Science.gov

Sample records for absorption maximum position

  1. Position and Confidence Limits of an Extremum: The Determination of the Absorption Maximum in Wide Bands.

    ERIC Educational Resources Information Center

    Heilbronner, Edgar

    1979-01-01

    Discusses the determination of the position of the absorption maximum in wide bands as well as the confidence limits for such calculations. A simple method, suited for pocket calculators, for the numerical evaluation of these calculations is presented. (BB)

  2. Maximum entropy and drug absorption.

    PubMed

    Charter, M K; Gull, S F

    1991-10-01

    The application of maximum entropy to the calculation of drug absorption rates was introduced in an earlier paper. Here it is developed further, and the whole procedure is presented as a problem in scientific inference to be solved using Bayes' theorem. Blood samples do not need to be taken at equally spaced intervals, and no smoothing, interpolation, extrapolation, or other preprocessing of the data is necessary. The resulting input rate estimates are smooth and physiologically realistic, even with noisy data, and their accuracy is quantified. Derived quantities such as the proportion of the dose absorbed, and the mean and median absorption times, are also obtained, together with their error estimates. There are no arbitrarily valued parameters in the analysis, and no specific functional form, such as an exponential or polynomial, is assumed for the input rate functions. PMID:1783989

  3. Maximum likelihood estimation of vehicle position for outdoor image sensor-based visible light positioning system

    NASA Astrophysics Data System (ADS)

    Zhao, Xiang; Lin, Jiming

    2016-04-01

    Image sensor-based visible light positioning can be applied not only to indoor environments but also to outdoor environments. To determine the performance bounds of the positioning accuracy from the view of statistical optimization for an outdoor image sensor-based visible light positioning system, we analyze and derive the maximum likelihood estimation and corresponding Cramér-Rao lower bounds of vehicle position, under the condition that the observation values of the light-emitting diode (LED) imaging points are affected by white Gaussian noise. For typical parameters of an LED traffic light and in-vehicle camera image sensor, simulation results show that accurate estimates are available, with positioning error generally less than 0.1 m at a communication distance of 30 m between the LED array transmitter and the camera receiver. With the communication distance being constant, the positioning accuracy depends on the number of LEDs used, the focal length of the lens, the pixel size, and the frame rate of the camera receiver.

  4. Maximum likelihood positioning and energy correction for scintillation detectors

    NASA Astrophysics Data System (ADS)

    Lerche, Christoph W.; Salomon, André; Goldschmidt, Benjamin; Lodomez, Sarah; Weissler, Björn; Solf, Torsten

    2016-02-01

    An algorithm for determining the crystal pixel and the gamma ray energy with scintillation detectors for PET is presented. The algorithm uses Likelihood Maximisation (ML) and therefore is inherently robust to missing data caused by defect or paralysed photo detector pixels. We tested the algorithm on a highly integrated MRI compatible small animal PET insert. The scintillation detector blocks of the PET gantry were built with the newly developed digital Silicon Photomultiplier (SiPM) technology from Philips Digital Photon Counting and LYSO pixel arrays with a pitch of 1 mm and length of 12 mm. Light sharing was used to readout the scintillation light from the 30× 30 scintillator pixel array with an 8× 8 SiPM array. For the performance evaluation of the proposed algorithm, we measured the scanner’s spatial resolution, energy resolution, singles and prompt count rate performance, and image noise. These values were compared to corresponding values obtained with Center of Gravity (CoG) based positioning methods for different scintillation light trigger thresholds and also for different energy windows. While all positioning algorithms showed similar spatial resolution, a clear advantage for the ML method was observed when comparing the PET scanner’s overall single and prompt detection efficiency, image noise, and energy resolution to the CoG based methods. Further, ML positioning reduces the dependence of image quality on scanner configuration parameters and was the only method that allowed achieving highest energy resolution, count rate performance and spatial resolution at the same time.

  5. Maximum likelihood positioning and energy correction for scintillation detectors.

    PubMed

    Lerche, Christoph W; Salomon, André; Goldschmidt, Benjamin; Lodomez, Sarah; Weissler, Björn; Solf, Torsten

    2016-02-21

    An algorithm for determining the crystal pixel and the gamma ray energy with scintillation detectors for PET is presented. The algorithm uses Likelihood Maximisation (ML) and therefore is inherently robust to missing data caused by defect or paralysed photo detector pixels. We tested the algorithm on a highly integrated MRI compatible small animal PET insert. The scintillation detector blocks of the PET gantry were built with the newly developed digital Silicon Photomultiplier (SiPM) technology from Philips Digital Photon Counting and LYSO pixel arrays with a pitch of 1 mm and length of 12 mm. Light sharing was used to readout the scintillation light from the [Formula: see text] scintillator pixel array with an [Formula: see text] SiPM array. For the performance evaluation of the proposed algorithm, we measured the scanner's spatial resolution, energy resolution, singles and prompt count rate performance, and image noise. These values were compared to corresponding values obtained with Center of Gravity (CoG) based positioning methods for different scintillation light trigger thresholds and also for different energy windows. While all positioning algorithms showed similar spatial resolution, a clear advantage for the ML method was observed when comparing the PET scanner's overall single and prompt detection efficiency, image noise, and energy resolution to the CoG based methods. Further, ML positioning reduces the dependence of image quality on scanner configuration parameters and was the only method that allowed achieving highest energy resolution, count rate performance and spatial resolution at the same time. PMID:26836394

  6. Harnessing the electromagnetic absorptions of metamaterials for positive applications

    NASA Astrophysics Data System (ADS)

    Xiang, Yuanjiang; Zou, Yanhong; Luo, Hailu; Dai, Xiaoyu; Wen, Shuangchun; Fan, Dianyuan

    2010-08-01

    Absorption or loss is inevitable for the metal-based metamaterials (MMs) due to the intrinsic loss of the metal, and constitutes a major hurdle to the practical realization of most applications such as a sub-wavelength lens. Thus, to reduce the losses becomes one of the major challenges in the MM field. However, the inevitable loss can also be harnessed to take a positive role in the applications of MMs such as stealth technology or other types of cloaking devices. In this presentation, after a brief review of the advances in MMs-based absorbers, we present several schemes to fulfill the desired electromagnetic absorption properties, both linear and nonlinear. For linear absorption, we have experimentally demonstrated that the absorption performance of an ordinary microwave absorbing material can be evidently improved by using the electric resonance resulting from an array of subwavelength metallic circuit elements. For nonlinear absorption, we show theoretically that the active linear magnetic permeability induces a nonlinear absorption, similar to the two-photon absorption (TPA), of electric field in a lossy MM with a Kerr-type nonlinear polarization.

  7. 14 CFR 27.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 27.1395 Section 27.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 27.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  8. 14 CFR 27.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 27.1395 Section 27.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 27.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  9. 14 CFR 25.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 25.1395 Section 25.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 25.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  10. 14 CFR 25.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 25.1395 Section 25.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 25.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  11. 14 CFR 25.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 25.1395 Section 25.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 25.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  12. 14 CFR 29.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 29.1395 Section 29.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 29.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  13. 14 CFR 23.1395 - Maximum intensities in overlapping beams of position lights.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Maximum intensities in overlapping beams of position lights. 23.1395 Section 23.1395 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT... AIRPLANES Equipment Lights § 23.1395 Maximum intensities in overlapping beams of position lights....

  14. 14 CFR 23.1395 - Maximum intensities in overlapping beams of position lights.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Maximum intensities in overlapping beams of position lights. 23.1395 Section 23.1395 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT... AIRPLANES Equipment Lights § 23.1395 Maximum intensities in overlapping beams of position lights....

  15. 14 CFR 27.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 27.1395 Section 27.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 27.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  16. 14 CFR 27.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 27.1395 Section 27.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 27.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  17. 14 CFR 23.1395 - Maximum intensities in overlapping beams of position lights.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maximum intensities in overlapping beams of position lights. 23.1395 Section 23.1395 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT... AIRPLANES Equipment Lights § 23.1395 Maximum intensities in overlapping beams of position lights....

  18. 14 CFR 23.1395 - Maximum intensities in overlapping beams of position lights.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maximum intensities in overlapping beams of position lights. 23.1395 Section 23.1395 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT... AIRPLANES Equipment Lights § 23.1395 Maximum intensities in overlapping beams of position lights....

  19. 14 CFR 29.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 29.1395 Section 29.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 29.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  20. 14 CFR 29.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 29.1395 Section 29.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 29.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  1. 14 CFR 29.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 29.1395 Section 29.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 29.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  2. 14 CFR 25.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 25.1395 Section 25.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 25.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  3. Sensitivity of depth of maximum and absorption depth of EAS to hadron production mechanism

    NASA Technical Reports Server (NTRS)

    Antonov, R. A.; Ivanenko, I. P.; Kanevsky, B. L.; Kuzmin, V. A.; Galkin, V. I.; Hein, L. A.

    1985-01-01

    Comparison of experimental data on depth of extensive air showers (EAS) development maximum in the atmosphere, T sub M and path of absorption, lambda, in the lower atmosphere of EAS with fixed particle number in the energy region eV with the results of calculation show that these parameters are sensitive mainly to the inelastic interaction cross section and scaling violation in the fragmentation and pionization region. The data are explained in a unified manner within the framework of a model in which scaling is violated slightly in the fragmentation region and strongly in the pionization region at primary cosmic rays composition close to the normal one and a permanent increase of inelastic interaction cross section. It is shown that, while interpreting the experimental data, disregard of two methodical points causes a systematic shift in T sub M: (1) shower selection system; and (2) EAS electron lateral distribution when performing the calculations on basis of which the transfer is made from the Cerenkov pulse FWHM to the depth of shower maximum, T sub M.

  4. Comparison of several protocols for the computational prediction of the maximum absorption wavelength of chrysanthemin.

    PubMed

    Soto-Rojo, Rody; Baldenebro-López, Jesús; Flores-Holguín, Norma; Glossman-Mitnik, Daniel

    2014-08-01

    UV-Vis spectra were calculated using time-dependent density functional theory for the chrysanthemin pigment, which is used as natural dye in dye sensitized solar cells. To this end, we studied four different calculation protocols in order to obtain the best approximation according to the maximum absorption wavelength (λmax) of the experimental spectrum. Furthermore, the optimized geometry, highest occupied molecular orbitals, lowest unoccupied molecular orbitals and electron density were calculated and analyzed. Several chemical models were used with and without the presence of the chlorine atom: the chosen functionals, B3LYP, PBE0 and the M06 family, represent various approximations with different fractions of Hartree-Fock exchange energy. These functionals were combined with the 6-31+G (d), 6-311+G (d) and the MIDIX+basis sets. All of these calculation protocols proved a good option, though the B3LYP/MIDIX+chemistry model was the best for predicting the λmax value, using the equilibrium calculation protocol (M1a) in the presence of chlorine. PMID:25060149

  5. Position Sensorless Control of IPMSMs Based on a Novel Flux Model Suitable for Maximum Torque Control

    NASA Astrophysics Data System (ADS)

    Matsumoto, Atsushi; Hasegawa, Masaru; Matsui, Keiju

    In this paper, a novel position sensorless control method for interior permanent magnet synchronous motors (IPMSMs) that is based on a novel flux model suitable for maximum torque control has been proposed. Maximum torque per ampere (MTPA) control is often utilized for driving IPMSMs with the maximum efficiency. In order to implement this control, generally, the parameters are required to be accurate. However, the inductance varies dramatically because of magnetic saturation, which has been one of the most important problems in recent years. Therefore, the conventional MTPA control method fails to achieve maximum efficiency for IPMSMs because of parameter mismatches. In this paper, first, a novel flux model has been proposed for realizing the position sensorless control of IPMSMs, which is insensitive to Lq. In addition, in this paper, it has been shown that the proposed flux model can approximately estimate the maximum torque control (MTC) frame, which as a new coordinate aligned with the current vector for MTPA control. Next, in this paper, a precise estimation method for the MTC frame has been proposed. By this method, highly accurate maximum torque control can be achieved. A decoupling control algorithm based on the proposed model has also been addressed in this paper. Finally, some experimental results demonstrate the feasibility and effectiveness of the proposed method.

  6. A maximum likelihood approach to estimating articulator positions from speech acoustics

    SciTech Connect

    Hogden, J.

    1996-09-23

    This proposal presents an algorithm called maximum likelihood continuity mapping (MALCOM) which recovers the positions of the tongue, jaw, lips, and other speech articulators from measurements of the sound-pressure waveform of speech. MALCOM differs from other techniques for recovering articulator positions from speech in three critical respects: it does not require training on measured or modeled articulator positions, it does not rely on any particular model of sound propagation through the vocal tract, and it recovers a mapping from acoustics to articulator positions that is linearly, not topographically, related to the actual mapping from acoustics to articulation. The approach categorizes short-time windows of speech into a finite number of sound types, and assumes the probability of using any articulator position to produce a given sound type can be described by a parameterized probability density function. MALCOM then uses maximum likelihood estimation techniques to: (1) find the most likely smooth articulator path given a speech sample and a set of distribution functions (one distribution function for each sound type), and (2) change the parameters of the distribution functions to better account for the data. Using this technique improves the accuracy of articulator position estimates compared to continuity mapping -- the only other technique that learns the relationship between acoustics and articulation solely from acoustics. The technique has potential application to computer speech recognition, speech synthesis and coding, teaching the hearing impaired to speak, improving foreign language instruction, and teaching dyslexics to read. 34 refs., 7 figs.

  7. The epoch state navigation filter. [for maximum likelihood estimates of position and velocity vectors

    NASA Technical Reports Server (NTRS)

    Battin, R. H.; Croopnick, S. R.; Edwards, J. A.

    1977-01-01

    The formulation of a recursive maximum likelihood navigation system employing reference position and velocity vectors as state variables is presented. Convenient forms of the required variational equations of motion are developed together with an explicit form of the associated state transition matrix needed to refer measurement data from the measurement time to the epoch time. Computational advantages accrue from this design in that the usual forward extrapolation of the covariance matrix of estimation errors can be avoided without incurring unacceptable system errors. Simulation data for earth orbiting satellites are provided to substantiate this assertion.

  8. Design of Cellular Composite Sandwich Panels for Maximum Blast Resistance Via Energy Absorption

    NASA Astrophysics Data System (ADS)

    McConnell, Jennifer Righman; Su, Hong

    2015-10-01

    This paper presents a design methodology for optimizing the energy absorption under blast loads of cellular composite sandwich panels. A combination of dynamic finite element analysis (FEA) and simplified analytical modeling techniques are used. The analytical modeling calculates both the loading effects and structural response resulting from user-input charge sizes and standoff distances and offers the advantage of expediting iterative design processes. The FEA and the analytical model results are compared and contrasted then used to compare the energy response of various cellular composite sandwich panels under blast loads, where various core shapes and dimensions are the focus. As a result, it is concluded that the optimum shape consists of vertically-oriented webs while the optimum dimensions can be generally described as those which cause the most inelasticity without failure of the webs. These dimensions are also specifically quantified for select situations. This guidance is employed, along with the analytical method developed by the authors and considerations of the influences of material properties, to suggest a general design procedure that is a simple yet sufficiently accurate method for design. The suggested design approach is also demonstrated through a design example.

  9. Design of Cellular Composite Sandwich Panels for Maximum Blast Resistance Via Energy Absorption

    NASA Astrophysics Data System (ADS)

    McConnell, Jennifer Righman; Su, Hong

    2016-06-01

    This paper presents a design methodology for optimizing the energy absorption under blast loads of cellular composite sandwich panels. A combination of dynamic finite element analysis (FEA) and simplified analytical modeling techniques are used. The analytical modeling calculates both the loading effects and structural response resulting from user-input charge sizes and standoff distances and offers the advantage of expediting iterative design processes. The FEA and the analytical model results are compared and contrasted then used to compare the energy response of various cellular composite sandwich panels under blast loads, where various core shapes and dimensions are the focus. As a result, it is concluded that the optimum shape consists of vertically-oriented webs while the optimum dimensions can be generally described as those which cause the most inelasticity without failure of the webs. These dimensions are also specifically quantified for select situations. This guidance is employed, along with the analytical method developed by the authors and considerations of the influences of material properties, to suggest a general design procedure that is a simple yet sufficiently accurate method for design. The suggested design approach is also demonstrated through a design example.

  10. Position Sensorless Vector Control for Permanent Magnet Synchronous Motors Based on Maximum Torque Control Frame

    NASA Astrophysics Data System (ADS)

    Hida, Hajime; Tomigashi, Yoshio; Kishimoto, Keiji

    High efficiency drive can be achieved by the maximum torque-per-ampere (MTPA) control which used reluctance torque effectively. However, the calculations for estimating rotor position and for controlling the d-axis current are required. The motor parameters of inductance etc. that are easily affected by magnetic saturation are included in those calculations. This paper proposes a new MTPA control method, which is robust against changes of motor parameters caused by magnetic saturation. In addition, complex calculation for d-axis current or reference to the table is not necessary. In this method, we define a novel coordinate frame, which has one axis aligned with the current vector of the MTPA control, and estimate the frame directly. Because the parameter Lqm for estimating the frame is less affected by the magnetic saturation than the conventional Lq, the effect of magnetic saturation on the position estimation can be greatly suppressed. First, an extended electromotive force model based on the proposed frame and a parameter Lqm for an estimation of the frame are derived. Next, the effectiveness of this proposed method is confirmed by simulations and experiments.

  11. The effect of particle vertical positioning on the absorption enhancement in plasmonic organic solar cells

    NASA Astrophysics Data System (ADS)

    Wang, Shu-Yi; Borca-Tasciuc, Diana-Andra; Kaminski, Deborah A.

    2012-06-01

    The light absorption enhancement of an organic solar cell with plasmonic nanoparticles (NP) embedded in the active layer is studied employing 3D finite element simulation. The effect of the vertical positioning of the particle monolayer inside the active layer is elucidated. The results indicate that the highest enhancement is obtained when the particles lay at the bottom of the active layer, an organization less difficult to control accurately in practice. The paper also discusses the difference in the absorption enhancement obtained for two existing definitions currently used in the literature. The results show that models assessing absorption by taking both host and nanoparticles into consideration may overpredict the enhancement even when integration is carried out only over the wavelength interval where the host absorption dominates.

  12. 14 CFR 25.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... position light intensity may exceed the applicable values in the following table, except as provided in... white in dihedral angle L 5 1 Rear white in dihedral angle R 5 1 Where— (a) Area A includes all directions in the adjacent dihedral angle that pass through the light source and intersect the...

  13. 14 CFR 29.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... position light intensity may exceed the applicable values in the following table, except as provided in... white in dihedral angle L 5 1 Rear white in dihedral angle R 5 1 Where— (a) Area A includes all directions in the adjacent dihedral angle that pass through the light source and intersect the...

  14. 14 CFR 27.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... position light intensity may exceed the applicable values in the following table, except as provided in... white in dihedral angle L 5 1 Rear white in dihedral angle R 5 1 Where— (a) Area A includes all directions in the adjacent dihedral angle that pass through the light source and intersect the...

  15. 14 CFR 23.1395 - Maximum intensities in overlapping beams of position lights.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... position light intensity may exceed the applicable values in the following equal or exceed the applicable... white in dihedral angle L 5 1 Rear white in dihedral angle R 5 1 Where— (a) Area A includes all directions in the adjacent dihedral angle that pass through the light source and intersect the...

  16. Truck loading positions for maximum live load girder moment in skewed integral bridges

    NASA Astrophysics Data System (ADS)

    Yalcin, O. Fatih

    2015-12-01

    In this study, the effect of the longitudinal and transverse truck positions on the distribution of live load moment among the girders of skewed integral abutment bridges (SIBs) is investigated. For this purpose, three dimensional finite element models (FEMs) of several single-span SIBs are built and analyzed. In the analyses, bridges with various skew angles under all possible single and double truck loading positions both in longitudinal and transverse directions are considered. An automated analysis procedure managed by a visual basic program is developed to obtain the structural models and apply the wheel loads of trucks. The finite element analyses (FEA) results are then used to find the most critical loading cases of single truck and adjacent two trucks for the live load moment in the girders of SIBs. The results revealed that, the trucks should be placed nearby the midline of the bridge deck in a diagonal manner.

  17. Positive feedback produces broad distributions in maximum activation attained within a narrow time window in stochastic biochemical reactions

    NASA Astrophysics Data System (ADS)

    Das, Jayajit

    2013-01-01

    How do single cell fate decisions induced by activation of key signaling proteins above threshold concentrations within a time interval are affected by stochastic fluctuations in biochemical reactions? We address this question using minimal models of stochastic chemical reactions commonly found in cell signaling and gene regulatory systems. Employing exact solutions and semi-analytical methods we calculate distributions of the maximum value (N) of activated species concentrations (Pmax(N)) and the time (t) taken to reach the maximum value (Pmax(t)) within a time interval in the minimal models. We find, the presence of positive feedback interactions make Pmax(N) more spread out with a higher "peakedness" in Pmax(t). Thus positive feedback interactions may help single cells to respond sensitively to a stimulus when cell decision processes require upregulation of activated forms of key proteins to a threshold number within a time window.

  18. Moments of the Position of the Maximum for GUE Characteristic Polynomials and for Log-Correlated Gaussian Processes

    NASA Astrophysics Data System (ADS)

    Fyodorov, Yan V.; Doussal, Pierre Le

    2016-05-01

    We study three instances of log-correlated processes on the interval: the logarithm of the Gaussian unitary ensemble (GUE) characteristic polynomial, the Gaussian log-correlated potential in presence of edge charges, and the Fractional Brownian motion with Hurst index H → 0 (fBM0). In previous collaborations we obtained the probability distribution function (PDF) of the value of the global minimum (equivalently maximum) for the first two processes, using the freezing-duality conjecture (FDC). Here we study the PDF of the position of the maximum x_m through its moments. Using replica, this requires calculating moments of the density of eigenvalues in the β -Jacobi ensemble. Using Jack polynomials we obtain an exact and explicit expression for both positive and negative integer moments for arbitrary β >0 and positive integer n in terms of sums over partitions. For positive moments, this expression agrees with a very recent independent derivation by Mezzadri and Reynolds. We check our results against a contour integral formula derived recently by Borodin and Gorin (presented in the Appendix 1 from these authors). The duality necessary for the FDC to work is proved, and on our expressions, found to correspond to exchange of partitions with their dual. Performing the limit n → 0 and to negative Dyson index β → -2 , we obtain the moments of x_m and give explicit expressions for the lowest ones. Numerical checks for the GUE polynomials, performed independently by N. Simm, indicate encouraging agreement. Some results are also obtained for moments in Laguerre, Hermite-Gaussian, as well as circular and related ensembles. The correlations of the position and the value of the field at the minimum are also analyzed.

  19. Moments of the Position of the Maximum for GUE Characteristic Polynomials and for Log-Correlated Gaussian Processes

    NASA Astrophysics Data System (ADS)

    Fyodorov, Yan V.; Doussal, Pierre Le

    2016-07-01

    We study three instances of log-correlated processes on the interval: the logarithm of the Gaussian unitary ensemble (GUE) characteristic polynomial, the Gaussian log-correlated potential in presence of edge charges, and the Fractional Brownian motion with Hurst index H → 0 (fBM0). In previous collaborations we obtained the probability distribution function (PDF) of the value of the global minimum (equivalently maximum) for the first two processes, using the freezing-duality conjecture (FDC). Here we study the PDF of the position of the maximum x_m through its moments. Using replica, this requires calculating moments of the density of eigenvalues in the β -Jacobi ensemble. Using Jack polynomials we obtain an exact and explicit expression for both positive and negative integer moments for arbitrary β >0 and positive integer n in terms of sums over partitions. For positive moments, this expression agrees with a very recent independent derivation by Mezzadri and Reynolds. We check our results against a contour integral formula derived recently by Borodin and Gorin (presented in the Appendix 1 from these authors). The duality necessary for the FDC to work is proved, and on our expressions, found to correspond to exchange of partitions with their dual. Performing the limit n → 0 and to negative Dyson index β → -2, we obtain the moments of x_m and give explicit expressions for the lowest ones. Numerical checks for the GUE polynomials, performed independently by N. Simm, indicate encouraging agreement. Some results are also obtained for moments in Laguerre, Hermite-Gaussian, as well as circular and related ensembles. The correlations of the position and the value of the field at the minimum are also analyzed.

  20. Separating components of variation in measurement series using maximum likelihood estimation. Application to patient position data in radiotherapy

    NASA Astrophysics Data System (ADS)

    Sage, J. P.; Mayles, W. P. M.; Mayles, H. M.; Syndikus, I.

    2014-10-01

    Maximum likelihood estimation (MLE) is presented as a statistical tool to evaluate the contribution of measurement error to any measurement series where the same quantity is measured using different independent methods. The technique was tested against artificial data sets; generated for values of underlying variation in the quantity and measurement error between 0.5 mm and 3 mm. In each case the simulation parameters were determined within 0.1 mm. The technique was applied to analyzing external random positioning errors from positional audit data for 112 pelvic radiotherapy patients. Patient position offsets were measured using portal imaging analysis and external body surface measures. Using MLE to analyze all methods in parallel it was possible to ascertain the measurement error for each method and the underlying positional variation. In the (AP / Lat / SI) directions the standard deviations of the measured patient position errors from portal imaging were (3.3 mm / 2.3 mm / 1.9 mm), arising from underlying variations of (2.7 mm / 1.5 mm / 1.4 mm) and measurement uncertainties of (1.8 mm / 1.8 mm / 1.3 mm), respectively. The measurement errors agree well with published studies. MLE used in this manner could be applied to any study in which the same quantity is measured using independent methods.

  1. Positive feedback produces broad distributions in maximum activation attained within a narrow time window in stochastic biochemical reactions

    NASA Astrophysics Data System (ADS)

    Das, Jayajit

    2013-03-01

    Stochastic fluctuations in biochemical reactions can regulate single cell decision processes. Using exact solutions and semi-analytical methods we calculate distributions of the maximum value (N) of species concentrations (Pmax (N)) and the time (t) taken to reach the maximum value (Pmax (t)) in minimal models of stochastic chemical reactions commonly found in cell signaling systems. We find, the presence of positive feedback interactions make Pmax (N) more spread out with a higher ``peakedness'' in Pmax (t) . Thus positive feedback interactions may help single cells to respond sensitively to a stimulus when cell decision processes require upregulation of activated forms of key proteins to a threshold number within a time window. Moreover, unlike other models of strongly correlated random variables such as Brownian walks or fluctuating interfaces, the extreme value distributions for the chemical reactions display multiscaling behavior emphasizing the presence of many time scales in cell signaling kinetics. This work was funded by the Research Institute at the Nationwide Children's Hospital and a grant (1R56AI090115-01A1) from the NIH.

  2. Sonic-boom measurements in the focus region during the ascent of Apollo 17. [maximum positive overpressure, positive impulse, signature duration, and bow-shock rise time

    NASA Technical Reports Server (NTRS)

    Henderson, H. R.; Hilton, D. A.

    1974-01-01

    Sonic-boom pressure signatures recorded during the ascent phase of Apollo 17 are presented. The measurements were obtained onboard six U.S. Navy ships positioned along the ground track of the spacecraft vehicle in the area of expected focus resulting from the flight path and acceleration of the vehicle. Tracings of the measured signatures are presented along with values of the maximum positive overpressure, positive impulse, signature duration, and bowshock rise time. Also included are brief descriptions of the ships and their location, the deployment of the sonic-boom instrumentation, flight profiles and operating conditions for the launch vehicle and spacecraft, surface-weather and sea-state information at the measuring sites, and high-altitude weather information for the general measurement areas. Comparisons of the measured and predicted sonic-boom overpressures for the Apollo 17 mission are presented. The measured data are also compared with data from the Apollo 15 and 16 missions and data from flight test programs of various aircraft.

  3. Prediction of radiographic progression in synovitis-positive joints on maximum intensity projection of magnetic resonance imaging in rheumatoid arthritis.

    PubMed

    Akai, Takanori; Taniguchi, Daigo; Oda, Ryo; Asada, Maki; Toyama, Shogo; Tokunaga, Daisaku; Seno, Takahiro; Kawahito, Yutaka; Fujii, Yosuke; Ito, Hirotoshi; Fujiwara, Hiroyoshi; Kubo, Toshikazu

    2016-04-01

    Contrast-enhanced magnetic resonance imaging with maximum intensity projection (MRI-MIP) is an easy, useful imaging method to evaluate synovitis in rheumatoid hands. However, the prognosis of synovitis-positive joints on MRI-MIP has not been clarified. The aim of this study was to evaluate the relationship between synovitis visualized by MRI-MIP and joint destruction on X-rays in rheumatoid hands. The wrists, metacarpophalangeal (MP) joints, and proximal interphalangeal (PIP) joints of both hands (500 joints in total) were evaluated in 25 rheumatoid arthritis (RA) patients. Synovitis was scored from grade 0 to 2 on the MRI-MIP images. The Sharp/van der Heijde score and Larsen grade were used for radiographic evaluation. The relationships between the MIP score and the progression of radiographic scores and between the MIP score and bone marrow edema on MRI were analyzed using the trend test. As the MIP score increased, the Sharp/van der Heijde score and Larsen grade progressed severely. The rate of bone marrow edema-positive joints also increased with higher MIP scores. MRI-MIP imaging of RA hands is a clinically useful method that allows semi-quantitative evaluation of synovitis with ease and can be used to predict joint destruction. PMID:26861034

  4. A room-temperature phase transition in maximum microcline. Absorption in the far infrared (10 200 cm-1) in the temperature range 110 300 K

    NASA Astrophysics Data System (ADS)

    Wyncke, B.; McMillan, P. F.; Brown, W. L.; Openshaw, R. E.; Bréhat, F.

    1981-02-01

    The far infrared powder absorption spectra (10 200 cm-1) for a maximum microcline sample (obtained by ion-exchange from Amelia albite) and for a natural maximum microcline were measured at steps of 10 K on lowering and raising the temperature between 300 and 110 K. Of the absorption bands at 97.5, 113.5, 137.5, 148, and 157 cm-1 occurring at room temperature, those at 157 and eventually 148 cm-1 showed evidence of a phase transition and only that at 157 cm-1 showed hysteresis. The transition occurs at 245±5 K on lowering the temperature and the low-temperature form can be superheated to 300 K in the case of the ion-exchange sample. Oriented thin sections parallel to (001) and (010) were also measured to 110 K as a function of the direction of the electric vector E, but could not be unambiguously interpreted. Though the effect is very slight it is tentatively proposed that the phase transition (already characterized by calorimetry and lattice parameters) involves changes in K-O and T-O-T bonds.

  5. Effects of core position of locally resonant scatterers on low-frequency acoustic absorption in viscoelastic panel

    NASA Astrophysics Data System (ADS)

    Zhong, Jie; Wen, Ji-Hong; Zhao, Hong-Gang; Yin, Jian-Fei; Yang, Hai-Bin

    2015-08-01

    Locally resonant sonic materials, due to their ability to control the propagation of low-frequency elastic waves, have become a promising option for underwater sound absorption materials. In this paper, the finite element method is used to investigate the absorption characteristics of a viscoelastic panel periodically embedded with a type of infinite-long non-coaxially cylindrical locally resonant scatterers (LRSs). The effect of the core position in the coating layer of the LRS on the low-frequency (500 Hz-3000 Hz) sound absorption property is investigated. With increasing the longitudinal core eccentricity e, there occur few changes in the absorptance at the frequencies below 1500 Hz, however, the absorptance above 1500 Hz becomes gradually better and the valid absorption (with absorptance above 0.8) frequency band (VAFB) of the viscoelastic panel becomes accordingly broader. The absorption mechanism is revealed by using the displacement field maps of the viscoelastic panel and the steel slab. The results show two typical resonance modes. One is the overall resonance mode (ORM) caused by steel backing, and the other is the core resonance mode (CRM) caused by LRS. The absorptance of the viscoelastic panel by ORM is induced mainly by the vibration of the steel slab and affected little by core position. On the contrary, with increasing the core eccentricity, the CRM shifts toward high frequency band and decouples with the ORM, leading to two separate absorption peaks and the broadened VAFB of the panel. Project supported by the National Natural Science Foundation of China (Grant No. 51275519).

  6. Absorption of Low-Loss Optical Materials Measured at 1064 nm by a Position-Modulated Collinear Photothermal Detection Technique

    NASA Astrophysics Data System (ADS)

    Loriette, Vincent; Boccara, Claude

    2003-02-01

    A collinear photothermal detection bench is described that makes use of a position-modulated heating source instead of the classic power-modulated source. This new modulation scheme increases by almost a factor 2 the sensitivity of a standard mirage bench. This bench is then used to measure the absorption coefficient of OH-free synthetic fused silica at 1064 nm in the parts per 106 range, which, combined with spectrophotometric measurements, confirms that the dominant absorption source is the OH content.

  7. Absorption of low-loss optical materials measured at 1064 nm by a position-modulated collinear photothermal detection technique.

    PubMed

    Loriette, Vincent; Boccara, Claude

    2003-02-01

    A collinear photothermal detection bench is described that makes use of a position-modulated heating source instead of the classic power-modulated source. This new modulation scheme increases by almost a factor 2 the sensitivity of a standard mirage bench. This bench is then used to measure the absorption coefficient of OH-free synthetic fused silica at 1064 nm in the parts per 10(6) range, which, combined with spectrophotometric measurements, confirms that the dominant absorption source is the OH content. PMID:12564484

  8. Resonance lamp absorption technique for simultaneous determination of the OH concentration and temperature at 10 spatial positions in combustion environments

    NASA Technical Reports Server (NTRS)

    Shirinzadeh, B.; Gregory, Ray W.

    1994-01-01

    A rugged, easy to implement, line-of-sight absorption instrument which utilizes a low pressure water vapor microwave discharge cell as the light source, has been developed to make simultaneous measurements of the OH concentration and temperature at 10 spatial positions. The design, theory, and capability of the instrument are discussed. Results of the measurements obtained on a methane/air flat flame burner are compared with those obtained using a single-frequency, tunable dye laser system.

  9. Full-Quantum chemical calculation of the absorption maximum of bacteriorhodopsin: a comprehensive analysis of the amino acid residues contributing to the opsin shift

    PubMed Central

    Hayashi, Tomohiko; Matsuura, Azuma; Sato, Hiroyuki; Sakurai, Minoru

    2012-01-01

    Herein, the absorption maximum of bacteriorhodopsin (bR) is calculated using our recently developed method in which the whole protein can be treated quantum mechanically at the level of INDO/S-CIS//ONIOM (B3LYP/6-31G(d,p): AMBER). The full quantum mechanical calculation is shown to reproduce the so-called opsin shift of bR with an error of less than 0.04 eV. We also apply the same calculation for 226 different bR mutants, each of which was constructed by replacing any one of the amino acid residues of the wild-type bR with Gly. This substitution makes it possible to elucidate the extent to which each amino acid contributes to the opsin shift and to estimate the inter-residue synergistic effect. It was found that one of the most important contributions to the opsin shift is the electron transfer from Tyr185 to the chromophore upon excitation. We also indicate that some aromatic (Trp86, Trp182) and polar (Ser141, Thr142) residues, located in the vicinity of the retinal polyene chain and the β-ionone ring, respectively, play an important role in compensating for the large blue-shift induced by both the counterion residues (Asp85, Asp212) and an internal water molecule (W402) located near the Schiff base linkage. In particular, the effect of Trp86 is comparable to that of Tyr185. In addition, Ser141 and Thr142 were found to contribute to an increase in the dipole moment of bR in the excited state. Finally, we provide a complete energy diagram for the opsin shift together with the contribution of the chromophore-protein steric interaction. PMID:27493528

  10. Shallow-trap-induced positive absorptive two-beam coupling 'gain' and light-induced transparency in nominally undoped barium titanate

    NASA Technical Reports Server (NTRS)

    Garrett, M. H.; Tayebati, P.; Chang, J. Y.; Jenssen, H. P.; Warde, C.

    1992-01-01

    The asymmetry of beam coupling with respect to the orientation of the polar axis in a nominally undoped barium titanate crystal is used to determine the electro-optic and absorptive 'gain' in the usual beam-coupling geometry. For small grating wave vectors, the electrooptic coupling vanishes but the absorptive coupling remains finite and positive. Positive absorptive coupling at small grating wave vectors is correlated with the light-induced transparency of the crystal described herein. The intensity and grating wave vector dependence of the electrooptic and absorptive coupling, and the light-induced transparency are consistent with a model incorporating deep and shallow levels.

  11. Fabrication of controllable form submicrometer structures on positive photoresist by one-photon absorption direct laser writing technique

    NASA Astrophysics Data System (ADS)

    Tong, Quang Cong; Do, Minh Thanh; Journet, Bernard; Ledoux-Rak, Isabelle; Lai, Ngoc Diep

    2016-04-01

    We demonstrate a very simple and low-cost method based on one-photon absorption direct laser writing technique to fabricate arbitrary two-dimensional (2D) polymeric submicrometer structures with controllable form. In this technique, a continuous-wave green laser beam (532 nm) with very weak power is tightly focused into a positive photoresist (S1805) by a high numerical aperture (NA) objective lens (OL), depolymerizing the polymer in a local submicrometer region. The focusing spot is then moved in a controllable trajectory by a 3D piezo translation stage, resulting in desired structures. The low absorption effect of the photoresist at the excitation wavelength allows obtaining structures with submicrometer size and great depth. In particular, by controlling the exposure dose, e.g. the scanning speed, and the scanning configuration, the structures have been created in positive (cylindrical material in air) or negative (air holes) form. The 2D square structures with periods in between 0.6 μm and 1 μm and with a feature size of about 150 nm have been demonstrated with an OL of NA = 0.9 (air-immersion). The fabricated results are well consistent with those obtained numerically by using a vectorial diffraction theory for high NA OLs. This investigation should be very useful for fabrication of photonic and plasmonic templates.

  12. Assessment of Effective Ankle Joint Positioning in Strength Training for Intrinsic Foot Flexor Muscles: A Comparison of Intrinsic Foot Flexor Muscle Activity in a Position Intermediate to Plantar and Dorsiflexion with that in Maximum Plantar Flexion Using Needle Electromyography

    PubMed Central

    Hashimoto, Takayuki; Sakuraba, Keishoku

    2014-01-01

    [Purpose] The effectiveness of intrinsic foot flexor strength training performed in the plantar flexion position was examined using needle electromyography. [Subjects] The subjects of this study were 18 healthy men. [Methods] We used needle electromyography to measure the muscle activities of the flexor hallucis brevis (FHB), and the flexor digitorum brevis (FDB) in maximum plantar and an intermediate position. [Results] Significant increases in muscle activities were observed for both FHB and FDB, and the rates of increase from the intermediate position to the plantar flexion position were 43% for FHB and 46% for FDB. [Conclusion] This study demonstrated that it is possible to evaluate intrinsic foot flexors, in addition to the numerous reports on treatment methods focusing on extrinsic foot flexors. Furthermore, the results suggest that toe flexion exercises performed during plantar flexion of the ankle joint are an effective method for intrinsic foot flexor strength training. PMID:24707106

  13. The Fundamental Quadrupole Band of (14)N2: Line Positions from High-Resolution Stratospheric Solar Absorption Spectra

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Zander, R.; Goldman, A.; Murcray, F. J.; Murcray, D. G.; Grunson, M. R.; Farmer, C. B.

    1991-01-01

    The purpose of this note is to report accurate measurements of the positions of O- and S-branch lines of the (1-0) vibration-rotation quadrupole band of molecular nitrogen ((14)N2) and improved Dunham coefficients derived from a simultaneous least-squares analysis of these measurements and selected infrared and far infrared data taken from the literature. The new measurements have been derived from stratospheric solar occultation spectra recorded with Fourier transform spectrometer (FTS) instruments operated at unapodized spectral resolutions of 0.002 and 0.01 /cm. The motivation for the present investigation is the need for improved N2 line parameters for use in IR atmospheric remote sensing investigations. The S branch of the N2 (1-0) quadrupole band is ideal for calibrating the line-of-sight airmasses of atmospheric spectra since the strongest lines are well placed in an atmospheric window, their absorption is relatively insensitive to temperature and is moderately strong (typical line center depths of 10 to 50% in high-resolution ground-based solar spectra and in lower stratospheric solar occultation spectra), and the volume mixing ratio of nitrogen is constant in the atmosphere and well known. However, a recent investigation has'shown the need to improve the accuracies of the N2 fine positions, intensities, air-broadened half-widths, and their temperature dependences to fully exploit this calibration capability (1). The present investigation addresses the problem of improving the accuracy of the N2 line positions.

  14. Influence of Welding Current and Focal Position on the Resonant Absorption of Laser Radiation in a TIG Welding Arc

    NASA Astrophysics Data System (ADS)

    Emde, B.; Huse, M.; Hermsdorf, J.; Kaierle, S.; Wesling, V.; Overmeyer, L.

    The work presents the influence of welding current and focal position on the resonant absorption of diode laser radiation in a TIG welding arc. The laser beam is guided perpendicular to the electrical arc to avoid an interaction with the electrodes. Laser power measurements have shown a reduction of the measured laser power up to 18% after passing the electrical arc. This reduction results from the interaction of argon shielding gas atoms and laser radiation at 810.4 nm and 811.5 nm. The interaction is strongly affected by the adjusted welding current and the adjustment of the laser beam and the electrical arc. Lowering the welding current or shifting the laser beam out of the centerline of the electrical arc reduces the ionization probability. An increased ionization is necessary to decrease the resistance of the electrical arc.

  15. Positioning.

    ERIC Educational Resources Information Center

    Conone, Ruth M.

    The key to positioning is the creation of a clear benefit image in the consumer's mind. One positioning strategy is creating in the prospect's mind a position that takes into consideration the company's or agency's strengths and weaknesses as well as those of its competitors. Another strategy is to gain entry into a position ladder owned by…

  16. Maximum Jailbreak

    NASA Astrophysics Data System (ADS)

    Singleton, B.

    First formulated one hundred and fifty years ago by the heretical scholar Nikolai Federov, the doctrine of cosmism begins with an absolute refusal to treat the most basic factors conditioning life on Earth ­ gravity and death ­ as necessary constraints on action. As manifest through the intoxicated cheers of its early advocates that humans should storm the heavens and conquer death, cosmism's foundational gesture was to conceive of the earth as a trap. Its duty was therefore to understand the duty of philosophy, economics and design to be the creation of means to escape it. This could be regarded as a jailbreak at the maximum possible scale, a heist in which the human species could steal itself from the vault of the Earth. After several decades of relative disinterest new space ventures are inspiring scientific, technological and popular imaginations, this essay explores what kind of cosmism might be constructed today. In this paper cosmism's position as a means of escape is both reviewed and evaluated by reflecting on the potential of technology that actually can help us achieve its aims and also through the lens and state-ofthe-art philosophy of accelerationism, which seeks to outrun modern tropes by intensifying them.

  17. Performance of a four-element Si drift detector for X-ray absorption fine-structure spectroscopy: resolution, maximum count rate, and dead-time correction with incorporation into the ATHENA data analysis software

    SciTech Connect

    Woicik, J.C.; Newburgh, W.; Ravel, B.; Fischer, D.A.

    2010-03-09

    The performance of a four-element Si drift detector for energy-dispersive fluorescence-yield X-ray absorption fine-structure measurements is reported, operating at the National Institute of Standards and Technology beamline X23A2 at the National Synchrotron Light Source. The detector can acquire X-ray absorption fine-structure spectra with a throughput exceeding 4 x 10{sup 5} counts per second per detector element (>1.6 x 10{sup 6} total counts per second summed over all four channels). At this count rate the resolution at 6 keV is approximately 220 eV, which adequately resolves the Mn K{sub {alpha}} and K{sup {beta}} fluorescence lines. Accurate dead-time correction is demonstrated, and it has been incorporated into the ATHENA data analysis program. To maintain counting efficiency and high signal to background, it is suggested that the incoming count rate should not exceed {approx}70% of the maximum throughput.

  18. The influence of morphine on the absorption of paracetamol from various formulations in subjects in the supine position, as assessed by TDx measurement of salivary paracetamol concentrations.

    PubMed

    Kennedy, Julia M; Tyers, Nicola M; Davey, Andrew K

    2003-10-01

    The aim of this study was to determine the influence of the type of paracetamol formulation on the rate of absorption when subjects are in the supine position, with or without taking concomitant morphine. Two groups of healthy volunteers were used, who were in the fasting state and remained in the supine position during the study. One group took 1,500 mg of paracetamol on three occasions as conventional tablets, dispersible tablets or a suspension in a randomized crossover design. Seventeen saliva samples per subject were obtained (time zero to 360 min post-dose), which were then centrifuged and kept at -20 degrees C prior to analysis. The second group repeated the study following four doses of morphine syrup (10 mg 4 hourly) in the 12 h preceding paracetamol ingestion. In this phase of the study, paracetamol absorption from suspension was not investigated. A TDx assay was used to determine salivary paracetamol concentrations. The tmax for conventional tablets when taken concomitantly with morphine was 160 (+/- 81) min compared to 51 (+/- 58) min for subjects not taking morphine. For dispersible tablets the tmax in the morphine group was 14 (+/- 9) min compared to 15 (+/- 12) min without morphine. The results suggest that patients who are confined to bed and taking morphine will have an unacceptably long delay between taking conventional paracetamol tablets and the paracetamol reaching therapeutic plasma concentrations. Conversely, there is little effect on the absorption of dispersible paracetamol under the same conditions. PMID:14607015

  19. THE FAR-ULTRAVIOLET 'CONTINUUM' IN PROTOPLANETARY DISK SYSTEMS. II. CARBON MONOXIDE FOURTH POSITIVE EMISSION AND ABSORPTION

    SciTech Connect

    France, Kevin; Schindhelm, Eric; Burgh, Eric B.; Brown, Alexander; Green, James C.; Herczeg, Gregory J.; Brown, Joanna M.; Harper, Graham M.; Linsky, Jeffrey L.; Yang Hao; Abgrall, Herve; Ardila, David R.; Bergin, Edwin; Bethell, Thomas; Calvet, Nuria; Ingleby, Laura; Espaillat, Catherine; Gregory, Scott G.; Hillenbrand, Lynne A.; Hussain, Gaitee

    2011-06-10

    We exploit the high sensitivity and moderate spectral resolution of the Hubble Space Telescope Cosmic Origins Spectrograph to detect far-ultraviolet (UV) spectral features of carbon monoxide (CO) present in the inner regions of protoplanetary disks for the first time. We present spectra of the classical T Tauri stars HN Tau, RECX-11, and V4046 Sgr, representative of a range of CO radiative processes. HN Tau shows CO bands in absorption against the accretion continuum. The CO absorption most likely arises in warm inner disk gas. We measure a CO column density and rotational excitation temperature of N(CO) = (2 {+-} 1) x 10{sup 17} cm{sup -2} and T{sub rot}(CO) 500 {+-} 200 K for the absorbing gas. We also detect CO A-X band emission in RECX-11 and V4046 Sgr, excited by UV line photons, predominantly H I Ly{alpha}. All three objects show emission from CO bands at {lambda} > 1560 A, which may be excited by a combination of UV photons and collisions with non-thermal electrons. In previous observations these emission processes were not accounted for due to blending with emission from the accretion shock, collisionally excited H{sub 2}, and photo-excited H{sub 2}, all of which appeared as a 'continuum' whose components could not be separated. The CO emission spectrum is strongly dependent upon the shape of the incident stellar Ly{alpha} emission profile. We find CO parameters in the range: N(CO) {approx} 10{sup 18}-10{sup 19} cm{sup -2}, T{sub rot}(CO) {approx}> 300 K for the Ly{alpha}-pumped emission. We combine these results with recent work on photo-excited and collisionally excited H{sub 2} emission, concluding that the observations of UV-emitting CO and H{sub 2} are consistent with a common spatial origin. We suggest that the CO/H{sub 2} ratio ({identical_to} N(CO)/N(H{sub 2})) in the inner disk is {approx}1, a transition between the much lower interstellar value and the higher value observed in solar system comets today, a result that will require future

  20. Hubble Space Telescope faint object spectrograph Quasar Absorption System Snapshot Survey (AbSnap). 1: Astrometric optical positions and finding charts of 269 bright QSO

    NASA Technical Reports Server (NTRS)

    Bowen, David V.; Osmer, Samantha J.; Blades, J. Chris; Tytler, David; Cottrell, Lance; Fan, Xiao-Ming; Lanzetta, Kenneth M.

    1994-01-01

    We present finding charts and optical positions accurate to less than 1 arcsec for 269 bright (V less than or = 18.5) Quasi-Stellar Objects (QSOs). These objects were selected as candidates for the Hubble Space Telescope (HST) Quasar Absorption System Snapshot Survey (AbSnap), a program designed to use the Faint Object Spectrograph (FOS) to obtain short exposure ultraviolet (UV) spectra of bright QSOs. Many quasars were included because of their proximity to bright, low redshift galaxies and positions of these QSOs are measured accurately for the first time. Data were obtained using the digitized sky survey produced by the Space Telescope Science Institute's Guide Stars Selection System Astrometric Support Program.

  1. Responses of ocean circulation and carbon cycle to changes in the position of the Southern Hemisphere westerlies at Last Glacial Maximum

    PubMed Central

    Völker, Christoph; Köhler, Peter

    2013-01-01

    We explore the impact of a latitudinal shift in the westerly wind belt over the Southern Ocean on the Atlantic meridional overturning circulation (AMOC) and on the carbon cycle for Last Glacial Maximum background conditions using a state-of-the-art ocean general circulation model. We find that a southward (northward) shift in the westerly winds leads to an intensification (weakening) of no more than 10% of the AMOC. This response of the ocean physics to shifting winds agrees with other studies starting from preindustrial background climate, but the responsible processes are different. In our setup changes in AMOC seemed to be more pulled by upwelling in the south than pushed by downwelling in the north, opposite to what previous studies with different background climate are suggesting. The net effects of the changes in ocean circulation lead to a rise in atmospheric pCO2 of less than 10 μatm for both northward and southward shift in the winds. For northward shifted winds the zone of upwelling of carbon- and nutrient-rich waters in the Southern Ocean is expanded, leading to more CO2outgassing to the atmosphere but also to an enhanced biological pump in the subpolar region. For southward shifted winds the upwelling region contracts around Antarctica, leading to less nutrient export northward and thus a weakening of the biological pump. These model results do not support the idea that shifts in the westerly wind belt play a dominant role in coupling atmospheric CO2 rise and Antarctic temperature during deglaciation suggested by the ice core data. PMID:26074663

  2. Absorption and emission in defective cholesteric liquid crystal cells

    NASA Astrophysics Data System (ADS)

    Gevorgyan, A. H.; Harutyunyan, M. Z.; Matinyan, G. K.; Oganesyan, K. B.; Rostovtsev, Yu V.; Kurizki, G.; Scully, M. O.

    2016-04-01

    We investigated peculiarities of absorption, emission and photonic density of states of a cholesteric liquid crystal with an isotropic defect layer inside. The influence of the defect layer position on absorption and emission in the system was studied. It was shown that for non-diffracting circularly polarized incident light absorption/emission is maximum if the defect is in the centre of the system; and for diffracting circularly polarized incident light absorption/emission is maximum if the defect is shifted from the centre of the system to its left border from where light is incident. We also investigated influence of the defect layer thickness and those parameters which characterize loss and gain on absorption and emission. The influence of anisotropic absorption in the cholesteric liquid crystal layer on photonic density states was investigated, too.

  3. Petawatt laser absorption bounded

    PubMed Central

    Levy, Matthew C.; Wilks, Scott C.; Tabak, Max; Libby, Stephen B.; Baring, Matthew G.

