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Sample records for characteristic length scale

  1. Characteristic Length Scale of Electric Transport Properties of Genomes

    CERN Document Server

    Shih, C T

    2005-01-01

    A tight-binding model together with a novel statistical method are used to investigate the relation between the sequence-dependent electric transport properties and the sequences of protein-coding regions of complete genomes. A correlation parameter $\\Omega$ is defined to analyze the relation. For some particular propagation length $w_{max}$, the transport behaviors of the coding and non-coding sequences are very different and the correlation reaches its maximal value $\\Omega_{max}$. $w_{max}$ and \\omax are characteristic values for each species. The possible reason of the difference between the features of transport properties in the coding and non-coding regions is the mechanism of DNA damage repair processes together with the natural selection.

  2. A Characteristic Particle Length

    CERN Document Server

    Roberts, Mark D

    2015-01-01

    It is argued that there are characteristic intervals associated with any particle that can be derived without reference to the speed of light $c$. Such intervals are inferred from zeros of wavefunctions which are solutions to the Schr\\"odinger equation. The characteristic length is $\\ell=\\beta^2\\hbar^2/(8Gm^3)$, where $\\beta=3.8\\dots$; this length might lead to observational effects on objects the size of a virus.

  3. Characteristics of thick disks formed through minor mergers: stellar excesses and scale lengths

    Science.gov (United States)

    Qu, Y.; Di Matteo, P.; Lehnert, M. D.; van Driel, W.

    2011-06-01

    By means of a series of N-body/SPH simulations we investigate the morphological properties of thick stellar disks formed through minor mergers with, e.g. a range of gas-to-stellar mass ratios. We show that the vertical surface density profile of the post-merger thick disk follows a sech function and has an excess in the regions furthest away from the disk mid-plane (z ≳ 2 kpc). This stellar excess also follows a sech function with a larger scale height than the main thick disk component (except at large radii). It is usually dominated by stars from the primary galaxy, but this depends on the orbital configuration. Stars in the excess have a rotational velocity lower than that of stars in the thick disk, and they may thus be confused with stars in the inner galactic halo, which can have a similar lag. Confirming previous results, the thick disk scale height increases with radius and the rate of its increase is smaller for more gas rich primary galaxies. On the contrary, the scale height of the stellar excess is independent of both radius and gas fraction. We also find that the post-merger thick disk has a radial scale length which is 10-50% larger than that of the thin disk. Two consecutive mergers have basically the same effect on heating the stellar disk as a single merger of the same total mass, i.e., the disk heating effect of a few consecutive mergers does not saturate but is cumulative. To investigate how thick disks produced through secular processes may differ from those produced by minor mergers, we also simulated gravitationally unstable gas-rich disks ("clumpy disks"). These clumpy disks do not produce either a stellar excess or a ratio of thick to thin disk scale lengths greater than one. Comparing our simulation results with observations of the Milky Way and nearby galaxies shows that our results for minor mergers are consistent with observations of the ratio of thick to thin disk scale lengths and with the "Toomre diagram" (the sum in quadrature of

  4. Characteristics of thick disks formed through minor mergers: stellar excesses and scale lengths

    CERN Document Server

    Qu, Yan; Lehnert, Matthew D; van Driel, Wim

    2011-01-01

    By means of N-body/SPH simulations we investigate the morphological properties of thick disks formed through minor mergers. We show that the vertical surface density profile of the post-merger thick disk follows a sech function and has an excess in the regions far from the disk mid-plane (z>2kpc). This stellar excess also follows a sech function with a larger scale height than the main thick disk component, and it is usually dominated by stars from the primary galaxy. Stars in the excess have a rotational velocity lower than that of stars in the thick disk, and they may thus be confused with stars in the inner galactic halo. The thick disk scale height increases with radius and the rate of its increase is smaller for more gas rich primary galaxies. On the contrary, the scale height of the stellar excess is independent of both radius and gas fraction. We also find that the post-merger thick disk has a radial scale length which is 10-50% larger than that of the thin disk. Two consecutive mergers have basically ...

  5. Effects of Characteristic Length Scales on the Exciton Dynamics in Rubrene Single Crystals

    OpenAIRE

    Gieseking, Björn; Schmeiler, Teresa; Müller, Benjamin; Deibel, Carsten; Engels, Bernd; Dyakonov, Vladimir; Pflaum, Jens

    2013-01-01

    As for its inorganic counterparts the future developments in organic electronics are driven by an advanced device miniaturization. Therefore, the opto-electronic behavior of up-to-date devices is progressively governed by the local structural environment. However, there is a lack of organic semiconductor materials providing access to the fundamental structure-functionality relation, either due to limitations by their inherent growth or their optical characteristics. In this work we present a ...

  6. Characteristic length scales and time-averaged transport velocities of suspended sediment in the mid-Atlantic Region, USA

    Science.gov (United States)

    Pizzuto, James; Schenk, Edward R.; Hupp, Cliff R.; Gellis, Allen; Noe, Greg; Williamson, Elyse; Karwan, Diana L.; O'Neal, Michael; Marquard, Julia; Aalto, Rolf; Newbold, Denis

    2014-02-01

    Watershed Best Management Practices (BMPs) are often designed to reduce loading from particle-borne contaminants, but the temporal lag between BMP implementation and improvement in receiving water quality is difficult to assess because particles are only moved downstream episodically, resting for long periods in storage between transport events. A theory is developed that describes the downstream movement of suspended sediment particles accounting for the time particles spend in storage given sediment budget data (by grain size fraction) and information on particle transit times through storage reservoirs. The theory is used to define a suspended sediment transport length scale that describes how far particles are carried during transport events, and to estimate a downstream particle velocity that includes time spent in storage. At 5 upland watersheds of the mid-Atlantic region, transport length scales for silt-clay range from 4 to 60 km, while those for sand range from 0.4 to 113 km. Mean sediment velocities for silt-clay range from 0.0072 km/yr to 0.12 km/yr, while those for sand range from 0.0008 km/yr to 0.20 km/yr, 4-6 orders of magnitude slower than the velocity of water in the channel. These results suggest lag times of 100-1000 years between BMP implementation and effectiveness in receiving waters such as the Chesapeake Bay (where BMPs are located upstream of the characteristic transport length scale). Many particles likely travel much faster than these average values, so further research is needed to determine the complete distribution of suspended sediment velocities in real watersheds.

  7. Magneto-Induced ac Electrical Permittivity of Metal-Dielectric Composites with a Two Characteristic Length Scales Periodic Microstructure

    International Nuclear Information System (INIS)

    A new effect was recently predicted in conducting composites that have a periodic microstructure: an induced strongly anisotropic dc magneto-resistance. This phenomenon is already verified on high mobility n-GaAs films. Here we discuss the possibility of observing analogous behavior in the ac electric permittivity of a metal-dielectric composite with a periodic microstructure in the presence of a strong magnetic field. We developed new analytical and numerical methods to treat the low-frequency magneto-optical properties in composite media with both disordered and periodic conducting micro-structures. Those methods allow us to study composites with inclusions of arbitrary shape (and arbitrary volume fraction) at arbitrarily strong magnetic field. This is exploited in order to calculate an effective dielectric tensor for this system as a function of applied magnetic field and ac frequency. We show that in a non-dilute metal-dielectric composite medium the magneto-plasma resonance and the cyclotron resonance depend upon both the applied magnetic field as well as on the geometric shape of the inclusion. Near such a resonance, it is possible to achieve large values for the ratio of the off-diagonal-to-diagonal electric permittivity tensor components, εxy/εxx, (since εxx→0, while εxy≠0), which is analogous to similar ratio of the resistivity tensor components, ρxy/ρxx, in the case of dc magneto-transport problem. Motivated by this observation and by results of previous studies of dc magneto-transport in composite conductors, we then performed a numerical study of the ac magneto-electric properties of a particular metal-dielectric composite film with a periodic columnar microstructure which has a two characteristic length scales. The unit cell of such composite is prepared as follows: We placed the conducting square (in cross section) rods (first characteristic length scale) along the perimeter of the unit cell in order to create a dielectric host with large

  8. On determining characteristic length scales in pressure-gradient turbulent boundary layers

    Science.gov (United States)

    Vinuesa, R.; Bobke, A.; Örlü, R.; Schlatter, P.

    2016-05-01

    In the present work, we analyze three commonly used methods to determine the edge of pressure gradient turbulent boundary layers: two based on composite profiles, the one by Chauhan et al. ["Criteria for assessing experiments in zero pressure gradient boundary layers," Fluid Dyn. Res. 41, 021404 (2009)] and the one by Nickels ["Inner scaling for wall-bounded flows subject to large pressure gradients," J. Fluid Mech. 521, 217-239 (2004)], and the other one based on the condition of vanishing mean velocity gradient. Additionally, a new method is introduced based on the diagnostic plot concept by Alfredsson et al. ["A new scaling for the streamwise turbulence intensity in wall-bounded turbulent flows and what it tells us about the `outer' peak," Phys. Fluids 23, 041702 (2011)]. The boundary layers developing over the suction and pressure sides of a NACA4412 wing section, extracted from a direct numerical simulation at chord Reynolds number Rec = 400 000, are used as the test case, besides other numerical and experimental data from favorable, zero, and adverse pressure-gradient flat-plate turbulent boundary layers. We find that all the methods produce robust results with mild or moderate pressure gradients, although the composite-profile techniques require data preparation, including initial estimations of fitting parameters and data truncation. Stronger pressure gradients (with a Rotta-Clauser pressure-gradient parameter β larger than around 7) lead to inconsistent results in all the techniques except the diagnostic plot. This method also has the advantage of providing an objective way of defining the point where the mean streamwise velocity is 99% of the edge velocity and shows consistent results in a wide range of pressure gradient conditions, as well as flow histories. Collapse of intermittency factors obtained from a wide range of pressure-gradient and Re conditions on the wing further highlights the robustness of the diagnostic plot method to determine the

  9. Characteristic length scale of the magnon accumulation in Fe3O4/Pt bilayer structures by incoherent thermal excitation

    Science.gov (United States)

    Anadón, A.; Ramos, R.; Lucas, I.; Algarabel, P. A.; Morellón, L.; Ibarra, M. R.; Aguirre, M. H.

    2016-07-01

    The dependence of Spin Seebeck effect (SSE) with the thickness of the magnetic materials is studied by means of incoherent thermal excitation. The SSE voltage signal in Fe3O4/Pt bilayer structure increases with the magnetic material thickness up to 100 nm, approximately, showing signs of saturation for larger thickness. This dependence is well described in terms of a spin current pumped in the platinum film by the magnon accumulation in the magnetic material. The spin current is generated by a gradient of temperature in the system and detected by the Pt top contact by means of inverse spin Hall effect. Calculations in the frame of the linear response theory adjust with a high degree of accuracy the experimental data, giving a thermal length scale of the magnon accumulation (Λ) of 17 ± 3 nm at 300 K and Λ = 40 ± 10 nm at 70 K.

  10. Dynamics of lithium ions in borotellurite mixed former glasses: Correlation between the characteristic length scales of mobile ions and glass network structural units

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, A.; Ghosh, A., E-mail: sspag@iacs.res.in [Department of Solid State Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)

    2014-10-28

    We have studied the mixed network former effect on the dynamics of lithium ions in borotellurite glasses in wide composition and temperature ranges. The length scales of ion dynamics, such as characteristic mean square displacement and spatial extent of sub-diffusive motion of lithium ions have been determined from the ac conductivity and dielectric spectra, respectively, in the framework of linear response theory. The relative concentrations of different network structural units have been determined from the deconvolution of the FTIR spectra. A direct correlation between the ion dynamics and the characteristic length scales and the relative concentration of BO{sub 4} units has been established for different compositions of the borotellurite glasses.

  11. Scaling of avian primary feather length

    OpenAIRE

    Nudds, Robert L.; Kaiser, Gary V.; Dyke, Gareth J.

    2011-01-01

    The evolution of the avian wing has long fascinated biologists, yet almost no work includes the length of primary feathers in consideration of overall wing length variation. Here we show that the length of the longest primary feather ( ) contributing to overall wing length scales with negative allometry against total arm (ta = humerus+ulna+manus). The scaling exponent varied slightly, although not significantly so, depending on whether a species level analysis was used or phylogeny was contro...

  12. A multiple length scale correlation operator for ocean data assimilation

    Directory of Open Access Journals (Sweden)

    Isabelle Mirouze

    2016-02-01

    Full Text Available Ocean data assimilation systems can take into account time and space scale variations by representing background error covariance functions with more complex shapes than the classical Gaussian function. In particular, the construction of the correlation functions can be improved to give more flexibility. We describe a correlation operator that features high correlations within a short scale and weak correlations within a larger scale. This multiple length scale correlation operator is defined as a linear combination of Whittle–Matérn functions with different length scales. The main characteristics of the resulting correlation function are described. In particular, a focus is given on features that might be of interest to determine the parameters of the model: the Daley length scale, the normalised spectrum inflexion point and the kurtosis coefficient.The multiple length scale operator has been implemented in NEMOVAR, a variational ocean data assimilation system. A dual length scale formulation was tested in a one-year reanalysis and compared with a single length scale formulation. The results emphasise the importance of estimating with great care the factors used within the combination. They also demonstrate the potential of the dual length scale formulation, in particular through a decrease of the innovation statistics for salinity profiles. The dual length scale formulation is now operational at the Met Office.

  13. Mixing lengths scaling in a gravity flow

    Energy Technology Data Exchange (ETDEWEB)

    Ecke, Robert E [Los Alamos National Laboratory; Rivera, Micheal [Los Alamos National Laboratory; Chen, Jun [Los Alamos National Laboratory; Ecke, Robert E [Los Alamos National Laboratory

    2009-01-01

    We present an experimental study of the mixing processes in a gravity current. The turbulent transport of momentum and buoyancy can be described in a very direct and compact form by a Prandtl mixing length model [1]: the turbulent vertical fluxes of momentum and buoyancy are found to scale quadraticatly with the vertical mean gradients of velocity and density. The scaling coefficient is the square of the mixing length, approximately constant over the mixing zone of the stratified shear layer. We show in this paper how, in different flow configurations, this length can be related to the shear length of the flow {radical}({var_epsilon}/{partial_derivative}{sub z}u{sup 3}).

  14. Minimal Length Scale Scenarios for Quantum Gravity

    Directory of Open Access Journals (Sweden)

    Sabine Hossenfelder

    2013-01-01

    Full Text Available We review the question of whether the fundamental laws of nature limit our ability to probe arbitrarily short distances. First, we examine what insights can be gained from thought experiments for probes of shortest distances, and summarize what can be learned from different approaches to a theory of quantum gravity. Then we discuss some models that have been developed to implement a minimal length scale in quantum mechanics and quantum field theory. These models have entered the literature as the generalized uncertainty principle or the modified dispersion relation, and have allowed the study of the effects of a minimal length scale in quantum mechanics, quantum electrodynamics, thermodynamics, black-hole physics and cosmology. Finally, we touch upon the question of ways to circumvent the manifestation of a minimal length scale in short-distance physics.

  15. Topographical length scales of hierarchical superhydrophobic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Dhillon, P.K. [Department of Physics, Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab 140001 (India); Brown, P.S.; Bain, C.D.; Badyal, J.P.S. [Department of Chemistry, Science Laboratories, Durham University, Durham DH1 3LE, England (United Kingdom); Sarkar, S., E-mail: sarkar@iitrpr.ac.in [Department of Physics, Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab 140001 (India)

    2014-10-30

    Highlights: • Hydrophobic CF{sub 4} plasma fluorinated polybutadiene surfaces has been characterised using AFM. • Micro, Nano, and Micro + Nano topographies generated by altering plasma power and duration. • Dynamic scaling theory and FFT analysis used to characterize these surfaces quantitatively. • Roughnesses are different for different length scales of the surfaces considered. • Highest local roughness obtained from scaling analysis for shorter length scales of about 500 nm explains the superhydrophobicity for the Micro + Nano surface. - Abstract: The morphology of hydrophobic CF{sub 4} plasma fluorinated polybutadiene surfaces has been characterised using atomic force microscopy (AFM). Judicious choice of the plasma power and exposure duration leads to formation of three different surface morphologies (Micro, Nano, and Micro + Nano). Scaling theory analysis shows that for all three surface topographies, there is an initial increase in roughness with length scale followed by a levelling-off to a saturation level. At length scales around 500 nm, it is found that the roughness is very similar for all three types of surfaces, and the saturation roughness value for the Micro + Nano morphology is found to be intermediate between those for the Micro and Nano surfaces. Fast Fourier Transform (FFT) analysis has shown that the Micro + Nano topography comprises a hierarchical superposition of Micro and Nano morphologies. Furthermore, the Micro + Nano surfaces display the highest local roughness (roughness exponent α = 0.42 for length scales shorter than ∼500 nm), which helps to explain their superhydrophobic behaviour (large water contact angle (>170°) and low hysteresis (<1°))

  16. Scaling of avian primary feather length.

    Directory of Open Access Journals (Sweden)

    Robert L Nudds

    Full Text Available The evolution of the avian wing has long fascinated biologists, yet almost no work includes the length of primary feathers in consideration of overall wing length variation. Here we show that the length of the longest primary feather (f(prim contributing to overall wing length scales with negative allometry against total arm (ta = humerus+ulna+manus. The scaling exponent varied slightly, although not significantly so, depending on whether a species level analysis was used or phylogeny was controlled for using independent contrasts: f(prim is proportional to ta(0.78-0.82. The scaling exponent was not significantly different from that predicted (0.86 by earlier work. It appears that there is a general trend for the primary feathers of birds to contribute proportionally less, and ta proportionally more, to overall wingspan as this dimension increases. Wingspan in birds is constrained close to mass (M(1/3 because of optimisation for lift production, which limits opportunities for exterior morphological change. Within the wing, variations in underlying bone and feather lengths nevertheless may, in altering the joint positions, permit a range of different flight styles by facilitating variation in upstroke kinematics.

  17. Length-scale dependent phonon interactions

    CERN Document Server

    Srivastava, Gyaneshwar

    2014-01-01

    This book presents  a comprehensive description of phonons and their interactions in systems with different dimensions and length scales. Internationally-recognized leaders describe theories and measurements of phonon interactions  in relation to the design of materials with exotic properties such as metamaterials, nano-mechanical systems, next-generation electronic, photonic, and acoustic devices, energy harvesting, optical information storage, and applications of phonon lasers in a variety of fields. The emergence of techniques for control of semiconductor properties and geometry has enabled engineers to design structures in which functionality is derived from controlling electron behavior. As manufacturing techniques have greatly expanded the list of available materials and the range of attainable length scales, similar opportunities now exist for designing devices whose functionality is derived from controlling phonon behavior. However, progress in this area is hampered by gaps in our knowledge of phono...

  18. Hydrodynamic length-scale selection in microswimmer suspensions

    Science.gov (United States)

    Heidenreich, Sebastian; Dunkel, Jörn; Klapp, Sabine H. L.; Bär, Markus

    2016-08-01

    A universal characteristic of mesoscale turbulence in active suspensions is the emergence of a typical vortex length scale, distinctly different from the scale invariance of turbulent high-Reynolds number flows. Collective length-scale selection has been observed in bacterial fluids, endothelial tissue, and active colloids, yet the physical origins of this phenomenon remain elusive. Here, we systematically derive an effective fourth-order field theory from a generic microscopic model that allows us to predict the typical vortex size in microswimmer suspensions. Building on a self-consistent closure condition, the derivation shows that the vortex length scale is determined by the competition between local alignment forces, rotational diffusion, and intermediate-range hydrodynamic interactions. Vortex structures found in simulations of the theory agree with recent measurements in Bacillus subtilis suspensions. Moreover, our approach yields an effective viscosity enhancement (reduction), as reported experimentally for puller (pusher) microorganisms.

  19. Quantum criticality with two length scales

    Science.gov (United States)

    Shao, Hui; Guo, Wenan; Sandvik, Anders W.

    2016-04-01

    The theory of deconfined quantum critical (DQC) points describes phase transitions at absolute temperature T = 0 outside the standard paradigm, predicting continuous transformations between certain ordered states where conventional theory would require discontinuities. Numerous computer simulations have offered no proof of such transitions, instead finding deviations from expected scaling relations that neither were predicted by the DQC theory nor conform to standard scenarios. Here we show that this enigma can be resolved by introducing a critical scaling form with two divergent length scales. Simulations of a quantum magnet with antiferromagnetic and dimerized ground states confirm the form, proving a continuous transition with deconfined excitations and also explaining anomalous scaling at T > 0. Our findings revise prevailing paradigms for quantum criticality, with potential implications for many strongly correlated materials.

  20. On a continuum model of an intrinsic length scale

    International Nuclear Information System (INIS)

    A phenomenological model has been developed which modifies the constitutive equations of a general continuum to include the dynamic dispersive effects of a an intrinsic characteristic length scale. The new terms in this model are nondissipative and they are characterized by a single material constant. Moreover, the modified model requires no additional initial or boundary conditions. Here, an example problem of dynamic simple shearing of a metal with a discontinuity in yield strength is considered to show how these new terms control strain localization. The results of the modified theory for a rate-independent plastic material are compared with those of a viscoplastic material with no intrinsic length scale. (orig.)

  1. Scale Length of the Galactic Thin Disk

    Indian Academy of Sciences (India)

    D. Κ. Ojha

    2000-06-01

    This paper presents an analysis of the first 2MASS (The Two Micron All Sky Survey) sampler data as observed at lower Galactic latitude in our Galaxy. These new near-infrared data provide insight into the structure of the thin disk of our Galaxy, The interpretation of star counts and color distributions of stars in the near-infrared with the synthetic stellar population model, gives strong evidence that the Galactic thin disk density scale length, ℎ, is rather short (2.7 ± 0.1 kpc).

  2. The existence of a critical length scale in regularised friction

    CERN Document Server

    Kammer, David S; Anciaux, Guillaume; Molinari, Jean-Francois

    2014-01-01

    We study a regularisation of Coulomb's friction law on the propagation of local slip at an interface between a deformable and a rigid solid. This regularisation, which was proposed based on experimental observations, smooths the effect of a sudden jump in the contact pressure over a characteristic length scale. We apply it in numerical simulations in order to analyse its influence on the behaviour of local slip. We first show that mesh convergence in dynamic simulations is achieved without any numerical damping in the bulk and draw a convergence map with respect to the characteristic length of the friction regularisation. By varying this length scale on the example of a given slip event, we observe that there is a critical length below which the friction regularisation does not affect anymore the propagation of the interface rupture. A spectral analysis of the regularisation on a periodic variation of Coulomb's friction is conducted to confirm the existence of this critical length. The results indicate that i...

  3. Critical length scale controls adhesive wear mechanisms

    Science.gov (United States)

    Aghababaei, Ramin; Warner, Derek H.; Molinari, Jean-Francois

    2016-06-01

    The adhesive wear process remains one of the least understood areas of mechanics. While it has long been established that adhesive wear is a direct result of contacting surface asperities, an agreed upon understanding of how contacting asperities lead to wear debris particle has remained elusive. This has restricted adhesive wear prediction to empirical models with limited transferability. Here we show that discrepant observations and predictions of two distinct adhesive wear mechanisms can be reconciled into a unified framework. Using atomistic simulations with model interatomic potentials, we reveal a transition in the asperity wear mechanism when contact junctions fall below a critical length scale. A simple analytic model is formulated to predict the transition in both the simulation results and experiments. This new understanding may help expand use of computer modelling to explore adhesive wear processes and to advance physics-based wear laws without empirical coefficients.

  4. Instability of Stratified Shear Flow: Intermittency and Length Scales

    Science.gov (United States)

    Ecke, Robert; Odier, Philippe

    2015-11-01

    The stability of stratified shear flows which occur in oceanic overflows, wind-driven thermoclines, and atmospheric inversion layers is governed by the Richardson Number Ri , a non-dimensional balance between stabilizing stratification and destabilizing shear. For a shear flow with velocity difference U, density difference Δρ and characteristic length H, one has Ri = g (Δρ / ρ) H /U2 . A more precise definition is the gradient Richardson Number Rig =N2 /S2 where the buoyancy frequency N =√{ (g / ρ) ∂ρ / ∂z } , the mean strain S = ∂U / ∂z with z parallel to gravity and with ensemble or time averages defining the gradients. We explore the stability and mixing properties of a wall-bounded shear flow for 0 . 1 < Rig < 1 using simultaneous measurements of density and velocity fields. The flow, confined from the top by a horizontal boundary, is a lighter alcohol-water mixture injected from a nozzle into quiescent heavier salt-water fluid. The injected flow is turbulent with Taylor Reynolds number about 75. We compare a set of length scales that characterize the mixing properties of our turbulent stratified shear flow including Thorpe Length LT, Ozmidov Length LO, and Ellison Length LE.

  5. Eddy length scales in the North Atlantic Ocean

    OpenAIRE

    Eden, Carsten

    2007-01-01

    Eddy length scales are calculated from satellite altimeter products and in an eddy-resolving model of the North Atlantic Ocean. Four different measures for eddy length scales are derived from kinetic energy densities in wave number space and spatial decorrelation scales. Observational estimates and model simulation agree well in all these measures near the surface. As found in previous studies, all length scales are, in general, decreasing with latitude. They are isotropic and proportional to...

  6. Experimental evidence for two thermodynamic length scales in neutralized polyacrylate gels

    Science.gov (United States)

    Horkay, Ferenc; Hecht, Anne-Marie; Grillo, Isabelle; Basser, Peter J.; Geissler, Erik

    2002-11-01

    The small angle neutron scattering (SANS) behavior of fully neutralized sodium polyacrylate gels is investigated in the presence of calcium ions. Analysis of the SANS response reveals the existence of three characteristic length scales, two of which are of thermodynamic origin, while the third length is associated with the frozen-in structural inhomogeneities. This latter contribution exhibits power law behavior with a slope of about -3.6, reflecting the presence of interfaces. The osmotically active component of the scattering signal is defined by two characteristic length scales, a correlation length ξ and a persistence length L.

  7. How Cells Measure Length on Subcellular Scales.

    Science.gov (United States)

    Marshall, Wallace F

    2015-12-01

    Cells are not just amorphous bags of enzymes, but precise and complex machines. With any machine, it is important that the parts be of the right size, yet our understanding of the mechanisms that control size of cellular structures remains at a rudimentary level in most cases. One problem with studying size control is that many cellular organelles have complex 3D structures that make their size hard to measure. Here we focus on linear structures within cells, for which the problem of size control reduces to the problem of length control. We compare and contrast potential mechanisms for length control to understand how cells solve simple geometry problems. PMID:26437596

  8. Change of characteristic length with packaging for torsional MEMS switch

    Science.gov (United States)

    Bansal, Deepak; Anuroop, Kumar, Prem; Kaur, Maninder; Gaur, Surender; Kothari, Prateek; Singh, Arvind K.; Rangra, Kamaljit

    2016-04-01

    Fluid continuity theory is used to describe the dynamic response of open Micro-Electro-Mechanical-System (MEMS) devices. For a packaged device, at low pressure, the fluid continuity theory is no longer valid and a rarefication theory based on a Knudsen number is used. In an open MEMS device, the characteristic length which determines the Knudsen number is represented by the gap between the MEMS bridge and underneath actuation electrodes. On the other hand, for a packaged device, effective characteristic length is modified with the packaging cavity height. In this paper, for a packaged MEMS device, effective characteristic length with reference to the packaging height is derived.

  9. On the length scale dependence of microscopic strain by SANS

    OpenAIRE

    Westermann, S; PYCKHOUT-HINTZEN, W.; Richter, D.; Straube, E.; Egelhaaf, S.; May, R.

    2001-01-01

    We present a SANS study on the length scale dependence of chain deformation patterns in dense cross-linked elastomers. Three different polyisoprene networks of long primary block-copolymer chains of the HDH-type were analyzed. The total length of the primary chains is identical, while the length of the deuterated middle block was varied in order to cover several length scale regimes of interest. The scattering data are analyzed in the frame of the tube model of rubber elasticity in combinatio...

  10. Dynamic Leidenfrost effect: relevant time- and length-scales

    CERN Document Server

    Shirota, Minori; Sun, Chao; Prosperetti, Andrea; Lohse, Detlef

    2015-01-01

    When a liquid droplet impacts a hot solid surface, enough vapor may be generated under it as to prevent its contact with the solid. The minimum solid temperature for this so-called Leidenfrost effect to occur is termed the Leidenfrost temperature, or the dynamic Leidenfrost temperature when the droplet velocity is non-negligible. We observe the wetting/drying and the levitation dynamics of the droplet impacting on an (isothermal) smooth sapphire surface using high speed total internal reflection imaging, which enables us to observe the droplet base up to about 100 nm above the substrate surface. By this method we are able to reveal the processes responsible for the transitional regime between the fully wetting and the fully levitated droplet as the solid temperature increases, thus shedding light on the characteristic time- and length-scales setting the dynamic Leidenfrost temperature for droplet impact on an isothermal substrate.

  11. Permeability Description by Characteristic Length, Tortuosity, Constriction and Porosity

    CERN Document Server

    Berg, Carl Fredrik

    2015-01-01

    In this article we investigate the permeability of a porous medium as given in Darcy's law. The permeability is described by an effective hydraulic pore radius in the porous medium, the fluctuation in local hydraulic pore radii, the length of streamlines, and the fractional volume conducting flow. The effective hydraulic pore radius is related to a characteristic hydraulic length, the fluctuation in local hydraulic radii is related to a constriction factor, the length of streamlines is characterized by a tortuosity, and the fractional volume conducting flow from inlet to outlet is described by an effective porosity. The characteristic length, the constriction factor, the tortuosity and the effective porosity are thus intrinsic descriptors of the pore structure relative to direction. We show that the combined effect of our pore structure description fully describes the permeability of a porous medium. The theory is applied to idealized porous media, where it reproduces Darcy's law for fluid flow derived from t...

  12. Scale Length of Disk Galaxies in the Local Universe

    CERN Document Server

    Fathi, Kambiz

    2011-01-01

    Disk scale length and central surface brightness for a sample of about 29955 bright disk galaxies from the Sloan Digital Sky Survey have been analysed. Cross correlation of the SDSS sample with the LEDA catalogue allowed us to investigate the variation of the scale lengths for different types of disk/spiral galaxies and present distributions and typical trends of scale lengths all the SDSS bands with linear relations that indicate the relation that connect scale lengths in one passband to another. We use the volume corrected results in the r-band and revisit the relation between these parameters and the galaxy morphology. The derived scale lengths presented here are representative for a typical galaxy mass of 10^10.8 solarmasses, and the RMS dispersion is larger for more massive galaxies. We analyse the scale-length-central disk brightness plane and further investigate the Freeman Law and confirm that it indeed defines an upper limit for disk central surface brightness in bright disks (r 6) have fainter centr...

  13. Generation of Length Distribution, Length Diagram, Fibrogram, and Statistical Characteristics by Weight of Cotton Blends

    Directory of Open Access Journals (Sweden)

    B. Azzouz

    2007-01-01

    Full Text Available The textile fibre mixture as a multicomponent blend of variable fibres imposes regarding the proper method to predict the characteristics of the final blend. The length diagram and the fibrogram of cotton are generated. Then the length distribution, the length diagram, and the fibrogram of a blend of different categories of cotton are determined. The length distributions by weight of five different categories of cotton (Egyptian, USA (Pima, Brazilian, USA (Upland, and Uzbekistani are measured by AFIS. From these distributions, the length distribution, the length diagram, and the fibrogram by weight of four binary blends are expressed. The length parameters of these cotton blends are calculated and their variations are plotted against the mass fraction x of one component in the blend .These calculated parameters are compared to those of real blends. Finally, the selection of the optimal blends using the linear programming method, based on the hypothesis that the cotton blend parameters vary linearly in function of the components rations, is proved insufficient.

  14. Spin echo diffraction in disordered media with single length scales

    International Nuclear Information System (INIS)

    The spin echo diffraction observed in a pulsed field gradient NMR experiment is studied by simulation in computer generated two-dimensional disordered porous media characterized by a single length scale such as their mean pore diameter. In the propagator formulation of the pulsed field gradient experiments carried out in fluids confined inside porous media one expects to see a diffraction pattern characterizing the above length scale. We have explored the possibility of using this echo diffraction technique as a practical noninvasive tool to extract information about the pore geometries. It turns out that even for a disordered medium, the echo-diffraction pattern picks up the dominant length scale. copyright 1997 The American Physical Society

  15. Magnetically stabilized bed dust filters-Analysis through variable length scale approach

    Institute of Scientific and Technical Information of China (English)

    Jordan; Hristov

    2007-01-01

    Magnetically stabilized beds are packed beds subjected to fluid-driven deformation and controlled by magnetically induced interparticle forces.This paper deals with magnetically stabilized beds as deformable porous media and describes their application in dust filtration. The Richardson-Zaki scaling law, U/Ut = εn describes the field controlled bed expansion via the exponent n, that yields a porosity-dependent flow length scale dc =dpεn.The paper addresses two issues: (i) deformation characteristics by assuming homogeneous bed expansion and a definition of bed variable flow length scale; (ii) dust filtration characteristics such as filter coefficient, specific deposit and filtration efficiency expressed in terms of the variable flow length scale and illustrated by experimental data.

  16. Interpretation of Quantum Field Theories with a Minimal Length Scale

    OpenAIRE

    Hossenfelder, S.

    2006-01-01

    It has been proposed that the incorporation of an observer independent minimal length scale into the quantum field theories of the standard model effectively describes phenomenological aspects of quantum gravity. The aim of this paper is to interpret this description and its implications for scattering processes.

  17. Size effects and internal length scales in the elasticity of random fiber networks

    Science.gov (United States)

    Picu, Catalin; Berkache, Kamel; Shahsavari, Ali; Ganghoffer, Jean-Francois

    Random fiber networks are the structural element of many biological and man-made materials, including connective tissue, various consumer products and packaging materials. In all cases of practical interest the scale at which the material is used and the scale of the fiber diameter or the mean segment length of the network are separated by several orders of magnitude. This precludes solving boundary value problems defined on the scale of the application while resolving every fiber in the system, and mandates the development of continuum equivalent models. To this end, we study the intrinsic geometric and mechanical length scales of the network and the size effect associated with them. We consider both Cauchy and micropolar continuum models and calibrate them based on the discrete network behavior. We develop a method to predict the characteristic length scales of the problem and the minimum size of a representative element of the network based on network structural parameters and on fiber properties.

  18. Multiple-length-scale deformation analysis in a thermoplastic polyurethane.

    Science.gov (United States)

    Sui, Tan; Baimpas, Nikolaos; Dolbnya, Igor P; Prisacariu, Cristina; Korsunsky, Alexander M

    2015-01-01

    Thermoplastic polyurethane elastomers enjoy an exceptionally wide range of applications due to their remarkable versatility. These block co-polymers are used here as an example of a structurally inhomogeneous composite containing nano-scale gradients, whose internal strain differs depending on the length scale of consideration. Here we present a combined experimental and modelling approach to the hierarchical characterization of block co-polymer deformation. Synchrotron-based small- and wide-angle X-ray scattering and radiography are used for strain evaluation across the scales. Transmission electron microscopy image-based finite element modelling and fast Fourier transform analysis are used to develop a multi-phase numerical model that achieves agreement with the combined experimental data using a minimal number of adjustable structural parameters. The results highlight the importance of fuzzy interfaces, that is, regions of nanometre-scale structure and property gradients, in determining the mechanical properties of hierarchical composites across the scales. PMID:25758945

  19. Characteristic Scales in Galaxy Formation

    OpenAIRE

    Dekel, Avishai

    2004-01-01

    Recent data, e.g. from SDSS and 2dF, reveal a robust bi-modality in the distribution of galaxy properties, with a characteristic transition scale at stellar mass M_*~3x10^{10} Msun (near L_*), corresponding to virial velocity V~100 km/s. Smaller galaxies tend to be blue disks of young populations. They define a "fundamental line" of decreasing surface brightness, metallicity and velocity with decreasing M_*, which extends to the smallest dwarf galaxies. Galaxies above the critical scale are d...

  20. Topology, length scales, and energetics of surfactant micelles.

    Science.gov (United States)

    Dhakal, Subas; Sureshkumar, Radhakrishna

    2015-07-14

    We study the morphology, energetics, and kinetics of a self-associating model cationic surfactant in water using large-scale coarse-grained molecular dynamics simulations over time scales that allow for probing micelle recombination dynamics. We develop an algorithm to track micelle contours and quantify various microstructural features such as contour length distribution, persistence length, and mesh size. We predict reliably the end-cap energy and recombination time of micelles, directly from molecular simulations for the first time. We further consider the variation of solution viscosity as a function of salt concentration and show that branched and multiconnected structures govern the experimentally observed anomalous dependence of zero-shear viscosity on salt concentration. Overall, simulation predictions are in good agreement with experiments. PMID:26178125

  1. Emergence of Chirality from Isotropic Interactions of Three Length Scales

    Science.gov (United States)

    Mkhonta, S. K.; Elder, K. R.; Huang, Zhi-Feng

    2016-05-01

    Chirality is known to play a pivotal role in determining material properties and functionalities. However, it remains a great challenge to understand and control the emergence of chirality and the related enantioselective process particularly when the building components of the system are achiral. Here we explore the generic mechanisms driving the formation of two-dimensional chiral structures in systems characterized by isotropic interactions and three competing length scales. We demonstrate that starting from isotropic and rotationally invariant interactions, a variety of chiral ordered patterns and superlattices with anisotropic but achiral units can self-assemble. The mechanisms for selecting specific states are related to the length-scale coupling and the selection of resonant density wave vectors. Sample phase diagrams and chiral elastic properties are identified. These findings provide a viable route for predicting chiral phases and selecting the desired handedness.

  2. Growing length and time scales in glass-forming liquids

    OpenAIRE

    Karmakar, Smarajit; Dasgupta, Chandan; Sastry, Srikanth

    2009-01-01

    The glass transition, whereby liquids transform into amorphous solids at low temperatures, is a subject of intense research despite decades of investigation. Explaining the enormous increase in relaxation times of a liquid upon supercooling is essential for understanding the glass transition. Although many theories, such as the Adam–Gibbs theory, have sought to relate growing relaxation times to length scales associated with spatial correlations in liquid structure or motion of molecules, the...

  3. Transition in multiple-scale-lengths turbulence in plasmas

    International Nuclear Information System (INIS)

    The statistical theory of strong turbulence in inhomogeneous plasmas is developed for the cases where fluctuations with different scale-lengths coexist. Statistical nonlinear interactions between semi-micro and micro modes are first kept in the analysis as the drag, noise and drive. The nonlinear dynamics determines both the fluctuation levels and the cross field turbulent transport for the fixed global parameters. A quenching or suppressing effect is induced by their nonlinear interplay, even if both modes are unstable when analyzed independently. Influence of the inhomogeneous global radial electric field is discussed. A new insight is given for the physics of internal transport barrier. The thermal fluctuation of the scale length of λD is assumed to be statistically independent. The hierarchical structure is constructed according to the scale lengths. Transitions in turbulence are found and phase diagrams with cusp type catastrophe are obtained. Dynamics is followed. Statistical properties of the subcritical excitation are discussed. The probability density function (PDF) and transition probability are obtained. Power-laws are obtained in the PDF as well as in the transition probability. Generalization for the case where turbulence is composed of three-classes of modes is also developed. A new catastrophe of turbulent sates is obtained. (author)

  4. Discrimination between earthquakes and explosions using Markov Length Scale (MLS)

    International Nuclear Information System (INIS)

    Full text: In this paper, the Markov length (time) scale are regarded as the discriminating tools to classify the natural seismic events (earthquakes) from the artificial ones (nuclear explosions) based on the seismic signals recorded at teleseismic distances. The bulk of our novel is to improve the obtained numerical results using this advance technique. For the Markov length scale, by testing the different types of seismic features, we have shown the potential application of this method to discriminate the classes. During the above study, we found out that the Markov length scale (MLS) has been used in a fully innovative manner in this work. Here the MLS detects the type of the source whenever a natural or artificial source changes the nature of the background noise of the seismograms. During the above study, we found out that MLS is sometimes capable to alarm the further natural seismological events just a little before the onset. So the application of MLS in seismic prediction is also studied through the simulated experiments. (author)

  5. CHARACTERISTIC LENGTH OF ENERGY-CONTAINING STRUCTURES AT THE BASE OF A CORONAL HOLE

    International Nuclear Information System (INIS)

    An essential parameter for models of coronal heating and fast solar wind acceleration that rely on the dissipation of MHD turbulence is the characteristic energy-containing length λ of the squared velocity and magnetic field fluctuations (u2 and b2) transverse to the mean magnetic field inside a coronal hole (CH) at the base of the corona. The characteristic length scale directly defines the heating rate. We use a time series analysis of solar granulation and magnetic field measurements inside two CHs obtained with the New Solar Telescope at Big Bear Solar Observatory. A data set for transverse magnetic fields obtained with the Solar Optical Telescope/Spectro-Polarimeter on board the Hinode spacecraft was utilized to analyze the squared transverse magnetic field fluctuations bt2. Local correlation tracking was applied to derive the squared transverse velocity fluctuations u 2. We find that for u 2 structures, the Batchelor integral scale λ varies in a range of 1800-2100 km, whereas the correlation length sigmav and the e-folding length L vary between 660 and 1460 km. Structures for bt2 yield λ ≈ 1600 km, sigmav ≈ 640 km, and L ≈ 620 km. An averaged (over λ, sigmav, and L) value of the characteristic length of u 2 fluctuations is 1260 ± 500 km, and that of bt2 is 950 ± 560 km. The characteristic length scale in the photosphere is approximately 1.5-50 times smaller than that adopted in previous models (3-30 × 103 km). Our results provide a critical input parameter for current models of coronal heating and should yield an improved understanding of fast solar wind acceleration

  6. Characteristic Scales in Galaxy Formation

    CERN Document Server

    Dekel, A

    2004-01-01

    Recent data, e.g. from SDSS and 2dF, reveal a robust bi-modality in the distribution of galaxy properties, with a characteristic transition scale at stellar mass M_*~3x10^{10} Msun (near L_*), corresponding to virial velocity V~100 km/s. Smaller galaxies tend to be blue disks of young populations. They define a "fundamental line" of decreasing surface brightness, metallicity and velocity with decreasing M_*, which extends to the smallest dwarf galaxies. Galaxies above the critical scale are dominated by red spheroids of old populations, with roughly constant high surface brightens and metallicity, and they tend to host AGNs. A minimum in the virial M/L is obtained at the same magic scale. This bi-modality can be the combined imprint of several different physical processes. On smaller scales, disks are built by cold flows, and supernova feedback is effective in regulating star formation. On larger scales, the infalling gas is heated by a virial shock and star formation can be suppressed by AGN feedback. Anothe...

  7. Similarity theory based on the Dougherty-Ozmidov length scale

    CERN Document Server

    Grachev, Andrey A; Fairall, Christopher W; Guest, Peter S; Persson, P Ola G

    2014-01-01

    Local similarity theory is suggested based on the Brunt-Vaisala frequency and the dissipation rate of turbulent kinetic energy instead the turbulent fluxes used in the traditional Monin-Obukhov similarity theory. Based on dimensional analysis (Pi theorem), it is shown that any properly scaled statistics of the small-scale turbulence are universal functions of a stability parameter defined as the ratio of a reference height z and the Dougherty-Ozmidov length scale which in the limit of z-less stratification is linearly proportional to the Obukhov length scale. Measurements of atmospheric turbulence made at five levels on a 20-m tower over the Arctic pack ice during the Surface Heat Budget of the Arctic Ocean experiment (SHEBA) are used to examine the behaviour of different similarity functions in the stable boundary layer. It is found that in the framework of this approach the non-dimensional turbulent viscosity is equal to the gradient Richardson number whereas the non-dimensional turbulent thermal diffusivit...

  8. Multi length-scale characterisation inorganic materials series

    CERN Document Server

    Bruce, Duncan W; Walton, Richard I

    2013-01-01

    Whereas the first five volumes in the Inorganic Materials Series focused on particular classes of materials (synthesis, structures, chemistry, and properties), it is now very timely to provide complementary volumes that introduce and review state-of-the-art techniques for materials characterization. This is an important way of emphasizing the interplay of chemical synthesis and physical characterization. The methods reviewed include spectroscopic, diffraction, and surface techniques that examine the structure of materials on all length scales, from local atomic structure to long-range crystall

  9. Natural Length Scales of Ecological Systems: Applications at Community and Ecosystem Levels

    Directory of Open Access Journals (Sweden)

    Craig R. Johnson

    2009-06-01

    Full Text Available The characteristic, or natural, length scales of a spatially dynamic ecological landscape are the spatial scales at which the deterministic trends in the dynamic are most sharply in focus. Given recent development of techniques to determine the characteristic length scales (CLSs of real ecological systems, I explore the potential for using CLSs to address three important and vexing issues in applied ecology, viz. (i determining the optimum scales to monitor ecological systems, (ii interpreting change in ecological communities, and (iii ascertaining connectivity between species in complex ecologies. In summarizing the concept of characteristic length scales as system-level scaling thresholds, I emphasize that the primary CLS is, by definition, the optimum scale at which to monitor a system if the objective is to observe its deterministic dynamics at a system level. Using several different spatially explicit individual-based models, I then explore predictions of the underlying theory of CLSs in the context of interpreting change and ascertaining connectivity among species in ecological systems. Analysis of these models support predictions that systems with strongly fluctuating community structure, but an otherwise stable long-term dynamic defined by a stationary attractor, indicate an invariant length scale irrespective of community structure at the time of analysis, and irrespective of the species analyzed. In contrast, if changes in the underlying dynamic are forcibly induced, the shift in dynamics is reflected by a change in the primary length scale. Thus, consideration of the magnitude of the CLS through time enables distinguishing between circumstances where there are temporal changes in community structure but not in the long-term dynamic, from that where changes in community structure reflect some kind of fundamental shift in dynamics. In this context, CLSs emerge as a diagnostic tool to identify phase shifts to alternative stable states

  10. Spontaneous transmission of chirality through multiple length scales.

    Science.gov (United States)

    Iski, Erin V; Tierney, Heather L; Jewell, April D; Sykes, E Charles H

    2011-06-20

    The hierarchical transfer of chirality in nature, from the nano-, to meso-, to macroscopic length scales, is very complex, and as of yet, not well understood. The advent of scanning probes has allowed chirality to be monitored at the single molecule or monolayer level and has opened up the possibility to track enantiospecific interactions and chiral self-assembly with molecular-scale detail. This paper describes the self-assembly of a simple, model molecule (naphtho[2,3-a]pyrene) that is achiral in the gas phase, but becomes chiral when adsorbed on a surface. This polyaromatic hydrocarbon forms a stable and reversibly ordered system on Cu(111) in which the transmission of chirality from single surface-bound molecules to complex 2D chiral architectures can be monitored as a function of molecular packing density and surface temperature. In addition to the point chirality of the surface-bound molecule, the unit cell of the molecular domains was also found to be chiral due to the incommensurate alignment of the molecular rows with respect to the underlying metal lattice. These molecular domains always aggregated in groups of three, all of the same chirality, but with different rotational orientations, forming homochiral "tri-lobe" ensembles. At a larger length scale, these tri-lobe ensembles associated with nearest-neighbor tri-lobe units of opposite chirality at lower packing densities before forming an extended array of homochiral tri-lobe ensembles at higher converges. This system displayed chirality at a variety of size scales from the molecular (≈1 nm) and domain (≈5 nm) to the tri-lobe ensemble (≈10 nm) and extended array (>25 nm) levels. The chirality of the tri-lobe ensembles dictated how the overall surface packing occurred and both homo- and heterochiral arrays could be reproducibly and reversibly formed and interchanged as a function of surface coverage. Finally, these chirally templated surfaces displayed remarkable enantiospecificity for

  11. Scaled Particle Theory and the Length-scales Involved in Hydrophobic Hydration of Aqueous Biomolecular Assemblies

    CERN Document Server

    Ashbaugh, H S; Ashbaugh, Henry S.; Pratt, Lawrence R.

    2003-01-01

    Hydrophobic hydration plays a crucial role in self-assembly processes over multiple-length scales, from the microscopic origins of inert gas solubility in water, to the mesoscopic organization of proteins and surfactant structures, to macroscopic phase separation. Many theoretical studies focus on the molecularly detailed interactions between oil and water, but the extrapolation of molecular-scale models to larger length scale hydration phenomena is sometimes not warranted. We revisit the scaled particle theory proposed thirty years ago by Stillinger, adopt a practical generalization, and consider the implications for hydrophobic hydration in light of our current understanding. The generalization is based upon identifying a molecular length, implicit in previous applications of scaled particle models, that provides an effective boundary radius for joining microscopic and macroscopic descriptions. We demonstrate that the generalized theory correctly reproduces many of the anomalous thermodynamic properties of ...

  12. Scaling characteristics of topographic depressions

    Science.gov (United States)

    Le, P. V.; Kumar, P.

    2013-12-01

    Topographic depressions, areas of no lateral surface flow, are ubiquitous characteristic of land surface that control many ecosystem and biogeochemical processes. Landscapes with high density of depressions increase the surface storage capacity, whereas lower depression density increase runoff, thus influencing soil moisture states, hydrologic connectivity and the climate--soil--vegetation interactions. With the widespread availability of high resolution LiDAR based digital elevation model (lDEM) data, it is now possible to identify and characterize the structure of the spatial distribution of topographic depressions for incorporation in ecohydrologic and biogeochemical studies. Here we use lDEM data to document the prevalence and patterns of topographic depressions across five different landscapes in the United States and quantitatively characterize the distribution of attributes, such as surface area, storage volume, and the distance to the nearest neighbor. Through the use of a depression identification algorithm, we show that these distribution attributes follow scaling laws indicative of a fractal structure in which a large fraction of land surface areas can consist of high number of topographic depressions, accounting for 4 to 200 mm of depression storage. This implies that the impacts of small-scale topographic depressions in the fractal landscapes on the redistribution of surface energy fluxes, evaporation, and hydrologic connectivity are quite significant.

  13. Minimum description length methods of medium-scale simultaneous inference

    CERN Document Server

    Bickel, David R

    2010-01-01

    Nonparametric statistical methods developed for analyzing data for high numbers of genes, SNPs, or other biological features tend to overfit data with smaller numbers of features such as proteins, metabolites, or, when expression is measured with conventional instruments, genes. For this medium-scale inference problem, the minimum description length (MDL) framework quantifies the amount of information in the data supporting a null or alternative hypothesis for each feature in terms of parametric model selection. Two new MDL techniques are proposed. First, using test statistics that are highly informative about the parameter of interest, the data are reduced to a single statistic per feature. This simplifying step is already implicit in conventional hypothesis testing and has been found effective in empirical Bayes applications to genomics data. Second, the codelength difference between the alternative and null hypotheses of any given feature can take advantage of information in the measurements from all other...

  14. Hybrid Supramolecular and Colloidal Hydrogels that Bridge Multiple Length Scales**

    Science.gov (United States)

    Janeček, Emma-Rose; McKee, Jason R; Tan, Cindy S Y; Nykänen, Antti; Kettunen, Marjo; Laine, Janne; Ikkala, Olli; Scherman, Oren A

    2015-01-01

    Hybrid nanocomposites were constructed based on colloidal nanofibrillar hydrogels with interpenetrating supramolecular hydrogels, displaying enhanced rheological yield strain and a synergistic improvement in storage modulus. The supramolecular hydrogel consists of naphthyl-functionalized hydroxyethyl cellulose and a cationic polystyrene derivative decorated with methylviologen moieties, physically cross-linked with cucurbit[8]uril macrocyclic hosts. Fast exchange kinetics within the supramolecular system are enabled by reversible cross-linking through the binding of the naphthyl and viologen guests. The colloidal hydrogel consists of nanofibrillated cellulose that combines a mechanically strong nanofiber skeleton with a lateral fibrillar diameter of a few nanometers. The two networks interact through hydroxyethyl cellulose adsorption to the nanofibrillated cellulose surfaces. This work shows methods to bridge the length scales of molecular and colloidal hybrid hydrogels, resulting in synergy between reinforcement and dynamics. PMID:25772264

  15. Density Functional Theory and Materials Modeling at Atomistic Length Scales

    Directory of Open Access Journals (Sweden)

    Swapan K. Ghosh

    2002-04-01

    Full Text Available Abstract: We discuss the basic concepts of density functional theory (DFT as applied to materials modeling in the microscopic, mesoscopic and macroscopic length scales. The picture that emerges is that of a single unified framework for the study of both quantum and classical systems. While for quantum DFT, the central equation is a one-particle Schrodinger-like Kohn-Sham equation, the classical DFT consists of Boltzmann type distributions, both corresponding to a system of noninteracting particles in the field of a density-dependent effective potential, the exact functional form of which is unknown. One therefore approximates the exchange-correlation potential for quantum systems and the excess free energy density functional or the direct correlation functions for classical systems. Illustrative applications of quantum DFT to microscopic modeling of molecular interaction and that of classical DFT to a mesoscopic modeling of soft condensed matter systems are highlighted.

  16. Natural length scales define the range of applicability of the Richards equation for capillary flows

    Science.gov (United States)

    Or, Dani; Lehmann, Peter; Assouline, Shmuel

    2015-09-01

    The rapid expansion of remotely sensed spatial information and enhanced computational capabilities fuel raising scientific and public expectations for reliable hydrologic predictions across time and spatial scales. Process-based hydrologic models often rely on the Richards equation (RE) formalism to represent unsaturated flow processes at multiple scales which raises the much debated question: does the underlying physics in the RE formulation apply at large scales of practical interest? The study analyses recent findings from different unsaturated flow processes (soil evaporation, internal redistribution, and capillary flow from point sources) revealing inherent characteristic length scales that delineate the spatial range of applicability of the RE. These length scales reflect the role of intrinsic porous medium properties that shape liquid phase continuity and interplay of forces that drive and resist unsaturated flow. The study revisits some of the key assumptions in the RE and their ramifications for numerical discretization. An intrinsic length scale for hydraulic continuity deduced from pore size distribution has been shown to control soil evaporation dynamics (i.e., stage 1 to stage 2 transition), to provide upper bounds for regional evaporative losses, and governs the dynamics of internal redistribution toward field capacity. For large-scale hydrologic applications, we show that the spatial extent of lateral flow interactions under most natural capillary gradients rarely exceed a few meters. The study provides a framework for guiding numerical and mathematical models for capillary flows across different scales considering the conditions for coexistence of stationarity, hydraulic continuity, and capillary gradients—essential ingredients for physically consistent application of the RE.

  17. Sperm length, sperm storage and mating system characteristics in bumblebees

    DEFF Research Database (Denmark)

    Baer, Boris; Schmid-Hempel, Paul; Høeg, Jens Thorvald;

    2003-01-01

    Multiple insemination induces sperm competition and may select for longer, faster moving sperm in species where sperm is short-lived and egg fertilization takes place almost immediately after ejaculation. Here we report the first detailed analysis of sperm length in social insects with long...

  18. Length scale of vortices and mode competition in quasi 2D shear flows

    International Nuclear Information System (INIS)

    Strictly 2D flows constitute a broad and useful class of Navier-Stokes solutions, but in practice they are quickly destroyed by 3D instability. A class of quasi two-dimensional (Q2D) flows can be defined in physical terms as flows whose approximate two-dimensionality is due to the presence of flat boundaries (bottom and/or top) so that vertical velocity component is negligible. However the vertical dependence of horizontal velocity is essential in that it provides most of the dissipation. This results in the Rayleigh friction term, -λΔΨ in the governing Q2D equation for stream function Ψ. Large scale atmospheric flows can be regarded as Q2D with λ being the inverse Ekman time scale. The Rayleigh, or external friction drastically changes both weakly and strongly nonlinear behaviour of shear flows. For the latter, it cuts off the inverse energy cascade at large scales, thus providing the characteristic length scale of instability generated vortical structures. This contribution presents results of numerical simulation of a Q2D shear flow at moderate Reynolds numbers, when inverse energy cascade leads to competition of vortical modes with different length scales. Results are compared with experimental data

  19. Physics on Smallest Scales - An Introduction to Minimal Length Phenomenology

    CERN Document Server

    Sprenger, Martin; Bleicher, Marcus

    2012-01-01

    Many modern theories which try to unite gravity with the Standard Model of particle physics, as e.g. string theory, propose two key modifications to the commonly known physical theories: i) the existence of additional space dimensions; ii) the existence of a minimal length distance or maximal resolution. While extra dimensions have received a wide coverage in publications over the last ten years (especially due to the prediction of micro black hole production at the LHC), the phenomenology of models with a minimal length is still less investigated. In a summer study project for bachelor students in 2010 we have explored some phenomenological implications of the potential existence of a minimal length. In this paper we review the idea and formalism of a quantum gravity induced minimal length in the generalised uncertainty principle framework as well as in the coherent state approach to non-commutative geometry. These approaches are effective models which can make model-independent predictions for experiments a...

  20. Proton conduction in exchange membranes across multiple length scales.

    Science.gov (United States)

    Jorn, Ryan; Savage, John; Voth, Gregory A

    2012-11-20

    Concerns over global climate change associated with fossil-fuel consumption continue to drive the development of electrochemical alternatives for energy technology. Proton exchange fuel cells are a particularly promising technology for stationary power generation, mobile electronics, and hybrid engines in automobiles. For these devices to work efficiently, direct electrical contacts between the anode and cathode must be avoided; hence, the separator material must be electronically insulating but highly proton conductive. As a result, researchers have examined a variety of polymer electrolyte materials for use as membranes in these systems. In the optimization of the membrane, researchers are seeking high proton conductivity, low electronic conduction, and mechanical stability with the inclusion of water in the polymer matrix. A considerable number of potential polymer backbone and side chain combinations have been synthesized to meet these requirements, and computational studies can assist in the challenge of designing the next generation of technologically relevant membranes. Such studies can also be integrated in a feedback loop with experiment to improve fuel cell performance. However, to accurately simulate the currently favored class of membranes, perfluorosulfonic acid containing moieties, several difficulties must be addressed including a proper treatment of the proton-hopping mechanism through the membrane and the formation of nanophase-separated water networks. We discuss our recent efforts to address these difficulties using methods that push the limits of computer simulation and expand on previous theoretical developments. We describe recent advances in the multistate empirical valence bond (MS-EVB) method that can probe proton diffusion at the nanometer-length scale and accurately model the so-called Grotthuss shuttling mechanism for proton diffusion in water. Using both classical molecular dynamics and coarse-grained descriptions that replace atomistic

  1. Inlet Turbulence and Length Scale Measurements in a Large Scale Transonic Turbine Cascade

    Science.gov (United States)

    Thurman, Douglas; Flegel, Ashlie; Giel, Paul

    2014-01-01

    Constant temperature hotwire anemometry data were acquired to determine the inlet turbulence conditions of a transonic turbine blade linear cascade. Flow conditions and angles were investigated that corresponded to the take-off and cruise conditions of the Variable Speed Power Turbine (VSPT) project and to an Energy Efficient Engine (EEE) scaled rotor blade tip section. Mean and turbulent flowfield measurements including intensity, length scale, turbulence decay, and power spectra were determined for high and low turbulence intensity flows at various Reynolds numbers and spanwise locations. The experimental data will be useful for establishing the inlet boundary conditions needed to validate turbulence models in CFD codes.

  2. Recognition and assembly at multiple length-scales

    Science.gov (United States)

    Olmsted, Brian Keith

    contours to study how symmetry and packing originates at the micron length-scale. Although much is known about assembly at the molecular level for symmetry and packing, the assembly of anisotropic particles at longer length scales, which involve different interactive forces, has not been studied. This work concludes by performing preliminary work in elucidating the general behavior towards symmetry and packing in two-dimensions of micron-sized particles by using gravitational gradients and dielectrophoresis.

  3. Physics on smallest scales. An introduction to minimal length phenomenology

    Energy Technology Data Exchange (ETDEWEB)

    Sprenger, Martin [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Goethe Univ., Frankfurt am Main (Germany). Inst. for Theoretical Physics and Frankfurt Institute for Advanced Studies; Nicolini, Piero; Bleicher, Marcus [Goethe Univ., Frankfurt am Main (Germany). Inst. for Theoretical Physics and Frankfurt Institute for Advanced Studies

    2012-02-15

    Many modern theories which try to unite gravity with the Standard Model of particle physics, as e.g. string theory, propose two key modifications to the commonly known physical theories: - the existence of additional space dimensions - the existence of a minimal length distance or maximal resolution. While extra dimensions have received a wide coverage in publications over the last ten years (especially due to the prediction of micro black hole production at the LHC), the phenomenology of models with a minimal length is still less investigated. In a summer study project for bachelor students in 2010 we have explored some phenomenological implications of the potential existence of a minimal length. In this paper we review the idea and formalism of a quantum gravity induced minimal length in the generalised uncertainty principle framework as well as in the coherent state approach to non- commutative geometry. These approaches are effective models which can make model-independent predictions for experiments and are ideally suited for phenomenological studies. Pedagogical examples are provided to grasp the effects of a quantum gravity induced minimal length. (orig.)

  4. Scaling limits for shortest path lengths along the edges of stationary tessellations - Supplementary material

    CERN Document Server

    Voss, Florian; Schmidt, Volker

    2009-01-01

    We consider spatial stochastic models, which can be applied e.g. to telecommunication networks with two hierarchy levels. In particular, we consider two Cox processes concentrated on the edge set of a random tessellation, where the points can describe the locations of low-level and high-level network components, respectively, and the edge set the underlying infrastructure of the network, like road systems, railways, etc. Furthermore, each low-level component is marked with the shortest path along the edge set to the nearest high-level component. We investigate the typical shortest path length of the resulting marked point process, which is an important characteristic e.g. in performance analysis and planning of telecommunication networks. In particular, we show that its distribution converges to simple parametric limit distributions if a certain scaling factor converges to zero and infinity, respectively. This can be used to approximate the density of the typical shortest path length by analytical formulae.

  5. Length Scales of the Neutral Wind Profile over Homogeneous Terrain

    DEFF Research Database (Denmark)

    Pena Diaz, Alfredo; Gryning, Sven-Erik; Mann, Jakob;

    2010-01-01

    The wind speed profile for the neutral boundary layer is derived for a number of mixing-length parameterizations, which account for the height of the boundary layer. The wind speed profiles show good agreement with the reanalysis of the Leipzig wind profile (950 m high) and with combined cup–soni...

  6. Electroweak symmetries from the topology of deformed spacetime with minimal length scale

    CERN Document Server

    Gresnigt, Niels G

    2015-01-01

    Lie-type deformations provide a systematic way of generalising the symmetries of modern physics. Deforming the isometry group of Minkowski spacetime through the introduction of a minimal length scale $\\ell$ leads to anti de Sitter spacetime with isometry group $SO(2,3)$. Quantum spacetime on scales of the order $\\ell$ therefore carries negative curvature. Considering extended particles of characteristic size $\\ell$ carrying topological information and requiring that their topological properties be compatible with those of the underlying spacetime, we show that electroweak symmetries emerge from the maximal compact subgroup of the anti de Sitter isometry group in a way that is consistent with no-go theorems. It is speculated that additional deformation outside the Lie-algebraic framework, such as $q$-deformations, could likewise provide an explanation of the origin of the strong force.

  7. Analysis of Average Shortest-Path Length of Scale-Free Network

    Directory of Open Access Journals (Sweden)

    Guoyong Mao

    2013-01-01

    Full Text Available Computing the average shortest-path length of a large scale-free network needs much memory space and computation time. Hence, parallel computing must be applied. In order to solve the load-balancing problem for coarse-grained parallelization, the relationship between the computing time of a single-source shortest-path length of node and the features of node is studied. We present a dynamic programming model using the average outdegree of neighboring nodes of different levels as the variable and the minimum time difference as the target. The coefficients are determined on time measurable networks. A native array and multimap representation of network are presented to reduce the memory consumption of the network such that large networks can still be loaded into the memory of each computing core. The simplified load-balancing model is applied on a network of tens of millions of nodes. Our experiment shows that this model can solve the load-imbalance problem of large scale-free network very well. Also, the characteristic of this model can meet the requirements of networks with ever-increasing complexity and scale.

  8. Reionization: Characteristic Scales, Topology And Observability

    Energy Technology Data Exchange (ETDEWEB)

    Iliev, Ilian T.; /Canadian Inst. Theor. Astrophys. /Zurich U.; Shapiro, Paul R.; /Texas U., Astron. Dept.; Mellema, Garrelt; /Stockholm Observ.; Pen, Ue-Li; McDonald, Patrick; /Canadian Inst. Theor. Astrophys.; Alvarez, Marcelo A.; /KIPAC, Menlo Park

    2007-11-02

    Recently the numerical simulations of the process of reionization of the universe at z > 6 have made a qualitative leap forward, reaching sufficient sizes and dynamic range to determine the characteristic scales of this process. This allowed making the first realistic predictions for a variety of observational signatures. We discuss recent results from large-scale radiative transfer and structure formation simulations on the observability of high-redshift Ly-{alpha} sources. We also briefly discuss the dependence of the characteristic scales and topology of the ionized and neutral patches on the reionization parameters.

  9. Length scales in glass-forming liquids and related systems: a review

    Science.gov (United States)

    Karmakar, Smarajit; Dasgupta, Chandan; Sastry, Srikanth

    2016-01-01

    The central problem in the study of glass-forming liquids and other glassy systems is the understanding of the complex structural relaxation and rapid growth of relaxation times seen on approaching the glass transition. A central conceptual question is whether one can identify one or more growing length scale(s) associated with this behavior. Given the diversity of molecular glass-formers and a vast body of experimental, computational and theoretical work addressing glassy behavior, a number of ideas and observations pertaining to growing length scales have been presented over the past few decades, but there is as yet no consensus view on this question. In this review, we will summarize the salient results and the state of our understanding of length scales associated with dynamical slow down. After a review of slow dynamics and the glass transition, pertinent theories of the glass transition will be summarized and a survey of ideas relating to length scales in glassy systems will be presented. A number of studies have focused on the emergence of preferred packing arrangements and discussed their role in glassy dynamics. More recently, a central object of attention has been the study of spatially correlated, heterogeneous dynamics and the associated length scale, studied in computer simulations and theoretical analysis such as inhomogeneous mode coupling theory. A number of static length scales have been proposed and studied recently, such as the mosaic length scale discussed in the random first-order transition theory and the related point-to-set correlation length. We will discuss these, elaborating on key results, along with a critical appraisal of the state of the art. Finally we will discuss length scales in driven soft matter, granular fluids and amorphous solids, and give a brief description of length scales in aging systems. Possible relations of these length scales with those in glass-forming liquids will be discussed.

