that disperses at ground level, and we show that the normally-ignored unlofted emissions can also significantly impact estimates of total emissions. Preliminary evidence of large emissions of monoterpenes was seen in the residual smoldering spectra, but we have not yet quantified these emissions. These data should lead to an improved capacity to model the impacts of biomass burning in similar

  11. Airborne and ground-based measurements of the trace gases and particles emitted by prescribed fires in the United States

    NASA Astrophysics Data System (ADS)

    Burling, I. R.; Yokelson, R. J.; Akagi, S. K.; Urbanski, S. P.; Wold, C. E.; Griffith, D. W. T.; Johnson, T. J.; Reardon, J.; Weise, D. R.

    2011-12-01

    We have measured emission factors for 19 trace gas species and particulate matter (PM2.5) from 14 prescribed fires in chaparral and oak savanna in the southwestern US, as well as conifer forest understory in the southeastern US and Sierra Nevada mountains of California. These are likely the most extensive emission factor field measurements for temperate biomass burning to date and the only published emission factors for temperate oak savanna fuels. This study helps to close the gap in emissions data available for temperate zone fires relative to tropical biomass burning. We present the first field measurements of the biomass burning emissions of glycolaldehyde, a possible precursor for aqueous phase secondary organic aerosol formation. We also measured the emissions of phenol, another aqueous phase secondary organic aerosol precursor. Our data confirm previous observations that urban deposition can impact the NOx emission factors and thus subsequent plume chemistry. For two fires, we measured both the emissions in the convective smoke plume from our airborne platform and the unlofted residual smoldering combustion emissions with our ground-based platform. The smoke from residual smoldering combustion was characterized by emission factors for hydrocarbon and oxygenated organic species that were up to ten times higher than in the lofted plume, including high 1,3-butadiene and isoprene concentrations which were not observed in the lofted plume. This should be considered in modeling the air quality impacts for smoke that disperses at ground level. We also show that the often ignored unlofted emissions can significantly impact estimates of total emissions. Preliminary evidence suggests large emissions of monoterpenes in the residual smoldering smoke. These data should lead to an improved capacity to model the impacts of biomass burning in similar temperate ecosystems.

  12. Optimization of signal-to-noise ratio for wireless light-emitting diode communication in modern lighting layouts

    NASA Astrophysics Data System (ADS)

    Azizan, Luqman A.; Ab-Rahman, Mohammad S.; Hassan, Mazen R.; Bakar, A. Ashrif A.; Nordin, Rosdiadee

    2014-04-01

    White light-emitting diodes (LEDs) are predicted to be widely used in domestic applications in the future, because they are becoming widespread in commercial lighting applications. The ability of LEDs to be modulated at high speeds offers the possibility of using them as sources for communication instead of illumination. The growing interest in using these devices for both illumination and communication requires attention to combine this technology with modern lighting layouts. A dual-function system is applied to three models of modern lighting layouts: the hybrid corner lighting layout (HCLL), the hybrid wall lighting layout (HWLL), and the hybrid edge lighting layout (HELL). Based on the analysis, the relationship between the space adversity and the signal-to-noise ratio (SNR) performance is demonstrated for each model. The key factor that affects the SNR performance of visible light communication is the reliance on the design parameter that is related to the number and position of LED lights. The model of HWLL is chosen as the best layout, since 61% of the office area is considered as an excellent communication area and the difference between the area classification, Δp, is 22%. Thus, this system is applicable to modern lighting layouts.

  13. Noninvasive, low-noise, fast imaging of blood volume and deoxygenation changes in muscles using light-emitting diode continuous-wave imager

    NASA Astrophysics Data System (ADS)

    Lin, Yuanqing; Lech, Gwen; Nioka, Shoko; Intes, Xavier; Chance, Britton

    2002-08-01

    This article focuses on optimizing the signal to noise ratio (SNR) of a three-wavelength light-emitting diode (LED) near-infrared continuous-wave (cw) imager and its application to in vivo muscle metabolism measurement. The shot-noise limited SNR is derived and calculated to be 2 x104 for the physiological blood concentrations of muscle. Aiming at shot-noise limited SNR performance and fast imaging, we utilize sample and hold circuits to reduce high-frequency noise. These circuits have also been designed to be parallel integrating, through which SNR of 2 x103 and 2 Hz imaging acquisition rate have been achieved when the probe is placed on a muscle model. The noise corresponds to 2 x10-4 optical density error, which suggests an in vitro resolution of 15. 4 nM blood volume and 46.8 nM deoxygenation changes. A 48 dB digital gain control circuit with 256 steps is employed to enlarge the dynamic range of the imager. We utilize cuff ischemia as a living model demonstration and its results are reported. The instrument is applied during exercise to measure the changes of blood volume and deoxygenation, which provides important information about muscle metabolism. We find that the primary source of noise encountered during exercise experiment is from the random motion of muscle. The results demonstrate that the LED cw imager is ideal for the noninvasive study of muscle metabolism.

  14. Interior Noise

    NASA Technical Reports Server (NTRS)

    Mixson, John S.; Wilby, John F.

    1991-01-01

    The generation and control of flight vehicle interior noise is discussed. Emphasis is placed on the mechanisms of transmission through airborne and structure-borne paths and the control of cabin noise by path modification. Techniques for identifying the relative contributions of the various source-path combinations are also discussed along with methods for the prediction of aircraft interior noise such as those based on the general modal theory and statistical energy analysis.

  15. A Low Noise, Microprocessor-Controlled, Internally Digitizing Rotating-Vane Electric Field Mill for Airborne Platforms

    NASA Technical Reports Server (NTRS)

    Bateman, M. G.; Stewart, M. F.; Blakeslee, R. J.; Podgorny, s. J.; Christian, H. J.; Mach, D. M.; Bailey, J. C.; Daskar, D.

    2006-01-01

    This paper reports on a new generation of aircraft-based rotating-vane style electric field mills designed and built at NASA's Marshall Spaceflight Center. The mills have individual microprocessors that digitize the electric field signal at the mill and respond to commands from the data system computer. The mills are very sensitive (1 V/m per bit), have a wide dynamic range (115 dB), and are very low noise (+/-1 LSB). Mounted on an aircraft, these mills can measure fields from +/-1 V/m to +/-500 kV/m. Once-per-second commanding from the data collection computer to each mill allows for precise timing and synchronization. The mills can also be commanded to execute a self-calibration in flight, which is done periodically to monitor the status and health of each mill.

  16. Size distribution of airborne particulate matter emitted by the front-end processing of municipal solid waste feed material for large-scale anaerobic digesters

    SciTech Connect

    Gerrish, H.P.; Narasimhan, R.; Daly, E.L. Jr.; Sengupta, S.; Nemerow, N.L.; Wong, K.V.

    1984-07-01

    A 100-ton/day proof-of-concept facility has been constructed in Pompano Beach, Florida, to examine the feasibility of producing methane-rich gas from the anaerobic digestion of municipal solid waste. One of the possible environmental impacts is from the particulate matter emitted into the atmosphere by the secondary shredding and conveying of light fraction feed material to the digesters. It has been found that the amount of particulate matter emitted into the atmosphere by the front-end processing is an order of magnitude higher when the plant is operating compared to when it is not operating. It has been found that the particle size distribution is bimodal both when the plant is operating as well as when it is not operating. Particle concentrations of episodic nature were found in July 1981 which were four times the concentration found during normal plant operation.

  17. Effects of noise on marine mammals: Executive Summary. Final report

    SciTech Connect

    Richardson, W.J.

    1991-02-01

    The report entitled 'Effects of Noise on Marine Mammals' by W.J. Richardson, C.R. Greene Jr., C.I. Malme and D.H. Thomson (OCS Study MMS 90-0093, LGL Report TA834-1), is a review of published and unpublished literature concerning the effects of manmade noise on marine mammals. Emphasis is given to underwater sounds, but airborne sounds are considered as well. Special attention is given to noise-emitting activities associated, directly or indirectly, with offshore hydrocarbon exploration and development, since that is a dominant interest of the U.S. Minerals Management Service, sponsor of the review. However, reactions of marine mammals to noise from all types of human activities are considered. Special attention is given to species of marine mammals and types of human activities that occur in waters around the United States. However, relevant literature from elsewhere is reviewed.

  18. 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)

  19. Landslide noise.

    PubMed

    Cadman, J D; Goodman, R E

    1967-12-01

    Acoustical monitoring of real landslides has revealed the existence of subaudible noise activity prior to failure and has enabled prediction of the depth of the seat of sliding when conducted in boreholes beneath the surface. Recordings of noise generated in small slopes of moist sand, tilted to failure in laboratory tests, have been analyzed to determine the foci of discrete subaudible noise events. The noises emitted shortly before failure were plotted close to the true sliding surface observed after failure. The foci of earlier events lay either within the central portion of the sliding mass or in a region behind the failure surface. The head and toe zones were devoid of strong seismic activity. PMID:17734306

  20. Fractionation and mobility of Cu, Fe, Mn, Pb and Zn in the road dust retained on noise barriers along expressway - a potential tool for determining the effects of driving conditions on speciation of emitted particulate metals.

    PubMed

    Świetilik, Ryszard; Trojanowska, Marzena; Strzelecka, Monika; Bocho-Janiszewska, Anita

    2015-01-01

    Road dust (RD) retained on noise barriers was used as a monitor of emission of traffic-related metals from expressway. By using SEM/EDX analysis it has been revealed that the main components of this particulate were irregular fine aggregates and tire debris with a ragged porous structure and with inclusions derived from the road surface. The results of chemical fractionation showed that driving conditions influence strongly a distribution pattern of Cu, whereas the atmospheric corrosion process affects a distribution pattern of Zn. The distribution pattern of Cu originating only from vehicle braking emission was “isolated” from the distribution pattern of road traffic copper. The predicted comparative mobilities of the emitted metals form the order: Zn > Cu ≈ Mn > Pb > Fe. The high mobility of zinc (K = 0.61)may create a current inhalation hazard and may be a source of future environmental hazard in the areas adjacent to heavily trafficked roads.

  1. Fractionation and mobility of Cu, Fe, Mn, Pb and Zn in the road dust retained on noise barriers along expressway - a potential tool for determining the effects of driving conditions on speciation of emitted particulate metals.

    PubMed

    Świetilik, Ryszard; Trojanowska, Marzena; Strzelecka, Monika; Bocho-Janiszewska, Anita

    2015-01-01

    Road dust (RD) retained on noise barriers was used as a monitor of emission of traffic-related metals from expressway. By using SEM/EDX analysis it has been revealed that the main components of this particulate were irregular fine aggregates and tire debris with a ragged porous structure and with inclusions derived from the road surface. The results of chemical fractionation showed that driving conditions influence strongly a distribution pattern of Cu, whereas the atmospheric corrosion process affects a distribution pattern of Zn. The distribution pattern of Cu originating only from vehicle braking emission was “isolated” from the distribution pattern of road traffic copper. The predicted comparative mobilities of the emitted metals form the order: Zn > Cu ≈ Mn > Pb > Fe. The high mobility of zinc (K = 0.61)may create a current inhalation hazard and may be a source of future environmental hazard in the areas adjacent to heavily trafficked roads. PMID:25463738

  2. 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.

  3. 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.

  4. 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.

  5. Principal Component Noise Filtering for NAST-I Radiometric Calibration

    NASA Technical Reports Server (NTRS)

    Tian, Jialin; Smith, William L., Sr.

    2011-01-01

    The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Airborne Sounder Testbed- Interferometer (NAST-I) instrument is a high-resolution scanning interferometer that measures emitted thermal radiation between 3.3 and 18 microns. The NAST-I radiometric calibration is achieved using internal blackbody calibration references at ambient and hot temperatures. In this paper, we introduce a refined calibration technique that utilizes a principal component (PC) noise filter to compensate for instrument distortions and artifacts, therefore, further improve the absolute radiometric calibration accuracy. To test the procedure and estimate the PC filter noise performance, we form dependent and independent test samples using odd and even sets of blackbody spectra. To determine the optimal number of eigenvectors, the PC filter algorithm is applied to both dependent and independent blackbody spectra with a varying number of eigenvectors. The optimal number of PCs is selected so that the total root-mean-square (RMS) error is minimized. To estimate the filter noise performance, we examine four different scenarios: apply PC filtering to both dependent and independent datasets, apply PC filtering to dependent calibration data only, apply PC filtering to independent data only, and no PC filters. The independent blackbody radiances are predicted for each case and comparisons are made. The results show significant reduction in noise in the final calibrated radiances with the implementation of the PC filtering algorithm.

  6. 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.

  7. Interior noise prediction methodology: ATDAC theory and validation

    NASA Technical Reports Server (NTRS)

    Mathur, Gopal P.; Gardner, Bryce K.

    1992-01-01

    The Acoustical Theory for Design of Aircraft Cabins (ATDAC) is a computer program developed to predict interior noise levels inside aircraft and to evaluate the effects of different aircraft configurations on the aircraft acoustical environment. The primary motivation for development of this program is the special interior noise problems associated with advanced turboprop (ATP) aircraft where there is a tonal, low frequency noise problem. Prediction of interior noise levels requires knowledge of the energy sources, the transmission paths, and the relationship between the energy variable and the sound pressure level. The energy sources include engine noise, both airborne and structure-borne; turbulent boundary layer noise; and interior noise sources such as air conditioner noise and auxiliary power unit noise. Since propeller and engine noise prediction programs are widely available, they are not included in ATDAC. Airborne engine noise from any prediction or measurement may be input to this program. This report describes the theory and equations implemented in the ATDAC program.

  8. Noise and vibration control for HVAC and piping systems

    SciTech Connect

    Yerges, J.F.; Yerges, J.R.

    1997-10-01

    This article offers engineering advice on how to avoid noise and vibration problems through good mechanical engineering design and strategic communication with other members of the construction team. The design of ducted HVAC systems must address six distinct but related issues--airborne equipment noise, equipment vibration, ductborne fan noise, duct breakout noise, flow generated noise, and ductborne crosstalk. Each and every one of these issues must be addressed, or the design will fail.

  9. Preliminary thoughts on helicopter cabin noise prediction methods

    NASA Astrophysics Data System (ADS)

    Pollard, J. S.

    The problems of predicting helicopter cabin noise are discussed with particular reference to the Lynx helicopter. Available methods such as modal analysis adopted for propeller noise prediction do not cope with the higher frequency discrete tone content of helicopter gear noise, with the airborne and structureborne noise contributions. Statistical energy analysis methods may be the answer but until these are developed, one has to rely on classical noise transmission analysis and transfer function methods.

  10. Noise issues in Kanagawa Prefecture

    NASA Astrophysics Data System (ADS)

    Yokoshima, Shigenori; Tamura, Akihiro

    2001-05-01

    In Kanagawa Prefecture, bordering Tokyo Metropolis and the third most densely populated prefecture in Japan, various noises have caused serious problems in terms of living environment preservation and human health protection. This paper describes present states of noise issues in Kanagawa. Road traffic noise, remaining one of serious pollution issues, was monitored at a total 217 sites along trunk roads in Kanagawa from fiscal year 2000 to 2002. The percentage of the sites that achieve environmental quality standards for road traffic noise was approximately 20%. Noise caused by Tokaido Shinkansen trains, of which the total daily number is 287, also has negative impacts on inhabitants along the railway. As a result of the noise measurement from fiscal year 1994 to 2002, about 80% of the measurement sites exceeded environmental quality standards for Shinkansen railway noise during the years. In the areas surrounding the Atsugi Base, noise generated by training flights damagingly affects inhabitants' daily life. The number of complaints due to the noise was largest among noise issues. Moreover, neighborhood noises, noises emitted during the nighttime operation of bars, restaurants and shops, and noises produced by work in out-of-door yards have recently provoked social issues.

  11. Rotorcraft noise

    NASA Technical Reports Server (NTRS)

    Huston, R. J. (Compiler)

    1982-01-01

    The establishment of a realistic plan for NASA and the U.S. helicopter industry to develop a design-for-noise methodology, including plans for the identification and development of promising noise reduction technology was discussed. Topics included: noise reduction techniques, scaling laws, empirical noise prediction, psychoacoustics, and methods of developing and validing noise prediction methods.

  12. 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.

  13. Determination of airborne nanoparticles from welding operations.

    PubMed

    Gomes, João Fernando Pereira; Albuquerque, Paula Cristina Silva; Miranda, Rosa Maria Mendes; Vieira, Maria Teresa Freire

    2012-01-01

    The aim of this study is to assess the levels of airborne ultrafine particles emitted in welding processes (tungsten inert gas [TIG], metal active gas [MAG] of carbon steel, and friction stir welding [FSW] of aluminum) in terms of deposited area in pulmonary alveolar tract using a nanoparticle surface area monitor (NSAM) analyzer. The obtained results showed the dependence of process parameters on emitted ultrafine particles and demonstrated the presence of ultrafine particles compared to background levels. Data indicated that the process that resulted in the lowest levels of alveolar deposited surface area (ADSA) was FSW, followed by TIG and MAG. However, all tested processes resulted in significant concentrations of ultrafine particles being deposited in humans lungs of exposed workers.

  14. Determination of airborne nanoparticles from welding operations.

    PubMed

    Gomes, João Fernando Pereira; Albuquerque, Paula Cristina Silva; Miranda, Rosa Maria Mendes; Vieira, Maria Teresa Freire

    2012-01-01

    The aim of this study is to assess the levels of airborne ultrafine particles emitted in welding processes (tungsten inert gas [TIG], metal active gas [MAG] of carbon steel, and friction stir welding [FSW] of aluminum) in terms of deposited area in pulmonary alveolar tract using a nanoparticle surface area monitor (NSAM) analyzer. The obtained results showed the dependence of process parameters on emitted ultrafine particles and demonstrated the presence of ultrafine particles compared to background levels. Data indicated that the process that resulted in the lowest levels of alveolar deposited surface area (ADSA) was FSW, followed by TIG and MAG. However, all tested processes resulted in significant concentrations of ultrafine particles being deposited in humans lungs of exposed workers. PMID:22788362

  15. Target detection algorithm for airborne thermal hyperspectral data

    NASA Astrophysics Data System (ADS)

    Marwaha, R.; Kumar, A.; Raju, P. L. N.; Krishna Murthy, Y. V. N.

    2014-11-01

    Airborne hyperspectral imaging is constantly being used for classification purpose. But airborne thermal hyperspectral image usually is a challenge for conventional classification approaches. The Telops Hyper-Cam sensor is an interferometer-based imaging system that helps in the spatial and spectral analysis of targets utilizing a single sensor. It is based on the technology of Fourier-transform which yields high spectral resolution and enables high accuracy radiometric calibration. The Hypercam instrument has 84 spectral bands in the 868 cm-1 to 1280 cm-1 region (7.8 μm to 11.5 μm), at a spectral resolution of 6 cm-1 (full-width-half-maximum) for LWIR (long wave infrared) range. Due to the Hughes effect, only a few classifiers are able to handle high dimensional classification task. MNF (Minimum Noise Fraction) rotation is a data dimensionality reducing approach to segregate noise in the data. In this, the component selection of minimum noise fraction (MNF) rotation transformation was analyzed in terms of classification accuracy using constrained energy minimization (CEM) algorithm as a classifier for Airborne thermal hyperspectral image and for the combination of airborne LWIR hyperspectral image and color digital photograph. On comparing the accuracy of all the classified images for airborne LWIR hyperspectral image and combination of Airborne LWIR hyperspectral image with colored digital photograph, it was found that accuracy was highest for MNF component equal to twenty. The accuracy increased by using the combination of airborne LWIR hyperspectral image with colored digital photograph instead of using LWIR data alone.

  16. Airport noise

    NASA Technical Reports Server (NTRS)

    Pendley, R. E.

    1982-01-01

    The problem of airport noise at several airports and air bases is detailed. Community reactions to the noise, steps taken to reduce jet engine noise, and the effect of airport use restrictions and curfews on air transportation are discussed. The adverse effect of changes in allowable operational noise on airport safety and altenative means for reducing noise pollution are considered. Community-airport relations and public relations are discussed.

  17. Combustion noise

    NASA Technical Reports Server (NTRS)

    Strahle, W. C.

    1977-01-01

    A review of the subject of combustion generated noise is presented. Combustion noise is an important noise source in industrial furnaces and process heaters, turbopropulsion and gas turbine systems, flaring operations, Diesel engines, and rocket engines. The state-of-the-art in combustion noise importance, understanding, prediction and scaling is presented for these systems. The fundamentals and available theories of combustion noise are given. Controversies in the field are discussed and recommendations for future research are made.

  18. Investigation of noise sources and propagation in external gear pumps

    NASA Astrophysics Data System (ADS)

    Opperwall, Timothy J.

    Oil hydraulics is widely accepted as the best technology for transmitting power in many engineering applications due to its advantages in power density, control, layout flexibility, and efficiency. Due to these advantages, hydraulic systems are present in many different applications including construction, agriculture, aerospace, automotive, forestry, medical, and manufacturing, just to identify a few. Many of these applications involve the systems in close proximity to human operators and passengers where noise is one of the main constraints to the acceptance and spread of this technology. As a key component in power transfer, displacement machines can be major sources of noise in hydraulic systems. Thus, investigation into the sources of noise and discovering strategies to reduce noise is a key part of applying fluid power systems to a wider range of applications, as well as improving the performance of current hydraulic systems. The present research aims to leverage previous efforts and develop new models and experimental techniques in the topic of noise generation caused by hydrostatic units. This requires challenging and surpassing current accepted methods in the understanding of noise in fluid power systems. This research seeks to expand on the previous experimental and modeling efforts by directly considering the effect that system and component design changes apply on the total sound power and the sound frequency components emitted from displacement machines and the attached lines. The case of external gear pumps is taken as reference for a new model to understand the generation and transmission of noise from the sources out to the environment. The lumped parameter model HYGESim (HYdraulic GEar machine Simulator) was expanded to investigate the dynamic forces on the solid bodies caused by the pump operation and to predict interactions with the attached system. Vibration and sound radiation were then predicted using a combined finite element and boundary

  19. 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.

  20. Criteria for multiple noises in residential buildings using combined rating system

    NASA Astrophysics Data System (ADS)

    Jeon, Jin Yong; Ryu, Jong Kwan; Jeong, Young

    2005-04-01

    Multiple residential noises such as floor impact, air-borne, bathroom, drainage, and traffic noises were classified using a combined rating system developed from a social noise survey and auditory experiments. The effect of individual noise perception on the evaluation of the overall noise environment was investigated through a questionnaire survey on annoyance, disturbance, and noise sensitivity. In addition, auditory experiments were undertaken to determine the allowable sound pressure level for each residential noise source and the percent satisfaction for individual noise levels. From the results of the survey and the auditory experiments, a combined rating system was developed and annoyance criteria for multiple residential noises were suggested.

  1. 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.

  2. 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.

  3. Community noise

    NASA Technical Reports Server (NTRS)

    Bragdon, C. R.

    1982-01-01

    Airport and community land use planning as they relate to airport noise reduction are discussed. Legislation, community relations, and the physiological effect of airport noise are considered. Noise at the Logan, Los Angeles, and Minneapolis/St. Paul airports is discussed.

  4. Airborne ultrasound enters the ear through the eyes

    NASA Astrophysics Data System (ADS)

    Lenhardt, Martin

    2005-09-01

    Musical spectrum above 20000 Hz has been demonstrated to influence human judgments and physiology. Moreover airborne ultrasonic noise has been implicated in hearing loss, tinnitus, and other subjective effects such as headaches and fullness in the ear. Contact ultrasound, i.e., with a transducer affixed to the skin of the head/neck, is audible; assumed by bone conduction. However, lightly touching the soft tissues of the head, avoiding bone, can also produce audibility. When contact ultrasound is applied to the head, energy from 25 to ~60 kHz can be recorded from the closed eyelid, with care to avoid sensor contact with the orbit. If the same frequency band of noise is passed through a transducer in from of the eye, with just air coupling, the same response is again recordable on the head. An acrylic barrier between the eye and the transducer eliminates the response. Once airborne ultrasound exceeds the impedance mismatch of the eye it readily propagates through the soft tissues of the eye and brain via one of the fluid windows (end lymphatic, perilymphatic or vascular) to the cochlea. The eye fenestration explains how people can detect airborne ultrasonic components in music and develop ear effects from airborne ultrasonic noise.

  5. 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 ...

  6. 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 ...

  7. A Brief History of Airborne Self-Spacing Concepts

    NASA Technical Reports Server (NTRS)

    Abbott, Terence S.

    2009-01-01

    This paper presents a history of seven of the more significant airborne and airborne-assisted aircraft spacing concepts that have been developed and evaluated during the past 40 years. The primary focus of the earlier concepts was on enhancing airport terminal area productivity and reducing air traffic controller workload. The more recent efforts were designed to increase runway throughput through improved aircraft spacing precision at landing. The latest concepts are aimed at supporting more fuel efficient and lower community noise operations while maintaining or increasing runway throughput efficiency.

  8. Light-Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Schubert, E. Fred

    2003-06-01

    Light emitting diodes (LEDs) are devices that are used in a myriad of applications, such as indicator lights in instruments, signage, illuminations, and communication. This graduate textbook covers all aspects of the technology and physics of infrared, visible-spectrum, and white light-emitting diodes (LEDs) made from III-V semiconductors. It reviews elementary properties of LEDs such as the electrical and optical characteristics. Exercises and illustrative examples reinforce the topics discussed.

  9. Rotor noise

    NASA Astrophysics Data System (ADS)

    Schmitz, F. H.

    1991-08-01

    The physical characteristics and sources of rotorcraft noise as they exist today are presented. Emphasis is on helicopter-like vehicles, that is, on rotorcraft in nonaxial flight. The mechanisms of rotor noise are reviewed in a simple physical manner for the most dominant sources of rotorcraft noise. With simple models, the characteristic time- and frequency-domain features of these noise sources are presented for idealized cases. Full-scale data on several rotorcraft are then reviewed to allow for the easy identification of the type and extent of the radiating noise. Methods and limitations of using scaled models to test for several noise sources are subsequently presented. Theoretical prediction methods are then discussed and compared with experimental data taken under very controlled conditions. Finally, some promising noise reduction technology is reviewed.

  10. Rotor noise

    NASA Technical Reports Server (NTRS)

    Schmitz, F. H.

    1991-01-01

    The physical characteristics and sources of rotorcraft noise as they exist today are presented. Emphasis is on helicopter-like vehicles, that is, on rotorcraft in nonaxial flight. The mechanisms of rotor noise are reviewed in a simple physical manner for the most dominant sources of rotorcraft noise. With simple models, the characteristic time- and frequency-domain features of these noise sources are presented for idealized cases. Full-scale data on several rotorcraft are then reviewed to allow for the easy identification of the type and extent of the radiating noise. Methods and limitations of using scaled models to test for several noise sources are subsequently presented. Theoretical prediction methods are then discussed and compared with experimental data taken under very controlled conditions. Finally, some promising noise reduction technology is reviewed.

  11. 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.

  12. 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)

  13. 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.

  14. Light-emitting Diodes

    PubMed Central

    Opel, Daniel R.; Hagstrom, Erika; Pace, Aaron K.; Sisto, Krisanne; Hirano-Ali, Stefanie A.; Desai, Shraddha

    2015-01-01

    Background: In the early 1990s, the biological significance of light-emitting diodes was realized. Since this discovery, various light sources have been investigated for their cutaneous effects. Study design: A Medline search was performed on light-emitting diode lights and their therapeutic effects between 1996 and 2010. Additionally, an open-label, investigator-blinded study was performed using a yellow light-emitting diode device to treat acne, rosacea, photoaging, alopecia areata, and androgenetic alopecia. Results: The authors identified several case-based reports, small case series, and a few randomized controlled trials evaluating the use of four different wavelengths of light-emitting diodes. These devices were classified as red, blue, yellow, or infrared, and covered a wide range of clinical applications. The 21 patients the authors treated had mixed results regarding patient satisfaction and pre- and post-treatment evaluation of improvement in clinical appearance. Conclusion: Review of the literature revealed that differing wavelengths of light-emitting diode devices have many beneficial effects, including wound healing, acne treatment, sunburn prevention, phototherapy for facial rhytides, and skin rejuvenation. The authors’ clinical experience with a specific yellow light-emitting diode device was mixed, depending on the condition being treated, and was likely influenced by the device parameters. PMID:26155326

  15. 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.

  16. Structure-borne noise at hotels

    NASA Astrophysics Data System (ADS)

    Wilson, George Paul; Jue, Deborah A.

    2002-11-01

    Hotels present a challenging environment for building designers to provide suitable noise and vibration isolation between very incompatible uses. While many are familiar with ways to reduce traditional sources of airborne noise and vibration, structure-borne noise and vibration are often overlooked, often with costly repercussions. Structure-borne noise can be very difficult to pinpoint, and troubleshooting the sources of the vibration can be a tedious process. Therefore, the best approach is to avoid the problem altogether during design, with attention to the building construction, potential vibration sources, building uses and equipment locations. In this paper, the relationship between structure-borne vibration and noise are reviewed, typical vibration sources discussed (e.g., aerobic rooms, laundry rooms, mechanical equipment/building services, and subway rail transit), and key details and design guidance to minimize structure-borne noise provided.

  17. 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

  18. Pulsed Doppler lidar airborne scanner

    NASA Technical Reports Server (NTRS)

    Dimarzio, C. A.; Mcvicker, D. B.; Morrow, C. E.; Negus, C. C.

    1985-01-01

    This report covers the work accomplished during the reporting period on Pulsed Doppler Lidar Airborne Scanner and describes plans for the next reporting period. The objectives during the current phase of the contract are divided into four phases. Phase 1 includes ground testing of the system and analysis of data from the 1981 Severe Storms Test Flights. Phase 2 consists of preflight preparation and planning for the 1983 flight series. The flight test itself will be performed during Phase 3, and Phase 4 consists of post-flight analysis and operation of the system after that flight test. The range profile from five samples taken during Flight 10, around 1700 Z is given. The lowest curve is taken from data collected upwind of Mt. Shasta at about 10,000 feet of altitude, in a clear atmosphere, where no signals were observed. It thus is a good representation of the noise level as a function of range. The next curve was taken downwind of the mountain, and shows evidence of atmospheric returns. There is some question as to whether the data are valid at all ranges, or some ranges are contaminated by the others.

  19. Airframe noise

    NASA Astrophysics Data System (ADS)

    Crighton, David G.

    1991-08-01

    Current understanding of airframe noise was reviewed as represented by experiment at model and full scale, by theoretical modeling, and by empirical correlation models. The principal component sources are associated with the trailing edges of wing and tail, deflected trailing edge flaps, flap side edges, leading edge flaps or slats, undercarriage gear elements, gear wheel wells, fuselage and wing boundary layers, and panel vibration, together with many minor protrusions like radio antennas and air conditioning intakes which may contribute significantly to perceived noise. There are also possibilities for interactions between the various mechanisms. With current engine technology, the principal airframe noise mechanisms dominate only at low frequencies, typically less than 1 kHz and often much lower, but further reduction of turbomachinery noise in particular may make airframe noise the principal element of approach noise at frequencies in the sensitive range.

  20. Noise Protection

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Environmental Health Systems puts forth an increasing effort in the U.S. to develop ways of controlling noise, particularly in industrial environments due to Federal and State laws, labor union insistence and new findings relative to noise pollution impact on human health. NASA's Apollo guidance control system aided in the development of a noise protection product, SMART. The basis of all SMART products is SMART compound a liquid plastic mixture with exceptional energy/sound absorbing qualities. The basic compound was later refined for noise protection use.

  1. On the suitability of ISO 16717-1 reference spectra for rating airborne sound insulation.

    PubMed

    Mašović, Draško B; Pavlović, Dragana S Šumarac; Mijić, Miomir M

    2013-11-01

    A standard proposal for rating airborne sound insulation in buildings [ISO 16717-1 (2012)] defines the reference noise spectra. Since their shapes influence the calculated values of single-number descriptors, reference spectra should approximate well typical noise spectra in buildings. There is, however, very little data in the existing literature on a typical noise spectrum in dwellings. A spectral analysis of common noise sources in dwellings is presented in this paper, as a result of an extensive monitoring of various noisy household activities. Apart from music with strong bass content, the proposed "living" reference spectrum overestimates noise levels at low frequencies. PMID:24181985

  2. Light emitting ceramic device

    DOEpatents

    Valentine, Paul; Edwards, Doreen D.; Walker, Jr., William John; Slack, Lyle H.; Brown, Wayne Douglas; Osborne, Cathy; Norton, Michael; Begley, Richard

    2010-05-18

    A light-emitting ceramic based panel, hereafter termed "electroceramescent" panel, is herein claimed. The electroceramescent panel is formed on a substrate providing mechanical support as well as serving as the base electrode for the device. One or more semiconductive ceramic layers directly overlay the substrate, and electrical conductivity and ionic diffusion are controlled. Light emitting regions overlay the semiconductive ceramic layers, and said regions consist sequentially of a layer of a ceramic insulation layer and an electroluminescent layer, comprised of doped phosphors or the equivalent. One or more conductive top electrode layers having optically transmissive areas overlay the light emitting regions, and a multi-layered top barrier cover comprising one or more optically transmissive non-combustible insulation layers overlay said top electrode regions.

  3. [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

  4. Observing the Forest Canopy with a New Ultra-Violet Compact Airborne Lidar

    PubMed Central

    Cuesta, Juan; Chazette, Patrick; Allouis, Tristan; Flamant, Pierre H.; Durrieu, Sylvie; Sanak, Joseph; Genau, Pascal; Guyon, Dominique; Loustau, Denis; Flamant, Cyrille

    2010-01-01

    We have developed a new airborne UV lidar for the forest canopy and deployed it in the Landes forest (France). It is the first one that: (i) operates at 355 nm for emitting energetic pulses of 16 mJ at 20 Hz while fulfilling eye-safety regulations and (ii) is flown onboard an ultra-light airplane for enhanced flight flexibility. Laser footprints at ground level were 2.4 m wide for a flying altitude of 300 m. Three test areas of ∼500 × 500 m2 with Maritime pines of different ages were investigated. We used a threshold method adapted for this lidar to accurately extract from its waveforms detailed forest canopy vertical structure: canopy top, tree crown base and undergrowth heights. Good detection sensitivity enabled the observation of ground returns underneath the trees. Statistical and one-to-one comparisons with ground measurements by field foresters indicated a mean absolute accuracy of ∼1 m. Sensitivity tests on detection threshold showed the importance of signal to noise ratio and footprint size for a proper detection of the canopy vertical structure. This UV-lidar is intended for future innovative applications of simultaneous observation of forest canopy, laser-induced vegetation fluorescence and atmospheric aerosols. PMID:22163608

  5. Observing the forest canopy with a new ultra-violet compact airborne lidar.

    PubMed

    Cuesta, Juan; Chazette, Patrick; Allouis, Tristan; Flamant, Pierre H; Durrieu, Sylvie; Sanak, Joseph; Genau, Pascal; Guyon, Dominique; Loustau, Denis; Flamant, Cyrille

    2010-01-01

    We have developed a new airborne UV lidar for the forest canopy and deployed it in the Landes forest (France). It is the first one that: (i) operates at 355 nm for emitting energetic pulses of 16 mJ at 20 Hz while fulfilling eye-safety regulations and (ii) is flown onboard an ultra-light airplane for enhanced flight flexibility. Laser footprints at ground level were 2.4 m wide for a flying altitude of 300 m. Three test areas of ≈ 500 × 500 m(2) with Maritime pines of different ages were investigated. We used a threshold method adapted for this lidar to accurately extract from its waveforms detailed forest canopy vertical structure: canopy top, tree crown base and undergrowth heights. Good detection sensitivity enabled the observation of ground returns underneath the trees. Statistical and one-to-one comparisons with ground measurements by field foresters indicated a mean absolute accuracy of ≈ 1 m. Sensitivity tests on detection threshold showed the importance of signal to noise ratio and footprint size for a proper detection of the canopy vertical structure. This UV-lidar is intended for future innovative applications of simultaneous observation of forest canopy, laser-induced vegetation fluorescence and atmospheric aerosols.

  6. MLS airborne antenna research

    NASA Technical Reports Server (NTRS)

    Yu, C. L.; Burnside, W. D.

    1975-01-01

    The geometrical theory of diffraction was used to analyze the elevation plane pattern of on-aircraft antennas. The radiation patterns for basic elements (infinitesimal dipole, circumferential and axial slot) mounted on fuselage of various aircrafts with or without radome included were calculated and compared well with experimental results. Error phase plots were also presented. The effects of radiation patterns and error phase plots on the polarization selection for the MLS airborne antenna are discussed.

  7. Airborne forest fire research

    NASA Technical Reports Server (NTRS)

    Mattingly, G. S.

    1974-01-01

    The research relating to airborne fire fighting systems is reviewed to provide NASA/Langley Research Center with current information on the use of aircraft in forest fire operations, and to identify research requirements for future operations. A literature survey, interview of forest fire service personnel, analysis and synthesis of data from research reports and independent conclusions, and recommendations for future NASA-LRC programs are included.

  8. Methods for designing treatments to reduce interior noise of predominant sources and paths in a single engine light aircraft

    NASA Technical Reports Server (NTRS)

    Hayden, Richard E.; Remington, Paul J.; Theobald, Mark A.; Wilby, John F.

    1985-01-01

    The sources and paths by which noise enters the cabin of a small single engine aircraft were determined through a combination of flight and laboratory tests. The primary sources of noise were found to be airborne noise from the propeller and engine casing, airborne noise from the engine exhaust, structureborne noise from the engine/propeller combination and noise associated with air flow over the fuselage. For the propeller, the primary airborne paths were through the firewall, windshield and roof. For the engine, the most important airborne path was through the firewall. Exhaust noise was found to enter the cabin primarily through the panels in the vicinity of the exhaust outlet although exhaust noise entering the cabin through the firewall is a distinct possibility. A number of noise control techniques were tried, including firewall stiffening to reduce engine and propeller airborne noise, to stage isolators and engine mounting spider stiffening to reduce structure-borne noise, and wheel well covers to reduce air flow noise.

  9. Mutagenicity of airborne particles.

    PubMed

    Chrisp, C E; Fisher, G L

    1980-09-01

    The physical and chemical properties of airborne particles are important for the interpretation of their potential biologic significance as genotoxic hazards. For polydisperse particle size distributions, the smallest, most respirable particles are generally the most mutagenic. Particulate collection for testing purposes should be designed to reduce artifact formation and allow condensation of mutagenic compounds. Other critical factors such as UV irradiation, wind direction, chemical reactivity, humidity, sample storage, and temperature of combustion are important. Application of chemical extraction methods and subsequent class fractionation techniques influence the observed mutagenic activity. Particles from urban air, coal fly ash, automobile and diesel exhaust, agricultural burning and welding fumes contain primarily direct-acting mutagens. Cigarette smoke condensate, smoke from charred meat and protein pyrolysates, kerosene soot and cigarette smoke condensates contain primarily mutagens which require metabolic activation. Fractionation coupled with mutagenicity testing indicates that the most potent mutagens are found in the acidic fractions of urban air, coal fly ash, and automobile diesel exhaust, whereas mutagens in rice straw smoke and cigarette smoke condensate are found primarily in the basic fractions. The interaction of the many chemical compounds in complex mixtures from airborne particles is likely to be important in determining mutagenic or comutagenic potentials. Because the mode of exposure is generally frequent and prolonged, the presence of tumor-promoting agents in complex mixtures may be a major factor in evaluation of the carcinogenic potential of airborne particles.

  10. Mammalian airborne allergens.

    PubMed

    Aalberse, Rob C

    2014-01-01

    Historically, horse dandruff was a favorite allergen source material. Today, however, allergic symptoms due to airborne mammalian allergens are mostly a result of indoor exposure, be it at home, at work or even at school. The relevance of mammalian allergens in relation to the allergenic activity of house dust extract is briefly discussed in the historical context of two other proposed sources of house dust allergenic activity: mites and Maillard-type lysine-sugar conjugates. Mammalian proteins involved in allergic reactions to airborne dust are largely found in only 2 protein families: lipocalins and secretoglobins (Fel d 1-like proteins), with a relatively minor contribution of serum albumins, cystatins and latherins. Both the lipocalin and the secretoglobin family are very complex. In some instances this results in a blurred separation between important and less important allergenic family members. The past 50 years have provided us with much detailed information on the genomic organization and protein structure of many of these allergens. However, the complex family relations, combined with the wide range of post-translational enzymatic and non-enzymatic modifications, make a proper qualitative and quantitative description of the important mammalian indoor airborne allergens still a significant proteomic challenge. PMID:24925404

  11. Airborne wireless communication systems, airborne communication methods, and communication methods

    DOEpatents

    Deaton, Juan D.; Schmitt, Michael J.; Jones, Warren F.

    2011-12-13

    An airborne wireless communication system includes circuitry configured to access information describing a configuration of a terrestrial wireless communication base station that has become disabled. The terrestrial base station is configured to implement wireless communication between wireless devices located within a geographical area and a network when the terrestrial base station is not disabled. The circuitry is further configured, based on the information, to configure the airborne station to have the configuration of the terrestrial base station. An airborne communication method includes answering a 911 call from a terrestrial cellular wireless phone using an airborne wireless communication system.

  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. Ultrasonic Vocalizations Emitted by Flying Squirrels

    PubMed Central

    Murrant, Meghan N.; Bowman, Jeff; Garroway, Colin J.; Prinzen, Brian; Mayberry, Heather; Faure, Paul A.

    2013-01-01

    Anecdotal reports of ultrasound use by flying squirrels have existed for decades, yet there has been little detailed analysis of their vocalizations. Here we demonstrate that two species of flying squirrel emit ultrasonic vocalizations. We recorded vocalizations from northern (Glaucomys sabrinus) and southern (G. volans) flying squirrels calling in both the laboratory and at a field site in central Ontario, Canada. We demonstrate that flying squirrels produce ultrasonic emissions through recorded bursts of broadband noise and time-frequency structured frequency modulated (FM) vocalizations, some of which were purely ultrasonic. Squirrels emitted three types of ultrasonic calls in laboratory recordings and one type in the field. The variety of signals that were recorded suggest that flying squirrels may use ultrasonic vocalizations to transfer information. Thus, vocalizations may be an important, although still poorly understood, aspect of flying squirrel social biology. PMID:24009728

  14. Ultrasonic vocalizations emitted by flying squirrels.

    PubMed

    Murrant, Meghan N; Bowman, Jeff; Garroway, Colin J; Prinzen, Brian; Mayberry, Heather; Faure, Paul A

    2013-01-01

    Anecdotal reports of ultrasound use by flying squirrels have existed for decades, yet there has been little detailed analysis of their vocalizations. Here we demonstrate that two species of flying squirrel emit ultrasonic vocalizations. We recorded vocalizations from northern (Glaucomys sabrinus) and southern (G. volans) flying squirrels calling in both the laboratory and at a field site in central Ontario, Canada. We demonstrate that flying squirrels produce ultrasonic emissions through recorded bursts of broadband noise and time-frequency structured frequency modulated (FM) vocalizations, some of which were purely ultrasonic. Squirrels emitted three types of ultrasonic calls in laboratory recordings and one type in the field. The variety of signals that were recorded suggest that flying squirrels may use ultrasonic vocalizations to transfer information. Thus, vocalizations may be an important, although still poorly understood, aspect of flying squirrel social biology. PMID:24009728

  15. Light-Emitting Pickles

    ERIC Educational Resources Information Center

    Vollmer, M.; Mollmann, K-P.

    2015-01-01

    We present experiments giving new insights into the classical light-emitting pickle experiment. In particular, measurements of the spectra and temperatures, as well as high-speed recordings, reveal that light emission is connected to the polarity of the electrodes and the presence of hydrogen.

  16. Covariance analysis of the airborne laser ranging system

    NASA Technical Reports Server (NTRS)

    Englar, T. S., Jr.; Hammond, C. L.; Gibbs, B. P.

    1981-01-01

    The requirements and limitations of employing an airborne laser ranging system for detecting crustal shifts of the Earth within centimeters over a region of approximately 200 by 400 km are presented. The system consists of an aircraft which flies over a grid of ground deployed retroreflectors, making six passes over the grid at two different altitudes. The retroreflector baseline errors are assumed to result from measurement noise, a priori errors on the aircraft and retroreflector positions, tropospheric refraction, and sensor biases.

  17. PHARUS airborne SAR concept

    NASA Astrophysics Data System (ADS)

    Snoeij, Paul; Pouwels, Henk; Koomen, Peter J.; Hoogeboom, Peter

    1995-11-01

    PHARUS (phased array universal SAR) is an airborne SAR concept which is being developed in the Netherlands. The PHARUS system differs from other airborne SARs by the use of a phased array antenna, which provides both for the flexibility in the design as well as for a compact, light-weight instrument that can be carried on small aircraft. The concept allows for the construction of airborne SAR systems on a common generic basis but tailored to specific user needs and can be seen as a preparation for future spaceborne SAR systems using solid state transmitters with electronically steerable phased array antenna. The whole approach is aimed at providing an economic and yet technically sophisticated solution to remote sensing or surveying needs of a specific user. The solid state phased array antenna consists of a collection of radiating patches; the design flexibility for a large part resides in the freedom to choose the number of patches, and thereby the essential radar performance parameters such as resolution and swath width. Another consequence of the use of the phased array antenna is the system's compactness and the possibility to rigidly mount it on a small aircraft. The use of small aircraft of course considerably improves the cost/benefit ratio of the use of airborne SAR. Flight altitude of the system is flexible between about 7,000 and 40,000 feet, giving much operational freedom within the meteo and airspace control limits. In the PHARUS concept the airborne segment is complemented by a ground segment, which consists of a SAR processor, possibly extended by a matching image processing package. (A quick look image is available in real-time on board the aircraft.) The SAR processor is UNIX based and runs on easily available hardware (SUN station). Although the additional image processing software is available, the SAR processing software is nevertheless designed to be able to interface with commercially available image processing software, as well as being able

  18. Airborne Oceanographic Lidar System

    NASA Technical Reports Server (NTRS)

    Bressel, C.; Itzkan, I.; Nunes, J. E.; Hoge, F.

    1977-01-01

    The Airborne Oceanographic Lidar (AOL), a spatially scanning range-gated device installed on board a NASA C-54 aircraft, is described. The AOL system is capable of measuring topographical relief or water depth (bathymetry) with a range resolution of plus or minus 0.3 m in the vertical dimension. The system may also be used to measure fluorescent spectral signatures from 3500 to 8000 A with a resolution of 100 A. Potential applications of the AOL, including sea state measurements, water transparency assessments, oil spill identification, effluent identification and crop cover assessment are also mentioned.

  19. Control of jet noise

    NASA Technical Reports Server (NTRS)

    Schreck, Stefan

    1993-01-01

    This reports describes experiments conducted at the High-Speed Jet Facility at the University of Southern California on supersonic jets. The goal of the study was to develop methods for controlling the noise emitted from supersonic jets by passive and/or active means. Work by Seiner et al (1991) indicates that eddy Mach wave radiation is the dominant noise source in a heated high speed jet. Eddy Mach radiation is caused by turbulent eddies traveling at supersonic speed in the shear layer of the jet. The convection velocity of the eddies decays with increasing distance from the nozzle exit due to the mixing of the jet stream with the ambient fluid. Once the convection speed reaches subsonic velocities, eddy Mach wave radiation ceases. To control noise, a rapid decay of the convection velocity is desired. This may be accomplished by enhanced mixing in the jet. In this study, small aspect ratio rectangular jet nozzles were tested. A flapping mode was noticed in the jets. By amplifying screech components of the jets and destabilizing the jet columns with a collar device, the flapping mode was excited. The result was a rapid decay of the jet velocity. A reduction in eddy Mach radiation in rectangular supersonic jets may be achieved with this device.

  20. Control of jet noise

    NASA Astrophysics Data System (ADS)

    Schreck, Stefan

    This reports describes experiments conducted at the High-Speed Jet Facility at the University of Southern California on supersonic jets. The goal of the study was to develop methods for controlling the noise emitted from supersonic jets by passive and/or active means. Work by Seiner et al (1991) indicates that eddy Mach wave radiation is the dominant noise source in a heated high speed jet. Eddy Mach radiation is caused by turbulent eddies traveling at supersonic speed in the shear layer of the jet. The convection velocity of the eddies decays with increasing distance from the nozzle exit due to the mixing of the jet stream with the ambient fluid. Once the convection speed reaches subsonic velocities, eddy Mach wave radiation ceases. To control noise, a rapid decay of the convection velocity is desired. This may be accomplished by enhanced mixing in the jet. In this study, small aspect ratio rectangular jet nozzles were tested. A flapping mode was noticed in the jets. By amplifying screech components of the jets and destabilizing the jet columns with a collar device, the flapping mode was excited. The result was a rapid decay of the jet velocity. A reduction in eddy Mach radiation in rectangular supersonic jets may be achieved with this device.

  1. White light emitting diodes

    NASA Astrophysics Data System (ADS)

    Baur, J.; Schlotter, P.; Schneider, J.

    Using blue-emitting GaN LEDs on SiC substrate chips as primary light sources, we have fabricated green, yellow, red and white light emitting diodes (LUCOLEDs). The generation of mixed colors, as turquoise and magenta, is also demonstrated. The underlying physical principle is that of luminescence downconversion (Stokes shift), as typical for organic dye molecules and many inorganic phosphors. For white light generation via the LUCOLED principle, the phosphor Y3Al5O12:Ce3+(4f1) is ideally suited. The optical characteristics of Ce3+(4f1) in Y3Al5O12(YAG) are discussed in detail. Possibilities to "tune" the white color by various substitutions in the garnet lattice are shortly outlined.

