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Sample records for granular media teach

  1. Why granular media are thermal after all

    Science.gov (United States)

    Liu, Mario; Jiang, Yimin

    2017-06-01

    Two approaches exist to account for granular behavior. The thermal one considers the total entropy, which includes microscopic degrees of freedom such as phonons; the athermal one (as with the Edward entropy) takes grains as elementary. Granular solid hydrodynamics (GSH) belongs to the first, DEM, granular kinetic theory and athermal statistical mechanics (ASM) to the second. A careful discussion of their conceptual differences is given here. Three noteworthy insights or results are: (1) While DEM and granular kinetic theory are well justified to take grains as elementary, any athermal entropic consideration is bound to run into trouble. (2) Many general principles are taken as invalid in granular media. Yet within the thermal approach, energy conservation and fluctuation-dissipation theorem remain valid, granular temperatures equilibrate, and phase space is well explored in a grain at rest. Hence these are abnormalities of the athermal approximation, not of granular media as such. (3) GSH is a wide-ranged continuum mechanical description of granular dynamics.

  2. Statistical mechanics of dense granular media

    International Nuclear Information System (INIS)

    Coniglio, A; Fierro, A; Nicodemi, M; Ciamarra, M Pica; Tarzia, M

    2005-01-01

    We discuss some recent results on the statistical mechanics approach to dense granular media. In particular, by analytical mean field investigation we derive the phase diagram of monodisperse and bidisperse granular assemblies. We show that 'jamming' corresponds to a phase transition from a 'fluid' to a 'glassy' phase, observed when crystallization is avoided. The nature of such a 'glassy' phase turns out to be the same as found in mean field models for glass formers. This gives quantitative evidence for the idea of a unified description of the 'jamming' transition in granular media and thermal systems, such as glasses. We also discuss mixing/segregation transitions in binary mixtures and their connections to phase separation and 'geometric' effects

  3. Shock waves in weakly compressed granular media.

    Science.gov (United States)

    van den Wildenberg, Siet; van Loo, Rogier; van Hecke, Martin

    2013-11-22

    We experimentally probe nonlinear wave propagation in weakly compressed granular media and observe a crossover from quasilinear sound waves at low impact to shock waves at high impact. We show that this crossover impact grows with the confining pressure P0, whereas the shock wave speed is independent of P0-two hallmarks of granular shocks predicted recently. The shocks exhibit surprising power law attenuation, which we model with a logarithmic law implying that shock dissipation is weak and qualitatively different from other granular dissipation mechanisms. We show that elastic and potential energy balance in the leading part of the shocks.

  4. Seismic wave propagation in granular media

    Science.gov (United States)

    Tancredi, Gonzalo; López, Francisco; Gallot, Thomas; Ginares, Alejandro; Ortega, Henry; Sanchís, Johnny; Agriela, Adrián; Weatherley, Dion

    2016-10-01

    Asteroids and small bodies of the Solar System are thought to be agglomerates of irregular boulders, therefore cataloged as granular media. It is a consensus that many asteroids might be considered as rubble or gravel piles.Impacts on their surface could produce seismic waves which propagate in the interior of these bodies, thus causing modifications in the internal distribution of rocks and ejections of particles and dust, resulting in a cometary-type comma.We present experimental and numerical results on the study of propagation of impact-induced seismic waves in granular media, with special focus on behavior changes by increasing compression.For the experiment, we use an acrylic box filled with granular materials such as sand, gravel and glass spheres. Pressure inside the box is controlled by a movable side wall and measured with sensors. Impacts are created on the upper face of the box through a hole, ranging from free-falling spheres to gunshots. We put high-speed cameras outside the box to record the impact as well as piezoelectic sensors and accelerometers placed at several depths in the granular material to detect the seismic wave.Numerical simulations are performed with ESyS-Particle, a software that implements the Discrete Element Method. The experimental setting is reproduced in the numerical simulations using both individual spherical particles and agglomerates of spherical particles shaped as irregular boulders, according to rock models obtained with a 3D scanner. The numerical experiments also reproduces the force loading on one of the wall to vary the pressure inside the box.We are interested in the velocity, attenuation and energy transmission of the waves. These quantities are measured in the experiments and in the simulations. We study the dependance of these three parameters with characteristics like: impact speed, properties of the target material and the pressure in the media.These results are relevant to understand the outcomes of impacts in

  5. Propulsion via flexible flapping in granular media

    Science.gov (United States)

    Peng, Zhiwei; Ding, Yang; Pietrzyk, Kyle; Elfring, Gwynn; Pak, On Shun

    2017-11-01

    Biological locomotion in nature is often achieved by the interaction between a flexible body and its surrounding medium. The interaction of a flexible body with granular media is less understood compared with viscous fluids partially due to its complex rheological properties. In this work, we explore the effect of flexibility on granular propulsion by considering a simple mechanical model in which a rigid rod is connected to a torsional spring that is under a displacement actuation using a granular resistive force theory. Through a combined numerical and asymptotic investigation, we characterize the propulsive dynamics of such a flexible flapper in relation to the actuation amplitude and spring stiffness, and we compare these dynamics with those observed in a viscous fluid. In addition, we demonstrate that the maximum possible propulsive force can be obtained in the steady propulsion limit with a finite spring stiffness and large actuation amplitude. These results may apply to the development of synthetic locomotive systems that exploit flexibility to move through complex terrestrial media. Funding for Z.P. and Y.D. was partially provided by NSFC 394 Grant No. 11672029 and NSAF-NSFC Grant No. U1530401.

  6. Properties of surface waves in granular media under gravity

    International Nuclear Information System (INIS)

    Zheng He-Peng

    2014-01-01

    Acoustical waves propagating along the free surface of granular media under gravity are investigated in the framework of elasticity theory. The influence of stress on a surface wave is analyzed. The results have shown that two types of surface waves, namely sagittal and transverse modes exist depending on initial stress states, which may have some influence on the dispersion relations of surface waves, but the influence is not great. Considering that the present experimental accuracy is far from distinguishing this detail, the validity of elasticity theory on the surface waves propagating in granular media can still be maintained. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  7. Studies of elasticity, sound propagation and attenuation of acoustic modes in granular media: final report

    Energy Technology Data Exchange (ETDEWEB)

    Makse, Hernan A. [City College of New York, NY (United States). Levich Inst., Dept. of Physcis; Johnson, David L. [Schlumberger-Doll Research, Cambridge, MA (United States)

    2014-09-03

    This is the final report describing the results of DOE Grant # DE-FG02-03ER15458 with original termination date of April 31, 2013, which has been extended to April 31, 2014. The goal of this project is to develop a theoretical and experimental understanding of sound propagation, elasticity and dissipation in granular materials. The topic is relevant for the efficient production of hydrocarbon and for identifying and characterizing the underground formation for storage of either CO2 or nuclear waste material. Furthermore, understanding the basic properties of acoustic propagation in granular media is of importance not only to the energy industry, but also to the pharmaceutical, chemical and agricultural industries. We employ a set of experimental, theoretical and computational tools to develop a study of acoustics and dissipation in granular media. These include the concept effective mass of granular media, normal modes analysis, statistical mechanics frameworks and numerical simulations based on Discrete Element Methods. Effective mass measurements allow us to study the mechanisms of the elastic response and attenuation of acoustic modes in granular media. We perform experiments and simulations under varying conditions, including humidity and vacuum, and different interparticle force-laws to develop a fundamental understanding of the mechanisms of damping and acoustic propagation in granular media. A theoretical statistical approach studies the necessary phase space of configurations in pressure, volume fraction to classify granular materials.

  8. Robophysical study of jumping dynamics on granular media

    Science.gov (United States)

    Aguilar, Jeffrey; Goldman, Daniel I.

    2016-03-01

    Characterizing forces on deformable objects intruding into sand and soil requires understanding the solid- and fluid-like responses of such substrates and their effect on the state of the object. The most detailed studies of intrusion in dry granular media have revealed that interactions of fixed-shape objects during free impact (for example, cannonballs) and forced slow penetration can be described by hydrostatic- and hydrodynamic-like forces. Here we investigate a new class of granular interactions: rapid intrusions by objects that change shape (self-deform) through passive and active means. Systematic studies of a simple spring-mass robot jumping on dry granular media reveal that jumping performance is explained by an interplay of nonlinear frictional and hydrodynamic drag as well as induced added mass (unaccounted by traditional intrusion models) characterized by a rapidly solidified region of grains accelerated by the foot. A model incorporating these dynamics reveals that added mass degrades the performance of certain self-deformations owing to a shift in optimal timing during push-off. Our systematic robophysical experiment reveals both new soft-matter physics and principles for robotic self-deformation and control, which together provide principles of movement in deformable terrestrial environments.

  9. NMR studies of granular media and two-phase flow in porous media

    Science.gov (United States)

    Yang, Xiaoyu

    This dissertation describes two experimental studies of a vibrofluidized granular medium and a preliminary study of two-phase fluid flow in a porous medium using Nuclear Magnetic Resonance (NMR). The first study of granular medium is to test a scaling law of the rise in center of mass in a three-dimensional vibrofluidized granular system. Our granular system consisted of mustard seeds vibrated vertically at 40 Hz from 0g to 14g. We used Magnetic Resonance Imaging (MRI) to measure density profile in vibrated direction. We observed that the rise in center of mass scaled as nu 0alpha/Nlbeta with alpha = 1.0 +/- 0.2 and beta = 0.5 +/- 0.1, where nu 0 is the vibration velocity and Nl is the number of layers of grains in the container. A simple theory was proposed to explain the scaling exponents. In the second study we measured both density and velocity information in the same setup of the first study. Pulsed Field Gradient (PFG)-NMR combined with MRI was used to do this measurement. The granular system was fully fluidized at 14.85g 50 Hz with Nl ≤ 4. The velocity distributions at horizontal and vertical direction at different height were measured. The distributions were nearly-Gaussian far from sample bottom and non-Gaussian near sample bottom. Granular temperature profiles were calculated from the velocity distributions. The density and temperature profile were fit to a hydrodynamic theory. The theory agreed with experiments very well. A temperature inversion near top was also observed and explained by additional transport coefficient from granular hydrodynamics. The third study was the preliminary density measurement of invading phase profile in a two-phase flow in porous media. The purpose of this study was to test an invasion percolation with gradient (IPG) theory in two-phase flow of porous media. Two phases are dodecane and water doped with CuSO4. The porous medium was packed glass beads. The front tail width sigma and front width of invading phase were

  10. Aerofractures in Confined Granular Media

    Science.gov (United States)

    Eriksen, Fredrik K.; Turkaya, Semih; Toussaint, Renaud; Måløy, Knut J.; Flekkøy, Eirik G.

