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Sample records for continuum intensity distribution

  1. Imaging of spatial distributions of the millimeter wave intensity by using visible continuum radiation from a discharge in a Cs–Xe mixture. Part I: Review of the method and its fundamentals

    NASA Astrophysics Data System (ADS)

    Gitlin, M. S.

    2017-02-01

    The first part of the review is presented which is dedicated to the time-resolved method of imaging and measuring the spatial distribution of the intensity of millimeter waves by using visible continuum (VC) emitted by the positive column (PC) of a dc discharge in a mixture of cesium vapor with xenon. The review focuses on the operating principles, fundamentals, and applications of this new technique. The design of the discharge tube and experimental setup used to create a wide homogeneous plasma slab with the help of the Cs-Xe discharge at a gas pressure of 45 Torr are described. The millimeter-wave effects on the plasma slab are studied experimentally. The mechanism of microwave-induced variations in the VC brightness and the causes of violation of the local relation between the VC brightness and the intensity of millimeter waves are discussed. Experiments on the imaging of the field patterns of horn antennas and quasi-optical beams demonstrate that this technique can be used for good-quality imaging of millimeter-wave beams in the entire millimeter-wavelength band. The method has a microsecond temporal resolution and a spatial resolution of about 2 mm. Energy sensitivities of about 10 μJ/cm2 in the Ka-band and about 200 μJ/cm2 in the D-band have been demonstrated.

  2. Imaging of spatial distributions of the millimeter wave intensity by using the Visible Continuum Radiation from a discharge in a Cs-Xe mixture. Part II: Demonstration of application capabilities of the technique

    NASA Astrophysics Data System (ADS)

    Gitlin, M. S.; Glyavin, M. Yu.; Fedotov, A. E.; Tsvetkov, A. I.

    2017-07-01

    The paper presents the second part of the review on a high-sensitive technique for time-resolved imaging and measurements of the 2D intensity profiles of millimeter-wave radiation by means of Visible Continuum Radiation emitted by the positive column of a medium-pressure Cs-Xe DC Discharge (VCRD method). The first part of the review was focused on the operating principles and fundamentals of this new technique [Plasma Phys. Rep. 43, 253 (2017)]. The second part of the review focuses on experiments demonstrating application of this imaging technique to measure the parameters of radiation at the output of moderate-power millimeter-wave sources. In particular, the output waveguide mode of a moderate-power W-band gyrotron with a pulsed magnetic field was identified and the relative powers of some spurious modes at the outputs of this gyrotron and a pulsed D-band orotron were evaluated. The paper also reviews applications of the VCRD technique for real-time imaging and nondestructive testing with a frame rate of higher than 10 fps by using millimeter waves. Shadow projection images of objects opaque and transparent for millimeter waves have been obtained using pulsed watt-scale millimeter waves for object illumination. Near video frame rate millimeter-wave shadowgraphy has been demonstrated. It is shown that this technique can be used for single-shot screening (including detection of concealed objects) and time-resolved imaging of time-dependent processes.

  3. Distributions of self-trapped hole continuums in silica glass

    SciTech Connect

    Wang, R. P.; Saito, K.; Ikushima, A. J.

    2006-07-01

    Photobleaching of self-trapped holes (STH) in low temperature UV-irradiated silica glass has been investigated by the electron spin resonance method. The bleaching time dependence of the decay of two kinds of STH, STH{sub 1}, and STH{sub 2}, could be well fitted by the stretched exponential function, and STH{sub 2} has a quicker decay than STH{sub 1}. On the other hand, the decay becomes significant large when the photon energy increases from 1.5 to 2.0 eV, and then keeps constant with a further increase of photon energy. The distributions of the STH continuums are estimated at the positions on top of the valence band, being 1.66{+-}0.27 eV for STH{sub 1} and 1.63{+-}0.33 eV for STH{sub 2}. A possible recombination mechanism is proposed to explain the decay of STH signals.

  4. The continuum intensity as a function of magnetic field. II. Local magnetic flux and convective flows

    NASA Astrophysics Data System (ADS)

    Kobel, P.; Solanki, S. K.; Borrero, J. M.

    2012-06-01

    Context. To deepen our understanding of the role of small-scale magnetic fields in active regions (ARs) and in the quiet Sun (QS) on the solar irradiance, it is fundamental to investigate the physical processes underlying their continuum brightness. Previous results showed that magnetic elements in the QS reach larger continuum intensities than in ARs at disk center, but left this difference unexplained. Aims: We use Hinode/SP disk center data to study the influence of the local amount of magnetic flux on the vigour of the convective flows and the continuum intensity contrasts. Methods: The apparent (i.e. averaged over a pixel) longitudinal field strength and line-of-sight (LOS) plasma velocity were retrieved by means of Milne-Eddington inversions (VFISV code). We analyzed a series of boxes taken over AR plages and the QS, to determine how the continuum intensity contrast of magnetic elements, the amplitude of the vertical flows and the box-averaged contrast were affected by the mean longitudinal field strength in the box (which scales with the total unsigned flux in the box). Results: Both the continuum brightness of the magnetic elements and the dispersion of the LOS velocities anti-correlate with the mean longitudinal field strength. This can be attributed to the "magnetic patches" (here defined as areas where the longitudinal field strength is above 100 G) carrying most of the flux in the boxes. There the velocity amplitude and the spatial scale of convection are reduced. Due to this hampered convective transport, these patches appear darker than their surroundings. Consequently, the average brightness of a box decreases as the the patches occupy a larger fraction of it and the amount of embedded flux thereby increases. Conclusions: Our results suggest that as the magnetic flux increases locally (e.g. from weak network to strong plage), the heating of the magnetic elements is reduced by the intermediate of a more suppressed convective energy transport within

  5. The relationship between the carbon monoxide intensity and the radio continuum emission in spiral galaxies

    NASA Technical Reports Server (NTRS)

    Adler, David S.; Lo, K. Y.; Allen, Ronald J.

    1991-01-01

    The relationship between the velocity-integrated CO emission and the nonthermal radio continuum brightness in the disks of normal spiral galaxies is examined on a variety of length scales. On a global scale, the total CO intensity correlates strongly with the total radio continuum flux density for a sample of 31 galaxies. On scales of about 2 kpc or more in the disk of individual galaxies, it is found that the ratio I(CO)/T(20) remains fairly constant over the entire disk as well as from galaxy to galaxy. For the eight spirals in the sample, the disk-averaged values of I(CO)/T(20) range from 0.6-2.4, with the average over all eight galaxies being 1.3 +/- 0.6. It is concluded that what these various length scales actually trace are differences in the primary heating mechanism of the gas in the beam. The observed relationship between CO and nonthermal radio continuum emission can be explained by assuming that molecular gas in galactic disks is heated primarily by cosmic rays. The observed relationship is used to show that the brightness of synchrotron emission is proportional to n(cr) exp 0.4 - 0.9 in galactic disks.

  6. The spatial distribution of ultraviolet line and continuum emission in Herbig-Haro objects

    NASA Technical Reports Server (NTRS)

    Lee, M. G.; Boehm, K. H.; Temple, S. D.; Raga, A. C.; Mateo, M. L.

    1988-01-01

    Archival IUE data and monochromatic CCD images in the optical range are used to compare the spatial distribution of UV and optical emission in HH 1, HH 2, HH 24, HH 32, HH 43, and HH 47. For all six objects, the observed UV radiation is shown to originate in the objects themselves. The results indicate that the C IV and semiforbidden emission-line regions are small. Although the continuum in the IUE short-wavelength range displays a distribution that is broader than that of any measured line emission in the UV or optical range, the continuum distribution in the IUE long-wavelength range is quite narrow.

  7. Absolute continuum intensity diagnostics of a novel large coaxial gridded hollow cathode argon plasma

    SciTech Connect

    Gao, Ruilin; Yuan, Chengxun E-mail: zhouzx@hit.edu.cn; Jia, Jieshu; Zhou, Zhong-Xiang E-mail: zhouzx@hit.edu.cn; Wang, Ying; Wang, Xiaoou; Li, Hui; Wu, Jian

    2016-08-15

    This paper reports a novel coaxial gridded hollow discharge during operation at low pressure (20 Pa–80 Pa) in an argon atmosphere. A homogeneous hollow discharge was observed under different conditions, and the excitation mechanism and the discharge parameters for the hollow cathode plasma were examined at length. An optical emission spectrometry (OES) method, with a special focus on absolute continuum intensity method, was employed to measure the plasma parameters. The Langmuir probe measurement (LPM) was used to verify the OES results. Both provided electron density values (n{sub e}) in the order of 10{sup 16} m{sup −3} for different plasma settings. Taken together, the results show that the OES method is an effective approach to diagnosing the similar plasma, especially when the LPM is hardly operated.

  8. Impact of drinking water treatment and distribution on the microbiome continuum: an ecological disturbance's perspective.

    PubMed

    Zhang, Ya; Oh, Seungdae; Liu, Wen-Tso

    2017-08-01

    While microbes are known to be present at different stages of a drinking water system, their potential functions and ability to grow in such systems are poorly understood. In this study, we demonstrated that treatment and distribution processes could be viewed as ecological disturbances exhibited over space on the microbiome continuum in a groundwater-derived system. Results from 16S rRNA gene amplicon analysis and metagenomics suggested that disturbances in the system were intense as the community diversity was substantially reduced during the treatment steps. Specifically, syntrophs and methanogens dominant in raw water (RW) disappeared after water abstraction, accompanied by a substantial decrease in both the abundance and number of functional genes related to methanogenesis. The softening effluent was dominated by an Exiguobacterium-related population, likely due to its ability to use the phosphotransferase system (PTS) as regulatory machinery to control the energy conditions of the cell. After disinfection and entering the distribution system, community-level functionality remained relatively stable, whereas the community structure differed from those taken in the treatment steps. The diversity and high abundance of some eukaryotic groups in the system suggested that predation could be a disturbance to the bacterial microbiome, which could further drive the diversification of the bacterial community. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  9. The sky distribution of positronium annihilation continuum emission measured with SPI/INTEGRAL

    NASA Astrophysics Data System (ADS)

    Weidenspointner, G.; Shrader, C. R.; Knödlseder, J.; Jean, P.; Lonjou, V.; Guessoum, N.; Diehl, R.; Gillard, W.; Harris, M. J.; Skinner, G. K.; von Ballmoos, P.; Vedrenne, G.; Roques, J.-P.; Schanne, S.; Sizun, P.; Teegarden, B. J.; Schönfelder, V.; Winkler, C.

    2006-05-01

    We present a measurement of the sky distribution of positronium (Ps) annihilation continuum emission obtained with the SPI spectrometer on board ESA's INTEGRAL observatory. The only sky region from which significant Ps continuum emission is detected is the Galactic bulge. The Ps continuum emission is circularly symmetric about the Galactic centre, with an extension of about 8° FWHM. Within measurement uncertainties, the sky distribution of the Ps continuum emission is consistent with that found by us for the 511 keV electron-positron annihilation line using SPI. Assuming that 511 keV line and Ps continuum emission follow the same spatial distribution, we derive a Ps fraction of 0.92±0.09. These results strengthen our conclusions regarding the origin of positrons in our Galaxy based on observations of the 511 keV line. In particular, they suggest that the main source of Galactic positrons is associated with an old stellar population, such as Type Ia supernovae, classical novae, or low-mass X-ray binaries. Light dark matter is a possible alternative source of positrons.

  10. Scale invariance of continuum size distribution upon irreversible growth of surface islands

    NASA Astrophysics Data System (ADS)

    Dubrovskii, V. G.; Sokolova, Zh. V.

    2015-06-01

    The continuum kinetic equation for irreversible heterogeneous growth of a surface island is ana-lyzed given a special form of the dependence of capture coefficient σ on size s and coverage of the surface Θ. It is shown that, if σ( s, Θ) = α(Θ)( a + s)β, the function α(Θ) is arbitrary, and 0 ≤ β ≤ 1, then the solutions of the continuum equation of the first order satisfy the hypothesis about the scale invariance of the size distribu-tion (scaling) in a single exceptional case—at ≤ = 1. The obtained results testify about the presence of a fun-damental relation of the scaling and linearity of the dependence σ( s). Problems about associations of distri-bution functions in continuum and discrete growth models and about application of the obtained solutions for modeling and interpretation of experimental data in different systems are discussed.

  11. Uncertainties in Properties Calculated from Fitted Potential Functions and Determining Potential Functions from FITS to Bound to Continuum Intensity Data

    NASA Astrophysics Data System (ADS)

    Le Roy, Robert J.

    2013-06-01

    In recent years it has become increasingly common to analyse spectroscopic data by using ``direct potential fits" of simulated data generated from analytic potential energy functions to experiment to optimize the parameters defining that potential energy function. This has the advantages of circumventing use of the semiclassical approximations associated with traditional methodologies, and of directly yielding a closed-form expression that is the most compact and comprehensive way to summarize what we know about a molecule. A question which then arises is: What are the uncertainties in properties computed using this potential? It turns out that this question is very closely related to the question of how to apply this simulation/fitting method efficiently to the analysis of bound to continuum intensity data. Both depend upon being able to answer the question: What are the partial derivatives of a wavefunction with respect to the parameters defining the potential energy function from which it is generated? It will be shown that such partial derivatives may be obtained readily as the `particular' solutions of linear inhomogeneous differential equations of a type that is routinely solved in another context for calculating the centrifugal distortion constants of diatomic molecules. Applications of this technique have been incorporated into the publicly available bound-state data analysis and simulation program DPotFit and the distributed bound to continuum simulation/fitting program BCONT. J.M. Hutson, J. Phys. B (At. Mol. Phys) {14}, 851 (1981). J. Tellinghuisen, J. Mol. Spectrosc. {122}, 455 (1987). See http://leroy.uwaterloo.ca/programs/

  12. Spectrophotometry of Wolf-Rayet stars. I - Continuum energy distributions

    NASA Technical Reports Server (NTRS)

    Morris, Patrick W.; Brownsberger, Kenneth R.; Conti, Peter S.; Massey, Philip; Vacca, William D.

    1993-01-01

    All available low-resolution IUE spectra are assembled for Galactic, LMC, and SMC W-R stars and are merged with ground-based optical and NIR spectra in order to collate in a systematic fashion the shapes of these energy distributions over the wavelength range 0.1-1 micron. They can be consistently fitted by a power law of the form F(lambda) is approximately equal to lambda exp -alpha over the range 1500-9000 A to derive color excesses E(B-V) and spectral indices by removing the 2175-A interstellar absorption feature. The WN star color excesses derived are found to be in good agreement with those of Schmutz and Vacca (1991) and Koesterke et al. (1991). Significant heterogeneity in spectral index values was generally seen with any given subtype, but the groups consisting of the combined set of Galactic and LMC W-R stars, the separate WN and WC sequences, and the Galactic and LMC W-R stars all showed a striking and consistent Gaussian-like frequency distribution of values.

  13. Spectrophotometry of Wolf-Rayet stars. I - Continuum energy distributions

    NASA Technical Reports Server (NTRS)

    Morris, Patrick W.; Brownsberger, Kenneth R.; Conti, Peter S.; Massey, Philip; Vacca, William D.

    1993-01-01

    All available low-resolution IUE spectra are assembled for Galactic, LMC, and SMC W-R stars and are merged with ground-based optical and NIR spectra in order to collate in a systematic fashion the shapes of these energy distributions over the wavelength range 0.1-1 micron. They can be consistently fitted by a power law of the form F(lambda) is approximately equal to lambda exp -alpha over the range 1500-9000 A to derive color excesses E(B-V) and spectral indices by removing the 2175-A interstellar absorption feature. The WN star color excesses derived are found to be in good agreement with those of Schmutz and Vacca (1991) and Koesterke et al. (1991). Significant heterogeneity in spectral index values was generally seen with any given subtype, but the groups consisting of the combined set of Galactic and LMC W-R stars, the separate WN and WC sequences, and the Galactic and LMC W-R stars all showed a striking and consistent Gaussian-like frequency distribution of values.

  14. Insights from probability distribution functions of intensity maps

    NASA Astrophysics Data System (ADS)

    Breysse, Patrick C.; Kovetz, Ely D.; Behroozi, Peter S.; Dai, Liang; Kamionkowski, Marc

    2017-05-01

    In the next few years, intensity-mapping surveys that target lines such as CO, Lyα and C ii stand to provide powerful probes of high-redshift astrophysics. However, these line emissions are highly non-Gaussian, and so the typical power-spectrum methods used to study these maps will leave out a significant amount of information. We propose a new statistic, the probability distribution of voxel intensities, which can access this extra information. Using a model of a CO intensity map at z ˜ 3 as an example, we demonstrate that this voxel intensity distribution (VID) provides substantial constraining power beyond what is obtainable from the power spectrum alone. We find that a future survey is similar to the planned CO Mapping Array Pathfinder (COMAP). Full experiment could constrain the CO luminosity function to the order of ˜10 per cent. We also explore the effects of contamination from continuum emission, interloper lines and gravitational lensing on our constraints and find that the VID statistic retains significant constraining power even in pessimistic scenarios.

  15. Aspects of disordered eating continuum in elite high-intensity sports.

    PubMed

    Sundgot-Borgen, J; Torstveit, M K

    2010-10-01

    Dieting is an important risk factor for disordered eating and eating disorders. Disordered eating occurs on a continuum from dieting and restrictive eating, abnormal eating behavior, and finally clinical eating disorders. The prevalence of eating disorders is increased in elite athletes and for this group the cause of starting to diet is related to (a) perception of the paradigm of appearance in the specific sport, (b) perceived performance improvements, and (c) sociocultural pressures for thinness or an "ideal" body. Athletes most at risk for disordered eating are those involved in sports emphasizing a thin body size/shape, a high power-to-weight ratio, and/or sports utilizing weight categories, such as in some high-intensity sports. In addition to dieting, personality factors, pressure to lose weight, frequent weight cycling, early start of sport-specific training, overtraining, injuries, and unfortunate coaching behavior, are important risk factors. To prevent disordered eating and eating disorders, the athletes have to practice healthy eating, and the medical staff of teams and parents must be able to recognize symptoms indicating risk for eating disorders. Coaches and leaders must accept that disordered eating can be a problem in the athletic community and that openness regarding this challenge is important. © 2010 John Wiley & Sons A/S.

  16. Statistical modeling of tornado intensity distributions

    NASA Astrophysics Data System (ADS)

    Dotzek, Nikolai; Grieser, Jürgen; Brooks, Harold E.

    We address the issue to determine an appropriate general functional shape of observed tornado intensity distributions. Recently, it was suggested that in the limit of long and large tornado records, exponential distributions over all positive Fujita or TORRO scale classes would result. Yet, our analysis shows that even for large databases observations contradict the validity of exponential distributions for weak (F0) and violent (F5) tornadoes. We show that observed tornado intensities can be much better described by Weibull distributions, for which an exponential remains a special case. Weibull fits in either v or F scale reproduce the observations significantly better than exponentials. In addition, we suggest to apply the original definition of negative intensity scales down to F-2 and T-4 (corresponding to v=0 m s -1) at least for climatological analyses. Weibull distributions allow for an improved risk assessment of violent tornadoes up to F6, and better estimates of total tornado occurrence, degree of underreporting and existence of subcritical tornadic circulations below damaging intensity. Therefore, our results are relevant for climatologists and risk assessment managers alike.

  17. Modification of the photoelectron angular distribution through laser-induced continuum structure

    SciTech Connect

    Nakajima, Takashi; Buica, Gabriela

    2005-01-01

    We theoretically investigate how the photoelectron angular distribution is altered by the introduction of a dressing laser. The physical mechanism underlying this alteration is the so-called laser-induced continuum structure; namely, a strong dressing laser induces quantum mechanical interference, the degree of which is different for different ionization channels. Therefore the branching ratio into different ionization channels changes as a function of laser detuning, and accordingly the photoelectron angular distribution is altered. After a general argument, we present specific theoretical results for the K atom, which indeed exhibit significant modification of the photoelectron angular distribution.

  18. Measuring the entry distribution and the quasi-continuum of γ rays with tracking arrays

    NASA Astrophysics Data System (ADS)

    Lauritsen, T.; Korichi, A.; Khoo, T. L.; Carpenter, M. P.; Janssens, R. V. F.; Riley, L. A.; Seweryniak, D.; Zhu, S.

    2017-07-01

    With the advent of γ-ray tracking detector arrays, it should be possible to measure entry distributions and the quasi-continuum of γ rays with better accuracy than was possible with the previous generation of escape—suppressed detector arrays. However, the techniques for doing so may represent more of a challenge for these new tracking arrays. Here, the techniques developed recently are being presented.

  19. Continuum Generation of the Third-Harmonic Pulse Generated by an Intense Femtosecond IR Laser Pulse in Air

    DTIC Science & Technology

    2003-06-06

    c.m. bowden3 Continuum generation of the third-harmonic pulse generated by an intense femtosecond IR laser pulse in air 1 Time Domain Corporation...picosecond high-peak-power laser pulses are propagated in air. The supercontinuum generated during the filamentation process has been used for time ...collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources

  20. Intensity distributions of gamma-ray bursts

    SciTech Connect

    Band, D. L.

    2001-01-01

    Observations of individual bursts chosen by the vagaries of telescope availability demonstrated that bursts are not standard candles and that their apparent energy can be as great as 10{sup 54} erg. However, determining the distribution of their apparent energy (and of other burst properties) requires the statistical analysis of a well-defined burst sample; the sample definition includes the threshold for including a burst in the sample. Thus optical groups need to the criteria behind the decision to search for a spectroscopic redshift. Currently the burst samples are insufficient to choose between lognormal and power law functional forms of the distribution, and the parameter values for these functional forms differ between burst samples. Similarly, the actual intensity distribution may be broader than observed, with a low energy tail extending below the detection threshold.

  1. A continuum breakdown parameter based on the characteristic function of the molecular velocity distribution

    NASA Astrophysics Data System (ADS)

    Alamatsaz, Arghavan; Venkattraman, Ayyaswamy

    2014-11-01

    Rarefied flows characterized by Knudsen numbers (Kn) greater than 0.1 are frequently encountered in several applications including low-pressure, high speed and microscale flows and require computationally expensive molecular approaches such as direct simulation Monte Carlo (DSMC) to accurately capture the physical phenomena unique to these flows. However, most of these flows also contain regions where traditional inexpensive continuum techniques such as the Navier-Stokes (NS) equations are sufficiently accurate making a hybrid NS-DSMC approach attractive and optimal. Such a hybrid method typically requires a robust continuum breakdown parameter (CBP) to determine regions where each method should be applied. Historically, hybrid methods have used CBPs based on the macroscopic properties which are lower order moments of the molecular velocity distribution function (VDF) and their gradients which can have significant inaccuracies. In this work, we propose a novel CBP that utilizes all moments of the VDF by computing the characteristic function with limited computational overhead. We also compare the performance of this CBP using standard benchmark problems including structure of a normal shock wave and Fourier-Couette flow for various Kn from continuum to free-molecular.

  2. The probability distribution of intense daily precipitation

    NASA Astrophysics Data System (ADS)

    Cavanaugh, Nicholas R.; Gershunov, Alexander; Panorska, Anna K.; Kozubowski, Tomasz J.

    2015-03-01

    The probability tail structure of over 22,000 weather stations globally is examined in order to identify the physically and mathematically consistent distribution type for modeling the probability of intense daily precipitation and extremes. Results indicate that when aggregating data annually, most locations are to be considered heavy tailed with statistical significance. When aggregating data by season, it becomes evident that the thickness of the probability tail is related to the variability in precipitation causing events and thus that the fundamental cause of precipitation volatility is weather diversity. These results have both theoretical and practical implications for the modeling of high-frequency climate variability worldwide.

  3. GBM TGF Pulse Properties and Intensity Distribution

    NASA Astrophysics Data System (ADS)

    Briggs, M. S.; Foley, S.; Tierney, D.; Fitzpatrick, G.; Chaplin, V.; McBreen, S.; Connaughton, V.

    2013-12-01

    We report refined analyses of TGFs detected by the Gamma-ray Burst Monitor (GBM) instrument onboard Fermi. Of a sample of ~300 bright TGFs that triggered GBM, 19% are found to have multiple pulses. The individual pulses can be either be symmetric or asymmetric and are well fit with Gaussian or log-normal functions. Compton tails appear to explain some but not all asymmetric pulses. Using a sample of ~100 TGFs we obtain the fluence distribution in a model independent manner, correcting for detection efficiency, deadtime and pulse pileup. Detection effiency causes GBM not to detect some faint TGFs while deadtime and pulse pileup cause the intensities of TGFs to be underestimated. The corrected fluence distribution is well fit with a power-law of index -2.20 +/- 0.13.

  4. CONTINUUM INTENSITY AND [O i] SPECTRAL LINE PROFILES IN SOLAR 3D PHOTOSPHERIC MODELS: THE EFFECT OF MAGNETIC FIELDS

    SciTech Connect

    Fabbian, D.; Moreno-Insertis, F. E-mail: fmi@iac.es

    2015-04-01

    The importance of magnetic fields in three-dimensional (3D) magnetoconvection models of the Sun’s photosphere is investigated in terms of their influence on the continuum intensity at different viewing inclination angles and on the intensity profile of two [O i] spectral lines. We use the RH numerical radiative transfer code to perform a posteriori spectral synthesis on the same time series of magnetoconvection models used in our publications on the effect of magnetic fields on abundance determination. We obtain a good match of the synthetic disk-center continuum intensity to the absolute continuum values from the Fourier Transform Spectrometer (FTS) observational spectrum; the match of the center-to-limb variation synthetic data to observations is also good, thanks, in part, to the 3D radiation transfer capabilities of the RH code. The different levels of magnetic flux in the numerical time series do not modify the quality of the match. Concerning the targeted [O i] spectral lines, we find, instead, that magnetic fields lead to nonnegligible changes in the synthetic spectrum, with larger average magnetic flux causing both of the lines to become noticeably weaker. The photospheric oxygen abundance that one would derive if instead using nonmagnetic numerical models would thus be lower by a few to several centidex. The inclusion of magnetic fields is confirmed to be important for improving the current modeling of the Sun, here in particular in terms of spectral line formation and of deriving consistent chemical abundances. These results may shed further light on the still controversial issue regarding the precise value of the solar oxygen abundance.

  5. Effects of laser polarization on photoelectron angular distribution through laser-induced continuum structure

    SciTech Connect

    Buica, Gabriela; Nakajima, Takashi

    2005-11-15

    We theoretically investigate the effects of laser polarization on the photoelectron angular distribution through laser-induced continuum structure. We focus on a polarization geometry where the probe and dressing lasers are both linearly polarized and change the relative polarization angle between them. We find that the total ionization yield and the branching ratio into different ionization channels change as a function of the relative polarization angle, and accordingly the photoelectron angular distribution is altered. We present specific results for the 4p{sub 1/2}-6p{sub 1/2} and 4p{sub 3/2}-6p{sub 3/2} systems of the K atom and show that the change of the polarization angle leads to a significant modification of the photoelectron angular distribution.

  6. 14 CFR 27.1389 - Position light distribution and intensities.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Position light distribution and intensities... light distribution and intensities. (a) General. the intensities prescribed in this section must be provided by new equipment with light covers and color filters in place. Intensities must be determined...

  7. 14 CFR 29.1389 - Position light distribution and intensities.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Position light distribution and intensities... Position light distribution and intensities. (a) General. The intensities prescribed in this section must be provided by new equipment with light covers and color filters in place. Intensities must...

  8. 14 CFR 29.1389 - Position light distribution and intensities.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Position light distribution and intensities... Position light distribution and intensities. (a) General. The intensities prescribed in this section must be provided by new equipment with light covers and color filters in place. Intensities must...

  9. 14 CFR 27.1389 - Position light distribution and intensities.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Position light distribution and intensities... light distribution and intensities. (a) General. the intensities prescribed in this section must be provided by new equipment with light covers and color filters in place. Intensities must be determined...

  10. 14 CFR 29.1389 - Position light distribution and intensities.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Position light distribution and intensities... Position light distribution and intensities. (a) General. The intensities prescribed in this section must be provided by new equipment with light covers and color filters in place. Intensities must...

  11. 14 CFR 29.1389 - Position light distribution and intensities.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Position light distribution and intensities... Position light distribution and intensities. (a) General. The intensities prescribed in this section must be provided by new equipment with light covers and color filters in place. Intensities must...

  12. 14 CFR 27.1389 - Position light distribution and intensities.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Position light distribution and intensities... light distribution and intensities. (a) General. the intensities prescribed in this section must be provided by new equipment with light covers and color filters in place. Intensities must be determined...

  13. 14 CFR 27.1389 - Position light distribution and intensities.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Position light distribution and intensities... light distribution and intensities. (a) General. the intensities prescribed in this section must be provided by new equipment with light covers and color filters in place. Intensities must be determined...

  14. Center-to-limb variation of intensity and polarization in continuum spectra of FGK stars for spherical atmospheres

    NASA Astrophysics Data System (ADS)

    Kostogryz, N. M.; Milic, I.; Berdyugina, S. V.; Hauschildt, P. H.

    2016-02-01

    Aims: One of the necessary parameters needed for the interpretation of the light curves of transiting exoplanets or eclipsing binary stars (as well as interferometric measurements of a star or microlensing events) is how the intensity and polarization of light changes from the center to the limb of a star. Scattering and absorption processes in the stellar atmosphere affect both the center-to-limb variation of intensity (CLVI) and polarization (CLVP). In this paper, we present a study of the CLVI and CLVP in continuum spectra, taking into consideration the different contributions of scattering and absorption opacity for a variety of spectral type stars with spherical atmospheres. Methods: We solve the radiative transfer equation for polarized light in the presence of a continuum scattering, taking into consideration the spherical model of a stellar atmosphere. To cross-check our results, we developed two independent codes that are based on Feautrier and short characteristics methods, respectively, Results: We calculate the center-to-limb variation of intensity (CLVI) and polarization (CLVP) in continuum for the Phoenix grid of spherical stellar model atmospheres for a range of effective temperatures (4000-7000 K), gravities (log g = 1.0-5.5), and wavelengths (4000-7000 Å), which are tabulated and available at the CDS. In addition, we present several tests of our codes and compare our calculations for the solar atmosphere with published photometric and polarimetric measurements. We also show that our two codes provide similar results in all considered cases. Conclusions: For sub-giant and dwarf stars (log g = 3.0-4.5), the lower gravity and lower effective temperature of a star lead to higher limb polarization of the star. For giant and supergiant stars (log g = 1.0-2.5), the highest effective temperature yields the largest polarization. By decreasing the effective temperature of a star down to 4500-5500 K (depending on log g), the limb polarization decreases and

  15. Continuum kinetic methods for analyzing wave physics and distribution function dynamics in the turbulence dissipation challenge

    NASA Astrophysics Data System (ADS)

    Juno, J.; Hakim, A.; TenBarge, J.; Dorland, W.

    2015-12-01

    We present for the first time results for the turbulence dissipation challenge, with specific focus on the linear wave portion of the challenge, using a variety of continuum kinetic models: hybrid Vlasov-Maxwell, gyrokinetic, and full Vlasov-Maxwell. As one of the goals of the wave problem as it is outlined is to identify how well various models capture linear physics, we compare our results to linear Vlasov and gyrokinetic theory. Preliminary gyrokinetic results match linear theory extremely well due to the geometry of the problem, which eliminates the dominant nonlinearity. With the non-reduced models, we explore how the subdominant nonlinearities manifest and affect the evolution of the turbulence and the energy budget. We also take advantage of employing continuum methods to study the dynamics of the distribution function, with particular emphasis on the full Vlasov results where a basic collision operator has been implemented. As the community prepares for the next stage of the turbulence dissipation challenge, where we hope to do large 3D simulations to inform the next generation of observational missions such as THOR (Turbulence Heating ObserveR), we argue for the consideration of hybrid Vlasov and full Vlasov as candidate models for these critical simulations. With the use of modern numerical algorithms, we demonstrate the competitiveness of our code with traditional particle-in-cell algorithms, with a clear plan for continued improvements and optimizations to further strengthen the code's viability as an option for the next stage of the challenge.

  16. Global Distributions of Thunderstorms, Segregated by Intensity

    NASA Astrophysics Data System (ADS)

    Cecil, D. J.

    2006-12-01

    geographical locations of intense thunderstorms demonstrate strong regional preferences for certain land areas, while they are extremely rare over tropical oceans. Favored locations include south central United States, southeast South America, and equatorial Africa. There is a preference for these to occur in the spring and summer, but they do occur throughout most of the year. Other regions have extreme storms more tightly confined to specific seasons, such as the Sahel, the Indian subcontinent, and northern Australia. Intense storms are distributed quite differently than rainfall, and even differently than total annual lightning. Maps of these provide some new metrics for global models, if they are to simulate the type of convection as a component of our climate system.

  17. Photoion rotational distributions from near-threshold to deep in the continuum

    NASA Astrophysics Data System (ADS)

    Poliakoff, E. D.; Choi, Heung Cheun; Rao, R. M.; Mihill, A. G.; Kakar, Sandeep; Wang, Kwanghsi; McKoy, V.

    1995-08-01

    We present the first measurements of ion rotational distributions for photoionization over an extended range [0≤EK≤200 eV for N2 (2σ-1u) and 3≤EK≤125 eV for CO (4σ-1)]. The N2 ion rotational distributions are seen to change dramatically over this energy range, indicating that characteristically molecular behavior of the photoelectron persists far from ionization threshold. In addition, the N2 and CO results show a strikingly different dependence on energy. Although differences are expected due to the absence of a center of symmetry in CO, detailed calculations reveal that this behavior arises from the presence of Cooper minima in the 2σu→kσg continuum in the case of N2 and from an f-wave shape resonance in the 4σ→kσ channel in CO. Agreement between measured and calculated ion rotational distributions is excellent. The N2 results are also compared with electron bombardment ionization data. This comparison demonstrates that previous interpretations of electron bombardment data are prone to errors.

  18. Mammographic resolution: influence of focal spot intensity distribution and geometry.

    PubMed

    Nickoloff, E L; Donnelly, E; Eve, L; Atherton, J V; Asch, T

    1990-01-01

    The influence of focal spot intensity distribution and geometry upon mammographic image quality were evaluated. The modulation transfer functions (MTF's) for eight different intensity distributions were determined and plotted in a manner to eliminate the effects of magnification and focal spot dimension. The results indicated that the total cross-sectional area is important for focal spots with uniform intensity distributions and equivalent diameters. For equivalent focal spot dimensions, intensity distributions with edge bands were shown to have less spatial resolution than uniform intensity distributions. Focal spots with greater intensities towards their centers provided better resolution than either uniform intensity distributions or distributions with edge bands for equivalent sizes. The type of intensity distribution was also shown to affect the accuracy of star pattern measurements of focal spot size; this method of measurement is only precise for a uniform square intensity distribution. Errors obtained with several other intensity distributions were tabulated. The variations of the effective focal spot size with position along the anode-cathode axis were shown to be of a factor of approximately two to three. The combined effects of geometric blur and film/screen blur were present for various heights above the cassette tray on several different mammographic systems.

  19. Disparities in the Population Distribution of African American and Non-Hispanic White Smokers along the Quitting Continuum

    ERIC Educational Resources Information Center

    Trinidad, Dennis R.; Xie, Bin; Fagan, Pebbles; Pulvers, Kim; Romero, Devan R.; Blanco, Lyzette; Sakuma, Kari-Lyn K.

    2015-01-01

    Purpose: To examine disparities and changes over time in the population-level distribution of smokers along a cigarette quitting continuum among African American smokers compared with non-Hispanic Whites. Methods: Secondary data analyses of the 1999, 2002, 2005, and 2008 California Tobacco Surveys (CTS). The CTS are large, random-digit-dialed,…

  20. Disparities in the Population Distribution of African American and Non-Hispanic White Smokers along the Quitting Continuum

    ERIC Educational Resources Information Center

    Trinidad, Dennis R.; Xie, Bin; Fagan, Pebbles; Pulvers, Kim; Romero, Devan R.; Blanco, Lyzette; Sakuma, Kari-Lyn K.

    2015-01-01

    Purpose: To examine disparities and changes over time in the population-level distribution of smokers along a cigarette quitting continuum among African American smokers compared with non-Hispanic Whites. Methods: Secondary data analyses of the 1999, 2002, 2005, and 2008 California Tobacco Surveys (CTS). The CTS are large, random-digit-dialed,…

  1. Planck Early Results. XV. Spectral Energy Distributions and Radio Continuum Spectra of Northern Extragalactic Radio Sources

    NASA Technical Reports Server (NTRS)

    Aatrokoski, J.; Ade, P. A. R.; Aghanim, N.; Aller, H. D.; Aller, M. F.; Angelakis, E.; Amaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; hide

    2011-01-01

    Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources. based on the Planck Early Release Compact Source Catalogue (ERCSC) and simultaneous multi frequency data. The nine Planck frequencies, from 30 to 857 GHz, are complemented by a set of simultaneous observations ranging from radio to gamma-rays. This is the first extensive frequency coverage in the radio and millimetre domains for an essentially complete sample of extragalactic radio sources, and it shows how the individual shocks, each in their own phase of development, shape the radio spectra as they move in the relativistic jet. The SEDs presented in this paper were fitted with second and third degree polynomials to estimate the frequencies of the synchrotron and inverse Compton (IC) peaks, and the spectral indices of low and high frequency radio data, including the Planck ERCSC data, were calculated. SED modelling methods are discussed, with an emphasis on proper. physical modelling of the synchrotron bump using multiple components. Planck ERCSC data also suggest that the original accelerated electron energy spectrum could be much harder than commonly thought, with power-law index around 1.5 instead of the canonical 2.5. The implications of this are discussed for the acceleration mechanisms effective in blazar shock. Furthermore in many cases the Planck data indicate that gamma-ray emission must originate in the same shocks that produce the radio emission.

  2. Planck early results. XV. Spectral energy distributions and radio continuum spectra of northern extragalactic radio sources

    DOE PAGES

    Aatrokoski, J.

    2011-12-01

    Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources, based on the Planck Early Release Compact Source Catalogue (ERCSC) and simultaneous multifrequency data. The nine Planck frequencies, from 30 to 857GHz, are complemented by a set of simultaneous observations ranging from radio to gamma-rays. This is the first extensive frequency coverage in the radio and millimetre domains for an essentially complete sample of extragalactic radio sources, and it shows how the individual shocks, each in their own phase of development, shape the radio spectra as they move in the relativisticmore » jet. The SEDs presented in this paper were fitted with second and third degree polynomials to estimate the frequencies of the synchrotron and inverse Compton (IC) peaks, and the spectral indices of low and high frequency radio data, including the Planck ERCSC data, were calculated. SED modelling methods are discussed, with an emphasis on proper, physical modelling of the synchrotron bump using multiple components. Planck ERCSC data also suggest that the original accelerated electron energy spectrum could be much harder than commonly thought, with power-law index around 1.5 instead of the canonical 2.5. The implications of this are discussed for the acceleration mechanisms effective in blazar shock. Furthermore in many cases the Planck data indicate that gamma-ray emission must originate in the same shocks that produce the radio emission.« less

  3. Quantum beat oscillations in the two-color-photoionization continuum of neon and their dependence on the intensity of the ionizing laser pulse

    SciTech Connect

    Geiseler, Henning; Rottke, Horst; Steinmeyer, Guenter; Sandner, Wolfgang

    2011-09-15

    We investigate quantum beat oscillations in the photoionization continuum of Ne atoms that are photoionized by absorption of two photons via a group of excited bound states using ultrashort extreme ultraviolet and infrared laser pulses. The extreme ultraviolet pulse starts an excited-state wave packet that is photoionized by a high-intensity infrared pulse after a variable time delay. We analyze the continuum quantum beats from this two-step photoionization process and their dependence on the photoelectron kinetic energy. We find a pronounced dependence of the quantum beat amplitudes on the photoelectron kinetic energy. The dependence changes significantly with the applied infrared laser-pulse intensity. The experimental results are in good qualitative agreement with a model calculation that is adapted to the experimental situation. It accounts for the intensity dependence of the quantum beat structure through the coupling of the excited-state wave packet to other bound Ne states induced by the high-intensity infrared laser pulse.

  4. Monitoring transfer processes in the soil-plant-atmosphere continuum across scales using Distributed Temperature Sensing

    NASA Astrophysics Data System (ADS)

    Steele-Dunne, S. C.; Jansen, J. H. A. M.; Hatch, C.; Ochsner, T.; Cosh, M. H.; Dong, G.; van de Giesen, N.; Tyler, S.; Selker, J.

    2012-04-01

    Distributed Temperature Sensing (DTS) is presented as a novel experimental technique to monitor soil temperature, moisture and heat flux from the meter to kilometer scale. In DTS, fiber optic cables are used to measure temperature at a resolution of ~1m in cables up to 5km in length. Two strategies, Active and Passive DTS, can determine the soil thermal properties and moisture content. In Active DTS, a heat pulse is applied to the protective armor on the cable and the temperature response in the cable is monitored. This response depends on the thermal properties of the surrounding soil, variations in which are largely dependent on its moisture content. In Passive DTS, a profile of temperature measurements at different depths monitors soil temperature dynamics in response to the daily net radiation cycle. Amplitude and phase differences between the temperatures at different depths are dictated by the thermal properties of the soil. Amplitude analysis, an inversion approach or data assimilation can be used to infer the soil thermal properties (or moisture content) and heat fluxes. Results will be presented from two distinct field installations. Data collected from April to July 2011 at the SMAP Marena Oklahoma In-Situ Sensor Testbed (MOISST) were used to monitored soil temperature and moisture variations in a tallgrass prairie. Results are compared to continuous measurements from point sensors at three locations at the site, as well as distributed point measurements and large-area measurements from the new COSMOS sensor. From March to September 2011, cables were buried at a grass site in Delft, the Netherlands to measure soil moisture and heat flux. Results are validated with soil moisture, thermal property and energy balance measurements. Results from the two installations will be used to explain the technology, discuss the merits and challenges of using this approach, and to demonstrate its value as a tool to monitor transfer process in the soil

  5. A Lightness Scale from Image Intensity Distributions.

    DTIC Science & Technology

    1981-08-19

    same lightness scale (Resnikoff, 1975). But why is the end result always the same? Clearly, there must be some constraining influence independent of the...shading and shadows. In order to estimate the image intensity density function for surface texture, it is necessary to model the effects of these small...three-dimensional surface elements. Two such models will be considered. ’he first is a surface texture created by dis- tributing cylinderical

  6. Dual-peak solar cycle distribution of intense geomagnetic storms

    NASA Technical Reports Server (NTRS)

    Gonzalez, W. D.; Gonzalez, A. L. C.; Tsurutani, B. T.

    1990-01-01

    This paper studies the features of the solar cycle distribution of intense storms (Dst) during cycles 20 and 21 (1965-1985). For these cycles, the distribution of intense storms (including moderate events for this time interval) in terms of Dst values below -50 nT, showed a dual-peak distribution, providing evidence for another enhancement of the intense storm distribution at the late ascending phase of the cycle. The origin of the dual-peak distribution of intense storms is associated with a similar dual-peak distribution obtained for large-amplitude and long-duration values of the negative Bz component of the IMF, computed for the interval 1970-1981.

  7. Gamow-Teller strength distributions for {beta}{beta}-decaying nuclei within continuum quasiparticle random-phase approximation

    SciTech Connect

    Igashov, S. Yu.; Urin, M. H.; Rodin, Vadim; Faessler, Amand

    2011-04-15

    An isospin-self-consistent pn-continuum-QRPA approach is formulated and applied to describe the Gamow-Teller strength distributions for {beta}{beta}-decaying open-shell nuclei. Calculation results obtained for the pairs of nuclei {sup 76}Ge-Se, {sup 100}Mo-Ru, {sup 116}Cd-Sn, and {sup 130}Te-Xe are compared with available experimental data.

  8. Diffuse gamma radiation. [intensity, energy spectrum and spatial distribution from SAS 2 observations

    NASA Technical Reports Server (NTRS)

    Fichtel, C. E.; Simpson, G. A.; Thompson, D. J.

    1978-01-01

    Results are reported for an investigation of the intensity, energy spectrum, and spatial distribution of the diffuse gamma radiation detected by SAS 2 away from the galactic plane in the energy range above 35 MeV. The gamma-ray data are compared with relevant data obtained at other wavelengths, including 21-cm emission, radio continuum radiation, and the limited UV and radio information on local molecular hydrogen. It is found that there are two quite distinct components to the diffuse radiation, one of which shows a good correlation with the galactic matter distribution and continuum radiation, while the other has a much steeper energy spectrum and appears to be isotropic at least on a coarse scale. The galactic component is interpreted in terms of its implications for both local and more distant regions of the Galaxy. The apparently isotropic radiation is discussed partly with regard to the constraints placed on possible models by the steep energy spectrum, the observed intensity, and an upper limit on the anisotropy.

  9. Gamma-Ray Burst Intensity Distributions

    NASA Technical Reports Server (NTRS)

    Band, David L.; Norris, Jay P.; Bonnell, Jerry T.

    2004-01-01

    We use the lag-luminosity relation to calculate self-consistently the redshifts, apparent peak bolometric luminosities L(sub B1), and isotropic energies E(sub iso) for a large sample of BATSE bursts. We consider two different forms of the lag-luminosity relation; for both forms the median redshift, for our burst database is 1.6. We model the resulting sample of burst energies with power law and Gaussian dis- tributions, both of which are reasonable models. The power law model has an index of a = 1.76 plus or minus 0.05 (95% confidence) as opposed to the index of a = 2 predicted by the simple universal jet profile model; however, reasonable refinements to this model permit much greater flexibility in reconciling predicted and observed energy distributions.

  10. A comparison of modeled and observed intensity profiles for C2, C3, CN, and the continuum for P/Halley

    NASA Technical Reports Server (NTRS)

    Ellis, Tracy A.; Neff, John S.

    1992-01-01

    Model intensity profiles have been compared with those observed for the C2, C3, CN, and continuum emissions of Comet Halley, in order to constrain the dust and gas parameters. While most of the parameters were consistent with expected values, the lifetimes of C3 and its parent were unexpectedly small. The day:night production rate ratio, which was about 1:1 for the gas, covered the 4:3-1:0 range in the case of the dust.

  11. The nucleon intensity in the atmosphere and the Pt distribution

    NASA Technical Reports Server (NTRS)

    Liland, A.

    1985-01-01

    The diffusion equation for cosmic ray nucleons in the atmosphere has been solved analytically, taking into account the transverse momentum distribution of nucleons produced in nucleon-air nucleus collisions. The effect of the transverse momentum distribution increases the nucleon intensity at large zenith angles and low energies.

  12. Inertial particles distribute in turbulence as Poissonian points with random intensity inducing clustering and supervoiding

    NASA Astrophysics Data System (ADS)

    Schmidt, Lukas; Fouxon, Itzhak; Holzner, Markus

    2017-07-01

    This work considers the distribution of discrete inertial particles in turbulence. We demonstrate that even for weak inertia the distribution can be strongly different from the Poisson distribution that holds for tracers. We study the cases of weak inertia or strong gravity where single-valued particle flow holds in space. In these cases, the particles distribute over a random multifractal attractor in space. This attractor is characterized by fractal dimensions describing scaling exponents of moments of number of particles inside a ball with size much smaller than the viscous scale of turbulence. Previous studies used a continuum approach to the moments which requires having a large number of particles below the viscous scale. This condition often does not hold in practice; for instance, for water droplets in clouds there is typically one droplet per viscous scale. This condition is also hard to realize in numerical simulations. In this work, we overcome this difficulty by deriving the probability pl(k ) of having k particles in a ball of small radius l for which the continuum approximation may not hold. We demonstrate that the random point process formed by positions of particles' centers in space is a Poisson point process with log-normal random intensity (the so-called log Gaussian Cox process or LGCP). This gives pl(k ) in terms of the characteristic function of a log-normal distribution from which the moments are derived. This allows finding the correlation dimension relevant for statistics of particles' collisions. The case of zero number of particles provides the statistics of the size of voids—regions without particles—that were not studied previously. The probability of voids is increased compared to a random distribution of particles because preferential concentration of inertial particles implies voids in the deserted regions. Thus voids and preferential concentration are different reflections of the same phenomena. In the limit of tracers with zero

  13. Predicting the distribution of intensive poultry farming in Thailand

    PubMed Central

    Van Boeckel, Thomas P; Thanapongtharm, Weerapong; Robinson, Timothy; D’Aietti, Laura; Gilbert, Marius

    2012-01-01

    Intensification of animal production can be an important factor in the emergence of infectious diseases because changes in production structure influence disease transmission patterns. In 2004 and 2005, Thailand was subject to two highly pathogenic avian influenza epidemic waves and large surveys were conducted of the poultry sector, providing detailed spatial data on various poultry types. This study analysed these data with the aim of establishing the distributions of extensive and intensive poultry farms, based on the number of birds per holder. Once poultry data were disaggregated into these two production systems, they were analysed in relation to anthropogenic factors using simultaneous autoregressive models. Intensive chicken production was clustered around the capital city of Bangkok and close to the main consumption and export centres. Intensively-raised ducks, mainly free-grazing, showed a distinct pattern with the highest densities distributed in a large area located in the floodplain of the Chao Phraya River. Accessibility to Bangkok, the percentage of irrigated areas and human population density were the most important predictors explaining the geographical distribution of intensively-raised poultry. The distribution of extensive poultry showed a higher predictability. Extensive poultry farms were distributed more homogeneously across the country and their distribution was best predicted by human population density. PMID:22323841

  14. Predicting the distribution of intensive poultry farming in Thailand.

    PubMed

    Van Boeckel, Thomas P; Thanapongtharm, Weerapong; Robinson, Timothy; D'Aietti, Laura; Gilbert, Marius

    2012-03-01

    Intensification of animal production can be an important factor in the emergence of infectious diseases because changes in production structure influence disease transmission patterns. In 2004 and 2005, Thailand was subject to two highly pathogenic avian influenza epidemic waves and large surveys were conducted of the poultry sector, providing detailed spatial data on various poultry types. This study analysed these data with the aim of establishing the distributions of extensive and intensive poultry farms, based on the number of birds per holder. Once poultry data were disaggregated into these two production systems, they were analysed in relation to anthropogenic factors using simultaneous autoregressive models. Intensive chicken production was clustered around the capital city of Bangkok and close to the main consumption and export centres. Intensively-raised ducks, mainly free-grazing, showed a distinct pattern with the highest densities distributed in a large area located in the floodplain of the Chao Phraya River. Accessibility to Bangkok, the percentage of irrigated areas and human population density were the most important predictors explaining the geographical distribution of intensively-raised poultry. The distribution of extensive poultry showed a higher predictability. Extensive poultry farms were distributed more homogeneously across the country and their distribution was best predicted by human population density.

  15. Disparities in the Population Distribution of African American and Non-Hispanic White Smokers Along the Quitting Continuum

    PubMed Central

    Trinidad, Dennis R.; Xie, Bin; Fagan, Pebbles; Pulvers, Kim; Romero, Devan R.; Blanco, Lyzette; Sakuma, Kari-Lyn K.

    2017-01-01

    Purpose To examine disparities and changes over time in the population-level distribution of smokers along a cigarette quitting continuum among African American smokers compared with non-Hispanic Whites. Methods Secondary data analyses of the 1999, 2002, 2005, and 2008 California Tobacco Surveys (CTS). The CTS are large, random-digit-dialed, population-based surveys designed to assess changes in tobacco use in California. The number of survey respondents ranged from n = 6,744 to n = 12,876 across CTS years. Current smoking behavior (daily or nondaily smoking), number of cigarettes smoked per day, intention to quit in the next 6 months, length of most recent quit attempt among current smokers, and total length of time quit among former smokers were assessed and used to recreate the quitting continuum model. Results While current smoking rates were significantly higher among African Americans compared with non-Hispanic Whites across all years, cigarette consumption rates were lower among African Americans in all years. There were significant increases in the proportion of former smokers who had been quit for at least 12 months from 1999 (African Americans, 26.8% ± 5.5%; non-Hispanic Whites, 36.8% ± 1.6%) to 2008 (African Americans, 43.6% ± 4.1%; non-Hispanic Whites, 57.4% ± 2.9%). The proportion of African American former smokers in each CTS year was significantly lower than that of non-Hispanic Whites. Conclusions Despite positive progression along the quitting continuum for both African American and non-Hispanic White smokers, the overall distribution was less favorable for African Americans. The lower smoking consumption levels among African Americans, combined with the lower rates of successful smoking cessation, suggest that cigarette addiction and the quitting process may be different for African American smokers. PMID:25794519

  16. The ultraviolet spectrum and continuum energy distribution of the bright quasar H1821 + 643

    NASA Technical Reports Server (NTRS)

    Kolman, Michiel; Halpern, Jules P.; Shrader, Chris R.; Filippenko, Alexei V.

    1991-01-01

    The first UV observations of the bright QSO H1821 + 643 are reported. With V = 14.2 mag and z = 0.297, H1821 + 643 is the second brightest object in the sky at z above 0.1. The IUE data are combined with new optical spectroscopy, and existing IR and X-ray data, to reveal a strong optical/UV 'big bump', which continues past the Lyman limit in the rest frame of the QSO. A possible turnover at the high-frequency side of the UV continuum constrains fits of a thin accretion disk model to a large black hole mass and high accretion rate, but a small disk size. The shape of the UV continuum was found to be variable, with a hardening of the spectrum when the source was brighter. Because of its location, only 3 deg from the ecliptic pole, H1821 + 643 will be an important object for simultaneous UV and soft X-ray monitoring to test for a common origin of the UV bump and soft X-ray excess.

  17. A comparison of the radial distribution of molecular gas and non-thermal radio continuum in spiral disks

    NASA Technical Reports Server (NTRS)

    Devereux, Nicholas A.; Young, J. S.

    1990-01-01

    The present study includes 65 spiral galaxies selected from the Five College Radio Astronomy Observatory (FCRAO) Extragalactic CO Survey for which the major axis distributions of CO emission and 1.49 GHz radio continuum emission are well determined. The radial distribution of the CO emission has been measured with the FCRAO at positions along the major axis that are spaced by one half power beam width (HPBW) (45 seconds). The radial profile of the 1.49 GHz radio continuum emission was constructed by determining the radio emission at the location of the CO measurements from the 1.49 GHz maps of Condon (1987). Large, greater than a factor of ten, radially decreasing gradients in the star formation efficiency are observed for a small percentage, approx. 10 percent, of the spirals in this sample. The majority of spirals, however, are associated with small gradients in the star formation efficiency that do not systematically increase or decrease with radius. That the star formation efficiency does not systematically decrease with radius tends to argue against a global dynamical mechanism, such as a spiral density wave, for being the dominant mechanism triggering disk star formation for the majority of spirals in this sample. The results tend to support the view that the star formation in spiral disks is dominated by a local process that depends more on the molecular cloud properties than the dynamical structure of a galaxy.

  18. Recording the spatial distribution of coherent-radiation intensity

    SciTech Connect

    Zaslavskii, V.Y.; Przhevskii, S.S.; Shalomeeva, N.V.

    1986-01-01

    This paper discusses the feasibility of recording the spatial distribution of laser-radiation intensity, which is proven theoretically and confirmed by experiment. The authors consider the influence of the inhomogeneity and the wave front of radiation within the confines of a focusing optical element on the character of the diffracted image of the element.

  19. Foliage Density Distribution and Prediction of Intensively Managed Loblolly Pine

    Treesearch

    Yujia Zhang; Bruce E. Borders; Rodney E. Will; Hector De Los Santos Posadas

    2004-01-01

    The pipe model theory says that foliage biomass is proportional to the sapwood area at the base of the live crown. This knowledge was incorporated in an effort to develop a foliage biomass prediction model from integrating a stipulated foliage biomass distribution function within the crown. This model was parameterized using data collected from intensively managed...

  20. Intensity distribution function and statistical properties of fast radio bursts

    NASA Astrophysics Data System (ADS)

    Li, Long-Biao; Huang, Yong-Feng; Zhang, Zhi-Bin; Li, Di; Li, Bing

    2017-01-01

    Fast Radio Bursts (FRBs) are intense radio flashes from the sky that are characterized by millisecond durations and Jansky-level flux densities. We carried out a statistical analysis on FRBs that have been discovered. Their mean dispersion measure, after subtracting the contribution from the interstellar medium of our Galaxy, is found to be , supporting their being from a cosmological origin. Their energy released in the radio band spans about two orders of magnitude, with a mean value of erg. More interestingly, although the study of FRBs is still in a very early phase, the published collection of FRBs enables us to derive a useful intensity distribution function. For the 16 non-repeating FRBs detected by the Parkes telescope and the Green Bank Telescope, the intensity distribution can be described as , where is the observed radio fluence in units of Jy ms. Here the power-law index is significantly flatter than the expected value of 2.5 for standard candles distributed homogeneously in a flat Euclidean space. Based on this intensity distribution function, the Five-hundred-meter Aperture Spherical radio Telescope (FAST) is predicted to be able to detect about five FRBs for every 1000 h of observation time.

  1. 14 CFR 25.1389 - Position light distribution and intensities.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1389 Position... normal operating voltage of the airplane. The light distribution and intensity of each position light... the longitudinal axis of the airplane and perpendicular to the plane of symmetry of the airplane)...

  2. 14 CFR 25.1389 - Position light distribution and intensities.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1389 Position... normal operating voltage of the airplane. The light distribution and intensity of each position light... the longitudinal axis of the airplane and perpendicular to the plane of symmetry of the airplane)...

  3. 14 CFR 25.1389 - Position light distribution and intensities.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1389 Position... normal operating voltage of the airplane. The light distribution and intensity of each position light... the longitudinal axis of the airplane and perpendicular to the plane of symmetry of the airplane)...

  4. 14 CFR 25.1389 - Position light distribution and intensities.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1389 Position... normal operating voltage of the airplane. The light distribution and intensity of each position light... the longitudinal axis of the airplane and perpendicular to the plane of symmetry of the airplane)...

  5. 14 CFR 25.1389 - Position light distribution and intensities.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1389 Position... normal operating voltage of the airplane. The light distribution and intensity of each position light... the longitudinal axis of the airplane and perpendicular to the plane of symmetry of the airplane)...

  6. The Spatial Intensity Distribution of the UV light in HH objects. Revisited.

    NASA Astrophysics Data System (ADS)

    Moro-Martin, A.; Noriega-Crespo, A.

    1995-12-01

    At optical wavelengths it has been shown that many features observed in Herbig-Haro objects can be explained successfully by simplified bow shock models [1]. The goal is to extend this study into the ultraviolet, by comparing the spatial intensity distribution observed by IUE, with the scale-free models that describe the emission processes taking place in the leading "working surfaces" of the stellar jets. Published IUE spectra have been used for the HH1, HH2(A'+H), HH2(G+B), HH24A, HH32, HH43(A+B+C) and HH47 objects, where the brightest UV lines (CIV1549, CIII]1909, CII]2326, MgII2799) were studied, as well as the UV continuum (modeled by a two-photon continuum). The quality of the IUE data is rather limited, due to the broad PSF, the low signal-to-noise ratio and the small size of the IUE aperture, and therefore the models were degraded to compare with the observations. The physical parameters used in the models were obtained from previous optical studies and have been explored within the known uncertainties. The objects were modeled as single (HH1, HH24A, HH32, HH47), double (HH2[A'+H], HH2[G+B]) and triple (HH43[A+B+C]) condensations. It can be concluded that the simple geometrical kinematical three dimensional bow shock models [2][3][4] provide a reasonable description of the available IUE observations of HH objects UV spatial intensity distribution. [1] Noriega-Crespo, A., Bohm, K.H. & Raga, A.C. 1989, AJ, 98, 1388. [2] Raga, A.C., 1986, AJ, 92, 637. [3] Hartigan, P., Raymond, J., & Hartmann, L., 1987, ApJ, 316, 323. [4] Indebetouw, R., & Noriega-Crespo, A, 1995, AJ, 109, 752.

  7. Statistical Continuum Theory for the Effective Conductivity of Fiber Filled Polymer Composites: Effect of Orientation Distribution and Aspect Ratio

    SciTech Connect

    Mikdam, Amed; Makradi, A.; Ahzi, Said; Garmestani, Hamid; Li, Dongsheng; Remond, Y.

    2010-03-01

    Effective conductivity of polymer composites, filled with conducting fibers such as carbon nanotubes, is studied using statistical continuum theory. The fiber orientation distribution in the matrix plays a very important role on their effective properties. To take into account their orientation, shape and distribution, two-point and three-point probability distribution functions are used. The effect of fibers orientation is illustrated by comparing the effective conductivity of microstructures with oriented and non-oriented fibers. The randomly oriented fibers result in an isotropic effective conductivity. The increased fiber orientation distribution can lead to higher anisotropy in conductivity. The effect of fiber’s aspect ratio on the effective conductivity is studied by comparing microstructures with varying degrees of fiber orientation distribution. Results show that the increase in anisotropy leads to higher conductivity in the maximum fiber orientation distribution direction and lower conductivity in the transverse direction. These results are in agreement with various models from the literature that show the increase of the aspect ratio of fibers improves the electrical and thermal conductivity.

  8. Rapid intensification and the bimodal distribution of tropical cyclone intensity

    PubMed Central

    Lee, Chia-Ying; Tippett, Michael K.; Sobel, Adam H.; Camargo, Suzana J.

    2016-01-01

    The severity of a tropical cyclone (TC) is often summarized by its lifetime maximum intensity (LMI), and the climatological LMI distribution is a fundamental feature of the climate system. The distinctive bimodality of the LMI distribution means that major storms (LMI >96 kt) are not very rare compared with less intense storms. Rapid intensification (RI) is the dramatic strengthening of a TC in a short time, and is notoriously difficult to forecast or simulate. Here we show that the bimodality of the LMI distribution reflects two types of storms: those that undergo RI during their lifetime (RI storms) and those that do not (non-RI storms). The vast majority (79%) of major storms are RI storms. Few non-RI storms (6%) become major storms. While the importance of RI has been recognized in weather forecasting, our results demonstrate that RI also plays a crucial role in the TC climatology. PMID:26838056

  9. Subarcsecond observations of NGC 7538 IRS 1: Continuum distribution and dynamics of molecular gas

    SciTech Connect

    Zhu, Lei; Shi, Hui; Zhao, Jun-Hui; Wright, M. C. H.; Sandell, Göran; Wu, Yue-Fang; Brogan, Crystal; Corder, Stuartt

    2013-12-10

    We report new results based on the analysis of the Submillimeter Array (SMA) and Combined Array for Research in Millimeter-wave Astronomy (CARMA) observations of NGC 7538 IRS 1 at 1.3 and 3.4 mm with subarcsecond resolutions. With angular resolutions ∼0.''7, the SMA and CARMA observations show that the continuum emission at 1.3 and 3.4 mm from the hyper-compact H II region IRS 1 is dominated by a compact source with a tail-like extended structure to the southwest of IRS 1. With a CARMA B-array image at 1.3 mm convolved to 0.''1, we resolve the hyper-compact H II region into two components: an unresolved hyper-compact core, and a north-south extension with linear sizes of <270 AU and ∼2000 AU, respectively. The fine structure observed with CARMA is in good agreement with the previous Very Large Array results at centimeter wavelengths, suggesting that the hyper-compact H II region at the center of IRS 1 is associated with an ionized bipolar outflow. We image the molecular lines OCS(19-18) and CH{sub 3}CN(12-11) as well as {sup 13}CO(2-1) surrounding IRS 1, showing a velocity gradient along the southwest-northeast direction. The spectral line profiles in {sup 13}CO(2-1), CO(2-1), and HCN(1-0) observed toward IRS 1 show broad redshifted absorption, providing evidence for gas infall with rates in the range of 3-10 × 10{sup –3} M {sub ☉} yr{sup –1} inferred from our observations.

  10. Continuum radiation at Uranus

    SciTech Connect

    Kurth, W.S.; Gurnett, D.A. ); Desch, M.D. )

    1990-02-01

    Uranus has proven to be a radio source of remarkable complexity with as many as six distinctly different types of emission. One Uranian radio emission which has thus far escaped attention is an analog of continuum radiation at Earth, Jupiter, and Saturn. The emission is found to be propagating in the ordinary mode in the range of one to a few kHz on the inbound leg of the Voyager 2 encounter, shortly after the magnetopause crossing. The continuum radiation spectrum at Uranus also includes bands with frequencies as high as 12 kHz or greater on both the inbound and outbound legs. The Uranian continuum radiation is notably weak, making it more like that detected at Saturn than the extremely intense Jovian continuum radiation. The Uranian emission shows some evidence for narrow-band components lying in the same frequency regime as the continuum, completing the analogy with the other planets, which also show narrow-band components superimposed on the continuum spectrum. The authors argue that the low intensity of the Uranian continuum is most likely related to the lack of a density cavity within the Uranian magnetosphere that is deep relative to the solar wind plasma density.

  11. Does the Field of EBD Need a Distinct Set of "Intensive" Interventions or More Systemic Intensity within a Continuum of Social/Emotional Supports?

    ERIC Educational Resources Information Center

    Lewis, Timothy J.

    2016-01-01

    The challenges of educating children and youth with intensive social, emotional, and academic needs have been well documented. Students with emotional/ behavioral disorders (EBD) present a range of daily challenges from low intensity, high frequency chronic behaviors such as poor school attendance, disrespect addressed to adults and peers,…

  12. Does the Field of EBD Need a Distinct Set of "Intensive" Interventions or More Systemic Intensity within a Continuum of Social/Emotional Supports?

    ERIC Educational Resources Information Center

    Lewis, Timothy J.

    2016-01-01

    The challenges of educating children and youth with intensive social, emotional, and academic needs have been well documented. Students with emotional/ behavioral disorders (EBD) present a range of daily challenges from low intensity, high frequency chronic behaviors such as poor school attendance, disrespect addressed to adults and peers,…

  13. Exploring Macroinvertebrate Species Distributions at Regional and Local Scales across a Sandy Beach Geographic Continuum

    PubMed Central

    Rodil, Iván F.; Compton, Tanya J.; Lastra, Mariano

    2012-01-01

    Exposed sandy beaches are highly dynamic ecosystems where macroinvertebrate species cope with extremely variable environmental conditions. The majority of the beach ecology studies present exposed beaches as physically dominated ecosystems where abiotic factors largely determine the structure and distribution of macrobenthic communities. However, beach species patterns at different scales can be modified by the interaction between different environmental variables, including biotic interactions. In this study, we examined the role of different environmental variables for describing the regional and local scale distributions of common macrobenthic species across 39 beaches along the North coast of Spain. The analyses were carried out using boosted regression trees, a relatively new technique from the field of machine learning. Our study showed that the macroinvertebrate community on exposed beaches is not structured by a single physical factor, but instead by a complex set of drivers including the biotic compound. Thus, at a regional scale the macrobenthic community, in terms of number of species and abundance, was mainly explained by surrogates of food availability, such as chlorophyll a. The results also revealed that the local scale is a feasible way to construct general predictive species-environmental models, since relationships derived from different beaches showed similar responses for most of the species. However, additional information on aspects of beach species distribution can be obtained with large scale models. This study showed that species-environmental models should be validated against changes in spatial extent, and also illustrates the utility of BRTs as a powerful analysis tool for ecology data insight. PMID:22761841

  14. Combustion intensity and distribution relation to noise generation

    NASA Technical Reports Server (NTRS)

    Plett, E. G.; Leshner, M. D.; Summerfield, M.

    1975-01-01

    Experiments with several different flame holder geometries were conducted to investigate the degree to which combustion roughness can be altered by altering the flame intensity and flame distribution in a ducted combustion system. The effect of admitting primary air through a plane-slotted or a slotted-swirl vane flame holder was compared and the combustion roughness and noise was contrasted with that obtained with a closed front-end perforated can. The slotted front-end burners produced much smoother burning and less noise than the closed front-end can. No advantage was apparent with swirl vs nonswirl when approximately the same inlet flow distribution was maintained. Preheated inlet air provided somewhat smoother combustion as compared with ambient temperature air. The combustion roughness with methyl alcohol was briefly compared with that of isooctane; indications are that it burns more smoothly, but more detailed studies are needed to substantiate these indications.

  15. Exploiting remote sensing LST in distributed hydrological modelling: the example of the Continuum model

    NASA Astrophysics Data System (ADS)

    Rudari, Roberto; Silvestro, Francesco; Gabellani, Simone; Delogu, Fabio; Boni, Giorgio

    2013-04-01

    Complete and distribute models, based on physical equations must mimic a variety of hydro-meteorological processes. This can produce very complex models with a high degree of parameterization. The necessity to assimilate data of different nature observed by ground stations and remote sensors can be sometimes incompatible with the degree of complexity and parameterization of such models. In this work a model that balance the need of reproducing the physic of the processes and the practical goal of avoiding over-parameterization is presented. It is developed to be easily applied in different contexts even in data scarce environments. All main hydrological phenomena are modeled in a fully distributed way: overland flow, infiltration, sub-surface flow, vegetation, deep flow, water table evolution and evapotranspiration. Complete mass balance and energy balance are introduced with the capability of soil surface temperature estimation. A performance evaluation, based on both traditional and satellite derived data, is presented with a specific reference to the application to an Italian catchment. The model has been firstly calibrated and validated following a standard approach based on streamflow data. The capability of the model in reproducing both the streamflow measurements and the land surface temperature from satellites, has been investigated. The model has been then calibrated using satellite data and geomorphologic characteristic of the basin only in order to test its application on a basin where standard hydrologic observations (e.g., streamflow data) are not available. The results have been compared with those obtained by the standard calibration strategy based on streamflow data.

  16. Coupling length scales for multiscale atomistics-continuum simulations: atomistically induced stress distributions in Si/Si3N4 nanopixels.

    PubMed

    Lidorikis, E; Bachlechner, M E; Kalia, R K; Nakano, A; Vashishta, P; Voyiadjis, G Z

    2001-08-20

    A hybrid molecular-dynamics (MD) and finite-element simulation approach is used to study stress distributions in silicon/silicon-nitride nanopixels. The hybrid approach provides atomistic description near the interface and continuum description deep into the substrate, increasing the accessible length scales and greatly reducing the computational cost. The results of the hybrid simulation are in good agreement with full multimillion-atom MD simulations: atomic structures at the lattice-mismatched interface between amorphous silicon nitride and silicon induce inhomogeneous stress patterns in the substrate that cannot be reproduced by a continuum approach alone.

