Sample records for characteristic length scale

  1. A Characteristic Particle Length

    CERN Document Server

    Roberts, Mark D


    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.

  2. On determining characteristic length scales in pressure-gradient turbulent boundary layers (United States)

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


    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

  3. Analysis of Voltage Transfer Characteristics of Nano-scale SOI CMOS Inverter with Variable Channel Length and Doping Concentration

    Directory of Open Access Journals (Sweden)

    A. Daniyel Raj


    Full Text Available During many decades, continuous device performance improvement has been made possible only through device scaling. But presently, due to aggressive scaling at the sub-micron or nanometer region, the conventional planner silicon technology is suffering from the fundamental physical limits. Such imposed limits on further downscaling of silicon planner technology have lead to alternative device technology like Silicon-On-Insulator (SOI technology. Due-to some of its inherent advantages, the Silicon-On-Insulator (SOI technology has reduced the Short-channel-effects (SCEs and thus increased transistor scalability. Till now, intense research interests have been paid in practical fabrication and theoretical modeling of SOI MOSFETs but a little attention has been paid to understand the circuit level performance improvement with nano-scale SOI MOSFETs. The circuit level performance analysis of SOI MOSFET is highly essential to understand the impact of SOI technology on next level VLSI circuit and chip design and for doing so device compact models are high on demand. In such scenario, under present research, a physics based compact device model of SOI MOSFET has been developed. At the first phase of the compact model development, a physics based threshold voltage model has been developed by solving 2-D Poisson’s equation at the channel region and at the second phase, a current-voltage model has been developed with drift-diffusion analysis. Different SCEs, valid at nano-scale, are effectively incorporated in threshold voltage and Current-Voltage model. At the third phase, using the compact model, the Voltage Transfer Characteristics (VTC for a nano-scale SOI CMOS inverter has been derived with graphical analysis. The impacts of different device parameters e.g.; channel length and channel doping concentration on VTC has been investigated through simulation and the results have been analyzed.

  4. 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: [Department of Solid State Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)


    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.

  5. PS-b-PEO/Silica Films with Regular and Reverse Mesostructures of Large Characteristic Length Scales Prepared by Solvent Evaporation-Induced Self-Assembly

    Energy Technology Data Exchange (ETDEWEB)



    Since the discovery of surfactant-templated silica by Mobil scientists in 1992, mesostructured silica has been synthesized in various forms including thin films, powders, particles, and fibers. In general, mesostructured silica has potential applications, such as in separation, catalysis, sensors, and fluidic microsystems. In respect to these potential applications, mesostructured silica in the form of thin films is perhaps one of the most promising candidates. The preparation of mesostructured silica films through preferential solvent evaporation-induced self-assembly (EISA) has recently received much attention in the laboratories. However, no amphiphile/silica films with reverse mesophases have ever been made through this EISA procedure. Furthermore, templates employed to date have been either surfactants or poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) triblock copolymers, such as pluronic P-123, both of which are water-soluble and alcohol-soluble. Due to their relatively low molecular weight, the templated silica films with mesoscopic order have been limited to relatively small characteristic length scales. In the present communication, the authors report a novel synthetic method to prepare mesostructured amphiphilic/silica films with regular and reverse mesophases of large characteristic length scales. This method involves evaporation-induced self-assembly (EISA) of amphiphilic polystyrene-block-poly(ethylene oxide) (PS-b-PEO) diblock copolymers. In the present study, the PS-b-PEO diblocks are denoted as, for example, PS(215)-b-PEO(100), showing that this particular sample contains 215 S repeat units and 100 EO repeat units. This PS(215)-b-PEO(100) diblock possesses high molecular weight and does not directly mix with water or alcohol. To the authors knowledge, no studies have reported the use of water-insoluble and alcohol-insoluble amphiphilic diblocks as structure-directing agents in the synthesis of mesostructured silica films through

  6. Minimal Length Scale Scenarios for Quantum Gravity

    Directory of Open Access Journals (Sweden)

    Sabine Hossenfelder


    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.

  7. Hydrodynamic length-scale selection in microswimmer suspensions (United States)

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


    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.

  8. Length-scale dependent phonon interactions

    CERN Document Server

    Srivastava, Gyaneshwar


    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...

  9. Scale Length of the Galactic Thin Disk

    Indian Academy of Sciences (India)

    D. Κ. Ojha


    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).

  10. Length Scale of the Spin Seebeck Effect (United States)

    Kehlberger, Andreas; Ritzmann, Ulrike; Hinzke, Denise; Guo, Er-Jia; Cramer, Joel; Jakob, Gerhard; Onbasli, Mehmet C.; Kim, Dong Hun; Ross, Caroline A.; Jungfleisch, Matthias B.; Hillebrands, Burkard; Nowak, Ulrich; Kläui, Mathias


    We investigate the origin of the spin Seebeck effect in yttrium iron garnet (YIG) samples for film thicknesses from 20 nm to 50 μ m at room temperature and 50 K. Our results reveal a characteristic increase of the longitudinal spin Seebeck effect amplitude with the thickness of the insulating ferrimagnetic YIG, which levels off at a critical thickness that increases with decreasing temperature. The observed behavior cannot be explained as an interface effect or by variations of the material parameters. Comparison to numerical simulations of thermal magnonic spin currents yields qualitative agreement for the thickness dependence resulting from the finite magnon propagation length. This allows us to trace the origin of the observed signals to genuine bulk magnonic spin currents due to the spin Seebeck effect ruling out an interface origin and allowing us to gauge the reach of thermally excited magnons in this system for different temperatures. At low temperature, even quantitative agreement with the simulations is found.

  11. Optimal Length Scale for a Turbulent Dynamo. (United States)

    Sadek, Mira; Alexakis, Alexandros; Fauve, Stephan


    We demonstrate that there is an optimal forcing length scale for low Prandtl number dynamo flows that can significantly reduce the required energy injection rate. The investigation is based on simulations of the induction equation in a periodic box of size 2πL. The flows considered are the laminar and turbulent ABC flows forced at different forcing wave numbers k_{f}, where the turbulent case is simulated using a subgrid turbulence model. At the smallest allowed forcing wave number k_{f}=k_{min}=1/L the laminar critical magnetic Reynolds number Rm_{c}^{lam} is more than an order of magnitude smaller than the turbulent critical magnetic Reynolds number Rm_{c}^{turb} due to the hindering effect of turbulent fluctuations. We show that this hindering effect is almost suppressed when the forcing wave number k_{f} is increased above an optimum wave number k_{f}L≃4 for which Rm_{c}^{turb} is minimum. At this optimal wave number, Rm_{c}^{turb} is smaller by more than a factor of 10 than the case forced in k_{f}=1. This leads to a reduction of the energy injection rate by 3 orders of magnitude when compared to the case where the system is forced at the largest scales and thus provides a new strategy for the design of a fully turbulent experimental dynamo.

  12. Identifying characteristic scales in the human genome (United States)

    Carpena, P.; Bernaola-Galván, P.; Coronado, A. V.; Hackenberg, M.; Oliver, J. L.


    The scale-free, long-range correlations detected in DNA sequences contrast with characteristic lengths of genomic elements, being particularly incompatible with the isochores (long, homogeneous DNA segments). By computing the local behavior of the scaling exponent α of detrended fluctuation analysis (DFA), we discriminate between sequences with and without true scaling, and we find that no single scaling exists in the human genome. Instead, human chromosomes show a common compositional structure with two characteristic scales, the large one corresponding to the isochores and the other to small and medium scale genomic elements.

  13. Characteristic Lengths of Magnetic Field in Magnetohydrodynamic Turbulence

    CERN Document Server

    Cho, Jungyeon


    In the framework of turbulence dynamo, flow motions amplify a weak seed magnetic field through the stretching of field lines. Although the amplification process has been a topic of active research, less attention has been paid to the length scales of magnetic field. In this paper, we described a numerical study on characteristic lengths of magnetic field in magnetohydrodynamic turbulence. We considered the case of very weak or zero mean magnetic field, which is applicable to the turbulence in the intergalactic space. Our findings are as follows. (1) At saturation, the peak of magnetic field spectrum occurs at $\\sim L_0/2$, where $L_0$ is the energy injection scale, while the most energy containing scale is $\\sim L_0/5$. The peak scale of spectrum of projected, two-dimensional field is $\\sim L_0$. (2) During the stage of magnetic field amplification, the energy equipartition scale shows a power-law increase of $\\sim t^{1.5}$, while the integral and curvature scales show a linear increase. The equipartition, in...

  14. Length Scales in Bayesian Automatic Adaptive Quadrature

    Directory of Open Access Journals (Sweden)

    Adam Gh.


    Full Text Available Two conceptual developments in the Bayesian automatic adaptive quadrature approach to the numerical solution of one-dimensional Riemann integrals [Gh. Adam, S. Adam, Springer LNCS 7125, 1–16 (2012] are reported. First, it is shown that the numerical quadrature which avoids the overcomputing and minimizes the hidden floating point loss of precision asks for the consideration of three classes of integration domain lengths endowed with specific quadrature sums: microscopic (trapezoidal rule, mesoscopic (Simpson rule, and macroscopic (quadrature sums of high algebraic degrees of precision. Second, sensitive diagnostic tools for the Bayesian inference on macroscopic ranges, coming from the use of Clenshaw-Curtis quadrature, are derived.

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

    CERN Document Server

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


    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.

  16. Structural and cooperative length scales in polymer gels. (United States)

    Géraud, Baudouin; Jørgensen, Loren; Ybert, Christophe; Delanoë-Ayari, Hélène; Barentin, Catherine


    Understanding the relationship between the material structural details, the geometrical confining constraints, the local dynamical events and the global rheological response is at the core of present investigations on complex fluid properties. In the present article, this problem is addressed on a model yield stress fluid made of highly entangled polymer gels of Carbopol which follows at the macroscopic scale the well-known Herschel-Bulkley rheological law. First, performing local rheology measurements up to high shear rates ([Formula: see text] s(-1))and under confinement, we evidence unambiguously the breakdown of bulk rheology associated with cooperative processes under flow. Moreover, we show that these behaviors are fully captured with a unique cooperativity length [Formula: see text] over the whole range of experimental conditions. Second, we introduce an original optical microscopy method to access structural properties of the entangled polymer gel in the direct space. Performing image correlation spectroscopy of fluorophore-loaded gels, the characteristic size D of carbopol gels microstructure is determined as a function of preparation protocol. Combining both dynamical and structural information shows that the measured cooperative length [Formula: see text] corresponds to 2-5 times the underlying structural size D, thus providing a strong grounding to the "Shear Transformation Zones" modeling approach.

  17. Energy dependent transport length scales in strongly diffusive carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Lassagne, B [Laboratoire National des Champs Magnetiques Pulses, UMR5147 143 avenida de rangueil, 31400 Toulouse (France); Raquet, B [Laboratoire National des Champs Magnetiques Pulses, UMR5147 143 avenida de rangueil, 31400 Toulouse (France); Broto, J M [Laboratoire National des Champs Magnetiques Pulses, UMR5147 143 avenida de rangueil, 31400 Toulouse (France); Gonzalez, J [Centro de Estudios de Semiconductores Facultad de Ciencias, Departamento de Fisica, Universidad de Los Andes, Merida (Venezuela)


    We report magneto-transport measurements in parallel magnetic field and {mu}-Raman spectroscopy on diffusive multiwall carbon nanotubes. The disorder effects on the characteristic transport lengths are probed by combining applied magnetic field and back-gate tuning of the Fermi level. Modulations of the differential conductance versus energy depict the modulation of the strength of the weak localization. Both the electronic mean free path and the phase coherence length are found to be energy dependent. The role of disorder in the density of states and in the characteristic transport lengths is discussed.

  18. Length Scaling of Shear Zones at the Frictional-Viscous Transition (FVT) (United States)

    Schrank, C. E.; Handy, M. R.; Fusseis, F.


    We present a new method for determining the characteristic length scales of strain localization in crustal scale shear zones. This entails determining two parameters that describe the degree of strain heterogeneity in natural shear zones: (1) the strain localization factor, LfRA, defined as the ratio of the shear zone area to a chosen reference area, ARA, and (2) the relative localization intensity, Iloc, a function of the ratio of the mean shear strain to the maximum shear strain measured in a transect of the shear zone. ARA is a geometric homogenization scale determined from autocorrelation functions (ACF) of 2-D images (thin sections, foliation maps and aerial photographs) of shear zone networks on different scales that formed during a single deformational event. When applied to shear zones from a well exposed segment of the frictional-to-viscous transition (FVT) in NE Spain, we found that maxima in LfRA on the mm, cm, m and km scales coincided with the length scales of existing mineralogical and lithological heterogeneities. On any of these characteristic length scales, Iloc increased both along and across the length of the shear zones, suggesting that the shear zones weakening as a function of time and strain. This is consistent with structural evidence for progressive weakening of the crust on the characteristic length scales of strain heterogeneity.

  19. Dynamic length-scale characterization and nonequilibrium statistical mechanics of transport in open-cell foams. (United States)

    Brosten, Tyler R; Codd, Sarah L; Maier, Robert S; Seymour, Joseph D


    Nuclear magnetic resonance measurements of scale dependent dynamics in a random solid open-cell foam reveal a characteristic length scale for transport processes in this novel type of porous medium. These measurements and lattice Boltzmann simulations for a model foam structure indicate dynamical behavior analogous to lower porosity consolidated granular porous media, despite extremely high porosity in solid cellular foams. Scaling by the measured characteristic length collapses data for different foam structures as well as consolidated granular media. The nonequilibrium statistical mechanics theory of preasymptotic dispersion, developed for hierarchical porous media, is shown to model the hydrodynamic dispersive transport in a foam structure.

  20. Introducing artificial length scales to tailor magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Fassbender, J; Strache, T; Liedke, M O; Marko, D; Wintz, S; Lenz, K; Keller, A; Facsko, S [Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf, PO Box 51 01 19, D-01314 Dresden (Germany); Moench, I; McCord, J [Leibniz Institute for Solid State and Materials Research IFW Dresden, PO Box 27 01 16, D-01171 Dresden (Germany)], E-mail:


    Magnetism is a collective phenomenon. Hence, a local variation on the nanoscale of material properties, which act on the magnetic properties, affects the overall magnetism in an intriguing way. Of particular importance are the length scales on which a material property changes. These might be related to the exchange length, the domain wall width, a typical roughness correlation length, or a length scale introduced by patterning of the material. Here we report on the influence of two artificially created length scales: (i) ion erosion templates that serve as a source of a predefined surface morphology (ripple structure) and hence allow for the investigation of roughness phenomena. It is demonstrated that the ripple wave length can be easily tuned over a wide range (25-175 nm) by varying the primary ion erosion energy. The effect of this ripple morphology on the induced uniaxial magnetic anisotropy in soft magnetic Permalloy films is studied. Only below a ripple wavelength threshold ({approx}60 nm) is a significant induced magnetic anisotropy found. Above this threshold the corrugated Permalloy film acts as a flat film. This cross-over is discussed in the frame of dipolar interactions giving rise to the induced anisotropies. (ii) Ion implantation through a lithographically defined mask, which is used for a magnetic property patterning on various length scales. The resulting magnetic properties are neither present in non-implanted nor in homogeneously implanted films. Here new insight is gained by the comparison of different stripe patterning widths ranging from 1 to 10 {mu}m. In addition, the appearance of more complicated magnetic domain structures, i.e. spin-flop domain configurations and head-on domain walls, during hard axis magnetization reversal is demonstrated. In both cases the magnetic properties, the magnetization reversal process as well as the magnetic domain configurations depend sensitively on the artificially introduced length scale.

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

    CERN Document Server

    Berg, Carl Fredrik


    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...

  2. Maximum length scale in density based topology optimization

    DEFF Research Database (Denmark)

    Lazarov, Boyan Stefanov; Wang, Fengwen


    The focus of this work is on two new techniques for imposing maximum length scale in topology optimization. Restrictions on the maximum length scale provide designers with full control over the optimized structure and open possibilities to tailor the optimized design for broader range...... of manufacturing processes by fulfilling the associated technological constraints. One of the proposed methods is based on combination of several filters and builds on top of the classical density filtering which can be viewed as a low pass filter applied to the design parametrization. The main idea...

  3. Length scales in cryogenic injection at supercritical pressure

    Energy Technology Data Exchange (ETDEWEB)

    Branam, R.; Mayer, W. [German Aerospace Center, DLR Lampoldshausen, 74239 Hardthausen (Germany)


    Length scales provide some understanding of the injection of cryogenic propellants in rocket chambers on mixing efficiency, which translates to burning efficiency and performance. This project uses supercritical cryogenic nitrogen to look at high-density core flows such as those of coaxial injectors used in rocket engines. The investigation considers test conditions from 4.0 to 6.0 MPa chamber pressure at two injection velocities and temperatures. Experimental data taken by using shadowgraph images provides a means of characterizing turbulent flow structures using a two-point correlation method to determine length scales and structure shapes. The experimental results are compared to computational models. (orig.)

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

    Institute of Scientific and Technical Information of China (English)

    Jordan Hristov


    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.

  5. Scaling carbon nanotube complementary transistors to 5-nm gate lengths (United States)

    Qiu, Chenguang; Zhang, Zhiyong; Xiao, Mengmeng; Yang, Yingjun; Zhong, Donglai; Peng, Lian-Mao


    High-performance top-gated carbon nanotube field-effect transistors (CNT FETs) with a gate length of 5 nanometers can be fabricated that perform better than silicon complementary metal-oxide semiconductor (CMOS) FETs at the same scale. A scaling trend study revealed that the scaled CNT-based devices, which use graphene contacts, can operate much faster and at much lower supply voltage (0.4 versus 0.7 volts) and with much smaller subthreshold slope (typically 73 millivolts per decade). The 5-nanometer CNT FETs approached the quantum limit of FETs by using only one electron per switching operation. In addition, the contact length of the CNT CMOS devices was also scaled down to 25 nanometers, and a CMOS inverter with a total pitch size of 240 nanometers was also demonstrated.

  6. A two-scale damage model with material length (United States)

    Dascalu, Cristian


    The Note presents the formulation of a class of two-scale damage models involving a micro-structural length. A homogenization method based on asymptotic developments is employed to deduce the macroscopic damage equations. The damage model completely results from energy-based micro-crack propagation laws, without supplementary phenomenological assumptions. We show that the resulting two-scale model has the property of capturing micro-structural lengths. When damage evolves, the micro-structural length is given by the ratio of the surface density of energy dissipated during the micro-crack growth and the macroscopic damage energy release rate per unit volume of the material. The use of fracture criteria based on resistance curves or power laws for sub-critical growth of micro-cracks leads to quasi-brittle and, respectively, time-dependent damage models. To cite this article: C. Dascalu, C. R. Mecanique 337 (2009).

  7. An inertial range length scale in structure functions

    CERN Document Server

    Kerr, R M; Gotoh, T; Kerr, Robert M.; Meneguzzi, Maurice; Gotoh, Toshiyuki


    It is shown using experimental and numerical data that within the traditional inertial subrange defined by where the third order structure function is linear that the higher order structure function scaling exponents for longitudinal and transverse structure functions converge only over larger scales, $r>r_S$, where $r_S$ has scaling intermediate between $\\eta$ and $\\lambda$ as a function of $R_\\lambda$. Below these scales, scaling exponents cannot be determined for any of the structure functions without resorting to procedures such as extended self-similarity (ESS). With ESS, different longitudinal and transverse higher order exponents are obtained that are consistent with earlier results. The relationship of these statistics to derivative and pressure statistics, to turbulent structures and to length scales is discussed.

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

  9. Numerical scalings of the decay lengths in the scrape-off layer

    DEFF Research Database (Denmark)

    Militello, F.; Naulin, V; Nielsen, Anders Henry


    Numerical simulations of L-mode turbulence in the scrape-off layer (SOL) are used to construct power scaling laws for the characteristic decay lengths of the temperature, density and heat flux at the outer mid-plane. Most of the results obtained are in qualitative agreement with the experimental...

  10. Characteristic Scales in Galaxy Formation

    CERN Document Server

    Dekel, A


    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...

  11. 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


    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...

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

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Sanae-I. [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics; Itoh, Kimitaka [National Inst. for Fusion Science, Toki, Gifu (Japan)


    Statistical theory of strong turbulence in inhomogeneous plasmas is extended to the state where fluctuations with different scale lengths, micro and semi-micro modes, coexist. Their nonlinear interactions give several states of turbulence: in one state, the micro mode is excited while the semi-micro mode is quenched; in another state, the latter is excited while the micro mode is suppressed. A new turbulence transition with a hard bifurcation was obtained. A phase diagram was obtained. A new insight is given for the physics of internal transport barrier. (author)

  13. Multi length-scale characterisation inorganic materials series

    CERN Document Server

    Bruce, Duncan W; Walton, Richard I


    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

  14. 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.


    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 ...

  15. Spontaneous transmission of chirality through multiple length scales. (United States)

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


    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

  16. The dynamics of rapid fracture: instabilities, nonlinearities and length scales. (United States)

    Bouchbinder, Eran; Goldman, Tamar; Fineberg, Jay


    The failure of materials and interfaces is mediated by cracks, almost singular dissipative structures that propagate at velocities approaching the speed of sound. Crack initiation and subsequent propagation-the dynamic process of fracture-couples a wide range of time and length scales. Crack dynamics challenge our understanding of the fundamental physics processes that take place in the extreme conditions within the almost singular region where material failure occurs. Here, we first briefly review the classic approach to dynamic fracture, namely linear elastic fracture mechanics (LEFM), and discuss its successes and limitations. We show how, on the one hand, recent experiments performed on straight cracks propagating in soft brittle materials have quantitatively confirmed the predictions of this theory to an unprecedented degree. On the other hand, these experiments show how LEFM breaks down as the singular region at the tip of a crack is approached. This breakdown naturally leads to a new theoretical framework coined 'weakly nonlinear fracture mechanics', where weak elastic nonlinearities are incorporated. The stronger singularity predicted by this theory gives rise to a new and intrinsic length scale, ℓnl. These predictions are verified in detail through direct measurements. We then theoretically and experimentally review how the emergence of ℓnl is linked to a new equation for crack motion, which predicts the existence of a high-speed oscillatory crack instability whose wavelength is determined by ℓnl. We conclude by delineating outstanding challenges in the field.

  17. Characteristic Time Scales of Characteristic Magmatic Processes and Systems (United States)

    Marsh, B. D.


    times comes from the observed durations and rates of volcanism. There can be little doubt that the temporal styles of volcanism are the same as those of magmatism in general. Volcano repose times, periodicity, eruptive fluxes, acoustic emission structures, lava volumes, longevity, etc. must also be characteristic of pluton-dominated systems. We must therefore give up some classical concepts (e.g., instantaneous injection of crystal-free magma as an initial condition) for any plutonic/chambered system and move towards an integrated concept of magmatism. Among the host of process-related time scales, probably the three most fundamental of any magmatic system are (1) the time scale associated with crystal nucleation (J) and growth (G) (tx}=C{1(G3 J)-{1}/4; Zieg & Marsh, J. Pet. 02') along with the associated scales for mean crystal size (L) and population (N), (2) the time scale associated with conductive cooling controlled by a local length scale (d) (tc}=C{2 d2/K; K is thermal diffusivity), and (3) the time scale associated with intra-crystal diffusion (td}=C{3 L2/D; D is chemical diffusivity). It is the subtle, clever, and insightful application of time scales, dovetailed with realistic system geometry and attention paid to the analogous time scales of volcanism, that promises to reveal the true dynamic integration of magmatic systems.

  18. Turbulence and entrainment length scales in large wind farms. (United States)

    Andersen, Søren J; Sørensen, Jens N; Mikkelsen, Robert F


    A number of large wind farms are modelled using large eddy simulations to elucidate the entrainment process. A reference simulation without turbines and three farm simulations with different degrees of imposed atmospheric turbulence are presented. The entrainment process is assessed using proper orthogonal decomposition, which is employed to detect the largest and most energetic coherent turbulent structures. The dominant length scales responsible for the entrainment process are shown to grow further into the wind farm, but to be limited in extent by the streamwise turbine spacing, which could be taken into account when developing farm layouts. The self-organized motion or large coherent structures also yield high correlations between the power productions of consecutive turbines, which can be exploited through dynamic farm control.This article is part of the themed issue 'Wind energy in complex terrains'.

  19. DHS Internship Summary-Crystal Assembly at Different Length Scales

    Energy Technology Data Exchange (ETDEWEB)

    Mishchenko, L


    I was part of a project in which in situ atomic force microscopy (AFM) was used to monitor growth and dissolution of atomic and colloidal crystals. At both length scales, the chemical environment of the system greatly altered crystal growth and dissolution. Calcium phosphate was used as a model system for atomic crystals. A dissolution-reprecipitation reaction was observed in this first system, involving the conversion of brushite (DCPD) to octacalcium phosphate (OCP). In the second system, polymeric colloidal crystals were dissolved in an ionic solvent, revealing the underlying structure of the crystal. The dissolved crystal was then regrown through an evaporative step method. Recently, we have also found that colloids can be reversibly deposited in situ onto an ITO (indium tin oxide) substrate via an electrochemistry setup. The overall goal of this project was to develop an understanding of the mechanisms that control crystallization and order, so that these might be controlled during material synthesis. Controlled assembly of materials over a range of length scales from molecules to nanoparticles to colloids is critical for designing new materials. In particular, developing materials for sensor applications with tailorable properties and long range order is important. In this work, we examine two of these length scales: small molecule crystallization of calcium phosphate (whose crystal phases include DCPD, OCP, and HAP) and colloidal crystallization of Poly(methyl methacrylate) beads. Atomic Force Microscopy is ideal for this line of work because it allows for the possibility of observing non-conducting samples in fluid during growth with high resolution ({approx} 10 nm). In fact, during atomic crystal growth one can observe changes in atomic steps, and with colloidal crystals, one can monitor the individual building blocks of the crystal. Colloids and atoms crystallize under the influence of different forces acting at different length scales as seen in Table 1

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

    CERN Document Server

    Bickel, David R


    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...

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

    Directory of Open Access Journals (Sweden)

    Swapan K. Ghosh


    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.

  2. Fault zone rheology and length scales of frictional failure (United States)

    Fagereng, A.


    Faults have a finite thickness and commonly contain fault rocks of heterogeneous composition, leading to rheological contrasts between intermingled lithologies (at the macroscale) and minerals (at the microscale) within the fault zone. The distribution and volumetric ratio of materials with different viscosity, frictional behavior, and preferred deformation mechanism, may therefore be a critical factor controlling the bulk rheology of heterogeneous fault zones. For example, at subgreenschist facies metamorphic conditions, fine-grained phyllosilicate-dominated mudstones tend to experience viscous shearing flow by dissolution-precipitation creep, whereas coarse grained quartz-dominated sandstones tend to act like competent, brittle volumes. In the rock record, deformation of mixed lithologies is well represented in tectonic mélanges. The subgreenschist facies (P defined by slickenfibre-coated shear surfaces linked by quartz-calcite extension veins. The frequency-size distribution of competent lenses (phacoids) in the Chrystalls Beach Complex follows a power-law distribution and is scale-invariant. The exponent of the power-law distribution varies with dominant deformation style, and is high in zones of dominantly continuous deformation - relating to a high matrix fraction, predominance of small phacoids, and small phacoid aspect ratios, whereas a low power-law exponent relates to a small matrix fraction and localized deformation accommodated on shear discontinuities. This variation in power-law exponent indicates that whether deformation occurs predominantly by continuous or discontinuous deformation may be predicted from the shape of the frequency-size distribution of competent lenses, and supports the hypothesis that bulk rheology is determined by the volume fraction of competent material. The distribution of competent material likely affects the seismic style of actively deforming fault zones. The length scales of shear discontinuities are likely to be a factor

  3. Modelling Time and Length Scales of Scour Around a Pipeline (United States)

    Smith, H. D.; Foster, D. L.


    The scour and burial of submarine objects is an area of interest for engineers, oceanographers and military personnel. Given the limited availability of field observations, there exists a need to accurately describe the hydrodynamics and sediment response around an obstacle using numerical models. In this presentation, we will compare observations of submarine pipeline scour with model predictions. The research presented here uses the computational fluid dynamics (CFD) model FLOW-3D. FLOW-3D, developed by Flow Science in Santa Fe, NM, is a 3-dimensional finite-difference model that solves the Navier-Stokes and continuity equations. Using the Volume of Fluid (VOF) technique, FLOW-3D is able to resolve fluid-fluid and fluid-air interfaces. The FAVOR technique allows for complex geometry to be resolved with rectangular grids. FLOW-3D uses a bulk transport method to describe sediment transport and feedback to the hydrodynamic solver is accomplished by morphology evolution and fluid viscosity due to sediment suspension. Previous investigations by the authors have shown FLOW-3D to well-predict the hydrodynamics around five static scoured bed profiles and a stationary pipeline (``Modelling of Flow Around a Cylinder Over a Scoured Bed,'' submit to Journal of Waterway, Port, Coastal, and Ocean Engineering). Following experiments performed by Mao (1986, Dissertation, Technical University of Denmark), we will be performing model-data comparisons of length and time scales for scour around a pipeline. Preliminary investigations with LES and k-ɛ closure schemes have shown that the model predicts shorter time scales in scour hole development than that observed by Mao. Predicted time and length scales of scour hole development are shown to be a function of turbulence closure scheme, grain size, and hydrodynamic forcing. Subsequent investigations consider variable wave-current flow regimes and object burial. This investigation will allow us to identify different regimes for the

  4. Optically controlled thermal management on the nanometer length scale

    Energy Technology Data Exchange (ETDEWEB)

    Garwe, F [Institute of Photonic Technology (IPHT) Jena, PO Box 100239, D-07745 Jena (Germany); Bauerschaefer, U [GmBU, Erich-Neuss-Weg 5, D-06120 Halle/S (Germany); Csaki, A [Institute of Photonic Technology (IPHT) Jena, PO Box 100239, D-07745 Jena (Germany); Steinbrueck, A [Institute of Photonic Technology (IPHT) Jena, PO Box 100239, D-07745 Jena (Germany); Ritter, K [Technical University Ilmenau, D-98693 Ilmenau (Germany); Bochmann, A [Institute of Photonic Technology (IPHT) Jena, PO Box 100239, D-07745 Jena (Germany); Bergmann, J [Institute of Photonic Technology (IPHT) Jena, PO Box 100239, D-07745 Jena (Germany); Weise, A [Friedrich Schiller University Jena, Institute of Human Genetics and Anthropology, D-07702 Jena (Germany); Akimov, D [Friedrich Schiller University Jena, Institute of Physical Chemistry, D-07743 Jena (Germany); Maubach, G [Institute of Photonic Technology (IPHT) Jena, PO Box 100239, D-07745 Jena (Germany); Koenig, K [Fraunhofer Institut St Ingbert, D-07702 St Ingbert (Germany); Huettmann, G [Medical Laser Center Luebeck, D-23552 Luebeck (Germany); Paa, W [Institute of Photonic Technology (IPHT) Jena, PO Box 100239, D-07745 Jena (Germany); Popp, J [Institute of Photonic Technology (IPHT) Jena, PO Box 100239, D-07745 Jena (Germany); Fritzsche, W [Institute of Photonic Technology (IPHT) Jena, PO Box 100239, D-07745 Jena (Germany)


    The manipulation of polymers and biological molecules or the control of chemical reactions on a nanometer scale by means of laser pulses shows great promise for applications in modern nanotechnology, biotechnology, molecular medicine or chemistry. A controllable, parallel, highly efficient and very local heat conversion of the incident laser light into metal nanoparticles without ablation or fragmentation provides the means for a tool like a 'nanoreactor', a 'nanowelder', a 'nanocrystallizer' or a 'nanodesorber'. In this paper we explain theoretically and show experimentally the interaction of laser radiation with gold nanoparticles on a polymethylmethacrylate (PMMA) layer (one-photon excitation) by means of different laser pulse lengths, wavelengths and pulse repetition rates. To the best of our knowledge this is the first report showing the possibility of highly local (in a 40 nm range) regulated heat insertion into the nanoparticle and its surroundings without ablation of the gold nanoparticles. In an earlier paper we showed that near-infrared femtosecond irradiation can cut labeled DNA sequences in metaphase chromosomes below the diffraction-limited spot size. Now, we use gold as well as silver-enhanced gold nanoparticles on DNA (also within chromosomes) as energy coupling objects for femtosecond laser irradiation with single-and two-photon excitation. We show the results of highly localized destruction effects on DNA that occur only nearby the nanoparticles.

  5. Broadband dielectric microwave microscopy on micron length scales. (United States)

    Tselev, Alexander; Anlage, Steven M; Ma, Zhengkun; Melngailis, John


    We demonstrate that a near-field microwave microscope based on a transmission line resonator allows imaging in a substantially wide range of frequencies, so that the microscope properties approach those of a spatially resolved impedance analyzer. In the case of an electric probe, the broadband imaging can be used in a direct fashion to separate contributions from capacitive and resistive properties of a sample at length scales on the order of one micron. Using a microwave near-field microscope based on a transmission line resonator we imaged the local dielectric properties of a focused ion beam milled structure on a high-dielectric-constant Ba(0.6)Sr(0.4)TiO(3) thin film in the frequency range from 1.3 to 17.4 GHz. The electrostatic approximation breaks down already at frequencies above approximately 10 GHz for the probe geometry used, and a full-wave analysis is necessary to obtain qualitative information from the images.

  6. Model of a fluid at small and large length scales and the hydrophobic effect


    tenWolde, Pieter Rein; Sun, Sean X.; Chandler, David


    We present a statistical field theory to describe large length scale effects induced by solutes in a cold and otherwise placid liquid. The theory divides space into a cubic grid of cells. The side length of each cell is of the order of the bulk correlation length of the bulk liquid. Large length scale states of the cells are specified with an Ising variable. Finer length scale effects are described with a Gaussian field, with mean and variance affected by both the large length scale field and...

  7. Scale factor characteristics of laser gyroscopes of different sizes (United States)

    Fan, Zhenfang; Lu, Guangfeng; Hu, Shomin; Wang, Zhiguo; Luo, Hui


    The scale factor correction characteristics of two ring laser gyroscopes of different sizes are investigated systematically in this paper. The variation in the scale factor can reach 144 or 70 ppm for square gyroscopes with arm lengths of 8.4 cm or 15.6 cm, respectively, during frequency tuning. A dip in the scale factor is observed at the line center of the gain characteristic for both gyroscope sizes. When a different longitudinal mode is excited, the scale factor behavior remains the same, but the scale factor values differ slightly from those derived from geometric prediction. The scale factor tends to decrease with increasing discharge current, but the sensitivity of the scale factor to variations in the excitation decreases with increasing discharge current.

  8. Instantaneous equations for multiphase flow in porous media without length-scale restrictions using a non-local averaging volume

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa-Paredes, Gilberto, E-mail: gepe@xanum.uam.m [Area de Ingenieria en Recursos Energeticos, Universidad Autonoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, Apartado Postal 55-535, Mexico D.F. 09340 (Mexico)


    The aim of this paper is to propose a framework to obtain a new formulation for multiphase flow conservation equations without length-scale restrictions, based on the non-local form of the averaged volume conservation equations. The simplification of the local averaging volume of the conservation equations to obtain practical equations is subject to the following length-scale restrictions: d << l << L, where d is the characteristic length of the dispersed phases, l is the characteristic length of the averaging volume, and L is the characteristic length of the physical system. If the foregoing inequality does not hold, or if the scale of the problem of interest is of the order of l, the averaging technique and therefore, the macroscopic theories of multiphase flow should be modified in order to include appropriate considerations and terms in the corresponding equations. In these cases the local form of the averaged volume conservation equations are not appropriate to describe the multiphase system. As an example of the conservation equations without length-scale restrictions, the natural circulation boiling water reactor was consider to study the non-local effects on the thermal-hydraulic core performance during steady-state and transient behaviors, and the results were compared with the classic local averaging volume conservation equations.

  9. Inlet Turbulence and Length Scale Measurements in a Large Scale Transonic Turbine Cascade (United States)

    Thurman, Douglas; Flegel, Ashlie; Giel, Paul


    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.

  10. The distribution of length scales generated by mixing processes in time-p eriodic chaotic flows (United States)

    Muzzio, Fernando; Alvarez, Mario; Cerbelli, Stefano


    This talk explores in some detail the evolution of the spatial structure and th e statistical properties of partially mixed systems as they evolve on a torus by using a direct numerical simulation of the evolution of continuous material lin es as they are stretched, reoriented, and folded by the flow. In the time scale s of interest to mixing processes, such material lines grow exponentially fast, but much faster than predicted by the Lyapunov exponent. The filament develops into a self-similar structure; frequency distribution of filament densities corr esponding to different times collapses onto an invariant curve by a simple homog eneous scaling. It is shown that this behavior is a direct consequence of a gen eric asymptotic directionality property characteristic of 2D time-periodic flows . Mixture microstructure is also analyzed by computing the evolution of th e distribution of length scales in the flow. Once again, the result is a family of self-similar curves that scale homogeneously by the mean length scale, which collapses in inverse proportion to the rate of growth of the filament. It is s hown that this rate of collapse, which has direct relevance to mixing applicatio ns, can be accurately and straightforwardly predicted from the ergodic average o f the stretching field. Implications for mixing processes in realistic systems are also discussed.

  11. Time and length scales within a fire and implications for numerical simulation

    Energy Technology Data Exchange (ETDEWEB)



    A partial non-dimensionalization of the Navier-Stokes equations is used to obtain order of magnitude estimates of the rate-controlling transport processes in the reacting portion of a fire plume as a function of length scale. Over continuum length scales, buoyant times scales vary as the square root of the length scale; advection time scales vary as the length scale, and diffusion time scales vary as the square of the length scale. Due to the variation with length scale, each process is dominant over a given range. The relationship of buoyancy and baroclinc vorticity generation is highlighted. For numerical simulation, first principles solution for fire problems is not possible with foreseeable computational hardware in the near future. Filtered transport equations with subgrid modeling will be required as two to three decades of length scale are captured by solution of discretized conservation equations. By whatever filtering process one employs, one must have humble expectations for the accuracy obtainable by numerical simulation for practical fire problems that contain important multi-physics/multi-length-scale coupling with up to 10 orders of magnitude in length scale.

  12. Proton conduction in exchange membranes across multiple length scales. (United States)

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


    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

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

    CERN Document Server

    Sprenger, Martin; Bleicher, Marcus


    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...

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

    CERN Document Server

    Voss, Florian; Schmidt, Volker


    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.

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

    DEFF Research Database (Denmark)

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


    of ejaculated sperm that was stored in a queen's spermatheca. Both longer sperm and shorter sperm could be preferentially stored, depending on the colony in which the males and queens were born and raised. These results indicate that the genotype of males may affect sperm length and that cryptic female choice...

  16. Strength-length scaling of elementary hemp fibers (United States)

    Poriķe, E.; Andersons, J.


    The application of hemp fibers as a reinforcement of composite materials necessitates the characterization of fiber strength scatter and the effect of fiber length on its strength. With this aim, elementary hemp fibers were tested in tension at two different gage lengths. Due to the similar morphology of hemp and flax fibers, the probabilistic strength models derived and verified for the latter were applied to the former. The fiber strength was found to agree with the modified Weibull distribution. The modeling approaches developed for describing the variability of the strength and failure strain of elementary flax fibers are shown to be also applicable to hemp fibers.

  17. Determination of length scale effects in nonlocal media

    NARCIS (Netherlands)

    Simone, A; Iacono, C; Sluys, LJ; Yao, ZH; Yuan, MW; Zhong, WX


    A combined continuous-discontinuous framework for failure is presented. Continuous failure is described with a gradient enhanced damage model and discontinuous failure is introduced by adding discontinuities to finite elements through a node-based enhancement. The continuous model contains a length

  18. Characteristic Length of Energy-Containing Structures at the Base of a Coronal Hole

    CERN Document Server

    Abramenko, V I; Dosch, A; Yurchyshyn, V B; Goode, P R; Ahn, K; Cao, W


    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 $\\lambda_{\\bot}$ of the squared velocity and magnetic field fluctuations ($u^2$ and $b^2$) transverse to the mean magnetic field inside a coronal hole (CH) at the base of the corona. The characteristic length scale defines directly 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 (NST) at Big Bear Solar Observatory. A data set for transverse magnetic fields obtained with the Solar Optical Telescope/Spectro-Polarimeter (SOT/SP) aboard {\\it Hinode} spacecraft was utilized to analyze the squared transverse magnetic field fluctuations $b_t^2$. Local correlation tracking (LCT) was applied to derive the squared transverse velocity fluctuations $u^2$. We find that for $u^2$-structures, Batchelor integral scale $\\lambda$ varies in a rang...

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

    CERN Document Server

    Gresnigt, Niels G


    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.

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

    Directory of Open Access Journals (Sweden)

    Guoyong Mao


    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.

  1. Length scales in glass-forming liquids and related systems: a review (United States)

    Karmakar, Smarajit; Dasgupta, Chandan; Sastry, Srikanth


    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.

  2. Reionization: Characteristic Scales, Topology and Observability

    CERN Document Server

    Iliev, Ilian T; Mellema, Garrelt; Pen, Ue-Li; McDonald, Patrick; Alvarez, Marcelo A


    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.

  3. 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


    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.

  4. Filter length scale for continuum modeling of subgrid physics (United States)

    Simeonov, Julian; Calantoni, Joseph


    Modeling the wide range of scales of geophysical processes with direct numerical simulations (DNS) is currently not feasible. It is therefore typical to explicitly resolve only the large energy-containing scales and to parameterize the unresolved small scales. One approach to separate the scales is by means of spatial filters and here we discuss practical considerations regarding the choice of a volume averaging scale L. We use a macroscopically homogeneous scalar field and quantify the smoothness of the filtered field using a noise metric, ν, defined by the standard deviation of the filtered field normalized by the domain-averaged value of the field. For illustration, we consider the continuum modeling of the particle phase in discrete element method (DEM) simulations and the salt fingers in DNS of double-diffusive convection. We find that ν2 follows an inverse power law dependence on L with an exponent and coefficients proportional to the domain-averaged field value. The empirical power law relation can aid in the development of continuum models from fully resolved simulations while also providing uncertainty estimates of the modeled continuum fields.

  5. SQUID magnetometry from nanometer to centimeter length scales

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  6. Length scale of a chaotic element in Rayleigh-Bénard convection. (United States)

    Karimi, A; Paul, M R


    We describe an approach to quantify the length scale of a chaotic element of a Rayleigh-Bénard convection layer exhibiting spatiotemporal chaos. The length scale of a chaotic element is determined by simultaneously evolving the dynamics of two convection layers with a unidirectional coupling that involves only the time-varying values of the fluid velocity and temperature on the lateral boundaries of the domain. In our results we numerically simulate the full Boussinesq equations for the precise conditions of experiment. By varying the size of the boundary used for the coupling we identify a length scale that describes the size of a chaotic element. The length scale of the chaotic element is of the same order of magnitude, and exhibits similar trends, as the natural chaotic length scale that is based upon the fractal dimension.

  7. On scaling performance operating characteristics - Caveat emptor (United States)

    Kantowitz, B. H.; Weldon, M.


    Problems associated with scaling and normalizing empirical performance operating characteristics (POCs) are examined. Normalization methods proposed by Wickens (1980) and by Mountford and North (1980) are critically evaluated. Computer simulations are used to generate raw-score and normalized POCs. The interpretation of transformed empirical POCs (Wickens, Mountford, and Schreiner, 1981) is shown to contain inconsistencies. The normalization techniques reviewed fail to resolve POC scaling problems. Caution must be exercised when interpreting transformed POCs.

  8. Characteristics of donkey spermatozoa along the length of the epididymis. (United States)

    Contri, A; Gloria, A; Robbe, D; De Amicis, I; Carluccio, A


    In mammals, the epididymis has numerous interrelated functions including absorptive and secretory activity that affect luminal environment and cell membrane, and the maturation and storage of sperm. Spermatozoa acquire their motility and fertilizing ability during their passage through the epididymis and the motility of epididymal spermatozoa should be a balance between the maturation of flagellum and the inhibition of the flagellar machinery. In this study maturational change in sperm characteristics were evaluated in the epididymis of donkey. Spermatozoa collected from four portions of the epididymis (head, cranial corpus, caudal corpus, tail) were compared before and after ejaculation for viability, mitochondrial activity, kinetic parameters, and morphology. A significant increase in the mitochondrial activity along the epididymis was reported, suggesting a possible involvement in the motion mechanism. This should be corroborated by the significant correlation between mitochondrial activity and the total and progressive motility and the increase in velocities of spermatozoa recorded by computer-assisted sperm analysis. The percentage of most of the abnormal spermatozoa were similar in all tracts, with a great variability between jackasses. Only the bent midpiece percentage decreased significantly along epididymis. A significant increase in the percentage of distal cytoplasmic droplets (DCD), and a simultaneous decrease in the proximal cytoplasmic droplets (PCD), was found. The DCD fell down after ejaculation suggesting the late loss of the cytoplasmic residual (DCD) in the donkey, as hypothesized in the stallion. Because the prevalence of PCD were similar in both tail epididymal and ejaculated spermatozoa, a defect of the maturative process in the PCD sperm should be speculated.

  9. Nonsymmorphic Phononic Metamaterials: shaping waves over multiple length scales (United States)

    Koh, Cheongyang; Thomas, Edwin


    The vector nature of the phonon makes rational design of phononic metamaterials challenging, despite potential in unique wave propagation behavior, such as negative refraction and hyper-lensing. While most designs to date focus on the ``meta-atom'' (building block) design, their ``spatial arrangement'' (non-locality) is equally instrumental in dispersion engineering. Here, we present a generalized design framework (DF) for PMM design, utilizing both ``global'' and ``local'' symmetry concepts. We demonstrate, utilizing specific properties of nonsymmorphic plane groups, PMMs possessing i) a low-frequency in-plane complete spectral gap (ICSG) of 102% (CSG of 88%), ii) a set of polychromatic ICSGs totaling over 100% in normalized gap size. Within the same DF, we further integrate broken symmetry states (BSS) (edge states, waveguides, etc) with designed polarization, (de)localization and group velocities. In particular, we demonstrate how these BSS may be utilized to elucidate signatures of complex polarization fields through phonon-structure interactions, leading to interesting applications in elastic-wave imaging, as well as information retrieval by probing polarization states of scattering bodies over multiple scales.