  2. Airborne concentrations of peanut protein.

    PubMed

    Johnson, Rodney M; Barnes, Charles S

    2013-01-01

    Food allergy to peanut is a significant health problem, and there are reported allergic reactions to peanuts despite not eating or having physical contact with peanuts. It is presumed that an allergic reaction may have occurred from inhalation of airborne peanut allergens. The purpose of this study was to detect the possible concentrations of airborne peanut proteins for various preparations and during specific activities. Separate Ara h 1 and Ara h 2 monoclonal enzyme-linked immunosorbent assays and a polyclonal sandwich enzyme immunoassay for peanuts were used to detect the amount of airborne peanut protein collected using a Spincon Omni 3000 air collector (Sceptor Industries, Inc., Kansas City, MO) under different peanut preparation methods and situations. Air samples were measured for multiple peanut preparations and scenarios. Detectable amounts of airborne peanut protein were measured using a whole peanut immunoassay when removing the shells of roasted peanut. No airborne peanut allergen (Ara h 1 or Ara h 2) or whole peanut protein above the LLD was measured in any of the other peanut preparation collections. Ara h 1, Ara h 2, and polyclonal peanut proteins were detected from water used to boil peanuts. Small amounts of airborne peanut protein were detected in the scenario of removing shells from roasted peanuts; however, Ara h 1 and Ara h 2 proteins were unable to be consistently detected. Although airborne peanut proteins were detected, the concentration of airborne peanut protein that is necessary to elicit a clinical allergic reaction is unknown.

  3. Airborne ballistic camera tracking systems

    NASA Technical Reports Server (NTRS)

    Redish, W. L.

    1976-01-01

    An operational airborne ballistic camera tracking system was tested for operational and data reduction feasibility. The acquisition and data processing requirements of the system are discussed. Suggestions for future improvements are also noted. A description of the data reduction mathematics is outlined. Results from a successful reentry test mission are tabulated. The test mission indicated that airborne ballistic camera tracking systems are feasible.

  4. Airborne concentrations of peanut protein.

    PubMed

    Johnson, Rodney M; Barnes, Charles S

    2013-01-01

    Food allergy to peanut is a significant health problem, and there are reported allergic reactions to peanuts despite not eating or having physical contact with peanuts. It is presumed that an allergic reaction may have occurred from inhalation of airborne peanut allergens. The purpose of this study was to detect the possible concentrations of airborne peanut proteins for various preparations and during specific activities. Separate Ara h 1 and Ara h 2 monoclonal enzyme-linked immunosorbent assays and a polyclonal sandwich enzyme immunoassay for peanuts were used to detect the amount of airborne peanut protein collected using a Spincon Omni 3000 air collector (Sceptor Industries, Inc., Kansas City, MO) under different peanut preparation methods and situations. Air samples were measured for multiple peanut preparations and scenarios. Detectable amounts of airborne peanut protein were measured using a whole peanut immunoassay when removing the shells of roasted peanut. No airborne peanut allergen (Ara h 1 or Ara h 2) or whole peanut protein above the LLD was measured in any of the other peanut preparation collections. Ara h 1, Ara h 2, and polyclonal peanut proteins were detected from water used to boil peanuts. Small amounts of airborne peanut protein were detected in the scenario of removing shells from roasted peanuts; however, Ara h 1 and Ara h 2 proteins were unable to be consistently detected. Although airborne peanut proteins were detected, the concentration of airborne peanut protein that is necessary to elicit a clinical allergic reaction is unknown. PMID:23406937

  5. The development of a noise annoyance scale for rating residential noises

    NASA Astrophysics Data System (ADS)

    Ryu, Jong Kwan; Jeon, Jin Yong

    2005-09-01

    In this study, 5-point and 7-point verbal noise annoyance scales were developed. The 5-point annoyance scale for outside environmental noise was developed from a survey conducted in four Korean cities. An auditory experiment using residential noises such as airborne, bathroom drainage, and traffic noises was conducted to compare the effectiveness of the 5-point and 7-point scales for rating residential indoor noise. Result showed that the 7-point scale yielded more detailed responses to indoor residential noise. In addition, auditory experiments were conducted to develop a noise annoyance scale for the classification of common residential noises. The modifiers used in the scales were selected according to the method proposed by ICBEN (International Commission on the Biological 12Effect of Noise) Team 6. As a result, the difference between the intensity of 21 modifiers investigated in the survey and the auditory experiment was very small. It was also found that the intensity of the selected modifiers in the 7-point noise annoyance scale was highly correlated with noise levels, and that the intensity difference between each pair of successive levels in the 7-point annoyance scale was almost identical.

  6. Airport-related air pollution and noise.

    PubMed

    Cohen, Beverly S; Bronzaft, Arline L; Heikkinen, Maire; Goodman, Jerome; Nádas, Arthur

    2008-02-01

    To provide quantitative evidence of the impact on people of a neighboring metropolitan airport, La Guardia Airport (LGA) in New York City, (1) airborne particulate matter (PM) was measured to determine whether concentration differences could be detected between homes that are upwind and downwind of the airport; (2) 24-hr noise measurements were made in 12 homes near the airport; and (3) the impact of noise was assessed by a Community Wellness and Health Promotion Survey. Particulate matter concentrations were higher during active airport operating hours than during nonoperating hours, and the percent increase varied inversely with distance from the airport. Hourly differences between paired upwind and downwind sites were not remarkable. Residents living near the airport were exposed to noise levels as much as four times greater than those experienced by residents in a quiet, comparison home. Impulse noise events were detected from both aircraft and vehicular traffic. More than 55% of the people living within the flight path were bothered by aircraft noise, and 63% by highway noise; these were significantly higher percentages than for residents in the nonflight area. The change in PM concentrations with distance during operating compared with nonoperating hours; traffic-related impulse noise events; and the elevated annoyance with highway noise, as well as aircraft noise among residents in the flight path area, show airport-related motor vehicle traffic to be a major contributor to the negative impact of airports on people in the surrounding communities.

  7. 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.

  8. Modeling for Airborne Contamination

    SciTech Connect

    F.R. Faillace; Y. Yuan

    2000-08-31

    The objective of Modeling for Airborne Contamination (referred to from now on as ''this report'') is to provide a documented methodology, along with supporting information, for estimating the release, transport, and assessment of dose to workers from airborne radioactive contaminants within the Monitored Geologic Repository (MGR) subsurface during the pre-closure period. Specifically, this report provides engineers and scientists with methodologies for estimating how concentrations of contaminants might be distributed in the air and on the drift surfaces if released from waste packages inside the repository. This report also provides dose conversion factors for inhalation, air submersion, and ground exposure pathways used to derive doses to potentially exposed subsurface workers. The scope of this report is limited to radiological contaminants (particulate, volatile and gaseous) resulting from waste package leaks (if any) and surface contamination and their transport processes. Neutron activation of air, dust in the air and the rock walls of the drift during the preclosure time is not considered within the scope of this report. Any neutrons causing such activation are not themselves considered to be ''contaminants'' released from the waste package. This report: (1) Documents mathematical models and model parameters for evaluating airborne contaminant transport within the MGR subsurface; and (2) Provides tables of dose conversion factors for inhalation, air submersion, and ground exposure pathways for important radionuclides. The dose conversion factors for air submersion and ground exposure pathways are further limited to drift diameters of 7.62 m and 5.5 m, corresponding to the main and emplacement drifts, respectively. If the final repository design significantly deviates from these drift dimensions, the results in this report may require revision. The dose conversion factors are further derived by using concrete of sufficient thickness to simulate the drift

  9. Noise Source for Calibrating a Microwave Polarimeter

    NASA Technical Reports Server (NTRS)

    Piepmeier, Jeffrey R.; Kim, Edward J.

    2006-01-01

    A correlated-noise source has been developed for use in calibrating an airborne or spaceborne Earth-observing correlation microwave polarimeter that operates in a in a pass band that includes a nominal frequency of 10.7 GHz. Deviations from ideal behavior of the hardware of correlation polarimeters are such as to decorrelate the signals measured by such an instrument. A correlated-noise source provides known input signals, measurements of which can be processed to estimate and correct for the decorrelation effect.

  10. Airborne agent concentration analysis

    DOEpatents

    Gelbard, Fred

    2004-02-03

    A method and system for inferring airborne contaminant concentrations in rooms without contaminant sensors, based on data collected by contaminant sensors in other rooms of a building, using known airflow interconnectivity data. The method solves a least squares problem that minimizes the difference between measured and predicted contaminant sensor concentrations with respect to an unknown contaminant release time. Solutions are constrained to providing non-negative initial contaminant concentrations in all rooms. The method can be used to identify a near-optimal distribution of sensors within the building, when then number of available sensors is less than the total number of rooms. This is achieved by having a system-sensor matrix that is non-singular, and by selecting that distribution which yields the lowest condition number of all the distributions considered. The method can predict one or more contaminant initial release points from the collected data.

  11. Airborne Wind Turbine

    SciTech Connect

    2010-09-01

    Broad Funding Opportunity Announcement Project: Makani Power is developing an Airborne Wind Turbine (AWT) that eliminates 90% of the mass of a conventional wind turbine and accesses a stronger, more consistent wind at altitudes of near 1,000 feet. At these altitudes, 85% of the country can offer viable wind resources compared to only 15% accessible with current technology. Additionally, the Makani Power wing can be economically deployed in deep offshore waters, opening up a resource which is 4 times greater than the entire U.S. electrical generation capacity. Makani Power has demonstrated the core technology, including autonomous launch, land, and power generation with an 8 meter wingspan, 20 kW prototype. At commercial scale, Makani Power aims to develop a 600 kW, 28 meter wingspan product capable of delivering energy at an unsubsidized cost competitive with coal, the current benchmark for low-cost power.

  12. Airborne Cloud Computing Environment (ACCE)

    NASA Technical Reports Server (NTRS)

    Hardman, Sean; Freeborn, Dana; Crichton, Dan; Law, Emily; Kay-Im, Liz

    2011-01-01

    Airborne Cloud Computing Environment (ACCE) is JPL's internal investment to improve the return on airborne missions. Improve development performance of the data system. Improve return on the captured science data. The investment is to develop a common science data system capability for airborne instruments that encompasses the end-to-end lifecycle covering planning, provisioning of data system capabilities, and support for scientific analysis in order to improve the quality, cost effectiveness, and capabilities to enable new scientific discovery and research in earth observation.

  13. Hearing and underwater noise exposure

    NASA Astrophysics Data System (ADS)

    Smith, P. F.

    1985-08-01

    Exposure of divers to intense noise in water is increasing, yet there is no general hearing conservation standard for such exposures. This paper reviews three theories of underwater hearing as well as empirical data in order to identify some requirements that an underwater conservation standard must meet. Among the problems considered are hearing sensitivity in water, the frequency and dynamic ranges of the water-immersed ear, and nonauditory effects of underwater sound. It is concluded that: first, no well developed theoretical basis exists for extrapolating hearing conservation standards for airborne noise to the underwater situation; second, the empirical data on underwater hearing suggest that the frequency range covered by an underwater hearing conservation standard must be broader than is the case in air; third, in order to establish a general hearing conservation standard for underwater noise exposure further research is required on the dynamic range of the ear in water; fourth, underwater noise exposure may involve hazards to other body systems than the ear; and fifth, some exposure conditions may interfere with job performance of divers.

  14. Propulsion system noise reduction

    NASA Technical Reports Server (NTRS)

    Feiler, C. E.; Heidelberg, L. J.; Karchmer, A. M.; Lansing, D. L.; Miller, B. A.; Rice, E. J.

    1975-01-01

    The progress in propulsion system noise reduction is reviewed. The noise technology areas discussed include: fan noise; advances in suppression including conventional acoustic treatment, high Mach number inlets, and wing shielding; engine core noise; flap noise from both under-the-wing and over-the-wing powered-lift systems; supersonic jet noise suppression; and the NASA program in noise prediction.

  15. Aircraft and airport noise control prospective outlook

    SciTech Connect

    Shapiro, N.

    1982-01-01

    In a perspective look at aircraft and airport noise control over the past ten years or more - or more is added here because the Federal Aviation Regulation Part 36 of 1969 is a more significant milestone for the air transportation system than is the Noise Control Act of 1972 - we see an appreciable reduction in the noise emitted by newly designed and newly produced airplanes, particularly those powered by the new high bypass engines, but only, at best, a moderate alleviation of airport noise. The change in airport noise exposure was the consequence of the introduction of some new, quieter airplanes into the airlines fleets and some operational modifications or restrictions at the airports.

  16. 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

  17. Development of Jet Noise Power Spectral Laws

    NASA Technical Reports Server (NTRS)

    Khavaran, Abbas; Bridges, James

    2011-01-01

    High-quality jet noise spectral data measured at the Aero-Acoustic Propulsion Laboratory (AAPL) at NASA Glenn is used to develop jet noise scaling laws. A FORTRAN algorithm was written that provides detailed spectral prediction of component jet noise at user-specified conditions. The model generates quick estimates of the jet mixing noise and the broadband shock-associated noise (BBSN) in single-stream, axis-symmetric jets within a wide range of nozzle operating conditions. Shock noise is emitted when supersonic jets exit a nozzle at imperfectly expanded conditions. A successful scaling of the BBSN allows for this noise component to be predicted in both convergent and convergent-divergent nozzles. Configurations considered in this study consisted of convergent and convergent- divergent nozzles. Velocity exponents for the jet mixing noise were evaluated as a function of observer angle and jet temperature. Similar intensity laws were developed for the broadband shock-associated noise in supersonic jets. A computer program called sJet was developed that provides a quick estimate of component noise in single-stream jets at a wide range of operating conditions. A number of features have been incorporated into the data bank and subsequent scaling in order to improve jet noise predictions. Measurements have been converted to a lossless format. Set points have been carefully selected to minimize the instability-related noise at small aft angles. Regression parameters have been scrutinized for error bounds at each angle. Screech-related amplification noise has been kept to a minimum to ensure that the velocity exponents for the jet mixing noise remain free of amplifications. A shock-noise-intensity scaling has been developed independent of the nozzle design point. The computer program provides detailed narrow-band spectral predictions for component noise (mixing noise and shock associated noise), as well as the total noise. Although the methodology is confined to single

  18. Community noise sources and noise control issues

    NASA Technical Reports Server (NTRS)

    Nihart, Gene L.

    1992-01-01

    The topics covered include the following: community noise sources and noise control issues; noise components for turbine bypass turbojet engine (TBE) turbojet; engine cycle selection and noise; nozzle development schedule; NACA nozzle design; NACA nozzle test results; nearly fully mixed (NFM) nozzle design; noise versus aspiration rate; peak noise test results; nozzle test in the Low Speed Aeroacoustic Facility (LSAF); and Schlieren pictures of NACA nozzle.

  19. Community noise sources and noise control issues

    NASA Astrophysics Data System (ADS)

    Nihart, Gene L.

    1992-04-01

    The topics covered include the following: community noise sources and noise control issues; noise components for turbine bypass turbojet engine (TBE) turbojet; engine cycle selection and noise; nozzle development schedule; NACA nozzle design; NACA nozzle test results; nearly fully mixed (NFM) nozzle design; noise versus aspiration rate; peak noise test results; nozzle test in the Low Speed Aeroacoustic Facility (LSAF); and Schlieren pictures of NACA nozzle.

  20. Characterization of aerosols and fibers emitted from composite materials combustion.

    PubMed

    Chivas-Joly, C; Gaie-Levrel, F; Motzkus, C; Ducourtieux, S; Delvallée, A; De Lagos, F; Nevé, S Le; Gutierrez, J; Lopez-Cuesta, J-M

    2016-01-15

    This work investigates the aerosols emitted during combustion of aircraft and naval structural composite materials (epoxy resin/carbon fibers and vinyl ester/glass fibers and carbon nanotubes). Combustion tests were performed at lab-scale using a modified cone calorimeter. The aerosols emitted have been characterized using various metrological devices devoted to the analysis of aerosols. The influence of the nature of polymer matrices, the incorporation of fibers and carbon nanotubes as well as glass reinforcements on the number concentration and the size distribution of airborne particles produced, was studied in the 5 nm-10 μm range. Incorporation of carbon fibers into epoxy resin significantly reduced the total particle number concentration. In addition, the interlaced orientation of carbon fibers limited the particles production compared to the composites with unidirectional one. The carbon nanotubes loading in vinyl ester resin composites influenced the total particles production during the flaming combustion with changes during kinetics emission. Predominant populations of airborne particles generated during combustion of all tested composites were characterized by a PN50 following by PN(100-500). PMID:26348148

  1. Control of Environmental Noise

    ERIC Educational Resources Information Center

    Jensen, Paul

    1973-01-01

    Discusses the physical properties, sources, physiological effects, and legislation pertaining to noise, especially noise characteristics in the community. Indicates that noise reduction steps can be taken more intelligently after determination of the true noise sources and paths. (CC)

  2. 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

  3. Estimating the signal-to-noise ratio of AVIRIS data

    NASA Technical Reports Server (NTRS)

    Curran, Paul J.; Dungan, Jennifer L.

    1988-01-01

    To make the best use of narrowband airborne visible/infrared imaging spectrometer (AVIRIS) data, an investigator needs to know the ratio of signal to random variability or noise (signal-to-noise ratio or SNR). The signal is land cover dependent and varies with both wavelength and atmospheric absorption; random noise comprises sensor noise and intrapixel variability (i.e., variability within a pixel). The three existing methods for estimating the SNR are inadequate, since typical laboratory methods inflate while dark current and image methods deflate the SNR. A new procedure is proposed called the geostatistical method. It is based on the removal of periodic noise by notch filtering in the frequency domain and the isolation of sensor noise and intrapixel variability using the semi-variogram. This procedure was applied easily and successfully to five sets of AVIRIS data from the 1987 flying season and could be applied to remotely sensed data from broadband sensors.

  4. Airborne Laser Polar Nephelometer

    NASA Technical Reports Server (NTRS)

    Grams, Gerald W.

    1973-01-01

    A polar nephelometer has been developed at NCAR to measure the angular variation of the intensity of light scattered by air molecules and particles. The system has been designed for airborne measurements using outside air ducted through a 5-cm diameter airflow tube; the sample volume is that which is common to the intersection of a collimated source beam and the detector field of view within the airflow tube. The source is a linearly polarized helium-neon laser beam. The optical system defines a collimated field-of-view (0.5deg half-angle) through a series of diaphragms located behind a I72-mm focal length objective lens. A photomultiplier tube is located immediately behind an aperture in the focal plane of the objective lens. The laser beam is mechanically chopped (on-off) at a rate of 5 Hz; a two-channel pulse counter, synchronized to the laser output, measures the photomultiplier pulse rate with the light beam both on and off. The difference in these measured pulse rates is directly proportional to the intensity of the scattered light from the volume common to the intersection of the laser beam and the detector field-of-view. Measurements can be made at scattering angles from 15deg to 165deg with reference to the direction of propagation of the light beam. Intermediate angles are obtained by selecting the angular increments desired between these extreme angles (any multiple of 0.1deg can be selected for the angular increment; 5deg is used in normal operation). Pulses provided by digital circuits control a stepping motor which sequentially rotates the detector by pre-selected angular increments. The synchronous photon-counting system automatically begins measurement of the scattered-light intensity immediately after the rotation to a new angle has been completed. The instrument has been flown on the NASA Convair 990 airborne laboratory to obtain data on the complex index of refraction of atmospheric aerosols. A particle impaction device is operated simultaneously

  5. Light Emitting Diodes (LEDs)

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A special lighting technology was developed for space-based commercial plant growth research on NASA's Space Shuttle. Surgeons have used this technology to treat brain cancer on Earth, in two successful operations. The treatment technique, called Photodynamic Therapy, requires the surgeon to use tiny, pinhead-size Light Emitting Diodes (LEDs) (a source that releases long wavelengths of light ) to activate light-sensitive, tumor-treating drugs. 'A young woman operated on in May 1999 has fully recovered with no complications and no evidence of the tumor coming back,' said Dr. Harry Whelan, a pediatric neurologist at the Medical Hospital of Wisconsin in Milwaukee. Laser light has been used for this type of surgery in the past, but the LED light illuminates through all nearby tissues, reaching parts of a tumor that shorter wavelengths of laser light carnot. The new probe is safer because the longer wavelengths of light are cooler than the shorter wavelengths of laser light, making the LED less likely to injure normal brain tissue near the tumor. It can be used for hours at a time while still remaining cool to the touch. The LED light source is compact, about the size of a briefcase, and can be purchased for a fraction of the cost of a laser. The LEDs, developed and managed by NASA's Marshall Space Flight Center, have been used on seven Space Shuttle flights inside the Microgravity Astroculture Facility. This technology has also been successfully used to further commercial research in crop growth.

  6. Light Emitting Diode (LED)

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A special lighting technology was developed for space-based commercial plant growth research on NASA's Space Shuttle. Surgeons have used this technology to treat brain cancer on Earth, in two successful operations. The treatment technique called photodynamic therapy, requires the surgeon to use tiny pinhead-size Light Emitting Diodes (LEDs) (a source releasing long wavelengths of light) to activate light-sensitive, tumor-treating drugs. Laser light has been used for this type of surgery in the past, but the LED light illuminates through all nearby tissues, reaching parts of a tumor that shorter wavelengths of laser light carnot. The new probe is safer because the longer wavelengths of light are cooler than the shorter wavelengths of laser light, making the LED less likely to injure normal brain tissue near the tumor. It can also be used for hours at a time while still remaining cool to the touch. The LED probe consists of 144 tiny pinhead-size diodes, is 9-inches long, and about one-half-inch in diameter. The small balloon aids in even distribution of the light source. The LED light source is compact, about the size of a briefcase, and can be purchased for a fraction of the cost of a laser. The probe was developed for photodynamic cancer therapy by the Marshall Space Flight Center under a NASA Small Business Innovative Research program grant.

  7. Noise pollution resources compendium

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Abstracts of reports concerning noise pollution are presented. The abstracts are grouped in the following areas of activity: (1) sources of noise, (2) noise detection and measurement, (3) noise abatement and control, (4) physical effects of noise and (5) social effects of noise.

  8. Noise exposure in oil mills

    PubMed Central

    Kumar, G. V. Prasanna; Dewangan, K. N.; Sarkar, Amaresh

    2008-01-01

    , USA, equivalent SPL and noise spectrum at each reading was obtained. Noise survey map of equivalent SPL was drawn for each oil mill by drawing contour lines on the sketch of the oil mill between the points of equal SPL. The floor area in the oil mill where SPL exceeded 85 dBA was identified from the noise survey map of each oil mill to determine the causes of high level of noise. Subjective assessment was done during the rest period of workers and it was assessed with personal interview with each worker separately. Demographic information, nature of work, working hours, rest period, experience of working in the mill, degree of noise annoyance, activity interference, and psychological and physiological effects of machine noise on the worker were asked during the interview. These details were noted in a structured form. Statistical Analysis Used: Nil. Results: The noise survey conducted in three renowned oil mills of north-eastern region of India revealed that about 26% of the total workers were exposed to noise level of more than 85 dBA. Further, 10% to 30% floor areas of workrooms, where oil expellers are provided have the SPL of more than 85 dBA. The noise in the oil mills was dominated by low frequency noise. The predominant noise sources in the oil mills were seed cleaner and power transmission system to oil expellers. Poor maintenance of machines and use of bamboo stick to prevent the fall of belt from misaligned pulleys were the main reason of high noise. Noise emitted by the electric motor, table ghani and oil expellers in all the oil mills was well within 85 dBA. Subjective response indicated that about 63% of the total workers felt that noise interfered with their conversation. About 16% each were of the opinion that noise interfered in their work and harmed their hearing. About 5% of workers stated that the workroom noise gave them headaches. Conclusions: The workers engaged in the workrooms of the oil mills are exposed to high noise, which will have

  9. Noise Abatement

    NASA Astrophysics Data System (ADS)

    1983-01-01

    SMART, Sound Modification and Regulated Temperature compound, is a liquid plastic mixture with exceptional energy and sound absorbing qualities. It is derived from a very elastic plastic which was an effective noise abatement material in the Apollo Guidance System. Discovered by a NASA employee, it is marketed by Environmental Health Systems, Inc. (EHS). The product has been successfully employed by a diaper company with noisy dryers and a sugar company with noisy blowers. The company also manufactures an audiometric test booth and acoustical office partitions.

  10. NASA three-laser airborne differential absorption lidar system electronics

    NASA Technical Reports Server (NTRS)

    Allen, R. J.; Copeland, G. D.

    1984-01-01

    The system control and signal conditioning electronics of the NASA three laser airborne differential absorption lidar (DIAL) system are described. The multipurpose DIAL system was developed for the remote measurement of gas and aerosol profiles in the troposphere and lower stratosphere. A brief description and photographs of the majority of electronics units developed under this contract are presented. The precision control system; which includes a master control unit, three combined NASA laser control interface/quantel control units, and three noise pulse discriminator/pockels cell pulser units; is described in detail. The need and design considerations for precision timing and control are discussed. Calibration procedures are included.

  11. Airborne tunable diode laser system for trace gas measurements

    NASA Technical Reports Server (NTRS)

    Sachse, G. W.; Hill, G. F.; Hoell, J. M., Jr.

    1983-01-01

    Sachse et al. (1976) have reported the development of an airborne tunable diode laser (TDL) system, named the Differential Absorption CO Monitor (DACOM). The absorption path was 10 m long and located in the free airstream along the fuselage of a C-54 aircraft. The present investigation is concerned with a modification of the DACOM instrument. Differences between the new instrument and the original one are related to a replacement of the external absorption path with a White cell. The instrument has the capability to suppress TDL excess noise. The laser refrigerator has been redesigned to permit an alternative method of cooling the TDL when electric power is not available.

  12. Airborne laser topographic mapping results

    NASA Technical Reports Server (NTRS)

    Krabill, W. B.; Collins, J. G.; Link, L. E.; Swift, R. N.; Butler, M. L.

    1984-01-01

    The results of terrain mapping experiments utilizing the National Aeronautics and Space Administration (NASA) Airborne Oceanographic Lidar (AOL) over forested areas are presented. The flight tests were conducted as part of a joint NASA/U.S. Army Corps of Engineers (CE) investigation aimed at evaluating the potential of an airborne laser ranging system to provide cross-sectional topographic data on flood plains that are difficult and expensive to survey using conventional techniques. The data described in this paper were obtained in the Wolf River Basin located near Memphis, TN. Results from surveys conducted under winter 'leaves off' and summer 'leaves on' conditions, aspects of day and night operation, and data obtained from decidous and coniferous tree types are compared. Data processing techniques are reviewed. Conclusions relative to accuracy and present limitations of the AOL, and airborne lidar systems in general, to terrain mapping over forested areas are discussed.

  13. An airborne isothermal haze chamber

    NASA Technical Reports Server (NTRS)

    Hindman, E. E.

    1981-01-01

    Thermal gradient diffusion cloud chambers (TGDCC) are used to determine the concentrations of cloud condensation nuclei (CCN) with critical supersaturations greater than or equal to about 0.2%. The CCN concentrations measured with the airborne IHC were lower than theoretically predicted by factors ranging between 7.9 and 9.0. The CCN concentrations measured with the airborne IHC were lower than the concentrations measured with the larger laboratory IHC's by factors ranging between 3.9 and 7.5. The bounds of the supersaturation ranges of the airborne IHC and the CSU-Mee TGDCC do not overlap. Nevertheless, the slopes of the interpolated data between the bounds agree favorably with the theoretical slopes.

  14. WESTERN AIRBORNE CONTAMINANTS ASSESSMENT PROJECT RESEARCH PLAN

    EPA Science Inventory

    The goal of the Western Airborne Contaminants Assessment Project (WACAP) is to assess the deposition of airborne contaminants in Western National Parks, providing regional and local information on exposure, accumulation, impacts, and probable sources. This project is being desig...

  15. Evaluating evaporation from field crops using airborne radiometry and ground-based meteorological data

    USGS Publications Warehouse

    Jackson, R. D.; Moran, M.S.; Gay, L.W.; Raymond, L.H.

    1987-01-01

    Airborne measurements of reflected solar and emitted thermal radiation were combined with ground-based measurements of incoming solar radiation, air temperature, windspeed, and vapor pressure to calculate instantaneous evaporation (LE) rates using a form of the Penman equation. Estimates of evaporation over cotton, wheat, and alfalfa fields were obtained on 5 days during a one-year period. A Bowen ratio apparatus, employed simultaneously, provided ground-based measurements of evaporation. Comparison of the airborne and ground techniques showed good agreement, with the greatest difference being about 12% for the instantaneous values. Estimates of daily (24 h) evaporation were made from the instantaneous data. On three of the five days, the difference between the two techniques was less than 8%, with the greatest difference being 25%. The results demonstrate that airborne remote sensing techniques can be used to obtain spatially distributed values of evaporation over agricultural fields. ?? 1987 Springer-Verlag.

  16. Airborne sound propagation over sea during offshore wind farm piling.

    PubMed

    Van Renterghem, T; Botteldooren, D; Dekoninck, L

    2014-02-01

    Offshore piling for wind farm construction has attracted a lot of attention in recent years due to the extremely high noise emission levels associated with such operations. While underwater noise levels were shown to be harmful for the marine biology, the propagation of airborne piling noise over sea has not been studied in detail before. In this study, detailed numerical calculations have been performed with the Green's Function Parabolic Equation (GFPE) method to estimate noise levels up to a distance of 10 km. Measured noise emission levels during piling of pinpiles for a jacket-foundation wind turbine were assessed and used together with combinations of the sea surface state and idealized vertical sound speed profiles (downwind sound propagation). Effective impedances were found and used to represent non-flat sea surfaces at low-wind sea states 2, 3, and 4. Calculations show that scattering by a rough sea surface, which decreases sound pressure levels, exceeds refractive effects, which increase sound pressure levels under downwind conditions. This suggests that the presence of wind, even when blowing downwind to potential receivers, is beneficial to increase the attenuation of piling sound over the sea. A fully flat sea surface therefore represents a worst-case scenario. PMID:25234870

  17. Airborne Transmission of Bordetella pertussis

    PubMed Central

    Warfel, Jason M.; Beren, Joel; Merkel, Tod J.

    2012-01-01

    Pertussis is a contagious, acute respiratory illness caused by the bacterial pathogen Bordetella pertussis. Although it is widely believed that transmission of B. pertussis occurs via aerosolized respiratory droplets, no controlled study has ever documented airborne transmission of pertussis. We set out to determine if airborne transmission occurs between infected and naive animals, utilizing the baboon model of pertussis. Our results showed that 100% of exposed naive animals became infected even when physical contact was prevented, demonstrating that pertussis transmission occurs via aerosolized respiratory droplets. PMID:22807521

  18. NASA Airborne Lidar 1982-1984 Flights

    Atmospheric Science Data Center

    2016-05-26

    NASA Airborne Lidar 1982-1984 Flights Data from the 1982 NASA Langley Airborne Lidar flights following the eruption of El Chichon ... continuing to January 1984. Transcribed from the following NASA Tech Reports: McCormick, M. P., and M. T. Osborn, Airborne lidar ...

  19. Effects of particle size and velocity on burial depth of airborne particles in glass fiber filters

    SciTech Connect

    Higby, D.P.

    1984-11-01

    Air sampling for particulate radioactive material involves collecting airborne particles on a filter and then determining the amount of radioactivity collected per unit volume of air drawn through the filter. The amount of radioactivity collected is frequently determined by directly measuring the radiation emitted from the particles collected on the filter. Counting losses caused by the particle becoming buried in the filter matrix may cause concentrations of airborne particulate radioactive materials to be underestimated by as much as 50%. Furthermore, the dose calculation for inhaled radionuclides will also be affected. The present study was designed to evaluate the extent to which particle size and sampling velocity influence burial depth in glass-fiber filters. Aerosols of high-fired /sup 239/PuO/sub 2/ were collected at various sampling velocities on glass-fiber filters. The fraction of alpha counts lost due to burial was determined as the ratio of activity detected by direct alpha count to the quantity determined by photon spectrometry. The results show that burial of airborne particles collected on glass-fiber filters appears to be a weak function of sampling velocity and particle size. Counting losses ranged from 0 to 25%. A correction that assumes losses of 10 to 15% would ensure that the concentration of airborne alpha-emitting radionuclides would not be underestimated when glass-fiber filters are used. 32 references, 21 figures, 11 tables.

  20. Evaluation of Airborne Particle Emissions from Commercial Products Containing Carbon Nanotubes

    PubMed Central

    Huang, Guannan; Park, Jae Hong; Cena, Lorenzo G.; Shelton, Betsy L.; Peters, Thomas M.

    2012-01-01

    The emission of the airborne particles from epoxy resin test sticks with different CNT loadings and two commercial products were characterized while sanding with three grit sizes and three disc sander speeds. The total number concentrations, respirable mass concentrations, and particle size number/mass distributions of the emitted particles were measured using a condensation particle counter, an optical particle counter, and a scanning mobility particle sizer. The emitted particles were sampled on a polycarbonate filter and analyzed using electron microscopy. The highest number concentrations (arithmetic mean = 4670 particles/cm3) were produced with coarse sandpaper, 2% (by weight) CNT test sticks and medium disc sander speed, whereas the lowest number concentrations (arithmetic mean = 92 particles/cm3) were produced with medium sandpaper, 2% CNT test sticks and slow disc sander speed. Respirable mass concentrations were highest (arithmetic mean = 1.01 mg/m3) for fine sandpaper, 2% CNT test sticks and medium disc sander speed and lowest (arithmetic mean = 0.20 mg/m3) for medium sandpaper, 0% CNT test sticks and medium disc sander speed. For CNT-epoxy samples, airborne particles were primarily micrometer-sized epoxy cores with CNT protrusions. No free CNTs were observed in airborne samples, except for tests conducted with 4% CNT epoxy. The number concentration, mass concentration, and size distribution of airborne particles generated when products containing CNTs are sanded depends on the conditions of sanding and the characteristics of the material being sanded. PMID:23204914

  1. Algorithms used in the Airborne Lidar Processing System (ALPS)

    USGS Publications Warehouse

    Nagle, David B.; Wright, C. Wayne

    2016-05-23

    The Airborne Lidar Processing System (ALPS) analyzes Experimental Advanced Airborne Research Lidar (EAARL) data—digitized laser-return waveforms, position, and attitude data—to derive point clouds of target surfaces. A full-waveform airborne lidar system, the EAARL seamlessly and simultaneously collects mixed environment data, including submerged, sub-aerial bare earth, and vegetation-covered topographies.ALPS uses three waveform target-detection algorithms to determine target positions within a given waveform: centroid analysis, leading edge detection, and bottom detection using water-column backscatter modeling. The centroid analysis algorithm detects opaque hard surfaces. The leading edge algorithm detects topography beneath vegetation and shallow, submerged topography. The bottom detection algorithm uses water-column backscatter modeling for deeper submerged topography in turbid water.The report describes slant range calculations and explains how ALPS uses laser range and orientation measurements to project measurement points into the Universal Transverse Mercator coordinate system. Parameters used for coordinate transformations in ALPS are described, as are Interactive Data Language-based methods for gridding EAARL point cloud data to derive digital elevation models. Noise reduction in point clouds through use of a random consensus filter is explained, and detailed pseudocode, mathematical equations, and Yorick source code accompany the report.

  2. Algorithms used in the Airborne Lidar Processing System (ALPS)

    USGS Publications Warehouse

    Nagle, David B.; Wright, C. Wayne

    2016-01-01

    The Airborne Lidar Processing System (ALPS) analyzes Experimental Advanced Airborne Research Lidar (EAARL) data—digitized laser-return waveforms, position, and attitude data—to derive point clouds of target surfaces. A full-waveform airborne lidar system, the EAARL seamlessly and simultaneously collects mixed environment data, including submerged, sub-aerial bare earth, and vegetation-covered topographies.ALPS uses three waveform target-detection algorithms to determine target positions within a given waveform: centroid analysis, leading edge detection, and bottom detection using water-column backscatter modeling. The centroid analysis algorithm detects opaque hard surfaces. The leading edge algorithm detects topography beneath vegetation and shallow, submerged topography. The bottom detection algorithm uses water-column backscatter modeling for deeper submerged topography in turbid water.The report describes slant range calculations and explains how ALPS uses laser range and orientation measurements to project measurement points into the Universal Transverse Mercator coordinate system. Parameters used for coordinate transformations in ALPS are described, as are Interactive Data Language-based methods for gridding EAARL point cloud data to derive digital elevation models. Noise reduction in point clouds through use of a random consensus filter is explained, and detailed pseudocode, mathematical equations, and Yorick source code accompany the report.

  3. Airborne Imagery Collections Barrow 2013

    DOE Data Explorer

    Cherry, Jessica; Crowder, Kerri

    2015-07-20

    The data here are orthomosaics, digital surface models (DSMs), and individual frames captured during low altitude airborne flights in 2013 at the Barrow Environmental Observatory. The orthomosaics, thermal IR mosaics, and DSMs were generated from the individual frames using Structure from Motion techniques.

  4. Airborne fungi--a resurvey

    SciTech Connect

    Meyer, G.H.; Prince, H.E.; Raymer, W.J.

    1983-07-01

    A 15-month survey of airborne fungi at 14 geographical stations was conducted to determine the incidence of different fungal genera. Five of these stations were surveyed 25 years earlier. A comparison between previous studies and present surveys revealed similar organisms at each station with slight shifts in frequency of dominant genera.

  5. Tropospheric and Airborne Emission Spectrometers

    NASA Technical Reports Server (NTRS)

    Glavich, Thomas; Beer, Reinhard

    1996-01-01

    X This paper describes the development of two related instruments, the Tropospheric Emission Spectrometer (TES) and the Airborne Emission Spectrometer (AES). Both instruments are infrared imaging Fourier Transform Spectrometers, used for measuring the state of the lower atmosphere, and in particular the measurement of ozone and ozone sources and sinks.

  6. Airborne chemicals and forest health

    SciTech Connect

    Woodman, J.N.; Cowling, E.B.

    1987-02-01

    Over the past few years the possible contribution of acid rain to the problem of forest decline has been a cause of increasing public concern. Research has begun to determine whether airborne chemicals are causing or contributing to visible damage and mortality in eastern spruce-fir and sugar maple forests and to changes in tree growth, usually without visible symptoms, in other parts of North America. This paper describes some of the complex biological relationships that determine health and productivity of forests and that make it difficult to distinguish effects of airborne chemicals from effects of natural stress. It describes four major research approaches for assessment of the effects of airborne chemicals on forests, and it summarizes current understanding of the known and possible effects of airborne chemicals on forest trees in North America and Europe. It also briefly describes the major air quality and forest health research programs in North America, and it assesses how ell these programs are likely to meet information needs during the coming decade. 69 references, 2 figures, 1 table.

  7. Airborne asbestos in public buildings

    SciTech Connect

    Chesson, J.; Hatfield, J.; Schultz, B.; Dutrow, E.; Blake, J. )

    1990-02-01

    The U.S. Environmental Protection Agency sampled air in 49 government-owned buildings (six buildings with no asbestos-containing material, six buildings with asbestos-containing material in generally good condition, and 37 buildings with damaged asbestos-containing material). This is the most comprehensive study to date of airborne asbestos levels in U.S. public buildings during normal building activities. The air outside each building was also sampled. Air samples were analyzed by transmission electron microscopy using a direct transfer preparation technique. The results show an increasing trend in average airborne asbestos levels; outdoor levels are lowest and levels in buildings with damaged asbestos-containing material are highest. However, the measured levels and the differences between indoors and outdoors and between building categories are small in absolute magnitude. Comparable studies from Canada and the UK, although differing in their estimated concentrations, also conclude that while airborne asbestos levels may be elevated in buildings that contain asbestos, levels are generally low. This conclusion does not eliminate the possibility of higher airborne asbestos levels during maintenance or renovation that disturbs the asbestos-containing material.

  8. Effects of Underwater Turbine Noise on Crab Larval Metamorphosis.

    PubMed

    Pine, Matthew K; Jeffs, Andrew G; Radford, Craig A

    2016-01-01

    The development of marine tidal turbines has advanced at a rapid rate over the last decade but with little detailed understanding of the potential noise impacts on invertebrates. Previous research has shown that underwater reef noise plays an important role in mediating metamorphosis in many larval crabs and fishes. New research suggests that underwater estuarine noise may also mediate metamorphosis in estuarine crab larvae and that the noise emitted from underwater tidal and sea-based wind turbines may significantly influence larval metamorphosis in estuarine crabs.

  9. Effects of Underwater Turbine Noise on Crab Larval Metamorphosis.

    PubMed

    Pine, Matthew K; Jeffs, Andrew G; Radford, Craig A

    2016-01-01

    The development of marine tidal turbines has advanced at a rapid rate over the last decade but with little detailed understanding of the potential noise impacts on invertebrates. Previous research has shown that underwater reef noise plays an important role in mediating metamorphosis in many larval crabs and fishes. New research suggests that underwater estuarine noise may also mediate metamorphosis in estuarine crab larvae and that the noise emitted from underwater tidal and sea-based wind turbines may significantly influence larval metamorphosis in estuarine crabs. PMID:26611041

  10. Community Response to Noise

    NASA Astrophysics Data System (ADS)

    Fidell, Sandy

    The primary effects of community noise on residential populations are speech interference, sleep disturbance, and annoyance. This chapter focuses on transportation noise in general and on aircraft noise in particular because aircraft noise is one of the most prominent community noise sources, because airport/community controversies are often the most contentious and widespread, and because industrial and other specialized formsofcommunitynoise generally posemorelocalized problems.

  11. 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.

  12. Polymer light-emitting devices: Light-emitting diodes and light-emitting electrochemical cells

    SciTech Connect

    Heeger, A.J.; Cao, Y.; Pei, Q.; Yu, G.

    1996-10-01

    We will summarize recent progress using two different device configurations: tunneling injection light-emitting diodes (LEDs) and light-emitting electrochemical cells (LECs). In the LEC, a p-n junction diode is created in-situ through simultaneous p-type and n-type electrochemical doping on opposite sides, respectively, of a film of conjugated polymer which contains added electrolyte to provide the necessary counterions for doping. Blue, green and orange emitting LECs have been fabricated. The LEC has been used to directly measure the charge injection energy gap in semiconducting polymers. Simultaneous measurements of the onset of electrochemical doping, electrical injection, and electroluminescence from light-emitting electrochemical cells eliminates the uncertainty in the magnitude of the exciton binding energy; the LEC data are consistent with the semiconductor model in which the exciton binding energy is at most a few times k{sub B}T (at room temperature).

  13. Multicarrier airborne ultrasound transmission with piezoelectric transducers.

    PubMed

    Ens, Alexander; Reindl, Leonhard M

    2015-05-01

    In decentralized localization systems, the received signal has to be assigned to the sender. Therefore, longrange airborne ultrasound communication enables the transmission of an identifier of the sender within the ultrasound signal to the receiver. Further, in areas with high electromagnetic noise or electromagnetic free areas, ultrasound communication is an alternative. Using code division multiple access (CDMA) to transmit data is ineffective in rooms due to high echo amplitudes. Further, piezoelectric transducers generate a narrow-band ultrasound signal, which limits the data rate. This work shows the use of multiple carrier frequencies in orthogonal frequency division multiplex (OFDM) and differential quadrature phase shift keying modulation with narrowband piezoelectric devices to achieve a packet length of 2.1 ms. Moreover, the adapted channel coding increases data rate by correcting transmission errors. As a result, a 2-carrier ultrasound transmission system on an embedded system achieves a data rate of approximately 5.7 kBaud. Within the presented work, a transmission range up to 18 m with a packet error rate (PER) of 13% at 10-V supply voltage is reported. In addition, the transmission works up to 22 m with a PER of 85%. Moreover, this paper shows the accuracy of the frame synchronization over the distance. Consequently, the system achieves a standard deviation of 14 μs for ranges up to 10 m.

  14. Coherent lidar airborne windshear sensor: performance evaluation.

    PubMed

    Targ, R; Kavaya, M J; Huffaker, R M; Bowles, R L

    1991-05-20

    National attention has focused on the critical problem of detecting and avoiding windshear since the crash on 2 Aug. 1985 of a Lockheed L-1011 at Dallas/Fort Worth International Airport. As part of the NASA/FAA National Integrated Windshear Program, we have defined a measurable windshear hazard index that can be remotely sensed from an aircraft, to give the pilot information about the wind conditions he will experience at some later time if he continues along the present flight path. A technology analysis and end-to-end performance simulation measuring signal-to-noise ratios and resulting wind velocity errors for competing coherent laser radar (lidar) systems have been carried out. The results show that a Ho:YAG lidar at a wavelength of 2.1 microm and a CO(2) lidar at 10.6 microm can give the pilot information about the line-of-sight component of a windshear threat from his present position to a region extending 2-4 km in front of the aircraft. This constitutes a warning time of 20-40 s, even in conditions of moderately heavy precipitation. Using these results, a Coherent Lidar Airborne Shear Sensor (CLASS) that uses a Q-switched CO(2) laser at 10.6 microm is being designed and developed for flight evaluation in the fall of 1991.

  15. Multicarrier airborne ultrasound transmission with piezoelectric transducers.

    PubMed

    Ens, Alexander; Reindl, Leonhard M

    2015-05-01

    In decentralized localization systems, the received signal has to be assigned to the sender. Therefore, longrange airborne ultrasound communication enables the transmission of an identifier of the sender within the ultrasound signal to the receiver. Further, in areas with high electromagnetic noise or electromagnetic free areas, ultrasound communication is an alternative. Using code division multiple access (CDMA) to transmit data is ineffective in rooms due to high echo amplitudes. Further, piezoelectric transducers generate a narrow-band ultrasound signal, which limits the data rate. This work shows the use of multiple carrier frequencies in orthogonal frequency division multiplex (OFDM) and differential quadrature phase shift keying modulation with narrowband piezoelectric devices to achieve a packet length of 2.1 ms. Moreover, the adapted channel coding increases data rate by correcting transmission errors. As a result, a 2-carrier ultrasound transmission system on an embedded system achieves a data rate of approximately 5.7 kBaud. Within the presented work, a transmission range up to 18 m with a packet error rate (PER) of 13% at 10-V supply voltage is reported. In addition, the transmission works up to 22 m with a PER of 85%. Moreover, this paper shows the accuracy of the frame synchronization over the distance. Consequently, the system achieves a standard deviation of 14 μs for ranges up to 10 m. PMID:25965683

  16. UHB demonstrator interior noise control flight tests and analysis

    NASA Technical Reports Server (NTRS)

    Simpson, M. A.; Druez, P. M.; Kimbrough, A. J.; Brock, M. P.; Burge, P. L.; Mathur, G. P.; Cannon, M. R.; Tran, B. N.

    1989-01-01

    The measurement and analysis of MD-UHB (McDonnell Douglas Ultra High Bypass) Demonstrator noise and vibration flight test data are described as they relate to passenger cabin noise. The analyses were done to investigate the interior noise characteristics of advanced turboprop aircraft with aft-mounted engines, and to study the effectiveness of selected noise control treatments in reducing passenger cabin noise. The UHB Demonstrator is an MD-80 test aircraft with the left JT8D engine replaced with a prototype UHB engine. For these tests, the UHB engine was a General Electric Unducted Fan, with either 8x8 or 10x8 counter-rotating propeller configurations. Interior noise level characteristics were studied for several altitudes and speeds, with emphasis on high altitude (35,000 ft), high speed (0.75 Mach) cruise conditions. The effectiveness of several noise control treatments was evaluated based on cabin noise measurements. The important airborne and structureborne transmission paths were identified for both tonal and broadband sources using the results of a sound intensity survey, exterior and interior noise and vibration data, and partial coherence analysis techniques. Estimates of the turbulent boundary layer pressure wavenumber-frequency spectrum were made, based on measured fuselage noise levels.

  17. Research Of Airborne Precision Spacing to Improve Airport Arrival Operations

    NASA Technical Reports Server (NTRS)

    Barmore, Bryan E.; Baxley, Brian T.; Murdoch, Jennifer L.

    2011-01-01

    In September 2004, the European Organization for the Safety of Air Navigation (EUROCONTROL) and the United States Federal Aviation Administration (FAA) signed a Memorandum of Cooperation to mutually develop, modify, test, and evaluate systems, procedures, facilities, and devices to meet the need for safe and efficient air navigation and air traffic control in the future. In the United States and Europe, these efforts are defined within the architectures of the Next Generation Air Transportation System (NextGen) Program and Single European Sky Air Traffic Management Research (SESAR) Program respectively. Both programs have identified Airborne Spacing as a critical component, with Automatic Dependent Surveillance Broadcast (ADS-B) as a key enabler. Increased interest in reducing airport community noise and the escalating cost of aviation fuel has led to the use of Continuous Descent Arrival (CDA) procedures to reduce noise, emissions, and fuel usage compared to current procedures. To provide these operational enhancements, arrival flight paths into terminal areas are planned around continuous vertical descents that are closer to an optimum trajectory than those in use today. The profiles are designed to be near-idle descents from cruise altitude to the Final Approach Fix (FAF) and are typically without any level segments. By staying higher and faster than conventional arrivals, CDAs also save flight time for the aircraft operator. The drawback is that the variation of optimized trajectories for different types and weights of aircraft requires the Air Traffic Controller to provide more airspace around an aircraft on a CDA than on a conventional arrival procedure. This additional space decreases the throughput rate of the destination airport. Airborne self-spacing concepts have been developed to increase the throughput at high-demand airports by managing the inter-arrival spacing to be more precise and consistent using on-board guidance. It has been proposed that the

  18. Infrared emitting device and method

    DOEpatents

    Kurtz, Steven R.; Biefeld, Robert M.; Dawson, L. Ralph; Howard, Arnold J.; Baucom, Kevin C.

