Science.gov

Sample records for emitted airborne noise

  1. Measurement of the airborne noise and the noise at the operator's position emitted by the ECOTRAC V-1033 F forest tractor.

    PubMed

    Goglia, V; Beljo, R; Gnjilac, D

    1995-03-01

    The paper reports on the measurement procedure and results of measurements of the airborne noise emitted by the ECOTRAC V-1033 F forest tractor. The measurements were carried out in accordance with the International Standards ISO 4872 and 362 for the stationary test condition. The paper further reports on noise measurements at the tractor operator's position conducted in accordance with the International Standards ISO 5131 and 6394. All measurements were performed using the Bruel & Kjaer 4165 type microphone and the 2209 type sound level meter from the same manufacturer. According to ISO 4872, 6393 and 362 the noise level did not exceed the limit values. However, the noise level at the operator's position at full load and at nominal load exceeded the limits. Measures to be undertaken should aim at protecting the driver and improving the cab characteristics. PMID:7575143

  2. 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.

  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. The prediction of airborne and structure-borne noise potential for a tire

    NASA Astrophysics Data System (ADS)

    Sakamoto, Nicholas Y.

    Tire/pavement interaction noise is a major component of both exterior pass-by noise and vehicle interior noise. The current testing methods for ranking tires from loud to quiet require expensive equipment, multiple tires, and/or long experimental set-up and run times. If a laboratory based off-vehicle test could be used to identify the airborne and structure-borne potential of a tire from its dynamic characteristics, a relative ranking of a large group of tires could be performed at relatively modest expense. This would provide a smaller sample set of tires for follow-up testing and thus save expense for automobile OEMs. The focus of this research was identifying key noise features from a tire/pavement experiment. These results were compared against a stationary tire test in which the natural response of the tire to a forced input was measured. Since speed was identified as having some effect on the noise, an input function was also developed to allow the tires to be ranked at an appropriate speed. A relative noise model was used on a second sample set of tires to verify if the ranking could be used against interior vehicle measurements. While overall level analysis of the specified spectrum had mixed success, important noise generating features were identified, and the methods used could be improved to develop a standard off-vehicle test to predict a tire's noise potential.

  10. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    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.

  12. Light-emitting diode quality investigation via low-frequency noise characteristics

    NASA Astrophysics Data System (ADS)

    Palenskis, Vilius; Matukas, Jonas; Pralgauskaitė, Sandra

    2010-08-01

    There are presented a comprehensive investigation of noise characteristics (the fluctuations spectra of both the emitted light power and the voltage of light-emitting diodes (LEDs) at constant direct current (d.c.), and their simultaneous cross-correlation factor) for nitride-based green (InGaN) and phosphide-based red (AlInGaP) LEDs. The noise characteristics of LEDs before aging and during their aging have been carried out. It is shown, that large level of electrical fluctuations of the red LEDs did not show on high defectiveness of the active layer. These electrical fluctuations are related with the charge carrier recombination and capture processes in defects outside the active region, and they only weakly influence the emitted light power fluctuations. On the contrary, the large cross-correlation factor for the green LEDs shows that low-frequency electrical and optical noises are mainly due to defects in the active layer and its interfaces. It is shown, that during 1800 h aging the red LEDs characteristics are more stabile: their light output power has negligible changes, while analogical characteristics for the green LEDs gradually decreases over 30%.

  13. Spatial resolution and noise in organic light-emitting diode displays for medical imaging applications.

    PubMed

    Yamazaki, Asumi; Wu, Chih-Lei; Cheng, Wei-Chung; Badano, Aldo

    2013-11-18

    We report on the resolution and noise characteristics of handheld and workstation organic light-emitting diode (OLED) displays in comparison with liquid crystal displays (LCDs). The results demonstrate advantages, in terms of sharpness, of handheld OLED displays with modulation transfer function (MTF) values exceeding 0.60 at the Nyquist frequencies. The OLED workstation included in this study exhibits significant signal contamination among adjacent pixels resulting in degraded resolution performance indicated by horizontal and vertical MTF values of 0.13 and 0.24 at the Nyquist frequency. On the other hand, its noise characteristics are superior to the LCD workstation tested. While the noise power spectral (NPS) values of the OLED workstation are 8.0×10(-6) mm2 at 1 mm(-1), the LCD workstation has NPS values of 2.6×10(-5) mm2. Although phone-size OLED displays have superior resolution and noise per pixel, the perceived resolution characteristics at appropriate viewing distances are inferior to tablet-size and workstation LCDs. In addition, our results show some degree of dependency of the resolution and noise on luminance level and viewing orientation. We also found a slightly degraded resolution and increased low-frequency noise at off-normal orientations in the handheld displays. PMID:24514325

  14. Low frequency noise of gallium nitride-based deep ultraviolet light emitting diodes

    NASA Astrophysics Data System (ADS)

    Sawyer, Shayla Maya Louise

    This study covers the investigation of deep UV GaN-based light emitting diodes using low frequency noise characterization. Using this technique, device improvements were analyzed as feedback to developers and practical parameters were created for system use. AlGaN LEDs emit wavelengths into the deep UV spectral region (lambda < 290 nm). These devices are an integral component for applications including biological hazard detection systems, biological experimentation, food and water sterilization, non-line-of-sight short range communication, counterfeit identification, photolithography, and general white lighting. The current technological trend demonstrates a decrease in material quality and device performance with decreasing wavelength. However, progress has allowed for its commercialization in a relatively short period of time. Characterization of material and device improvements provides feedback for changes in development. Secondly, methods to determine the reliability and stability of these devices are essential to the applications for which they are used. One such method is through optical and current low frequency noise (LFN) measurements in which both system related parameters such as a signal-to-noise ratio for light sources and insight into the fundamental physics within the devices can be determined. The quality of the device can be compared before costly integration into systems that require low noise, high reliability, and optical stability. It not only quantifies performance limiting noise levels, but it is known to be a sensitive, nondestructive measure of material quality and reliability. The research highlighted in this thesis demonstrates a new measurement technique in analyzing the light intensity fluctuations through low frequency optical noise. From this work, a proposed figure-of-merit is presented. Low frequency current noise was performed as a well known indicator of material quality. Each technique compares LEDs grown by SET Inc. LEDs of

  15. 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.

  16. Signal to Noise Ratio Analysis of the Data from the Pulsed Airborne CO2 Lidar Measurements

    NASA Astrophysics Data System (ADS)

    Sun, X.; Abshire, J. B.; Riris, H.; Allan, G. R.; Hasselbrack, W. E.

    2009-12-01

    We are developing a differential absorption lidar (DIAL) for measuring the CO2 column concentrations from space for the ASCENDS mission. Our technique uses two pulsed laser transmitters to simultaneously measure the total column absorption by CO2 in 1570 nm band and O2 extinction in the Oxygen A-band by periodically stepping the laser wavelength at predetermined wavelengths across the absorption lines. The reflected laser signals from the surface and clouds are collected by the receiver telescope and detected by a set of single photon counting detectors. We used pulsed lasers and time resolved photon detection to distinguish the surface echoes from cloud and aerosol backscattering and to measure the column height. . The total column absorption at a given wavelength is determined from the ratio of the received laser pulse energy to the transmitted energy. The column gas concentrations and the spectral line shape are determined from curve fitting of the column absorptions as a function of the wavelength. We have built an airborne lidar to demonstrate the CO2 column measurement technique from the NASA Lear-25 aircraft. The airborne lidar scans the laser wavelength across the CO2 absorption line in 20 steps. The line scan rate is 450 Hz, the laser pulse energy is 25 uJ, and laser pulse widths are 1 usec. The backscatter photons are collected by a 20 cm telescope and detected by a near infrared photomultiplier tube. The detected photons are binned according to their arrival times with the use of a multichannel scaler. Several airborne measurements were conducted during October and December 2008, and August 2009 with many hours of CO2 column measurement data at the 1571.4, 1572.02 and 1572.33 nm CO2 absorption lines. The measurements were made over a variety of land and water surfaces and some through thin clouds. We also made several improvements to the instrument for the later flights. Measurements from early flights showed the receiver signal and noise levels were

  17. Characterization of phosphorescent organic light-emitting diodes using current noise cross-correlated spectroscopy

    NASA Astrophysics Data System (ADS)

    Kamdem Djidjou, Thaddee; Li, Sergey; Rogachev, Andrey

    2014-03-01

    Carrier injection and transport mechanism in small-molecule phosphorescent organic light-emitting diodes (PhOLED) have been investigated using current noise spectroscopy. The PhOLED devices studied consist of multilayers having the structure ITO / NPB / NPB:Irphq / Balq / Bpen:CsCO3/ Al. We found that in high bias regime, the noise spectral density can be described by two terms, 1/ f1.3 and 1/f2.8. The first term disappears below 2.5 V, as does the luminance; this suggests that this term is related to bimolecular recombination in the devices. The second term is more pronounced al low frequencies and its magnitude is linearly proportional to the current in the device. This term, which exists in all bias range, is likely related to the presence of traps with a distributed time constant. For applied voltages greater than 2.4 V, the frequency-independent noise is dominated by the shot noise. The Fano factor is one in the range 2.4 - 2.5 V, and decreases to a constant value of 0.4 at higher biases. This indicates the presence of a barrier for carrier injection into the device. Our overall results confirm the utility of noise measurements for OLED characterization.

  18. Evaluation of the noise emitted by the condenser of a household refrigerator

    NASA Astrophysics Data System (ADS)

    Llado Paris, Juan; Sanchez Tabuenca, Beatriz

    2002-11-01

    It has been determined that the noise emitted by a household refrigerator is the addition of two main sources: the direct noise emitted by both compressor shells, and the structural noise caused by the condenser vibration, that depends on the coolant excitation, on its own structural rigidity, and on the rigidity of the joints that fix it to the back panel of the refrigerator and to the compressors. The decrease of the sound power due to the condenser implies the modification of their mechanical and geometric characteristics: shape, thickness, type of material, redesign of the joints to the back panel of the refrigerator, and optimization of their number and location, etc., to achieve a less rigid structure. From these proposals, a new more flexible design of the joints was tested because it was the faster one to implement due to the refrigerator efficiency is not altered. A sound power reduction of about 2 dBA, was obtained. Finally, the location and number of the joints were optimized, getting the same sound power level with three than with four joints. (To be presented in Spanish.)

  19. 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.

  20. 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

  1. 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.)

  2. 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.

  3. 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

  4. 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.

  5. Characterization and Control of Airborne Particles Emitted During Production of Epoxy / Carbon Nanotube Nanocomposites

    PubMed Central

    Cena, Lorenzo G.; Peters, Thomas M.

    2016-01-01

    This work characterized airborne particles that were generated from the weighing of bulk, multi-wall 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 ratiô1). The particles generated during sanding were predominately 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/m3) compared to those with no LEV (GM = 2.68 μg/m3) or those when sanding was performed inside the fume hood (GM = 21.4 μg/m3; 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

  6. 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

  7. Gross alpha, gross beta activities and gamma emitting radionuclides composition of airborne particulate samples in an oceanic island

    NASA Astrophysics Data System (ADS)

    Hernández, F.; Hernández-Armas, J.; Catalán, A.; Fernández-Aldecoa, J. C.; Karlsson, L.

    The radiometric compositions of airborne particulate samples, collected weekly during a 4 years period (1 January 2000 till 31 December 2003) at a site located 310 m a.s.l. in Tenerife (Canary Islands), are analysed in this paper. To do this, measurements of gross alpha, gross beta, 7Be, 210Pb, 228Ac, 226Ra, 212Pb, 214Pb, 208Tl, 214Bi, 235U, 40K, 131I and 137Cs concentrations were carried out in 376 cellulose and polypropylene filters. The time variations of the different radionuclides concentrations have been discussed in relation with various meteorological factors and the mean values have been compared to those published in recent literature for other sites located at the same altitude but different latitudes. The weekly activities of 7Be correlated linearly with the 210Pb activities ( R=0.59). In disagreement with other published studies, the 7Be activities did not correlate ( R=-0.05) with the temperature and maximum values were not found during summer season. The gross beta activities showed correlations with the gross alpha ( R=0.72) and 210Pb activities ( R=0.52), but not with the 7Be ( R=0.16). The anthropogenic radionuclide 131I, emitted from a nearby hospital, was detected slightly above detection limits (1.73×10 -6 Bq m -3) in 88 of the 210 weeks of measurement considered in this work. 137Cs was detected in 31 of those weeks. The 4-year average calculated for 7Be and 210Pb were 3 and 0.3 mBq m -3, respectively. These values are lower than those expected for a site at comparable latitude and altitude. In general, the radionuclides which appeared most frequently in the airborne particulate filters ( 7Be, 210Pb, 212Pb and 40K), did not correlate significantly with any of the meteorological parameters considered: rainfall, temperature, pressure, relative humidity, visibility, wind speed and direction. Therefore, no predictive model could be established with the available data as it has been done for continental sites. The long-range transport of aerosols

  8. 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)…

  9. 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.

  10. 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).

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. 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

  19. Intensity- and phase-noise correlations in a dual-frequency vertical-external-cavity surface-emitting laser operating at telecom wavelength

    NASA Astrophysics Data System (ADS)

    De, Syamsundar; Baili, Ghaya; Bouchoule, Sophie; Alouini, Mehdi; Bretenaker, Fabien

    2015-05-01

    The amplitude and phase noises of a dual-frequency vertical-external-cavity surface-emitting laser (DF-VECSEL) operating at telecom wavelength are theoretically and experimentally investigated in detail. In particular, the spectral behavior of the correlation between the intensity noises of the two modes of the DF-VECSEL is measured. Moreover, the correlation between the phase noise of the radio-frequency beat note generated by optical mixing of the two laser modes with the intensity noises of the two modes is investigated. All these spectral behaviors of noise correlations are analyzed for two different values of the nonlinear coupling between the laser modes. We find that to describe the spectral behavior of noise correlations between the laser modes, it is of utmost importance to have precise knowledge about the spectral behavior of the pump noise, which is the dominant source of noise in the frequency range of interest (10 kHz to 35 MHz). Moreover, it is found that the noise correlation also depends on how the spatially separated laser modes of the DF-VECSEL intercept the noise from a multimode fiber-coupled laser diode used for pumping both the laser modes. To this aim, a specific experiment is reported which aims at measuring the correlations between different spatial regions of the pump beam. The experimental results are in excellent agreement with a theoretical model based on modified rate equations.

  20. Application of traditional cyclone with spray scrubber to remove airborne silica particles emitted from stone-crushing factories.

    PubMed

    Bahrami, Abdulrahman; Ghorbani, Farshid; Mahjub, Hossien; Golbabei, Farideh; Aliabadi, Mohsan

    2009-08-01

    The traditional cyclone with spray scrubber was developed for the removal of airborne silica particles from local exhaust ventilation (LEV). The objective of this research is to evaluate the efficiency of this process for removing silica particles in LEV. After designing and installing a traditional cyclone and spray scrubber, air samples were obtained at the inlet and outlet of the apparatus. The mass of each collected sample was determined gravimetrically using EPA method. The efficiency of the cyclone with spray scrubber for the removal of dust particles from the LEV system was determined to be in the range of 92-99%. There was a high correlation between the inlet concentration of dust particles and the efficiency of the apparatus. The total pressure across the system was 772.17-1120.90 Pa. It was concluded that a traditional cyclone with a spray scrubber can effectively remove a very high percentage of the incoming silica particles from an LEV. The total pressure drop across the current process is less than the pressure drop across other treatment equipment, which means that our process can effectively remove silica particles while using less electricity than other processes. PMID:19672019

  1. 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

  2. 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.

  3. Noise

    MedlinePlus

    Noise is all around you, from televisions and radios to lawn mowers and washing machines. Normally, you ... sensitive structures of the inner ear and cause noise-induced hearing loss. More than 30 million Americans ...

  4. 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.

  5. 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.

  6. 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.

  7. Validation of the GOSAT Thermal Infrared (TIR) Band using the University of Wisconsin airborne Scanning High-resolution Interferometer Sounder (S-HIS) and ground-based Atmospheric Emitted Radiance Interferometer (AERI) at Railroad Valley, Nevada

    NASA Astrophysics Data System (ADS)

    Knuteson, R.; kuze, A.; Shiomi, K.; Taylor, J. K.; Garms, E.; Roman, J.; Revercomb, H. E.; Tobin, D. C.; Gero, P.; Best, F. A.