  17. Coupling Length Scales for Multiscale Atomistics-Continuum Simulations: Atomistically Induced Stress Distributions in Si/Si3N4 Nanopixels

    NASA Astrophysics Data System (ADS)

    Lidorikis, Elefterios; Bachlechner, Martina E.; Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya; Voyiadjis, George Z.

    2001-08-01

    A hybrid molecular-dynamics (MD) and finite-element simulation approach is used to study stress distributions in silicon/silicon-nitride nanopixels. The hybrid approach provides atomistic description near the interface and continuum description deep into the substrate, increasing the accessible length scales and greatly reducing the computational cost. The results of the hybrid simulation are in good agreement with full multimillion-atom MD simulations: atomic structures at the lattice-mismatched interface between amorphous silicon nitride and silicon induce inhomogeneous stress patterns in the substrate that cannot be reproduced by a continuum approach alone.

  18. Planck early results. XV. Spectral energy distributions and radio continuum spectra of northern extragalactic radio sources

    SciTech Connect

    Aatrokoski, J.

    2011-12-01

    Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources, based on the Planck Early Release Compact Source Catalogue (ERCSC) and simultaneous multifrequency data. The nine Planck frequencies, from 30 to 857GHz, are complemented by a set of simultaneous observations ranging from radio to gamma-rays. This is the first extensive frequency coverage in the radio and millimetre domains for an essentially complete sample of extragalactic radio sources, and it shows how the individual shocks, each in their own phase of development, shape the radio spectra as they move in the relativistic jet. The SEDs presented in this paper were fitted with second and third degree polynomials to estimate the frequencies of the synchrotron and inverse Compton (IC) peaks, and the spectral indices of low and high frequency radio data, including the Planck ERCSC data, were calculated. SED modelling methods are discussed, with an emphasis on proper, physical modelling of the synchrotron bump using multiple components. Planck ERCSC data also suggest that the original accelerated electron energy spectrum could be much harder than commonly thought, with power-law index around 1.5 instead of the canonical 2.5. The implications of this are discussed for the acceleration mechanisms effective in blazar shock. Furthermore in many cases the Planck data indicate that gamma-ray emission must originate in the same shocks that produce the radio emission.

  19. Properties of energetic-particle continuum modes destabilized by energetic ions with beam-like velocity distributions

    SciTech Connect

    Todo, Y.

    2006-08-15

    Properties of energetic-particle continuum modes (EPMs) destabilized by energetic ions in tokamak plasmas were investigated using a hybrid simulation code for magnetohydrodynamics and energetic particles. The energetic ions are assumed to have beam-like velocity distributions for the purpose of clarifying the dependence on energetic ion velocity. It was found that for beam velocities lower than the Alfven velocity, the unstable modes are EPMs while the toroidal Alfven eigenmodes are unstable for the beam velocities well above the Alfven velocity. The EPMs destabilized by the copassing energetic ions and those destabilized by the counterpassing energetic ions differ in primary poloidal harmonics and spatial locations. The frequencies of the EPMs are located close to the shear Alfven continuous spectrum when they are compared at the spatial peak locations of the primary poloidal harmonic or compared at the spatial tails if the primary poloidal harmonic is m=1. The frequencies of the EPMs were carefully compared with the energetic-ion orbital frequencies. It was found that the frequencies of the EPMs are in good agreement with the energetic-ion orbital frequencies with a correction for the toroidal circulation frequency. This demonstrates that the energetic-ion orbital frequency determines the EPM frequency.

  20. Precipitation Intensity and Events Distribution Changes in the Extratropics

    NASA Astrophysics Data System (ADS)

    Knight, R.; Groisman, P. Y.; Zolina, O. G.; Bulygina, O.

    2012-12-01

    More than ten years ago, Groisman et al. (1999) first reported large-scale changes in spectra of precipitation distribution intensity. At the tails of this distribution the frequencies in heavy and very heavy precipitation events have increased over many parts of the extratropics. These increases were disproportionally high in the regions where the precipitation totals increased and were observed even in the regions where the mean rainfall remained unchanged or decreased. Thereafter, this peculiarity of the contemporary precipitation distribution change was substantiated in many regional studies summarized by Groisman and Knight (2013) and will be reported in our presentation. Increases in the frequency of very heavy and extreme precipitation events (with return period of several years and decades respectively) are important for impact studies (assessment of soil erosion, potential of flood) but these events represent a small fraction in annual rainfall totals. Therefore, we analyzed the changes in the mean daily rainfall intensity over the northern extratropics in the regions well elucidated with dense gauge networks (southern Canada, contiguous U.S., Europe, Russia, and Japan). Nearly everywhere, we found systematic increases in daily rainfall totals per day with rain. While increases in very heavy and extreme rainfall intensity are an independent characteristic of the ongoing climatic change, the observed changes in mean precipitation intensity are in line with the ongoing global and regional warming. Duration of the sequences of wet days (prolonged rain events) increased in Europe and Northern Asia, and the duration of the sequences of dry days (prolonged no-rain events) increased over large parts of Northern Eurasia and North America (Zolina et al. 2010; Groisman and Knight 2007; 2013). To describe this feature of the rain events distribution, Zolina et al. (2012) suggested a visual interpretation of wet days as beads on the necklace of the seasonal cycle time

  1. Nonstationary distributions of wave intensities in wave turbulence

    NASA Astrophysics Data System (ADS)

    Choi, Yeontaek; Jo, Sanggyu; Kwon, Young-Sam; Nazarenko, Sergey

    2017-09-01

    We obtain a general solution for the probability density function (PDF) of wave intensities in non-stationary wave turbulence. The solution is expressed in terms of the initial PDF and the wave action spectrum satisfying the wave-kinetic equation. We establish that, in the absence of wave breaking, the wave statistics converge to a Gaussian distribution in forced-dissipated wave systems while approaching a steady state. Also, we find that in non-stationary systems, if the statistic is Gaussian initially, it will remain Gaussian for all time. Generally, if the statistic is not initially Gaussian, it will remain non-Gaussian over the characteristic nonlinear evolution time of the wave spectrum. In freely decaying wave turbulence, substantial deviations from Gaussianity may persist infinitely long.

  2. Spatial variability of "Did You Feel It?" intensity data: insights into sampling biases in historical earthquake intensity distributions

    USGS Publications Warehouse

    Hough, Susan E.

    2013-01-01

    Recent parallel development of improved quantitative methods to analyze intensity distributions for historical earthquakes and of web‐based systems for collecting intensity data for modern earthquakes provides an opportunity to reconsider not only important individual historical earthquakes but also the overall characterization of intensity distributions for historical events. The focus of this study is a comparison between intensity distributions of historical earthquakes with those from modern earthquakes for which intensities have been determined by the U.S. Geological Survey “Did You Feel It?” (DYFI) website (see Data and Resources). As an example of a historical earthquake, I focus initially on the 1843 Marked Tree, Arkansas, event. Its magnitude has been previously estimated as 6.0–6.2. I first reevaluate the macroseismic effects of this earthquake, assigning intensities using a traditional approach, and estimate a preferred magnitude of 5.4. Modified Mercalli intensity (MMI) values for the Marked Tree earthquake are higher, on average, than those from the 2011 >Mw 5.8 Mineral, Virginia, earthquake for distances ≤500  km but comparable or lower on average at larger distances, with a smaller overall felt extent. Intensity distributions for other moderate historical earthquakes reveal similar discrepancies; the discrepancy is also even more pronounced using earlier published intensities for the 1843 earthquake. I discuss several hypotheses to explain the discrepancies, including the possibility that intensity values associated with historical earthquakes are commonly inflated due to reporting/sampling biases. A detailed consideration of the DYFI intensity distribution for the Mineral earthquake illustrates how reporting and sampling biases can account for historical earthquake intensity biases as high as two intensity units and for the qualitative difference in intensity distance decays for modern versus historical events. Thus, intensity maps for

  3. Two-dimensional fluorescence intensity distribution analysis: theory and applications.

    PubMed

    Kask, P; Palo, K; Fay, N; Brand, L; Mets, U; Ullmann, D; Jungmann, J; Pschorr, J; Gall, K

    2000-04-01

    A method of sample analysis is presented which is based on fitting a joint distribution of photon count numbers. In experiments, fluorescence from a microscopic volume containing a fluctuating number of molecules is monitored by two detectors, using a confocal microscope. The two detectors may have different polarizational or spectral responses. Concentrations of fluorescent species together with two specific brightness values per species are determined. The two-dimensional fluorescence intensity distribution analysis (2D-FIDA), if used with a polarization cube, is a tool that is able to distinguish fluorescent species with different specific polarization ratios. As an example of polarization studies by 2D-FIDA, binding of 5'-(6-carboxytetramethylrhodamine) (TAMRA)-labeled theophylline to an anti-theophylline antibody has been studied. Alternatively, if two-color equipment is used, 2D-FIDA can determine concentrations and specific brightness values of fluorescent species corresponding to individual labels alone and their complex. As an example of two-color 2D-FIDA, binding of TAMRA-labeled somatostatin-14 to the human type-2 high-affinity somatostatin receptors present in stained vesicles has been studied. The presented method is unusually accurate among fluorescence fluctuation methods. It is well suited for monitoring a variety of molecular interactions, including receptors and ligands or antibodies and antigens.

  4. Intraluminal ultrasound intensity distribution and backscattered Doppler power.

    PubMed

    Thompson, Rosemary S; Bambi, Giacomo; Steel, Robin; Tortoli, Piero

    2004-11-01

    Ultrasound (US) incident obliquely on a cylindrical vessel is redistributed in space when the propagation path includes walls with acoustic impedance different from that of the surrounding media. We investigated this using low-density polyethylene (PE) as the vessel wall material. Both simulations and experiments were carried out. Direct hydrophone measurements of the acoustic field were made within a half section of the PE tube, and the distribution of backscattered Doppler power along a scan line was obtained using a range-Doppler instrument. Both simulation and hydrophone results demonstrate lateral shadow regions within the lumen. In every one of various Doppler flow experiments conducted, the backscattered Doppler power, compensated for on-axis transducer behaviour, increased with depth. Simulation results for an incident continuous-wave (CW) plane wave show that it tends to be focused by the curvature of the PE tube walls. The wall interactions are, however, angle-dependent and so the behaviour of a focused US beam depends on the beam as well as the walls. This study demonstrates alterations in the spatial distribution of US within a cylindrical vessel as a result of known vessel wall properties. It also provides evidence that local intensity variations within the lumen affect the relative Doppler power backscattered from small sample volumes.

  5. 14 CFR 29.1389 - Position light distribution and intensities.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... maximum intensities in overlapping beams, within dihedral angles, L, R, and A, and must meet the following... overlaps may be used with the use of main beam intensities substantially greater than the minima specified in §§ 29.1391 and 29.1393 if the overlap intensities in relation to the main beam intensities do not...

  6. 14 CFR 27.1389 - Position light distribution and intensities.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... intensities in overlapping beams, within dihedral angles L, R, and A, and must meet the following requirements... overlaps may be used with main beam intensities substantially greater than the minima specified in §§ 27.1391 and 27.1393, if the overlap intensities in relation to the main beam intensities do not adversely...

  7. Image intensity normalisation by maximising the Siddon line integral in the joint intensity distribution space.

    PubMed

    Kalemis, A; Binnie, D M; Flower, M A; Ott, R J

    2009-12-01

    This paper presents a novel data-driven method for image intensity normalisation, which is a prerequisite step for any kind of image comparison. The method involves a novel application of the Siddon algorithm that was developed initially for fast reconstruction of tomographic images and is based on a linear normalisation model with either one or two parameters. The latter are estimated by maximising the line integral, computed using the Siddon algorithm, in the 2D joint intensity distribution space of image pairs. The proposed normalisation method, referred to as Siddon Line Integral Maximisation (SLIM), was compared with three other methodologies, namely background ratio (BAR) scaling, linear fitting and proportional scaling, using a large number of synthesised datasets. SLIM was also compared with BAR normalisation when applied to phantom data and two clinical examples. The new method was found to be more accurate and less biased than its counterparts for the range of characteristics selected for the synthesised data. These findings were in agreement with the results from the analysis of the experimental and clinical data.

  8. Intensity distribution analysis of cathodoluminescence using the energy loss distribution of electrons.

    PubMed

    Fukuta, Masahiro; Inami, Wataru; Ono, Atsushi; Kawata, Yoshimasa

    2016-01-01

    We present an intensity distribution analysis of cathodoluminescence (CL) excited with a focused electron beam in a luminescent thin film. The energy loss distribution is applied to the developed analysis method in order to determine the arrangement of the dipole locations along the path of the electron traveling in the film. Propagating light emitted from each dipole is analyzed with the finite-difference time-domain (FDTD) method. CL distribution near the film surface is evaluated as a nanometric light source. It is found that a light source with 30 nm widths is generated in the film by the focused electron beam. We also discuss the accuracy of the developed analysis method by comparison with experimental results. The analysis results are brought into good agreement with the experimental results by introducing the energy loss distribution.

  9. Molecular above-threshold-ionization angular distributions with attosecond bichromatic intense XUV laser pulses

    NASA Astrophysics Data System (ADS)

    Yuan, Kai-Jun; Bandrauk, André D.

    2012-01-01

    Angular distributions of molecular above-threshold ionization (MATI) in bichromatic attosecond extreme ultraviolet (XUV) linear polarization laser pulses have been theoretically investigated. Multiphoton ionization in a prealigned molecular ion H2+ produces clear MATI spectra which show a forward-backward asymmetry in angular and momentum distributions which is critically sensitive to the carrier envelope phase (CEP) φ, the time delay Δτ between the two laser pulses, and the photoelectron kinetic energies Ee. The features of the asymmetry in MATI angular distributions are described well by multiphoton perturbative ionization models. Phase differences of continuum electron wave functions can be extracted from the CEP φ and time delay Δτ dependent ionization asymmetry ratio created by interfering multiphoton ionization pathways. At large internuclear distances MATI angular distributions exhibit more complex features due to laser-induced electron diffraction where continuum electron wavelengths are less than the internuclear distance.

  10. Nonlinear continuum growth model of multiscale reliefs as applied to rigorous analysis of multilayer short-wave scattering intensity. I. Gratings

    PubMed Central

    Goray, Leonid; Lubov, Maxim

    2013-01-01

    It is shown that taking into proper account certain terms in the nonlinear continuum equation of thin-film growth makes it applicable to the simulation of the surface of multilayer gratings with large boundary profile heights and/or gradient jumps. The proposed model describes smoothing and displacement of Mo/Si and Al/Zr boundaries of gratings grown on Si substrates with a blazed groove profile by magnetron sputtering and ion-beam deposition. Computer simulation of the growth of multilayer Mo/Si and Al/Zr gratings has been conducted. Absolute diffraction efficiencies of Mo/Si and Al/Zr gratings in the extreme UV range have been found within the framework of boundary integral equations applied to the calculated boundary profiles. It has been demonstrated that the integrated approach to the calculation of boundary profiles and of the intensity of short-wave scattering by multilayer gratings developed here opens up a way to perform studies comparable in accuracy to measurements with synchrotron radiation, at least for known materials and growth techniques. PMID:24046500

  11. Truncated Thermal Equilibrium Distribution for Intense Beam Propagation

    SciTech Connect

    Ronald C. Davidson; Hong Qin; Steven M. Lund

    2003-02-26

    An intense charged-particle beam with directed kinetic energy ({lambda}{sub b}-1)m{sub b}c{sup 2} propagates in the z-direction through an applied focusing field with transverse focusing force modeled by F{sub foc} = -{lambda}{sub b}m{sub b}{omega}{sub beta}{sup 2} {perpendicular} x {perpendicular} in the smooth focusing approximation. This paper examines properties of the axisymmetric, truncated thermal equilibrium distribution F(sub)b(r,p perpendicular) = A exp (-H Perpendicular/T perpendicular (sub)b) = (H perpendicular-E(sub)b), where A, T perpendicular (sub)b, and E (sub)b are positive constants, and H perpendicular is the Hamiltonian for transverse particle motion. The equilibrium profiles for beam number density, n(sub)b(r) = * d{sup 2}pF(sub)b(r,p perpendicular), and transverse temperature, T perpendicular (sub)b(r) = * d{sup 2}p(p{sup 2} perpendicular/2 lambda (sbu)bm (sub)b)F(sub)b(r,p perpendicular), are calculated self-consistently including space-charge effects. Several properties of the equilibrium profiles are noteworthy. For example, the beam has a sharp outer edge radius r(sub)b with n(sub)b(r greater than or equal to rb) = 0, where r(sub)b depends on the value of E(sub)b/T (sub)perpendicular(sub)b. In addition, unlike the choice of a semi-Gaussian distribution, F{sup SG}(sub)b = A exp (-p{sup 2}(sub)perpendicular/2lambda(sub)bm(sub)bTperpendicular(sub)b) = (r-r(sub)b), the truncated thermal equilibrium distribution F(sub)b(r,p) depends on (r,p) only through the single-particle constant of the motion Hperpendiuclar and is therefore a true steady-state solution (*/*t = 0) of the nonlinear Vlasov-Maxwell equations.

  12. The use of distributed temperature sensing technology for monitoring wildland fire intensity and distribution.

    NASA Astrophysics Data System (ADS)

    Ochoa, C. G.; Cram, D.; Hatch, C. E.; Tyler, S. W.

    2014-12-01

    Distributed temperature sensing (DTS) technology offers a viable alternative for accurately measuring wildland fire intensity and distribution in real time applications. We conducted an experiment to test the use of DTS as an alternative technology to monitor prescribed fire temperatures in real time and across a broad spatial scale. The custom fiber-optic cable consisted of three fiber optic lines buffered by polyamide, copper, and polyvinyl chloride, respectively, each armored in a stainless steel tube backfilled with Nitrogen gas. The 150 m long cable was deployed in three different 20 by 26 m experimental plots of short-grass rangeland in central New Mexico. Cable was arranged to maximize coverage of the experimental plots and allow cross-comparison between two main parallel straight-line sections approximately 8 m apart. A DTS system recorded fire temperatures every three seconds and integrated every one meter. A series of five thermocouples attached to a datalogger were placed at selected locations along the cable and also recorded temperature data every three seconds on each fiber. Results indicate that in general there is good agreement between thermocouple-measured and DTS-measured temperatures. A close match in temperature between DTS and thermocouples was particularly observed during the rising limb but not so much during the decline. The metal armoring of the fiber-optic cable remained hot longer than the thermocouples after the flames had passed. The relatively short-duration, high-intensity, prescribed burn fire in each plot resulted in temperatures reaching up to 450 degrees Celsius. In addition, DTS data allow for illustration of the irregular nature of flame speed and travel path across the rangeland grasses, a phenomenon that was impossible to quantify without the use of this tool. This study adds to the understanding of using DTS as a new alternative tool for better characterizing wildland fire intensity, distribution and travel patterns, and

  13. The Spatial Intensity Distribution of the UV Light in HH Objects. Revisited

    NASA Technical Reports Server (NTRS)

    Moro-Martin, A.; Noriego-Crespo, A.; Boehm, K.-H.; Raga, A. C.

    1996-01-01

    Simple kinematical bow shock models have successfylly explained many of the observed features in Herbig-Haro objects. It is shown that similar models can be applied to the spatial intensity distribution of the UV lines observed by IUE. Archival IUE spectra have been used for the HH 1, HH 2(H+A'), HH 2(G+B), HH 24A, HH 32A, HH 43(A+B+C), and HH 47A objects where the brightest UV lines (C IV (lambda)1549,Si III(lambda)1891, C III] (lambda)1909, C II] (lambda)2326, MgII (lambda)2799) were studied, as well as the UV continuum (modeled by the hydrogen two-photon contiuum). The quality of the IUE data is rather limited due to the broad point spread function and the low signal-to-noise, and therefore the models were degraded to make them comparable to the observations. The physical parameters used in the models were obtained from previous optical studies and varied accordingly to match the observations, but within the known uncertainties. The objects were modeled by a single bow shock model (i.e., HH 1, HH 24A, HH 32A, and HH 47A) or the superposition of two (i.e., HH 2(H+A') and HH 2(G+B) or more (i.e., HH 43(A+B+C)) of them. The idea was to take into account the complexity of the morphology of these objects, and the contribution to the UV light from diffrent condensations within the IUE aperature.

  14. The Spatial Intensity Distribution of the UV Light in HH Objects. Revisited

    NASA Technical Reports Server (NTRS)

    Moro-Martin, A.; Noriego-Crespo, A.; Boehm, K.-H.; Raga, A. C.

    1996-01-01

    Simple kinematical bow shock models have successfylly explained many of the observed features in Herbig-Haro objects. It is shown that similar models can be applied to the spatial intensity distribution of the UV lines observed by IUE. Archival IUE spectra have been used for the HH 1, HH 2(H+A'), HH 2(G+B), HH 24A, HH 32A, HH 43(A+B+C), and HH 47A objects where the brightest UV lines (C IV (lambda)1549,Si III(lambda)1891, C III] (lambda)1909, C II] (lambda)2326, MgII (lambda)2799) were studied, as well as the UV continuum (modeled by the hydrogen two-photon contiuum). The quality of the IUE data is rather limited due to the broad point spread function and the low signal-to-noise, and therefore the models were degraded to make them comparable to the observations. The physical parameters used in the models were obtained from previous optical studies and varied accordingly to match the observations, but within the known uncertainties. The objects were modeled by a single bow shock model (i.e., HH 1, HH 24A, HH 32A, and HH 47A) or the superposition of two (i.e., HH 2(H+A') and HH 2(G+B) or more (i.e., HH 43(A+B+C)) of them. The idea was to take into account the complexity of the morphology of these objects, and the contribution to the UV light from diffrent condensations within the IUE aperature.

  15. Interferometric coherence measurement and radio frequency noise characterization of the 1.3 μm femtosecond intense Stokes continuum from a TZDW source

    NASA Astrophysics Data System (ADS)

    Yao, Yuhong; Knox, Wayne H.

    2015-02-01

    Photonic crystal fiber (PCF) with two closely spaced zero dispersion wavelengths (TZDW) offers a unique route to efficient energy transfer to two spectrally localized continua beyond either side of the ZDWs, which we have employed in previous work for mid-IR difference frequency generation and speckle-free red-green-blue generation. In this manuscript, we report the interferometric coherence characterization and radio frequency (RF) noise measurements of the Stokes side TZDW component. With a custom-built 1.3 W, 1035 nm, 40 MHz, 240 fs Yb:fiber chirped pulse amplifier as the pump source, we use 12 cm of commercially available TZDW PCF to excite the dual narrow-band continua from which the Stokes pulse is filtered out with a 1180 nm long wave pass filter. We achieve 0.8 to 3 nJ of narrow-band pulses within the spectral range of 1200 - 1315 nm at an average power conversion efficiency of 33%. Employing an un-balanced Michelson interferometer, measured mutual spectral coherence of the Stokes pulse is in excess of 0.76 with pump Soliton order as high as N ~70. Its measured RF noise spectrum at the first harmonic of the laser repetition rate shows less than 8 dBc/Hz increase in relative intensity noise (RIN) compared to that of the power amplifier, which is consistent with reported studies employing sub-100 fs pulses from relatively low noise oscillators. In contrast to the broadband continuum from a single ZDW PCF wherein severe de-coherence is found with pumping at high soliton order and longer pump pulse width, the reported TZDW fiber source shows preservation of intensity stability and phase coherence against variation in pump pulse parameters, which not only attests to the stability of our reported method for mid-IR generation, but also shows promising potential towards an all-fiber, efficient and low noise ultrafast source that can be helpful for applications such as biomedical deep-tissue imaging.

  16. Impact of training intensity distribution on performance in endurance athletes.

    PubMed

    Esteve-Lanao, Jonathan; Foster, Carl; Seiler, Stephen; Lucia, Alejandro

    2007-08-01

    The purpose of this study was to compare the effect of 2 training programs differing in the relative contribution of training volume, clearly below vs. within the lactate threshold/maximal lactate steady state region on performance in endurance runners. Twelve subelite endurance runners (who are specialists in track events, mostly the 5,000-m race usually held during spring-summer months and who also participate in cross-country races [9-12 km] during fall and winter months) were randomly assigned to a training program emphasizing low-intensity (subthreshold) (Z1) or moderately high-intensity (between thresholds) (Z2) training intensities. At the start of the study, the subjects performed a maximal exercise test to determine ventilatory (VT) and respiratory compensation thresholds (RCT), which allowed training to be controlled based on heart rate during each training session over a 5-month training period. Subjects performed a simulated 10.4-km cross-country race before and after the training period. Training was quantified based on the cumulative time spent in 3 intensity zones: zone 1 (low intensity; intensity; between VT and RCT), and zone 3 (high intensity; >RCT). The contribution of total training time spent in zones 1 and 2 was controlled to have relatively more low-intensity training in Z1 (80.5 +/- 1.8% and 11.8 +/- 2.0%, respectively) than in Z2 (66.8 +/- 1.1% and 24.7 +/- 1.5%, respectively), whereas the contribution of high-intensity (zone 3) training was similar (8.3 +/- 0.7% [Z1] and 8.5 +/- 1.0% [Z2]). The magnitude of the improvement in running performance was significantly greater (p = 0.03) in Z1 (-157 +/- 13 seconds) than in Z2 (-121.5 +/- 7.1 seconds). These results provide experimental evidence supporting the value of a relatively large percentage of low-intensity training over a long period ( approximately 5 months), provided that the contribution of high-intensity training remains sufficient.

  17. Features of electromagnetic radiation time-and-frequency fluctuation intensity distributions from human brain structures.

    PubMed

    Kublanov, V S; Gasilov, V L; Kazakov, Y E

    2000-01-01

    Time-and-frequency fluctuation intensity distributions' analysis is made of the electromagnetic radiation obtained from deep human brain structures. The role of monitoring the distribution changes due to various cerebral circulation disorders is explained.

  18. Coupling-of-length-scale approach for multiscale atomistic-continuum simulations: Atomistically-induced stress distributions in Si/Si_3N4 nanopixels

    NASA Astrophysics Data System (ADS)

    Lidorikis, Elefterios; Bachlechner, Martina E.; Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya; Voyiadjis, George; Madhukar, Anupam

    2001-03-01

    A hybrid molecular-dynamics and finite-element simulation approach has been used to investigate stress distributions in Si(111) nanopixels covered with both crystalline and amorphous Si_3N4 thin films. Surfaces, lattice-mismatched interfaces, edges, and corners create stress fields on the order of 1 GPa inside the Si substrate with patterns that cannot be reproduced by a continuum approach alone. For these atomistically-induced inhomogeneouse stresses, the hybrid simulation approach provides an excellent agreement with the standard molecular dynamics, with considerably less computational costs.

  19. Software architecture for large scale, distributed, data-intensive systems

    NASA Technical Reports Server (NTRS)

    Mattmann, Chris A.; Medvidovic, Nenad; Ramirez, Paul M.

    2004-01-01

    This paper presents our experience with OODT, a novel software architectual style, and middlware-based implementation for data-intensive systems. To date, OODT has been successfully evaluated in several different science domains including Cancer Research with the National Cancer Institute (NCI), and Planetary Science with NASA's Planetary Data System (PDS).

  20. Utilizing angular distributions to measure the spin imparted to the continuum region of Gd nuclei by light-ion transfer reactions

    NASA Astrophysics Data System (ADS)

    Ross, T. J.; Beausang, C. W.; Hughes, R. O.; Allmond, J. M.; Angell, C. T.; Basunia, M. S.; Bleuel, D. L.; Burke, J. T.; Casperson, R. J.; Escher, J. E.; Fallon, P.; Hatarik, R.; Munson, J.; Paschalis, S.; Petri, M.; Phair, L.; Ressler, J. J.; Scielzo, N. D.; Thompson, I. J.

    2012-10-01

    Historically it has proven extremely difficult to probe the properties of low-spin highly-excited states far above the yrast line in the bound quasi-continuum. We present the first measurement of the initial spin distribution of this region, following (p,d) and (p,t) reactions on ^154Gd and ^158Gd targets. The 25 MeV proton beam was provided by the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. A silicon telescope array, STARS, was used to detect light ions. We find that the spin transferred increases with excitation energy. Between 3 and 8 MeV, assuming a single dominant angular momentum transfer component, the measured angular distribution for the (p,d) reactions are well reproduced by DWBA calculations for δL=4 transfer, whilst the (p,t) reactions are better characterized by δL=5. A weighted combination of DWBA calculations, agrees excellently with experimental angular distributions.

  1. Investigation intensity response of distributed-feedback fiber laser to external acoustic excitation Investigation intensity response of DFB fiber laser

    NASA Astrophysics Data System (ADS)

    Wang, P. P.; Chang, J.; Zhu, C. G.; Wang, W. J.; Zhao, Y. J.; Zhang, X. L.; Peng, G. D.; Lv, G. P.; Liu, X. Z.; Wang, H.

    2012-08-01

    The intensity response of distributed-feedback (DFB) fiber laser to external acoustic excitation has been investigated. On that basis, an intensity modulated sensing system based on DFB fiber laser has been constructed. Acoustic pressure sensitivity of the intensity-type sensor at frequencies ranging from 800 Hz to 9 kHz has been obtained by experiments for the first time to the authors' knowledge. In addition, intensity response property of DFB fiber laser to external acoustic excitation with different pump power has been analyzed. We conclude that the signal power increases with the pump drive current of 980 nm laser diode (LD), and yet the ratios of signal power to DFB fiber laser power decrease. It confirms that the anti-interference performance of DFB fiber laser to fixed external acoustic interference becomes stronger with the increasing current of pump source, and this conclusion is beneficial to the investigation of wavelength demodulated sensors.

  2. Improvement of the f ceo S/N of Er-doped fiber laser combs with super-continuum power distribution optimization

    NASA Astrophysics Data System (ADS)

    Zhou, Dawei; Dai, Shaoyang; Wang, Qing; Qi, Xianghui; Chen, Xuzong

    2017-06-01

    We demonstrate an Er-doped fiber comb with a significant increase of the carrier envelope offset frequency (f ceo) signal to noise ratio (S/N), by forcing nearly all the super-continuum (SC) power in the vicinity of the pump wavelengths to the two ends. As the wavelength and spectrum width of the pump pulse strongly affect SC power distribution, we use two steps to drive the SC power distribution to the two ends: (1) we alter the pump wavelength from 1565 nm to 1585 nm by modifying the pulse amplifier; (2) we adjust the seed pulse to decrease the FWHM of the pump pulse spectrum from 23 nm to 12 nm. As a result of our optimization, we are able to improve the f ceo S/N at a 300 kHz resolution bandwidth from 35 dB to 46 dB.

  3. From Discrete 1 to 10 Towards Continuous 0 to 10: The Continuum Approach to Estimating the Distribution of Happiness in a Nation.

    PubMed

    Kalmijn, Wim

    2013-01-01

    Happiness is often measured in surveys using responses to a single question with a limited number of response options, such as 'very happy', 'fairly happy' and 'not too happy'. There is much variety in the wording and number of response options used, which limits comparability across surveys. To solve this problem, descriptive statistics of the discrete distribution in the sample are often transformed to a common discrete secondary scale, mostly ranging from 0 to 10. In an earlier publication we proposed a method for estimating statistics of the corresponding continuous distribution in the population (Kalmijn 2010). In the present paper we extend this method to questions using numerical response scales. The application of this 'continuum approach' to results obtained using the often used 1-10 numerical scale can make these comparable to those obtained on the basis of verbal response scales.

  4. Frequency Distribution of Seismic Intensity in Japan between 1950 and 2009

    NASA Astrophysics Data System (ADS)

    Kato, M.; Kohayakawa, Y.

    2012-12-01

    JMA Seismic Intensity is an index of seismic ground motion which is frequently used and reported in the media. While it is always difficult to represent complex ground motion with one index, the fact that it is widely accepted in the society makes the use of JMA Seismic Intensity preferable when seismologists communicate with the public and discuss hazard assessment and risk management. With the introduction on JMA Instrumental Intensity in 1996, the number of seismic intensity observation sites has substantially increased and the spatial coverage has improved vastly. Together with a long history of non-instrumental intensity records, the intensity data represent some aspects of the seismic ground motion in Japan. We investigate characteristics of seismic ground motion between 1950 and 2009 utilizing JMA Seismic Intensity Database. Specifically we are interested in the frequency distribution of intensity recordings. Observations of large intensity is rare compared to those of small intensity, and previous studies such as Ikegami [1961] demonstrated that frequency distribution of observed intensity obeys an exponential law, which is equivalent to the Ishimoto-Iida law [Ishimoto & Iida, 1939]. Such behavior could be used to empirically construct probabilistic seismic hazard maps [e.g., Kawasumi, 1951]. For the recent instrumental intensity data as well as pre-instrumental data, we are able to confirm that Ishimoto-Iida law explains the observation. Exponents of the Ishimoto-Iida law, or slope of the exponential law in the semi-log plot, is approximately 0.5. At stations with long recordings, there is no apparent difference between pre-instrumental and instrumental intensities when Ishimoto-Iida law is used as a measure. Numbers of average intensity reports per year and exponents of the frequency distribution curve vary regionally and local seismicity is apparently the controlling factor. The observed numbers of large intensity is slightly less than extrapolated and

  5. Absolute intensity calibration of flat-field space-resolved extreme ultraviolet spectrometer using radial profiles of visible and extreme ultraviolet bremsstrahlung continuum emitted from high-density plasmas in Large Helical Device

    SciTech Connect

    Dong Chunfeng; Wang Erhui; Morita, Shigeru; Goto, Motoshi

    2011-11-15

    A precise absolute intensity calibration of a flat-field space-resolved extreme ultraviolet (EUV) spectrometer working in wavelength range of 60-400 A is carried out using a new calibration technique based on radial profile measurement of the bremsstrahlung continuum in Large Helical Device. A peaked vertical profile of the EUV bremsstrahlung continuum has been successfully observed in high-density plasmas (n{sub e}{>=} 10{sup 14} cm{sup -3}) with hydrogen ice pellet injection. The absolute calibration can be done by comparing the EUV bremsstrahlung profile with the visible bremsstrahlung profile of which the absolute value has been already calibrated using a standard lamp. The line-integrated profile of measured visible bremsstrahlung continuum is firstly converted into the local emissivity profile by considering a magnetic surface distortion due to the plasma pressure, and the local emissivity profile of EUV bremsstrahlung is secondly calculated by taking into account the electron temperature profile and free-free gaunt factor. The line-integrated profile of the EUV bremsstrahlung continuum is finally calculated from the local emissivity profile in order to compare with measured EUV bremsstrahlung profile. The absolute intensity calibration can be done by comparing measured and calculated EUV bremsstrahlung profiles. The calibration factor is thus obtained as a function of wavelength with excellent accuracy. It is also found in the profile analysis that the grating reflectivity of EUV emissions is constant along the direction perpendicular to the wavelength dispersion. Uncertainties on the calibration factor determined with the present method are discussed including charge-coupled device operation modes.

  6. Numerical research of two-dimension temperature distribution in bio-tissue induced by pulse laser and continuum laser based on FEM

    NASA Astrophysics Data System (ADS)

    Shan, Ning; Zhan, Renjun; Cui, Heping

    2013-09-01

    Laser has several advantages, such as strong anti-interference ability, quick speed, high power, agility and precision. It is widely applied in military and medicine fields. When laser acts on human body, biological tissue of human body will appear the phenomenon of ablation and carbonization and solidification. In order to effectively defend excess damage by laser, the thermal effect research of skin tissue should be carried out. The heating rate and thermal damage area should be studied. In the paper, thermal energy production and thermal exchange loss used in living tissue is analyzed. The rule of thermal transfer that is irradiated by high power laser is discussed. The model of two dimensional skin tissues is built. The two dimensional transient temperature distribution generated by laser irradiation in bio-tissue is numerical simulated using finite element method. The temperature change trend generated by pulse laser and continuum laser in different radial length and axial depth bio-tissue are studied respectively. The results show that FEM method can reflect the photothermal conversion of bio-tissue exactly. Temperature is the highest in the local tissue by laser irradiated directly. The highest temperature decreases along with increasing radial length and axial depth. The highest temperature rise generated by pulse laser is more than continuum laser's. The highest temperature generated by pulse laser is not monotone increasing but is oscillation trend. The highest temperature generated by continuum laser is monotone increasing. The temperature rise mainly occurs in exodermis and derma. The temperature rise is not very significant in fat acid lining.

  7. Rogue-wave-like statistics in ultrafast white-light continuum generation in sapphire.

    PubMed

    Majus, D; Jukna, V; Pileckis, E; Valiulis, G; Dubietis, A

    2011-08-15

    We experimentally study the statistics of the white-light continuum generated by focusing of 130 fs, 800 nm pulses in a sapphire plate and show that the statistical distributions of the spectral intensity of the blue-shifted continuum components obey the extreme-value statistics. This rogue-wave-like behavior is detected only within a narrow input-pulse energy interval. By the use of numerical simulations, we show that the observed rogue-wave-like behavior is associated with pulse splitting and build-up of intense trailing pulse. The extreme events are thereafter suppressed by the intensity clamping.

  8. Understanding the distributed cognitive processes of intensive care patient discharge.

    PubMed

    Lin, Frances; Chaboyer, Wendy; Wallis, Marianne

    2014-03-01

    To better understand and identify vulnerabilities and risks in the ICU patient discharge process, which provides evidence for service improvement. Previous studies have identified that 'after hours' discharge and 'premature' discharge from ICU are associated with increased mortality. However, some of these studies have largely been retrospective reviews of various administrative databases, while others have focused on specific aspects of the process, which may miss crucial components of the discharge process. This is an ethnographic exploratory study. Distributed cognition and activity theory were used as theoretical frameworks. Ethnographic data collection techniques including informal interviews, direct observations and collecting existing documents were used. A total of 56 one-to-one interviews were conducted with 46 participants; 28 discharges were observed; and numerous documents were collected during a five-month period. A triangulated technique was used in both data collection and data analysis to ensure the research rigour. Under the guidance of activity theory and distributed cognition theoretical frameworks, five themes emerged: hierarchical power and authority, competing priorities, ineffective communication, failing to enact the organisational processes and working collaboratively to optimise the discharge process. Issues with teamwork, cognitive processes and team members' interaction with cognitive artefacts influenced the discharge process. Strategies to improve shared situational awareness are needed to improve teamwork, patient flow and resource efficiency. Tools need to be evaluated regularly to ensure their continuous usefulness. Health care professionals need to be aware of the impact of their competing priorities and ensure discharges occur in a timely manner. Activity theory and distributed cognition are useful theoretical frameworks to support healthcare organisational research. © 2013 John Wiley & Sons Ltd.

  9. Longitudinal intensity distribution near the focus produced by light through scattering media

    NASA Astrophysics Data System (ADS)

    Ji, Xuan-Xuan; Wan, Li-Peng; Chen, Zi-Yang; Pu, Ji-Xiong

    2017-08-01

    Speckle pattern is formed when coherent light passes through scattering media. It has been demonstrated that after appropriately optimizing the phase of the incident light, a bright focal spot in the target point can be obtained for the case that the light passes through the scattering medium. However, until now the focused intensity distribution near the focus seems unclear. In this paper we experimentally investigate some factors influencing the longitudinal intensity distribution near the focus in details. It is shown that the desired longitudinal focused intensity distribution can be obtained by optimizing the incident light. The results may have potential applications in particle manipulation and laser processing, etc.

  10. Computationally intensive econometrics using a distributed matrix-programming language.

    PubMed

    Doornik, Jurgen A; Hendry, David F; Shephard, Neil

    2002-06-15

    This paper reviews the need for powerful computing facilities in econometrics, focusing on concrete problems which arise in financial economics and in macroeconomics. We argue that the profession is being held back by the lack of easy-to-use generic software which is able to exploit the availability of cheap clusters of distributed computers. Our response is to extend, in a number of directions, the well-known matrix-programming interpreted language Ox developed by the first author. We note three possible levels of extensions: (i) Ox with parallelization explicit in the Ox code; (ii) Ox with a parallelized run-time library; and (iii) Ox with a parallelized interpreter. This paper studies and implements the first case, emphasizing the need for deterministic computing in science. We give examples in the context of financial economics and time-series modelling.

  11. Where does HIT fit? An examination of the affective response to high-intensity intervals in comparison to continuous moderate- and continuous vigorous-intensity exercise in the exercise intensity-affect continuum.

    PubMed

    Jung, Mary E; Bourne, Jessica E; Little, Jonathan P

    2014-01-01

    Affect experienced during an exercise session is purported to predict future exercise behaviour. Compared to continuous moderate-intensity exercise (CMI), the affective response to continuous vigorous-intensity exercise (CVI) has consistently been shown to be more aversive. The affective response, and overall tolerability to high-intensity interval training (HIT), is less studied. To date, there has yet to be a comparison between HIT, CVI, and CMI. The purpose of this study was to compare the tolerability and affective responses during HIT to CVI and CMI. This study utilized a repeated measures, randomized, counter-balanced design. Forty-four participants visited the laboratory on four occasions. Baseline fitness testing was conducted to establish peak power output in Watts (W peak). Three subsequent visits involved a single bout of a) HIT, corresponding to 1-minute at ∼ 100% W peak and 1-minute at ∼ 20% W peak for 20 minutes, b) CMI, corresponding to ∼ 40% W peak for 40 minutes, and c) CVI, corresponding to ∼ 80% W peak for 20 minutes. The order of the sessions was randomized. Affective responses were measured before, during and after each session. Task self-efficacy, intentions, enjoyment and preference were measured after sessions. Participants reported greater enjoyment of HIT as compared to CMI and CVI, with over 50% of participants reporting a preference to engage in HIT as opposed to either CMI or CVI. HIT was considered more pleasurable than CVI after exercise, but less pleasurable than CMI at these times. Despite this participants reported being just as confident to engage in HIT as they were CMI, but less confident to engage in CVI. This study highlights the utility of HIT in inactive individuals, and suggests that it may be a viable alternative to traditionally prescribed continuous modalities of exercise for promoting self-efficacy and enjoyment of exercise.

  12. Where Does HIT Fit? An Examination of the Affective Response to High-Intensity Intervals in Comparison to Continuous Moderate- and Continuous Vigorous-Intensity Exercise in the Exercise Intensity-Affect Continuum

    PubMed Central

    Jung, Mary E.; Bourne, Jessica E.; Little, Jonathan P.

    2014-01-01

    Affect experienced during an exercise session is purported to predict future exercise behaviour. Compared to continuous moderate-intensity exercise (CMI), the affective response to continuous vigorous-intensity exercise (CVI) has consistently been shown to be more aversive. The affective response, and overall tolerability to high-intensity interval training (HIT), is less studied. To date, there has yet to be a comparison between HIT, CVI, and CMI. The purpose of this study was to compare the tolerability and affective responses during HIT to CVI and CMI. This study utilized a repeated measures, randomized, counter-balanced design. Forty-four participants visited the laboratory on four occasions. Baseline fitness testing was conducted to establish peak power output in Watts (Wpeak). Three subsequent visits involved a single bout of a) HIT, corresponding to 1-minute at ∼100% Wpeak and 1-minute at ∼20% Wpeak for 20 minutes, b) CMI, corresponding to ∼40% Wpeak for 40 minutes, and c) CVI, corresponding to ∼80% Wpeak for 20 minutes. The order of the sessions was randomized. Affective responses were measured before, during and after each session. Task self-efficacy, intentions, enjoyment and preference were measured after sessions. Participants reported greater enjoyment of HIT as compared to CMI and CVI, with over 50% of participants reporting a preference to engage in HIT as opposed to either CMI or CVI. HIT was considered more pleasurable than CVI after exercise, but less pleasurable than CMI at these times. Despite this participants reported being just as confident to engage in HIT as they were CMI, but less confident to engage in CVI. This study highlights the utility of HIT in inactive individuals, and suggests that it may be a viable alternative to traditionally prescribed continuous modalities of exercise for promoting self-efficacy and enjoyment of exercise. PMID:25486273

  13. Use of frozen stress in extracting stress intensity factor distributions in three dimensional cracked body problems

    NASA Technical Reports Server (NTRS)

    Smith, C. W.

    1992-01-01

    The adaptation of the frozen stress photoelastic method to the determination of the distribution of stress intensity factors in three dimensional problems is briefly reviewed. The method is then applied to several engineering problems of practical significance.

  14. Intensity distribution angular shaping - Practical approach for 3D optical beamforming

    NASA Astrophysics Data System (ADS)

    Wojtanowski, Jacek; Traczyk, Maciej; Zygmunt, Marek; Mierczyk, Zygmunt; Knysak, Piotr; Drozd, Tadeusz

    2014-12-01

    We present approach of optical design which enables to obtain aspheric lens shape optimized for providing the specific light power density distribution in space. Proposed method is based on the evaluation of corresponding angular intensity distribution which can be obtained by the decomposition of the desired spatial distribution into virtual light cones set and collapsing it to the equivalent angular fingerprint. Rigorous formulas have been derived to relate refractive aspheric shape and the corresponding intensity distribution which is used for lens optimization. Algorithms of modeling and optimization were implemented in Matlab© and the calculated designs were successfully tested in Zemax environment.

  15. Intensive Versus Distributed Aphasia Therapy: A Nonrandomized, Parallel-Group, Dosage-Controlled Study.

    PubMed

    Dignam, Jade; Copland, David; McKinnon, Eril; Burfein, Penni; O'Brien, Kate; Farrell, Anna; Rodriguez, Amy D

    2015-08-01

    Most studies comparing different levels of aphasia treatment intensity have not controlled the dosage of therapy provided. Consequently, the true effect of treatment intensity in aphasia rehabilitation remains unknown. Aphasia Language Impairment and Functioning Therapy is an intensive, comprehensive aphasia program. We investigated the efficacy of a dosage-controlled trial of Aphasia Language Impairment and Functioning Therapy, when delivered in an intensive versus distributed therapy schedule, on communication outcomes in participants with chronic aphasia. Thirty-four adults with chronic, poststroke aphasia were recruited to participate in an intensive (n=16; 16 hours per week; 3 weeks) versus distributed (n=18; 6 hours per week; 8 weeks) therapy program. Treatment included 48 hours of impairment, functional, computer, and group-based aphasia therapy. Distributed therapy resulted in significantly greater improvements on the Boston Naming Test when compared with intensive therapy immediately post therapy (P=0.04) and at 1-month follow-up (P=0.002). We found comparable gains on measures of participants' communicative effectiveness, communication confidence, and communication-related quality of life for the intensive and distributed treatment conditions at post-therapy and 1-month follow-up. Aphasia Language Impairment and Functioning Therapy resulted in superior clinical outcomes on measures of language impairment when delivered in a distributed versus intensive schedule. The therapy progam had a positive effect on participants' functional communication and communication-related quality of life, regardless of treatment intensity. These findings contribute to our understanding of the effect of treatment intensity in aphasia rehabilitation and have important clinical implications for service delivery models. © 2015 American Heart Association, Inc.

  16. Note: On the wavelength dependence of the intensity calibration factor of extreme ultraviolet spectrometer determined with profile measurement of bremsstrahlung continuum

    SciTech Connect

    Yamaguchi, N.; Morita, S.; Dong, C. F.; Goto, M.; Maezawa, H.; Miyauchi, H.

    2015-06-15

    The absolute calibration factor of extreme ultraviolet spectroscopic instrument which has recently been determined from absolute radiation profile measurement of bremsstrahlung continuum has been investigated by comparing the calculated diffraction efficiency of grating. An overall tendency of the wavelength dependence of the calibration factor from 40 Å to 500 Å can be reproduced by that of the grating efficiency, especially the agreement between the measured calibration factor and the calculated grating efficiency has been found to be fairly good for the wavelength range 200 Å-500 Å.

  17. Distribution function of random strains in an elastically anisotropic continuum and defect strengths of T m3 + impurity ions in crystals with zircon structure

    NASA Astrophysics Data System (ADS)

    Malkin, B. Z.; Abishev, N. M.; Baibekov, E. I.; Pytalev, D. S.; Boldyrev, K. N.; Popova, M. N.; Bettinelli, M.

    2017-07-01

    We construct a distribution function of the strain-tensor components induced by point defects in an elastically anisotropic continuum, which can be used to account quantitatively for many effects observed in different branches of condensed matter physics. Parameters of the derived six-dimensional generalized Lorentz distribution are expressed through the integrals computed over the array of strains. The distribution functions for the cubic diamond and elpasolite crystals and tetragonal crystals with the zircon and scheelite structures are presented. Our theoretical approach is supported by a successful modeling of specific line shapes of singlet-doublet transitions of the T m3 + ions doped into AB O4 (A =Y , Lu; B =P , V) crystals with zircon structure, observed in high-resolution optical spectra. The values of the defect strengths of impurity T m3 + ions in the oxygen surroundings, obtained as a result of this modeling, can be used in future studies of random strains in different rare-earth oxides.

  18. The distribution of modified mercalli intensity in the 18 April 1906 San Francisco earthquake

    USGS Publications Warehouse

    Boatwright, J.; Bundock, H.

    2008-01-01

    We analyze Boatwright and Bundock's (2005) modified Mercalli intensity (MMI) map for the 18 April 1906 San Francisco earthquake, reviewing their interpretation of the MMI scale and testing their correlation of 1906 cemetery damage with MMI intensity. We consider in detail four areas of the intensity map where Boatwright and Bundock (2005) added significantly to the intensity descriptions compiled by Lawson (1908). We show that the distribution of off-fault damage in Sonoma County suggests that the rupture velocity approached the P-wave velocity along Tomales Bay. In contrast, the falloff of intensity with distance from the fault appears approximately constant throughout Mendocino County. The intensity in Humboldt County appears somewhat higher than the intensity in Mendocino County, suggesting that the rupture process at the northern end of the rupture was relatively energetic and that there was directivity consistent with a subsonic rupture velocity on the section of the fault south of Shelter Cove. Finally, we show that the intensity sites added in Santa Cruz County change the intensity distribution so that it decreases gradually along the southeastern section of rupture from Corralitos to San Juan Bautista and implies that the stress release on this section of rupture was relatively low.

  19. Linear intensity normalization of FP-CIT SPECT brain images using the α-stable distribution.

    PubMed

    Salas-Gonzalez, Diego; Górriz, Juan M; Ramírez, Javier; Illán, Ignacio A; Lang, Elmar W

    2013-01-15

    In this work, a linear procedure to perform the intensity normalization of FP-CIT SPECT brain images is presented. This proposed methodology is based on the fact that the histogram of intensity values can be fitted accurately using a positive skewed α-stable distribution. Then, the predicted α-stable parameters and the location-scale property are used to linearly transform the intensity values in each voxel. This transformation is performed such that the new histograms in each image have a pre-specified α-stable distribution with desired location and dispersion values. The proposed methodology is compared with a similar approach assuming Gaussian distribution and the widely used specific-to-nonspecific ratio. In this work, we show that the linear normalization method using the α-stable distribution outperforms those existing methods. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Static analysis of possible emittance growth of intense charged particle beams with thermal equilibrium distribution

    SciTech Connect

    Kikuchi, Takashi; Horioka, Kazuhiko

    2009-05-15

    Possible emittance growths of intense, nonuniform beams during a transport in a focusing channel are derived as a function of nonlinear field energy and space charge tune depression factors. The nonlinear field energy of the beam with thermal equilibrium distribution is estimated by considering the particle distribution across the cross section of the beam. The results show that the possible emittance growth can be suppressed by keeping the beam particle in thermal equilibrium distribution during the beam transport.

  1. Computing specific intensity distributions for laser material processing by solving an inverse heat conduction problem

    NASA Astrophysics Data System (ADS)

    Völl, Annika; Stollenwerk, Jochen; Loosen, Peter

    2016-03-01

    Laser beam intensity distribution profiles for material processing techniques are most of the time restricted to be either of Gaussian or tophat shape. This often leads to different kind of problems especially at the edges of the laser-heated tracks, examples are energy losses or unnecessary overlaps. Thus, machining quality and process efficiency could be much improved by using application specific intensity profiles to generate optimal temperature distributions in the processed material. In this work, we present a numerical method to derive a specific intensity profile for a given temperature distribution. As this problem belongs to the set of inverse heat conduction problems, which are ill-posed, special regularization algorithms are needed. The only method to solve this inverse problem in reasonable time is the conjugate gradient method which we extend to the given problem of laser material processing applications. This method is an iterative approach where in each step the actual temperature distribution is calculated by using the finite element method. In general, the proposed method is applicable for materials with constant or temperature dependent coefficients, for static and dynamic distributions as well as for plane or complex geometries. However, restricting ourselves to plane geometries, intensity distributions that create tophat- or stepped temperature distributions on the plane surface of the processed material are derived and will be presented. In future work, we intend to verify these results using freeform optics as well as singly addressable V(E)CSEL arrays.

  2. Spatial correlation properties and the spectral intensity distributions of focused Gaussian Schell-model array beams

    NASA Astrophysics Data System (ADS)

    Ji, Xiaoling; Pu, Zhengcai; Jia, Xinhong

    2009-07-01

    The spatial correlation properties and the spectral intensity distributions of focused Gaussian Schell-model (GSM) array beams are studied in detail. The closed-form expressions for the spectral degree of coherence and the spectral intensity of focused GSM array beams are derived. It is shown that the spectral degree of coherence of focused GSM array beams is the same as that of focused GSM beams in the focal plane. On the other hand, it is found that, in the focal plane the spectral intensity distribution of focused GSM array beams is the fringe pattern when the value of the coherence length is small. However, it becomes one peak located at the center as the value of the coherence length is large enough. In the focal plane, the spectral intensity maximum increases and the width of the normalized spectral intensity distribution decreases as the beam number increases. In general, for GSM array beams, the width of the modulus of the spectral degree of coherence in the focal plane always exceeds that of the normalized spectral intensity distribution, which is different from the behavior of focused GSM beams. In addition, the power in the bucket (PIB) and the beam propagation factor ( M2 factor) are also discussed. The main results are explained physically.

  3. Spatial distribution of marine fishes along a cross-shelf gradient containing a continuum of mangrove seagrass coral reefs off southwestern Puerto Rico

    NASA Astrophysics Data System (ADS)

    Aguilar-Perera, Alfonso; Appeldoorn, Richard S.

    2008-01-01

    Despite an extensive study of the fish community off southwestern Puerto Rico, little information is available on the fish spatial distribution along an inshore-offshore, cross-shelf gradient containing a continuum of mangrove-seagrass-coral reefs. We investigated the spatial distribution of reef-associated fish species using a stratified sampling procedure. A total of 52,138 fishes were recorded, representing 102 species belonging to 32 families. Significant differences in mean fish density were evident among strata. Mean densities at shallow fore reefs and deep fore reefs (Romero key) were significantly higher compared to the rest of strata along the gradient. Mean densities of fishes in mangroves and seagrass (Montalva Bay) were comparable to those at shallow back reefs and deep fore reefs offshore (Turrumote), but lower to those inshore (Romero); the lowest fish densities were found in mangroves and seagrass (Montalva Bay) and seagrass (Romero and Corral). At least 17 species, in 7 families, were among the most common in terms of relative abundance representing 76% of the total individuals sampled. A detrended correspondence analysis (DCA) applied to more abundant fish species showed a spatial pattern in density distribution. Three major groupings were evident corresponding to mangroves and seagrass (Montalva Bay), shallow and deep reefs (Romero), and shallow and deep reefs (Corral and Turrumote). A cluster analysis on mean fish densities of the more abundant species revealed a consistent spatial distribution according to biotope by separating the ichthyofauna associated with mangroves, seagrass and that of shallow (back and fore) reefs, and deep fore reefs.

  4. Optimal distribution of integration time for intensity measurements in Stokes polarimetry.

    PubMed

    Li, Xiaobo; Liu, Tiegen; Huang, Bingjing; Song, Zhanjie; Hu, Haofeng

    2015-10-19

    We consider the typical Stokes polarimetry system, which performs four intensity measurements to estimate a Stokes vector. We show that if the total integration time of intensity measurements is fixed, the variance of the Stokes vector estimator depends on the distribution of the integration time at four intensity measurements. Therefore, by optimizing the distribution of integration time, the variance of the Stokes vector estimator can be decreased. In this paper, we obtain the closed-form solution of the optimal distribution of integration time by employing Lagrange multiplier method. According to the theoretical analysis and real-world experiment, it is shown that the total variance of the Stokes vector estimator can be significantly decreased about 40% in the case discussed in this paper. The method proposed in this paper can effectively decrease the measurement variance and thus statistically improves the measurement accuracy of the polarimetric system.

  5. Optimal distribution of integration time for intensity measurements in degree of linear polarization polarimetry.

    PubMed

    Li, Xiaobo; Hu, Haofeng; Liu, Tiegen; Huang, Bingjing; Song, Zhanjie

    2016-04-04

    We consider the degree of linear polarization (DOLP) polarimetry system, which performs two intensity measurements at orthogonal polarization states to estimate DOLP. We show that if the total integration time of intensity measurements is fixed, the variance of the DOLP estimator depends on the distribution of integration time for two intensity measurements. Therefore, by optimizing the distribution of integration time, the variance of the DOLP estimator can be decreased. In this paper, we obtain the closed-form solution of the optimal distribution of integration time in an approximate way by employing Delta method and Lagrange multiplier method. According to the theoretical analyses and real-world experiments, it is shown that the variance of the DOLP estimator can be decreased for any value of DOLP. The method proposed in this paper can effectively decrease the measurement variance and thus statistically improve the measurement accuracy of the polarimetry system.

  6. Angular distribution of electrons directly accelerated by an intense tightly focused laser pulse

    NASA Astrophysics Data System (ADS)

    Vais, O. E.; Bochkarev, S. G.; Ter-Avetisyan, S.; Bychenkov, V. Yu.

    2017-02-01

    We report a study of spectral and angular distributions of electrons directly accelerated from an ultrathin nanofoil by a tightly focused, relativistically intense laser pulse. The approach applied is based on a realistic model describing the focusing of radiation by an off-axis parabolic mirror, the field distribution being simulated with the help of Stratton – Chu integrals. We have compared spectral and angular electron distributions for laser pulses having Gaussian transverse and rectangular intensity profiles on the mirror at the same laser pulse energy. It is shown that in the case of a pulse with a rectangular intensity profile, the energy of fast electrons is higher and the emission angles are smaller than those in the case of a pulse with a Gaussian profile. Presented at ECLIM2016 (Moscow, 18 – 23 September 2016).

  7. The Column Density Distribution and Continuum Opacity of the Intergalactic and Circumgalactic Medium at Redshift langzrang = 2.4

    NASA Astrophysics Data System (ADS)

    Rudie, Gwen C.; Steidel, Charles C.; Shapley, Alice E.; Pettini, Max

    2013-06-01

    We present new high-precision measurements of the opacity of the intergalactic and circumgalactic medium (IGM; CGM) at langzrang = 2.4. Using Voigt profile fits to the full Lyα and Lyβ forests in 15 high-resolution high-S/N spectra of hyperluminous QSOs, we make the first statistically robust measurement of the frequency of absorbers with H I column densities 14 \\lesssim log (N_H\\,\\scriptsize{ I}/ {cm}^{-2}) \\lesssim 17.2. We also present the first measurements of the frequency distribution of H I absorbers in the volume surrounding high-z galaxies (the CGM, 300 pkpc), finding that the incidence of absorbers in the CGM is much higher than in the IGM. In agreement with Rudie et al., we find that there are fractionally more high-N H I absorbers than low-N H I absorbers in the CGM compared to the IGM, leading to a shallower power law fit to the CGM frequency distribution. We use these new measurements to calculate the total opacity of the IGM and CGM to hydrogen-ionizing photons, finding significantly higher opacity than most previous studies, especially from absorbers with log (N_H\\,\\scriptsize{ I}/ {cm}^{-2}) < 17.2. Reproducing the opacity measured in our data as well as the incidence of absorbers with log (N_H\\,\\scriptsize{ I}/ {cm}^{-2}) \\gt 17.2 requires a broken power law parameterization of the frequency distribution with a break near N H I ≈1015 cm-2. We compute new estimates of the mean free path (λmfp) to hydrogen-ionizing photons at z em = 2.4, finding λmfp = 147 ± 15 Mpc when considering only IGM opacity. If instead, we consider photons emanating from a high-z star-forming galaxy and account for the local excess opacity due to the surrounding CGM of the galaxy itself, the mean free path is reduced to λmfp = 121 ± 15 Mpc. These λmfp measurements are smaller than recent estimates and should inform future studies of the metagalactic UV background and of ionizing sources at z ≈ 2-3. Based on data obtained at the W. M. Keck Observatory

  8. Mapping the continuous reciprocal space intensity distribution of X-ray serial crystallography.

    PubMed

    Yefanov, Oleksandr; Gati, Cornelius; Bourenkov, Gleb; Kirian, Richard A; White, Thomas A; Spence, John C H; Chapman, Henry N; Barty, Anton

    2014-07-17

    Serial crystallography using X-ray free-electron lasers enables the collection of tens of thousands of measurements from an equal number of individual crystals, each of which can be smaller than 1 µm in size. This manuscript describes an alternative way of handling diffraction data recorded by serial femtosecond crystallography, by mapping the diffracted intensities into three-dimensional reciprocal space rather than integrating each image in two dimensions as in the classical approach. We call this procedure 'three-dimensional merging'. This procedure retains information about asymmetry in Bragg peaks and diffracted intensities between Bragg spots. This intensity distribution can be used to extract reflection intensities for structure determination and opens up novel avenues for post-refinement, while observed intensity between Bragg peaks and peak asymmetry are of potential use in novel direct phasing strategies.

  9. Sound radiation from an infinite elastic cylinder with dual-wave propagation-intensity distributions

    NASA Technical Reports Server (NTRS)

    Fuller, C. R.

    1988-01-01

    The radiation of sound from an elastic cylindrical shell filled with fluid and supporting multiwave propagation is studied analytically. Combinations of supersonic and subsonic shell waves are considered. The radiated field is mapped by using acoustic intensity vectors evaluated at various locations. Both time averaged and instantaneous intensity are investigated. The acoustic intensity is seen to vary markedly with axial distance down the cylinder. The effect is shown to be associated with cross terms in the intensity relations, and its magnitude and location to depend upon the relative phase and amplitudes of individual waves. Subsonic shell waves are demonstrated to interact strongly with supersonic shell waves to cause a large modification in the radiated intensity distributions near the shell surface.

  10. HOT ELECTRON ENERGY DISTRIBUTIONS FROM ULTRA-INTENSE LASER SOLID INTERACTIONS

    SciTech Connect

    Chen, H; Wilks, S C; Kruer, W L; Moon, S; Patel, N; Patel, P K; Shepherd, R; Snavely, R

    2005-12-08

    We present experimental data of electron energy distributions from ultra-intense (>10{sup 19} W/cm{sup 2}) laser-solid interactions using the Rutherford Appleton Laboratory Vulcan petawatt laser. These measurements were made using a CCD-based magnetic spectrometer. We present details on the distinct effective temperatures that were obtained for a wide variety of targets as a function of laser intensity. It is found that as the intensity increases from 10{sup 17} W/cm{sup 2} to 10{sup 19} W/cm{sup 2}, a 0.4 dependence on the laser intensity is found. Between 10{sup 19} W/cm{sup 2} and 10{sup 20} W/cm{sup 2}, a gradual rolling off of temperature with intensity is observed.

  11. A 6-month analysis of training-intensity distribution and physiological adaptation in Ironman triathletes.

    PubMed

    Neal, Craig M; Hunter, Angus M; Galloway, Stuart D R

    2011-11-01

    In the present study, we analysed the training-intensity distribution and physiological adaptations over a 6-month period preceding an Ironman triathlon race. Ten athletes (mean ± s: age 43 ± 3 years, mass 78.3 ± 10.3 kg, stature 1.79 ± 0.05 m) participated in the study. The study consisted of three training periods (A, B, C), each of approximately 2 months' duration, and four testing weeks. Testing consisted of incremental tests to exhaustion for swimming, cycling and running, and assessments for anthropometry plus cardiovascular and pulmonary measures. The lactate threshold and the lactate turnpoint were used to demarcate three discipline-specific, exercise-intensity zones. The mean percentage of time spent in zones 1, 2, and 3 was 69 ± 9%, 25 ± 8%, and 6 ± 2% for periods A-C combined. Only modest physiological adaptation occurred throughout the 6-month period, with small to moderate effect sizes at best. Relationships between the training volume/training load and the training-intensity distribution with the changes in key measures of adaptation were weak and probably reflect differences in initial training status. Our results suggest that the effects of intensity distribution are small over short-term training periods and future experimental research is needed to clarify the potential impact of intensity distribution on physiological adaptation.

  12. A precise Boltzmann distribution law for the fluorescence intensity ratio of two thermally coupled levels

    NASA Astrophysics Data System (ADS)

    Qin, Feng; Zhao, Hua; Cai, Wei; Zhang, Zhiguo; Cao, Wenwu

    2016-06-01

    Noncontact monitoring temperature is very important in modern medicine, science, and technologies. The fluorescence intensity ratio (FIR) technique based on the Boltzmann distribution law exhibits excellent application potential, but the observed FIR deviates from the Boltzmann distribution law in the low temperature range. We propose a fluorescence intensity ratio relation FIR* = ηFIR by introducing a quantity η representing thermal population degree, which can be obtained from measured fluorescence decay curves of the upper emitting level. Using Eu3+ as an example, the method is confirmed that the deviated FIR is able to be corrected and return to follow the Boltzmann law.

  13. Light fields with an axially expanded intensity distribution for stable three-dimensional optical trapping.

    PubMed

    Zwick, Susanne; Schaub, Christian; Haist, Tobias; Osten, Wolfgang

    2010-09-13

    We introduce a new kind of light field to improve and simplify the trapping process of axially displaced particles. To this end we employ a light field with an axially expanded intensity distribution, which at the same time enables stable axial trapping. We present simulations of the axial intensity distribution of the novel trapping field and first experimental results, which demonstrate the improvement of the reliability of the axial trapping process. The method can be used to automate trapping of particles that are located outside of the focal plane of the microscope.

  14. The model about the package structure of LED and the light intensity distribution

    NASA Astrophysics Data System (ADS)

    Sun, Haojie; Li, Mengyuan; Zhuang, Jie; Zhang, Dawei

    2014-11-01

    Base on the principles of the LED package structure and the LED optical model, we use Tracepro to do the simulation of LED devices. By changing the parameters of LED model, such as the package structure, the size of reflective cup, the height of chip and the angle of the reflective bowl, etc. We simulate the light intensity distribution curve of LED in different structures and find different results. That is a bigger height, a lager angle and a smaller curvature will make a better condenser effect. Compare with measurement data which shows that intensity distribution abide by some laws. Those conclusions can be used in guiding the package structure design of LEDs.

  15. Second-order Compton-Getting effect on arbitrary intensity distribution

    NASA Technical Reports Server (NTRS)

    Ng, C. K.

    1985-01-01

    Theoretical studies of energetic particles in space are often referred to a special frame of reference. To compare theory with experiment, one has to transform the particle distribution from the special frame to the observer's frame, or vice versa. Various methods have been derived to obtain the directional distribution in the comoving frame from the directional fluxes measured on a spacecraft. These methods have become progressively complicated as increasingly detailed directional particle data become available. A set of 2nd order correct formulae for the transformation of an arbitrary differential intensity distribution, expressed as a series of spherical harmonics, between any two frames in constant relative motion is presented. These formulae greatly simplify the complicated procedures currently in use for the determination of the differential intensity distribution in a comoving frame.

  16. Small-scale Intensity Mapping: Extended Lyα, Hα, and Continuum Emission as a Probe of Halo Star Formation in High-redshift Galaxies

    NASA Astrophysics Data System (ADS)

    Mas-Ribas, Lluís; Dijkstra, Mark; Hennawi, Joseph F.; Trenti, Michele; Momose, Rieko; Ouchi, Masami

    2017-05-01

    Lyα halos are observed ubiquitously around star-forming galaxies at high redshift, but their origin is still a matter of debate. We demonstrate that the emission from faint unresolved satellite sources, {M}{UV}≳ -17, clustered around the central galaxies may play a major role in generating spatially extended Lyα, continuum (UV + VIS), and Hα halos. We apply the analytic formalism developed in Mas-Ribas & Dijkstra to model the halos around Lyman Alpha Emitters (LAEs) at z = 3.1, for several different satellite clustering prescriptions. In general, our UV and Lyα surface brightness profiles match the observations well at 20≲ r≲ 40 physical kpc from the centers of LAEs. We discuss how our profiles depend on various model assumptions and how these can be tested and constrained with future Hα observations by the James Webb Space Telescope (JWST). Our analysis shows how spatially extended halos constrain (i) the presence of otherwise undetectable satellite sources, (ii) the integrated, volumetric production rates of Lyα and LyC photons, and (iii) their population-averaged escape fractions. These quantities are all directly relevant for understanding galaxy formation and evolution and, for high enough redshifts, cosmic reionization.

  17. Ash Dispersal in Planetary Atmospheres: Continuum vs. Non-continuum Effects

    NASA Astrophysics Data System (ADS)

    Fagents, S. A.; Baloga, S. M.; Glaze, L. S.