    2014-01-01

    The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. Here using a relativistic Rankine-Hugoniot-like analysis, we show for the first time that f exhibits a theoretical maximum and minimum. These bounds constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials. PMID:24938656

  4. Petawatt laser absorption bounded

    NASA Astrophysics Data System (ADS)

    Levy, Matthew C.; Wilks, Scott C.; Tabak, Max; Libby, Stephen B.; Baring, Matthew G.

    2014-06-01

    The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. Here using a relativistic Rankine-Hugoniot-like analysis, we show for the first time that f exhibits a theoretical maximum and minimum. These bounds constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials.

  5. Absorption heat pump system

    DOEpatents

    Grossman, Gershon

    1984-01-01

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  6. Absorption heat pump system

    DOEpatents

    Grossman, G.

    1982-06-16

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  7. Maximum power tracking

    SciTech Connect

    O'Sullivan, G.

    1983-03-01

    By definition, a maximum power tracking device causes the photovoltaic array to operate on the locus of maximum power points within a specified accuracy. There are limitations to the application of maximum power tracking. A prerequisite is that the load be capable of absorbing all of the power availble at all times. Battery chargers, electrical heaters, water pumps, and most significantly, returning power to the utility grid, are prime examples of applications that are adaptable to maximum power tracking. Maximum power tracking is available to either dc or ac loads. An inverter equipped with a means of changing input voltage by controlling its input impedance can deliver maximum power to ac loads. The inverter can be fixed or variable frequency and fixed or variable voltage, but must be compatible with the ac load. The discussion includes applications, techniques, and cost factors.

  8. Maximum thrust mode evaluation

    NASA Technical Reports Server (NTRS)

    Orme, John S.; Nobbs, Steven G.

    1995-01-01

    Measured reductions in acceleration times which resulted from the application of the F-15 performance seeking control (PSC) maximum thrust mode during the dual-engine test phase is presented as a function of power setting and flight condition. Data were collected at altitudes of 30,000 and 45,000 feet at military and maximum afterburning power settings. The time savings for the supersonic acceleration is less than at subsonic Mach numbers because of the increased modeling and control complexity. In addition, the propulsion system was designed to be optimized at the mid supersonic Mach number range. Recall that even though the engine is at maximum afterburner, PSC does not trim the afterburner for the maximum thrust mode. Subsonically at military power, time to accelerate from Mach 0.6 to 0.95 was cut by between 6 and 8 percent with a single engine application of PSC, and over 14 percent when both engines were optimized. At maximum afterburner, the level of thrust increases were similar in magnitude to the military power results, but because of higher thrust levels at maximum afterburner and higher aircraft drag at supersonic Mach numbers the percentage thrust increase and time to accelerate was less than for the supersonic accelerations. Savings in time to accelerate supersonically at maximum afterburner ranged from 4 to 7 percent. In general, the maximum thrust mode has performed well, demonstrating significant thrust increases at military and maximum afterburner power. Increases of up to 15 percent at typical combat-type flight conditions were identified. Thrust increases of this magnitude could be useful in a combat situation.

  9. Cholesterol absorption.

    PubMed

    Ostlund, Richard E

    2002-03-01

    Cholesterol absorption is a key regulatory point in human lipid metabolism because it determines the amount of endogenous biliary as well as dietary cholesterol that is retained, thereby influencing whole body cholesterol balance. Plant sterols (phytosterols) and the drug ezetimibe reduce cholesterol absorption and low-density lipoprotein cholesterol in clinical trials, complementing the statin drugs, which inhibit cholesterol biosynthesis. The mechanism of cholesterol absorption is not completely known but involves the genes ABC1, ABCG5, and ABCG8, which are members of the ATP-binding cassette protein family and appear to remove unwanted cholesterol and phytosterols from the enterocyte. ABC1 is upregulated by the liver X (LXR) and retinoid X (RXR) nuclear receptors. Acylcholesterol acytransferase-2 is an intestinal enzyme that esterifies absorbed cholesterol and increases cholesterol absorption when dietary intake is high. New clinical treatments based on better understanding of absorption physiology are likely to substantially improve clinical cholesterol management in the future. PMID:17033296

  10. Photodynamic cancer therapy: fluorescence localization and light absorption spectra of chlorophyll-derived photosensitizers inside cancer cells

    NASA Astrophysics Data System (ADS)

    Moser, Joerg G.; Rueck, Angelika C.; Schwarzmaier, Hans-Joachim; Westphal-Frosch, Christel

    1992-07-01

    The first prerequisite for an optimum effect of photodynamic therapy with chlorophyll- derived photosensitizers is irradiation at the S1 absorption maximum in the red spectral region. This absorption maximum changes its position due to molecular association by 20 to 100 nm depending on the subcellular environment, and must be determined by direct absorption spectrometry in the region of subcellular sensitizer localization. Fluorescence- intensifying video microscopy allows for localization of the sensitizer storage site at or near the Galgi apparatus of OAT 75 small-cell lung carcinoma cells. The absorption maximum at 760 nm taken from spectra of single cells and cell layers determines the postulated optimum condition for dye laser irradiation with bacteriopheophorbide-a-methyl-ester as the sensitizer.

  11. Binary TLBO algorithm assisted for designing plasmonic nano bi-pyramids-based absorption coefficient

    NASA Astrophysics Data System (ADS)

    Akhlaghi, Majid; Emami, Farzin; Nozhat, Najmeh

    2014-07-01

    A new efficient binary optimization method based on Teaching-Learning-Based Optimization (TLBO) algorithm is proposed to design an array of plasmonic nano bi-pyramids in order to achieve maximum absorption coefficient spectrum. In binary TLBO, a group of learners consisting of a matrix with binary entries controls the presence ('1') or the absence ('0') of nanoparticles in the array. Simulation results show that absorption coefficient strongly depends on the localized position of plasmonic nanoparticles. Non-periodic structures have more appropriate response in term of absorption coefficient. This approach is useful in optical applications such as solar cells and plasmonic nano antenna.

  12. Petawatt laser absorption bounded

    NASA Astrophysics Data System (ADS)

    Levy, Matthew; Wilks, Scott; Tabak, Max; Libby, Stephen; Baring, Matthew

    2014-10-01

    The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top relativistic particle accelerators, ultrafast charged particle imaging systems and fast ignition inertial confinement fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. In this presentation, using a relativistic Rankine-Hugoniot-like analysis, we show how to derive the theoretical maximum and minimum of f. These boundaries constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. Close agreement is shown with several dozens of published experimental data points and simulation results, helping to confirm the theory. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials.

  13. Role of beam absorption in plasma during laser welding

    SciTech Connect

    SEMAK,V.V.; STEELE,R.J.; FUERSCHBACH,PHILLIP W.; DAMKROGER,BRIAN K.

    2000-05-15

    The relationship between beam focus position and penetration depth in CW laser welding was studied numerically and experimentally for different welding conditions. Calculations were performed using a transient hydrodynamic model that incorporates the effect of evaporation recoil pressure and the associated melt expulsion. The simulation results are compared with measurements made on a series of test welds obtained using a 1650 W CO{sub 2} laser. The simulations predict, and the experiments confirm, that maximum penetration occurs with a specific location of the beam focus, with respect to the original sample surface, and that this relationship depends on the processing conditions. In particular, beam absorption in the plasma has a significant effect on the relationship between penetration and focus position. When the process parameters result in strong beam absorption in the keyhole plasma, the maximum penetration will occur when the laser focus is at or above the sample surface. In a case of weak absorption however, the penetration depth reaches its maximum value when the beam focus is located below the sample surface. In all cases, the numerical results are in good agreement with the experimental measurements.

  14. Microwave absorption properties of Ni/(C, silicides) nanocapsules

    PubMed Central

    2012-01-01

    The microwave absorption properties of Ni/(C, silicides) nanocapsules prepared by an arc discharge method have been studied. The composition and the microstructure of the Ni/(C, silicides) nanocapsules were determined by means of X-ray diffraction, X-ray photoelectric spectroscopy, and transmission electron microscope observations. Silicides, in the forms of SiOx and SiC, mainly exist in the shells of the nanocapsules and result in a large amount of defects at the ‘core/shell’ interfaces as well as in the shells. The complex permittivity and microwave absorption properties of the Ni/(C, silicides) nanocapsules are improved by the doped silicides. Compared with those of Ni/C nanocapsules, the positions of maximum absorption peaks of the Ni/(C, silicides) nanocapsules exhibit large red shifts. An electric dipole model is proposed to explain this red shift phenomenon. PMID:22548846

  15. Ultraviolet absorption and luminescence of matrix-isolated adenine

    SciTech Connect

    Polewski, K.; Sutherland, J.; Zinger, D.; Trunk, J.

    2011-10-01

    We have investigated the absorption, the fluorescence and phosphorescence emission and the fluorescence lifetimes of adenine in low-temperature argon and nitrogen matrices at 15 K. Compared to other environments the absorption spectrum shows higher intensity at the shortest wavelengths, and a weak apparent absorption peak is observed at 280 nm. The resolved fluorescence excitation spectrum has five peaks at positions corresponding to those observed in the absorption spectrum. The position of the fluorescence maximum depends on the excitation wavelength. Excitation below 220 nm displays a fluorescence maximum at 305 nm, while for excitations at higher wavelengths the maximum occurs at 335 nm. The results suggest that multiple-emission excited electronic states are populated in low-temperature gas matrices. Excitation at 265 nm produces a phosphorescence spectrum with a well-resolved vibrational structure and a maximum at 415 nm. The fluorescence decays corresponding to excitation at increasing energy of each resolved band could be fit with a double exponential, with the shorter and longer lifetimes ranging from 1.7 to 3.3 ns and from 12 to 23 ns, respectively. Only for the excitation at 180 nm one exponential is required, with the calculated lifetimes of 3.3 ns. The presented results provide an experimental evidence of the existence of multiple site-selected excited electronic states, and may help elucidate the possible deexcitation pathways of adenine. The additional application of synchrotron radiation proved to result in a significant enhancement of the resolution and spectral range of the phenomena under investigation.

  16. Maximum mixing method

    NASA Astrophysics Data System (ADS)

    Hjorth, Jens

    The unique feature of MEM is that C(-1)(z) = exp(z) amplifies all scales equally. Narayan & Nityananda (1986) have shown that this leads to Gaussian deconvolved peaks. In MMM different scales are treated differently, depending on the choice of C. This gives different peak shapes, but also allows one to experiment with the degree of peak sharpening as a function of peak height. In fact, despite its strong information-theoretic background, MEM is known to redistribute flux incorrectly during deconvolution, thus making the method problematic if the goal is to get correct intensities out. MMM could remedy this problem by using an alternative to the entropy. In conclusion, some ideas connecting the physics of blurring with a proposed reconstruction scheme, dubbed Maximum Mixing Method, have been presented. It has been shown that this physically motivated, non-information theoretic, non-probabilistic, non-Bayesian approach can be turned into a powerful deconvolution technique, competitive with, and having as a special case, the Maximum Entropy Method. Further work within the proposed framework is required to fully explore the consequences of the theory. A paper including proofs and examples is in preparation.

  17. Chaotic Systems with Absorption

    NASA Astrophysics Data System (ADS)

    Altmann, Eduardo G.; Portela, Jefferson S. E.; Tél, Tamás

    2013-10-01

    Motivated by applications in optics and acoustics we develop a dynamical-system approach to describe absorption in chaotic systems. We introduce an operator formalism from which we obtain (i) a general formula for the escape rate κ in terms of the natural conditionally invariant measure of the system, (ii) an increased multifractality when compared to the spectrum of dimensions Dq obtained without taking absorption and return times into account, and (iii) a generalization of the Kantz-Grassberger formula that expresses D1 in terms of κ, the positive Lyapunov exponent, the average return time, and a new quantity, the reflection rate. Simulations in the cardioid billiard confirm these results.

  18. On the role of spatial position of bridged oxygen atoms as surface passivants on the ground-state gap and photo-absorption spectrum of silicon nano-crystals

    SciTech Connect

    Nazemi, Sanaz; Soleimani, Ebrahim Asl; Pourfath, Mahdi E-mail: pourfath@iue.tuwien.ac.at

    2015-11-28

    Silicon nano-crystals (NCs) are potential candidates for enhancing and tuning optical properties of silicon for optoelectronic and photo-voltaic applications. Due to the high surface-to-volume ratio, however, optical properties of NC result from the interplay of quantum confinement and surface effects. In this work, we show that both the spatial position of surface terminants and their relative positions have strong effects on NC properties as well. This is accomplished by investigating the ground-state HOMO-LUMO band-gap, the photo-absorption spectra, and the localization and overlap of HOMO and LUMO orbital densities for prototype ∼1.2 nm Si{sub 32–x}H{sub 42–2x}O{sub x} hydrogenated silicon NC with bridged oxygen atoms as surface terminations. It is demonstrated that the surface passivation geometry significantly alters the localization center and thus the overlap of frontier molecular orbitals, which correspondingly modifies the electronic and optical properties of NC.

  19. Optical absorption analysis and optimization of gold nanoshells.

    PubMed

    Tuersun, Paerhatijiang; Han, Xiang'e

    2013-02-20

    Gold nanoshells, consisting of a nanoscale dielectric core coated with an ultrathin gold shell, have wide biomedical applications due to their strong optical absorption properties. Gold nanoshells with high absorption efficiencies can help to improve these applications. We investigate the effects of the core material, surrounding medium, core radius, and shell thickness on the absorption spectra of gold nanoshells by using the light-scattering theory of a coated sphere. Our results show that the position and intensity of the absorption peak can be tuned over a wide range by manipulating the above-mentioned parameters. We also obtain the optimal absorption efficiencies and structures of hollow gold nanoshells and gold-coated SiO(2) nanoshells embedded in water at wavelengths of 800, 820, and 1064 nm. The results show that hollow gold nanoshells possess the maximum absorption efficiency (5.42) at a wavelength of 800 nm; the corresponding shell thickness and core radius are 4.8 and 38.9 nm, respectively. They can be used as the ideal photothermal conversation particles for biomedical applications. PMID:23435006

  20. Ultraviolet absorption spectrum of HOCl

    NASA Technical Reports Server (NTRS)

    Burkholder, James B.

    1993-01-01

    The room temperature UV absorption spectrum of HOCl was measured over the wavelength range 200 to 380 nm with a diode array spectrometer. The absorption spectrum was identified from UV absorption spectra recorded following UV photolysis of equilibrium mixtures of Cl2O/H2O/HOCl. The HOCl spectrum is continuous with a maximum at 242 nm and a secondary peak at 304 nm. The measured absorption cross section at 242 nm was (2.1 +/- 0.3) x 10 exp -19/sq cm (2 sigma error limits). These results are in excellent agreement with the work of Knauth et al. (1979) but in poor agreement with the more recent measurements of Mishalanie et al. (1986) and Permien et al. (1988). An HOCl nu2 infrared band intensity of 230 +/- 35/sq cm atm was determined based on this UV absorption cross section. The present results are compared with these previous measurements and the discrepancies are discussed.

  1. Maximum bow force revisited.

    PubMed

    Mores, Robert

    2016-08-01

    Schelleng [J. Acoust. Soc. Am. 53, 26-41 (1973)], Askenfelt [J. Acoust. Soc. Am. 86, 503-516 (1989)], Schumacher [J. Acoust. Soc. Am. 96, 1985-1998 (1994)], and Schoonderwaldt, Guettler, and Askenfelt [Acta Acust. Acust. 94, 604-622 (2008)] formulated-in different ways-how the maximum bow force relates to bow velocity, bow-bridge distance, string impedance, and friction coefficients. Issues of uncertainty are how to account for friction or for the rotational admittance of the strings. Related measurements at the respective transitions between regimes of Helmholtz motion and non-Helmholtz motion employ a variety of bowing machines and stringed instruments. The related findings include all necessary parameters except the friction coefficients, leaving the underlying models unconfirmed. Here, a bowing pendulum has been constructed which allows precise measurement of relevant bowing parameters, including the friction coefficients. Two cellos are measured across all strings for three different bow-bridge distances. The empirical data suggest that-taking the diverse elements of existing models as options-Schelleng's model combined with Schumacher's velocity term yields the best fit. Furthermore, the pendulum employs a bow driving mechanism with adaptive impedance which discloses that mentioned regimes are stable and transitions between them sometimes require a hysteresis on related parameters. PMID:27586745

  2. Generalized Maximum Entropy

    NASA Technical Reports Server (NTRS)

    Cheeseman, Peter; Stutz, John

    2005-01-01

    A long standing mystery in using Maximum Entropy (MaxEnt) is how to deal with constraints whose values are uncertain. This situation arises when constraint values are estimated from data, because of finite sample sizes. One approach to this problem, advocated by E.T. Jaynes [1], is to ignore this uncertainty, and treat the empirically observed values as exact. We refer to this as the classic MaxEnt approach. Classic MaxEnt gives point probabilities (subject to the given constraints), rather than probability densities. We develop an alternative approach that assumes that the uncertain constraint values are represented by a probability density {e.g: a Gaussian), and this uncertainty yields a MaxEnt posterior probability density. That is, the classic MaxEnt point probabilities are regarded as a multidimensional function of the given constraint values, and uncertainty on these values is transmitted through the MaxEnt function to give uncertainty over the MaXEnt probabilities. We illustrate this approach by explicitly calculating the generalized MaxEnt density for a simple but common case, then show how this can be extended numerically to the general case. This paper expands the generalized MaxEnt concept introduced in a previous paper [3].

  3. Absorption driven focus shift

    NASA Astrophysics Data System (ADS)

    Harrop, N.; Wolf, S.; Maerten, O.; Dudek, K.; Ballach, S.; Kramer, R.

    2016-03-01

    Modern high brilliance near infrared lasers have seen a tremendous growth in applications throughout the world. Increased productivity has been achieved by higher laser power and increased brilliance of lasers. Positive impacts on the performance and costs of parts are opposed to threats on process stability and quality, namely shift of focus position over time. A high initial process quality will be reduced by contamination of optics, eventually leading to a focus shift or even destruction of the optics. Focus analysis at full power of multi-kilowatt high brilliance lasers is a very demanding task because of high power densities in the spot and the high power load on optical elements. With the newly developed high power projection optics, the High-Power Micro-Spot Monitor High Brilliance (HP-MSM-HB) is able to measure focus diameter as low as 20 μm at power levels up to 10 kW at very low internal focus shift. A main driving factor behind thermally induced focus shift is the absorption level of the optical element. A newly developed measuring system is designed to determine the relative absorption level in reference to a gold standard. Test results presented show a direct correlation between absorption levels and focus shift. The ability to determine the absorption level of optical elements as well as their performance at full processing power before they are put to use, enables a high level of quality assurance for optics manufacturers and processing head manufacturers alike.

  4. Combined Electron Paramagnetic Resonance and Atomic Absorption Spectroscopy/Inductively Coupled Plasma Analysis As Diagnostics for Soluble Manganese Species from Mn-Based Positive Electrode Materials in Li-ion Cells.

    PubMed

    Shilina, Yuliya; Ziv, Baruch; Meir, Aviv; Banerjee, Anjan; Ruthstein, Sharon; Luski, Shalom; Aurbach, Doron; Halalay, Ion C

    2016-04-19

    Manganese dissolution from positive electrodes significantly reduces the durability of lithium-ion batteries. Knowledge of dissolution rates and oxidation states of manganese ions is essential for designing effective mitigation measures for this problem. We show that electron paramagnetic resonance (EPR) combined with atomic absorption spectroscopy (AAS) or inductively coupled plasma (ICP) can determine both manganese dissolution rates and relative Mn(3+) amounts, by comparing the correlation between EPR and AAS/ICP data for Mn(2+) standards with that for samples containing manganese cations dissolved from active materials (LiMn2O4 (LMO) and LiNi0.5Mn1.5O4 (LNMO)) into the same electrolyte solution. We show that Mn(3+), and not Mn(2+), is the dominant species dissolved from LMO, while Mn(2+) is predominant for LNMO. Although the dissolution rate of LMO varies significantly for the two investigated materials, due to particle morphology and the presence of Cr in one of them, the Mn speciation appears independent of such details. Thus, the relative abundance of dissolved manganese ions in various oxidation states depends mainly on the overall chemical identity of the active material (LMO vs LNMO). We demonstrate the relevance of our methodology for practical batteries with data for graphite-LMO cells after high-temperature cycling or stand at 4.2 V. PMID:27018717

  5. Cell Development obeys Maximum Fisher Information

    PubMed Central

    Frieden, B. Roy; Gatenby, Robert A.

    2014-01-01

    Eukaryotic cell development has been optimized by natural selection to obey maximal intracellular flux of messenger proteins. This, in turn, implies maximum Fisher information on angular position about a target nuclear pore complex (NPR). The cell is simply modeled as spherical, with cell membrane (CM) diameter 10μm and concentric nuclear membrane (NM) diameter 6μm. The NM contains ≈ 3000 nuclear pore complexes (NPCs). Development requires messenger ligands to travel from the CM-NPC-DNA target binding sites. Ligands acquire negative charge by phosphorylation, passing through the cytoplasm over Newtonian trajectories toward positively charged NPCs (utilizing positive nuclear localization sequences). The CM-NPC channel obeys maximized mean protein flux F and Fisher information I at the NPC, with first-order δI = 0 and approximate 2nd-order δ2I ≈ 0 stability to environmental perturbations. Many of its predictions are confirmed, including the dominance of protein pathways of from 1–4 proteins, a 4nm size for the EGFR protein and the flux value F ≈1016 proteins/m2-s. After entering the nucleus, each protein ultimately delivers its ligand information to a DNA target site with maximum probability, i.e. maximum Kullback-Liebler entropy HKL. In a smoothness limit HKL → IDNA/2, so that the total CM-NPC-DNA channel obeys maximum Fisher I. Thus maximum information → non-equilibrium, one condition for life. PMID:23747917

  6. Maximum hyperchaos in chaotic nonmonotonic neuronal networks

    NASA Astrophysics Data System (ADS)

    Shuai, J. W.; Chen, Z. X.; Liu, R. T.; Wu, B. X.

    1997-07-01

    Hyperchaos in chaotic nonmonotonic neuronal networks is discussed with computer simulations. Maximum chaos with all Lyapunov exponents positive is found not only in the present dissipative model with weak coupling connections between neurons, but also with some strong-coupling connections. Although the model presented is a noninvertible map, the information dimension of simple chaos still yields a good approximation to the Lyapunov dimension.

  7. ABSORPTION ANALYZER

    DOEpatents

    Brooksbank, W.A. Jr.; Leddicotte, G.W.; Strain, J.E.; Hendon, H.H. Jr.

    1961-11-14

    A means was developed for continuously computing and indicating the isotopic assay of a process solution and for automatically controlling the process output of isotope separation equipment to provide a continuous output of the desired isotopic ratio. A counter tube is surrounded with a sample to be analyzed so that the tube is exactly in the center of the sample. A source of fast neutrons is provided and is spaced from the sample. The neutrons from the source are thermalized by causing them to pass through a neutron moderator, and the neutrons are allowed to diffuse radially through the sample to actuate the counter. A reference counter in a known sample of pure solvent is also actuated by the thermal neutrons from the neutron source. The number of neutrons which actuate the detectors is a function of a concentration of the elements in solution and their neutron absorption cross sections. The pulses produced by the detectors responsive to each neu tron passing therethrough are amplified and counted. The respective times required to accumulate a selected number of counts are measured by associated timing devices. The concentration of a particular element in solution may be determined by utilizing the following relation: T2/Ti = BCR, where B is a constant proportional to the absorption cross sections, T2 is the time of count collection for the unknown solution, Ti is the time of count collection for the pure solvent, R is the isotopic ratlo, and C is the molar concentration of the element to be determined. Knowing the slope constant B for any element and when the chemical concentration is known, the isotopic concentration may be readily determined, and conversely when the isotopic ratio is known, the chemical concentrations may be determined. (AEC)

  8. Effect of impurity on the absorption of a parabolic quantum dot with including Rashba spin-orbit interaction

    NASA Astrophysics Data System (ADS)

    Hosseinpour, Parinaz; Soltani-Vala, Ali; Barvestani, Jamal

    2016-06-01

    In this paper, the influence of impurity parameters on the electron energy spectrum and absorption coefficients in a parabolic quantum dot and in the presence of Rashba spin-orbit interaction subjected to a perpendicular magnetic field is studied. The impurity potential is approximated by a Gaussian form. We have shown that in the both cases of a repulsive and attractive Gaussian impurity, the absorption coefficients are strongly affected by the decay length. These coefficients show blue (red) shift as the decay length of repulsive (attractive) impurity is increased. The dependence of the absorption coefficients on the impurity position is also examined for different polarizations. Our results show that the absorption coefficient has local maximum (minimum) for a given value of impurity position for Y-polarized (X-polarized) light.

  9. A correlation test of the intrinsic interpretation of QSO absorption redshifts

    NASA Technical Reports Server (NTRS)

    Opher, R.

    1975-01-01

    It is noted that the general intrinsic interpretation of QSO absorption redshifts predicts a high probability of clustering for the expulsion velocities of clouds ejected from a QSO core and that a correlation function has been defined which depends on the probability of clustering of three or more expulsion velocities. A test of this correlation is formulated which utilizes data on pairs of QSOs with similar emission redshifts and at least three well established absorption redshifts with corresponding expulsion velocities greater than 0.02c. It is shown that the correlation should be positive (maximum value +100%) if the absorption systems are intrinsic and correlated, zero if there is no physical connection among these systems, and negative if a strong anticorrelation exists or QSOs tend to eject one or two clouds at well separated characteristic velocities. Data on five QSOs are analyzed, and large positive values are obtained for the correlations.

  10. Chaotic systems with absorption.

    PubMed

    Altmann, Eduardo G; Portela, Jefferson S E; Tél, Tamás

    2013-10-01

    Motivated by applications in optics and acoustics we develop a dynamical-system approach to describe absorption in chaotic systems. We introduce an operator formalism from which we obtain (i) a general formula for the escape rate κ in terms of the natural conditionally invariant measure of the system, (ii) an increased multifractality when compared to the spectrum of dimensions D(q) obtained without taking absorption and return times into account, and (iii) a generalization of the Kantz-Grassberger formula that expresses D(1) in terms of κ, the positive Lyapunov exponent, the average return time, and a new quantity, the reflection rate. Simulations in the cardioid billiard confirm these results. PMID:24138240

  11. Inversion of instantaneous equivalent absorption coefficient and its application

    SciTech Connect

    Weihua, W. )

    1992-01-01

    Absorption coefficient is an important parameter for reservoir description. The major troubles in extracting absorption coefficient from seismic data are amplitude and waveform distortions; they greatly restrict the inversion which is based on reflection amplitude variation or reflection frequency variation. This paper presents a new method which avoids amplitude and uses waveform variation gradient in wave propagation to make the inversion of absorption coefficient. Apparent absorption coefficient and pseudo absorption coefficient are adopted so as to remove the influence which the waveform distortion due to thin bed tuning brings to absorption coefficient extraction. The final instantaneous equivalent absorption coefficient, a true absorption coefficient which reflects real absorptive character of a seismic medium, can be obtained by subtracting the pseudo absorption coefficient (inversely calculated using maximum entropy) from the apparent absorption coefficient the authors have calculated.

  12. Minimizing the probable maximum flood

    SciTech Connect

    Woodbury, M.S.; Pansic, N. ); Eberlein, D.T. )

    1994-06-01

    This article examines Wisconsin Electric Power Company's efforts to determine an economical way to comply with Federal Energy Regulatory Commission requirements at two hydroelectric developments on the Michigamme River. Their efforts included refinement of the area's probable maximum flood model based, in part, on a newly developed probable maximum precipitation estimate.

  13. Differential optoacoustic absorption detector

    NASA Technical Reports Server (NTRS)

    Shumate, M. S. (Inventor)

    1978-01-01

    A differential optoacoustic absorption detector employed two tapered cells in tandem or in parallel. When operated in tandem, two mirrors were used at one end remote from the source of the beam of light directed into one cell back through the other, and a lens to focus the light beam into the one cell at a principal focus half way between the reflecting mirror. Each cell was tapered to conform to the shape of the beam so that the volume of one was the same as for the other, and the volume of each received maximum illumination. The axes of the cells were placed as close to each other as possible in order to connect a differential pressure detector to the cells with connecting passages of minimum length. An alternative arrangement employed a beam splitter and two lenses to operate the cells in parallel.

  14. Infrared absorption modeling of VOx microbolometer

    NASA Astrophysics Data System (ADS)

    Aggoun, Mehdi; Jiang, Jianliang; Khan, M. K.

    2015-08-01

    The absorption model plays an important role in the design of the microbolometer structure regarding the determination of the optimum thickness of the structure layers. Moreover, the infrared absorption depends on the wavelength of the radiation and the material properties. In this paper, we presented an Infrared absorption model with absorption coefficient of 96% at maximum absorption wavelength of 9.89μm which is very close to the expected value 10μm. This model was established by using MATLAB so that the simulation of the infrared absorption of the VOx microbolometer could be accomplished. In order to confirm the role of this modeling in the design of the device structure, comparison with other structures is also studied in this paper.

  15. Arctic Sea Ice Maximum 2011

    NASA Video Gallery

    AMSR-E Arctic Sea Ice: September 2010 to March 2011: Scientists tracking the annual maximum extent of Arctic sea ice said that 2011 was among the lowest ice extents measured since satellites began ...

  16. Measurement of the depolarization ratio of Rayleigh scattering at absorption bands

    NASA Astrophysics Data System (ADS)

    Anglister, J.; Steinberg, I. Z.

    1981-01-01

    Measurements of the depolarization ratio ρv of light scattered by the pigments lycopene and β-carotene at the red part of their absorption bands yielded values which are very close to the theoretical value 1/3 of a fully anisotropic molecular polarizability, i.e., that due to an electric dipole moment. Measurements of ρv at the blue edge of the visible absorption band of pinacyanol chloride yielded a value of 0.75 at 472.2 nm, which is the maximum value that a depolarization ratio can assume, and is attained if the average molecular polarizability is zero. This is possible only if the diagonalized polarizability tensor has at least one negative element to counterbalance the positive ones. A negative refractive index at the blue edge of the absorption band is thus experimentally demonstrated.

  17. Convex accelerated maximum entropy reconstruction

    NASA Astrophysics Data System (ADS)

    Worley, Bradley

    2016-04-01

    Maximum entropy (MaxEnt) spectral reconstruction methods provide a powerful framework for spectral estimation of nonuniformly sampled datasets. Many methods exist within this framework, usually defined based on the magnitude of a Lagrange multiplier in the MaxEnt objective function. An algorithm is presented here that utilizes accelerated first-order convex optimization techniques to rapidly and reliably reconstruct nonuniformly sampled NMR datasets using the principle of maximum entropy. This algorithm - called CAMERA for Convex Accelerated Maximum Entropy Reconstruction Algorithm - is a new approach to spectral reconstruction that exhibits fast, tunable convergence in both constant-aim and constant-lambda modes. A high-performance, open source NMR data processing tool is described that implements CAMERA, and brief comparisons to existing reconstruction methods are made on several example spectra.

  18. The Maximum Density of Water.

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    1985-01-01

    Discusses a series of experiments performed by Thomas Hope in 1805 which show the temperature at which water has its maximum density. Early data cast into a modern form as well as guidelines and recent data collected from the author provide background for duplicating Hope's experiments in the classroom. (JN)

  19. Maximum cooling and maximum efficiency of thermoacoustic refrigerators

    NASA Astrophysics Data System (ADS)

    Tartibu, L. K.

    2016-01-01

    This work provides valid experimental evidence on the difference between design for maximum cooling and maximum efficiency for thermoacoustic refrigerators. In addition, the influence of the geometry of the honeycomb ceramic stack on the performance of thermoacoustic refrigerators is presented as it affects the cooling power. Sixteen cordierite honeycomb ceramic stacks with square cross sections having four different lengths of 26, 48, 70 and 100 mm are considered. Measurements are taken at six different locations of the stack hot ends from the pressure antinode, namely 100, 200, 300, 400, 500 and 600 mm respectively. Measurement of temperature difference across the stack ends at steady state for different stack geometries are used to compute the cooling load and the coefficient of performance. The results obtained with atmospheric air showed that there is a distinct optimum depending on the design goal.

  20. The HI absorption "Zoo"

    NASA Astrophysics Data System (ADS)

    Geréb, K.; Maccagni, F. M.; Morganti, R.; Oosterloo, T. A.

    2015-03-01

    We present an analysis of the H I 21 cm absorption in a sample of 101 flux-selected radio AGN (S1.4 GHz> 50 mJy) observed with the Westerbork Synthesis Radio Telescope (WSRT). We detect H I absorption in 32 objects (30% of the sample). In a previous paper, we performed a spectral stacking analysis on the radio sources, while here we characterize the absorption spectra of the individual detections using the recently presented busy function. The H I absorption spectra show a broad variety of widths, shapes, and kinematical properties. The full width half maximum (FWHM) of the busy function fits of the detected H I lines lies in the range 32 km s-1absorption (FW20) lies in the range 63 km s-1 200 km s-1). We study the kinematical and radio source properties of each group, with the goal of identifying different morphological structures of H I. Narrow lines mostly lie at the systemic velocity and are likely produced by regularly rotating H I disks or gas clouds. More H I disks can be present among galaxies with lines of intermediate widths; however, the H I in these sources is more unsettled. We study the asymmetry parameter and blueshift/redshift distribution of the lines as a function of their width. We find a trend for which narrow profiles are also symmetric, while broad lines are the most asymmetric. Among the broadest lines, more lines appear blueshifted than redshifted, similarly to what was found by previous studies. Interestingly, symmetric broad lines are absent from the sample. We argue that if a profile is broad, it is also asymmetric and shifted relative to the systemic velocity because it is tracing unsettled H I gas. In particular, besides three of the broadest (up to FW20 = 825 km s-1

  1. Electronic Absorption Spectra of Neutral Perylene (C20H12), Terrylene (C30H16), and Quaterrylene (C40H20) and their Positive and Negative Ions: Ne Matrix-Isolation Spectroscopy and Time Dependent Density Functional Theory Calculations

    NASA Technical Reports Server (NTRS)

    Halasinski, Thomas M.; Weisman, Jennifer L.; Lee, Timothy J.; Salama, Farid; Head-Gordon, Martin; Kwak, Dochan (Technical Monitor)

    2002-01-01

    We present a full experimental and theoretical study of an interesting series of polycyclic aromatic hydrocarbons, the oligorylenes. The absorption spectra of perylene, terrylene and quaterrylene in neutral, cationic and anionic charge states are obtained by matrix-isolation spectroscopy in Ne. The experimental spectra are dominated by a bright state that red shifts with growing molecular size. Excitation energies and state symmetry assignments are supported by calculations using time dependent density functional theory methods. These calculations also provide new insight into the observed trends in oscillator strength and excitation energy for the bright states: the oscillator strength per unit mass of carbon increases along the series.

  2. Maximum Power Point Regulator System

    NASA Astrophysics Data System (ADS)

    Simola, J.; Savela, K.; Stenberg, J.; Tonicello, F.

    2011-10-01

    The target of the study done under the ESA contract No.17830/04/NL/EC (GSTP4) for Maximum Power Point Regulator System (MPPRS) was to investigate, design and test a modular power system (a core PCU) fulfilling requirement for maximum power transfer even after a single failure in the Power System by utilising a power concept without any potential and credible single point failure. The studied MPPRS concept is of a modular construction, able to track the MPP individually on each SA sections, maintaining its functionality and full power capability after a loss of a complete MPPR module (by utilizingN+1module).Various add-on DCDC converter topology candidates were investigated and redundancy, failure mechanisms and protection aspects were studied

  3. Solar maximum: Solar array degradation

    NASA Technical Reports Server (NTRS)

    Miller, T.

    1985-01-01

    The 5-year in-orbit power degradation of the silicon solar array aboard the Solar Maximum Satellite was evaluated. This was the first spacecraft to use Teflon R FEP as a coverglass adhesive, thus avoiding the necessity of an ultraviolet filter. The peak power tracking mode of the power regulator unit was employed to ensure consistent maximum power comparisons. Telemetry was normalized to account for the effects of illumination intensity, charged particle irradiation dosage, and solar array temperature. Reference conditions of 1.0 solar constant at air mass zero and 301 K (28 C) were used as a basis for normalization. Beginning-of-life array power was 2230 watts. Currently, the array output is 1830 watts. This corresponds to a 16 percent loss in array performance over 5 years. Comparison of Solar Maximum Telemetry and predicted power levels indicate that array output is 2 percent less than predictions based on an annual 1.0 MeV equivalent election fluence of 2.34 x ten to the 13th power square centimeters space environment.

  4. Alternative Multiview Maximum Entropy Discrimination.

    PubMed

    Chao, Guoqing; Sun, Shiliang

    2016-07-01

    Maximum entropy discrimination (MED) is a general framework for discriminative estimation based on maximum entropy and maximum margin principles, and can produce hard-margin support vector machines under some assumptions. Recently, the multiview version of MED multiview MED (MVMED) was proposed. In this paper, we try to explore a more natural MVMED framework by assuming two separate distributions p1( Θ1) over the first-view classifier parameter Θ1 and p2( Θ2) over the second-view classifier parameter Θ2 . We name the new MVMED framework as alternative MVMED (AMVMED), which enforces the posteriors of two view margins to be equal. The proposed AMVMED is more flexible than the existing MVMED, because compared with MVMED, which optimizes one relative entropy, AMVMED assigns one relative entropy term to each of the two views, thus incorporating a tradeoff between the two views. We give the detailed solving procedure, which can be divided into two steps. The first step is solving our optimization problem without considering the equal margin posteriors from two views, and then, in the second step, we consider the equal posteriors. Experimental results on multiple real-world data sets verify the effectiveness of the AMVMED, and comparisons with MVMED are also reported. PMID:26111403

  5. Enhanced squeezing by absorption

    NASA Astrophysics Data System (ADS)

    Grünwald, P.; Vogel, W.

    2016-04-01

    Absorption is usually expected to be detrimental to quantum coherence effects. However, there have been few studies into the situation for complex absorption spectra. We consider the resonance fluorescence of excitons in a semiconductor quantum well. The creation of excitons requires absorption of the incoming pump-laser light. Thus, the absorption spectrum of the medium acts as a spectral filter for the emitted light. Surprisingly, absorption can even improve quantum effects, as is demonstrated for the squeezing of the resonance fluorescence of the quantum-well system. This effect can be explained by an improved phase matching due to absorption.

  6. Triple effect absorption chiller utilizing two refrigeration circuits

    SciTech Connect

    De Vault, R.C.

    1988-03-22

    A heat absorption method for an absorption chiller is described comprising: (a) providing a first absorption system circuit for operation within a first temperature range; (b) providing a second absorption system circuit for operation within a second temperature range which has a lower maximum temperature than the first temperature range; (c) heat exchanging refrigerant and absorber solution from the first circuit condenser and absorber with absorption solution from the generator of the second circuit; and (d) the evaporator of the first circuit and the evaporator of the second circuit both being disposed in thermal communication with an external heat load to withdraw heat from the heat load.

  7. D-xylose absorption

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003606.htm D-xylose absorption To use the sharing features on this page, please enable JavaScript. D-xylose absorption is a laboratory test to determine ...

  8. Multistage quantum absorption heat pumps

    NASA Astrophysics Data System (ADS)

    Correa, Luis A.

    2014-04-01

    It is well known that heat pumps, while being all limited by the same basic thermodynamic laws, may find realization on systems as "small" and "quantum" as a three-level maser. In order to quantitatively assess how the performance of these devices scales with their size, we design generalized N-dimensional ideal heat pumps by merging N -2 elementary three-level stages. We set them to operate in the absorption chiller mode between given hot and cold baths and study their maximum achievable cooling power and the corresponding efficiency as a function of N. While the efficiency at maximum power is roughly size-independent, the power itself slightly increases with the dimension, quickly saturating to a constant. Thus, interestingly, scaling up autonomous quantum heat pumps does not render a significant enhancement beyond the optimal double-stage configuration.

  9. Multistage quantum absorption heat pumps.

    PubMed

    Correa, Luis A

    2014-04-01

    It is well known that heat pumps, while being all limited by the same basic thermodynamic laws, may find realization on systems as "small" and "quantum" as a three-level maser. In order to quantitatively assess how the performance of these devices scales with their size, we design generalized N-dimensional ideal heat pumps by merging N-2 elementary three-level stages. We set them to operate in the absorption chiller mode between given hot and cold baths and study their maximum achievable cooling power and the corresponding efficiency as a function of N. While the efficiency at maximum power is roughly size-independent, the power itself slightly increases with the dimension, quickly saturating to a constant. Thus, interestingly, scaling up autonomous quantum heat pumps does not render a significant enhancement beyond the optimal double-stage configuration. PMID:24827213

  10. Triple effect absorption chiller utilizing two refrigeration circuits

    SciTech Connect

    DeVault, R.C.

    1988-03-22

    This patent describes a heat absorption method for an absorption chiller. It comprises: providing a firs absorption system circuit for operation within a first temperature range, providing a second absorption system circuit for operation within a second temperature range; heat exchanging refrigerant and absorber solution; thermal communication with an external heat load. This patent describes a heat absorption apparatus for use as an absorption chiller. It includes: a first absorption system circuit for operation within a first temperature range; a second absorption system circuit for operation within a second temperature range which has a lower maximum temperature relative to the first temperature range; the first circuit having generator means, condenser means, evaporator means, and absorber means operatively connected together; the second circuit having generator means condenser means, evaporator means, and absorber means operative connected together; and the first circuit condenser means and the first circuit absorber means being in heat exchange communication with the second circuit generator means.

  11. Economics and Maximum Entropy Production

    NASA Astrophysics Data System (ADS)

    Lorenz, R. D.

    2003-04-01

    Price differentials, sales volume and profit can be seen as analogues of temperature difference, heat flow and work or entropy production in the climate system. One aspect in which economic systems exhibit more clarity than the climate is that the empirical and/or statistical mechanical tendency for systems to seek a maximum in production is very evident in economics, in that the profit motive is very clear. Noting the common link between 1/f noise, power laws and Self-Organized Criticality with Maximum Entropy Production, the power law fluctuations in security and commodity prices is not inconsistent with the analogy. There is an additional thermodynamic analogy, in that scarcity is valued. A commodity concentrated among a few traders is valued highly by the many who do not have it. The market therefore encourages via prices the spreading of those goods among a wider group, just as heat tends to diffuse, increasing entropy. I explore some empirical price-volume relationships of metals and meteorites in this context.

  12. KrF- and ArF-excimer-laser-induced absorption in silica glasses produced by melting synthetic silica powder

    SciTech Connect

    Kuzuu, Nobu; Sasaki, Toshiya; Kojima, Tatsuya; Tanaka, Jun-ichiro; Nakamura, Takayuki; Horikoshi, Hideharu

    2013-07-07

    KrF- and ArF-excimer-laser-induced absorption of silica glasses produced by electric melting and flame fusion of synthetic silica powder were investigated. The growth of KrF-laser-induced absorption was more gradual than that of ArF-laser-induced absorption. Induced absorption spectra exhibited a peak at about 5.8 eV, of which the position and width differed slightly among samples and laser species. Widths of ArF-laser-induced absorption spectra were wider than those of KrF-laser-induced spectra. KrF-laser-induced absorption is reproducible by two Gaussian absorption bands peaking at 5.80 eV with full width at half maximum (FWHM) of 0.62 eV and at 6.50 eV with FWHM of 0.74 eV. For reproduction of ArF-laser-induced absorption, Gaussian bands at 5.41 eV with FWHM of 0.62 eV was necessary in addition to components used for reproducing KrF-laser-induced absorption. Based on the discussion of the change of defect structures evaluated from change of absorption components, we proposed that the precursor of the 5.8-eV band ascribed to E Prime center ({identical_to}Si{center_dot}) is {identical_to}Si-H HO-Si{identical_to} structures formed by the reaction between strained Si-O-Si bonds and interstitial H{sub 2} molecules during the irradiation.

  13. Discrimination networks for maximum selection.

    PubMed

    Jain, Brijnesh J; Wysotzki, Fritz

    2004-01-01

    We construct a novel discrimination network using differentiating units for maximum selection. In contrast to traditional competitive architectures like MAXNET the discrimination network does not only signal the winning unit, but also provides information about its evidence. In particular, we show that a discrimination network converges to a stable state within finite time and derive three characteristics: intensity normalization (P1), contrast enhancement (P2), and evidential response (P3). In order to improve the accuracy of the evidential response we incorporate distributed redundancy into the network. This leads to a system which is not only robust against failure of single units and noisy data, but also enables us to sharpen the focus on the problem given in terms of a more accurate evidential response. The proposed discrimination network can be regarded as a connectionist model for competitive learning by evidence. PMID:14690714

  14. Percutaneous absorption of Octopirox.

    PubMed

    Black, J G; Kamat, V B

    1988-01-01

    [14C]Octopirox administered to rats by intubation or injection was excreted mostly in the faeces (65-85% of the dose) with smaller amounts (6-19%) in the urine. Blood levels after intubation of Octopirox (4.8 mg/kg body weight) reached a maximum equivalent to 0.137 micrograms/ml at 2 hr and declined to 0.007 micrograms/ml at 48 hr after administration. Tissue levels were low, the greatest was the liver with the equivalent of 3 micrograms Octopirox at 6 hr after intubation. With female rats skin penetration of Octopirox at 1% (v/v) in shampoo without rinsing was 65.1 micrograms/cm2 under non-occlusive conditions for 48 hr. When the skin was rinsed after a 10-min contact, penetration was reduced to 3.4 micrograms/cm2 under occlusive, and 2.0 micrograms/cm2 under non-occlusive conditions. Skin penetration of Octopirox was dependent on duration of contact up to 10 min before rinsing. Penetration at 1% Octopirox increased significantly from 2.4 micrograms/cm2 after 2.5 min exposure to 4.5 micrograms/cm2 after 10 min contact, but there was no further increase in penetration with a 20-min application. Skin penetration and deposition of Octopirox were both proportional to Octopirox concentration between 0.1 and 1% (w/v); skin penetration increased from 0.31 to 3.6 micrograms/cm2 while deposition increased from 0.8 to 7.6 micrograms/cm2. There was no significant difference between the penetration through clipped skin and hairy skin from an application of 1% Octopirox for 5 min followed by rinsing. Under non-occlusive conditions, penetration was 1.5 micrograms/cm2 for both types of skin. Blood levels after topical application (15.4 mg/kg body weight) without rinsing and with occlusion reached the equivalent of 0.32 micrograms/ml at 6 hr. However, when the skin was rinsed and protected with a non-occlusive patch blood levels were reduced to a maximum equivalent to 0.02 micrograms/ml at 1 hr after application. The safety factor estimated for the consumer using a shampoo

  15. The maximum drag reduction asymptote

    NASA Astrophysics Data System (ADS)

    Choueiri, George H.; Hof, Bjorn

    2015-11-01

    Addition of long chain polymers is one of the most efficient ways to reduce the drag of turbulent flows. Already very low concentration of polymers can lead to a substantial drag and upon further increase of the concentration the drag reduces until it reaches an empirically found limit, the so called maximum drag reduction (MDR) asymptote, which is independent of the type of polymer used. We here carry out a detailed experimental study of the approach to this asymptote for pipe flow. Particular attention is paid to the recently observed state of elasto-inertial turbulence (EIT) which has been reported to occur in polymer solutions at sufficiently high shear. Our results show that upon the approach to MDR Newtonian turbulence becomes marginalized (hibernation) and eventually completely disappears and is replaced by EIT. In particular, spectra of high Reynolds number MDR flows are compared to flows at high shear rates in small diameter tubes where EIT is found at Re < 100. The research leading to these results has received funding from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme (FP7/2007-2013) under REA grant agreement n° [291734].

  16. Maximum entropy production in daisyworld

    NASA Astrophysics Data System (ADS)

    Maunu, Haley A.; Knuth, Kevin H.

    2012-05-01

    Daisyworld was first introduced in 1983 by Watson and Lovelock as a model that illustrates how life can influence a planet's climate. These models typically involve modeling a planetary surface on which black and white daisies can grow thus influencing the local surface albedo and therefore also the temperature distribution. Since then, variations of daisyworld have been applied to study problems ranging from ecological systems to global climate. Much of the interest in daisyworld models is due to the fact that they enable one to study self-regulating systems. These models are nonlinear, and as such they exhibit sensitive dependence on initial conditions, and depending on the specifics of the model they can also exhibit feedback loops, oscillations, and chaotic behavior. Many daisyworld models are thermodynamic in nature in that they rely on heat flux and temperature gradients. However, what is not well-known is whether, or even why, a daisyworld model might settle into a maximum entropy production (MEP) state. With the aim to better understand these systems, this paper will discuss what is known about the role of MEP in daisyworld models.

  17. Objects of Maximum Electromagnetic Chirality

    NASA Astrophysics Data System (ADS)

    Fernandez-Corbaton, Ivan; Fruhnert, Martin; Rockstuhl, Carsten

    2016-07-01

    We introduce a definition of the electromagnetic chirality of an object and show that it has an upper bound. Reciprocal objects attain the upper bound if and only if they are transparent for all the fields of one polarization handedness (helicity). Additionally, electromagnetic duality symmetry, i.e., helicity preservation upon interaction, turns out to be a necessary condition for reciprocal objects to attain the upper bound. We use these results to provide requirements for the design of such extremal objects. The requirements can be formulated as constraints on the polarizability tensors for dipolar objects or on the material constitutive relations for continuous media. We also outline two applications for objects of maximum electromagnetic chirality: a twofold resonantly enhanced and background-free circular dichroism measurement setup, and angle-independent helicity filtering glasses. Finally, we use the theoretically obtained requirements to guide the design of a specific structure, which we then analyze numerically and discuss its performance with respect to maximal electromagnetic chirality.

  18. 20 CFR 228.14 - Family maximum.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Family maximum. 228.14 Section 228.14... SURVIVOR ANNUITIES The Tier I Annuity Component § 228.14 Family maximum. (a) Family maximum defined. Under... person's earnings record is limited. This limited amount is called the family maximum. The family...

  19. 20 CFR 228.14 - Family maximum.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 1 2013-04-01 2012-04-01 true Family maximum. 228.14 Section 228.14... SURVIVOR ANNUITIES The Tier I Annuity Component § 228.14 Family maximum. (a) Family maximum defined. Under... person's earnings record is limited. This limited amount is called the family maximum. The family...

  20. 20 CFR 228.14 - Family maximum.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 1 2012-04-01 2012-04-01 false Family maximum. 228.14 Section 228.14... SURVIVOR ANNUITIES The Tier I Annuity Component § 228.14 Family maximum. (a) Family maximum defined. Under... person's earnings record is limited. This limited amount is called the family maximum. The family...

  1. 20 CFR 228.14 - Family maximum.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 1 2014-04-01 2012-04-01 true Family maximum. 228.14 Section 228.14... SURVIVOR ANNUITIES The Tier I Annuity Component § 228.14 Family maximum. (a) Family maximum defined. Under... person's earnings record is limited. This limited amount is called the family maximum. The family...

  2. 20 CFR 228.14 - Family maximum.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Family maximum. 228.14 Section 228.14... SURVIVOR ANNUITIES The Tier I Annuity Component § 228.14 Family maximum. (a) Family maximum defined. Under... person's earnings record is limited. This limited amount is called the family maximum. The family...