    2011-12-01

    We provide a quantitative assessment of the calibration accuracy of the thermal infrared measurements from the Greenhouse Gases Observing SATellite (GOSAT), which was launched on January 23, 2009. Results will be presented comparing the observed emission spectra from the TANSO-FTS sensor onboard GOSAT to coincident observations from high altitude aircraft and ground-based spectrometers during the June 2011 Railroad Valley Vicarious Calibration and Validation campaign. The 2011 campaign was the third in a series of joint Japan/U.S. field measurements to assess the calibration of the GOSAT sensors and validate derived products of carbon dioxide and methane. As part of the 2011 campaign, the University of Wisconsin Scanning High-resolution Interferometer Sounder (S-HIS) successfully overflew Railroad Valley, Nevada onboard the high-altitude NASA ER-2 along with the Airborne Visible/InfraRed Imaging Spectrometer (AVIRIS) and the MODIS/ASTER Airborne Simulator (MASTER). The ER-2 overpass of Railroad Valley on June 20, 2011 was timed to coincide with an overpass of the GOSAT satellite at 21:19 UTC. A joint JPL/UWisc team provided coincident upper air observations of pressure, temperature, and water vapor using Vaisala radiosondes released from the center of the Railroad Valley dry lakebed (playa) for six GOSAT daytime overpasses and three nighttime overpasses between 19-26 June 2011. The University of Wisconsin also made ground-based measurements from the center of the playa during each GOSAT overpass with an Atmospheric Emitted Radiance Interferometer. The AERI was operated from a research vehicle with the capability to measure the upwelling surface radiance at three view angles and the downwelling atmospheric emission at two angles. The ground-based AERI provided accurate surface emissivity and surface temperature for use in forward model calculations of the satellite observed infrared emission between 6 and 17 microns.

  8. 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.

  9. Airborne ultraviolet imaging system for oil slick surveillance: oil-seawater contrast, imaging concept, signal-to-noise ratio, optical design, and optomechanical model.

    PubMed

    Shi, Zhenhua; Yu, Lei; Cao, Diansheng; Wu, Qingwen; Yu, Xiangyang; Lin, Guanyu

    2015-09-01

    The airborne ultraviolet imaging system, which assesses oil slick areas better than visible and infrared optical systems, was designed to monitor and track oil slicks in coastal regions. A model was built to achieve the upwelling radiance distribution of oil-covered sea and clean seawater, based on the radiance transfer software. With this model, the oil-seawater contrast, which affects the detection of oil-covered coastal areas, was obtained. The oil-seawater contrast, fundamental imaging concept, analog calculation of SNR, optical design, and optomechanical configuration of the airborne ultraviolet imaging system are illustrated in this paper. The study of an airborne ultraviolet imaging system with F-number 3.4 and a 40° field of view (FOV) in near ultraviolet channel (0.32-0.38 μm) was illustrated and better imaging quality was achieved. The ground sample distance (GSD) is from 0.35 to 0.7 m with flight height ranges from 0.5 to 1 km. Comparisons of detailed characteristics of the airborne ultraviolet imaging system with the corresponding characteristics of previous ultraviolet systems were tabulated, and these comparisons showed that this system can achieve a wide FOV and a relative high SNR. A virtual mechanical prototype and tolerances analysis are illustrated in this paper to verify the performance of fabrication and assembly of the ultraviolet system. PMID:26368888

  10. 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

  11. Fourth Airborne Geoscience Workshop

    NASA Technical Reports Server (NTRS)

    1991-01-01

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

  12. Airborne laser

    NASA Astrophysics Data System (ADS)

    Lamberson, Steven E.

    2002-06-01

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

  13. A theoretical model for airborne radars

    NASA Astrophysics Data System (ADS)

    Faubert, D.

    1989-11-01

    This work describes a general theory for the simulation of airborne (or spaceborne) radars. It can simulate many types of systems including Airborne Intercept and Airborne Early Warning radars, airborne missile approach warning systems etc. It computes the average Signal-to-Noise ratio at the output of the signal processor. In this manner, one obtains the average performance of the radar without having to use Monte Carlo techniques. The model has provision for a waveform without frequency modulation and one with linear frequency modulation. The waveform may also have frequency hopping for Electronic Counter Measures or for clutter suppression. The model can accommodate any type of encounter including air-to-air, air-to-ground (look-down) and rear attacks. It can simulate systems with multiple phase centers on receive for studying advanced clutter or jamming interference suppression techniques. An Airborne Intercept radar is investigated to demonstrate the validity and the capability of the model.

  14. Airborne radioactive contamination monitoring

    SciTech Connect

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

    1996-03-01

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

  15. 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.

  16. The battle against noise in industry

    NASA Astrophysics Data System (ADS)

    Iudin, E. Ia.

    The physiological effects of noise in manufacturing plants and other industrial facilities are discussed, and several common noise abatement methods are described. Consideration is given to the acoustic properties of three types of noise which are present in industrial plants: aerohydrodynamic noise; mechanical noise; and electromagnetic noise. Among the specific noise abatement techniques discussed are: sound isolation by means of noise-absorbant screens; insulation or noise-emitting media; and acoustic interference. The use of earplugs and external ear protectors for protection of individual workers in noisy work environments is also considered.

  17. 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.

  18. 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.

  19. 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.

  20. Airborne Gravimetry and Downward Continuation (Invited)

    NASA Astrophysics Data System (ADS)

    Jekeli, C.; Yang, H.; Kwon, J.

    2009-12-01

    Measuring the Earth’s gravity field using airborne instrumentation is fully operational and has been widely practiced for nearly three decades since its official debut in the early 1980s (S. Hammer: “Airborne Gravity is Here!”) coinciding with the precision kinematic positioning capability of GPS. Airborne gravimetry is undertaken for both efficient geophysical exploration purposes, as well as the determination of the regional geoid to aid in the modernization of height systems. Especially for the latter application, downward continuation of the data and combination with existing terrestrial gravimetry pose theoretical as well as practical challenges, which, on the other hand, create multiple processing possibilities. Downward continuation may be approached in various ways from the viewpoint of potential theory and the boundary-value problem to using gradients either estimated locally or computed from existing models. Logistical constraints imposed by the airborne survey, instrumental noise, and the intrinsic numerical instability of downward continuation all conspire to impact the final product in terms of achievable resolution and accuracy. In this paper, we review the theory of airborne gravimetry and the methodology of downward continuation, and provide a numerical comparison of possible schemes and their impact on geoid determination.

  1. Airborne oceanographic lidar system

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

    The characteristics of an Airborne Oceanographic Lidar (AOL) are given. The AOL system is described and its potential for various measurement applications including bathymetry and fluorosensing is discussed.

  2. The Caltech airborne submillimeter SIS receiver

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  3. 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.

  4. 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.

  5. Aeroacoustics: Jet noise, combustion and core engine noise

    NASA Technical Reports Server (NTRS)

    Schwartz, I. R.

    1976-01-01

    The papers in this volume deal essentially with the question whether the amplification of noise is due to the jet noise phenomenon or perhaps an interaction of airframe and core engine noise. In the area of jet noise suppression, various promising suppressor concepts are examined. The swirling flow jet noise suppressor is shown to provide significant noise reduction with minimal thrust losses. Progress in the aircraft engine core noise problem is reflected by seven research-type papers. Two possible mechanisms are seen to be responsible for core noise. One is the direct noise radiated from the turbulent combustion in the primary combuster and transmitted through the turbine, passing out the nozzle into the far field. The other mechanism is the noise that is emitted from hot spots being convected through the turbine. Which of these mechanisms (or perhaps both mechanisms) is responsible for core noise, and what are the coupling mechanisms of core engine noise and jet noise are the questions confronting researchers.

  6. 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.

  7. 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.

  8. Noise Pollution

    MedlinePlus

    ... here: EPA Home Air and Radiation Noise Pollution Noise Pollution This page has moved. You should be ... epa.gov/clean-air-act-overview/title-iv-noise-pollution Local Navigation Air & Radiation Home Basic Information ...

  9. Noise labeling in Brazil

    NASA Astrophysics Data System (ADS)

    de Araujo, Marco A. N.; Massarani, Paulo M.; de Azevedo, Jose A. J.; Gerges, Samir N. Y.

    2002-11-01

    The Brazilian Silence Program, created in 1990 by the Brazilian Ministry of Environment, advocates the production and use of equipment with lower noise level. The subcommittee of Noise Labeling of the Brazilian Committee of Certification is composed of INMETRO acoustic specialists to organize and implement the Brazilian Labeling Program. This subcommittee elaborated the label form and test procedure. The noise-labeling program will first concentrate on the following household devices, both manufactured in Brazil or imported from abroad; mixers, blenders, hairdryers, refrigerators, and vacuum cleaners. The label should contain the sound-power level in dBA. INMETRO or other credited laboratories are responsible for the measurements. The ISO 4871, 3740 (1 to 5), ISO 8960, and IEC 704 (1 to 4) and also the equivalent Brazilian standards are used for the measurements, such as ABNT NBR 13910-1. The main objective of the label is to inform the consumer about the emitted noise level. The label offers the noise parameter to be used by the consumer when comparing devices, considering price, performance, and now also noise. No restriction for noise level was established.

  10. Airborne gravity is here

    SciTech Connect

    Hammer, S.

    1982-01-11

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

  11. Noise reduction of a table saw

    NASA Astrophysics Data System (ADS)

    Carlson, John

    2002-05-01

    The National Institute for Occupational Safety and Health (NIOSH) is sponsoring a design project to address the noise levels that commonly exist at construction worksites. Through engineering control, the problem of noise emission from a table saw will be addressed. The noise emitting sources will be pinpointed using a sound pressure level meter. With this knowledge, the next step will be to reduce the sound pressure levels at the noise sources. This will be done by using noise reduction techniques such as insulation, and vibration dampening. The goal is to reduce the noise emission to a level between 85 and 90 dB(A).

  12. Toolsets for Airborne Data

    Atmospheric Science Data Center

    2015-04-02

    article title:  Toolsets for Airborne Data     View larger image The ... limit of detection values. Prior to accessing the TAD Web Application ( https://tad.larc.nasa.gov ) for the first time, users must ...

  13. The airborne laser

    NASA Astrophysics Data System (ADS)

    Lamberson, Steven; Schall, Harold; Shattuck, Paul

    2007-05-01

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

  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. Noise prevention

    NASA Astrophysics Data System (ADS)

    Methods for noise abatement are discussed. Noise nuisance, types of noise (continuous, fluctuating, intermittent, pulsed), and types of noise abatement (absorption, vibration damping, isolation) are defined. Rockwool panels, industrial ceiling panels, baffles, acoustic foam panels, vibration dampers, acoustic mats, sandwich panels, isolating cabins and walls, ear protectors, and curtains are presented.

  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. 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.

  19. 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

  20. Noise pollution: a modem plague.

    PubMed

    Goines, Lisa; Hagler, Louis

    2007-03-01

    Noise is defined as unwanted sound. Environmental noise consists of all the unwanted sounds in our communities except that which originates in the workplace. Environmental noise pollution, a form of air pollution, is a threat to health and well-being. It is more severe and widespread than ever before, and it will continue to increase in magnitude and severity because of population growth, urbanization, and the associated growth in the use of increasingly powerful, varied, and highly mobile sources of noise. It will also continue to grow because of sustained growth in highway, rail, and air traffic, which remain major sources of environmental noise. The potential health effects of noise pollution are numerous, pervasive, persistent, and medically and socially significant. Noise produces direct and cumulative adverse effects that impair health and that degrade residential, social, working, and learning environments with corresponding real (economic) and intangible (well-being) losses. It interferes with sleep, concentration, communication, and recreation. The aim of enlightened governmental controls should be to protect citizens from the adverse effects of airborne pollution, including those produced by noise. People have the right to choose the nature of their acoustical environment; it should not be imposed by others. PMID:17396733

  1. 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.

  2. The Airborne Laser

    NASA Astrophysics Data System (ADS)

    Lamberson, Steven E.

    2002-09-01

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

  3. 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.

  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. 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.

  6. 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 ...

  7. 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 ...

  8. 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.

  9. 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

  10. Airborne antenna pattern calculations

    NASA Technical Reports Server (NTRS)

    Knerr, T. J.; Schaffner, P. R.; Mielke, R. R.; Gilreath, M. C.

    1980-01-01

    A procedure for numerically calculating radiation patterns of fuselage-mounted airborne antennas using the Volumetric Pattern Analysis Program is presented. Special attention is given to aircraft modeling. An actual case study involving a large commercial aircraft is included to illustrate the analysis procedure.

  11. 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)

  12. 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.

  13. Airborne Remote Sensing

    NASA Technical Reports Server (NTRS)

    1992-01-01

    NASA imaging technology has provided the basis for a commercial agricultural reconnaissance service. AG-RECON furnishes information from airborne sensors, aerial photographs and satellite and ground databases to farmers, foresters, geologists, etc. This service produces color "maps" of Earth conditions, which enable clients to detect crop color changes or temperature changes that may indicate fire damage or pest stress problems.

  14. 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.

  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. 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.

  17. Pulsed Doppler lidar airborne scanner

    NASA Astrophysics Data System (ADS)

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

    1985-10-01

    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.

  18. Recent Improvements to the Airborne Visible/Infrared Imaging Spectrometer (AVRIS)

    NASA Technical Reports Server (NTRS)

    Chrien, T.; Eastwood, M.; Green, R.; Sarture, C.

    1995-01-01

    Several improvements have been made to the Airborne Visible/Infrared Imaging Spectrometer (AVRIS) since 1994--new focal plane arrays, a new analog and digital chain and an onboard calibration lamp controlled by radiance feedback. These changes increased the signal-to- noise ratio by 2 to 3 times, eliminated noise spikes and the need for spectral sampling, and greatly reduced dark-current noise.

  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. Propeller tip vortex - A possible contributor to aircraft cabin noise

    NASA Astrophysics Data System (ADS)

    Miller, B. A.; Dittmar, J. H.; Jeracki, R. J.

    1982-01-01

    Wind tunnel model tests support the hypothesis that a propeller tip vortex may subject a downstream wing surface to greater excitation than would be experienced by the aircraft fuselage side wall exposed to propeller-generated noise, ultimately transmitting this structural response to incident dynamic pressure to the cabin interior. Even if structure-borne excitations are less efficient than airborne excitations in the creation of cabin noise, the higher level of the former could still govern cabin noise levels.

  1. Experimental results from an airborne static Fourier transform imaging spectrometer.

    PubMed

    Ferrec, Yann; Taboury, Jean; Sauer, Hervé; Chavel, Pierre; Fournet, Pierre; Coudrain, Christophe; Deschamps, Joël; Primot, Jérôme

    2011-10-20

    A high étendue static Fourier transform spectral imager has been developed for airborne use. This imaging spectrometer, based on a Michelson interferometer with rooftop mirrors, is compact and robust and benefits from a high collection efficiency. Experimental airborne images were acquired in the visible domain. The processing chain to convert raw images to hyperspectral data is described, and airborne spectral images are presented. These experimental results show that the spectral resolution is close to the one expected, but also that the signal to noise ratio is limited by various phenomena (jitter, elevation fluctuations, and one parasitic image). We discuss the origin of those limitations and suggest solutions to circumvent them. PMID:22015418

  2. 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

  3. 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.

  4. 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.

  5. [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

  6. 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.

  7. 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.

  8. 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

  9. Airborne field strength monitoring

    NASA Astrophysics Data System (ADS)

    Bredemeyer, J.; Kleine-Ostmann, T.; Schrader, T.; Münter, K.; Ritter, J.

    2007-06-01

    In civil and military aviation, ground based navigation aids (NAVAIDS) are still crucial for flight guidance even though the acceptance of satellite based systems (GNSS) increases. Part of the calibration process for NAVAIDS (ILS, DME, VOR) is to perform a flight inspection according to specified methods as stated in a document (DOC8071, 2000) by the International Civil Aviation Organization (ICAO). One major task is to determine the coverage, or, in other words, the true signal-in-space field strength of a ground transmitter. This has always been a challenge to flight inspection up to now, since, especially in the L-band (DME, 1GHz), the antenna installed performance was known with an uncertainty of 10 dB or even more. In order to meet ICAO's required accuracy of ±3 dB it is necessary to have a precise 3-D antenna factor of the receiving antenna operating on the airborne platform including all losses and impedance mismatching. Introducing precise, effective antenna factors to flight inspection to achieve the required accuracy is new and not published in relevant papers yet. The authors try to establish a new balanced procedure between simulation and validation by airborne and ground measurements. This involves the interpretation of measured scattering parameters gained both on the ground and airborne in comparison with numerical results obtained by the multilevel fast multipole algorithm (MLFMA) accelerated method of moments (MoM) using a complex geometric model of the aircraft. First results will be presented in this paper.

  10. 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. PMID:7005667

  11. 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.

  12. 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.

  13. Aircraft Noise

    NASA Astrophysics Data System (ADS)

    Michel, Ulf; Dobrzynski, Werner; Splettstoesser, Wolf; Delfs, Jan; Isermann, Ullrich; Obermeier, Frank

    Aircraft industry is exposed to increasing public pressure aiming at a continuing reduction of aircraft noise levels. This is necessary to both compensate for the detrimental effect on noise of the expected increase in air traffic and improve the quality of living in residential areas around airports.

  14. Environmental Noise

    NASA Astrophysics Data System (ADS)

    Rumberg, Martin

    Environmental noise may be defined as unwanted sound that is caused by emissions from traffic (roads, air traffic corridors, and railways), industrial sites and recreational infrastructures, which may cause both annoyance and damage to health. Noise in the environment or community seriously affects people, interfering with daily activities at school, work and home and during leisure time.

  15. 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

  16. 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

  17. 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

  18. 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.

