Mertens, Christopher J.; Moyers, Michael F.; Walker, Steven A.; Tweed, John
2010-01-01
Recent developments in NASA s deterministic High charge (Z) and Energy TRaNsport (HZETRN) code have included lateral broadening of primary ion beams due to small-angle multiple Coulomb scattering, and coupling of the ion-nuclear scattering interactions with energy loss and straggling. This new version of HZETRN is based on Green function methods, called GRNTRN, and is suitable for modeling transport with both space environment and laboratory boundary conditions. Multiple scattering processes are a necessary extension to GRNTRN in order to accurately model ion beam experiments, to simulate the physical and biological-effective radiation dose, and to develop new methods and strategies for light ion radiation therapy. In this paper we compare GRNTRN simulations of proton lateral broadening distributions with beam measurements taken at Loma Linda University Proton Therapy Facility. The simulated and measured lateral broadening distributions are compared for a 250 MeV proton beam on aluminum, polyethylene, polystyrene, bone substitute, iron, and lead target materials. The GRNTRN results are also compared to simulations from the Monte Carlo MCNPX code for the same projectile-target combinations described above.
Theoretical Manifestation of the Broadening Effect on Photoelectron Angular Distributions
ZHANG Jing-Tao(张敬涛); ZHOU Lan(周岚); ZHANG Wen-Qi(张文琦); XU Zhi-Zhan(徐至展); GUO Dong-Sheng(郭东升); R.R.Freeman
2003-01-01
The broadening effect in photoelectron angular distributions (PADs) observed by Freeman et al. Is studied theoretically. Using a nonperturbative scattering theory developed for multiphoton ionization with the inclusion of spontaneous emission, we calculate the PADs for above-threshold ionization (ATI) peaks. The numerical calculations from our theory reproduce the kinetic-energy dependence and the laser-intensity dependence of PADs of ATI peaks observed by Freeman et al., [Phys. Rev. Lett. 57 (1986) 3156] and provide an evidence for the existence of the ponderomotive momentum of intense laser fields.
Ali, M. Al-Haj; Stroomer, J.; Betlem, B.; Weickert, G.; Roffel, B.
2008-01-01
This study presents a feasibility study of the broadening of the polypropylene molecular weight distribution produced using a multisite Ziegler-Natta catalyst in a continuous liquid-pool polymerization reactor. The broadening is achieved by operating the reactor under periodic forcing of both hydrogen and catalyst feed flows. Model-based dynamic optimization is used to determine the cycle period and peak width for these inputs. Through simulation it is shown that limited widening (similar to ...
Surface anisotropy broadening of the energy barrier distribution in magnetic nanoparticles.
Pérez, N; Guardia, P; Roca, A G; Morales, M P; Serna, C J; Iglesias, O; Bartolomé, F; García, L M; Batlle, X; Labarta, A
2008-11-26
The effect of surface anisotropy on the distribution of energy barriers in magnetic fine particles of nanometer size is discussed within the framework of the Tln(t/τ(0)) scaling approach. The comparison between the distributions of the anisotropy energy of the particle cores, calculated by multiplying the volume distribution by the core anisotropy, and of the total anisotropy energy, deduced by deriving the master curve of the magnetic relaxation with respect to the scaling variable Tln(t/τ(0)), enables the determination of the surface anisotropy as a function of the particle size. We show that the contribution of the particle surface to the total anisotropy energy can be well described by a size-independent value of the surface energy per unit area which permits the superimposition of the distributions corresponding to the particle core and effective anisotropy energies. The method is applied to a ferrofluid composed of non-interacting Fe(3-x)O(4) particles of 4.9 nm average size and x about 0.07. Even though the size distribution is quite narrow in this system, a relatively small value of the effective surface anisotropy constant K(s) = 2.9 × 10(-2) erg cm(-2) gives rise to a dramatic broadening of the total energy distribution. The reliability of the average value of the effective anisotropy constant, deduced from magnetic relaxation data, is verified by comparing it to that obtained from the analysis of the shift of the ac susceptibility peaks as a function of the frequency. PMID:21836285
Comparison of different climate regimes: the impact of broadening participation
So-far, most climate mitigation studies look at climate policy strategies in a so-called first-best world, i.e. using the least expensive emission reduction options in all world regions and sectors. To explore the impact of limited participation of countries, we have run a set of scenarios that explore the impact of introducing a carbon tax in OECD, the BRIC countries (Brazil Russia, India and China) and the rest of the world. The results show that carbon taxes can effectively reduce greenhouse gas emissions. However, if low greenhouse gas concentration levels are to be achieved, early participation (in some form) of large developing countries is important to increase reduction potential. It should be noted that global carbon taxes (without additional assumptions) lead to relatively high costs in low-income regions. Cap-and-trade regimes have more flexibility to create a comparable distribution of costs amongst countries.
Doppler broadenings of impurity (O, N and C) lines in hydrogen discharges were observed with the JFT-2 and DIVA tokamak devices for the purpose of determining the spatial distribution of the ion temperature. A 1-meter Czerny-Turner type vacuum monochromator was used in higher orders for sufficient resolution. Impurity emissions are localized in shell-like regions in the minor cross-section. The radial distribution of the ion temperature was determined from the Doppler broadening of various impurity lines and from the localization of line intensities. The Doppler temperatures of the 0+6 ion were found to be 256 eV for a 100 kA, 14 kG discharge with JFT-2 and 220 eV for a 28 KA, 20 kG discharge with DIVA. (author)
A method of X-ray line-broadening analysis is presented whereby the coherence length and microstrain contributions can be calculated using a Monte Carlo interference-function-fitting algorithm. The method is based on the 'column-like' crystal model and can be applied to both single and multiple-order reflections. Examples on simulated diffraction peaks, deformed face-centred-cubic palladium powder and heavily textured deformed body-centred-cubic low-carbon-steel sheets are presented and comparisons are made with currently applied methods. (orig.)
吴奇; 牛爱珍
1999-01-01
In dynamic laser light scattering (LLS), for a given polydisperse sample, a line-width distribution G(Γ) or the translational diffusion coefficient distribution G(D) can be obtained from the measured time correlation function. For rigid colloid particles, G(Γ) can be directly related to the hydrodynamic size distribution. However, for flexible polymer chains, G(Γ) depends not only on the chain length distribution, but also on the relaxation of the chain conformation; that is, even for a monodisperse polymer sample there still exists a chain conformation distribution. If the time scale of the chain conformation relaxation is comparable to that of the translational diffusion, such as in the case of a very long polymer chain, the conformation relaxation might lead to an additional broadening in G (Γ). This "conformation broadening" has been directly observed for the first time by comparing two G(Γ) s obtained from a poly(N-isopropyl-acrylamide) solution at～25℃ and～32℃ at which the solution is ther
Ion Dynamics Effect on Stark-Broadened Line Shapes: A Cross-Comparison of Various Models
Sandrine Ferri
2014-07-01
Full Text Available Modeling the Stark broadening of spectral lines in plasmas is a complex problem. The problem has a long history, since it plays a crucial role in the interpretation of the observed spectral lines in laboratories and astrophysical plasmas. One difficulty is the characterization of the emitter’s environment. Although several models have been proposed over the years, there have been no systematic studies of the results, until now. Here, calculations from stochastic models and numerical simulations are compared for the Atoms 2014, 2 300 Lyman-α and -β lines in neutral hydrogen. Also discussed are results from the Helium-α and -β lines of Ar XVII.
Electron impact broadening of Si IV spectral lines: Comparison with recent experiments
Electron impact widths of eight Si IV spectral lines have been calculated using our quantum mechanical method. Semiclassical perturbation calculations using atomic data from the SUPERSTRUCTURE code have been also performed. Comparison with recent measurements shows that they are always lower than our quantum mechanical, semiclassical perturbation and all other theoretical results. A disagreement in the importance of fine structure effects between our results and the measured ones has been reported here.
Distributed Wind Policy Comparison Tool
None
2011-12-01
Power through Policy: 'Best Practices' for Cost-Effective Distributed Wind is a U.S. Department of Energy (DOE)-funded project to identify distributed wind technology policy best practices and to help policymakers, utilities, advocates, and consumers examine their effectiveness using a pro forma model. Incorporating a customized feed from the Database of State Incentives for Renewables and Efficiency (DSIRE), the Web-based Distributed Wind Policy Comparison Tool (Policy Tool) is designed to assist state, local, and utility officials in understanding the financial impacts of different policy options to help reduce the cost of distributed wind technologies. The Policy Tool can be used to evaluate the ways that a variety of federal and state policies and incentives impact the economics of distributed wind (and subsequently its expected market growth). It also allows policymakers to determine the impact of policy options, addressing market challenges identified in the U.S. DOE’s '20% Wind Energy by 2030' report and helping to meet COE targets.
Lunnemann, Per; van Dijk-Moes, Relinde J A; Pietra, Francesca; Vanmaekelbergh, Daniël; Koenderink, A Femius
2013-01-01
We demonstrate that a simple silver coated ball lens can be used to accurately measure the entire distribution of radiative transition rates of quantum dot nanocrystals. This simple and cost-effective implementation of Drexhage's method that uses nanometer-controlled optical mode density variations near a mirror, not only allows to extract calibrated ensemble-averaged rates, but for the first time also to quantify the full inhomogeneous dispersion of radiative and non radiative decay rates across thousands of nanocrystals. We apply the technique to novel ultra-stable CdSe/CdS dot-in-rod emitters. The emitters are of large current interest due to their improved stability and reduced blinking. We retrieve a room-temperature ensemble average quantum efficiency of 0.87+-0.08 at a mean lifetime around 20 ns. We confirm a log-normal distribution of decay rates as often assumed in literature and we show that the rate distribution-width, that amounts to about 30% of the mean decay rate, is strongly dependent on the l...
The distribution of interlaboratory comparison data
Heydorn, Kaj
2008-01-01
The distribution of mutually consistent results from interlaboratory comparisons is expected to be leptokurtic, and readers are warned against accepting conclusions based on simulations assuming normality.......The distribution of mutually consistent results from interlaboratory comparisons is expected to be leptokurtic, and readers are warned against accepting conclusions based on simulations assuming normality....
A study is made of the effects of Doppler broadening on pure gain without inversion, which means that neither one-photon nor two-photon inversions are allowed, and non-pure gain without inversion, which means that one-photon inversion does not occur but two-photon inversion is present, in a closed Λ-type three-level system with incoherent pumping. It is shown that when the driving field is resonant but the probe field is not, in a certain range of Doppler width, for the case of the lower degree of frequency up-conversion, generally, pure gain without inversion increases monotonically and non-pure gain without inversion does not monotonically increase or decrease with increasing Doppler width; for the case of the higher degree of frequency up-conversion, pure gain without inversion decreases monotonically but non-pure gain without inversion cannot be produced. In the case of two-photon resonance, in some range of Doppler width, pure gain without inversion does not monotonically increase or decrease while non-pure gain without inversion decreases monotonically with Doppler width increasing. Finally, an experimental scheme for examining our theoretical result is given. (classical areas of phenomenology)
Novel directional comparison protection for distribution lines
2008-01-01
For quickly clearing up a fault of distribution lines, which concerned with complex structure and operating modes, a directional comparison protection is necessary. The paper evaluated the traditional directional relay through modeling a typical distribution system and presented a novel negative sequence directional relay and a new directional comparison protection scheme specially designed for distribution systems. In the relay and the protection scheme, a particular negative sequence component has been constructed to solve the problem that there is no negative sequence component in a symmetrical fault case so that they could operate correctly in both asymmetrical fault and symmetrical fault. Extensive EMTP simulation studies proved that the protection schemes are able to provide fast and reliable responses for all fault conditions. In particular, they are able to give correct responses adapting to the change of system operation conditions, including the changing of system configuration, power flow direction, and source and tapped-offload conditions.
Cohen, Marie Ramirez; Frydman, Veronica; Milko, Petr; Iron, Mark A; Abdelkader, Elwy H; Lee, Michael D; Swarbrick, James D; Raitsimring, Arnold; Otting, Gottfried; Graham, Bim; Feintuch, Akiva; Goldfarb, Daniella
2016-05-14
coupling approximation. We apply this approach to the A93C/N140C mutant of T4 lysozyme labeled with two different Gd(3+) tags that have narrow central transitions and show that even for a distance of 4 nm there is still a significant (about two-fold) broadening that is removed by increasing Δν to 636 MHz and 898 MHz. PMID:27102158
Hansen, Per Lunnemann; Rabouw, Freddy T.; van Dijk-Moes, Relinde J. A.;
2013-01-01
We demonstrate that a simple silver coated ball lens can be used to accurately measure the entire distribution of radiative transition rates of quantum dot nanocrystals. This simple and cost-effective implementation of Drexhage’s method that uses nanometer-controlled optical mode density variations...
Distributed Wind Policy Comparison Tool Guidebook
2011-11-01
Power through Policy: 'Best Practices' for Cost-Effective Distributed Wind is a U.S. Department of Energy (DOE)-funded project to identify distributed wind technology policy best practices and to help policymakers, utilities, advocates, and consumers examine their effectiveness using a pro forma model. Incorporating a customized feed from the Database of State Incentives for Renewables and Efficiency (DSIRE), the Web-based Distributed Wind Policy Comparison Tool (Policy Tool) is designed to assist state, local, and utility officials in understanding the financial impacts of different policy options to help reduce the cost of distributed wind technologies. The Policy Tool can be used to evaluate the ways that a variety of federal and state policies and incentives impact the economics of distributed wind (and subsequently its expected market growth). It also allows policymakers to determine the impact of policy options, addressing market challenges identified in the U.S. DOE's '20% Wind Energy by 2030' report and helping to meet COE targets.
ZHANG Jing-Shang
2004-01-01
In fitting the double-differential measurements thelevelwidth broadening effect should be taken into account properly due to Heisenberg uncertainty.Besides level width broadening effect the energy resolution in the measurements is also needed in this procedure.In general,the traditional normal Gaussian expansion is employed.However,the research indicates that to do so in this way the energy balance could not hold.For this reason,the deformed Gaussian expansion functions with exponential form for both the single energy point and continuous spectrum are introduced,with which the normalization and energy balance conditions could hold exactly in the analytical form.
Comparison between Different Air Distribution Systems
Nielsen, Peter V.
The aim of an air conditioning system is to remove excess heat in a room and replace room air with fresh air to obtain a high air quality. It is not sufficient to remove heat and contaminated air, it is also necessary to distribute and control the air movement in the room to create thermal comfort...... in the occupied zone. Most air distribution systems are based on mixing ventilation with ceiling or wall-mounted diffusers or on displacement ventilation with wall-mounted low velocity diffusers. New principles for room air distribution were introduced during the last decades, as the textile...... terminals mounted in the ceiling and radial diffusers with swirling flow also mounted in the ceiling. This paper addresses five air distribution systems in all, namely mixing ventilation from a wallmounted terminal, mixing ventilation from a ceiling-mounted diffuser, mixing ventilation from a ceiling...
Broadening the radiography spectrum
The text discuses the mammography in breast screening and evaluation of breast cancer; Small parts ultrasounds at plaza imaging solutions; role of a Radiographer in mammography-new perspective; Medical imaging education in africa; Caring for the paediatric patient as to broaden radiotherapy spectrum; Problems and challenges in care for children undergoing radiotherapy; Paediatric radiotherapy, management and side effects; The principles of pattern recognition of skeletal structures; the place of distance learning education in broadening the radiography spectrum; the curriculum and budgeting image; sonographer's guide; Computed radiography- X-Ray with vision; digital Radiography in Kenya today; Particle Therapy at Ithemba Labs; The role of lung perfusion and ventilation study in the evaluation of the pulmonary embolism and lastly, an overview of Head and neck treatment at Kenyatta National hospital radiotherapy
De Kertanguy, A
2015-01-01
Giving new insight for line broadening theory for atoms with more structure than hydrogen in most stars. Using symbolic software to build precise wave functions corrected for ds;dp quantum defects. The profiles obtained with that approach, have peculiar trends, narrower than hydrogen, all quantum defects used are taken from atomic database topbase. Illustration of stronger effects of ions and electrons on the alkaline profiles, than neutral-neutral collision mechanism. Keywords : Stars: fundamental parameters - Atomic processes - Line: profiles.
Comparison of sparse point distribution models
Erbou, Søren Gylling Hemmingsen; Vester-Christensen, Martin; Larsen, Rasmus;
2010-01-01
This paper compares several methods for obtaining sparse and compact point distribution models suited for data sets containing many variables. These are evaluated on a database consisting of 3D surfaces of a section of the pelvic bone obtained from CT scans of 33 porcine carcasses. The superior...
Comparison of aerosol size distribution in coastal and oceanic environments
Kusmierczyk-Michulec, J.T.; Eijk, A.M.J. van
2006-01-01
The results of applying the empirical orthogonal functions (EOF) method to decomposition and approximation of aerosol size distributions are presented. A comparison was made for two aerosol data sets, representing coastal and oceanic environments. The first data set includes measurements collected a
Stark Broadening and White Dwarfs
Dimitrijevic, Milan S; Simic, Zoran; Sahal-Brechot, Sylvie
2012-01-01
White dwarf and pre-white dwarf atmospheres are one of the best examples for the application of Stark broadening research results in astrophysics, due to plasma conditions very favorable for this line broadening mechanism. For example in hot hydrogen-deficient (pre-) white dwarf stars Teff = 75 000 K - 180 000 K and log g = 5.5-8 [cgs]. Even for much cooler DA and DB white dwarfs with typical effective temperatures of 10 000 K - 20 000 K, Stark broadening is usually the dominant broadening mechanism. In this review, Stark broadening in white dwarf spectra is considered and the attention is drawn to the STARK-B database (http://stark-b.obspm.fr/), containing Stark broadening parameters needed for white dwarf spectra analysis and synthesis, as well as to the new search facilities which will provide the collective effort to develop Virtual Atomic and Molecular Data Center (VAMDC - http://vamdc.org/).
The influence of substrate temperature and film thickness on the nanostructure of titanium (HCP) and silver (FCC) thin films deposited on glass substrates under UHV conditions by electron beam evaporation is investigated. The preferred orientation, nanostrain and stacking and twin fault probabilities in Ag and Ti films are determined as a function of film thickness and substrate temperature. A (111) preferred orientation is observed for silver films, which is dependent on both the film thickness and substrate temperature, with the highest value at a substrate temperature of 500 K. Ti/glass films showed a (002) preferred orientation. Nanostructural parameters such as the crystallite size (size of coherently diffracting domains) and nanostrain are evaluated using the Scherrer and Stocks-Wilson relations, the Williamson-Hall plot, and the single-Voigt (SV), double-Voigt (DV) and Warren-Averbach (WA) methods. Analysis of the results obtained using these methods showed that the most suitable approaches to x-ray diffraction line broadening analysis, applicable to both FCC and HCP polycrystalline thin film structures, are SV, DV and WA. The results show that the crystallite sizes increase with substrate temperature and film thickness, while the nanostrain and lattice constants decrease with thickness. The crystallite size distribution function was obtained from the size broadened part of the DV function, and the results show a shift in the maximum to larger sizes with increasing temperature and thickness
A comparison of queueing, cluster and distributed computing systems
Kaplan, Joseph A.; Nelson, Michael L.
1993-01-01
Using workstation clusters for distributed computing has become popular with the proliferation of inexpensive, powerful workstations. Workstation clusters offer both a cost effective alternative to batch processing and an easy entry into parallel computing. However, a number of workstations on a network does not constitute a cluster. Cluster management software is necessary to harness the collective computing power. A variety of cluster management and queuing systems are compared: Distributed Queueing Systems (DQS), Condor, Load Leveler, Load Balancer, Load Sharing Facility (LSF - formerly Utopia), Distributed Job Manager (DJM), Computing in Distributed Networked Environments (CODINE), and NQS/Exec. The systems differ in their design philosophy and implementation. Based on published reports on the different systems and conversations with the system's developers and vendors, a comparison of the systems are made on the integral issues of clustered computing.
Fission meter and neutron detection using poisson distribution comparison
Rowland, Mark S; Snyderman, Neal J
2014-11-18
A neutron detector system and method for discriminating fissile material from non-fissile material wherein a digital data acquisition unit collects data at high rate, and in real-time processes large volumes of data directly into information that a first responder can use to discriminate materials. The system comprises counting neutrons from the unknown source and detecting excess grouped neutrons to identify fission in the unknown source. Comparison of the observed neutron count distribution with a Poisson distribution is performed to distinguish fissile material from non-fissile material.
Comparison of aerosol size distribution in coastal and oceanic environments
Kusmierczyk-Michulec, J.T.; Eijk, A.M.J. van
2006-01-01
The results of applying the empirical orthogonal functions (EOF) method to decomposition and approximation of aerosol size distributions are presented. A comparison was made for two aerosol data sets, representing coastal and oceanic environments. The first data set includes measurements collected at the Irish Atlantic coast in 1994 and 1995, the second one data collected during the Rough Evaporation Duct (RED) experiment that took place off Oahu, Hawaii in 2001. The main finding is that aero...
Tran, H., E-mail: ha.tran@lisa.u-pec.fr [Laboratoire Interuniversitaire des Systèmes Atmosphériques, UMR CNRS 7583, Université Paris Est Créteil, Université Paris Diderot, Institut Pierre-Simon Laplace, 94010 Créteil Cedex (France); Domenech, J.-L. [Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Cientificas, (IEM-CSIC), Serrano 123, 28006 Madrid (Spain)
2014-08-14
Spectral shapes of isolated lines of HCl perturbed by Ar are investigated for the first time using classical molecular dynamics simulations (CMDS). Using reliable intermolecular potentials taken from the literature, these CMDS provide the time evolution of the auto-correlation function of the dipole moment, whose Fourier-Laplace transform leads to the absorption spectrum. In order to test these calculations, room temperature spectra of various lines in the fundamental band of HCl diluted in Ar are measured, in a large pressure range, with a difference-frequency laser spectrometer. Comparisons between measured and calculated spectra show that the CMDS are able to predict the large Dicke narrowing effect on the shape of HCl lines and to satisfactorily reproduce the shapes of HCl spectra at different pressures and for various rotational quantum numbers.
Thibault, F.; Mantz, A. W.; Claveau, C.; Valentin, A.; Hurtmans, D.
2007-01-01
We present measurements of He-broadening parameters for the R(0) and O(2) lines in the fundamental band of 13CO at different temperatures between 12K and room temperature. The broadening parameters are determined, taking into account confinement narrowing, by simultaneous least-squares fitting of spectra recorded using a frequency stabilized diode laser spectrometer. The pressure broadening cross sections are deduced and compared to close-coupling calculations and earlier results obtained for rotational transitions of 12 CO.
The dependence of inhomogeneous vibrational linewidth broadening on attractive forces form slowly varying local liquid number densities is examined. The recently developed Schweizer--Chandler theory of vibrational dephasing is used to compute absolute inhomogeneous broadening linewidths. The computed linewidths are compared to measured inhomogeneous broadening linewidths determined using picosecond vibrational dephasing experiments. There is a similarity between correlations of the Schweizer--Chandler and George--Auweter--Harris predicted inhomogeneous broadening linewidths and the measured inhomogeneous broadening linewidths. For the methyl stretches under investigation, this correspondence suggests that the width of the number density distribution in the liquid determines the relative inhomogeneous broadening magnitudes
Broadening nanotechnology's impact on development
Beumer, Koen
2016-05-01
Discussions about nanotechnology and development focus on applications that directly address the needs of the world's poor. Nanotechnology can certainly make an impact in the fight against global poverty, but we need to broaden our imagination.
Wind Power Forecasting Error Distributions: An International Comparison; Preprint
Hodge, B. M.; Lew, D.; Milligan, M.; Holttinen, H.; Sillanpaa, S.; Gomez-Lazaro, E.; Scharff, R.; Soder, L.; Larsen, X. G.; Giebel, G.; Flynn, D.; Dobschinski, J.
2012-09-01
Wind power forecasting is expected to be an important enabler for greater penetration of wind power into electricity systems. Because no wind forecasting system is perfect, a thorough understanding of the errors that do occur can be critical to system operation functions, such as the setting of operating reserve levels. This paper provides an international comparison of the distribution of wind power forecasting errors from operational systems, based on real forecast data. The paper concludes with an assessment of similarities and differences between the errors observed in different locations.
How can model comparison help improving species distribution models?
Emmanuel Stephan Gritti
Full Text Available Today, more than ever, robust projections of potential species range shifts are needed to anticipate and mitigate the impacts of climate change on biodiversity and ecosystem services. Such projections are so far provided almost exclusively by correlative species distribution models (correlative SDMs. However, concerns regarding the reliability of their predictive power are growing and several authors call for the development of process-based SDMs. Still, each of these methods presents strengths and weakness which have to be estimated if they are to be reliably used by decision makers. In this study we compare projections of three different SDMs (STASH, LPJ and PHENOFIT that lie in the continuum between correlative models and process-based models for the current distribution of three major European tree species, Fagussylvatica L., Quercusrobur L. and Pinussylvestris L. We compare the consistency of the model simulations using an innovative comparison map profile method, integrating local and multi-scale comparisons. The three models simulate relatively accurately the current distribution of the three species. The process-based model performs almost as well as the correlative model, although parameters of the former are not fitted to the observed species distributions. According to our simulations, species range limits are triggered, at the European scale, by establishment and survival through processes primarily related to phenology and resistance to abiotic stress rather than to growth efficiency. The accuracy of projections of the hybrid and process-based model could however be improved by integrating a more realistic representation of the species resistance to water stress for instance, advocating for pursuing efforts to understand and formulate explicitly the impact of climatic conditions and variations on these processes.
Medium Induced Transverse Momentum Broadening in Hard Processes
Mueller, A H; Xiao, Bo-Wen; Yuan, Feng
2016-01-01
Using deep inelastic scattering on a large nucleus as an example, we consider the transverse momentum broadening of partons in hard processes in the presence of medium. We find that one can factorize the vacuum radiation contribution and medium related $P_T$ broadening effects into the Sudakov factor and medium dependent distributions, respectively. Our derivations can be generalized to other hard processes, such as dijet productions, which can be used as a probe to measure the medium $P_T$ broadening effects in heavy ion collisions when Sudakov effects are not overwhelming.