    2013-12-01

    The dispersal of ash from a volcanic vent on any given planet is dictated by particle properties (density, shape, and size distribution), the intensity of the eruptive source, and the characteristics of the planetary environment (atmospheric structure, wind field, and gravity) into which the ash is erupted. Relating observations of potential pyroclastic deposits to source locations and eruption conditions requires a detailed quantitative understanding of the settling rates of individual particles under changing ambient conditions. For atmospheres that are well described by continuum mechanics, the conventional Newtonian description of particle motion allows particle settling velocities to be related to particle characteristics via a drag coefficient. However, under rarefied atmospheric conditions (i.e., on Mars and at high altitude on Earth), non-continuum effects become important for ash-sized particles, and an equation of motion based on statistical mechanics is required for calculating particle motion. We have developed a rigorous new treatment of particle settling under variable atmospheric conditions and applied it to Earth and Mars. When non-continuum effects are important (as dictated by the mean free path of atmospheric gas relative to the particle size), fall velocities are greater than those calculated by continuum mechanics. When continuum conditions (i.e., higher atmospheric densities) are reached during descent, our model switches to a conventional formulation that determines the appropriate drag coefficient as the particle transits varying atmospheric properties. The variation of settling velocity with altitude allows computation of particle trajectories, fall durations and downwind dispersal. Our theoretical and numerical analyses show that several key, competing factors strongly influence the downwind trajectories of ash particles and the extents of the resulting deposits. These factors include: the shape of the particles (non-spherical particles

  18. A Study on Inhomogeneous Neutron Intensity Distribution Origin from Neutron Guide Transportation

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Wei, Guohai; Wang, Hongli; Liu, Yuntao; He, Linfeng; Sun, Kai; Han, Songbai; Chen, Dongfeng

    The uniformity of the neutron intensity spatial distribution at the sample position will directly affect the neutron imaging quality. But the unexpected inhomogeneous spatial distribution phenomenon always appears in the neutron radiography facilities installed at the end of neutron guide. In this paper, the source of this phenomenon has been analyzed through geometrical optics and confirmed by Monte Carlo simulations, and several optimization solutions are also proposed.

  19. Kilometric Continuum Radiation

    NASA Technical Reports Server (NTRS)

    Green, James L.; Boardsen, Scott

    2006-01-01

    Kilometric continuum (KC) is the high frequency component (approximately 100 kHz to approximately 800 kHz) of nonthermal continuum (NTC). Unlike the lower frequency portion of NTC (approximately 5 kHz to approximately 100 kHz) whose source is around the dawn sector, the source of KC occurs at all magnetic local times. The latitudinal beaming of KC as observed by GEOTAIL is, for most events, restricted to plus or minus 15 degrees magnetic latitude. KC has been observed during periods of both low and strong geomagnetic activity, with no significant correlation of wave intensity with K(sub p), index. However statistically the maximum observed frequency of KC emission tends to increase with K(sub p) index, the effect is more pronounced around solar maximum, but is also detected near solar minimum. There is strong evidence that the source region of KC is from the equatorial plasmapause during periods when a portion of the plasmapause moves significantly inwards from its nominal position. Case studies have shown that KC emissions are nearly always associated with plasmaspheric notches, shoulders, and tails. There is a recent focus on trying to understand the banded frequency structure of this emission and its relationship to plasmaspheric density ducts and irregularities in the source region.

  20. The Influence of Soil Moisture and Wind on Rainfall Distribution and Intensity in Florida

    NASA Technical Reports Server (NTRS)

    Baker, R. David; Lynn, Barry H.; Boone, Aaron; Tao, Wei-Kuo

    1998-01-01

    Land surface processes play a key role in water and energy budgets of the hydrological cycle. For example, the distribution of soil moisture will affect sensible and latent heat fluxes, which in turn may dramatically influence the location and intensity of precipitation. However, mean wind conditions also strongly influence the distribution of precipitation. The relative importance of soil moisture and wind on rainfall location and intensity remains uncertain. Here, we examine the influence of soil moisture distribution and wind distribution on precipitation in the Florida peninsula using the 3-D Goddard Cumulus Ensemble (GCE) cloud model Coupled with the Parameterization for Land-Atmosphere-Cloud Exchange (PLACE) land surface model. This study utilizes data collected on 27 July 1991 in central Florida during the Convection and Precipitation Electrification Experiment (CaPE). The idealized numerical experiments consider a block of land (the Florida peninsula) bordered on the east and on the west by ocean. The initial soil moisture distribution is derived from an offline PLACE simulation, and the initial environmental wind profile is determined from the CaPE sounding network. Using the factor separation technique, the precise contribution of soil moisture and wind to rainfall distribution and intensity is determined.

  1. High-speed imaging system of luminous intensity distribution of plasma using light emission CT

    NASA Astrophysics Data System (ADS)

    Kawamura, Hirofumi; Saito, Hideo; Yuasa, Kunio; Yuge, Youji; Nakajima, Masato

    1995-02-01

    The authors developed a light emission computed tomography (LECT) system for plasma diagnosis supporting the high speed data collection function. In this paper, we describe the principles of the system and experiments in reconstructing the luminous intensity distribution of plasma in a discharge tube with the system.

  2. Inverse identification of intensity distributions from multiple flux maps in concentrating solar applications

    NASA Astrophysics Data System (ADS)

    Erickson, Ben; Petrasch, Jörg

    2012-06-01

    Radiative flux measurements at the focal plane of solar concentrators are typically performed using digital cameras in conjunction with Lambertian targets. To accurately predict flux distributions on arbitrary receiver geometries directional information about the radiation is required. Currently, the directional characteristics of solar concentrating systems are predicted via ray tracing simulations. No direct experimental technique to determine intensities of concentrating solar systems is available. In the current paper, multiple parallel flux measurements at varying distances from the focal plane together with a linear inverse method and Tikhonov regularization are used to identify the directional and spatial intensity distribution at the solution plane. The directional binning feature of an in-house Monte Carlo ray tracing program is used to provide a reference solution. The method has been successfully applied to two-dimensional concentrators, namely parabolic troughs and elliptical troughs using forward Monte Carlo ray tracing simulations that provide the flux maps as well as consistent, associated intensity distribution for validation. In the two-dimensional case, intensity distributions obtained from the inverse method approach the Monte Carlo forward solution. In contrast, the method has not been successful for three dimensional and circular symmetric concentrator geometries.

  3. Analysis of equi-intensity curves and NU distribution of EAS

    NASA Astrophysics Data System (ADS)

    Tanahashi, G.

    1985-08-01

    The distribution of the number of muons in extensive air showers (EAS) and the equi-intensity curves of EAS are analyzed on the basis of Monte Carlo simulation of various cosmic ray composition and the interaction models. Problems in the two best combined models are discussed.

  4. Enhanced Intensity Distribution Analysis of the Rotational-Vibrational Spectrum of HCl

    ERIC Educational Resources Information Center

    Fetterolf, Monty L.

    2007-01-01

    The use of generated intensity distributions as overlays on the HCl rotational-vibrational FTIR spectrum is presented as an effective method to integrate lab work into the physical chemistry lecture. The overlays that best match the actual HCl spectrum are generated using a pre-exponential factor of 2J+2.

  5. Applying micro genetic algorithm to numerical model for luminous intensity distribution of planar prism LED luminaire

    NASA Astrophysics Data System (ADS)

    Kim, Yu-Sin; Choi, An-Seop; Jeong, Jae-Weon

    2013-04-01

    Several technological problems have to be resolved for LED to be used as a general purpose light source. For instance, LED luminaires have a property of high luminance due to a narrow beam angle and a small volume compared to general light sources. There are several differences between existing luminaires and the intensity distribution of an LED luminaire. An optical engineer has the challenging problem of designing a spatially extended and non-uniform light source. It is difficult for LED luminaires to obtain the target luminous intensity distribution required in a space, because the design process requires much trial and error. And the process also requires much design time. In this study, an optimization algorithm of a numerical model for luminous intensity distribution of planar LED luminaires was developed to find optimized prism angles. This algorithm would used the micro genetic algorithm technique which is the improved form of genetic algorithms. Also, this algorithm is capable of deriving the optimized angle of a prism to achieve the target luminous intensity distribution of planar prism LED luminaires. Therefore, the purpose of this study is to introduce a numerical model of a planar prism LED luminaire and to develop a optimization algorithm that is able to find an optimum luminaire optical design solution using the micro genetic algorithm.

  6. Pedagogical Implications of Score Distribution Pattern and Learner Satisfaction in an Intensive TOEIC Course

    ERIC Educational Resources Information Center

    Kang, Che Chang

    2014-01-01

    The study aimed at investigating TOEIC score distribution patterns and learner satisfaction in an intensive TOEIC course and drew implications for pedagogical practice. A one-group pre-test post-test experiment and a survey on learner satisfaction were conducted on Taiwanese college EFL students (n = 50) in a case study. Results showed that the…

  7. Decoy-state quantum key distribution with large random errors of light intensity

    NASA Astrophysics Data System (ADS)

    Wang, Xiang-Bin

    2007-05-01

    We show how to do decoy-state quantum key distribution efficiently with large random errors in the intensity control. We present a theorem for efficiently calculating the lower bound of single-photon counts with many undetermined parameters. In the calculation of the single-photon counts of our protocol, the linear terms of the intensity fluctuation disappear and only the quadratic terms take effect. Given that the intensity fluctuation is upper bounded by ±5% , ±10% , and ±15% , the verified lower bound of the percentage of untagged bits from our protocol is as large as 99.7%, 99.0%, and 97.9% of that from an ideal protocol where the light intensity is exactly controlled.

  8. Effect of training intensity distribution on aerobic fitness variables in elite soccer players: a case study.

    PubMed

    Castagna, Carlo; Impellizzeri, Franco M; Chaouachi, Anis; Bordon, Claudio; Manzi, Vincenzo

    2011-01-01

    The aim of this article was to quantify the distribution of training intensities and its effect on aerobic fitness in professional elite soccer players. Fourteen professional soccer players were observed during the prechampionship training period (6 weeks). Treadmill running speed and heart rates (HRs) at 2 and 4 mmol · L(-1) blood-lactate concentrations were assessed pre and posttraining. Training intensities were categorized using 3 HR zones: low intensity (


    intensity (between HR 2 and 4 mmol · L(-1)), and high intensity (>HR 4 mmol · L(-1)). Analysis of the 504 individual training sessions showed that 73 ± 2.5, 19 ± 2.8, and 8 ± 1.4% of the total training time was spent at low, moderate, and high intensity, respectively (p < 0.001). Speed at 2 and 4 mmol · L(-1) significantly improved posttraining (5 and 7%, respectively, p < 0.01). Training spent at high intensity was significantly related to relative speed improvements at 2 mmol · L(-1) (r = 0.84, p < 0.001;) and 4 mmol · L(-1) (r = 0.65, p = 0.001). Players spent almost two-thirds of their training time at low intensities. However, only the time spent at high intensity (>90% of maximal HR) was related to changes in aerobic fitness. These results support the usefulness of the quantification of aerobic training load using HR. Furthermore, it stresses the effectiveness of the high-intensity training in soccer.

  9. A Network-Aware Distributed Storage Cache for Data Intensive Environments

    SciTech Connect

    Tierney, B.L.; Lee, J.R.; Johnston, W.E.; Crowley, B.; Holding, M.

    1999-12-23

    Modern scientific computing involves organizing, moving, visualizing, and analyzing massive amounts of data at multiple sites around the world. The technologies, the middleware services, and the architectures that are used to build useful high-speed, wide area distributed systems, constitute the field of data intensive computing. In this paper the authors describe an architecture for data intensive applications where they use a high-speed distributed data cache as a common element for all of the sources and sinks of data. This cache-based approach provides standard interfaces to a large, application-oriented, distributed, on-line, transient storage system. They describe their implementation of this cache, how they have made it network aware, and how they do dynamic load balancing based on the current network conditions. They also show large increases in application throughput by access to knowledge of the network conditions.

  10. Structural intensity in plates with multiple discrete and distributed spring-dashpot systems

    NASA Astrophysics Data System (ADS)

    Khun, M. S.; Lee, H. P.; Lim, S. P.

    2004-09-01

    The finite element method has been used to predict the structural intensity of a plate with multiple discrete and distributed dampers. Different combinations of dampers in different positions were employed to study the effects of multiple dampers in an individual plate model to examine the energy flow phenomenon in the presence of many dissipative elements. The structural intensity of plate structures connected by loosened bolts subjected to forced excitation is also presented in this paper. The loosened bolts are modelled by discrete as well as distributed spring-dashpot systems. The distributed springs and dampers are introduced to characterize the joint behavior of the plates. Numerical results are also presented for the plates connected by two bolts.

  11. Intensity distribution in cylindrical-circular receivers for nonperfect cylindrical-parabolic concentrators

    SciTech Connect

    Nicols, R.O.

    1985-08-15

    A 2-D optical analysis is described that allows determination of the intensity distribution on a circular cylinder located in the focal zone of nonperfect concentrators. We call nonperfect concentrators those in which the normal to each differential element of the specular surface departs from its correct position by an angle epsilon, the possible values of which follow a Gaussian distribution of mean value epsilon-bar and standard deviation sigma. The analysis is based on a previous one developed to calculate the intensity distribution at the receiver plane of nonperfect cylindrical concentrators. The analysis permits the consideration of circular receivers displaced from the focus by distance delta/sub f/ in any direction and directions of the incident rays nonparallel to the parabola's symmetry plane. Results for different sets of parameters characterizing the behavior of a given concentrator are shown and compared.

  12. A compound detector array for the measurement of large area laser beam intensity distribution

    NASA Astrophysics Data System (ADS)

    Wang, Fei; Xie, Yongjie; Ji, Yunfeng; Duan, Liuhua; Ye, Xisheng

    2013-05-01

    A synthesis of the calorimetric and photoelectric method on the high energy laser beams measurement is presented. Data fusion of the two kinds of detector units is achieved with real-time scaling onsite. A set of compound diagnostic system is developed for the large area laser beam intensity distribution measurement, which is mainly composed of 256 calorimetric detectors, 120 photoelectric detectors, multi-channel data sampling module and one central processing computer. The total energy of the laser beam is accurately measured with calorimetric detectors, and the spatial intensity distribution with high temporal resolution is given by the photoelectric detectors. With the merits of energy accuracy and the temporal resolution based on the two kinds of detector units, the compound diagnostic system can be used to measure accurately the far-field temporal and spatial distribution of high energy laser beams.

  13. Submillimeter Continuum Observations of Comets

    NASA Technical Reports Server (NTRS)

    Jewitt, David

    1998-01-01

    The aim of this proposal was to study the submillimeter continuum emission from comets. The study was based mainly on the exploitation of the world's leading submillimeter telescope, the JCMT (James Clerk Maxwell Telescope) on Mauna Kea. Submillimeter wavelengths provide a unique view of cometary physics for one main reason. The cometary size distribution is such that the scattering cross-section is dominated by small dust grains, while the mass is dominated by the largest particles. Submillimeter continuum radiation samples cometary particles much larger than those sampled by more common observations at shorter (optical and infrared) wavelengths and therefore provides a nearly direct measure of the cometary dust mass.

  14. Effects of land-use intensity on arthropod species abundance distributions in grasslands.

    PubMed

    Simons, Nadja K; Gossner, Martin M; Lewinsohn, Thomas M; Lange, Markus; Türke, Manfred; Weisser, Wolfgang W

    2015-01-01

    As a rule, communities consist of few abundant and many rare species, which is reflected in the characteristic shape of species abundance distributions (SADs). The processes that shape these SADs have been a longstanding problem for ecological research. Although many studies found strong negative effects of increasing land-use intensity on diversity, few reports consider land-use effects on SADs. Arthropods (insects and spiders) were sampled on 142 grassland plots in three regions in Germany, which were managed with different modes (mowing, fertilization and/or grazing) and intensities of land use. We analysed the effect of land use on three parameters characterizing the shape of SADs: abundance decay rate (the steepness of the rank abundance curve, represented by the niche-preemption model parameter), dominance (Berger-Parker dominance) and rarity (Fisher's alpha). Furthermore, we tested the core-satellite hypothesis by comparing the species' rank within the SAD to their distribution over the land-use gradient. When data on Araneae, Cicadina, Coleoptera, Heteroptera and Orthoptera were combined, abundance decay rate increased with combined land-use intensity (including all modes). Among the single land-use modes, increasing fertilization and grazing intensity increased the decay rate of all taxa, while increasing mowing frequency significantly affected the decay rate only in interaction with fertilization. Results of single taxa differed in their details, but all significant interaction effects included fertilization intensity. Dominance generally increased with increasing fertilization and rarity decreased with increasing grazing or mowing intensity, despite small differences among taxa and regions. The majority of species found on <10% of the plots per region were generally rare (<10 individuals), which is in accordance with the core-satellite hypothesis. We found significant differences in the rarity and dominance of species between plots of low and high

  15. Anomalous photoelectron angular distribution in ionization of Kr in intense ultraviolet laser fields

    NASA Astrophysics Data System (ADS)

    Nakano, Motoyoshi; Otobe, Tomohito; Itakura, Ryuji

    2017-06-01

    We investigate multiphoton ionization of Kr for the formation of the two spin-orbit split states 1/2 2P and 3/2 2P of Kr+ in intense ultraviolet femtosecond laser fields (λ ≈ 398 nm, τ ≈ 50 fs). As the laser intensity increases from 8 to 39 TW cm-2, the photoelectron angular distribution (PAD) exhibits the anomalous enhancement in the direction perpendicular to the laser polarization. With the support of the time-dependent density functional theory taking account of the spin-orbit interaction, the measured anomalous PAD is ascribed to the autoionization to 3/2 2P.

  16. Tennis Play Intensity Distribution and Relation with Aerobic Fitness in Competitive Players

    PubMed Central

    Baiget, Ernest; Fernández-Fernández, Jaime; Iglesias, Xavier; Rodríguez, Ferran A.

    2015-01-01

    The aims of this study were (i) to describe the relative intensity of simulated tennis play based on the cumulative time spent in three metabolic intensity zones, and (ii) to determine the relationships between this play intensity distribution and the aerobic fitness of a group of competitive players. 20 male players of advanced to elite level (ITN) performed an incremental on-court specific endurance tennis test to exhaustion to determine maximal oxygen uptake (VO2max) and the first and second ventilatory thresholds (VT1, VT2). Ventilatory and gas exchange parameters were monitored using a telemetric portable gas analyser (K4 b2, Cosmed, Rome, Italy). Two weeks later the participants played a simulated tennis set against an opponent of similar level. Intensity zones (1: low, 2: moderate, and 3: high) were delimited by the individual VO2 values corresponding to VT1 and VT2, and expressed as percentage of maximum VO2 and heart rate. When expressed relative to VO2max, percentage of playing time in zone 1 (77 ± 25%) was significantly higher (p < 0.001) than in zone 2 (20 ± 21%) and zone 3 (3 ± 5%). Moderate to high positive correlations were found between VT1, VT2 and VO2max, and the percentage of playing time spent in zone 1 (r = 0.68–0.75), as well as low to high inverse correlations between the metabolic variables and the percentage of time spent in zone 2 and 3 (r = -0.49–0.75). Players with better aerobic fitness play at relatively lower intensities. We conclude that players spent more than 75% of the time in their low-intensity zone, with less than 25% of the time spent at moderate to high intensities. Aerobic fitness appears to determine the metabolic intensity that players can sustain throughout the game. PMID:26098638

  17. Transfrontier macroseismic data exchange in NW Europe: examples of non-circular intensity distributions

    NASA Astrophysics Data System (ADS)

    Van Noten, Koen; Lecocq, Thomas; Hinzen, Klaus-G.; Sira, Christophe; Camelbeeck, Thierry

    2016-04-01

    Macroseismic data acquisition recently received a strong increase in interest due to public crowdsourcing through internet-based inquiries and real-time smartphone applications. Macroseismic analysis of felt earthquakes is important as the perception of people can be used to detect local/regional site effects in areas without instrumentation. We will demonstrate how post-processing macroseismic data improves the quality of real-time intensity evaluation of new events. Instead of using the classic DYFI representation in which internet intensities are averaged per community, we, first, geocoded all individual responses and structure the model area into 100 km2grid cells. Second, the average intensity of all answers within a grid cell is calculated. The resulting macroseismic grid cell distribution shows a less subjective and more homogeneous intensity distribution than the classical irregular community distribution and helps to improve the calculation of intensity attenuation functions. In this presentation, the 'Did You Feel It' (DYFI) macroseismic data of several >M4, e.g. the 2002 ML 4.9 Alsdorf and 2011 ML 4.3 Goch (Germany) and the 2015 ML 4.1 Ramsgate (UK), earthquakes felt in Belgium, Germany, The Netherlands, France, Luxemburg and UK are analysed. Integration of transfrontier DYFI data of the ROB-BNS, KNMI, BCSF and BGS networks results in a particular non-circular, distribution of the macroseismic data in which the felt area for all these examples extends significantly more in E-W than N-S direction. This intensity distribution cannot be explained by geometrical amplitude attenuation alone, but rather illustrates a low-pass filtering effect due to the south-to-north increasing thickness of cover sediments above the London-Brabant Massif. For the studied M4 to M5 earthquakes, the thick sediments attenuate seismic energy at higher frequencies and consequently less people feel the vibrations at the surface. This example of successful macroseismic data exchange

  18. Measurements of the distribution of sound source intensities in turbulent jets.

    NASA Technical Reports Server (NTRS)

    Grosche, F.-R.; Jones, J. H.; Wilhold, G. A.

    1973-01-01

    The spatial distribution of sound source intensities in jets is determined from the sound radiated into the acoustic far field by means of a concave mirror-microphone system. The mirror forms an image of the sound sources in a region far enough from the jet so that near field pressure fluctuations can be neglected. The sound intensity in the image is thus closely related to the strength of the actual sound sources in the jet. Results of measurements with jets of Mach numbers 0.7 to 1.9 emanating from circular nozzles and from slot nozzle-flap combinations demonstrate the influence of Mach number and of other parameters upon the sound source distribution.

  19. A coordinate transformation method for calculating the 3D light intensity distribution in ICF hohlraum

    NASA Astrophysics Data System (ADS)

    Lin, Zhili; Li, Xiaoyan; Zhao, Kuixia; Chen, Xudong; Chen, Mingyu; Pu, Jixiong

    2016-06-01

    For an inertial confinement fusion (ICF) system, the light intensity distribution in the hohlraum is key to the initial plasma excitation and later laser-plasma interaction process. Based on the concept of coordinate transformation of spatial points and vector, we present a robust method with a detailed procedure that makes the calculation of the three dimensional (3D) light intensity distribution in hohlraum easily. The method is intuitive but powerful enough to solve the complex cases of random number of laser beams with arbitrary polarization states and incidence angles. Its application is exemplified in the Shenguang III Facility (SG-III) that verifies its effectiveness and it is useful for guiding the design of hohlraum structure parameter.

  20. Acoustic energy density distribution and sound intensity vector field inside coupled spaces.

    PubMed

    Meissner, Mirosław

    2012-07-01

    In this paper, the modal expansion method supported by a computer implementation has been used to predict steady-state distributions of the potential and kinetic energy densities, and the active and reactive sound intensities inside two coupled enclosures. The numerical study was dedicated to low-frequency room responses. Calculation results have shown that the distribution of energetic quantities in coupled spaces is strongly influenced by the modal localization. Appropriate descriptors of the localization effect were introduced to identify localized modes. As was evidenced by numerical data, the characteristic objects in the active intensity field are vortices positioned irregularly inside the room. It was found that vortex centers lie exactly on the lines corresponding to zeros of the eigenfunction for a dominant mode. Finally, an impact of the wall impedance on the quantitative relationship between the active and reactive intensities was analyzed and it was concluded that for very small sound damping the behavior of the sound intensity inside the room space is essentially only oscillatory.

  1. Spatial distribution of the intensity noise of a vertical-cavity surface-emitting semiconductor laser.

    PubMed

    Bramati, A; Hermier, J P; Khoury, A Z; Giacobino, E; Schnitzer, P; Michalzik, R; Ebeling, K J; Poizat, J P; Grangier, P

    1999-07-01

    We studied anticorrelated quantum fluctuations between the TEM(00) and the TEM(01) transverse modes of a vertical-cavity surface-emitting semiconductor laser by measuring the transverse spatial distribution of the laser beam intensity noise. Our experimental results are found to be in good agreement with the predictions of a phenomenological model that accounts for quantum correlations between transverse modes in a light beam.

  2. Intensity distribution of the x ray source for the AXAF VETA-I mirror test

    NASA Technical Reports Server (NTRS)

    Zhao, Ping; Kellogg, Edwin M.; Schwartz, Daniel A.; Shao, Yibo; Fulton, M. Ann

    1992-01-01

    The X-ray generator for the AXAF VETA-I mirror test is an electron impact X-ray source with various anode materials. The source sizes of different anodes and their intensity distributions were measured with a pinhole camera before the VETA-I test. The pinhole camera consists of a 30 micrometers diameter pinhole for imaging the source and a Microchannel Plate Imaging Detector with 25 micrometers FWHM spatial resolution for detecting and recording the image. The camera has a magnification factor of 8.79, which enables measuring the detailed spatial structure of the source. The spot size, the intensity distribution, and the flux level of each source were measured with different operating parameters. During the VETA-I test, microscope pictures were taken for each used anode immediately after it was brought out of the source chamber. The source sizes and the intensity distribution structures are clearly shown in the pictures. They are compared and agree with the results from the pinhole camera measurements. This paper presents the results of the above measurements. The results show that under operating conditions characteristic of the VETA-I test, all the source sizes have a FWHM of less than 0.45 mm. For a source of this size at 528 meters away, the angular size to VETA is less than 0.17 arcsec which is small compared to the on ground VETA angular resolution (0.5 arcsec, required and 0.22 arcsec, measured). Even so, the results show the intensity distributions of the sources have complicated structures. These results were crucial for the VETA data analysis and for obtaining the on ground and predicted in orbit VETA Point Response Function.

  3. Intensity dynamics and statistical properties of random distributed feedback fiber laser.

    PubMed

    Gorbunov, Oleg A; Sugavanam, Srikanth; Churkin, Dmitry V

    2015-04-15

    We present first experimental investigation of fast-intensity dynamics of random distributed feedback (DFB) fiber lasers. We found that the laser dynamics are stochastic on a short time scale and exhibit pronounced fluctuations including generation of extreme events. We also experimentally characterize statistical properties of radiation of random DFB fiber lasers. We found that statistical properties deviate from Gaussian and depend on the pump power.

  4. Intensity and absorbed-power distribution in a cylindrical solar-pumped dye laser

    NASA Technical Reports Server (NTRS)

    Williams, M. D.

    1984-01-01

    The internal intensity and absorbed-power distribution of a simplified hypothetical dye laser of cylindrical geometry is calculated. Total absorbed power is also calculated and compared with laboratory measurements of lasing-threshold energy deposition in a dye cell to determine the suitability of solar radiation as a pump source or, alternatively, what modifications, if any, are necessary to the hypothetical system for solar pumping.

  5. Characterizing the influence of atmospheric river orientation and intensity on precipitation distributions over North Coastal California

    NASA Astrophysics Data System (ADS)

    Hecht, Chad W.; Cordeira, Jason M.

    2017-09-01

    Atmospheric rivers (ARs) are long (>2000 km) and narrow (500-1000 km) corridors of enhanced vertically integrated water vapor and enhanced integrated water vapor transport (IVT) that are responsible for a majority of global poleward moisture transport and can result in extreme orographic precipitation. Observational evidence suggests that ARs within different synoptic-scale flow regimes may contain different water vapor source regions, orientations, and intensities and may result in different precipitation distributions. This study uses k-means clustering to objectively identify different orientations and intensities of ARs that make landfall over the California Russian River watershed. The ARs with different orientations and intensities occur within different synoptic-scale flow patterns in association with variability in IVT direction and quasi-geostrophic forcing for ascent and lead to different precipitation distributions over the Russian River watershed. These differences suggest that both mesoscale upslope moisture flux and synoptic-scale forcing for ascent are important factors in modulating precipitation distributions during landfalling ARs.

  6. The Intensity Distribution for Gamma-Ray Bursts Observed with BATSE

    NASA Technical Reports Server (NTRS)

    Pendleton, Geoffrey N.; Mallozzi, Robert S.; Paciesas, William S.; Briggs, Michael S.; Preece, Robert D.; Koshut, Tom M.; Horack, John M.; Meegan, Charles A.; Fishman, Gerald J.; Hakkila, Jon; Kouveliotou, Cryssa

    1996-01-01

    The intensity distributions of gamma-ray bursts observed by BATSE from 19 April 1991 to 19 September 1994 are presented. For this data set, (V/V(sub max)) is 0.329 +/- 0.011, which is 15.5 sigma away from the value of 0.5 expected for a homogeneous distribution. Standard cosmological model parameters are obtained by fitting the differentially binned peak flux distribution expressed in units of photons cm(exp -2) s(exp -1) in the energy range 50-300 keV. The value of z calculated for a peak flux of 1 photon cm(exp -2) s(exp -1) is 0.8 +/- 0.33. The procedures used to produce the peak flux data and C(sub p)/C(sub lim) data are presented. The differences between the two representations of burst intensity are emphasized so that researchers can determine which type of data is most appropriate for their studies. The sky sensitivity correction as a function of intensity for the peak flux data is also described.

  7. Photoionization branching ratios and vibrational intensity distribution for N2, CO; and CO2 between 53 and 75 nm

    NASA Technical Reports Server (NTRS)

    Samson, J. A. R.; Gardner, J. L.

    1973-01-01

    The probability of radiation producing ions in specific electronic and vibrational levels was documented. For example, when a narrow band-pass of solar ionizing photons is incident on an atmospheric species it is now possible to describe, accurately, how the radiant energy is shared among the various electronic states of the ions produced. The molecules studied were N2, CO, and CO2. These molecules were photoionized by radiation between 53 and 75 nm. The effects of autoionization are discussed and continuum vibrational intensities are tabulated and compared with theoretical Franck-Condon factors where available. The branching ratios and partial cross sections for ionization into various electronic states are tabulated.

  8. Impact of Hydrologic Variability on Nutrient Age Distribution in Intensively Managed Landscapes

    NASA Astrophysics Data System (ADS)

    Kumar, P.; Woo, D. K.

    2014-12-01

    The distribution, concentration, and transport of nutrients in agricultural landscapes are of significant societal concern. Our interests in reactive nitrogen and the nitrogen cycle have shifted from increasing the efficiency of nitrogen delivery to target crop species to decreasing environmental damage caused by intensive agricultural practices. Enhancing the reactive nitrogen use efficiency to increase food production to meet future demand inevitably contributes to an increase in the reactive nitrogen load in the ecosystem, and damaging the environment. However, due to the complexity of the nitrogen cycle, the dynamics of nitrogen in soils and its interactions with ecohydrological processes at the watershed and regional scales are not well understood to enable adequate remedial measures. To unravel the complexity of this dynamics we have developed a model for characterizing the nitrogen age (elapsed time) distribution. The goal of our study is to develop and analyze the dynamics of nitrogen in the context of age and transit times resulting from advection, mixing, and production/destruction processes; evaluate the effects of micro-topographic variability on the nitrogen age distributions; and investigate how the temporal dynamics of the nitrogen age distribution are affected by changes in the variability of climate drivers. Our study is performed for the Upper Sangamon River Basin in the Critical Zone Observatory for Intensively Managed Landscapes (IML-CZO).

  9. Intensity distribution based space and time division multiple access technique for hybrid-LOS indoor optical wireless communication

    NASA Astrophysics Data System (ADS)

    Miyamoto, Shinichi; Kawamoto, Kenji; Sampei, Seiichi

    2010-02-01

    This paper proposes a space division and time division multiple access (SD/TDMA) technique based on intensity distributions for hybrid line-of-sight (hybrid-LOS) indoor optical wireless communication system. At first, a novel signal discrimination scheme for the spatially multiplexed optical signals is proposed and it is applied to a space division multiple access (SDMA) in hybrid-LOS system. In the proposed scheme, multiple terminals simultaneously transmit their optical signals to access point (AP) using on-off-keying (OOK) modulation, and the spatially multiplexed optical signals are received by a photodetectors array (PD-array), where multiple PDs are disposed to observe the spatial intensity distribution of optical signals. Because the terminals transmit their data using OOK modulation, the spatial intensity distribution observed by the AP equipped with PD-array is subject to the data transmitted from individual terminals, and the AP can identify the terminals transmitting the optical signal by determining the transmitted intensity distribution. Of course, the transmitted intensity distributions are not orthogonal signal and the discriminability of transmitted intensity distributions is much related to the differences of intensity distributions. This implies that the number of terminals that can simultaneously access to the AP will be limited and it is determined by the differences of the candidate intensity distributions. In order to enhance the discriminability of the transmitted intensity distributions, the proposed signal discrimination scheme is further applied to the SD/TDMA. In the SD/TDMA, the discriminability required to enable SDMA is ensured by introducing a scheduling algorithm in which terminals with higher discriminatory of transmitted intensity distributions are allocated to the same time slot. Numerical results show that SD/TDMA using proposed signal discrimination scheme increases the throughput and the number of terminals that can access to

  10. Continuum radiation in planetary magnetospheres

    NASA Technical Reports Server (NTRS)

    Kurth, W. S.

    1991-01-01

    With the completion of the Voyager tour of the outer planets, radio and plasma wave instruments have executed the first survey of the wave spectra of Earth, Jupiter, Saturn, Uranus, and Neptune. One of the most notable conclusions of this survey is that there is a great deal of qualitative similarity in both the plasma wave and radio wave spectra from one magnetosphere to the next. In particular, in spite of detailed differences, most of the radio emissions at each of the planets have been tentatively classified into two primary categories. First, the most intense emissions are generally associated with the cyclotron maser instability. Second, a class of weaker emissions can be found at each of the magnetospheres which appears to be the result of conversion from intense electrostatic emissions at the upper hybrid resonance frequency into (primarily) ordinary mode radio emission. It is this second category, often referred to as nonthermal continuum radiation, which we will discuss in this review. We review the characteristics of the continuum spectrum at each of the planets, discuss the source region and direct observations of the generation of the emissions where available, and briefly describe the theories for the generation of the emissions. Over the past few years evidence has increased that the linear mode conversion of electrostatic waves into the ordinary mode can account for at least some of the continuum radiation observed. There is no definitive evidence which precludes the possibility that a nonlinear mechanism may also be important.

  11. Continuum radiation in planetary magnetospheres

    SciTech Connect

    Kurth, W.S.

    1991-12-01

    With the completion of the Voyager tour of the outer planets, radio and plasma wave instruments have executed the first survey of the wave spectra of Earth, Jupiter, Saturn, Uranus, and Neptune. One of the most notable conclusions of this survey is that there is a great deal of qualitative similarity in both the plasma wave and radio wave spectra from one magnetosphere to the next. In particular, in spite of detailed differences, most of the radio emissions at each of the planets have been tentatively classified into two primary categories. First, the most intense emissions are generally associated with the cyclotron maser instability. Second, a class of weaker emissions can be found at each of the magnetospheres which appears to be the result of conversion from intense electrostatic emissions at the upper hybrid resonance frequency into (primarily) ordinary mode radio emission. It is this second category, often referred to as nonthermal continuum radiation, which we will discuss in this review. We review the characteristics of the continuum spectrum at each of the planets, discuss the source region and direct observations of the generation of the emissions where available, and briefly describe the theories for the generation of the emissions. Over the past few years evidence has increased that the linear mode conversion of electrostatic waves into the ordinary mode can account for at least some of the continuum radiation observed. There is no definitive evidence which precludes the possibility that a nonlinear mechanism may also be important.

  12. The Suicide Prevention Continuum

    PubMed Central

    Caldwell, Dawn

    2010-01-01

    The suicide prevention continuum illustrates a practical approach to the complex issue of suicide prevention. The continuum evolved from discussions with two Aboriginal communities in Atlantic Canada about suicide and the different types of interventions available. The continuum offers a framework and reference tool to differentiate between the different stages of suicide risk. It illustrates where the Aboriginal Community Youth Resilience Network (ACYRN) fits into suicide prevention and how it contributes to prevention knowledge, capacity building, and policy development. PMID:20835376

  13. Income Disparities and the Global Distribution of Intensively Farmed Chicken and Pigs

    PubMed Central

    Gilbert, Marius; Conchedda, Giulia; Van Boeckel, Thomas P.; Cinardi, Giuseppina; Linard, Catherine; Nicolas, Gaëlle; Thanapongtharm, Weerapong; D'Aietti, Laura; Wint, William; Newman, Scott H.; Robinson, Timothy P.

    2015-01-01

    The rapid transformation of the livestock sector in recent decades brought concerns on its impact on greenhouse gas emissions, disruptions to nitrogen and phosphorous cycles and on land use change, particularly deforestation for production of feed crops. Animal and human health are increasingly interlinked through emerging infectious diseases, zoonoses, and antimicrobial resistance. In many developing countries, the rapidity of change has also had social impacts with increased risk of marginalisation of smallholder farmers. However, both the impacts and benefits of livestock farming often differ between extensive (backyard farming mostly for home-consumption) and intensive, commercial production systems (larger herd or flock size, higher investments in inputs, a tendency towards market-orientation). A density of 10,000 chickens per km2 has different environmental, epidemiological and societal implications if these birds are raised by 1,000 individual households or in a single industrial unit. Here, we introduce a novel relationship that links the national proportion of extensively raised animals to the gross domestic product (GDP) per capita (in purchasing power parity). This relationship is modelled and used together with the global distribution of rural population to disaggregate existing 10 km resolution global maps of chicken and pig distributions into extensive and intensive systems. Our results highlight countries and regions where extensive and intensive chicken and pig production systems are most important. We discuss the sources of uncertainties, the modelling assumptions and ways in which this approach could be developed to forecast future trajectories of intensification. PMID:26230336

  14. Income Disparities and the Global Distribution of Intensively Farmed Chicken and Pigs.

    PubMed

    Gilbert, Marius; Conchedda, Giulia; Van Boeckel, Thomas P; Cinardi, Giuseppina; Linard, Catherine; Nicolas, Gaëlle; Thanapongtharm, Weerapong; D'Aietti, Laura; Wint, William; Newman, Scott H; Robinson, Timothy P

    2015-01-01

    The rapid transformation of the livestock sector in recent decades brought concerns on its impact on greenhouse gas emissions, disruptions to nitrogen and phosphorous cycles and on land use change, particularly deforestation for production of feed crops. Animal and human health are increasingly interlinked through emerging infectious diseases, zoonoses, and antimicrobial resistance. In many developing countries, the rapidity of change has also had social impacts with increased risk of marginalisation of smallholder farmers. However, both the impacts and benefits of livestock farming often differ between extensive (backyard farming mostly for home-consumption) and intensive, commercial production systems (larger herd or flock size, higher investments in inputs, a tendency towards market-orientation). A density of 10,000 chickens per km2 has different environmental, epidemiological and societal implications if these birds are raised by 1,000 individual households or in a single industrial unit. Here, we introduce a novel relationship that links the national proportion of extensively raised animals to the gross domestic product (GDP) per capita (in purchasing power parity). This relationship is modelled and used together with the global distribution of rural population to disaggregate existing 10 km resolution global maps of chicken and pig distributions into extensive and intensive systems. Our results highlight countries and regions where extensive and intensive chicken and pig production systems are most important. We discuss the sources of uncertainties, the modelling assumptions and ways in which this approach could be developed to forecast future trajectories of intensification.

  15. Experimental verification of a model describing the intensity distribution from a single mode optical fiber

    SciTech Connect

    Moro, Erik A; Puckett, Anthony D; Todd, Michael D

    2011-01-24

    The intensity distribution of a transmission from a single mode optical fiber is often approximated using a Gaussian-shaped curve. While this approximation is useful for some applications such as fiber alignment, it does not accurately describe transmission behavior off the axis of propagation. In this paper, another model is presented, which describes the intensity distribution of the transmission from a single mode optical fiber. A simple experimental setup is used to verify the model's accuracy, and agreement between model and experiment is established both on and off the axis of propagation. Displacement sensor designs based on the extrinsic optical lever architecture are presented. The behavior of the transmission off the axis of propagation dictates the performance of sensor architectures where large lateral offsets (25-1500 {micro}m) exist between transmitting and receiving fibers. The practical implications of modeling accuracy over this lateral offset region are discussed as they relate to the development of high-performance intensity modulated optical displacement sensors. In particular, the sensitivity, linearity, resolution, and displacement range of a sensor are functions of the relative positioning of the sensor's transmitting and receiving fibers. Sensor architectures with high combinations of sensitivity and displacement range are discussed. It is concluded that the utility of the accurate model is in its predicative capability and that this research could lead to an improved methodology for high-performance sensor design.

  16. Variation of rain intensity and drop size distribution with General Weather Patterns (GWL)

    NASA Astrophysics Data System (ADS)

    Ghada, Wael; Buras, Allan; Lüpke, Marvin; Menzel, Annette

    2017-04-01

    Short-duration rainfall extremes may cause flash floods in certain catchments (e.g. cities or fast responding watersheds) and pose a great risk to affected communities. In order to predict their occurrence under future climate change scenarios, their link to atmospheric circulation patterns needs to be well understood. We used a comprehensive data set of meteorological data (temperature, rain gauge precipitation) and precipitation spectra measured by a disdrometer (OTT PARSIVEL) between October 2008 and June 2010 at Freising, southern Germany. For the 21 months of the study period, we integrated the disdrometer spectra over intervals of 10 minutes to correspond to the temporal resolution of the weather station data and discarded measurements with air temperatures below 0°C. Daily General Weather Patterns ("Großwetterlagen", GWL) were downloaded from the website of the German Meteorological Service. Out of the 29 GWL, 14 were included in the analysis for which we had at least 12 rain events during our study period. For the definition of a rain event, we tested different lengths of minimum inter-event times and chose 30 min as a good compromise between number and length of resulting events; rain events started when more than 0.001 mm/h (sensitivity of the disdrometer) were recorded. The length of the rain events ranged between 10 min and 28 h (median 130 min) with the maximum rain intensity recorded being 134 mm/h on 24-07-2009. Seasonal differences were identified for rain event average intensities and maximum intensities per event. The influence of GWL on rain properties such as rain intensity and drop size distribution per time step and per event was investigated based on the above mentioned rain event definition. Pairwise Wilcoxon-tests revealed that higher rain intensity and larger drops were associated with the GWL "Low over the British Isles" (TB), whereas low rain intensities and less drops per interval were associated with the GWL "High over Central Europe

  17. The training intensity distribution among well-trained and elite endurance athletes

    PubMed Central

    Stöggl, Thomas L.; Sperlich, Billy

    2015-01-01

    Researchers have retrospectively analyzed the training intensity distribution (TID) of nationally and internationally competitive athletes in different endurance disciplines to determine the optimal volume and intensity for maximal adaptation. The majority of studies present a “pyramidal” TID with a high proportion of high volume, low intensity training (HVLIT). Some world-class athletes appear to adopt a so-called “polarized” TID (i.e., significant % of HVLIT and high-intensity training) during certain phases of the season. However, emerging prospective randomized controlled studies have demonstrated superior responses of variables related to endurance when applying a polarized TID in well-trained and recreational individuals when compared with a TID that emphasizes HVLIT or threshold training. The aims of the present review are to: (1) summarize the main responses of retrospective and prospective studies exploring TID; (2) provide a systematic overview on TIDs during preparation, pre-competition, and competition phases in different endurance disciplines and performance levels; (3) address whether one TID has demonstrated greater efficacy than another; and (4) highlight research gaps in an effort to direct future scientific studies. PMID:26578968

  18. Impacts of Fog Characteristics, Forward Illumination, and Warning Beacon Intensity Distribution on Roadway Hazard Visibility

    PubMed Central

    2016-01-01

    Warning beacons are critical for the safety of transportation, construction, and utility workers. These devices need to produce sufficient luminous intensity to be visible without creating glare to drivers. Published standards for the photometric performance of warning beacons do not address their performance in conditions of reduced visibility such as fog. Under such conditions light emitted in directions other than toward approaching drivers can create scattered light that makes workers and other hazards less visible. Simulations of visibility of hazards under varying conditions of fog density, forward vehicle lighting, warning beacon luminous intensity, and intensity distribution were performed to assess their impacts on visual performance by drivers. Each of these factors can influence the ability of drivers to detect and identify workers and hazards along the roadway in work zones. Based on the results, it would be reasonable to specify maximum limits on the luminous intensity of warning beacons in directions that are unlikely to be seen by drivers along the roadway, limits which are not included in published performance specifications. PMID:27314058

  19. The training intensity distribution among well-trained and elite endurance athletes.

    PubMed

    Stöggl, Thomas L; Sperlich, Billy

    2015-01-01

    Researchers have retrospectively analyzed the training intensity distribution (TID) of nationally and internationally competitive athletes in different endurance disciplines to determine the optimal volume and intensity for maximal adaptation. The majority of studies present a "pyramidal" TID with a high proportion of high volume, low intensity training (HVLIT). Some world-class athletes appear to adopt a so-called "polarized" TID (i.e., significant % of HVLIT and high-intensity training) during certain phases of the season. However, emerging prospective randomized controlled studies have demonstrated superior responses of variables related to endurance when applying a polarized TID in well-trained and recreational individuals when compared with a TID that emphasizes HVLIT or threshold training. The aims of the present review are to: (1) summarize the main responses of retrospective and prospective studies exploring TID; (2) provide a systematic overview on TIDs during preparation, pre-competition, and competition phases in different endurance disciplines and performance levels; (3) address whether one TID has demonstrated greater efficacy than another; and (4) highlight research gaps in an effort to direct future scientific studies.

  20. The enhanced measurement-device-independent quantum key distribution with two-intensity decoy states

    NASA Astrophysics Data System (ADS)

    Zhu, Jian-Rong; Zhu, Feng; Zhou, Xing-Yu; Wang, Qin

    2016-09-01

    We put forward a new scheme for implementing the measurement-device-independent quantum key distribution (QKD) with weak coherent source, while using only two different intensities. In the new scheme, we insert a beam splitter and a local detector at both Alice's and Bob's side, and then all the triggering and non-triggering signals could be employed to process parameter estimations, resulting in very precise estimations for the two-single-photon contributions. Besides, we compare its behavior with two other often used methods, i.e., the conventional standard three-intensity decoy-state measurement-device-independent QKD and the passive measurement-device-independent QKD. Through numerical simulations, we demonstrate that our new approach can exhibit outstanding characteristics not only in the secure transmission distance, but also in the final key generation rate.

  1. HOT ELECTRON ENERGY DISTRIBUTIONS FROM ULTRA-INTENSE LASER SOLID INTERACTIONS

    SciTech Connect

    Chen, H; Wilks, S C; Kruer, W; Patel, P; Shepherd, R

    2008-10-08

    Measurements of electron energy distributions from ultra-intense (>10{sup 19} W/cm{sup 2}) laser-solid interactions using an electron spectrometer are presented. These measurements were performed on the Vulcan petawatt laser at Rutherford Appleton Laboratory and the Callisto laser at Lawrence Livermore National Laboratory. The effective hot electron temperatures (T{sub hot}) have been measured for laser intensities (I{lambda}{sup 2}) from 10{sup 18} W/cm{sup 2} {micro}m{sup 2} to 10{sup 21} W/cm{sup 2} {micro}m{sup 2} for the first time, and T{sub hot} is found to increase as (I{lambda}{sup 2}){sup 0.34} {+-} 0.4. This scaling agrees well with the empirical scaling published by Beg et al. (1997), and is explained by a simple physical model that gives good agreement with experimental results and particle-in-cell simulations.

  2. Continuous-variable quantum key distribution with random intensity fluctuation of the local oscillator

    NASA Astrophysics Data System (ADS)

    Gui, Ming; Huang, Ming-Qiu; Liang, Lin-Mei

    2016-10-01

    In practical continuous-variable quantum key distribution (CVQKD) systems, due to environmental disturbance or some intrinsic imperfections of devices, inevitably the local oscillator (LO) employed in a coherent detection always fluctuates arbitrarily over time, which compromises the security and performance of practical CVQKD systems. In this paper, we investigate the performance of practical CVQKD systems with LO fluctuating randomly. By revising the measurement result of balanced homodyne detection and embedding fluctuation parameters into security analysis, we find that in addition to the average LO intensity, the fluctuation variance also severely affects the secret key rate. No secret key can be obtained if fluctuation variance is relatively large. This indicates that in a practical CVQKD, LO intensity should be well monitored and stabilized. Our research can be directly applied to improve the robustness of a practical CVQKD system as well as be used to optimize CVQKD protocols.

  3. Spatially intensive sampling by electrofishing for assessing longitudinal discontinuities in fish distribution in a headwater stream

    USGS Publications Warehouse

    Le Pichon, Céline; Tales, Évelyne; Belliard, Jérôme; Torgersen, Christian E.

    2017-01-01

    Spatially intensive sampling by electrofishing is proposed as a method for quantifying spatial variation in fish assemblages at multiple scales along extensive stream sections in headwater catchments. We used this method to sample fish species at 10-m2 points spaced every 20 m throughout 5 km of a headwater stream in France. The spatially intensive sampling design provided information at a spatial resolution and extent that enabled exploration of spatial heterogeneity in fish assemblage structure and aquatic habitat at multiple scales with empirical variograms and wavelet analysis. These analyses were effective for detecting scales of periodicity, trends, and discontinuities in the distribution of species in relation to tributary junctions and obstacles to fish movement. This approach to sampling riverine fishes may be useful in fisheries research and management for evaluating stream fish responses to natural and altered habitats and for identifying sites for potential restoration.

  4. Intensity and polarization of light scattered by size distributions of randomly oriented nonspherical particles

    NASA Technical Reports Server (NTRS)

    Mishchenko, M. I.; Travis, L. D.

    1993-01-01

    Calculations of light scattering by small particles are important in many diverse fields of science and engineering. In many cases of practical interest, scattering particles are nonspherical and are distributed over sizes and orientations. However, accurate light scattering computations for ensembles of nonspherical particles are difficult and time-consuming, and the literature in which such calculations are reported is rather scarce. In this paper, the T-matrix approach, as extended recently to randomly oriented particles, is used to calculate rigorously light scattering by size distributions of randomly oriented axially symmetric particles. To model the variation of particle sizes in real ensembles, we use a power law distribution typical of some terrestrial aerosols. Contour plots of intensity and degree of linear polarization for polydisperse prolate and oblate spheroids of different aspect ratios and effective equivalent-sphere size parameters from 0 to 10 are calculated and compared with calculations for equivalent spheres. The angular scattering behavior of nonspherical polydispersions is found to be greatly different from that of spheres, while the scattering properties of oblate and prolate spheroids of the same aspect ratio are similar. With increasing particle size, both intensity and polarization become more shape-dependent. In general, nonspherical particles are stronger side scatterers and weaker backscatterers than equivalent spheres. With increasing aspect ratio of nonspherical particles polarization tends to be predominantly positive. Possible effects of particle nonsphericity on optical remote sensing of atmospheric aerosols are discussed.

  5. The Interannual Stability of Cumulative Frequency Distributions for Convective System Size and Intensity

    NASA Technical Reports Server (NTRS)

    Mohr, Karen I.; Molinari, John; Thorncroft, Chris D,

    2010-01-01

    The characteristics of convective system populations in West Africa and the western Pacific tropical cyclone basin were analyzed to investigate whether interannual variability in convective activity in tropical continental and oceanic environments is driven by variations in the number of events during the wet season or by favoring large and/or intense convective systems. Convective systems were defined from TRMM data as a cluster of pixels with an 85 GHz polarization-corrected brightness temperature below 255 K and with an area at least 64 km 2. The study database consisted of convective systems in West Africa from May Sep for 1998-2007 and in the western Pacific from May Nov 1998-2007. Annual cumulative frequency distributions for system minimum brightness temperature and system area were constructed for both regions. For both regions, there were no statistically significant differences among the annual curves for system minimum brightness temperature. There were two groups of system area curves, split by the TRMM altitude boost in 2001. Within each set, there was no statistically significant interannual variability. Sub-setting the database revealed some sensitivity in distribution shape to the size of the sampling area, length of sample period, and climate zone. From a regional perspective, the stability of the cumulative frequency distributions implied that the probability that a convective system would attain a particular size or intensity does not change interannually. Variability in the number of convective events appeared to be more important in determining whether a year is wetter or drier than normal.

  6. Effect of air-sea coupling on the frequency distribution of intense tropical cyclones over the northwestern Pacific

    NASA Astrophysics Data System (ADS)

    Ogata, Tomomichi; Mizuta, Ryo; Adachi, Yukimasa; Murakami, Hiroyuki; Ose, Tomoaki

    2015-12-01

    Effect of air-sea coupling on the frequency distribution of intense tropical cyclones (TCs) over the northwestern Pacific (NWP) region is investigated using an atmosphere and ocean coupled general circulation model (AOGCM). Monthly varying flux adjustment enables AOGCM to simulate both subseasonal air-sea interaction and realistic seasonal to interannual sea surface temperature (SST) variability. The maximum of intense TC distribution around 20-30°N in the AGCM shifts equatorward in the AOGCM due to the air-sea coupling. Hence, AOGCM reduces northward intense TC distribution bias seen in AGCM. Over the NWP, AOGCM-simulated SST variability is large around 20-30°N where the warm mixed layer becomes shallower rapidly. Active entrainment from subsurface water over this region causes stronger SST cooling, and hence, TC intensity decreases. These results suggest that air-sea coupling characterized by subsurface oceanic condition causes more realistic distribution of intense TCs over the NWP.

  7. A Method of Estimating Pressure and Intensity Distributions of Multielement Phased Array High Intensity Focused Ultrasonic Field at Full Power Using a Needle Hydrophone

    NASA Astrophysics Data System (ADS)

    Ying, Yu; Guofeng, Shen; Jingfeng, Bai; Yazhu, Chen

    2011-09-01

    The pressure and intensity distribution of high intensity focused ultrasound (HIFU) fields at full power are critical for predicting heating patterns and ensuring safety of the therapy. With the limitations of maximum pressure at the hydrophone and damage from cavitation or thermal effects, it is hard to measure pressure and intensity directly when HIFU is at full power. HIFU-phased arrays are usually composed of large numbers of small elements and the sound power radiated from some of them at full power is measureable using a hydrophone, we grouped them based on the limitation of maximum permissible pressure at the hydrophone and the characteristics of the element arrangement in the array. Then sound field measurement of the group was carried out at full power level. Using the acoustic coherence principle, the pressure and intensity distribution of the array at full power level can be calculated from corresponding values from the groups. With this method, computer simulations and sound field measurement of a 65-element concentric distributed phased array was carried out. The simulation results demonstrate theoretically the feasibility of this method. Measurements on the 65-element phased array also verify the effectiveness of this method for estimating the pressure and intensity distribution of phased array at full power level using a needle hydrophone.

  8. Target micro-displacement measurement by a "comb" structure of intensity distribution in laser plasma propulsion

    NASA Astrophysics Data System (ADS)

    Zheng, Z. Y.; Zhang, S. Q.; Gao, L.; Gao, H.

    2015-05-01

    A "comb" structure of beam intensity distribution is designed and achieved to measure a target displacement of micrometer level in laser plasma propulsion. Base on the "comb" structure, the target displacement generated by nanosecond laser ablation solid target is measured and discussed. It is found that the "comb" structure is more suitable for a thin film target with a velocity lower than tens of millimeters per second. Combing with a light-electric monitor, the `comb' structure can be used to measure a large range velocity.

  9. A combination of JND curve property and intensity-pair distribution for image enhancement

    NASA Astrophysics Data System (ADS)

    Zou, Bin; Lu, Yang; Qian, Jun; He, Junfeng; Li, Liangfu; Zhou, Guoliang; Yang, Yizhou; Yan, Haozheng

    2017-02-01

    In recent years, the distribution characteristic of pixel intensity-pairs is proposed, which effectively absorbing the advantages of global and local image enhancement algorithms, avoiding over enhancement, noise amplification and other defects. However, the performance of the algorithm is heavily dependent on the selection of local artificial thresholds. In this paper, by the Just Noticeable Difference(JND) curve from human visual system, dynamic thresholds with visual sense are generated. Then image pixels are divided into different channels for statistical processing, in order to construct mapping functions. Finally, the enhanced image is a weighted fusion of different channels. The experiment results show that the proposed algorithm has better effect and adaptability.

  10. Continuous-variable quantum key distribution under the local oscillator intensity attack with noiseless linear amplifier

    NASA Astrophysics Data System (ADS)

    Yang, Fangli; Shi, Ronghua; Guo, Ying; Shi, JinJing; Zeng, Guihua

    2015-08-01

    An improved continuous-variable quantum key distribution (CVQKD) protocol is proposed to improve the performance of CVQKD system under the local oscillator intensity attack by using a suitable noiseless linear amplifier (NLA) at the destination. This method can enhance the efficiency of the CVQKD scheme in terms of the maximum transmission distance, no matter whether the direct or reverse reconciliation is used. Simulation results show that there is a considerable increase in the transmission distance for the NLA-based CVQKD by adjusting the values of the parameters.

  11. Energy partitioning and electron momentum distributions in intense laser-solid interactions

    NASA Astrophysics Data System (ADS)

    Magnusson, Joel; Gonoskov, Arkady; Marklund, Mattias

    2017-09-01

    Producing inward orientated streams of energetic electrons by intense laser pulses acting on solid targets is the most robust and accessible way of transferring the laser energy to particles, which underlies numerous applications, ranging from TNSA to laboratory astrophysics. Structures with the scale of the laser wavelength can significantly enhance energy absorption, which has been in the center of attention in recent studies. In this article, we demonstrate and assess the effect of the structures for widening the angular distribution of generated energetic electrons. We analyse the results of PIC simulations and reveal several aspects that can be important for the related applications.

  12. Numerical ray-tracing approach with laser intensity distribution for LIDAR signal power function computation

    NASA Astrophysics Data System (ADS)

    Shi, Guangyuan; Li, Song; Huang, Ke; Li, Zile; Zheng, Guoxing

    2016-10-01

    We have developed a new numerical ray-tracing approach for LIDAR signal power function computation, in which the light round-trip propagation is analyzed by geometrical optics and a simple experiment is employed to acquire the laser intensity distribution. It is relatively more accurate and flexible than previous methods. We emphatically discuss the relationship between the inclined angle and the dynamic range of detector output signal in biaxial LIDAR system. Results indicate that an appropriate negative angle can compress the signal dynamic range. This technique has been successfully proved by comparison with real measurements.

  13. Oral Language Continuum.

    ERIC Educational Resources Information Center

    Fresno County Dept. of Education, Fresno, CA.

    An oral language continuum designed to help elementary students develop techniques for a variety of speech situations, learn to listen, and learn to be aware of the responsibility of the speaker is presented. The continuum is divided into four sections. Student needs, implications for teaching, and suggested activities are arranged sequentially.…

  14. Atomic ionization by intense laser pulses of short duration: Photoelectron energy and angular distributions

    SciTech Connect

    Dondera, M.

    2010-11-15

    We introduce an adequate integral representation of the wave function in the asymptotic region, valid for the stage postinteraction between a one-electron atom and a laser pulse of short duration, as a superposition of divergent radial spherical waves. Starting with this representation, we derive analytic expressions for the energy and angular distributions of the photoelectrons and we show their connection with expressions used before in the literature. Using our results, we propose a method to extract the photoelectron distributions from the time dependence of the wave function at large distances. Numerical results illustrating the method are presented for the photoionization of hydrogenlike atoms from the ground state and several excited states by extreme ultraviolet pulses with a central wavelength of 13.3 nm and several intensities around the value I{sub 0}{approx_equal}3.51x10{sup 16} W/cm{sup 2}.

  15. Predicting photoemission intensities and angular distributions with real-time density-functional theory

    NASA Astrophysics Data System (ADS)

    Dauth, M.; Kümmel, S.

    2016-02-01

    Photoemission spectroscopy is one of the most frequently used tools for characterizing the electronic structure of condensed matter systems. We discuss a scheme for simulating photoemission from finite systems based on time-dependent density-functional theory. It allows for the first-principles calculation of relative electron binding energies, ionization cross sections, and anisotropy parameters. We extract these photoemission spectroscopy observables from Kohn-Sham orbitals propagated in real time. We demonstrate that the approach is capable of estimating photoemission intensities, i.e., peak heights. It can also reliably predict the angular distribution of photoelectrons. For the example of benzene we contrast calculated angular distribution anisotropy parameters to experimental reference data. Self-interaction free Kohn-Sham theory yields meaningful outer valence single-particle states in the right energetic order. We discuss how to properly choose the complex absorbing potential that is used in the simulations.

  16. Prediction of thermal coagulation from the instantaneous strain distribution induced by high-intensity focused ultrasound

    NASA Astrophysics Data System (ADS)

    Iwasaki, Ryosuke; Takagi, Ryo; Tomiyasu, Kentaro; Yoshizawa, Shin; Umemura, Shin-ichiro

    2017-07-01

    The targeting of the ultrasound beam and the prediction of thermal lesion formation in advance are the requirements for monitoring high-intensity focused ultrasound (HIFU) treatment with safety and reproducibility. To visualize the HIFU focal zone, we utilized an acoustic radiation force impulse (ARFI) imaging-based method. After inducing displacements inside tissues with pulsed HIFU called the push pulse exposure, the distribution of axial displacements started expanding and moving. To acquire RF data immediately after and during the HIFU push pulse exposure to improve prediction accuracy, we attempted methods using extrapolation estimation and applying HIFU noise elimination. The distributions going back in the time domain from the end of push pulse exposure are in good agreement with tissue coagulation at the center. The results suggest that the proposed focal zone visualization employing pulsed HIFU entailing the high-speed ARFI imaging method is useful for the prediction of thermal coagulation in advance.

  17. 9-year distributions of rain intensities measured in Prague and their utilization in telecommunications

    NASA Astrophysics Data System (ADS)

    Kvicera, V.; Grabner, M.

    2012-04-01

    Experimental research in the Department of Frequency Engineering of the Czech Metrology Institute (CMI) in Prague, the Czech Republic, is focused on stability of received signals on terrestrial radio and optical communication paths. Hydrometeors (rain, snow, fog, hails) can cause serious attenuation of electromagnetic waves in the frequency bands above 10 GHz and the availability performances of terrestrial radio communication systems are seriously affected by heavy hydrometeors events. The rain intensity data is usually used for the calculations of attenuation due to rain on terrestrial radio links in accordance with either the relevant ITU-R Recommendation or other methods. Therefore, our experimental research is also focused on our own meteorological measurements in the vicinity of experimental radio and optical paths. The heated tipping-bucket rain gauge with the collector area of 500 cm2 and the rain amount per tip of 0.1 mm is used at CMI for the measurements of intensities of hydrometeors. The time of tips is recorded with uncertainty of 1 second. Hydrometeors intensity data obtained from January 2003 to December 2011 (9 years of observation) was statistically processed over the individual years. All the recorded individual hydrometeor events were compared with the concurrent meteorological conditions and were carefully categorized according to the types of individual hydrometeors, i.e. rain, rain with snow, rain with hails, snow, fog, fog with rain, fog with snow, and fog with rain and snow. The obtained cumulative distributions (CDs) of intensities of individual hydrometeors over 9 years of observation will be presented and compared with the CD of intensities of all hydrometeors together. The rain amounts were examined too. The obtained rain amounts for individual years and the average rain amounts for individual months over the 9-year period will be given. The obtained CD of average 1-minute rain intensities for the average year over the 9-year period of

  18. Periodic amplitude variations in Jovian continuum radiation

    NASA Technical Reports Server (NTRS)

    Kurth, W. S.; Gurnett, D. A.; Scarf, F. L.

    1986-01-01

    An analysis of periodic variations in the amplitude of continuum radiation near 3 kHz trapped in the Jovian magnetosphere shows structure with periods near both five and ten hours. Contrary to a plausible initial idea, the continuum amplitudes are not organized by position of the observer relative to the dense plasma sheet. Instead, there seem to be preferred orientations of system III longitude with respect to the direction to the sun which account for the peaks. This implies a clock-like modulation of the continuum radiation intensity as opposed to a searchlight effect. The importance of the dipole longitude-solar wind alignment to the amplitude of the continuum radiation implies the source region of the radiation is near the magnetopause and may indirectly tie the generation of the radio waves to the clocklike modulation of energetic electron fluxes from Jupiter.

  19. The Intensity Distribution of Faint Gamma-Ray Bursts Detected with BATSE

    NASA Technical Reports Server (NTRS)

    Kommers, Jefferson; Lewin, Walter H.; Kouveliotou, Chryssa; vanParadijs, Jan; Pendleton, Geoffrey N.; Meegan, Charles A.; Fishman, Gerald J.

    1998-01-01

    We have recently completed a search of 6 years of archival Burst and Transient Source Experiment (BATSE) data for gamma-ray bursts (GRBS) that were too faint to activate the real-time burst detection system running onboard the spacecraft. These "non-triggered" bursts can be combined with the "triggered" bursts detected onboard to produce a GRB intensity distribution that reaches peak fluxes a factor of approximately 2 lower than could be studied previously. The value of the (V/V(max)) statistic (in Euclidean space) for the bursts we detect is 0.177 +/- 0.006. This surprisingly low value is obtained because we detected very few bursts on the 4.096 s and 8.192 s time scales (where most bursts have their highest signal-to-noise ratio) that were not already detected on the 1.024 s time scale. If allowance is made for a power-law distribution of intrinsic peak luminosities, the extended peak flux distribution is consistent with models in which the redshift distribution of the gamma-ray burst rate approximately traces the star formation history of the Universe. We argue that this class of models is preferred over those in which the burst rate is independent of redshift. These results lend support to the conclusions of previous studies predicting that relatively few faint bursts are waiting to be found below the BATSE onboard detection threshold.

  20. A unified description of spatial and spectral distribution of fluctuation intensities in wall turbulence

    NASA Astrophysics Data System (ADS)

    Ji, Yong; She, Zhen-Su

    2016-11-01

    The streamwise turbulent intensity in wall turbulence (pipe and boundary layer) presents non-uniform distribution in both physical and wave number space. The well-known Townsend-Perry attached eddy hypothesis divides the energy spectrum into three distinct ranges: a constant range at small wavenumbers kdistribution of fluctuation intensity from a recently developed symmetry approach.

  1. Experimental observation of spatially resolved photo-luminescence intensity distribution in dual mode upconverting nanorod bundles

    NASA Astrophysics Data System (ADS)

    Kumar, Pawan; Singh, Satbir; Singh, V. N.; Singh, Nidhi; Gupta, R. K.; Gupta, Bipin Kumar

    2017-02-01

    A novel method for demonstration of photoluminescence intensity distribution in upconverting nanorod bundles using confocal microscopy is reported. Herein, a strategy for the synthesis of highly luminescent dual mode upconverting/downshift Y1.94O3:Ho3+0.02/Yb3+0.04 nanorod bundles by a facile hydrothermal route has been introduced. These luminescent nanorod bundles exhibit strong green emission at 549 nm upon excitations at 449 nm and 980 nm with quantum efficiencies of ~6.3% and ~1.1%, respectively. The TEM/HRTEM results confirm that these bundles are composed of several individual nanorods with diameter of ~100 nm and length in the range of 1–3 μm. Furthermore, two dimensional spatially resolved photoluminescence intensity distribution study has been carried out using confocal photoluminescence microscope throughout the nanorod bundles. This study provides a new direction for the potential use of such emerging dual mode nanorod bundles as photon sources for next generation flat panel optical display devices, bio-medical applications, luminescent security ink and enhanced energy harvesting in photovoltaic applications.

  2. Experimental observation of spatially resolved photo-luminescence intensity distribution in dual mode upconverting nanorod bundles

    PubMed Central

    Kumar, Pawan; Singh, Satbir; Singh, V. N.; Singh, Nidhi; Gupta, R. K.; Gupta, Bipin Kumar

    2017-01-01

    A novel method for demonstration of photoluminescence intensity distribution in upconverting nanorod bundles using confocal microscopy is reported. Herein, a strategy for the synthesis of highly luminescent dual mode upconverting/downshift Y1.94O3:Ho3+0.02/Yb3+0.04 nanorod bundles by a facile hydrothermal route has been introduced. These luminescent nanorod bundles exhibit strong green emission at 549 nm upon excitations at 449 nm and 980 nm with quantum efficiencies of ~6.3% and ~1.1%, respectively. The TEM/HRTEM results confirm that these bundles are composed of several individual nanorods with diameter of ~100 nm and length in the range of 1–3 μm. Furthermore, two dimensional spatially resolved photoluminescence intensity distribution study has been carried out using confocal photoluminescence microscope throughout the nanorod bundles. This study provides a new direction for the potential use of such emerging dual mode nanorod bundles as photon sources for next generation flat panel optical display devices, bio-medical applications, luminescent security ink and enhanced energy harvesting in photovoltaic applications. PMID:28211891

  3. Vertical distribution of precipitation particles in Baiu frontal stratiform intense rainfall around Okinawa Island, Japan

    NASA Astrophysics Data System (ADS)

    Oue, M.; Ohigashi, T.; Tsuboki, K.; Nakakita, E.

    2015-06-01

    The vertical distribution of precipitation particles in an intensely precipitating stratiform cloud associated with the Baiu front around Okinawa Island was observed. X-band polarimetric radar, disdrometer, and hydrometeor videosonde data were used to examine the precipitation processes. The cloud top was approximately 12 km above sea level, as convection was depressed while stratiform regions developed near Okinawa Island. In the rain region below 3 km, the mean median volume diameter of the raindrop size distribution (DSD) estimated from the radar variables was 1.55 mm, and the mean normalized intercept parameter was 104.12 mm-1 m-3 with a mean radar reflectivity of 40.5 dBZe. The DSD indicates that the stratiform precipitation was characterized by higher number concentrations of smaller drops than observed previously in convective cells in a Baiu frontal convective precipitation region around Okinawa Island. The DSD also suggests the presence of larger raindrops than in convective cells embedded in a Baiu frontal stratiform precipitation region around Okinawa Island. In the ice region at 5-6 km, just above the melting layer and 6 km below the cloud top, the differential reflectivity and specific differential phase showed positive values, and videosonde measurements revealed that the number concentration of column-, plate-, and capped-column-like crystals (maximum dimensions of ≥0.1 mm) was 112 L-1. The high number concentration of these crystals contributed to the intense stratiform rainfall associated with the Baiu front.

  4. Planetary distribution of the intensity of Auroral luminosity obtained using a model of Aurora precipitation

    NASA Astrophysics Data System (ADS)

    Vorobjev, V. G.; Kirillov, A. S.; Katkalov, Ju. V.; Yagodkina, O. I.