    2015-04-01

    We will present the optical analysis of experimental aerofractures in confined granular media. The study of this generic process may have applications in industries involving hydraulic fracturing of tight rocks, safe construction of dams, tunnels and mines, and in earth science where phenomena such as mud volcanoes and sand injectites are results of subsurface sediment displacements driven by fluid overpressure. It is also interesting to increase the understanding the flow instability itself, and how the fluid flow impacts the solid surrounding fractures and in the rest of the sample. Such processes where previously studied numerically [Niebling 2012a, Niebling 2012b] or in circular geometries. We will here explore experimentally linear geometries. We study the fracturing patterns that form when air flows into a dense, non-cohesive porous medium confined in a Hele-Shaw cell - i.e. into a packing of dry 80 micron beads placed between two glass plates separated by ~1mm. The cell is rectangular and fitted with a semi-permeable boundary to the atmosphere - blocking beads but not air - on one short edge, while the other three edges are impermeable. The porous medium is packed inside the cell between the semi-permeable boundary and an empty volume at the sealed side where the air pressure can be set and kept at a constant overpressure (1-2bar). Thus, for the air trapped inside the cell to release the overpressure it has to move through the solid. At high enough overpressures the air flow deforms the solid and increase permeability in some regions along the air-solid interface, which results in unstable flow and aerofracturing. Aerofractures are thought to be an analogue to hydrofractures, and an advantage of performing aerofracturing experiments in a Hele-Shaw cell is that the fracturing process can easily be observed in the lab. Our experiments are recorded with a high speed camera with a framerate of 1000 frames per second. In the analysis, by using various image

  11. Frustration and disorder in granular media and tectonic blocks: implications for earthquake complexity

    Directory of Open Access Journals (Sweden)

    A. Sornette

    1994-01-01

    Full Text Available We present exploratory analogies and speculations on the mechanisms underlying the organization of faulting and earthquake in the earth crust. The mechanical properties of the brittle lithosphere at scales of the order or larger than a few kilometers are proposed to be analogous to those of non-cohesive granular media, since both systems present stress amplitudes controlled by gravity, and shear band (faulting localization is determined by a type of friction Mohr-Coulomb rupture criterion. here, we explore the implications of this correspondence with respect to the origin of tectonic and earthquake complexity, on the basis of the existing experimental data on granular media available in the mechanical literature. An important observation is that motions and deformations of non-cohesive granular media are characterized by important fluctuations both in time (sudden breaks, avalanches, which are analogous to earthquakes and space (strain localizations, yield surfaces forming sometimes complex patterns. This is in apparent contradiction with the conventional wisdom in mechanics, based on the standard tendency to homogenize, which has led to dismiss fluctuations as experimental noise. On the basis of a second analogy with spinglasses and neural networks, based on the existence of block and grain packing disorder and block rotation "frustration", we suggest that these fluctuations observed both at large scales and at the block scale constitute an intrinsic signature of the mechanics of granular media. The space-time complexity observed in faulting and earthquake phenomenology is thus proposed to result form the special properties of the mechanics of granular media, dominated by the "frustration" of the kinematic deformations of its constitutive blocks.

  12. Surface instabilities in shock loaded granular media

    Science.gov (United States)

    Kandan, K.; Khaderi, S. N.; Wadley, H. N. G.; Deshpande, V. S.

    2017-12-01

    The initiation and growth of instabilities in granular materials loaded by air shock waves are investigated via shock-tube experiments and numerical calculations. Three types of granular media, dry sand, water-saturated sand and a granular solid comprising PTFE spheres were experimentally investigated by air shock loading slugs of these materials in a transparent shock tube. Under all shock pressures considered here, the free-standing dry sand slugs remained stable while the shock loaded surface of the water-saturated sand slug became unstable resulting in mixing of the shocked air and the granular material. By contrast, the PTFE slugs were stable at low pressures but displayed instabilities similar to the water-saturated sand slugs at higher shock pressures. The distal surfaces of the slugs remained stable under all conditions considered here. Eulerian fluid/solid interaction calculations, with the granular material modelled as a Drucker-Prager solid, reproduced the onset of the instabilities as seen in the experiments to a high level of accuracy. These calculations showed that the shock pressures to initiate instabilities increased with increasing material friction and decreasing yield strain. Moreover, the high Atwood number for this problem implied that fluid/solid interaction effects were small, and the initiation of the instability is adequately captured by directly applying a pressure on the slug surface. Lagrangian calculations with the directly applied pressures demonstrated that the instability was caused by spatial pressure gradients created by initial surface perturbations. Surface instabilities are also shown to exist in shock loaded rear-supported granular slugs: these experiments and calculations are used to infer the velocity that free-standing slugs need to acquire to initiate instabilities on their front surfaces. The results presented here, while in an idealised one-dimensional setting, provide physical understanding of the conditions required to

  13. Rapid penetration into granular media visualizing the fundamental physics of rapid earth penetration

    CERN Document Server

    Iskander, Magued

    2015-01-01

    Rapid Penetration into Granular Media: Visualizing the Fundamental Physics of Rapid Earth Penetration introduces readers to the variety of methods and techniques used to visualize, observe, and model the rapid penetration of natural and man-made projectiles into earth materials. It provides seasoned practitioners with a standard reference that showcases the topic's most recent developments in research and application. The text compiles the findings of new research developments on the subject, outlines the fundamental physics of rapid penetration into granular media, and assembles a com

  14. On the rheology of dilative granular media: Bridging solid- and fluid-like behavior

    Science.gov (United States)

    Andrade, José E.; Chen, Qiushi; Le, Phong H.; Avila, Carlos F.; Matthew Evans, T.

    2012-06-01

    A new rate-dependent plasticity model for dilative granular media is presented, aiming to bridge the seemingly disparate solid- and fluid-like behavioral regimes. Up to date, solid-like behavior is typically tackled with rate-independent plasticity models emanating from Mohr-Coulomb and Critical State plasticity theory. On the other hand, the fluid-like behavior of granular media is typically treated using constitutive theories amenable to viscous flow, e.g., Bingham fluid. In our proposed model, the material strength is composed of a dilation part and a rate-dependent residual strength. The dilatancy strength plays a key role during solid-like behavior but vanishes in the fluid-like regime. The residual strength, which in a classical plasticity model is considered constant and rate-independent, is postulated to evolve with strain rate. The main appeal of the model is its simplicity and its ability to reconcile the classic plasticity and rheology camps. The applicability and capability of the model are demonstrated by numerical simulation of granular flow problems, as well as a classical shear banding problem, where the performance of the continuum model is compared to discrete particle simulations and physical experiment. These results shed much-needed light onto the mechanics and physics of granular media at various shear rates.

  15. Pneumatic fractures in Confined Granular Media

    Science.gov (United States)

    Eriksen, Fredrik K.; Toussaint, Renaud; Jørgen Måløy, Knut; Grude Flekkøy, Eirik; Turkaya, Semih

    2016-04-01

    We will present our ongoing study of the patterns formed when air flows into a dry, non-cohesive porous medium confined in a horizontal Hele-Shaw cell. This is an optically transparent system consisting of two glass plates separated by 0.5 to 1 mm, containing a packing of dry 80 micron beads in between. The cell is rectangular and has an air-permeable boundary (blocking beads) at one short edge, while the other three edges are completely sealed. The granular medium is loosely packed against the semi-permeable boundary and fills about 80 % of the cell volume. This leaves an empty region at the sealed side, where an inlet allows us to set and maintain the air at a constant overpressure (0.1 - 2 bar). For the air trapped inside the cell to relax its overpressure it has to move through the deformable granular medium. Depending on the applied overpressure and initial density of the medium, we observe a range of different behaviors such as seepage through the pore-network with or without an initial compaction of the solid, formation of low density bubbles with rearrangement of particles, granular fingering/fracturing, and erosion inside formed channels/fractures. The experiments are recorded with a high-speed camera at a framerate of 1000 images/s and a resolution of 1024x1024 pixels. We use various image processing techniques to characterize the evolution of the air invasion patterns and the deformations in the surrounding material. The experiments are similar to deformation processes in porous media which are driven by pore fluid overpressure, such as mud volcanoes and hydraulic or pneumatic (gas-induced) fracturing, and the motivation is to increase the understanding of such processes by optical observations. In addition, this setup is an experimental version of the numerical models analyzed by Niebling et al. [1,2], and is useful for comparison with their results. In a directly related project [3], acoustic emissions from the cell plate are recorded during

  16. An Investigation of Parallel Post-Laminar Flow through Coarse Granular Porous Media with the Wilkins Equation

    Directory of Open Access Journals (Sweden)

    Ashes Banerjee

    2018-02-01

    Full Text Available Behaviour of flow resistance with velocity is still undefined for post-laminar flow through coarse granular media. This can cause considerable errors during flow measurements in situations like rock fill dams, water filters, pumping wells, oil and gas exploration, and so on. Keeping the non-deviating nature of Wilkins coefficients with the hydraulic radius of media in mind, the present study further explores their behaviour to independently varying media size and porosity, subjected to parallel post-laminar flow through granular media. Furthermore, an attempt is made to simulate the post-laminar flow conditions with the help of a Computational Fluid Dynamic (CFD Model in ANSYS FLUENT, since conducting large-scale experiments are often costly and time-consuming. The model output and the experimental results are found to be in good agreement. Percentage deviations between the experimental and numerical results are found to be in the considerable range. Furthermore, the simulation results are statistically validated with the experimental results using the standard ‘Z-test’. The output from the model advocates the importance and applicability of CFD modelling in understanding post-laminar flow through granular media.

  17. Deformation of a 3D granular media caused by fluid invasion

    Science.gov (United States)

    Dalbe, M. J.; Juanes, R.

    2016-12-01

    Multiphase flow in porous media plays a fundamental role in many natural and engineered subsurface processes. The interplay between fluid flow, medium deformation and fracture is essential in geoscience problems as disparate as fracking for unconventional hydrocarbon production, conduit formation and methane venting from lake and ocean sediments, and desiccation cracks in soil. Several experimental and computational studies have shown that the competition between capillary and friction forces can lead to different regimes of deformation, from frictional fingering to hydro-capillary fracturing (Sandnes et al., Nat. Comm. 2011, Holtzman et al., PRL 2012). Most of these investigations have focused, however, on 2D or quasi-2D systems. Here, we develop an experimental set-up that allows us to observe two-phase flow in a fully 3D granular bed and measure the fluid pressure while controlling the level of confining stress. We use an index matching technique to directly visualize the injection of a liquid in a granular media saturated with another, immiscible liquid. We extract the deformation the whole granular bulk as well as at the particle level. Our results show the existence of different regimes of invasion patterns depending on key dimensionless groups that control the system.

  18. Characteristics of thermally assisted magnetic recording in granular perpendicular media

    International Nuclear Information System (INIS)

    Shiino, Hirotaka; Kawana, Mayumi; Miyashita, Eiichi; Hayashi, Naoto; Watanabe, Sadayuki

    2009-01-01

    The effect of thermally assisted magnetic recording using granular perpendicular media with a single-pole-trimmed head has been investigated. A read/write experiment using a spin stand in which the media were heated by laser irradiation demonstrated that the track average amplitude strongly depends on both the position of the write head relative to the center of the laser spot in the down-track direction and on the laser power. Although the signal-to-noise ratio increased with the coercivity of the media, the increment was small; this is thought to be caused by an increase in the switching field distribution of the media with temperature. Our results suggest that the magnetic constant of the media must be optimized with respect to the temperature of writing in order for high-density thermally assisted magnetic recording to be realized

  19. Gas Dispersion in Granular Porous Media under Air-Dry and Wet Conditions

    DEFF Research Database (Denmark)

    Naveed, Muhammad; Hamamoto, S; Kawamoto, K

    2012-01-01

    Subsurface gaseous-phase transport is governed by three gas transport parameters: the air permeability coefficient (ka), gas diffusion coefficient (DP), and gas dispersion coefficient (DH). Among these, DH is the least understood due to hitherto limited research into the relationship between gas...... dispersion and soil physical characteristics. In this study, a series of advection–dispersion experiments was performed on granular porous media to identify the effects of soil column dimensions (length and diameter), particle size and shape, dry bulk density, and moisture content on the magnitude of gas...... dispersion. Glass beads and various sands of different shapes (angular and rounded) with mean particle diameters (d50) ranging from 0.19 to 1.51 mm at both air-dry and variable moisture contents were used as granular porous media. Gas dispersion coefficients and gas dispersivities (a = DH/v, where v...