  3. Maximum Entropy Principle for Transportation

    NASA Astrophysics Data System (ADS)

    Bilich, F.; DaSilva, R.

    2008-11-01

    In this work we deal with modeling of the transportation phenomenon for use in the transportation planning process and policy-impact studies. The model developed is based on the dependence concept, i.e., the notion that the probability of a trip starting at origin i is dependent on the probability of a trip ending at destination j given that the factors (such as travel time, cost, etc.) which affect travel between origin i and destination j assume some specific values. The derivation of the solution of the model employs the maximum entropy principle combining a priori multinomial distribution with a trip utility concept. This model is utilized to forecast trip distributions under a variety of policy changes and scenarios. The dependence coefficients are obtained from a regression equation where the functional form is derived based on conditional probability and perception of factors from experimental psychology. The dependence coefficients encode all the information that was previously encoded in the form of constraints. In addition, the dependence coefficients encode information that cannot be expressed in the form of constraints for practical reasons, namely, computational tractability. The equivalence between the standard formulation (i.e., objective function with constraints) and the dependence formulation (i.e., without constraints) is demonstrated. The parameters of the dependence-based trip-distribution model are estimated, and the model is also validated using commercial air travel data in the U.S. In addition, policy impact analyses (such as allowance of supersonic flights inside the U.S. and user surcharge at noise-impacted airports) on air travel are performed.

  4. Maximum entropy principal for transportation

    SciTech Connect

    Bilich, F.; Da Silva, R.

    2008-11-06

    In this work we deal with modeling of the transportation phenomenon for use in the transportation planning process and policy-impact studies. The model developed is based on the dependence concept, i.e., the notion that the probability of a trip starting at origin i is dependent on the probability of a trip ending at destination j given that the factors (such as travel time, cost, etc.) which affect travel between origin i and destination j assume some specific values. The derivation of the solution of the model employs the maximum entropy principle combining a priori multinomial distribution with a trip utility concept. This model is utilized to forecast trip distributions under a variety of policy changes and scenarios. The dependence coefficients are obtained from a regression equation where the functional form is derived based on conditional probability and perception of factors from experimental psychology. The dependence coefficients encode all the information that was previously encoded in the form of constraints. In addition, the dependence coefficients encode information that cannot be expressed in the form of constraints for practical reasons, namely, computational tractability. The equivalence between the standard formulation (i.e., objective function with constraints) and the dependence formulation (i.e., without constraints) is demonstrated. The parameters of the dependence-based trip-distribution model are estimated, and the model is also validated using commercial air travel data in the U.S. In addition, policy impact analyses (such as allowance of supersonic flights inside the U.S. and user surcharge at noise-impacted airports) on air travel are performed.

  5. Absorption Characteristics of Vertebrate Non-Visual Opsin, Opn3

    PubMed Central

    Sugihara, Tomohiro; Nagata, Takashi; Mason, Benjamin; Koyanagi, Mitsumasa; Terakita, Akihisa

    2016-01-01

    Most animals possess multiple opsins which sense light for visual and non-visual functions. Here, we show spectral characteristics of non-visual opsins, vertebrate Opn3s, which are widely distributed among vertebrates. We successfully expressed zebrafish Opn3 in mammalian cultured cells and measured its absorption spectrum spectroscopically. When incubated with 11-cis retinal, zebrafish Opn3 formed a blue-sensitive photopigment with an absorption maximum around 465 nm. The Opn3 converts to an all-trans retinal-bearing photoproduct with an absorption spectrum similar to the dark state following brief blue-light irradiation. The photoproduct experienced a remarkable blue-shift, with changes in position of the isosbestic point, during further irradiation. We then used a cAMP-dependent luciferase reporter assay to investigate light-dependent cAMP responses in cultured cells expressing zebrafish, pufferfish, anole and chicken Opn3. The wild type opsins did not produce responses, but cells expressing chimera mutants (WT Opn3s in which the third intracellular loops were replaced with the third intracellular loop of a Gs-coupled jellyfish opsin) displayed light-dependent changes in cAMP. The results suggest that Opn3 is capable of activating G protein(s) in a light-dependent manner. Finally, we used this assay to measure the relative wavelength-dependent response of cells expressing Opn3 chimeras to multiple quantally-matched stimuli. The inferred spectral sensitivity curve of zebrafish Opn3 accurately matched the measured absorption spectrum. We were unable to estimate the spectral sensitivity curve of mouse or anole Opn3, but, like zebrafish Opn3, the chicken and pufferfish Opn3-JiL3 chimeras also formed blue-sensitive pigments. These findings suggest that vertebrate Opn3s may form blue-sensitive G protein-coupled pigments. Further, we suggest that the method described here, combining a cAMP-dependent luciferase reporter assay with chimeric opsins possessing the third

  6. Aerosol Absorption and Radiative Forcing

    NASA Technical Reports Server (NTRS)

    Stier, Philip; Seinfeld, J. H.; Kinne, Stefan; Boucher, Olivier

    2007-01-01

    We present a comprehensive examination of aerosol absorption with a focus on evaluating the sensitivity of the global distribution of aerosol absorption to key uncertainties in the process representation. For this purpose we extended the comprehensive aerosol-climate model ECHAM5-HAM by effective medium approximations for the calculation of aerosol effective refractive indices, updated black carbon refractive indices, new cloud radiative properties considering the effect of aerosol inclusions, as well as by modules for the calculation of long-wave aerosol radiative properties and instantaneous aerosol forcing. The evaluation of the simulated aerosol absorption optical depth with the AERONET sun-photometer network shows a good agreement in the large scale global patterns. On a regional basis it becomes evident that the update of the BC refractive indices to Bond and Bergstrom (2006) significantly improves the previous underestimation of the aerosol absorption optical depth. In the global annual-mean, absorption acts to reduce the shortwave anthropogenic aerosol top-of-atmosphere (TOA) radiative forcing clear-sky from -0.79 to -0.53 W m(sup -2) (33%) and all-sky from -0.47 to -0.13W m(sup -2 (72%). Our results confirm that basic assumptions about the BC refractive index play a key role for aerosol absorption and radiative forcing. The effect of the usage of more accurate effective medium approximations is comparably small. We demonstrate that the diversity in the AeroCom land-surface albedo fields contributes to the uncertainty in the simulated anthropogenic aerosol radiative forcings: the usage of an upper versus lower bound of the AeroCom land albedos introduces a global annual-mean TOA forcing range of 0.19W m(sup -2) (36%) clear-sky and of 0.12W m(sup -2) (92%) all-sky. The consideration of black carbon inclusions on cloud radiative properties results in a small global annual-mean all-sky absorption of 0.05W m(sup -2) and a positive TOA forcing perturbation of 0

  7. Solar absorption surface panel

    DOEpatents

    Santala, Teuvo J.

    1978-01-01

    A composite metal of aluminum and nickel is used to form an economical solar absorption surface for a collector plate wherein an intermetallic compound of the aluminum and nickel provides a surface morphology with high absorptance and relatively low infrared emittance along with good durability.

  8. Fluorescent optical position sensor

    DOEpatents

    Weiss, Jonathan D.

    2005-11-15

    A fluorescent optical position sensor and method of operation. A small excitation source side-pumps a localized region of fluorescence at an unknown position along a fluorescent waveguide. As the fluorescent light travels down the waveguide, the intensity of fluorescent light decreases due to absorption. By measuring with one (or two) photodetectors the attenuated intensity of fluorescent light emitted from one (or both) ends of the waveguide, the position of the excitation source relative to the waveguide can be determined by comparing the measured light intensity to a calibrated response curve or mathematical model. Alternatively, excitation light can be pumped into an end of the waveguide, which generates an exponentially-decaying continuous source of fluorescent light along the length of the waveguide. The position of a photodetector oriented to view the side of the waveguide can be uniquely determined by measuring the intensity of the fluorescent light emitted radially at that location.

  9. Percutaneous absorption of drugs.

    PubMed

    Wester, R C; Maibach, H I

    1992-10-01

    The skin is an evolutionary masterpiece of living tissue which is the final control unit for determining the local and systemic availability of any drug which must pass into and through it. In vivo in humans, many factors will affect the absorption of drugs. These include individual biological variation and may be influenced by race. The skin site of the body will also influence percutaneous absorption. Generally, those body parts exposed to the open environment (and to cosmetics, drugs and hazardous toxic substances) are most affected. Treating patients may involve single daily drug treatment or multiple daily administration. Finally, the body will be washed (normal daily process or when there is concern about skin decontamination) and this will influence percutaneous absorption. The vehicle of a drug will affect release of drug to skin. On skin, the interrelationships of this form of administration involve drug concentration, surface area exposed, frequency and time of exposure. These interrelationships determine percutaneous absorption. Accounting for all the drug administered is desirable in controlled studies. The bioavailability of the drug then is assessed in relationship to its efficacy and toxicity in drug development. There are methods, both quantitative and qualitative, in vitro and in vivo, for studying percutaneous absorption of drugs. Animal models are substituted for humans to determine percutaneous absorption. Each of these methods thus becomes a factor in determining percutaneous absorption because they predict absorption in humans. The relevance of these predictions to humans in vivo is of intense research interest. The most relevant determination of percutaneous absorption of a drug in humans is when the drug in its approved formulation is applied in vivo to humans in the intended clinical situation. Deviation from this scenario involves the introduction of variables which may alter percutaneous absorption. PMID:1296607

  10. Graphene intracavity spaser absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Lozovik, Yu. E.; Nechepurenko, I. A.; Dorofeenko, A. V.

    2016-09-01

    We propose an intracavity plasmon absorption spectroscopy method based on graphene active plasmonics. It is shown that the plasmonic cavity contribution to the sensitivity is proportional to the quality factor Q of the graphene plasmonic cavity and reaches two orders of magnitude. The addition of gain medium into the cavity increases the sensitivity of method. Maximum sensitivity is reached in the vicinity of the plasmon generation threshold. The gain contribution to the sensitivity is proportional to Q1/2. The giant amplification of sensitivity in the graphene plasmon generator is associated with a huge path length, limited only by the decoherence processes. An analytical estimation of the sensitivity to loss caused by analyzed particles (molecules, nanoparticles, etc.) normalized by the single pass plasmon scheme is derived. Usage of graphene nanoflakes as plasmonic cavity allows a high spatial resolution to be reached, in addition to high sensitivity.

  11. Nursing Positions

    MedlinePlus

    ... Story" 5 Things to Know About Zika & Pregnancy Nursing Positions KidsHealth > For Parents > Nursing Positions Print A ... and actually needs to feed. Getting Comfortable With Breastfeeding Nursing can be one of the most challenging ...

  12. Quasar Absorption Studies

    NASA Technical Reports Server (NTRS)

    Mushotzky, Richard (Technical Monitor); Elvis, Martin

    2004-01-01

    The aim of the proposal is to investigate the absorption properties of a sample of inter-mediate redshift quasars. The main goals of the project are: Measure the redshift and the column density of the X-ray absorbers; test the correlation between absorption and redshift suggested by ROSAT and ASCA data; constrain the absorber ionization status and metallicity; constrain the absorber dust content and composition through the comparison between the amount of X-ray absorption and optical dust extinction. Unanticipated low energy cut-offs where discovered in ROSAT spectra of quasars and confirmed by ASCA, BeppoSAX and Chandra. In most cases it was not possible to constrain adequately the redshift of the absorber from the X-ray data alone. Two possibilities remain open: a) absorption at the quasar redshift; and b) intervening absorption. The evidences in favour of intrinsic absorption are all indirect. Sensitive XMM observations can discriminate between these different scenarios. If the absorption is at the quasar redshift we can study whether the quasar environment evolves with the Cosmic time.

  13. Maximum Likelihood Estimation in Generalized Rasch Models.

    ERIC Educational Resources Information Center

    de Leeuw, Jan; Verhelst, Norman

    1986-01-01

    Maximum likelihood procedures are presented for a general model to unify the various models and techniques that have been proposed for item analysis. Unconditional maximum likelihood estimation, proposed by Wright and Haberman, and conditional maximum likelihood estimation, proposed by Rasch and Andersen, are shown as important special cases. (JAZ)

  14. 14 CFR 1261.102 - Maximum amount.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Maximum amount. 1261.102 Section 1261.102 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PROCESSING OF MONETARY CLAIMS (GENERAL) Employees' Personal Property Claims § 1261.102 Maximum amount. From October 1, 1982, to October 30, 1988, the maximum amount that may be...

  15. 14 CFR 1261.102 - Maximum amount.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Maximum amount. 1261.102 Section 1261.102 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PROCESSING OF MONETARY CLAIMS (GENERAL) Employees' Personal Property Claims § 1261.102 Maximum amount. From October 1, 1982, to October 30, 1988, the maximum amount that may be...

  16. Positive Psychology

    ERIC Educational Resources Information Center

    Peterson, Christopher

    2009-01-01

    Positive psychology is a deliberate correction to the focus of psychology on problems. Positive psychology does not deny the difficulties that people may experience but does suggest that sole attention to disorder leads to an incomplete view of the human condition. Positive psychologists concern themselves with four major topics: (1) positive…

  17. Positional plagiocephaly

    PubMed Central

    Cummings, Carl

    2011-01-01

    Cranial asymmetry occurring as a result of forces that deform skull shape in the supine position is known as deformational plagiocephaly. The risk of plagiocephaly may be modified by positioning the baby on alternate days with the head to the right or the left side, and by increasing time spent in the prone position during awake periods. When deformational plagiocephaly is already present, physiotherapy (including positioning equivalent to the preventive positioning, and exercises as needed for torticollis and positional preference) has been shown to be superior to counselling about preventive positioning only. Helmet therapy (moulding therapy) to reduce skull asymmetry has some drawbacks: it is expensive, significantly inconvenient due to the long hours of use per day and associated with skin complications. There is evidence that helmet therapy may increase the initial rate of improvement of asymmetry, but there is no evidence that it improves the final outcome for patients with moderate or severe plagiocephaly. PMID:23024590

  18. X-ray absorption spectral studies of copper (II) mixed ligand complexes

    NASA Astrophysics Data System (ADS)

    Soni, B.; Dar, Davood Ah; Shrivastava, B. D.; Prasad, J.; Srivastava, K.

    2014-09-01

    X-ray absorption spectra at the K-edge of copper have been studied in two copper mixed ligand complexes, one having tetramethyethylenediamine (tmen) and the other having tetraethyethylenediamine (teen) as one of the ligands. The spectra have been recorded at BL-8 dispersive extended X-ray absorption fine structure (EXAFS) beamline at the 2.5 GeV INDUS- 2 synchrotron, RRCAT, Indore, India. The data obtained has been processed using the data analysis program Athena. The energy of the K-absorption edge, chemical shift, edge-width and shift of the principal absorption maximum in the complexes have been determined and discussed. The values of these parameters have been found to be approximately the same in both the complexes indicating that the two complexes possess similar chemical environment around the copper metal atom. The chemical shift has been utilized to estimate effective nuclear charge on the absorbing atom. The normalized EXAFS spectra have been Fourier transformed. The position of the first peak in the Fourier transform gives the value of first shell bond length, which is shorter than the actual bond length because of energy dependence of the phase factors in the sine function of the EXAFS equation. This distance is thus the phase- uncorrected bond length. Bond length has also been determined by Levy's, Lytle's and Lytle, Sayers and Stern's (LSS) methods. The results obtained from LSS and the Fourier transformation methods are comparable with each other, since both are phase uncorrected bond lengths.

  19. Compounds affecting cholesterol absorption

    NASA Technical Reports Server (NTRS)

    Hua, Duy H. (Inventor); Koo, Sung I. (Inventor); Noh, Sang K. (Inventor)

    2004-01-01

    A class of novel compounds is described for use in affecting lymphatic absorption of cholesterol. Compounds of particular interest are defined by Formula I: ##STR1## or a pharmaceutically acceptable salt thereof.

  20. Dipeptide absorption in man

    PubMed Central

    Hellier, M. D.; Holdsworth, C. D.; McColl, I.; Perrett, D.

    1972-01-01

    A quantitative perfusion method has been used to study intestinal absorption of two dipeptides—glycyl-glycine and glycyl-l-alanine—in normal subjects. In each case, the constituent amino acids were absorbed faster when presented as dipeptides than as free amino acids, suggesting intact dipeptide transport. During absorption constituent amino acids were measured within the lumen and it is suggested that these represent amino acids which have diffused back to the lumen after absorption as dipeptide. Portal blood analyses during absorption of a third dipeptide, glycyl-l-lysine, have shown that this dipeptide, known to be transported intact from the intestinal lumen, is hydrolysed to its constitutent amino acids before it reaches portal venous blood. PMID:4652039

  1. Targeted maximum likelihood estimation in safety analysis

    PubMed Central

    Lendle, Samuel D.; Fireman, Bruce; van der Laan, Mark J.

    2013-01-01

    Objectives To compare the performance of a targeted maximum likelihood estimator (TMLE) and a collaborative TMLE (CTMLE) to other estimators in a drug safety analysis, including a regression-based estimator, propensity score (PS)–based estimators, and an alternate doubly robust (DR) estimator in a real example and simulations. Study Design and Setting The real data set is a subset of observational data from Kaiser Permanente Northern California formatted for use in active drug safety surveillance. Both the real and simulated data sets include potential confounders, a treatment variable indicating use of one of two antidiabetic treatments and an outcome variable indicating occurrence of an acute myocardial infarction (AMI). Results In the real data example, there is no difference in AMI rates between treatments. In simulations, the double robustness property is demonstrated: DR estimators are consistent if either the initial outcome regression or PS estimator is consistent, whereas other estimators are inconsistent if the initial estimator is not consistent. In simulations with near-positivity violations, CTMLE performs well relative to other estimators by adaptively estimating the PS. Conclusion Each of the DR estimators was consistent, and TMLE and CTMLE had the smallest mean squared error in simulations. PMID:23849159

  2. Laser Transmission Holograms Maximum Permissible Exposure

    NASA Astrophysics Data System (ADS)

    Dawson, Paula; Wilksch, P. A.

    2010-05-01

    The laser illumination of holograms for public display is governed by international standard IEC 60825-3, to which the Australian Standard AS/NZS 2211.3 conforms. These standards do not accommodate vital mitigating factors of hologram replay that impinge on the level of laser power i.e. angle of the replay reference beam, the divergence of the beam, the distance of the viewer from the holographic plate and the diffraction efficiency of the hologram plate itself. Such factors indicate that a more meaningful calculation of the radiation level would be obtained from direct measurement at the position of the viewer of the hologram. The purpose of this paper is to demonstrate the importance of these factors in realistically determining the maximum permissible exposure (MPE) for viewers of large format holograms. Materials and Methods: A comparison is made between measurements based on the power or energy that can pass through a fully open pupil for Class 3B and Class 4 lasers (1. medical copper bromide laser, 2. diode laser, and 3. argon continuous wave laser), and the actual power levels when the measurement is taken from the beholder's point of view. Discussion and conclusion: these results indicate a need to review current standards.

  3. Optical absorption measurement system

    DOEpatents

    Draggoo, Vaughn G.; Morton, Richard G.; Sawicki, Richard H.; Bissinger, Horst D.

    1989-01-01

    The system of the present invention contemplates a non-intrusive method for measuring the temperature rise of optical elements under high laser power optical loading to determine the absorption coefficient. The method comprises irradiating the optical element with a high average power laser beam, viewing the optical element with an infrared camera to determine the temperature across the optical element and calculating the absorption of the optical element from the temperature.

  4. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2004-08-31

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  5. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2003-10-14

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  6. Saturnian trapped radiation and its absorption by satellites and rings: the first results from pioneer 11.

    PubMed

    Simpson, J A; Bastian, T S; Chenette, D L; Lentz, G A; McKibben, R B; Pyle, K R; Tuzzolino, A J

    1980-01-25

    Electrons and protons accelerated and trapped in a Saturnian magnetic field have been found by the University of Chicago experiments on Pioneer 11 within 20 Saturn radii (Rs) of the planet. In the innermost regions, strong absorption effects due to satellites and ring material were observed, and from approximately 4 Rs inwards to the outer edge of the A ring at 2.30 Rs (where the radiation is absorbed), the intensity distributions of protons (>/= 0.5 million electron volts) and electrons (2 to 20 million electron volts) were axially symmetric, consistent with a centered dipole aligned with the planetary rotation axis. The maximum fluxes observed for protons (> 35 million electron volts and for electrons < 3.4 million electron volts) were 3 x 10(4) and 3 x 10(6) per square centimeter per second, respectively. Absorption of radiation by Mimas provides a means of estimating the radial diffusion coefficient for charged particle transport. However, the rapid flux increases observed between absorption features raise new questions concerning the physics of charged particle transport and acceleration. An absorption feature near 2.5 Rs has led to the discovery of a previously unknown satellite with a diameter of approximately 200 kilometers, semimajor axis of 2.51 Rs, and eccentricity of 0.013. Radiation absorption features that suggest a nonuniform distribution of matter around Saturn have also been found from 2.34 to 2.36 Rs, near the position of the F ring discovered by the Pioneer imaging experiment. Beneath the A, B, and C rings we continued to observe a low flux of high-energy electrons. We conclude that the inner Saturn magnetosphere, because of its near-axial symmetry and the many discrete radiation absorption regions, offers a unique opportunity to study the acceleration and transport of charged particles in a planetary magnetic field. PMID:17833550

  7. Fluid absorption solar energy receiver

    NASA Technical Reports Server (NTRS)

    Bair, Edward J.

    1993-01-01

    A conventional solar dynamic system transmits solar energy to the flowing fluid of a thermodynamic cycle through structures which contain the gas and thermal energy storage material. Such a heat transfer mechanism dictates that the structure operate at a higher temperature than the fluid. This investigation reports on a fluid absorption receiver where only a part of the solar energy is transmitted to the structure. The other part is absorbed directly by the fluid. By proportioning these two heat transfer paths the energy to the structure can preheat the fluid, while the energy absorbed directly by the fluid raises the fluid to its final working temperature. The surface temperatures need not exceed the output temperature of the fluid. This makes the output temperature of the gas the maximum temperature in the system. The gas can have local maximum temperatures higher than the output working temperature. However local high temperatures are quickly equilibrated, and since the gas does not emit radiation, local high temperatures do not result in a radiative heat loss. Thermal radiation, thermal conductivity, and heat exchange with the gas all help equilibrate the surface temperature.

  8. Empathic features of absorption and incongruence.

    PubMed

    Wickramasekera, Ian E

    2007-07-01

    A study was undertaken to examine whether empathy could be related to absorption and incongruence (repressive coping). The participants were 71 graduate students who completed measures of empathy, absorption, and incongruence (repressive coping). The results confirmed a previous finding that empathy appears positively related to absorption (r = .42, p < .001). The results also suggest that affective components of empathy are inversely related to repressive coping (r = -.29, p < .05) while cognitive components are positively related to the social desirability aspects of incongruence (r = .31, p < .01). The findings are collectively discussed in terms of the Empathic Involvement Hypothesis of Hypnosis (Wickramasekera II, 2001), the Four-factor theory of Repressive Coping (Eysenck, 1997), Incongruence (Rogers, 1957), and the High Risk Model of Threat Perception (I. E. Wickramasekera I, 1998). PMID:17685245

  9. Leading-edge slat optimization for maximum airfoil lift

    NASA Technical Reports Server (NTRS)

    Olson, L. E.; Mcgowan, P. R.; Guest, C. J.

    1979-01-01

    A numerical procedure for determining the position (horizontal location, vertical location, and deflection) of a leading edge slat that maximizes the lift of multielement airfoils is presented. The structure of the flow field is calculated by iteratively coupling potential flow and boundary layer analysis. This aerodynamic calculation is combined with a constrained function minimization analysis to determine the position of a leading edge slat so that the suction peak on the nose of the main airfoil is minized. The slat position is constrained by the numerical procedure to ensure an attached boundary layer on the upper surface of the slat and to ensure negligible interaction between the slat wake and the boundary layer on the upper surface of the main airfoil. The highest angle attack at which this optimized slat position can maintain attached flow on the main airfoil defines the optimum slat position for maximum lift. The design method is demonstrated for an airfoil equipped with a leading-edge slat and a trailing edge, single-slotted flap. The theoretical results are compared with experimental data, obtained in the Ames 40 by 80 Foot Wind Tunnel, to verify experimentally the predicted slat position for maximum lift. The experimentally optimized slat position is in good agreement with the theoretical prediction, indicating that the theoretical procedure is a feasible design method.

  10. INTERSTELLAR SODIUM AND CALCIUM ABSORPTION TOWARD SN 2011dh IN M51

    SciTech Connect

    Ritchey, Adam M.; Wallerstein, George E-mail: wall@astro.washington.edu

    2012-03-20

    We present high-resolution echelle observations of SN 2011dh, which exploded in the nearby, nearly face-on spiral galaxy M51. Our data, acquired on three nights when the supernova was near maximum brightness, reveal multiple absorption components in Na I D and Ca II H and K, which we identify with gaseous material in the Galactic disk or low halo and in the disk and halo of M51. The M51 components span a velocity range of over 140 km s{sup -1}, extending well beyond the range exhibited by H I 21 cm emission at the position of the supernova. Since none of the prominent Na I or Ca II components appear to coincide with the peak in H I emission, the supernova may lie just in front of the bulk of the H I disk. The Na I/Ca II ratios for the components with the most extreme positive and negative velocities relative to the disk are {approx}1.0, similar to those for more quiescent components, suggesting that the absorption originates in relatively cool gas. Production scenarios involving a galactic fountain and/or tidal interactions between M51 and its companion would be consistent with these results. The overall weakness of Na I D absorption in the direction of SN 2011dh confirms a low foreground and host galaxy extinction for the supernova.

  11. Modified maximum likelihood registration based on information fusion

    NASA Astrophysics Data System (ADS)

    Qi, Yongqing; Jing, Zhongliang; Hu, Shiqiang

    2007-11-01

    The bias estimation of passive sensors is considered based on information fusion in multi-platform multi-sensor tracking system. The unobservable problem of bearing-only tracking in blind spot is analyzed. A modified maximum likelihood method, which uses the redundant information of multi-sensor system to calculate the target position, is investigated to estimate the biases. Monte Carlo simulation results show that the modified method eliminates the effect of unobservable problem in the blind spot and can estimate the biases more rapidly and accurately than maximum likelihood method. It is statistically efficient since the standard deviation of bias estimation errors meets the theoretical lower bounds.

  12. Seven-effect absorption refrigeration

    DOEpatents

    DeVault, Robert C.; Biermann, Wendell J.

    1989-01-01

    A seven-effect absorption refrigeration cycle is disclosed utilizing three absorption circuits. In addition, a heat exchanger is used for heating the generator of the low absorption circuit with heat rejected from the condenser and absorber of the medium absorption circuit. A heat exchanger is also provided for heating the generator of the medium absorption circuit with heat rejected from the condenser and absorber of the high absorption circuit. If desired, another heat exchanger can also be provided for heating the evaporator of the high absorption circuit with rejected heat from either the condenser or absorber of the low absorption circuit.

  13. Seven-effect absorption refrigeration

    DOEpatents

    DeVault, R.C.; Biermann, W.J.

    1989-05-09

    A seven-effect absorption refrigeration cycle is disclosed utilizing three absorption circuits. In addition, a heat exchanger is used for heating the generator of the low absorption circuit with heat rejected from the condenser and absorber of the medium absorption circuit. A heat exchanger is also provided for heating the generator of the medium absorption circuit with heat rejected from the condenser and absorber of the high absorption circuit. If desired, another heat exchanger can also be provided for heating the evaporator of the high absorption circuit with rejected heat from either the condenser or absorber of the low absorption circuit. 1 fig.

  14. Universality, maximum radiation, and absorption in high-energy collisions of black holes with spin.

    PubMed

    Sperhake, Ulrich; Berti, Emanuele; Cardoso, Vitor; Pretorius, Frans

    2013-07-26

    We explore the impact of black hole spins on the dynamics of high-energy black hole collisions. We report results from numerical simulations with γ factors up to 2.49 and dimensionless spin parameter χ=+0.85, +0.6, 0, -0.6, -0.85. We find that the scattering threshold becomes independent of spin at large center-of-mass energies, confirming previous conjectures that structure does not matter in ultrarelativistic collisions. It has further been argued that in this limit all of the kinetic energy of the system may be radiated by fine tuning the impact parameter to threshold. On the contrary, we find that only about 60% of the kinetic energy is radiated for γ=2.49. By monitoring apparent horizons before and after scattering events we show that the "missing energy" is absorbed by the individual black holes in the encounter, and moreover the individual black-hole spins change significantly. We support this conclusion with perturbative calculations. An extrapolation of our results to the limit γ→∞ suggests that about half of the center-of-mass energy of the system can be emitted in gravitational radiation, while the rest must be converted into rest-mass and spin energy. PMID:23931346

  15. Positive Psychotherapy

    ERIC Educational Resources Information Center

    Seligman, Martin E. P.; Rashid, Tayyab; Parks, Acacia C.

    2006-01-01

    Positive psychotherapy (PPT) contrasts with standard interventions for depression by increasing positive emotion, engagement, and meaning rather than directly targeting depressive symptoms. The authors have tested the effects of these interventions in a variety of settings. In informal student and clinical settings, people not uncommonly reported…

  16. Selective microwave absorption of iron-rich carbon nanotube composites.

    PubMed

    Gui, Xuchun; Wang, Kunlin; Cao, Anyuan; Wei, Jinquan; Lv, Ruitao; Kang, Feiyu; Shu, Qinke; Jia, Yi; Wu, Dehai

    2010-03-01

    We report on high selectivity of microwave absorption by controlling the concentration of carbon nanotubes in polymer composites and matching the dielectric loss and magnetic loss through encapsulation of crystalline Fe nanorods inside nanotubes. The reflection loss reached more than 10 dB (> 90% absorption) by loading nanotubes at concentrations of 1 wt% to 10 wt% into the composites, and the frequencies corresponding to the maximum loss can be tailored throughout the range of 2 to 18 GHz by changing the concentration. A maximum absorption capability (75 dB x GHz) was observed at a CNT loading of about 4.5 wt%. The crystalline structure of encapsulated Fe nanorods can be modified to enhance the reflection loss. Control of absorption selectivity by modifying the structure and concentration of nanoscale fillers could facilitate potential higher-frequency applications (e.g., radar absorbing) of nanocomposites. PMID:20355578

  17. Absorption Voltages and Insulation Resistance in Ceramic Capacitors with Cracks

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander

    2016-01-01

    Time dependence of absorption voltages (Vabs) in different types of low-voltage X5R and X7R ceramic capacitors was monitored for a maximum duration of hundred hours after polarization. To evaluate the effect of mechanical defects on Vabs, cracks in the dielectric were introduced either mechanically or by thermal shock. The maximum absorption voltage, time to roll-off, and the rate of voltage decrease are shown to depend on the crack-related leakage currents and insulation resistance in the parts. A simple model that is based on the Dow equivalent circuit for capacitors with absorption has been developed to assess the insulation resistance of capacitors. Standard measurements of the insulation resistance, contrary to the measurements based on Vabs, are not sensitive to the presence of mechanical defects and fail to reveal capacitors with cracks. Index Terms: Ceramic capacitor, insulation resistance, dielectric absorption, cracking.

  18. Duality in a maximum generalized entropy model

    NASA Astrophysics Data System (ADS)

    Eguchi, Shinto; Komori, Osamu; Ohara, Atsumi

    2015-01-01

    This paper discusses a possible generalization for the maximum entropy principle. A class of generalized entropy is introduced by that of generator functions, in which the maximum generalized distribution model is explicitly derived including q-Gaussian distributions, Wigner semicircle distributions and Pareto distributions. We define a totally geodesic subspace in the total space of all probability density functions in a framework of information geometry. The model of maximum generalized entropy distributions is shown to be totally geodesic. The duality of the model and the estimation in the maximum generalized principle is elucidated to give intrinsic understandings from the point of information geometry.

  19. Energy absorption studied to reduce aircraft crash forces

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The NASA/FAA aircraft safety reseach programs for general aviation aircraft are discussed. Energy absorption of aircraft subflooring and redesign of interior flooring are being studied. The testing of energy absorbing configurations is described. The three NASA advanced concepts performed at neary the maximum possible amount of energy absorption, and one of two minimum modifications concepts performed well. Planned full scale tests are described. Airplane seat concepts are being considered.

  20. Narrow band perfect absorber for maximum localized magnetic and electric field enhancement and sensing applications

    PubMed Central

    Yong, Zhengdong; Zhang, Senlin; Gong, Chensheng; He, Sailing

    2016-01-01

    Plasmonics offer an exciting way to mediate the interaction between light and matter, allowing strong field enhancement and confinement, large absorption and scattering at resonance. However, simultaneous realization of ultra-narrow band perfect absorption and electromagnetic field enhancement is challenging due to the intrinsic high optical losses and radiative damping in metals. Here, we propose an all-metal plasmonic absorber with an absorption bandwidth less than 8 nm and polarization insensitive absorptivity exceeding 99%. Unlike traditional Metal-Dielectric-Metal configurations, we demonstrate that the narrowband perfect absorption and field enhancement are ascribed to the vertical gap plasmonic mode in the deep subwavelength scale, which has a high quality factor of 120 and mode volume of about 10−4 × (λres/n)3. Based on the coupled mode theory, we verify that the diluted field enhancement is proportional to the absorption, and thus perfect absorption is critical to maximum field enhancement. In addition, the proposed perfect absorber can be operated as a refractive index sensor with a sensitivity of 885 nm/RIU and figure of merit as high as 110. It provides a new design strategy for narrow band perfect absorption and local field enhancement, and has potential applications in biosensors, filters and nonlinear optics. PMID:27046540

  1. Narrow band perfect absorber for maximum localized magnetic and electric field enhancement and sensing applications.

    PubMed

    Yong, Zhengdong; Zhang, Senlin; Gong, Chensheng; He, Sailing

    2016-01-01

    Plasmonics offer an exciting way to mediate the interaction between light and matter, allowing strong field enhancement and confinement, large absorption and scattering at resonance. However, simultaneous realization of ultra-narrow band perfect absorption and electromagnetic field enhancement is challenging due to the intrinsic high optical losses and radiative damping in metals. Here, we propose an all-metal plasmonic absorber with an absorption bandwidth less than 8 nm and polarization insensitive absorptivity exceeding 99%. Unlike traditional Metal-Dielectric-Metal configurations, we demonstrate that the narrowband perfect absorption and field enhancement are ascribed to the vertical gap plasmonic mode in the deep subwavelength scale, which has a high quality factor of 120 and mode volume of about 10(-4) × (λres/n)(3). Based on the coupled mode theory, we verify that the diluted field enhancement is proportional to the absorption, and thus perfect absorption is critical to maximum field enhancement. In addition, the proposed perfect absorber can be operated as a refractive index sensor with a sensitivity of 885 nm/RIU and figure of merit as high as 110. It provides a new design strategy for narrow band perfect absorption and local field enhancement, and has potential applications in biosensors, filters and nonlinear optics. PMID:27046540

  2. Narrow band perfect absorber for maximum localized magnetic and electric field enhancement and sensing applications

    NASA Astrophysics Data System (ADS)

    Yong, Zhengdong; Zhang, Senlin; Gong, Chensheng; He, Sailing

    2016-04-01

    Plasmonics offer an exciting way to mediate the interaction between light and matter, allowing strong field enhancement and confinement, large absorption and scattering at resonance. However, simultaneous realization of ultra-narrow band perfect absorption and electromagnetic field enhancement is challenging due to the intrinsic high optical losses and radiative damping in metals. Here, we propose an all-metal plasmonic absorber with an absorption bandwidth less than 8 nm and polarization insensitive absorptivity exceeding 99%. Unlike traditional Metal-Dielectric-Metal configurations, we demonstrate that the narrowband perfect absorption and field enhancement are ascribed to the vertical gap plasmonic mode in the deep subwavelength scale, which has a high quality factor of 120 and mode volume of about 10‑4 × (λres/n)3. Based on the coupled mode theory, we verify that the diluted field enhancement is proportional to the absorption, and thus perfect absorption is critical to maximum field enhancement. In addition, the proposed perfect absorber can be operated as a refractive index sensor with a sensitivity of 885 nm/RIU and figure of merit as high as 110. It provides a new design strategy for narrow band perfect absorption and local field enhancement, and has potential applications in biosensors, filters and nonlinear optics.

  3. Percutaneous absorption from soil.

    PubMed

    Andersen, Rosa Marie; Coman, Garrett; Blickenstaff, Nicholas R; Maibach, Howard I

    2014-01-01

    Abstract Some natural sites, as a result of contaminants emitted into the air and subsequently deposited in soil or accidental industrial release, have high levels of organic and non-organic chemicals in soil. In occupational and recreation settings, these could be potential sources of percutaneous exposure to humans. When investigating percutaneous absorption from soil - in vitro or vivo - soil load, particle size, layering, soil "age" time, along with the methods of performing the experiment and analyzing the results must be taken into consideration. Skin absorption from soil is generally reduced compared with uptake from water/acetone. However, the absorption of some compounds, e.g., pentachlorophenol, chlorodane and PCB 1254, are similar. Lipophilic compounds like dichlorodiphenyltrichloroethane, benzo[A]pyrene, and metals have the tendency to form reservoirs in skin. Thus, one should take caution in interpreting results directly from in vitro studies for risk assessment; in vivo validations are often required for the most relevant risk assessment. PMID:25205703

  4. Infra-red absorption lines by molecules in grain mantles

    NASA Astrophysics Data System (ADS)

    Hagen, W.; Allamandola, L. J.; Greenberg, J. M.

    1980-06-01

    The laboratory spectrum of a solid mixture of H2O, CO, CH3OH, and NH3 at a temperature of 10 K reproduces the shape and peak positions of interstellar features. It is shown that the broad absorption features evident in the MIR spectra of some astronomical objects associated with interstellar dust can be explained by absorptions of molecules in grain mantles.

  5. Two-dimensional probe absorption in coupled quantum dots

    NASA Astrophysics Data System (ADS)

    Liu, Ningwu; Zhang, Yan; Kang, Chengxian; Wang, Zhiping; Yu, Benli

    2016-07-01

    We investigate the two-dimensional (2D) probe absorption in coupled quantum dots. It is found that, due to the position-dependent quantum interference effect, the 2D optical absorption spectrum can be easily controlled via adjusting the system parameters. Thus, our scheme may provide some technological applications in solid-state quantum communication.

  6. Nucleosome Positioning

    PubMed Central

    Nishida, Hiromi

    2012-01-01

    Nucleosome positioning is not only related to genomic DNA compaction but also to other biological functions. After the chromatin is digested by micrococcal nuclease, nucleosomal (nucleosome-bound) DNA fragments can be sequenced and mapped on the genomic DNA sequence. Due to the development of modern DNA sequencing technology, genome-wide nucleosome mapping has been performed in a wide range of eukaryotic species. Comparative analyses of the nucleosome positions have revealed that the nucleosome is more frequently formed in exonic than intronic regions, and that most of transcription start and translation (or transcription) end sites are located in nucleosome linker DNA regions, indicating that nucleosome positioning influences transcription initiation, transcription termination, and gene splicing. In addition, nucleosomal DNA contains guanine and cytosine (G + C)-rich sequences and a high level of cytosine methylation. Thus, the nucleosome positioning system has been conserved during eukaryotic evolution.

  7. Positive Proof.

    ERIC Educational Resources Information Center

    Auty, Geoffrey

    1988-01-01

    Presents experiments which show that in electrostatics there are logical reasons for describing charged materials as positive or negative. Indicates that static and current electricity are not separate areas of physics. Diagrams of experiments and circuits are included. (RT)

  8. Design of Miniaturized Double-Negative Material for Specific Absorption Rate Reduction in Human Head

    PubMed Central

    Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

    2014-01-01

    In this study, a double-negative triangular metamaterial (TMM) structure, which exhibits a resounding electric response at microwave frequency, was developed by etching two concentric triangular rings of conducting materials. A finite-difference time-domain method in conjunction with the lossy-Drude model was used in this study. Simulations were performed using the CST Microwave Studio. The specific absorption rate (SAR) reduction technique is discussed, and the effects of the position of attachment, the distance, and the size of the metamaterials on the SAR reduction are explored. The performance of the double-negative TMMs in cellular phones was also measured in the cheek and the tilted positions using the COMOSAR system. The TMMs achieved a 52.28% reduction for the 10 g SAR. These results provide a guideline to determine the triangular design of metamaterials with the maximum SAR reducing effect for a mobile phone. PMID:25350398

  9. 33 CFR 401.29 - Maximum draft.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Maximum draft. 401.29 Section 401.29 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Seaway Navigation § 401.29 Maximum draft. (a) Notwithstanding any provision herein, the...

  10. 20 CFR 229.48 - Family maximum.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... total wages (see 20 CFR 404.203(m)) for the second year before the individual dies or becomes eligible... 20 Employees' Benefits 1 2014-04-01 2012-04-01 true Family maximum. 229.48 Section 229.48... OVERALL MINIMUM GUARANTEE Computation of the Overall Minimum Rate § 229.48 Family maximum. (a)...

  11. 20 CFR 229.48 - Family maximum.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... total wages (see 20 CFR 404.203(m)) for the second year before the individual dies or becomes eligible... 20 Employees' Benefits 1 2012-04-01 2012-04-01 false Family maximum. 229.48 Section 229.48... OVERALL MINIMUM GUARANTEE Computation of the Overall Minimum Rate § 229.48 Family maximum. (a)...

  12. 20 CFR 229.48 - Family maximum.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... total wages (see 20 CFR 404.203(m)) for the second year before the individual dies or becomes eligible... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Family maximum. 229.48 Section 229.48... OVERALL MINIMUM GUARANTEE Computation of the Overall Minimum Rate § 229.48 Family maximum. (a)...

  13. 20 CFR 229.48 - Family maximum.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... total wages (see 20 CFR 404.203(m)) for the second year before the individual dies or becomes eligible... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Family maximum. 229.48 Section 229.48... OVERALL MINIMUM GUARANTEE Computation of the Overall Minimum Rate § 229.48 Family maximum. (a)...

  14. 20 CFR 229.48 - Family maximum.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... total wages (see 20 CFR 404.203(m)) for the second year before the individual dies or becomes eligible... 20 Employees' Benefits 1 2013-04-01 2012-04-01 true Family maximum. 229.48 Section 229.48... OVERALL MINIMUM GUARANTEE Computation of the Overall Minimum Rate § 229.48 Family maximum. (a)...

  15. 7 CFR 1778.11 - Maximum grants.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 12 2012-01-01 2012-01-01 false Maximum grants. 1778.11 Section 1778.11 Agriculture... (CONTINUED) EMERGENCY AND IMMINENT COMMUNITY WATER ASSISTANCE GRANTS § 1778.11 Maximum grants. (a) Grants not... the filing of an application. (b) Grants made for repairs, partial replacement, or...

  16. 13 CFR 130.440 - Maximum grant.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 13 Business Credit and Assistance 1 2013-01-01 2013-01-01 false Maximum grant. 130.440 Section 130... § 130.440 Maximum grant. No recipient shall receive an SBDC grant exceeding the greater of the minimum statutory amount, or its pro rata share of all SBDC grants as determined by the statutory formula set...

  17. 13 CFR 130.440 - Maximum grant.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 13 Business Credit and Assistance 1 2012-01-01 2012-01-01 false Maximum grant. 130.440 Section 130... § 130.440 Maximum grant. No recipient shall receive an SBDC grant exceeding the greater of the minimum statutory amount, or its pro rata share of all SBDC grants as determined by the statutory formula set...

  18. 7 CFR 1778.11 - Maximum grants.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 12 2013-01-01 2013-01-01 false Maximum grants. 1778.11 Section 1778.11 Agriculture... (CONTINUED) EMERGENCY AND IMMINENT COMMUNITY WATER ASSISTANCE GRANTS § 1778.11 Maximum grants. (a) Grants not... the filing of an application. (b) Grants made for repairs, partial replacement, or...

  19. 13 CFR 130.440 - Maximum grant.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Maximum grant. 130.440 Section 130... § 130.440 Maximum grant. No recipient shall receive an SBDC grant exceeding the greater of the minimum statutory amount, or its pro rata share of all SBDC grants as determined by the statutory formula set...

  20. 14 CFR 1261.102 - Maximum amount.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Maximum amount. 1261.102 Section 1261.102 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PROCESSING OF MONETARY CLAIMS (GENERAL) Employees' Personal Property Claims § 1261.102 Maximum amount. From October 1, 1982, to October 30,...

  1. 14 CFR 1261.102 - Maximum amount.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 5 2013-01-01 2013-01-01 false Maximum amount. 1261.102 Section 1261.102 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PROCESSING OF MONETARY CLAIMS (GENERAL) Employees' Personal Property Claims § 1261.102 Maximum amount. From October 1, 1982, to October 30,...

  2. 13 CFR 130.440 - Maximum grant.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 13 Business Credit and Assistance 1 2011-01-01 2011-01-01 false Maximum grant. 130.440 Section 130.440 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS DEVELOPMENT CENTERS § 130.440 Maximum grant. No recipient shall receive an SBDC grant exceeding the greater of the...

  3. 13 CFR 130.440 - Maximum grant.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 13 Business Credit and Assistance 1 2014-01-01 2014-01-01 false Maximum grant. 130.440 Section 130.440 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS DEVELOPMENT CENTERS § 130.440 Maximum grant. No recipient shall receive an SBDC grant exceeding the greater of the...

  4. Multiplasmon Absorption in Graphene

    NASA Astrophysics Data System (ADS)

    Jablan, Marinko; Chang, Darrick E.

    2015-06-01

    We show that graphene possesses a strong nonlinear optical response in the form of multiplasmon absorption, with exciting implications in classical and quantum nonlinear optics. Specifically, we predict that graphene nanoribbons can be used as saturable absorbers with low saturation intensity in the far-infrared and terahertz spectrum. Moreover, we predict that two-plasmon absorption and extreme localization of plasmon fields in graphene nanodisks can lead to a plasmon blockade effect, in which a single quantized plasmon strongly suppresses the possibility of exciting a second plasmon.

  5. Absorption heat pump system

    DOEpatents

    Grossman, Gershon; Perez-Blanco, Horacio

    1984-01-01

    An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

  6. Water-related absorption in fibrous diamonds

    NASA Astrophysics Data System (ADS)

    Zedgenizov, D. A.; Shiryaev, A. A.; Kagi, H.; Navon, O.

    2003-04-01

    Cubic and coated diamonds from several localities (Brasil, Canada, Yakutia) were investigated using spectroscopic techniques. Special emphasis was put on investigation of water-related features of transmission Infra-red and Raman spectra. Presence of molecular water is inferred from broad absorption bands in IR at 3420 and 1640 cm-1. These bands were observed in many of the investigated samples. It is likely that molecular water is present in microinclusions in liquid state, since no clear indications of solid H_2O (ice VI-VII, Kagi et al., 2000) were found. Comparison of absorption by HOH and OH vibrations shows that diamonds can be separated into two principal groups: those containing liquid water (direct proportionality of OH and HOH absorption) and those with stronger absorption by OH group. Fraction of diamonds in every group depends on their provenance. There might be positive correlation between internal pressure in microinclusions (determined using quartz barometer, Navon et al., 1988) and affiliation with diamonds containing liquid water. In many cases absorption by HOH vibration is considerably lower than absorption by hydroxyl (OH) group. This may be explained if OH groups are partially present in mineral and/or melt inclusions. This hypothesis is supported by following fact: in diamonds with strong absorption by silicates and other minerals shape and position of the OH band differs from that in diamonds with low absorption by minerals. Moreover, in Raman spectra of individual inclusions sometimes the broad band at 3100 cm-1 is observed. This band is OH-related. In some samples water distribution is not homogeneous. Central part of the diamond usually contains more water than outer parts, but this is not a general rule for all the samples. Water absorption usually correlated with absorption of other components (carbonates, silicates and others). At that fibrous diamonds with relatively high content of silicates are characterized by molecular water. OH

  7. Magnetic field generated resistivity maximum in graphite

    NASA Technical Reports Server (NTRS)

    Wollam, J. A.; Kreps, L. W.; Rojeski, M.; Vold, T.; Devaty, R.

    1976-01-01

    In zero magnetic field, B, the electrical resistivity, rho(O,T) of highly oriented pyrolytic (polycrystalline) graphite drops smoothly with decreasing T, becoming constant below 4 K. However, in a fixed applied magnetic field B, the resistivity rho(B,T) goes through a maximum as a function of T, with larger maximum for larger B. The temperature of the maximum increases with B, but saturates to a constant value near 25 K (exact T depends on sample) at high B. In single crystal graphite a maximum in rho(B,T) as a function of T is also present, but has the effects of Landau level quantization superimposed. Several possible explanations for the rho(B,T) maximum are proposed, but a complete explanation awaits detailed calculations involving the energy band structure of graphite, and the particular scattering mechanisms involved.

  8. The determination of absorption cross sections and line profiles in vibrational overtone spectra with the use of intracavity absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Bettermann, H.; Kleist, E.; Kok, R.

    1993-03-01

    This contribution presents quantitative absorption data concerning the 7 th CH overtone stretching vibrations of n-hexane and of methylcyclopentane. The transitions are adapted to Lorentzian and Gaussian line shapes. The bank shape analyses yield the spectral positions, absorption cross sections and linewidths of the investigated transitions.

  9. Gas absorption using a nanofluid solvent: kinetic and equilibrium study

    NASA Astrophysics Data System (ADS)

    Azizi, S.; Peyghambarzadeh, S. M.; Saremi, M.; Tahmasebi, H.

    2014-12-01

    An experimental study has been performed to explore gas absorption in a nanofluid solvent. Propane and propylene were separately absorbed in a non-aqueous based nanofluid composed of N-methyl 2-pyrolidone (NMP) + small amount of TiO2 nanoparticle. Absorption was performed at different initial pressures and nanoparticle concentrations. Results showed that the addition of small amount of nanoparticle enhances the rate of absorption. Nanofluid decreased the time needed to achieve equilibrium and increased the maximum amount of gas absorbed.

  10. One-phonon absorption by type IIa diamonds

    NASA Astrophysics Data System (ADS)

    Kiflawi, I.; Welbourn, C. M.; Woods, G. S.

    1993-02-01

    Brown type IIa diamonds have been found to exhibit a very weak one-phonon infrared absorption that begins near the Raman energy at 1332cm -1, and increases, with decreasing wavenumber, to a maximum at 1016cm -1 with a shoulder on the high-wavenumber side at about 1050cm -1. A colourless type IIa specimen showed an even weaker absorption beginning again near 1332cm -1 and increasing to show two maxima near 1100cm -1 and 1000cm -1. These specimen also showed birefringence patterns between crossed polars that are indicative of plastic deformation. It is suggested that the infrared absorptions are caused by dislocations.

  11. Position Sensitive Microcalorimeters

    NASA Technical Reports Server (NTRS)

    Sadleir, J. E.; Hammock, C.; Figueroa-Feliciano, E.; Stahle, C. K.; Bandler, S.; Saab, T.; Lindeman, M.; Porter, F. S.; Chervenak, J.; Brown, G.

    2004-01-01

    A Position Sensitive Transition-Edge Sensor (PoST) is a microcalorimeter device capable of one-dimensional imaging spectroscopy. The device consists of two Transition-Edge Sensors (TESs) connected to the ends of a long X-ray absorbing strip. The energy of a photon hitting the absorber and the position of the absorption event along the strip is measured from the response in the two sensors by analyzing the relative signal sizes, pulse rise times, and the sum of the pulses measured at each sensor, We report on the recent PoST effort at Goddard for applications to large field of view, high-energy- resolution, X-ray astrophysics.