    1997-01-01

    An infrared emitting device and method. The infrared emitting device comprises a III-V compound semiconductor substrate upon which are grown a quantum-well active region having a plurality of quantum-well layers formed of a ternary alloy comprising InAsSb sandwiched between barrier layers formed of a ternary alloy having a smaller lattice constant and a larger energy bandgap than the quantum-well layers. The quantum-well layers are preferably compressively strained to increase the threshold energy for Auger recombination; and a method is provided for determining the preferred thickness for the quantum-well layers. Embodiments of the present invention are described having at least one cladding layer to increase the optical and carrier confinement in the active region, and to provide for waveguiding of the light generated within the active region. Examples have been set forth showing embodiments of the present invention as surface- and edge-emitting light emitting diodes (LEDs), an optically-pumped semiconductor laser, and an electrically-injected semiconductor diode laser. The light emission from each of the infrared emitting devices of the present invention is in the midwave infrared region of the spectrum from about 2 to 6 microns.

  19. Noise and blast

    NASA Technical Reports Server (NTRS)

    Hodge, D. C.; Garinther, G. R.

    1973-01-01

    Noise and blast environments are described, providing a definition of units and techniques of noise measurement and giving representative booster-launch and spacecraft noise data. The effects of noise on hearing sensitivity and performance are reviewed, and community response to noise exposure is discussed. Physiological, or nonauditory, effects of noise exposure are also treated, as are design criteria and methods for minimizing the noise effects of hearing sensitivity and communications. The low level sound detection and speech reception are included, along with subjective and behavioral responses to noise.

  20. Large aperture scanning airborne lidar

    NASA Technical Reports Server (NTRS)

    Smith, J.; Bindschadler, R.; Boers, R.; Bufton, J. L.; Clem, D.; Garvin, J.; Melfi, S. H.

    1988-01-01

    A large aperture scanning airborne lidar facility is being developed to provide important new capabilities for airborne lidar sensor systems. The proposed scanning mechanism allows for a large aperture telescope (25 in. diameter) in front of an elliptical flat (25 x 36 in.) turning mirror positioned at a 45 degree angle with respect to the telescope optical axis. The lidar scanning capability will provide opportunities for acquiring new data sets for atmospheric, earth resources, and oceans communities. This completed facility will also make available the opportunity to acquire simulated EOS lidar data on a near global basis. The design and construction of this unique scanning mechanism presents exciting technological challenges of maintaining the turning mirror optical flatness during scanning while exposed to extreme temperatures, ambient pressures, aircraft vibrations, etc.

  1. Metals in dust fractions emitted at mechanical workstations.

    PubMed

    Kondej, Dorota; Gawęda, Ewa

    2012-01-01

    Workers at metal machining workstations are exposed to airborne dust particles containing metals and their compounds. Their harmful impact on the workers' health depends on both their chemical composition and their distribution. The aim of this study was to determine the content of metals in dust fractions emitted in the process of mechanical machining of products made of brass, steel and cast iron. Samples taken during grinding, turning and drilling were tested. The concentration of metals in dust fractions was determined with atomic absorption spectrometry. The content of iron, manganese, chromium, zinc, lead, copper and nickel in the dust fractions was highly differentiated depending on the size of the particles, the material and the processes used.

  2. Magnetic airborne survey - geophysical flight

    NASA Astrophysics Data System (ADS)

    de Barros Camara, Erick; Nei Pereira Guimarães, Suze

    2016-06-01

    This paper provides a technical review process in the area of airborne acquisition of geophysical data, with emphasis for magnetometry. In summary, it addresses the calibration processes of geophysical equipment as well as the aircraft to minimize possible errors in measurements. The corrections used in data processing and filtering are demonstrated with the same results as well as the evolution of these techniques in Brazil and worldwide.

  3. Airborne particulate matter in spacecraft

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Acceptability limits and sampling and monitoring strategies for airborne particles in spacecraft were considered. Based on instances of eye and respiratory tract irritation reported by Shuttle flight crews, the following acceptability limits for airborne particles were recommended: for flights of 1 week or less duration (1 mg/cu m for particles less than 10 microns in aerodynamic diameter (AD) plus 1 mg/cu m for particles 10 to 100 microns in AD); and for flights greater than 1 week and up to 6 months in duration (0.2 mg/cu m for particles less than 10 microns in AD plus 0.2 mg/cu m for particles 10 to 100 microns in AD. These numerical limits were recommended to aid in spacecraft atmosphere design which should aim at particulate levels that are a low as reasonably achievable. Sampling of spacecraft atmospheres for particles should include size-fractionated samples of 0 to 10, 10 to 100, and greater than 100 micron particles for mass concentration measurement and elementary chemical analysis by nondestructive analysis techniques. Morphological and chemical analyses of single particles should also be made to aid in identifying airborne particulate sources. Air cleaning systems based on inertial collection principles and fine particle collection devices based on electrostatic precipitation and filtration should be considered for incorporation into spacecraft air circulation systems. It was also recommended that research be carried out in space in the areas of health effects and particle characterization.

  4. NASA Student Airborne Research Program

    NASA Astrophysics Data System (ADS)

    Schaller, E. L.; Shetter, R. E.

    2012-12-01

    The NASA Student Airborne Research Program (SARP) is a unique summer internship program for advanced undergraduates and early graduate students majoring in the STEM disciplines. SARP participants acquire hands-on research experience in all aspects of an airborne research campaign, including flying onboard an major NASA resource used for studying Earth system processes. In summer 2012, thirty-two participants worked in four interdisciplinary teams to study surface, atmospheric, and oceanographic processes. Participants assisted in the operation of instruments onboard the NASA P-3B aircraft where they sampled and measured atmospheric gases and imaged land and water surfaces in multiple spectral bands. Along with airborne data collection, students participated in taking measurements at field sites. Mission faculty and research mentors helped to guide participants through instrument operation, sample analysis, and data reduction. Over the eight-week program, each student developed an individual research project from the data collected and delivered a conference-style final presentation on his/her results. We will discuss the results and effectiveness of the program from the first four summers and discuss plans for the future.

  5. Blue light emitting thiogallate phosphor

    DOEpatents

    Dye, Robert C.; Smith, David C.; King, Christopher N.; Tuenge, Richard T.

    1998-01-01

    A crystalline blue emitting thiogallate phosphor of the formula RGa.sub.2 S.sub.4 :Ce.sub.x where R is selected from the group consisting of calcium, strontium, barium and zinc, and x is from about 1 to 10 atomic percent, the phosphor characterized as having a crystalline microstructure on the size order of from about 100 .ANG. to about 10,000 .ANG. is provided together with a process of preparing a crystalline blue emitting thiogallate phosphor by depositing on a substrate by CVD and resultant thin film electroluminescent devices including a layer of such deposited phosphor on an ordinary glass substrate.

  6. Surface and Airborne Arsenic Concentrations in a Recreational Site near Las Vegas, Nevada, USA

    PubMed Central

    Goossens, Dirk

    2015-01-01

    Elevated concentrations of arsenic, up to 7058 μg g-1 in topsoil and bedrock, and more than 0.03 μg m-3 in air on a 2-week basis, were measured in the Nellis Dunes Recreation Area (NDRA), a very popular off-road area near Las Vegas, Nevada, USA. The elevated arsenic concentrations in the topsoil and bedrock are correlated to outcrops of yellow sandstone belonging to the Muddy Creek Formation (≈ 10 to 4 Ma) and to faults crossing the area. Mineralized fluids moved to the surface through the faults and deposited the arsenic. A technique was developed to calculate airborne arsenic concentrations from the arsenic content in the topsoil. The technique was tested by comparing calculated with measured concentrations at 34 locations in the NDRA, for 3 periods of 2 weeks each. We then applied it to calculate airborne arsenic concentrations for more than 500 locations all over the NDRA. The highest airborne arsenic concentrations occur over sand dunes and other zones with a surficial layer of aeolian sand. Ironically these areas show the lowest levels of arsenic in the topsoil. However, they are highly susceptible to wind erosion and emit very large amounts of sand and dust during episodes of strong winds, thereby also emitting much arsenic. Elsewhere in the NDRA, in areas not or only very slightly affected by wind erosion, airborne arsenic levels equal the background level for airborne arsenic in the USA, approximately 0.0004 μg m-3. The results of this study are important because the NDRA is visited by more than 300,000 people annually. PMID:25897667

  7. Airborne Particle Size Distribution Measurements at USDOE Fernald

    SciTech Connect

    Harley, N.H.; Chittaporn, P.; Heikkinen, M.; Medora, R.; Merrill, R.

    2003-03-27

    There are no long term measurements of the particle size distribution and concentration of airborne radionuclides at any USDOE facility except Fernald. Yet the determinant of lung dose is the particle size, determining the airway and lower lung deposition. Beginning in 2000, continuous (6 to 8 weeks) measurements of the aerosol particle size distribution have been made with a miniature sampler developed under EMSP. Radon gas decays to a chain of four short lived solid radionuclides that attach immediately to the resident atmospheric aerosol. These in turn decay to long lived polonium 210. Alpha emitting polonium is a tracer for any atmospheric aerosol. Six samplers at Fernald and four at QC sites in New Jersey show a difference in both polonium concentration and size distribution with the winter measurements being higher/larger than summer by almost a factor of two at all locations. EMSP USDOE Contract DE FG07 97ER62522.

  8. Target contrast considerations in millimeter wave radiometry for airborne navigation

    NASA Technical Reports Server (NTRS)

    Mayer, A.

    1971-01-01

    Target signal requirements for aircraft navigation systems that use radiometric receivers which map thermally emitted power radiated by terrain or power radiated by ground-based beacons are discussed. For selected millimeter wavelength bands, microwaves suffer relatively little degradation by absorption or scattering on passage through the atmosphere, despite extreme weather variations. Interest centers on 8-millimeter waves because of component availability, portability (small size), high image resolution, and all-weather capability at this wavelength. The idea of radiometric airborne navigation is introduced. Elements of radiometry, terrain radiation, and atmospheric transmission characteristics are reviewed. Data pertaining to these elements at 8 mm wavelength are collected. Calculation of radiometric contrasts is discussed for some simple models of terrain targets.

  9. Noise, Health, and Architecture.

    ERIC Educational Resources Information Center

    Beranek, Leo L.

    There is reasonable agreement that hearing impairment is related to noise exposure. This hearing loss due to noise is considered a serious health injury, but there is still difficulty in delineating the importance of noise related to people's general non-auditory well-being and health. Beside hearing loss, noise inhibits satisfactory speech…

  10. Research In Helicopter Noise

    NASA Technical Reports Server (NTRS)

    Yu, Yung H.; Schmitz, Frederic H.; Morse, Andrew H.

    1991-01-01

    Progress in aeroacoustical theory and experiments reviewed. Report summarizes continuing U.S. Army programs of research into causes of noise generated by helicopters. Topics of study include high-speed impulsive noise, blade/vortex-interaction noise, and low-frequency harmonic noise.

  11. Active Noise Control for Dishwasher noise

    NASA Astrophysics Data System (ADS)

    Lee, Nokhaeng; Park, Youngjin

    2016-09-01

    The dishwasher is a useful home appliance and continually used for automatically washing dishes. It's commonly placed in the kitchen with built-in style for practicality and better use of space. In this environment, people are easily exposed to dishwasher noise, so it is an important issue for the consumers, especially for the people living in open and narrow space. Recently, the sound power levels of the noise are about 40 - 50 dBA. It could be achieved by removal of noise sources and passive means of insulating acoustical path. For more reduction, such a quiet mode with the lower speed of cycle has been introduced, but this deteriorates the washing capacity. Under this background, we propose active noise control for dishwasher noise. It is observed that the noise is propagating mainly from the lower part of the front side. Control speakers are placed in the part for the collocation. Observation part of estimating sound field distribution and control part of generating the anti-noise are designed for active noise control. Simulation result shows proposed active noise control scheme could have a potential application for dishwasher noise reduction.

  12. Surface-emitting laser logic

    SciTech Connect

    Olbright, G.R.; Bryan, R.P.; Brennan, T.M.; Lear, K.; Poirier, G.E.; Fu, W.S. ); Jewell, J.L.; Lee, Y.H. )

    1990-10-31

    We describe a new class of optical logic devices which consist of integrated phototransistors and surface-emitting lasers. The devices function as optical neurons having high gain and, as arrays, are ideal for neural networks, parallel optical signal processing and optical computing applications. 3 refs., 3 figs.

  13. Broadband light-emitting diode

    DOEpatents

    Fritz, I.J.; Klem, J.F.; Hafich, M.J.

    1998-07-14

    A broadband light-emitting diode is disclosed. The broadband light-emitting diode (LED) comprises a plurality of III-V compound semiconductor layers grown on a semiconductor substrate, with the semiconductor layers including a pair of cladding layers sandwiched about a strained-quantum-well active region having a plurality of different energy bandgaps for generating light in a wavelength range of about 1.3--2 {micro}m. In one embodiment of the present invention, the active region may comprise a first-grown quantum-well layer and a last-grown quantum-well layer that are oppositely strained; whereas in another embodiment of the invention, the active region is formed from a short-period superlattice structure (i.e. a pseudo alloy) comprising alternating thin layers of InGaAs and InGaAlAs. The use a short-period superlattice structure for the active region allows different layers within the active region to be simply and accurately grown by repetitively opening and closing one or more shutters in an MBE growth apparatus to repetitively switch between different growth states therein. The broadband LED may be formed as either a surface-emitting LED or as an edge-emitting LED for use in applications such as chemical sensing, fiber optic gyroscopes, wavelength-divisionmultiplexed (WDM) fiber-optic data links, and WDM fiber-optic sensor networks for automobiles and aircraft. 10 figs.

  14. Infrared emitting device and method

    DOEpatents

    Kurtz, S.R.; Biefeld, R.M.; Dawson, L.R.; Howard, A.J.; Baucom, K.C.

    1997-04-29

    The infrared emitting device comprises a III-V compound semiconductor substrate upon which are grown a quantum-well active region having a plurality of quantum-well layers formed of a ternary alloy comprising InAsSb sandwiched between barrier layers formed of a ternary alloy having a smaller lattice constant and a larger energy bandgap than the quantum-well layers. The quantum-well layers are preferably compressively strained to increase the threshold energy for Auger recombination; and a method is provided for determining the preferred thickness for the quantum-well layers. Embodiments of the present invention are described having at least one cladding layer to increase the optical and carrier confinement in the active region, and to provide for waveguiding of the light generated within the active region. Examples have been set forth showing embodiments of the present invention as surface- and edge-emitting light emitting diodes (LEDs), an optically-pumped semiconductor laser, and an electrically-injected semiconductor diode laser. The light emission from each of the infrared emitting devices of the present invention is in the midwave infrared region of the spectrum from about 2 to 6 microns. 8 figs.

  15. Broadband light-emitting diode

    DOEpatents

    Fritz, Ian J.; Klem, John F.; Hafich, Michael J.

    1998-01-01

    A broadband light-emitting diode. The broadband light-emitting diode (LED) comprises a plurality of III-V compound semiconductor layers grown on a semiconductor substrate, with the semiconductor layers including a pair of cladding layers sandwiched about a strained-quantum-well active region having a plurality of different energy bandgaps for generating light in a wavelength range of about 1.3-2 .mu.m. In one embodiment of the present invention, the active region may comprise a first-grown quantum-well layer and a last-grown quantum-well layer that are oppositely strained; whereas in another embodiment of the invention, the active region is formed from a short-period superlattice structure (i.e. a pseudo alloy) comprising alternating thin layers of InGaAs and InGaAlAs. The use a short-period superlattice structure for the active region allows different layers within the active region to be simply and accurately grown by repetitively opening and closing one or more shutters in an MBE growth apparatus to repetitively switch between different growth states therein. The broadband LED may be formed as either a surface-emitting LED or as an edge-emitting LED for use in applications such as chemical sensing, fiber optic gyroscopes, wavelength-division-multiplexed (WDM) fiber-optic data links, and WDM fiber-optic sensor networks for automobiles and aircraft.

  16. 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.

  17. Airborne HCl - CO sensing system

    NASA Technical Reports Server (NTRS)

    Bartle, E. R.; Hall, G.

    1977-01-01

    A system for measuring air pollutants in-situ using an aircraft was designed, fabricated, and tested. The system is based upon a technique called Gas Filter Correlation (GFC) which provides for high sensitivity and specificity in the presence of interfering species. This particular system was designed for measuring hydrochloric acid and carbon monoxide gases emitted from rocket exhaust effluents.

  18. Helicopter rotor trailing edge noise. [noise prediction

    NASA Technical Reports Server (NTRS)

    Schlinker, R. H.; Amier, R. K.

    1981-01-01

    A two dimensional section of a helicopter main rotor blade was tested in an acoustic wind tunnel at close to full-scale Reynolds numbers to obtain boundary layer data and acoustic data for use in developing an acoustic scaling law and testing a first principles trailing edge noise theory. Results were extended to the rotating frame coordinate system to develop a helicopter rotor trailing edge noise prediction. Comparisons of the calculated noise levels with helicopter flyover spectra demonstrate that trailing edge noise contributes significantly to the total helicopter noise spectrum at high frequencies. This noise mechanism is expected to control the minimum rotor noise. In the case of noise radiation from a local blade segment, the acoustic directivity pattern is predicted by the first principles trailing edge noise theory. Acoustic spectra are predicted by a scaling law which includes Mach number, boundary layer thickness and observer position. Spectrum shape and sound pressure level are also predicted by the first principles theory but the analysis does not predict the Strouhal value identifying the spectrum peak.

  19. General Aviation Interior Noise. Part 1; Source/Path Identification

    NASA Technical Reports Server (NTRS)

    Unruh, James F.; Till, Paul D.; Palumbo, Daniel L. (Technical Monitor)

    2002-01-01

    There were two primary objectives of the research effort reported herein. The first objective was to identify and evaluate noise source/path identification technology applicable to single engine propeller driven aircraft that can be used to identify interior noise sources originating from structure-borne engine/propeller vibration, airborne propeller transmission, airborne engine exhaust noise, and engine case radiation. The approach taken to identify the contributions of each of these possible sources was first to conduct a Principal Component Analysis (PCA) of an in-flight noise and vibration database acquired on a Cessna Model 182E aircraft. The second objective was to develop and evaluate advanced technology for noise source ranking of interior panel groups such as the aircraft windshield, instrument panel, firewall, and door/window panels within the cabin of a single engine propeller driven aircraft. The technology employed was that of Acoustic Holography (AH). AH was applied to the test aircraft by acquiring a series of in-flight microphone array measurements within the aircraft cabin and correlating the measurements via PCA. The source contributions of the various panel groups leading to the array measurements were then synthesized by solving the inverse problem using the boundary element model.

  20. The Role of Aircraft Motion in Airborne Gravity Data Quality

    NASA Astrophysics Data System (ADS)

    Childers, V. A.; Damiani, T.; Weil, C.; Preaux, S. A.

    2015-12-01

    Many factors contribute to the quality of airborne gravity data measured with LaCoste and Romberg-type sensors, such as the Micro-g LaCoste Turnkey Airborne Gravity System used by the National Geodetic Survey's GRAV-D (Gravity for the Redefinition of the American Vertical Datum) Project. For example, it is well documented that turbulence is a big factor in the overall noise level of the measurement. Turbulence is best controlled by avoidance; thus flights in the GRAV-D Project are only undertaken when the predicted wind speeds at flight level are ≤ 40 kts. Tail winds are known to be particularly problematic. The GRAV-D survey operates on a number of aircraft in a variety of wind conditions and geographic locations, and an obvious conclusion from our work to date is that the aircraft itself plays an enormous role in the quality of the airborne gravity measurement. We have identified a number of features of the various aircraft which can be determined to play a role: the autopilot, the size and speed of the aircraft, inherent motion characteristics of the airframe, tip tanks and other modifications to the airframe to reduce motion, to name the most important. This study evaluates the motion of a number of the GRAV-D aircraft and looks at the correlation between this motion and the noise characteristics of the gravity data. The GRAV-D Project spans 7 years and 42 surveys, so we have a significant body of data for this evaluation. Throughout the project, the sensor suite has included an inertial measurement unit (IMU), first the Applanix POSAv, and then later the Honeywell MicroIRS IMU as a part of a NovAtel SPAN GPS/IMU system. We compare the noise characteristics of the data with measures of aircraft motion (via pitch, roll, and yaw captured by the IMU) using a variety of statistical tools. It is expected that this comparison will support the conclusion that certain aircraft tend to work well with this type of gravity sensor while others tend to be problematic in

  1. Resolution analyses for selecting an appropriate airborne electromagnetic (AEM) system

    NASA Astrophysics Data System (ADS)

    Christensen, Niels B. 13Lawrie, Ken C.

    2012-07-01

    The choice of an appropriate airborne electromagnetic system for a given task should be based on a comparative analysis of candidate systems, consisting of both theoretical considerations and field studies including test lines. It has become common practice to quantify the system resolution for a series of models relevant to the survey area by comparing the sum over the data of squares of noise-normalised derivatives. We compare this analysis method with a resolution analysis based on the posterior covariance matrix of an inversion formulation. Both of the above analyses depend critically on the noise models of the systems being compared. A reasonable estimate of data noise and other sources of error is therefore of primary importance. However, data processing and noise reduction procedures, as well as other system parameters important for the modelling, are commonly proprietary, and generally it is not possible to verify whether noise figures have been arrived at by reasonable means. Consequently, it is difficult - sometimes impossible - to know if a comparative analysis has a sound basis. Nevertheless, in the real world choices have to be made, a comparative system analysis is necessary and has to be approached in a pragmatic way involving a range of different aspects. In this paper, we concentrate on the resolution analysis perspective and demonstrate that the inversion analysis must be preferred over the derivative analysis because it takes parameter coupling into account, and, furthermore, that the derivative analysis generally overestimates the resolution capability. Finally we show that impulse response data are to be preferred over step response data for near-surface resolution.

  2. Characterization of aerosol emitted by the combustion of nanocomposites

    NASA Astrophysics Data System (ADS)

    Motzkus, C.; Chivas-Joly, C.; Guillaume, E.; Ducourtieux, S.; Saragoza, L.; Lesenechal, D.; Macé, T.

    2011-07-01

    Day after day, new applications using nanoparticles appear in industry, increasing the probability to find these particles in the workplace as well as in ambient air. As epidemiological studies have shown an association between increased particulate air pollution and adverse health effects in susceptible members of the population, it is particularly important to characterize aerosols emitted by different sources of emission, during the combustion of composites charged with nanoparticles for example. The present study is led in the framework of the NANOFEU project, supported by the French Research Agency (ANR), in order to characterize the fire behaviour of polymers charged with suitable nanoparticles and make an alternative to retardant systems usually employed. To determine the impact of these composites on the emission of airborne particles produced during their combustions, an experimental setup has been developed to measure the mass distribution in the range of 30 nm - 10 μm and the number concentration of submicrometric particles of the produced aerosol. A comparison is performed on the aerosol emitted during the combustion of several polymers alone (PMMA, PA-6), polymers containing nanofillers (silica, alumina, and carbon nanotubes) and polymers containing both nanofillers and a conventional flame retardant system (ammonium polyphosphate). The results on the morphology of particles were also investigated using AFM.

  3. Geophex airborne unmanned survey system

    SciTech Connect

    Won, I.J.; Taylor, D.W.A.

    1995-03-01

    The purpose of this effort is to design, construct, and evaluate a portable, remotely-piloted, airborne, geophysical survey system. This nonintrusive system will provide {open_quotes}stand-off{close_quotes} capability to conduct surveys and detect buried objects, structures, and conditions of interest at hazardous locations. This system permits two operators to rapidly conduct geophysical characterization of hazardous environmental sites. During a survey, the operators remain remote from, but within visual distance, of, the site. The sensor system never contacts the Earth, but can be positioned near the ground so that weak anomalies can be detected.

  4. Airborne wavemeter validation and calibration

    NASA Technical Reports Server (NTRS)

    Goad, Joseph H., Jr.; Rinsland, Pamela L.; Kist, Edward H., Jr.; Geier, Erika B.; Banziger, Curtis G.

    1992-01-01

    This manuscript outlines a continuing effort to validate and verify the performance of an airborne autonomous wavemeter for tuning solid state lasers to a desired wavelength. The application is measuring the vertical profiles of atmospheric water vapor using a differential absorption lidar (DIAL) technique. Improved wavemeter performance data for varying ambient temperatures are presented. This resulted when the electronic grounding and shielding were improved. The results with short pulse duration lasers are also included. These lasers show that similar performance could be obtained with lasers operating in the continuous and the pulsed domains.

  5. Geophex Airborne Unmanned Survey System

    SciTech Connect

    Won, I.J.; Keiswetter, D.

    1995-10-01

    The purpose of this effort is to design, construct, and evaluate a portable, remotely-piloted, airborne, geophysical survey system. This non-intrusive system will provide {open_quotes}stand-off{close_quotes} capability to conduct surveys and detect buried objects, structures, and conditions of interest at hazardous locations. This system permits rapid geophysical characterization of hazardous environmental sites. During a survey, the operators remain remote from, but within visual distance of, the site. The sensor system never contacts the Earth, but can be positioned near the ground so that weak geophysical anomalies can be detected.

  6. Airborne Research Experience for Educators

    NASA Astrophysics Data System (ADS)

    Costa, V. B.; Albertson, R.; Smith, S.; Stockman, S. A.

    2009-12-01

    The Airborne Research Experience for Educators (AREE) Program, conducted by the NASA Dryden Flight Research Center Office of Education in partnership with the AERO Institute, NASA Teaching From Space Program, and California State University Fullerton, is a complete end-to-end residential research experience in airborne remote sensing and atmospheric science. The 2009 program engaged ten secondary educators who specialize in science, technology, engineering or mathematics in a 6-week Student Airborne Research Program (SARP) offered through NSERC. Educators participated in collection of in-flight remote sensor data during flights aboard the NASA DC-8 as well as in-situ research on atmospheric chemistry (bovine emissions of methane); algal blooms (remote sensing to determine location and degree of blooms for further in-situ analysis); and crop classification (exploration of how drought conditions in Central California have impacted almond and cotton crops). AREE represents a unique model of the STEM teacher-as-researcher professional development experience because it asks educators to participate in a research experience and then translate their experiences into classroom practice through the design, implementation, and evaluation of instructional materials that emphasize the scientific research process, inquiry-based investigations, and manipulation of real data. Each AREE Master Educator drafted a Curriculum Brief, Teachers Guide, and accompanying resources for a topic in their teaching assignment Currently, most professional development programs offer either a research experience OR a curriculum development experience. The dual nature of the AREE model engaged educators in both experiences. Educators’ content and pedagogical knowledge of STEM was increased through the review of pertinent research articles during the first week, attendance at lectures and workshops during the second week, and participation in the airborne and in-situ research studies, data

  7. 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.

  8. Requirements for airborne vector gravimetry

    NASA Technical Reports Server (NTRS)

    Schwarz, K. P.; Colombo, O.; Hein, G.; Knickmeyer, E. T.

    1992-01-01

    The objective of airborne vector gravimetry is the determination of the full gravity disturbance vector along the aircraft trajectory. The paper briefly outlines the concept of this method using a combination of inertial and GPS-satellite data. The accuracy requirements for users in geodesy and solid earth geophysics, oceanography and exploration geophysics are then specified. Using these requirements, accuracy specifications for the GPS subsystem and the INS subsystem are developed. The integration of the subsystems and the problems connected with it are briefly discussed and operational methods are indicated that might reduce some of the stringent accuracy requirements.

  9. 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.

  10. Toolsets for Airborne Data - URS and New Documentation

    Atmospheric Science Data Center

    2015-03-23

    ... airborne field missions, documentation, and EOSDIS User Registration System (URS) authentication. This web application features an intuitive user interface for variable selection across different airborne field studies and ...

  11. Aviation noise effects

    NASA Astrophysics Data System (ADS)

    Newman, J. S.; Beattie, K. R.

    1985-03-01

    This report summarizes the effects of aviation noise in many areas, ranging from human annoyance to impact on real estate values. It also synthesizes the findings of literature on several topics. Included in the literature were many original studies carried out under FAA and other Federal funding over the past two decades. Efforts have been made to present the critical findings and conclusions of pertinent research, providing, when possible, a bottom line conclusion, criterion or perspective. Issues related to aviation noise are highlighted, and current policy is presented. Specific topic addressed include: annoyance; Hearing and hearing loss; noise metrics; human response to noise; speech interference; sleep interference; non-auditory health effects of noise; effects of noise on wild and domesticated animals; low frequency acoustical energy; impulsive noise; time of day weightings; noise contours; land use compatibility; and real estate values. This document is designed for a variety of users, from the individual completely unfamiliar with aviation noise to experts in the field.

  12. Quantum Dot Light Emitting Diode

    SciTech Connect

    Kahen, Keith

    2008-07-31

    The project objective is to create low cost coatable inorganic light emitting diodes, composed of quantum dot emitters and inorganic nanoparticles, which have the potential for efficiencies equivalent to that of LEDs and OLEDs and lifetime, brightness, and environmental stability between that of LEDs and OLEDs. At the end of the project the Recipient shall gain an understanding of the device physics and properties of Quantum-Dot LEDs (QD-LEDs), have reliable and accurate nanocrystal synthesis routines, and have formed green-yellow emitting QD-LEDs with a device efficiency greater than 3 lumens/W, a brightness greater than 400 cd/m{sup 2}, and a device operational lifetime of more than 1000 hours. Thus the aim of the project is to break the current cost-efficiency paradigm by creating novel low cost inorganic LEDs composed of inorganic nanoparticles.

  13. Quantum Dot Light Emitting Diode

    SciTech Connect

    Keith Kahen

    2008-07-31

    The project objective is to create low cost coatable inorganic light emitting diodes, composed of quantum dot emitters and inorganic nanoparticles, which have the potential for efficiencies equivalent to that of LEDs and OLEDs and lifetime, brightness, and environmental stability between that of LEDs and OLEDs. At the end of the project the Recipient shall gain an understanding of the device physics and properties of Quantum-Dot LEDs (QD-LEDs), have reliable and accurate nanocrystal synthesis routines, and have formed green-yellow emitting QD-LEDs with a device efficiency greater than 3 lumens/W, a brightness greater than 400 cd/m2, and a device operational lifetime of more than 1000 hours. Thus the aim of the project is to break the current cost-efficiency paradigm by creating novel low cost inorganic LEDs composed of inorganic nanoparticles.

  14. Meeting Review: Airborne Aerosol Inlet Workshop

    NASA Technical Reports Server (NTRS)

    Baumgardner, Darrel; Huebert, Barry; Wilson, Chuck

    1991-01-01

    Proceedings from the Airborne Aerosol Inlet Workshop are presented. The two central topics of discussion were the role of aerosols in atmospheric processes and the difficulties in characterizing aerosols. The following topics were discussed during the working sessions: airborne observations to date; identification of inlet design issues; inlet modeling needs and directions; objectives for aircraft experiments; and future laboratory and wind tunnel studies.

  15. Airborne Relay-Based Regional Positioning System

    PubMed Central

    Lee, Kyuman; Noh, Hongjun; Lim, Jaesung

    2015-01-01

    Ground-based pseudolite systems have some limitations, such as low vertical accuracy, multipath effects and near-far problems. These problems are not significant in airborne-based pseudolite systems. However, the monitoring of pseudolite positions is required because of the mobility of the platforms on which the pseudolites are mounted, and this causes performance degradation. To address these pseudolite system limitations, we propose an airborne relay-based regional positioning system that consists of a master station, reference stations, airborne relays and a user. In the proposed system, navigation signals are generated from the reference stations located on the ground and are relayed via the airborne relays. Unlike in conventional airborne-based systems, the user in the proposed system sequentially estimates both the locations of airborne relays and his/her own position. Therefore, a delay due to monitoring does not occur, and the accuracy is not affected by the movement of airborne relays. We conducted several simulations to evaluate the performance of the proposed system. Based on the simulation results, we demonstrated that the proposed system guarantees a higher accuracy than airborne-based pseudolite systems, and it is feasible despite the existence of clock offsets among reference stations. PMID:26029953

  16. Airborne Oceanographic Lidar (AOL) (Global Carbon Cycle)

    NASA Technical Reports Server (NTRS)

    2003-01-01

    This bimonthly contractor progress report covers the operation, maintenance and data management of the Airborne Oceanographic Lidar and the Airborne Topographic Mapper. Monthly activities included: mission planning, sensor operation and calibration, data processing, data analysis, network development and maintenance and instrument maintenance engineering and fabrication.

  17. Global Test Range: Toward Airborne Sensor Webs

    NASA Technical Reports Server (NTRS)

    Mace, Thomas H.; Freudinger, Larry; DelFrate John H.

    2008-01-01

    This viewgraph presentation reviews the planned global sensor network that will monitor the Earth's climate, and resources using airborne sensor systems. The vision is an intelligent, affordable Earth Observation System. Global Test Range is a lab developing trustworthy services for airborne instruments - a specialized Internet Service Provider. There is discussion of several current and planned missions.

  18. A Simple Method for Collecting Airborne Pollen

    ERIC Educational Resources Information Center

    Kevan, Peter G.; DiGiovanni, Franco; Ho, Rong H.; Taki, Hisatomo; Ferguson, Kristyn A.; Pawlowski, Agata K.

    2006-01-01

    Pollination is a broad area of study within biology. For many plants, pollen carried by wind is required for successful seed set. Airborne pollen also affects human health. To foster studies of airborne pollen, we introduce a simple device--the "megastigma"--for collecting pollen from the air. This device is flexible, yielding easily obtained data…

  19. 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.

  20. Porous light-emitting compositions

    DOEpatents

    Burrell, Anthony K.; McCleskey, Thomas Mark; Jia, Quanxi; Bauer, Eve; Mueller, Alexander H.

    2012-04-17

    Light-emitting devices are prepared by coating a porous substrate using a polymer-assisted deposition process. Solutions of metal precursor and soluble polymers having binding properties for metal precursor were coated onto porous substrates. The coated substrates were heated at high temperatures under a suitable atmosphere. The result was a substrate with a conformal coating that did not substantially block the pores of the substrate.

  1. Airborne radioactive effluent study at the Savannah River Plant

    SciTech Connect

    Blanchard, R.L.; Broadway, J.A.; Sensintaffar, E.L.; Kirk, W.P.; Kahn, B.; Garrett, A.J.

    1984-07-01

    Under the Clean Air Act, Sections 112 and 122 as amended in 1977, the Office of Radiation Programs (OPR) of the United States Environmental Protection Agency is currently developing standards for radionuclides emitted to the air by several source categories. In order to confirm source-term measurements and pathway calculations for radiation exposures to humans offsite, the ORP performs field studies at selected facilities that emit radionuclides. This report describes the field study conducted at the Savannah River Plant (SRP), a laboratory operated by E.I. du Pont de Nemours and Company for the US Department of Energy. This purpose of the study at ARP was to verify reported airborne releases and resulting radiation doses from the facility. Measurements of radionuclide releases for brief periods were compared with measurements performed by SRP staff on split samples and with annual average releases reported by SRP for the same facilities. The dispersion model used by SRP staff to calculate radiation doses offsite was tested by brief environmental radioactivity measurements performed simultaneously with the release measurements, and by examining radioactivity levels in environmental samples. This report describes in detail all measurements made and data collected during the field study and presents the results obtained. 34 references, 18 figures, 49 tables.

  2. White light-emitting organic electroluminescent devices

    DOEpatents

    Shiang, Joseph John; Duggal, Anil Raj; Parthasarathy, Gautam

    2006-06-20

    A light-emitting device comprises a light-emitting member, which comprises two electrodes, at least two organic electroluminescent ("EL") materials disposed between the electrodes, a charge blocking material disposed between the electrodes, and at least one photoluminescent ("PL") material. The light-emitting member emits electromagnetic ("EM") radiation having a first spectrum in response to a voltage applied across the two electrodes. The PL material absorbs a portion of the EM radiation emitted by the light-emitting member and emits EM radiation having second spectrum different than the first spectrum. Each of the organic EL materials emits EM radiation having a wavelength range selected from the group consisting of blue and red wavelength ranges.

  3. Experimentally increased noise levels change spatial and singing behaviour

    PubMed Central

    McLaughlin, Kirsty Elizabeth; Kunc, Hansjoerg P.

    2013-01-01

    The reasons why animal populations decline in response to anthropogenic noise are still poorly understood. To understand how populations are affected by noise, we must understand how individuals are affected by noise. By modifying the acoustic environment experimentally, we studied the potential relationship between noise levels and both spatial and singing behaviour in the European robin (Erithacus rubecula). We found that with increasing noise levels, males were more likely to move away from the noise source and changed their singing behaviour. Our results provide the first experimental evidence in a free ranging species, that not merely the presence of noise causes changes in behaviour and distribution, but that the level of noise pollution plays a crucial role as well. Our results have important implications for estimating the impact of infrastructure which differs in the level of noise produced. Thus, governmental planning bodies should not only consider the physical effect on the landscape when assessing the impact of new infrastructure, but also the noise levels emitted, which may reduce the loss of suitable habitats available for animals. PMID:23173189

  4. The Effect of Road Traffic Noise on Reaction Time

    PubMed Central

    Alimohammadi, Iraj; Zokaei, Mojtaba; Sandrock, Stephan

    2015-01-01

    Background: Traffic noise is one of the main important sources in urban noise pollution, which causes various physiological and psychological effects that can cause disturbs in performance, sleep disturbances, hearing loss and impact on job performance. This study was conducted to verify the impact of road traffic noise on reaction time in terms of extraversion and sex. Methods: Traffic noise was measured and recorded in 10 arterial streets in Tehran, and then the recorded noise was emitted towards participants in an acoustic room. The participants were 80 (40 cases and 40 controls) students. Personality type was determined by Eysenck Personality Inventory (EPI) questioner. Reaction time before and after exposure to traffic noise was measured. Results: Reaction time before exposure to traffic noise did not differ (P=0.437) significantly between introverts and extraverts. However, it was increased significantly in both groups after exposure to traffic noise (P<0.01). Introvert’s reaction time was more increased than that of extraverts. Conclusion: Traffic noise augmented reaction time of both males and females. This study also revealed that exposure to traffic noise leads to increase in reaction time. PMID:26634199

  5. AIRBORNE, OPTICAL REMOTE SENSING OF METHANE AND ETHANE FOR NATURAL GAS PIPELINE LEAK DETECTION

    SciTech Connect

    Jerry Myers

    2003-05-13

    Ophir Corporation was awarded a contract by the U. S. Department of Energy, National Energy Technology Laboratory under the Project Title ''Airborne, Optical Remote Sensing of Methane and Ethane for Natural Gas Pipeline Leak Detection'' on October 14, 2002. This six-month technical report summarizes the progress for each of the proposed tasks, discusses project concerns, and outlines near-term goals. Ophir has completed a data survey of two major natural gas pipeline companies on the design requirements for an airborne, optical remote sensor. The results of this survey are disclosed in this report. A substantial amount of time was spent on modeling the expected optical signal at the receiver at different absorption wavelengths, and determining the impact of noise sources such as solar background, signal shot noise, and electronic noise on methane and ethane gas detection. Based upon the signal to noise modeling and industry input, Ophir finalized the design requirements for the airborne sensor, and released the critical sensor light source design requirements to qualified vendors. Responses from the vendors indicated that the light source was not commercially available, and will require a research and development effort to produce. Three vendors have responded positively with proposed design solutions. Ophir has decided to conduct short path optical laboratory experiments to verify the existence of methane and absorption at the specified wavelength, prior to proceeding with the light source selection. Techniques to eliminate common mode noise were also evaluated during the laboratory tests. Finally, Ophir has included a summary of the potential concerns for project success and has established future goals.

  6. Biomonitoring of airborne particulate matter emitted from a cement plant and comparison with dispersion modelling results

    NASA Astrophysics Data System (ADS)

    Abril, Gabriela A.; Wannaz, Eduardo D.; Mateos, Ana C.; Pignata, María L.

    2014-01-01

    The influence of a cement plant that incinerates industrial waste on the air quality of a region in the province of Córdoba, Argentina, was assessed by means of biomonitoring studies (effects of immission) and atmospheric dispersion (effects of emission) of PM10 with the application of the ISC3 model (Industrial Source Complex) developed by the USEPA (Environmental Protection Agency). For the biomonitoring studies, samples from the epiphyte plant Tillandsia capillaris Ruíz & Pav. f. capillaris were transplanted to the vicinities of the cement plant in order to determine the physiological damage and heavy metal accumulation (Ca, Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb). For the application of the ISC3 model, point and area sources from the cement plant were considered to obtain average PM10 concentration results from the biomonitoring exposure period. This model permitted it to be determined that the emissions from the cement plant (point and area sources) were confined to the vicinities, without significant dispersion in the study area. This was also observed in the biomonitoring study, which identified Ca, Cd and Pb, pH and electric conductivity (EC) as biomarkers of this cement plant. Vehicular traffic emissions and soil re-suspension could be observed in the biomonitors, giving a more complete scenario. In this study, biomonitoring studies along with the application of atmospheric dispersion models, allowed the atmospheric pollution to be assessed in more detail.

  7. 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.

  8. Geophex Airborne Unmanned Survey System

    SciTech Connect

    Won, I.L.; Keiswetter, D.

    1995-12-31

    Ground-based surveys place personnel at risk due to the proximity of buried unexploded ordnance (UXO) items or by exposure to radioactive materials and hazardous chemicals. The purpose of this effort is to design, construct, and evaluate a portable, remotely-piloted, airborne, geophysical survey system. This non-intrusive system will provide stand-off capability to conduct surveys and detect buried objects, structures, and conditions of interest at hazardous locations. During a survey, the operators remain remote from, but within visual distance of, the site. The sensor system never contacts the Earth, but can be positioned near the ground so that weak geophysical anomalies can be detected. The Geophex Airborne Unmanned Survey System (GAUSS) is designed to detect and locate small-scale anomalies at hazardous sites using magnetic and electromagnetic survey techniques. The system consists of a remotely-piloted, radio-controlled, model helicopter (RCH) with flight computer, light-weight geophysical sensors, an electronic positioning system, a data telemetry system, and a computer base-station. The report describes GAUSS and its test results.

  9. Airborne cw Doppler lidar (ADOLAR)

    NASA Astrophysics Data System (ADS)

    Rahm, Stefan; Werner, Christian; Nagel, E.; Herrmann, H.; Klier, M.; Knott, H. P.; Haering, R.; Wildgruber, J.

    1994-12-01

    During the last 10 years the DLR container LDA (Laser Doppler Anemometer) was used for many wind related measurements in the atmospheric boundary layer. The experience out of this were used to construct an airborne Doppler lidar ADOLAR. Based on the available Doppler lidars it is now proposed to perform a campaign to demonstrate the concept of the spaceborne sensor ALADIN, and to answer some questions concerning the signal quality from clouds, water and land. For the continuous wave CO2 laser, the energy is focused by the telescope into the region of investigation. Some of the radiation is back scattered by small aerosol particles drifting with the wind speed through the sensing volume. The back scattered radiation is collected by the telescope and detected by coherent technique. With the laser Doppler method one gets the radial wind component. To determine the magnitude and direction of the horizontal wind, some form of scanning in azimuth and elevation is required. To keep the airborne system compact, the transceiver optics is directly coupled to a wedge scanner which provides the conical scan with the axis in Nadir direction from the aircraft. The system ADOLAR was tested in 1994. Results of the flight over the lake Ammersee are presented and are compared with the data of the inertial reference system of the aircraft.

  10. Airborne thermography applications in Argentina

    NASA Astrophysics Data System (ADS)

    Castro, Eduardo H.; Selles, Eduardo J.; Costanzo, Marcelo; Franco, Oscar; Diaz, Jose

    2002-03-01

    Forest fires in summer and sheep buried under the snow in winter have become important problems in the south of our country, in the region named Patagonia. We are studying to find a solution by means of an airborne imaging system whose construction we have just finished. It is a 12 channel multispectral airborne scanner system that can be mounted in a Guarani airplane or in a Learjet; the first is a non- pressurized aircraft for flight at low height and the second is a pressurized one for higher flights. The scanner system is briefly described. Their sensors can detect radiation from the ultra violet to the thermal infrared. The images are visualized in real time in a monitor screen and can be stored in the hard disc of the PC for later processing. The use of this scanner for some applications that include the prevention and fighting of forest fires and the study of the possibility of detection of sheep under snow in the Patagonia is now being accomplished. Theoretical and experimental results in fire detection and a theoretical model for studying the possibility of detection of the buried sheep are presented.

  11. Identifying airborne metal particles sources near an optoelectronic and semiconductor industrial park

    NASA Astrophysics Data System (ADS)

    Chen, Ho-Wen; Chen, Wei-Yea; Chang, Cheng-Nan; Chuang, Yen-Hsun; Lin, Yu-Hao

    2016-06-01

    The recently developed Central Taiwan Science Park (CTSP) in central Taiwan is home to an optoelectronic and semiconductor industrial cluster. Therefore, exploring the elemental compositions and size distributions of airborne particles emitted from the CTSP would help to prevent pollution. This study analyzed size-fractionated metal-rich particle samples collected in upwind and downwind areas of CTSP during Jan. and Oct. 2013 by using micro-orifice uniform deposited impactor (MOUDI). Correlation analysis, hierarchical cluster analysis and particle mass-size distribution analysis are performed to identify the source of metal-rich particle near the CTSP. Analyses of elemental compositions and particle size distributions emitted from the CTSP revealed that the CTSP emits some metals (V, As, In Ga, Cd and Cu) in the ultrafine particles (< 1 μm). The statistical analysis combines with the particle mass-size distribution analysis could provide useful source identification information. In airborne particles with the size of 0.32 μm, Ga could be a useful pollution index for optoelectronic and semiconductor emission in the CTSP. Meanwhile, the ratios of As/Ga concentration at the particle size of 0.32 μm demonstrates that humans near the CTSP would be potentially exposed to GaAs ultrafine particles. That is, metals such as Ga and As and other metals that are not regulated in Taiwan are potentially harmful to human health.

  12. Noise reduction techniques in the design of a pneumatic-driven hand held power tool

    NASA Astrophysics Data System (ADS)

    Skinner, Christian M.

    2005-09-01

    Pneumatic-driven hand-held power tools generate noise in the workplace. Current legislation in Europe and the USA aims at protecting workers against noise exposure. In the United States, the Occupational Safety and Health Administration (OSHA) requires that employers create a hearing conservation program if the noise exposure exceeds 85 dB(A). In the European Community under the Directive 2003/10/EC, employers are required to provide hearing protection if the noise exposure within the working environment exceeds 80 dB(A) and must require hearing protection to be worn if the noise exposure exceeds 85 dB(A). This paper examines the sources of noise which contribute to the overall noise from a hand-held power tool. A test plan was developed to identify these individual sources of noise and to determine if structure-borne noise or airborne noise is the dominant source relative to the overall noise level. The measurements were performed per International Standards Organization (ISO) 15744. This paper will describe the methodology used to identify the noise sources and reduce the overall noise of a hand-held power tool.

  13. Thermal Infrared Spectral Imager for Airborne Science Applications

    NASA Technical Reports Server (NTRS)

    Johnson, William R.; Hook, Simon J.; Mouroulis, Pantazis; Wilson, Daniel W.; Gunapala, Sarath D.; Hill, Cory J.; Mumolo, Jason M.; Eng, Bjorn T.

    2009-01-01

    An airborne thermal hyperspectral imager is under development which utilizes the compact Dyson optical configuration and quantum well infrared photo detector (QWIP) focal plane array. The Dyson configuration uses a single monolithic prism-like grating design which allows for a high throughput instrument (F/1.6) with minimal ghosting, stray-light and large swath width. The configuration has the potential to be the optimal imaging spectroscopy solution for lighter-than-air (LTA) vehicles and unmanned aerial vehicles (UAV) due to its small form factor and relatively low power requirements. The planned instrument specifications are discussed as well as design trade-offs. Calibration testing results (noise equivalent temperature difference, spectral linearity and spectral bandwidth) and laboratory emissivity plots from samples are shown using an operational testbed unit which has similar specifications as the final airborne system. Field testing of the testbed unit was performed to acquire plots of apparent emissivity for various known standard minerals (such as quartz). A comparison is made using data from the ASTER spectral library.

  14. Simulation Results for Airborne Precision Spacing along Continuous Descent Arrivals

    NASA Technical Reports Server (NTRS)

    Barmore, Bryan E.; Abbott, Terence S.; Capron, William R.; Baxley, Brian T.

    2008-01-01

    This paper describes the results of a fast-time simulation experiment and a high-fidelity simulator validation with merging streams of aircraft flying Continuous Descent Arrivals through generic airspace to a runway at Dallas-Ft Worth. Aircraft made small speed adjustments based on an airborne-based spacing algorithm, so as to arrive at the threshold exactly at the assigned time interval behind their Traffic-To-Follow. The 40 aircraft were initialized at different altitudes and speeds on one of four different routes, and then merged at different points and altitudes while flying Continuous Descent Arrivals. This merging and spacing using flight deck equipment and procedures to augment or implement Air Traffic Management directives is called Flight Deck-based Merging and Spacing, an important subset of a larger Airborne Precision Spacing functionality. This research indicates that Flight Deck-based Merging and Spacing initiated while at cruise altitude and well prior to the Terminal Radar Approach Control entry can significantly contribute to the delivery of aircraft at a specified interval to the runway threshold with a high degree of accuracy and at a reduced pilot workload. Furthermore, previously documented work has shown that using a Continuous Descent Arrival instead of a traditional step-down descent can save fuel, reduce noise, and reduce emissions. Research into Flight Deck-based Merging and Spacing is a cooperative effort between government and industry partners.

  15. Propagation of Environmental Noise

    ERIC Educational Resources Information Center

    Lyon, R. H.