    2013-11-01

    A model of auroral precipitation (AP) developed on the basis of statistical processing of DMSP F6 and F7 satellite data (Vorobjev and Yagodkina, 2005, 2007) was used for the calculation of the global distribution of the auroral luminosity in different spectral ranges. The algorithm for the calculation of the integral intensity in bands N2 LBH (170.0 nm), ING N{2/+} (391.4 nm), 1PG N2 (669.0 nm), and (OI) 557.7-nm emission is shown in detail. The processes of formation of electronically excited atoms O(1S) as a result of the transport of excitation energy from metastable state N2(A3Σ{u/+}), excitation of O(3P) by primary and secondary electrons, and dissociative recombination were taken into account to calculate the intensity of emission at 557.7 nm. A high correlation between the model distribution of the auroral luminosity in the UV spectral range and the observations of the Polar satellite is demonstrated.

  5. Derivation from first principles of the statistical distribution of the mass peak intensities of MS data.

    PubMed

    Ipsen, Andreas

    2015-02-03

    Despite the widespread use of mass spectrometry (MS) in a broad range of disciplines, the nature of MS data remains very poorly understood, and this places important constraints on the quality of MS data analysis as well as on the effectiveness of MS instrument design. In the following, a procedure for calculating the statistical distribution of the mass peak intensity for MS instruments that use analog-to-digital converters (ADCs) and electron multipliers is presented. It is demonstrated that the physical processes underlying the data-generation process, from the generation of the ions to the signal induced at the detector, and on to the digitization of the resulting voltage pulse, result in data that can be well-approximated by a Gaussian distribution whose mean and variance are determined by physically meaningful instrumental parameters. This allows for a very precise understanding of the signal-to-noise ratio of mass peak intensities and suggests novel ways of improving it. Moreover, it is a prerequisite for being able to address virtually all data analytical problems in downstream analyses in a statistically rigorous manner. The model is validated with experimental data.

  6. The role of precipitation type, intensity, and spatial distribution in source water quality after wildfire

    NASA Astrophysics Data System (ADS)

    Murphy, Sheila F.; Writer, Jeffrey H.; Blaine McCleskey, R.; Martin, Deborah A.

    2015-08-01

    Storms following wildfires are known to impair drinking water supplies in the southwestern United States, yet our understanding of the role of precipitation in post-wildfire water quality is far from complete. We quantitatively assessed water-quality impacts of different hydrologic events in the Colorado Front Range and found that for a three-year period, substantial hydrologic and geochemical responses downstream of a burned area were primarily driven by convective storms with a 30 min rainfall intensity >10 mm h-1. These storms, which typically occur several times each year in July-September, are often small in area, short-lived, and highly variable in intensity and geographic distribution. Thus, a rain gage network with high temporal resolution and spatial density, together with high-resolution stream sampling, are required to adequately characterize post-wildfire responses. We measured total suspended sediment, dissolved organic carbon (DOC), nitrate, and manganese concentrations that were 10-156 times higher downstream of a burned area compared to upstream during relatively common (50% annual exceedance probability) rainstorms, and water quality was sufficiently impaired to pose water-treatment concerns. Short-term water-quality impairment was driven primarily by increased surface runoff during higher intensity convective storms that caused erosion in the burned area and transport of sediment and chemical constituents to streams. Annual sediment yields downstream of the burned area were controlled by storm events and subsequent remobilization, whereas DOC yields were closely linked to annual runoff and thus were more dependent on interannual variation in spring runoff. Nitrate yields were highest in the third year post-wildfire. Results from this study quantitatively demonstrate that water quality can be altered for several years after wildfire. Because the southwestern US is prone to wildfires and high-intensity rain storms, the role of storms in post

  7. La Nina and Indian Ocean Dipole Influence on Distribution of Daily Rain Intensities in India

    NASA Astrophysics Data System (ADS)

    Krishnaswamy, J.; Srinivas, V.

    2015-12-01

    The Indian monsoon (IM) and daily extreme rainfall events (EREs) have a major influence on the welfare of 1.2 billion people in South Asia. ERE s have killed tens of thousands of people and severely affected millions of people in the past decade alone in India. Current evidence suggests that the dynamics of the IM, as well as the corresponding frequency and magnitude of daily EREs are changing (Krishnaswamy et al 45(1-2), 175-184, Climate Dynamics 2014).Variability in the Indian monsoon (IM)and associated rain intensitiesis known to be modulated by two ocean atmosphere phenomena, El Nino-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). This is compounded by changes in the hydrological cycle due to global warming. There is growing evidence that the proportion of moderate rains have declined and those of sparse and more intense rains have increased. We investigated the role of La Nina and IOD on the time-aggregated as well as time-evolving distribution of daily rain intensities India using data from rain gauges and gridded rain data. We applied dynamic linear models, generalized linear and additive to compare the relative influence of La Nina and IOD on frequency of different daily rain exceedance levels (25, 50,100,150 and 200 mm day-1) as well as trends since 1950. Our results indicate that La Nina has a very significant influence on annual frequency of moderate rain intensities (<100 mm day-1), whereas IOD has a greater influence on annual proportion of total rain accounted for by rain intensities above 100 and 150 mm day-1. The observed declining role of La Nina in India in recent decades, potentially more moisture availability under climate change, and the strengthening of the IOD due to warming of the Western Indian Ocean could strengthen the shift towards more extreme rain events in the coming decades.

  8. The role of precipitation type, intensity, and spatial distribution in source water quality after wildfire

    USGS Publications Warehouse

    Murphy, Sheila F.; Writer, Jeffrey H.; McCleskey, R. Blaine; Martin, Deborah A.

    2015-01-01

    Storms following wildfires are known to impair drinking water supplies in the southwestern United States, yet our understanding of the role of precipitation in post-wildfire water quality is far from complete. We quantitatively assessed water-quality impacts of different hydrologic events in the Colorado Front Range and found that for a three-year period, substantial hydrologic and geochemical responses downstream of a burned area were primarily driven by convective storms with a 30 min rainfall intensity >10 mm h−1. These storms, which typically occur several times each year in July–September, are often small in area, short-lived, and highly variable in intensity and geographic distribution. Thus, a rain gage network with high temporal resolution and spatial density, together with high-resolution stream sampling, are required to adequately characterize post-wildfire responses. We measured total suspended sediment, dissolved organic carbon (DOC), nitrate, and manganese concentrations that were 10–156 times higher downstream of a burned area compared to upstream during relatively common (50% annual exceedance probability) rainstorms, and water quality was sufficiently impaired to pose water-treatment concerns. Short-term water-quality impairment was driven primarily by increased surface runoff during higher intensity convective storms that caused erosion in the burned area and transport of sediment and chemical constituents to streams. Annual sediment yields downstream of the burned area were controlled by storm events and subsequent remobilization, whereas DOC yields were closely linked to annual runoff and thus were more dependent on interannual variation in spring runoff. Nitrate yields were highest in the third year post-wildfire. Results from this study quantitatively demonstrate that water quality can be altered for several years after wildfire. Because the southwestern US is prone to wildfires and high-intensity rain storms, the role of storms in post

  9. Far field intensity distributions due to spatial self phase modulation of a Gaussian beam by a thin nonlocal nonlinear media.

    PubMed

    Ramirez, E V Garcia; Carrasco, M L Arroyo; Otero, M M Mendez; Cerda, S Chavez; Castillo, M D Iturbe

    2010-10-11

    In this work we present a simple model that can be used to calculate the far field intensity distributions when a Gaussian beam cross a thin sample of nonlinear media but the response can be nonlocal.

  10. Intensity distribution and impact of scatter for dual-source CT

    NASA Astrophysics Data System (ADS)

    Kyriakou, Yiannis; Kalender, Willi A.

    2007-12-01

    Apart from forward scatter, which is given for all CT scanners, dual-source CT (DSCT) is also affected by cross-scatter photons from the second tube-detector system arranged at 90°. We investigated the magnitude and distribution of scatter for DSCT and its impact on image quality. Simulations and measurements of homogeneous and anthropomorphic phantoms were conducted for a DSCT scanner (SOMATOM Definition, Siemens Medical Solutions, Forchheim, Germany) at tube voltages of 80 and 120 kV. The simulations of forward scatter were carried out using combined analytical and Monte Carlo simulation methods for a collimation of 19.2 mm for both tube-detector systems. Measurements of cross scatter were performed by switching one tube off, still reading out the corresponding detector. The relative scatter fractions and the distribution of cross scatter were registered for various imaging conditions. Additionally, a detailed noise analysis with respect to the correction of cross-scatter artifacts is provided to evaluate the performance of correction algorithms. The forward-scatter fraction increased with increasing phantom diameter from 0.02 up to 0.11 for PMMA phantoms of 80 to 400 mm diameter. For cross scatter, the mean intensity was equivalent to forward scatter for small phantoms but was larger for increased phantom size and resulted in severe artifacts in the reconstructed images. The outer dimensions and shape of the object are decisive for the cross-scatter intensity distribution whereas the influence of the degree of inhomogeneity of the respective phantom appears to be negligible. Scatter correction suppressed cross-scatter artifacts but increased noise as a function of the cross-scatter fraction. The magnitude of scatter is not negligible for DSCT systems and dedicated corrections are necessary for the assurance of unimpaired image quality.

  11. Total Absorption Gamma-ray Spectrometer (TAGS) Intensity Distributions from INL's Gamma-Ray Spectrometry Center

    DOE Data Explorer

    Greenwood, R. E.

    A 252Cf fission-product source and the INL on-line isotope separator were used to supply isotope-separated fission-product nuclides to a total absorption -ray spectrometer. This spectrometer consisted of a large (25.4-cm diameter x 30.5-cm long) NaI(Tl) detector with a 20.3-cm deep axial well in which is placed a 300-mm2 x 1.0-mm Si detector. The spectra from the NaI(Tl) detector are collected both in the singles mode and in coincidence with the B-events detected in the Si detector. Ideally, this detector would sum all the energy of the B- rays in each cascade following the population of daughter level by B- decay, so that the event could be directly associated with a particular daughter level. However, there are losses of energy from attenuation of the rays before they reach the detector, transmission of rays through the detector, escape of secondary photons from Compton scattering, escape of rays through the detector well, internal conversion, etc., and the measured spectra are thus more complicated than the ideal case and the analysis is more complex. Analysis methods have been developed to simulate all of these processes and thus provide a direct measure of the B- intensity distribution as a function of the excitation energy in the daughter nucleus. These data yield more accurate information on the B- distribution than conventional decay-scheme studies for complex decay schemes with large decay energies, because in the latter there are generally many unobserved and observed but unplaced rays. The TAGS data have been analyzed and published [R. E. Greenwood et al., Nucl Instr. and metho. A390(1997)] for 40 fission product-nuclides to determine the B- intensity distributions. [Copied from the TAGS page at http://www.inl.gov/gammaray/spectrometry/tags.shtml]. Those values are listed on this page for quick reference.

  12. Non-parametric error distribution analysis from the laboratory calibration of various rainfall intensity gauges.

    PubMed

    Lanza, L G; Stagi, L

    2012-01-01

    The analysis of counting and catching errors of both catching and non-catching types of rain intensity gauges was recently possible over a wide variety of measuring principles and instrument design solutions, based on the work performed during the recent Field Intercomparison of Rainfall Intensity Gauges promoted by World Meteorological Organization (WMO). The analysis reported here concerns the assessment of accuracy and precision of various types of instruments based on extensive calibration tests performed in the laboratory during the first phase of this WMO Intercomparison. The non-parametric analysis of relative errors allowed us to conclude that the accuracy of the investigated RI gauges is generally high, after assuming that it should be at least contained within the limits set forth by WMO in this respect. The measuring principle exploited by the instrument is generally not very decisive in obtaining such good results in the laboratory. Rather, the attention paid by the manufacturer to suitably accounting and correcting for systematic errors and time-constant related effects was demonstrated to be influential. The analysis of precision showed that the observed frequency distribution of relative errors around their mean value is not indicative of an underlying Gaussian population, being much more peaked in most cases than can be expected from samples extracted from a Gaussian distribution. The analysis of variance (one-way ANOVA), assuming the instrument model as the only potentially affecting factor, does not confirm the hypothesis of a single common underlying distribution for all instruments. Pair-wise multiple comparison analysis revealed cases in which significant differences could be observed.

  13. The Interannual Stability of Cumulative Frequency Distributions for Convective System Size and Intensity

    NASA Technical Reports Server (NTRS)

    Mohr, Karen I.; Molinari, John; Thorncroft, Chris

    2009-01-01

    The characteristics of convective system populations in West Africa and the western Pacific tropical cyclone basin were analyzed to investigate whether interannual variability in convective activity in tropical continental and oceanic environments is driven by variations in the number of events during the wet season or by favoring large and/or intense convective systems. Convective systems were defined from Tropical Rainfall Measuring Mission (TRMM) data as a cluster of pixels with an 85-GHz polarization-corrected brightness temperature below 255 K and with an area of at least 64 square kilometers. The study database consisted of convective systems in West Africa from May to September 1998-2007, and in the western Pacific from May to November 1998-2007. Annual cumulative frequency distributions for system minimum brightness temperature and system area were constructed for both regions. For both regions, there were no statistically significant differences between the annual curves for system minimum brightness temperature. There were two groups of system area curves, split by the TRMM altitude boost in 2001. Within each set, there was no statistically significant interannual variability. Subsetting the database revealed some sensitivity in distribution shape to the size of the sampling area, the length of the sample period, and the climate zone. From a regional perspective, the stability of the cumulative frequency distributions implied that the probability that a convective system would attain a particular size or intensity does not change interannually. Variability in the number of convective events appeared to be more important in determining whether a year is either wetter or drier than normal.

  14. Atmosphere-Ocean Coupling Effect on Intense Tropical Cyclone Distribution and its Future Change with 60 km-AOGCM

    PubMed Central

    Ogata, Tomomichi; Mizuta, Ryo; Adachi, Yukimasa; Murakami, Hiroyuki; Ose, Tomoaki

    2016-01-01

    Atmosphere-ocean coupling effect on the frequency distribution of tropical cyclones (TCs) and its future change is studied using an atmosphere and ocean coupled general circulation model (AOGCM). In the present climate simulation, the atmosphere-ocean coupling in the AOGCM improves biases in the AGCM such as the poleward shift of the maximum of intense TC distribution in the Northern Hemisphere and too many intense TCs in the Southern Hemisphere. Particularly, subsurface cold water plays a key role to reduce these AGCM biases of intense TC distribution. Besides, the future change of intense TC distribution is significantly different between AOGCM and AGCM despite the same monthly SST. In the north Atlantic, subsurface warming causes larger increase in frequency of intense TCs in AOGCM than that in AGCM. Such subsurface warming in AOGCM also acts to alter large decrease of intense TC in AGCM to no significant change in AOGCM over the southwestern Indian Ocean. These results suggest that atmosphere-ocean coupling characterized by subsurface oceanic structure is responsible for more realistic intense TC distribution in the current climate simulation and gives significant impacts on its future projection. PMID:27418240

  15. Atmosphere-Ocean Coupling Effect on Intense Tropical Cyclone Distribution and its Future Change with 60 km-AOGCM

    NASA Astrophysics Data System (ADS)

    Ogata, Tomomichi; Mizuta, Ryo; Adachi, Yukimasa; Murakami, Hiroyuki; Ose, Tomoaki

    2016-07-01

    Atmosphere-ocean coupling effect on the frequency distribution of tropical cyclones (TCs) and its future change is studied using an atmosphere and ocean coupled general circulation model (AOGCM). In the present climate simulation, the atmosphere-ocean coupling in the AOGCM improves biases in the AGCM such as the poleward shift of the maximum of intense TC distribution in the Northern Hemisphere and too many intense TCs in the Southern Hemisphere. Particularly, subsurface cold water plays a key role to reduce these AGCM biases of intense TC distribution. Besides, the future change of intense TC distribution is significantly different between AOGCM and AGCM despite the same monthly SST. In the north Atlantic, subsurface warming causes larger increase in frequency of intense TCs in AOGCM than that in AGCM. Such subsurface warming in AOGCM also acts to alter large decrease of intense TC in AGCM to no significant change in AOGCM over the southwestern Indian Ocean. These results suggest that atmosphere-ocean coupling characterized by subsurface oceanic structure is responsible for more realistic intense TC distribution in the current climate simulation and gives significant impacts on its future projection.

  16. Atmosphere-Ocean Coupling Effect on Intense Tropical Cyclone Distribution and its Future Change with 60 km-AOGCM.

    PubMed

    Ogata, Tomomichi; Mizuta, Ryo; Adachi, Yukimasa; Murakami, Hiroyuki; Ose, Tomoaki

    2016-07-15

    Atmosphere-ocean coupling effect on the frequency distribution of tropical cyclones (TCs) and its future change is studied using an atmosphere and ocean coupled general circulation model (AOGCM). In the present climate simulation, the atmosphere-ocean coupling in the AOGCM improves biases in the AGCM such as the poleward shift of the maximum of intense TC distribution in the Northern Hemisphere and too many intense TCs in the Southern Hemisphere. Particularly, subsurface cold water plays a key role to reduce these AGCM biases of intense TC distribution. Besides, the future change of intense TC distribution is significantly different between AOGCM and AGCM despite the same monthly SST. In the north Atlantic, subsurface warming causes larger increase in frequency of intense TCs in AOGCM than that in AGCM. Such subsurface warming in AOGCM also acts to alter large decrease of intense TC in AGCM to no significant change in AOGCM over the southwestern Indian Ocean. These results suggest that atmosphere-ocean coupling characterized by subsurface oceanic structure is responsible for more realistic intense TC distribution in the current climate simulation and gives significant impacts on its future projection.

  17. The Intensity Distribution of Faint Gamma-Ray Bursts Detected with BATSE

    NASA Technical Reports Server (NTRS)

    Kommers, Jefferson M.; Lewin, Walter H. G.; Kouveliotou, Chryssa; vanParadus, Jan; Pendleton, Geoffrey N.; Meegan, Charles A.; Fishman, Gerald J.

    2000-01-01

    We have recently completed a search of six years of archival Burst and Transient Source Experiment (BATSE) data for gamma-ray bursts (GRBs) that were too faint to activate the real-time burst detection system running on board the spacecraft. These 'nontriggered' bursts can be combined with the 'triggered' bursts detected on board to produce a GRB intensity distribution that reaches peak fluxes a factor of approximately two lower than could be studied previously. The value of the statistic (in Euclidean space) for the bursts we detect is 0.177 +/- 0.006. This surprisingly low value is obtained because we detected very few bursts on the 4.096 s and 8.192 s timescales (where most bursts have their highest signal-to-noise ratio) that were not already detected on the 1.024 s timescale. If allowance is made for a power-law distribution of intrinsic peak luminosities, the extended peak flux distribution is consistent with models in which the redshift distribution of the gamma-ray burst rate approximately traces the star formation history of the universe. We argue that this class of models is preferred over those in which the burst rate is independent of redshift. We use the peak flux distribution to derive a limit of 10% (99% confidence) on the fraction of the total burst rate that could be contributed by a spatially homogeneous (in Euclidean space) subpopulation of burst sources, such as type Ib/c supernovae. These results lend support to the conclusions of previous studies predicting that relatively few faint 'classical' GRBs will be found below the BATSE onboard detection threshold.

  18. The Intensity Distribution of Faint Gamma-Ray Bursts Detected with BATSE

    NASA Technical Reports Server (NTRS)

    Kommers, Jefferson M.; Lewin, Walter H. G.; Kouveliotou, Chryssa; VanParadijs, Jan; Pendleton, Geoffrey N.; Meegan, Charles A.; Fishman, Gerald J.

    2000-01-01

    We have recently completed a search of 6 years of archival BATSE data for gamma-ray bursts (GRBS) that were too faint to activate the real-time burst detection system running on board the spacecraft. These "nontriggered" bursts can be combined with the "triggered" bursts detected on board to produce a GRB intensity distribution that reaches peak fluxes a factor of approximately 2 lower than could be studied previously. The value of the statistic (in Euclidean space) for the bursts we detect is 0.177 plus or minus 0.006. This surprisingly low value is obtained because we detected very few bursts on the 4.096 s and 8.192 s timescales (where most bursts have their highest signal-to-noise ratio) that were not already detected on the 1.024 s timescale. If allowance is made for a power-law distribution of intrinsic peak luminosities, the extended peak flux distribution is consistent with models in which the redshift distribution of the gamma-ray burst rate approximately traces the star formation history of the universe. We argue that this class of models is preferred over those in which the burst rate is independent of redshift. We use the peak flux distribution to derive a limit of 10% (99% confidence) on the fraction of the total burst rate that could be contributed by a spatially homogeneous (in Euclidean space) subpopulation of burst sources, such as type lb/c supernovae. These results lend support to the conclusions of previous studies predicting that relatively few faint "classical" GRBs will be found below the BATSE onboard detection threshold.

  19. Continuum-continuum transitions between resonant states using the RABITT technique

    NASA Astrophysics Data System (ADS)

    Jiménez, A.; Argenti, L.; Martín, F.

    2014-04-01

    We present a study of radiative continuum-continuum transitions in helium in the presence of doubly-excited states by using the attosecond RABITT technique beyond the Single Active Electron approximation. On the one hand, transition amplitudes between correlated continuum states are calculated both by direct numerical solution of the time-dependent Schrodinger equation as well as with a two-photon perturbative model. The effect of autoionizing states on the sideband phaseshift is thus analyzed. On the other hand, we apply the soft-photon approximation to quantify the effects the IR probe intensity on the sideband non-resonant overtone components.

  20. Basal friction evolution and crevasse distribution during the surge of Basin 3, Austfonna ice-cap - offline coupling between a continuum ice dynamic model and a discrete element model

    NASA Astrophysics Data System (ADS)

    Gong, Yongmei; Zwinger, Thomas; Åström, Jan; Gladstone, Rupert; Schellenberger, Thomas; Altena, Bas; Moore, John

    2017-04-01

    The outlet glacier at Basin 3, Austfonna ice-cap entered its active surge phase in autumn 2012. We assess the evolution of the basal friction during the surge through inverse modelling of basal friction coefficients using recent velocity observation from 2012 to 2014 in a continuum ice dynamic model Elmer/ice. The obtained basal friction coefficient distributions at different time instances are further used as a boundary condition in a discrete element model (HiDEM) that is capable of computing fracturing of ice. The inverted basal friction coefficient evolution shows a gradual 'unplugging' of the stagnant frontal area and northwards and inland expansion of the fast flowing region in the southern basin. The validation between the modeled crevasses distribution and the satellite observation in August 2013 shows a good agreement in shear zones inland and at the frontal area. Crevasse distributions of the summer before and after the glacier reached its maximum velocity in January 2013 (August 2012 and August 2014, respectively) are also evaluated. Previous studies suggest the triggering and development of the surge are linked to surface melt water penetrating through ice to form an efficient basal hydrology system thereby triggering a hydro- thermodynamic feedback. This preliminary offline coupling between a continuum ice dynamic model and a discrete element model will give a hint on future model development of linking supra-glacial to sub-glacial hydrology system.

  1. Self-Focusing and Continuum Generation in Gases

    NASA Astrophysics Data System (ADS)

    Corkum, Paul B.; Rolland, Claude

    This book attests to the fact continuum generation has become both technically and conceptually important. Discovered in 1970 (Alfano and Shapiro, 1970a, 1970b), continuum generation is a ubiquitous response of transparent materials (liquids, solids, and gases) to high-power, ultrashort-pulse radiation. This chapter highlights some of these aspects while presenting the sometimes unique characteristics of continuum generation in gases. In addition, we introduce some related results that reflect on the light-atom interaction at high intensities.

  2. Distribution of temperature elevation caused by moving high-intensity focused ultrasound transducer

    NASA Astrophysics Data System (ADS)

    Kim, Jungsoon; Jung, Jihee; Kim, Moojoon; Ha, Kanglyeol; Lee, Eunghwa; Lee, Ilkwon

    2015-07-01

    Ultrasonic thermal treatment for dermatology has been developed using a small high-intensity focused ultrasound (HIFU) transducer. The transducer moves horizontally at a constant while it emits focused ultrasound because the treatment needs a high-temperature area in skin tissue over a wide range of depths. In this paper, a tissue-mimicking phantom made of carrageenan and a thermochromic film were adopted to examine the temperature distribution in the phantom noninvasively when the focused ultrasound was irradiated from the moving transducer. The dependence of the high-temperature area on the irradiated acoustic energy and on the movement interval of the HIFU was analyzed experimentally. The results will be useful in ensuring safety and estimating the remedial value of the treatment.

  3. Optical intensity distribution of a plano-convex solid immersion mirror.

    PubMed

    Zhang, Yaoju

    2007-01-01

    Ignoring the effect of the small aperture, we deduce the optical field distribution of the so-called plano-convex solid immersion mirror with a small aperture on the apex (PC-SIM) by using the vector diffraction theory. The simulation results show that a PC-SIM, like a solid immersion lens (SIL), can achieve high resolution. Unlike the SIL, the PC-SIM can effectively reduce the spreading of the spot size with increasing distance from the interface. The size and intensity of the spot are related not only to the refractive index of the solid immersion medium but also to the structure parameter of the PC-SIM. The size of a spot smaller than a quarter wavelength can be obtained simply by optimizing the structure parameter of a PC-SIM but not by decreasing the size of the small aperture.

  4. Spatial intensity distribution of the radiative return from scattering media irradiated by a cw laser beam

    NASA Astrophysics Data System (ADS)

    Gurdev, Ljuan L.; Dreischuh, Tanja N.; Vankov, Orlin I.; Toncheva, Eleonora N.; Avramov, Lachezar A.; Stoyanov, Dimitar V.

    2016-01-01

    Experimental measurements and theoretical description have been performed of the spatial intensity distribution of the backward radiative response of tissue-like Intralipid-20% dilutions in distilled water irradiated by a collimated near-infrared cw laser beam. The investigations performed are a first step toward a complete estimation of the feasibility and potentialities of a stationary one-sided linear-strategy biomedical tomography approach to detecting characteristic inclusions (inhomogeneities, say ill places) in homogeneous highly-scattering host media (healthy tissues). The experimental results obtained are in good agreement with the derived theoretical expressions that thus would be of importance for the development and numerical modeling of stationary tomography algorithms ensuring optimally accurate data processing and interpretation.

  5. Hydrogen Balmer alpha intensity distributions and line profiles from multiple scattering theory using realistic geocoronal models

    NASA Technical Reports Server (NTRS)

    Anderson, D. E., Jr.; Meier, R. R.; Hodges, R. R., Jr.; Tinsley, B. A.

    1987-01-01

    The H Balmer alpha nightglow is investigated by using Monte Carlo models of asymmetric geocoronal atomic hydrogen distributions as input to a radiative transfer model of solar Lyman-beta radiation in the thermosphere and atmosphere. It is shown that it is essential to include multiple scattering of Lyman-beta radiation in the interpretation of Balmer alpha airglow data. Observations of diurnal variation in the Balmer alpha airglow showing slightly greater intensities in the morning relative to evening are consistent with theory. No evidence is found for anything other than a single sinusoidal diurnal variation of exobase density. Dramatic changes in effective temperature derived from the observed Balmer alpha line profiles are expected on the basis of changing illumination conditions in the thermosphere and exosphere as different regions of the sky are scanned.

  6. Hydrogen Balmer alpha intensity distributions and line profiles from multiple scattering theory using realistic geocoronal models

    NASA Technical Reports Server (NTRS)

    Anderson, D. E., Jr.; Meier, R. R.; Hodges, R. R., Jr.; Tinsley, B. A.

    1987-01-01

    The H Balmer alpha nightglow is investigated by using Monte Carlo models of asymmetric geocoronal atomic hydrogen distributions as input to a radiative transfer model of solar Lyman-beta radiation in the thermosphere and atmosphere. It is shown that it is essential to include multiple scattering of Lyman-beta radiation in the interpretation of Balmer alpha airglow data. Observations of diurnal variation in the Balmer alpha airglow showing slightly greater intensities in the morning relative to evening are consistent with theory. No evidence is found for anything other than a single sinusoidal diurnal variation of exobase density. Dramatic changes in effective temperature derived from the observed Balmer alpha line profiles are expected on the basis of changing illumination conditions in the thermosphere and exosphere as different regions of the sky are scanned.

  7. Transformation of a high-order mode-intensity distribution to a nearly Gaussian beam

    NASA Astrophysics Data System (ADS)

    Machavariani, G.; Davidson, Nir; Ishaaya, Amiel A.; Friesem, Asher A.; Hasman, Erez

    2003-11-01

    A simple method for obtaining a nearly Gaussian laser beam from a high order Hermite-Gaussian mode is presented. The method is based on separating the equal lobes of the high order mode and combining them together coherently. The method was experimentally verified with an arrangement of three mirrors, a 50% beam splitter and a phase tuning plate. The beam quality factor calculated in x-direction for the resulting output beam is 1.045, being very close to that of ideal Gaussian beam. The calculated power leakage is only 1.5%. The experimental near-field and far-field intensity distributions of the output beam have nearly Gaussian cross sections in both the x and y directions, with M2x=1.34 and M2y=1.32. With some modifications, it is possible to obtain an output beam with M2x=1.15 and no power leakage.

  8. Marine capture fisheries production and intensity of rainfall: An application of autoregressive distributed lag (ARDL) model

    NASA Astrophysics Data System (ADS)

    Fitri, Fadhilah; Toharudin, Toni; Jaya, I. Gede Nyoman Mindra

    2017-03-01

    Indonesia is a maritime country that has a high production of fish. West Java is one of the provinces which accounted for a high fish production in Indonesia with total production is 8,316,607.377 tons in 2011. The fish production in West Java has a trend and seasonal components. The trend and seasonal components is influenced by climate change. One of interesting indicator of the climate change is the change in intensity of rainfall. The increasing intensity of rainfall would be increase fish production. The influence rainfall on fishing production can be formulated in a mathematical model using Autoregressive Distributed Lag Modeling (ARDL). This method was applied because of the impact of the lag of independent variables and dependent variable that included in the model. The model informs how big the impact. The parameter estimation was conducted using ordinary least squares (OLS) and obtained adjusted R2 = 0.8265. The high fish productions in the previous period affect the decline in fish production in the next period.

  9. A Distributed Network for Intensive Longitudinal Monitoring in Metastatic Triple-Negative Breast Cancer.

    PubMed

    Blau, C Anthony; Ramirez, Arturo B; Blau, Sibel; Pritchard, Colin C; Dorschner, Michael O; Schmechel, Stephen C; Martins, Timothy J; Mahen, Elisabeth M; Burton, Kimberly A; Komashko, Vitalina M; Radenbaugh, Amie J; Dougherty, Katy; Thomas, Anju; Miller, Christopher P; Annis, James; Fromm, Jonathan R; Song, Chaozhong; Chang, Elizabeth; Howard, Kellie; Austin, Sharon; Schmidt, Rodney A; Linenberger, Michael L; Becker, Pamela S; Senecal, Francis M; Mecham, Brigham H; Lee, Su-In; Madan, Anup; Ronen, Roy; Dutkowski, Janusz; Heimfeld, Shelly; Wood, Brent L; Stilwell, Jackie L; Kaldjian, Eric P; Haussler, David; Zhu, Jingchun

    2016-01-01

    Accelerating cancer research is expected to require new types of clinical trials. This report describes the Intensive Trial of OMics in Cancer (ITOMIC) and a participant with triple-negative breast cancer metastatic to bone, who had markedly elevated circulating tumor cells (CTCs) that were monitored 48 times over 9 months. A total of 32 researchers from 14 institutions were engaged in the patient's evaluation; 20 researchers had no prior involvement in patient care and 18 were recruited specifically for this patient. Whole-exome sequencing of 3 bone marrow samples demonstrated a novel ROS1 variant that was estimated to be present in most or all tumor cells. After an initial response to cisplatin, a hypothesis of crizotinib sensitivity was disproven. Leukapheresis followed by partial CTC enrichment allowed for the development of a differential high-throughput drug screen and demonstrated sensitivity to investigational BH3-mimetic inhibitors of BCL-2 that could not be tested in the patient because requests to the pharmaceutical sponsors were denied. The number and size of CTC clusters correlated with clinical status and eventually death. Focusing the expertise of a distributed network of investigators on an intensively monitored patient with cancer can generate high-resolution views of the natural history of cancer and suggest new opportunities for therapy. Optimization requires access to investigational drugs. Copyright © 2016 by the National Comprehensive Cancer Network.

  10. Evaluation of Dose Distribution in Intensity Modulated Radiosurgery for Lung Cancer under Condition of Respiratory Motion

    PubMed Central

    Yoon, Mee Sun; Jeong, Jae-Uk; Nam, Taek-Keun; Ahn, Sung-Ja; Chung, Woong-Ki; Song, Ju-Young

    2016-01-01

    The dose of a real tumor target volume and surrounding organs at risk (OARs) under the effect of respiratory motion was calculated for a lung tumor plan, based on the target volume covering the whole tumor motion range for intensity modulated radiosurgery (IMRS). Two types of IMRS plans based on simulated respiratory motion were designed using humanoid and dynamic phantoms. Delivery quality assurance (DQA) was performed using ArcCHECK and MapCHECK2 for several moving conditions of the tumor and the real dose inside the humanoid phantom was evaluated using the 3DVH program. This evaluated dose in the tumor target and OAR using the 3DVH program was higher than the calculated dose in the plan, and a greater difference was seen for the RapidArc treatment than for the standard intensity modulated radiation therapy (IMRT) with fixed gantry angle beams. The results of this study show that for IMRS plans based on target volume, including the whole tumor motion range, tighter constraints of the OAR should be considered in the optimization process. The method devised in this study can be applied effectively to analyze the dose distribution in the real volume of tumor target and OARs in IMRT plans targeting the whole tumor motion range. PMID:27648949

  11. Eleven-Week Preparation Involving Polarized Intensity Distribution Is Not Superior to Pyramidal Distribution in National Elite Rowers.

    PubMed

    Treff, Gunnar; Winkert, Kay; Sareban, Mahdi; Steinacker, Jürgen M; Becker, Martin; Sperlich, Billy

    2017-01-01

    Polarized (POL) training intensity distribution (TID) emphasizes high-volume low-intensity exercise in zone (Z)1 (< first lactate threshold) with a greater proportion of high-intensity Z3 (>second lactate threshold) compared to Z2 (between first and second lactate threshold). In highly trained rowers there is a lack of prospective controlled evidence whether POL is superior to pyramidal (PYR; i.e., greater volume in Z1 vs. Z2 vs. Z3) TID. The aim of the study was to compare the effect of POL vs. PYR TID in rowers during an 11-wk preparation period. Fourteen national elite male rowers participated (age: 20 ± 2 years, maximal oxygen uptake ([Formula: see text]O2max): 66 ± 5 mL/min/kg). The sample was split into PYR and POL by varying the percentage spent in Z2 and Z3 while Z1 was clamped to ~93% and matched for total and rowing volume. Actual TIDs were based on time within heart rate zones (Z1 and Z2) and duration of Z3-intervals. The main outcome variables were average power in 2,000 m ergometer-test (P2,000 m), power associated with 4 mmol/L [blood lactate] (P4[BLa]), and [Formula: see text]O2max. To quantify the level of polarization, we calculated a Polarization-Index as log (%Z1 × %Z3 / %Z2). PYR and POL did not significantly differ regarding rowing or total volume, but POL had a higher percentage of Z3 intensities (6 ± 3 vs. 2 ± 1%; p < 0.005) while Z2 was lower (1 ± 1 vs. 3 ± 2%; p < 0.05) and Z1 was similar (94 ± 3 vs. 93 ± 2%, p = 0.37). Consequently, Polarization-Index was significantly higher in POL (3.0 ± 0.7 vs. 1.9 ± 0.4 a.u.; p < 0.01). P2,000 m did not significantly change with PYR (1.5 ± 1.7%, p = 0.06) nor POL (1.5 ± 2.6%, p = 0.26). [Formula: see text]2max did not change (1.7 ± 5.6%, p = 0.52 or 0.6 ± 2.6, p = 0.67) and a small increase in P4[BLa] was observed in PYR only (1.9 ± 4.8%, p = 0.37 or -0.5 ± 4.1%, p = 0.77). Changes from pre to post were not significantly different between groups in any performance measure. POL did not

  12. Eleven-Week Preparation Involving Polarized Intensity Distribution Is Not Superior to Pyramidal Distribution in National Elite Rowers

    PubMed Central

    Treff, Gunnar; Winkert, Kay; Sareban, Mahdi; Steinacker, Jürgen M.; Becker, Martin; Sperlich, Billy

    2017-01-01

    Polarized (POL) training intensity distribution (TID) emphasizes high-volume low-intensity exercise in zone (Z)1 (< first lactate threshold) with a greater proportion of high-intensity Z3 (>second lactate threshold) compared to Z2 (between first and second lactate threshold). In highly trained rowers there is a lack of prospective controlled evidence whether POL is superior to pyramidal (PYR; i.e., greater volume in Z1 vs. Z2 vs. Z3) TID. The aim of the study was to compare the effect of POL vs. PYR TID in rowers during an 11-wk preparation period. Fourteen national elite male rowers participated (age: 20 ± 2 years, maximal oxygen uptake (V˙O2max): 66 ± 5 mL/min/kg). The sample was split into PYR and POL by varying the percentage spent in Z2 and Z3 while Z1 was clamped to ~93% and matched for total and rowing volume. Actual TIDs were based on time within heart rate zones (Z1 and Z2) and duration of Z3-intervals. The main outcome variables were average power in 2,000 m ergometer-test (P2,000 m), power associated with 4 mmol/L [blood lactate] (P4[BLa]), and V˙O2max. To quantify the level of polarization, we calculated a Polarization-Index as log (%Z1 × %Z3 / %Z2). PYR and POL did not significantly differ regarding rowing or total volume, but POL had a higher percentage of Z3 intensities (6 ± 3 vs. 2 ± 1%; p < 0.005) while Z2 was lower (1 ± 1 vs. 3 ± 2%; p < 0.05) and Z1 was similar (94 ± 3 vs. 93 ± 2%, p = 0.37). Consequently, Polarization-Index was significantly higher in POL (3.0 ± 0.7 vs. 1.9 ± 0.4 a.u.; p < 0.01). P2,000 m did not significantly change with PYR (1.5 ± 1.7%, p = 0.06) nor POL (1.5 ± 2.6%, p = 0.26). V˙O2max did not change (1.7 ± 5.6%, p = 0.52 or 0.6 ± 2.6, p = 0.67) and a small increase in P4[BLa] was observed in PYR only (1.9 ± 4.8%, p = 0.37 or −0.5 ± 4.1%, p = 0.77). Changes from pre to post were not significantly different between groups in any performance measure. POL did not prove to be superior to PYR, possibly due to

  13. Cassini observation of Jovian anomalous continuum radiation

    NASA Astrophysics Data System (ADS)

    Ye, Sheng-Yi; Gurnett, D. A.; Menietti, J. D.; Kurth, W. S.; Fischer, G.; Schippers, P.; Hospodarsky, G. B.

    2012-04-01

    Jovian anomalous continuum is a narrowband electromagnetic radiation near 10 kHz that can escape from Jupiter's magnetosphere to interplanetary space. One possible source mechanism is the magnetosheath re-radiation of the Jovian low frequency radio emissions such as the quasiperiodic (QP) radio emissions, broadband kilometric radiation (bKOM) and non-thermal continuum. Jovian anomalous continuum was consistently observed by the Cassini Radio and Plasma Wave Science instrument from 2000 to 2004, right before the Saturn orbit insertion, which means the radiation can be detected as far as 8 AU away from Jupiter. An analysis of intensity versus radial distance shows that the Jovian anomalous continuum has a line source rather than a point source, consistent with the theory that the emission is radiated by the whole length of the magnetotail. The emissions are modulated at the system III period of Jupiter and are unpolarized. Since the lower cutoff frequency of the anomalous continuum is related to the plasma frequency in the magnetosheath of Jupiter, which is a function of solar wind density, the recurrent variations of the lower cutoff frequency can be used as a remote diagnostic of the solar wind condition at Jupiter. We propose that the frequency dispersion, a unique characteristic of the anomalous continuum, is likely a comprehensive effect of both the slow group velocity near the local plasma frequency and the refraction/scattering of the waves by density structures as they propagate in the magnetosheath.

  14. Predicting Distribution and Inter-Annual Variability of Tropical Cyclone Intensity from a Stochastic, Multiple-Linear Regression Model

    NASA Astrophysics Data System (ADS)

    Lee, C. Y.; Tippett, M. K.; Sobel, A. H.; Camargo, S. J.

    2014-12-01

    We are working towards the development of a new statistical-dynamical downscaling system to study the influence of climate on tropical cyclones (TCs). The first step is development of an appropriate model for TC intensity as a function of environmental variables. We approach this issue with a stochastic model consisting of a multiple linear regression model (MLR) for 12-hour intensity forecasts as a deterministic component, and a random error generator as a stochastic component. Similar to the operational Statistical Hurricane Intensity Prediction Scheme (SHIPS), MLR relates the surrounding environment to storm intensity, but with only essential predictors calculated from monthly-mean NCEP reanalysis fields (potential intensity, shear, etc.) and from persistence. The deterministic MLR is developed with data from 1981-1999 and tested with data from 2000-2012 for the Atlantic, Eastern North Pacific, Western North Pacific, Indian Ocean, and Southern Hemisphere basins. While the global MLR's skill is comparable to that of the operational statistical models (e.g., SHIPS), the distribution of the predicted maximum intensity from deterministic results has a systematic low bias compared to observations; the deterministic MLR creates almost no storms with intensities greater than 100 kt. The deterministic MLR can be significantly improved by adding the stochastic component, based on the distribution of random forecasting errors from the deterministic model compared to the training data. This stochastic component may be thought of as representing the component of TC intensification that is not linearly related to the environmental variables. We find that in order for the stochastic model to accurately capture the observed distribution of maximum storm intensities, the stochastic component must be auto-correlated across 12-hour time steps. This presentation also includes a detailed discussion of the distributions of other TC-intensity related quantities, as well as the inter

  15. Generation of Initial Kinetic Distributions for Simulation of Long-Pulse Charged Particle Beams with High Space-Charge intensity

    SciTech Connect

    Lund, Steven M.; Kikuchi, Takashi; Davidson, Ronald C.

    2007-04-03

    Self-consistent Vlasov-Poisson simulations of beams with high space-charge intensity often require specification of initial phase-space distributions that reflect properties of a beam that is well adapted to the transport channel--both in terms of low-order rms (envelope) properties as well as the higher-order phase-space structure. Here, we first review broad classes of kinetic distributions commonly in use as initial Vlasov distributions in simulations of unbunched or weakly bunched beams with intense space-charge fields including: the Kapchinskij-Vladimirskij (KV) equilibrium, continuous-focusing equilibria with specific detailed examples, and various non-equilibrium distributions, such as the semi-Gaussian distribution and distributions formed from specified functions of linear-field Courant-Snyder invariants. Important practical details necessary to specify these distributions in terms of usual accelerator inputs are presented in a unified format. Building on this presentation, a new class of approximate initial kinetic distributions are constructed using transformations that preserve linear-focusing single-particle Courant-Snyder invariants to map initial continuous-focusing equilibrium distributions to a form more appropriate for non-continuous focusing channels. Self-consistent particle-in-cell simulations are employed to show that the approximate initial distributions generated in this manner are better adapted to the focusing channels for beams with high space-charge intensity. This improved capability enables simulation applications that more precisely probe intrinsic stability properties and machine performance.

  16. Generation of initial Vlasov distributions for simulation of charged particle beams with high space-charge intensity

    SciTech Connect

    Lund, S M; Kikuchi, T; Davidson, R C

    2007-04-12

    Self-consistent Vlasov simulations of beams with high space-charge intensity often require specification of initial phase-space distributions that reflect properties of a beam that is well adapted to the transport channel, both in terms of low-order rms (envelope) properties as well as the higher-order phase-space structure. Here, we first review broad classes of distributions commonly in use as initial Vlasov distributions in simulations of beams with intense space-charge fields including: the Kapchinskij-Vladimirskij (KV) equilibrium, continuous-focusing equilibria with specific detailed examples, and various non-equilibrium distributions, such as the semi-Gaussian distribution and distributions formed from specified functions of linear-field Courant-Snyder invariants. Important practical details necessary to specify these distributions in terms of usual accelerator inputs are presented in a unified format. Building on this presentation, a new class of approximate initial distributions are constructed using transformations that preserve linear-focusing single-particle Courant-Snyder invariants to map initial continuous-focusing equilibrium distributions to a form more appropriate for non-continuous focusing channels. Self-consistent particle-in-cell simulations are employed to show that the approximate initial distributions generated in this manner are better adapted to the focusing channels for beams with high space-charge intensity. This improved capability enables simulation applications that more precisely probe intrinsic stability properties and machine performance.

  17. Tsunami source parameters estimated from slip distribution and their relation to tsunami intensity

    NASA Astrophysics Data System (ADS)

    Bolshakova, Anna; Nosov, Mikhail; Kolesov, Sergey

    2015-04-01

    Estimation of the level of tsunami hazard on the basis of earthquake moment magnitude often fails. The most important reason for this is that tsunamis are related to earthquakes in a complex and ambiguous way. In order to reveal a measure of tsunamigenic potential of an earthquake that would be better than moment magnitude of earthquake we introduce a set of tsunami source parameters that can be calculated from co-seismic ocean-bottom deformation and bathymetry. We consider more than two hundred ocean-bottom earthquakes (1923-2014) those for which detailed slip distribution data (Finite Fault Model) are available on USGS, UCSB, Caltech, and eQuake-RC sites. Making use of the Okada formulae the vector fields of co-seismic deformation of ocean bottom are estimated from the slip distribution data. Taking into account bathymetry (GEBCO_08) we determine tsunami source parameters such as double amplitude of bottom deformation, displaced water volume, potential energy of initial elevation, etc. The tsunami source parameters are examined as a function of earthquake moment magnitude. The contribution of horisontal component of ocean bottom deformation to tsunami generation is investigated. We analyse the Soloviev-Imamura tsunami intensity as a function of tsunami source parameters. The possibility of usage of tsunami source parameters instead of moment magnitude in tsunami warning is discussed. This work was supported by the Russian Foundation for Basic Research, project 14-05-31295

  18. Surface-emitting, distributed-feedback diode lasers with uniform near-field intensity profile

    NASA Astrophysics Data System (ADS)

    Lopez, James; Kasraian, Masoud; Botez, Dan

    1998-10-01

    Theoretical analysis of second-order surface-emitting, complex-coupled distributed feedback diode lasers with first-order distributed Bragg reflectors (DBR) is presented. The DBR reflectors are shown to insure simultaneous operation in a virtually uniform near-field profile with high efficiency and adequate intermodal discrimination. Such devices display symmetric-mode (single-lobe) surface emission with relatively high external differential quantum efficiency (30%), low gain threshold (18 cm-1), and <8% near-field intensity profile variations (in the longitudinal direction). The devices have the potential to provide >100 mW of stable, single-mode cw power, significantly higher than it is possible with vertical-cavity surface-emitting lasers. It is also shown that the device studied here can be combined with a resonant optical waveguide array device to produce a 2D uniform near-field surface-emitting source capable of providing greater than 1 W cw power in a stable, single-lobed beam.

  19. OBSERVATION OF THE FAR-ULTRAVIOLET CONTINUUM BACKGROUND WITH SPEAR/FIMS

    SciTech Connect

    Seon, Kwang-Il; Han, Wonyong; Shinn, Jongho; Kim, Il-Joong; Edelstein, Jerry; Korpela, Eric; Witt, Adolf; Min, Kyoung-Wook; Park, Jae-Woo

    2011-10-01

    We present the general properties of the far-ultraviolet (FUV; 1370-1710 A) continuum background over most of the sky, obtained with the Spectroscopy of Plasma Evolution from Astrophysical Radiation (SPEAR) instrument (also known as FIMS), flown aboard the STSAT-1 satellite mission. We find that the diffuse FUV continuum intensity is well correlated with N{sub HI}, 100 {mu}m, and H{alpha} intensities but anti-correlated with soft X-ray intensity. The correlation of the diffuse background with the direct stellar flux is weaker than the correlation with other parameters. The continuum spectra are relatively flat. However, a weak softening of the FUV spectra toward some sight lines, mostly at high Galactic latitudes, is found not only in direct stellar but also in diffuse background spectra. The diffuse background is relatively softer than the direct stellar spectrum. We also find that the diffuse FUV background averaged over the sky has a bit softer spectrum compared to direct stellar radiation. A map of the ratio of 1370-1520 A to 1560-1710 A band intensity shows that the sky is divided into roughly two parts. However, this map shows a lot of patchy structures on small scales. The spatial variation of the hardness ratio seems to be largely determined by the longitudinal distribution of OB-type stars in the Galactic plane. A correlation of the hardness ratio with the FUV intensity is found at high intensities but an anti-correlation is found at low intensities. We also find evidence that the FUV intensity distribution is log-normal in nature.

  20. Assessment the Trend of Inequality in the Distribution of Intensive Care Beds in Iran: Using GINI Index

    PubMed Central

    Meskarpour-Amiri, Mohammad; Mehdizadeh, Parisa; Barouni, Mohsen; Dopeykar, Nooredin; Ramezanian, Maryam

    2014-01-01

    Background and Aim: While most of the published researches have reported the amount of inequity in geographical distribution of important health resources, only a small number of studies have focused on the trend of inequality in the distribution of these resources. The purpose of this study was to determine the trend of inequality in the distribution of intensive care beds in Iran during 2010 to 2012 by using the Gini coefficient. Methods: This is a cross-sectional research conducted in 2013. The changes over three years (2010 to 2012) were calculated by Gini coefficient to investigate the trend of inequality in geographical distribution of intensive care beds (CCU, ICU and NICU). Results: The Gini coefficient for CCU beds was calculated as 0.02, 0.04 and 0.06 in 2010, 2011 and 2012, respectively. The Gini coefficient for ICU beds was calculated as 0.03, 0.05 and 0.05 in 2010, 2011 and 2012, respectively. Also, the Gini coefficient for NICU bed was calculated as 0.02, 0.03 and 0.04 in 2010, 2011 and 2012, respectively. Conclusion: Regarding to Gini coefficient, the trend of inequality was increased in the distribution of intensive care beds in Iran. Particularly, the inequalities in distribution of CCU beds were significantly increased during past years. In fact, if this trend of inequality continues, the distribution of intensive care beds will be extremely unequal in the next five years in Iran. PMID:25363104

  1. 11-kW direct diode laser system with homogenized 55 × 20 mm2 Top-Hat intensity distribution

    NASA Astrophysics Data System (ADS)

    Köhler, Bernd; Noeske, Axel; Kindervater, Tobias; Wessollek, Armin; Brand, Thomas; Biesenbach, Jens

    2007-02-01

    In comparison with other laser systems diode lasers are characterized by a unique overall efficiency, a small footprint and high reliability. However, one major drawback of direct diode laser systems is the inhomogeneous intensity distribution in the far field. Furthermore the output power of current commercially available systems is limited to about 6 kW. We report on a diode laser system with 11 kW output power at a single wavelength of 940 nm aiming for customer specific large area treatment. To the best of our knowledge this is the highest output power reported so far for a direct diode laser system. In addition to the high output power the intensity distribution of the laser beam is homogenized in both axes leading to a 55 x 20 mm2 Top-Hat intensity profile at a working distance of 400 mm. Homogeneity of the intensity distribution is better than 90%. The intensity in the focal plane is 1 kW/cm2. We will present a detailed characterization of the laser system, including measurements of power, power stability and intensity distribution of the homogenized laser beam. In addition we will compare the experimental data with the results of non-sequential raytracing simulations.

  2. Modeling the neutral hydrogen distribution in the post-reionization Universe: intensity mapping

    SciTech Connect

    Villaescusa-Navarro, Francisco; Viel, Matteo; Datta, Kanan K.; Choudhury, T. Roy E-mail: viel@oats.inaf.it E-mail: tirth@ncra.tifr.res.in

    2014-09-01

    We model the distribution of neutral hydrogen (HI) in the post-reionization era and investigate its detectability in 21 cm intensity mapping with future radio telescopes like the Square Kilometer array (SKA). We rely on high resolution hydrodynamical N-body simulations that have a state-of-the-art treatment of the low density photoionized gas in the inter-galactic medium (IGM). The HI is assigned a-posteriori to the gas particles following two different approaches: a halo-based method in which HI is assigned only to gas particles residing within dark matter halos; a particle-based method that assigns HI to all gas particles using a prescription based on the physical properties of the particles. The HI statistical properties are then compared to the observational properties of Damped Lyman-α Absorbers (DLAs) and of lower column density systems and reasonable good agreement is found for all the cases. Among the halo-based method, we further consider two different schemes that aim at reproducing the observed properties of DLAs by distributing HI inside halos: one of this results in a much higher bias for DLAs, in agreement with recent observations, which boosts the 21 cm power spectrum by a factor ∼ 4 with respect to the other recipe. Furthermore, we quantify the contribution of HI in the diffuse IGM to both Ω{sub HI} and the HI power spectrum finding to be subdominant in both cases. We compute the 21 cm power spectrum from the simulated HI distribution and calculate the expected signal for both SKA1-mid and SKA1-low configurations at 2.4 ≤ z ≤ 4. We find that SKA will be able to detect the 21 cm power spectrum, in the non-linear regime, up to k ∼ 1 h/Mpc for SKA1-mid and k ∼ 5 h/Mpc for SKA1-low with 100 hours of observations. We also investigate the perspective of imaging the HI distribution. Our findings indicate that SKA1-low could detect the most massive HI peaks with a signal to noise ratio (SNR) higher than 5 for an observation time of about 1000

  3. Beam characterization of FLASH from beam profile measurement by intensity transport equation and reconstruction of the Wigner distribution function

    NASA Astrophysics Data System (ADS)

    Schäfer, Bernd; Mey, Tobias; Mann, Klaus; Keitel, Barbara; Kreis, Svea; Kuhlmann, Marion; Plönjes, Elke; Tiedtke, Kai

    2013-05-01

    Beam parameters of the free-electron laser FLASH @13.5 nm in two different operation modes were determined from beam profile measurements and subsequent reconstruction of the Wigner distribution function behind the ellipsoidal focusing mirror at beamline BL2. 40 two-dimensional single pulse intensity distributions were recorded at each of 65 axial positions around the waist of the FEL beam with a magnifying EUV sensitized CCD camera. From these beam profile data the Wigner distribution function based on different levels of averaging could be reconstructed by an inverse Radon transform. For separable beams this yields the complete Wigner distribution, and for beams with zero twist the information is still sufficient for wavefront determination and beam propagation through stigmatic systems. The obtained results are compared to wavefront reconstructions based on the transport of intensity equation. A future setup for Wigner distribution measurements of general beams is discussed.

  4. Solar radio continuum storms

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Radio noise continuum emission observed in metric and decametric wave frequencies is discussed. The radio noise is associated with actively varying sunspot groups accompanied by the S-component of microwave radio emissions. It is shown that the S-component emission in microwave frequencies generally occurs several days before the emission of the noise continuum storms of lower frequencies. It is likely that energetic electrons, 10 to 100 Kev, accelerated in association with the variation of sunspot magnetic fields, are the sources of the radio emissions. A model is considered to explain the relation of burst storms on radio noise. An analysis of the role of energetic electrons on the emissions of both noise continuum and type III burst storms is presented. It is shown that instabilities associated with the electrons and their relation to their own stabilizing effects are important in interpreting both of these storms.

  5. Continuum capture in the three-body problem

    SciTech Connect

    Sellin, I A

    1980-01-01

    The three-body problem, especially the problem of electron capture to the continuum in heavy particle collisions is reviewed. Major topics covered include: second born-induced asymmetry in electron capture to the continuum; historical context, links to other tests of atomic scattering theory; experiments characterizing the velocity distribution of ECC electrons; other atomic physics tests of high velocity Born expansions; atom capture; capture by positrons; and pion capture to the continuum. (GHT)

  6. Real Distribution of the Coronal Green Line Intensity and Modelling Study of Galactic Cosmic Ray Propagation

    NASA Astrophysics Data System (ADS)

    Gushchina, R. T.; Alania, M. V.; Gil, A.; Iskra, K.; Siluszyk, M.

    2003-07-01

    transport equation of galactic cosmic rays (GCR) has been numerically solved for different qA>0 (1996) and qA<0 (1987) epochs assuming that free path of GCR scattering in the interplanetary space is controlled by the Sun's coronal green line intensity (CGLI). We found some distinctions in the distribution of the expected heliolatitudinal gradients of GCR for two and three dimensional interplanetary magnetic field. INTRODUCTION. modulation of GCR in the interplanetary space is generally determined by four processesdiffusion, convection, drift and energy change of GCR particles due to interaction with the solar wind. The joint effect of all above mentioned processes result the 11year variation of GCR. In papers [1-3] are assumed that the general reason of the 11-year variation of GCR in the energy range more than 1 GeV is different structure of the irregularities of the IMF in the maxima and minima epochs of solar activity (SA) caused the radical changes of the dependence of diffusion coefficient on the rigidity of GCR particles. EXPERIMENTAL DATA AND METHOD OF INVESTIGATION. experimental data of sunspot numbers, sunspots' areas and CGLI (λ = 5303˚) show a considerable changes during the 11-year cycle of SA, while e.g. A the changes of the solar wind velocity are not so noticeable [4, 5]. An attempt to take into account influences of the real distributions of the sunspot's areas and the Sun's CGLI on the modulation of GCR considering delay time of the phenomena in the interplanetary space with respect to the processes on the Sun have been undertaken in papers [6-8]. One of parameters of SA contentiously observed on the Earth is the Sun's CGLI. One can suppose that a modulation of GCR by some means is controlled by the changes of the CGLI; particularly there is assumed that a scattering free path of GCR transport is related with the

  7. Examining the Psychosis Continuum

    PubMed Central

    DeRosse, Pamela; Karlsgodt, Katherine H.

    2015-01-01

    The notion that psychosis may exist on a continuum with normal experience has been proposed in multiple forms throughout the history of psychiatry. However, in recent years there has been an exponential increase in efforts aimed at elucidating what has been termed the ‘psychosis continuum’. The present review seeks to summarize some of the more basic characteristics of this continuum and to present some of the recent findings that provide support for its validity. While there is still considerable work to be done, the emerging data holds considerable promise for advancing our understanding of both risk and resilience to psychiatric disorders characterized by psychosis. PMID:26052479

  8. Characterization of the fast electrons distribution produced in a high intensity laser target interaction

    SciTech Connect

    Westover, B.; Chen, C. D.; Patel, P. K.; McLean, H.; Beg, F. N.

    2014-03-15

    Experiments on the Titan laser (∼150 J, 0.7 ps, 2 × 10{sup 20} W cm{sup −2}) at the Lawrence Livermore National Laboratory were carried out in order to study the properties of fast electrons produced by high-intensity, short pulse laser interacting with matter under conditions relevant to Fast Ignition. Bremsstrahlung x-rays produced by these fast electrons were measured by a set of compact filter-stack based x-ray detectors placed at three angles with respect to the target. The measured bremsstrahlung signal allows a characterization of the fast electron beam spectrum, conversion efficiency of laser energy into fast electron kinetic energy and angular distribution. A Monte Carlo code Integrated Tiger Series was used to model the bremsstrahlung signal and infer a laser to fast electron conversion efficiency of 30%, an electron slope temperature of about 2.2 MeV, and a mean divergence angle of 39°. Simulations were also performed with the hybrid transport code ZUMA which includes fields in the target. In this case, a conversion efficiency of laser energy to fast electron energy of 34% and a slope temperature between 1.5 MeV and 4 MeV depending on the angle between the target normal direction and the measuring spectrometer are found. The observed temperature of the bremsstrahlung spectrum, and therefore the inferred electron spectrum are found to be angle dependent.

  9. Solar Intensity Distributing and Convolving Optic (SIDCO) Concept for the CLARREO Reflected Solar Imaging Spectrometer (RSIS)

    NASA Astrophysics Data System (ADS)

    Matthews, G.; Itt Geospatial Systems Climate Calibration Group

    2010-12-01

    The CLARREO mission has outlined some preliminary requirements for a space based spectrometer to measure visible to near infra-red Earth albedo with a 0.3% absolute accuracy, 0.1%/decade calibration stability and a 10km footprint size at nadir. It is well known that some Earth viewing optics undergo significant degradation at solar wavelengths when in orbit which is not directly detectable using onboard calibration sources. This makes the requirements for CLARREO very challenging, requiring the development of new instrumental concepts in order to meet the goals required. A new type of telescope system is hence proposed that uses raster scan data from the Sun as its primary calibration metric. The 10-5 attenuation necessary for Earth viewing optics to view the Sun directly is achieved using the new concept of a Solar Intensity Distributing and Convolving Optic (SIDCO), whose degradation itself is monitored to very high accuracy and precision. The proposed instrument requires no more moving parts or gimbals than those used on the long running CERES instruments. It also provides redundancy in order to continue benchmark albedo measurements even during the instruments solar calibration periods. Such redundancy also allows continual monitoring of the incoming solar spectrum.

  10. Calculation of the light intensity distribution reflected by a spherical cube corner retroreflector array

    NASA Astrophysics Data System (ADS)

    Wang, T.; Wang, W.; Geng, D.; Du, P.; Gong, M.

    2014-07-01

    Because the light intensity distribution (LID) reflected by a spherical cube corner retroreflector array (SCCRA) is of great significance for the detection of the remote laser ranging to receive laser pulse echo precisely and to accomplish the function outstandingly, it is vital to find a method to calculate the LID reflected by SCCRAs with different structural parameters for the SCCRA design. Besides, considering that the reflected light goes through a complex optical system (COS) described by ABCD matrix before it reaches the detector, the method to calculate the LID should be suitable for the COS. This article derives formulae to calculate LID reflected by a SCCRA based on the lens-system diffraction formula of S.A. Collins. In the process of deriving, coordinate transformation matrixes and vector formulations are applied and the dihedral offsets are taken into account. Because the structural parameters of the SCCRA and the expression of the ABCD matrix of the COS are not limited in the deriving process, these formulae are suitable for calculation of the LID reflected by different SCCRA and going through different COS. In addition, computer simulations are applied to explain clearly how to get the LID of a SCCRA by the formulae derived in this paper.

  11. Local influence of south-east France topography and land cover on the distribution and characteristics of intense rainfall cells

    NASA Astrophysics Data System (ADS)

    Renard, Florent

    2016-01-01

    The Greater Lyon area is strongly built up, grouping 58 communes and a population of 1.3 million in approximately 500 km2. The flood risk is high as the territory is crossed by two large watercourses and by streams with torrential flow. Floods may also occur in case of runoff after heavy rain or because of a rise in the groundwater level. The whole territory can therefore be affected, and it is necessary to possess in-depth knowledge of the depths, causes and consequences of rainfall to achieve better management of precipitation in urban areas and to reduce flood risk. This study is thus focused on the effects of topography and land cover on the occurrence, intensity and area of intense rainfall cells. They are identified by local radar meteorology (C-band) combined with a processing algorithm running in a geographic information system (GIS) which identified 109,979 weighted mean centres of them in a sample composed of the five most intense rainfall events from 2001 to 2005. First, analysis of spatial distribution at an overall scale is performed, completed by study at a more detailed scale. The results show that the distribution of high-intensity rainfall cells is spread in cluster form. Subsequently, comparison of intense rainfall cells with the topography shows that cell density is closely linked with land slope but that, above all, urbanised zones feature nearly twice as many rainfall cells as farm land or forest, with more intense intensity.

  12. Local influence of south-east France topography and land cover on the distribution and characteristics of intense rainfall cells

    NASA Astrophysics Data System (ADS)

    Renard, Florent

    2017-04-01

    The Greater Lyon area is strongly built up, grouping 58 communes and a population of 1.3 million in approximately 500 km2. The flood risk is high as the territory is crossed by two large watercourses and by streams with torrential flow. Floods may also occur in case of runoff after heavy rain or because of a rise in the groundwater level. The whole territory can therefore be affected, and it is necessary to possess in-depth knowledge of the depths, causes and consequences of rainfall to achieve better management of precipitation in urban areas and to reduce flood risk. This study is thus focused on the effects of topography and land cover on the occurrence, intensity and area of intense rainfall cells. They are identified by local radar meteorology (C-band) combined with a processing algorithm running in a geographic information system (GIS) which identified 109,979 weighted mean centres of them in a sample composed of the five most intense rainfall events from 2001 to 2005. First, analysis of spatial distribution at an overall scale is performed, completed by study at a more detailed scale. The results show that the distribution of high-intensity rainfall cells is spread in cluster form. Subsequently, comparison of intense rainfall cells with the topography shows that cell density is closely linked with land slope but that, above all, urbanised zones feature nearly twice as many rainfall cells as farm land or forest, with more intense intensity.

  13. The Continuum of Listening

    ERIC Educational Resources Information Center

    Rud, A. G.; Garrison, Jim

    2007-01-01

    The distinction between "apophatic" and "cataphatic" listening is defined and analyzed. "Apophatic" listening is more or less devoid of cognitivist claims, whereas "cataphatic" listening involves cognition and questioning. Many of the papers in this volume are discussed along the continuum determined by these two types of listening.…

  14. The Creativity Continuum

    ERIC Educational Resources Information Center

    Walling, Donovan R.

    2009-01-01

    Children are innately creative, and the youngest often are the most original because they have yet to be influenced by the creativity of others. One way to think of creative expression is as a continuum. At one end is originality, or the creation of something wholly new, "original." At the other end is replication, or the re-creation of something…

  15. The Creativity Continuum

    ERIC Educational Resources Information Center

    Walling, Donovan R.

    2009-01-01

    Children are innately creative, and the youngest often are the most original because they have yet to be influenced by the creativity of others. One way to think of creative expression is as a continuum. At one end is originality, or the creation of something wholly new, "original." At the other end is replication, or the re-creation of something…

  16. Manipulation of image intensity distribution at 7.0 T: passive RF shimming and focusing with dielectric materials.

    PubMed

    Yang, Qing X; Mao, Weihua; Wang, Jinghua; Smith, Michael B; Lei, Hao; Zhang, Xiaoliang; Ugurbil, Kamil; Chen, Wei

    2006-07-01

    To investigate the effects of high dielectric material padding on RF field distribution in the human head at 7.0 T, and demonstrate the feasibility and effectiveness of RF passive shimming and focusing with such an approach. The intensity distribution changes of gradient-recalled-echo (GRE) and spin-echo (SE) images of a human head acquired with water pads (dielectric constant = 78) placed in specified configurations around the head at 7.0 T were evaluated and compared with computer simulation results using the finite difference time domain (FDTD) method. The contributions to the B(1) field distribution change from the displacement current and conductive current of a given configuration of dielectric padding were determined with computer simulations. MR image intensity distribution in the human head with an RF coil at 7.0 T can be changed drastically by placing water pads around the head. Computer simulations reveal that the high permittivity of water pads results in a strong displacement current that enhances image intensity in the nearby region and alters the intensity distribution of the entire brain. The image intensity distribution in the human head at ultra-high field strengths can be effectively manipulated with high permittivity padding. Utilizing this effect, the B(1) field inside the human head of a given RF coil can be adjusted to reduce the B(1) field inhomogeneity artifact associated with the wave behavior (RF passive shimming) or to locally enhance the signal-to-noise ratio (SNR) in targeted regions of interest (ROIs; RF field focusing). (c) 2006 Wiley-Liss, Inc.

  17. A comparison of intensity modulated x-ray therapy to intensity modulated proton therapy for the delivery of non-uniform dose distributions

    NASA Astrophysics Data System (ADS)

    Flynn, Ryan

    2007-12-01

    The distribution of biological characteristics such as clonogen density, proliferation, and hypoxia throughout tumors is generally non-uniform, therefore it follows that the optimal dose prescriptions should also be non-uniform and tumor-specific. Advances in intensity modulated x-ray therapy (IMXT) technology have made the delivery of custom-made non-uniform dose distributions possible in practice. Intensity modulated proton therapy (IMPT) has the potential to deliver non-uniform dose distributions as well, while significantly reducing normal tissue and organ at risk dose relative to IMXT. In this work, a specialized treatment planning system was developed for the purpose of optimizing and comparing biologically based IMXT and IMPT plans. The IMXT systems of step-and-shoot (IMXT-SAS) and helical tomotherapy (IMXT-HT) and the IMPT systems of intensity modulated spot scanning (IMPT-SS) and distal gradient tracking (IMPT-DGT), were simulated. A thorough phantom study was conducted in which several subvolumes, which were contained within a base tumor region, were boosted or avoided with IMXT and IMPT. Different boosting situations were simulated by varying the size, proximity, and the doses prescribed to the subvolumes, and the size of the phantom. IMXT and IMPT were also compared for a whole brain radiation therapy (WBRT) case, in which a brain metastasis was simultaneously boosted and the hippocampus was avoided. Finally, IMXT and IMPT dose distributions were compared for the case of non-uniform dose prescription in a head and neck cancer patient that was based on PET imaging with the Cu(II)-diacetyl-bis(N4-methylthiosemicarbazone (Cu-ATSM) hypoxia marker. The non-uniform dose distributions within the tumor region were comparable for IMXT and IMPT. IMPT, however, was capable of delivering the same non-uniform dose distributions within a tumor using a 180° arc as for a full 360° rotation, which resulted in the reduction of normal tissue integral dose by a factor of

  18. Stonefly (Plecoptera) Feeding Modes: Variation Along a California River Continuum

    Treesearch

    Richard L. Bottorff; Allen W. Knight

    1989-01-01

    The distribution of Plecoptera along a California river was used to test several predictions of the River Continuum Concept about how functional feeding groups should change along a stream's length. Stoneflies were collected from stream orders 1-6 (123 km) of the Cosumnes River continuum in the central Sierra Nevada. The 69 stonefly species collected were...

  19. Impact of Urbanization on Precipitation Distribution and Intensity over Lake Victoria Basin

    NASA Astrophysics Data System (ADS)

    Gudoshava, M.; Semazzi, F. H. M.