  19. Red Emitting VCSEL

    NASA Astrophysics Data System (ADS)

    Jetter, Michael; Roßbach, Robert; Michler, Peter

    This chapter describes the progress in development of vertical-cavity surface-emitting lasers (VCSEL) emitting in the red spectral region around 650 nm for data transmission over polymer optical fibers (POF). First, growth issues of red VCSEL using two different material systems, namely AlGaAs and AlGaInP, are introduced. In particular, the optical and electrical state-of-the-art characteristics as low threshold currents ({≤} 1 mA) and high output powers (several mW) are presented with a special focus on emission wavelength. Also the thermal budget and heat removal in the devices are pointed out with regard to the geometry of the VCSEL. Small-signal modulation response in terms of maximum resonance frequency in dependance on temperature behavior are discussed. Applications of these devices in optical interconnects are described and digital data transmission at data rates up to 2.1 Gbit/s over step-index POF is reported. These properties make red emitting VCSEL perfectly suited for high-speed low power consuming light sources for optical data communication via POF. By introducing InP quantum dots as gain material in red emitting VCSEL nearly temperature independent record low threshold current densities of around 10 A/cm2 could be observed.

  20. Light-emitting pickles

    NASA Astrophysics Data System (ADS)

    Vollmer, M.; Möllmann, 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.

  1. A 100-micron polarimeter for the Kuiper Airborne Observatory

    SciTech Connect

    Novak, G.; Gonatas, D.P.; Hildebrand, R.H.; Platt, S.R.

    1989-02-01

    Consideration is given to the design and performance of the 100-micron polarimeter proposed for use on the NASA Kuiper Airborne Observatory. The polarimeter specifications are listed. The polarimeter design and data reduction techniques are based on the work of Hildebrand et al. (1984) and Dragovan (1986). The polarimeter has an improved signal-to-noise ratio and systematic measurement errors below 0.2 percent. 20 refs.

  2. A 100-micron polarimeter for the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Novak, G.; Gonatas, D. P.; Hildebrand, R. H.; Platt, S. R.

    1989-01-01

    Consideration is given to the design and performance of the 100-micron polarimeter proposed for use on the NASA Kuiper Airborne Observatory. The polarimeter specifications are listed. The polarimeter design and data reduction techniques are based on the work of Hildebrand et al. (1984) and Dragovan (1986). The polarimeter has an improved signal-to-noise ratio and systematic measurement errors below 0.2 percent.

  3. 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.

  4. 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

  5. Airborne Raman lidar

    NASA Astrophysics Data System (ADS)

    Heaps, Wm. S.; Burris, J.

    1996-12-01

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

  6. 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.

  7. Measurements of Electronic Noise in Gyroklystrons

    NASA Astrophysics Data System (ADS)

    Calame, J. P.

    1999-11-01

    The noise properties of millimeter-wave gyroklystron amplifiers are an important issue in the design of advanced radar and communication systems. Therefore, experimental measurements of electron beam shot noise in a 35 GHz, 225 kW, 30 dB gain, three-cavity gyroklystron have been obtained from both the input and output cavities. This intrinsic noise was initially studied without an applied carrier (i.e. at zero drive power). The noise spectrum emitted by the input cavity has a Lorentzian shape, with peak noise power densities typically reaching 6.3x10-15 W/Hz (-112 dBm/Hz), and typical 3 dB bandwidths of 160 MHz. The output cavity noise spectrum is found to be equal to the input cavity noise spectrum multiplied by the measured linear frequency response of the gyroklystron. The input cavity noise power exhibits complex variations as a function of beam current, beam velocity ratio, and circuit magnetic field. Overall, the measured noise levels at the input cavity are 0 to 5 dB lower than theoretical predictions for shot noise unaltered by collective effects, with the largest reductions occurring at high currents. This implies that space charge has a role in shielding the shot noise. The measurements also fail to show noise growth from electrostatic cyclotron instabilities; analytic theory indicates that the lack of growth is due to the finite velocity spread of the beam and operation at a modest detuning from the cyclotron frequency. Experimental measurements of phase noise in a 4 cavity, 50 dB gain, 35 GHz gyroklystron producing a saturated 200 kW carrier are also under way. Contributions to the phase noise spectrum from shot noise, 1/f noise, and extrinsic noise have been observed.

  8. 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.

  9. 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

  10. 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.

  11. Airborne transmission of lyssaviruses.

    PubMed

    Johnson, N; Phillpotts, R; Fooks, A R

    2006-06-01

    In 2002, a Scottish bat conservationist developed a rabies-like disease and subsequently died. This was caused by infection with European bat lyssavirus 2 (EBLV-2), a virus closely related to Rabies virus (RABV). The source of this infection and the means of transmission have not yet been confirmed. In this study, the hypothesis that lyssaviruses, particularly RABV and the bat variant EBLV-2, might be transmitted via the airborne route was tested. Mice were challenged via direct introduction of lyssavirus into the nasal passages. Two hours after intranasal challenge with a mouse-adapted strain of RABV (Challenge Virus Standard), viral RNA was detectable in the tongue, lungs and stomach. All of the mice challenged by direct intranasal inoculation developed disease signs by 7 days post-infection. Two out of five mice challenged by direct intranasal inoculation of EBLV-2 developed disease between 16 and 19 days post-infection. In addition, a simple apparatus was evaluated in which mice could be exposed experimentally to infectious doses of lyssavirus from an aerosol. Using this approach, mice challenged with RABV, but not those challenged with EBLV-2, were highly susceptible to infection by inhalation. These data support the hypothesis that lyssaviruses, and RABV in particular, can be spread by airborne transmission in a dose-dependent manner. This could present a particular hazard to personnel exposed to aerosols of infectious RABV following accidental release in a laboratory environment. PMID:16687600

  12. 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.

  13. 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.

  14. Mitigation of structureborne noise nuisance

    NASA Astrophysics Data System (ADS)

    Ko, Wing P.

    2005-09-01

    This paper presents a noise complaint case which was solved by me a few years ago in Hong Kong. A newlywed couple in the residential unit complained to the Government that the noise emitted from the pump room directly beneath their unit was very annoying, especially in the night-time period. The owner of the building was then required by the Government to mitigate the noise to the night-time statutory noise requirement within 30 days, otherwise he would be prosecuted. Ideally, the structureborne noise from the pump room could be effectively mitigated by installation of floating slab and vibration isolators under the pumps. Also, the water tanks and water pipes were required to be isolated from the walls and floor. However, this work was impossible to be completed within 30 days to stop the prosecution. Water supply to the above residents would be seriously interrupted during the construction period. As the only noise parameter of the statutory requirement was 30 minute A-weighted Leq, the most effective and practical way in this exigent situation was to reduce the pump operation time within any 30 minute period to decrease the Leq values. In addition, the water pipes and pumps were also required to be isolated from the walls and floor with resilient materials to break the vibration channels. These noise mitigation measures were successfully applied to the pump room before the end of the 30 days. Finally, the noise levels inside the complainant's unit were found to meet the statutory requirement. The noise complaint case was then closed by the Government.

  15. Processor architecture for airborne SAR systems

    NASA Technical Reports Server (NTRS)

    Glass, C. M.

    1983-01-01

    Digital processors for spaceborne imaging radars and application of the technology developed for airborne SAR systems are considered. Transferring algorithms and implementation techniques from airborne to spaceborne SAR processors offers obvious advantages. The following topics are discussed: (1) a quantification of the differences in processing algorithms for airborne and spaceborne SARs; and (2) an overview of three processors for airborne SAR systems.

  16. Evaluation of meteorological airborne Doppler radar

    NASA Technical Reports Server (NTRS)

    Hildebrand, P. H.; Mueller, C. K.

    1984-01-01

    This paper will discuss the capabilities of airborne Doppler radar for atmospheric sciences research. The evaluation is based on airborne and ground based Doppler radar observations of convective storms. The capability of airborne Doppler radar to measure horizontal and vertical air motions is evaluated. Airborne Doppler radar is shown to be a viable tool for atmospheric sciences research.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Instrument description of the airborne microwave temperature profiler

    NASA Technical Reports Server (NTRS)

    Denning, Richard F.; Guidero, Steven L.; Parks, Gary S.; Gary, Bruce L.

    1989-01-01

    The microwave temperature profiler (MTP) is a passive microwave radiometer installed in the NASA ER-2 aircraft and used to measure profiles of air temperature versus altitude. It operates at 57.3 and 58.8 GHz, where oxygen molecules emit thermal radiation. Brightness temperature is measured at a selection of viewing elevation angles every 14 s. MTP was the only remote sensing experiment aboard the ER-2 during the Airborne Antarctic Ozone Experiment. This paper describes hardware, calibration, and performance aspects of the MTP.

  2. 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.

  3. 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

  4. 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.

  5. Thermal infrared spectral imager for airborne science applications

    NASA Astrophysics Data System (ADS)

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

    2009-05-01

    An airborne thermal hyperspectral imager is underdevelopment 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 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 emissivity for various known standard minerals (quartz). A comparison is made using data from the ASTER spectral library.

  6. Towards HyTES: an airborne thermal imaging spectroscopy instrument

    NASA Astrophysics Data System (ADS)

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

    2009-08-01

    An airborne thermal hyperspectral imager is underdevelopment 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 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 emissivity for various known standard minerals (quartz). A comparison is made using data from the ASTER spectral library.

  7. An airborne system for detection of volcanic surface deformations

    NASA Technical Reports Server (NTRS)

    Lunine, J.

    1980-01-01

    A technique is proposed for measuring volcanic deformation on the order of centimeters per day to centimeters per year. An airborne multifrequency pulsed radar, tracking passive ground reflectors spaced at 1 kilometer intervals over a 50 square kilometer area is employed. Identification of targets is accomplished by Doppler and range resolution techniques, with final relative position measurements accomplished by phase comparison of multifrequency signals. Atmospheric path length errors are corrected by an airborne refractometer, meteorological instruments, or other refractive index measuring devices. Anticipated system accuracy is 1-2 cm, with measuring times on the order of minutes. Potential problems exist in the high intrinsic data assimilation rate required of the system to overcome ground backscatter noise.

  8. Airborne rescue system

    NASA Technical Reports Server (NTRS)

    Haslim, Leonard A. (Inventor)

    1991-01-01

    The airborne rescue system includes a boom with telescoping members for extending a line and collar to a rescue victim. The boom extends beyond the tip of the helicopter rotor so that the victim may avoid the rotor downwash. The rescue line is played out and reeled in by winch. The line is temporarily retained under the boom. When the boom is extended, the rescue line passes through clips. When the victim dons the collar and the tension in the line reaches a predetermined level, the clips open and release the line from the boom. Then the rescue line can form a straight line between the victim and the winch, and the victim can be lifted to the helicopter. A translator is utilized to push out or pull in the telescoping members. The translator comprises a tape and a rope. Inside the telescoping members the tape is curled around the rope and the tape has a tube-like configuration. The tape and rope are provided from supply spools.

  9. 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

  10. 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.

  11. 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

  12. Combustion generated noise in gas turbine combustors. [engine noise/noise reduction

    NASA Technical Reports Server (NTRS)

    Strahle, W. C.; Shivashankara, B. N.

    1974-01-01

    Experiments were conducted to determine the noise power and spectra emitted from a gas turbine combustor can exhausting to the atmosphere. Limited hot wire measurements were made of the cold flow turbulence level and spectra within the can. The fuels used were JP-4, acetone and methyl alcohol burning with air at atmospheric pressure. The experimental results show that for a fixed fuel the noise output is dominated by the airflow rate and not the fuel/air ratio. The spectra are dominated by the spectra of the cold flow turbulence spectra which were invariant with airflow rate in the experiments. The effect of fuel type on the noise power output was primarily through the heat of combustion and not the reactivity. A theory of combustion noise based upon the flame radiating to open surroundings is able to reasonably explain the observed results. A thermoacoustic efficiency for noise radiation as high as .00003 was observed in this program for JP-4 fuel. Scaling rules are presented for installed configurations.

  13. 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)

  14. Atmospheric Emitted Radiance Interferometer

    DOE Data Explorer

    Gero, Jonathan; Ermold, Brian; Gaustad, Krista; Koontz, Annette; Hackel, Denny; Garcia, Raymond

    2005-01-01

    The atmospheric emitted radiance interferometer (AERI) is a ground-based instrument that measures the downwelling infrared radiance from the Earth’s atmosphere. The observations have broad spectral content and sufficient spectral resolution to discriminate among gaseous emitters (e.g., carbon dioxide and water vapor) and suspended matter (e.g., aerosols, water droplets, and ice crystals). These upward-looking surface observations can be used to obtain vertical profiles of tropospheric temperature and water vapor, as well as measurements of trace gases (e.g., ozone, carbon monoxide, and methane) and downwelling infrared spectral signatures of clouds and aerosols. The AERI is a passive remote sounding instrument, employing a Fourier transform spectrometer operating in the spectral range 3.3–19.2 μm (520–3020 cm-1) at an unapodized resolution of 0.5 cm-1 (max optical path difference of 1 cm). The extended-range AERI (ER-AERI) deployed in dry climates, like in Alaska, have a spectral range of 3.3–25.0 μm (400–3020 cm-1) that allow measurements in the far-infrared region. Typically, the AERI averages views of the sky over a 16-second interval and operates continuously.

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. Aircraft noise problems

    NASA Astrophysics Data System (ADS)

    1981-01-01

    The problems related to aircraft noise were studied. Physical origin (sound), human reaction (noise), quantization of noise and sound sources of aircraft noise are discussed. Noise abatement at the source, technical, fleet-political and air traffic measures are explained. The measurements and future developments are also discussed. The position of Lufthansa as regards aircraft noise problems is depicted.

  1. 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.

  2. Noise Abatement

    NASA Technical Reports Server (NTRS)

    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.

  3. 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

  4. 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.

  5. Ultrasonic airborne insertion loss measurements at normal incidence (L).

    PubMed

    Farley, Jayrin; Anderson, Brian E

    2010-12-01

    Transmission loss and insertion loss measurements of building materials at audible frequencies are commonly made using plane wave tubes or as a panel between reverberant rooms. These measurements provide information for noise isolation control in architectural acoustics and in product development. Airborne ultrasonic sound transmission through common building materials has not been fully explored. Technologies and products that utilize ultrasonic frequencies are becoming increasingly more common, hence the need to conduct such measurements. This letter presents preliminary measurements of the ultrasonic insertion loss levels for common building materials over a frequency range of 28-90 kHz using continuous-wave excitation. PMID:21218864

  6. 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.

  7. 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.

  8. 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...

  9. 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.

  10. 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

  11. 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 ...

  12. Decomposition of noise sources of synchronous belt drives

    NASA Astrophysics Data System (ADS)

    Chen, Gang (Sheng); Zheng, Hui; Qatu, Mohamad

    2013-04-01

    In this paper, the noise sources of synchronous belt are decomposed and formulated based on the analysis of the impact dynamics of belt-sprocket tooth interface. The impact/contact of belt-sprocket tooth and the vibration of belt span are modeled. The friction-vibrations interaction of belt tooth and the airflow-induced acoustic wave during belt-sprocket tooth engagement are comprehensively formulated. The structure-borne noise consists of structural impact noise and friction-induced noise. The airborne noise is due to airflow-induced acoustic wave during belt-sprocket tooth engaging. The spectral signatures of the varied noise are quantified, and the case studies are given to illustrate the influences of the tooth parameters and operation conditions on noise. The noise due to belt span vibration under impact ranges from hundreds to several thousand Hz. The impact noise, friction-induced noise and airflow-induced noise of belt tooth ranges from 3 kHz to 10 kHz.

  13. 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

  14. 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.

  15. Aircraft measurement of radio frequency noise at 121.5 MHz, 243MHz and 406MHz

    NASA Technical Reports Server (NTRS)

    Taylor, R. E.; Hill, J. S.

    1977-01-01

    An airborne survey measurement of terrestrial radio-frequency noise over U.S. metropolitan areas has been made at 121.5, 243 and 406 MHz with horizontal-polarization monopole antennas. Flights were at 25,000 feet altitude during the period from December 30, 1976 to January 8, 1977. Radio-noise measurements, expressed in equivalent antenna-noise temperature, indicate a steady-background noise temperature of 572,000 K, at 121.5 MHz, during daylight over New York City. This data is helpful in compiling radio-noise temperature maps; in turn useful for designing satellite-aided, emergency-distress search and rescue communication systems.

  16. Experimental investigations on airborne gravimetry based on compressed sensing.

    PubMed

    Yang, Yapeng; Wu, Meiping; Wang, Jinling; Zhang, Kaidong; Cao, Juliang; Cai, Shaokun

    2014-01-01

    Gravity surveys are an important research topic in geophysics and geodynamics. This paper investigates a method for high accuracy large scale gravity anomaly data reconstruction. Based on the airborne gravimetry technology, a flight test was carried out in China with the strap-down airborne gravimeter (SGA-WZ) developed by the Laboratory of Inertial Technology of the National University of Defense Technology. Taking into account the sparsity of airborne gravimetry by the discrete Fourier transform (DFT), this paper proposes a method for gravity anomaly data reconstruction using the theory of compressed sensing (CS). The gravity anomaly data reconstruction is an ill-posed inverse problem, which can be transformed into a sparse optimization problem. This paper uses the zero-norm as the objective function and presents a greedy algorithm called Orthogonal Matching Pursuit (OMP) to solve the corresponding minimization problem. The test results have revealed that the compressed sampling rate is approximately 14%, the standard deviation of the reconstruction error by OMP is 0.03 mGal and the signal-to-noise ratio (SNR) is 56.48 dB. In contrast, the standard deviation of the reconstruction error by the existing nearest-interpolation method (NIPM) is 0.15 mGal and the SNR is 42.29 dB. These results have shown that the OMP algorithm can reconstruct the gravity anomaly data with higher accuracy and fewer measurements. PMID:24647125

  17. Monitoring human and vehicle activities using airborne video

    NASA Astrophysics Data System (ADS)

    Cutler, Ross; Shekhar, Chandra S.; Burns, B.; Chellappa, Rama; Bolles, Robert C.; Davis, Larry S.