  10. Minimum Pay Scale and Career Length in the NBA

    OpenAIRE

    Johnny Ducking; Peter A. Groothuis; James Richard Hill

    2012-01-01

    We use data from the National Basketball Association (NBA) to analyze the impact of minimum salaries on an employee’s career length. The NBA has a salary structure in which the minimum salary a player can receive increases with the player’s years of experience. Salary schedules similar to the NBA’s exist in public education, federal government agencies, the Episcopalian church, and unionized industries. Even though the magnitude of the salaries in the NBA differs from other industries, this s...

  11. SQUID magnetometry from nanometer to centimeter length scales

    International Nuclear Information System (INIS)

    The development of Superconducting QUantum Interference Device (SQUID)-based magnetometer for two applications, in vivo prepolarized, ultra-low field MRI of humans and dispersive readout of SQUIDs for micro- and nano-scale magnetometery, are the focus of this thesis.

  12. SQUID magnetometry from nanometer to centimeter length scales

    Energy Technology Data Exchange (ETDEWEB)

    Hatridge, Michael J.

    2010-06-28

    The development of Superconducting QUantum Interference Device (SQUID)-based magnetometer for two applications, in vivo prepolarized, ultra-low field MRI of humans and dispersive readout of SQUIDs for micro- and nano-scale magnetometery, are the focus of this thesis.

  13. SQUID magnetometry from nanometer to centimeter length scales

    Energy Technology Data Exchange (ETDEWEB)

    Hatridge, Michael J. [Univ. of California, Berkeley, CA (United States)

    2010-06-01

    The development of Superconducting QUantum Interference Device (SQUID)-based magnetometer for two applications, in vivo prepolarized, ultra-low field MRI of humans and dispersive readout of SQUIDs for micro- and nano-scale magnetometery, are the focus of this thesis.

  14. Determination of Longitudinal Electron Bunch Lengths on Picosecond Time Scales

    CERN Document Server

    Martínez, C; Calviño, F

    1999-01-01

    At CERN (European Laboratory for Particle Physics) the CLIC (Compact Linear Collider) study is pursuing the design of an electron-positron high-energy linear collider using an innovative concept for the RF (Radio Frequency) power production, the socalled two-beam acceleration scheme. In order to keep the length of the collider in a reasonable range while being able of accelerating electrons and positrons up to 5 TeV, the normal-conducting accelerating structures should operate at very high frequency (in this case 30 GHz). The RF power necessary to feed the accelerating cavities is provided by a second electron beam, the drive beam, running parallel to the main beam. The CLIC Test Facility (CTF) was build with the main aim of studying and demonstrating the feasibility of the two beam acceleration scheme and technology. It is composed of two beams, the drive beam that will generate the 30 GHz RF power and the main beam which will be accelerated by this power. In order to have a good efficiency for the power gen...

  15. Non-perturbative gravity at different length scales

    Energy Technology Data Exchange (ETDEWEB)

    Folkerts, Sarah

    2013-12-18

    In this thesis, we investigate different aspects of gravity as an effective field theory. Building on the arguments of self-completeness of Einstein gravity, we argue that any sensible theory, which does not propagate negative-norm states and reduces to General Relativity in the low energy limit is self-complete. Due to black hole formation in high energy scattering experiments, distances smaller than the Planck scale are shielded from any accessibility. Degrees of freedom with masses larger than the Planck mass are mapped to large classical black holes which are described by the already existing infrared theory. Since high energy (UV) modifications of gravity which are ghost-free can only produce stronger gravitational interactions than Einstein gravity, the black hole shielding is even more efficient in such theories. In this light, we argue that conventional attempts of a Wilsonian UV completion are severely constrained. Furthermore, we investigate the quantum picture for black holes which emerges in the low energy description put forward by Dvali and Gomez in which black holes are described as Bose-Einstein condensates of many weakly coupled gravitons. Specifically, we investigate a non-relativistic toy model which mimics certain aspects of the graviton condensate picture. This toy model describes the collapse of a condensate of attractive bosons which emits particles due to incoherent scattering. We show that it is possible that the evolution of the condensate follows the critical point which is accompanied by the appearance of a light mode. Another aspect of gravitational interactions concerns the question whether quantum gravity breaks global symmetries. Arguments relying on the no hair theorem and wormhole solutions suggest that global symmetries can be violated. In this thesis, we parametrize such effects in terms of an effective field theory description of three-form fields. We investigate the possible implications for the axion solution of the strong CP

  16. Non-perturbative gravity at different length scales

    International Nuclear Information System (INIS)

    In this thesis, we investigate different aspects of gravity as an effective field theory. Building on the arguments of self-completeness of Einstein gravity, we argue that any sensible theory, which does not propagate negative-norm states and reduces to General Relativity in the low energy limit is self-complete. Due to black hole formation in high energy scattering experiments, distances smaller than the Planck scale are shielded from any accessibility. Degrees of freedom with masses larger than the Planck mass are mapped to large classical black holes which are described by the already existing infrared theory. Since high energy (UV) modifications of gravity which are ghost-free can only produce stronger gravitational interactions than Einstein gravity, the black hole shielding is even more efficient in such theories. In this light, we argue that conventional attempts of a Wilsonian UV completion are severely constrained. Furthermore, we investigate the quantum picture for black holes which emerges in the low energy description put forward by Dvali and Gomez in which black holes are described as Bose-Einstein condensates of many weakly coupled gravitons. Specifically, we investigate a non-relativistic toy model which mimics certain aspects of the graviton condensate picture. This toy model describes the collapse of a condensate of attractive bosons which emits particles due to incoherent scattering. We show that it is possible that the evolution of the condensate follows the critical point which is accompanied by the appearance of a light mode. Another aspect of gravitational interactions concerns the question whether quantum gravity breaks global symmetries. Arguments relying on the no hair theorem and wormhole solutions suggest that global symmetries can be violated. In this thesis, we parametrize such effects in terms of an effective field theory description of three-form fields. We investigate the possible implications for the axion solution of the strong CP

  17. Plasma scale-length effects on electron energy spectra in high-irradiance laser plasmas

    Science.gov (United States)

    Culfa, O.; Tallents, G. J.; Rossall, A. K.; Wagenaars, E.; Ridgers, C. P.; Murphy, C. D.; Dance, R. J.; Gray, R. J.; McKenna, P.; Brown, C. D. R.; James, S. F.; Hoarty, D. J.; Booth, N.; Robinson, A. P. L.; Lancaster, K. L.; Pikuz, S. A.; Faenov, A. Ya.; Kampfer, T.; Schulze, K. S.; Uschmann, I.; Woolsey, N. C.

    2016-04-01

    An analysis of an electron spectrometer used to characterize fast electrons generated by ultraintense (1020W cm-2 ) laser interaction with a preformed plasma of scale length measured by shadowgraphy is presented. The effects of fringing magnetic fields on the electron spectral measurements and the accuracy of density scale-length measurements are evaluated. 2D EPOCH PIC code simulations are found to be in agreement with measurements of the electron energy spectra showing that laser filamentation in plasma preformed by a prepulse is important with longer plasma scale lengths (>8 μ m ).

  18. Femtosecond structural dynamics on the atomic length scale

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Dongfang

    2014-03-15

    This thesis reports on the development and application of two different but complementary ultrafast electron diffraction setups built at the Max Planck Research Department for Structural Dynamics. One is an ultra-compact femtosecond electron diffraction (FED) setup (Egun300), which is currently operational (with a maximum electron energy of 150 keV) and provides ultrashort (∝300 fs) and bright (∝10 e/μm{sup 2}) electron bunches. The other one, named as Relativistic Electron Gun for Atomic Exploration (REGAE) is a radio frequency driven 2 to 5 MeV FED setup built in collaboration with different groups from DESY. REGAE was developed as a facility that will provide high quality diffraction with sufficient coherence to even address structural protein dynamics and with electron pulses as short as 20 fs (FWHM). As one of the first students in Prof. R.J. Dwayne Miller's group, I led the femtosecond (fs) laser sub-group at REGAE being responsible for the construction of different key optical elements required to drive both of aforementioned FED systems. A third harmonic generation (THG) and a nonlinear optical parametric amplifier (NOPA) have been used for the photo-generation of ultrashort electron bursts as well as sample laser excitation. Different diagnostic tools have been constructed to monitor the performance of the fs optical system. A fast autocorrelator was developed to provide on the fly pulse duration correction. A transient-grating frequency-resolved optical gating (TG-FROG) was built to obtain detail information about the characteristics of fs optical pulse, i.e. phase and amplitude of its spectral components. In addition to these optical setups, I developed a fs optical pump-probe system, which supports broadband probe pulses. This setup was successfully applied to investigate the semiconductor-to-metal photoinduced phase transition in VO{sub 2} and the ultrafast photo-reduction mechanism of graphene oxide. In regard to FED setups, I have been

  19. Femtosecond structural dynamics on the atomic length scale

    International Nuclear Information System (INIS)

    This thesis reports on the development and application of two different but complementary ultrafast electron diffraction setups built at the Max Planck Research Department for Structural Dynamics. One is an ultra-compact femtosecond electron diffraction (FED) setup (Egun300), which is currently operational (with a maximum electron energy of 150 keV) and provides ultrashort (∝300 fs) and bright (∝10 e/μm2) electron bunches. The other one, named as Relativistic Electron Gun for Atomic Exploration (REGAE) is a radio frequency driven 2 to 5 MeV FED setup built in collaboration with different groups from DESY. REGAE was developed as a facility that will provide high quality diffraction with sufficient coherence to even address structural protein dynamics and with electron pulses as short as 20 fs (FWHM). As one of the first students in Prof. R.J. Dwayne Miller's group, I led the femtosecond (fs) laser sub-group at REGAE being responsible for the construction of different key optical elements required to drive both of aforementioned FED systems. A third harmonic generation (THG) and a nonlinear optical parametric amplifier (NOPA) have been used for the photo-generation of ultrashort electron bursts as well as sample laser excitation. Different diagnostic tools have been constructed to monitor the performance of the fs optical system. A fast autocorrelator was developed to provide on the fly pulse duration correction. A transient-grating frequency-resolved optical gating (TG-FROG) was built to obtain detail information about the characteristics of fs optical pulse, i.e. phase and amplitude of its spectral components. In addition to these optical setups, I developed a fs optical pump-probe system, which supports broadband probe pulses. This setup was successfully applied to investigate the semiconductor-to-metal photoinduced phase transition in VO2 and the ultrafast photo-reduction mechanism of graphene oxide. In regard to FED setups, I have been deeply involved in

  20. Interactions between a fractal tree-like object and hydrodynamic turbulence: flow structure and characteristic mixing length

    Science.gov (United States)

    Meneveau, C. V.; Bai, K.; Katz, J.

    2011-12-01

    The vegetation canopy has a significant impact on various physical and biological processes such as forest microclimate, rainfall evaporation distribution and climate change. Most scaled laboratory experimental studies have used canopy element models that consist of rigid vertical strips or cylindrical rods that can be typically represented through only one or a few characteristic length scales, for example the diameter and height for cylindrical rods. However, most natural canopies and vegetation are highly multi-scale with branches and sub-branches, covering a wide range of length scales. Fractals provide a convenient idealization of multi-scale objects, since their multi-scale properties can be described in simple ways (Mandelbrot 1982). While fractal aspects of turbulence have been studied in several works in the past decades, research on turbulence generated by fractal objects started more recently. We present an experimental study of boundary layer flow over fractal tree-like objects. Detailed Particle-Image-Velocimetry (PIV) measurements are carried out in the near-wake of a fractal-like tree. The tree is a pre-fractal with five generations, with three branches and a scale reduction factor 1/2 at each generation. Its similarity fractal dimension (Mandelbrot 1982) is D ~ 1.58. Detailed mean velocity and turbulence stress profiles are documented, as well as their downstream development. We then turn attention to the turbulence mixing properties of the flow, specifically to the question whether a mixing length-scale can be identified in this flow, and if so, how it relates to the geometric length-scales in the pre-fractal object. Scatter plots of mean velocity gradient (shear) and Reynolds shear stress exhibit good linear relation at all locations in the flow. Therefore, in the transverse direction of the wake evolution, the Boussinesq eddy viscosity concept is appropriate to describe the mixing. We find that the measured mixing length increases with increasing

  1. Supramolecular Routes to Hierarchical Structures : Comb-Coil Diblock Copolymers Organized with Two Length Scales

    NARCIS (Netherlands)

    Ruokolainen, J.; Saariaho, M.; Ikkala, O.; Brinke, G. ten; Thomas, E.L.; Torkkeli, M.; Serimaa, R.

    1999-01-01

    We show that polymeric materials characterized by two length scales are obtained if diblock copolymers are mixed with amphiphilic selective solvents, leading to self-organization which combines the “block copolymer length scale” with a much shorter “nanoscale”. In this work, the amphiphilic compound

  2. Morphology Characterization of PP/Clay Nanocomposites Across the Length Scales of the Structural Architecture

    NARCIS (Netherlands)

    Szazdi, Laszlo; Abranyi, Agnes; Pukansky Jr, Bela; Vancso, G. Julius; Pukanszky, Bela

    2006-01-01

    The structure and rheological properties of a large number of layered silicate poly(propylene) nanocomposites were studied with widely varying compositions. Morphology characterization at different length scales was achieved by SEM, TEM, and XRD. Rheological measurements supplied additional informat

  3. Interplay between multiple length and time scales in complex chemical systems

    OpenAIRE

    Bagchi, Biman; Chakravarty, Charusita

    2010-01-01

    Processes in complex chemical systems, such as macromolecules, electrolytes, interfaces, micelles and enzymes, can span several orders of magnitude in length and time scales. The length and time scales of processes occurring over this broad time and space window are frequently coupled to give rise to the control necessary to ensure specificity and the uniqueness of the chemical phenomena. A combination of experimental, theoretical and computational techniques that can address a multiplicity o...

  4. Kelvin Absolute Temperature Scale Identified as Length Scale and Related to de Broglie Thermal Wavelength

    Science.gov (United States)

    Sohrab, Siavash

    Thermodynamic equilibrium between matter and radiation leads to de Broglie wavelength λdβ = h /mβvrβ and frequency νdβ = k /mβvrβ of matter waves and stochastic definitions of Planck h =hk =mk c and Boltzmann k =kk =mk c constants, λrkνrk = c , that respectively relate to spatial (λ) and temporal (ν) aspects of vacuum fluctuations. Photon massmk =√{ hk /c3 } , amu =√{ hkc } = 1 /No , and universal gas constant Ro =No k =√{ k / hc } result in internal Uk = Nhνrk = Nmkc2 = 3 Nmkvmpk2 = 3 NkT and potential pV = uN\\vcirc / 3 = N\\ucirc / 3 = NkT energy of photon gas in Casimir vacuum such that H = TS = 4 NkT . Therefore, Kelvin absolute thermodynamic temperature scale [degree K] is identified as length scale [meter] and related to most probable wavelength and de Broglie thermal wavelength as Tβ =λmpβ =λdβ / 3 . Parallel to Wien displacement law obtained from Planck distribution, the displacement law λwS T =c2 /√{ 3} is obtained from Maxwell -Boltzmann distribution of speed of ``photon clusters''. The propagation speeds of sound waves in ideal gas versus light waves in photon gas are described in terms of vrβ in harmony with perceptions of Huygens. Newton formula for speed of long waves in canals √{ p / ρ } is modified to √{ gh } =√{ γp / ρ } in accordance with adiabatic theory of Laplace.

  5. Virtual Testing of Large Composite Structures: A Multiple Length/Time-Scale Framework

    Science.gov (United States)

    Gigliotti, Luigi; Pinho, Silvestre T.

    2015-12-01

    This paper illustrates a multiple length/time-scale framework for the virtual testing of large composite structures. Such framework hinges upon a Mesh Superposition Technique (MST) for the coupling between areas of the structure modelled at different length-scales and upon an efficient solid-to-shell numerical homogenization which exploits the internal symmetries of Unit Cells (UCs). Using this framework, it is possible to minimize the areas of the structure modelled at the lowest- (and computationally demanding) scales and the computational cost required to calculate the homogenised to be used in the higher-scales subdomains of multiscale FE models, as well as to simulate the mechanical response of different parts of the structure using different solvers, depending on where they are expected to provide the most computationally efficient solution. The relevance and key-aspects of the multiple length/time-scale framework are demonstrated through the analysis of a real-sized aeronautical composite component.

  6. Eringen's small length scale coefficient for buckling of nonlocal Timoshenko beam based on microstructured beam model

    Science.gov (United States)

    Zhang, Z.; Challamel, N.; Wang, C. M.

    2013-09-01

    This paper presents the determination of Eringen's small length scale coefficient e0 for buckling of nonlocal Timoshenko beam from a microstructured beam model. The microstructured beam model is composed of discrete rigid elements (of equal length), which are connected by rotational and shear springs that model the bending and shearing behaviors in a beam. The exact solution of e0 is given for nonlocal Timoshenko beam with small length scale term appearing in the normal stress-strain relation only. It is shown that e0 approaches 1/√12 ≈0.289 which coincides with the one calibrated for nonlocal Euler beams.

  7. Variability of interconnected wind plants: correlation length and its dependence on variability time scale

    Science.gov (United States)

    St. Martin, Clara M.; Lundquist, Julie K.; Handschy, Mark A.

    2015-04-01

    The variability in wind-generated electricity complicates the integration of this electricity into the electrical grid. This challenge steepens as the percentage of renewably-generated electricity on the grid grows, but variability can be reduced by exploiting geographic diversity: correlations between wind farms decrease as the separation between wind farms increases. But how far is far enough to reduce variability? Grid management requires balancing production on various timescales, and so consideration of correlations reflective of those timescales can guide the appropriate spatial scales of geographic diversity grid integration. To answer ‘how far is far enough,’ we investigate the universal behavior of geographic diversity by exploring wind-speed correlations using three extensive datasets spanning continents, durations and time resolution. First, one year of five-minute wind power generation data from 29 wind farms span 1270 km across Southeastern Australia (Australian Energy Market Operator). Second, 45 years of hourly 10 m wind-speeds from 117 stations span 5000 km across Canada (National Climate Data Archive of Environment Canada). Finally, four years of five-minute wind-speeds from 14 meteorological towers span 350 km of the Northwestern US (Bonneville Power Administration). After removing diurnal cycles and seasonal trends from all datasets, we investigate dependence of correlation length on time scale by digitally high-pass filtering the data on 0.25-2000 h timescales and calculating correlations between sites for each high-pass filter cut-off. Correlations fall to zero with increasing station separation distance, but the characteristic correlation length varies with the high-pass filter applied: the higher the cut-off frequency, the smaller the station separation required to achieve de-correlation. Remarkable similarities between these three datasets reveal behavior that, if universal, could be particularly useful for grid management. For high

  8. Does Scale Length Matter? A Comparison of Nine- versus Five-Point Rating Scales for the Mini-CEX

    Science.gov (United States)

    Cook, David A.; Beckman, Thomas J.

    2009-01-01

    Educators must often decide how many points to use in a rating scale. No studies have compared interrater reliability for different-length scales, and few have evaluated accuracy. This study sought to evaluate the interrater reliability and accuracy of mini-clinical evaluation exercise (mini-CEX) scores, comparing the traditional mini-CEX…

  9. Spatial confinement-induced switchover in microstructure evolution during severe plastic deformation at micrometer length scales

    International Nuclear Information System (INIS)

    Severe plastic deformation in micrometer scale sample volumes is investigated by performing large strain machining inside a scanning electron microscope. Digital image correlation of in situ secondary electron images of the deformation zone is used to measure the mechanics of deformation. The effect of length scales on microstructure evolution is characterized using orientation imaging microscopy/electron backscattered diffraction analysis of the deformation zone. A geometrically necessary switchover in microstructure evolution mechanisms in small length scales is identified and attributed to a coupled effect of geometric confinement and high strain gradients. A phenomenological model capturing the switchover is proposed. It is shown that contrary to conventional perception, a high crystallographic curvature caused by strain gradients impedes grain refinement in small length scales, resulting in an anomalous suppression of grain refinement and fragmentation

  10. The impact of tailored defects on length scales and current conduction in high-Tc superconductors

    International Nuclear Information System (INIS)

    This article surveys the formation and effects of ''tailored'' defects, having controlled numbers and several different morphologies, in high temperature superconductors. Defects can affect the equilibrium properties, such as the superconducting length scales ξ (the coherence length) and λ (the London penetration depth). Very importantly, defects provide vortex pinning that supports the conduction of a macroscopic current density. The article introduces these topics and illustrates them with specific examples. (orig.)

  11. Cable dynamics applied to long-length scale mechanics of DNA

    CERN Document Server

    Goyal, S; Perkins, N C; Meyhofer, E; Goyal, Sachin; Lillian, Todd; Perkins, Noel C.; Meyhofer, Edgar

    2007-01-01

    This paper introduces the use of cable dynamics models as a means to explore the mechanics of DNA on long-length scales. It is on these length scales that DNA forms twisted and curved three-dimensional shapes known as supercoils and loops. These long-length scale DNA structures have a pronounced influence on the functions of this molecule within the cell including the packing of DNA in the cell nucleus, transcription, replication and gene repair. We provide a short background to the mechanics of DNA and suggest the logical connection to the mechanics of a low tension cable. A computational model is then summarized and example results are presented for DNA supercoiling and looping.

  12. Critical length scales and strain localization govern the mechanical performance of multi-layer graphene assemblies

    Science.gov (United States)

    Xia, Wenjie; Ruiz, Luis; Pugno, Nicola M.; Keten, Sinan

    2016-03-01

    Multi-layer graphene assemblies (MLGs) or fibers with a staggered architecture exhibit high toughness and failure strain that surpass those of the constituent single sheets. However, how the architectural parameters such as the sheet overlap length affect these mechanical properties remains unknown due in part to the limitations of mechanical continuum models. By exploring the mechanics of MLG assemblies under tensile deformation using our established coarse-grained molecular modeling framework, we have identified three different critical interlayer overlap lengths controlling the strength, plastic stress, and toughness of MLGs, respectively. The shortest critical length scale Lsc governs the strength of the assembly as predicted by the shear-lag model. The intermediate critical length Lpc is associated with a dynamic frictional process that governs the strain localization propensity of the assembly, and hence the failure strain. The largest critical length scale LTc corresponds to the overlap length necessary to achieve 90% of the maximum theoretical toughness of the material. Our analyses provide the general guidelines for tuning the constitutive properties and toughness of multilayer 2D nanomaterials using elasticity, interlayer adhesion energy and geometry as molecular design parameters.Multi-layer graphene assemblies (MLGs) or fibers with a staggered architecture exhibit high toughness and failure strain that surpass those of the constituent single sheets. However, how the architectural parameters such as the sheet overlap length affect these mechanical properties remains unknown due in part to the limitations of mechanical continuum models. By exploring the mechanics of MLG assemblies under tensile deformation using our established coarse-grained molecular modeling framework, we have identified three different critical interlayer overlap lengths controlling the strength, plastic stress, and toughness of MLGs, respectively. The shortest critical length scale

  13. Micro-to-macro: astrodynamics at extremes of lengths-scale

    OpenAIRE

    McInnes, C. R.; Ceriotti, M.; Colombo, C.; Sanchez Cuartielles, J.P.; Bewick, R; Heiligers, J.; Lucking, C

    2011-01-01

    This paper investigates astrodynamics at extremes of length-scale, ranging from swarms of future `smart dust' devices to the capture and utilisation of small near Earth asteroids. At the smallest length-scales families of orbits are found which balance the energy gain from solar radiation pressure with energy dissipation due to air drag. This results in long orbit lifetimes for high area-to-mass ratio `smart dust' devices. High area-to-mass hybrid spacecraft, using both solar sail and electri...

  14. Bounds on fifth forces at the sub-Å length scale

    Science.gov (United States)

    Salumbides, E. J.; Ubachs, W.; Korobov, V. I.

    2014-06-01

    Constraints on a possible fifth-force interaction between hadrons are derived based on an analysis of results from laser precision frequency measurements of antiprotonic helium atoms, both pHe+ and pHe+ species, and from experiments on resonant formation rates of ddμ+-ions in muon-catalyzed fusion processes. A comparison is made between accurate experimental data and first-principles theoretical descriptions of the exotic systems within a quantum electrodynamical framework. The agreement between theory and experiment sets general limits on a possible additional hadron-hadron interaction, written in the form of a Yukawa potential V5(r)=α5exp(-r/λ)/r, with λ representing the characteristic length scale associated with the mass of a hypothetical force-carrying particle via λ=ℏ/(m5c). The laser spectroscopic data of antiprotonic helium set a constraint of α5/αEM<10-8 for λ<1 Å, while the binding energy of the muonic molecular deuterium ion delivers a constraint of α5/αEM∼10-5 for λ<0.05 Å, where αEM represents the strength of the electromagnetic interaction or the fine structure constant.

  15. Bounds on fifth forces at the sub-Angstrom length scale

    CERN Document Server

    Salumbides, E J; Korobov, V I

    2013-01-01

    Constraints on a possible fifth-force interaction between hadrons are derived based on an analysis of results from laser precision frequency measurements of antiprotonic helium atoms, both $\\bar{p}\\,^{4}$He$^{+}$ and $\\bar{p}\\,^{3}$He$^{+}$ species, and from experiments on resonant formation rates of $dd\\mu$-ions in muon-catalyzed fusion processes. A comparison is made between accurate experimental data and first-principles theoretical descriptions of the exotic systems within a quantum electrodynamical framework. The agreement between theory and experiment sets limits on a possible additional hadron-hadron interaction written in the form of a Yukawa potential $V_5(r)=\\alpha_5 \\exp(-r/\\lambda)/r$, with $\\lambda$ representing the characteristic length scale associated with the mass of a hypothetical force-carrying particle via $\\lambda=\\hbar/(m_5c)$. The laser spectroscopic data of antiprotonic helium set a constraint of $\\alpha_5/\\alpha_{EM} < 10^{-8}$ for $\\lambda < 1$ \\AA, while the binding energy of ...

  16. Interplay between multiple length and time scales in complex chemical systems

    Indian Academy of Sciences (India)

    Biman Bagchi; Charusita Chakravarty

    2010-07-01

    Processes in complex chemical systems, such as macromolecules, electrolytes, interfaces, micelles and enzymes, can span several orders of magnitude in length and time scales. The length and time scales of processes occurring over this broad time and space window are frequently coupled to give rise to the control necessary to ensure specificity and the uniqueness of the chemical phenomena. A combination of experimental, theoretical and computational techniques that can address a multiplicity of length and time scales is required in order to understand and predict structure and dynamics in such complex systems. This review highlights recent experimental developments that allow one to probe structure and dynamics at increasingly smaller length and time scales. The key theoretical approaches and computational strategies for integrating information across time-scales are discussed. The application of these ideas to understand phenomena in various areas, ranging from materials science to biology, is illustrated in the context of current developments in the areas of liquids and solvation, protein folding and aggregation and phase transitions, nucleation and self-assembly.

  17. Fracture length scales in human cortical bone: the necessity of nonlinear fracture models.

    Science.gov (United States)

    Yang, Q D; Cox, Brian N; Nalla, Ravi K; Ritchie, R O

    2006-03-01

    Recently published data for fracture in human humeral cortical bone are analyzed using cohesive-zone models to deal with the nonlinear processes of material failure. Such models represent the nonlinear deformation processes involved in fracture by cohesive tractions exerted by the failing material along a fracture process zone, rather than attributing all damage to a process occurring at a single point, as in conventional linear-elastic fracture mechanics (LEFM). The relationship between the tractions and the net displacement discontinuity across the process zone is hypothesized to be a material property for bone. To test this hypothesis, the cohesive law was evaluated by analyzing published load vs. load-point displacement data from one laboratory; the calibrated law was then used to predict similar data taken for a different source of bone using a different specimen geometry in a different laboratory. Further model calculations are presented to illustrate more general characteristics of the nonlinear fracture of bone and to demonstrate in particular that LEFM is not internally consistent for all cases of interest. For example, the fracture toughness of bone deduced via LEFM from test data is not necessarily a material constant, but will take different values for different crack lengths and test configurations. LEFM is valid when the crack is much longer than a certain length scale, representative of the length of the process zone in the cohesive model, which for human cortical bone ranges from 3 to 10mm. Since naturally occurring bones and the specimens used to test them are not much larger than this dimension for most relevant orientations, it is apparent that only nonlinear fracture models can give an internally consistent account of their fracture. The cohesive law is thus a more complete representation of the mechanics of material failure than the single-parameter fracture toughness and may therefore provide a superior measure of bone quality. The analysis of

  18. Critical length scales and strain localization govern the mechanical performance of multi-layer graphene assemblies.

    Science.gov (United States)

    Xia, Wenjie; Ruiz, Luis; Pugno, Nicola M; Keten, Sinan

    2016-03-17

    Multi-layer graphene assemblies (MLGs) or fibers with a staggered architecture exhibit high toughness and failure strain that surpass those of the constituent single sheets. However, how the architectural parameters such as the sheet overlap length affect these mechanical properties remains unknown due in part to the limitations of mechanical continuum models. By exploring the mechanics of MLG assemblies under tensile deformation using our established coarse-grained molecular modeling framework, we have identified three different critical interlayer overlap lengths controlling the strength, plastic stress, and toughness of MLGs, respectively. The shortest critical length scale L governs the strength of the assembly as predicted by the shear-lag model. The intermediate critical length L is associated with a dynamic frictional process that governs the strain localization propensity of the assembly, and hence the failure strain. The largest critical length scale L corresponds to the overlap length necessary to achieve 90% of the maximum theoretical toughness of the material. Our analyses provide the general guidelines for tuning the constitutive properties and toughness of multilayer 2D nanomaterials using elasticity, interlayer adhesion energy and geometry as molecular design parameters. PMID:26935048

  19. Diffusion length and resistivity distribution characteristics of silicon wafer by photoluminescence

    International Nuclear Information System (INIS)

    Highlights: • Analytical photoluminescence efficiency calculation and PL intensity ratio method are developed. • Wafer resistivity and diffusion length characteristics are investigated by PL intensity ratio. • PL intensity is well correlated with resistivity, diffusion length or defect density on wafer measurement. - Abstract: Photoluminescence is a convenient, contactless method to characterize semiconductors. Its use for room-temperature silicon characterization has only recently been implemented. We have developed the PL efficiency theory as a function of substrate doping densities, bulk trap density, photon flux density, and reflectance and compared it with experimental data initially for bulk Si wafers. New developed PL intensity ratio method is able to predict the silicon wafer properties, such as doping densities, minority carrier diffusion length and bulk trap density

  20. Nano-scaled graphene platelets with a high length-to-width aspect ratio

    Science.gov (United States)

    Zhamu, Aruna; Guo, Jiusheng; Jang, Bor Z.

    2010-09-07

    This invention provides a nano-scaled graphene platelet (NGP) having a thickness no greater than 100 nm and a length-to-width ratio no less than 3 (preferably greater than 10). The NGP with a high length-to-width ratio can be prepared by using a method comprising (a) intercalating a carbon fiber or graphite fiber with an intercalate to form an intercalated fiber; (b) exfoliating the intercalated fiber to obtain an exfoliated fiber comprising graphene sheets or flakes; and (c) separating the graphene sheets or flakes to obtain nano-scaled graphene platelets. The invention also provides a nanocomposite material comprising an NGP with a high length-to-width ratio. Such a nanocomposite can become electrically conductive with a small weight fraction of NGPs. Conductive composites are particularly useful for shielding of sensitive electronic equipment against electromagnetic interference (EMI) or radio frequency interference (RFI), and for electrostatic charge dissipation.

  1. Infrared length scale and extrapolations for the no-core shell model

    CERN Document Server

    Wendt, K A; Papenbrock, T; Sääf, D

    2015-01-01

    We precisely determine the infrared (IR) length scale of the no-core shell model (NCSM). In the NCSM, the $A$-body Hilbert space is truncated by the total energy, and the IR length can be determined by equating the intrinsic kinetic energy of $A$ nucleons in the NCSM space to that of $A$ nucleons in a $3(A-1)$-dimensional hyper-radial well with a Dirichlet boundary condition for the hyper radius. We demonstrate that this procedure indeed yields a very precise IR length by performing large-scale NCSM calculations for $^{6}$Li. We apply our result and perform accurate IR extrapolations for bound states of $^{4}$He, $^{6}$He, $^{6}$Li, $^{7}$Li. We also attempt to extrapolate NCSM results for $^{10}$B and $^{16}$O with bare interactions from chiral effective field theory over tens of MeV.

  2. Infrared length scale and extrapolations for the no-core shell model

    Science.gov (United States)

    Wendt, K. A.; Forssén, C.; Papenbrock, T.; Sääf, D.

    2015-06-01

    We precisely determine the infrared (IR) length scale of the no-core shell model (NCSM). In the NCSM, the A -body Hilbert space is truncated by the total energy, and the IR length can be determined by equating the intrinsic kinetic energy of A nucleons in the NCSM space to that of A nucleons in a 3 (A -1 ) -dimensional hyper-radial well with a Dirichlet boundary condition for the hyper radius. We demonstrate that this procedure indeed yields a very precise IR length by performing large-scale NCSM calculations for 6Li. We apply our result and perform accurate IR extrapolations for bound states of 4He,6He,6Li , and 7Li . We also attempt to extrapolate NCSM results for 10B and 16O with bare interactions from chiral effective field theory over tens of MeV.

  3. A modification in the technique of computing average lengths from the scales of fishes

    Science.gov (United States)

    Van Oosten, John

    1953-01-01

    In virtually all the studies that employ scales, otollths, or bony structures to obtain the growth history of fishes, it has been the custom to compute lengths for each individual fish and from these data obtain the average growth rates for any particular group. This method involves a considerable amount of mathematical manipulation, time, and effort. Theoretically it should be possible to obtain the same information simply by averaging the scale measurements for each year of life and the length of the fish employed and computing the average lengths from these data. This method would eliminate all calculations for individual fish. Although Van Oosten (1929: 338) pointed out many years ago the validity of this method of computation, his statements apparently have been overlooked by subsequent investigators.

  4. Length-scale dependent ensemble-averaged conductance of a 1D disordered conductor: Conductance minimum

    International Nuclear Information System (INIS)

    Exact numerical calculation of ensemble averaged length-scale dependent conductance for the 1D Anderson model is shown to support an earlier conjecture for a conductance minimum. Numerical results can be understood in terms of the Thouless expression for the conductance and the Wigner level-spacing statistics. (author). 8 refs, 2 figs

  5. Reversible aggregation on nanometer length scales (from simple salts to viruses)

    NARCIS (Netherlands)

    Validzic, I.J.

    2004-01-01

    This thesis focuses on issues concerning the reversible self-assembly on nanometer length scales, starting from simple salt without and in the presence of high and low molecular weight additives, over the clusters of molybdenum oxide and finishing with the rodlike viruses. All those systems are exam

  6. Studying fractal geometry on submicron length scales by small-angle scattering

    Energy Technology Data Exchange (ETDEWEB)

    Wong, P.; Lin, J.

    1988-08-01

    Recent studies have shown that internal surfaces of porous geological materials, such as rocks and lignite coals, can be described by fractals down to atomic length scales. In this paper, the basic properties of self-similar and self-affine fractals are reviewed and how fractal dimensions can be measured by small-angle scattering experiments are discussed.

  7. Studying fractal geometry on submicron length scales by small-angle scattering

    International Nuclear Information System (INIS)

    Recent studies have shown that internal surfaces of porous geological materials, such as rocks and lignite coals, can be described by fractals down to atomic length scales. In this paper, the basic properties of self-similar and self-affine fractals are reviewed and how fractal dimensions can be measured by small-angle scattering experiments are discussed

  8. Wind direction variations in the natural wind – A new length scale

    DEFF Research Database (Denmark)

    Johansson, Jens; Christensen, Silas Sverre

    2016-01-01

    During an observation period of e.g. 10min, the wind direction will differ from its mean direction for short periods of time, and a body of air will pass by from that direction before the direction changes once again. The present paper introduces a new length scale which we have labeled the angul...

  9. Determining the optimal smoothing length scale for actuator line models of wind turbine blades

    Science.gov (United States)

    Martinez, Luis; Meneveau, Charles

    2015-11-01

    The actuator line model (ALM) is a widely used tool for simulating wind turbines when performing Large-Eddy Simulations. The ALM uses a smearing kernel ηɛ = 1 /ɛ3π 3 / 2 exp (-r2 /ɛ2) , where r is the distance to an actuator point, and ɛ is the smoothing length scale which establishes the kernel width, to project the lift and drag forces onto the grid. In this work, we develop formulations to establish the optimum value of the smoothing length scale ɛ, based on physical arguments, instead of purely numerical constraints. This parameter has a very important role in the ALM, to provide a length scale, which may, for example, be related to the chord of the airfoil being studied. In the proposed approach, we compare features (such as vertical pressure gradient) of a potential flow solution for flow over a lifting surface with features of the solution of the Euler equations with a body force term. The potential flow solution over a lifting surface is used as a general representation of an airfoil. The method presented aims to minimize the difference between these features of the flow fields as a function of the smearing length scale (ɛ), in order to obtain the optimum value. This work is supported by NSF (IGERT and IIA-1243482) and computations use XSEDE resources.

  10. SCALE-LENGTH DETERMINATIONS OF EXPONENTIAL DISKS OF SPIRAL GALAXIES - A COMPARISON

    NARCIS (Netherlands)

    KNAPEN, JH; VANDERKRUIT, PC

    1991-01-01

    Values for the scale lengths h of the exponential discs of spiral galaxies, as found by different authors, have been compared. For a given galaxy, two published values for h may show a discrepancy of almost a factor two. The average value of the discrepancy for more than 120 galaxies is 23%, with a

  11. Fracture theory based on the concept of characteristic fracture length of materials

    Institute of Scientific and Technical Information of China (English)

    MUTOH; Yoshiharu

    2009-01-01

    Fracture theory is a classic,but not a well-dealt with,difficulty in solid mechanics. This paper has proposed the concept of characteristic fracture length of materials from the fact that fracture happens with area failure rather than point failure in materials. A unified theory is then proposed,which can be applied both to smooth and defected materials (whether with micro or macro defects). Brittle fracture tests with specimens of different sizes of holes are carried out to examine the fracture theory. It is found that the fracture stresses obtained by experiments agree well with those predicated by the presented fracture theory. Though the brittle fracture is the focus of the paper,the concept of characteristic length can be easily extended to fatigue or other failure problems.

  12. Scale and time dependence of serial correlations in word-length time series of written texts

    Science.gov (United States)

    Rodriguez, E.; Aguilar-Cornejo, M.; Femat, R.; Alvarez-Ramirez, J.

    2014-11-01

    This work considered the quantitative analysis of large written texts. To this end, the text was converted into a time series by taking the sequence of word lengths. The detrended fluctuation analysis (DFA) was used for characterizing long-range serial correlations of the time series. To this end, the DFA was implemented within a rolling window framework for estimating the variations of correlations, quantified in terms of the scaling exponent, strength along the text. Also, a filtering derivative was used to compute the dependence of the scaling exponent relative to the scale. The analysis was applied to three famous English-written literary narrations; namely, Alice in Wonderland (by Lewis Carrol), Dracula (by Bram Stoker) and Sense and Sensibility (by Jane Austen). The results showed that high correlations appear for scales of about 50-200 words, suggesting that at these scales the text contains the stronger coherence. The scaling exponent was not constant along the text, showing important variations with apparent cyclical behavior. An interesting coincidence between the scaling exponent variations and changes in narrative units (e.g., chapters) was found. This suggests that the scaling exponent obtained from the DFA is able to detect changes in narration structure as expressed by the usage of words of different lengths.

  13. Scalar wave propagation in random amplifying media: Influence of localization effects on length and time scales and threshold behavior

    International Nuclear Information System (INIS)

    We present a detailed discussion of scalar wave propagation and light intensity transport in three-dimensional random dielectric media with optical gain. The intrinsic length and time scales of such amplifying systems are studied and comprehensively discussed as well as the threshold characteristics of single- and two-particle propagators. Our semianalytical theory is based on a self-consistent Cooperon resummation, representing the repeated self-interference, and incorporates as well optical gain and absorption, modeled in a semianalytical way by a finite imaginary part of the dielectric function. Energy conservation in terms of a generalized Ward identity is taken into account.

  14. Advancing multiscale structural mapping of the brain through fluorescence imaging and analysis across length scales.

    Science.gov (United States)

    Hogstrom, L J; Guo, S M; Murugadoss, K; Bathe, M

    2016-02-01

    Brain function emerges from hierarchical neuronal structure that spans orders of magnitude in length scale, from the nanometre-scale organization of synaptic proteins to the macroscopic wiring of neuronal circuits. Because the synaptic electrochemical signal transmission that drives brain function ultimately relies on the organization of neuronal circuits, understanding brain function requires an understanding of the principles that determine hierarchical neuronal structure in living or intact organisms. Recent advances in fluorescence imaging now enable quantitative characterization of neuronal structure across length scales, ranging from single-molecule localization using super-resolution imaging to whole-brain imaging using light-sheet microscopy on cleared samples. These tools, together with correlative electron microscopy and magnetic resonance imaging at the nanoscopic and macroscopic scales, respectively, now facilitate our ability to probe brain structure across its full range of length scales with cellular and molecular specificity. As these imaging datasets become increasingly accessible to researchers, novel statistical and computational frameworks will play an increasing role in efforts to relate hierarchical brain structure to its function. In this perspective, we discuss several prominent experimental advances that are ushering in a new era of quantitative fluorescence-based imaging in neuroscience along with novel computational and statistical strategies that are helping to distil our understanding of complex brain structure. PMID:26855758

  15. Length Scales and Turbulent Properties of Magnetic Fields in Simulated Galaxy Clusters

    CERN Document Server

    Egan, Hilary; Hallman, Eric; Burns, Jack; Xu, Hao; Collins, David; Li, Hui; Norman, Michael L

    2016-01-01

    Additional physics beyond standard hydrodynamics is needed to fully model the intracluster medium (ICM); however, as we move to more sophisticated models, it is important to consider the role of magnetic fields and the way the fluid approximation breaks down. This paper represents a first step towards developing a self-consistent model of the ICM by characterizing the statistical properties of magnetic fields in cosmological simulations of galaxy clusters. We find that plasma conditions are largely homogeneous across a range of cluster masses and relaxation states. We also find that the magnetic field length scales are resolution dependent and not based on any particular physical process. Energy transfer mechanisms and scales are also identified, and imply the existence of small scale dynamo action. The scales of the small scale dynamo are resolution limited and driven by numerical resistivity and viscosity.

  16. Scaling analysis of random walks with persistence lengths: Application to self-avoiding walks

    Science.gov (United States)

    Granzotti, C. R. F.; Martinez, A. S.; da Silva, M. A. A.

    2016-05-01

    We develop an approach for performing scaling analysis of N -step random walks (RWs). The mean square end-to-end distance, , is written in terms of inner persistence lengths (IPLs), which we define by the ensemble averages of dot products between the walker's position and displacement vectors, at the j th step. For RW models statistically invariant under orthogonal transformations, we analytically introduce a relation between and the persistence length, λN, which is defined as the mean end-to-end vector projection in the first step direction. For self-avoiding walks (SAWs) on 2D and 3D lattices we introduce a series expansion for λN, and by Monte Carlo simulations we find that λ∞ is equal to a constant; the scaling corrections for λN can be second- and higher-order corrections to scaling for . Building SAWs with typically 100 steps, we estimate the exponents ν0 and Δ1 from the IPL behavior as function of j . The obtained results are in excellent agreement with those in the literature. This shows that only an ensemble of paths with the same length is sufficient for determining the scaling behavior of , being that the whole information needed is contained in the inner part of the paths.

  17. The role of mesoscale eddies time and length scales on phytoplankton production

    Directory of Open Access Journals (Sweden)

    V. Pérez-Muñuzuri

    2010-03-01

    Full Text Available Horizontal mixing has been found to play a crucial role in the development of spatial plankton structures in the ocean. We study the influence of time and length scales of two different horizontal two-dimensional (2-D flows on the growth of a single phytoplankton patch. To that end, we use a coupled model consisting of a standard three component ecological NPZ model and a flow model able to mimic the mesoscale structures observed in the ocean. Two hydrodynamic flow models are used: a flow based on Gaussian correlated noise, for which the Eulerian length and time scales can be easily controlled, and a multiscale velocity field derived from altimetry data in the North Atlantic ocean. We find the optimal time and length scales for the Gaussian flow model favouring the plankton spread. These results are used for an analysis of a more realistic altimetry flow. We discuss the findings in terms of the time scale of the NPZ model, the qualitative interaction of the flow with the reaction front and a Finite-Time Lyapunov Exponent analysis.

  18. Scaling Between Localization Length and TC in Disordered YBa2Cu3 O6.9

    Science.gov (United States)

    Gauzzi, Andrea; Pavuna, Davor

    We quantitatively study the effect of growth-induced reduction of long range structural order on the superconducting transition in epitaxial YBa2Cu3O6.9 films. The corresponding reduction of structural coherence length rc is determined from the width of X-ray diffraction rocking curves. Tc measurements in the films give evidence for the validity of the empirical scaling relation ΔTc~ rc,ab-2, where ΔTc is the disorder-induced reduction of Tc and rc,ab is the structural coherence length in the ab-plane. To explain this algebraic law we propose a simple phenomenological model based on the disorder-induced localization of the charge carriers within each ordered domain of size rc,ab. This picture enables us to precisely determine the Ginzburg-Landau superconducting coherence length in the ab-plane, and we obtain ξab=1.41±0.04 nm.

  19. Scale-lengths and instabilities in magnetized classical and relativistic plasma fluid models

    International Nuclear Information System (INIS)

    The validity of the traditional plasma continuum is predicated on a hierarchy of scale-lengths, with the Debye length being considered to be effectively unresolvable in the continuum limit. In this article, we revisit the strong magnetic field case in which the Larmor radius is comparable or smaller than the Debye length in the classical plasma, and also for a relativistic plasma. Fresh insight into the validity of the continuum assumption in each case is offered, including a fluid limit on the Alfvén speed that may impose restrictions on the validity of magnetohydrodynamics (MHD) in some solar and fusion contexts. Additional implications concerning the role of the firehose instability are also explored. (paper)

  20. Interaction-Induced Characteristic Length in Strongly Many-Body Localized Systems

    CERN Document Server

    He, Rong-Qiang

    2016-01-01

    We propose a numerical method for explicitly constructing a complete set of local integrals of motion (LIOM) and definitely show the existence of LIOM for strongly many-body localized systems. The method starts with a complete set of maximally localized guessed LIOM, gradually deforms it into a complete set of true LIOM. By using this method we find that for strongly disordered and weakly interacting systems, there are two characteristic lengths in the LIOM. The first one is governed by disorder and is of Anderson-localization nature. The second one is induced by interaction but independent of the strength of interaction, showing a nonperturbative nature. We prove that the entanglement and correlation in any eigenstate extend not longer than twice the second length.

  1. Multiple-length-scale patterning of magnetic nanoparticles by stamp assisted deposition

    International Nuclear Information System (INIS)

    Control of the size and spatial distribution of materials at multiple length scales is one of the most compelling issues in nanotechnology research. We report a multiple-length-scale patterning of pure magnetic particles as well as biocompatible magnetic particles based on a printing technique named micro-injection molding in capillaries. The magnetic particles were prepared by a technique of co-precipitation of ferric and ferrous salts in an alkali medium. We demonstrate that the morphology and the size of the patterning nanoparticles can be controlled by simply controlling the concentration of the solution. Our method exploits the self-organization of the nanoparticles in a solution confined between a stamp and the surfaces of a substrate, exploiting confinement and competing interactions between the adsorbate and the substrate. Our approach represents a remarkable example of an integrated top-down/bottom-up process

  2. Phase field modelling of stressed grain growth: Analytical study and the effect of microstructural length scale

    Energy Technology Data Exchange (ETDEWEB)

    Jamshidian, M., E-mail: mostafa.jamshidian@gmail.com [Department of Mechanical Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Institute of Structural Mechanics, Bauhaus-University Weimar, Marienstrasse 15, 99423 Weimar (Germany); Rabczuk, T., E-mail: timon.rabczuk@uni-weimar.de [Institute of Structural Mechanics, Bauhaus-University Weimar, Marienstrasse 15, 99423 Weimar (Germany); School of Civil, Environmental and Architectural Engineering, Korea University, Seoul (Korea, Republic of)

    2014-03-15

    We establish the correlation between the diffuse interface and sharp interface descriptions for stressed grain boundary migration by presenting analytical solutions for stressed migration of a circular grain boundary in a bicrystalline phase field domain. The validity and accuracy of the phase field model is investigated by comparing the phase field simulation results against analytical solutions. The phase field model can reproduce precise boundary kinetics and stress evolution provided that a thermodynamically consistent theory and proper expressions for model parameters in terms of physical material properties are employed. Quantitative phase field simulations are then employed to investigate the effect of microstructural length scale on microstructure and texture evolution by stressed grain growth in an elastically deformed polycrystalline aggregate. The simulation results reveal a transitional behaviour from normal to abnormal grain growth by increasing the microstructural length scale.

  3. Cleavage of silicon by laser-based shock waves: Interpretation by nanoscopic length scales

    International Nuclear Information System (INIS)

    Cleavage along the weakest Si{1 1 1} cleavage plane is measured by impulsive fracture using surface acoustic waves (SAWs) with steep shock fronts, generated by pulsed laser irradiation and recorded with a laser probe–beam-deflection setup. The theoretical cleavage strength, obtained by ab initio calculations for perfect single-crystal silicon lattices is compared with the strength resulting from an improved Polanyi–Orowan cleavage model. The critical strength of a real silicon crystal, measured by using calibrated elastic surface pulses with shocks, was employed to extract the corresponding critical length scale characterizing the cleavage process on the basis of the modified cleavage model. The extracted length scale of 7 nm can be connected with the size of the microstructural defect initiating failure. Usually stress generating surface defects are responsible for the nucleation of brittle fracture, especially in nanoscale systems with large surface areas.

  4. Phase field modelling of stressed grain growth: Analytical study and the effect of microstructural length scale

    International Nuclear Information System (INIS)

    We establish the correlation between the diffuse interface and sharp interface descriptions for stressed grain boundary migration by presenting analytical solutions for stressed migration of a circular grain boundary in a bicrystalline phase field domain. The validity and accuracy of the phase field model is investigated by comparing the phase field simulation results against analytical solutions. The phase field model can reproduce precise boundary kinetics and stress evolution provided that a thermodynamically consistent theory and proper expressions for model parameters in terms of physical material properties are employed. Quantitative phase field simulations are then employed to investigate the effect of microstructural length scale on microstructure and texture evolution by stressed grain growth in an elastically deformed polycrystalline aggregate. The simulation results reveal a transitional behaviour from normal to abnormal grain growth by increasing the microstructural length scale

  5. Gas-filled targets for large scale-length plasma interaction experiments on Nova

    International Nuclear Information System (INIS)

    Stimulated Brillouin backscatter from large scale-length gas-filled targets has been measured on the Nova laser. These targets were designed to approximate conditions in indirect drive ignition target designs in underdense plasma electron density (ne∼1021/cm3), temperature (Te>3 keV), and gradient scale lengths (Ln∼2 mm, Lv>6 mm) as well as calculated gain for stimulated Brillouin scattering (SBS). The targets used in these experiments were gas-filled balloons with polyimide walls (gasbags) and gas-filled hohlraums. Detailed characterization using x-ray imaging and x-ray and optical spectroscopy verifies that the calculated plasma conditions are achieved. Time-resolved SBS backscatter from these targets is <3% for conditions similar to ignition target designs

  6. Observing Evolution in the Supergranular Network Length Scale During Periods of Low Solar Activity

    Science.gov (United States)

    McIntosh, Scott W.; Leamon, Robert J.; Hock, Rachel A.; Rast, Mark P.; Ulrich, Roger K.

    2011-03-01

    We present the initial results of an observational study into the variation of the dominant length scale of quiet solar emission: supergranulation. The distribution of magnetic elements in the lanes that from the network affects, and reflects, the radiative energy in the plasma of the upper solar chromosphere and transition region at the magnetic network boundaries forming as a result of the relentless interaction of magnetic fields and convective motions of the Suns' interior. We demonstrate that a net difference of ~0.5 Mm in the supergranular emission length scale occurs when comparing observation cycle 22/23 and cycle 23/24 minima. This variation in scale is reproduced in the data sets of multiple space- and ground-based instruments and using different diagnostic measures. By means of extension, we consider the variation of the supergranular length scale over multiple solar minima by analyzing a subset of the Mount Wilson Solar Observatory Ca II K image record. The observations and analysis presented provide a tantalizing look at solar activity in the absence of large-scale flux emergence, offering insight into times of "extreme" solar minimum and general behavior such as the phasing and cross-dependence of different components of the spectral irradiance. Given that the modulation of the supergranular scale imprints itself in variations of the Suns' spectral irradiance, as well as in the mass and energy transport into the entire outer atmosphere, this preliminary investigation is an important step in understanding the impact of the quiet Sun on the heliospheric system.

  7. OBSERVING EVOLUTION IN THE SUPERGRANULAR NETWORK LENGTH SCALE DURING PERIODS OF LOW SOLAR ACTIVITY

    International Nuclear Information System (INIS)

    We present the initial results of an observational study into the variation of the dominant length scale of quiet solar emission: supergranulation. The distribution of magnetic elements in the lanes that from the network affects, and reflects, the radiative energy in the plasma of the upper solar chromosphere and transition region at the magnetic network boundaries forming as a result of the relentless interaction of magnetic fields and convective motions of the Suns' interior. We demonstrate that a net difference of ∼0.5 Mm in the supergranular emission length scale occurs when comparing observation cycle 22/23 and cycle 23/24 minima. This variation in scale is reproduced in the data sets of multiple space- and ground-based instruments and using different diagnostic measures. By means of extension, we consider the variation of the supergranular length scale over multiple solar minima by analyzing a subset of the Mount Wilson Solar Observatory Ca II K image record. The observations and analysis presented provide a tantalizing look at solar activity in the absence of large-scale flux emergence, offering insight into times of 'extreme' solar minimum and general behavior such as the phasing and cross-dependence of different components of the spectral irradiance. Given that the modulation of the supergranular scale imprints itself in variations of the Suns' spectral irradiance, as well as in the mass and energy transport into the entire outer atmosphere, this preliminary investigation is an important step in understanding the impact of the quiet Sun on the heliospheric system.

  8. Scaling Between Fault Length, Damaged Zone Thickness and Width of Secondary Fault Fans Derived from Fracture Mechanics

    Science.gov (United States)

    Ampuero, Jean Paul; Mao, Xiaolin

    2016-04-01

    The interaction between earthquakes, fault network geometry and fault zone structure is a key question motivating the integration of dynamic rupture and long-term crustal deformation modeling. Here, we address the scaling between fault structural properties from the perspective of dynamic and quasi-static processes involved in fault system evolution. Faults are surrounded by materials damaged through quasi-static and dynamic processes, forming damaged zones whose thickness and damage intensity may vary as a function of fault maturity and length. In the vicinity (typically less than a few hundred meters) of their principal slip surface, faults develop an "inner damage zone", usually characterized by micro-fracture observations. At a larger scale, faults develop an "outer damage zone" of secondary macroscopic fault branches at their tips, which organize into fans of splay faults. Inner damage zones can significantly affect earthquake ruptures, enhance near-field ground motions and facilitate fluid transport in the crust. Fault zone trapped waves can generate pulse-like rupture and oscillatory rupture speed, facilitate supershear rupture transition and allow for steady rupture propagation at speeds that are unstable or inadmissible in homogeneous media. The effects of a fault damage zone crucially depend on its thickness. Field observations of inner damage zone thickness as a function of cumulated slip show linear scaling at small slip but saturation at large slip, with maximum damage zone thickness of a few hundred meters. We previously developed fracture mechanics theoretical arguments and dynamic rupture simulations with off-fault inelastic deformation that predict saturation of the thickness of co-seismic damage zone controlled by the depth extent of the seismogenic zone. In essence, the stress intensity factor at the front of a rupture, which controls the distance reached by the large off-fault stresses that cause damage, scales with the shortest characteristic

  9. Transfer-matrix scaling from disorder-averaged correlation lengths for diluted Ising systems

    OpenAIRE

    de Queiroz, S. L. A.; Stinchcombe, R. B.

    1994-01-01

    A transfer matrix scaling technique is developed for randomly diluted systems, and applied to the site-diluted Ising model on a square lattice in two dimensions. For each allowed disorder configuration between two adjacent columns, the contribution of the respective transfer matrix to the decay of correlations is considered only as far as the ratio of its two largest eigenvalues, allowing an economical calculation of a configuration-averaged correlation length. Standard phenomenological-renor...

  10. Multi-Length-Scale Morphologies Driven by Mixed Additives in Porphyrin-Based Organic Photovoltaics.

    Science.gov (United States)

    Gao, Ke; Miao, Jingsheng; Xiao, Liangang; Deng, Wanyuan; Kan, Yuanyuan; Liang, Tianxiang; Wang, Cheng; Huang, Fei; Peng, Junbiao; Cao, Yong; Liu, Feng; Russell, Thomas P; Wu, Hongbin; Peng, Xiaobin

    2016-06-01

    A new category of deep-absorbing small molecules is developed. Optimized devices driven by mixed additives show a remarkable short-circuit current of ≈20 mA cm(-2) and a highest power conversion efficiency of 9.06%. A multi-length-scale morphology is formed, which is fully characterized by resonant soft X-ray scattering, high-angle annular dark film image transmission electron microscopy, etc. PMID:27062394

  11. Energy Dependence and Scaling Property of Localization Length near a Gapped Flat Band

    CERN Document Server

    Ge, Li

    2015-01-01

    Using a tight-binding model for a one-dimensional Lieb lattice, we show that the localization length near a gapped flat band behaves differently from the typical Urbach tail in a band gap: instead of reducing monotonically as the energy E moves away from the flat band energy E_{FB}, the presence of the flat band causes a nonmonotonic energy dependence of the localization length. This energy dependence follows a scaling property when the energy is within the spread (W) of uniformly distributed diagonal disorder, i.e. the localization length is only a function of (E-E_{FB})/W. Several other lattices are compared to distinguish the effect of the flat band on the localization length, where we eliminate, shift, or duplicate the flat band, without changing the dispersion relations of other bands. Using the top right element of the Green's matrix, we derive an analytical relation between the density of states and the localization length, which shines light on these properties of the latter, including a summation rul...

  12. Impact of preoperative patient characteristics on posturethroplasty recurrence: The significance of stricture length and prior treatments

    Directory of Open Access Journals (Sweden)

    Jibril Oyekunle Bello

    2016-01-01

    Full Text Available Introduction: Urethral strictures are common in urologic practice of Sub-Saharan Africa including Nigeria. We determine the rate of stricture recurrence following urethroplasty for anterior urethral strictures and evaluate preoperative variables that predict of stricture recurrence in our practice. Subjects and Methods: Thirty-six men who had urethroplasty for proven anterior urethral stricture disease between February 2012 and January 2015 were retrospectively analyzed. Preoperative factors including age, socioeconomic factors, comorbidities, etiology of strictures, stricture location, stricture length, periurethral spongiofibrosis, and prior stricture treatments were assessed for independent predictors of stricture recurrence. Results: The median age was 49.5 years (range 21-90, median stricture length was 4 cm (range 1-18 cm and the overall recurrence rate was 27.8%. Postinfectious strictures, pan urethral strictures or multiple strictures involving the penile and bulbar urethra were more common. Most patients had penile circular fasciocutaneous flap urethroplasty. Following univariate analysis of potential preoperative predictors of stricture recurrence, stricture length, and prior treatments with dilations or urethrotomies were found to be significantly associated with stricture recurrence. On multivariate analysis, they both remained statistically significant. Patients who had prior treatments had greater odds of having a recurrent stricture (odds ratio 18, 95% confidence interval [CI] 1.4-224.3. Stricture length was dichotomized based on receiver operating characteristic (ROC analysis, and strictures of length ≥5 cm had significantly greater recurrence (area under ROC curve of 0.825, 95% CI 0.690-0.960, P = 0.032. Conclusion: Patients who had prior dilatations or urethrotomies and those with long strictures particularly strictures ≥5 cm have significantly greater odds of developing a recurrence following urethroplasty in Nigerian

  13. LPI Thresholds in Longer Scale Length Plasmas Driven by the Nike Laser*

    Science.gov (United States)

    Weaver, J.; Oh, J.; Phillips, L.; Afeyan, B.; Seely, J.; Kehne, D.; Brown, C.; Obenschain, S.; Serlin, V.; Schmitt, A. J.; Feldman, U.; Holland, G.; Lehmberg, R. H.; McLean, E.; Manka, C.

    2010-11-01

    The Krypton-Fluoride (KrF) laser is an attractive driver for inertial confinement fusion due to its short wavelength (248nm), large bandwidth (1-3 THz), and beam smoothing by induced spatial incoherence. Experiments with the Nike KrF laser have demonstrated intensity thresholds for laser plasma instabilities (LPI) higher than reported for other high power lasers operating at longer wavelengths (>=351 nm). The previous Nike experiments used short pulses (350 ps FWHM) and small spots (<260 μm FWHM) that created short density scale length plasmas (Ln˜50-70 μm) from planar CH targets and demonstrated the onset of two-plasmon decay (2φp) at laser intensities ˜2x10^15 W/cm^2. This talk will present an overview of the current campaign that uses longer pulses (0.5-4.0 ns) to achieve greater density scale lengths (Ln˜100-200 μm). X-rays, emission near ^1/2φo and ^3/2φo harmonics, and reflected laser light have been monitored for onset of 2φp. The longer density scale lengths will allow better comparison to results from other laser facilities. *Work supported by DoE/NNSA and ONR.

  14. Transport in the three-dimensional Anderson model: an analysis of the dynamics at scales below the localization length

    Energy Technology Data Exchange (ETDEWEB)

    Steinigeweg, Robin [Institut fuer Theoretische Physik, Technische Universitaet Braunschweig, Mendelsohnstrasse 3, D-38106 Braunschweig (Germany); Niemeyer, Hendrik; Gemmer, Jochen, E-mail: r.steinigeweg@tu-bs.d, E-mail: jgemmer@uos.d [Fachbereich Physik, Universitaet Osnabrueck, Barbarastrasse 7, D-49069 Osnabrueck (Germany)

    2010-11-15

    Single-particle transport in disordered potentials is investigated at scales below the localization length. The dynamics at those scales is concretely analyzed for the three-dimensional Anderson model with Gaussian on-site disorder. This analysis particularly includes the dependence of characteristic transport quantities on the amount of disorder and the energy interval, e.g. the mean free path that separates ballistic and diffusive transport regimes. For these regimes mean velocities and diffusion constants are quantitatively given. Using the Boltzmann equation in the limit of weak disorder, we reveal the known energy dependences of transport quantities. By the application of the time-convolutionless projection operator technique in the limit of strong disorder, we obtain evidence for much less pronounced energy dependences. All our results are partially confirmed by the numerically exact solution of the time-dependent Schroedinger equation or by approximative numerical integrators. A comparison with other findings in the literature is also provided.

  15. Scaling method for storage vaults based on thermal-hydraulic characteristics

    International Nuclear Information System (INIS)

    Highlights: • This study investigated thermal-hydraulic characteristics of storage vault. • The relationship between heat flux and geometrical length is suggested to analyze scaling analysis. • The thermal characteristics of the original and scaled storage vaults were in good agreement. • The simulated results are a good agreement with experimental data. - Abstract: In this study, natural convection cooling phenomena in storage vaults for spent nuclear fuel were examined. The results revealed a relationship between the geometric length and heat flux of spent fuel cylinders. Such a correlation would be useful in dimensionally scaled storage vaults for experimental investigations of thermal and fluid flow properties. The relationship was applied to five scaled storage vaults, and the resulting thermal and fluid flow characteristics were investigated and compared with those of a full-scale storage vault. The thermal characteristics of the original and scaled storage vaults were in good agreement. The dimensionless temperature, dimensionless resident time, Euler number, and Richardson number were used to compare the behavior of structures with different dimensions, and the obtained data were in agreement within 5.1%. A 1/4-scale storage vault was constructed using the scaling methodology, and the temperature distribution was experimentally measured. The temperature distributions of the measured and simulated structures were found to be in good agreement, demonstrating that the proposed approach is effective for designing scaled-down storage vaults for experimental analyses

  16. Characteristic lengths for three-carrier transport with spin-flip and electron-hole recombination

    Science.gov (United States)

    Krcmar, Maja; Saslow, Wayne M.

    2016-05-01

    The exact solution of the linearized, steady-state transport equation for three-carrier systems, such as can occur for semiconductors and ionic conductors, is constructed starting from the near-equilibrium entropy-production requirements of irreversible thermodynamics. Three characteristic modes are found, one associated with electrostatic screening (which is often neglected), and two modes associated with diffusion and "reactions." For a spintronics model with up and down electrons and unpolarized holes, the "reactions" are spin-flip and electron-hole recombination. We discuss how the variations in carrier density, diffusivity, recombination rate, and spin relaxation time affect the characteristic lengths. We apply these modes to study spin-polarized surface photoabsorption.

  17. Convergence of macroscopic tongue anatomy in ruminants and scaling relationships with body mass or tongue length.

    Science.gov (United States)

    Meier, Andrea R; Schmuck, Ute; Meloro, Carlo; Clauss, Marcus; Hofmann, Reinhold R

    2016-03-01

    Various morphological measures demonstrate convergent evolution in ruminants with their natural diet, in particular with respect to the browser/grazer dichotomy. Here, we report quantitative macroanatomical measures of the tongue (length and width of specific parts) of 65 ruminant species and relate them to either body mass (BM) or total tongue length, and to the percentage of grass in the natural diet (%grass). Models without and with accounting for the phylogenetic structures of the dataset were used, and models were ranked using Akaike's Information Criterion. Scaling relationships followed geometric principles, that is, length measures scaled with BM to the power of 0.33. Models that used tongue length rather than BM as a body size proxy were consistently ranked better, indicating that using size proxies that are less susceptible to a wider variety of factors (such as BM that fluctuates with body condition) should be attempted whenever possible. The proportion of the freely mobile tongue tip of the total tongue (and hence also the corpus length) was negatively correlated to %grass, in accordance with concepts that the feeding mechanism of browsers requires more mobile tongues. It should be noted that some nonbrowsers, such as cattle, use a peculiar mechanism for grazing that also requires long, mobile tongues, but they appear to be exceptions. A larger corpus width with increasing %grass corresponds to differences in snout shape with broader snouts in grazers. The Torus linguae is longer with increasing %grass, a finding that still warrants functional interpretation. This study shows that tongue measures covary with diet in ruminants. In contrast, the shape of the tongue (straight or "hourglass-shaped" as measured by the ratio of the widest and smallest corpus width) is unrelated to diet and is influenced strongly by phylogeny. PMID:26647882

  18. Scaling of the critical free length for progressive unfolding of self-bonded graphene

    Energy Technology Data Exchange (ETDEWEB)

    Kwan, Kenny; Cranford, Steven W., E-mail: s.cranford@neu.edu [Laboratory of Nanotechnology in Civil Engineering (NICE), Department of Civil and Environmental Engineering, Northeastern University, 400 Snell Engineering, 360 Huntington Avenue, Boston, Massachusetts 02115 (United States)

    2014-05-19

    Like filled pasta, rolled or folded graphene can form a large nanocapsule surrounding a hollow interior. Use as a molecular carrier, however, requires understanding of the opening of such vessels. Here, we investigate a monolayer sheet of graphene as a theoretical trial platform for such a nanocapsule. The graphene is bonded to itself via aligned disulfide (S-S) bonds. Through theoretical analysis and atomistic modeling, we probe the critical nonbonded length (free length, L{sub crit}) that induces fracture-like progressive unfolding as a function of folding radius (R{sub i}). We show a clear linear scaling relationship between the length and radius, which can be used to determine the necessary bond density to predict mechanical opening/closing. However, stochastic dissipated energy limits any exact elastic formulation, and the required energy far exceeds the dissociation energy of the S-S bond. We account for the necessary dissipated kinetic energy through a simple scaling factor (Ω), which agrees well with computational results.