    1973-01-01

    Solutions for environmental noise pollution lie in systematic study of many basic processes such as reflection, scattering, and spreading. Noise propagation processes should be identified in different situations and assessed for their relative importance. (PS)

  16. Direct Measurement of Atmospheric Ammonia from an Airborne Miniature Chemical Ionization Mass Spectrometer (miniCIMS)

    NASA Astrophysics Data System (ADS)

    Casados, K.; Schill, S.; Freeman, S.; Zoerb, M.; Bertram, T. H.; Lefer, B. L.

    2015-12-01

    Ammonia is emitted into the atmosphere from a variety of sources such as trees, ocean, diary fields, biomass burning, and fuel emissions. Previous studies have investigated the environmental impacts of atmospheric ammonia which can include chemical reactivity, nucleation of fine particulate matter 2.5 (PM 2.5 ), and implications for human health, but its chemical nature and relatively short lifetime make direct measurement of atmospheric ammonia difficult. During the 2015 NASA Student Airborne Research Program (SARP) an airborne miniature Chemical Ionization Mass Spectrometer (miniCIMS) was deployed on the NASA DC-8 flying laboratory in the Southern California region. The spatial and temporal variability of measured atmospheric ammonia concentrations will be discussed.

  17. Core-Noise

    NASA Technical Reports Server (NTRS)

    Hultgren, Lennart S.

    2010-01-01

    This presentation is a technical progress report and near-term outlook for NASA-internal and NASA-sponsored external work on core (combustor and turbine) noise funded by the Fundamental Aeronautics Program Subsonic Fixed Wing (SFW) Project. Sections of the presentation cover: the SFW system level noise metrics for the 2015, 2020, and 2025 timeframes; the emerging importance of core noise and its relevance to the SFW Reduced-Noise-Aircraft Technical Challenge; the current research activities in the core-noise area, with some additional details given about the development of a high-fidelity combustion-noise prediction capability; the need for a core-noise diagnostic capability to generate benchmark data for validation of both high-fidelity work and improved models, as well as testing of future noise-reduction technologies; relevant existing core-noise tests using real engines and auxiliary power units; and examples of possible scenarios for a future diagnostic facility. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The SFW Reduced-Noise-Aircraft Technical Challenge aims to enable concepts and technologies to dramatically reduce the perceived aircraft noise outside of airport boundaries. This reduction of aircraft noise is critical for enabling the anticipated large increase in future air traffic. Noise generated in the jet engine core, by sources such as the compressor, combustor, and turbine, can be a significant contribution to the overall noise signature at low-power conditions, typical of approach flight. At high engine power during takeoff, jet and fan noise have traditionally dominated over core noise. However, current design trends and expected technological advances in engine-cycle design as well as noise-reduction methods are likely to reduce non-core noise even at engine-power points higher than approach. In addition, future low-emission combustor designs could increase

  18. Noise Reduction Techniques

    NASA Astrophysics Data System (ADS)

    Hallas, Tony

    There are two distinct kinds of noise - structural and color. Each requires a specific method of attack to minimize. The great challenge is to reduce the noise without reducing the faint and delicate detail in the image. My most-used and favorite noise suppression is found in Photoshop CS 5 Camera Raw. If I cannot get the desired results with the first choice, I will use Noise Ninja, which has certain advantages in some situations that we will cover.

  19. Noise temperature in graphene at high frequencies

    NASA Astrophysics Data System (ADS)

    Rengel, Raúl; Iglesias, José M.; Pascual, Elena; Martín, María J.

    2016-07-01

    A numerical method for obtaining the frequency-dependent noise temperature in monolayer graphene is presented. From the mobility and diffusion coefficient values provided by Monte Carlo simulation, the noise temperature in graphene is studied up to the THz range, considering also the influence of different substrate types. The influence of the applied electric field is investigated: the noise temperature is found to increase with the applied field, dropping down at high frequencies (in the sub-THz range). The results show that the low-frequency value of the noise temperature in graphene on a substrate tends to be reduced as compared to the case of suspended graphene due to the important effect of remote polar phonon interactions, thus indicating a reduced emitted noise power; however, at very high frequencies the influence of the substrate tends to be significantly reduced, and the differences between the suspended and on-substrate cases tend to be minimized. The values obtained are comparable to those observed in GaAs and semiconductor nitrides.

  20. Clean enough for industry? An airborne geophysical case study

    SciTech Connect

    Nyquist, J.E.; Beard, L.P.

    1996-11-01

    Data from two airborne geophysical surveys of the Department of Energy`s Oak Ridge Reservation (ORR) were extremely valuable in deciding whether a 1000-acre (400 hectare) parcel of the ORR should be leased to the City of Oak Ridge for industrial development. Our findings, based on electromagnetic and magnetic data, were incorporated in the federally mandated Environmental Assessment Statement (EAS), and in general supported claims that this land was never used as a hazardous waste disposal site. We estimated the amount of iron required to produce each anomaly using a simple dipole model. All anomalies with equivalent sources greater than approximately 1000 kg of iron were checked in the field, and the source of all but one identified as either a bridge, reinforced concrete debris, or a similarly benign object. Additionally, some smaller anomalies (equivalent sources of roughly 500 kg) have been checked; thus far, these also have innocuous sources. Airborne video proved invaluable in identifying logging equipment as the source of some of these anomalies. Geologic noise may account for some of the remaining anomalies. Naturally occurring accumulations of magnetic minerals in the soil on the ORR have been shown to produce anomalies which, at a sensor height of 30 in, are comparable to the anomaly produced by about 500 kg of iron. By comparison, the electronic noise of the magnetic gradiometer, 0.01- 0.02 nT/m, is equivalent to only about 50-100 kg of iron at a 30 m sensor height. The electromagnetic data, combined with field mapping of karst structures, provided evidence of a northeast-southwest striking conduit spanning the parcel. The possible existence of a karst conduit led the EAS authors to conclude that this is a {open_quotes}sensitive hydrologic setting.{close_quotes} We conclude that aerial geophysics is an extremely cost-effective, and efficient technique for screening large tracts of land for environmental characterization.

  1. Clean enough for industry? An airborne geophysical case study

    SciTech Connect

    Nyquist, J.E.; Beard, L.P.

    1996-02-01

    Data from two airborne geophysical surveys of the Department of Energy`s Oak Ridge Reservation (ORR) were extremely valuable in deciding whether a 1000-acre (400 hectare) parcel of the ORR should be released to the City of Oak Ridge for industrial development. Our findings, based on electromagnetic and magnetic data, were incorporated in the federally mandated Environmental Assessment Statement (EAS), and in general supported claims that this land was never used as a hazardous waste disposal site. We estimated the amount of iron required to produce each anomaly using a simple dipole model. All anomalies with equivalent sources greater than approximately 1000 kg of iron were checked in the field, and the source of all but one identified as either a bridge, reinforced concrete debris, or a similarly benign object. Additionally, some smaller anomalies (equivalent sources of roughly 500 kg) have been checked; thus far, these also have innocuous sources. Airborne video proved invaluable in identifying logging equipment as the source of some of these anomalies. Geologic noise may account for some of the remaining anomalies. Naturally occurring accumulations of magnetic minerals in the soil on the ORR have been shown to produce anomalies which, at a sensor height of 30 m, are comparable to the anomaly produced by about 500 kg of iron. By comparison, the electronic noise of the magnetic gradiometer, 0.01--0.02 nT/m, is equivalent to only about 50--100 kg of iron at a 30 m sensor height. The electromagnetic data, combined with field mapping of karst structures, provided evidence of a northeast-southwest striking conduit spanning the parcel. The possible existence of a karst conduit led the EAS authors to conclude that this is a ``sensitive hydrologic setting.`` We conclude that aerial geophysics is an extremely cost-effective, and efficient technique for screening large tracts of land for environmental characterization.

  2. Handbook of noise ratings

    NASA Technical Reports Server (NTRS)

    Pearsons, K. S.; Bennett, R. L.

    1974-01-01

    The handbook was compiled to provide information in a concise form, describing the multitude of noise rating schemes. It is hoped that by describing the noise rating methods in a single volume the user will have better access to the definitions, application and calculation procedures of the current noise rating methods.

  3. Characteristics of USB noise

    NASA Technical Reports Server (NTRS)

    Gibson, J. S.; Searle, N.

    1976-01-01

    An extensive series of noise measurements, for a variety of geometric and operational parameters, was made on models of upper surface blowing (USB) powered lift systems. The data obtained were analyzed and the effects and trends of parametric variation defined. The behavior and nature of USB noise and the design of USB systems with low noise characteristics is examined.

  4. Exposure of highway maintenance workers to fine particulate matter and noise

    EPA Science Inventory

    In this study we assessed the mixed exposure of highway maintenance workers to airborne particles, noise and gaseous co-pollutants. The aims were to provide a better understanding of the workers exposure to facilitate the evaluation of short-term effects on cardiovascular health ...

  5. Core Noise - Increasing Importance

    NASA Technical Reports Server (NTRS)

    Hultgren, Lennart S.

    2011-01-01

    This presentation is a technical summary of and outlook for NASA-internal and NASA-sponsored external research on core (combustor and turbine) noise funded by the Fundamental Aeronautics Program Subsonic Fixed Wing (SFW) Project. Sections of the presentation cover: the SFW system-level noise metrics for the 2015, 2020, and 2025 timeframes; turbofan design trends and their aeroacoustic implications; the emerging importance of core noise and its relevance to the SFW Reduced-Perceived-Noise Technical Challenge; and the current research activities in the core-noise area, with additional details given about the development of a high-fidelity combustor-noise prediction capability as well as activities supporting the development of improved reduced-order, physics-based models for combustor-noise prediction. The need for benchmark data for validation of high-fidelity and modeling work and the value of a potential future diagnostic facility for testing of core-noise-reduction concepts are indicated. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The SFW Reduced-Perceived-Noise Technical Challenge aims to develop concepts and technologies to dramatically reduce the perceived aircraft noise outside of airport boundaries. This reduction of aircraft noise is critical to enabling the anticipated large increase in future air traffic. Noise generated in the jet engine core, by sources such as the compressor, combustor, and turbine, can be a significant contribution to the overall noise signature at low-power conditions, typical of approach flight. At high engine power during takeoff, jet and fan noise have traditionally dominated over core noise. However, current design trends and expected technological advances in engine-cycle design as well as noise-reduction methods are likely to reduce non-core noise even at engine-power points higher than approach. In addition, future low-emission combustor

  6. The impact of fireworks on airborne particles

    NASA Astrophysics Data System (ADS)

    Vecchi, Roberta; Bernardoni, Vera; Cricchio, Diana; D'Alessandro, Alessandra; Fermo, Paola; Lucarelli, Franco; Nava, Silvia; Piazzalunga, Andrea; Valli, Gianluigi

    Fireworks are one of the most unusual sources of pollution in atmosphere; although transient, these pollution episodes are responsible for high concentrations of particles (especially metals and organic compounds) and gases. In this paper, results of a study on chemical-physical properties of airborne particles (elements, ions, organic and elemental carbon and particles size distributions) collected during a fireworks episode in Milan (Italy) are reported. Elements typically emitted during pyrotechnic displays increased in 1 h as follows: Sr (120 times), Mg (22 times), Ba (12 times), K (11 times), and Cu (6 times). In our case study, Sr was recognised as the best fireworks tracer because its concentration was very high during the event and lower than, or comparable with, minimum detection limits during other time intervals, suggesting that it was mainly due to pyrotechnic displays. In addition, particles number concentrations increased significantly during the episode (up to 6.7 times in 1 h for the 0.5< d<1 μm size bin). Contributions (e.g. Cu, elemental carbon and nitrogen oxides) to air pollution due to the large traffic volume registered during the same night were also singled out. The original application of Positive Matrix Factorisation and Multiple Linear Regression allowed, as far as we know, here for the first time, the quantification of the fireworks contribution to atmospheric particulate matter (PM) and the resolution of their chemical profile. The contribution of fireworks to the local environment in terms of PM 10 mass, elements and chemical components was assessed with 4-h time resolution. PM 10 mass apportioned by fireworks was up to 33.6 μg m -3 (about 50% of the total PM 10 mass). Major contributors were elemental and organic carbon (2.8 and 8.1 μg m -3, respectively) as well as metals like Mg, K, Sr, Ba, and Cu (0.4, 0.7, 0.07, 0.1, and 0.1 μg m -3, respectively).

  7. Visible light emitting vertical cavity surface emitting lasers

    DOEpatents

    Bryan, R.P.; Olbright, G.R.; Lott, J.A.; Schneider, R.P. Jr.

    1995-06-27

    A vertical cavity surface emitting laser that emits visible radiation is built upon a substrate, then having mirrors, the first mirror on top of the substrate; both sets of mirrors being a distributed Bragg reflector of either dielectrics or other materials which affect the resistivity or of semiconductors, such that the structure within the mirror comprises a plurality of sets, each having a thickness of {lambda}/2n where n is the index of refraction of each of the sets; each of the mirrors adjacent to spacers which are on either side of an optically active bulk or quantum well layer; and the spacers and the optically active layer are from one of the following material systems: In{sub z}(Al{sub y}Ga{sub 1{minus}y}){sub 1{minus}z}P, InAlGaAs, AlGaAs, InGaAs, or AlGaP/GaP, wherein the optically active region having a length equal to m {lambda}/2n{sub eff} where m is an integer and n{sub eff} is the effective index of refraction of the laser cavity, and the spacer layer and one of the mirrors being transmissive to radiation having a wavelength of {lambda}/n, typically within the green to red portion of the visible spectrum. 10 figs.

  8. Visible light emitting vertical cavity surface emitting lasers

    DOEpatents

    Bryan, Robert P.; Olbright, Gregory R.; Lott, James A.; Schneider, Jr., Richard P.

    1995-01-01

    A vertical cavity surface emitting laser that emits visible radiation is built upon a substrate, then having mirrors, the first mirror on top of the substrate; both sets of mirrors being a distributed Bragg reflector of either dielectrics or other materials which affect the resistivity or of semiconductors, such that the structure within the mirror comprises a plurality of sets, each having a thickness of .lambda./2n where n is the index of refraction of each of the sets; each of the mirrors adjacent to spacers which are on either side of an optically active bulk or quantum well layer; and the spacers and the optically active layer are from one of the following material systems: In.sub.z (Al.sub.y Ga.sub.1-y).sub.1-z P, InAlGaAs, AlGaAs, InGaAs, or AlGaP/GaP, wherein the optically active region having a length equal to m .lambda./2n.sub.eff where m is an integer and n.sub.eff is the effective index of refraction of the laser cavity, and the spacer layer and one of the mirrors being transmissive to radiation having a wavelength of .lambda./n, typically within the green to red portion of the visible spectrum.

  9. Global deposition of airborne dioxin.

    PubMed

    Booth, Shawn; Hui, Joe; Alojado, Zoraida; Lam, Vicky; Cheung, William; Zeller, Dirk; Steyn, Douw; Pauly, Daniel

    2013-10-15

    We present a global dioxin model that simulates one year of atmospheric emissions, transport processes, and depositions to the earth's terrestrial and marine habitats. We map starting emission levels for each land area, and we also map the resulting deposits to terrestrial and marine environments. This model confirms that 'hot spots' of deposition are likely to be in northern Europe, eastern North America, and in parts of Asia with the highest marine dioxin depositions being the northeast and northwest Atlantic, western Pacific, northern Indian Ocean and the Mediterranean. It also reveals that approximately 40% of airborne dioxin emissions are deposited to marine environments and that many countries in Africa receive more dioxin than they produce, which results in these countries being disproportionately impacted. Since human exposure to dioxin is largely through diet, this work highlights food producing areas that receive higher atmospheric deposits of dioxin than others.

  10. The Sandia Airborne Computer (SANDAC)

    SciTech Connect

    Nava, E.J.

    1992-06-01

    The Sandia Airborne Computer (SANDAC) is a small, modular, high performance, multiprocessor computer originally designed for aerospace applications. It can use a combination of Motorola 68020 and 68040 based processor modules along with AT&T DSP32C based signal processing modules. The system is designed to use up to 15 processors in almost any combination and a complete system can include up to 20 modules. Depending on the mix of processors, total computational throughput can range from 2.5 to greater than 225 Million Instructions Per Second (MIPS). The system is designed so that processors can access all resources in the machine and the inter-processor communication details are completely transparent to the software. In addition to processors, the system includes input/output, memory, and special function modules. Because of its ease of use, small size, durability, and configuration flexibility, SANDAC has been used on applications ranging from missile navigation, guidance, and control systems to medical imaging systems.

  11. Modis-N airborne simulator

    NASA Technical Reports Server (NTRS)

    Cech, Steven D.

    1992-01-01

    All required work associated with the above referenced contract has been successfully completed at this time. The Modis-N Airborne Simulator has been developed from existing AB184 Wildfire spectrometer parts as well as new detector arrays, optical components, and associated mechanical and electrical hardware. The various instrument components have been integrated into an operational system which has undergone extensive laboratory calibration and testing. The instrument has been delivered to NASA Ames where it will be installed on the NASA ER-2. The following paragraphs detail the specific tasks performed during the contract effort, the results obtained during the integration and testing of the instrument, and the conclusions which can be drawn from this effort.

  12. Optical Johnson noise thermometry

    NASA Technical Reports Server (NTRS)

    Shepard, R. L.; Blalock, T. V.; Maxey, L. C.; Roberts, M. J.; Simpson, M. L.

    1989-01-01

    A concept is being explored that an optical analog of the electrical Johnson noise may be used to measure temperature independently of emissivity. The concept is that a laser beam may be modulated on reflection from a hot surface by interaction of the laser photons with the thermally agitated conduction electrons or the lattice phonons, thereby adding noise to the reflected laser beam. If the reflectance noise can be detected and quantified in a background of other noise in the optical and signal processing systems, the reflectance noise may provide a noncontact measurement of the absolute surface temperature and may be independent of the surface's emissivity.

  13. Infrared sky noise study

    NASA Technical Reports Server (NTRS)

    Westphal, J. A.

    1972-01-01

    The hardware and techniques to measure and compare sky noise at several sites were studied, and a device was developed that would maximize its output and minimize its output for modulation. The instrument and its functions are described. The nature of sky emissions and the fluctuation, gaseous sources of sky noise, and aerosol sources are discussed. It is concluded that sky noise really exists, and the spatial distribution of the sky noise sources are such that observed noise values are linear functions of chopping stroke.

  14. Interpreting Transistor Noise

    NASA Astrophysics Data System (ADS)

    Pospieszalski, M. W.

    2010-10-01

    The simple noise models of field effect and bipolar transistors reviewed in this article are quite useful in engineering practice, as illustrated by measured and modeled results. The exact and approximate expressions for the noise parameters of FETs and bipolar transistors reveal certain common noise properties and some general noise properties of both devices. The usefulness of these expressions in interpreting the dependence of measured noise parameters on frequency, bias, and temperature and, consequently, in checking of consistency of measured data has been demonstrated.

  15. Noise of high-performance aircraft at afterburner

    NASA Astrophysics Data System (ADS)

    Tam, Christopher K. W.; Parrish, Sarah A.

    2015-09-01

    The noise from a high-performance aircraft at afterburner is investigated. The main objective is to determine whether the dominant noise components are the same or similar to those of a hot supersonic laboratory jet. For this purpose, measured noise data from F-22A Raptors are analyzed. It is found, based on both spectral and directivity data, that there is a new dominant noise component in addition to the usual turbulent mixing noise. The characteristic features of the new noise component are identified. Measured data indicates that the new noise component is observed only when the rate of fuel burn of the engine is increased significantly above that of the intermediate power setting. This suggests that the new noise component is combustion related. The possibility that it is indirect combustion noise generated by the passage of hot spots from the afterburner through the nozzle of the jet is investigated. Because flow and temperature data were not measured in the F-22A engine tests, to provide support to the proposition, numerical simulations of indirect combustion noise generation due to the passing of an entropy wave pulse (a hot spot) through a military-style nozzle are carried out. Sound generation is observed at the front and at the back of the pulse. This creates a fast and a slow acoustic wave as the sound radiates out from the nozzle exit. Quantitative estimates of the principal directions of acoustic radiation due to the emitted fast and slow acoustic waves are made. It is found that there are reasonably good agreements with measured data. To estimate the intensity level (IL) of the radiated indirect combustion noise, a time-periodic entropy wave train of 15 percent temperature fluctuation is used as a model of the hot spots coming out of the afterburner. This yields an IL of 175.5 dB. This is a fairly intense noise source, well capable of causing the radiation of the new jet noise component.

  16. Airborne thermography or infrared remote sensing.

    PubMed

    Goillot, C C

    1975-01-01

    Airborne thermography is part of the more general remote sensing activity. The instruments suitable for image display are infrared line scanners. A great deal of interest has developed during the past 10 years in airborne thermal remote sensing and many applications are in progress. Infrared scanners on board a satellite are used for observation of cloud cover; airborne infrared scanners are used for forest fire detection, heat budget of soils, detecting insect attack, diseases, air pollution damage, water stress, salinity stress on vegetation, only to cite some main applications relevant to agronomy. Using this system it has become possible to get a 'picture' of our thermal environment.

  17. Core Noise Reduction

    NASA Technical Reports Server (NTRS)

    Hultgren, Lennart S.

    2011-01-01

    This presentation is a technical summary of and outlook for NASA-internal and NASA-sponsored external research on core (combustor and turbine) noise funded by the Fundamental Aeronautics Program Subsonic Fixed Wing (SFW) Project. Sections of the presentation cover: the SFW system-level noise metrics for the 2015, 2020, and 2025 timeframes; turbofan design trends and their aeroacoustic implications; the emerging importance of core noise and its relevance to the SFW Reduce-Perceived-Noise Technical Challenge; and the current research activities in the core noise area. Recent work1 on the turbine-transmission loss of combustor noise is briefly described, two2,3 new NRA efforts in the core-noise area are outlined, and an effort to develop CMC-based acoustic liners for broadband noise reduction suitable for turbofan-core application is delineated. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The reduction of aircraft noise is critical to enabling the anticipated large increase in future air traffic. The Subsonic Fixed Wing Project's Reduce-Perceived-Noise Technical Challenge aims to develop concepts and technologies to dramatically reduce the perceived aircraft noise outside of airport boundaries.

  18. Toward meaningful noise research.

    PubMed

    Holding, D H; Baker, M A

    1987-10-01

    The present review considers a series of studies of noise conducted in collaboration with Dr. Michel Loeb. This review attempts to provide a theoretical perspective as well as to summarize the most important findings of those studies. The work reviewed shows that noise effects interact with other variables, such that a noise effect on one sex is reversed for the other, and is also reversed at different times of the day. A second experiment confirmed this finding with a different arithmetic task. Further work indicated parallels between noise and fatigue, with aftereffects depending upon both work and noise. The final experiment repeated some of these findings with a different task battery of information processing tasks while showing that noise effects further depend on the meaningfulness of the noise background.

  19. Airborne Measurements of Atmospheric Methane Column Abundance Made Using a Pulsed IPDA Lidar

    NASA Technical Reports Server (NTRS)

    Riris, Haris; Numata, Kenji; Li, Steve; Wu, Stewart; Ramanathan, Anamd; Dawsey, Martha; Mao, Jianping; Kawa, Randolph; Abshire, James B.

    2012-01-01

    We report airborne measurements of the column abundance of atmospheric methane made over an altitude range of 3-11 km using a direct detection IPDA lidar with a pulsed laser emitting at 1651 nm. The laser transmitter was a tunable, seeded optical parametric amplifier (OPA) pumped by a Nd:YAG laser and the receiver used a photomultiplier detector and photon counting electronics. The results follow the expected changes with aircraft altitude and the measured line shapes and optical depths show good agreement with theoretical calculations.

  20. Computerized Mathematical Models of Spray Washout of Airborne Contaminants (Radioactivity) in Containment Vessels.

    2003-05-23

    Version 01 Distribution is restricted to the United States Only. SPIRT predicts the washout of airborne contaminants in containment vessels under postulated loss-of-coolant accident (LOCA) conditions. SPIRT calculates iodine removal constants (lambdas) for post-LOCA containment spray systems. It evaluates the effect of the spectrum of drop sizes emitted by the spray nozzles, the effect of drop coalescence, and the precise solution of the time-dependent diffusion equation. STEAM-67 routines are included for calculating the properties ofmore » steam and water according to the 1967 ASME Steam Tables.« less

  1. Airborne EM for geothermal and hydrogeological mapping

    NASA Astrophysics Data System (ADS)

    Menghini, A.; Manzella, A.; Viezzoli, A.; Montanari, D.; Maggi, S.

    2012-12-01

    Within the "VIGOR" project, aimed at assessing the geothermal potential of four regions in southern Italy, Airborne EM data have been acquired, modeled and interpreted. The system deployed was SkyTEM, a time-domain helicopter electromagnetic system designed for hydrogeophysical, environmental and mineral investigations. The AEM data provide, after data acquisition, analysis, processing, and modeling, a distribution volume of electrical resistivity, spanning an investigation depth from ground surface of few hundred meters, depending on resistivity condition. Resistivity is an important physical parameter for geothermal investigation, since it proved to be very effective in mapping anomalies due to hydrothermal fluid circulation, which usually has high salt content and produces clayey alteration minerals. Since the project required, among other issues, to define geothermal resources at shallow level, it was decided to perform a test with an airborne electromagnetic geophysical survey, to verify the advantages offered by the system in covering large areas in a short time. The geophysical survey was carried out in Sicily, Italy, in late 2011, over two test sites named "Termini" and "Western Sicily". The two areas were chosen on different basis. "Termini" area is covered by extensive geological surveys, and was going to be investigated also by means of electrical tomography in its northern part. Since geological condition of Sicily, even at shallow depth, is very complex, this area provided a good place for defining the resistivity values of the main geological units outcropping in the region. "Termini" survey has been also an occasion to define relations between resistivity distribution, lithological units and thermal conductivity. The "Western Sicily" area cover the main thermal manifestations of western Sicily, and the research target was to establish whether they are characterized by common hydrogeological or tectonic features that could be mapped by resistivity

  2. Core-Noise Research

    NASA Technical Reports Server (NTRS)

    Hultgren, Lennart S.

    2012-01-01

    This presentation is a technical summary of and outlook for NASA-internal and NASA-sponsored external research on core noise funded by the Fundamental Aeronautics Program Subsonic Fixed Wing (SFW) Project. Sections of the presentation cover: the SFW system-level noise metrics for the 2015 (N+1), 2020 (N+2), and 2025 (N+3) timeframes; SFW strategic thrusts and technical challenges; SFW advanced subsystems that are broadly applicable to N+3 vehicle concepts, with an indication where further noise research is needed; the components of core noise (compressor, combustor and turbine noise) and a rationale for NASA's current emphasis on the combustor-noise component; the increase in the relative importance of core noise due to turbofan design trends; the need to understand and mitigate core-noise sources for high-efficiency small gas generators; and the current research activities in the core-noise area, with additional details given about forthcoming updates to NASA's Aircraft Noise Prediction Program (ANOPP) core-noise prediction capabilities, two NRA efforts (Honeywell International, Phoenix, AZ and University of Illinois at Urbana-Champaign, respectively) to improve the understanding of core-noise sources and noise propagation through the engine core, and an effort to develop oxide/oxide ceramic-matrix-composite (CMC) liners for broadband noise attenuation suitable for turbofan-core application. Core noise must be addressed to ensure that the N+3 noise goals are met. Focused, but long-term, core-noise research is carried out to enable the advanced high-efficiency small gas-generator subsystem, common to several N+3 conceptual designs, needed to meet NASA's technical challenges. Intermediate updates to prediction tools are implemented as the understanding of the source structure and engine-internal propagation effects is improved. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The

  3. Influence of noise on chaotic laser dynamics

    SciTech Connect

    Liu, C.; Abarbanel, H.D.I.; Nunes, K.,; Roy, R.; Gills, Z.,; Abarbanel, H.D.I.,; Nunes K.,

    1997-06-01

    The Nd:YAG laser with an intracavity second harmonic generating crystal is a versatile test bed for concepts of nonlinear time series analysis as well as for techniques that have been developed for control of chaotic systems. Quantitative comparisons of experimentally measured time series of the infrared light intensity are made with numerically computed time series from a model derived here from basic principles. These comparisons utilize measures that help to distinguish between low and high dimensional dynamics and thus enhance our understanding of the influence of noise sources on the emitted laser light. {copyright} {ital 1997} {ital The American Physical Society}

  4. Principles for Sampling Airborne Radioactivity from Stacks

    SciTech Connect

    Glissmeyer, John A.

    2010-10-18

    This book chapter describes the special processes involved in sampling the airborne effluents from nuclear faciities. The title of the book is Radioactive Air Sampling Methods. The abstract for this chapter was cleared as PNNL-SA-45941.

  5. Airborne Gamma-Spectrometry in Switzerland

    SciTech Connect

    Butterweck, Gernot; Bucher, Benno; Rybach, Ladislaus

    2008-08-07

    Airborne gamma-spectrometry is able to obtain fast radiological information over large areas. The airborne gamma-spectrometry unit deployed in Switzerland by the Swiss National Emergency Operations Centre (NEOC) consists of a Swiss army Super Puma helicopter equipped with four NaI-Detectors with a total volume of 17 liters, associated electronics and a real-time data evaluation and mapping unit developed by the Swiss Federal Institute of Technology (ETH) and the Paul Scherrer Institut (PSI). The operational readiness of the airborne gamma-spectrometry system is validated in annual exercises of one week duration. Data from 2005 and 2006 exercises are represented in maps of {sup 137}Cs activity concentration for two towns located in southern and western Switzerland. An indicator of man-made radioactivity (MMGC ratio) is demonstrated for an area with four different types of nuclear installations. The intercomparison between airborne gamma-spectrometry and ground measurements showed good agreement between both methods.

  6. SOURCES OF HUMAN EXPOSURE TO AIRBORNE PAH

    EPA Science Inventory

    Personal exposures to airborne particulate polycyclic aromatic hydrocarbons (PAHs) were studied in several populations in the US, Japan, and Czech Republic. Personal exposure monitors, developed for human exposure biomonitoring studies were used to collect fine particles (<_ 1....

  7. Judgments of aircraft noise in a traffic noise background

    NASA Technical Reports Server (NTRS)

    Powell, C. A.; Rice, C. G.

    1975-01-01

    An investigation was conducted to determine subjective response to aircraft noise in different road traffic backgrounds. In addition, two laboratory techniques for presenting the aircraft noise with the background noise were evaluated. For one technique, the background noise was continuous over an entire test session; for the other, the background noise level was changed with each aircraft noise during a session. Subjective response to aircraft noise was found to decrease with increasing background noise level, for a range of typical indoor noise levels. Subjective response was found to be highly correlated with the Noise Pollution Level (NPL) measurement scale.

  8. Comparison of deposited surface area of airborne ultrafine particles generated from two welding processes.

    PubMed

    Gomes, J F; Albuquerque, P C; Miranda, Rosa M; Santos, Telmo G; Vieira, M T

    2012-09-01

    This article describes work performed on the assessment of the levels of airborne ultrafine particles emitted in two welding processes metal-active gas (MAG) of carbon steel and friction-stir welding (FSW) of aluminium in terms of deposited area in alveolar tract of the lung using a nanoparticle surface area monitor analyser. The obtained results showed the dependence from process parameters on emitted ultrafine particles and clearly demonstrated the presence of ultrafine particles, when compared with background levels. The obtained results showed that the process that results on the lower levels of alveolar-deposited surface area is FSW, unlike MAG. Nevertheless, all the tested processes resulted in important doses of ultrafine particles that are to be deposited in the human lung of exposed workers.

  9. Low Noise Amplifier Receivers from Millimeter Wave Atmospheric Remote Sensing

    NASA Technical Reports Server (NTRS)

    Kangaslahti, Pekka; Lim, Boon; Gaier, Todd; Tanner, Alan; Varonen, Mikko; Samoska, Lorene; Brown, Shannon; Lambrigsten, Bjorn; Reising, Steven; Tanabe, Jordan; Montes, Oliver; Dawson, Douglas; Parashare, Chaitali

    2012-01-01

    We currently achieve 3.4 dB noise figure at 183GHz and 2.1 dB noise figure at 90 GHz with our MMIC low noise amplifiers (LNAs) in room temperature. These amplifiers and the receivers we have built using them made it possible to conduct highly accurate airborne measurement campaigns from the Global Hawk unmanned aerial vehicle, develop millimeter wave internally calibrated radiometers for altimeter radar path delay correction, and build prototypes of large arrays of millimeter receivers for a geostationary interferometric sounder. We use the developed millimeter wave receivers to measure temperature and humidity profiles in the atmosphere and in hurricanes as well as to characterize the path delay error in ocean topography altimetry.

  10. An Airborne Infrared Spectrometer for Solar Eclipse Observations

    NASA Astrophysics Data System (ADS)

    Samra, Jenna; DeLuca, Edward E.; Golub, Leon; Cheimets, Peter; Philip, Judge

    2016-05-01

    The airborne infrared spectrometer (AIR-Spec) is an innovative solar spectrometer that will observe the 2017 solar eclipse from the NSF/NCAR High-Performance Instrumented Airborne Platform for Environmental Research (HIAPER). AIR-Spec will image five infrared coronal emission lines to determine whether they may be useful probes of coronal magnetism.The solar magnetic field provides the free energy that controls coronal heating, structure, and dynamics. Energy stored in coronal magnetic fields is released in flares and coronal mass ejections and ultimately drives space weather. Therefore, direct coronal field measurements have significant potential to enhance understanding of coronal dynamics and improve solar forecasting models. Of particular interest are observations of field lines in the transitional region between closed and open flux systems, providing important information on the origin of the slow solar wind.While current instruments routinely observe only the photospheric and chromospheric magnetic fields, AIR-Spec will take a step toward the direct observation of coronal fields by measuring plasma emission in the infrared at high spatial and spectral resolution. During the total solar eclipse of 2017, AIR-Spec will observe five magnetically sensitive coronal emission lines between 1.4 and 4 µm from the HIAPER Gulfstream V at an altitude above 14.9 km. The instrument will measure emission line intensity, width, and Doppler shift, map the spatial distribution of infrared emitting plasma, and search for waves in the emission line velocities.AIR-Spec consists of an optical system (feed telescope, grating spectrometer, and infrared detector) and an image stabilization system, which uses a fast steering mirror to correct the line-of-sight for platform perturbations. To ensure that the instrument meets its research goals, both systems are undergoing extensive performance modeling and testing. These results are shown with reference to the science requirements.

  11. Downscaling of Airborne Wind Energy Systems

    NASA Astrophysics Data System (ADS)

    Fechner, Uwe; Schmehl, Roland

    2016-09-01

    Airborne wind energy systems provide a novel solution to harvest wind energy from altitudes that cannot be reached by wind turbines with a similar nominal generator power. The use of a lightweight but strong tether in place of an expensive tower provides an additional cost advantage, next to the higher capacity factor and much lower total mass. This paper investigates the scaling effects of airborne wind energy systems. The energy yield of airborne wind energy systems, that work in pumping mode of operation is at least ten times higher than the energy yield of conventional solar systems. For airborne wind energy systems the yield is defined per square meter wing area. In this paper the dependency of the energy yield on the nominal generator power for systems in the range of 1 kW to 1 MW is investigated. For the onshore location Cabauw, The Netherlands, it is shown, that a generator of just 1.4 kW nominal power and a total system mass of less than 30 kg has the theoretical potential to harvest energy at only twice the price per kWh of large scale airborne wind energy systems. This would make airborne wind energy systems a very attractive choice for small scale remote and mobile applications as soon as the remaining challenges for commercialization are solved.

  12. Challenges and opportunities of airborne metagenomics.

    PubMed

    Behzad, Hayedeh; Gojobori, Takashi; Mineta, Katsuhiko

    2015-05-06

    Recent metagenomic studies of environments, such as marine and soil, have significantly enhanced our understanding of the diverse microbial communities living in these habitats and their essential roles in sustaining vast ecosystems. The increase in the number of publications related to soil and marine metagenomics is in sharp contrast to those of air, yet airborne microbes are thought to have significant impacts on many aspects of our lives from their potential roles in atmospheric events such as cloud formation, precipitation, and atmospheric chemistry to their major impact on human health. In this review, we will discuss the current progress in airborne metagenomics, with a special focus on exploring the challenges and opportunities of undertaking such studies. The main challenges of conducting metagenomic studies of airborne microbes are as follows: 1) Low density of microorganisms in the air, 2) efficient retrieval of microorganisms from the air, 3) variability in airborne microbial community composition, 4) the lack of standardized protocols and methodologies, and 5) DNA sequencing and bioinformatics-related challenges. Overcoming these challenges could provide the groundwork for comprehensive analysis of airborne microbes and their potential impact on the atmosphere, global climate, and our health. Metagenomic studies offer a unique opportunity to examine viral and bacterial diversity in the air and monitor their spread locally or across the globe, including threats from pathogenic microorganisms. Airborne metagenomic studies could also lead to discoveries of novel genes and metabolic pathways relevant to meteorological and industrial applications, environmental bioremediation, and biogeochemical cycles.

  13. Challenges and Opportunities of Airborne Metagenomics

    PubMed Central

    Behzad, Hayedeh; Gojobori, Takashi; Mineta, Katsuhiko

    2015-01-01

    Recent metagenomic studies of environments, such as marine and soil, have significantly enhanced our understanding of the diverse microbial communities living in these habitats and their essential roles in sustaining vast ecosystems. The increase in the number of publications related to soil and marine metagenomics is in sharp contrast to those of air, yet airborne microbes are thought to have significant impacts on many aspects of our lives from their potential roles in atmospheric events such as cloud formation, precipitation, and atmospheric chemistry to their major impact on human health. In this review, we will discuss the current progress in airborne metagenomics, with a special focus on exploring the challenges and opportunities of undertaking such studies. The main challenges of conducting metagenomic studies of airborne microbes are as follows: 1) Low density of microorganisms in the air, 2) efficient retrieval of microorganisms from the air, 3) variability in airborne microbial community composition, 4) the lack of standardized protocols and methodologies, and 5) DNA sequencing and bioinformatics-related challenges. Overcoming these challenges could provide the groundwork for comprehensive analysis of airborne microbes and their potential impact on the atmosphere, global climate, and our health. Metagenomic studies offer a unique opportunity to examine viral and bacterial diversity in the air and monitor their spread locally or across the globe, including threats from pathogenic microorganisms. Airborne metagenomic studies could also lead to discoveries of novel genes and metabolic pathways relevant to meteorological and industrial applications, environmental bioremediation, and biogeochemical cycles. PMID:25953766

  14. Firefighter noise exposure during training activities and general equipment use.

    PubMed

    Root, Kyle S; Schwennker, Catherine; Autenrieth, Daniel; Sandfort, Delvin R; Lipsey, Tiffany; Brazile, William J

    2013-01-01

    Multiple noise measurements were taken on 6 types of fire station equipment and 15 types of emergency response vehicle-related equipment used by firefighters during routine and emergency operations at 10 fire stations. Five of the six types of fire station equipment, when measured at a distance of one meter and ear level, emitted noise equal to or greater than 85 dBA, including lawn maintenance equipment, snow blowers, compressors, and emergency alarms. Thirteen of 15 types of equipment located on the fire engines emitted noise levels equal to or greater than 85 dBA, including fans, saws, alarms, and extrication equipment. In addition, noise measurements were taken during fire engine operations, including the idling vehicle, vehicle sirens, and water pumps. Results indicated that idling fire-engine noise levels were below 85 dBA; however, during water pump and siren use, noise levels exceeded 85 dBA, in some instances, at different locations around the trucks where firefighters would be stationed during emergency operations. To determine if the duration and use of fire fighting equipment was sufficient to result in overexposures to noise during routine training activities, 93 firefighter personal noise dosimetry samples were taken during 10 firefighter training activities. Two training activities per sampling day were monitored during each sampling event, for a mean exposure time of 70 min per day. The noise dosimetry samples were grouped based on job description to compare noise exposures between the different categories of job tasks commonly associated with fire fighting. The three job categories were interior, exterior, and engineering. Mean personal dosimetry results indicated that the average noise exposure was 78 dBA during the training activities that lasted 70 min on average. There was no significant difference in noise exposure between each of the three job categories. Although firefighters routinely use equipment and emergency response vehicles that

  15. Firefighter noise exposure during training activities and general equipment use.

    PubMed

    Root, Kyle S; Schwennker, Catherine; Autenrieth, Daniel; Sandfort, Delvin R; Lipsey, Tiffany; Brazile, William J

    2013-01-01

    Multiple noise measurements were taken on 6 types of fire station equipment and 15 types of emergency response vehicle-related equipment used by firefighters during routine and emergency operations at 10 fire stations. Five of the six types of fire station equipment, when measured at a distance of one meter and ear level, emitted noise equal to or greater than 85 dBA, including lawn maintenance equipment, snow blowers, compressors, and emergency alarms. Thirteen of 15 types of equipment located on the fire engines emitted noise levels equal to or greater than 85 dBA, including fans, saws, alarms, and extrication equipment. In addition, noise measurements were taken during fire engine operations, including the idling vehicle, vehicle sirens, and water pumps. Results indicated that idling fire-engine noise levels were below 85 dBA; however, during water pump and siren use, noise levels exceeded 85 dBA, in some instances, at different locations around the trucks where firefighters would be stationed during emergency operations. To determine if the duration and use of fire fighting equipment was sufficient to result in overexposures to noise during routine training activities, 93 firefighter personal noise dosimetry samples were taken during 10 firefighter training activities. Two training activities per sampling day were monitored during each sampling event, for a mean exposure time of 70 min per day. The noise dosimetry samples were grouped based on job description to compare noise exposures between the different categories of job tasks commonly associated with fire fighting. The three job categories were interior, exterior, and engineering. Mean personal dosimetry results indicated that the average noise exposure was 78 dBA during the training activities that lasted 70 min on average. There was no significant difference in noise exposure between each of the three job categories. Although firefighters routinely use equipment and emergency response vehicles that

  16. Surface-emitting fiber lasers

    NASA Astrophysics Data System (ADS)

    Shapira, Ofer; Kuriki, Ken; Orf, Nicholas D.; Abouraddy, Ayman F.; Benoit, Gilles; Viens, Jean F.; Rodriguez, Alejandro; Ibanescu, Mihai; Joannopoulos, John D.; Fink, Yoel; Brewster, Megan M.

    2006-05-01

    All fiber lasers to date emit radiation only along the fiber axis. Here a fiber that exhibits laser emission that is radially directed from its circumferential surface is demonstrated. A unique and controlled azimuthally anisotropic optical wave front results from the interplay between a cylindrical photonic bandgap fiber resonator, anisotropic organic dye gain, and a linearly polarized axial pump. Low threshold (86nJ) lasing at nine different wavelengths is demonstrated throughout the visible and near-infrared spectra. We also report the experimental realization of unprecedented layer thicknesses of 29.5 nm maintained throughout meter-long fibers. Such a device may have interesting medical applications ranging from photodynamic therapy to in vivo molecular imaging, as well as textile fabric displays.

  17. Poultry Plant Noise Control

    NASA Technical Reports Server (NTRS)

    1982-01-01

    A demonstration conducted last winter at the Tip Top Poultry Plant intended to show poultry plant managers from all over the U.S. potential solutions to the problem of plant noise. Plastic covers used over sound absorbing materials need to meet cleanability requirements, high- pressure water cleaning and other harsh maintenance procedures peculiar to the poultry processing industry. For the demonstration, Fiber Flex, Inc. manufactured and donated 750 noise panels; Owens-Corning Fiberglas Corporation donated the fiberglas cores; and the cover material was purchased from Howe and Bainbridge. The Engineering Experiment Station (EES) conducted before and after noise surveys and is evaluating the effect of noise reduction on turnover and productivity in the demonstration plant. EES plans to conduct a noise abatement workshop and update a handbook to help poultry processors with noise problems. EES study and demonstration may be applicable to other food processing plants where similar sanitary constraints exist.

  18. Luminescence conversion of blue light emitting diodes

    NASA Astrophysics Data System (ADS)

    Schlotter, P.; Schmidt, R.; Schneider, J.

    Using blue-emitting GaN/6HSiC chips as primary light sources, we have fabricated green, yellow, red and white emitting LEDs. The generation of mixed colors, as turquoise and magenta is also demonstrated. The underlying physical principle is that of luminescence down-conversion (Stokes shift), as typical for organic luminescent dye molecules. A white emitting LED, using an inorganic converter, Y3Al5O12:Ce3+( ), has also been realized.

  19. Airborne Interferometry using GNSS Reflections for Surface Level Estimation

    NASA Astrophysics Data System (ADS)

    Semmling, Maximilian; Beyerle, Georg; Schön, Steffen; Stosius, Ralf; Gerber, Thomas; Beckheinrich, Jamila; Markgraf, Markus; Ge, Maorong; Wickert, Jens

    2013-04-01

    The interferometric use of GNSS reflections for ocean altimetry can fill the gap in coverage of ocean observations. Today radar altimeters are used for large scale ocean observations to monitor e.g. global sea level change or circulation processes like El Niño. Spacial and temporal resolution of a single radar altimeter, however, is insufficient to observe mesoscale ocean phenomena like large oceanic eddies that are important indicators of climate change. The high coverage expected for a spaceborne altimeter based on GNSS reflections stimulated investigations on according interferometric methods. Several airborne experiments have been conducted using code observations. Carrier observations have a better precision but are severely affected by noise and have mostly been used in ground-based experiments. A new interferometric approach is presented using carrier observations for airborne application. Implementing a spectral retrieval noise reduction is achieved. A flight experiment was conducted with a Zeppelin airship on 2010/10/12 over Lake Constance at the border between Austria, Germany and Switzerland. The lake surface with an area of 536km2 is suitable for altimetric study as its decimeter range Geoid undulations are well-known. Three GNSS receiver were installed on the airship. A Javad Delta receiver recording direct signals for navigation. The DLR G-REX receiver recording reflected signals for scatterometry and the GORS (GNSS Occultation Reflectometry Scatterometry) receiver recording direct and reflected signals for interferometry. The airship's trajectory is determined from navigation data with a precision better than 10cm using regional augmentation. This presentation focuses on the interferometric analysis of GORS observations. Ray tracing calculations are used to model the difference of direct and reflected signals' path. Spectral retrieval is applied to determine Doppler residuals of modelled path difference and interferometric observations. Lake level

  20. Blue whales respond to anthropogenic noise.

    PubMed

    Melcón, Mariana L; Cummins, Amanda J; Kerosky, Sara M; Roche, Lauren K; Wiggins, Sean M; Hildebrand, John A

    2012-01-01

    Anthropogenic noise may significantly impact exposed marine mammals. This work studied the vocalization response of endangered blue whales to anthropogenic noise sources in the mid-frequency range using passive acoustic monitoring in the Southern California Bight. Blue whales were less likely to produce calls when mid-frequency active sonar was present. This reduction was more pronounced when the sonar source was closer to the animal, at higher sound levels. The animals were equally likely to stop calling at any time of day, showing no diel pattern in their sensitivity to sonar. Conversely, the likelihood of whales emitting calls increased when ship sounds were nearby. Whales did not show a differential response to ship noise as a function of the time of the day either. These results demonstrate that anthropogenic noise, even at frequencies well above the blue whales' sound production range, has a strong probability of eliciting changes in vocal behavior. The long-term implications of disruption in call production to blue whale foraging and other behaviors are currently not well understood. PMID:22393434

  1. Blue whales respond to anthropogenic noise.

    PubMed

    Melcón, Mariana L; Cummins, Amanda J; Kerosky, Sara M; Roche, Lauren K; Wiggins, Sean M; Hildebrand, John A

    2012-01-01

    Anthropogenic noise may significantly impact exposed marine mammals. This work studied the vocalization response of endangered blue whales to anthropogenic noise sources in the mid-frequency range using passive acoustic monitoring in the Southern California Bight. Blue whales were less likely to produce calls when mid-frequency active sonar was present. This reduction was more pronounced when the sonar source was closer to the animal, at higher sound levels. The animals were equally likely to stop calling at any time of day, showing no diel pattern in their sensitivity to sonar. Conversely, the likelihood of whales emitting calls increased when ship sounds were nearby. Whales did not show a differential response to ship noise as a function of the time of the day either. These results demonstrate that anthropogenic noise, even at frequencies well above the blue whales' sound production range, has a strong probability of eliciting changes in vocal behavior. The long-term implications of disruption in call production to blue whale foraging and other behaviors are currently not well understood.

  2. 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.

  3. A Refined Algorithm On The Estimation Of Residual Motion Errors In Airborne SAR Images

    NASA Astrophysics Data System (ADS)

    Zhong, Xuelian; Xiang, Maosheng; Yue, Huanyin; Guo, Huadong

    2010-10-01

    Due to the lack of accuracy in the navigation system, residual motion errors (RMEs) frequently appear in the airborne SAR image. For very high resolution SAR imaging and repeat-pass SAR interferometry, the residual motion errors must be estimated and compensated. We have proposed a new algorithm before to estimate the residual motion errors for an individual SAR image. It exploits point-like targets distributed along the azimuth direction, and not only corrects the phase, but also improves the azimuth focusing. But the required point targets are selected by hand, which is time- and labor-consuming. In addition, the algorithm is sensitive to noises. In this paper, a refined algorithm is proposed aiming at these two shortcomings. With real X-band airborne SAR data, the feasibility and accuracy of the refined algorithm are demonstrated.

  4. 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.