    2014-12-01

    In this study, sensitivity simulations on the impact of rapid urbanization over Lake Victoria Basin in East Africa were done using a Regional Climate Model (RegCM4.4-rc29) with the Hostetler lake model activated. The simulations were done for the rainy seasons that is the long rains (March-April-May) and short rains (October-November-December). Africa is projected to have a surge in urbanization with an approximate rate of 590% in 2030 over their 2000 levels. The Northern part of Lake Victoria Basin and some parts of Rwanda and Burundi are amongst the regions with high urbanization projections. Simulations were done with the land cover for 2000 and the projected 2030 urbanization levels. The results showed that increasing the urban fraction over the northern part of the basin modified the physical parameters such as albedo, moisture and surface energy fluxes, aerodynamic roughness and surface emissivity, thereby altering the precipitation distribution, intensity and frequency in the region. The change in the physical parameters gave a response of an average increase in temperature of approximately 2oC over the urbanized region. A strong convergence zone was formed over the urbanized region and thereby accelerating the lake-breeze front towards the urbanized region center. Precipitation in the urbanized region and regions immediate to the area increased by approximately 4mm/day, while drying up the southern (non-urbanized) side of the basin. The drying up of the southern side of the basin could be a result of divergent flow and subsidence that suppresses vertical development of storms.

  20. Rapid post-earthquake modelling of coseismic landslide intensity and distribution for emergency response decision support

    NASA Astrophysics Data System (ADS)

    Robinson, Tom R.; Rosser, Nicholas J.; Densmore, Alexander L.; Williams, Jack G.; Kincey, Mark E.; Benjamin, Jessica; Bell, Heather J. A.

    2017-09-01

    Current methods to identify coseismic landslides immediately after an earthquake using optical imagery are too slow to effectively inform emergency response activities. Issues with cloud cover, data collection and processing, and manual landslide identification mean even the most rapid mapping exercises are often incomplete when the emergency response ends. In this study, we demonstrate how traditional empirical methods for modelling the total distribution and relative intensity (in terms of point density) of coseismic landsliding can be successfully undertaken in the hours and days immediately after an earthquake, allowing the results to effectively inform stakeholders during the response. The method uses fuzzy logic in a GIS (Geographic Information Systems) to quickly assess and identify the location-specific relationships between predisposing factors and landslide occurrence during the earthquake, based on small initial samples of identified landslides. We show that this approach can accurately model both the spatial pattern and the number density of landsliding from the event based on just several hundred mapped landslides, provided they have sufficiently wide spatial coverage, improving upon previous methods. This suggests that systematic high-fidelity mapping of landslides following an earthquake is not necessary for informing rapid modelling attempts. Instead, mapping should focus on rapid sampling from the entire affected area to generate results that can inform the modelling. This method is therefore suited to conditions in which imagery is affected by partial cloud cover or in which the total number of landslides is so large that mapping requires significant time to complete. The method therefore has the potential to provide a quick assessment of landslide hazard after an earthquake and may therefore inform emergency operations more effectively compared to current practice.

  1. Determination of Stress Intensity Factor Distributions for "Interface" Cracks in Incompressible, Dissimilar Materials

    NASA Technical Reports Server (NTRS)

    Smith, C. W.

    1997-01-01

    The present study was undertaken in order to develop test methods and procedures for measuring the variation of the stress intensity factor through the thickness in bimaterial specimens containing cracks within and parallel to the bond line using the frozen stress photoelastic method. Since stress freezing materials are incompressible above critical temperature, and since thick plates are to be employed which tend to produce a state of plane strain near the crack tip, the interface near tip fracture equations reduce to the classic form for homogeneous materials. Moreover, zero thickness interfaces do not exist when materials are bonded together. It was decided early on that it would be important to insure a uniform straight and accurate crack tip region through the thickness of the body to reduce scatter in the SIF distribution through the thickness. It was also observed that rubberlike materials which were desired to be modeled exhibited significant tip blunting prior to crack extension and that some blunting of the tip would provide a more realistic model. It should be noted that, in normal stress freezing photoelastic work, it is considered good practice to avoid utilizing data near bond lines in photoelastic models due to the bond line stresses which inevitably develop when two parts are bonded together. Thus, the present study involves certain exploratory aspects in deviating from standard practice in stress freezing work. With the above ideas in mind, several different test methods were investigated and are described in the following sections and appendices. The geometry selected for the program was a thick, edge cracked specimen containing a bond line.

  2. Distribution of congenital anomalies in a neonatal intensive care unit in Turkey.

    PubMed

    Dursun, Arzu; Zenciroglu, Ayşegul; Hakan, Nilay; Karadag, Nilgun; Karagol, Belma Saygili; Aydin, Banu; Dilli, Dilek; Okumus, Nurullah; Beken, Serdar

    2014-07-01

    Congenital anomalies are one of the important reasons of mortality and morbidity in newborns. The aim of this study is to determine the incidence, distribution and the mortality of the congenital anomalies in a single neonatal intensive care unit (NICU) from Turkey. A retrospective analysis was performed between 2005 and 2012 in NICU using a computerized database. Variables including the type of anomaly, antenatal and postnatal history, gestational age, birth weight, consanguinity and other demographic, clinical and related laboratory variables were extracted from the computerized database using ICD-10 codes. Congenital anomalies were classified according to involved organ systems and also classified as single and multiple anomalies. A total of 1024 newborns with congenital anomaly (CA) (13.7%) were identified among the 7450 hospitalized newborns in NICU. The most affected system was the cardiovascular system (68.8%). Most of the anomalies (67.1%) were single anomalies. Of all, 59.4% had single major, 7.7% had single minor, 9% had single major plus single minor, 18.4% had multiple major and 2% had multiple minor anomalies. On the other hand, 96.3, 1.9, 0.1 and 1.7% of the newborns had malformation, deformation, disruption and dysplasia, respectively. Chromosomal analysis was only performed 24.8% of the newborns with CA and among them, 65.3% of these were in normal limits. The most frequently detected chromosomal abnormality was trisomy 21. Overall, mortality rate was 15.5% among the newborns with CA. In conclusion, the most common and mortal CA was cardio-vascular malformations in our hospital. The overall prevalence of cardio-vascular malformations among the newborn was higher than previously reported studies in Turkey. Further, studies with larger sample size are needed to determine CA in Turkey.

  3. Resonator with a back deformable mirror for the formation of a beam with a given intensity distribution

    SciTech Connect

    Kiyko, V V; Kislov, V I; Ofitserov, Evgenii N

    2011-10-31

    We present the results of a numerical-analytical study of formation of an output beam with a given intensity distribution for a resonator with a back deformable mirror (DM) and semitransparent spherical front mirror. Using the theory of inverse optical problems in the diffraction approximation, the basic characteristics of a laser resonator with a DM are considered as functions of the reference resonator configuration and the form of the distribution function, describing the given intensity. The laser beam formation in the reference resonator with plane-parallel and concentric configurations is compared. In the investigated resonators, the given intensity distribution is a fundamental mode; the selectivity (determined by the power losses of transverse modes) of the resonator with a DM is comparable with that of the reference resonator. It is shown that the formation of the given intensity distributions (uniform, super-Gaussian, or having several maxima) requires a DM with the amplitude of deformations of the optical surface of the order of {lambda} and the number of control channels from 1 to nearly 10.

  4. Measurement of Acoustic Intensity Distribution and Radiation Power of Flat-Plate Phased-Array Sound Source

    NASA Astrophysics Data System (ADS)

    Yokoyama, Tomoki; Takahashi, Kumiko; Seki, Daizaburou; Hasegawa, Akio

    2002-05-01

    The acoustic intensity distribution and radiation power of a flat-plate phased-array sound source consisting of Tonpilz-type transducers were measured. This study shows that the active acoustic intensity is skewed in the direction of wave propagation. In addition, it clarifies that if the measurement is carried out in the immediate vicinity of the sound source, the reactive acoustic intensity distribution is effective for identifying the positions of the individual sound source elements. Experimental values of active radiation power agree well with theoretical values. Conversely, experimental values of reactive radiation power do not agree with theoretical values; it is clear that they fluctuate significantly with distance from the radiating surface. The reason for this is explained in the case of a point sound source.

  5. Evolution dynamics of charge state distribution in neon interaction with x-ray pulses of variant intensities and durations

    NASA Astrophysics Data System (ADS)

    Gao, Cheng; Zeng, Jiaolong; Yuan, Jianmin

    2015-03-01

    The level population and charge state distribution (CSD) of the neon atomic system interacting with x-ray pulses of variant intensities and durations at a central photon energy of 1110 eV are investigated by solving the time-dependent rate equations. The laser beam has a circular spot size with a Gaussian intensity pattern and the time history of the intensity is represented by Gaussian distribution in time. As an example, the CSD as a function of time is given at different distances from the spot center for an x-ray beam of intensity 1.5 × 1017 W/cm2 and duration 75 fs (fs) for a spot size of 1 μm (full width at half maximum). The final CSD after averaging over the space and time is compared with a recent experiment and good agreement is found between the theory and experiment. Then systematic investigations are carried out to study the evolution of CSD with a wide range of intensity from 1.0 × 1015 W/cm2 to 1.0 × 1019 W/cm2 and duration from 30 fs to 100 fs. The results show that at intensities lower than 1.0 × 1015 W/cm2, the CSD shows a typical physical picture of weak x-ray photoionization of the neutral atomic neon. At higher intensity, i.e., larger than 5.0 × 1016 W/cm2, the dominant ionization stages are Ne7+ and Ne8+, while the fractions of ions in the Ne3+-Ne6+ stages are low for all laser durations and intensities.

  6. Isostaticity in Cosserat Continuum

    DTIC Science & Technology

    2012-01-01

    Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 15. SUBJECT TERMS Isostaticity, Cosserat, Granular, Force chains Antoinette ...TELEPHONE NUMBER Antoinette Tordesillas 038-344-9685 3. DATES COVERED (From - To) Standard Form 298 (Rev 8/98) Prescribed by ANSI Std. Z39.18...Cosserat continuum Antoinette Tordesillas · Jingyu Shi · John F. Peters Received: 29 August 2011 / Published online: 16 March 2012 © Springer-Verlag 2012

  7. Solar radio continuum storms

    NASA Technical Reports Server (NTRS)

    Sakurai, K.

    1976-01-01

    The paper reviews the current status of research on solar radio continuum emissions from metric to hectometric wave frequencies, emphasizing the role of energetic electrons in the 10-100 keV range in these emissions. It is seen that keV-energy electrons generated in active sunspot groups must be the sources of radio continuum storm emissions for wide frequency bands. These electrons excite plasma oscillations in the medium, which in turn are converted to electromagnetic radiation. The radio noise continuum sources are usually associated with type III burst activity observed above these sources. Although the mechanism for the release of the energetic electrons is not known, it seems they are ejected from storm source regions in association with rapid variation of associated sunspot magnetic fields due to their growth into complex types. To explain some of the observed characteristics, the importance of two-stream instability and the scattering of ambient plasma ions on energetic electron streams is pointed out.

  8. Sociospatial distribution of access to facilities for moderate and vigorous intensity physical activity in Scotland by different modes of transport

    PubMed Central

    2012-01-01

    Background People living in neighbourhoods of lower socioeconomic status have been shown to have higher rates of obesity and a lower likelihood of meeting physical activity recommendations than their more affluent counterparts. This study examines the sociospatial distribution of access to facilities for moderate or vigorous intensity physical activity in Scotland and whether such access differs by the mode of transport available and by Urban Rural Classification. Methods A database of all fixed physical activity facilities was obtained from the national agency for sport in Scotland. Facilities were categorised into light, moderate and vigorous intensity activity groupings before being mapped. Transport networks were created to assess the number of each type of facility accessible from the population weighted centroid of each small area in Scotland on foot, by bicycle, by car and by bus. Multilevel modelling was used to investigate the distribution of the number of accessible facilities by small area deprivation within urban, small town and rural areas separately, adjusting for population size and local authority. Results Prior to adjustment for Urban Rural Classification and local authority, the median number of accessible facilities for moderate or vigorous intensity activity increased with increasing deprivation from the most affluent or second most affluent quintile to the most deprived for all modes of transport. However, after adjustment, the modelling results suggest that those in more affluent areas have significantly higher access to moderate and vigorous intensity facilities by car than those living in more deprived areas. Conclusions The sociospatial distributions of access to facilities for both moderate intensity and vigorous intensity physical activity were similar. However, the results suggest that those living in the most affluent neighbourhoods have poorer access to facilities of either type that can be reached on foot, by bicycle or by bus than

  9. Measurement of the entry-spin distribution imparted to the high excitation continuum region of gadolinium nuclei via (p,d) and (p,t) reactions

    NASA Astrophysics Data System (ADS)

    Ross, T. J.; Beausang, C. W.; Hughes, R. O.; Allmond, J. M.; Angell, C. T.; Basunia, M. S.; Bleuel, D. L.; Burke, J. T.; Casperson, R. J.; Escher, J. E.; Fallon, P.; Hatarik, R.; Munson, J.; Paschalis, S.; Petri, M.; Phair, L.; Ressler, J. J.; Scielzo, N. D.; Thompson, I. J.

    2012-05-01

    Over the last several years, the surrogate reaction technique has been successfully employed to extract (n,f) and (n,γ) cross sections in the actinide region to a precision of ˜5% and ˜20%, respectively. However, attempts to apply the technique in the rare earth region have shown large (factors of 2-3) discrepancies between the directly measured (n,γ) and extracted surrogate cross sections. One possible origin of this discrepancy lies in differences between the initial spin-parity population distribution in the neutron induced and surrogate reactions. To address this issue, the angular momentum transfer to the high excitation energy quasicontinuum region in Gd nuclei has been investigated. The (p,d) and (p,t) reactions on 154,158Gd at a beam energy of 25 MeV were utilized. Assuming a single dominant angular momentum transfer component, the measured angular distribution for the (p,d) reactions is well reproduced by distorted-wave Born approximation (DWBA) calculations for ΔL=4 ℏ transfer, whereas the (p,t) reactions are better characterized by ΔL=5 ℏ. A linear combination of DWBA calculations, weighted according to a distribution of L transfers (peaking around ΔL=4-5 ℏ), is in excellent agreement with the experimental angular distributions.

  10. A Scheduling Algorithm for the Distributed Student Registration System in Transaction-Intensive Environment

    ERIC Educational Resources Information Center

    Li, Wenhao

    2011-01-01

    Distributed workflow technology has been widely used in modern education and e-business systems. Distributed web applications have shown cross-domain and cooperative characteristics to meet the need of current distributed workflow applications. In this paper, the author proposes a dynamic and adaptive scheduling algorithm PCSA (Pre-Calculated…

  11. A Scheduling Algorithm for the Distributed Student Registration System in Transaction-Intensive Environment

    ERIC Educational Resources Information Center

    Li, Wenhao

    2011-01-01

    Distributed workflow technology has been widely used in modern education and e-business systems. Distributed web applications have shown cross-domain and cooperative characteristics to meet the need of current distributed workflow applications. In this paper, the author proposes a dynamic and adaptive scheduling algorithm PCSA (Pre-Calculated…

  12. Continuum Nuclear Structure via

    NASA Astrophysics Data System (ADS)

    Templon, Jeffrey A.

    1993-01-01

    Nuclear spectra are generally well-understood for excitation energies below the particle-emission threshold. Above this threshold, excited states decay preferentially by emission of nucleons or nucleon clusters. These resonant excitations are short-lived, producing continuum spectra of overlapping states accompanied by non-resonant, probe -dependent background processes. The resonant excitations' properties are difficult to deduce from these spectra. Many important advances in nuclear physics require understanding of such excitations. (e,e^' X) coincidence experiments have established the utility of angular correlation measurements of particle (X) emitted by decaying resonances for continuum studies. However, electron-induced reactions excite only a subset of the total nuclear response. Hadronic probes are necessary for a complete study. This dissertation describes a (p,p^' X) coincidence experiment, the first at intermediate energies where microscopic theories apply. The reaction's utility was investigated and applied to ^{12 }C. The experiment was performed using a 156 MeV polarized proton beam. A magnetic spectrometer was used to detect scattered protons. An array of eight silicon-detector telescopes was constructed and used to measure the angular correlation of charged particles (X). Inclusive (p,p ^') and exclusive (p,p ^' X) data were acquired simultaneously. The momentum transfer range (0.6<= q<= 1.2 fm^{-1}) was covered in three spectrometer angle settings. The excitation energy range spanned the region from sharp states to quasifree processes. Analyzing powers and cross sections were measured for both inclusive and exclusive data. A simple reaction model was developed which suggested a Legendre-polynomial series should describe the sigma(theta_{X}) data. The model relates the polynomial coefficients to nuclear structure information. A result of this work is that this series was found to satisfactorily describe the data and provided new information about

  13. Studies on light intensity distribution inside an open pond photo-bioreactor.

    PubMed

    Pandey, Ramakant; Sahu, Akhilesh; K K, Vasumathi; M, Premalatha

    2015-08-01

    Light intensity profiles inside an open tank were studied using ANSYS Fluent. Experiments were performed by taking Scenedesmus arcuatus, green microalgae at three different concentrations under actual sunlight conditions. Absorption of light intensity at different depths was measured experimentally. The results generated from CFD simulations were compared with the experimental results and the cornet model. It has been found that there is a good agreement between the light intensity profile obtained from the CFD simulation and that calculated using the Cornet's model. Light intensity profiles at different depths were calculated using CFD simulation by varying the dimensions of the tank. The effect of wall reflectivity, diffuse fraction and scattering phase function on light profile in side open tank are also studied using CFD simulation.

  14. Generalized Kapchinskij-Vladimirskij Distribution and Envelope Equation for High-intensity Beams in a Coupled Transverse Focusing Lattice

    SciTech Connect

    Hong Qin, Moses Chung, and Ronald C. Davidson

    2009-11-20

    In an uncoupled lattice, the Kapchinskij-Vladimirskij (KV) distribution function first analyzed in 1959 is the only known exact solution of the nonlinear Vlasov-Maxwell equations for high- intensity beams including self-fields in a self-consistent manner. The KV solution is generalized here to high-intensity beams in a coupled transverse lattice using the recently developed generalized Courant-Snyder invariant for coupled transverse dynamics. This solution projects to a rotating, pulsating elliptical beam in transverse configuration space, determined by the generalized matrix envelope equation.

  15. Intensity distribution and isoseismal maps for the Nisqually, Washington, earthquake of 28 February 2001

    USGS Publications Warehouse

    Dewey, James W.; Hopper, Margaret G.; Wald, David J.; Quitoriano, Vincent; Adams, Elizabeth R.

    2002-01-01

    We present isoseismal maps, macroseismic intensities, and community summaries of damage for the MW=6.8 Nisqually, Washington, earthquake of 28 February, 2001. For many communities, two types of macroseismic intensity are assigned, the traditional U.S. Geological Survey Modified Mercalli Intensities (USGS MMI) and a type of intensity newly introduced with this paper, the USGS Reviewed Community Internet Intensity (RCII). For most communities, the RCII is a reviewed version of the Community Internet Intensity (CII) of Wald and others (1999). For some communities, RCII is assigned from such non-CII sources as press reports, engineering reports, and field reconnaissance observations. We summarize differences between procedures used to assign RCII and USGS MMI, and we show that the two types of intensity are nonetheless very similar for the Nisqually earthquake. We do not see evidence for systematic differences between RCII and USGS MMI that would approach one intensity unit, at any level of shaking, but we document a tendency for the RCII to be slightly lower than MMI in regions of low intensity and slightly higher than MMI in regions of high intensity. The highest RCII calculated for the Nisqually earthquake is 7.6, calculated for zip code 98134, which includes the ?south of downtown? (Sodo) area of Seattle and Harbor Island. By comparison, we assigned a traditional USGS MMI 8 to the Sodo area of Seattle. In all, RCII of 6.5 and higher were assigned to 58 zip-code regions. At the lowest intensities, the Nisqually earthquake was felt over an area of approximately 350,000 square km (approximately 135,000 square miles) in Washington, Oregon, Idaho, Montana, and southern British Columbia, Canada. On the basis of macroseismic effects, we infer that shaking in the southern Puget Sound region was somewhat less for the 2001 Nisqually earthquake than for the Puget Sound earthquake of April 13, 1949, which had nearly the same hypocenter and magnitude. Allowing for differences

  16. Solar radio continuum storms and a breathing magnetic field model

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Radio noise continuum emissions observed in metric and decametric wave frequencies are, in general, associated with actively varying sunspot groups accompanied by the S-component of microwave radio emissions. These continuum emission sources, often called type I storm sources, are often associated with type III burst storm activity from metric to hectometric wave frequencies. This storm activity is, therefore, closely connected with the development of these continuum emission sources. It is shown that the S-component emission in microwave frequencies generally precedes, by several days, the emission of these noise continuum storms of lower frequencies. In order for these storms to develop, the growth of sunspot groups into complex types is very important in addition to the increase of the average magnetic field intensity and area of these groups. After giving a review on the theory of these noise continuum storm emissions, a model is briefly considered to explain the relation of the emissions to the storms.

  17. The thermal infrared continuum in solar flares

    NASA Astrophysics Data System (ADS)

    Fletcher, Lyndsay; Simoes, Paulo; Kerr, Graham Stewart; Hudson, Hugh S.; Gimenez de Castro, C. Guillermo; Penn, Matthew J.

    2017-08-01

    Observations of the Sun with the Atacama Large Millimeter Array have now started, and the thermal infrared will regularly be accessible from the NSF’s Daniel K. Inouye Solar Telescope. Motivated by the prospect of these new observations, and by recent flare detections in the mid infrared, we set out here to model and understand the source of the infrared continuum in flares, and to explore its diagnostic capability for the physical conditions in the flare atmosphere. We use the 1D radiation hydrodynamics code RADYN to calculate mid-infrared continuum emission from model atmospheres undergoing sudden deposition of energy by non-thermal electrons. We identify and characterise the main continuum thermal emission processes relevant to flare intensity enhancement in the mid- to far-infrared (2-200 micron) spectral range as free-free emission on neutrals and ions. We find that the infrared intensity evolution tracks the energy input to within a second, albeit with a lingering intensity enhancement, and provides a very direct indication of the evolution of the atmospheric ionization. The prediction of highly impulsive emission means that, on these timescales, the atmospheric hydrodynamics need not be considered in analysing the mid-IR signatures.

  18. Unexpected spatial intensity distributions and onset timing of solar electron events observed by closely spaced STEREO spacecraft

    NASA Astrophysics Data System (ADS)

    Klassen, A.; Dresing, N.; Gómez-Herrero, R.; Heber, B.; Müller-Mellin, R.

    2016-09-01

    We present multi-spacecraft observations of four solar electron events using measurements from the Solar Electron Proton Telescope (SEPT) and the Electron Proton Helium INstrument (EPHIN) on board the STEREO and SOHO spacecraft, respectively, occurring between 11 October 2013 and 1 August 2014, during the approaching superior conjunction period of the two STEREO spacecraft. At this time the longitudinal separation angle between STEREO-A (STA) and STEREO-B (STB) was less than 72°. The parent particle sources (flares) of the four investigated events were situated close to, in between, or to the west of the STEREO's magnetic footpoints. The STEREO measurements revealed a strong difference in electron peak intensities (factor ≤12) showing unexpected intensity distributions at 1 AU, although the two spacecraft had nominally nearly the same angular magnetic footpoint separation from the flaring active region (AR) or their magnetic footpoints were both situated eastwards from the parent particle source. Furthermore, the events detected by the two STEREO imply a strongly unexpected onset timing with respect to each other: the spacecraft magnetically best connected to the flare detected a later arrival of electrons than the other one. This leads us to suggest the concept of a rippled peak intensity distribution at 1 AU formed by narrow peaks (fingers) superposed on a quasi-uniform Gaussian distribution. Additionally, two of the four investigated solar energetic particle (SEP) events show a so-called circumsolar distribution and their characteristics make it plausible to suggest a two-component particle injection scenario forming an unusual, non-uniform intensity distribution at 1 AU.

  19. Conductivity of continuum percolating systems

    NASA Astrophysics Data System (ADS)

    Stenull, Olaf; Janssen, Hans-Karl

    2001-11-01

    We study the conductivity of a class of disordered continuum systems represented by the Swiss-cheese model, where the conducting medium is the space between randomly placed spherical holes, near the percolation threshold. This model can be mapped onto a bond percolation model where the conductance σ of randomly occupied bonds is drawn from a probability distribution of the form σ-a. Employing the methods of renormalized field theory we show to arbitrary order in ɛ expansion that the critical conductivity exponent of the Swiss-cheese model is given by tSC(a)=(d-2)ν+max[φ,(1-a)-1], where d is the spatial dimension and ν and φ denote the critical exponents for the percolation correlation length and resistance, respectively. Our result confirms a conjecture that is based on the ``nodes, links, and blobs'' picture of percolation clusters.

  20. Inlet turbulence intensity level and cross-stream distribution effects on the heat transfer in plane wall jets

    NASA Technical Reports Server (NTRS)

    Adeniji-Fashola, A. A.

    1989-01-01

    The effect of the turbulence intensity level and its cross-stream distribution at the inlet on the numerical prediction of the heat transfer in a two-dimensional turbulent-wall jet was investigated. The investigation was carried out within the framework of the standard kappa-epsilon turbulence model. The predicted Nusselt number showed the influence of the turbulence intensity level and its cross-stream distribution at the inlet to be significant but restricted to the first 15 slot widths from the inlet slot. Beyond this location, all the predictions were observed to collapse onto a single curve which exhibited a maximum over-prediction of about 30 percent when compared with the available experimental data.

  1. Quantum-mechanical calculation of the intensity distribution in Raman and resonance Raman spectra of a phenylalanine aqueous solution

    NASA Astrophysics Data System (ADS)

    Burova, T. G.; Shcherbakov, R. S.

    2017-03-01

    Quantum-mechanical calculations of the intensity distribution in the resonance Raman spectrum of an aqueous solution of phenylalanine, excited by light with wavelengths of 193, 204, 218, and 235 nm, and in the nonresonant Raman spectrum excited at a wavelength of 488 nm have been performed. The calculation results are in satisfactory agreement with the experimental data in the literature. Spectral lines characteristic of phenylalanine are observed, which can be used as markers when analyzing the peptide structure. It is noted that the contribution of highly excited electronic states (spaced by less than 10 eV from the resonant lines) to the scattering tensor components must be taken into account. The important role of the Herzberg-Teller effect in the description of spectral intensity distribution is demonstrated.

  2. Enhancing a Distributed Rainfall Intensity for Flood Analysis within a GIS Framework in an Urban Area (Kajang Flood)

    NASA Astrophysics Data System (ADS)

    Salleh, S. H. M.; Sidek, L. M.

    2016-03-01

    The town of Kajang has experienced major flood events in previous decades since 1970s. Due to Eastern and Western Monsoon seasons in Malaysia, Kajang has potential to face with number of flood events. One of the critical elements in flood analysis is rainfall distribution. Therefore, flood studies need to have an optimum cognition of rainfall distribution as main input. In this study, HEC GeoHMS model was used in GIS (Geographic Information System) for Sungai Jeluh catchment (Kajang) due to estimation (visualization) of distributed rainfall in Kajang. In comparison with conventional methods, which they produced rainfall in lumped mode (e.g. Thiessen’s polygon), HEC GeoHMS visualized and tabulate a full distribution of rainfall for each small part (pixel of map) in a case study. HEC GeoHMS model for Sungai Jeluh has been set up by feeding high resolution of spatial and temporal resolution data (precipitation). Result of this study shows that rainfall by high intensity is distributed near urban area (downtown) in comparison with upstream which involved with less rainfall intensity.

  3. Nebular Continuum and Line Emission in Stellar Population Synthesis Models

    NASA Astrophysics Data System (ADS)

    Byler, Nell; Dalcanton, Julianne J.; Conroy, Charlie; Johnson, Benjamin D.

    2017-05-01

    Accounting for nebular emission when modeling galaxy spectral energy distributions (SEDs) is important, as both line and continuum emissions can contribute significantly to the total observed flux. In this work, we present a new nebular emission model integrated within the Flexible Stellar Population Synthesis code that computes the line and continuum emission for complex stellar populations using the photoionization code Cloudy. The self-consistent coupling of the nebular emission to the matched ionizing spectrum produces emission line intensities that correctly scale with the stellar population as a function of age and metallicity. This more complete model of galaxy SEDs will improve estimates of global gas properties derived with diagnostic diagrams, star formation rates based on Hα, and physical properties derived from broadband photometry. Our models agree well with results from other photoionization models and are able to reproduce observed emission from H ii regions and star-forming galaxies. Our models show improved agreement with the observed H ii regions in the Ne iii/O ii plane and show satisfactory agreement with He ii emission from z = 2 galaxies, when including rotating stellar models. Models including post-asymptotic giant branch stars are able to reproduce line ratios consistent with low-ionization emission regions. The models are integrated into current versions of FSPS and include self-consistent nebular emission predictions for MIST and Padova+Geneva evolutionary tracks.

  4. Laser light scattering in turbid media Part I: Experimental and simulated results for the spatial intensity distribution.

    PubMed

    Berrocal, Edouard; Sedarsky, David L; Paciaroni, Megan E; Meglinski, Igor V; Linne, Mark A

    2007-08-20

    We investigate the scattering and multiple scattering of a typical laser beam (lambda = 800 nm) in the intermediate scattering regime. The turbid media used in this work are homogeneous solutions of monodisperse polystyrene spheres in distilled water. The two-dimensional distribution of light intensity is recorded experimentally, and calculated via Monte Carlo simulation for both forward and side scattering. The contribution of each scattering order to the total detected light intensity is quantified for a range of different scattering phase functions, optical depths, and detection acceptance angles. The Lorentz-Mie scattering phase function for individual particles is varied by using different sphere diameters (D = 1 and 5 mum). The optical depth of the turbid medium is varied (OD = 2, 5, and 10) by employing different concentrations of polystyrene spheres. Detection angles of theta(a) = 1.5 degrees and 8.5 degrees are considered. A novel approach which realistically models the experimental laser source is employed in this paper, and very good agreement between the experimental and simulated results is demonstrated. The data presented here can be of use to validate any other modern Monte Carlo models which generate spatially resolved light intensity distributions. Finally, an effective correction procedure to the Beer-Lambert law is proposed based on the Monte Carlo calculation of the ballistic photon contribution to the total detected light intensity.

  5. The Response Continuum

    SciTech Connect

    Caltagirone, Sergio; Frincke, Deborah A.

    2005-06-17

    Active response is a sequence of actions per- formed speci¯cally to mitigate a detected threat. Response decisions always follow detection: a decision to take `no ac- tion' remains a response decision. However, active response is a complex subject that has received insu±cient formal attention. To facilitate discussion, this paper provides a framework that proposes a common de¯nition, describes the role of response and the major issues surrounding response choices, and ¯nally, provides a model for the process of re- sponse. This provides a common starting point for discus- sion of the full response continuum as an integral part of contemporary computer security.

  6. Numerical simulations of the hard X-ray pulse intensity distribution at the Linac Coherent Light Source

    DOE PAGES

    Pardini, Tom; Aquila, Andrew; Boutet, Sebastien; ...

    2017-06-15

    Numerical simulations of the current and future pulse intensity distributions at selected locations along the Far Experimental Hall, the hard X-ray section of the Linac Coherent Light Source (LCLS), are provided. Estimates are given for the pulse fluence, energy and size in and out of focus, taking into account effects due to the experimentally measured divergence of the X-ray beam, and measured figure errors of all X-ray optics in the beam path. Out-of-focus results are validated by comparison with experimental data. Previous work is expanded on, providing quantitatively correct predictions of the pulse intensity distribution. Numerical estimates in focus aremore » particularly important given that the latter cannot be measured with direct imaging techniques due to detector damage. Finally, novel numerical estimates of improvements to the pulse intensity distribution expected as part of the on-going upgrade of the LCLS X-ray transport system are provided. As a result, we suggest how the new generation of X-ray optics to be installed would outperform the old one, satisfying the tight requirements imposed by X-ray free-electron laser facilities.« less

  7. Numerical simulations of the hard X-ray pulse intensity distribution at the Linac Coherent Light Source.

    PubMed

    Pardini, Tom; Aquila, Andrew; Boutet, Sébastien; Cocco, Daniele; Hau-Riege, Stefan P

    2017-07-01

    Numerical simulations of the current and future pulse intensity distributions at selected locations along the Far Experimental Hall, the hard X-ray section of the Linac Coherent Light Source (LCLS), are provided. Estimates are given for the pulse fluence, energy and size in and out of focus, taking into account effects due to the experimentally measured divergence of the X-ray beam, and measured figure errors of all X-ray optics in the beam path. Out-of-focus results are validated by comparison with experimental data. Previous work is expanded on, providing quantitatively correct predictions of the pulse intensity distribution. Numerical estimates in focus are particularly important given that the latter cannot be measured with direct imaging techniques due to detector damage. Finally, novel numerical estimates of improvements to the pulse intensity distribution expected as part of the on-going upgrade of the LCLS X-ray transport system are provided. We suggest how the new generation of X-ray optics to be installed would outperform the old one, satisfying the tight requirements imposed by X-ray free-electron laser facilities.

  8. Inferring local competition intensity from patch size distributions: a test using biological soil crusts

    USGS Publications Warehouse

    Bowker, Matthew A.; Maestre, Fernando T.

    2012-01-01

    Dryland vegetation is inherently patchy. This patchiness goes on to impact ecology, hydrology, and biogeochemistry. Recently, researchers have proposed that dryland vegetation patch sizes follow a power law which is due to local plant facilitation. It is unknown what patch size distribution prevails when competition predominates over facilitation, or if such a pattern could be used to detect competition. We investigated this question in an alternative vegetation type, mosses and lichens of biological soil crusts, which exhibit a smaller scale patch-interpatch configuration. This micro-vegetation is characterized by competition for space. We proposed that multiplicative effects of genetics, environment and competition should result in a log-normal patch size distribution. When testing the prevalence of log-normal versus power law patch size distributions, we found that the log-normal was the better distribution in 53% of cases and a reasonable fit in 83%. In contrast, the power law was better in 39% of cases, and in 8% of instances both distributions fit equally well. We further hypothesized that the log-normal distribution parameters would be predictably influenced by competition strength. There was qualitative agreement between one of the distribution's parameters (μ) and a novel intransitive (lacking a 'best' competitor) competition index, suggesting that as intransitivity increases, patch sizes decrease. The correlation of μ with other competition indicators based on spatial segregation of species (the C-score) depended on aridity. In less arid sites, μ was negatively correlated with the C-score (suggesting smaller patches under stronger competition), while positive correlations (suggesting larger patches under stronger competition) were observed at more arid sites. We propose that this is due to an increasing prevalence of competition transitivity as aridity increases. These findings broaden the emerging theory surrounding dryland patch size distributions

  9. Impact of the accurateness of bidirectional reflectance distribution function data on the intensity and luminance distributions of a light-emitting diode mixing chamber as obtained by simulations

    NASA Astrophysics Data System (ADS)

    Audenaert, Jan; Leloup, Frédéric B.; Van Giel, Bart; Durinck, Guy; Deconinck, Geert; Hanselaer, Peter

    2013-09-01

    The reliability of ray tracing simulations is strongly dependent on the accuracy of the input data such as the bidirectional reflectance distribution function (BRDF). Software developers offer the possibility to implement BRDF data in different ways, ranging from simple predefined functions to detailed tabulated data. The impact of the accuracy of the implemented reflectance model on ray tracing simulations has been investigated. A light-emitting diode device including a frequently employed diffuse reflector [microcellular polyethylene terephthalate (MCPET)] was constructed. The luminous intensity distribution (LID) and luminance distribution from a specific viewpoint were measured with a near-field goniophotometer. Both distributions were also simulated by use of ray tracing software. Three different reflection models of MCPET were introduced, varying in complexity: a diffuse model, a diffuse/specular model, and a model containing tabulated BRDF data. A good agreement between the measured and simulated LID was found irrespective of the applied model. However, the luminance distributions only corresponded when the most accurate BRDF model was applied. This proves that even for diffuse reflective materials, a simple BRDF model may only be employed for simulations of the LID; for evaluation of luminance distributions, more complex models are needed.

  10. Intensity and degree of segregation in bimodal and multimodal grain size distributions

    NASA Astrophysics Data System (ADS)

    Katra, Itzhak; Yizhaq, Hezi

    2017-08-01

    The commonly used grain size analysis technique which applies moments (sorting, skewness and kurtosis) is less useful in the case of sediments with bimodal size distributions. Herein we suggest a new simple method for analyzing the degree of grain size segregation in sand-sized sediment that has clear bimodal size distributions. Two main features are used to characterize the bimodal distribution: grain diameter segregation, which is the normalized difference between coarse and fine grain diameters, and the frequency segregation which is the normalized difference in frequencies between two modes. The new defined indices can be calculated from frequency plot curves and can be graphically represented on a two dimensional coordinate system showing the dynamical aspects of the size distribution. The results enable comparison between granular samples from different locations and/or times to shed new light on the dynamic processes involved in grain size segregation of sediments. We demonstrate here the use of this method to analyze bimodal distributions of aeolian granular samples mostly from aeolian megaripples. Six different aeolian cases were analyzed to highlight the method's applicability, which is relevant to wide research themes in the Earth and environmental sciences, and can furthermore be easily adapted to analyze polymodal grain size distributions.

  11. Initial assessment of the intensity distribution of the 2011 Mw5.8 Mineral, Virginia, earthquake

    USGS Publications Warehouse

    Hough, Susan E.

    2012-01-01

    The intensity data collected by the U.S. Geological Survey (USGS) "Did You Feel It?" (DYFI) Website (USGS, DYFI; http://earthquake.usgs.gov/earthquakes/dyfi/events/se/082311a/us/index.html, last accessed Sept 2011) for the Mw5.8 Mineral, Virginia, earthquake, are unprecedented in their spatial richness and geographical extent. More than 133,000 responses were received during the first week following the earthquake. Although intensity data have traditionally been regarded as imprecise and generally suspect (e.g., Hough 2000), there is a growing appreciation for the potential utility of spatially rich, systematically determined DYFI data to address key questions in earthquake ground-motions science (Atkinson and Wald, 2007; Hauksson et al., 2008).

  12. Disorder fingerprint: Intensity distributions in the near field of random media

    NASA Astrophysics Data System (ADS)

    Naraghi, R. Rezvani; Sukhov, S.; Dogariu, A.

    2016-11-01

    The structural morphology of complex dielectric media determines their functionalities by driving the statistical properties of the electromagnetic fields. Our controlled experiments and full electromagnetic calculations that go beyond common dipolar approximations demonstrate that the specific characteristics of disorder lead to non-Rayleigh statistics of detected intensity, which can be directly accessed in the near field of random media and can be unambiguously related to the short-range correlations of disorder.

  13. Continuum Statistics of the Airy2 Process

    NASA Astrophysics Data System (ADS)

    Corwin, Ivan; Quastel, Jeremy; Remenik, Daniel

    2013-01-01

    We develop an exact determinantal formula for the probability that the Airy_2 process is bounded by a function g on a finite interval. As an application, we provide a direct proof that {sup({A}2(x)-x^2)} is distributed as a GOE random variable. Both the continuum formula and the GOE result have applications in the study of the end point of an unconstrained directed polymer in a disordered environment. We explain Johansson's (Commun. Math. Phys. 242(1-2):277-329, 2003) observation that the GOE result follows from this polymer interpretation and exact results within that field. In a companion paper (Moreno Flores et al. in Commun. Math. Phys. 2012) these continuum statistics are used to compute the distribution of the endpoint of directed polymers.

  14. Models of Uranium continuum radio emission

    NASA Technical Reports Server (NTRS)

    Romig, Joseph H.; Evans, David R.; Sawyer, Constance B.; Schweitzer, Andrea E.; Warwick, James W.

    1987-01-01

    Uranium continuum radio emission detected by the Voyager 2 Planetary Radio Astronomy experiment during the January 1986 encounter is considered. The continuum emissions comprised four components (equatorial emissions, anomaly emissions, strong nightside emissions, and weak nightside emissions) associated with different sources. The equatorial emissions appeared most prominently during the days before closest approach and extended from 40 kHz or below to about 120 kHz. The anomaly emissions were seen about 12 hours before closest approach and extended to about 250 kHz. The agreement found between Miranda's phase and strong radio emission at 20.4 kHz, just after closest approach, suggests intense dynamic activity on the Miranda L shell.

  15. Nonlinear-resonance line shapes: Dependence on the transverse intensity distribution of a light beam

    SciTech Connect

    Taichenachev, A.V.; Yudin, V.I.; Wynands, R.; Kitching, J.; Hollberg, L.

    2004-02-01

    We analyze the line shape and width of atomic coherent-population-trapping (CPT) resonances excited by laser beams with different transverse intensity profiles. A dramatic difference in the resonance line shape is found when comparing a beam with a 'steplike' profile to a beam with a Gaussian profile. In particular, for nonuniform profiles, a non-Lorentzian functional form is given that is more appropriate for describing the nonlinear resonance line shape than is a conventional Lorentzian. Our analysis is supported by measurements of CPT line shapes in a thermal vapor of {sup 85}Rb.

  16. Occurrence and distribution of livestock concentration areas on intensively managed pastures

    USDA-ARS?s Scientific Manuscript database

    Livestock frequently congregate at feeders, shades, or other sites on pastures creating point sources of nutrient runoff. Our objective was to determine the spatial distribution of soil nutrients in livestock concentration areas on pastures and quantify the relationships among the soil nutrient grad...

  17. Small mammal distributions relative to corridor edges within intensively managed southern pine plantations.

    Treesearch

    Nicole L. Constantine; Tyler A. Campbell; William M. Baughman; Timothy B. Harrington; Brian R. Chapman; Karl V. Miller

    2005-01-01

    We characterized small mammal communities in three loblolly pine (Pinus taeda) stands in the Lower Coastal Plain of South Carolina during June 1998-Aug. 2000 to investigate influence of corridor edges on small mammal distribution. We live-trapped small mammals in three regenerating stands following clearcutting. Harvested stands were bisected by...

  18. Modification of the velocity distribution of H(2) molecules in a supersonic beam by intense pulsed optical gradients.

    PubMed

    Ramirez-Serrano, Jaime; Strecker, Kevin E; Chandler, David W

    2006-07-07

    We report the acceleration and deceleration of H(2) molecules in a supersonic molecular beam by means of its interaction with an intense optical gradient from a nanosecond far-off-resonant optical pulse. The strong optical gradients are formed in the interference pattern of two intense optical pulses at 532 nm. The velocity distribution of the molecular beam, before and after the applied optical pulse, is measured by a velocity-mapped ion imaging technique. Changes in velocity up to 202 m s(-1)+/- 61 m s(-1) are observed in a molecular beam initially travelling at a mean speed of 563 m s(-1). We report the dependence of this change in velocity with the strength of the optical gradient applied.

  19. Classification of knowledge-intensive organizations

    NASA Astrophysics Data System (ADS)

    Marquart, Edward J.

    Managing knowledge workers in knowledge-intensive organizations has become important because knowledge itself is emerging as a primary sustainable competitive advantage. This dissertation traces the development of two important items related to knowledge-intensive organizations. First, it documents a careful study of the literature which allows for the construction of a Knowledge-Intensity Continuum. This continuum then forms the basis for the development of a Knowledge-Intensity Assessment survey instrument which allows an organization to be placed along this continuum. A cross-section of research, consulting, and manufacturing organizations was surveyed using this instrument. The findings provided evidence that supports the validity of the Knowledge-Intensity Continuum. Additionally, onsite interviews provided evidence that the Knowledge-Intensity Assessment survey can be used as a tool to locate any organization on this continuum. Using this survey to clearly identify knowledge-intensive organizations will allow for further research into effective management systems for knowledge workers in these organizations.

  20. Continuum Modeling of Facet Evolution

    NASA Astrophysics Data System (ADS)

    Kandel, Daniel

    2000-03-01

    Standard continuum models of surface dynamics are very useful for studying thin film evolution on the micron length scale. Unfortunately, they are inadequate below the roughening transition, since they do not appropriately describe faceting. Our goal is to propose a continuum approach which deals with facet dynamics in a physically accurate way. We studied in detail the dynamics of faceting in simple submicron surface structures [1], and proposed two approaches for the development of continuum models. First, we rigorously derived continuum kinetic models of the systems of interest, starting from step flow models. These models break down at singular points, which we identify as facet edges. The models are not applicable on facets, and the surface profile is obtained as a solution of the continuum model with boundary conditions at the singular points. Secondly, we showed [2] that if the existence of both steps and anti-steps in regions of small surface slope is taken into account, it is possible to construct continuum models that are valid even on facets. The solutions of both types of continuum models are in excellent agreement with step flow models. The resulting surface profiles are of relevance to experiments on decay of one dimensional periodic gratings. Our work points to a possible general continuum model for an accurate description of kinetics of crystalline surfaces below the roughening transition. [1] N. Israeli and D. Kandel, Phys. Rev. Lett. 80, 3300 (1998); N. Israeli and D. Kandel, Phys. Rev. B 60, 5946 (1999). [2] N. Israeli and D. Kandel, preprint.

  1. Determination of the distribution of sound source intensities in subsonic and supersonic jets

    NASA Technical Reports Server (NTRS)

    Damkevala, R. J.; Norman, R. S.

    1973-01-01

    Equations relating crossed beam space-time correlations to the sound source strength per unit length of an idealized jet are presented and applied to actual measurements in unheated jets at M = 0.71 and M = 1.0. The infrared crossed beam system was assembled and checked out. The prediction of the system's insensitivity to temperature fluctuations when set at 4.31 microns with a 0.08 micron bandpass was checked. Relative intensity profiles of density fluctuations for jets at M = 0.71, 1.0 and 1.94 were measured. These profiles differ considerably from velocity fluctuation profiles measured by other investigators with hotwires. The convection speeds also differ. Finally, the sound source strengths per unit length are obtained at various axial distances for the subsonic and sonic jet. The sonic jet shows peak source strength at an axial distance of six diameters.

  2. A methodology to study multiple sclerosis (MS) based on distributions of standardized intensities in segmented tissue regions

    NASA Astrophysics Data System (ADS)

    Lei, T.; Udupa, J. K.; Odhner, D.; Mishra, S.; Wu, G.; Schwartz, E.; Ying, G.-S.; Iwanaga, T.; Desiderio, L.; Balcer, L.

    2006-03-01

    This paper presents (1) an improved hierarchical method for segmenting the component tissue regions in fast spin echo T2 and PD images of the brain of Multiple Sclerosis (MS) patients, and (2) a methodology to characterize the disease utilizing the distributions of standardized T2 and PD intensities in the segmented tissue regions. First, the background intensity inhomogeneities are corrected and the intensity scales are standardized for all acquired images. The segmentation method imposes a feedback-like procedure on our previously developed hierarchical brain tissue segmentation method. With gradually simplified patterns in images and stronger evidences, pathological objects are recognized and segmented in an interplay fashion. After the brain parenchymal (BP) mask is generated, an under-estimated gray matter mask (uGM) and an over-estimated white matter mask (oWM) are created. Pure WM (PWM) and lesion (LS) masks are extracted from the all-inclusive oWM mask. By feedback, accurate GM and WM masks are subsequently formed. Finally, partial volume regions of GM and WM as well as Dirty WM (DWM) masks are generated. Intensity histograms and their parameters (peak height, peak location, and 25th, 50th and 75th percentile values) are computed for both T2 and PD images within each tissue region. Tissue volumes are also estimated. Spearman correlation coefficient rank test is then utilized to assess if there exists a trend between clinical states and the image-based parameters. This image analysis method has been applied to a data set consisting of 60 patients with MS and 20 normal controls. LS related parameters and clinical Extended Disability Status Scale (EDSS) scores demonstrate modest correlations. Almost every intensity-based parameter shows statistical difference between normal control and patient groups with a level better than 5%. These results can be utilized to monitor disease progression in MS.

  3. Continuum limbed robots for locomotion

    NASA Astrophysics Data System (ADS)

    Mutlu, Alper

    This thesis focuses on continuum robots based on pneumatic muscle technology. We introduce a novel approach to use these muscles as limbs of lightweight legged robots. The flexibility of the continuum legs of these robots offers the potential to perform some duties that are not possible with classical rigid-link robots. Potential applications are as space robots in low gravity, and as cave explorer robots. The thesis covers the fabrication process of continuum pneumatic muscles and limbs. It also provides some new experimental data on this technology. Afterwards, the designs of two different novel continuum robots - one tripod, one quadruped - are introduced. Experimental data from tests using the robots is provided. The experimental results are the first published example of locomotion with tripod and quadruped continuum legged robots. Finally, discussion of the results and how far this technology can go forward is presented.

  4. High-Intensity Radiated Field Fault-Injection Experiment for a Fault-Tolerant Distributed Communication System

    NASA Technical Reports Server (NTRS)

    Yates, Amy M.; Torres-Pomales, Wilfredo; Malekpour, Mahyar R.; Gonzalez, Oscar R.; Gray, W. Steven

    2010-01-01

    Safety-critical distributed flight control systems require robustness in the presence of faults. In general, these systems consist of a number of input/output (I/O) and computation nodes interacting through a fault-tolerant data communication system. The communication system transfers sensor data and control commands and can handle most faults under typical operating conditions. However, the performance of the closed-loop system can be adversely affected as a result of operating in harsh environments. In particular, High-Intensity Radiated Field (HIRF) environments have the potential to cause random fault manifestations in individual avionic components and to generate simultaneous system-wide communication faults that overwhelm existing fault management mechanisms. This paper presents the design of an experiment conducted at the NASA Langley Research Center's HIRF Laboratory to statistically characterize the faults that a HIRF environment can trigger on a single node of a distributed flight control system.

  5. Intensity-modulated linear-frequency-modulated continuous-wave lidar for distributed media: fundamentals of technique.

    PubMed

    Batet, Oscar; Dios, Federico; Comeron, Adolfo; Agishev, Ravil

    2010-06-10

    We analyze the intensity-modulation frequency-modulated continuous-wave (FMCW) technique for lidar remote sensing in the context of its application to distributed media. The goal of the technique is the reproduction of the sounded-medium profile along the emission path. A conceptual analysis is carried out to show the problems the basic version of the method presents for this application. The principal point is the appearance of a bandpass filtering effect, which seems to hinder its use in this context. A modified version of the technique is proposed to overcome this problem. A number of computer simulations confirm the ability of the modified FMCW technique to sound distributed media.

  6. Influence of scale-dependent fracture intensity on block size distribution and rock slope failure mechanisms in a DFN framework

    NASA Astrophysics Data System (ADS)

    Agliardi, Federico; Galletti, Laura; Riva, Federico; Zanchi, Andrea; Crosta, Giovanni B.

    2017-04-01

    An accurate characterization of the geometry and intensity of discontinuities in a rock mass is key to assess block size distribution and degree of freedom. These are the main controls on the magnitude and mechanisms of rock slope instabilities (structurally-controlled, step-path or mass failures) and rock mass strength and deformability. Nevertheless, the use of over-simplified discontinuity characterization approaches, unable to capture the stochastic nature of discontinuity features, often hampers a correct identification of dominant rock mass behaviour. Discrete Fracture Network (DFN) modelling tools have provided new opportunities to overcome these caveats. Nevertheless, their ability to provide a representative picture of reality strongly depends on the quality and scale of field data collection. Here we used DFN modelling with FracmanTM to investigate the influence of fracture intensity, characterized on different scales and with different techniques, on the geometry and size distribution of generated blocks, in a rock slope stability perspective. We focused on a test site near Lecco (Southern Alps, Italy), where 600 m high cliffs in thickly-bedded limestones folded at the slope scale impend on the Lake Como. We characterized the 3D slope geometry by Structure-from-Motion photogrammetry (range: 150-1500m; point cloud density > 50 pts/m2). Since the nature and attributes of discontinuities are controlled by brittle failure processes associated to large-scale folding, we performed a field characterization of meso-structural features (faults and related kinematics, vein and joint associations) in different fold domains. We characterized the discontinuity populations identified by structural geology on different spatial scales ranging from outcrops (field surveys and photo-mapping) to large slope sectors (point cloud and photo-mapping). For each sampling domain, we characterized discontinuity orientation statistics and performed fracture mapping and circular

  7. Numerical simulation of high intensity focused ultrasound temperature distribution for transcranial brain therapy

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; Wang, Yizhe; Zhou, Wenzheng; Zhang, Ji; Jian, Xiqi

    2017-03-01

    To provide a reference for the HIFU clinical therapeutic planning, the temperature distribution and lesion volume are analyzed by the numerical simulation. The adopted numerical simulation is based on a transcranial ultrasound therapy model, including an 8 annular-element curved phased array transducer. The acoustic pressure and temperature elevation are calculated by using the approximation of Westervelt Formula and the Pennes Heat Transfer Equation. In addition, the Time Reversal theory and eliminating hot spot technique are combined to optimize the temperature distribution. With different input powers and exposure times, the lesion volume is evaluated based on temperature threshold theory. The lesion region could be restored at the expected location by the time reversal theory. Although the lesion volume reduces after eliminating the peak temperature in the skull and more input power and exposure time is required, the injury of normal tissue around skull could be reduced during the HIFU therapy. The prediction of thermal deposition in the skull and the lesion region could provide a reference for clinical therapeutic dose.

  8. Bloodstream infections in intensive care unit patients: distribution and antibiotic resistance of bacteria

    PubMed Central

    Russotto, Vincenzo; Cortegiani, Andrea; Graziano, Giorgio; Saporito, Laura; Raineri, Santi Maurizio; Mammina, Caterina; Giarratano, Antonino

    2015-01-01

    Bloodstream infections (BSIs) are among the leading infections in critically ill patients. The case-fatality rate associated with BSIs in patients admitted to intensive care units (ICUs) reaches 35%–50%. The emergence and diffusion of bacteria with resistance to antibiotics is a global health problem. Multidrug-resistant bacteria were detected in 50.7% of patients with BSIs in a recently published international observational study, with methicillin resistance detected in 48% of Staphylococcus aureus strains, carbapenem resistance detected in 69% of Acinetobacter spp., in 38% of Klebsiella pneumoniae, and in 37% of Pseudomonas spp. Prior hospitalization and antibiotic exposure have been identified as risk factors for infections caused by resistant bacteria in different studies. Patients with BSIs caused by resistant strains showed an increased risk of mortality, which may be explained by a higher incidence of inappropriate empirical therapy in different studies. The molecular genetic characterization of resistant bacteria allows the understanding of the most common mechanisms underlying their resistance and the adoption of surveillance measures. Knowledge of epidemiology, risk factors, mechanisms of resistance, and outcomes of BSIs caused by resistant bacteria may have a major influence on global management of ICU patients. The aim of this review is to provide the clinician an update on BSIs caused by resistant bacteria in ICU patients. PMID:26300651

  9. Continuous Exercise but Not High Intensity Interval Training Improves Fat Distribution in Overweight Adults

    PubMed Central

    Keating, Shelley E.; Machan, Elizabeth A.; O'Connor, Helen T.; Gerofi, James A.; Sainsbury, Amanda; Caterson, Ian D.; Johnson, Nathan A.

    2014-01-01

    Objective. The purpose of this study was to assess the effect of high intensity interval training (HIIT) versus continuous aerobic exercise training (CONT) or placebo (PLA) on body composition by randomized controlled design. Methods. Work capacity and body composition (dual-energy X-ray absorptiometry) were measured before and after 12 weeks of intervention in 38 previously inactive overweight adults. Results. There was a significant group × time interaction for change in work capacity (P < 0.001), which increased significantly in CONT (23.8 ± 3.0%) and HIIT (22.3 ± 3.5%) but not PLA (3.1 ± 5.0%). There was a near-significant main effect for percentage trunk fat, with trunk fat reducing in CONT by 3.1 ± 1.6% and in PLA by 1.1 ± 0.4%, but not in HIIT (increase of 0.7 ± 1.0%) (P = 0.07). There was a significant reduction in android fat percentage in CONT (2.7 ± 1.3%) and PLA (1.4 ± 0.8%) but not HIIT (increase of 0.8 ± 0.7%) (P = 0.04). Conclusion. These data suggest that HIIT may be advocated as a time-efficient strategy for eliciting comparable fitness benefits to traditional continuous exercise in inactive, overweight adults. However, in this population HIIT does not confer the same benefit to body fat levels as continuous exercise training. PMID:24669314

  10. Relativistic Continuum Shell Model

    NASA Astrophysics Data System (ADS)

    Grineviciute, Janina; Halderson, Dean

    2011-04-01

    The R-matrix formalism of Lane and Thomas has been extended to the relativistic case so that the many-coupled channels problem may be solved for systems in which binary breakup channels satisfy a relative Dirac equation. The formalism was previously applied to the relativistic impulse approximation RIA and now we applied it to Quantum Hadrodynamics QHD in the continuum Tamm-Dancoff approximation TDA with the classical meson fields replaced by one-meson exchange potentials. None of the published QHD parameters provide a decent fit to the 15 N + p elastic cross section. The deficiency is also evident in inability of the QHD parameters with the one meson exchange potentials to reproduce the QHD single particle energies. Results with alternate parameters sets are presented. A. M. Lane and R. G. Thomas, R-Matrix Theory of Nuclear Reactions, Reviews of Modern Physics, 30 (1958) 257

  11. Generalized Kapchinskij-Vladimirskij Distribution and Beam Matrix for Phase-Space Manipulations of High-Intensity Beams

    NASA Astrophysics Data System (ADS)

    Chung, Moses; Qin, Hong; Davidson, Ronald C.; Groening, Lars; Xiao, Chen

    2016-11-01

    In an uncoupled linear lattice system, the Kapchinskij-Vladimirskij (KV) distribution formulated on the basis of the single-particle Courant-Snyder invariants has served as a fundamental theoretical basis for the analyses of the equilibrium, stability, and transport properties of high-intensity beams for the past several decades. Recent applications of high-intensity beams, however, require beam phase-space manipulations by intentionally introducing strong coupling. In this Letter, we report the full generalization of the KV model by including all of the linear (both external and space-charge) coupling forces, beam energy variations, and arbitrary emittance partition, which all form essential elements for phase-space manipulations. The new generalized KV model yields spatially uniform density profiles and corresponding linear self-field forces as desired. The corresponding matrix envelope equations and beam matrix for the generalized KV model provide important new theoretical tools for the detailed design and analysis of high-intensity beam manipulations, for which previous theoretical models are not easily applicable.

  12. Dose distribution analysis of physical and dynamic wedges by using an intensity-modulated radiotherapy MatriXX

    NASA Astrophysics Data System (ADS)

    Lee, Hae-Kag; Cho, Jae-Hwan; Cho, Dae-chul

    2013-05-01

    This study investigated differences between the physical wedge and the dynamic wedge distributions of radiation by using an intensity-modulated radiotherapy (ImRT) MatriXX. The linear accelerator used X-rays with energy levels of 6 MV and 10 MV to adjust the collimator by motoring the independent jaws (X1, X2, Y1, Y2) for setting wedge angles of 15, 30, 45, and 60 degrees. The collimator field size was set as 10 × 10 cm2 or 20 × 20 cm2 at the maximum dose point. The dose distribution for each wedge had ±5% and ±11% errors for field sizes of 10 × 10 cm2 and 20 × 20 cm2, respectively. The error was greatest at a wedge angle of 45 degrees and was pronounced at the end of the dynamic wedge where Y1 and Y2 met. Consequently, concluded that the dose distributions were similar for both wedges for the field size of a small beam profile. The beam dose was greatly increased at the end of the dynamic wedge. A more precise estimate of the therapeutic dose of radiation for a dynamic wedge that nearly matches that of the physical wedge can be achieved by correcting of the increasing part of the beam dose. The findings imply that a heavy wedge filter should not be used when calculating the isodose distribution and the therapeutic dose.

  13. Constraints on the Rupture of the October 21, 1868, Hayward Earthquake Determined From the Distribution of Modified Mercalli Intensity

    NASA Astrophysics Data System (ADS)

    Boatwright, J.; Bundock, H.

    2007-12-01

    The October 21, 1868, Hayward earthquake was the most damaging earthquake to occur in California in the half- century following the 1848 annexation. The earthquake shattered the city centers of Oakland and San Francisco, and cracked brick buildings as far away as Santa Rosa and Gilroy. We have re-evaluated MMI intensites at the 124 sites with damage or felt reports compiled by Toppozada et al. (1981), and added 26 sites where we obtained reports from newspapers and historical narratives. We used the 1878 Thompson and West Atlas of Alameda County to locate most of the specific buildings that were reported as damaged. The resulting ShakeMap interpolates the distribution of intensity along the Hayward fault, and the extent of shaking throughout the greater Bay Area and the San Joaquin Delta. Surprisingly, the highest intensities (MMI 8-9 to 9) are clustered near the middle of the fault rupture, in Hayward, San Leandro, and San Lorenzo. The intensities are lower (MMI 7- 8) at the ends of the fault rupture, in Berkeley and Warm Springs. The lack of strong shaking at either end of the fault rupture makes it hard to discern the rupture direction: the intensities observed at regional distances suggest that the rupture was stronger to the northwest towards Petaluma (MMI 7) and Martinez (MMI 7) than to the southeast towards Calaveras Valley (MMI 6-7) and Gilroy (MMI 6-7). The relatively low intensities in Oakland and Berkeley (MMI 7-8) suggest that the shallow locked zone near Piedmont, which Simpson et al. (2001) infer from the distribution of fault creep, did not rupture in the earthquake. This result appears to contradict Yu and Segall's (1996) conclusion that the fault slipped > 1 m in Berkeley. Given the large proportion of aseismic slip on Hayward fault, both observed geologically at the surface and inferred geodetically at depth, it is natural to propose that the rupture process of the 1868 earthquake comprised a series of disjoint asperity ruptures with variable

  14. Robust assessment of protein complex formation in vivo via single-molecule intensity distributions of autofluorescent proteins

    NASA Astrophysics Data System (ADS)

    Meckel, Tobias; Semrau, Stefan; Schaaf, Marcel J. M.; Schmidt, Thomas

    2011-07-01

    The formation of protein complexes or clusters in the plasma membrane is essential for many biological processes, such as signaling. We develop a tool, based on single-molecule microscopy, for following cluster formation in vivo. Detection and tracing of single autofluorescent proteins have become standard biophysical techniques. The determination of the number of proteins in a cluster, however, remains challenging. The reasons are (i) the poor photophysical stability and complex photophysics of fluorescent proteins and (ii) noise and autofluorescent background in live cell recordings. We show that, despite those obstacles, the accurate fraction of signals in which a certain (or set) number of labeled proteins reside, can be determined in an accurate an robust way in vivo. We define experimental conditions under which fluorescent proteins exhibit predictable distributions of intensity and quantify the influence of noise. Finally, we confirm our theoretical predictions by measurements of the intensities of individual enhanced yellow fluorescent protein (EYFP) molecules in living cells. Quantification of the average number of EYFP-C10HRAS chimeras in diffraction-limited spots finally confirm that the membrane anchor of human Harvey rat sarcoma (HRAS) heterogeneously distributes in the plasma membrane of living Chinese hamster ovary cells.

  15. Spatial distribution and health risk assessment for groundwater contamination from intensive pesticide use in arid areas.

    PubMed

    El Alfy, Mohamed; Faraj, Turki

    2017-02-01

    Arid and semiarid areas face major challenges in the management of scarce groundwater. This valuable resource is under pressures of population, economic expansion, contamination and over-exploitation. This research investigates groundwater vulnerability to pesticide contamination in the Al-Kharj area of Saudi Arabia. It explores the spatial distribution of pesticide concentrations in groundwater and other relevant factors. Thin permeable soils, permeable aquifers and shallow water tables, which are prevalent in the area, are especially vulnerable to pesticides. Analyses of 40 groundwater samples were performed using a gas chromatograph mass spectrometer coupled with a quadrupole mass spectrometer with a GC column. The analysis was conducted to detect 32 pesticides from different chemical families, and a total of 22 pesticides were detected. All 40 water samples were positive for at least one of the pesticides studied. In total, 21 compounds were above the quantification limit and 10 of them exceeded the legal limit. Total pesticide levels ranged from 0.18 to 2.21 μg/L, and 68 % of the analyzed samples exceeded the maximum allowable pesticide concentrations established by the European Community. Comparison of the daily intake peak (DIP) and daily intake mean (DIM) relative to the acceptable daily intake (ADI) shows that groundwater contamination with pesticides is a serious problem. Prolonged exposure to pesticides can cause adverse effects to human health and the ecosystem. Spatial distribution maps of groundwater contamination were developed using GIS. These maps will help risk managers identify vulnerable sources and provide a relative assessment of pesticide hazards to human health and the environment.

  16. Anaerobic degradation of solid material: importance of initiation centers for methanogenesis, mixing intensity, and 2D distributed model.

    PubMed

    Vavilin, V A; Angelidaki, I

    2005-01-05

    Batch anaerobic codigestion of municipal household solid waste (MHSW) and digested manure in mesophilic conditions was carried out. The different waste-to-biomass ratios and intensity of mixing were studied theoretically and experimentally. The experiments showed that when organic loading was high, intensive mixing resulted in acidification and failure of the process, while low mixing intensity was crucial for successful digestion. However, when loading was low, mixing intensity had no significant effect on the process. We hypothesized that mixing was preventing establishment of methanogenic zones in the reactor space. The methanogenic zones are important to withstand inhibition due to development of acids formed during acidogenesis. The 2D distributed models of symmetrical cylinder reactor are presented based on the hypothesis of the necessity of a minimum size of methanogenic zones that can propagate and establish a good methanogenic environment. The model showed that at high organic loading rate spatial separation of the initial methanogenic centers from active acidogenic areas is the key factor for efficient conversion of solids to methane. The initial level of methanogenic biomass in the initiation centers is a critical factor for the survival of these centers. At low mixing, most of the initiation methanogenic centers survive and expand over the reactor volume. However, at vigorous mixing the initial methanogenic centers are reduced in size, averaged over the reactor volume, and finally dissipate. Using fluorescence in situ hybridization, large irregular cocci of microorganisms were observed in the case with minimal mixing, while in the case with high stirring mainly dead cells were found. (c) 2004 Wiley Periodicals, Inc.

  17. Gating mechanism of mechanosensitive channel of large conductance: a coupled continuum mechanical-continuum solvation approach.

    PubMed

    Zhu, Liangliang; Wu, Jiazhong; Liu, Ling; Liu, Yilun; Yan, Yuan; Cui, Qiang; Chen, Xi

    2016-12-01

    Gating transition of the mechanosensitive channel of large conductance (MscL) represents a good example of important biological processes that are difficult to describe using atomistic simulations due to the large (submicron) length scale and long (millisecond) time scale. Here we develop a novel computational framework that tightly couples continuum mechanics with continuum solvation models to study the detailed gating behavior of E. coli-MscL. The components of protein molecules are modeled by continuum elements that properly describe their shape, material properties and physicochemical features (e.g., charge distribution). The lipid membrane is modeled as a three-layer material in which the lipid head group and tail regions are treated separately, taking into account the fact that fluidic lipid bilayers do not bear shear stress. Coupling between mechanical and chemical responses of the channel is realized by an iterative integration of continuum mechanics (CM) modeling and continuum solvation (CS) computation. Compared to previous continuum mechanics studies, the present model is capable of capturing the most essential features of the gating process in a much more realistic fashion: due mainly to the apolar solvation contribution, the membrane tension for full opening of MscL is reduced substantially to the experimental measured range. Moreover, the pore size stabilizes constantly during gating because of the intricate interactions of the multiple components of the system, implying the mechanism for sub-conducting states of MscL gating. A significant fraction ([Formula: see text]2/3) of the gating membrane strain is required to reach the first sub-conducting state of our model, which is featured with a relative conductance of 0.115 to the fully opened state. These trends agree well with experimental observations. We anticipate that the coupled CM/CS modeling framework is uniquely suited for the analysis of many biomolecules and their assemblies under external

  18. Measurements of the zenith sky intensity and spectral distribution during the solar eclipse of 12 november 1966 at bage, Brazil, and on an aircraft.

    PubMed

    Lloyd, J W; Silverman, S M

    1971-06-01

    Measurements of the zenith sky intensity and spectral distribution during the solar eclipse of 12 November 1966 at Bage, Brazil, and on an aircraft over the Atlantic are reported. These, together with measurements reported elsewhere from Santa Ines, Peru, and Quehua, Bolivia, are used to define the intensities and changes in spectral distribution during totality and to discuss the dependence of these on such factors as height and terrain.

  19. Potential geographic distribution of atmospheric nitrogen deposition from intensive livestock production in North Carolina, USA.