Comparison of aerosol size distribution in coastal and oceanic environments
Kusmierczyk-Michulec, Jolanta; van Eijk, Alexander M.
2006-08-01
The results of applying the empirical orthogonal functions (EOF) method to decomposition and approximation of aerosol size distributions are presented. A comparison was made for two aerosol data sets, representing coastal and oceanic environments. The first data set includes measurements collected at the Irish Atlantic coast in 1994 and 1995, the second one data collected during the Rough Evaporation Duct (RED) experiment that took place off Oahu, Hawaii in 2001. The main finding is that aerosol size distributions can be represented by a superposition of the mean size distribution and the first eigenvector multiplied by an amplitude function. For the two aerosol data sets the mean size distribution is very similar in the range of small particles sizes (radius 1μm). It is also reflected by the spectral shape of the eigenvector. The differences can be related to the type of aerosols present at both locations, and the amplitude function can be associated to meteorological conditions. The amplitude function also indicates the episodes with the maximum/minimum continental influence. The results of this analysis will be used in upgrades of the ANAM model.
Marshall, C. J.; Marshall, P. W.; Howe, C. L.; Reed, R. A.; Weller, R. A.; Mendenhall, M.; Waczynski, A.; Ladbury, R.; Jordan, T. M.
2007-01-01
This paper presents a combined Monte Carlo and analytic approach to the calculation of the pixel-to-pixel distribution of proton-induced damage in a HgCdTe sensor array and compares the results to measured dark current distributions after damage by 63 MeV protons. The moments of the Coulombic, nuclear elastic and nuclear inelastic damage distributions were extracted from Monte Carlo simulations and combined to form a damage distribution using the analytic techniques first described in [1]. The calculations show that the high energy recoils from the nuclear inelastic reactions (calculated using the Monte Carlo code MCNPX [2]) produce a pronounced skewing of the damage energy distribution. While the nuclear elastic component (also calculated using the MCNPX) contributes only a small fraction of the total nonionizing damage energy, its inclusion in the shape of the damage across the array is significant. The Coulombic contribution was calculated using MRED [3-5], a Geant4 [4,6] application. The comparison with the dark current distribution strongly suggests that mechanisms which are not linearly correlated with nonionizing damage produced according to collision kinematics are responsible for the observed dark current increases. This has important implications for the process of predicting the on-orbit dark current response of the HgCdTe sensor array.
In this work, Complex Robert-Bonamy calculations of half-widths and line shifts were done for N2-broadening of water for 1639 transitions in the rotational band using two models for the trajectories. The first is a model correct to second order in time, the Robert-Bonamy parabolic approximation. The second is the solution of Hamilton's equations. Both models use the isotropic part of the atom-atom potential to determine the trajectories. The present calculations used an intermolecular potential expanded to 20th order to assure the convergence of the half-widths and line shifts. The aim of the study is to assess if the difference in the half-widths and line shifts determined from the two trajectory models is greater than the accuracy requirements of the spectroscopic and remote sensing communities. The results of the calculations are compared with measurements of the half-widths and line shifts. It is shown that the effects of the trajectory model greatly exceed the needs of current remote sensing measurements and that line shape parameters calculated using trajectories determined by solving Hamilton's equations agree better with measurement.
Systematic comparison of trip distribution laws and models
Lenormand, Maxime; Ramasco, José J
2016-01-01
Trip distribution laws are basic for the travel demand characterization needed in transport and urban planning. Several approaches have been considered in the last years. One of them is the so-called gravity law, in which the number of trips is assumed to be related to the population at origin and destination and to decrease with the distance. The mathematical expression of this law resembles Newton's law of gravity, which explains its name. Another popular approach is inspired by the theory of intervening opportunities and it has been concreted into the so-called radiation models. Individuals are supposed to travel until they find a job opportunity, so the population and jobs spatial distributions naturally lead to a trip flow network. In this paper, we perform a thorough comparison between the gravity and the radiation approaches in their ability at estimating commuting flows. We test the gravity and the radiation laws against empirical trip data at different scales and coming from different countries. Diff...
A detailed treatment of the relationship between the dispersive growth kinetics of the zero-phonon hole (ZPH) of an impurity molecule in an amorphous host and burn fluence broadening of the ZPH is presented. Focus is on non-photochemical hole burning (NPHB). The equation used for simulations accounts for dispersion due to a distribution of tunneling parameters (λ-distribution), the angle between the laser polarization and the transition dipole (α-distribution), and off-resonant absorption of the zero-phonon line (ω-distribution). Two cases are considered: burned laser linewidth narrow relative to the homogeneous width of the zero-phonon line; and the reverse situation. Results are presented for two model systems whose parameter values are similar to those of aluminum phthalocyanine tetrasulphonate (APT) in hyperquenched glassy water and in hyperquenched glassy ethanol. For comparison, results are presented for the case where the hole growth kinetics are non-dispersive (single-exponential). It is found that at the early stage of burning fluence broadening is considerably more severe for a dispersive system than for a non-dispersive system. A straightforward explanation for this is given. The results are compared with those of earlier works on dispersive hole growth kinetics and fluence broadening. The results reveal the types of experiment needed to understand the aforementioned relationship, a requirement for determination of the homogeneous width of the ZPH that reflects the dynamics of the system
Methods for spatial pattern comparison in distributed hydrological modelling : [Poster
Kuhnert, Matthias; Güntner, Andreas; Klann, Mechthild; F. Martin Garrido; Zillgens, Birgit
2006-01-01
The rigorous development, application and validation of distributed hydrological models obligates to evaluate data in a spatially distributed way. In particular, spatial model predictions such as the distribution of soil moisture, runoff generating areas or nutrient-contributing areas or erosion rates, are to be assessed against spatially distributed observations. Also model inputs, such as the distribution of modelling units derived by GIS and remote sensing analyses, should be evaluated aga...
Coherent Forward Broadening in Cold Atom Clouds
Sutherland, R T
2015-01-01
It is shown that homogeneous line-broadening in a diffuse cold atom cloud is proportional to the resonant optical depth of the cloud. Further, it is demonstrated how the strong directionality of the coherent interactions causes the cloud's spectra to depend strongly on its shape, even when the cloud is held at constant densities. These two numerical observations can be predicted analytically by extending the single photon wave-function model. Lastly, elongating a cloud along the line of laser propagation causes the excitation probability distribution to deviate from the exponential decay predicted by the Beer-Lambert law to the extent where the atoms in the back of the cloud are more excited than the atoms in the front. These calculations are conducted at low densities relevant to recent experiments.
Coherent forward broadening in cold atom clouds
Sutherland, R. T.; Robicheaux, F.
2016-02-01
It is shown that homogeneous line-broadening in a diffuse cold atom cloud is proportional to the resonant optical depth of the cloud. Furthermore, it is demonstrated how the strong directionality of the coherent interactions causes the cloud's spectra to depend strongly on its shape, even when the cloud is held at constant densities. These two numerical observations can be predicted analytically by extending the single-photon wave-function model. Lastly, elongating a cloud along the line of laser propagation causes the excitation probability distribution to deviate from the exponential decay predicted by the Beer-Lambert law to the extent where the atoms at the back of the cloud are more excited than the atoms at the front. These calculations are conducted at the low densities relevant to recent experiments.
Combustion technology overview. [the use of broadened property aircraft fuels
Niedzwiecki, R. W.
1980-01-01
An overview of combustor technology developments required for use of broadened property fuels in jet aircraft is presented. The intent of current investigations is to determine the extent to which fuel properties can be varied, to obtain a data base of combustion - fuel quality effects, and to determine the trade-offs associated with broadened property fuels. Subcomponents of in-service combustors such as fuel injectors and liners, as well as air distributions and stoichiometry, are being altered to determine the extent to which fuel flexibility can be extended. Finally, very advanced technology consisting of new combustor concepts is being evolved to optimize the fuel flexibility of gas turbine combustors.
Analytical expressions for the shape and width of the lasing spectra of a quantum-dot (QD) laser in the case of a small (in comparison with the spectrum width) homogeneous broadening of the QD energy levels have been obtained. It is shown that the dependence of the lasing spectrum width on the output power at room temperature is determined by two dimensionless parameters: the width of QD distribution over the optical-transition energy, normalized to temperature, and the ratio of the optical loss to the maximum gain. The optimal dimensions of the laser active region have been found to obtain a specified width of the emission spectrum at a minimum pump current. The possibility of using multilayer structures with QDs to increase the lasing spectrum’s width has been analyzed. It is shown that the use of several arrays of QDs with deliberately variable optical-transition energies leads to broadening of the lasing spectra; some numerical estimates are presented.
Income Distribution Determinants and Inequality – International Comparison
Marinko Škare
2014-08-01
Full Text Available This study shows the relationship between income distribution and other relevant economic variables and their impact on income distribution. Panel data analysis is used to study 200 world economies and identify main income determinants. Using such a large panel to study income distribution and inequality of household income make empirical results of this study significant. Paper results show there is a large discrepancy of income distribution measured by household consumption for different classes (income deciles. Inflation, unemployment, export, labour force, population and unemployment however are the main determinants between income distribution dynamics according to the result of this study.
Comparison of piezoelectronic networks acting as distributed vibration absorbers
Maurini, Corrado; Dell'Isola, Francesco; Del Vescovo, Dionisio
2004-01-01
International audience Electric vibration absorbers made of distributed piezoelectric devices for the control of beam vibrations are studied. The absorbers are obtained by interconnecting an array of piezoelectric transducers uniformly distributed on a beam with different modular electric networks. Five different topologies are considered and their damping performance is analysed and compared.
Bourrely, Claude; Buccella, Franco; Soffer, Jacques
2008-01-01
In the framework of the statistical model for parton distributions and fragmentations functions we present a comparison of the model with a large set of unpolarized and polarized experimental data, the agreement with data supports our approach.
Analysis and Comparison of Typical Models within Distribution Network Design
Jørgensen, Hans Jacob; Larsen, Allan; Madsen, Oli B.G.
Efficient and cost effective transportation and logistics plays a vital role in the supply chains of the modern world’s manufacturers. Global distribution of goods is a very complicated matter as it involves many different distinct planning problems. The focus of this presentation is to demonstrate...... a number of important issues which have been identified when addressing the Distribution Network Design problem from a modelling angle. More specifically, we present an analysis of the research which has been performed in utilizing operational research in developing and optimising distribution...
Current phase comparison pilot scheme for distributed generation networks protection
Highlights: → An effective zone protection for DG networks is proposed based on current phase jump with fault inception. → High penetration of DG to distribution networks will represent a source of error for conventional overcurrent and distance protections schemes. → The proposed algorithm operates independently of short circuit current magnitudes variation due to penetration of DG. → This algorithm has been tested varying fault location along a DG network modeled with PV solar installation and wind farms. -- Abstract: The trends of the actual distribution networks are moving toward a high penetration of distributed generation and power electronics converters. These technologies modify contribution-to-fault current magnitudes and raise concern about new protection parameters settings to accurately detect faults on distribution networks. This paper proposes a differential phase jump pilot scheme to detect faulted branches in distribution networks. The aim of the proposed scheme is to provide an efficient algorithm with functions of fault detection and isolation, which are part of the self-healing functions used for smart grids. The proposed scheme is based on the current phase jump measured in each node with fault inception. Then, by comparing the phase jump obtained with the prefault conditions and rate changes, it determines the fault direction enabling a trip signal to the corresponding nodes to isolate the branch under fault. A distribution network has been modeled in PSCAD/EMTDC program to verify the proposed algorithm, taking into account distributed generation provided by both wind turbines (doubly fed induction generator and permanent magnet generator with full converter) and solar photovoltaic installations. The behavior of the current phase jump has been studied for both generation and load nodes. This algorithm is not affected by the magnitude of current and voltage and has been tested varying fault location and resistance along the modeled
On the Fly Doppler Broadening Using Multipole Representation
On the Fly Doppler broadening is the technique to avoid pre-generation of the microscopic cross section, in other words, reduce the amount of storage. Currently, there are different types of formalisms used by NJOY code to generate reaction cross section and accomplish its Doppler broadening. Single-Level Breit-Wigner (SLBW) formalism is limited to well-separated resonances, in other words, it does not consider interference between energy levels. Multi-Level Breit- Wigner formalism (MLBW) was tested as the candidate for the cross section generation in the Monte Carlo code, which is under development in UNIST. According to the results, MLBW method requires huge amount of computational time to produce cross section at certain energy point. Reich-Moore (RM) technique can generate only 0K cross section, which means that it cannot produce broaden cross section directly from resonance parameters. The first step was to convert resonance parameters given in nuclear data file into multipoles. MPR shows very high potential to be used as the formalism in the on-the-fly Doppler broadening module of MCS. One of the main reasons is that comparison of the time cost shown in Table IV supports application of multipole representation
Implementing Distributed Operations: A Comparison of Two Deep Space Missions
Mishkin, Andrew; Larsen, Barbara
2006-01-01
Two very different deep space exploration missions--Mars Exploration Rover and Cassini--have made use of distributed operations for their science teams. In the case of MER, the distributed operations capability was implemented only after the prime mission was completed, as the rovers continued to operate well in excess of their expected mission lifetimes; Cassini, designed for a mission of more than ten years, had planned for distributed operations from its inception. The rapid command turnaround timeline of MER, as well as many of the operations features implemented to support it, have proven to be conducive to distributed operations. These features include: a single science team leader during the tactical operations timeline, highly integrated science and engineering teams, processes and file structures designed to permit multiple team members to work in parallel to deliver sequencing products, web-based spacecraft status and planning reports for team-wide access, and near-elimination of paper products from the operations process. Additionally, MER has benefited from the initial co-location of its entire operations team, and from having a single Principal Investigator, while Cassini operations have had to reconcile multiple science teams distributed from before launch. Cassini has faced greater challenges in implementing effective distributed operations. Because extensive early planning is required to capture science opportunities on its tour and because sequence development takes significantly longer than sequence execution, multiple teams are contributing to multiple sequences concurrently. The complexity of integrating inputs from multiple teams is exacerbated by spacecraft operability issues and resource contention among the teams, each of which has their own Principal Investigator. Finally, much of the technology that MER has exploited to facilitate distributed operations was not available when the Cassini ground system was designed, although later adoption
Causes of EIT Intensity Correlation Power Broadening
Zheng, Aojie; Crescimanno, Michael; O'Leary, Shannon
2015-01-01
EIT noise correlation spectroscopy holds promise as a simple, robust method for performing high resolution spectroscopy used in optical magnetometry and clocks. Of relevance to these applications, we report here on a measurement of and a theory model for power broadening of EIT noise correlation resonances. Taken together they identify physical antecedents of noise correlation power broadening.
Stark broadening data for stellar plasma research.
Dimitrijević, M. S.
Results of an effort to provide to astrophysicists and physicists an as much as possible complete set of Stark broadening parameters needed for stellar opacity calculations, stellar atmosphere modelling, abundance determinations and diagnostics of different plasmas in astrophysics, physics and plasma technology, are presented. Stark broadening has been considered within the semiclassical perturbation, and the modified semiempirical approaches.
Stark broadening of B IV spectral lines
Dimitrijević, Milan S.; Christova, Magdalena; Simić, Zoran; Kovačević, Andjelka; Sahal-Bréchot, Sylvie
2016-08-01
Stark broadening parameters for 157 multiplets of helium-like boron (B IV) have been calculated using the impact semiclassical perturbation formalism. Obtained results have been used to investigate the regularities within spectral series. An example of the influence of Stark broadening on B IV lines in DO white dwarfs is given.
Stark broadening of B IV spectral lines
Dimitrijevic, Milan S; Simic, Zoran; Kovacevic, Andjelka; Sahal-Brechot, Sylvie
2016-01-01
Stark broadening parameters for 157 multiplets of helium like boron (B IV) have been calculated using the impact semiclassical perturbation formalism. Obtained results have been used to investigate the regularities within spectral series. An example of the influence of Stark broadening on B IV lines in DO white dwarfs is given.
A comparison of graphical design techniques for parallel, distributed software
M. Polman; M.R. van Steen
1994-01-01
textabstractWe have compared three graphical design techniques, OMT, ADL, and PARSE, on their suitability for the development of parallel/distributed applications. Our method has been to use all three of them in modeling one, existing, application: a backup facility running within the Andrew File Sy
Systematic comparison of trip distribution laws and models
Lenormand, Maxime; Bassolas, Aleix; Ramasco, José J.
2015-01-01
Trip distribution laws are basic for the travel demand characterization needed in transport and urban planning. Several approaches have been considered in the last years. One of them is the so-called gravity law, in which the number of trips is assumed to be related to the population at origin and destination and to decrease with the distance. The mathematical expression of this law resembles Newton's law of gravity, which explains its name. Another popular approach is inspired by the theory ...
Systematic comparison of trip distribution laws and models
Lenormand, Maxime; Bassolas, Aleix; José J. Ramasco
2016-01-01
Trip distribution laws are basic for the travel demand characterization needed in transport and urban planning. Several approaches have been considered in the last years. One of them is the so-called gravity law, in which the number of trips is assumed to be related to the population at origin and destination and to decrease with the distance. The mathematical expression of this law resembles Newton's law of gravity, which explains its name. Another popular approach is inspired by the theory ...
Secure distributed genome analysis for GWAS and sequence comparison computation
Zhang, Yihua; Blanton, Marina; Almashaqbeh, Ghada
2015-01-01
Background The rapid increase in the availability and volume of genomic data makes significant advances in biomedical research possible, but sharing of genomic data poses challenges due to the highly sensitive nature of such data. To address the challenges, a competition for secure distributed processing of genomic data was organized by the iDASH research center. Methods In this work we propose techniques for securing computation with real-life genomic data for minor allele frequency and chi-...
A comparison of graphical design techniques for parallel, distributed software
Polman, M.; Steen, M.R.
1994-01-01
textabstractWe have compared three graphical design techniques, OMT, ADL, and PARSE, on their suitability for the development of parallel/distributed applications. Our method has been to use all three of them in modeling one, existing, application: a backup facility running within the Andrew File System. We compare and analyze the outcomes on a number of important design aspects. Based on this, we draw conclusions on each individual technique and on graphical design techniques for parallel/di...
Comparison of the charge distributions of the titanium isotopes
Measurements have been made of the elastic electron scattering from the three even isotopes of titanium, Ti46, Ti48, and Ti50, with the objective of determining the differences in their ground state charge distributions. The experiment measures the ratios of the elastic cross sections of the three isotopes, thereby eliminating many of the uncertainties peculiar to an absolute cross section measurement. The experiment was done at the NBS Linac in Gaithersburg, Maryland. Theoretical calculations using a partial wave elastic scattering program, showed that the ratios of cross sections arising from scattering from two slightly different Fermi type 2 parameter charge distributions, depended strongly on the differences in the parameter describing the charge distribution, but only weakly on the actual values of these parameters. These ratio curves, considered as a function of momentum transfer, achieved their extreme values at momenta transfer near 1.0 F-1, which is near the point where the Born approximation form factor goes to zero. Therefore, ratios of cross sections were measured at momenta transfer ranging from .55 to 1.1 F-1; by holding the scattering angle fixed at 127.50 and varying the incident beam energy from 60 to 123 MeV. 43 refs., 45 figs., 9 tabs
A Comparison of Generalized Hyperbolic Distribution Models for Equity Returns
Virginie Konlack Socgnia
2014-01-01
Full Text Available We discuss the calibration of the univariate and multivariate generalized hyperbolic distributions, as well as their hyperbolic, variance gamma, normal inverse Gaussian, and skew Student’s t-distribution subclasses for the daily log-returns of seven of the most liquid mining stocks listed on the Johannesburg Stocks Exchange. To estimate the model parameters from historic distributions, we use an expectation maximization based algorithm for the univariate case and a multicycle expectation conditional maximization estimation algorithm for the multivariate case. We assess the goodness of fit statistics using the log-likelihood, the Akaike information criterion, and the Kolmogorov-Smirnov distance. Finally, we inspect the temporal stability of parameters and note implications as criteria for distinguishing between models. To better understand the dependence structure of the stocks, we fit the MGHD and subclasses to both the stock returns and the two leading principal components derived from the price data. While the MGHD could fit both data subsets, we observed that the multivariate normality of the stock return residuals, computed by removing shared components, suggests that the departure from normality can be explained by the structure in the common factors.
Momentum broadening in unstable quark-gluon plasma
Carrington, M. E.; Mrówczyński, St.; Schenke, B.
2016-01-01
Quark-gluon plasma produced at the early stage of ultrarelativistic heavy ion collisions is unstable, if weakly coupled, due to the anisotropy of its momentum distribution. Chromomagnetic fields are spontaneously generated and can reach magnitudes much exceeding typical values of the fields in equilibrated plasma. We consider a high energy test parton traversing an unstable plasma that is populated with strong fields. We study the momentum broadening parameter $\\hat q$ which determines the ra...
On the process dependent nuclear $k_\\perp$ broadening effect
Schäfer, Andreas; Zhou, Jian
2013-01-01
We study the process dependent nuclear $k_\\perp$ broadening effect by employing the transverse momentum dependent(TMD) factorization approach in combination with the Mclerran-Venugopalan(MV) model. More specifically, we investigate how the parton transverse momentum distributions are affected by the process dependent gauge links in cold nuclear matter. In particular, our analysis also applies to the polarized cases including the nuclear quark Boer-Mulders function and the linearly polarized g...
The multiplicity distributions of charged hadrons produced in the deep inelastic muon-proton scattering at 280 GeV are analysed in various rapidity intervals, as a function of the total hadronic centre of mass energy W ranging from 4-20 GeV. Multiplicity distributions for the backward and forward hemispheres are also analysed separately. The data can be well parameterized by binomial distributions, extending their range of applicability to the case of lepton-proton scattering. The energy and the rapidity dependence of the parameters is presented and a smooth transition from the binomial distribution via Poissonian to the ordinary binomial is observed. (orig.)
Comparison modeling for alpine vegetation distribution in an arid area.
Zhou, Jihua; Lai, Liming; Guan, Tianyu; Cai, Wetao; Gao, Nannan; Zhang, Xiaolong; Yang, Dawen; Cong, Zhentao; Zheng, Yuanrun
2016-07-01
Mapping and modeling vegetation distribution are fundamental topics in vegetation ecology. With the rise of powerful new statistical techniques and GIS tools, the development of predictive vegetation distribution models has increased rapidly. However, modeling alpine vegetation with high accuracy in arid areas is still a challenge because of the complexity and heterogeneity of the environment. Here, we used a set of 70 variables from ASTER GDEM, WorldClim, and Landsat-8 OLI (land surface albedo and spectral vegetation indices) data with decision tree (DT), maximum likelihood classification (MLC), and random forest (RF) models to discriminate the eight vegetation groups and 19 vegetation formations in the upper reaches of the Heihe River Basin in the Qilian Mountains, northwest China. The combination of variables clearly discriminated vegetation groups but failed to discriminate vegetation formations. Different variable combinations performed differently in each type of model, but the most consistently important parameter in alpine vegetation modeling was elevation. The best RF model was more accurate for vegetation modeling compared with the DT and MLC models for this alpine region, with an overall accuracy of 75 % and a kappa coefficient of 0.64 verified against field point data and an overall accuracy of 65 % and a kappa of 0.52 verified against vegetation map data. The accuracy of regional vegetation modeling differed depending on the variable combinations and models, resulting in different classifications for specific vegetation groups. PMID:27307276
A Comparison of Distribution Free and Non-Distribution Free Factor Analysis Methods
Ritter, Nicola L.
2012-01-01
Many researchers recognize that factor analysis can be conducted on both correlation matrices and variance-covariance matrices. Although most researchers extract factors from non-distribution free or parametric methods, researchers can also extract factors from distribution free or non-parametric methods. The nature of the data dictates the method…
Comparison of options for distributed generation in India
There is renewed interest in distributed generation (DG). This paper reviews the different technological options available for DG, their current status and evaluates them based on the cost of generation and future potential in India. The non-renewable options considered are internal combustion engines fuelled by diesel, natural gas and microturbines and fuel cells fired by natural gas. The renewable technologies considered are wind, solar photovoltaic, biomass gasification and bagasse cogeneration. The cost of generation is dependent on the load factor and the discount rate. Gas engines and Bagasse based cogeneration are found to be the most cost effective DG options while wind and biomass gasifier fired engines are viable under certain conditions. PEM Fuel cells and micro turbines based on natural gas need a few demonstrations projects and cost reductions before becoming viable. A strategy involving pilot projects, tracking of costs and dissemination of information is likely to result in DG meeting 10% of India's power needs by 2012
Dipole-dipole broadening of Rb ns-np microwave transitions
The dipole-dipole broadening of ns-np microwave transitions of cold Rb Rydberg atoms in a magneto-optical trap has been recorded for 28≤n≤51. Since the electric dipole transition matrix elements scale as n2, a broadening rate scaling as n4 is expected and a broadening rate of 8.2x10-15n4 MHz cm3 is observed. The observed broadening is smaller than expected from a classical picture due to the spin-orbit interaction in the np atoms. The broadened resonances are asymmetric and cusp shaped, and their line shapes can be reproduced by a diatomic model which takes into account the dipole-dipole interaction, including the spin-orbit interaction, the strengths of the allowed microwave transitions, and the distribution of the atomic spacings in the trap.
Comparison of TCP automatic tuning techniques for distributed computing
Weigle, E. H. (Eric H.); Feng, W. C. (Wu-Chun)
2002-01-01
Rather than painful, manual, static, per-connection optimization of TCP buffer sizes simply to achieve acceptable performance for distributed applications, many researchers have proposed techniques to perform this tuning automatically. This paper first discusses the relative merits of the various approaches in theory, and then provides substantial experimental data concerning two competing implementations - the buffer autotuning already present in Linux 2.4.x and 'Dynamic Right-Sizing.' This paper reveals heretofore unknown aspects of the problem and current solutions, provides insight into the proper approach for various circumstances, and points toward ways to further improve performance. TCP, for good or ill, is the only protocol widely available for reliable end-to-end congestion-controlled network communication, and thus it is the one used for almost all distributed computing. Unfortunately, TCP was not designed with high-performance computing in mind - its original design decisions focused on long-term fairness first, with performance a distant second. Thus users must often perform tortuous manual optimizations simply to achieve acceptable behavior. The most important and often most difficult task is determining and setting appropriate buffer sizes. Because of this, at least six ways of automatically setting these sizes have been proposed. In this paper, we compare and contrast these tuning methods. First we explain each method, followed by an in-depth discussion of their features. Next we discuss the experiments to fully characterize two particularly interesting methods (Linux 2.4 autotuning and Dynamic Right-Sizing). We conclude with results and possible improvements.