    2000-05-01

    Ongoing work in Activity Monitoring (AM) for the Airborne Video Surveillance (AVS) project is described. The goal for AM is to recognize activities of interest involving humans and vehicles using airborne video. AM consists of three major components: (1) moving object detection, tracking, and classification; (2) image to site-model registration; (3) activity recognition. Detecting and tracking humans and vehicles form airborne video is a challenging problem due to image noise, low GSD, poor contrast, motion parallax, motion blur, and camera blur, and camera jitter. We use frame-to- frame affine-warping stabilization and temporally integrated intensity differences to detect independent motion. Moving objects are initially tracked using nearest-neighbor correspondence, followed by a greedy method that favors long track lengths and assumes locally constant velocity. Object classification is based on object size, velocity, and periodicity of motion. Site-model registration uses GPS information and camera/airplane orientations to provide an initial geolocation with +/- 100m accuracy at an elevation of 1000m. A semi-automatic procedure is utilized to improve the accuracy to +/- 5m. The activity recognition component uses the geolocated tracked objects and the site-model to detect pre-specified activities, such as people entering a forbidden area and a group of vehicles leaving a staging area.

  18. Three years of practical use of airborne gravity gradiometry

    NASA Astrophysics Data System (ADS)

    van Leeuwen, E.

    2003-04-01

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

  19. Experimental Investigations on Airborne Gravimetry Based on Compressed Sensing

    PubMed Central

    Yang, Yapeng; Wu, Meiping; Wang, Jinling; Zhang, Kaidong; Cao, Juliang; Cai, Shaokun

    2014-01-01

    Gravity surveys are an important research topic in geophysics and geodynamics. This paper investigates a method for high accuracy large scale gravity anomaly data reconstruction. Based on the airborne gravimetry technology, a flight test was carried out in China with the strap-down airborne gravimeter (SGA-WZ) developed by the Laboratory of Inertial Technology of the National University of Defense Technology. Taking into account the sparsity of airborne gravimetry by the discrete Fourier transform (DFT), this paper proposes a method for gravity anomaly data reconstruction using the theory of compressed sensing (CS). The gravity anomaly data reconstruction is an ill-posed inverse problem, which can be transformed into a sparse optimization problem. This paper uses the zero-norm as the objective function and presents a greedy algorithm called Orthogonal Matching Pursuit (OMP) to solve the corresponding minimization problem. The test results have revealed that the compressed sampling rate is approximately 14%, the standard deviation of the reconstruction error by OMP is 0.03 mGal and the signal-to-noise ratio (SNR) is 56.48 dB. In contrast, the standard deviation of the reconstruction error by the existing nearest-interpolation method (NIPM) is 0.15 mGal and the SNR is 42.29 dB. These results have shown that the OMP algorithm can reconstruct the gravity anomaly data with higher accuracy and fewer measurements. PMID:24647125

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. AARD - Autonomous Airborne Refueling Demonstration

    NASA Technical Reports Server (NTRS)

    Ewers, Dick

    2007-01-01

    This viewgraph document reviews the Autonomous Airborne Refueling Demonstration program, and NASA Dryden's work in the program. The primary goal of the program is to make one fully automatic probe-to-drogue engagement using the AARD system. There are pictures of the aircraft approaching to the docking.

  5. 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.

  6. 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

  7. Helicopter engine core noise

    NASA Astrophysics Data System (ADS)

    Vonglahn, U. H.

    1982-07-01

    Calculated engine core noise levels, based on NASA Lewis prediction procedures, for five representative helicopter engines are compared with measured total helicopter noise levels and ICAO helicopter noise certification requirements. Comparisons are made for level flyover and approach procedures. The measured noise levels are generally significantly greater than those predicted for the core noise levels, except for the Sikorsky S-61 and S-64 helicopters. However, the predicted engine core noise levels are generally at or within 3 dB of the ICAO noise rules. Consequently, helicopter engine core noise can be a significant contributor to the overall helicopter noise signature.

  8. Helicopter engine core noise

    NASA Technical Reports Server (NTRS)

    Vonglahn, U. H.

    1982-01-01

    Calculated engine core noise levels, based on NASA Lewis prediction procedures, for five representative helicopter engines are compared with measured total helicopter noise levels and ICAO helicopter noise certification requirements. Comparisons are made for level flyover and approach procedures. The measured noise levels are generally significantly greater than those predicted for the core noise levels, except for the Sikorsky S-61 and S-64 helicopters. However, the predicted engine core noise levels are generally at or within 3 dB of the ICAO noise rules. Consequently, helicopter engine core noise can be a significant contributor to the overall helicopter noise signature.

  9. 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.

  10. 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

  11. Turbomachinery noise

    NASA Technical Reports Server (NTRS)

    Groeneweg, John F.; Sofrin, Thomas G.; Rice, Edward J.; Gliebe, Phillip R.

    1991-01-01

    Summarized here are key advances in experimental techniques and theoretical applications which point the way to a broad understanding and control of turbomachinery noise. On the experimental side, the development of effective inflow control techniques makes it possible to conduct, in ground based facilities, definitive experiments in internally controlled blade row interactions. Results can now be valid indicators of flight behavior and can provide a firm base for comparison with analytical results. Inflow control coupled with detailed diagnostic tools such as blade pressure measurements can be used to uncover the more subtle mechanisms such as rotor strut interaction, which can set tone levels for some engine configurations. Initial mappings of rotor wake-vortex flow fields have provided a data base for a first generation semiempirical flow disturbance model. Laser velocimetry offers a nonintrusive method for validating and improving the model. Digital data systems and signal processing algorithms are bringing mode measurement closer to a working tool that can be frequently applied to a real machine such as a turbofan engine. On the analytical side, models of most of the links in the chain from turbomachine blade source to far field observation point have been formulated. Three dimensional lifting surface theory for blade rows, including source noncompactness and cascade effects, blade row transmission models incorporating mode and frequency scattering, and modal radiation calculations, including hybrid numerical-analytical approaches, are tools which await further application.

  12. 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

  13. 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.

  14. UHB demonstrator interior noise control flight tests and analysis

    NASA Astrophysics Data System (ADS)

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

    1989-10-01

    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.

  15. Satellite and airborne IR sensor validation by an airborne interferometer

    SciTech Connect

    Gumley, L.E.; Delst, P.F. van; Moeller, C.C.

    1996-11-01

    The validation of in-orbit longwave IR radiances from the GOES-8 Sounder and inflight longwave IR radiances from the MODIS Airborne Simulator (MAS) is described. The reference used is the airborne University of Wisconsin High Resolution Interferometer Sounder (HIS). The calibration of each sensor is described. Data collected during the Ocean Temperature Interferometric Survey (OTIS) experiment in January 1995 is used in the comparison between sensors. Detailed forward calculations of at-sensor radiance are used to account for the difference in GOES-8 and HIS altitude and viewing geometry. MAS radiances and spectrally averaged HIS radiances are compared directly. Differences between GOES-8 and HIS brightness temperatures, and GOES-8 and MAS brightness temperatures, are found to be with 1.0 K for the majority of longwave channels examined. The same validation approach will be used for future sensors such as the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Atmospheric Infrared Sounder (AIRS). 11 refs., 2 figs., 4 tabs.

  16. NOISE-CON 90; Proceedings of the 10th National Conference on Noise Control Engineering, University of Texas, Austin, Oct. 15-17, 1990

    NASA Astrophysics Data System (ADS)

    Busch-Vishniac, Ilene J.

    Topics presented include a test fixture for measuring small fan vibration, the statistical energy analysis of a geared rotor system, helicopter far-field acoustic levels as a function of reduced rotor speeds, and the stability of active noise control systems in ducts. Also presented are active control of the force response of a finite beam, the selection of noise monitoring sites for Logan airport and Hanscom field, aircraft noise and the elderly, and the development of multiple-input models for airborne noise prediction.

  17. Propeller-induced structure-borne noise - Laboratory-based test apparatus

    NASA Technical Reports Server (NTRS)

    Unruh, J. F.

    1986-01-01

    A potentially important source of structure-borne interior noise transmission in advanced turboprop aircraft is the impingement of the propeller wake/vortex on downstream aerodynamic surfaces. The expected levels of propeller wake/vortex-induced structure-borne noise transmission are not known nor can they be determined with present-day technology. A test apparatus has been designed, built and calibrated for the purposes of studying propeller-induced, structure-borne noise transmission in prototypical aircraft structures. The principal approach to the test apparatus design was to provide a physical means of separating the airborne and structure-borne noise components so that the structure-borne noise transmission response could be studied directly without airborne noise contamination. This was accomplished by housing the receiving fuselage structure in an acoustic shield fitted with a wing-to-fuselage acoustic seal. Initial evaluation of the wing-to-fuselage acoustic seal indicates adequate airborne noise isolation to allow direct study of structure-borne noise transmission.

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

    PubMed

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

    2007-10-17

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

  20. Measurements of intrinsic shot noise in a 35 GHz gyroklystron

    NASA Astrophysics Data System (ADS)

    Calame, J. P.; Danly, B. G.; Garven, M.

    1999-07-01

    Experimental measurements of electron beam shot noise in a 35 GHz, 225 kW, three-cavity gyroklystron have been obtained from both the input and output cavities. This intrinsic noise was studied in the absence of an applied carrier (i.e., at zero drive power). The spectrum of the noise emitted by the input cavity is found to have a Lorentzian shape, with peak noise power densities from the input cavity typically reaching 6.3×10-15 W/Hz (-112 dBm/Hz), and typical 3 dB bandwidths of 160 MHz. The output cavity noise spectrum is found to be equal to the input cavity noise spectrum multiplied by the measured linear frequency response of the gyroklystron. The measured noise levels at the input cavity are 0-5 dB lower than theoretical predictions for shot noise unaltered by collective effects. Furthermore, the input cavity noise power exhibits complex variations as a function of beam current, beam velocity ratio, and circuit magnetic field that are not predicted by present theory. Noise-to-carrier ratios expected in the input cavity during full power amplifier operation are inferred from the noise measurements and known values of drive power required to saturate the gyroklystron. The noise-to-carrier ratio, with typical values of -90 to -80 dBc, is found to be a strong function of the operating parameters.

  1. 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.

  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. 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.

  4. Minimal noise subsystems

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoting; Byrd, Mark; Jacobs, Kurt

    2016-03-01

    A system subjected to noise contains a decoherence-free subspace or subsystem (DFS) only if the noise possesses an exact symmetry. Here we consider noise models in which a perturbation breaks a symmetry of the noise, so that if S is a DFS under a given noise process it is no longer so under the new perturbed noise process. We ask whether there is a subspace or subsystem that is more robust to the perturbed noise than S . To answer this question we develop a numerical method that allows us to search for subspaces or subsystems that are maximally robust to arbitrary noise processes. We apply this method to a number of examples, and find that a subsystem that is a DFS is often not the subsystem that experiences minimal noise when the symmetry of the noise is broken by a perturbation. We discuss which classes of noise have this property.

  5. Airborne microorganisms from waste containers.

    PubMed

    Jedlicka, Sabrina S; Stravitz, David M; Lyman, Charles E

    2012-01-01

    In physician's offices and biomedical labs, biological waste is handled every day. This waste is disposed of in waste containers designed for holding red autoclave bags. The containers used in these environments are closed hands-free containers, often with a step pedal. While these containers protect the user from surface-borne microorganisms, the containers may allow airborne microorganisms to escape via the open/close mechanism because of the air current produced upon open/close cycles. In this study, the air current was shown to be sufficient to allow airborne escape of microorganisms held in the container, including Aspergillus niger. However, bacterial cultures, such as Escherichia coli and Lactococcus lactis did not escape. This may be due to the choice of bacterial cultures and the absence of solid waste, such as dust or other particulate matter in the waste containers, that such strains of bacteria could travel on during aerosolization. We compared these results to those obtained using a re-designed receptacle, which mimimizes air currents, and detected no escaping microorganisms. This study highlights one potential source of airborne contamination in labs, hospitals, and other environments that dispose of biological waste. PMID:23047084

  6. Airborne lidar global positioning investigations

    NASA Technical Reports Server (NTRS)

    Krabill, W. B.

    1988-01-01

    The Global Positioning System (GPS) network of satellites shows high promise of revolutionizing methods for conducting surveying, navigation, and positioning. This is especially true in the case of airborne or satellite positioning. A single GPS receiver (suitably adapted for aircraft deployment) can yield positioning accuracies (world-wide) in the order of 30 to 50 m vertically, as well as horizontally. This accuracy is dramatically improved when a second GPS receiver is positioned at a known horizontal and vertical reference. Absolute horizontal and vertical positioning of 1 to 2 m are easily achieved over areas of separation of tens of km. If four common satellites remain in lock in both receivers, then differential phase pseudo-ranges on the GPS L-band carrier can be utilized to achieve accuracies of + or - 10 cm and perhaps as good as + or - 2 cm. The initial proof of concept investigation for airborne positioning using the phase difference between the airborne and stationary GPS receivers was conducted and is examined.

  7. 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.

  8. 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.

  9. 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

  10. Forced-air warming: a source of airborne contamination in the operating room?

    PubMed Central

    Albrecht, Mark; Gauthier, Robert; Leaper, David

    2009-01-01

    Forced-air-warming (FAW) is an effective and widely used means for maintaining surgical normothermia, but FAW also has the potential to generate and mobilize airborne contamination in the operating room. We measured the emission of viable and non-viable forms of airborne contamination from an arbitrary selection of FAW blowers (n=25) in the operating room. A laser particle counter measured particulate concentrations of the air near the intake filter and in the distal hose airstream. Filtration efficiency was calculated as the reduction in particulate concentration in the distal hose airstream relative to that of the intake. Microbial colonization of the FAW blower's internal hose surfaces was assessed by culturing the microorganisms recovered through swabbing (n=17) and rinsing (n=9) techniques. Particle counting revealed that 24% of FAW blowers were emitting significant levels of internally generated airborne contamination in the 0.5 to 5.0 µm size range, evidenced by a steep decrease in FAW blower filtration efficiency for particles 0.5 to 5.0 µm in size. The particle size-range-specific reduction in efficiency could not be explained by the filtration properties of the intake filter. Instead, the reduction was found to be caused by size-range-specific particle generation within the FAW blowers. Microorganisms were detected on the internal air path surfaces of 94% of FAW blowers. The design of FAW blowers was found to be questionable for preventing the build-up of internal contamination and the emission of airborne contamination into the operating room. Although we did not evaluate the link between FAW and surgical site infection rates, a significant percentage of FAW blowers with positive microbial cultures were emitting internally generated airborne contamination within the size range of free floating bacteria and fungi (<4 µm) that could, conceivably, settle onto the surgical site. PMID:21808690

  11. Survival rate of airborne Mycobacterium bovis.

    PubMed

    Gannon, B W; Hayes, C M; Roe, J M

    2007-04-01

    Despite years of study the principle transmission route of bovine tuberculosis to cattle remains unresolved. The distribution of pathological lesions, which are concentrated in the respiratory system, and the very low dose of Mycobacterium bovis needed to initiate infection from a respiratory tract challenge suggest that the disease is spread by airborne transmission. Critical to the airborne transmission of a pathogenic microorganism is its ability to survive the stresses incurred whilst airborne. This study demonstrates that M. bovis is resistant to the stresses imposed immediately after becoming airborne, 94% surviving the first 10 min after aerosolisation. Once airborne the organism is robust, its viability decreasing with a half-life of approximately 1.5 hours. These findings support the hypothesis that airborne transmission is the principle route of infection for bovine tuberculosis. PMID:17045316

  12. 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.

  13. 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.

  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, 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.

  16. 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.

  17. 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…

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. High sensitive airborne radioiodine monitor.

    PubMed

    Ogata, Yoshimune; Yamasaki, Tadashi; Hanafusa, Ryuji

    2013-11-01

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

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. Modeling Airborne Gravity Data with Local Functions for Regional Geoid Enhancement ---- A Case Study in Puerto Rico Area

    NASA Astrophysics Data System (ADS)

    Li, Xiaopeng

    2016-04-01

    Airborne gravimetry has been used as the primary method to quickly and economically obtain updated gravity field information over a region, targeted specifically. Thus, unlike the satellite missions that provide global or near global data coverage, the observables from airborne campaigns are apparently space limited. Moreover, they are also band limited in the frequency domain, considering that various filter banks and/or de-noising techniques have to be applied to overcome the low signal to noise ratio problem that are presented in the airborne systems due to mechanical and mathematical limitations in computing the accelerations, both the kinematic one and the dynamic one. As a result, in this study, a band-limited local function system based on the point mass model is used to process these airborne gravity data that have both a limited frequency domain and a limited space domain in the target area: Puerto Rico Island and its nearby ocean areas. The resulting geoid model show obvious middle to short wavelength geoid changes due to airborne gravity data contribution. In the land area, these changes improved the geoid precision from 3.27cm to 2.09cm at the local GNSS/Leveling bench marks. More importantly, the error trend in the geoid models is largely reduced if not completely removed. Various oceanographic models will be used to validate the geoid changes in the nearby open sea areas.