    PubMed

    Costanza, Jennifer K; Marcinko, Sarah E; Goewert, Ann E; Mitchell, Charles E

    2008-07-15

    To examine the consequences of increased spatial aggregation of livestock production facilities, we estimated the annual production of nitrogen in livestock waste in North Carolina, USA, and analyzed the potential distribution of atmospheric nitrogen deposition from confined animal feeding operations ("CAFO") lagoons. North Carolina is a national center for industrial livestock production. Livestock is increasingly being raised in CAFOs, where waste is frequently held, essentially untreated, in open-air lagoons. Reduced nitrogen in lagoons is volatilized as ammonia (NH(3)), transported atmospherically, and deposited to other ecosystems. The Albemarle-Pamlico Sound, NC, is representative of nitrogen-sensitive coastal waters, and is a major component of the second largest estuarine complex in the U.S. We used GIS to model the area of water in the Sound within deposition range of CAFOs. We also evaluated the number of lagoons within deposition range of each 1 km(2) grid cell of the state. We considered multiple scenarios of atmospheric transport by varying distance and directionality. Modeled nitrogen deposition rates were particularly elevated for the Coastal Plain. This pattern matches empirical data, suggesting that observed regional patterns of reduced nitrogen deposition can be largely explained by two factors: limited atmospheric transport distance, and spatial aggregation of CAFOs. Under our medium-distance scenario, a small portion (roughly 22%) of livestock production facilities contributes disproportionately to atmospheric deposition of nitrogen to the Albemarle-Pamlico Sound. Furthermore, we estimated that between 14-37% of the state receives 50% of the state's atmospheric nitrogen deposition from CAFO lagoons. The estimated total emission from livestock is 134,000 t NH(3) yr(-1), 73% of which originates from the Coastal Plain. Stronger waste management and emission standards for CAFOs, particularly those on the Coastal Plain nearest to sensitive water

  20. ESTIMATION METHOD OF THE HOMODYNED K-DISTRIBUTION BASED ON THE MEAN INTENSITY AND TWO LOG-MOMENTS

    PubMed Central

    DESTREMPES, FRANÇOIS; PORÉE, JONATHAN

    2013-01-01

    The homodyned K-distribution appears naturally in the context of random walks and provides a useful model for the distribution of the received intensity in a wide range of non-Gaussian scattering configurations, including medical ultrasonics. An estimation method for the homodyned K-distribution based on the first moment of the intensity and two log-moments (XU method), namely the X and U-statistics previously studied in the special case of the K-distribution, is proposed as an alternative to a method based on the first three moments of the intensity (MI method) or the amplitude (MA method), and a method based on the signal-to-noise ratio (SNR), the skewness and the kurtosis of two fractional orders of the amplitude (labeled RSK method). Properties of the X and U statistics for the homodyned K-distribution are proved, except for one conjecture. Using those properties, an algorithm based on the bisection method for monotonous functions was developed. The algorithm has a geometric rate of convergence. Various tests were performed to study the behavior of the estimators. It was shown with simulated data samples that the estimations of the parameters 1/α and 1/(κ + 1) of the homodyned K-distribution are preferable to the direct estimations of the clustering parameter α and the structure parameter κ (with respective relative root mean squared errors (RMSEs) of 0.63 and 0.13 as opposed to 1.04 and 4.37, when N = 1000). Tests on simulated ultrasound images with only diffuse scatterers (up to 10 per resolution cell) indicated that the XU estimator is overall more reliable than the other three estimators for the estimation of 1/α, with relative RMSEs of 0.79 (MI), 0.61 (MA), 0.53 (XU) and 0.67 (RSK). For the parameter 1/(κ + 1), the relative RMSEs were equal to 0.074 (MI), 0.075 (MA), 0.069 (XU) and 0.100 (RSK). In the case of a large number of scatterers (11 to 20 per resolution cell), the relative RMSEs of 1/α were equal to 1.43 (MI), 1.27 (MA), 1.25 (XU) and 1

  1. Atomic electron correlations in intense laser fields

    SciTech Connect

    Agostini, P A; DiMauro, L F; Kulander, K; Sheehy, B; Walker, B

    1998-09-03

    Abstract. This talk examines two distinct cases in strong opbical fields where electron correlation plays an important role in the dynamic.s. In the first. example, strong coupling in a two-electron-like system is manifested as an intensity-dependent splitting in the ionized electron energy distribution. This two-electron phenomenon (dubbed continuum-continuum Autler-Townes effect) is analogous to a strongly coupled two- level, one-electron atom but raises some intriguing questions regarding the exact nature of electron-electron correlation. The second case examines the evidence for two-electron ionization in the strong-field tunneling limit. Although our ability to describe the one- electron dynamics has obtained a quantitative level of understanding, a description of the two (multiple) electron ionization remains unc

  2. Atomic electron correlations in intense laser fields

    SciTech Connect

    DiMauro, L.F.; Sheehy, B.; Walker, B. Agostini, P.A. Kulander, K.C.

    1999-06-01

    This talk examines two distinct cases in strong optical fields where electron correlation plays an important role in the dynamics. In the first example, strong coupling in a two-electron-like system is manifested as an intensity-dependent splitting in the ionized electron energy distribution. This two-electron phenomenon (dubbed continuum-continuum Autler-Townes effect) is analogous to a strongly coupled two-level, one-electron atom but raises some intriguing questions regarding the exact nature of electron-electron correlation. The second case examines the evidence for two-electron ionization in the strong-field tunneling limit. Although our ability to describe the one-electron dynamics has obtained a quantitative level of understanding, a description of the two (multiple) electron ionization remains unclear. {copyright} {ital 1999 American Institute of Physics.}

  3. Atomic electron correlations in intense laser fields

    SciTech Connect

    DiMauro, L.F.; Sheehy, B.; Walker, B.; Agostini, P.A.; Kulander, K.C.

    1998-11-01

    This talk examines two distinct cases in strong optical fields where electron correlation plays an important role in the dynamics. In the first example, strong coupling in a two-electron-like system is manifested as an intensity-dependent splitting in the ionized electron energy distribution. This two-electron phenomenon (dubbed continuum-continuum Autler-Townes effect) is analogous to a strongly coupled two-level, one-electron atom but raises some intriguing questions regarding the exact nature of electron-electron correlation. The second case examines the evidence for two-electron ionization in the strong-field tunneling limit. Although their ability to describe the one-electron dynamics has obtained a quantitative level of understanding, a description of the two (multiple) electron ionization remains unclear.

  4. Atomic electron correlations in intense laser fields

    SciTech Connect

    DiMauro, L. F.; Sheehy, B.; Walker, B.; Agostini, P. A.; Kulander, K. C.

    1999-06-11

    This talk examines two distinct cases in strong optical fields where electron correlation plays an important role in the dynamics. In the first example, strong coupling in a two-electron-like system is manifested as an intensity-dependent splitting in the ionized electron energy distribution. This two-electron phenomenon (dubbed continuum-continuum Autler-Townes effect) is analogous to a strongly coupled two-level, one-electron atom but raises some intriguing questions regarding the exact nature of electron-electron correlation. The second case examines the evidence for two-electron ionization in the strong-field tunneling limit. Although our ability to describe the one-electron dynamics has obtained a quantitative level of understanding, a description of the two (multiple) electron ionization remains unclear.

  5. The Paranoid-Depressive Continuum

    ERIC Educational Resources Information Center

    Johnson, Betty J.

    1977-01-01

    Few investigators have attempted to lay a conceptual base for comparative studies of paranoia and depression within a single general framework. The paranoid-depressive continuum is an attempt to develop such a framework. (Author)

  6. The Paranoid-Depressive Continuum

    ERIC Educational Resources Information Center

    Johnson, Betty J.

    1977-01-01

    Few investigators have attempted to lay a conceptual base for comparative studies of paranoia and depression within a single general framework. The paranoid-depressive continuum is an attempt to develop such a framework. (Author)

  7. Differential absorption lidar measurements of H2O and O2 using a coherent white light continuum

    NASA Astrophysics Data System (ADS)

    Somekawa, T.; Manago, N.; Kuze, H.; Fujita, M.

    2016-10-01

    We applied a broadband and coherent white light continuum to differential absorption lidar (DIAL) detection of H2O and O2 profiles in the troposphere. The white light continuum can be generated by focusing high intensity femtosecond laser pulses at 800 nm into a Kr gas cell covering a broad spectral range from UV to mid-IR. Thus, the use of white light continuum potentially enables the DIAL measurement of several greenhouse and/or pollutant gases simultaneously while minimizing the lead time for developing a tunable light source. In order to demonstrate such capability, here we report the lidar measurements of H2O and O2. These molecular species exhibit absorption lines in the near IR region where relatively high intensity of the white light continuum is available. The white light continuum was transmitted through the atmosphere collinearly to the axis of a receiver telescope. Backscattered light was passed through bandpass filters (H2O On: 725 and 730 nm, H2O Off: 750 nm, O2 On: 760 nm, O2 Off: 780 nm), and was detected by a photomultiplier tube. The detection wavelengths were selected consecutively by rotating the filter wheels that contain five bandpass filters with an interval of 1 minute. In addition, we propose a method for retrieving vertical profiles of H2O by considering wavelength dependence of the aerosol extinction coefficient α and backscatter coefficient β. These results show that for achieving precise retrieval of H2O distribution, one needs to reduce the effect of aerosol temporal variations by means of long-time accumulation or simultaneous detection of the On- and Off-wavelength signals.

  8. Lattice Boltzmann algorithm for continuum multicomponent flow

    NASA Astrophysics Data System (ADS)

    Halliday, I.; Hollis, A. P.; Care, C. M.

    2007-08-01

    We present a multicomponent lattice Boltzmann simulation for continuum fluid mechanics, paying particular attention to the component segregation part of the underlying algorithm. In the principal result of this paper, the dynamics of a component index, or phase field, is obtained for a segregation method after U. D’Ortona [Phys. Rev. E 51, 3718 (1995)], due to Latva-Kokko and Rothman [Phys. Rev. E 71 056702 (2005)]. The said dynamics accord with a simulation designed to address multicomponent flow in the continuum approximation and underwrite improved simulation performance in two main ways: (i) by reducing the interfacial microcurrent activity considerably and (ii) by facilitating simulational access to regimes of flow with a low capillary number and drop Reynolds number [I. Halliday, R. Law, C. M. Care, and A. Hollis, Phys. Rev. E 73, 056708 (2006)]. The component segregation method studied, used in conjunction with Lishchuk’s method [S. V. Lishchuk, C. M. Care, and I. Halliday, Phys. Rev. E 67, 036701 (2003)], produces an interface, which is distributed in terms of its component index; however, the hydrodynamic boundary conditions which emerge are shown to support the notion of a sharp, unstructured, continuum interface.

  9. Spectral structure and stability studies on microstructure-fiber continuum

    NASA Astrophysics Data System (ADS)

    Gu, Xun; Kimmel, Mark; Zeek, Erik; Shreenath, Aparna P.; Trebino, Rick P.; Windeler, Robert S.

    2003-07-01

    Although previous direct measurements of the microstructure-fiber continuum have all showed a smooth and stable spectrum, our cross-correlation frequency-resolved optical gating (XFROG) full-intensity-and-phase characterization of the continuum pulse, utilizing sum-frequency-generation with a pre-characterized reference pulse and the angle-dithered-crystal technique, indicates that fine-scale spectral structure exists on a single-shot basis, contrary to previous observations. In particular, deep and fine oscillations are found in the retrieved spectrum, and the retrieved trace contains a "measles" pattern, whereas the measured trace and the independently-measured spectrum are rather smooth. The discrepancy is shown to be the result of unstable single-shot spectral structure. Although the XFROG measurement is not able to directly measure the single-shot fine structure in the trace, the redundancy of information in FROG traces enables the retrieval algorithm to correctly recognize the existence of the spectral fine structure, and restore the structure in the retrieved trace and spectrum. Numerical simulations have supported our hypothesis, and we directly observed the fine spectral structure in single-shot measurements of the continuum spectrum and the structure was seen to be highly unstable, the continuum spectrum appearing smooth only when many shots are averaged. Despite the structure and instability in the continuum spectrum, coherence experiments also reveal that the spectral phase is rather stable, being able to produce well-defined spectral fringes across the entire continuum bandwidth.

  10. Age-related prevalence, intensity and frequency distribution of gastrointestinal helminth infection in urban slum children from Kuala Lumpur, Malaysia.

    PubMed

    Bundy, D A; Kan, S P; Rose, R

    1988-01-01

    The gastrointestinal helminth infection status of 1574 children living in a slum area of Kuala Lumpur, Malaysia was assessed by quantitative coprology. Almost two-thirds were infected with Trichuris trichiura, 49.6% with Ascaris lumbricoides, and 5.3% with hookworm. Infection prevalence rose rapidly to a stable asymptote at 7 years of age, and the age-intensity profile was convex with maximal values in the 5-10 year age classes. This pattern was the same for males and females, but differed markedly between different ethnic groups. The frequency distributions of A. lumbricoides and T. trichiura were highly overdispersed (k values were 0.21 and 0.27, respectively), and age-dependent over the 0-8 year age classes. This suggests that the force of infection with these nematodes is lower in infants than in older children.

  11. Optimization of beam angles for intensity modulated radiation therapy treatment planning using genetic algorithm on a distributed computing platform.

    PubMed

    Nazareth, Daryl P; Brunner, Stephen; Jones, Matthew D; Malhotra, Harish K; Bakhtiari, Mohammad

    2009-07-01

    Planning intensity modulated radiation therapy (IMRT) treatment involves selection of several angle parameters as well as specification of structures and constraints employed in the optimization process. Including these parameters in the combinatorial search space vastly increases the computational burden, and therefore the parameter selection is normally performed manually by a clinician, based on clinical experience. We have investigated the use of a genetic algorithm (GA) and distributed-computing platform to optimize the gantry angle parameters and provide insight into additional structures, which may be necessary, in the dose optimization process to produce optimal IMRT treatment plans. For an IMRT prostate patient, we produced the first generation of 40 samples, each of five gantry angles, by selecting from a uniform random distribution, subject to certain adjacency and opposition constraints. Dose optimization was performed by distributing the 40-plan workload over several machines running a commercial treatment planning system. A score was assigned to each resulting plan, based on how well it satisfied clinically-relevant constraints. The second generation of 40 samples was produced by combining the highest-scoring samples using techniques of crossover and mutation. The process was repeated until the sixth generation, and the results compared with a clinical (equally-spaced) gantry angle configuration. In the sixth generation, 34 of the 40 GA samples achieved better scores than the clinical plan, with the best plan showing an improvement of 84%. Moreover, the resulting configuration of beam angles tended to cluster toward the patient's sides, indicating where the inclusion of additional structures in the dose optimization process may avoid dose hot spots. Additional parameter selection in IMRT leads to a large-scale computational problem. We have demonstrated that the GA combined with a distributed-computing platform can be applied to optimize gantry angle

  12. Coupling biophysical processes and water rights to simulate spatially distributed water use in an intensively managed hydrologic system

    NASA Astrophysics Data System (ADS)

    Han, Bangshuai; Benner, Shawn G.; Bolte, John P.; Vache, Kellie B.; Flores, Alejandro N.

    2017-07-01

    Humans have significantly altered the redistribution of water in intensively managed hydrologic systems, shifting the spatiotemporal patterns of surface water. Evaluating water availability requires integration of hydrologic processes and associated human influences. In this study, we summarize the development and evaluation of an extensible hydrologic model that explicitly integrates water rights to spatially distribute irrigation waters in a semi-arid agricultural region in the western US, using the Envision integrated modeling platform. The model captures both human and biophysical systems, particularly the diversion of water from the Boise River, which is the main water source that supports irrigated agriculture in this region. In agricultural areas, water demand is estimated as a function of crop type and local environmental conditions. Surface water to meet crop demand is diverted from the stream reaches, constrained by the amount of water available in the stream, the water-rights-appropriated amount, and the priority dates associated with particular places of use. Results, measured by flow rates at gaged stream and canal locations within the study area, suggest that the impacts of irrigation activities on the magnitude and timing of flows through this intensively managed system are well captured. The multi-year averaged diverted water from the Boise River matches observations well, reflecting the appropriation of water according to the water rights database. Because of the spatially explicit implementation of surface water diversion, the model can help diagnose places and times where water resources are likely insufficient to meet agricultural water demands, and inform future water management decisions.

  13. Compensation and Improvement of Intensity and Distribution in Reconstructed Image Using Adaptive Optics in Holographic Data Storage

    NASA Astrophysics Data System (ADS)

    Muroi, Tetsuhiko; Sekiguchi, Sayaka; Kinoshita, Nobuhiro; Ishii, Norihiko; Shimidzu, Naoki; Kamijo, Koji; Booth, Martin; Juskaitis, Rimas; Wilson, Tony

    2008-07-01

    We applied a genetic algorithm to adaptive optics to improve the intensity and distribution of reconstructed images in holographic data storage. This is a kind of combinatorial optimisation. In holographic data storage, the photopolymer recording medium shrinks during light curing and this shrinkage distorts the recorded interference fringes, which degrades the reconstructed data images. Although it is possible to compensate for the degradation in the reconstructed image by using adaptive optics, it has been difficult to compensate for the shrinkage distortion by using normal feedback control because the relationship between the reconstructed image and deformable mirror input is nonlinear. With our method, the inverse variance coefficient in a reconstructed image with bits that are all “1” increased from 10.3 to 14.7 dB, an improvement of 4.4 dB. Moreover, the intensity average of the reconstructed image with compensation was 1.7 times higher than the average without compensation. These results show that the combination of adaptive optics and a genetic algorithm is very effective for improving reconstructed images.

  14. Binomial probability distribution model-based protein identification algorithm for tandem mass spectrometry utilizing peak intensity information.

    PubMed

    Xiao, Chuan-Le; Chen, Xiao-Zhou; Du, Yang-Li; Sun, Xuesong; Zhang, Gong; He, Qing-Yu

    2013-01-04

    Mass spectrometry has become one of the most important technologies in proteomic analysis. Tandem mass spectrometry (LC-MS/MS) is a major tool for the analysis of peptide mixtures from protein samples. The key step of MS data processing is the identification of peptides from experimental spectra by searching public sequence databases. Although a number of algorithms to identify peptides from MS/MS data have been already proposed, e.g. Sequest, OMSSA, X!Tandem, Mascot, etc., they are mainly based on statistical models considering only peak-matches between experimental and theoretical spectra, but not peak intensity information. Moreover, different algorithms gave different results from the same MS data, implying their probable incompleteness and questionable reproducibility. We developed a novel peptide identification algorithm, ProVerB, based on a binomial probability distribution model of protein tandem mass spectrometry combined with a new scoring function, making full use of peak intensity information and, thus, enhancing the ability of identification. Compared with Mascot, Sequest, and SQID, ProVerB identified significantly more peptides from LC-MS/MS data sets than the current algorithms at 1% False Discovery Rate (FDR) and provided more confident peptide identifications. ProVerB is also compatible with various platforms and experimental data sets, showing its robustness and versatility. The open-source program ProVerB is available at http://bioinformatics.jnu.edu.cn/software/proverb/ .

  15. Correlation of spatial intensity distribution of light reaching the retina and restoration of vision by optogenetic stimulation

    NASA Astrophysics Data System (ADS)

    Shivalingaiah, Shivaranjani; Gu, Ling; Mohanty, Samarendra K.

    2011-03-01

    Stimulation of retinal neuronal cells using optogenetics via use of chanelrhodopsin-2 (ChR2) and blue light has opened up a new direction for restoration of vision with respect to treatment of Retinitis pigmentosa (RP). In addition to delivery of ChR2 to specific retinal layer using genetic engineering, threshold level of blue light needs to be delivered onto the retina for generating action potential and successful behavioral outcome. We report measurement of intensity distribution of light reaching the retina of Retinitis pigmentosa (RP) mouse models and compared those results with theoretical simulations of light propagation in eye. The parameters for the stimulating source positioning in front of eye was determined for optimal light delivery to the retina. In contrast to earlier viral method based delivery of ChR2 onto retinal ganglion cells, in-vivo electroporation method was employed for retina-transfection of RP mice. The behavioral improvement in mice with Thy1-ChR2-YFP transfected retina, expressing ChR2 in retinal ganglion cells, was found to correlate with stimulation intensity.

  16. The Role of Topography in the Distribution and Intensity of Damage Caused by Deer in Polish Mountain Forests

    PubMed Central

    Ciesielski, Mariusz; Stereńczak, Krzysztof; Borowski, Zbigniew

    2016-01-01

    The increase in the deer population observed in recent decades has strongly impacted forest regeneration and the forest itself. The reduction in the quality of raw wood material, as a consequence of deer-mediated damage, constitutes a significant burden on forest owners. The basis for the commencement of preventive actions in this setting is the understanding of the populations and behaviors of deer in their natural environment. Although multiple studies have been carried out regarding this subject, only a few suggested topography as an important factor that may influence the distribution and intensity of deer-mediated damage. The detailed terrain models based on LiDAR data as well as the data on damage caused by deer from the State Forests database enabled thorough analyses of the distribution and intensity of damage in relation to land form in this study. These analyses were performed on three mountain regions in Poland: the Western Sudety Mountains, the Eastern Sudety Mountains, and the Beskidy Mountains. Even though these three regions are located several dozen to several hundred kilometers apart from each other, not all evaluated factors appeared common among them, and therefore, these regions have been analyzed separately. The obtained results indicated that the forest damage caused by deer increased with increasing altitude above 1000 m ASL. However, much larger areas of damage by deer were observed at elevations ranging from 401 to 1000 m ASL than at elevations below 400 m ASL. Moreover, the locations of damage (forest thickets and old stands) indicated that red deer is the species that exerts the strongest pressure on forest ecosystems. Our results show the importance of deer foraging behavior to the structure of the environment. PMID:27851776

  17. The Role of Topography in the Distribution and Intensity of Damage Caused by Deer in Polish Mountain Forests.

    PubMed

    Bałazy, Radomir; Ciesielski, Mariusz; Stereńczak, Krzysztof; Borowski, Zbigniew

    2016-01-01

    The increase in the deer population observed in recent decades has strongly impacted forest regeneration and the forest itself. The reduction in the quality of raw wood material, as a consequence of deer-mediated damage, constitutes a significant burden on forest owners. The basis for the commencement of preventive actions in this setting is the understanding of the populations and behaviors of deer in their natural environment. Although multiple studies have been carried out regarding this subject, only a few suggested topography as an important factor that may influence the distribution and intensity of deer-mediated damage. The detailed terrain models based on LiDAR data as well as the data on damage caused by deer from the State Forests database enabled thorough analyses of the distribution and intensity of damage in relation to land form in this study. These analyses were performed on three mountain regions in Poland: the Western Sudety Mountains, the Eastern Sudety Mountains, and the Beskidy Mountains. Even though these three regions are located several dozen to several hundred kilometers apart from each other, not all evaluated factors appeared common among them, and therefore, these regions have been analyzed separately. The obtained results indicated that the forest damage caused by deer increased with increasing altitude above 1000 m ASL. However, much larger areas of damage by deer were observed at elevations ranging from 401 to 1000 m ASL than at elevations below 400 m ASL. Moreover, the locations of damage (forest thickets and old stands) indicated that red deer is the species that exerts the strongest pressure on forest ecosystems. Our results show the importance of deer foraging behavior to the structure of the environment.

  18. Cytoskeleton Dynamics: A Continuum Cooperative Hydrolysis Model

    NASA Astrophysics Data System (ADS)

    Xu, Jian-Wei; Cheng, Bo; Feng, Yu-Yu; Wang, Zi-Qing; Wang, Guo-Dong

    2015-05-01

    Cytoskeleton is a network of filamentous proteins, such as actin filaments and microtubules. We propose a continuum cooperative hydrolysis model which possesses exactly analytical solution to describe the dynamics of filament. The results show that the cooperativity leads to non negative-exponential distribution of T (ATP or GTP) subunits. As an application, we investigate the treadmilling phenomenon using our model. It is shown that the cooperativity remarkably affects the length of filament. Supported by Chinese Universities Scientific Fund under Grant No. 2014YB029 and National Natural Science Foundation of China under Grant No. 11205123

  19. Continuum-kinetic approach to sheath simulations

    NASA Astrophysics Data System (ADS)

    Cagas, Petr; Hakim, Ammar; Srinivasan, Bhuvana

    2016-10-01

    Simulations of sheaths are performed using a novel continuum-kinetic model with collisions including ionization/recombination. A discontinuous Galerkin method is used to directly solve the Boltzmann-Poisson system to obtain a particle distribution function. Direct discretization of the distribution function has advantages of being noise-free compared to particle-in-cell methods. The distribution function, which is available at each node of the configuration space, can be readily used to calculate the collision integrals in order to get ionization and recombination operators. Analytical models are used to obtain the cross-sections as a function of energy. Results will be presented incorporating surface physics with a classical sheath in Hall thruster-relevant geometry. This work was sponsored by the Air Force Office of Scientific Research under Grant Number FA9550-15-1-0193.

  20. Continuum Mechanics Based Bi-linear Shear Deformable Shell Element Using Absolute Nodal Coordinate Formulation

    DTIC Science & Technology

    2014-03-07

    the convergent solution in the case of the continuum mechanics based bi- linear shear deformable ANCF shell element. 5.3 Slit Annular Plate Subjected...UNCLASSIFIED: Distribution Statement A. Approved for public release. #24515 CONTINUUM MECHANICS BASED BI- LINEAR SHEAR DEFORMABLE SHELL ELEMENT...MAR 2014 2. REPORT TYPE Technical Report 3. DATES COVERED 07-01-2014 to 04-03-2014 4. TITLE AND SUBTITLE CONTINUUM MECHANICS BASED BI- LINEAR

  1. Lagrangian continuum dynamics in ALEGRA.

    SciTech Connect

    Wong, Michael K. W.; Love, Edward

    2007-12-01

    Alegra is an ALE (Arbitrary Lagrangian-Eulerian) multi-material finite element code that emphasizes large deformations and strong shock physics. The Lagrangian continuum dynamics package in Alegra uses a Galerkin finite element spatial discretization and an explicit central-difference stepping method in time. The goal of this report is to describe in detail the characteristics of this algorithm, including the conservation and stability properties. The details provided should help both researchers and analysts understand the underlying theory and numerical implementation of the Alegra continuum hydrodynamics algorithm.

  2. Three-dimensional inhomogeneous rain fields: implications for the distribution of intensity and polarization of the microwave thermal radiation.

    NASA Astrophysics Data System (ADS)

    Ilyushin, Yaroslaw; Kutuza, Boris

    Observations and mapping of the upwelling thermal radiation of the Earth is the very promising remote sensing technique for the global monitoring of the weather and precipitations. For reliable interpretation of the observation data, numerical model of the microwave radiative transfer in the precipitating atmosphere is necessary. In the present work, numerical simulations of thermal microwave radiation in the rain have been performed at three wavelengths (3, 8 and 22 mm). Radiative properties of the rain have been simulated using public accessible T-matrix codes (Mishchenko, Moroz) for non-spherical particles of fixed orientation and realistic raindrop size distributions (Marshall-Palmer) within the range of rain intensity 1-100 mm/h. Thermal radiation of infinite flat slab medium and isolated rain cell of kilometer size has been simulated with finite difference scheme for the vectorial radiative transfer equation (VRTE) in dichroic scattering medium. Principal role of cell structure of the rain field in the formation of angular and spatial distribution of the intensity and polarization of the upwelling thermal radiation has been established. Possible approaches to interpretation of satellite data are also discussed. It is necessary that spatial resolution of microwave radiometers be less than rain cell size. At the present time the resolution is approximately 15 km. It can be considerably improved, for example by two-dimensional synthetic aperture millimeter-wave radiometric interferometer for measuring full-component Stokes vector of emission from hydrometeors. The estimates show that in millimeter band it is possible to develop such equipment with spatial resolution of the order of 1-2 km, which is significantly less than the size of rain cell, with sensitivity 0.3-0.5 K. Under this condition the second Stokes parameter may by successfully measured and may be used for investigation of precipitation regions. Y-shaped phased array antenna is the most promising to

  3. A hybrid particle/continuum approach for nonequilibrium hypersonic flows

    NASA Astrophysics Data System (ADS)

    Wang, Wen-Lan

    A hybrid particle-continuum computational framework is developed and presented for simulating nonequilibrium hypersonic flows, aimed to be more accurate than conventional continuum methods and faster than particle methods. The frame work consists of the direct simulation Monte Carlo-Information Preservation (DSMC-IP) method coupled with a Navier-Stokes solver. Since the DSMC-IP method provides the macroscopic information at each time step, determination of the continuum fluxes across the interface between the particle and continuum domains becomes straightforward. Buffer and reservoir calls are introduced in the continuum domain and work as an extension of the particle domain. At the end of the particle movement phase, particles in either particle or buffer cells are retained. All simulated particles in the reservoir cells are first deleted for each time, step and re-generated based on the local cell values. The microscopic velocities for the newly generated particles are initialized to the Chapman-Enskog distribution using an acceptance-rejection scheme. Continuum breakdown in a flow is defined as when the continuum solution departs from the particle solution to at least 5%. Numerical investigations show that a Knudsen-number-like parameter can best predict the continuum breakdown in the flows of interest. Numerical experiments of hypersonic flows over a simple blunted cone and a much more complex hollow cylinder/flare are conducted. The solutions for the two geometries considered from the hybrid framework are compared with experimental data and pure particle solutions. Generally speaking, it is concluded that the hybrid approach works quite well. In the blunted cone flow, numerical accuracy is improved when 10 layers of buffer cells are employed and the continuum breakdown cut-off value is set to be 0.03. In the hollow cylinder/flare hybrid simulation, the size of the separation zone near the conjunction of the cylinder and flare is improved from the initial

  4. Investigations on the links between rain intensity or reflectivity structures estimated from radar and drop size distributions

    NASA Astrophysics Data System (ADS)

    Hachani, Sahar; Boudevillain, Brice; Bargaoui, Zoubeida; Delrieu, Guy

    2015-04-01

    During the first Special Observation Period (SOP) of the Hydrological cycle in the Mediterranean Experiment (HyMeX, www.hymex.org) held in fall 2012 in the Northwestern Mediterranean region, an observation network dedicated to rain studies was implemented in the Cévennes region, France. It was mainly constituted by weather radars, micro rain radars, disdrometers and rain gauges. Observations are performed by a network of 25 OTT Parsivel optical disdrometers distributed with inter-distances ranging from a few meters up to about one hundred kilometers. This presentation focuses on the comparison of one optical disdrometer observations located at Villeneuve-de-berg to observations using weather Météo-France / ARAMIS radar located at Bollène which is in a neighborhood of 60 km from the disdrometer.The period from September to November 2012 is studied. To analyze the structure of the rain observed by radar, a window of investigation centered on the disdrometer was selected and the mean spatial values, standard deviation, gradients, and intermittency of radar reflectivity or rainfall intensity were computed for a time step of 5 minutes.Four different windowsizes were analyzed: 1 km², 25 km², 100 km² and 400 km². On the other hand, the total concentration of drops Nt, the characteristic diameter of drops Dc, and a Gamma distribution shape parameter µ were estimated. Gamma distribution for the DSD related to disdrometer observations was estimated according to the modeling framework proposed by Yu et al. (2014). Correlation coefficient between intensity R obtained by the disdrometer and windowaverage R estimated using radar data is nearly 0.70 whatever the window. The highest value is found for the window 25 km² (0.74). Correlation coefficients between Dc and window average R vary from 0.35 for the window 1 km² to 0.4 for the window 400 km². So, they areweak and not sensitive to the choice of the window. Contrarily, formean radar reflectivityZ, correlation

  5. A catalogue of normalized intensity functions and polarization from a cloud of particles with a size distribution of alpha to the minus 4th power

    NASA Technical Reports Server (NTRS)

    Craven, P. D.; Gary, G. A.

    1972-01-01

    The Mie theory of light scattering by spheres was used to calculate the scattered intensity functions resulting from single scattering in a polydispersed collection of spheres. The distribution used behaves according to the inverse fourth power law; graphs and tables for the angular dependence of the intensity and polarization for this law are given. The effects of the particle size range and the integration increment are investigated.

  6. Direct reconstruction of the source intensity distribution of a clinical linear accelerator using a maximum likelihood expectation maximization algorithm.

    PubMed

    Papaconstadopoulos, P; Levesque, I R; Maglieri, R; Seuntjens, J

    2016-02-07

    Direct determination of the source intensity distribution of clinical linear accelerators is still a challenging problem for small field beam modeling. Current techniques most often involve special equipment and are difficult to implement in the clinic. In this work we present a maximum-likelihood expectation-maximization (MLEM) approach to the source reconstruction problem utilizing small fields and a simple experimental set-up. The MLEM algorithm iteratively ray-traces photons from the source plane to the exit plane and extracts corrections based on photon fluence profile measurements. The photon fluence profiles were determined by dose profile film measurements in air using a high density thin foil as build-up material and an appropriate point spread function (PSF). The effect of other beam parameters and scatter sources was minimized by using the smallest field size ([Formula: see text] cm(2)). The source occlusion effect was reproduced by estimating the position of the collimating jaws during this process. The method was first benchmarked against simulations for a range of typical accelerator source sizes. The sources were reconstructed with an accuracy better than 0.12 mm in the full width at half maximum (FWHM) to the respective electron sources incident on the target. The estimated jaw positions agreed within 0.2 mm with the expected values. The reconstruction technique was also tested against measurements on a Varian Novalis Tx linear accelerator and compared to a previously commissioned Monte Carlo model. The reconstructed FWHM of the source agreed within 0.03 mm and 0.11 mm to the commissioned electron source in the crossplane and inplane orientations respectively. The impact of the jaw positioning, experimental and PSF uncertainties on the reconstructed source distribution was evaluated with the former presenting the dominant effect.

  7. Theoretical analysis of the background intensity distribution in X-ray Birefringence Imaging using synchrotron bending-magnet radiation

    SciTech Connect

    Sutter, John P. Dolbnya, Igor P.; Collins, Stephen P.; Harris, Kenneth D. M.; Edwards-Gau, Gregory R.; Palmer, Benjamin A.

    2015-04-28

    In the recently developed technique of X-ray Birefringence Imaging, molecular orientational order in anisotropic materials is studied by exploiting the birefringence of linearly polarized X-rays with energy close to an absorption edge of an element in the material. In the experimental setup, a vertically deflecting high-resolution double-crystal monochromator is used upstream from the sample to select the appropriate photon energy, and a horizontally deflecting X-ray polarization analyzer, consisting of a perfect single crystal with a Bragg reflection at Bragg angle of approximately 45°, is placed downstream from the sample to measure the resulting rotation of the X-ray polarization. However, if the experiment is performed on a synchrotron bending-magnet beamline, then the elliptical polarization of the X-rays out of the electron orbit plane affects the shape of the output beam. Also, because the monochromator introduces a correlation between vertical position and photon energy to the X-ray beam, the polarization analyzer does not select the entire beam, but instead selects a diagonal stripe, the slope of which depends on the Bragg angles of the monochromator and the polarization analyzer. In the present work, the final background intensity distribution is calculated analytically because the phase space sampling methods normally used in ray traces are too inefficient for this setup. X-ray Birefringence Imaging data measured at the Diamond Light Source beamline B16 agree well with the theory developed here.

  8. Effects of light intensity on the distribution of anthocyanins in Kalanchoe brasiliensis Camb. and Kalanchoe pinnata (Lamk.) Pers.

    PubMed

    Cruz, Bruna P; Chedier, Luciana M; Peixoto, Paulo H P; Fabri, Rodrigo L; Pimenta, Daniel S

    2012-03-01

    This paper compares two medicinal species of Kalanchoe, which are often used interchangeably by the population, regarding the distribution of anthocyanins under the influence of four luminosity levels for 6 months. For the morphoanatomical analysis, the 6th stem node of each plant was sectioned. Usual histochemical tests revealed the presence of anthocyanins by cross sections of the stems, petioles and leaf blades. The petioles and leaf blades were submitted to the extraction with acidified methanol, and the anthocyanins were quantified by spectrophotometric readings. At the macroscopic level, it was noticed for both species a higher presence of anthocyanins in stems and petioles of plants under full sunlight. The microscopy of K. brasiliensis stems evidenced the deposition of anthocyanins in the subjacent tissue to the epidermis and cortex, which increased with light intensity. In K. pinnata a subepidermal collenchyma was observed, which interfered in the visualization of anthocyanins. In petioles and leaf blades of K. brasiliensis the deposition of anthocyanins was peripheral, and in K. pinnata it was also throughout the cortex. The quantification of anthocyanins in petioles showed in 70% of light higher averages than in 25%, but in leaf blades there were no significant results. This study contributes to the pharmacognosy of Kalanchoe and it is sustained by the description of flavonoids as biological markers of the genus.

  9. Theoretical analysis of the background intensity distribution in X-ray Birefringence Imaging using synchrotron bending-magnet radiation

    NASA Astrophysics Data System (ADS)

    Sutter, John P.; Dolbnya, Igor P.; Collins, Stephen P.; Harris, Kenneth D. M.; Edwards-Gau, Gregory R.; Palmer, Benjamin A.

    2015-04-01

    In the recently developed technique of X-ray Birefringence Imaging, molecular orientational order in anisotropic materials is studied by exploiting the birefringence of linearly polarized X-rays with energy close to an absorption edge of an element in the material. In the experimental setup, a vertically deflecting high-resolution double-crystal monochromator is used upstream from the sample to select the appropriate photon energy, and a horizontally deflecting X-ray polarization analyzer, consisting of a perfect single crystal with a Bragg reflection at Bragg angle of approximately 45°, is placed downstream from the sample to measure the resulting rotation of the X-ray polarization. However, if the experiment is performed on a synchrotron bending-magnet beamline, then the elliptical polarization of the X-rays out of the electron orbit plane affects the shape of the output beam. Also, because the monochromator introduces a correlation between vertical position and photon energy to the X-ray beam, the polarization analyzer does not select the entire beam, but instead selects a diagonal stripe, the slope of which depends on the Bragg angles of the monochromator and the polarization analyzer. In the present work, the final background intensity distribution is calculated analytically because the phase space sampling methods normally used in ray traces are too inefficient for this setup. X-ray Birefringence Imaging data measured at the Diamond Light Source beamline B16 agree well with the theory developed here.

  10. Combining intensity correlation analysis and MALDI imaging to study the distribution of flavonols and dihydrochalcones in Golden Delicious apples.

    PubMed

    Franceschi, Pietro; Dong, Yonghui; Strupat, Kerstin; Vrhovsek, Urska; Mattivi, Fulvio

    2012-02-01

    Mass spectrometry-based imaging techniques applied to small molecules complement the growing research field of metabolomics and can be used to interpret many important biological processes occurring in plants. In untargeted imaging applications, chemical identification is a critical step since it cannot take advantage of separative techniques applied to neutral molecules (e.g. liquid chromatography). The use of high resolution spectrometers is of great help, but fragmentation experiments are often necessary. In many cases, the information on ion fragmentation is embedded in the data sets, because analytes break up during ionization, but the extraction of this information is not easy considering the complexity of the imaging data files. Here an approach is proposed for applying conventional untargeted MALDI (matrix-assisted laser desorption ionization) profiling and advanced data analysis to perform imaging of metabolites in apple tissues. The pipeline, based on intensity correlation analysis, is used to extract fragmentation information from untargeted, high resolution, wide range mass spectra and to reconstruct compound-specific images which can be used for interpretation purposes. The proposed approach was used to investigate the distribution of glycosylated flavonols and dihydrochalcones in Golden Delicious apples. The results indicate that the method is effective, showing a high potential for ascertaining detailed metabolite localization.

  11. Introduction and survey on continuum models for repetitive lattice structures

    NASA Technical Reports Server (NTRS)

    Weisstein, L. S.

    1983-01-01

    A brief introduction and survey to aid and familiarize researchers interested in the use of continuum modeling procedures applied towards large space structure technology are presented. The use of such structural models for the distributed control of large flexible lattice structures offers a significant advantage over a numerical approach.

  12. LASER BEAMS. CAVITIES: Formation of a beam with a uniform intensity distribution in a CO2 laser with a generalised confocal cavity

    NASA Astrophysics Data System (ADS)

    Gurin, O. V.; Yepishin, V. A.; Maslov, Vyacheslav A.; Militinskii, I. M.; Svich, V. A.; Topkov, A. N.

    1998-05-01

    A description is given of a method of forming, in a composite confocal cavity, non-Gaussian light beams with a uniform intensity distribution. The method is based on the use of a reflector with discretely distributed absorbing or scattering inhomogeneities. Theoretical and experimental confirmations are reported of the generation of such beams at the output of a CO2 laser with a nonuniform amplitude-stepped mirror.

  13. Homogenization of a Cauchy continuum towards a micromorphic continuum

    NASA Astrophysics Data System (ADS)

    Hütter, Geralf

    2017-02-01

    The micromorphic theory of Eringen and Mindlin, including special cases like strain gradient theory or Cosserat theory, is widely used to model size effects and localization phenomena. The heuristic construction of such theories based on thermodynamic considerations is well-established. However, the identification of corresponding constitutive laws and of the large number of respective constitutive parameters limits the practical application of such theories. In the present contribution, a closed procedure for the homogenization of a Cauchy continuum at the microscale towards a fully micromorphic continuum is derived including explicit definitions of all involved generalized macroscopic stress and deformation measures. The boundary value problem to be solved on the microscale is formulated either for using static or kinematic boundary conditions. The procedure is demonstrated with an example.

  14. Molecular surface-free continuum model for electrodiffusion processes

    PubMed Central

    Lu, Benzhuo; McCammon, J. Andrew

    2008-01-01

    Incorporation of van der Waals interactions enables the continuum model of electrodiffusion in biomolecular system to avoid the artifacts of introducing a molecular surface and the painful task of the surface mesh generation. Calculation examples show that the electrostatics, diffusion-reaction kinetics, and molecular surface defined as an isosurface of a certain density distribution can be extracted from the solution of the Poisson-Nernst-Planck equations using this model. The molecular surface-free model enables a wider usage of some modern numerical methodologies such as finite element methods for biomolecular modeling, and sheds light on a new paradigm of continuum modeling for biomolecular systems. PMID:19461944

  15. Relationship study on land use spatial distribution structure and energy-related carbon emission intensity in different land use types of Guangdong, China, 1996-2008.

    PubMed

    Huang, Yi; Xia, Bin; Yang, Lei

    2013-01-01

    This study attempts to discuss the relationship between land use spatial distribution structure and energy-related carbon emission intensity in Guangdong during 1996-2008. We quantized the spatial distribution structure of five land use types including agricultural land, industrial land, residential and commercial land, traffic land, and other land through applying spatial Lorenz curve and Gini coefficient. Then the corresponding energy-related carbon emissions in each type of land were calculated in the study period. Through building the reasonable regression models, we found that the concentration degree of industrial land is negatively correlated with carbon emission intensity in the long term, whereas the concentration degree is positively correlated with carbon emission intensity in agricultural land, residential and commercial land, traffic land, and other land. The results also indicate that land use spatial distribution structure affects carbon emission intensity more intensively than energy efficiency and production efficiency do. These conclusions provide valuable reference to develop comprehensive policies for energy conservation and carbon emission reduction in a new perspective.

  16. Relationship Study on Land Use Spatial Distribution Structure and Energy-Related Carbon Emission Intensity in Different Land Use Types of Guangdong, China, 1996–2008

    PubMed Central

    Huang, Yi; Yang, Lei

    2013-01-01

    This study attempts to discuss the relationship between land use spatial distribution structure and energy-related carbon emission intensity in Guangdong during 1996–2008. We quantized the spatial distribution structure of five land use types including agricultural land, industrial land, residential and commercial land, traffic land, and other land through applying spatial Lorenz curve and Gini coefficient. Then the corresponding energy-related carbon emissions in each type of land were calculated in the study period. Through building the reasonable regression models, we found that the concentration degree of industrial land is negatively correlated with carbon emission intensity in the long term, whereas the concentration degree is positively correlated with carbon emission intensity in agricultural land, residential and commercial land, traffic land, and other land. The results also indicate that land use spatial distribution structure affects carbon emission intensity more intensively than energy efficiency and production efficiency do. These conclusions provide valuable reference to develop comprehensive policies for energy conservation and carbon emission reduction in a new perspective. PMID:23476128

  17. Fault damage zone volume and initial salinity distribution determine intensity of shallow aquifer salinisation in subsurface storage

    NASA Astrophysics Data System (ADS)

    Tillner, Elena; Langer, Maria; Kempka, Thomas; Kühn, Michael

    2016-03-01

    Injection of fluids into deep saline aquifers causes a pore pressure increase in the storage formation, and thus displacement of resident brine. Via hydraulically conductive faults, brine may migrate upwards into shallower aquifers and lead to unwanted salinisation of potable groundwater resources. In the present study, we investigated different scenarios for a potential storage site in the Northeast German Basin using a three-dimensional (3-D) regional-scale model that includes four major fault zones. The focus was on assessing the impact of fault length and the effect of a secondary reservoir above the storage formation, as well as model boundary conditions and initial salinity distribution on the potential salinisation of shallow groundwater resources. We employed numerical simulations of brine injection as a representative fluid. Our simulation results demonstrate that the lateral model boundary settings and the effective fault damage zone volume have the greatest influence on pressure build-up and development within the reservoir, and thus intensity and duration of fluid flow through the faults. Higher vertical pressure gradients for short fault segments or a small effective fault damage zone volume result in the highest salinisation potential due to a larger vertical fault height affected by fluid displacement. Consequently, it has a strong impact on the degree of shallow aquifer salinisation, whether a gradient in salinity exists or the saltwater-freshwater interface lies below the fluid displacement depth in the faults. A small effective fault damage zone volume or low fault permeability further extend the duration of fluid flow, which can persist for several tens to hundreds of years, if the reservoir is laterally confined. Laterally open reservoir boundaries, large effective fault damage zone volumes and intermediate reservoirs significantly reduce vertical brine migration and the potential of freshwater salinisation because the origin depth of displaced

  18. Prediction and Measurement of X-Ray Spectral and Intensity Distributions from Low Energy Electron Impact Sources

    NASA Technical Reports Server (NTRS)

    Edwards, David L.

    1999-01-01

    In-vacuum electron beam welding is a technology that NASA considered as a joining technique for manufacture of space structures. The interaction of energetic electrons with metal produces x-rays. The radiation exposure to astronauts performing the in-vacuum electron beam welding must be characterized and minimized to insure safe operating conditions. This investigation characterized the x-ray environment due to operation of an in-vacuum electron beam welding tool. NASA, in a joint venture with the Russian Space Agency, was scheduled to perform a series of welding in space experiments on board the United States Space Shuttle. This series of experiments was named the International Space Welding Experiment (ISWE). The hardware associated with the ISWE was leased to NASA, by the Paton Welding Institute (PWI) in Ukraine, for ground based welding experiments in preparation for flight. Two tests were scheduled, using the ISWE electron beam welding tool, to characterize the radiation exposure to an astronaut during the operation of the ISWE. These radiation exposure tests consisted of Thermoluminescence Dosimeters (TLD's) shielded with material currently used by astronauts during Extra Vehicular Activities (EVA) and exposed to x-ray radiation generated by operation of an in-vacuum electron beam welding tool. This investigation was the first known application of TLD's to measure absorbed dose from x-rays of energy less than 10 KeV. The ISWE hardware was returned to Ukraine before the issue of adequate shielding for the astronauts was verified. Therefore, alternate experimental and analytical methods were developed to measure and predict the x-ray spectral and intensity distribution generated by electron impact with metal. These x-ray spectra were used to calculate the absorbed radiation dose to astronauts. These absorbed dose values were compared to TLD measurements obtained during actual operation of the in-vacuum electron beam welding tool. The calculated absorbed dose

  19. Prediction and Measurement of X-Ray Spectral and Intensity Distributions from Low Energy Electron Impact Sources

    NASA Technical Reports Server (NTRS)

    Edwards, David L.

    1999-01-01

    In-vacuum electron beam welding is a technology that NASA considered as a joining technique for manufacture of space structures. The interaction of energetic electrons with metal produces x-rays. The radiation exposure to astronauts performing the in-vacuum electron beam welding must be characterized and minimized to insure safe operating conditions. This investigation characterized the x-ray environment due to operation of an in-vacuum electron beam welding tool. NASA, in a joint venture with the Russian Space Agency, was scheduled to perform a series of welding in space experiments on board the United States Space Shuttle. This series of experiments was named the International Space Welding Experiment (ISWE). The hardware associated with the ISWE was leased to NASA, by the Paton Welding Institute (PWI) in Ukraine, for ground based welding experiments in preparation for flight. Two tests were scheduled, using the ISWE electron beam welding tool, to characterize the radiation exposure to an astronaut during the operation of the ISWE. These radiation exposure tests consisted of Thermoluminescence Dosimeters (TLD's) shielded with material currently used by astronauts during Extra Vehicular Activities (EVA) and exposed to x-ray radiation generated by operation of an in-vacuum electron beam welding tool. This investigation was the first known application of TLD's to measure absorbed dose from x-rays of energy less than 10 KeV. The ISWE hardware was returned to Ukraine before the issue of adequate shielding for the astronauts was verified. Therefore, alternate experimental and analytical methods were developed to measure and predict the x-ray spectral and intensity distribution generated by electron impact with metal. These x-ray spectra were used to calculate the absorbed radiation dose to astronauts. These absorbed dose values were compared to TLD measurements obtained during actual operation of the in-vacuum electron beam welding tool. The calculated absorbed dose

  20. The effect of human immunodeficiency virus infection on the distribution and outcome of pneumonia in intensive care units.

    PubMed

    Tucker, K J; Anton, B; Tucker, H J

    1992-12-01

    To determine the frequency and distribution of pneumonia in an intensive care unit (ICU), we retrospectively examined the records of 1,854 consecutive ICU admissions between January 1987 and April 1990. A total of 266 patients met criteria for pneumonia (unilateral or bilateral infiltrate by chest roentgenogram, plus 2 of the following: leukocyte count > 10 x 10(9) per liter, temperature > 38.5 degrees C, or culture of blood or sputum positive for pathogens). Pneumocystis carinii pneumonia in patients infected with the human immunodeficiency virus was the most frequent cause (28%) precipitating an ICU admission in this series of patients. Streptococcus pneumoniae (13%), Staphylococcus aureus (8%), Haemophilus influenzae (4%), and viruses (4%) were also commonly observed. Overall mortality was 20%. An APACHE II score of greater than 24, the need for intubation, and the presence of P carinii were predictive of increased mortality. Age, sex, and length of stay did not predict final results. Patients with P carinii pneumonia who required intubation had an overall mortality of 54%, which was higher than patients without P carinii pneumonia who required intubation (P < .05). Our experience shows the changing spectrum of pneumonia in ICUs. In contrast to reports of a decade ago in which S pneumoniae and Pseudomonas aeruginosa are cited as most common, P carinii is now most prevalent in our ICU. Although our findings reflect the increasing incidence of human immunodeficiency virus infection in San Francisco, California, they may also be pertinent to other areas in the United States where the incidence of this infection continues to increase.

  1. Investigation on the similarity law of low-pressure glow discharges based on the light intensity distributions in geometrically similar gaps

    NASA Astrophysics Data System (ADS)

    Fu, Yangyang; Wang, Xinxin; Zou, Xiaobing; Yang, Shuo; Verboncoeur, John P.; Christlieb, Andrew J.

    2017-08-01

    Experimental investigation of the light intensity distributions of a low-pressure glow discharge is carried out in several pairs of geometrically similar plane-parallel gaps, of which the aspect ratios and the products of the linear dimension and the gas pressure are the same. The discharge images are captured using a Charge Coupled Device camera, from which the corresponding axial light intensity distributions are presented. Based on the obtained light intensity distributions, the thicknesses of cathode fall layers were identified by measuring the distance between the peak glow position and the cathode boundary. The influence of the discharge current on the light intensity distributions on the geometrically similar gaps is also investigated. It was found that, for discharges in each pair of geometrically similar gaps, the reduced cathode fall thicknesses are observed to be identical when the discharge currents are the same. The similarity relation of the cathode fall thickness is validated for low-pressure glow discharges in gaps for different aspect ratios.

  2. Diameter Distributions and Basal Area of Pines and Hardwoods 12 Years Following Vairous Methods and Intensities of Site Preparation in the Georgia Peidmont

    Treesearch

    Timothy B. Harrington; M. Boyd Edwards

    1997-01-01

    Twelve years after various methods and intensities of site preparation in the Georgia Piedmont, diameter distributions and basal area (BA) of pines and hardwoods varied considerably among treatments. Site preparation reduced hardwood basal area to 36 percent of that observed in clearcut-only plots. As a result, planted-pine BA in the presence of site preparation was 2...

  3. Continuum Mapping of Low Mass Star Forming Cores using SCUBA

    NASA Astrophysics Data System (ADS)

    Shirley, Y. L.; Evans, N. J.; Rawlings, J. M. C.; Gregersen, E. M.

    1998-12-01

    Recent studies in star formation have been guided by a putative evolutionary sequence based on the spectral energy distribution (SED) of young stellar objects. We are testing this idea by tracing the changes in the distribution of matter across this sequence. We have obtained 850 and 450 micron continuum maps of 21 low mass cores with SED's ranging from Pre-protostellar to Class I (20K < Tbol < 140K) using the SCUBA bolometer array at the JCMT. By combining our maps with continuum emission at other wavelengths and using a radiative transport code, we can compare model predictions of the spatial extent of emission and the SED with observations. This method allows for a self-consistent calculation of the temperature distribution and for smoothing effects caused by a finite beam. We present observations and models of the dust density and temperature distributions as well as SEDs for our sources.

  4. Continuum effects in nuclear transfer reactions

    SciTech Connect

    Marta, H. D.; Donangelo, R.; Fernandez Niello, J. O.; Pacheco, A. J.

    2007-02-12

    We develop a semiclassical calculation for nuclear transfer reactions where the continuum is treated in an exact way, and compare the results with those of a treatment in which the continuum is neglected. We conclude that the influence of the continuum is very important for weakly bound reactants.

  5. Electron transfer to continuum states

    SciTech Connect

    Macek, J.H. |

    1994-12-31

    Gene Rudd`s analysis of doubly differential cross sections for the ionization of He atoms by proton impact suggested that electrons were being carried along by the proton for a short period of time after being ejected from the target region. Normally, this would represent an electron capture event in which an excited state of atomic hydrogen is formed. Because the electron ends up ionized it was recognized that these states of the proton must be continuum states. This insight was confirmed by observations of the continuum electron capture (CEC) cusp when the electron velocity equals the proton velocity in the final state. The impact of this idea upon the theory of ionization at high energies is reviewed.

  6. Continuum and line emission in Cygnus A

    NASA Astrophysics Data System (ADS)

    Stockton, Alan; Ridgway, Susan E.; Lilly, Simon J.

    1994-08-01

    We present the results from (1) imaging observations of Cygnus A in five essentially line-free continuum bands with central wavelengths ranging from 0.34 to 2.1 microns. (2) imaging observations in five narrowband filters centered on the emission lines H beta(O III) lambda5007, H alpha(N II) lambda6583, and (S II) lambda lambda6716, 6731, and (3) deep spectroscopy covering the entire central region of Cyg A. We confirm that the featureless spectrum component is to be identified with the prominent double morphology at the center of Cyg A, but uncertainties in the distribution of the dust in this region tend to limit the accuracy with which we can determine its morphology and spectral-energy distribution (SED). From regions that appear to be least affected by obscuration, we find fv is approximately v-0.1 for this component. This SED could be consistent with free-free emission, a population of young stars, or a quasar continuum scattered by electrons, but probably not with a quasar continuum scattered by dust, which would be bluer. Our spectroscopy places an upper limit on the equivalent width of broad H beta that is well below that of typical quasars, showing that this flat-spectrum component (FSC) is almost certainly not dominated by scattered quasar radiation. Appeals to scattering by hot electrons to smear the scattered broad lines into invisibility appear to fail because the large density scale height of the electrons and the inefficiency of electron scattering should result in smoother and more extensive structure than we observe. Although the relative SED is consistent with free-free emission, the required amount of hot gas violates other observational constraints. At high angular resolution, the apparent morphology of the FSC is spiral-like. Although this impression may be partly due to obscuration, the distribution of the dust itself only serves to reinforce the spiral-like nature of the material with which it is associated. We conclude that the FSC is most

  7. ALMA Band 8 Continuum Emission from Orion Source I

    NASA Astrophysics Data System (ADS)

    Hirota, Tomoya; Machida, Masahiro N.; Matsushita, Yuko; Motogi, Kazuhito; Matsumoto, Naoko; Kim, Mi Kyoung; Burns, Ross A.; Honma, Mareki

    2016-12-01

    We have measured continuum flux densities of a high-mass protostar candidate, a radio source I in the Orion KL region (Orion Source I) using the Atacama Large Millimeter/Submillimeter Array (ALMA) at band 8 with an angular resolution of 0.″1. The continuum emission at 430, 460, and 490 GHz associated with Source I shows an elongated structure along the northwest-southeast direction perpendicular to the so-called low-velocity bipolar outflow. The deconvolved size of the continuum source, 90 au × 20 au, is consistent with those reported previously at other millimeter/submillimeter wavelengths. The flux density can be well fitted to the optically thick blackbody spectral energy distribution, and the brightness temperature is evaluated to be 700-800 K. It is much lower than that in the case of proton-electron or H- free-free radiations. Our data are consistent with the latest ALMA results by Plambeck & Wright, in which the continuum emission was proposed to arise from the edge-on circumstellar disk via thermal dust emission, unless the continuum source consists of an unresolved structure with a smaller beam filling factor.

  8. Finsler-Geometric Continuum Mechanics

    DTIC Science & Technology

    2016-05-01

    continuum mechanics/ physics of deformable bodies) is emphasized in the present report. In this context, fields describing the motion of material particles ...to physical problems of tensile fracture, shear localization, and cavitation in solid bodies. The pseudo-Finsler approach is demonstrated to be more...Weyl-type transformation of the fundamental tensor, analytical and numerical solutions of representative example problems offer new physical insight

  9. Continuum description for jointed media

    SciTech Connect

    Thomas, R.K.

    1982-04-01

    A general three-dimensional continuum description is presented for a material containing regularly spaced and approximately parallel jointing planes within a representative elementary volume. Constitutive relationships are introduced for linear behavior of the base material and nonlinear normal and shear behavior across jointing planes. Furthermore, a fracture permeability tensor is calculated so that deformation induced alterations to the in-situ values can be measured. Examples for several strain-controlled loading paths are presented.

  10. Continuum representations of cellular solids

    NASA Astrophysics Data System (ADS)

    Neilsen, M. K.

    1993-09-01

    Cellular materials consist of interconnected struts or plates which form cells. The struts or plates are constructed from a variety of metals, polymers, ceramics, and wood products. Cellular materials are often used in impact limiters for shipping containers to protect the contents from accidental impact events. These materials exhibit a variety of complex behavior when subjected to crushing loads. This research focuses on the development of continuum representations of cellular solids that can be used in the finite element analysis of shipping container accidents. A significant portion of this work is the development of a new methodology to relate localized deformations to appropriate constitutive descriptions. This methodology provides the insight needed to select constitutive descriptions for cellular solids that capture the localized deformations that are observed experimentally. Constitutive relations are developed for two different cellular materials, aluminum honeycomb and polyurethane foam. These constitutive relations are based on plasticity and continuum damage theories. Plasticity is used to describe the permanent deformation exhibited by both aluminum honeycomb and polyurethane foam. Continuum damage is needed to capture the change in elastic parameters due to cracking of the polyurethane cell wall materials. The new constitutive description of polyurethane foam is implemented in both static and dynamic finite element codes, and analytical and numerical predictions are compared with available experimental data.

  11. Continuum representations of cellular solids

    SciTech Connect

    Neilsen, M.K.

    1993-09-01

    Cellular materials consist of interconnected struts or plates which form cells. The struts or plates are constructed from a variety of metals, polymers, ceramics and wood products. Cellular materials are often used in impact limiters for shipping containers to protect the contents from accidental impact events. These materials exhibit a variety of complex behavior when subjected to crushing loads. This research focuses on the development of continuum representations of cellular solids that can be used in the finite element analysis of shipping container accidents. A significant portion of this work is the development of a new methodology to relate localized deformations to appropriate constitutive descriptions. This methodology provides the insight needed to select constitutive descriptions for cellular solids that capture the localized deformations that are observed experimentally. Constitutive relations are developed for two different cellular materials, aluminum honeycomb and polyurethane foam. These constitutive relations are based on plasticity and continuum damage theories. Plasticity is used to describe the permanent deformation exhibited by both aluminum honeycomb and polyurethane foam. Continuum damage is needed to capture the change in elastic parameters due to cracking of the polyurethane cell wall materials. The new constitutive description of polyurethane foam is implemented in both static and dynamic finite element codes, and analytical and numerical predictions are compared with available experimental data.

  12. Assessment of the intensity-duration-frequency (IDF) curves for storms in Peninsular Malaysia based on the generalized extreme value distribution

    NASA Astrophysics Data System (ADS)

    Mohd Ariff, Noratiqah; Jemain, Abdul Aziz; Wan Zin, Wan Zawiah

    2013-04-01

    Rainfall characteristics can be analyzed by using storm events with storms representing actual rainfall events instead of rainfall amounts in fixed time frames. One of the most commonly used methods in rainfall analysis is the construction of intensity-duration-frequency (IDF) curves. IDF curves help in designing hydraulic structures by providing a mathematical relationship between storm intensity, duration and return period. In Peninsular Malaysia, these curves are often built using the generalized extreme value (GEV) distribution to represent annual maximum storm intensity. The mathematical formula for the curves is usually taken from either known empirical equations or from quantile functions of probability distributions. However, there is no research which compares and analyzes the differences between the curves obtained for storms in Peninsular Malaysia based on the empirical and quantile functions. Thus, the aim of this study is to build IDF curves for storms in Peninsular Malaysia using typical empirical equations and the quantile function of the GEV distribution. Then, the analysis of differences is performed on the curves obtained from both approaches. The analysis consists of the coefficient of variation of root mean square error mean percentage difference and the coefficient of determination, R2. The analysis shows small differences between the curves based on the empirical equations and those obtained using the quantile function of GEV distribution. According to these results, it can be concluded that the simple empirical equations are sufficient in constructing IDF curves based on GEV distribution for storms in Peninsular Malaysia.

  13. A continuum framework for mechanics of fractal materials I: from fractional space to continuum with fractal metric

    NASA Astrophysics Data System (ADS)

    Balankin, Alexander S.

    2015-04-01

    This paper is devoted to the mechanics of fractally heterogeneous media. A model of fractal continuum with a fractional number of spatial degrees of freedom and a fractal metric is suggested. The Jacobian matrix of the fractal continuum deformation is defined and the kinematics of deformations is elucidated. The symmetry of the Cauchy stress tensor for continua with the fractal metric is established. A homogenization framework accounting for the connectivity, topological, and metric properties of fractal domains in heterogeneous materials is developed. The mapping of mechanical problems for fractal media into the corresponding problems for the fractal continuum is discussed. Stress and strain distributions in elastic fractal bars are analyzed. An approach to fractal bar optimization is proposed. Some features of acoustic wave propagation and localization in fractal media are briefly highlighted.

  14. Overview spectra and axial distribution of spectral line intensities in a high-current vacuum arc with CuCr electrodes

    SciTech Connect

    Lisnyak, M.; Pipa, A. V.; Gorchakov, S. E-mail: weltmann@inp-greifswald.de; Iseni, S.; Franke, St.; Khapour, A.; Methling, R.; Weltmann, K.-D. E-mail: weltmann@inp-greifswald.de

    2015-09-28

    Spectroscopic investigations of free-burning vacuum arcs in diffuse mode with CuCr electrodes are presented. The experimental conditions of the investigated arc correspond to the typical system for vacuum circuit breakers. Spectra of six species Cu I, Cu II, Cu III, Cr I, Cr II, and Cr III have been analyzed in the wavelength range 350–810 nm. The axial intensity distributions were found to be strongly dependent on the ionization stage of radiating species. Emission distributions of Cr II and Cu II can be distinguished as well as the distributions of Cr III and Cu III. Information on the axial distribution was used to identify the spectra and for identification of overlapping spectral lines. The overview spectra and some spectral windows recorded with high resolution are presented. Analysis of axial distributions of emitted light, which originates from different ionization states, is presented and discussed.

  15. Distribution patterns and sources of metals and PAHs in an intensely urbanized area: The Acerra-Pomigliano-Marigliano conurbation (Italy)

    NASA Astrophysics Data System (ADS)

    Albanese, Stefano; Lima, Annamaria; Rezza, Carmela; Ferullo, Giampiero; De Vivo, Benedetto; Chen, Wei; Qi, Shihua

    2014-05-01

    agricultural intensive land use. PAHs distribution pattern showed anomalous values across the whole study area. Especially, Benzo[a]pyrene values exceeds the trigger limits established by the Italian Environmental law (D.Lgs. 152/2006) in most of the analyzed soils and the diagnostic ratios calculated among several PAHs compounds suggested that the biomass burning in the rural sector of the study area could be a relevant source of pollution. The palm oil fuelled power plant in the northern sector of Acerra could not be excluded as a source of PAHs in the environment. [1] Albanese et al (2007) JGE 93, 21-34. [2] Cicchella et al (2008) GEEA 8 (1), 19-29. [3] De Vivo et al (2006) Aracne Editrice, Roma. 324 pp.

  16. [Distribution and appropriateness of hospital admissions, resource utilization in the Italian intensive cardiac care units. The BLITZ-3 study].

    PubMed

    Visconti, Luigi Oltrona; Scorcu, Giampaolo; Cassin, Matteo; Casella, Gianni; Chinaglia, Alessandra; Conte, Maria Rosa; Fradella, Giuseppe; Lucci, Donata; Maggioni, Aldo Pietro; Pirelli, Salvatore; Chiarella, Francesco

    2011-01-01

    The BLITZ-3 study prospectively evaluated the epidemiology of hospital admissions, the patterns of care and the most important comorbidities in intensive cardiac care unit (ICCU) patients. Distribution and level of appropriateness of hospital admissions in relation to type of ICCU were analyzed (type A, 32%, without cardiac cath lab or cardiac surgery; type B, 49%, with cath lab; type C, 19%, with both cath lab and cardiac surgery). The caseload was estimated on the basis of different levels of mortality risk during the ICCU stay: high (>5.1%), intermediate (0.7-5.1%), low (< or = 0.7%). A total of 6986 consecutive patients admitted to 332 ICCUs were enrolled. A median number of 19 patients (interquartile range 15-26) was admitted to each center during the 14 days of enrollment; 28% of the ICCUs admitted more than 25 patients, 48% between 15 and 25, and 24% less than 15. A higher number of type A ICCUs admitted less than 15 patients (p<0.0001), whereas a higher number of type C ICCUs admitted more than 25 patients (p<0.0001). Hospital admissions for ST-elevation myocardial infarction occurred more frequently in type B or C ICCUs (p<0.0001), whereas hospital admission for heart failure mostly occurred in type A ICCUs (p<0.0001). The number of patients not undergoing reperfusion (p<0.0001) or treated with thrombolytic therapy (p<0.0001) was higher in the type A ICCUs. Coronary revascularization with primary percutaneous coronary intervention was performed more frequently in type B and C ICCUs (p<0.0001). Similarly, patients hospitalized for acute coronary syndrome underwent coronary angiography (p<0.0001) and percutaneous coronary intervention more frequently in type B and C ICCUs (p<0.0001). Prevalence of low-risk rather than intermediate- or high-risk patients was higher in type A ICCUs (p<0.05), and prevalence of high- or intermediate-risk patients was higher in type C ICCUs (p<0.05). The results of the BLITZ-3 study should lead the Italian cardiological community

  17. Formation of the thermal infrared continuum in solar flares

    NASA Astrophysics Data System (ADS)

    Simões, Paulo J. A.; Kerr, Graham S.; Fletcher, Lyndsay; Hudson, Hugh S.; Giménez de Castro, C. Guillermo; Penn, Matt

    2017-09-01

    Aims: Observations of the Sun with the Atacama Large Millimeter Array have now started, and the thermal infrared will regularly be accessible from the NSF's Daniel K. Inouye Solar Telescope. Motivated by the prospect of these new data, and by recent flare observations in the mid infrared, we set out here to model and understand the source of the infrared continuum in flares, and to explore its diagnostic capability for the physical conditions in the flare atmosphere. Methods: We use the one-dimensional (1D) radiation hydrodynamics code RADYN to calculate mid-infrared continuum emission from model atmospheres undergoing sudden deposition of energy by non-thermal electrons. Results: We identify and characterise the main continuum thermal emission processes relevant to flare intensity enhancement in the mid- to far-infrared (2-200 μm) spectral range as free-free emission on neutrals and ions. We find that the infrared intensity evolution tracks the energy input to within a second, albeit with a lingering intensity enhancement, and provides a very direct indication of the evolution of the atmospheric ionisation. The prediction of highly impulsive emission means that, on these timescales, the atmospheric hydrodynamics need not be considered in analysing the mid-IR signatures.

  18. Analogies between continuum dislocation theory, continuum mechanics and fluid mechanics

    NASA Astrophysics Data System (ADS)

    Silbermann, C. B.; Ihlemann, J.

    2017-03-01

    Continuum Dislocation Theory (CDT) relates gradients of plastic deformation in crystals with the presence of geometrically necessary dislocations. Interestingly, CDT shows striking analogies to other branches of continuum mechanics. The present contribution demonstrates this on two essential kinematical quantities which reflect tensorial dislocation properties: the (resultant) Burgers vector and the dislocation density tensor. First, the limiting process for the (resultant) Burgers vector from an integral to a local quantity is performed analogously to the limiting process from the force vector to the traction vector. By evaluating the balance of forces on a tetrahedral volume element, Cauchy found his famous formula relating traction vector and stress tensor. It is shown how this procedure may be adopted to a continuously dislocated tetrahedron. Here, the conservation of Burger’s vector implicates the introduction of the dislocation density tensor. Second, analogies between the plastic flow of a continuously dislocated solid and the liquid flow of a fluid are highlighted: the resultant Burgers vector of a dislocation ensemble plays a similar role as the (resultant) circulation of a vortex tube. Moreover, both vortices within flowing fluids and dislocations within deforming solids induce discontinuities in the velocity field and the plastic distortion field, respectively. Beyond the analogies, some peculiar properties of the dislocation density tensor are presented as well.

  19. Space shuttle ram glow: Implication of NO2 recombination continuum

    NASA Technical Reports Server (NTRS)

    Swenson, G. R.; Mende, S. B.; Clifton, S.

    1985-01-01

    The ram glow data gathered to data from imaging experiments on space shuttle suggest the glow is a continuum (within 34 angstrom resolution); the continuum shape is such that the peak is near 7000 angstroms decreasing to the blue and red, and the average molecular travel leading to emission after leaving the surface is 20 cm (assuming isotropic scattering from the surface). Emission continuum is rare in molecular systems but the measured spectrum does resemble the laboratory spectrum of NO2 (B) recombination continuum. The thickness of the observed emission is consistent with the NO2 hypothesis given an exit velocity of approx. 2.5 km/sec (1.3 eV) which leaves approx. 3.7 eV of ramming OI energy available for unbonding the recombined NO2 from the surface. The NO2 is formed in a 3-body recombination of OI + NO + m = NO2 + m where OI originates from the atmosphere and NO is chemically formed on the surface from atmospheric NI and OI. The spacecraft surface then acts as the n for the reaction: Evidence exists from orbital mass spectrometer data that the NO and NO2 chemistry described in this process does occur on surfaces of spectrometer orifices in orbit. Surface temperature effects are likely a factor in the NO sticking efficiency and, therefore, glow intensities.

  20. Space shuttle Ram glow: Implication of NO2 recombination continuum

    NASA Astrophysics Data System (ADS)

    Swenson, G. R.; Mende, S. B.; Clifton, S.