  10. Exploring heavy fermions from macroscopic to microscopic length scales (United States)

    Wirth, Steffen; Steglich, Frank


    Strongly correlated systems present fundamental challenges, especially in materials in which electronic correlations cause a strong increase of the effective mass of the charge carriers. Heavy fermion metals — intermetallic compounds of rare earth metals (such as Ce, Sm and Yb) and actinides (such as U, Np and Pu) — are prototype systems for complex and collective quantum states; they exhibit both a lattice Kondo effect and antiferromagnetic correlations. These materials show unexpected phenomena; for example, they display unconventional superconductivity (beyond Bardeen-Cooper-Schrieffer (BCS) theory) and unconventional quantum criticality (beyond the Landau framework). In this Review, we focus on systems in which Landau's Fermi-liquid theory does not apply. Heavy fermion metals and semiconductors are well suited for the study of strong electronic correlations, because the relevant energy scales (for charge carriers, magnetic excitations and lattice dynamics) are well separated from each other, allowing the exploration of concomitant physical phenomena almost independently. Thus, the study of these materials also provides valuable insight for the understanding — and tailoring — of other correlated systems.

  11. Local transport measurements at mesoscopic length scales using scanning tunneling potentiometry. (United States)

    Wang, Weigang; Munakata, Ko; Rozler, Michael; Beasley, Malcolm R


    Under mesoscopic conditions, the transport potential on a thin film carrying a current is theoretically expected to bear spatial variation due to quantum interference. Scanning tunneling potentiometry is the ideal tool to investigate such variation, by virtue of its high spatial resolution. We report in this Letter the first detailed measurement of transport potential under mesoscopic conditions. Epitaxial graphene at a temperature of 17 K was chosen as the initial system for study because the characteristic transport length scales in this material are relatively large. Tip jumping artifacts are a major possible contribution to systematic errors; and we mitigate such problems by using custom-made slender and sharp tips manufactured by focused ion beam. In our data, we observe residual resistivity dipoles associated with topographical defects, and local peaks and dips in the potential that are not associated with topographical defects.

  12. Femtosecond structural dynamics on the atomic length scale

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Dongfang


    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

  13. A linear description of shortening induced changes in isometric length-force characteristics of rat muscle


    Meijer, K; Grootenboer, H.J.; Koopman, H.F.J.M.; Huijing, P.A.


    Active muscle shortening reduces the isometric force potential of muscle. This observation indicates that the isometric length-force characteristics are altered during muscle shortening. Post-shortening decrease in isometric force depends on starting length, shortening amplitude and shortening velocity. In the present study, post-shortening decrease in isometric force was determined after isokinetic contractions with various shortening amplitudes initiated from different lengths of rat medial...

  14. A linear description of shortening induced changes in isometric length-force characteristics of rat muscle

    NARCIS (Netherlands)

    Meijer, K.; Grootenboer, H.J.; Koopman, H.F.J.M.; Huijing, P.A.


    Active muscle shortening reduces the isometric force potential of muscle. This observation indicates that the isometric length-force characteristics are altered during muscle shortening. Post-shortening decrease in isometric force depends on starting length, shortening amplitude and shortening veloc

  15. 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


    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

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

  17. Desert bird associations with broad-scale boundary length: Applications in avian conservation (United States)

    Gutzwiller, K.J.; Barrow, W.C.


    1. Current understanding regarding the effects of boundaries on bird communities has originated largely from studies of forest-non-forest boundaries in mesic systems. To assess whether broad-scale boundary length can affect bird community structure in deserts, and to identify patterns and predictors of species' associations useful in avian conservation, we studied relations between birds and boundary-length variables in Chihuahuan Desert landscapes. Operationally, a boundary was the border between two adjoining land covers, and broad-scale boundary length was the total length of such borders in a large area. 2. Within 2-km radius areas, we measured six boundary-length variables. We analysed bird-boundary relations for 26 species, tested for assemblage-level patterns in species' associations with boundary-length variables, and assessed whether body size, dispersal ability and cowbird-host status were correlates of these associations. 3. The abundances or occurrences of a significant majority of species were associated with boundary-length variables, and similar numbers of species were related positively and negatively to boundary-length variables. 4. Disproportionately small numbers of species were correlated with total boundary length, land-cover boundary length and shrubland-grassland boundary length (variables responsible for large proportions of boundary length). Disproportionately large numbers of species were correlated with roadside boundary length and riparian vegetation-grassland boundary length (variables responsible for small proportions of boundary length). Roadside boundary length was associated (positively and negatively) with the most species. 5. Species' associations with boundary-length variables were not correlated with body size, dispersal ability or cowbird-host status. 6. Synthesis and applications. For the species we studied, conservationists can use the regressions we report as working models to anticipate influences of boundary-length changes

  18. A High-Quality Preconditioning Technique for Multi-Length-Scale Symmetric Positive Definite Linear Systems

    Institute of Scientific and Technical Information of China (English)

    Ichitaro Yamazaki; Zhaojun Bai; Wenbin Chen; Richard Scalettar


    We study preconditioning techniques used in conjunction with the conjugate gradient method for solving multi-length-scale symmetric positive definite linear systems originating from the quantum Monte Carlo simulation of electron interaction of correlated materials. Existing preconditioning techniques are not designed to be adaptive to varying numerical properties of the multi-length-scale systems. In this paper, we propose a hybrid incomplete Cholesky (HIC) preconditioner and demonstrate its adaptivity to the multi-length-scale systems. In addition, we propose an extension of the compressed sparse column with row access (CSCR) sparse matrix storage format to efficiently accommodate the data access pattern to compute the HIC preconditioner. We show that for moderately correlated materials, the HIC preconditioner achieves the optimal linear scaling of the simulation. The development of a linear-scaling preconditioner for strongly correlated materials remains an open topic.

  19. Statistical characteristics of Large Scale Structure


    Demianski; Doroshkevich


    We investigate the mass functions of different elements of the Large Scale Structure -- walls, pancakes, filaments and clouds -- and the impact of transverse motions -- expansion and/or compression -- on their statistical characteristics. Using the Zel'dovich theory of gravitational instability we show that the mass functions of all structure elements are approximately the same and the mass of all elements is found to be concentrated near the corresponding mean mass. At high redshifts, both t...

  20. Variability of interconnected wind plants: correlation length and its dependence on variability time scale (United States)

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


    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

  1. Effect of longwall length on mechanical characteristics of surrounding rock stress shell in mining face

    Energy Technology Data Exchange (ETDEWEB)

    Guang-Xiang Xie; Lei Wang [Anhui University of Science and Technology, Huainan (China)


    The mechanical characteristics of surrounding rock stress shell in longwall mining face were studied, based on the results of in-situ measurement combined with numerical simulation, and the effect of longwall length on mechanical characteristics of surrounding rock stress shell was discovered. The results show that the mechanical characteristics of surrounding rock stress shell are influenced by the length of the face. With an increase of mining face length, the level of concentration of shell stress located in the front face and surrounding rock of roadway is amplified and the three- dimensional stress is focused in the working face. The damage lies in the head entry corner of face and the vertical displacement is reduced but horizontal displacement is enlarged. The dynamic balance of surrounding rock stress shell is improved with rational adjustment of face length. It is effective in protecting the working face and controlling strata behavior. 5 refs., 7 figs.

  2. Empirical scaling of the length of the longest increasing subsequences of random walks (United States)

    Mendonça, J. Ricardo G.


    We provide Monte Carlo estimates of the scaling of the length L n of the longest increasing subsequences of n-step random walks for several different distributions of step lengths, short and heavy-tailed. Our simulations indicate that, barring possible logarithmic corrections, {{L}n}∼ {{n}θ} with the leading scaling exponent 0.60≲ θ ≲ 0.69 for the heavy-tailed distributions of step lengths examined, with values increasing as the distribution becomes more heavy-tailed, and θ ≃ 0.57 for distributions of finite variance, irrespective of the particular distribution. The results are consistent with existing rigorous bounds for θ, although in a somewhat surprising manner. For random walks with step lengths of finite variance, we conjecture that the correct asymptotic behavior of L n is given by \\sqrt{n}\\ln n , and also propose the form for the subleading asymptotics. The distribution of L n was found to follow a simple scaling form with scaling functions that vary with θ. Accordingly, when the step lengths are of finite variance they seem to be universal. The nature of this scaling remains unclear, since we lack a working model, microscopic or hydrodynamic, for the behavior of the length of the longest increasing subsequences of random walks.

  3. A Technique for Mapping Characteristic Lengths to Preserve Energy Dissipated via Strain Softening in a Multiscale Analysis (United States)

    Pineda, Evan J.; Bednarcyk, Brett A.; Arnold, Steven M.


    It is often advantageous to account for the microstructure of the material directly using multiscale modeling. For computational tractability, an idealized repeating unit cell (RUC) is used to capture all of the pertinent features of the microstructure. Typically, the RUC is dimensionless and depends only on the relative volume fractions of the different phases in the material. This works well for non-linear and inelastic behavior exhibiting a positive-definite constitutive response. Although, once the material exhibits strain softening, or localization, a mesh objective failure theories, such as smeared fracture theories, nodal and element enrichment theories (XFEM), cohesive elements or virtual crack closure technique (VCCT), can be utilized at the microscale, but the dimensions of the RUC must then be defined. One major challenge in multiscale progressive damage modeling is relating the characteristic lengths across the scales in order to preserve the energy that is dissipated via localization at the microscale. If there is no effort to relate the size of the macroscale element to the microscale RUC, then the energy that is dissipated will remain mesh dependent at the macroscale, even if it is regularized at the microscale. Here, a technique for mapping characteristic lengths across the scales is proposed. The RUC will be modeled using the generalized method of cells (GMC) micromechanics theory, and local failure in the matrix constituent subcells will be modeled using the crack band theory. The subcell characteristic lengths used in the crack band calculations will be mapped to the macroscale finite element in order to regularize the local energy in a manner consistent with the global length scale. Examples will be provided with and without the regularization, and they will be compared to a baseline case where the size and shape of the element and RUC are coincident (ensuring energy is preserved across the scales).

  4. DNA flexibility on short length scales probed by atomic force microscopy. (United States)

    Mazur, Alexey K; Maaloum, Mounir


    Unusually high bending flexibility has been recently reported for DNA on short length scales. We use atomic force microscopy (AFM) in solution to obtain a direct estimate of DNA bending statistics for scales down to one helical turn. It appears that DNA behaves as a Gaussian chain and is well described by the wormlike chain model at length scales beyond 3 helical turns (10.5 nm). Below this threshold, the AFM data exhibit growing noise because of experimental limitations. This noise may hide small deviations from the Gaussian behavior, but they can hardly be significant.

  5. Factors affecting gestation length and estrus cycle characteristics in Spanish donkey breeds reared in southern Spain. (United States)

    Galisteo, J; Perez-Marin, C C


    This paper investigated gestation length and estrus cycle characteristics in three different Spanish donkey breeds (Andalusian, Zamorano-Leones, and Catalonian) kept on farm conditions in southern Spain, using data for ten consecutive breeding seasons. Gestation length was measured in 58 pregnancies. Ovarian ultrasonography was used to detect the ovulation, in order to ascertain true gestation length (ovulation-parturition). Pregnancy was diagnosed approximately 14-18 d after ovulation and confirmed on approximately day 60. Average gestation length was 362 +/-15.3 (SD) d, and no significant differences were observed between the three different breeds. Breeding season had a significant effect (P gestation length. After parturition, foal-heat was detected in 53.8% of the postpartum cycles studied (n = 78), and ovulation occurred on day 13.2 +/- 2.7. The duration of foal-heat was 4.7 +/-1.7 d, with a pregnancy rate of 40.5%. When subsequent estrus cycles were analyzed, the interovulatory interval (n = 68) and estrus duration (n = 258) were extended to a mean 23.8 +/- 3.5 and 5.7 +/- 2.2 d, respectively. Both variables were influenced by the year of study (P gestation length and estrus cycle characteristics in Spanish jennies. Breeding season affected gestation length in farm conditions. Also, seasonal influence was observed on the length of the estrus cycle (i.e., interovulatory interval), although foal-heat was not affected by environmental factors.

  6. Composition and temperature-induced structural changes in lead-tellurite glasses on different length scales. (United States)

    Chakraborty, S; Arora, A K; Sivasubramanian, V; Krishna, P S R; Krishnan, R Venkata


    Processes occurring at macroscopic and microscopic length scales across the glass transition (T(g)) in lead-tellurite glass (PbO)(x)(TeO(2))(1-x) (x = 0.1-0.3) are investigated using Brillouin and Raman spectroscopy, respectively. For all the samples, the temperature dependence of the longitudinal acoustic (LA) mode is found to exhibit a universal scaling below T(g) and a rapid softening above T(g). The lower value of elastic modulus at a higher concentration of network modifier PbO, estimated from Brillouin data, arises due to loss of network rigidity. From quantitative analysis of the reduced Raman spectra, several modes are found to exhibit anomalous changes across T(g). Instead of the expected anharmonic behaviour, several modes exhibit hardening, suggesting stiffening of the stretching force constants with temperature, the effect being more pronounced in glasses with higher x. In addition, incorporation of PbO in the glass is also found to narrow down the bond-length distribution, as evident from the sharpening of the Raman bands. The stiffening of the force constants of molecular units at a microscopic length scale and the decrease of elastic constant attributed to loss of network rigidity on a macroscopic length scale appear to be opposite. These different behaviours at two length scales are understood on the basis of a microscopic model involving TeO(n) and PbO units in the structure.

  7. An explanation of the relationship between mass, metabolic rate and characteristic length for placental mammals

    Directory of Open Access Journals (Sweden)

    Charles C. Frasier


    Full Text Available The Mass, Metabolism and Length Explanation (MMLE was advanced in 1984 to explain the relationship between metabolic rate and body mass for birds and mammals. This paper reports on a modernized version of MMLE. MMLE deterministically computes the absolute value of Basal Metabolic Rate (BMR and body mass for individual animals. MMLE is thus distinct from other examinations of these topics that use species-averaged data to estimate the parameters in a statistically best fit power law relationship such as BMR = a(bodymassb. Beginning with the proposition that BMR is proportional to the number of mitochondria in an animal, two primary equations are derived that compute BMR and body mass as functions of an individual animal’s characteristic length and sturdiness factor. The characteristic length is a measureable skeletal length associated with an animal’s means of propulsion. The sturdiness factor expresses how sturdy or gracile an animal is. Eight other parameters occur in the equations that vary little among animals in the same phylogenetic group. The present paper modernizes MMLE by explicitly treating Froude and Strouhal dynamic similarity of mammals’ skeletal musculature, revising the treatment of BMR and using new data to estimate numerical values for the parameters that occur in the equations. A mass and length data set with 575 entries from the orders Rodentia, Chiroptera, Artiodactyla, Carnivora, Perissodactyla and Proboscidea is used. A BMR and mass data set with 436 entries from the orders Rodentia, Chiroptera, Artiodactyla and Carnivora is also used. With the estimated parameter values MMLE can calculate characteristic length and sturdiness factor values so that every BMR and mass datum from the BMR and mass data set can be computed exactly. Furthermore MMLE can calculate characteristic length and sturdiness factor values so that every body mass and length datum from the mass and length data set can be computed exactly. Whether or

  8. An explanation of the relationship between mass, metabolic rate and characteristic length for placental mammals (United States)


    The Mass, Metabolism and Length Explanation (MMLE) was advanced in 1984 to explain the relationship between metabolic rate and body mass for birds and mammals. This paper reports on a modernized version of MMLE. MMLE deterministically computes the absolute value of Basal Metabolic Rate (BMR) and body mass for individual animals. MMLE is thus distinct from other examinations of these topics that use species-averaged data to estimate the parameters in a statistically best fit power law relationship such as BMR = a(bodymass)b. Beginning with the proposition that BMR is proportional to the number of mitochondria in an animal, two primary equations are derived that compute BMR and body mass as functions of an individual animal’s characteristic length and sturdiness factor. The characteristic length is a measureable skeletal length associated with an animal’s means of propulsion. The sturdiness factor expresses how sturdy or gracile an animal is. Eight other parameters occur in the equations that vary little among animals in the same phylogenetic group. The present paper modernizes MMLE by explicitly treating Froude and Strouhal dynamic similarity of mammals’ skeletal musculature, revising the treatment of BMR and using new data to estimate numerical values for the parameters that occur in the equations. A mass and length data set with 575 entries from the orders Rodentia, Chiroptera, Artiodactyla, Carnivora, Perissodactyla and Proboscidea is used. A BMR and mass data set with 436 entries from the orders Rodentia, Chiroptera, Artiodactyla and Carnivora is also used. With the estimated parameter values MMLE can calculate characteristic length and sturdiness factor values so that every BMR and mass datum from the BMR and mass data set can be computed exactly. Furthermore MMLE can calculate characteristic length and sturdiness factor values so that every body mass and length datum from the mass and length data set can be computed exactly. Whether or not MMLE can

  9. Dynamics and correlation length scales of a glass-forming liquid in quiescent and sheared conditions (United States)

    Xu, Wen-Sheng; Sun, Zhao-Yan; An, Li-Jia


    We numerically study dynamics and correlation length scales of a colloidal liquid in both quiescent and sheared conditions to further understand the origin of slow dynamics and dynamic heterogeneity in glass-forming systems. The simulation is performed in a weakly frustrated two-dimensional liquid, where locally preferred order is allowed to develop with increasing density. The four-point density correlations and bond-orientation correlations, which have been frequently used to capture dynamic and static length scales ξ in a quiescent condition, can be readily extended to a system under steady shear in this case. In the absence of shear, we confirmed the previous findings that the dynamic slowing down accompanies the development of dynamic heterogeneity. The dynamic and static length scales increase with α-relaxation time τα as a power law \\xi \\sim {\\tau }_{\\alpha }^{\\mu }, with μ > 0. In the presence of shear, both viscosity and τα have power-law dependences on shear rate in the marked shear-thinning regime. However, the dependence of correlation lengths cannot be described by power laws in the same regime. Furthermore, the relation \\xi \\sim {\\tau }_{\\alpha }^{\\mu } between length scales and dynamics holds for not too strong shear where thermal fluctuations and external forces are both important in determining the properties of dense liquids. Thus, our results demonstrate a link between slow dynamics and structure in glass-forming liquids even under nonequilibrium conditions.

  10. A Characteristic Scale for Cold Gas

    CERN Document Server

    McCourt, Michael; O'Leary, Ryan M; Madigan, Ann-Marie


    We find that clouds of optically-thin, pressure-confined gas are prone to fragmentation as they cool below $\\sim10^6$ K. This fragmentation follows the lengthscale $\\sim{c}_{\\text{s}}\\,t_{\\text{cool}}$, ultimately reaching very small scales ($\\sim{0.1} \\text{pc}/n$) as they reach the temperature $\\sim10^4$ K at which hydrogen recombines. While this lengthscale depends on the ambient pressure confining the clouds, we find that the column density through an individual fragment $N_{\\text{cloudlet}}\\sim10^{17} \\text{cm}^{-3}$ is essentially independent of environment; this column density represents a characteristic scale for atomic gas at $10^4$ K. We therefore suggest that "clouds" of cold, atomic gas may in fact have the structure of a mist or a fog, composed of tiny fragments dispersed throughout the ambient medium. We show that this scale emerges in hydrodynamic simulations, and that the corresponding increase in the surface area may imply rapid entrainment of cold gas. We also apply it to a number of observa...

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

    Indian Academy of Sciences (India)

    Biman Bagchi; Charusita Chakravarty


    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.

  12. Scale and construal: how larger measurement units shrink length estimates and expand mental horizons. (United States)

    Maglio, Sam J; Trope, Yaacov


    Scale can vary by requiring a different number of units to measure the same target. But what are the consequences of using fewer, larger units? We draw on past psychophysical research that shows how using fewer units reduces clutter in measurement, translating to shorter length estimates. Additionally, we propose that larger scale is associated with targets further from a person's immediate experience (i.e., psychologically distant) and higher order mental representation. Evidence from Study 1 indicates that framing a target as further away causes it to be estimated as shorter because people use larger units to measure it compared to when the same target is framed as nearby. Two subsequent studies suggest that direct manipulation of larger (versus smaller) measurement scale produces not only shorter length estimates, but also more distal timing judgments (Study 2) and abstract mental representation (Study 3). Implications for scale and level of mental construal are discussed.

  13. What structural length scales can be detected by the spectral variance of a microscope image?


    Cherkezyan, Lusik; Subramanian, Hariharan; Backman, Vadim


    A spectroscopic microscope, configured to detect interference spectra of backscattered light in the far zone, quantifies the statistics of refractive-index (RI) distribution via the spectral variance (Σ̃2) of the acquired bright-field image. Its sensitivity to subtle structural changes within weakly scattering, label-free media at subdiffraction scales shows great promise in fields from material science to medical diagnostics. We further investigate the length-scale sensitivity of Σ̃ and reve...

  14. Effects of chop length and ensiling period of forage maize on in vitro rumen fermentation characteristics

    NARCIS (Netherlands)

    Cone, J.W.; Gelder, van A.H.; Schooten, van H.A.


    The effect of chop length and ensiling period on in vitro rumen fermentation characteristics of forage maize was studied in two experiments. In the first experiment, maize plants of eight cultivars representing different combinations of Dry Down, Stay Green, early ripening, late ripening, starch and

  15. Characteristics of echolocating bats’auditory stereocilia length, compared with other mammals

    Institute of Scientific and Technical Information of China (English)


    The stereocilia of the Organ of Corti in 4 different echolocating bats, Myotis adversus, Murina leuco-gaster, Nyctalus plancyi (Nyctalus velutinus), and Rhinolophus ferrumequinum were observed by using scanning electron microscopy (SEM). Stereocilia lengths were estimated for comparison with those of non-echolocating mammals. The specialized lengths of outer hair cells (OHC) stereocilia in echolocating bats were shorter than those of non-echolocating mammals. The specialized lengths of inner hair cells (IHC) stereocilia were longer than those of outer hair cells stereocilia in the Organ of Corti of echolocating bats. These characteristics of the auditory stereocilia length of echolocating bats represent the fine architecture of the electromotility process, helping to adapt to high frequency sound and echolocation.

  16. Characteristics of echolocating bats' auditory stereocilia length, compared with other mammals

    Institute of Scientific and Technical Information of China (English)

    YAO Qian; ZENG JinYao; ZHENG YongMei; Julia LATHAM; LIANG Bing; JIANG Lei; ZHANG ShuYi


    The stereocilia of the Organ of Corti in 4 different echolocating bats, Myotis adversus, Murina leucogaster, Nyctalus plancyi (Nyctalus velutinus), and Rhinolophus ferrumequinum were observed by using scanning electron microscopy (SEM). Stereocilia lengths were estimated for comparison with those of non-echolocating mammals. The specialized lengths of outer hair cells (OHC) stereocilia in echolocating bats were shorter than those of non-echolocating mammals. The specialized lengths of inner hair cells (IHC) stereocilia were longer than those of outer hair cells stereocilia in the Organ of Corti of echolocating bats. These characteristics of the auditory stereocilia length of echolocating bats represent the fine architecture of the electromotility process, helping to adapt to high frequency sound and echolocation.

  17. Integral Length and Time Scales of Velocity, Heat and Mass At and Near a Turbulent Free Surface (United States)

    Curtis, G. M.; Zappa, C. J.; Variano, E. A.


    variation in integral length scales enabled the effective identification of periods of heavy turbulent mixing at the surface and revealed the localized nature of such events. Analogous to the integral length scale, the integral time scale analysis revealed the characteristic duration of turbulent events at the surface. Covariance and cospectra quantify the time and length scales that are most relevant to fluxes. The measurements presented here will increase our understanding of turbulent transport across the air-sea interface.

  18. Clinicopathological characteristics of TERT promoter mutation and telomere length in hepatocellular carcinoma (United States)

    Lee, Hye Won; Park, Tae In; Jang, Se Young; Park, Soo Young; Park, Won-Jin; Jung, Soo-Jung; Lee, Jae-Ho


    Abstract Promoter mutations in telomerase reverse transcriptase (TERT) and telomere length have been studied in various tumors. In the present study, the frequency and clinical characteristics of TERT promoter mutation and telomere length were studied in hepatocellular carcinoma (HCC). TERT promoter mutation and telomere length were analyzed in 162 tumor samples of the patients with HCC by sequencing and real-time PCR, respectively. The TERT promoter mutation rate was 28.8% (46/160) in HCC and was associated with males (P = 0.027). The telomere length was not significantly different in the presence of a TERT promoter mutation but was shorter in high-grade tumor stages (P = 0.048). Survival analyses showed that poor overall survival was associated with longer telomere length (P = 0.013). However, the TERT promoter mutation did not have a prognostic value for HCC. Multivariate survival analyses demonstrated that the telomere length was an independent prognostic marker for poor overall survival (hazard ratio = 1.75, 95% confidence interval: 1.046–2.913, P = 0.033). These data demonstrated that TERT promoter mutation is a frequent event in HCC; however, telomere length, but not the presence of a TERT promoter mutation, might have potential value as a prognostic indicator of HCC. PMID:28151853

  19. Clinicopathological characteristics of TERT promoter mutation and telomere length in hepatocellular carcinoma. (United States)

    Lee, Hye Won; Park, Tae In; Jang, Se Young; Park, Soo Young; Park, Won-Jin; Jung, Soo-Jung; Lee, Jae-Ho


    Promoter mutations in telomerase reverse transcriptase (TERT) and telomere length have been studied in various tumors. In the present study, the frequency and clinical characteristics of TERT promoter mutation and telomere length were studied in hepatocellular carcinoma (HCC). TERT promoter mutation and telomere length were analyzed in 162 tumor samples of the patients with HCC by sequencing and real-time PCR, respectively. The TERT promoter mutation rate was 28.8% (46/160) in HCC and was associated with males (P = 0.027). The telomere length was not significantly different in the presence of a TERT promoter mutation but was shorter in high-grade tumor stages (P = 0.048). Survival analyses showed that poor overall survival was associated with longer telomere length (P = 0.013). However, the TERT promoter mutation did not have a prognostic value for HCC. Multivariate survival analyses demonstrated that the telomere length was an independent prognostic marker for poor overall survival (hazard ratio = 1.75, 95% confidence interval: 1.046-2.913, P = 0.033). These data demonstrated that TERT promoter mutation is a frequent event in HCC; however, telomere length, but not the presence of a TERT promoter mutation, might have potential value as a prognostic indicator of HCC.

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

    CERN Document Server

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


    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.

  1. Nano-scaled graphene platelets with a high length-to-width aspect ratio (United States)

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


    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.

  2. Microstructural features of composite whey protein/polysaccharide gels characterized at different length scales

    NARCIS (Netherlands)

    Berg, van den L.; Rosenberg, Y.; Boekel, van M.A.J.S.; Rosenberg, M.; Velde, van de F.


    Mixed biopolymer gels are often used to model semi-solid food products. Understanding of their functional properties requires knowledge about structural elements composing these systems at various length scales. This study has been focused on investigating the structural features of mixed cold-set g

  3. Enhanced Strain in Functional Nanoporous Gold with a Dual Microscopic Length Scale Structure

    NARCIS (Netherlands)

    Detsi, Eric; Punzhin, Sergey; Rao, Jiancun; Onck, Patrick R.; De Hosson, Jeff Th. M.


    We have synthesized nanoporous Au with a dual microscopic length scale by exploiting the crystal structure of the alloy precursor. The synthesized mesoscopic material is characterized by stacked Au layers of submicrometer thickness. In addition, each layer displays nanoporosity through the entire bu

  4. Microphase separation in multiblock copolymer melts : Nonconventional morphologies and two-length-scale switching

    NARCIS (Netherlands)

    Smirnova, YG; ten Brinke, G; Erukhimovich, IY; Smirnova, Yuliya G.; Erukhimovich, Igor Ya.


    The phase behavior of A(fmN)(B(N/2)A(N/2))B(1-f)mN multiblock copolymer melts is studied within the weak segregation theory. The interplay between ordering on different length scales is shown to cause dramatic changes both in the ordered phase symmetry and periodicity upon small variation of the arc

  5. Roughness controlled superhydrophobicity on single nanometer length scale with metal nanoparticles

    NARCIS (Netherlands)

    ten Brink, Gert H.; Foley, Nolan; Zwaan, Darin; Kooi, Bart J.; Palasantzas, Georgios


    Here we demonstrate high water pinning nanostructures and trapping of water droplets onto surfaces via control of roughness on a single nanometer length-scale generated by deposition of preformed gas phase distinct copper nanoparticles on hydrophilic and hydrophobic surfaces. It was found that the c

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

    DEFF Research Database (Denmark)

    Johansson, Jens; Christensen, Silas Sverre


    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...

  7. A multiple length scale description of the mechanism of elastomer stretching

    DEFF Research Database (Denmark)

    Neuefeind, J.; Skov, Anne Ladegaard; Daniels, J. E.;


    Conventionally, the stretching of rubber is modeled exclusively by rotations of segments of the embedded polymer chains; i.e. changes in entropy. However models have not been tested on all relevant length scales due to a lack of appropriate probes. Here we present a universal X-ray based method...

  8. Length-scale mediated adhesion and directed growth of neural cells by surface-patterned poly(ethylene glycol) hydrogels. (United States)

    Krsko, Peter; McCann, Thomas E; Thach, Thu-Trang; Laabs, Tracy L; Geller, Herbert M; Libera, Matthew R


    We engineered surfaces that permit the adhesion and directed growth of neuronal cell processes but that prevent the adhesion of astrocytes. This effect was achieved based on the spatial distribution of sub-micron-sized cell-repulsive poly(ethylene glycol) [PEG] hydrogels patterned on an otherwise cell-adhesive substrate. Patterns were identified that promoted cellular responses ranging from complete non-attachment, selective attachment, and directed growth at both cellular and subcellular length scales. At the highest patterning density where the individual hydrogels almost overlapped, there was no cellular adhesion. As the spacing between individual hydrogels was increased, patterns were identified where neurites could grow on the adhesive surface between hydrogels while astrocytes were unable to adhere. Patterns such as lines or arrays were identified that could direct the growth of these subcellular neuronal processes. At higher hydrogel spacings, both neurons and astrocytes adhered and grew in a manner approaching that of unpatterned control surfaces. Patterned lines could once again direct growth at cellular length scales. Significantly, we have demonstrated that the patterning of sub-micron/nano scale cell-repulsive features at microscale lengths on an otherwise cell-adhesive surface can differently control the adhesion and growth of cells and cell processes based on the difference in their characteristic sizes. This concept could potentially be applied to an implantable nerve-guidance device that would selectively enable regrowing axons to bridge a spinal-cord injury without interference from the glial scar.

  9. Scale and time dependence of serial correlations in word-length time series of written texts (United States)

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


    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.

  10. Neighborhood characteristics and leukocyte telomere length: the Multi-Ethnic Study of Atherosclerosis. (United States)

    Needham, Belinda L; Carroll, Judith E; Diez Roux, Ana V; Fitzpatrick, Annette L; Moore, Kari; Seeman, Teresa E


    Telomeres are the protective caps at the ends of eukaryotic chromosomes. Telomeres get shorter each time a cell divides, and critically shortened telomeres trigger cellular senescence. Thus, telomere length is hypothesized to be a biological marker of aging. The purpose of this study was to examine the association between neighborhood characteristics and leukocyte telomere length. Using data from a subsample (n=978) of the Multi-Ethnic Study of Atherosclerosis, a population-based study of women and men aged 45-84, we found that neighborhood social environment (but not neighborhood socioeconomic disadvantage) was associated with telomere length. Respondents who lived in neighborhoods characterized by lower aesthetic quality, safety, and social cohesion had shorter telomeres than those who lived in neighborhoods with a more salutary social environment, even after adjusting for individual-level socioeconomic status and biomedical and lifestyle factors related to telomere length. Telomere length may be one biological mechanism by which neighborhood characteristics influence an individual׳s risk of disease and death.

  11. An actuator line model simulation with optimal body force projection length scales (United States)

    Martinez-Tossas, Luis; Churchfield, Matthew J.; Meneveau, Charles


    In recent work (Martínez-Tossas et al. "Optimal smoothing length scale for actuator line models of wind turbine blades", preprint), an optimal body force projection length-scale for an actuator line model has been obtained. This optimization is based on 2-D aerodynamics and is done by comparing an analytical solution of inviscid linearized flow over a Gaussian body force to the potential flow solution of flow over a Joukowski airfoil. The optimization provides a non-dimensional optimal scale ɛ / c for different Joukowski airfoils, where ɛ is the width of the Gaussian kernel and c is the chord. A Gaussian kernel with different widths in the chord and thickness directions can further reduce the error. The 2-D theory developed is extended by simulating a full scale rotor using the optimal body force projection length scales. Using these values, the tip losses are captured by the LES and thus, no additional explicit tip-loss correction is needed for the actuator line model. The simulation with the optimal values provides excellent agreement with Blade Element Momentum Theory. This research is supported by the National Science Foundation (Grant OISE-1243482, the WINDINSPIRE project).

  12. Length Scale of Free Stream Turbulence and Its Impact on Bypass Transition in a Boundary Layer

    Directory of Open Access Journals (Sweden)

    J. Grzelak


    Full Text Available An experimental investigation was carried out to study the turbulent flow over a flat plate in a subsonic wind tunnel. The enhanced level of turbulence was generated by five wicker grids with square meshes, and different parameters (diameter of the grid rod d = 0.3 to 3 mm and the grid mesh size M = 1 to 30 mm. The velocity of the flow was measured by means of a 1D hot-wire probe, suitable for measurements in a boundary layer. The main aim of the investigation was to explore the influence of the free stream turbulence length scale on the onset of laminar-turbulent bypass transition in a boundary layer on a flat plate. For this purpose, several transition correlations were presented, including intensity and length scales of turbulence, both at the leading edge of a plate and at the onset of transition. The paper ends with an attempt to create a correlation, which takes into account a simultaneous impact of turbulence intensity and turbulence scale on the boundary layer transition. To assess the isotropy of turbulence, the skewness factor of the flow velocity distribution was determined. Also several longitudinal scales of turbulence were determined and compared (integral scale, dissipation scale, Taylor microscale and Kolmogorov scale for different grids and different velocities of the mean flow U = 4, 6, 10, 15, 20 m/s.

  13. Frequency-wavenumber velocity spectra, Taylor's hypothesis, and length scales in a natural gravel bed river (United States)

    Macmahan, Jamie; Reniers, Ad; Ashley, Will; Thornton, Ed


    Macroscale turbulent coherent flow structures in a natural fast-flowing river were examined with a combination of a novel 2 MHz Acoustic Doppler Beam (ADB) and a Maximum Likelihood Estimator (MLE) to characterize the streamwise horizontal length scales and persistence of coherent flow structures by measuring the frequency (f)-streamwise-wavenumber (ks) energy density velocity spectrum, E(f, ks), for the first time in natural rivers. The ADB was deployed under a range of Froude numbers (0.1-0.6) at high Reynolds numbers (˜106) based on depth and velocity conditions within a gravel bed reach of the Kootenai River, Idaho. The MLE employed on the ADB data increased our ability to describe river motions with relatively long (>10 m) length scales in ˜1 m water depths. The E(f, ks) spectra fell along a ridge described by V = f/ks, where Vis the mean velocity over depth, consistent with Taylor's hypothesis. New, consistent length scale measures are defined based on averaged wavelengths of the low-frequencyE(f, ks) and coherence spectra. Energetic (˜50% of the total spectral energy), low-frequency (f 1 m/s,Lmwere found to be significantly longer than their corresponding coherence lengths, suggesting that the turbulent structures evolve rapidly under these conditions. This is attributed to the stretching and concomitant deformation of preexisting macroturbulent motions by the ubiquitous bathymetry-induced spatial flow accelerations present in a natural gravel bed river.

  14. 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


    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.

  15. An Imaging System for Automated Characteristic Length Measurement of Debrisat Fragments (United States)

    Moraguez, Mathew; Patankar, Kunal; Fitz-Coy, Norman; Liou, J.-C.; Sorge, Marlon; Cowardin, Heather; Opiela, John; Krisko, Paula H.


    The debris fragments generated by DebriSat's hypervelocity impact test are currently being processed and characterized through an effort of NASA and USAF. The debris characteristics will be used to update satellite breakup models. In particular, the physical dimensions of the debris fragments must be measured to provide characteristic lengths for use in these models. Calipers and commercial 3D scanners were considered as measurement options, but an automated imaging system was ultimately developed to measure debris fragments. By automating the entire process, the measurement results are made repeatable and the human factor associated with calipers and 3D scanning is eliminated. Unlike using calipers to measure, the imaging system obtains non-contact measurements to avoid damaging delicate fragments. Furthermore, this fully automated measurement system minimizes fragment handling, which reduces the potential for fragment damage during the characterization process. In addition, the imaging system reduces the time required to determine the characteristic length of the debris fragment. In this way, the imaging system can measure the tens of thousands of DebriSat fragments at a rate of about six minutes per fragment, compared to hours per fragment in NASA's current 3D scanning measurement approach. The imaging system utilizes a space carving algorithm to generate a 3D point cloud of the article being measured and a custom developed algorithm then extracts the characteristic length from the point cloud. This paper describes the measurement process, results, challenges, and future work of the imaging system used for automated characteristic length measurement of DebriSat fragments.

  16. Wall-modeled large eddy simulation of turbulent channel flow at high Reynolds number using the von Karman length scale (United States)

    Xu, Jinglei; Li, Meng; Zhang, Yang; Chen, Longfei


    The von Karman length scale is able to reflect the size of the local turbulence structure. However, it is not suitable for the near wall region of wall-bounded flows, for its value is almost infinite there. In the present study, a simple and novel length scale combining the wall distance and the von Karman length scale is proposed by introducing a structural function. The new length scale becomes the von Karman length scale once local unsteady structures are detected. The proposed method is adopted in a series of turbulent channel flows at different Reynolds numbers. The results show that the proposed length scale with the structural function can precisely simulate turbulence at high Reynolds numbers, even with a coarse grid resolution.

  17. Scaling analysis of random walks with persistence lengths: Application to self-avoiding walks (United States)

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


    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.

  18. Measurements of the Influence of Integral Length Scale on Stagnation Region Heat Transfer (United States)

    Vanfossen, G. James; Ching, Chang Y.


    The purpose was twofold: first, to determine if a length scale existed that would cause the greatest augmentation in stagnation region heat transfer for a given turbulence intensity and second, to develop a prediction tool for stagnation heat transfer in the presence of free stream turbulence. Toward this end, a model with a circular leading edge was fabricated with heat transfer gages in the stagnation region. The model was qualified in a low turbulence wind tunnel by comparing measurements with Frossling's solution for stagnation region heat transfer in a laminar free stream. Five turbulence generating grids were fabricated; four were square mesh, biplane grids made from square bars. Each had identical mesh to bar width ratio but different bar widths. The fifth grid was an array of fine parallel wires that were perpendicular to the axis of the cylindrical leading edge. Turbulence intensity and integral length scale were measured as a function of distance from the grids. Stagnation region heat transfer was measured at various distances downstream of each grid. Data were taken at cylinder Reynolds numbers ranging from 42,000 to 193,000. Turbulence intensities were in the range 1.1 to 15.9 percent while the ratio of integral length scale to cylinder diameter ranged from 0.05 to 0.30. Stagnation region heat transfer augmentation increased with decreasing length scale. An optimum scale was not found. A correlation was developed that fit heat transfer data for the square bar grids to within +4 percent. The data from the array of wires were not predicted by the correlation; augmentation was higher for this case indicating that the degree of isotropy in the turbulent flow field has a large effect on stagnation heat transfer. The data of other researchers are also compared with the correlation.

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

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Dohyun; Lee, Jaehyeong; Choi, Byoungdeog, E-mail:


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

    Institute of Scientific and Technical Information of China (English)

    MUTOH; Yoshiharu


    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.

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

  2. Effects of chop length and ensiling period of forage maize on in vitro rumen fermentation characteristics


    Cone, J.W.; Gelder, De; Schooten, van, H.A.


    The effect of chop length and ensiling period on in vitro rumen fermentation characteristics of forage maize was studied in two experiments. In the first experiment, maize plants of eight cultivars representing different combinations of Dry Down, Stay Green, early ripening, late ripening, starch and cell wall types were chopped at harvest into pieces of 6 or 15 mm and ensiled in small laboratory silos. After 8 weeks, silage samples were taken and freeze-dried (not ground) before in vitro rume...

  3. Length Scales of Magmatic Segments at Intermediate and Fast Spreading Ridges (United States)

    Boulahanis, B.; Carbotte, S. M.; Klein, E. M.; Smith, D. K.; Cannat, M.


    A synthesis of observations from fast and magmatically-robust intermediate spreading ridges suggest that fine-scale tectonic segments, previously classified as 3rd order, correspond with principle magmatic segments along these ridges, each with their own magmatic plumbing system in the crust and shallow mantle. In this study, we use multi-beam sonar data available for fast and intermediate spreading ridges to determine the length distribution of these segments for comparison with the primary segmentation of the ridge axis found at slower spreading ridges. A study of intermediate, slow and ultraslow-spreading ridges using global satellite-derived bathymetry indicates a dominant segment length of 53 km [Briais and Rabinowicz, J. Geophys. Res. 2002]. However, satellite-derived bathymetry cannot be used to identify fine-scale tectonic segmentation of fast and magmatically-robust intermediate spreading ridges due to the subdued low-relief expression of ridge-axis discontinuities along these spreading rates. This study focuses on the well-mapped regions of the East Pacific Rise between 13.35°S and 18°N, and the Galapagos Spreading Center between 85° and 95.38° W. We reexamine tectonic segmentation of the ridge axis previously identified in the literature and modify the locations of ridge-axis discontinuities defining segment ends in regions where modern multi-beam bathymetric data coverage has improved relative to that available in early studies. Discontinuities of first, second, and third order are used to define tectonic segment lengths. Initial results show a mean segment length of 42 km (standard deviation of 27 km) and a median of 33 km, with 85 segments studied, similar to the segment length distributions observed at slower spreading ridges. To further evaluate the hypothesis of principle magmatic segments, we also examine the relationship between fine-scale tectonic segmentation and properties of the crustal magmatic system imaged in prior seismic studies of

  4. A mass-length scaling law for modeling muscle strength in the lower limb. (United States)

    Correa, Tomas A; Pandy, Marcus G


    Musculoskeletal computer models are often used to study muscle function in children with and without impaired mobility. Calculations of muscle forces depend in part on the assumed strength of each muscle, represented by the peak isometric force parameter, which is usually based on measurements obtained from cadavers of adult donors. The aim of the present study was twofold: first, to develop a method for scaling lower-limb peak isometric muscle forces in typically-developing children; and second, to determine the effect of this scaling method on model calculations of muscle forces obtained for normal gait. Muscle volumes were determined from magnetic resonance (MR) images obtained from ten children aged from 7 to 13yr. A new mass-length scaling law was developed based on the assumption that muscle volume and body mass are linearly related, which was confirmed by the obtained volume and body mass data. Two musculoskeletal models were developed for each subject: one in which peak isometric muscle forces were estimated using the mass-length scaling law; and another in which these parameters were determined directly from the MR-derived muscle volumes. Musculoskeletal modeling and quantitative gait analysis were then used to calculate lower-limb muscle forces in normal walking. The patterns of muscle forces predicted by the model with scaled peak isometric force values were similar to those predicted by the MR-based model, implying that assessments of muscle function obtained from these two methods are practically equivalent. These results support the use of mass-length scaling in the development of subject-specific musculoskeletal models of children.

  5. 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: [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: [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)


    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.

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


    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.

  7. Characterizing tumor response to chemotherapy at various length scales using temporal diffusion spectroscopy.

    Directory of Open Access Journals (Sweden)

    Junzhong Xu

    Full Text Available Measurements of apparent diffusion coefficient (ADC using magnetic resonance imaging (MRI have been suggested as potential imaging biomarkers for monitoring tumor response to treatment. However, conventional pulsed-gradient spin echo (PGSE methods incorporate relatively long diffusion times, and are usually sensitive to changes in cell density and necrosis. Diffusion temporal spectroscopy using the oscillating gradient spin echo (OGSE sequence is capable of probing short length scales, and may detect significant intracellular microstructural changes independent of gross cell density changes following anti-cancer treatment. To test this hypothesis, SW620 xenografts were treated by barasertib (AZD1152, a selective inhibitor of Aurora B kinase which causes SW620 cancer cells to develop polyploidy and increase in size following treatment, ultimately leading to cell death through apoptosis. Following treatment, the ADC values obtained by both the PGSE and low frequency OGSE methods increased. However, the ADC values at high gradient frequency (i.e. short diffusion times were significantly lower in treated tumors, consistent with increased intracellular restrictions/hindrances. This suggests that ADC values at long diffusion times are dominated by tumor microstructure at long length scales, and may not convey unambiguous information of subcellular space. While the diffusion temporal spectroscopy provides more comprehensive means to probe tumor microstructure at various length scales. This work is the first study to probe intracellular microstructural variations due to polyploidy following treatment using diffusion MRI in vivo. It is also the first observation of post-treatment ADC changes occurring in opposite directions at short and long diffusion times. The current study suggests that temporal diffusion spectroscopy potentially provides pharmacodynamic biomarkers of tumor early response which distinguish microstructural variations following

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

    CERN Document Server

    Ge, Li


    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...

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


    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.

  10. Effects of mean shear and scalar initial length scale on three-scalar mixing in turbulent coaxial jets (United States)

    Tong, Chenning; Li, Wei; Yuan, Mengyuan; Carter, Campbell


    We investigate three-scalar mixing in a turbulent coaxial jet, in which a center jet and an annular flow, consisting of acetone-doped air and ethylene respectively, are mixed with the co-flow air. We investigate the effects of the velocity and length scale ratios of the annular flow to the center jet. Planar laser-induced fluorescence and Rayleigh scattering are employed to image the scalars. The results show that the velocity ratio alters the relative mean shear rates in the mixing layers between the center jet and the annular flow and between the annular flow and the co-flow, modifying the scalar fields through mean-flow advection, turbulent transport, and small-scale mixing. The length scale ratio determines the degree of separation between the center jet and the co-flow. The results show that while varying the velocity ratio can alter the mixing characteristics qualitatively, varying the annulus width only has quantitative effects. The evolution of the mean scalar profiles are dominated by the mean-flow advection, while the shape of the joint probability density function is largely determined by the turbulent transport and molecular diffusion. The results in the present study have implications for understanding and modeling multiscalar mixing in turbulent reactive flows. Supported by NSF.