Comparison between distributed and centralized demand assignment TDMA satellite access schemes
Celandroni, Nedo; Ferro, Erina; Potort?, Francesco
1996-01-01
This paper presents the performance measurements from a comparison between FODAIIBEA and two other satellite access schemes, FEEDERS and DRIFS. The three schemes differ in terms of the scheduling of the channel capacity: Le. centralized control in FODA/IBEA and distributed in the other two. All these access schemes were designed at CNUCE, where the simulation tool used for the comparison was also developed. FODA/IBEA was developed and tested on several satellites (Olympus, Eutelsat and Italsa...
Performance Comparison of QOS Metrics for a Distributed Pricing Scheme
S.S. Prasad
2011-06-01
Full Text Available De-centralized nature of nodes, in ad-hoc networks, results in the users adapting their operations independently. Such operations are mostly biased up on the figures and data available for the parameter s which are imperative for superior performance or, i n other words, improved Quality of Performance (QoS of the nodes. In centrally controlled networks foll owing cooperative game theory principles, collectiv e operations are performed by the nodes for better Qo S of the network. Although nodes in decentralized networks undertake individual operations, the final outcome of the whole network and thus the performa nce of the nodes in the network are influenced by the o perations of other nodes. Hence, a distributed reso urce allocation approach in such a scenario can be model ed as a non-cooperative game. Asynchronous Distributed Pricing (ADP is one such virtual prici ng algorithm in which a user’s payoff is determined by the difference between how much a given performance metric is valued and how much is paid for it. User service demands and priorities are modeled using nu merically emulated QoS metrics termed as utility functions. The network objective is to maximize the sum of all users’ payoff. However, for convergence of the sum of all users’ payoff to a global maximum, t he determination of the QoS metric’s utility functi on with sufficient concavity is essential. Although su permodularity conditions have been previously defin ed and determined to obtain suitable utility functions , we have numerically and analytically illustrated that the convergence performance characteristics fluctuates with the choice of QoS metrics in the algorithm for similar utility functions as well. We have assessed the optimality of utility functions under Signal-t o- Interference-plus-Noise ratio and Signal-to-Interfe rence ratio based calculations. This paper also exp lores into the difference in performance characteristics obtained by the addition of a
Secure distributed genome analysis for GWAS and sequence comparison computation
2015-01-01
Background The rapid increase in the availability and volume of genomic data makes significant advances in biomedical research possible, but sharing of genomic data poses challenges due to the highly sensitive nature of such data. To address the challenges, a competition for secure distributed processing of genomic data was organized by the iDASH research center. Methods In this work we propose techniques for securing computation with real-life genomic data for minor allele frequency and chi-squared statistics computation, as well as distance computation between two genomic sequences, as specified by the iDASH competition tasks. We put forward novel optimizations, including a generalization of a version of mergesort, which might be of independent interest. Results We provide implementation results of our techniques based on secret sharing that demonstrate practicality of the suggested protocols and also report on performance improvements due to our optimization techniques. Conclusions This work describes our techniques, findings, and experimental results developed and obtained as part of iDASH 2015 research competition to secure real-life genomic computations and shows feasibility of securely computing with genomic data in practice. PMID:26733307
Experimental comparison of PV-smoothing controllers using distributed generators
Johnson, Jay Dean [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ellis, Abraham [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Denda, Atsushi [Shimizu Corp., Tokyo (Japan); Morino, Kimio [Shimizu Corp., Tokyo (Japan); Hawkins, John N. [Public Service Company of New Mexico, Albuquerque, NM (United States); Arellano, Brian [Public Service Company of New Mexico, Albuquerque, NM (United States); Shinji, Takao [Tokyo Gas Co., New York, NY (United States); Ogata, Takao [Tokyo Gas Co., New York, NY (United States); Tadokoro, Masayuki [Tokyo Gas Co., New York, NY (United States)
2014-02-01
The power output variability of photovoltaic systems can affect local electrical grids in locations with high renewable energy penetrations or weak distribution or transmission systems. In those rare cases, quick controllable generators (e.g., energy storage systems) or loads can counteract the destabilizing effects by compensating for the power fluctuations. Previously, control algorithms for coordinated and uncoordinated operation of a small natural gas engine-generator (genset) and a battery for smoothing PV plant output were optimized using MATLAB/Simulink simulations. The simulations demonstrated that a traditional generation resource such as a natural gas genset in combination with a battery would smooth the photovoltaic output while using a smaller battery state of charge (SOC) range and extending the life of the battery. This paper reports on the experimental implementation of the coordinated and uncoordinated controllers to verify the simulations and determine the differences in the controllers. The experiments were performed with the PNM PV and energy storage Prosperity site and a gas engine-generator located at the Aperture Center at Mesa Del Sol in Albuquerque, New Mexico. Two field demonstrations were performed to compare the different PV smoothing control algorithms: (1) implementing the coordinated and uncoordinated controls while switching off a subsection of the PV array at precise times on successive clear days, and (2) comparing the results of the battery and genset outputs for the coordinated control on a high variability day with simulations of the coordinated and uncoordinated controls. It was found that for certain PV power profiles the SOC range of the battery may be larger with the coordinated control, but the total amp-hours through the battery-which approximates battery wear-will always be smaller with the coordinated control.
Validating MCNP for LEU Fuel Design via Power Distribution Comparisons
Primm, Trent [ORNL; Maldonado, G Ivan [ORNL; Chandler, David [ORNL
2008-11-01
The mission of the Reduced Enrichment for Research and Test Reactors (RERTR) Program is to minimize and, to the extent possible, eliminate the use of highly enriched uranium (HEU) in civilian nuclear applications by working to convert research and test reactors, as well as radioisotope production processes, to low enriched uranium (LEU) fuel and targets. Oak Ridge National Lab (ORNL) is reviewing the design bases and key operating criteria including fuel operating parameters, enrichment-related safety analyses, fuel performance, and fuel fabrication in regard to converting the fuel of the High Flux Isotope Reactor (HFIR) from HEU to LEU. The purpose of this study is to validate Monte Carlo methods currently in use for conversion analyses. The methods have been validated for the prediction of flux values in the reactor target, reflector, and beam tubes, but this study focuses on the prediction of the power density profile in the core. A current 3-D Monte Carlo N-Particle (MCNP) model was modified to replicate the HFIR Critical Experiment 3 (HFIRCE-3) core of 1965. In this experiment, the power profile was determined by counting the gamma activity at selected locations in the core. Foils (chunks of fuel meat and clad) were punched out of the fuel elements in HFIRCE-3 following irradiation and experimental relative power densities were obtained by measuring the activity of these foils and comparing each foil s activity to the activity of a normalizing foil. The current work consisted of calculating corresponding activities by inserting volume tallies into the modified MCNP model to represent the punchings. The average fission density was calculated for each foil location and then normalized to the normalizing foil. Power distributions were obtained for the clean core (no poison in moderator and symmetrical rod position at 17.5 inches) and fully poisoned-moderator (1.35 g B/liter in moderator and rods fully withdrawn) conditions. The observed deviations between the
Stability analysis for bad cavity lasers with inhomogeneously broadened gain
Kazakov, Georgy A
2016-01-01
Bad cavity lasers are experiencing renewed interest in the context of active optical frequency standards, due to their enhanced robustness against fluctuations of the laser cavity. The gain medium would consist of narrow-linewidth atoms, either trapped inside the cavity or intersecting the cavity mode dynamically. A finite velocity distribution, atomic interactions, or interactions of realistic multilevel atoms with external field leads to an inhomogeneous broadening of the atomic gain profile. This can bring the bad cavity laser to operate in unstable regimes characterized by complex temporal patterns of the field amplitude. We present a new and efficient method for the stability analysis of bad cavity lasers with inhomogeneously broadened gain. We apply this method to identify the steady-state solutions for the metrology-relevant case of spin-1/2 atoms interacting with an external magnetic field.
Bayesian Comparison of GARCH Processes with Skewness Mechanism in Conditional Distributions
Pipien, M
2006-01-01
The main goal of this paper is an application of Bayesian model comparison, based on the posterior probabilities and posterior odds ratios, in testing the explanatory power of the set of competing GARCH (ang. Generalised Autoregressive Conditionally Heteroscedastic) specifications, all with asymmetric and heavy tailed conditional distributions. In building competing volatility models we consider, as an initial specification, GARCH process with conditional Student-t distribution with unknown degrees of freedom parameter, proposed by Bollerslev (1987). By introducing skewness into Student-t family and incorporating the resulting class as a conditional distribution we generated various GARCH models, which compete in explaining possible asymmetry of both conditional and unconditional distribution of financial data. Based on the daily returns of hypothetical financial time series, we discuss the results of Bayesian comparison of alternative skewing mechanisms applied in the initial Student-t GARCH framework. We al...
Multispectral Imaging Broadens Cellular Analysis
2007-01-01
Amnis Corporation, a Seattle-based biotechnology company, developed ImageStream to produce sensitive fluorescence images of cells in flow. The company responded to an SBIR solicitation from Ames Research Center, and proposed to evaluate several methods of extending the depth of field for its ImageStream system and implement the best as an upgrade to its commercial products. This would allow users to view whole cells at the same time, rather than just one section of each cell. Through Phase I and II SBIR contracts, Ames provided Amnis the funding the company needed to develop this extended functionality. For NASA, the resulting high-speed image flow cytometry process made its way into Medusa, a life-detection instrument built to collect, store, and analyze sample organisms from erupting hydrothermal vents, and has the potential to benefit space flight health monitoring. On the commercial end, Amnis has implemented the process in ImageStream, combining high-resolution microscopy and flow cytometry in a single instrument, giving researchers the power to conduct quantitative analyses of individual cells and cell populations at the same time, in the same experiment. ImageStream is also built for many other applications, including cell signaling and pathway analysis; classification and characterization of peripheral blood mononuclear cell populations; quantitative morphology; apoptosis (cell death) assays; gene expression analysis; analysis of cell conjugates; molecular distribution; and receptor mapping and distribution.
Temporal scalability comparison of the H.264/SVC and distributed video codec
Huang, Xin; Ukhanova, Ann; Belyaev, E.; Forchhammer, Søren
The problem of the multimedia scalable video streaming is a current topic of interest. There exist many methods for scalable video coding. This paper is focused on the scalable extension of H.264/AVC (H.264/SVC) and distributed video coding (DVC). The paper presents an efficiency comparison of SVC...
Bats, J.W.; Feil, D.
1977-01-01
Electron density distributions, derived from ab initio molecular wavefunctions, have been calculated for CN− and SCN− ions. From these dynamic densities were calculated assuming rigid body thermal vibrations of the molecules. Comparison with the difference density in NaCN - 2H2O, NaSCN and NH4SCN, o
Broadening the concept of marketing.
Kotler, P; Levy, S J
1969-01-01
Marketing in business is the task of finding and stimulating buyers for a firms's output. Product development, pricing, distribution, and communication are the mainstays of marketing, while progressive firms also develop new products and chart the trends and changes in people's needs and desires. Marketing can either apply its knowledge to social problems and organizations or remain in a narrowly defined business activity. Every organization has basically the same functions: personnel management, production, income, and promotion, which are using modern marketing skills in commercial sectors. Suppliers and consumers are needed by all organizations. In Canada a group wished to promote an antismoking campaign but they had little money compared to the tobacco companies. This group used modern marketing techniques to combat their lack of funds and found many ways, e.g., books, articles. A business firm uses a multitude of marketing tools to sell its product. Nonbusiness organizations frequently do not integrate their programs the way the businesses place all activities under one marketing vice president and department. Astute marketing depends on continuous feedback from consumers and suppliers. They are dependent upon up-to-the-minute research that tells them about changes in the environment and moves of competitors. Nonbusiness organizations are often casual about the research upon which they base their vital decisions. PMID:12309673
Sound pulse broadening in stressed granular media.
Langlois, Vincent; Jia, Xiaoping
2015-02-01
The pulse broadening and decay of coherent sound waves propagating in disordered granular media are investigated. We find that the pulse width of these compressional waves is broadened when the disorder is increased by mixing the beads made of different materials. To identify the responsible mechanism for the pulse broadening, we also perform the acoustic attenuation measurement by spectral analysis and the numerical simulation of pulsed sound wave propagation along one-dimensional disordered elastic chains. The qualitative agreement between experiment and simulation reveals a dominant mechanism by scattering attenuation at the high-frequency range, which is consistent with theoretical models of sound wave scattering in strongly random media via a correlation length. PMID:25768496
Parton Energy Loss Without Transverse Momentum Broadening
Zapp, Korinna; Rathsman, Johan; Stachel, Johanna; Wiedemann, Urs Achim
2011-01-01
The JEWEL 1.0 Monte Carlo simulates jet evolution in a medium with a microscopic description of splitting and scattering processes. In the framework of this model we investigate the transverse momentum broadening due to medium effects in different scenarios. Depending on assumptions about hadronisation, we observe either a small increase or even a slight decrease of the mean transverse momentum, but no sizeable broadening. This appears to be a natural consequence of a model formulation which conserves energy and momentum microscopically at each splitting and at each scattering.
Pressure Broadening of Some He I Lines
Banaz Omar
2010-01-01
Full Text Available Quantum statistical approach is adopted for calculating the spectral line shapes of neutral helium in dense plasmas. Stark broadening of isolated He I lines 5048 Å (21P−41S, 3889 Å (23S−33P, and 3188Å (23S−43P is presented. Based on thermodynamic Green's function, the electronic contribution to the shift and width is considered. The participation of ions to the line broadening is treated in a quasistatic approximation, by taking both quadratic Stark effect and quadrupole interaction into account. The calculated shifts and widths are compared with existing data.
Figge, Stephan; Dartsch, Heiko; Aschenbrenner, Timo; Kruse, Carsten; Hommel, Detlef [University of Bremen (Germany)
2008-07-01
This paper investigates the feasibility of conductive Al-GaN reflectors with corRUGATEd (RUGATE) index profiles in comparison to standard distributed Bragg reflectors (DBR) and nested super lattice (NSL) DBRs. The samples are analyzed by reflectometry, X-ray diffraction, and electrical measurements. The RUGATE implementation of the reflectors exhibited two times higher vertical conductivity in comparison to the DBRs and showed slightly lower reflectivity. The nested super lattice approach for DBRs turned out to be an alternative which is easy to manufacture and which shows high reflectivity values. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
Broadening Our View of Linguistic Diversity
O'Neal, Debra; Ringler, Marjorie
2010-01-01
The definition of English language learners needs to be broadened to include the marginalized dialects of English. Not all native speakers speak Standard English, and even those who do need to learn Academic English to succeed in school. By using strategies developed for ELLs, teachers can help all students become fluent in the language of school.
Arvind, Pratul
2012-11-01
The ability to identify and classify all ten types of faults in a distribution system is an important task for protection engineers. Unlike transmission system, distribution systems have a complex configuration and are subjected to frequent faults. In the present work, an algorithm has been developed for identifying all ten types of faults in a distribution system by collecting current samples at the substation end. The samples are subjected to wavelet packet transform and artificial neural network in order to yield better classification results. A comparison of results between wavelet transform and wavelet packet transform is also presented thereby justifying the feature extracted from wavelet packet transform yields promising results. It should also be noted that current samples are collected after simulating a 25kv distribution system in PSCAD software.
CHEDDADI; Rachid; BEAUDOUIN; Celia
2008-01-01
The geographical distribution of dominant plant species in China was georeferenced and climatic variables were interpolated into all grids.Accordingly,the percentage distributions of principal pollen taxa based on 1860 surface pollen sites in China were selected and the related climate values were interpolated with the same method. The geographical and climatic comparison between the two data-sets indicated that the climate threshold of most pollen taxa from surface pollen is coherent with plant distributions. The climatic envelopes of dominant plant are mostly accordant with those of pollen taxa at certain levels. However, some distinct offsets of the climate ranges exist between the two datasets for most pollen taxa identified at family level, such as Ericaceae,Asteraceae, Poaceae and Chenopodiaceae. The present study provides for the first time rich information on temperature and precipitation in relation to pollen and plant distribution based on the datasets on a continental scale useful for global ecological modeling and Quaternary palaeoclimate reconstruction.
Hofstetter, Stefan
2013-01-01
This dissertation primarily aims at filling a number of gaps in the theory of comparison, in particular with respect to phrasal comparison in Turkish, intensifiers, Negative Island Effects and the cross-linguistic distribution of measure phrases. In its first main section, it provides a fairly exhaustive overview of the inventory of comparison constructions attested in the Turkish language and shows that the adverb daha is a largely optional element with these except for constructions th...
Porous silicon bandgap broadening at natural oxidation
Emission and excitation photoluminescence spectra of porous silicon thin layers have been investigated at natural oxidation. The shift of both types of spectra to high-energy region with time has been shown. Analysis of excitation spectra points out the indirect behavior of electron transitions responsible for visible photoluminescence, which remains unaltered at natural oxidation. The value of optical bandgap is estimated in each case. It is shown that the optical bandgap broadens during oxidation due to size reduction of silicon nanocrystallites. - Highlights: → Porous silicon emission and excitation spectra blue shifted at natural oxidation. → Excitation spectra points out the indirect behavior of electron transitions. → Optical bandgap broadens during oxidation due to Si nanoparticles size reduction.
Spatial distributions in static heavy-light mesons: a comparison of quark models with lattice QCD
Becirevic, Damir; Oliver, Alain Le Yaouanc Luis; Raynal, Jean-Claude
2011-01-01
Lattice measurements of spatial distributions of the light quark bilinear densities in static mesons allow to test directly and in detail the wave functions of quark models. These distributions are gauge invariant quantities directly related to the spatial distribution of wave functions. We make a detailed comparison of the recent lattice QCD results with our own quark models, formulated previously for quite different purposes. We find a striking agreement not only between our two quark models, but also with the lattice QCD data for the ground state in an important range of distances up to about 4/GeV. Moreover the agreement extends to the L=1 states [j^P=(1/2)^+]. An explanation of several particular features completely at odds with the non-relativistic approximation is provided. A rather direct, somewhat unexpected and of course approximate relation between wave functions of certain quark models and QCD has been established.
Flynn, A A; Green, A J; Boxer, G; Pedley, R B; Begent, R H
1999-07-01
Image registration is a powerful tool for correlating functional images with images of anatomical structure. This facilitates more accurate quantitation of regional radiopharmaceutical uptake. Similarly, registration of images of radiolabelled antibody distribution, in tissue sections, with the equivalent histological images allows the comparison and measurement of radiopharmaceutical distribution with morphological structure. The images used were obtained by storage phosphor plate technology, for the radiopharmaceutical distribution, and by digitization of the stained histological sections. Here we compare four fully automatic registration techniques and one manual technique in terms of their spatial accuracy. We have found that there was no difference in accuracy between cross-correlation, minimization of variance and mutual information. These techniques were more accurate than principal axes and the manual technique. However, minimization of variance and mutual information were more time-consuming than the other methods. Consequently, cross-correlation is the method of choice for automatic registration of large numbers of these image pairs. PMID:10442718
Image registration is a powerful tool for correlating functional images with images of anatomical structure. This facilitates more accurate quantitation of regional radiopharmaceutical uptake. Similarly, registration of images of radiolabelled antibody distribution, in tissue sections, with the equivalent histological images allows the comparison and measurement of radiopharmaceutical distribution with morphological structure. The images used were obtained by storage phosphor plate technology, for the radiopharmaceutical distribution, and by digitization of the stained histological sections. Here we compare four fully automatic registration techniques and one manual technique in terms of their spatial accuracy. We have found that there was no difference in accuracy between cross-correlation, minimization of variance and mutual information. These techniques were more accurate than principal axes and the manual technique. However, minimization of variance and mutual information were more time-consuming than the other methods. Consequently, cross-correlation is the method of choice for automatic registration of large numbers of these image pairs. (author)
On pulse broadening for optical solitons
Dorren, H J S
1999-01-01
Pulse broadening for optical solitons due to birefringence is investigated. It is shown that in optical fibers with birefringence no pure solitons exist. We present analytical expressions for special solitonic solutions in birefringent optical fibers consisting of a combination of pure solitons propagating along the principal birefringence axis with a different velocity and interaction terms between the solitons. An estimation for the stability of the derived solutions and random polarization mode dispersion is given.
A broad-standard technique for correcting for band broadening in size-exclusion chromatography.
Zhang, Peng; Mazoyer, Paul; Gilbert, Robert G
2016-04-22
Band broadening in size-exclusion chromatography (SEC) is always present to some extent. Broadening effects on averages such as the weight- and number average molecular weights (MW¯ and Mn¯ respectively) are minimal with modern SEC systems. However, broadening distorts the shape of the true molecular weight distribution (MWD), which causes problems if one wants to compare the detailed form of the MWD to a model. An addition to current methods for overcoming this problem is presented. One starts with a sufficiently wide range of samples whose exact values of Mn¯ andMW¯ have been measured by non-SEC methods (e.g. by fluorimetry and light scattering, respectively, of the sample without size separation). A true (unbroadened) molecular weight distribution for a sample can be obtained by deconvolution (here using a maximum-entropy algorithm) by fitting SEC data for these samples to these exact Mn¯ and MW¯ values to find the values of the parameters in a sufficiently flexible assumed broadening function. This was modelled using simulated band broadening and subsequent deconvolution, with the broadening parameters least-squares fitted to the "exact" sets of values of Mn¯ and MW¯. The results show that if these Mn¯ and MW¯ values are for a series of broad (not narrow) standards covering a sufficient range of molecular weight, then after deconvolution, a good representation of the original molecular weight distribution used in the simulation is obtained. The method should prove useful for water-soluble polymers, for which it is often difficult to obtain narrow standards of a wide range of molecular weight, as required in a number of well-established methods for correcting for band broadening. PMID:27016112
Study of stark broadening of high-Z hydrogenic ion lines in dense hot plasmas
Stark broadened x-ray line profiles from highly ionized hydrogenic ions, radiating while immersed in a hot dense plasma, are studied. The broadening effects produced by the ions present in the plasma are treated through the use of static electric microfield distribution functions. The microfield distribution functions employed have the following properties: (1) the radiating hydrogenic ion may have any net charge; (2) the perturbing ions and electrons in the plasma may have different kinetic temperatures; and (3) two species of ions, of charge z1 and z2, may be present in any given ratio
Xudong Zhao
2015-01-01
Full Text Available Water distribution network (WDN is critical to the city service, economic rehabilitation, public health, and safety. Reconstructing the WDN to improve its resilience in seismic disaster is an important and ongoing issue. Although a considerable body of research has examined the effects of different reconstruction strategies on seismic resistance, it is still hard for decision-makers to choose optimal resilience enhancing strategy. Taking the pipeline ductile retrofitting and network meshed expansion as demonstration, we proposed a feasible framework to contrast the resilience enhancing effects of two reconstruction strategies—units retrofitting strategy and network optimization strategy—in technical and organizational dimension. We also developed a new performance response function (PRF which is based on network equilibrium theory to conduct the effects comparison in integrated technical and organizational dimension. Through the case study of municipal WDN in Lianyungang, China, the comparison results were thoroughly shown and the holistic decision-making support was provided.
Analysis of neutron diffraction peak broadening caused by internal stresses in composite materials
Neutron diffraction is an essential tool in the study of internal stresses in composite materials. In most work only the peak shifts caused by the related elastic strains are considered, but other valuable information exists in the form of peak shape changes. The conditions under which the pure diffraction profile of the composite (i.e. the profile when all sources of broadening not caused by the residual stresses are removed) represents the probability distribution of the peak shifts corresponding to the strains are examined. It is shown that in these conditions, the pure diffraction profile has no attributes of particle size broadening (and vice versa), thereby providing a test for the validity of results interpreted in this way. The experimental derivation of measured strain distributions in Al2O3/SiCp composites using neutron diffraction is described. No apparent particle size broadening was detected, demonstrating the validity of the results, which also satisfied other tests for consistency
Ramin Shamshiri
2014-01-01
Full Text Available Wave propagation and heat distribution are both governed by second order linear constant coefficient partial differential equations, however their solutions yields very different properties. This study presents a comprehensive comparison between hyperbolic wave equation and parabolic heat equation. Issues such as conservation of wave profile versus averaging, transporting information, finite versus infinite speed propagation, time reversibility versus irreversibility and propagation of singularities versus instantaneous smoothing have been addressed and followed by examples and graphical evidences from computer simulations to support the arguments.
Comparison of sea-ice freeboard distributions from aircraft data and cryosat-2
Ricker, Robert; Hendricks, Stefan; Helm, Veit;
2012-01-01
highly accurate range measurements. During the CryoSat Validation Experiment (CryoVEx) 2011 in the Lincoln Sea Cryosat-2 underpasses were accomplished with two aircraft which carried an airborne laser scanner, a radar altimeter and an electromagnetic induction device for direct sea ice thickness...... retrieval. Both aircraft flew in close formation at the same time of a CryoSat-2 overpass. This is a study about the comparison of the sea-ice freeboard distribution of laser scanner and radar altimeter measurements with the CryoSat-2 product within the multi-year sea ice region of the Lincoln Sea in spring...
Comparison of sea-ice freeboard and thickness distributions from aircraft data and cryosat-2
accurate range measurements. During the CryoSat Validation Experiment (CryoVEx) 2011 in the Lincoln Sea, Cryosat-2 underpasses were accomplished with two aircraft, which carried an airborne laser-scanner, a radar altimeter and an electromagnetic induction device for direct sea-ice thickness retrieval. Both...... aircraft flew in close formation at the same time of a CryoSat-2 overpass. This is a study about the comparison of the sea-ice freeboard and thickness distribution of airborne validation and CryoSat-2 measurements within the multi-year sea-ice region of the Lincoln Sea in spring, with respect to the...