  20. Measurement of magnetic property of FePt granular media at near Curie temperature

    International Nuclear Information System (INIS)

    Yang, H.Z.; Chen, Y.J.; Leong, S.H.; An, C.W.; Ye, K.D.; Hu, J.F.

    2017-01-01

    The characterization of the magnetic switching behavior of heat assisted magnetic recording (HAMR) media at near Curie temperature (T_c) is important for high density recording. In this study, we measured the magnetic property of FePt granular media (with room temperature coercivity ~25 kOe) at near T_c with a home built HAMR testing instrument. The local area of HAMR media is heated to near T_c by a flat-top optical heating beam. The magnetic property in the heated area was in-situ measured by a magneto-optic Kerr effect (MOKE) testing beam. The switching field distribution (SFD) and coercive field (H_c) of the FePt granular media and their dependence on the optical heating power at near T_c were studied. We measured the DC demagnetization (DCD) signal with pulsed laser heating at different optical powers. We also measured the T_c distribution of the media by measuring the AC magnetic signal as a function of optical heating power. In a summary, we studied the SFD, H_c of the HAMR media at near T_c in a static manner. The present methodology will facilitate the HAMR media testing. - Highlights: • A flat-top optical beam homogeneously heats up HAMR media to near T_c. • When H_c of media drops to 5 kOe with optical heating, SFD is measured to be 0.6. • H_c, SFD, M_s of HAMR media at near T_c are measured with the methodology.

  1. Solitary Wave Interactions in Granular Media

    Institute of Scientific and Technical Information of China (English)

    WEN Zhen-Ying; WANG Shun-Jin; ZHANG Xiu-Ming; LI Lei

    2007-01-01

    We numerically study the interactions of solitary waves in granular media, by considering a chain of beads, which repel upon contact via the Hertz-type potential, V ∝δn, with 5/2 ≤n≤3 and δ≥0,δbeing the bead-bead overlap. There are two collision types of solitary waves, overtaking collision and head-on collision, in the chain of beads. Our quantitative results show that after collision the large solitary wave gains energy and the small one loses energy for overtaking type while the large one loses energy, and the small one gains energy for head-on type. The scattering effects decrease with n for overtaking collision whereas increase with n for head-on collision.

  2. Measurement of magnetic property of FePt granular media at near Curie temperature

    Energy Technology Data Exchange (ETDEWEB)

    Yang, H.Z., E-mail: YANG_Hongzhi@dsi.a-star.edu.sg; Chen, Y.J.; Leong, S.H.; An, C.W.; Ye, K.D.; Hu, J.F.

    2017-02-01

    The characterization of the magnetic switching behavior of heat assisted magnetic recording (HAMR) media at near Curie temperature (T{sub c}) is important for high density recording. In this study, we measured the magnetic property of FePt granular media (with room temperature coercivity ~25 kOe) at near T{sub c} with a home built HAMR testing instrument. The local area of HAMR media is heated to near T{sub c} by a flat-top optical heating beam. The magnetic property in the heated area was in-situ measured by a magneto-optic Kerr effect (MOKE) testing beam. The switching field distribution (SFD) and coercive field (H{sub c}) of the FePt granular media and their dependence on the optical heating power at near T{sub c} were studied. We measured the DC demagnetization (DCD) signal with pulsed laser heating at different optical powers. We also measured the T{sub c} distribution of the media by measuring the AC magnetic signal as a function of optical heating power. In a summary, we studied the SFD, H{sub c} of the HAMR media at near T{sub c} in a static manner. The present methodology will facilitate the HAMR media testing. - Highlights: • A flat-top optical beam homogeneously heats up HAMR media to near T{sub c}. • When H{sub c} of media drops to 5 kOe with optical heating, SFD is measured to be 0.6. • H{sub c}, SFD, M{sub s} of HAMR media at near T{sub c} are measured with the methodology.

  3. Elastic Nonlinear Response in Granular Media Under Resonance Conditions

    Science.gov (United States)

    Jia, X.; Johnson, P. A.

    2004-12-01

    We are studying the elastic linear and nonlinear behavior of granular media using dynamic wave methods. In the work presented here, our goal is to quantify the elastic nonlinear response by applying wave resonance. Resonance studies are desirable because they provide the means to easily study amplitude dependencies of elastic nonlinear behavior and thus to characterize the physical nature of the elastic nonlinearity. This work has implications for a variety of topics, in particular, the in situ nonlinear response of surface sediments. For this work we constructed an experimental cell in which high sensitivity dynamic resonance studies were conducted using granular media under controlled effective pressure. We limit our studies here to bulk modes but have the capability to employ shear waves as well. The granular media are composed of glass beads held under pressure by a piston, while applying resonance waves from transducers as both the excitation and the material probe. The container is closed with two fitted pistons and a normal load is applied to the granular sample across the top piston. Force and displacement are measured directly. Resonant frequency sweeps with frequencies corresponding to the fundamental bulk mode are applied to the longitudinal source transducer. The pore pressure in the system is 1 atm. The glass beads used in our experiments are of diameter 0.5 mm, randomly deposited in a duralumin cylinder of diameter 30 mm and height of 15 mm. This corresponds to a granular skeleton acoustic wave velocity of v ª 750m/s under 50 N of force [0.07 Mpa]. The loaded system gives fundamental mode resonances in the audio frequency band at half a wavelength where resonance frequency is effective-pressure dependent. The volume fraction of glass beads thus obtained is found to be 0.63 ± 0.01. Plane-wave generating and detecting transducers of diameter 30 mm are placed on axis at the top and bottom of the cylindrical container in direct contact with the glass

  4. Fuel micro-mechanics: homogenization, cracking, granular media

    International Nuclear Information System (INIS)

    Monerie, Yann

    2010-01-01

    This work summarizes about fifteen years of research in the field of micro-mechanics of materials. Emphasis is placed on the most recent work carried out in the context of nuclear safety. Micro-mechanics finds a natural place there, aiming to predict the behavior of heterogeneous materials with an evolving microstructure. The applications concerned mainly involve the nuclear fuel and its tubular cladding. The uranium dioxide fuel is modeled, according to the scales under consideration, as a porous ceramic or a granular medium. The strongly irradiated Zircaloy claddings are identified with a composite medium with a metal matrix and a gradient of properties. The analysis of these classes of material is rich in problems of a more fundamental nature. Three main themes are discussed: 1/ Homogenization, 2/ cracking, rupture and fragmentation, 3/ discrete media and fluid-grain couplings. Homogenization: The analytical scale change methods proposed aim to estimate or limit the linear and equivalent nonlinear behaviors of isotropic porous media and anisotropic composites with a metal matrix. The porous media under consideration are saturated or drained, with a compressible or incompressible matrix, and have one or two scales of spherical or ellipsoid pores, or cracks. The composites studied have a macroscopic anisotropy related to that of the matrix, and to the shape and spatial distribution of the inclusions. Thermoelastic, elastoplastic, and viscoplastic behaviors and ductile damage of these media are examined using different techniques: extensions of classic approaches, linear in particular, variational approaches and approaches using elliptical potentials with thermally activated elementary mechanisms. The models developed are validated on numerical finite element simulations, and their functional relevance is illustrated in comparison to experimental data obtained from the literature. The significant results obtained include a plasticity criterion for Gurson matrix

  5. Double-layered perpendicular magnetic recording media of granular-type FePt-MgO films

    International Nuclear Information System (INIS)

    Zhang Zhengang; Singh, Amarendra K.; Yin Jinhua; Perumal, A.; Suzuki, Takao

    2005-01-01

    The recording performance of double-layered granular-type FePt-MgO perpendicular magnetic recording media fabricated onto glass discs by sputtering is investigated. The (0 0 1)-textured FePt granular films are obtained by annealing FePt/MgO multilayers. Three different multilayer structures are compared in their magnetic properties and recording SNR performances. To evaluate thermal stability property of these granular-type FePt disks, the time-dependent magnetic force microscope (MFM) signal from the written bits on one of these disks is recorded in the temperature range 25-200 degree sign C. The signal decay at high observation temperature is interpreted based on the temperature dependence of magnetic anisotropy (K u )

  6. The effect of capped layer thickness on switching behavior in perpendicular CoCrPt based coupled granular/continuous media

    International Nuclear Information System (INIS)

    Li, W.M.; Lim, W.K.; Shi, J.Z.; Ding, J.

    2013-01-01

    A systematic investigation of magnetic switching behavior of CoCrPt based capped media (perpendicularly coupled granular/continuous (CGC) media consisting of granular CoCrPt:SiO 2 TiO 2 Ta 2 O 5 /capped CoCrPt(B)) is performed by varying the thickness of the capped layer from 0 to 9 nm. The microscopic structures of CGC media with different thickness of capped layer are examined by transmission electron microscope. We find out that CoCrPt magnetic grains are separated by nonmagnetic oxide grain boundaries. Grain size and grain boundary are about 8.9 nm and 2 nm, respectively. The nonmagnetic oxide grain boundaries in the granular layer do not disappear immediately at the interface between the granular and capped layers. The amorphous grain boundary phase in the granular layer propagates to the top surface of the capped layer. After capping with the CoCrPt(B) layer, the grain size at the surface of CGC structure increases and the grain boundary decreases. Both coercivity and intergranular exchange coupling of the CGC media are investigated by Polar magneto-optic Kerr effect magnetometer and alternating gradient force magnetometer. Although H c apparently decreases at thicker capped layer, no obvious variation of macroscopic switching field distribution (SFD/H c ) is observed. We separate intrinsic switching field distribution from intergranular interactions. The investigation of reduced intrinsic SFD/H c and increased hysteresis loop slope at coercivity, suggests that improvement of absolute switching field distribution (SFD) is caused by both strong intergranular exchange coupling and uniform grain size. Micromagnetic simulation results further verify our conclusion that the capped layer in CGC media is not uniformly continuous but has some granular nature. However, grains in the CoCrPt(B) capped layer is not absolutely isolated, strong exchange coupling exists between grains. - Highlights: • In CGC media, CoCrPt magnetic grains are separated by nonmagnetic oxide

  7. Submicron and Nanoparticulate Matter Removal by HEPA-Rated Media Filters and Packed Beds of Granular Materials

    Science.gov (United States)

    Perry, J. L.; Agui, J. H.; Vijayakimar, R

    2016-01-01

    Contaminants generated aboard crewed spacecraft by diverse sources consist of both gaseous chemical contaminants and particulate matter. Both HEPA media filters and packed beds of granular material, such as activated carbon, which are both commonly employed for cabin atmosphere purification purposes have efficacy for removing nanoparticulate contaminants from the cabin atmosphere. The phenomena associated with particulate matter removal by HEPA media filters and packed beds of granular material are reviewed relative to their efficacy for removing fine (less than 2.5 micrometers) and ultrafine (less than 0.01 micrometers) sized particulate matter. Considerations are discussed for using these methods in an appropriate configuration to provide the most effective performance for a broad range of particle sizes including nanoparticulates.