    1985-09-01

    The ram glow data gathered to data from imaging experiments on space shuttle suggest the glow is a continuum (within 34 angstrom resolution); the continuum shape is such that the peak is near 7000 angstroms decreasing to the blue and red, and the average molecular travel leading to emission after leaving the surface is 20 cm (assuming isotropic scattering from the surface). Emission continuum is rare in molecular systems but the measured spectrum does resemble the laboratory spectrum of NO2 (B) recombination continuum. The thickness of the observed emission is consistent with the NO2 hypothesis given an exit velocity of approx. 2.5 km/sec (1.3 eV) which leaves approx. 3.7 eV of ramming OI energy available for unbonding the recombined NO2 from the surface. The NO2 is formed in a 3-body recombination of OI + NO + m = NO2 + m where OI originates from the atmosphere and NO is chemically formed on the surface from atmospheric NI and OI. The spacecraft surface then acts as the n for the reaction: Evidence exists from orbital mass spectrometer data that the NO and NO2 chemistry described in this process does occur on surfaces of spectrometer orifices in orbit. Surface temperature effects are likely a factor in the NO sticking efficiency and, therefore, glow intensities.

  1. Instrumental intensity distribution for the Hector Mine, California, and the Chi-Chi, Taiwan, earthquakes: Comparison of two methods

    USGS Publications Warehouse

    Sokolov, V.; Wald, D.J.

    2002-01-01

    We compare two methods of seismic-intensity estimation from ground-motion records for the two recent strong earthquakes: the 1999 (M 7.1) Hector Mine, California, and the 1999 (M 7.6) Chi-Chi, Taiwan. The first technique utilizes the peak ground acceleration (PGA) and velocity (PGV), and it is used for rapid generation of the instrumental intensity map in California. The other method is based on the revised relationships between intensity and Fourier amplitude spectrum (FAS). The results of using the methods are compared with independently observed data and between the estimations from the records. For the case of the Hector Mine earthquake, the calculated intensities in general agree with the observed values. For the case of the Chi-Chi earthquake, the areas of maximum calculated intensity correspond to the areas of the greatest damage and highest number of fatalities. However, the FAS method producees higher-intensity values than those of the peak amplitude method. The specific features of ground-motion excitation during the large, shallow, thrust earthquake may be considered a reason for the discrepancy. The use of PGA and PGV is simple; however, the use of FAS provides a natural consideration of site amplification by means of generalized or site-specific spectral ratios. Because the calculation of seismic-intensity maps requires rapid processing of data from a large network, it is very practical to generate a "first-order" map from the recorded peak motions. Then, a "second-order" map may be compiled using an amplitude-spectra method on the basis of available records and numerical modeling of the site-dependent spectra for the regions of sparse station spacing.

  2. The High-energy Continuum Emission of the Gamma-Ray Blazar PKS 0528+134

    NASA Technical Reports Server (NTRS)

    Sambruna, Rita M.; Urry, C. Megan; Maraschi, L.; Ghisellini, G.; Mukherjee, R.; Pesce, Joseph E.; Wagner, S. J.; Wehrle, A. E.; Hartman, R. C.; Lin, Y. C.; VonMintigny, C.

    1997-01-01

    We present Advanced Satellite for Cosmology and Astrophysics (ASCA) observations of the gamma-ray blazar PKS 0528 + 134, obtained at two separate epochs in 1994 August and 1995 March. These data represent the first measurement of the X-ray continuum emission of this source in the medium-hard X-ray band. Both ASCA spectra are consistent with a single power law with photon index GAMMA approx. = 1.7-1.8 and column density N(sub H) approx. = 5 x 10(exp 21)/ sq cm, higher than Galactic. The X-ray flux increased by a factor of 4 in approx. 7 months without appreciable change of the spectral shape. During the lower state of 1994 August, PKS 0528 + 134 was observed simultaneously in the optical, X-rays, and at gamma-ray energies with Energetic Gamma Ray Experiment Telescope (EGRET). The gamma-ray intensity is the faintest detected thus far in the source, with a steep spectrum (GAMMA approx. = 2.7). The extrapolation of the X-ray continuum to the gamma-ray range requires a sharp spectral break at approx. 10(exp 22) Hz. We discuss the radio through gamma-ray spectral energy distribution of PKS 0528 + 134, comparing the low state of 1994 August with the flare state of 1993 March. We show that in PKS 0528 + 134, a non-negligible contribution from the external radiation field is present and that, although synchrotron self-Compton scenarios cannot be ruled out, inverse Compton upscattering of thermal seed photons may be the dominant cooling process for the production of the high-energy continuum in this blazar.

  3. The High-Energy Continuum Emission of the Gamma-Ray Blazar PKS 0528+134

    NASA Technical Reports Server (NTRS)

    Sambruna, Rita M.; Urry, C. Megan; Maraschi, L.; Ghisellini, G.; Mukherjee, R.; Pesce, Joseph E.; Wagner, S. J.; Wehrle, A. E.; Hartman, R. C.; Lin, Y. C.

    1997-01-01

    We present Advanced Satellite for Cosmology and Astrophysics (ASCA) observations of the gamma-ray blazar PKS 0528 + 134, obtained at two separate epochs in 1994 August and 1995 March. These data represent the first measurement of the X-ray continuum emission of this source in the medium-hard X-ray band. Both ASCA spectra are consistent with a single power law with photon index GAMMA approximate 1.7-1.8 and column density N(sub H) approximately 5 x 10(exp 21) /sq cm, higher than Galactic. The X-ray flux increased by a factor of 4 in approximately 7 months without appreciable change of the spectral shape. During the lower state of 1994 August, PKS 0528 + 134 was observed simultaneously in the optical, X-rays, and at gamma-ray energies with EGRET. The gamma-ray intensity is the faintest detected thus far in the source, with a steep spectrum (GAMMA approximately 2.7). The extrapolation of the X-ray continuum to the gamma-ray range requires a sharp spectral break at approximately 10(exp 22) Hz. We discuss the radio through gamma-ray spectral energy distribution of PKS 0528 + 134, comparing the low state of 1994 August with the flare state of 1993 March. We show that in PKS 0528 + 134, a non-negligible contribution from the external radiation field is present and that, although synchrotron self-Compton scenarios cannot be ruled out, inverse Compton upscattering of thermal seed photons may be the dominant cooling process for the production of the high-energy continuum in this blazar.

  4. Continuum Theory of Retroviral Capsids

    NASA Astrophysics Data System (ADS)

    Nguyen, T. T.; Bruinsma, R. F.; Gelbart, W. M.

    2006-02-01

    We present a self-assembly phase diagram for the shape of retroviral capsids, based on continuum elasticity theory. The spontaneous curvature of the capsid proteins drives a weakly first-order transition from spherical to spherocylindrical shapes. The conical capsid shape which characterizes the HIV-1 retrovirus is never stable under unconstrained energy minimization. Only under conditions of fixed volume and/or fixed spanning length can the conical shape be a minimum energy structure. Our results indicate that, unlike the capsids of small viruses, retrovirus capsids are not uniquely determined by the molecular structure of the constituent proteins but depend in an essential way on physical constraints present during assembly.

  5. Continuum modeling of myxobacteria clustering

    NASA Astrophysics Data System (ADS)

    Harvey, Cameron W.; Alber, Mark; Tsimring, Lev S.; Aranson, Igor S.

    2013-03-01

    In this paper we develop a continuum theory of clustering in ensembles of self-propelled inelastically colliding rods with applications to collective dynamics of common gliding bacteria Myxococcus xanthus. A multi-phase hydrodynamic model that couples densities of oriented and isotropic phases is described. This model is used for the analysis of an instability that leads to spontaneous formation of directionally moving dense clusters within initially dilute isotropic ‘gas’ of myxobacteria. Numerical simulations of this model confirm the existence of stationary dense moving clusters and also elucidate the properties of their collisions. The results are shown to be in a qualitative agreement with experiments.

  6. Disease management: a continuum approach.

    PubMed

    Harvey, N; DePue, D M

    1997-06-01

    Disease management is a comprehensive, integrated approach to managing the health of populations through the use of disease-specific standards and protocols and population segmentation. It has been increasing in popularity among integrated delivery systems (IDSs) and payers alike as a way to respond to competitive pressures and to shift care delivery from inpatient to alternative care sites. To successfully implement disease-management programs, IDSs must develop an organizational mind-set that stresses information-driven, evidence-based standards of care that are adhered to across a tightly integrated continuum of care.

  7. Collective excitations in the continuum

    SciTech Connect

    Dussel, G. G.; Betan, R. Id; Liotta, R. J.; Vertse, T.

    2009-12-15

    Pairing (particle-particle) giant resonances are analyzed within a shell-model formalism in the complex energy plane with the aim of understanding why they have not been observed so far. A comparison is made with the equivalent particle-hole mode by applying the formalism to the analysis of the well-understood particle-hole giant resonance. It is found that because of the proper treatment of the continuum intrinsic to the formalism, giant pairing resonances lie much higher than previously predicted and that some of them may be too wide to be observed, whereas others are meaningful excitations. For these, new experimental searches are proposed.

  8. Intensity-Stabilized Fast-Scanned Direct Absorption Spectroscopy Instrumentation Based on a Distributed Feedback Laser with Detection Sensitivity down to 4 × 10−6

    PubMed Central

    Zhao, Gang; Tan, Wei; Jia, Mengyuan; Hou, Jiajuan; Ma, Weiguang; Dong, Lei; Zhang, Lei; Feng, Xiaoxia; Wu, Xuechun; Yin, Wangbao; Xiao, Liantuan; Axner, Ove; Jia, Suotang

    2016-01-01

    A novel, intensity-stabilized, fast-scanned, direct absorption spectroscopy (IS-FS-DAS) instrumentation, based on a distributed feedback (DFB) diode laser, is developed. A fiber-coupled polarization rotator and a fiber-coupled polarizer are used to stabilize the intensity of the laser, which significantly reduces its relative intensity noise (RIN). The influence of white noise is reduced by fast scanning over the spectral feature (at 1 kHz), followed by averaging. By combining these two noise-reducing techniques, it is demonstrated that direct absorption spectroscopy (DAS) can be swiftly performed down to a limit of detection (LOD) (1σ) of 4 × 10−6, which opens up a number of new applications. PMID:27657082

  9. GAS EXCHANGE OF ALGAE. I. EFFECTS OF TIME, LIGHT INTENSITY, AND SPECTRAL-ENERGY DISTRIBUTION ON THE PHOTOSYNTHETIC QUOTIENT OF CHLORELLA PYRENOIDOSA.

    PubMed

    AMMANN, E C; LYNCH, V H

    1965-07-01

    Continuously growing cultures of Chlorella pyrenoidosa Starr 252, operating at constant density and under constant environmental conditions, produced uniform photosynthetic quotient (PQ = CO(2)/O(2)) and O(2) values during 6 months of observations. The PQ for the entire study was 0.90 +/- 0.024. The PQ remained constant over a threefold light-intensity change and a threefold change in O(2) production (0.90 +/- 0.019). At low light intensities, when the rate of respiration approached the rate of photosynthesis, the PQ became extremely variable. Six lamps of widely different spectral-energy distribution produced no significant change in the PQ (0.90 +/- 0.025). Oxygen production was directly related to the number of quanta available, irrespective of spectral-energy distribution. Such dependability in producing uniform PQ and O(2) values warrants a consideration of algae to maintain a constant gas environment for submarine or spaceship use.

  10. Generalized Courant-Snyder Theory and Kapchinskij-Vladimirskij Distribution For High-intensity Beams In A Coupled Transverse Focusing Lattice

    SciTech Connect

    Hong QIn, Ronald Davidson

    2011-07-18

    The Courant-Snyder (CS) theory and the Kapchinskij-Vladimirskij (KV) distribution for high-intensity beams in a uncoupled focusing lattice are generalized to the case of coupled transverse dynamics. The envelope function is generalized to an envelope matrix, and the envelope equation becomes a matrix envelope equation with matrix operations that are non-commutative. In an uncoupled lattice, the KV distribution function, first analyzed in 1959, is the only known exact solution of the nonlinear Vlasov-Maxwell equations for high-intensity beams including self-fields in a self-consistent manner. The KV solution is generalized to high-intensity beams in a coupled transverse lattice using the generalized CS invariant. This solution projects to a rotating, pulsating elliptical beam in transverse configuration space. The fully self-consistent solution reduces the nonlinear Vlasov-Maxwell equations to a nonlinear matrix ordinary differential equation for the envelope matrix, which determines the geometry of the pulsating and rotating beam ellipse. These results provide us with a new theoretical tool to investigate the dynamics of high-intensity beams in a coupled transverse lattice. A strongly coupled lattice, a so-called N-rolling lattice, is studied as an example. It is found that strong coupling does not deteriorate the beam quality. Instead, the coupling induces beam rotation, and reduces beam pulsation.

  11. Generalized Courant-Snyder theory and Kapchinskij-Vladimirskij distribution for high-intensity beams in a coupled transverse focusing lattice

    SciTech Connect

    Qin Hong; Davidson, Ronald C.

    2011-05-15

    The Courant-Snyder (CS) theory and the Kapchinskij-Vladimirskij (KV) distribution for high-intensity beams in an uncoupled focusing lattice are generalized to the case of coupled transverse dynamics. The envelope function is generalized to an envelope matrix, and the envelope equation becomes a matrix envelope equation with matrix operations that are noncommutative. In an uncoupled lattice, the KV distribution function, first analyzed in 1959, is the only known exact solution of the nonlinear Vlasov-Maxwell equations for high-intensity beams including self-fields in a self-consistent manner. The KV solution is generalized to high-intensity beams in a coupled transverse lattice using the generalized CS invariant. This solution projects to a rotating, pulsating elliptical beam in transverse configuration space. The fully self-consistent solution reduces the nonlinear Vlasov-Maxwell equations to a nonlinear matrix ordinary differential equation for the envelope matrix, which determines the geometry of the pulsating and rotating beam ellipse. These results provide us with a new theoretical tool to investigate the dynamics of high-intensity beams in a coupled transverse lattice. A strongly coupled lattice, a so-called N-rolling lattice, is studied as an example. It is found that strong coupling does not deteriorate the beam quality. Instead, the coupling induces beam rotation and reduces beam pulsation.

  12. Nonlocal models in continuum mechanics

    SciTech Connect

    Johnson, N.L.; Phan-Thien, N.

    1993-09-01

    The recent appearance of nonlocal methods is examined in the light of traditional continuum mechanics. A comparison of nonlocal approaches in the fields of solid and fluid mechanics reveals that no consistent definition of a nonlocal theory has been used. We suggest a definition based on the violation of the principle of local action in continuum mechanics. From the consideration of the implications of a nonlocal theory based on this definition, we conclude that constitutive relations with nonlocal terms can confuse the traditional separation of the roles between conservation laws and constitutive relations. The diversity of motivations for the nonlocal approaches are presented, resulting primarily from deficiencies in numerical solutions to practical problems. To illustrate these concepts, the history of nonlocal terms in the field of viscoelastic fluids is reviewed. A specific example of a viscoelastic constitutive relation that contains a stress diffusion term is applied to a simple shear flow and found not to be a physical description of any known fluid. We conclude by listing questions that should be asked of nonlocal approaches.

  13. Nuclear rotation in the continuum

    NASA Astrophysics Data System (ADS)

    Fossez, K.; Nazarewicz, W.; Jaganathen, Y.; Michel, N.; Płoszajczak, M.

    2016-01-01

    Background: Atomic nuclei often exhibit collective rotational-like behavior in highly excited states, well above the particle emission threshold. What determines the existence of collective motion in the continuum region is not fully understood. Purpose: In this work, by studying the collective rotation of the positive-parity deformed configurations of the one-neutron halo nucleus 11Be, we assess different mechanisms that stabilize collective behavior beyond the limits of particle stability. Method: To solve a particle-plus-core problem, we employ a nonadiabatic coupled-channel formalism and the Berggren single-particle ensemble, which explicitly contains bound states, narrow resonances, and the scattering continuum. We study the valence-neutron density in the intrinsic rotor frame to assess the validity of the adiabatic approach as the excitation energy increases. Results: We demonstrate that collective rotation of the ground band of 11Be is stabilized by (i) the fact that the ℓ =0 one-neutron decay channel is closed, and (ii) the angular momentum alignment, which increases the parentage of high-ℓ components at high spins; both effects act in concert to decrease decay widths of ground-state band members. This is not the case for higher-lying states of 11Be, where the ℓ =0 neutron-decay channel is open and often dominates. Conclusion: We demonstrate that long-lived collective states can exist at high excitation energy in weakly bound neutron drip-line nuclei such as 11Be.

  14. The infrared continuum spectrum of x ray illuminated molecular gas

    NASA Technical Reports Server (NTRS)

    Voit, G. Mark

    1990-01-01

    In starburst galaxies, active galaxies, and the mysterious ultraluminous infrared galaxies, x rays are likely to interact with molecular gas and dust, thereby inducing infrared emission. X ray heated thermal dust will emit the IR continuum, and x ray photoelectrons will excite an IR emission-line spectrum. Here, researchers model the IR continuum emission characteristic of some selected x ray spectral fluxes, in particular the x ray bremsstrahlung characteristic of supernova and stellar wind bubble shocks in dense media and the power law spectra characteristic of active galactic nuclei. These models are part of a larger project to determine the complete IR spectra, lines plus continuum, of x ray sources embedded in molecular gas. They modeled the thermal emission from grains by calculating a grain temperature/size/composition distribution function, f(T,a,Comp.), which accounts for temperature fluctuations by averaging over all grain thermal histories. In determining the grain thermal distribution, researchers account for both direct grain heating (by x ray absorption and subsequent electron energy deposition) and indirect grain heating (by absorption of the UV emission stimulated by non-thermal photo- and Auger electrons in the gas phase). We let the grain size distribution be proportional to a(exp -3.5), and they consider two types of grain composition: graphites, which we assume to be pure carbon, and silicates, which contain all other depleted heavy elements. They derive the grain composition distribution function from solar abundances and interstellar depletion data.

  15. Levels and patterns of objectively-measured physical activity volume and intensity distribution in UK adolescents: the ROOTS study.

    PubMed

    Collings, Paul J; Wijndaele, Katrien; Corder, Kirsten; Westgate, Kate; Ridgway, Charlotte L; Dunn, Valerie; Goodyer, Ian; Ekelund, Ulf; Brage, Soren

    2014-02-24

    Few studies have quantified levels of habitual physical activity across the entire intensity range. We aimed to describe variability in total and intensity-specific physical activity levels in UK adolescents across gender, socio-demographic, temporal and body composition strata. Physical activity energy expenditure and minutes per day (min/d) spent sedentary and in light, moderate, and vigorous intensity physical activity were assessed in 825 adolescents from the ROOTS study (43.5% boys; mean age 15.0 ± 0.30 years), by 4 days of individually calibrated combined heart rate and movement sensing. Measurement days were classified as weekday or weekend and according to the three school terms: summer (April-July), autumn (September-December), and spring (January-March). Gender and age were self-reported and area-level SES determined by postcode data. Body composition was measured by anthropometry and bio-electrical impedance. Variability in physical activity and sedentary time was analysed by linear multilevel modelling, and logistic multilevel regression was used to determine factors associated with physical inactivity (<60 min moderate-to-vigorous intensity physical activity/d). During awake hours (15.8 ± 0.9 hrs/d), adolescents primarily engaged in light intensity physical activity (517 min/d) and sedentary time (364 min/d). Boys were consistently more physically active and less sedentary than girls, but gender differences were smaller at weekends, as activity levels in boys dropped more markedly when transitioning from weekday to weekend. Boys were more sedentary on both weekend days compared to during the week, whereas girls were more sedentary on Sunday but less sedentary on Saturday. In both genders light intensity physical activity was lower in spring, while moderate physical activity was lower in autumn and spring terms, compared to the summer term; sedentary time was also higher in spring than summer term. Adolescents with higher fatness engaged in

  16. A Threshold Continuum for Aeolian Sand Transport

    NASA Astrophysics Data System (ADS)

    Swann, C.; Ewing, R. C.; Sherman, D. J.

    2015-12-01

    The threshold of motion for aeolian sand transport marks the initial entrainment of sand particles by the force of the wind. This is typically defined and modeled as a singular wind speed for a given grain size and is based on field and laboratory experimental data. However, the definition of threshold varies significantly between these empirical models, largely because the definition is based on visual-observations of initial grain movement. For example, in his seminal experiments, Bagnold defined threshold of motion when he observed that 100% of the bed was in motion. Others have used 50% and lesser values. Differences in threshold models, in turn, result is large errors in predicting the fluxes associated with sand and dust transport. Here we use a wind tunnel and novel sediment trap to capture the fractions of sand in creep, reptation and saltation at Earth and Mars pressures and show that the threshold of motion for aeolian sand transport is best defined as a continuum in which grains progress through stages defined by the proportion of grains in creep and saltation. We propose the use of scale dependent thresholds modeled by distinct probability distribution functions that differentiate the threshold based on micro to macro scale applications. For example, a geologic timescale application corresponds to a threshold when 100% of the bed in motion whereas a sub-second application corresponds to a threshold when a single particle is set in motion. We provide quantitative measurements (number and mode of particle movement) corresponding to visual observations, percent of bed in motion and degrees of transport intermittency for Earth and Mars. Understanding transport as a continuum provides a basis for revaluating sand transport thresholds on Earth, Mars and Titan.

  17. Breakdown of Continuum Fracture Mechanics at the Nanoscale

    PubMed Central

    Shimada, Takahiro; Ouchi, Kenji; Chihara, Yuu; Kitamura, Takayuki

    2015-01-01

    Materials fail by the nucleation and propagation of a crack, the critical condition of which is quantitatively described by fracture mechanics that uses an intensity of singular stress field characteristically formed near the crack-tip. However, the continuum assumption basing fracture mechanics obscures the prediction of failure of materials at the nanoscale due to discreteness of atoms. Here, we demonstrate the ultimate dimensional limit of fracture mechanics at the nanoscale, where only a small number of atoms are included in a singular field of continuum stress formed near a crack tip. Surprisingly, a singular stress field of only several nanometers still governs fracture as successfully as that at the macroscale, whereas both the stress intensity factor and the energy release rate fail to describe fracture below a critically confined singular field of 2–3 nm, i.e., breakdown of fracture mechanics within the framework of the continuum theory. We further propose an energy-based theory that explicitly accounts for the discrete nature of atoms, and demonstrate that our theory not only successfully describes fracture even below the critical size but also seamlessly connects the atomic to macroscales. It thus provides a more universal fracture criterion, and novel atomistic insights into fracture. PMID:25716684

  18. Haro 11: Where is the Lyman Continuum Source?

    NASA Astrophysics Data System (ADS)

    Keenan, Ryan P.; Oey, M. S.; Jaskot, Anne; James, Bethan

    2017-01-01

    Haro 11 is the best known source of Lyman continuum (LyC) emission in the local universe and is thought to be an analog of the early galaxies that drove cosmic reionization. The source of LyC emission within Haro 11 has not yet been identified, since the LyC detection is unresolved. To map the optically thin regions in this galaxy, we apply our technique of ionization parameter mapping, which uses continuum-subtracted, HST WFC3 and ACS narrowband images of [O III] and [O II] emission to construct ratio maps. These allow us to identify regions of the galaxy that are likely to be optically thin. Due to the importance of continuum subtraction for this technique, we also develop a new method for scaling the continuum images based on the mode of the pixel distribution. We find that a region extending from Haro 11 Knot A appears to be optically thin. Other regions of the galaxy have also been suggested as potential LyC sources, based on the presence of a ULX (Knot B) and Ly-alpha emission (Knot C). Our work now adds Knot A as a third candidate LyC source in this complex merger system. (This work was supported by NASA grant HST-GO-13702)

  19. 77 FR 45367 - Continuum of Care Homeless Assistance Grant Application; Continuum of Care Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-31

    ... URBAN DEVELOPMENT Continuum of Care Homeless Assistance Grant Application; Continuum of Care Application... and renewal funding. State and local governments, public housing authorities and nonprofit...: Colette Pollard., Reports Management Officer, QDAM, Department of Housing and Urban Development,...

  20. Continuum electromechanical modeling of protein-membrane interactions.

    PubMed

    Zhou, Y C; Lu, Benzhuo; Gorfe, Alemayehu A

    2010-10-01

    A continuum electromechanical model is proposed to describe the membrane curvature induced by electrostatic interactions in a solvated protein-membrane system. The model couples the macroscopic strain energy of membrane and the electrostatic solvation energy of the system, and equilibrium membrane deformation is obtained by minimizing the electroelastic energy functional with respect to the dielectric interface. The model is illustrated with the systems with increasing geometry complexity and captures the sensitivity of membrane curvature to the permanent and mobile charge distributions.

  1. Evidence for the significant role of sea surface temperature distributions over remote tropical oceans in tropical cyclone intensity

    NASA Astrophysics Data System (ADS)

    Hegde, Anitha Kumari; Kawamura, Ryuichi; Kawano, Tetsuya

    2016-07-01

    The role of remote ocean sea surface temperature (SST) in regulating tropical cyclone (TC) characteristics has been examined by performing numerical experiments with a regional scale model. Model simulations have been carried out to simulate typhoon Man-yi (July 2007), in our case study, under a range of SST conditions over the Indian Ocean and the South China Sea. The intensity and track of the cyclone have been systematically changed in sensitivity simulations of cool and warm SSTs over that region, following its peak phase. Warm oceans can substantially reduce the intensification of western North Pacific cyclones, whereas cool oceans can enhance their strength. This is intimately associated with the enhancement/weakening of the moisture supply through the moisture conveyor belt (MCB) in the lower troposphere, from the Indian Ocean and South China Sea into the vicinity of the cyclone center. When the MCB is interrupted over the South China Sea in warm SST occurrences, the large-scale transport of moisture into the cyclone system is significantly reduced, leading to the weakening of the cyclone intensity and to the eastward shift of its track. This study shows that changes in remote tropical ocean SST can also modulate TCs and thus can help in improving the forecasting of TC intensities and tracks.

  2. Temperature distributions measurement of high intensity focused ultrasound using a thin-film thermocouple array and estimation of thermal error caused by viscous heating.

    PubMed

    Matsuki, Kosuke; Narumi, Ryuta; Azuma, Takashi; Yoshinaka, Kiyoshi; Sasaki, Akira; Okita, Kohei; Takagi, Shu; Matsumoto, Yoichiro

    2013-01-01

    To improve the throughput of high intensity focused ultrasound (HIFU) treatment, we have considered a focus switching method at two points. For this method, it is necessary to evaluate the thermal distribution under exposure to ultrasound. The thermal distribution was measured using a prototype thin-film thermocouple array, which has the advantage of minimizing the influence of the thermocouple on the acoustic and temperature fields. Focus switching was employed to enlarge the area of temperature increase and evaluate the proposed evaluation parameters with respect to safety and uniformity. The results indicate that focus switching can effectively expand the thermal lesion while maintaining a steep thermal boundary. In addition, the influence caused by the thin-film thermocouple array was estimated experimentally. This thermocouple was demonstrated to be an effective tool for the measurement of temperature distributions induced by HIFU.

  3. Non-Maxwellian electron distributions in time-dependent simulations of low-Z materials illuminated by a high-intensity X-ray laser

    NASA Astrophysics Data System (ADS)

    de la Varga, Alberto G.; Velarde, Pedro; de Gaufridy, François; Portillo, David; Cotelo, Manuel; Barbas, Alfonso; González, Agustín; Zeitoun, Philippe

    2013-09-01

    The interaction of high intensity X-ray lasers with matter is modeled. A collisional-radiative time-dependent module is implemented to study radiation transport in matter from ultrashort and ultraintense X-ray bursts. Inverse bremsstrahlung absorption by free electrons, electron conduction or hydrodynamic effects are not considered. The collisional-radiative system is coupled with the electron distribution evolution treated with a Fokker-Planck approach with additional inelastic terms. The model includes spontaneous emission, resonant photoabsorption, collisional excitation and de-excitation, radiative recombination, photoionization, collisional ionization, three-body recombination, autoionization and dielectronic capture. It is found that for high densities, but still below solid, collisions play an important role and thermalization times are not short enough to ensure a thermal electron distribution. At these densities Maxwellian and non-Maxwellian electron distribution models yield substantial differences in collisional rates, modifying the atomic population dynamics.

  4. Continuum Fitting HST QSO Spectra

    NASA Technical Reports Server (NTRS)

    Tytler, David; Oliversen, Ronald J. (Technical Monitor)

    2002-01-01

    The Principal Component Analysis (PCA) method which we are using to fit and describe QSO spectra relies upon the fact that QSO continuum are generally very smooth and simple except for emission and absorption lines. To see this we need high signal-to-noise (S/N) spectra of QSOs at low redshift which have relatively few absorption lines in the Lyman-a forest. We need a large number of such spectra to use as the basis set for the PCA analysis which will find the set of principal component spectra which describe the QSO family as a whole. We have found that too few HST spectra have the required S/N and hence we need to supplement them with ground based spectra of QSOs at higher redshift. We have many such spectra and we have been working to make them suitable for this analysis. We have concentrated on this topic since 12/15/01.

  5. Bound states in the continuum

    NASA Astrophysics Data System (ADS)

    Hsu, Chia Wei; Zhen, Bo; Stone, A. Douglas; Joannopoulos, John D.; Soljačić, Marin

    2016-09-01

    Bound states in the continuum (BICs) are waves that remain localized even though they coexist with a continuous spectrum of radiating waves that can carry energy away. Their very existence defies conventional wisdom. Although BICs were first proposed in quantum mechanics, they are a general wave phenomenon and have since been identified in electromagnetic waves, acoustic waves in air, water waves and elastic waves in solids. These states have been studied in a wide range of material systems, such as piezoelectric materials, dielectric photonic crystals, optical waveguides and fibres, quantum dots, graphene and topological insulators. In this Review, we describe recent developments in this field with an emphasis on the physical mechanisms that lead to BICs across seemingly very different materials and types of waves. We also discuss experimental realizations, existing applications and directions for future work.

  6. Micropolar continuum in spatial description

    NASA Astrophysics Data System (ADS)

    Ivanova, Elena A.; Vilchevskaya, Elena N.

    2016-11-01

    Within the spatial description, it is customary to refer thermodynamic state quantities to an elementary volume fixed in space containing an ensemble of particles. During its evolution, the elementary volume is occupied by different particles, each having its own mass, tensor of inertia, angular and linear velocities. The aim of the present paper is to answer the question of how to determine the inertial and kinematic characteristics of the elementary volume. In order to model structural transformations due to the consolidation or defragmentation of particles or anisotropic changes, one should consider the fact that the tensor of inertia of the elementary volume may change. This means that an additional constitutive equation must be formulated. The paper suggests kinetic equations for the tensor of inertia of the elementary volume. It also discusses the specificity of the inelastic polar continuum description within the framework of the spatial description.

  7. Dementia: Continuum or Distinct Entity?

    PubMed Central

    Walters, Glenn D.

    2009-01-01

    The latent structure of dementia was examined in a group of 10,775 older adults with indicators derived from a neuropsychological test battery. Subjecting these data to taxometric analysis using mean above minus below a cut (MAMBAC), maximum covariance (MAXCOV), and latent mode factor analysis (L-Mode) produced results more consistent with dementia as a dimensional (lying along a continuum) than categorical (representing a distinct entity) construct. A second study conducted on a group of 2375 21-to-64-year olds produced similar results. These findings denote that dementia, as measured by deficits in episodic memory, attention/concentration, executive function, and language, differs quantitatively rather than qualitatively from the cognitive status of non-demented adults. The implications of these results for classification, assessment, etiology, and prevention are discussed. PMID:20677881

  8. Computational Methods in Continuum Mechanics

    DTIC Science & Technology

    1993-11-30

    ftruet11ft bwalch.Aq 0.4.oiqn 04ta tou.MtC’ gahimtc" n matod .nAfitang In@ data 01#04141. OAd co0noIDW~ng And tft@nq the ~OIWCI&Qn of 1,onjt~omt .nd~ml...AD-A27S 560 DTIC\\3\\Ul3 10 S ELECTE1 FEB 9 1994 I c I £ COMPUTATIONAL METHODS IN CONTINUUM MECHANICS By Bolindra N . Borah N.C. A&T State University...PAGE 0me No 0.704-0158 io (reorovtnq burden ’Of .t..i e’iortion of Information is estimted to ’Adoraw 1O4 .0 e~o- * n th.n I~c ot.. "o.vw.n. q

  9. The source location and beaming of terrestrial continuum radiation

    SciTech Connect

    Morgan, D.D.; Gurnett, D.A. )

    1991-06-01

    Plasma wave data from the spacecraft Dynamics Explorer 1 were used to study the source location and beaming of terrestrial continuum radiation. This study shows that the radiation usually is generated near the magnetic equator at radial distances ranging from 2.0 to 4.0 R{sub E}. The radiation is beamed outward in a broad beam directed along the magnetic equator with a beam width of about 100 {degrees}. The overall frequency of occurrence of continuum radiation was found to be 60% with a sharp increase near the midnight meridian, increasing the dawnward direction. Several case studies are presented to illustrated various characteristics of continuum radiation. The observed characteristics are then compared with the radio window model of Jones. Several characteristics not predicted by Jones' model are observed. These include large latitudinal asymmetries, an absence of a minimum in the occurrence and intensity at the equator, a tendency for higher frequency bands to come from larger and more diffuse source regions, and the emergence of several distinct beams from a single region. In particular the absence of a minimum in the occurrence and intensity at the equator and the emergence of beams of radiation at sharply distinct angles from one source region constitute evidence against the radio window model. Also, the basic equation for the beaming angle with respect to the magnetic equatorial plane is found to be a poor predictor of the observed beaming angle. The evidence against the radio window model is partially mitigated by the facts that the source of radiation is probably extended in space and frequency and that sometimes radiation from the Sun interferes with the direction finding. Overall, these observations imply that the radio window model does not fully explain the beaming pattern of continuum radiation.

  10. Simultaneous reconstruction of 3D refractive index, temperature, and intensity distribution of combustion flame by double computed tomography technologies based on spatial phase-shifting method

    NASA Astrophysics Data System (ADS)

    Guo, Zhenyan; Song, Yang; Yuan, Qun; Wulan, Tuya; Chen, Lei

    2017-06-01

    In this paper, a transient multi-parameter three-dimensional (3D) reconstruction method is proposed to diagnose and visualize a combustion flow field. Emission and transmission tomography based on spatial phase-shifted technology are combined to reconstruct, simultaneously, the various physical parameter distributions of a propane flame. Two cameras triggered by the internal trigger mode capture the projection information of the emission and moiré tomography, respectively. A two-step spatial phase-shifting method is applied to extract the phase distribution in the moiré fringes. By using the filtered back-projection algorithm, we reconstruct the 3D refractive-index distribution of the combustion flow field. Finally, the 3D temperature distribution of the flame is obtained from the refractive index distribution using the Gladstone-Dale equation. Meanwhile, the 3D intensity distribution is reconstructed based on the radiation projections from the emission tomography. Therefore, the structure and edge information of the propane flame are well visualized.

  11. Formation of a conical distribution and intense ion heating in the presence of hydrogen cyclotron waves. [in earth ionosphere

    NASA Technical Reports Server (NTRS)

    Okuda, H.; Ashour-Abdalla, M.

    1981-01-01

    In the considered investigation, it is assumed that the field aligned currents are responsible for producing electrostatic harmonic cyclotron waves (EHC). Using a one-dimensional simulation model in which the electron velocity distribution is maintained by a constant injection of the initial distribution, it is shown that, in contrast to earlier initial value simulations, EHC waves grow to a large amplitude, resulting in the formation of an anisotropic ion velocity distribution. Both the heating rate and the anisotropy are in reasonable agreement with the quasi-linear theory, taking into account the cyclotron resonance. The results show that the saturation is due to the combined effects of wave induced diffusion in an electron velocity space and the heating of ions perpendicularly. Both these effects reduce the growth rate.

  12. Formation of a conical distribution and intense ion heating in the presence of hydrogen cyclotron waves. [in earth ionosphere

    NASA Technical Reports Server (NTRS)

    Okuda, H.; Ashour-Abdalla, M.

    1981-01-01

    In the considered investigation, it is assumed that the field aligned currents are responsible for producing electrostatic harmonic cyclotron waves (EHC). Using a one-dimensional simulation model in which the electron velocity distribution is maintained by a constant injection of the initial distribution, it is shown that, in contrast to earlier initial value simulations, EHC waves grow to a large amplitude, resulting in the formation of an anisotropic ion velocity distribution. Both the heating rate and the anisotropy are in reasonable agreement with the quasi-linear theory, taking into account the cyclotron resonance. The results show that the saturation is due to the combined effects of wave induced diffusion in an electron velocity space and the heating of ions perpendicularly. Both these effects reduce the growth rate.

  13. Topographic distribution, frequency, and intensity dependence of stimulus-specific adaptation in the inferior colliculus of the rat.

    PubMed

    Duque, Daniel; Pérez-González, David; Ayala, Yaneri A; Palmer, Alan R; Malmierca, Manuel S

    2012-12-05

    The ability to detect unexpected sounds within the environment is an important function of the auditory system, as a rapid response may be required for the organism to survive. Previous studies found a decreased response to repetitive stimuli (standard), but an increased response to rare or less frequent sounds (deviant) in individual neurons in the inferior colliculus (IC) and at higher levels. This phenomenon, known as stimulus-specific adaptation (SSA) has been suggested to underpin change detection. Currently, it is not known how SSA varies within a single neuron receptive field, i.e., it is unclear whether SSA is a unique property of the neuron or a feature that is frequency and/or intensity dependent. In the present experiments, we used the common SSA index (CSI) to quantify and compare the degree of SSA under different stimulation conditions in the IC of the rat. We calculated the CSI at different intensities and frequencies for each individual IC neuron to map the neuronal CSI within the receptive field. Our data show that high SSA is biased toward the high-frequency and low-intensity regions of the receptive field. We also find that SSA is better represented in the earliest portions of the response, and there is a positive correlation between the width of the frequency response area of the neuron and the maximum level of SSA. The present data suggest that SSA in the IC is not mediated by the intrinsic membrane properties of the neurons and instead might be related to an excitatory and/or inhibitory input segregation.

  14. The effect of external magnetic field on the density distributions and electromagnetic fields in the interaction of high-intensity short laser pulse with collisionless underdense plasma

    NASA Astrophysics Data System (ADS)

    Mahmoodi-Darian, Masoomeh; Ettehadi-Abari, Mehdi; Sedaghat, Mahsa

    2016-03-01

    Laser absorption in the interaction between ultra-intense femtosecond laser and solid density plasma is studied theoretically here in the intensity range I{λ^2} ˜eq 10^{14}{-}10^{16}{{W}}{{{cm}}^{-2}} \\upmu{{{m}}2} . The collisionless effect is found to be significant when the incident laser intensity is less than 10^{16}{{W}}{{{cm}}^{-2}}\\upmu{{{m}}2} . In the current work, the propagation of a high-frequency electromagnetic wave, for underdense collisionless plasma in the presence of an external magnetic field is investigated. When a constant magnetic field parallel to the laser pulse propagation direction is applied, the electrons rotate along the magnetic field lines and generate the electromagnetic part in the wake with a nonzero group velocity. Here, by considering the ponderomotive force in attendance of the external magnetic field and assuming the isothermal collisionless plasma, the nonlinear permittivity of the plasma medium is obtained and the equation of electromagnetic wave propagation in plasma is solved. Here, by considering the effect of the ponderomotive force in isothermal collisionless magnetized plasma, it is shown that by increasing the laser pulse intensity, the electrons density profile leads to steepening and the electron bunches of plasma become narrower. Moreover, it is found that the wavelength of electric and magnetic field oscillations increases by increasing the external magnetic field and the density distribution of electrons also grows in comparison to the unmagnetized collisionless plasma.

  15. Waveguide CO{sub 2} laser with a quasi-homogeneous distribution of the output radiation intensity

    SciTech Connect

    Vlasenko, S A; Gurin, O V; Degtyarev, A V; Maslov, Vyacheslav A; Svich, V A; Topkov, A N

    2013-05-31

    An experimental sample of a waveguide CO{sub 2} laser with a quasi-uniform profile of the output radiation intensity is designed on the basis of a waveguide quasi-optical cavity of a new type comprising the generic confocal cavity with a nonuniform mirror and the hollow waveguide with the dimensions satisfying the conditions for self-imaging the quasi-uniform field. The surface of the mirror has the discrete large-scale absorbing nonuniformities. Results of theoretical and experimental investigations of spatial-energy characteristics of the laser in using uniform or amplitude-stepped reflecting mirrors are presented. (lasers)

  16. Continuum Level Density in Complex Scaling Method

    SciTech Connect

    Suzuki, R.; Myo, T.; Kato, K.

    2005-11-21

    A new calculational method of continuum level density (CLD) at unbound energies is studied in the complex scaling method (CSM). It is shown that the CLD can be calculated by employing the discretization of continuum states in the CSM without any smoothing technique.

  17. Turbulent fluid motion 3: Basic continuum equations

    NASA Technical Reports Server (NTRS)

    Deissler, Robert G.

    1991-01-01

    A derivation of the continuum equations used for the analysis of turbulence is given. These equations include the continuity equation, the Navier-Stokes equations, and the heat transfer or energy equation. An experimental justification for using a continuum approach for the study of turbulence is given.

  18. A continuum model for interconnected lattice trusses

    NASA Technical Reports Server (NTRS)

    Balakrishnan, A. V.

    1992-01-01

    A continuum model for interconnected lattice trusses based on the 1D Timoshenko beam approximation is developed using the NASA-LRC Phase Zero Evolutionary Model. The continuum model dynamics is presented in the canonical wave-equation form in a Hilbert space.

  19. Novel Continuum Modeling of Crystal Surface Evolution

    NASA Astrophysics Data System (ADS)

    Kandel, Daniel

    2003-03-01

    Below the roughening temperature the evolution of crystal surfaces proceeds by the nucleation, flow and annihilation of discrete atomic steps. The appropriate mathematical model of the evolution of such surfaces is discrete in nature, and consists of coupled equations for the motion, nucelation and annihilation of steps. It is useful, however, to describe surface evolution in terms of continuum models. Such models are more amenable to analytical treatments and have enormous computational advantages over their discrete counterparts. Standard continuum models successfully describe the evolution of surfaces with smooth morphology, but completely fail when the surface has singularities such as facets. It is an interesting and important challenge to develop continuum descriptions of surfaces with singularities, since in many cases the singularities drive the evolution of the whole system. In the talk I will present a conceptually new approach to continuum modeling of surface evolution, termed Configurational Continuum [1], which is valid even in singular regions. The approach consists of a new definition of the continuum limit. It is equivalent to standard continuum for very smooth morphology, but is radically different from it in singular regions, where it becomes equivalent to the discrete models. The validity of configurational continuum will be demonstrated on several simple systems. [1] N. Israeli and D. Kandel, Phys. Rev. Lett. 88, 116103 (2002).

  20. Electron-ion continuum-continuum mixing in dissociative recombination

    NASA Technical Reports Server (NTRS)

    Guberman, Steven L.

    1993-01-01

    In recent calculations on the dissociative recombination (DR) of the v=1 vibrational level of the ground state of N2(+), N2(+)(v=1) + e(-) yields N + N, we have observed an important continuun-continuum mixing process involving the open channels on both sides of N2(+)(v=1) + e(-) yields N2(+)(v=0) + e(-). In vibrational relaxation by electron impact (immediately above) the magnitude of the cross section depends upon the strength of the interaction between these continua. In DR of the v=1 ion level, these continua can also interact in the entrance channel, and the mixing can have a profound effect upon the DR cross section from v=1, as we illustrate in this paper. In our theoretical calculations of N2(+) DR using multichannel quantum defect theory (MQDT), the reactants and products in the two above equations are described simultaneously. This allows us to calculate vibrational relaxation and excitation cross sections as well as DR cross sections. In order to understand the mixing described above, we first present a brief review of the prior results for DR of the v=0 level of N2(+).

  1. Spatial distribution of diuron sorption affinity as affected by soil, terrain and management practices in an intensively managed apple orchard.

    PubMed

    Umali, Beng P; Oliver, Danielle P; Ostendorf, Bertram; Forrester, Sean; Chittleborough, David J; Hutson, John L; Kookana, Rai S

    2012-05-30

    We investigated how the sorption affinity of diuron (3'-(3,4-dichlorophenyl)-1,1-dimenthyl-urea), a moderately hydrophobic herbicide, is affected by soil properties, topography and management practices in an intensively managed orchard system. Soil-landscape analysis was carried out in an apple orchard which had a strong texture contrast soil and a landform with relief difference of 50 m. Diuron sorption (K(d)) affinity was successfully predicted (R(2)=0.79; p<0.001) using a mid-infrared - partial least squares model and calibrated against measured data using a conventional batch sorption technique. Soil and terrain properties explained 75% of the variance of diuron K(d) with TOC, pH(w), slope and WI as key variables. Mean diuron K(d) values were also significantly different (p<0.05) between alley and tree line and between the different management zones. Soil in the tree line generally had lower sorption capacity for diuron than soil in the alleys. Younger stands, which were found to have lower TOC than in the older stands, also had lower diuron K(d) values. In intensively managed orchards, sorption affinity of pesticides to soils was not only affected by soil properties and terrain attributes but also by management regime. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Tracing the Mass during Low-Mass Star Formation. I. Submillimeter Continuum Observations

    NASA Astrophysics Data System (ADS)

    Shirley, Yancy L.; Evans, Neal J., II; Rawlings, Jonathan M. C.; Gregersen, Erik M.

    2000-11-01

    We have obtained 850 and 450 μm continuum maps of 21 low-mass cores with SEDs ranging from pre-protostellar to Class I (18 Kintensity profiles, and photometry. Pre-protostellar cores do not have power-law intensity profiles, whereas the intensity profiles of Class 0 and Class I sources can be fitted with power laws over a large range of radii. A substantial number of sources have companion sources within a few arcminutes (two out of five pre-protostellar cores, nine out of 16 Class 0/I sources). The mean separation between sources is 10,800 AU. The median separation is 18,000 AU including sources without companions as a lower limit. The mean value of the spectral index between 450 and 850 μm is 2.8+/-0.4, with pre-protostellar cores having slightly lower spectral indices (2.5+/-0.4). The mean mass of the sample, based on the dust emission in a 120" aperture, is 1.1+/-0.9 Msolar. For the sources fitted by power-law intensity distributions (Iν(b)/Iν(0)=(b/b0)m), the mean value of m is 1.52+/-0.45 for Class 0 and I sources at 850 μm and 1.44+/-0.25 at 450 μm. Based on a simple analysis, assuming the emission is in the Rayleigh-Jeans limit and that Td(r)~r-0.4, these values of m translate into power-law density distributions (n~r-p) with p~2.1. However, we show that this result may be changed by more careful consideration of effects such as beam size and shape, finite outer radii, more realistic Td(r), and failure of the Rayleigh-Jeans approximation.

  3. Intense electrostatic waves near the upper hybrid resonance frequency. [beyond plasmapause

    NASA Technical Reports Server (NTRS)

    Kurth, W. S.; Craven, J. D.; Frank, L. A.; Gurnett, D. A.

    1979-01-01

    Plasma wave measurements using instruments on the Imp 6 and Hawkeye satellites are utilized in a study of very intense electrostatic waves near the upper hybrid resonance frequency in the region just outside the plasmapause. Studies of these electrostatic disturbances show that the events occur at local times and at magnetic latitudes varying from the equator to 50 deg, and the polarization of these waves is such that the wave electric field vector is oriented perpendicular to the geomagnetic field. In most cases the center frequency of the intense waves corresponds to an (n + 1/2) fg(-) harmonic near the upper hybrid resonance frequency. The hot distribution on function is described for a few events showing temperature anisotropy and a loss cone distribution. A possible mechanism for producing intense waves near the upper hybrid resonance frequency is suggested, and evidence which indicates that the intense electrostatic waves may be a source of nonthermal continuum radiation is given.

  4. Distribution and respiration of the high-latitude pelagic amphipod Themisto gaudichaudi in the Benguela Current in relation to upwelling intensity

    NASA Astrophysics Data System (ADS)

    Auel, Holger; Ekau, Werner

    2009-12-01

    The cold and highly productive waters of coastal upwelling areas provide habitats for marine species usually occurring at higher latitudes and allow those species to extend their distribution ranges towards the equator into regions otherwise characterised by warm and oligotrophic sub-tropical waters. The pelagic hyperiid amphipod Themisto gaudichaudi has a circum-Antarctic epipelagic distribution pattern generally south of 35°S and plays an important role in Antarctic food webs as effective link from zooplankton secondary production to higher trophic levels including seabirds and marine mammals. In the cold and productive waters of the Benguela Current coastal upwelling system, the distribution range of the species extents far northward into the subtropics. The present study focuses on the distribution of T. gaudichaudi at the northernmost limit of its range in the Benguela upwelling system in relation to upwelling intensity and hydrographic conditions (sea surface temperature) based on time-series data from 2002 to 2008. Moreover, field data on life-history traits and respiration rates in relation to water temperature are combined to elucidate the environmental and physiological factors limiting the distribution range. Compared to Themisto populations from higher latitudes, the relatively higher water temperatures in the coastal upwelling region lead to higher respiration rates, faster growth, earlier sexual maturity and smaller body size.

  5. High-order continuum kinetic method for modeling plasma dynamics in phase space

    DOE PAGES

    Vogman, G. V.; Colella, P.; Shumlak, U.

    2014-12-15

    Continuum methods offer a high-fidelity means of simulating plasma kinetics. While computationally intensive, these methods are advantageous because they can be cast in conservation-law form, are not susceptible to noise, and can be implemented using high-order numerical methods. Advances in continuum method capabilities for modeling kinetic phenomena in plasmas require the development of validation tools in higher dimensional phase space and an ability to handle non-cartesian geometries. To that end, a new benchmark for validating Vlasov-Poisson simulations in 3D (x,vx,vy) is presented. The benchmark is based on the Dory-Guest-Harris instability and is successfully used to validate a continuum finite volumemore » algorithm. To address challenges associated with non-cartesian geometries, unique features of cylindrical phase space coordinates are described. Preliminary results of continuum kinetic simulations in 4D (r,z,vr,vz) phase space are presented.« less

  6. The correlation between far-IR and radio continuum emission from spiral galaxies

    NASA Technical Reports Server (NTRS)

    Dickey, John M.; Garwood, Robert W.; Helou, George

    1987-01-01

    A sample of 30 galaxies selected for their intense IRAS flux at 60 and 100 micron using the Arecibo telescope at 21 cm to measure the continuum and HI line luminosities were observed. The centimeter wave continuum correlates very well with the far-infrared flux, with a correlation coefficient as high as that found for other samples, and the same ratio between FIR and radio luminosities. Weaker correlations are seen between the FIR and optical luminosity and between the FIR and radio continuum. There is very little correlation between the FIR and the HI mass deduced from the integral of the 21 cm line. The strength of the radio continuum correlation suggests that there is little contribution to either the radio and FIR from physical processes not affecting both. If they each reflect time integrals of the star formation rate then the time constants must be similar, or the star formation rate must change slowly in these galaxies.

  7. EDR: An Energy-Aware Runtime Load Distribution System for Data-Intensive Applications in the Cloud

    SciTech Connect

    Li, Bo; Song, Shuaiwen; Bezakova, Ivona; Cameron, Kirk

    2013-09-23

    Data centers account for a growing percentage of US power consumption. Energy e_ciency is now a first-class design constraint for the data centers that support cloud services. Service providers must distribute their data e_ciently across multiple data centers. This includes creation of data replicas that provide multiple copies of data for e_cient access. However, selecting replicas to maximize performance while minimizing energy waste is an open problem. State of the art replica selection approaches either do not address energy, lack scalability and/or are vulnerable to crashes due to use of a centralized coordinator. Therefore, we propose, develop and evaluate a simple cost-oriented decentralized replica selection system named EDR, implemented with two distributed optimization algorithms

  8. Spatial distribution on high-order-harmonic generation of an H2+ molecule in intense laser fields

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Ge, Xin-Lei; Wang, Tian; Xu, Tong-Tong; Guo, Jing; Liu, Xue-Shen

    2015-07-01

    High-order-harmonic generation (HHG) for the H2 + molecule in a 3-fs, 800-nm few-cycle Gaussian laser pulse combined with a static field is investigated by solving the one-dimensional electronic and one-dimensional nuclear time-dependent Schrödinger equation within the non-Born-Oppenheimer approximation. The spatial distribution in HHG is demonstrated and the results present the recombination process of the electron with the two nuclei, respectively. The spatial distribution of the HHG spectra shows that there is little possibility of the recombination of the electron with the nuclei around the origin z =0 a.u. and equilibrium internuclear positions z =±1.3 a.u. This characteristic is irrelevant to laser parameters and is only attributed to the molecular structure. Furthermore, we investigate the time-dependent electron-nuclear wave packet and ionization probability to further explain the underlying physical mechanism.

  9. Continuum lowering - A new perspective

    NASA Astrophysics Data System (ADS)

    Crowley, B. J. B.

    2014-12-01

    What is meant by continuum lowering and ionization potential depression (IPD) in a Coulomb system depends very much upon precisely what question is being asked. It is shown that equilibrium (equation of state) phenomena and non-equilibrium dynamical processes like photoionization are characterized by different values of the IPD. In the former, the ionization potential of an atom embedded in matter is the difference in the free energy of the many-body system between states of thermodynamic equilibrium differing by the ionization state of just one atom. Typically, this energy is less than that required to ionize the same atom in vacuo. Probably, the best known example of this is the IPD given by Stewart and Pyatt (SP). However, it is a common misconception that this formula should apply directly to the energy of a photon causing photoionization, since this is a local adiabatic process that occurs in the absence of a response from the surrounding plasma. To achieve the prescribed final equilibrium state, in general, additional energy, in the form of heat and work, is transferred between the atom and its surroundings. This additional relaxation energy is sufficient to explain the discrepancy between recent spectroscopic measurements of IPD in dense plasmas and the predictions of the SP formula. This paper provides a detailed account of an analytical approach, based on SP, to calculating thermodynamic and spectroscopic (adiabatic) IPDs in multicomponent Coulomb systems of arbitrary coupling strength with Te ≠ Ti. The ramifications for equilibrium Coulomb systems are examined in order to elucidate the roles of the various forms of the IPD and any possible connection with the plasma microfield. The formulation embodies an analytical equation of state (EoS) that is thermodynamically self-consistent, provided that the bound and free electrons are dynamically separable, meaning that the system is not undergoing pressure ionization. Apart from this restriction, the model is

  10. Effect of the Solar UV/EUV Heating on the Intensity and Spatial Distribution of Jupiter's Synchrotron Radiation

    NASA Astrophysics Data System (ADS)

    Kita, Hajime; Misawa, H.; Tsuchiya, F.; Tao, C.; Morioka, A.

    2012-10-01

    Jupiter's synchrotron radiation (JSR) is the emission from relativistic electrons, and it is the most effective probe for remote sensing of Jupiter's radiation belt from the Earth. Recent observations reveal short term variations of JSR with the time scale of days to weeks. Brice and McDonough (1973) proposed that the solar UV/EUV heating for Jupiter's upper atmosphere causes enhancement of total flux density. If such a process occurs at Jupiter, it is also expected that diurnal wind system produces dawn-dusk asymmetry of the JSR brightness distribution. Preceding studies confirmed that the short term variations in total flux density correspond to the solar UV/EUV. However, the effect of solar UV/EUV heating on the brightness distribution has not been confirmed. Hence, the purpose of this study is to confirm the solar UV/EUV heating effect on total flux density and brightness distribution. We made radio imaging analysis using the National Radio Astronomy Observatory (NRAO) archived data of the Very Large Array (VLA) obtained in 2000, and following results were shown. 1, Total flux density varied corresponding to the solar UV/EUV. 2, Dawn side emission was brighter than dusk side emission almost every day. 3, Variations of the dawn-dusk asymmetry did not correspond to the solar UV/EUV. In order to explain the second result, we estimate the diurnal wind velocity from the observed dawn-dusk ratio by using the model brightness distribution of JSR. Estimated neutral wind velocity is 46+/-11 m/s, which reasonably corresponds to the numerical simulation of Jupiter's upper atmosphere. In order to explain the third result, we examined the effect of the global convection electric field driven by tailward outflow of plasma in Jupiter's magnetosphere. As the result, it is suggested that typical fluctuation of the convection electric field strength was enough to cause the observed variations of the dawn-dusk asymmetry.

  11. Snow water equivalent spatiotemporal variability estimation in the Andes Cordillera through distributed energy balance modeling and intensive-study catchments.

    NASA Astrophysics Data System (ADS)

    McPhee, J. P.; Cornwell, E.; Molotch, N. P.

    2015-12-01

    Seasonal snow cover is the primary water resource precursor for human use and environmental sustain along the extratropical Andes Cordillera. This research provides high-resolution distributed estimates of end-of-winter and spring snow water equivalent over a 152,000-km2 domain, based on remotely sensed snow cover and a simplified snowpack energy balance model. Important data for model validation was obtained through a sustained effort aimed at monitoring snow conditions throughout the domain from newly installed sensors and snow surveys. Peak SWE estimates show an overall coefficient of determination R2 of 0.61 compared to observations at 12 automatic snow water equivalent sensors distributed across the model domain between latitudes 30º S and 37º S, with R2 values between 0.32 and 0.88. Estimated patterns of snow accumulation reflect appropriately the dominant effect of elevation, and suggest that the current government operational snow observation network may be inadequate under future climate change scenarios. Several insights can be obtained by analyzing the shortcomings of the modeling results when compared with high-resolution time series of energy and mass balance, as well as with distributed SWE observations obtained at experimental catchments. The results presented here have the potential of informing applications such as seasonal forecast model assessment and improvement, regional climate model validation, as well as evaluation of observational networks and water resource infrastructure development.

  12. The Distribution of Cloud to Ground Lightning Strike Intensities and Associated Magnetic Inductance Fields Near the Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Burns, Lee; Decker, Ryan

    2005-01-01

    Lightning strike location and peak current are monitored operationally in the Kennedy Space Center (KSC) Cape Canaveral Air Force Station (CCAFS) area by the Cloud to Ground Lightning Surveillance System (CGLSS). The present study compiles ten years worth of CGLSS data into a database of near strikes. Using shuffle launch platform LP39A as a convenient central point, all strikes recorded within a 20-mile radius for the period of record O R ) from January 1, 1993 to December 31,2002 were included in the subset database. Histograms and cumulative probability curves are produced for both strike intensity (peak current, in kA) and the corresponding magnetic inductance fields (in A/m). Results for the full POR have application to launch operations lightning monitoring and post-strike test procedures.

  13. Lattice continuum and diffusional creep

    NASA Astrophysics Data System (ADS)

    Mesarovic, Sinisa Dj.

    2016-04-01

    Diffusional creep is characterized by growth/disappearance of lattice planes at the crystal boundaries that serve as sources/sinks of vacancies, and by diffusion of vacancies. The lattice continuum theory developed here represents a natural and intuitive framework for the analysis of diffusion in crystals and lattice growth/loss at the boundaries. The formulation includes the definition of the Lagrangian reference configuration for the newly created lattice, the transport theorem and the definition of the creep rate tensor for a polycrystal as a piecewise uniform, discontinuous field. The values associated with each crystalline grain are related to the normal diffusional flux at grain boundaries. The governing equations for Nabarro-Herring creep are derived with coupled diffusion and elasticity with compositional eigenstrain. Both, bulk diffusional dissipation and boundary dissipation accompanying vacancy nucleation and absorption, are considered, but the latter is found to be negligible. For periodic arrangements of grains, diffusion formally decouples from elasticity but at the cost of a complicated boundary condition. The equilibrium of deviatorically stressed polycrystals is impossible without inclusion of interface energies. The secondary creep rate estimates correspond to the standard Nabarro-Herring model, and the volumetric creep is small. The initial (primary) creep rate is estimated to be much larger than the secondary creep rate.

  14. Lattice continuum and diffusional creep

    PubMed Central

    2016-01-01

    Diffusional creep is characterized by growth/disappearance of lattice planes at the crystal boundaries that serve as sources/sinks of vacancies, and by diffusion of vacancies. The lattice continuum theory developed here represents a natural and intuitive framework for the analysis of diffusion in crystals and lattice growth/loss at the boundaries. The formulation includes the definition of the Lagrangian reference configuration for the newly created lattice, the transport theorem and the definition of the creep rate tensor for a polycrystal as a piecewise uniform, discontinuous field. The values associated with each crystalline grain are related to the normal diffusional flux at grain boundaries. The governing equations for Nabarro–Herring creep are derived with coupled diffusion and elasticity with compositional eigenstrain. Both, bulk diffusional dissipation and boundary dissipation accompanying vacancy nucleation and absorption, are considered, but the latter is found to be negligible. For periodic arrangements of grains, diffusion formally decouples from elasticity but at the cost of a complicated boundary condition. The equilibrium of deviatorically stressed polycrystals is impossible without inclusion of interface energies. The secondary creep rate estimates correspond to the standard Nabarro–Herring model, and the volumetric creep is small. The initial (primary) creep rate is estimated to be much larger than the secondary creep rate. PMID:27274696

  15. Lattice continuum and diffusional creep.

    PubMed

    Mesarovic, Sinisa Dj

    2016-04-01

    Diffusional creep is characterized by growth/disappearance of lattice planes at the crystal boundaries that serve as sources/sinks of vacancies, and by diffusion of vacancies. The lattice continuum theory developed here represents a natural and intuitive framework for the analysis of diffusion in crystals and lattice growth/loss at the boundaries. The formulation includes the definition of the Lagrangian reference configuration for the newly created lattice, the transport theorem and the definition of the creep rate tensor for a polycrystal as a piecewise uniform, discontinuous field. The values associated with each crystalline grain are related to the normal diffusional flux at grain boundaries. The governing equations for Nabarro-Herring creep are derived with coupled diffusion and elasticity with compositional eigenstrain. Both, bulk diffusional dissipation and boundary dissipation accompanying vacancy nucleation and absorption, are considered, but the latter is found to be negligible. For periodic arrangements of grains, diffusion formally decouples from elasticity but at the cost of a complicated boundary condition. The equilibrium of deviatorically stressed polycrystals is impossible without inclusion of interface energies. The secondary creep rate estimates correspond to the standard Nabarro-Herring model, and the volumetric creep is small. The initial (primary) creep rate is estimated to be much larger than the secondary creep rate.

  16. Additive manufacturing of patient-specific tubular continuum manipulators

    NASA Astrophysics Data System (ADS)

    Amanov, Ernar; Nguyen, Thien-Dang; Burgner-Kahrs, Jessica

    2015-03-01

    Tubular continuum robots, which are composed of multiple concentric, precurved, elastic tubes, provide more dexterity than traditional surgical instruments at the same diameter. The tubes can be precurved such that the resulting manipulator fulfills surgical task requirements. Up to now the only material used for the component tubes of those manipulators is NiTi, a super-elastic shape-memory alloy of nickel and titan. NiTi is a cost-intensive material and fabrication processes are complex, requiring (proprietary) technology, e.g. for shape setting. In this paper, we evaluate component tubes made of 3 different thermoplastic materials (PLA, PCL and nylon) using fused filament fabrication technology (3D printing). This enables quick and cost-effective production of custom, patient-specific continuum manipulators, produced on site on demand. Stress-strain and deformation characteristics are evaluated experimentally for 16 fabricated tubes of each thermoplastic with diameters and shapes equivalent to those of NiTi tubes. Tubes made of PCL and nylon exhibit properties comparable to those made of NiTi. We further demonstrate a tubular continuum manipulator composed of 3 nylon tubes in a transnasal, transsphenoidal skull base surgery scenario in vitro.

  17. Relativistic continuum quasiparticle random-phase approximation in spherical nuclei

    SciTech Connect

    Daoutidis, I.; Ring, P.

    2011-04-15

    We have calculated the strength distributions of the dipole response in spherical nuclei, ranging all over the periodic table. The calculations were performed within two microscopic models: the discretized quasiparticle random-phase approximation and the continuum quasiparticle random-phase approximation, which takes into account the coupling of the single-particle continuum in an exact way. Pairing correlations are treated with the BCS model. In the calculations, two density functionals were used, namely, the PC-F1 and the DD-PC1. Both are based on relativistic point-coupling Lagrangians. It is explicitly shown that this model is capable of reproducing the giant- as well as the pygmy-dipole resonance for open-shell nuclei in a high level of quantitative agreement with the available experimental observations.

  18. Dynamic brittle material response based on a continuum damage model

    SciTech Connect

    Chen, E.P.

    1994-12-31

    The response of brittle materials to dynamic loads was studied in this investigation based on a continuum damage model. Damage mechanism was selected to be interaction and growth of subscale cracks. Briefly, the cracks are activated by bulk tension and the density of activated cracks are described by a Weibull statistical distribution. The moduli of a cracked solid derived by Budiansky and O`Connell are then used to represent the global material degradation due to subscale cracking. This continuum damage model was originally developed to study rock fragmentation and was modified in the present study to improve on the post-limit structural response. The model was implemented into a transient dynamic explicit finite element code PRONTO 2D and then used for a numerical study involving the sudden stretching of a plate with a centrally located hole. Numerical results characterizing the dynamic responses of the material were presented. The effect of damage on dynamic material behavior was discussed.

  19. 1.4 GHz continuum sources in the Cancer cluster

    NASA Technical Reports Server (NTRS)

    Salpeter, E. E.; Dickey, J. M.

    1987-01-01

    Results of 1.4-GHz continuum observations are presented for 11 VLA fields, using the D-configuration, which contain the A group of the Cnc cluster (CC). Sixteen Zwicky spiral galaxies in the CC were detected, but no ellipticals, confirming the finding that spiral galaxies with close companions tend to have enhanced radio emission. Over 200 continuum sources beyond the CC are tabulated. The spectral index (relative to 610 MHz) is given for many of the sources, including some of the Zwicky galaxies. There is a suggestion for a nonuniform number surface-density distribution of the sources, not correlated with the CC. Possible predictions of such nonuniformities, from assumptions on 'super-superclusters', are discussed.

  20. Phase space distribution of an electron beam emerging from Compton/Thomson back-scattering by an intense laser pulse

    NASA Astrophysics Data System (ADS)

    Petrillo, V.; Chaikovska, I.; Ronsivalle, C.; Rossi, A. R.; Serafini, L.; Vaccarezza, C.

    2013-01-01

    We analyze the energy distribution of a relativistic electron beam after the Compton back-scattering by a counterpropagating laser field. The analysis is performed for parameters in the range of realistic X-γ sources, in the framework of the Quantum Electrodynamics, by means of the code CAIN. The results lead to the conclusion that, in the regime considered, the main effect is the initial formation of stripes, followed by the diffusion of the most energetic particles toward lower values in the longitudinal phase space, with a final increase of the electron energy bandwidth.

  1. Z-scan measurements using femtosecond continuum generation.

    PubMed

    De Boni, Leonardo; Andrade, Acácio; Misoguti, Lino; Mendonça, Cléber; Zilio, Sérgio

    2004-08-23

    We present a single beam Z-scan technique using an intense, broadband, white-light continuum (WLC) beam for the direct measurement of nonlinear absorption spectra. In order to demonstrate the validity of our technique, we compared the results of tetraaniline and Sudan 3 solutions obtained with WLC and conventional single wavelength light sources. Both approaches lead to the same nonlinear spectrum, indicating that the association of the Z-scan technique and the WLC source results in an useful method for the measurement of nonlinear spectra of both absorbing (saturable absorption or reverse saturable absorption) and transparent (two-photon absorption) samples.

  2. Diagnostic Reasoning across the Medical Education Continuum

    PubMed Central

    Smith, C. Scott; Hill, William; Francovich, Chris; Morris, Magdalena; Robbins, Bruce; Robins, Lynne; Turner, Andrew

    2014-01-01

    We aimed to study linguistic and non-linguistic elements of diagnostic reasoning across the continuum of medical education. We performed semi-structured interviews of premedical students, first year medical students, third year medical students, second year internal medicine residents, and experienced faculty (ten each) as they diagnosed three common causes of dyspnea. A second observer recorded emotional tone. All interviews were digitally recorded and blinded transcripts were created. Propositional analysis and concept mapping were performed. Grounded theory was used to identify salient categories and transcripts were scored with these categories. Transcripts were then unblinded. Systematic differences in propositional structure, number of concept connections, distribution of grounded theory categories, episodic and semantic memories, and emotional tone were identified. Summary concept maps were created and grounded theory concepts were explored for each learning level. We identified three major findings: (1) The “apprentice effect” in novices (high stress and low narrative competence); (2) logistic concept growth in intermediates; and (3) a cognitive state transition (between analytical and intuitive approaches) in experts. These findings warrant further study and comparison. PMID:27429275

  3. Rotations of molecular photoelectron angular distributions in above threshold ionization of H2+ by intense circularly polarized attosecond UV laser pulses

    NASA Astrophysics Data System (ADS)

    Yuan, Kai-Jun; Chelkowski, Szczepan; Bandrauk, André D.

    2014-10-01

    We present molecular photoelectron angular distributions (MPADs) in multi-photon ionization processes by circularly polarized attosecond UV laser pulses. Simulations are performed on the single electron aligned molecular ion H_2^+ by solving corresponding 3D time-dependent Schrödinger equations. Numerical results of molecular above threshold ionization (MATI) show that rotations of MPADs with respect to the molecular and polarization axes depend on pulse intensities and photoelectron kinetic energies. We attribute the rotation to Γ, the difference between parallel and perpendicular ionization probabilities. It is found that in a resonant ionization process, the rotation angle is also a function of the symmetry of intermediate electronic states. The coherent population transfer between the initial and the resonant electronic states is controlled by pulse intensities. Such dependence of rotations on the pulse intensity is absent in Rydberg resonant ionizations as well as in MATI at large energy photons ℏω > Ip, where ω is angular frequency of photons and Ip is the molecular ionization potential. We describe these processes by a multi-photon perturbation theory model. Effects of molecular alignment and pulse ellipticities on rotations are investigated, confirming the essence of the ionization parameter Γ in rotations of MPADs.

  4. The role of precipitation size distributions in km-scale NWP simulations of intense precipitation: Evaluation of cloud properties and surface precipitation

    SciTech Connect

    Van Weverberg K.; Vogelmann A.; van Lipzig, N. P. M.; Delobbec, L.