  19. Evaluation of scale effects on hydraulic characteristics of fractured rock using fracture network model

    International Nuclear Information System (INIS)

    It is important to take into account scale effects on fracture geometry if the modeling scale is much larger than the in-situ observation scale. The scale effect on fracture trace length, which is the most scale dependent parameter, is investigated using fracture maps obtained at various scales in tunnel and dam sites. We found that the distribution of fracture trace length follows negative power law distribution in regardless of locations and rock types. The hydraulic characteristics of fractured rock is also investigated by numerical analysis of discrete fracture network (DFN) model where power law distribution of fracture radius is adopted. We found that as the exponent of power law distribution become larger, the hydraulic conductivity of DFN model increases and the travel time in DFN model decreases. (author)

  20. An estimation formula for the average path length of scale-free networks

    Institute of Scientific and Technical Information of China (English)

    Li Ying; Cao Hong-Duo; Shan Xiu-Ming; Ren Yong

    2008-01-01

    A universal estimation formula for the average path length of scale free networks is given in this paper. Different from other estimation formulas, most of which use the size of network, N, as the only parameter, two parameters including N and a second parameter α are included in our formula. The parameter α is the power-law exponent, which represents the local connectivity property of a network. Because of this, the formula captures an important property that the local connectivity property at a microscopic level can determine the global connectivity of the whole network. The use of this new parameter distinguishes this approach from the other estimation formulas, and makes it a universal estimation formula, which can be applied to all types of scale-free networks. The conclusion is made that the small world feature is a derivative feature of a scale free network. If a network follows the power-law degree distribution, it must be a small world network. The power-law degree distribution property, while making the network economical, preserves the efficiency through this small world property when the network is scaled up. In other words, a real scale-free network is scaled at a relatively small cost and a relatively high efficiency, and that is the desirable result of self-organization optimization.

  1. Effects of fracture distribution and length scale on the equivalent continuum elastic compliance of fractured rock masses

    Directory of Open Access Journals (Sweden)

    Marte Gutierrez

    2015-12-01

    Full Text Available Fracture systems have strong influence on the overall mechanical behavior of fractured rock masses due to their relatively lower stiffness and shear strength than those of the rock matrix. Understanding the effects of fracture geometrical distribution, such as length, spacing, persistence and orientation, is important for quantifying the mechanical behavior of fractured rock masses. The relation between fracture geometry and the mechanical characteristics of the fractured rock mass is complicated due to the fact that the fracture geometry and mechanical behaviors of fractured rock mass are strongly dependent on the length scale. In this paper, a comprehensive study was conducted to determine the effects of fracture distribution on the equivalent continuum elastic compliance of fractured rock masses over a wide range of fracture lengths. To account for the stochastic nature of fracture distributions, three different simulation techniques involving Oda's elastic compliance tensor, Monte Carlo simulation (MCS, and suitable probability density functions (PDFs were employed to represent the elastic compliance of fractured rock masses. To yield geologically realistic results, parameters for defining fracture distributions were obtained from different geological fields. The influence of the key fracture parameters and their relations to the overall elastic behavior of the fractured rock mass were studied and discussed. A detailed study was also carried out to investigate the validity of the use of a representative element volume (REV in the equivalent continuum representation of fractured rock masses. A criterion was also proposed to determine the appropriate REV given the fracture distribution of the rock mass.

  2. Effects of fracture distribution and length scale on the equivalent continuum elastic compliance of fractured rock masses

    Institute of Scientific and Technical Information of China (English)

    Marte Gutierrez; Dong-Joon Youn

    2015-01-01

    Fracture systems have strong influence on the overall mechanical behavior of fractured rock masses due to their relatively lower stiffness and shear strength than those of the rock matrix. Understanding the effects of fracture geometrical distribution, such as length, spacing, persistence and orientation, is important for quantifying the mechanical behavior of fractured rock masses. The relation between fracture geometry and the mechanical characteristics of the fractured rock mass is complicated due to the fact that the fracture geometry and mechanical behaviors of fractured rock mass are strongly dependent on the length scale. In this paper, a comprehensive study was conducted to determine the effects of fracture distribution on the equivalent continuum elastic compliance of fractured rock masses over a wide range of fracture lengths. To account for the stochastic nature of fracture distributions, three different simulation techniques involving Oda’s elastic compliance tensor, Monte Carlo simulation (MCS), and suitable probability density functions (PDFs) were employed to represent the elastic compliance of fractured rock masses. To yield geologically realistic results, parameters for defining fracture distribu-tions were obtained from different geological fields. The influence of the key fracture parameters and their relations to the overall elastic behavior of the fractured rock mass were studied and discussed. A detailed study was also carried out to investigate the validity of the use of a representative element volume (REV) in the equivalent continuum representation of fractured rock masses. A criterion was also proposed to determine the appropriate REV given the fracture distribution of the rock mass.

  3. Condensation on superhydrophobic surfaces: the role of local energy barriers and structure length scale.

    Science.gov (United States)

    Enright, Ryan; Miljkovic, Nenad; Al-Obeidi, Ahmed; Thompson, Carl V; Wang, Evelyn N

    2012-10-01

    Water condensation on surfaces is a ubiquitous phase-change process that plays a crucial role in nature and across a range of industrial applications, including energy production, desalination, and environmental control. Nanotechnology has created opportunities to manipulate this process through the precise control of surface structure and chemistry, thus enabling the biomimicry of natural surfaces, such as the leaves of certain plant species, to realize superhydrophobic condensation. However, this "bottom-up" wetting process is inadequately described using typical global thermodynamic analyses and remains poorly understood. In this work, we elucidate, through imaging experiments on surfaces with structure length scales ranging from 100 nm to 10 μm and wetting physics, how local energy barriers are essential to understand non-equilibrium condensed droplet morphologies and demonstrate that overcoming these barriers via nucleation-mediated droplet-droplet interactions leads to the emergence of wetting states not predicted by scale-invariant global thermodynamic analysis. This mechanistic understanding offers insight into the role of surface-structure length scale, provides a quantitative basis for designing surfaces optimized for condensation in engineered systems, and promises insight into ice formation on surfaces that initiates with the condensation of subcooled water. PMID:22931378

  4. Shear strength of chromia across multiple length scales: An LDA + U study

    International Nuclear Information System (INIS)

    A method for predicting the shear strength of materials over multiple length scales is developed and tested. The method is based on renormalizing the energies and shear displacements obtained through electronic structure calculations of nanoscale models of the material of interest. All material- and size-dependent quantities are incorporated into the renormalization factors, yielding a universal model that can be applied to many materials and length scales. The model is used to predict the shear strength of Cr2O3 along three relevant slip planes and slip directions. The results demonstrate that the shear strengths of the nanoscale systems used in the calculations range from 19.4 to 29.4 GPa. These data are then renormalized to predict the shear strength of a grain that is 10 μm thick, yielding shear strengths ranging from 189 to 342 MPa. The large decrease in the shear strength with increasing grain size is consistent with the behavior of many materials. The ability to capture this change using electronic structure calculations that do not require experimental input may be useful in developing cohesive laws of novel materials for use in large-scale mechanical engineering simulations of materials failure.

  5. Length Scale Dependence of the Dynamic Properties of Hyaluronic Acid Solutions in the Presence of Salt

    Energy Technology Data Exchange (ETDEWEB)

    Horkay, Ferenc; Falus, Peter; Hecht, Anne-Marie; Geissler, Erik (CNRS-UMR); (NIH); (ILL)

    2010-12-07

    In solutions of the charged semirigid biopolymer hyaluronic acid in salt-free conditions, the diffusion coefficient D{sub NSE} measured at high transfer momentum q by neutron spin echo is more than an order of magnitude smaller than that determined by dynamic light scattering, D{sub DLS}. This behavior contrasts with neutral polymer solutions. With increasing salt content, D{sub DLS} approaches D{sub NSE}, which is independent of ionic strength. Contrary to theoretical expectation, the ion-polymer coupling, which dominates the low q dynamics of polyelectrolyte solutions, already breaks down at distance scales greater than the Debye-Hueckel length.

  6. Length Scale Dependence of the Dynamic Properties of Hyaluronic Acid Solutions in the Presence of Salt

    International Nuclear Information System (INIS)

    In solutions of the charged semirigid biopolymer hyaluronic acid in salt-free conditions, the diffusion coefficient DNSE measured at high transfer momentum q by neutron spin echo is more than an order of magnitude smaller than that determined by dynamic light scattering, DDLS. This behavior contrasts with neutral polymer solutions. With increasing salt content, DDLS approaches DNSE, which is independent of ionic strength. Contrary to theoretical expectation, the ion-polymer coupling, which dominates the low q dynamics of polyelectrolyte solutions, already breaks down at distance scales greater than the Debye-Hueckel length.

  7. Topology optimisation of manufacturable microstructural details without length scale separation using a spectral coarse basis preconditioner

    DEFF Research Database (Denmark)

    Alexandersen, Joe; Lazarov, Boyan Stefanov

    2015-01-01

    homogenisation approach. The approach takes boundary conditions into account and ensures connected andmacroscopically optimised microstructures regardless of the difference in micro- and macroscopic length scales. This results in microstruc-tures tailored for specific applications rather than specific properties.Manufacturability...... leading to massive savings in computational cost. The density-based topology optimisation approach combined with a Heaviside projection filter and a stochastic robust formulation is used on various problems, with both periodic and layered microstructures. The presented approach is shown to allow for the...

  8. Quantifying Contributions to Transport in Ionic Polymers Across Multiple Length Scales

    Science.gov (United States)

    Madsen, Louis

    Self-organized polymer membranes conduct mobile species (ions, water, alcohols, etc.) according to a hierarchy of structural motifs that span sub-nm to >10 μm in length scale. In order to comprehensively understand such materials, our group combines multiple types of NMR dynamics and transport measurements (spectroscopy, diffusometry, relaxometry, imaging) with structural information from scattering and microscopy as well as with theories of porous media,1 electrolytic transport, and oriented matter.2 In this presentation, I will discuss quantitative separation of the phenomena that govern transport in polymer membranes, from intermolecular interactions (Communications 49, 4283 - 4285 (2013).

  9. Explanation of the values of Hack's drainage basin, river length scaling exponent

    Science.gov (United States)

    Hunt, A. G.

    2015-08-01

    Percolation theory can be used to find water flow paths of least resistance. The application of percolation theory to drainage networks allows identification of the range of exponent values that describe the tortuosity of rivers in real river networks, which is then used to generate the observed scaling between drainage basin area and channel length, a relationship known as Hack's law. Such a theoretical basis for Hack's law allows interpretation of the range of exponent values based on an assessment of the heterogeneity of the substrate.

  10. Synchrotron X-Ray Scattering as a Tool for Characterising Catalysts on Multiple Length Scales

    International Nuclear Information System (INIS)

    Optimising the properties of catalysts for industrial processes requires a detailed knowledge of their structure and properties on multiple length scales. Synchrotron light sources are ideal tools for characterising catalysts for industrial R and D, providing data with high temporal and spatial resolution, under realistic operating conditions, in a non-destructive way. Here, we describe the different synchrotron techniques that can be employed to gain a wealth of complementary information, and highlight recent developments that have allowed remarkable insight to be gained into working catalytic systems. These techniques have the potential to guide future industrial catalyst design. (authors)

  11. Brief communication: Possible explanation of the values of Hack's drainage basin, river length scaling exponent

    Science.gov (United States)

    Hunt, Allen G.

    2016-04-01

    Percolation theory can be used to find water flow paths of least resistance. Application of percolation theory to drainage networks allows identification of the range of exponent values that describe the tortuosity of rivers in real river networks, which is then used to generate the observed scaling between drainage basin area and channel length, a relationship known as Hack's law. Such a theoretical basis for Hack's law may allow interpretation of the range of exponent values based on an assessment of the heterogeneity of the substrate.

  12. Atmospheric lateral and longitudinal turbulent length scales (measured at 600 to 800 meters above grade level)

    Science.gov (United States)

    Cliff, W. C.; Skarda, J. R.

    1987-01-01

    NASA's Airborne Doppler Lidar System has been used to obtain a detailed 'instantaneous' mapping of horizontal spatial wind fields at 600-800 m elevations on the east side of the San Gorgonio Pass in California, in the form of checkerboard-fashion horizontal wind vectors spaced at 300 m intervals along and normal to the flight path. Spatial autocorrelations for the lateral and longitudinal components are ensemble-averaged, and integral turbulent length scales are computed for the wind fields' longitudinal and lateral directions. The flow in the region studied does not appear to be isotropic.

  13. Flame treatment of low-density polyethylene: Surface chemistry across the length scales

    International Nuclear Information System (INIS)

    The relationship between surface chemistry and morphology of flame treated low-density polyethylene (LDPE) was studied by various characterization techniques across different length scales. The chemical composition of the surface was determined on the micrometer scale by X-ray photoelectron spectroscopy (XPS) as well as with time of flight secondary ion mass spectrometry (ToF-SIMS), while surface wettability was obtained through contact angle (CA) measurements on the millimeter scale. The surface concentration of hydroxyl, carbonyl and carboxyl groups, as a function of the 'number' of the flame treatment passes (which is proportional to the treatment time) was obtained. Moreover, a correlation was found with chemical composition and polarity, emphasizing the role of oxygen-containing functional groups introduced during the treatment. Carboxyl functional groups were specifically identified by fluorescent labeling and the results were compared with the ToF-SIMS data. In addition, atomic force microscopy (AFM) was used to evaluate changes in surface topography and roughness on the nanometer to micrometer length scales. After flame treatment, water-soluble low molecular weight oxidized materials (LMWOM), which were generated as products of oxidation and chain scission of the LDPE surface, agglomerated into small topographical mounds that were visible in the AFM micrographs. After rinsing the flame treated samples with water and ethanol, bead-like nodular surface structures were observed. The ionization state of flame treated LDPE surfaces was monitored by chemical force microscopy (CFM). The effective surface pKa values of carboxylic acid (-COOH) obtained by AFM were revealed by chemical force titration curves and the effective surface pKa values were found to be around 6

  14. Characteristic of Small Scale Food Industry Cluster in West Sumatera

    OpenAIRE

    Gunarif Taib; Santosa Santosa; Masrul Djalal; Helmi Helmi

    2014-01-01

    Clusters of small-scale food industries have different characteristics with industrial cluster in general. These characteristics need to know to develop a plan for cluster development. This study was conducted to determine charasteristics clusters of small-scale food industry, especially in West Sumatra. For the analysis of the components of industrial and technological components that affect the development of small-scale food industry cluster in West Sumatra. All variables influence the lev...

  15. Semiclassical Loop Quantum Gravity, Length Scales, and Fluctuations: A Tale of Two Coherent States

    CERN Document Server

    de Vegvar, Paul G N

    2013-01-01

    When gauge field theory coherent states for loop quantum gravity (LQG) were initially introduced, an optimized semiclassical length scale emerged, corresponding to the edge length \\epsilon\\ of a graph embedded in a given classical geometry. \\epsilon\\ was estimated to lie between the Planck scale L_P and the classical curvature radius L_C. Here \\epsilon\\ is explored in more detail. \\epsilon\\ at the Earth's surface is found to lie between 100 \\mu m and 0.7 m. The quantum fluctuating space-time strain amplitude and noise spectrum are estimated to be at least 4-1/2 orders smaller than the current experimental detectability. However, this large value for \\epsilon\\ makes regularization of the semiclassical electromagnetic Hamiltonian problematic for photons having wavelengths shorter than \\epsilon . The large \\epsilon\\ may be traced to the edge-wise tensor product of independent edge-based coherent states in the construction of the whole graph state. This provides physical grounds for recently proposed collective c...

  16. Biological membranes at large length scales: Biological applications and computational modeling

    Science.gov (United States)

    Maibaum, Lutz

    2012-10-01

    Biological membranes, such as the plasma membrane surrounding cells, perform an astonishing variety of essential functions: they provide structural support, regulate trafficking, and control endocytosis and fusion events, among others. Some of these capabilities are due to a membrane's elastic properties: at typical length scales of hundreds of nanometers, it can be thought of as a two-dimensional fluid sheet that exhibits significant fluctuations. This mesoscopic picture can be used to model several biological processes, including the formation of cellular protrusions due to interactions between the cytoskeleton and the cell membrane. We show that a membrane can bundle polymerizing actin filaments, thereby enabling the formation of tubular structures that resemble filopodia observed in motile cells. To study this and similar processes that involve the cell membrane over large length scales, we have developed a new computational model that correctly captures the effects of bending rigidity and fluidity. We show that our model exhibits an elastic response to perturbations that is consistent with the Canham-Helfrich description of lipid bilayers, while also providing a computationally efficient way to capture the effects of shape fluctuations.

  17. Magnetic studies of colossal magnetoresistance perovskites on macroscopic, mesoscopic and microscopic length scales

    Indian Academy of Sciences (India)

    S M Yusuf

    2004-07-01

    We have investigated magnetic correlations in various CMR manganites on macroscopic, mesoscopic and microscopic length scales by carrying out DC magnetization, neutron depolarization, and neutron diffraction measurements. We present here the effect of substituting Mn with Fe and La with Dy in the ferromagnetic La0.7- CaMnO3 ( ∼ 0.3 - 0.33) compounds. Neutron diffraction has been used in order to characterize the long-range magnetic order and its gradual suppression by the substitution. Neutron depolarization study has been carried out in order to bridge the gap in our understanding regarding the nature of magnetic correlation obtained from the macroscopic and microscopic measurements. In particular, our study on La0.67Ca0.33Mn0.9Fe0.1O3 has established the fact that a true double exchange mediated spin-glass is insulating. In another study of La-site ionic size effect and its disorder in (La1-Dy)0.7Ca0.3MnO3, we have investigated the evolution of the length scale of magnetic ordering with a possible microscopic explanation and the results have been compared with that for the light rare earth substituted compounds.

  18. Temperature and length scale dependence of solvophobic solvation in a single-site water-like liquid

    Science.gov (United States)

    Dowdle, John R.; Buldyrev, Sergey V.; Stanley, H. Eugene; Debenedetti, Pablo G.; Rossky, Peter J.

    2013-02-01

    The temperature and length scale dependence of solvation properties of spherical hard solvophobic solutes is investigated in the Jagla liquid, a simple liquid that consists of particles interacting via a spherically symmetric potential combining a hard core repulsion and a longer ranged soft core interaction, yet exhibits water-like anomalies. The results are compared with equivalent calculations for a model of a typical atomic liquid, the Lennard-Jones potential, and with predictions for hydrophobic solvation in water using the cavity equation of state and the extended simple point charge model. We find that the Jagla liquid captures the qualitative thermodynamic behavior of hydrophobic hydration as a function of temperature for both small and large length scale solutes. In particular, for both the Jagla liquid and water, we observe temperature-dependent enthalpy and entropy of solvation for all solute sizes as well as a negative solvation entropy for sufficiently small solutes at low temperature. This feature of water-like solvation is distinct from the strictly positive and temperature independent enthalpy and entropy of cavity solvation observed in the Lennard-Jones fluid. The results suggest that, compared to a simple liquid, it is the presence of a second thermally accessible repulsive energy scale, acting to increasingly favor larger separations for decreasing temperature, that is the essential characteristic of a liquid that favors low-density, open structures, and models hydrophobic hydration, and that it is the presence of this second energy scale that leads to the similarity in the behavior of water and the Jagla liquid. In addition, the Jagla liquid dewets surfaces of large radii of curvature less readily than the Lennard-Jones liquid, reflecting a greater flexibility or elasticity in the Jagla liquid structure than that of a typical liquid, a behavior also similar to that of water's hydrogen bonding network. The implications of the temperature and

  19. Length scale effect on the deformation microstructures of grown-in twins in copper

    DEFF Research Database (Denmark)

    Lu, Qiuhong; Sui, Manling; Huang, Xiaoxu; Li, Douxing; Hansen, Niels

    2014-01-01

    Electrodeposited copper samples composed of columnar grains subdivided by alternating twin/matrix (T/M) lamellae have been cold rolled to 30-85% reduction in thickness. The thickness of the T/M lamellae varies over a wide range from a few nanometres to about 1 m. The deformation microstructure has...... characteristics of deformation microstructure can be extended one order of magnitude from about 5 m to the sub-micrometre scale (about 0.5 m). © 2014 Taylor & Francis....

  20. A simulation procedure for light-matter interaction at different length scales

    Science.gov (United States)

    Leiner, Claude; Nemitz, Wolfgang; Wenzl, Franz P.; Hartmann, Paul; Hohenester, Ulrich; Sommer, Christian

    2012-06-01

    The development of photonic devices with tailor-made optical properties requires the control and the manipulation of light propagation within structures of different length scales, ranging from sub-wavelength to macroscopic dimensions. However, optical simulation at different length scales necessitates the combination of different simulation methods, which have to account properly for various effects such as polarization, interference, or diffraction: At dimensions much larger than the wavelength of light common ray-tracing (RT) techniques are conveniently employed, while in the subwavelength regime more sophisticated approaches, like the so-called finite-difference time-domain (FDTD) technique, are needed. Describing light propagation both in the sub-wavelength regime as well as at macroscopic length scales can only be achieved by bridging between these two approaches. In this contribution we present on the one hand a study aiming at the determination of the intermediate size range for which both simulation methods are applicable and on the other hand an approach for combining classical ray-tracing with FDTD simulation in order to handle optical elements of large sizes. Generally, the interface between RT and FDTD is restricted to very small sample areas. Nevertheless, many real world optical devices use e.g. diffractive optical elements (DOEs) having comparably large areas in the order of 1-2 mm² (or larger). Therefore, one has to develop strategies in order to handle the data transfer between FDTD and RT also for structures of such larger size scales. Our approach in this regard is based on the symmetries of the structures. In this way support programs like e.g. MATLAB can be used to replicate the near-field of a single structure and to merge it to the near-field of a larger area. Comparisons of RT and FDTD simulations in the far-field can be used to validate the physical correctness of this approach. With such procedure it is possible to optimize light

  1. Asymptotic limits of some models for sound propagation in porous media and the assignment of the pore characteristic lengths.

    Science.gov (United States)

    Horoshenkov, Kirill V; Groby, Jean-Philippe; Dazel, Olivier

    2016-05-01

    Modeling of sound propagation in porous media requires the knowledge of several intrinsic material parameters, some of which are difficult or impossible to measure directly, particularly in the case of a porous medium which is composed of pores with a wide range of scales and random interconnections. Four particular parameters which are rarely measured non-acoustically, but used extensively in a number of acoustical models, are the viscous and thermal characteristic lengths, thermal permeability, and Pride parameter. The main purpose of this work is to show how these parameters relate to the pore size distribution which is a routine characteristic measured non-acoustically. This is achieved through the analysis of the asymptotic behavior of four analytical models which have been developed previously to predict the dynamic density and/or compressibility of the equivalent fluid in a porous medium. In this work the models proposed by Johnson, Koplik, and Dashn [J. Fluid Mech. 176, 379-402 (1987)], Champoux and Allard [J. Appl. Phys. 70(4), 1975-1979 (1991)], Pride, Morgan, and Gangi [Phys. Rev. B 47, 4964-4978 (1993)], and Horoshenkov, Attenborough, and Chandler-Wilde [J. Acoust. Soc. Am. 104, 1198-1209 (1998)] are compared. The findings are then used to compare the behavior of the complex dynamic density and compressibility of the fluid in a material pore with uniform and variable cross-sections. PMID:27250142

  2. Statistical theory and transition in multiple-scale-lengths turbulence in plasmas

    International Nuclear Information System (INIS)

    The statistical theory of strong turbulence in inhomogeneous plasmas is developed for the cases where fluctuations with different scale-lengths coexist. Nonlinear interactions in the same kind of fluctuations as well as nonlinear interplay between different classes of fluctuations are kept in the analysis. Nonlinear interactions are modelled as turbulent drag, nonlinear noise and nonlinear drive, and a set of Langevin equations is formulated. With the help of an Ansatz of a large number of degrees of freedom with positive Lyapunov number, Langevin equations are solved and the fluctuation dissipation theorem in the presence of strong plasma turbulence has been derived. A case where two driving mechanisms (one for micro mode and the other for semi-micro mode) coexist is investigated. It is found that there are several states of fluctuations: in one state, the micro mode is excited and the semi-micro mode is quenched; in the other state, the semi-micro mode is excited, and the micro mode remains at finite but suppressed level. New type of turbulence transition is obtained, and a cusp type catastrophe is revealed. A phase diagram is drawn for turbulence which is composed of multiple classes of fluctuations. Influence of the inhomogeneous global radial electric field is discussed. A new insight is given for the physics of internal transport barrier. Finally, the nonlocal heat transport due to the long-wave-length fluctuations, which are noise-pumped by shorter-wave-length ones, is analyzed and the impact on transient transport problems is discussed. (author)

  3. Transfer-matrix scaling from disorder-averaged correlation lengths for diluted Ising systems

    Science.gov (United States)

    de Queiroz, S. L. A.; Stinchcombe, R. B.

    1994-10-01

    A transfer-matrix-scaling technique is developed for randomly diluted systems, and applied to the site-diluted Ising model on a square lattice in two dimensions. For each allowed disorder configuration between two adjacent columns, the contribution of the respective transfer matrix to the decay of correlations is considered only as far as the ratio of its two largest eigenvalues, allowing an economical calculation of a configuration-averaged correlation length. Standard phenomenological-renormalization procedures are then used to analyze aspects of the phase boundary which are difficult to assess accurately by alternative methods. For magnetic site concentration p close to pc, the extent of exponential behavior of the Tc×p curve is clearly seen for over two decades of variation of p-pc. Close to the pure-system limit, the exactly known reduced slope is reproduced to a very good approximation, though with nonmonotonic convergence. The averaged correlation lengths are inserted into the exponent-amplitude relationship predicted by conformal invariance to hold at criticality. The resulting exponent η remains near the pure value (1/4) for all intermediate concentrations until it crosses over to the percolation value at the threshold.

  4. Improved Estimates of the Milky Way's Disk Scale Length From Hierarchical Bayesian Techniques

    CERN Document Server

    Licquia, Timothy C

    2016-01-01

    The exponential scale length ($L_d$) of the Milky Way's (MW's) disk is a critical parameter for describing the global physical size of our Galaxy, important both for interpreting other Galactic measurements and helping us to understand how our Galaxy fits into extragalactic contexts. Unfortunately, current estimates span a wide range of values and often are statistically incompatible with one another. Here, we aim to determine an improved, aggregate estimate for $L_d$ by utilizing a hierarchical Bayesian (HB) meta-analysis technique that accounts for the possibility that any one measurement has not properly accounted for all statistical or systematic errors. Within this machinery we explore a variety of ways of modeling the nature of problematic measurements, and then use a Bayesian model averaging technique to derive net posterior distributions that incorporate any model-selection uncertainty. Our meta-analysis combines 29 different (15 visible and 14 infrared) photometric measurements of $L_d$ available in ...

  5. Scaling relation for the bond length, mass density, and packing order of water ice

    CERN Document Server

    Sun, Chang Q

    2013-01-01

    The packing order of molecules and the distance between adjacent oxygen atoms (dOO) in water and ice are most basic yet puzzling. Here we present a scaling solution for this purpose based only on the mass density (gcm-3), (Equation) where dL is the length ({\\AA}) of the O:H van der Waals bond and dH the H-O polar-covalent bond projecting on the O---O line. Validated by the measured proton symmetrization of compressed ice, dOO of water and ice, and dOO expansion at water surface, this solution confirms that the fluctuated, tetrahedrally-coordinated structure is unique for water ice.

  6. Dynamics study of attaining heavy ion beam with a scale of nanosecond pulse length in CSR

    International Nuclear Information System (INIS)

    The feasibility of attaining short pulse duration heavy ion beam with a scale of nanosecond pulse length was studied in the Heavy Ion Research Facility in Lanzhou-Cooling Storage Ring (HIRFL-CSR), such heavy ion beam can be produced by non-adiabatic compression, and it is implemented by a fast rotation in the longitudinal phase space. In this paper, the bunch compression beam dynamics of 238U72+ which the energy is 250 MeV/u, initial bunch pulse duration is 200 ns, and the initial momentum spread is 5 x 10-4 was computed with K-V envelope model, and the possible beam parameters are presented during bunch compression. The short 238U72+ bunch of 16 ns is got which can satisfy with the research of high energy density physics. (authors)

  7. A natural length scale for the glass transition of conjugated polymer film

    International Nuclear Information System (INIS)

    A study is reported of the anomalous glass transition temperature, Tg, in thin free-standing conjugated polymer films revealed by confocal Raman scattering. Full details of the dependence of Tg on film thicknesses d ranging from less than to greater than the polymer average end-to-end distance REE are presented. In contrast to ultrathin films (dEE), which always exhibit a reduction of their Tg values due to the chain confinement effect, thick films within a certain range of thicknesses distinguish themselves by presenting anomalous enhancement of two Tg values; one is interpreted as at the interface, and the other in the core. This study is strongly suggestive of a new length scale L, which lies in the range of most polymer electronic devices studied over which the physical properties of the film are greatly perturbed by the presence of free surfaces

  8. Length-scale dependent mechanical properties of Al-Cu eutectic alloy: Molecular dynamics based model and its experimental verification

    Energy Technology Data Exchange (ETDEWEB)

    Tiwary, C. S., E-mail: cst.iisc@gmail.com; Chattopadhyay, K. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Chakraborty, S.; Mahapatra, D. R. [Department of Aerospace Engineering, Indian Institute of Science, Bangalore 560012 (India)

    2014-05-28

    This paper attempts to gain an understanding of the effect of lamellar length scale on the mechanical properties of two-phase metal-intermetallic eutectic structure. We first develop a molecular dynamics model for the in-situ grown eutectic interface followed by a model of deformation of Al-Al{sub 2}Cu lamellar eutectic. Leveraging the insights obtained from the simulation on the behaviour of dislocations at different length scales of the eutectic, we present and explain the experimental results on Al-Al{sub 2}Cu eutectic with various different lamellar spacing. The physics behind the mechanism is further quantified with help of atomic level energy model for different length scale as well as different strain. An atomic level energy partitioning of the lamellae and the interface regions reveals that the energy of the lamellae core are accumulated more due to dislocations irrespective of the length-scale. Whereas the energy of the interface is accumulated more due to dislocations when the length-scale is smaller, but the trend is reversed when the length-scale is large beyond a critical size of about 80 nm.

  9. Length-scale dependent mechanical properties of Al-Cu eutectic alloy: Molecular dynamics based model and its experimental verification

    International Nuclear Information System (INIS)

    This paper attempts to gain an understanding of the effect of lamellar length scale on the mechanical properties of two-phase metal-intermetallic eutectic structure. We first develop a molecular dynamics model for the in-situ grown eutectic interface followed by a model of deformation of Al-Al2Cu lamellar eutectic. Leveraging the insights obtained from the simulation on the behaviour of dislocations at different length scales of the eutectic, we present and explain the experimental results on Al-Al2Cu eutectic with various different lamellar spacing. The physics behind the mechanism is further quantified with help of atomic level energy model for different length scale as well as different strain. An atomic level energy partitioning of the lamellae and the interface regions reveals that the energy of the lamellae core are accumulated more due to dislocations irrespective of the length-scale. Whereas the energy of the interface is accumulated more due to dislocations when the length-scale is smaller, but the trend is reversed when the length-scale is large beyond a critical size of about 80 nm.

  10. Flow Characteristics in Compact Thermal Spray Coating Systems with Minimum Length Nozzle

    Institute of Scientific and Technical Information of China (English)

    Seung-Hyun KIM; Youn-Jea KIM

    2009-01-01

    In this study,numerical analysis is performed to adopt the equivalence ratio on the high velocity oxygen fuel (HVOF) thermal spray coating systems equipped with a minimum length nozzle.The analysis is applied to investigate the axisymmetric,steady-state,turbulent,and chemically combusting flow both within the torch and in a free jet region between the torch and the substrate to be coated.The combustion is modeled using a single-step and eddy-dissipation model which assumes that the reaction rate is limited by the turbulent mixing rate of the fuel and oxidant.As the diameter of the nozzle throat is increased,the location of the Mach shock disc moves backward from the nozzle exit.As the throat diameter and the divergent portion are 6 mm and 8 mm,respectively,the pressure in the HVOF system is the lowest at the chamber and the expanding gas is steadily maintained with both high velocity and high temperature for different equivalence ratios.Thus,relatively minor amendments of the equivalence ratio and the geometry of HVOF can lead to improved control over coating characteristics.

  11. Muscle specific changes in length-force characteristics of the calf muscles in the spastic Han-Wistar rat

    DEFF Research Database (Denmark)

    Olesen, Annesofie Thorup; Jensen, Bente Rona; Uhlendorf, Toni L;

    2014-01-01

    normally-developed Han-Wistar rats. In addition, the extent of epimuscular myofascial force transmission between synergistic GA, SO and PL, as well as between the calf muscles and antagonistic tibialis anterior (TA) was investigated. Active length-force characteristics of spastic GA and PL were narrower...... with a reduced maximal active force. In contrast, active length-force characteristics of spastic SO were similar to those of controls. In reference position (90° ankle and knee angle), higher resistance to ankle dorsiflexion and increased passive stiffness was found for the spastic calf muscle group....... At optimum length, passive stiffness and passive force of spastic GA were decreased whereas those of spastic SO were increased. No mechanical interaction between the calf muscles and TA was found. As GA was lengthened, force from SO and PL declined despite a constant muscle-tendon unit length of SO...

  12. Freezing lines of colloidal Yukawa spheres. II. Local structure and characteristic lengths

    Energy Technology Data Exchange (ETDEWEB)

    Gapinski, Jacek, E-mail: gapinski@amu.edu.pl; Patkowski, Adam [Molecular Biophysics Division, Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland); NanoBioMedical Center, A. Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland); Nägele, Gerhard [Institute of Complex Systems (ICS-3), Forschungszentrum Jülich, D-52425 Jülich (Germany)

    2014-09-28

    Using the Rogers-Young (RY) integral equation scheme for the static pair correlation functions combined with the liquid-phase Hansen-Verlet freezing rule, we study the generic behavior of the radial distribution function and static structure factor of monodisperse charge-stabilized suspensions with Yukawa-type repulsive particle interactions at freezing. In a related article, labeled Paper I [J. Gapinski, G. Nägele, and A. Patkowski, J. Chem. Phys. 136, 024507 (2012)], this hybrid method was used to determine two-parameter freezing lines for experimentally controllable parameters, characteristic of suspensions of charged silica spheres in dimethylformamide. A universal scaling of the RY radial distribution function maximum is shown to apply to the liquid-bcc and liquid-fcc segments of the universal freezing line. A thorough analysis is made of the behavior of characteristic distances and wavenumbers, next-neighbor particle coordination numbers, osmotic compressibility factor, and the Ravaché-Mountain-Streett minimum-maximum radial distribution function ratio.

  13. Influence of the course boundary value problem on length scale parmeters for second-gradient continuum theories

    Energy Technology Data Exchange (ETDEWEB)

    Luscher, Darby J [Los Alamos National Laboratory; Bronkhorst, Curt A [Los Alamos National Laboratory; Mc Dowell, David L [GEORGIA TECH

    2010-12-20

    All nonlocal continuum descriptions of inelastic material response involve length scale parameters that either directly or implicitly quantify the physical dimensions of a neighborhood of response which influences the behavior at a particular point. The second-gradient continuum theories such as those developed by Germain, Toupin and Mindlin, and Eringen, and giving rise to strain-gradient plasticity, is becoming a common coarse-scale basis for homogenization of material response that respects the non local nature of heterogeneous material response. Ideally, the length scale parameters involved in such homogenization would be intrinsically associated with dominant aspects of the microstructure. However, these parameters, at least in some cases, are inextricably linked to the details of the coarse scale boundary value problem. Accordingly, they cannot be viewed as pure constitutive parameters. An example problem of multiscale homogenization is presented to underscore the dependence of second-gradient length scale parameters on the coarse scale boundary value problem, namely the multiscale response of an idealized porous microstructure. The fine scale (microstructure) comprises elastic perfectly plastic matrix with a periodic array of circular voids. This fine scale description of the problem is identical for two separate classes of coarse scale boundary value problem, viz. an extruded channel subject to compression and eventually developing plastic shear bands and a thin layer of material with larger (coarse scale) elliptical voids subject to shear deformation. Implications of the relationship between length scale parameters and the details of the coarse scale boundary value problem are discussed and ideas to ascertain such length parameters from evolving response fields are presented.

  14. Local scaling characteristics of Antarctic surface layer turbulence

    Directory of Open Access Journals (Sweden)

    S. Basu

    2010-03-01

    Full Text Available Over the past years, several studies have validated Nieuwstadt's local scaling hypothesis by utilizing turbulence observations from the mid-latitude, nocturnal stable boundary layers. In this work, we probe into the local scaling characteristics of polar, long-lived stable boundary layers by analyzing turbulence data from the South Pole region of the Antarctic Plateau.

  15. Frequency Characteristics of Double-Walled Carbon Nanotube Resonator with Different Length

    OpenAIRE

    Jun-Ha LEE; Jeong-Won KANG; Kim, Jin-Tae

    2016-01-01

    In this paper, we have conducted classical molecular dynamics simulations for DWCNTs of various wall lengths to investigate their use as ultrahigh frequency nano-mechanical resonators. We sought to determine the variations in the frequency of these resonators according to changes in the DWCNT wall lengths. For a double-walled carbon nanotube resonator with a shorter inner nanotube, the shorter inner nanotube can be considered to be a flexible core, and thus, the length influences the fundamen...

  16. Large scale atomistic simulation of size effects during nanoindentation: Dislocation length and hardness

    International Nuclear Information System (INIS)

    The present paper studies the size effects during nanoindentation in Ni thin films using large scale atomistic simulation. The main focus of this paper is to evaluate the available theoretical models of size effects during nanoindentation using atomistic simulation. First, the dislocation nucleation and evolution in the simulated samples are studied. In the next step, the plastic zone size is obtained for each sample at several indentation depths incorporating the dislocation visualization. The results show that the plastic zone size divided by the contact radius is not a constant factor and varies as the indentation depth changes. The total length of dislocations located in the plastic zone is measured in the simulated samples and compared to that of the corresponding theoretical models. The results obtained from the atomistic simulation verify the theoretical predictions of the dislocation length. Next, the variation of hardness obtained directly from the molecular dynamics outputs, which is the indentation force over the contact area, is studied. In the case of conical indenter, the theoretical predictions of hardness have been verified using both experiments and simulations, and the current simulation shows the same trend, i.e. the hardness decreases as the indentation depth increases. However, in the cases of flat indenters, the theoretical models have not been validated using any experiments or simulations. Here, in the cases of flat indenters, the simulation results verify the theoretical predictions of hardness. They show that the hardness increases as the indentation depth increases. The variation of dislocation density as a function of indentation depth is then studied. In the case of nanoindentation experiment, the validity of Taylor hardening model, i.e. the relation between the hardening and dislocation density, which has not been previously studied with full atomistic details, is investigated. Accordingly, the hardness obtained directly from the

  17. Clinical Frailty Scale in an Acute Medicine Unit: a Simple Tool That Predicts Length of Stay

    Science.gov (United States)

    Juma, Salina; Taabazuing, Mary-Margaret; Montero-Odasso, Manuel

    2016-01-01

    Background Frailty is characterized by increased vulnerability to external stressors. When frail older adults are admitted to hospital, they are at increased risk of adverse events including falls, delirium, and disability. The Clinical Frailty Scale (CFS) is a practical and efficient tool for assessing frailty; however, its ability to predict outcomes has not been well studied within the acute medical service. Objective To examine the CFS in elderly patients admitted to the acute medical ward and its association with length of stay. Design Prospective cohort study in an acute care university hospital in London, Ontario, Canada, involving 75 patients over age 65, admitted to the general internal medicine clinical teaching units (CTU). Measurements Patient demographics were collected through chart review, and CFS score was assigned to each patient after brief clinician assessment. The CFS ranges from 1 (very fit) to 9 (terminally ill) based on descriptors and pictographs of activity and functional status. The CFS was collapsed into three categories: non-frail (CFS 1–4), mild-to-moderately frail (CFS 5–6), and severely frail (CFS 7–8). Outcomes of length of stay and 90-day readmission were gathered through the LHSC electronic patient record. Results Severe frailty was associated with longer lengths of stay (Mean = 12.6 ± 12.7 days) compared to mild-to-moderate frailty (mean = 11.2 ± 10.8 days), and non-frailty (mean = 4.1 ± 2.1 days, p = .014). This finding was significant after adjusting for age, sex, and number of medications. Participants with higher frailty scores showed higher readmission rates when compared with those with no frailty (31.2% for severely frail, vs. 34.2% for mild-to-moderately frail vs. 19% for non-frail) although there was no significant difference in the adjusted analysis. Conclusion The CFS helped identify patients that are more likely to have prolonged hospital stays on the acute medical ward. The CFS is an easy to use tool which

  18. Hydrodynamic interactions and Brownian forces in colloidal suspensions: Coarse-graining over time and length scales

    Science.gov (United States)

    Padding, J. T.; Louis, A. A.

    2006-09-01

    We describe in detail how to implement a coarse-grained hybrid molecular dynamics and stochastic rotation dynamics simulation technique that captures the combined effects of Brownian and hydrodynamic forces in colloidal suspensions. The importance of carefully tuning the simulation parameters to correctly resolve the multiple time and length scales of this problem is emphasized. We systematically analyze how our coarse-graining scheme resolves dimensionless hydrodynamic numbers such as the Reynolds number Re, which indicates the importance of inertial effects, the Schmidt number Sc, which indicates whether momentum transport is liquidlike or gaslike, the Mach number, which measures compressibility effects, the Knudsen number, which describes the importance of noncontinuum molecular effects, and the Peclet number, which describes the relative effects of convective and diffusive transport. With these dimensionless numbers in the correct regime the many Brownian and hydrodynamic time scales can be telescoped together to maximize computational efficiency while still correctly resolving the physically relevant processes. We also show how to control a number of numerical artifacts, such as finite-size effects and solvent-induced attractive depletion interactions. When all these considerations are properly taken into account, the measured colloidal velocity autocorrelation functions and related self-diffusion and friction coefficients compare quantitatively with theoretical calculations. By contrast, these calculations demonstrate that, notwithstanding its seductive simplicity, the basic Langevin equation does a remarkably poor job of capturing the decay rate of the velocity autocorrelation function in the colloidal regime, strongly underestimating it at short times and strongly overestimating it at long times. Finally, we discuss in detail how to map the parameters of our method onto physical systems and from this extract more general lessons—keeping in mind that there

  19. Poroelastic response of articular cartilage by nanoindentation creep tests at different characteristic lengths.

    Science.gov (United States)

    Taffetani, M; Gottardi, R; Gastaldi, D; Raiteri, R; Vena, P

    2014-07-01

    Nanoindentation is an experimental technique which is attracting increasing interests for the mechanical characterization of articular cartilage. In particular, time dependent mechanical responses due to fluid flow through the porous matrix can be quantitatively investigated by nanoindentation experiments at different penetration depths and/or by using different probe sizes. The aim of this paper is to provide a framework for the quantitative interpretation of the poroelastic response of articular cartilage subjected to creep nanoindentation tests. To this purpose, multiload creep tests using spherical indenters have been carried out on saturated samples of mature bovine articular cartilage achieving two main quantitative results. First, the dependence of indentation modulus in the drained state (at equilibrium) on the tip radius: a value of 500 kPa has been found using the large tip (400 μm radius) and of 1.7 MPa using the smaller one (25 μm). Secon, the permeability at microscopic scale was estimated at values ranging from 4.5×10(-16) m(4)/N s to 0.1×10(-16) m(4)/N s, from low to high equivalent deformation. Consistently with a poroelastic behavior, the size-dependent response of the indenter displacement disappears when characteristic size and permeability are accounted for. For comparison purposes, the same protocol was applied to intrinsically viscoelastic homogeneous samples of polydimethylsiloxane (PDMS): both indentation modulus and time response have been found size-independent. PMID:24814573

  20. Low frequency energy scavenging using sub-wave length scale acousto-elastic metamaterial

    Directory of Open Access Journals (Sweden)

    Riaz U. Ahmed

    2014-11-01

    Full Text Available This letter presents the possibility of energy scavenging (ES utilizing the physics of acousto-elastic metamaterial (AEMM at low frequencies (<∼3KHz. It is proposed to use the AEMM in a dual mode (Acoustic Filter and Energy Harvester, simultaneously. AEMM’s are typically reported for filtering acoustic waves by trapping or guiding the acoustic energy, whereas this letter shows that the dynamic energy trapped inside the soft constituent (matrix of metamaterials can be significantly harvested by strategically embedding piezoelectric wafers in the matrix. With unit cell AEMM model, we experimentally asserted that at lower acoustic frequencies (< ∼3 KHz, maximum power in the micro Watts (∼35µW range can be generated, whereas, recently reported phononic crystal based metamaterials harvested only nano Watt (∼30nW power against 10KΩ resistive load. Efficient energy scavengers at low acoustic frequencies are almost absent due to large required size relevant to the acoustic wavelength. Here we report sub wave length scale energy scavengers utilizing the coupled physics of local, structural and matrix resonances. Upon validation of the argument through analytical, numerical and experimental studies, a multi-frequency energy scavenger (ES with multi-cell model is designed with varying geometrical properties capable of scavenging energy (power output from ∼10µW – ∼90µW between 0.2 KHz and 1.5 KHz acoustic frequencies.

  1. Surface-immobilized hydrogel patterns on length scales from micrometer to nanometer

    Science.gov (United States)

    Zeira, Assaf

    The present work concentrates on the study of pattern generation and transfer processes of monolayer covered surfaces, deriving from the basic working concept of Constructive Lithography. As an advancement of constructive lithography, we developed a direct, one-step printing (contact electrochemical printing, CEP) and replication (contact electrochemical replication, CER) of hydrophilic organic monolayer patterns surrounded by a hydrophobic monolayer background. In addition, we present a process of transfer of metal between two contacting solid surfaces to predefined monolayer template pattern sites (contact electrochemical transfer, CET). This thesis shows that CEP, CER, and CET may be implemented under a variety of different experimental conditions, regardless of whether the initial "master" pattern was created by a parallel (fast) or serial (slow) patterning process. CEP and CER also posses the unique attractive property that each replica may equally function as master stamp in the fabrication of additional replicas. Moreover, due to a mechanism of selfcorrection patterned surfaces produced these process are often free of defects that the initial "master" stamp may had. We finally show that the electrochemical patterning of OTS monolayers on silicon can be further extended to flexible polymeric substrate materials as well as to a variety of chemical manipulations, allowing the fabrication of tridimensional (3D) composite structures made on the basis of readily available OTS compound. The results obtained suggest that such contact electrochemical processes could be used to rapidly generate multiple copies of surface patterns spanning variable length scales, this basic approach being applicable to rigid as well as flexible substrate materials.

  2. Hybrid Simulation Strategy for Simulating Self-Assembled Morphologies at the Atomistic Length Scales

    Science.gov (United States)

    Sethuraman, Vaidyanathan; Ganesan, Venkat

    In the context of Lithium-ion batteries, an enhancement in both ionic conductivity and mechanical properties, were observed for block copolymer electrolytes with increasing MW. On the contrary, when homopolymers were used as electrolytes, the ionic conductivity decreased with increasing MW. However, the origins of such increase in conductivity are unclear and are speculated to be tied to both the morphology and the atomistic details of the copolymer themselves. Motivated by such issues, we present a strategy to create ordered morphologies of block copolymers at the atomistic level using a combination of coarse-graining and inverse coarse-graining techniques. A mapping which is developed using the long-ranged structural mapping in the disordered phases will be utilized to generate self-assembled morphologies. In particular we focus on generating self-assembled morphologies of PS-PEO at the atomistic length scales. Statics and dynamics of such self-assembled morphologies will be presented and the effect of self assembly on the transport properties of ions will also be explored. Funded by NSF.

  3. The role of reactant unmixedness, strain rate, and length scale on premixed combustor performance

    Energy Technology Data Exchange (ETDEWEB)

    Samuelsen, S.; LaRue, J.; Vilayanur, S. [Univ. of California, Irvine, CA (United States)] [and others

    1995-10-01

    Lean premixed combustion provides a means to reduce pollutant formation and increase combustion efficiency. However, fuel-air mixing is rarely uniform in space and time. This nonuniformity in concentration will lead to relative increases in pollutant formation and decreases in combustion efficiency. The nonuniformity of the concentration at the exit of the premixer has been defined by Lyons (1981) as the {open_quotes}unmixedness.{close_quotes} Although turbulence properties such as length scales and strain rate are known to effect unmixedness, the exact relationship is unknown. Evaluating this relationship and the effect of unmixedness in premixed combustion on pollutant formation and combustion efficiency are an important part of the overall goal of US Department of Energy`s Advanced Turbine Systems (ATS) program and are among the goals of the program described herein. The information obtained from ATS is intended to help to develop and commercialize gas turbines which have (1) a wide range of operation/stability, (2) a minimal amount of pollutant formation, and (3) high combustion efficiency. Specifically, with regard to pollutants, the goals are to reduce the NO{sub x} emissions by at least 10%, obtain less than 20 PPM of both CO and UHC, and increase the combustion efficiency by 5%.

  4. Length-Scale Effects and Material Models at Numerical Simulations of Nanoindentation of A Metallic Alloy

    Directory of Open Access Journals (Sweden)

    Nikolov N.

    2014-06-01

    Full Text Available Some specially designed metallic alloys crystallize during process of rapid quenching which aims their amorphization. Nevertheless, change in their mechanical properties could be seen compared to these obtained during conventional technological regimes of cooling. That attracts the attention in this elaboration. Full 3-D numerical simulations of nanoindentation process of two material models are performed. The models reflect equivalent elastic and different plastic material properties. The plastic behaviour of the first one is subjected to yield criterion of Dracker-Prager and this of the second one to yield criterion of Mises. The reported numerical results depending on the nanoindentation scale length of 1000 nanometers, suggest different adequacy of the two yield criteria to the data obtained experimentally with a Zr-Al-Cu-Ni-Mo alloy. It could be speculated that the different effects developed depending on the indenter travel of 1000 nanometers and taken into account in the two yield criteria stand behind this fact and determinate three structural levels of plastic deformation.

  5. Revealing Optical Properties of Reduced-Dimensionality Materials at Relevant Length Scales.

    Science.gov (United States)

    Ogletree, D Frank; Schuck, P James; Weber-Bargioni, Alexander F; Borys, Nicholas J; Aloni, Shaul; Bao, Wei; Barja, Sara; Lee, Jiye; Melli, Mauro; Munechika, Keiko; Whitelam, Stephan; Wickenburg, Sebastian

    2015-10-14

    Reduced-dimensionality materials for photonic and optoelectronic applications including energy conversion, solid-state lighting, sensing, and information technology are undergoing rapid development. The search for novel materials based on reduced-dimensionality is driven by new physics. Understanding and optimizing material properties requires characterization at the relevant length scale, which is often below the diffraction limit. Three important material systems are chosen for review here, all of which are under investigation at the Molecular Foundry, to illustrate the current state of the art in nanoscale optical characterization: 2D semiconducting transition metal dichalcogenides; 1D semiconducting nanowires; and energy-transfer in assemblies of 0D semiconducting nanocrystals. For each system, the key optical properties, the principal experimental techniques, and important recent results are discussed. Applications and new developments in near-field optical microscopy and spectroscopy, scanning probe microscopy, and cathodoluminescence in the electron microscope are given detailed attention. Work done at the Molecular Foundry is placed in context within the fields under review. A discussion of emerging opportunities and directions for the future closes the review. PMID:26332202

  6. Quantum electrodynamics and the electron self-energy in a deformed space with a minimal length scale

    CERN Document Server

    Silva, Apollo V; Neves, M J

    2016-01-01

    The main motivation to study models in the presence of a minimal length is to obtain a quantum field theory free of the divergences. In this way, in this paper, we have constructed a new framework for quantum electrodynamics embedded in a minimal length scale background. New operators are introduced and the Green function method was used for the solution of the field equations, i.e., the Maxwell, Klein-Gordon and Dirac equations. We have analyzed specifically the scalar field and its one loop propagator. The mass of the scalar field regularized by the minimal length was obtained. The QED Lagrangian containing a minimal length was also constructed and the divergences were analyzed. The electron and photon propagators, and the electron self-energy at one loop as a function of the minimal length was also obtained.

  7. Quantum electrodynamics and the electron self-energy in a deformed space with a minimal length scale

    Science.gov (United States)

    Silva, Apollo V.; Abreu, E. M. C.; Neves, M. J.

    2016-06-01

    The main motivation to study models in the presence of a minimal length is to obtain a quantum field theory free of the divergences. In this way, in this paper, we have constructed a new framework for quantum electrodynamics embedded in a minimal length scale background. New operators are introduced and the Green function method was used for the solution of the field equations, i.e. the Maxwell, Klein-Gordon and Dirac equations. We have analyzed specifically the scalar field and its one loop propagator. The mass of the scalar field regularized by the minimal length was obtained. The QED Lagrangian containing a minimal length was also constructed and the divergences were analyzed. The electron and photon propagators, and the electron self-energy at one loop as a function of the minimal length was also obtained.

  8. The Effect of Wing Scales on Monarch Butterfly Flight Characteristics

    Science.gov (United States)

    Shaw, Angela; Jones, Robert; Lang, Amy

    2010-11-01

    Recent research has shown that the highly flexible wings of butterflies in flapping flight develop vortices along their leading and trailing edges. Butterfly scales (approximately 100 microns in length) have a shingled pattern and extend into the boundary layer. These scales, which make up approximately 3% of the body weight or less, could play a part in controlling separation and vortex formation in this unsteady, three-dimensional complex flow field. A better understanding of this mechanism may lead to bio-inspired applications for flapping wing micro-air vehicles. In this study, the flight performance of Monarch (Danaus plexippus) butterflies with and without scales was analyzed. Scales were removed from the upper and lower wing surfaces and specimens were videotaped at 600 frames per second. Variation in flapping patterns and flight fitness were observed.

  9. Frequency Characteristics of Double-Walled Carbon Nanotube Resonator with Different Length

    Directory of Open Access Journals (Sweden)

    Jun-Ha LEE

    2016-05-01

    Full Text Available In this paper, we have conducted classical molecular dynamics simulations for DWCNTs of various wall lengths to investigate their use as ultrahigh frequency nano-mechanical resonators. We sought to determine the variations in the frequency of these resonators according to changes in the DWCNT wall lengths. For a double-walled carbon nanotube resonator with a shorter inner nanotube, the shorter inner nanotube can be considered to be a flexible core, and thus, the length influences the fundamental frequency. In this paper, we analyze the variation in frequency of ultra-high frequency nano-mechnical resonators constructed from DWCNTs with different wall lengths.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.12951

  10. Diffusion effects on volume-selective NMR at small length scales

    International Nuclear Information System (INIS)

    In this thesis, the interplay between diffusion and relaxation effects in spatially selective NMR experiments at short length scales is explored. This is especially relevant in the context of both conventional and mechanically detected MRI at (sub)micron resolution in biological specimens. Recent results on selectively excited very thin slices showed an in-slice-magnetization recovery orders of magnitude faster than the longitudinal relaxation time T1. However, those experiments were run on fully relaxed samples while MRI and especially mechanically detected NMR experiments are typically run in a periodic fashion with repetition times far below T1. The main purpose of this work therefore was to extend the study of the interplay between diffusion and longitudinal relaxation to periodic excitations. In some way, this is inverse phenomenon to the DESIRE (Diffusive Enhancement of SIgnal and REsolution) approach, proposed 1992 by Lauterbur. Experiments on periodically excited thin slices were carried out at a dedicated static field gradient cryomagnet with magnetic field gradients up to 180 T/m. In order to obtain plane slices, an appropriate isosurface of the gradient magnet had to be identified. It was found at a field of 3.8 T with a gradient of 73 T/m. In this field, slices down to a thickness of 3.2 μm could be excited. The detection of the NMR signal was done using FIDs instead of echoes as the excitation bandwidth of those thin slices is sufficiently small to observe FIDs which are usually considered to be elusive to detection in such strong static field gradients. A simulation toolbox based on the full Bloch-Torrey-equation was developed to describe the excitation and the formation of NMR signals under those unusual conditions as well as the interplay of diffusion and magnetization recovery. Both the experiments and the simulations indicate that diffusion effects lead to a strongly enhanced magnetization modulation signal also under periodic excitation

  11. Recent Progress in the Study of Single Molecule Chemistry at the Nanometer Length Scale and Picosecond Time Scale

    Science.gov (United States)

    van Duyne, Richard

    2015-03-01

    During the last few years, there has been an explosion of interest and activity in the field of plasmonics. The goal of plasmonics is to control and manipulate light on the nanometer length scale using the properties of the collective electronic excitations in noble metal films or nanoparticles, known as surface plasmons. An improved understanding of the interactions between adsorbed molecules and plasmonic nanostructures (i.e., molecular plasmonics) is having a significant impact in a number of research areas including electrochemistry, surface science, catalysis for energy conversion and storage, the materials science of nanoparticles, biomedical diagnostics, art conservation science, and nanolithography. In the first part of this lecture, I will provide some background material on the basic physical concepts underlying molecular plasmonics with an emphasis on surface-enhanced Raman spectroscopy (SERS), localized surface plasmon resonance (LSPR) spectroscopy, and tip-enhanced Raman spectroscopy (TERS). In the second part of this lecture, I will focus in on three recent advances in TERS which illustrate the power of this nanoscale vibrational spectroscopy. First, new insights into the nature of the relative intensity fluctuations in single molecule tip-enhanced Raman spectroscopy (SMTERS) will be discussed. Second, our current understanding of the adsorbate surface interactions involved in the low temperature (LT), ultrahigh vacuum (UHV) TERS of the Ag tip/Rhodamine 6G (R6G) /Ag(111) system will be described. Finally, an update on our new results in coupling ultrafast lasers with TERS. This last topic illuminates a path forward toward the goal of understanding chemistry at the space-time limit.

  12. Denoising of Chinese calligraphy tablet images based on run-length statistics and structure characteristic of character strokes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun-song; YU Jin-hui; MAO Guo-hong; YE Xiu-zi

    2006-01-01

    In this paper, a novel approach is proposed for denoising of Chinese calligraphy tablet documents. The method includes two phases: First, a partial differential equations (PDE) based the total variation model and Otsu thresholding method are used to preprocess the calligraphy document image. Second, a new method based on on-length statistics and structure characteristics of Chinese characters is proposed to remove some random and ant-like noises. This includes the optimal threshold selection from histogram of run-length probability density, and improved Hough transform algorithm for line shape noise detection and removal. Examples are given in the paper to demonstrate the proposed method.

  13. Effect of the length of ligands passivating quantum dots on the electrooptical characteristics of organic light-emitting diodes

    International Nuclear Information System (INIS)

    The electrooptical characteristics of organic light-emitting diodes with quantum dots passivated with organic ligands of different lengths as emitting centers are investigated. It is established that the thickness of the ligand coating covering the quantum dots has little effect on the Förster energy transfer in the diodes, but significantly affects the direct injection of charge carriers into the quantum-dot layer. It is shown that the thickness of the passivation coating covering the quantum dots in a close-packed nanoparticle layer is deter- mined both by the length of passivating ligands and the degree of quantum-dot coverage with ligands

  14. Cross-flow ultrafiltration of colloids : characterization of the mechanisms at nanometer length scales and enhanced by ultrasound

    OpenAIRE

    Jin, Yao

    2014-01-01

    This thesis studies an ultrasonic assisted cross-flow ultrafiltration process from macro tonano scales. Different types of colloids were investigated: synthetic and natural clay dispersions,casein micelles (skim milk) and starch or cellulose nanocrystal suspensions. Firstly, flowproperties and the changes due to ultrasound (US) were investigated. Secondly, structuralorganizations at nanometer length scales in the vicinity of the membrane during filtration havebeen revealed for the first time ...

  15. Self-organization of Au–CdSe hybrid nanoflowers at different length scales via bi-functional diamine linkers

    International Nuclear Information System (INIS)

    This work introduces a series of molecular bridging bi-functional linkers to produce laterally self-assembled nanostructures of the Au–CdSe nanoflowers on different length scales ranging from 10 nm to 100 microns. Assembly of Au nanocrystals within amorphous CdSe rods is found in the early stages of the growth of the Au–CdSe nanoflowers. The Au–CdSe nanoflowers are formed through a one-pot low temperature (150 °C) process where CdSe clusters are adsorbed on the surface of the Au cores, and they then start to form multiple arms and branches resulting in flower-shaped hybrid nanostructures. More complex assembly at a micron length scale can be achieved by means of bi-functional capping agents with appropriate alkyl chain lengths, such as 1,12-diaminododecane.

  16. Self-organization of Au–CdSe hybrid nanoflowers at different length scales via bi-functional diamine linkers

    Energy Technology Data Exchange (ETDEWEB)

    AbouZeid, Khaled Mohamed [Virginia Commonwealth University, Department of Chemistry (United States); Mohamed, Mona Bakr [Cairo University, National Institute of Laser Enhanced Science (NILES) (Egypt); El-Shall, M. Samy, E-mail: mselshal@vcu.edu [Virginia Commonwealth University, Department of Chemistry (United States)

    2016-01-15

    This work introduces a series of molecular bridging bi-functional linkers to produce laterally self-assembled nanostructures of the Au–CdSe nanoflowers on different length scales ranging from 10 nm to 100 microns. Assembly of Au nanocrystals within amorphous CdSe rods is found in the early stages of the growth of the Au–CdSe nanoflowers. The Au–CdSe nanoflowers are formed through a one-pot low temperature (150 °C) process where CdSe clusters are adsorbed on the surface of the Au cores, and they then start to form multiple arms and branches resulting in flower-shaped hybrid nanostructures. More complex assembly at a micron length scale can be achieved by means of bi-functional capping agents with appropriate alkyl chain lengths, such as 1,12-diaminododecane.

  17. Hierarchical Self-Assembly of Peptide Amphiphiles: Form and Function at Multiple Length Scales

    Science.gov (United States)

    Zha, Runye Helen

    Hierarchical self-assembly, the organization of molecules into supramolecular structures of increasing size and complexity, is a potent tool for materials synthesis and requires understanding the connections of structure across multiple length scales. Herein, self-assembly of peptide amphiphiles (PAs) into nanoscopic and macroscopic materials is explored, and their anti-cancer applications are investigated. First, nanoscale assembly is examined in the context of an anti-angiogenic PA bearing the G-helix motif of maspin, a tumor suppressor protein. Assembly of this maspin-mimetic PA (MMPA) stabilizes the native G-helix conformation and improves binding to endothelial cells. Furthermore, PA nanostructures significantly increase cell adhesion to fibronectin as compared to G-helix peptide alone. Combined with its inhibitory effect on cell migration, MMPA nanostructures thus show anti-angiogenic activity on par with maspin protein in vitro and in vivo. Second, assembly of cationic PAs with hyaluronic acid (HA), an anionic polyelectrolyte, into macroscopic membranes is explored using PAs with identical formal charge but systematically varied self-assembly domains. Results suggest that membrane formation is dictated by the initial moments of component aggregation and is highly sensitive to PA molecular structure via nanoscale assembly. Specifically, PAs with beta-sheet forming residues are nanofibrous and have high surface charge density, leading to robust membranes with aligned-fiber microstructure. PAs without beta-sheet forming residues are nanospherical and have low surface charge density, leading to weak membranes with non-fibrous finger-like microstructure. Lastly, the principles of PA-HA membrane assembly are applied towards development of anti-cancer therapeutic biomaterials. Here, cytotoxic PAs bearing the epitope (KLAKLAKbeta)2 are co-assembled with non-bioactive cationic PA in order to achieve varying nanoscale morphology. These nanostructures are then

  18. Taylor-plasticity-based analysis of length scale effects in void growth

    KAUST Repository

    Liu, Junxian

    2014-09-25

    We have studied the void growth problem by employing the Taylor-based strain gradient plasticity theories, from which we have chosen the following three, namely, the mechanism-based strain gradient (MSG) plasticity (Gao et al 1999 J. Mech. Phys. Solids 47 1239, Huang et al 2000 J. Mech. Phys. Solids 48 99-128), the Taylor-based nonlocal theory (TNT; 2001 Gao and Huang 2001 Int. J. Solids Struct. 38 2615) and the conventional theory of MSG (CMSG; Huang et al 2004 Int. J. Plast. 20 753). We have addressed the following three issues which occur when plastic deformation at the void surface is unconstrained. (1) Effects of elastic deformation. Elasticity is essential for cavitation instability. It is therefore important to guarantee that the gradient term entering the Taylor model is the effective plastic strain gradient instead of the total strain gradient. We propose a simple elastic-plastic decomposition method. When the void size approaches the minimum allowable initial void size related to the maximum allowable geometrically necessary dislocation density, overestimation of the flow stress due to the negligence of the elastic strain gradient is on the order of lεY/R0 near the void surface, where l, εY and R0 are, respectively, the intrinsic material length scale, the yield strain and the initial void radius. (2) MSG intrinsic inconsistency, which was initially mentioned in Gao et al (1999 J. Mech. Phys. Solids 47 1239) but has not been the topic of follow-up studies. We realize that MSG higher-order stress arises due to the linear-strain-field approximation within the mesoscale cell with a nonzero size, lε. Simple analysis shows that within an MSG mesoscale cell near the void surface, the difference between microscale and mesoscale strains is on the order of (lε/R0)2, indicating that when lε/R0 ∼ 1.0, the higher-order stress effect can make the MSG result considerably different from the TNT or CMSG results. (3) Critical condition for cavitation instability

  19. Manufacturing test of large scale hollow capsule and long length cladding in the large scale oxide dispersion strengthened (ODS) martensitic steel

    International Nuclear Information System (INIS)

    Mass production capability of oxide dispersion strengthened (ODS) martensitic steel cladding (9Cr) has being evaluated in the Phase II of the Feasibility Studies on Commercialized Fast Reactor Cycle System. The cost for manufacturing mother tube (raw materials powder production, mechanical alloying (MA) by ball mill, canning, hot extrusion, and machining) is a dominant factor in the total cost for manufacturing ODS ferritic steel cladding. In this study, the large-sale 9Cr-ODS martensitic steel mother tube which is made with a large-scale hollow capsule, and long length claddings were manufactured, and the applicability of these processes was evaluated. Following results were obtained in this study. (1) Manufacturing the large scale mother tube in the dimension of 32 mm OD, 21 mm ID, and 2 m length has been successfully carried out using large scale hollow capsule. This mother tube has a high degree of accuracy in size. (2) The chemical composition and the micro structure of the manufactured mother tube are similar to the existing mother tube manufactured by a small scale can. And the remarkable difference between the bottom and top sides in the manufactured mother tube has not been observed. (3) The long length cladding has been successfully manufactured from the large scale mother tube which was made using a large scale hollow capsule. (4) For reducing the manufacturing cost of the ODS steel claddings, manufacturing process of the mother tubes using a large scale hollow capsules is promising. (author)

  20. Receiver-Operating-Characteristic Analysis Reveals Superiority of Scale-Dependent Wavelet and Spectral Measures for Assessing Cardiac Dysfunction

    CERN Document Server

    Thurner, S; Lowen, S B; Teich, M C; Thurner, Stefan; Feurstein, Markus C.; Lowen, Steven B.; Teich, Malvin C.