  8. USING VISUAL MEDIA IN TEACHING SPEAKING

    Directory of Open Access Journals (Sweden)

    Ahmad Baidawi

    2016-05-01

    Full Text Available Speaking is considered the most important skill of language especially English because having ability to speak is one of the evidence that someone has good proficiency of the language itself. Therefore, it is very urgent to teach speaking to the students in order that they master it well. To teach speaking, the teacher must design learning activities as well as possible and it also must be supported by various teaching media especially visual media such as pictures, realia, television etc. in order that learning activities is more various, interesting and motivates students to participate actively. The presence of visual media presents different learning experience which can stimulate students to think creatively so that they always get new idea to express when they want to speak. Therefore, the more various the teacher uses the media, the better learning objectives students achieve

  9. Transport of Fluorescently Labeled Hydroxyapatite Nanoparticles in Saturated Granular Media at Environmentally Relevant Concentrations of Surfactants

    Science.gov (United States)

    Little is known about the mobility of engineered nanoparticles (ENPs) in granular media at environmentally relevant concentration of surfactant, which represents a critical knowledge gap in employing ENPs for in-situ remediation of contaminated groundwater. In this study, transpo...

  10. Technological effect of vibroprocessing by flows of organic granular media

    Science.gov (United States)

    Lebedev, V. A.; Shishkina, A. P.; Davydova, I. V.; Morozova, A. V.

    2018-03-01

    The analysis of approaches to modeling of vibrational processing by granulated media is carried out. The vibroprocessing model which provides effective finishing of the surfaces of the parts due to the stone fruit organic media granules is developed. The model is based on the granule flow energy impact on the surface being treated. As the main characteristic of the organic media processing, a specific volumetric metal scrap is used, the physical meaning of which is the increase rate in the thickness of the material removed from the surface at a given velocity and pressure of the medium. It is shown that the metal scrap depends on the medium flow velocity, the height of the loading column of the granular medium, and the conditions for the formation of a medium stationary circulation motion. Based on the analysis of the results of experimental studies of the influence of amplitude-frequency characteristics on the removal of metal in the process of vibroprocessing with abrasive granules, the dependence of the specific volume metal removal is proposed for organic media processing, taking into account the threshold amplitude and frequency of oscillations of the working chamber, at which the effect of surface treatment is observed. The established set of relationships describing the effective conditions for vibroprocessing with stone organic media was obtained using experimental data, which allows us to assume that the model obtained is valid.

  11. Pneumatic fractures in confined granular media.

    Science.gov (United States)

    Eriksen, Fredrik K; Toussaint, Renaud; Turquet, Antoine L; Måløy, Knut J; Flekkøy, Eirik G

    2017-06-01

    We perform experiments where air is injected at a constant overpressure P_{in}, ranging from 5 to 250 kPa, into a dry granular medium confined within a horizontal linear Hele-Shaw cell. The setup allows us to explore compacted configurations by preventing decompaction at the outer boundary, i.e., the cell outlet has a semipermeable filter such that beads are stopped while air can pass. We study the emerging patterns and dynamic growth of channels in the granular media due to fluid flow, by analyzing images captured with a high speed camera (1000 images/s). We identify four qualitatively different flow regimes, depending on the imposed overpressure, ranging from no channel formation for P_{in} below 10 kPa, to large thick channels formed by erosion and fingers merging for high P_{in} around 200 kPa. The flow regimes where channels form are characterized by typical finger thickness, final depth into the medium, and growth dynamics. The shape of the finger tips during growth is studied by looking at the finger width w as function of distance d from the tip. The tip profile is found to follow w(d)∝d^{β}, where β=0.68 is a typical value for all experiments, also over time. This indicates a singularity in the curvature d^{2}d/dw^{2}∼κ∼d^{1-2β}, but not of the slope dw/dd∼d^{β-1}, i.e., more rounded tips rather than pointy cusps, as they would be for the case β>1. For increasing P_{in}, the channels generally grow faster and deeper into the medium. We show that the channel length along the flow direction has a linear growth with time initially, followed by a power-law decay of growth velocity with time as the channel approaches its final length. A closer look reveals that the initial growth velocity v_{0} is found to scale with injection pressure as v_{0}∝P_{in}^{3/2}, while at a critical time t_{c} there is a cross-over to the behavior v(t)∝t^{-α}, where α is close to 2.5 for all experiments. Finally, we explore the fractal dimension of the fully

  12. Preparation and recording characteristics of granular-type perpendicular magnetic recording media with thin intermediate layer

    International Nuclear Information System (INIS)

    Shintaku, K.; Kiya, T.

    2008-01-01

    Granular-type media with thin Ru intermediate layer were prepared on a highly oriented high-B s FeCo soft underlayer (SUL). A CoPt-TiO 2 recording layer on a Ru intermediate layer of only 2 nm had high-crystal orientation, high H c of 6.5 kOe, and a high squareness ratio (SQ) of 0.99. The magnetic property of the SUL was also good. The recording performance was measured for the media with different Ru intermediate thicknesses by using a single-pole-type (SPT) head. The media had large reproduced output even for the Ru intermediate layer thickness of 2 nm

  13. Preparation and recording characteristics of granular-type perpendicular magnetic recording media with thin intermediate layer

    Energy Technology Data Exchange (ETDEWEB)

    Shintaku, K. [Akita Research Institute of Advanced Technology, Akita Prefectural R and D Center, 4-21 Sanuki, Araya, Akita 010-1623 (Japan)], E-mail: shintaku@ait.pref.akita.jp; Kiya, T. [Akita Research Institute of Advanced Technology, Akita Prefectural R and D Center, 4-21 Sanuki, Araya, Akita 010-1623 (Japan)

    2008-11-15

    Granular-type media with thin Ru intermediate layer were prepared on a highly oriented high-B{sub s} FeCo soft underlayer (SUL). A CoPt-TiO{sub 2} recording layer on a Ru intermediate layer of only 2 nm had high-crystal orientation, high H{sub c} of 6.5 kOe, and a high squareness ratio (SQ) of 0.99. The magnetic property of the SUL was also good. The recording performance was measured for the media with different Ru intermediate thicknesses by using a single-pole-type (SPT) head. The media had large reproduced output even for the Ru intermediate layer thickness of 2 nm.

  14. Uniform shock waves in disordered granular matter

    NARCIS (Netherlands)

    Gómez, L.R.; Turner, A.M.; Vitelli, V.

    2012-01-01

    The confining pressure P is perhaps the most important parameter controlling the properties of granular matter. Strongly compressed granular media are, in many respects, simple solids in which elastic perturbations travel as ordinary phonons. However, the speed of sound in granular aggregates

  15. EDMODO AS A MEDIA TO TEACH VOCABULARY

    Directory of Open Access Journals (Sweden)

    Sutrisno Sadji Evenddy

    2016-03-01

    Full Text Available This article aims at intoducing how to use Edmodo to teach vocabulary. Vocabulary is a component of English language. When we are speaking and writing, we need to master vocabulary related to certain topic. Therefore vocabulary is important thing in learning language. But, mastering English vocabularies is not easy. Teacher needs a media to make an interesting teaching-learning process. One of the most accepted trends in the field of teaching vocabulary in a foreign language teaching is Computer-Assisted Language Learning (CALL. CALL has several applications that can be used by the teachers in teaching vocabulary. Computer and mobile telephone internet allow immediate connection to a server. In the internet browser the teachers and students can browse Edmodo. One of media is Edmodo. Edmodo is one of social media which can be operated by students, teachers or lecturers, and parents. It is able to be used to post various assignments and students’ learning achievement, actual discussion topics, video, appointments, and to facilitate students’ polls which are related to teaching learning process.

  16. Discharge flow of a granular media from a silo: effect of the packing fraction and of the hopper angle

    Science.gov (United States)

    Benyamine, Mebirika; Aussillous, Pascale; Dalloz-Dubrujeaud, Blanche

    2017-06-01

    Silos are widely used in the industry. While empirical predictions of the flow rate, based on scaling laws, have existed for more than a century (Hagen 1852, translated in [1] - Beverloo et al. [2]), recent advances have be made on the understanding of the control parameters of the flow. In particular, using continuous modeling together with a mu(I) granular rheology seem to be successful in predicting the flow rate for large numbers of beads at the aperture (Staron et al.[3], [4]). Moreover Janda et al.[5] have shown that the packing fraction at the outlet plays an important role when the number of beads at the apeture decreases. Based on these considerations, we have studied experimentally the discharge flow of a granular media from a rectangular silo. We have varied two main parameters: the angle of the hopper, and the bulk packing fraction of the granular material by using bidisperse mixtures. We propose a simple physical model to describe the effect of these parameters, considering a continuous granular media with a dilatancy law at the outlet. This model predicts well the dependance of the flow rate on the hopper angle as well as the dependance of the flow rate on the fine mass fraction of a bidisperse mixture.

  17. Learning and Teaching Art: Through Social Media

    Science.gov (United States)

    Castro, Juan Carlos

    2012-01-01

    Social media practices are increasingly woven into the everyday lives of teens and adults, becoming a significant part of how they relate, know, and learn. In this article, I present findings from a design-based research study that explored how the dynamics of learning and teaching art shift through social media. Learning and teaching through…

  18. Traffic and Granular Flow ’03

    CERN Document Server

    Luding, Stefan; Bovy, Piet; Schreckenberg, Michael; Wolf, Dietrich

    2005-01-01

    These proceedings are the fifth in the series Traffic and Granular Flow, and we hope they will be as useful a reference as their predecessors. Both the realistic modelling of granular media and traffic flow present important challenges at the borderline between physics and engineering, and enormous progress has been made since 1995, when this series started. Still the research on these topics is thriving, so that this book again contains many new results. Some highlights addressed at this conference were the influence of long range electric and magnetic forces and ambient fluids on granular media, new precise traffic measurements, and experiments on the complex decision making of drivers. No doubt the “hot topics” addressed in granular matter research have diverged from those in traffic since the days when the obvious analogies between traffic jams on highways and dissipative clustering in granular flow intrigued both c- munities alike. However, now just this diversity became a stimulating feature of the ...

  19. A Comparison of Streaming and Microelectrophoresis Methods for Obtaining the zeta Potential of Granular Porous Media Surfaces.

    Science.gov (United States)

    Johnson

    1999-01-01

    The electrokinetic behavior of granular quartz sand in aqueous solution is investigated by both microelectrophoresis and streaming potential methods. zeta potentials of surfaces composed of granular quartz obtained via streaming potential methods are compared to electrophoretic mobility zeta potential values of colloid-sized quartz fragments. The zeta values generated by these alternate methods are in close agreement over a wide pH range and electrolyte concentrations spanning several orders of magnitude. Streaming measurements performed on chemically heterogeneous mixtures of physically homogeneous sand are shown to obey a simple mixing model based on the surface area-weighted average of the streaming potentials associated with the individual end members. These experimental results support the applicability of the streaming potential method as a means of determining the zeta potential of granular porous media surfaces. Copyright 1999 Academic Press.