  14. 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.

  15. Shanghai alleviates noise pollution

    SciTech Connect

    Ding Runling

    1983-07-14

    ''Environmental noise is now under control in Shanghai, the level of environmental noise is basically holding steady, and in some areas industrial and traffic noise has decreased.'' These were the conclusions of research by Hong Zonghui (3163 1350 6540) and Wang Shixian (3769 6164 6343) of Tongji University's Acoustics Laboratory, as put forward at a recent public academic lecture at Tongji University. In order to eliminate noise from the environment, Tongji University in the early 1970's began conducting investigations and research on noise pollution and its control together with concerned units in this city. After tests in a network of 2,117 points throughout the city, they determined that the most common form of noise pollution is traffic, which accounts for 50 percent of all noise. Since 1979, this city has adopted successive measures in the area of traffic control in order to eliminate the source of noise. Traffic noise has now dropped about 3 decibels in the city. This research report also pointed out that according to the results of regional environmental noise tests, this city does not meet the noise pollution standards set by the state. Tugboats on the Suzhou He blow their whistles late at night, and the noise at riverside homes can reach 82 decibels; the Fangua Lane residential district is close to a railroad where engine noise can reach 89 decibels and affect the residents' health. In addition, rather serious noise pollution is produced by more than 300 handicraft, light industry, textile, and electrical machinery plants.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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…

  2. 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.

  3. 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.

  4. 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.

  5. 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.

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

    PubMed

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

    2015-11-01

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

  7. On Observer Internal Noise

    NASA Astrophysics Data System (ADS)

    Burgess, Arthur E.

    1986-06-01

    Human observers behave as if they have two sources of intrinsic variability, commonly referred to as internal noise. One component (here referred to as "constant") is independent of the external noise level but does depend on mean display luminance. The other component (referred to as "induced") is directly proportional to the external noise level and dominates when the display noise is easily visible. The induced internal noise is predicted by two models - one based on intrinsic signal parameter jitter and the other on a zone of indecision. Spectral density is the appropriate measure for internal noise.

  8. Continuous miner noise

    SciTech Connect

    Robertson, J.

    1981-08-01

    Noise generated by continuous miners in underground coal production is an important health hazard. Laboratory tests of simulated cutting operations and in-mine noise measurements have been made. These show that coal cutting noise and conveyor noise are the dominant sources of miner operational noise. Typical noise levels for cutting and conveying operations are 97 dBA. For full operation of all machine systems, the overall sound pressure level is approximately 101 dBA. In-mine and laboratory test results show excellent agreement in both A-weighted overall levels as well as A-weighted one-third octave band spectra.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Predicting Aircraft Noise Levels

    NASA Technical Reports Server (NTRS)

    Clark, B. J.

    1983-01-01

    Computer program developed for predicting aircraft noise levels either in flight or in ground tests. Noise sources include fan inlet and exhaust jet flap (for powered lift), core (combustor), turbine and airframe. Program written in FORTRAN IV.

  18. NASA propeller noise research

    NASA Technical Reports Server (NTRS)

    Greene, G. C.

    1980-01-01

    The research in propeller noise prediction, noise/performance optimization, and interior reduction is described. Selected results are presented to illustrate the status of the technology and the direction of future research.

  19. 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)

  20. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2002-09-01

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

  2. Interspecific bacterial sensing through airborne signals modulates locomotion and drug resistance.

    PubMed

    Kim, Kwang-sun; Lee, Soohyun; Ryu, Choong-Min

    2013-01-01

    Bacteria use chemical signals to sense each other and to regulate various physiological functions. Although it is known that some airborne volatile organic compounds function as bacterial signalling molecules, their identities and effects on global gene expression and bacterial physiological processes remain largely unknown. Here we perform microarray analyses of Escherichia coli exposed to volatile organic compounds emitted from Bacillus subtilis. We find that 2,3-butanedione and glyoxylic acid mediate global changes in gene expression related to motility and antibiotic resistance. Volatile organic compound-dependent phenotypes are conserved among bacteria and are regulated by the previously uncharacterized ypdB gene product through the downstream transcription factors soxS, rpoS or yjhU. These results strongly suggest that bacteria use airborne volatile organic compounds to sense other bacteria and to change master regulatory gene activity to adapt. PMID:23651997

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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 ...

  8. 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.

  9. Dragline noise survey

    NASA Astrophysics Data System (ADS)

    Vipperman, Jeffrey S.; Bauer, Eric R.

    2002-05-01

    It is estimated that 70%-90% of miners have enough noise induced hearing loss (NIHL) to be classified as a disability (NIOSH, Publication No. 76-172, 1976; Franks, NIOSH Internal Report, 1996). In response, NIOSH is conducting a cross-sectional survey of the mining industry in order to determine the sources of mining noise and offer recommendations on how to mitigate high noise levels, and bring mining operations into compliance with the recent mining noise regulation: 30CFR, Part 62. This paper will outline the results from noise surveys of eight draglines which operate in above-ground coal mining operations. The data recorded include noise dosimetry in conjunction with time-at-task studies and 1/3-octave sound level (Leq, Lmin, and Lmax) measurements. The 1/3-octave band readings were used to create noise contour maps which allowed the spatial and frequency information of the noise to be considered. Comparison of Lmin and Lmax levels offer insight into the variability of the noise levels inside the dragline. The potential for administrative controls is limited due to consistently high noise levels throughout the deck. Implementation of engineering controls is also hindered by the size and number of the noise sources and the frequency content of the noise.

  10. 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.

  11. The Problem of "Noise"

    ERIC Educational Resources Information Center

    Vagianos, Louis

    1972-01-01

    The library problem consists of equal parts of external and internal noise. The external noise consists of the volume of publication. The internal noise can be characterized by the present and continuing brouhaha concerning reform of library education. Scientists frankly regard librarians as impediments to information. (Author/NH)

  12. 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.

  13. 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.

  14. 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

  15. 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).

  16. Classical noise, quantum noise and secure communication

    NASA Astrophysics Data System (ADS)

    Tannous, C.; Langlois, J.

    2016-01-01

    Secure communication based on message encryption might be performed by combining the message with controlled noise (called pseudo-noise) as performed in spread-spectrum communication used presently in Wi-Fi and smartphone telecommunication systems. Quantum communication based on entanglement is another route for securing communications as demonstrated by several important experiments described in this work. The central role played by the photon in unifying the description of classical and quantum noise as major ingredients of secure communication systems is highlighted and described on the basis of the classical and quantum fluctuation dissipation theorems.

  17. 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.

  18. Airborne imaging spectrometer development tasks

    NASA Astrophysics Data System (ADS)

    Bolten, John

    The tasks that must be completed to design and build an airborne imaging spectrometer are listed. The manpower and resources required to do these tasks must be estimated by the people responsible for that work. The tasks are broken down by instrument subsystem or discipline. The instrument performance can be assessed at various stages during the development. The initial assessment should be done with the preliminary computer model. The instrument calibration facilities should be designed, but no calibration facilities are needed. The intermediate assessment can be done when the front end has been assembled. The preliminary instrument calibration facility should be available at this stage. The final assessment can only be done when the instrument is complete and ready for flight. For this, the final instrument calibration facility and the flight qualification facilities must be ready. The final assessment is discussed in each discipline under the section on integration and test.

  19. Research on MLS airborne antenna

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

    Numerical solutions for the radiation patterns of antennas mounted on aircraft are developed. The airborne antenna problems associated with the Microwave Landing System (MLS) are emphasized. Based on the requirements of the MLS, volumetric pattern solutions are essential. Previous attempts at solving for the volumetric patterns were found to be far too complex and very inefficient. However as a result of previous efforts, it is possible to combine the elevation and roll plane pattern solutions to give the complete volumetric pattern. This combination is described as well as the aircraft simulation models used in the analysis. A numerical technique is presented to aid in the simulation of the aircraft studied. Finally, a description of the input data used in the computer code is given.

  20. 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. PMID:23962732

  1. Airborne remote sensing of forest biomes

    NASA Technical Reports Server (NTRS)

    Sader, Steven A.

    1987-01-01

    Airborne sensor data of forest biomes obtained using an SAR, a laser profiler, an IR MSS, and a TM simulator are presented and examined. The SAR was utilized to investigate forest canopy structures in Mississippi and Costa Rica; the IR MSS measured forest canopy temperatures in Oregon and Puerto Rico; the TM simulator was employed in a tropical forest in Puerto Rico; and the laser profiler studied forest canopy characteristics in Costa Rica. The advantages and disadvantages of airborne systems are discussed. It is noted that the airborne sensors provide measurements applicable to forest monitoring programs.

  2. Combustion and core noise

    NASA Astrophysics Data System (ADS)

    Mahan, J. Robert; Karchmer, Allen

    1991-08-01

    Two types of aircraft power plant are considered: the gas turbine and the reciprocating engine. The engine types considered are: the reciprocating engine, the turbojet engine, the turboprop engine, and the turbofan engine. Combustion noise in gas turbine engines is discussed, and reciprocating-engine combustion noise is also briefly described. The following subject areas are covered: configuration variables, operational variables, characteristics of combustion and core noise, sources of combustion noise, combustion noise theory and comparison with experiment, available prediction methods, diagnostic techniques, measurement techniques, data interpretation, and example applications.

  3. 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.

  4. 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.

  5. 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.

  6. Acoustical measurement separates core noise and jet noise

    NASA Technical Reports Server (NTRS)

    Parthasarathy, S. P.

    1980-01-01

    Measuring technique discriminates between jet noise and core noise of jet engine. Results of experimentation confirmed that core noise and jet noise can be separated by examining cross-correlation of far-field microphone signals and that crossover point between core noise and jet noise moves toward higher velocities at higher angles with respect to jet axis.

  7. 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.

  8. 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.

  9. Low frequency cultural noise

    NASA Astrophysics Data System (ADS)

    Sheen, Dong-Hoon; Shin, Jin Soo; Kang, Tae-Seob; Baag, Chang-Eob

    2009-09-01

    Abnormal cultural seismic noise is observed in the frequency range of 0.01-0.05 Hz. Cultural noise generated by human activities is generally observed in frequencies above 1 Hz, and is greater in the daytime than at night. The low-frequency noise presented in this paper exhibits a characteristic amplitude variation and can be easily identified from time domain seismograms in the frequency range of interest. The amplitude variation is predominantly in the vertical component, but the horizontal components also show variations. Low-frequency noise is markedly periodic, which reinforces its interpretation as cultural noise. Such noise is observed world-wide, but is limited to areas in the vicinity of railways. The amplitude variation in seismograms correlates strongly with railway timetables, and the waveform shows a wavelength shift associated with the Doppler effect, which indicates that the origin of seismic background noise in the frequency range 0.01-0.05 Hz is railways.

  10. Continuous miner noise

    SciTech Connect

    Robertson, J.; Kovac, J.; Bartholomae, R.

    1981-08-01

    Noise generated by continuous miners in underground coal production is an important health hazard. Bureau of Mines contract J0387229 charters investigation and control of this noise through laboratory tests of simulated cutting operations and through in-mine noise measurements. The results of these investigations indicate that coal cutting noise and conveyor noise are dominant sources of miner operational noise. Typical noise levels for both cutting and conveying operations are approximately 97 dBA. For full operation of all machine systems, the overall sound pressure level is approximately 101 dBA. In-mine and laboratory test results show agreement in both A-weighted overall levels as well as A-weighted one-third octave band spectra. 4 refs.

  11. 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

  12. Validation of Airborne CO2 Laser Measurements

    NASA Astrophysics Data System (ADS)

    Browell, E. V.; Dobler, J. T.; Kooi, S.; Fenn, M. A.; Choi, Y.; Vay, S. A.; Harrison, F. W.; Moore, B.; Zaccheo, T. S.

    2010-12-01

    This paper discusses the flight test validation of a unique, multi-frequency, intensity-modulated, single-beam laser absorption spectrometer (LAS) that operates near 1.57 μm for remote column CO2 measurements. This laser system is under development for a future space-based mission to determine the global distribution of regional-scale CO2 sources and sinks, which is the objective of the NASA Active Sensing of CO2 Emissions during Nights, Days, and Seasons (ASCENDS) mission. A prototype of this LAS system, called the Multi-frequency Fiber Laser Lidar (MFLL), was developed by ITT, and it has been flight tested in nine airborne campaigns since May 2005. This paper focuses on the most recent results obtained over the last two years of flight-testing where the MFLL remote CO2 column measurements were evaluated against airborne in situ CO2 profile measurements traceable to World Meteorological Organization standards. A comprehensive multiple-aircraft flight test program was conducted over Oklahoma and Virginia in July-August 2009. The MFLL obtained surface reflectance and average CO2 column variations along the 50-km flight legs over the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Central Facility (CF) in Lamont, Oklahoma; over rural Virginia and North Carolina; and over the Chesapeake Bay. For a flight altitude of 4.6 km, the average signal to noise ratio (SNR) for a 1-s CO2 column measurement was found to be 760, which is the equivalent of a CO2 mixing ratio precision of 0.60 ppmv, and for a 10-s average the SNR was found to be 2002 or 0.20 ppmv. Absolute comparisons of MFLL-derived and in situ-derived CO2 column measurements were made for all daytime flights conducted over Oklahoma and Virginia with an average agreement to within 0.32 ppmv. A major ASCENDS flight test campaign was conducted using the NASA DC-8 during 6-18 July 2010. The MFLL system and associated in situ CO2 instrumentation were operated on DC-8 flights over the Central Valley

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

    Energy Science and Technology Software Center (ESTSC)

    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

  14. Airborne measurements of atmospheric methane column abundance using a pulsed integrated-path differential absorption lidar.

    PubMed

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

    2012-12-01

    We report airborne measurements of the column abundance of atmospheric methane made over an altitude range of 3-11 km using a direct detection integrated-path differential-absorption lidar with a pulsed laser emitting at 1651 nm. The laser transmitter was a tunable, seeded optical parametric amplifier 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. PMID:23207402

  15. 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.

  16. 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

  17. Estimation of signal-to-noise - A new procedure applied to AVIRIS data

    NASA Technical Reports Server (NTRS)

    Curran, Paul J.; Dungan, Jennifer L.

    1989-01-01

    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.

  18. 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.

  19. 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.

  20. 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....

  1. Airborne lidar imaging of salmon.

    PubMed

    Churnside, James H; Wilson, James J

    2004-02-20

    Lidar images of adult salmon are presented. The lidar system is built around a pulsed green laser and a gated intensified CCD camera. The camera gating is timed to collect light scattered from the turbid water below the fish to produce shadows in the images. Image processing increases the estimated contrast-to-noise ratio from 3.4 in the original image to 16.4 by means of a matched filter. PMID:15008549

  2. 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.

  3. Noise Mapping and Annoyance.

    PubMed

    Knauss, D.

    2002-01-01

    The EC has published a Green Paper on noise policy in the EU and has issued a directive on the assessment and reduction of environmental noise. This directive will make noise mapping mandatory for cities with at least 250.000 inhabitants. Due to the development in computer technology it is possible to calculate noise maps for large urban areas using the available data on buildings, ground profile, road and rail traffic. Examples for noise mapping are Birmingham (GB), Linz (A) and various German cities. Based on noise maps and empirical data on the correlation between annoyance and noise levels annoyance maps for different sources (rail, road, aircraft) can be calculated. Under the assumption that the annoyance for the different sources are only weakly correlated, a combined annoyance map can be calculated. In a second step using the distribution of the population the actual number of annoyed people can be evaluated. This analysis can be used, for example, to identify noise hot spots and to assess the impact of major traffic projects - roads, airports- on the noise situation as well as the impact on the population. Furthermore, the combined annoyance maps can be used to investigate on health effects and to check whether or not empirical correlations between annoyance and noise levels are sufficiently correct. PMID:12678944

  4. Urban Noise Protection

    NASA Astrophysics Data System (ADS)

    Jäcker-Cüppers, Michael

    Noise belongs to the severest environmental impairments in towns, with road traffic being the most annoying noise source. The reduction of these impairments and the precaution against new noise impacts is an important task of the communities. However, many of the potential abatement measures are not in the responsibility of the communities. In most European countries, noise emission regulations for road and rail vehicles and outdoor machinery are nowadays enforced by the European Union. Noise reception limits are generally enforced by national laws. Therefore, efficient noise abatement in towns has to be coordinated with the regional, national and supranational, i.e. European noise policy. The most important fields of action for the urban noise abatement are the roads, railways and airports with heavy traffic. For the avoidance of health risks due to noise here short-term reductions are needed, which can generally be achieved only by a combination of measures for which different stakeholders are responsible. This underlines the importance of integrated and coordinated noise abatement concepts.