  11. Application of image processing for simulation of mechanical response of multi-length scale microstructures of engineering alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gokhale, A.M.; Yang, S. [Georgia Inst. of Tech., Atlanta, GA (United States). Dept. of Materials Science and Engineering


    Microstructures of engineering alloys often contain features at widely different length scales. In this contribution, a digital image processing technique is presented to incorporate the effect of features at higher length scales on the damage evolution and local fracture processes occurring at lower length scales. The method is called M-SLIP: Microstructural Scale Linking by Image Processing. The technique also enables incorporation of the real microstructure at different length scales in the finite element (FE)-based simulations. The practical application of the method is demonstrated via FE analysis on the microstructure of an aluminum cast alloy (A356), where the length scales of micropores and silicon particles differ by two orders of magnitude. The simulation captures the effect of nonuniformly distributed micropores at length scales of 200 to 500 {micro}m on the local stresses and strains around silicon particles that are at the length scales of 3 to 5 {micro}m. The procedure does not involve any simplifying assumptions regarding the microstructural geometry, and therefore, it is useful to model the mechanical response of the real multi-length scale microstructures of metals and alloys.

  12. Convergence of macroscopic tongue anatomy in ruminants and scaling relationships with body mass or tongue length. (United States)

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


    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.

  13. Fracture Testing at Small-Length Scales: From Plasticity in Si to Brittleness in Pt (United States)

    Jaya, B. Nagamani; Jayaram, Vikram


    The field of micro-/nano-mechanics of materials has been driven, on the one hand by the development of ever smaller structures in devices, and, on the other, by the need to map property variations in large systems that are microstructurally graded. Observations of `smaller is stronger' have also brought in questions of accompanying fracture property changes in the materials. In the wake of scattered articles on micro-scale fracture testing of various material classes, this review attempts to provide a holistic picture of the current state of the art. In the process, various reliable micro-scale geometries are shown, challenges with respect to instrumentation to probe ever smaller length scales are discussed and examples from recent literature are put together to exhibit the expanse of unusual fracture response of materials, from ductility in Si to brittleness in Pt. Outstanding issues related to fracture mechanics of small structures are critically examined for plausible solutions.

  14. 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: [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)


    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.

  15. Decoherence of trapped bosons by buffer gas scattering: What length scales matter?

    CERN Document Server

    Gilz, Lukas; Anglin, James R


    We ask and answer a basic question about the length scales involved in quantum decoherence: how far apart in space do two parts of a quantum system have to be, before a common quantum environment decoheres them as if they were entirely separate? We frame this question specifically in a cold atom context. How far apart do two populations of bosons have to be, before an environment of thermal atoms of a different species (`buffer gas') responds to their two particle numbers separately? An initial guess for this length scale is the thermal coherence length of the buffer gas; we show that a standard Born-Markov treatment partially supports this guess, but predicts only inverse-square saturation of decoherence rates with distance, and not the much more abrupt Gaussian behavior of the buffer gas's first-order coherence. We confirm this Born-Markov result with a more rigorous theory, based on an exact solution of a two-scatterer scattering problem, which also extends the result beyond weak scattering. Finally, howev...

  16. The Characteristics and Parameterization of Aerodynamic Roughness Length over Heterogeneous Surfaces

    Institute of Scientific and Technical Information of China (English)

    LU Li; LIU Shaomin; XU Ziwei; YANG Kun; CAI Xuhui; JIA Li; WANG Jiemin


    Aerodynamic roughness length (zOm) is a key factor in surface flux estimations with remote sensing algorithms and/or land surface models. This paper calculates zOm over several land surfaces, with 3 years of experimental data from Xiaotangshan. The results show that zOm is direction-dependent, mainly due to the heterogeneity of the size and spatial distribution of the roughness elements inside the source area along different wind directions. Furthermore, a heuristic parameterization of the aerodynamic roughness length for heterogeneous surfaces is proposed. Individual zOm over each surface component (patch) is calculated firstly with the characteristic parameters of the roughness elements (vegetation height, leaf area index, etc.), then zOm over the whole experimental field is aggregated, using the footprint weighting method.

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

    CERN Document Server

    He, Rong-Qiang


    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.

  18. 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


    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.

  19. Correlation length, universality classes, and scaling laws associated with topological phase transitions (United States)

    Chen, Wei; Legner, Markus; Rüegg, Andreas; Sigrist, Manfred


    The correlation functions related to topological phase transitions in inversion-symmetric lattice models described by 2 ×2 Dirac Hamiltonians are discussed. In one dimension, the correlation function measures the charge-polarization correlation between Wannier states at different positions, while in two dimensions it measures the itinerant-circulation correlation between Wannier states. The correlation function is nonzero in both the topologically trivial and nontrivial states, and allows us to extract a correlation length that diverges at topological phase transitions. The correlation length and the curvature function that defines the topological invariants are shown to have universal critical exponents, allowing the notion of universality classes to be introduced. Particularly in two dimensions, the universality class is determined by the orbital symmetry of the Dirac model. The scaling laws that constrain the critical exponents are revealed, and are predicted to be satisfied even in interacting systems, as demonstrated in an interacting topological Kondo insulator.

  20. 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


    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

  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


    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


    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. On the influence of free-stream turbulence length scales on boundary-layer transition (United States)

    Fransson, Jens; Shahinfar, Shahab


    A measurement campaign on the free-stream turbulence (FST) induced boundary layer transition has been carried out in the Minimum-Turbulence-Level wind tunnel at KTH. Previous numerical investigations where the turbulence intensity (Tu) has been kept constant, while the integral length scale (Λx) has been varied, have shown that the transition location is advanced for increasing Λx. The present measurement campaign has been carried out using hot-wire anemometry and consists of 42 unique FST conditions with thorough measurements throughout the transitional region. Unlike other extensive FST induced transition measurements the free-stream velocity was here kept constant for all cases, implying that the boundary layer scale is locked up to transition onset. Our measurements confirm previous results on the advancement of the transition location with increasing Λx for low to moderate Tu levels, but show the opposite effect for higher levels, i.e. a delay in the transition location for larger Λx, which to the knowledge of the present authors so far is unreported. In addition, the common belief that the FST length scales have a negligible effect on the transition location with regards to the Tu level does not seem to be fully true.

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

    Energy Technology Data Exchange (ETDEWEB)

    Mosey, Nicholas J. [Department of Mechanical and Aerospace Engineering and Program in Applied and Computational Mathematics, Princeton University, Princeton, NJ 08544-5263 (United States); Carter, Emily A., E-mail: [Department of Mechanical and Aerospace Engineering and Program in Applied and Computational Mathematics, Princeton University, Princeton, NJ 08544-5263 (United States)


    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 Cr{sub 2}O{sub 3} 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 {mu}m 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. Determination of critical length scales for corrosion processes using microelectroanalytical techniques.

    Energy Technology Data Exchange (ETDEWEB)

    Zavadil, Kevin Robert; Wall, Frederick Douglas


    A key factor in our ability to produce and predict the stability of metal-based macro- to nano-scale structures and devices is a fundamental understanding of the localized nature of corrosion. Corrosion processes where physical dimensions become critical in the degradation process include localized corrosion initiation in passivated metals, microgalvanic interactions in metal alloys, and localized corrosion in structurally complex materials like nanocrystalline metal films under atmospheric and inundated conditions. This project focuses on two areas of corrosion science where a fundamental understanding of processes occurring at critical dimensions is not currently available. Sandia will study the critical length scales necessary for passive film breakdown in the inundated aluminum (Al) system and the chemical processes and transport in ultra-thin water films relevant to the atmospheric corrosion of nanocrystalline tungsten (W) films. Techniques are required that provide spatial information without significantly perturbing or masking the underlying relationships. Al passive film breakdown is governed by the relationship between area of the film sampled and its defect structure. We will combine low current measurements with microelectrodes to study the size scale required to observe a single initiation event and record electrochemical breakdown events. The resulting quantitative measure of stability will be correlated with metal grain size, secondary phase size and distribution to understand which metal properties control stability at the macro- and nano-scale. Mechanisms of atmospheric corrosion on W are dependent on the physical dimensions and continuity of adsorbed water layers as well as the chemical reactions that take place in this layer. We will combine electrochemical and scanning probe microscopic techniques to monitor the chemistry and resulting material transport in these thin surface layers. A description of the length scales responsible for driving the

  6. A Generic Length-scale Equation For Second-order Turbulence Models of Oceanic Boundary Layers (United States)

    Umlauf, L.; Burchard, H.

    A generic transport equation for a generalized length-scale in second-order turbulence closure models for geophysical boundary layers is suggested. This variable consists of the products of powers of the turbulent kinetic energy, k, and the integral length-scale, l. The new approach generalizes traditional second-order models used in geophysical boundary layer modelling, e.g. the Mellor-Yamada model and the k- model, which, however, can be recovered as special cases. It is demonstrated how this new model can be calibrated with measurements in some typical geophysical boundary layer flows. As an example, the generic model is applied to the uppermost oceanic boundary layer directly influenced by the effects of breaking surface waves. Recent measurements show that in this layer the classical law of the wall is invalid, since there turbulence is dominated by turbulent transport of TKE from above, and not by shear-production. A widely accepted approach to describe the wave-affected layer with a one-equation turbulence model was suggested by Craig and Banner (1994). Here, some deficien- cies of their solutions are pointed out and a generalization of their ideas for the case of two-equation models is suggested. Direct comparison with very recently obtained measurements of the dissipation rate, , in the wave-affected boundary layer with com- puted results clearly demonstrate that only the generic two-equation model yields cor- rect predictions for the profiles of and the turbulent length scale, l. Also, the pre- dicted velocity profiles in the wave-affected layer, important e.g. for the interpretation of surface drifter experiments, are reproduced correctly only by the generic model. Implementation and computational costs of the generic model are comparable with traditonal two-equation models.

  7. Material length scales in gradient-dependent plasticity/damage and size effects: Theory and computation (United States)

    Abu Al-Rub, Rashid Kamel

    Structural materials display a strong size-dependence when deformed non-uniformly into the inelastic range: smaller is stronger. This effect has important implications for an increasing number of applications in structural failure, electronics, functional coatings, composites, micro-electro-mechanical systems (MEMS), nanostructured materials, micro/nanometer fabrication technologies, etc. The mechanical behavior of these applications cannot be characterized by classical (local) continuum theories because they incorporate no, 'material length scales' and consequently predict no size effects. On the other hand, it is still not possible to perform quantum and atomistic simulations on realistic time and structures. It is therefore necessary to develop a scale-dependent continuum theory bridging the gap between the classical continuum theories and the atomistic simulations in order to be able to design the size-dependent structures of modern technology. Nonlocal rate-dependent and gradient-dependent theories of plasticity and damage are developed in this work for this purpose. We adopt a multi-scale, hierarchical thermodynamic consistent framework to construct the material constitutive relations for the scale-dependent plasticity/damage behavior. Material length scales are implicitly and explicitly introduced into the governing equations through material rate-dependency (viscosity) and coefficients of spatial higher-order gradients of one or more material state variables, respectively. The proposed framework is implemented into the commercially well-known finite element software ABAQUS. The finite element simulations of material instability problems converge to meaningful results upon further refinement of the finite element mesh, since the width of the fracture process zone (shear band) is determined by the intrinsic material length scale; while the classical continuum theories fail to address this problem. It is also shown that the proposed theory is successful for

  8. Beam displacement as a function of temperature and turbulence length scale at two different laser radiation wavelengths. (United States)

    Isterling, William M; Dally, Bassam B; Alwahabi, Zeyad T; Dubovinsky, Miro; Wright, Daniel


    Narrow laser beams directed from aircraft may at times pass through the exhaust plume of the engines and potentially degrade some of the laser beam characteristics. This paper reports on controlled studies of laser beam deviation arising from propagation through turbulent hot gases, in a well-characterized laboratory burner, with conditions of relevance to aircraft engine exhaust plumes. The impact of the temperature, laser wavelength, and turbulence length scale on the beam deviation has been investigated. It was found that the laser beam displacement increases with the turbulent integral length scale. The effect of temperature on the laser beam angular deviation, σ, using two different laser wavelengths, namely 4.67 μm and 632.8 nm, was recorded. It was found that the beam deviation for both wavelengths may be semiempirically modeled using a single function of the form, σ=a(b+(1/T)(2))(-1), with two parameters only, a and b, where σ is in microradians and T is the temperature in °C.

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

    Hunt, A. G.


    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. Brief communication: Possible explanation of the values of Hack's drainage basin, river length scaling exponent (United States)

    Hunt, Allen G.


    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.

  11. 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)


    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.

  12. A multiple length scale description of the mechanism of elastomer stretching

    DEFF Research Database (Denmark)

    Neuefeind, J.; Skov, Anne Ladegaard; Daniels, J. E.


    Conventionally, the stretching of rubber is modeled exclusively by rotations of segments of the embedded polymer chains; i.e. changes in entropy. However models have not been tested on all relevant length scales due to a lack of appropriate probes. Here we present a universal X-ray based method...... within the individual monomers, but among the contributions is also an elastic strain, acting between chains, which is 3-4 orders of magnitude smaller than the macroscopic strain, and of the opposite sign, i.e. extension of polymer chains in the direction perpendicular to the stretch. This may be due...

  13. Optimal Heavy-Traffic Queue Length Scaling in an Incompletely Saturated Switch


    Maguluri, Siva Theja; Burle, Sai Kiran; Srikant, R.


    We consider an input queued switch operating under the MaxWeight scheduling algorithm. This system is interesting to study because it is a model for Internet routers and data center networks. Recently, it was shown that the MaxWeight algorithm has optimal heavy-traffic queue length scaling when all ports are uniformly saturated. Here we consider the case when an arbitrary number of ports are saturated (which we call the incompletely saturated case), and each port is allowed to saturate at a d...

  14. Lab on a chip Canada--rapid diffusion over large length scales. (United States)

    Juncker, David; Wheeler, Aaron R; Sinton, David


    The roots of lab on a chip in Canada are deep, comprising of some of the earliest contributions and first demonstrations of the potential of microfluidic chips. In an editorial leading off this special issue, Jed Harrison of University of Alberta reflects on these early days and Canada's role in the field's development (DOI: 10.1039/c3lc50522g). Over the last decade, microfluidics and lab-on-a-chip research efforts grew exponentially - rapidly diffusing across the vast Canadian length scales.

  15. Lead Selenide Nanostructures Self-Assembled across Multiple Length Scales and Dimensions

    Directory of Open Access Journals (Sweden)

    Evan K. Wujcik


    Full Text Available A self-assembly approach to lead selenide (PbSe structures that have organized across multiple length scales and multiple dimensions has been achieved. These structures consist of angstrom-scale 0D PbSe crystals, synthesized via a hot solution process, which have stacked into 1D nanorods via aligned dipoles. These 1D nanorods have arranged into nanoscale 2D sheets via directional short-ranged attraction. The nanoscale 2D sheets then further aligned into larger 2D microscale planes. In this study, the authors have characterized the PbSe structures via normal and cryo-TEM and EDX showing that this multiscale multidimensional self-assembled alignment is not due to drying effects. These PbSe structures hold promise for applications in advanced materials—particularly electronic technologies, where alignment can aid in device performance.

  16. Application of nonlocal models to nano beams. Part I: Axial length scale effect. (United States)

    Kim, Jun-Sik


    Applicability of nonlocal models to nano-beams is discussed in terms of physical implications via the similarity between a nonlocal Euler-Bernoulli (EB) beam theory and a classical Rankine-Timoshenko (RT) beam theory. The nonlocal EB beam model, Eringen's model, is briefly reviewed and the classical RT beam theory is recast by the primary variables of the EB model. A careful comparison of these two models reveals that the scale parameter used to the Eringen's model has a strike resemblance to the shear flexibility in the RT model. This implies that the nonlocal model employed in literature consider the axial length scale effect only. In addition, the paradox for a cantilevered nano-beam subjected to tip shear force is clearly explained by finding appropriate displacement prescribed boundary conditions.

  17. Characteristics, and carbon and nitrogen dynamics in soil irrigated with wastewater for different lengths of time. (United States)

    Ramirez-Fuentes, E; Lucho-constantino, C; Escamilla-Silva, E; Dendooven, L


    Irrigation of agricultural land with wastewater will increase crop production, but also heavy metal concentrations and the rate of infection of farmers with pathogens. The risks associated with the use of wastewater are reduced by treating the wastewater, but treatment also reduces organic material, phosphorus and inorganic N for crops. We investigated characteristics, e.g. heavy metal concentrations, of soils of the valley of the Mezquital (Mexico) irrigated with waste from Mexico City water since 1912, 1925, 1965, 1976, 1996 or 1997, or not irrigated at all, and dynamics of C and N when soil was amended with wastewater or drainage water. Concentrations of total Mg, Hg, Mo, Ca, Cu and Cr, available concentrations of Pb, Cd and Cu increased significantly with length of irrigation (P hazardous concentrations. Although organic C, total N, microbial biomass C and N, and microbial activity, as witnessed by CO2 production, increased with length of irrigation, N mineralization did not. Oxidation of NO2- was inhibited and could be due to increases in salinity, toxic compounds or heavy metals. We found that N mineralization was low or absent so it will not compensate for the loss of N when the wastewater is treated and application of N fertilizer will be required to maintain the same level of crop production. The characteristics of the soils appear not to have deteriorated after years of application of wastewater, but further irrigation even with treated wastewater might increase sodicity and salinity and pose a threat to future crop production.

  18. Relations between overturning length scales at the Spanish planetary boundary layer (United States)

    López, Pilar; Cano, José L.


    We analyze the behavior of the maximum Thorpe displacement (dT)max and the Thorpe scale LTat 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 m and 950 m for the different field campaigns. The maximum Thorpe displacement is always greater under convective conditions than under stable ones, independently of its sign. The Thorpe scale LT ranges between 0.2 m and 680 m for the different data sets which cover different stratified mixing conditions (turbulence shear-driven and convective regions). The Thorpe scale does not exceed several tens of meters under stable and neutral stratification conditions related to instantaneous density gradients. In contrast, under convective conditions, Thorpe scales are relatively large, they exceed hundreds of meters which may be related to convective bursts. We analyze the relation 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. References Cuxart, J., Yagüe, C., Morales, G., Terradellas, E., Orbe, J., Calvo, J., Fernández, A., Soler, M., Infante, C., Buenestado, P., Espinalt, Joergensen, H., Rees, J., Vilà, J., Redondo, J., Cantalapiedra, I. and Conangla, L.: Stable atmospheric boundary-layer experiment in Spain (Sables 98). A report, Boundary-Layer Meteorology, 96, 337-370, 2000. Dillon, T. M.: Vertical Overturns: A Comparison of Thorpe and Ozmidov Length Scales, J. Geophys. Res., 87(C12), 9601-9613, 1982. Itsweire, E. C.: Measurements of vertical overturns in stably stratified turbulent flow, Phys. Fluids, 27(4), 764-766, 1984. Kitade, Y., Matsuyama, M. and Yoshida, J.: Distribution of overturn induced by internal

  19. Characteristic Spatial Scales in Earthquake Data

    CERN Document Server

    Zöller, G; Hainzl, S; Kurths, J


    We present a new technique in order to quantify the dynamics of spatially extended systems. Using a test on the existence of unstable periodic orbits, we identify intermediate spatial scales, wherein the dynamics is characterized by maximum nontrivial determinism. This method is applied to earthquake catalogues containing time, coordinates and magnitude. As a result we extract a set of areas with significant deterministic and low-dimensional dynamics from the data. Finally, a simple model is used to show that these scales can be interpreted as local spatial coupling strengths.

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

    Indian Academy of Sciences (India)

    S M Yusuf


    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.

  1. Extraction of Channel Length Independent Series Resistance for Deeply Scaled Metal-Oxide-Semiconductor Field-Effect Transistors (United States)

    Ma, Li-Juan; Ji, Xiao-Li; Chen, Yuan-Cong; Xia, Hao-Guang; Zhu, Chen-Xin; Guo, Qiang; Yan, Feng


    The recently developed four Rsd extraction methods from a single device, involving the constant-mobility method, the direct Id—Vgs method, the conductance method and the Y-function method, are evaluated on 32 nm n-channel metal-oxide-semiconductor field-effect transistors (nMOSFETs). It is found that Rsd achieved from the constant-mobility method exhibits the channel length independent characteristics. The L-dependent Rsd extracted from the other three methods is proven to be associated with the gate-voltage-induced mobility degradation in the extraction procedures. Based on L-dependent behaviors of Rsd, a new method is proposed for accurate series resistance extraction on deeply scaled MOSFETs.

  2. Length measurement in absolute scale via low-dispersion optical cavity (United States)

    Pravdova, Lenka; Lesundak, Adam; Smid, Radek; Hrabina, Jan; Rerucha, Simon; Cip, Ondrej


    We report on the length measuring instrument with the absolute scale that was based on the combination of an optical frequency comb and a passive optical cavity. The time spacing of short femtosecond pulses, generated by the optical frequency comb, is optically phase locked onto the cavity free spectral range with a derivative spectroscopy technique so that the value of the repetition frequency of the femtosecond laser is tied to and determines the measured displacement. The instantaneous value of the femtosecond pulse train frequency is counted by a frequency counter. This counted value corresponds to the length given by the spacing between the two mirrors of the passive cavity. The phase lock between the femtosecond pulsed beam and the passive cavity is possible due to the low-dispersion of the cavity mirrors, where the silver coating on the mirrors was used to provide the low dispersion for the broadband radiation of the comb. Every reflection on the output mirror feeds a portion of the beam back to the cavity so that the output beam is a result of multiple interfering components. The parameters of the output beam are given not only by the parameters of the mirrors but mainly by the absolute distance between the mirror surfaces. Thus, one cavity mirror can be considered as the reference starting point of the distance to be measured and the other mirror is the measuring probe surveying the unknown distance. The measuring mirror of the experimental setup of the low-dispersion cavity is mounted on a piezoelectric actuator which provides small changes in the cavity length we used to test the length measurement method. For the verification of the measurement accuracy a reference incremental interferometer was integrated into our system so that the displacement of the piezoelectric actuator could be obtained with both measuring methods simultaneously.

  3. A simulation procedure for light-matter interaction at different length scales (United States)

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


    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

  4. Physician and hospital characteristics related to length of stay for sudden sensorineural hearing loss patients. (United States)

    Wu, Chuan-Song; Chao, Pin-Zhir; Lin, Herng-Ching


    The treatment of sudden sensorineural hearing loss (SSNHL) has remained one of the most controversial issues in otolaryngology, and there are wide disparities between clinicians' treatment methods for SSNHL. Using five-year population-based data, we explored the relationship between physician and hospital characteristics and the length of stay (LOS) for SSNHL patients in Taiwan. The dataset was derived from the National Health Insurance Research Database. The patients in the study sample were identified by a principal diagnosis of sudden hearing loss. A total of 8712 hospitalization cases between 1998 and 2002 inclusive were included. Multiple regression analyses were performed in order to explore the relationship between physician and hospital characteristics and LOS, adjusting for patients' age and gender, as well as complications or comorbidities. The mean LOS for the duration of the study period was 5.62 days, while the regression analysis showed that, as compared to district hospitals, the LOS in medical centers and regional hospitals was 0.42 and 0.37 days longer, respectively (all p patients who were attended by physicians specializing in otolaryngology than for those attended by physicians specializing in other areas (p characteristics and the LOS for SSNHL patients. The results of this study serve to highlight the importance of developing treatment protocols for SSNHL so as to reduce the variation in physician or hospital behavior.

  5. Circulating Leukocyte and Carotid Atherosclerotic Plaque Telomere Length Interrelation, Association With Plaque Characteristics, and Restenosis After Endarterectomy

    NARCIS (Netherlands)

    Huzen, Jardi; Peeters, Wouter; de Boer, Rudolf A.; Moll, Frans L.; Wong, Liza S. M.; Codd, Veryan; de Kleijn, Dominique P. V.; de Smet, Bart J. G. L.; van Veldhuisen, Dirk J.; Samani, Nilesh J.; van Gilst, Wiek H.; Pasterkamp, Gerard; van der Harst, Pim


    Objective-Shorter leukocyte telomeres are associated with atherosclerosis and predict future heart disease. The goal of the present study was to determine whether leukocyte telomere length is related to atherosclerotic plaque telomere length and whether it is associated with plaque characteristics o


    Energy Technology Data Exchange (ETDEWEB)

    Lam, P


    Finite element method was used to analyze the three-point bend experimental data of A533B-1 pressure vessel steel obtained by Sherry, Lidbury, and Beardsmore [1] from -160 to -45 C within the ductile-brittle transition regime. As many researchers have shown, the failure stress ({sigma}{sub f}) of the material could be approximated as a constant. The characteristic length, or the critical distance (r{sub c}) from the crack tip, at which {sigma}{sub f} is reached, is shown to be temperature dependent based on the crack tip stress field calculated by the finite element method. With the J-A{sub 2} two-parameter constraint theory in fracture mechanics, the fracture toughness (J{sub C} or K{sub JC}) can be expressed as a function of the constraint level (A{sub 2}) and the critical distance r{sub c}. This relationship is used to predict the fracture toughness of A533B-1 in the ductile-brittle transition regime with a constant {sigma}{sub f} and a set of temperature-dependent r{sub c}. It can be shown that the prediction agrees well with the test data for wide range of constraint levels from shallow cracks (a/W= 0.075) to deep cracks (a/W= 0.5), where a is the crack length and W is the specimen width.

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

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Sanae-I. [Research Institute for Applied Mechanics, Kyushu Univ., Kasuga, Fukuoka (Japan); Itoh, Kimitaka [National Inst. for Fusion Science, Toki, Gifu (Japan)


    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)

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

    CERN Document Server

    Licquia, Timothy C


    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 ...

  9. Kink stability, propagation, and length scale competition in the periodically modulated sine-Gordon equation

    CERN Document Server

    Sánchez, A; Domínguez-Adame, F; Angel Sanchez; Francisco Dominguez-Adame


    We have examined the dynamical behavior of the kink solutions of the one-dimensional sine-Gordon equation in the presence of a spatially periodic parametric perturbation. Our study clarifies and extends the currently available knowledge on this and related nonlinear problems in four directions. First, we present the results of a numerical simulation program which are not compatible with the existence of a radiative threshold, predicted by earlier calculations. Second, we carry out a perturbative calculation which helps interpret those previous predictions, enabling us to understand in depth our numerical results. Third, we apply the collective coordinate formalism to this system and demonstrate numerically that it accurately reproduces the observed kink dynamics. Fourth, we report on a novel occurrence of length scale competition in this system and show how it can be understood by means of linear stability analysis. Finally, we conclude by summarizing the general physical framework that arises from our study.

  10. Cellular adaptation to biomechanical stress across length scales in tissue homeostasis and disease. (United States)

    Gilbert, Penney M; Weaver, Valerie M


    Human tissues are remarkably adaptable and robust, harboring the collective ability to detect and respond to external stresses while maintaining tissue integrity. Following injury, many tissues have the capacity to repair the damage - and restore form and function - by deploying cellular and molecular mechanisms reminiscent of developmental programs. Indeed, it is increasingly clear that cancer and chronic conditions that develop with age arise as a result of cells and tissues re-implementing and deregulating a selection of developmental programs. Therefore, understanding the fundamental molecular mechanisms that drive cell and tissue responses is a necessity when designing therapies to treat human conditions. Extracellular matrix stiffness synergizes with chemical cues to drive single cell and collective cell behavior in culture and acts to establish and maintain tissue homeostasis in the body. This review will highlight recent advances that elucidate the impact of matrix mechanics on cell behavior and fate across these length scales during times of homeostasis and in disease states.

  11. Implementing structural slow light on short length scales: the photonic speed-bump

    CERN Document Server

    Faggiani, Remi; Hostein, Richard; Lalanne, Philippe


    One-dimensional (1D) infinite periodic systems exhibit vanishing group velocity and diverging density of states (DOS) near band edges. However, in practice, systems have finite sizes and inevitably this prompts the question of whether helpful physical quantities related to infinite systems, such as the group velocity that is deduced from the band structure, remain relevant in finite systems. For instance, one may wonder how the DOS divergence can be approached with finite systems. Intuitively, one may expect that the implementation of larger and larger DOS, or equivalently smaller and smaller group velocities, would critically increase the system length. Based on general 1D-wave-physics arguments, we demonstrate that the large slow-light DOS enhancement of periodic systems can be observed with very short systems, whose lengths scale with the logarithm of the inverse of the group velocities. The understanding obtained for 1D systems leads us to propose a novel sort of microstructure to enhance light-matter int...

  12. The effects of geometry and length scale on nanomechanical properties in constrained systems (United States)

    Jungk, John Michael


    The determination of mechanical properties in nanoscale geometries is becoming increasingly important as microsystem and integrated circuit technologies continue to mature. Many devices produced by these technologies are composed of materials with critical sample dimensions smaller than 100 nm. In microelectronics, this can be the thickness of a metallization or dielectric layer, while wear coatings on MEMS devices are frequently thinner than this length scale. Since structures of this type are susceptible to plasticity and fracture as a result of either contact or residual stresses, it is critical that the mechanical behavior of the individual components be well described. This thesis is directed at the development of methods for characterizing the mechanical properties in small volume systems. Using instrumented indentation techniques, typically called nanoindentation, a systematic study of the mechanical response of materials ranging from ductile metals to brittle ceramics was executed. More specifically, investigations into how single length scale approaches may be used to describe mechanical properties such as indentation hardening, ductile film delamination and strain energy release rates were performed. In addition, the acoustic energy released during the fracture of brittle ceramics was related to both stress intensity and a strain energy release rate. Finite element simulations of nanoindentation tests were performed using ABAQUS, a commercially available material modeling software program. These simulations were used to separate individual film and substrate responses from the experimentally observed film/substrate composite mechanical behavior. Finally, quasi-tribological experiments were performed to probe for transitions in friction or wear response as the local deformation varied from the nanoscale to the macroscale.


    Institute of Scientific and Technical Information of China (English)

    Yilong Bai; Mengfen Xia; Haiying Wang; Fujiu Ke


    Multi-scale modeling of materials properties and chemical processes has drawn great attention from science and engineering. For these multi-scale and rate-dependent processes, how to characterize their trans-scale formulation is a key point. Three questions should be addressed:● How do multi-sizes affect the problems?● How are length scales coupled with time scales?● How to identify emergence of new structure in process and its effect?For this sake, the macroscopic equations of mechanics and the kinetic equations of the microstructural transformations should form a unified set that be solved simultaneously.As a case study of coupling length and time scales, the trans-scale formulation of wave-induced damage evolution due to mesoscopic nucleation and growth is discussed. In this problem, the trans-scaling could be reduced to two independent dimensionless numbers: the imposed Deborah number De*=(ac*)/(LV*) and the intrinsic Deborah number D* = (nN*c*5)/V* , where a, L, c*, V* and nN* are wave speed, sample size, microcrack size, the rate of microcrack growth and the rate of microcrack nucleation density, respectively. Clearly, the dimensionless number De*=(ac*)/(LV*) includes length and time scales on both meso- and macro- levels and governs the progressive process.Whereas, the intrinsic Deborah number D* indicates the characteristic transition of microdamage to macroscopic rupture since D* is related to the criterion of damage localization, which is a precursor of macroscopic rupture. This case study may highlight the scaling in multi-scale and rate-dependent problems.Then, more generally, we compare some historical examples to see how trans-scale formulations were achieved and what are still open now. The comparison of various mechanisms governing the enhancement of meso-size effects reminds us of the importance of analyzing multi-scale and rate-dependent processes case by case.For multi-scale and rate-dependent processes with chemical reactions and

  14. Turbulent boundary layer over roughness transition with variation in spanwise roughness length scale (United States)

    Westerweel, Jerry; Tomas, Jasper; Eisma, Jerke; Pourquie, Mathieu; Elsinga, Gerrit; Jonker, Harm


    Both large-eddy simulations (LES) and water-tunnel experiments, using simultaneous stereoscopic PIV and LIF were done to investigate pollutant dispersion in a region where the surface changes from rural to urban roughness. This consists of rectangular obstacles where we vary the spanwise aspect ratio of the obstacles. A line source of passive tracer was placed upstream of the roughness transition. The objectives of the study are: (i) to determine the influence of the aspect ratio on the roughness-transition flow, and (ii) to determine the dominant mechanisms of pollutant removal from street canyons in the transition region. It is found that for a spanwise aspect ratio of 2 the drag induced by the roughness is largest of all considered cases, which is caused by a large-scale secondary flow. In the roughness transition the vertical advective pollutant flux is the main ventilation mechanism in the first three streets. Furthermore, by means of linear stochastic estimation the mean flow structure is identied that is responsible for exchange of the fluid between the roughness obstacles and the outer part of the boundary layer. Furthermore, it is found that the vertical length scale of this structure increases with increasing aspect ratio of the obstacles in the roughness region.

  15. Zebrafish brain mapping--standardized spaces, length scales, and the power of N and n. (United States)

    Hunter, Paul R; Hendry, Aenea C; Lowe, Andrew S


    Mapping anatomical and functional parameters of the zebrafish brain is moving apace. Research communities undertaking such studies are becoming ever larger and more diverse. The unique features, tools, and technologies associated with zebrafish are propelling them as the 21st century model organism for brain mapping. Uniquely positioned as a vertebrate model system, the zebrafish enables imaging of anatomy and function at different length scales from intraneuronal compartments to sparsely distributed whole brain patterns. With a variety of diverse and established statistical modeling and analytic methods available from the wider brain mapping communities, the richness of zebrafish neuroimaging data is being realized. The statistical power of population observations (N) within and across many samples (n) projected onto a standardized space will provide vast databases for data-driven biological approaches. This article reviews key brain mapping initiatives at different levels of scale that highlight the potential of zebrafish brain mapping. By way of introduction to the next wave of brain mappers, an accessible introduction to the key concepts and caveats associated with neuroimaging are outlined and discussed.

  16. A phenomenological description of BslA assemblies across multiple length scales. (United States)

    Morris, Ryan J; Bromley, Keith M; Stanley-Wall, Nicola; MacPhee, Cait E


    Intrinsically interfacially active proteins have garnered considerable interest recently owing to their potential use in a range of materials applications. Notably, the fungal hydrophobins are known to form robust and well-organized surface layers with high mechanical strength. Recently, it was shown that the bacterial biofilm protein BslA also forms highly elastic surface layers at interfaces. Here we describe several self-assembled structures formed by BslA, both at interfaces and in bulk solution, over a range of length scales spanning from nanometres to millimetres. First, we observe transiently stable and highly elongated air bubbles formed in agitated BslA samples. We study their behaviour in a range of solution conditions and hypothesize that their dissipation is a consequence of the slow adsorption kinetics of BslA to an air-water interface. Second, we describe elongated tubules formed by BslA interfacial films when shear stresses are applied in both a Langmuir trough and a rheometer. These structures bear a striking resemblance, although much larger in scale, to the elongated air bubbles formed during agitation. Taken together, this knowledge will better inform the conditions and applications of how BslA can be used in the stabilization of multi-phase materials.This article is part of the themed issue 'Soft interfacial materials: from fundamentals to formulation'.

  17. Evaluating the accuracy of finite element models at reduced length scales (United States)

    Kemp, Connor

    Finite element models are used frequently in both engineering and scientific research. While they can provide useful information as to the performance of materials, as length scales are decreased more sophisticated model descriptions are required. It is also important to develop methods by which existing models may be verified against experimental findings. The present study evaluates the ability of various finite element models to predict materials behaviour at length scales ranging from several microns to tens of nanometers. Considering this motivation, this thesis is provided in manuscript form with the bulk of material coming from two case studies. Following an overview of relevant literature in Chapter 2, Chapter 3 considers the nucleation of delta-zirconium hydrides in a Zircaloy-2 matrix. Zirconium hydrides are an important topic in the nuclear industry as they form a brittle phase which leads to delayed hydride cracking during reactor start-up and shut-down. Several FE models are used to compare present results with literature findings and illustrate the weaknesses of standard FE approaches. It is shown that standard continuum techniques do not sufficiently capture the interfacial effects of an inclusion-matrix system. By using nano-scale material descriptions, nucleation lattice strains are obtained which are in good agreement with previous experimental studies. The motivation for Chapter 4 stems from a recognized need to develop a method for modeling corrosion behaviour of materials. Corrosion is also an issue for reactor design and an ability to predict failure points is needed. Finite element models could be used for this purpose, provided model accuracy is verified first. In Chapter 4 a technique is developed which facilitates the extraction of sub-micron resolution strain data from correlation images obtained during in-situ tensile deformation. By comparing image correlation results with a crystal plasticity finite element code it is found that good

  18. Local scaling characteristics of Antarctic surface layer turbulence

    Directory of Open Access Journals (Sweden)

    S. Basu


    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.

  19. Failure analysis of fuel cell electrodes using three-dimensional multi-length scale X-ray computed tomography (United States)

    Pokhrel, A.; El Hannach, M.; Orfino, F. P.; Dutta, M.; Kjeang, E.


    X-ray computed tomography (XCT), a non-destructive technique, is proposed for three-dimensional, multi-length scale characterization of complex failure modes in fuel cell electrodes. Comparative tomography data sets are acquired for a conditioned beginning of life (BOL) and a degraded end of life (EOL) membrane electrode assembly subjected to cathode degradation by voltage cycling. Micro length scale analysis shows a five-fold increase in crack size and 57% thickness reduction in the EOL cathode catalyst layer, indicating widespread action of carbon corrosion. Complementary nano length scale analysis shows a significant reduction in porosity, increased pore size, and dramatically reduced effective diffusivity within the remaining porous structure of the catalyst layer at EOL. Collapsing of the structure is evident from the combination of thinning and reduced porosity, as uniquely determined by the multi-length scale approach. Additionally, a novel image processing based technique developed for nano scale segregation of pore, ionomer, and Pt/C dominated voxels shows an increase in ionomer volume fraction, Pt/C agglomerates, and severe carbon corrosion at the catalyst layer/membrane interface at EOL. In summary, XCT based multi-length scale analysis enables detailed information needed for comprehensive understanding of the complex failure modes observed in fuel cell electrodes.

  20. Asymptotic self-similar solutions with a characteristic time-scale

    CERN Document Server

    Waxman, Eli


    For a wide variety of initial and boundary conditions, adiabatic one dimensional flows of an ideal gas approach self-similar behavior when the characteristic length scale over which the flow takes place, $R$, diverges or tends to zero. It is commonly assumed that self-similarity is approached since in the $R\\to\\infty(0)$ limit the flow becomes independent of any characteristic length or time scales. In this case the flow fields $f(r,t)$ must be of the form $f(r,t)=t^{\\alpha_f}F(r/R)$ with $R\\propto(\\pm t)^\\alpha$. We show that requiring the asymptotic flow to be independent only of characteristic length scales imply a more general form of self-similar solutions, $f(r,t)=R^{\\delta_f}F(r/R)$ with $\\dot{R}\\propto R^\\delta$, which includes the exponential ($\\delta=1$) solutions, $R\\propto e^{t/\\tau}$. We demonstrate that the latter, less restrictive, requirement is the physically relevant one by showing that the asymptotic behavior of accelerating blast-waves, driven by the release of energy at the center of a co...

  1. Idealised numerical simulations of aerodynamic roughness length effects on sea breeze characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Prtenjak, M.T. [Zagreb Univ. (Croatia). Andrija Mohorovicic Geophysical Inst.


    A two-dimensional hydrostatic meso-{gamma}-scale model was used to study possible effects of a step change in roughness on the daytime sea breeze. Idealised numerical simulations with the length of aerodynamical roughness (z{sub 0}) ranging from 0.05 m to 1.0 m and by an increase of 0.05 m in all land grid points were made. Two z{sub 0} effects could be pointed out: an increase in the mixing process and a reduction in the wind speeds in the surface layer. An increase of both heights and magnitudes of the sea breeze circulation, caused by a vertical extension of the turbulent field, followed a faster inland penetration of the sea breeze. The second effect resulting from a successive increase in z{sub 0} values was a retardation of the sea breeze front near the ground, visible in its slope. This effect allowed the already faster inland penetration of the marine air high above the land. (orig.)

  2. Effect of growth rate on characteristic lengths of microstructure in directionally solidified

    Directory of Open Access Journals (Sweden)

    Zhang Yuan


    Full Text Available The microstructure of TiAl based alloys is sensitive to growth rates. In this paper, Bridgman directional solidification of Ti-46Al-2Cr-2Nb-0.2B (at.% alloy was carried out at a constant temperature gradient (G to investigate the effects of various growth rates (v on characteristic lengths (primary dendritic arm spacing, secondary dendritic arm spacing and lamellar spacing of the microstructure. Results show that under the experimental conditions of G = 18 K·m-1 and v = 15 μm·s-1 to 70 μm·s-1, the primary phase of directionally solidified Ti-46Al-2Cr-2Nb-0.2B alloy is α phase, the values of primary dendritic arm spacing (λ1, secondary dendritic arm spacing (λ2 and lamellar spacing (λ1a decrease with the increase in growth rate. The results were compared with theoretical models and similar experimental results of TiAl based alloys. The Bouchard-Kirkaldy model agrees well with the relationship between primary dendritic arm spacing and growth rate obtained in the experiment; the relationship between them can be expressed by λ1 = 758.6v-0.39. The relationship between the secondary dendritic arm spacing and the growth rate can be expressed by λ2 = 113.9v-0.45, while the relationship between the lamellar spacing and growth rate can be expressed by λ1a = 22.88v-0.94.

  3. Characteristic length of phonon transport within periodic nanoporous thin films and two-dimensional materials (United States)

    Hao, Qing; Xiao, Yue; Zhao, Hongbo


    In the past two decades, phonon transport within nanoporous thin films has attracted enormous attention for their potential applications in thermoelectrics and thermal insulation. Various computational studies have been carried out to explain the thermal conductivity reduction within these thin films. Considering classical phonon size effects, the lattice thermal conductivity can be predicted assuming diffusive pore-edge scattering of phonons and bulk phonon mean free paths. Following this, detailed phonon transport can be simulated for a given porous structure to find the lattice thermal conductivity [Hao et al., J. Appl. Phys. 106, 114321 (2009)]. However, such simulations are intrinsically complicated and cannot be used for the data analysis of general samples. In this work, the characteristic length Λ P o r e of periodic nanoporous thin films is extracted by comparing the predictions of phonon Monte Carlo simulations and the kinetic relationship using bulk phonon mean free paths modified by Λ P o r e . Under strong ballistic phonon transport, Λ P o r e is also extracted by the Monte Carlo ray-tracing method for graphene with periodic nanopores. The presented model can be widely used to analyze the measured thermal conductivities of such nanoporous structures.

  4. Characteristics of Gas Emission at Super-Length Fully-Mechanized Top Coal Caving Face

    Institute of Scientific and Technical Information of China (English)


    Characteristics of gas emission at the K8206 working face in the Third mine of the Yangquan Coal Group were investigated.The effects of strata movement, advancing velocity of working face, production capacity of working face and gas extraction capability of strike high-level entry on gas emission at K8206 working face were analyzed.A regression equation, reflecting the relationship between relative gas emission rate and the production capacity of working faces, was established.Another regression equation showing the relationship between the gas emission rate from adjacent layers when the working face was advancing for one metre and advancing velocity was derived.It can be concluded that, 1) the amount of gas emitted at the K8206 working face is far greater than that of ordinary top coal caving faces with a dip length of 180-190 m; 2) the dynamic process of gas emission from adjacent layers during the initial mining stage is controlled by the movement of key strata; 3) the amount of gas emitted that needs to be forced out by air is greatly affected by the capability of gas extraction; 4) when the advancing velocity is between 3.5-5.5 m/d or when the output is up to 8-12 kt/d, the gas emission from adjacent layers is almost constant.

  5. On scaling laws at the phase transition of systems with divergent order parameter and/or internal length the example of DNA denaturation

    CERN Document Server

    Buyukdagli, S; Buyukdagli, Sahin; Joyeux, Marc


    We used the Transfer-Integral method to compute, with an uncertainty smaller than 5%, the six fundamental characteristic exponents of two dynamical models for DNA thermal denaturation and investigate the validity of the scaling laws. Doubts concerning this point arise because the investigated systems (i) have a divergent internal length, (ii) are described by a divergent order parameter, (iii) are of dimension 1. We found that the assumption that the free energy can be described by a single homogeneous function is robust, despite the divergence of the order parameter, so that Rushbrooke's and Widom's identities are valid relations. Josephson's identity is instead not satisfied. This is probably due to the divergence of the internal length, which invalidates the assumption that the correlation length is solely responsible for singular contributions to thermodynamic quantities. Fisher's identity is even wronger. We showed that this is due to the d=1 dimensionality and obtained an alternative law, which is well ...

  6. On mechanics and material length scales of failure in heterogeneous interfaces using a finite strain high performance solver (United States)

    Mosby, Matthew; Matouš, Karel


    Three-dimensional simulations capable of resolving the large range of spatial scales, from the failure-zone thickness up to the size of the representative unit cell, in damage mechanics problems of particle reinforced adhesives are presented. We show that resolving this wide range of scales in complex three-dimensional heterogeneous morphologies is essential in order to apprehend fracture characteristics, such as strength, fracture toughness and shape of the softening profile. Moreover, we show that computations that resolve essential physical length scales capture the particle size-effect in fracture toughness, for example. In the vein of image-based computational materials science, we construct statistically optimal unit cells containing hundreds to thousands of particles. We show that these statistically representative unit cells are capable of capturing the first- and second-order probability functions of a given data-source with better accuracy than traditional inclusion packing techniques. In order to accomplish these large computations, we use a parallel multiscale cohesive formulation and extend it to finite strains including damage mechanics. The high-performance parallel computational framework is executed on up to 1024 processing cores. A mesh convergence and a representative unit cell study are performed. Quantifying the complex damage patterns in simulations consisting of tens of millions of computational cells and millions of highly nonlinear equations requires data-mining the parallel simulations, and we propose two damage metrics to quantify the damage patterns. A detailed study of volume fraction and filler size on the macroscopic traction-separation response of heterogeneous adhesives is presented.

  7. Intermediate length scale organisation in tin borophosphate glasses: new insights from high field correlation NMR. (United States)

    Tricot, G; Saitoh, A; Takebe, H


    The structure of tin borophosphate glasses, considered for the development of low temperature sealing glasses or anode materials for Li-batteries, has been analysed at the intermediate length scale by a combination of high field standard and advanced 1D/2D nuclear magnetic resonance techniques. The nature and extent of B/P mixing were analysed using the (11)B((31)P) dipolar heteronuclear multiple quantum coherence NMR sequence and the data interpretation allowed (i) detecting the presence and analysing the nature of the B-O-P linkages, (ii) re-interpreting the 1D (31)P spectra and (iii) extracting the proportion of P connected to borate species. Interaction between the different borate species was analysed using the (11)B double quantum-simple quantum experiment to (i) investigate the presence and nature of the B-O-B linkage, (ii) assign the different borate species observed all along the composition line and (iii) monitor the borate network formation. In addition, (119)Sn static NMR was used to investigate the evolution of the chemical environment of the tin polyhedra. Altogether, the set of data allowed determining the structural units constituting the glass network and quantifying the extent of B/P mixing. The structural data were then used to explain the non-linear and unusual evolution of the glass transition temperature.