  20. Anisotropy in cohesive, frictional granular media

    International Nuclear Information System (INIS)

    Luding, Stefan

    2005-01-01

    The modelling of cohesive, frictional granular materials with a discrete particle molecular dynamics is reviewed. From the structure of the quasi-static granular solid, the fabric, stress, and stiffness tensors are determined, including both normal and tangential forces. The influence of the material properties on the flow behaviour is also reported, including relations between the microscopic attractive force and the macroscopic cohesion as well as the dependence of the macroscopic friction on the microscopic contact friction coefficient. Related to the dynamics, the anisotropy of both structure and stress are exponentially approaching the maximum

  1. Repositioning teaching in Nigerian secondary schools using media ...

    African Journals Online (AJOL)

    Repositioning teaching in Nigerian secondary schools using media resources in a digital age. ... Lagos Journal of Library and Information Science ... that the new tools served as an added advantage on the traditional method of teaching and learning, especially in information delivery; channelled through media resources.

  2. Network flow model of force transmission in unbonded and bonded granular media.

    Science.gov (United States)

    Tordesillas, Antoinette; Tobin, Steven T; Cil, Mehmet; Alshibli, Khalid; Behringer, Robert P

    2015-06-01

    An established aspect of force transmission in quasistatic deformation of granular media is the existence of a dual network of strongly versus weakly loaded particles. Despite significant interest, the regulation of strong and weak forces through the contact network remains poorly understood. We examine this aspect of force transmission using data on microstructural fabric from: (I) three-dimensional discrete element models of grain agglomerates of bonded subspheres constructed from in situ synchrotron microtomography images of silica sand grains under unconfined compression and (II) two-dimensional assemblies of unbonded photoelastic circular disks submitted to biaxial compression under constant volume. We model force transmission as a network flow and solve the maximum flow-minimum cost (MFMC) problem, the solution to which yields a percolating subnetwork of contacts that transmits the "maximum flow" (i.e., the highest units of force) at "least cost" (i.e., the dissipated energy from such transmission). We find the MFMC describes a two-tier hierarchical architecture. At the local level, it encapsulates intraconnections between particles in individual force chains and in their conjoined 3-cycles, with the most common configuration having at least one force chain contact experiencing frustrated rotation. At the global level, the MFMC encapsulates interconnections between force chains. The MFMC can be used to predict most of the force chain particles without need for any information on contact forces, thereby suggesting the network flow framework may have potential broad utility in the modeling of force transmission in unbonded and bonded granular media.

  3. Tracing Thermal Creep Through Granular Media

    Science.gov (United States)

    Steinpilz, Tobias; Teiser, Jens; Koester, Marc; Schywek, Mathias; Wurm, Gerhard

    2017-08-01

    A temperature gradient within a granular medium at low ambient pressure drives a gas flow through the medium by thermal creep. We measured the resulting air flow for a sample of glass beads with particle diameters between 290 μ m and 420 μ m for random close packing. Ambient pressure was varied between 1 Pa and 1000 Pa. The gas flow was quantified by means of tracer particles during parabolic flights. The flow varies systematically with pressure between 0.2 cm/s and 6 cm/s. The measured flow velocities are in quantitative agreement to model calculations that treat the granular medium as a collection of linear capillaries.

  4. Effect of deformation on the thermal conductivity of granular porous media with rough grain surface

    Science.gov (United States)

    Askari, Roohollah; Hejazi, S. Hossein; Sahimi, Muhammad

    2017-08-01

    Heat transfer in granular porous media is an important phenomenon that is relevant to a wide variety of problems, including geothermal reservoirs and enhanced oil recovery by thermal methods. Resistance to flow of heat in the contact area between the grains strongly influences the effective thermal conductivity of such porous media. Extensive experiments have indicated that the roughness of the grains' surface follows self-affine fractal stochastic functions, and thus, the contact resistance cannot be accounted for by models based on smooth surfaces. Despite the significance of rough contact area, the resistance has been accounted for by a fitting parameter in the models of heat transfer. In this Letter we report on a study of conduction in a packing of particles that contains a fluid of a given conductivity, with each grain having a rough self-affine surface, and is under an external compressive pressure. The deformation of the contact area depends on the fractal dimension that characterizes the grains' rough surface, as well as their Young's modulus. Excellent qualitative agreement is obtained with experimental data. Deformation of granular porous media with grains that have rough self-affine fractal surface is simulated. Thermal contact resistance between grains with rough surfaces is incorporated into the numerical simulation of heat conduction under compressive pressure. By increasing compressive pressure, thermal conductivity is enhanced more in the grains with smoother surfaces and lower Young's modulus. Excellent qualitative agreement is obtained with the experimental data.

  5. Reduction of intergranular exchange coupling and grain size for high Ku CoPt-based granular media: Metal-oxide buffer layer and multiple oxide boundary materials

    Science.gov (United States)

    Tham, Kim Kong; Kushibiki, Ryosuke; Kamada, Tomonari; Hinata, Shintaro; Saito, Shin

    2018-05-01

    Investigation of magnetic properties and microstructure of granular media with various multiple oxides as the grain boundary material is reported. Saturation magnetization (Ms), uniaxial magnetocrystalline anisotropy (Ku), and magnetic grain diameter (GD) of the granular media show linear correlation with volume weighted average for melting point (Tm) of each oxides (Tmave). Ku of magnetic grains (Kugrain) shows a trade-off relation with GD that it is a big challenge to satisfy both high Kugrain and small GD by only controlling Tmave. To obtain a granular medium with appropriate Kugrain, GD, and low degree of intergranular exchange coupling, the combination of Tmave control of grain boundary material by mixing oxides and employment of a buffer layer are required. Here the degree of intergranular exchange coupling is estimated from the slope of M-H loop at around coercivity (α). By applying this technique, a typical granular medium with Kugrain of 1.0×107 erg/cm3, GD of 5.1 nm, and α of 1.2 is realized.

  6. Influence of inhomogeneous coercivities on media noise in granular perpendicular media investigated by using magnetic force microscopy

    International Nuclear Information System (INIS)

    Bai, J.; Takahoshi, H.; Ito, H.; Rheem, Y.W.; Saito, H.; Ishio, S.

    2004-01-01

    We investigated the influence of the inhomogeneous coercivities on the media noise in a CoPtCr-SiO 2 granular perpendicular magnetic recording medium via ex situ and in situ magnetic force microscopy (MFM) techniques. The ex situ MFM analyses exhibited that transition zigzags contributed to strong magnetic clusters in noise images, and thus resulted in dominant component of the media noise. According to the in situ MFM measurements, it was suggested that an amount of magnetic grains inside a microscopic area reversed like one magnetic ''particle because of strong inter-grain exchange coupling, and that these microscopic areas showed their local magnetic switching behaviors. A mathematic transformation was used to obtain approximately the magnetization distribution in recording layer. And the individual microscopic areas inside recorded bits were compared quasi-quantitatively with those leading large transition zigzags in magnetization switching behaviors. It was indicated that the inhomogeneous coercivities is one of crucial reasons of the medium noise in the perpendicular magnetic recording

  7. Guidelines for Teaching Non-Verbal Communications Through Visual Media

    Science.gov (United States)

    Kundu, Mahima Ranjan

    1976-01-01

    There is a natural unique relationship between non-verbal communication and visual media such as television and film. Visual media will have to be used extensively--almost exclusively--in teaching non-verbal communications, as well as other methods requiring special teaching skills. (Author/ER)

  8. Dynamics of electrostatically driven granular media: Effects of humidity

    International Nuclear Information System (INIS)

    Howell, D. W.; Aronson, Igor S.; Crabtree, G. W.

    2001-01-01

    We performed experimental studies of the effect of humidity on the dynamics of electrostatically driven granular materials. Both conducting and dielectric particles undergo a phase transition from an immobile state (granular solid) to a fluidized state (granular gas) with increasing applied field. Spontaneous precipitation of solid clusters from the gas phase occurs as the external driving is decreased. The clustering dynamics in conducting particles is primarily controlled by screening of the electric field but is aided by cohesion due to humidity. It is shown that humidity effects dominate the clustering process with dielectric particles

  9. Reduction of intergranular exchange coupling and grain size for high Ku CoPt-based granular media: Metal-oxide buffer layer and multiple oxide boundary materials

    Directory of Open Access Journals (Sweden)

    Kim Kong Tham

    2018-05-01

    Full Text Available Investigation of magnetic properties and microstructure of granular media with various multiple oxides as the grain boundary material is reported. Saturation magnetization (Ms, uniaxial magnetocrystalline anisotropy (Ku, and magnetic grain diameter (GD of the granular media show linear correlation with volume weighted average for melting point (Tm of each oxides (Tmave. Ku of magnetic grains (Kugrain shows a trade-off relation with GD that it is a big challenge to satisfy both high Kugrain and small GD by only controlling Tmave. To obtain a granular medium with appropriate Kugrain, GD, and low degree of intergranular exchange coupling, the combination of Tmave control of grain boundary material by mixing oxides and employment of a buffer layer are required. Here the degree of intergranular exchange coupling is estimated from the slope of M-H loop at around coercivity (α. By applying this technique, a typical granular medium with Kugrain of 1.0×107 erg/cm3, GD of 5.1 nm, and α of 1.2 is realized.

  10. Long-range interactions in dilute granular systems

    NARCIS (Netherlands)

    Müller, M.K

    2008-01-01

    In this thesis, on purpose, we focussed on the most challenging, longest ranging potentials. We analyzed granular media of low densities obeying 1/r long-range interaction potentials between the granules. Such systems are termed granular gases and differ in their behavior from ordinary gases by

  11. Effects of acoustic waves on stick-slip in granular media and implications for earthquakes

    Science.gov (United States)

    Johnson, P.A.; Savage, H.; Knuth, M.; Gomberg, J.; Marone, Chris

    2008-01-01

    It remains unknown how the small strains induced by seismic waves can trigger earthquakes at large distances, in some cases thousands of kilometres from the triggering earthquake, with failure often occurring long after the waves have passed. Earthquake nucleation is usually observed to take place at depths of 10-20 km, and so static overburden should be large enough to inhibit triggering by seismic-wave stress perturbations. To understand the physics of dynamic triggering better, as well as the influence of dynamic stressing on earthquake recurrence, we have conducted laboratory studies of stick-slip in granular media with and without applied acoustic vibration. Glass beads were used to simulate granular fault zone material, sheared under constant normal stress, and subject to transient or continuous perturbation by acoustic waves. Here we show that small-magnitude failure events, corresponding to triggered aftershocks, occur when applied sound-wave amplitudes exceed several microstrain. These events are frequently delayed or occur as part of a cascade of small events. Vibrations also cause large slip events to be disrupted in time relative to those without wave perturbation. The effects are observed for many large-event cycles after vibrations cease, indicating a strain memory in the granular material. Dynamic stressing of tectonic faults may play a similar role in determining the complexity of earthquake recurrence. ??2007 Nature Publishing Group.