    1998-01-01

    Receiver-operating-characteristic (ROC) analysis was used to assess the suitability of various heart rate variability (HRV) measures for correctly classifying electrocardiogram records of varying lengths as normal or revealing the presence of heart failure. Scale-dependent HRV measures were found to be substantially superior to scale-independent measures (scaling exponents) for discriminating the two classes of data over a broad range of record lengths. The wavelet-coefficient standard deviation at a scale near 32 heartbeat intervals, and its spectral counterpart near 1/32 cycles per interval, provide reliable results using record lengths just minutes long. A jittered integrate-and-fire model built around a fractal Gaussian-noise kernel provides a realistic, though not perfect, simulation of heartbeat sequences.

  1. Physics on the smallest scales: an introduction to minimal length phenomenology

    Science.gov (United States)

    Sprenger, Martin; Nicolini, Piero; Bleicher, Marcus

    2012-07-01

    Many modern theories which try to unify gravity with the Standard Model of particle physics, such as e.g. string theory, propose two key modifications to the commonly known physical theories: the existence of additional space dimensions; the existence of a minimal length distance or maximal resolution. While extra dimensions have received a wide coverage in publications over the last ten years (especially due to the prediction of micro black hole production at the Large Hadron Collider), the phenomenology of models with a minimal length is still less investigated. In a summer study project for bachelor students in 2010, we have explored some phenomenological implications of the potential existence of a minimal length. In this paper, we review the idea and formalism of a quantum gravity-induced minimal length in the generalized uncertainty principle framework as well as in the coherent state approach to non-commutative geometry. These approaches are effective models which can make model-independent predictions for experiments and are ideally suited for phenomenological studies. Pedagogical examples are provided to grasp the effects of a quantum gravity-induced minimal length. This paper is intended for graduate students and non-specialists interested in quantum gravity.

  2. Scaling between superconducting critical temperature and structural coherence length in YBa2Cu3O6.9 films

    Science.gov (United States)

    Gauzzi, A.; Jönsson-Åkerman, B. Johan; Clerc-Dubois, A.; Pavuna, D.

    2000-09-01

    Measurements of critical temperature Tc in superconducting YBa2Cu3O6.9 films with reduced long-range structural order show the validity of the empirical scaling relation ΔTc propto rc-2 between disorder-induced reduction of Tc and structural coherence length rc in the ab-plane. This result is quantitatively explained by the disorder-induced confinement of the charge carriers within each ordered domain of size rc. Our analysis of the data based on this picture enables us to precisely determine the Ginzburg-Landau superconducting coherence length in the ab-plane, ξab = 1.41 ± 0.04 nm.

  3. Human learning: Power laws or multiple characteristic time scales?

    Directory of Open Access Journals (Sweden)

    Gottfried Mayer-Kress

    2006-09-01

    Full Text Available The central proposal of A. Newell and Rosenbloom (1981 was that the power law is the ubiquitous law of learning. This proposition is discussed in the context of the key factors that led to the acceptance of the power law as the function of learning. We then outline the principles of an epigenetic landscape framework for considering the role of the characteristic time scales of learning and an approach to system identification of the processes of performance dynamics. In this view, the change of performance over time is the product of a superposition of characteristic exponential time scales that reflect the influence of different processes. This theoretical approach can reproduce the traditional power law of practice – within the experimental resolution of performance data sets - but we hypothesize that this function may prove to be a special and perhaps idealized case of learning.

  4. Higher-order and length-scale statistics from DNS of a decelerated planar wall-bounded turbulent flow

    International Nuclear Information System (INIS)

    Highlights: • A DNS database of high-order moments/budgets for strained channel flow is described. • RANS modeling implications for APG boundary layers are deduced from the DNS data. • Two-point analysis confirms the advantage of an alternative one-point length scale. - Abstract: A DNS database is presented to document third- and fourth-order moments and their budgets for fully developed plane-channel flow and for strained plane-channel flow. The effect of straining has a similar effect on statistics, such as the skewness and flatness of velocities, as in an adverse-pressure-gradient (APG) boundary layer. In addition to higher-order statistics, some modeling implications are also described, including issues related to decomposition of the velocity–pressure gradient correlations, the assumption of dissipation isotropy and a fourth-order turbulence time scale. An analysis of two-point correlations along the inhomogeneous direction is made to include the effects of APG straining. This reveals the advantage of a one-point length-scale based on wall-normal velocity fluctuations as an alternative to the traditionally used length-scale based on turbulence kinetic energy. The present study should prove to be useful for turbulence modelers in need of data to develop and assess higher-than-second-order Reynolds-averaged Navier–Stokes closure models

  5. Space perception and body morphology: extent of near space scales with arm length.

    Science.gov (United States)

    Longo, Matthew R; Lourenco, Stella F

    2007-02-01

    Numerous studies have found that the near space immediately surrounding the body is represented differently than more distant space. In a previous study, we found a gradual shift in attentional bias (on a line bisection task) between near and far space (Longo and Lourenco in Neuropsychologia 44:977-981, 2006). The present study concerns the possibility that arm length relates systematically to the rate at which this gradual shift between near and far space occurs. Participants bisected lines using a laser pointer at eight distances (within and beyond arm's reach), and the rate of shift was estimated by the slope of the least-squares regression line. A negative correlation was found between the slopes and arm length; participants with longer arms showed a more gradual shift in bias with increasing distance than those with shorter arms. These results suggest that, while near space cannot be considered categorically as that within arm's reach, there is a systematic relation between the extent ("size") of near space and arm length. Arm length may constitute an intrinsic metric for the representation of near space. PMID:17256162

  6. Physics on the Smallest Scales: An Introduction to Minimal Length Phenomenology

    Science.gov (United States)

    Sprenger, Martin; Nicolini, Piero; Bleicher, Marcus

    2012-01-01

    Many modern theories which try to unify gravity with the Standard Model of particle physics, such as e.g. string theory, propose two key modifications to the commonly known physical theories: the existence of additional space dimensions; the existence of a minimal length distance or maximal resolution. While extra dimensions have received a wide…

  7. Flame Length

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — Flame length was modeled using FlamMap, an interagency fire behavior mapping and analysis program that computes potential fire behavior characteristics. The tool...

  8. The scaling of the minimum sum of edge lengths in uniformly random trees

    CERN Document Server

    Esteban, Juan Luis; Gómez-Rodríguez, Carlos

    2016-01-01

    The minimum linear arrangement problem on a network consists of finding the minimum sum of edge lengths that can be achieved when the vertices are arranged linearly. Although there are algorithms to solve this problem on trees in polynomial time, they have remained theoretical and have not been implemented in practical contexts to our knowledge. Here we use one of those algorithms to investigate the growth of this sum as a function of the size of the tree in uniformly random trees. We show that this sum is bounded above by its value in a star tree. We also show that the mean edge length grows logarithmically in optimal linear arrangements, in stark contrast to the linear growth that is expected on optimal arrangements of star trees or on random linear arrangements.

  9. Hydrodynamic simulations of long-scale-length two-plasmon–decay experiments at the Omega Laser Facility

    International Nuclear Information System (INIS)

    Direct-drive–ignition designs with plastic CH ablators create plasmas of long density scale lengths (Ln ≥ 500 μm) at the quarter-critical density (Nqc) region of the driving laser. The two-plasmon–decay (TPD) instability can exceed its threshold in such long-scale-length plasmas (LSPs). To investigate the scaling of TPD-induced hot electrons to laser intensity and plasma conditions, a series of planar experiments have been conducted at the Omega Laser Facility with 2-ns square pulses at the maximum laser energies available on OMEGA and OMEGA EP. Radiation–hydrodynamic simulations have been performed for these LSP experiments using the two-dimensional hydrocode draco. The simulated hydrodynamic evolution of such long-scale-length plasmas has been validated with the time-resolved full-aperture backscattering and Thomson-scattering measurements. draco simulations for CH ablator indicate that (1) ignition-relevant long-scale-length plasmas of Ln approaching ∼400 μm have been created; (2) the density scale length at Nqc scales as Ln(μm)≃(RDPP×I1/4/2); and (3) the electron temperature Te at Nqc scales as Te(keV)≃0.95×√(I), with the incident intensity (I) measured in 1014 W/cm2 for plasmas created on both OMEGA and OMEGA EP configurations with different-sized (RDPP) distributed phase plates. These intensity scalings are in good agreement with the self-similar model predictions. The measured conversion fraction of laser energy into hot electrons fhot is found to have a similar behavior for both configurations: a rapid growth [fhot≃fc×(Gc/4)6 for Gc hot≃fc×(Gc/4)1.2 for Gc ≥ 4, with the common wave gain is defined as Gc=3 × 10−2×IqcLnλ0/Te, where the laser intensity contributing to common-wave gain Iqc, Ln, Te at Nqc, and the laser wavelength λ0 are, respectively, measured in [1014 W/cm2], [μm], [keV], and [μm]. The saturation level fc is observed to be fc ≃ 10–2 at around Gc ≃ 4. The hot-electron temperature scales roughly linear

  10. Resolution of sub-element length scales in Brownian dynamics simulations of biopolymer networks with geometrically exact beam finite elements

    Science.gov (United States)

    Müller, Kei W.; Meier, Christoph; Wall, Wolfgang A.

    2015-12-01

    Networks of crosslinked biopolymer filaments such as the cytoskeleton are the subject of intense research. Oftentimes, mechanics on the scale of single monomers (∼ 5 nm) govern the mechanics of the entire network (∼ 10 μm). Until now, one either resolved the small scales and lost the big (network) picture or focused on mechanics above the single-filament scale and neglected the molecular architecture. Therefore, the study of network mechanics influenced by the entire spectrum of relevant length scales has been infeasible so far. We propose a method that reconciles both small and large length scales without the otherwise inevitable loss in either numerical efficiency or geometrical (molecular) detail. Both explicitly modeled species, filaments and their crosslinkers, are discretized with geometrically exact beam finite elements of Simo-Reissner type. Through specific coupling conditions between the elements of the two species, mechanical joints can be established anywhere along a beam's centerline, enabling arbitrary densities of chemical binding sites. These binding sites can be oriented to model the monomeric architecture of polymers. First, we carefully discuss the method and then demonstrate its capabilities by means of a series of numerical examples.

  11. Solar Space Density of the Red Clump Stars and the Scale-length of the Thin Disc

    CERN Document Server

    Gokce, E Yaz; Duran, S; Bilir, S; Yalcinkaya, A; Ak, S; Ak, T; Lopez-Corredoira, M; Cabrera-Lavers, A

    2015-01-01

    We estimated the scale-length of the thin disc with the J and W1 magnitudes of the most probable Red Clump (RC) stars in the Galactic plane, $-0\\overset{^\\circ}.5 \\leq b \\leq +0\\overset{^\\circ}.5$, in 19 equal sized fields with consecutive Galactic longitudes which cover the interval $90^\\circ \\leq l \\leq 270^\\circ$. Our results are constrained with respect to the solar space density ($D^*=5.95$), which indicates that the radial variation of the density is lower for higher Galactocentric distances. The scale-length of the thin disc is 2 kpc for the fields in the Galactic anticentre direction or close to this direction, while it decreases continuously in the second and third quadrants reaching to a lower limit of $h$ = 1.6 kpc at the Galactic longitudes $l$ = 90$^\\circ$ and $l$ = 270$^\\circ$. The distribution of the scale-length in 19 fields is consistent with the predictions from the Galaxia model and its variation with longitude is probably due to the inhomogeneity structure of the disc caused by the accrete...

  12. Scaling of Teak (Tectona grandis Logs by the Xylometer Technique: Accuracy of Volume Equations and Influence of the Log Length

    Directory of Open Access Journals (Sweden)

    Kouami Kokou

    2013-03-01

    Full Text Available The accuracy of ten methods of scaling (Smalian, Huber, Newton, Neloïd, paraboloid, cone, paracone, cylinder, truncated cone and truncated Neloïd was evaluated on logs of 0.5, 1, 2 and 3 m cut to different heights of 27 teak trees. For this purpose, the volumes estimated by the ten formulas were compared with real volumes obtained by the technique of xylometer. The results obtained showed that the method of Huber was more efficient to calculate the volume of logs throughout the stem when the length was 0.5 m. For the other length logs, it was also the best formula when the logs came from the base of the stem. The formulas of Newton and Smalian gave in the center and top of the stem, in the case of 1 m and 2 m logs, relatively similar results and were better than other methods of scaling. As might be expected, the dendrometric method (cylinder, paraboloid, Neloïd, cone gave worse results regardless of the length of logs considered. With logs of 0.5, 1, 2 and 3 m long, truncated forms of cone and Neloïd could also be used without significant errors in estimating the volume of teak logs. The model scaling obtained for the entire tree expresses the logarithm of the volume against the logarithm of the diameter and the logarithm of height.

  13. Nondriven Polymer Translocation Through a Nanopore:Scaling for Translocation Time with Chain Length

    Institute of Scientific and Technical Information of China (English)

    LI Hui; ZHANG Jing; LIU Hong; SUN Chia-chung

    2011-01-01

    We investigated the dynamics of the passage for a polymer chain through a nanopore in the absence of any external driving force with Weeks-Chandler-Andersen potential in two-dimensional simulations,in particular,focused our attention on the scaling law of the mean translocation time.We found that the effect of hydrodynamic interactions is the major factor in determining the scaling exponents with increasing pore size.The scaling close to N1+2v was observed when the hydrodynamic interactions were screened in the cases of small pore sizes,while the scaling close to N3v was obtained when the hydrodynamic interactions were present in the cases of large pore sizes.

  14. Characteristic of Small Scale Food Industry Cluster in West Sumatera

    Directory of Open Access Journals (Sweden)

    Gunarif Taib

    2014-04-01

    Full Text Available Clusters of small-scale food industries have different characteristics with industrial cluster in general. These characteristics need to know to develop a plan for cluster development. This study was conducted to determine charasteristics clusters of small-scale food industry, especially in West Sumatra. For the analysis of the components of industrial and technological components that affect the development of small-scale food industry cluster in West Sumatra. All variables influence the level of industrial components and technology components were analyzed using the program "Statistical Product and Service Solutions (SPSS". The survey results revealed that the industrial component is influenced by the core industry (level of difficulty in capital gain and raw materials, the buyer (customer satisfaction, related industry (quality and continuity of supply of packaging and institutional support (coaching on marketing and capitalization as well as guidance on the production of sanitary and food safety. Component technology is influenced by organoware (production management and marketing management and humanware (innovation and trust among the members.

  15. Effects of Titanium Oxide Nanotube Arrays with Different Lengths on the Characteristics of Dye-Sensitized Solar Cells

    OpenAIRE

    Chin-Guo Kuo; Cheng-Fu Yang; Lih-Ren Hwang; Jia-Sheng Huang

    2013-01-01

    The self-aligned highly ordered TiO2 nanotube (TNT) arrays were fabricated by potentiostatic anodization of Ti foil, and we found that the TNT-array length and diameter were dependent on the electrolyte (NH4F) concentration in ethylene glycol and anodization time. The characteristics of the fabricated TNT arrays were characterized by XRD pattern, FESEM, and absorption spectrum. As the electrolyte NH4F concentration in the presence of H2O (2 vol%) with anodization was changed from 0.25 to 0.75...

  16. Determination of skin temperature distribution and heat flux during simulated fires using Green's functions over finite-length scales

    International Nuclear Information System (INIS)

    One of the current practices for measuring heat flux during flash fire testing, forest fires, and other industrial cases focuses on the use of semi-infinite models to predict the heat flux during exposure through surface temperature measurements on simulated skin sensors. For short time frames, these models can be shown to have acceptable accuracy. However, when considering longer time exposures at reduced heat fluxes, such as with firefighters in a forest fire, the accuracy of these models could be brought into question. A one-dimensional, finite length scale, transient heat conduction model was developed using a Green's function approach on a rectangular sensor. The model was developed using transient temperature boundary conditions to avoid the use of complicated radiation and convection conditions at each boundary. For comparison, a semi-infinite model utilizing the same boundary condition on the exposed face was solved using both the Laplace transform method and Green's function method. Experimental data was obtained during exposure to a cone calorimeter. All measurements were taken for a minimum duration of 2 min. This temperature data was used to develop appropriate curves for the boundary conditions and validate the analytical models. It was found that the temperature obtained from the one-dimensional transient heat conduction model based on Green's functions agreed well with the experimental results over longer exposure times, and with reduced error when compared with the semi-infinite model. This suggests that modeling the problem on a finite-length scale will produce more accurate or more conservative temperature and heat flux results over extended periods of exposure in high heat load applications. - Highlights: ► Estimation of heat flux and temperature distribution in a body exposed to simulated fire. ► One-dimensional, finite-length scale, transient heat conduction model using a Green's function approach was developed. ► Comparison of

  17. Self-organization on multiple length scales in "hairy rod"-coil block copolymer supramolecular complexes

    OpenAIRE

    Hammond, Matthew R.; Klok, Harm-Anton; Mezzenga, Raffaele

    2008-01-01

    A peptide-synthetic hybrid block copolymer, poly(ethylene oxide)-block-poly(L-glutamic acid), is shown to form supramolecular complexes with primary alkylamines of varying alkyl chain lengths (8 to 18 methylene units) in organic solvents via acid-base proton transfer and subsequent ionic bonding. The peptidic block being in the α-helical conformation, these materials behave as coil-"hairy rod" block copolymers, and show hierarchically self-organized nanostructures in the solid state. X-ray sc...

  18. Study of the overturning length scales at the Spanish planetary boundary layer

    Science.gov (United States)

    López, Pilar; Cano, José L.

    2016-03-01

    The focus of this paper is to analyse the behaviour of the maximum Thorpe displacement (dT)max and the Thorpe scale LT at the atmospheric boundary layer (ABL), extending previous research with new data and improving our studies related to the novel use of the Thorpe method applied to ABL. The maximum Thorpe displacements vary between -900 and 950 m for the different field campaigns. The Thorpe scale LT ranges between 0.2 and 680 m for the different data sets which cover different stratified mixing conditions (turbulence shear-driven and convective regions). We analyse the relationship between (dT)max and the Thorpe scale LT and we deduce that they verify a power law. We also deduce that there is a difference in exponents of the power laws for convective conditions and shear-driven conditions. These different power laws could identify overturns created under different mechanisms.

  19. Parallel Scaling Characteristics of Selected NERSC User ProjectCodes

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, David; Verdier, Francesca; Anand, Harsh; Carter,Jonathan; Durst, Mark; Gerber, Richard

    2005-03-05

    This report documents parallel scaling characteristics of NERSC user project codes between Fiscal Year 2003 and the first half of Fiscal Year 2004 (Oct 2002-March 2004). The codes analyzed cover 60% of all the CPU hours delivered during that time frame on seaborg, a 6080 CPU IBM SP and the largest parallel computer at NERSC. The scale in terms of concurrency and problem size of the workload is analyzed. Drawing on batch queue logs, performance data and feedback from researchers we detail the motivations, benefits, and challenges of implementing highly parallel scientific codes on current NERSC High Performance Computing systems. An evaluation and outlook of the NERSC workload for Allocation Year 2005 is presented.

  20. Characteristics of the east Mediterranean dust variability on small spatial and temporal scales

    Science.gov (United States)

    Yuval; Sorek-Hamer, Meytar; Stupp, Amnon; Alpert, Pinhas; Broday, David M.

    2015-11-01

    The presence of naturally-occurring dust is a conspicuous meteorological phenomenon characterised by very high load of relatively coarse airborne particulate matter (PM), which may contain also various deleterious chemical and biological materials. Much work has been carried out to study the phenomenon by modelling the generation and transport of dust plumes, and assessment of their temporal characteristics on a large (>1000 km) spatial scale. This work studies in high spatial and temporal resolution the characteristics of dust presence on the mesoscale (>100 km). The small scale variability is important both for better understanding the physical characteristics of the dust phenomenon and for PM exposure specification in epidemiological studies. Unsupervised clustering-based method, using PM10 records and their derived attributes, was developed and applied to detect the impact of dust at the observation locations of a PM10 monitoring array. It was found that dust may cover the whole study area but very often the coverage is partial. On average, the larger the spatial extent of a dust event, the higher and more homogeneous are the associated PM10 concentrations. Dust event lengths however, are only weakly associated with the PM concentrations (Pearson correlation below 0.44). The large PM concentration variability during spatially small events and the fact that their occurrence is strongly correlated with the elevation above sea level of the reporting stations (Pearson correlation 0.87, p-value < 10-5) points to small scale spatiotemporal dynamics of dust plumes.

  1. Accurate switching intensities and length scales in quasi-phase-matched materials

    DEFF Research Database (Denmark)

    Bang, Ole; Graversen, Torben Winther; Corney, Joel Frederick

    2001-01-01

    We consider unseeded typeI second-harmonic generation in quasi-phase-matched quadratic nonlinear materials and derive an accurate analytical expression for the evolution of the average intensity. The intensity- dependent nonlinear phase mismatch that is due to the cubic nonlinearity induced by...... quasi phase matching is found. The equivalent formula for the intensity of maximum conversion, the crossing of which changes the one-period nonlinear phase shift of the fundamental abruptly by p , corrects earlier estimates [Opt.Lett. 23, 506 (1998)] by a factor of 5.3. We find the crystal lengths that...... are necessary to obtain an optimal flat phase versus intensity response on either side of this separatrix intensity....

  2. The role of discharge variation in scaling of drainage area and food chain length in rivers

    Science.gov (United States)

    Sabo, John L.; Finlay, Jacques C.; Kennedy, Theodore A.; Post, David M.

    2010-01-01

    Food chain length (FCL) is a fundamental component of food web structure. Studies in a variety of ecosystems suggest that FCL is determined by energy supply, environmental stability, and/or ecosystem size, but the nature of the relationship between environmental stability and FCL, and the mechanism linking ecosystem size to FCL, remain unclear. Here we show that FCL increases with drainage area and decreases with hydrologic variability and intermittency across 36 North American rivers. Our analysis further suggests that hydrologic variability is the mechanism underlying the correlation between ecosystem size and FCL in rivers. Ecosystem size lengthens river food chains by integrating and attenuating discharge variation through stream networks, thereby enhancing environmental stability in larger river systems.

  3. Sensitivity of the two-dimensional shearless mixing layer to the initial turbulent kinetic energy and integral length scale

    Science.gov (United States)

    Fathali, M.; Deshiri, M. Khoshnami

    2016-04-01

    The shearless mixing layer is generated from the interaction of two homogeneous isotropic turbulence (HIT) fields with different integral scales ℓ1 and ℓ2 and different turbulent kinetic energies E1 and E2. In this study, the sensitivity of temporal evolutions of two-dimensional, incompressible shearless mixing layers to the parametric variations of ℓ1/ℓ2 and E1/E2 is investigated. The sensitivity methodology is based on the nonintrusive approach; using direct numerical simulation and generalized polynomial chaos expansion. The analysis is carried out at Reℓ 1=90 for the high-energy HIT region and different integral length scale ratios 1 /4 ≤ℓ1/ℓ2≤4 and turbulent kinetic energy ratios 1 ≤E1/E2≤30 . It is found that the most influential parameter on the variability of the mixing layer evolution is the turbulent kinetic energy while variations of the integral length scale show a negligible influence on the flow field variability. A significant level of anisotropy and intermittency is observed in both large and small scales. In particular, it is found that large scales have higher levels of intermittency and sensitivity to the variations of ℓ1/ℓ2 and E1/E2 compared to the small scales. Reconstructed response surfaces of the flow field intermittency and the turbulent penetration depth show monotonic dependence on ℓ1/ℓ2 and E1/E2 . The mixing layer growth rate and the mixing efficiency both show sensitive dependence on the initial condition parameters. However, the probability density function of these quantities shows relatively small solution variations in response to the variations of the initial condition parameters.

  4. Multi Length Scale Imaging of Flocculated Estuarine Sediments; Insights into their Complex 3D Structure

    Science.gov (United States)

    Wheatland, Jonathan; Bushby, Andy; Droppo, Ian; Carr, Simon; Spencer, Kate

    2015-04-01

    Suspended estuarine sediments form flocs that are compositionally complex, fragile and irregularly shaped. The fate and transport of suspended particulate matter (SPM) is determined by the size, shape, density, porosity and stability of these flocs and prediction of SPM transport requires accurate measurements of these three-dimensional (3D) physical properties. However, the multi-scaled nature of flocs in addition to their fragility makes their characterisation in 3D problematic. Correlative microscopy is a strategy involving the spatial registration of information collected at different scales using several imaging modalities. Previously, conventional optical microscopy (COM) and transmission electron microscopy (TEM) have enabled 2-dimensional (2D) floc characterisation at the gross (> 1 µm) and sub-micron scales respectively. Whilst this has proven insightful there remains a critical spatial and dimensional gap preventing the accurate measurement of geometric properties and an understanding of how structures at different scales are related. Within life sciences volumetric imaging techniques such as 3D micro-computed tomography (3D µCT) and focused ion beam scanning electron microscopy [FIB-SEM (or FIB-tomography)] have been combined to characterise materials at the centimetre to micron scale. Combining these techniques with TEM enables an advanced correlative study, allowing material properties across multiple spatial and dimensional scales to be visualised. The aims of this study are; 1) to formulate an advanced correlative imaging strategy combining 3D µCT, FIB-tomography and TEM; 2) to acquire 3D datasets; 3) to produce a model allowing their co-visualisation; 4) to interpret 3D floc structure. To reduce the chance of structural alterations during analysis samples were first 'fixed' in 2.5% glutaraldehyde/2% formaldehyde before being embedding in Durcupan resin. Intermediate steps were implemented to improve contrast and remove pore water, achieved by the

  5. Scaling and singularity characteristics of solar wind and magnetospheric fluctuations

    Directory of Open Access Journals (Sweden)

    Z. Vörös

    2002-01-01

    Full Text Available Preliminary results are presented which suggest that scaling and singularity characteristics of solar wind and ground-based magnetic fluctuations appear to be a significant component in the solar wind-magnetosphere interaction processes. Of key importance is the intermittence of the "magnetic turbulence" as seen in ground-based and solar wind magnetic data. The methods used in this paper (estimation of flatness and multifractal spectra are commonly used in the studies of fluid or MHD turbulence. The results show that single observatory characteristics of magnetic fluctuations are different from those of the multi-observatory AE-index. In both data sets, however, the influence of the solar wind fluctuations is recognizable. The correlation between the scaling/singularity features of solar wind magnetic fluctuations and the corresponding geomagnetic response is demonstrated in a number of cases. The results are also discussed in terms of patchy reconnection processes in the magnetopause and forced and/or self-organized criticality (F/SOC of internal magnetosphere dynamics.

  6. A validation process for CFD use in building physics – Study of the different length scales

    OpenAIRE

    Barbason, Mathieu; Reiter, Sigrid

    2011-01-01

    Due to growing environmental concerns, Computational Fluid Dynamics (CFD) is more and more used in building physics. Until today, the research community has validated separately several cases but there is no global validation process for this method. The aim of this paper is to provide a way for new users to develop and improve their CFD skills. This paper deals with the different geometry scales involved in building physics. Experimental results are available and will assess the ability of C...

  7. Filtration of precipitated silica aggregates: Length scales, percolation threshold and yielding behaviour

    OpenAIRE

    Ragueh, Deka Moussa; Meireles, Martine; Cabane, Bernard; Gummel, Jérémie

    2015-01-01

    Reinforcing precipitated silica systems have a complex hierarchical structure consisting of a branched network made of connected clusters composed of small silica beads welded together into larger dense aggregates. Here, we study the evolution of such structural features during a filtration process. The typical behaviour is that the cakes formed at constant pressure do not reorganize at local scale during a filtration experiment. Accordingly, the creep resistance of a precipitated silica netw...

  8. Effects of characteristic length scales on the exciton dynamics in rubrene single crystals

    Science.gov (United States)

    Gieseking, Björn; Schmeiler, Teresa; Müller, Benjamin; Deibel, Carsten; Engels, Bernd; Dyakonov, Vladimir; Pflaum, Jens

    2014-11-01

    We present temperature dependent time-resolved photoluminescence (PL) investigations on well-defined morphologies of the prototypical organic semiconductor rubrene. By their respective degree of spatial constraint these morphologies directly influence the temperature dependent excitonic processes and their dynamics. While in bulk single crystals singlet exciton decay is governed by thermally activated fission at a time constant of 20 ps, this mechanism appears to be absent in rubrene microcrystals. Here the dynamics are characterized by a pronounced increase of the average exciton lifetime as confirmed by the dominating PL decay channel with an effective time constant of 100 ps. The enhanced surface-to-volume ratio indicates that the participating states might originate from microcrystal boundaries which could be reached by the substantial amount of migrating excitons prior to the onset of other decay processes. The suppression of singlet fission in these crystalline microstructures is promoted by the significantly lower activation energy of 25 meV for the 100 ps channel compared to the singlet fission barrier of 44 meV and imposes severe consequences for its utilization in, e.g., thin film photovoltaics. For the crystalline samples, an additional relaxation channel with a time constant of around 500 ps becomes relevant at very low temperatures. As this process is the only one observed for amorphous rubrene thin films it points at the local nature of the underlying decay mechanism.

  9. Fine-scale local adaptation of weevil mouthpart length and camellia pericarp thickness: altitudinal gradient of a putative arms race.

    Science.gov (United States)

    Toju, Hirokazu

    2008-05-01

    Although coevolutionary theory predicts that evolutionary interactions between species are spatially hierarchical, few studies have examined coevolutionary processes at multiple spatial scales. In an antagonistic system involving a plant, the Japanese camellia (Camellia japonica), and its obligate seed predator, the camellia weevil (Curculio camelliae), I elucidated the local adaptation of a camellia defensive armament (pericarp thickness) and a weevil offensive armament (rostrum length) within Yakushima Island (ca. 30 km in diameter), compared to a larger-scale variation in those traits throughout Japan reported in previous studies. Results showed that camellia pericarp thickness and weevil rostrum length vary remarkably within several kilometers on this island. In addition, geographic variation in each camellia and weevil armament was best explained by the armament size of the sympatric participant than by abiotic environmental heterogeneity. However, I also found that camellia pericarp thickness significantly decreased in cool-temperate (i.e., highland) areas, suggesting the contributions of climate on the spatial structuring of the weevil-camellia interaction. Interestingly, relatively thin pericarps occurred not only in the highlands but also in some low-altitude areas, indicating that other factors such as nonrandom or asymmetric gene flow play important roles in the metapopulation processes of interspecific interactions at small spatial scales. PMID:18266990

  10. Observation of the Degradation Characteristics and Scale of Unevenness on Three-dimensional Artificial Rock Joint Surfaces Subjected to Shear

    Science.gov (United States)

    Hong, Eun-Soo; Kwon, Tae-Hyuk; Song, Ki-Il; Cho, Gye-Chun

    2016-01-01

    The present study explores the degradation characteristics and scale of unevenness (small-scale roughness) on sheared rock joint surfaces at a low-stress regime. While the degradation characteristics of unevenness and the normal stress are mutually interrelated, an understanding of the degradation patterns of the three-dimensional roughness of rock joints is one of the important components needed to identify asperity failure characteristics and to quantify the role of damaged unevenness in establishing a shear strength model. A series of direct shear tests was performed on three-dimensional artificial rock joint surfaces at different normal stress levels. After shearing, the spatial distributions and statistical parameters of degraded roughness were analysed for the different normal stress levels. The length and area of the degraded zones showed bell-shaped distributions in a logarithmic scale, and the dominant scale (or the most frequently occurring scale) of the damaged asperities (i.e., unevenness) ranged from approximately, 0.5 to 5.0 mm in length and 0.1-10 mm2 in area. This scale of the damaged unevenness was consistent regardless of the level of normal stress. It was also found that the relative area of damaged unevenness on a given joint area, and thus the contribution of the mechanical asperity failure component to shear strength increased as normal stress increased.

  11. Length distributions of identity by descent reveal fine-scale demographic history.

    Science.gov (United States)

    Palamara, Pier Francesco; Lencz, Todd; Darvasi, Ariel; Pe'er, Itsik

    2012-11-01

    Data-driven studies of identity by descent (IBD) were recently enabled by high-resolution genomic data from large cohorts and scalable algorithms for IBD detection. Yet, haplotype sharing currently represents an underutilized source of information for population-genetics research. We present analytical results on the relationship between haplotype sharing across purportedly unrelated individuals and a population's demographic history. We express the distribution of IBD sharing across pairs of individuals for segments of arbitrary length as a function of the population's demography, and we derive an inference procedure to reconstruct such demographic history. The accuracy of the proposed reconstruction methodology was extensively tested on simulated data. We applied this methodology to two densely typed data sets: 500 Ashkenazi Jewish (AJ) individuals and 56 Kenyan Maasai (MKK) individuals (HapMap 3 data set). Reconstructing the demographic history of the AJ cohort, we recovered two subsequent population expansions, separated by a severe founder event, consistent with previous analysis of lower-throughput genetic data and historical accounts of AJ history. In the MKK cohort, high levels of cryptic relatedness were detected. The spectrum of IBD sharing is consistent with a demographic model in which several small-sized demes intermix through high migration rates and result in enrichment of shared long-range haplotypes. This scenario of historically structured demographies might explain the unexpected abundance of runs of homozygosity within several populations. PMID:23103233

  12. Optimal smoothing length scale for actuator line models of lifting surfaces

    CERN Document Server

    Martinez-Tossas, Luis A

    2015-01-01

    The actuator line model (ALM) is a commonly used method to represent lifting surfaces such as wind turbine blades within Large-Eddy Simulations (LES). In ALM the lift and drag forces are replaced by an imposed body force which is typically smoothed over several grid points using a Gaussian kernel with some prescribed smoothing width $\\epsilon$. To date, the choice of $\\epsilon$ has most often been based on numerical considerations mostly related to the grid spacing used in LES. However, especially for finely resolved LES with grid spacings on the order or smaller than the chord-length of the blade, the best choice of $\\epsilon$ is not known. Focusing first on the lift force, here we find $\\epsilon$ and the force center location that minimize the square difference between the velocity fields obtained from solving 2D potential flow over Joukowski airfoils and solving the Euler equations including the imposed body force. The latter solution is found for the linearized problem, and is valid for small angles of at...

  13. Search for Screened Interactions Below the Dark Energy Length Scale Using Optically Levitated Microspheres

    CERN Document Server

    Rider, Alexander D; Blakemore, Charles P; Louis, Maxime; Lu, Marie; Gratta, Giorgio

    2016-01-01

    We present the results of a search for unknown interactions that couple to mass between an optically levitated microsphere and a gold-coated silicon cantilever. The scale and geometry of the apparatus enables a search for new forces that appear at distances below 100 $\\mu$m and which would have evaded previous searches due to screening mechanisms. The data are consistent with electrostatic backgrounds and place upper limits on the strength of new interactions at 5.6 \\times 10^4$ in the region of parameter space where the self-coupling $\\Lambda \\gtrsim 5$ meV and the microspheres are not fully screened.

  14. Evidence of two-length-scale kinetics of R-phase transformation by high-energy X-ray diffraction

    International Nuclear Information System (INIS)

    The cubic-to-rhombohedral (C-R) phase transition in an AuCd shape memory alloy was investigated by in situ high-energy X-ray diffraction. We present the first direct experimental evidence of two-length-scale phase transition kinetics in this alloy system. It was further found that aging in the R-phase leads to two-way memory 'loss', characterized by the reselection of new variants. We attributed this two-way memory 'loss' to the internal stresses caused by the defects formed in the off-equilibrium state of the studied AuCd system.

  15. PIV measurements of the turbulence integral length scale on cold combustion flow field of tangential firing boiler

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wen-fei; Xie, Jing-xing; Gong, Zhi-jun; Li, Bao-wei [Inner Mongolia Univ. of Science and Technology, Baotou (China). Inner Mongolia Key Lab. for Utilization of Bayan Obo Multi-Metallic Resources: Elected State Key Lab.

    2013-07-01

    The process of the pulverized coal combustion in tangential firing boiler has prominent significance on improving boiler operation efficiency and reducing NO{sub X} emission. This paper aims at researching complex turbulent vortex coherent structure formed by the four corners jets in the burner zone, a cold experimental model of tangential firing boiler has been built. And by employing spatial correlation analysis method and PIV (Particle Image Velocimetry) technique, the law of Vortex scale distribution on the three typical horizontal layers of the model based on the turbulent Integral Length Scale (ILS) has been researched. According to the correlation analysis of ILS and the temporal average velocity, it can be seen that the turbulent vortex scale distribution in the burner zone of the model is affected by both jet velocity and the position of wind layers, and is not linear with the variation of jet velocity. The vortex scale distribution of the upper primary air is significantly different from the others. Therefore, studying the ILS of turbulent vortex integral scale is instructive to high efficiency cleaning combustion of pulverized coal in theory.

  16. High Temperature Thermoelectric Oxides Engineered At Multiple Length Scales For Energy Harvesting

    Energy Technology Data Exchange (ETDEWEB)

    Ohuchi, Fumio [Univ. of Washington, Seattle, WA (United States); Bordia, Rajendra [Clemson Univ., SC (United States)

    2014-12-20

    Thermoelectric aspects of the processing parameters the n-type relaxors, including SrxBa1-xNb2O6 (SBN100x), Sr2Nb2O7 (SN) and SrBi2Nb2O9 (SBiN), were investigated. A solution combustion synthesis (SCS) route was devised to fabricate SBN, SN and SBiN nanoparticles with excellent phase purity. X-ray photoelectron spectroscopy (XPS) was used to deduce the local cation site occupancy, and detailed thermoelectric transport processes were investigated. Based on the identified behavior, effectiveness of pore formers on the thermoelectric performance was investigated with the goal of decreasing κ through enhanced phonon scattering while preserving the electron transport characteristics.

  17. Study on the primary characteristics of identifi cation: estimation of stature from palm length among the native Guajarati population

    Directory of Open Access Journals (Sweden)

    Aneri Choksi

    2014-07-01

    Full Text Available Criminal investigation always involves the identification of individuals involved in any incidence that is under question. Identification of individual is based on the available physical evidences. The most conventional method of identification of individuals is based on the fingerprints. There are certain instances wherein the identity of individual would be done based on certain anthropometric data such as measurements of various body parts although the complete identification is possible with fingerprints, DNA and patterns still the primary characteristic of identification such as stature and sex can be determined. In this study, an attempt has been made to establish the possible correlation between the palm length with the stature of individual. To get scrupulous results, the study has been done on the young adult population in the age range of 21-25 years. A total number of 500 subjects were considered for the study that includes 200 boys and 300 girls. Significant results were obtained. It was possible to deduce the correlation coefficient and multiplication factor for estimation of stature from palm length. The multiplication factor so deduced has been applied and regression analysis was done and was found to be significant and reliable .

  18. Molecular density functional theory of water describing hydrophobicity at short and long length scales

    Science.gov (United States)

    Jeanmairet, Guillaume; Levesque, Maximilien; Borgis, Daniel

    2013-10-01

    We present an extension of our recently introduced molecular density functional theory of water [G. Jeanmairet et al., J. Phys. Chem. Lett. 4, 619 (2013)] to the solvation of hydrophobic solutes of various sizes, going from angstroms to nanometers. The theory is based on the quadratic expansion of the excess free energy in terms of two classical density fields: the particle density and the multipolar polarization density. Its implementation requires as input a molecular model of water and three measurable bulk properties, namely, the structure factor and the k-dependent longitudinal and transverse dielectric susceptibilities. The fine three-dimensional water structure around small hydrophobic molecules is found to be well reproduced. In contrast, the computed solvation free-energies appear overestimated and do not exhibit the correct qualitative behavior when the hydrophobic solute is grown in size. These shortcomings are corrected, in the spirit of the Lum-Chandler-Weeks theory, by complementing the functional with a truncated hard-sphere functional acting beyond quadratic order in density, and making the resulting functional compatible with the Van-der-Waals theory of liquid-vapor coexistence at long range. Compared to available molecular simulations, the approach yields reasonable solvation structure and free energy of hard or soft spheres of increasing size, with a correct qualitative transition from a volume-driven to a surface-driven regime at the nanometer scale.

  19. Eddy length scales and the Rossby radius in the Arctic Ocean

    Directory of Open Access Journals (Sweden)

    A. J. G. Nurser

    2013-10-01

    Full Text Available The first (and second baroclinic deformation (or Rossby radii are presented and discussed north of ~60° N, focusing on deep basins and shelf seas in the high Arctic Ocean, the Nordic Seas, Baffin Bay, Hudson Bay and the Canadian Arctic Archipelago, derived from high-resolution ice-ocean general circulation model output. Comparison of the model output with measured results shows that low values of the Rossby radius (in shallow water and high values (in the Canada Basin are accurately reproduced, while intermediate values (in the region of the Makarov and Amundsen Basins are overestimated. In the high Arctic Ocean, the first Rossby radius increases from ~5 km in the Nansen Basin to ~15 km in the central Canadian Basin. In the shelf seas and elsewhere, values are low (1–7 km, reflecting weak density stratification, shallow water, or both. Seasonality only strongly impacts the Rossby radii in shallow seas where winter homogenisation of the water column can reduce it to the order of 100 m. We also offer an interpretation and explanation of the observed scales of Arctic Ocean eddies.

  20. The stellar velocity dispersion in the inner 1.3 disk scale-lengths of the irregular galaxy NGC 4449

    CERN Document Server

    Hunter, D A; Swaters, R A; Sparke, L S; Levine, S E; Hunter, Deidre A.; Rubin, Vera C.; Swaters, Rob A.; Sparke, Linda S.; Levine, Stephen E.

    2005-01-01

    We present measurements of the stellar velocity dispersion in the inner 1 arcmin radius (1.3 disk scale-lengths) of the irregular galaxy NGC 4449 determined from long-slit absorption-line spectra. The average observed dispersion is 29 +/-2 km/s, the same as predicted from NGC 4449's luminosity. No significant rotation in the stars is detected. If we assume a maximum rotation speed of the stars from the model determined from the gas kinematics of Hunter et al. (2002), the ratio V_max/sigma_z measured globally is 3. This ratio is comparable to values measured in spiral galaxies, and implies that the stellar disk in NGC 4449 is kinematically relatively cold. The intrinsic minor-to-major axis ratio (b/a)_0 is predicted to be in the range 0.3-0.6, similar to values derived from the distribution of observed b/a of Im galaxies. However, V/sigma_z measured locally is 0.5-1.1, and so the circular velocity of NGC 4449 is comparable or less than the velocity of the stars within the central 1.3 disk scale-lengths of the ...

  1. Age-related changes in the plasticity and toughness of human cortical bone at multiple length-scales

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, Elizabeth A.; Schaible, Eric; Bale, Hrishikesh; Barth, Holly D.; Tang, Simon Y.; Reichert, Peter; Busse, Bjoern; Alliston, Tamara; Ager III, Joel W.; Ritchie, Robert O.

    2011-08-10

    The structure of human cortical bone evolves over multiple length-scales from its basic constituents of collagen and hydroxyapatite at the nanoscale to osteonal structures at nearmillimeter dimensions, which all provide the basis for its mechanical properties. To resist fracture, bone’s toughness is derived intrinsically through plasticity (e.g., fibrillar sliding) at structural-scales typically below a micron and extrinsically (i.e., during crack growth) through mechanisms (e.g., crack deflection/bridging) generated at larger structural-scales. Biological factors such as aging lead to a markedly increased fracture risk, which is often associated with an age-related loss in bone mass (bone quantity). However, we find that age-related structural changes can significantly degrade the fracture resistance (bone quality) over multiple lengthscales. Using in situ small-/wide-angle x-ray scattering/diffraction to characterize sub-micron structural changes and synchrotron x-ray computed tomography and in situ fracture-toughness measurements in the scanning electron microscope to characterize effects at micron-scales, we show how these age-related structural changes at differing size-scales degrade both the intrinsic and extrinsic toughness of bone. Specifically, we attribute the loss in toughness to increased non-enzymatic collagen cross-linking which suppresses plasticity at nanoscale dimensions and to an increased osteonal density which limits the potency of crack-bridging mechanisms at micron-scales. The link between these processes is that the increased stiffness of the cross-linked collagen requires energy to be absorbed by “plastic” deformation at higher structural levels, which occurs by the process of microcracking.

  2. Statistical investigation of the length-dependent deviations in the electrical characteristics of molecular electronic junctions fabricated using the direct metal transfer method

    Science.gov (United States)

    Jeong, Hyunhak; Kim, Dongku; Kwon, Hyukwoo; Hwang, Wang-Taek; Jang, Yeonsik; Min, Misook; Char, Kookrin; Xiang, Dong; Jeong, Heejun; Lee, Takhee

    2016-03-01

    We fabricated and analyzed the electrical transport characteristics of vertical type alkanethiolate molecular junctions using the high-yield fabrication method that we previously reported. The electrical characteristics of the molecular electronic junctions were statistically collected and investigated in terms of current density and transport parameters based on the Simmons tunneling model, and we determined representative current-voltage characteristics of the molecular junctions. In particular, we examined the statistical variations in the length-dependent electrical characteristics, especially the Gaussian standard deviation σ of the current density histogram. From the results, we found that the magnitude of the σ value can be dependent on the individual molecular length due to specific microscopic structures in the molecular junctions. The probable origin of the molecular length-dependent deviation of the electrical characteristics is discussed.

  3. Statistical investigation of the length-dependent deviations in the electrical characteristics of molecular electronic junctions fabricated using the direct metal transfer method

    International Nuclear Information System (INIS)

    We fabricated and analyzed the electrical transport characteristics of vertical type alkanethiolate molecular junctions using the high-yield fabrication method that we previously reported. The electrical characteristics of the molecular electronic junctions were statistically collected and investigated in terms of current density and transport parameters based on the Simmons tunneling model, and we determined representative current–voltage characteristics of the molecular junctions. In particular, we examined the statistical variations in the length-dependent electrical characteristics, especially the Gaussian standard deviation σ of the current density histogram. From the results, we found that the magnitude of the σ value can be dependent on the individual molecular length due to specific microscopic structures in the molecular junctions. The probable origin of the molecular length-dependent deviation of the electrical characteristics is discussed. (paper)

  4. Nontrivial correlation length distinguishes melt from glass in a large-scale atomistic non-equilibrium simulation of a glass transition

    Science.gov (United States)

    Mandadapu, Kranthi; Hudson, Alexander; Chandler, David

    2015-03-01

    Dynamical facilitation theory predicts the emergence of a non-trivial correlation length from the cooling process that transforms the reversible melt to the irreversible glass. A decrease in cooling rate produces an increase in correlation length, and an increase in correlation length coincides with an increase in stability and aging rate of the glass. Here, we present results from a large-scale non-equilibrium numerical simulation that provide the first demonstration of the emergent nonequilbrium correlation length for an atomistic model. The study also tests the ability of the theory to predict the value of the nonequilibrium length and its corresponding glass transition temperature in terms of material properties and cooling protocols. Nontrivial correlation length distinguishes melt from glass in a large-scale atomistic non-equilibrium simulation of a glass transition

  5. Millennial-scale characteristics of the geomagnetic field

    International Nuclear Information System (INIS)

    Complete text of publication follows. A new series of continuous global magnetic field models has recently been developed spanning the past 3000 years, based on several subsets of available archeo- and paleomagnetic data. These and our previous CALS7K.2 model are used to investigate the evolution of various field characteristics and assess their robustness in the different models. The spatial resolution achievable for global models with the number and quality of data presently available lies in the order of spherical harmonic degree 4. Differences among the millennial scale field models partly reflect the uncertainties in the models, but can also be significantly influenced by variations in data distributions. This is especially true for models based only on archeomagnetic data, as to date very few of these data come from the southern hemisphere and the global distribution is strongly biased towards Europe. For example, even in the dipole tilt with respect to the rotation axis significant differences are seen between models that include magnetic information from sediment records and those that do not. We argue that field variations seen in the archeomagnetic data that seem to be accommodated by stronger tilt of the dipole reflect a strong bias in the associated data distribution. These stronger tilts are incompatible with the information from several sediment records, particularly those from the southern hemisphere. Models based on all available data suggest that on average the dipole tilt over the past few millennia was lower than today. Recent and historical models show two pairs of distinct magnetic flux lobes in the northern and southern hemisphere field at the core-mantle boundary and a growing patch of reversed flux in the southern hemisphere, causing the so-called South Atlantic Anomaly. Time averages of the 3 ka models suggest a preference for a similar flux lobe configuration and the possibility of an intensity minimum in the South Atlantic region

  6. Relative strength of second harmonic and 3/2 omega emissions from long-scale-length laser produced plasmas

    International Nuclear Information System (INIS)

    Experiments were conducted on the planar slab targets of carbon, aluminum, and copper, using a 1.0641 μm laser, at laser intensities varying from 2 x 10/sup 12/ to 1 x 10/sup 14/ W/cm/sup 2/. The laser had a fluorescent linewidth of 4.5 A. Spectral profiles of parametrically modulated second harmonic as well as 3/2/ω/sub 0/ emissions have been measured for the long-scale-length plasmas so generated. Relative strengths of three emissions with respect to peak signal intensity and spectral energy content as a function of laser intensity are graphically reported. Results are discussed on the basis of two plasmon and parametric decay instabilities

  7. Influence of Growth Rate on Microstructural Length Scales in Directionally Solidified NiAl-Mo Hypo-Eutectic Alloy

    Science.gov (United States)

    Zhang, Jianfei; Ma, Xuewei; Ren, Huiping; Chen, Lin; Jin, Zili; Li, Zhenliang; Shen, Jun

    2016-01-01

    In this article, the Ni-46.1Al-7.8Mo (at.%) alloy was directionally solidified at different growth rates ranging from 15 μm/s to 1000 μm/s under a constant temperature gradient (334 K/cm). The dependence of microstructural length scales on the growth rate was investigated. The results show that, with the growth rate increasing, the primary dendritic arm spacings (PDAS) and secondary dendritic arm spacings (SDAS) decreased. There exists a large distribution range in PDAS under directional solidification conditions at a constant temperature gradient. The average PDAS and SDAS as a function of growth rate can be given as λ1 = 848.8967 V-0.4509 and λ2 = 64.2196 V-0.4140, respectively. In addition, a comparison of our results with the current theoretical models and previous experimental results has also been made.

  8. Load partitioning between the bcc-iron matrix and NiAl-type precipitates in a ferritic alloy on multiple length scales

    Science.gov (United States)

    Sun, Zhiqian; Song, Gian; Sisneros, Thomas A.; Clausen, Bjørn; Pu, Chao; Li, Lin; Gao, Yanfei; Liaw, Peter K.

    2016-01-01

    An understanding of load sharing among constituent phases aids in designing mechanical properties of multiphase materials. Here we investigate load partitioning between the body-centered-cubic iron matrix and NiAl-type precipitates in a ferritic alloy during uniaxial tensile tests at 364 and 506 °C on multiple length scales by in situ neutron diffraction and crystal plasticity finite element modeling. Our findings show that the macroscopic load-transfer efficiency is not as high as that predicted by the Eshelby model; moreover, it depends on the matrix strain-hardening behavior. We explain the grain-level anisotropic load-partitioning behavior by considering the plastic anisotropy of the matrix and elastic anisotropy of precipitates. We further demonstrate that the partitioned load on NiAl-type precipitates relaxes at 506 °C, most likely through thermally-activated dislocation rearrangement on the microscopic scale. The study contributes to further understanding of load-partitioning characteristics in multiphase materials. PMID:26979660

  9. Allometric and temporal scaling of movement characteristics in Galapagos tortoises.

    Science.gov (United States)

    Bastille-Rousseau, Guillaume; Yackulic, Charles B; Frair, Jacqueline L; Cabrera, Freddy; Blake, Stephen

    2016-09-01

    Understanding how individual movement scales with body size is of fundamental importance in predicting ecological relationships for diverse species. One-dimensional movement metrics scale consistently with body size yet vary over different temporal scales. Knowing how temporal scale influences the relationship between animal body size and movement would better inform hypotheses about the efficiency of foraging behaviour, the ontogeny of energy budgets, and numerous life-history trade-offs. We investigated how the temporal scaling of allometric patterns in movement varies over the course of a year, specifically during periods of motivated (directional and fast movement) and unmotivated (stationary and tortuous movement) behaviour. We focused on a recently diverged group of species that displays wide variation in movement behaviour - giant Galapagos tortoises (Chelonoidis spp.) - to test how movement metrics estimated on a monthly basis scaled with body size. We used state-space modelling to estimate seven different movement metrics of Galapagos tortoises. We used log-log regression of the power law to evaluate allometric scaling for these movement metrics and contrasted relationships by species and sex. Allometric scaling of movement was more apparent during motivated periods of movement. During this period, allometry was revealed at multiple temporal intervals (hourly, daily and monthly), with values observed at daily and monthly intervals corresponding most closely to the expected one-fourth scaling coefficient, albeit with wide credible intervals. We further detected differences in the magnitude of scaling among taxa uncoupled from observed differences in the temporal structuring of their movement rates. Our results indicate that the definition of temporal scales is fundamental to the detection of allometry of movement and should be given more attention in movement studies. Our approach not only provides new conceptual insights into temporal attributes in one

  10. A characteristic scale in radiation fields of fractal clouds

    Energy Technology Data Exchange (ETDEWEB)

    Wiscombe, W.; Cahalan, R.; Davis, A.; Marshak, A. [Goddard Space Flight Center, Greenbelt, MD (United States)

    1996-04-01

    The wavenumber spectrum of Landsat imagery for marine stratocumulus cloud shows a scale break when plotted on a double log plot. We offer an explanation of this scale break in terms of smoothing by horizontal radiative fluxes, which is parameterized and incorporated into an improved pixel approximation. We compute the radiation fields emerging from cloud models with horizontally variable optical depth fractal models. We use comparative spectral and multifractal analysis to qualify the validity of the independent pixel approximation at the largest scales and demonstrate it`s shortcomings on the smallest scales.

  11. Seeing with the nano-eye: accessing structure, function, and dynamics of matter on its natural length and time scales

    Science.gov (United States)

    Raschke, Markus

    2015-03-01

    To understand and ultimately control the properties of most functional materials, from molecular soft-matter to quantum materials, requires access to the structure, coupling, and dynamics on the elementary time and length scales that define the microscopic interactions in these materials. To gain the desired nanometer spatial resolution with simultaneous spectroscopic specificity we combine scanning probe microscopy with different optical, including coherent, nonlinear, and ultrafast spectroscopies. The underlying near-field interaction mediated by the atomic-force or scanning tunneling microscope tip provides the desired deep-sub wavelength nano-focusing enabling few-nm spatial resolution. I will introduce our generalization of the approach in terms of the near-field impedance matching to a quantum system based on special optical antenna-tip designs. The resulting enhanced and qualitatively new forms of light-matter interaction enable measurements of quantum dynamics in an interacting environment or to image the electromagnetic local density of states of thermal radiation. Other applications include the inter-molecular coupling and dynamics in soft-matter hetero-structures, surface plasmon interferometry as a probe of electronic structure and dynamics in graphene, and quantum phase transitions in correlated electron materials. These examples highlight the general applicability of the new near-field microscopy approach, complementing emergent X-ray and electron imaging tools, aiming towards the ultimate goal of probing matter on its most elementary spatio-temporal level.

  12. Study of instabilities in long scale-length plasmas with and without laser-beam-smoothing techniques

    International Nuclear Information System (INIS)

    Experimental results are presented for the interaction of an intense laser beam in large preformed, homogeneous underdense plasmas. Parametric instabilities, including filamentation, stimulated Raman (SRS) and stimulated Brillouin scattering (SBS), have been extensively studied. In this paper comparisons are made between coherent and smoothed laser interaction beams for their effectiveness in suppressing these instabilities. Direct observations of the enhanced breakup of the coherent interaction beam due to filamentation are presented. Measurements of the transverse scale lengths of the hot spots, and the level of the intensity modulations of the filamentary structures are given. Further, direct experimental observations of SRS and SBS generated in filaments are presented. These provided conclusive evidence that this instability provides the primary mechanism for the generation of SRS and SBS under such plasma conditions. With the smoothed laser interaction beams, using random phase plates (RPP) and induced spatial incoherence (ISI), the level of filamention was significantly reduced. The backscattered fractions of SRS and SBS with respect to the irradiance of the interaction beam were measured for coherent, RPP and ISI. Reduction of typically a factor of 20 and 500 were recorded using RPP and ISI, respectively, in the backscattering levels of SRS and SBS when compared with the coherent interaction beam. The reductions are attributed primarily to the effectiveness of the beam-smoothing techniques in suppressing the filamentation instability

  13. The seasonal and solar cycle variations of electron density gradient scale length during magnetically disturbed days: implications for Spread F

    Science.gov (United States)

    Manju, G.; Devasia, C. V.; Ravindran, S.

    2009-07-01

    The behaviour of electron density gradient scale length, L, around post-sunset hours during the magnetically disturbed days of the summer, winter and equinox seasons of solar maximum (2002) and minimum years (1995) has been studied, using ionosonde data of Trivandrum (8.5°N, 76.5°E, dip = 0.5°N) in the Indian longitude sector. The results indicate a clear seasonal and solar cycle variation in L. Seasonal variations of the maximum vertical drift of the F layer were also examined on these days. In particular, the seasonal variation of the Equatorial Spread F (ESF) during this period is examined in terms of the relative roles of L and the vertical drift of the F layer in the triggering of the collisional Rayleigh-Taylor instability. Our results on the clear-cut seasonal and solar cycle variation in L for disturbed days and its control of ESF occurrence are presented and discussed.

  14. Contact damage and fracture micromechanisms of multilayered TiN/CrN coatings at micro- and nano-length scales

    International Nuclear Information System (INIS)

    In this study, systematic nanomechanical and micromechanical studies have been conducted in three multilayer TiN/CrN systems with different bilayer periods (8, 19 and 25 nm). Additionally, experimental work has been performed on corresponding TiN and CrN single layers, for comparison purposes. The investigation includes the use of different indenter tip geometries as well as contact loading conditions (i.e. indentation/scratch) such to induce different stress field and damage scenarios within the films. The surface and subsurface damage under the different indentation imprints and scratch tracks have been observed by atomic force microscopy, field emission scanning electron microscopy and focused ion beam. Multilayer TiN/CrN coated systems are found to exhibit higher adhesion strength (under sliding contact load) and cracking resistance (under spherical indentation) than those coated with reference TiN and CrN monolayers. The main reason behind these findings is the effective development of microstructurally-driven deformation and cracking resistant micromechanisms: rotation of columnar grains (and associated distortion of bilayer period) and crack deflection of interlayer thickness length scale, respectively. - Highlights: • Nanomechanical and micromechanical study in TiN/CrN systems • TiN/CrN coated systems exhibit higher adhesion strength and cracking resistance. • Main deformation and cracking micromechanisms: columnar grain rotation and crack deflection

  15. Global-scale pattern of peatland Sphagnum growth driven by photosynthetically active radiation and growing season length

    Directory of Open Access Journals (Sweden)

    Z. Yu

    2012-02-01

    Full Text Available High-latitude peatlands contain about one third of the world's soil organic carbon, most of which is derived from partly decomposed Sphagnum (peat moss plants. We conducted a meta-analysis based on a global dataset of Sphagnum growth measurements collected from published literature to investigate the effects of bioclimatic variables on Sphagnum growth. Analysis of variance and general linear models were used to relate Sphagnum magellanicum and S. fuscum growth rates to photosynthetically active radiation integrated over the growing season (PAR0 and a moisture index. We found that PAR0 was the main predictor of Sphagnum growth for the global dataset, and effective moisture was only correlated with moss growth at continental sites. The strong correlation between Sphagnum growth and PAR0 suggests the existence of a global pattern of growth, with slow rates under cool climate and short growing seasons, highlighting the important role of temperature and growing season length in explaining peatland biomass production. Large-scale patterns of cloudiness during the growing season might also limit moss growth. Although considerable uncertainty remains over the carbon balance of peatlands under a changing climate, our results suggest that increasing PAR0 as a result of global warming and lengthening growing seasons could promote Sphagnum growth. Assuming that production and decomposition have the same sensitivity to temperature, this enhanced growth could lead to greater peat-carbon sequestration, inducing a negative feedback to climate change.

  16. Global-scale pattern of peatland Sphagnum growth driven by photosynthetically active radiation and growing season length

    Directory of Open Access Journals (Sweden)

    Z. Yu

    2012-07-01

    Full Text Available High-latitude peatlands contain about one third of the world's soil organic carbon, most of which is derived from partly decomposed Sphagnum (peat moss plants. We conducted a meta-analysis based on a global data set of Sphagnum growth measurements collected from published literature to investigate the effects of bioclimatic variables on Sphagnum growth. Analysis of variance and general linear models were used to relate Sphagnum magellanicum and S. fuscum growth rates to photosynthetically active radiation integrated over the growing season (PAR0 and a moisture index. We found that PAR0 was the main predictor of Sphagnum growth for the global data set, and effective moisture was only correlated with moss growth at continental sites. The strong correlation between Sphagnum growth and PAR0 suggests the existence of a global pattern of growth, with slow rates under cool climate and short growing seasons, highlighting the important role of growing season length in explaining peatland biomass production. Large-scale patterns of cloudiness during the growing season might also limit moss growth. Although considerable uncertainty remains over the carbon balance of peatlands under a changing climate, our results suggest that increasing PAR0 as a result of global warming and lengthening growing seasons, without major change in cloudiness, could promote Sphagnum growth. Assuming that production and decomposition have the same sensitivity to temperature, this enhanced growth could lead to greater peat-carbon sequestration, inducing a negative feedback to climate change.

  17. Imaging of Acoustically Coupled Oscillations Due to Flow Past a Shallow Cavity: Effect of Cavity Length Scale

    Energy Technology Data Exchange (ETDEWEB)

    P. Oshkai; M. Geveci; D. Rockwell; M. Pollack

    2002-12-12

    Flow-acoustic interactions due to fully turbulent inflow past a shallow axisymmetric cavity mounted in a pipe are investigated using a technique of high-image-density particle image velocimetry in conjunction with unsteady pressure measurements. This imaging leads to patterns of velocity, vorticity, streamline topology, and hydrodynamic contributions to the acoustic power integral. Global instantaneous images, as well as time-averaged images, are evaluated to provide insight into the flow physics during tone generation. Emphasis is on the manner in which the streamwise length scale of the cavity alters the major features of the flow structure. These image-based approaches allow identification of regions of the unsteady shear layer that contribute to the instantaneous hydrodynamic component of the acoustic power, which is necessary to maintain a flow tone. In addition, combined image analysis and pressure measurements allow categorization of the instantaneous flow patterns that are associated with types of time traces and spectra of the fluctuating pressure. In contrast to consideration based solely on pressure spectra, it is demonstrated that locked-on tones may actually exhibit intermittent, non-phase-locked images, apparently due to low damping of the acoustic resonator. Locked-on flow tones (without modulation or intermittency), locked-on flow tones with modulation, and non-locked-on oscillations with short-term, highly coherent fluctuations are defined and represented by selected cases. Depending on which of,these regimes occur, the time-averaged Q (quality)-factor and the dimensionless peak pressure are substantially altered.

  18. Contact damage and fracture micromechanisms of multilayered TiN/CrN coatings at micro- and nano-length scales

    Energy Technology Data Exchange (ETDEWEB)

    Roa, J.J., E-mail: joan.josep.roa@upc.edu [CIEFMA — Departament de Ciència dels Materials i Eng. Metallúrgica, Universitat Politècnica de Catalunya, Avda. Diagonal 647, 08028 Barcelona (Spain); CRnE, Universitat Politècnica de Catalunya, C. Pasqual i Vila 15, 08028 Barcelona (Spain); Jiménez-Piqué, E. [CIEFMA — Departament de Ciència dels Materials i Eng. Metallúrgica, Universitat Politècnica de Catalunya, Avda. Diagonal 647, 08028 Barcelona (Spain); CRnE, Universitat Politècnica de Catalunya, C. Pasqual i Vila 15, 08028 Barcelona (Spain); Martínez, R. [Centro de Ingeniería Avanzada de Superfícies, Asociación de la Industria Navarra — AIN, Crta. Pamplona, 1, Edificio AIN, 31191 Cordovilla (Spain); Ramírez, G. [CIEFMA — Departament de Ciència dels Materials i Eng. Metallúrgica, Universitat Politècnica de Catalunya, Avda. Diagonal 647, 08028 Barcelona (Spain); Fundació CTM Centre Tecnològic, Avda. Bases de Manresa 1, 08243 Manresa (Spain); Tarragó, J.M. [CIEFMA — Departament de Ciència dels Materials i Eng. Metallúrgica, Universitat Politècnica de Catalunya, Avda. Diagonal 647, 08028 Barcelona (Spain); CRnE, Universitat Politècnica de Catalunya, C. Pasqual i Vila 15, 08028 Barcelona (Spain); and others

    2014-11-28

    In this study, systematic nanomechanical and micromechanical studies have been conducted in three multilayer TiN/CrN systems with different bilayer periods (8, 19 and 25 nm). Additionally, experimental work has been performed on corresponding TiN and CrN single layers, for comparison purposes. The investigation includes the use of different indenter tip geometries as well as contact loading conditions (i.e. indentation/scratch) such to induce different stress field and damage scenarios within the films. The surface and subsurface damage under the different indentation imprints and scratch tracks have been observed by atomic force microscopy, field emission scanning electron microscopy and focused ion beam. Multilayer TiN/CrN coated systems are found to exhibit higher adhesion strength (under sliding contact load) and cracking resistance (under spherical indentation) than those coated with reference TiN and CrN monolayers. The main reason behind these findings is the effective development of microstructurally-driven deformation and cracking resistant micromechanisms: rotation of columnar grains (and associated distortion of bilayer period) and crack deflection of interlayer thickness length scale, respectively. - Highlights: • Nanomechanical and micromechanical study in TiN/CrN systems • TiN/CrN coated systems exhibit higher adhesion strength and cracking resistance. • Main deformation and cracking micromechanisms: columnar grain rotation and crack deflection.