  5. Mapping of airborne Doppler radar data

    SciTech Connect

    Lee, W.; Dodge, P.; Marks, F.D. Jr.; Hildebrand, P.H. NOAA, Miami, FL )

    1994-04-01

    Two sets of equations are derived to (1) map airborne Doppler radar data from an aircraft-relative coordinate system to an earth-relative coordinate system, and (2) remove the platform motion from the observed Doppler velocities. These equations can be applied to data collected by the National Oceanic and Atmospheric Administration WP-3D system, the National Center for Atmospheric Research Electra Doppler Radar (ELDORA) system, and other airborne radar systems.

  6. 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. PMID:22954401

  7. 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.

  8. Challenges and opportunities of airborne metagenomics.

    PubMed

    Behzad, Hayedeh; Gojobori, Takashi; Mineta, Katsuhiko

    2015-05-01

    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

  9. 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

  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. Silicon Carbide Terahertz Emitting Devices

    NASA Astrophysics Data System (ADS)

    Xuan, G.; Lv, P.-C.; Zhang, X.; Kolodzey, J.; Desalvo, G.; Powell, A.

    2008-05-01

    In recent years, terahertz (THz) sources between 0.1 THz and 10 THz have attracted much attention for imaging and sensing applications. THz emission from radiative transitions in impurity states has been demonstrated in Si and Ge devices by either electrical or optical pumping. Compared to Si as the material for THz emission, the wide-band-gap material SiC exhibits several advantages such as a higher dopant ionization energy, which allows a higher device operating temperature. Combining with its superior material qualities such as high breakdown field and high thermal conductivity, SiC is a promising material for high-temperature and high-power THz emitting devices. This article describes recent progress in using SiC materials to increase the operating temperature and output power of dopant-based THz sources.

  12. 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.

  13. 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

  14. 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

  15. Understanding Slat Noise Sources

    NASA Technical Reports Server (NTRS)

    Khorrami, Medhi R.

    2003-01-01

    Model-scale aeroacoustic tests of large civil transports point to the leading-edge slat as a dominant high-lift noise source in the low- to mid-frequencies during aircraft approach and landing. Using generic multi-element high-lift models, complementary experimental and numerical tests were carefully planned and executed at NASA in order to isolate slat noise sources and the underlying noise generation mechanisms. In this paper, a brief overview of the supporting computational effort undertaken at NASA Langley Research Center, is provided. Both tonal and broadband aspects of slat noise are discussed. Recent gains in predicting a slat s far-field acoustic noise, current shortcomings of numerical simulations, and other remaining open issues, are presented. Finally, an example of the ever-expanding role of computational simulations in noise reduction studies also is given.

  16. Noise and public health.

    PubMed

    Lipscomb, D M; Roettger, R W

    1976-01-01

    Environmental noise has increased to the point that it affects large numbers of people. The most consistently demonstrated health effect of exposure to noise is hearing impairment. Other effects, such as stress reaction, irritability, fatigue and disturbances to physiologic function have been seen in laboratory research but are highly individualized and restricted to such specific populations as industrial workers. Rising background sound levels in communities due to increased traffic flow, industralization, work saving machinery, and other noise sources have caused community noise levels to become dangerously high. This factor is complicated by exposure to high sound level recreational activities with greater frequency and for longer periods. Recognizing the existence of the problem, governmental agencies have begun to identify the scope of the problem, to designate standards and regulations controlling noise sources, and to regulate allowable noise exposure for workers. PMID:10297834

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

    USGS Publications Warehouse

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

    1989-01-01

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

  19. Users guide for an Airborne Windshear Doppler Radar Simulation (AWDRS) program

    NASA Technical Reports Server (NTRS)

    Britt, Charles L.

    1990-01-01

    A description is provided of the Airborne Windshear Doppler Radar Simulation (AWDRS) program developed for NASA-Langley by the Research Triangle Institute. The radar simulation program is a comprehensive calculation of the signal characteristics and expected outputs of an airborne coherent pulsed Doppler radar system viewing a low level microburst along or near the approach path of the aircraft. The detailed nature of the simulation permits the quick evaluation of proposed trade-offs in radar system parameters and the evaluation of the performance of proposed configurations in various microburst/clutter environments. The simulation also provides a test bed for various proposed signal processing techniques for minimizing the effects of noise, phase jitter, and ground clutter and maximizing the useful information derived for avoidance of microburst windshear by aircraft.

  20. Active noise silencing

    SciTech Connect

    Jay, M.A.

    1995-02-01

    Many natural gas compressor stations which were previously located away from residential areas are now being encroached upon by surrounding building developments. An increased awareness of community noise issues has proved to be the impetus for investigating and developing more effective noise control methods and treatments for natural gas compressor facilities. This project investigates the feasibility of applying Active Noise Cancellation (ANC) to the exhaust of a large, internal combustion reciprocating type engine.

  1. Prediction of airframe noise

    NASA Technical Reports Server (NTRS)

    Hardin, J. C.; Fratello, D. J.; Hayden, R. E.; Kadman, Y.; Africk, S.

    1975-01-01

    Methods of predicting airframe noise generated by aircraft in flight under nonpowered conditions are discussed. Approaches to predictions relying on flyover data and component theoretical analyses are developed. A nondimensional airframe noise spectrum of various aircraft is presented. The spectrum was obtained by smoothing all the measured spectra to remove any peculiarities due to airframe protrusions, normalizing each spectra by its overall sound pressure level and a characteristics frequency, and averaging the spectra together. A chart of airframe noise sources is included.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. Perspectives on jet noise

    NASA Technical Reports Server (NTRS)

    Ribner, H. S.

    1981-01-01

    Jet noise is a byproduct of turbulence. Until recently turbulence was assumed to be known statistically, and jet noise was computed therefrom. As a result of new findings though on the behavior of vortices and instability waves, a more integrated view of the problem has been accepted lately. After presenting a simple view of jet noise, the paper attempts to resolve the apparent differences between Lighthill's and Lilley's interpretations of mean-flow shear, and examines a number of ad hoc approaches to jet noise suppression.

  7. 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.

  8. 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

  9. 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.

  10. Identification and classification of noise sources in a chain conveyor

    NASA Astrophysics Data System (ADS)

    Homer, John P.; Vipperman, Jeffrey S.; Reeves, Efrem R.

    2002-05-01

    Noise induced hearing loss (NIHL) is one of the most significant disabilities of workers in the mining industry. In response, the National Institute of Occupational Safety and Health (NIOSH) is conducting a study associated with mining equipment. This study outlines the analysis of a chain conveyor. Band-limited accelerometer, sound-intensity, far-field and near-field microphone measurements were taken along the conveyor section. The sound intensity measurements were used to identify areas with high noise as well as to calculate and 1/3-octave sound power levels. The total sound power results were used to classify the dominant noise sources where the 1/3-octave sound power results were used to identify the most contributive frequency bands to the overall noise of the system. Coherence analysis was performed between accelerometer and microphone measurements to identify structure-borne and air-borne noise paths of the system. Summary results from the analysis include recommendations for transmission control and damping devices and their ability to reduce noise to regulatory acceptable levels.

  11. 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.

  12. Relative intensity noise in high speed microcavity laser

    NASA Astrophysics Data System (ADS)

    Tan, F.; Wu, M. K.; Liu, M.; Feng, M.; Holonyak, N.

    2013-09-01

    We have fabricated a high speed single mode microcavity laser of the form of oxide-confined vertical cavity surface emitting laser (VCSEL) and achieved an ultralow threshold current (ITH = 0.13 mA at 20 °C) with lasing wavelength at 837 nm. The optical spectrum of the microcavity VCSEL exhibits a mode spacing of 3.1 nm, which is corresponding to an optical modal cavity dimension of 2.5 μm. The device exhibits an enhanced modulation bandwidth of 22.6 GHz and a thermal noise limited laser intensity noise (electrical power spectral density of laser intensity noise below the thermal noise floor -174 dBm/Hz) as a consequence of low power laser operation and reduced mode competition in the microcavity.

  13. 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. PMID:25115518

  14. A study of helicopter main rotor noise in hover

    NASA Technical Reports Server (NTRS)

    Kitaplioglu, C.; Kinney, C.

    1986-01-01

    Some fundamental aspects of rotor noise generation and radiation are presented. Data on which the study is based were obtained during a hover test at the NASA Ames Outdoor Aerodynamic Research Facility of a one-sixth-scale, four-bladed, helicopter rotor. The test site provided an open environment ideal for acquiring good acoustic data. Information is presented on the delineation between the acoustic near-field and far-field, and on the effect of a simple boundary-layer trip device. Data obtained at near-zero thrust conditions indicate that it is possible to isolate thickness noise with minimum contamination by loading noise effects. An abrupt change in the nature of the emitted noise at high-thrust conditions is investigated and is related to unsteady wake/support interaction.

  15. 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.

  16. 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…

  17. 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.

  18. Geodetic and geophysical results from a Taiwan airborne gravity survey: Data reduction and accuracy assessment

    NASA Astrophysics Data System (ADS)

    Hwang, Cheinway; Hsiao, Yu-Shen; Shih, Hsuan-Chang; Yang, Ming; Chen, Kwo-Hwa; Forsberg, Rene; Olesen, Arne V.

    2007-04-01

    An airborne gravity survey was conducted over Taiwan using a LaCoste and Romberg (LCR) System II air-sea gravimeter with gravity and global positioning system (GPS) data sampled at 1 Hz. The aircraft trajectories were determined using a GPS network kinematic adjustment relative to eight GPS tracking stations. Long-wavelength errors in position are reduced when doing numerical differentiations for velocity and acceleration. A procedure for computing resolvable wavelength of error-free airborne gravimetry is derived. The accuracy requirements of position, velocity, and accelerations for a 1-mgal accuracy in gravity anomaly are derived. GPS will fulfill these requirements except for vertical acceleration. An iterative Gaussian filter is used to reduce errors in vertical acceleration. A compromising filter width for noise reduction and gravity detail is 150 s. The airborne gravity anomalies are compared with surface values, and large differences are found over high mountains where the gravity field is rough and surface data density is low. The root mean square (RMS) crossover differences before and after a bias-only adjustment are 4.92 and 2.88 mgal, the latter corresponding to a 2-mgal standard error in gravity anomaly. Repeatability analyses at two survey lines suggest that GPS is the dominating factor affecting the repeatability. Fourier transform and least-squares collocation are used for downward continuation, and the latter produces a better result. Two geoid models are computed, one using airborne and surface gravity data and the other using surface data only, and the former yields a better agreement with the GPS-derived geoidal heights. Bouguer anomalies derived from airborne gravity by a rigorous numerical integration reveal important tectonic features.

  19. 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.

  20. 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.

  1. 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.

  2. 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)

  3. Predicted airframe noise levels

    NASA Astrophysics Data System (ADS)

    Raney, J. P.

    1980-09-01

    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. 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…

  5. 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,…

  6. 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.

  7. 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…

  8. 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

  9. 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.

  10. 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.

  11. Mapping permafrost with airborne electromagnetics

    NASA Astrophysics Data System (ADS)

    Minsley, B. J.; Ball, L. B.; Bloss, B. R.; Kass, A.; Pastick, N.; Smith, B. D.; Voss, C. I.; Walsh, D. O.; Walvoord, M. A.; Wylie, B. K.

    2014-12-01

    Permafrost is a key characteristic of cold region landscapes, yet detailed assessments of how the subsurface distribution of permafrost impacts the environment, hydrologic systems, and infrastructure are lacking. Data acquired from several airborne electromagnetic (AEM) surveys in Alaska provide significant new insight into the spatial extent of permafrost over larger areas (hundreds to thousands of square kilometers) than can be mapped using ground-based geophysical methods or through drilling. We compare several AEM datasets from different areas of interior Alaska, and explore the capacity of these data to infer geologic structure, permafrost extent, and related hydrologic processes. We also assess the impact of fires on permafrost by comparing data from different burn years within similar geological environments. Ultimately, interpretations rely on understanding the relationship between electrical resistivity measured by AEM surveys and the physical properties of interest such as geology, permafrost, and unfrozen water content in the subsurface. These relationships are often ambiguous and non-unique, so additional information is useful for reducing uncertainty. Shallow (upper ~1m) permafrost and soil characteristics identified from remotely sensed imagery and field observations help to constrain and aerially extend near-surface AEM interpretations, where correlations between the AEM and remote sensing data are identified using empirical multivariate analyses. Surface nuclear magnetic resonance (sNMR) measurements quantify the contribution of unfrozen water at depth to the AEM-derived electrical resistivity models at several locations within one survey area. AEM surveys fill a critical data gap in the subsurface characterization of permafrost environments and will be valuable in future mapping and monitoring programs in cold regions.

  12. Multilayer polymer light emitting devices

    NASA Astrophysics Data System (ADS)

    Barcikowski, Zachary; Thomas, Adam; Tzolov, Marian

    2013-03-01

    The interplay of device layers and their interfaces is a major area of study in Polymer Light Emitting Devices (PLEDs). Many factors such as the degradation, efficiency, and overall performance depend on how these layers interact with each other. A fundamental understanding of the interfaces of these layers can lend to better performing devices using a multitude of organic polymers deposited in conjunction with each other in several ways. We have studied basic PLED devices in which we vary the emissive layer used, along with final bake temperatures. Devices include a glass substrate with Indium Tin Oxide anode, Aluminum cathode, and Plexcore Hole Injection layer. The active polymer films were spin casted from solution of MEH-PPV and PFO. Single layer and dual layers of several polymers are studied by examining current-voltage characteristics, film densities, impedance measurements, light emission, and efficiency calculations. We have found that not only do dual layers positively alter the performance of the device in the majority of cases, but the solvents in which each layer is originally in when deposited affects the formation of the interface, thereby altering the device mechanisms.

  13. Community noise model

    SciTech Connect

    Not Available

    1989-09-01

    MVMA has sponsored a study to assist the motor vehicle manufacturers and others in assessing the impact of motor vehicle noise on the community. As part of this study, a computer model was developed to quantify, by mathematical simulation, the impact of traffic noise on the community, with particular emphasis on passenger cars, light trucks and vans under 10,000 pounds gross vehicle weight rating. The primary objective of the program was to evaluate the incremental changes in exposure to traffic noise which would result from the promulgation of various new-vehicle emission standards and to compare these incremental changes with those which result from alternative approaches to vehicle noise abatement. The model is available for use on microcomputers and is capable of evaluating local, as well as national, noise control strategies.

  14. [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

  15. Rotorcraft Noise Model

    NASA Technical Reports Server (NTRS)

    Lucas, Michael J.; Marcolini, Michael A.

    1997-01-01

    The Rotorcraft Noise Model (RNM) is an aircraft noise impact modeling computer program being developed for NASA-Langley Research Center which calculates sound levels at receiver positions either on a uniform grid or at specific defined locations. The basic computational model calculates a variety of metria. Acoustic properties of the noise source are defined by two sets of sound pressure hemispheres, each hemisphere being centered on a noise source of the aircraft. One set of sound hemispheres provides the broadband data in the form of one-third octave band sound levels. The other set of sound hemispheres provides narrowband data in the form of pure-tone sound pressure levels and phase. Noise contours on the ground are output graphically or in tabular format, and are suitable for inclusion in Environmental Impact Statements or Environmental Assessments.

  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. Active airborne contamination control using electrophoresis

    SciTech Connect

    Veatch, B.D.

    1994-06-01

    In spite of our best efforts, radioactive airborne contamination continues to be a formidable problem at many of the Department of Energy (DOE) weapons complex sites. For workers that must enter areas with high levels of airborne contamination, personnel protective equipment (PPE) can become highly restrictive, greatly diminishing productivity. Rather than require even more restrictive PPE for personnel in some situations, the Rocky Flats Plant (RFP) is actively researching and developing methods to aggressively combat airborne contamination hazards using electrophoretic technology. With appropriate equipment, airborne particulates can be effectively removed and collected for disposal in one simple process. The equipment needed to implement electrophoresis is relatively inexpensive, highly reliable, and very compact. Once airborne contamination levels are reduced, less PPE is required and a significant cost savings may be realized through decreased waste and maximized productivity. Preliminary ``cold,`` or non-radioactive, testing results at the RFP have shown the technology to be effective on a reasonable scale, with several potential benefits and an abundance of applications.

  18. Airborne 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.

  19. 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.

  20. 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

  1. Multi-mode multistatics for passive/active airborne surveillance

    NASA Astrophysics Data System (ADS)

    Ogrodnik, Robert F.

    1986-07-01

    The increasing performance demands for air surveillance assets, as well as the necessity for continued surveillance operations in the presence of enemy jamming anti-radiation missile (ARM) attacks, have increased interest in passive surveillance, in particular multi-mode passive/active multistatic sensing. The use of noncooperative radiation as illuminators of opportunity combined with passive surveillance electromagnetic support measurement (ESM) sensors opens new horizons to multistatic surveillance from a passive airborne platform. Research and field tests have been conducted on ESM augmented bistatics as well as noncooperative multistatics which support the development of airborne multi-mode passive surveillance technology. This work has been conducted under such programs as the Bistatic Enhanced Altimeter Detection (BEAD) and the noncooperative multistatic Passive Coherent Location (PCL). Both BEAD and PCL technology directly support the receiver, signal processing and target location/tracking operations necessary for passive surveillance. The demonstrated technologies for EM interference rejection and multistatic multi-target tracking and location under PCL provide a promising performance bench mark for passive surveillance in the presence of a complex electromagnetic environment. Passive receiver intercept performance under BEAD has provided a receiver design baseline for both look-down and look-up surveillance applications. The technologies under development in BEAD and PCL are presented along with the field test results and the sensor concepts. In particular, spin-off data such as bistatic look-down clutter, noise-floor limitation of noncooperative multistatics and sensitivity limitations set by passive surveillance using signal intercept techniques and illuminators of opportunity are provided.