Smail, Linda
2016-06-01
The basic task of any probabilistic inference system in Bayesian networks is computing the posterior probability distribution for a subset or subsets of random variables, given values or evidence for some other variables from the same Bayesian network. Many methods and algorithms have been developed to exact and approximate inference in Bayesian networks. This work compares two exact inference methods in Bayesian networks-Lauritzen-Spiegelhalter and the successive restrictions algorithm-from the perspective of computational efficiency. The two methods were applied for comparison to a Chest Clinic Bayesian Network. Results indicate that the successive restrictions algorithm shows more computational efficiency than the Lauritzen-Spiegelhalter algorithm.
Speed-dependent effects and Dicke narrowing in nitrogen-broadened oxygen
Wójtewicz, S.; Masłowski, P.; Cygan, A.; Wcisło, P.; Zaborowski, M.; Piwiński, M.; Ciuryło, R.; Lisak, D.
2015-11-01
We present the line-shape analysis of the nitrogen-broadened P9 P9 oxygen B-band transition measured by the optical frequency comb-assisted Pound-Drever-Hall-locked frequency-stabilized cavity ring-down spectrometer. Perturbation by both oxygen and nitrogen molecules is taken into account simultaneously in the line-shape analysis. Several line-shape models describing physical effects such as Dicke narrowing, the speed dependence of collisional broadening and shifting, and the correlation between velocity- and phase-changing collisions were used in the analysis. The comparison between the hypergeometric and quadratic approximations of the speed-dependent effects is presented. Observed line narrowing is mostly determined by the speed dependence of the collisional broadening.
Retention and distribution of 226Ra in beagles: a comparison between multiple and single injections
Skeletal uptake, retention, and distribution of 226Ra were studied in 330 beagles administered eight semi-monthly i.v. injections of radium starting at 2, 4, and 14 months of age. Skeletal uptake, the ratio of body burden at 35 days post-injection (A35) to the total injected dose (A0) was 71.7 percent, 78.1 percent and 38.5 percent, for a dose of 10 μCi/kg body weight administered starting at 2, 4, and 14 months of age, respectively. Skeletal retention of radium 350 days post-injection (A350/A0) was 67.2 percent, 73.3 percent, and 27.7 percent. Comparison of 226Ra retention from single and multiple injections of radium shows that at dose level 6.064 μCi/kg the retention functions for periods 35 days after injection are identical; for dose level 10 μCi/kg, a larger retention is observed for multiple-injection groups. Comparison of 226Ra retention in man with that in beagles shows that within a period between 35 days and 6000 days post--injection, the body burden in dog decreases by about 6 times in contrast with 43 times in man. Regional distribution of 226Ra in bone matrix at proximal, midshaft, and distal humeri from 21 beagles shows the highest concentration of the radionuclide at proximal regions. Radium distribution on autoradiograms shows a uniform distribution in 4-month-old beagles in contrast to ''hot spots'' superimposed on a diffuse background for the 14-month age group. Radium in the latter group is located mostly on periosteum and endosteum surfaces
Anomalous broadening of energy distributions in photoemitted electron beams
Guidi, Vincenzo
1996-06-01
Photoemission is widely used to generate electron beams with an energy spread lower than by thermoemission. However, when a photocathode is illuminated by a multimode laser this feature is lost and an electron beam with several eV of energy spread is produced. We have developed an explanation for this anomalous behavior pointing out its origin in the combined effect of charge relaxation, taking place within the beam, together with the modulation of the laser power imposed by laser modes. The model permits a correct interpretation overall experimental evidences.
Eliciting hyperparameters of prior distributions for the parameters of paired comparison models
Nasir Abbas
2013-02-01
Full Text Available Normal 0 false false false EN-US X-NONE AR-SA In the study of paired comparisons (PC, items may be ranked or issues may be prioritized through subjective assessment of certain judges. PC models are developed and then used to serve the purpose of ranking. The PC models may be studied through classical or Bayesian approach. Bayesian inference is a modern statistical technique used to draw conclusions about the population parameters. Its beauty lies in incorporating prior information about the parameters into the analysis in addition to current information (i.e. data. The prior and current information are formally combined to yield a posterior distribution about the population parameters, which is the work bench of the Bayesian statisticians. However, the problems the Bayesians face correspond to the selection and formal utilization of prior distribution. Once the type of prior distribution is decided to be used, the problem of estimating the parameters of the prior distribution (i.e. elicitation still persists. Different methods are devised to serve the purpose. In this study an attempt is made to use Minimum Chi-square (hence forth MCS for the elicitation purpose. Though it is a classical estimation technique, but is used here for the election purpose. The entire elicitation procedure is illustrated through a numerical data set.
Naturally occurring porous media are usually characterized by a distribution of pore sizes. If the material is fluid saturated, the 1H magnetic resonance (MR) signal depends on the pore size, the surface relaxivity and the fluid itself. Measurement of the transverse relaxation time T2 is a well-established technique to characterize material samples by means of MR. T2 distribution measurements, including T2 distribution mapping, are widely employed in clinical applications and in petroleum engineering. T2 distribution measurements are the most basic measurement employed to determine the fluid-matrix properties in MR core analysis. Three methods for T2 distribution mapping, namely spin-echo single point imaging (SE-SPI), DANTE-Z Carr–Purcell–Meiboom–Gill (CPMG) and adiabatic inversion CPMG are compared in terms of spatial resolution, minimum observable T2 and sensitivity. Bulk CPMG measurement is considered to be the gold standard for T2 determination. Bulk measurement of uniform samples is compared to the three spatially resolved measurements. SE-SPI is an imaging method, which measures spatially resolved T2s in samples of interest. A variant is introduced in this work that employs pre-equalized magnetic field gradient waveforms and is therefore able to measure shorter T2s than previously reported. DANTE-Z CPMG and adiabatic inversion CPMG are faster, non-imaging, local T2 distribution measurements. The DANTE-Z pulse train and adiabatic inversion pulse are compared in terms of T1 or T2 relaxation time effects during the RF pulse application, minimum pulse duration, requisite RF pulse power, and inversion profile quality. In addition to experimental comparisons, simulation results are presented. (paper)
Gholami, Mohammad; Brennan, Robert W
2016-01-01
In this paper, we investigate alternative distributed clustering techniques for wireless sensor node tracking in an industrial environment. The research builds on extant work on wireless sensor node clustering by reporting on: (1) the development of a novel distributed management approach for tracking mobile nodes in an industrial wireless sensor network; and (2) an objective comparison of alternative cluster management approaches for wireless sensor networks. To perform this comparison, we focus on two main clustering approaches proposed in the literature: pre-defined clusters and ad hoc clusters. These approaches are compared in the context of their reconfigurability: more specifically, we investigate the trade-off between the cost and the effectiveness of competing strategies aimed at adapting to changes in the sensing environment. To support this work, we introduce three new metrics: a cost/efficiency measure, a performance measure, and a resource consumption measure. The results of our experiments show that ad hoc clusters adapt more readily to changes in the sensing environment, but this higher level of adaptability is at the cost of overall efficiency. PMID:26751447
Broadening of dielectric response and sum rule conservation
Different types of broadening of the dielectric response are studied with respect to the preservation of the Thomas–Reiche–Kuhn sum rule. It is found that only the broadening of the dielectric function and transition strength function conserve this sum rule, whereas the broadening of the transition probability function (joint density of states) increases or decreases the sum. The effect of different kinds of broadening is demonstrated for interband and intraband direct electronic transitions using simplified rectangular models. It is shown that the broadening of the dielectric function is more suitable for interband transitions while broadening of the transition strength function is more suitable for intraband transitions. - Highlights: • Preservation of the sum rule by different types of dielectric response broadening • Only broadening of dielectric function and transition strength function preserves it. • Broadening of joint density of states does not preserve the sum rule. • Broadening of dielectric function is better for direct interband transitions. • Broadening of transition strength is better for indirect interband transitions
A broadened typology on energy and security
A broadened typology describing the interconnection between energy and security is developed in this paper, with the aim of improving understanding of the relationship between energy and security by applying different research and policy perspectives. One approach involves studying energy as an object exposed to security threats, using concepts such as security of supply or security of demand. Another approach involves studying the role of the energy system as the subject in generating or enhancing insecurity. The latter approach includes studying the conflict-generating potential inherent in the economic value of energy, the risk of accidents and antagonistic attacks to energy infrastructure and the security risks related to the negative environmental impact of the energy system. In order to make a comprehensive analysis of the security consequences of proposed energy policies or strategies, all these aspects should be taken into account to varying degrees. The typology proposed here could be a valuable tool for ensuring that all security aspects have been considered. - Highlights: • The paper presents a broadened typology of energy and security, useful for policy analysis. • The energy system can be an object for security threats and as a subject generating or contributing to insecurity. • Energy as an object for security threats includes the concepts of security of supply and security of demand. • The economic value of energy can contribute to insecurity. • Technological and environmental risks of specific energy systems also provide potential threats to human security
Windowed multipole for cross section Doppler broadening
Josey, C.; Ducru, P.; Forget, B.; Smith, K.
2016-02-01
This paper presents an in-depth analysis on the accuracy and performance of the windowed multipole Doppler broadening method. The basic theory behind cross section data is described, along with the basic multipole formalism followed by the approximations leading to windowed multipole method and the algorithm used to efficiently evaluate Doppler broadened cross sections. The method is tested by simulating the BEAVRS benchmark with a windowed multipole library composed of 70 nuclides. Accuracy of the method is demonstrated on a single assembly case where total neutron production rates and 238U capture rates compare within 0.1% to ACE format files at the same temperature. With regards to performance, clock cycle counts and cache misses were measured for single temperature ACE table lookup and for windowed multipole. The windowed multipole method was found to require 39.6% more clock cycles to evaluate, translating to a 7.9% performance loss overall. However, the algorithm has significantly better last-level cache performance, with 3 fewer misses per evaluation, or a 65% reduction in last-level misses. This is due to the small memory footprint of the windowed multipole method and better memory access pattern of the algorithm.
Line broadening and the solar opacity problem
Krief, M; Gazit, D
2016-01-01
The calculation of line widths constitutes a theoretical as well as a computational challenge in the calculation of opacities of hot dense plasmas. Opacity models use line broadening approximations that are untested at stellar interior conditions. Moreover, calculations of atomic spectra nearby the convection zone boundary (CZB) of the sun, indicate a large discrepancy in the K-shell line widths between several atomic codes and the Opacity-Project. In this work, the atomic code STAR is used to study the sensitivity of solar opacities to line-broadening. Atomic spectra of several elements are analyzed and compared within the solar interior. Variations in the solar opacity profile due to changes in the Stark widths are shown to be significant and to result mainly due to K-shell lines. In light of the solar opacity problem, the results are compared with the required opacity variations of the present day sun, as imposed by helioseismic and neutrino observations. It is shown that an increase of the line widths res...
Commitment to Broadening Participation at NOAO
Garmany, Catharine D.; Norman, D.
2011-01-01
AURA and NOAO take seriously the importance of Broadening Participation in Astronomy. At the request of the AURA President, each of the AURA centers (NOAO, NSO, STSCI, Gemini) appointed a Diversity Advocates (DA). At NOAO this job is shared by Dara Norman and Katy Garmany, who were appointed by Dave Silva in Jan 2009. The DA's are members of the AURA Committee on Workforce and Diversity (WDC), a designated subcommittee of the AURA Board of Directors. The role of this committee includes reviewing activities and plans on an AURA wide basis aimed at broadening the participation within AURA, and reviewing AURA wide policies on the workforce. At NOAO, the role of the DAs spans a number of departments and activities. They serve on observatory search committees, and offer suggestions on how NOAO job searches can reach the most diverse audience. The DA's job is to insure that NOAO actively pursues every opportunity to increase diversity: to this end they are involved in outreach and educational activities that focus on workplace development and encourage inclusion of woman, minorities and persons with disabilities.
Action potential broadening in a presynaptic channelopathy
Begum, Rahima; Bakiri, Yamina; Volynski, Kirill E.; Kullmann, Dimitri M.
2016-07-01
Brain development and interictal function are unaffected in many paroxysmal neurological channelopathies, possibly explained by homoeostatic plasticity of synaptic transmission. Episodic ataxia type 1 is caused by missense mutations of the potassium channel Kv1.1, which is abundantly expressed in the terminals of cerebellar basket cells. Presynaptic action potentials of small inhibitory terminals have not been characterized, and it is not known whether developmental plasticity compensates for the effects of Kv1.1 dysfunction. Here we use visually targeted patch-clamp recordings from basket cell terminals of mice harbouring an ataxia-associated mutation and their wild-type littermates. Presynaptic spikes are followed by a pronounced afterdepolarization, and are broadened by pharmacological blockade of Kv1.1 or by a dominant ataxia-associated mutation. Somatic recordings fail to detect such changes. Spike broadening leads to increased Ca2+ influx and GABA release, and decreased spontaneous Purkinje cell firing. We find no evidence for developmental compensation for inherited Kv1.1 dysfunction.
Broadening of ICRH produced fast ion profiles due to orbit effects
In the JET tokamak, minority ions accelerated by ICRH reach energies in the MeV range. Near the plasma magnetic axis, the standard trapped particle ''banana'' orbit is distorted into a ''potato'' or ''fat banana'' orbit. The zero banana width approximation which is used in most Fokker-Planck calculations of velocity distributions of resonating ions is often not valid in JET. The inclusion of finite banana width effects will, in general, lead to a lowering of the averaged tail energy and a broadening of pressure profiles, power transfer profiles etc. A model for calculating orbit broadened profiles is presented. (Author)
Broadening the focus of evaluation: An experiment
Chakraborty, S.
2010-01-01
Full Text Available Evaluation of student performance in any course, especially those delivered in a management programme, poses a serious challenge; more so, in a course like ‘Business Communication’, where oral communication ought to form an integral part of evaluation. This paper presents various details of an experiment, conducted with a view to introduce this much needed component in the evaluation process. Essential purpose of the exercise was to try and broaden the focus of evaluation, simultaneously enlarging its scope. The need to maintain certain amount of objectivity and transparency was taken as critical. Group Discussion was used as a tool. A process was developed with the objective of getting every student evaluated on both written as well as non-written skills. A two-sided evaluation mechanism was put in place to achieve the dual purpose of leaning and evaluation. Statistical analysis of the results suggests that the experiment was a useful one. The student feedback, too, was favourable.
Covalent organic framework-1 (COF-1) has been synthesized and its textural characteristics determined via surface analyzer and scanning electron microscope (SEM). Fourier transform infra-red (FTIR) analysis has also been conducted to determine the types of covalent bonding present in the material. Our customized synthesis procedure yields a COF-1 powder consisting of granular-shaped bulk particles with approximate diameters ranging from 0.5 to 0.8 μm. Results comparison of three established and commonly-used pore size distribution models, namely, Barret-Joyner-Halenda (BJH), Horvath-Kawazoe (HK) and Density Functional Theory (DFT) reveals that the DFT model is the most appropriate model for COF-1 due to limitation of porosity range of the other two models.
Structure and broadening coefficients (He, Ar and N2) of the ν4 band of CF4
Spectra of CF4 in the ν4 fundamental band region have been recorded in pure gas and in mixtures with He, Ar and N2 at resolution up to 0.003 cm-1. Obtained data allowed us to evaluate the integrated band intensity, line intensity distribution and effective broadening coefficients for J-multiplets. The broadening coefficient behavior is similar to that previously registered for linear molecules: they coincide for P and R branches; the J-dependence in the case of argon is more pronounced than that for helium. The broadening coefficients for nitrogen and helium are practically the same but the values for nitrogen are scattered around the general trend. Q-branch broadening is different from that for J-manifolds. The coefficients of branch broadening are noticeably smaller. Nitrogen broadening is very close to result for the case of argon though there is a marked difference between them for J-manifolds. Collisions with argon and nitrogen broaden the Q-branch almost 3 times more effectively than collisions with helium
Hot Water Distribution System Program Documentation and Comparison to Experimental Data
Baskin, Evelyn [GE Infrastructure Energy; Craddick, William G [ORNL; Lenarduzzi, Roberto [ORNL; Wendt, Robert L [ORNL; Woodbury, Professor Keith A. [University of Alabama, Tuscaloosa
2007-09-01
In 2003, the California Energy Commission s (CEC s) Public Interest Energy Research (PIER) program funded Oak Ridge National Laboratory (ORNL) to create a computer program to analyze hot water distribution systems for single family residences, and to perform such analyses for a selection of houses. This effort and its results were documented in a report provided to CEC in March, 2004 [1]. The principal objective of effort was to compare the water and energy wasted between various possible hot water distribution systems for various different house designs. It was presumed that water being provided to a user would be considered suitably warm when it reached 105 F. Therefore, what was needed was a tool which could compute the time it takes for water reaching the draw point to reach 105 F, and the energy wasted during this wait. The computer program used to perform the analyses was a combination of a calculational core, produced by Dr. Keith A. Woodbury, Professor of Mechanical Engineering and Director, Alabama Industrial Assessment Center, University of Alabama, and a user interface based on LabVIEW, created by Dr. Roberto Lenarduzzi of ORNL. At that time, the computer program was in a relatively rough and undocumented form adequate to perform the contracted work but not in a condition where it could be readily used by those not involved in its generation. Subsequently, the CEC provided funding through Lawrence Berkeley National Laboratory (LBNL) to improve the program s documentation and user interface to facilitate use by others, and to compare the program s results to experimental data generated by Dr. Carl Hiller. This report describes the program and provides user guidance. It also summarizes the comparisons made to experimental data, along with options built into the program specifically to allow these comparisons. These options were necessitated by the fact that some of the experimental data required options and features not originally included in the program
Edwards, David L.; Cooke, William; Scruggs, Rob; Moser, Danielle E.
2008-01-01
The National Aeronautics and Space Administration (NASA) is progressing toward long-term lunar habitation. Critical to the design of a lunar habitat is an understanding of the lunar surface environment; of specific importance is the primary meteoroid and subsequent ejecta environment. The document, NASA SP-8013, was developed for the Apollo program and is the latest definition of the ejecta environment. There is concern that NASA SP-8013 may over-estimate the lunar ejecta environment. NASA's Meteoroid Environment Office (MEO) has initiated several tasks to improve the accuracy of our understanding of the lunar surface ejecta environment. This paper reports the results of experiments on projectile impact into powered pumice and unconsolidated JSC-1A Lunar Mare Regolith stimulant (JSC-1A) targets. The Ames Vertical Gun Range (AVGR) was used to accelerate projectiles to velocities in excess of 5 km/s and impact the targets at normal incidence. The ejected particles were detected by thin aluminum foil targets placed around the impact site and angular distributions were determined for ejecta. Comparison of ejecta angular distribution with previous works will be presented. A simplistic technique to characterize the ejected particles was formulated and improvements to this technique will be discussed for implementation in future tests.
Interspecies comparison of the tissue distribution of WR-2721, a radioprotective drug
Pre-irradiation intravenous administration of the radioprotective drug S-2-[3-aminopropylamino]ethylphosphorothioic acid (WR-2721) has potential value in radiotherapy because it doubles the radiation resistance of normal mouse tissues while affording only minimal protection to tumors. Deficient deposition of WR- 2721 in tumor tissue has recently been demonstrated and this is thought to be a major reason for the preferential protection of normal tissues by the drug. Data originally obtained in studies using the mouse and rat indicated that the tissue distribution of WR-2721 was possibly more closely related to dose per unit surface area than to dose per unit weight. To test this hypothesis an interspecies comparison of the tissue distribution of 35S-labeled WR-2721 was carried out in normal mice, rats, rabbits, and dogs at 15 and 30 minutes after intravenous administration. Results suggest that the surface area and body weight exert equal effects on the tissue concentration of WR-2721. The results further suggest that lower absolute doses of WR-2721 in the human, possibly as low as 20 mg/kg, may provide a radioprotective effect equivalent to that produced from 100 mg/kg in the mouse, i.e., a 50 to 80 percent increase in radiation resistance (CH)
Comparison of measured and calculated reaction rate distributions in an scwr-like test lattice
High resolution gamma-ray spectroscopy measurements were performed on 61 rods of an SCWR-like fuel lattice, after irradiation in the central test zone of the PROTEUS zero-power research reactor at the Paul Scherrer Institute in Switzerland. The derived reaction rates are the capture rate in 238U (C8) and the total fission rate (Ftot), and also the reaction rate ratio C8/Ftot. Each of these has been mapped rod-wise on the lattice and compared to calculated results from whole-reactor Monte Carlo simulations with MCNPX. Ratios of calculated to experimental values (C/E's) have been assessed for the C8, Ftot and C8/Ftot distributions across the lattice. These C/E's show excellent agreement between the calculations and the measurements. For the 238U capture rate distribution, the 1σ level in the comparisons corresponds to an uncertainty of ±0.8%, while for the total fission rate the corresponding value is ±0.4%. The uncertainty for C8/Ftot, assessed as a reaction rate ratio characterizing each individual rod position in the test lattice, is significantly higher at ±2.2%. To determine the reproducibility of these results, the measurements were performed twice, once in 2006 and again in 2009. The agreement between these two measurement sets is within the respective statistical uncertainties.
Measured and Theoretical Self- and N(2)-Broadened Line Parameters in the ν6 Band of CH(3)D
Devi, V. Malathy; Benner, D. Chris; Sung, Keeyon; Predoi-Cross, Adriana; Smith, Mary Ann H.; Mantz, Arlan W.; Sinyakova, Tatyana; Buldyreva, Jeanna
2014-06-01
Monodeuterated methane (CH3D) is a constituent trace species in several planetary atmospheres, and its spectrum is often used in determinations of atmospheric H/D ratios. Methane plays an important role in terrestrial atmospheric chemistry. It is the most abundant hydrocarbon in our atmosphere and as an IR active gas makes an important contribution to the enhanced greenhouse effect. Methane is increasing in the Earth's atmosphere at a rate of about 1% per year. The current knowledge of its sources and sinks are not sufficient to isolate the cause of the observed changes in the mixing ratio and global distribution. As a result, the infrared spectrum of methane and its isotopomers is continually being investigated in order to obtain improved spectroscopic line parameters needed to interpret remote sensing observations. Remote sensing instruments require laboratory data sets based on measurements of very high accuracy. The primary objective of this study is to enhance our spectroscopic knowledge of monodeuterated methane in theν6 band located at 6.8 microns. We present measurement results for self- and N2-broadened line parameters from room temperature down to about 80 K. A total of 23 high-resolution, high S/N spectra recorded with two Fourier transform spectrometers: a) the McMath-Pierce FTS located on Kitt Peak and b) a Bruker IFS-125HR FTS at the Jet Propulsion Laboratory (JPL) 1 were fit simultaneously in a multispectrum approach. 2 The set included both pure CH3D and dilute mixtures of CH3D in research grade nitrogen. The variations in the measured line parameters with the symmetry species, the rotational quantum numbers and with temperature are reported and discussed in comparison with earlier measurements. For the case of nitrogen-broadening, we also provide semi-classical calculations based on a rigorous treatment of the active molecule as a symmetric top, a model intermolecular potential comprising both short- and long-range interactions, and exact
RESONANCE BROADENING AND HEATING OF CHARGED PARTICLES IN MAGNETOHYDRODYNAMIC TURBULENCE
The heating, acceleration, and pitch-angle scattering of charged particles by magnetohydrodynamic (MHD) turbulence are important in a wide range of astrophysical environments, including the solar wind, accreting black holes, and galaxy clusters. We simulate the interaction of high-gyrofrequency test particles with fully dynamical simulations of subsonic MHD turbulence, focusing on the parameter regime with β ∼ 1, where β is the ratio of gas to magnetic pressure. We use the simulation results to calibrate analytical expressions for test particle velocity-space diffusion coefficients and provide simple fits that can be used in other work. The test particle velocity diffusion in our simulations is due to a combination of two processes: interactions between particles and magnetic compressions in the turbulence (as in linear transit-time damping; TTD) and what we refer to as Fermi Type-B (FTB) interactions, in which charged particles moving on field lines may be thought of as beads sliding along moving wires. We show that test particle heating rates are consistent with a TTD resonance that is broadened according to a decorrelation prescription that is Gaussian in time (but inconsistent with Lorentzian broadening due to an exponential decorrelation function, a prescription widely used in the literature). TTD dominates the heating for vs >> vA (e.g., electrons), where vs is the thermal speed of species s and vA is the Alfvén speed, while FTB dominates for vs A (e.g., minor ions). Proton heating rates for β ∼ 1 are comparable to the turbulent cascade rate. Finally, we show that velocity diffusion of collisionless, large gyrofrequency particles due to large-scale MHD turbulence does not produce a power-law distribution function.
Karp, Jeffrey A.; Bowler, Shaun
2006-01-01
The European Union sees the inclusion of many Eastern European states -enlargement- as a natural progression in the process of building an 'ever closer union'. For the European Commission in particular, the process of enlargement (broadening) is part of the process of integration and acts as a complement to the development of a stronger role for the European Union and its institutions or deepening of integration. Yet as the first Irish referendum on the Nice Treaty showed, not all of European...
In this study, electron collisional broadening of observed spectral lines depends on plasma electron temperature and density. Including this effect in models of measured spectra is necessary to determine plasma conditions; however, computational limits make accurate line broadening treatments difficult to implement in large-scale plasma modeling efforts. In this paper, we report on improvements to the treatment of electron collisional line broadening and illustrate this with calculations using the Los Alamos ATOMIC code. We implement the Dimitrijevic and Konjevic modified semi-empirical model Dimitrijevic and Konjevic (1986 Astron. and Astrophy. 163 297 and 1987 Astron. Astrophys. 172 345), which we amend by employing oscillator strengths from Hartree-Fock calculations. This line broadening model applies to near-neutral plasmas with electron temperatures of Te ~ 1 eV and electron densities of Ne ~1017 cm-3. We evaluate the D.K.-inspired model against the previous hydrogenic approach in ATOMIC through comparison to NIST-rated measurements for selected neutral and singly-ionized Ca, O, Fe, and Sn lines using both fine-structure and configuration-averaged oscillator strengths. The new D.K.-inspired model is significantly more accurate than the previous hydrogenic model and we find the use of configuration-averaged oscillator strengths a good approximation for applications such as LIBS (laser induced breakdown spectroscopy), for which we demonstrate the use of the D.K.-inspired model
Doppler radar spectral width broadening due to beamwidth and wind shear
G. D. Nastrom
Full Text Available The spectral width observed by Doppler radars can be due to several effects including the atmospheric turbulence within the radar sample volume plus effects associated with the background flow and the radar geometry and configuration. This study re-examines simple models for the effects due to finite beamwidth and vertical shear of the horizontal wind. Analytic solutions of 1- and 2-dimensional models are presented. Comparisons of the simple 2-dimensional model with numerical integrations of a 3-dimensional model with a symmetrical Gaussian beam show that the 2-dimensional model is usually adequate. The solution of the 2-dimensional model gives a formula that can be applied easily to large data sets. Analysis of the analytic solutions of the 2-dimensional model for off-vertical beams reveals a term that has not been included in mathematical formulas for spectral broadening in the past. This term arises from the simultaneous effects of the changing geometry due to curvature within a finite beamwidth and the vertical wind shear. The magnitude of this effect can be comparable to that of the well-known effects of beam-broadening and wind shear, and since it can have either algebraic sign, it can significantly reduce (or increase the expected spectral broadening, although under typical conditions it is smaller than the beam-broadening effect. The predictions of this simple model are found to be consistent with observations from the VHF radar at White Sands Missile Range, NM.