  8. Short length scale mantle heterogeneity beneath Iceland probed by glacial modulation of melting (United States)

    Sims, Kenneth W. W.; Maclennan, John; Blichert-Toft, Janne; Mervine, Evelyn M.; Blusztajn, Jurek; Grönvold, Karl


    Glacial modulation of melting beneath Iceland provides a unique opportunity to better understand both the nature and length scale of mantle heterogeneity. At the end of the last glacial period, ∼13 000 yr BP, eruption rates were ∼20-100 times greater than in glacial or late postglacial times and geophysical modeling posits that rapid melting of the large ice sheet covering Iceland caused a transient increase in mantle decompression melting rates. Here we present the first time-series of Sr-Nd-Hf-Pb isotopic data for a full glacial cycle from a spatially confined region of basaltic volcanism in northern Iceland. Basalts and picrites erupted during the early postglacial burst of volcanic activity are systematically offset to more depleted isotopic compositions than those of lavas erupted during glacial or recent (Iceland is heterogeneous on small (glacial unloading indicates that the isotopic composition of mantle heterogeneities can be linked to their melting behavior. The present geochemical data can be accounted for by a melting model in which a lithologically heterogeneous mantle source contains an enriched component more fusible than its companion depleted component.

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

    Directory of Open Access Journals (Sweden)

    Riaz U. Ahmed


    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.

  10. A Test Of Newtonian Gravity At The 25 Micron Length Scale

    CERN Document Server

    Smullin, S J


    Several recent predictions of extra dimensions and exotic particles include Yukawa-type modifications to the classical Newtonian gravitational potential at length scales and magnitudes that may be accessible in tabletop experiments. To test these theories of physics beyond the Standard Model, we have built a probe to measure forces as small as 10−18 N between masses separated by distances on the order of 25 microns. The force sensor is a micromachined silicon cantilever. A gold test mass approximately (50 x 50 x 30) μm3 in size is glued to the end of the cantilever. An alternating pattern of gold and silicon bars is oscillated below the test mass; the coupling between the test mass and the varying gravitational field of the moving drive mass excites the cantilever on resonance. A fiber interferometer measures the cantilever motion and from this measurement, the force between the masses is deduced. The experiment is run at low temperatures in vacuum to reduce the thermal noise of the cantileve...

  11. 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


    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%.

  12. Comparison of the Effects of the Different Methods for Computing the Slope Length Factor at a Watershed Scale

    Directory of Open Access Journals (Sweden)

    Fu Suhua


    Full Text Available The slope length factor is one of the parameters of the Universal Soil Loss Equation (USLE and the Revised Universal Soil Loss Equation (RUSLE and is sometimes calculated based on a digital elevation model (DEM. The methods for calculating the slope length factor are important because the values obtained may depend on the methods used for calculation. The purpose of this study was to compare the difference in spatial distribution of the slope length factor between the different methods at a watershed scale. One method used the uniform slope length factor equation (USLFE where the effects of slope irregularities (such as slope gradient, etc. on soil erosion by water were not considered. The other method used segmented slope length factor equation(SSLFE which considered the effects of slope irregularities on soil erosion by water. The Arc Macro Language (AML Version 4 program for the revised universal soil loss equation(RUSLE.which uses the USLFE, was chosen to calculate the slope length factor. In a parallel analysis, the AML code of RUSLE Version 4 was modified according to the SSLFE to calculate the slope length factor. Two watersheds with different slope and gully densities were chosen. The results show that the slope length factor and soil loss using the USLFE method were lower than those using the SSLFE method, especially on downslopes watershed with more frequent steep slopes and higher gully densities. In addition, the slope length factor and soil loss calculated by the USLFE showed less spatial variation.

  13. 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;


    , the extent of this interaction was not different in the spastic rats. In conclusion, the effects of spasticity on length-force characteristics were muscle specific. The changes seen for GA and PL muscles are consistent with the changes in limb mechanics reported for human patients. Our results indicate......The purpose of the present study was to investigate muscle mechanical properties and mechanical interaction between muscles in the lower hindlimb of the spastic mutant rat. Length-force characteristics of gastrocnemius (GA), soleus (SO) and plantaris (PL) were assessed in anesthetized spastic...... and 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...

  14. Oscillatory Characteristics of Flow Rate in Cyclone Chambers of High Relative Length

    Directory of Open Access Journals (Sweden)

    A. Orekhov


    Full Text Available The paper describes an experimental investigation pertaining to distribution of oscillatory and averaged tangential and axial velocities of turbulent flow in cyclone chambers of high relative length. It has been shown that as in the chambers of relatively small length (close to unit length general level of velocity pulsation intensity significantly exceeds the level observed in the chambers of analogous use with non-tightened-up heat carrier.

  15. One Type of Dynamic Scaling Characteristics for Synchronizability in LUHVGM

    Institute of Scientific and Technical Information of China (English)

    LIU; Qiang; FANG; Jin-qing; LI; Yong


    <正>The third level of unified hybrid network theoretical framework so-called large unifying hybrid variable growing model (LUHVGM) can be used to research basic characteristics of some social networks and high technology enterprise networks in theory as we investigated before. The research of dynamical synchronization is an important issue, which can rich and understand the characteristic of the LUHVGM. We found that the dynamical scaling relation and its exponent γ can be applied to describe the

  16. Application of the linear/exponential hybrid force field scaling scheme to the bond length alternation modes of polyacetylene (United States)

    Yang, Shujiang; Kertesz, Miklos


    The two bond length alternation related backbone carbon-carbon stretching Raman active normal modes of polyacetylene are notoriously difficulty to predict theoretically. We apply our new linear/exponential scaled quantum mechanical force field scheme to tackle this problem by exponentially adjusting the decay of the coupling force constants between backbone stretchings based on their distance which extends over many neighbors. With transferable scaling parameters optimized by least squares fitting to the experimental vibrational frequencies of short oligoenes, the scaled frequencies of trans-polyacetylene and its isotopic analogs agree very well with experiments. The linear/exponential scaling scheme is also applicable to the cis-polyacetylene case.

  17. Statistical theory and transition in multiple-scale-length turbulence in plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Sanae-I [Research Institute for Applied Mechanics, Kyushu University, Kasuga (Japan); Itoh, Kimitaka [National Institute for Fusion Science, Toki (Japan)


    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 the 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 at a suppressed level. A 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. The influence of the inhomogeneous global radial electric field is discussed. A new insight is given for the physics of the internal transport barrier. Finally, the non-local heat transport due to the long-wavelength fluctuations, which are noise-pumped by shorter-wavelength fluctuations, is analysed and its impact on transient transport problems is discussed. (author)

  18. Compositional variations at ultra-structure length scales in coral skeleton (United States)

    Meibom, Anders; Cuif, Jean-Pierre; Houlbreque, Fanny; Mostefaoui, Smail; Dauphin, Yannicke; Meibom, Karin L.; Dunbar, Robert


    Distributions of Mg and Sr in the skeletons of a deep-sea coral ( Caryophyllia ambrosia) and a shallow-water, reef-building coral ( Pavona clavus) have been obtained with a spatial resolution of 150 nm, using the NanoSIMS ion microprobe at the Muséum National d'Histoire Naturelle in Paris. These trace element analyses focus on the two primary ultra-structural components in the skeleton: centers of calcification (COC) and fibrous aragonite. In fibrous aragonite, the trace element variations are typically on the order of 10% or more, on length scales on the order of 1-10 μm. Sr/Ca and Mg/Ca variations are not correlated. However, Mg/Ca variations in Pavona are strongly correlated with the layered organization of the skeleton. These data allow for a direct comparison of trace element variations in zooxanthellate and non-zooxanthellate corals. In both corals, all trace elements show variations far beyond what can be attributed to variations in the marine environment. Furthermore, the observed trace element variations in the fibrous (bulk) part of the skeletons are not related to the activity of zooxanthellae, but result from other biological activity in the coral organism. To a large degree, this biological forcing is independent of the ambient marine environment, which is essentially constant on the growth timescales considered here. Finally, we discuss the possible detection of a new high-Mg calcium carbonate phase, which appears to be present in both deep-sea and reef-building corals and is neither aragonite nor calcite.

  19. In situ spatiotemporal mapping of flow fields around seeded stem cells at the subcellular length scale.

    Directory of Open Access Journals (Sweden)

    Min Jae Song

    Full Text Available A major hurdle to understanding and exploiting interactions between the stem cell and its environment is the lack of a tool for precise delivery of mechanical cues concomitant to observing sub-cellular adaptation of structure. These studies demonstrate the use of microscale particle image velocimetry (μ-PIV for in situ spatiotemporal mapping of flow fields around mesenchymal stem cells, i.e. murine embryonic multipotent cell line C3H10T1/2, at the subcellular length scale, providing a tool for real time observation and analysis of stem cell adaptation to the prevailing mechanical milieu. In the absence of cells, computational fluid dynamics (CFD predicts flow regimes within 12% of μ-PIV measures, achieving the technical specifications of the chamber and the flow rates necessary to deliver target shear stresses at a particular height from the base of the flow chamber. However, our μ-PIV studies show that the presence of cells per se as well as the density at which cells are seeded significantly influences local flow fields. Furthermore, for any given cell or cell seeding density, flow regimes vary significantly along the vertical profile of the cell. Hence, the mechanical milieu of the stem cell exposed to shape changing shear stresses, induced by fluid drag, varies with respect to proximity of surrounding cells as well as with respect to apical height. The current study addresses a previously unmet need to predict and observe both flow regimes as well as mechanoadaptation of cells in flow chambers designed to deliver precisely controlled mechanical signals to live cells. An understanding of interactions and adaptation in response to forces at the interface between the surface of the cell and its immediate local environment may be key for de novo engineering of functional tissues from stem cell templates as well as for unraveling the mechanisms underlying multiscale development, growth and adaptation of organisms.

  20. Role of length scales on microwave thawing dynamics in 2D cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Basak, T.; Ayappa, K.G. [Indian Institute of Science, Bangalore (India). Department of Chemical Engineering


    Microwave (MW) thawing of 2D frozen cylinders exposed to uniform plane waves from one face, is modeled using the effective heat capacity formulation with the MW power obtained from the electric field equations. Computations are illustrated for tylose (23% methyl cellulose gel) which melts over a range of temperatures giving rise to a mushy zone. Within the mushy region the dielectric properties are functions of the liquid volume fraction. The resulting coupled, time dependent non-linear equation are solved using the Galerkin finite element method with a fixed mesh. Our method efficiently captures the multiple connected thawed domains that arise due to the penetration of MWs in the sample. For a cylinder of diameter D, the two length scales that control the thawing dynamics are D/D{sub p}, and D/{lambda}{sub m}, where D{sub p} and {lambda}{sub m} are the penetration depth and wavelength of radiation in the sample respectively. For D/D{sub p}, D/{lambda}{sub m}<<1 power absorption is uniform and thawing occurs almost simultaneously across the sample (Regime I). For D/D{sub p}>>1 thawing is seen to occur from the incident face, since the power decays exponentially into the sample (Regime III). At intermediate values, 0.2

  1. Exploring soil organic matter-mineral interactions: mechanistic insights at the nanometer and molecular length scales (United States)

    Newcomb, C.; Qafoku, N. P.; Grate, J. W.; Hufschmid, R.; Browning, N.; De Yoreo, J. J.


    With elevated levels of carbon dioxide in the atmosphere due to anthropogenic emissions and disruption to the carbon cycle, the effects of climate change are being accelerated. Approximately 80% of Earth's terrestrial organic carbon is stored in soil, and the residence time of this carbon can range from hours to millenia. Understanding the dynamics of this carbon pool in the carbon cycle is crucial to both predicting climate and sustaining ecosystem services. Soil organic carbon is known to be strongly associated with high surface area clay minerals. The nature of these interactions is not well understood primarily due to the heterogeneity of soil, as much of the current knowledge relies on experiments that take a top-down approach using bulk experimental measurements. Our work seeks to probe physical, chemical, and molecular-level interactions at the organic-mineral interface using a bottom-up approach that establishes a model system where complexity can be built in systematically. By performing in situ techniques such as dynamic force spectroscopy, a technique where organic molecules can be brought into contact with mineral surfaces in a controlled manner using an atomic force microscope, we demonstrate the ability to mechanistically probe the energy landscape of individual organic molecules with mineral surfaces. We demonstrate the ability to measure the binding energies of soil-inspired organic functional groups (including carboxylic acid, amine, methyl, and phosphate) with clay and mineral surfaces as a function of solution chemistry. This effort can provide researchers with both guiding principles about carbon dynamics at the sub-nanometer length scale and insights into early aggregation events, where organic-mineral interactions play a significant role.

  2. Frequency-Wavenumber Velocity Spectra, Taylor's Hypothesis and Length-Scales in a Natural Gravel-Bed River (United States)

    Thornton, E. B.; MacMahan, J. H.; Reniers, A. J.; Ashley, W.


    Macro-scale turbulent coherent flow structures in a natural fast-flowing river were examined with a combination of a novel 2 MHz Acoustic Doppler Beam (ADB) and a Maximum Likelihood Estimator (MLE) to characterize the stream-wise horizontal length scales and persistence of coherent flow structures by measuring the frequency (f)- streamwise-wavenumber (k) energy density velocity spectrum, E(f,k ), for the first time in natural rivers. The ADB was deployed under a range of Froude numbers (0.1-0.6) at high Reynolds Numbers based on depth and velocity conditions within a gravel-bed reach of the Kootenai River, ID. The MLE employed on the ADB data increased our ability to describe river motions with relatively long (>10 m) length scales in ~1 m water depths. The E(f,k) fall along a ridge described by V=f/k, where V is the mean velocity over depth, verifying Taylor's hypothesis. New, consistent length scale measures are defined based on averaged wave lengths of the low frequency E(f,k) and coherence spectra. Energetic (~50% of the total spectral energy), low-frequency (f1 m/s, L were found to be significantly longer than their corresponding coherence lengths suggesting that the turbulent structures evolve rapidly under these conditions. This is attributed to the stretching and concomitant deformation of pre-existing macro-turbulent motions by the ubiquitous bathymetry-induced spatial flow accelerations present in a natural gravel-bed river.Mean motion lengths, Lm, (circles) and coherence lengths, Lc, (squares) as a function of the mean streamwise velocity at locations in Zones 1-4.

  3. Estimation of active force-length characteristics of human vastus lateralis muscle. (United States)

    Ichinose, Y; Kawakami, Y; Ito, M; Fukunaga, T


    The length and angles of fascicles were determined for the vastus lateralis muscle (VL) using ultrasonography in 6 subjects performing ramp isometric knee extension. The subject increased torque from zero (relax) to maximum (MVC) with the knee positioned every 15 degrees, from 10 degrees to 100 degrees flexion (0 degrees = full extension). As the knee was positioned closer to extension, fascicle length was shorter [116 +/- 4.7 (mean +/- SEM) mm at 100 degrees vs. 88 +/- 4.1 mm at 10 degrees (relax)]. The fascicle length of the VL decreased with increasing torque at each knee position [116 +/- 4.7 (relax) to 92 +/- 4.3 mm (MVC) at 100 degrees]. On the other hand, fascicle angles increased with an increase in torque. These changes reflected the compliance of the muscle-tendon complex which increased as the knee reached a straight position. The estimated muscle force of the VL was maximal (2,052 +/- 125 N) for a fascicle length of 78 +/- 2.7 mm (i.e. optimum length) with the knee positioned at 70 degrees of flexion. The relationship between muscle force and fascicle length indicated that the VL uses the ascending (knee 70 degrees) of the force-length curve.

  4. Plasma-field Coupling at Small Length Scales in Solar Wind Near 1 AU (United States)

    Livadiotis, G.; Desai, M. I.


    In collisionless plasmas such as the solar wind, the coupling between plasma constituents and the embedded magnetic field occurs on various temporal and spatial scales, and is primarily responsible for the transfer of energy between waves and particles. Recently, it was shown that the transfer of energy between solar wind plasma particles and waves is governed by a new and unique relationship: the ratio between the magnetosonic energy and the plasma frequency is constant, E ms/ω pl ˜ ℏ*. This paper examines the variability and substantial departure of this ratio from ℏ* observed at ˜1 au, which is caused by a dispersion of fast magnetosonic (FMS) waves. In contrast to the efficiently transferred energy in the fast solar wind, the lower efficiency of the slow solar wind can be caused by this dispersion, whose relation and characteristics are derived and studied. In summary, we show that (i) the ratio E ms/ω pl transitions continuously from the slow to the fast solar wind, tending toward the constant ℏ* (ii) the transition is more efficient for larger thermal, Alfvén, or FMS speeds; (iii) the fast solar wind is almost dispersionless, characterized by quasi-constant values of the FMS speed, while the slow wind is subject to dispersion that is less effective for larger wind or magnetosonic speeds; and (iv) the constant ℏ* is estimated with the best known precision, ℏ* ≈ (1.160 ± 0.083) × 10-22 Js.

  5. Dominant length scale of the ``pure'' turbulent fluctuations in the outer region of wall turbulence (United States)

    Kwon, Yong Seok; Monty, Jason; Hutchins, Nick


    A new method of decomposing the total velocity in boundary layers, which removes the influence of instantaneous boundary layer thickness variations to the fluctuating velocity component, is proposed. The recent proposition of the quiescent core of turbulent channel flow by Kwon et al. (J. Fluid Mech., 751, 228 (2014)) permits us to apply the same decomposition to channel flows where the quiescent core is analogous to the free-stream. Using this decomposition, it is observed that the majority of the large-scale streamwise velocity fluctuation within the intermittent region is attributed to the oscillation of the turbulent/non-turbulent interface or the quiescent core. It suggests that the quiescent core and the free-stream play a similar role and the flow nearer to the wall in both flows is more similar than previously thought while the different characteristics of the free-stream and the quiescent core account for the differences in the outer region of two flows. These findings re-affirm the analogy between the quiescent core and the free-stream, which could potentially lead to the unified conceptual model between internal and external flows. This work is financially supported by the Australian Research Council and the Defence Science and Technology Organisation.

  6. Determining pore length scales and pore surface relaxivity of rock cores by internal magnetic fields modulation at 2MHz NMR. (United States)

    Liu, Huabing; Nogueira d'Eurydice, Marcel; Obruchkov, Sergei; Galvosas, Petrik


    Pore length scales and pore surface relaxivities of rock cores with different lithologies were studied on a 2MHz Rock Core Analyzer. To determine the pore length scales of the rock cores, the high eigenmodes of spin bearing molecules satisfying the diffusion equation were detected with optimized encoding periods in the presence of internal magnetic fields Bin. The results were confirmed using a 64MHz NMR system, which supports the feasibility of high eigenmode detection at fields as low as 2MHz. Furthermore, this methodology was combined with relaxometry measurements to a two-dimensional experiment, which provides correlation between pore length and relaxation time. This techniques also yields information on the surface relaxivity of the rock cores. The estimated surface relaxivities were then compared to the results using an independent NMR method.

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

    Directory of Open Access Journals (Sweden)

    Jun-Ha LEE


    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:

  8. Cation ratio fluctuations in Cu2ZnSnS4 at the 20 nm length scale investigated by analytical electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Jeffery A. [National Renewable Energy Laboratory, Golden CO 80401 USA; Erkan, Mehmet E. [Department of Electrical and Computer Engineering, University of Utah, UT 84112 USA; Pruzan, Dennis S. [Department of Materials Science and Engineering, University of Utah, UT 84112 USA; Nagaoka, Akira [Department of Materials Science and Engineering, University of Utah, UT 84112 USA; Department of Applied Physics and Electronic Engineering, University of Miyazaki, Miyazaki 889 2192 Japan; Yoshino, Kenji [Department of Applied Physics and Electronic Engineering, University of Miyazaki, Miyazaki 889 2192 Japan; Moutinho, Helio [National Renewable Energy Laboratory, Golden CO 80401 USA; Al-Jassim, Mowafak [National Renewable Energy Laboratory, Golden CO 80401 USA; Scarpulla, Michael A. [Department of Electrical and Computer Engineering, University of Utah, UT 84112 USA; Department of Materials Science and Engineering, University of Utah, UT 84112 USA


    Kesterite Cu2ZnSn(S,Se)4 (CZTSSe) is a sustainable material for thin-film photovoltaics with device efficiencies greater than 12% have been demonstrated. Despite similar crystal structure and polycrystalline film microstructures, there is widespread evidence for larger-amplitude potential and bandgap fluctuations in CZTS than in the analogous Cu(In,Ga)Se2 (CIGSe) chalcopyrite material. This disorder is believed to account for a sizable part of the larger open-circuit voltage (VOC) deficit in CZTS devices, yet the detailed origins and length scales of these fluctuations have not been fully elucidated. Herein, we present a transmission electron microscopy study focusing on composition variation within bulk multicrystals of CZTS grown by the travelling heater method (THM). In these slow-cooled, solution grown crystals we find direct evidence for spatial composition fluctuations of amplitude <1 at.% (~5 x 1020 cm-3) and thus, explainable by point defects. However, rather than being homogeneously-distributed we find a characteristic 20 nm length scale for these fluctuations, which sets a definite length scale for band gap and potential fluctuations. At Σ3 grain boundaries, we find no evidence of composition variation compared to the bulk. The finding highlights such variations reported at grain boundaries in polycrystalline thin-films are direct consequences of processing methods and not intrinsic properties of CZTS itself.

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

    KAUST Repository

    Liu, Junxian


    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

  10. Effect of regional lung inflation on ventilation heterogeneity at different length scales during mechanical ventilation of normal sheep lungs. (United States)

    Wellman, Tyler J; Winkler, Tilo; Costa, Eduardo L V; Musch, Guido; Harris, R Scott; Venegas, Jose G; Vidal Melo, Marcos F


    Heterogeneous, small-airway diameters and alveolar derecruitment in poorly aerated regions of normal lungs could produce ventilation heterogeneity at those anatomic levels. We modeled the washout kinetics of (13)NN with positron emission tomography to examine how specific ventilation (sV) heterogeneity at different length scales is influenced by lung aeration. Three groups of anesthetized, supine sheep were studied: high tidal volume (Vt; 18.4 ± 4.2 ml/kg) and zero end-expiratory pressure (ZEEP) (n = 6); low Vt (9.2 ± 1.0 ml/kg) and ZEEP (n = 6); and low Vt (8.2 ± 0.2 ml/kg) and positive end-expiratory pressure (PEEP; 19 ± 1 cmH(2)O) (n = 4). We quantified fractional gas content with transmission scans, and sV with emission scans of infused (13)NN-saline. Voxel (13)NN-washout curves were fit with one- or two-compartment models to estimate sV. Total heterogeneity, measured as SD[log(10)(sV)], was divided into length-scale ranges by measuring changes in variance of log(10)(sV), resulting from progressive filtering of sV images. High-Vt ZEEP showed higher sV heterogeneity at 36-mm (r = -0.72) length scales (P < 0.001). We conclude that sV heterogeneity at length scales <60 mm increases in poorly aerated regions of mechanically ventilated normal lungs, likely due to heterogeneous small-airway narrowing and alveolar derecruitment. PEEP reduces sV heterogeneity by maintaining lung expansion and airway patency at those small length scales.

  11. 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.


    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.

  12. Muscle-specific changes in length-force characteristics of the calf muscles in the spastic Han-Wistar rat. (United States)

    Olesen, Annesofie T; Jensen, Bente R; Uhlendorf, Toni L; Cohen, Randy W; Baan, Guus C; Maas, Huub


    The purpose of the present study was to investigate muscle mechanical properties and mechanical interaction between muscles in the lower hindlimb of the spastic mutant rat. Length-force characteristics of gastrocnemius (GA), soleus (SO), and plantaris (PL) were assessed in anesthetized spastic and 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 curves 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 and PL. However, the extent of this interaction was not different in spastic rats. In conclusion, the effects of spasticity on length-force characteristics were muscle specific. The changes observed for GA and PL muscles are consistent with the changes in limb mechanics reported for human patients. Our results indicate that altered mechanics in spastic rats cannot be attributed to differences in mechanical interaction, but originate from individual muscular structures.

  13. 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


    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.

  14. The relationship between telomere length and clinicopathologic characteristics in colorectal cancers among Tunisian patients. (United States)

    Mzahma, Raja; Kharrat, Maher; Fetiriche, Fadhel; Bouasker; Ben Moussa, Mounir; Ben Safta, Zoubeir; Dziri, Chadli; Zaouche, AbdelJelil; Chaabouni-Bouhamed, Habiba


    Alterations in telomere dynamics have emerged as having a causative role in carcinogenesis. Both the telomere attrition contribute to tumor initiation via increasing chromosomal instability and that the telomere elongation induces cell immortalization and leads to tumor progression. The objectives of this study are to investigate the dynamics of telomere length in colorectal cancer (CRC) and the clinicopathological parameters implicated. We measured the relative telomere length (RTL) in cancerous tissues and in corresponding peripheral blood leukocytes (PBL) using quantitative PCR (Q-PCR) from 94 patients with CRC. Telomere length correlated significantly in cancer tissues and corresponding PBL (r = 0.705). Overall, cancer tissue had shorter telomeres than PBL (p = 0.033). In both cancer tissue and PBL, the RTL was significantly correlated with age groups (p = 0.008 and p = 0.012, respectively). The RTL in cancer tissue was significantly longer in rectal tumors (p = 0.04) and in the late stage of tumors (p = 0.01). In PBL, the RTL was significantly correlated with the macroscopic aspect of tumors (p = 0.02). In addition, the telomere-length ratio of cancer to corresponding PBL increased significantly with late-stage groups. Shortening of the telomere was detected in 44.7%, elongation in 36.2%, and telomeres were unchanged in 19.1% of 94 tumors. Telomere shortening occurred more frequently in the early stage of tumors (p = 0.01). This study suggests that the telomere length in PBL is affected by the macroscopic aspect of tumors and that telomere length in cancer tissues is a marker for progression of CRC and depends on tumor-origin site.

  15. Scaling between superconducting critical temperature and structural coherence length in YBa2Cu3O6.9 films (United States)

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


    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.

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

    Directory of Open Access Journals (Sweden)

    Gottfried Mayer-Kress


    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.

  17. Chain length distribution and kinetic characteristics of an enzymatically produced polymer

    NARCIS (Netherlands)

    Mulders, K.J.M.; Beeftink, H.H.


    Non-processive enzymatic polymerization leads to a distribution of polymer chain lengths. A polymerization model was developed to investigate the relation between the extent of this distribution on one hand, and the polymerization start conditions and reaction kinetics on the other hand. The model d

  18. Dependence of displacement-length scaling relations for fractures and deformation bands on the volumetric changes across them (United States)

    Schultz, R.A.; Soliva, R.; Fossen, H.; Okubo, C.H.; Reeves, D.M.


    Displacement-length data from faults, joints, veins, igneous dikes, shear deformation bands, and compaction bands define two groups. The first group, having a power-law scaling relation with a slope of n = 1 and therefore a linear dependence of maximum displacement and discontinuity length (Dmax = ??L), comprises faults and shear (non-compactional or non-dilational) deformation bands. These shearing-mode structures, having shearing strains that predominate over volumetric strains across them, grow under conditions of constant driving stress, with the magnitude of near-tip stress on the same order as the rock's yield strength in shear. The second group, having a power-law scaling relation with a slope of n = 0.5 and therefore a dependence of maximum displacement on the square root of discontinuity length (Dmax = ??L0.5), comprises joints, veins, igneous dikes, cataclastic deformation bands, and compaction bands. These opening- and closing-mode structures grow under conditions of constant fracture toughness, implying significant amplification of near-tip stress within a zone of small-scale yielding at the discontinuity tip. Volumetric changes accommodated by grain fragmentation, and thus control of propagation by the rock's fracture toughness, are associated with scaling of predominantly dilational and compactional structures with an exponent of n = 0.5. ?? 2008 Elsevier Ltd.

  19. Static and dynamic length scales in supercooled liquids: insights from molecular dynamics simulations of water and tri-propylene oxide. (United States)

    Klameth, F; Henritzi, P; Vogel, M


    We perform molecular dynamics simulations to study static and dynamic length scales in molecular supercooled liquids, in particular, water. For a determination of these scales, we use equilibrium configurations and pin appropriate subsets of molecules so as to obtain random matrices, cylindrical pores, and slit confinements. Static length scales ξ(s) are determined by analyzing overlap correlation functions for various fractions of pinned molecules or distances to the confining walls. For water in all confinements and for propylene oxide trimers in random geometry, a linear increase of ξ(s) with inverse temperature is found. Dynamic length scales ξ(d) are determined by analogous analysis of fraction-dependent or position-resolved correlation times of structural relaxation. While ξ(d) continuously grows upon cooling in the cylindrical and slit confinements, we find no evidence for a temperature dependence in random matrices, implying that molecular dynamics in parsed volumes is qualitatively different from that in bulk liquids. Finally, we study possible connections between the growth of the static and dynamic length scales and the slowdown of the structural relaxation of the supercooled bulk liquids. For water, we observe a linear relation between ln τ(α) and ξ(s)²/T in the whole accessible range down to the critical temperature of mode-coupling theory, T(c). In the weakly supercooled regime, the same relation holds also for ξ(d), as obtained from cylindrical and slit confinements, but deviations from this behavior are observed near T(c). The results are discussed in connection with random first-order theory and experimental studies of liquid dynamics in nanoscopic confinements and binary mixtures.

  20. Pollutant Dispersion in Boundary Layers Exposed to Rural-to-Urban Transitions: Varying the Spanwise Length Scale of the Roughness (United States)

    Tomas, J. M.; Eisma, H. E.; Pourquie, M. J. B. M.; Elsinga, G. E.; Jonker, H. J. J.; Westerweel, J.


    Both large-eddy simulations (LES) and water-tunnel experiments, using simultaneous stereoscopic particle image velocimetry and laser-induced fluorescence, have been used to investigate pollutant dispersion mechanisms in regions where the surface changes from rural to urban roughness. The urban roughness was characterized by an array of rectangular obstacles in an in-line arrangement. The streamwise length scale of the roughness was kept constant, while the spanwise length scale was varied by varying the obstacle aspect ratio l / h between 1 and 8, where l is the spanwise dimension of the obstacles and h is the height of the obstacles. Additionally, the case of two-dimensional roughness (riblets) was considered in LES. A smooth-wall turbulent boundary layer of depth 10h was used as the approaching flow, and a line source of passive tracer was placed 2h upstream of the urban canopy. The experimental and numerical results show good agreement, while minor discrepancies are readily explained. It is found that for l/h=2 the drag induced by the urban canopy is largest of all considered cases, and is caused by a large-scale secondary flow. In addition, due to the roughness transition the vertical advective pollutant flux is the main ventilation mechanism in the first three streets. Furthermore, by means of linear stochastic estimation the mean flow structure is identified that is responsible for street-canyon ventilation for the sixth street and onwards. Moreover, it is shown that the vertical length scale of this structure increases with increasing aspect ratio of the obstacles in the canopy, while the streamwise length scale does not show a similar trend.

  1. Physics on the Smallest Scales: An Introduction to Minimal Length Phenomenology (United States)

    Sprenger, Martin; Nicolini, Piero; Bleicher, Marcus


    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…

  2. Evaluation of a Two-Length Scale Turbulence Model with Experiments on Shock-Driven Turbulent Mixing (United States)

    Carter, John; Gore, Rob; Ranjan, Devesh


    A new second moment turbulence model which uses separate transport and decay length scales is used to model the shock-driven instability. The ability of the model to capture the evolution of turbulence statistics and mixing is discussed. Evaluation is based on comparison to the Georgia Tech shock tube experiments. In the experiments a membraneless light-over-heavy interface is created. There is a long-wavelength perturbation which exists due to inclination of the entire shock tube. By limiting calculations to one dimension, there is not a geometric description of the incline, and the ability of the transport length scale alone to capture the effect of the long-wavelength perturbation is tested.

  3. Two-dimensional Length Extraction of Ballistic Target from ISAR Images Using a New Scaling Method by Affine Registration

    Directory of Open Access Journals (Sweden)

    Jin Guanghu


    Full Text Available The length of ballistic target is one of the most important features for target recognition. It can be extracted from ISAR Images. Unlike from the optical image, the length extraction from ISAR image has two difficulties. The first one is that it is hard to get the actual position of scattering centres by the traditional target extraction method. The second one is that the ISAR image’s cross scale is not known because of the target’s complex rotation. Here we propose two methods to solve these problems. Firstly, we use clustering method to get scattering centers. Secondly we propose to get cross scale of the ISAR images by affine registration. Experiments verified that our approach is realisable and has good performance.Defence Science Journal, Vol. 64, No. 5, September 2014, pp.458-463, DOI:

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

    Energy Technology Data Exchange (ETDEWEB)

    Hu, S. X.; Michel, D. T.; Edgell, D. H.; Froula, D. H.; Follett, R. K.; Goncharov, V. N.; Myatt, J. F.; Skupsky, S.; Yaakobi, B. [Laboratory for Laser Energetics, University of Rochester, 250 E. River Road, Rochester, New York 14623 (United States)


    Direct-drive-ignition designs with plastic CH ablators create plasmas of long density scale lengths (L{sub n} {>=} 500 {mu}m) at the quarter-critical density (N{sub qc}) 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 L{sub n} approaching {approx}400 {mu}m have been created; (2) the density scale length at N{sub qc} scales as L{sub n}({mu}m) Asymptotically-Equal-To (R{sub DPP} Multiplication-Sign I{sup 1/4}/2); and (3) the electron temperature T{sub e} at N{sub qc} scales as T{sub e}(keV) Asymptotically-Equal-To 0.95 Multiplication-Sign {radical}(I), with the incident intensity (I) measured in 10{sup 14} W/cm{sup 2} for plasmas created on both OMEGA and OMEGA EP configurations with different-sized (R{sub DPP}) 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 f{sub hot} is found to have a similar behavior for both configurations: a rapid growth [f{sub hot} Asymptotically-Equal-To f{sub c} Multiplication-Sign (G{sub c}/4){sup 6} for G{sub c} < 4] followed by a saturation of the form, f{sub hot} Asymptotically-Equal-To f{sub c} Multiplication-Sign (G{sub c}/4){sup 1.2} for G{sub c} {>=} 4, with the

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

    CERN Document Server

    Esteban, Juan Luis; Gómez-Rodríguez, Carlos


    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.

  6. The scaling of the minimum sum of edge lengths in uniformly random trees (United States)

    Esteban, Juan Luis; Ferrer-i-Cancho, Ramon; Gómez-Rodríguez, Carlos


    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.

  7. Human dynamics scaling characteristics for aerial inbound logistics operation (United States)

    Wang, Qing; Guo, Jin-Li


    In recent years, the study of power-law scaling characteristics of real-life networks has attracted much interest from scholars; it deviates from the Poisson process. In this paper, we take the whole process of aerial inbound operation in a logistics company as the empirical object. The main aim of this work is to study the statistical scaling characteristics of the task-restricted work patterns. We found that the statistical variables have the scaling characteristics of unimodal distribution with a power-law tail in five statistical distributions - that is to say, there obviously exists a peak in each distribution, the shape of the left part closes to a Poisson distribution, and the right part has a heavy-tailed scaling statistics. Furthermore, to our surprise, there is only one distribution where the right parts can be approximated by the power-law form with exponent α=1.50. Others are bigger than 1.50 (three of four are about 2.50, one of four is about 3.00). We then obtain two inferences based on these empirical results: first, the human behaviors probably both close to the Poisson statistics and power-law distributions on certain levels, and the human-computer interaction behaviors may be the most common in the logistics operational areas, even in the whole task-restricted work pattern areas. Second, the hypothesis in Vázquez et al. (2006) [A. Vázquez, J. G. Oliveira, Z. Dezsö, K.-I. Goh, I. Kondor, A.-L. Barabási. Modeling burst and heavy tails in human dynamics, Phys. Rev. E 73 (2006) 036127] is probably not sufficient; it claimed that human dynamics can be classified as two discrete university classes. There may be a new human dynamics mechanism that is different from the classical Barabási models.

  8. 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


    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.

  9. Flame Length (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...

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

    Directory of Open Access Journals (Sweden)

    Gunarif Taib


    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.

  11. Length-scale and strain rate-dependent mechanism of defect formation and fracture in carbon nanotubes under tensile loading (United States)

    Javvaji, Brahmanandam; Raha, S.; Mahapatra, D. Roy


    Electromagnetic and thermo-mechanical forces play a major role in nanotube-based materials and devices. Under high-energy electron transport or high current densities, carbon nanotubes fail via sequential fracture. The failure sequence is governed by certain length scale and flow of current. We report a unified phenomenological model derived from molecular dynamic simulation data, which successfully captures the important physics of the complex failure process. Length-scale and strain rate-dependent defect nucleation, growth, and fracture in single-walled carbon nanotubes with diameters in the range of 0.47 to 2.03 nm and length which is about 6.17 to 26.45 nm are simulated. Nanotubes with long length and small diameter show brittle fracture, while those with short length and large diameter show transition from ductile to brittle fracture. In short nanotubes with small diameters, we observe several structural transitions like Stone-Wales defect initiation, its propagation to larger void nucleation, formation of multiple chains of atoms, conversion to monatomic chain of atoms, and finally complete fracture of the carbon nanotube. Hybridization state of carbon-carbon bonds near the end cap evolves, leading to the formation of monatomic chain in short nanotubes with small diameter. Transition from ductile to brittle fracture is also observed when strain rate exceeds a critical value. A generalized analytical model of failure is established, which correlates the defect energy during the formation of atomic chain with aspect ratio of the nanotube and strain rate. Variation in the mechanical properties such as elastic modulus, tensile strength, and fracture strain with the size and strain rate shows important implications in mitigating force fields and ways to enhance the life of electronic devices and nanomaterial conversion via fracture in manufacturing.

  12. Predicting the roughness length of turbulent flows over landscapes with multi-scale microtopography


    Pelletier, Jon D.; Field, Jason P.


    The fully rough form of the law of the wall is commonly used to quantify velocity profiles and associated bed shear stresses in fluvial, aeolian, and coastal environments. A key parameter in this law is the roughness length, z0. Here we propose a predictive formula for z0 that uses the amplitude and slope of each wavelength of microtopography within a discrete-Fourier-transform-based approach. Computational fluid dynamics (CFD) modeling is used to quantify the effective z0 valu...

  13. 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


    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.

  14. Contact Mechanics of UV/Ozone-Treated PDMS by AFM and JKR Testing: Mechanical Performance from Nano- to Micrometer Length Scales

    NARCIS (Netherlands)

    Song, Jing; Tranchida, Davide; Vancso, G. Julius


    The Young’s modulus of cross-linked poly(dimethylsiloxane) (PDMS) surface was quantitatively investigated as a function of UV/ozone treatment time across different length scales. An AFM was used to probe PDMS surface mechanical properties at the nanometer length scale. The Young’s modulus of each sa

  15. Chain length distributions in linear polyaddition proceeding in nano-scale small volumes without mass transfer (United States)

    Szymanski, R.; Sosnowski, S.


    Computer simulations (Monte Carlo and numerical integration of differential equations) and theoretical analysis show that the statistical nature of polyaddition, both irreversible and reversible one, affects the way the macromolecules of different lengths are distributed among the small volume nano-reactors (droplets in this study) at any reaction time. The corresponding droplet distributions in respect to the number of reacting chains as well as the chain length distributions depend, for the given reaction time, on rate constants of polyaddition kp and depolymerization kd (reversible process), and the initial conditions: monomer concentration and the number of its molecules in a droplet. As a model reaction, a simple polyaddition process (M)1+(M)1 ⟶ ⟵ (M)2 , (M)i+(M)j ⟶ ⟵ (M)i+j was chosen, enabling to observe both kinetic and thermodynamic (apparent equilibrium constant) effects of a small number of reactant molecules in a droplet. The average rate constant of polymerization is lower than in a macroscopic system, depending on the average number of reactant molecules in a droplet. The apparent equilibrium constants of polymerization Ki j=[(M)i +j] ¯ /([(M)i] ¯ [(M)j] ¯ ) appear to depend on oligomer/polymer sizes as well as on the initial number of monomer molecules in a droplet. The corresponding equations, enabling prediction of the equilibrium conditions, were derived. All the analyzed effects are observed not only for ideally dispersed systems, i.e. with all droplets containing initially the same number of monomer (M)1 molecules, but also when initially the numbers of monomer molecules conform the Poisson distribution, expected for dispersions of reaction mixtures.

  16. The Sensitivity of Income Polarization - Time, length of accounting periods, equivalence scales, and income definitions

    DEFF Research Database (Denmark)

    Azhar, Hussain

    This study looks at polarization and its components’ sensitivity to assumptions about equivalence scales, income definition, ethical income distribution parameters, and the income accounting period. A representative sample of Danish individual incomes from 1984 to 2002 is utilised. Results show...... that polarization has increased over time, regardless of the applied measure, when the last part of the period is compared to the first part of the period. Primary causes being increased inequality (alienation) and faster income growth among high incomes relative to those in the middle of the distribution....... Increasing the accounting period confirms the reduction in inequality found for shorter periods, but polarization is virtually unchanged, because income group identification increases. Applying different equivalence scales does not change polarization ranking for different years, but identification ranks...

  17. Growth ring characteristics, specific gravity and fiber length of rapidly grown loblolly pine

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, F.W.; Burton, J.D.


    Intensive thinning, understory control, and green pruning of loblolly pine trees growing on a test area near Crossett, Arkansas, have produced trees with a diameter of 18.9 inches at breast heights in 35 years. Large increment borings extracted from experimental trees and control trees were examined for growth patterns and wood properties alterations related to growth rate differences. During some growth periods, radial growth of test trees was almost three times as great as radial growth of control trees. In the outer juvenile wood formed after the first thinning, growth rate differences were greatest between experimental trees. During the last 10 years of the study (mature wood zone), growth rate differences between treated and control trees were not as great, and there were no significant differences in latewood percentage or tracheid length. Specific gravity was not significantly influenced by growth rate differences in any growth zone. This result leads to the conclusion that trees can be rapidly grown without affecting specific gravity. (Refs. 19).

  18. Fine-scale local adaptation of weevil mouthpart length and camellia pericarp thickness: altitudinal gradient of a putative arms race. (United States)

    Toju, Hirokazu


    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.

  19. Hillslopes to Hollows to Channels: Identifying Process Transitions and Domains using Characteristic Scaling Relations (United States)

    Williams, K.; Locke, W. W.


    Headwater catchments are partitioned into hillslopes, unchanneled valleys (hollows), and channels. Low order (less than or equal to two) channels comprise most of the stream length in the drainage network so defining where hillslopes end and hollows begin, and where hollows end and channels begin, is important for calibration and verification of hydrologic runoff and sediment production modeling. We test the use of landscape scaling relations to detect flow regimes characteristic of diffusive, concentrated, and incisive runoff, and use these flow regimes as proxies for hillslope, hollow, and channeled landforms. We use LiDAR-derived digital elevation models (DEMs) of two pairs of headwater catchments in southwest and north-central Montana to develop scaling relations of flowpath length, total stream power, and contributing area. The catchment pairs contrast low versus high drainage density and north versus south aspect. Inflections in scaling relations of contributing area and flowpath length in a single basin (modified Hack's law) and contributing area and total stream power were used to identify hillslope and fluvial process domain transitions. In the modified Hack's law, inflections in the slope of the log-log power law are hypothesized to correspond to changes in flow regime used as proxies for hillslope, hollow, and channeled landforms. Similarly, rate of change of total stream power with contributing area is hypothesized to become constant and then decrease at the hillslope to fluvial domain transition. Power law scaling of frequency-magnitude plots of curvature and an aspect-related parameter were also tested as an indicator of the transition from scale-dependent hillslope length to the scale invariant fluvial domain. Curvature and aspect were calculated at each cell in spectrally filtered DEMs. Spectral filtering by fast Fourier and wavelet transforms enhances detection of fine-scale fluvial features by removing long wavelength topography. Using the

  20. 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


    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.

  1. Laser propagation measurements in long-scale-length underdense plasmas relevant to magnetized liner inertial fusion (United States)

    Harvey-Thompson, A. J.; Sefkow, A. B.; Wei, M. S.; Nagayama, T.; Campbell, E. M.; Blue, B. E.; Heeter, R. F.; Koning, J. M.; Peterson, K. J.; Schmitt, A.


    We report experimental results and simulations showing efficient laser energy coupling into plasmas at conditions relevant to the magnetized liner inertial fusion (MagLIF) concept. In MagLIF, to limit convergence and increase the hydrodynamic stability of the implosion, the fuel must be efficiently preheated. To determine the efficiency and physics of preheating by a laser, an Ar plasma with ne/nc r i t˜0.04 is irradiated by a multi-ns, multi-kJ, 0.35-μm, phase-plate-smoothed laser at spot-averaged intensities ranging from 1.0 ×1014 to 2.5 ×1014W /c m2 and pulse widths from 2 to 10 ns. Time-resolved x-ray images of the laser-heated plasma are compared to two-dimensional radiation-hydrodynamic simulations that show agreement with the propagating emission front, a comparison that constrains laser energy deposition to the plasma. The experiments show that long-pulse, modest-intensity (I =1.5 ×1014W /c m2 ) beams can efficiently couple energy (˜82 % of the incident energy) to MagLIF-relevant long-length (9.5 mm) underdense plasmas. The demonstrated heating efficiency is significantly higher than is thought to have been achieved in early integrated MagLIF experiments [A. B. Sefkow et al., Phys. Plasmas 21, 072711 (2014), 10.1063/1.4890298].

  2. Patchiness of ion-exchanged mica revealed by DNA binding dynamics at short length scales (United States)

    Billingsley, D. J.; Lee, A. J.; Johansson, N. A. B.; Walton, A.; Stanger, L.; Crampton, N.; Bonass, W. A.; Thomson, N. H.