  19. Characteristics of soil water retention curve at macro-scale

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Scale adaptable hydrological models have attracted more and more attentions in the hydrological modeling research community, and the constitutive relationship at the macro-scale is one of the most important issues, upon which there are not enough research activities yet. Taking the constitutive relationships of soil water movement--soil water retention curve (SWRC) as an example, this study extends the definition of SWRC at the micro-scale to that at the macro-scale, and aided by Monte Carlo method we demonstrate that soil property and the spatial distribution of soil moisture will affect the features of SWRC greatly. Furthermore, we assume that the spatial distribution of soil moisture is the result of self-organization of climate, soil, ground water and soil water movement under the specific boundary conditions, and we also carry out numerical experiments of soil water movement at the vertical direction in order to explore the relationship between SWRC at the macro-scale and the combinations of climate, soil, and groundwater. The results show that SWRCs at the macro-scale and micro-scale presents totally different features, e.g., the essential hysteresis phenomenon which is exaggerated with increasing aridity index and rising groundwater table. Soil property plays an important role in the shape of SWRC which will even lead to a rectangular shape under drier conditions, and power function form of SWRC widely adopted in hydrological model might be revised for most situations at the macro-scale.

  20. Some psychometric characteristics of the Beck's Hopelessness Scale

    Directory of Open Access Journals (Sweden)

    Novović Zdenka

    2005-01-01

    Full Text Available The study tested reliability and construct validity of Serbian translation of Beck's Hopelessness scale on a sample of patients diagnosed as a depressive, anxious and anxious-depressive disorder. Scale was found to have a high degree of internal consistency (Cronbach alpha = 0.91. Principal component analysis, with Scree-test as the criterion of extraction, provided single factor as the best solution. Hopelessness Scale highly correlated with symptoms of depression, low self-concept and depressive automatic thoughts which the authors interpreted as the confirmation of Beck's theory. The hypothesis that hopelessness is construct specific to depression and not to anxiety is, also, confirmed.

  1. Diffusion effects on volume-selective NMR at small length scales; Diffusionseffekte in volumenselektiver NMR auf kleinen Laengenskalen

    Energy Technology Data Exchange (ETDEWEB)

    Gaedke, Achim

    2009-01-21

    In this thesis, the interplay between diffusion and relaxation effects in spatially selective NMR experiments at short length scales is explored. This is especially relevant in the context of both conventional and mechanically detected MRI at (sub)micron resolution in biological specimens. Recent results on selectively excited very thin slices showed an in-slice-magnetization recovery orders of magnitude faster than the longitudinal relaxation time T1. However, those experiments were run on fully relaxed samples while MRI and especially mechanically detected NMR experiments are typically run in a periodic fashion with repetition times far below T1. The main purpose of this work therefore was to extend the study of the interplay between diffusion and longitudinal relaxation to periodic excitations. In some way, this is inverse phenomenon to the DESIRE (Diffusive Enhancement of SIgnal and REsolution) approach, proposed 1992 by Lauterbur. Experiments on periodically excited thin slices were carried out at a dedicated static field gradient cryomagnet with magnetic field gradients up to 180 T/m. In order to obtain plane slices, an appropriate isosurface of the gradient magnet had to be identified. It was found at a field of 3.8 T with a gradient of 73 T/m. In this field, slices down to a thickness of 3.2 {mu}m could be excited. The detection of the NMR signal was done using FIDs instead of echoes as the excitation bandwidth of those thin slices is sufficiently small to observe FIDs which are usually considered to be elusive to detection in such strong static field gradients. A simulation toolbox based on the full Bloch-Torrey-equation was developed to describe the excitation and the formation of NMR signals under those unusual conditions as well as the interplay of diffusion and magnetization recovery. Both the experiments and the simulations indicate that diffusion effects lead to a strongly enhanced magnetization modulation signal also under periodic excitation

  2. Characteristic functions of scale mixtures of multivariate skew-normal distributions

    KAUST Repository

    Kim, Hyoung-Moon

    2011-08-01

    We obtain the characteristic function of scale mixtures of skew-normal distributions both in the univariate and multivariate cases. The derivation uses the simple stochastic relationship between skew-normal distributions and scale mixtures of skew-normal distributions. In particular, we describe the characteristic function of skew-normal, skew-t, and other related distributions. © 2011 Elsevier Inc.

  3. Direct measurement of surface shape for validation of indentation deformation and plasticity length-scale effects: a comparison of methods

    International Nuclear Information System (INIS)

    It is ironic that recent developments in instrumented indentation, such as the drive to obtain tensile properties from indentation data and to understand length-scale effects in plasticity, have seen a return to direct imaging of indentations. Significant uncertainties in contact size arise when using contact mechanics calculations that do not take into account the lateral dilation of elastic recovery (Hou et al 2008 J. Phys. D: Appl. Phys. 41 074006) and important sink-in and pile-up contributions to the contact response (Lim and Chaudhri 1999 Phil. Mag. A 79 2979–3000). High resolution, direct measurement avoids these problems. Accurate wear volume and coating thickness measurements obtained by cap grinding methods also depend on high accuracy and low uncertainty direct measurement methods. The use of metrological atomic force microscopy to measure and certify the shape of indenters is well established (Aldrich-Smith et al 2005 Z. Metallk. 96 1267–71) and is essential for valid mechanical property measurement by instrumented indentation. In this paper, we consider indent measurement and compare three direct measurement techniques: optical microscopy, metrological atomic force microscopy (AFM) and confocal laser scanning microscopy (CLSM). We compare the relative merits and uncertainties of various 2D and 3D analysis methods with a new analysis method of differentiating 3D data obtained from AFM and CLSM. This new method has the lowest uncertainty (2.8% for a 50 µm diameter indent at the 95% confidence level). Better still, it enables objective measurements of indent size that avoid the issues caused by difficult-to-standardize parameters (such as illumination angle, contrast and brightness settings), which strongly affect manual estimates of the edge position of an indentation/crater (Gee et al 2002 NPL Measurement Good Practice Guide No 57)

  4. Imaging of Acoustically Coupled Oscillations Due to Flow Past a Shallow Cavity: Effect of Cavity Length Scale

    Energy Technology Data Exchange (ETDEWEB)

    P Oshkai; M Geveci; D Rockwell; M Pollack

    2004-05-24

    Flow-acoustic interactions due to fully turbulent inflow past a shallow axisymmetric cavity mounted in a pipe, which give rise to flow tones, are investigated using a technique of high-image-density particle image velocimetry in conjunction with unsteady pressure measurements. This imaging leads to patterns of velocity, vorticity, streamline topology, and hydrodynamic contributions to the acoustic power integral. Global instantaneous images, as well as time-averaged images, are evaluated to provide insight into the flow physics during tone generation. Emphasis is on the manner in which the streamwise length scale of the cavity alters the major features of the flow structure. These image-based approaches allow identification of regions of the unsteady shear layer that contribute to the instantaneous hydrodynamic component of the acoustic power, which is necessary to maintain a flow tone. In addition, combined image analysis and pressure measurements allow categorization of the instantaneous flow patterns that are associated with types of time traces and spectra of the fluctuating pressure. In contrast to consideration based solely on pressure spectra, it is demonstrated that locked-on tones may actually exhibit intermittent, non-phase-locked images, apparently due to low damping of the acoustic resonator. Locked-on flow tones (without modulation or intermittency), locked-on flow tones with modulation, and non-locked-on oscillations with short-term, highly coherent fluctuations are defined and represented by selected cases. Depending on which of these regimes occur, the time-averaged Q (quality)-factor and the dimensionless peak pressure are substantially altered.

  5. In situ structural characterization of ageing kinetics in aluminum alloy 2024 across angstrom-to-micrometer length scales

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fan; Levine, Lyle E.; Allen, Andrew J.; Campbell, Carelyn E.; Creuziger, Adam A.; Kazantseva, Nataliya; Ilavsky, Jan

    2016-06-01

    The precipitate structure and precipitation kinetics in an Al-Cu-Mg alloy (AA2024) aged at 190 °C, 208 °C, and 226 °C have been studied using ex situ Transmission Electron Microscopy (TEM) and in situ synchrotron-based, combined ultra-small angle X-ray scattering, small angle X-ray scattering (SAXS), and wide angle X-ray scattering (WAXS) across a length scale from sub-Angstrom to several micrometers. TEM brings information concerning the nature, morphology, and size of the precipitates while SAXS and WAXS provide qualitative and quantitative information concerning the time-dependent size and volume fraction evolution of the precipitates at different stages of the precipitation sequence. Within the experimental time resolution, precipitation at these ageing temperatures involves dissolution of nanometer-sized small clusters and formation of the planar S phase precipitates. Using a three-parameter scattering model constructed on the basis of TEM results, we established the temperature-dependent kinetics for the cluster-dissolution and S-phase formation processes simultaneously. These two processes are shown to have different kinetic rates, with the cluster-dissolution rate approximately double the S-phase formation rate. We identified a dissolution activation energy at (149.5 ± 14.6) kJ mol-1, which translates to (1.55 ± 0.15) eV/atom, as well as an activation energy for the formation of S precipitates at (129.2 ± 5.4) kJ mol-1, i.e. (1.33 ± 0.06) eV/atom. Importantly, the SAXS/WAXS results show the absence of an intermediate Guinier-Preston Bagaryatsky 2 (GPB2)/S" phase in the samples under the experimental ageing conditions. These results are further validated by precipitation simulations that are based on Langer-Schwartz theory and a Kampmann-Wagner numerical method.

  6. Fluid mechanics of dynamic stall. II - Prediction of full scale characteristics

    Science.gov (United States)

    Ericsson, L. E.; Reding, J. P.

    1988-01-01

    Analytical extrapolations are made from experimental subscale dynamics to predict full scale characteristics of dynamic stall. The method proceeds by establishing analytic relationships between dynamic and static aerodynamic characteristics induced by viscous flow effects. The method is then validated by predicting dynamic test results on the basis of corresponding static test data obtained at the same subscale flow conditions, and the effect of Reynolds number on the static aerodynamic characteristics are determined from subscale to full scale flow conditions.

  7. Large-scale evaluation of carnivore road mortality: the effect of landscape and local scale characteristics

    Czech Academy of Sciences Publication Activity Database

    Červinka, J.; Riegert, J.; Grill, S.; Šálek, Martin

    2015-01-01

    Roč. 60, č. 3 (2015), s. 233-243. ISSN 2199-2401 Institutional support: RVO:68081766 Keywords : Carnivores * Landscape characteristics * Linear structures * Local characteristics * Road mortality * Temporal pattern Subject RIV: EH - Ecology, Behaviour

  8. Effect of polydispersity on the structure factor of a melt of binary multiblock copolymers with a two-length-scale macromolecular architecture

    NARCIS (Netherlands)

    Kuchanov, S.; Zharnikov, T.; Brinke, G. ten

    2011-01-01

    A theoretical study on the effect of polydispersity of two-length-scale binary multiblock copolymers on the shape of the structure factor is presented. A bifurcation diagram is constructed showing the partition of the parameter space into domains differing in the way in which the homogeneous melt lo

  9. Mixing Enhancement and Interface Characteristics in a Small-Scale Channel

    Science.gov (United States)

    Noro, Shuta; Kokunai, Kenji; Shigeta, Masaya; Izawa, Seiichiro; Fukunishi, Yu

    The interface characteristics in a millimeter-scale channel are investigated in order to find a technique to speed up fluid mixing. The channel is fabricated on an acrylic-resin plate, where a cavity is attached in the downstream region of a T-shaped conduit. The mixing effect is evaluated using a blue dye and a colorless liquid, which are alternately injected into the channel by two syringe pumps. The important factors for highly efficient mixing under the combination of alternate inflow and cavity are investigated. Two-dimensional and three-dimensional numerical simulations are also performed, and the results are compared those of the experiment. It is confirmed that the fractal dimension and interface length inside a cavity can be used as indicators to predict the mixing level in the downstream region, although they are not perfect. The importance of focusing on both the stretching rate of the interface and the concentration gradient where the stretching of the interface occurs is presented.

  10. Empirical analysis of scaling and fractal characteristics of outpatients

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Li-Jiang, E-mail: zljjiang@gmail.com [College of Management and Economics, Tianjin University, Tianjin 300072 (China); Management Institute, Xinxiang Medical University, Xinxiang 453003, Henan (China); Liu, Zi-Xian, E-mail: liuzixian@tju.edu.cn [College of Management and Economics, Tianjin University, Tianjin 300072 (China); Guo, Jin-Li, E-mail: phd5816@163.com [Business School, University of Shanghai for Science and Technology, Shanghai 200093 (China)

    2014-01-31

    The paper uses power-law frequency distribution, power spectrum analysis, detrended fluctuation analysis, and surrogate data testing to evaluate outpatient registration data of two hospitals in China and to investigate the human dynamics of systems that use the “first come, first served” protocols. The research results reveal that outpatient behavior follow scaling laws. The results also suggest that the time series of inter-arrival time exhibit 1/f noise and have positive long-range correlation. Our research may contribute to operational optimization and resource allocation in hospital based on FCFS admission protocols.

  11. Empirical analysis of scaling and fractal characteristics of outpatients

    International Nuclear Information System (INIS)

    The paper uses power-law frequency distribution, power spectrum analysis, detrended fluctuation analysis, and surrogate data testing to evaluate outpatient registration data of two hospitals in China and to investigate the human dynamics of systems that use the “first come, first served” protocols. The research results reveal that outpatient behavior follow scaling laws. The results also suggest that the time series of inter-arrival time exhibit 1/f noise and have positive long-range correlation. Our research may contribute to operational optimization and resource allocation in hospital based on FCFS admission protocols.

  12. Characteristic angular scales in cosmic microwave background radiation

    International Nuclear Information System (INIS)

    We investigate the stochasticity in temperature fluctuations in the cosmic microwave background (CMB) radiation data from the Wilkinson Microwave Anisotropy Probe. We show that the angular fluctuation of the temperature is a Markov process with a Markov angular scale, Markov 1.01-0.07+0.09. We characterize the complexity of the CMB fluctuations by means of a Fokker-Planck or Langevin equation and measure the associated Kramers-Moyal coefficients for the fluctuating temperature field T(n-circumflex) and its increment, ΔT = T(n-circumflex1) - T(n-circumflex2). Through this method we show that temperature fluctuations in the CMB have fat tails compared to a Gaussian distribution. (author)

  13. Development of Lab-to-Fab Production Equipment Across Several Length Scales for Printed Energy Technologies, Including Solar Cells

    DEFF Research Database (Denmark)

    Hösel, Markus; Dam, Henrik Friis; Krebs, Frederik C

    2015-01-01

    We describe and review how the scaling of printed energy technologies not only requires scaling of the input materials but also the machinery used in the processes. The general consensus that ultrafast processing of technologies with large energy capacity can only be realized using roll-to-roll m...

  14. Comparative Study of Laboratory-Scale and Prototypic Production-Scale Fuel Fabrication Processes and Product Characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Douglas W. Marshall

    2014-10-01

    An objective of the High Temperature Gas Reactor fuel development and qualification program for the United States Department of Energy has been to qualify fuel fabricated in prototypic production-scale equipment. The quality and characteristics of the tristructural isotropic coatings on fuel kernels are influenced by the equipment scale and processing parameters. Some characteristics affecting product quality were suppressed while others have become more significant in the larger equipment. Changes to the composition and method of producing resinated graphite matrix material has eliminated the use of hazardous, flammable liquids and enabled it to be procured as a vendor-supplied feed stock. A new method of overcoating TRISO particles with the resinated graphite matrix eliminates the use of hazardous, flammable liquids, produces highly spherical particles with a narrow size distribution, and attains product yields in excess of 99%. Compact fabrication processes have been scaled-up and automated with relatively minor changes to compact quality to manual laboratory-scale processes. The impact on statistical variability of the processes and the products as equipment was scaled are discussed. The prototypic production-scale processes produce test fuels that meet fuel quality specifications.

  15. Metric characteristics of Anxiety Scale for Children and Adolescents: A preliminary study

    OpenAIRE

    Ana Krevh

    2007-01-01

    The paper is exploring measurements of anxiety in youth and adolescence. It introduces a new scale for measuring anxiety in youth and adolescence (LAOM) and selected metric characteristics are being analysed. The scale was designed to measure general level of anxiety in school surroundings. The concept of anxiety and the evolvement of measures are highlighted and the theoretical base for construction of the new scale is presented. The psychometric analyses were based on a sample of 300 elemen...

  16. Technical measures without enforcement tools: is there any sense? A methodological approach for the estimation of passive net length in small scale fisheries

    Directory of Open Access Journals (Sweden)

    A. LUCCHETTI

    2015-01-01

    Full Text Available Passive nets are currently among the most important fishing gears largely used along the Mediterranean coasts by the small scale fisheries sector. The fishing effort exerted by this sector is strongly correlated with net dimensions. Therefore, the use of passive nets is worldwide managed by defining net length and net drop. The EC Reg. 1967/2006 reports that the length of bottom-set and drifting nets may be also defined considering their weight or volume; however, no practical suggestions for fisheries inspectors are yet available. Consequently,  even if such technical measures are reasonable from a theoretical viewpoint, they are hardly suitable as a management tool, due to the difficulties in harbour control. The overall objective of this paper is to provide a quick methodological approach for the gross estimation of passive net length (by net type on the basis of net volume. The final goal is to support fisheries managers with suitable advice for enforcement and control purposes. The results obtained are important for the management of the fishing effort exerted by small scale fisheries. The methodology developed in this study should be considered as a first attempt to tackle the tangled problem of net length estimation that can be easily applied in other fisheries and areas in order to improve the precision of the models developed herein.

  17. Enhanced strength and temperature dependence of mechanical properties of Li at small length scales and its implications for Li metal anodes

    CERN Document Server

    and, Chen Xu; Aryanfar, Asghar; Viswanathan, Venkatasubramanian; Greer, Julia R

    2016-01-01

    Most next-generation Li-ion battery chemistries require a functioning lithium metal (Li) anode. However, its application in secondary batteries has been inhibited because of uncontrollable dendrite growth during cycling. Mechanical suppression of dendrite growth through solid polymer electrolytes (SPE) or through robust separators has shown the most potential for alleviating this problem. Studies of the mechanical behavior of Li at any length scale and temperature are virtually non-existent because of its extreme reactivity, which renders sample preparation, transfer, microstructure characterization and mechanical testing prohibitively challenging. We conduct nano-mechanical experiments in an in-situ Scanning Electron Microscope and show that micron-sized Li attains extremely high strengths of 105 MPa at room temperature and of 35MPa at 90$^\\circ$C. We demonstrate that single crystalline Li exhibits a power-law size-effect at the micron- and sub-micron length scales, with the strengthening exponent of -0.68 a...

  18. Wind tunnel investigation of aerodynamic characteristics of a scale model of a D5 bulldozer and an M109 self-propelled 155 mm Howitzer

    Science.gov (United States)

    Laub, G. H.; Kodani, H. M.

    1974-01-01

    Wind tunnel tests were conducted on a scale model of a D5 bulldozer and an M109 self-propelled 155 MM howitzer to determine the aerodynamic characteristics of these typical externally-suspended heavy lift helicopter cargo configurations. Tests were made over a large range of pitch and yaw attitudes at a nominal Reynolds number per unit length of 1.5 x 10 to the 6th power.

  19. Morphological quantification of hierarchical geomaterials by X-ray nano-CT bridges the gap from nano to micro length scales

    OpenAIRE

    Brisard, Sébastien; CHAE, Rosie S; Bihannic, Isabelle; Michot, Laurent; GUTTMANN, Peter; Schneider, Gerd; MONTEIRO, Paulo JM; LEVITZ, Pierre; Thieme, Jürgen

    2012-01-01

    Morphological quantification of the complex structure of hierarchical geomaterials is of great relevance for Earth science and environmental engineering, among others. To date, methods that quantify the 3D morphology on length scales ranging from a few tens of nanometers to several hundred nanometers have had limited success. We demonstrate, for the first time, that it is possible to go beyond visualization and to extract quantitative morphological information from X-ray images in the aforeme...

  20. Development of Lab-to-Fab Production Equipment Across Several Length Scales for Printed Energy Technologies, Including Solar Cells

    DEFF Research Database (Denmark)

    Hösel, Markus; Dam, Henrik Friis; Krebs, Frederik C

    2015-01-01

    We describe and review how the scaling of printed energy technologies not only requires scaling of the input materials but also the machinery used in the processes. The general consensus that ultrafast processing of technologies with large energy capacity can only be realized using roll-to-roll m...... lower end of the industrial scale. The machinery bridges the gap through firstly achieving improved ink efficiency without surface contact, followed by better ink efficiency at higher speeds, and finally large-area processing at high speed with very high ink efficiency....

  1. A direct dynamical measurement of the Milky Way's disk surface density profile, disk scale length, and dark matter profile at 4 kpc < R < 9 kpc

    CERN Document Server

    Bovy, Jo

    2013-01-01

    We present and apply rigorous dynamical modeling with which we infer unprecedented constraints on the stellar and dark matter mass distribution within our Milky Way (MW), based on large sets of phase-space data on individual stars. Specifically, we model the dynamics of 16,269 G-type dwarfs from SEGUE, which sample 5 < R/kpc < 12 and 0.3 < |Z|/kpc < 3. We independently fit a parameterized MW potential and a three-integral, action-based distribution function (DF) to the phase-space data of 43 separate abundance-selected sub-populations (MAPs), accounting for the complex selection effects affecting the data. We robustly measure the total surface density within 1.1 kpc of the mid-plane to about 5% over the range 4.5< R/kpc < 9. Using metal-poor MAPs with small radial scale lengths as dynamical tracers probes 4.5 < R/kpc < 7, while MAPs with longer radial scale lengths sample 7 < R/kpc < 9. We measure the mass-weighted Galactic disk scale length to be R_d = 2.15+/-0.14 kpc, in agreem...

  2. Upscaling drought information from the catchment scale to the global scale: how seasonality in climate influences drought characteristics

    Science.gov (United States)

    Van Loon, Anne; Tijdeman, Erik; Wanders, Niko; Van Lanen, Henny; Teuling, Adriaan; Uijlenhoet, Remko

    2013-04-01

    The upscaling of the understanding of hydrological processes from the catchment scale to the global scale is not straightforward, especially not for hydrological extremes as floods and droughts. For large-scale water resources management, information on the development and persistence of soil moisture and hydrological droughts is crucial. The characteristics of these droughts (i.e. duration and severity) vary around the world and are dependent on climate and catchment properties. In this study, we investigated climate controls on drought propagation (i.e. the translation of meteorological conditions to a soil moisture drought and/or hydrological drought) by isolating forcing effects from effects of catchment properties. We used a conceptual hydrological model, forced by the WATCH forcing data, that was run for 1271 grid cells distributed over the global climate zones. The precipitation that was used as input, and soil moisture storage and subsurface discharge that were outcomes of the model, were then analysed with a well-known drought identification method (variable threshold level method). Drought characteristics duration and standardised deficit (deficit below the smoothed monthly-varying threshold, divided by the mean of the variable for that grid cell) were determined for each drought event. These drought characteristics were clustered per subclimate type and combined into bivariate probability density fields. The shape and orientation of these density fields provide information on the propagation of drought in different climate zones. Drought propagation features that are apparent on the catchment scale, such as pooling (meteorological droughts are merged into a prolonged hydrological drought) and attenuation (the damping effect of stores on the drought signal), were reproduced in all climate zones. But also seasonal drought types that can have severe impacts on the catchment scale (e.g. rain-to-snow-season drought) leave a pronounced signal in the density

  3. Length-scale dependent microalloying effects on precipitation behaviors and mechanical properties of Al–Cu alloys with minor Sc addition

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, L.; Li, J.K. [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Liu, G., E-mail: lgsammer@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Wang, R.H. [School of Materials Science and Engineering, Xi' an University of Technology, Xi' an 710048 (China); Chen, B.A.; Zhang, J.Y. [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Sun, J., E-mail: junsun@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Yang, M.X.; Yang, G. [Central Iron and Steel Research Institute, Beijing 100081 (China); Yang, J.; Cao, X.Z. [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2015-06-18

    Heat-treatable Al alloys containing Al–2.5 wt% Cu (Al–Cu) and Al–2.5 wt% Cu–0.3 wt% Sc (Al–Cu–Sc) with different grain length scales, i.e., average grain size >10 μm ( defined coarse grained, CG), 1–2 μm (fine grained, FG), and <1 μm (ultrafine grained, UFG), were prepared by equal-channel angular pressing (ECAP). The length scale and Sc microalloying effects and their interplay on the precipitation behavior and mechanical properties of the Al–Cu alloys were systematically investigated. In the Al–Cu alloys, intergranular θ-Al{sub 2}Cu precipitation gradually dominated by sacrificing the intragranular θ′-Al{sub 2}Cu precipitation with reducing the length scale. Especially in the UFG regime, only intergranular θ-Al{sub 2}Cu particles were precipitated and intragranular θ′-Al{sub 2}Cu precipitation was completely disappeared. This led to a remarkable reduction in yield strength and ductility due to insufficient dislocation storage capacity. The minor Sc addition resulted in a microalloying effect in the Al–Cu alloy, which, however, is strongly dependent on the length scale. The smaller is the grain size, the more active is the microalloying effect that promotes the intragranular precipitation while reduces the intergranular precipitation. Correspondingly, compared with their Sc-free counterparts, the yield strength of post-aged CG, FG, and UFG Al–Cu alloys with Sc addition increased by ~36 MPa, ~56 MPa, and ~150 MPa, simultaneously in tensile elongation by ~20%, ~30%, and 280%, respectively. The grain size-induced evolutions in vacancy concentration/distribution and number density of vacancy-solute/solute–solute clusters and their influences on precipitation nucleation and kinetics have been comprehensively considered to rationalize the length scale-dependent Sc microalloying mechanisms using positron annihilation lifetime spectrum and three dimension atom probe. The increase in ductility was analyzed in the light of Sc microalloying

  4. Length-Scale-Dependent Phase Transformation of LiFePO4 : An In situ and Operando Study Using Micro-Raman Spectroscopy and XRD.

    Science.gov (United States)

    Siddique, N A; Salehi, Amir; Wei, Zi; Liu, Dong; Sajjad, Syed D; Liu, Fuqiang

    2015-08-01

    The charge and discharge of lithium ion batteries are often accompanied by electrochemically driven phase-transformation processes. In this work, two in situ and operando methods, that is, micro-Raman spectroscopy and X-ray diffraction (XRD), have been combined to study the phase-transformation process in LiFePO4 at two distinct length scales, namely, particle-level scale (∼1 μm) and macroscopic scale (∼several cm). In situ Raman studies revealed a discrete mode of phase transformation at the particle level. Besides, the preferred electrochemical transport network, particularly the carbon content, was found to govern the sequence of phase transformation among particles. In contrast, at the macroscopic level, studies conducted at four different discharge rates showed a continuous but delayed phase transformation. These findings uncovered the intricate phase transformation in LiFePO4 and potentially offer valuable insights into optimizing the length-scale-dependent properties of battery materials. PMID:26073651

  5. Criterion Noise in Ratings-Based Recognition: Evidence from the Effects of Response Scale Length on Recognition Accuracy

    Science.gov (United States)

    Benjamin, Aaron S.; Tullis, Jonathan G.; Lee, Ji Hae

    2013-01-01

    Rating scales are a standard measurement tool in psychological research. However, research has suggested that the cognitive burden involved in maintaining the criteria used to parcel subjective evidence into ratings introduces "decision noise" and affects estimates of performance in the underlying task. There has been debate over whether…

  6. Preliminary simulation of hyporheic hydrology suggests systematic changes in hyporheic flow path length and residence time in response to reach-scale channel restoration in Meacham Creek, OR

    Science.gov (United States)

    Amerson, B. E.; Poole, G.

    2011-12-01

    Hyporheic hydrologic response to stream restoration has typically focused on hydrodynamics associated with individual features or habitat units rather than whole reaches. Here we present preliminary results from MODFLOW simulations that compare modeled hyporheic hydrology prior to and after major channel reconfiguration associated with a recently completed reach-scale channel restoration on Meacham Creek in northeastern Oregon. Our model was parameterized using LiDAR floodplain surface elevation data and empirically-derived estimates of aquifer properties. Results show that groundwater flow path length and cumulative residence time distributions are apt to be altered by channel reconfiguration. For example, our model shows that the relatively high-gradient and straight baseline channel is dominated by either short or long flow path lengths, with relatively few medium length flow paths. In contrast, the proposed restoration channel is more sinuous and has a lower gradient. Our modeling suggests that the restoration channel will have a broader distribution of flow path lengths and residence times. We used model results to select well locations for intensive monitoring of groundwater surface elevation and temperature. Monitoring will continue through 2012 and is designed to evaluate model predictions as well as to document the effects of the channel restoration on surface water-groundwater interactions and concomitant effects on water temperature.

  7. Extracting Length and Time Scales of Downstream Suspended Transport from Sediment Budget Data: ~100 to 1000-yr Travel Times from the Appalachians to the Chesapeake Bay, U.S.A

    Science.gov (United States)

    Pizzuto, J. E.; Schenk, E.; Hupp, C. R.; Gellis, A.; Noe, G. B.; Williamson, E.; Karwan, D. L.; O'Neal, M. A.; Marquard, J.; Aalto, R. E.; Newbold, J. D.

    2013-12-01

    Watershed Best Management Practices (BMPs) are often designed to reduce loadings of sediments and particle-borne contaminants, but the temporal lag between BMP implementation and improvement in receiving water quality is difficult to assess because particles spend long periods in storage between transport events. Here we present a theory that describes the downstream movement of suspended sediment particles accounting for the time particles spend in storage based on sediment budget data (by grain-size fraction) and information on particle transit times through storage reservoirs. The theory is used to define a suspended-sediment transport-length scale that describes how far particles are carried during transport events, and to estimate a downstream particle velocity that includes time spent in storage. At five upland watersheds of the mid-Atlantic region of the U.S.A., transport-length scales for silt-clay range from 3.5-76.1 km, while those for sand range from 0.9-139.6 km. Stratigraphic data and radiometric dating for a typical eroding bank section suggest an averaged sediment transit time through floodplain storage of 488 years. Mean sediment velocities for silt-clay range from 0.0072-0.16 km/yr, while those for sand range from 0.0008-0.25 km/yr, 4 to 6 orders of magnitude slower than the velocity of water in the channel. These results suggest lag times of 100-1000 years between BMP implementation and effectiveness in receiving waters such as the Chesapeake Bay (where BMPs are located upstream of the characteristic transport length scale). Many particles likely travel much faster than these average values, so further research is needed to define the range and distribution of transport rates within and across particle sizes.

  8. Effects of Physical Processes and Sampling Resolution on Fault Displacement Versus Length Scaling: The Case of the Cantarell Complex Oilfield, Gulf of Mexico

    Science.gov (United States)

    Xu, Shunshan; Nieto-Samaniego, Angel F.; Murillo-Muñetón, Gustavo; Alaniz-Álvarez, Susana A.; Grajales-Nishimura, José M.; Velasquillo-Martinez, Luis G.

    2016-04-01

    In this paper, we first review some factors that may alter the fault D max /L ratio and scaling relationship. The three main physical processes are documented as follows: (1) The D max /L ratio increases in an individual segmented fault, whereas it decreases in a fault array consisting of two or more fault segments. This effect occurs at any scale during fault growth and in any type of rock. (2) Vertical restriction decreases the D max /L ratio along the fault strike due to mechanical layers. (3) The D max /L ratio increases or decreases due to fault reactivation depending on the type of reactivation. Thus, using data from the normal faults of the Cantarell oilfield in the southern Gulf of Mexico, we document that the displacement ( D max ) and length ( L) show a weak correlation of linear or power-law scaling, with exponents that are much less than 1 ( n ≈ 0.5). This scaling relation is due to the combination of the physical processes mentioned above, as well as sampling effects, such as technique resolution. These results indicate that sublinear scaling ( n ≈ 0.5) can occur as a result of more than one physical process during faulting in a studied area. In addition to the physical processes associated with brittle deformation in the studied area, the sampling resolution dramatically affects the exponents of the D max - L scaling.

  9. Scaling between superconducting critical temperature and structural coherence length in YBa{sub 2}Cu{sub 3}O{sub 6.9} films

    Energy Technology Data Exchange (ETDEWEB)

    Gauzzi, A. [Ecole Polytechnique Federale, Lausanne (Switzerland). Dept. de Physique; Consiglio Nazionale delle Ricerche, Parma (Italy). Lab. MASPEC; Joensson-Aakerman, B.J.; Clerc-Dubois, A.; Pavuna, D. [Ecole Polytechnique Federale, Lausanne (Switzerland). Dept. de Physique

    2000-09-15

    Measurements of critical temperature T{sub c} in superconducting YBa{sub 2}Cu{sub 3}O{sub 6.9} films with reduced long-range structural order show the validity of the empirical scaling relation {delta}T{sub c}{proportional_to}r{sub c}{sup -2} between disorder-induced reduction of T{sub c} and structural coherence length r{sub c} in the ab-plane. This result is quantitatively explained by the disorder-induced confinement of the charge carriers within each ordered domain of size r{sub c}. Our analysis of the data based on this picture enables us to precisely determine the Ginzburg-Landau superconducting coherence length in the ab-plane, {xi}{sub ab} = 1.41 {+-} 0.04 nm. (orig.)

  10. Perceived characteristics of the environment associated with active travel: development and testing of a new scale

    OpenAIRE

    Mutrie Nanette; Mitchell Richard; Ogilvie David; Petticrew Mark; Platt Stephen

    2008-01-01

    Abstract Background Environmental characteristics may be associated with patterns of physical activity. However, the development of instruments to measure perceived characteristics of the local environment is still at a comparatively early stage, and published instruments are not necessarily suitable for application in all settings. We therefore developed and established the test-retest reliability of a new scale for use in a study of the correlates of active travel and overall physical activ...

  11. Searching and fixating: scale-invariance vs. characteristic timescales in attentional processes

    CERN Document Server

    Shinde, D P; Mishra, R K

    2011-01-01

    In an experiment involving semantic search, the visual movements of sample populations subjected to visual and aural input were tracked in a taskless paradigm. The probability distributions of saccades and fixations were obtained and analyzed. Scale-invariance was observed in the saccadic distributions, while the fixation distributions revealed the presence of a characteristic (attentional) time scale for literate subjects. A detailed analysis of our results suggests that saccadic eye motions are an example of Levy, rather than Brownian, dynamics.

  12. Morphological quantification of hierarchical geomaterials by X-ray nano-CT bridges the gap from nano to micro length scales

    KAUST Repository

    Brisard, S.

    2012-01-30

    Morphological quantification of the complex structure of hierarchical geomaterials is of great relevance for Earth science and environmental engineering, among others. To date, methods that quantify the 3D morphology on length scales ranging from a few tens of nanometers to several hun-dred nanometers have had limited success. We demonstrate, for the first time, that it is possible to go beyond visualization and to extract quantitative morphological information from X-ray images in the aforementioned length scales. As examples, two different hierarchical geomaterials exhibiting complex porous structures ranging from nanometer to macroscopic scale are studied: a flocculated clay water suspension and two hydrated cement pastes. We show that from a single projection image it is possible to perform a direct computation of the ultra-small angle-scattering spectra. The predictions matched very well the experimental data obtained by the best ultra-small angle-scattering experimental setups as observed for the cement paste. In this context, we demonstrate that the structure of flocculated clay suspension exhibit two well-distinct regimes of aggregation, a dense mass fractal aggregation at short distance and a more open structure at large distance, which can be generated by a 3D reaction limited cluster-cluster aggregation process. For the first time, a high-resolution 3D image of fibrillar cement paste cluster was obtained from limited angle nanotomography.

  13. Density and temperature characterization of long-scale length, near-critical density controlled plasma produced from ultra-low density plastic foam

    Science.gov (United States)

    Chen, S. N.; Iwawaki, T.; Morita, K.; Antici, P.; Baton, S. D.; Filippi, F.; Habara, H.; Nakatsutsumi, M.; Nicolaï, P.; Nazarov, W.; Rousseaux, C.; Starodubstev, M.; Tanaka, K. A.; Fuchs, J.

    2016-02-01

    The ability to produce long-scale length (i.e. millimeter scale-length), homogeneous plasmas is of interest in studying a wide range of fundamental plasma processes. We present here a validated experimental platform to create and diagnose uniform plasmas with a density close or above the critical density. The target consists of a polyimide tube filled with an ultra low-density plastic foam where it was heated by x-rays, produced by a long pulse laser irradiating a copper foil placed at one end of the tube. The density and temperature of the ionized foam was retrieved by using x-ray radiography and proton radiography was used to verify the uniformity of the plasma. Plasma temperatures of 5-10 eV and densities around 1021 cm-3 are measured. This well-characterized platform of uniform density and temperature plasma is of interest for experiments using large-scale laser platforms conducting High Energy Density Physics investigations.

  14. Nano-regime Length Scales Extracted from the First Sharp Diffraction Peak in Non-crystalline SiO2 and Related Materials: Device Applications

    Directory of Open Access Journals (Sweden)

    Phillips James

    2010-01-01

    Full Text Available Abstract This paper distinguishes between two different scales of medium range order, MRO, in non-crystalline SiO2: (1 the first is ~0.4 to 0.5 nm and is obtained from the position of the first sharp diffraction peak, FSDP, in the X-ray diffraction structure factor, S(Q, and (2 the second is ~1 nm and is calculated from the FSDP full-width-at-half-maximum FWHM. Many-electron calculations yield Si–O third- and O–O fourth-nearest-neighbor bonding distances in the same 0.4–0.5 nm MRO regime. These derive from the availability of empty Si dπ orbitals for back-donation from occupied O pπ orbitals yielding narrow symmetry determined distributions of third neighbor Si–O, and fourth neighbor O–O distances. These are segments of six member rings contributing to connected six-member rings with ~1 nm length scale within the MRO regime. The unique properties of non-crystalline SiO2 are explained by the encapsulation of six-member ring clusters by five- and seven-member rings on average in a compliant hard-soft nano-scaled inhomogeneous network. This network structure minimizes macroscopic strain, reducing intrinsic bonding defects as well as defect precursors. This inhomogeneous CRN is enabling for applications including thermally grown ~1.5 nm SiO2 layers for Si field effect transistor devices to optical components with centimeter dimensions. There are qualitatively similar length scales in nano-crystalline HfO2 and phase separated Hf silicates based on the primitive unit cell, rather than a ring structure. Hf oxide dielectrics have recently been used as replacement dielectrics for a new generation of Si and Si/Ge devices heralding a transition into nano-scale circuits and systems on a Si chip.

  15. Scaling of Teak (Tectona grandis) Logs by the Xylometer Technique: Accuracy of Volume Equations and Influence of the Log Length

    OpenAIRE

    Kouami Kokou; Noël H. Fonton; Arcadius Y. J. Akossou; Eloi Y. Attakpa; Soufianou Arzouma

    2013-01-01

    The accuracy of ten methods of scaling (Smalian, Huber, Newton, Neloïd, paraboloid, cone, paracone, cylinder, truncated cone and truncated Neloïd) was evaluated on logs of 0.5, 1, 2 and 3 m cut to different heights of 27 teak trees. For this purpose, the volumes estimated by the ten formulas were compared with real volumes obtained by the technique of xylometer. The results obtained showed that the method of Huber was more efficient to calculate the volume of logs throughout the stem when the...

  16. Probing grain boundary sink strength at the nanoscale: Energetics and length scales of vacancy and interstitial absorption by grain boundaries in α-Fe

    Energy Technology Data Exchange (ETDEWEB)

    Tschopp, Mark A.; Solanki, K. N.; Gao, Fei; Sun, Xin; Khaleel, Mohammad A.; Horstemeyer, Mark

    2012-02-10

    The energetics and length scales associated with the interaction between point defects (vacancies and self-interstitial atoms) and grain boundaries in bcc Fe was explored. Molecular statics simulations were used to generate a grain boundary structure database that contained {approx}170 grain boundaries with varying tilt and twist character. Then, vacancy and self-interstitial atom formation energies were calculated at all potential grain boundary sites within 15 {angstrom} of the boundary. The present results provide detailed information about the interaction energies of vacancies and self-interstitial atoms with symmetric tilt grain boundaries in iron and the length scales involved with absorption of these point defects by grain boundaries. Both low- and high-angle grain boundaries were effective sinks for point defects, with a few low-{Sigma} grain boundaries (e.g., the {Sigma}3{l_brace}112{r_brace} twin boundary) that have properties different from the rest. The formation energies depend on both the local atomic structure and the distance from the boundary center. Additionally, the effect of grain boundary energy, disorientation angle, and {Sigma} designation on the boundary sink strength was explored; the strongest correlation occurred between the grain boundary energy and the mean point defect formation energies. Based on point defect binding energies, interstitials have {approx}80% more grain boundary sites per area and {approx}300% greater site strength than vacancies. Last, the absorption length scale of point defects by grain boundaries is over a full lattice unit larger for interstitials than for vacancies (mean of 6-7 {angstrom} versus 10-11 {angstrom} for vacancies and interstitials, respectively).

  17. Probing grain boundary sink strength at the nanoscale: Energetics and length scales of vacancy and interstitial absorption by grain boundaries in α-Fe

    Science.gov (United States)

    Tschopp, M. A.; Solanki, K. N.; Gao, F.; Sun, X.; Khaleel, M. A.; Horstemeyer, M. F.

    2012-02-01

    The energetics and length scales associated with the interaction between point defects (vacancies and self-interstitial atoms) and grain boundaries in bcc Fe was explored. Molecular statics simulations were used to generate a grain boundary structure database that contained ≈170 grain boundaries with varying tilt and twist character. Then, vacancy and self-interstitial atom formation energies were calculated at all potential grain boundary sites within 15 Å of the boundary. The present results provide detailed information about the interaction energies of vacancies and self-interstitial atoms with symmetric tilt grain boundaries in iron and the length scales involved with absorption of these point defects by grain boundaries. Both low- and high-angle grain boundaries were effective sinks for point defects, with a few low-Σ grain boundaries (e.g., the Σ3{112} twin boundary) that have properties different from the rest. The formation energies depend on both the local atomic structure and the distance from the boundary center. Additionally, the effect of grain boundary energy, disorientation angle, and Σ designation on the boundary sink strength was explored; the strongest correlation occurred between the grain boundary energy and the mean point defect formation energies. Based on point defect binding energies, interstitials have ≈80% more grain boundary sites per area and ≈300% greater site strength than vacancies. Last, the absorption length scale of point defects by grain boundaries is over a full lattice unit larger for interstitials than for vacancies (mean of 6-7 Å versus 10-11 Å for vacancies and interstitials, respectively).

  18. Multi-length-scale Material Model for SiC/SiC Ceramic-Matrix Composites (CMCs): Inclusion of In-Service Environmental Effects

    Science.gov (United States)

    Grujicic, M.; Galgalikar, R.; Snipes, J. S.; Ramaswami, S.

    2016-01-01

    In our recent work, a multi-length-scale room-temperature material model for SiC/SiC ceramic-matrix composites (CMCs) was derived and parameterized. The model was subsequently linked with a finite-element solver so that it could be used in a general room-temperature, structural/damage analysis of gas-turbine engine CMC components. Due to its multi-length-scale character, the material model enabled inclusion of the effects of fiber/tow (e.g., the volume fraction, size, and properties of the fibers; fiber-coating material/thickness; decohesion properties of the coating/matrix interfaces; etc.) and ply/lamina (e.g., the 0°/90° cross-ply versus plain-weave architectures, the extent of tow crimping in the case of the plain-weave plies, cohesive properties of the inter-ply boundaries, etc.) length-scale microstructural/architectural parameters on the mechanical response of the CMCs. One of the major limitations of the model is that it applies to the CMCs in their as-fabricated conditions (i.e., the effect of prolonged in-service environmental exposure and the associated material aging-degradation is not accounted for). In the present work, the model is upgraded to include such in-service environmental-exposure effects. To demonstrate the utility of the upgraded material model, it is used within a finite-element structural/failure analysis involving impact of a toboggan-shaped turbine shroud segment by a foreign object. The results obtained clearly revealed the effects that different aspects of the in-service environmental exposure have on the material degradation and the extent of damage suffered by the impacted CMC toboggan-shaped shroud segment.

  19. Role of Shear and the Inversion Strength During Sunset Turbulence Over Land: Characteristic Length Scales, pre print

    NARCIS (Netherlands)

    Pino, D.; Jonker, H.J.J.; Vilà-Guerau de Arellano, J.; Dosio, A.

    2006-01-01

    The role of shear and inversion strength on the decay of convective turbulence during sunset over land is systematically studied by means of large-eddy simulations. Different decay rates have been found for the vertical and horizontal velocity fluctuations, resulting in an increase of the anisotropy

  20. Effects of soil spatial variability at the hillslope and catchment scales on characteristics of rainfall-induced landslides

    Science.gov (United States)

    Fan, Linfeng; Lehmann, Peter; Or, Dani

    2016-03-01

    Spatial variations in soil properties affect key hydrological processes, yet their role in soil mechanical response to hydro-mechanical loading is rarely considered. This study aims to fill this gap by systematically quantifying effects of spatial variations in soil type and initial water content on rapid rainfall-induced shallow landslide predictions at the hillslope- and catchment-scales. We employed a physically-based landslide triggering model that considers mechanical interactions among soil columns governed by strength thresholds. At the hillslope scale, we found that the emergence of weak regions induced by spatial variations of soil type and initial water content resulted in early triggering of landslides with smaller volumes of released mass relative to a homogeneous slope. At the catchment scale, initial water content was linked to a topographic wetness index, whereas soil type varied deterministically with soil depth considering spatially correlated stochastic components. Results indicate that a strong spatial organization of initial water content delays landslide triggering, whereas spatially linked soil type with soil depth promoted landslide initiation. Increasing the standard deviation and correlation length of the stochastic component of soil type increases landslide volume and hastens onset of landslides. The study illustrates that for similar external boundary conditions and mean soil properties, landslide characteristics vary significantly with soil variability, hence it must be considered for improved landslide model predictions.

  1. Bias Adaptation for Vocal Tract Length Normalization

    OpenAIRE

    Saheer, Lakshmi; Yamagishi, Junichi; Garner, Philip N.; Dines, John

    2013-01-01

    Vocal tract length normalisation (VTLN) is a well known rapid adaptation technique. VTLN as a linear transformation in the cepstral domain results in the scaling and translation factors. The warping factor represents the spectral scaling parameter. While, the translation factor represented by bias term captures more speaker characteristics especially in a rapid adaptation framework without having the risk of over-fitting. This paper presents a complete and comprehensible derivation of the bia...

  2. Liquid drop heat and mass transfer characteristic analysis by using scaling analysis method in containment

    International Nuclear Information System (INIS)

    In the containment analysis of nuclear power plant, containment scaling analysis could be used to confirm the important phenomena of containment cooling system and demonstrate the sufficiency of test data. Based on the design basis accident (DBA) of passive nuclear power plant, the scaling analysis method was used to quantify the effect of heat and mass transfer characteristic of liquid drop to mass, energy and RPC. The effect of containment cooling system phenomena to containment pressure response can be confirmed by this scaling analysis. (authors)

  3. Controlling the length scale and distribution of the ductile phase in metallic glass composites through friction stir processing

    International Nuclear Information System (INIS)

    We demonstrate the refinement and uniform distribution of the crystalline dendritic phase by friction stir processing (FSP) of titanium based in situ ductile-phase reinforced metallic glass composite. The average size of the dendrites was reduced by almost a factor of five (from 24 μm to 5 μm) for the highest tool rotational speed of 900 rpm. The large inter-connected dendrites become more fragmented with increased circularity after processing. The changes in thermal characteristics were measured by differential scanning calorimetry. The reduction in crystallization enthalpy after processing suggests partial devitrification due to the high strain plastic deformation. FSP resulted in increased hardness and modulus for both the amorphous matrix and the crystalline phase. This is explained by interaction of shear bands in amorphous matrix with the strain-hardened dendritic phase. Our approach offers a new strategy for microstructural design in metallic glass composites. (paper)

  4. Length Scale Dependence of Periodic Textures for Photoabsorption Enhancement in Ultra-thin Silicon Foils and Thick Wafers

    CERN Document Server

    Kumar, K; Liu, G; Nogami, J; Kherani, N P

    2016-01-01

    In this paper, we simulate a front surface inverted pyramidal grating texture on 2 to 400 micron thick silicon and optimize it to derive maximum photocurrent density from the cell. We identify a one size fits all front grating period of 1000 nm that leads to maximum photo-absorption of normally incident AM1.5g solar spectrum in silicon (configured with a back surface reflector) irrespective of the thickness of the crystalline silicon absorbing layer. With the identification of such universally optimized periodicity for the case of an inverted pyramidal grating texture, a common fabrication process can be designed to manufacture high-efficiency devices on crystalline silicon regardless of wafer thickness. In order to validate the results of the simulation, we fabricated high resolution inverted pyramidal textures on a 400 micron thick silicon wafer with electron beam lithography to compare the reflectance from submicron and wavelength scale periodic textures. The experimental reflectance measurements on textur...

  5. Parent Behavior Importance Questionnaire-Revised: Scale Development and Psychometric Characteristics

    Science.gov (United States)

    Mowder, Barbara A.; Shamah, Renee

    2011-01-01

    This paper reports the scale development and psychometric characteristics of the Parent Behavior Importance Questionnaire-Revised (PBIQ-R). To develop this measure, 502 subject matter experts (SMEs) evaluated 91 parenting behaviors in terms of parenting behavior specificity (e.g., bonding, discipline), importance level, and appropriateness for…

  6. Effects on Scale Linking of Different Definitions of Criterion Functions for the IRT Characteristic Curve Methods

    Science.gov (United States)

    Kim, Seonghoon; Kolen, Michael J.

    2007-01-01

    Under item response theory, the characteristic curve methods (Haebara and Stocking-Lord methods) are used to link two ability scales from separate calibrations. The linking methods use their respective criterion functions that can be defined differently according to the symmetry- and distribution-related schemes. The symmetry-related scheme…

  7. Length-weight relationship and metric-meristic characteristics of two scorpion fishes (Scorpaena notata and Scorpaena porcus in İzmir Bay

    Directory of Open Access Journals (Sweden)

    Sencer Akalın

    2011-10-01

    Full Text Available In this study, 2 species (Scorpaena notata, Scorpaena porcus belong to Scorpaena genus were caught monthly by trawl surveys carried out between January 2005-July 2007 in İzmir Bay, in order to determine of morfometric and meristic characteristics and length-weigth relationships parameters. During the research period, 658 Scorpaena notata and 221 Scorpaena porcus indi¬viduals were investigated. The lenght-weight relationship of fishes were estimated as W=0.0164*L3.074 (r2=0.960 and W=0.0209*L2.987 (r=0.993 for Scorpaena notata and Scorpa¬ena porcus, respectively. As a result of student t-test (p<0.05, it was determined that the growth characteristics of S. notata and S. porcus are positive allometry and isometry respecti¬vely in the bay. In addition, 19 morphometric measurements taken and 7 meristic characteristic were counted for 23 S. notata and 29 S.porcus individuals.

  8. The Effect of Map Scale on the Determination of the Coastline Length and the Area of Islands in the Adriatic Sea - the Example of the Island of Rab

    OpenAIRE

    Nada Vučetić; Nedjeljko Frančula; Ivana Šimat

    2006-01-01

    The procedure to determine the coastline length and the area of the island of Rab from the maps at the scales 1:25 000, 1:50 000, 1:100 000, 1:200 000, 1:300 000, 1:500 000, 1:1 000 000 and 1:2 000 000 is described. The map sheets at the scales 1:25 000, 1:100 000 and 1:200 000 were obtained already in a georeferenced raster format, and the others were scanned and georeferenced. This was followed by a manual vectorization of the coastline and a transformation of all coordinates into the 5th z...

  9. Investigation of scaling characteristics for defining design environments due to transient ground winds and near-field, nonlinear acoustic fields

    Science.gov (United States)

    Shih, C. C.

    1973-01-01

    In order to establish a foundation of scaling laws for the highly nonlinear waves associated with the launch vehicle, the basic knowledge of the relationships among the paramaters pertinent to the energy dissipation process associated with the propagation of nonlinear pressure waves in thermoviscous media is required. The problem of interest is to experimentally investigate the temporal and spacial velocity profiles of fluid flow in a 3-inch open-end pipe of various lengths, produced by the propagation of nonlinear pressure waves for various diaphragm burst pressures of a pressure wave generator. As a result, temporal and spacial characteristics of wave propagation for a parametric set of nonlinear pressure waves in the pipe containing air under atmospheric conditions were determined. Velocity measurements at five sections along the pipes of up to 210 ft. in length were made with hot-film anemometers for five pressure waves produced by a piston. The piston was derived with diaphragm burst pressures at 20, 40, 60, 80 and 100 psi in the driver chamber of the pressure wave generator.

  10. The Electrostatic Screening Length in Concentrated Electrolytes Increases with Concentration

    OpenAIRE

    Smith, Alexander M.; Lee, Alpha A.; Perkin, Susan

    2016-01-01

    According to classical electrolyte theories interactions in dilute (low ion density) electrolytes decay exponentially with distance, with the Debye screening length the characteristic length-scale. This decay length decreases monotonically with increasing ion concentration, due to effective screening of charges over short distances. Thus within the Debye model no long-range forces are expected in concentrated electrolytes. Here we reveal, using experimental detection of the interaction betwee...

  11. Scaling between localization length and {Tc} in disordered YBa{sub 2}Cu{sub 3}O{sub 6.9}

    Energy Technology Data Exchange (ETDEWEB)

    Gauzzi, A.; Pavuna, D.

    1999-12-20

    The authors quantitatively study the effect of growth-induced reduction of long range structural order on the superconducting transition in epitaxial YBa{sub 2}Cu{sub 3}O{sub 6.9} films. The corresponding reduction of structural coherence length r{sub c} is determined from the width of X-ray diffraction rocking curves. {Tc} measurements in the films give evidence for the validity of the empirical scaling relation {Delta}{Tc} {approximately} r{sub c,ab}{sup {minus}2}, where {Delta}{Tc} is the disorder-induced reduction of {Tc} and r{sub c,ab} is the structural coherence length in the ab-plane. To explain this algebraic law the authors propose a simple phenomenological model based on the disorder-induced localization of the charge carriers within each ordered domain of size r{sub c,ab}. This picture enables them to precisely determine the Ginzburg-Landau superconducting coherence length in the ab-plane, and they obtain {xi}{sub ab} = 1.41 {+-} 0.04 nm.

  12. Ballistic behaviour on length scales exceeding 100μm in a GaAs/AlGaAs FET heterostructure

    International Nuclear Information System (INIS)

    Full text: Ballistic phenomena such as commensurability oscillations and electron focusing are well known in structures with dimensions of 10μm or less. We report the observation of ballistic electron transport in square GaAs/AlGaAs samples 100 μm wide: clear oscillations in van der Pauw type magnetoresistance measurements which correspond to electron focusing. Peak to valley ratios of the oscillations exceed 80 percent, indicating that mean free paths may be several times the width of the device. These mean free paths are attained in an enhancement-mode field-effect transistor system in which doping is not employed, with a corresponding diminution of disorder. Electron density is accurately tunable from below 1 x 1010 cm-2 to above 6 x 1011 cm-2. Interesting differences in electron characteristics between different subbands have been observed. The Dingle ratio (the ratio of scattering times τm/τSdH), where the scattering times are determined from the mobility and Shubnikov-de-Haas oscillations respectively) for the lowest subband is 35, while for the upper subband a value of 2.5 is obtained when the total electron density is 3.6 x 1011 cm-2

  13. The Effect of NaOH Concentration and Length of Transesterification Time on Characteristic of FAME from Reutealis trisperma (Kemiri Sunan

    Directory of Open Access Journals (Sweden)

    Sarifah Nurjanah

    2015-02-01

    Full Text Available Biodiesel (FAME is biofuel as a result from conversion process of triglycerides (oil into FAME (Fatty Acid Methyl Esther.  Reutelis trisperma (Kemiri Sunan is one of the plant that contains triglycerides, which is inedible oil due to its high poisonous component (alpha oleostearic acid, therefore this plant can be used as the nature source of biodiesel production.  The research aimed to study the effect of NaOH concentration and length of transesterification time on the yield and FAME characteristic.  The experiment was arranged in Completely Randomized Design with two replicated.  The result indicated that 0.75% NaOH in two hours transesterification  produce the highest yield of FAME with density 0.8703 g/cm3, kinematic viscosity 5.325 cSt, acid value 0.552 mg KOH/g and iodine value 46.6972 g I2/g.

  14. Phase Behavior of Blends of Linear and Branched Polyethylenes on Micron-Length Scales via Ultra-Small-Angle Neutron Scattering (USANS)

    Energy Technology Data Exchange (ETDEWEB)

    Agamalian, M M; Alamo, R G; Londono, J D; Mandelkern, L; Wignall, G D

    1999-05-17

    SANS experiments on blends of linear, high density (HD) and long chain branched, low density (LD) polyethylenes indicate that these systems form a one-phase mixture in the melt. However, the maximum spatial resolution of pinhole cameras is approximately equal to 103Å and it has therefore been suggested that data might also be interpreted as arising from a bi-phasic melt with large a particle size (~ 1 µm), because most of the scattering from the different phases would not be resolved. We have addressed this hypothesis by means of USANS experiments, which confirm that HDPEILDPE blends are homogenous in the melt on length scales up to 20 µm. We have also studied blends of HDPE and short-chain branched linear low density polyethylenes (LLDPEs), which phase separate when the branch content is sufficiently high. LLDPEs prepared with Ziegler-Natta catalysts exhibit a wide distribution of compositions, and may therefore be thought of as a "blend" of different species. When the composition distribution is broad enough, a fraction of highly branched chains may phase separate on µm-length scales, and USANS has also been used to quantify this phenomenon.

  15. Modeling the hydraulic characteristics of a fractured rock mass with correlated fracture length and aperture: Application in the underground research tunnel at KAERI

    International Nuclear Information System (INIS)

    A three-dimensional discrete fracture network model was developed in order to simulate the hydraulic characteristics of a granitic rock mass at Korea Atomic Energy Research Institute (KAERI) Underground Research Tunnel (KURT). The model N used a three-dimensional discrete fracture network (DFN), assuming a correlation between the length and aperture of the fractures, and a trapezoid flow path in the fractures. These assumptions that previous studies have not considered could make the developed model more practical and reasonable. The geologic and hydraulic data of the fractures were obtained in the rock mass at the KURT. Then, these data were applied to the developed fracture discrete network model. The model was applied in estimating the representative elementary volume (REV), the equivalent hydraulic conductivity tensors, and the amount of groundwater inflow into the tunnel. The developed discrete fracture network model can determine the REV size for the rock mass with respect to the hydraulic behavior and estimate the groundwater flow into the tunnel at the KURT. Therefore, the assumptions that the fracture length is correlated to the fracture aperture and the flow in a fracture occurs in a trapezoid shape appear to be effective in the DFN analysis used to estimate the hydraulic behavior of the fractured rock mass.

  16. The Smallest Valid Extension-Based Efficient, Rare Graph Pattern Mining, Considering Length-Decreasing Support Constraints and Symmetry Characteristics of Graphs

    Directory of Open Access Journals (Sweden)

    Unil Yun

    2016-05-01

    Full Text Available Frequent graph mining has been proposed to find interesting patterns (i.e., frequent sub-graphs from databases composed of graph transaction data, which can effectively express complex and large data in the real world. In addition, various applications for graph mining have been suggested. Traditional graph pattern mining methods use a single minimum support threshold factor in order to check whether or not mined patterns are interesting. However, it is not a sufficient factor that can consider valuable characteristics of graphs such as graph sizes and features of graph elements. That is, previous methods cannot consider such important characteristics in their mining operations since they only use a fixed minimum support threshold in the mining process. For this reason, in this paper, we propose a novel graph mining algorithm that can consider various multiple, minimum support constraints according to the types of graph elements and changeable minimum support conditions, depending on lengths of graph patterns. In addition, the proposed algorithm performs in mining operations more efficiently because it can minimize duplicated operations and computational overheads by considering symmetry features of graphs. Experimental results provided in this paper demonstrate that the proposed algorithm outperforms previous mining approaches in terms of pattern generation, runtime and memory usage.

  17. Differences in Starch Chain Length Distribution and Structure Characteristics of Early-Indica Rice Under Different Temperature Treatments During Grain Filling

    Institute of Scientific and Technical Information of China (English)

    ZHONG Lian-jin; CHENG Fang-min; ZHANG Guo-ping; SUN Zong-xiu

    2005-01-01

    Effects of temperature during grain-filling on chain length distribution and structure characteristics of 4 early-season indica rice cultivars were investigated under the environment-controlled conditions. The plants at flowering stage were subjected to two temperature treatments until maturity (the mean dairy air temperature, 22 and 32℃ for optimum temperature treatment and high temperature treatment, respectively). The result showed that high temperature during grain-filling significantly decreased the long B-chain content and increased the intermediate B-chain content. But the effect of high temperature on other starch chains appeared to be cultivar-dependant. The crystalline characteristics of rice starch were also affected by temperature during grain-filling. The intensity at 18° 2 θ of X-ray diffraction pattern of rice samples under high temperature was higher than those under optimum temperature, though all rice starches performed A-crystalline type. Moreover, the intensity at 18° 2 θ was positive correlation with intermediate B-chain content and negative correlation with long B-chain content.

  18. Study on the response characteristics of photomultiplier tubes measuring tens of milliseconds scale broad pulsed signals

    International Nuclear Information System (INIS)

    It has provided the origin of tens of milliseconds scale broad pulsed signal and discussed the reasons of photomultiplier tubes distortions. This thesis also gives the application background of this test. In order to get the response characteristics of the photomultiplier tubes measuring tens of milliseconds scale broad pulsed signals, it has built the broad signal test equipments. After that it has researched a method to restrain the response distortions of the photomultiplier tubes. What it has researched gives the basis for broad pulsed neutrons detector and provides the important references for broad pulsed neutrons detection. (authors)

  19. Screening for depressive disorders using the MASQ anhedonic depression scale: A receiver-operator characteristic analysis

    OpenAIRE

    Bredemeier, Keith; Spielberg, Jeffrey M; Silton, Rebecca Levin; Berenbaum, Howard; Heller, Wendy; Miller, Gregory A.

    2010-01-01

    The present study examined the utility of the anhedonic depression scale from the Mood and Anxiety Symptoms Questionnaire (MASQ-AD) as a way to screen for depressive disorders. Using receiver-operator characteristic analysis, the sensitivity and specificity of the full 22-item MASQ-AD scale, as well as the 8 and 14-item subscales, were examined in relation to both current and lifetime DSM-IV depressive disorder diagnoses in two nonpatient samples. As a means of comparison, the sensitivity and...

  20. A characteristic time scale of tick quotes on foreign currency markets

    CERN Document Server

    Sato, A H

    2005-01-01

    This study investigates that a characteristic time scale on an exchange rate market (USD/JPY) is examined for the period of 1998 to 2000. Calculating power spectrum densities for the number of tick quotes per minute and averaging them over the year yield that the mean power spectrum density has a peak at high frequencies. Consequently it means that there exist the characteristic scales which dealers act in the market. A simple agent model to explain this phenomenon is proposed. This phenomena may be a result of stochastic resonance with exogenous periodic information and physiological fluctuations of the agents. This may be attributed to the traders' behavior on the market. The potential application is both quantitative characterization and classification of foreign currency markets.

  1. Saturation of the two-plasmon decay instability in long-scale-length plasmas relevant to direct-drive inertial confinement fusion.

    Science.gov (United States)

    Froula, D H; Yaakobi, B; Hu, S X; Chang, P-Y; Craxton, R S; Edgell, D H; Follett, R; Michel, D T; Myatt, J F; Seka, W; Short, R W; Solodov, A; Stoeckl, C

    2012-04-20

    Measurements of the hot-electron generation by the two-plasmon-decay instability are made in plasmas relevant to direct-drive inertial confinement fusion. Density-scale lengths of 400 μm at n(cr)/4 in planar CH targets allowed the two-plasmon-decay instability to be driven to saturation for vacuum intensities above ~3.5×10(14) W cm(-2). In the saturated regime, ~1% of the laser energy is converted to hot electrons. The hot-electron temperature is measured to increase rapidly from 25 to 90 keV as the laser beam intensity is increased from 2 to 7×10(14) W cm(-2). This increase in the hot-electron temperature is compared with predictions from nonlinear Zakharov models. PMID:22680726

  2. Single-length-scaling analysis for antiferromagnetic fractons in dilute Heisenberg system RbMn0.4Mg0.6F3

    International Nuclear Information System (INIS)

    The dynamic structure factors S(q,w) of an ideal percolating network, the three-dimensional (3d) dilute Heisenberg antiferromagnet RbMn0.4Mg0.6F3, obtained from high resolution (ΔE = 17.5 (micro)eV) inelastic neutron scattering (INS) experiments are analyzed for the first time within the framework of the single-length-scaling postulate (SLSP). The analysis confirms the validity of the SLSP and is also used to extract the values of the key exponents governing the spin dynamics, the dynamic exponent (zAF = Df/tildedAF) being 2.5 ± 0.1 and the spectral dimension tildedAF for antiferromagnetic (AFM) fractons taking a value of unity.