Muntasir, Tanvir, E-mail: tanvir@iastate.edu, E-mail: sumitc@iastate.edu [Department of Electrical and Computer Engineering, Iowa State University, Ames, Iowa 50011 (United States); Chaudhary, Sumit, E-mail: tanvir@iastate.edu, E-mail: sumitc@iastate.edu [Department of Electrical and Computer Engineering, Iowa State University, Ames, Iowa 50011 (United States); Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States)
2015-11-28
Organic photovoltaics (OPVs) are regarded as promising for solar-electric conversion with steadily improving power conversion efficiencies. For further progress, it is crucial to understand and mitigate defect states (traps) residing in the band-gap of OPV materials. In this work, using capacitance measurements, we analyzed two major bands in the density of states (DOS) energy spectra of defects in poly(3-hexylthiophene) (P3HT); regio-regular and regio-random species of P3HT were compared to elucidate the role of morphological disorder. To accurately interpret the obtained DOS profile, trap emission prefactors and activation energy were extracted from temperature dependent capacitance-frequency measurements, while doping, Fermi energy, built-in voltage, and energy levels of the defects were extracted from capacitance-voltage measurements. We identified that the lower energy band—misinterpreted in literature as a defect distribution—stems from free carrier response. The higher energy defect distribution band for regio-random P3HT was an order of magnitude higher than region-regular P3HT, thus stemming from morphological disorder. Impedance spectroscopy was also employed for further comparison of the two P3HT species.
Muntasir, Tanvir; Chaudhary, Sumit
2015-11-01
Organic photovoltaics (OPVs) are regarded as promising for solar-electric conversion with steadily improving power conversion efficiencies. For further progress, it is crucial to understand and mitigate defect states (traps) residing in the band-gap of OPV materials. In this work, using capacitance measurements, we analyzed two major bands in the density of states (DOS) energy spectra of defects in poly(3-hexylthiophene) (P3HT); regio-regular and regio-random species of P3HT were compared to elucidate the role of morphological disorder. To accurately interpret the obtained DOS profile, trap emission prefactors and activation energy were extracted from temperature dependent capacitance-frequency measurements, while doping, Fermi energy, built-in voltage, and energy levels of the defects were extracted from capacitance-voltage measurements. We identified that the lower energy band—misinterpreted in literature as a defect distribution—stems from free carrier response. The higher energy defect distribution band for regio-random P3HT was an order of magnitude higher than region-regular P3HT, thus stemming from morphological disorder. Impedance spectroscopy was also employed for further comparison of the two P3HT species.
A comparison of the sequences in an internally transcribed spacer (ITS) 1 region of rDNA between clonally regenerated A.vera and same species in Japan, USA and Egypt revealed the presence of two types of nucleotide sequences, 252 and 254 bps. Based on the findings in the ITS 1 region, A.vera having 252 and 254 bps clearly showed a stable sequence similarity, suggesting high conversation of the base peak sequence in the ITS 1 region. However, frequent base substitutions in the 252 bps samples leaves that came from callus tissue and micropropagated plants were observed around the regions of nucleotide positions 66, 99 and 199-201. The minor deviation in clonally regenerated A.vera may be due to the stage of regeneration and cell specification in cases of the callus tissue. In the present study, the base peak sequence of the Its 1 region of rDNA was adopted as a molecular marker for differentiating A.vera plants from geographically distributed and clonally regenerated A.vera plants and it was suggested that the base peak substitutions in the ITS 1 region may arise from the different nutritional and environmental factors in cultivation and plant growth stages. (author)
Organic photovoltaics (OPVs) are regarded as promising for solar-electric conversion with steadily improving power conversion efficiencies. For further progress, it is crucial to understand and mitigate defect states (traps) residing in the band-gap of OPV materials. In this work, using capacitance measurements, we analyzed two major bands in the density of states (DOS) energy spectra of defects in poly(3-hexylthiophene) (P3HT); regio-regular and regio-random species of P3HT were compared to elucidate the role of morphological disorder. To accurately interpret the obtained DOS profile, trap emission prefactors and activation energy were extracted from temperature dependent capacitance-frequency measurements, while doping, Fermi energy, built-in voltage, and energy levels of the defects were extracted from capacitance-voltage measurements. We identified that the lower energy band—misinterpreted in literature as a defect distribution—stems from free carrier response. The higher energy defect distribution band for regio-random P3HT was an order of magnitude higher than region-regular P3HT, thus stemming from morphological disorder. Impedance spectroscopy was also employed for further comparison of the two P3HT species
Campo, Lorenzo; Castelli, Fabio; Caparrini, Francesca
2010-05-01
distributed model developed at the Department of Civil and Environmental Engineering of the University of Florence. Discussion on the comparisons between the effectiveness of the different algorithms on different cases of study on Central Italy basins is provided.
Broadening the Participation of Native Americans in Earth Science
Bueno Watts, Nievita
Climate change is not a thing of the future. Indigenous people are being affected by climate changes now. Native American Earth scientists could help Native communities deal with both climate change and environmental pollution issues, but are noticeably lacking in Earth Science degree programs. The Earth Sciences produce the lowest percentage of minority scientists when compared with other science and engineering fields. Twenty semi-structured interviews were gathered from American Indian/ Alaska Native Earth Scientists and program directors who work directly with Native students to broaden participation in the field. Data was analyzed using qualitative methods and constant comparison analysis. Barriers Native students faced in this field are discussed, as well as supports which go the furthest in assisting achievement of higher education goals. Program directors give insight into building pathways and programs to encourage Native student participation and success in Earth Science degree programs. Factors which impede obtaining a college degree include financial barriers, pressures from familial obligations, and health issues. Factors which impede the decision to study Earth Science include unfamiliarity with geoscience as a field of study and career choice, the uninviting nature of Earth Science as a profession, and curriculum that is irrelevant to the practical needs of Native communities or courses which are inaccessible geographically. Factors which impede progress that are embedded in Earth Science programs include educational preparation, academic information and counseling and the prevalence of a Western scientific perspective to the exclusion of all other perspectives. Intradepartmental relationships also pose barriers to the success of some students, particularly those who are non-traditional students (53%) or women (80%). Factors which support degree completion include financial assistance, mentors and mentoring, and research experiences. Earth scientists
N2-broadening coefficients of methyl chloride at room temperature
Methyl chloride is of interest for atmospheric applications, since this molecule is directly involved in the catalytic destruction of ozone in the lower stratosphere. In a previous work [Bray et al. JQSRT 2011;112:2446], lines positions and intensities of self-perturbed 12CH335Cl and 12CH337Cl have been studied into details for the 3.4 μm spectral region. The present work is focused on measurement and calculation of N2-broadening coefficients of the 12CH335Cl and 12CH337Cl isotopologues. High-resolution Fourier Transform spectra of CH3Cl-N2 mixtures at room-temperature have been recorded between 2800 and 3200 cm-1 at LADIR (using a classical source) and between 47 and 59 cm-1 at SOLEIL (using the synchrotron source on the AILES beamline). 612 mid-infrared transitions of the ν1 band and 86 far-infrared transitions of the pure rotational band have been analyzed using a multispectrum fitting procedure. Average accuracy on the deduced N2-broadening coefficients has been estimated to 5% and 10% in the mid- and far-infrared spectral regions, respectively. The J- and K-rotational dependences of these coefficients have been observed in the mid-infrared region and then a simulation has been performed using an empirical model for 0≤J≤50, K≤9. The 12CH335Cl-N2 line widths for 0≤J≤50 and K≤10 of the ν1 band and for 55≤J≤67 and K≤15 of the pure rotational band have been computed using a semi-classical approach involving exact trajectories and a real symmetric-top geometry of the active molecule. Finally, a global comparison with the experimental and theoretical data existing in the literature has been performed. Similar J- and K-rotational dependences have been appeared while no clear evidence for any vibrational or isotopic dependences have been pointed out.
LBQ2D, Extending the Line Broadened Quasilinear Model to TAE-EP Interaction
Ghantous, Katy; Gorelenkov, Nikolai; Berk, Herbert
2012-10-01
The line broadened quasilinear model was proposed and tested on the one dimensional electrostatic case of the bump on tailfootnotetextH.L Berk, B. Breizman and J. Fitzpatrick, Nucl. Fusion, 35:1661, 1995 to study the wave particle interaction. In conventional quasilinear theory, the sea of overlapping modes evolve with time as the particle distribution function self consistently undergo diffusion in phase space. The line broadened quasilinear model is an extension to the conventional theory in a way that allows treatment of isolated modes as well as overlapping modes by broadening the resonant line in phase space. This makes it possible to treat the evolution of modes self consistently from onset to saturation in either case. We describe here the model denoted by LBQ2D which is an extension of the proposed one dimensional line broadened quasilinear model to the case of TAEs interacting with energetic particles in two dimensional phase space, energy as well as canonical angular momentum. We study the saturation of isolated modes in various regimes and present the analytical derivation and numerical results. Finally, we present, using ITER parameters, the case where multiple modes overlap and describe the techniques used for the numerical treatment.
Kuriki, Satoshi
2010-01-01
Let $A$ be a real skew-symmetric Gaussian random matrix whose upper triangular elements are independently distributed according to the standard normal distribution. We provide the distribution of the largest singular value $\\sigma_1$ of $A$. Moreover, by acknowledging the fact that the largest singular value can be regarded as the maximum of a Gaussian field, we deduce the distribution of the standardized largest singular value $\\sigma_1/\\sqrt{\\mathrm{tr}(A'A)/2}$. These distributional results are utilized in Scheff\\'{e}'s paired comparisons model. We propose tests for the hypothesis of subtractivity based on the largest singular value of the skew-symmetric residual matrix. Professional baseball league data are analyzed as an illustrative example.
Stark broadening of the 1640- and 4686-A lines of ionized helium
The Stark-broadened profiles of the 1640- and 4686-A lines of ionized helium have been calculated using an approximation to the electron broadening operator in the unified classical-path theory of Smith, Vidal, and Cooper. The approximation is such that the results reproduce the time-ordered impact-theory results in the line center, and the ionized-radiator quasistatic results in the far wings. Sample calculations at n/sub e/ = 10/sup 17/ cm/sup -3/ and T = 40 000 degreeK are found to give significantly more narrow profiles than the corresponding modified-impact-theory results because of a different treatment of the lower-state interaction. Indirect comparison with experiment indicates that the calculated lines are too narrow, but it is expected that the inclusion of neglected effects of ion dynamics and inelastic collisions would improve agreement
Effect of nuclear motion on spectral broadening of high-order harmonic generation.
Yuan, Xiaolong; Wei, Pengfei; Liu, Candong; Ge, Xiaochun; Zheng, Yinghui; Zeng, Zhinan; Li, Ruxin
2016-04-18
High-order harmonic generation (HHG) in molecular targets is experimentally investigated in order to reveal the role of the nuclear motion played in the harmonic generation process. An obvious broadening in the harmonic spectrum from the H2 molecule is observed in comparison with the harmonic spectrum generated from other molecules with relatively heavy nuclei. We also find that the harmonic yield from the H2 molecule is much weaker than the yield from those gas targets with the similar ionization potentials, such as Ar atom and N2 molecule. The yield suppression and the spectrum broadening of HHG can be attributed to the vibrational motion of nuclear induced by the driving laser pulse. Moreover, the one-dimensional (1D) time-dependent Schrödinger equation (TDSE) with the non-Born-Oppenheimer (NBO) treatment is numerically solved to provide a theoretical support to our explanation. PMID:27137258
We have observed spectral broadening in the pulsed output of a Quantronix model 4217 modelocked and Q-switched Nd:YLF oscillator. When Q-switched, the 76-1MHz oscillator produces a nearly gaussian train of pulses with a total energy of 3 mJ and a duration of ∼300 ns. Between Q-switch cycles the CW-pumped oscillator lases at a low level to enable a circulating modelocked pulse to reach steady-state transform-limited conditions. With a 1-mm intracavity etalon the steady-state modelocked pulsewidth is 150 ps and the oscillating bandwidth is 3 GHz. Measurements show that at the peak of the Q-switched train the modelocked pulse bandwidth is broadened to 11 GHz, We attribute the altered spectrum to self-phase modulation (SPM) of the circulating pulse in the 3.8-cm long acousto-optic quartz modulators. SPM has been recognized as a potential problem in this type of oscillator however we did not expect to find it in a commercial product and its occurrence in the modulators rather than the rod was a surprise. Analysis of the cavity mode has determined that the spot size is small at the ends of the cavity where the modulators are located. A large mode volume in the rod coupled with a relatively small nonlinear coefficient makes intensity-dependent: phase shifts there negligible by comparison. Since the effects of SPM in this type of oscillator are not well-documented we developed a numerical model and used it to examine the spectral evolution of the circulating modelocked pulse after Q-switching. The model incorporates a rod with gain, two passive quartz blocks with nonlinear refractive index for simulating nonlinear propagation in the modulators, a time-dependent shutter to simulate the active modelocker, an etalon, and distributed Fresnel losses. The spectra that we calculate are in good agreement with that observed, confirming the source of the broadening. The oscillator has been redesigned to increase the mode size in the modulators and eliminate the SPM
Pressure broadening and shift of K D1 and D2 lines in the presence of 3He and 21Ne
Li, Rujie; Li, Yang; Jiang, Liwei; Quan, Wei; Ding, Ming; Fang, Jiancheng
2016-06-01
Due to the collisions with alkali-metal atoms, the buffer gases used in spin-exchange optical pumping systems induce a broadening of spectral profiles and a shift in the resonance frequency. Here we report the pressure broadening and shift rates of K D 1 and D 2 lines in the presence of 21Ne for the first time and values for 3He have been reinvestigated by means of laser absorption spectroscopy. We have also examined the temperature dependence of these collisional effects in a range of 435-458 K. A comparison for the broadening and shift rates to those of other isotopes, 4He and 20Ne, is presented.
Atsushi Komemushi
2012-01-01
Full Text Available Purpose. To assess differences in dose distribution of a vertebral body injected with bone cement as calculated by radiation treatment planning system (RTPS and actual dose distribution. Methods. We prepared two water-equivalent phantoms with cement, and the other two phantoms without cement. The bulk density of the bone cement was imported into RTPS to reduce error from high CT values. A dose distribution map for the phantoms with and without cement was calculated using RTPS with clinical setting and with the bulk density importing. Actual dose distribution was measured by the film density. Dose distribution as calculated by RTPS was compared to the dose distribution measured by the film dosimetry. Results. For the phantom with cement, dose distribution was distorted for the areas corresponding to inside the cement and on the ventral side of the cement. However, dose distribution based on film dosimetry was undistorted behind the cement and dose increases were seen inside cement and around the cement. With the equivalent phantom with bone cement, differences were seen between dose distribution calculated by RTPS and that measured by the film dosimetry. Conclusion. The dose distribution of an area containing bone cement calculated using RTPS differs from actual dose distribution.
Purpose. To assess differences in dose distribution of a vertebral body injected with bone cement as calculated by radiation treatment planning system (RTPS) and actual dose distribution. Methods. We prepared two water-equivalent phantoms with cement, and the other two phantoms without cement. The bulk density of the bone cement was imported into RTPS to reduce error from high CT values. A dose distribution map for the phantoms with and without cement was calculated using RTPS with clinical setting and with the bulk density importing. Actual dose distribution was measured by the film density. Dose distribution as calculated by RTPS was compared to the dose distribution measured by the film dosimetry. Results. For the phantom with cement, dose distribution was distorted for the areas corresponding to inside the cement and on the ventral side of the cement. However, dose distribution based on film dosimetry was undistorted behind the cement and dose increases were seen inside cement and around the cement. With the equivalent phantom with bone cement, differences were seen between dose distribution calculated by RTPS and that measured by the film dosimetry. Conclusion. The dose distribution of an area containing bone cement calculated using RTPS differs from actual dose distribution
Barthes, Laurent; Mallet, Cécile
2010-05-01
fragments droplets produced when small drops and large drops collide is overestimate. As new parameterization of LL82 is not possible due to the lack of new sufficient large experimental dataset, we have simply tried in the present study to 'compensate' the problem previously mentioned by replacing the coalescence/breakup model proposed in LL82 by another one in which the breakup process is less dominant. In order to evaluate the relevance of this modification, some of the DSD parameters such as slope, mean volume diameter, and relation between moments are calculated, and comparisons with experimental DSD are made. Simulations at equilibrium lead to a DSD tail with a slope of 23 cm-1 and a mean volume diameter equal to 2.5 mm. These values are in good agreements with experimental data. Similarly, the linear relationship between No* and the rainfall rate is also in good agreement. In the last part, the modified parameterization is then used to study the evolution of an initially gamma-like DSD in a 1D vertical rain shaft. References Barros, A. P., O. P. Prat, P. Shrestha, F. Y. Testik, and L. F. Bliven, 2008. Revisiting Low and List (1982): evaluation of raindrop collision using laboratory observations and modeling. Journal of the Atmospheric Sciences. Vol. 65(9), pp. 2983-2993. Hu, Z., and R. C. Srivastava: 1995: Evolution of raindrop size distribution by coalescence, breakup, and evaporation: Theory and observations. J. Atmos. Sci., 52, 1761-1783. Low, T. B. and R. List, 1982a: Collision, coalescence, and breakup of raindrops. Part I: Experimentally established coalescence efficiencies and fragment size distributions in breakup. J. Atmos. Sci., 39, 1591-1606. ___ 1982b: Collision, coalescence, and breakup of raindrops. Part II: Parameterization of fragment size distributions. J. Atmos. Sci., 39, 1607-1618. McFarquhar, G. M, 2004: A new representation of collision-induced breakup of raindrops and its implications for the shapes of raindrop size distributions, J. Atmos. Sci
abo-cross: Hydrogen broadening cross-section calculator
Barklem, P. S.; Anstee, S. D.; O'Mara, B. J.
2015-07-01
Line broadening cross sections for the broadening of spectral lines by collisions with neutral hydrogen atoms have been tabulated by Anstee & O'Mara (1995), Barklem & O'Mara (1997) and Barklem, O'Mara & Ross (1998) for s-p, p-s, p-d, d-p, d-f and f-d transitions. abo-cross, written in Fortran, interpolates in these tabulations to make these data more accessible to the end user. This code can be incorporated into existing spectrum synthesis programs or used it in a stand-alone mode to compute line broadening cross sections for specific transitions.
Temporal broadening of pulsed waves propagating through turbulent media
XU; Zhengwen(许正文); WU; Jian(吴健); HUO; Wenping(霍文平); WU; Zhensen(吴振森)
2003-01-01
Pulse signals, propagating through a turbulent medium such as the ionosphere, can be distorted by dispersion and scattering from both the background medium and irregularities embedded in. Thus, the mean square pulse width is changed, and temporal broadening is introduced. We carry out a study on the temporal broadening with theoretical analyses and numerical simulations by using an analytical solution of two-frequency mutual coherence function obtained recently by iteration. As a case of study, pulse broadening is investigated in detail in trans-ionospheric propagation. Results show that most contributions are mainly from the dispersion of the background ionosphere and scattering effects of electron density irregularities in most cases.
Momentum broadening in unstable quark-gluon plasma
Carrington, M E; Schenke, B
2016-01-01
Quark-gluon plasma produced at the early stage of ultrarelativistic heavy ion collisions is unstable, if weakly coupled, due to the anisotropy of its momentum distribution. Chromomagnetic fields are spontaneously generated and can reach magnitudes much exceeding typical values of the fields in equilibrated plasma. We consider a high energy test parton traversing an unstable plasma that is populated with strong fields. We study the momentum broadening parameter $\\hat q$ which determines the radiative energy loss of the test parton. We develop a formalism which gives $\\hat q$ as the solution of an initial value problem, and we focus on extremely oblate plasmas which are physically relevant for relativistic heavy ion collisions. The parameter $\\hat q$ is found to be strongly dependent on time. For short times it is of the order of the equilibrium value, but at later times $\\hat q$ grows exponentially due to the interaction of the test parton with unstable modes and becomes much bigger than the value in equilibri...
Dynamic Stark broadening as the Dicke narrowing effect
Calisti, A.; Mossé, C.; Ferri, S.; Talin, B.; Rosmej, F.; Bureyeva, L. A.; Lisitsa, V. S.
2010-01-01
A very fast method to account for charged particle dynamics effects in calculations of spectral line shape emitted by plasmas is presented. This method is based on a formulation of the frequency fluctuation model (FFM), which provides an expression of the dynamic line shape as a functional of the static distribution of frequencies. Thus, the main numerical work rests on the calculation of the quasistatic Stark profile. This method for taking into account ion dynamics allows a very fast and accurate calculation of Stark broadening of atomic hydrogen high- n series emission lines. It is not limited to hydrogen spectra. Results on helium- β and Lyman- α lines emitted by argon in microballoon implosion experiment conditions compared with experimental data and simulation results are also presented. The present approach reduces the computer time by more than 2 orders of magnitude as compared with the original FFM with an improvement of the calculation precision, and it opens broad possibilities for its application in spectral line-shape codes.
Probing Transverse Momentum Broadening in Heavy Ion Collisions
Mueller, A H; Xiao, Bo-Wen; Yuan, Feng
2016-01-01
We study the dijet azimuthal de-correlation in relativistic heavy ion collisions as an important probe of the transverse momentum broadening effects of a high energy jet traversing the quark-gluon plasma. We take into account both the soft gluon radiation in vacuum associated with the Sudakov logarithms and the jet P_T-broadening effects in the QCD medium. We find that the Sudakov effects are dominant at the LHC, while the medium effects can play an important role at RHIC energies. This explains why the LHC experiments have not yet observed sizable P_T-broadening effects in the measurement of dijet azimuthal correlations in heavy ion collisions. Future investigations at RHIC will provide a unique opportunity to study the P_T-broadening effects and help to pin down the underlying mechanism for jet energy loss in a hot and dense medium.
Calculation of the Doppler broadening function using Fourier analysis
An efficient and precise method for calculation of Doppler broadening function is very important to obtain average group microscopic cross sections, self shielding factors, resonance integrals and others reactor physics parameter. In this thesis two different methods for calculation of Doppler broadening function and interference term will be presented. The main method is based on a new integral form for Doppler broadening function ψ(x,ζ) which gives a mathematical interpretation of the approximation proposed by Bethe and Placzek, as the convolution of the Lorentzian function with a Gaussian function. This interpretation besides leading to a new integral form for ψ(x,ζ), enables to obtain a simple analytic solution for the Doppler broadening function. (author)
Goldhirsh, Julius; Gebo, Norman; Rowland, John
1988-01-01
In this effort are described cumulative rain rate distributions for a network of nine tipping bucket rain gauge systems located in the mid-Atlantic coast region in the vicinity of the NASA Wallops Flight Facility, Wallops Island, Virginia. The rain gauges are situated within a gridded region of dimensions of 47 km east-west by 70 km north-south. Distributions are presented for the individual site measurements and the network average for the year period June 1, 1986 through May 31, 1987. A previous six year average distribution derived from measurements at one of the site locations is also presented. Comparisons are given of the network average, the CCIR (International Radio Consultative Committee) climatic zone, and the CCIR functional model distributions, the latter of which approximates a log normal at the lower rain rate and a gamma function at the higher rates.
Self-phase-modulation induced spectral broadening in silicon waveguides
Boyraz, Ozdal; Indukuri, Tejaswi; Jalali, Bahram
2004-03-01
The prospect for generating supercontinuum pulses on a silicon chip is studied. Using ~4ps optical pulses with 2.2GW/cm2 peak power, a 2 fold spectral broadening is obtained. Theoretical calculations, that include the effect of two-photon-absorption, indicate up to 5 times spectral broadening is achievable at 10x higher peak powers. Representing a nonlinear loss mechanism at high intensities, TPA limits the maximum optical bandwidth that can be generated.
Broadening of Transverse Momentum of Partons Propagating through a Medium
Johnson, M. B.; Kopeliovich, B. Z.; Tarasov, A. V.
2000-01-01
Broadening of the transverse momentum of a parton propagating through a medium is treated using the color dipole formalism, which has the advantage of being a well developed phenomenology in deep-inelastic scattering and soft processes. Within this approach, nuclear broadening should be treated as color filtering, i.e. absorption of large-size dipoles leading to diminishing (enlarged) transverse separation (momentum). We also present a more intuitive derivation based on the classic scattering...
Narrowing of EIT resonance in a Doppler Broadened Medium
Javan, Ali; Kocharovskaya, Olga; Lee, Hwang; Scully, Marlan O.
2001-01-01
We derive an analytic expression for the linewidth of EIT resonance in a Doppler broadened system. It is shown here that for relatively low intensity of the driving field the EIT linewidth is proportional to the square root of intensity and is independent of the Doppler width, similar to the laser induced line narrowing effect by Feld and Javan. In the limit of high intensity we recover the usual power broadening case where EIT linewidth is proportional to the intensity and inversely proporti...