    The binding of double-stranded (ds) DNA to mica can be controlled through ion-exchanging the mica with divalent cations. Measurements of the end-to-end distance of linear DNA molecules discriminate whether the binding mechanism occurs through 2D surface equilibration or kinetic trapping. A range of linear dsDNA fragments have been used to investigate length dependences of binding. Mica, ion-exchanged with Ni(II) usually gives rise to kinetically trapped DNA molecules, however, short linear fragments (ion-exchanged mica is heterogeneous, and contains patches or domains, separating different ionic species. These results correlate with imaging of dsDNA under aqueous buffer on Ni(II)-mica and indicate that binding domains are of the order of 100 nm in diameter. Shorter DNA fragments behave intermediate to the two extreme cases of 2D equilibration and kinetic trapping. Increasing the incubation time of Ni(II) on mica, from minutes to hours, brings the conformations of the shorter DNA fragments closer to the theoretical value for kinetic trapping, indicating that long timescale kinetics play a role in ion-exchange. X-ray photoelectron spectroscopy (XPS) was used to confirm that the relative abundance of Ni(II) ions on the mica surface increases with time. These findings can be used to enhance spatial control of binding of DNA to inorganic surfaces with a view to patterning high densities arrays.

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

    CERN Document Server

    Martinez-Tossas, Luis A


    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...

  4. Coupling Length Scales for Multiscale Atomistics-Continuum Simulations: Atomistically Induced Stress Distributions in Si/Si{sub 3}N

    Energy Technology Data Exchange (ETDEWEB)

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


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

  5. Characterization of length and velocity scales of free stream turbulence and investigation of their effects on surface heat transfer (United States)

    Yavuzkurt, Savash


    The main objective of this research is to address two important but unresolved problems: (1) the measurement of vertical and transverse length scales via space correlations for all Reynolds stress components and velocity-temperature correlations, both in the free stream and within the boundary layer using the existing triple and quad-wire probes; and (2) to relate the character of the free stream turbulence to the character of the turbulence within the boundary layer in order to determine the effect on surface heat transfer.

  6. 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.


    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.

  7. On determining characteristic length scales in pressure gradient turbulent boundary layers (United States)

    Vinuesa, Ricardo; Örlü, Ramis; Schlatter, Philipp


    In the present work we analyze three methods used to determine the edge of pressure gradient turbulent boundary layers: two based on composite profiles, the one by Chauhan et al. (Fluid Dyn. Res. 41:021401, 2009) and the one by Nickels (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. (Phys. Fluids 23:041702, 2011). The boundary layer developing over the suction side of a NACA4412 wing profile, extracted from a direct numerical simulation at Rec = 400,000, is used as the test case. We find that all the methods produce robust results with mild or moderate pressure gradients, but stronger pressure gradients (with 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. Therefore, the technique based on the diagnostic plot is a robust method to determine the boundary layer thickness (equivalent to δ99) and edge velocity in pressure gradient turbulent boundary layers.

  8. Characteristic Length Scales of Reactive Species in a Convective Boundary Layer

    NARCIS (Netherlands)

    Jonker, H.J.J.; Vilà-Guerau de Arellano, J.; Duynkerke, P.G.


    In this paper variance spectra of chemically active species in a dry convective boundary layer are studied by means of large-eddy simulations (LESs). The aim is to quantify the impact of chemistry on the spatial fluctuations in the concentration fields. The computational domain has a large aspect ra

  9. Application of nonlocal models to nano beams. Part II: Thickness length scale effect. (United States)

    Kim, Jun-Sik


    Applicability of nonlocal models to nano-beams is discussed in terms of the Eringen's nonlocal Euler-Bernoulli (EB) beam model. In literature, most work has taken the axial coordinate derivative in the Laplacian operator presented in nonlocal elasticity. This causes that the non-locality always makes the beam soften as compared to the local counterpart. In this paper, the thickness scale effect is solely considered to investigate if the nonlocal model can simulate stiffening effect. Taking the thickness derivative in the Laplacian operator leads to the presence of a surface stress state. The governing equation derived is compared to that of the EB model with the surface stress. The results obtained reveal that the nonlocality tends to decrease the bending moment stiffness whereas to increase the bending rigidity in the governing equation. This tendency also depends on the surface conditions.

  10. 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)


    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.

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

    Directory of Open Access Journals (Sweden)

    Chin-Guo Kuo


    Full Text Available 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 wt% and the anodization period was increased from 1 to 5 h, the TNT-array length was changed from 9.55 to 30.2 μm and the TNT-array diameter also increased. As NH4F concentration was 0.5 wt%, the prepared TNT arrays were also used to fabricate the dye-sensitized solar cells (DSSCs. We would show that the measured photovoltaic performance of the DSSCs was dependent on the TNT-array length.

  12. Diffusion-coupled molecular assembly: structuring of coordination polymers across multiple length scales. (United States)

    Hirai, Kenji; Reboul, Julien; Morone, Nobuhiro; Heuser, John E; Furukawa, Shuhei; Kitagawa, Susumu


    Porous coordination polymers (PCPs) are an intriguing class of molecular-based materials because of the designability of framework scaffolds, pore sizes and pore surface functionalities. Besides the structural designability at the molecular scale, the structuring of PCPs into mesoscopic/macroscopic morphologies has attracted much attention due to the significance for the practical applications. The structuring of PCPs at the mesoscopic/macroscopic scale has been so far demonstrated by the spatial localization of coordination reactions on the surface of templates or at the phase boundaries. However, these methodologies have never been applied to the fabrication of solid-solution or multivariate metal-organic frameworks (MOFs), in which multiple components are homogeneously mixed. Herein, we demonstrate the structuring of a box-type superstructure comprising of a solid-solution PCP by integrating a bidirectional diffusion of multiple organic ligands into molecular assembly. The parent crystals of [Zn2(ndc)2(bpy)]n were placed in the DMF solution of additional organic component of H2bdc, and the temperature was rapidly elevated up to 80 °C (ndc = 1,4-naphthalenedicarboxylate, bpy = 4,4'-bipyridyl, bdc = 1,4-benzenedicarboxylate). The dissolution of the parent crystals induced the outward diffusion of components; contrariwise, the accumulation of the other organic ligand of H2bdc induced the inward diffusion toward the surface of the parent crystals. This bidirectional diffusion of multiple components spatially localized the recrystallization at the surface of cuboid parent crystals; therefore, the nanocrystals of a solid-solution PCP ([Zn2(bdc)1.5(ndc)0.5(bpy)]n) were organized into a mesoscopic box superstructure. Furthermore, we demonstrated that the box superstructures enhanced the mass transfer kinetics for the separation of hydrocarbons.

  13. Numerical study of the scaling of the maximum kinetic energy per unit length for imploding Z-pinch liner

    Institute of Scientific and Technical Information of China (English)

    Zeng Zheng-Zhong; Qiu Ai-Ci


    Numerical computation based on a zero-dimensional thin-plasma-shell model has been carried out to study the scaling of the maximum kinetic energy per unit length, the current amplitude and the compression ratio for the imploding Z-pinch liner driven by peaked current pulses. A dimensionless scaling constant of 0.9 with an error less than 10% is extracted at the optimal choice of the current and liner parameters. Deviation of the chosen experimental parameter from the optimal exerts a minor influence on the kinetic energy for wider-shaped and slower-decaying pulses, but the influence becomes significant for narrower-shaped and faster-decaying pulses. The computation is in reasonable agreement with experimental data from the Z, Saturn, Blackjack 5 and Qiangguang-I liners.

  14. Critical points, phase transitions and water-like anomalies for an isotropic two length scale potential with increasing attractive well (United States)

    Pinheiro, L.; Furlan, A. P.; Krott, L. B.; Diehl, A.; Barbosa, M. C.


    Molecular Dynamic and Monte Carlo studies are performed in a system of particles interacting through core-softened (CS) potential, composed by two length scales: a repulsive shoulder at short distances and the another a variable scale, that can be repulsive or strongly attractive depending on the parameters used. The system show water-like anomalous behavior. The density, diffusion and structural anomalous regions in the pressure versus temperature phase diagram shrink in pressure as the system becomes more attractive. The transition appears with the increase of the attraction well. We found that the liquid-gas phase transition is Ising-like for all the CS potentials and its critical temperature increases with the increase of the attraction. No Ising-like behavior for the liquid-liquid phase transition was detected in the Monte Carlo simulations what might be due to the presence of stable amorphous phases.

  15. Delineating tectonic units beneath the Donbas Fold Belt using scale lengths estimated from DOBRE 2000/2001 deep reflection data (United States)

    Carpentier, S. F. A.; Roy-Chowdhury, K.; Stephenson, R. A.; Stovba, S.


    A novel statistical analysis, which augments conventional interpretation of deep seismic reflection/refraction data, is applied to the DOBRE 2000/2001 reflection profile. The goal is to improve delineation of the lithosphere in terms of lithotectonic units and to compare these to existing interpretations. After a successful validation of the method using synthetic data, stochastic parameters estimated from windowed average lateral autocorrelations in the DOBRE data are compiled in a two-dimensional profile of von Karman-type causative reflectivity. These estimates in terms of lateral correlation lengths and power law exponents are accompanied by associated uncertainties. Given its low uncertainties, the lateral correlation length ax turns out to be a robust delineator. The profile of ax reveals systematic spatial variations in the lithospheric fabric below the Donbas Fold Belt. As in earlier interpretations based upon conventional processing of reflection/refraction data, both the sedimentary basin and Moho discontinuity stand out clearly, as well as a region indicating massive vertical intrusion in the crust from upper mantle sills and ultramafic underplating of the lower crust. Notable differences with conventional interpretations include the number and extent of supra-Moho rift pillow structures, the lack of imaging a crust-cutting dislocation feature and a laterally disturbed uppermost mantle. Von Karman lateral correlation length provides new independent information at a scale between velocity models from wide-angle reflection/refraction data and line drawings from near vertical reflections and provides new insights and understanding of lithospheric evolution.

  16. Singular value decomposition of genome-scale mRNA lengths distribution reveals asymmetry in RNA gel electrophoresis band broadening. (United States)

    Alter, Orly; Golub, Gene H


    We describe the singular value decomposition (SVD) of yeast genome-scale mRNA lengths distribution data measured by DNA microarrays. SVD uncovers in the mRNA abundance levels data matrix of genes x arrays, i.e., electrophoretic gel migration lengths or mRNA lengths, mathematically unique decorrelated and decoupled "eigengenes." The eigengenes are the eigenvectors of the arrays x arrays correlation matrix, with the corresponding series of eigenvalues proportional to the series of the "fractions of eigen abundance." Each fraction of eigen abundance indicates the significance of the corresponding eigengene relative to all others. We show that the eigengenes fit "asymmetric Hermite functions," a generalization of the eigenfunctions of the quantum harmonic oscillator and the integral transform which kernel is a generalized coherent state. The fractions of eigen abundance fit a geometric series as do the eigenvalues of the integral transform which kernel is a generalized coherent state. The "asymmetric generalized coherent state" models the measured data, where the profiles of mRNA abundance levels of most genes as well as the distribution of the peaks of these profiles fit asymmetric Gaussians. We hypothesize that the asymmetry in the distribution of the peaks of the profiles is due to two competing evolutionary forces. We show that the asymmetry in the profiles of the genes might be due to a previously unknown asymmetry in the gel electrophoresis thermal broadening of a moving, rather than a stationary, band of RNA molecules.

  17. Molecular density functional theory of water describing hydrophobicity at short and long length scales. (United States)

    Jeanmairet, Guillaume; Levesque, Maximilien; Borgis, Daniel


    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.

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

    Directory of Open Access Journals (Sweden)

    A. J. G. Nurser


    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.

  19. On the coherence length of large-scale peculiar velocities and gravitational clustering

    Energy Technology Data Exchange (ETDEWEB)

    Kashlinsky, A. (National Radio Astronomy Observatory, Charlottesville, VA (USA); Queen Mary College, London (England))


    If the large-scale structure in the universe is formed by gravitational clustering of less than 0 density fluctuations, the correlation function of massive objects/clusters of the clustering hierarchy would be increased over the underlying mass autocorrelation function. This means that if light traces mass, the peculiar gravitational field on the average would be stronger when measured by galaxies associated with such clusters. This in turn would lead to larger rms peculiar velocities deduced from the motions of such samples. Ellipticals are known to populate preferentially dense regions/(rich) clusters, and it is, therefore, suggested that this mechanism is responsible for the large peculiar motions observed recently by the Seven Samurai in a sample of elliptical galaxies. On the assumption that light traces mass, these and the cluster-cluster correlation function results are consistent with gravitational clustering of n of about -1 fluctuations in Omega of about 0.2 universe. It is further shown that according to the gravitational clustering theory, galaxies selected preferentially from poor groups should exhibit small rms peculiar velocities. 21 refs.

  20. Planar Laser-Plasma Interaction Experiments at Direct-Drive Ignition-Relevant Scale Lengths at the National Ignition Facility (United States)

    Rosenberg, M. J.; Solodov, A. A.; Seka, W.; Myatt, J. F.; Regan, S. P.; Hohenberger, M.; Epstein, R.; Froula, D. H.; Radha, P. B.; Michel, P. A.; Moody, J. D.; Masse, L.; Goyon, C.; Turnbull, D. P.; Barrios, M. A.; Bates, J. W.; Schmitt, A. J.


    The first experiments at the National Ignition Facility to probe laser-plasma interactions and the hot electron production at scale lengths relevant to direct-drive ignition are reported. The irradiation on one side of planar CH foils generated a plasma at the quarter-critical surface with predicted density scale lengths of Ln 600 μm, measured electron temperatures of Te 3.5 to 4.0 keV, and overlapped laser intensities of I 6 to 15 ×1014W/cm2. Optical emission from stimulated Raman scattering (SRS) and at ω/2 are correlated with the time-dependent hard x-ray signal. The fraction of laser energy converted to hot electrons increased from 0.5 % to 2.3 % as the laser intensity increased from 6 to 15 ×1014W/cm2, while the hot electron temperature was nearly constant around 40 to 50 keV. Only a sharp red-shifted feature is observed around ω/2, and both refracted and sidescattered SRS are detected, suggesting that multibeam SRS contributes to, and may even dominate, hot-electron production. These results imply a diminished presence of two-plasmon decay relative to SRS at these conditions, which has implications for hot-electron preheat mitigation strategies for direct-drive ignition. This work is supported by the DOE NNSA under Award Number DE-NA0001944.

  1. Validation of a Scaling Law for the Coronal Magnetic Field Strengths and Loop Lengths of Solar and Stellar Flares

    CERN Document Server

    Namekata, Kosuke; Watanabe, Kyoko; Asai, Ayumi; Shibata, Kazunari


    Shibata & Yokoyama (1999, 2002) proposed a method of estimating the coronal magnetic field strengths ($B$) and magnetic loop lengths ($L$) of solar and stellar flares, on the basis of magnetohydrodynamic simulations of the magnetic reconnection model. Using the scaling law provided by Shibata & Yokoyama (1999, 2002), $B$ and $L$ are obtained as functions of the emission measure ($EM=n^2L^3$) and temperature ($T$) at the flare peak. Here, $n$ is the coronal electron density of the flares. This scaling law enables the estimation of $B$ and $L$ for unresolved stellar flares from the observable physical quantities $EM$ and $T$, which is helpful for studying stellar surface activities. To apply this scaling law to stellar flares, we discuss its validity for spatially resolved solar flares. $EM$ and $T$ were calculated from GOES soft X-ray flux data, and $B$ and $L$ are theoretically estimated using the scaling law. For the same flare events, $B$ and $L$ were also observationally estimated with images taken...

  2. From divots to swales: Hillslope sediment transport across divers length scales (United States)

    Furbish, David Jon; Haff, Peter K.


    In soil-mantled steeplands, soil motions associated with creep, ravel, rain splash, soil slips, tree throw, and rodent activity are patchy and intermittent and involve widely varying travel distances. To describe the collective effect of these motions, we formulate a nonlocal expression for the soil flux. This probabilistic formulation involves upslope and downslope convolutions of land surface geometry to characterize motions in both directions, notably accommodating the bidirectional dispersal of material on gentle slopes as well as mostly downslope dispersal on steeper slopes, and it distinguishes between the mobilization of soil material and the effect of surface slope in giving a downslope bias to the dispersal of mobilized material. The formulation separates dispersal associated with intermittent surface motions from the slower bulk behavior associated with small-scale bioturbation and similar dilational processes operating mostly within the soil column. With a uniform rate of mobilization of soil material, the nearly parabolic form of a hillslope profile at steady state resembles a diffusive behavior. With a slope-dependent rate of mobilization, the steady state hillslope profile takes on a nonparabolic form where land surface elevation varies with downslope distance x as xa with a ˜ 3/2, consistent with field observations and where the flux increases nonlinearly with increasing slope. The convolution description of the soil flux, when substituted into a suitable expression of conservation, yields a nonlinear Fokker-Planck equation and can be mapped to discrete particle models of hillslope behavior and descriptions of soil-grain transport by rain splash as a stochastic advection-dispersion process.

  3. 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.


    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.

  4. Studying Soft-matter and Biological Systems over a Wide Length-scale from Nanometer and Micrometer Sizes at the Small-angle Neutron Diffractometer KWS-2 (United States)

    Radulescu, Aurel; Szekely, Noemi Kinga; Appavou, Marie-Sousai; Pipich, Vitaliy; Kohnke, Thomas; Ossovyi, Vladimir; Staringer, Simon; Schneider, Gerald J.; Amann, Matthias; Zhang-Haagen, Bo; Brandl, Georg; Drochner, Matthias; Engels, Ralf; Hanslik, Romuald; Kemmerling, Günter


    The KWS-2 SANS diffractometer is dedicated to the investigation of soft matter and biophysical systems covering a wide length scale, from nm to µm. The instrument is optimized for the exploration of the wide momentum transfer Q range between 1x10-4 and 0.5 Å-1 by combining classical pinhole, focusing (with lenses), and time-of-flight (with chopper) methods, while simultaneously providing high-neutron intensities with an adjustable resolution. Because of its ability to adjust the intensity and the resolution within wide limits during the experiment, combined with the possibility to equip specific sample environments and ancillary devices, the KWS-2 shows a high versatility in addressing the broad range of structural and morphological studies in the field. Equilibrium structures can be studied in static measurements, while dynamic and kinetic processes can be investigated over time scales between minutes to tens of milliseconds with time-resolved approaches. Typical systems that are investigated with the KWS-2 cover the range from complex, hierarchical systems that exhibit multiple structural levels (e.g., gels, networks, or macro-aggregates) to small and poorly-scattering systems (e.g., single polymers or proteins in solution). The recent upgrade of the detection system, which enables the detection of count rates in the MHz range, opens new opportunities to study even very small biological morphologies in buffer solution with weak scattering signals close to the buffer scattering level at high Q. In this paper, we provide a protocol to investigate samples with characteristic size levels spanning a wide length scale and exhibiting ordering in the mesoscale structure using KWS-2. We present in detail how to use the multiple working modes that are offered by the instrument and the level of performance that is achieved. PMID:28060296

  5. Validation of a scaling law for the coronal magnetic field strength and loop length of solar and stellar flares (United States)

    Namekata, Kosuke; Sakaue, Takahito; Watanabe, Kyoko; Asai, Ayumi; Shibata, Kazunari


    Shibata and Yokoyama (1999, ApJ, 526, L49; 2002, ApJ, 577, 422) proposed a method of estimating the coronal magnetic field strength (B) and magnetic loop length (L) of solar and stellar flares, on the basis of magnetohydrodynamic simulations of the magnetic reconnection model. Using the scaling law provided by Shibata and Yokoyama (1999, ApJ, 526, L49; 2002, ApJ, 577, 422), we obtain B and L as functions of the emission measure (EM = n2L3) and temperature (T) at the flare peak. Here, n is the coronal electron density of the flares. This scaling law enables the estimation of B and L for unresolved stellar flares from the observable physical quantities EM and T, which is helpful for studying stellar surface activities. To apply this scaling law to stellar flares, we discuss its validity for spatially resolved solar flares. Quantities EM and T are calculated from GOES (Geostationary Operational Environmental Satellite) soft X-ray flux data, and B and L are theoretically estimated using the scaling law. For the same flare events, B and L were also observationally estimated with images taken by the Solar Dynamics Observatory (SDO)/Helioseismic and Magnetic Imager (HMI) Magnetogram and Atmospheric Imaging Assembly (AIA) 94 Å pass band. As expected, a positive correlation was found between the theoretically and observationally estimated values. We interpret this result as indirect evidence that flares are caused by magnetic reconnection. Moreover, this analysis makes us confident about the validity of applying this scaling law to stellar flares as well as solar flares.

  6. 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


    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 .

  7. Estimation of length scale of RS II-$p$ braneworld model through perturbations in Helium's atom ground state energy

    CERN Document Server

    Garrido, Nephtali


    We put to the test an effective three-dimensional electrostatic potential, obtained effectively by considering an electrostatic source inside a (5+$p$)-dimensional braneworld scenario with $p$ compact and one infinite spacial extra dimensions in the RS II-$p$ model, for $p=1$ and $p=2$. This potential is regular at the source and matches the standard Coulomb potential outside a neighborhood. We use variational and perturbative approximation methods to calculate corrections to the ground energy of the Helium atom modified by this potential, by making use of a 6 and 39-parameter trial wave function of Hylleraas type for the ground state. These corrections to the ground-state energy are compared with experimental data for Helium atom in order to set bounds for the extra dimensions length scale. We find that these bounds are less restrictive than the ones obtained by Morales et. al. through a calculation using the Lamb shift in Hydrogen.

  8. First-principles computation of random-pinning glass transition, glass cooperative length scales, and numerical comparisons (United States)

    Cammarota, Chiara; Seoane, Beatriz


    As a guideline for experimental tests of the ideal glass transition (random-pinning glass transition, RPGT) that shall be induced in a system by randomly pinning particles, we performed first-principle computations within the hypernetted chain approximation and numerical simulations of a hard-sphere model of a glass former. We obtain confirmation of the expected enhancement of glassy behavior under the procedure of random pinning. We present the analytical phase diagram as a function of c and of the packing fraction ϕ , showing a line of RPGT ending in a critical point. We also obtain microscopic results on cooperative length scales characterizing medium-range amorphous order in hard-sphere glasses and indirect quantitative information on a key thermodynamic quantity defined in proximity to ideal glass transitions, the amorphous surface tension. Finally, we present numerical results of pair correlation functions able to differentiate the liquid and the glass phases, as predicted by the analytic computations.

  9. Predicting permeability of regular tissue engineering scaffolds: scaling analysis of pore architecture, scaffold length, and fluid flow rate effects. (United States)

    Rahbari, A; Montazerian, H; Davoodi, E; Homayoonfar, S


    The main aim of this research is to numerically obtain the permeability coefficient in the cylindrical scaffolds. For this purpose, a mathematical analysis was performed to derive an equation for desired porosity in terms of morphological parameters. Then, the considered cylindrical geometries were modeled and the permeability coefficient was calculated according to the velocity and pressure drop values based on the Darcy's law. In order to validate the accuracy of the present numerical solution, the obtained permeability coefficient was compared with the published experimental data. It was observed that this model can predict permeability with the utmost accuracy. Then, the effect of geometrical parameters including porosity, scaffold pore structure, unit cell size, and length of the scaffolds as well as entrance mass flow rate on the permeability of porous structures was studied. Furthermore, a parametric study with scaling laws analysis of sample length and mass flow rate effects on the permeability showed good fit to the obtained data. It can be concluded that the sensitivity of permeability is more noticeable at higher porosities. The present approach can be used to characterize and optimize the scaffold microstructure due to the necessity of cell growth and transferring considerations.

  10. Sizing Up the Milky Way: A Bayesian Mixture Model Meta-analysis of Photometric Scale Length Measurements (United States)

    Licquia, Timothy C.; Newman, Jeffrey A.


    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 are often statistically incompatible with one another. Here, we perform a Bayesian meta-analysis to determine an improved, aggregate estimate for L d , utilizing a mixture-model approach to account 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 employ 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 the literature; these involve a broad assortment of observational data sets, MW models and assumptions, and methodologies, all tabulated herein. Analyzing the visible and infrared measurements separately yields estimates for L d of {2.71}-0.20+0.22 kpc and {2.51}-0.13+0.15 kpc, respectively, whereas considering them all combined yields 2.64 ± 0.13 kpc. The ratio between the visible and infrared scale lengths determined here is very similar to that measured in external spiral galaxies. We use these results to update the model of the Galactic disk from our previous work, constraining its stellar mass to be {4.8}-1.1+1.5× {10}10 M ⊙, and the MW’s total stellar mass to be {5.7}-1.1+1.5× {10}10 M ⊙.

  11. Scaling Dimensions of Nitrogen Adsorption Characteristics in Modulated Mesoporous Aluminophosphates (United States)

    Petrakis; Pasxalidis; Theocharis; Hudson; Pomonis


    Mesoporous alumina-aluminophosphates (MAAP) of the general formula Al100PXM20 (M = Al, Fe, Cr, and Ni and X = 0, 4.5, 9, 18, 36, 72, and 144) were tested for their pore size distribution by nitrogen adsorption. The distribution of pore size can be modified by the addition of phosphorus. The scaling or fractal dimensions (DS) of the adsorption characteristics in the pores, calculated from the plots of the log of the corresponding cumulative BJH desorption pores surface area versus the log of the corresponding pore size, indicate that for low values of P/P0, the adsorption proceeds in a two-dimensional manner, independently of the pore size distribution (p.s.d.). However, at high P/P0 values and narrow p.s.d. DS >/= 3, while at wide p.s.d. DS > 3. At medium P/P0 values the DS values obtained were found as high as 10 for narrow pore size distribution and decrease as the p.s.d. becomes wide by the addition of phosphorus. These phenomena are related to the supercritical condensation of nitrogen in the pores of MAAP.

  12. Large scale full-length cDNA sequencing reveals a unique genomic landscape in a lepidopteran model insect, Bombyx mori. (United States)

    Suetsugu, Yoshitaka; Futahashi, Ryo; Kanamori, Hiroyuki; Kadono-Okuda, Keiko; Sasanuma, Shun-ichi; Narukawa, Junko; Ajimura, Masahiro; Jouraku, Akiya; Namiki, Nobukazu; Shimomura, Michihiko; Sezutsu, Hideki; Osanai-Futahashi, Mizuko; Suzuki, Masataka G; Daimon, Takaaki; Shinoda, Tetsuro; Taniai, Kiyoko; Asaoka, Kiyoshi; Niwa, Ryusuke; Kawaoka, Shinpei; Katsuma, Susumu; Tamura, Toshiki; Noda, Hiroaki; Kasahara, Masahiro; Sugano, Sumio; Suzuki, Yutaka; Fujiwara, Haruhiko; Kataoka, Hiroshi; Arunkumar, Kallare P; Tomar, Archana; Nagaraju, Javaregowda; Goldsmith, Marian R; Feng, Qili; Xia, Qingyou; Yamamoto, Kimiko; Shimada, Toru; Mita, Kazuei


    The establishment of a complete genomic sequence of silkworm, the model species of Lepidoptera, laid a foundation for its functional genomics. A more complete annotation of the genome will benefit functional and comparative studies and accelerate extensive industrial applications for this insect. To realize these goals, we embarked upon a large-scale full-length cDNA collection from 21 full-length cDNA libraries derived from 14 tissues of the domesticated silkworm and performed full sequencing by primer walking for 11,104 full-length cDNAs. The large average intron size was 1904 bp, resulting from a high accumulation of transposons. Using gene models predicted by GLEAN and published mRNAs, we identified 16,823 gene loci on the silkworm genome assembly. Orthology analysis of 153 species, including 11 insects, revealed that among three Lepidoptera including Monarch and Heliconius butterflies, the 403 largest silkworm-specific genes were composed mainly of protective immunity, hormone-related, and characteristic structural proteins. Analysis of testis-/ovary-specific genes revealed distinctive features of sexual dimorphism, including depletion of ovary-specific genes on the Z chromosome in contrast to an enrichment of testis-specific genes. More than 40% of genes expressed in specific tissues mapped in tissue-specific chromosomal clusters. The newly obtained FL-cDNA sequences enabled us to annotate the genome of this lepidopteran model insect more accurately, enhancing genomic and functional studies of Lepidoptera and comparative analyses with other insect orders, and yielding new insights into the evolution and organization of lepidopteran-specific genes.

  13. Psychometric Characteristics of the Professor-Student Rapport Scale (United States)

    Ryan, Rebecca G.; Wilson, Janie H.; Pugh, James L.


    In this study, the authors assessed the psychometric properties of the Professor-Student Rapport Scale, the first scale to measure professor-student rapport. The scale was found to have adequate test-retest and internal-consistency reliability. In addition to these findings, measures used to determine convergent validity included the Working…

  14. Psychometric Characteristics of the UCLA Loneliness Scale: A Study with Iranian College Students. (United States)

    Hojat, Mohammadreza


    The psychometric characteristics of the revised UCLA Loneliness Scale in Iranian groups correlated significantly with measures of other conceptually-related variables such as depression, anxiety, and neuroticism. Factorial structure supported the multidimensionality of the scale. (Author/PN)

  15. Allometric and temporal scaling of movement characteristics in Galapagos tortoises. (United States)

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


    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

  16. Allometric and temporal scaling of movement characteristics in Galapagos tortoises (United States)

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


    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

  17. 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)


    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.

  18. [Analysis of the molecular characteristics and cloning of full-length coding sequence of interleukin-2 in tree shrews]. (United States)

    Huang, Xiao-Yan; Li, Ming-Li; Xu, Juan; Gao, Yue-Dong; Wang, Wen-Guang; Yin, An-Guo; Li, Xiao-Fei; Sun, Xiao-Mei; Xia, Xue-Shan; Dai, Jie-Jie


    While the tree shrew (Tupaia belangeri chinensis) is an excellent animal model for studying the mechanisms of human diseases, but few studies examine interleukin-2 (IL-2), an important immune factor in disease model evaluation. In this study, a 465 bp of the full-length IL-2 cDNA encoding sequence was cloned from the RNA of tree shrew spleen lymphocytes, which were then cultivated and stimulated with ConA (concanavalin). Clustal W 2.0 was used to compare and analyze the sequence and molecular characteristics, and establish the similarity of the overall structure of IL-2 between tree shrews and other mammals. The homology of the IL-2 nucleotide sequence between tree shrews and humans was 93%, and the amino acid homology was 80%. The phylogenetic tree results, derived through the Neighbour-Joining method using MEGA5.0, indicated a close genetic relationship between tree shrews, Homo sapiens, and Macaca mulatta. The three-dimensional structure analysis showed that the surface charges in most regions of tree shrew IL-2 were similar to between tree shrews and humans; however, the N-glycosylation sites and local structures were different, which may affect antibody binding. These results provide a fundamental basis for the future study of IL-2 monoclonal antibody in tree shrews, thereby improving their utility as a model.

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

    Directory of Open Access Journals (Sweden)

    Z. Yu


    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.

  20. Geometry- and Length Scale-Dependent Deformation and Recovery on Micro- and Nanopatterned Shape Memory Polymer Surfaces (United States)

    Lee, Wei Li; Low, Hong Yee


    Micro- and nanoscale surface textures, when optimally designed, present a unique approach to improve surface functionalities. Coupling surface texture with shape memory polymers may generate reversibly tuneable surface properties. A shape memory polyetherurethane is used to prepare various surface textures including 2 μm- and 200 nm-gratings, 250 nm-pillars and 200 nm-holes. The mechanical deformation via stretching and recovery of the surface texture are investigated as a function of length scales and shapes. Results show the 200 nm-grating exhibiting more deformation than 2 μm-grating. Grating imparts anisotropic and surface area-to-volume effects, causing different degree of deformation between gratings and pillars under the same applied macroscopic strain. Full distribution of stress within the film causes the holes to deform more substantially than the pillars. In the recovery study, unlike a nearly complete recovery for the gratings after 10 transformation cycles, the high contribution of surface energy impedes the recovery of holes and pillars. The surface textures are shown to perform a switchable wetting function. This study provides insights into how geometric features of shape memory surface patterns can be designed to modulate the shape programming and recovery, and how the control of reversibly deformable surface textures can be applied to transfer microdroplets.

  1. 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


    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.

  2. Detection of different-time-scale signals in the length of day variation based on EEMD analysis technique

    Institute of Scientific and Technical Information of China (English)

    Wenbin Shen; Cunchao Peng


    Scientists pay great attention to different-time-scale signals in the length of day (LOD)variations ALOD,which provide signatures of the Earth's interior structure,couplings among different layers,and potential excitations of ocean and atmosphere.In this study,based on the ensemble empirical mode decomposition (EEMD),we analyzed the latest time series of ALOD data spanning from January 1962 to March 2015.We observed the signals with periods and amplitudes of about 0.5 month and 0.19 ms,1.0 month and 0.19 ms,0.5 yr and 0.22 ms,1.0 yr and 0.18 ms,2.28 yr and 0.03 ms,5.48 yr and 0.05 ms,respectively,in coincidence with the results of predecessors.In addition,some signals that were previously not definitely observed by predecessors were detected in this study,with periods and amplitudes of 9.13 d and 0.12 ms,13.69 yr and 0.10 ms,respectively.The mechanisms of the LOD fluctuations of these two signals are still open.

  3. The PML gene is linked to a megabase-scale insertion/deletion restriction fragment length polymorphism

    Energy Technology Data Exchange (ETDEWEB)

    Goy, A.; Xiao, Y.H.; Passalaris, T. [Memorial Sloan-Kettering Cancer Center, New York, NY (United States)] [and others


    The PML gene located on chromosome band 15q22 is involved with the RAR{alpha} locus (17q21) in a balanced reciprocal translocation uniquely observed in acute promyelocytic leukemia. Physical mapping studies by pulsed-field gel electrophoresis revealed that the PML gene is flanked by two CpG islands that are separated by a variable distance in normal individuals. Several lines of evidence demonstrate that this is the consequence of a large insertion/deletion polymorphism linked to the PML locus: (1) overlapping fragments obtained with a variety of rare-cutting restriction enzymes demonstrated the same variability in distance between the flanking CpG islands; (2) mapping with restriction enzymes insensitive to CpG methylation confirmed that the findings were not a consequence of variable methylation of CpG dinucleotides; (3) the polymorphism followed a Mendelian inheritance pattern. This polymorphism is localized 3{prime} to the PML locus. There are five common alleles, described on the basis of BssHII fragments, ranging from 220 to 350 kb with increments of approximately 30 kb between alleles. Both heterozygous (61%) and homozygous (391%) patterns were observed in normal individuals. Mega-base-scale insertion/deletion restriction fragment length polymorphisms are very rare and have been described initially in the context of multigene families. Such structures have been also reported as likely regions of genetic instability. High-resolution restriction mapping of this particular structure linked to the PML locus is underway. 47 refs., 4 figs., 1 tab.

  4. Seeing with the nano-eye: accessing structure, function, and dynamics of matter on its natural length and time scales (United States)

    Raschke, Markus


    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.

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

    Directory of Open Access Journals (Sweden)

    Z. Yu


    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.

  6. Optical design and multi-length-scale scanning spectro-microscopy possibilities at the Nanoscopium beamline of Synchrotron Soleil. (United States)

    Somogyi, Andrea; Medjoubi, Kadda; Baranton, Gil; Le Roux, Vincent; Ribbens, Marc; Polack, François; Philippot, Pascal; Samama, Jean Pierre


    The Nanoscopium 155 m-long beamline of Synchrotron Soleil is dedicated to scanning hard X-ray nanoprobe techniques. Nanoscopium aims to reach ≤100 nm resolution in the 5-20 keV energy range for routine user experiments. The beamline design tackles the tight stability requirements of such a scanning nanoprobe by creating an overfilled secondary source, implementing all horizontally reflecting main beamline optics, applying high mechanical stability equipment and constructing a dedicated high-stability building envelope. Multi-technique scanning imaging and tomography including X-ray fluorescence spectrometry and spectro-microscopy, absorption, differential phase and dark-field contrasts are implemented at the beamline in order to provide simultaneous information on the elemental distribution, speciation and sample morphology. This paper describes the optical concept and the first measured performance of the Nanoscopium beamline followed by the hierarchical length-scale multi-technique imaging experiments performed with dwell times down to 3 ms per pixel.

  7. Soft x-ray microscopy - a powerful analytical tool to image magnetism down to fundamental length and times scales

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Peter


    The magnetic properties of low dimensional solid state matter is of the utmost interest both scientifically as well as technologically. In addition to the charge of the electron which is the base for current electronics, by taking into account the spin degree of freedom in future spintronics applications open a new avenue. Progress towards a better physical understanding of the mechanism and principles involved as well as potential applications of nanomagnetic devices can only be achieved with advanced analytical tools. Soft X-ray microscopy providing a spatial resolution towards 10nm, a time resolution currently in the sub-ns regime and inherent elemental sensitivity is a very promising technique for that. This article reviews the recent achievements of magnetic soft X-ray microscopy by selected examples of spin torque phenomena, stochastical behavior on the nanoscale and spin dynamics in magnetic nanopatterns. The future potential with regard to addressing fundamental magnetic length and time scales, e.g. imaging fsec spin dynamics at upcoming X-ray sources is pointed out.

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

    Institute of Scientific and Technical Information of China (English)


    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.

  9. Stainless steel corrosion scale formed in reclaimed water: Characteristics, model for scale growth and metal element release. (United States)

    Cui, Yong; Liu, Shuming; Smith, Kate; Hu, Hongying; Tang, Fusheng; Li, Yuhong; Yu, Kanghua


    Stainless steels generally have extremely good corrosion resistance, but are still susceptible to pitting corrosion. As a result, corrosion scales can form on the surface of stainless steel after extended exposure to aggressive aqueous environments. Corrosion scales play an important role in affecting water quality. These research results showed that interior regions of stainless steel corrosion scales have a high percentage of chromium phases. We reveal the morphology, micro-structure and physicochemical characteristics of stainless steel corrosion scales. Stainless steel corrosion scale is identified as a podiform chromite deposit according to these characteristics, which is unlike deposit formed during iron corrosion. A conceptual model to explain the formation and growth of stainless steel corrosion scale is proposed based on its composition and structure. The scale growth process involves pitting corrosion on the stainless steel surface and the consecutive generation and homogeneous deposition of corrosion products, which is governed by a series of chemical and electrochemical reactions. This model shows the role of corrosion scales in the mechanism of iron and chromium release from pitting corroded stainless steel materials. The formation of corrosion scale is strongly related to water quality parameters. The presence of HClO results in higher ferric content inside the scales. Cl(-) and SO4(2-) ions in reclaimed water play an important role in corrosion pitting of stainless steel and promote the formation of scales.

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

    Energy Technology Data Exchange (ETDEWEB)

    Gaedke, Achim


    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

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

    KAUST Repository

    Kim, Hyoung-Moon


    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.

  12. 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


    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.

  13. 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


    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.

  14. Fluid mechanics of dynamic stall. II - Prediction of full scale characteristics (United States)

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


    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.

  15. Length-Scale-Dependent Phase Transformation of LiFePO4 : An In situ and Operando Study Using Micro-Raman Spectroscopy and XRD. (United States)

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


    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.

  16. Small-scale, homelike facilities versus regular psychogeriatric nursing home wards: a cross-sectional study into residents' characteristics

    Directory of Open Access Journals (Sweden)

    Kempen Gertrudis IJM


    Full Text Available Abstract Background Nursing home care for people with dementia is increasingly organized in small-scale and homelike care settings, in which normal daily life is emphasized. Despite this increase, relatively little is known about residents' characteristics and whether these differ from residents in traditional nursing homes. This study explored and compared characteristics of residents with dementia living in small-scale, homelike facilities and regular psychogeriatric wards in nursing homes, focusing on functional status and cognition. Methods A cross-sectional study was conducted, including 769 residents with dementia requiring an intensive level of nursing home care: 586 from regular psychogeriatric wards and 183 residents from small-scale living facilities. Functional status and cognition were assessed using two subscales from the Resident Assessment Instrument Minimum Data Set (RAI-MDS: the Activities of Daily Living-Hierarchy scale (ADL-H and the Cognitive Performance Scale (CPS. In addition, care dependency was measured using Dutch Care Severity Packages (DCSP. Finally, gender, age, living condition prior to admission and length of stay were recorded. Descriptive analyses, including independent samples t- tests and chi-square tests, were used. To analyze data in more detail, multivariate logistic regression analyses were performed. Results Residents living in small-scale, homelike facilities had a significantly higher functional status and cognitive performance compared with residents in regular psychogeriatric wards. In addition, they had a shorter length of stay, were less frequently admitted from home and were more often female than residents in regular wards. No differences were found in age and care dependency. While controlling for demographic variables, the association between dementia care setting and functional status and cognition remained. Conclusions Although residents require a similar intensive level of nursing home care

  17. Combined single crystal polarized XAFS and XRD at high pressure: probing the interplay between lattice distortions and electronic order at multiple length scales in high Tc cuprates (United States)

    Fabbris, G.; Hücker, M.; Gu, G. D.; Tranquada, J. M.; Haskel, D.


    Some of the most exotic material properties derive from electronic states with short correlation length (~10-500 {\\AA}), suggesting that the local structural symmetry may play a relevant role in their behavior. Here we discuss the combined use of polarized x-ray absorption fine structure and x-ray diffraction at high pressure as a powerful method to tune and probe structural and electronic orders at multiple length scales. Besides addressing some of the technical challenges associated with such experiments, we illustrate this approach with results obtained in the cuprate La$_{1.875}$Ba$_{0.125}$CuO$_4$, in which the response of electronic order to pressure can only be understood by probing the structure at the relevant length scales.

  18. "Bottom-up" meets "top-down" : self-assembly to direct manipulation of nanostructures on length scales from atoms to microns.

    Energy Technology Data Exchange (ETDEWEB)

    Swartzentruber, Brian Shoemaker


    This document is the final SAND Report for the LDRD Project 102660 - 'Bottomup' meets 'top-down': Self-assembly to direct manipulation of nanostructures on length scales from atoms to microns - funded through the Strategic Partnerships investment area as part of the National Institute for Nano-Engineering (NINE) project.

  19. Bridging the Gap Between Large-scale Data Sets and Analyses: Semi-automated Methods to Facilitate Length Polymorphism Scoring and Data Analyses. (United States)

    Amplified fragment length polymorphism (AFLP) markers can be developed more quickly and at a lower cost than microsatellite and single nucleotide polymorphism markers, which makes them ideal markers for large-scale studies of understudied taxa — such as species at risk. However,...

  20. 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


    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

  1. The Scales of Time, Length, Mass, Energy, and Other Fundamental Physical Quantities in the Atomic World and the Use of Atomic Units in Quantum Mechanical Calculations (United States)

    Teo, Boon K.; Li, Wai-Kee


    This article is divided into two parts. In the first part, the atomic unit (au) system is introduced and the scales of time, space (length), and speed, as well as those of mass and energy, in the atomic world are discussed. In the second part, the utility of atomic units in quantum mechanical and spectroscopic calculations is illustrated with…

  2. Impact of water dilution and cation tail length on ionic liquid characteristics: Interplay between polar and non-polar interactions (United States)

    Hegde, Govind A.; Bharadwaj, Vivek S.; Kinsinger, Corey L.; Schutt, Timothy C.; Pisierra, Nichole R.; Maupin, C. Mark


    The recalcitrance of lignocellulosic biomass poses a major challenge that hinders the economical utilization of biomass for the production of biofuel, plastics, and chemicals. Ionic liquids have become a promising solvent that addresses many issues in both the pretreatment process and the hydrolysis of the glycosidic bond for the deconstruction of cellulosic materials. However, to make the use of ionic liquids economically viable, either the cost of ionic liquids must be reduced, or a less expensive solvent (e.g., water) may be added to reduce the overall amount of ionic liquid used in addition to reducing the viscosity of the binary liquid mixture. In this work, we employ atomistic molecular dynamics simulations to investigate the impact of water dilution on the overall liquid structure and properties of three imidazolium based ionic liquids. It is found that ionic liquid-water mixtures exhibit characteristics that can be grouped into two distinct regions, which are a function of the ionic liquid concentration. The trends observed in each region are found to correlate with the ordering in the local structure of the ionic liquid that arises from the dynamic interactions between the ion pairs. Simulation results suggest that there is a high level of local ordering in the molecular structure at high concentrations of ionic liquids that is driven by the aggregation of the cationic tails and the anion-water interactions. It is found that as the concentration of ionic liquids in the binary mixture is decreased, there is a point at which the competing self and cross interaction energies between the ionic liquid and water shifts away from a cation-anion dominated regime, which results in a significant change in the mixture properties. This break point, which occurs around 75% w/w ionic liquids, corresponds to the point at which water molecules percolate into the ionic liquid network disrupting the ionic liquids' nanostructure. It is observed that as the cationic alkyl

  3. The relationship between shear force, compression, collagen characteristics, desmin degradation and sarcomere length in lamb biceps femoris. (United States)

    Starkey, Colin P; Geesink, Geert H; van de Ven, Remy; Hopkins, David L


    This study aimed to identity the relationships between known variants of tenderness (collagen content (total and soluble), desmin degradation and sarcomere length) and shear force and compression in the biceps femoris aged for 14days from 112 mixed sex lambs. Desmin degradation was related to compression (P<0.05) such that as desmin degradation increased compression decreased. Sarcomere length (SL) was related to shear force (P<0.05), such that as SL increased shear force declined. Shear force was also related to compression (P<0.05), and soluble collagen (P<0.05), with male lambs producing higher shear force values than females (4.4±1.72N: P<0.05) when adjusted for compression, sarcomere length and soluble collagen. The findings from this experiment indicate that the known variants (soluble collagen, sarcomere length and desmin degradation) are related to shear force and compression in ovine biceps femoris.


    Directory of Open Access Journals (Sweden)

    Syahrial Syarif


    Full Text Available Small-scale enterprises in West Sumatra experienced slow growth and some constraints in their development process. In 1998, small businesses represented 99.61% of total business units operating in West Sumatra and absorbed 88.8% of total employment. The orientation of their businesses mostly on domestic market although recently they enter international market. Export contribution of small businesses still very low but growing steadily during the last three years. This research showed that enterprises dealing with embroideries, garments and handicrafts are ambitiously orienting their products towards foreign markets. At the same time these business categories are also proven to be the most profitable businesses.

  5. Small-scale characteristics of extremely high latitude aurora

    Directory of Open Access Journals (Sweden)

    J. A. Cumnock


    Full Text Available We examine 14 cases of an interesting type of extremely high latitude aurora as identified in the precipitating particles measured by the DMSP F13 satellite. In particular we investigate structures within large-scale arcs for which the particle signatures are made up of a group of multiple distinct thin arcs. These cases are chosen without regard to IMF orientation and are part of a group of 87 events where DMSP F13 SSJ/4 measures emissions which occur near the noon-midnight meridian and are spatially separated from both the dawnside and duskside auroral ovals by wide regions with precipitating particles typical of the polar cap. For 73 of these events the high-latitude aurora consists of a continuous region of precipitating particles. We focus on the remaining 14 of these events where the particle signatures show multiple distinct thin arcs. These events occur during northward or weakly southward IMF conditions and follow a change in IMF By. Correlations are seen between the field-aligned currents and plasma flows associated with the arcs, implying local closure of the FACs. Strong correlations are seen only in the sunlit hemisphere. The convection associated with the multiple thin arcs is localized and has little influence on the large-scale convection. This also implies that the sunward flow along the arcs is unrelated to the overall ionospheric convection.