  12. Formaldehyde Absorption toward W51

    SciTech Connect

    Kogut, A.; Smoot, G.F.; Bennett, C.L.; Petuchowski, S.J.

    1988-04-01

    We have measured formaldehyde (H{sub 2}CO) absorption toward the HII region complex W51A (G49.5-0.4) in the 6 cm and 2 cm wavelength rotational transitions with angular resolution of approximately 4 inch. The continuum HII region shows a large, previously undetected shell structure 5.5 pc along the major axis. We observe no H{sub 2}CO emission in regions of low continuum intensity. The absorption, converted to optical depth, shows a higher degree of clumping than previous maps at lower resolution. The good S/N of the maps allows accurate estimation of the complicated line profiles, showing some of the absorbing clouds to be quite patchy. We list the properties of the opacity spectra for a number of positions both in the clumps and in the more diffuse regions of the absorbing clouds, and derive column densities for the 1{sub 11} and 2{sub 12} rotational levels of ortho-formaldehyde.

  13. Two-Phonon Absorption

    ERIC Educational Resources Information Center

    Hamilton, M. W.

    2007-01-01

    A nonlinear aspect of the acousto-optic interaction that is analogous to multi-photon absorption is discussed. An experiment is described in which the second-order acousto-optically scattered intensity is measured and found to scale with the square of the acoustic intensity. This experiment using a commercially available acousto-optic modulator is…

  14. Total absorption Cherenkov spectrometers

    NASA Astrophysics Data System (ADS)

    Malinovski, E. I.

    2015-05-01

    A short review of 50 years of work done with Cherenkov detectors in laboratories at the Lebedev Physical Institute is presented. The report considers some issues concerning the use of Cherenkov total absorption counters based on lead glass and heavy crystals in accelerator experiments.

  15. Cholesterol Absorption and Metabolism.

    PubMed

    Howles, Philip N

    2016-01-01

    Inhibitors of cholesterol absorption have been sought for decades as a means to treat and prevent cardiovascular diseases (CVDs) associated with hypercholesterolemia. Ezetimibe is the one clear success story in this regard, and other compounds with similar efficacy continue to be sought. In the last decade, the laboratory mouse, with all its genetic power, has become the premier experimental model for discovering the mechanisms underlying cholesterol absorption and has become a critical tool for preclinical testing of potential pharmaceutical entities. This chapter briefly reviews the history of cholesterol absorption research and the various gene candidates that have come under consideration as drug targets. The most common and versatile method of measuring cholesterol absorption is described in detail along with important considerations when interpreting results, and an alternative method is also presented. In recent years, reverse cholesterol transport (RCT) has become an area of intense new interest for drug discovery since this process is now considered another key to reducing CVD risk. The ultimate measure of RCT is sterol excretion and a detailed description is given for measuring neutral and acidic fecal sterols and interpreting the results. PMID:27150091

  16. Lipids: Absorption and transport

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to the hydrophobic nature of lipids, dietary fat is handled differently than protein or carbohydrate with respect with digestion and absorption. Dietary fats are broken down throughout the gastrointestinal system. A unique group of enzymes and cofactors allows this process to proceed in an eff...

  17. ZINC ABSORPTION BY INFANTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Zinc is a vital mineral in human nutrition, and rare cases of overt zinc deficiency are well described in term and preterm infants. A variety of methods have been developed to assess zinc absorption, retention, and balance in humans, either using mass (metabolic) balance or stable isotope-based METH...

  18. Automated stereotactic positioning system.

    PubMed

    Goerss, S J; Kelly, P J; Kall, B A

    1987-01-01

    An automated stereotactic machine has been interfaced to a surgical computer to complete a totally interactive surgical system capable of locating tumor volumes. Stepper motors, activated by the host computer, drive a three-dimensional slide to position the patient's head with respect to a fixed arc, locating the surgical target. Linear encoders on each axis create a closed-loop positioning system and a digital display for visual inspection of the slide's position. The 160-mm arc directs all instrumentation to its isocenter, regardless of the two angular settings, providing maximum freedom in selecting a safe trajectory to the target. Phantom test points compatible with computerized tomographic and magnetic resonance imaging were repeatedly scanned to determine the overall system accuracy, which approached 0.6 mm, depending on the spatial resolution of the image. This stereotactic device may be used to perform stereotactic laser craniotomies, biopsies, 192Ir implants for interstitial radiation, third ventriculostomies and functional procedures. PMID:3329830

  19. Estimating the seasonal maximum light use efficiency

    NASA Astrophysics Data System (ADS)

    Muramatsu, Kanako; Furumi, Shinobu; Soyama, Noriko; Daigo, Motomasa

    2014-11-01

    Light use efficiency (LUE) is a key parameter in estimating gross primary production (GPP) based on global Earth-observation satellite data and model calculations. In current LUE-based GPP estimation models, the maximum LUE is treated as a constant for each biome type. However, the maximum LUE varies seasonally. In this study, seasonal maximum LUE values were estimated from the maximum incident LUE versus the incident photosynthetically active radiation (PAR) and the fraction of absorbed PAR. First, an algorithm to estimate maximum incident LUE was developed to estimate GPP capacity using a light response curve. One of the parameters required for the light response curve was estimated from the linear relationship of the chlorophyll index and the GPP capacity at a high PAR level of 2000 (µmolm-2s-1), and was referred to as" the maximum GPP capacity at 2000". The relationship was determined for six plant functional types: needleleaf deciduous trees, broadleaf deciduous trees, needleleaf evergreen trees, broadleaf evergreen trees, C3 grass, and crops. The maximum LUE values estimated in this study displayed seasonal variation, especially those for deciduous broadleaf forest, but also those for evergreen needleleaf forest.

  20. Position indicator

    DOEpatents

    Tanner, David E.

    1981-01-01

    A nuclear reactor system is described in which a position indicator is provided for detecting and indicating the position of a movable element inside a pressure vessel. The movable element may be a valve element or similar device which moves about an axis. Light from a light source is transmitted from a source outside the pressure vessel to a first region inside the pressure vessel in alignment with the axis of the movable element. The light is redirected by a reflector prism to a second region displaced radially from the first region. The reflector prism moves in response to movement of the movable element about its axis such that the second region moves arcuately with respect to the first region. Sensors are arrayed in an arc corresponding to the arc of movement of the second region and signals are transmitted from the sensors to the exterior of the reactor vessel to provide indication of the position of the movable element.

  1. On the Origin of the Wide HI Absorption Line Towards Sgr A *

    NASA Astrophysics Data System (ADS)

    Dwarakanath, K. S.; Goss, W. M.; Zhao, J. H.; Lang, C. C.

    2004-09-01

    We have imaged a region of ~5 extent surrounding Sgr A* in the HI 21 cm-line absorption using the Very Large Array. A Gaussian decomposition of the optical depth spectra at positions within ~2(~5 pcat 8.5 kpc) of Sgr A* detects a wide linw underlying the many narrow absorption lines. The wide line has a mean peak optical depth of 0.32 ± 0.12 centered at a mean velocity of Vlsr = -4 ± 15 km s-1. The mean full width half maximum is 119 ± 42 km s-1. Such a wide line is absent in the spectra at positions beyond ~2 from Sgr A*. The position-velocity diagrams do not reveal any diffuse feature which could be attributed to a large number of HI clouds along the line of sight to Sgr A*. Consequently, the wide line has no implications either to a global population of shocked HI clouds in the Galaxy or to the energetics of the interstellar medium as was earlier thought.

  2. [Positive psychiatry].

    PubMed

    Timmerby, Nina; Austin, Stephen; Bech, Per

    2016-02-01

    Positive psychiatry (PP) is a field within psychiatry with a particular focus on promoting well-being in people who already have or are at high risk of developing mental or physical illness. PP should be considered a supplement to trad-tional psychiatry and a call for therapists in psychiatry to focus on the person as a whole rather than just as a patient. PP is in line with current national and international health policy focus on promoting positive mental health. PMID:26857411

  3. Positive psychotherapy.

    PubMed

    Seligman, Martin E P; Rashid, Tayyab; Parks, Acacia C

    2006-11-01

    Positive psychotherapy (PPT) contrasts with standard interventions for depression by increasing positive emotion, engagement, and meaning rather than directly targeting depressive symptoms. The authors have tested the effects of these interventions in a variety of settings. In informal student and clinical settings, people not uncommonly reported them to be "life-changing." Delivered on the Web, positive psychology exercises relieved depressive symptoms for at least 6 months compared with placebo interventions, the effects of which lasted less than a week. In severe depression, the effects of these Web exercises were particularly striking. This address reports two preliminary studies: In the first, PPT delivered to groups significantly decreased levels of mild-to-moderate depression through 1-year follow-up. In the second, PPT delivered to individuals produced higher remission rates than did treatment as usual and treatment as usual plus medication among outpatients with major depressive disorder. Together, these studies suggest that treatments for depression may usefully be supplemented by exercises that explicitly increase positive emotion, engagement, and meaning. ((c) 2006 APA, all rights reserved). PMID:17115810

  4. The Maximum Entropy Principle for Generalized Entropies

    NASA Astrophysics Data System (ADS)

    Tsukada, Makoto

    2008-03-01

    It is well known that Gibbs states and the Gaussian distribution are characterized by the maximum entropy principle. In this paper we discuss probability distributions which maximize generalized entropies including Rényi's and Tsal-lis's.

  5. Maximum forces and deflections from orthodontic appliances.

    PubMed

    Burstone, C J; Goldberg, A J

    1983-08-01

    The maximum bending moment of an orthodontic wire is an important parameter in the design and use of an orthodontic appliance. It is the wire property that determines how much force an appliance can deliver. A bending test which allows direct measurement of the maximum bending moment was developed. Data produced from this test are independent of wire length and configuration. The maximum bending moment, percent recovery, and maximum springback were determined for round and rectangular cross sections of stainless steel, nickel-titanium, and beta-titanium wires. The data suggest the need for more specifically defining maximum moment and maximum springback. Three maximum bending moments are described: Me, My, and Mult. My and Mult are clinically the most significant. Appliances that are required to have no permanent deformation must operate below My. Appliances that exhibit marked permanent deformation may be used in some applications and, if so, higher bending moments can be produced. In order of magnitude, the maximum bending moment at yield is largest in stainless steel, beta-titanium, and nickel-titanium for a given cross section. Nickel-titanium and beta-titanium have significantly larger springback than stainless steel determined at the moment at yield. Nickel-titanium did not follow the theoretical ratio between ultimate bending moment and the bending moment at yield, exhibiting a very large ratio. The study supports the hypothesis that most orthodontic appliances are activated in a range where both plastic and elastic behavior occurs; therefore, the use of yield strengths for calculation of force magnitude can lead to a significant error in predicting the forces delivered. PMID:6576645

  6. Maximum-Likelihood Detection Of Noncoherent CPM

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Simon, Marvin K.

    1993-01-01

    Simplified detectors proposed for use in maximum-likelihood-sequence detection of symbols in alphabet of size M transmitted by uncoded, full-response continuous phase modulation over radio channel with additive white Gaussian noise. Structures of receivers derived from particular interpretation of maximum-likelihood metrics. Receivers include front ends, structures of which depends only on M, analogous to those in receivers of coherent CPM. Parts of receivers following front ends have structures, complexity of which would depend on N.

  7. In-vivo absorption properties of algal pigments

    NASA Astrophysics Data System (ADS)

    Bidigare, Robert R.; Ondrusek, Michael E.; Morrow, John H.; Kiefer, Dale A.

    1990-09-01

    Estimates of the in vivo specific absorption coefficients (m2 mg'; 400-750 nm, 2 nm intervals) for the major algal pigment groups (chlorophylls, carotenoids and phycobilins) are presented. "Unpackaged" absorption coefficients were initially obtained by measuring the absorption properties of pure pigment standards spectrophotometrically and "shifting" their absorption maxima to match in vivo positions. Two approaches for estimating the phytoplankton absorption coefficient (spectral reconstruction and spectral decomposition) are compared by linear regression analysis, incorporating concurrent measurements of particulate absorption and pigmentation performed in the Sargasso Sea. Results suggest that "pigment package" effects are minimal for natural assemblages of open-oceanic phytoplankton and that accessory pigments do not always co-vary with chlorophyll a over depth and time.

  8. Generalization of the k-moment method using the maximum entropy principle. Application to the NBKM and full spectrum SLMB gas radiation models

    NASA Astrophysics Data System (ADS)

    André, Frédéric; Vaillon, Rodolphe

    2012-08-01

    The k-moment method is generalized by applying the maximum entropy principle to get several estimates of the k-distribution function on any kind of spectral interval as a function of the first two moments of the absorption coefficient. Corresponding formulations of the blackbody weighted band averaged transmission function of a gaseous uniform path are obtained. Different constraints involving the first and second order positive, first order negative and logarithmic moments are introduced together with a physical meaning whenever it is possible. Different sets of these constraints are considered to get maximum entropy estimates of the distributions functions: the Dirac, exponential, Gamma, inverse Gaussian and reciprocal inverse Gaussian k-distribution functions. Analytical formulas are provided for each of these distributions and for their associated transmission function, as a function of the mean and variance of the absorption coefficient. The methodology can be applied considering any spectral interval: narrow, wide, the full spectrum, continuous or not. Thus the resulting associated transmission and cumulative k-distribution functions can be utilized in the frame of a large variety of gas radiation models. Hence the k-moment method using the maximum entropy principle is assessed in the frame of the NBKM and full spectrum SLMB gas radiation models. A series of test cases implying comparisons with reference Line-by-Line results exhibits which maximum entropy k-distributions are likely to give the best estimations of narrow band or total emitted intensities, curves-of-growth of the total emission function and full spectrum cumulative k-distribution functions. In particular, the inverse Gaussian and Gamma k-distributions seem most of the time to perform very well.

  9. 69. INTERIOR VIEW OF THE ABSORPTION TOWER BUILDING, ABSORPTION TOWER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    69. INTERIOR VIEW OF THE ABSORPTION TOWER BUILDING, ABSORPTION TOWER UNDER CONSTRUCTION. (DATE UNKNOWN). - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

  10. Experimental determination of terahertz atmospheric absorption parameters

    NASA Astrophysics Data System (ADS)

    Slocum, David M.; Goyette, Thomas M.; Giles, Robert H.; Nixon, William E.

    2015-05-01

    The terahertz frequency regime is often used as the `chemical fingerprint' region of the electromagnetic spectrum since many molecules exhibit a dense selection of rotational and vibrational transitions. Water is a major component of the atmosphere and since it has a large dipole moment the propagation of terahertz radiation will be dominated by atmospheric effects. This study will present the results of high-­-resolution broadband measurements of the terahertz atmospheric absorption and detail the technique for directly measuring the pressure broadening coefficients, absolute absorption coefficients, line positions, and continuum effects. Differences between these measured parameters and those tabulated in HITRAN will be discussed. Once the water vapor absorption was characterized, the same technique was used to measure the line parameters for methanol, a trace gas of interest within Earth's atmosphere. Methanol has a dense absorption spectrum in the terahertz frequency region and is an important molecule in fields such as environmental monitoring, security, and astrophysics. The data obtained in the present study will be of immediate use for the remote sensing community, as it is uncommon to measure this many independent parameters as well as to measure the absolute absorption of the transitions. Current models rely on tabulated databases of calculated values for the line parameters measured in this study. Differences between the measured data and those in the databases will be highlighted and discussed.

  11. Pathways of iron absorption.

    PubMed

    Conrad, Marcel E; Umbreit, Jay N

    2002-01-01

    Iron is vital for all living organisms but excess iron can be lethal because it facilitates free radical formation. Thus iron absorption is carefully regulated to maintain an equilibrium between absorption and body loss of iron. In countries where meat is a significant part of the diet, most body iron is derived from dietary heme because heme binds few of the dietary chelators that bind inorganic iron. Uptake of heme into enterocytes occurs as a metalloporphyrin in an endosomal process. Intracellular iron is released from heme by heme oxygenase to enter plasma as inorganic iron. Ferric iron is absorbed via a beta(3) integrin and mobilferrin pathway (IMP) which is unshared with other nutritional metals. Ferrous iron uptake is facilitated by a DMT-1 pathway which is shared with manganese. In the iron deficient gut, large quantities of both mobilferrin and DMT-1 are found in goblet cells and intraluminal mucins suggesting that they are secreted with mucin into the intestinal lumen to bind iron to facilitate uptake by the cells. In the cytoplasm, IMP and DMT associate in a large protein complex called paraferritin which serves as a ferrireductase. Paraferritin solublizes iron binding proteins and reduces iron to make iron available for production of iron containing proteins such as heme. Iron uptake by intestinal absorptive cells is regulated by the iron concentration within the cell. Except in hemochromatosis it remains in equilibrium with total body stores via transferrin receptors on the basolateral membrane of absorptive cells. Increased intracellular iron either up-regulates or satiates iron binding proteins on regulatory proteins to alter their location in the intestinal mucosa. PMID:12547224

  12. An Improved Forecasting Method of Sunspot Maximum

    NASA Astrophysics Data System (ADS)

    Yin, Z.; Tian, L.; Han, Y.; Wang, B.; Han, Y.

    2015-12-01

    It has been paid more and more attention for forecasting sunspot maximum of future solar cycle in recent decades, and a variety of forecasting methods have been studied. However, to make an accurate prediction is still very difficult due to the complexities of the characteristics of solar activity. Some authors summerized a variety of methods for the maximum predictions of 22nd, 23rd, 24th solar cycles, the incomplete statistics are 63, 54 and 75 cases respectively, results of the methods, which the difference between forecasting and observed values within the range of ±15%, are 27.0%, 25.9% and 24.3% respectively. Using the 13 points smoothed value of monthly sunspot numbers, we studied correlation between sunspot number rising rate of the first 24 months of the solar cycle and the coming cycle maximum, published forecasting result that the maximum value was 139.2 ± 18.8 for 23rd solar cycle (Han et al., 2000), and the observed value is 120.8, the error is about 15.2%. The present paper describes our improved forecasting methods. First, Vondrak smoothing method is used to deal with the monthly sunspot numbers. It is studied that the relationship between the rise rate of earlier months of sunspot numbers of this smoothed sequence and the coming maximum value in each solar cycles. The results show that the first 22, 23, 24 months rise rate of sunspot numbers are highly related with the coming maximum values, and simulated prediction of maximum for 22~24 cycles show that using the 22-month rise rate of three solar cycles, the maximum forecasting error is about 13.2%, using 23-month rise rate, the maximum error is about 11.2%, while using 24-month rise rate, the maximum error is only about 9.3%. The new method not only improves the forecasting accuracy but also can make the forecasting time in advance at least half a year than the common method using 13 points monthly smoothed value.

  13. A microfluidic chemical/biological sensing system based on membrane dissolution and optical absorption

    NASA Astrophysics Data System (ADS)

    Sridharamurthy, Sudheer S.; Dong, Liang; Jiang, Hongrui

    2007-01-01

    A microfluidic system to sense chemical and biological analytes using membranes dissolvable by the analyte is demonstrated. The scheme to detect the dissolution of the membrane is based on the difference in optical absorption of the membrane and the fluidic sample being assayed. The presence of the analyte in the sample chemically cleaves the membrane and causes the sample to flow into the membrane area. This causes a change in the optical absorption of the path between the light source and detector. A device comprising the microfluidic channels and the membrane is microfabricated using liquid-phase photopolymerization. A light emitting diode (LED) and a detector with an integrated amplifier are positioned and aligned on either side of the device. The state of the membrane is continuously monitored after introducing the sample. The temporal dissolution characteristics of the membrane are extracted in terms of the output voltage of the detector as a function of time. This is used to determine the concentration of the analyte. The absorption spectra of the membrane and fluidic sample are studied to determine the optimal wavelength that provides the maximum difference in absorbance between the membrane and the sample. In this work, the dissolution of a poly(acrylamide) hydrogel membrane in the presence of a reducing agent (dithiothreitol—DTT) is used as a model system. For this system, with 1 M DTT, complete membrane dissolution occurred after 65 min.

  14. Exciton Absorption in Semiconductor Quantum Wells Driven by a Strong Intersubband Pump Field

    NASA Technical Reports Server (NTRS)

    Liu, Ansheng; Ning, Cun-Zheng

    1999-01-01

    Optical interband excitonic absorption of semiconductor quantum wells (QW's) driven by a coherent pump field is investigated based on semiconductor Bloch equations. The pump field has a photon energy close to the intersubband spacing between the first two conduction subbands in the QW's. An external weak optical field probes the interband transition. The excitonic effects and pump-induced population redistribution within the conduction subbands in the QW system are included. When the density of the electron-hole pairs in the QW structure is low, the pump field induces an Autler-Townes splitting of the exciton absorption spectrum. The split size and the peak positions of the absorption doublet depend not only on the pump frequency and intensity but also on the carrier density. As the density of the electron-hole pairs is increased, the split contrast (the ratio between the maximum and minimum values) is decreased because the exciton effect is suppressed at higher densities due to the many-body screening.

  15. Position sensor

    NASA Technical Reports Server (NTRS)

    Auer, Siegfried (Inventor)

    1988-01-01

    A radiant energy angle sensor is provided wherein the sensitive portion thereof comprises a pair of linear array detectors with each detector mounted normal to the other to provide X and Y channels and a pair of slits spaced from the pair of linear arrays with each of the slits positioned normal to its associated linear array. There is also provided electrical circuit means connected to the pair of linear array detectors and to separate X and Y axes outputs.

  16. Relic Neutrino Absorption Spectroscopy

    SciTech Connect

    Eberle, b

    2004-01-28

    Resonant annihilation of extremely high-energy cosmic neutrinos on big-bang relic anti-neutrinos (and vice versa) into Z-bosons leads to sizable absorption dips in the neutrino flux to be observed at Earth. The high-energy edges of these dips are fixed, via the resonance energies, by the neutrino masses alone. Their depths are determined by the cosmic neutrino background density, by the cosmological parameters determining the expansion rate of the universe, and by the large redshift history of the cosmic neutrino sources. We investigate the possibility of determining the existence of the cosmic neutrino background within the next decade from a measurement of these absorption dips in the neutrino flux. As a by-product, we study the prospects to infer the absolute neutrino mass scale. We find that, with the presently planned neutrino detectors (ANITA, Auger, EUSO, OWL, RICE, and SalSA) operating in the relevant energy regime above 10{sup 21} eV, relic neutrino absorption spectroscopy becomes a realistic possibility. It requires, however, the existence of extremely powerful neutrino sources, which should be opaque to nucleons and high-energy photons to evade present constraints. Furthermore, the neutrino mass spectrum must be quasi-degenerate to optimize the dip, which implies m{sub {nu}} 0.1 eV for the lightest neutrino. With a second generation of neutrino detectors, these demanding requirements can be relaxed considerably.

  17. Positive Psychologists on Positive Constructs

    ERIC Educational Resources Information Center

    Lyubomirsky, Sonja

    2012-01-01

    Comments on the original article by McNulty and Fincham (see record 2011-15476-001). In their article, the authors offered compelling evidence that constructs such as forgiveness and optimism can have both beneficial and adverse consequences, depending on the context. Their caution about labeling particular psychological processes as "positive" is…

  18. Living positively as HIV positive.

    PubMed

    Garraty, Sarah J

    2011-01-01

    A nursing student records a brief biography of a Zambian nurse and certified midwife living with HIV/AIDS while shadowing the nurse during an undergraduate cross-cultural course in Macha, Zambia in January 2009. The nurse strives to live positively, educating, encouraging, and empowering others. PMID:21294466

  19. Absorption of impinging water droplet in porous stones.

    PubMed

    Lee, J B; Radu, A I; Vontobel, P; Derome, D; Carmeliet, J

    2016-06-01

    This paper presents an experimental investigation and numerical analysis of the absorption of water droplets impacting porous stones. The absorption process of an impinging droplet is here fully characterized from spreading to evaporation in terms of absorbed mass during droplet depletion and moisture content distribution in a time-resolved manner for three different natural stones. High-speed imaging and neutron radiography are used to quantify moisture absorption in porous stones of varying moisture properties from deposition until depletion. During impact and spreading, the droplet exhibits a dynamic non-wetting behavior. At maximum spreading, the droplet undergoes pinning, resulting into the contact radius remaining constant until droplet depletion. Absorption undergoes two phases: initially, absorption is hindered due a contact resistance attributed to entrapped air; afterwards, a more perfect capillary contact occurs and absorption goes on until depletion, concurrently with evaporation and further redistribution. A finite-element numerical model for isothermal unsaturated moisture transport in porous media captures the phases of mass absorption in good agreement with the experimental data. Droplet spreading and absorption are highly determined by the impact velocity of the droplet, while moisture content redistribution after depletion is much less dependent on impact conditions. PMID:26975034

  20. Absorptivity of nitric oxide in the fundamental vibrational band

    NASA Astrophysics Data System (ADS)

    Holland, R. F.; Vasquez, M. C.; Beattie, W. H.; McDowell, R. S.

    1983-05-01

    From observations of the spectral absorbance of mixtures of nitric oxide in nitrogen at room temperature, an integrated absorptivity for the NO fundamental band of 137.3 + or - 4.6 per(sq cm atm) at 0 C is derived. The indicated uncertainty is the estimated maximum error.

  1. Corrosion Problems in Absorption Chillers

    ERIC Educational Resources Information Center

    Stetson, Bruce

    1978-01-01

    Absorption chillers use a lithium bromide solution as the medium of absorption and water as the refrigerant. Discussed are corrosion and related problems, tests and remedies, and cleaning procedures. (Author/MLF)

  2. Maximum permissible voltage of YBCO coated conductors

    NASA Astrophysics Data System (ADS)

    Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z.; Hong, Z.; Wang, D.; Zhou, H.; Shen, X.; Shen, C.

    2014-06-01

    Superconducting fault current limiter (SFCL) could reduce short circuit currents in electrical power system. One of the most important thing in developing SFCL is to find out the maximum permissible voltage of each limiting element. The maximum permissible voltage is defined as the maximum voltage per unit length at which the YBCO coated conductors (CC) do not suffer from critical current (Ic) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the Ic degradation or burnout happens. YBCO coated conductors test in the experiment are from American superconductor (AMSC) and Shanghai Jiao Tong University (SJTU). Along with the quenching duration increasing, the maximum permissible voltage of CC decreases. When quenching duration is 100 ms, the maximum permissible of SJTU CC, 12 mm AMSC CC and 4 mm AMSC CC are 0.72 V/cm, 0.52 V/cm and 1.2 V/cm respectively. Based on the results of samples, the whole length of CCs used in the design of a SFCL can be determined.

  3. Absorption Voltages and Insulation Resistance in Ceramic Capacitors with Cracks

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander

    2014-01-01

    Time dependence of absorption voltages (V(sub abs)) in different types of low-voltage X5R and X7R ceramic capacitors was monitored for a maximum duration of hundred hours after polarization. To evaluate the effect of mechanical defects on V(sub abs)), cracks in the dielectric were introduced either mechanically or by thermal shock. The maximum absorption voltage, time to roll-off, and the rate of voltage decrease are shown to depend on the crack-related leakage currents and insulation resistance in the parts. A simple model that is based on the Dow equivalent circuit for capacitors with absorption has been developed to assess the insulation resistance of capacitors. Standard measurements of the insulation resistance, contrary to the measurements based on V(sub abs)), are not sensitive to the presence of mechanical defects and fail to reveal capacitors with cracks.

  4. Positioning apparatus

    DOEpatents

    Vogel, Max A.; Alter, Paul

    1986-05-06

    An apparatus for precisely positioning materials test specimens within the optimum neutron flux path emerging from a neutron source located in a housing. The test specimens are retained in a holder mounted on the free end of a support pivotably mounted and suspended from a movable base plate. The support is gravity biased to urge the holder in a direction longitudinally of the flux path against the housing. Means are provided for moving the base plate in two directions to effect movement of the holder in two mutually perpendicular directions normal to the axis of the flux path.

  5. Positioning apparatus

    DOEpatents

    Vogel, Max A.; Alter, Paul

    1986-01-01

    An apparatus for precisely positioning materials test specimens within the optimum neutron flux path emerging from a neutron source located in a housing. The test specimens are retained in a holder mounted on the free end of a support pivotably mounted and suspended from a movable base plate. The support is gravity biased to urge the holder in a direction longitudinally of the flux path against the housing. Means are provided for moving the base plate in two directions to effect movement of the holder in two mutually perpendicular directions normal to the axis of the flux path.

  6. POSITIONING DEVICE

    DOEpatents

    Wall, R.R.; Peterson, D.L.

    1959-09-15

    A positioner is described for a vertical reactor-control rod. The positioner comprises four grooved friction rotatable members that engage the control rod on all sides and shift it longitudinally. The four friction members are drivingly interconnected for conjoint rotation and comprise two pairs of coaxial members. The members of each pair are urged toward one another by hydraulic or pneumatic pressure and thus grip the control rod so as to hold it in any position or adjust it. Release of the by-draulic or pneumatic pressure permits springs between the friction members of each pair to force them apart, whereby the control rod moves quickly by gravity into the reactor.

  7. Positioning apparatus

    DOEpatents

    Vogel, M.A.; Alter, P.

    1983-07-07

    An apparatus is provided for precisely adjusting the position of an article relative to a beam emerging from a neutron source disposed in a housing. The apparatus includes a support pivotably mounted on a movable base plate and freely suspended therefrom. The support is gravity biased toward the housing and carries an article holder movable in a first direction longitudinally of the axis of said beam and normally urged into engagement against said housing. Means are provided for moving the base plate in two directions to effect movement of the suspended holder in two mutually perpendicular directions, respectively, normal to the axis of the beam.

  8. Acoustic Absorption Characteristics of People.

    ERIC Educational Resources Information Center

    Kingsbury, H. F.; Wallace, W. J.

    1968-01-01

    The acoustic absorption characteristics of informally dressed college students in typical classroom seating are shown to differ substantially from data for formally dressed audiences in upholstered seating. Absorption data, expressed as sabins per person or absorption coefficient per square foot, shows that there is considerable variation between…

  9. Surface tension maximum of liquid 3He

    NASA Astrophysics Data System (ADS)

    Matsumoto, Koichi; Hasegawa, Syuichi; Suzuki, Masaru; Okuda, Yuichi

    2000-07-01

    The surface tension of liquid 3He was measured using the capillary-rise method. Suzuki et al. have reported that its temperature dependence was almost quenched below 120 mK. Here we have examined it with higher precision and found that it has a small maximum around 100 mK. The amount of the maximum is about 3×10 -4 as a fraction of the surface tension at 0 K. The density of liquid 3He increases with temperature by about 5×10 -4 in Δ ρ/ ρ between 0 and 100 mK. This density change could be one of the reasons of the surface tension maximum around 100 mK.

  10. The Maximum Mass of Rotating Strange Stars

    NASA Astrophysics Data System (ADS)

    Szkudlarek, M.; Gondek-Rosiń; ska, D.; Villain, L.; Ansorg, M.

    2012-12-01

    Strange quark stars are considered as a possible alternative to neutron stars as compact objects (e.g. Weber 2003). A hot compact star (a proto-neutron star or a strange star) born in a supernova explosion or a remnant of neutron stars binary merger are expected to rotate differentially and be important sources of gravitational waves. We present results of the first relativistic calculations of differentially rotating strange quark stars for broad ranges of degree of differential rotation and maximum densities. Using a highly accurate, relativistic code we show that rotation may cause a significant increase of maximum allowed mass of strange stars, much larger than in the case of neutron stars with the same degree of differential rotation. Depending on the maximum allowed mass a massive neutron star (strange star) can be temporarily stabilized by differential rotation or collapse to a black hole.

  11. Maximum stabilizer dimension for nonproduct states

    SciTech Connect

    Walck, Scott N.; Lyons, David W.

    2007-08-15

    Composite quantum states can be classified by how they behave under local unitary transformations. Each quantum state has a stabilizer subgroup and a corresponding Lie algebra, the structure of which is a local unitary invariant. In this paper, we study the structure of the stabilizer subalgebra for n-qubit pure states, and find its maximum dimension to be n-1 for nonproduct states of three qubits and higher. The n-qubit Greenberger-Horne-Zeilinger state has a stabilizer subalgebra that achieves the maximum possible dimension for pure nonproduct states. The converse, however, is not true: We show examples of pure 4-qubit states that achieve the maximum nonproduct stabilizer dimension, but have stabilizer subalgebra structures different from that of the n-qubit GHZ state.

  12. Maximum predictive power and the superposition principle

    NASA Technical Reports Server (NTRS)

    Summhammer, Johann

    1994-01-01

    In quantum physics the direct observables are probabilities of events. We ask how observed probabilities must be combined to achieve what we call maximum predictive power. According to this concept the accuracy of a prediction must only depend on the number of runs whose data serve as input for the prediction. We transform each probability to an associated variable whose uncertainty interval depends only on the amount of data and strictly decreases with it. We find that for a probability which is a function of two other probabilities maximum predictive power is achieved when linearly summing their associated variables and transforming back to a probability. This recovers the quantum mechanical superposition principle.

  13. Maximum likelihood clustering with dependent feature trees

    NASA Technical Reports Server (NTRS)

    Chittineni, C. B. (Principal Investigator)

    1981-01-01

    The decomposition of mixture density of the data into its normal component densities is considered. The densities are approximated with first order dependent feature trees using criteria of mutual information and distance measures. Expressions are presented for the criteria when the densities are Gaussian. By defining different typs of nodes in a general dependent feature tree, maximum likelihood equations are developed for the estimation of parameters using fixed point iterations. The field structure of the data is also taken into account in developing maximum likelihood equations. Experimental results from the processing of remotely sensed multispectral scanner imagery data are included.

  14. Absorption heat pumps

    NASA Astrophysics Data System (ADS)

    Huhtinen, M.; Heikkilae, M.; Andersson, R.

    1987-03-01

    The aim of the study was to analyze the technical and economic feasibility of absorption heat pumps in Finland. The work was done as a case study: the technical and economic analyses have been carried out for six different cases, where in each the suitable size and type of the heat pump plant and the auxiliary components and connections were specified. The study also detailed the costs concerning the procurement, installation and test runs of the machinery, as well as the savings in energy costs incurred by the introduction of the plant. Conclusions were drawn of the economic viability of the applications studied. The following cases were analyzed: heat recovery from flue gases and productin of district heat in plants using peat, natural gas, and municipal wastes as a fuel. Heat recovery in the pulp and paper industry for the upgrading of pressure of secondary steam and for the heating of white liquor and combustion and drying the air. Heat recovery in a peat-fulled heat and power plant from flue gases that have been used for the drying of peat. According to the study, the absorption heat pump suits best to the production of district heat, when the heat source is the primary energy is steam produced by the boiler. Included in the flue as condensing is the purification of flue gases. Accordingly, benefit is gained on two levels in thick applications. In heat and power plants the use of absorption heat pumps is less economical, due to the fact that the steam used by the pump reduces the production of electricity, which is rated clearly higher than heat.

  15. The maximum intelligible range of the human voice

    NASA Astrophysics Data System (ADS)

    Boren, Braxton

    This dissertation examines the acoustics of the spoken voice at high levels and the maximum number of people that could hear such a voice unamplified in the open air. In particular, it examines an early auditory experiment by Benjamin Franklin which sought to determine the maximum intelligible crowd for the Anglican preacher George Whitefield in the eighteenth century. Using Franklin's description of the experiment and a noise source on Front Street, the geometry and diffraction effects of such a noise source are examined to more precisely pinpoint Franklin's position when Whitefield's voice ceased to be intelligible. Based on historical maps, drawings, and prints, the geometry and material of Market Street is constructed as a computer model which is then used to construct an acoustic cone tracing model. Based on minimal values of the Speech Transmission Index (STI) at Franklin's position, Whitefield's on-axis Sound Pressure Level (SPL) at 1 m is determined, leading to estimates centering around 90 dBA. Recordings are carried out on trained actors and singers to determine their maximum time-averaged SPL at 1 m. This suggests that the greatest average SPL achievable by the human voice is 90-91 dBA, similar to the median estimates for Whitefield's voice. The sites of Whitefield's largest crowds are acoustically modeled based on historical evidence and maps. Based on Whitefield's SPL, the minimal STI value, and the crowd's background noise, this allows a prediction of the minimally intelligible area for each site. These yield maximum crowd estimates of 50,000 under ideal conditions, while crowds of 20,000 to 30,000 seem more reasonable when the crowd was reasonably quiet and Whitefield's voice was near 90 dBA.

  16. Scattering with absorptive interaction

    NASA Astrophysics Data System (ADS)

    Cassing, W.; Stingl, M.; Weiguny, A.

    1982-07-01

    The S matrix for a wide class of complex and nonlocal potentials is studied, with special attention given to the motion of singularities in the complex k plane as a function of the imaginary coupling strength. Modifications of Levinson's theorem are obtained and discussed. Analytic approximations to the S matrix in the vicinity of narrow resonances are exhibited and compared to numerical results of resonating-group calculations. The problem of defining resonances in the case of complex interactions is discussed, making contact with the usual analysis of scattering in terms of Argand diagrams. NUCLEAR REACTIONS Scattering theory, S matrix for absorptive potentials.

  17. Ultraviolet absorption hygrometer

    DOEpatents

    Gersh, M.E.; Bien, F.; Bernstein, L.S.

    1986-12-09

    An ultraviolet absorption hygrometer is provided including a source of pulsed ultraviolet radiation for providing radiation in a first wavelength region where water absorbs significantly and in a second proximate wavelength region where water absorbs weakly. Ultraviolet radiation in the first and second regions which has been transmitted through a sample path of atmosphere is detected. The intensity of the radiation transmitted in each of the first and second regions is compared and from this comparison the amount of water in the sample path is determined. 5 figs.

  18. Ultraviolet absorption hygrometer

    DOEpatents

    Gersh, Michael E.; Bien, Fritz; Bernstein, Lawrence S.

    1986-01-01

    An ultraviolet absorption hygrometer is provided including a source of pulsed ultraviolet radiation for providing radiation in a first wavelength region where water absorbs significantly and in a second proximate wavelength region where water absorbs weakly. Ultraviolet radiation in the first and second regions which has been transmitted through a sample path of atmosphere is detected. The intensity of the radiation transmitted in each of the first and second regions is compared and from this comparison the amount of water in the sample path is determined.

  19. Light absorption by organic carbon from wood combustion

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Bond, T. C.

    2010-02-01

    Carbonaceous aerosols affect the radiative balance of the Earth by absorbing and scattering light. While black carbon (BC) is highly absorbing, some organic carbon (OC) also has significant absorption, especially at near-ultraviolet and blue wavelengths. To the extent that OC absorbs visible light, it may be a non-negligible contributor to positive direct aerosol radiative forcing. Quantification of that absorption is necessary so that radiative-transfer models can evaluate the net radiative effect of OC. In this work, we examine absorption by primary OC emitted from solid fuel pyrolysis. We provide absorption spectra of this material, which can be related to the imaginary refractive index. This material has polar character but is not fully water-soluble: more than 92% was extractable by methanol or acetone, compared with 73% for water and 52% for hexane. Water-soluble OC contributes to light absorption at both ultraviolet and visible wavelengths. However, a larger portion of the absorption comes from OC that is extractable only by methanol. Absorption spectra of water-soluble OC are similar to literature reports. We compare spectra for material generated with different wood type, wood size and pyrolysis temperature. Higher wood temperature is the main factor creating OC with higher absorption; changing wood temperature from a devolatilizing state of 210 °C to a near-flaming state of 360 °C causes about a factor of four increase in mass-normalized absorption at visible wavelengths. A clear-sky radiative transfer model suggests that, despite the absorption, both high-temperature and low-temperature OC result in negative top-of-atmosphere radiative forcing over a surface with an albedo of 0.19 and positive radiative forcing over bright surfaces. Unless absorption by real ambient aerosol is higher than that measured here, it probably affects global average clear-sky forcing very little, but could be important in energy balances over bright surfaces.

  20. Aerosol optical absorption measurements with photoacoustic spectroscopy

    NASA Astrophysics Data System (ADS)

    Liu, Kun; Wang, Lei; Liu, Qiang; Wang, Guishi; Tan, Tu; Zhang, Weijun; Chen, Weidong; Gao, Xiaoming

    2015-04-01

    Many parameters related to radiative forcing in climate research are known only with large uncertainties. And one of the largest uncertainties in global radiative forcing is the contribution from aerosols. Aerosols can scatter or absorb the electromagnetic radiation, thus may have negative or positive effects on the radiative forcing of the atmosphere, respectively [1]. And the magnitude of the effect is directly related to the quantity of light absorbed by aerosols [2,3]. Thus, sensitivity and precision measurement of aerosol optical absorption is crucial for climate research. Photoacoustic spectroscopy (PAS) is commonly recognized as one of the best candidates to measure the light absorption of aerosols [4]. A PAS based sensor for aerosol optical absorption measurement was developed. A 532 nm semiconductor laser with an effective power of 160 mW was used as a light source of the PAS sensor. The PAS sensor was calibrated by using known concentration NO2. The minimum detectable optical absorption coefficient (OAC) of aerosol was determined to be 1 Mm-1. 24 hours continues measurement of OAC of aerosol in the ambient air was carried out. And a novel three wavelength PAS aerosol OAC sensor is in development for analysis of aerosol wavelength-dependent absorption Angstrom coefficient. Reference [1] U. Lohmann and J. Feichter, Global indirect aerosol effects: a review, Atmos. Chem. Phys. 5, 715-737 (2005) [2] M. Z. Jacobson, Strong radiative heating due to the mixing state of black carbon in atmospheric aerosols, Nature 409, 695-697 (2001) [3] V. Ramanathan and G. Carmichae, Global and regional climate changes due to black carbon, nature geoscience 1, 221-227 (2008) [4] W.P Arnott, H. Moosmuller, C. F. Rogers, T. Jin, and R. Bruch, Photoacoustic spectrometer for measuring light absorption by aerosol: instrument description. Atmos. Environ. 33, 2845-2852 (1999).

  1. The absorption spectra of the complexes of uranium (VI) with some β-diketones

    USGS Publications Warehouse

    Feinstein, H.I.

    1956-01-01

    The absorption spectra of the complexes of uranium (VI) with four β-dike tones were determined under various conditions of pH, concentration of uranium, and alcohol concentration. Under optimum conditions, the maximum molar absorptivity (31,200) is obtained using 2-furoyltrifluoroacetone. This compares with about 4,000 and 19,000 for the thiocyanate and dibenzoylmethane complexes, respectively.

  2. Maximum rotation frequency of strange stars

    SciTech Connect

    Zdunik, J.L.; Haensel, P. )

    1990-07-15

    Using the MIT bag model of strange-quark matter, we calculate the maximum angular frequency of the uniform rotation of strange stars. After studying a broad range of the MIT bag-model parameters, we obtain an upper bound of 12.3 kHz.

  3. 33 CFR 401.29 - Maximum draft.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Maximum draft. 401.29 Section 401.29 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF... 1 The main channels between the Port of Montreal and Lake Erie have a controlling depth of 8.23m....

  4. 33 CFR 401.29 - Maximum draft.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Maximum draft. 401.29 Section 401.29 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF... 1 The main channels between the Port of Montreal and Lake Erie have a controlling depth of 8.23m....

  5. 33 CFR 401.29 - Maximum draft.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Maximum draft. 401.29 Section 401.29 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF... 1 The main channels between the Port of Montreal and Lake Erie have a controlling depth of 8.23m....

  6. 33 CFR 401.29 - Maximum draft.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Maximum draft. 401.29 Section 401.29 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF... tendency to list or squat, so as to avoid striking bottom.1 1 The main channels between the Port...

  7. 5 CFR 9701.312 - Maximum rates.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 3 2012-01-01 2012-01-01 false Maximum rates. 9701.312 Section 9701.312 Administrative Personnel DEPARTMENT OF HOMELAND SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM (DEPARTMENT OF HOMELAND SECURITY-OFFICE OF PERSONNEL MANAGEMENT) DEPARTMENT OF HOMELAND SECURITY HUMAN...

  8. 7 CFR 1778.11 - Maximum grants.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... quantity of potable water, or an anticipated acute shortage or significant decline, cannot exceed $150,000... (CONTINUED) EMERGENCY AND IMMINENT COMMUNITY WATER ASSISTANCE GRANTS § 1778.11 Maximum grants. (a) Grants not to exceed $500,000 may be made to alleviate a significant decline in quantity or quality of...

  9. 7 CFR 1778.11 - Maximum grants.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... quantity of potable water, or an anticipated acute shortage or significant decline, cannot exceed $150,000... (CONTINUED) EMERGENCY AND IMMINENT COMMUNITY WATER ASSISTANCE GRANTS § 1778.11 Maximum grants. (a) Grants not to exceed $500,000 may be made to alleviate a significant decline in quantity or quality of...

  10. 7 CFR 1778.11 - Maximum grants.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... quantity of potable water, or an anticipated acute shortage or significant decline, cannot exceed $150,000... (CONTINUED) EMERGENCY AND IMMINENT COMMUNITY WATER ASSISTANCE GRANTS § 1778.11 Maximum grants. (a) Grants not to exceed $500,000 may be made to alleviate a significant decline in quantity or quality of...

  11. 5 CFR 9701.312 - Maximum rates.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Administrative Personnel DEPARTMENT OF HOMELAND SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM (DEPARTMENT OF HOMELAND SECURITY-OFFICE OF PERSONNEL MANAGEMENT) DEPARTMENT OF HOMELAND SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM Pay and Pay Administration Overview of Pay System § 9701.312 Maximum rates. (a) DHS may...

  12. 5 CFR 9701.312 - Maximum rates.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Administrative Personnel DEPARTMENT OF HOMELAND SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM (DEPARTMENT OF HOMELAND SECURITY-OFFICE OF PERSONNEL MANAGEMENT) DEPARTMENT OF HOMELAND SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM Pay and Pay Administration Overview of Pay System § 9701.312 Maximum rates. (a) DHS may...

  13. 5 CFR 9701.312 - Maximum rates.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Administrative Personnel DEPARTMENT OF HOMELAND SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM (DEPARTMENT OF HOMELAND SECURITY-OFFICE OF PERSONNEL MANAGEMENT) DEPARTMENT OF HOMELAND SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM Pay and Pay Administration Overview of Pay System § 9701.312 Maximum rates. (a) DHS may...

  14. Predicting Maximum Lake Depth from Surrounding Topography

    PubMed Central

    Hollister, Jeffrey W.; Milstead, W. Bryan; Urrutia, M. Andrea

    2011-01-01

    Information about lake morphometry (e.g., depth, volume, size, etc.) aids understanding of the physical and ecological dynamics of lakes, yet is often not readily available. The data needed to calculate measures of lake morphometry, particularly lake depth, are usually collected on a lake-by-lake basis and are difficult to obtain across broad regions. To span the gap between studies of individual lakes where detailed data exist and regional studies where access to useful data on lake depth is unavailable, we developed a method to predict maximum lake depth from the slope of the topography surrounding a lake. We use the National Elevation Dataset and the National Hydrography Dataset – Plus to estimate the percent slope of surrounding lakes and use this information to predict maximum lake depth. We also use field measured maximum lake depths from the US EPA's National Lakes Assessment to empirically adjust and cross-validate our predictions. We were able to predict maximum depth for ∼28,000 lakes in the Northeastern United States with an average cross-validated RMSE of 5.95 m and 5.09 m and average correlation of 0.82 and 0.69 for Hydrological Unit Code Regions 01 and 02, respectively. The depth predictions and the scripts are openly available as supplements to this manuscript. PMID:21984945

  15. Maximum Possible Transverse Velocity in Special Relativity.

    ERIC Educational Resources Information Center

    Medhekar, Sarang

    1991-01-01

    Using a physical picture, an expression for the maximum possible transverse velocity and orientation required for that by a linear emitter in special theory of relativity has been derived. A differential calculus method is also used to derive the expression. (Author/KR)

  16. Weak scale from the maximum entropy principle

    NASA Astrophysics Data System (ADS)

    Hamada, Yuta; Kawai, Hikaru; Kawana, Kiyoharu

    2015-03-01

    The theory of the multiverse and wormholes suggests that the parameters of the Standard Model (SM) are fixed in such a way that the radiation of the S3 universe at the final stage S_rad becomes maximum, which we call the maximum entropy principle. Although it is difficult to confirm this principle generally, for a few parameters of the SM, we can check whether S_rad actually becomes maximum at the observed values. In this paper, we regard S_rad at the final stage as a function of the weak scale (the Higgs expectation value) vh, and show that it becomes maximum around vh = {{O}} (300 GeV) when the dimensionless couplings in the SM, i.e., the Higgs self-coupling, the gauge couplings, and the Yukawa couplings are fixed. Roughly speaking, we find that the weak scale is given by vh ˜ T_{BBN}2 / (M_{pl}ye5), where ye is the Yukawa coupling of electron, T_BBN is the temperature at which the Big Bang nucleosynthesis starts, and M_pl is the Planck mass.

  17. 5 CFR 9701.312 - Maximum rates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Maximum rates. 9701.312 Section 9701.312 Administrative Personnel DEPARTMENT OF HOMELAND SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM (DEPARTMENT OF HOMELAND SECURITY-OFFICE OF PERSONNEL MANAGEMENT) DEPARTMENT OF HOMELAND SECURITY HUMAN...

  18. Comparing maximum pressures in internal combustion engines

    NASA Technical Reports Server (NTRS)

    Sparrow, Stanwood W; Lee, Stephen M

    1922-01-01

    Thin metal diaphragms form a satisfactory means for comparing maximum pressures in internal combustion engines. The diaphragm is clamped between two metal washers in a spark plug shell and its thickness is chosen such that, when subjected to explosion pressure, the exposed portion will be sheared from the rim in a short time.

  19. 24 CFR 200.15 - Maximum mortgage.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... DEVELOPMENT GENERAL INTRODUCTION TO FHA PROGRAMS Requirements for Application, Commitment, and Endorsement... 24 Housing and Urban Development 2 2012-04-01 2012-04-01 false Maximum mortgage. 200.15 Section 200.15 Housing and Urban Development Regulations Relating to Housing and Urban Development...

  20. 24 CFR 200.15 - Maximum mortgage.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DEVELOPMENT GENERAL INTRODUCTION TO FHA PROGRAMS Requirements for Application, Commitment, and Endorsement... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false Maximum mortgage. 200.15 Section 200.15 Housing and Urban Development Regulations Relating to Housing and Urban Development...

  1. Menu Plans: Maximum Nutrition for Minimum Cost.

    ERIC Educational Resources Information Center

    Texas Child Care, 1995

    1995-01-01

    Suggests that menu planning is the key to getting maximum nutrition in day care meals and snacks for minimum cost. Explores United States Department of Agriculture food pyramid guidelines for children and tips for planning menus and grocery shopping. Includes suggested meal patterns and portion sizes. (HTH)

  2. Enhanced absorption of Ag diamond-type nanoantenna arrays

    NASA Astrophysics Data System (ADS)

    Yuan, Zong-heng; Li, Xiao-nan; Guo, Ya-dong; Huang, Jing

    2015-01-01

    The optical metal nanoantenna on thin film solar cell is effective to enhance light absorption. In this paper, the diamond-type Ag nanoantenna arrays are proposed for increasing the efficiency of solar cells by localized surface plasmons resonance (LSPR). The effect of metal nanoantenna on the absorption enhancement is theoretically investigated by the finite difference time domain (FDTD) method. Broadband absorption enhancements in both visible and near-infrared regions are demonstrated in case of solar cell with diamond-type Ag nanoantennas. The spectral response is manipulated by geometrical parameters of the nanoantennas. The maximum enhancement factor of 1.51 for solar cell is obtained. For comparison, the other three nanoantennas are also analyzed. The results show that the solar cell with optimized diamond-type nanoantenna arrays is more efficient in optical absorption.