  5. Noise in biological circuits

    SciTech Connect

    Simpson, Michael L; Allen, Michael S.; Cox, Chris D.; Dar, Roy D.; Karig, David K; McCollum, James M.; Cooke, John F

    2009-01-01

    Noise biology focuses on the sources, processing, and biological consequences of the inherent stochastic fluctuations in molecular transitions or interactions that control cellular behavior. These fluctuations are especially pronounced in small systems where the magnitudes of the fluctuations approach or exceed the mean value of the molecular population. Noise biology is an essential component of nanomedicine where the communication of information is across a boundary that separates small synthetic and biological systems that are bound by their size to reside in environments of large fluctuations. Here we review the fundamentals of the computational, analytical, and experimental approaches to noise biology. We review results that show that the competition between the benefits of low noise and those of low population has resulted in the evolution of genetic system architectures that produce an uneven distribution of stochasticity across the molecular components of cells and, in some cases, use noise to drive biological function. We review the exact and approximate approaches to gene circuit noise analysis and simulation, and reviewmany of the key experimental results obtained using flow cytometry and time-lapse fluorescent microscopy. In addition, we consider the probative value of noise with a discussion of using measured noise properties to elucidate the structure and function of the underlying gene circuit. We conclude with a discussion of the frontiers of and significant future challenges for noise biology.

  6. Landing gear noise attenuation

    NASA Technical Reports Server (NTRS)

    Moe, Jeffrey W. (Inventor); Whitmire, Julia (Inventor); Kwan, Hwa-Wan (Inventor); Abeysinghe, Amal (Inventor)

    2011-01-01

    A landing gear noise attenuator mitigates noise generated by airframe deployable landing gear. The noise attenuator can have a first position when the landing gear is in its deployed or down position, and a second position when the landing gear is in its up or stowed position. The noise attenuator may be an inflatable fairing that does not compromise limited space constraints associated with landing gear retraction and stowage. A truck fairing mounted under a truck beam can have a compliant edge to allow for non-destructive impingement of a deflected fire during certain conditions.

  7. 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

    -resolution airborne nighttime TIR imaging. Most of the thermal radiance contrast in the Landsat 8 TIR image is due to slope, surface cover type, and albedo, but there are some very subtle variations in thermally emitted radiance that are spatially coincident with the thermally anomalous areas identified with the airborne data.

  8. Visualizing Airborne and Satellite Imagery

    NASA Technical Reports Server (NTRS)

    Bierwirth, Victoria A.

    2011-01-01

    Remote sensing is a process able to provide information about Earth to better understand Earth's processes and assist in monitoring Earth's resources. The Cloud Absorption Radiometer (CAR) is one remote sensing instrument dedicated to the cause of collecting data on anthropogenic influences on Earth as well as assisting scientists in understanding land-surface and atmospheric interactions. Landsat is a satellite program dedicated to collecting repetitive coverage of the continental Earth surfaces in seven regions of the electromagnetic spectrum. Combining these two aircraft and satellite remote sensing instruments will provide a detailed and comprehensive data collection able to provide influential information and improve predictions of changes in the future. This project acquired, interpreted, and created composite images from satellite data acquired from Landsat 4-5 Thematic Mapper (TM) and Landsat 7 Enhanced Thematic Mapper plus (ETM+). Landsat images were processed for areas covered by CAR during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCT AS), Cloud and Land Surface Interaction Campaign (CLASIC), Intercontinental Chemical Transport Experiment-Phase B (INTEXB), and Southern African Regional Science Initiative (SAFARI) 2000 missions. The acquisition of Landsat data will provide supplemental information to assist in visualizing and interpreting airborne and satellite imagery.

  9. Medicinal smoke reduces airborne bacteria.

    PubMed

    Nautiyal, Chandra Shekhar; Chauhan, Puneet Singh; Nene, Yeshwant Laxman

    2007-12-01

    This study represents a comprehensive analysis and scientific validation of our ancient knowledge about the effect of ethnopharmacological aspects of natural products' smoke for therapy and health care on airborne bacterial composition and dynamics, using the Biolog microplate panels and Microlog database. We have observed that 1h treatment of medicinal smoke emanated by burning wood and a mixture of odoriferous and medicinal herbs (havan sámagri=material used in oblation to fire all over India), on aerial bacterial population caused over 94% reduction of bacterial counts by 60 min and the ability of the smoke to purify or disinfect the air and to make the environment cleaner was maintained up to 24h in the closed room. Absence of pathogenic bacteria Corynebacterium urealyticum, Curtobacterium flaccumfaciens, Enterobacter aerogenes (Klebsiella mobilis), Kocuria rosea, Pseudomonas syringae pv. persicae, Staphylococcus lentus, and Xanthomonas campestris pv. tardicrescens in the open room even after 30 days is indicative of the bactericidal potential of the medicinal smoke treatment. We have demonstrated that using medicinal smoke it is possible to completely eliminate diverse plant and human pathogenic bacteria of the air within confined space. PMID:17913417

  10. Performance Basis for Airborne Separation

    NASA Technical Reports Server (NTRS)

    Wing, David J.

    2008-01-01

    Emerging applications of Airborne Separation Assistance System (ASAS) technologies make possible new and powerful methods in Air Traffic Management (ATM) that may significantly improve the system-level performance of operations in the future ATM system. These applications typically involve the aircraft managing certain components of its Four Dimensional (4D) trajectory within the degrees of freedom defined by a set of operational constraints negotiated with the Air Navigation Service Provider. It is hypothesized that reliable individual performance by many aircraft will translate into higher total system-level performance. To actually realize this improvement, the new capabilities must be attracted to high demand and complexity regions where high ATM performance is critical. Operational approval for use in such environments will require participating aircraft to be certified to rigorous and appropriate performance standards. Currently, no formal basis exists for defining these standards. This paper provides a context for defining the performance basis for 4D-ASAS operations. The trajectory constraints to be met by the aircraft are defined, categorized, and assessed for performance requirements. A proposed extension of the existing Required Navigation Performance (RNP) construct into a dynamic standard (Dynamic RNP) is outlined. Sample data is presented from an ongoing high-fidelity batch simulation series that is characterizing the performance of an advanced 4D-ASAS application. Data of this type will contribute to the evaluation and validation of the proposed performance basis.

  11. 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 ...

  12. Fouling in your own nest: vessel noise increases biofouling.

    PubMed

    Stanley, Jenni A; Wilkens, Serena L; Jeffs, Andrew G

    2014-01-01

    Globally billions of dollars are spent each year on attempting to reduce marine biofouling on commercial vessels, largely because it results in higher fuel costs due to increased hydrodynamic drag. Biofouling has been long assumed to be primarily due to the availability of vacant space on the surface of the hull. Here, it is shown that the addition of the noise emitted through a vessel's hull in port increases the settlement and growth of biofouling organisms within four weeks of clean surfaces being placed in the sea. More than twice as many bryozoans, oysters, calcareous tube worms and barnacles settled and established on surfaces with vessel noise compared to those without. Likewise, individuals from three species grew significantly larger in size in the presence of vessel noise. The results demonstrate that vessel noise in port is promoting biofouling on hulls and that underwater sound plays a much wider ecological role in the marine environment than was previously considered possible.

  13. Sounds and Noises. A Position Paper on Noise Pollution.

    ERIC Educational Resources Information Center

    Chapman, Thomas L.

    This position paper focuses on noise pollution and the problems and solutions associated with this form of pollution. The paper is divided into the following five sections: Noise and the Ear, Noise Measurement, III Effects of Noise, Acoustics and Action, and Programs and Activities. The first section identifies noise and sound, the beginnings of…

  14. Proceedings of Noise-con 81: Applied noise control technology

    SciTech Connect

    Royster, L.H.; Hart, F.D.; Stewart, N.D.

    1981-01-01

    The conference was divided into sessions covering noise control regulations and benefits; noise source identification; barriers and enclosures; mufflers; hearing protection devices; textile and fibre industries; metal fabrication industry; transportation and aircraft noise control; punch-press noise control and miscellaneous topics; woodworking industry; tobacco and packaging industries; community noise; and applications of damping materials. One paper has been abstracted separately.

  15. NASA's Coastal and Ocean Airborne Science Testbed

    NASA Astrophysics Data System (ADS)

    Guild, L. S.; Dungan, J. L.; Edwards, M.; Russell, P. B.; Morrow, J. H.; Hooker, S.; Myers, J.; Kudela, R. M.; Dunagan, S.; Soulage, M.; Ellis, T.; Clinton, N. E.; Lobitz, B.; Martin, K.; Zell, P.; Berthold, R. W.; Smith, C.; Andrew, D.; Gore, W.; Torres, J.

    2011-12-01

    The Coastal and Ocean Airborne Science Testbed (COAST) Project is a NASA Earth-science flight mission that will advance coastal ecosystems research by providing a unique airborne payload optimized for remote sensing in the optically complex coastal zone. Teaming NASA Ames scientists and engineers with Biospherical Instruments, Inc. (San Diego) and UC Santa Cruz, the airborne COAST instrument suite combines a customized imaging spectrometer, sunphotometer system, and a new bio-optical radiometer package to obtain ocean/coastal/atmosphere data simultaneously in flight for the first time. The imaging spectrometer (Headwall) is optimized in the blue region of the spectrum to emphasize remote sensing of marine and freshwater ecosystems. Simultaneous measurements supporting empirical atmospheric correction of image data will be accomplished using the Ames Airborne Tracking Sunphotometer (AATS-14). Based on optical detectors called microradiometers, the NASA Ocean Biology and Biogeochemistry Calibration and Validation (cal/val) Office team has deployed advanced commercial off-the-shelf instrumentation that provides in situ measurements of the apparent optical properties at the land/ocean boundary including optically shallow aquatic ecosystems (e.g., lakes, estuaries, coral reefs). A complimentary microradiometer instrument package (Biospherical Instruments, Inc.), optimized for use above water, will be flown for the first time with the airborne instrument suite. Details of the October 2011 COAST airborne mission over Monterey Bay demonstrating this new airborne instrument suite capability will be presented, with associated preliminary data on coastal ocean color products, coincident spatial and temporal data on aerosol optical depth and water vapor column content, as well as derived exact water-leaving radiances.

  16. Synthesis of information on the effects of noise and disturbance on major haulout concentrations of Bering Sea pinnipeds. Final report

    SciTech Connect

    Johnson, S.R.; Burns, J.J.; Malme, C.I.; Davis, R.A.

    1989-02-17

    The study investigated the use of terrestrial haulout sites in the eastern Bering Sea by four species of pennipeds, northern fur seal, northern sea lion, harbor seal and pacific walrus. Historical information on the use of each site was summarized. Available information on the effects of airborne and waterborne noise, and human disturbance (from stationary and moving sources) was reviewed. The authors also conducted a detailed analysis of the acoustic environment of eight haulout sites that were representative of others used by each of the four species studied. The analyses included investigations of (1) characteristics airborne and underwater ambient noise, (2) characteristics of industrial noise sources, including aircraft, small boats, fishing trawlers and commercial cargo traffic, and (3) sound transmission loss in air, water, and through the air-water surface. As a means to evaluate the potential vulnerability of each haulout site to noise and disturbance, a quantitative rating system (IPSI) whereby an index of sensitivity was assigned to each site.

  17. Real-time remote detection and measurement for airborne imaging spectroscopy: a case study with methane

    NASA Astrophysics Data System (ADS)

    Thompson, D. R.; Leifer, I.; Bovensmann, H.; Eastwood, M.; Fladeland, M.; Frankenberg, C.; Gerilowski, K.; Green, R. O.; Kratwurst, S.; Krings, T.; Luna, B.; Thorpe, A. K.

    2015-10-01

    Localized anthropogenic sources of atmospheric CH4 are highly uncertain and temporally variable. Airborne remote measurement is an effective method to detect and quantify these emissions. In a campaign context, the science yield can be dramatically increased by real-time retrievals that allow operators to coordinate multiple measurements of the most active areas. This can improve science outcomes for both single- and multiple-platform missions. We describe a case study of the NASA/ESA CO2 and MEthane eXperiment (COMEX) campaign in California during June and August/September 2014. COMEX was a multi-platform campaign to measure CH4 plumes released from anthropogenic sources including oil and gas infrastructure. We discuss principles for real-time spectral signature detection and measurement, and report performance on the NASA Next Generation Airborne Visible Infrared Spectrometer (AVIRIS-NG). AVIRIS-NG successfully detected CH4 plumes in real-time at Gb s-1 data rates, characterizing fugitive releases in concert with other in situ and remote instruments. The teams used these real-time CH4 detections to coordinate measurements across multiple platforms, including airborne in situ, airborne non-imaging remote sensing, and ground-based in situ instruments. To our knowledge this is the first reported use of real-time trace-gas signature detection in an airborne science campaign, and presages many future applications. Post-analysis demonstrates matched filter methods providing noise-equivalent (1σ) detection sensitivity for 1.0 % CH4 column enhancements equal to 141 ppm m.

  18. CFD simulation of pulsation noise in a small centrifugal compressor with volute and resonance tube

    NASA Astrophysics Data System (ADS)

    Wakaki, Daich; Sakuka, Yuta; Inokuchi, Yuzo; Ueda, Kosuke; Yamasaki, Nobuhiko; Yamagata, Akihiro

    2015-02-01

    The rotational frequency tone noise emitted from the automobile turbocharger is called the pulsation noise. The cause of the pulsation noise is not fully understood, but is considered to be due to some manufacturing errors, which is called the mistuning. The effects of the mistuning of the impeller blade on the noise field inside the flow passage of the compressor are numerically investigated. Here, the flow passage includes the volute and duct located downstream of the compressor impeller. Our numerical approach is found to successfully capture the wavelength of the pulsation noise at given rotational speeds by the comparison with the experiments. One of the significant findings is that the noise field of the pulsation noise in the duct is highly one-dimensional although the flow fields are highly three-dimensional.

  19. Noise monitoring and modeling on four lanning of national highways corridor.

    PubMed

    Devi, P Shiyamala; Rosaline, G Vimala

    2012-10-01

    Noise emitted from traffic contributes to about 55% of total noise pollution in India. This paper is an effort of a research conducted to quantify and analyze the traffic noise emissions along the Salem-Namakkal NH 7 corridor with an ultimate objective of setting up a traffic noise model based on the traffic noise conditions of Indian cities. Noise levels and other variables have been measured in 15 locations to develop a statistical regression model based on A-weighted equivalent noise level for Indian road conditions. The ambient noise levels recorded represent the higher noise levels prevailing along the NH 7 corridor. The Receptor Oriented Technique adopted proves to be helpful in characterizing the ambient noise levels along the study area. The newly developed road traffic noise model can be effectively used as a decision support tool for predicting equivalent noise levels in the cities of India. The present analysis also reveals that the magnitude of noise levels has an increasing trend due to the increased traffic flow and presents the attention needed for minimization. The mitigation measures and the future evaluations are discussed.

  20. Signal-Induced Noise Effects in a Photon Counting System for Stratospheric Ozone Measurement

    NASA Technical Reports Server (NTRS)

    Harper, David B.; DeYoung, Russell J.

    1998-01-01

    A significant source of error in making atmospheric differential absorption lidar ozone measurements is the saturation of the photomultiplier tube by the strong, near field light return. Some time after the near field light signal is gone, the photomultiplier tube gate is opened and a noise signal, called signal-induced noise, is observed. Research reported here gives experimental results from measurement of photomultiplier signal-induced noise. Results show that signal-induced noise has several decaying exponential signals, suggesting that electrons are slowly emitted from different surfaces internal to the photomultiplier tube.

  1. Sounding Off about Noise

    ERIC Educational Resources Information Center

    Crumpton, Michael A.

    2005-01-01

    Noise in a community college library can be part of the nature of the environment. It can also become a huge distraction for those who see the library as their sanctuary for quiet study and review of resources. This article describes the steps that should be taken by library staff in order to be proactive about noise and the library environment,…

  2. Noise Pollution, Teachers' Edition.

    ERIC Educational Resources Information Center

    O'Donnell, Patrick A.; Lavaroni, Charles W.

    One of three in a series about pollution, this teacher's guide for a unit on noise pollution is designed for use in junior high school grades. It offers suggestions for extending the information and activities contained in the textual material for students. Chapter 1 discusses the problem of noise pollution and involves students in processes of…

  3. Predicted airframe noise levels

    NASA Technical Reports Server (NTRS)

    Raney, J. P.

    1980-01-01

    Calculated values of airframe noise levels corresponding to FAA noise certification conditions for six aircraft are presented. The aircraft are: DC-9-30; Boeing 727-200; A300-B2 Airbus; Lockheed L-1011; DC-10-10; and Boeing 747-200B. The prediction methodology employed is described and discussed.

  4. Speech communications in noise

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The physical characteristics of speech, the methods of speech masking measurement, and the effects of noise on speech communication are investigated. Topics include the speech signal and intelligibility, the effects of noise on intelligibility, the articulation index, and various devices for evaluating speech systems.

  5. Noise in miniature microphones.

    PubMed

    Thompson, Stephen C; LoPresti, Janice L; Ring, Eugene M; Nepomuceno, Henry G; Beard, John J; Ballad, William J; Carlson, Elmer V

    2002-02-01

    The internal noise spectrum in miniature electret microphones of the type used in the manufacture of hearing aids is measured. An analogous circuit model of the microphone is empirically fit to the measured data and used to determine the important sources of noise within the microphone. The dominant noise source is found to depend on the frequency. Below 40 Hz and above 9 kHz, the dominant source is electrical noise from the amplifier circuit needed to buffer the electrical signal from the microphone diaphragm. Between approximately 40 Hz and 1 kHz, the dominant source is thermal noise originating in the acoustic flow resistance of the small hole pierced in the diaphragm to equalize barometric pressure. Between approximately 1 kHz and 9 kHz, the noise originates in the acoustic flow resistances of sound entering the microphone and propagating to the diaphragm. To further reduce the microphone internal noise in the audio band requires attacking these sources. A prototype microphone having reduced acoustical noise is measured and discussed. PMID:11863188

  6. Noise in miniature microphones

    NASA Astrophysics Data System (ADS)

    Thompson, Stephen C.; Lopresti, Janice L.; Ring, Eugene M.; Nepomuceno, Henry G.; Beard, John J.; Ballad, William J.; Carlson, Elmer V.

    2002-02-01

    The internal noise spectrum in miniature electret microphones of the type used in the manufacture of hearing aids is measured. An analogous circuit model of the microphone is empirically fit to the measured data and used to determine the important sources of noise within the microphone. The dominant noise source is found to depend on the frequency. Below 40 Hz and above 9 kHz, the dominant source is electrical noise from the amplifier circuit needed to buffer the electrical signal from the microphone diaphragm. Between approximately 40 Hz and 1 kHz, the dominant source is thermal noise originating in the acoustic flow resistance of the small hole pierced in the diaphragm to equalize barometric pressure. Between approximately 1 kHz and 9 kHz, the noise originates in the acoustic flow resistances of sound entering the microphone and propagating to the diaphragm. To further reduce the microphone internal noise in the audio band requires attacking these sources. A prototype microphone having reduced acoustical noise is measured and discussed.

  7. Jet Noise Suppression

    NASA Technical Reports Server (NTRS)

    Gliebe, P. R.; Brausch, J. F.; Majjigi, R. K.; Lee, R.

    1991-01-01

    The objectives of this chapter are to review and summarize the jet noise suppression technology, to provide a physical and theoretical model to explain the measured jet noise suppression characteristics of different concepts, and to provide a set of guidelines for evolving jet noise suppression designs. The underlying principle for all jet noise suppression devices is to enhance rapid mixing (i.e., diffusion) of the jet plume by geometric and aerothermodynamic means. In the case of supersonic jets, the shock-cell broadband noise reduction is effectively accomplished by the elimination or mitigation of the shock-cell structure. So far, the diffusion concepts have predominantly concentrated on jet momentum and energy (kinetic and thermal) diffusion, in that order, and have yielded better noise reduction than the simple conical nozzles. A critical technology issue that needs resolution is the effect of flight on the noise suppression potential of mechanical suppressor nozzles. A more thorough investigation of this mechanism is necessary for the successful development and design of an acceptable noise suppression device for future high-speed civil transports.

  8. Noise: The Ignored Contaminant

    ERIC Educational Resources Information Center

    Miller, Maurice H.

    1977-01-01

    Noise is the single most omnipresent noxious contaminant in the American environment, yet little attention has been paid to its dangers and relatively small amounts of money spent to control it. Compares the effects and management of hearing impairment due to noise with those resulting from other causes. (Editor)

  9. 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.

  10. Phosphorescent Nanocluster Light-Emitting Diodes.

    PubMed

    Kuttipillai, Padmanaban S; Zhao, Yimu; Traverse, Christopher J; Staples, Richard J; Levine, Benjamin G; Lunt, Richard R

    2016-01-13

    Devices utilizing an entirely new class of earth abundant, inexpensive phosphorescent emitters based on metal-halide nanoclusters are reported. Light-emitting diodes with tunable performance are demonstrated by varying cation substitution to these nanoclusters. Theoretical calculations provide insight about the nature of the phosphorescent emitting states, which involves a strong pseudo-Jahn-Teller distortion.

  11. Phosphorescent Nanocluster Light-Emitting Diodes.

    PubMed

    Kuttipillai, Padmanaban S; Zhao, Yimu; Traverse, Christopher J; Staples, Richard J; Levine, Benjamin G; Lunt, Richard R

    2016-01-13

    Devices utilizing an entirely new class of earth abundant, inexpensive phosphorescent emitters based on metal-halide nanoclusters are reported. Light-emitting diodes with tunable performance are demonstrated by varying cation substitution to these nanoclusters. Theoretical calculations provide insight about the nature of the phosphorescent emitting states, which involves a strong pseudo-Jahn-Teller distortion. PMID:26568044

  12. Green emitting phosphors and blends thereof

    DOEpatents

    Setlur, Anant Achyut; Siclovan, Oltea Puica; Nammalwar, Prasanth Kumar; Sathyanarayan, Ramesh Rao; Porob, Digamber G.; Chandran, Ramachandran Gopi; Heward, William Jordan; Radkov, Emil Vergilov; Briel, Linda Jane Valyou

    2010-12-28

    Phosphor compositions, blends thereof and light emitting devices including white light emitting LED based devices, and backlights, based on such phosphor compositions. The devices include a light source and a phosphor material as described. Also disclosed are phosphor blends including such a phosphor and devices made therefrom.

  13. Long Persistent Light Emitting Diode Indicators

    ERIC Educational Resources Information Center

    Jia, Dongdong; Ma, Yiwei; Hunter, D. N.

    2007-01-01

    An undergraduate laboratory was designed for undergraduate students to make long persistent light emitting diode (LED) indicators using phosphors. Blue LEDs, which emit at 465 nm, were characterized and used as an excitation source. Long persistent phosphors, SrAl[subscript 2]O[subscript 4]:Eu[superscript 2+],Dy[superscript 3+] (green) and…

  14. Active noise reduction

    NASA Astrophysics Data System (ADS)

    Carter, J.

    1984-01-01

    Active Noise Reduction (ANR) techniques, singly and in combination with passive hearing protectors, offer the potential for increased sound protection, enhanced voice communications and improved wearability features for personnel exposed to unacceptable noise conditions. An enhanced closed loop active noise reduction system was miniaturized and incorporated into a standard Air Force flight helmet (HGU-26/P). This report describes the theory of design and operation, prototype configuration and operation, and electroacoustic performance and specifications for the ANR system. This system is theoretically capable of producing in excess of 30 decibels of active noise reduction. Electroacoustic measurements on a flat plate coupler demonstrated approximately 20 decibels of active noise reduction with the prototype unit. A performance evaluation of the integrated ANR unit will be conducted under laboratory and field conditions by government personnel to determine the feasibility of the system for use in military applications.

  15. [Urban noise pollution].

    PubMed

    Chouard, C H

    2001-07-01

    Noise is responsible for cochlear and general damages. Hearing loss and tinnitus greatly depend on sound intensity and duration. Short-duration sound of sufficient intensity (gunshot or explosion) will not be described because they are not currently encountered in our normal urban environment. Sound levels of less than 75 d (A) are unlikely to cause permanent hearing loss, while sound levels of about 85 d (A) with exposures of 8 h per day will produce permanent hearing loss after many years. Popular and largely amplified music is today one of the most dangerous causes of noise induced hearing loss. The intensity of noises (airport, highway) responsible for stress and general consequences (cardiovascular) is generally lower. Individual noise sensibility depends on several factors. Strategies to prevent damage from sound exposure should include the use of individual hearing protection devices, education programs beginning with school-age children, consumer guidance, increased product noise labelling, and hearing conservation programs for occupational settings. PMID:11476007

  16. Noise in coevolving networks

    NASA Astrophysics Data System (ADS)

    Diakonova, Marina; Eguíluz, Víctor M.; San Miguel, Maxi

    2015-09-01

    Coupling dynamics of the states of the nodes of a network to the dynamics of the network topology leads to generic absorbing and fragmentation transitions. The coevolving voter model is a typical system that exhibits such transitions at some critical rewiring. We study the robustness of these transitions under two distinct ways of introducing noise. Noise affecting all the nodes destroys the absorbing-fragmentation transition, giving rise in finite-size systems to two regimes: bimodal magnetization and dynamic fragmentation. Noise targeting a fraction of nodes preserves the transitions but introduces shattered fragmentation with its characteristic fraction of isolated nodes and one or two giant components. Both the lack of absorbing state for homogeneous noise and the shift in the absorbing transition to higher rewiring for targeted noise are supported by analytical approximations.

  17. Regular Wave Propagation Out of Noise in Chemical Active Media

    SciTech Connect

    Alonso, S.; Sendina-Nadal, I.; Perez-Munuzuri, V.; Sancho, J. M.; Sagues, F.

    2001-08-13

    A pacemaker, regularly emitting chemical waves, is created out of noise when an excitable photosensitive Belousov-Zhabotinsky medium, strictly unable to autonomously initiate autowaves, is forced with a spatiotemporal patterned random illumination. These experimental observations are also reproduced numerically by using a set of reaction-diffusion equations for an activator-inhibitor model, and further analytically interpreted in terms of genuine coupling effects arising from parametric fluctuations. Within the same framework we also address situations of noise-sustained propagation in subexcitable media.

  18. Light emitting device having peripheral emissive region

    DOEpatents

    Forrest, Stephen R

    2013-05-28

    Light emitting devices are provided that include one or more OLEDs disposed only on a peripheral region of the substrate. An OLED may be disposed only on a peripheral region of a substantially transparent substrate and configured to emit light into the substrate. Another surface of the substrate may be roughened or include other features to outcouple light from the substrate. The edges of the substrate may be beveled and/or reflective. The area of the OLED(s) may be relatively small compared to the substrate surface area through which light is emitted from the device. One or more OLEDs also or alternatively may be disposed on an edge of the substrate about perpendicular to the surface of the substrate through which light is emitted, such that they emit light into the substrate. A mode expanding region may be included between each such OLED and the substrate.

  19. Light emitting fabric technologies for photodynamic therapy.

    PubMed

    Mordon, Serge; Cochrane, Cédric; Tylcz, Jean Baptiste; Betrouni, Nacim; Mortier, Laurent; Koncar, Vladan

    2015-03-01

    Photodynamic therapy (PDT) is considered to be a promising method for treating various types of cancer. A homogeneous and reproducible illumination during clinical PDT plays a determinant role in preventing under- or over-treatment. The development of flexible light sources would considerably improve the homogeneity of light delivery. The integration of optical fiber into flexible structures could offer an interesting alternative. This paper aims to describe different methods proposed to develop Side Emitting Optical Fibers (SEOF), and how these SEOF can be integrated in a flexible structure to improve light illumination of the skin during PDT. Four main techniques can be described: (i) light blanket integrating side-glowing optical fibers, (ii) light emitting panel composed of SEOF obtained by micro-perforations of the cladding, (iii) embroidery-based light emitting fabric, and (iv) woven-based light emitting fabric. Woven-based light emitting fabrics give the best performances: higher fluence rate, best homogeneity of light delivery, good flexibility.

  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. 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.

  2. Airborne full tensor magnetic gradiometry surveys in the Thuringian basin, Germany

    NASA Astrophysics Data System (ADS)

    Queitsch, M.; Schiffler, M.; Goepel, A.; Stolz, R.; Meyer, M.; Meyer, H.; Kukowski, N.

    2013-12-01

    In this contribution we introduce a newly developed fully operational full tensor magnetic gradiometer (FTMG) instrument based on Superconducting Quantum Interference Devices (SQUIDs) and show example data acquired in 2012 within the framework of the INFLUINS (Integrated Fluid Dynamics in Sedimentary basins) project. This multidisciplinary project aims for a better understanding of movements and interaction between shallow and deep fluids in the Thuringian Basin in the center of Germany. In contrast to mapping total magnetic field intensity (TMI) in conventional airborne magnetic surveys for industrial exploration of mineral deposits and sedimentary basins, our instrument measures all components of the magnetic field gradient tensor using highly sensitive SQUID gradiometers. This significantly constrains the solutions of the inverse problem. Furthermore, information on the ratio between induced and remanent magnetization is obtained. Special care has been taken to reduce motion noise while acquiring data in airborne operation. Therefore, the sensors are mounted in a nonmagnetic and aerodynamically shaped bird made of fiberglas with a high drag tail which stabilizes the bird even at low velocities. The system is towed by a helicopter and kept at 30m above ground during data acquisition. Additionally, the system in the bird incorporates an inertial unit for geo-referencing and enhanced motion noise compensation, a radar altimeter for topographic correction and a GPS system for high precision positioning. Advanced data processing techniques using reference magnetometer and inertial unit data result in a very low system noise of less than 60 pT/m peak to peak in airborne operation. To show the performance of the system we present example results from survey areas within the Thuringian basin and along its bordering highlands. The mapped gradient tensor components show a high correlation to existing geologic maps. Furthermore, the measured gradient components indicate

  3. In vivo imaging of light-emitting probes

    NASA Astrophysics Data System (ADS)

    Rice, Bradley W.; Cable, Michael D.; Nelson, Michael B.

    2001-10-01

    In vivo imaging of cells tagged with light-emitting probes, such as firefly luciferase or fluorescent proteins, is a powerful technology that enables a wide range of biological studies in small research animals. Reporters with emission in the red to infrared (> 600 nm) are preferred due to the low absorption in tissue at these wavelengths. Modeling of photon diffusion through tissue indicates that bioluminescent cell counts as low as a few hundred can be detected subcutaneously, while approximately106 cells are required to detect signals at approximately 2 cm depth in tissue. Signal-to- noise estimates show that cooled back-thinned integrating charge coupled devices (CCDs) are preferred to image-intensified CCDs for this application, mainly due to their high quantum efficiency (approximately 85%) at wavelengths > 600 nm where tissue absorption is low. Instrumentation for in vivo imaging developed at Xenogen is described and several examples of images of mice with bioluminescent cells are presented.

  4. Concentration and distribution of platinum group elements (Pt, Pd, Rh) in airborne particulate matter in Frankfurt am Main, Germany.

    PubMed

    Zereini, Fathi; Alt, Friedrich; Messerschmidt, Jürge; von Bohlen, Alex; Liebl, Karlheinz; Püttmann, Wilhelm

    2004-03-15

    The concentrations and distribution of platinum group elements (Pt, Pd, Rh) in airborne particulate matter were studied in a period of one year from August 2001 to July 2002 in urban and in nonurban areas. Airborne dust samples were collected as a total amount (particles with an aerodynamic diameter <22 microm) and classified using an eight-stage Andersen impactor (<10 microm) at three locations with different traffic density roads in the Frankfurt am Main and nonurban areas. Sampling at the three locations was performed simultaneously for total airborne dust and fractionated airborne dust. Pd was determined by total reflection X-ray fluorescence after Hg coprecipitation. Pt and Rh were analyzed by adsorptive striping voltammetry after HPA digestion. The results show that the PGE concentrations in airborne samples depend on the traffic density. The highest PGE concentrations in air were found in the vicinity of major roads with heavy traffic, and the lowest ones were found in the nonurban area. The presence of PGE at the sampling station relatively free of traffic in a nonurban area hints to a transport of some of the emitted PGE from the city to this station by wind. At all three sampling locations, a heterogeneous distribution of the Pd, Pt, and Rh concentrations during the sampling year can be observed. The sum of PGE concentrations in total airborne dust is comparable with the sum of impactor samples. However, the concentration of Pt and Rh in total airborne dust (<22 microm) is on average higher than in impactor samples (<10 microm). On the contrary, Pd concentration is higher in impactor samples in most cases. The airborne PGE distribution is dominated by Pt, followed by Pd and Rh. The impactor samples are dominated by Pd, followed by Pt and Rh. This fact indicates that palladium occurs mainly in relatively fine airborne particles. The main fraction of PGE is found on average in particle sizes between 1.1 and 4.7 microm. Knowledge of the size distribution of

  5. Application of analysis techniques for low frequency interior noise and vibration of commercial aircraft

    NASA Technical Reports Server (NTRS)

    Landmann, A. E.; Tillema, H. F.; Macgregor, G. R.

    1992-01-01

    Finite element analysis (FEA), statistical energy analysis (SEA), and a power flow method (computer program PAIN) were used to assess low frequency interior noise associated with advanced propeller installations. FEA and SEA models were used to predict cabin noise and vibration and evaluate suppression concepts for structure-borne noise associated with the shaft rotational frequency and harmonics (less than 100 Hz). SEA and PAIN models were used to predict cabin noise and vibration and evaluate suppression concepts for airborne noise associated with engine radiated propeller tones. Both aft-mounted and wing-mounted propeller configurations were evaluated. Ground vibration test data from a 727 airplane modified to accept a propeller engine were used to compare with predictions for the aft-mounted propeller. Similar data from the 767 airplane was used for the wing-mounted comparisons.

  6. Method and apparatus for reducing microwave oscillator output noise

    NASA Technical Reports Server (NTRS)

    Dick, G. John (Inventor); Saunders, Jonathan E. (Inventor)

    1991-01-01

    Microwave oscilltors incorporate r.f. feedback with carrier suppression to reduce phase noise. In a direct feedback oscillator arrngement a circulator is interposed between the r.f. amplifier and the high-Q resonator. The amplifier output is applied to the slightly over-coupled input port of the resonator so that the resultant net return signal is the vectorial difference between the signals emitted and reflected from the resonator. The gain of the r.f. amplifier is chosen to regenerate the forward signal from the net return signal. In a STALO-type arrangement, the resonator is critically coupled and an r.f. amplifier added to the path of the net return signal. The sensitivity of the STALO-type feedback loop is thereby enhanced while added amplifier noise is minimized by the superposition of the signals emitted by and reflected from the resonator.

  7. Improved Airborne Gravity Results Using New Relative Gravity Sensor Technology

    NASA Astrophysics Data System (ADS)

    Brady, N.

    2013-12-01

    Airborne gravity data has contributed greatly to our knowledge of subsurface geophysics particularly in rugged and otherwise inaccessible areas such as Antarctica. Reliable high quality GPS data has renewed interest in improving the accuracy of airborne gravity systems and recent improvements in the electronic control of the sensor have increased the accuracy and ability of the classic Lacoste and Romberg zero length spring gravity meters to operate in turbulent air conditions. Lacoste and Romberg type gravity meters provide increased sensitivity over other relative gravity meters by utilizing a mass attached to a horizontal beam which is balanced by a ';zero length spring'. This type of dynamic gravity sensor is capable of measuring gravity changes on the order of 0.05 milliGals in laboratory conditions but more commonly 0.7 to 1 milliGal in survey use. The sensor may have errors induced by the electronics used to read the beam position as well as noise induced by unwanted accelerations, commonly turbulence, which moves the beam away from its ideal balance position otherwise known as the reading line. The sensor relies on a measuring screw controlled by a computer which attempts to bring the beam back to the reading line position. The beam is also heavily damped so that it does not react to most unwanted high frequency accelerations. However this heavily damped system is slow to react, particularly in turns where there are very high Eotvos effects. New sensor technology utilizes magnetic damping of the beam coupled with an active feedback system which acts to effectively keep the beam locked at the reading line position. The feedback system operates over the entire range of the system so there is now no requirement for a measuring screw. The feedback system operates at very high speed so that even large turbulent events have minimal impact on data quality and very little, if any, survey line data is lost because of large beam displacement errors. Airborne testing

  8. Design of an Airborne Portable Remote Imaging Spectrometer (PRISM) for the Coastal Ocean

    NASA Technical Reports Server (NTRS)

    Mouroulis, P.; vanGorp, B.; Green, R. O.; Cohen, D.; Wilson, D.; Randall, D.; Rodriguez, J.; Polanco, O.; Dierssen, H.; Balasubramanian, K.; Vargas, R.; Hein, R.; Sobel, H.; Eastwood, M.

    2010-01-01

    PRISM is a pushbroom imaging spectrometer currently under development at the Jet Propulsion Laboratory, intended to address the needs of airborne coastal ocean science research. We describe here the instrument design and the technologies that enable it to achieve its distinguishing characteristics. PRISM covers the 350-1050 nm range with a 3.1 nm sampling and a 33(deg) field of view. The design provides for high signal to noise ratio, high uniformity of response, and low polarization sensitivity. The complete instrument also incorporates two additional wavelength bands at 1240 and 1610 nm in a spot radiometer configuration to aid with atmospheric correction.

  9. Effects of background noise on total noise annoyance

    NASA Technical Reports Server (NTRS)

    Willshire, K. F.

    1987-01-01

    Two experiments were conducted to assess the effects of combined community noise sources on annoyance. The first experiment baseline relationships between annoyance and noise level for three community noise sources (jet aircraft flyovers, traffic and air conditioners) presented individually. Forty eight subjects evaluated the annoyance of each noise source presented at four different noise levels. Results indicated the slope of the linear relationship between annoyance and noise level for the traffic noise was significantly different from that of aircraft and of air conditioner noise, which had equal slopes. The second experiment investigated annoyance response to combined noise sources, with aircraft noise defined as the major noise source and traffic and air conditioner noise as background noise sources. Effects on annoyance of noise level differences between aircraft and background noise for three total noise levels and for both background noise sources were determined. A total of 216 subjects were required to make either total or source specific annoyance judgements, or a combination of the two, for a wide range of combined noise conditions.

  10. Using special functions to model the propagation of airborne diseases

    NASA Astrophysics Data System (ADS)

    Bolaños, Daniela

    2014-06-01

    Some special functions of the mathematical physics are using to obtain a mathematical model of the propagation of airborne diseases. In particular we study the propagation of tuberculosis in closed rooms and we model the propagation using the error function and the Bessel function. In the model, infected individual emit pathogens to the environment and this infect others individuals who absorb it. The evolution in time of the concentration of pathogens in the environment is computed in terms of error functions. The evolution in time of the number of susceptible individuals is expressed by a differential equation that contains the error function and it is solved numerically for different parametric simulations. The evolution in time of the number of infected individuals is plotted for each numerical simulation. On the other hand, the spatial distribution of the pathogen around the source of infection is represented by the Bessel function K0. The spatial and temporal distribution of the number of infected individuals is computed and plotted for some numerical simulations. All computations were made using software Computer algebra, specifically Maple. It is expected that the analytical results that we obtained allow the design of treatment rooms and ventilation systems that reduce the risk of spread of tuberculosis.

  11. Mutagenicity of airborne particulates in the rubber industry.

    PubMed

    Barański, B; Indulski, J; Janik-Spiechowicz, E; Palus, J

    1989-12-01

    The aim of this work was to evaluate the mutagenic activity of airborne particulate matter in the rubber industry. Air was sucked through Whatman glass-fibre filters with Staplex pumps and adsorbed substances and fume particles were extracted with acetone or toluene for 2 h in a ultrasonic cleaner. After separation of the insoluble solid phase by filtration, solvent was evaporated at a temperature of 70 degrees C in an argon atmosphere. The residue was stored at -20 degrees C. Mutagenicity was determined by the Salmonella plate incorporation assay with the tester strain TA98 and activity is related either to the weight of aerosol (rev mg-1) or to the volume of atmospheric sample (rev m-3). The fumes emitted from the tyre tread line, calender feeding, and tyre vulcanizing processes, showed the highest mutagenic activity (55-211 rev mg-1, + S9). At these and at other workplaces (extruder mill, carbon black station, mixer loading), mutagenic activity related to the volume of air was in the range of 22-158 rev m-3, + S9. The results indicate the need to reduce and monitor mutagenic contamination in order to increase the safety of work in the rubber industry. PMID:2693511

  12. Airborne Microalgae: Insights, Opportunities, and Challenges.

    PubMed

    Tesson, Sylvie V M; Skjøth, Carsten Ambelas; Šantl-Temkiv, Tina; Löndahl, Jakob

    2016-04-01

    Airborne dispersal of microalgae has largely been a blind spot in environmental biological studies because of their low concentration in the atmosphere and the technical limitations in investigating microalgae from air samples. Recent studies show that airborne microalgae can survive air transportation and interact with the environment, possibly influencing their deposition rates. This minireview presents a summary of these studies and traces the possible route, step by step, from established ecosystems to new habitats through air transportation over a variety of geographic scales. Emission, transportation, deposition, and adaptation to atmospheric stress are discussed, as well as the consequences of their dispersal on health and the environment and state-of-the-art techniques to detect and model airborne microalga dispersal. More-detailed studies on the microalga atmospheric cycle, including, for instance, ice nucleation activity and transport simulations, are crucial for improving our understanding of microalga ecology, identifying microalga interactions with the environment, and preventing unwanted contamination events or invasions. PMID:26801574

  13. 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.

  14. Airborne pollen trends in the Iberian Peninsula.

    PubMed

    Galán, C; Alcázar, P; Oteros, J; García-Mozo, H; Aira, M J; Belmonte, J; Diaz de la Guardia, C; Fernández-González, D; Gutierrez-Bustillo, M; Moreno-Grau, S; Pérez-Badía, R; Rodríguez-Rajo, J; Ruiz-Valenzuela, L; Tormo, R; Trigo, M M; Domínguez-Vilches, E

    2016-04-15

    Airborne pollen monitoring is an effective tool for studying the reproductive phenology of anemophilous plants, an important bioindicator of plant behavior. Recent decades have revealed a trend towards rising airborne pollen concentrations in Europe, attributing these trends to an increase in anthropogenic CO2 emissions and temperature. However, the lack of water availability in southern Europe may prompt a trend towards lower flowering intensity, especially in herbaceous plants. Here we show variations in flowering intensity by analyzing the Annual Pollen Index (API) of 12 anemophilous taxa across 12 locations in the Iberian Peninsula, over the last two decades, and detecting the influence of the North Atlantic Oscillation (NAO). Results revealed differences in the distribution and flowering intensity of anemophilous species. A negative correlation was observed between airborne pollen concentrations and winter averages of the NAO index. This study confirms that changes in rainfall in the Mediterranean region, attributed to climate change, have an important impact on the phenology of plants.

  15. Airborne Microalgae: Insights, Opportunities, and Challenges

    PubMed Central

    Skjøth, Carsten Ambelas; Šantl-Temkiv, Tina; Löndahl, Jakob

    2016-01-01

    Airborne dispersal of microalgae has largely been a blind spot in environmental biological studies because of their low concentration in the atmosphere and the technical limitations in investigating microalgae from air samples. Recent studies show that airborne microalgae can survive air transportation and interact with the environment, possibly influencing their deposition rates. This minireview presents a summary of these studies and traces the possible route, step by step, from established ecosystems to new habitats through air transportation over a variety of geographic scales. Emission, transportation, deposition, and adaptation to atmospheric stress are discussed, as well as the consequences of their dispersal on health and the environment and state-of-the-art techniques to detect and model airborne microalga dispersal. More-detailed studies on the microalga atmospheric cycle, including, for instance, ice nucleation activity and transport simulations, are crucial for improving our understanding of microalga ecology, identifying microalga interactions with the environment, and preventing unwanted contamination events or invasions. PMID:26801574

  16. Nature of orchestral noise.

    PubMed

    O'Brien, Ian; Wilson, Wayne; Bradley, Andrew

    2008-08-01

    Professional orchestral musicians are at risk of exposure to excessive noise when at work. This is an industry-wide problem that threatens not only the hearing of orchestral musicians but also the way orchestras operate. The research described in this paper recorded noise levels within a professional orchestra over three years in order to provide greater insight to the orchestral noise environment; to guide future research into orchestral noise management and hearing conservation strategies; and to provide a basis for the future education of musicians and their managers. Every rehearsal, performance, and recording from May 2004 to May 2007 was monitored, with the woodwind, brass, and percussion sections monitored in greatest detail. The study recorded dBALEQ and dBC peak data, which are presented in graphical form with accompanying summarized data tables. The findings indicate that the principal trumpet, first and third horns, and principal trombone are at greatest risk of exposure to excessive sustained noise levels and that the percussion and timpani are at greatest risk of exposure to excessive peak noise levels. However, the findings also strongly support the notion that the true nature of orchestral noise is a great deal more complex than this simple statement would imply.

  17. [The fetus and noise].

    PubMed

    Brezinka, C; Lechner, T; Stephan, K

    1997-01-01

    From 23 weeks of gestation some and from 28 weeks all healthy fetuses are capable of reacting to sound stimulation. The intrauterine acoustic environment is dominated by maternal sounds--heartbeat, breathing, the mother's voice, borborygmi and sounds caused by body movements. Background noise is never below 28 dB and can rise to 84 dB when the mother is singing. Noises that are meant to reach the fetus must be louder than the background noise and must be of low frequency as high frequency sounds are damped by maternal tissue. Vibroacoustic stimulation tests (VAST) have become popular in pregnancy surveillance over the last 20 years, mostly using an artificial larynx. Advantages and problems of the various VAST protocols in fetal monitoring are discussed in the light of animal experiments and clinical studies. Health legislation laws in most countries forbid pregnant women to work in surroundings with a high noise level (80 dB continuous noise and/or rapid impulse noise changes of 40 dB). Whereas regulations for pregnant women are easy to enforce in industry, pregnant women employed in discos or performing as musicians spend most of their working day exposed to noise impact higher than the recommended limit.

  18. Analyzing nocturnal noise stratification.

    PubMed

    Rey Gozalo, Guillermo; Barrigón Morillas, Juan Miguel; Gómez Escobar, Valentín

    2014-05-01

    Pollution associated to traffic can be considered as one of the most relevant pollution sources in our cities; noise is one of the major components of traffic pollution; thus, efforts are necessary to search adequate noise assessment methods and low pollution city designs. Different methods have been proposed for the evaluation of noise in cities, including the categorization method, which is based on the functionality concept. Until now, this method has only been studied (with encouraging results) for short-term, diurnal measurements, but nocturnal noise presents a behavior clearly different on respect to the diurnal one. In this work 45 continuous measurements of approximately one week each in duration are statistically analyzed to identify differences between the proposed categories. The results show that the five proposed categories highlight the noise stratification of the studied city in each period of the day (day, evening, and night). A comparison of the continuous measurements with previous short-term measurements indicates that the latter can be a good approximation of the former in diurnal period, reducing the resource expenditure for noise evaluation. Annoyance estimated from the measured noise levels was compared with the response of population obtained from a questionnaire with good agreement. The categorization method can yield good information about the distribution of a pollutant associated to traffic in our cities in each period of the day and, therefore, is a powerful tool for town planning and the design of pollution prevention policies.

  19. Noise-Induced Hearing Loss

    MedlinePlus

    ... Info » Hearing, Ear Infections, and Deafness Noise-Induced Hearing Loss On this page: What is noise-induced hearing ... additional information about NIHL? What is noise-induced hearing loss? Every day, we experience sound in our environment, ...

  20. Flight effects of fan noise

    NASA Astrophysics Data System (ADS)

    Chestnutt, D.

    1982-09-01

    Simulation of inflight fan noise and flight effects was discussed. The status of the overall program on the flight effects of fan noise was reviewed, and flight to static noise comparisons with the JT15D engine were displayed.

  1. Flight effects of fan noise

    NASA Technical Reports Server (NTRS)

    Chestnutt, D. (Editor)

    1982-01-01

    Simulation of inflight fan noise and flight effects was discussed. The status of the overall program on the flight effects of fan noise was reviewed, and flight to static noise comparisons with the JT15D engine were displayed.

  2. Low frequency noise distributed-feedback ytterbium fibre laser

    SciTech Connect

    Nikulin, M A; Babin, S A; Kablukov, S I; Dmitriev, Aleksandr K; Dychkov, Aleksandr S; Lugovoy, Aleksei A; Pecherskii, Yu Ya

    2009-10-31

    We report a single-frequency 1-W fibre laser source emitting at 1093 nm, composed of a distributed-feedback ytterbium fibre laser and fibre-optic amplifier. The laser frequency was stabilised by side-locking to a transmission peak of a Fabry - Perot interferometer, and the residual frequency noise spectrum of the laser was measured. Our results indicate that the laser linewidth can be narrowed down below 1 kHz. (lasers)

  3. 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

  4. 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

  5. Correlations among atmospheric elements, airborne particulate matter, benzene extracts, benzo(a)pyrene, NO, NO 2 and so 2 concentrations in Japan

    NASA Astrophysics Data System (ADS)

    Fukino, H.; Mimura, S.; Inoue, K.; Yamane, Y.

    Concentration levels of elements, airborne particulate matter, benzene extracts, benzo(a)pyrene B(a)P, NO, NO 2 and SO 2 in five residential areas were seasonally determined from May 1979 to January 1980. These air pollutants exhibited higher concentration in autumn and winter than in spring and summer. These were correlations among Pb, Cu, Ni, V and Se, among Si, Fe, Al and Ti and among NO, NO 2, B(a)P, benzene extracts and airborne particulate matter. NO, NO 2, B(a)P, benzene extracts and airborne particulate matter were correlated with Pb, Cu, Ni, V and Se, but not appreciably with Si, Fe, Al and Ti. On the basis of correlations between various air pollutants, the emitting source of the air pollutants and the health hazard by combined air pollution were discussed.

  6. Simulated high speed flight effects on supersonic jet noise

    NASA Technical Reports Server (NTRS)

    Norum, Thomas D.; Brown, Martha C.