  12. Acoustic probing of elastic behavior and damage in weakly cemented granular media

    Science.gov (United States)

    Langlois, V.; Jia, X.

    2014-02-01

    We investigate the elastic behavior and damage of weakly cemented granular media under external load with ultrasound. The cementation controlled experiments are performed by freezing the capillary liquid at the bead contact in a dense glass or polymeric [poly(methyl methacrylate)] bead pack wet by tetradecane of volume fraction ϕ = 0.1%-4%. When the pendular rings are solidified, an abrupt increase by a factor of 2 in the compressional wave velocity is observed. We interpret the data in terms of effective medium models in which the contact stiffnesses are derived by either a bonded contact model [P. J. Digby, J. Appl. Mech. 48, 803 (1981), 10.1115/1.3157738] or a cemented contact model [J. Dvorkin, A. Nur, and H. Yin, Mech. Mater. 18, 351 (1994), 10.1016/0167-6636(94)90044-2]. The former fails to quantitatively account for the results with a soft cement relative to the grain, whereas the latter considering the mechanical properties of the cement does apply. Moreover, we monitor the irreversible behavior of the cemented granular packs under moderate uniaxial loading (cemented materials is accompanied by a compressional wave velocity decrease up to 60%, likely due to the fractures induced at the grain-cement interfaces.

  13. Laser-Doppler acoustic probing of granular media with in-depth property gradient and varying pore pressures

    International Nuclear Information System (INIS)

    Bodet, L.; Dhemaied, A.; Mourgues, R.; Tournat, V.; Rejiba, F.

    2012-01-01

    Non-contacting ultrasonic techniques recently proved to be efficient in the physical modeling of seismic-wave propagation at various application scales, as for instance in the context of geological analogue and seismic modeling. An innovative experimental set-up is proposed here to perform laser-Doppler acoustic probing of unconsolidated granular media with varying pore pressures. The preliminary experiments presented here provide reproducible results and exploitable data, thus validating both the proposed medium preparation and pressure gradient generation procedure.

  14. Strain localisation in granular media

    OpenAIRE

    Desrues , Jacques

    1984-01-01

    This study is devoted to strain localisation in Granular materials. Both experimental and theoretical results have been obtained.The first part of the thesis is a review of the methods and theories about rupture in sols mechanics and more generally, in solid mechanics. The classical framework of Shear Band analysis is presented, and the main results available for different classes of materials are discussed.The second part describes an experimental study of strain localisation in sand specime...

  15. Teaching social media the can-do guide

    CERN Document Server

    Kirchhoff, Liz

    2014-01-01

    Sharing social media expertise with library clientele is a natural way for libraries to support their communities-and increase their relevance. This book provides a roadmap for librarians who wish to offer this service but need to brush up on their own social media skills or learn how to cover the topics in a classroom situation. Although there are many books on social media, this volume is unique because it presents complete teaching scripts that can be adapted for various classroom situations along with general guidelines and tips. You'll find general advice on social media as well as su

  16. Experimental and Modeling Study on Detachment of Silver Nanoparticles in Saturated Granular Media

    Science.gov (United States)

    Kim, I.; Jeon, C. H.; Lawler, D. F.

    2017-12-01

    The detachment of citrate-capped silver nanoparticles (AgNPs) previously captured in a column packed with 350-μm glass beads was investigated either by increasing the hydrodynamic force (filtration velocity) or by reducing electrosteric attraction. Overall, the physical enforcement showed negligible (0.4 0.7%) release of attached AgNPs while the chemically-driven force resulted in the noticeable release up to 25.5% of attached AgNPs. Among the chemical parameters tested in this study, Na ionic strength reduction clearly demonstrated the reversible deposition in the secondary energy minimum of classical DLVO theory, yielding the most significant release of the attached AgNPs. The immediate and transient AgNP release after the ionic strength reduction further corroborated the weak deposition. However, an insignificant release was observed with Ca ionic strength reduction due to the strong Ca-citrate complexation and the subsequent deposition in the primary energy minimum; calculations indicated that the depth of the secondary energy minimum was only 1/10 that of the Na ion case. The natural organic matter (NOM) coating on both AgNPs and granular media resulted in approximately 6.1% greater AgNP release compared to the case without NOM coating, indicating additional weak deposition due to the reduced steric attraction between AgNPs and granular media. A modified filtration model in agreement with the experimental data provided the estimated detachment coefficient as a transient AgNP releasing capacity independent of the amount of attached AgNPs. The marginal difference between the detachment coefficients from Na ionic strength reduction and NOM coating indicates the release potential by NOM coating was possibly underestimated in the experimental study due to a lesser amount of the initially attached AgNPs. The findings provide insights into chemical factors on possible reentrainment behavior of the engineered nanoparticles in soil and groundwater contamination.

  17. THE USE OF TEACHING MEDIA TO ENHANCE STUDENTS’ SKILL IN WRITING FUNCTIONAL TEXTS

    Directory of Open Access Journals (Sweden)

    Yusuf Hidayat

    2017-04-01

    Full Text Available Teaching writing functional texts usually tends to be conventionally applied. Most teachers tend to emphasize their teaching process traditionally without paying attention to the teaching media which can be used to help students’ success achieving the goal of learning. This paper is aimed at investigating the role of teaching media in enhancing students’ skill in writing functional texts. In this regard, classroom action research (CAR was employed as the method in this study. This study is intended to answer the following research questions: (1 Is teaching media effective for enhancing students’ skill in writing functional texts? (2 To what extent does teaching media enhance students’ skill in writing functional texts? Through the process of teaching and learning activities, in cycle 1, the writers taught writing functional texts through conventional teaching, they then gave a test on functional text to the students. Additionally, to confirm the writers’ belief to the students’ real writing proficiency, they then gave them TOEFL written test model. Next, in cycle 2, the writers taught the students by using teaching media. Finally, the writers gave them a test of writing functional text. After undertaking several tests in cycle 1, students got average score 56.60, and in cycle 2, they got 65.08. Thus, there was an improvement of the average score. In addition, the students’ enthusiasm also improved.

  18. Inspecting Taiwan’s Media Education for Children from the Teaching Cases between 1999-2011

    Directory of Open Access Journals (Sweden)

    Huiping Huang

    2016-10-01

    Full Text Available Media education has often begun as a defensive enterprise, but cultivating media production capabilities has been a trend today. This study analyzes 53 teaching cases of media education for elementary school children in Taiwan. Results show that teaching cases increase over the years and instructors use both independent and infusion curricula to implement media education with the latter mostly infusing in social studies. Instructors mostly use discussions and lectures in class and conduct textual analyses to interpret commercialization and gender issues in the media. Recently, more creative teaching strategies such as simulation and practical training have been adopted. Also, students perform better understanding of media representation and the audience role. Overall, media education for school children has gained more attention in Taiwan and reveals a track gradually shifting from the protectionist to preparation models. To orient children in the digital age, media education needs to adopt more innovative teaching methods and to empower children to access digital media.

  19. Lizard locomotion in heterogeneous granular media

    Science.gov (United States)

    Schiebel, Perrin; Goldman, Daniel

    2014-03-01

    Locomotion strategies in heterogeneous granular environments (common substrates in deserts), are relatively unexplored. The zebra-tailed lizard (C. draconoides) is a useful model organism for such studies owing to its exceptional ability to navigate a variety of desert habitats at impressive speed (up to 50 body-lengths per second) using both quadrapedal and bidepal gaits. In laboratory experiments, we challenge the lizards to run across a field of boulders (2.54 cm diameter glass spheres or 3.8 cm 3D printed spheres) placed in a lattice pattern and embedded in a loosely packed granular medium of 0.3 mm diameter glass particles. Locomotion kinematics of the lizard are recorded using high speed cameras, with and without the scatterers. The data reveals that unlike the lizard's typical quadrupedal locomotion using a diagonal gait, when scatterers are present the lizard is most successful when using a bipedal gait, with a raised center of mass (CoM). We propose that the kinematics of bipedal running in conjunction with the lizard's long toes and compliant hind foot are the keys to this lizard's successful locomotion in the presence of such obstacles. NSF PoLS

  20. On the submerging of a spherical intruder into granular beds

    Directory of Open Access Journals (Sweden)

    Wu Chuan-Yu

    2017-01-01

    Full Text Available Granular materials are complex systems and their mechanical behaviours are determined by the material properties of individual particles, the interaction between particles and the surrounding media, which are still incompletely understood. Using an advanced discrete element method (DEM, we simulate the submerging process of a spherical projectile (an intruder into granular materials of various properties with a zero penetration velocity (i.e. the intruder is touching the top surface of the granular bed and released from stationary and examine its settling behaviour. By systematically changing the density and size of the intruder and the particle density (i.e. the density of the particles in the granular bed, we find that the intruder can sink deep into the granular bed even with a zero penetration velocity. Furthermore, we confirm that under certain conditions the granular bed can behave like a Newtonian liquid and the submerging intruder can reach a constant velocity, i.e. the terminal velocity, identical to the settling of a sphere in a liquid, as observed experimentally. A mathematical model is also developed to predict the maximum penetration depth of the intruder. The model predictions are compared with experimental data reported in the literature,good agreement was obtained, demonstrating the model can accurately predict the submerging behaviour of the intruder in the granular media.

  1. Similitude study of a moving bed granular filter

    Energy Technology Data Exchange (ETDEWEB)

    Robert C. Brown; Huawei Shi; Gerald Colver; Saw-Choon Soo [Iowa State University, IA (United States)

    2003-12-10

    The goal of this study was to evaluate the performance of a moving bed granular filter designed for hot gas clean up. This study used similitude theory to devise experiments that were conducted at near-ambient conditions while simulating the performance of filters operated at elevated temperatures and pressures (850{sup o}C and 1000 kPa). These experiments revealed that the proposed moving bed granular filter can operate at high collection efficiencies, typically exceeding 99%, and low pressure drops without the need for periodic regeneration through the use of a continuous flow of fresh granular filter media in the filter. In addition, important design constraints were discovered for the successful operation of the proposed moving bed granular filter.

  2. Media Usage in Post-Secondary Education and Implications for Teaching and Learning

    Directory of Open Access Journals (Sweden)

    G. Gidion

    2014-12-01

    Full Text Available The Web 2.0 has permeated academic life. The use of online information services in post-secondary education has led to dramatic changes in faculty teaching methods as well as in the learning and study behavior of students. At the same time, traditional information media, such as textbooks and printed handouts, still form the basic pillars of teaching and learning. This paper reports the results of a survey about media usage in teaching and learning conducted with Western University students and instructors, highlighting trends in the usage of new and traditional media in higher education by instructors and students. In addition, the survey comprises part of an international research program in which 20 universities from 10 countries are currently participating. Further, the study will hopefully become a part of the ongoing discussion of practices and policies that purport to advance the effective use of media in teaching and learning.

  3. Transport of ARS-labeled hydroxyapatite nanoparticles in saturated granular media is influenced by surface charge variability even in the presence of humic acid

    Science.gov (United States)

    Hydroxyapatite nanoparticles (nHAP) are increasingly being used to remediate soils and water polluted by metals and radionuclides. The transport and retention of Alizarin red S (ARS)-labeled nHAP in water-saturated granular media were investigated. Experiments were conducted over a range of ionic ...