  3. Exploring the origin of high optical absorption in conjugated polymers.

    PubMed

    Vezie, Michelle S; Few, Sheridan; Meager, Iain; Pieridou, Galatia; Dörling, Bernhard; Ashraf, Raja Shahid; Goñi, Alejandro R; Bronstein, Hugo; McCulloch, Iain; Hayes, Sophia C; Campoy-Quiles, Mariano; Nelson, Jenny

    2016-07-01

    The specific optical absorption of an organic semiconductor is critical to the performance of organic optoelectronic devices. For example, higher light-harvesting efficiency can lead to higher photocurrent in solar cells that are limited by sub-optimal electrical transport. Here, we compare over 40 conjugated polymers, and find that many different chemical structures share an apparent maximum in their extinction coefficients. However, a diketopyrrolopyrrole-thienothiophene copolymer shows remarkably high optical absorption at relatively low photon energies. By investigating its backbone structure and conformation with measurements and quantum chemical calculations, we find that the high optical absorption can be explained by the high persistence length of the polymer. Accordingly, we demonstrate high absorption in other polymers with high theoretical persistence length. Visible light harvesting may be enhanced in other conjugated polymers through judicious design of the structure. PMID:27183327

  4. The 2011 Northern Hemisphere Solar Maximum

    NASA Astrophysics Data System (ADS)

    Altrock, Richard C.

    2013-01-01

    Altrock (1997, Solar Phys. 170, 411) discusses a process in which Fe XIV 530.3 nm emission features appear at high latitudes and gradually migrate towards the equator, merging with the sunspot "butterfly diagram". In cycles 21 - 23 solar maximum occurred when the number of Fe XIV emission regions per day > 0.19 (averaged over 365 days and both hemispheres) first reached latitudes 18°, 21° and 21°, for an average of 20° ± 1.7°. Another high-latitude process is the "Rush to the Poles" of polar crown prominences and their associated coronal emission, including Fe XIV. The Rush is a harbinger of solar maximum (cf. Altrock, 2003, Solar Phys. 216, 343). Solar maximum in cycles 21 - 23 occurred when the center line of the Rush reached a critical latitude. These latitudes were 76°, 74° and 78°, respectively, for an average of 76° ± 2°. Cycle 24 displays an intermittent Rush that is only well-defined in the northern hemisphere. In 2009 an initial slope of 4.6°/yr was found in the north, compared to an average of 9.4 ± 1.7 °/yr in the previous three cycles. However, in 2010 the slope increased to 7.5°/yr. Extending that rate to 76° ± 2° indicates that the solar maximum smoothed sunspot number in the northern hemisphere already occurred at 2011.6 ± 0.3. In the southern hemisphere the Rush is very poorly defined. A linear fit to several maxima would reach 76° in the south at 2014.2. In 1999, persistent Fe XIV coronal emission connected with the ESC appeared near 70° in the north and began migrating towards the equator at a rate 40% slower than the previous two solar cycles. A fit to the early ESC would not reach 20° until 2019.8. However, in 2009 and 2010 an acceleration occurred. Currently the greatest number of emission regions is at 21° in the north and 24°in the south. This indicates that solar maximum is occurring now in the north but not yet in the south. The latest global smoothed sunspot numbers show an inflection point in late 2011, which

  5. Speech processing using maximum likelihood continuity mapping

    SciTech Connect

    Hogden, John E.

    2000-01-01

    Speech processing is obtained that, given a probabilistic mapping between static speech sounds and pseudo-articulator positions, allows sequences of speech sounds to be mapped to smooth sequences of pseudo-articulator positions. In addition, a method for learning a probabilistic mapping between static speech sounds and pseudo-articulator position is described. The method for learning the mapping between static speech sounds and pseudo-articulator position uses a set of training data composed only of speech sounds. The said speech processing can be applied to various speech analysis tasks, including speech recognition, speaker recognition, speech coding, speech synthesis, and voice mimicry.

  6. Speech processing using maximum likelihood continuity mapping

    SciTech Connect

    Hogden, J.E.

    2000-04-18

    Speech processing is obtained that, given a probabilistic mapping between static speech sounds and pseudo-articulator positions, allows sequences of speech sounds to be mapped to smooth sequences of pseudo-articulator positions. In addition, a method for learning a probabilistic mapping between static speech sounds and pseudo-articulator position is described. The method for learning the mapping between static speech sounds and pseudo-articulator position uses a set of training data composed only of speech sounds. The said speech processing can be applied to various speech analysis tasks, including speech recognition, speaker recognition, speech coding, speech synthesis, and voice mimicry.

  7. Solar maximum mission panel jettison analysis remote manipulator system

    NASA Technical Reports Server (NTRS)

    Bauer, R. B.

    1980-01-01

    A study is presented of the development of the Remote Manipulator System (RMS) configurations for jettison of the solar panels on the Solar Maximum Mission/Multimission Satellite. A valid RMS maneuver between jettison configurations was developed. Arm and longeron loads and effector excursions due to the solar panel jettison were determined to see if they were within acceptable limits. These loads and end effector excursions were analyzed under two RMS modes, servos active in position hold submode, and in the brakes on mode.

  8. Theory and application of maximum magnetic energy in toroidal plasmas

    SciTech Connect

    Chu, T.K.

    1992-02-01

    The magnetic energy in an inductively driven steady-state toroidal plasma is a maximum for a given rate of dissipation of energy (Poynting flux). A purely resistive steady state of the piecewise force-free configuration, however, cannot exist, as the periodic removal of the excess poloidal flux and pressure, due to heating, ruptures the static equilibrium of the partitioning rational surfaces intermittently. The rupture necessitates a plasma with a negative q{prime}/q (as in reverse field pinches and spheromaks) to have the same {alpha} in all its force-free regions and with a positive q{prime}/q (as in tokamaks) to have centrally peaked {alpha}'s.

  9. Theory and application of maximum magnetic energy in toroidal plasmas

    SciTech Connect

    Chu, T.K.

    1992-02-01

    The magnetic energy in an inductively driven steady-state toroidal plasma is a maximum for a given rate of dissipation of energy (Poynting flux). A purely resistive steady state of the piecewise force-free configuration, however, cannot exist, as the periodic removal of the excess poloidal flux and pressure, due to heating, ruptures the static equilibrium of the partitioning rational surfaces intermittently. The rupture necessitates a plasma with a negative q{prime}/q (as in reverse field pinches and spheromaks) to have the same {alpha} in all its force-free regions and with a positive q{prime}/q (as in tokamaks) to have centrally peaked {alpha}`s.

  10. Minimum cause--maximum effect: the travelogue of a bullet.

    PubMed

    Hartert, Marc; Dahm, Manfred; Neufang, Achim; Vahl, Christian-Friedrich

    2010-11-01

    This case report involves a 57-year-old male, accidentally shot in the chest with a small bore firearm. The bullet entered the left hemithorax, disrupting the left internal mammarian artery. It then penetrated the anterior wall of the right ventricle causing a pericardial tamponade. After leaving the base of the right heart it perforated the diaphragm, the liver, the spleen and the pancreas. Finally, it penetrated the abdominal aorta 3 cm proximally to the coeliac trunk and reached its final position paravertebrally. This case report illustrates that the management of even minimum gunshot wounds requires a maximum variety of surgical skills. PMID:20709697

  11. CO2 Laser Absorption in Ablation Plasmas

    SciTech Connect

    Eckel, Hans-Albert; Tegel, Jochen; Schall, Wolfgang O.

    2006-05-02

    The impulse formation by laser ablation is limited by the premature absorption of the incident laser radiation in the initially produced cloud of ablation products. The power fraction of a CO2 laser pulse transmitted through a small hole in a POM sample for pulse energies of 35 to 150 J focused on a spot of 2 cm2 has been compared with the incident power. The plasma formation in vacuum and in air of 3500 Pa and the spread of the shock wave with velocities of 1.6 to 2.4 km/s in the low pressure air was observed by Schlieren photography. A sharp edged dark zone with a maximum extension of 10 to 12 mm away from the target surface develops within 5 {mu}s independently of the pressure and is assumed to be a plasma. In order to find out, if this is also the zone where the majority of the incident laser radiation is absorbed, a CO2 probe laser beam was directed through the expansion cloud parallel to and at various distances from the sample surface. The time behavior of the absorption signal of the probe beam has been measured and an absorption wave could be observed.

  12. Absorption spectra of cold dilute solid solutions

    SciTech Connect

    Holland, R.F.; Maier, W.B. II; Freund, S.; Beattie, W.H.

    1983-06-01

    Infrared absorption spectra have been obtained for some compounds trapped in crystalline solids by freezing liquid Xe, Kr, Ar, or CH/sub 4/ solutions. The optical quality of the solid solutions is good, and they have been cooled to approx.80 K in 1.35 cm sample thicknesses to study the absorption in fundamental vibrational bands of the solutes. In the cases discussed, the bands are narrow, with observed full widths at half-maximum absorbance 0.05--0.30 cm/sup -1/ greater than the instrumental resolution (0.18--0.29 cm/sup -1/). The spectra appear to be free of ''multiple site'' and solute aggregate absorptions. Spectra displaying isotropic splitting in bands of natural BCl/sub 3/, SeF/sub 6/, OsO/sub 4/, TiCl/sub 4/, and MoF/sub 6/ are presented, and band frequencies are compared with some results obtained in evaporative matrices, in the gas phase, and in liquid solutions. For this comparison we have obtained some spectra of SeF/sub 6/ and BCl/sub 3/ gas.

  13. Terahertz absorption of dilute aqueous solutions

    NASA Astrophysics Data System (ADS)

    Heyden, Matthias; Tobias, Douglas J.; Matyushov, Dmitry V.

    2012-12-01

    Absorption of terahertz (THz) radiation by aqueous solutions of large solutes reports on the polarization response of their hydration shells. This is because the dipolar relaxation of the solute is dynamically frozen at these frequencies, and most of the solute-induced absorption changes, apart from the expulsion of water, are caused by interfacial water. We propose a model expressing the dipolar response of solutions in terms of a single parameter, the interface dipole moment induced in the interfacial water by electromagnetic radiation. We apply this concept to experimental THz absorption of hydrated sugars, amino acids, and proteins. None of the solutes studied here follow the expectations of dielectric theories, which predict a negative projection of the interface dipole on the external electric field. We find that this prediction is not able to describe the available experimental data, which instead suggests a nearly zero interface dipole for sugars and a more diverse pattern for amino acids. Hydrophobic amino acids, similarly to sugars, give rise to near zero interface dipoles, while strongly hydrophilic ones are best described by a positive projection of the interface dipole on the external field. The sign of the interface dipole is connected to the slope of the absorption coefficient with the solute concentration. A positive slope, implying an increase in the solution polarity relative to water, mirrors results frequently reported for protein solutions. We therefore use molecular dynamics simulations of hydrated glucose and lambda repressor protein to calculate the interface dipole moments of these solutes and the concentration dependence of the THz absorption. The absorption at THz frequencies increases with increasing solute concentration in both cases, implying a higher polarity of the solution compared to bulk water. The structure of the hydration layer, extracted from simulations, is qualitatively similar in both cases, with spatial correlations

  14. Effect of partial absorption on diffusion with resetting

    NASA Astrophysics Data System (ADS)

    Whitehouse, Justin; Evans, Martin R.; Majumdar, Satya N.

    2013-02-01

    The effect of partial absorption on a diffusive particle which stochastically resets its position with a finite rate r is considered. The particle is absorbed by a target at the origin with absorption “velocity” a; as the velocity a approaches ∞ the absorption property of the target approaches that of a perfectly absorbing target. The effect of partial absorption on first-passage time problems is studied, in particular, it is shown that the mean time to absorption (MTA) is increased by an additive term proportional to 1/a. The results are extended to multiparticle systems where independent searchers, initially uniformly distributed with a given density, look for a single immobile target. It is found that the average survival probability Pav is modified by a multiplicative factor which is a function of 1/a, whereas the decay rate of the typical survival probability Ptyp is decreased by an additive term proportional to 1/a.

  15. 75 FR 43840 - Inflation Adjustment of the Ordinary Maximum and Aggravated Maximum Civil Monetary Penalties for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-27

    ... civil monetary penalties per the Inflation Act. See 74 FR 68701 (December 29, 2009). FRA's maximum and... materials violation was $275. 69 FR 30590, May 28, 2004. To implement these SAFETEA-LU amendments to the maximum and minimum penalties, FRA issued a final rule that was published on December 26, 2006, 71...

  16. Theoretical Analysis of Maximum Flow Declination Rate versus Maximum Area Declination Rate in Phonation

    ERIC Educational Resources Information Center

    Titze, Ingo R.

    2006-01-01

    Purpose: Maximum flow declination rate (MFDR) in the glottis is known to correlate strongly with vocal intensity in voicing. This declination, or negative slope on the glottal airflow waveform, is in part attributable to the maximum area declination rate (MADR) and in part to the overall inertia of the air column of the vocal tract (lungs to…

  17. 76 FR 1504 - Pipeline Safety: Establishing Maximum Allowable Operating Pressure or Maximum Operating Pressure...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-10

    ...PHMSA is issuing an Advisory Bulletin to remind operators of gas and hazardous liquid pipeline facilities of their responsibilities, under Federal integrity management (IM) regulations, to perform detailed threat and risk analyses that integrate accurate data and information from their entire pipeline system, especially when calculating Maximum Allowable Operating Pressure (MAOP) or Maximum......

  18. Detection of water vapour absorption around 363nm in measured atmospheric absorption spectra and its effect on DOAS evaluations

    NASA Astrophysics Data System (ADS)

    Lampel, Johannes; Polyansky, Oleg. L.; Kyuberis, Alexandra A.; Zobov, Nikolai F.; Tennyson, Jonathan; Lodi, Lorenzo; Pöhler, Denis; Frieß, Udo; Platt, Ulrich; Beirle, Steffen; Wagner, Thomas

    2016-04-01

    Water vapour is known to absorb light from the microwave region to the blue part of the visible spectrum at a decreasing magnitude. Ab-initio approaches to model individual absorption lines of the gaseous water molecule predict absorption lines until its dissociation limit at 243 nm. We present first evidence of water vapour absorption at 363 nm from field measurements based on the POKAZATEL absorption line list by Polyansky et al. (2016) using data from Multi-Axis differential optical absorption spectroscopy (MAX-DOAS) and Longpath (LP)-DOAS measurements. The predicted absorptions contribute significantly to the observed optical depths with up to 2 × 10‑3. Their magnitude correlates well (R2 = 0.89) to simultaneously measured well-established water vapour absorptions in the blue spectral range from 452-499 nm, but is underestimated by a factor of 2.6 ± 0.6 in the ab-initio model. At a spectral resolution of 0.5nm this leads to a maximum absorption cross-section value of 5.4 × 10‑27 cm2/molec at 362.3nm. The results are independent of the employed cross-section data to compensate for the overlayed absorption of the oxygen dimer O4. The newly found absorption can have a significant impact on the spectral retrieval of absorbing trace-gas species in the spectral range around 363 nm. Its effect on the spectral analysis of O4, HONO and OClO are discussed.

  19. Pareto versus lognormal: A maximum entropy test

    NASA Astrophysics Data System (ADS)

    Bee, Marco; Riccaboni, Massimo; Schiavo, Stefano

    2011-08-01

    It is commonly found that distributions that seem to be lognormal over a broad range change to a power-law (Pareto) distribution for the last few percentiles. The distributions of many physical, natural, and social events (earthquake size, species abundance, income and wealth, as well as file, city, and firm sizes) display this structure. We present a test for the occurrence of power-law tails in statistical distributions based on maximum entropy. This methodology allows one to identify the true data-generating processes even in the case when it is neither lognormal nor Pareto. The maximum entropy approach is then compared with other widely used methods and applied to different levels of aggregation of complex systems. Our results provide support for the theory that distributions with lognormal body and Pareto tail can be generated as mixtures of lognormally distributed units.

  20. Model Fit after Pairwise Maximum Likelihood

    PubMed Central

    Barendse, M. T.; Ligtvoet, R.; Timmerman, M. E.; Oort, F. J.

    2016-01-01

    Maximum likelihood factor analysis of discrete data within the structural equation modeling framework rests on the assumption that the observed discrete responses are manifestations of underlying continuous scores that are normally distributed. As maximizing the likelihood of multivariate response patterns is computationally very intensive, the sum of the log–likelihoods of the bivariate response patterns is maximized instead. Little is yet known about how to assess model fit when the analysis is based on such a pairwise maximum likelihood (PML) of two–way contingency tables. We propose new fit criteria for the PML method and conduct a simulation study to evaluate their performance in model selection. With large sample sizes (500 or more), PML performs as well the robust weighted least squares analysis of polychoric correlations. PMID:27148136

  1. Maximum-entropy description of animal movement.

    PubMed

    Fleming, Chris H; Subaşı, Yiğit; Calabrese, Justin M

    2015-03-01

    We introduce a class of maximum-entropy states that naturally includes within it all of the major continuous-time stochastic processes that have been applied to animal movement, including Brownian motion, Ornstein-Uhlenbeck motion, integrated Ornstein-Uhlenbeck motion, a recently discovered hybrid of the previous models, and a new model that describes central-place foraging. We are also able to predict a further hierarchy of new models that will emerge as data quality improves to better resolve the underlying continuity of animal movement. Finally, we also show that Langevin equations must obey a fluctuation-dissipation theorem to generate processes that fall from this class of maximum-entropy distributions when the constraints are purely kinematic. PMID:25871054

  2. Maximum-entropy description of animal movement

    NASA Astrophysics Data System (ADS)

    Fleming, Chris H.; Subaşı, Yiǧit; Calabrese, Justin M.

    2015-03-01

    We introduce a class of maximum-entropy states that naturally includes within it all of the major continuous-time stochastic processes that have been applied to animal movement, including Brownian motion, Ornstein-Uhlenbeck motion, integrated Ornstein-Uhlenbeck motion, a recently discovered hybrid of the previous models, and a new model that describes central-place foraging. We are also able to predict a further hierarchy of new models that will emerge as data quality improves to better resolve the underlying continuity of animal movement. Finally, we also show that Langevin equations must obey a fluctuation-dissipation theorem to generate processes that fall from this class of maximum-entropy distributions when the constraints are purely kinematic.

  3. Zipf's law, power laws and maximum entropy

    NASA Astrophysics Data System (ADS)

    Visser, Matt

    2013-04-01

    Zipf's law, and power laws in general, have attracted and continue to attract considerable attention in a wide variety of disciplines—from astronomy to demographics to software structure to economics to linguistics to zoology, and even warfare. A recent model of random group formation (RGF) attempts a general explanation of such phenomena based on Jaynes' notion of maximum entropy applied to a particular choice of cost function. In the present paper I argue that the specific cost function used in the RGF model is in fact unnecessarily complicated, and that power laws can be obtained in a much simpler way by applying maximum entropy ideas directly to the Shannon entropy subject only to a single constraint: that the average of the logarithm of the observable quantity is specified.

  4. A Maximum Radius for Habitable Planets.

    PubMed

    Alibert, Yann

    2015-09-01

    We compute the maximum radius a planet can have in order to fulfill two constraints that are likely necessary conditions for habitability: 1- surface temperature and pressure compatible with the existence of liquid water, and 2- no ice layer at the bottom of a putative global ocean, that would prevent the operation of the geologic carbon cycle to operate. We demonstrate that, above a given radius, these two constraints cannot be met: in the Super-Earth mass range (1-12 Mearth), the overall maximum that a planet can have varies between 1.8 and 2.3 Rearth. This radius is reduced when considering planets with higher Fe/Si ratios, and taking into account irradiation effects on the structure of the gas envelope. PMID:26159097

  5. Evaluation of the Maximum Allowable Cost Program

    PubMed Central

    Lee, A. James; Hefner, Dennis; Dobson, Allen; Hardy, Ralph

    1983-01-01

    This article summarizes an evaluation of the Maximum Allowable Cost (MAC)-Estimated Acquisition Cost (EAC) program, the Federal Government's cost-containment program for prescription drugs.1 The MAC-EAC regulations which became effective on August 26, 1976, have four major components: (1) Maximum Allowable Cost reimbursement limits for selected multisource or generically available drugs; (2) Estimated Acquisition Cost reimbursement limits for all drugs; (3) “usual and customary” reimbursement limits for all drugs; and (4) a directive that professional fee studies be performed by each State. The study examines the benefits and costs of the MAC reimbursement limits for 15 dosage forms of five multisource drugs and EAC reimbursement limits for all drugs for five selected States as of 1979. PMID:10309857

  6. Maximum independent set on diluted triangular lattices.

    PubMed

    Fay, C W; Liu, J W; Duxbury, P M

    2006-05-01

    Core percolation and maximum independent set on random graphs have recently been characterized using the methods of statistical physics. Here we present a statistical physics study of these problems on bond diluted triangular lattices. Core percolation critical behavior is found to be consistent with the standard percolation values, though there are strong finite size effects. A transfer matrix method is developed and applied to find accurate values of the density and degeneracy of the maximum independent set on lattices of limited width but large length. An extrapolation of these results to the infinite lattice limit yields high precision results, which are tabulated. These results are compared to results found using both vertex based and edge based local probability recursion algorithms, which have proven useful in the analysis of hard computational problems, such as the satisfiability problem. PMID:16803003

  7. Model Fit after Pairwise Maximum Likelihood.

    PubMed

    Barendse, M T; Ligtvoet, R; Timmerman, M E; Oort, F J

    2016-01-01

    Maximum likelihood factor analysis of discrete data within the structural equation modeling framework rests on the assumption that the observed discrete responses are manifestations of underlying continuous scores that are normally distributed. As maximizing the likelihood of multivariate response patterns is computationally very intensive, the sum of the log-likelihoods of the bivariate response patterns is maximized instead. Little is yet known about how to assess model fit when the analysis is based on such a pairwise maximum likelihood (PML) of two-way contingency tables. We propose new fit criteria for the PML method and conduct a simulation study to evaluate their performance in model selection. With large sample sizes (500 or more), PML performs as well the robust weighted least squares analysis of polychoric correlations. PMID:27148136

  8. Cloud absorption radiometer

    NASA Technical Reports Server (NTRS)

    Strange, M. G.

    1988-01-01

    The Cloud Absorption Radiometer (CAR) was developed to measure spectrally how light is scattered by clouds and to determine the single scattering albedo, important to meteorology and climate studies, with unprecedented accuracy. This measurement is based on ratios of downwelling to upwelling radiation within clouds, and so is not strongly dependent upon absolute radiometric calibration of the instrument. The CAR has a 5-inch aperture and 1 degree IFOV, and spatially scans in a plane orthogonal to the flight vector from the zenith to nadir at 1.7 revolutions per second. Incoming light is measured in 13 spectral bands, using silicon, germanium, and indium-antimonide detectors. Data from each channel is digitally recorded in flight with 10-bit (0.1 percent) resolution. The instrument incorporates several novel features. These features are briefly detailed.

  9. Analyzing Water's Optical Absorption

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A cooperative agreement between World Precision Instruments (WPI), Inc., and Stennis Space Center has led the UltraPath(TM) device, which provides a more efficient method for analyzing the optical absorption of water samples at sea. UltraPath is a unique, high-performance absorbance spectrophotometer with user-selectable light path lengths. It is an ideal tool for any study requiring precise and highly sensitive spectroscopic determination of analytes, either in the laboratory or the field. As a low-cost, rugged, and portable system capable of high- sensitivity measurements in widely divergent waters, UltraPath will help scientists examine the role that coastal ocean environments play in the global carbon cycle. UltraPath(TM) is a trademark of World Precision Instruments, Inc. LWCC(TM) is a trademark of World Precision Instruments, Inc.

  10. Evaluating foot kinematics using magnetic resonance imaging: from maximum plantar flexion, inversion, and internal rotation to maximum dorsiflexion, eversion, and external rotation.

    PubMed

    Fassbind, Michael J; Rohr, Eric S; Hu, Yangqiu; Haynor, David R; Siegler, Sorin; Sangeorzan, Bruce J; Ledoux, William R

    2011-10-01

    The foot consists of many small bones with complicated joints that guide and limit motion. A variety of invasive and noninvasive means [mechanical, X-ray stereophotogrammetry, electromagnetic sensors, retro-reflective motion analysis, computer tomography (CT), and magnetic resonance imaging (MRI)] have been used to quantify foot bone motion. In the current study we used a foot plate with an electromagnetic sensor to determine an individual subject's foot end range of motion (ROM) from maximum plantar flexion, internal rotation, and inversion to maximum plantar flexion, inversion, and internal rotation to maximum dorsiflexion, eversion, and external rotation. We then used a custom built MRI-compatible device to hold each subject's foot during scanning in eight unique positions determined from the end ROM data. The scan data were processed using software that allowed the bones to be segmented with the foot in the neutral position and the bones in the other seven positions to be registered to their base positions with minimal user intervention. Bone to bone motion was quantified using finite helical axes (FHA). FHA for the talocrural, talocalcaneal, and talonavicular joints compared well to published studies, which used a variety of technologies and input motions. This study describes a method for quantifying foot bone motion from maximum plantar flexion, inversion, and internal rotation to maximum dorsiflexion, eversion, and external rotation with relatively little user processing time. PMID:22070336

  11. Tissue Radiation Response with Maximum Tsallis Entropy

    SciTech Connect

    Sotolongo-Grau, O.; Rodriguez-Perez, D.; Antoranz, J. C.; Sotolongo-Costa, Oscar

    2010-10-08

    The expression of survival factors for radiation damaged cells is currently based on probabilistic assumptions and experimentally fitted for each tumor, radiation, and conditions. Here, we show how the simplest of these radiobiological models can be derived from the maximum entropy principle of the classical Boltzmann-Gibbs expression. We extend this derivation using the Tsallis entropy and a cutoff hypothesis, motivated by clinical observations. The obtained expression shows a remarkable agreement with the experimental data found in the literature.

  12. Maximum entropy production - Full steam ahead

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph D.

    2012-05-01

    The application of a principle of Maximum Entropy Production (MEP, or less ambiguously MaxEP) to planetary climate is discussed. This idea suggests that if sufficiently free of dynamical constraints, the atmospheric and oceanic heat flows across a planet may conspire to maximize the generation of mechanical work, or entropy. Thermodynamic and information-theoretic aspects of this idea are discussed. These issues are also discussed in the context of dust devils, convective vortices found in strongly-heated desert areas.

  13. Maximum entropy and Bayesian methods. Proceedings.

    NASA Astrophysics Data System (ADS)

    Grandy, W. T., Jr.; Schick, L. H.

    This volume contains a selection of papers presented at the Tenth Annual Workshop on Maximum Entropy and Bayesian Methods. The thirty-six papers included cover a wide range of applications in areas such as economics and econometrics, astronomy and astrophysics, general physics, complex systems, image reconstruction, and probability and mathematics. Together they give an excellent state-of-the-art overview of fundamental methods of data analysis.

  14. Sensor registration using airlanes: maximum likelihood solution

    NASA Astrophysics Data System (ADS)

    Ong, Hwa-Tung

    2004-01-01

    In this contribution, the maximum likelihood estimation of sensor registration parameters, such as range, azimuth and elevation biases in radar measurements, using airlane information is proposed and studied. The motivation for using airlane information for sensor registration is that it is freely available as a source of reference and it provides an alternative to conventional techniques that rely on synchronised and correctly associated measurements from two or more sensors. In the paper, the problem is first formulated in terms of a measurement model that is a nonlinear function of the unknown target state and sensor parameters, plus sensor noise. A probabilistic model of the target state is developed based on airlane information. The maximum likelihood and also maximum a posteriori solutions are given. The Cramer-Rao lower bound is derived and simulation results are presented for the case of estimating the biases in radar range, azimuth and elevation measurements. The accuracy of the proposed method is compared against the Cramer-Rao lower bound and that of an existing two-sensor alignment method. It is concluded that sensor registration using airlane information is a feasible alternative to existing techniques.

  15. Sensor registration using airlanes: maximum likelihood solution

    NASA Astrophysics Data System (ADS)

    Ong, Hwa-Tung

    2003-12-01

    In this contribution, the maximum likelihood estimation of sensor registration parameters, such as range, azimuth and elevation biases in radar measurements, using airlane information is proposed and studied. The motivation for using airlane information for sensor registration is that it is freely available as a source of reference and it provides an alternative to conventional techniques that rely on synchronised and correctly associated measurements from two or more sensors. In the paper, the problem is first formulated in terms of a measurement model that is a nonlinear function of the unknown target state and sensor parameters, plus sensor noise. A probabilistic model of the target state is developed based on airlane information. The maximum likelihood and also maximum a posteriori solutions are given. The Cramer-Rao lower bound is derived and simulation results are presented for the case of estimating the biases in radar range, azimuth and elevation measurements. The accuracy of the proposed method is compared against the Cramer-Rao lower bound and that of an existing two-sensor alignment method. It is concluded that sensor registration using airlane information is a feasible alternative to existing techniques.

  16. The maximum rate of mammal evolution.

    PubMed

    Evans, Alistair R; Jones, David; Boyer, Alison G; Brown, James H; Costa, Daniel P; Ernest, S K Morgan; Fitzgerald, Erich M G; Fortelius, Mikael; Gittleman, John L; Hamilton, Marcus J; Harding, Larisa E; Lintulaakso, Kari; Lyons, S Kathleen; Okie, Jordan G; Saarinen, Juha J; Sibly, Richard M; Smith, Felisa A; Stephens, Patrick R; Theodor, Jessica M; Uhen, Mark D

    2012-03-13

    How fast can a mammal evolve from the size of a mouse to the size of an elephant? Achieving such a large transformation calls for major biological reorganization. Thus, the speed at which this occurs has important implications for extensive faunal changes, including adaptive radiations and recovery from mass extinctions. To quantify the pace of large-scale evolution we developed a metric, clade maximum rate, which represents the maximum evolutionary rate of a trait within a clade. We applied this metric to body mass evolution in mammals over the last 70 million years, during which multiple large evolutionary transitions occurred in oceans and on continents and islands. Our computations suggest that it took a minimum of 1.6, 5.1, and 10 million generations for terrestrial mammal mass to increase 100-, and 1,000-, and 5,000-fold, respectively. Values for whales were down to half the length (i.e., 1.1, 3, and 5 million generations), perhaps due to the reduced mechanical constraints of living in an aquatic environment. When differences in generation time are considered, we find an exponential increase in maximum mammal body mass during the 35 million years following the Cretaceous-Paleogene (K-Pg) extinction event. Our results also indicate a basic asymmetry in macroevolution: very large decreases (such as extreme insular dwarfism) can happen at more than 10 times the rate of increases. Our findings allow more rigorous comparisons of microevolutionary and macroevolutionary patterns and processes. PMID:22308461

  17. The maximum rate of mammal evolution

    NASA Astrophysics Data System (ADS)

    Evans, Alistair R.; Jones, David; Boyer, Alison G.; Brown, James H.; Costa, Daniel P.; Ernest, S. K. Morgan; Fitzgerald, Erich M. G.; Fortelius, Mikael; Gittleman, John L.; Hamilton, Marcus J.; Harding, Larisa E.; Lintulaakso, Kari; Lyons, S. Kathleen; Okie, Jordan G.; Saarinen, Juha J.; Sibly, Richard M.; Smith, Felisa A.; Stephens, Patrick R.; Theodor, Jessica M.; Uhen, Mark D.

    2012-03-01

    How fast can a mammal evolve from the size of a mouse to the size of an elephant? Achieving such a large transformation calls for major biological reorganization. Thus, the speed at which this occurs has important implications for extensive faunal changes, including adaptive radiations and recovery from mass extinctions. To quantify the pace of large-scale evolution we developed a metric, clade maximum rate, which represents the maximum evolutionary rate of a trait within a clade. We applied this metric to body mass evolution in mammals over the last 70 million years, during which multiple large evolutionary transitions occurred in oceans and on continents and islands. Our computations suggest that it took a minimum of 1.6, 5.1, and 10 million generations for terrestrial mammal mass to increase 100-, and 1,000-, and 5,000-fold, respectively. Values for whales were down to half the length (i.e., 1.1, 3, and 5 million generations), perhaps due to the reduced mechanical constraints of living in an aquatic environment. When differences in generation time are considered, we find an exponential increase in maximum mammal body mass during the 35 million years following the Cretaceous-Paleogene (K-Pg) extinction event. Our results also indicate a basic asymmetry in macroevolution: very large decreases (such as extreme insular dwarfism) can happen at more than 10 times the rate of increases. Our findings allow more rigorous comparisons of microevolutionary and macroevolutionary patterns and processes.

  18. Maximum-biomass prediction of homofermentative Lactobacillus.

    PubMed

    Cui, Shumao; Zhao, Jianxin; Liu, Xiaoming; Chen, Yong Q; Zhang, Hao; Chen, Wei

    2016-07-01

    Fed-batch and pH-controlled cultures have been widely used for industrial production of probiotics. The aim of this study was to systematically investigate the relationship between the maximum biomass of different homofermentative Lactobacillus and lactate accumulation, and to develop a prediction equation for the maximum biomass concentration in such cultures. The accumulation of the end products and the depletion of nutrients by various strains were evaluated. In addition, the minimum inhibitory concentrations (MICs) of acid anions for various strains at pH 7.0 were examined. The lactate concentration at the point of complete inhibition was not significantly different from the MIC of lactate for all of the strains, although the inhibition mechanism of lactate and acetate on Lactobacillus rhamnosus was different from the other strains which were inhibited by the osmotic pressure caused by acid anions at pH 7.0. When the lactate concentration accumulated to the MIC, the strains stopped growing. The maximum biomass was closely related to the biomass yield per unit of lactate produced (YX/P) and the MIC (C) of lactate for different homofermentative Lactobacillus. Based on the experimental data obtained using different homofermentative Lactobacillus, a prediction equation was established as follows: Xmax - X0 = (0.59 ± 0.02)·YX/P·C. PMID:26896862

  19. "SPURS" in the North Atlantic Salinity Maximum

    NASA Astrophysics Data System (ADS)

    Schmitt, Raymond

    2014-05-01

    The North Atlantic Salinity Maximum is the world's saltiest open ocean salinity maximum and was the focus of the recent Salinity Processes Upper-ocean Regional Study (SPURS) program. SPURS was a joint venture between US, French, Irish, and Spanish investigators. Three US and two EU cruises were involved from August, 1012 - October, 2013 as well as surface moorings, glider, drifter and float deployments. Shipboard operations included underway meteorological and oceanic data, hydrographic surveys and turbulence profiling. The goal is to improve our understanding of how the salinity maximum is maintained and how it may be changing. It is formed by an excess of evaporation over precipitation and the wind-driven convergence of the subtropical gyre. Such salty areas are getting saltier with global warming (a record high SSS was observed in SPURS) and it is imperative to determine the relative roles of surface water fluxes and oceanic processes in such trends. The combination of accurate surface flux estimates with new assessments of vertical and horizontal mixing in the ocean will help elucidate the utility of ocean salinity in quantifying the changing global water cycle.

  20. Maximum entropy analysis of cosmic ray composition

    NASA Astrophysics Data System (ADS)

    Nosek, Dalibor; Ebr, Jan; Vícha, Jakub; Trávníček, Petr; Nosková, Jana

    2016-03-01

    We focus on the primary composition of cosmic rays with the highest energies that cause extensive air showers in the Earth's atmosphere. A way of examining the two lowest order moments of the sample distribution of the depth of shower maximum is presented. The aim is to show that useful information about the composition of the primary beam can be inferred with limited knowledge we have about processes underlying these observations. In order to describe how the moments of the depth of shower maximum depend on the type of primary particles and their energies, we utilize a superposition model. Using the principle of maximum entropy, we are able to determine what trends in the primary composition are consistent with the input data, while relying on a limited amount of information from shower physics. Some capabilities and limitations of the proposed method are discussed. In order to achieve a realistic description of the primary mass composition, we pay special attention to the choice of the parameters of the superposition model. We present two examples that demonstrate what consequences can be drawn for energy dependent changes in the primary composition.

  1. A Maximum Entropy Formalism for Disentangling Chains of Correlated Sequence Positions

    SciTech Connect

    Lapedes, A.S.; Giraud, B.G.; Liu, L.C.; Stormo, G.D.

    1998-08-03

    Covariation analysis of sets of aligned sequences of protein molecules is successful in certain instances in elucidating certain structural and functional links, but in general, pairs of sites displaying highly covarying mutations in protein sequences do not necessarily correspond to sites that are spatially close in the protein structure. In contrast, covariation analysis of sets of aligned sequences for RNA molecules is relatively successful in elucidating RNA secondary structure, as well as some aspects of tertiary structure. The goals of this paper are to (1) present the problem, (2) develop the mathematical formalism for solving the problem, and (3) validate the resulting algorithms on simulated data. Extensive application to biological sequences will be presented elsewhere.

  2. Percutaneous absorption in preterm infants.

    PubMed

    West, D P; Halket, J M; Harvey, D R; Hadgraft, J; Solomon, L M; Harper, J I

    1987-11-01

    The skin of preterm infants varies considerably in its level of maturity. To understand skin absorption in premature infants better, we report a technique for the assessment of percutaneous absorption at various gestational and postnatal ages using stable, isotope-labeled (13C6) benzoic acid. Our results indicate that in the preterm infant, this method detects enhanced skin absorption in the first postnatal days, which declines over three weeks to that expected of a full-term infant. This approach also indicates an inverse relationship between gestational age and skin absorption, as well as postnatal age and skin absorption. The reported technique is a safe and noninvasive method using a model skin penetrant for the study of percutaneous absorption in preterm infants from which basic data may be derived to add to our understanding of skin barrier function. PMID:3422856

  3. Protonation effects on the UV/Vis absorption spectra of imatinib: A theoretical and experimental study

    NASA Astrophysics Data System (ADS)

    Grante, Ilze; Actins, Andris; Orola, Liana

    2014-08-01

    An experimental and theoretical investigation of protonation effects on the UV/Vis absorption spectra of imatinib showed systematic changes of absorption depending on the pH, and a new absorption band appeared below pH 2. These changes in the UV/Vis absorption spectra were interpreted using quantum chemical calculations. The geometry of various imatinib cations in the gas phase and in ethanol solution was optimized with the DFT/B3LYP method. The resultant geometries were compared to the experimentally determined crystal structures of imatinib salts. The semi-empirical ZINDO-CI method was employed to calculate the absorption lines and electronic transitions. Our study suggests that the formation of the extra near-UV absorption band resulted from an increase of imatinib trication concentration in the solution, while the rapid increase of the first absorption maximum could be attributed to both the formation of imatinib trication and tetracation.

  4. Collaborative double robust targeted maximum likelihood estimation.

    PubMed

    van der Laan, Mark J; Gruber, Susan

    2010-01-01

    Collaborative double robust targeted maximum likelihood estimators represent a fundamental further advance over standard targeted maximum likelihood estimators of a pathwise differentiable parameter of a data generating distribution in a semiparametric model, introduced in van der Laan, Rubin (2006). The targeted maximum likelihood approach involves fluctuating an initial estimate of a relevant factor (Q) of the density of the observed data, in order to make a bias/variance tradeoff targeted towards the parameter of interest. The fluctuation involves estimation of a nuisance parameter portion of the likelihood, g. TMLE has been shown to be consistent and asymptotically normally distributed (CAN) under regularity conditions, when either one of these two factors of the likelihood of the data is correctly specified, and it is semiparametric efficient if both are correctly specified. In this article we provide a template for applying collaborative targeted maximum likelihood estimation (C-TMLE) to the estimation of pathwise differentiable parameters in semi-parametric models. The procedure creates a sequence of candidate targeted maximum likelihood estimators based on an initial estimate for Q coupled with a succession of increasingly non-parametric estimates for g. In a departure from current state of the art nuisance parameter estimation, C-TMLE estimates of g are constructed based on a loss function for the targeted maximum likelihood estimator of the relevant factor Q that uses the nuisance parameter to carry out the fluctuation, instead of a loss function for the nuisance parameter itself. Likelihood-based cross-validation is used to select the best estimator among all candidate TMLE estimators of Q(0) in this sequence. A penalized-likelihood loss function for Q is suggested when the parameter of interest is borderline-identifiable. We present theoretical results for "collaborative double robustness," demonstrating that the collaborative targeted maximum

  5. Collaborative Double Robust Targeted Maximum Likelihood Estimation*

    PubMed Central

    van der Laan, Mark J.; Gruber, Susan

    2010-01-01

    Collaborative double robust targeted maximum likelihood estimators represent a fundamental further advance over standard targeted maximum likelihood estimators of a pathwise differentiable parameter of a data generating distribution in a semiparametric model, introduced in van der Laan, Rubin (2006). The targeted maximum likelihood approach involves fluctuating an initial estimate of a relevant factor (Q) of the density of the observed data, in order to make a bias/variance tradeoff targeted towards the parameter of interest. The fluctuation involves estimation of a nuisance parameter portion of the likelihood, g. TMLE has been shown to be consistent and asymptotically normally distributed (CAN) under regularity conditions, when either one of these two factors of the likelihood of the data is correctly specified, and it is semiparametric efficient if both are correctly specified. In this article we provide a template for applying collaborative targeted maximum likelihood estimation (C-TMLE) to the estimation of pathwise differentiable parameters in semi-parametric models. The procedure creates a sequence of candidate targeted maximum likelihood estimators based on an initial estimate for Q coupled with a succession of increasingly non-parametric estimates for g. In a departure from current state of the art nuisance parameter estimation, C-TMLE estimates of g are constructed based on a loss function for the targeted maximum likelihood estimator of the relevant factor Q that uses the nuisance parameter to carry out the fluctuation, instead of a loss function for the nuisance parameter itself. Likelihood-based cross-validation is used to select the best estimator among all candidate TMLE estimators of Q0 in this sequence. A penalized-likelihood loss function for Q is suggested when the parameter of interest is borderline-identifiable. We present theoretical results for “collaborative double robustness,” demonstrating that the collaborative targeted maximum

  6. The Relative Performance of Targeted Maximum Likelihood Estimators

    PubMed Central

    Porter, Kristin E.; Gruber, Susan; van der Laan, Mark J.; Sekhon, Jasjeet S.

    2011-01-01

    There is an active debate in the literature on censored data about the relative performance of model based maximum likelihood estimators, IPCW-estimators, and a variety of double robust semiparametric efficient estimators. Kang and Schafer (2007) demonstrate the fragility of double robust and IPCW-estimators in a simulation study with positivity violations. They focus on a simple missing data problem with covariates where one desires to estimate the mean of an outcome that is subject to missingness. Responses by Robins, et al. (2007), Tsiatis and Davidian (2007), Tan (2007) and Ridgeway and McCaffrey (2007) further explore the challenges faced by double robust estimators and offer suggestions for improving their stability. In this article, we join the debate by presenting targeted maximum likelihood estimators (TMLEs). We demonstrate that TMLEs that guarantee that the parametric submodel employed by the TMLE procedure respects the global bounds on the continuous outcomes, are especially suitable for dealing with positivity violations because in addition to being double robust and semiparametric efficient, they are substitution estimators. We demonstrate the practical performance of TMLEs relative to other estimators in the simulations designed by Kang and Schafer (2007) and in modified simulations with even greater estimation challenges. PMID:21931570

  7. Optical Absorption in Liquid Semiconductors

    NASA Astrophysics Data System (ADS)

    Bell, Florian Gene

    An infrared absorption cell has been developed which is suitable for high temperature liquids which have absorptions in the range .1-10('3) cm('-1). The cell is constructed by clamping a gasket between two flat optical windows. This unique design allows the use of any optical windows chemically compatible with the liquid. The long -wavelength limit of the measurements is therefore limited only by the choice of the optical windows. The thickness of the cell can easily be set during assembly, and can be varied from 50 (mu)m to .5 cm. Measurements of the optical absorption edge were performed on the liquid alloy Se(,1-x)Tl(,x) for x = 0, .001, .002, .003, .005, .007, and .009, from the melting point up to 475(DEGREES)C. The absorption was found to be exponential in the photon energy over the experimental range from 0.3 eV to 1.2 eV. The absorption increased linearly with concentration according to the empirical relation (alpha)(,T)(h(nu)) = (alpha)(,1) + (alpha)(,2)x, and the absorption (alpha)(,1) was interpreted as the absorption in the absence of T1. (alpha)(,1) also agreed with the measured absorption in 100% Se at corresponding temperatures and energies. The excess absorption defined by (DELTA)(alpha) = (alpha)(,T)(h(nu))-(alpha)(,1) was interpreted as the absorption associated with Tl and was found to be thermally activated with an activation energy E(,t) = 0.5 eV. The exponential edge is explained as absorption on atoms immersed in strong electric fields surrounding ions. The strong fields give rise to an absorption tail similar to the Franz-Keldysh effect. A simple calculation is performed which is based on the Dow-Redfield theory of absorption in an electric field with excitonic effects included. The excess absorption at low photon energies is proportional to the square of the concentration of ions, which are proposed to exist in the liquid according to the relation C(,i) (PROPORTIONAL) x(' 1/2)(.)e('-E)t('/kT), which is the origin of the thermal activation

  8. X-ray Absorption Spectroscopy

    SciTech Connect

    Yano, Junko; Yachandra, Vittal K.

    2009-07-09

    This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

  9. Positional information, in bits

    PubMed Central

    Dubuis, Julien O.; Tkačik, Gašper; Wieschaus, Eric F.; Gregor, Thomas; Bialek, William

    2013-01-01

    Cells in a developing embryo have no direct way of “measuring” their physical position. Through a variety of processes, however, the expression levels of multiple genes come to be correlated with position, and these expression levels thus form a code for “positional information.” We show how to measure this information, in bits, using the gap genes in the Drosophila embryo as an example. Individual genes carry nearly two bits of information, twice as much as would be expected if the expression patterns consisted only of on/off domains separated by sharp boundaries. Taken together, four gap genes carry enough information to define a cell’s location with an error bar of along the anterior/posterior axis of the embryo. This precision is nearly enough for each cell to have a unique identity, which is the maximum information the system can use, and is nearly constant along the length of the embryo. We argue that this constancy is a signature of optimality in the transmission of information from primary morphogen inputs to the output of the gap gene network. PMID:24089448

  10. o-nitrobenzyl photolabile protecting groups with red-shifted absorption: syntheses and uncaging cross-sections for one- and two-photon excitation.

    PubMed

    Aujard, Isabelle; Benbrahim, Chouaha; Gouget, Marine; Ruel, Odile; Baudin, Jean-Bernard; Neveu, Pierre; Jullien, Ludovic

    2006-09-01

    We evaluated the o-nitrobenzyl platform for designing photolabile protecting groups with red-shifted absorption that could be photolyzed upon one- and two-photon excitation. Several synthetic pathways to build different conjugated o-nitrobenzyl backbones, as well as to vary the benzylic position, are reported. Relative to the reference 4,5-dimethoxy-2-nitrobenzyl group, several o-nitrobenzyl derivatives exhibit a large and red-shifted one-photon absorption within the near-UV range. Uncaging after one-photon excitation was studied by measuring UV-visible absorption and steady-state fluorescence emission on model caged ethers and esters. In the whole series investigated, the caged substrates were released cleanly upon photolysis. Quantum yields of uncaging after one-photon absorption lie within the 0.1-1 % range. We observed that these drop as the maximum wavelength absorption of the o-nitrobenzyl protecting group is increased. A new method based on fluorescence correlation spectroscopy (FCS) after two-photon excitation was used to measure the action uncaging cross section for two-photon excitation. The series of o-nitrobenzyl caged fluorescent coumarins investigated exhibit values within the 0.1-0.01 Goeppert-Mayer (GM) range. Such results are in line with the low quantum yields of uncaging associated with cross-sections of 1-50 GM for two-photon absorption. Although the cross-sections for one- and two-photon absorption of o-nitrobenzyl photolabile protecting groups can be readily improved, we emphasize the difficulty in enlarging the corresponding action uncaging cross-sections in view of the observed trend of their quantum yield of uncaging. PMID:16763952

  11. Absorption of Thermal Neutrons in Uranium

    DOE R&D Accomplishments Database

    Creutz, E. C.; Wilson, R. R.; Wigner, E. P.

    1941-09-26

    A knowledge of the absorption processes for neutrons in uranium is important for planning a chain reaction experiment. The absorption of thermal neutrons in uranium and uranium oxide has been studied. Neutrons from the cyclotron were slowed down by passage through a graphite block. A uranium or uranium oxide sphere was placed at various positions in the block. The neutron intensity at different points in the sphere and in the graphite was measured by observing the activity induced in detectors or uranium oxide or manganese. It was found that both the fission activity in the uranium oxide and the activity induced in manganese was affected by non-thermal neutrons. An experimental correction for such effects was made by making measurements with the detectors surrounded by cadmium. After such corrections the results from three methods of procedure with the uranium oxide detectors and from the manganese detectors were consistent to within a few per cent.

  12. Ultraviolet absorption spectrum of chlorine nitrite, ClONO

    NASA Technical Reports Server (NTRS)

    Molina, L. T.; Molina, M. J.

    1977-01-01

    The near-ultraviolet absorption spectrum of chlorine nitrite (ClONO) has been quantitatively investigated over the wavelength range 230-400 nm at 231 K. An absorption maximum was observed at 290 nm with a cross section of 1.5 by 10 to the -18th power sq cm. The calculated lifetime against photodissociation for ClONO in the atmosphere is 2 to 3 minutes. The large photolysis rate indicates that ClONO does not play a significant role in the stratosphere as a temporary holding tank for chlorine.

  13. Thickness Optimization for Petroleum Coke in Microwave Dehydrating Based on the Analysis of Dynamic Absorption Efficiency

    NASA Astrophysics Data System (ADS)

    Shang, Xiaobiao; Chen, Junruo; Peng, Jinhui; Chen, Hua; Zhang, Weifeng; Guo, Shenghui; Chen, Guo

    2015-07-01

    An analytical approach is proposed to optimize the thickness of petroleum coke for achieving maximum microwave power absorption in microwave heating based on analysis of reflection loss (RL). The microwave RL of the petroleum coke layer was studied over the moisture content range of 1%-5% at 20 °C and the petroleum coke (10% moisture content) in the temperature range of 20 to 100 °C at 2.45 GHz. The results show that RL depends sensitively on the thickness of the petroleum coke and the absorption peak shifts towards a larger thickness as the moisture content of the petroleum coke increases. There exists a matching thickness corresponding to the maximum microwave absorption, the maximum absorbing peak decreases when the thickness of petroleum coke exceeds the matching thickness. We also show that the absorption peak is found to move towards a smaller thickness region with increasing petroleum coke temperature.

  14. Saturnian trapped radiation and its absorption by satellites and rings: the first results from Pioneer 11

    SciTech Connect

    Simpson, J.A.; Bastian, T.S.; Chenette, D.L.; Lentz, G.A.; McKibben, R.B.; Pyle, K.R.; Tuzzolino, A.J.