  3. An adaptive strategy based on linear prediction of queue length to minimize congestion in Barabási—Albert scale-free networks

    International Nuclear Information System (INIS)

    In this paper, we propose an adaptive strategy based on the linear prediction of queue length to minimize congestion in Barabási—Albert (BA) scale-free networks. This strategy uses local knowledge of traffic conditions and allows nodes to be able to self-coordinate their accepting probability to the incoming packets. We show that the strategy can delay remarkably the onset of congestion and systems avoiding the congestion can benefit from hierarchical organization of accepting rates of nodes. Furthermore, with the increase of prediction orders, we achieve larger values for the critical load together with a smooth transition from free-flow to congestion. (interdisciplinary physics and related areas of science and technology)

  4. Modified Bose-Einstein and Fermi-Dirac statistics if excitations are localized on an intermediate length scale: Applications to non-Debye specific heat

    Science.gov (United States)

    Chamberlin, Ralph V.; Davis, Bryce F.

    2013-10-01

    Disordered systems show deviations from the standard Debye theory of specific heat at low temperatures. These deviations are often attributed to two-level systems of uncertain origin. We find that a source of excess specific heat comes from correlations between quanta of energy if excitations are localized on an intermediate length scale. We use simulations of a simplified Creutz model for a system of Ising-like spins coupled to a thermal bath of Einstein-like oscillators. One feature of this model is that energy is quantized in both the system and its bath, ensuring conservation of energy at every step. Another feature is that the exact entropies of both the system and its bath are known at every step, so that their temperatures can be determined independently. We find that there is a mismatch in canonical temperature between the system and its bath. In addition to the usual finite-size effects in the Bose-Einstein and Fermi-Dirac distributions, if excitations in the heat bath are localized on an intermediate length scale, this mismatch is independent of system size up to at least 106 particles. We use a model for correlations between quanta of energy to adjust the statistical distributions and yield a thermodynamically consistent temperature. The model includes a chemical potential for units of energy, as is often used for other types of particles that are quantized and conserved. Experimental evidence for this model comes from its ability to characterize the excess specific heat of imperfect crystals at low temperatures.

  5. Metric characteristics of Anxiety Scale for Children and Adolescents: A preliminary study

    Directory of Open Access Journals (Sweden)

    Ana Krevh

    2007-07-01

    Full Text Available The paper is exploring measurements of anxiety in youth and adolescence. It introduces a new scale for measuring anxiety in youth and adolescence (LAOM and selected metric characteristics are being analysed. The scale was designed to measure general level of anxiety in school surroundings. The concept of anxiety and the evolvement of measures are highlighted and the theoretical base for construction of the new scale is presented. The psychometric analyses were based on a sample of 300 elementary school children of both genders. The structure of the first version of LAOM was analysed with component analysis and the relevant items were kept. The reliability of the second version of the scale in terms of its internal consistency proved to be sufficient (Cronbach α = ,89. The scale differed between groups with different levels of anxiety. Concurrent validity was verified through a high positive correlation with translated STAI –X2 scale (Lamovec, 1988. Another evidence in favour of construct validity of the LAOM was provided with important gender and age differences.

  6. The Psychometric Characteristics of the Exercise Benefits/Barriers Scale among Iranian Elderly.

    Directory of Open Access Journals (Sweden)

    Ahmad Ali Akbari Kamrani

    2014-03-01

    Full Text Available The objective of this study was to investigate the validity and reliability of the Farsi version of the perceived benefits/barriers scale of physical activity in Iranian elderly.Overall, 388 elderly subjects (60 yr and over completed the demographic characteristics questionnaire, the Exercise Benefits/Barriers Scale (EBBS and the Yale physical activity scale. Data were analyzed through of exploratory factor analysis, using Varimax rotation, Cronbach's alpha and Pearson correlation.The matrix table of rotated elements of Farsi version of EBBS showed ten components, and 41 items predicted 61.83% of variance. 28 items in 5 components for benefits of, and 13 items in 5 components for barriers to physical activity were identified. Cronbach's alpha for internal consistency in the whole scale and its subscales was 0.83, 0.94 and 0.68. In addition, positive and significant correlation was found between overall benefits and their sub-scales as well as between overall barriers and their subscales. Moreover, there was significant and positive correlation between physical activity and the benefits (r=0.209, P=0.005 and significant negative correlation between physical activity and the barriers (r=-0.231, P=0.001.The results showed acceptable reliability and validity of the Farsi version of Exercise Benefits/Barriers Scale among Iranian elderly.

  7. Statistical characteristics of meso-scale vortex effects on the track of a tropical cyclone

    International Nuclear Information System (INIS)

    This paper examines initial meso-scale vortex effects on the motion of a tropical cyclone (TC) in a system where coexisting two components of TC and meso-scale vortices with a barotropic vorticity equation model. The initial meso-scale vortices are generated stochastically by employing Reinaud's method. The 62 simulations are performed and analysed in order to understand the statistical characteristics of the effects. Results show that the deflection of the TC track at t = 24 h induced by the initial meso-scale vortices ranges from 2 km to 37 km with the mean value of 13.4 km. A more significant deflection of the TC track can be reduced when several initial meso-scale vortices simultaneously appear in a smaller TC circulation area. It ranges from 22 km to 37 km with the mean value of 28 km, this fact implies that the initial meso-scale vortices-induced deflection may not be neglected sometimes. (geophysics, astronomy, and astrophysics)

  8. Patterning at the 10 nanometer length scale using a strongly segregating block copolymer thin film and vapor phase infiltration of inorganic precursors

    Science.gov (United States)

    Choi, Jonathan W.; Li, Zhaodong; Black, Charles T.; Sweat, Daniel P.; Wang, Xudong; Gopalan, Padma

    2016-06-01

    In this work, we demonstrate the use of self-assembled thin films of the cylinder-forming block copolymer poly(4-tert-butylstyrene-block-2-vinylpyridine) to pattern high density features at the 10 nm length scale. This material's large interaction parameter facilitates pattern formation in single-digit nanometer dimensions. This block copolymer's accessible order-disorder transition temperature allows thermal annealing to drive the assembly of ordered 2-vinylpyridine cylinders that can be selectively complexed with the organometallic precursor trimethylaluminum. This unique chemistry converts organic 2-vinylpyridine cylinders into alumina nanowires with diameters ranging from 8 to 11 nm, depending on the copolymer molecular weight. Graphoepitaxy of this block copolymer aligns and registers sub-12 nm diameter nanowires to larger-scale rectangular, curved, and circular features patterned by optical lithography. The alumina nanowires function as a robust hard mask to withstand the conditions required for patterning the underlying silicon by plasma etching. We conclude with a discussion of some of the challenges that arise with using block copolymers for patterning at sub-10 nm feature sizes.In this work, we demonstrate the use of self-assembled thin films of the cylinder-forming block copolymer poly(4-tert-butylstyrene-block-2-vinylpyridine) to pattern high density features at the 10 nm length scale. This material's large interaction parameter facilitates pattern formation in single-digit nanometer dimensions. This block copolymer's accessible order-disorder transition temperature allows thermal annealing to drive the assembly of ordered 2-vinylpyridine cylinders that can be selectively complexed with the organometallic precursor trimethylaluminum. This unique chemistry converts organic 2-vinylpyridine cylinders into alumina nanowires with diameters ranging from 8 to 11 nm, depending on the copolymer molecular weight. Graphoepitaxy of this block copolymer aligns and

  9. Scaling characteristics of depletion type, fully transparent amorphous indium-gallium-zinc-oxide thin-film transistors and inverters following Ar plasma treatment

    Science.gov (United States)

    Kim, Joonwoo; Jeong, Soon Moon; Jeong, Jaewook

    2015-11-01

    We fabricated depletion type, transparent amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs) and inverters with an Ar plasma treatment and analyzed their scaling characteristics with channel lengths ranging from 2 to 100 µm. The improvement of the field-effect mobility of a-IGZO TFTs is apparent only for short channel lengths. There is also an unexpected side effect of the Ar plasma treatment, which introduces back-channel interfacial states and induces a positive shift in the threshold voltage of a-IGZO TFTs. The resulting increase in the field-effect mobility and the positive shift in the threshold voltage of each TFT increase the differential gain up to 3 times and the positive shift in the transient point of the transparent inverters.

  10. The evolution of clustering length, large-scale bias and host halo mass at 2

    CERN Document Server

    Durkalec, A; Pollo, A; de la Torre, S; Cassata, P; Garilli, B; Brun, V Le; Lemaux, B C; Maccagni, D; Pentericci, L; Tasca, L A M; Thomas, R; Vanzella, E; Zamorani, G; Zucca, E; Amorin, R; Bardelli, S; Cassarà, L P; Castellano, M; Cimatti, A; Cucciati, O; Fontana, A; Giavalisco, M; Grazian, A; Hathi, N P; Ilbert, O; Paltani, S; Ribeiro, B; Schaerer, D; Scodeggio, M; Sommariva, V; Talia, M; Tresse, L; Vergani, D; Capak, P; Charlot, S; Contini, T; Cuby, J G; Dunlop, J; Fotopoulou, S; Koekemoer, A; Lopez-Sanjuan, C; Mellier, Y; Pforr, J; Salvato, M; Scoville, N; Taniguchi, Y; Wang, P W

    2014-01-01

    We investigate the evolution of galaxy clustering for galaxies in the redshift range 2.0<$z$<5.0 using the VIMOS Ultra Deep Survey (VUDS). We present the projected (real-space) two-point correlation function $w_p(r_p)$ measured by using 3022 galaxies with robust spectroscopic redshifts in two independent fields (COSMOS and VVDS-02h) covering in total 0.8 deg$^2$. We quantify how the scale dependent clustering amplitude $r_0$ changes with redshift making use of mock samples to evaluate and correct the survey selection function. Using a power-law model $\\xi(r) = (r/r_0)^{-\\gamma}$ we find that the correlation function for the general population is best fit by a model with a clustering length $r_0$=3.95$^{+0.48}_{-0.54}$ h$^{-1}$Mpc and slope $\\gamma$=1.8$^{+0.02}_{-0.06}$ at $z$~2.5, $r_0$=4.35$\\pm$0.60 h$^{-1}$Mpc and $\\gamma$=1.6$^{+0.12}_{-0.13}$ at $z$~3.5. We use these clustering parameters to derive the large-scale linear galaxy bias $b_L^{PL}$, between galaxies and dark matter. We find $b_L^{PL}$ =...

  11. A study of small-scale foliation in lengths of core enclosing fault zones in borehole WD-3, Permit Area D, Lac du Bonnet Batholith

    Energy Technology Data Exchange (ETDEWEB)

    Ejeckam, R.B.

    1992-12-01

    Small-scale foliation measurements in lengths of core from borehole WD-3 of Permit Area D of the Lac du Bonnet Batholith have defined five major mean orientation sets. They strike NW, N and NE. The orientations (strike to the left of the dip direction/dip) of these sets are as follows: Set I - 028/74 deg; II - 001/66 deg; III - 100/58 deg; IV - 076/83 deg; and V - 210/40 deg. The small-scale foliations were defined by different mineral types such as biotite crystals, plagioclase, mineral banding and quartz lenses. Well-developed biotite foliation is commonly present whenever well-developed plagioclase foliation exists, but as the strength of development weakens, the preferred orientations of plagioclase foliation do not correspond to those of biotite. It is also noted that the foliations appear to strike in directions orthogonal to the fractures in the fracture zones in the same depth interval. No significant change in foliation orientation was observed in Zones I to IV. Set V, however, whose mean orientation is 210/40 deg, is absent from the Zone IV interval, ranging from 872 to 905 m. (auth)

  12. Experimental study on the effect of fracture scale on seismic wave characteristics

    Institute of Scientific and Technical Information of China (English)

    Wei Jianxin; Di Bangrang; Wang Qiang

    2008-01-01

    In fractured reservoir beds,fracture characteristics affect seismic wave response.Fractured models based on the Hudson's fractured medium theory were constructed in our laboratory by a backfilling technique.For the same fracture density,the variations of the velocity and amplitude of the primary wave and shear wave parallel and perpendicular to the fracture were observed by altering the diameter (scale)of the penny-shaped fracture disk.The model test indicated that an increase of fracture scale increased the velocity and amplitude of the primary wave by about 2%.When the shear wave propagated parallel to the fracture,the velocity of the fast shear wave hardly changed,while the velocity of slow shear wave increased by 2.6% with increasing fracture scale.The results indicated that an increase of fracture scale would reduce the degree of anisotropy of the shear wave.The amplitudes of slow shear waves propagating parallel and perpendicular to fractures decreased with increasing fracture scale.

  13. Screening for Depressive Disorders Using the Mood and Anxiety Symptoms Questionnaire Anhedonic Depression Scale: A Receiver-Operating Characteristic Analysis

    Science.gov (United States)

    Bredemeier, Keith; Spielberg, Jeffery M.; Silton, Rebecca Levin; Berenbaum, Howard; Heller, Wendy; Miller, Gregory A.

    2010-01-01

    The present study examined the utility of the anhedonic depression scale from the Mood and Anxiety Symptoms Questionnaire (MASQ-AD scale) as a way to screen for depressive disorders. Using receiver-operating characteristic analysis, we examined the sensitivity and specificity of the full 22-item MASQ-AD scale, as well as the 8- and 14-item…

  14. Variations of characteristic time scales in rotating stratified turbulence using a large parametric numerical study.

    Science.gov (United States)

    Rosenberg, D; Marino, R; Herbert, C; Pouquet, A

    2016-01-01

    We study rotating stratified turbulence (RST) making use of numerical data stemming from a large parametric study varying the Reynolds, Froude and Rossby numbers, Re, Fr and Ro in a broad range of values. The computations are performed using periodic boundary conditions on grids of 1024(3) points, with no modeling of the small scales, no forcing and with large-scale random initial conditions for the velocity field only, and there are altogether 65 runs analyzed in this paper. The buoyancy Reynolds number defined as R(B) = ReFr2 varies from negligible values to ≈ 10(5), approaching atmospheric or oceanic regimes. This preliminary analysis deals with the variation of characteristic time scales of RST with dimensionless parameters, focusing on the role played by the partition of energy between the kinetic and potential modes, as a key ingredient for modeling the dynamics of such flows. We find that neither rotation nor the ratio of the Brunt-Väisälä frequency to the inertial frequency seem to play a major role in the absence of forcing in the global dynamics of the small-scale kinetic and potential modes. Specifically, in these computations, mostly in regimes of wave turbulence, characteristic times based on the ratio of energy to dissipation of the velocity and temperature fluctuations, T(V) and T(P), vary substantially with parameters. Their ratio γ=T(V)/T(P) follows roughly a bell-shaped curve in terms of Richardson number Ri. It reaches a plateau - on which time scales become comparable, γ≈0.6 - when the turbulence has significantly strengthened, leading to numerous destabilization events together with a tendency towards an isotropization of the flow. PMID:26830757

  15. Long length scales of element transport during reaction texture development in orthoamphibole-cordierite gneiss: Thor-Odin dome, British Columbia, Canada

    Science.gov (United States)

    Goergen, Eric T.; Whitney, Donna L.

    2012-02-01

    First-order factors controlling the textural and chemical evolution of metamorphic rocks are bulk composition and pressure-temperature-time ( P- T- t) path. Although it is common to assume that major element bulk composition does not change during regional metamorphism, rocks with reaction textures such as corona structures record evidence for major changes in effective bulk composition (EBC) and therefore provide significant insight into the scale, pathways, and mechanisms of element transport during metamorphism. Quantifying changes in EBC is essential for petrologic applications such as calculation of phase diagrams (pseudosections). The progressive growth of complex corona structures on garnet and Al2SiO5 porphyroblasts in orthoamphibole-cordierite gneiss Thor-Odin dome (British Columbia, Canada) reduced the EBC volume of the rock during metamorphism and therefore had a dramatic effect on the evolution of the stable mineral assemblage. These rocks contain a chemical and textural record of metamorphic reactions and preserve 3D networks (reaction pathways) connecting corona structures. These coronal networks record long (>cm) length scales of localized element transport during metamorphism. P- T, T- X, and P- X pseudosections are used to investigate the control of effective bulk composition on phase assemblage evolution. Despite textural complexity and evidence for disequilibrium, mineral assemblages and compositions were successfully modeled and peak metamorphic conditions estimated at 750°C and 9 kbar. These results illustrate how textural and chemical changes during metamorphism can be evaluated using an integrated petrographic and pseudosection approach, highlight the importance of effective bulk composition choice for application of phase equilibria methods in metamorphic rocks, and show how corona structures can be used to understand the scale of compositional change and element transport during metamorphism.

  16. CHARACTERISTICS OF ENTREPRENEURS: A COMPARATIVE STUDY OF SMALL SCALE ENTREPRENEURS OF SRILANKAN AND BANGLADESH

    Directory of Open Access Journals (Sweden)

    Nimalathasan B

    2008-10-01

    Full Text Available People are the most valuable resource within any country. There appears to be a strong linkage between the training, attitudes and goals of people and the level of economic growth within a country. An essential ingredient in the economic growth of any country is the key individual who promotes change and development, these persons may be called entrepreneurs. The Entrepreneurs are playing a major role in accelerating the pace of economic development the world over by their innovative and creative approach to the process of production and product launching in the market. They have thus helped to guide a new economic order by perception of new opportunities and converting them into profitable ventures. Hence various studies have been done on the above theme, but no studies have been conducted in SriLankan and Bangladesh perspectives, especially in Small Scale Entrepreneurs. Present study is initiated Characteristics of Entrepreneur, as a comparative study of Small Scale Entrepreneurs of SriLankan and Bangladesh with the samples of fifty (50. Factor analysis shows that SriLankan entrepreneurs have characteristics such as seeking opportunity, persistence, commitment to work contract, demand for work quality and efficiency, risk taking, visionary, similarly Bangladeshi entrepreneurs also have above characteristics except visionary.

  17. MMPI-2 Symptom Validity (FBS) Scale: psychometric characteristics and limitations in a Veterans Affairs neuropsychological setting.

    Science.gov (United States)

    Gass, Carlton S; Odland, Anthony P

    2014-01-01

    The Minnesota Multiphasic Personality Inventory-2 (MMPI-2) Symptom Validity (Fake Bad Scale [FBS]) Scale is widely used to assist in determining noncredible symptom reporting, despite a paucity of detailed research regarding its itemmetric characteristics. Originally designed for use in civil litigation, the FBS is often used in a variety of clinical settings. The present study explored its fundamental psychometric characteristics in a sample of 303 patients who were consecutively referred for a comprehensive examination in a Veterans Affairs (VA) neuropsychology clinic. FBS internal consistency (reliability) was .77. Its underlying factor structure consisted of three unitary dimensions (Tiredness/Distractibility, Stomach/Head Discomfort, and Claimed Virtue of Self/Others) accounting for 28.5% of the total variance. The FBS's internal structure showed factoral discordance, as Claimed Virtue was negatively related to most of the FBS and to its somatic complaint components. Scores on this 12-item FBS component reflected a denial of socially undesirable attitudes and behaviors (Antisocial Practices Scale) that is commonly expressed by the 1,138 males in the MMPI-2 normative sample. These 12 items significantly reduced FBS reliability, introducing systematic error variance. In this VA neuropsychological referral setting, scores on the FBS have ambiguous meaning because of its structural discordance. PMID:24826489

  18. Upscaling analysis of aerodynamic roughness length based on in situ data at different spatial scales and remote sensing in north Tibetan Plateau

    Science.gov (United States)

    Sun, Genhou; Hu, Zeyong; Wang, Jiemin; Xie, Zhipeng; Lin, Yun; Huang, Fangfang

    2016-07-01

    The aerodynamic roughness length (z0m) is a crucial parameter in quantifying momentum, sensible and latent heat fluxes between land surface and atmosphere, and it depends greatly on spatial scales. This paper presents a tentative study on the upscaling analysis of z0m in the north Tibetan Plateau based on in situ data from eddy covariance (EC) and large aperture scintillometer (LAS) and leaf area index (LAI) of MODerate-resolution Imaging Spectroradiometer (MODIS) with 250 m and 2 km spatial resolutions. The comparison of z0m calculated from EC (z0m_EC) and LAS (z0m _LAS) data indicates that z0m at both scales has apparent seasonal variations and is in good agreement with the LAI result. However, z0m_LAS is higher than z0m_EC, which is attributed to the differences in roughness elements in their footprints. An upscaling relationship for z0m is developed with z0m_EC, z0m _LAS and LAI with 250 m spatial resolution of MODIS. In addition, an altitude correction factor is introduced into the vegetation height estimation equation because the cold environment in the north Tibetan Plateau, which is due to its high altitude, has a strong influence on vegetation height. The z0m retrieval with 250 m spatial resolution in the rain season is validated with z0m_EC at sites Nagqu/Amdo, Nagqu/MS3478 and Nagqu/NewD66, and the agreement is acceptable. The spatial distribution of z0m retrievals at small spatial scale in the north Tibetan Plateau from June to September 2012 shows that the z0m values are less than 0.015 m in most areas, with the exception of the area in the southeast part, where z0m reaches 0.025 m owing to low altitudes. The z0m retrievals at large spatial scale in the north Tibetan Plateau from June to September 2012 range from 0.015 to 0.065 m, and high values appear in the area with low altitudes. The spatial distribution and frequency statistics of z0m retrievals at both spatial scales reveal the influence of altitude and LAI on the z0m in the north Tibetan

  19. Perceived characteristics of the environment associated with active travel: development and testing of a new scale

    Directory of Open Access Journals (Sweden)

    Mutrie Nanette

    2008-05-01

    Full Text Available Abstract Background Environmental characteristics may be associated with patterns of physical activity. However, the development of instruments to measure perceived characteristics of the local environment is still at a comparatively early stage, and published instruments are not necessarily suitable for application in all settings. We therefore developed and established the test-retest reliability of a new scale for use in a study of the correlates of active travel and overall physical activity in deprived urban neighbourhoods in Glasgow, Scotland. Methods We developed and piloted a 14-item scale based on seven constructs identified from the literature (aesthetics, green space, access to amenities, convenience of routes, traffic, road safety and personal safety. We administered the scale to all participants in a random postal survey (n = 1322 and readministered the scale to a subset of original respondents (n = 125 six months later. We used principal components analysis and Varimax rotation to identify three principal components (factors and derived summary scores for subscales based on these factors. We examined the internal consistency of these subscales using Cronbach's alpha and examined the test-retest reliability of the individual items, the subscale summary scores and an overall summary neighbourhood score using a combination of correlation coefficients and Cohen's kappa with and without weighting. Results Public transport and proximity to shops were the items most likely to be rated positively, whereas traffic volume, traffic noise and road safety for cyclists were most likely to be rated negatively. Three principal components – 'safe and pleasant surroundings', 'low traffic' and 'convenience for walking' – together explained 45% of the total variance. The test-retest reliability of individual items was comparable with that of items in other published scales (intraclass correlation coefficients (ICCs 0.34–0.70; weighted Cohen

  20. Circulational characteristics of a natural circulation circuit of a weakly boiling reactor large-scale model

    International Nuclear Information System (INIS)

    A large-scale model for determining circulational characteristics of a natural circulation circuit of weakly boiling (core outlet steam content below 4%) tank tpype water cooled reactors is described. The model consists of 61 elecrtroheated fuel elements 14 mm in-diameter and 3 m height. Outlet pressure can vary within 1.7-5.0 MPa inlet water subcooling is 20-90 deg C, weight outlet balance steam content from-9 to 3.2 %. Results of the experiments performed for checking the algorithms developed for thermohydraulic calculation of steady-state characteristics of the investigated circuit are given. It is concluded that for one-phase coolant estimated and experimental values for pressure head and hydraulic resistance agree well with

  1. Dynamic Performance Characteristic Tests of Real Scale Lead Rubber Bearing for the Evaluation of Performance Criteria

    International Nuclear Information System (INIS)

    Dynamic characteristic tests of full scale lead rubber bearing were performed for the evaluation of performance criteria of isolation system for nuclear power plants. For the dynamic test for a full scale rubber bearing, two 1500mm diameter lead rubber bearings were manufactured. The viewpoints of this dynamic test are determination of an ultimate shear strain level of lead rubber bearing, behavior of rubber bearing according to static and dynamic input motion, sinusoidal and random (earthquake) motion, and 1-dimentional and 2-dimensional input motion. In this study, seismic isolation device tests were performed for the evaluation of performance criteria of isolation system. Through this test, it can be recognized that in the case of considering a mechanical property test, dynamic and multi degree of loading conditions should be determined. But these differences should be examined how much affect to the global structural behavior

  2. Trends and characteristics observed in nuclear events based on international nuclear event scale reports

    International Nuclear Information System (INIS)

    The International Nuclear Event Scale (INES) is jointly operated by the IAEA and the OECD-NEA as a means designed for providing prompt, clear and consistent information related to nuclear events, that occurred at nuclear facilities, and facilitating communication between the nuclear community, the media and the public. Nuclear events are reported to the INES with the Scale', a consistent safety significance indicator, which runs from level 0, for events with no safety significance, to level 7 for a major accident with widespread health and environmental effects. Since the operation of INES was initiated in 1990, approximately 500 events have been reported and disseminated. The present paper discusses the trends observed in nuclear events, such as overall trends of the reported events and characteristics of safety significant events with level 2 or higher, based on the INES reports. (author)

  3. Geostatistical and Fractal Characteristics of Soil Moisture Patterns from Plot to Catchment Scale Datasets

    Science.gov (United States)

    Korres, Wolfgang; Reichenau, Tim G.; Fiener, Peter; Koyama, Christian N.; Bogena, Heye R.; Cornelissen, Thomas; Baatz, Roland; Herbst, Michael; Diekkrüger, Bernd; Vereecken, Harry; Schneider, Karl

    2016-04-01

    Soil moisture and its spatio-temporal pattern is a key variable in hydrology, meteorology and agriculture. The aim of the current study is to analyze spatio-temporal soil moisture patterns of 9 datasets from the Rur catchment (Western Germany) with a total area of 2364 km², consisting of a low mountain range (forest and grassland) and a loess plain dominated by arable land. Data was acquired across a variety of land use types, on different spatial scales (plot to mesoscale catchment) and with different methods (field measurements, remote sensing, and modelling). All datasets were analyzed using the same methodology. In a geostatistical analysis sill and range of the theoretical variogram were inferred. Based on this analysis, three groups of datasets with similar characteristics in the autocorrelation structure were identified: (i) modelled and measured datasets from a forest sub-catchment (influenced by soil properties and topography), (ii) remotely sensed datasets from the cropped part of the total catchment (influenced by the land-use structure of the cropped area), and (iii) modelled datasets from the cropped part of the Rur catchment (influenced by large scale variability of soil properties). A fractal analysis revealed that soil moisture patterns of all datasets show a multi-fractal behavior (varying fractal dimensions, patterns are only self-similar over certain ranges of scales), with at least one scale break and generally high fractal dimensions (high spatial variability). Corresponding scale breaks were found in various datasets and the factors explaining these scale breaks are consistent with the findings of the geostatistical analysis. The joined analysis of the different datasets showed that small differences in soil moisture dynamics, especially at maximum porosity and wilting point in the soils, can have a large influence on the soil moisture patterns and their autocorrelation structure.

  4. Scaling of H-mode pedestal characteristics in DIII-D and C-Mod

    International Nuclear Information System (INIS)

    Since the H-mode edge pedestal effectively sets the boundary conditions for energy transport throughout the core, a better understanding of the pedestal region is necessary in order to fully predict H-mode performance. Pedestal characteristics in the DIII-D and Alcator C-Mod tokamaks are described, and scalings of the pedestal width with various plasma parameters are shown. The pedestal width in both tokamaks varies in an inverse sense with plasma current, and is independent of toroidal field. Other similarities, as well as differences, are discussed. It is also found that the pedestal widths of the various physical quantities involved (Te, Ti, ne, ni) may be different. (author)

  5. LiDAR measurements of full scale wind turbine wake characteristics

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose; Larsen, Gunner Chr.; Mann, Jakob; Enevoldsen, Karen

    Full scale wind speed measurements, recorded inside the wake of an operating 2MW/80m wind turbine,has been performed during the spring 2009, as part of the EU-TOPFARM project. Longitudinal wind speeds in wake cross sections are measured with a LiDAR system mounted in the rear of the nacelle. The...... experimental setup, the amount of data, preliminary analysis and limitations of using LIDAR measurements to identify the wake dynamics will be presented. Resolving the wake in the meandering frame of reference further allows for identification of the wake characteristics both in terms of wake deficit and wake...

  6. LiDAR measurements of full scale wind turbine wake characteristics

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose; Larsen, Gunner Chr.; Mann, Jakob;

    2009-01-01

    Full scale wind speed measurements, recorded inside the wake of an operating 2MW/80m wind turbine,has been performed during the spring 2009, as part of the EU-TOPFARM project. Longitudinal wind speeds in wake cross sections are measured with a LiDAR system mounted in the rear of the nacelle. The...... experimental setup, the amount of data, preliminary analysis and limitations of using LIDAR measurements to identify the wake dynamics will be presented. Resolving the wake in the meandering frame of reference further allows for identification of the wake characteristics both in terms of wake deficit and wake...

  7. Enhanced gypsum scaling by organic fouling layer on nanofiltration membrane: Characteristics and mechanisms.

    Science.gov (United States)

    Wang, Jiaxuan; Wang, Lei; Miao, Rui; Lv, Yongtao; Wang, Xudong; Meng, Xiaorong; Yang, Ruosong; Zhang, Xiaoting

    2016-03-15

    To investigate how the characteristics of pregenerated organic fouling layers on nanofiltration (NF) membranes influence the subsequent gypsum scaling behavior, filtration experiments with gypsum were carried out with organic-fouled poly(piperazineamide) NF membranes. Organic fouling layer on membrane was induced by bovine serum albumin (BSA), humic acid (HA), and sodium alginate (SA), respectively. The morphology and components of the scalants, the role of Ca(2+) adsorption on the organic fouling layer during gypsum crystallization, and the interaction forces of gypsum on the membrane surface were investigated. The results indicated that SA- and HA-fouled membranes had higher surface crystallization tendency along with more severe flux decline during gypsum scaling than BSA-fouled and virgin membranes because HA and SA macromolecules acted as nuclei for crystallization. Based on the analyses of Ca(2+) adsorption onto organic adlayers and adhesion forces, it was found that the flux decline rate and extent in the gypsum scaling experiment was positively related to the Ca(2+)-binding capacity of the organic matter. Although the dominant gypsum scaling mechanism was affected by coupling physicochemical effects, the controlling factors varied among foulants. Nevertheless, the carboxyl density of organic matter played an important role in determining surface crystallization on organic-fouled membrane. PMID:26799710

  8. Psychometric characteristics of the scale for assessment of the risk of children and juveniles for conflict with the law

    OpenAIRE

    Marčetić-Radunović Gordana; Hrnčić Jasna; Žegarac Nevenka

    2013-01-01

    Growing needs of our experts for operative and relevant tool for risk assessment of children and adolescents in conflict with the law initiated construction of the Scale for Assessment of the Risk of Children and Juveniles for Conflict with the Law (Risk Scale). This paper presents results of research aiming on assessment of psychometric characteristics of the Scale and its applicability by experts in centres for social work (CSW). Scale has 72 items organi...

  9. Milti-scaled studies of watershed characteristics within the Tongass National Forest, Southeast Alaska

    Science.gov (United States)

    Edwards, R. T.; D'Amore, D. V.; Hood, E.; Fellman, J. B.; Norberg, E. C.; Biles, F. E.

    2005-12-01

    The Tongass National Forest (Tongass), in Southeast Alaska, is the largest temperate maritime, rainforest in North America. It covers an area of 68,798 km2, stretches over 6 degrees of latitude, encompasses over 5,000 anadramous salmon reaches, and includes over 70 ecoregions, associated with several major geologic terranes. Wetlands dominate this wet region, comprising about 30% of terrestrial area. The region is currently experiencing climate change with potentially profound impacts on wetland soil processes, forest structure, stream productivity and the large and valuable salmon fishery. Because of the size and remoteness of the forest, there are little data on stream chemistry, biological productivity, or discharge. To better predict the impacts of climate change, forest practices, or land use change on stream productivity, we require much better baseline data on naturally occurring variability in watershed and stream characteristics and the major biophysical drivers that control stream biogeochemistry. Our efforts to develop a systematic understanding of watershed types and responses include studies at three spatial, temporal and organizational scales. One study is aimed at developing a process-based understanding of how major wetland and vegetation types influence stream chemistry, particularly dissolved organic carbon, through hydrologic coupling and carbon, nitrogen and phosphorus transport. This study is restricted to paired or longitudinal watershed studies with intense sampling frequency and a broad array of detailed measurements. Costs are high and the generality of the results are implied but not confirmed. A second study, of intermediate temporal and spatial scale seeks to identify broader patterns in stream chemistry among three common Tongass stream types within the vicinity of Juneau, Alaska: glacial, brownwater and clearwater. This study has confirmed that these broad stream classes respond differently on a seasonal basis but provides no

  10. Addition of low concentrations of an ionic liquid to a base oil reduces friction over multiple length scales: a combined nano- and macrotribology investigation.

    Science.gov (United States)

    Li, Hua; Somers, Anthony E; Howlett, Patrick C; Rutland, Mark W; Forsyth, Maria; Atkin, Rob

    2016-03-01

    The efficacy of ionic liquids (ILs) as lubricant additives to a model base oil has been probed at the nanoscale and macroscale as a function of IL concentration using the same materials. Silica surfaces lubricated with mixtures of the IL trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate and hexadecane are probed using atomic force microscopy (AFM) (nanoscale) and ball-on-disc tribometer (macroscale). At both length scales the pure IL is a much more effective lubricant than hexadecane. At the nanoscale, 2.0 mol% IL (and above) in hexadecane lubricates the silica as well as the pure IL due to the formation of a robust IL boundary layer that separates the sliding surfaces. At the macroscale the lubrication is highly load dependent; at low loads all the mixtures lubricate as effectively as the pure IL, whereas at higher loads rather high concentrations are required to provide IL like lubrication. Wear is also pronounced at high loads, for all cases except the pure IL, and a tribofilm is formed. Together, the nano- and macroscales results reveal that the IL is an effective lubricant additive - it reduces friction - in both the boundary regime at the nanoscale and mixed regime at the macroscale. PMID:26865399

  11. The seasonal and solar cycle variations of electron density gradient scale length, vertical drift and layer height during magnetically quiet days: Implications for Spread F over Trivandrum, India

    Science.gov (United States)

    Manju, G.; Devasia, C. V.; Ravindran, S.

    2009-12-01

    A study has been carried out on the behaviour of electron density gradient scale length, L, vertical drift and layer height, around post sunset hours, during the magnetically quiet days of summer, winter and equinox seasons of solar maximum (2002) and minimum years (1995), using ionosonde data of Trivandrum (8.5°N, 76.5°E, dip = 0.5°N) in the Indian longitude sector. The results indicate a clear seasonal and solar cycle variation in all the three parameters. Further, the seasonal variation of equatorial Spread F (ESF) during the above period is examined in terms of the relative roles of L, the vertical drift and layer height (of the F layer) in the triggering of the collisional Rayleigh-Taylor instability. The results, show for the first time, that L also plays an important role, in controlling the quiet time seasonal and solar cycle variability of ESF; whereas in earlier studies this parameter had been taken to be constant. The detailed results are presented and discussed.

  12. Derivation of effective fission gas diffusivities in UO2 from lower length scale simulations and implementation of fission gas diffusion models in BISON

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Anders David Ragnar [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pastore, Giovanni [Idaho National Lab. (INL), Idaho Falls, ID (United States); Liu, Xiang-Yang [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Perriot, Romain Thibault [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tonks, Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Stanek, Christopher Richard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-11-07

    This report summarizes the development of new fission gas diffusion models from lower length scale simulations and assessment of these models in terms of annealing experiments and fission gas release simulations using the BISON fuel performance code. Based on the mechanisms established from density functional theory (DFT) and empirical potential calculations, continuum models for diffusion of xenon (Xe) in UO2 were derived for both intrinsic conditions and under irradiation. The importance of the large XeU3O cluster (a Xe atom in a uranium + oxygen vacancy trap site with two bound uranium vacancies) is emphasized, which is a consequence of its high mobility and stability. These models were implemented in the MARMOT phase field code, which is used to calculate effective Xe diffusivities for various irradiation conditions. The effective diffusivities were used in BISON to calculate fission gas release for a number of test cases. The results are assessed against experimental data and future directions for research are outlined based on the conclusions.

  13. Orbital and Physical Characteristics of Meter-scale Impactors from Airburst Observations

    CERN Document Server

    Brown, P; Clark, D; Tagliaferri, E

    2015-01-01

    We have analysed the orbits and ablation characteristics in the atmosphere of 59 earth-impacting fireballs, produced by meteoroids one meter in diameter or larger, described here as meter-scale. Using heights at peak luminosity as a proxy for strength, we determine that there is roughly an order of magnitude spread in strengths of the population of meter-scale impactors at the Earth. We use fireballs producing recovered meteorites and well documented fireballs from ground-based camera networks to calibrate our ablation model interpretation of the observed peak height of luminosity as a function of speed. The orbits and physical strength of these objects are consistent with the majority being asteroidal bodies originating from the inner main asteroid belt. We find a lower limit of ~10-15% of our objects have a possible cometary (Jupiter-Family comet and/or Halley-type comet) origin based on orbital characteristics alone. Only half this number, however, also show evidence for weaker than average structure. Two ...

  14. Influence of Aromatic Residues on the Material Characteristics of Aβ Amyloid Protofibrils at the Atomic Scale.

    Science.gov (United States)

    Chang, Hyun Joon; Baek, Inchul; Lee, Myeongsang; Na, Sungsoo

    2015-08-01

    Amyloid fibrils, which cause a number of degenerative diseases, are insoluble under physiological conditions and are supported by native contacts. Recently, the effects of the aromatic residues on the Aβ amyloid protofibril were investigated in a ThT fluorescence study. However, the relationship between the material characteristics of the Aβ protofibril and its aromatic residues has not yet been investigated on the atomic scale. Here, we successfully constructed wild-type (WT) and mutated types of Aβ protofibrils by using molecular dynamics simulations. Through principle component analysis, we established the structural stability and vibrational characteristics of F20L Aβ protofibrils and compared them with WT and other mutated models such as F19L and F19LF20L. In addition, structural stability was assessed by calculating the elastic modulus, which showed that the F20L model has higher values than the other models studied. From our results, it is shown that aromatic residues influence the structural and material characteristics of Aβ protofibrils. PMID:26037071

  15. Performance and slipstream characteristics of small-scale propellers at low Reynolds numbers

    Science.gov (United States)

    Deters, Robert W.

    The low Reynolds number effects of small-scale propellers were investigated. At the Reynolds numbers of interest (below 100,000), a decrease in lift and an increase in drag is common making it difficult to predict propeller performance characteristics. A propeller testing apparatus was built to test small scale propellers in static conditions and in an advancing flow. Twenty-seven off-the-shelf propellers, with diameters ranging from 2.25 in to 9 in, were tested in order to determine the general effects of low Reynolds numbers on small propellers. From these tests, increasing the Reynolds number for a propeller increases its efficiency by either increasing the thrust produced or decreasing the power. By doubling the Reynolds number of a propeller, it is not uncommon to increase the efficiency by more the 10%. Using off-the-shelf propellers limits the geometry available and finding propellers of the same geometry but of different scale is very difficult. To solve this problem, four propellers were design and built using a 3D printer. Two of the propellers were simple rectangular twisted blades of different chords. Another propeller was modeled after a full-scale propeller. The fourth propeller was created using inverse design to minimize power loss. Each propeller was built in a 5-in and 9-in diameter version in order to test a larger range of Reynolds numbers. A separate propeller blade and hub system was created to allow each propeller to be tested with different pitch angles and to test each propeller in a 2-, 3-, and 4-blade version. From the performance results of the 3D printed propellers, it was shown that propellers of different scale, but tested at the same Reynolds number, had about the same performance results. Finally, the slipstreams of different propellers were measured using a 7-hole probe. Propeller slipstreams can have a large effect on the aerodynamics of lifting surfaces downstream of the propeller. Small UAVs and MAVs flying in close proximity

  16. Spatial distribution pattern, scale and gap characteristics of Pinus armandii population in Qinling Mountains, China

    Institute of Scientific and Technical Information of China (English)

    LAN Guoyu; CHEN Wei; LEI Ruide

    2007-01-01

    Based on the data collected from 27 plots of the Pinus armandii community in Qinling Mountains,we studied the spatial distribution pattern,scale,and gap characteristics of the P.armandii population.The results showed that the population had a clumped distribution before age 50.At the age range from 15 to 25,though the population tended to be distributed randomly,the distribution was still clumped.The population distribution at the age range from 40 to 50 was at the transitional stage from clumped to random.After age 50,the population started to be senesced,the distribution pattern turning from clumped to random.The distribution pattern scale of P.armandii always changes with the development stage of the population,being 100 m2 in general.The gap size of P armandii population was similar to its distribution pattem scale,and the gaps of 80-130 m2 occupied 59% of the total.Because of the better light and nutrient condition in the gap,P.armandii seedlings grew well,which helped the population keep its stability through "mobile mosaic circling".

  17. The influence of the violation of scaling in the different regions of X on the γ-families characteristics

    International Nuclear Information System (INIS)

    Some characteristics of γ-families simulated with the models of scaling in the fragmentation region are considered. It is investigated the dependence of some γ-families characteristics on 1) the speed of inccrease of production cross-sectionn 2) the composition of primary cosmic rays and 3) their energy spectrum; 4) the width of the part of pionization region where scaling is violated

  18. Orbital and physical characteristics of meter-scale impactors from airburst observations

    Science.gov (United States)

    Brown, P.; Wiegert, P.; Clark, D.; Tagliaferri, E.

    2016-03-01

    We have analyzed the orbits and ablation characteristics in the atmosphere of 59 Earth-impacting fireballs, produced by meteoroids 1 m in diameter or larger, described here as meter-scale. Using heights at peak luminosity as a proxy for strength, we determine that there is roughly an order of magnitude spread in strengths of the population of meter-scale impactors at the Earth. We use fireballs producing recovered meteorites and well documented fireballs from ground-based camera networks to calibrate our ablation model interpretation of the observed peak height of luminosity as a function of speed. The orbits and physical strength of these objects are consistent with the majority being asteroidal bodies originating from the inner main asteroid belt. This is in contrast to earlier suggestions by Ceplecha (Ceplecha, Z. [1994]. Astron. Astrophys. 286, 967-970) that the majority of meter-tens of meter sized meteoroids are "… cometary bodies of the weakest known structure". We find a lower limit of ∼10-15% of our objects have a possible cometary (Jupiter-Family comet and/or Halley-type comet) origin based on orbital characteristics alone. Only half this number, however, also show evidence for weaker than average structure. Two events, Sumava and USG 20131121, have exceptionally high (relative to the remainder of the population) heights of peak brightness. These are physically most consistent with high microporosity objects, though both were on asteroidal-type orbits. We also find three events, including the Oct 8, 2009 airburst near Sulawesi, Indonesia, which display comparatively low heights of peak brightness, consistent with strong monolithic stones or iron meteoroids. Based on orbital similarity, we find a probable connection among several events in our population with the Taurid meteoroid complex; no other major meteoroid streams show probable linkages to the orbits of our meter-scale population. Our impactors cover almost four orders of magnitude in mass, but

  19. Footprint Characteristics Revised for Field-Scale Soil Moisture Monitoring with Cosmic-Ray Neutrons

    CERN Document Server

    Köhli, M; Zreda, M; Schmidt, U; Dietrich, P; Zacharias, S

    2016-01-01

    Cosmic-ray neutron probes are widely used to monitor environmental water content near the surface. The method averages over tens of hectares and is unrivaled in serving representative data for agriculture and hydrological models at the hectometer scale. Recent experiments, however, indicate that the sensor response to environmental heterogeneity is not fully understood. Knowledge of the support volume is a prerequisite for the proper interpretation and validation of hydrogeophysical data. In a previous study, several physical simplifications have been introduced into a neutron transport model in order to derive the characteristics of the cosmic-ray probe's footprint. We utilize a refined source and energy spectrum for cosmic-ray neutrons and simulate their response to a variety of environmental conditions. Results indicate that the method is particularly sensitive to soil moisture in the first tens of meters around the probe, whereas the radial weights are changing dynamically with ambient water. The footprin...

  20. Synthesis and characteristics of large-scale ZnO rods by wet chemical method

    Institute of Scientific and Technical Information of China (English)

    WEI Su-feng; JIANG Qing; LIAN Jian-she

    2008-01-01

    The large-scale ZnO rods of submicrometer were prepared on the bare glass using a wet chemical method under different experimental parameters, such as the reactant concentration and the growth time. The microstructure of the ZnO rods was characterized by X-ray diffractometry(XRD) and field emission scanning electron microscopy (FESEM) with the energy dispersive X-ray spectroscopy(EDX), and the optical property was investigated by the room-temperature photoluminescence (PL) spectra. XRD and FESEM results show that the wurtzite structure and rod-like ZnO is obtained. The length (3-8 μm) and the diameter (400 nm- 3 μm) vary with the experimental parameters. A strong UV emission at 384 nm and a weak visible yellow-green emission around 570 nm are observed in the PL spectrum. After annealing at 600 ℃ in air, the UV peak intensity increases obviously and the yellow-green peak intensity decreases greatly. The near-band-edge UV emission is attributed to the exciton recombination; the yellow-green emission can be associated with the defect recombination; and some defect complexes may be responsible for the latter emission.

  1. Effects of magnetic order on the superconducting length scales and critical fields in single crystal ErNi2B2C

    DEFF Research Database (Denmark)

    Gammel, P.L.; Barber, B.P.; Ramirez, A.P.;

    1999-01-01

    The flux line form factor in small angle neutron scattering and transport data determines the superconducting length scares and critical fields in single crystal ErNi2B2C. For H parallel to c, the coherence length xi increases and the penetration depth lambda decreases when crossing T-N = 6.0 K, ...

  2. Dynamic Concept of Returns to Scales and Its Characteristics on Production Frontier in Intersection Form

    Institute of Scientific and Technical Information of China (English)

    Quan-ling Wei; Hong Yan

    2011-01-01

    This paper gives a dynamic concept and a new non-parametric method for evaluating returns to scale (RTS) of economic units with multiple inputs and outputs. It is frequently noticed that when we increase the input of a decision making unit (DMU) with a certain status of RTS, different status of RTS is observed. For example, when we increase the input of a DMU with constant RTS under the traditional method, a decreasing RTS is often observed instead of the expected constant RTS. We thus define the RTS of each DMU in both input expansion and contraction regions respectively. The research starts from transferring the production possibility set into the intersection form, by giving the explicit linear inequality representation of production frontiers. The RTS structural characteristics of DMUs' on the production frontier are described. Status of RTS of those DMUs on the production frontier include increasing RTS, constant RTS, decreasing RTS, saturated RTS and evidence of congestion. Necessary and sufficient conditions for RTS evaluation are provided. The definition and evaluation method given here provide more detailed economic characteristics of DMU for policy makers.

  3. Evaporation characteristics of thin film liquid argon in nano-scale confinement: A molecular dynamics study

    Science.gov (United States)

    Hasan, Mohammad Nasim; Shavik, Sheikh Mohammad; Rabbi, Kazi Fazle; Haque, Mominul

    2016-07-01

    Molecular dynamics simulation has been carried out to explore the evaporation characteristics of thin liquid argon film in nano-scale confinement. The present study has been conducted to realize the nano-scale physics of simultaneous evaporation and condensation inside a confined space for a three phase system with particular emphasis on the effect of surface wetting conditions. The simulation domain consisted of two parallel platinum plates; one at the top and another at the bottom. The fluid comprised of liquid argon film at the bottom plate and vapor argon in between liquid argon and upper plate of the domain. Considering hydrophilic and hydrophobic nature of top and bottom surfaces, two different cases have been investigated: (i) Case A: Both top and bottom surfaces are hydrophilic, (ii) Case B: both top and bottom surfaces are hydrophobic. For all cases, equilibrium molecular dynamics (EMD) was performed to reach equilibrium state at 90 K. Then the lower wall was set to four different temperatures such as 110 K, 120 K, 130 K and 140 K to perform non-equilibrium molecular dynamics (NEMD). The variation of temperature and density as well as the variation of system pressure with respect to time were closely monitored for each case. The heat fluxes normal to top and bottom walls were estimated and discussed to illuminate the effectiveness of heat transfer in both hydrophilic and hydrophobic confinement at various boundary temperatures of the bottom plate.

  4. Performance Characteristic Test of Scale Model Lead Rubber Bearings for NPP

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Kyu; Kim, Jung Han; Choi, Inkil [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    The seismic isolation device already applied to the conventional buildings and bridges. Even there are 6 nuclear power plant unit already applied seismic isolation system in France and South Africa. Although the seismic isolation device was already used in NPP but after the Fukushima accident it seems more important than before against earthquake. For applying to an NPP, the isolation system should have enough performance capacity because the safety criteria of nuclear power plants are much higher than that of conventional structure. For the development of performance criteria of isolation system for nuclear power plant, a scale model isolation device tests were performed in this paper. For the characteristic test, 20 scale model isolation devices were manufactured and basic mechanical property test and dynamic tests were performed. In this study, seismic isolation device tests were performed for the evaluation of performance criteria of isolation system. Through this test, it can be recognized that in the case of considering a mechanical property test, dynamic and multi degree of loading conditions should be determined. But these differences should be examined how much affect to the global structural behavior.

  5. Performance Characteristic Test of Scale Model Lead Rubber Bearings for NPP

    International Nuclear Information System (INIS)

    The seismic isolation device already applied to the conventional buildings and bridges. Even there are 6 nuclear power plant unit already applied seismic isolation system in France and South Africa. Although the seismic isolation device was already used in NPP but after the Fukushima accident it seems more important than before against earthquake. For applying to an NPP, the isolation system should have enough performance capacity because the safety criteria of nuclear power plants are much higher than that of conventional structure. For the development of performance criteria of isolation system for nuclear power plant, a scale model isolation device tests were performed in this paper. For the characteristic test, 20 scale model isolation devices were manufactured and basic mechanical property test and dynamic tests were performed. In this study, seismic isolation device tests were performed for the evaluation of performance criteria of isolation system. Through this test, it can be recognized that in the case of considering a mechanical property test, dynamic and multi degree of loading conditions should be determined. But these differences should be examined how much affect to the global structural behavior

  6. An 8 hour characteristic time-scale in submillimetre light curves of Sagittarius A*

    CERN Document Server

    Dexter, Jason; Bower, Geoffrey C; Marrone, Daniel P; Stone, Jordan; Plambeck, Richard; Doeleman, Sheperd S

    2013-01-01

    We compile and analyse long term (~10 year) submillimetre (1.3, 0.87, 0.43 mm, submm) wavelength light curves of the Galactic centre black hole, Sagittarius A*. The 0.87 and 0.43 mm data are taken from the literature, while the majority of the 1.3 mm light curve is from previously unpublished SMA and CARMA data. We use Monte Carlo simulations to show that on minute to few hour time-scales the variability is consistent with a red noise process with a 230 GHz power spectrum slope of 2.3+0.8-0.6 at 95% confidence. The light curve is de-correlated (white noise) on very long (month to year) times. In order to identify the transition time between red and white noise, we model the light curves as a stochastic damped random walk process. The models allow a quantitative estimate of this physical characteristic time-scale of 8-4+3 hours at 230 GHz at 95% confidence, with consistent results at 345 and 690 GHz. This corresponds to ~10 orbital times or ~1 inflow (viscous) time at R = 3 Rs, a typical radius producing the 2...

  7. Research on Spectral Reflection Characteristics of Nanostructures in Morpho Butterfly Wing Scale

    Energy Technology Data Exchange (ETDEWEB)

    Wu Wenjun [Key Lab of Modern Manufacture Quality Engineering, Hubei University of Technology, Wuhan, Hubei, 30068 (China); Shi Tielin; Liao Guanglan; Zuo Haibo, E-mail: guanglan.liao@mail.hust.edu.cn [State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, 430074 (China)

    2011-02-01

    The intricate nanostructure in the scales of Morpho, which is composed of transparent cuticle protein, achieves an extremely high reflectivity in the range of visible light. The brilliant iridescent blue color is not produced by blue pigment but nanostructures. In order to investigate which structural parameters influenced the spectral reflection characteristics and formed the striking brilliance of blue color, a vector diffraction theoretical structural model was established, and simulation using rigorous coupled-wave analysis was carried out. The complex nanostructure was assumed as the diffraction grating structure of arbitrary configuration. The shape and size of the model was set according to the TEM photos of Morpho scale. The structure with irregular asymmetric multilayer lamellae ridge-like grating possessed best capability in reflectivity and color matching. The influence of every structural parameter to spectral reflectivity was cognized by comparing with the original spectrum. The results have revealed the nature of iridescent blue colors and high reflectivity, and enable us to control color and reflectivity by manufacturing nanostructure with specific structural parameter.

  8. Characteristic Scales of Baryon Acoustic Oscillations from Perturbation Theory: Non-linearity and Redshift-Space Distortion Effects

    OpenAIRE

    Nishimichi, Takahiro; Ohmuro, Hiroshi; Nakamichi, Masashi; Taruya, Atsushi; Yahata, Kazuhiro; Shirata, Akihito; Saito, Shun; Nomura, Hidenori; Yamamoto, Kazuhiro; Suto, Yasushi

    2007-01-01

    An acoustic oscillation of the primeval photon-baryon fluid around the decoupling time imprints a characteristic scale in the galaxy distribution today, known as the baryon acoustic oscillation (BAO) scale. Several on-going and/or future galaxy surveys aim at detecting and precisely determining the BAO scale so as to trace the expansion history of the universe. We consider nonlinear and redshift-space distortion effects on the shifts of the BAO scale in $k$-space using perturbation theory. Th...

  9. Measurement of Thermal Lens Focal Length and Its Effect on Laser Output Characteristics in LD End-pumped Nd∶YVO4 Lasers

    Institute of Scientific and Technical Information of China (English)

    WAN Chunming(万春明); WANG Hui(王慧)

    2002-01-01

    According to the resonator transform circle theory, the focal length of thermal lens of laser media in laser diode end-pumped solid-state lasers is analyzed and measured with a simple method. A 30W 808nm LD pumped YVO4 laser is developed and characterized.

  10. Evaluation of hydraulic characteristics in a pilot-scale constructed wetland using a multi-tracer experiment

    Science.gov (United States)

    Birkigt, Jan; Stumpp, Christine; Małoszewski, Piotr; Richnow, Hans H.; Nijenhuis, Ivonne

    2013-04-01

    In recent years, constructed wetland systems have become into focus as means for organic contaminant removal. The use of constructed wetlands as part of water treatment offers great opportunities to realize significant savings in future wastewater treatment costs for small communities and the adaptation of large wastewater treatment plants. Wetland systems provide a highly reactive environment in which several elimination pathways of organic chemicals may be present at the same time; however, these elimination processes and hydraulic conditions are usually poorly understood. Previously, in our study site monochlorobenzene removal was observed in a pilot-scale wetland system which treats contaminated groundwater from the regional aquifer in Bitterfeld. The degradation was linked to either aerobic or anaerobic, iron- or sulfate- reduction or multiple processes, in parallel. However, it was unclear how the groundwater flows through this system, precluding a more founded understanding of the flow and transport processes. Therefore, we investigated the flow system in this three dimensional pilot-scale constructed wetland applying a multi tracer test combined with a mathematical model to evaluate the hydraulic characteristics. The pilot system consisted of a 6 m length x 1 m wide x 0.5 m depth gravel filter with a triple inflow distributed evenly approx. 5 cm from the bottom at the inflow. Three conservative tracers (uranine, bromide and deuterium) were injected as a pulse at the inflow and analyzed at 4 meters distance from the inflow at three different depths to obtain residence time distributions of groundwater flow in the gravel bed of the wetland. A mathematical multi-flow dispersion model was used to model the tracer breakthrough curves of the different sampling levels, which assumes parallel combinations of the one-dimensional advection-dispersion equation. The model was successfully applied to fit the experimental tracer breakthrough curves by assuming three flow

  11. Improving squeeze scale inhibitor adsorption and flow back characteristics with surfactants

    OpenAIRE

    Delon Jimenez, Paula

    2014-01-01

    The most common method for preventing downhole scale deposition is by the use of a scale inhibitor in a scale squeeze treatment. The process consists of injecting a scale inhibitor down a producer well into the near wellbore formation. It is believed that a change in the rock wettability will enhance the scale inhibitor adsorption to the rock, hence increasing the treatment lifetime. This master thesis discusses the effect of a surfactant preflush on scale inhibitor lifetime and also flow bac...

  12. Synoptic-scale characteristics and atmospheric controls of summer heat waves in China

    Science.gov (United States)

    Wang, Weiwen; Zhou, Wen; Li, Xiuzhen; Wang, Xin; Wang, Dongxiao

    2016-05-01

    Summer heat waves with persistent extreme high temperatures have been occurring with increasing frequency in recent decades. These extreme events have disastrous consequences for human health, economies, and ecosystems. In this study, we examine three summers with intense and protracted heat waves: the summers of 2003, 2006, and 2013, with high temperatures located mainly in southeastern, southwestern, and eastern China, respectively. The synoptic-scale characteristics of these heat waves and associated atmospheric circulation anomalies are investigated. In the early heat wave episode of 2003, a heat center was located in the southeast coastal provinces during the first 20 days of July. The maximum southward displacement of the East Asian jet stream (EAJS) induced anticyclonic anomalies to the south, associated with southwestward intensification of the western North Pacific subtropical high (WNPSH), and extreme high temperatures were found only to the south of the Yangtze River. In the later episode, a poleward displacement of the EAJS and an enhanced WNPSH over the midlatitudes of eastern China resulted in a "heat dome" over the region, and the heat wave extended northward to cover a larger area of eastern China. The coupling between the westward-enhanced WNPSH and poleward-displaced EAJS was found in the East China heat wave of 2013 as well. But the area of high temperatures reached far to the north in August 2013, with below-normal temperatures located in a small region of South China. In the 2006 southwestern drought and heat wave, extreme poleward displacement of the EAJS, associated with extraordinary westward extension of the WNSPH, resulted in further blocking of the moisture supply from the southwest monsoon. Large-scale moisture deficiencies, dry conditions, and downslope winds were common features of all investigated heat wave episodes. But in 2006, low-level heat lows associated with a well-mixed layer due to intensive daytime heating and atmospheric

  13. Large-scale collection and analysis of full-length cDNAs from Brachypodium distachyon and integration with Pooideae sequence resources.

    Directory of Open Access Journals (Sweden)

    Keiichi Mochida

    Full Text Available A comprehensive collection of full-length cDNAs is essential for correct structural gene annotation and functional analyses of genes. We constructed a mixed full-length cDNA library from 21 different tissues of Brachypodium distachyon Bd21, and obtained 78,163 high quality expressed sequence tags (ESTs from both ends of ca. 40,000 clones (including 16,079 contigs. We updated gene structure annotations of Brachypodium genes based on full-length cDNA sequences in comparison with the latest publicly available annotations. About 10,000 non-redundant gene models were supported by full-length cDNAs; ca. 6,000 showed some transcription unit modifications. We also found ca. 580 novel gene models, including 362 newly identified in Bd21. Using the updated transcription start sites, we searched a total of 580 plant cis-motifs in the -3 kb promoter regions and determined a genome-wide Brachypodium promoter architecture. Furthermore, we integrated the Brachypodium full-length cDNAs and updated gene structures with available sequence resources in wheat and barley in a web-accessible database, the RIKEN Brachypodium FL cDNA database. The database represents a "one-stop" information resource for all genomic information in the Pooideae, facilitating functional analysis of genes in this model grass plant and seamless knowledge transfer to the Triticeae crops.

  14. The Scale for Rating the Behavioral Characteristics of Gifted and Talented Students: Study of Factor Structure, Reliability and Validity

    OpenAIRE

    ŞAHİN, Feyzullah

    2014-01-01

    Th is study aims to develop a nomination scale that helps primary class teachers assessthe possible gift ed and talented students in their classes with their behavioral characteristics.Within this scope, validity check and reliability analysis studies were done.Th e study was fulfi lled based on descriptive survey model. As a result of the validitycheck of the Scale for Rating the Behavioral Characteristics of the Gift ed and TalentedStudents (SRBCGTS), it was realized that the gift ed and ta...

  15. Aerodynamic characteristics of a large-scale hybrid upper surface blown flap model having four engines

    Science.gov (United States)

    Carros, R. J.; Boissevain, A. G.; Aoyagi, K.

    1975-01-01

    Data are presented from an investigation of the aerodynamic characteristics of large-scale wind tunnel aircraft model that utilized a hybrid-upper surface blown flap to augment lift. The hybrid concept of this investigation used a portion of the turbofan exhaust air for blowing over the trailing edge flap to provide boundary layer control. The model, tested in the Ames 40- by 80-foot Wind Tunnel, had a 27.5 deg swept wing of aspect ratio 8 and 4 turbofan engines mounted on the upper surface of the wing. The lift of the model was augmented by turbofan exhaust impingement on the wind upper-surface and flap system. Results were obtained for three flap deflections, for some variation of engine nozzle configuration and for jet thrust coefficients from 0 to 3.0. Six-component longitudinal and lateral data are presented with four engine operation and with the critical engine out. In addition, a limited number of cross-plots of the data are presented. All of the tests were made with a downwash rake installed instead of a horizontal tail. Some of these downwash data are also presented.

  16. Effect of nano-scale characteristics of graphene on electrochemical performance of activated carbon supercapacitor electrodes

    Science.gov (United States)

    Jasni, M. R. M.; Deraman, M.; Suleman, M.; Hamdan, E.; Sazali, N. E. S.; Nor, N. S. M.; Shamsudin, S. A.

    2016-02-01

    Graphene with its typical nano-scale characteristic properties has been widely used as an additive in activated carbon electrodes in order to enhance the performance of the electrodes for their use in high performance supercapacitors. Activated carbon monoliths (ACMs) electrodes have been prepared by carbonization and activation of green monoliths (GMs) of pre-carbonized fibers of oil palm empty fruit bunches or self-adhesive carbon grains (SACGs) and SACGs added with 6 wt% of KOH-treated multi-layer graphene. ACMs electrodes have been assembled in symmetrical supercapacitor cells that employed aqueous KOH electrolyte (6 M). The cells have been tested with cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge discharge methods to investigate the effect of graphene addition on the specific capacitance (Csp), specific energy (E), specific power (P), equivalent series resistance (ESR) and response time (τo) of the supercapacitor cells. The results show that the addition of graphene in the GMs change the values of Csp, Emax, Pmax, ESR and τo from (61-96) F/g, 2 Wh/kg, 104 W/kg, 2.6 Ω and 38 s, to the respective values of (110-124) F/g, 3 Wh/kg, 156 W/kg, 3.4 Ω and 63 s. This study demonstrates that the graphene addition in the GMs has a significant effect on the electrochemical behavior of the electrodes.

  17. Footprint characteristics revised for field-scale soil moisture monitoring with cosmic-ray neutrons

    Science.gov (United States)

    Köhli, M.; Schrön, M.; Zreda, M.; Schmidt, U.; Dietrich, P.; Zacharias, S.

    2015-07-01

    Cosmic-ray neutron probes are widely used to monitor environmental water content near the surface. The method averages over tens of hectares and is unrivaled in serving representative data for agriculture and hydrological models at the hectometer scale. Recent experiments, however, indicate that the sensor response to environmental heterogeneity is not fully understood. Knowledge of the support volume is a prerequisite for the proper interpretation and validation of hydrogeophysical data. In a previous study, several physical simplifications have been introduced into a neutron transport model in order to derive the characteristics of the cosmic-ray probe's footprint. We utilize a refined source and energy spectrum for cosmic-ray neutrons and simulate their response to a variety of environmental conditions. Results indicate that the method is particularly sensitive to soil moisture in the first tens of meters around the probe, whereas the radial weights are changing dynamically with ambient water. The footprint radius ranges from 130 to 240 m depending on air humidity, soil moisture, and vegetation. The moisture-dependent penetration depth of 15 to 83 cm decreases exponentially with distance to the sensor. However, the footprint circle remains almost isotropic in complex terrain with nearby rivers, roads or hill slopes. Our findings suggest that a dynamically weighted average of point measurements is essential for accurate calibration and validation. The new insights will have important impact on signal interpretation, sensor installation, data interpolation from mobile surveys, and the choice of appropriate resolutions for data assimilation into hydrological models.

  18. The Method of Characteristics for 2-D Multigroup and Pointwise Transport Calculations in SCALE/CENTRM

    International Nuclear Information System (INIS)

    SCALE 6 computes problem-dependent multigroup (MG) cross sections through a combination of the conventional Bondarenko shielding-factor method and a deterministic pointwise (PW) transport calculation of the fine-structure spectra in the resolved resonance and thermal energy ranges. The PW calculation is performed by the CENTRM code using a 1-D cylindrical Wigner-Seitz model with the white boundary condition instead of the real rectangular cell shape to represent a lattice unit cell. The pointwise fluxes computed by CENTRM are not exact because a 1-D model is used for the transport calculation, which introduces discrepancies in the MG self-shielded cross sections, resulting in some deviation in the eigenvalue. In order to solve this problem, the method of characteristics (MOC) has been applied to enable the CENTRM PW transport calculation for a 2-D square pin cell. The computation results show that the new BONAMI/CENTRM-MOC procedure produces very precise self-shielded cross sections compared to MCNP reaction rates.

  19. Evaluation of hydraulic characteristics of a pilot-scale air-lift internal-loop bioreactor.

    Science.gov (United States)

    Abbas, Ghulam; Wang, Lan; Zhang, Hongtao; Zheng, Ping; Li, Wei; Zhang, Meng; Zeb, Bibi Saima; Zhang, Jiqiang

    2015-01-01

    Using sodium fluoride as tracer, residence time distribution technique was employed to evaluate the hydraulic characteristics of a pilot-scale Internal-Loop Airlift Bio-particle (ILAB) bioreactor that was a novel system for ammonia removal from wastewater. The results showed that the flow pattern of ILAB reactor was close to completely mixed reactor under all the tested air flow rates and liquid flow rates (with average N of 1.88). The total dead zone (TDZ) was 32.43% with biological dead zone (BDZ) of 20.66% and hydraulic dead zone (HDZ) of 8.95%. At higher air flow rates, the flow pattern of reactor approached that of completely mixed reactor (N from 2.72 to 1.54), and the increase of air flow rate gave rise to the decrease of TDZ in the reactor (from 36.24% to 23.00%). Whereas at higher liquid flow rates, the flow pattern of ILAB reactor got away from that of completely mixed reactor (N from 1.51 to 1.72), and the increase of liquid flow rate yielded a rise of TDZ in the reactor (from 28.48% to 36.84%). The study highlighted that the effect of air flow rate on flow pattern and TDZ of the reactor was greater than that of liquid flow rate. PMID:25594127

  20. Understanding I/O workload characteristics of a Peta-scale storage system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Youngjae [ORNL; Gunasekaran, Raghul [ORNL

    2015-01-01

    Understanding workload characteristics is critical for optimizing and improving the performance of current systems and software, and architecting new storage systems based on observed workload patterns. In this paper, we characterize the I/O workloads of scientific applications of one of the world s fastest high performance computing (HPC) storage cluster, Spider, at the Oak Ridge Leadership Computing Facility (OLCF). OLCF flagship petascale simulation platform, Titan, and other large HPC clusters, in total over 250 thousands compute cores, depend on Spider for their I/O needs. We characterize the system utilization, the demands of reads and writes, idle time, storage space utilization, and the distribution of read requests to write requests for the Peta-scale Storage Systems. From this study, we develop synthesized workloads, and we show that the read and write I/O bandwidth usage as well as the inter-arrival time of requests can be modeled as a Pareto distribution. We also study the I/O load imbalance problems using I/O performance data collected from the Spider storage system.