  4. Media Literacy in Action? What Are We Teaching in Introductory College Media Studies Courses?

    Science.gov (United States)

    Ashley, Seth

    2015-01-01

    An introductory media studies course is a staple of post-secondary education. What are instructors teaching in this course, and to what extent are the principles of media literacy education being incorporated into this likely home? This article reports the findings of a small survey of instructors, who describe aspects of their course content and…

  5. Acoustic waves in granular materials

    NARCIS (Netherlands)

    Mouraille, O.J.P.; Luding, Stefan

    2008-01-01

    Dynamic simulations with discrete elements are used to obtain more insight into the wave propagation in dense granular media. A small perturbation is created on one side of a dense, static packing and examined during its propagation until it arrives at the opposite side. The influence of

  6. Violence and the Media: Teaching Strategies and a Rationale.

    Science.gov (United States)

    Gathercoal, Paul

    This paper suggests teaching strategies for grades 4 through 12 that examine the commercial media and their messages as agenda setters, i.e., as mechanisms for selecting social issues, establishing their importance, and defining socially acceptable attitudes and responses to those issues. The strategies also explore how the media can create biased…

  7. Teaching Social Media Journalism: Challenges and Opportunities for Future Curriculum Design

    Science.gov (United States)

    Bor, Stephanie E.

    2014-01-01

    In response to the growing demand for digitally competent employees in the news media industry, journalism schools are cautiously integrating social media reporting into their curriculum. This study explores techniques for teaching news reporting on social media platforms focusing on challenges and opportunities for learning engagement that…

  8. Micro origins for macro behavior in granular media

    NARCIS (Netherlands)

    Zhao, J.; Jiang, M.; Soga, K.; Luding, Stefan

    2016-01-01

    We report the latest advances in understanding, characterization and modeling of key micro mechanisms and origins underpinning the interesting and complex macroscopic behavior of granular matter. Included in this Topical Collection are novel theories, innovative experimental tools and new numerical

  9. A didactical structural model – linking analysis of teaching and analysis of educational media

    DEFF Research Database (Denmark)

    Graf, Stefan Ting

    1. Gap between general didactics and textbook/media research There seems to be a gap between general didactics (theory of teaching) and research in textbooks or educational media in general at least in the Nordic and German speaking countries. General didactic and their models seem to underestimate...... related questions (e.g. readability) without establishing a link to what is useful for the teacher’s tasks both on the level of preparation, practice and reflection, i.e. without an explicit theory of teaching. 2. Media in general didactics I will discuss the status of media in some current models...... of reflection in general didactics (Hiim/Hippe, Meyer, Klafki) and present a reconstruction of a didactical model of structure (Strukturmodel), whose counterstones are ‘intentional content’, ‘media/expression’ and ‘teaching method/activity’. The inclusion of media/expression in the model resumes a seemingly...

  10. In situ bioremediation: A network model of diffusion and flow in granular porous media

    Energy Technology Data Exchange (ETDEWEB)

    Griffiths, S.K.; Nilson, R.H.; Bradshaw, R.W.

    1997-04-01

    In situ bioremediation is a potentially expedient, permanent and cost- effective means of waste site decontamination. However, permeability reductions due to the transport and deposition of native fines or due to excessive microorganism populations may severely inhibit the injection of supplemental oxygen in the contamination zone. To help understand this phenomenon, we have developed a micro-mechanical network model of flow, diffusion and particle transport in granular porous materials. The model differs from most similar models in that the network is defined by particle positions in a numerically-generated particle array. The model is thus widely applicable to computing effective transport properties for both ordered and realistic random porous media. A laboratory-scale apparatus to measure permeability reductions has also been designed, built and tested.

  11. Uniform shock waves in disordered granular matter.

    Science.gov (United States)

    Gómez, Leopoldo R; Turner, Ari M; Vitelli, Vincenzo

    2012-10-01

    The confining pressure P is perhaps the most important parameter controlling the properties of granular matter. Strongly compressed granular media are, in many respects, simple solids in which elastic perturbations travel as ordinary phonons. However, the speed of sound in granular aggregates continuously decreases as the confining pressure decreases, completely vanishing at the jamming-unjamming transition. This anomalous behavior suggests that the transport of energy at low pressures should not be dominated by phonons. In this work we use simulations and theory to show how the response of granular systems becomes increasingly nonlinear as pressure decreases. In the low-pressure regime the elastic energy is found to be mainly transported through nonlinear waves and shocks. We numerically characterize the propagation speed, shape, and stability of these shocks and model the dependence of the shock speed on pressure and impact intensity by a simple analytical approach.

  12. Social Media and Teaching-Learning: Connecting or Distancing?

    Science.gov (United States)

    Yancey, Nan Russell

    2017-10-01

    As new ideas and new ways of connecting seemingly surface ever more quickly, faculty face the daunting task of using emerging technology in the teaching-learning endeavor while honoring the presence of teacher with learner. The focus of this column is on using social media as a teaching-learning tool in the shared journey of coming to know, which is so essential for the aspiring nurse. While opportunities for using teaching-learning technologies abound and are ever-changing, faculty are challenged to cocreate a learner-focused journey of coming to know, without allowing the technology to become the focus.

  13. Force and flow at the onset of drag in plowed granular media.

    Science.gov (United States)

    Gravish, Nick; Umbanhowar, Paul B; Goldman, Daniel I

    2014-04-01

    We study the transient drag force FD on a localized intruder in a granular medium composed of spherical glass particles. A flat plate is translated horizontally from rest through the granular medium to observe how FD varies as a function of the medium's initial volume fraction, ϕ. The force response of the granular material differs above and below the granular critical state, ϕc, the volume fraction which corresponds to the onset of grain dilatancy. For ϕϕc, FD rapidly rises to a maximum and then decreases over further displacement. The maximum force for ϕ>ϕc increases with increasing drag velocity. In quasi-two-dimensional drag experiments, we use granular particle image velocimetry (PIV) to measure time resolved strain fields associated with the horizontal motion of a plate started from rest. PIV experiments show that the maxima in FD for ϕ>ϕc are associated with maxima in the spatially averaged shear strain field. For ϕ>ϕc the shear strain occurs in a narrow region in front of the plate, a shear band. For ϕϕc, surface particles move only during the formation of the shear band, coincident with the maxima in FD, after which the particles remain immobile until the sheared region reaches the measurement region.

  14. Media Education as a Vehicle for Teaching Religion: A Hong Kong Case

    Science.gov (United States)

    Cheung, Chi-Kim

    2006-01-01

    In this age of advanced technology, the pervasive influences of the media on pupils has aroused widespread concern among educators in general and religious educators in particular. This article argues for the teaching of religion through media education. It first discusses the interest of religious groups in media education and how media education…

  15. Teaching, Learning, and Sharing: How Today's Higher Education Faculty Use Social Media

    Science.gov (United States)

    Moran, Mike; Seaman, Jeff; Tinti-Kane, Hester

    2011-01-01

    Faculty are big users of and believers in social media. Virtually all higher education teaching faculty are aware of the major social media sites; more than three-quarters visited a social media site within the past month for their personal use; and nearly one-half posted content. Even more impressive is their rate of adoption of social media in…

  16. Mechanical Behavior of Granular/Particulate Media Reinforced with Fibers

    National Research Council Canada - National Science Library

    Michalowski, Radoslw

    1999-01-01

    ... out. This investigation was built on the results of a previous study. Fiber-reinforced granular material was considered as a composite, and a mathematical homogenization scheme was used to arrive at its macroscopic properties...

  17. Social Media and Social Networking Applications for Teaching and Learning

    Science.gov (United States)

    Yeo, Michelle Mei Ling

    2014-01-01

    This paper aims to better understand the experiences of the youth and the educators with the tapping of social media like YouTube videos and the social networking application of Facebook for teaching and learning. This paper is interested in appropriating the benefits of leveraging of social media and networking applications like YouTube and…

  18. Using Videos To Teach Mass Media and Society from a Critical Perspective.

    Science.gov (United States)

    King, Donna Lee

    2000-01-01

    Explores using videos to teach mass media and society from a critical sociological perspective. Discusses the content of the course from focusing on analysis of corporate capitalism and media producers to analyzing popular media texts on gender, race, the working class, and sexuality. Addresses the evaluation of the course. (CMK)

  19. Using social media technologies for teaching and research

    OpenAIRE

    Minocha, Shailey

    2012-01-01

    The goal of this workshop is to examine and discuss how educators and researchers can adopt and use social media tools such as blogs, wikis, micro-blogging (e.g. Twitter), social bookmarking tools, photo-sharing sites (e.g. Flickr), or social networking tools (e.g. Facebook) in the service of their teaching and research, and, particularly, in engaging with students and other researchers. \\ud \\ud We will cover the following topics in the workshop:\\ud a. A catalogue of social media tools that c...

  20. Have Economic Educators Embraced Social Media as a Teaching Tool?

    Science.gov (United States)

    Al-Bahrani, Abdullah; Patel, Darshak; Sheridan, Brandon J.

    2017-01-01

    In this article, the authors discuss the results of a study of the perceptions of a national sample of economics faculty members from various institutions regarding the use of social media as a teaching tool in and out of the economics classroom. In the past few years, social media has become globally popular, and its use is ubiquitous among…

  1. Effect of granular porous media on the composting of swine manure

    International Nuclear Information System (INIS)

    Kim, Ku-Yong; Kim, Hyun-Woo; Han, Sun-Kee; Hwang, Eung-Ju; Lee, Chae-Young; Shin, Hang-Sik

    2008-01-01

    This study investigated the feasibility of a bulking agent of granular porous media (GPM) for the composting of swine manure. Two lab-scale composting reactors were operated to evaluate the general performances and maturity parameters using GPM made of wastes from the Portland cement manufacturing processes as an alternative bulking agent. The overall volatile solid (VS) removal was 38.5% (dry basis). During the experiments, moisture content ranged between 41% and 53%, ensuring feasibility of microbial activity in composting. Cured compost showed proper maturity and low phytotoxicity, despite the slight decreases of CO 2 production and VS removal at the second batch operation. Various physico-chemical parameters of the cured compost met the regulatory standards reported elsewhere. The pH, carbon-to-nitrogen ratio, ammonia nitrogen and soluble organic carbon (SOC) of the cured compost were significantly correlated to the germination index (GI) using the seeds of Chinese cabbage and lettuce, indicating the progressive biodegradation of phytotoxins as well as organic matter. Consequently, the results obtained in this study demonstrate that GPM could contribute to the environmentally friendly and economical composting of problematic swine manure as a recyclable bulking agent

  2. Effect of granular porous media on the composting of swine manure.

    Science.gov (United States)

    Kim, Ku-Yong; Kim, Hyun-Woo; Han, Sun-Kee; Hwang, Eung-Ju; Lee, Chae-Young; Shin, Hang-Sik

    2008-11-01

    This study investigated the feasibility of a bulking agent of granular porous media (GPM) for the composting of swine manure. Two lab-scale composting reactors were operated to evaluate the general performances and maturity parameters using GPM made of wastes from the Portland cement manufacturing processes as an alternative bulking agent. The overall volatile solid (VS) removal was 38.5% (dry basis). During the experiments, moisture content ranged between 41% and 53%, ensuring feasibility of microbial activity in composting. Cured compost showed proper maturity and low phytotoxicity, despite the slight decreases of CO2 production and VS removal at the second batch operation. Various physico-chemical parameters of the cured compost met the regulatory standards reported elsewhere. The pH, carbon-to-nitrogen ratio, ammonia nitrogen and soluble organic carbon (SOC) of the cured compost were significantly correlated to the germination index (GI) using the seeds of Chinese cabbage and lettuce, indicating the progressive biodegradation of phytotoxins as well as organic matter. Consequently, the results obtained in this study demonstrate that GPM could contribute to the environmentally friendly and economical composting of problematic swine manure as a recyclable bulking agent.