    1993-01-01

    A free jet is utilized to investigate the changes in the noise received from supersonic jets in high speed subsonic flight. Flight Mach numbers to 0.9 are simulated for supersonic jets with fully expanded Mach numbers between 1 and 2. Plume pressure measurements show only minor changes in the shock structure of off-design jets up to a Mach number of 0.6. Correspondingly, far-field noise measurements indicate little change to the broadband shock noise emitted at right angles to the jet. However, measurements within the free jet show that convection effects on the noise are substantial, and that the point source convective amplification that is proportional to the fourth power of the Doppler factor may apply for broadband shock noise in flight. Measurements of jet mixing noise for an on-design supersonic jet show that the current predictions of mixing noise in flight can be extended to flight Mach numbers of at least 0.5.

  7. Jet engine noise and infrared plume correlation field campaign

    NASA Astrophysics Data System (ADS)

    Cunio, Phillip M.; Weber, Reed A.; Knobel, Kimberly R.; Smith, Christine; Draudt, Andy

    2015-09-01

    Jet engine noise can be a health hazard and environmental pollutant, particularly affecting personnel working in close proximity to jet engines, such as airline mechanics. Mitigating noise could reduce the potential for hearing loss in runway workers; however, there exists a very complex relationship between jet engine design parameters, operating conditions, and resultant noise power levels, and understanding and characterizing this relationship is a key step in mitigating jet engine noise effects. We demonstrate initial results highlighting the utility of high-speed imaging (hypertemporal imaging) in correlating the infrared signatures of jet engines with acoustic noise. This paper builds on prior theoretical analysis of jet engine infrared signatures and their potential relationships to jet engine acoustic emissions. This previous work identified the region of the jet plume most likely to emit both in infrared and in acoustic domains, and it prompted the investigation of wave packets as a physical construct tying together acoustic and infrared energy emissions. As a means of verifying these assertions, a field campaign to collect relevant data was proposed, and data collection was carried out with a bank of infrared instruments imaging a T700 turboshaft engine undergoing routine operational testing. The detection of hypertemporal signatures in association with acoustic signatures of jet engines enables the use of a new domain in characterizing jet engine noise. This may in turn enable new methods of predicting or mitigating jet engine noise, which could lead to socioeconomic benefits for airlines and other operators of large numbers of jet engines.

  8. Noise considerations for tiltrotor

    NASA Technical Reports Server (NTRS)

    Huston, Robert J.; Golub, Robert A.; Yu, James C.

    1989-01-01

    A projection is made of the technology-development requirements faced by aircraft designers contemplating the evolution of V-22-type tilt-rotor aircraft technology into a civilian tilt-rotor commuter aircraft of the requisite scale and payload. These research challenges are noted to often involve the reduction of noise level to values tolerated by passengers within the cabin and communities in the vicinity of airports, especially during hover and in the course of transition from vertical to horizontal flight (and vice-versa). Noise-generation and noise-radiation characteristics research has been undertaken using the XV-15 tilt-rotor proof-of-concept aircraft.

  9. Propfan noise propagation

    NASA Technical Reports Server (NTRS)

    George, Albert R.; Sim, Ben WEL-C.

    1993-01-01

    The unconventional supersonic tip speed of advanced propellers has led to uncertainties about Propfan's noise acceptability and compliance with Federal Aviation Noise Regulation (FAR 36). Overhead flight testing of the Propfan with an SR-7L blade during 1989's Propfan Test Assessment (PTA) Program have shown unexpectedly high far-field sound pressure levels. This study here attempts to provide insights into the acoustics of a single-rotating propeller (SRP) with supersonic tip speed. At the same time, the role of the atmosphere in shaping the far-field noise characteristics is investigated.

  10. Control of jet noise

    NASA Astrophysics Data System (ADS)

    Schreck, Stefan

    To investigate the possibility of active control of jet noise, knowledge of the noise generation mechanisms in natural jets is essential. Once these mechanisms are determined, active control can be used to manipulate the noise production processes. We investigated the evolution of the flow fields and the acoustic fields of rectangular and circular jets. A predominant flapping mode was found in the supersonic rectangular jets. We hope to increase the spreading of supersonic jets by active control of the flapping mode found in rectangular supersonic jets.

  11. Quantum phase slip noise

    NASA Astrophysics Data System (ADS)

    Semenov, Andrew G.; Zaikin, Andrei D.

    2016-07-01

    Quantum phase slips (QPSs) generate voltage fluctuations in superconducting nanowires. Employing the Keldysh technique and making use of the phase-charge duality arguments, we develop a theory of QPS-induced voltage noise in such nanowires. We demonstrate that quantum tunneling of the magnetic flux quanta across the wire yields quantum shot noise which obeys Poisson statistics and is characterized by a power-law dependence of its spectrum SΩ on the external bias. In long wires, SΩ decreases with increasing frequency Ω and vanishes beyond a threshold value of Ω at T →0 . The quantum coherent nature of QPS noise yields nonmonotonous dependence of SΩ on T at small Ω .

  12. Predictors of airborne endotoxin concentrations in inner city homes.

    PubMed

    Mazique, D; Diette, G B; Breysse, P N; Matsui, E C; McCormack, M C; Curtin-Brosnan, J; Williams, D L; Peng, R D; Hansel, N N

    2011-05-01

    Few studies have assessed in home factors which contribute to airborne endotoxin concentrations. In 85 inner city Baltimore homes, we found no significant correlation between settled dust and airborne endotoxin concentrations. Certain household activities and characteristics, including frequency of dusting, air conditioner use and type of flooring, explained 36-42% of the variability of airborne concentrations. Measurements of both airborne and settled dust endotoxin concentrations may be needed to fully characterize domestic exposure in epidemiologic investigations. PMID:21429483

  13. Fourth Aircraft Interior Noise Workshop

    NASA Technical Reports Server (NTRS)

    Stephens, David G. (Compiler)

    1992-01-01

    The fourth in a series of NASA/SAE Interior Noise Workshops was held on May 19 and 20, 1992. The theme of the workshop was new technology and applications for aircraft noise with emphasis on source noise prediction; cabin noise prediction; cabin noise control, including active and passive methods; and cabin interior noise procedures. This report is a compilation of the presentations made at the meeting which addressed the above issues.

  14. Sandia Multispectral Airborne Lidar for UAV Deployment

    SciTech Connect

    Daniels, J.W.; Hargis,Jr. P.J.; Henson, T.D.; Jordan, J.D.; Lang, A.R.; Schmitt, R.L.

    1998-10-23

    Sandia National Laboratories has initiated the development of an airborne system for W laser remote sensing measurements. System applications include the detection of effluents associated with the proliferation of weapons of mass destruction and the detection of biological weapon aerosols. This paper discusses the status of the conceptual design development and plans for both the airborne payload (pointing and tracking, laser transmitter, and telescope receiver) and the Altus unmanned aerospace vehicle platform. Hardware design constraints necessary to maintain system weight, power, and volume limitations of the flight platform are identified.

  15. Assessing inhalation exposure from airborne soil contaminants

    SciTech Connect

    Shinn, J.H.

    1998-04-01

    A method of estimation of inhalation exposure to airborne soil contaminants is presented. this method is derived from studies of airborne soil particles with radioactive tags. The concentration of contaminants in air (g/m{sup 3}) can be derived from the product of M, the suspended respirable dust mass concentration (g/m{sup 3}), S, the concentration of contaminant in the soil (g/g), and E{sub f}, an enhancement factor. Typical measurement methods and values of M, and E{sub f} are given along with highlights of experiences with this method.

  16. 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.

  17. National center for airborne laser mapping proposed

    NASA Astrophysics Data System (ADS)

    Carter, Bill; Shrestha, Ramesh L.; Dietrich, Bill

    Researchers from universities, U.S. government agencies, U.S. national laboratories, and private industry met in the spring to learn about the current capabilities of Airborne Laser Swath Mapping (ALSM), share their experiences in using the technology for a wide variety of research applications, outline research that would be made possible by research-grade ALSM data, and discuss the proposed operation and management of the brand new National Center for Airborne Laser Mapping (NCALM).The workshop successfully identified a community of researchers with common interests in the advancement and use of ALSM—a community which strongly supports the immediate establishment of the NCALM.

  18. Laboratory testing of airborne brake wear particle emissions using a dynamometer system under urban city driving cycles

    NASA Astrophysics Data System (ADS)

    Hagino, Hiroyuki; Oyama, Motoaki; Sasaki, Sousuke

    2016-04-01

    To measure driving-distance-based mass emission factors for airborne brake wear particulate matter (PM; i.e., brake wear particles) related to the non-asbestos organic friction of brake assembly materials (pads and lining), and to characterize the components of brake wear particles, a brake wear dynamometer with a constant-volume sampling system was developed. Only a limited number of studies have investigated brake emissions under urban city driving cycles that correspond to the tailpipe emission test (i.e., JC08 or JE05 mode of Japanese tailpipe emission test cycles). The tests were performed using two passenger cars and one middle-class truck. The observed airborne brake wear particle emissions ranged from 0.04 to 1.4 mg/km/vehicle for PM10 (particles up to 10 μm (in size), and from 0.04 to 1.2 mg/km/vehicle for PM2.5. The proportion of brake wear debris emitted as airborne brake wear particles was 2-21% of the mass of wear. Oxygenated carbonaceous components were included in the airborne PM but not in the original friction material, which indicates that changes in carbon composition occurred during the abrasion process. Furthermore, this study identified the key tracers of brake wear particles (e.g., Fe, Cu, Ba, and Sb) at emission levels comparable to traffic-related atmospheric environments.

  19. Association of the mutagenicity of airborne particles with the direct emission from combustion processes investigated in Osaka, Japan

    NASA Astrophysics Data System (ADS)

    Kameda, Takayuki; Sanukida, Satoshi; Inazu, Koji; Hisamatsu, Yoshiharu; Maeda, Yasuaki; Takenaka, Norimichi; Bandow, Hiroshi

    The association of the direct-acting mutagenicity of soluble organic fraction of airborne particles toward Salmonella typhimurium YG1024 strain with the direct emission was investigated at a roadside and at a residential area in Osaka, Japan. The direct-acting mutagenicity was evaluated as mutagenic activity per unit volume of ambient air (rev m -3) and/or that per airborne particulate weight collected on a filter (rev mg -1). The annual or diurnal changes of the mutagenicity of airborne particles at the residential site showed similar patterns to those of some gaseous pollutants such as NO 2 and SO 2, which were emitted from combustion processes. This result indicates that the mutagenicity is mainly attributable to the primary emissions. From the analysis of the relationship between the wind sector and the mutagenic intensity, rev m -3 and rev mg -1 values were strongly affected by the emissions from the fixed sources and from the mobile sources, respectively. The rev m -3 value and concentration of 1-nitropyrene (1-NP) in unit per m 3 at the roadside were a factor of 2.6 and 2.8 higher than those at the residential site, respectively, but the rev mg -1 value and concentration of 1-NP in unit per mg at the roadside were substantially comparable to those at the residential area. These observations suggest that the characteristics of the airborne particles can be attributed to the automotive emissions even at the suburban area.

  20. Noise Transmission Characteristics of Damped Plexiglas Windows

    NASA Technical Reports Server (NTRS)

    Gibbs, Gary P.; Buehrle, Ralph D.; Klos, Jacob; Brown, Sherilyn A.

    2002-01-01

    Most general aviation aircraft utilize single layer plexiglas material for the windshield and side windows. Adding noise control treatments to transparent panels is a challenging problem. In this paper, damped plexiglas windows are evaluated for replacement of conventional windows in general aviation aircraft to reduce the structure-borne and airborne noise transmitted into the interior. In contrast to conventional solid windows, the damped plexiglas window panels are fabricated using two or three layers of plexiglas with transparent viscoelastic damping material sandwiched between the layers. Results from acoustic tests conducted in the NASA Langley Structural Acoustic Loads and Transmission (SALT) facility are used to compare different designs of the damped plexiglas panels with solid windows of the same nominal thickness. Comparisons of the solid and damped plexiglas panels show reductions in the radiated sound power of up to 8 dB at low frequency resonances and as large as 4.5 dB over a 4000 Hz bandwidth. The weight of the viscoelastic treatment was approximately 1% of the panel mass. Preliminary FEM/BEM modeling shows good agreement with experimental results for radiated sound power.

  1. Cochlear implant optimized noise reduction.

    PubMed

    Mauger, Stefan J; Arora, Komal; Dawson, Pam W

    2012-12-01

    Noise-reduction methods have provided significant improvements in speech perception for cochlear implant recipients, where only quality improvements have been found in hearing aid recipients. Recent psychoacoustic studies have suggested changes to noise-reduction techniques specifically for cochlear implants, due to differences between hearing aid recipient and cochlear implant recipient hearing. An optimized noise-reduction method was developed with significantly increased temporal smoothing of the signal-to-noise ratio estimate and a more aggressive gain function compared to current noise-reduction methods. This optimized noise-reduction algorithm was tested with 12 cochlear implant recipients over four test sessions. Speech perception was assessed through speech in noise tests with three noise types; speech-weighted noise, 20-talker babble and 4-talker babble. A significant speech perception improvement using optimized noise reduction over standard processing was found in babble noise and speech-weighted noise and over a current noise-reduction method in speech-weighted noise. Speech perception in quiet was not degraded. Listening quality testing for noise annoyance and overall preference found significant improvements over the standard processing and over a current noise-reduction method in speech-weighted and babble noise types. This optimized method has shown significant speech perception and quality improvements compared to the standard processing and a current noise-reduction method.

  2. 14 CFR 125.223 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Airborne weather radar equipment... Equipment Requirements § 125.223 Airborne weather radar equipment requirements. (a) No person may operate an airplane governed by this part in passenger-carrying operations unless approved airborne weather...

  3. 14 CFR 121.357 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Airborne weather radar equipment... § 121.357 Airborne weather radar equipment requirements. (a) No person may operate any transport... December 31, 1964, unless approved airborne weather radar equipment has been installed in the airplane....

  4. 14 CFR 125.223 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Airborne weather radar equipment... Equipment Requirements § 125.223 Airborne weather radar equipment requirements. (a) No person may operate an airplane governed by this part in passenger-carrying operations unless approved airborne weather...

  5. 14 CFR 125.223 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Airborne weather radar equipment... Equipment Requirements § 125.223 Airborne weather radar equipment requirements. (a) No person may operate an airplane governed by this part in passenger-carrying operations unless approved airborne weather...

  6. 14 CFR 135.175 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Airborne weather radar equipment... Aircraft and Equipment § 135.175 Airborne weather radar equipment requirements. (a) No person may operate a large, transport category aircraft in passenger-carrying operations unless approved airborne...

  7. 14 CFR 135.175 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Airborne weather radar equipment... Aircraft and Equipment § 135.175 Airborne weather radar equipment requirements. (a) No person may operate a large, transport category aircraft in passenger-carrying operations unless approved airborne...

  8. 14 CFR 121.357 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Airborne weather radar equipment... § 121.357 Airborne weather radar equipment requirements. (a) No person may operate any transport... December 31, 1964, unless approved airborne weather radar equipment has been installed in the airplane....

  9. 14 CFR 125.223 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Airborne weather radar equipment... Equipment Requirements § 125.223 Airborne weather radar equipment requirements. (a) No person may operate an airplane governed by this part in passenger-carrying operations unless approved airborne weather...

  10. 14 CFR 121.357 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Airborne weather radar equipment... § 121.357 Airborne weather radar equipment requirements. (a) No person may operate any transport... December 31, 1964, unless approved airborne weather radar equipment has been installed in the airplane....

  11. 14 CFR 135.175 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Airborne weather radar equipment... Aircraft and Equipment § 135.175 Airborne weather radar equipment requirements. (a) No person may operate a large, transport category aircraft in passenger-carrying operations unless approved airborne...

  12. 14 CFR 125.223 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Airborne weather radar equipment... Equipment Requirements § 125.223 Airborne weather radar equipment requirements. (a) No person may operate an airplane governed by this part in passenger-carrying operations unless approved airborne weather...

  13. 14 CFR 121.357 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Airborne weather radar equipment... § 121.357 Airborne weather radar equipment requirements. (a) No person may operate any transport... December 31, 1964, unless approved airborne weather radar equipment has been installed in the airplane....

  14. 14 CFR 135.175 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Airborne weather radar equipment... Aircraft and Equipment § 135.175 Airborne weather radar equipment requirements. (a) No person may operate a large, transport category aircraft in passenger-carrying operations unless approved airborne...

  15. 14 CFR 135.175 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Airborne weather radar equipment... Aircraft and Equipment § 135.175 Airborne weather radar equipment requirements. (a) No person may operate a large, transport category aircraft in passenger-carrying operations unless approved airborne...

  16. 14 CFR 121.357 - Airborne weather radar equipment requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Airborne weather radar equipment... § 121.357 Airborne weather radar equipment requirements. (a) No person may operate any transport... December 31, 1964, unless approved airborne weather radar equipment has been installed in the airplane....

  17. Organic light emitting devices for illumination

    DOEpatents

    Hack, Michael; Lu, Min-Hao Michael; Weaver, Michael S.

    2010-02-16

    An organic light emitting device is provided. The device has a plurality of regions, each region having an organic emissive layer adapted to emit a different spectrum of light. The regions in combination emit light suitable for illumination purposes. The area of each region may be selected such that the device is more efficient that an otherwise equivalent device having regions of equal size. The regions may have an aspect ratio of at least about four. All parts of any given region may be driven at the same current.

  18. Organic light emitting devices for illumination

    DOEpatents

    Hack, Michael; Lu, Min-Hao Michael; Weaver, Michael S.

    2012-01-24

    An organic light emitting device an a method of obtaining illumination from such a device is provided. The device has a plurality of regions, each region having an organic emissive layer adapted to emit a different spectrum of light. The regions in combination emit light suitable for illumination purposes. The area of each region may be selected such that the device is more efficient than an otherwise equivalent device having regions of equal size. The regions may have an aspect ratio of at least about four. All parts of any given region may be driven at the same current.

  19. Wheat Under LED's (Light Emitting Diodes)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Astroculture is a suite of technologies used to produce and maintain a closed controlled environment for plant growth. The two most recent missions supported growth of potato, dwarf wheat, and mustard plants, and provided scientists with the first opportunity to conduct true plant research in space. Light emitting diodes have particular usefulness for plant growth lighting because they emit a much smaller amount of radiant heat than do conventional lighting sources and because they have potential of directing a higher percentage of the emitted light onto plants surfaces. Furthermore, the high output LED's have emissions in the 600-700 nm waveband, which is of highest efficiency for photosynthesis by plants.

  20. Shot noise startup of the 6 NM SASE FEL at the Tesla Test Facility

    SciTech Connect

    Pierini, P.; Fawley, W.M.

    1995-12-31

    We present here an analysis of the shot noise startup of the 6 nm SASE FEI proposal at the TESLA Test Facility in DESY The statistical of the saturation length and output power due to the intrinsic randomness of the noise startup are investigated with the use of the 2D time dependent code GINGER, that takes into account propagation effects and models shot noise. We then provide estimates for the spectral contents and linewidth of the emitted radiation and describe its spiking characteristics. The output radiation will develop superradiant spikes seeded by the shot noise in the electron beam, which can entrance the average emitted power at the expense of some spectral broadening.

  1. HVAC equipment and noise

    SciTech Connect

    Cerami, V.J.

    1996-03-01

    The purpose of this article is to define how the selection of HVAC equipment and layout impact the achievable noise criteria (NC) levels in occupied spaces. It will focus on the design of HVAC systems that employ floor-by-floor air handling/air conditioning units and their acoustical ramifications. This is of increasing importance since tenants require incorporation of noise limits in lease agreements.

  2. JPL noise control program

    NASA Technical Reports Server (NTRS)

    Klascius, A. F.

    1975-01-01

    Exposures of personnel to noise pollution at the Jet Propulsion Laboratories, Pasadena, California, were investigated. As a result of the study several protective measures were taken: (1) employees exposed to noise hazards were required to wear ear-protection devices, (2) mufflers and air diversion devices were installed around the wind tunnels; and (3) all personnel that are required to wear ear protection are given annual audimeter tests.

  3. Television noise reduction device

    NASA Technical Reports Server (NTRS)

    Gordon, B. L.; Stamps, J. C. (Inventor)

    1975-01-01

    A noise reduction system that divides the color video signal into its luminance and chrominance components is reported. The luminance component of a given frame is summed with the luminance component of at least one preceding frame which was stored on a disc recorder. The summation is carried out so as to achieve a signal amplitude equivalent to that of the original signal. The averaged luminance signal is then recombined with the chrominance signal to achieve a noise-reduced television signal.

  4. Noise Abatement Materials

    NASA Technical Reports Server (NTRS)

    1986-01-01

    A former NASA employee who discovered a kind of plastic that soaked up energy, dampened vibrations, and was a good noise abatement material, founded a company to market noise deadening adhesives, sheets, panels and enclosures. Known as SMART products, they are 75-80% lighter than ordinary soundproofing material and have demonstrated a high degree of effectiveness. The company, Varian Associates, makes enclosures for high voltage terminals and other electronic system components, and easily transportable audiometric test booths.

  5. Low-pass parabolic FFT filter for airborne and satellite lidar signal processing.

    PubMed

    Jiao, Zhongke; Liu, Bo; Liu, Enhai; Yue, Yongjian

    2015-01-01

    In order to reduce random errors of the lidar signal inversion, a low-pass parabolic fast Fourier transform filter (PFFTF) was introduced for noise elimination. A compact airborne Raman lidar system was studied, which applied PFFTF to process lidar signals. Mathematics and simulations of PFFTF along with low pass filters, sliding mean filter (SMF), median filter (MF), empirical mode decomposition (EMD) and wavelet transform (WT) were studied, and the practical engineering value of PFFTF for lidar signal processing has been verified. The method has been tested on real lidar signal from Wyoming Cloud Lidar (WCL). Results show that PFFTF has advantages over the other methods. It keeps the high frequency components well and reduces much of the random noise simultaneously for lidar signal processing. PMID:26473881

  6. Low-pass parabolic FFT filter for airborne and satellite lidar signal processing.

    PubMed

    Jiao, Zhongke; Liu, Bo; Liu, Enhai; Yue, Yongjian

    2015-10-14

    In order to reduce random errors of the lidar signal inversion, a low-pass parabolic fast Fourier transform filter (PFFTF) was introduced for noise elimination. A compact airborne Raman lidar system was studied, which applied PFFTF to process lidar signals. Mathematics and simulations of PFFTF along with low pass filters, sliding mean filter (SMF), median filter (MF), empirical mode decomposition (EMD) and wavelet transform (WT) were studied, and the practical engineering value of PFFTF for lidar signal processing has been verified. The method has been tested on real lidar signal from Wyoming Cloud Lidar (WCL). Results show that PFFTF has advantages over the other methods. It keeps the high frequency components well and reduces much of the random noise simultaneously for lidar signal processing.

  7. Low-Pass Parabolic FFT Filter for Airborne and Satellite Lidar Signal Processing

    PubMed Central

    Jiao, Zhongke; Liu, Bo; Liu, Enhai; Yue, Yongjian

    2015-01-01

    In order to reduce random errors of the lidar signal inversion, a low-pass parabolic fast Fourier transform filter (PFFTF) was introduced for noise elimination. A compact airborne Raman lidar system was studied, which applied PFFTF to process lidar signals. Mathematics and simulations of PFFTF along with low pass filters, sliding mean filter (SMF), median filter (MF), empirical mode decomposition (EMD) and wavelet transform (WT) were studied, and the practical engineering value of PFFTF for lidar signal processing has been verified. The method has been tested on real lidar signal from Wyoming Cloud Lidar (WCL). Results show that PFFTF has advantages over the other methods. It keeps the high frequency components well and reduces much of the random noise simultaneously for lidar signal processing. PMID:26473881

  8. Radioimmunotherapy with alpha-emitting nuclides.

    PubMed

    McDevitt, M R; Sgouros, G; Finn, R D; Humm, J L; Jurcic, J G; Larson, S M; Scheinberg, D A

    1998-09-01

    This review discusses the application of alpha particle-emitting radionuclides in targeted radioimmunotherapy. It will outline the production and chemistry of astatine-211, bismuth-212, lead-212, actinium-225, bismuth-213, fermium-255, radium-223 and terbium-149, which at present are the most promising alpha-emitting isotopes available for human clinical use. The selective cytotoxicity offered by alpha particle-emitting radioimmunoconstructs is due to the high linear energy transfer and short particle path length of these radionuclides. Based upon the pharmacokinetics of alpha particle-emitting radioimmunoconstructs, both stochastic and conventional dosimetric methodology is discussed, as is the preclinical and initial clinical use of these radionuclides conjugated to monoclonal antibodies for the treatment of human neoplasia. PMID:9724387

  9. E-Cigarettes Emit Toxic Vapors

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_160107.html E-Cigarettes Emit Toxic Vapors: Study Levels depend on ... findings could be important to both makers of e-cigarettes and regulators who want to reduce the ...

  10. Airborne 2-Micron Double-Pulsed Integrated Path Differential Absorption Lidar for Column CO2 Measurement

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta; Refaat, Tamer F.; Remus, Ruben G.; Fay, James J.; Reithmaier, Karl

    2014-01-01

    Double-pulse 2-micron lasers have been demonstrated with energy as high as 600 millijouls and up to 10 Hz repetition rate. The two laser pulses are separated by 200 microseconds and can be tuned and locked separately. Applying double-pulse laser in DIAL system enhances the CO2 measurement capability by increasing the overlap of the sampled volume between the on-line and off-line. To avoid detection complicity, integrated path differential absorption (IPDA) lidar provides higher signal-to-noise ratio measurement compared to conventional range-resolved DIAL. Rather than weak atmospheric scattering returns, IPDA rely on the much stronger hard target returns that is best suited for airborne platforms. In addition, the IPDA technique measures the total integrated column content from the instrument to the hard target but with weighting that can be tuned by the transmitter. Therefore, the transmitter could be tuned to weight the column measurement to the surface for optimum CO2 interaction studies or up to the free troposphere for optimum transport studies. Currently, NASA LaRC is developing and integrating a double-Pulsed 2-micron direct detection IPDA lidar for CO2 column measurement from an airborne platform. The presentation will describe the development of the 2-micron IPDA lidar system and present the airborne measurement of column CO2 and will compare to in-situ measurement for various ground target of different reflectivity.

  11. Airborne Hyperspectral Infrared Imaging Survey of the Southern San Andreas Fault

    NASA Astrophysics Data System (ADS)

    Lynch, D. K.; Tratt, D. M.; Buckland, K. N.; Johnson, P. D.

    2014-12-01

    The San Andreas Fault (SAF) between Desert Hot Springs and Bombay Beach has been surveyed with Mako, an airborne hyperspectral imager operating across the wavelength range 7.6-13.2 μm in the thermal-infrared (TIR) spectral region. The data were acquired with a 4-km swath width centered on the SAF, and many tectonic features are recorded in the imagery. Spectral analysis using diagnostic features of minerals can identify rocks, soils and vegetation. Mako imagery can also locate rupture zones and measure slip distances. Designed and built by The Aerospace Corporation, the innovative and highly capable airborne imaging spectrometer used for this work enables low-noise performance (NEΔT ≲ 0.1 K @ 10 μm) at small pixel IFOV (0.55 mrad) and high frame rates, making possible an area-coverage rate of 20 km2 per minute with 2-m ground resolution from 12,500 ft (3.8 km) above-ground altitude. Since its commissioning in 2010, Mako has been used in numerous studies involving other earthquake fault systems (Hector Mine, S. Bristol Mts.), mapping of surface geology, geothermal sources (fumaroles near the Salton Sea), urban surveys, and the detection, quantification, and tracking of natural and anthropogenic gaseous emission plumes. Mako is available for airborne field studies and new applications are of particular interest. It can be flown at any altitude below 20,000 ft to achieve the desired GSD.

  12. Atmospheric Airborne Pressure Measurements Using the Oxygen A Band for the ASCENDS Mission

    NASA Astrophysics Data System (ADS)

    Rodriguez, M.; Riris, H.; Abshire, J. B.; Allan, G. R.; Stephen, M.; Hasselbrack, W.; Mao, J.

    2012-12-01

    We report on airborne atmospheric pressure measurements using fiber-based laser technology and the oxygen A-band at 765 nm. Remote atmospheric temperature and pressure measurements are needed for NASA's Active Sensing of CO2 Emissions Over Nights, Days, and Seasons (ASCENDS) mission. ASCENDS will measure atmospheric CO2 dry mixing ratios on a global scale. Remote atmospheric pressure measurements are necessary to normalize ASCENDS CO2 measurements. Our work, funded by the ESTO IIP program, uses erbium doped fiber optic amplifiers and non-linear optics technology to tune laser radiation over the Oxygen A-band between 764.5 nm and 765 nm. Surface reflections are fiber-coupled from a receiver telescope to photon counting detectors. Our pulsed, time gated approach resolves ground reflections from cloud returns. This system successfully recorded O2 absorption spectra during two airborne campaigns aboard a NASA DC-8. Airborne data has been analyzed and fitted to HITRAN reference spectra based upon aircraft meteorological data. Our algorithm linearly scales the HITRAN reference until measurement errors are minimized. Atmospheric pressure changes are estimated by comparing the differential optical depth of the optimum scaled HITRAN spectra to the differential optical depth of the nominal HITRAN spectra. On flights over gradually sloping terrain, these results compare favorably with ground-based observations and predictions from computer models. Measurement uncertainty is commensurate with photon counting noise. We plan to reduce measurement uncertainty in future campaigns by improving transmitter pulse energy and increasing wavelength sweep frequency.

  13. Tropospheric Emission Spectrometer and Airborne Emission Spectrometer

    NASA Technical Reports Server (NTRS)

    Glavich, T.; Beer, R.

    1996-01-01

    The Tropospheric Emission Spectrometer (TES) is an instrument being developed for the NASA Earth Observing System Chemistry Platform. TES will measure the distribution of ozone and its precursors in the lower atmosphere. The Airborne Emission Spectrometer (AES) is an aircraft precursor to TES. Applicable descriptions are given of instrument design, technology challenges, implementation and operations for both.

  14. Simulation system of airborne FLIR searcher

    NASA Astrophysics Data System (ADS)

    Sun, Kefeng; Li, Yu; Gao, Jiaobo; Wang, Jun; Wang, Jilong; Xie, Junhu; Ding, Na; Sun, Dandan

    2014-11-01

    Airborne Forward looking infra-red (FLIR) searcher simulation system can provide multi-mode simulated test environment that almost actual field environment, and can simulate integrated performance and external interface of airborne FLIR simulation system. Furthermore, the airborne FLIR searcher simulation system can support the algorithm optimization of image processing, and support the test and evaluation of electro-optical system, and also support the line test of software and evaluate the performance of the avionics system. The detailed design structure and information cross-linking relationship of each component are given in this paper. The simulation system is composed of the simulation center, the FLIR actuator, the FLIR emulator, and the display control terminal. The simulation center can generate the simulated target and aircraft flying data in the operation state of the airborne FLIR Searcher. The FLIR actuator can provide simulation scene. It can generate the infrared target and landform based scanning scene, response to the commands from simulation center and the FLIR actuator and operation control unit. The infrared image generated by the FLIR actuator can be processed by the FLIR emulator using PowerPC hardware framework and processing software based on VxWorks system. It can detect multi-target and output the DVI video and the multi-target detection information which corresponds to the working state of the FLIR searcher. Display control terminal can display the multi-target detection information in two-dimension situation format, and realize human-computer interaction function.

  15. Toolsets for Airborne Data Beta Release

    Atmospheric Science Data Center

    2014-09-17

    ... for Airborne Data (TAD), developed at the Atmospheric Science Data Center (ASDC) at NASA Langley Research Center (LaRC) to promote ... and Houston, and DC3 will be added shortly. Early next year we plan to add DISCOVER-AQ Colorado and SEAC4RS to the TAD database. We ...

  16. A Technique for Airborne Aerobiological Sampling

    ERIC Educational Resources Information Center

    Mill, R. A.; And Others

    1972-01-01

    Report of a study of airborne micro-organisms collected over the Oklahoma City Metropolitan area and immediate environments, to investigate the possibility that a cloud of such organisms might account for the prevalence of some respiratory diseases in and around urban areas. (LK)

  17. Airborne Satcom Terminal Research at NASA Glenn

    NASA Technical Reports Server (NTRS)

    Hoder, Doug; Zakrajsek, Robert

    2002-01-01

    NASA Glenn has constructed an airborne Ku-band satellite terminal, which provides wideband full-duplex ground-aircraft communications. The terminal makes use of novel electronically-steered phased array antennas and provides IP connectivity to and from the ground. The satcom terminal communications equipment may be easily changed whenever a new configuration is required, enhancing the terminal's versatility.

  18. Observation of Shot Noise Suppression at Optical Wavelengths in a Relativistic Electron Beam

    SciTech Connect

    Ratner, Daniel; Stupakov, Gennady; /SLAC

    2012-06-19

    Control of collective properties of relativistic particles is increasingly important in modern accelerators. In particular, shot noise affects accelerator performance by driving instabilities or by competing with coherent processes. We present experimental observations of shot noise suppression in a relativistic beam at the Linac Coherent Light Source. By adjusting the dispersive strength of a chicane, we observe a decrease in the optical transition radiation emitted from a downstream foil. We show agreement between the experimental results, theoretical models, and 3D particle simulations.

  19. Stable blue phosphorescent organic light emitting devices

    SciTech Connect

    Forrest, Stephen R.; Thompson, Mark; Giebink, Noel

    2014-08-26

    Novel combination of materials and device architectures for organic light emitting devices is provided. An organic light emitting device, is provided, having an anode, a cathode, and an emissive layer disposed between the anode and the cathode. The emissive layer includes a host and a phosphorescent emissive dopant having a peak emissive wavelength less than 500 nm, and a radiative phosphorescent lifetime less than 1 microsecond. Preferably, the phosphorescent emissive dopant includes a ligand having a carbazole group.

  20. 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.

  1. CALIOPE airborne CO{sub 2} DIAL (CACDI) system design

    SciTech Connect

    Mietz, D.; Archuleta, B.; Archuleta, J.

    1997-09-01

    Los Alamos National Laboratory is currently developing an airborne CO{sub 2} Differential Absorption Lidar (DIAL) system based on second generation technology demonstrated last summer at NTS. The CALIOPE Airborne CO{sub 2} DIAL (CACDI) system requirements have been compiled based on the mission objectives and SONDIAL model trade studies. Subsystem designs have been developed based on flow down from these system requirements, as well as experience gained from second generation ground tests and N-ABLE (Non-proliferation AirBorne Lidar Experiments) airborne experiments. This paper presents the CACDI mission objectives, system requirements, the current subsystem design, and provides an overview of the airborne experimental plan.

  2. Shot noise from grain and particle impacts in Saturn's ring plane

    SciTech Connect

    Aubier, M.G.; Meyer-Vernet, N.; Petersen, B.M.

    1983-01-01

    The ring plane event detected by the Voyager 1 and 2 Planetary Radio Astronomy experiment is distinct from Saturn kilometric radiation (SKR) and from Saturn electrostatic discharges (SED). It consists of radio noise recorded only during Saturnian ring plane crossings. Several models are tested. The electrostatic noise on the antennas resulting from the passage of electrons and ions near the antennas (quasi-thermal noise) leads to order of magnitude much lower then the observed values. Shot noise due to electrons and ions collected and/or emitted by the antennas and spacecraft can explain the noise recorded during Saturn Voyager 1 ring plane crossing and partly what is observed in the case of Voyager 2. For this latter event we must introduce the shot noise due to grain impacts. A quantitative approach of this process gives an estimation of the dust size approx.2.3 ..mu..m just outside the G-ring.

  3. Vessel generator noise as a settlement cue for marine biofouling species.

    PubMed

    McDonald, J I; Wilkens, S L; Stanley, J A; Jeffs, A G

    2014-01-01

    Underwater noise is increasing globally, largely due to increased vessel numbers and international ocean trade. Vessels are also a major vector for translocation of non-indigenous marine species which can have serious implications for biosecurity. The possibility that underwater noise from fishing vessels may promote settlement of biofouling on hulls was investigated for the ascidian Ciona intestinalis. Spatial differences in biofouling appear to be correlated with spatial differences in the intensity and frequency of the noise emitted by the vessel's generator. This correlation was confirmed in laboratory experiments where C. intestinalis larvae showed significantly faster settlement and metamorphosis when exposed to the underwater noise produced by the vessel generator. Larval survival rates were also significantly higher in treatments exposed to vessel generator noise. Enhanced settlement attributable to vessel generator noise may indicate that vessels not only provide a suitable fouling substratum, but vessels running generators may be attracting larvae and enhancing their survival and growth.

  4. Regional airborne flux measurements in Europe

    NASA Astrophysics Data System (ADS)

    Gioli, B.; Miglietta, F.; Vaccari, F. P.; Zaldei, A.; Hutjes, R. W. A.

    2003-04-01

    The problem of identifying the spatial and temporal distribution of sources and sinks of atmospheric CO2 is the subject of considerable scientific and political debate. Even if it is now possible to estimate within reasonable accuracy the sink strength of European forests at the local scale, difficulties still exist in determining the partitioning of the sinks at the global and regional scales. The aim of the EU-project RECAB (Regional Assessment of the Carbon Balance in Europe) that is coordinated by Alterra, Wageningen (NL), is to bridge the gap between local scale flux measurements and continental scale inversion models by a generic modelling effort and measurement program, focussing on a limited number of selected regions in Europe for which previous measurements exists. This required the establishment of a European facility for airborne measurement of surface fluxes of CO2 at very low altitude, and a research aircraft capable of performing airborne eddy covariance measurements has been acquired by this project and used on several occasions at the different RECAB sites. The aircraft is the italian Sky Arrows ERA (Environmental Research Aircraft) equipped with the NOAA/ARA Mobile Flux Platform (MFP), and a commercial open-path infrared gas analyser. Airborne eddy covariance measurements were made from June 2001 onwards in Southern Spain near Valencia (June and December 2001), in Central Germany near Jena (July 2001), in Sweden near Uppsala (August 2001), in The Netherlands near Wageningen (January and July 2002) and in Italy near Rome (June 2002). Flux towers were present at each site to provide a validation of airborne eddy covariance measurements. This contribution reports some validation results based on the comparison between airborne and ground based flux measurements and some regional scale results for different locations and different seasons, in a wide range of meteorological and ecological settings.

  5. Airborne laser sensors and integrated systems

    NASA Astrophysics Data System (ADS)

    Sabatini, Roberto; Richardson, Mark A.; Gardi, Alessandro; Ramasamy, Subramanian

    2015-11-01

    The underlying principles and technologies enabling the design and operation of airborne laser sensors are introduced and a detailed review of state-of-the-art avionic systems for civil and military applications is presented. Airborne lasers including Light Detection and Ranging (LIDAR), Laser Range Finders (LRF), and Laser Weapon Systems (LWS) are extensively used today and new promising technologies are being explored. Most laser systems are active devices that operate in a manner very similar to microwave radars but at much higher frequencies (e.g., LIDAR and LRF). Other devices (e.g., laser target designators and beam-riders) are used to precisely direct Laser Guided Weapons (LGW) against ground targets. The integration of both functions is often encountered in modern military avionics navigation-attack systems. The beneficial effects of airborne lasers including the use of smaller components and remarkable angular resolution have resulted in a host of manned and unmanned aircraft applications. On the other hand, laser sensors performance are much more sensitive to the vagaries of the atmosphere and are thus generally restricted to shorter ranges than microwave systems. Hence it is of paramount importance to analyse the performance of laser sensors and systems in various weather and environmental conditions. Additionally, it is important to define airborne laser safety criteria, since several systems currently in service operate in the near infrared with considerable risk for the naked human eye. Therefore, appropriate methods for predicting and evaluating the performance of infrared laser sensors/systems are presented, taking into account laser safety issues. For aircraft experimental activities with laser systems, it is essential to define test requirements taking into account the specific conditions for operational employment of the systems in the intended scenarios and to verify the performance in realistic environments at the test ranges. To support the

  6. Underwater noise emissions from a drillship in the Arctic.

    PubMed

    Kyhn, Line A; Sveegaard, Signe; Tougaard, Jakob

    2014-09-15

    Wideband sound recordings were made of underwater noise emitted by an active drillship, Stena Forth, working in 484 m of water in Baffin Bay, western Greenland. The recordings were obtained at thirty and one-hundred meters depth. Noise was recorded during both drilling and maintenance work at ranges from 500 m to 38 km. The emitted noise levels were highest during maintenance work with estimated source levels up to 190 dB re 1 μPa (rms), while the source level during drilling was 184 dB re 1 μPa (rms). There were spectral peaks discernible from the background noise to ranges of at least 38 km from the drillship with the main energy below 3 kHz. M-weighted sound pressure levels were virtually identical to broadband levels for low-frequency cetaceans and about 5 dB lower for high-frequency cetaceans. Signals from the dynamic positioning system were clearly detectable at ranges up to two km from the drillship. PMID:25044041

  7. Disturbance caused by aircraft noise

    NASA Technical Reports Server (NTRS)

    Josse, R.

    1980-01-01

    Noise pollution caused by the presence of airfields adjacent to residential areas is studied. Noise effects on the sleep of residents near airports and the degree of the residents noise tolerance are evaluated. What aircraft noises are annoying and to what extent the annoyance varies with sound level are discussed.

  8. Making noise comfortable for people

    SciTech Connect

    Leventhall, H.G.; Wise, S.S.

    1998-10-01

    Typical HVAC noise may produce an uncomfortable environment, leading to the associated problems of general dissatisfaction and reduced productivity. It is not sufficient to have good thermal, lighting, and air cleanliness conditions if the noise is disturbing. In this paper, noise comfort is considered, with special emphasis on the developing criteria for low-frequency noise.

  9. Reducing environmental noise impacts: A USAREUR noise management program handbook

    NASA Astrophysics Data System (ADS)

    Feather, Timothy D.; Shekell, Ted K.

    1991-06-01

    Noise pollution is a major environmental problem faced by the U.S. Army in Europe. Noise-related complaints from German citizens can escalate into intense political issues in German communities. This in turn hampers efficient operation of military training and often times threatens the Army's mission. In order to remedy these problems, USAREUR has developed a noise management program. A successful noise management program will limit the impact of unavoidable noise on the populace. This report, a component of the noise management program, is a reference document for noise management planning. It contains guidelines and rules-of-thumb for noise management. This document contains procedures which operation and training level personnel can understand and apply in their day to day noise management planning. Noise mitigation tips are given. Basic technical information that will aid in understanding noise mitigation is provided along with noise management through land use planning. Noise management for specific components of the military community, (airfields, base operations, training areas, and housing and recreation areas) are addressed. The nature of noise generated, means of noise abatement at the source, path, and receiver (both physical and organizational/public relations methods), and a case study example are described.

  10. The Beginnings of Airborne Astronomy, 1920 - 1930: an Historical Narrative

    NASA Technical Reports Server (NTRS)

    Craine, E. R.

    1984-01-01

    The emergence of airborne astronomy in the early twentieth century is recounted. The aerial expedition to observe the solar eclipse on September 10, 1923, is described. Observation of the total solar eclipse of January 24, 1925, is discussed. The Honey Lake aerial expedition to study the solar eclipse of April 28, 1930, is also described. Four major accomplishments in airborne astronomy during the period 1920 to 1930 are listed. Airborne expeditions were undertaken at every logical opportunity, starting a continuous sequence of airborne astronomical expeditions which was to remain unbroken, except by World War II, to the present day. Although the scientific returns of the first ten years were modest, they did exist. Interest in, and support for, airborne astronomy was generated not only among astronomers but also among the public. Albert Stevens, arguably the true father of airborne astronomy, was to become interested in applying his considerable skill and experience to the airborne acquisition of astronomical data.

  11. Modeling of broadband airborne electromagnetic responses from saline environments

    SciTech Connect

    Buselli, G.; Williamson, D.R.

    1996-11-01

    The removal of vegetation for the development of nonirrigated agriculture and the associated increase in groundwater recharge and discharge has caused significant areas of salinization of surface soil and water resources in Australia. At least three types of salt profiles are known to indicate the relative magnitude of recharge. These profiles may be differentiated by their resistivity structure. Since a broadband airborne electromagnetic (AEM) method offers the possibility of readily obtaining resistivity soundings, modeling was carried out to investigate the ability of a broadband AEM system to distinguish different salt profile types. Salt profile types may be represented by a four-layer resistivity model. The use of a broadband AEM system to distinguish the relative magnitude of the resistivity of a layer of high salt accumulation and the underlying layer forms the basis for efficiently identifying areas of high or low recharge. Where the resistivity of the underlying layer is greater than that of the salt accumulation, high recharge is indicated, and a lower resistivity of this layer implies low recharge. The response of each of the salt profile models was calculated in the frequency domain and then inverted back to a layered model. With noise added to the calculated responses, the inversion results show that the depth, thickness, and resistivity of a layer of high salt accumulation can be resolved by AEM measurements. Furthermore, the resistivity of this layer can be distinguished from the resistivity of the underlying layer.

  12. Quantitative interpretation of airborne gravity gradiometry data for mineral exploration

    NASA Astrophysics Data System (ADS)

    Martinez, Cericia D.

    In the past two decades, commercialization of previously classified instrumentation has provided the ability to rapidly collect quality gravity gradient measurements for resource exploration. In the near future, next-generation instrumentation are expected to further advance acquisition of higher-quality data not subject to pre-processing regulations. Conversely, the ability to process and interpret gravity gradiometry data has not kept pace with innovations occurring in data acquisition systems. The purpose of the research presented in this thesis is to contribute to the understanding, development, and application of processing and interpretation techniques available for airborne gravity gradiometry in resource exploration. In particular, this research focuses on the utility of 3D inversion of gravity gradiometry for interpretation purposes. Towards this goal, I investigate the requisite components for an integrated interpretation workflow. In addition to practical 3D inversions, components of the workflow include estimation of density for terrain correction, processing of multi-component data using equivalent source for denoising, quantification of noise level, and component conversion. The objective is to produce high quality density distributions for subsequent geological interpretation. I then investigate the use of the inverted density model in orebody imaging, lithology differentiation, and resource evaluation. The systematic and sequential approach highlighted in the thesis addresses some of the challenges facing the use of gravity gradiometry as an exploration tool, while elucidating a procedure for incorporating gravity gradient interpretations into the lifecycle of not only resource exploration, but also resource modeling.

  13. Hydrogeophysics at the watershed-scale using airborne electromagnetics

    NASA Astrophysics Data System (ADS)

    Minsley, B. J.; Abraham, J. D.; Bedrosian, P. A.; Cannia, J. C.; Smith, B. D.

    2011-12-01

    Airborne electromagnetic (AEM) surveys provide densely sampled data over large areas (typically several hundred sq. km) that cannot be covered effectively using ground-based methods. AEM data are inverted to infer the distribution of electrical resistivity structures from shallow depths to several hundred meters. These models convey unparalleled details that are used to make inferences about hydrogeologic properties and processes at the watershed-scale. This information is being used in groundwater models that inform water management decisions, to better understand geologic frameworks, and to improve climate change models. We present the results of frequency-domain AEM surveys acquired by the US Geological Survey that have been used for building hydrogeologic frameworks in Nebraska, and understanding permafrost distributions in Alaska. An important aspect of interpreting the AEM data in a hydrogeologic context involves quantifying uncertainty and understanding the constraints on subsurface properties provided by the measured geophysical data. To achieve this, we present a trans-dimensional Bayesian Markov chain Monte Carlo (MCMC) algorithm that samples the distribution of models consistent with the measured data. Assessing the distribution of plausible models, rather than a single 'best-fit' model, provides valuable details about parameter uncertainty and non-uniqueness that leads to a more robust interpretation. In addition, we show how the MCMC algorithm can be used to evaluate the noise level in the measured data as well as errors in the elevation of the AEM system, both of which influence the space of acceptable models.

  14. Detector noise statistics in the non-linear regime

    NASA Technical Reports Server (NTRS)

    Shopbell, P. L.; Bland-Hawthorn, J.

    1992-01-01

    The statistical behavior of an idealized linear detector in the presence of threshold and saturation levels is examined. It is assumed that the noise is governed by the statistical fluctuations in the number of photons emitted by the source during an exposure. Since physical detectors cannot have infinite dynamic range, our model illustrates that all devices have non-linear regimes, particularly at high count rates. The primary effect is a decrease in the statistical variance about the mean signal due to a portion of the expected noise distribution being removed via clipping. Higher order statistical moments are also examined, in particular, skewness and kurtosis. In principle, the expected distortion in the detector noise characteristics can be calibrated using flatfield observations with count rates matched to the observations. For this purpose, some basic statistical methods that utilize Fourier analysis techniques are described.

  15. Validating MODIS above-cloud aerosol optical depth retrieved from "color ratio" algorithm using direct measurements made by NASA's airborne AATS and 4STAR sensors

    NASA Astrophysics Data System (ADS)

    Jethva, Hiren; Torres, Omar; Remer, Lorraine; Redemann, Jens; Livingston, John; Dunagan, Stephen; Shinozuka, Yohei; Kacenelenbogen, Meloe; Segal Rosenheimer, Michal; Spurr, Rob

    2016-10-01

    We present the validation analysis of above-cloud aerosol optical depth (ACAOD) retrieved from the "color ratio" method applied to MODIS cloudy-sky reflectance measurements using the limited direct measurements made by NASA's airborne Ames Airborne Tracking Sunphotometer (AATS) and Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) sensors. A thorough search of the airborne database collection revealed a total of five significant events in which an airborne sun photometer, coincident with the MODIS overpass, observed partially absorbing aerosols emitted from agricultural biomass burning, dust, and wildfires over a low-level cloud deck during SAFARI-2000, ACE-ASIA 2001, and SEAC4RS 2013 campaigns, respectively. The co-located satellite-airborne matchups revealed a good agreement (root-mean-square difference < 0.1), with most matchups falling within the estimated uncertainties associated the MODIS retrievals (about -10 to +50 %). The co-retrieved cloud optical depth was comparable to that of the MODIS operational cloud product for ACE-ASIA and SEAC4RS, however, higher by 30-50 % for the SAFARI-2000 case study. The reason for this discrepancy could be attributed to the distinct aerosol optical properties encountered during respective campaigns. A brief discussion on the sources of uncertainty in the satellite-based ACAOD retrieval and co-location procedure is presented. Field experiments dedicated to making direct measurements of aerosols above cloud are needed for the extensive validation of satellite-based retrievals.