    1980-01-25

    Electrons and protons accelerated and trapped in a Saturnian magnetic field were found by the University of Chicago experiments on Pioneer 11 within 20 Saturn radii (R/sub S/) of the planet. In the innermost regions, strong absorption effects due to satellites and ring material were observed, and from approx.4 R/sub S/ inwards to the outer edge of the A ring at 2.30 R/sub S/ (where the radiation is absorbed), the intensity distributions of protons (greater than or equal to 0.5 million electron volts) and electrons (2 to 20 million electron volts) were axially symmetric, consistent with a centered dipole aligned with the planetary rotation axis. The maximum fluxes observed for protons (> 35 million electron volts and for electrons > 3.4 million electron volts) were 3 x 10/sup 4/ and 3 x 10/sup 6/ per square centimeter per second, respectively. Absorption of radiation by Mimas provides a means of estimating the radial diffusion coefficient for charged particle transport. However, the rapid flux increases observed between absorption features raise new questions concerning the physics of charged-particle transport and acceleration. An absorption feature 2.5 R/sub S/ has led to the discovery of a previously unknown satellite with a diameter of greater than or equal to 200 kilometers, semimajor axis of 2.51 R/sub S/, and eccentricity of 0.013. Radiation absorption features that suggest a nonuniform distribution of matter around Saturn have also been found from 2.34 to 2.36 R/sub S/, near the position of the F ring discovered by the Pioneer imaging experiment. Beneath the A, B, and C rings a low flux of high-energy electrons was observed. It is concluded that the inner Saturn magnetosphere, because of its near-axial symmetry and the many discrete radiation absorption regions, offers a unique opportunity to study the acceleration and transport of charged particles in a planetary magnetic field. 5 figures, 2 tables

  15. Middle Holocene thermal maximum in eastern Beringia

    NASA Astrophysics Data System (ADS)

    Kaufman, D. S.; Bartlein, P. J.

    2015-12-01

    A new systematic review of diverse Holocene paleoenvironmental records (Kaufman et al., Quat. Sci. Rev., in revision) has clarified the primary multi-centennial- to millennial-scale trends across eastern Beringia (Alaska, westernmost Canada and adjacent seas). Composite time series from midges, pollen, and biogeochemical indicators are compared with new summaries of mountain-glacier and lake-level fluctuations, terrestrial water-isotope records, sea-ice and sea-surface-temperature analyses, and peatland and thaw-lake initiation frequencies. The paleo observations are also compared with recently published simulations (Bartlein et al., Clim. Past Discuss., 2015) that used a regional climate model to simulate the effects of global and regional-scale forcings at 11 and 6 ka. During the early Holocene (11.5-8 ka), rather than a prominent thermal maximum as suggested previously, the newly compiled paleo evidence (mostly sensitive to summer conditions) indicates that temperatures were highly variable, at times both higher and lower than present, although the overall lowest average temperatures occurred during the earliest Holocene. During the middle Holocene (8-4 ka), glaciers retreated as the regional average temperature increased to a maximum between 7 and 5 ka, as reflected in most proxy types. The paleo evidence for low and variable temperatures during the early Holocene contrasts with more uniformly high temperatures during the middle Holocene and agrees with the climate simulations, which show that temperature in eastern Beringia was on average lower at 11 ka and higher at 6 ka than at present (pre-industrial). Low temperatures during the early Holocene can be attributed in part to the summer chilling caused by flooding the continental shelves, whereas the mid-Holocene thermal maximum was likely driven by the loss of the Laurentide ice sheet, rise in greenhouse gases, higher-than-present summer insolation, and expansion of forest over tundra.

  16. Maximum caliber inference of nonequilibrium processes.

    PubMed

    Otten, Moritz; Stock, Gerhard

    2010-07-21

    Thirty years ago, Jaynes suggested a general theoretical approach to nonequilibrium statistical mechanics, called maximum caliber (MaxCal) [Annu. Rev. Phys. Chem. 31, 579 (1980)]. MaxCal is a variational principle for dynamics in the same spirit that maximum entropy is a variational principle for equilibrium statistical mechanics. Motivated by the success of maximum entropy inference methods for equilibrium problems, in this work the MaxCal formulation is applied to the inference of nonequilibrium processes. That is, given some time-dependent observables of a dynamical process, one constructs a model that reproduces these input data and moreover, predicts the underlying dynamics of the system. For example, the observables could be some time-resolved measurements of the folding of a protein, which are described by a few-state model of the free energy landscape of the system. MaxCal then calculates the probabilities of an ensemble of trajectories such that on average the data are reproduced. From this probability distribution, any dynamical quantity of the system can be calculated, including population probabilities, fluxes, or waiting time distributions. After briefly reviewing the formalism, the practical numerical implementation of MaxCal in the case of an inference problem is discussed. Adopting various few-state models of increasing complexity, it is demonstrated that the MaxCal principle indeed works as a practical method of inference: The scheme is fairly robust and yields correct results as long as the input data are sufficient. As the method is unbiased and general, it can deal with any kind of time dependency such as oscillatory transients and multitime decays. PMID:20649320

  17. Gastrointestinal absorption and biological activities of serine and cysteine proteases of animal and plant origin: review on absorption of serine and cysteine proteases

    PubMed Central

    Lorkowski, Gerhard

    2012-01-01

    Research has confirmed that peptides and larger protein molecules pass through the mucosal barrier of the gastrointestinal tract. Orally administered serine and cysteine proteases of plant and animal origin also reach blood and lymph as intact, high molecular weight and physiologically active protein molecules. Their absorption may be supported by a self-enhanced paracellular transport mechanism resulting in sub-nanomolar concentration of transiently free protease molecules or, in a complex with anti-proteases, at higher concentrations. Data from pharmacokinetic investigations reveals dose linearity for maximum plasma levels of free proteases not unusual for body proteases and a high inter-individual variability. There is no interference with each other after oral administration of protease combinations, and absorption follows an unusual invasion and elimination kinetic due to slow velocity of absorption and a fast 100% protein binding to anti-proteases. Oral application of proteases leads to increased proteolytic serum activity and increased plasma concentrations of the corresponding anti-proteases. Their biological activity is determined by their proteolytic activity as free proteases on soluble peptides/proteins or cell surface receptors (e.g. protease activated receptors) and their activity in the complex formed with their specific and/or unspecific anti-proteases. The anti-protease-complexes, during immune reaction and injuries often loaded with different cytokines, are cleared from body fluids and tissue by receptor mediated endocytosis on hepatocytes and/or blood cells. Oral administration of enteric coated tablets containing proteolytic enzymes of plant and animal origin may be a safe method to stabilize, positively influence or enhance physiological and immunological processes during disease processes and in healthy consumers. PMID:22461953

  18. Maximum aposteriori joint source/channel coding

    NASA Technical Reports Server (NTRS)

    Sayood, Khalid; Gibson, Jerry D.

    1991-01-01

    A maximum aposteriori probability (MAP) approach to joint source/channel coder design is presented in this paper. This method attempts to explore a technique for designing joint source/channel codes, rather than ways of distributing bits between source coders and channel coders. For a nonideal source coder, MAP arguments are used to design a decoder which takes advantage of redundancy in the source coder output to perform error correction. Once the decoder is obtained, it is analyzed with the purpose of obtaining 'desirable properties' of the channel input sequence for improving overall system performance. Finally, an encoder design which incorporates these properties is proposed.

  19. Design of toroidal transformers for maximum efficiency

    NASA Technical Reports Server (NTRS)

    Dayton, J. A., Jr.

    1972-01-01

    The design of the most efficient toroidal transformer that can be built given the frequency, volt-ampere rating, magnetic flux density, window fill factor, and materials is described. With the above all held constant and only the dimensions of the magnetic core varied, the most efficient design occurs when the copper losses equal 60 percent of the iron losses. When this criterion is followed, efficiency is only slightly dependent on design frequency and fill factor. The ratios of inside diameter to outside diameter and height to build of the magnetic core that result in transformers of maximum efficiency are computed.

  20. Multiperiod Maximum Loss is time unit invariant.

    PubMed

    Kovacevic, Raimund M; Breuer, Thomas

    2016-01-01

    Time unit invariance is introduced as an additional requirement for multiperiod risk measures: for a constant portfolio under an i.i.d. risk factor process, the multiperiod risk should equal the one period risk of the aggregated loss, for an appropriate choice of parameters and independent of the portfolio and its distribution. Multiperiod Maximum Loss over a sequence of Kullback-Leibler balls is time unit invariant. This is also the case for the entropic risk measure. On the other hand, multiperiod Value at Risk and multiperiod Expected Shortfall are not time unit invariant. PMID:27563531

  1. Dynamical maximum entropy approach to flocking

    NASA Astrophysics Data System (ADS)

    Cavagna, Andrea; Giardina, Irene; Ginelli, Francesco; Mora, Thierry; Piovani, Duccio; Tavarone, Raffaele; Walczak, Aleksandra M.

    2014-04-01

    We derive a new method to infer from data the out-of-equilibrium alignment dynamics of collectively moving animal groups, by considering the maximum entropy model distribution consistent with temporal and spatial correlations of flight direction. When bird neighborhoods evolve rapidly, this dynamical inference correctly learns the parameters of the model, while a static one relying only on the spatial correlations fails. When neighbors change slowly and the detailed balance is satisfied, we recover the static procedure. We demonstrate the validity of the method on simulated data. The approach is applicable to other systems of active matter.

  2. Maximum a posteriori decoder for digital communications

    NASA Technical Reports Server (NTRS)

    Altes, Richard A. (Inventor)

    1997-01-01

    A system and method for decoding by identification of the most likely phase coded signal corresponding to received data. The present invention has particular application to communication with signals that experience spurious random phase perturbations. The generalized estimator-correlator uses a maximum a posteriori (MAP) estimator to generate phase estimates for correlation with incoming data samples and for correlation with mean phases indicative of unique hypothesized signals. The result is a MAP likelihood statistic for each hypothesized transmission, wherein the highest value statistic identifies the transmitted signal.

  3. Conductivity maximum in a charged colloidal suspension

    SciTech Connect

    Bastea, S

    2009-01-27

    Molecular dynamics simulations of a charged colloidal suspension in the salt-free regime show that the system exhibits an electrical conductivity maximum as a function of colloid charge. We attribute this behavior to two main competing effects: colloid effective charge saturation due to counterion 'condensation' and diffusion slowdown due to the relaxation effect. In agreement with previous observations, we also find that the effective transported charge is larger than the one determined by the Stern layer and suggest that it corresponds to the boundary fluid layer at the surface of the colloidal particles.

  4. Efficient maximum entropy algorithms for electronic structure

    SciTech Connect

    Silver, R.N.; Roeder, H.; Voter, A.F.; Kress, J.D.

    1996-04-01

    Two Chebyshev recursion methods are presented for calculations with very large sparse Hamiltonians, the kernel polynomial method (KPM) and the maximum entropy method (MEM). If limited statistical accuracy and energy resolution are acceptable, they provide linear scaling methods for the calculation of physical properties involving large numbers of eigenstates such as densities of states, spectral functions, thermodynamics, total energies for Monte Carlo simulations and forces for molecular dynamics. KPM provides a uniform approximation to a DOS, with resolution inversely proportional to the number of Chebyshev moments, while MEM can achieve significantly higher, but non-uniform, resolution at the risk of possible artifacts. This paper emphasizes efficient algorithms.

  5. Metallic positive expulsion diaphragms

    NASA Technical Reports Server (NTRS)

    Gleich, D.

    1972-01-01

    High-cycle life ring-reinforced hemispherical type positive expulsion diaphragm performance was demonstrated by room temperature fluid expulsion tests of 13" diameter, 8 mil thick stainless steel configurations. A maximum of eleven (11) leak-free, fluid expulsions were achieved by a 25 deg cone angle diaphragm hoop-reinforced with .110-inch cross-sectional diameter wires. This represents a 70% improvement in diaphragm reversal cycle life compared to results previously obtained. The reversal tests confirmed analytic predictions for diaphragm cycle life increases due to increasing values of diaphragm cone angle, radius to thickness ratio and material strain to necking capacity. Practical fabrication techniques were demonstrated for forming close-tolerance, thin corrugated shells and for obtaining closely controlled reinforcing ring stiffness required to maximize diaphragm cycle life. A non-destructive inspection technique for monitoring large local shell bending strains was developed.

  6. An Improved Maximum Neural Network with Stochastic Dynamics Characteristic for Maximum Clique Problem

    NASA Astrophysics Data System (ADS)

    Yang, Gang; Tang, Zheng; Dai, Hongwei

    Through analyzing the dynamics characteristic of maximum neural network with an added vertex, we find that the solution quality is mainly determined by the added vertex weights. In order to increase maximum neural network ability, a stochastic nonlinear self-feedback and flexible annealing strategy are embedded in maximum neural network, which makes the network more powerful to escape local minima and be independent of the initial values. Simultaneously, we present that solving ability of maximum neural network is dependence on problem. We introduce a new parameter into our network to improve the solving ability. The simulation in k random graph and some DIMACS clique instances in the second DIMACS challenge shows that our improved network is superior to other algorithms in light of the solution quality and CPU time.

  7. Intestinal folate absorption

    PubMed Central

    Strum, Williamson; Nixon, Peter F.; Bertino, Joseph B.; Binder, Henry J.

    1971-01-01

    Intestinal absorption of the monoglutamate form of the principal dietary and circulating folate compound, 5-methyltetrahydrofolic acid (5-MTHF), was studied in the rat utilizing a synthetic highly purified radiolabeled diastereoisomer. Chromatography confirmed that the compound was not altered after transfer from the mucosa to the serosa. Accumulation against a concentration gradient was not observed in duodenal, jejunal, or ileal segments at 5-MTHF concentration from 0.5 to 500 nmoles/liter. Unidirectional transmural flux determination also did not indicate a significant net flux. Mucosal to serosal transfer of 5-MTHF was similar in all segments of the intestine and increased in a linear fashion with increased initial mucosal concentrations. Further, no alteration in 5-MTHF transfer was found when studied in the presence of metabolic inhibitors or folate compounds. These results indicate that 5-MTHF is not absorbed by the rat small intestine by a carrier-mediated system and suggest that 5-MTHF transfer most likely represents diffusion. Images PMID:5564397

  8. Maximum likelihood decoding of Reed Solomon Codes

    SciTech Connect

    Sudan, M.

    1996-12-31

    We present a randomized algorithm which takes as input n distinct points ((x{sub i}, y{sub i})){sup n}{sub i=1} from F x F (where F is a field) and integer parameters t and d and returns a list of all univariate polynomials f over F in the variable x of degree at most d which agree with the given set of points in at least t places (i.e., y{sub i} = f (x{sub i}) for at least t values of i), provided t = {Omega}({radical}nd). The running time is bounded by a polynomial in n. This immediately provides a maximum likelihood decoding algorithm for Reed Solomon Codes, which works in a setting with a larger number of errors than any previously known algorithm. To the best of our knowledge, this is the first efficient (i.e., polynomial time bounded) algorithm which provides some maximum likelihood decoding for any efficient (i.e., constant or even polynomial rate) code.

  9. States of Maximum Thermodynamic Efficiency In Daisyworld

    NASA Astrophysics Data System (ADS)

    Pujol, T.

    Daisyworld is the simplest example used to illustrate the implications of the Gaia hypothesis. The interaction between the environment and the biota follows from the assumption of using daisies with different colours (i.e., albedos) than that of the bare earth. Then, the amount of daisies may modify the energy absorbed by the planet. In the classical version of Daisyworld, turbulent fluxes adopt a diffusive approximation, which clearly constraints the range of values for the solar insolation from which biota may grow in the planet. Here we apply the maximum entropy principle (MEP) to Daisyworld. We conclude that the MEP sets the maximum range of values for the solar insolation with a non-zero amount of daisies. Outside this range, daisies cannot grow in the planet for any physically realistic heat flux. Inside this range, the distribution of daisies is set to agree with the MEP. The range of values for the solar insolation from which biota stabilises the climate is substantially enlarged in comparison with the classical version of Daisyworld.

  10. Solar Absorption in Cloudy Atmospheres

    NASA Technical Reports Server (NTRS)

    Harshvardhan; Ridgway, William; Ramaswamy, V.; Freidenreich, S. M.; Batey, Michael

    1996-01-01

    The theoretical computations used to compute spectral absorption of solar radiation are discussed. Radiative properties relevant to the cloud absorption problem are presented and placed in the context of radiative forcing. Implications for future measuring programs and the effect of horizontal inhomogeneities are discussed.

  11. Atlas of Infrared Absorption Lines

    NASA Technical Reports Server (NTRS)

    Park, J. H.

    1977-01-01

    This atlas of infrared absorption line contains absorption line parameters (line strength vs. wavenumber) from 500 to 7000 cm(exp-1) for 15 gases: H2O, CO2, O3, N2O, CO, CH4, O2, SO2, NO, NO2, NH3, HCl, HF, HNO3 and CH3Cl.

  12. Hot tube atomic absorption spectrochemistry.

    PubMed

    Woodriff, R; Stone, R W

    1968-07-01

    A small, commercially available atomic absorption instrument is used with a heated graphite tube for the atomic absorption analysis of liquid and solid silver samples. Operating conditions of the furnace are described and a sensitivity of about 5 ng of silver is reported. PMID:20068797

  13. Subgap Absorption in Conjugated Polymers

    DOE R&D Accomplishments Database

    Sinclair, M.; Seager, C. H.; McBranch, D.; Heeger, A. J; Baker, G. L.

    1991-01-01

    Along with X{sup (3)}, the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter which will ultimately determine the utility of conjugated polymers in active integrated optical devices. With an absorptance sensitivity of < 10{sup {minus}5}, Photothermal Deflection Spectroscopy (PDS) is ideal for determining the absorption coefficients of thin films of transparent'' materials. We have used PDS to measure the optical absorption spectra of the conjugated polymers poly(1,4-phenylene-vinylene) (and derivitives) and polydiacetylene-4BCMU in the spectral region from 0.55 eV to 3 eV. Our spectra show that the shape of the absorption edge varies considerably from polymer to polymer, with polydiacetylene-4BCMU having the steepest absorption edge. The minimum absorption coefficients measured varied somewhat with sample age and quality, but were typically in the range 1 cm{sup {minus}1} to 10 cm{sup {minus}1}. In the region below 1 eV, overtones of C-H stretching modes were observed, indicating that further improvements in transparency in this spectral region might be achieved via deuteration of fluorination.

  14. Atmospheric absorption of sound - Update

    NASA Technical Reports Server (NTRS)

    Bass, H. E.; Sutherland, L. C.; Zuckerwar, A. J.

    1990-01-01

    Best current expressions for the vibrational relaxation times of oxygen and nitrogen in the atmosphere are used to compute total absorption. The resulting graphs of total absorption as a function of frequency for different humidities should be used in lieu of the graph published earlier by Evans et al (1972).

  15. Optical absorption of silicon nanowires

    SciTech Connect

    Xu, T.; Lambert, Y.; Krzeminski, C.; Grandidier, B.; Stievenard, D.; Leveque, G.; Akjouj, A.; Pennec, Y.; Djafari-Rouhani, B.

    2012-08-01

    We report on simulations and measurements of the optical absorption of silicon nanowires (NWs) versus their diameter. We first address the simulation of the optical absorption based on two different theoretical methods: the first one, based on the Green function formalism, is useful to calculate the scattering and absorption properties of a single or a finite set of NWs. The second one, based on the finite difference time domain (FDTD) method, is well-adapted to deal with a periodic set of NWs. In both cases, an increase of the onset energy for the absorption is found with increasing diameter. Such effect is experimentally illustrated, when photoconductivity measurements are performed on single tapered Si nanowires connected between a set of several electrodes. An increase of the nanowire diameter reveals a spectral shift of the photocurrent intensity peak towards lower photon energies that allow to tune the absorption onset from the ultraviolet radiations to the visible light spectrum.

  16. 14 CFR 23.1524 - Maximum passenger seating configuration.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Maximum passenger seating configuration. 23... Operating Limitations and Information § 23.1524 Maximum passenger seating configuration. The maximum passenger seating configuration must be established....

  17. 14 CFR 23.1524 - Maximum passenger seating configuration.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maximum passenger seating configuration. 23... Operating Limitations and Information § 23.1524 Maximum passenger seating configuration. The maximum passenger seating configuration must be established....

  18. 14 CFR 23.1524 - Maximum passenger seating configuration.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Maximum passenger seating configuration. 23... Operating Limitations and Information § 23.1524 Maximum passenger seating configuration. The maximum passenger seating configuration must be established....

  19. 14 CFR 23.1524 - Maximum passenger seating configuration.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maximum passenger seating configuration. 23... Operating Limitations and Information § 23.1524 Maximum passenger seating configuration. The maximum passenger seating configuration must be established....

  20. 14 CFR 23.1524 - Maximum passenger seating configuration.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Maximum passenger seating configuration. 23... Operating Limitations and Information § 23.1524 Maximum passenger seating configuration. The maximum passenger seating configuration must be established....

  1. Gas-absorption process

    DOEpatents

    Stephenson, Michael J.; Eby, Robert S.

    1978-01-01

    This invention is an improved gas-absorption process for the recovery of a desired component from a feed-gas mixture containing the same. In the preferred form of the invention, the process operations are conducted in a closed-loop system including a gas-liquid contacting column having upper, intermediate, and lower contacting zones. A liquid absorbent for the desired component is circulated through the loop, being passed downwardly through the column, regenerated, withdrawn from a reboiler, and then recycled to the column. A novel technique is employed to concentrate the desired component in a narrow section of the intermediate zone. This technique comprises maintaining the temperature of the liquid-phase input to the intermediate zone at a sufficiently lower value than that of the gas-phase input to the zone to effect condensation of a major part of the absorbent-vapor upflow to the section. This establishes a steep temperature gradient in the section. The stripping factors below this section are selected to ensure that virtually all of the gases in the downflowing absorbent from the section are desorbed. The stripping factors above the section are selected to ensure re-dissolution of the desired component but not the less-soluble diluent gases. As a result, a peak concentration of the desired component is established in the section, and gas rich in that component can be withdrawn therefrom. The new process provides important advantages. The chief advantage is that the process operations can be conducted in a single column in which the contacting zones operate at essentially the same pressure.

  2. Hydraulic Limits on Maximum Plant Transpiration

    NASA Astrophysics Data System (ADS)

    Manzoni, S.; Vico, G.; Katul, G. G.; Palmroth, S.; Jackson, R. B.; Porporato, A. M.

    2011-12-01

    Photosynthesis occurs at the expense of water losses through transpiration. As a consequence of this basic carbon-water interaction at the leaf level, plant growth and ecosystem carbon exchanges are tightly coupled to transpiration. In this contribution, the hydraulic constraints that limit transpiration rates under well-watered conditions are examined across plant functional types and climates. The potential water flow through plants is proportional to both xylem hydraulic conductivity (which depends on plant carbon economy) and the difference in water potential between the soil and the atmosphere (the driving force that pulls water from the soil). Differently from previous works, we study how this potential flux changes with the amplitude of the driving force (i.e., we focus on xylem properties and not on stomatal regulation). Xylem hydraulic conductivity decreases as the driving force increases due to cavitation of the tissues. As a result of this negative feedback, more negative leaf (and xylem) water potentials would provide a stronger driving force for water transport, while at the same time limiting xylem hydraulic conductivity due to cavitation. Here, the leaf water potential value that allows an optimum balance between driving force and xylem conductivity is quantified, thus defining the maximum transpiration rate that can be sustained by the soil-to-leaf hydraulic system. To apply the proposed framework at the global scale, a novel database of xylem conductivity and cavitation vulnerability across plant types and biomes is developed. Conductivity and water potential at 50% cavitation are shown to be complementary (in particular between angiosperms and conifers), suggesting a tradeoff between transport efficiency and hydraulic safety. Plants from warmer and drier biomes tend to achieve larger maximum transpiration than plants growing in environments with lower atmospheric water demand. The predicted maximum transpiration and the corresponding leaf water

  3. Distributed Bragg Reflectors With Reduced Optical Absorption

    DOEpatents

    Klem, John F.

    2005-08-16

    A new class of distributed Bragg reflectors has been developed. These distributed Bragg reflectors comprise interlayers positioned between sets of high-index and low-index quarter-wave plates. The presence of these interlayers is to reduce photon absorption resulting from spatially indirect photon-assisted electronic transitions between the high-index and low-index quarter wave plates. The distributed Bragg reflectors have applications for use in vertical-cavity surface-emitting lasers for use at 1.55 .mu.m and at other wavelengths of interest.

  4. Approximate maximum likelihood decoding of block codes

    NASA Technical Reports Server (NTRS)

    Greenberger, H. J.

    1979-01-01

    Approximate maximum likelihood decoding algorithms, based upon selecting a small set of candidate code words with the aid of the estimated probability of error of each received symbol, can give performance close to optimum with a reasonable amount of computation. By combining the best features of various algorithms and taking care to perform each step as efficiently as possible, a decoding scheme was developed which can decode codes which have better performance than those presently in use and yet not require an unreasonable amount of computation. The discussion of the details and tradeoffs of presently known efficient optimum and near optimum decoding algorithms leads, naturally, to the one which embodies the best features of all of them.

  5. Lead in soil: Recommended maximum permissible levels

    SciTech Connect

    Madhavan, S.; Rosenman, K.D.; Shehata, T.

    1989-06-01

    Lead in soil has been recognized as a public health problem, particularly among children. In recent years, attention has been directed to cumulative adverse effects of lead at low levels of intake. Lead-contaminated soil and dust have been identified as important contributors to blood lead levels. Based on available data on blood lead and lead in soil, an approach has been developed to suggest a permissible level of lead in soil, below which there will be reasonable certainty that adverse health effects will not occur. An acceptable level of 600 ppm of lead in soil suggested as a ''safe'' level would contribute no more than 5 micrograms/dl to total blood lead of children under 12 years of age. Maximum permissible levels of lead in soil have been recommended based on the dose-response relationship of lead in soil and blood lead in children.

  6. Experimental shock metamorphism of maximum microcline

    NASA Technical Reports Server (NTRS)

    Robertson, P. B.

    1975-01-01

    A series of recovery experiments are conducted to study the behavior of single-crystal perthitic maximum microcline shock-loaded to a peak pressure of 417 kbar. Microcline is found to deform in a manner similar to quartz and other alkali feldspars. It is observed that shock-induced cleavages occur initially at or slightly below the Hugoniot elastic limit (60-85 kbar), that shock-induced rather than thermal disordering begins above the Hugoniot elastic limit, and that all types of planar elements form parallel to crystallographic planes of low Miller indices. When increasing pressure, it is found that bulk density, refractive indices, and birefringence of the recovered material decrease and approach diaplectic glass values, whereas disappearance and weakening of reflections in Debye-Sherrer patterns are due to disordering of the feldspar lattice.

  7. The 1988 Solar Maximum Mission event list

    NASA Technical Reports Server (NTRS)

    Dennis, B. R.; Licata, J. P.; Tolbert, A. K.

    1992-01-01

    Information on solar burst and transient activity observed by the Solar Maximum Mission (SMM) during 1988 pointed observations is presented. Data from the following SMM experiments are included: (1) gamma ray spectrometer; (2) hard x ray burst spectrometer; (3) flat crystal spectrometers; (4) bent crystal spectrometer; (5) ultraviolet spectrometer polarimeter; and (6) coronagraph/polarimeter. Correlative optical, radio, and Geostationary Operational Environmental Satellite (GOES) x ray data are also presented. Where possible, bursts, or transients observed in the various wavelengths were grouped into discrete flare events identified by unique event numbers. Each event carries a qualifier denoting the quality or completeness of the observation. Spacecraft pointing coordinates and flare site angular displacement values from sun center are also included.

  8. Quantum optimization and maximum clique problems

    NASA Astrophysics Data System (ADS)

    Yatsenko, Vitaliy A.; Pardalos, Panos M.; Chiarini, Bruno H.

    2004-08-01

    This paper describes a new approach to global optimization and control uses geometric methods and modern quantum mathematics. Polynomial extremal problems (PEP) are considered. PEP constitute one of the most important subclasses of nonlinear programming models. Their distinctive feature is that an objective function and constraints can be expressed by polynomial functions in one or several variables. A general approach to optimization based on quantum holonomic computing algorithms and instanton mechanism. An optimization method based on geometric Lie - algebraic structures on Grassmann manifolds and related with Lax type flows is proposed. Making use of the differential geometric techniques it is shown that associated holonomy groups properly realizing quantum computation can be effectively found concerning polynomial problems. Two examples demonstrating calculation aspects of holonomic quantum computer and maximum clique problems in very large graphs, are considered in detail.

  9. The 1980 solar maximum mission event listing

    NASA Technical Reports Server (NTRS)

    Speich, D. M.; Nelson, J. J.; Licata, J. P.; Tolbert, A. K.

    1991-01-01

    Information is contained on solar burst and transient activity observed by the Solar Maximum Mission (SMM) during 1980 pointed observations. Data from the following SMM experiments are included: (1) Gamma Ray Spectrometer, (2) Hard X-Ray Burst Spectrometer, (3) Hard X-Ray Imaging Spectrometer, (4) Flat Crystal Spectrometer, (5) Bent Crystal Spectrometer, (6) Ultraviolet Spectrometer and Polarimeter, and (7) Coronagraph/Polarimeter. Correlative optical, radio, and Geostationary Operational Environmental Satellite (GOES) x ray data are also presented. Where possible, bursts or transients observed in the various wavelengths were grouped into discrete flare events identified by unique event numbers. Each event carries a qualifier denoting the quality or completeness of the observations. Spacecraft pointing coordinates and flare site angular displacement values from Sun center are also included.

  10. Diffusivity Maximum in a Reentrant Nematic Phase

    PubMed Central

    Stieger, Tillmann; Mazza, Marco G.; Schoen, Martin

    2012-01-01

    We report molecular dynamics simulations of confined liquid crystals using the Gay–Berne–Kihara model. Upon isobaric cooling, the standard sequence of isotropic–nematic–smectic A phase transitions is found. Upon further cooling a reentrant nematic phase occurs. We investigate the temperature dependence of the self-diffusion coefficient of the fluid in the nematic, smectic and reentrant nematic phases. We find a maximum in diffusivity upon isobaric cooling. Diffusion increases dramatically in the reentrant phase due to the high orientational molecular order. As the temperature is lowered, the diffusion coefficient follows an Arrhenius behavior. The activation energy of the reentrant phase is found in reasonable agreement with the reported experimental data. We discuss how repulsive interactions may be the underlying mechanism that could explain the occurrence of reentrant nematic behavior for polar and non-polar molecules. PMID:22837730

  11. Diffusivity maximum in a reentrant nematic phase.

    PubMed

    Stieger, Tillmann; Mazza, Marco G; Schoen, Martin

    2012-01-01

    We report molecular dynamics simulations of confined liquid crystals using the Gay-Berne-Kihara model. Upon isobaric cooling, the standard sequence of isotropic-nematic-smectic A phase transitions is found. Upon further cooling a reentrant nematic phase occurs. We investigate the temperature dependence of the self-diffusion coefficient of the fluid in the nematic, smectic and reentrant nematic phases. We find a maximum in diffusivity upon isobaric cooling. Diffusion increases dramatically in the reentrant phase due to the high orientational molecular order. As the temperature is lowered, the diffusion coefficient follows an Arrhenius behavior. The activation energy of the reentrant phase is found in reasonable agreement with the reported experimental data. We discuss how repulsive interactions may be the underlying mechanism that could explain the occurrence of reentrant nematic behavior for polar and non-polar molecules. PMID:22837730

  12. Characterizing Local Optima for Maximum Parsimony.

    PubMed

    Urheim, Ellen; Ford, Eric; St John, Katherine

    2016-05-01

    Finding the best phylogenetic tree under the maximum parsimony optimality criterion is computationally difficult. We quantify the occurrence of such optima for well-behaved sets of data. When nearest neighbor interchange operations are used, multiple local optima can occur even for "perfect" sequence data, which results in hill-climbing searches that never reach a global optimum. In contrast, we show that when neighbors are defined via the subtree prune and regraft metric, there is a single local optimum for perfect sequence data, and thus, every such search finds a global optimum quickly. We further characterize conditions for which sequences simulated under the Cavender-Farris-Neyman and Jukes-Cantor models of evolution yield well-behaved search spaces. PMID:27234257

  13. The 1989 Solar Maximum Mission event list

    NASA Technical Reports Server (NTRS)

    Dennis, B. R.; Licata, J. P.; Tolbert, A. K.

    1992-01-01

    This document contains information on solar burst and transient activity observed by the Solar Maximum Mission (SMM) during 1989 pointed observations. Data from the following SMM experiments are included: (1) Gamma Ray Spectrometer, (2) Hard X-Ray Burst Spectrometer, (3) Flat Crystal Spectrometer, (4) Bent Crystal Spectrometer, (5) Ultraviolet Spectrometer Polarimeter, and (6) Coronagraph/Polarimeter. Correlative optical, radio, and Geostationary Operational Satellite (GOES) X-ray data are also presented. Where possible, bursts or transients observed in the various wavelengths were grouped into discrete flare events identified by unique event numbers. Each event carries a qualifier denoting the quality or completeness of the observations. Spacecraft pointing coordinates and flare site angular displacement values from sun center are also included.

  14. Maximum entropy model for business cycle synchronization

    NASA Astrophysics Data System (ADS)

    Xi, Ning; Muneepeerakul, Rachata; Azaele, Sandro; Wang, Yougui

    2014-11-01

    The global economy is a complex dynamical system, whose cyclical fluctuations can mainly be characterized by simultaneous recessions or expansions of major economies. Thus, the researches on the synchronization phenomenon are key to understanding and controlling the dynamics of the global economy. Based on a pairwise maximum entropy model, we analyze the business cycle synchronization of the G7 economic system. We obtain a pairwise-interaction network, which exhibits certain clustering structure and accounts for 45% of the entire structure of the interactions within the G7 system. We also find that the pairwise interactions become increasingly inadequate in capturing the synchronization as the size of economic system grows. Thus, higher-order interactions must be taken into account when investigating behaviors of large economic systems.

  15. Spacecraft Maximum Allowable Concentrations for Airborne Contaminants

    NASA Technical Reports Server (NTRS)

    James, John T.

    2008-01-01

    The enclosed table lists official spacecraft maximum allowable concentrations (SMACs), which are guideline values set by the NASA/JSC Toxicology Group in cooperation with the National Research Council Committee on Toxicology (NRCCOT). These values should not be used for situations other than human space flight without careful consideration of the criteria used to set each value. The SMACs take into account a number of unique factors such as the effect of space-flight stress on human physiology, the uniform good health of the astronauts, and the absence of pregnant or very young individuals. Documentation of the values is given in a 5 volume series of books entitled "Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants" published by the National Academy Press, Washington, D.C. These books can be viewed electronically at http://books.nap.edu/openbook.php?record_id=9786&page=3. Short-term (1 and 24 hour) SMACs are set to manage accidental releases aboard a spacecraft and permit risk of minor, reversible effects such as mild mucosal irritation. In contrast, the long-term SMACs are set to fully protect healthy crewmembers from adverse effects resulting from continuous exposure to specific air pollutants for up to 1000 days. Crewmembers with allergies or unusual sensitivity to trace pollutants may not be afforded complete protection, even when long-term SMACs are not exceeded. Crewmember exposures involve a mixture of contaminants, each at a specific concentration (C(sub n)). These contaminants could interact to elicit symptoms of toxicity even though individual contaminants do not exceed their respective SMACs. The air quality is considered acceptable when the toxicity index (T(sub grp)) for each toxicological group of compounds is less than 1, where T(sub grp), is calculated as follows: T(sub grp) = C(sub 1)/SMAC(sub 1) + C(sub 2/SMAC(sub 2) + ...+C(sub n)/SMAC(sub n).

  16. Maximum magnitude in the Lower Rhine Graben

    NASA Astrophysics Data System (ADS)

    Vanneste, Kris; Merino, Miguel; Stein, Seth; Vleminckx, Bart; Brooks, Eddie; Camelbeeck, Thierry

    2014-05-01

    Estimating Mmax, the assumed magnitude of the largest future earthquakes expected on a fault or in an area, involves large uncertainties. No theoretical basis exists to infer Mmax because even where we know the long-term rate of motion across a plate boundary fault, or the deformation rate across an intraplate zone, neither predict how strain will be released. As a result, quite different estimates can be made based on the assumptions used. All one can say with certainty is that Mmax is at least as large as the largest earthquake in the available record. However, because catalogs are often short relative to the average recurrence time of large earthquakes, larger earthquakes than anticipated often occur. Estimating Mmax is especially challenging within plates, where deformation rates are poorly constrained, large earthquakes are rarer and variable in space and time, and often occur on previously unrecognized faults. We explore this issue for the Lower Rhine Graben seismic zone where the largest known earthquake, the 1756 Düren earthquake, has magnitude 5.7 and should occur on average about every 400 years. However, paleoseismic studies suggest that earthquakes with magnitudes up to 6.7 occurred during the Late Pleistocene and Holocene. What to assume for Mmax is crucial for critical facilities like nuclear power plants that should be designed to withstand the maximum shaking in 10,000 years. Using the observed earthquake frequency-magnitude data, we generate synthetic earthquake histories, and sample them over shorter intervals corresponding to the real catalog's completeness. The maximum magnitudes appearing most often in the simulations tend to be those of earthquakes with mean recurrence time equal to the catalog length. Because catalogs are often short relative to the average recurrence time of large earthquakes, we expect larger earthquakes than observed to date to occur. In a next step, we will compute hazard maps for different return periods based on the

  17. Performance bound for quantum absorption refrigerators

    NASA Astrophysics Data System (ADS)

    Correa, Luis A.; Palao, José P.; Adesso, Gerardo; Alonso, Daniel

    2013-04-01

    An implementation of quantum absorption chillers with three qubits has been recently proposed that is ideally able to reach the Carnot performance regime. Here we study the working efficiency of such self-contained refrigerators, adopting a consistent treatment of dissipation effects. We demonstrate that the coefficient of performance at maximum cooling power is upper bounded by 3/4 of the Carnot performance. The result is independent of the details of the system and the equilibrium temperatures of the external baths. We provide design prescriptions that saturate the bound in the limit of a large difference between the operating temperatures. Our study suggests that delocalized dissipation, which must be taken into account for a proper modeling of the machine-baths interaction, is a fundamental source of irreversibility which prevents the refrigerator from approaching the Carnot performance arbitrarily closely in practice. The potential role of quantum correlations in the operation of these machines is also investigated.

  18. Gastrointestinal citrate absorption in nephrolithiasis

    NASA Technical Reports Server (NTRS)

    Fegan, J.; Khan, R.; Poindexter, J.; Pak, C. Y.

    1992-01-01

    Gastrointestinal absorption of citrate was measured in stone patients with idiopathic hypocitraturia to determine if citrate malabsorption could account for low urinary citrate. Citrate absorption was measured directly from recovery of orally administered potassium citrate (40 mEq.) in the intestinal lavage fluid, using an intestinal washout technique. In 7 stone patients citrate absorption, serum citrate levels, peak citrate concentration in serum and area under the curve were not significantly different from those of 7 normal subjects. Citrate absorption was rapid and efficient in both groups, with 96 to 98% absorbed within 3 hours. The absorption of citrate was less efficient from a tablet preparation of potassium citrate than from a liquid preparation, probably due to a delayed release of citrate from wax matrix. However, citrate absorption from solid potassium citrate was still high at 91%, compared to 98% for a liquid preparation. Thus, hypocitraturia is unlikely to be due to an impaired gastrointestinal absorption of citrate in stone patients without overt bowel disease.

  19. Maximum speeds and alpha angles of flowing avalanches

    NASA Astrophysics Data System (ADS)

    McClung, David; Gauer, Peter

    2016-04-01

    um/√H0--; um/√S0- are greater than 2.0 and 1.3 respectively. In addition, to: um/√H0--; um/√S0--, we collected 105 companion values of the αangle for runout positions defined by tanα = H0/X0where X0is horizontal reach calculated from start position to stop position of the tip of the avalanches. The αangle is a very simple measure of runout introduced by Scheidegger (1973) for rock avalanches. McClung and Mears (1991) collected αangles from more than 500 paths with maximum runout estimated for return periods on the order of 100 years and the range of values was: 18o ‑ 42owhich is close to that here: (20o ‑ 45o). The results showed that runout increases(α decreases) with maximum speed but there is considerable scatter in the relationship. The Spearman rank correlation is -0.54 (p < 0.005).Rank correlations of α vs. um/√S0-;um/√H0- are - 0.44;.- 0.56 (both with p < 0.005

  20. Absorption behavior of vanadium in Nafion®

    NASA Astrophysics Data System (ADS)

    Cho, Hyun-Seok; Ohashi, Masato; Van Zee, J. W.

    2014-12-01

    The absorption of vanadium to Nafion® was investigated through ex-situ isotherm and conductivity measurements at 23 °C. The data show a maximum loss of ion exchange capacity (IEC) of 30% for all four oxidation states of vanadium. The affinity of vanadium for N115 was measured by back titration and atomic absorption (AA) and characterized by isotherms at 23 °C, and the affinity is highest for the divalent species and lowest for the pentavalent species in the following order: VO2+ (V5+) < VO2+ (V4+) < V3+ < V2+. Steric hindrance from the associated water complex may explain the lower absorption of vanadium compared to alkali metals. The conductivity for the VO2+ (minimum affinity)-exchanged membrane was 2-3× lower than the sodium-exchanged membrane at an approximate RH = 100%.

  1. Methane absorption variations in the spectrum of Pluto

    SciTech Connect

    Buie, M.W.; Fink, U.

    1987-06-01

    The lightcurve phases of 0.18, 0.35, 0.49, and 0.98 covered by 5600-10,500 A absolute spectrophotometry of Pluto during four nights include minimum (0.98) light and one near-maximum (0.49) light. The spectra are noted to exhibit significant methane band absorption depth variations at 6200, 7200, 7900, 8400, 8600, 8900, and 10,000 A, with the minimum absorption occurring at minimum light and thereby indicating a 30-percent change in the methane column abundance in the course of three days. An attempt is made to model this absorption strength variation with rotational phase terms of an isotropic surface distribution of methane frost and a clear layer of CH4 gas. 34 references.

  2. Resonant Absorption of Bessel Beams

    NASA Astrophysics Data System (ADS)

    Fan, J.; Parra, E.; Milchberg, H. M.

    1999-11-01

    We report the first observation of enhanced laser-plasma optical absorption in a subcritical density plasma resulting from spatial resonances, here in the laser breakdown of a gas with a Bessel beam. The enhancement in absorption is directly correlated to enhancements both in confinement of laser radiation to the plasma and in its heating. Under certain conditions, azimuthal asymmetry in the laser beam is essential for efficient gas breakdown. Simulations of this absorption consistently explain the experimental observations. This work is supported by the National Science Foundation (PHY-9515509) and the US Department of Energy (DEF G0297 ER 41039).

  3. Solar absorption cooling plant in Seville

    SciTech Connect

    Bermejo, Pablo; Pino, Francisco Javier; Rosa, Felipe

    2010-08-15

    A solar/gas cooling plant at the Engineering School of Seville (Spain) was tested during the period 2008-2009. The system is composed of a double-effect LiBr + water absorption chiller of 174 kW nominal cooling capacity, powered by: (1) a pressurized hot water flow delivered by mean of a 352 m{sup 2} solar field of a linear concentrating Fresnel collector and (2) a direct-fired natural gas burner. The objective of the project is to indentify design improvements for future plants and to serve as a guideline. We focused our attention on the solar collector size and dirtiness, climatology, piping heat losses, operation control and coupling between solar collector and chiller. The daily average Fresnel collector efficiency was 0.35 with a maximum of 0.4. The absorption chiller operated with a daily average coefficient of performance of 1.1-1.25, where the solar energy represented the 75% of generator's total heat input, and the solar cooling ratio (quotient between useful cooling and insolation incident on the solar field) was 0.44. (author)

  4. LIBOR troubles: Anomalous movements detection based on maximum entropy

    NASA Astrophysics Data System (ADS)

    Bariviera, Aurelio F.; Martín, María T.; Plastino, Angelo; Vampa, Victoria

    2016-05-01

    According to the definition of the London Interbank Offered Rate (LIBOR), contributing banks should give fair estimates of their own borrowing costs in the interbank market. Between 2007 and 2009, several banks made inappropriate submissions of LIBOR, sometimes motivated by profit-seeking from their trading positions. In 2012, several newspapers' articles began to cast doubt on LIBOR integrity, leading surveillance authorities to conduct investigations on banks' behavior. Such procedures resulted in severe fines imposed to involved banks, who recognized their financial inappropriate conduct. In this paper, we uncover such unfair behavior by using a forecasting method based on the Maximum Entropy principle. Our results are robust against changes in parameter settings and could be of great help for market surveillance.

  5. Absorption enhancement and sensing properties of Ag diamond nanoantenna arrays

    NASA Astrophysics Data System (ADS)

    Yuan, Yu-Yang; Yuan, Zong-Heng; Li, Xiao-Nan; Wu, Jun; Zhang, Wen-Tao; Ye, Song

    2015-07-01

    Noble metal nanoantenna could effectively enhance light absorption and increase detection sensitivity. In this paper, we propose a periodic Ag diamond nanoantenna array to increase the absorption of thin-film solar cells and to improve the detection sensitivity via localized surface plasmon resonance. The effect of nanoantenna arrays on the absorption enhancement is theoretically investigated using the finite difference time domain (FDTD) method with manipulating the spectral response by geometrical parameters of nanoantennas. A maximum absorption enhancement factor of 1.51 has been achieved in this study. In addition, the relation between resonant wavelength (intensity reflectivity) and refractive index is discussed in detail. When detecting the environmental index using resonant wavelengths, a maximum detection sensitivity of about 837 nm/RIU (refractive index unit) and a resolution of about 10-3 RIU can be achieved. Moreover, when using the reflectivity, the sensitivity can be as high as 0.93 AU/RIU. Furthermore, we also have theoretically studied the effectiveness of nanoantennas in distinguishing chemical reagents, solution concentrations, and solution allocation ratios by detecting refractive index. From the results presented in this paper, we conclude that this work might be useful for biosensor detection and other types of detections. Project supported by the International Scientific and Technological Cooperation Projects of Guizhou Province, China (Grant No. 20117035) and the Program for Innovative Research Team of Guilin University of Electronic Technology, China (Grant No. IRTGUET).

  6. Sound absorption by subwavelength membrane structures: A geometric perspective

    NASA Astrophysics Data System (ADS)

    Yang, Min; Li, Yong; Meng, Chong; Fu, Caixing; Mei, Jun; Yang, Zhiyu; Sheng, Ping

    2015-12-01

    Decorated membranes comprising a thin layer of elastic film with small rigid platelets fixed on top have been found to be efficient absorbers of low-frequency sound. In this work we consider the problem of sound absorption from a perspective aimed at deriving upper bounds under different scenarios, i.e., whether the sound is incident from one side only or from both sides, and whether there is a reflecting surface on the back side of the membrane. By considering the negligible thickness of the membrane, usually on the order of a fraction of one millimeter, we derive a relation showing that the sum of the incoming sound waves' (complex) pressure amplitudes, averaged over the area of the membrane, must be equal to that of the outgoing waves. By using this relation, and without going to any details of the wave solutions, it is shown that the maximum absorption achievable from one-sided incidence is 50%, while the maximum absorption with a back-reflecting surface can reach 100%. The latter was attained by the hybridized resonances. All the results are shown to be in excellent agreement with the experiments. This generalized perspective, when used together with the Green function's formalism, can be useful in gaining insights into the constraints on what are achievable in scatterings and absorption by thin film structures and delineating them.

  7. Generalized coherent states under deformed quantum mechanics with maximum momentum

    NASA Astrophysics Data System (ADS)

    Ching, Chee Leong; Ng, Wei Khim

    2013-10-01

    Following the Gazeau-Klauder approach, we construct generalized coherent states (GCS) as the quantum simulator to examine the deformed quantum mechanics, which exhibits an intrinsic maximum momentum. We study deformed harmonic oscillators and compute their probability distribution and entropy of states exactly. Also, a particle in an infinite potential box is studied perturbatively. In particular, unlike usual quantum mechanics, the present deformed case increases the entropy of the Planck scale quantum optical system. Furthermore, for simplicity, we obtain the modified uncertainty principle (MUP) with the perturbative treatment up to leading order. MUP turns out to increase generally. However, for certain values of γ (a parameter of GCS), it is possible that the MUP will vanish and hence will exhibit the classical characteristic. This is interpreted as the manifestation of the intrinsic high-momentum cutoff at lower momentum in a perturbative treatment. Although the GCS saturates the minimal uncertainty in a simultaneous measurement of physical position and momentum operators, thus constituting the squeezed states, complete coherency is impossible in quantum gravitational physics. The Mandel Q number is calculated, and it is shown that the statistics can be Poissonian and super-/sub-Poissonian depending on γ. The equation of motion is studied, and both Ehrenfest’s theorem and the correspondence principle are recovered. Fractional revival times are obtained through the autocorrelation, and they indicate that the superposition of a classical-like subwave packet is natural in GCS. We also contrast our results with the string-motivated (Snyder) type of deformed quantum mechanics, which incorporates a minimum position uncertainty rather than a maximum momentum. With the advances of quantum optics technology, it might be possible to realize some of these distinguishing quantum-gravitational features within the domain of future experiments.

  8. Implementation of Complex Signal Processing Algorithms for Position-Sensitive Microcalorimeters

    NASA Technical Reports Server (NTRS)

    Smith, Stephen J.

    2008-01-01

    We have recently reported on a theoretical digital signal-processing algorithm for improved energy and position resolution in position-sensitive, transition-edge sensor (POST) X-ray detectors [Smith et al., Nucl, lnstr and Meth. A 556 (2006) 2371. PoST's consists of one or more transition-edge sensors (TES's) on a large continuous or pixellated X-ray absorber and are under development as an alternative to arrays of single pixel TES's. PoST's provide a means to increase the field-of-view for the fewest number of read-out channels. In this contribution we extend the theoretical correlated energy position optimal filter (CEPOF) algorithm (originally developed for 2-TES continuous absorber PoST's) to investigate the practical implementation on multi-pixel single TES PoST's or Hydras. We use numerically simulated data for a nine absorber device, which includes realistic detector noise, to demonstrate an iterative scheme that enables convergence on the correct photon absorption position and energy without any a priori assumptions. The position sensitivity of the CEPOF implemented on simulated data agrees very well with the theoretically predicted resolution. We discuss practical issues such as the impact of random arrival phase of the measured data on the performance of the CEPOF. The CEPOF algorithm demonstrates that full-width-at- half-maximum energy resolution of < 8 eV coupled with position-sensitivity down to a few 100 eV should be achievable for a fully optimized device.

  9. Two position optical element actuator device

    DOEpatents

    Holdener, Fred R.; Boyd, Robert D.

    2002-01-01

    The present invention is a two position optical element actuator device utilizing a powered means to hold an actuation arm, to which an optical element is attached, in a first position. A non-powered means drives the actuation arm to a second position, when the powered means ceases to receive power. The optical element may be a electromagnetic (EM) radiation or particle source, an instrument, or EM radiation or particle transmissive, reflective or absorptive elements. A bearing is used to transfer motion and smoothly transition the actuation arm from the first to second position.