  1. Tracking Particulate Organic Matter Characteristics in Major Arctic Rivers: Indicators of Watershed-Scale Climate Impacts

    Science.gov (United States)

    McClelland, J. W.; Griffin, C. G.; Holmes, R. M.; Peterson, B. J.; Raymond, P. A.; Spencer, R. G.; Striegl, R. G.; Tank, S. E.

    2015-12-01

    Six large rivers, including the Yukon and Mackenzie in North America and the Yenisey, Ob', Lena, and Kolyma in Eurasia, drain the majority of the watershed area surrounding the Arctic Ocean. Parallel sampling programs were initiated at downstream locations on these rivers in 2003 to improve estimates of fluvial export and track large-scale perturbations associated with climate change. Over a decade later, synthesis of water chemistry data from these ongoing sampling efforts provides an unprecedented opportunity to 1) examine similarities and differences among the major Arctic rivers, and 2) think critically about how changes in various water chemistry parameters may or may not inform us about climate change impacts. River-borne organic matter characteristics may be particularly telling because mass flux values and composition/source indicators vary with hydrology and permafrost coverage. However, separating climate impacts that occur within river corridors from those that occur beyond them may be difficult, especially when considering changes in particulate organic matter (POM) loads. Data on suspended POM yields, C:N ratios, stable isotope ratios, and radiocarbon content in the major Arctic rivers show marked spatial, seasonal, and interannual variability that is helpful for thinking about how climate change effects may manifest in the future, but it will be challenging to separate changes in POM related to bank erosion and suspension/deposition of in situ sediment stocks from changes in POM that may be linked to processes such as permafrost thaw occurring across the broader landscape.

  2. Three-Dimensional Simulation of SOFC Anode Polarization Characteristics Based on Sub-Grid Scale Modeling of Microstructure

    OpenAIRE

    Kishimoto, Masashi; Iwai, Hiroshi; Saito, Motohiro; Yoshida, Hideo

    2012-01-01

    Three-dimensional numerical analysis of solid oxide fuel cell (SOFC) anode polarization is conducted with a microstructure obtained by a focused ion beam and scanning electron microscope (FIB-SEM). Electronic, ionic and gaseous transports with electrochemical reaction are considered in the porous anode. A sub-grid scale (SGS) model is newly developed and effectively used to consider the structural information whose characteristic scale is smaller than calculation grid size. The proposed SGS m...

  3. Abridgment of nano and micro length scale mechanical properties of novel Mg–9Li–7Al–1Sn and Mg–9Li–5Al–3Sn–1Zn alloys using object oriented finite element modeling

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Ankur [Department of Materials Science and Engineering, Indian Institute of Technology, Kanpur 208016 (India); Advanced Materials Processing and Analysis Center, Department of Materials Science and Engineering, University of Central Florida, Orlando, FL 32826 (United States); Kumar, Vinod [Department of Materials Science and Engineering, Indian Institute of Technology, Kanpur 208016 (India); Department of Metallurgical and Materials Engineering, Malaviya National Institute of Technology, Jaipur 302017 (India); Nair, Jitin [Department of Materials and Metallurgical Engineering, National Institute of Foundry and Forge Technology, Ranchi 834003 (India); Bansal, Ankit [Department of Materials Science and Engineering, Indian Institute of Technology, Kanpur 208016 (India); Tata Steel Ltd., Jamshedpur, Jharkhand 831001 (India); Balani, Kantesh, E-mail: kbalani@iitk.ac.in [Department of Materials Science and Engineering, Indian Institute of Technology, Kanpur 208016 (India)

    2015-06-15

    Highlights: • Dual phase (α + β) Mg–9Li–7Al–1Sn (LAT971) and Mg–9Li–5Al–3Sn–1Zn (LATZ9531) alloys. • Effective elastic modulus estimated from finite element method (FEM). • Correlation of nanoscale mechanical data with microstress distribution. • Precipitates of Mg–Al–Li act as stress relaxer and Mg–Li–Sn as stress concentrator. • Higher local heterogeneous stress distribution (∼0.6–5.7 GPa) in LATZ9531 alloys. - Abstract: In the recent years, magnesium–lithium (Mg–Li) alloys have attracted considerable attention/interest due to their high strength-to-density ratio and damping characteristic; and have found potential use in structural and biomedical applications. Here the mechanical behavior of novel Mg–9 wt.% Li–7 wt.% Al–1 wt.% Sn (LAT971) and Mg–9 wt.% Li–5 wt.% Al–3 wt.% Sn–1 wt.% Zn (LATZ9531) alloys is reported. Both, as cast and thermomechanically processed alloys have been studied which possess dual phase microstructure. Nanoindentation data have been utilized to envisage the elastic modulus of alloy via various micromechanics models (such as rule of mixtures, Voigt–Reuss, Cox model, Halpin–Tsai and Guth model) in order to estimate the elastic modulus. Object oriented finite element modeling (FEM) has been performed to predict stress distribution under tensile and compressive strain state. Close match between Halpin–Tsai model and FEM results show the abridgment of nano length scale property to evolution of microscopic stress distribution in novel LAT971 and LATZ9531 Mg–Li–Al based alloys.

  4. Reducing the item number to obtain the same-length self-assessment scales: a systematic approach using result of graphical loglinear rasch models

    DEFF Research Database (Denmark)

    Nielsen, Tine; Kreiner, Svend

    2011-01-01

    approach to item reduction based on results of graphical loglinear Rasch modeling (GLLRM) was designed. This approach was then used to reduce the number of items in the subscales of the R-D-LSI which had an item-length of more than seven items, thereby obtaining the Danish Self-Assessment Learning Styles...

  5. A Scaling Research on Faculty Characteristics That Higher Education Students Prioritize

    Science.gov (United States)

    Güvendir, Meltem Acar

    2014-01-01

    In view of the importance of taking student preferences into account while establishing educational practices, this study explores which faculty member characteristic fourth year students mostly prefer in a higher education institution. A faculty member characteristics form that includes ten characteristics was administered to 419 fourth year…

  6. Reliability and Characteristics of Wafer-Level Chip-Scale Packages under Current Stress

    Science.gov (United States)

    Chen, Po-Ying; Kung, Heng-Yu; Lai, Yi-Shao; Hsiung Tsai, Ming; Yeh, Wen-Kuan

    2008-02-01

    In this work, we present a novel approach and method for elucidating the characteristics of wafer-level chip-scale packages (WLCSPs) for electromigration (EM) tests. The die in WLCSP was directly attached to the substrate via a soldered interconnect. The shrinking of the area of the die that is available for power, and the solder bump also shrinks the volume and increases the density of electrons for interconnect efficiency. The bump current density now approaches to 106 A/cm2, at which point the EM becomes a significant reliability issue. As known, the EM failure depends on numerous factors, including the working temperature and the under bump metallization (UBM) thickness. A new interconnection geometry is adopted extensively with moderate success in overcoming larger mismatches between the displacements of components during current and temperature changes. Both environments and testing parameters for WLCSP are increasingly demanded. Although failure mechanisms are considered to have been eliminated or at least made manageable, new package technologies are again challenging its process, integrity and reliability. WLCSP technology was developed to eliminate the need for encapsulation to ensure compatibility with smart-mount technology (SMT). The package has good handing properties but is now facing serious reliability problems. In this work, we investigated the reliability of a WLCSP subjected to different accelerated current stressing conditions at a fixed ambient temperature of 125 °C. A very strong correlation exists between the mean time to failure (MTTF) of the WLCSP test vehicle and the mean current density that is carried by a solder joint. A series of current densities were applied to the WLCSP architecture; Black's power law was employed in a failure mode simulation. Additionally, scanning electron microscopy (SEM) was adopted to determine the differences existing between high- and low-current-density failure modes.

  7. Full-scale horizontal cable-tray tests: Fire-propagation characteristics

    International Nuclear Information System (INIS)

    At the Fermi National Accelerator Center (Fermilab), as at any high-energy physics laboratory, the experimental program depends on complex arrays of equipment that require years to assemble and place in service. These equipment arrays are typically located in enclosed tunnels or experimental halls and could be destroyed by rapidly propagating, uncontrolled fire. Cable trays, both vertical and horizontal, are an integral and ubiquitous component of these installations. Concurrently, throughout industry and within the professional fire-fighting community, there has been concern over the flammability and fire propagation characteristics of electrical cables in open cable trays. While some information was available concerning fire propagation in vertical cable trays, little was known about fires in horizontal cable trays. In view of the potential for loss of equipment and facilities, not to mention the programmatic impact of a fire, Fermilab initiated a program of full-scale, horizontal cable-tray fire tests to determine the flammability and rate of horizontal fire propagation in cable-tray configurations and cable mixed typical of those existing in underground tunnel enclosures and support buildings as Fermilab. This series of tests addressed the effects of ventilation rates and cable-tray fill, fire-fighting techniques, and the effectiveness and value of automatic sprinklers, smoke detection, and cable-coating fire barriers in detecting, controlling, or extinguishing a cable-tray fire. Detailed descriptions of each fire test, including sketches of cable-tray configuration and contents, instrumentation, ventilation rates, Fermilab Fire Department personnel observations, photographs, and graphs of thermocouple readings are available in a report of these tests prepared by the Fermilab Safety Section

  8. Psychometric characteristics of the scale for assessment of the risk of children and juveniles for conflict with the law

    Directory of Open Access Journals (Sweden)

    Marčetić-Radunović Gordana

    2013-01-01

    Full Text Available Growing needs of our experts for operative and relevant tool for risk assessment of children and adolescents in conflict with the law initiated construction of the Scale for Assessment of the Risk of Children and Juveniles for Conflict with the Law (Risk Scale. This paper presents results of research aiming on assessment of psychometric characteristics of the Scale and its applicability by experts in centres for social work (CSW. Scale has 72 items organized in nine subscales. Research included 65 subjects from 11 to 20 years of age, assessed by the Scale by 32 experts from nine municipality’s CSW in Serbia. Scale as a whole and its five subscales have good reliability. Two second order factors were extracted: Risks to the child/young person and Environmental risks that have acceptable reliability and good criteria validity in relation to Scale of Antisocial Behaviour Chronicity. Experts assessed that Scale is useful in practice and most of them didn’t have any difficulties in its application. Qualitative analysis of the result provided guidelines for further improvement of the Risk scale and for more comprehensive education of experts it the area. [Projekat Ministarstva nauke Republike Srbije, br. 47011: Kriminal u Srbiji - fenomenologija, rizici i mogućnosti socijalne intervencije

  9. An Outlook on Agricultural Modernization Path with Chinese Characteristics from Scale Agricultural Operation

    OpenAIRE

    WANG, Wanjiang

    2015-01-01

    First of all, this paper discusses the scale agricultural operation of China from the aspects of practical exploration and rational thinking. Later, it puts forward the concept of further promoting scale agricultural operation according to the present conditions of China, which includes encouraging large household pattern and scale breeding, developing various forms of socialized agricultural services, promoting agriculture industrialization, accelerating regional distribution of advantageous...

  10. Construction of a high-density genetic map based on large-scale markers developed by specific length amplified fragment sequencing (SLAF-seq) and its application to QTL analysis for isoflavone content in Glycine max

    OpenAIRE

    Li, Bin; Tian, Ling; Zhang, Jingying; Huang, Long; Han, Fenxia; Yan, Shurong; Wang, Lianzheng; Zheng, Hongkun; Sun, Junming

    2014-01-01

    Background Quantitative trait locus (QTL) mapping is an efficient approach to discover the genetic architecture underlying complex quantitative traits. However, the low density of molecular markers in genetic maps has limited the efficiency and accuracy of QTL mapping. In this study, specific length amplified fragment sequencing (SLAF-seq), a new high-throughput strategy for large-scale SNP discovery and genotyping based on next generation sequencing (NGS), was employed to construct a high-de...

  11. The Electrostatic Screening Length in Concentrated Electrolytes Increases with Concentration.

    Science.gov (United States)

    Smith, Alexander M; Lee, Alpha A; Perkin, Susan

    2016-06-16

    According to classical electrolyte theories interactions in dilute (low ion density) electrolytes decay exponentially with distance, with the Debye screening length the characteristic length scale. This decay length decreases monotonically with increasing ion concentration due to effective screening of charges over short distances. Thus, within the Debye model no long-range forces are expected in concentrated electrolytes. Here we reveal, using experimental detection of the interaction between two planar charged surfaces across a wide range of electrolytes, that beyond the dilute (Debye-Hückel) regime the screening length increases with increasing concentration. The screening lengths for all electrolytes studied-including aqueous NaCl solutions, ionic liquids diluted with propylene carbonate, and pure ionic liquids-collapse onto a single curve when scaled by the dielectric constant. This nonmonotonic variation of the screening length with concentration, and its generality across ionic liquids and aqueous salt solutions, demonstrates an important characteristic of concentrated electrolytes of substantial relevance from biology to energy storage. PMID:27216986

  12. Country-specific birth weight and length in type 1 diabetes high-risk HLA genotypes in combination with prenatal characteristics

    OpenAIRE

    Sterner, Y; Törn, C; Lee, H-S.; Larsson, H; Winkler, C.; McLeod, W; K. Lynch; Simell, O; Ziegler, A; Schatz, D; Hagopian, W.; Rewers, M; She, J-X; Krischer, J P; Akolkar, B

    2011-01-01

    Objective: To examine the relationship between high-risk human leukocyte antigen (HLA) genotypes for type 1 diabetes and birth size in combination with prenatal characteristics in different countries. Study Design: Four high-risk HLA genotypes were enrolled in the Environmental determinants of Diabetes in the Young study newborn babies from the general population in Finland, Germany, Sweden and the United States. Stepwise regression analyses were used to adjust for country, parental physical ...

  13. Frequency and Path Length Scaling of Rain Attenuation from 38 GHz, 58 GHz and 93 GHz Data Obtained on Terrestrial Paths

    Czech Academy of Sciences Publication Activity Database

    Kvičera, V.; Grábner, M.; Fišer, Ondřej

    New York: IEEE, 2009, s. 2546-2550. ISBN 978-1-4244-4753-4. [European Conference on Antennas and Propagation /3./. Berlin (DE), 22.03.2009-27.03.2009] Grant ostatní: GA Mšk(CZ) OC 093 Institutional research plan: CEZ:AV0Z30420517 Keywords : rain attenuation * frequency scaling * path scaling * HAPs Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  14. Buoyancy Effects on the Scaling Characteristics of Atmospheric Boundary Layer Wind Fields in the Mesoscale Range

    CERN Document Server

    Kiliyanpilakkil, V P; Ruiz-Columbié, A; Araya, G; Castillo, L; Hirth, B; Burgett, W

    2015-01-01

    We have analyzed long-term wind speed time-series from five field sites up to a height of 300 m from the ground. Structure function-based scaling analysis has revealed that the scaling exponents in the mesoscale regime systematically depend on height. This anomalous behavior is shown to be caused by the buoyancy effects. In the framework of the extended self-similarity, the relative scaling exponents portray quasi-universal behavior.

  15. Scale-specific responses of saproxylic beetles to dead wood abundance and forest characteristics

    OpenAIRE

    Jacobsen, Rannveig

    2013-01-01

    Insects constitute a major part of global biodiversity. Saproxylic insects seem to be adversely affected by forest management due to the low volume of dead wood in traditionally managed forests. Studies of the relation between species richness of saproxylic insects and dead wood volume have been inconsistent with regard to spatial scale, and multiscale studies have found that this relation can differ depending on scale. Finding the right scale for dead wood surveys will allow for consistent r...

  16. Channel length scaling and the impact of metal gate work function on the performance of double gate-metal oxide semiconductor field-effect transistors

    Indian Academy of Sciences (India)

    D Rechem; S Latreche; C Gontrand

    2009-03-01

    In this paper, we study the effects of short channel on double gate MOSFETs. We evaluate the variation of the threshold voltage, the subthreshold slope, the leakage current and the drain-induced barrier lowering when channel length CH decreases. Further- more, quantum effects on the performance of DG-MOSFETs are addressed and discussed. We also study the influence of metal gate work function on the performance of nanoscale MOSFETs. We use a self-consistent Poisson–Schrödinger solver in two dimensions over the entire device. A good agreement with numerical simulation results is obtained.

  17. Scaling through pair-wise comparison method in required characteristics of students applying for post graduate programs

    Directory of Open Access Journals (Sweden)

    Nese Güler

    2009-04-01

    Full Text Available The Aim and Significance of the Research: The characteristics that lecturers wish students applying for post-graduate programs should possess are determined in this paper quantitatively through pairwise comparisons according to the lecturers’ responses. The fact that resources and studies concerning the issue of scaling are scarcely available has been the most significant driving force for researchers to conduct research on this issue. It is believed that this research will make contributions to the field of scaling, which has limited number of studies. Since this research is a work of scaling which is rarely seen in the field of education, it is thought that the research is significant.Method of Research: The research was conducted on the 129 lecturers working in the different departments of Hacettepe University in the fall and spring semesters in the 2006 – 2007 academic year. At the stage of preparing the tool of measurement, the 7 characteristics that were required students should possess for selection to post-graduate education programs were determined and a tool of measurement through which pairwise comparisons would be made were designed. Consequently, the scale value for each characteristic was marked on the line of numbers.Findings and Comments: According to the pairwise comparison, academic achievement score is in the first order. This is followed by the score gained in the interview, the purpose in entering the department, their level of English proficiency, ALES score, whether or not they are originally the students of the department and whether or not they have a letter of reference, respectively. According to results, when the students are selected to the post-graduate education programs it is suggested that the weighting of the students’ characteristics required is made by considering this order. In addition to this, it is thought that studying with different samples and different scaling methods provide important

  18. Scaling through pair-wise comparison method in required characteristics of students applying for post graduate programs

    Directory of Open Access Journals (Sweden)

    Nese Güler

    2009-04-01

    Full Text Available The Aim and Significance of the Research: The characteristics that lecturers wish students applying for post-graduate programs should possess are determined in this paper quantitatively through pairwise comparisons according to the lecturers' responses.  The fact that resources and studies concerning the issue of scaling are scarcely available has been the most significant driving force for researchers to conduct research on this issue. It is believed that this research will make contributions to the field of scaling, which has limited number of studies. Since this research is a work of scaling which is rarely seen in the field of education, it is thought that the research is significant. Method of Research: The research was conducted on the 129 lecturers working in the different departments of Hacettepe University in the fall and spring semesters in the 2006 - 2007 academic year. At the stage of preparing the tool of measurement, the 7 characteristics that were required students should possess for selection to post-graduate education programs were determined and a tool of measurement through which pairwise comparisons would be made were designed.  Consequently, the scale value for each characteristic was marked on the line of numbers. Findings and Comments: According to the pairwise comparison, academic achievement score is in the first order. This is followed by the score gained in the interview, the purpose in entering the department, their level of English proficiency, ALES score, whether or not they are originally the students of the department and whether or not they have a letter of reference, respectively. According to results, when the students are selected to the post-graduate education programs it is suggested that the weighting of the students' characteristics required is made by considering this order. In addition to this, it is thought that studying with different samples and different scaling methods provide important

  19. Career Adapt-Abilities Scale-Belgium Form: Psychometric Characteristics and Construct Validity

    Science.gov (United States)

    Dries, Nicky; Van Esbroeck, Raoul; van Vianen, Annelies E. M.; De Cooman, Rein; Pepermans, Roland

    2012-01-01

    The Dutch version of the Career Adapt-Abilities Scale-Belgium Form (CAAS-Belgium) consists of four scales, each with six items, which measure concern, control, curiosity, and confidence as psychosocial resources for managing occupational transitions, developmental tasks, and work traumas. A pilot survey was administered to 700 high school,…

  20. The Multi-Attitude Suicide Tendency Scale: Psychometric Characteristics in an American Sample.

    Science.gov (United States)

    Osman, Augustine; And Others

    1993-01-01

    Administered Multi-Attitude Suicide Tendency Scale (MAST) to 408 American college students. Like Israeli youth from other studies, suicide tendency in American sample was characterized by four attitudes: attraction to life, attraction to death, repulsion by life, and repulsion by death. All four factor scales showed good reliability estimates.…

  1. Electrical Characteristics, Electrode Sheath and Contamination Layer Behavior of a Meso-Scale Premixed Methane-Air Flame Under AC/DC Electric Fields

    Science.gov (United States)

    Chen, Qi; Yan, Limin; Zhang, Hao; Li, Guoxiu

    2016-05-01

    Electrical characteristics of a nozzle-attached meso-scale premixed methane-air flame under low-frequency AC (0-4300 V, 0-500 Hz) and DC (0-3300 V) electric fields were studied. I-V curves were measured under different experimental conditions to estimate the magnitude of the total current 100-102 μA, the electron density 1015-1016 m‑3 and further the power dissipation ≤ 0.7 W in the reaction zone. At the same time, the meso-scale premixed flame conductivity 10‑4-10‑3 Ω‑1·m‑1 as a function of voltage and frequency was experimentally obtained and was believed to represent a useful order-of magnitude estimate. Moreover, the influence of the collision sheath relating to Debye length (31–98 μm) and the contamination layer of an active electrode on measurements was discussed, based on the combination of simulation and theoretical analysis. As a result, the electrode sheath dimension was evaluated to less than 0.5 mm, which indicated a complex effect of the collision sheath on the current measurements. The surface contamination effect of an active electrode was further analyzed using the SEM imaging method, which showed elements immigration during the contamination layer formation process. supported by National Natural Science Foundation of China (No. 51376021), and the Fundamental Research Fund for Major Universities (No. 2013JBM079)

  2. Variation of the scaling characteristics of temporal and spatial distribution of earthquakes in Caucasus

    Science.gov (United States)

    Matcharashvili, T.; Chelidze, T.; Javakhishvili, Z.; Zhukova, N.

    2016-05-01

    In the present study we investigated the character of variation of long-range correlations features in earthquakes' temporal and spatial distribution in Caucasus. Scaling exponents of data sets of interearthquakes time intervals (waiting times) and interearthquakes distances were calculated by method of Detrended Fluctuation Analysis (DFA). Scaling exponent values were calculated for time windows with consecutive 500 data as well as for 5 year long sliding windows. It was shown that scaling exponents calculated for different windows vary in a wide range indicating variable behavior from antipersistent to persistent type. In the overwhelming majority of cases scaling exponents manifest persistent behavior both in the earthquakes time and spatial distributions. Close to 0.5 and antipersistent scaling exponents were obtained for the time periods when the strongest regional earthquakes occurred. We observed slow trend in long-range correlation features variation for the considered time period.

  3. The importance of different spatial scales in determining structural and functional characteristics of deep-sea infauna communities

    Directory of Open Access Journals (Sweden)

    J. Ingels

    2013-07-01

    Full Text Available The urge to understand spatial distributions of species and communities and their causative processes has continuously instigated the development and testing of conceptual models in spatial ecology. For the deep sea, there is evidence that structural and functional characteristics of benthic communities are regulated by a multitude of biotic and environmental processes that act in concert on different spatial scales, but the spatial patterns are poorly understood compared to those for terrestrial ecosystems. Deep-sea studies generally focus on very limited scale ranges, thereby impairing our understanding of which spatial scales and associated processes are most important in driving structural and functional diversity of communities. Here, we used an extensive integrated dataset of free-living nematodes from deep-sea sediments to unravel the importance of different spatial scales in determining benthic infauna communities. Multiple-factor multivariate permutational analyses were performed on different sets of community descriptors (structure, structural and functional diversity, standing stock. The different spatial scales investigated cover two margins in the northeast Atlantic, several submarine canyons/channel/slope areas, a bathymetrical range of 700–4300 m, different sampling locations at each station, and vertical sediment profiles. The results indicated that the most important spatial scale for structural and functional diversity and standing stock variability is the smallest one; infauna communities changed substantially more with differences between sediment depth layers than with differences associated to larger geographical or bathymetrical scales. Community structure differences were greatest between stations at both margins. Important regulating ecosystem processes and the scale on which they occur are discussed. The results imply that, if we are to improve our understanding of ecosystem patterns of deep-sea infauna and the

  4. FETAL FOOT LENGTH AND HAND LENGTH: RELATIONSHIP WITH CROWN RUMP LENGTH AND GESTATIONAL AGE

    Directory of Open Access Journals (Sweden)

    Garima

    2015-12-01

    Full Text Available BACKGROUND Estimation of gestational age of fetus is of great medicolegal importance. Multiple parameters of the fetal anatomical measurements are in use. However, gestational age assessment may be difficult in fetus with anencephaly, hydrocephalus, short limb dysplasia, post mortem destruction or in mutilated case. Study of literature suggests that fetal foot has a characteristic pattern of normal growth and the fetal foot shows gradual increase in length relative to the length of the embryo and could be used to estimate gestational age. The purpose of the present study is to determine the accuracy in estimating gestational age using fetal foot and hand length by studying its relation with crown rump length in the foetuses of Manipuri origin. AIMS AND OBJECTIVES 1 To study the relationship between fetal crown rump length and fetal hand and foot length, thereby determining the accuracy in estimating gestational age by a cross-sectional study. MATERIALS AND METHODS A total of 100 formalin fixed fetuses of Manipuri origin, obtained from the Department of Obstetrics and Gynaecology, Regional Institute of Medical Sciences, Imphal, were included in the study, carried out in the Department of Anatomy, from February 2015 to July 2015. The parameters studied were crown rump length, foot length and hand length of fetuses. The data was analysed using SPSS software by regression analysis. Graphs were also plotted to determine pattern of growth and their correlation with crown rump length if any. RESULTS A total of 100 fetuses were studied, of which 43 were females and 57 were males. The mean foot length and hand length progressively increased with increase in crown rump length. Measurements were not significantly different in right or left side or among male and female fetuses. A statistically significant linear relationship was seen between foot length and crown rump length of the fetus (r=0.980, p<0.0001 and hand length and crown rump length of the fetus

  5. Flow Scales of Influence on the Settling Velocities of Particles with Varying Characteristics.

    Science.gov (United States)

    Jacobs, Corrine N; Merchant, Wilmot; Jendrassak, Marek; Limpasuvan, Varavut; Gurka, Roi; Hackett, Erin E

    2016-01-01

    The settling velocities of natural, synthetic, and industrial particles were measured in a grid turbulence facility using optical measurement techniques. Particle image velocimetry and 2D particle tracking were used to measure the instantaneous velocities of the flow and the particles' trajectories simultaneously. We find that for particles examined in this study (Rep = 0.4-123), settling velocity is either enhanced or unchanged relative to stagnant flow for the range of investigated turbulence conditions. The smallest particles' normalized settling velocities exhibited the most consistent trends when plotted versus the Kolmogorov-based Stokes numbers suggesting that the dissipative scales influence their dynamics. In contrast, the mid-sized particles were better characterized with a Stokes number based on the integral time scale. The largest particles were largely unaffected by the flow conditions. Using proper orthogonal decomposition (POD), the flow pattern scales are compared to particle trajectory curvature to complement results obtained through dimensional analysis using Stokes numbers. The smallest particles are found to have trajectories with curvatures of similar scale as the small flow scales (higher POD modes) whilst mid-sized particle trajectories had curvatures that were similar to the larger flow patterns (lower POD modes). The curvature trajectories of the largest particles did not correspond to any particular flow pattern scale suggesting that their trajectories were more random. These results provide experimental evidence of the "fast tracking" theory of settling velocity enhancement in turbulence and demonstrate that particles align themselves with flow scales in proportion to their size. PMID:27513958

  6. Two-phase flow characteristics during flow boiling of halocarbon refrigerants in micro-scale channels

    International Nuclear Information System (INIS)

    Quasi-diabatic two-flow pattern visualizations and measurements of elongated bubble velocity, frequency and length were performed. The tests were run for R134a evaporating in a stainless steel tube with diameter of 2.32 mm, mass velocities from 50 to 600 kg/m2s and saturation temperatures of 22 deg C, 31 deg C and 41 deg C. The tube was heated by applying a direct DC current to its surface. Images from a high-speed video-camera (8000 frames/s) obtained through a transparent tube just downstream of the heated section were used to identify the following flow patterns: bubbly, elongated bubbles, churn and annular. Dryout conditions were also characterized. Local heat transfer results were considered when investigating the presence of stratified flows. The visualized flow patterns were compared against the predictions provided by Barnea et al., Felcar et al. and Revellin and Thome. For the present database, the method recently proposed by Felcar et al. provides the best predictions. Additionally, elongated bubble velocities, frequencies and lengths were determined based on an analysis of high speed videos. Results suggested that the elongated bubble velocity depends on mass velocity, vapor quality and saturation temperature, and is independent of bubble length. The bubble velocity increases with increasing mass velocity and vapor quality and decreases with increasing saturation temperature. Additionally, bubble velocity was correlated as a linear function of the two-phase superficial velocity. (author)

  7. A study on the seismic response characteristics of soil-structure system at Hualien Large Scale Seismic Test (LSST)

    International Nuclear Information System (INIS)

    This paper presents analysis results of earthquake response data recorded from the Hualien Large-Scale Seismic Test (LSST). A Soil-Structure Interaction (SSI) experiment was conducted in a seismically active region in Hualien. To obtain earthquake data for quantifying SSI effects and to improve SSI analysis method, a 1/4-th scale of a typical nuclear reactor cylindrical concrete containment was constructed in the site where both the containment model and its surrounding soil, surface and sub-surface, are extensively instrumented to record earthquake data. In between September 1993 and March 2002 more than seventy earthquakes with Richter magnitudes ranging from 2.6 to 7.3 have been recorded at the site. The recorded data were analyzed to provide information on the response characteristics of the Hualien soil-structure system, the SSI effects and the ground motion characteristics

  8. Generation and analysis of a large-scale expressed sequence tags from a full-length enriched cDNA library of Siberian tiger (Panthera tigris altaica).

    Science.gov (United States)

    Guo, Yu; Liu, Changqing; Lu, Taofeng; Liu, Dan; Bai, Chunyu; Li, Xiangchen; Ma, Yuehui; Guan, Weijun

    2014-05-15

    In this study, a full-length enriched cDNA library was successfully constructed from Siberian tiger, the world's most endangered species. The titers of primary and amplified libraries were 1.28×10(6)pfu/mL and 1.59×10(10)pfu/mL respectively. The proportion of recombinants from unamplified library was 91.3% and the average length of exogenous inserts was 1.06kb. A total of 279 individual ESTs with sizes ranging from 316 to 1258bps were then analyzed. Furthermore, 204 unigenes were successfully annotated and involved in 49 functions of the GO classification, cell (175, 85.5%), cellular process (165, 80.9%), and binding (152, 74.5%) are the dominant terms. 198 unigenes were assigned to 156 KEGG pathways, and the pathways with the most representation are metabolic pathways (18, 9.1%). The proportion pattern of each COG subcategory was similar among Panthera tigris altaica, P. tigris tigris and Homo sapiens, and general function prediction only cluster (44, 15.8%) represents the largest group, followed by translation, ribosomal structure and biogenesis (33, 11.8%), replication, recombination and repair (24, 8.6%), and only 7.2% ESTs classified as novel genes. Moreover, the recombinant plasmid pET32a-TAT-COL6A2 was constructed, coded for the Trx-TAT-COL6A2 fusion protein with two 6× His-tags in N and C-terminal. After BCA assay, the concentration of soluble Trx-TAT-COL6A2 recombinant protein was 2.64±0.18mg/mL. This library will provide a useful platform for the functional genome and transcriptome research of for the P. tigris and other felid animals in the future. PMID:24630959

  9. Perceptions of Natural Social Landscape Characteristics Between Cities and Across Scales

    Science.gov (United States)

    As the global population becomes increasingly urban, there is greater attention toward human-natural resources interactions in urban areas. Multiple disciplines have explored synergies and dynamics between community characteristics and individual preferences that vary across sca...

  10. Comparison of theoretical predicted longitudinal aerodynamic characteristics with full-scale wind tunnel data on the ATLIT airplane

    Science.gov (United States)

    Vandam, C. P. G.; Griswold, M.; Roskam, J.

    1979-01-01

    An analytical method is presented for predicting the lift coefficient, the pitching moment coefficient, and the drag coefficient of light, twin-engine, propeller-driven airplanes. The method was applied to the Advanced Technology Light Twin-Engine airplane. The calculated characteristics were then correlated against full scale wind tunnel data. The analytical method was found to predict the drag and pitching moment fairly well. However, the lift prediction was extremely poor.

  11. Aerosol characteristics in the offgas from a pilot-scale sluicing operation

    International Nuclear Information System (INIS)

    A pilot-scale study was performed to simulate conditions anticipated during sluicing operations to retrieve waste in single-shell Tank 241-C-106 at the US Department of Energy's Hanford Site in southeastern Washington. The objective of the study was to identify and characterize the potential aerosol source term at the inlet of the headspace exhaust ventilation system during sluicing operations. The information is needed to support decisions for components to be used in the full-scale operation. A secondary objective was to qualitatively evaluate the visibility during sluicing. Three simulated sluicing tests were performed in the 336 Building's quarter-scale waste tank facility located at Hanford. Scaling relationships were used to guide modifications to the quarter-scale tank to accommodate tests that simulated tank geometry, sluicing, and ventilation conditions in the full-scale tank. Simulated sluicing fluids were targeted on solid and liquid surfaces during the tests. Test conditions were monitored, and aerosol measurements were made in the offgas ventilation duct. Also during the tests, an in-tank camera was used to monitor visibility

  12. Numerical modeling of fast electron transport in short pulse laser-solid interactions with long scale-length pre-formed plasma

    International Nuclear Information System (INIS)

    Results of numerical modeling of the experiment carried out to investigate the effect of long scale pre-plasma on fast electron transport are presented. A peculiar ring-like structure in Cu Kα x-ray emission was seen experimentally when a short pulse laser (intensity ∼3 x 1018 W cm-2) interacted with a long scale pre-plasma. The long scale pre-plasma, produced by irradiation of a long pulse laser on a flat target having copper fluorescence layer sandwiched between aluminum layers, is modeled with the radiation hydrodynamic code, h2d. Fast electron transport modeling performed with the hybrid particle-in-cell code, LSP, suggests that the ring structure is due to the refluxing of low energy (∼50 keV) fast electrons traveling in the pre-formed plasma back to the solid target. Modeling shows that the excitation of strong electrostatic fields near the transverse plasma boundary is responsible for this refluxing. Details of the modeling along with the exact mechanism of formation of ring-like Kα x-ray emission are discussed.

  13. [Multiple time scales analysis of spatial differentiation characteristics of non-point source nitrogen loss within watershed].

    Science.gov (United States)

    Liu, Mei-bing; Chen, Xing-wei; Chen, Ying

    2015-07-01

    Identification of the critical source areas of non-point source pollution is an important means to control the non-point source pollution within the watershed. In order to further reveal the impact of multiple time scales on the spatial differentiation characteristics of non-point source nitrogen loss, a SWAT model of Shanmei Reservoir watershed was developed. Based on the simulation of total nitrogen (TN) loss intensity of all 38 subbasins, spatial distribution characteristics of nitrogen loss and critical source areas were analyzed at three time scales of yearly average, monthly average and rainstorms flood process, respectively. Furthermore, multiple linear correlation analysis was conducted to analyze the contribution of natural environment and anthropogenic disturbance on nitrogen loss. The results showed that there were significant spatial differences of TN loss in Shanmei Reservoir watershed at different time scales, and the spatial differentiation degree of nitrogen loss was in the order of monthly average > yearly average > rainstorms flood process. TN loss load mainly came from upland Taoxi subbasin, which was identified as the critical source area. At different time scales, land use types (such as farmland and forest) were always the dominant factor affecting the spatial distribution of nitrogen loss, while the effect of precipitation and runoff on the nitrogen loss was only taken in no fertilization month and several processes of storm flood at no fertilization date. This was mainly due to the significant spatial variation of land use and fertilization, as well as the low spatial variability of precipitation and runoff. PMID:26710649

  14. Generation and analysis of large-scale expressed sequence tags (ESTs from a full-length enriched cDNA library of porcine backfat tissue

    Directory of Open Access Journals (Sweden)

    Lee Hae-Young

    2006-02-01

    Full Text Available Abstract Background Genome research in farm animals will expand our basic knowledge of the genetic control of complex traits, and the results will be applied in the livestock industry to improve meat quality and productivity, as well as to reduce the incidence of disease. A combination of quantitative trait locus mapping and microarray analysis is a useful approach to reduce the overall effort needed to identify genes associated with quantitative traits of interest. Results We constructed a full-length enriched cDNA library from porcine backfat tissue. The estimated average size of the cDNA inserts was 1.7 kb, and the cDNA fullness ratio was 70%. In total, we deposited 16,110 high-quality sequences in the dbEST division of GenBank (accession numbers: DT319652-DT335761. For all the expressed sequence tags (ESTs, approximately 10.9 Mb of porcine sequence were generated with an average length of 674 bp per EST (range: 200–952 bp. Clustering and assembly of these ESTs resulted in a total of 5,008 unique sequences with 1,776 contigs (35.46% and 3,232 singleton (65.54% ESTs. From a total of 5,008 unique sequences, 3,154 (62.98% were similar to other sequences, and 1,854 (37.02% were identified as having no hit or low identity (Sus scrofa. Gene ontology (GO annotation of unique sequences showed that approximately 31.7, 32.3, and 30.8% were assigned molecular function, biological process, and cellular component GO terms, respectively. A total of 1,854 putative novel transcripts resulted after comparison and filtering with the TIGR SsGI; these included a large percentage of singletons (80.64% and a small proportion of contigs (13.36%. Conclusion The sequence data generated in this study will provide valuable information for studying expression profiles using EST-based microarrays and assist in the condensation of current pig TCs into clusters representing longer stretches of cDNA sequences. The isolation of genes expressed in backfat tissue is the

  15. Voice characteristics of patients with glottic carcinoma analyzed using 'RBH' and 'GIRBAS' scales

    Directory of Open Access Journals (Sweden)

    Mitrović Slobodan

    2003-01-01

    Full Text Available Introduction Subjective voice analysis represents a diagnostic tool in phoniatry and is a part of everyday practice if a phoniatrist has a 'trained ear'. Material and methods This clinical prospective study included a sample of 20 male patients with malignant tumors involving one vocal cord - right or left. All patients underwent otorhinolaryngological and phoniatric examinations. Subjective acoustic analysis was done when patients pronounced numbers from 1 to 10. Afterwards, voice quality was evaluated separately by two professionals using a 4-levels scale: RBH scale (roughness-breathiness-hoarseness and GIRBAS scale (grade-instability-roughness-breathiness-asthenia-strain. Results 60% of patients presented with vocal cord immobility. Subjective acoustic analysis revealed hoarseness in 100% of patients (the most frequent value was Mod=3 intense hoarseness in 45% patients. Instability existed in 100% of patient (40% moderate, 40% intense. Strained voice existed in 100%, most frequently intense (45%. Conclusions All patients with glottic carcinoma presented with hoarseness, strain and instability of phonation. Non vibration of vocal cord significantly affects the degree of dysphonia, roughness, strain and instability. Aerodynamic changes affect voice hoarseness. RBH scale is simple, but GIRBAS scale described more psyhoacoustic phenomena most important in patients with glottic carcinoma.

  16. A two-dimensional analysis of the sensitivity of a pulse first break to wave speed contrast on a scale below the resolution length of ray tomography.

    Science.gov (United States)

    Willey, Carson L; Simonetti, Francesco

    2016-06-01

    Mapping the speed of mechanical waves traveling inside a medium is a topic of great interest across many fields from geoscience to medical diagnostics. Much work has been done to characterize the fidelity with which the geometrical features of the medium can be reconstructed and multiple resolution criteria have been proposed depending on the wave-matter interaction model used to decode the wave speed map from scattering measurements. However, these criteria do not define the accuracy with which the wave speed values can be reconstructed. Using two-dimensional simulations, it is shown that the first-arrival traveltime predicted by ray theory can be an accurate representation of the arrival of a pulse first break even in the presence of diffraction and other phenomena that are not accounted for by ray theory. As a result, ray-based tomographic inversions can yield accurate wave speed estimations also when the size of a sound speed anomaly is smaller than the resolution length of the inversion method provided that traveltimes are estimated from the signal first break. This increased sensitivity however renders the inversion more susceptible to noise since the amplitude of the signal around the first break is typically low especially when three-dimensional anomalies are considered. PMID:27369139

  17. Estimation of genome length

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The genome length is a fundamental feature of a species. This note outlined the general concept and estimation method of the physical and genetic length. Some formulae for estimating the genetic length were derived in detail. As examples, the genome genetic length of Pinus pinaster Ait. and the genetic length of chromosome Ⅵ of Oryza sativa L. were estimated from partial linkage data.

  18. Emotional Eating Scale for Children and Adolescents: Psychometric Characteristics in a Spanish Sample

    Science.gov (United States)

    Perpina, Conxa; Cebolla, Ausias; Botella, Cristina; Lurbe, Empar; Torro, Maria-Isabel

    2011-01-01

    The aims of this study were to validate the Emotional Eating Scale version for children (EES-C) in a Spanish population and study the differences in emotional eating among children with binge eating (BE), overeating (OE), and no episodes of disordered eating (NED). The questionnaire was completed by 199 children aged 9 to 16 years. Confirmatory…

  19. Psychometric Characteristics of the Social Justice Scale's Turkish Form and a Structural Equation Modeling

    Science.gov (United States)

    Cirik, Ilker

    2015-01-01

    Problem Statement: In order to provide equal educational opportunities for students, teachers should encourage their students to have an effective voice concerning social justice. Studies reveal that teachers face trouble when transferring from the concept of social justice as theory to social justice as practice. A scale which will be developed…

  20. Multiple Time-scale Characteristics of Runoff Variations in Middle Reaches of Huolin River and Their Effects

    Institute of Scientific and Technical Information of China (English)

    LU Xiaoning; DENG Wei; ZHANG Shuqing

    2007-01-01

    The Huolin River is one of the most important water sources for Xianghai wetland, Horqin wetland, and Chaganhu wetland in the western Songnen Plain of Northeast China. The annual runoff series of 46 years at Baiyunhushuo Hydrologic Station, which is located in the middle reaches of the Huolin River, were analyzed by using wavelet analysis. Main objective was to discuss the periodic characteristics of the runoff, and examine the temporal patterns of the Huolin River recharging to the floodplain wetlands in the lower reaches of the river, and the corresponding effects of recharging variation on the environmental evolution of the wetlands. The results show that the annual runoff varied mainly at three time scales. The intensities of periodical signals at different time scales were strongly characterized by local distribution in its time frequency domain. The interdecadal variation at a scale of more than 30yr played a leading role in the temporal pattern of runoff variation, and at this scale, the runoff at Baiyunhushuo Hydrologic Station varied in turn of flood, draught and flood. Accordingly, the landscape of the floodplain wetlands presented periodic features, especially prominent before the 1990s. Compared with intense human activities, the runoff periodic pattern at middle (10-20yr) and small (l-10yr) scales, which has relatively low energy, exerted unobvious effects on the environmental evolution of the floodplain wetlands, especially after the 1990s.

  1. Impact of climate change on flood characteristics in Brahmaputra basin using a macro-scale distributed hydrological model

    Indian Academy of Sciences (India)

    Shyamal Ghosh; Subashisa Dutta

    2012-06-01

    Being the highest specific discharge river system in the world, the Brahmaputra river experiences a number of long-duration flood waves during the monsoon season annually. In order to assess the flood characteristics at the basin and tributary scales, a physically based macro-scale distributed hydrological model (DHM) has been calibrated and validated for 9 wet years. The model performance has been evaluated in terms of prediction of the flood characteristics such as peak discharge, flood duration, arrival time of flood wave, timing of the peak flow and number of flood waves per season. Future changes in the flood wave characteristics of the basin have been evaluated using the validated model with bias-corrected future-projected meteorological scenario from a regional climate model (RCM). Likelihood analysis of the simulated flow time series reveals that significant increase in both peak discharge and flood duration is expected for both the pre-monsoonal and monsoonal seasons in the basin, but the number of flood waves per season would be reduced. Under the projected climate change scenario, it is expected that there will be more catastrophic floods in the basin.

  2. Time and frequency domain characteristics of detrending-operation-based scaling analysis: Exact DFA and DMA frequency responses

    Science.gov (United States)

    Kiyono, Ken; Tsujimoto, Yutaka

    2016-07-01

    We develop a general framework to study the time and frequency domain characteristics of detrending-operation-based scaling analysis methods, such as detrended fluctuation analysis (DFA) and detrending moving average (DMA) analysis. In this framework, using either the time or frequency domain approach, the frequency responses of detrending operations are calculated analytically. Although the frequency domain approach based on conventional linear analysis techniques is only applicable to linear detrending operations, the time domain approach presented here is applicable to both linear and nonlinear detrending operations. Furthermore, using the relationship between the time and frequency domain representations of the frequency responses, the frequency domain characteristics of nonlinear detrending operations can be obtained. Based on the calculated frequency responses, it is possible to establish a direct connection between the root-mean-square deviation of the detrending-operation-based scaling analysis and the power spectrum for linear stochastic processes. Here, by applying our methods to DFA and DMA, including higher-order cases, exact frequency responses are calculated. In addition, we analytically investigate the cutoff frequencies of DFA and DMA detrending operations and show that these frequencies are not optimally adjusted to coincide with the corresponding time scale.

  3. Effects of DEM scale on the spatial distribution of the TOPMODEL topographic wetness index and its correlations to watershed characteristics

    Science.gov (United States)

    Drover, D. R.; Jackson, C. R.; Bitew, M.; Du, E.

    2015-11-01

    Topographic wetness indices (TWIs) calculated from digital elevation models (DEMs) are meant to predict relative landscape wetness and should have predictive power for soil and vegetation attributes. While previous researchers have shown cumulative TWI distributions shift to larger values as DEM resolution decreases, there has been little work assessing how DEM scales affect TWI spatial distributions and correlations with soil and vegetation properties. We explored how various DEM resolutions (2, 5, 10, 20, 30, and 50 m) subsampled from high definition LiDAR altered the spatial distribution of TWI values and the correlations of these values with soil characteristics determined from point samples, Natural Resources Conservation Service (NRCS) soil units, depths to groundwater, and managed vegetation distributions within a first order basin in the Upper Southeastern Coastal Plain with moderate slopes, flat valleys, and several wetlands. Point-scale soil characteristics were determined by laboratory analysis of point samples collected from riparian transects and hillslope grids. DEM scale affected the spatial distribution of TWI values in ways that affect our interpretation of landscape processes. At the finest DEM resolutions, valleys disappeared as TWI values were driven by local microtopography and not basin position. Spatial distribution of TWI values most closely matched the spatial distribution of soils, depth to groundwater, and vegetation stands for the 10, 20, and 30 m resolutions. DEM resolution affected the shape and direction of relationships between soil nitrogen and carbon contents and TWI values, but TWI values provided poor prediction of soil chemistry at all resolutions.

  4. Effects of DEM scale on the spatial distribution of the TOPMODEL topographic wetness index and its correlations to watershed characteristics

    Directory of Open Access Journals (Sweden)

    D. R. Drover

    2015-11-01

    Full Text Available Topographic wetness indices (TWIs calculated from digital elevation models (DEMs are meant to predict relative landscape wetness and should have predictive power for soil and vegetation attributes. While previous researchers have shown cumulative TWI distributions shift to larger values as DEM resolution decreases, there has been little work assessing how DEM scales affect TWI spatial distributions and correlations with soil and vegetation properties. We explored how various DEM resolutions (2, 5, 10, 20, 30, and 50 m subsampled from high definition LiDAR altered the spatial distribution of TWI values and the correlations of these values with soil characteristics determined from point samples, Natural Resources Conservation Service (NRCS soil units, depths to groundwater, and managed vegetation distributions within a first order basin in the Upper Southeastern Coastal Plain with moderate slopes, flat valleys, and several wetlands. Point-scale soil characteristics were determined by laboratory analysis of point samples collected from riparian transects and hillslope grids. DEM scale affected the spatial distribution of TWI values in ways that affect our interpretation of landscape processes. At the finest DEM resolutions, valleys disappeared as TWI values were driven by local microtopography and not basin position. Spatial distribution of TWI values most closely matched the spatial distribution of soils, depth to groundwater, and vegetation stands for the 10, 20, and 30 m resolutions. DEM resolution affected the shape and direction of relationships between soil nitrogen and carbon contents and TWI values, but TWI values provided poor prediction of soil chemistry at all resolutions.

  5. Length of a Hanging Cable

    Directory of Open Access Journals (Sweden)

    Eric Costello

    2011-01-01

    Full Text Available The shape of a cable hanging under its own weight and uniform horizontal tension between two power poles is a catenary. The catenary is a curve which has an equation defined by a hyperbolic cosine function and a scaling factor. The scaling factor for power cables hanging under their own weight is equal to the horizontal tension on the cable divided by the weight of the cable. Both of these values are unknown for this problem. Newton's method was used to approximate the scaling factor and the arc length function to determine the length of the cable. A script was written using the Python programming language in order to quickly perform several iterations of Newton's method to get a good approximation for the scaling factor.

  6. Diet Activity Characteristic of Large-scale Sports Events Based on HACCP Management Model

    OpenAIRE

    Xiao-Feng Su; Li Guo; Li-Hua Gao; Chang-Zhuan Shao

    2015-01-01

    The study proposed major sports events dietary management based on "HACCP" management model. According to the characteristic of major sports events catering activities. Major sports events are not just showcase level of competitive sports activities which have become comprehensive special events including social, political, economic, cultural and other factors, complex. Sporting events conferred reach more diverse goals and objectives of economic, political, cultural, technological and other ...

  7. Diet Activity Characteristic of Large-scale Sports Events Based on HACCP Management Model

    Directory of Open Access Journals (Sweden)

    Xiao-Feng Su

    2015-01-01

    Full Text Available The study proposed major sports events dietary management based on "HACCP" management model. According to the characteristic of major sports events catering activities. Major sports events are not just showcase level of competitive sports activities which have become comprehensive special events including social, political, economic, cultural and other factors, complex. Sporting events conferred reach more diverse goals and objectives of economic, political, cultural, technological and other influence and impact.

  8. Three-Dimensional Simulation of SOFC Anode Polarization Characteristics Based on Sub-Grid Scale Model

    OpenAIRE

    Kishimoto, Masashi; Iwai, Hiroshi; Saito, Motohiro; Yoshida, Hideo

    2011-01-01

    Three-dimensional numerical simulation of SOFC anode polarization is conducted with a structure obtained by a focused ion beam and scanning electron microscope (FIB-SEM). Electronic, ionic and gaseous transports with electrochemical reaction are considered. A sub-grid scale model is newly developed and effectively used to evaluate the transport flux in the porous structure. The proposed SGS model shows its potential to reasonably evaluate the transport flux considering the microstructure smal...

  9. Thermal characteristics of various biomass fuels in a small-scale biomass combustor

    International Nuclear Information System (INIS)

    Biomass combustion is a mature and reliable technology, which has been used for heating and cooking. In the UK, biomass currently qualifies for financial incentives such as the Renewable Heat Incentive (RHI). Therefore, it is vital to select the right type of fuel for a small-scale combustor to address different types of heat energy needs. In this paper, the authors attempt to investigate the performance of a small-scale biomass combustor for heating, and the impact of burning different biomass fuels on useful output energy from the combustor. The test results of moisture content, calorific value and combustion products of various biomass samples were presented. Results from this study are in general agreement with published data as far as the calorific values and moisture contents are concerned. Six commonly available biomass fuels were tested in a small-scale combustion system, and the factors that affect the performance of the system were analysed. In addition, the study has extended to examine the magnitude and proportion of useful heat, dissipated by convection and radiation while burning different biomass fuels in the small-scale combustor. It is concluded that some crucial factors have to be carefully considered before selecting biomass fuels for any particular heating application. - Highlights: • Six biomass materials combustion performance in a small combustor was examined. • Fuel combustion rate and amount of heat release has varied between materials. • Heat release by radiation, convection and flue gasses varied between materials. • Study helps engineers and users of biomass systems to select right materials

  10. Characteristics of Turbulence-driven Plasma Flow and Origin of Experimental Empirical Scalings of Intrinsic Rotation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W. X.; Hahm, T. S.; Ethier, S.; Rewoldt, G.; Tang, W. M.; Lee, W. W.; Diamond, P. H.

    2011-03-20

    Toroidal plasma flow driven by turbulent torque associated with nonlinear residual stress generation is shown to recover the observed key features of intrinsic rotation in experiments. Specifically, the turbulence-driven intrinsic rotation scales close to linearly with plasma gradients and the inverse of the plasma current, qualitatively reproducing empirical scalings obtained from a large experimental data base. The effect of magnetic shear on the symmetry breaking in the parallel wavenumber spectrum is identified. The origin of the current scaling is found to be the enhanced kll symmetry breaking induced by increased radial variation of the safety factor as the current decreases. The physics origin for the linear dependence of intrinsic rotation on the pressure gradient comes from the fact that both turbulence intensity and the zonal flow shear, which are two key ingredients for driving the residual stress, are increased with the strength of the turbulence drives, which are R/LTe and R/Lne for the collisionless trapped electron mode (CTEM). Highlighted results also include robust radial pinches in toroidal flow, heat and particle transport driven by CTEM turbulence, which emerge "in phase", and are shown to play important roles in determining plasma profiles. Also discussed are experimental tests proposed to validate findings from these gyrokinetic simulations.

  11. Cyclic Codes of Length 2

    Indian Academy of Sciences (India)

    Manju Pruthi

    2001-11-01

    In this paper explicit expressions of + 1 idempotents in the ring $R = F_q[X]/\\langle X^{2^m}-1\\rangle$ are given. Cyclic codes of length 2 over the finite field , of odd characteristic, are defined in terms of their generator polynomials. The exact minimum distance and the dimension of the codes are obtained.

  12. Information, polarization and term length in democracy

    DEFF Research Database (Denmark)

    Schultz, Christian

    2008-01-01

    This paper considers term lengths in a representative democracy where the political issue divides the population on the left-right scale. Parties are ideologically different and better informed about the consequences of policies than voters are. A short term length makes the government more accou...... the uncertainty is large and parties are not very polarized. Partisan voters always prefer a long term length. When politicians learn while in office a long term length becomes more attractive for swing voters....

  13. Definition of Magnetic Exchange Length

    Energy Technology Data Exchange (ETDEWEB)

    Abo, GS; Hong, YK; Park, J; Lee, J; Lee, W; Choi, BC

    2013-08-01

    The magnetostatic exchange length is an important parameter in magnetics as it measures the relative strength of exchange and self-magnetostatic energies. Its use can be found in areas of magnetics including micromagnetics, soft and hard magnetic materials, and information storage. The exchange length is of primary importance because it governs the width of the transition between magnetic domains. Unfortunately, there is some confusion in the literature between the magnetostatic exchange length and a similar distance concerning magnetization reversal mechanisms in particles known as the characteristic length. This confusion is aggravated by the common usage of two different systems of units, SI and cgs. This paper attempts to clarify the situation and recommends equations in both systems of units.

  14. The de novo formation of a vascular network, in warm-blooded embryos, occurs via a self-assembly process that spans multiple length and time scales

    Science.gov (United States)

    Little, Charles D.

    2007-03-01

    Taking advantage of wide-field, time-lapse microscopy we examined the assembly of vascular polygonal networks in whole bird embryos and in explanted embryonic mouse tissue (allantois). Primary vasculogenesis assembly steps range from cellular (1-10 μm) to tissue (100μm-1mm) level events: Individual vascular endothelial cells extend protrusions and move with respect to the extracellular matrix/surrounding tissue. Consequently, long-range, tissue-level, deformations directly influence the vascular pattern. Experimental perturbation of endothelial-specific cell-cell adhesions (VE-cadherin), during mouse vasculogenesis, permitted dissection of the cellular motion required for sprout formation. In particular, cells are shown to move actively onto vascular cords that are subject to strain via tissue deformations. Based on the empirical data we propose a simple model of preferential migration along stretched cells. Numerical simulations reveal that the model evolves into a quasi-stationary pattern containing linear segments, which interconnect above a critical volume fraction. In the quasi-stationary state the generation of new branches offsets the coarsening driven by surface tension. In agreement with empirical data, the characteristic size of the resulting polygonal pattern is density-independent within a wide range of volume fractions. These data underscore the potential of combining physical studies with experimental embryology as a means of studying complex morphogenetic systems. In collaboration with Brenda J. Rongish^1, Andr'as Czir'ok^1,2, Erica D. Perryn^1, Cheng Cui^1, and Evan A. Zamir^1 ^1Department of Anatomy and Cell Biology, the University of Kansas Medical Center, Kansas City, KS ^2Department of Biological Physics, E"otv"os Lor'and University, Budapest, Hungary.

  15. Effects of Fuselage Modifications on the Drag Characteristics of a 1/20-Scale Model of the Convair F-102 Airplane at Transonic Speeds

    Science.gov (United States)

    Kelly, Thomas C.; Osborne, Robert S.

    1954-01-01

    An investigation has been conducted in the Langley 8-foot transonic tunnel to determine the effects of several fuselage modifications on the transonic drag-rise characteristics of a 1/20-scale model of the Convair F-102 airplane. Tests covered an angle-of-attack range from 0deg to about 10deg and a Mach number range from 0.60 to 1.14. Results indicated that the transonic drag rise .for the basic F-102 airplane could be substantially reduced by extending the fuselage after-body approximately 8 percent of the fuselage length. Tests of other bodies indicated that a shorter (4-percent) afterbody extension may have a similar effect on the drag rise. Further improvement of the axial cross-sectional-area distribution of the 8-percent extended configuration through the addition of fuselage volume resulted in additional reductions in the drag rise at a Mach number of 1.0 and caused no or only slight drag penalties at the higher Mach numbers. The results of the present tests generally substantiate the area-rule concept with respect to the prediction of the transonic drag rise through the use of an equivalent-area body of revolution for a practical delta-wing airplane configuration.

  16. Meat Quality Characteristics of Small East African Goats and Norwegian Crosses Finished under Small Scale Farming Conditions

    OpenAIRE

    Hozza, W. A.; Mtenga, L. A.; Kifaro, G. C.; Shija, D. S. N.; Mushi, D. E.; Safari, J. G.; Shirima, E. J. M.

    2014-01-01

    The aim of the experiment was to study the effect of feeding system on meat quality characteristics of Small East African (SEA) goats and their crosses with Norwegian (SEA×N) goats finished under small scale farming conditions. Twenty four castrated goats at the age of 18 months with live body weight of 16.7±0.54 kg from each breed (SEA and SEA×N) were distributed in a completely randomized design in a 2×3 factorial arrangement (two breed, and three dietary treatments). The dietary treatments...

  17. Ground State Depleted (GSD) Solid State Lasers: Principles, Characteristics, And Scaling

    Science.gov (United States)

    Krupke, William F.; Chase, Lloyd L.

    1989-07-01

    A novel class of rare earth doped solid state lasers is described. The Ground State Depleted (GSD) laser is pumped by an intense (>tens kW/cm2) narrowband (75%), (3) a gain element that is optically thick at the pump wavelength, (4) a gain element that has a substantially uniform gain distribution due to a bleaching of the pump transition at the pump intensity utilized. These features enable efficient room temperature operation of rare earth ion laser transitions terminating on the ground manifold. The relationships between laser parameters (cross sections, saturation fluences and fluxes, bleaching wave velocities, etc.) are given and laser performance scaling relationships are presented and discussed.

  18. Twin Reversed Arterial Perfusion (TRAP Sequence; Characteristic Gray-Scale and Doppler Ultrasonography Findings

    Directory of Open Access Journals (Sweden)

    Buyukkaya

    2015-07-01

    Full Text Available Twin reversed arterial perfusion (TRAP sequence is a syndrome with poor prognosis, seen only in monochorionic monozygotic twin pregnancies. The incidence is one in 35.000 births and one in 100 monozygotic twin pregnancies. It is characterized with a recipient fetus exhibiting lethal anomalies including acardia and a pump fetus. Mortality is usually due to heart failure or premature labor caused by polyhydramnios of pump fetus. Herein, we report a case of TRAP sequence that emphasizes the importance of gray-scale and color Doppler imaging in the diagnosis and management of TRAP sequence.

  19. Optimization Design of Medium-length Hole Blasting in Small-scale and Opencast Quarry%小型露天采石场中深孔爆破方案优化设计

    Institute of Scientific and Technical Information of China (English)

    陈星明; 肖正学; 谭诚; 尹轶东

    2012-01-01

    Achieve higher efficiency is a aim of mining enterprises on the basis of safety produce, choice of the blasting method is an important restraining factor about mining costs. The deficiencies of medium-length hole blasting in small-scale and opencast quarry of Mianyang area were analyzed and pointed out by detailed survey. The suitable method of medium-length hole blasting in small-scale and opencast quarry of Mianyang area were designed according to deposit condition of mine and production status. It achieved good results on safe production and economic efficiency by carrying out the design. The optimization design can promote and improve small Small-scale and opencast quarry safety in production and economy efficiency.%钻孔爆破方式的选择是采矿成本高低的一个重要制约因素:通过调研绵阳地区部分小型露天采石场使用的中深孔爆破的方案,分析并指出其在爆破质量、生产安全性能和效率方面存在的不足之处,根据矿体赋存条件和实际生产状况对该中深孔爆破方案进行了重新设计,并进行了矿山现场实践,在安全生产和经济效果方面取得了良好的效果.研究成果可用于小型采石场.

  20. Spectral Characteristics of Large-Scale Radio Emission Areas in Coronal Holes

    CERN Document Server

    Prosovetsky, D V; Kochanov, A A

    2013-01-01

    The spectra of the coronal hole radio emission in solar cycles 23 and 24 have been studied based on RATAN-600 data in the 4-16.5 GHz range at frequencies of 5.7 and 17 GHz and 327 MHz. It has been found that bright features of coronal hole microwave emission at 17 GHz and dark features at 5.7 GHz can exist in coronal holes when the spectral index is 1.25-1.5 in the 6.5-16.5 GHz range; the radio spectrum in this range is flat when coronal holes are indiscernible against the background of a quiet Sun. The possible vertical scale of the solar atmosphere over coronal holes is discussed.

  1. Torque Characteristics Simulation on Small Scale Combined Type Vertical Axis Wind Turbine

    Science.gov (United States)

    Feng, Fang; Li, Shengmao; Li, Yan; Xu, Dan

    The straight-bladed vertical axis wind turbine (SB-VAWT) receives more attentions recently for its goodness of simple design, low cost and good maintenance. However, its starting performance is poor. To increase its starting torque, Savonius rotor was combined on the SB-VAWT in this study because Savonius rotor has good starting torque coefficient. Based on the wind tunnel tests data, a small scaled combined type SB-VAWT (CSB-VAWT) which has 50W rated power output was designed. The starting torque coefficient, dynamic torque and power performance were analyzed. Both the starting and dynamic torque performance of the CSB-VAWT have been greatly improved according to the simulation results.

  2. Assessing the influence of watershed characteristics on chlorophyll a in waterbodies at global and regional scales

    Science.gov (United States)

    Woelmer, Whitney; Kao, Yu-Chun; Bunnell, David; Deines, Andrew M.; Bennion, David; Rogers, Mark W.; Brooks, Colin N.; Sayers, Michael J.; Banach, David M.; Grimm, Amanda G.; Shuchman, Robert A.

    2016-01-01

    Prediction of primary production of lentic water bodies (i.e., lakes and reservoirs) is valuable to researchers and resource managers alike, but is very rarely done at the global scale. With the development of remote sensing technologies, it is now feasible to gather large amounts of data across the world, including understudied and remote regions. To determine which factors were most important in explaining the variation of chlorophyll a (Chl-a), an indicator of primary production in water bodies, at global and regional scales, we first developed a geospatial database of 227 water bodies and watersheds with corresponding Chl-a, nutrient, hydrogeomorphic, and climate data. Then we used a generalized additive modeling approach and developed model selection criteria to select models that most parsimoniously related Chl-a to predictor variables for all 227 water bodies and for 51 lakes in the Laurentian Great Lakes region in the data set. Our best global model contained two hydrogeomorphic variables (water body surface area and the ratio of watershed to water body surface area) and a climate variable (average temperature in the warmest model selection criteria to select models that most parsimoniously related Chl-a to predictor variables quarter) and explained ~ 30% of variation in Chl-a. Our regional model contained one hydrogeomorphic variable (flow accumulation) and the same climate variable, but explained substantially more variation (58%). Our results indicate that a regional approach to watershed modeling may be more informative to predicting Chl-a, and that nearly a third of global variability in Chl-a may be explained using hydrogeomorphic and climate variables.

  3. The Sensitivity of Characteristics of Large Scale Baroclinic Unstable Waves in Southern Hemisphere to the Underlying Climate

    Directory of Open Access Journals (Sweden)

    Sergei Soldatenko

    2013-01-01

    Full Text Available The sensitivity of the main characteristics of baroclinically unstable waves with respect to fundamental parameters of the atmosphere (the static stability parameter σ0 and vertical shear of a zonal wind Λ is theoretically explored. Two types of waves are considered: synoptic scale waves and planetary scale (ultralong waves based on an Eady-type model and model with vertically averaged primitive equations. Sensitivity functions are obtained that estimate the impact of variations in σ0 and Λ on the growth rate and other characteristics of unstable waves and demonstrate that waves belonging to the short-wave part of the spectrum of unstable waves are more sensitive to changes in the static stability parameter than waves belonging to the long-wave part of the spectrum. The obtained theoretical results show that the increase of the static stability and decrease of the meridional temperature gradient in midlatitude baroclinic zones in some areas of the southern hemisphere lead to a slowing of the growth rate of baroclinic unstable waves and an increasing wavelength of baroclinic unstable wave maximum growth rate, that is, a spectrum shift of unstable waves towards longer wavelengths. These might affect the favorable conditions for the development of baroclinic instability and, therefore, the intensity of cyclone generation activity.