  2. 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.

  3. A power transformer as a source of noise.

    PubMed

    Zawieska, Wiktor Marek

    2007-01-01

    This article presents selected results of analyses and simulations carried out as part of research performed at the Central Institute of Labor Protection - the National Research Institute (CIOP-PIB) in connection with the development of a system for active reduction of noise emitted by high power electricity transformers. This analysis covers the transformer as a source of noise as well as a mathematical description of the phenomenon of radiation of vibroacoustic energy through a transformer enclosure modeled as a vibrating rectangular plate. Also described is an acoustic model of the transformer in the form of an array of loudspeakers. PMID:18082020

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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

  9. 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. PMID:26803684

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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. PMID:18681585

  15. Broadband rotor noise analyses

    NASA Technical Reports Server (NTRS)

    George, A. R.; Chou, S. T.

    1984-01-01

    The various mechanisms which generate broadband noise on a range of rotors studied include load fluctuations due to inflow turbulence, due to turbulent boundary layers passing the blades' trailing edges, and due to tip vortex formation. Existing analyses are used and extensions to them are developed to make more accurate predictions of rotor noise spectra and to determine which mechanisms are important in which circumstances. Calculations based on the various prediction methods in existing experiments were compared. The present analyses are adequate to predict the spectra from a wide variety of experiments on fans, full scale and model scale helicopter rotors, wind turbines, and propellers to within about 5 to 10 dB. Better knowledge of the inflow turbulence improves the accuracy of the predictions. Results indicate that inflow turbulence noise depends strongly on ambient conditions and dominates at low frequencies. Trailing edge noise and tip vortex noise are important at higher frequencies if inflow turbulence is weak. Boundary layer trailing edge noise, important, for large sized rotors, increases slowly with angle of attack but not as rapidly as tip vortex noise.

  16. [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. PMID:9483870

  17. Broadband rotor noise analyses

    NASA Astrophysics Data System (ADS)

    George, A. R.; Chou, S. T.

    1984-04-01

    The various mechanisms which generate broadband noise on a range of rotors studied include load fluctuations due to inflow turbulence, due to turbulent boundary layers passing the blades' trailing edges, and due to tip vortex formation. Existing analyses are used and extensions to them are developed to make more accurate predictions of rotor noise spectra and to determine which mechanisms are important in which circumstances. Calculations based on the various prediction methods in existing experiments were compared. The present analyses are adequate to predict the spectra from a wide variety of experiments on fans, full scale and model scale helicopter rotors, wind turbines, and propellers to within about 5 to 10 dB. Better knowledge of the inflow turbulence improves the accuracy of the predictions. Results indicate that inflow turbulence noise depends strongly on ambient conditions and dominates at low frequencies. Trailing edge noise and tip vortex noise are important at higher frequencies if inflow turbulence is weak. Boundary layer trailing edge noise, important, for large sized rotors, increases slowly with angle of attack but not as rapidly as tip vortex noise.

  18. 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, ...

  19. Approaches to detection of airborne biological agents

    NASA Astrophysics Data System (ADS)

    Chang, An-Cheng; Tabacco, Mary Beth

    2009-05-01

    Three approaches to detection of biological agents based on biological processes will be presented. The first example demonstrates the use of dendrimers to deliver a membrane-impermeable fluorescent dye into live bacteria, similar to viral infection and delivery of DNA/RNA into a bacterial cell. The second example mimics collection and capture of airborne biological particles by the respiratory mucosa through the use of a hygroscopic sensing membrane. The third example is based on the use of multiple fluorescent probes with diverse functionalities to detect airborne biological agents in a manner similar to the olfactory receptors in the nasal tract.

  20. 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.

  1. 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)

  2. 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.

  3. 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 .

  4. Hypermedicalization in White Noise.

    PubMed

    Benson, Josef

    2015-09-01

    The Nazis hijacked Germany's medical establishment and appropriated medical language to hegemonize their ideology. In White Noise, shifting medical information stifles the public into docility. In Nazi Germany the primacy of language and medical authority magnified the importance of academic doctors. The muddling of identities caused complex insecurities and the need for psychological doubles. In White Noise, Professor Gladney is driven by professional insecurities to enact a double in Murray. Through the manipulation of language and medical overreach the U.S., exemplified in the novel White Noise, has become a hypermedicalized society where the spirit of the Hippocratic Oath has eroded. PMID:24458659

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. NASA Airborne Lidar 1982-1984 Flights Data and Information

    Atmospheric Science Data Center

    2014-08-06

    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 ...

  10. 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...

  11. 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....

  12. 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...

  13. 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...

  14. 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....

  15. 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...

  16. 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...

  17. 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...

  18. 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....

  19. 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...

  20. 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...

  1. 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....

  2. 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...

  3. 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....

  4. 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...

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Otoacoustic emission sensitivity to exposure to styrene and noise.

    PubMed

    Sisto, R; Cerini, L; Gatto, M P; Gherardi, M; Gordiani, A; Sanjust, F; Paci, E; Tranfo, G; Moleti, A

    2013-11-01

    The ototoxic effect of the exposure to styrene is evaluated, also in the presence of simultaneous exposure to noise, using otoacoustic emissions as biomarkers of mild cochlear damage. Transient-evoked and distortion product otoacoustic emissions were recorded and analyzed in a sample of workers (15 subjects) exposed to styrene and noise in a fiberglass manufacturing facility and in a control group of 13 non-exposed subjects. Individual exposure monitoring of the airborne styrene concentrations was performed, as well as biological monitoring, based on the urinary concentration of two styrene metabolites, the Mandelic and Phenylglyoxylic acids. Noise exposure was evaluated using wearable phonometers, and hearing loss with pure tone audiometry. Due to their different job tasks, one group of workers was exposed to high noise and low styrene levels, another group to higher styrene levels, close to the limit of 20 ppm, and to low noise levels. A significant negative correlation was found between the otoacoustic emission levels and the concentration of the styrene urinary metabolites. Otoacoustic emissions, and particularly distortion products, were able to discriminate the exposed workers from the controls, providing also a rough estimate of the slope of the dose-response relation between otoacoustic levels and styrene exposure. PMID:24180784

  10. Noise in Mexico City

    NASA Astrophysics Data System (ADS)

    Beristain, Sergio

    2001-05-01

    Mexico City is known to be the largest city in the world, inhabited by some 20 percent of the national population, so noise pollution is not strange to it, particularly in view of the fact that industry is not concentrated, but rather spread throughout the city. The international airport also lies within the city limits, in the midst of residential areas. The heavy traffic during rush hours in the morning and in the evening and the activities of the populace, together with special events, produce a noise problem that is difficult to assess and to solve. Nevertheless, with educational programs begun several years ago and noise campaigns planned for the near future, in addition to existing regulations, the problem is not completely out of control. This paper presents a discussion of the general noise problem and describes how authorities and institutions are dealing with it.

  11. Airframe noise prediction evaluation

    NASA Technical Reports Server (NTRS)

    Yamamoto, Kingo J.; Donelson, Michael J.; Huang, Shumei C.; Joshi, Mahendra C.

    1995-01-01

    The objective of this study is to evaluate the accuracy and adequacy of current airframe noise prediction methods using available airframe noise measurements from tests of a narrow body transport (DC-9) and a wide body transport (DC-10) in addition to scale model test data. General features of the airframe noise from these aircraft and models are outlined. The results of the assessment of two airframe prediction methods, Fink's and Munson's methods, against flight test data of these aircraft and scale model wind tunnel test data are presented. These methods were extensively evaluated against measured data from several configurations including clean, slat deployed, landing gear-deployed, flap deployed, and landing configurations of both DC-9 and DC-10. They were also assessed against a limited number of configurations of scale models. The evaluation was conducted in terms of overall sound pressure level (OASPL), tone corrected perceived noise level (PNLT), and one-third-octave band sound pressure level (SPL).

  12. NASA Jet Noise Research

    NASA Technical Reports Server (NTRS)

    Henderson, Brenda

    2012-01-01

    The presentation highlights jet-noise research conducted in the Subsonic Fixed Wing, Supersonics, and Environmentally Responsible Aviation Projects in the Fundamental Aeronautics Program at NASA. The research efforts discussed include NASA's updated Aircraft NOise Prediction Program (ANOPP2), acoustic-analogy-based prediction tools, jet-surface-interaction studies, plasma-actuator investigations, N+2 Supersonics Validation studies, rectangular-jet experiments, twin-jet experiments, and Hybrid Wind Body (HWB) activities.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Propeller noise prediction

    NASA Technical Reports Server (NTRS)

    Zorumski, W. E.

    1983-01-01

    Analytic propeller noise prediction involves a sequence of computations culminating in the application of acoustic equations. The prediction sequence currently used by NASA in its ANOPP (aircraft noise prediction) program is described. The elements of the sequence are called program modules. The first group of modules analyzes the propeller geometry, the aerodynamics, including both potential and boundary layer flow, the propeller performance, and the surface loading distribution. This group of modules is based entirely on aerodynamic strip theory. The next group of modules deals with the actual noise prediction, based on data from the first group. Deterministic predictions of periodic thickness and loading noise are made using Farassat's time-domain methods. Broadband noise is predicted by the semi-empirical Schlinker-Amiet method. Near-field predictions of fuselage surface pressures include the effects of boundary layer refraction and (for a cylinder) scattering. Far-field predictions include atmospheric and ground effects. Experimental data from subsonic and transonic propellers are compared and NASA's future direction is propeller noise technology development are indicated.

  18. 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

  19. 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

  20. 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 ...

  1. Organic emitters: Light-emitting fabrics

    NASA Astrophysics Data System (ADS)

    Ortí, Enrique; Bolink, Henk J.

    2015-04-01

    Light-emitting fibres that suit integration with textiles are prepared by dip-coating a steel wire with an electroluminescent material and then cleverly wrapping the structure with a carbon nanotube sheet that functions as a transparent electrode.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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 ...

  7. Mapping Waterhyacinth Infestations Using Airborne Hyperspectral Imagery

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Waterhyacinth [Eichhornia crassipes (Mart.) Solms] is an exotic aquatic weed that often invades and clogs waterways in many tropical and subtropical regions of the world. The objective of this study was to evaluate airborne hyperspectral imagery and different image classification techniques for mapp...

  8. 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)

  9. 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.

  10. Airborne sensor integration for quick reaction programs

    NASA Astrophysics Data System (ADS)

    Gosian, Gregory; Mason, Kenneth; Servoss, Thomas; Brower, Bernard; Pellechia, Matthew

    2010-04-01

    In this paper we present an approach to integrate sensors to meet the demanding requirements of Quick Reaction Capability (QRC) airborne programs. Traditional airborne sensors are generally highly integrated and incorporate custom sensor technologies and interfaces. Custom solutions and new technologies often require significant engineering to achieve a high technology readiness level (TRL) and to meet the overall mission objective. Our approach differs from traditional approaches in that we strive to achieve an integrated solution through regular review, assessment, and identification of relevant industry "best athlete" technologies. Attention is focused on solution providers that adhere to standard interfaces and formats, incorporate non-proprietary techniques, are deemed highly-reliable/repeatable, and enable assembly production. Processes and engineering tools/methods have traditionally been applied to dozens of longer-acquisition space-based ISR programs over 50 years. We have recently leveraged these techniques to solve airborne Intelligence, Surveillance and Reconnaissance (ISR) mission challenges. This presentation describes and illustrates key aspects and examples of these techniques, solving real-world airborne mission needs.

  11. Airborne hyperspectral detection of small changes.

    PubMed

    Eismann, Michael T; Meola, Joseph; Stocker, Alan D; Beaven, Scott G; Schaum, Alan P

    2008-10-01

    Hyperspectral change detection offers a promising approach to detect objects and features of remotely sensed areas that are too difficult to find in single images, such as slight changes in land cover and the insertion, deletion, or movement of small objects, by exploiting subtle differences in the imagery over time. Methods for performing such change detection, however, must effectively maintain invariance to typically larger image-to-image changes in illumination and environmental conditions, as well as misregistration and viewing differences between image observations, while remaining sensitive to small differences in scene content. Previous research has established predictive algorithms to overcome such natural changes between images, and these approaches have recently been extended to deal with space-varying changes. The challenges to effective change detection, however, are often exacerbated in an airborne imaging geometry because of the limitations in control over flight conditions and geometry, and some of the recent change detection algorithms have not been demonstrated in an airborne setting. We describe the airborne implementation and relative performance of such methods. We specifically attempt to characterize the effects of spatial misregistration on change detection performance, the efficacy of class-conditional predictors in an airborne setting, and extensions to the change detection approach, including physically motivated shadow transition classifiers and matched change filtering based on in-scene atmospheric normalization. PMID:18830283

  12. 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.

  13. Toolsets for Airborne Data Beta Release

    Atmospheric Science Data Center

    2014-09-17

    ... use, is now available. This beta-release is an intuitive user interface for variable selection across different airborne field studies ... we plan to add DISCOVER-AQ Colorado and SEAC4RS to the TAD database. We are currently focused on the in situ measurements and we want to ...

  14. Materiel requirements for airborne minefield detection system

    NASA Astrophysics Data System (ADS)

    Bertsche, Karl A.; Huegle, Helmut

    1997-07-01

    Within the concept study, Material Requirements for an airborne minefield detection systems (AMiDS) the following topics were investigated: (i) concept concerning airborne minefield detection technique sand equipment, (ii) verification analysis of the AMiDS requirements using simulation models and (iii) application concept of AMiDS with regard o tactics and military operations. In a first approach the problems concerning unmanned airborne minefield detection techniques within a well-defined area were considered. The complexity of unmanned airborne minefield detection is a result of the following parameters: mine types, mine deployment methods, tactical requirements, topography, weather conditions, and the size of the area to be searched. In order to perform the analysis, a simulation model was developed to analyze the usability of the proposed remote controlled air carriers. The basic flight patterns for the proposed air carriers, as well as the preparation efforts of military operations and benefits of such a system during combat support missions were investigated. The results of the conceptual study showed that a proposed remote controlled helicopter drone could meet the stated German MOD scanning requirements of mine barriers. Fixed wing air carriers were at a definite disadvantage because of their inherently large turning loops. By implementing a mine detection system like AMiDS minefields can be reconnoitered before an attack. It is therefore possible either to plan, how the minefields can be circumvented or where precisely breaching lanes through the mine barriers are to be cleared for the advancing force.

  15. Airborne UV Lidar for Forest Parameter Retrievals

    NASA Astrophysics Data System (ADS)

    Shang, Xiaoxia; Chazette, Patrick; Totems, Julien

    2016-06-01

    A full-waveform UV lidar performed airborne measurements over several temperate and tropical forests sites. The structural and ecological parameters (canopy height, quadratic mean canopy height and apparent foliage) were extracted from lidar backscattered profiles. The aboveground carbon and leaf area index are also evaluated from lidar measurements.

  16. Photochemistry of Organic Light-Emitting Diodes

    SciTech Connect

    Ehara, Masahiro; Nakatsuji, Hiroshi

    2007-12-26

    The optical properties and excited-state geometries of some organic light-emitting diodes have been investigated by the SAC-CI method. The absorption and emission spectra have been predicted in high accuracy and the chain-length dependence of transition energies has been precisely reproduced. The present study provides the useful basis for the theoretical design predicting the photo-physical properties of the organic light-emitting diodes.

  17. 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.

  18. 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.

  19. 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.

  20. Aircraft noise - Different ways to monitor the noise load

    NASA Astrophysics Data System (ADS)

    Bekebrede, G.

    Measures taken by the Dutch government to reduce aircraft-noise disturbances including the establishment of noise zones in which subsequent building is forbidden, while already existing homes are provided with noise insulation are discussed. To ensure accurate noise monitoring, the following recommendations were made by the NLR: (1) regular noise load calculations, utilizing aircraft noise and performance data, the air traffic mix, and flight route information; (2) flight track monitoring, performed by a computerized Flight Track and Aircraft Noise Monitoring System which identifies all aircraft deviating from the prescribed track (i.e., flying over congested regions); and (3) actual noise monitoring, to guard the noise level at a specific noise-sensitive area in close proximity to the airfield, such as a hospital.

  1. 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.

  2. 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

  3. 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.

  4. 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. PMID:24866988

  5. 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.

  6. 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.

  7. Fundamentals of noise control engineering

    SciTech Connect

    Miller, R.K.; Thumann, A.

    1986-01-01

    This reference provides coverage of noise control engineering. Techniques are presented in precise terms for both acoustical design of new facilities and cost-effective noise reduction in existing facilities. Examples illustrate how to design acoustical enclosures, apply silencing equipment, estimate equipment noise and meet noise criteria for communities.

  8. 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.