  10. An investigation of rugby scrimmaging posture and individual maximum pushing force.

    PubMed

    Wu, Wen-Lan; Chang, Jyh-Jong; Wu, Jia-Hroung; Guo, Lan-Yuen

    2007-02-01

    Although rugby is a popular contact sport and the isokinetic muscle torque assessment has recently found widespread application in the field of sports medicine, little research has examined the factors associated with the performance of game-specific skills directly by using the isokinetic-type rugby scrimmaging machine. This study is designed to (a) measure and observe the differences in the maximum individual pushing forward force produced by scrimmaging in different body postures (3 body heights x 2 foot positions) with a self-developed rugby scrimmaging machine and (b) observe the variations in hip, knee, and ankle angles at different body postures and explore the relationship between these angle values and the individual maximum pushing force. Ten national rugby players were invited to participate in the examination. The experimental equipment included a self-developed rugby scrimmaging machine and a 3-dimensional motion analysis system. Our results showed that the foot positions (parallel and nonparallel foot positions) do not affect the maximum pushing force; however, the maximum pushing force was significantly lower in posture I (36% body height) than in posture II (38%) and posture III (40%). The maximum forward force in posture III (40% body height) was also slightly greater than for the scrum in posture II (38% body height). In addition, it was determined that hip, knee, and ankle angles under parallel feet positioning are factors that are closely negatively related in terms of affecting maximum pushing force in scrimmaging. In cross-feet postures, there was a positive correlation between individual forward force and hip angle of the rear leg. From our results, we can conclude that if the player stands in an appropriate starting position at the early stage of scrimmaging, it will benefit the forward force production. PMID:17313278

  11. The rediscovery of absorption chillers

    SciTech Connect

    Katzel, J.

    1992-04-23

    Absorption chillers are back - and for two very good reasons: they are environmentally sound and, in many cases, economically attractive. One factor fueling this resurgence is the outlook for natural gas, the energy source of most absorption systems. Deregulation has spurred exploration, and forecasts indicate an abundant supply and relatively low prices through 2050. Threats of global warming and depletion of the ozone layer also are forces driving the absorption chiller market. Being a good corporate citizen today means minimizing or eliminating the use of chlorofluorocarbons (CFCs), the basis of many refrigerants used in mechanical chillers. Even as chemical and chiller manufacturers alike work to develop substitute refrigerants, the perfect alternative has yet to be found. Absorption units are free of these problems, a benefit that appeals to many people.

  12. Maximum life spiral bevel reduction design

    NASA Technical Reports Server (NTRS)

    Savage, M.; Prasanna, M. G.; Coe, H. H.

    1992-01-01

    Optimization is applied to the design of a spiral bevel gear reduction for maximum life at a given size. A modified feasible directions search algorithm permits a wide variety of inequality constraints and exact design requirements to be met with low sensitivity to initial values. Gear tooth bending strength and minimum contact ratio under load are included in the active constraints. The optimal design of the spiral bevel gear reduction includes the selection of bearing and shaft proportions in addition to gear mesh parameters. System life is maximized subject to a fixed back-cone distance of the spiral bevel gear set for a specified speed ratio, shaft angle, input torque, and power. Significant parameters in the design are: the spiral angle, the pressure angle, the numbers of teeth on the pinion and gear, and the location and size of the four support bearings. Interpolated polynomials expand the discrete bearing properties and proportions into continuous variables for gradient optimization. After finding the continuous optimum, a designer can analyze near optimal designs for comparison and selection. Design examples show the influence of the bearing lives on the gear parameters in the optimal configurations. For a fixed back-cone distance, optimal designs with larger shaft angles have larger service lives.

  13. Portable measurement of maximum mouth pressures.

    PubMed

    Hamnegård, C H; Wragg, S; Kyroussis, D; Aquilina, R; Moxham, J; Green, M

    1994-02-01

    We have compared a small portable mouth pressure meter (MPM) to our laboratory standard (LS) pressure recording equipment in order to evaluate this new device. The mouth pressure meter measures and displays as a digital read-out peak pressure for inspiratory and expiratory efforts. It samples the signal at 16 Hz, and an integral microprocessor is programmed to determine and display the maximum pressure averaged over one second both during inspiratory and expiratory manoeuvres (PImax and PEmax, respectively). A fine bore catheter connecting the mouthpiece of the mouth pressure meter to a Validyne pressure transducer enabled simultaneous measurement of pressure, which was analysed by LabVIEW, running on a Macintosh Quadra 700 computer. We studied 13 normal subjects and 11 patients with respiratory disease. Each subject performed inspiratory and five expiratory efforts. The values displayed from the mouth pressure meter were manually recorded. The mouth pressure meter reliably and accurately measured peak pressure and maximal pressure both for inspiratory and expiratory efforts in normals and patients. The mean +/- SD difference when compared with the Validyne method was 0.19 +/- 0.12 and -0.04 +/- 0.12 kPa, for PImax and PEmax, respectively. This portable device should be useful to measure mouth pressures, not only in the routine lung function laboratory but also at the bedside and in the clinic. PMID:8162993

  14. Preparing for the Upcoming Solar Maximum

    NASA Astrophysics Data System (ADS)

    Tretkoff, Ernie

    2009-07-01

    As the next solar maximum approaches, society is increasingly reliant on satellite communications and navigation technologies, which are vulnerable to solar storms. To prepare for the upcoming peak in solar activity, expected in 2013, the U.S. National Space Weather Program Council organized the 2009 Space Weather Enterprise Forum, held 19-20 May in Washington, D. C. The conference, themed "Space Weather and Our Technological Society—Are We Ready for Solar Max?," attracted more than 225 participants, representing government agencies, industry, and academia. Presentations and panel discussion throughout the conference addressed issues including opportunities for coordinated collaboration among various agencies and with industry; the need for more effective outreach to stakeholders, policy makers, and the public; and ways to improve communication between scientists and space weather forecasters. Participants also agreed that it is important to plan for follow-up projects that will replace aging space weather satellites, such as the Advanced Composition Explorer (ACE), which provides continuous solar wind monitoring.

  15. Theoretical Estimate of Maximum Possible Nuclear Explosion

    DOE R&D Accomplishments Database

    Bethe, H. A.

    1950-01-31

    The maximum nuclear accident which could occur in a Na-cooled, Be moderated, Pu and power producing reactor is estimated theoretically. (T.R.H.) 2O82 Results of nuclear calculations for a variety of compositions of fast, heterogeneous, sodium-cooled, U-235-fueled, plutonium- and power-producing reactors are reported. Core compositions typical of plate-, pin-, or wire-type fuel elements and with uranium as metal, alloy, and oxide were considered. These compositions included atom ratios in the following range: U-23B to U-235 from 2 to 8; sodium to U-235 from 1.5 to 12; iron to U-235 from 5 to 18; and vanadium to U-235 from 11 to 33. Calculations were performed to determine the effect of lead and iron reflectors between the core and blanket. Both natural and depleted uranium were evaluated as the blanket fertile material. Reactors were compared on a basis of conversion ratio, specific power, and the product of both. The calculated results are in general agreement with the experimental results from fast reactor assemblies. An analysis of the effect of new cross-section values as they became available is included. (auth)

  16. Maximum windmill efficiency in finite time

    NASA Astrophysics Data System (ADS)

    Huleihil, Mahmoud

    2009-05-01

    The fraction of the kinetic energy of the wind impinging on the rotor-swept area that a wind turbine can convert to useful power has been shown by Betz in an idealized laminar-flow model to have an upper limit of 16/27 or 59% approximately [I. H. Shames, Mechanics of Fluids, 2nd ed. (McGraw-Hill, New York, 1982), pp. A26-A31]. This figure is known as Betz number. Other studies [A. Rauh and W. Seelret, Appl. Energy 17, 15 (1984)] suggested that this figure should be considered as a guideline. In this paper, a new model is introduced and its efficiency at maximum power output is derived. The derived value is shown to be a function of the Betz number B and given by the formula ηmp=1-√1-B . This value is 36.2%, which agrees well with those of actually operating wind turbines. As a guideline, the wind turbine efficiency can be considered to be within the range of the two numbers of merit, the Betz number and ηmp.

  17. Finding maximum JPEG image block code size

    NASA Astrophysics Data System (ADS)

    Lakhani, Gopal

    2012-07-01

    We present a study of JPEG baseline coding. It aims to determine the minimum storage needed to buffer the JPEG Huffman code bits of 8-bit image blocks. Since DC is coded separately, and the encoder represents each AC coefficient by a pair of run-length/AC coefficient level, the net problem is to perform an efficient search for the optimal run-level pair sequence. We formulate it as a two-dimensional, nonlinear, integer programming problem and solve it using a branch-and-bound based search method. We derive two types of constraints to prune the search space. The first one is given as an upper-bound for the sum of squares of AC coefficients of a block, and it is used to discard sequences that cannot represent valid DCT blocks. The second type constraints are based on some interesting properties of the Huffman code table, and these are used to prune sequences that cannot be part of optimal solutions. Our main result is that if the default JPEG compression setting is used, space of minimum of 346 bits and maximum of 433 bits is sufficient to buffer the AC code bits of 8-bit image blocks. Our implementation also pruned the search space extremely well; the first constraint reduced the initial search space of 4 nodes down to less than 2 nodes, and the second set of constraints reduced it further by 97.8%.

  18. Maximum likelihood continuity mapping for fraud detection

    SciTech Connect

    Hogden, J.

    1997-05-01

    The author describes a novel time-series analysis technique called maximum likelihood continuity mapping (MALCOM), and focuses on one application of MALCOM: detecting fraud in medical insurance claims. Given a training data set composed of typical sequences, MALCOM creates a stochastic model of sequence generation, called a continuity map (CM). A CM maximizes the probability of sequences in the training set given the model constraints, CMs can be used to estimate the likelihood of sequences not found in the training set, enabling anomaly detection and sequence prediction--important aspects of data mining. Since MALCOM can be used on sequences of categorical data (e.g., sequences of words) as well as real valued data, MALCOM is also a potential replacement for database search tools such as N-gram analysis. In a recent experiment, MALCOM was used to evaluate the likelihood of patient medical histories, where ``medical history`` is used to mean the sequence of medical procedures performed on a patient. Physicians whose patients had anomalous medical histories (according to MALCOM) were evaluated for fraud by an independent agency. Of the small sample (12 physicians) that has been evaluated, 92% have been determined fraudulent or abusive. Despite the small sample, these results are encouraging.

  19. TRENDS IN ESTIMATED MIXING DEPTH DAILY MAXIMUMS

    SciTech Connect

    Buckley, R; Amy DuPont, A; Robert Kurzeja, R; Matt Parker, M

    2007-11-12

    Mixing depth is an important quantity in the determination of air pollution concentrations. Fireweather forecasts depend strongly on estimates of the mixing depth as a means of determining the altitude and dilution (ventilation rates) of smoke plumes. The Savannah River United States Forest Service (USFS) routinely conducts prescribed fires at the Savannah River Site (SRS), a heavily wooded Department of Energy (DOE) facility located in southwest South Carolina. For many years, the Savannah River National Laboratory (SRNL) has provided forecasts of weather conditions in support of the fire program, including an estimated mixing depth using potential temperature and turbulence change with height at a given location. This paper examines trends in the average estimated mixing depth daily maximum at the SRS over an extended period of time (4.75 years) derived from numerical atmospheric simulations using two versions of the Regional Atmospheric Modeling System (RAMS). This allows for differences to be seen between the model versions, as well as trends on a multi-year time frame. In addition, comparisons of predicted mixing depth for individual days in which special balloon soundings were released are also discussed.

  20. CORA: Emission Line Fitting with Maximum Likelihood

    NASA Astrophysics Data System (ADS)

    Ness, Jan-Uwe; Wichmann, Rainer

    2011-12-01

    The advent of pipeline-processed data both from space- and ground-based observatories often disposes of the need of full-fledged data reduction software with its associated steep learning curve. In many cases, a simple tool doing just one task, and doing it right, is all one wishes. In this spirit we introduce CORA, a line fitting tool based on the maximum likelihood technique, which has been developed for the analysis of emission line spectra with low count numbers and has successfully been used in several publications. CORA uses a rigorous application of Poisson statistics. From the assumption of Poissonian noise we derive the probability for a model of the emission line spectrum to represent the measured spectrum. The likelihood function is used as a criterion for optimizing the parameters of the theoretical spectrum and a fixed point equation is derived allowing an efficient way to obtain line fluxes. As an example we demonstrate the functionality of the program with an X-ray spectrum of Capella obtained with the Low Energy Transmission Grating Spectrometer (LETGS) on board the Chandra observatory and choose the analysis of the Ne IX triplet around 13.5 Å.

  1. CORA - emission line fitting with Maximum Likelihood

    NASA Astrophysics Data System (ADS)

    Ness, J.-U.; Wichmann, R.

    2002-07-01

    The advent of pipeline-processed data both from space- and ground-based observatories often disposes of the need of full-fledged data reduction software with its associated steep learning curve. In many cases, a simple tool doing just one task, and doing it right, is all one wishes. In this spirit we introduce CORA, a line fitting tool based on the maximum likelihood technique, which has been developed for the analysis of emission line spectra with low count numbers and has successfully been used in several publications. CORA uses a rigorous application of Poisson statistics. From the assumption of Poissonian noise we derive the probability for a model of the emission line spectrum to represent the measured spectrum. The likelihood function is used as a criterion for optimizing the parameters of the theoretical spectrum and a fixed point equation is derived allowing an efficient way to obtain line fluxes. As an example we demonstrate the functionality of the program with an X-ray spectrum of Capella obtained with the Low Energy Transmission Grating Spectrometer (LETGS) on board the Chandra observatory and choose the analysis of the Ne IX triplet around 13.5 Å.

  2. Approach trajectory planning system for maximum concealment

    NASA Technical Reports Server (NTRS)

    Warner, David N., Jr.

    1986-01-01

    A computer-simulation study was undertaken to investigate a maximum concealment guidance technique (pop-up maneuver), which military aircraft may use to capture a glide path from masked, low-altitude flight typical of terrain following/terrain avoidance flight enroute. The guidance system applied to this problem is the Fuel Conservative Guidance System. Previous studies using this system have concentrated on the saving of fuel in basically conventional land and ship-based operations. Because this system is based on energy-management concepts, it also has direct application to the pop-up approach which exploits aircraft performance. Although the algorithm was initially designed to reduce fuel consumption, the commanded deceleration is at its upper limit during the pop-up and, therefore, is a good approximation of a minimum-time solution. Using the model of a powered-lift aircraft, the results of the study demonstrated that guidance commands generated by the system are well within the capability of an automatic flight-control system. Results for several initial approach conditions are presented.

  3. 46 CFR 154.556 - Cargo hose: Maximum working pressure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo hose: Maximum working pressure. 154.556 Section... Equipment Cargo Hose § 154.556 Cargo hose: Maximum working pressure. A cargo hose must have a maximum working pressure not less than the maximum pressure to which it may be subjected and at least 1034...

  4. 46 CFR 154.556 - Cargo hose: Maximum working pressure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Cargo hose: Maximum working pressure. 154.556 Section... Equipment Cargo Hose § 154.556 Cargo hose: Maximum working pressure. A cargo hose must have a maximum working pressure not less than the maximum pressure to which it may be subjected and at least 1034...

  5. 49 CFR 230.24 - Maximum allowable stress.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Maximum allowable stress. 230.24 Section 230.24... Allowable Stress § 230.24 Maximum allowable stress. (a) Maximum allowable stress value. The maximum allowable stress value on any component of a steam locomotive boiler shall not exceed 1/4 of the...

  6. 49 CFR 230.24 - Maximum allowable stress.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Maximum allowable stress. 230.24 Section 230.24... Allowable Stress § 230.24 Maximum allowable stress. (a) Maximum allowable stress value. The maximum allowable stress value on any component of a steam locomotive boiler shall not exceed 1/4 of the...

  7. 49 CFR 230.24 - Maximum allowable stress.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Maximum allowable stress. 230.24 Section 230.24... Allowable Stress § 230.24 Maximum allowable stress. (a) Maximum allowable stress value. The maximum allowable stress value on any component of a steam locomotive boiler shall not exceed 1/4 of the...

  8. 49 CFR 230.24 - Maximum allowable stress.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Maximum allowable stress. 230.24 Section 230.24... Allowable Stress § 230.24 Maximum allowable stress. (a) Maximum allowable stress value. The maximum allowable stress value on any component of a steam locomotive boiler shall not exceed 1/4 of the...

  9. 49 CFR 230.24 - Maximum allowable stress.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Maximum allowable stress. 230.24 Section 230.24... Allowable Stress § 230.24 Maximum allowable stress. (a) Maximum allowable stress value. The maximum allowable stress value on any component of a steam locomotive boiler shall not exceed 1/4 of the...

  10. Use of calibration targets in the measurement of 2.22-micron mineral absorption features in Thematic Mapper data

    NASA Technical Reports Server (NTRS)

    Elvidge, Christopher D.

    1987-01-01

    A mineral absorption index (MAI) has been developed to separate leaf water and mineral absorption in the 2.22-micron Thematic Mapper band. The MAI uses three baselines to estimate and subtract the absorption attributable to vegetation. Digital number data from calibration targets devoid of vegetation are used to establish the positions of the baselines in Thematic Mapper data.

  11. Absorption spectra of isomeric OH adducts of 1,3,7-trimethylxanthine

    SciTech Connect

    Vinchurkar, M.S.; Rao, B.S.M.; Mohan, H.; Mittal, J.P.; Schmidt, K.H.; Jonah, C.D.

    1997-04-17

    The reactions of OH{sup .}, O{sup .-}, and SO{sub 4}{sup .-} with 1,3,7-trimethylxanthine (caffeine) were studied by pulse radiolysis with optical and conductance detection techniques. The absorption spectra of transients formed in OH{sup .} reaction in neutral solutions exhibited peaks at 310 and 335 nm, as well as a broad absorption maximum at 500 nm, which decayed by first-order kinetics. The rate (k = (4.0 {+-} 0.5) x 10{sup 4} s{sup -1}) of this decay is independent of pH in the range 4-9 and is in agreement with that determined from the conductance detection (k = 4 x 10{sup 4} s{sup -1}). The spectrum in acidic solutions has only a broad peak around 330 nm with no absorption in the higher wavelength region. The intermediates formed in reaction of O{sup .-} absorb around 310 and at 350 nm, and the first-order decay at the latter wavelength was not seen. The OH radical adds to C-4 (X-40H{sup .}) and C-8 (X-80H{sup .}) positions of caffeine in the ratio 1:2 as determined from the redox titration and conductivity measurements. H abstraction from the methyl group is an additional reaction channel in O{sup .-} reaction. Dehydroxylation of the X-40H{sup .} adduct occurs, whereas the X-80H{sup .} adduct does not undergo ring opening. The spectrum obtained for OH{sup .} reaction in oxygenated solutions is similar to that observed in SO{sub 4}{sup .-} reaction in basic solutions. 25 refs., 5 figs., 1 tab.

  12. Electromagnetically induced absorption in detuned stub waveguides: a simple analytical and experimental model.

    PubMed

    Mouadili, A; Boudouti, E H El; Soltani, A; Talbi, A; Djafari-Rouhani, B; Akjouj, A; Haddadi, K

    2014-12-17

    We give an analytical and experimental demonstration of a classical analogue of the electromagnetic induced absorption (EIA) in a simple photonic device consisting of two stubs of lengths d1 and d2 grafted at the same site along a waveguide. By detuning the lengths of the two stubs (i.e. δ = d(2) - d(1)) we show that: (i) the amplitudes of the electromagnetic waves in the two stubs can be written following the two resonators model where each stub plays the role of a radiative resonator with low Q factor. The destructive interference between the waves in the two stubs may give rise to a sharp resonance peak with high Q factor in the transmission as well as in the absorption. (ii) The transmission coefficient around the resonance induced by the stubs can be written following a Fano-like form. In particular, we give an explicit expression of the position, width and Fano parameter of the resonances as a function of δ. (iii) By taking into account the loss in the waveguides, we show that at the transmission resonance, the transmission (reflection) increases (decreases) as a function of δ. Whereas the absorption goes through a maximum around 0.5 for a threshold value δth which depends on the attenuation in the system and then falls to zero. (iv) We give a comparison between the phase of the determinant of the scattering matrix, the so-called Friedel phase and the phase of the transmission amplitude. (v) The effect of the boundary conditions at the end of the resonators on the EIA resonance is also discussed. The analytical results are obtained by means of the Green's function method, whereas the experiments are carried out using coaxial cables in the radio-frequency regime. These results should have important consequences for designing integrated devices such as narrow-frequency optical or microwave filters and high-speed switches. PMID:25406973

  13. STARS: the Stellar Absorption and Refraction Sensor

    NASA Astrophysics Data System (ADS)

    Yee, Jeng-Hwa; Morrison, Daniel; Murphy, Graham A.; Morgan, M. F.; Humm, David C.; Silverglate, Peter R.; Vervack, Ronald; Paxton, Larry J.

    2002-01-01

    The Stellar Absorption and Refraction Sensor (STARS) is a compact, large-aperture instrument that combines a UV-IR imaging spectrograph with a co-aligned visible-light imager to make simultaneous absorptive and refractive stellar occultation measurements. The absorption measurements provided by the spectrograph allow the determination of vertical profiles of atmospheric constituents. The coincident refraction observations made by the image yield high-precision measurements of atmospheric density, pressure, and temperature and provide independent knowledge of both the refracted light path and Rayleigh extinction, which are critical in reducing the uncertainty in the retrieved constituent profiles in the lower atmosphere. STARS employs a two-axis gimbaled telescope to acquire and track the star and a two-axis, high-precision, fast-steering mirror to correct for spacecraft jitter and maintain the star within the spectrograph field of view. The relative star position measured by the imager provides position feedback to the active tracking loop of the fast-steering mirror. With funding from NASA's Instrument Incubator Program, a laboratory facility has been developed to demonstrate the overall instrument performance and, in particular, its capability to acquire and track a setting, refracting, and scintillating star, to compensate for various degrees of platform jitter, and to provide the pointing knowledge required for accurate determination of the atmospheric quantities. The combination of built-in image tracking and motion compensation capabilities, small size, and limited spacecraft resource requirements makes STARS and its tracking mechanism suitable for deployment on existing and future commercial spacecraft platforms for applications that require high-precision pointing. In this paper, we present details of the instrument design and its expected performance based on our laboratory tests.

  14. On the origins of C IV absorption profile diversity in broad absorption line quasars

    NASA Astrophysics Data System (ADS)

    Baskin, Alexei; Laor, Ari; Hamann, Fred

    2015-05-01

    There is a large diversity in the C IV broad absorption line (BAL) profile among BAL quasars (BALQs). We quantify this diversity by exploring the distribution of the C IV BAL properties, full width at half-maximum (FWHM), maximum depth of absorption and its velocity shift (vmd), using the Sloan Digital Sky Survey DR7 quasar catalogue. We find the following: (i) Although the median C IV BAL profile in the quasar rest-frame becomes broader and shallower as the UV continuum slope (αUV at 1700-3000 Å) gets bluer, the median individual profile in the absorber rest-frame remains identical, and is narrow (FWHM = 3500 km s-1) and deep. Only 4 per cent of BALs have FWHM > 10 000 km s-1. (ii) As the He II emission equivalent width (EW) decreases, the distributions of FWHM and vmd extend to larger values, and the median maximum depth increases. These trends are consistent with theoretical models in which softer ionizing continua reduce overionization, and allow radiative acceleration of faster BAL outflows. (iii) As αUV becomes bluer, the distribution of vmd extends to larger values. This trend may imply faster outflows at higher latitudes above the accretion disc plane. (iv) For non-BALQs, the C IV emission line decreases with decreasing He II EW, and becomes more asymmetric and blueshifted. This suggests an increasing relative contribution of emission from the BAL outflow to the C IV emission line as the ionizing spectral energy distribution (SED) gets softer, which is consistent with the increasing fraction of BALQs as the ionizing SED gets softer.

  15. Model of yield response of corn to plant population and absorption of solar energy.

    PubMed

    Overman, Allen R; Scholtz, Richard V

    2011-01-01

    Biomass yield of agronomic crops is influenced by a number of factors, including crop species, soil type, applied nutrients, water availability, and plant population. This article is focused on dependence of biomass yield (Mg ha(-1) and g plant(-1)) on plant population (plants m(-2)). Analysis includes data from the literature for three independent studies with the warm-season annual corn (Zea mays L.) grown in the United States. Data are analyzed with a simple exponential mathematical model which contains two parameters, viz. Y(m) (Mg ha(-1)) for maximum yield at high plant population and c (m(2) plant(-1)) for the population response coefficient. This analysis leads to a new parameter called characteristic plant population, x(c) = 1/c (plants m(-2)). The model is shown to describe the data rather well for the three field studies. In one study measurements were made of solar radiation at different positions in the plant canopy. The coefficient of absorption of solar energy was assumed to be the same as c and provided a physical basis for the exponential model. The three studies showed no definitive peak in yield with plant population, but generally exhibited asymptotic approach to maximum yield with increased plant population. Values of x(c) were very similar for the three field studies with the same crop species. PMID:21297960

  16. Model of Yield Response of Corn to Plant Population and Absorption of Solar Energy

    PubMed Central

    Overman, Allen R.; Scholtz, Richard V.

    2011-01-01

    Biomass yield of agronomic crops is influenced by a number of factors, including crop species, soil type, applied nutrients, water availability, and plant population. This article is focused on dependence of biomass yield (Mg ha−1 and g plant−1) on plant population (plants m−2). Analysis includes data from the literature for three independent studies with the warm-season annual corn (Zea mays L.) grown in the United States. Data are analyzed with a simple exponential mathematical model which contains two parameters, viz. Ym (Mg ha−1) for maximum yield at high plant population and c (m2 plant−1) for the population response coefficient. This analysis leads to a new parameter called characteristic plant population, xc = 1/c (plants m−2). The model is shown to describe the data rather well for the three field studies. In one study measurements were made of solar radiation at different positions in the plant canopy. The coefficient of absorption of solar energy was assumed to be the same as c and provided a physical basis for the exponential model. The three studies showed no definitive peak in yield with plant population, but generally exhibited asymptotic approach to maximum yield with increased plant population. Values of xc were very similar for the three field studies with the same crop species. PMID:21297960

  17. Target Acquisition and Positioning Study (TAPS)

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The Scientific Instruments for the Large Space Telescope (LST) require a high degree of accuracy for positioning targets within their respective entrance apertures. The acquisition, verification of position, and guidance during an experiment must be accomplished with a minimum loss of observing time for the maximum effectiveness of the total mission. This study evaluates several viable concepts and modes of operation that are applicable for a Target Acquisition and Positioning System (TAPS) that is responsive to the LST instrument requirements.

  18. Nebular Hydrogen Absorption in the Ejecta of Eta Carinae

    NASA Technical Reports Server (NTRS)

    Gull, Theodore R.; Ishibashi, K.; Davidson, K.; Fisher, Richard R. (Technical Monitor)

    2000-01-01

    Space Telescope Imaging Spectrograph (STIS) observations of Eta Carinae and immediate ejecta reveal narrow Balmer absorption lines in addition to the nebular-scattered broad P-Cygni absorptions. The narrow absorption correlates with apparent disk structure that separates the two Homunculus lobes. We trace these features about half way up the Northern lobe until the scattered stellar Balmer line doppler-shifts redward beyond the nebular absorption feature. Three-dimensional data cubes, made by mapping the Homunculus at Balmer alpha and Balmer beta with the 52 x 0.1 arcsecond aperture and about 5000 spectral resolving power, demonstrate that the absorption feature changes slowly in velocity with nebular position. We have monitored the stellar Balmer alpha line profile of the central source over the past four years. The equivalent width of the nebular absorption feature changes considerably between observations. The changes do not correlate with measured brightness of Eta Carinae. Likely clumps of neutral hydrogen with a scale size comparable to the stellar disk diameter are passing through the intervening light path on the timescales less than several months. The excitation mechanism involves Lyman alpha radiation (possibly the Lyman series plus Lyman continuum) and collisions leading to populating the 2S metastable state. Before the electron can jump to the ground state by two photon emission (lifetime about 1/8 second), a stellar Balmer photon is absorbed and the electron shifts to an NP level. We see the absorption feature in higher Balmer lines, and but not in Paschen lines. Indeed we see narrow nebular Paschen emission lines. At present, we do not completely understand the details of the absorption. Better understanding should lead to improved insight of the unique conditions around Eta Carinae that leads to these absorptions.

  19. Maximum Mouth Opening in Saudi Adolescents

    PubMed Central

    Al-Dlaigan, Yousef H; Asiry, Moshabab A

    2014-01-01

    Background: The aim of this study was to investigate the maximum mouth opening (MMO) in a representative sample of the Saudi adolescents. Materials and Methods: A total of 1825 Saudi adolescents (1007 males and 818 females) aged 12-16 years were randomly selected. The subjects were asked to open their mouth maximally till no further opening was possible and then the distance from the incisal edge of the maxillary incisors to incisal edge of the mandibular incisors was recorded. All data were analyzed using SPSS program and simple descriptive statistics of MMO with regard to gender and age groups were reported. The Student’s t-test and one-way analysis of variance were used to examine differences in mouth opening relative to gender and age groups. Results: The mean maximal mouth opening for males was 43.5 ± 4.23 mm (range 29-59 mm). The mean maximal mouth opening for females was 35.5 ± 4.4 mm (range 20-45 mm). There was a significant difference between the mouth opening of males and females in all the age group (P = 0.000). The mouth opening, regardless of gender, increases significantly with age from the age of 12 years to the age of 14 years (P = 0.000), then remained unchanged till the age of 16 years. Conclusion: The mouth opening of males is significantly higher than that of females in all the age group. There was a significant increase in MMO with age up to the age of 14 years regardless of gender. PMID:25628483

  20. A maximum likelihood framework for protein design

    PubMed Central

    Kleinman, Claudia L; Rodrigue, Nicolas; Bonnard, Cécile; Philippe, Hervé; Lartillot, Nicolas

    2006-01-01

    Background The aim of protein design is to predict amino-acid sequences compatible with a given target structure. Traditionally envisioned as a purely thermodynamic question, this problem can also be understood in a wider context, where additional constraints are captured by learning the sequence patterns displayed by natural proteins of known conformation. In this latter perspective, however, we still need a theoretical formalization of the question, leading to general and efficient learning methods, and allowing for the selection of fast and accurate objective functions quantifying sequence/structure compatibility. Results We propose a formulation of the protein design problem in terms of model-based statistical inference. Our framework uses the maximum likelihood principle to optimize the unknown parameters of a statistical potential, which we call an inverse potential to contrast with classical potentials used for structure prediction. We propose an implementation based on Markov chain Monte Carlo, in which the likelihood is maximized by gradient descent and is numerically estimated by thermodynamic integration. The fit of the models is evaluated by cross-validation. We apply this to a simple pairwise contact potential, supplemented with a solvent-accessibility term, and show that the resulting models have a better predictive power than currently available pairwise potentials. Furthermore, the model comparison method presented here allows one to measure the relative contribution of each component of the potential, and to choose the optimal number of accessibility classes, which turns out to be much higher than classically considered. Conclusion Altogether, this reformulation makes it possible to test a wide diversity of models, using different forms of potentials, or accounting for other factors than just the constraint of thermodynamic stability. Ultimately, such model-based statistical analyses may help to understand the forces shaping protein sequences, and

  1. Two-Photon Absorption of Metal-Assisted Chromophores.

    PubMed

    Li, Xin; Rinkevicius, Zilvinas; Ågren, Hans

    2014-12-01

    Aiming to understand the effect of a metal surface on nonlinear optical properties and the combined effects of surface and solvent environments on such properties, we present a multiscale response theory study, integrated with dynamics of the two-photon absorption of 4-nitro-4'-amino-trans-stilbene physisorbed on noble metal surfaces, considering two such surfaces, Ag(111) and Au(111), and two solvents, cyclohexane and water, as cases for demonstration. A few conclusions of general character could be drawn: While the geometrical change of the chromophore induced by the environment was found to notably alter (diminish) the two-photon absorption cross section in the polar medium, the effects of the metal surface and solvent on the electronic structure of the chromophore surpasses the geometrical effects and leads to a considerably enhanced two-photon absorption cross section in the polar solvent. This enhancement of two-photon absorption arises essentially from the metal charge image induced enlargement of the difference between the dipole moment of the excited state and the ground state. The orientation-dependence of the two-photon absorption is found to connect with the lateral rotation of the chromophore, where the two-photon absorption reaches its maximum when the polarization of the incident light coincides with the long-axis of the chromophore. Our results demonstrate a distinct enhancement of the two-photon absorption by a metal surface and a polar medium and envisage the employment of metal-chromophore composite materials for future development of nonlinear optical materials with desirable properties. PMID:26583246

  2. Automated Extraction of Absorption Bands from Reflectance Special

    NASA Technical Reports Server (NTRS)

    Huguenin, R. L.; Vale, L.; Mcintire, D.; Jones, J.

    1985-01-01

    A multiple high order derivative spectroscopy technique has been developed for deriving wavelength positions, half widths, and heights of absorption bands in reflectance spectra. The technique is applicable to laboratory spectra as well as medium resolution (100-200/cm) telescope or spacecraft spectra with moderate (few percent) noise. The technique permits absorption band positions to be detected with an accuracy of better than 3%, and often better than 1%. The high complexity of radiative transfer processes in diffusely reflected spectra can complicate the determination of absorption band positions. Continuum reflections, random illumination geometries within the material, phase angle effects, composite overlapping bands, and calibration uncertainties can shift apparent band positions by 20% from their actual positions or mask them beyond detection. Using multiple high order derivative analysis, effects of scattering continua, phase angle, and calibration (smooth features) are suppressed. Inflection points that characterize the positions and half widths of constituent bands are enhanced by the process and directly detected with relatively high sensitivity.

  3. Gauging the Nearness and Size of Cycle Maximum

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.; Hathaway, David H.

    2003-01-01

    A simple method for monitoring the nearness and size of conventional cycle maximum for an ongoing sunspot cycle is examined. The method uses the observed maximum daily value and the maximum monthly mean value of international sunspot number and the maximum value of the 2-mo moving average of monthly mean sunspot number to effect the estimation. For cycle 23, a maximum daily value of 246, a maximum monthly mean of 170.1, and a maximum 2-mo moving average of 148.9 were each observed in July 2000. Taken together, these values strongly suggest that conventional maximum amplitude for cycle 23 would be approx. 124.5, occurring near July 2002 +/-5 mo, very close to the now well-established conventional maximum amplitude and occurrence date for cycle 23-120.8 in April 2000.

  4. Maximum detection range limitation of pulse laser radar with Geiger-mode avalanche photodiode array

    NASA Astrophysics Data System (ADS)

    Luo, Hanjun; Xu, Benlian; Xu, Huigang; Chen, Jingbo; Fu, Yadan

    2015-05-01

    When designing and evaluating the performance of laser radar system, maximum detection range achievable is an essential parameter. The purpose of this paper is to propose a theoretical model of maximum detection range for simulating the Geiger-mode laser radar's ranging performance. Based on the laser radar equation and the requirement of the minimum acceptable detection probability, and assuming the primary electrons triggered by the echo photons obey Poisson statistics, the maximum range theoretical model is established. By using the system design parameters, the influence of five main factors, namely emitted pulse energy, noise, echo position, atmospheric attenuation coefficient, and target reflectivity on the maximum detection range are investigated. The results show that stronger emitted pulse energy, lower noise level, more front echo position in the range gate, higher atmospheric attenuation coefficient, and higher target reflectivity can result in greater maximum detection range. It is also shown that it's important to select the minimum acceptable detection probability, which is equivalent to the system signal-to-noise ratio for producing greater maximum detection range and lower false-alarm probability.

  5. Time-resolved pump and probe x-ray absorption fine structure spectroscopy at beamline P11 at PETRA III.

    PubMed

    Göries, D; Dicke, B; Roedig, P; Stübe, N; Meyer, J; Galler, A; Gawelda, W; Britz, A; Geßler, P; Sotoudi Namin, H; Beckmann, A; Schlie, M; Warmer, M; Naumova, M; Bressler, C; Rübhausen, M; Weckert, E; Meents, A

    2016-05-01

    We report about the development and implementation of a new setup for time-resolved X-ray absorption fine structure spectroscopy at beamline P11 utilizing the outstanding source properties of the low-emittance PETRA III synchrotron storage ring in Hamburg. Using a high intensity micrometer-sized X-ray beam in combination with two positional feedback systems, measurements were performed on the transition metal complex fac-Tris[2-phenylpyridinato-C2,N]iridium(III) also referred to as fac-Ir(ppy)3. This compound is a representative of the phosphorescent iridium(III) complexes, which play an important role in organic light emitting diode (OLED) technology. The experiment could directly prove the anticipated photoinduced charge transfer reaction. Our results further reveal that the temporal resolution of the experiment is limited by the PETRA III X-ray bunch length of ∼103 ps full width at half maximum (FWHM). PMID:27250401

  6. Absorption of different lead compounds

    PubMed Central

    Barltrop, D.; Meek, F.

    1975-01-01

    A rapid method for the determination of relative absorption of dietary lead by rats is described. The influence of age, weight and dose rate has been determined and using standard conditions the tissue lead content of blood, kidney and femur are significantly correlated with each other and are a function of ingested lead. Eight lead compounds were evaluated using this technique and the findings related to lead acetate as a reference compound. Of the inorganic preparations studied, lead carbonate (basic) and metallic lead showed a twelve-fold difference in absorption, with the remaining compounds giving intermediate values. The absorption of lead from four organic compounds was determined from diets containing 7·5% corn oil added to the standard diet. Lead tallate was absorbed to the same degree as lead acetate, but lesser absorptions resulted from lead octoate, naphthenate and alsynate. The addition of corn oil to a final concentration of 7·5% of the diet enhanced the absorption of lead acetate. PMID:1208290

  7. Positive position control of robotic manipulators

    NASA Technical Reports Server (NTRS)

    Baz, A.; Gumusel, L.

    1989-01-01

    The present, simple and accurate position-control algorithm, which is applicable to fast-moving and lightly damped robot arms, is based on the positive position feedback (PPF) strategy and relies solely on position sensors to monitor joint angles of robotic arms to furnish stable position control. The optimized tuned filters, in the form of a set of difference equations, manipulate position signals for robotic system performance. Attention is given to comparisons between this PPF-algorithm controller's experimentally ascertained performance characteristics and those of a conventional proportional controller.

  8. SPECTROPOLARIMETRY OF THE TYPE Ia SN 2007sr TWO MONTHS AFTER MAXIMUM LIGHT

    SciTech Connect

    Zelaya, P.; Quinn, J. R.; Clocchiatti, A.; Baade, D.; Patat, F.; Hoeflich, P.; Maund, J.; Wang, L.; Wheeler, J. C.

    2013-02-01

    We present late-time spectropolarimetric observations of SN 2007sr, obtained with the Very Large Telescope at the ESO Paranal Observatory when the object was 63 days after maximum light. The late-time spectrum displays strong line polarization in the Ca II absorption features. SN 2007sr adds to the case of some normal Type Ia supernovae that show high line polarization or repolarization at late times, a fact that might be connected with the presence of high-velocity features at early times.

  9. Proposed human stratum corneum water domain in chemical absorption.

    PubMed

    Zhu, Hanjiang; Jung, Eui-Chang; Hui, Xiaoying; Maibach, Howard

    2016-08-01

    Compounds with varying physical and chemical properties may have different affinities to the stratum corneum (SC) and/or its intercellular lipids, keratin protein, and possible water domains. To better understand the mechanism of percutaneous absorption, we utilized 21 carbon-14 labeled chemicals, with wide hydrophilicity (log P = -0.05 to 6.17), and quantified their absorption/adsorption properties for a short incubation time (15 min) with regards to intact SC membrane, delipidized SC membrane and SC lipid. A facile method was developed for SC/lipid absorption, providing a more equivalent procedure and comparable data. SC lipid absorption of chemical solutes positively correlated with the octanol/water partition coefficient (log P). Differences between the percent dose of chemical absorption to intact SC and the total percent dose contributed by the protein and lipid domains suggest the possibility and significance of a water domain. Absorption rate experiments showed a longer lag time for intact SC than for delipidized SC or SC lipid, suggesting that the water domain may delay chemical binding to protein and lipid domains, and may be a factor in the resistance of many chemicals to current decontamination methods. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26206725

  10. NOTE FROM THE EDITOR: Bayesian and Maximum Entropy Methods Bayesian and Maximum Entropy Methods

    NASA Astrophysics Data System (ADS)

    Dobrzynski, L.

    2008-10-01

    The Bayesian and Maximum Entropy Methods are now standard routines in various data analyses, irrespective of ones own preference to the more conventional approach based on so-called frequentists understanding of the notion of the probability. It is not the purpose of the Editor to show all achievements of these methods in various branches of science, technology and medicine. In the case of condensed matter physics most of the oldest examples of Bayesian analysis can be found in the excellent tutorial textbooks by Sivia and Skilling [1], and Bretthorst [2], while the application of the Maximum Entropy Methods were described in `Maximum Entropy in Action' [3]. On the list of questions addressed one finds such problems as deconvolution and reconstruction of the complicated spectra, e.g. counting the number of lines hidden within the spectrum observed with always finite resolution, reconstruction of charge, spin and momentum density distribution from an incomplete sets of data, etc. On the theoretical side one might find problems like estimation of interatomic potentials [4], application of the MEM to quantum Monte Carlo data [5], Bayesian approach to inverse quantum statistics [6], very general to statistical mechanics [7] etc. Obviously, in spite of the power of the Bayesian and Maximum Entropy Methods, it is not possible for everything to be solved in a unique way by application of these particular methods of analysis, and one of the problems which is often raised is connected not only with a uniqueness of a reconstruction of a given distribution (map) but also with its accuracy (error maps). In this `Comments' section we present a few papers showing more recent advances and views, and highlighting some of the aforementioned problems. References [1] Sivia D S and Skilling J 2006 Data Analysis: A Bayesian Tutorial 2nd edn (Oxford: Oxford University Press) [2] Bretthorst G L 1988 Bayesian Spectruim Analysis and Parameter Estimation (Berlin: Springer) [3] Buck B and

  11. Pattern formation, logistics, and maximum path probability

    NASA Astrophysics Data System (ADS)

    Kirkaldy, J. S.

    1985-05-01

    The concept of pattern formation, which to current researchers is a synonym for self-organization, carries the connotation of deductive logic together with the process of spontaneous inference. Defining a pattern as an equivalence relation on a set of thermodynamic objects, we establish that a large class of irreversible pattern-forming systems, evolving along idealized quasisteady paths, approaches the stable steady state as a mapping upon the formal deductive imperatives of a propositional function calculus. In the preamble the classical reversible thermodynamics of composite systems is analyzed as an externally manipulated system of space partitioning and classification based on ideal enclosures and diaphragms. The diaphragms have discrete classification capabilities which are designated in relation to conserved quantities by descriptors such as impervious, diathermal, and adiabatic. Differentiability in the continuum thermodynamic calculus is invoked as equivalent to analyticity and consistency in the underlying class or sentential calculus. The seat of inference, however, rests with the thermodynamicist. In the transition to an irreversible pattern-forming system the defined nature of the composite reservoirs remains, but a given diaphragm is replaced by a pattern-forming system which by its nature is a spontaneously evolving volume partitioner and classifier of invariants. The seat of volition or inference for the classification system is thus transferred from the experimenter or theoretician to the diaphragm, and with it the full deductive facility. The equivalence relations or partitions associated with the emerging patterns may thus be associated with theorems of the natural pattern-forming calculus. The entropy function, together with its derivatives, is the vehicle which relates the logistics of reservoirs and diaphragms to the analog logistics of the continuum. Maximum path probability or second-order differentiability of the entropy in isolation are

  12. Alkali absorption and citrate excretion in calcium nephrolithiasis

    NASA Technical Reports Server (NTRS)

    Sakhaee, K.; Williams, R. H.; Oh, M. S.; Padalino, P.; Adams-Huet, B.; Whitson, P.; Pak, C. Y.

    1993-01-01

    The role of net gastrointestinal (GI) alkali absorption in the development of hypocitraturia was investigated. The net GI absorption of alkali was estimated from the difference between simple urinary cations (Ca, Mg, Na, and K) and anions (Cl and P). In 131 normal subjects, the 24 h urinary citrate was positively correlated with the net GI absorption of alkali (r = 0.49, p < 0.001). In 11 patients with distal renal tubular acidosis (RTA), urinary citrate excretion was subnormal relative to net GI alkali absorption, with data from most patients residing outside the 95% confidence ellipse described for normal subjects. However, the normal relationship between urinary citrate and net absorbed alkali was maintained in 11 patients with chronic diarrheal syndrome (CDS) and in 124 stone-forming patients devoid of RTA or CDS, half of whom had "idiopathic" hypocitraturia. The 18 stone-forming patients without RTA or CDS received potassium citrate (30-60 mEq/day). Both urinary citrate and net GI alkali absorption increased, yielding a significantly positive correlation (r = 0.62, p < 0.0001), with the slope indistinguishable from that of normal subjects. Thus, urinary citrate was normally dependent on the net GI absorption of alkali. This dependence was less marked in RTA, confirming the renal origin of hypocitraturia. However, the normal dependence was maintained in CDS and in idiopathic hypocitraturia, suggesting that reduced citrate excretion was largely dietary in origin as a result of low net alkali absorption (from a probable relative deficiency of vegetables and fruits or a relative excess of animal proteins).

  13. Thermodynamic derivatives of infrared absorptance

    NASA Technical Reports Server (NTRS)

    Broersma, S.; Walls, W. L.

    1974-01-01

    Calculation of the concentration, pressure, and temperature dependence of the spectral absorptance of a vibrational absorption band. A smooth thermodynamic dependence was found for wavelength intervals where the average absorptance is less than 0.65. Individual rotational lines, whose parameters are often well known, were used as bases in the calculation of medium resolution spectra. Two modes of calculation were combined: well-separated rotational lines plus interaction terms, or strongly overlapping lines that were represented by a compound line of similar shape plus corrections. The 1.9- and 6.3-micron bands of H2O and the 4.3-micron band of CO2 were examined in detail and compared with experiment.

  14. Absorption properties of identical atoms

    SciTech Connect

    Sancho, Pedro

    2013-09-15

    Emission rates and other optical properties of multi-particle systems in collective and entangled states differ from those in product ones. We show the existence of similar effects in the absorption probabilities for (anti)symmetrized states of two identical atoms. The effects strongly depend on the overlapping between the atoms and differ for bosons and fermions. We propose a viable experimental verification of these ideas. -- Highlights: •The absorption rates of a pair of identical atoms in product and (anti)symmetrized states are different. •The modifications of the optical properties are essentially determined by the overlapping between the atoms. •The absorption properties differ, in some cases, for bosons and fermions.

  15. Nonstationary Analysis of Annual Maximum Streamflow of Canada

    NASA Astrophysics Data System (ADS)

    Yew Gan, Thian; Tan, Xuezhi

    2016-04-01

    Both natural climate change and anthropogenic impacts may cause nonstationarities in hydrological ex-tremes. In this study, long-term annual maximum streamflow (AMS) records from 145 stations over Canada were used to investigate the nonstationary characteristics of AMS, which include abrupt changes and monotonic temporal trends. The nonparameteric Pettitt test was applied to detect abrupt changes, while temporal monotonic trend analysis in AMS series was conducted using the nonparameteric Mann-Kendall and Spearman tests, as well as a parametric Pearson test. Nonstationary frequency analysis of the AMS series was done using a group of nonstationary probability distributions. The nonstationary characteristics of Ca-nadian AMS were further investigated in terms of the Hurst exponent (H), which represents the long-term persistence (LTP) of streamflow data. The results presented here indicate that for Canadian AMS data, abrupt changes are detected more frequently than monotonic trends, partly because many rivers began to be regulated in the twentieth century. Drainage basins that have experienced significant land-use changes are more likely to show temporal trends in AMS, compared to pristine basins with stable land-use conditions. The nonstationary characteristics of AMS were accounted for by fitting the data with probability distributions with time-varying parameters. Large H found in almost 2/ 3 of the Canadian AMS dataset indicates strong LTP, which may partly represent the presence of long-term memories in many Canadian river basins. Furthermore, H values of AMS data are positively correlated with the basin area of Canadian rivers. It seems that non-stationary frequency analysis, instead of the traditional stationary hydrologic frequency analysis, should be employed in the future. Reference: Tan, X., and Gan, T. Y., 2015, Nonstationary analysis of annual maximum streamflow of Canada, Journal of Climate, DOI: 10.1175/JCLI-D-14-00538.1

  16. Enhanced absorption cycle computer model

    NASA Astrophysics Data System (ADS)

    Grossman, G.; Wilk, M.

    1993-09-01

    Absorption heat pumps have received renewed and increasing attention in the past two decades. The rising cost of electricity has made the particular features of this heat-powered cycle attractive for both residential and industrial applications. Solar-powered absorption chillers, gas-fired domestic heat pumps, and waste-heat-powered industrial temperature boosters are a few of the applications recently subjected to intensive research and development. The absorption heat pump research community has begun to search for both advanced cycles in various multistage configurations and new working fluid combinations with potential for enhanced performance and reliability. The development of working absorption systems has created a need for reliable and effective system simulations. A computer code has been developed for simulation of absorption systems at steady state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system's components and property subroutines containing thermodynamic properties of the working fluids. The user conveys to the computer an image of his cycle by specifying the different subunits and their interconnections. Based on this information, the program calculates the temperature, flow rate, concentration, pressure, and vapor fraction at each state point in the system, and the heat duty at each unit, from which the coefficient of performance (COP) may be determined. This report describes the code and its operation, including improvements introduced into the present version. Simulation results are described for LiBr-H2O triple-effect cycles, LiCl-H2O solar-powered open absorption cycles, and NH3-H2O single-effect and generator-absorber heat exchange cycles. An appendix contains the user's manual.

  17. Finding Quantitative Trait Loci Genes with Collaborative Targeted Maximum Likelihood Learning.

    PubMed

    Wang, Hui; Rose, Sherri; van der Laan, Mark J

    2011-07-01

    Quantitative trait loci mapping is focused on identifying the positions and effect of genes underlying an an observed trait. We present a collaborative targeted maximum likelihood estimator in a semi-parametric model using a newly proposed 2-part super learning algorithm to find quantitative trait loci genes in listeria data. Results are compared to the parametric composite interval mapping approach. PMID:21572586

  18. Finding Quantitative Trait Loci Genes with Collaborative Targeted Maximum Likelihood Learning

    PubMed Central

    Wang, Hui; Rose, Sherri; van der Laan, Mark J.

    2010-01-01

    Quantitative trait loci mapping is focused on identifying the positions and effect of genes underlying an an observed trait. We present a collaborative targeted maximum likelihood estimator in a semi-parametric model using a newly proposed 2-part super learning algorithm to find quantitative trait loci genes in listeria data. Results are compared to the parametric composite interval mapping approach. PMID:21572586

  19. Solar powered absorption air conditioning

    NASA Astrophysics Data System (ADS)

    Vardon, J. M.

    1980-04-01

    Artificial means of providing or removing heat from the building are discussed along with the problem of the appropriate building design and construction for a suitable heat climate inside the building. The use of a lithium bromide-water absorption chiller, powered by a hot water store heated by an array of stationary flat collectors, is analyzed. An iterative method of predicting the cooling output from a LiBr-water absorption refrigeration plant having variable heat input is described and a model allowing investigation of the performance of a solar collector and thermal storage system is developed.

  20. Periodic microwave absorption in superconductors

    SciTech Connect

    Martinek, J.; Stankowski, J. )

    1994-08-01

    A model explaining the presence of a periodic train of microwave absorption lines in the magnetic modulated microwave absorption (MMMA) spectra of high- and low-temperature superconductors is proposed. The model assumes the occurrence of regular superconducting current loops, closed by Josephson junctions, in these materials. The system of such loops is considered within the basic model of the rf superconducting quantum interference device taking into account the effect of thermal fluctuations. The magnetic-field and temperature dependencies of the MMMA obtained on the basis of the proposed model are in qualitative agreement with experimental data.