Dhartiben B. Kapadiya; Darshna B. Prajapati; Amit Kumar Jain; Bhavbhuti M. Mehta; Vijaykumar B. Darji; Kishorkumar D. Aparnathi
2016-01-01
Aim: The study was undertaken to find out the gross composition, nitrogen distribution, and selected mineral content in Surti goat milk, and its comparison was made between cow and buffalo milk. Materials and Methods: Goat milk samples of Surti breed and buffalo milk samples were collected during the period from July to January 2014 at Reproductive Biology Research Unit, Anand Agricultural University (AAU), Anand. Cow milk samples of Kankrej breed were collected from Livestock Research Sta...
Jonasdottir, Sigrun; Koski, Marja
2011-01-01
Comparison of abundance, vertical distribution and reproduction of the cousin species, the boreal Calanus finmarchicus and temperate Calanus helgolandicus was carried out on four cruises in July and August north of the Dogger Bank, North Sea. During this period, the water column was highly strati...... ecosystem longer than previously thought, and with warmer surface temperatures retreat to cooler, deeper waters utilizing the deep chlorophyll maximum. This implies that C. finmarchicus cannot be reliably sampled with the Continuous Plankton Recorder during summer....
Processing of doppler broadening spectra of positron annihilation radiation and its application
An unfolding method to obtain intrinsic distributions of positron annihilation radiation from Doppler broadening spectra by means of an iterative method is described. The intrinsic distribution can be fitted into a Gaussian function and an invert parabola function. Electron momentum distribution and Fermi energy can be calculated. Positron annihilation spectra for 13 materials were analyzed. Their momentum distribution and Fermi energy were obtained. The results show that electron momentum distributions for various materials are different and experimental values of Fermi energy for various materials are consistent with theoretical ones. The study on amorphous and crystalline Fe-Si-B alloys indicates that momentum distributions are almost the same, while there is a small difference on Fermi energy
Comparison of plutonium distribution and radiation dose received by mouse and dog testis
Estimation of the potential risk of genetic damage to the human testis from internally deposited 239Pu is mainly based on rodent data. Because of species-dependent variations in ratios of testis to body weight and in seminiferous tubule to interstitial tissue volume, an interspecies comparison of the concentration and microdistribution of 239Pu in the mouse and dog testis was carried out to estimate the radiation dose delivered to spermatogonial stem cells. Twenty-seven B6CF, and fifteen C3Hx101 male mice received an intravenous injection of 10 μCi/kg of monomeric 239Pu-citrate; nine beagle dogs received 0.3 μCi/kg. The animals were sacrificed 6 hrs, 6 days, and 100 days later, and testes were taken for 239Pu analyses and quantitative auto-radiography. The testicular Pu burdens in the B6CF1 mice and in the dogs dropped from 0.16% and 0.14% of the injected dose (ID), respectively, at 6 hours, to 0.05% ID and 0.02% ID, respectively, at 6 days, and remained constant thereafter. The testicular Pu burden in the C3Hx101 mice at 6 days was 30% higher than in the B6CF1 mice; but by 100 days the burdens in the two mouse strains were nearly equal. The ratio of testis to body weight declined 19% by 100 days in B6CF1 mice and 23% in C3Hx101 mice; this ratio remain unchanged in the dogs. Based on autoradiographic track counts, about 95% of the 239Pu in the dog testes and about 88% of the 239Pu in the testes of both mouse strains was associated with interstitial and peritubular cells. Because of this preferential distribution of 239Pu, the radiation dose received by spermatogonial stem cells is calculated to be 3.5 times higher in the mouse and 4.5 times higher in the dog than the average dose to the whole testis. Implications of these data for man will be discussed. (author)
Plasma motions and non-thermal line broadening in flaring twisted coronal loops
Gordovskyy, Mykola; Browning, Philippa
2015-01-01
Observation of coronal EUV spectral lines offers an opportunity to evaluate the thermal structure and flows in flaring atmospheres. This, in turn, can be used to estimate the partitioning between the thermal and kinetic energies released in flares. Our aim is to forward-model large-scale (50-10000 km) velocity distributions in order to interpret non-thermal broadening of different spectral EUV lines observed in flares. The developed models allow us to understand the origin of the observed spectral line shifts and broadening, and link these features to particular physical phenomena in flaring atmospheres. We use ideal MHD to derive unstable twisted magnetic fluxtube configurations in a gravitationally-stratified atmosphere. The evolution of these twisted fluxtubes is followed using resistive MHD, with anomalous resistivity depending on the local density and temperature. The model also takes into account the thermal conduction and radiative losses. The model allows us to evaluate average velocities and velocity...
Analysis of pressure-broadened ozone spectra in the 3 micron region
Prochaska, Eleanor S.
1991-01-01
This work involves the analysis of a series of McMath Fourier Transform Infrared (FTIR) spectra of ozone broadened by mixing with air (four different pressures), nitrogen (three pressures), or oxygen (three pressures). Each spectrum covers the region from 2396 to 4057 cm(-1). This study focused on the 3 sub nu sub 3 band in t 3000 to 3060 cm(-1). The band is analyzed by first dividing its region into small intervals containing a few well isolated absorption lines of reasonable intensity. Each of these small intervals is fit by multiple iterations of the nonlinear least squares program until residuals (the difference between calculated and observed spectrum, as a percent of the strongest intensity in the interval) are minimized to a reasonable value which corresponds to the noise level of the measured spectrum. Position, intensity, and half-width are recorded for later analysis. From the measured half-widths, a pressure broadening coefficient was determined for each absorption line. Pressure shifts were determined by comparing observed line positions in the spectra of the diluted ozone samples to tabulated line positions determined from spectra of pure gas samples. Comparisons to other work on ozone indicate that the broadening and shift coefficients determined in this study are consistent with those determined in other spectral regions.
Application of Doppler broadening of neutron-induced prompt γ-rays to analytical sciences
Activation analysis can measure γ-rays released from excited state of nucleus of nuclear reaction. The energy, sharp and width of γ-ray are not affected by the sample states. However, 7*Li from 10B(n,α)7*Li is an exception. It moderates by interaction with atoms in the course of motion and shows Doppler broadening, of which order depended on the chemical and physical state of sample. The principle of Doppler broadening is explained. The examples of spectra of Doppler broadening of 478 keV-prompt gamma ray are shown. The slowing down constant D (DLSS) of 7*Li is estimated by use of LSS (Lindhart, Scharff and Schiott) theory. As three application examples, boron in the natural cherry leaf, bean and yellow sand were characterized. The line shapes of green leaf and brown leaf were different. The former value was the same as the boric acid solution and the latter the solid boron. D value of yellow sand resembled the value estimated from the composition of aluminosilicate. Accordingly, boron is thought to be exchanged with aluminum. The future problems such as comparison D with DLSS, behavior of 7*Li generated from the smaller size sample with boron than the range and observation of other reaction are discussed. (S.Y.)
Sobol, Eyal; Bialer, Meir
2004-03-01
Pharmacokinetic textbooks state that the (apparent) volume of distribution based on drug concentration in plasma (V or Vbeta) is always greater than the volume of distribution (apparent) under steady state conditions (Vss), but do not provide a general model-independent mathematical proof. Wagner's mathematical comparison between Vbeta and Vss is based on microscopic rate constants of either specific models and is restricted solely to the two-compartment open body model. Nakashima and Benet utilizing a model-dependent approach showed a mathematical relationship between Vbeta and Vss for a multicompartment model, but again by using microscopic model constants. The limitation of these two above mentioned mathematical comparisons is the necessity of knowledge of the model's structure and its microscopic rate constants. The present article describes a new non-compartmental, model-independent, general mathematical proof for Vbeta to be always greater than Vss. This new method does not require any knowledge of microscopical rate constants and is based solely on an exponentially decreasing function, which is the common way to describe drug disposition following i.v. bolus. PMID:14872558
Measurement of pressure-broadening parameters for the CO-He system at 4 K
A technique has been developed to observe collisions in a regime where the rotational energy-level separation is greater than the thermal energy. Pressure-broadening parameters of trace quantities of CO, thermalized by collisions with helium at 4 K, were measured and found to be 10.1 and 11.2 MHz/Torr half width at half maximum for the J = 0-1 and J = 1-2 transitions, respectively. At 4 K only a small number of collision channels are energetically available and comparisons between experiment and theory are facilitated
Correlation effects in the theory of combined Doppler and pressure broadening. I - Classical theory
Ward, J.; Cooper, J.; Smith, E. W.
1974-01-01
An investigation is conducted of the combined effects of radiator-perturber collisions and radiator translational motion in the context of foreign gas broadening of optical transitions in neutral radiators. Questions concerning the speed-dependent collision frequency are considered and aspects of general theory are explored, taking into account the correlation function, the ensemble average, and the kinetic equation formalism. An elementary solution is discussed along with a one-perturber approximation, inverse power law model calculations, and a comparison with the Voigt profile.
Full text: The purpose of this work is the evaluation and comparison of the dose rate distributions around a 252Cf Applicator Tube (AT) and 192Ir LDR sources. The dosimetric parameters were determined for both sources according to the updated AAPM TG-43U1 protocol. The calculations were performed using the Monte Carlo N-particle MCNP code, version 5C. To validate the results of this study, they were compared to experimental and analytical dosimetric data available in the literature for similar source configurations. After validation, the Monte Carlo computer code was applied to investigate the difference between dose rate distributions around the two brachytherapy sources, with the purpose of comparing their efficiency in treatment. The data so obtained also provide further information about spatial dose distributions and are important for detailed treatment planning with 252 Cf or 192Ir LDR sources for interstitial and intracavitary therapy
Flynn, A. A.; Green, A. J.; Boxer, G.; Pedley, R. B.; Begent, R. H. J.
1999-07-01
Image registration is a powerful tool for correlating functional images with images of anatomical structure. This facilitates more accurate quantitation of regional radiopharmaceutical uptake. Similarly, registration of images of radiolabelled antibody distribution, in tissue sections, with the equivalent histological images allows the comparison and measurement of radiopharmaceutical distribution with morphological structure. The images used were obtained by storage phosphor plate technology, for the radiopharmaceutical distribution, and by digitization of the stained histological sections. Here we compare four fully automatic registration techniques and one manual technique in terms of their spatial accuracy. We have found that there was no difference in accuracy between cross-correlation, minimization of variance and mutual information. These techniques were more accurate than principal axes and the manual technique. However, minimization of variance and mutual information were more time-consuming than the other methods. Consequently, cross-correlation is the method of choice for automatic registration of large numbers of these image pairs.
Broadening Participation in Citizen Science Campaigns
Pandya, R. E.
2011-12-01
While successful citizen-science campaigns have demonstrable effectiveness in engaging their participants in scientific projects, and research suggests that participants learn about both scientific processes and content, many campaigns struggle to engage participants from communities that have been historically under-represented in science. This is both puzzling and unfortunate: puzzling because citizen-scientist programs are often built around phenomena that are part of many people's daily lives and unfortunate because these programs offer a new and effective approach to scientific outreach and education that could, potentially, offer new avenues to include historically underserved communities in science. This poster will explore the demographics of several well-known citizen science programs, compare them to national trends, and use this comparison to suggest goals for diversifying citizen-science participation. It will review research on minority participation in formal and informal geoscience and science education programs to identify barriers to broader participation and offer some strategies for diversifying citizen science programs. It will highlight participatory research methodologies as used in resource conservation and public health, and explore their relevance to citizen science program. The overall goal of the poster is not to suggest a singular answer or even promote best practices, since much of what works well is likely to be place-based and context dependence. Instead, we seek to raise questions, offer approaches and spark a dialogue among citizen-science practitioners that will encourage new approaches and ultimately result in broader engagement in citizen-science campaigns.
Collet, Lila; Beevers, Lindsay; Prudhomme, Christel
2016-04-01
Floods are the most common and widely distributed natural risk to life and property worldwide, causing over £6B worth of damage to the UK since 2000. Climate projections are predicted to result in the increase of UK properties at risk from flooding. It thus becomes urgent to assess the possible impact of these changes on extreme high flows in particular, and evaluate the uncertainties related to these projections. This paper aims to assess the changes in extreme runoff for the 1:100 year return period event across Great Britain as a result of climate change. It is based on the Future Flow database and analyses daily runoff over 1961-2098 for 281 gauging stations. The Generalized Extreme Value (GEV) and Generalized Pareto (GP) distribution functions are automatically fitted for 11 climate-change ensembles over the baseline (1961-1990) and the 2080s (2069-2098) for each gauging station. The analysis evaluates the uncertainty related to the Extreme Value (EV) distributions, and the uncertainty related to the climate model parameterization. Then it assesses return levels with combined uncertainties across Great Britain for both EV distributions. Ultimately, this work gives a national picture of extreme flows assessed by the two methods and allows a direct comparison between them. Results show that the GP distribution computes higher runoff estimates than the GEV distribution. Generally, the uncertainties associated with both distributions are similar, but the GP computes significantly higher uncertainties for stations in the south and southeast of England. From the baseline to the 2080s horizon, the GEV distribution shows variable runoff trends across Great Britain, while the GP distribution shows an increasing trend of return level estimate and uncertainties, especially in the northeast and southeast of England. The lowest climate model and extreme value uncertainty is generally seen across the west coast of Great Britain. In terms of uncertainty, with the GEV
Stochastic Comparisons of Generalized Gamma Distribution%变换广义 Gamma 分布的随机比较
王丰效
2016-01-01
The generalized Gamma distribution was a kind of important probability distribution .The stochastic comparisons of the transformation generalized Gamma distribution were discussed .Two independent random variables that come from transform gamma distribution were compared in the usual stochastic order and likelihood ratio order .The relationship between the parameters of the cumulative distribution functions was derived when the random variables had the orders above .The relationship of the order statistics that come from two groups of independent transform gamma distribution random variables was given .%广义Gamma分布是一类重要的概率分布，讨论变换广义Gamma分布的随机比较。给出了两个相互独立但不同分布的变换广义Gamma分布随机变量满足随机序时其分布所含参数间的相应关系。也给出了两组相互独立但不同分布的变换广义Gamma分布随机变量次序统计量之间的随机序关系。
Poljanc, K
2000-01-01
The use of high precision radiation with particles (protons and ions) allows the radiation of tumors near risk organs and immedicable tumors. The aim of this work is the comparison between normal tissue complication probability for craniocerebral tumors of children and youth during simulation of photontherapy and proton therapy. The multivariate analysis gives the possibility to determine the tolerance dose for certain organs.
Comparison of measured and simulated fast ion velocity distributions in the TEXTOR tokamak
Moseev, Dmitry; Meo, Fernando; Korsholm, Søren Bang; Koskela, T; Albergante, M; Asunta, O; Bindslev, Henrik; Bürger, A; Furtula, Vedran; Kantor, M Yu; Leipold, Frank; Michelsen, Poul; Nielsen, Stefan Kragh; Salewski, Mirko; Schmitz, O; Stejner Pedersen, Morten; Westerhof, E
2011-01-01
Here we demonstrate a comprehensive comparison of collective Thomson scattering (CTS) measurements with steady-state Monte Carlo simulations performed with the ASCOT and VENUS codes. The measurements were taken at a location on the magnetic axis as well as at an off-axis location, using two proje...
Broadening of Transverse Momentum of Partons Propagating through a Medium
Johnson, M B; Tarasov, A V
2001-01-01
Broadening of the transverse momentum of a parton propagating through a medium is treated using the color dipole formalism, which has the advantage of being a well developed phenomenology in deep-inelastic scattering and soft processes. Within this approach, nuclear broadening should be treated as color filtering, i.e. absorption of large-size dipoles leading to diminishing (enlarged) transverse separation (momentum). We also present a more intuitive derivation based on the classic scattering theory of Moli\\`ere. This derivation helps to understand the origin of the dipole cross section, part of which comes from attenuation of the quark, while another part is due to multiple interactions of the quark. It also demonstrates that the lowest-order rescattering term provides an A-dependence very different from the generally accepted A^{1/3} behavior. The effect of broadening increases with energy, and we evaluate it using different phenomenological models for the unintegrated gluon density. Although the process is...
Collisional line broadening in atomic and ionic spectra
The collision broadening and shift of the resonance lines of Mg+ (the solar h and k lines), Ca+ (the solar H and K lines) and Sr+, induced by helium and argon, have been measured, together with the singlet resonance lines of the neutral species. The profiles were observed in emission from a flow lamp using a scanning Fabry-Perot interferometer and recorded digitally using a microprocessor-controlled data logging system. Broadening and shift parameters were both obtained by numerical analysis of this data. The new results are augmented by previous measurements in calcium alone and revealing trends through the three consecutive group II elements are established. The observed broadening in argon is in surprisingly good agreement with the predictions of van-der-Waals theory but the shift results do not confirm the presence of any real R-6 long range interaction. (author)
Shape of collision-broadened lines of carbon monoxide
Seleznev, A. F.; Fedoseev, G. V.; Koshelev, M. A.; Tretyakov, M. Yu.
2015-08-01
We consider lineshape of the rotational spectrum of a CO molecule under the conditions of prevailing collisional broadening. Several series of experimental data obtained at relatively high (up to 1000) signal-to-noise ratio of self-broadening and broadening by noble gases have been analyzed. We used for analysis several well known models beyond the Voigt profile. It is confirmed that the use of the Hartman-Tran profile needs certain requirements in order to obtain meaningful and unambiguous results. A simple numerical simulation is suggested to evaluate the result of the model usage for any particular set of experimental data. Parameters of the collisional line narrowing were obtained. It is shown that under the experimental conditions, deviations of the shape of the observed lines from the Voigt profile are solely due to the wind effect.
Optical coherent control in semiconductors: Fringe contrast and inhomogeneous broadening
Østergaard, John Erland; Vadim, Lyssenko; Hvam, Jørn Märcher
2001-01-01
Optical coherent control experiments in semiconductors reveal how inhomogeneous broadening must be taken into account in contrast to previous coherent control experiments in atomic and molecular systems. With spectral resolution elf the coherent control signal, the optical phases involved...... in the interplay between the homogeneous and inhomogeneous broadenings are measured. Based on these experiments, a coherent control model describing the optical fringe contrast using different detection schemes, such as photoluminescence or four-wave mixing, is established. Significant spectral modulation...... is observed in the four-wave mixing spectra as a function of phase-delay representing coherent control in the spectral domain. The spectral phase change of this modulation provides a spectroscopic tool to analyze contributions of inhomogeneous broadening to electronic resonances in semiconductor structures....
The coincidence Doppler broadening (CDB) technique in positron annihilation studies is used to study the momentum distribution of the electrons with which the positrons are annihilating. The relative momentum distribution curves of different samples become reliable under stringent stability conditions of the acquisition system. The CDB spectra were simulated by Monte Carlo method to study the effect of various instrumental parameters on the information extracted from CDB spectra. (author)
Multigroup Free-atom Doppler-broadening Approximation. Theory
Gray, Mark Girard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-11-06
Multigroup cross sections at a one target temperature can be Doppler-broadened to multigroup cross sections at a higher target temperature by matrix multiplication if the group structure suf- ficiently resolves the original temperature continuous energy cross section. Matrix elements are the higher temperature group weighted averages of the integral over the lower temperature group boundaries of the free-atom Doppler-broadening kernel. The results match theory for constant and 1/v multigroup cross sections at 618 lanl group structure resolution.
Multigroup Free-atom Doppler-broadening Approximation. Experiment
Gray, Mark Girard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-11-06
The multigroup energy Doppler-broadening approximation agrees with continuous energy Dopplerbroadening generally to within ten percent for the total cross sections of ^{1}H,^{ 56}Fe, and ^{235}U at 250 lanl. Although this is probably not good enough for broadening from room temperature through the entire temperature range in production use, it is better than any interpolation scheme between temperatures proposed to date, and may be good enough for extrapolation from high temperatures. The method deserves further study since additional improvements are possible.
Study of peak broadening effect in floor time histories
Seismic design of secondary systems such components and piping is usually carried out by using the floor motions at their support points. These floor motions can be in the form of Floor Response Spectra (FRS) or the Floor Time Histories (FTH). In order to account for the various uncertainties in generating these floor motions, these motions should be peak broadened and smoothened as per the regulatory codes. Presented here in this paper is the methodology to account for such peak broadening effect in the FTH. Results of this study have been compared with the FRS approach and various important conclusions have been arrived at based on the study
Selvam, A M
2011-01-01
Atmospheric flows exhibit self-similar fractal space-time fluctuations on all space-time scales in association with inverse power law distribution for power spectra of meteorological parameters such as wind, temperature, etc., and thus implies long-range correlations, identified as self-organized criticality generic to dynamical systems in nature. A general systems theory developed by the author visualizes the fractal fluctuations to result from the coexistence of eddy fluctuations in an eddy continuum, the larger scale eddies being the integrated mean of enclosed smaller scale eddies. The model predicts that the probability distributions of component eddy amplitudes and the corresponding variances (power spectra) are quantified by the same universal inverse power law distribution incorporating the golden mean. Atmospheric particulates are held in suspension by the vertical velocity distribution spectrum. The atmospheric particulate size spectrum is derived in terms of the model predicted universal inverse po...
Encoder power consumption comparison of Distributed Video Codec and H.264/AVC in low-complexity mode
Ukhanova, Ann; Belyaev, Eugeniy; Forchhammer, Søren
2010-01-01
This paper presents a power consumption comparison of a novel approach to video compression based on distributed video coding (DVC) and widely used video compression based on H.264/AVC standard. We have used a low-complexity configuration for H.264/AVC codec. It is well-known that motion estimati...... stated in this paper show that for current implementations of DVC these statements could be disputed from a power consumption/compression efficiency point of view when comparing to compression algorithms based on differential frame coding (with zero search radius for ME)....
Comparison of plantar pressure distribution in subjects with normal and flat feet during gait
Aluisio Otavio Vargas Avila; Patrik Felipe Nazario; João Otacilio Libardoni dos Santos
2010-01-01
The aim of this study was to determine the possible relationship between loss of thenormal medial longitudinal arch measured by the height of the navicular bone in a static situationand variables related to plantar pressure distribution measured in a dynamic situation. Elevenmen (21 ± 3 years, 74 ± 10 kg and 175 ± 4 cm) participated in the study. The Novel Emed-ATSystem was used for the acquisition of plantar pressure distribution data (peak pressure, meanpressure, contact area, and relative ...
Accelerator epithermal neutron beams produced by 7Li(p,n)7Be reactions were compared with reactor neutron beams using a fission converter (20% enriched 235U 5mm-thick plate) from view points of neutron spectrum and depth-dose distributions in a phantom. It is possible to design accelerator epithermal neutron beams having better depth-dose distributions than reactor neutron beams. (author)
Comparison of gluon flux-tube distributions for quark-diquark and quark-antiquark hadrons
Bissey, F.; Signal, A. I.; Leinweber, D. B.
2009-01-01
The distribution of gluon fields in hadrons is of fundamental interest in QCD. Using lattice QCD we have observed the formation of gluon flux tubes within 3 quark (baryon) and quark plus antiquark (meson) systems for a wide variety of spatial distributions of the color sources. In particular we have investigated three quark configurations where two of the quarks are close together and the third quark is some distance away, which approximates a quark plus diquark string. We find that the strin...
Barkana, Rennan
2002-01-01
Recently, Lanzetta et al. (2002) have measured the distribution of star formation rate intensity in galaxies at various redshifts. This data set has a number of advantages relative to galaxy luminosity functions; the effect of surface-brightness dimming on the selection function is simpler to understand, and this data set also probes the size distribution of galactic disks. We predict this function using semi-analytic models of hierarchical galaxy formation in a LCDM cosmology. We show that t...
Abe, T.; Sakurai, T; Kurata, J; Kawakami, Y; Fukunaga, T.
1996-01-01
OBJECTIVE: To examine the effects of aging and physical activity on distribution patterns in subcutaneous and visceral fat. METHODS: Distributions of subcutaneous rat mass at six segments (face and neck, forearm, upper arm, trunk, thigh, and lower leg) were determined by adipose tissue thickness measurements by B mode ultrasonogram and body surface areas. Visceral fat mass was calculated by subtracting subcutaneous fat mass from the total fat mass determined hydrodensitometrically. Measuremen...
A Performance Comparison of Tree and Ring Topologies in Distributed System
Min Huang
2005-12-19
A distributed system is a collection of computers that are connected via a communication network. Distributed systems have become commonplace due to the wide availability of low-cost, high performance computers and network devices. However, the management infrastructure often does not scale well when distributed systems get very large. Some of the considerations in building a distributed system are the choice of the network topology and the method used to construct the distributed system so as to optimize the scalability and reliability of the system, lower the cost of linking nodes together and minimize the message delay in transmission, and simplify system resource management. We have developed a new distributed management system that is able to handle the dynamic increase of system size, detect and recover the unexpected failure of system services, and manage system resources. The topologies used in the system are the tree-structured network and the ring-structured network. This thesis presents the research background, system components, design, implementation, experiment results and the conclusions of our work. The thesis is organized as follows: the research background is presented in chapter 1. Chapter 2 describes the system components, including the different node types and different connection types used in the system. In chapter 3, we describe the message types and message formats in the system. We discuss the system design and implementation in chapter 4. In chapter 5, we present the test environment and results, Finally, we conclude with a summary and describe our future work in chapter 6.
Muhamad Amin, Anang Hudaya; Khan, Asad I.
Research trends in existing event detection schemes using Wireless Sensor Network (WSN) have mainly focused on routing and localisation of nodes for optimum coordination when retrieving sensory information. Efforts have also been put in place to create schemes that are able to provide learning mechanisms for event detection using classification or clustering approaches. These schemes entail substantial communication and computational overheads owing to the event-oblivious nature of data transmissions. In this paper, we present an event detection scheme that has the ability to distribute detection processes over the resource-constrained wireless sensor nodes and is suitable for events with spatio-temporal characteristics. We adopt a pattern recognition algorithm known as Distributed Hierarchical Graph Neuron (DHGN) with collaborative-comparison learning for detecting critical events in WSN. The scheme demonstrates good accuracy for binary classification and offers low-complexity and high-scalability in terms of its processing requirements.