  6. Micellization of dodecyltrimethylammonium bromide in water-dimethylsulfoxide mixtures: a multi-length scale approach in a model system. (United States)

    Peyre, Véronique; Bouguerra, Sabah; Testard, Fabienne


    The micellization in mixed solvent was studied using conductimetry, density measurements (molar volumes), and small angle neutron scattering (SANS) to explore dodecyltrimethylammonium bromide (DTABr) micelle formation throughout the entire composition range of water-dimethylsulfoxide (DMSO) mixtures. As the concentration of DMSO was increased in the mixture, the critical micelle concentration (CMC) increased, the aggregation number decreased and the ionization degree increased, until no aggregates could be detected any more for DMSO molar fraction higher than 0.51. The results were consistent with the presence of globular micelles interacting via a coulombic potential. The experimental CMC values and aggregation numbers were successfully reconciled with a molecular thermodynamic model describing the micellization process in solvent mixtures (R. Nagarajan and C.-C. Wang, Langmuir 16 (2000) 5242). The structural and thermodynamic characterization of the micelles agreed with the prediction of a dissymmetric solvation of the surfactant entity: the hydrocarbon chain was surrounded only by DMSO while the polar head was surrounded only by water. The decrease in the ionization degree was due to the condensation of the counterions and was definitely linked to the geometrical characteristics of the aggregates and by no means to the CMC or salinity. This multi-technique study provides new insight into the role of solvation in micellization and the reason for the decrease in ionization degree, emphasizing the dissymmetric solvation of the chain by DMSO and the head by water. This is the first time that, for a given surfactant in solvent mixtures, micellization is described using combined analysis from molecular to macroscopic scale.

  7. Structure and mechanism of maximum stability of isolated alpha-helical protein domains at a critical length scale. (United States)

    Qin, Zhao; Fabre, Andrea; Buehler, Markus J


    The stability of alpha helices is important in protein folding, bioinspired materials design, and controls many biological properties under physiological and disease conditions. Here we show that a naturally favored alpha helix length of 9 to 17 amino acids exists at which the propensity towards the formation of this secondary structure is maximized. We use a combination of thermodynamical analysis, well-tempered metadynamics molecular simulation and statistical analyses of experimental alpha helix length distributions and find that the favored alpha helix length is caused by a competition between alpha helix folding, unfolding into a random coil and formation of higher-order tertiary structures. The theoretical result is suggested to be used to explain the statistical distribution of the length of alpha helices observed in natural protein structures. Our study provides mechanistic insight into fundamental controlling parameters in alpha helix structure formation and potentially other biopolymers or synthetic materials. The result advances our fundamental understanding of size effects in the stability of protein structures and may enable the design of de novo alpha-helical protein materials.

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

    Energy Technology Data Exchange (ETDEWEB)

    Douglas W. Marshall


    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.

  9. Psychometric Characteristics of the California Preschool Social Competence Scale in a Spanish Population Sample (United States)

    Julvez, Jordi; Forns, Maria; Ribas-Fito, Nuria; Mazon, Carlos; Torrent, Maties; Garcia-Esteban, Raquel; Ellison-Loschmann, Lis; Sunyer, Jordi


    Research Findings: Few rating scales measure social competence in very young Spanish or Catalan children. We aimed to analyze the psychometric characteristics of the California Preschool Social Competence Scale (CPSCS) when applied to a Spanish- and Catalan-speaking population. Children were rated by their respective teachers within 6 months…

  10. 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


    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...

  11. 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)



    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.

  12. Model studies of spectral and photophysical characteristics of a series of donor acceptor polyenes of different length (United States)

    El-Gezawy, Hani; Rettig, Wolfgang


    The photophysical behaviour of a series of donor-acceptor-polyenes of different length: 4-dimethylamino-4'-cyanostilbene (DCS), 4-dimethylamino-4'-cyano-1,4-diphenylbutadiene (DCB) and 4-dimethylamino-4'-cyano-1,4-diphenylhexatriene (DCH) has been studied by means of steady state and time resolved fluorescence and low temperature measurements. Quantum chemical calculations were performed for comparison. For all three dyes, the fluorescence quantum yields show a maximum in the most polar solvents. A pronounced solvatochromic behaviour is only observed for the emission spectra whereas the absorption spectra remain nearly unaffected. The nonradiative decay decreases in the order DCS > DCB > DCH. Similarly, the radiative rate constant decreases in this order, contrary to the usual behaviour for a lengthening of the π-system. The chain-length dependence of the dipole moments of the relaxed excited state μe is better described by the Onsager radius derived from molecular length rather than from the density approach. Both calculations and experiments support the conclusion that the emissive state is not a TICT state.

  13. Effects of maternal and infant characteristics on birth weight and gestation length in a colony of rhesus macaques (Macaca mulatta). (United States)

    Hopper, Kelly J; Capozzi, Denise K; Newsome, Joseph T


    A retrospective study using maternal and birth statistics from an open, captive rhesus macaque colony was done to determine the effects of parity, exposure to simian retrovirus (SRV), housing, maternal parity, and maternal birth weight on infant birth weight, viability and gestation length. Retrospective colony statistics for a 23-y period indicated that birth weight, but not gestation length, differed between genders. Adjusted mean birth weights were higher in nonviable infants. Mothers positive for SRV had shorter gestations, but SRV exposure did not affect neonatal birth weights or viability. Infants born in cages had longer gestations than did those born in pens, but neither birth weight nor viability differed between these groups. Maternal birth weight did not correlate with infant birth weight but positively correlated with gestation length. Parity was correlated with birth weight and decreased viability. Increased parity of the mother was associated with higher birth weight of the infant. A transgenerational trend toward increasing birth weight was noted. The birth statistics of this colony were consistent with those of other macaque colonies. Unlike findings for humans, maternal birth weight had little predictive value for infant outcomes in rhesus macaques. Nonviable rhesus infants had higher birth weights, unlike their human counterparts, perhaps due to gestational diabetes occurring in a sedentary caged population. Similar to the situation for humans, multiparity had a protective effect on infant viability in rhesus macaques.

  14. Dependence of the sediment delivery ratio on scale and its fractal characteristics

    Institute of Scientific and Technical Information of China (English)

    Xiaoming Zhang; Sihong Wu; Wenhong Cao; Jianchao Guan; Zhaoyan Wang


    The sediment delivery ratio (SDR) is an indicator used to determine the capacity for eroded sediment to be delivered to the outlet of a particular basin. Based on systematic reviews of SDR studies in China and abroad during the last 50 years, this study analyzes whether the SDR has scale-dependent characteristics and discusses the fractal characteristics of the SDR. In addition, the SDR in various watersheds in China and abroad showed correlations with temporal and spatial scales, which means that the SDR depends on watershed scale. Moreover, the SDR can be quantitatively expressed and scaled using fractal dimension under certain temporal and spatial scales. Within a nested watershed, a proposed SDR scale transfer model was constructed using the SDR at a typical watershed unit scale with an area of approximately 1 km2 (SDR0) and a fractal dimension of the SDR at a nested watershed scale (D). This research also points out that the study and calculation of the SDR cannot be correct without considering its scale dependence. It is a valid and useful approach to construct SDR scaling models by using fractal dimension, which could be an interesting research topic regarding SDR scaling in the future.

  15. Prediction of vibration characteristics in beam structure using sub-scale modeling with experimental validation (United States)

    Zai, Behzad Ahmed; Sami, Saad; Khan, M. Amir; Ahmad, Furqan; Park, Myung Kyun


    Geometric or sub-scale modeling techniques are used for the evaluation of large and complex dynamic structures to ensure accurate reproduction of load path and thus leading to true dynamic characteristics of such structures. The sub-scale modeling technique is very effective in the prediction of vibration characteristics of original large structure when the experimental testing is not feasible due to the absence of a large testing facility. Previous researches were more focused on free and harmonic vibration case with little or no consideration for readily encountered random vibration. A sub-scale modeling technique is proposed for estimating the vibration characteristics of any large scale structure such as Launch vehicles, Mega structures, etc., under various vibration load cases by utilizing precise scaled-down model of that dynamic structure. In order to establish an analytical correlation between the original structure and its scaled models, different scale models of isotropic cantilever beam are selected and analyzed under various vibration conditions( i.e. free, harmonic and random) using finite element package ANSYS. The developed correlations are also validated through experimental testing. The prediction made from the vibratory response of the scaled-down beam through the established sets of correlation are found similar to the response measured from the testing of original beam structure. The established correlations are equally applicable in the prediction of dynamic characteristics of any complex structure through its scaled-down models. This paper presents modified sub-scale modeling technique that enables accurate prediction of vibration characteristics of large and complex structure under not only sinusoidal but also for random vibrations.

  16. Multi-Length Scale-Enriched Continuum-Level Material Model for Kevlar (registered trademark)-Fiber-Reinforced Polymer-Matrix Composites (United States)


    polymer matrix composite materials display quite complex deformation and failure behavior under ballistic/blast impact loading conditions. This complexity is generally attributed to a number of factors such as (a) hierarchical/multi-length scale architecture of the material microstructure; (b) nonlinear, rate-dependent and often pressure-sensitive mechanical response; and (c) the interplay of various intrinsic phenomena and processes such as fiber twisting, interfiber friction/sliding, etc. Material models currently employed in the computational engineering

  17. 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


    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...

  18. Androgen receptor gene CAG repeat length as modifier of the association between Persistent Organohalogen Pollutant exposure markers and semen characteristics

    DEFF Research Database (Denmark)

    Giwercman, Aleksander; Rylander, Lars; Rignell-Hydbom, Anna;


    OBJECTIVES: Exposure to persistent organohalogen pollutants was suggested to impair male reproductive function. A gene-environment interaction has been proposed. No genes modifying the effect of persistent organohalogen pollutants on reproductive organs have yet been identified. We aimed...... and morphology) and DNA fragmentation index (DFI) were determined. CAG and GGN repeat lengths were determined by direct sequencing of leukocyte DNA. RESULTS: A statistically significant interaction was found between the CB-153 group and CAG repeat category in relation to sperm concentration and total sperm count...

  19. 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


    -to-roll methods is taken as a premise, and thus the progression from a highly successful laboratory technique (i.e., spin coating) to large-scale roll-to-roll equipment is described in terms of all of the intermediate steps that must be available to make the transfer possible. Spin coating is compatible...

  20. Criterion Noise in Ratings-Based Recognition: Evidence from the Effects of Response Scale Length on Recognition Accuracy (United States)

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


    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…

  1. Effect of side-chain length on rectification and photovoltaic characteristics of poly(3-alkylthiophene) Schottky barriers

    Energy Technology Data Exchange (ETDEWEB)

    Fang Yih; Chen Showan (Dept. of Chemical Engineering, National Tsing-Hua Univ., Hsinchu (Taiwan)); Chu, M.L. (Inst. of Electro-Optical Engineering, National Chiao-Tung Univ., Hsinchu (Taiwan))


    Schottky diodes of aluminium/poly(3-alkylthiophene) (P3AT)/indium-tin oxide (ITO) with large area (0.15-0.5 cm[sup 2]) are prepared using the proposed new casting technique. The P3ATs investigated involve poly(3-butylthiophene) (P3BT), poly(3-octylthiophene) (P3OT) and poly(3-dodecylthiophene) (P3DDT), which are prepared using the chemical method. The diodes, in which P3AT behaves as a p-type semiconductor, exhibit a moderate rectifying behaviour and low leakage current. Photovoltaic measurements show a power conversion efficiency of about 10[sup -2]-10[sup -3]% at a light intensity of 0.5-5 mW/cm[sup 2], which decreases with increasing light intensity. The longer alkyl side-chain length of P3ATs can cause a lower rectifying effect, barrier height, depletion region width and photovoltaic conversion efficiency. (orig.).

  2. Large-scale collection and annotation of full-length enriched cDNAs from a model halophyte, Thellungiella halophila

    Directory of Open Access Journals (Sweden)

    Seki Motoaki


    Full Text Available Abstract Background Thellungiella halophila (also known as Thellungiella salsuginea is a model halophyte with a small plant size, short life cycle, and small genome. It easily undergoes genetic transformation by the floral dipping method used with its close relative, Arabidopsis thaliana. Thellungiella genes exhibit high sequence identity (approximately 90% at the cDNA level with Arabidopsis genes. Furthermore, Thellungiella not only shows tolerance to extreme salinity stress, but also to chilling, freezing, and ozone stress, supporting the use of Thellungiella as a good genomic resource in studies of abiotic stress tolerance. Results We constructed a full-length enriched Thellungiella (Shan Dong ecotype cDNA library from various tissues and whole plants subjected to environmental stresses, including high salinity, chilling, freezing, and abscisic acid treatment. We randomly selected about 20 000 clones and sequenced them from both ends to obtain a total of 35 171 sequences. CAP3 software was used to assemble the sequences and cluster them into 9569 nonredundant cDNA groups. We named these cDNAs "RTFL" (RIKEN Thellungiella Full-Length cDNAs. Information on functional domains and Gene Ontology (GO terms for the RTFL cDNAs were obtained using InterPro. The 8289 genes assigned to InterPro IDs were classified according to the GO terms using Plant GO Slim. Categorical comparison between the whole Arabidopsis genome and Thellungiella genes showing low identity to Arabidopsis genes revealed that the population of Thellungiella transport genes is approximately 1.5 times the size of the corresponding Arabidopsis genes. This suggests that these genes regulate a unique ion transportation system in Thellungiella. Conclusion As the number of Thellungiella halophila (Thellungiella salsuginea expressed sequence tags (ESTs was 9388 in July 2008, the number of ESTs has increased to approximately four times the original value as a result of this effort. Our

  3. Effect of gate-length shortening on the terahertz small-signal and self-oscillations characteristics of field-effect transistors (United States)

    Starikov, E.; Shiktorov, P.; Gružinskis, V.; Marinchio, H.; Palermo, C.; Varani, L.


    We investigate the shortening of the gate-length in submicrometric and nanometric field-effect transistors as a powerful tool to improve their self-oscillations performances in the terahertz frequency region due to the appearance of the Dyakonov-Shur instability. The theoretical model is based on the numerical solution of hydrodynamic equations for the electron transport in FETs/HEMTs channels. We show that a decrease of the gate length allows, on the one hand, to increase the intrinsic resonant frequencies near 1 THz and, on the other hand, to improve the conditions for the onset of the Dyakonov-Shur instability and related phenomena. The small-signal characteristics calculated under constant drain-voltage operation are compared with the drain-voltage self-oscillations calculated under constant drain-current operation.

  4. Characteristics of depression in Parkinson's disease: evaluating with Zung's Self-Rating Depression Scale. (United States)

    Kanda, Fumio; Oishi, Kenichi; Sekiguchi, Kenji; Kuga, Atsushi; Kobessho, Hiroshi; Shirafuji, Toshihiko; Higuchi, Masatsugu; Ishihara, Hiroyuki


    The purpose of the study was to elucidate characteristics of depression in Parkinson's disease (PD). Fifty-eight PD patients were evaluated with Zung's Self-Rating Depression Scale (SDS) and the Unified Parkinson's Disease Rating Scale (UPDRS). Scores for "suicidal ideation" on the SDS correlated with posture and gait disturbances on the UPDRS. Twenty-six patients with spinocerebellar degeneration (SCD) were also evaluated with the SDS. SDS scores for "indecisiveness" and "constipation" were significantly higher in PD patients than SCD patients. Our results suggest that depression is common in disabled persons but PD patients might have a characteristic clinical presentation.

  5. Characteristic time scales in the American dollar-Mexican peso exchange currency market (United States)

    Alvarez-Ramirez, Jose


    Daily fluctuations of the American dollar-Mexican peso exchange currency market are studied using multifractal analysis methods. It is found evidence of multiaffinity of daily fluctuations in the sense that the qth-order (roughness) Hurst exponent Hq varies with changes in q. It is also found that there exist several characteristic time scales ranging from week to year. Accordingly, the market exhibits persistence in the sense that instabilities introduced by market events acting around the characteristic time scales (mainly, quarter and year) would propagate through the future market activity. Some implications of our results on the regulation of the dollar-mexpeso market activity are discussed.

  6. 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


    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.)

  7. Gate length scaling effect on high-electron mobility transistors devices using AlGaN/GaN and AlInN/AlN/GaN heterostructures. (United States)

    Liao, S Y; Lu, C C; Chang, T; Huang, C F; Cheng, C H; Chang, L B


    Compared to AlGaN/GaN HEMT with 0.15 μm T-gate length, the AlInN/AlN/GaN one exhibits much higher current density and transconductance of 1558 mA/mm at Vd = 2 V and 330 mS/mm, respectively. The high extrinsic ft and fmax of 82 GHz and 70 GHz are extracted from AlInN/AlN/GaN HEMT. Besides, we find that the transconductance roll-off is significant in AlGaN/GaN, but largely improved in AlInN/AlN/GaN HEMT, suggesting that the high carrier density and lattice-matched epitaxial heterostructure is important to reach both large RF output power and high operation frequency, especially for an aggressively gate length scaling.

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

    CERN Document Server

    Shinde, D P; Mishra, R K


    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.

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

    KAUST Repository

    Brisard, S.


    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.

  10. Metric characteristics of the Self-efficacy Scale: a preliminary study

    Directory of Open Access Journals (Sweden)

    Špela Frlec


    Full Text Available The concept of self-efficacy is presented in the paper, which has not been applied yet in empirical psychological research in Slovenia, and selected metric characteristics of the translated and adapted Schwarzer's generalised self-efficacy scale (LSU are analysed. The introduction focuses on self-efficacy within organisational context, the self-efficacy versus self-esteem issue and the Bandura's socio-cognitive paradigm. The psychometric analyses are based on a sample of 120 undergraduates, supplemented by comparisons with a sample of 15 employees. In addition to the LSU, a self-regulation scale was applied (another adaptation to Slovenian, a standard trait-anxiety scale and a self-confidence scale. The self-efficacy scale is analysed in detail – including the item level, while the other three instruments are only addressed on the scale level. LSU's reliability in terms of internal consistency proved to be sufficient (Cronbach α 0,77 for the students and 0,87 for the employees. Concurrent validity was verified through indicator convergence (a high positive correlation with the two related scales and a high negative correlation with the anxiety scale. Another piece of evidence in favour of construct validity of the LSU is provided by lack of significant differences between distinct groups of students on any of the scales, as well as by significant differences between the students and the employees on all the four scales.

  11. 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


    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.

  12. Application of scaling-rule theory in crustal rock fracture to studying characteristics of seismological precursors associated with M=6.1 Shandan-Minle earthquake

    Institute of Scientific and Technical Information of China (English)

    RONG Dai-lu; LI Ya-rong; HAN Xiao-ming


    In the paper, we introduce Allegre's scaling-rule theory of rock fracture and the probability to develop a method for predicting earthquake occurrence time on its basis. As an example, we study the characteristics of seismological precursors (seismic spatial correlation length and coda Qc) associated with the earthquake (M=6.1) occurred in Shandan-Minle, Gansu Province. The results show an increasing trend of seismic spatial correlation length and coda Qc before the earthquake. And a power exponent relation is used to fit the increasing variation form of these two parameters. The study has provided a basis for creating a method and finding indexes to predict the earthquake occurrence time by using the monitored seismic spatial correlation length and coda Qc.

  13. Atomistic simulation of laser-pulse surface modification: Predictions of models with various length and time scales

    Energy Technology Data Exchange (ETDEWEB)

    Starikov, Sergey V., E-mail:; Pisarev, Vasily V. [Moscow Institute of Physics and Technology, Dolgoprudny 141700 (Russian Federation); Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412 (Russian Federation)


    In this work, the femtosecond laser pulse modification of surface is studied for aluminium (Al) and gold (Au) by use of two-temperature atomistic simulation. The results are obtained for various atomistic models with different scales: from pseudo-one-dimensional to full-scale three-dimensional simulation. The surface modification after laser irradiation can be caused by ablation and melting. For low energy laser pulses, the nanoscale ripples may be induced on a surface by melting without laser ablation. In this case, nanoscale changes of the surface are due to a splash of molten metal under temperature gradient. Laser ablation occurs at a higher pulse energy when a crater is formed on the surface. There are essential differences between Al ablation and Au ablation. In the first step of shock-wave induced ablation, swelling and void formation occur for both metals. However, the simulation of ablation in gold shows an additional athermal type of ablation that is associated with electron pressure relaxation. This type of ablation takes place at the surface layer, at a depth of several nanometers, and does not induce swelling.

  14. Coupling Length Scales for Multiscale Atomistics-Continuum Simulations: Atomistically Induced Stress Distributions in Si/Si3N4 Nanopixels (United States)

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


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

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

    Institute of Scientific and Technical Information of China (English)

    Shen Yi


    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.

  16. The role of length scales in bridging the gap between rock CPO and seismic signals of crustal anisotropy (United States)

    Okaya, D.; Johnson, S. E.; Vel, S. S.; Song, W. J.; Christensen, N. I.


    Recent studies based on laboratory petrophysics and in particular EBSD-based calculations indicate material rock anisotropy for crustal rocks can possess significant low orders of symmetry. These symmetries based on elastic tensor calculations can range from hexagonal and orthorhombic down to monoclinic and triclinic. On the other hand, interpretation of field seismic data yield crustal anisotropy of fast- or slow-axis transverse isotropy (hexagonal) symmetry at best; identification of orthorhombic symmetry is barely possible. Seismic results are often limited to simple orientations of the symmetry axes, such as vertical (radial anisotropy) or horizontal (azimuthal anisotropy). The physical scales of earth anisotropic fabrics and of seismic waves affect the types of information that may be extracted from seismic signals. A seismic wave has inherent limits to resolving capabilities, usually measured as some percentage of its wavelength, λ. This wave will accumulate anisotropic signal in two ways based on its path through anisotropic media of physical size, L: (1) When the wave is much smaller than the anisotropic material (λ > L), the wave will not see details of the material but will respond to just the bulk average of the material. In the first case, the wave will be sensitive to large scale earth changes such as limbs of an antiformal mountain range. The accumulating anisotropic seismic signal can get complicated (e.g., shear wave splits of splits). In the second case, the wave is too large to see any fine detail, and the material can be represented by an equivalent "effective media" that produces the same seismic response. Geometrical structure is a factor that helps bridge the scales of rock CPO to lower resolution seismic signals. Local rock CPO can fill or be mapped into a structure that is large enough for a seismic wave to respond to. We use tensor representation of anisotropic elasticity to formulate a way to separate structural effects from local rock

  17. 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


    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...

  18. Prediction of anisotropic material behavior based on multiresolution continuum mechanics in consideration of a characteristic length scale

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dock Jin; Choi, Jae Boong; Kim, Moon Ki [Sungkyunkwan Univ., Suwon (Korea, Republic of); Chang, Yoon Suk [Kyunghee Univ., Suwon (Korea, Republic of)


    New advanced materials have received more attention from many scientists and engineers because of their outstanding chemical, electrical, thermal, optical, and mechanical properties. Since the design of advanced material by experiments requires high cost and time, numerical approaches have always been of great interest. In this paper, finite element analysis of anisotropic material behavior has been carried out based on a multiresolution continuum theory. Gurson Tvergaard Needleman (GTN) damage model has been applied as a constitutive model at macroscale. Effects of plastic anisotropy on deformation behavior are assessed using Hill's 48 yield function for anisotropic material and von Mises yield function for isotropic material, respectively. The material parameters for both isotropic and anisotropic damage models have systematically been determined from microstructure through unit cell modeling. The newly proposed linear approximation of local velocity gradient resolved the underdetermined problem of the previous homogenization process. Anisotropic material behaviors of a tensile specimen have been investigated by the proposed multiresolution continuum theory.

  19. 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.


    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.

  20. Enhancement of the photocatalytic activity of TiO2 through spatial structuring and particle size control: from subnanometric to submillimetric length scale. (United States)

    Aprile, Carmela; Corma, Avelino; Garcia, Hermenegildo


    This review summarizes the physical approaches towards enhancement of the photocatalytic activity of titanium dioxide by controlling this semiconductor in a certain length scale from subnanometric to submillimetric distances and provides examples in which the photocatalytic activity of TiO2 is not promoted by doping or changes in the chemical composition, but rather by application of physical concepts and spatial structuring of the semiconductor. Thus, encapsulation inside the micropores and cavities of zeolites (about 1 nm) renders small titanium oxide clusters with harnessed photocatalytic activity. On the other hand, nanometric titanium particles can be ordered forming structured periodic mesoporous materials with high specific surface area and well defined porosity. Titiania nanotubes of micrometric length, either independent or forming a membrane, also exhibit unique photocatalytic activity as consequence of the long diffusion length of charge carriers along the nanotube axis. Finally, photonic crystals with an inverse opal structure and the even more powerful concept of photonic sponges can serve to slow down visible light photons inside the material, increasing the effective optical path in such a way that light absorption near the absorption onset of the material is enhanced considerably. All these physical-based approaches have shown their potential in enhancing the photocatalytic activity of titania, paving the way for a new generation of novel structured photocatalysts in which physical and chemical concepts are combined.

  1. Investigation of scaling characteristics for defining design environments due to transient ground winds and near-field, nonlinear acoustic fields (United States)

    Shih, C. C.


    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.

  2. A first constraint on the thick disk scale-length: Differential radial abundances in K giants at Galactocentric radii 4, 8, and 12 kpc

    CERN Document Server

    Bensby, T; Oey, M S; Yong, D; Meléndez, J


    Based on high-resolution spectra obtained with the MIKE spectrograph on the Magellan telescopes we present detailed elemental abundances for 20 red giant stars in the outer Galactic disk, located at Galactocentric distances between 9 and 13 kpc. The outer disk sample is complemented with samples of red giants from the inner Galactic disk and the solar neighbourhood, analysed using identical methods. For Galactocentric distances beyond 10 kpc, we only find chemical patterns associated with the local thin disk, even for stars far above the Galactic plane. Our results show that the relative densities of the thick and thin disks are dramatically different from the solar neighbourhood, and we therefore suggest that the radial scale length of the thick disk is much shorter than that of the thin disk. We make a first estimate of the thick disk scale-length of L_thick=2.0 kpc, assuming L_thin=3.8 kpc for the thin disk. We suggest that radial migration may explain the lack of radial age, metallicity, and abundance gra...

  3. Current-voltage characteristics of quantum-point contacts in the closed-channel regime: Transforming the bias voltage into an energy scale

    DEFF Research Database (Denmark)

    Gloos, K.; Utko, P.; Aagesen, M.;


    We investigate the I(V) characteristics (current versus bias voltage) of side-gated quantum-point contacts, defined in GaAs/AlxGa1-xAs heterostructures. These point contacts are operated in the closed-channel regime, that is, at fixed gate voltages below zero-bias pinch-off for conductance. Our...... analysis is based on a single scaling factor, extracted from the experimental I(V) characteristics. For both polarities, this scaling factor transforms the change of bias voltage into a change of electron energy. The latter is determined with respect to the top of the potential barrier of the contact....... Such a built-in energy-voltage calibration allows us to distinguish between the different contributions to the electron transport across the pinched-off contact due to thermal activation or quantum tunneling. The first involves the height of the barrier, and the latter also its length. In the model that we...

  4. 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


    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.

  5. Scaling in the Optical Characteristics of Aperiodic Structures with Self-Similarity Symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Zotov, A. M.; Korolenko, P. V., E-mail:; Mishin, A. Yu. [Moscow State University (Russian Federation)


    The properties of diffraction gratings and multilayered systems constructed using 1D models of quasicrystals are considered based on numerical simulation. It is shown that there is a direct relationship between the self-similarity symmetry of quasicrystals and scaling in the characteristics of the above-mentioned optical devices. The degree of structural correspondence between the graphical representations of the geometric properties of crystals, light diffraction patterns of gratings, and the transmission spectra of multilayered systems is estimated. It is shown that certain types of self-similarity symmetry make the characteristics of aperiodic diffraction gratings highly stable to a change in the size ratio of forming elements.

  6. Characteristic time scales of mixing, mass transfer and biomass growth in a Taylor vortex algal photobioreactor. (United States)

    Gao, Xi; Kong, Bo; Vigil, R Dennis


    Recently it has been demonstrated that algal biomass yield can be enhanced using fluid flow patterns known as Taylor vortices. It has been suggested that these growth rate improvements can be attributed to improved light delivery as a result of rapid transport of microorganisms between light and dark regions of the reactor. However, Taylor vortices also strongly impact fluid mixing and interphase (gas-liquid) mass transport, and these in turn may also explain improvements in biomass productivity. To identify the growth-limiting factor in a Taylor vortex algal photobioreactor, experiments were performed to determine characteristic time scales for mixing and mass transfer. By comparing these results with the characteristic time scale for biomass growth, it is shown that algal growth rate in Taylor vortex reactors is not limited by fluid mixing or interphase mass transfer, and therefore the observed biomass productivity improvements are likely attributable to improved light utilization efficiency.

  7. 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


    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.

  8. Analysis on the Meso-scale Characteristics of a Hail Process in Linyi Area

    Institute of Scientific and Technical Information of China (English)


    [Objective] The research aimed to study the meso-scale characteristics of a hail process in Linyi area. [Method] By comprehensively using MICAPS conventional observation data, automatic encryption ground station, MM5 model product and Doppler weather radar data, a strong convective hail weather process which happened in Shandong Peninsula and southeast of Shandong on May 30, 2010 was analyzed. The circulation background and physical mechanism of strong convection weather occurrence, the features of meso- an...

  9. Simple Model for Simulating Characteristics of River Flow Velocity in Large Scale

    Directory of Open Access Journals (Sweden)

    Husin Alatas


    Full Text Available We propose a simple computer based phenomenological model to simulate the characteristics of river flow velocity in large scale. We use shuttle radar tomography mission based digital elevation model in grid form to define the terrain of catchment area. The model relies on mass-momentum conservation law and modified equation of motion of falling body in inclined plane. We assume inelastic collision occurs at every junction of two river branches to describe the dynamics of merged flow velocity.

  10. The Extended Relativity Theory in Born-Clifford Phase Spaces with a Lower and Upper Length Scales and Clifford Group Geometric Unification

    CERN Document Server

    Castro, C


    We construct the Extended Relativity Theory in Born-Clifford-Phase spaces with an upper and lower length scales (infrared/ultraviolet cutoff). The invariance symmetry leads naturally to the real Clifford algebra Cl (2, 6, R ) and complexified Clifford Cl_C ( 4 ) algebra related to Twistors. We proceed with an extensive review of Smith's 8D model based on the Clifford algebra Cl ( 1 ,7) that reproduces at low energies the physics of the Standard Model and Gravity; including the derivation of all the coupling constants, particle masses, mixing angles, ....with high precision. Further results by Smith are discussed pertaining the interplay among Clifford, Jordan, Division and Exceptional Lie algebras within the hierarchy of dimensions D = 26, 27, 28 related to bosonic string, M, F theory. Two Geometric actions are presented like the Clifford-Space extension of Maxwell's Electrodynamics, Brandt's action related the 8D spacetime tangent-bundle involving coordinates and velocities (Finsler geometries) followed by a...

  11. Patterning at the 10 nanometer length scale using a strongly segregating block copolymer thin film and vapor phase infiltration of inorganic precursors (United States)

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


    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

  12. 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


    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.

  13. 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.


    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)

  14. Upscaling analysis of aerodynamic roughness length based on in situ data at different spatial scales and remote sensing in north Tibetan Plateau (United States)

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


    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

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

    Directory of Open Access Journals (Sweden)

    Mutrie Nanette


    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

  16. The Aging Males' Symptoms (AMS scale: review of its methodological characteristics

    Directory of Open Access Journals (Sweden)

    Moore Claudia


    Full Text Available Abstract Background The current paper reviews data from different sources to get a closer impression on the psychometric and other methodological characteristics of the Aging Males' Symptoms (AMS scale gathered recently. The scale was designed and standardized as self-administered scale to (a to assess symptoms of aging (independent from those which are disease-related between groups of males under different conditions, (b to evaluate the severity of symptoms over time, and (c to measure changes pre- and post androgen replacement therapy. The scale is in widespread use (14 languages. Method Original data from different studies in many countries were centrally analysed to evaluate reliability and validity of the AMS. Results Reliability measures (consistency and test-retest stability were found to be good across countries, although the sample size was sometimes small. Validity: The internal structure of the AMS in healthy and androgen deficient males, and across countries was sufficiently similar to conclude that the scale really measures the same phenomenon. The sub-scores and total score correlations were high (0.8–0.9 but lower among the sub-scales (0.5–0.7. This however suggests that the subscales are not fully independent. The comparison with other scales for aging males or screening instruments for androgen deficiency showed sufficiently good correlations, illustrating a good criterion-oriented validity. The same is true for the comparison with the generic quality-of-life scale SF36 where also high correlation coefficients have been shown. Methodological analyses of a treatment study of symptomatic males with testosterone demonstrated the ability of the AMS scale to measure treatment effect, irrespective of the severity of complaints before therapy. It was also shown that the AMS result can predict the independently generated (physician's opinion about the individual treatment effect. Conclusion The currently available methodological

  17. Characteristic Time Scales of Transport Processes for Chemotactic Bacteria in Groundwater: Analysis of Pore-scale to Field-scale Experimental Data (United States)

    Ford, R. M.


    Many processes contribute to the transport of microorganisms in groundwater environments. One process of interest is chemotaxis, whereby motile bacteria are able to detect and swim toward increasing concentrations of industrial hydrocarbons that they perceive as food sources. By enabling bacteria to migrate to the sources of pollutants that they degrade, chemotaxis has the potential to enhance bioremediation efforts, especially in less permeable zones where contamination may persist. To determine the field conditions under which chemotaxis might be exploited in a bioremediation scheme requires an understanding of the characteristic time scales in the system. We defined a dimensionless chemotaxis number that compares the time over which a bacterial population is exposed to a chemical gradient to the time required for a bacterial population to migrate a significant distance in response to a chemical gradient. The exposure time and the response time are dependent upon the experimental conditions and properties of the bacteria and chemical attractant. Experimental data was analyzed for a range of groundwater flow rates over a wide scope of experimental systems including a single-pore with NAPL source, a microfluidic channel with and without a porous matrix, a laboratory column, a bench-scale microcosm and a field-scale study. Chemical gradients were created transverse to the flow direction. Distributions of chemotactic and nonchemotactic bacteria were compared to determine the extent of migration due to chemotaxis. Under some conditions at higher flow rates, the effect of chemotaxis was diminished to the point of not being detected. The goal of the study was to determine a critical value for the dimensionless chemotaxis number (which is independent of scale) that can be used as a design criterion to ascertain a priori the conditions under which a chemotactic response will impact bacterial transport relative to other processes such as advection and dispersion.

  18. Enhanced gypsum scaling by organic fouling layer on nanofiltration membrane: Characteristics and mechanisms. (United States)

    Wang, Jiaxuan; Wang, Lei; Miao, Rui; Lv, Yongtao; Wang, Xudong; Meng, Xiaorong; Yang, Ruosong; Zhang, Xiaoting


    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.

  19. Coupling atomistic and continuum length scales in heteroepitaxial systems: Multiscale molecular-dynamics/finite-element simulations of strain relaxation in Si/ Si3 N4 nanopixels (United States)

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


    A hybrid atomistic-continuum simulation approach has been implemented to study strain relaxation in lattice-mismatched Si/Si3N4 nanopixels on a Si(111) substrate. We couple the molecular-dynamics (MD) and finite-element simulation approaches to provide an atomistic description near the interface and a continuum description deep into the substrate, increasing the accessible length scales and greatly reducing the computational cost. The results of the hybrid simulation are validated against full multimillion-atom MD simulations. We find that strain relaxation in Si/Si3N4 nanopixels may occur through the formation of a network of interfacial domain boundaries reminiscent of interfacial misfit dislocations. They result from the nucleation of domains of different interfacial bonding at the free edges and corners of the nanopixel, and subsequent to their creation they propagate inwards. We follow the motion of the domain boundaries and estimate a propagation speed of about ˜2.5×103m/s . The effects of temperature, nanopixel architecture, and film structure on strain relaxation are also investigated. We find: (i) elevated temperature increases the interfacial domain nucleation rates; (ii) a thin compliant Si layer between the film and the substrate plays a beneficial role in partially suppressing strain relaxation; and (iii) additional control over the interface morphology may be achieved by varying the film structure.

  20. Investigation of the structure of human dental tissue at multiple length scales using high energy synchrotron X-ray SAXS/WAXS (United States)

    Sui, Tan; Landini, Gabriel; Korsunsky, Alexander M.


    High energy (>50keV) synchrotron X-ray scattering experiments were carried out on beamline I12 JEEP at the Diamond Light Source (DLS, Oxford, UK). Although a complete human tooth could be studied, in the present study attention was focused on coupons from the region of the Dentin-Enamel Junction (DEJ). Simultaneous high energy SAXS/WAXS measurements were carried out. Quantitative analysis of the results allows multiple length scale characterization of the nano-crystalline structure of dental tissues. SAXS patterns analysis provide insight into the mean thickness and orientation of hydroxyapatite particles, while WAXS (XRD) patterns allow the determination of the crystallographic unit cell parameters of the hydroxyapatite phase. It was found that the average particle thickness determined from SAXS interpretation varies as a function of position in the vicinity of the DEJ. Most mineral particles are randomly orientated within dentin, although preferred orientation emerges and becomes stronger on approach to the enamel. Within the enamel, texture is stronger than anywhere in the dentin, and the determination of lattice parameters can be accomplished by Pawley refinement of the multiple peak diffraction pattern. The results demonstrate the feasibility of using high energy synchrotron X-ray beams for the characterization of human dental tissues. This opens up the opportunity of studying thick samples (e.g., complete teeth) in complex sample environments (e.g., under saline solution). This opens new avenues for the application of high energy synchrotron X-ray scattering to dental research.

  1. 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)


    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.

  2. A Short Scale Length for the \\alpha-Enhanced Thick Disk of the Milky Way: Evidence from Low-Latitude SEGUE Data

    CERN Document Server

    Cheng, Judy Y; Morrison, Heather L; Lee, Young Sun; Beers, Timothy C; Bizyaev, Dmitry; Harding, Paul; Malanushenko, Elena; Malanushenko, Viktor; Oravetz, Daniel; Pan, Kaike; Schlesinger, Katharine J; Schneider, Donald P; Simmons, Audrey; Weaver, Benjamin A


    We examine the \\alpha-element abundance ratio, [\\alpha/Fe], of 5620 stars, observed by the Sloan Extension for Galactic Understanding and Exploration survey in the region 6 kpc < R < 16 kpc, 0.15 kpc < |Z| < 1.5 kpc, as a function of Galactocentric radius R and distance from the Galactic plane |Z|. Our results show that the high-\\alpha\\ thick disk population has a short scale length (L_thick ~ 1.8 kpc) compared to the low-\\alpha population, which is typically associated with the thin disk. We find that the fraction of high-\\alpha\\ stars in the inner disk increases at large |Z|, and that high-\\alpha\\ stars lag in rotation compared to low-\\alpha\\ stars. In contrast, the fraction of high-\\alpha\\ stars in the outer disk is low at all |Z|, and high- and low-\\alpha\\ stars have similar rotational velocities up to 1.5 kpc from the plane. We interpret these results to indicate that different processes were responsible for the high-\\alpha\\ populations in the inner and outer disk. The high-\\alpha\\ population...

  3. Multi-Length Scale-Enriched Continuum-Level Material Model for Kevlar®-Fiber-Reinforced Polymer-Matrix Composites (United States)

    Grujicic, M.; Pandurangan, B.; Snipes, J. S.; Yen, C.-F.; Cheeseman, B. A.


    Fiber-reinforced polymer matrix composite materials display quite complex deformation and failure behavior under ballistic/blast impact loading conditions. This complexity is generally attributed to a number of factors such as (a) hierarchical/multi-length scale architecture of the material microstructure; (b) nonlinear, rate-dependent and often pressure-sensitive mechanical response; and (c) the interplay of various intrinsic phenomena and processes such as fiber twisting, interfiber friction/sliding, etc. Material models currently employed in the computational engineering analyses of ballistic/blast impact protective structures made of this type of material do not generally include many of the aforementioned aspects of the material dynamic behavior. Consequently, discrepancies are often observed between computational predictions and their experimental counterparts. To address this problem, the results of an extensive set of molecular-level computational analyses regarding the role of various microstructural/morphological defects on the Kevlar® fiber mechanical properties are used to upgrade one of the existing continuum-level material models for fiber-reinforced composites. The results obtained show that the response of the material is significantly affected as a result of the incorporation of microstructural effects both under quasi-static simple mechanical testing condition and under dynamic ballistic-impact conditions.

  4. Hierarchical or not? Effect of the length scale and hierarchy of the surface roughness on omniphobicity of lubricant-infused substrates. (United States)

    Kim, Philseok; Kreder, Michael J; Alvarenga, Jack; Aizenberg, Joanna


    Lubricant-infused textured solid substrates are gaining remarkable interest as a new class of omni-repellent nonfouling materials and surface coatings. We investigated the effect of the length scale and hierarchy of the surface topography of the underlying substrates on their ability to retain the lubricant under high shear conditions, which is important for maintaining nonwetting properties under application-relevant conditions. By comparing the lubricant loss, contact angle hysteresis, and sliding angles for water and ethanol droplets on flat, microscale, nanoscale, and hierarchically textured surfaces subjected to various spinning rates (from 100 to 10,000 rpm), we show that lubricant-infused textured surfaces with uniform nanofeatures provide the most shear-tolerant liquid-repellent behavior, unlike lotus leaf-inspired superhydrophobic surfaces, which generally favor hierarchical structures for improved pressure stability and low contact angle hysteresis. On the basis of these findings, we present generalized, low-cost, and scalable methods to manufacture uniform or regionally patterned nanotextured coatings on arbitrary materials and complex shapes. After functionalization and lubrication, these coatings show robust, shear-tolerant omniphobic behavior, transparency, and nonfouling properties against highly contaminating media.

  5. Orbital and Physical Characteristics of Meter-scale Impactors from Airburst Observations

    CERN Document Server

    Brown, P; Clark, D; Tagliaferri, E


    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 ...

  6. Typical Structure, Variety, and Multi-Scale Characteristics of Meiyu Front

    Institute of Scientific and Technical Information of China (English)

    ZHENG Yonggunag; CHEN Jiong; GE Guoqing; ZHU Peijun


    Meiyu front plays an important role in summer rainfall in central China. Based on the GMS-5 satellite images, NCEP reanalyses (2.5°×2.5°) and final analyses (1°×1°) data, and meteorological conventional sounding observations, the horizontal and vertical structures of the Meiyu front were summarized using multiple diagnostic variables, including winds, temperature, jet stream, front, pseduo-equivalent potential temperature, divergence, vertical motion, static instability, etc. In this paper, four cases were selected and analyzed, two of which are in 26-28 June and 23 July 2002 during the Experiment on Iteavy Rain in the Meiyu period in the lower reaches of the Yangtze River, and the others are in May and July 1998. The two cases in July 1998 and July 2002 are the secondary Meiyu front cases. The results show that the structures and characteristics of the Meiyu front are different for various cases, or at various places and time, or at various stages of one case, and the frontal characteristics can be converted from the polar front to the equatorial front. Because of the interaction of the different scale circulations in the high and low latitudes, the horizontal structure of the Meiyu front has various forms. The results in this paper also show that the typical Meiyu front consists of a narrow band with a high gradient of potential equivalent temperature below 500 hPa, south of which is warm and moist air mass, and north of which is the transformed air mass from the midlatitude ocean or polar continent. Below the mid troposphere, south of the front blows southwesterlies, while north blows easterlies. The ascending motion and precipitation usually occur ahead of the Meiyu front. In the upper troposphere, the subtropical front is above the Meiyu front, but two fronts are separated. In addition, the upper westerly jet stream and the easterlies to the south of the Meiyu front result in the upper divergent flow field. The multi-scale characteristics of the

  7. Performance and slipstream characteristics of small-scale propellers at low Reynolds numbers (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

  8. Psychometric Characteristics of Croatian Version of the Daily Spiritual Experience Scale

    Directory of Open Access Journals (Sweden)

    Željko Rakošec


    Full Text Available Background: The Daily Spiritual Experience Scale (DSES has been developed through extensive and qualitative research. Numerous studies have confirmed the reliability and validity of the DSES among different populations. Most of the studies have shown association of the DSES with physical and psychological well-being. Purpose: The current study aimed to evaluate the psychometric properties of the DSES in the Croatian population. Method: The 16-item scale was translated through standard translation/back-translation procedures. The scale was afterwards applied to a sample of 535 test subjects (49% men and 51% women, mean age 42.6 years. Results: The coefficient of reliability (Cronbach alpha = 0.945 is very high. The coefficients of discriminant validity were satisfactory for 15 items, whereas only one item (14 has a coefficient of less than 0.30. The factor analysis after oblique rotation resulted in two related factors: the relationship with God and relationship with others. Using these two factors explained the 66.1% of the variance. Conclusion: Based on the data, it can be concluded that DSES has satisfactory psychometric characteristics and can be applied to the Croatian population, but its correlation with other religious and non-religious constructs should be verified in further research.

  9. 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


    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".

  10. Identification of characteristic ELM evolution patterns with Alfven-scale measurements and unsupervised machine learning analysis (United States)

    Smith, David R.; Fonck, R. J.; McKee, G. R.; Diallo, A.; Kaye, S. M.; Leblanc, B. P.; Sabbagh, S. A.


    Edge localized mode (ELM) saturation mechanisms, filament dynamics, and multi-mode interactions require nonlinear models, and validation of nonlinear ELM models requires fast, localized measurements on Alfven timescales. Recently, we investigated characteristic ELM evolution patterns with Alfven-scale measurements from the NSTX/NSTX-U beam emission spectroscopy (BES) system. We applied clustering algorithms from the machine learning domain to ELM time-series data. The algorithms identified two or three groups of ELM events with distinct evolution patterns. In addition, we found that the identified ELM groups correspond to distinct parameter regimes for plasma current, shape, magnetic balance, and density pedestal profile. The observed characteristic evolution patterns and corresponding parameter regimes suggest genuine variation in the underlying physical mechanisms that influence the evolution of ELM events and motivate nonlinear MHD simulations. Here, we review the previous results for characteristic ELM evolution patterns and parameter regimes, and we report on a new effort to explore the identified ELM groups with 2D BES measurements and nonlinear MHD simulations. Supported by U.S. Department of Energy Award Numbers DE-SC0001288 and DE-AC02-09CH11466.