  4. Influence of length parameter on the characteristics of nanoscale titanium oxide memristor%纳米级尺寸参数对钛氧化物忆阻器的特性影响∗

    Institute of Scientific and Technical Information of China (English)

    郭羽泉; 段书凯; 王丽丹

    2015-01-01

    analog computer. With the gradually in-depth study of memristor, memristor is being microsized, and its internal structure, motion law among its internal particles and influences resulting from the parameters are further explored. In recent years, the memristor has made significant achievement in the areas of non-volatile solid-state memory, intelligent storage, very-large-scale integrated circuitry, programmable analog circuits, and artificial neural networks. So far, the influence of size parameter on the memristor has been little studied, although the size parameter is one of the key factors in the memristor fabrication technology, which severely restricts the memristor development and its practical application. In the paper, we theoretically analyze the influences of size parameter on two practical memristor models (i.e., the HP memristor and spintronic memristor) in detail based on the Ohm’s law. On this basis, a series of circuit experimental simulation is carried out, and the corresponding memristor characteristic curves are thus obtained. Furthermore, we choose 4 most representative experimental results, and make specific analysis on them. Those results indicate that the optimal length of HP memristor is in a range from 8 nm to 12 nm, while the proper range of spintronic memristor is from 500 nm to 600 nm. The final results can not only contribute to memristor physical implementation and its applications, but also provide theoretical references and reliable experiment basis for the further development of the titanium oxide memristor devices and the relevant research.

  5. 不同畦长灌溉对小麦耗水特性及产量的影响%Effects of field border length for irrigation on the water consumption characteristics and grain yield of wheat

    Institute of Scientific and Technical Information of China (English)

    马尚宇; 于振文; 王东; 张永丽; 石玉

    2012-01-01

    In the wheat growth seasons of 2009-2010 and 2010-2011, six border lengths of 10, 20, 40, 60, 80 and 100 m were installed in a wheat field to study the effects of different border lengths for irrigation on the water consumption characteristics and grain yield of wheat. The results showed that with the increasing border length from 10 to 80 m, the irrigation amount and the proportion of irrigation amount to total water consumption amount, the water content in 0 - 200 cm soil layers and the soil water supply capacity at anthesis stage, as well as the wheat grain yield and water use efficiency increased, while the soil water consumption amount and the water consumption amount of wheat from jointing to anthesis stages as well as the total water consumption amount decreased. At the border length of <80 m, the irrigation amount was smaller, and the water content in upper soil layers was lower, as compared with those at the border length of 80 m, which led to the wheat to absorb more water from deeper soil layers, and thus, the total water consumption increased. At the border length of 100 m, the irrigation amount, soil water consumption amount, and total water consumption amount all increased, and, due to the excessive irrigation amount and the uneven distribution of irrigation water when irrigated once, the 1000-grain mass, grain yield, and water use efficiency decreased significantly, which was not conductive to the water-saving and high-yield cultivation.%在2009-2010和2010-2011年小麦生长季,设置10、20、40、60、80和100m6个畦田长度,研究不同畦长对小麦耗水特性及产量的影响.结果表明:≤80 m畦长处理下,随畦长的增加,灌水量逐渐增加,灌水量占总耗水量的比例增加,土壤贮水消耗量减少,小麦拔节至开花期的耗水量和生长季总耗水量均减少,开花期0~200 cm各土层土壤含水量增加,土壤供水能力提高,籽粒产量和水分利用效率逐渐提高.与80 m畦长处理相比,<80

  6. Topological characteristics of model gels

    International Nuclear Information System (INIS)

    The Euler characteristic of an object is a topological invariant determined by the number of handles and holes that it contains. Here, we use the Euler characteristic to profile the topology of model three-dimensional gel-forming fluids as a function of increasing length scale. These profiles act as a 'topological fingerprint' of the structure, and can be interpreted in terms of three types of topological events. As model fluids we have considered a system of dipolar dumbbells, and suspensions of adhesive hard spheres with isotropic and patchy interactions in turn. The correlation between the percolation threshold and the length scale on which the Euler characteristic passes through zero is examined and found to be system-dependent. A scheme for the efficient calculation of the Euler characteristic with and without periodic boundary conditions is described.

  7. The meso-scale characteristics of Typhoon Morakot(2009) revealed from polarimetric radar analyses

    Science.gov (United States)

    Wang, T. C.; Tang, Y.; Radar Meteorology Lab.

    2010-12-01

    The record breaking torrential rainfall of typhoon Morakot (2009) had caused serious landslide, flooding and casualty in southern Taiwan. Under a weak steering environmental flow condition, the rather complicate scale interaction between the strong southwestern flow, the relatively large size typhoon circulation and the Taiwan topography may cause a phase locked precipitation pattern. The weather radar network which consists of six Doppler radars, and four dual polarization radars had observed this slow moving typhoon during the whole episode of its influence. The unique structure of this enormous precipitation system can be vividly illustrated from the polarimetric radar variables and three dimensional Doppler synthesis wind field. The convection and wind near the eye wall were relatively weak comparing with the principal rain band near the Bashi strait. On the day of Aug. 8, many strong west-east oriented rain bands near southwestern Taiwan repeatedly formed along the convergence zone of typhoon circulation and southwesterly. These rain bands evolved near the southern edge of the typhoon circulation core and propagated southward or oscillated between lat. 23.5° and 22.5°. Many hot towers were embedded in these rain bands were moving quickly toward island and brought heavy rain . From the Doppler synthesis we found the jet like flow associated the rainband may reach 40 m/sec at lower levels. These fast strands of wind were also a major cause of the upslope enhancement of the convections along mountain slope. The polarimetric radar further provided the microphysical information of the convective and stratiform regions of these devastation rain bands. Within the hot towers,the tall and large reflectivity (Zhh) and specific diffential phase column( Kdp max > 7 degree/km )were associated with very strong vertical velocity (~20m/sec), indicating the huge amount of liquid water content and ice content. The smaller correlation coefficient ( RHOhv) region above the Kdp

  8. On-farm characteristics and biosecurity protocols for small-scale swine producers in eastern Australia.

    Science.gov (United States)

    Schembri, N; Hernandez-Jover, M; Toribio, J-A L M L; Holyoake, P K

    2015-01-01

    Pigs are considered high risk for the introduction and spread of foot and mouth disease (FMD) in Australia. Facilities where animals from different origins are commingled, such as saleyards, pose a high risk for disease spread. Sound on-farm management practices and biosecurity protocols are the first line of defence against a potential on-farm disease outbreak. This study evaluated the practices of 104 producers (vendors who sold pigs and purchasers of live pigs for grow-out) who traded pigs at 6 peri-urban and rural saleyards in eastern Australia. Specifically, management and on-farm biosecurity practices were assessed using an in-depth questionnaire. Univariable and multivariable logistic regression analyses were used to investigate (1) producer associations: producer type, State, motivation to keep pigs, farm type, gender, years having owned pigs, and the acquisition of formal livestock qualifications; and (2) pig associations: herd size, housing, management (husbandry and feeding) practices and biosecurity (including pig movement) practices. Backyard operations (footwear precautions (P=0.007) and ask visitors about prior pig contacts (P=0.004). Approximately 40% of backyard and small-scale producers reported not having any quarantine practices in place for incoming pigs, compared to only 9.1% among larger producers. The main reasons cited for not adopting on-farm biosecurity practices in this study included having no need on their property (43.1%) and a lack of information and support (by the industry and/or authorities; 18.5%). Up to three-quarters of all producers maintained an open breeding herd, regularly introducing new pigs to the main herd. Saleyards are an important source of income for backyard and small-scale producers as well as an important risk factor for the introduction and dissemination of endemic and emerging animal diseases. Differing management and biosecurity practices as well as the motivations of these producers keeping pigs in small

  9. Macropore flow at the field scale: predictive performance of empirical models and X-ray CT analyzed macropore characteristics

    Science.gov (United States)

    Naveed, M.; Moldrup, P.; Schaap, M.; Tuller, M.; Kulkarni, R.; Vögel, H.-J.; Wollesen de Jonge, L.

    2015-11-01

    Predictions of macropore flow is important for maintaining both soil and water quality as it governs key related soil processes e.g. soil erosion and subsurface transport of pollutants. However, macropore flow currently cannot be reliably predicted at the field scale because of inherently large spatial variability. The aim of this study was to perform field scale characterization of macropore flow and investigate the predictive performance of (1) current empirical models for both water and air flow, and (2) X-ray CT derived macropore network characteristics. For this purpose, 65 cylindrical soil columns (6 cm diameter and 3.5 cm height) were extracted from the topsoil (5 to 8.5 cm depth) in a 15 m × 15 m grid from an agricultural loamy field located in Silstrup, Denmark. All soil columns were scanned with an industrial CT scanner (129 μm resolution) and later used for measurements of saturated water permeability, air permeability and gas diffusivity at -30 and -100 cm matric potentials. Distribution maps for both water and air permeabilities and gas diffusivity reflected no spatial correlation irrespective of the soil texture and organic matter maps. Empirical predictive models for both water and air permeabilities showed poor performance as they were not able to realistically capture macropore flow because of poor correlations with soil texture and bulk density. The tested empirical model predicted well gas diffusivity at -100 cm matric potential, but relatively failed at -30 cm matric potential particularly for samples with biopore flow. Image segmentation output of the four employed methods was nearly the same, and matched well with measured air-filled porosity at -30 cm matric potential. Many of the CT derived macropore network characteristics were strongly interrelated. Most of the macropore network characteristics were also strongly correlated with saturated water permeability, air permeability, and gas diffusivity. The correlations between macropore

  10. Influences of NOM composition and bacteriological characteristics on biological stability in a full-scale drinking water treatment plant.

    Science.gov (United States)

    Park, Ji Won; Kim, Hyun-Chul; Meyer, Anne S; Kim, Sungpyo; Maeng, Sung Kyu

    2016-10-01

    The influences of natural organic matter (NOM) and bacteriological characteristics on the biological stability of water were investigated in a full-scale drinking water treatment plant. We found that prechlorination decreased the hydrophobicity of the organic matter and significantly increased the high-molecular-weight (MW) dissolved organic matter, such as biopolymers and humic substances. High-MW organic matter and structurally complex compounds are known to be relatively slowly biodegradable; however, because of the prechlorination step, the indigenous bacteria could readily utilise these fractions as assimilable organic carbon. Sequential coagulation and sedimentation resulted in the substantial removal of biopolymer (74%), humic substance (33%), bacterial cells (79%), and assimilable organic carbon (67%). Rapid sand and granular activated carbon filtration induced an increase in the low-nucleic-acid content bacteria; however, these bacteria were biologically less active in relation to enzymatic activity and ATP. The granular activated carbon step was essential to securing biological stability (the ability to prevent bacterial growth) by removing the residual assimilable organic carbon that had formed during the ozone treatment. The growth potential of Escherichia coli and indigenous bacteria were found to differ in respect to NOM characteristics. In comparison with E. coli, the indigenous bacteria utilised a broader range of NOM as a carbon source. Principal component analysis demonstrated that the measured biological stability of water could differ, depending on the NOM characteristics, as well as on the bacterial inoculum selected for the analysis. PMID:27376858

  11. Seasonal characteristics of the large-scale moisture flux transport over the Arabian Peninsula

    Science.gov (United States)

    Athar, H.; Ammar, K.

    2016-05-01

    The relationship between the lower tropospheric (1000 to 850 hPa) large-scale moisture flux transport and the precipitation over the Arabian Peninsula (AP), on a seasonal basis, using the NCEP-NCAR gridded dataset for the 53-year period (1958-2010), is investigated. The lower tropospheric moisture flux divergence occurs due to the Hadley cell-based descending air over the AP, as well as due to the presence of Somali jet in dry season (June to September) for the southern (≤22° N) AP domain, leading to significantly reduced precipitation in the AP. The AP thus acts more as a net transporter of moisture flux from adjacent Sea areas to nearby regions. The North Atlantic Oscillation (NAO) and the Artic Oscillation (AO) climatic indices are found to modulate significantly the net seasonal moisture flux into the AP region animating from the Mediterranean Sea, and the Arabian Sea, both for the northern (≥22° N) and southern AP domains.

  12. Characteristic Of Induction Magnetic Field On The Laboratory Scale Superconducting Fault Current Limiter Circuit

    International Nuclear Information System (INIS)

    Model construction of the laboratory scale superconducting fault current limiter circuit (SFCL) has been performed. The SFCL is fault current limiter and used as electric network security. It mainly consists of a copper coil, a superconducting ring and an iron core that are concentrically arranged. The SFCL circuit is essentially a transformer where the secondary windings are being replaced by the ring of YBa2Cu3O7-x superconductor (HTS). The ring has critical transition temperature Tc = 92 K and critical current Ic = 3.61 A. Characterization of the SFCL circuit is simulated by ANSYS version 5.4 software. The SFCL circuit consists of load and transformer impedances. The results show that the inductions of magnet field flux in the iron core of primer windings and ring disappear to one other before fault state. It means that impedance of the transformer is zero. After the condition a superconductivity behavior of the ring is disappear so that the impedance of the transformer becomes very high. From this experiment, we concluded that the SFCL circuit could work normally if the resultant of induction magnetic in the iron core (transformer) is zero

  13. Determination of summer monsoon onset and its related large-scale circulation characteristics over Pakistan

    Science.gov (United States)

    Latif, M.; Syed, F. S.

    2016-08-01

    The onset of summer monsoon over the Core Monsoon Region of Pakistan (CMRP) has been investigated in this study using observational daily rainfall and Precipitable Water (PW) data sets. An objective criterion is proposed to define monsoon onset dates by employing Precipitation Index and Normalized Precipitable Water Index techniques. The climatological mean summer monsoon onset dates over CMRP based on daily rainfall data sets are observed to be 1 July and 30 June in the station and gridded data sets, respectively. Whereas the daily PW-based climatological mean onset date is 30 June. The year-wise onset dates determined through station and gridded rainfall data sets are very similar but these dates differ in case of PW-based onsets. The evolution of large-scale circulation anomalies and thermodynamic structure leading monsoon onset over Pakistan shows that a strong positive temperature and geopotential height anomalies appear over the northwestern part of the core region in the upper atmosphere. This warm geopotential height anomaly gets strengthen as the monsoon onset approaches. The temperature anomalies are barotropic whereas the geopotential height anomalies are baroclinic with the presence of low level anticyclone over the Tibetan Plateau. A moisture convergence zone along the foothill of Himalayas and low level moisture convergence zone over the north Arabian Sea set the stage for the moisture carrying monsoon winds to blow inland towards CMRP. The moisture is mainly supplied from the Arabian Sea, as the low pressure system approaches CMRP from the Bay of Bengal.

  14. Calculation and characteristics analysis of blade pitch loads for large scale wind turbines

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Based on the electric pitch system of large scale horizontal-axis wind turbines,the blade pitch loads coming mainly from centrifugal force,aerodynamic force and gravity are analyzed,and the calculation models for them are established in this paper.For illustration,a 1.2 MW wind turbine is introduced as a practical sample,and its blade pitch loads from centrifugal force,aerodynamic force and gravity are calculated and analyzed separately and synthetically.The research results showed that in the process of rotor rotating 360o,the fluctuation of blade pitch loads is similar to cosine curve when the rotor rotational speed,in-flow wind speed and pitch angle are constant.Furthermore,the amplitude of blade pitch load presents quite a difference at a different pitch angle.The ways of calculation for blade pitch loads are of the universality,and are helpful for further research of the individual pitch control system.

  15. Local versus regional-scale characteristics of monsoon onset and post-onset rainfall over Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Moron, Vincent [Aix-Marseille University, CEREGE, UMR 6635 CNRS, Institut Universitaire de France, Aix en Provence (France); Columbia University, IRI, Palisades (United States); Robertson, Andrew W.; Qian, Jian-Hua [Columbia University, IRI, Palisades (United States)

    2010-02-15

    The austral summer monsoon onset and post-onset rainfall and their associated low-level winds are analyzed during the August-February season over Indonesia from 1979 to 2006 using surface and satellite products as well as reanalyses and regional climate model simulations. Onset date is defined using a local agronomic definition. Its leading empirical orthogonal function is found to exhibit a regional-scale spatially-coherent signal across ''monsoonal'' Indonesia, i.e. mostly south of the equator, with an asymmetric temporal behavior, such that delayed onsets are more intense than early ones. Associated anomalies in rainfall tend to weaken quickly after mid-to-late November or early December, especially over islands, while they tend to persist over ocean. This weakening is shown to be associated with the evolution of distinct weather types revealed by a k-means cluster analysis. In particular, late onsets - usually related to warm El Nino Southern oscillation events - are found to be accompanied by an increased prevalence of a weather type characterized by weak low-level daily-averaged winds across monsoonal Indonesia and increased (decreased) rainfall over most of the island orography and southern and western coasts (seas). The regional model simulations provide evidence that this land-sea rainfall contrast could be associated with an enhanced diurnal sea-land breeze circulation. (orig.)

  16. Laboratory scale development of coating for improving characteristics of candidate materials for fusion reactor

    International Nuclear Information System (INIS)

    Application of coatings of refractory low atomic number materials on to different components of Tokamak type controlled thermonuclear reactor are expected to provide a degree of design flexibility. The project envisages to deal with the challenging problem on laboratory scale. Coatings investigated include carbon, beryllium, boron, titanium carbide and alumina and substrates chosen have been 304, 316 stainless steels, monel-400, molybdenum, copper, graphite, etc. For their deposition, different techniques (e.g. evaporation, sputtering and their different variants) have been tried, appropriate ones chosen and their parameters optimized. The coating composition has been analyzed using X-ray diffraction (XRD), Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), Rutherford backscattering analysis (RBS) and secondary ions mass spectroscopy (SIMS). Surface morphology has been studied using scanning electron microscopy (SEM). Sebastian coating adherence tester has been used for adhesion measurement and Wilson's Tukon microhardness tester for their microhardness measurement. The coatings have been subjected to pulses from YAG laser to evaluate their thermal cycling behaviour. Deuterium ion bombardment (Energy: 20-120 keV; doses: 1019-9.3x1020 ions/cm2) behaviour has also been studied. In general, adherent and hard coatings capable of withstanding thermal cycling could be deposited. Out of the coatings studied, titanium carbide shows best results. The following pages are reprints and not mircrofiched: p. 25-32, 39-41, 57-81. Bibliographic description is on page 13

  17. Experimental study on Kolmogorov's length scale in hydraulic jumps of low Froude numbers%低弗劳德数水跃耗散涡尺度的物模研究

    Institute of Scientific and Technical Information of China (English)

    陈帅; 王均星; 陈利强; 罗贝尔

    2013-01-01

    In this model test, a micro acoustic doppler velocimeter was used as the main method for measurements of the structure of hydraulic jumps at Froude numbers of 1.49, 2.51 and 3.35. Turbulence energy dissipation rate is estimated with the inertial dissipation method, and hence the distribution of Kolmogorov's length scale both inside and outside the jump is obtained. It is shown that eddies in the lower range of Kolmogorov's length scale assemble more closely in the developing boundary layer, the recirculation region and the air-water turbulent shear layer, but then they gradually level off along with the jump moving towards downstream. Under this circumstance, Reynolds number, instead of Froude number, is a dominant factor. On the other hand, the Kolmogorov's length scale within the jump decreases nonlinearly with the growth of Froude numbers, and at the same time, these eddies increase in size more rapidly within a certain distance after the jump. Finally, the scale becomes nearly the same over a cross section at a distance of 2. 5 times the jump length from the toe.%采用微型多普勒声学测速仪(micro-ADV)为主要测量手段,对低弗劳德数下(Fr1=1.49、2.51和3.35)的水跃结构进行了物理模型试验研究.运用惯性耗散法(inertial dissipation method)对湍动能耗散率进行了估算,得到了水跃内部和跃后一定范围内耗散涡尺度的分布情况.试验结果显示,水跃旋滚区、紊动剪切层和底部边界层内小尺度的耗散涡分布相对集中,并随着水跃向下游传播逐渐扩散开来,这一特征与弗劳德数的大小无关,此时雷诺数是主要的影响因素.另一方面,水跃内部的耗散涡尺度随着弗劳德数的增大而减小,同时小尺度的耗散涡在跃后一定范围内将具有更快的增长速度,但最终在距跃前断面约2.5倍跃长的位置上,尺度会变为基本一致.

  18. A combined method of small-angle neutron scattering and neutron radiography to visualize water in an operating fuel cell over a wide length scale from nano to millimeter

    International Nuclear Information System (INIS)

    In order to visualize water generated in an operating polymer electrolyte fuel cell (PEFC), a neutron radiography (NR) apparatus, composed of a scintillator, optical mirrors and a CCD camera, was installed at a sample position of the focusing and polarized neutron small-angle scattering (SANS) spectrometer (SANS-J-II) at research reactor JRR-3 at Japan Atomic Energy Agency, Tokai, Japan. By combining SANS and NR, we aim to cover a wide length scale from nanometer to millimeter. The new method succeeded in detecting a spatial distribution of the water generated in individual cell elements; NR detected the water in a gas diffusion layer and a flow field, whereas SANS quantitatively determines the water content in a membrane electrode assembly (MEA).

  19. Variation of aerosol characteristics in the detail scale of time and space

    Science.gov (United States)

    Mukai, S.; Nakata, M.; Sano, I.

    2012-04-01

    -Osaka. We guess dust aerosols are transported over the mountains because dust aerosols exist higher than usual. In order to investigate change of aerosol properties before and after dust event, we analyze particulate matter with scanning electron microscope (SEM) coupled with energy dispersive X-ray analyzer (EDX). It is found from the scaling of particle size and ratio of major and minor axis for PM2.5 sampling on 21 March, 2010 when dust event occurred that at the peak of dust event nonspherical particles with large particle size are dominant. A componential analysis also presents temporal variation of aerosol properties. Sulfur is major component before dust comes but Si becomes major component with dust event.

  20. In situ distributions and characteristics of heavy metals in full-scale landfill layers.

    Science.gov (United States)

    He, Pin-Jing; Xiao, Zheng; Shao, Li-Ming; Yu, Ji-Yu; Lee, Duu-Jong

    2006-10-11

    The leachate from methanogenic landfill normally contains low concentrations of heavy metals. Little samples had ever been collected from the full-scale landfill piles owing to technical difficulty for well drilling. We drilled two wells in Hangzhou Tianziling landfill, 20 m and 32 m in depth each, and collected solid samples of waste age of 1-4 years from both wells. The total amounts, the sequentially extracted amounts, and the chemical binding forms of heavy metals of the samples collected at different depths were measured. With the correlation between leachate production amount and the yearly rainfall amount, the leached ratio of the heavy metals were estimated only 0.13%, 1.8%, 0.15%, and 0.19% of Cu, Cd, Pb, and Zn, respectively. The heavy metals amounts in the main compositions of MSW, like glass, food waste, paper, coal cinders, were measured using fresh MSW samples. Afterward, the contents of heavy metals initially landfilled were estimated. A positive correlation was noted between the measured and the estimated initial contents of heavy metals, indicating that the low migration of heavy metals in landfill layers. However, among the metals investigated, Zn has shown better mobility inside landfill layers. Acid volatile sulfide (AVS) and the simultaneously extracted metals (SEM) were measured for all collected samples with optimal reaction conditions identified to yield nearly perfect sulfide recovery as follows: 100 g wet samples, 80 mL min(-1) N(2) flow rate, reaction time of 150 min. The SEM/AVS ratios ranged 25-45, indicating that the AVS was insufficient to immobilize the SEM. Sequential extraction using six-fraction scheme revealed that the sum of exchangeable and the avid soluble fractions of heavy metals follow: Zn>Cd>Cu, Ni, Pb>Cr. The insoluble fraction of heavy metals in MSW was high, for instance, over 80% for Cr and Pb high insoluble fractions of heavy metals in the landfilled MSW and the sorption capability of the methanogenic landfill layers

  1. Shale gas characteristics of the Lower Toarcian Posidonia Shale in Germany: from basin to nanometre scale

    Science.gov (United States)

    Schulz, Hans-Martin; Bernard, Sylvain; Horsfield, Brian; Krüger, Martin; Littke, Ralf; di primio, Rolando

    2013-04-01

    The Early Toarcian Posidonia Shale is a proven hydrocarbon source rock which was deposited in a shallow epicontinental basin. In southern Germany, Tethyan warm-water influences from the south led to carbonate sedimentation, whereas cold-water influxes from the north controlled siliciclastic sedimentation in the northwestern parts of Germany and the Netherlands. Restricted sea-floor circulation and organic matter preservation are considered to be the consequence of an oceanic anoxic event. In contrast, non-marine conditions led to sedimentation of coarser grained sediments under progressively terrestrial conditions in northeastern Germany The present-day distribution of Posidonia Shale in northern Germany is restricted to the centres of rift basins that formed in the Late Jurassic (e.g., Lower Saxony Basin and Dogger Troughs like the West and East Holstein Troughs) as a result of erosion on the basin margins and bounding highs. The source rock characteristics are in part dependent on grain size as the Posidonia Shale in eastern Germany is referred to as a mixed to non-source rock facies. In the study area, the TOC content and the organic matter quality vary vertically and laterally, likely as a consequence of a rising sea level during the Toarcian. Here we present and compare data of whole Posidonia Shale sections, investigating these variations and highlighting the variability of Posidonia Shale depositional system. During all phases of burial, gas was generated in the Posidonia Shale. Low sedimentation rates led to diffusion of early diagenetically formed biogenic methane. Isochronously formed diagenetic carbonates tightened the matrix and increased brittleness. Thermogenic gas generation occurred in wide areas of Lower Saxony as well as in Schleswig Holstein. Biogenic methane gas can still be formed today in Posidonia Shale at shallow depth in areas which were covered by Pleistocene glaciers. Submicrometric interparticle pores predominate in immature samples. At

  2. Deriving the Characteristic Scale for Effectively Monitoring Heavy Metal Stress in Rice by Assimilation of GF-1 Data with the WOFOST Model

    OpenAIRE

    Zhi Huang; Xiangnan Liu; Ming Jin; Chao Ding; Jiale Jiang; Ling Wu

    2016-01-01

    Accurate monitoring of heavy metal stress in crops is of great importance to assure agricultural productivity and food security, and remote sensing is an effective tool to address this problem. However, given that Earth observation instruments provide data at multiple scales, the choice of scale for use in such monitoring is challenging. This study focused on identifying the characteristic scale for effectively monitoring heavy metal stress in rice using the dry weight of roots (WRT) as the r...

  3. Hydrodynamic and Mass Transfer Characteristics of Annulus-Rising Airlift Reactor – The Effect of Reactor Scale

    Directory of Open Access Journals (Sweden)

    Han Mei

    2016-01-01

    Full Text Available Hydrodynamic and mass transfer characteristics of an annulus-rising airlift reactor (AR_ALR were investigated with experimental and CFD simulation methods. A three-phase Eulerian model was developed to simulate the AR_ALR in three flow regimes. 3D steady state CFD simulations were performed under different gas superficial velocities (Ug. Good agreements on gas holdup and volumetric mass transfer coefficient were obtained over the range of the studied Ug. The three flow regimes in AR_ALR were captured well and are similar to those observed in experiments. The developed CFD model can be used to predict mass transfer and gas holdup in AR_ALRs at different scales

  4. Battery charging characteristics in small scaled photovoltaic system using resonant DC-DC converter with electric isolation

    International Nuclear Information System (INIS)

    The solar energy has been drawing attention of the whole world as a clean and infinite energy, since the globe resource, the globe ecology and so on came into question. The wide applications of the solar energy are being expected in a range from electric power plants to household systems. But the output power induced in the photovoltaic modules is influenced by an intensity of the solar radiation, a temperature of the solar cells and so on, so the various useful forms of the solar energy are being proposed for a purpose of stable power supply. a system described in this paper is a small scaled photovoltaic system with storage batteries. This paper describes the theoretical analyses of the photovoltaic system using a resonant DC-DC converter in order to clarify a desirable circuit condition, besides the experimental results of the battery charging characteristics are presented

  5. Speech Enhancement Algorithm Based on Combining Local Characteristic-Scale Decomposition and Difference Spectrum of Singular Values

    Directory of Open Access Journals (Sweden)

    Nan Li

    2013-06-01

    Full Text Available De-noising of speech signal polluted by background noise, which is of great practical significance for effective transmission and accurate recognition of sound, is important. Local characteristic-scale decomposition is introduced, and it can divide the speech into low- and high-frequency parts without a loss in useful speech. The algorithm accelerates the speed of convergence, as well as pretreatment, and has less illusive component. In addition, two different criteria are proposed to select the reasonable noise reduction order based on the difference spectra of singular values. The proposed approach has improved the problem of noise reduction order selected by experience in singular value decomposition and enhanced de-noising effects. Simulation experiments verify the validity of the algorithm from subjective and objective evaluations.

  6. Meat Quality Characteristics of Small East African Goats and Norwegian Crosses Finished under Small Scale Farming Conditions.

    Science.gov (United States)

    Hozza, W A; Mtenga, L A; Kifaro, G C; Shija, D S N; Mushi, D E; Safari, J G; Shirima, E J M

    2014-12-01

    The aim of the experiment was to study the effect of feeding system on meat quality characteristics of Small East African (SEA) goats and their crosses with Norwegian (SEA×N) goats finished under small scale farming conditions. Twenty four castrated goats at the age of 18 months with live body weight of 16.7±0.54 kg from each breed (SEA and SEA×N) were distributed in a completely randomized design in a 2×3 factorial arrangement (two breed, and three dietary treatments). The dietary treatments were; no access to concentrate (T0), 66% access to ad libitum concentrate allowance (T66) and 100% access to ad libitum concentrate allowance with 20% refusal (T100) and the experimental period was for 84 days. In addition, all goats were allowed to graze for 2 hours daily and later fed grass hay on ad libitum basis. Daily feed intakes were recorded for all 84-days of experiment after which the animals were slaughtered. Feed intake of T100 animals was 536 g/d, which was 183 g/d higher than that of T66 group. Supplemented goats had significantly (p0.05) for dressing percentage and carcass conformation among supplemented goats except fatness score, total fat depots and carcass fat which increased (pmeat dry matter with subsequent increase of fat in the meat. Muscle pH of goats fed concentrate declined rapidly and reached below 6 at 6 h post-mortem but temperature remained at 28°C. Cooking loss and meat tenderness improved (pmeat tenderness improved (pmeat quality characteristics of meat from SEA goats and their crosses with Norwegian breeds finished under small scale farming conditions in rural areas. Therefore, concentrate supplementation of goats of both breeds improves meat quality attributes. PMID:25358372

  7. Summary of calculations of dynamic response characteristics and design stress of the 1/5 scale PSE torus

    International Nuclear Information System (INIS)

    The Lawrence Livermore Laboratory is currently involved in a 1/5 scale testing program on the Mark I BWR pressure suppression system. A key element of the test setup is a pressure vessel that is a 900 sector of a torus. Proper performance of the 900 torus depends on its structural integrity and structural dynamic characteristics. It must sustain the internal pressurization of the planned tests, and its dynamic response to the transient test loads should be minimal. If the structural vibrations are too great, interpretation of important load cell and pressure transducer data will be difficult. The purpose of the report is to bring together under one cover calculations pertaining to the structural dynamic characteristics and structural integrity of 900 torus. The report is divided into the following sections: (1) system description in which the torus and associated hardware are briefly described; (2) structural dynamics in which calculations of natural frequency and dynamic response are presented; and (3) structural integrity in which stress calculations for design purposes are presented; and an appendix which contains an LLL internal report comparing the expected load cell response for a three and four-point supported torus

  8. Analysis of DC Characteristics and Small Signal Equivalent Circuit Parameters of GaAs Metal-Semiconductor Field Effect Transistors with Different Gate Lengths and Different Gate Contours by Two-Dimensional Device Simulations

    Science.gov (United States)

    Meng, C. C.; Su, J. Y.; Yang, S. M.

    2005-09-01

    The gate length and gate contour of a GaAs metal-semiconductor field effect transistor (MESFET) device play important roles in determining the small signal circuit parameters and large signal breakdown voltage behavior. GaAs MESFETs with different gate lengths and gate contours were studied by the two-dimensional (2-D) semiconductor device simulations to investigate the dependence of small signal circuit parameters and breakdown voltage on gate length and gate contour. The results show that gate length affects small-signal circuit parameter Cgs while gate contour affects Cgd. The breakdown voltage has strong dependence on gate contour and little dependence on gate length.

  9. Atomic frequency-time-length standards

    International Nuclear Information System (INIS)

    The principles of operative of atomic frequency-time-length standards and their principle characteristics are described. The role of quartz crystal oscillators which are sloved to active or passive standards is presented. (authors)

  10. Suppressed black hole production from minimal length

    International Nuclear Information System (INIS)

    Large extra dimensions lower the Planck scale to values soon accessible. Motivated by string theory, the models of large extra dimensions predict a vast number of new effects in the energy range of the lowered Planck scale, among them the production of TeV-mass black holes. But not only is the Planck scale the energy scale at which effects of modified gravity become important. String theory as well as non-commutative quantum mechanics suggest that the Planck length acts a minimal length in nature, providing a natural ultraviolet cutoff and a limit to the possible resolution of spacetime. The minimal length effects thus become important in the same energy range in which the black holes are expected to form. In this Letter we examine the influence of the minimal length on the expected production rate of the black holes

  11. Realtime Prediction in Disturbed Landscapes: Identifying Highest Priority Disturbance Characteristics Impacting Streamflow Response in a CONUS-Scale Operational Model

    Science.gov (United States)

    Dugger, A. L.; Gochis, D. J.; Yu, W.; McCreight, J. L.; Barlage, M. J.

    2015-12-01

    The "next generation" of hydrologic prediction systems - targeting unified, process-based, real-time prediction of the total water cycle - bring with them an increased need for real-time land surface characterization. Climatologically-derived estimates may perform well under stationary conditions, however disturbance can significantly alter hydrologic behavior and may be poorly represented by mean historical conditions. Fortunately, remote sensing and on-the-ground observation networks are collecting snapshots of these land characteristics over an increasing fraction of the globe. Given the computing constraints of operating a large-domain, real-time prediction system, to take advantage of these data streams we need a way to prioritize which landscape characteristics are most important to hydrologic prediction post-disturbance. To address this need, we setup a model experiment over the contiguous US using the community WRF-Hydro system with the NoahMP land surface model to assess the value of incorporating various aspects of disturbed landscapes into a real-time streamflow prediction model. WRF-Hydro will serve as the initial operational model for the US National Weather Service's new national water prediction effort, so use of WRF-Hydro allows us to leverage both an existing CONUS-scale model implementation and a short research-to-operations path. We first identify USGS GAGES-II basins that experienced more than 25% forest loss between 2000 and 2013. Based on basin disturbance type, geophysical setting, and climate regime, we formulate a conceptual model of which "disturbed" landscape characteristics we expect to dominate streamflow response. We test our conceptual model using WRF-Hydro by modeling a baseline (no disturbance) case, and then bringing in empirically-derived model state shifts representing key disturbance characteristics (e.g., leaf area index, rooting depth, overland roughness, surface detention). For each state update and each basin, we quantify

  12. Evaporation characteristics of a hydrophilic surface with micro-scale and/or nano-scale structures fabricated by sandblasting and aluminum anodization

    International Nuclear Information System (INIS)

    This paper presents the results of evaporation experiments using water droplets on aluminum sheets that were either smooth or had surface structures at the micro-scale, at the nano-scale or at both micro- and nano-scales (dual-scale). The smooth surface was a polished aluminum sheet; the surface with micro-scale structures was obtained by sandblasting; the surface with nano-scale structures was obtained using conventional aluminum anodization and the surface with dual-scale structures was prepared using sandblasting and anodization sequentially. The wetting properties and evaporation rates were measured for each surface. The evaporation rates were affected by their static and dynamic wetting properties. Evaporation on the surface with dual-scale structures was fastest and the evaporation rate was analyzed quantitatively.

  13. Deriving the Characteristic Scale for Effectively Monitoring Heavy Metal Stress in Rice by Assimilation of GF-1 Data with the WOFOST Model

    Directory of Open Access Journals (Sweden)

    Zhi Huang

    2016-03-01

    Full Text Available Accurate monitoring of heavy metal stress in crops is of great importance to assure agricultural productivity and food security, and remote sensing is an effective tool to address this problem. However, given that Earth observation instruments provide data at multiple scales, the choice of scale for use in such monitoring is challenging. This study focused on identifying the characteristic scale for effectively monitoring heavy metal stress in rice using the dry weight of roots (WRT as the representative characteristic, which was obtained by assimilation of GF-1 data with the World Food Studies (WOFOST model. We explored and quantified the effect of the important state variable LAI (leaf area index at various spatial scales on the simulated rice WRT to find the critical scale for heavy metal stress monitoring using the statistical characteristics. Furthermore, a ratio analysis based on the varied heavy metal stress levels was conducted to identify the characteristic scale. Results indicated that the critical threshold for investigating the rice WRT in monitoring studies of heavy metal stress was larger than 64 m but smaller than 256 m. This finding represents a useful guideline for choosing the most appropriate imagery.

  14. Deriving the Characteristic Scale for Effectively Monitoring Heavy Metal Stress in Rice by Assimilation of GF-1 Data with the WOFOST Model.

    Science.gov (United States)

    Huang, Zhi; Liu, Xiangnan; Jin, Ming; Ding, Chao; Jiang, Jiale; Wu, Ling

    2016-01-01

    Accurate monitoring of heavy metal stress in crops is of great importance to assure agricultural productivity and food security, and remote sensing is an effective tool to address this problem. However, given that Earth observation instruments provide data at multiple scales, the choice of scale for use in such monitoring is challenging. This study focused on identifying the characteristic scale for effectively monitoring heavy metal stress in rice using the dry weight of roots (WRT) as the representative characteristic, which was obtained by assimilation of GF-1 data with the World Food Studies (WOFOST) model. We explored and quantified the effect of the important state variable LAI (leaf area index) at various spatial scales on the simulated rice WRT to find the critical scale for heavy metal stress monitoring using the statistical characteristics. Furthermore, a ratio analysis based on the varied heavy metal stress levels was conducted to identify the characteristic scale. Results indicated that the critical threshold for investigating the rice WRT in monitoring studies of heavy metal stress was larger than 64 m but smaller than 256 m. This finding represents a useful guideline for choosing the most appropriate imagery. PMID:26959033

  15. Rain characteristics and large-scale environments of precipitation objects with extreme rain volumes from TRMM observations

    Science.gov (United States)

    Zhou, Yaping; Lau, William K. M.; Liu, Chuntao

    2013-09-01

    This study adopts a "precipitation object" approach by using 14 years of Tropical Rainfall Measuring Mission (TRMM) Precipitation Feature (PF) and National Centers for Environmental Prediction (NCEP) reanalysis data to study rainfall structure and environmental factors associated with extreme heavy rain events. Characteristics of instantaneous extreme volumetric PFs are examined and compared to those of intermediate and small systems. It is found that instantaneous PFs exhibit a much wider scale range compared to the daily gridded precipitation accumulation range. The top 1% of the rainiest PFs contribute over 55% of total rainfall and have 2 orders of rain volume magnitude greater than those of the median PFs. We find a threshold near the top 10% beyond which the PFs grow exponentially into larger, deeper, and colder rain systems. NCEP reanalyses show that midlevel relative humidity and total precipitable water increase steadily with increasingly larger PFs, along with a rapid increase of 500 hPa upward vertical velocity beyond the top 10%. This provides the necessary moisture convergence to amplify and sustain the extreme events. The rapid increase in vertical motion is associated with the release of convective available potential energy (CAPE) in mature systems, as is evident in the increase in CAPE of PFs up to 10% and the subsequent dropoff. The study illustrates distinct stages in the development of an extreme rainfall event including (1) a systematic buildup in large-scale temperature and moisture, (2) a rapid change in rain structure, (3) explosive growth of the PF size, and (4) a release of CAPE before the demise of the event.

  16. Scaling characteristics of ULF geomagnetic fields at the Guam seismoactive area and their dynamics in relation to the earthquake

    Directory of Open Access Journals (Sweden)

    N. Smirnova

    2001-01-01

    Full Text Available The long-term evolution of scaling (fractal characteristics of the ULF geomagnetic fields in the seismoactive region of the Guam Island is studied in relation to the strong (Ms = 8.0 nearby earthquake of 8 August 1993. The selected period covers 10 months before and 10 months after the earthquake. The FFT procedure, Burlaga-Klein approach and Higuchi method, have been applied to calculate the scaling exponents and fractal dimensions of the ULF time series. It is found that the spectrum of ULF emissions exhibits, on average, a power law behaviour S(f α f -b , which is a fingerprint of the typical fractal (self-affine time series. The spectrum slope b fluctuates quasi-periodically during the course of time in a range of b = 2.5–0.7, which corresponds to the fractional Brownian motion with both persistent and antipersistent behaviour. An tendency is also found for the spectrum slope to decrease gradually when approaching the earthquake date. Such a tendency manifests itself at all local times, showing a gradual evolution of the structure of the ULF noise to a typical flicker noise structure in proximity to the large earthquake event. We suggest considering such a peculiarity as an earthquake precursory signature. One more effect related to the earthquake is revealed: the longest quasi-period, which is 27 days, disappeared from the variations of the ULF emission spectrum slope during the earthquake, and it reappeared three months after the event. Physical interpretation of the peculiarities revealed has been done on the basis of the SOC (self-organized criticality concept.

  17. Rain Characteristics and Large-Scale Environments of Precipitation Objects with Extreme Rain Volumes from TRMM Observations

    Science.gov (United States)

    Zhou, Yaping; Lau, William K M.; Liu, Chuntao

    2013-01-01

    This study adopts a "precipitation object" approach by using 14 years of Tropical Rainfall Measuring Mission (TRMM) Precipitation Feature (PF) and National Centers for Environmental Prediction (NCEP) reanalysis data to study rainfall structure and environmental factors associated with extreme heavy rain events. Characteristics of instantaneous extreme volumetric PFs are examined and compared to those of intermediate and small systems. It is found that instantaneous PFs exhibit a much wider scale range compared to the daily gridded precipitation accumulation range. The top 1% of the rainiest PFs contribute over 55% of total rainfall and have 2 orders of rain volume magnitude greater than those of the median PFs. We find a threshold near the top 10% beyond which the PFs grow exponentially into larger, deeper, and colder rain systems. NCEP reanalyses show that midlevel relative humidity and total precipitable water increase steadily with increasingly larger PFs, along with a rapid increase of 500 hPa upward vertical velocity beyond the top 10%. This provides the necessary moisture convergence to amplify and sustain the extreme events. The rapid increase in vertical motion is associated with the release of convective available potential energy (CAPE) in mature systems, as is evident in the increase in CAPE of PFs up to 10% and the subsequent dropoff. The study illustrates distinct stages in the development of an extreme rainfall event including: (1) a systematic buildup in large-scale temperature and moisture, (2) a rapid change in rain structure, (3) explosive growth of the PF size, and (4) a release of CAPE before the demise of the event.

  18. Full-scale prototyping of the Hitachi dual-purpose metal cask and verification of its heat transfer characteristics

    International Nuclear Information System (INIS)

    Hitachi has been developing dual-purpose metal casks for transport and storage of spent nuclear fuels. The Hitachi cask, HDP69B can store 69 BWR fuel assemblies. The cask features are as follows. 1) The fuel basket is assembled mainly with plates of borated stainless steel. The plates are not welded, but cross-inserted into each other like the dividers in an egg carton. Since the borated stainless steel has relatively low heat conductivity, aluminum alloy plates are inserted along with some stainless steel plates to enhance heat removal ability. 2) Cured resin blocks are fitted into the inner shell of the cask for neutron shielding of the cask body. The resin blocks are surrounded by an aluminum casing which transfers heat of stored fuel from the inner shell to the outer shell of the cask. The block type shield structure eliminates the need for welding the heat transfer fins to the inner and outer shells. The weldless structures of the HDP69B lead to its enhanced manufacturability, but they complicate the heat transfer characteristics because there are gaps between such components as the aluminum casing and inner/outer shells. We carried out full-scale prototyping of the HDP69B and ran a heat transfer test using the prototype. The purposes of the heat transfer test were to check the heat removal ability of the HDP69B and to verify the safety analysis model for heat removal. Results of the heat transfer test and optimized analysis model for heat transfer characteristics of the HDP69B are the focus of this paper. The heat transfer test is summarized as follows. Sixty nine heaters simulating the shape and heat power of spent fuel assemblies were inserted into the fuel basket. After replacing the inner atmosphere with 0.1 MPa of helium, the heat transfer test was started. About 7 days were required to equilibrate the temperature distribution. The temperature at the center of the basket was 194 C. The results confirmed the HDP69B had sufficient heat removal ability. The

  19. Full-scale prototyping of the Hitachi dual-purpose metal cask and verification of its heat transfer characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Kumagai, N.; Ishida, N.; Ootsuka, M.; Kamoshida, M.; Hiranuma, T.; Doumori, S.; Hoshikawa, T.; Shimizu, M.; Kashiwakura, J.; Hayashi, M. [Hitachi, Ltd., Hitachi (Japan)

    2004-07-01

    Hitachi has been developing dual-purpose metal casks for transport and storage of spent nuclear fuels. The Hitachi cask, HDP69B can store 69 BWR fuel assemblies. The cask features are as follows. 1) The fuel basket is assembled mainly with plates of borated stainless steel. The plates are not welded, but cross-inserted into each other like the dividers in an egg carton. Since the borated stainless steel has relatively low heat conductivity, aluminum alloy plates are inserted along with some stainless steel plates to enhance heat removal ability. 2) Cured resin blocks are fitted into the inner shell of the cask for neutron shielding of the cask body. The resin blocks are surrounded by an aluminum casing which transfers heat of stored fuel from the inner shell to the outer shell of the cask. The block type shield structure eliminates the need for welding the heat transfer fins to the inner and outer shells. The weldless structures of the HDP69B lead to its enhanced manufacturability, but they complicate the heat transfer characteristics because there are gaps between such components as the aluminum casing and inner/outer shells. We carried out full-scale prototyping of the HDP69B and ran a heat transfer test using the prototype. The purposes of the heat transfer test were to check the heat removal ability of the HDP69B and to verify the safety analysis model for heat removal. Results of the heat transfer test and optimized analysis model for heat transfer characteristics of the HDP69B are the focus of this paper. The heat transfer test is summarized as follows. Sixty nine heaters simulating the shape and heat power of spent fuel assemblies were inserted into the fuel basket. After replacing the inner atmosphere with 0.1 MPa of helium, the heat transfer test was started. About 7 days were required to equilibrate the temperature distribution. The temperature at the center of the basket was 194 C. The results confirmed the HDP69B had sufficient heat removal ability. The

  20. Nutrient removal performance and microbial characteristics of a full-scale IFAS-EBPR process treating municipal wastewater.

    Science.gov (United States)

    Bai, Yang; Zhang, Yaobin; Quan, Xie; Chen, Shuo

    2016-01-01

    This work describes the nutrient removal performance and microbial characteristics of a full-scale integrated fixed-film activated sludge-enhanced biological phosphorus removal (IFAS-EBPR) process for municipal wastewater treatment. The polymerase chain reaction-denaturing gradient gel electrophoresis results showed that the presence of bacteria in this process, including Nitrosomonas sp., Nitrospira sp., Nitrobacter sp., Pseudomonas sp. and Acinetobacter sp., clusters. The fluorescence in situ hybridization results implied that there were more nitrifiers and denitrifiers on the biofilm carriers than in the suspended sludge, whereas more phosphorus-accumulating organisms (PAOs) resided in the suspended sludge. With the cooperation of these functional microbial populations both on the biofilm carriers and in the suspended sludge, the chemical oxygen demand (COD), NH4(+)-N, total nitrogen (TN) and total phosphorus (TP) removal efficiencies were maintained at 84, 97, 70 and 81%, and the effluent concentrations of them averaged 30, 1.0, 11.5 and 0.6 mg/L, which all satisfy the Chinese discharge standard (COD <50 mg/L, NH4(+)-N <5 mg/L, TN <15 mg/L and TP <1 mg/L), respectively. Therefore, the IFAS-EBPR process is a reliable and effective process for nutrient removal. PMID:27003065

  1. Longitudinal Control Characteristics of a 1/20-Scale Model of the Convair F-102 Airplane at Transonic Speeds

    Science.gov (United States)

    Osborne, Robert S.; Tempelmeyer, Kenneth E.

    1954-01-01

    The effects of elevator deflections from 0deg to -20deg on the force and moment characteristics of a 1/20-scale model of the Convair F-102 airplane with chordwise fences have been determined a t Mach numbers from 0.6 to 1.1 for angles of attack up to 20deg in the Langley 8-foot transonic tunnel. The configuration exhibited static longitudinal stability throughout the range tested, although a mild pitch-up tendency was indicated a t Mach numbers from 0.85 to 0.95. Elevator pitch effectiveness decreased rapidly between the Mach numbers of 0.9 and 1.0, however, no complete loss or reversal was indicated for all conditions tested. Because of the type of longitudinal control used, trimming the configuration from the zero elevator condition resulted in substantial decreases in lift-curve slope and maximum lift-drag ratio and increases in drag due to lift. The drag at zero lift, drag due to lift, and trim drag were high for this configuration.

  2. Multi-scale factors influencing the characteristics of avian communities in urban parks across Beijing during the breeding season

    Science.gov (United States)

    Xie, Shilin; Lu, Fei; Cao, Lei; Zhou, Weiqi; Ouyang, Zhiyun

    2016-07-01

    Understanding the factors that influence the characteristics of avian communities using urban parks at both the patch and landscape level is important to focus management effort towards enhancing bird diversity. Here, we investigated this issue during the breeding season across urban parks in Beijing, China, using high-resolution satellite imagery. Fifty-two bird species were recorded across 29 parks. Analysis of residence type of birds showed that passengers were the most prevalent (37%), indicating that Beijing is a major node in the East Asian–Australasian Flyway. Park size was crucial for total species abundance, but foliage height diversity was the most important factor influencing avian species diversity. Thus, optimizing the configuration of vertical vegetation structure in certain park areas is critical for supporting avian communities in urban parks. Human visitation also showed negative impact on species diversity. At the landscape level, the percentage of artificial surface and largest patch index of woodland in the buffer region significantly affected total species richness, with insectivores and granivores being more sensitive to the landscape pattern of the buffer region. In conclusion, urban birds in Beijing are influenced by various multi-scale factors; however, these effects vary with different feeding types.

  3. Einstein's Length Concept

    International Nuclear Information System (INIS)

    Einstein's length measuring procedure of a rod moving with velocity υ (0 ≤ |υ| < c) is discussed. The part of this procedure, namely measuring the length of the resting (υ = 0) rod, is realizable and leads to the elongation of the moving rod. The other part of Einstein's procedure, measuring the length of the moving (υ ≠ 0) rod, is not realizable and leads to the contraction of the moving rod. As the result of this procedure the moving rod contraction concept is supposed physically unfounded. (author). 8 refs; 1 fig

  4. Appearance of a Minimal Length in e+e- Annihilation

    International Nuclear Information System (INIS)

    Experimental data reveal with a 5σ significance the existence of a characteristic minimal length le=1.57×10-17 cm at the scale E=1.253 TeV in the annihilation reaction e+e-→γγ(γ). Nonlinear electrodynamics coupled to gravity and satisfying the weak energy condition predicts, for an arbitrary gauge invariant Lagrangian, the existence of spinning charged electromagnetic soliton asymptotically Kerr-Newman for a distant observer with the gyromagnetic ratio g=2. Its internal structure includes a rotating equatorial disk of de Sitter vacuum which has properties of a perfect conductor and ideal diamagnetic, displays superconducting behavior, supplies a particle with the finite positive electromagnetic mass related to breaking of space-time symmetry, and gives some idea about the physical origin of a minimal length in annihilation

  5. Spectral Characteristics of Landslide Induced Seismicity: Experimental Validation Based on the Use of an Up-Scaled Sheer Box

    Science.gov (United States)

    Yfantis, G.; Carvajal, H. E. M.; Pytharouli, S.; Lunn, R. J.

    2014-12-01

    Microseismic monitoring has been used for the last 20 years as a tool to understand the landslide mechanisms and to help develop a methodology able to provide real time information regarding landslide behavior. These studies involve deployment of seismic sensors at active slopes, with data usually analyzed and interpreted along with data obtained using other monitoring methods, e.g. geodetic/geotechnical monitoring. The interpretation of the records is based on a number of assumptions regarding the nature of the recorded signals resulting in big uncertainties. In order to overcome this problem, we use an up-scaled sheer box to reproduce seismic signals as those emitted by the movement of a landslide. The experimental set up consists of a 65cm diameter and 50cm high concrete cylinder filled with unsaturated soil. The cylinder is pulled along a surficial corridor with the same type of soil under varying vertical loading conditions and the friction at the interface between the soil in cylinder and soil on corridor emits seismic signals. The signals are recorded by a network of 7 short period 3D seismic sensors at distances ranging from 4 to 15m from the cylinder. We analyse the recorded signals in the frequency and time-frequency domain. The obtained significant frequencies range up to 120Hz. Their amplitude changes depending on the source-to-sensor distance (attenuation effect) and the applied vertical load (simulating different depths of the failure plane). The spectral characteristics of the emitted signals when compared to those of signals emitted from a vertical face failure in very similar geological and loading conditions at a nearby site are consistent. Therefore, this experimental set-up is a good analogue for the study of landslide induced seismicity. The suggested methodology can be a powerful tool in studying the effects of the type of soil, the loading conditions on the failure plane, the degree of saturation and compaction of the soil on signals recorded

  6. A Large Scale Study of the Psychometric Characteristics of the IBR Modified Overt Aggression Scale: Findings and Evidence for Increased Self-Destructive Behaviors in Adult Females with Autism Spectrum Disorder

    Science.gov (United States)

    Cohen, Ira L.; Tsiouris, John A.; Flory, Michael J.; Kim, Soh-Yule; Freedland, Robert; Heaney, Glenn; Pettinger, Jill; Brown, W. Ted

    2010-01-01

    The psychometric characteristics of the IBR Modified Overt Aggression Scale were studied in over 2,000 people with Intellectual Disability (ID). Reliability ranged from good to excellent. Aggression toward others and objects was highest in the youngest adults, in those in the moderate to severe range of ID, and in those with an autism spectrum…

  7. Evaluation of Landing Characteristics Achieved by Simulations and Flight Tests on a Small-scaled Model Related to Magnetically Levitated Advanced Take-off and Landing Operations

    NARCIS (Netherlands)

    Rohacs, D.; Voskuijl, M.; Siepenkotter, N.

    2014-01-01

    The goal of this paper is to simulate and measure on a small-scaled model the landing characteristics related to take-off and landing (TOL) operations supported by a magnetic levitation (MAGLEV) system as ground-based power supply. The technical feasibility and the potential benefits of using ground

  8. Aerodynamic Characteristics of a 0.04956-Scale Model of the Convair F-102A Airplane at Transonic Speeds

    Science.gov (United States)

    Tempelmeyer, Kenneth E.; Osborne, Robert S.

    1955-01-01

    Tests have been conducted in the Langley 8-foot transonic tunnel on a 0.04956-scale model of the Convair F-102A airplane which employed an indented and extended fuselage, cambered wing leading edges, and deflected wing tips. Force and moment characteristics were obtained for Mach numbers from 0.60 to 1.135 at angles of attack up to 20 . In addition, tests were made over a limited angle-of-attack range to determine the effects of the cambered leading edges, deflected tips, and a nose section with a smooth area distribution. Fuselage modifications employed on the F-102A were responsible for a 25.percent reduction in the minimum drag-coefficient rise between the Mach numbers of 0.85 and 1.075 when compared with that for the earlier versions of the F-102. Although the wing modifications increased the F-102A subsonic minimum drag-coefficient level approximately 0.0020, they produced large decreases in drag at lifting conditions over that for the original (plane-wing) F-102. The F-102A had 15 to 25 percent higher maximum lift-drag ratios than did the original F-102. The F-102A had about 15 percent lower maximum lift-drag ratios at Mach numbers below 0.95 and slightly higher maximum lift-drag ratios at supersonic speeds when compared with those ratios for sn earlier modified-wing version of the F-102. Chordwise wing fences which provided suitable longitudinal stability for the original F-102 were not adequate for the cambered-wing F-102A The pitching-moment curves indicated a region of near neutral stability with possible pitch-up tendencies for the F-102A at high subsonic Mach numbers for lift coefficients between about 0.4 and 0.5.

  9. [Spatial discharge characteristics and total load control of non-point source pollutants based on the catchment scale].

    Science.gov (United States)

    Wang, Xia-Hui; Lu, Jun; Zhang, Qing-Zhong; Wang, Bo; Yao, Rui-Hua; Zhang, Hui-Yuan; Huang, Feng

    2011-09-01

    Agricultural non-point source pollution is one of the major causes of water quality deterioration. Based on the analysis of the spatial discharge characteristics and intensity of major pollutants from the agricultural pollution source, the establishment of spatial management subzones for controlling agricultural non-point pollution and a design of a plan for total load control of pollutants from each subzone is an important way to improve the efficiency of control measures. In this paper the Four Lake basin in Hubei Province is adopted as the research case region and a systematic research of the control countermeasures of agricultural non-point pollution based on the catchment scale is carried out. The results shows that in the Four Lake basin, the COD, total nitrogen, total phosphorus and ammonia nitrogen load of the water environment are mainly caused by agricultural non-point pollution. These four kinds of non-point source pollutants respectively account for 67.6%, 82.2%, 84.7% and 50.9% of the total pollutant discharge amount in the basin. The analysis of the spatial discharge characteristics of non-point source pollutants in the Four Lake basin shows that the major contributor source regions of non-point source pollutant in the basin are the four counties, including Honghu, Jianli, Qianjiang and Shayang where the aquatic and livestock production are relatively developed. According to the spatial discharge characteristics of the pollutants and the evaluation of the discharge intensity of pollutants, the Four Lake basin is divided into three agricultural non-point pollution management subzones, which including Changhu upstream aquatic and livestock production pollution control subzone, Four-lake trunk canal rural non-point source pollution control subzone and Honghu aquatic production pollution control subzone. Specific pollution control measures are put forward for each subzone. With a comprehensive consideration of the water quality amelioration and the

  10. Growing correlation length on cooling below the onset of caging in a simulated glass-forming liquid

    DEFF Research Database (Denmark)

    Lačević, N.; Starr, F. W.; Schrøder, Thomas;

    2002-01-01

    We present a calculation of a fourth-order, time-dependent density correlation function that measures higher-order spatiotemporal correlations of the density of a liquid. From molecular dynamics simulations of a glass-forming Lennard-Jones liquid, we find that the characteristic length scale of...... nature of the dynamics of the liquid in the alpha-relaxation regime....

  11. A New Method for Measuring the Stitch Length of Weft Knitted Fabricin a Static Environment

    Institute of Scientific and Technical Information of China (English)

    CHEN Li; SONG Guang-li

    2007-01-01

    It is essential to measure the stitch length of weft knitted fabric in a static environment for economy and improving productivity. The image inputted was dealt with the digital image processing techniques: the paper carded out the transformation of grey scale; then removed impurities with media filtering; the characteristic of the stitch structure was abstracted by using the Fourier transform technique. To obtain the stitch length more accurately, we should establish a geometric model of the stitch based on the digital image processing, which provides a way to transform the stitch length in the two-dimension space into a three-dimension space. This study provides a new method for measuring the stitch length without damaging the fabric.

  12. Flux saturation length of sediment transport

    OpenAIRE

    Pähtz, T.; Kok, JF; Parteli, EJR; Herrmann, HJ

    2013-01-01

    Sediment transport along the surface drives geophysical phenomena as diverse as wind erosion and dune formation. The main length-scale controlling the dynamics of sediment erosion and deposition is the saturation length $L_\\mathrm{s}$, which characterizes the flux response to a change in transport conditions. Here we derive, for the first time, an expression predicting $L_\\mathrm{s}$ as a function of the average sediment velocity under different physical environments. Our expression accounts ...

  13. The German version of the Perceived Stress Scale – psychometric characteristics in a representative German community sample

    OpenAIRE

    Klein, Eva M.; Brähler, Elmar; Dreier, Michael; Reinecke, Leonard; Müller, Kai W.; Schmutzer, Gabriele; Wölfling, Klaus; Beutel, Manfred E.

    2016-01-01

    Background The Perceived Stress Scale Cohen (J Health Soc Behav 24:385-96, 1983) is a widely and well-established self-report scale measuring perceived stress. However, the German version of the PSS-10 has not yet been validated. Thus, the purposes of this representative study were to psychometrically evaluate the PSS-10, and to provide norm values for the German population. Methods The PSS-10 and standardized scales of depression, anxiety, fatigue, procrastination and life satisfaction were ...

  14. Buoyancy effects on the scaling characteristics of atmospheric boundary-layer wind fields in the mesoscale range.

    Science.gov (United States)

    Kiliyanpilakkil, V P; Basu, S; Ruiz-Columbié, A; Araya, G; Castillo, L; Hirth, B; Burgett, W

    2015-09-01

    We have analyzed long-term wind speed time series from five field sites up to a height of 300 m from the ground. Structure function-based scaling analysis has revealed that the scaling exponents in the mesoscale regime systematically depend on height. This anomalous behavior is likely caused by the buoyancy effects. In the framework of the extended self-similarity, the relative scaling exponents portray quasiuniversal behavior. PMID:26465554

  15. The influence of watershed characteristics on spatial patterns of trends in annual scale streamflow variability in the continental U.S.

    Science.gov (United States)

    Rice, Joshua S.; Emanuel, Ryan E.; Vose, James M.

    2016-09-01

    As human activity and climate variability alter the movement of water through the environment the need to better understand hydrologic cycle responses to these changes has grown. A reasonable starting point for gaining such insight is studying changes in streamflow given the importance of streamflow as a source of renewable freshwater. Using a wavelet assisted method we analyzed trends in the magnitude of annual scale streamflow variability from 967 watersheds in the continental U.S. (CONUS) over a 70 year period (1940-2009). Decreased annual variability was the dominant pattern at the CONUS scale. Ecoregion scale results agreed with the CONUS pattern with the exception of two ecoregions closely divided between increases and decreases and one where increases dominated. A comparison of trends in reference and non-reference watersheds indicated that trend magnitudes in non-reference watersheds were significantly larger than those in reference watersheds. Boosted regression tree (BRT) models were used to study the relationship between watershed characteristics and the magnitude of trends in streamflow. At the CONUS scale, the balance between precipitation and evaporative demand, and measures of geographic location were of high relative importance. Relationships between the magnitude of trends and watershed characteristics at the ecoregion scale exhibited differences from the CONUS results and substantial variability was observed among ecoregions. Additionally, the methodology used here has the potential to serve as a robust framework for top-down, data driven analyses of the relationships between changes in the hydrologic cycle and the spatial context within which those changes occur.

  16. Characteristics of oxide scale formed on Cu-bearing austenitic stainless steel during early stages of high temperature oxidation

    Science.gov (United States)

    Swaminathan, Srinivasan; Krishna, Nanda Gopala; Kim, Dong-Ik

    2015-10-01

    Oxide scale evolution on Cu-bearing austenitic stainless steel 304H at 650 °C, in ambient air, for exposure times 100, 300, 500 and 1000 h, has been investigated. Surface morphology and chemistry of the oxide scale grown were examined using SEM/EDX and XPS. The oxidation kinetics was determined by measuring the weight change using an electronic balance. At the initial stage, up to 500 h of exposure time, the oxidation rate was rapid due to surface reactions governed primarily by oxygen ingress, and then, dropped to a low rate after prolonged oxidation for 1000 h. The diffusion of reactants through the initially formed oxide scale limits the oxidation rate at longer times, thus, the progress of reaction followed the parabolic kinetics. The formed oxide scale was enriched significantly with segregation and subsequent oxidation of Nb, and finely dispersed metallic Cu particles. Within the time frame of oxidation, the oxide scale was mainly composed of mixed oxides such as FeCr2O4 and MnCr2O4 along with the binary oxides of Fe, Cr and Mn. Moreover, the precipitation fraction of Cu-rich particles on the oxide scale increased markedly with increase of exposure times. The chemical heterogeneity of oxide scale suggests that the oxidation occurred in a non-selective manner.

  17. Spatial-Scale Characteristics of Precipitation Simulated by Regional Climate Models and the Implications for Hydrological Modeling

    DEFF Research Database (Denmark)

    Rasmussen, S.H.; Christensen, J. H.; Drews, Martin;

    2012-01-01

    precipitation for the central United States. On local scales, gridded precipitation observations and simulated precipitation are compared for the period of the 1987 First International Satellite Land Surface Climatological Project Field Experiment (FIFE) campaign. The results show that spatial correlation......, reflecting larger predictive certainty of the RCMs at larger scales. The findings on aggregated grid scales are shown to be largely independent of the underlying RCMs grid resolutions but not of the overall size of RCM domain. With regard to hydrological modeling applications, these findings indicate that...

  18. Relativistic length agony continued

    Directory of Open Access Journals (Sweden)

    Redžić D.V.

    2014-01-01

    Full Text Available We made an attempt to remedy recent confusing treatments of some basic relativistic concepts and results. Following the argument presented in an earlier paper (Redžić 2008b, we discussed the misconceptions that are recurrent points in the literature devoted to teaching relativity such as: there is no change in the object in Special Relativity, illusory character of relativistic length contraction, stresses and strains induced by Lorentz contraction, and related issues. We gave several examples of the traps of everyday language that lurk in Special Relativity. To remove a possible conceptual and terminological muddle, we made a distinction between the relativistic length reduction and relativistic FitzGerald-Lorentz contraction, corresponding to a passive and an active aspect of length contraction, respectively; we pointed out that both aspects have fundamental dynamical contents. As an illustration of our considerations, we discussed briefly the Dewan-Beran-Bell spaceship paradox and the ‘pole in a barn’ paradox. [Projekat Ministarstva nauke Republike Srbije, br. 171028

  19. USGS Small-scale Dataset - North American Land Cover Characteristics - 1-Kilometer Resolution 200212 GeoTIFF

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This map layer is an Arc/INFO grid map of land cover characteristics for North America, excluding Hawaii, and including the Caribbean and most of Mexico. The...

  20. What does the Romanian workaholic look like? A first glimpse into the links between workaholism and employee characteristics; a validation attempt of DUWAS scale

    OpenAIRE

    Andreea Butucescu; Lavinia C. Uscătescu

    2013-01-01

    The primary objective of this study was to explore the socio-economic and demographic characteristics of the Romanian employee, and see whether these traits might also favor workaholism. In order to do that, a validation of a workaholism assessment tool was necessary. For the purpose of the present study, DUWAS (Dutch Work Addiction Scale) was chosen, as it captures core concepts related to workaholism and is hence widely accepted as a suitable tool. Preliminary results show a suitable valida...