  9. LSNR Airborne LIDAR Mapping System Design and Early Results (Invited)

    NASA Astrophysics Data System (ADS)

    Shrestha, K.; Carter, W. E.; Slatton, K. C.

    2009-12-01

    Low signal-to-noise ratio (LSNR) detection techniques allow for implementation of airborne light detection and range (LIDAR) instrumentation aboard platforms with prohibitive power, size, and weight restrictions. The University of Florida has developed the Coastal Area Tactical-mapping System (CATS), a prototype LSNR LIDAR system capable of single photon laser ranging. CATS is designed to operate in a fixed-wing aircraft flying 600 m above ground level, producing 532 nm, 480 ps, 3 μJ output pulses at 8 kHz. To achieve continuous coverage of the terrain with 20 cm spatial resolution in a single pass, a 10x10 array of laser beamlets is scanned. A Risley prism scanner (two rotating V-coated optical wedges) allows the array of laser beamlets to be deflected in a variety of patterns, including conical, spiral, and lines at selected angles to the direction of flight. Backscattered laser photons are imaged onto a 100 channel (10x10 segmented-anode) photomultiplier tube (PMT) with a micro-channel plate (MCP) amplifier. Each channel of the PMT is connected to a multi-stop 2 GHz event timer. Here we report on tests in which ranges for known targets were accumulated for repeated laser shots and statistical analyses were applied to evaluate range accuracy, minimum separation distance, bathymetric mapping depth, and atmospheric scattering. Ground-based field test results have yielded 10 cm range accuracy and sub-meter feature identification at variable scan settings. These experiments also show that a secondary surface can be detected at a distance of 15 cm from the first. Range errors in secondary surface identification for six separate trials were within 7.5 cm, or within the timing resolution limit of the system. Operating at multi-photon sensitivity may have value for situations in which high ambient noise precludes single-photon sensitivity. Low reflectivity targets submerged in highly turbid waters can cause detection issues. CATS offers the capability to adjust the

  10. 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

  11. 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.

  12. 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.

  13. Helicopter rotor trailing edge noise

    NASA Technical Reports Server (NTRS)

    Schlinker, R. H.; Amiet, R. K.

    1981-01-01

    An experimental and theoretical study was conducted to assess the importance of trailing edge noise as a helicopter main rotor broadband noise source. The noise mechanism was isolated by testing a rotor blade segment in an open jet acoustic wind tunnel at close to full scale Reynolds numbers. Boundary layer data and acoustic data were used to develop scaling laws and assess a first principles trailing edge noise theory. Conclusions from the isolated blade study were analytically transformed to the rotating frame coordinate system to develop a generalized rotor noise prediction. Trailing edge noise was found to contribute significantly to the total helicopter noise spectrum at high frequencies.

  14. Helicopter rotor trailing edge noise

    NASA Astrophysics Data System (ADS)

    Schlinker, R. H.; Amiet, R. K.

    1981-10-01

    An experimental and theoretical study was conducted to assess the importance of trailing edge noise as a helicopter main rotor broadband noise source. The noise mechanism was isolated by testing a rotor blade segment in an open jet acoustic wind tunnel at close to full scale Reynolds numbers. Boundary layer data and acoustic data were used to develop scaling laws and assess a first principles trailing edge noise theory. Conclusions from the isolated blade study were analytically transformed to the rotating frame coordinate system to develop a generalized rotor noise prediction. Trailing edge noise was found to contribute significantly to the total helicopter noise spectrum at high frequencies.

  15. 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.

  16. 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.

  17. Subradiant spontaneous undulator emission through collective suppression of shot noise

    NASA Astrophysics Data System (ADS)

    Ratner, D.; Hemsing, E.; Gover, A.; Marinelli, A.; Nause, A.

    2015-05-01

    The phenomenon of Dicke's subradiance, in which the collective properties of a system suppress radiation, has received broad interest in atomic physics. Recent theoretical papers in the field of relativistic electron beams have proposed schemes to achieve subradiance through suppression of shot noise current fluctuations. The resulting "quiet" beam generates less spontaneous radiation than emitted even by a shot noise beam when oscillating in an undulator. Quiet beams could have diverse accelerator applications, including lowering power requirements for seeded free-electron lasers and improving efficiency of hadron cooling. In this paper we present experimental observation of a strong reduction in undulator radiation, demonstrating the feasibility of noise suppression as a practical tool in accelerator physics.

  18. 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

  19. Optimization of determination of platinum group elements in airborne particulate matter by inductively coupled plasma mass spectrometry.

    PubMed

    Bujdoš, Marek; Hagarová, Ingrid; Matúš, Peter; Canecká, Lucia; Kubová, Jana

    2012-03-01

    Determination of automotive traffic-emitted platinum group metals (PGM) by inductively coupled plasma quadrupole mass spectrometry (ICP-MS) was optimized. The interferences from Sr, Cu, Pb, Y, Cd, Zr and Hf were evaluated using model solutions. Plasma radiofrequency (RF) power and nebulizer gas flow were optimized for 103Rh, 105Pd, 108Pd and 195Pt. Two standard reference materials were analyzed: SARM-7 Platinum ore and BCR-723 Road dust. The optimized procedure was used to analyze samples of airborne particulate matter collected in the urban site with heavy automotive traffic in the centre of Bratislava, Slovakia. PMID:24061181

  20. 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.

  1. Noise: a forgotten environmental problem

    SciTech Connect

    Kloos, J.B.

    1980-01-01

    Highway traffic noise is a serious problem for communities. The traffic noise can be lessened by source controls. The impact of the noise can be mitigated with barriers built along heavily traveled roads. However, the most promising long-range solution is noise compatible land use planning at the local level. Low cost methods are available to prevent noise problems from ever occuring. The Federal Highway Administration is attempting to encourage local officials to use these methods.

  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. 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.

  4. Design and performance of a fiber array coupled multi-channel photon counting, 3D imaging, airborne lidar system

    NASA Astrophysics Data System (ADS)

    Huang, Genghua; Shu, Rong; Hou, Libing; Li, Ming

    2014-06-01

    Photon counting lidar has an ultra-high sensitivity which can be hundreds even thousands of times higher than the linear detection lidar. It can significantly increase the system's capability of detection rang and imaging density, saving size and power consumings in airborne or space-borne applications. Based on Geiger-mode Si avalanche photodiodes (Si-APD), a prototype photon counting lidar which used 8 APDs coupled with a 1×8-pixel fiber array has been made in June, 2011. The experiments with static objects showed that the photon counting lidar could operate in strong solar background with 0.04 receiving photoelectrons on average. Limited by less counting times in moving platforms, the probability of detection and the 3D imaging density would be lower than that in static platforms. In this paper, a latest fiber array coupled multi-channel photon counting, 3D imaging, airborne lidar system is introduced. The correlation range receiver algorithm of photon counting 3D imaging is improved for airborne signal photon events extraction and noise filter. The 3D imaging experiments in the helicopter shows that the false alarm rate is less than 6×10-7, and the correct rate is better than 99.9% with 4 received photoelectrons and 0.7MHz system noise on average.

  5. Helicopter internal noise

    NASA Astrophysics Data System (ADS)

    Niesl, G.; Laudien, E.

    1994-09-01

    Compared to fixed wing aircraft, helicopter interior noise is higher, and subjectively more annoying. This is mainly due to discrete frequencies by the main transmission system, and also from other components like main and tail rotor, engines, or cooling fans. Up to now, mainly passive measures have been used for interior noise reduction. Despite intensive experimental and theoretical investigation to improve acoustic treatment, their weight penalties remain high especially in the low frequency range. Here, active noise control offers additional capacities without excessive weight efforts. Loud-speaker based systems are sufficiently well developed for implementing a prototype system in the helicopter. Two other principles are in development: active panel control which introduces mechanical actuators to excite the cabin walls, and active control of gearbox struts with actuators in the load path between gearbox and fuselage.

  6. 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.

  7. Network structure controls noise

    NASA Astrophysics Data System (ADS)

    Das, Jayajit; Raychaudhuri, Subhadip

    2004-03-01

    Biochemical reactions often involve low copy number of reactant molecules. Bio-networks, however, control the intrinsic noise arising from the fluctuations of low copy number of reactant molecules quite efficiently to perform their job in a robust manner. Network structures may be very crucial in the effective modulation of fluctuation effects. We investigate the interplay between the network structure and the noise behavior in signal transduction networks using Stochastic simulations. Some of the recurrent modules in biological networks seem to be vital in noise control. We correlate the effect of those modules to the function of the global topology of the network. This may explain why certain class of modules are so ubiquitous in Bio-networks.

  8. [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

  9. 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.

  10. Noise measurements as proxies for traffic parameters in monitoring networks.

    PubMed

    Can, A; Dekoninck, L; Rademaker, M; Van Renterghem, T; De Baets, B; Botteldooren, D

    2011-12-01

    The present research describes how microphones could be used as proxies for traffic parameter measurements for the estimation of airborne pollutant emissions. We consider two distinct measurement campaigns of 7 and 12 days, at two different locations along the urban ring road in Antwerp, Belgium, where sound pressure levels and traffic parameters were measured simultaneously. Noise indicators are calculated and used to construct models to estimate traffic parameters. It is found that relying on different statistical levels and selecting specific sound frequencies permits an accurate estimation of traffic intensities and mean vehicle speeds, both for light and heavy vehicles. Estimations of R(2) values ranging between 0.81 and 0.92 are obtained, depending on the location and traffic parameters. Furthermore, the usefulness of these estimated traffic parameters in a monitoring strategy is assessed. Carbon monoxide, hydrocarbon and nitrogen oxide emissions are calculated with the airborne pollutant emission model Artemis. The Artemis outputs fed with directly measured and estimated traffic parameters (based on noise measurements) are very similar. Finally, a method is proposed to enable using a model calibrated at one location at another location without the need for new calibration, making it straightforward to include new measurement locations in a monitoring network. PMID:22000916

  11. 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

  12. 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

  13. Noise in longwall mining

    SciTech Connect

    Antel, J.W.

    1983-03-01

    A series of full-shift noise surveys conducted on longwall sections of six randomly selected coal mines has indicated that the potential exists for 58 percent of the total number of longwall operators surveyed (i.e. shearer operators, headgate and tailgate operators) to be overexposed according to limits set forth in the Code of Federal Regulation; Title 30, Subpart F, Part 70.510. A breakdown by occupation shows that 50 percent of the headgate operators surveyed and 67 percent of the shearer operators surveyed potentially failed to comply with the noise standards.

  14. Rocket Noise Prediction Program

    NASA Technical Reports Server (NTRS)

    Margasahayam, Ravi; Caimi, Raoul

    1999-01-01

    A comprehensive, automated, and user-friendly software program was developed to predict the noise and ignition over-pressure environment generated during the launch of a rocket. The software allows for interactive modification of various parameters affecting the generated noise environment. Predictions can be made for different launch scenarios and a variety of vehicle and launch mount configurations. Moreover, predictions can be made for both near-field and far-field locations on the ground and any position on the vehicle. Multiple engine and fuel combinations can be addressed, and duct geometry can be incorporated efficiently. Applications in structural design are addressed.

  15. Ancient noise generators

    NASA Astrophysics Data System (ADS)

    Beristain, Sergio; Menchaca, Rolando; Velazquez, Roberto

    2002-11-01

    There has been found a whole family of similar artifacts which produce singing noises. These noises sometimes resemble those sounds generated by some animals and/or naturally produced by strong winds passing through holes and edges. It means that these sounds have wide frequency spectrums and very often some clear tones are identified. The original purpose of these artifacts is unknown, but some researchers think that some were used in mortuary ceremonies and employed by H-men. The Olmecan whistle previously presented belongs to this family, and now it is compared with a bone or wooden instrument shown in the Florentine codex.

  16. 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. PMID:25481663

  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. AM noise impact on low level phase noise measurements.

    PubMed

    Cibiel, Gilles; Régis, Myrianne; Tournier, Eric; Llopis, Oliver

    2002-06-01

    The influence of the source AM noise in microwave residual phase noise experiments is investigated. The noise floor degradation problem, caused by the parasitic detection of this type of noise by an unperfectly balanced mixer, is solved thanks to a refinement of the quadrature condition. The parasitic noise contribution attributable to the AM to PM (phase modulation) conversion occurring in the device under test is minimized through the development of a dedicated microwave source featuring an AM noise level as low as -170 dBc/Hz at 10 kHz offset from a 3.5 GHz carrier. PMID:12075970

  19. 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

  20. 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.

  1. 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).

  2. 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.

  3. Satellite orbit determination from an airborne platform

    NASA Astrophysics Data System (ADS)

    Shepard, M. M.; Foshee, J. J.

    This paper describes the requirements, approach, and problems associated with autonomous satellite orbit determination from an airborne platform. The ability to perform orbit determination from an airborne platform removes the reliance on ground control facilities. Aircraft orbit determination offers a more robust system in that it is less susceptible to direct attack, sabotage, or nuclear disaster. Ranging on a satellite and the processing of range/range-rate data along with INS inputs to produce a set of orbital parameters to be transmitted to user terminals are discussed. Several algorithms that could be utilized by the user terminal to recover the satellite position/velocity data from the transmitted message are presented. The ability to compress the ephemeris message to a small size while remaining autonomous for a long period of time, as would be needed in future military communication satellites, is discussed.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Airborne source localization in shallow water

    NASA Astrophysics Data System (ADS)

    Peng, Zhaohui; Wang, Guangxu

    2012-11-01

    Owing to the great difference of acoustic characteristic impedance between air and water, the sound transmission loss from an airborne source into water is very high. So, it is very difficult to do experimental research on air-to-water sound propagation. An experiment was conducted for air-to-water sound propagation in the South China Sea in 2010. A HLA placed on the sea bottom was used to receive signals sent by a high-power loudspeaker hung on a research ship floating 1km to 4km away from the HLA. The locations of airborne sources are estimated from the signals measured by the HLA. The estimated DOA and ranges are in agreement with the GPS records.

  9. 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.

  10. 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.

  11. 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.

  12. Wideband radar for airborne minefield detection

    NASA Astrophysics Data System (ADS)

    Clark, William W.; Burns, Brian; Dorff, Gary; Plasky, Brian; Moussally, George; Soumekh, Mehrdad

    2006-05-01

    Ground Penetrating Radar (GPR) has been applied for several years to the problem of detecting both antipersonnel and anti-tank landmines. RDECOM CERDEC NVESD is developing an airborne wideband GPR sensor for the detection of minefields including surface and buried mines. In this paper, we describe the as-built system, data and image processing techniques to generate imagery, and current issues with this type of radar. Further, we will display images from a recent field test.

  13. A new tool for sampling airborne isocyanates

    SciTech Connect

    Sesana, G.; Nano, G.; Baj, A. )

    1991-05-01

    A new sampling system is presented that uses solid sorbent media contained in a tube for the determination of airborne isocyanates (2.4-2.6 toluene diisocyanate, hexamethylene diisocyanate, and 4.4' diaminodiphenylmethane diisocyanate). The method is compared with the National Institute for Occupational Safety and Health (NIOSH) Method P CAM 5505 (Revision {number sign}1). Experimental tests yielded results that were highly concordant with the NIOSH method.

  14. First airborne pathogen direct analysis system.

    PubMed

    Liu, Qi; Zhang, Yuxiao; Jing, Wenwen; Liu, Sixiu; Zhang, Dawei; Sui, Guodong

    2016-03-01

    We report a portable "sample to answer" system for the rapid detection of airborne pathogens for the first time. The system contains a key microfluidic chip which fulfills both pathogen enrichment and biological identification functions. The system realizes simple operation and less human intervention as well as minimum reagent contamination. The operation is user-friendly and suitable for field and point-of-care applications. The system is capable of handling detection of different pathogens by changing the primers. PMID:26854120

  15. Airborne Visible/Infrared Imaging Spectrometer (AVIRIS)

    NASA Technical Reports Server (NTRS)

    Macenka, Steven A.; Chrisp, Michael P.

    1988-01-01

    The development of the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) has been completed at JPL. This paper outlines the functional requirements of the spectrometer optics subsystem, and describes the spectrometer optical design. The optical subsystem performance is shown in terms of spectral modulation transfer functions, radial energy distributions, and system transmission at selected wavelengths for the four spectrometers. An outline of the spectrometer alignment is included.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Analysis of visual perception of light emitting diode brightness in dense fog with various droplet sizes

    NASA Astrophysics Data System (ADS)

    Kurniawan, Bobsy Arief; Nakashima, Yoshio; Takamatsu, Mamoru

    2008-05-01

    Road signs must provide a conspicuous signal to a wide variety of drivers over a broad range of environmental and geometric conditions. Recently, there are an increasing number of applications in which light emitting diodes (LEDs) are used as the light source, including critical transportation signaling. In the presence of fog, the resulting visual signal is disturbed due to light scattering by airborne water droplets. By measuring LED brightness with human spectral sensitivity in various densities and various droplet sizes (10, 30, 50, and 100 μm), it is understood that the particle size distribution (fog droplet size) and density of fog does affect visibility in fog. The colored LEDs that contain a yellow component had high brightness evaluation, blue component had low brightness evaluation in all densities and different droplet sizes. The result in this paper can contribute to air and land traffic safety and the prevention of accidents.