Wang, Huihui; Kaganovich, Igor D; Mustafaev, Alexander S
2016-01-01
Using Monte Carlo Collisions (MCC) method, we have performed simulations of ion velocity distribution functions (IVDF) taking into account both elastic collisions and charge exchange collisions of ions with atoms in uniform electric fields for argon and helium background gases. The simulation results are verified by comparison with the experiment data of the ion drift velocities and the ion transverse diffusion coefficients in argon and helium. The recently published experimental data for the first seven coefficients of the Legendre polynomial expansion of the ion energy and angular distribution functions are used to validate simulation results for IVDF. Good agreements between measured and simulated IVDFs show that the developed simulation model can be used for accurate calculations of IVDFs.
Andreas Hoffmann; Michael Zürch; Christian Spielmann
2015-01-01
In this contribution we present a comparison of the performance of spectrally broadened ultrashort pulses using a hollow-core fiber either filled with argon or sulfur hexafluoride (SF6) for demanding pulse-shaping experiments. The benefits of both gases for pulse-shaping are studied in the highly nonlinear process of high-harmonic generation. In this setup, temporally shaping the driving laser pulse leads to spectrally shaping of the output extreme ultraviolet (XUV) spectrum, where total yie...
Haixing Liu,Jing Lu,Ming Zhao∗; Yixing Yuan
2016-01-01
In order to compare two advanced multi⁃objective evolutionary algorithms, a multi⁃objective water distribution problem is formulated in this paper. The multi⁃objective optimization has received more attention in the water distribution system design. On the one hand the cost of water distribution system including capital, operational, and maintenance cost is mostly concerned issue by the utilities all the time; on the other hand improving the performance of water distribution systems is of equivalent importance, which is often conflicting with the previous goal. Many performance metrics of water networks are developed in recent years, including total or maximum pressure deficit, resilience, inequity, probabilistic robustness, and risk measure. In this paper, a new resilience metric based on the energy analysis of water distribution systems is proposed. Two optimization objectives are comprised of capital cost and the new resilience index. A heuristic algorithm, speed⁃constrained multi⁃objective particle swarm optimization ( SMPSO) extended on the basis of the multi⁃objective particle swarm algorithm, is introduced to compare with another state⁃of⁃the⁃art heuristic algorithm, NSGA⁃II. The solutions are evaluated by two metrics, namely spread and hypervolume. To illustrate the capability of SMPSO to efficiently identify good designs, two benchmark problems ( two⁃loop network and Hanoi network) are employed. From several aspects the results demonstrate that SMPSO is a competitive and potential tool to tackle with the optimization problem of complex systems.
Comparison of Distribution Models for Peakflow, Flood Volume and Flood Duration
Mohsen Salarpour
2013-06-01
Full Text Available Besides peakflow, a flood event is also characterized by other possibly mutually correlated variables. This study was aimed at exploring the statistical distribution of peakflow, flood duration and flood volume for Johor River in south of Peninsular Malaysia. Hourly data were recorded for 45 years from the Rantau Panjang gauging station. The annual peakflow was selected from the maximum flow in each water year (July-June. Five probability distributions, namely Gamma, Generalized Pareto, Beta, Pearson and Generalized Extreme Value (GEV were used to model the distribution of peakflow events. Anderson-Darling and Chi-squared goodness-of-fit tests were used to evaluate the best fit. Goodness-of-fit tests at 5% level of significance indicate that all the models can be used to model the distribution of peakflow, flood duration and flood volume. However, Generalized Pareto distribution was found to be the most suitable model when tested with the Anderson-Darling-Smirnov test and the Chi-squared test suggested that Generalized Extreme Value was the best for peakflow. The result of this research can be used to improve flood frequency analysis.
This report presents the results of an experimental study of the aerosol produced by the combustion of high-velocity molten-uranium droplets produced by the simultaneous heating and electromagnetic launch of uranium wires. These tests are intended to simulate the reduction of high-velocity fragments into aerosol in high-explosive detonations or reactor accidents involving nuclear materials. As reported earlier, the resulting aerosol consists mainly of web-like chain agglomerates. A condensation nucleus counter was used to investigate the decay of the total particle concentration due to coagulation and losses. Number size distributions based on mobility equivalent diameter obtained soon after launch with a Differential Mobility Particle Sizer showed lognormal distributions with an initial count median diameter (CMD) of 0.3 μm and a geometric standard deviation, σg of about 2; the CMD was found to increase and σg decrease with time due to coagulation. Mass size distributions based on aerodynamic diameter were obtained for the first time with a Microorifice Uniform Deposit Impactor, which showed lognormal distributions with mass median aerodynamic diameters of about 0.5 μm and an aerodynamic geometric standard deviation of about 2. Approximate methods for converting between number and mass distributions and between mobility and aerodynamic equivalent diameters are presented
Effects of target size on the comparison of photon and charged particle dose distributions
The work presented here is part of an ongoing project to quantify and evaluate the differences in the use of different radiation types and irradiation geometries in radiosurgery. We are examining dose distributions for photons using the ''Gamma Knife'' and the linear accelerator arc methods, as well as different species of charged particles from protons to neon ions. A number of different factors need to be studied to accurately compare the different modalities such as target size, shape and location, the irradiation geometry, and biological response. This presentation focuses on target size, which has a large effect on the dose distributions in normal tissue surrounding the lesion. This work concentrates on dose distributions found in radiosurgery, as opposed to those usually found in radiotherapy. 5 refs., 2 figs
Monte Carlo codes are widely used to simulate dose distributions in ion radiotherapy. The benchmark of the implemented physical models against experimental data plays an important role in improving the accuracy of the simulations. To estimate the accuracy of the inelastic cross sections in SHIELD-HIT, the simulated charge is compared to measured data from a Multi Layer Faraday Cup. In addition, the results are compared to GEANT4, which are already published. Furthermore, energy distributions are simulated with SHIELD-HIT07 and GEANT4.8.1. From a comparison of depth distributions and beam profiles of 100 and 200 MeV protons, we estimate the level of agreement of the two codes. Nuclear interactions predicted by SHIELD-HIT underestimate the total amount of measured charge. The energy distributions from SHIELD-HIT and GEANT4 show differences exceeding the statistical uncertainties of 2%. Due to a difference of the Bragg curve of 0.5 ± 0.3 mm on average, the mean difference in dose is 3.5% with a maximum deviation of 7% for the simulated cases. (note)
Robust Algorithm for Computing Statistical Stark Broadening of Spectral Lines
Iglesias, C A; Sonnad, V
2010-02-10
A method previously developed to solve large-scale linear systems is applied to statistical Stark broadened line shape calculations. The method is formally exact, numerically stable, and allows optimization of the integration over the quasi-static field to assure numerical accuracy. Furthermore, the method does not increase the computational effort and often can decrease it compared to the conventional approach.
Laser spectroscopy of multi-level doppler broadened atomic system
Doppler broadened atomic vapor system can be easily prepared for spectroscopy study than an atomic beam system can be. Vapor cell and hollow cathode discharge lamps are widely used in the experiment. The possibility for observing the trapped state in a Doppler broadened Λ system was examined and confirmed by our early experiment where counter-propagating laser beams are used. For the measurement of the hyperfine structure constants of high-lying levels of heavy elements, we compared the co-propagating and counter-propagating beams in a Doppler broadened ladder systems. It was shown that the counter-propagating beams give a stronger and narrower signal than that from the co-propagating beams. Our treatment also considers the power broadening of the transition. For some photo-ionization experiments, it is necessary to pump two thermally populated levels simultaneously to the higher level and then to the auto-ionizing levels. A technique is proposed to avoid the trapped state and to increase the ionization efficiency.
Quasi-elastic neutron line broadening in nematic liquid crystals
On the basis of a new random walk torsional oscillations model of the amplitude φ0 of rigid flat molecules a quasi-elastic neutron line broadening has been calculated and the results compared to the measurements obtained on the sample of cholesteryl propionate. A good agreement was obtained. (author)
Broadening the concept of international entrepreneurship: 'Consumers as international entrepreneurs'
Y. Chandra; N. Coviello
2010-01-01
We integrate theories from international business, entrepreneurship, innovation, marketing and network economics to develop a four-part typology of ‘consumers as international entrepreneurs’. This broadens the concept of international entrepreneurship and complements the firm-level focus customary i
On-The-Fly neutron Doppler broadening in MCNP
Multi-physics calculations may involve coupling continuous-energy Monte Carlo neutronics codes to CFD codes that provide many thousands or even millions of region temperatures. The traditional Monte Carlo approach - using pre-calculated Doppler broadened nuclear cross-sections - is not feasible for these large multi-physics problems. Instead, an On-the-Fly (OTF) Doppler broadening methodology is required, whereby neutron cross-sections are broadened during the Monte Carlo transport. To this end, we have developed a methodology for MCNP to provide OTF broadening based on cell temperatures during neutron tracking. The method enables the use of many thousands or more temperatures in MCNP Monte Carlo calculations for multi-physics applications, significantly advancing the state-of-the-art by permitting the solution of problems that were not previously possible with continuous-energy Monte Carlo codes. A production library with an extended set of isotopes has been developed for use with MCNP6. Calculations of test problems with MCNP6 and the new library demonstrate the accuracy and effectiveness of the OTF approach. (authors)
Broadening of axial neutron flux difference operating band in Angra I
ANGRA I Technical Specifications requires the axial flux difference to remain within ± 5 percent band, relative to a reference value, for any power level. The reference value is the axial flux difference at a 100% power, all rods (almost) out and equilibrium Xenon distribution. This paper presents the results of several Simulations, performed by FURNAS staff aiming the validation of calculation results against the reload designer's ones. It was also proved that the Axial Flux Difference Operating band can be broadened to ''Ref. +- 6.9% ) without exce eding the limit imposed by the ''envelope-curve''. (author)
Comparison of the Frontier Distributed Database Caching System with NoSQL Databases
CERN. Geneva
2012-01-01
Non-relational "NoSQL" databases such as Cassandra and CouchDB are best known for their ability to scale to large numbers of clients spread over a wide area. The Frontier distributed database caching system, used in production by the Large Hadron Collider CMS and ATLAS detector projects, is based on traditional SQL databases but also has the same high scalability and wide-area distributability for an important subset of applications. This paper compares the architectures, behavior, performance, and maintainability of the two different approaches and identifies the criteria for choosing which approach to prefer over the other.
Final comparison report on ISP-35: Nupec hydrogen mixing and distribution test (Test M-7-1)
This final comparison report summarizes the results of the OECD/CSNI sponsored ISP-35 exercise which was based on NUPEC's Hydrogen Mixing and Distribution Test M-7-1. 12 organizations from 10 different countries took part in the exercise. For the ISP-35 test, a steam/light gas (helium) mixture was released into the lower region of a simplified model of a PWR containment. At the same time, the dome cooling spray was also activated. the transient time histories for gas temperature and concentrations were recorded for each of the 25 compartments of the model containment. The wall temperatures as well as the dome pressure were also recorded. The ISP-35 participants simulated the test conditions and attempted to predict the time histories using their accident analysis codes. Results of these analyses are presented, and comparisons are made between the experimental data and the calculated data. In general, predictions for pressure, helium concentration and gas distribution patterns were achieved with acceptable accuracy
Magnetic Turbulence and Line Broadening in Simulations of Lyman-Alpha Absorption
Gurvich, Alex; Burkhart, Blakesley K.; Bird, Simeon
2016-01-01
We use the Illustris cosmological AREPO simulations to study the effects of gas turbulence and magnetic fields on measurements from the Lyman-Alpha forest. We generate simulated Lyman-Alpha spectra and plot the distributions of Column Density (CDD) and Doppler Width (b) both by adhering to the canonical method of fitting Voigt profiles to absorption lines and by directly measuring the column density and equivalent widths from snapshot data .We investigate the effects of additional unresolved gas turbulence in Illustris by adding an additional broadening term to the line profiles to mimic turbulent broadening. When we do this, we find a measurable effect in the CDD and an offset in the mean of the b distribution corresponding to the additional turbulence. We also compare different MHD runs in AREPO we find that the CDD can measurably differentiate between magnetic seed field at redshifts as low as z=0.1, but we do not find that the b distribution is affected at a detectable level. Our work suggests that the effects of turbulence and magnetic fields from z=2-0.1 can potentially be measured with these diagnostics. This work was supported in part by the NSF REU and DoD ASSURE programs under NSF grant no. 1262851 and by the Smithsonian Institution.
ZHOU Qiuping; CHENG Cheng; MENG Yuedong
2009-01-01
Determination of both the electron density and temperature simultaneously in a cold argon arc-plasma jet by analyzing the Stark broadening of two different emission lines is presented.This method is based on the fact that the Stark broadening of different lines has a different dependence on the electron density and temperature.Therefore,a comparison of two or more line broadenings allows us to diagnose the electron density and temperature simultaneously.In this study we used the first two Balmer series hydrogen lines H_α and H_β for their large broadening width.For this purpose,a small amount of hydrogen was introduced into the discharge gas.The results of the Gigosos-Cardenoso computational model,considering more relevant processes for the hydrogen Balmer lines,is used to process the experimental data.With this method,we obtained reliable electron density and temperature,1.88 ×10 ~(15) cm~(-3 )and 13000 K,respectively.Possible sources of error were also analyzed.
α-Lytic protease, a bacterial serine protease of 198 aminoacids (19800 Da), has been used as a model system for studies of catalytic mechanism, structure-function relationships, and more recently for studies of pro region-assisted protein folding. We have assigned the backbones of the enzyme alone, and of its complex with the tetrahedral transition state mimic N-tert-butyloxycarbonyl-Ala-Pro-boroVal, using double- and triple-resonance 3D NMR spectroscopy on uniformly15N- and 13C/15N-labeled protein.Changes in backbone chemical shifts between the uncomplexed and inhibited form of the protein are correlated with distance from the inhibitor, the displacement of backbone nitrogens, and change in hydrogen bond strength upon inhibitor binding (derived from previously solved crystal structures).A comparison of the solution secondary structure of the uninhibited enzyme with that of the X-ray structure reveals no significant differences.Significant line broadening, indicating intermediate chemical exchange, was observed in many of the active site amides (including three broadened to invisibility), and in a majority of cases the broadening was reversed upon addition of the inhibitor. Implications and possible mechanisms of this line broadening are discussed
Petithuguenin, T.D.P.; Sherman, M.H.
2009-05-01
The purpose of ventilation is to dilute indoor contaminants that an occupant is exposed to. Even when providing the same nominal rate of outdoor air, different ventilation systems may distribute air in different ways, affecting occupants' exposure to household contaminants. Exposure ultimately depends on the home being considered, on source disposition and strength, on occupants' behavior, on the ventilation strategy, and on operation of forced air heating and cooling systems. In any multi-zone environment dilution rates and source strengths may be different in every zone and change in time, resulting in exposure being tied to occupancy patterns.This paper will report on simulations that compare ventilation systems by assessing their impact on exposure by examining common house geometries, contaminant generation profiles, and occupancy scenarios. These simulations take into account the unsteady, occupancy-tied aspect of ventilation such as bathroom and kitchen exhaust fans. As most US homes have central HVAC systems, the simulation results will be used to make appropriate recommendations and adjustments for distribution and mixing to residential ventilation standards such as ASHRAE Standard 62.2.This paper will report on work being done to model multizone airflow systems that are unsteady and elaborate the concept of distribution matrix. It will examine several metrics for evaluating the effect of air distribution on exposure to pollutants, based on previous work by Sherman et al. (2006).
Eidelweijs A Putri
2012-09-01
Full Text Available Pasir Langu village in Cisarua, West Java, is the largest central production area of paprika in Indonesia. On average, for every 200 kilograms of paprika produced, there is rejection amounting to 3 kilograms. This resulted in money loss for wholesalers and wastes. In one year, this amount can be approximately 11.7 million Indonesian rupiahs. Recently, paprika wholesalers in Pasir Langu village recently are developing cold chain management system to maintain quality of paprika so that number of rejection can be reduced. The objective of this study is to compare environmental impacts between conventional and cold chain management system in paprika distribution process using Life Cycle Assessment (LCA methodology and propose Photovoltaic (PV system in paprika distribution process. The result implies that the cold chain system produces more CO2 emission compared to conventional system. However, due to the promotion of PV system, the emission would be reduced. For future research, it is necessary to reduce CO2 emission from transportation process since this process is biggest contributor of CO2 emission at whole distribution process. Keywords: LCA, environmentally friendly distribution, paprika,cold chain, PV system
Mapping species distributions: a comparison of skilled naturalist and lay citizen science recording.
van der Wal, René; Anderson, Helen; Robinson, Annie; Sharma, Nirwan; Mellish, Chris; Roberts, Stuart; Darvill, Ben; Siddharthan, Advaith
2015-11-01
To assess the ability of traditional biological recording schemes and lay citizen science approaches to gather data on species distributions and changes therein, we examined bumblebee records from the UK's national repository (National Biodiversity Network) and from BeeWatch. The two recording approaches revealed similar relative abundances of bumblebee species but different geographical distributions. For the widespread common carder (Bombus pascuorum), traditional recording scheme data were patchy, both spatially and temporally, reflecting active record centre rather than species distribution. Lay citizen science records displayed more extensive geographic coverage, reflecting human population density, thus offering better opportunities to account for recording effort. For the rapidly spreading tree bumblebee (Bombus hypnorum), both recording approaches revealed similar distributions due to a dedicated mapping project which overcame the patchy nature of naturalist records. We recommend, where possible, complementing skilled naturalist recording with lay citizen science programmes to obtain a nation-wide capability, and stress the need for timely uploading of data to the national repository. PMID:26508346
2008-01-01
Granule size distribution of wheat starch is an important characteristic that can affect its chemical composition and functionality. Two types of wheat cultivars, the hard and soft wheat cultivars, grown at Tai'an Experimental Station of Shandong Agricultural University, Taian, Shandong, China, were examined in this study. The granule size distribution and amylose contents in wheat grains were studied and compared, and relationships between the properties were identified. A clear bimodal distribution of granule size was shown in all wheat cultivars. Volume distribution of starch granules shows the typical bimodal with peak values in the ranges of 5.6-6.1 μm and 20.7-24.9 μm, respectively. Also, granule surface area distribution was bimodal with peak values in the ranges of 2.4-3.2 μm and 20.7-24.9 μm, respectively. Number distribution of granules was a typical population with a peak value in the range of 0.54-1.05 μm. Contributions from the granules < 2.8 μm and<9.9 μm to the total volume were in the ranges of 94.2-95.1% and 99.7-99.9% of total number, respectively. Proportions of granules <2.8 μm, 2.8-9.9 μm, 9.9-22.8 μm, and 22.8-42.8 μm were in the ranges of 12.9-14.3%, 28.4-31.1%, 33.5-35.6%, and 19.7-22.7% for hard wheat, and 10.3-13.9%, 26.6-28.1%, 32.7-34.6%, and 24.2-27% for soft wheat. Hard wheat had greater B-type granules (< 9.9 μm), and had fewer granules of 22.8-42.8 μm than soft wheat. Amylose content was positively related to volume percentage of granules 22.8-42.8 μm, and negatively related to volume percentage of granules 2.8-22.8 μm.
Ligny, C.L. de; Remijnse, A.G.
1968-01-01
The mechanism of peak broadening in thin-layer chromatography on cellulose powder was investigated by comparing the peak widths obtained in chromatography with those caused only by diffusion in the cellulose powder, for a set of amino acids of widely differing RF values and six kinds of cellulose po
Broadening and attenuation of UV laser ablation plumes in background gases
Amoruso, S.; Toftmann, B.; Schou, Jørgen
The expansion of a laser-induced silver plume in a background gas has been studied in a variety of gases ranging from helium, oxygen and argon to xenon. We have measured the angular distribution of the total deposit of silver on an array of quartz crystal microbalances as well as the time-of-flight...... distribution with a Langmuir probe. The angular distribution broadens for all gases except for a minor pressure range for the helium background gas, in which a distinct plume narrowing occurs. The behavior of the collected, ablated silver atoms integrated over the full hemisphere is similar for all gases. This...... integral decreases strongly above a characteristic pressure, which depends on the specific gas. The ion time-of-flight signal shows a clear plume splitting into a fast and a slow component except for the ablation plume in a helium gas. (c) 2005 Elsevier B.V. All rights reserved....
Comparison of the Frontier Distributed Database Caching System to NoSQL Databases
One of the main attractions of non-relational “NoSQL” databases is their ability to scale to large numbers of readers, including readers spread over a wide area. The Frontier distributed database caching system, used in production by the Large Hadron Collider CMS and ATLAS detector projects for Conditions data, is based on traditional SQL databases but also adds high scalability and the ability to be distributed over a wide-area for an important subset of applications. This paper compares the major characteristics of the two different approaches and identifies the criteria for choosing which approach to prefer over the other. It also compares in some detail the NoSQL databases used by CMS and ATLAS: MongoDB, CouchDB, HBase, and Cassandra.
Comparison of Probability Distribution Function in Determining Minimum Annual and Monthly Streamflow
Nícolas Reinaldo Finkler
2015-11-01
Full Text Available In this study it was aimed to provide the foundation studies of water availability in the Arroio Belo basin, in Caxias do Sul/RS. Therefore, this study aimed to analyze the application of Weibull, Normal, LogNormal, Gumbel (minimum, LogPearson and Pearson theoretical probability functions to data of minimum streamflows for seven consecutive days of the basin. The analysis had two approaches: application in annual data, and then on monthly data, considering seasonality. To verify the adherence to the estimated probabilities of observed frequencies, we applied three tests: Kolmogorov-Smirnov, Anderson-Darling and Chi-Squared. The results show that the Log-Pearson III distribution shows greater accuracy in representing the annual data of the series and reach the best fit of the minimum streamflow. The monthly data analysis indicated the use of the distribution Pearson III, which showed higher suitability to the minimum streamflow data.
Comparison of the pressure distribution of a wind turbine blade based on field experiment and CFD
Field experiment and numerical simulation are performed on a 33 kW horizontal axis wind turbine. The distribution of pressure is gathered by disposed 191 taped pressure sensors span-ward on seven particular sections of a blade. And the parameters of experimental condition of inflow and operation condition of the wind turbine are obtained at the same time. And then, the three-dimensional Reynolds averaged incompressible Navier-Stokes equations and the RNG κ-ε turbulence model are used to study the aerodynamic characteristics of the wind turbine. The numerical method is proved to be more effective by contrasting the numerical results to the field experimental data. For the calculation results of the blade pressure, the closer to the root of the blade the more consistent to the values of the experiment. A greater differential is shown at the leading edge than the trailing edge. The pressure distribution contours of the blade surface are obtained too
Tian, Kai; Cao, Zhou; Xue, Yu-Xiong; Yang, Shi-Yu
2010-01-01
Heavy ions and pulsed lasers are important means to simulate the ionization damage effects on semiconductor materials. The analytic solution of high-energy heavy ion energy loss in silicon has been obtained using the Bethe-Bloch formula and the Kobetich-Katz theory, and some ionization damage parameters of Fe ions in silicon, such as the track structure and ionized charge density distribution, have been calculated and analyzed according to the theoretical calculation results. Using the Gaussian function and Beer's law, the parameters of the track structure and charge density distribution induced by a pulsed laser in silicon have also been calculated and compared with those of Fe ions in silicon, which provides a theoretical basis for ionization damage effect modeling.
Comparison of Particle Number Size Distributions in Three Central European Capital Cities
Zíková, Naděžda; Borsós, T.; Řimnáčová, Daniela; Smolík, Jiří; Wagner, Zdeněk; Weidinger, T.; Burkart, J.; Steiner, G.; Reischl, G.; Hitzenberger, R.; Schwarz, Jaroslav; Salma, I.; Ždímal, Vladimír
Prague : Czech Aerosol Society, 2013, A212. ISBN N. [European Aerosol Conference (EAC 2013). Prague (CZ), 01.09.2013-06.09.2013] R&D Projects: GA ČR GAP209/11/1342 Grant ostatní: HSRF(HU) K84091; WFW(AT) P19515-N20 Institutional support: RVO:67985858 Keywords : urban environment * diurnal variation * number size distribution Subject RIV: CF - Physical ; Theoretical Chemistry http://eac2013.cz/index.php
BÜTTNER, M.; Schiffler, M.; Weber, P; Seidel, P.
2011-01-01
In this work we compare previously measured energy barriers over the course of temperature with the results of simulations of the behaviour of the energy barriers. For the measurements the temperature dependent magnetorelaxation method (TMRX) was used. For the simulations of the energy barrier distribution we have used the real particles properties such as anisotropy and core size volume of the fractions of two magnetically fractionated ferrofluids. There is a good agreement between the simul...
A comparison between different methods for determining grain distribution in coarse channel beds
Alessio Cislaghi; Enrico Antonio Chiaradia; Gian Battista Bischetti
2016-01-01
The determination of grain size distribution in alluvial channels plays a crucial role in understanding fluvial dynamics and processes (e.g., hydraulic resistance, sediment transport and erosion, and habitat suitability). However, to determine an accurate distribution, tremendous field efforts are often required. Traditionally, the grain size distribution of channel beds have been obtained by manually counting a set of randomly selected stones (the“pebble count”). Based on this elementary principle, many authors have proposed different adaptations to overcome weaknesses and problems with the original method; with the development of digital technology, photographic methods have been developed in order to sig-nificantly reduce the time spent in the field. Two of these“image-assisted”methods include Automated Grain Sizing, AGS, and Manual Photo Sieving, MPS. In this study, AGS and MPS were applied under ideal laboratory conditions, to be used as reference, and in two field conditions with different degrees of difficulty in terms of visual determination of the grain size distribution; these included an artificial unlined channel and two natural mountainous streams. The results were compared with those obtained with the pebble-count method. In general, strong agreement between the methods was found when they were applied under favorable conditions (”the laboratory”), and the differences between the image-assisted and pebble count methods were similar to those found in previous studies. Despite being more time consuming, MPS was deemed preferable to AGS when conditions are not optimal;in these cases, the time spent on image elaboration significantly increased in the AGS method (approximately three-fold), but the estimation error of the median grain size decreased by approximately 37%. The use of image-assisted analysis has proven to be robust for characterizing sediment in watercourse beds and reducing fieldwork time, but because field conditions can
Ardani, K.; Davidson, C.; Margolis, R.; Nobler, E.
2015-01-01
This report presents results from an analysis of distributed photovoltaic (PV) interconnection and deployment processes in the United States. Using data from more than 30,000 residential (up to 10 kilowatts) and small commercial (10-50 kilowatts) PV systems, installed from 2012 to 2014, we assess the range in project completion timelines nationally (across 87 utilities in 16 states) and in five states with active solar markets (Arizona, California, New Jersey, New York, and Colorado).