    2012-04-01

    We investigate the sensitivity of simulated cloud properties and surface precipitation to assumptions regarding the size distributions of the precipitating hydrometeors in a one-moment bulk microphysics scheme. Three sensitivity experiments were applied to two composites of 15 convective and 15 frontal stratiform intense precipitation events observed in a coastal midlatitude region (Belgium), which were evaluated against satellite-retrieved cloud properties and radar-rain-gauge derived surface precipitation. It is found that the cloud optical thickness distribution was well captured by all experiments, although a significant underestimation of cloudiness occurred in the convective composite. The cloud-top-pressure distribution was improved most by more realistic snow size distributions (including a temperature-dependent intercept parameter and non-spherical snow for the calculation of the slope parameter), due to increased snow depositional growth at high altitudes. Surface precipitation was far less sensitive to whether graupel or hail was chosen as the rimed ice species, as compared to previous idealized experiments. This smaller difference in sensitivity could be explained by the stronger updraught velocities and higher freezing levels in the idealized experiments compared to typical coastal midlatitude environmental conditions.

  5. Continuum methods in lattice perturbation theory

    SciTech Connect

    Becher, Thomas G

    2002-11-15

    We show how methods of continuum perturbation theory can be used to simplify perturbative lattice calculations. We use the technique of asymptotic expansions to expand lattice loop integrals around the continuum limit. After the expansion, all nontrivial dependence on momenta and masses is encoded in continuum loop integrals and the only genuine lattice integrals left are tadpole integrals. Using integration-by-parts relations all of these can be expressed in terms of a small number of master integrals. Four master integrals are needed for bosonic one loop integrals, sixteen in QCD with Wilson or staggered fermions.

  6. Evaluation of Uncertainty-Based Stopping Criteria for Monte Carlo Calculations of Intensity-Modulated Radiotherapy and Arc Therapy Patient Dose Distributions

    SciTech Connect

    Vanderstraeten, Barbara Olteanu, Ana Maria Luiza; Reynaert, Nick; Leal, Antonio; Neve, Wilfried de; Thierens, Hubert

    2007-10-01

    Purpose: To formulate uncertainty-based stopping criteria for Monte Carlo (MC) calculations of intensity-modulated radiotherapy and intensity-modulated arc therapy patient dose distributions and evaluate their influence on MC simulation times and dose characteristics. Methods and Materials: For each structure of interest, stopping criteria were formulated as follows: {sigma}{sub rel} {<=}{sigma}{sub rel,tol} or D{sigma}{sub rel} {<=}D{sub lim}{sigma}{sub rel,tol} within {>=}95% of the voxels, where {sigma}{sub rel} represents the relative statistical uncertainty on the estimated dose, D. The tolerated uncertainty ({sigma}{sub rel,tol}) was 2%. The dose limit (D{sub lim}) equaled the planning target volume (PTV) prescription dose or a dose value related to the organ at risk (OAR) planning constraints. An intensity-modulated radiotherapy-lung, intensity-modulated radiotherapy-ethmoid sinus, and intensity-modulated arc therapy-rectum patient case were studied. The PTV-stopping criteria-based calculations were compared with the PTV+OAR-stopping criteria-based calculations. Results: The MC dose distributions complied with the PTV-stopping criteria after 14% (lung), 21% (ethmoid), and 12% (rectum) of the simulation times of a 100 million histories reference calculation, and increased to 29%, 44%, and 51%, respectively, by the addition of the OAR-stopping criteria. Dose-volume histograms corresponding to the PTV-stopping criteria, PTV+OAR-stopping criteria, and reference dose calculations were indiscernible. The median local dose differences between the PTV-stopping criteria and the reference calculations amounted to 1.4% (lung), 2.1% (ethmoid), and 2.5% (rectum). Conclusions: For the patient cases studied, the MC calculations using PTV-stopping criteria only allowed accurate treatment plan evaluation. The proposed stopping criteria provided a flexible tool to assist MC patient dose calculations. The structures of interest and appropriate values of {sigma}{sub rel

  7. Segmentation of 3-D High-Frequency Ultrasound Images of Human Lymph Nodes Using Graph Cut With Energy Functional Adapted to Local Intensity Distribution.

    PubMed

    Kuo, Jen-Wei; Mamou, Jonathan; Wang, Yao; Saegusa-Beecroft, Emi; Machi, Junji; Feleppa, Ernest J

    2017-10-01

    Previous studies by our group have shown that 3-D high-frequency quantitative ultrasound (QUS) methods have the potential to differentiate metastatic lymph nodes (LNs) from cancer-free LNs dissected from human cancer patients. To successfully perform these methods inside the LN parenchyma (LNP), an automatic segmentation method is highly desired to exclude the surrounding thin layer of fat from QUS processing and accurately correct for ultrasound attenuation. In high-frequency ultrasound images of LNs, the intensity distribution of LNP and fat varies spatially because of acoustic attenuation and focusing effects. Thus, the intensity contrast between two object regions (e.g., LNP and fat) is also spatially varying. In our previous work, nested graph cut (GC) demonstrated its ability to simultaneously segment LNP, fat, and the outer phosphate-buffered saline bath even when some boundaries are lost because of acoustic attenuation and focusing effects. This paper describes a novel approach called GC with locally adaptive energy to further deal with spatially varying distributions of LNP and fat caused by inhomogeneous acoustic attenuation. The proposed method achieved Dice similarity coefficients of 0.937±0.035 when compared with expert manual segmentation on a representative data set consisting of 115 3-D LN images obtained from colorectal cancer patients.

  8. Evaluation of moist processes during intense precipitation in km-scale NWP models using remote sensing and in-situ data: Impact of microphysics size distribution assumptions

    SciTech Connect

    Van Weverberg, K.; van Lipzig, N. P. M.; Delobbe, L.

    2011-02-01

    This study investigates the sensitivity of moist processes and surface precipitation during three extreme precipitation events over Belgium to the representation of rain, snow and hail size distributions in a bulk one-moment microphysics parameterisation scheme. Sensitivities included the use of empirically derived relations to calculate the slope parameter and diagnose the intercept parameter of the exponential snow and rain size distributions and sensitivities to the treatment of hail/graupel. A detailed evaluation of the experiments against various high temporal resolution and spatially distributed observational data was performed to understand how moist processes responded to the implemented size distribution modifications. Net vapor consumption by microphysical processes was found to be unaffected by snow or rain size distribution modifications, while it was reduced replacing formulations for hail by those typical for graupel, mainly due to intense sublimation of graupel. Cloud optical thickness was overestimated in all experiments and all cases, likely due to overestimated snow amounts. The overestimation slightly deteriorated by modifying the rain and snow size distributions due to increased snow depositional growth, while it was reduced by including graupel. The latter was mainly due to enhanced cloud water collection by graupel and reduced snow depositional growth. Radar reflectivity and cloud optical thickness could only be realistically represented by inclusion of graupel during a stratiform case, while hail was found indispensable to simulate the vertical reflectivity profile and the surface precipitation structure. Precipitation amount was not much altered by any of the modifications made and the general overestimation was only decreased slightly during a supercell convective case.

  9. Effect of solar UV/EUV heating on the intensity and spatial distribution of Jupiter's synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Kita, H.; Misawa, H.; Tsuchiya, F.; Tao, C.; Morioka, A.

    2013-10-01

    We analyzed the Very Large Array archived data observed in 2000 to determine whether solar ultraviolet (UV)/extreme ultraviolet (EUV) heating of the Jovian thermosphere causes variations in the total flux density and dawn-dusk asymmetry (the characteristic differences between the peak emissions at dawn and dusk) of Jupiter's synchrotron radiation (JSR). The total flux density varied by 10% over 6 days of observations and accorded with theoretical expectations. The average dawn-dusk peak emission ratio indicated that the dawn side emissions were brighter than those on the dusk side and this was expected to have been caused by diurnal wind induced by the solar UV/EUV. The daily variations in the dawn-dusk ratio did not correspond to the solar UV/EUV, and this finding did not support the theoretical expectation that the dawn-dusk ratio and diurnal wind velocity varies in correspondence with the solar UV/EUV. We tried to determine whether the average dawn-dusk ratio could be explained by a reasonable diurnal wind velocity. We constructed an equatorial brightness distribution model of JSR using the revised Divine-Garrett particle distribution model and used it to derive a relation between the dawn-dusk ratio and diurnal wind velocity. The estimated diurnal wind velocity reasonably corresponded to a numerical simulation of the Jovian thermosphere. We also found that realistic changes in the diurnal wind velocity could not cause the daily variations in the dawn-dusk ratio. Hence, we propose that the solar UV/EUV related variations were below the detection limit and some other processes dominated the daily variations in the dawn-dusk ratio.

  10. Unexpected size distribution of Ba(H2O)n clusters: why is the intensity of the Ba(H2O)1 cluster anomalously low?

    PubMed

    Cabanillas-Vidosa, Iván; Rossa, Maximiliano; Pino, Gustavo A; Ferrero, Juan C

    2011-08-07

    An experimental and theoretical study on the reactivity of neutral Ba atoms with water clusters has been conducted to unravel the origin of the irregular intensity pattern observed in one-photon ionization mass spectra of a Ba(H(2)O)(n)/BaOH(H(2)O)(n-1) (n = 1-4) cluster distribution, which was generated in a laser vaporization-supersonic expansion source. The most remarkable irregular feature is the finding for n = 1 of a lower intensity for the Ba(+)(H(2)O)(n) peak with respect to that of BaOH(+)(H(2)O)(n-1), which is opposite to the trend for n = 2-4. Rationalization of the data required consideration of a distinct behavior of ground-state and electronically excited state Ba atoms in inelastic and reactive Ba + (H(2)O)(n) encounters that can occur in the cluster source. Within this picture, the generation of Ba(H(2)O)(n) (n > 1) association products results from stabilizing collisions with atoms of the carrier gas, which are favored by intramolecular vibrational redistribution that operates on the corresponding collision intermediates prior to stabilization; the latter is unlikely to occur for Ba + (H(2)O) encounters. Overall, this interpretation is consistent with additional in-source laser excitation and quenching experiments, which aimed to explore qualitatively the effect of perturbing the Ba atom electronic state population distribution on the observed intensity pattern, as well as with the energetics of various possible reactions for the Ba + H(2)O system that derive from high level ab initio calculations.

  11. Effects of rain intensity, slope gradient and particle size distribution on the relative contributions of splash and wash loads to rain-induced erosion

    NASA Astrophysics Data System (ADS)

    Mahmoodabadi, Majid; Sajjadi, Sara Arjmand

    2016-01-01

    Soil erosion during rainfall is a complex phenomenon resulting from detachment by raindrop impact and overland flow. The objective of this study is to investigate the transportation rate of splash load (SL) and that of wash load (WL) and their relative contributions to the rain-induced erosion rate affected by rain intensity, slope gradient and particle size distribution. A total of 60 simulation runs were carried out using a detachment tray under simulated rainfall with no inflow. The experiments were done on two soil samples (aggregate sizes finer than 2 and 4.75 mm) from an agricultural land use at different rain intensities (57 and 80 mm h- 1) and varying slope gradients (0.5%, 2.5%, 5%, 10%, and 20%). Under unsteady state conditions, WL showed relatively high dependency on slope gradient, whereas approaching steady state conditions, nearly similar values of WL occurred at different slopes. SL and WL increased with increasing rain intensity and slope gradient, implying the importance of rain-induced erosion on bare agriculture lands especially at steeper slopes. The ratio of WL/SL decreased when slope gradient increased; however, WL increased more significantly than SL as soil aggregates became finer. The result indicates that at all the slope gradients, WL was much larger than SL, indicating that wash load significantly contributes to the rain-induced erosion in the agricultural soil. Furthermore, with increasing slope gradient, the contribution of wash load to rain-induced erosion decreased, while it was greater in the soil containing finer aggregates. Also, with increasing rain intensity at lower slope gradients (< 10%), further increase in splashed materials than that in washed materials occurred, whereas the reverse order was found at steeper slopes (> 10%). The finding of this study revealed that the rain-induced erosion was transport-limited at the gentler slopes, whereas at the steeper slopes, it shifted to detachment-limited conditions.

  12. The role of intense cyclones for precipitation, sea ice and snow cover distribution in the Nordic Seas

    NASA Astrophysics Data System (ADS)

    Moster Knudsen, Erlend; Crewell, Susanne; Hodges, Kevin; Rinke, Annette

    2017-04-01

    The Arctic is warming twice as fast as the global average. This feature, referred to as the Arctic amplification, is a result of and results in substantial changes in the regional cryosphere, heat and moisture transport. Here we present a study that investigates the impact cyclones in the Nordic Seas has on the regional precipitation, sea ice and snow cover distribution. Compositing late fall (October through December; OND) months of high and low cyclone-associated precipitation compared to its climatology 1979-2016, we identify the role these cyclones have on the regional precipitation amount and phase, sea ice, snow cover and sea surface temperature. Data for these time periods are from the reanalysis ERA-Interim and regional climate model HIRHAM5, while a short-term case study also includes weather station and satellite data for comparison and a more detailed analysis of the physical interactions. The results of this study are contributing to the understanding of the anomalous temperature, moisture and sea ice trends of the Barents Sea region compared to the Arctic-wide trends. Outcomes are also of substantial interest to actors following the opening up of the region. In this talk, the latest results of this ongoing study will be presented.

  13. Efficient white-light continuum generation in transparent solid media using ˜250 fs, 1053 nm laser pulses

    NASA Astrophysics Data System (ADS)

    Imran, T.; Figueira, G.

    2010-04-01

    We report white-light continuum generation in solid-state media (fused silica and sapphire) using seed pulses centered at 1053 nm and at a repetition rate of 10 Hz. We have investigated the influence of different parameters, such as changing the focal position and the energy of the incident pulse within the medium to obtain optimal white-light continuum. Preliminary results indicate that for intense laser pulses, waist position inside the media and input energy are crucial for high efficiency white-light continuum generation over the wavelength range 400-1100 nm. It was also found that pulses centered at 1053 nm generate a flatter spectrum, with higher white-light continuum efficiency. Such a flat response over a broad bandwidth in the continuum has the potential to be efficiently compressed to shorter durations.

  14. Noise scaling in continuum percolating films

    NASA Astrophysics Data System (ADS)

    Garfunkel, G. A.; Weissman, M. B.

    1985-07-01

    Measurements of the scaling of 1/f noise magnitude versus resistance were made in metal films as the metal was removed by sandblasting. This procedure gives an approximate experimental realization of a Swiss-cheese continuum-percolation model, for which theory indicates some scaling properties very different from lattice percolation. The ratio of the resistance and noise exponents was in strong disagreement with lattice-percolation predictions and agreed approximately with simple continuum predictions.

  15. Geometric continuum regularization of quantum field theory

    SciTech Connect

    Halpern, M.B. . Dept. of Physics)

    1989-11-08

    An overview of the continuum regularization program is given. The program is traced from its roots in stochastic quantization, with emphasis on the examples of regularized gauge theory, the regularized general nonlinear sigma model and regularized quantum gravity. In its coordinate-invariant form, the regularization is seen as entirely geometric: only the supermetric on field deformations is regularized, and the prescription provides universal nonperturbative invariant continuum regularization across all quantum field theory. 54 refs.

  16. Inferring changes in water cycle dynamics of intensively managed landscapes via the theory of time-variant travel time distributions

    NASA Astrophysics Data System (ADS)

    Danesh-Yazdi, Mohammad; Foufoula-Georgiou, Efi; Karwan, Diana L.; Botter, Gianluca

    2016-10-01

    Climatic trends and anthropogenic changes in land cover and land use are impacting the hydrology and water quality of streams at the field, watershed, and regional scales in complex ways. In poorly drained agricultural landscapes, subsurface drainage systems have been successful in increasing crop productivity by removing excess soil moisture. However, their hydroecological consequences are still debated in view of the observed increased concentrations of nitrate, phosphorus, and pesticides in many streams, as well as altered runoff volumes and timing. In this study, we employ the recently developed theory of time-variant travel time distributions within the StorAge Selection function framework to quantify changes in water cycle dynamics resulting from the combined climate and land use changes. Our results from analysis of a subbasin in the Minnesota River Basin indicate a significant decrease in the mean travel time of water in the shallow subsurface layer during the growing season under current conditions compared to the pre-1970s conditions. We also find highly damped year-to-year fluctuations in the mean travel time, which we attribute to the "homogenization" of the hydrologic response due to artificial drainage. The dependence of the mean travel time on the spatial heterogeneity of some soil characteristics as well as on the basin scale is further explored via numerical experiments. Simulations indicate that the mean travel time is independent of scale for spatial scales larger than approximately 200 km2, suggesting that hydrologic data from larger basins may be used to infer the average of smaller-scale-driven changes in water cycle dynamics.

  17. Emission of the third continuum of argon excited by a pulsed volume discharge

    SciTech Connect

    Lissovski, A. A.; Treshchalov, A. B.

    2009-12-15

    This paper presents the results of the observation of the third continuum band at 190 nm in a pulsed volume discharge at an argon pressure of 0.17-2 bar. The spatial-time kinetics of ultraviolet-visible photorecombination continuum and the third continuum of argon were measured and analyzed for the high- and low-current excitation regimes. Time-resolved imaging experiments with an intensified charge coupled device camera have shown that the second continuum of argon at 127 nm, Ar* lines and photorecombination continuum had a uniform distribution across the positive column of the discharge. However, the third continuum and Ar{sup +}* lines were emitted exclusively from the negative glow zone. This indicates to the existence of runaway electrons, accelerated in the electric field of the cathode layer and retarded in the negative glow zone. These electrons can achieve the energy of the cathode fall potential (130-250 eV). The radiative decay of the Ar{sub 2}{sup 2+} ions, created from Ar{sup 2+} precursors, is modeled. A good agreement has been achieved between the calculated and measured kinetics of the third continuum at different pressures, which supports the assignment of this continuum to the emission of Ar{sub 2}{sup 2+} ions. In contrast to the third continuum, the origin of the afterglow emission bands at 190 and 260 nm are connected with carbon-containing contaminants, accumulated inside the discharge chamber. These bands were disappeared during the gas circulation through the getter purifier.

  18. Using New Theory and Experimental Methods to Understand the Relative Controls of Storage, Antecedent Conditions and Precipitation Intensity on Transit Time Distributions through a Sloping Soil Lysimeter

    NASA Astrophysics Data System (ADS)

    Kim, M.; Pangle, L. A.; Cardoso, C.; Lora, M.; Wang, Y.; Harman, C. J.; Troch, P. A. A.

    2014-12-01

    Transit time distributions (TTD) are an efficient way of characterizing transport through the complex flow dynamics of a hydrologic system, and can serve as a basis for spatially-integrated solute transport modeling. Recently there has been progress in the development of a theory of time-variable TTDs that captures the effect of temporal variability in the timing of fluxes as well as changes in flow pathways. Furthermore, a new formulation of this theory allows the essential transport properties of a system to be parameterized by a physically meaningful time-variable probability distribution, the Ω function. This distribution determines how the age distribution of water in storage is sampled by the outflow. The form of the Ω function varies if the flow pathways change, but is not determined by the timing of fluxes (unlike the TTD). In this study, we use this theory to characterize transport by transient flows through a homogeneously packed 1 m3 sloping soil lysimeter. The transit time distribution associated with each of four irrigation periods (repeated daily for 24 days) are compared to examine the significance of changes in the Ω function due to variations in total storage, antecedent conditions, and precipitation intensity. We observe both the time-variable TTD and the Ω function experimentally by applying the PERTH method (Harman and Kim, 2014, GRL, 41, 1567-1575). The method allows us to observe multiple overlapping time-variable TTD in controlled experiments using only two conservative tracers. We hypothesize that both the TTD and the Ω function will vary in time, even in this small scale, because water will take different flow pathways depending on the initial state of the lysimeter and irrigation intensity. However, based on primarily modeling, we conjecture that major variability in the Ω function will be limited to a period during and immediately after each irrigation. We anticipate the Ω function is almost time-invariant (or scales simply with

  19. Effects of using a continuum representation of discrete fracture networks

    SciTech Connect

    Hull, L.C.; Clemo, T.M.

    1987-01-01

    The substitution of matrix or continuum permeability for discrete fracture permeability in the simulation of complex fracture systems requires a radically different treatment of transport in the matrix. The spatial distribution of pressure is reasonably well described by inclusion of only the major fractures. Transport of tracer and heat, however, depends on a detailed knowledge of fluid velocities. Two factors are involved. First, the velocities are dependent on the active porosity of the system. Because fractures channel flow, the active porosity may be much smaller than the total porosity of the system. Secondly, the distribution of velocities is generally not normally distributed precluding the use of a Gaussian dispersion model. Characterization of the active porosity and velocity distribution are necessary to quantify tracer and heat movement.

  20. Spatial distribution and implications to sources of halogenated flame retardants in riverine sediments of Taizhou, an intense e-waste recycling area in eastern China.

    PubMed

    Zhou, Shanshan; Fu, Jie; He, Huan; Fu, Jianjie; Tang, Qiaozhi; Dong, Minfeng; Pan, Yongqiang; Li, An; Liu, Weiping; Zhang, Limin

    2017-10-01

    Concentrations and spatial distribution pattern of organohalogen flame retardants were investigated in the riverine surface sediments from Taizhou, an intensive e-waste recycling region in China. The analytes were syn- and anti- Dechlorane Plus (DP), Dechloranes 602, 603, and 604, a DP monoadduct, two dechlorinated DPs and 8 congeners of polybrominated diphenyl ethers (PBDEs). The concentrations of Σ8PBDEs, ΣDP, ΣDec600s, and ΣDP-degradates ranged from <100 to 172,000, 100 to 55,000, not detectable (nd) to 1600, and nd to 2800 pg/g dry weight, respectively. BDE-209 and DP, both have been manufactured in China, had similar spatial distribution patterns in the study area, featured by distinctly recognizable hotspots some of which are in proximity to known e-waste dumping or metal recycling facilities. Such patterns were largely shared by Dec602 and dechlorinated DP, although their concentration levels were much lower. These major flame retardants significantly correlate with each other, and cluster together in the loading plot of principle component analysis. In contrast, most non-deca PBDE congeners do not correlate with DPs. Dec604 stood out having distinctly different spatial distribution pattern, which could be linked to historical use of mirex. Organic matter content of the sediment was not the dominant factor in determining the spatial pattern of pollution by halogenated flame retardants in the rivers of this study. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Effects of intensive insulin therapy alone and in combination with pioglitazone on body weight, composition, distribution and liver fat content in patients with type 2 diabetes.

    PubMed

    Shah, P K; Mudaliar, S; Chang, A R; Aroda, V; Andre, M; Burke, P; Henry, R R

    2011-06-01

    To evaluate the effects of intensive insulin therapy alone and with added pioglitazone on body weight, fat distribution, lean body mass (LBM) and liver fat in type 2 diabetic patients. Twenty-five insulin-treated, obese patients with type 2 diabetes were randomized to addition of pioglitazone 45 mg (n = 12) or placebo (n = 13) and treated intensively for 12-16 weeks. Dual-energy X-ray absorptiometry/abdominal computed tomography scans were performed before/after treatment. LBM, visceral/subcutaneous adipose tissue (VAT/SAT) and liver/spleen (L/S) attenuation ratios were measured pre-/posttreatment (a ratio <1 represents fatty liver). Intensive insulin alone and insulin + pioglitazone significantly improved glycaemic control (7.8 ± 0.3 to 7.2 ± 0.3% and 7.6 ± 0.3 to 7.1 ± 0.4%, respectively). Body weight gain was greater with insulin + pioglitazone (4.9 ± 4.5 kg) versus insulin therapy alone (1.7 ± 0.7 kg). SAT increased significantly with pioglitazone + insulin therapy (393.9 ± 48.5 to 443.2 ± 56.7 cm(2) , p < 0.01) compared to a non-significant increase with insulin therapy alone (412.9 ± 42.5 to 420.8 ± 43.8 cm(2) ). VAT decreased non-significantly in both groups (240.3 ± 41.7 to 223.8 ± 38.1 cm(2) with insulin + pioglitazone and 266.6 ± 27.4 to 250.5 ± 22.2 cm(2) with insulin therapy). LBM increased significantly by 1.92 ± 0.74 kg with insulin + pioglitazone treatment. The L/S attenuation ratio in the placebo + insulin group decreased from 1.08 ± 0.1 to 1.04 ± 0.1 (p = ns) and increased from 1.00 ± 0.1 to 1.08 ± 0.05 (p = 0.06) in the pioglitazone + insulin group. Intensification of insulin therapy in type 2 diabetic patients causes modest weight gain and no change in body fat distribution, LBM or liver fat. In contrast, the addition of pioglitazone, at equivalent glycaemia, increases weight gain, fat mass and SAT; increases LBM and tends to decrease liver fat. These changes in fat distribution may contribute to the beneficial effects of

  2. Haro 11: Where is the Lyman Continuum Source?

    NASA Astrophysics Data System (ADS)

    Keenan, Ryan P.; Oey, M. S.; Jaskot, Anne E.; James, Bethan L.

    2017-10-01

    Identifying the mechanism by which high-energy Lyman continuum (LyC) photons escaped from early galaxies is one of the most pressing questions in cosmic evolution. Haro 11 is the best known local LyC-leaking galaxy, providing an important opportunity to test our understanding of LyC escape. The observed LyC emission in this galaxy presumably originates from one of the three bright, photoionizing knots known as A, B, and C. It is known that Knot C has strong Lyα emission, and Knot B hosts an unusually bright ultraluminous X-ray source, which may be a low-luminosity active galactic nucleus. To clarify the LyC source, we carry out ionization-parameter mapping (IPM) by obtaining narrow-band imaging from the Hubble Space Telescope WFC3 and ACS cameras to construct spatially resolved ratio maps of [O iii]/[O ii] emission from the galaxy. IPM traces the ionization structure of the interstellar medium and allows us to identify optically thin regions. To optimize the continuum subtraction, we introduce a new method for determining the best continuum scale factor derived from the mode of the continuum-subtracted, image flux distribution. We find no conclusive evidence of LyC escape from Knots B or C, but instead we identify a high-ionization region extending over at least 1 kpc from Knot A. This knot shows evidence of an extremely young age (≲1 Myr), perhaps containing very massive stars (>100 M ⊙). It is weak in Lyα, so if it is confirmed as the LyC source, our results imply that LyC emission may be independent of Lyα emission.

  3. Influence of an intensive agricultural drainage basin on the seasonal distribution of organic pollutants in seawater from a Mediterranean coastal lagoon (Mar Menor, SE Spain).

    PubMed

    Moreno-González, R; Campillo, J A; León, V M

    2013-12-15

    The seasonal distribution of polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organochlorine pesticides, organophosphorus pesticides, triazines and other organic pollutants in surface seawater from the Mar Menor lagoon (SE Spain) was characterized from spring 2009 to winter 2010 by stir bar sorptive extraction and thermal desorption followed by capillary gas chromatography coupled to mass spectrometry (SBSE-GC-MS). The most ubiquitous pollutants were chlorpyrifos, chlortal-dimethyl, terbuthylazine, naphthalene and propyzamide throughout the year. Insecticides and herbicides were predominant in summer and spring, and fungicides were more abundant in autumn and winter. Chlorpyrifos was predominant in autumn and spring; herbicides (propyzamide, terbuthylazine and terbuthylazine-desethyl) in autumn and fungicides (flutolanil, boscalid, cyprodinil) in autumn and winter. The highest concentrations for the majority of pollutants were detected in autumn as consequence of air and surface/ground water inputs, and above all of desorption from terrigenous materials deposited in sediments by two intense flash flood events (September 2009).

  4. Dynamics of short-pulse generation via spectral filtering from intensely excited gain-switched 1.55-μm distributed-feedback laser diodes.

    PubMed

    Chen, Shaoqiang; Yoshita, Masahiro; Sato, Aya; Ito, Takashi; Akiyama, Hidefumi; Yokoyama, Hiroyuki

    2013-05-06

    Picosecond-pulse-generation dynamics and pulse-width limiting factors via spectral filtering from intensely pulse-excited gain-switched 1.55-μm distributed-feedback laser diodes were studied. The spectral and temporal characteristics of the spectrally filtered pulses indicated that the short-wavelength component stems from the initial part of the gain-switched main pulse and has a nearly linear down-chirp of 5.2 ps/nm, whereas long-wavelength components include chirped pulse-lasing components and steady-state-lasing components. Rate-equation calculations with a model of linear change in refractive index with carrier density explained the major features of the experimental results. The analysis of the expected pulse widths with optimum spectral widths was also consistent with the experimental data.

  5. Channel-specific photoelectron angular distribution in laboratory and molecular frames for dissociative ionization of methanol in intense ultraviolet laser fields

    NASA Astrophysics Data System (ADS)

    Fukahori, Shinichi; Nakano, Motoyoshi; Yamanouchi, Kaoru; Itakura, Ryuji

    2017-03-01

    We investigate dissociative ionization of CH3OH in an intense laser field (398 nm, 76 fs, 8.9 × 1012 W/cm2) by photoelectron-photoion coincidence momentum imaging. It is revealed from the analysis of the channel-specific photoelectron angular distributions that CH3OH is decomposed into CH2OH+ + H after the four-photon ionization to the vibrationally highly excited states of the electronic ground state of CH3OH+ and into CH3+ + OH after the five-photon ionization to the second electronically excited state of CH3OH+, and that these two channels are also opened after CH3OH+, prepared by the four-photon ionization, is photoexcited further into the electronically excited states.

  6. Angle-resolved intensity and energy distributions of positive and negative hydrogen ions released from tungsten surface by molecular hydrogen ion impact

    NASA Astrophysics Data System (ADS)

    Kato, S.; Tanaka, N.; Sasao, M.; Kisaki, M.; Tsumori, K.; Nishiura, M.; Matsumoto, Y.; Kenmotsu, T.; Wada, M.; Yamaoka, H.

    2015-08-01

    Hydrogen ion reflection properties have been investigated following the injection of H+, H2+ and H3+ ions onto a polycrystalline W surface. Angle- and energy-resolved intensity distributions of both scattered H+ and H- ions are measured by a magnetic momentum analyzer. We have detected atomic hydrogen ions reflected from the surface, while molecular hydrogen ions are unobserved within our detection limit. The reflected hydrogen ion energy is approximately less than one-third of the incident beam energy for H3+ ion injection and less than a half of that for H2+ ion injection. Other reflection properties are very similar to those of monoatomic H+ ion injection. Experimental results are compared to the classical trajectory simulations using the ACAT code based on the binary collision approximation.

  7. Tailoring Ion Charge State Distribution in Tetramethyltin Clusters under Influence of Moderate Intensity Picosecond Laser Pulse: Role of Laser Wavelength and Rate of Energy Deposition

    NASA Astrophysics Data System (ADS)

    Sharma, Pramod; Das, Soumitra; Vatsa, Rajesh K.

    2017-07-01

    Systematic manipulation of ionic-outcome in laser-cluster interaction process has been realized for studies carried out on tetramethyltin (TMT) clusters under picosecond laser conditions, determined by choice of laser wavelength and intensity. As a function of laser intensity, TMT clusters exhibit gradual enhancement in overall ionization of its cluster constituents, up to a saturation level of ionization, which was distinct for different wavelengths (266, 355, and 532 nm). Simultaneously, systematic appearance of higher multiply charged atomic ions and shift in relative abundance of multiply charged atomic ions towards higher charge state was observed, using time-of-flight mass spectrometer. At saturation level, multiply charged atomic ions up to (C2+, Sn2+) at 266 nm, (C4+, Sn4+) at 355 nm, and (C4+, Sn6+) at 532 nm were detected. In addition, at 355 nm intra-cluster ion chemistry within the ionized cluster leads to generation of molecular hydrogen ion (H2 +) and triatomic molecular hydrogen ion (H3 +). Generation of multiply charged atomic ions is ascribed to efficient coupling of laser pulse with the cluster media, facilitated by inner-ionized electrons produced within the cluster, at the leading edge of laser pulse. Role of inner-ionized electrons is authenticated by measuring kinetic energy distribution of electrons liberated upon disintegration of excessively ionized cluster, under the influence of picosecond laser pulse.

  8. DNA damage intensity in fibroblasts in a 3-dimensional collagen matrix correlates with the Bragg curve energy distribution of a high LET particle

    PubMed Central

    Roig, Andres I.; Hight, Suzie K.; Minna, John D.; Shay, Jerry W.; Rusek, Adam; Story, Michael D.

    2012-01-01

    Purpose The DNA double-strand break (DSB) damage response induced by high energy charged particles on lung fibroblast cells embedded in a 3-dimensional (3-D) collagen tissue equivalents was investigated using antibodies to the DNA damage response proteins gamma-histone 2AX (γ-H2AX) and phosphorylated DNA-PKcs (p-DNA-PKcs). Materials and methods 3-D tissue equivalents were irradiated in positions across the linear distribution of the Bragg curve profiles of 307.7 MeV/nucleon, 556.9 MeV/nucleon, or 967.0 MeV/nucleon 56Fe ions at a dose of 0.30 Gy. Results Patterns of discrete DNA damage streaks across nuclei or saturated nuclear damage were observed, with saturated nuclear damage being more predominant as samples were positioned closer to the physical Bragg peak. Quantification of the DNA damage signal intensities at each distance for each of the examined energies revealed a biological Bragg curve profile with a pattern of DNA damage intensity similar to the physical Bragg curve for the particular energy. Deconvolution microscopy of nuclei with streaked or saturated nuclear damage pattern revealed more details of the damage, with evidence of double-strand breaks radially distributed from the main particle track as well as multiple discrete tracks within saturated damage nuclei. Conclusions These 3-D culture systems can be used as a biological substrate to better understand the interaction of heavy charged particles of different energies with tissue and could serve as a basis to model space-radiation-induced cancer initiation and progression. PMID:20201648

  9. The Hurricane-Flood-Landslide Continuum

    NASA Technical Reports Server (NTRS)

    Negri, Andrew J.; Burkardt, Nina; Golden, Joseph H.; Halverson, Jeffrey B.; Huffman, George J.; Larsen, Matthew C.; McGinley, John A.; Updike, Randall G.; Verdin, James P.; Wieczorek, Gerald F.

    2005-01-01

    In August 2004, representatives from NOAA, NASA, the USGS, and other government agencies convened in San Juan, Puerto Rim for a workshop to discuss a proposed research project called the Hurricane-Flood-Landslide Continuum (HFLC). The essence of the HFLC is to develop and integrate tools across disciplines to enable the issuance of regional guidance products for floods and landslides associated with major tropical rain systems, with sufficient lead time that local emergency managers can protect vulnerable populations and infrastructure. All three lead agencies are independently developing precipitation-flood-debris flow forecasting technologies, and all have a history of work on natural hazards both domestically and overseas. NOM has the capability to provide tracking and prediction of storm rainfall, trajectory and landfall and is developing flood probability and magnTtude capabilities. The USGS has the capability to evaluate the ambient stability of natural and man-made landforms, to assess landslide susceptibilities for those landforms, and to establish probabilities for initiation of landslides and debris flows. Additionally, the USGS has well-developed operational capacity for real-time monitoring and reporting of streamflow across distributed networks of automated gaging stations (http://water.usgs.gov/waterwatch/). NASA has the capability to provide sophisticated algorithms for satellite remote sensing of precipitation, land use, and in the future, soil moisture. The Workshop sought to initiate discussion among three agencies regarding their specific and highly complimentary capabilities. The fundamental goal of the Workshop was to establish a framework that will leverage the strengths of each agency. Once a prototype system is developed for example, in relatively data-rich Puerto Rim, it could be adapted for use in data-poor, low-infrastructure regions such as the Dominican Republic or Haiti. This paper provides an overview of the Workshop s goals

  10. Distribution

    Treesearch

    John R. Jones

    1985-01-01

    Quaking aspen is the most widely distributed native North American tree species (Little 1971, Sargent 1890). It grows in a great diversity of regions, environments, and communities (Harshberger 1911). Only one deciduous tree species in the world, the closely related Eurasian aspen (Populus tremula), has a wider range (Weigle and Frothingham 1911)....

  11. Distributions.

    ERIC Educational Resources Information Center

    Bowers, Wayne A.

    This monograph was written for the Conference of the New Instructional Materials in Physics, held at the University of Washington in summer, 1965. It is intended for students who have had an introductory college physics course. It seeks to provide an introduction to the idea of distributions in general, and to some aspects of the subject in…

  12. Predicted continuum spectra of type II supernovae - LTE results

    NASA Technical Reports Server (NTRS)

    Shaviv, G.; Wehrse, R.; Wagoner, R. V.

    1985-01-01

    The continuum spectral energy distribution of the flux emerging from type II supernovae is calculated from quasi-static radiative transfer through a power-law density gradient, assuming radiative equilibrium and LTE. It is found that the Balmer jump disappears at high effective temperatures and low densities, while the spectrum resembles that of a dilute blackbody but is flatter with a sharper cutoff at the short-wavelength end. A significant UV excess is found in all models calculated. The calculation should be considered exploratory because of significant effects which are anticipated to arise from departure from LTE.

  13. Estimation of the distribution of low-intensity ultrasound mechanical index as a parameter affecting the proliferation of spermatogonia stem cells in vitro.

    PubMed

    Moghaddam, Zeinab Hormozi; Mokhtari-Dizaji, Manijhe; Movahedin, Mansoureh; Ravari, Mohammad Ehsan

    2017-07-01

    Considering the use of physical and mechanical stimulation, such as low-intensity ultrasound for proliferation and differentiation of stem cells, it is essential to understand the physical and acoustical mechanisms of acoustic waves in vitro. Mechanical index is used for quantifying acoustic cavitation and the relationship between acoustic pressure and the frequency. In this study, modeling of the mechanical index was applied to provide treatment protocol and to understand the effective physical processes on reproducibility of stem cells. Due to low intensity of ultrasound, Rayleigh integral model has been used for acoustic pressure computation. The acoustic pressure and mechanical index equations are modeled and solved to estimate optimal mechanical index for 28, 40, 150kHz and 1MHz frequencies. This model are solved in different intensities and distances from transducer in cylindrical coordinates. Based on the results of the mechanical index, regions with threshold mechanical index of 0.7 were identified for extracting of radiation arrangement to cell medium. Acoustic pressure distribution along the axial and radial was extracted. In order to validate the results of the modeling, the acoustic pressure in the water and near field depth was measured by a piston hydrophone. Results of modeling and experiments show that the model is consistent well to experimental results with 0.91 and 0.90 correlation of coefficient (p<0.05) for 1MHz and 40kHz. Low-intensity ultrasound with 0.40 mechanical index is more effective on enhancing the proliferation rate of the spermatogonia stem cells during the seven days of culture. In contrast, higher mechanical index has a harmful effect on the spermatogonial stem cells. Thus, considering cavitation threshold of different materials is necessary to find effective mechanical index ranges on proliferation for the used frequencies. This acoustic propagation model and ultrasound mechanical index assessments can be used with acceptable

  14. Temporal changes in distribution, prevalence and intensity of northern fowl mite (Ornithonyssus sylviarum) parasitism in commercial caged laying hens, with a comprehensive economic analysis of parasite impact.

    PubMed

    Mullens, Bradley A; Owen, Jeb P; Kuney, Douglas R; Szijj, Coralie E; Klingler, Kimberly A

    2009-03-09

    Establishment and spread of Ornithonyssus sylviarum were documented through time on sentinel hens (50 per house of 28,000-30,000 hens) in the first egg production cycle of three large commercial flocks (12 houses) of white leghorn hens. Mites were controlled using acaricide, and the impacts of treatment on mite populations and economic performance were documented. Mite prevalence and intensity increased rapidly and in tandem for 4-8 weeks after infestation. Intensity declined due to immune system involvement, but prevalence remained high, and this would affect mite sampling plan use and development. Early treatment was more effective at controlling mites; 85% of light infestations were eliminated by a pesticide spray (Ravap), versus 24% of heavy infestations. Hens infested later developed lower peak mite intensities, and those mite populations declined more quickly than on hens infested earlier in life. Raw spatial association by distance indices (SADIE), incorporating both the intensity and distribution of mites within a house, were high from week-to-week within a hen house. Once adjusted spatially to reflect variable hen cohorts becoming infested asynchronously, this analysis showed the association index tended to rebound at intervals of 5-6 weeks after the hen immune system first suppressed them. Large, consistent mite differences in one flock (high vs. low infestation levels) showed the economic damage of mite parasitism (assessed by flock indexing) was very high in the initial stages of mite expansion. Unmitigated infestations overall reduced egg production (2.1-4.0%), individual egg weights (0.5-2.2%), and feed conversion efficiency (5.7%), causing a profit reduction of $0.07-0.10 per hen for a 10-week period. Asynchronous infestation patterns among pesticide-treated hens may have contributed to a lack of apparent flock-level economic effects later in the production cycle. Individual egg weights differed with mite loads periodically, but could be either

  15. A continuum approach to phoretic motions: Thermophoresis

    NASA Astrophysics Data System (ADS)

    Brenner, Howard; Bielenberg, James R.

    2005-09-01

    A purely continuum theory for the thermophoretic velocity of aerosol and hydrosol particles in the zero Knudsen number, near continuum limit, Kn=0+, valid for both gases and liquids, is proposed. This theoretical result is based upon a fundamentally modified version of the traditional equations governing continuum fluid motion, one which accounts for an intrinsic difference in a fluid's barycentric (mass-based) velocity and its kinematic velocity of volume, this difference arising during molecular transport processes in fluids within which a mass density gradient exists. Our continuum-scale approach contains no free parameters, nor does it rely upon any sub-continuum, molecular concepts, such as Maxwell's thermally-induced velocity-slip condition. The resulting expression for the thermophoretic velocity of a non-Brownian, spherical particle agrees both constitutively and phenomenologically with available correlations of such velocity data in gases, as well as with the more limited data for liquids. Furthermore, the effect of shape and orientation is discussed for the case of non-spherical particles, with specific results furnished for effectively non-conducting particles. Agreement of the theory with the data furnishes explicit experimental support of the non-traditional fluid-mechanical equations utilized herein.

  16. Energy and angular distributions of electrons emitted by direct double auger decay.

    PubMed

    Viefhaus, Jens; Cvejanović, Slobodan; Langer, Burkhard; Lischke, Toralf; Prümper, Georg; Rolles, Daniel; Golovin, Alexander V; Grum-Grzhimailo, Alexei N; Kabachnik, Nikolai M; Becker, Uwe

    2004-02-27

    We have observed the direct L(2,3)MMM double Auger transition after photoionization of the 2p shell of argon by angle-resolved electron-electron coincidence spectroscopy. The process is responsible for about 20% of the observed Auger electron intensity. In contrast to the normal Auger lines, the spectra in double Auger decay show a continuous intensity distribution. The energy and angular distributions of the emitted electrons allow one to obtain information on the electron correlations giving rise to the double Auger process as well as the symmetry of the associated two-electron continuum state.

  17. Benchmark continuum and kinetic simulations of argon microplasmas in the direct current and microwave regimes

    NASA Astrophysics Data System (ADS)

    Verma, Abhishek Kumar; Alamatsaz, Arghavan; Venkattraman, Ayyaswamy

    2017-10-01

    This study presents benchmark comparisons between continuum and kinetic simulations of argon microplasmas operating in the direct current and microwave regimes. Kinetic simulations using the particle-in-cell with Monte Carlo collisions (PIC-MCC) method and continuum simulations using the full-momentum equation for both ions and electrons are performed at various operating conditions in order to study the influence of product of pressure and gap size, pd (for a given gap size), influence of gap size (for a given value of pd) and operating frequency. It is shown that using the electron energy distribution function (EEDF) predicted by zero-dimensional Boltzmann solvers (such as BOLSIG+) in continuum simulations of direct current microplasmas leads to a significant under-prediction of plasma number densities with continuum simulations based on the Maxwellian EEDF performing better particularly for higher values of pd. The discrepancy between kinetic and continuum simulations is attributed to the presence of hot electrons created as a result of secondary emission and subsequent acceleration in the sheath. On the other hand, simulations performed for argon microwave microplasmas operating at 0.5 GHz, 0.8 GHz, 2 GHz and 4 GHz demonstrated that continuum simulations performed using the rate constants from BOLSIG+  showed excellent agreement with kinetic simulations for the plasma density profiles in spite of over-predicting the voltage/power required to achieve a given plasma density.

  18. Generalized Chapman-Enskog continuum breakdown parameters for chemically reacting flows

    NASA Astrophysics Data System (ADS)

    Swaminathan-Gopalan, Krishnan; Subramaniam, Sharanya; Stephani, Kelly A.

    2016-12-01

    The generalized Chapman-Enskog (GCE) method for rapid and slow thermochemical processes is employed to formulate a set of continuum breakdown parameters for chemically reacting flows. These GCE breakdown parameters are derived for one-temperature, two-temperature, and three-temperature models, through classification of the relevant thermochemical time scales relative to fast elastic collisional processes and slow flow processes associated with changes in macroscopic observables. Continuum breakdown mechanisms owing to multicomponent diffusion, thermal diffusion, normal and shear stresses, Fourier-type heat fluxes based on translational, rotational, and vibrational temperatures, bulk viscosity, and relaxation pressure are presented for chemically reacting flows. The GCE breakdown parameters, derived from rigorous kinetic theory, capture the proper physical mechanism leading to continuum breakdown. These breakdown parameters are used to analyze continuum breakdown in a Mach 24 reacting air flow over a sphere and continuum breakdown is observed in the shock and close to the sphere surface. The flow field near the sphere surface is found to be characterized by sharp species concentration gradients due to gas-phase and surface reactions. Chemical reactions thus lead indirectly to the distortion of the velocity distribution function (VDF), providing a pathway to continuum breakdown that is captured by the GCE specieswise diffusion breakdown parameter.

  19. Revisiting the continuum model of tendon pathology: what is its merit in clinical practice and research?

    PubMed

    Cook, J L; Rio, E; Purdam, C R; Docking, S I

    2016-10-01

    The pathogenesis of tendinopathy and the primary biological change in the tendon that precipitates pathology have generated several pathoaetiological models in the literature. The continuum model of tendon pathology, proposed in 2009, synthesised clinical and laboratory-based research to guide treatment choices for the clinical presentations of tendinopathy. While the continuum has been cited extensively in the literature, its clinical utility has yet to be fully elucidated. The continuum model proposed a model for staging tendinopathy based on the changes and distribution of disorganisation within the tendon. However, classifying tendinopathy based on structure in what is primarily a pain condition has been challenged. The interplay between structure, pain and function is not yet fully understood, which has partly contributed to the complex clinical picture of tendinopathy. Here we revisit and assess the merit of the continuum model in the context of new evidence. We (1) summarise new evidence in tendinopathy research in the context of the continuum, (2) discuss tendon pain and the relevance of a model based on structure and (3) describe relevant clinical elements (pain, function and structure) to begin to build a better understanding of the condition. Our goal is that the continuum model may help guide targeted treatments and improved patient outcomes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  20. Revisiting the continuum model of tendon pathology: what is its merit in clinical practice and research?

    PubMed Central

    Cook, J L; Rio, E; Purdam, C R; Docking, S I

    2016-01-01

    The pathogenesis of tendinopathy and the primary biological change in the tendon that precipitates pathology have generated several pathoaetiological models in the literature. The continuum model of tendon pathology, proposed in 2009, synthesised clinical and laboratory-based research to guide treatment choices for the clinical presentations of tendinopathy. While the continuum has been cited extensively in the literature, its clinical utility has yet to be fully elucidated. The continuum model proposed a model for staging tendinopathy based on the changes and distribution of disorganisation within the tendon. However, classifying tendinopathy based on structure in what is primarily a pain condition has been challenged. The interplay between structure, pain and function is not yet fully understood, which has partly contributed to the complex clinical picture of tendinopathy. Here we revisit and assess the merit of the continuum model in the context of new evidence. We (1) summarise new evidence in tendinopathy research in the context of the continuum, (2) discuss tendon pain and the relevance of a model based on structure and (3) describe relevant clinical elements (pain, function and structure) to begin to build a better understanding of the condition. Our goal is that the continuum model may help guide targeted treatments and improved patient outcomes. PMID:27127294

  1. Electron density distribution of FeTiO3 ilmenite under high pressure analyzed by MEM using single crystal diffraction intensities

    NASA Astrophysics Data System (ADS)

    Yamanaka, Takamitsu; Komatsu, Yutaka; Nomori, Hironori

    2007-07-01

    Many of ilmenites ABO3 compounds bearing transition elements have semiconductive, ferroelectric and antiferromagnetic properties. The high-pressure diffraction studies of FeTiO3 have been conducted up to 8.2 GPa using synchrotron radiation in KEK at Tsukuba with diamond anvil cell. The compression mechanism of FeTiO3 ilmenite has been investigated by the structure refinements converged to the reliable factors R = 0.05. The deformations of the FeO6 and TiO6 octahedra were reduced with increasing pressure. In order to elucidate the electric conductivity change with pressure, electron density distribution of ilmenite have been executed by maximum entropy method (MEM) using single-crystal diffraction intensity data. MEM based on F obs( hkl) of FeTiO3 clearly shows electron density in comparison with the difference Fourier synthesis based on F obs( hkl) - F calc( hkl). The radial distribution of the electron density indicates electron localization around the cation positions. The bonding electron density found in bond Fe-O and Ti-O is lowered with pressure. The isotropic temperature factors B iso become smaller with increasing pressure. Nevertheless the thermal vibration is considerably restrained by the compression, the electric conductivity is enhanced with pressure. Neither charge transfer nor electron hopping between Fe and Ti along the c axis in FeTiO3 is plausible under high pressure. But the electric conductivity due to electron super-exchange in Fe-Fe and Ti-Ti has been clarified by the MEM electron density distribution. The anisotropy in the electric conductivity has been clarified.

  2. Microstructural and continuum evolution modeling of sintering.

    SciTech Connect

    Braginsky, Michael V.; Olevsky, Eugene A.; Johnson, D. Lynn; Tikare, Veena; Garino, Terry J.; Arguello, Jose Guadalupe, Jr.

    2003-12-01

    deformation during. The continuum portion is based on a finite element formulation that allows 3D components to be modeled using SNL's nonlinear large-deformation finite element code, JAS3D. This tool provides a capability to model sintering of complex three-dimensional components. The model was verified by comparing to simulations results published in the literature. The model was validated using experimental results from various laboratory experiments performed by Garino. In addition, the mesoscale simulations were used to study anisotropic shrinkage in aligned, elongated powder compacts. Anisotropic shrinkage occurred in all compacts with aligned, elongated particles. However, the direction of higher shrinkage was in some cases along the direction of elongation and in other cases in the perpendicular direction depending on the details of the powder compact. In compacts of simple-packed, mono-sized, elongated particles, shrinkage was higher in the direction of elongation. In compacts of close-packed, mono-sized, elongated particles and of elongated particles with a size and shape distribution, the shrinkage was lower in the direction of elongation. We also explored the concept of a sintering stress tensor rather than the traditional sintering stress scalar concept for the case of anisotropic shrinkage. A thermodynamic treatment of this is presented. A method to calculate the sintering stress tensor is also presented. A user-friendly code that can simulate microstructural evolution during sintering in 2D and in 3D was developed. This code can run on most UNIX platforms and has a motif-based GUI. The microstructural evolution is shown as the code is running and many of the microstructural features, such as grain size, pore size, the average grain boundary length (in 2D) and area (in 3D), etc. are measured and recorded as a function of time. The overall density as the function of time is also recorded.

  3. Continuum Absorption Coefficient of Atoms and Ions

    NASA Technical Reports Server (NTRS)

    Armaly, B. F.

    1979-01-01

    The rate of heat transfer to the heat shield of a Jupiter probe has been estimated to be one order of magnitude higher than any previously experienced in an outer space exploration program. More than one-third of this heat load is due to an emission of continuum radiation from atoms and ions. The existing computer code for calculating the continuum contribution to the total load utilizes a modified version of Biberman's approximate method. The continuum radiation absorption cross sections of a C - H - O - N ablation system were examined in detail. The present computer code was evaluated and updated by being compared with available exact and approximate calculations and correlations of experimental data. A detailed calculation procedure, which can be applied to other atomic species, is presented. The approximate correlations can be made to agree with the available exact and experimental data.

  4. Stiffness Control of Surgical Continuum Manipulators.

    PubMed

    Mahvash, Mohsen; Dupont, Pierre E

    2011-04-01

    This paper introduces the first stiffness controller for continuum robots. The control law is based on an accurate approximation of a continuum robot's coupled kinematic and static force model. To implement a desired tip stiffness, the controller drives the actuators to positions corresponding to a deflected robot configuration that produces the required tip force for the measured tip position. This approach provides several important advantages. First, it enables the use of robot deflection sensing as a means to both sense and control tip forces. Second, it enables stiffness control to be implemented by modification of existing continuum robot position controllers. The proposed controller is demonstrated experimentally in the context of a concentric tube robot. Results show that the stiffness controller achieves the desired stiffness in steady state, provides good dynamic performance, and exhibits stability during contact transitions.

  5. Continuum modeling of two-phase flows

    SciTech Connect

    Bataille, J.; Kestin, J.

    1981-12-01

    Continuum modeling of two-phase flows can essentially be achieved in two ways. The first approach, the so-called continuum theory of mixtures, ignores the details of the flow occurring on the microscopic level, while the second one is the result of some averaging procedure. Although they both lead, as expected, to the same set of basic equations, they differ strongly in their spirit when closure equations have to be found. In the present report, we have attempted to give a brief critical review of both approaches, to compare them and to discuss some of the major difficulties which arise. It is shown that the application of the continuum theory of mixtures is, in most cases, questionable and that the only appropriate way of finding closure equations, besides correlating experimental results, consists in a useful investigation of the microscopic flow pattern associated with an adequate averaging technique.

  6. Defining and testing a granular continuum element

    SciTech Connect

    Rycroft, Chris H.; Kamrin, Ken; Bazant, Martin Z.

    2007-12-03

    Continuum mechanics relies on the fundamental notion of amesoscopic volume "element" in which properties averaged over discreteparticles obey deterministic relationships. Recent work on granularmaterials suggests a continuum law may be inapplicable, revealinginhomogeneities at the particle level, such as force chains and slow cagebreaking. Here, we analyze large-scale Discrete-Element Method (DEM)simulations of different granular flows and show that a "granularelement" can indeed be defined at the scale of dynamical correlations,roughly three to five particle diameters. Its rheology is rather subtle,combining liquid-like dependence on deformation rate and solid-likedependence on strain. Our results confirm some aspects of classicalplasticity theory (e.g., coaxiality of stress and deformation rate),while contradicting others (i.e., incipient yield), and can guide thedevelopment of more realistic continuum models.

  7. Stiffness Control of Surgical Continuum Manipulators

    PubMed Central

    Mahvash, Mohsen; Dupont, Pierre E.

    2013-01-01

    This paper introduces the first stiffness controller for continuum robots. The control law is based on an accurate approximation of a continuum robot’s coupled kinematic and static force model. To implement a desired tip stiffness, the controller drives the actuators to positions corresponding to a deflected robot configuration that produces the required tip force for the measured tip position. This approach provides several important advantages. First, it enables the use of robot deflection sensing as a means to both sense and control tip forces. Second, it enables stiffness control to be implemented by modification of existing continuum robot position controllers. The proposed controller is demonstrated experimentally in the context of a concentric tube robot. Results show that the stiffness controller achieves the desired stiffness in steady state, provides good dynamic performance, and exhibits stability during contact transitions. PMID:24273466

  8. Modeling angiogenesis: A discrete to continuum description

    NASA Astrophysics Data System (ADS)

    Pillay, Samara; Byrne, Helen M.; Maini, Philip K.

    2017-01-01

    Angiogenesis is the process by which new blood vessels develop from existing vasculature. During angiogenesis, endothelial tip cells migrate via diffusion and chemotaxis, loops form via tip-to-tip and tip-to-sprout anastomosis, new tip cells are produced via branching, and a vessel network forms as endothelial cells follow the paths of tip cells. The latter process is known as the snail trail. We use a mean-field approximation to systematically derive a continuum model from a two-dimensional lattice-based cellular automaton model of angiogenesis in the corneal assay, based on the snail-trail process. From the two-dimensional continuum model, we derive a one-dimensional model which represents angiogenesis in two dimensions. By comparing the discrete and one-dimensional continuum models, we determine how individual cell behavior manifests at the macroscale. In contrast to the phenomenological continuum models in the literature, we find that endothelial cell creation due to tip cell movement (vessel formation via the snail trail) manifests as a source term of tip cells on the macroscale. Further, we find that phenomenological continuum models, which assume that endothelial cell creation is proportional to the flux of tip cells in the direction of increasing chemoattractant concentration, qualitatively capture vessel formation in two dimensions, but must be modified to accurately represent vessel formation. Additionally, we find that anastomosis imposes restrictions on cell density, which, if violated, leads to ill-posedness in our continuum model. We also deduce that self-loops should be excluded when tip-to-sprout anastomosis is active in the discrete model to ensure propagation of the vascular front.

  9. A Continuum Damage Model for Viscoelastic Materials

    DTIC Science & Technology

    1987-11-01

    CLASSIFICATION AUTHORITY 3b. DECLASSIFICATION/OOWNGRAOING SCHEDULE 4. PERFORMING ORGANIZATION REPORT NUMBER(S) MM- 4762 -87-17 e«. NAME OF PERFORMING...ENGINEERING SCIENCES DIRECTORATE CONTACT N00014-82-K-0562 M M- 4762 -87-17, / NOVEMEBER 1987 A CONTINUUM DAMAGE MODEL FOR VISCOELASTIC MATERIALS by Y...Contract F33615-67-C-1412), In "Workshop on a Continuum Mechanics Approach to Damage and Life Prediction" NSF-Solid Mechanics Program, 119. ASTM STP

  10. Continuum modeling of catastrophic collisions

    NASA Technical Reports Server (NTRS)

    Ryan, Eileen V.; Aspaug, Erik; Melosh, H. J.

    1991-01-01

    A two dimensional hydrocode based on 2-D SALE was modified to include strength effects and fragmentation equations for fracture resulting from tensile stress in one dimension. Output from this code includes a complete fragmentation summary for each cell of the modeled object: fragment size (mass) distribution, vector velocities of particles, peak values of pressure and tensile stress, and peak strain rates associated with fragmentation. Contour plots showing pressure and temperature at given times within the object are also produced. By invoking axial symmetry, three dimensional events can be modeled such as zero impact parameter collisions between asteroids. The code was tested against the one dimensional model and the analytical solution for a linearly increasing tensile stress under constant strain rate.

  11. Effects of light intensity and duration on leaf hydraulic conductance and distribution of resistance in shoots of silver birch (Betula pendula).

    PubMed

    Sellin, Arne; Ounapuu, Eele; Kupper, Priit

    2008-11-01

    Variation in leaf hydraulic conductance (K(L)) and distribution of resistance in response to light intensity and duration were examined in shoots of silver birch (Betula pendula Roth). K(L) was determined on detached shoots using the evaporative flux method (transpiration was measured with a porometer and water potential drop with a pressure chamber). Although K(L) depended on light duration per se, its dynamics was largely determined by leaf temperature (T(L)). Both upper-crown leaves and branches developed in well-illuminated environment exhibited higher hydraulic efficiency compared with the lower crown, accounting for vertical trends of apparent soil-to-leaf hydraulic conductance in canopy of silver birch revealed in our previous studies. K(L) varied significantly with light intensity, the highest values for both shade and sun foliage were recorded at photosynthetic photon flux density of 330 micromol m(-2) s(-1). Light responses of K(L) were associated evidently with an irradiance-mediated effect on extravascular tissues involving regulation of cell membrane aquaporins. Effects of irradiance on K(L) resulted in changes of Psi(L), bringing about considerable alteration in partitioning of the resistance between leaves and branch (leafless shoot stem): the contribution of leaves to the shoot total resistance decreased from 94% at -1.0 MPa to 75% at -0.2 MPa. Treatment with HgCl2 decreased hydraulic conductance of both leaves and branches, implying that condition of bordered pit membranes or shoot living tissues may be involved in responses of xylem conductance to Hg2+.

  12. AGN Space Telescope and Optical Reverberation Mapping Project II. Ultraviolet and Optical Continuum Analysis

    NASA Astrophysics Data System (ADS)

    Fausnaugh, Michael; Agn Storm Team

    2015-01-01

    The AGN STORM collaboration recently completed an extensive reverberation mapping campaign, targeting NGC 5548 with observations spanning the hard X-rays to mid-infrared. This campaign represents a massive collaborative effort, with far UV continuum spectrophotometry obtained through an intensive HST COS program, and near-UV/optical broad band photometry obtained from Swift and over 25 ground-based telescopes (in BVR and griz). The campaign spanned the entire 2014 observing season with virtually daily cadence, which allows us to compare with unprecedented accuracy the detailed structure of the observed UV and optical continuum emission signals in this archetypal AGN. We find statistically significant time delays between lightcurves from different wavebands, and this result has implications for the temperature, ionization, and geometric configuration of the AGN's sub-parsec scale environment. We will present the UV/optical continuum lightcurves from this campaign, as well as an analysis of the wavelength-dependent structure of the time delays.

  13. Coupled Particulate and Continuum Model for Nanoparticle Targeted Delivery

    PubMed Central

    Tan, Jifu; Wang, Shunqiang; Yang, Jie; Liu, Yaling

    2013-01-01

    Prediction of nanoparticle (NP) distribution in a vasculature involves transport phenomena at various scales and is crucial for the evaluation of NP delivery efficiency. A combined particulate and continuum model is developed to model NP transport and delivery processes. In the particulate model ligand-receptor binding kinetics is coupled with Brownian dynamics to study NP binding on a microscale. An analytical formula is derived to link molecular level binding parameters to particulate level adhesion and detachment rates. The obtained NP adhesion rates are then coupled with a convection-diffusion-reaction model to study NP transport and delivery at macroscale. The binding results of the continuum model agree well with those from the particulate model. The effects of shear rate, particle size and vascular geometry on NP adhesion are investigated. Attachment rates predicted by the analytical formula also agree reasonably well with the experimental data reported in literature. The developed coupled model that links ligand-receptor binding dynamics to NP adhesion rate along with macroscale transport and delivery processes may serve as a faster evaluation and prediction tool to determine NP distribution in complex vascular networks. PMID:23729869

  14. On the Nature of Off-limb Flare Continuum Sources Detected by SDO/HMI

    NASA Astrophysics Data System (ADS)

    Heinzel, P.; Kleint, L.; Kašparová, J.; Krucker, S.

    2017-09-01

    The Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory has provided unique observations of off-limb flare emission. White-light continuum enhancements were detected in the “continuum” channel of the Fe 6173 Å line during the impulsive phase of the observed flares. In this paper we aim to determine which radiation mechanism is responsible for such enhancement being seen above the limb, at chromospheric heights around or below 1000 km. Using a simple analytical approach, we compare two candidate mechanisms, the hydrogen recombination continuum (Paschen) and the Thomson continuum due to scattering of disk radiation on flare electrons. Both mechanisms depend on the electron density, which is typically enhanced during the impulsive phase of a flare as the result of collisional ionization (both thermal and also non-thermal due to electron beams). We conclude that for electron densities higher than 1012 cm‑3, the Paschen recombination continuum significantly dominates the Thomson scattering continuum and there is some contribution from the hydrogen free–free emission. This is further supported by detailed radiation-hydrodynamical (RHD) simulations of the flare chromosphere heated by the electron beams. We use the RHD code FLARIX to compute the temporal evolution of the flare-heating in a semi-circular loop. The synthesized continuum structure above the limb resembles the off-limb flare structures detected by HMI, namely their height above the limb, as well as the radiation intensity. These results are consistent with recent findings related to hydrogen Balmer continuum enhancements, which were clearly detected in disk flares by the IRIS near-ultraviolet spectrometer.

  15. Continuum Background in Space-Borne Gamma-Ray Detectors

    NASA Technical Reports Server (NTRS)

    Evans, Larry G.; Trombka, Jacob I; Starr, Richard; Boyton, William V.; Bailey, S.

    1997-01-01

    The background measured with space-borne gamma-ray spectrometers (GRS) in the 100 keV-10 MeV energy region consists of both discrete lines and continuum. The discrete lines originate in the decay of radioactive species. The continuum originates from a number of different processes and can be an important factor in the detection, for example, of weak gamma-ray lines from a planetary surface. Measurements of the gamma-ray background have been made during the cruise portion of a number of planetary missions. The three missions described here are the Apollo 15 and 16 missions each of which carried a 7 cm x 7 cm NaI scintillation detector, the Mars Observer (MO) mission which used a 5.5 cm X 5.5 cm high-purity germanium (HPGe) detector, and the Near Earth Rendezvous Asteroid (NEAR) mission that has a 2.54 cm x 7.6 cm NaI detector. A comparison of the intensity and spectral shape of these background spectra can be useful to help understand how these backgrounds vary with spacecraft size, detector position, and detector size. The use of shields to reduce the background components on these three missions is a test of the effectiveness of different shield designs.

  16. Dyson-Schwinger equations : density, temperature and continuum strong QCD.

    SciTech Connect

    Roberts, C. D.; Schmidt, S. M.; Physics

    2000-01-01

    Continuum strong QCD is the application of models and continuum quantum field theory to the study of phenomena in hadronic physics, which includes; e.g., the spectrum of QCD bound states and their interactions; and the transition to, and properties of, a quark gluon plasma. We provide a contemporary perspective, couched primarily in terms of the Dyson-Schwinger equations but also making comparisons with other approaches and models. Our discourse provides a practitioners' guide to features of the Dyson-Schwinger equations [such as confinement and dynamical chiral symmetry breaking] and canvasses phenomenological applications to light meson and baryon properties in cold, sparse QCD. These provide the foundation for an extension to hot, dense QCD, which is probed via the introduction of the intensive thermodynamic variables: chemical potential and temperature. We describe order parameters whose evolution signals deconfinement and chiral symmetry restoration, and chronicle their use in demarcating the quark gluon plasma phase boundary and characterizing the plasma's properties. Hadron traits change in an equilibrated plasma. We exemplify this and discuss putative signals of the effects. Finally, since plasma formation is not an equilibrium process, we discuss recent developments in kinetic theory and its application to describing the evolution from a relativistic heavy ion collision to an equilibrated quark gluon plasma.

  17. Continuum Background in Space-Borne Gamma-Ray Detectors

    NASA Astrophysics Data System (ADS)

    Evans, Larry G.; Trombka, Jacob I.; Starr, Richard; Boyton, William V.; Bailey, S.

    The background measured with space-borne gamma-ray spectrometers (GRS) in the 100 keV-10 MeV energy region consists of both discrete lines and continuum. The discrete lines originate in the decay of radioactive species. The continuum originates from a number of different processes and can be an important factor in the detection, for example, of weak gamma-ray lines from a planetary surface. Measurements of the gamma-ray background have been made during the cruise portion of a number of planetary missions. The three missions described here are the Apollo 15 and 16 missions each of which carried a 7 cm x 7 cm NaI scintillation detector, the Mars Observer (MO) mission which used a 5.5 cm X 5.5 cm high-purity germanium (HPGe) detector, and the Near Earth Rendezvous Asteroid (NEAR) mission that has a 2.54 cm x 7.6 cm NaI detector. A comparison of the intensity and spectral shape of these background spectra can be useful to help understand how these backgrounds vary with spacecraft size, detector position, and detector size. The use of shields to reduce the background components on these three missions is a test of the effectiveness of different shield designs.

  18. Radio continuum from FU Orionis stars

    SciTech Connect

    Rodriguez, L.F.; Hartmann, L.W.; Chavira, E. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA Instituto Nacional de Astrofisica, Optica y Electronica, Puebla )

    1990-12-01

    Using the very large array a sensitive search is conducted for 3.6-cm continuum emission toward four FU Orionis objects: FU Ori, V1515 Cyg, V1057 Cyg, and Elias 1-12. V1057 Cyg and Elias 1-12 at the level of about 0.1 mJy is detected. The association of radio continuum emission with these FU Ori objects strengthens a possible relation between FU Ori stars and objects like L 1551 IRS 5 and Z CMa that are also sources of radio continuum emission and have been proposed as post-FU Ori objects. Whether the radio continuum emission is caused by free-free emission from ionized ejecta or if it is optically thin emission from a dusty disk is discussed. It was determined that, in the archives of the Tonantzintla Observatory, a plate taken in 1957 does not show Elias 1-12. This result significantly narrows the time range for the epoch of the outburst of this source to between 1957 and 1965. 38 refs.

  19. Some Continuum Aspects of Data Assimilation

    NASA Technical Reports Server (NTRS)

    Cohn, Stephen E.; Menard, Richard

    1999-01-01

    A long-sought goal in data assimilation is to build more fully the time dimension into the data assimilation process. Truly four-dimensional data assimilation requires evolving second-moment information, namely the estimation error covariance, along with the state estimate itself. The continuum evolution equations for the estimation error covariance constitute a system of partial differential equations in six space dimensions, forced by a model error covariance and by the observations themselves. The high dimensionality of this system poses a difficult computational problem. Numerous methods have been proposed for approximate, discrete solution of this system of equations. Four-dimensional variational schemes solve these equations indirectly, while schemes based on Kalman filtering solve the equations more directly, usually on a small subspace of the full six-dimensional space. In both cases, most proposed solution methods are not derived from the continuum covariance evolution equations themselves. Instead, most methods simply inherit the discretization used for evolving the state estimate, either in the form of a discrete tangent linear model or, in the case of ensemble schemes, in the form of a fully nonlinear discrete model. In this lecture we show that solutions of the continuum covariance evolution equations possess simple properties that are not readily satisfied upon discretization of the equations. we give numerical examples illustrating that "inherited" discretizations sometimes fail to produce meaningfully accurate solutions. Finally, we suggest alternative discretization methods that may yield more faithful approximate solutions of the continuum problem.

  20. Aims, Modes, and the Continuum of Discourse.

    ERIC Educational Resources Information Center

    Beale, Walter H.

    A framework for the study of discourse, based on the analysis of three superordinate features of discourse (asymmetry, hierarchy, and continuum), is proposed in this paper. The paper begins by noting the confusion in terminology that exists in the world of composition pedagogy and theory; pointing to the need for a framework for testing,…