  16. Why use noise?

    PubMed

    Pelli, D G; Farell, B

    1999-03-01

    Measuring the dependence of visual sensitivity on parameters of the visual stimulus is a mainstay of vision science. However, it is not widely appreciated that visual sensitivity is a product of two factors that are each invariant with respect to many properties of the stimulus and task. By estimating these two factors, one can isolate visual processes more easily than by using sensitivity measures alone. The underlying idea is that noise limits all forms of communication, including vision. As an empirical matter, it is often useful to measure the human observer's threshold with and without a noise background added to the display, to disentangle the observer's ability from the observer's intrinsic noise. And when we know how much noise there is, it is often useful to calculate ideal performance of the task at hand, as a benchmark for human performance. This strips away the intrinsic difficulty of the task to reveal a pure measure of human ability. Here we show how to do the factoring of sensitivity into efficiency and equivalent noise, and we document the invariances of the two factors.

  17. Aircraft noise synthesis system

    NASA Technical Reports Server (NTRS)

    Mccurdy, David A.; Grandle, Robert E.

    1987-01-01

    A second-generation Aircraft Noise Synthesis System has been developed to provide test stimuli for studies of community annoyance to aircraft flyover noise. The computer-based system generates realistic, time-varying, audio simulations of aircraft flyover noise at a specified observer location on the ground. The synthesis takes into account the time-varying aircraft position relative to the observer; specified reference spectra consisting of broadband, narrowband, and pure-tone components; directivity patterns; Doppler shift; atmospheric effects; and ground effects. These parameters can be specified and controlled in such a way as to generate stimuli in which certain noise characteristics, such as duration or tonal content, are independently varied, while the remaining characteristics, such as broadband content, are held constant. The system can also generate simulations of the predicted noise characteristics of future aircraft. A description of the synthesis system and a discussion of the algorithms and methods used to generate the simulations are provided. An appendix describing the input data and providing user instructions is also included.

  18. Transmission noise identification using two-dimensional dynamic signal analysis

    NASA Astrophysics Data System (ADS)

    Pan, Min-Chun; Chen, Jeng-Xin

    2003-04-01

    This study aims at identifying transmission noise of two types of electrical vehicles with different transmission systems using the developed two-dimensional dynamic signal analysis (2DSA). Two electrical scooters, more specifically, with a gear transmission system and a continuous variable transmission (CVT) system, respectively, have been taken as test benches due to the whistle-like noise emitting from their transmission systems. To effectively process dynamic signatures measured from rotary machinery with varying speed, and even varying orders during operation, such as a machine with a CVT system or gear-shifting operation, the 2DSA approaches including the order analysis (OA) and the time-frequency analysis have been developed and implemented as processing tools. The specifications of vehicle transmission systems, especially the ratio of each speed reduction, and the tooth (cog, blade, etc.) number of transmission elements, i.e., geometric analysis, are firstly to be examined. After the 2DSA processes the noise measured from test vehicles during wide-open-throttle operation, dominant annoying transmission noise components can be extracted, and their sources can be identified through comparing feature orders obtained from geometric analysis. The procedure can not only identify noise sources but conclude transmission components to be further modified in respect of annoying noise.

  19. Passive synthetic aperture imaging with limited noise sources

    NASA Astrophysics Data System (ADS)

    Garnier, Josselin

    2016-09-01

    We consider a passive synthetic aperture imaging problem. A single moving receiver antenna records random signals generated by one or several distant noise sources and backscattered by one or several reflectors. The sources emit noise signals modeled by stationary random processes. The reflectors can be imaged by summing the autocorrelation functions of the received signals computed over successive time windows, corrected for Doppler factors and migrated by appropriate travel times. In particular, the Doppler effect plays an important role and it can be used for resolution enhancement. When the noise source positions are not known, the reflector can be localized with an accuracy proportional to the reciprocal of the noise bandwidth, even when only a very small number of sources are available. When the noise source positions are known, the reflector can be localized with a cross range resolution proportional to the carrier wavelength and inversely proportional to the length of the receiver trajectory (i.e. the synthetic aperture), and with a range resolution proportional to the reciprocal of the bandwidth, even with only one noise source.

  20. Noise Control for a Moving Evaluation Point Using Neural Networks

    NASA Astrophysics Data System (ADS)

    Maeda, Toshiki; Shiraishi, Toshihiko

    2016-09-01

    This paper describes the noise control for a moving evaluation point using neural networks by making the best use of its learning ability. Noise control is a technology which is effective on low-frequency noise. Based on the principle of superposition, a primary sound wave can be cancelled at an evaluation point by emitting a secondary opposite sound wave. To obtain good control performance, it is important to precisely identify the characteristics of all the sound paths. One of the most popular algorithms of noise control is filtered-x LMS algorithm. This algorithm can deliver a good result while all the sound paths do not change. However, the control system becomes uncontrollable while the evaluation point is moving. To solve the problem, the characteristics of all the paths are must be identified at all time. In this paper, we applied neural networks with the learning ability to the noise control system to follow the time-varying paths and verified its control performance by numerical simulations. Then, dropout technique for the networks is also applied. Dropout is a technique that prevent the network from overfitting and enables better control performance. By applying dropout for noise control, it prevents the system from diverging.

  1. How to Evaluate the Electric Noise in a Cell Membrane?

    NASA Astrophysics Data System (ADS)

    Bier, M.

    2006-05-01

    There has been considerable public anxiety about possible health effects of electromagnetic radiation emitted by high voltage power lines. Power frequencies (60 Hz in the US, 50 Hz in many other countries) are sufficiently slow for the associated electric fields to distribute themselves across the highly resistive cell membranes. To assess the ambient power frequency fields, researchers have compared the voltage that these fields induce across cell membranes to the strength of the electric noise that the membranes generate themselves through Brownian motion. However, there has been disagreement among researchers on how to evaluate this equilibrium membrane electric noise. I will review the different approaches and present an {ITALIC ab initio} modeling of membrane electric fields. I will show that different manifestations of Brownian noise lead to an electric noise intensity that is many times larger than what conventional estimates have yielded. Next, the legitimacy of gauging a nonequilibrium external signal against internal equilibrium noise is questioned and a more meaningful criterion is proposed. Finally, an estimate will be derived of the nonequilibrium noise intensity due to the driven ion traffic through randomly opening and closing ion channels.

  2. Rotor noise in maneuvering flight

    NASA Astrophysics Data System (ADS)

    Chen, Hsuan-Nien

    The objective of this research is to understand the physics of rotor noise in the maneuvering flight. To achieve this objective, an integrated noise prediction system is constructed, namely GenHel-MFW-PSU-WOPWOP. This noise prediction system includes a flight simulation code, a high fidelity free vortex-wake code, and a rotor acoustic prediction code. By using this noise prediction system, rotor maneuver noise characteristics are identified. Unlike periodic rotor noise, a longer duration is required to describe rotor maneuver noise. The variation of helicopter motion, blade motion and blade airloads are all influencing the noise prediction results in both noise level and directivity in the maneuvering flight. In this research, two types of rotor maneuver noise are identified, steady maneuver noise and transient maneuver noise. In the steady maneuver, rotor noise corresponds to a steady maneuver condition, which has nearly steady properties in flight dynamics and aerodynamics. Transient maneuver noise is the result of the transition between two steady maneuvers. In a transient maneuver, the helicopter experiences fluctuations in airload and helicopter angular rates, which lead to excess rotor noise. Even though the transient maneuver only exists for a fairly short period of time, the corresponding transient maneuver noise could be significant when compared to steady maneuver noise. The blade tip vortices also present complex behaviors in the transient maneuver condition. With stronger vortex circulation strength and the potential for vortex bundling, blade vortex-interaction (BVI) noise may increase significantly during a transient maneuver. In this research, it is shown that even with small pilot controls, significant BVI noise can be generated during a transient flight condition. Finally, through this research, the importance of transient maneuver noise is demonstrated and recognized.

  3. Latest Advancement In Airborne Relative Gravity Instrumentation.

    NASA Astrophysics Data System (ADS)

    Brady, N.

    2011-12-01

    Airborne gravity surveying has been performed with widely varying degrees of success since early experimentation with the Lacoste and Romberg dynamic meter in the 1950s. There are a number of different survey systems currently in operation including relative gravity meters and gradiometers. Airborne gravity is ideally suited to rapid, wide coverage surveying and is not significantly more expensive in more remote and inhospitable terrain which makes airborne measurements one of the few viable options available for cost effective exploration. As improved instrumentation has become available, scientific applications have also been able to take advantage for use in determining sub surface geologic structures, for example under ice sheets in Antarctica, and more recently direct measurement of the geoid to improve the vertical datum in the United States. In 2004, Lacoste and Romberg (now Micro-g Lacoste) decided to build on their success with the newly developed AirSea II dynamic meter and use that system as the basis for a dedicated airborne gravity instrument. Advances in electronics, timing and positioning technology created the opportunity to refine both the hardware and software, and to develop a truly turnkey system that would work well for users with little or no airborne gravity experience as well as those with more extensive experience. The resulting Turnkey Airborne Gravity System (TAGS) was successfully introduced in 2007 and has since been flown in applications from oil, gas and mineral exploration surveys to regional gravity mapping and geoid mapping. The system has been mounted in a variety of airborne platforms including depending on the application of interest. The development experience with the TAGS enabled Micro-g Lacoste to embark on a new project in 2010 to completely redesign the mechanical and electronic components of the system rather than continuing incremental upgrades. Building on the capabilities of the original TAGS, the objectives for the

  4. Comparison of Retracking Algorithms Using Airborne Radar and Laser Altimeter Measurements of the Greenland Ice Sheet

    NASA Technical Reports Server (NTRS)

    Ferraro, Ellen J.; Swift, Calvin T.

    1995-01-01

    This paper compares four continental ice sheet radar altimeter retracking algorithms using airborne radar and laser altimeter data taken over the Greenland ice sheet in 1991. The refurbished Advanced Application Flight Experiment (AAFE) airborne radar altimeter has a large range window and stores the entire return waveform during flight. Once the return waveforms are retracked, or post-processed to obtain the most accurate altitude measurement possible, they are compared with the high-precision Airborne Oceanographic Lidar (AOL) altimeter measurements. The AAFE waveforms show evidence of varying degrees of both surface and volume scattering from different regions of the Greenland ice sheet. The AOL laser altimeter, however, obtains a return only from the surface of the ice sheet. Retracking altimeter waveforms with a surface scattering model results in a good correlation with the laser measurements in the wet and dry-snow zones, but in the percolation region of the ice sheet, the deviation between the two data sets is large due to the effects of subsurface and volume scattering. The Martin et al model results in a lower bias than the surface scattering model, but still shows an increase in the noise level in the percolation zone. Using an Offset Center of Gravity algorithm to retrack altimeter waveforms results in measurements that are only slightly affected by subsurface and volume scattering and, despite a higher bias, this algorithm works well in all regions of the ice sheet. A cubic spline provides retracked altitudes that agree with AOL measurements over all regions of Greenland. This method is not sensitive to changes in the scattering mechanisms of the ice sheet and it has the lowest noise level and bias of all the retracking methods presented.

  5. Aircraft turbofan noise

    NASA Technical Reports Server (NTRS)

    Groeneweg, J. F.; Rice, E. J.

    1983-01-01

    Turbofan noise generation and suppression in aircraft engines are reviewed. The chain of physical processes which connect unsteady flow interactions with fan blades to far field noise is addressed. Mechanism identification and description, duct propagation, radiation and acoustic suppression are discussed. The experimental technique of fan inflow static tests are discussed. Rotor blade surface pressure and wake velocity measurements aid in the determination of the types and strengths of the generation mechanisms. Approaches to predicting or measuring acoustic mode content, optimizing treatment impedance to maximize attenuation, translating impedance into porous wall structure and interpreting far field directivity patterns are illustrated by comparisons of analytical and experimental results. The interdependence of source and acoustic treatment design to minimize far field noise is emphasized. Area requiring further research are discussed and the relevance of aircraft turbofan results to quieting other turbomachinery installations is addressed.

  6. Road Traffic Noise

    NASA Astrophysics Data System (ADS)

    Beckenbauer, Thomas

    Road traffic is the most interfering noise source in developed countries. According to a publication of the European Union (EU) at the end of the twentieth century [1], about 40% of the population in 15 EU member states is exposed to road traffic noise at mean levels exceeding 55 dB(A). Nearly 80 million people, 20% of the population, are exposed to levels exceeding 65 dB(A) during daytime and more than 30% of the population is exposed to levels exceeding 55 dB(A) during night time. Such high noise levels cause health risks and social disorders (aggressiveness, protest, and helplessness), interference of communication and disturbance of sleep; the long- and short-term consequences cause adverse cardiovascular effects, detrimental hormonal responses (stress hormones), and possible disturbance of the human metabolism (nutrition) and the immune system. Even performance at work and school could be impaired.

  7. [Noise in fishing vessels].

    PubMed

    Peretti, Alessandro; Nataletti, Pietro; Bonfiglio, Paolo; di Bisceglie, Anita Pasqua

    2013-01-01

    The present research concerns the noise analysis of five vessels during navigation and fishing activities. In locations where staff operates, sound levels (produced substantially by the engine) were close to 90 dB(A); within the rest areas the noise is also quite significant. On the basis of working time, exposure levels ranged between 80 and 90 dB(A). In order to identify interventions able to reduce the risk, reverberation times, sound insulation of the different areas and the vibrations produced by the engine were measured on the same vessels docked in port. Noise level reduction as a result of sound absorptive treatments were estimated using an analytical model. PMID:24303698

  8. Aircraft turbofan noise

    NASA Astrophysics Data System (ADS)

    Groeneweg, J. F.; Rice, E. J.

    1987-01-01

    Turbofan noise generation and suppression in aircraft engines are reviewed. The chain of physical processes which connect unsteady flow interactions with fan blades to far field noise is addressed. Mechanism identification and description, duct propagation, radiation, and acoustic suppression are discussed. The experimental techniques of fan inflow static tests are discussed. Rotor blade surface pressure and wake velocity measurements aid in the determination of the types and strengths of the generation mechanisms. Approaches to predicting or measuring acoustic mode content, optimizing treatment impedance to maximize attenuation, translating impedance into porous wall structure, and interpreting far field directivity patterns are illustrated by comparisons of analytical and experimental results. The interdependence of source and acoustic treatment design to minimize far field noise is emphasized. Areas requiring further research are discussed, and the relevance of aircraft turbofan results to quieting other turbomachinery installation is addressed.

  9. Aircraft turbofan noise

    NASA Astrophysics Data System (ADS)

    Groeneweg, J. F.; Rice, E. J.

    1983-03-01

    Turbofan noise generation and suppression in aircraft engines are reviewed. The chain of physical processes which connect unsteady flow interactions with fan blades to far field noise is addressed. Mechanism identification and description, duct propagation, radiation and acoustic suppression are discussed. The experimental technique of fan inflow static tests are discussed. Rotor blade surface pressure and wake velocity measurements aid in the determination of the types and strengths of the generation mechanisms. Approaches to predicting or measuring acoustic mode content, optimizing treatment impedance to maximize attenuation, translating impedance into porous wall structure and interpreting far field directivity patterns are illustrated by comparisons of analytical and experimental results. The interdependence of source and acoustic treatment design to minimize far field noise is emphasized. Area requiring further research are discussed and the relevance of aircraft turbofan results to quieting other turbomachinery installations is addressed.

  10. How to Map Noise.

    PubMed

    Hinton, John

    2002-01-01

    Noise mapping is a method of presenting complex noise information in a clear and simple way either on a physical map or in a database. This mapping information can be either calculated or measured using a variety of techniques and methods. Furthermore, the results of such exercises can be presented in many different ways and used for a number of different purposes. This paper attempts to examine these issues in the light of the "mapping requirements" outlined in the recently proposed Directive of the European Parliament and of the Council, relating to the Assessment and Management of Environmental Noise (Comm (2000) 468 final). This proposed Directive was laid before the Parliament and Council in the autumn of 2000. The First Reading of the proposal was successfully negotiated just before Christmas 2000. The Second Reading is likely to commence shortly.

  11. Modeling and Validation of Damped Plexiglas Windows for Noise Control

    NASA Technical Reports Server (NTRS)

    Buehrle, Ralph D.; Gibbs, Gary P.; Klos, Jacob; Mazur, Marina

    2003-01-01

    Windows are a significant path for structure-borne and air-borne noise transmission in general aviation aircraft. In this paper, numerical and experimental results are used to evaluate damped plexiglas windows for the reduction of structure-borne and air-borne noise transmitted into the interior of an aircraft. In contrast to conventional homogeneous windows, the damped plexiglas windows were fabricated using two or three layers of plexiglas with transparent viscoelastic damping material sandwiched between the layers. Transmission loss and radiated sound power measurements were used to compare different layups of the damped plexiglas windows with uniform windows of the same nominal thickness. This vibro-acoustic test data was also used for the verification and validation of finite element and boundary element models of the damped plexiglas windows. Numerical models are presented for the prediction of radiated sound power for a point force excitation and transmission loss for diffuse acoustic excitation. Radiated sound power and transmission loss predictions are in good agreement with experimental data. Once validated, the numerical models were used to perform a parametric study to determine the optimum configuration of the damped plexiglas windows for reducing the radiated sound power for a point force excitation.

  12. The potential of a new air cleaner to reduce airborne microorganisms in pig house air: preliminary results.

    PubMed

    Schulz, Jochen; Bao, Endong; Clauss, Marcus; Hartung, Jörg

    2013-01-01

    There is a need for technical solutions to reduce the concentrations of bioaerosols in the air and in the exhaust air of livestock buildings. A prototype of an air washer combined with a UV-irradiation system was positioned in a commercial pig fattening unit to test its efficiency of reducing culturable airborne microorganisms. No significant reduction in airborne bacteria and fungi was observed when untreated air passed through the device. However, when the air washer or the UV-irradiation system was activated, the concentrations of mesophilic aerobic bacteria, methicillin resistant Staphylococcus aureus and mesophilic aerotolerant cocci were reduced significantly (p < 0.01). Washing the air reduced bacteria by 84 to 96% and the relative reduction due to UV-irradiation ranged between 55 and 90%. The highest relative reduction in airborne bacteria (90 to 99%) was detected when the air washer and the UV-irradiation systems were in simultaneous operation. The concentration of total airborne fungi was reduced significantly (p < 0.05) only when the air was washed and UV-irradiated. Although these preliminary results provided significant and comprehensible findings, long-term studies are required to assess the efficiency of the device in more detail.The combination of air washing and UV-irradiation seem to be a useful technique for abating airborne microorganisms within or emitting from piggery buildings. However, some technical problems remain, such as the deposition of particulate matter on the surface of UV-irradiators and the consumption of fresh water by the air washer. These issues must be resolved before the system may be implemented for general practice. PMID:23540197

  13. Mapping of noise impact provoked by the execution of foundation piles at high rise building sites.

    PubMed

    de Araújo, Adolpho Guido; Gusmão, Alexandre Duarte; Rabbani, Emilia Rahnemay Kohman; Fucale, Stela Paulino

    2012-01-01

    The objective of this work is to map, in a limited area inside and outside of the worksite, the environmental impact generated by sound pollution coming from the driving of foundation piles for high rise buildings, as well as to observe and check if the noise levels produced by the emitting source are tolerable in the urban environment. The methodology of the work includes a survey of technical references about the subject; measurement of noises surrounding the worksite during the foundation phase for four distinct buildings, with different types of piles: prefabricated piles, continuous helical displacement piles , traditional compaction piles and Terra Probe compaction piles. A grid of points was built due to the time of driving and after that the measurements of environmental noises were performed emitted by the execution of each type of pile using a sound level meter. The interpretation of the measurements and their impacts on the neighborhood of the building were performed using the computational tool Suffer for creating noise level contours. The X and Y axes of the grid represent the distances in meters of the area studied and the Z axis represents the noise measured in dB. The contours developed represent the mapping of the noise at the worksites and their surroundings. The mapping of the urban impact of noise, the measurement of its dimensions, and the examination of its propagation around the building are important subsides to adequate individual and collective protection procedures. Seventy one points were measured at four building sites with different types of piles, and the results showed that at only three points was the noise within the limits of the Municipal Law of Recife of 70 dB, which proves the relevance of the research. Finally, the comparative analysis between the four types of piles shows that the continuous helical displacement pile emits the lowest noise level among the four pile types studied.

  14. Mapping of noise impact provoked by the execution of foundation piles at high rise building sites.

    PubMed

    de Araújo, Adolpho Guido; Gusmão, Alexandre Duarte; Rabbani, Emilia Rahnemay Kohman; Fucale, Stela Paulino

    2012-01-01

    The objective of this work is to map, in a limited area inside and outside of the worksite, the environmental impact generated by sound pollution coming from the driving of foundation piles for high rise buildings, as well as to observe and check if the noise levels produced by the emitting source are tolerable in the urban environment. The methodology of the work includes a survey of technical references about the subject; measurement of noises surrounding the worksite during the foundation phase for four distinct buildings, with different types of piles: prefabricated piles, continuous helical displacement piles , traditional compaction piles and Terra Probe compaction piles. A grid of points was built due to the time of driving and after that the measurements of environmental noises were performed emitted by the execution of each type of pile using a sound level meter. The interpretation of the measurements and their impacts on the neighborhood of the building were performed using the computational tool Suffer for creating noise level contours. The X and Y axes of the grid represent the distances in meters of the area studied and the Z axis represents the noise measured in dB. The contours developed represent the mapping of the noise at the worksites and their surroundings. The mapping of the urban impact of noise, the measurement of its dimensions, and the examination of its propagation around the building are important subsides to adequate individual and collective protection procedures. Seventy one points were measured at four building sites with different types of piles, and the results showed that at only three points was the noise within the limits of the Municipal Law of Recife of 70 dB, which proves the relevance of the research. Finally, the comparative analysis between the four types of piles shows that the continuous helical displacement pile emits the lowest noise level among the four pile types studied. PMID:22317218

  15. Brontides: natural explosive noises.

    PubMed

    Gold, T; Soter, S

    1979-04-27

    Episodes of explosive noises of natural origin, or brontides, have been well documented, often in association with seismic activity and in a few cases as precursors to major earthquakes. Ground-to-air acoustic transmission from shallow earthquakes can account for many of these episodes, but not for all, and other causes, such as the sudden eruption of gas from high-pressure sources in the ground may at times have been responsible. Confusion with distant thunder or artillery at times of anomalous sound propagation complicates the analysis, and more recently the greatly increased frequency of artificial explosive noises and sonic booms has tended to mask the recognition of natural brontides. PMID:17757998

  16. Comparator With Noise Suppression

    NASA Technical Reports Server (NTRS)

    Batts, C. N.

    1985-01-01

    Comparator continuously and automatically adjusts noise immunity period. High-gain amplifier used in conjunction with multivibrator 4 to provide clear pulse to multivibrator 1 at first negative-going zero crossing of input signal. Once multivibrator 1 cleared, output goes to zero volts and not retriggered until next time positive input exceeds reference level. Since input signal noise at zero crossing does not exceed reference level, no effect on multivibrator 1 operation. Circuit fabricated using standard solid-state operational amplifiers, multivibrators, OR gates, and passive elements.

  17. Side-emitting fiber optic position sensor

    DOEpatents

    Weiss, Jonathan D.

    2008-02-12

    A side-emitting fiber optic position sensor and method of determining an unknown position of an object by using the sensor. In one embodiment, a concentrated beam of light source illuminates the side of a side-emitting fiber optic at an unknown axial position along the fiber's length. Some of this side-illuminated light is in-scattered into the fiber and captured. As the captured light is guided down the fiber, its intensity decreases due to loss from side-emission away from the fiber and from bulk absorption within the fiber. By measuring the intensity of light emitted from one (or both) ends of the fiber with a photodetector(s), the axial position of the light source is determined by comparing the photodetector's signal to a calibrated response curve, look-up table, or by using a mathematical model. Alternatively, the side-emitting fiber is illuminated at one end, while a photodetector measures the intensity of light emitted from the side of the fiber, at an unknown position. As the photodetector moves further away from the illuminated end, the detector's signal strength decreases due to loss from side-emission and/or bulk absorption. As before, the detector's signal is correlated to a unique position along the fiber.

  18. Low Noise Amplifiers and Receivers for Remote Sensing

    NASA Technical Reports Server (NTRS)

    Kangaslahti, Pekka; Lim, Boon; Gaier, Todd; Tanner, Alan; Varonen, Mikko; Samoska, Lorene; Brown, Shannon; Lambrigtsen, Bjorn; Reising, Steven; Tanabe, Jordan; Montes, Oliver; Dawson, Douglas; Parashare, Chaitali

    2011-01-01

    The study of atmospheric dynamics and climatology depend on accurate and frequent measurements of temperature and humidity profiles of the atmosphere. These measurements furthermore enable highly accurate measurements of ocean topography by providing total column water vapour data for radar path delay correction. The atmospheric temperature profile is characterised at the oxygen molecule absorption frequencies (60 and 118 GHz) and the humidity profile at the water molecule absorption frequencies (23 and 183 GHz). Total column measurements can be achieved by comparing measured radiometric temperatures at atmospheric window channels, such as 90, 130 and 166 GHz. The standard receiver technology for these frequencies was diode mixers with MMIC LNAs being applied at the lower frequencies. The sensitivity of millimetre wave receivers improved significantly with the introduction of the low noise 35 nm gate length InP MMIC amplifiers. We currently achieve 3 dB noise figure at 180 GHz and 2 dB noise figure at 90 GHz with our MMIC low noise amplifiers (LNAs) in room temperature. These amplifiers and the receivers we have built using them made it possible to conduct highly accurate airborne measurement campaigns from the Global Hawk unmanned aerial vehicle, develop millimeter wave internally calibrated radiometers for altimeter radar path delay correction, and build prototypes of large arrays of millimeter receivers for a geostationary interferometric sounder. We use the developed millimeter wave receivers to measure temperature and humidity profiles in the atmosphere and in hurricanes as well as to characterize the path delay error in ocean topography altimetry.

  19. Low Noise Amplifiers and Receivers for Remote Sensing

    NASA Technical Reports Server (NTRS)

    Kangaslahti, Pekka; Lim, Boon; Gaier, Todd; Tanner, Alan; Varonen, Mikko; Samoska, Lorene; Brown, Shannon; Lambrigsten, Bjorn; Reising, Steven; Tanabe, Jordan; Montes, Oliver; Dawson, Douglas; Parashare, Chaitali

    2012-01-01

    The study of atmospheric dynamics and climatology depend on accurate and frequent measurements of temperature and humidity profiles of the atmosphere. These measurements furthermore enable highly accurate measurements of ocean topography by providing total column water vapour data for radar path delay correction. The atmospheric temperature profile is characterized at the oxygen molecule absorption frequencies (60 and 118 GHz) and the humidity profile at the water molecule absorption frequencies (23 and 183 GHz). Total column measurements can be achieved by comparing measured radiometric temperatures at atmospheric window channels, such as 90, 130, and 166 GHz. The standard receiver technology for these frequencies was diode mixers with MMIC LNAs being applied at the lower frequencies. The sensitivity of millimeter wave receivers improved significantly with the introduction of the low noise 35 nm gate length InP MMIC amplifiers. We currently achieve 3 dB noise figure at 180 GHz and 2 dB noise figure at 90 GHz with our MMIC low noise amplifiers (LNAs) in room temperature. These amplifiers and the receivers we have built using them made it possible to conduct highly accurate airborne measurements campaigns from the Global Hawk unmanned aerial vehicle, develop millimeter wave internally calibrated radiometers for altimeter radar path delay correction, and build prototypes of large arrays of millimeter receivers for a geostationary interferometric sounder. We use the developed millimeter wave receivers to measure temperature and humidity profiles in the atmosphere and in hurricanes as well as to characterize the path delay error in ocean topography alitmetery.

  20. Molecular spectroscopy from the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Beckwith, S.

    1985-01-01

    Interstellar and circumstellar molecules are investigated through medium-resolution infrared spectrosocpy of the vibration-rotation and pure rotational transitions. A primary goal was the construction and improvement of instrumentation for the near and middle infrared regions, wavelengths between 2 and 10 microns. The main instrument was a cooled grating spectrometer with an interchangeable detector focal plane which could be used on the Kuiper Airborne Observatory (KAO) for airborne observations, and also at ground-based facilities. Interstellar shock waves were investigated by H2 emission from the Orion Nebula, W51, and the proto-planetary nebulae CRL 2688 and CRL 618. The observations determined the physical conditions in shocked molecular gas near these objects. From these it was possible to characterize the energetic history of mass loss from both pre- and post-main sequence stars in the regions.

  1. Performance metrics for an airborne imaging system

    NASA Astrophysics Data System (ADS)

    Dayton, David C.; Gonglewski, John D.

    2004-11-01

    A series of airborne imaging experiments have been conducted on the island of Maui and at North Oscura Peak in New Mexico. Two platform altitudes were considered 3000 meters and 600 meters, both with a slant range to the target up to 10000 meters. The airborne imaging platform was a Twin Otter aircraft, which circled ground target sites. The second was a fixed platform on a mountain peak overlooking a valley 600 meters below. The experiments were performed during the day using solar illuminated target buildings. Imaging system performance predictions were calculated using standard atmospheric turbulence models, and aircraft boundary layer models. Several different measurement approaches were then used to estimate the actual system performance, and make comparisons with the calculations.

  2. Airborne Infrared Spectroscopy of 1994 Western Wildfires

    NASA Technical Reports Server (NTRS)

    Worden, Helen; Beer, Reinhard; Rinsland, Curtis P.

    1997-01-01

    In the summer of 1994 the 0.07/ cm resolution infrared Airborne Emission Spectrometer (AES) acquired spectral data over two wildfires, one in central Oregon on August 3 and the other near San Luis Obispo, California, on August 15. The spectrometer was on board a NASA DC-8 research aircraft, flying at an altitude of 12 km. The spectra from both fires clearly show features due to water vapor, carbon dioxide, carbon monoxide, ammonia, methanol, formic acid, and ethylene at significantly higher abundance and temperature than observed in downlooking spectra of normal atmospheric and ground conditions. Column densities are derived for several species, and molar ratios are compared with previous biomass fire measurements. We believe that this is the first time such data have been acquired by airborne spectral remote sensing.

  3. Analyzing Options for Airborne Emergency Wireless Communications

    SciTech Connect

    Michael Schmitt; Juan Deaton; Curt Papke; Shane Cherry

    2008-03-01

    In the event of large-scale natural or manmade catastrophic events, access to reliable and enduring commercial communication systems is critical. Hurricane Katrina provided a recent example of the need to ensure communications during a national emergency. To ensure that communication demands are met during these critical times, Idaho National Laboratory (INL) under the guidance of United States Strategic Command has studied infrastructure issues, concerns, and vulnerabilities associated with an airborne wireless communications capability. Such a capability could provide emergency wireless communications until public/commercial nodes can be systematically restored. This report focuses on the airborne cellular restoration concept; analyzing basic infrastructure requirements; identifying related infrastructure issues, concerns, and vulnerabilities and offers recommended solutions.

  4. BOREAS RSS-12 Airborne Tracking Sunphotometer Measurements

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Lobitz, Brad; Spanner, Michael; Wrigley, Robert

    2000-01-01

    The BOREAS RSS-12 team collected both ground and airborne sunphotometer measurements for use in characterizing the aerosol optical properties of the atmosphere during the BOREAS data collection activities. These measurements are to be used to: 1) measure the magnitude and variability of the aerosol optical depth in both time and space; 2) determine the optical properties of the boreal aerosols; and 3) atmospherically correct remotely sensed data acquired during BOREAS. This data set contains airborne tracking sunphotometer data that were acquired from the C-130 aircraft during its flights over the BOREAS study areas. The data cover selected days and times from May to September 1994. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  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. Airborne Microwave Imaging of River Velocities

    NASA Technical Reports Server (NTRS)

    Plant, William J.

    2002-01-01

    The objective of this project was to determine whether airborne microwave remote sensing systems can measure river surface currents with sufficient accuracy to make them prospective instruments with which to monitor river flow from space. The approach was to fly a coherent airborne microwave Doppler radar, developed by APL/UW, on a light airplane along several rivers in western Washington state over an extended period of time. The fundamental quantity obtained by this system to measure river currents is the mean offset of the Doppler spectrum. Since this scatter can be obtained from interferometric synthetic aperture radars (INSARs), which can be flown in space, this project provided a cost effective means for determining the suitability of spaceborne INSAR for measuring river flow.

  7. ARMAR: An airborne rain-mapping radar

    NASA Technical Reports Server (NTRS)

    Durden, S. L.; Im, E.; Li, F. K.; Ricketts, W.; Tanner, A.; Wilson, W.

    1994-01-01

    A new airborne rain-mapping radar (ARMAR) has been developed by NASA and the Jet Propulsion Laboratory for operation on the NASA Ames DC-8 aircraft. The radar operates at 13.8 GHz, the frequency to be used by the radar on the Tropical Rainfall Measuring Mission (TRMM). ARMAR simulates the TRMM radar geometry by looking downward and scanning its antenna in the cross-track direction. This basic compatibility between ARMAR and TRMM allows ARMAR to provide information useful for the TRMM radar design, for rain retrieval algorithm development, and for postlaunch calibration. ARMAR has additional capabilities, including multiple polarization, Doppler velocity measurement, and a radiometer channel for brightness temperature measurement. The system has been tested in both ground-based and airborne configurations. This paper describes the design of the system and shows results of field tests.

  8. Noise sources and noise suppression in CMOS imagers

    NASA Astrophysics Data System (ADS)

    Pain, Bedabrata; Cunningham, Thomas J.; Hancock, Bruce R.

    2004-01-01

    Mechanisms for noise coupling in CMOS imagers are complex, since unlike a CCD, a CMOS imager has to be considered as a full digital-system-on-a-chip, with a highly sensitive front-end. In this paper, we analyze the noise sources in a photodiode CMOS imager, and model their propagation through the signal chain to determine the nature and magnitude of noise coupling. We present methods for reduction of noise, and present measured data to show their viability. For temporal read noise reduction, we present pixel signal chain design techniques to achieve near 2 electrons read noise. We model the front-end reset noise both for conventional photodiode and CTIA type of pixels. For the suppression of reset noise, we present a column feedback-reset method to reduce reset noise below 6 electrons. For spatial noise reduction, we present the design of column signal chain that suppresses both spatial noise and power supply coupling noise. We conclude by identifying problems in low-noise design caused by dark current spatial distribution.

  9. A low-noise current-sensitive amplifier-discriminator system for beta particle counting.

    PubMed

    Sephton, J P; Johansson, L C; Williams, J M

    2008-01-01

    NPL has developed a low-noise current amplifier/discriminator system for radionuclides that emit low-energy electrons and X-rays. The new beta amplifier is based on the low-noise Amptek A-250 operational amplifier. The design has been configured for optimum signal to noise ratio. The new amplifier is described and results obtained using primarily electron-capture decaying radionuclides are presented. The new amplifier gives rise to higher particle detection efficiency than the previously used Atomic Energy of Canada Limited-designed amplifier. This is shown by measurements of (54)Mn and (65)Zn. The counting plateaux are significantly longer and have reduced gradients.

  10. Noise Mitigation During Pile Driving Efficiently Reduces Disturbance of Marine Mammals.

    PubMed

    Nehls, Georg; Rose, Armin; Diederichs, Ansgar; Bellmann, Michael; Pehlke, Hendrik

    2016-01-01

    Acoustic monitoring of harbor porpoises (Phocoena phocoena L., 1758) indicated a strongly reduced disturbance by noise emitted by pile driving for offshore wind turbine foundations insulated by a big bubble curtain (BBC). This newly developed noise mitigation system was tested during construction of the offshore wind farm Borkum West II (North Sea). Because porpoise activity strongly corresponded to the sound level, operation of the new system under its most suitable configuration reduced the porpoise disturbance area by ~90%. Hence, for the first time, a positive effect of a noise mitigation system during offshore pile driving on an affected marine mammal species could be demonstrated.

  11. Noise Mitigation During Pile Driving Efficiently Reduces Disturbance of Marine Mammals.

    PubMed

    Nehls, Georg; Rose, Armin; Diederichs, Ansgar; Bellmann, Michael; Pehlke, Hendrik

    2016-01-01

    Acoustic monitoring of harbor porpoises (Phocoena phocoena L., 1758) indicated a strongly reduced disturbance by noise emitted by pile driving for offshore wind turbine foundations insulated by a big bubble curtain (BBC). This newly developed noise mitigation system was tested during construction of the offshore wind farm Borkum West II (North Sea). Because porpoise activity strongly corresponded to the sound level, operation of the new system under its most suitable configuration reduced the porpoise disturbance area by ~90%. Hence, for the first time, a positive effect of a noise mitigation system during offshore pile driving on an affected marine mammal species could be demonstrated. PMID:26611029

  12. Highly efficient white top-emitting organic light-emitting diodes comprising laminated microlens films.

    PubMed

    Thomschke, Michael; Reineke, Sebastian; Lüssem, Björn; Leo, Karl

    2012-01-11

    White top-emitting organic light-emitting diodes (OLEDs) attract much attention, as they are optically independent from the substrate used. While monochrome top-emitting OLEDs can be designed easily to have high-emission efficiency, white light emission faces obstacles. The commonly used thin metal layers as top electrodes turn the device into a microresonator having detrimental narrow and angular dependent emission characteristics. Here we report on a novel concept to improve the color quality and efficiency of white top-emitting OLEDs. We laminate a refractive index-matched microlens film on the top-emitting device. The microlens film acts both as outcoupling-enhancing film and an integrating element, mixing the optical modes to a broadband spectrum. PMID:22132876

  13. Highly efficient white top-emitting organic light-emitting diodes comprising laminated microlens films.

    PubMed

    Thomschke, Michael; Reineke, Sebastian; Lüssem, Björn; Leo, Karl

    2012-01-11

    White top-emitting organic light-emitting diodes (OLEDs) attract much attention, as they are optically independent from the substrate used. While monochrome top-emitting OLEDs can be designed easily to have high-emission efficiency, white light emission faces obstacles. The commonly used thin metal layers as top electrodes turn the device into a microresonator having detrimental narrow and angular dependent emission characteristics. Here we report on a novel concept to improve the color quality and efficiency of white top-emitting OLEDs. We laminate a refractive index-matched microlens film on the top-emitting device. The microlens film acts both as outcoupling-enhancing film and an integrating element, mixing the optical modes to a broadband spectrum.

  14. Investigation of the influence of magnetostriction and magnetic forces on transformer core noise and vibration

    NASA Astrophysics Data System (ADS)

    Phophongviwat, Teeraphon

    Transformer noise is of increasing environmental concern so continued efforts are being made by electrical steel and transformer producers to satisfy users by reducing the noise. Magnetostriction and magnetic forces are the main causes of transformer core noise and vibration. Understanding of the relationship from the core material to core structure and core vibration to core noise can help the design of low noise transformer cores. The most appropriate parameter for investigating the relationship between noise and vibration is sound pressure (in the unit of Pascals) in the frequency domain because it is not A-weighted. In this study, the side surfaces of transformer cores were found to emit higher noise than front and top surfaces at low magnetic induction. When the magnetic induction was increased, the effect of magnetic force increased and caused the front surfaces to emit higher noise. For three phase three limb transformer cores, the front surface of the middle limb generated higher noise than the outer limbs due to the effect of T-joint. However this does not translate higher noise level because of the phase difference of the vibration between the limbs. Due to this A-weighted sound power level of three phase, three limb transformer cores were shown to be lower than single phase transformer cores, although at the same cross sectional area and core window size the three phase cores has larger size.. A model, developed to separate the effects of magnetostriction and magnetic forces on transformer core vibration, showed that at low induction, magnetostriction is more significant than magnetic forces. The magnetic forces become more significant than magnetostriction when the induction is increased. Magnetostriction primarily depends on material and stress but magnetic forces principally depend on core building. Louder noise can be generated from a core built with low magnetostriction material than higher magnetostriction if the building tolerances are worse. The

  15. Visible light surface emitting semiconductor laser

    DOEpatents

    Olbright, Gregory R.; Jewell, Jack L.

    1993-01-01

    A vertical-cavity surface-emitting laser is disclosed comprising a laser cavity sandwiched between two distributed Bragg reflectors. The laser cavity comprises a pair of spacer layers surrounding one or more active, optically emitting quantum-well layers having a bandgap in the visible which serve as the active optically emitting material of the device. The thickness of the laser cavity is m .lambda./2n.sub.eff where m is an integer, .lambda. is the free-space wavelength of the laser radiation and n.sub.eff is the effective index of refraction of the cavity. Electrical pumping of the laser is achieved by heavily doping the bottom mirror and substrate to one conductivity-type and heavily doping regions of the upper mirror with the opposite conductivity type to form a diode structure and applying a suitable voltage to the diode structure. Specific embodiments of the invention for generating red, green, and blue radiation are described.

  16. Airborne Chemical Sensing with Mobile Robots

    PubMed Central

    Lilienthal, Achim J.; Loutfi, Amy; Duckett, Tom

    2006-01-01

    Airborne chemical sensing with mobile robots has been an active research area since the beginning of the 1990s. This article presents a review of research work in this field, including gas distribution mapping, trail guidance, and the different subtasks of gas source localisation. Due to the difficulty of modelling gas distribution in a real world environment with currently available simulation techniques, we focus largely on experimental work and do not consider publications that are purely based on simulations.

  17. NASA's Airborne Astronomy Program - Lessons For SOFIA

    NASA Astrophysics Data System (ADS)

    Erickson, Edwin F.

    2007-07-01

    Airborne astronomy was pioneered and has evolved at NASA Ames Research Center near San Francisco, California, since 1965. Nowhere else in the world has a similar program been implemented. Its many unique features deserve description, especially for the benefit of planning the operation of SOFIA, the Stratospheric Observatory for Infrared Astronomy, and in particular since NASA Headquarters’ recent decision to base SOFIA operations at Dryden Flight Research Center at Edwards, California instead of at Ames. The history of Ames’ airborne astronomy program is briefly summarized. Discussed in more detail are the operations and organization of the 21-year Kuiper Airborne Observatory (KAO) program, which provide important lessons for SOFIA. The KAO program is our best prototype for planning effective SOFIA operations. Principal features of the KAO program which should be retained on SOFIA are: unique science, innovative new science instruments and technologies, training of young scientists, an effective education and public outreach program, flexibility, continuous improvement, and efficient operations with a lean, well integrated team. KAO program features which should be improved upon with SOFIA are: (1) a management structure that is dedicated primarily to safely maximizing scientific productivity for the resources available, headed by a scientist who is the observatory director, and (2) stimuli to assure prompt distribution and accessibility of data to the scientific community. These and other recommendations were recorded by the SOFIA Science Working Group in 1995, when the KAO was decommissioned to start work on SOFIA. Further operational and organizational factors contributing to the success of the KAO program are described. Their incorporation into SOFIA operations will help assure the success of this new airborne observatory. SOFIA is supported by NASA in the U.S. and DLR (the German Aerospace Center) in Germany.

  18. Flight results for the airborne Raman lidar

    NASA Technical Reports Server (NTRS)

    Heaps, William S.; Burris, John F.

    1995-01-01

    The airborne Raman lidar recently completed a series of flight tests aboard a C-130 aircraft operated by the NASA Wallops Flight Facility. The Raman lidar is intended to make simultaneous remote measurements of methane, water vapor, temperature, and pressure. The principal purpose of the measurements is to aid in the investigation of polar phenomena related to the formation of ozone 'holes' by permitting the identification of the origin of air parcels using methane as a tracer.

  19. Airborne electronics for automated flight systems

    NASA Technical Reports Server (NTRS)

    Graves, G. B., Jr.

    1975-01-01

    The increasing importance of airborne electronics for use in automated flight systems is briefly reviewed with attention to both basic aircraft control functions and flight management systems for operational use. The requirements for high levels of systems reliability are recognized. Design techniques are discussed and the areas of control systems, computing and communications are considered in terms of key technical problems and trends for their solution.

  20. Holographic Airborne Rotating Lidar Instrument Experiment (HARLIE)

    NASA Technical Reports Server (NTRS)

    Schwemmer, Geary K.

    1998-01-01

    Scanning holographic lidar receivers are currently in use in two operational lidar systems, PHASERS (Prototype Holographic Atmospheric Scanner for Environmental Remote Sensing) and now HARLIE (Holographic Airborne Rotating Lidar Instrument Experiment). These systems are based on volume phase holograms made in dichromated gelatin (DCG) sandwiched between 2 layers of high quality float glass. They have demonstrated the practical application of this technology to compact scanning lidar systems at 532 and 1064 nm wavelengths, the ability to withstand moderately high laser power and energy loading, sufficient optical quality for most direct detection systems, overall efficiencies rivaling conventional receivers, and the stability to last several years under typical lidar system environments. Their size and weight are approximately half of similar performing scanning systems using reflective optics. The cost of holographic systems will eventually be lower than the reflective optical systems depending on their degree of commercialization. There are a number of applications that require or can greatly benefit from a scanning capability. Several of these are airborne systems, which either use focal plane scanning, as in the Laser Vegetation Imaging System or use primary aperture scanning, as in the Airborne Oceanographic Lidar or the Large Aperture Scanning Airborne Lidar. The latter class requires a large clear aperture opening or window in the aircraft. This type of system can greatly benefit from the use of scanning transmission holograms of the HARLIE type because the clear aperture required is only about 25% larger than the collecting aperture as opposed to 200-300% larger for scan angles of 45 degrees off nadir.

  1. Exploring Noise: Sound Pollution.

    ERIC Educational Resources Information Center

    Rillo, Thomas J.

    1979-01-01

    Part one of a three-part series about noise pollution and its effects on humans. This section presents the background information for teachers who are preparing a unit on sound. The next issues will offer learning activities for measuring the effects of sound and some references. (SA)

  2. Noise Control through Education.

    ERIC Educational Resources Information Center

    Pennino, Martha

    1979-01-01

    Discussed are the public education and information programs on noise pollution control currently in operation within the Metropolitan Washington, D.C. area that have been either developed or implemented under the auspices of the Metropolitan Washington Council of Governments. (BT)

  3. Curing the noise epidemic

    NASA Astrophysics Data System (ADS)

    Mazer, Susan

    2005-09-01

    The argument is made that design does not stop when the fixed architectural and acoustical components are in place. Spaces live and breathe with the people who reside in them. Research and examples are presented that show that noise, auditory clutter, thrives on itself in hospitals. Application of the Lombard reflex studies fit into the hospital setting, but do not offer solutions as to how one might reduce the impact. In addition, the basis for looking at the noise component as a physical as well cultural dynamic will be addressed. Whether the result of the wrong conversation in the wrong place or the right conversation in an unfortunate place, talk mixed with sounds of technology is shown to cause its own symptoms. From heightened anxiety and stress to medical errors, staff burnout, or HIPAA violations, the case is made that noise is pandemic in hospitals and demands financial and operational investment. An explanation of how to reduce noise by design of the dynamic environment - equipment, technology, staff protocols is also provided.

  4. Noise: A Health Problem.

    ERIC Educational Resources Information Center

    Environmental Protection Agency, Washington, DC. Office of Noise Abatement and Control.

    This booklet contains nine sections describing ways in which noise may endanger health and well-being. Secions are included on: (1) hearing loss; (2) heart disease; (3) other reactions by the body; (4) effects on the unborn; (5) special effects on children; (6) intrusion at home and work; (7) sleep disruption; (8) mental and social well-being; and…

  5. Noise Assessment Guidelines.

    ERIC Educational Resources Information Center

    Schultz, Theodore J.; McMahon, Nancy M.

    The Department of Housing and Urban Development (HUD), in its efforts to provide decent housing and a suitable living environment, is concerned with noise as a major source of environmental pollution. To this end, these guidelines are presented to provide site screening techniques. The procedures described have been developed so that people…

  6. Light Emitting Diodes and Astronomical Environments: Results from in situ Field Measurements

    NASA Astrophysics Data System (ADS)

    Craine, Brian L.; Craine, Eric R.

    2015-05-01

    Light emitting diode (LED) light fixtures are rapidly becoming industry standards for outdoor lighting. They are promoted on the strength of long lifetimes (hence economic efficiencies), low power requirements, directability, active brightness controls, and energy efficiency. They also tend to produce spectral shifts that are undesirable in astronomical settings, but which can be moderated by filters. LED lighting for continuous roadway and parking lot lighting is particularly popular, and many communities are in the process of retrofitting Low Pressure Sodium (LPS) and other lights by tens of thousands of new LED fixtures at a time. What is the impact of this process on astronomical observatories and on dark skies upon which amateur astronomers rely? We bypass modeling and predictions to make actual measurements of these lights in the field. We report on original ground, airborne, and satellite observations of LED lights and discuss their light budgets, zenith angle functions, and impacts on observatory environs.

  7. Playback Experiments for Noise Exposure.

    PubMed

    Holles, Sophie; Simpson, Stephen D; Lecchini, David; Radford, Andrew N

    2016-01-01

    Playbacks are a useful tool for conducting well-controlled and replicated experiments on the effects of anthropogenic noise, particularly for repeated exposures. However, playbacks are unlikely to fully reproduce original sources of anthropogenic noise. Here we examined the sound pressure and particle acceleration of boat noise playbacks in a field experiment and reveal that although there remain recognized limitations, the signal-to-noise ratios of boat playbacks to ambient noise do not exceed those of a real boat. The experimental setup tested is therefore of value for use in experiments on the effects of repeated exposure of aquatic animals to boat noise. PMID:26610992

  8. Airborne Infrared Spectrograph for Eclipse Observations

    NASA Astrophysics Data System (ADS)

    Golub, L.; Cheimets, P.; DeLuca, E. E.; Samra, J.; Judge, P. G.