Comparison of algorithms for distributed space exploration in a simulated environment
Cikač, Jaka
2014-01-01
Space exploration algorithms aim to discover as much unknown space as possible as efficiently as possible in the shortest possible time. To achieve this goal, we use distributed algorithms, implemented on multi-agent systems. In this work, we explore, which of the algorithms can efficiently explore space in a simulated environment Gridland. Since Gridland, in it's original release, was not meant for simulating space exploration, we had to make some modifications and enable movement history an...
Xudong Zhao; Zhilong Chen; Huadong Gong
2015-01-01
Water distribution network (WDN) is critical to the city service, economic rehabilitation, public health, and safety. Reconstructing the WDN to improve its resilience in seismic disaster is an important and ongoing issue. Although a considerable body of research has examined the effects of different reconstruction strategies on seismic resistance, it is still hard for decision-makers to choose optimal resilience enhancing strategy. Taking the pipeline ductile retrofitting and network meshed e...
Bhattacharjee, M. C.; Abouammoh, A. M. [ابو عمه; Ahmed, A. N.; Barry, A. M.
2000-01-01
We investigate some preservation properties of two nonparametric classes of survival distributions and their duals, under appropriate reliability operations. The aging properties defining these nonparametric classes are based on comparing the mean life of a new unit to the mean residual life function of the asymptotic remaining survival time of the unit under repeated perfect repairs. They are motivated from a point of view that realistic notions of degradation, applicable t...
Comparison of dose distribution between hypofractionated IMRT and SRT plans in lung tumor
Objective: To compare the characteristics of dose distribution between hypofractionated intensity modulated radiotherapy (IMRT) and hypofractionated stereotactic radiotherapy (SRT) plans in lung tumor and to select an optimal clinical approach. Methods: SRT plans were designed for 16 patients with lung tumors who had received IMRT between April 2007 and April 2008. The dose distribution of target volume and normal tissues, conformal index (CI) and heterogenous index (HI) were analyzed using the dose-volume histogram (DVH) for the IMRT and SRT plans. Results: The mean dose and equivalent uni-form dose of planning target volume (PTV) in IMRT were similar to those in SRT. SRT had significantly better CI and HI than IMRT (t = 2.77, P 0.05). The lung V20 of IMRT and SRT was 6.9% ± 2.1% and 4.2%± 1.9%, respectively (t = 3.30, P 3 or the long diameter of tumor is less than 4.7 cm, hypofractionated SRT has similar dose distribution to hypofractionated IMRT, while the lung dose was lower in the former. (authors)
Barkana, R
2002-01-01
Recently, Lanzetta et al. (2002) have measured the distribution of star formation rate intensity in galaxies at various redshifts. This data set has a number of advantages relative to galaxy luminosity functions; the effect of surface-brightness dimming on the selection function is simpler to understand, and this data set also probes the size distribution of galactic disks. We predict this function using semi-analytic models of hierarchical galaxy formation in a LCDM cosmology. We show that the basic trends found in the data follow naturally from the redshift evolution of dark matter halos. The data are consistent with a constant efficiency of turning gas into stars in galaxies, with a best-fit value of 2.3[+0.8][-0.5]% (2-sigma), where dust obscuration is neglected; equivalently, the data are consistent with a cosmic star formation rate which is constant to within a factor of two at all redshifts above two. However, the practical ability to use this kind of distribution to measure the total cosmic star forma...
M E ZOMORRODIAN; M HASHEMINIA; S M ZABIHINPOUR; A MIRJALILI
2016-08-01
Inclusive momentum distributions of charged particles are measured in dijet events. Events were produced at the AMY detector with a centre of mass energy of 60 ${\\rm GeV}$. Our results were compared, on the one hand to those obtained from other $e^+ e^-$, $ep$ as well as CDF data, and on the other hand to the perturbative QCD calculations carried out in the framework of the modified leading log approximation (MLLA) and assuming local parton--hadron duality (LPHD). A fit of the shape of the distributions yields $\\scr Q_{eff} = 263 \\pm 13 {\\rm MeV}$ for the AMY data. In addition, a fit to the evolution of the peak position with dijet mass using all data from different experiments gives $\\scr Q_{eff} = 226 \\pm 18 {\\rm MeV}$. Next, αs was extracted using the shape of the distribution at the Z0 scale, with a value of 0.118 \\pm 0.013. This is consistent, within the statistical errors, with many accurate measurements. We conclude that it is the success of LPHD + MLLA that the extracted value of $\\alpha_{s}$ is correct. Possible explanations for all these features will be presented in this paper.
Comparison of dose distributions for various applicators for treatment of rectal cancer
In this report, we compare various methods of rectal cancer treatment using different implants for different target configurations. We represented the target as a sector of a circle with an angle of 120o, and each case has a different thickness of 5,10,15 and 20 mm. The tumor has a length of 5 cm. The tumor configuration is shown. We calculated 16 treatment plans for various tumors using 4 different applicators for the MicroSelectron: 1. Simple proctostat with central channel. The applicator can be completed with various shields: 90, 180 and 270 degree. 2. MUPIT applicator set. 3. Miami Applicator Set. 4. Interstitial implant. Needles were separated as in the Paris dosimetry system. Comparison was performed with the following parameters: Coverage index (CI), External volume index (EI), Relative Dose Homogeneity index (HI), Overdose volume index (OI)
Comparison of measured and simulated fast ion velocity distributions in the TEXTOR tokamak
Here we demonstrate a comprehensive comparison of collective Thomson scattering (CTS) measurements with steady-state Monte Carlo simulations performed with the ASCOT and VENUS codes. The measurements were taken at a location on the magnetic axis as well as at an off-axis location, using two projection directions at each location. The simulations agree with the measurements on-axis, but for the off-axis geometries discrepancies are observed for both projection directions. For the near perpendicular projection direction with respect to the magnetic field, the discrepancies between measurement and simulations can be explained by uncertainty in plasma parameters. However, the discrepancies between measurement and simulations for the more parallel projection direction cannot be explained solely by uncertainties in plasma parameters. Here anomalous fast ion transport is a possible explanation for the discrepancy.
Comparison of measured and simulated fast ion velocity distributions in the TEXTOR tokamak
Moseev, D; Meo, F; Korsholm, S B; Bindslev, H; Furtula, V; Leipold, F; Michelsen, P K; Nielsen, S K; Salewski, M; Stejner, M [Association Euratom - Risoe National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark); Koskela, T; Asunta, O [Aalto University, EURATOM-TEKES, PO Box 15100 FI-00076 AALTO (Finland); Albergante, M [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, CH-1015 Lausanne (Switzerland); Buerger, A; Kantor, M Yu; Schmitz, O [FZ Juelich GmbH, EURATOM, Trilateral Euregio Cluster, D-52425 Juelich (Germany); Westerhof, E, E-mail: dmmo@risoe.dtu.dk [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, Nieuwegein (Netherlands)
2011-10-15
Here we demonstrate a comprehensive comparison of collective Thomson scattering (CTS) measurements with steady-state Monte Carlo simulations performed with the ASCOT and VENUS codes. The measurements were taken at a location on the magnetic axis as well as at an off-axis location, using two projection directions at each location. The simulations agree with the measurements on-axis, but for the off-axis geometries discrepancies are observed for both projection directions. For the near perpendicular projection direction with respect to the magnetic field, the discrepancies between measurement and simulations can be explained by uncertainty in plasma parameters. However, the discrepancies between measurement and simulations for the more parallel projection direction cannot be explained solely by uncertainties in plasma parameters. Here anomalous fast ion transport is a possible explanation for the discrepancy.
XPS of guanidinium ionic liquids: a comparison of charge distribution in nitrogenous cations.
Santos, Ana R; Blundell, Rebecca K; Licence, Peter
2015-05-01
Herein, we investigate the first X-ray photoelectron spectroscopy (XPS) data for a range of functionalised guanidinium based systems that are commonly employed in the dissolution of biomolecules. We define a peak fitting model which allows the direct comparison to more common cation sets including dialkyl-imidazolium, pyrrolidinium, and quaternary ammonium based systems. The measured binding energies (BEs) of the N 1s and C 1s components are presented and notable variations discussed. These data show a large difference between measured binding energies for the Ncation 1s when compared to other families of ionic liquids. These results suggest a weaker anion/cation interaction thus the anion is more able to interact with a solid matrix, i.e. keratin, silk, chitin, collagen, cellulose, and become more active in dissolution. PMID:25868478
Bai, Lina; Xie, Ting; Hu, Qingqing; Deng, Changyan; Zheng, Rong; Chen, Wanping
2015-10-01
Ferritins are highly conserved proteins that are widely distributed in various species from archaea to humans. The ubiquitous characteristic of these proteins reflects the pivotal contribution of ferritins to the safe storage and timely delivery of iron to achieve iron homeostasis. This study investigated the ferritin genes in 248 genomes from various species, including viruses, archaea, bacteria, and eukarya. The distribution comparison suggests that mammals and eudicots possess abundant ferritin genes, whereas fungi contain very few ferritin genes. Archaea and bacteria show considerable numbers of ferritin genes. Generally, prokaryotes possess three types of ferritin (the typical ferritin, bacterioferritin, and DNA-binding protein from starved cell), whereas eukaryotes have various subunit types of ferritin, thereby indicating the individuation of the ferritin family during evolution. The characteristic motif analysis of ferritins suggested that all key residues specifying the unique structural motifs of ferritin are highly conserved across three domains of life. Meanwhile, the characteristic motifs were also distinguishable between ferritin groups, especially phytoferritins, which show a plant-specific motif. The phylogenetic analyses show that ferritins within the same subfamily or subunits are generally clustered together. The phylogenetic relationships among ferritin members suggest that both gene duplication and horizontal transfer contribute to the wide variety of ferritins, and their possible evolutionary scenario was also proposed. The results contribute to a better understanding of the distribution, characteristic motif, and evolutionary relationship of the ferritin family.
The comparison of calculated and experimental microdosimetric distributions for carbon ions
Palajová, Zdenka; Spurný, František; Davídková, Marie
2007-01-01
Roč. 122, 1-4 (2007), s. 491-493. ISSN 0144-8420. [Symposium on Microdosimetry /14./. Venezia, 13.11.2005-18.11.2005] R&D Projects: GA ČR GA202/04/0795; GA ČR(CZ) GD202/05/H031 Institutional research plan: CEZ:AV0Z10480505 Keywords : microdosimetry distributions * carbon ions * theoretical calculation Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.528, year: 2007
Arpanaei, Ayyoob; Heebøll-Nielsen, Anders; Hubbuch, Jürgen; Thomas, Owen R. T.; Hobley, Timothy John
The hydrodynamic properties of an expanded bed contactor with 30 cm or 150 cm internal diameter, which employs a rotating or oscillating fluid distributor, were compared to prototype columns of 60 cm or 150 cm diameter employing local stirring (fixed wall nozzles plus central bottom mounted stirrer......) for fluid distribution. Fluid introduction through a rotating fluid distributor was found to give superior hydrodynamic characteristics in the 30 cm and 150 cm diameter column compared to using the local stirrer in both the 60 cm and 150 cm diameter columns. The shortcomings of the local stirring...
Van Roosmalen, Lieke Petronella G; Sonnenborg, Torben; Jensen, Karsten Høgh; Christensen, Jens Hesselbjerg
2011-01-01
HIRHAM4 regional climate model (RCM). The aim of this study was to determine whether the choice of bias-correction method, applied to the RCM data, aff ected the projected hydrological changes. One method consisted of perturbation of observed data (POD) using climate change signals derived from the RCM...... output, while the other consisted of distribution-based scaling (DBS) of the RCM output. Distributionbased scaling resulted in RCM control period data closely approaching the observed climate data and thereby considerably improved the simulation of recharge and stream discharges. When comparing the...
Andresen, Markus; Ma, Ke; Liserre, Marco; Blaabjerg, Frede
A Smart Transformer (ST) can cover an important managing role in the future electrical distribution grid. For the moment, the reliability and cost are not competitive with traditional transformers and create a barrier for its application. This work conduct detail designs and analysis for a...... promising modular ST solution, which is composed of Modular Multi-level converter, Quad Active Bridge DC-DC converters, and two-level voltage source converters. The focus is put on the loading conditions and thermal stress of power semiconductor devices in order to discover critical parts of the whole...
Masuda, Hiroko; Keith A. Baggerly; Ying WANG; Iwamoto, Takayuki; Brewer, Takae; Pusztai, Lajos; Kai, Kazuharu; Kogawa, Takahiro; Finetti, Pascal; Birnbaum, Daniel; Dirix, Luc; Wendy A Woodward; Reuben, James M.; Krishnamurthy, Savitri; Symmans, W Fraser
2013-01-01
Introduction Because of its high rate of metastasis, inflammatory breast cancer (IBC) has a poor prognosis compared with non-inflammatory types of breast cancer (non-IBC). In a recent study, Lehmann and colleagues identified seven subtypes of triple-negative breast cancer (TNBC). We hypothesized that the distribution of TNBC subtypes differs between TN-IBC and TN-non-IBC. We determined the subtypes and compared clinical outcomes by subtype in TN-IBC and TN-non-IBC patients. Methods We determi...
Tracer experiments were carried out to compare the plant uptake behavior of Tc and Re from nutrient solutions. Radish plants, transplanted to nutrient solution including various tracers, showed the same uptake and distribution of 95mTc and 183Re. The trend was the same when the 99Tc and stable-Re concentrations were increased in nutrient solution. The behavior of other elements was different from that of Tc and Re. These findings suggest the possible use of Re as the chemical analogue of Tc in soil solution to plant uptake experiments
A comparison of cost-based pricing rules for natural gas distribution utilities
Partial-equilibrium social welfare deadweight losses under uniform Ramsey pricing, a cost allocation pricing method, and the actual average revenues by customer class for two natural gas distribution utilities are calculated and compared. Marginal cost estimates are derived from a multiple-output translog variable cost function and used, along with three sets of demand elasticities, to generate the Ramsey prices and welfare losses. The actual and cost-allocation prices are taken directly from rate case files. The largest social welfare losses are associated with the cost-allocation rule, as high as 10-25% of revenue, despite suggestions in the literature to the contrary. (Author)
Sanders, Paul G; Xu, Ning; Dalka, Tom M; Maricq, M Matti
2003-09-15
Particle size distributions of light-duty vehicle brake wear debris are reported with careful attention paid to avoid sampling biases. Electrical low-pressure impactor and micro-orifice uniform deposit impactor measurements yield consistent size distributions, and the net particulate matter mass from each method is in good agreement with gravimetric filter measurements. The mass mean diameter of wear debris from braking events representative of urban driving is 6 microm, and the number-weighted mean is 1-2 microm for three currently used classes of lining materials: low metallic, semimetallic, and non-asbestos organic (NAO). In contrast, the wear rates are very material dependent, both in number and mass of particles, with 3-4 times higher emissions observed from the low metallic linings as compared to the semimetallic and NAO linings. Wind tunnel and test track measurements demonstrate the appearance of micron size particles that correlate with braking events, with approximately 50% of the wear debris being airborne for the test vehicle in this study. Elemental analysis of the wear debris reveals a consistent presence of the elements Fe, Cu, and Ba in both dynamometer and test track samples. PMID:14524436
G Subashini; M C Bhuvaneswari
2012-12-01
Parallel and distributed systems play an important part in the improvement of high performance computing. In these type of systems task scheduling is a key issue in achieving high performance of the system. In general, task scheduling problems have been shown to be NP-hard. As deterministic techniques consume much time in solving the problem, several heuristic methods are attempted in obtaining optimal solutions. This paper presents an application of Elitist Non-dominated Sorting Genetic Algorithm (NSGA-II) and a Non-dominated Sorting Particle Swarm Optimization Algorithm (NSPSO) to schedule independent tasks in a distributed system comprising of heterogeneous processors. The problem is formulated as a multi-objective optimization problem, aiming to obtain schedules achieving minimum makespan and ﬂowtime. The applied algorithms generate Pareto set of global optimal solutions for the considered multi-objective scheduling problem. The algorithms are validated against a set of benchmark instances and the performance of the algorithms evaluated using standard metrics. Experimental results and performance measures infer that NSGA-II produces quality schedules compared to NSPSO.
Borges, Pablo de Amorim; Franke, Johannes; da Anunciação, Yumiko Marina Tanaka; Weiss, Holger; Bernhofer, Christian
2016-01-01
Available climatological information of Distrito Federal does not satisfy the requirements for detailed climate diagnosis, as they do not provide the necessary spatial resolution for water resources management purposes. Annual and seasonal climatology (1971-2000) of precipitation from 6 meteorological stations and 54 rain gauges from Central Brazil were used to test eight different spatial interpolation methods. Geographical factors (i.e., altitude, longitude and latitude) explain a large portion of precipitation in the region, and therefore, multivariate models were included. The performance of estimations was assessed through independent validation using mean square error, correlation coefficient and Nash-Sutcliffe efficiency criterion. Inverse distance weighting (IDW), ordinary kriging (OK) and the multivariate regression with interpolation of residuals by IDW (MRegIDW) and OK (MRegOK) have performed the lowest errors and the highest correlation and Nash-Sutcliffe efficiency criterion. In general, interpolation methods provide similar spatial distributions of rainfall wherever observation network is dense. However, the inclusion of geographical variables to the interpolation method should improve estimates in areas where the observation network density is low. Nevertheless, the assessment of uncertainties using a geostatistical method provides supplementary and qualitative information which should be considered when interpreting the spatial distribution of rainfall.
Comparison of protocols for measuring cosmetic ingredient distribution in human and pig skin.
Gerstel, D; Jacques-Jamin, C; Schepky, A; Cubberley, R; Eilstein, J; Grégoire, S; Hewitt, N; Klaric, M; Rothe, H; Duplan, H
2016-08-01
The Cosmetics Europe Skin Bioavailability and Metabolism Task Force aims to improve the measurement and prediction of the bioavailability of topically-exposed compounds for risk assessment. Key parameters of the experimental design of the skin penetration studies were compared. Penetration studies with frozen human and pig skin were conducted in two laboratories, according to the SCCS and OECD 428 guidelines. The disposition in skin was measured 24h after finite topical doses of caffeine, resorcinol and 7-ethoxycoumarin. The bioavailability distribution in skin layers of cold and radiolabelled chemicals were comparable. Furthermore, the distribution of each chemical was comparable in human and pig skin. The protocol was reproducible across the two laboratories. There were small differences in the amount of chemical detected in the skin layers, which were attributed to differences in washing procedures and anatomical sites of the skin used. In conclusion, these studies support the use of pig skin as an alternative source of skin should the availability of human skin become a limiting factor. If radiolabelled chemicals are not available, cold chemicals can be used, provided that the influence of chemical stability, reactivity or metabolism on the experimental design and the relevance of the data obtained is considered. PMID:27039122
Comparison of Magnetic Flux Distribution between a Coronal Hole and a Quiet Region
Zhang, Jun; Wang, Haimin
2006-01-01
Employing Big Bear Solar Observatory (BBSO) deep magnetograms and H${\\alpha}$ images in a quiet region and a coronal hole, observed on September 14 and 16, 2004, respectively, we have explored the magnetic flux emergence, disappearance and distribution in the two regions. The following results are obtained: (1) The evolution of magnetic flux in the quiet region is much faster than that in the coronal hole, as the flux appeared in the form of ephemeral regions in the quiet region is 4.3 times as large as that in the coronal hole, and the flux disappeared in the form of flux cancellation, 2.9 times as fast as in the coronal hole. (2) More magnetic elements with opposite polarities in the quiet region are connected by arch filaments, estimating from magnetograms and H${\\alpha}$ images. (3) We measured the magnetic flux of about 1000 magnetic elements in each observing region. The flux distribution of network and intranetwork (IN) elements is similar in both polarities in the quiet region. For network fields in t...
Comparison of the Porter-Thomas distribution with neutron resonance data of even-even nuclei
The low-energy neutron resonance data of the even-even nuclei 152Sm, 158Gd, 162Dy, 166,168Er, 182W, 232Th, and 236,238U have been examined in order to test the validity of the Porter-Thomas distribution of the reduced neutron widths---a chi-squared distribution with one degree of freedom (v=1). In an attempt to circumvent the ever-present problems of missed or spurious s wave levels as well as extra p wave levels, a maximum likelihood statistic was employed which used only measured widths greater than some minimum value. A Bayes-theory test applied to the data helped to ensure that p wave contamination of the s wave level population was not significant. The error-weighted value of the number of degrees of freedom for the nine nuclei studied, left-angle v right-angle=0.98±0.10, is consistent with the theoretical expectation of v=1
Comparison of the quantities and subset distributions of natural killer cells among different races
FENG Yan-meng; ZHANG Rui-jun; ZHU Hong; PENG Hong; ZHOU Xiao-ping; HONG Kun-xue; LIU Jian-li; CHEN Jian-ping; SHAO Yi-ming
2010-01-01
Background Natural killer (NK) cells play critical roles in host immune defense, while the quantities and subset distributions may vary among different races. To address the difference, we compared these variables among Chinese Han, the Caucasians and the Blacks. The study may provide critical background information for both basic research and clinical investigation.Methods Blood samples collected from populations of different races were tested within 12 hours after collection and subsets of NK cells were characterized using flow cytometry.Results The absolute NK count in the Chinese Han was significantly higher than that in the Caucasian. The Han and Caucasian groups showed higher percentages of cytotoxic subset compared to that of the Black group. The percentage of cytokine-producing subset of Chinese Han group was lower than that of Caucasian and Black groups. Black group had a higher percentage of function-unknown NK subset than that of the Hah and Caucasian groups.Conclusion Our data indicated that NK cell count and the distribution of different subsets varied among different races,which should be taken into consideration in related investigations.
F. Cairo
2010-09-01
Full Text Available An FSSP-100 Optical Particle Counter designed to count and size particles in the micron range and a backscattersonde that measures in-situ particle optical properties such as backscatter and depolarization ratio, are part of the payload of the high altitude research aircraft M55 Geophysica. This aircraft was deployed in tropical field campaigns in Bauru, Brasil (TROCCINOX, 2004 Darwin, Australia (SCOUT-Darwin, 2005 and Ouagadougou, Burkina Faso (SCOUT-AMMA, 2006. In those occasions, measurements of particle size distributions and optical properties within cirrus cloud were performed. Scope of the present work is to assess and discuss the consistency between the particle volume backscatter coefficient observed by the backscattersonde and the same parameter retrieved by optical scattering theory applied to particle size distributions as measured by the FSSP-100. In addition, empirical relationships linking the optical properties measured in-situ by the backscattersonde, which generally can be obtained by remote sensing techniques (LIDAR, and microphysical bulk properties like total particle number, surface and volume density will be presented and discussed.
Spectrally selective optical pumping in Doppler-broadened cesium atoms
The D1 line spectrally selective pumping process in Doppler-broadened cesium is analyzed by solving the optical Bloch equations. The process, described by a three-level model with the Λ scheme, shows that the saturation intensity of broadened atoms is three orders of magnitude larger than that of resting atoms. The |Fg = 3> → |Fe = 4> resonance pumping can result in the ground state |Fg = 4, mF = 4> sublevel having a maximum population of 0.157 and the population difference would be about 0.01 in two adjacent magnetic sublevels of the hyperfine (HF) state Fg = 4. To enhance the anisotropy in the ground state, we suggest employing dichromatic optical HF pumping by adding a laser to excite D1 line |Fg = 4> → |Fe = 3> transition, in which the cesium magnetometer sensitivity increases by half a magnitude and is unaffected by the nonlinear Zeeman effect even in Earth's average magnetic field. (atomic and molecular physics)
Pulsed Spin Locking in Spin-1 NQR: Broadening Mechanisms
Malone, Michael W.
Nuclear Quadrupole Resonance (NQR) is a branch of magnetic resonance physics that allows for the detection of spin I > 1/2 nuclei in crystalline and semi-crystalline materials. Through the application of a resonant radio frequency (rf) pulse, the nuclei's response is to create an oscillating magnetic moment at a frequency unique to the target substance. This creates the NQR signal, which is typically weak and rapidly decaying. The decay is due to the various line broadening mechanisms, the relative strengths of which are functions of the specific material, in addition to thermal relaxation processes. Through the application of a series of rf pulses the broadening mechanisms can be refocused, narrowing the linewidth and extending the signal in time. Three line broadening mechanisms are investigated to explain the NQR signal's linewidth and behavior. The first, electric field gradient (EFG) inhomogeneity, is due to variations in the local electric environment among the target nuclei, for instance from crystal imperfections. While EFG inhomogeneity can vary between samples of the same chemical composition and structure, the other broadening mechanisms of homonuclear and heteronuclear dipolar coupling are specific to this composition and structure. Simple analytical models are developed that explain the NQR signal response to pulse sequences by accounting for the behavior of each broadening mechanism. After a general theoretical introduction, a model of pairs of spin-1 nuclei is investigated, and the refocusing behaviors of EFG and homonuclear dipolar coupling are analyzed. This reveals the conditions where EFG is refocused but homonuclear dipolar coupling is not. In this case the resulting signal shows a rapid decay, the rate of which becomes a measure of interatomic distances. This occurs even in the more complex case of a powder sample with its many randomly oriented crystallites, under particular pulsing conditions. Many target NQR compounds are rich in hydrogen
Positive emotions and the social broadening effects of Barack Obama.
Ong, Anthony D; Burrow, Anthony L; Fuller-Rowell, Thomas E
2012-10-01
Past experiments have demonstrated that the cognitive broadening produced by positive emotions may extend to social contexts. Building on this evidence, we hypothesized that positive emotions triggered by thinking about Barack Obama may broaden and expand people's sense of self to include others. Results from an expressive-writing study demonstrated that African American college students prompted to write about Obama immediately prior to and after the 2008 presidential election used more plural self-references, fewer other-references, and more social references. Mediation analyses revealed that writing about Obama increased positive emotions, which in turn increased the likelihood that people thought in terms of more-inclusive superordinate categories (we and us rather than they and them). Implications of these findings for the role of positive emotions in perspective-taking and intergroup relations are considered. PMID:22905966