  11. Microbial forensics: predicting phenotypic characteristics and environmental conditions from large-scale gene expression profiles.

    Directory of Open Access Journals (Sweden)

    Minseung Kim


    Full Text Available A tantalizing question in cellular physiology is whether the cellular state and environmental conditions can be inferred by the expression signature of an organism. To investigate this relationship, we created an extensive normalized gene expression compendium for the bacterium Escherichia coli that was further enriched with meta-information through an iterative learning procedure. We then constructed an ensemble method to predict environmental and cellular state, including strain, growth phase, medium, oxygen level, antibiotic and carbon source presence. Results show that gene expression is an excellent predictor of environmental structure, with multi-class ensemble models achieving balanced accuracy between 70.0% (±3.5% to 98.3% (±2.3% for the various characteristics. Interestingly, this performance can be significantly boosted when environmental and strain characteristics are simultaneously considered, as a composite classifier that captures the inter-dependencies of three characteristics (medium, phase and strain achieved 10.6% (±1.0% higher performance than any individual models. Contrary to expectations, only 59% of the top informative genes were also identified as differentially expressed under the respective conditions. Functional analysis of the respective genetic signatures implicates a wide spectrum of Gene Ontology terms and KEGG pathways with condition-specific information content, including iron transport, transferases, and enterobactin synthesis. Further experimental phenotypic-to-genotypic mapping that we conducted for knock-out mutants argues for the information content of top-ranked genes. This work demonstrates the degree at which genome-scale transcriptional information can be predictive of latent, heterogeneous and seemingly disparate phenotypic and environmental characteristics, with far-reaching applications.

  12. Microbial forensics: predicting phenotypic characteristics and environmental conditions from large-scale gene expression profiles. (United States)

    Kim, Minseung; Zorraquino, Violeta; Tagkopoulos, Ilias


    A tantalizing question in cellular physiology is whether the cellular state and environmental conditions can be inferred by the expression signature of an organism. To investigate this relationship, we created an extensive normalized gene expression compendium for the bacterium Escherichia coli that was further enriched with meta-information through an iterative learning procedure. We then constructed an ensemble method to predict environmental and cellular state, including strain, growth phase, medium, oxygen level, antibiotic and carbon source presence. Results show that gene expression is an excellent predictor of environmental structure, with multi-class ensemble models achieving balanced accuracy between 70.0% (±3.5%) to 98.3% (±2.3%) for the various characteristics. Interestingly, this performance can be significantly boosted when environmental and strain characteristics are simultaneously considered, as a composite classifier that captures the inter-dependencies of three characteristics (medium, phase and strain) achieved 10.6% (±1.0%) higher performance than any individual models. Contrary to expectations, only 59% of the top informative genes were also identified as differentially expressed under the respective conditions. Functional analysis of the respective genetic signatures implicates a wide spectrum of Gene Ontology terms and KEGG pathways with condition-specific information content, including iron transport, transferases, and enterobactin synthesis. Further experimental phenotypic-to-genotypic mapping that we conducted for knock-out mutants argues for the information content of top-ranked genes. This work demonstrates the degree at which genome-scale transcriptional information can be predictive of latent, heterogeneous and seemingly disparate phenotypic and environmental characteristics, with far-reaching applications.

  13. Mechanically stable nanostructures with desirable characteristic field enhancement factors: a response from scale invariance in electrostatics (United States)

    de Assis, Thiago A.; Dall'Agnol, Fernando F.


    This work presents an accurate numerical study of the electrostatics of a system formed by individual nanostructures mounted on support substrate tips, which provides a theoretical prototype for applications in field electron emission or for the construction of tips in probe microscopy that requires high resolution. The aim is to describe the conditions to produce structures mechanically robust with desirable field enhancement factor (FEF). We modeled a substrate tip with a height h 1, radius r 1 and characteristic FEF {γ }1, and a top nanostructure with a height h 2, radius {r}2\\lt {r}1 and FEF {γ }2, for both hemispheres on post-like structures. The nanostructure mounted on the support substrate tip then has a characteristic FEF, {γ }{{C}}. Defining the relative difference {η }{{R}}=({γ }{{C}}-{γ }1)/({γ }3-{γ }1), where {γ }3 corresponds to the reference FEF for a hemisphere of the post structure with a radius {r}3={r}2 and height {h}3={h}1+{h}2, our results show, from a numerical solution of Laplace’s equation using a finite element scheme, a scaling {η }{{R}}=f(u\\equiv λ {θ }-1), where λ \\equiv {h}2/{h}1 and θ ={r}1/{r}2. Given a characteristic variable u c, for u\\ll {u}{{c}}, we found a power law {η }{{R}}˜ {u}κ , with κ ≈ 0.55. For u\\gg {u}{{c}}, {η }{{R}}\\to 1, which led to conditions where {γ }{{C}}\\to {γ }3. As a consequence of scale invariance, it is possible to derive a simple expression for {γ }{{C}} and to predict the conditions needed to produce related systems with a desirable FEF that are robust owing to the presence of the substrate tip. Finally, we discuss the validity of Schottky’s conjecture (SC) for these systems, showing that, while to obey SC is indicative of scale invariance, the opposite is not necessarily true. This result suggests that a careful analysis must be performed before attributing SC as an origin of giant FEF in experiments.

  14. Substorm and Magnetosphere Characteristic Scales Inferred from the SuperMAG Auroral Electrojet Indices (United States)

    Newell, P.; Gjerloev, J.


    A generalization of the traditional 12-station auroral electrojet index, AE, to include more than 100 magnetometer stations, SME, is an excellent predictor of global auroral power, even at high cadence (1-min). We use this index, and a data base of more than 53,000 substorms derived from it, covering 1980-2009, to investigate time and energy scales in the magnetosphere, during substorms and otherwise. We find, contrary to common opinion, that substorms do not have a preferred recurrence rate, but instead have two distinct dynamic regimes, each following a power law. The number of substorms recurring after a time Δt, N(Δt), varies as Δt -1.19 for short times (3 hr). Other evidence also shows these distinct regimes for the magnetosphere, including a break in the power law spectra for SME at about 3 h. The time between two consecutive substorms is only weakly correlated (r=0.18 for isolated and r=0.06 for recurrent) with the time until the next, suggesting quasi-periodicity is not common. However substorms do have a preferred size, with the typical peak SME magnitude reaching 400-600 nT, but with a mean of 656 nT, corresponding to a bit less than 40 GW auroral power. More surprisingly, another characteristic scale exists in the magnetosphere, namely a peak in the SME distribution around 61 nT, corresponding to about 5 GW precipitating auroral power. The dominant form of auroral precipitation is diffuse aurora, thus these values are properties of the magnetotail thermal electron distribution. The characteristic 5 GW value specifically represents a preferred minimum below which the magnetotail rarely drops. The magnetotail experiences continuous loss by precipitation, so the existence of a preferred minimum implies driving which rarely disappears altogether. Finally, the distribution of SME values across all times, in accordance with earlier work on AE, is best fit by the sum of two distributions, each normal in log(SME). The lower distribution (with a 40% weighting

  15. 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


    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...

  16. Flow characteristics and micro-scale metallic particle formation in the laser supersonic heating technique (United States)

    Lin, Shih-Lung; Lin, Jehnming


    The characteristics of the supersonic flow of the laser heating technique for producing micro-scale metallic particles were investigated in this study. A numerical model was established to predict the flow fields and particle trajectories leaving a spray nozzle with shock wave effects. The compressible flow of the shock waves and the trajectories of particles in diameters of 1-20 μm were simulated and compared with the flow visualization. In the experiment, a pulsed Nd-YAG laser was used as heat source on a carbon steel target within the nozzle, and the carbon steel particles were ejected by high-pressure air. The result shows that the shock wave structures were generated at various entrance pressures, and there is a significant increase in the amount of carbon steel particles and the spraying angles by increasing the entrance air pressure.

  17. In-silico experiments on characteristic time scale at a shear-free gas-liquid interface in fully developed turbulence (United States)

    Nagaosa, Ryuichi; Handler, Robert A.


    The purpose of this study is to model scalar transfer mechanisms in a fully developed turbulence for accurate predictions of the turbulent scalar flux across a shear-free gas-liquid interface. The concept of the surface-renewal approximation (Dankwerts, 1951) is introduced in this study to establish the predictive models for the interfacial scalar flux. Turbulent flow realizations obtained by a direct numerical simulation technique are employed to prepare details of three-dimensional information on turbulence in the region very close to the interface. Two characteristic time scales at the interface have been examined for exact prediction of the scalar transfer flux. One is the time scale which is reciprocal of the root-mean-square surface divergence, Tγ = langleγγrangle-1/2, where γ is the surface divergence. The other time scale to be examined is TS = Λ/V, where Λ is the zero-correlation length of the surface divergence as the interfacial length scale, and V is the root-mean-square velocity fluctuation in the streamwise direction as the interfacial velocity scale. The results of this study suggests that Tγ is slightly unsatisfactory to correlate the turbulent scalar flux at the gas-liquid interface based on the surface-renewal approximation. It is also found that the proportionality constant appear to be 0.19, which is different with that observed in the laboratory experiments, 0.34 (Komori, Murakami, & Ueda, 1989). It is concluded that the time scale, Tγ, is considered a different kind of the time scale observed in the laboratory experiments. On the other hand, the present in-silico experiments indicate that Ts predicts the turbulent scalar flux based on the surface-renewal approximation in a satisfactory manner. It is also elucidated that the proportionality constant for Ts is approximately 0.36, which is very close to that found by the laboratory experiments. This fact shows that the time scale Ts appears to be essentially the same as the time scale the

  18. 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: [State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, 430074 (China)


    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.

  19. Evaporation characteristics of thin film liquid argon in nano-scale confinement: A molecular dynamics study (United States)

    Hasan, Mohammad Nasim; Shavik, Sheikh Mohammad; Rabbi, Kazi Fazle; Haque, Mominul


    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.

  20. Scaling Characteristics of Developing Sea Breezes Simulated in a Water Tank (United States)

    Yuan, Renmin; Sun, Jianning; Luo, Tao; Wu, Xuping


    Sea-breeze circulations in a stably stratified environment have been simulated in a water tank. The floor of the tank was divided into two halves representing land and sea; the land side was heated from the bottom of the tank, and the sea side was insulated by an underlying sponge slab. The temperature profiles over both land and sea sides, the land-sea temperature difference, and the horizontal temperature distributions were measured. Particle tracking velocimetry was applied to obtain the two-dimensional velocity field orthogonal to the coastline. It was shown that the overall flow consists of a closed circulation caused by the horizontal temperature difference between land and sea, and a strong updraft occurring at the sea-breeze front. The dimensionless governing parameters are calculated from the measurements and used to characterize the developing sea breezes. The analysis confirms the scaling laws for sea-breeze velocity and depth. The results indicate that the scaling characteristics of the sea-breeze translation speed during the developing period are different to those during the following maintaining period. A criterion for the onset of the sea breeze is proposed based on these results.

  1. 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


    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.

  2. The analysis of large-scale turbulence characteristics in the Indonesian seas derived from a regional model based on the Princeton Ocean Model

    Directory of Open Access Journals (Sweden)

    K. O'Driscoll


    Full Text Available The analysis is presented of the distribution of deep ocean turbulence characteristics on the horizontal scale of order 100 km in the vicinity of the Lifamatola Sill, from the Southern Maluku Sea (north of the sill to the Seram Sea (south of the sill. The turbulence characteristics were calculated with a regional model of the Indonesian seas circulation based on the Princeton Ocean Model (POM, incorporating the Mellor-Yamada turbulence closure scheme. The analysis has been carried out for the entire Indonesian seas region, including areas around important topographic features, such as the Lifamatola Sill, the North Sangihe Ridge, the Dewakang Sill and the North and South Halmahera Sea Sills. To illustrate results of application of the Mellor-Yamada closure scheme we have focused on the description of features of turbulence characteristics across the Lifamatola Sill because dynamically this region is very important and some estimates of mixing coefficients in this area are available. As is well known, the POM model output provides both dynamical (depth-integrated and 3-D velocities, temperature, salinity, and sea-surface-height and turbulence characteristics (kinetic energy and master scale of turbulence, mixing coefficients of momentum, temperature and salinity, etc.. As a rule, the analysis of POM modeling results has been restricted to the study of corresponding dynamical characteristics, however the study of turbulence characteristics is essential to understanding the dynamics of the ocean circulation as well. Due to the absence of direct measurements of turbulence characteristics in the analyzed area, we argued the validity of the simulated characteristics in the light of their compatibility with some general principles. Thus, along these lines, vertical profiles of across-the-sill velocities, twice the kinetic energy of turbulence, turbulence length scale, the separate terms in the equation of kinetic energy of turbulence, the Richardson

  3. Characteristics of Gaseous Carbon Emission from a Tropical Peatland Fire: A Plot-Scale Field Experiment in Central Kalimantan, Indonesia (United States)

    Hamada, Y.; Darung, U.; Limin, S. H.; Hatano, R.


    Tropical peatland in Southeast Asia is a vast reservoir of terrestrial carbon, which covers 24.8 million hectares and stores 68.5 PgC peat, equal to 11-14% of global peat carbon. In recent decades, large scale peatland fire has occurred frequently in that region, in which many areas of peatland were reclaimed with intention to use the land for forest plantation and rice paddy. We conducted a plot-scale peat burning experiment to elucidate the characteristics of gaseous carbon emission from a tropical peatland fire at the ground level. The experimental site was established at an open area 20 km southeast from Palangka Raya, Central Kalimantan Province, Indonesia. The size of the burning plot is 4 m in length and 3 m in width. Gas samples were collected at heights of 1.0, 0.5, 0.0 (aboveground), -0.1 and -0.2 m (belowground) through stainless steel and/or aluminum tubes settled across the edge of the plot. The concentrations of carbon dioxide (CO2), carbon monoxide (CO), methane (CH4) and particulate matter (PM) was determined. Soil temperature was recorded every 10 minutes 0.1 and 0.2 m below the ground surface. Twelve iron rods were installed in 1-m by 1-m square grid to determine the depth of burn scar. After ignition, flaming stage of peat burning was ceased within 1-2 hours. The following smoldering stage continued for a week. In the flaming stage, soil temperature at -0.1 m increased tentatively. After the smoldering stage began, the temperature rapidly increased to 350-450°C. Response of soil temperature at -0.2 m was less prominent. Concentrations of gaseous components became maximal in the flaming stage. During the smoldering stage, the concentrations gradually decreased. The influence of burning on CO2 and PM was prominently remained at -0.1 m, whereas those at -0.2 m were not so much. The averaged burnt depth was 5.8±5.1 cm. Based on bulk density of 0.22 g/cm3 and carbon content of 55.5%, the amount of carbon lost from the plot was 85.3 kg. Most of the

  4. Three-Dimensional Simulation of SOFC Anode Polarization Characteristics Based on Sub-Grid Scale Modeling of Microstructure



    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...

  5. Understanding I/O workload characteristics of a Peta-scale storage system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Youngjae [ORNL; Gunasekaran, Raghul [ORNL


    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.

  6. Descriptive Characteristics and Initial Psychometric Properties of the Non-Suicidal Self-Injury Disorder Scale. (United States)

    Victor, Sarah E; Davis, Tchiki; Klonsky, E David


    Non-suicidal self-injury (NSSI) is highly prevalent and associated with tissue damage, emotional distress, and psychiatric disorders. While often discussed in the context of Borderline Personality Disorder and suicide, research demonstrates that NSSI is distinct from these constructs and should be viewed as an independent diagnostic category. Recently, Non-Suicidal Self-Injury Disorder (NSSID) was included in the revised Diagnostic and Statistical Manual of Mental Disorders as a condition for further study. In this article, we describe the properties of a self-report measure designed to assess proposed criteria for NSSID. Undergraduate students at 2 large, public universities completed the NSSID Scale (NSSIDS) along with other measures of NSSI characteristics and psychopathology. Among participants with a history of NSSI, approximately half (54.55%) met diagnostic criteria for NSSID. Participants were most frequently excluded from an NSSID diagnosis on the basis of criterion A (frequency of NSSI) and criterion E (distress or impairment related to NSSI), while participants were least likely to be excluded from diagnosis on the basis of criterion D (NSSI method exclusions) and criterion F (diagnostic "rule-outs"). Consistent with previous literature, the most commonly reported precipitants to NSSI were negative feelings or thoughts (criterion C2). Participants who met criteria for NSSID reported more severe depression, anxiety, and NSSI than participants who engaged in NSSI but did not meet criteria for NSSID. These results support the use of the NSSIDS as a reliable and valid self-report measure of NSSID symptoms.

  7. Aerodynamic characteristics of a large-scale hybrid upper surface blown flap model having four engines (United States)

    Carros, R. J.; Boissevain, A. G.; Aoyagi, K.


    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.

  8. Tracking Particulate Organic Matter Characteristics in Major Arctic Rivers: Indicators of Watershed-Scale Climate Impacts (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.


    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.

  9. Effect of nano-scale characteristics of graphene on electrochemical performance of activated carbon supercapacitor electrodes (United States)

    Jasni, M. R. M.; Deraman, M.; Suleman, M.; Hamdan, E.; Sazali, N. E. S.; Nor, N. S. M.; Shamsudin, S. A.


    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.

  10. Investigation of estimating accuracy for aerodynamic characteristics of a scaled supersonic experimental airplane using IMU data based on flight simulation



    This paper describes a pre-flight estimation method for aerodynamic characteristics and investigates the accuracy of the estimated aerodynamic characteristics of the scaled supersonic experimental airplane, using IMU (Inertial Measurement Unit) data obtained in a flight simulation. The results demonstrate that the required accuracy is not achieved and that the main sources of error are in the estimation of dynamic pressure, misalignment between the body axis and IMU chassis axis, and IMU disc...

  11. 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: [Department of Materials Science and Engineering, Indian Institute of Technology, Kanpur 208016 (India)


    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.

  12. Influence of polyethylene glycol chain length on compatibility and release characteristics of ternary solid dispersions of itraconazole in polyethylene glycol/hydroxypropylmethylcellulose 2910 E5 blends. (United States)

    Janssens, Sandrien; Denivelle, Samgar; Rombaut, Patrick; Van den Mooter, Guy


    The present study aims to elucidate the influence of the polyethylene glycol chain length on the miscibility of PEG/HPMC 2910 E5 polymer blends, the influence of polymer compatibility on the degree of molecular dispersion of itraconazole, and in vitro dissolution. PEG 2000, 6000, 10,000 and 20,000 were included in the study. Solid dispersions were prepared by spray drying and characterized with MDSC, XRPD and in vitro dissolution testing. The polymer miscibility increased with decreasing chain length due to a decrease in the Gibbs free energy of mixing. Recrystallization of itraconazole occurred as soon as a critical temperature of ca. 75 degrees C was reached for the glass transition that represents the ternary amorphous phase. Due to the lower miscibility degree between the longer PEG types and HPMC 2910 E5, the ternary amorphous phase was further separated, leading to a more rapid decrease of the ternary amorphous phase glass transition as a function of PEG and itraconazole weight percentage and hence, itraconazole recrystallization. In terms of release, an advantage of the shorter chain length PEG types (2000, 6000) over the longer chain length PEG types (10,000, 20,000) was observed for the polymer blends with 5% of PEG with respect to the binary itraconazole/HPMC 2910 E5 solid dispersion. Among the formulations with a 15/85 (w/w) PEG/HPMC 2910 E5 ratio on the other hand, there was no difference in the release profile.

  13. Myofascial force transmission is increasingly important at lower forces: firing frequency-related length-force characteristics of rat extensor digitorum longus

    NARCIS (Netherlands)

    Meijer, H.J.M; Baan, G.C.; Huijing, P.A.


    Aim: Effects of submaximal stimulation frequencies on myofascial force transmission were investigated for rat anterior crural muscles with all motor units activated. - Methods: Tibialis anterior and extensor hallucis longus (TAEHL) muscles were kept at constant muscle-tendon complex length, but exte

  14. Dynamic Single-Use Bioreactors Used in Modern Liter- and m(3)- Scale Biotechnological Processes: Engineering Characteristics and Scaling Up. (United States)

    Löffelholz, Christian; Kaiser, Stephan C; Kraume, Matthias; Eibl, Regine; Eibl, Dieter


    During the past 10 years, single-use bioreactors have been well accepted in modern biopharmaceutical production processes targeting high-value products. Up to now, such processes have mainly been small- or medium-scale mammalian cell culture-based seed inoculum, vaccine or antibody productions. However, recently first attempts have been made to modify existing single-use bioreactors for the cultivation of plant cells and tissue cultures, and microorganisms. This has even led to the development of new single-use bioreactor types. Moreover, due to safety issues it has become clear that single-use bioreactors are the "must have" for expanding human stem cells delivering cell therapeutics, the biopharmaceuticals of the next generation. So it comes as no surprise that numerous different dynamic single-use bioreactor types, which are suitable for a wide range of applications, already dominate the market today. Bioreactor working principles, main applications, and bioengineering data are presented in this review, based on a current overview of greater than milliliter-scale, commercially available, dynamic single-use bioreactors. The focus is on stirred versions, which are omnipresent in R&D and manufacturing, and in particular Sartorius Stedim's BIOSTAT family. Finally, we examine development trends for single-use bioreactors, after discussing proven approaches for fast scaling-up processes.

  15. Effects of dune stabilization on vegetation characteristics and soil properties at multiple scales in Horqin Sandy Land, Northern China

    Institute of Scientific and Technical Information of China (English)

    XiaoAn Zuo; XueYong Zhao; ShaoKun Wang; Xin Zhou; Peng Lv; Jing Zhang


    Ecological patterns and processes in dune ecosystems have been a research focus in recent years, however information on how dune stabilization influences vegetation and soil at different spatial scales is still lacking. In this study, we measured vegetation characteristics and soil properties across three spatial scales (10, 100 and 1,000 m2) along gradient dune stabi-lization stages (mobile dune, semi-fixed dune and fixed dune) in Horqin Sandy Land, Northern China. Vegetation cover over all scales significantly increased with degree of dune stabilization, as well as species richness and C/N ratio at 10 m2 scale. Species richness significantly increased with the increase in measured scales at each stage of dune stabilization and was higher in fixed dune than that in mobile dune and semi-fixed dune at 100 and 1,000 m2 scales. Over all scales, aboveground biomass was lower in mobile dune than that in semi-fixed dune and fixed dune, and soil organic C, total N, EC, very fine sand and silt+clay contents were higher in fixed dune than those in mobile dune and semi-fixed dune. These results suggest that along the gradient dune stabilization, species richness has strong spatial scale-dependence, but vege-tation cover, aboveground biomass and soil properties is generally scale independent (i.e., the pattern of response is con-sistent across all scales). Effect of dune stabilization on vegetation and soil over all spatial scales results in the positive correlation among vegetation cover, species richness, biomass, soil organic C, total N, C/N, EC, very fine sand and silt+clay along the gradient dune stabilization. In addition, species richness at the smallest scale (10 m2) has more sensitive response to dune stabilization. Thus, the monitoring strategies at small scales are essential to detect changes of species diversity in semiarid dune ecosystems.

  16. Reliability and Characteristics of Wafer-Level Chip-Scale Packages under Current Stress (United States)

    Chen, Po-Ying; Kung, Heng-Yu; Lai, Yi-Shao; Hsiung Tsai, Ming; Yeh, Wen-Kuan


    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.

  17. Scale-Up of flat plate photobioreactors considering diffuse and direct light characteristics. (United States)

    Quinn, Jason C; Turner, Chris W; Bradley, Thomas H


    This study investigates the scaling of photobioreactor productivity based on the growth of Nannochloropsis salina incorporating the effects of direct and diffuse light. The scaling and optimization of photobioreactor geometry was analyzed by determining the growth response of a small-scale system designed to represent a core sample of a large-scale photobioreactor. The small-scale test apparatus was operated at a variety of light intensities on a batch time scale to generate a photosynthetic irradiance (PI) growth dataset, ultimately used to inform a PI growth model. The validation of the scalability of the PI growth model to predict productivity in large-scale systems was done by comparison with experimental growth data collected from two geometrically different large-scale photobioreactors operated at a variety of light intensities. For direct comparison, the small-scale and large-scale experimental systems presented were operated similarly and in such a way to incorporate cultivation relevant time scales, light intensities, mixing, and nutrient loads. Validation of the scalability of the PI growth model enables the critical evaluation of different photobioreactor geometries and design optimization incorporating growth effects from diffuse and direct light. Discussion focuses on the application of the PI growth model to assess the effect of diffuse light growth compared to direct light growth for the evaluation of photobioreactors followed by the use of the model for photobioreactor geometry optimization on the metric of areal productivity.

  18. An Outlook on Agricultural Modernization Path with Chinese Characteristics from Scale Agricultural Operation

    Institute of Scientific and Technical Information of China (English)

    Wanjiang; WANG


    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 agricultural products and promoting the progress in agricultural science and technology comprehensively.

  19. 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


    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.

  20. Unipolar resistive switching characteristics and scaling behaviors in La2Mo2O9 thin films for nonvolatile memory applications (United States)

    Hu, L.; Lin, G. T.; Luo, X.; Wei, R. H.; Zhu, X. B.; Song, W. H.; Dai, J. M.; Sun, Y. P.


    La2Mo2O9 (LMO) thin films have been deposited on Pt/Ti/SiO2/Si substrates by pulsed laser deposition and the resistive switching (RS) characteristics of the Au/LMO/Pt devices has been investigated. The Au/LMO/Pt devices show excellent unipolar RS characteristics with high resistance ratio between high resistance state and low resistance state (LRS), good endurance, and retention performances. The results of temperature dependence of resistance and x-ray photoelectron spectroscopy suggest that the observed RS characteristics can be explained by the formation and rupture of conducting filaments composed of oxygen vacancies. Furthermore, the plot of the reset current (IR) as a function of the third harmonic coefficient (B0) caused by Joule heating during the reset process shows scaling behavior with a power law of I R ∝ B0 - δ . The IR and reset power (PR) can also be scaled to the resistance in LRS (R0), i.e., I R ( P R ) ∝ R0 - α ( β ) . The observed scaling behaviors indicate the importance of the Joule heating for the RS characteristics of Au/LMO/Pt devices. These results demonstrate the potential application of LMO thin film in a nonvolatile memory device.

  1. Scaling through pair-wise comparison method in required characteristics of students applying for post graduate programs

    Directory of Open Access Journals (Sweden)

    Nese Güler


    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

  2. 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


    The Revised Danish Learning Styles Inventory (R-D-LSI) (Nielsen 2005), which is an adaptation of Sternberg- Wagner Thinking Styles Inventory (Sternberg, 1997), comprises 14 subscales, each measuring a separate learning style. Of these 14 subscales, 9 are eight items long and 5 are seven items long...... 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...

  3. 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


    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.

  4. Characteristic Scales of Baryon Acoustic Oscillations from Perturbation Theory: Non-linearity and Redshift-Space Distortion Effects

    CERN Document Server

    Nishimichi, Takahiro; Nakamichi, Masashi; Taruya, Atsushi; Yahata, Kazuhiro; Shirata, Akihito; Saito, Shun; Nomura, Hidenori; Yamamoto, Kazuhiro; Suto, Yasushi


    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. The resulting shifts are indeed sensitive to different choices of the definition of the BAO scale, which needs to be kept in mind in the data analysis. We present a toy model to explain the physical behavior of the shifts. We find that the BAO scale defined as in Percival et al. (2007) indeed shows very small shifts ($\\lesssim$ 1%) relative to the prediction in {\\it linear theory} in real space. The shifts can be predicted accurately for scales where the perturbation theory is reliable.

  5. Career Adapt-Abilities Scale-Belgium Form: psychometric characteristics and construct validity

    NARCIS (Netherlands)

    Dries, N.; van Esbroeck, R.; van Vianen, A.E.M.; de Cooman, R.; Pepermans, R.


    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 su

  6. Flux saturation length of sediment transport. (United States)

    Pähtz, Thomas; Kok, Jasper F; Parteli, Eric J R; Herrmann, Hans J


    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 Ls, which characterizes the flux response to a change in transport conditions. Here we derive, for the first time, an expression predicting Ls as a function of the average sediment velocity under different physical environments. Our expression accounts for both the characteristics of sediment entrainment and the saturation of particle and fluid velocities, and has only two physical parameters which can be estimated directly from independent experiments. We show that our expression is consistent with measurements of Ls in both aeolian and subaqueous transport regimes over at least 5 orders of magnitude in the ratio of fluid and particle density, including on Mars.

  7. Electrical Characteristics, Electrode Sheath and Contamination Layer Behavior of a Meso-Scale Premixed Methane-Air Flame Under AC/DC Electric Fields

    Institute of Scientific and Technical Information of China (English)

    CHEN Qi; YAN Limin; ZHANG Hao; LI Guoxiu


    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 magnitnde 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 indicatcd a complex effect of the collisiou 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.

  8. Characteristic time scales of coalescence of silver nanocomposite and nanoparticle films induced by continuous wave laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Paeng, Dongwoo; Grigoropoulos, Costas P., E-mail: [Department of Mechanical Engineering, University of California Berkeley, Berkeley, California 94720-1740 (United States); Lee, Daeho [Department of Mechanical Engineering, Gachon University, Seongnam-si, Gyeonggi-do 461-701 (Korea, Republic of)


    In-situ optical probing has been performed to analyze and compare the characteristic coalescence time scales of silver ion-doped polyvinylalcohol nanocomposite (Ag-PVA NC) and polyvinylpyrrolidone-capped silver nanoparticle (Ag-PVP NP) films subjected to continuous wave laser irradiation. The Ag-PVA NC yielded conductive metallic patterns by photothermal reduction of PVA, formation of nanoparticles from silver ions and their subsequent coalescence. On the other hand, Ag-PVP NP thin films produced conductive patterns through only coalescence of nanoparticles. Upon laser irradiation, Ag-PVA NC and Ag-PVP NP films exhibited different coalescence characteristics.

  9. Flow Scales of Influence on the Settling Velocities of Particles with Varying Characteristics (United States)

    Jacobs, Corrine N.; Merchant, Wilmot; Jendrassak, Marek; Limpasuvan, Varavut; Gurka, Roi; Hackett, Erin E.


    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

  10. Two-phase flow characteristics during flow boiling of halocarbon refrigerants in micro-scale channels

    Energy Technology Data Exchange (ETDEWEB)

    Arcanjo, Alexandre A.; Freitas, Juliano O.; Tibirica, Cristiano B.; Ribatski, Gherhardt [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Escola de Engenharia. Dept. de Engenharia Mecanica


    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/m{sup 2}s 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)

  11. Characteristics of oxide scale formed on Cu-bearing austenitic stainless steel during early stages of high temperature oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Swaminathan, Srinivasan, E-mail: [Metallurgy & Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 136 791 (Korea, Republic of); Krishna, Nanda Gopala [Metallurgy & Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Kim, Dong-Ik, E-mail: [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seongbuk-gu, Seoul 136 791 (Korea, Republic of)


    Highlights: • Initial oxidation characteristics of Cu-bearing austenitic stainless steel at 650 °C were studied. • Strong segregation and oxidation of Mn and Nb were found in the entire oxide scale. • Surface coverage by metallic Cu-rich precipitates increases with exposure time. • Chemical heterogeneity of oxide scale revealed initial oxidation to be non-selective. • Fe-Cr and Mn-Cr mixed oxides were realized along with binary oxides of Fe, Cr and Mn. - Abstract: 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 FeCr{sub 2}O{sub 4} and MnCr{sub 2}O{sub 4} 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.

  12. Characteristics of the Eysenck Personality Questionnaire Lie Scale and of Extreme Lie Scorers. (United States)

    Loo, Robert


    Results of statistical analyses suggest that high lie-scorers respond honestly, and that the Lie Scale for the Eysenck Personality Inventory may reflect a personality dimension of interest rather than an extraneous and undesirable factor to be eliminated. (Author)

  13. Characteristics of Patients with an Abnormal Glasgow Coma Scale in the Prehospital Setting

    Directory of Open Access Journals (Sweden)

    Durant, Edward


    Full Text Available Objective: This cross-sectional study describes the characteristics of patients with an abnormal Glasgow Coma Scale (GCS in the prehospital setting.Methods: We reviewed existing prehospital care reports (PCRs in the San Mateo County, California, emergency medical services (EMS database from January 1 to December 31, 2007. Adults age 18 or greater with a documented GCS fit inclusion criteria. We excluded single and multisystem trauma patients, as well as patients in cardiac arrest, respiratory arrest, or listed as deceased from the study. We classified the remaining patients as a normal GCS of 15 or abnormal (defined as less than 15 at any time during paramedic contact, and then further sub-classified into mild (GCS 13-14, moderate (GCS 9-12 or severe (GCS 3-8.Results: Of the 12,235 unique prehospital care record in the database, 9,044 (73.9% met inclusion criteria, comprised of 2,404 (26.6% abnormal GCS patients and 6,640 (73.4% normal GCS patients. In the abnormal GCS category, we classified 1,361 (56.6% patients as mild, 628 (26.1% as moderate, and 415 (17.3% as severe. Where sex was recorded, we identified 1,214 (50.5% abnormal GCS patients and 2,904 (43.7% normal GCS patients as male. Mean age was 65.6 years in the abnormal GCS group and 61.4 in the normal GCS group (p<0.0001. Abnormal GCS patients were more likely to have a history of conditions known to be associated, such as alcohol abuse (odds ratio [OR] 2.3, 95% confidence interval [CI]=2.75-3.00, diabetes (OR 1.34, 95% CI=1.17-1.54, substance abuse (OR 1.6, CI=1.09-2.3, stroke/transient ischemic attack (OR 2.0, CI=1.64-2.5, and seizures (OR 3.0, CI=1.64-2.5. Paramedics established intravenous (IV access on 1,821 (75.7%, OR 1.94, CI=1.74-2.2 abnormal GCS patients and administered medications to 777 (32.3%, OR 1.01, CI=0.92-1.12. Compared to patients with normal GCS, patients with a mildly abnormal GCS were less likely to receive medications (OR 0.61, CI=0.53-0.70 while those with a

  14. Experimental investigation of the wake characteristics of flow-powered and motorized laboratory-scale wind turbines (United States)

    Araya, Daniel; Dabiri, John


    We present experimental data that compares the wake characteristics of a laboratory-scale vertical-axis turbine while it is either powered by the flow or by a DC motor. This distinction is relevant for laboratory experiments in which scale turbine models are used that require the use of a motor to spin the turbine blades. Particle image velocimetry is used to measure the velocity field in a two-dimensional plane normal to the axis of rotation. This velocity field is then used to compare time-averaged streamwise velocity, turbulence kinetic energy, and power of the two configurations. The results give insight into the kinematic effect of adding energy to the flow by way of the motor, and they suggest limits on the extrapolation of laboratory results to full-scale performance. This work was supported by an NSF Graduate Research Fellowship to D.B.A and funding to J.O.D. from ONR N000141211047.

  15. Universality of modulation length and time exponents. (United States)

    Chakrabarty, Saurish; Dobrosavljević, Vladimir; Seidel, Alexander; Nussinov, Zohar


    We study systems with a crossover parameter λ, such as the temperature T, which has a threshold value λ(*) across which the correlation function changes from exhibiting fixed wavelength (or time period) modulations to continuously varying modulation lengths (or times). We introduce a hitherto unknown exponent ν(L) characterizing the universal nature of this crossover and compute its value in general instances. This exponent, similar to standard correlation length exponents, is obtained from motion of the poles of the momentum (or frequency) space correlation functions in the complex k-plane (or ω-plane) as the parameter λ is varied. Near the crossover (i.e., for λ→λ(*)), the characteristic modulation wave vector K(R) in the variable modulation length "phase" is related to that in the fixed modulation length "phase" q via |K(R)-q|[proportionality]|T-T(*)|(νL). We find, in general, that ν(L)=1/2. In some special instances, ν(L) may attain other rational values. We extend this result to general problems in which the eigenvalue of an operator or a pole characterizing general response functions may attain a constant real (or imaginary) part beyond a particular threshold value λ(*). We discuss extensions of this result to multiple other arenas. These include the axial next-nearest-neighbor Ising (ANNNI) model. By extending our considerations, we comment on relations pertaining not only to the modulation lengths (or times), but also to the standard correlation lengths (or times). We introduce the notion of a Josephson time scale. We comment on the presence of aperiodic "chaotic" modulations in "soft-spin" and other systems. These relate to glass-type features. We discuss applications to Fermi systems, with particular application to metal to band insulator transitions, change of Fermi surface topology, divergent effective masses, Dirac systems, and topological insulators. Both regular periodic and glassy (and spatially chaotic behavior) may be found in


    Directory of Open Access Journals (Sweden)



    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

  17. Calcareous scales formed by cathodic protection—an assessment of characteristics and kinetics (United States)

    Neville, Anne; Morizot, Arnaud P.


    An electrochemical technique using the assessment of the rate of oxygen reduction at a rotating disk electrode has been used in conjunction with surface analysis by X-ray photoelectron spectroscopy to study the first layer formation of calcareous deposits under cathodic protection in various solutions. The study has shown that the electrochemical technique is an effective means of monitoring scale formation and that the existing models which predict scale formation by a basal layer of Mg(OH) 2 followed by CaCO 3 are over-simplified. The advantages of using an integrated approach of electrochemical analysis and a surface sensitive analysis technique in characterising the initial scale as a function of the solution composition are presented and discussed and revised models describing the temporal development of calcareous layers in saline solutions are suggested.

  18. Experimental study of multi-scale heat transfer characteristics at pool boiling (United States)

    Serdyukov, V.; Surtaev, A.


    This study presents the results of the experimental investigation of local and integral characteristics of heat transfer at liquid pool boiling. Saturated ethanol and water were used as the working fluids. Thin, resistively heated indium-tin oxide films deposited onto the sapphire substrates were used as the heaters. The synchronized measurements of the heater surface temperature field and dynamics of vapor bubbles were performed by high-speed infrared thermography with the frame rate of 1000 fps and resolution of up to 0.13 μm/px and high-speed video recording. In this paper new data on major local boiling characteristics, such as nucleation site density, dynamics of vapor bubbles, temporal characteristics and nucleation frequency at different heat fluxes and superheating and their comparison with correlations are presented.

  19. Relationship between bird abundances and landscape characteristics: the influence of scale. (United States)

    Brennan, Sarah P; Schnell, Gary D


    Scale is important to consider when investigating effects of the environment on a species. Breeding Bird Survey (BBS) data and landscape metrics derived from aerial photographs were evaluated to determine how relationships of bird abundances with landscape variables changed over a continuous range of 16 spatial scales. We analyzed the average number of birds per stop (1985-1994) for five songbird species (family Cardinalidae) for each of 50 stops on 198 BBS transects throughout six states in the Central Plains, USA. Land along each transect was categorized into six cover types, and landscape metrics of fractal dimension (a measure of shape complexity of habitat patches), edge density, patch density, and percent area were calculated, with principal components used to construct composite environmental variables. Associations of bird abundances and landscape variables changed in accordance with small scale changes. Abundances of three species were correlated with edge density and one with component I, which subsumes initial variables of patch density for urban, closed forest, open forest, and open country. Fractal dimension and component II (summarizing amount of closed forest versus open country) were associated with the most species. Correlation patterns of fractal dimension with northern cardinal (Cardinalis cardinalis) and painted bunting (Passerina ciris) abundances were similar, with highest correlations at intermediate to small scales, suggesting indirectly that these species thrive in areas where local habitat conditions are most important. Multiscale analysis can provide insight into the spatial scale(s) at which species respond, a topic of intrinsic scientific interest with applied implications for researchers establishing protocols to assess and monitor avian populations.

  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


    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. Psychometric Characteristics of the Social Justice Scale's Turkish Form and a Structural Equation Modeling (United States)

    Cirik, Ilker


    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…

  2. The characteristic scale as a consistent indicator of lung nodule size in CT imaging


    Diciotti, Stefano; Lombardo, Simone; Coppini, Giuseppe; Grassi, L.; Petrolo, L; G.Picozzi; Falchini, Massimo; Mascalchi, Mario


    Nodule growth as observed in CT scans is the primary malignancy clue of indeterminate small lung nodules. A new approach to assess the 3D size of lung nodules which is based on LoG scale space theory is described. Validation using private (ITALUNG) and public (LIDC) data-set are described.

  3. Emotional Eating Scale for Children and Adolescents: Psychometric Characteristics in a Spanish Sample (United States)

    Perpina, Conxa; Cebolla, Ausias; Botella, Cristina; Lurbe, Empar; Torro, Maria-Isabel


    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…

  4. Psychometric Characteristics of the Korean Version of the Satisfaction with Life Scale Adapted for Children (United States)

    Lim, Young-Jin


    The aim of this study was to examine the internal consistency reliability, test-retest reliability, factorial structure validity, and convergent validity of a Korean version of the Satisfaction With Life Scale adapted for children (K-SWLS-C). Participants consisted of 653 elementary school students (48% were male). The internal consistency of the…

  5. LiDAR measurements of full scale wind turbine wake characteristics

    DEFF Research Database (Denmark)

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


    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...

  6. 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


    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.

  7. Three-Dimensional Simulation of SOFC Anode Polarization Characteristics Based on Sub-Grid Scale Model



    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...

  8. Negative-resistance voltage-current characteristics of superconductor contact junctions for macro-scale applications

    CERN Document Server

    Takayasu, M; Minervini, J V; 10.1109/TASC.2003.812854


    Voltage-current characteristics of mechanical pressure contact junctions between superconducting wires are investigated using a voltage-driving method. It is found that the switching regions at low voltages result from negative resistance of the contact junction. The current transport of the contact junctions is discussed from the perspective of two existing models: the multiple Andreev reflections at the two SN interfaces of a SNS (Superconductor/Normal metal /Superconductor) junction and the inhomogeneous multiple Josephson weak-link array. (13 refs).

  9. Diet Activity Characteristic of Large-scale Sports Events Based on HACCP Management Model

    Directory of Open Access Journals (Sweden)

    Xiao-Feng Su


    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.

  10. Estimation of genome length

    Institute of Scientific and Technical Information of China (English)


    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.

  11. 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.


    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.

  12. Characteristics of Small-scale Gravity Wave Propagation in the Mesopause Region over Alaska (United States)

    Kubota, M.; Yamaguchi, Y.; Kawamura, S.; Murayama, Y.; Kita, K.


    We investigated characteristics of the atmospheric gravity waves (AGWs) propagation using sodium airglow images obtained by an all-sky imager installed at Poker Flat Research Range (65.1N, 147.4W, MLAT 65.6) in Alaska. In this study, we developed data analysis programs which automatically derive the unambiguous 2-D power spectrum from the sodium airglow images, using a method by Coble et al. (1998). The power spectrums of the AGWs which have horizontal wavelengths between 2 - 400 km and periods up to 8 hours were obtained by these programs. Statistical study of the AGW data and mesospheric wind data by an MF radar during two winter seasons from October 2000 to April 2002 indicates the following characteristics. - During these periods, the AGW dominantly propagated westward in the zonal direction. - The meridional propagation direction frequently changed. This change seems to be explained by filtering effect by the mesospheric wind. - Total power of the AGW increased in December and January. In this paper, we discuss the relationship between these characteristics of the AGW propagation and unique phenomena in high-latitude region such as auroral precipitation. Acknowledgements This work is conducted as a part of "Alaska Project", the cooperative research project between NICT and Geophysical Institute of University of Alaska. Reference Coble, M. R., G. C. Papen, and C. S. Gardner, Computing two-dimensional unambiguous horizontal wavenumber spectra from OH airglow images, IEEE Trans. Geosci. and Remote Sens., 36, 368--382, 1998.

  13. Communication Characteristics of Large-Scale Scientific Applications for Contemporary Cluster Architectures

    Energy Technology Data Exchange (ETDEWEB)

    Vetter, J S; Mueller, F


    This paper examines the explicit communication characteristics of several sophisticated scientific applications; which, by themselves, constitute a representative suite of publicly available benchmarks for large cluster architectures. By focusing on the Message Passing Interface (MPI) and by using hardware counters on the microprocessor, we observe each application's inherent behavioral characteristics: point-to-point and collective communication, and floating-point operations. Furthermore, we explore the sensitivities of these characteristics to both problem size and number of processors. Our analysis reveals several striking similarities across, our diverse set of applications including the use of collective operations, especially those collectives with very small data payloads. We also highlight a trend of novel applications parting with regimented, static communication patterns in favor of dynamically evolving patterns, as evidenced by our experiments on applications that use implicit linear solvers and adaptive mesh refinement. Overall, our study contributes a better understanding of the requirements of current and emerging paradigms of scientific computing in terms of their computation and communication demands.

  14. Mouth- harp Scale and Its Characteristics%口弦音阶及其律学特性

    Institute of Scientific and Technical Information of China (English)



    本文以口弦的音阶为题材,介绍了口弦的发音原理,例举了不同民族口弦音乐所用的不同音阶,阐释了口弦音阶构成的自然规则,总结了口弦音阶赖以生成的谐音系列的邻音程关系,口弦基音与旋律的调式、调性关系,以及谐音系列的六个重要特性:非演绎性、隐含性、精确性、不可变性、选择性和拟它性。%This paper studies the scale of mouth harp, introduces articulation principium of the instru- ment, exemplifies different scales used by distinctive nationalities and interprets natural rules of the scale formation. The study further summarizes the relationship of adjacent intervals in harmonic tones depend on which the mouth - harp scale is formulated, the relationship between the fundamental tone, music modes and tones, as well as the six important characteristics of harmonic tones.

  15. Telomere Length and Mortality

    DEFF Research Database (Denmark)

    Kimura, Masayuki; Hjelmborg, Jacob V B; Gardner, Jeffrey P


    Leukocyte telomere length, representing the mean length of all telomeres in leukocytes, is ostensibly a bioindicator of human aging. The authors hypothesized that shorter telomeres might forecast imminent mortality in elderly people better than leukocyte telomere length. They performed mortality...