    2015-12-01

    Direct measurements of the coronal magnetic field have significant potential to enhance our understanding of coronal dynamics, and improve forecasting models. Of particular interest are observations of coronal field lines in the Transition Corona, the transitional region between closed and open flux systems, providing important information on eruptive instabilities and on the origin of the slow solar wind. While current instruments routinely observe the photospheric and chromospheric magnetic fields, the proposed airborne spectrometer will take a step toward the direct observation of coronal fields by measuring plasma emission in the infrared at high spatial and spectral resolution. The targeted lines are five forbidden magnetic dipole transitions between 1.4 and 4 um. The airborne system will consist of a telescope, grating spectrometer and pointing/stabilization system to be flown on the NSF/NCAR High-performance Instrumented Airborne Platform for Environmental Research (HIAPER) during the 21 August 2017 total solar eclipse. We will discuss the scientific objectives of the 2017 flight, describe details of the instrument design, and present the observing program for the eclipse.

  9. Optical Communications Link to Airborne Transceiver

    NASA Technical Reports Server (NTRS)

    Regehr, Martin W.; Kovalik, Joseph M.; Biswas, Abhijit

    2011-01-01

    An optical link from Earth to an aircraft demonstrates the ability to establish a link from a ground platform to a transceiver moving overhead. An airplane has a challenging disturbance environment including airframe vibrations and occasional abrupt changes in attitude during flight. These disturbances make it difficult to maintain pointing lock in an optical transceiver in an airplane. Acquisition can also be challenging. In the case of the aircraft link, the ground station initially has no precise knowledge of the aircraft s location. An airborne pointing system has been designed, built, and demonstrated using direct-drive brushless DC motors for passive isolation of pointing disturbances and for high-bandwidth control feedback. The airborne transceiver uses a GPS-INS system to determine the aircraft s position and attitude, and to then illuminate the ground station initially for acquisition. The ground transceiver participates in link-pointing acquisition by first using a wide-field camera to detect initial illumination from the airborne beacon, and to perform coarse pointing. It then transfers control to a high-precision pointing detector. Using this scheme, live video was successfully streamed from the ground to the aircraft at 270 Mb/s while simultaneously downlinking a 50 kb/s data stream from the aircraft to the ground.

  10. Airborne myxomycete spores: detection using molecular techniques

    NASA Astrophysics Data System (ADS)

    Kamono, Akiko; Kojima, Hisaya; Matsumoto, Jun; Kawamura, Kimitaka; Fukui, Manabu

    2009-01-01

    Myxomycetes are organisms characterized by a life cycle that includes a fruiting body stage. Myxomycete fruiting bodies contain spores, and wind dispersal of the spores is considered important for this organism to colonize new areas. In this study, the presence of airborne myxomycetes and the temporal changes in the myxomycete composition of atmospheric particles (aerosols) were investigated with a polymerase chain reaction (PCR)-based method for Didymiaceae and Physaraceae. Twenty-one aerosol samples were collected on the roof of a three-story building located in Sapporo, Hokkaido Island, northern Japan. PCR analysis of DNA extracts from the aerosol samples indicated the presence of airborne myxomycetes in all the samples, except for the one collected during the snowfall season. Denaturing gradient gel electrophoresis (DGGE) analysis of the PCR products showed seasonally varying banding patterns. The detected DGGE bands were subjected to sequence analyses, and four out of nine obtained sequences were identical to those of fruiting body samples collected in Hokkaido Island. It appears that the difference in the fruiting period of each species was correlated with the seasonal changes in the myxomycete composition of the aerosols. Molecular evidence shows that newly formed spores are released and dispersed in the air, suggesting that wind-driven dispersal of spores is an important process in the life history of myxomycetes. This study is the first to detect airborne myxomycetes with the use of molecular ecological analyses and to characterize their seasonal distribution.

  11. Airborne Tactical Free-Electron Laser

    SciTech Connect

    Whitney, Roy; Neil, George

    2007-02-01

    The goal of 100 kilowatts (kW) of directed energy from an airborne tactical platform has proved challenging due to the size and weight of most of the options that have been considered. However, recent advances in Free-Electron Lasers appear to offer a solution along with significant tactical advantages: a nearly unlimited magazine, time structures for periods from milliseconds to hours, radar like functionality, and the choice of the wavelength of light that best meets mission requirements. For an Airborne Tactical Free-Electron Laser (ATFEL) on a platforms such as a Lockheed C-130J-30 and airships, the two most challenging requirements, weight and size, can be met by generating the light at a higher harmonic, aggressively managing magnet weights, managing cryogenic heat loads using recent SRF R&D results, and using FEL super compact design concepts that greatly reduce the number of components. The initial R&D roadmap for achieving an ATFEL is provided in this paper. Performing this R&D is expected to further reduce the weight, size and power requirements for the FELs the Navy is currently developing for shipboard applications, as well as providing performance enhancements for the strategic airborne MW class FELs. The 100 kW ATFEL with its tactical advantages may prove sufficiently attractive for early advancement in the queue of deployed FELs.

  12. Airborne multispectral detection of regrowth cotton fields

    NASA Astrophysics Data System (ADS)

    Westbrook, John K.; Suh, Charles P.-C.; Yang, Chenghai; Lan, Yubin; Eyster, Ritchie S.

    2015-01-01

    Effective methods are needed for timely areawide detection of regrowth cotton plants because boll weevils (a quarantine pest) can feed and reproduce on these plants beyond the cotton production season. Airborne multispectral images of regrowth cotton plots were acquired on several dates after three shredding (i.e., stalk destruction) dates. Linear spectral unmixing (LSU) classification was applied to high-resolution airborne multispectral images of regrowth cotton plots to estimate the minimum detectable size and subsequent growth of plants. We found that regrowth cotton fields can be identified when the mean plant width is ˜0.2 m for an image resolution of 0.1 m. LSU estimates of canopy cover of regrowth cotton plots correlated well (r2=0.81) with the ratio of mean plant width to row spacing, a surrogate measure of plant canopy cover. The height and width of regrowth plants were both well correlated (r2=0.94) with accumulated degree-days after shredding. The results will help boll weevil eradication program managers use airborne multispectral images to detect and monitor the regrowth of cotton plants after stalk destruction, and identify fields that may require further inspection and mitigation of boll weevil infestations.

  13. Improved Airborne System for Sensing Wildfires

    NASA Technical Reports Server (NTRS)

    McKeown, Donald; Richardson, Michael

    2008-01-01

    The Wildfire Airborne Sensing Program (WASP) is engaged in a continuing effort to develop an improved airborne instrumentation system for sensing wildfires. The system could also be used for other aerial-imaging applications, including mapping and military surveillance. Unlike prior airborne fire-detection instrumentation systems, the WASP system would not be based on custom-made multispectral line scanners and associated custom- made complex optomechanical servomechanisms, sensors, readout circuitry, and packaging. Instead, the WASP system would be based on commercial off-the-shelf (COTS) equipment that would include (1) three or four electronic cameras (one for each of three or four wavelength bands) instead of a multispectral line scanner; (2) all associated drive and readout electronics; (3) a camera-pointing gimbal; (4) an inertial measurement unit (IMU) and a Global Positioning System (GPS) receiver for measuring the position, velocity, and orientation of the aircraft; and (5) a data-acquisition subsystem. It would be necessary to custom-develop an integrated sensor optical-bench assembly, a sensor-management subsystem, and software. The use of mostly COTS equipment is intended to reduce development time and cost, relative to those of prior systems.

  14. Methods for Sampling of Airborne Viruses

    PubMed Central

    Verreault, Daniel; Moineau, Sylvain; Duchaine, Caroline

    2008-01-01

    Summary: To better understand the underlying mechanisms of aerovirology, accurate sampling of airborne viruses is fundamental. The sampling instruments commonly used in aerobiology have also been used to recover viruses suspended in the air. We reviewed over 100 papers to evaluate the methods currently used for viral aerosol sampling. Differentiating infections caused by direct contact from those caused by airborne dissemination can be a very demanding task given the wide variety of sources of viral aerosols. While epidemiological data can help to determine the source of the contamination, direct data obtained from air samples can provide very useful information for risk assessment purposes. Many types of samplers have been used over the years, including liquid impingers, solid impactors, filters, electrostatic precipitators, and many others. The efficiencies of these samplers depend on a variety of environmental and methodological factors that can affect the integrity of the virus structure. The aerodynamic size distribution of the aerosol also has a direct effect on sampler efficiency. Viral aerosols can be studied under controlled laboratory conditions, using biological or nonbiological tracers and surrogate viruses, which are also discussed in this review. Lastly, general recommendations are made regarding future studies on the sampling of airborne viruses. PMID:18772283

  15. MITAS: multisensor imaging technology for airborne surveillance

    NASA Astrophysics Data System (ADS)

    Thomas, John D.

    1991-08-01

    MITAS, a unique and low-cost solution to the problem of collecting and processing multisensor imaging data for airborne surveillance operations has been developed, MITAS results from integrating the established and proven real-time video processing, target tracking, and sensor management software of TAU with commercially available image exploitation and map processing software. The MITAS image analysis station (IAS) supports airborne day/night reconnaissance and surveillance missions involving low-altitude collection platforms employing a suite of sensors to perform reconnaissance functions against a variety of ground and sea targets. The system will detect, locate, and recognize threats likely to be encountered in support of counternarcotic operations and in low-intensity conflict areas. The IAS is capable of autonomous, near real-time target exploitation and has the appropriate communication links to remotely located IAS systems for more extended analysis of sensor data. The IAS supports the collection, fusion, and processing of three main imaging sensors: daylight imagery (DIS), forward looking infrared (FLIR), and infrared line scan (IRLS). The MITAS IAS provides support to all aspects of the airborne surveillance mission, including sensor control, real-time image enhancement, automatic target tracking, sensor fusion, freeze-frame capture, image exploitation, target data-base management, map processing, remote image transmission, and report generation.

  16. Cryospheric Applications of Modern Airborne Photogrammetry

    NASA Astrophysics Data System (ADS)

    Nolan, M.

    2014-12-01

    Airborne photogrammetry is undergoing a renaissance. Lower-cost equipment, more powerful software, and simplified methods have lowered the barriers-to-entry significantly and now allow repeat-mapping of cryospheric dynamics that were previously too expensive to consider. The current state-of-the-art is the ability to use an airborne equipment package costing less than $20,000 to make topographic maps on landscape-scales at 10 cm pixel size with a vertical repeatability of about 10 cm. Nearly any surface change on the order of decimeters can be measured using these techniques through analysis of time-series of such maps. This presentation will discuss these new methods and their application to cryospheric dynamics such as the measurement of snow depth, coastal erosion, valley-glacier volume-change, permafrost thaw, frost heave of infrastructure, river bed geomorphology, and aufeis melt. Because of the expense of other airborne methods, by necessity measurements of these dynamics are currently most often made on the ground along benchmark transects that are then extrapolated to the broader scale. The ability to directly measure entire landscapes with equal or higher accuracy than transects eliminates the need to extrapolate them and the ability to do so at lower costs than transects may revolutionize the way we approach studying change in the cryosphere, as well as our understanding of the cryosphere itself.

  17. Emissions of airborne toxics from coal-fired boilers: Mercury

    SciTech Connect

    Huang, H.S.; Livengood, C.D.; Zaromb, S.

    1991-09-01

    Concerns over emissions of hazardous air Pollutants (air toxics) have emerged as a major environmental issue, and the authority of the US Environmental Protection Agency to regulate such pollutants was greatly expanded through the Clean Air Act Amendments of 1990. Mercury has been singled out for particular attention because of concerns over possible effects of emissions on human health. This report evaluates available published information on the mercury content of coals mined in the United States, on mercury emitted in coal combustion, and on the efficacy of various environmental control technologies for controlling airborne emissions. Anthracite and bituminous coals have the highest mean-mercury concentrations, with subbituminous coals having the lowest. However, all coal types show very significant variations in mercury concentrations. Mercury emissions from coal combustion are not well-characterized, particularly with regard to determination of specific mercury compounds. Variations in emission rates of more than an order of magnitude have been reported for some boiler types. Data on the capture of mercury by environmental control technologies are available primarily for systems with electrostatic precipitators, where removals of approximately 20% to over 50% have been reported. Reported removals for wet flue-gas-desulfurization systems range between 35 and 95%, while spray-dryer/fabric-filter systems have given removals of 75 to 99% on municipal incinerators. In all cases, better data are needed before any definitive judgments can be made. This report briefly reviews several areas of research that may lead to improvements in mercury control for existing flue-gas-clean-up technologies and summarizes the status of techniques for measuring mercury emissions from combustion sources.

  18. Fighting noise with noise in realistic quantum teleportation

    NASA Astrophysics Data System (ADS)

    Fortes, Raphael; Rigolin, Gustavo

    2015-07-01

    We investigate how the efficiency of the quantum teleportation protocol is affected when the qubits involved in the protocol are subjected to noise or decoherence. We study all types of noise usually encountered in real-world implementations of quantum communication protocols, namely, the bit-flip, phase-flip (phase damping), depolarizing, and amplitude-damping noise. Several realistic scenarios are studied in which a part or all of the qubits employed in the execution of the quantum teleportation protocol are subjected to the same or different types of noise. We find noise scenarios not yet known in which more noise or less entanglement lead to more efficiency. Furthermore, we show that if noise is unavoidable it is better to subject the qubits to different noise channels in order to obtain an increase in the efficiency of the protocol.

  19. Reduction of turbomachinery noise

    NASA Technical Reports Server (NTRS)

    Waitz, Ian A. (Inventor); Brookfield, John M. (Inventor); Sell, Julian (Inventor); Hayden, Belva J. (Inventor); Ingard, K. Uno (Inventor)

    1999-01-01

    In the invention, propagating broad band and tonal acoustic components of noise characteristic of interaction of a turbomachine blade wake, produced by a turbomachine blade as the blade rotates, with a turbomachine component downstream of the rotating blade, are reduced. This is accomplished by injection of fluid into the blade wake through a port in the rotor blade. The mass flow rate of the fluid injected into the blade wake is selected to reduce the momentum deficit of the wake to correspondingly increase the time-mean velocity of the wake and decrease the turbulent velocity fluctuations of the wake. With this fluid injection, reduction of both propagating broad band and tonal acoustic components of noise produced by interaction of the blade wake with a turbomachine component downstream of the rotating blade is achieved. In a further noise reduction technique, boundary layer fluid is suctioned into the turbomachine blade through a suction port on the side of the blade that is characterized as the relatively low-pressure blade side. As with the fluid injection technique, the mass flow rate of the fluid suctioned into the blade is here selected to reduce the momentum deficit of the wake to correspondingly increase the time-mean velocity of the wake and decrease the turbulent velocity fluctuations of the wake; reduction of both propagating broad band and tonal acoustic components of noise produced by interaction of the blade wake with a turbomachine component downstream of the rotating blade is achieved with this suction technique. Blowing and suction techniques are also provided in the invention for reducing noise associated with the wake produced by fluid flow around a stationary blade upstream of a rotating turbomachine.

  20. Tandem Cylinder Noise Predictions

    NASA Technical Reports Server (NTRS)

    Lockhard, David P.; Khorrami, Mehdi R.; CHoudhari, Meelan M.; Hutcheson, Florence V.; Brooks, Thomas F.; Stead, Daniel J.

    2007-01-01

    In an effort to better understand landing-gear noise sources, we have been examining a simplified configuration that still maintains some of the salient features of landing-gear flow fields. In particular, tandem cylinders have been studied because they model a variety of component level interactions. The present effort is directed at the case of two identical cylinders spatially separated in the streamwise direction by 3.7 diameters. Experimental measurements from the Basic Aerodynamic Research Tunnel (BART) and Quiet Flow Facility (QFF) at NASA Langley Research Center (LaRC) have provided steady surface pressures, detailed off-surface measurements of the flow field using Particle Image Velocimetry (PIV), hot-wire measurements in the wake of the rear cylinder, unsteady surface pressure data, and the radiated noise. The experiments were conducted at a Reynolds number of 166 105 based on the cylinder diameter. A trip was used on the upstream cylinder to insure a fully turbulent shedding process and simulate the effects of a high Reynolds number flow. The parallel computational effort uses the three-dimensional Navier-Stokes solver CFL3D with a hybrid, zonal turbulence model that turns off the turbulence production term everywhere except in a narrow ring surrounding solid surfaces. The current calculations further explore the influence of the grid resolution and spanwise extent on the flow and associated radiated noise. Extensive comparisons with the experimental data are used to assess the ability of the computations to simulate the details of the flow. The results show that the pressure fluctuations on the upstream cylinder, caused by vortex shedding, are smaller than those generated on the downstream cylinder by wake interaction. Consequently, the downstream cylinder dominates the noise radiation, producing an overall directivity pattern that is similar to that of an isolated cylinder. Only calculations based on the full length of the model span were able to

  1. Channel-noise-induced stochastic facilitation in an auditory brainstem neuron model

    NASA Astrophysics Data System (ADS)

    Schmerl, Brett A.; McDonnell, Mark D.

    2013-11-01

    Neuronal membrane potentials fluctuate stochastically due to conductance changes caused by random transitions between the open and closed states of ion channels. Although it has previously been shown that channel noise can nontrivially affect neuronal dynamics, it is unknown whether ion-channel noise is strong enough to act as a noise source for hypothesized noise-enhanced information processing in real neuronal systems, i.e., “stochastic facilitation”. Here we demonstrate that biophysical models of channel noise can give rise to two kinds of recently discovered stochastic facilitation effects in a Hodgkin-Huxley-like model of auditory brainstem neurons. The first, known as slope-based stochastic resonance (SBSR), enables phasic neurons to emit action potentials that can encode the slope of inputs that vary slowly relative to key time constants in the model. The second, known as inverse stochastic resonance (ISR), occurs in tonically firing neurons when small levels of noise inhibit tonic firing and replace it with burstlike dynamics. Consistent with previous work, we conclude that channel noise can provide significant variability in firing dynamics, even for large numbers of channels. Moreover, our results show that possible associated computational benefits may occur due to channel noise in neurons of the auditory brainstem. This holds whether the firing dynamics in the model are phasic (SBSR can occur due to channel noise) or tonic (ISR can occur due to channel noise).

  2. Quantitative method for measuring heat flux emitted from a cryogenic object

    DOEpatents

    Duncan, R.V.

    1993-03-16

    The present invention is a quantitative method for measuring the total heat flux, and of deriving the total power dissipation, of a heat-fluxing object which includes the steps of placing an electrical noise-emitting heat-fluxing object in a liquid helium bath and measuring the superfluid transition temperature of the bath. The temperature of the liquid helium bath is thereafter reduced until some measurable parameter, such as the electrical noise, exhibited by the heat-fluxing object or a temperature-dependent resistive thin film in intimate contact with the heat-fluxing object, becomes greatly reduced. The temperature of the liquid helum bath is measured at this point. The difference between the superfluid transition temperature of the liquid helium bath surrounding the heat-fluxing object, and the temperature of the liquid helium bath when the electrical noise emitted by the heat-fluxing object becomes greatly reduced, is determined. The total heat flux from the heat-fluxing object is determined as a function of this difference between these temperatures. In certain applications, the technique can be used to optimize thermal design parameters of cryogenic electronics, for example, Josephson junction and infrared sensing devices.

  3. Quantitative method for measuring heat flux emitted from a cryogenic object

    DOEpatents

    Duncan, Robert V.

    1993-01-01

    The present invention is a quantitative method for measuring the total heat flux, and of deriving the total power dissipation, of a heat-fluxing object which includes the steps of placing an electrical noise-emitting heat-fluxing object in a liquid helium bath and measuring the superfluid transition temperature of the bath. The temperature of the liquid helium bath is thereafter reduced until some measurable parameter, such as the electrical noise, exhibited by the heat-fluxing object or a temperature-dependent resistive thin film in intimate contact with the heat-fluxing object, becomes greatly reduced. The temperature of the liquid helum bath is measured at this point. The difference between the superfluid transition temperature of the liquid helium bath surrounding the heat-fluxing object, and the temperature of the liquid helium bath when the electrical noise emitted by the heat-fluxing object becomes greatly reduced, is determined. The total heat flux from the heat-fluxing object is determined as a function of this difference between these temperatures. In certain applications, the technique can be used to optimize thermal design parameters of cryogenic electronics, for example, Josephson junction and infra-red sensing devices.

  4. A new airborne Ka-band double-antenna microwave radiometer for cloud liquid water content measurement

    NASA Astrophysics Data System (ADS)

    Sun, Jian; Zhao, Kai; Jiang, Tao; Gu, Lingjia

    2013-09-01

    A new type upward-looking airborne double-antenna microwave radiometer (ADAMR) system intended for detecting atmospheric cloud liquid water content (LWC) is developed in this paper. The frequency of this radiometer is 31.65 GHz. For the antenna elevation angle, one is 30°and the other is 90°. In order to detect the signals with low effective noise temperature (<10K) from the LWC, the noise coupling technique is used. Through injecting constant equal noise signal into the two antenna ports respectively, the technique can elevate the small input noise signal power to the detectable range of the square-law detector and thus realize the weak signal detection. Moreover, in order to eliminate the impacts of the system gain fluctuations and obtain a higher sensitivity, an auto-gain compensation method based on the analog-to-digital converter, microcontroller and host computer software techniques is also proposed. Compared with the traditional radiometers, the radiometer topology is greatly simplified and the gain fluctuations can be readily realtime compensated using the compensation method. The laboratory test results show that radiometric sensitivity is better than 0.2 K for 300ms integration time and the instrument is conforming to specifications. Finally, the flight observation experiment results are presented to prove that the designed instrument is able to detect small changes of noise signal in a wide effective range of noise temperature (10-350K) and is a powerful tool for LWC measurement.

  5. Evaluation of seismic noise for landmine detection system development

    NASA Astrophysics Data System (ADS)

    Martin, James S.; Larson, Gregg D.; Scott, Waymond R., Jr.; McCall, George S., II

    2003-09-01

    For several years a system has been under development at Georgia Tech that uses seismic surface waves to detect and image buried landmines. The details of this system have been previously reported in the literature. Current work involves the transition from a laboratory experimental system to a field-operable experimental system with the ultimate goal of creating an integrated field-operable prototype. Several issues have arisen in the transition to field testing. One of these is the nature and magnitude of the noise levels that limit system performance at field sites and the relevance of these for predicting noise that might be encountered in a realistic demining scenario. Noise introduced to the system sensor (a radar-based, non-contact displacement sensor) can arise from many sources (both natural and manmade). It may be received through a variety of mechanisms in addition to the sensor's primary transduction mechanism. Moreover, even noise which is received through the primary transduction mechanism need not involve purely seismic motion of the ground that is being interrogated. It might instead represent motion of the sensor's support structure or the purely local coupling of airborne noise into surface motion. To understand these effects, measurements have been made using ground contacting sensors at four field sites where other system-related measurements have also been made. The nature of the noise measurements has required that refinements be made to both the sensors themselves (triaxial geophones) and to the data acquisition system used for the measurement of the system"s seismic interrogation signals (a 12-bit, PC-based digitizer).

  6. A portable battery-powered continuous airborne {sup 222}Rn sampler

    SciTech Connect

    Scarpitta, S.; Kadnar, M.

    1998-04-01

    The Polyport, designed at the Environmental Measurements Laboratory (EML) for deployment in atmospheric balloons or remote areas, was laboratory and field tested to determine its effectiveness in collecting {sup 222}Rn gas in dry and humid air. Twelve 6-cm long tubes containing 0.4 g of Carboxen{trademark}-564 a hydrophobic beaded carbon molecular sieve (BCMS) material efficiently adsorbs airborne {sup 222}Rn under dynamic sampling conditions of 1--2 hr duration. The exposed sorbent is later weighed for water uptake, transferred and counted in a low background liquid scintillation (LS) counter that can detect alpha and beta emitting {sup 222}Rn progeny with a maximum counting efficiency of 5 cpm per dpm. Each sorbent tube can be gamma counted if it contains sufficient adsorbed {sup 214}Pb and {sup 214}Bi activity. The variables tested were sampling flow rate, temperature, sampling time and relative humidity (RH).

  7. MAPIR: An Airborne Polarmetric Imaging Radiometer in Support of Hydrologic Satellite Observations

    NASA Technical Reports Server (NTRS)

    Laymon, C.; Al-Hamdan, M.; Crosson, W.; Limaye, A.; McCracken, J.; Meyer, P.; Richeson, J.; Sims, W.; Srinivasan, K.; Varnevas, K.

    2010-01-01

    In this age of dwindling water resources and increasing demands, accurate estimation of water balance components at every scale is more critical to end users than ever before. Several near-term Earth science satellite missions are aimed at global hydrologic observations. The Marshall Airborne Polarimetric Imaging Radiometer (MAPIR) is a dual beam, dual angle polarimetric, scanning L band passive microwave radiometer system developed by the Observing Microwave Emissions for Geophysical Applications (OMEGA) team at MSFC to support algorithm development and validation efforts in support of these missions. MAPIR observes naturally-emitted radiation from the ground primarily for remote sensing of land surface brightness temperature from which we can retrieve soil moisture and possibly surface or water temperature and ocean salinity. MAPIR has achieved Technical Readiness Level 6 with flight heritage on two very different aircraft, the NASA P-3B, and a Piper Navajo.

  8. 23 CFR 772.3 - Noise standards.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Noise standards. 772.3 Section 772.3 Highways FEDERAL... OF HIGHWAY TRAFFIC NOISE AND CONSTRUCTION NOISE § 772.3 Noise standards. The highway traffic noise prediction requirements, noise analyses, noise abatement criteria, and requirements for informing...

  9. 23 CFR 772.3 - Noise standards.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Noise standards. 772.3 Section 772.3 Highways FEDERAL... OF HIGHWAY TRAFFIC NOISE AND CONSTRUCTION NOISE § 772.3 Noise standards. The highway traffic noise prediction requirements, noise analyses, noise abatement criteria, and requirements for informing...

  10. Discovery of Polarized Emission from Two Soft X-ray-emitting Intermediate Polars: UU Col and NY Lup

    NASA Astrophysics Data System (ADS)

    Katajainen, S.; Butters, O.; Norton, A. J.; Lehto, H. J.; Piirola, V.; Berdyugin, A.

    2010-11-01

    We aim to investigate the magnetic field strengths and cyclotron emission of the two soft X-ray-emitting intermediate polars (IPs) UU Col and NY Lup. We study the connection between polars and soft X-ray-emitting IPs by searching for evidence of circularly polarized light in these two systems, which may be examples of progenitors of polars. We carried out photopolarimetric observations of our targets using the Very Large Telescope (UT2) and FORS1 at Paranal. Imaging polarimetry with good signal-to-noise and relatively high time resolution is possible for these targets using such a large telescope. Detection of circular polarization, modulated according to a white dwarf (WD) spin period, is clear evidence of cyclotron emission processes near the WD surface. The color dependence of the polarization allows us to make estimates of the magnetic field strength. We found that both UU Col and NY Lup emit circularly polarized light in the B and I bands, modulated at the spin period of the WD in each case. We add further confirmation to the idea that soft X-ray-emitting IPs emit circularly polarized light and that cyclotron emission plays an important role in these systems. This also suggests that some soft X-ray-emitting IPs might be progenitors of polars.

  11. DISCOVERY OF POLARIZED EMISSION FROM TWO SOFT X-RAY-EMITTING INTERMEDIATE POLARS: UU Col AND NY Lup

    SciTech Connect

    Katajainen, S.; Lehto, H. J.; Berdyugin, A.; Butters, O.; Norton, A. J.; Piirola, V.

    2010-11-20

    We aim to investigate the magnetic field strengths and cyclotron emission of the two soft X-ray-emitting intermediate polars (IPs) UU Col and NY Lup. We study the connection between polars and soft X-ray-emitting IPs by searching for evidence of circularly polarized light in these two systems, which may be examples of progenitors of polars. We carried out photopolarimetric observations of our targets using the Very Large Telescope (UT2) and FORS1 at Paranal. Imaging polarimetry with good signal-to-noise and relatively high time resolution is possible for these targets using such a large telescope. Detection of circular polarization, modulated according to a white dwarf (WD) spin period, is clear evidence of cyclotron emission processes near the WD surface. The color dependence of the polarization allows us to make estimates of the magnetic field strength. We found that both UU Col and NY Lup emit circularly polarized light in the B and I bands, modulated at the spin period of the WD in each case. We add further confirmation to the idea that soft X-ray-emitting IPs emit circularly polarized light and that cyclotron emission plays an important role in these systems. This also suggests that some soft X-ray-emitting IPs might be progenitors of polars.

  12. Refraction of Sound Emitted Near Solid Boundaries from a Sheared Jet

    NASA Technical Reports Server (NTRS)

    Dill, Loren H.; Oyedrian, Ayo A.; Krejsa, Eugene A.

    1998-01-01

    A mathematical model is developed to describe the sound emitted from an arbitrary point within a turbulent flow near solid boundaries. A unidirectional, transversely sheared mean flow is assumed, and the cross-section of the cold jet is of arbitrary shape. The analysis begins with Lilley's formulation of aerodynamic noise and, depending upon the specific model of turbulence used, leads via Fourier analysis to an expression for the spectral density of the intensity of the far-field sound emitted from a unit volume of turbulence. The expressions require solution of a reduced Green's function of Lilley's equation as well as certain moving axis velocity correlations of the turbulence. Integration over the entire flow field is required in order to predict the sound emitted by the complete flow. Calculations are presented for sound emitted from a plugflow jet exiting a semi-infinite flat duct. Polar plots of the far-field directivity show the dependence upon frequency and source position within the duct. Certain model problems are suggested to investigate the effect of duct termination, duct geometry, and mean flow shear upon the far-field sound.

  13. The Traffic Noise Index: A Method of Controlling Noise Nuisance.

    ERIC Educational Resources Information Center

    Langdon, F. J.; Scholes, W. E.

    This building research survey is an analysis of the social nuisance caused by urban motor ways and their noise. The Traffic Noise Index is used to indicate traffic noises and their effects on architectural designs and planning, while suggesting the need for more and better window insulation and acoustical barriers. Overall concern is for--(1)…

  14. Jet engine noise source and noise footprint computer programs

    NASA Technical Reports Server (NTRS)

    Dunn, D. G.; Peart, N. A.; Miller, D. L.; Crowley, K. C.

    1972-01-01

    Calculation procedures are presented for predicting maximum passby noise levels and contours (footprints) of conventional jet aircraft with or without noise suppression devices. The procedures have been computerized and a user's guide is presented for the computer programs to be used in predicting the noise characteristics during aircraft takeoffs, fly-over, and/or landing operations.

  15. The noise emitted by turbulent jets in close proximity to solid surfaces

    NASA Astrophysics Data System (ADS)

    Carpenter, P. W.; Parsons, C.

    1986-07-01

    The present calculations of basic directivity patterns for randomly oriented longitudinal and lateral quadrupole types near a rigid plane indicate substantial differences between the two types. By applying Lighthill's (1954) acoustic analogy and extending the Ribner (1969) modeling method for acoustic sources, the basic directivity pattern of the sound generated by a unit volume of jet-type shear layer turbulence near an infinite grid plane is calculated and found to be very different from the corresponding elliptical one obtained by unit volume of free-field shear layer turbulence. The theory is presently applied to an actual turbulent shear flow, in the form of a plane, two-dimensional wall jet, basic aeroacoustic predictions are thereby obtained.

  16. Frequency spectrum of the noise emitted by two interacting cavitation bubbles in strong acoustic fields.

    PubMed

    Jiang, Liang; Liu, Fengbing; Chen, Haosheng; Wang, Jiadao; Chen, Darong

    2012-03-01

    The dynamics and acoustic emission of two interacting cavitation bubbles exposed to strong acoustic fields with a frequency of 515 KHz are investigated numerically in this paper. After comparing the dynamics of a single bubble excited by the given pressure waves, bubbles with ambient radii of 2 and 5 μm were chosen to be studied to discuss the influence of the mutual bubble-bubble interaction on the dynamic behaviors and acoustic emission of the bubbles. The results show that, aside from the external driving pressure waves, the interaction between the bubbles imposes an extra nonlinear effect on the oscillations of the bubbles and that the dynamics of the smaller bubble could be suppressed gradually with the enhancement of this mutual interaction by decreasing the distance between the bubbles. Moreover, the improvement in the oscillation nonlinearity of the bubbles due to the change in the ambient circumstance could readily be observed from the frequency spectra of the bubbles' acoustic emission, which interprets the change by exhibiting an appropriate development of the subharmonics, the ultraharmonics, and the broadband component.

  17. Trends in aircraft noise control

    NASA Technical Reports Server (NTRS)

    Hubbard, H. H.; Conrad, E. W.

    1975-01-01

    Flight vehicles are characterized according to their manner of operation and type of propulsion system; and their associated sources of noise are identified. Available noise reduction technology as it relates to engine cycle design and to powerplant component design is summarized. Such components as exhaust jets, fans, propellers, rotors, blown flaps, and reciprocating-engine exhausts are discussed, along with their noise reduction potentials. Significant aircraft noise reductions are noted to have been accomplished by the application of available technology in support of noise certification rules. Further noise reductions to meet more stringent future noise regulations will require substantial additional technology developments. Improved analytical prediction methods, and well-controlled validation experiments supported by advanced-design aeroacoustic facilities, are required as a basis for an effective integrated systems approach to aircraft noise control.

  18. High noise immunity one shot

    NASA Technical Reports Server (NTRS)

    Schaffer, G. L.

    1972-01-01

    Multivibrator circuit, which includes constant current source, isolates line noise from timing circuitry and field effect transistor controls circuit's operational modes. Circuit has high immunity to supply line noise.

  19. Dynamic Range of Vertical Cavity Surface Emitting Lasers in Multimode Links

    SciTech Connect

    Lee, H.L.T.; Dalal, R.V.; Ram, R.J.; Choquette, K.D.

    1999-07-07

    The authors report spurious free dynamic range measurements of 850nm vertical cavity surface emitting lasers in short multimode links for radio frequency communication. For a 27m fiber link, the dynamic range at optimal bias was greater than 95dB-Hz{sup 2/3} for modulation frequencies between 1 and 5.5 GHz, which exceeds the requirements for antenna remoting in microcellular networks. In a free space link, they have measured the highest dynamic range in an 850nm vertical cavity surface emitting laser of 113dB-Hz{sup 2/3} at 900MHz. We have also investigated the effects of modal noise and differential mode delay on the dynamic range for longer lengths of fiber.

  20. Thunderstorms and ground-based radio noise as observed by radio astronomy Explorer 1

    NASA Technical Reports Server (NTRS)

    Caruso, J. A.; Herman, J. R.

    1973-01-01

    Radio Astronomy Explorer (RAE) data were analyzed to determine the frequency dependence of HF terrestrial radio noise power. RAE observations of individual thunderstorms, mid-ocean areas, and specific geographic regions for which concommitant ground based measurements are available indicate that noise power is a monotonically decreasing function of frequency which conforms to expectations over the geographic locations and time periods investigated. In all cases investigated, active thunderstorm regions emit slightly higher power as contrasted to RAE observations of the region during meteorologically quiet periods. Noise levels are some 15 db higher than predicted values over mid-ocean, while in locations where ground based measurements are available a maximum deviation of 5 db occurs. Worldwide contour mapping of the noise power at 6000 km for five individual months and four observing frequencies, examples of which are given, indicate high noise levels over continental land masses with corresponding lower levels over ocean regions.

  1. Bats perceptually weight prey cues across sensory systems when hunting in noise.

    PubMed

    Gomes, D G E; Page, R A; Geipel, I; Taylor, R C; Ryan, M J; Halfwerk, W

    2016-09-16

    Anthropogenic noise can interfere with environmental information processing and thereby reduce survival and reproduction. Receivers of signals and cues in particular depend on perceptual strategies to adjust to noisy conditions. We found that predators that hunt using prey sounds can reduce the negative impact of noise by making use of prey cues conveyed through additional sensory systems. In the presence of masking noise, but not in its absence, frog-eating bats preferred and were faster in attacking a robotic frog emitting multiple sensory cues. The behavioral changes induced by masking noise were accompanied by an increase in active localization through echolocation. Our findings help to reveal how animals can adapt to anthropogenic noise and have implications for the role of sensory ecology in driving species interactions. PMID:27634533

  2. Impact of banning of two-stroke engines on airborne particulate matter concentrations in Dhaka, Bangladesh.

    PubMed

    Begum, Bilkis A; Biswas, Swapan K; Hopke, Philip K

    2006-01-01

    Vehicular air pollution is common in growing metropolitan areas throughout the world. Vehicular emissions of fine particles are particularly harmful because they occur near ground level, close to where people live and work. Two-stroke engines represented an important contribution to the motor vehicle emissions where they constitute approximately half of the total vehicle fleet in Dhaka city. Two-stroke engines have lower fuel efficiency than four-stroke engines, and they emit as much of an order of magnitude and more particulate matter (PM) than four-stroke engines of similar size. To eliminate their impact on air quality, the government of Bangladesh promulgated an order banning all two-stroke engines from the roads in Dhaka starting on December 31, 2002. The effect of the banning of two-stroke engines on airborne PM was studied at the Farm Gate air quality-monitoring station in Dhaka (capital of Bangladesh), a hot spot with very high-pollutant concentrations because of its proximity to major roadways. The samples were collected using a "Gent" stacked filter unit in two fractions of 0-2.2 microm and 2.2-10 microm sizes. Samples of fine and coarse fractions of airborne PM collected from 2000 to 2004 were studied. It has been found that the fine PM and black carbon concentrations decreased from the previous years because of the banning of two-stroke engine baby taxies.

  3. Characterization of airborne ice-nucleation-active bacteria and bacterial fragments

    NASA Astrophysics Data System (ADS)

    Šantl-Temkiv, Tina; Sahyoun, Maher; Finster, Kai; Hartmann, Susan; Augustin-Bauditz, Stefanie; Stratmann, Frank; Wex, Heike; Clauss, Tina; Nielsen, Niels Woetmann; Sørensen, Jens Havskov; Korsholm, Ulrik Smith; Wick, Lukas Y.; Karlson, Ulrich Gosewinkel

    2015-05-01

    Some bacteria have the unique capacity of synthesising ice-nucleation-active (INA) proteins and exposing them at their outer membrane surface. As INA bacteria enter the atmosphere, they may impact the formation of clouds and precipitation. We studied members of airborne bacterial communities for their capacity to catalyse ice formation and we report on the excretion of INA proteins by airborne Pseudomonas sp. We also observed for the first time that INA biological fragments <220 nm were present in precipitation samples (199 and 482 INA fragments per L of precipitation), which confirms the presence of submicron INA biological fragments in the atmosphere. During 14 precipitation events, strains affiliated with the genus Pseudomonas, which are known to carry ina genes, were dominant. A screening for INA properties revealed that ∼12% of the cultivable bacteria caused ice formation at ≤-7 °C. They had likely been emitted to the atmosphere from terrestrial surfaces, e.g. by convective transport. We tested the ability of isolated INA strains to produce outer membrane vesicles and found that two isolates could do so. However, only very few INA vesicles were released per INA cell. Thus, the source of the submicron INA proteinaceous particles that we detected in the atmosphere remains to be elucidated.

  4. Airborne infectious disease and the suppression of pulmonary bioaerosols.

    PubMed

    Fiegel, Jennifer; Clarke, Robert; Edwards, David A

    2006-01-01

    The current understanding of airborne pathogen spread in relation to the new methods of suppressing exhaled bioaerosols using safe surface-active materials, such as isotonic saline, is reviewed here. We discuss the physics of bioaerosol generation in the lungs, what is currently known about the relationship between expired bioaerosols and airborne infectious disease and current methods of airborne infectious disease containment. We conclude by reviewing recent experiments that suggest the delivery of isotonic saline can significantly diminish exhaled aerosol--generated from airway lining fluid in the course of natural breathing. We also discuss these implications in relation to airborne infectious disease control.

  5. Raytheon low temperature RSP2 cryocooler airborne testing

    NASA Astrophysics Data System (ADS)

    Schaefer, B. R.; Bellis, L.; Ellis, M. J.; Conrad, T. J.

    2014-01-01

    The Raytheon Cryocooler Product Line tested the Low Temperature Stirling / Pulse Tube Hybrid 2-Stage (LTRSP2) cryocooler for an airborne application during 2012. Several tests were carried out to verify the ability of the machine to operate in an airborne environment. The vacuum level and heat rejection surface temperatures were varied to determine the performance over the excursions. Vibration testing was performed to prove that the LT-RSP2 cryocooler can operate on an airborne platform. This paper will present the results of the airborne characterization testing.

  6. Raytheon low temperature RSP2 cryocooler airborne testing

    NASA Astrophysics Data System (ADS)

    Schaefer, B. R.; Bellis, L.; Ellis, M. J.; Conrad, T. J.

    2013-09-01

    The Raytheon Cryocooler Product Line tested the Low Temperature Stirling / Pulse Tube Hybrid 2-Stage (LTRSP2) cryocooler for an airborne application during 2012. Several tests were carried out to verify the ability of the machine to operate in an airborne environment. The vacuum level and heat rejection surface temperatures were varied to determine the performance over the excursions. Vibration testing was performed to prove that the LT-RSP2 cryocooler can operate on an airborne platform. This paper will present the results of the airborne characterization testing.

  7. Airborne lidar experiments at the Savannah River Plant

    NASA Technical Reports Server (NTRS)

    Krabill, William B.; Swift, Robert N.

    1985-01-01

    The results of remote sensing experiments at the Department of Energy (DOE) Savannah River Nuclear Facility utilizing the NASA Airborne Oceanographic Lidar (AOL) are presented. The flights were conducted in support of the numerous environmental monitoring requirements associated with the operation of the facility and for the purpose of furthering research and development of airborne lidar technology. Areas of application include airborne laser topographic mapping, hydrologic studies using fluorescent tracer dye, timber volume estimation, baseline characterization of wetlands, and aquatic chlorophyll and photopigment measurements. Conclusions relative to the usability of airborne lidar technology for the DOE for each of these remote sensing applications are discussed.

  8. Collection and Analysis of Aircraft Emitted Particles

    NASA Technical Reports Server (NTRS)

    Wilson, James Charles

    1999-01-01

    The University of Denver Aerosol Group proposed to adapt an impactor system for the collection of particles emitted by aircraft. The collection substrates were electron microscope grids which were analyzed by Dr. Pat Sheridan using a transmission electron microscope. The impactor was flown in the SNIFF behind aircraft and engine emissions were sampled. This report details the results of that work.

  9. Light-Emitting Diodes: Solving Complex Problems

    ERIC Educational Resources Information Center

    Planinšic, Gorazd; Etkina, Eugenia

    2015-01-01

    This is the fourth paper in our Light-Emitting Diodes series. The series aims to create a systematic library of LED-based materials and to provide readers with the description of experiments and the pedagogical treatment that would help their students construct, test, and apply physics concepts and mathematical relations. The first paper provided…

  10. Light-Emitting Diodes: A Hidden Treasure

    ERIC Educational Resources Information Center

    Planinšic, Gorazd; Etkina, Eugenia

    2014-01-01

    LEDs, or light-emitting diodes, are cheap, easy to purchase, and thus commonly used in physics instruction as indicators of electric current or as sources of light (Fig. 1). In our opinion LEDs represent a unique piece of equipment that can be used to collect experimental evidence, and construct and test new ideas in almost every unit of a general…

  11. Demonstrating the Light-Emitting Diode.

    ERIC Educational Resources Information Center

    Johnson, David A.

    1995-01-01

    Describes a simple inexpensive circuit which can be used to quickly demonstrate the basic function and versatility of the solid state diode. Can be used to demonstrate the light-emitting diode (LED) as a light emitter, temperature sensor, light detector with both a linear and logarithmic response, and charge storage device. (JRH)

  12. Light-Emitting Diodes: Learning New Physics

    ERIC Educational Resources Information Center

    Planinšic, Gorazd; Etkina, Eugenia

    2015-01-01

    This is the third paper in our Light-Emitting Diodes series. The series aims to create a systematic library of LED-based materials and to provide the readers with the description of experiments and pedagogical treatment that would help their students construct, test, and apply physics concepts and mathematical relations. The first paper, published…

  13. Bioinspired Hybrid White Light-Emitting Diodes.

    PubMed

    Weber, Michael D; Niklaus, Lukas; Pröschel, Marlene; Coto, Pedro B; Sonnewald, Uwe; Costa, Rubén D

    2015-10-01

    The first bioinspired hybrid white-light-emitting diodes (bio-HLEDs) featuring protein cascade coatings are presented. For easy fabrication a new strategy to stabilize proteins in rubber-like material was developed. The synergy between the excellent features of fluorescent proteins and the easily processed rubber produces bio-HLEDs with less than 10% loss in luminous efficiency over 100 hours.

  14. Do Atoms Really "Emit" Absorption Lines?

    ERIC Educational Resources Information Center

    Brecher, Kenneth

    1991-01-01

    Presents three absorption line sources that enhance student understanding of the phenomena associated with the interaction of light with matter and help dispel the misconception that atoms "emit" absorption lines. Sources include neodymium, food coloring and other common household liquids, and fluorescent materials. (MDH)

  15. Fragranced consumer products: Chemicals emitted, ingredients unlisted

    SciTech Connect

    Steinemann, Anne C.; MacGregor, Ian C.; Gordon, Sydney M.; Gallagher, Lisa G.; Davis, Amy L.; Ribeiro, Daniel S.; Wallace, Lance A.

    2011-04-15

    Fragranced consumer products are pervasive in society. Relatively little is known about the composition of these products, due to lack of prior study, complexity of formulations, and limitations and protections on ingredient disclosure in the U.S. We investigated volatile organic compounds (VOCs) emitted from 25 common fragranced consumer products-laundry products, personal care products, cleaning supplies, and air fresheners-using headspace analysis with gas chromatography/mass spectrometry (GC/MS). Our analysis found 133 different VOCs emitted from the 25 products, with an average of 17 VOCs per product. Of these 133 VOCs, 24 are classified as toxic or hazardous under U.S. federal laws, and each product emitted at least one of these compounds. For 'green' products, emissions of these compounds were not significantly different from the other products. Of all VOCs identified across the products, only 1 was listed on any product label, and only 2 were listed on any material safety data sheet (MSDS). While virtually none of the chemicals identified were listed, this nonetheless accords with U.S. regulations, which do not require disclosure of all ingredients in a consumer product, or of any ingredients in a mixture called 'fragrance.' Because the analysis focused on compounds emitted and listed, rather than exposures and effects, it makes no claims regarding possible risks from product use. Results of this study contribute to understanding emissions from common products, and their links with labeling and legislation.

  16. Aroma chemical emitted from Gerris paludum insularis.

    PubMed

    Ono, Toshirou; Miyazawa, Mitsuo

    2004-06-01

    An aroma chemical emitted from Gerris paludum insularis was analyzed by means of GC and GC-MS. The main constituent was identified as iso amyl alcohol (3-methyl-1-butanol). The chemical showed a characteristic aroma of Gerris paludum insularis.

  17. Sounds Alive: A Noise Workbook.

    ERIC Educational Resources Information Center

    Dickman, Donna McCord

    Sarah Screech, Danny Decibel, Sweetie Sound and Neil Noisy describe their experiences in the world of sound and noise to elementary students. Presented are their reports, games and charts which address sound measurement, the effects of noise on people, methods of noise control, and related areas. The workbook is intended to stimulate students'…

  18. School Noise and Its Control

    ERIC Educational Resources Information Center

    Ikenberrgy, Larry D.

    1974-01-01

    Sources of noises affecting schools and their hindrance of learning are presented. Noise levels for different activities are tabled and possible methods for controlling such noises are suggested. Internal to the school, shop and music levels are the most severe. More care in site selection and design considerations are recommended. (LS)

  19. Rotary wing aerodynamically generated noise

    NASA Technical Reports Server (NTRS)

    Schmitz, F. J.; Morse, H. A.

    1982-01-01

    The history and methodology of aerodynamic noise reduction in rotary wing aircraft are presented. Thickness noise during hover tests and blade vortex interaction noise are determined and predicted through the use of a variety of computer codes. The use of test facilities and scale models for data acquisition are discussed.

  20. Practical Ranges of Loudness Levels of Various Types of Environmental Noise, Including Traffic Noise, Aircraft Noise, and Industrial Noise

    PubMed Central

    Salomons, Erik M.; Janssen, Sabine A.

    2011-01-01

    In environmental noise control one commonly employs the A-weighted sound level as an approximate measure of the effect of noise on people. A measure that is more closely related to direct human perception of noise is the loudness level. At constant A-weighted sound level, the loudness level of a noise signal varies considerably with the shape of the frequency spectrum of the noise signal. In particular the bandwidth of the spectrum has a large effect on the loudness level, due to the effect of critical bands in the human hearing system. The low-frequency content of the spectrum also has an effect on the loudness level. In this note the relation between loudness level and A-weighted sound level is analyzed for various environmental noise spectra, including spectra of traffic noise, aircraft noise, and industrial noise. From loudness levels calculated for these environmental noise spectra, diagrams are constructed that show the relation between loudness level, A-weighted sound level, and shape of the spectrum. The diagrams show that the upper limits of the loudness level for broadband environmental noise spectra are about 20 to 40 phon higher than the lower limits for narrowband spectra, which correspond to the loudness levels of pure tones. The diagrams are useful for assessing limitations and potential improvements of environmental noise control methods and policy based on A-weighted sound levels. PMID:21776205