  1. Absorption-heat-pump system

    DOEpatents

    Grossman, G.; Perez-Blanco, H.

    1983-06-16

    An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

  2. The isolation of prophyra-334 from marine algae and its UV-absorption behavior

    NASA Astrophysics Data System (ADS)

    Zhaohui, Zhang; Xin, Gao; Tashiro, Yuri; Matsukawa, Shingo; Ogawa, Hiroo

    2005-12-01

    Prophyra-334 was prepared by methanol extraction and HPLC methods from marine algae (dried laver). It is a sunscreen compound that has good absorption of ultraviolet radiations in the wavelength ranges of 200-400 nm. The absorption maximum wavelength of prophyra-334 is at 334 nm, so defined the name. The molar extinction coefficient (ɛ) of prophyra-334 in aqueous solution at 334 nm wavelength is 4.23×104. The absorption of prophyra-334 in organic solvents differs in aqueous solutions. In polar organic solvents, the absorption maximum wavelength of prophyra-334 has a slight shift toward longer wavelength compared with that in pure water. On the contrary, in inert non-polar organic solvents, the absorption maximum wavelength and the shape of absorption spectra of prophyra-334 are changed. The effects of organic solvents on prophyra-334 stability suggested that: (1) the absorbance of prophyra-334 in water is generally constant at temperature of 60°C in 24 h, meaning that prophyra-334 is quite stable in water; (2) the absorbance of prophyra-334 in ethanol and hexane decreases at the same condition. The stability of prophyra-334 in organic solvents is less than that in aqueous solution. In benzene, the prophyra-334 is very instable.

  3. DISCOVERY OF THE TRANSITION OF A MINI-BROAD ABSORPTION LINE INTO A BROAD ABSORPTION LINE IN THE SDSS QUASAR J115122.14+020426.3

    SciTech Connect

    Hidalgo, Paola Rodriguez; Eracleous, Michael; Charlton, Jane; Hamann, Fred; Murphy, Michael T.; Nestor, Daniel

    2013-09-20

    We present the detection of a rare case of dramatic strengthening in the UV absorption profiles in the spectrum of the quasar J115122.14+020426.3 between observations {approx}2.86 yr apart in the quasar rest frame. A spectrum obtained in 2001 by the Sloan Digital Sky Survey shows a C IV ''mini-broad'' absorption line (FWHM = 1220 km s{sup -1}) with a maximum blueshift velocity of {approx}9520 km s{sup -1}, while a later spectrum from the Very Large Telescope shows a significantly broader and stronger absorption line, with a maximum blueshift velocity of {approx}12, 240 km s{sup -1} that qualifies as a broad absorption line. A similar variability pattern is observed in two additional systems at lower blueshifted velocities and in the Ly{alpha} and N V transitions as well. One of the absorption systems appears to be resolved and shows evidence for partial covering of the quasar continuum source (C{sub f} {approx} 0.65), indicating a transverse absorber size of, at least, {approx}6 Multiplication-Sign 10{sup 16} cm. In contrast, a cluster of narrower C IV lines appears to originate in gas that fully covers the continuum and broad emission line sources. There is no evidence for changes in the centroid velocity of the absorption troughs. This case suggests that at least some of the absorbers that produce ''mini-broad'' and broad absorption lines in quasar spectra do not belong to intrinsically separate classes. Here, the ''mini-broad'' absorption line is most likely interpreted as an intermediate phase before the appearance of a broad absorption line due to their similar velocities. While the current observations do not provide enough constraints to discern among the possible causes for this variability, future monitoring of multiple transitions at high resolution will help achieve this goal.

  4. Solving maximum cut problems in the Adleman-Lipton model.

    PubMed

    Xiao, Dongmei; Li, Wenxia; Zhang, Zhizhou; He, Lin

    2005-12-01

    In this paper, we consider a procedure for solving maximum cut problems in the Adleman-Lipton model. The procedure works in O(n2) steps for maximum cut problems of an undirected graph with n vertices. PMID:16236426

  5. 33 CFR 183.35 - Maximum weight capacity: Outboard boats.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... difference between its maximum displacement and boat weight. (b) For the purposes of paragraph (a) of this section: (1) “Maximum displacement” is the weight of the volume of water displaced by the boat at...

  6. Maximum urban heat island intensity in a medium-sized coastal Mediterranean city

    NASA Astrophysics Data System (ADS)

    Papanastasiou, Dimitris K.; Kittas, Constantinos

    2012-02-01

    This paper studies the maximum intensity of the urban heat island (UHI) that develops in Volos urban area, a medium-sized coastal city in central Greece. The maximum temperature difference between the city center and a suburb is 3.4°C and 3.1°C during winter and summer, respectively, while during both seasons the average maximum UHI intensity is 2.0°C. The UHI usually starts developing after sunset during both seasons. It could be attributed to the different nocturnal radiative cooling rate and to the different anthropogenic heat emission rate that are observed at the city center and at the suburb, as well as to meteorological conditions. The analysis reveals that during both seasons the daily maximum hourly (DMH) UHI intensity is positively correlated with solar radiation and with previous day's maximum hourly UHI intensity and negatively correlated with wind speed. It is also negatively correlated with relative humidity during winter but positively correlated with it during summer. This difference could be attributed to the different mechanisms that mainly drive humidity levels (i.e., evaporation in winter and sea breeze (SB) in summer). Moreover, it is found that SB development triggers a delay in UHI formation in summer. The impact of atmospheric pollution on maximum UHI intensity is also examined. An increase in PM10 concentration is associated with an increase in maximum UHI intensity during winter and with a decrease during summer. The impact of PM10 on UHI is caused by the attenuation of the incoming and the outgoing radiation. Additionally, this study shows that the weekly cycle of the city activities induces a weekly variation in maximum UHI intensity levels. The weekly range of DMH UHI intensity is not very large, being more pronounced during winter (0.4°C). Moreover, a first attempt is made to predict the DMH UHI intensity by applying regression models, whose success is rather promising.

  7. Assessment of specific energy absorption rate (SAR) in the head from a TETRA handset.

    PubMed

    Dimbylow, Peter; Khalid, Mohammed; Mann, Simon

    2003-12-01

    Finite-difference time-domain (FDTD) calculations of the specific energy absorption rate (SAR) from a representative TETRA handset have been performed in an anatomically realistic model of the head. TETRA (Terrestrial Trunked Radio) is a modern digital private mobile radio system designed to meet the requirements of professional users, such as the police and fire brigade. The current frequency allocations in the UK are 380-385 MHz and 390-395 MHz for the public sector network. A comprehensive set of calculations of SAR in the head was performed for positions of the handset in front of the face and at both sides of the head. The representative TETRA handset considered. operating at 1 W in normal use, will show compliance with both the ICNIRP occupational and public exposure restrictions. The handset with a monopole antenna operating at 3 W in normal use will show compliance with both the ICNIRP occupational and public exposure restrictions. The handset with a helical antenna operating at 3 W in normal use will show compliance with the ICNIRP occupational exposure restriction but will be over the public exposure restriction by up to approximately 50% if kept in the position of maximum SAR for 6 min continuously. PMID:14703166

  8. AFGL atmospheric absorption line parameters compilation - 1982 edition

    NASA Technical Reports Server (NTRS)

    Rothman, L. S.; Gamache, R. R.; Barbe, A.; Goldman, A.; Gillis, J. R.; Brown, L. R.; Toth, R. A.; Flaud, J.-M.; Camy-Peyret, C.

    1983-01-01

    The latest edition of the AFGL atmospheric absorption line parameters compilation for the seven most active infrared terrestrial absorbers is described. Major modifications to the atlas for this edition include updating of water-vapor parameters from 0 to 4300 per cm, improvements to line positions for carbon dioxide, substantial modifications to the ozone bands in the middle to far infrared, and improvements to the 7- and 2.3-micron bands of methane. The atlas now contains about 181,000 rotation and vibration-rotation transitions between 0 and 17,900 per cm. The sources of the absorption parameters are summarized.

  9. Aerosol Absorption Measurements in MILAGRO.

    NASA Astrophysics Data System (ADS)

    Gaffney, J. S.; Marley, N. A.; Arnott, W. P.; Paredes-Miranda, L.; Barnard, J. C.

    2007-12-01

    During the month of March 2006, a number of instruments were used to determine the absorption characteristics of aerosols found in the Mexico City Megacity and nearby Valley of Mexico. These measurements were taken as part of the Department of Energy's Megacity Aerosol Experiment - Mexico City (MAX-Mex) that was carried out in collaboration with the Megacity Interactions: Local and Global Research Observations (MILAGRO) campaign. MILAGRO was a joint effort between the DOE, NSF, NASA, and Mexican agencies aimed at understanding the impacts of a megacity on the urban and regional scale. A super-site was operated at the Instituto Mexicano de Petroleo in Mexico City (designated T-0) and at the Universidad Technologica de Tecamac (designated T-1) that was located about 35 km to the north east of the T-0 site in the State of Mexico. A third site was located at a private rancho in the State of Hidalgo approximately another 35 km to the northeast (designated T-2). Aerosol absorption measurements were taken in real time using a number of instruments at the T-0 and T-1 sites. These included a seven wavelength aethalometer, a multi-angle absorption photometer (MAAP), and a photo-acoustic spectrometer. Aerosol absorption was also derived from spectral radiometers including a multi-filter rotating band spectral radiometer (MFRSR). The results clearly indicate that there is significant aerosol absorption by the aerosols in the Mexico City megacity region. The absorption can lead to single scattering albedo reduction leading to values below 0.5 under some circumstances. The absorption is also found to deviate from that expected for a "well-behaved" soot anticipated from diesel engine emissions, i.e. from a simple 1/lambda wavelength dependence for absorption. Indeed, enhanced absorption is seen in the region of 300-450 nm in many cases, particularly in the afternoon periods indicating that secondary organic aerosols are contributing to the aerosol absorption. This is likely due

  10. 31 CFR 149.3 - Maximum obligation limitation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance: Treasury 1 2014-07-01 2014-07-01 false Maximum obligation limitation. 149.3 Section 149.3 Money and Finance: Treasury Regulations Relating to Money and Finance MONETARY OFFICES, DEPARTMENT OF THE TREASURY CALCULATION OF MAXIMUM OBLIGATION LIMITATION § 149.3 Maximum obligation...

  11. 30 CFR 56.19062 - Maximum acceleration and deceleration.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Maximum acceleration and deceleration. 56.19062... Hoisting Hoisting Procedures § 56.19062 Maximum acceleration and deceleration. Maximum normal operating acceleration and deceleration shall not exceed 6 feet per second per second. During emergency braking,...

  12. 30 CFR 57.19062 - Maximum acceleration and deceleration.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Maximum acceleration and deceleration. 57.19062... Hoisting Hoisting Procedures § 57.19062 Maximum acceleration and deceleration. Maximum normal operating acceleration and deceleration shall not exceed 6 feet per second per second. During emergency braking,...

  13. 30 CFR 57.19062 - Maximum acceleration and deceleration.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Maximum acceleration and deceleration. 57.19062... Hoisting Hoisting Procedures § 57.19062 Maximum acceleration and deceleration. Maximum normal operating acceleration and deceleration shall not exceed 6 feet per second per second. During emergency braking,...

  14. 30 CFR 56.19062 - Maximum acceleration and deceleration.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Maximum acceleration and deceleration. 56.19062... Hoisting Hoisting Procedures § 56.19062 Maximum acceleration and deceleration. Maximum normal operating acceleration and deceleration shall not exceed 6 feet per second per second. During emergency braking,...

  15. 30 CFR 57.19062 - Maximum acceleration and deceleration.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Maximum acceleration and deceleration. 57.19062... Hoisting Hoisting Procedures § 57.19062 Maximum acceleration and deceleration. Maximum normal operating acceleration and deceleration shall not exceed 6 feet per second per second. During emergency braking,...

  16. 30 CFR 57.19062 - Maximum acceleration and deceleration.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Maximum acceleration and deceleration. 57.19062... Hoisting Hoisting Procedures § 57.19062 Maximum acceleration and deceleration. Maximum normal operating acceleration and deceleration shall not exceed 6 feet per second per second. During emergency braking,...

  17. 30 CFR 56.19062 - Maximum acceleration and deceleration.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Maximum acceleration and deceleration. 56.19062... Hoisting Hoisting Procedures § 56.19062 Maximum acceleration and deceleration. Maximum normal operating acceleration and deceleration shall not exceed 6 feet per second per second. During emergency braking,...

  18. 30 CFR 56.19062 - Maximum acceleration and deceleration.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Maximum acceleration and deceleration. 56.19062... Hoisting Hoisting Procedures § 56.19062 Maximum acceleration and deceleration. Maximum normal operating acceleration and deceleration shall not exceed 6 feet per second per second. During emergency braking,...

  19. 30 CFR 56.19062 - Maximum acceleration and deceleration.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Maximum acceleration and deceleration. 56.19062... Hoisting Hoisting Procedures § 56.19062 Maximum acceleration and deceleration. Maximum normal operating acceleration and deceleration shall not exceed 6 feet per second per second. During emergency braking,...

  20. 30 CFR 57.19062 - Maximum acceleration and deceleration.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Maximum acceleration and deceleration. 57.19062... Hoisting Hoisting Procedures § 57.19062 Maximum acceleration and deceleration. Maximum normal operating acceleration and deceleration shall not exceed 6 feet per second per second. During emergency braking,...

  1. 14 CFR 25.1505 - Maximum operating limit speed.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Maximum operating limit speed. 25.1505... Operating Limitations § 25.1505 Maximum operating limit speed. The maximum operating limit speed (V MO/M MO airspeed or Mach Number, whichever is critical at a particular altitude) is a speed that may not...

  2. 14 CFR 25.1505 - Maximum operating limit speed.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Maximum operating limit speed. 25.1505... Operating Limitations § 25.1505 Maximum operating limit speed. The maximum operating limit speed (V MO/M MO airspeed or Mach Number, whichever is critical at a particular altitude) is a speed that may not...

  3. 14 CFR 25.1505 - Maximum operating limit speed.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Maximum operating limit speed. 25.1505... Operating Limitations § 25.1505 Maximum operating limit speed. The maximum operating limit speed (V MO/M MO airspeed or Mach Number, whichever is critical at a particular altitude) is a speed that may not...

  4. 49 CFR 230.27 - Maximum shearing strength of rivets.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Maximum shearing strength of rivets. 230.27 Section 230.27 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Appurtenances Strength of Materials § 230.27 Maximum shearing strength of rivets. The maximum shearing...

  5. 14 CFR 375.23 - Maximum allowable weights.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Maximum allowable weights. 375.23 Section... Applicable § 375.23 Maximum allowable weights. Foreign civil aircraft that are permitted to navigate in the... maximum certificated weights prescribed or authorized for the particular variation of the aircraft...

  6. 33 CFR 183.35 - Maximum weight capacity: Outboard boats.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Maximum weight capacity: Outboard... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Safe Loading § 183.35 Maximum weight capacity: Outboard boats. (a) The maximum weight capacity marked on a boat that is designed or intended...

  7. 14 CFR 375.23 - Maximum allowable weights.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Maximum allowable weights. 375.23 Section... Applicable § 375.23 Maximum allowable weights. Foreign civil aircraft that are permitted to navigate in the... maximum certificated weights prescribed or authorized for the particular variation of the aircraft...

  8. 33 CFR 183.35 - Maximum weight capacity: Outboard boats.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Maximum weight capacity: Outboard... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Safe Loading § 183.35 Maximum weight capacity: Outboard boats. (a) The maximum weight capacity marked on a boat that is designed or intended...

  9. 49 CFR 236.55 - Dead section; maximum length.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Dead section; maximum length. 236.55 Section 236... Instructions: All Systems Track Circuits § 236.55 Dead section; maximum length. Where dead section exceeds 35... over such dead section is less than 35 feet, the maximum length of the dead section shall not...

  10. 49 CFR 236.55 - Dead section; maximum length.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Dead section; maximum length. 236.55 Section 236... Instructions: All Systems Track Circuits § 236.55 Dead section; maximum length. Where dead section exceeds 35... over such dead section is less than 35 feet, the maximum length of the dead section shall not...

  11. 49 CFR 236.55 - Dead section; maximum length.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Dead section; maximum length. 236.55 Section 236... Instructions: All Systems Track Circuits § 236.55 Dead section; maximum length. Where dead section exceeds 35... over such dead section is less than 35 feet, the maximum length of the dead section shall not...

  12. 49 CFR 236.55 - Dead section; maximum length.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Dead section; maximum length. 236.55 Section 236... Instructions: All Systems Track Circuits § 236.55 Dead section; maximum length. Where dead section exceeds 35... over such dead section is less than 35 feet, the maximum length of the dead section shall not...

  13. 49 CFR 236.55 - Dead section; maximum length.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Dead section; maximum length. 236.55 Section 236... Instructions: All Systems Track Circuits § 236.55 Dead section; maximum length. Where dead section exceeds 35... over such dead section is less than 35 feet, the maximum length of the dead section shall not...

  14. 49 CFR 230.27 - Maximum shearing strength of rivets.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Strength of Materials § 230.27 Maximum shearing strength of rivets. The maximum shearing strength... 49 Transportation 4 2012-10-01 2012-10-01 false Maximum shearing strength of rivets....

  15. 49 CFR 230.27 - Maximum shearing strength of rivets.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Strength of Materials § 230.27 Maximum shearing strength of rivets. The maximum shearing strength... 49 Transportation 4 2013-10-01 2013-10-01 false Maximum shearing strength of rivets....

  16. 49 CFR 230.27 - Maximum shearing strength of rivets.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Strength of Materials § 230.27 Maximum shearing strength of rivets. The maximum shearing strength... 49 Transportation 4 2014-10-01 2014-10-01 false Maximum shearing strength of rivets....

  17. Maximum Power Training and Plyometrics for Cross-Country Running.

    ERIC Educational Resources Information Center

    Ebben, William P.

    2001-01-01

    Provides a rationale for maximum power training and plyometrics as conditioning strategies for cross-country runners, examining: an evaluation of training methods (strength training and maximum power training and plyometrics); biomechanic and velocity specificity (role in preventing injury); and practical application of maximum power training and…

  18. 49 CFR 230.27 - Maximum shearing strength of rivets.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Strength of Materials § 230.27 Maximum shearing strength of rivets. The maximum shearing strength... 49 Transportation 4 2010-10-01 2010-10-01 false Maximum shearing strength of rivets....

  19. 40 CFR 141.13 - Maximum contaminant levels for turbidity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Maximum contaminant levels for turbidity. 141.13 Section 141.13 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Maximum Contaminant Levels § 141.13 Maximum contaminant levels for turbidity....

  20. 40 CFR 141.13 - Maximum contaminant levels for turbidity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Maximum contaminant levels for turbidity. 141.13 Section 141.13 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Maximum Contaminant Levels § 141.13 Maximum contaminant levels for turbidity....

  1. 40 CFR 143.3 - Secondary maximum contaminant levels.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Secondary maximum contaminant levels. 143.3 Section 143.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL SECONDARY DRINKING WATER REGULATIONS § 143.3 Secondary maximum contaminant levels. The secondary maximum contaminant...

  2. 43 CFR 3594.1 - Ultimate maximum recovery.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Ultimate maximum recovery. 3594.1 Section...) EXPLORATION AND MINING OPERATIONS Mining Methods § 3594.1 Ultimate maximum recovery. (a) Mining operations shall be conducted in a manner to yield the ultimate maximum recovery of the mineral...

  3. 43 CFR 3594.1 - Ultimate maximum recovery.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Ultimate maximum recovery. 3594.1 Section...) EXPLORATION AND MINING OPERATIONS Mining Methods § 3594.1 Ultimate maximum recovery. (a) Mining operations shall be conducted in a manner to yield the ultimate maximum recovery of the mineral...

  4. 43 CFR 3594.1 - Ultimate maximum recovery.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Ultimate maximum recovery. 3594.1 Section...) EXPLORATION AND MINING OPERATIONS Mining Methods § 3594.1 Ultimate maximum recovery. (a) Mining operations shall be conducted in a manner to yield the ultimate maximum recovery of the mineral...

  5. 43 CFR 3594.1 - Ultimate maximum recovery.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Ultimate maximum recovery. 3594.1 Section...) EXPLORATION AND MINING OPERATIONS Mining Methods § 3594.1 Ultimate maximum recovery. (a) Mining operations shall be conducted in a manner to yield the ultimate maximum recovery of the mineral...

  6. 31 CFR 149.3 - Maximum obligation limitation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance: Treasury 1 2013-07-01 2013-07-01 false Maximum obligation limitation. 149.3 Section 149.3 Money and Finance: Treasury Regulations Relating to Money and Finance MONETARY OFFICES, DEPARTMENT OF THE TREASURY CALCULATION OF MAXIMUM OBLIGATION LIMITATION § 149.3 Maximum obligation...

  7. 5 CFR 550.106 - Annual maximum earnings limitation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Annual maximum earnings limitation. 550.106 Section 550.106 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PAY ADMINISTRATION (GENERAL) Premium Pay Maximum Earnings Limitations § 550.106 Annual maximum earnings limitation. (a)(1) For any pay period...

  8. 5 CFR 550.105 - Biweekly maximum earnings limitation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Biweekly maximum earnings limitation. 550.105 Section 550.105 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PAY ADMINISTRATION (GENERAL) Premium Pay Maximum Earnings Limitations § 550.105 Biweekly maximum earnings limitation. (a) Except as provided...

  9. 7 CFR 4290.840 - Maximum term of Financing.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Financing of Enterprises by RBICs Structuring Rbic Financing of Eligible Enterprises-Types of Financings § 4290.840 Maximum term of Financing. The maximum term of any Debt Security must be no longer than 20... 7 Agriculture 15 2010-01-01 2010-01-01 false Maximum term of Financing. 4290.840 Section...

  10. 14 CFR 25.1505 - Maximum operating limit speed.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maximum operating limit speed. 25.1505... Operating Limitations § 25.1505 Maximum operating limit speed. The maximum operating limit speed (V MO/M MO airspeed or Mach Number, whichever is critical at a particular altitude) is a speed that may not...

  11. 14 CFR 25.1505 - Maximum operating limit speed.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maximum operating limit speed. 25.1505... Operating Limitations § 25.1505 Maximum operating limit speed. The maximum operating limit speed (V MO/M MO airspeed or Mach Number, whichever is critical at a particular altitude) is a speed that may not...

  12. 40 CFR 94.107 - Determination of maximum test speed.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... specified in 40 CFR 1065.510. These data points form the lug curve. It is not necessary to generate the... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Determination of maximum test speed... Determination of maximum test speed. (a) Overview. This section specifies how to determine maximum test...

  13. 40 CFR 94.107 - Determination of maximum test speed.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... specified in 40 CFR 1065.510. These data points form the lug curve. It is not necessary to generate the... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Determination of maximum test speed... Determination of maximum test speed. (a) Overview. This section specifies how to determine maximum test...

  14. Maximum Performance Tests in Children with Developmental Spastic Dysarthria.

    ERIC Educational Resources Information Center

    Wit, J.; And Others

    1993-01-01

    Three Maximum Performance Tasks (Maximum Sound Prolongation, Fundamental Frequency Range, and Maximum Repetition Rate) were administered to 11 children (ages 6-11) with spastic dysarthria resulting from cerebral palsy and 11 controls. Despite intrasubject and intersubject variability in normal and pathological speakers, the tasks were found to be…

  15. Accounting for self-absorption in calculation of light collection in plastic scintillators

    NASA Astrophysics Data System (ADS)

    Senchyshyn, V.; Lebedev, V.; Adadurov, A.; Budagov, J.; Chirikov-Zorin, I.

    2006-10-01

    This paper concerns Monte Carlo calculations of light collection in plastic scintillators with accounting for self-absorption. Two approaches are compared: a monochrome one, which takes into account light absorption at a wavelength of the emission spectra maximum, and a spectral one, which accounts for the absorption dependence on a wave length over the whole range of scintillating photon emission. Both approaches are used in light yield calculations for OPERA and Super-Nemo detectors. It is shown that the monochrome approach overestimates light collection values 1.5-2 times, while the spectral one leads to better agreement with experiment.

  16. Optimization on microlattice materials for sound absorption by an integrated transfer matrix method.

    PubMed

    Cai, Xiaobing; Yang, Jun; Hu, Gengkai

    2015-04-01

    Materials with well-defined microlattice structures are superlight, stable, and thus bear great potential in sound absorption. An integrated transfer matrix method (TMM) is proposed to evaluate the sound absorbing efficiency of these lattice materials, in which a massive number of micropores are densely placed. A comparison between integrated TMM and conventional TMM reveals that the proposed approach offers better predictions on sound absorption of microlattice. This approach is then employed to optimize the microlattice material to determine the best pore and porosity that lead to maximum absorbing efficiency capability and minimum required thickness to attain a target sound absorption. PMID:25920886

  17. Tripling the maximum imaging depth with third-harmonic generation microscopy.

    PubMed

    Yildirim, Murat; Durr, Nicholas; Ben-Yakar, Adela

    2015-09-01

    The growing interest in performing high-resolution, deep-tissue imaging has galvanized the use of longer excitation wavelengths and three-photon-based techniques in nonlinear imaging modalities. This study presents a threefold improvement in maximum imaging depth of ex vivo porcine vocal folds using third-harmonic generation (THG) microscopy at 1552-nm excitation wavelength compared to two-photon microscopy (TPM) at 776-nm excitation wavelength. The experimental, analytical, and Monte Carlo simulation results reveal that THG improves the maximum imaging depth observed in TPM significantly from 140 to 420 μm in a highly scattered medium, reaching the expected theoretical imaging depth of seven extinction lengths. This value almost doubles the previously reported normalized imaging depths of 3.5 to 4.5 extinction lengths using three-photon-based imaging modalities. Since tissue absorption is substantial at the excitation wavelength of 1552 nm, this study assesses the tissue thermal damage during imaging by obtaining the depth-resolved temperature distribution through a numerical simulation incorporating an experimentally obtained thermal relaxation time (τ). By shuttering the laser for a period of 2τ, the numerical algorithm estimates a maximum temperature increase of ∼2°C at the maximum imaging depth of 420 μm. The paper demonstrates that THG imaging using 1552 nm as an illumination wavelength with effective thermal management proves to be a powerful deep imaging modality for highly scattering and absorbing tissues, such as scarred vocal folds. PMID:26376941

  18. Tripling the maximum imaging depth with third-harmonic generation microscopy

    NASA Astrophysics Data System (ADS)

    Yildirim, Murat; Durr, Nicholas; Ben-Yakar, Adela

    2015-09-01

    The growing interest in performing high-resolution, deep-tissue imaging has galvanized the use of longer excitation wavelengths and three-photon-based techniques in nonlinear imaging modalities. This study presents a threefold improvement in maximum imaging depth of ex vivo porcine vocal folds using third-harmonic generation (THG) microscopy at 1552-nm excitation wavelength compared to two-photon microscopy (TPM) at 776-nm excitation wavelength. The experimental, analytical, and Monte Carlo simulation results reveal that THG improves the maximum imaging depth observed in TPM significantly from 140 to 420 μm in a highly scattered medium, reaching the expected theoretical imaging depth of seven extinction lengths. This value almost doubles the previously reported normalized imaging depths of 3.5 to 4.5 extinction lengths using three-photon-based imaging modalities. Since tissue absorption is substantial at the excitation wavelength of 1552 nm, this study assesses the tissue thermal damage during imaging by obtaining the depth-resolved temperature distribution through a numerical simulation incorporating an experimentally obtained thermal relaxation time (τ). By shuttering the laser for a period of 2τ, the numerical algorithm estimates a maximum temperature increase of ˜2°C at the maximum imaging depth of 420 μm. The paper demonstrates that THG imaging using 1552 nm as an illumination wavelength with effective thermal management proves to be a powerful deep imaging modality for highly scattering and absorbing tissues, such as scarred vocal folds.

  19. Two-photon absorption spectrum of the photoinitiator Lucirin TPO-L

    NASA Astrophysics Data System (ADS)

    Mendonca, C. R.; Correa, D. S.; Baldacchini, T.; Tayalia, P.; Mazur, E.

    2008-03-01

    Two-photon absorption induced polymerization provides a powerful method for the fabrication of intricate three-dimensional microstructures. Recently, Lucirin TPO-L was shown to be a photoinitiator with several advantageous properties for two-photon induced polymerization. Here we measure the two-photon absorption cross-section spectrum of Lucirin TPO-L, which presents a maximum of 1.2 GM at 610 nm. Despite its small two-photon absorption cross-section, it is possible to fabricate excellent microstructures by two-photon polymerization due to the high polymerization quantum yield of Lucirin TPO-L. These results indicate that optimization of the two-photon absorption cross-section is not the only material parameter to be considered when searching for new photoinitiators for microfabrication via two-photon absorption.

  20. Ultraviolet and Light Absorption Spectrometry.

    ERIC Educational Resources Information Center

    Hargis, L. G.; Howell, J. A.

    1984-01-01

    Reviews developments in ultraviolet and light absorption spectrometry from December 1981 through November 1983, focusing on the chemistry involved in developing suitable reagents, absorbing systems, and methods of determination, and on physical aspects of the procedures. Includes lists of spectrophotometric methods for metals, non-metals, and…

  1. Slow light and saturable absorption

    NASA Astrophysics Data System (ADS)

    Selden, A. C.

    2009-06-01

    Quantitative analysis of slow light experiments utilising coherent population oscillation (CPO) in a range of saturably absorbing media, including ruby and alexandrite, Er3+:Y2SiO5, bacteriorhodopsin, semiconductor quantum devices and erbium-doped optical fibres, shows that the observations may be more simply interpreted as saturable absorption phenomena. A basic two-level model of a saturable absorber displays all the effects normally associated with slow light, namely phase shift and modulation gain of the transmitted signal, hole burning in the modulation frequency spectrum and power broadening of the spectral hole, each arising from the finite response time of the non-linear absorption. Only where hole-burning in the optical spectrum is observed (using independent pump and probe beams), or pulse delays exceeding the limits set by saturable absorption are obtained, can reasonable confidence be placed in the observation of slow light in such experiments. Superluminal (“fast light”) phenomena in media with reverse saturable absorption (RSA) may be similarly explained.

  2. Migrant labor absorption in Malaysia.

    PubMed

    Nayagam, J

    1992-01-01

    The use of migrant workers to ease labor shortages caused by rapid industrialization in Malaysia during the twentieth century is examined. "This paper will focus on: (1) the extent, composition and distribution of migrant workers; (2) the labor shortage and absorption of migrant workers; and (3) the role of migrant workers in the government's economic restructuring process." PMID:12285766

  3. Upper limits for absorption by water vapor in the near-UV

    NASA Astrophysics Data System (ADS)

    Wilson, Eoin M.; Wenger, John C.; Venables, Dean S.

    2016-02-01

    There are few experimental measurements of absorption by water vapor in the near-UV. Here we report the results of spectral measurements of water vapor absorption at ambient temperature and pressure from 325 nm to 420 nm, covering most tropospherically relevant short wavelengths. Spectra were recorded using a broadband optical cavity in the chemically controlled environment of an atmospheric simulation chamber. No absorption attributable to the water monomer (or the dimer) was observed at the 0.5 nm resolution of our system. Our results are consistent with calculated spectra and recent DOAS field observations, but contradict a report of significant water absorption in the near-UV. Based on the detection limit of our instrument, we report upper limits for the water absorption cross section of less than 5×10-26 cm2 molecule-1 at our instrument resolution. For a typical, indicative slant column density of 4×1023 cm2, we calculate a maximum optical depth of 0.02 arising from absorption of water vapor in the atmosphere at wavelengths between 340 nm and 420 nm, with slightly higher maximum optical depths below 340 nm. The results of this work, together with recent atmospheric observations and computational results, suggest that water vapor absorption across most of the near-UV is small compared to visible and infrared wavelengths.

  4. Intergrating cavity absorption meter measurements of dissolved substances and suspended particles in ocean water

    NASA Astrophysics Data System (ADS)

    Pope, Robin M.; Weidemann, Alan D.; Fry, Edward S.

    2000-01-01

    We have developed a new device to measure the separate contributions to the spectral absorption coefficient due to a pure liquid, due to the particles suspended in it, and due to the substances dissolved in it. This device, the Integrating Cavity Absorption Meter (ICAM), is essentially independent of scattering effects in the sample. In April 1993, a prototype of the ICAM was field tested on board the research vessel USNS Bartlett. A major part of the cruise track included criss-crossing the area where the Mississippi flows into the Gulf of Mexico at various ranges from the mouth of the river; thus samples were collected from areas of blue, green, and brown/black water. We evaluated 35 seawater samples collected with 5-l Niskin bottles from 22 locations to determine absorption spectra (380-700 nm) of suspended particles and dissolved substances (gelbstoff). Results validate the ICAM as a viable tool for marine optical absorption research. Gelbstoff absorption at 432.5 nm ranged from 0.024 to 0.603 m -1. Over the spectral region 380→560 nm, gelbstoff absorption by each of the samples could be accurately fit to a decaying exponential. The particle absorption spectra are generally characteristic of those of phytoplankton and exhibit a local maximum at 430-440 nm. Absorption values at 432.5 nm ranged from ˜zero to ˜1.0 m -1. Some samples with moderate particulate absorption, however, did not show the characteristic local maximum of phytoplankton in the blue and instead resembled the characteristic decaying exponential of detritus with a shape similar to that observed in the gelbstoff. The ratio of gelbstoff to particulate absorption at 432.5 nm ranged from 0.46 to 152.

  5. Constructing valid density matrices on an NMR quantum information processor via maximum likelihood estimation

    NASA Astrophysics Data System (ADS)

    Singh, Harpreet; Arvind; Dorai, Kavita

    2016-09-01

    Estimation of quantum states is an important step in any quantum information processing experiment. A naive reconstruction of the density matrix from experimental measurements can often give density matrices which are not positive, and hence not physically acceptable. How do we ensure that at all stages of reconstruction, we keep the density matrix positive? Recently a method has been suggested based on maximum likelihood estimation, wherein the density matrix is guaranteed to be positive definite. We experimentally implement this protocol on an NMR quantum information processor. We discuss several examples and compare with the standard method of state estimation.

  6. Infrared absorption spectra of molecular crystals: Possible evidence for small-polaron formation?

    NASA Astrophysics Data System (ADS)

    Pržulj, Željko; Čevizović, Dalibor; Zeković, Slobodan; Ivić, Zoran

    2008-09-01

    The temperature dependence of the position of the so-called anomalous band peaked at 1650cm in the IR-absorption spectrum of crystalline acetanilide (ACN) is theoretically investigated within the small-polaron theory. Its pronounced shift towards the position of the normal band is predicted with the rise of temperature. Interpretation of the IR-absorption spectra in terms of small-polaron model has been critically assessed on the basis of these results.

  7. Revisiting the Generalization of Entropy for Non-positive Distribution: Application for Exponent Spectra Analysis

    NASA Astrophysics Data System (ADS)

    Kalaidzidis, Yannis L.; Gopta, Oxana; Kalaidzidis, Inna V.

    2009-12-01

    Originally the maximum entropy method for exponent deconvolution was restricted to the positive exponent's amplitudes by the entropy S(f, m) definition. It limits application of the method, since many experimental kinetics show both the rise and the decay, which manifest themselves as positive and negative amplitudes in the exponent spectrum. The generalization of entropy formulation for non-negative distribution (S. F. Gull and J. Skilling) overcomes this limitation. The drawback of the approach was, that m lost the meaning of the prior distribution, since that maximum of generalized S(f, m) is independent on m and achieved at f ≡ 0. It is significant problem when there are apriori information about possible spectrum behaviour. In the present work some assumptions of the entropy generalization was relaxed and alternative entropy formulation, with non-uniform prior was used for analysis of simulated and experimental data. The new approach was applied to spectra analysis of the absorption kinetics of the bacteriorhodopsin (bR—light driven proton pump from archea Halobacterium salinarium) photocycle. It was shown that the process of the intermediate M formation is non-exponential in the wild type bR. The non-exponential process could be interpreted as result of the protein conformational changes during proton transfer from the Shiff-base of bR.

  8. Design for Manufacturing for Energy Absorption Systems

    SciTech Connect

    Del Prete, A.; Primo, T.; Papadia, G.; Manisi, B.

    2011-05-04

    In the typical scenario of a helicopter crash, impact with the ground is preceded by a substantially vertical drop, with the result that a seated occupant of a helicopter experiences high spinal loads and pelvic deceleration during such crash due to the sudden arresting of vertical downward motion. It has long been recognized that spinal injuries to occupants of helicopters in such crash scenario can be minimized by seat arrangements which limit the deceleration to which the seated occupant is subjected, relative to the helicopter, to a predetermined maximum, by allowing downward movement of the seated occupant relative to the helicopter, at the time of impact with the ground, under a restraining force which, over a limited range of such movement, is limited to a predetermined maximum. In practice, significant benefits, in the way of reduced injuries and reduced seriousness of injuries, can be afforded in this way in such crash situations even where the extent of such controlled vertical movement permitted by the crashworthy seat arrangement is quite limited. Important increase of accident safety is reached with the installation of crashworthy shock absorbers on the main landing gear, but this solution is mostly feasible on military helicopters with long fixed landing gear. Seats can then give high contribution to survivability. Commonly, an energy absorber is a constant load device, if one excludes an initial elastic part of the load-stroke curve. On helicopter seats, this behavior is obtained by plastic deformation of a metal component or scraping of material. In the present work the authors have studied three absorption systems, which differ in relation to their shape, their working conditions and their constructive materials. All the combinations have been analyzed for applications in VIP helicopter seats.

  9. Design for Manufacturing for Energy Absorption Systems

    NASA Astrophysics Data System (ADS)

    Del Prete, A.; Primo, T.; Papadia, G.; Manisi, B.

    2011-05-01

    In the typical scenario of a helicopter crash, impact with the ground is preceded by a substantially vertical drop, with the result that a seated occupant of a helicopter experiences high spinal loads and pelvic deceleration during such crash due to the sudden arresting of vertical downward motion. It has long been recognized that spinal injuries to occupants of helicopters in such crash scenario can be minimized by seat arrangements which limit the deceleration to which the seated occupant is subjected, relative to the helicopter, to a predetermined maximum, by allowing downward movement of the seated occupant relative to the helicopter, at the time of impact with the ground, under a restraining force which, over a limited range of such movement, is limited to a predetermined maximum. In practice, significant benefits, in the way of reduced injuries and reduced seriousness of injuries, can be afforded in this way in such crash situations even where the extent of such controlled vertical movement permitted by the crashworthy seat arrangement is quite limited. Important increase of accident safety is reached with the installation of crashworthy shock absorbers on the main landing gear, but this solution is mostly feasible on military helicopters with long fixed landing gear. Seats can then give high contribution to survivability. Commonly, an energy absorber is a constant load device, if one excludes an initial elastic part of the load-stroke curve. On helicopter seats, this behavior is obtained by plastic deformation of a metal component or scraping of material. In the present work the authors have studied three absorption systems, which differ in relation to their shape, their working conditions and their constructive materials. All the combinations have been analyzed for applications in VIP helicopter seats.

  10. Bicarbonate absorption stimulates active calcium absorption in the rat proximal tubule.

    PubMed Central

    Bomsztyk, K; Calalb, M B

    1988-01-01

    To evaluate the effect of luminal bicarbonate on calcium reabsorption, rat proximal tubules were perfused in vivo. Perfusion solution contained mannitol to reduce water flux to zero. Total Ca concentration was measured by atomic absorption spectrometry, Ca ion concentration in the tubule lumen (CaL2+) and the peritubular capillary (CaP2+), and luminal pH (pHL) with ion-selective microelectrodes and transepithelial voltage (VTE) with conventional microelectrodes. When tubules were perfused with buffer-free Cl-containing solution, net Ca absorption (JCa) averaged 3.33 pmol/min. Even though VTE was 1.64 mV lumen-positive, CaL2+, 1.05 mM, did not fall below the concentration in the capillary blood, 1.07 mM. When 27 mM of Cl was replaced with HCO3, there was luminal fluid acidification. Despite a decrease in VTE and CaL2+, JCa increased to 7.13 pmol/min, indicating that the enhanced JCa could not be accounted for by the reduced electrochemical gradient, delta CCa. When acetazolamide or an analogue of amiloride was added to the HCO3 solution, JCa was not different from the buffer-free solution, suggesting that HCO3-stimulated JCa may be linked to acidification. To further test this hypothesis, we used 27 mM Hepes as the luminal buffer. With Hepes there was luminal fluid acidification and JCa was not different from the buffer-free solution but delta CCa was significantly reduced, indicating enhanced active calcium transport. We conclude from the results of the present study that HCO3 stimulates active Ca absorption, a process that may be linked to acidification-mediated HCO3 absorption. PMID:3366902

  11. Optimization of multi-element airfoils for maximum lift

    NASA Technical Reports Server (NTRS)

    Olsen, L. E.

    1979-01-01

    Two theoretical methods are presented for optimizing multi-element airfoils to obtain maximum lift. The analyses assume that the shapes of the various high lift elements are fixed. The objective of the design procedures is then to determine the optimum location and/or deflection of the leading and trailing edge devices. The first analysis determines the optimum horizontal and vertical location and the deflection of a leading edge slat. The structure of the flow field is calculated by iteratively coupling potential flow and boundary layer analysis. This design procedure does not require that flow separation effects be modeled. The second analysis determines the slat and flap deflection required to maximize the lift of a three element airfoil. This approach requires that the effects of flow separation from one or more of the airfoil elements be taken into account. The theoretical results are in good agreement with results of a wind tunnel test used to corroborate the predicted optimum slat and flap positions.

  12. Robust Deep Network with Maximum Correntropy Criterion for Seizure Detection

    PubMed Central

    Wang, Yueming; Zhu, Junming; Zheng, Xiaoxiang

    2014-01-01

    Effective seizure detection from long-term EEG is highly important for seizure diagnosis. Existing methods usually design the feature and classifier individually, while little work has been done for the simultaneous optimization of the two parts. This work proposes a deep network to jointly learn a feature and a classifier so that they could help each other to make the whole system optimal. To deal with the challenge of the impulsive noises and outliers caused by EMG artifacts in EEG signals, we formulate a robust stacked autoencoder (R-SAE) as a part of the network to learn an effective feature. In R-SAE, the maximum correntropy criterion (MCC) is proposed to reduce the effect of noise/outliers. Unlike the mean square error (MSE), the output of the new kernel MCC increases more slowly than that of MSE when the input goes away from the center. Thus, the effect of those noises/outliers positioned far away from the center can be suppressed. The proposed method is evaluated on six patients of 33.6 hours of scalp EEG data. Our method achieves a sensitivity of 100% and a specificity of 99%, which is promising for clinical applications. PMID:25105136

  13. On the maximum-entropy/autoregressive modeling of time series

    NASA Technical Reports Server (NTRS)

    Chao, B. F.

    1984-01-01

    The autoregressive (AR) model of a random process is interpreted in the light of the Prony's relation which relates a complex conjugate pair of poles of the AR process in the z-plane (or the z domain) on the one hand, to the complex frequency of one complex harmonic function in the time domain on the other. Thus the AR model of a time series is one that models the time series as a linear combination of complex harmonic functions, which include pure sinusoids and real exponentials as special cases. An AR model is completely determined by its z-domain pole configuration. The maximum-entropy/autogressive (ME/AR) spectrum, defined on the unit circle of the z-plane (or the frequency domain), is nothing but a convenient, but ambiguous visual representation. It is asserted that the position and shape of a spectral peak is determined by the corresponding complex frequency, and the height of the spectral peak contains little information about the complex amplitude of the complex harmonic functions.

  14. Ankle moment generation and maximum-effort curved sprinting performance.

    PubMed

    Luo, Geng; Stefanyshyn, Darren

    2012-11-15

    Turning at high speed along acute curves is crucial for athletic performance. One determinant of curved sprinting speed is the ground reaction force that can be created by the supporting limb; the moment generated at the ankle joint may influence such force generation. Body lean associated with curved sprints positions the ankle joints in extreme in-/eversion, and may hinder the ankle moment generation. To examine the influence of ankle moment generation on curved sprinting performance, 17 male subjects performed maximum-effort curved sprints in footwear with and without a wedge. The wedged footwear was constructed with the intention to align the ankle joints closer to their neutral frontal-plane configuration during counter-clockwise curved sprints so greater joint moments might be generated. We found, with the wedged footwear, the average eversion angle of the inside leg ankle was reduced, and the plantarflexion moment generation increased significantly. Meanwhile, the knee extension moment remained unchanged. With the wedged footwear, stance-average centripetal ground reaction force increased significantly while no difference in the vertical ground reaction force was detected. The subjects created a greater centripetal ground reaction impulse in the wedged footwear despite a shortened stance phase when compared to the control. Stance-average curved sprinting speed improved by 4.3% with the wedged footwear. The changes in ankle moment and curved sprinting speed observed in the current study supports the notion that the moment generation at the ankle joint may be a performance constraint for curved sprinting. PMID:23022207

  15. Fluorescence resonance energy transfer imaging by maximum likelihood estimation

    NASA Astrophysics Data System (ADS)

    Zhang, Yupeng; Yuan, Yumin; Holmes, Timothy J.

    2004-06-01

    Fluorescence resonance energy transfer (FRET) is a fluorescence microscope imaging process involving nonradiative energy transfer between two fluorophores (the donor and the acceptor). FRET is used to detect the chemical interactions and, in some cases, measure the distance between molecules. Existing approaches do not always well compensate for bleed-through in excitation, cross-talk in emission detection and electronic noise in image acquisition. We have developed a system to automatically search for maximum-likelihood estimates of the FRET image, donor concentration and acceptor concentration. It also produces other system parameters, such as excitation/emission filter efficiency and FRET conversion factor. The mathematical model is based upon a Poisson process since the CCD camera is a photon-counting device. The main advantage of the approach is that it automatically compensates for bleed-through and cross-talk degradations. Tests are presented with synthetic images and with real data referred to as positive and negative controls, where FRET is known to occur and to not occur, respectively. The test results verify the claimed advantages by showing consistent accuracy in detecting FRET and by showing improved accuracy in calculating FRET efficiency.

  16. Robust deep network with maximum correntropy criterion for seizure detection.

    PubMed

    Qi, Yu; Wang, Yueming; Zhang, Jianmin; Zhu, Junming; Zheng, Xiaoxiang

    2014-01-01

    Effective seizure detection from long-term EEG is highly important for seizure diagnosis. Existing methods usually design the feature and classifier individually, while little work has been done for the simultaneous optimization of the two parts. This work proposes a deep network to jointly learn a feature and a classifier so that they could help each other to make the whole system optimal. To deal with the challenge of the impulsive noises and outliers caused by EMG artifacts in EEG signals, we formulate a robust stacked autoencoder (R-SAE) as a part of the network to learn an effective feature. In R-SAE, the maximum correntropy criterion (MCC) is proposed to reduce the effect of noise/outliers. Unlike the mean square error (MSE), the output of the new kernel MCC increases more slowly than that of MSE when the input goes away from the center. Thus, the effect of those noises/outliers positioned far away from the center can be suppressed. The proposed method is evaluated on six patients of 33.6 hours of scalp EEG data. Our method achieves a sensitivity of 100% and a specificity of 99%, which is promising for clinical applications. PMID:25105136

  17. Effect of lapatinib on oral digoxin absorption in patients.

    PubMed

    Koch, Kevin M; Smith, Deborah A; Botbyl, Jeff; Arya, Nikita; Briley, Linda P; Cartee, Leanne; White, Jane Holshouser; Beyer, Jennifer; Dar, Mohammed M; Chung, Hyun Choel; Chu, Quincy; Bang, Yung-Jue

    2015-11-01

    The potential for an interaction between lapatinib and absorption of the P-glycoprotein (ABCB1) substrate digoxin at a therapeutic dose in breast cancer patients was characterized. Seventeen women with HER2-positive metastatic breast cancer received a single oral 0.5-mg dose of digoxin on days 1 and 9 and oral lapatinib 1500 mg once daily on days 2 through 9. Digoxin pharmacokinetic parameters were determined on day 1 (digoxin administration alone) and on day 9 (coadministration of lapatinib and digoxin), and parameters were compared to determine the effects of lapatinib on digoxin absorption. Concomitant medications that could affect ABCB1 were accounted for. Lapatinib 1500 mg/day increased digoxin absorption approximately 80%, implicating lapatinib inhibition of intestinal ABCB1-mediated efflux. In summary, coadministration of lapatinib with narrow therapeutic index drugs that are substrates of ABCB1 should be undertaken with caution and dose adjustment should be considered. PMID:27137717

  18. Tunable enhanced optical absorption of graphene using plasmonic perfect absorbers

    SciTech Connect

    Cai, Yijun; Zhu, Jinfeng; Liu, Qing Huo

    2015-01-26

    Enhancement and manipulation of light absorption in graphene is a significant issue for applications of graphene-based optoelectronic devices. In order to achieve this purpose in the visible region, we demonstrate a design of a graphene optical absorber inspired by metal-dielectric-metal metamaterial for perfect absorption of electromagnetic waves. The optical absorbance ratios of single and three atomic layer graphene are enhanced up to 37.5% and 64.8%, respectively. The graphene absorber shows polarization-dependence and tolerates a wide range of incident angles. Furthermore, the peak position and bandwidth of graphene absorption spectra are tunable in a wide wavelength range through a specific structural configuration. These results imply that graphene in combination with plasmonic perfect absorbers have a promising potential for developing advanced nanophotonic devices.

  19. Dimension effect in lattice absorption of silicon carbide

    NASA Astrophysics Data System (ADS)

    Sokolov, I. A.; Ordin, S. V.

    2005-12-01

    We report high-sensitive experimental investigations of the SiC powders transmission spectra in the lattice oscillations region. For the SiC powders with the grain size of the order of the wave length the transmission minimum is shifted to the low-frequency range with respect to the transverse oscillation frequency of a single crystal ω T orresponding to phonon absorption with greater wave vectors. The decrease of the grain size leads to the shift and narrowing of the lattice absorption band to the high-frequency region. The observed change in the form and position of an absorption band corresponds to the narrowing of an optical phonon band due to decrease of the crystalline grain size, and approaching the lattice oscillation frequency to the frequency of molecular oscillations of Si-C in carbosilane owing to the surface energy contribution increase.

  20. UV-visible absorption cross sections of nitrous acid

    NASA Astrophysics Data System (ADS)

    Stutz, J.; Kim, E. S.; Platt, U.; Bruno, P.; Perrino, C.; Febo, A.

    2000-06-01

    Nitrous acid, HONO, is a source of OH radicals in the polluted atmosphere. Although the atmospheric chemistry of HONO is qualitatively understood, not much quantitative information exists. The magnitude of the OH production by HONO photolysis depends on the spectrum of its absorption cross sections; therefore the knowledge of σ'HONO(λ) is essential. The spectrum of the differential cross sections σ'HONO(λ) is needed to detect HONO in the atmosphere by differential optical absorption spectroscopy (DOAS). Here we present measurements of the HONO UV-visible absorption cross sections with a spectral resolution better than 0.1 nm and a high signal-to-noise ratio. The maximum value of the absorption cross sections is σHONO (354 nm) = (5.19±0.26) × 10-19 cm2 and agrees well with literature data. Nevertheless, calculations based on data from this work and on literature data reveal that an uncertainty of ˜15% remains for the HONO photolysis rates. The new σHONO(λ) has been employed in DOAS measurements in Milan, Italy.