  16. QuantitatiVe Characteristics of Xylem Cells and Variation in Vessel Element Length and Fibre Length for 13 Psammophytes%13种沙生植物纤维和导管分子长度变异的研究及木质部特征的定量研究

    Institute of Scientific and Technical Information of China (English)

    杨淑敏; 江泽慧; 任海青; 古川郁夫


    对13种沙生植物的纤维长和导管分子长度进行了测定分析,二者的径向变异规律呈现上升,下降,波动或恒定不变趋势.所选树种的平均纤维长度小于900μm,属于较短纤维.所选树种的纤维长度和导管分子长度除沙冬青年轮内差异不显著外,其他树种间及树种年轮间的差异极其显著.对沙生植物的解剖特征的定量研究可以看出,所选树种的次生木质部特征体现了对沙漠环境的高度适应性.较短,孔径较窄导管以单管孔或复管孔形态出现,纹孔较小使干旱区沙生植物具有较大的水分运输能力,也是水分安全传导的一种策略.%Fibre length and vessel element length were measured and analyzed in 13 psammophytes grown in arid sandy region,and the horizontal variations of them showed decreasing,increasing,considerable fluctuations or constant tendency with age.Fibre length is less than 900 μm which included in short range according to IAWA Committee.There was significant difference in both fibre length and vessel element length among-tree and within-tree except A.mongolicus.From the quantitative study of anatomical characteristics,the secondary xylem cells have high adaptability to desert.Vessels solitary or grouped in multiples with small diameter,very short elements and minute pits ale in respond to demands for greater water transport capacity and the above appearances in the xylem of arid zone species are interpreted as a strategy for conductive safety.

  17. Multi—scale Analysis of Chaotic Characteristics in a Gas—Solid Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    ZHENLing; CHENBochuan; 等


    Deterministic chaos theory offers useful quantitative tools to characterize the non-linear dynamic behavior of a fluidized bed and the developed complexity theory presents a new approach to evaluate finite sequences. In this paper,the non-linear,hydrodynamic behavior of the pressure flutuation signals in a reactor was discussed by chaos parameters and complexity measures.Coherent results were achieved by our multi-scale analysis,which further exposed the behavior in a gas-solid two-phase system.

  18. Twin Reversed Arterial Perfusion (TRAP Sequence; Characteristic Gray-Scale and Doppler Ultrasonography Findings

    Directory of Open Access Journals (Sweden)



    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. Twin Reversed Arterial Perfusion (TRAP) Sequence; Characteristic Gray-Scale and Doppler Ultrasonography Findings. (United States)

    Buyukkaya, Ayla; Tekbas, Guven; Buyukkaya, Ramazan


    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.

  20. 5种松毛虫翅面鳞片超微结构观察与比较%Comparison among the ultrastructures and characteristics of wing scales in 5 species of pine caterpillar moths

    Institute of Scientific and Technical Information of China (English)

    谭琼; 温俊宝; 李镇宇


    part of the length and the mix-ridge-number of scales among species was striking.The characteristics of scales were analyzed by hierarchical cluster.The consequences show that the similarity of wing scales among different geographic populations of the same moth is higher,i.e.different geographic populations of the same species are usually clustered together.Although the ultrastructure and characteristics of wing scales could provide some evidence for the study of phylogeny,they should not be used alone for species identification.

  1. 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


    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.

  2. Information, polarization and term length in democracy

    DEFF Research Database (Denmark)

    Schultz, Christian


    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....

  3. The electrical conductivity characteristics of Fe/Cu nano-scale multilayer materials

    Institute of Scientific and Technical Information of China (English)


    A mathematical model for describing the relationship betweenelectrical conductivity and the thickness of bilayer, ratio of sublayer thickness of a nano-scale multilayer material (MLM) is presented. Fe/Cu MLM was synthesized by electron beam physical vapor deposition (EB-PVD) technique, and the dependence of electrical conductivity of Fe/Cu MLM on the bilayer thickness and ratio of sublayer thickness were investigated. It is shown that the electrical conductivity of Fe/Cu MLM with fixed ratio of sublayer thickness decreases sharply when the thickness of bilayer becomes thinner than 30 nm. When the bilayer thickness is kept constant, the electrical conductivity linearly decreases with the increasing ratio of sublayer thickness. The values of parameters in the model were obtained by fitting the measured results of electrical conductivity of Fe/Cu MLM with fixed ratio of sublayer thickness. It is found that the calculated values agree well with measured ones.

  4. Time-scale characteristics of Kasai river hydrological regime variability for 1940-1999

    CERN Document Server

    Mbuebue, Jean-Marie Tshitenge; Mwamba, Vincent Lukanda; Phuati, Edmond Phuku; Bantu, Albert Kazadi Mukenga; Keto, Franck Tondozi


    The present study was undertaken with the aim of contributing to the characterization of the nonstationary variability of the hydrological regime of the Kasai River using the wavelet analysis for 1940-1999. The rainfalls and discharge over Kasai Basin have marked fluctuations with a perceptible downward trend and some shift around 1950, 1960, 1970, 1983 and 1994. The results show that rainfalls over Kasai basin and the discharge at Ilebo station patterns exhibit a strong annual oscillation and some intermittent oscillations in 2-8 years (1950-1975, 1983-1995) and 8-16 years (1970-1999) time scales. The wavelet coherence analysis reveals a weak possible connection between hydrological variables (rainfalls, discharge) and climate indices relative to sea surface temperature and atmospheric circulation over Atlantic tropical, Indian and Pacific Oceans (coherence less than 0.55).

  5. Spectral Characteristics of Large-Scale Radio Emission Areas in Coronal Holes

    CERN Document Server

    Prosovetsky, D V; Kochanov, A A


    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.

  6. Torque Characteristics Simulation on Small Scale Combined Type Vertical Axis Wind Turbine (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.

  7. Combustion Characteristics of Lignite Char in a Laboratory-scale Pressurized Fluidized Bed Combustor (United States)

    Murakami, Takahiro; Suzuki, Yoshizo

    In a dual fluidized bed gasifier, the residual char after steam gasification is burnt in riser. The objectives of this work are to clarify the effect of parameters (temperature, pressure, and particle size of lignite char) of char combustion using a laboratory-scale pressurized fluidized bed combustor (PFBC). As a result, the burnout time of lignite char can be improved with increasing operating pressure, and temperature. In addition, the decrease in the particle size of char enhanced the effect on burnout time. The initial combustion rate of the char can be increased with increasing operating pressure. The effect was decreased with increasing operating temperature. However, the effect of operating pressure was slightly changed in small particle size, such as 0.5-1.0 mm. It takes about 20 sec to burn 50% of char in the operating pressure of 0.5 MPa and the particle size of 0.5-1.0 mm.

  8. Characteristics of Nitrogen Balances of Large-scale Stock Farms and Reduction of Environmental Nitrogen Loads (United States)

    Hattori, Toshihiro; Takamatsu, Rieko

    We calculated nitrogen balances on farm gate and soil surface on large-scale stock farms and discussed methods for reducing environmental nitrogen loads. Four different types of public stock farms (organic beef, calf supply and daily cows) were surveyed in Aomori Prefecture. (1) Farm gate and soil surface nitrogen inflows were both larger than the respective outflows on all types of farms. Farm gate nitrogen balance for beef farms were worse than that for dairy farms. (2) Soil surface nitrogen outflows and soil nitrogen retention were in proportion to soil surface nitrogen inflows. (3) Reductions in soil surface nitrogen retention were influenced by soil surface nitrogen inflows. (4) In order to reduce farm gate nitrogen retention, inflows of formula feed and chemical fertilizer need to be reduced. (5) In order to reduce soil surface nitrogen retention, inflows of fertilizer need to be reduced and nitrogen balance needs to be controlled.

  9. Assessing the influence of watershed characteristics on chlorophyll a in waterbodies at global and regional scales (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.


    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.

  10. Nanometer-Scale Pore Characteristics of Lacustrine Shale, Songliao Basin, NE China.

    Directory of Open Access Journals (Sweden)

    Min Wang

    Full Text Available In shale, liquid hydrocarbons are accumulated mainly in nanometer-scale pores or fractures, so the pore types and PSDs (pore size distributions play a major role in the shale oil occurrence (free or absorbed state, amount of oil, and flow features. The pore types and PSDs of marine shale have been well studied; however, research on lacustrine shale is rare, especially for shale in the oil generation window, although lacustrine shale is deposited widely around the world. To investigate the relationship between nanometer-scale pores and oil occurrence in the lacustrine shale, 10 lacustrine shale core samples from Songliao Basin, NE China were analyzed. Analyses of these samples included geochemical measurements, SEM (scanning electron microscope observations, low pressure CO2 and N2 adsorption, and high-pressure mercury injection experiments. Analysis results indicate that: (1 Pore types in the lacustrine shale include inter-matrix pores, intergranular pores, organic matter pores, and dissolution pores, and these pores are dominated by mesopores and micropores; (2 There is no apparent correlation between pore volumes and clay content, however, a weak negative correlation is present between total pore volume and carbonate content; (3 Pores in lacustrine shale are well developed when the organic matter maturity (Ro is >1.0% and the pore volume is positively correlated with the TOC (total organic carbon content. The statistical results suggest that oil in lacustrine shale mainly occurs in pores with diameters larger than 40 nm. However, more research is needed to determine whether this minimum pore diameter for oil occurrence in lacustrine shale is widely applicable.

  11. 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


    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.

  12. Cyclic Codes of Length 2

    Indian Academy of Sciences (India)

    Manju Pruthi


    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.

  13. 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

    Energy Technology Data Exchange (ETDEWEB)

    Bovy, Jo [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States); Rix, Hans-Walter, E-mail: [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany)


    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 kpc < R{sub GC} < 12 kpc and 0.3 kpc ≲ |Z| ≲ 3 kpc. 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 5% over 4.5 kpc < R{sub GC} < 9 kpc. Using metal-poor MAPs with small radial scale lengths as dynamical tracers probes 4.5 kpc ≲ R{sub GC} ≲ 7 kpc, while MAPs with longer radial scale lengths sample 7 kpc ≲ R{sub GC} ≲ 9 kpc. We measure the mass-weighted Galactic disk scale length to be R{sub d} = 2.15 ± 0.14 kpc, in agreement with the photometrically inferred spatial distribution of stellar mass. We thereby measure dynamically the mass of the Galactic stellar disk to unprecedented accuracy: M {sub *} = 4.6 ± 0.3 + 3.0 (R {sub 0}/ kpc – 8) × 10{sup 10} M {sub ☉} and a total local surface density of Σ{sub R{sub 0}}(Z=1.1 kpc)=68 ± 4 M{sub ⊙} pc{sup −2} of which 38 ± 4 M {sub ☉} pc{sup –2} is contributed by stars and stellar remnants. By combining our surface density measurements with the terminal velocity curve, we find that the MW's disk is maximal in the sense that V {sub c,} {sub disk}/V {sub c,} {sub total} = 0.83 ± 0.04 at R = 2.2 R{sub d} . We also constrain for the first time the radial profile of the dark halo at such small Galactocentric radii, finding that ρ{sub DM}(r; ≈R {sub 0})∝1/r {sup α} with α < 1.53 at 95% confidence. Our results show that action-based DF modeling of complex stellar data sets is now a feasible

  14. On-farm characteristics and biosecurity protocols for small-scale swine producers in eastern Australia. (United States)

    Schembri, N; Hernandez-Jover, M; Toribio, J-A L M L; Holyoake, P K


    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 (biosecurity practices. Producers who kept pigs for primary income were more likely to provide 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

  15. Pharmacologically induced erect penile length and stretched penile length are both good predictors of post-inflatable prosthesis penile length. (United States)

    Osterberg, E C; Maganty, A; Ramasamy, R; Eid, J F


    Inflatable penile prosthesis (IPP) remains the gold standard for the surgical treatment of refractory erectile dysfunction; however, current literature to aid surgeons on how best to counsel patients on their postoperative inflated penile length is lacking. The aim of this study was to identify preoperative parameters that could better predict postoperative penile length following insertion of an IPP. Twenty men were enrolled in a prospective study examining penile lengths before and after IPP surgery. Patients with Peyronie's disease were excluded from this analysis. Baseline preoperative characteristics, including body mass index, history of hypertension, diabetes, Sexual Health Inventory for Men scores and/or prior radical prostatectomy were recorded. All patients underwent implantation with a three-piece inflatable Coloplast penile prosthesis. We compared stretched penile length to pharmacologically induced erect lengths. Postoperatively, we measured inflated penile lengths at 6 weeks and assessed patients' perception of penile size at 12 weeks. The median (±interquartile range) stretched penile length and pharmacologically induced erect penile length was 15 (±3) and 14.25 (±2) cm, respectively (P=0.5). Median post-prosthesis penile length (13.5±2.13 cm) was smaller than preoperative pharmacologically induced length (P=0.02) and preoperative stretched penile length (P=0.01). The majority of patients (70%) had a decrease in penile length (median loss 0.5±1.5 cm); however, this loss was perceptible by 43% of men. Stretched penile length and pharmacologically induced erect penile length were equally good predictors of postoperative inflated length (Spearman's correlation 0.8 and 0.9, respectively). Pharmacologically induced erect penile length and stretched penile lengths are equal predictors of post-prosthesis penile length. The majority of men will experience some decrease in penile length following prosthesis implantation; however <50% report a

  16. Examination of the metric characteristics of a Switzerland Competence Assessment Scale as an indicator of school readiness of preschool children

    Directory of Open Access Journals (Sweden)

    Joško Sindik


    Full Text Available Competence is “ability at work”, ability that is recognized in a certain activity, while the formation of a competent individual begins as early as preschool. The main objective of this research was to determine the psychometric properties of the Competence Assessment Scale, based on practical experience in the Swiss canton of Glarus, and to describe readiness of children to attend school. The sample of children that involved four kindergartens in Zagreb, Split and Ivanić Grad was examined, with a mean age of 6.26±0.42 years, of which there was 112 girls and 146 boys. Behavioral characteristics of children using the Competence Assessment Scale have been evaluated by 60 children educators from 30 school groups of all kindergartens. There was a positive, although low to medium-high correlation between the estimated level of children's competencies. All items of all SPK subscales were satisfactorily saturated corresponding to principal components. However, SPK shows somewhat lower discriminability. Preliminary testing showed that SPK, applied to a sample of preschool children in Croatia provides a valid and reliable results, and as such can help in assessment of each child for school. Scale is more sensitive at lower levels of competencies, which allows for identification of children with less developed competencies, but not in assessing the most competent children.

  17. Influences of NOM composition and bacteriological characteristics on biological stability in a full-scale drinking water treatment plant. (United States)

    Park, Ji Won; Kim, Hyun-Chul; Meyer, Anne S; Kim, Sungpyo; Maeng, Sung Kyu


    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.

  18. Calculation and characteristics analysis of blade pitch loads for large scale wind turbines

    Institute of Scientific and Technical Information of China (English)


    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.

  19. Determination of summer monsoon onset and its related large-scale circulation characteristics over Pakistan (United States)

    Latif, M.; Syed, F. S.


    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.

  20. Low-temperature microwave characteristics of 0.1 micron gate-length pseudomorphic In(0.52)Al(0.48)As/In(x)Ga(1-x)As (x = 0.85 and 0.95) MODFET's (United States)

    Yang, D.; Bhattacharya, P. K.; Brock, T.; Alterovitz, S. A.; Taub, S. R.; Young, P. G.


    We have studied the microwave characteristics of 0.1 micron gate-length pseudomorphic In(0.52)Al(0.48)As/In(x)Ga(1-x)As (x = 0.85 and 0.95) modulation-doped field-effect transistors (MODFET's) at 300 K and lower temperatures down to 77 K. A maximum f(sub T) of 151 GHz has been measured for a 0.1 x 55 micron(exp 2) gate In(0.52)Al(0.48)As/In(0.85)Ga(0.15)As MODFET at 77 K and this represents an improvement of 33% over the room temperature value. This behavior has been analyzed.

  1. Multifractal Analysis of the Small Time-Scale Boundary-Layer Characteristics of the Wind: the Anisotropy and Extremes (United States)

    Fitton, G. F.; Tchiguirinskaia, I.; Schertzer, D. J.; Lovejoy, S.


    Under various physical conditions (mean temperature and velocity gradients, stratification and rotation) atmospheric turbulent flows remain intrinsically anisotropic. The immediate vicinity of physical boundaries rises to a greater complexity of the anisotropy effects. In this paper we address the issue of the scaling anisotropy of the wind velocity fields within the atmospheric boundary layer (ABL). Under the universal multifractal (UM) framework we compare the small time-scale (0.1 to 1,000 seconds) boundary-layer characteristics of the wind for two different case studies. The first case study consisted of a single mast located within a wind farm in Corsica, France. Three sonic anemometers were installed on the mast at 22, 23 and 43m, measuring three-dimensional wind velocity data at 10Hz. Wakes, complex terrain and buoyancy forces influenced the measurements. The second case study (GROWIAN experiment in Germany) consisted of an array of propeller anemometers measuring wind speed inflow data at 2.5Hz over flat terrain. The propeller anemometers were positioned vertically at 10, 50, 75, 100, 125 and 150m with four horizontal measurements taken at 75, 100 and 125m. The spatial distribution allowed us to calculate the horizontal and vertical shear structure functions of the horizontal wind. Both case studies are within a kilometre from the sea. For the first case study (10Hz measurements in a wind farm test site) the high temporal resolution of the data meant we observed Kolmogorov scaling from 0.2 seconds (with intermittency correction) right up to 1,000 seconds at which point a scaling break occurred. After the break we observed a scaling power law of approximately 2, which is in agreement with Bolgiano-Obukhov scaling theory with intermittency correction. However, for the second case study (2.5Hz on flat terrain) we only observed Kolmogorov scaling from 6.4 seconds (also with intermittency correction). The spectra of horizontal velocity components remain

  2. 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 (United States)

    Iwase, H.; Koizumi, S.; Iikura, H.; Matsubayashi, M.; Yamaguchi, D.; Maekawa, Y.; Hashimoto, T.


    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).

  3. Hydrological connectivity of hillslopes and streams: Characteristic time scales and nonlinearities (United States)

    McGuire, Kevin J.; McDonnell, Jeffrey J.


    Subsurface flow from hillslopes is widely recognized as an important contributor to streamflow generation; however, processes that control how and when hillslopes connect to streams remain unclear. We investigated stream and hillslope runoff dynamics through a wet-up period in watershed 10 of the H. J. Andrews Experimental Forest in the western Cascades of Oregon where the riparian zone has been removed by debris flows. We examined the controls on hillslope-stream connectivity on the basis of observations of hydrometric, stable isotope, and applied tracer responses and computed transit times for multiple runoff components for a series of storms during the wet-up phase of the 2002-2003 winter rainy season. Hillslope discharge was distinctly threshold-like with a near linear response and average quick flow ratio of 0.58 when antecedent rainfall was greater than 20 mm. Hillslope and stream stormflow varied temporally and showed strong hysteretic relationships. Event water mean transit times (8-34 h) and rapid breakthrough from applied hillslope tracer additions demonstrated that subsurface contributing areas extend far upslope during events. Despite rapid hillslope transport processes during events, soil water and runoff mean transit times during nonstorm conditions were greater than the time scale of storm events. Soil water mean transit times ranged between 10 and 25 days. Hillslope seepage and catchment base flow mean transit times were between 1 and 2 years. We describe a conceptual model that captures variable physical flow pathways, their synchronicity, threshold activation, hysteresis, and transit times through changing antecedent wetness conditions that illustrate the different stages of hillslope and stream connectivity.

  4. Effect of Concrete Cracks on Dynamic Characteristics of Powerhouse for Giant-Scale Hydrostation

    Institute of Scientific and Technical Information of China (English)

    TIAN Ziain; ZHANG Yunliang; MA Zhenvue; CHEN Jing


    With the increase of capacity and size of the hydro-generator unit, the spiral case be-comes a more super-giant hydraulic structure with very high hid value, where H and D denote water head and maximum intake diameter of spiral case, respectively. Due to the induced lower stiffness by the more giant size and adverse operation conditions, dynamic performances of the powerhouse and the supporting structure for the giant units have become more important and attracted much attention. If the manner of steel spiral case embedded directly in concrete is adopted, on some locations of the concrete surrounding the spiral case, distributed and concentrated cracks will emerge due to high tensile stress. Although the concrete is reinforced well to control the maximum crack width, definitely these cracks will reduce the local and entire stiffness of the powerhouse.Under dynamic loads such as hydraulic forces including water pressure pulsation in flow passage acting on the structure, effect of the cracks on the dynamic characteristics of the local members and entire structure needs to be evaluated. However, research on this subject is few in hydroelectric engineering. In this paper, Three-Gorge Project was taken as an example to evaluate effect of such cracks on natural frequencies and the vibration responses of the powerhouse under hydraulic and earthquake forces in detail. Results show that cracks only reduce the local structural stiffness greatly but have little effect on the entire powerhouse especially the superstructure; vibrations of powerhouse with cracks in concrete surrounding the spiral case are still under the design limits.Results in this paper have been verified by practice of Three-Gorge Project.

  5. Characteristics of meter-scale surface electrical discharge propagating along water surface at atmospheric pressure (United States)

    Hoffer, Petr; Sugiyama, Yuki; Hosseini, S. Hamid R.; Akiyama, Hidenori; Lukes, Petr; Akiyama, Masahiro


    This paper reports physical characteristics of water surface discharges. Discharges were produced by metal needle-to-water surface geometry, with the needle electrode driven by 47 kV (FWHM) positive voltage pulses of 2 µs duration. Propagation of discharges along the water surface was confined between glass plates with 2 mm separation. This allowed generation of highly reproducible 634 mm-long plasma filaments. Experiments were performed using different atmospheres: air, N2, and O2, each at atmospheric pressure. Time- and spatially-resolved spectroscopic measurements revealed that early spectra of discharges in air and nitrogen atmospheres were dominated by N2 2nd positive system. N2 radiation disappeared after approx. 150 ns, replaced by emissions from atomic hydrogen. Spectra of discharges in O2 atmosphere were dominated by emissions from atomic oxygen. Time- and spatially-resolved emission spectra were used to determine temperatures in plasma. Atomic hydrogen emissions showed excitation temperature of discharges in air to be about 2  ×  104 K. Electron number densities determined by Stark broadening of the hydrogen H β line reached a maximum value of ~1018 cm-3 just after plasma initiation. Electron number densities and temperatures depended only slightly on distance from needle electrode, indicating formation of high conductivity leader channels. Direct observation of discharges by high speed camera showed that the average leader head propagation speed was 412 km · s-1, which is substantially higher value than that observed in experiments with shorter streamers driven by lower voltages.

  6. Large-scale characteristics of interstellar dust from COBE DIRBE observations (United States)

    Sodroski, T. J.; Bennett, C.; Boggers, N.; Dwek, E.; Franz, B. A.; Hauser, M. G.; Kelsall, T.; Moseley, S. H.; Odegard, N.; Silverberg, R. F.


    Observations from the COBE Diffuse Infrared Background Experiment of the 140 and 240 micrometer emissions from the Galatic plane region (absolute value of b less than 10 deg) are combined with radio surveys that trace the molecular (H2), neutral atomic (H I), and extended low-density (n(sub e) approximately 10 to 100/cm(exp 3)) ionized (H II) gas phases of the interstellar medium to derive physical conditions such as the dust temperature, dust-to-gas mass ratio, and far-infrared emissivity (1) averaged over these gas phases along each line of sight and (2) within each of these three gas phases. This analysis shows large-scale longitudinal and latitudinal gradients in the dust temperature and a decrease in dust temperature with increasing Galactocentric distance. The derived dust temperatures are significantly different from those derived in similar analyses using the Infrared Astronomical Satellite (IRAS) 60 and 100 micrometer data, suggesting that small (5 A approximately less than radius approximately less than 200 A) transiently heated dust particles contribute significantly o the Galactic 60 micrometer emission. It is found that 60% to 75% of the far-infrared luminosity arises from cold (approximately 17 to 22 K) dust associated with diffuse H I clouds, 15% to 30% from cold (approximately 19 K) dust associated with molecular gas, and less than 10% from warm (approximately 29 K) dust in extended low-density H II regions, consistent with the results of the IRAS analyses of the Galactic 60 and 100 micrometer emission. Within 2 deg of longitude of the Galactic center, the derived gas-to-dust mass ratio along the line of sight, G(sub d), reverses its general trend of decreasing G(sub d) toward the inner Galaxy and increases by a factor of approximately 2 to 3 toward the Galactic center. One possible explanation for this result is that the ratio of H2 column density to (12)CO intensity is lower in the Galactic center region than in the Galactic disk.

  7. Chromosome length scaling in haploid, asexual reproduction (United States)

    de Oliveira, P. M. C.


    We study the genetic behaviour of a population formed by haploid individuals which reproduce asexually. The genetic information for each individual is stored along a bit-string (or chromosome) with L bits, where 0-bits represent the wild allele and 1-bits correspond to harmful mutations. Each newborn inherits this chromosome from its parent with a few random mutations: on average a fixed number m of bits are flipped. Selection is implemented according to the number N of 1-bits counted along the individual's chromosome: the smaller N the higher the probability an individual has to survive a new time step. Such a population evolves, with births and deaths, and its genetic distribution becomes stabilized after sufficiently many generations have passed. The question we pose concerns the procedure of increasing L. The aim is to get the same distribution of genetic loads N/L among the equilibrated population, in spite of a larger L. Should we keep the same mutation rate m/L for different values of L? The answer is yes, which intuitively seems to be plausible. However, this conclusion is not trivial, according to our simulation results: the question also involves the population size.

  8. Chromosome length scaling in haploid, asexual reproduction

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, P M C de [Instituto de Fisica, Universidade Federal Fluminense, avenida Litoranea s/n, Boa Viagem, Niteroi 24210-340 (Brazil)


    We study the genetic behaviour of a population formed by haploid individuals which reproduce asexually. The genetic information for each individual is stored along a bit-string (or chromosome) with L bits, where 0-bits represent the wild allele and 1-bits correspond to harmful mutations. Each newborn inherits this chromosome from its parent with a few random mutations: on average a fixed number m of bits are flipped. Selection is implemented according to the number N of 1-bits counted along the individual's chromosome: the smaller N the higher the probability an individual has to survive a new time step. Such a population evolves, with births and deaths, and its genetic distribution becomes stabilized after sufficiently many generations have passed. The question we pose concerns the procedure of increasing L. The aim is to get the same distribution of genetic loads N/L among the equilibrated population, in spite of a larger L. Should we keep the same mutation rate m/L for different values of L? The answer is yes, which intuitively seems to be plausible. However, this conclusion is not trivial, according to our simulation results: the question also involves the population size.

  9. Imaging mass spectrometry at cellular length scales. (United States)

    Altelaar, A F Maarten; Luxembourg, Stefan L; McDonnell, Liam A; Piersma, Sander R; Heeren, Ron M A


    Imaging mass spectrometry (IMS) allows the direct investigation of both the identity and the spatial distribution of the molecular content directly in tissue sections, single cells and many other biological surfaces. In this protocol, we present the steps required to retrieve the molecular information from tissue sections using matrix-enhanced (ME) and metal-assisted (MetA) secondary ion mass spectrometry (SIMS) as well as matrix-assisted laser desorption/ionization (MALDI) IMS. These techniques require specific sample preparation steps directed at optimal signal intensity with minimal redistribution or modification of the sample analytes. After careful sample preparation, different IMS methods offer a unique discovery tool in, for example, the investigation of (i) drug transport and uptake, (ii) biological processing steps and (iii) biomarker distributions. To extract the relevant information from the huge datasets produced by IMS, new bioinformatics approaches have been developed. The duration of the protocol is highly dependent on sample size and technique used, but on average takes approximately 5 h.

  10. Shale gas characteristics of the Lower Toarcian Posidonia Shale in Germany: from basin to nanometre scale (United States)

    Schulz, Hans-Martin; Bernard, Sylvain; Horsfield, Brian; Krüger, Martin; Littke, Ralf; di primio, Rolando


    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

  11. 纳米级尺寸参数对钛氧化物忆阻器的特性影响∗%Influence of length parameter on the characteristics of nanoscale titanium oxide memristor

    Institute of Scientific and Technical Information of China (English)

    郭羽泉; 段书凯; 王丽丹


    According to the completeness theory of circuit, Chua [Chua L O 1971 IEEE Trans. Circ. Theor. 1971 18 507] put forward the fourth basic circuit element memristor besides resistor, inductor and capacitor in 1971. And memorisistance is defined as the ratio of the flux to the charge passing through it. With the emergence and development of nanoscale semiconductor technology, HP laboratoty successfully fabricated a physical memristor in 2008. The successful fabrication of memristive device caused a stir in the whole electronic field and thus a vast number of researchers were involved in the research, owing to its superior properties, i.e., nanoscale dimension, continuous input and output property, switching characteristics and unique non-volatile memory capacity. With all these extraordinary properties, memristors possess many possibilities for the development of future integrated circuits and 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

  12. Effects of direct-current electric fields on flame shape and combustion characteristics of ethanol in small scale

    Directory of Open Access Journals (Sweden)

    Yunhua Gan


    Full Text Available The aim of this work is to investigate the effects of direct-current electric fields on the behavior of the small-scale diffusion ethanol flame. The flow rate of liquid ethanol, the flame temperatures, and the flame shapes were measured. The results showed that the stable working ranges of a small-scale combustor became narrower under the direct-current electric field. The main reason was that the evaporation velocity of liquid ethanol limited by great heat loss effect cannot keep up with the increasing of combustion velocity by the ionic wind effect. The movements of those charged particles in flame enhanced the combustion process, resulting in higher flame temperatures under positive or negative direct-current electric field. The flame heights decreased with increasing applied voltages, due to the ionic wind effect increasing the flame temperature and the diffusivity. The flame voltage–current characteristic was also examined. Three regions can be divided: the subsaturation region, the saturation region, and the supersaturation region. Finally, the ratios of electric active power to actual burning thermal power of ethanol flame were calculated. It can be inferred that using the external direct-current electric field with little power consumption to control combustion and flame is a feasible method.

  13. Spreading lengths of Hermite polynomials

    CERN Document Server

    Sánchez-Moreno, P; Manzano, D; Yáñez, R; 10.1016/


    The Renyi, Shannon and Fisher spreading lengths of the classical or hypergeometric orthogonal polynomials, which are quantifiers of their distribution all over the orthogonality interval, are defined and investigated. These information-theoretic measures of the associated Rakhmanov probability density, which are direct measures of the polynomial spreading in the sense of having the same units as the variable, share interesting properties: invariance under translations and reflections, linear scaling and vanishing in the limit that the variable tends towards a given definite value. The expressions of the Renyi and Fisher lengths for the Hermite polynomials are computed in terms of the polynomial degree. The combinatorial multivariable Bell polynomials, which are shown to characterize the finite power of an arbitrary polynomial, play a relevant role for the computation of these information-theoretic lengths. Indeed these polynomials allow us to design an error-free computing approach for the entropic moments (w...

  14. Measuring Thermodynamic Length

    Energy Technology Data Exchange (ETDEWEB)

    Crooks, Gavin E


    Thermodynamic length is a metric distance between equilibrium thermodynamic states. Among other interesting properties, this metric asymptotically bounds the dissipation induced by a finite time transformation of a thermodynamic system. It is also connected to the Jensen-Shannon divergence, Fisher information, and Rao's entropy differential metric. Therefore, thermodynamic length is of central interestin understanding matter out of equilibrium. In this Letter, we will consider how to denethermodynamic length for a small system described by equilibrium statistical mechanics and how to measure thermodynamic length within a computer simulation. Surprisingly, Bennett's classic acceptance ratio method for measuring free energy differences also measures thermodynamic length.

  15. Realtime Prediction in Disturbed Landscapes: Identifying Highest Priority Disturbance Characteristics Impacting Streamflow Response in a CONUS-Scale Operational Model (United States)

    Dugger, A. L.; Gochis, D. J.; Yu, W.; McCreight, J. L.; Barlage, M. J.


    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

  16. Deriving the Characteristic Scale for Effectively Monitoring Heavy Metal Stress in Rice by Assimilation of GF-1 Data with the WOFOST Model. (United States)

    Huang, Zhi; Liu, Xiangnan; Jin, Ming; Ding, Chao; Jiang, Jiale; Wu, Ling


    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.

  17. 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


    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.

  18. Rain Characteristics and Large-Scale Environments of Precipitation Objects with Extreme Rain Volumes from TRMM Observations (United States)

    Zhou, Yaping; Lau, William K M.; Liu, Chuntao


    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.

  19. Meat Quality Characteristics of Small East African Goats and Norwegian Crosses Finished under Small Scale Farming Conditions. (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


    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 (pdiet. Increasing level of concentrate on offer increased meat 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 (pgoats 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.

  20. Factor structure of the Athens Insomnia Scale and its associations with demographic characteristics and depression in adolescents. (United States)

    Yen, Cheng-Fang; King, Bryan H; Chang, Yu-Ping


    The eight-item Athens Insomnia Scale (AIS-8) is an instrument that has been used frequently to assess insomnia problems. Previous research on adults has found that the AIS-8 functioned as a sole component. This study aimed to examine the prevalence rates of insomnia problems on the AIS-8, the factor structure of the AIS-8 in adolescents and its associations with demographic characteristics and depression in adolescents. A total of 8319 adolescent students (4334 girls and 3985 boys, mean age = 14.7 years, standard deviation = 1.7 years) in southern Taiwan were recruited into this study and completed the AIS-8. We performed an exploratory factor analysis to examine the factor structure of the AIS-8, and used the parallel analysis for making decisions regarding factor retention. We also used multiple regression analysis models to determine the associations between insomnia and demographic characteristics and depression. The results found that a high proportion of adolescents had insomnia problems as measured by the AIS-8. The AIS-8 was composed of two different factors when used among a large adolescent population, including insomnia symptoms (factor 1) and subjective sleep and daytime distress (factor 2). While being male, being younger, and having depression were associated positively with the severity of insomnia symptoms (factor 1), being older, living in urban areas, and having depression were associated positively with the severity of subjective sleep and daytime distress (factor 2). Clinicians and researchers should consider the different meanings of the two factors of the AIS-8 when using this tool to assess insomnia problems in adolescents.

  1. 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)


    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

  2. Variation Characteristics of the Large-scale Frost in East Region of the Yellow River of Gansu in Recent 40 Years

    Institute of Scientific and Technical Information of China (English)


    [Objective]The research aimed to study variation characteristics of large-scale frost in the east region of the Yellow River of Gansu in recent 40 years.[Method]Based on daily minimum temperature data at 15 meteorological stations over the east region of the Yellow River of Gansu from 1969 to 2008,according to common climatic statistical index of the frost,variation characteristics of the large-scale frost and continuous frost in the east region of the Yellow River of Gansu in recent 40 years were studied.[...

  3. Multi-scale factors influencing the characteristics of avian communities in urban parks across Beijing during the breeding season (United States)

    Xie, Shilin; Lu, Fei; Cao, Lei; Zhou, Weiqi; Ouyang, Zhiyun


    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.

  4. Design and hydraulic characteristics of a field-scale bi-phasic bioretention rain garden system for storm water management. (United States)

    Yang, H; Florence, D C; McCoy, E L; Dick, W A; Grewal, P S


    A field-scale bioretention rain garden system was constructed using a novel bi-phasic (i.e. sequence of anaerobic to aerobic) concept for improving retention and removal of storm water runoff pollutants. Hydraulic tests with bromide tracer and simulated runoff pollutants (nitrate-N, phosphate-P, Cu, Pb, and Zn) were performed in the system under a simulated continuous rainfall. The objectives of the tests were (1) to determine hydraulic characteristics of the system, and (2) to evaluate the movement of runoff pollutants through the system. For the 180 mm/24 h rainfall, the bi-phasic bioretention system effectively reduced both peak flow (approximately 70%) and runoff volume (approximately 42%). The breakthrough curves (BTCs) of bromide tracer suggest that the transport pattern of the system is similar to dispersed plug flow under this large runoff event. The BTCs of bromide showed mean 10% and 90% breakthrough times of 5.7 h and 12.5 h, respectively. Under the continuous rainfall, a significantly different transport pattern was found between each runoff pollutant. Nitrate-N was easily transported through the system with potential leaching risk from the initial soil medium, whereas phosphate-P and metals were significantly retained indicating sorption-mediated transport. These findings support the importance of hydraulics, in combination with the soil medium, when creating bioretention systems for bioremediation that are effective for various rainfall sizes and intervals.

  5. Three-dimensional macro-scale assessment of regional and temporal wall shear stress characteristics on aortic valve leaflets. (United States)

    Cao, K; Bukač, M; Sucosky, P


    The aortic valve (AV) achieves unidirectional blood flow between the left ventricle and the aorta. Although hemodynamic stresses have been shown to regulate valvular biology, the native wall shear stress (WSS) experienced by AV leaflets remains largely unknown. The objective of this study was to quantify computationally the macro-scale leaflet WSS environment using fluid-structure interaction modeling. An arbitrary Lagrangian-Eulerian approach was implemented to predict valvular flow and leaflet dynamics in a three-dimensional AV geometry subjected to physiologic transvalvular pressure. Local WSS characteristics were quantified in terms of temporal shear magnitude (TSM), oscillatory shear index (OSI) and temporal shear gradient (TSG). The dominant radial WSS predicted on the leaflets exhibited high amplitude and unidirectionality on the ventricularis (TSM>7.50 dyn/cm(2), OSI 325.54 dyn/cm(2) s) but low amplitude and bidirectionality on the fibrosa (TSM 0.38, TSG 0.25). This study provides new insights into the role played by leaflet-blood flow interactions in valvular function and critical hemodynamic stress data for the assessment of the hemodynamic theory of AV disease.

  6. Characteristic Analysis of Wind Power Output and the Selection of a Time Scale%风电出力特性分析及其时间尺度的选取

    Institute of Scientific and Technical Information of China (English)

    涂娇娇; 董晓晶; 党东升; 肖白


    风电是典型的随机电源,分析风电出力特性时,采样时间直接影响分析结果的准确性;另一方面,采样时间的长短也直接影响着工程应用计算的速度。所以选取合适的时间尺度对电力系统规划等问题的研究有着深远的意义,工程上一般选取1h作为时间尺度,进行各种问题的研究。通过某地区风电场的实测数据,对这一时间尺度运用的合理性给出数据和理论上的支持,通过3个风电出力指标在不同时间尺度下得出的特性,给出所研究问题的结论。%Wind power is a typical random power. When the characteristics of wind power output are analyzed, the sampling time directly affects the accuracy of the analysis results. On the other hand, the length of the sampling time also directly affects the speed of engineering calculations. So it’s meaningful to the study of the power system planning and other issues that an appropriate time scale is selected, and the project generally chooses one hour as the time scale to study various issues. Data and theoretical support for the rationality of the use of this time scale is provided by the measured data of wind farms in a region, and through characteristics derived from three wind power output indicators at different time scales, the conclusions of the research question is given.

  7. 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 (United States)

    Cohen, Ira L.; Tsiouris, John A.; Flory, Michael J.; Kim, Soh-Yule; Freedland, Robert; Heaney, Glenn; Pettinger, Jill; Brown, W. Ted


    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…

  8. 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.


    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

  9. Cultivation of Chlorella sp. using raw dairy wastewater for nutrient removal and biodiesel production: Characteristics comparison of indoor bench-scale and outdoor pilot-scale cultures. (United States)

    Lu, Weidong; Wang, Zhongming; Wang, Xuewei; Yuan, Zhenhong


    The biomass productivity and nutrient removal capacity of simultaneous Chlorella sp. cultivation for biodiesel production and nutrient removal in raw dairy wastewater (RDW) in indoor bench-scale and outdoor pilot-scale photobioreactors were compared. Results from the current work show that maximum biomass productivity in indoor bench-scale cultures can reach 260 mg L(-1) day(-1), compared to that of 110 mg L(-1) day(-1) in outdoor pilot-scale cultures. Maximum chemical oxygen demand (COD), total nitrogen (TN), and total phosphorous (TP) removal rate obtained in indoor conditions was 88.38, 38.34, and 2.03 mg L(-1) day(-1), respectively, this compared to 41.31, 6.58, and 2.74 mg L(-1) day(-1), respectively, for outdoor conditions. Finally, dominant fatty acids determined to be C16/C18 in outdoor pilot-scale cultures indicated great potential for scale up of Chlorella sp. cultivation in RDW for high quality biodiesel production coupling with RDW treatment.

  10. [Spatial discharge characteristics and total load control of non-point source pollutants based on the catchment scale]. (United States)

    Wang, Xia-Hui; Lu, Jun; Zhang, Qing-Zhong; Wang, Bo; Yao, Rui-Hua; Zhang, Hui-Yuan; Huang, Feng


    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

  11. Minimum Length - Maximum Velocity

    CERN Document Server

    Panes, Boris


    We study a framework where the hypothesis of a minimum length in space-time is complemented with the notion of reference frame invariance. It turns out natural to interpret the action of the obtained reference frame transformations in the context of doubly special relativity. As a consequence of this formalism we find interesting connections between the minimum length properties and the modified velocity-energy relation for ultra-relativistic particles. For example we can predict the ratio between the minimum lengths in space and time using the results from OPERA about superluminal neutrinos.

  12. Telomere length and depression

    DEFF Research Database (Denmark)

    Wium-Andersen, Marie Kim; Ørsted, David Dynnes; Rode, Line


    BACKGROUND: Depression has been cross-sectionally associated with short telomeres as a measure of biological age. However, the direction and nature of the association is currently unclear. AIMS: We examined whether short telomere length is associated with depression cross-sectionally as well...... as prospectively and genetically. METHOD: Telomere length and three polymorphisms, TERT, TERC and OBFC1, were measured in 67 306 individuals aged 20-100 years from the Danish general population and associated with register-based attendance at hospital for depression and purchase of antidepressant medication....... RESULTS: Attendance at hospital for depression was associated with short telomere length cross-sectionally, but not prospectively. Further, purchase of antidepressant medication was not associated with short telomere length cross-sectionally or prospectively. Mean follow-up was 7.6 years (range 0...

  13. Myofilament length dependent activation

    Energy Technology Data Exchange (ETDEWEB)

    de Tombe, Pieter P.; Mateja, Ryan D.; Tachampa, Kittipong; Mou, Younss Ait; Farman, Gerrie P.; Irving, Thomas C. (IIT); (Loyola)


    The Frank-Starling law of the heart describes the interrelationship between end-diastolic volume and cardiac ejection volume, a regulatory system that operates on a beat-to-beat basis. The main cellular mechanism that underlies this phenomenon is an increase in the responsiveness of cardiac myofilaments to activating Ca{sup 2+} ions at a longer sarcomere length, commonly referred to as myofilament length-dependent activation. This review focuses on what molecular mechanisms may underlie myofilament length dependency. Specifically, the roles of inter-filament spacing, thick and thin filament based regulation, as well as sarcomeric regulatory proteins are discussed. Although the 'Frank-Starling law of the heart' constitutes a fundamental cardiac property that has been appreciated for well over a century, it is still not known in muscle how the contractile apparatus transduces the information concerning sarcomere length to modulate ventricular pressure development.

  14. Observations on oesophageal length. (United States)

    Kalloor, G J; Deshpande, A H; Collis, J L


    The subject of oesophageal length is discussed. The great variations in the length of the oesophagus in individual patients is noted, and the practical use of its recognition in oesophageal surgery is stressed. An apprasial of the various methods available for this measurement is made; this includes the use of external chest measurement, endoscopic measurement, and the measurement of the level of the electrical mucosal potential change. Correlative studies of these various methods are made, and these show a very high degree of significance. These studies involved simultaneous measurement of external and internal oesophageal length in 26 patients without a hiatal hernia or gastro-oesophageal length in 26 patients without a hiatal hernia or gastro-oesophageal reflux symptoms, 42 patients with sliding type hiatal hernia, and 17 patients with a peptic stricture in association with hiatal hernia. The method of measuring oesophageal length by the use of the external chest measurement, that is, the distance between the lower incisor teeth and the xiphisternum, measured with the neck fully extended and the patient lying supine, is described in detail, its practical application in oesophageal surgery is illustrated, and its validity tested by internal measurements. The findings of this study demonstrate that the external chest measurement provides a mean of assessing the true static length of the oesophagus, corrected for the size of the individual. Images PMID:941114

  15. Equilibrium CO bond lengths (United States)

    Demaison, Jean; Császár, Attila G.


    Based on a sample of 38 molecules, 47 accurate equilibrium CO bond lengths have been collected and analyzed. These ultimate experimental (reEX), semiexperimental (reSE), and Born-Oppenheimer (reBO) equilibrium structures are compared to reBO estimates from two lower-level techniques of electronic structure theory, MP2(FC)/cc-pVQZ and B3LYP/6-311+G(3df,2pd). A linear relationship is found between the best equilibrium bond lengths and their MP2 or B3LYP estimates. These (and similar) linear relationships permit to estimate the CO bond length with an accuracy of 0.002 Å within the full range of 1.10-1.43 Å, corresponding to single, double, and triple CO bonds, for a large number of molecules. The variation of the CO bond length is qualitatively explained using the Atoms in Molecules method. In particular, a nice correlation is found between the CO bond length and the bond critical point density and it appears that the CO bond is at the same time covalent and ionic. Conditions which permit the computation of an accurate ab initio Born-Oppenheimer equilibrium structure are discussed. In particular, the core-core and core-valence correlation is investigated and it is shown to roughly increase with the bond length.

  16. 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


    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.

  17. The influence of watershed characteristics on spatial patterns of trends in annual scale streamflow variability in the continental U.S. (United States)

    Rice, Joshua S.; Emanuel, Ryan E.; Vose, James M.


    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.

  18. Characteristics of oxide scale formed on Cu-bearing austenitic stainless steel during early stages of high temperature oxidation (United States)

    Swaminathan, Srinivasan; Krishna, Nanda Gopala; Kim, Dong-Ik


    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.

  19. 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;


    , 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......Precipitation simulated by regional climate models (RCMs) is generally biased with respect to observations, especially at the local scale of a few tens of kilometers. This study investigates how well two different RCMs are able to reproduce the spatial correlation patterns of observed summer...

  20. Mappability and Read Length

    Directory of Open Access Journals (Sweden)

    Wentian eLi


    Full Text Available Power-law distributions are the main functional form forthe distribution of repeat size and repeat copy number in the human genome. When the genome is broken into fragments for sequencing, the limited size offragments and reads may prevent an unique alignment of repeatsequences to the reference sequence. Repeats in the human genome canbe as long as $10^4$ bases, or $10^5-10^6$ bases when allowing for mismatches between repeat units. Sequence reads from these regions are therefore unmappable when the read length is in the range of $10^3$ bases.With the read length of exactly 1000 bases, slightly more than 1% of theassembled genome, and slightly less than 1% of the 1kbreads, are unmappable, excluding the unassembled portion of the humangenome (8% in GRCh37. The slow decay (long tail ofthe power-law function implies a diminishing return in convertingunmappable regions/reads to become mappable with the increase of theread length, with the understanding that increasing read length willalways move towards the direction of 100% mappability.