  3. Analytical and Computational Modeling of Mechanical Waves in Microscale Granular Crystals: Nonlinearity and Rotational Dynamics

    Science.gov (United States)

    Wallen, Samuel P.

    Granular media are one of the most common, yet least understood forms of matter on earth. The difficulties in understanding the physics of granular media stem from the fact that they are typically heterogeneous and highly disordered, and the grains interact via nonlinear contact forces. Historically, one approach to reducing these complexities and gaining new insight has been the study of granular crystals, which are ordered arrays of similarly-shaped particles (typically spheres) in Hertzian contact. Using this setting, past works explored the rich nonlinear dynamics stemming from contact forces, and proposed avenues where such granular crystals could form designer, dynamically responsive materials, which yield beneficial functionality in dynamic regimes. In recent years, the combination of self-assembly fabrication methods and laser ultrasonic experimental characterization have enabled the study of granular crystals at microscale. While our intuition may suggest that these microscale granular crystals are simply scaled-down versions of their macroscale counterparts, in fact, the relevant physics change drastically; for example, short-range adhesive forces between particles, which are negligible at macroscale, are several orders of magnitude stronger than gravity at microscale. In this thesis, we present recent advances in analytical and computational modeling of microscale granular crystals, in particular concerning the interplay of nonlinearity, shear interactions, and particle rotations, which have previously been either absent, or included separately at macroscale. Drawing inspiration from past works on phononic crystals and nonlinear lattices, we explore problems involving locally-resonant metamaterials, nonlinear localized modes, amplitude-dependent energy partition, and other rich dynamical phenomena. This work enhances our understanding of microscale granular media, which may find applicability in fields such as ultrasonic wave tailoring, signal processing

  4. Status of Utilizing Social Media Networks in the Teaching-Learning Process at Public Jordanian Universities

    Directory of Open Access Journals (Sweden)

    Muneera Abdalkareem Alshdefait

    2018-03-01

    Full Text Available This study aimed at finding out the status of utilizing social media networks in the teaching-learning process at public Jordanian Universities. To achieve the goal of the study, the descriptive developmental method was used and a questionnaire was developed, consisting of (35 statements. The questionnaire was checked for its validity and reliability. Then it was distributed to a sample of (382 male and female students from the undergraduate and graduate levels. The study results showed that the participants gave a low score to the status of utilizing social media networks in the teaching-learning process at public Jordanian universities. The results also showed that there were statistically significant differences between the participants of the study according to the academic rank attributed to the graduate students, and according to gender attributed to male students at the instrument macro level and on all dimensions of the two variables. In light of these results, the study recommended that public universities should utilize modern technology in the educational process, urge and encourage the teaching staff members to use the social media networks in the teaching-learning process and raise the students' awareness about the benefits of using social media networks. Keywords: Social media networks, Teaching-learning process, Public Jordanian Universities

  5. Teaching Electronic Literacy A Concepts-Based Approach for School Library Media Specialists

    CERN Document Server

    Craver, Kathleen W

    1997-01-01

    School library media specialists will find this concepts-based approach to teaching electronic literacy an indispensable basic tool for instructing students and teachers. It provides step-by-step instruction on how to find and evaluate needed information from electronic databases and the Internet, how to formulate successful electronic search strategies and retrieve relevant results, and how to interpret and critically analyze search results. The chapters contain a suggested lesson plan and sample assignments for the school library media specialist to use in teaching electronic literacy skills

  6. Teaching perceptual skills in clinical diagnostics using digital media

    NARCIS (Netherlands)

    Scheiter, Katharina; Jarodzka, Halszka

    2011-01-01

    Scheiter, K., & Jarodzka, H. (2011, May). Teaching perceptual skills in clinical diagnostics using digital media. Presentation at the 2nd International Conference “Research in Medical Education”: Shaping diamonds from bench to bedside, Universität Tübingen.

  7. Teaching Media and Methods in Marketing: European and North American Universities

    Science.gov (United States)

    Vila, Natalia; Kuster, Ines

    2009-01-01

    This article aims to examine the most widely used teaching media and methods in university education. To achieve this objective, international research has been carried out among 135 marketing teachers from North American and European universities. The study shows that North American teachers use more traditional media and participatory methods…

  8. The behaviour of free-flowing granular intruders

    Directory of Open Access Journals (Sweden)

    Wyburn Edward

    2017-01-01

    Full Text Available Particle shape affects both the quasi-static and dynamic behaviour of granular media. There has been significant research devoted to the flowability of systems of irregularly shaped particles, as well as the flow of grains around fixed intruders, however the behaviour of free flowing intruders within granular flows remains comparatively unexplored. Here, the effect of the shape of these intruder particles is studied, looking at the kinematic behaviour of the intruders and in particular their tendency of orientation. Experiments are carried out within the Stadium Shear Device, which is a novel apparatus able to continuously apply simple shear conditions to two-dimensional grain analogues. It is found that the intruder shows different behaviour to that of the bulk flow, and that this behaviour is strongly shape dependent. These insights could lead to the development of admixtures that alter the flowability of granular materials.

  9. TEACHING VOCABULARY BY USING REALIA (REAL-OBJECT MEDIA

    Directory of Open Access Journals (Sweden)

    Dodi Irawan

    2017-03-01

    Full Text Available English is one of scary subject for some students of Indonesia. The students feel afraid to speak in English because of their less word of vocabulary. Realia media is the one simple interesting media that may bring motivation for the student who afraid to study English. Teacher of English can use realia media and bring it in the class to get more attention, and participation of students. In this research, the writer try to focuses on how realia media make significant difference ability of vocabulary to the students. The reserach of this study used a quasi-experimental method the population of this research was taken from the seventh grade Students of SMP Negeri 23 Palembang in the academic of year 2015/2016. Based on the research, it found that there was a significance difference using Realia media in teaching vocabulary. From the result on this research, it was found that there is a significant difference in achievement before and after the treatment in experimental group.

  10. Factors influence the digital media teaching of primary school ...

    African Journals Online (AJOL)

    EAOSA

    Keywords: digital media; flipped classroom; learning achievement; teaching ... Despite the negative high start-up cost, Touchton (2015) has argued that ... results in the cognition, affection and skills and so on”. ... teachers have ignored the importance of establish- .... Guided by engagement researches and theories, this.

  11. Controlling wave propagation through nonlinear engineered granular systems

    Science.gov (United States)

    Leonard, Andrea

    We study the fundamental dynamic behavior of a special class of ordered granular systems in order to design new, structured materials with unique physical properties. The dynamic properties of granular systems are dictated by the nonlinear, Hertzian, potential in compression and zero tensile strength resulting from the discrete material structure. Engineering the underlying particle arrangement of granular systems allows for unique dynamic properties, not observed in natural, disordered granular media. While extensive studies on 1D granular crystals have suggested their usefulness for a variety of engineering applications, considerably less attention has been given to higher-dimensional systems. The extension of these studies in higher dimensions could enable the discovery of richer physical phenomena not possible in 1D, such as spatial redirection and anisotropic energy trapping. We present experiments, numerical simulation (based on a discrete particle model), and in some cases theoretical predictions for several engineered granular systems, studying the effects of particle arrangement on the highly nonlinear transient wave propagation to develop means for controlling the wave propagation pathways. The first component of this thesis studies the stress wave propagation resulting from a localized impulsive loading for three different 2D particle lattice structures: square, centered square, and hexagonal granular crystals. By varying the lattice structure, we observe a wide range of properties for the propagating stress waves: quasi-1D solitary wave propagation, fully 2D wave propagation with tunable wave front shapes, and 2D pulsed wave propagation. Additionally the effects of weak disorder, inevitably present in real granular systems, are investigated. The second half of this thesis studies the solitary wave propagation through 2D and 3D ordered networks of granular chains, reducing the effective density compared to granular crystals by selectively placing wave

  12. Bubbling in vibrated granular films.

    Science.gov (United States)

    Zamankhan, Piroz

    2011-02-01

    With the help of experiments, computer simulations, and a theoretical investigation, a general model is developed of the flow dynamics of dense granular media immersed in air in an intermediate regime where both collisional and frictional interactions may affect the flow behavior. The model is tested using the example of a system in which bubbles and solid structures are produced in granular films shaken vertically. Both experiments and large-scale, three-dimensional simulations of this system are performed. The experimental results are compared with the results of the simulation to verify the validity of the model. The data indicate evidence of formation of bubbles when peak acceleration relative to gravity exceeds a critical value Γ(b). The air-grain interfaces of bubblelike structures are found to exhibit fractal structure with dimension D=1.7±0.05.

  13. Role of contact couples and couple stress in the behaviour of granular media

    International Nuclear Information System (INIS)

    Dedecker, F.; Dubujet, P.; Cambou, B.

    1998-01-01

    This paper analyses the interest of taking into account contact couples in the granular material description as well as considering the inadequacy of the micropolar description. The study is made on two types of samples: one which takes into account contact couples, and the other which does not. The response of these two media, which are submitted to a biaxial test, is analysed from both the micromechanic and macroscopic viewpoints. A numerical study which is performed on these two samples shows the influence of the presence of couples on the local static variables as well as on the macroscopic behaviour. A statistical homogenization approach is analysed to simulate the effects of couples. Due to the presence of an internal variable, a numerical study proves that this approach is relevant. This internal variable allows the taking into consideration of the influence of contact couples. A first step in the description of couples versus contact orientation is made by the introduction of the standard deviation. Finally, the inadequacy of the micropolar description which takes into account micropolar stresses is pointed out. (orig.)

  14. Using Media to Teach How Not to Do Psychotherapy

    Science.gov (United States)

    Gabbard, Glen; Horowitz, Mardi

    2010-01-01

    Objective: This article describes how using media depictions of psychotherapy may help in teaching psychiatric residents. Methods: Using the HBO series "In Treatment" as a model, the authors suggest how boundary transgressions and technical errors may inform residents about optimal psychotherapeutic approaches. Results: The psychotherapy vignettes…

  15. Real-time magnetic resonance imaging of highly dynamic granular phenomena

    Science.gov (United States)

    Penn, Alexander; Pruessmann, Klaas P.; Müller, Christoph

    Probing non-intrusively the interior of three-dimensional granular systems is a challenging task for which a number of imaging techniques have been applied including positron emission particle tracking, X-ray tomography and magnetic resonance imaging (MRI). A particular advantage of MRI is its versatility allowing quantitative velocimetry through phase contrast encoding and tagging, arbitrary slice orientations and the flexibility to trade spatial for temporal resolution and vice versa during image reconstruction. However, previous attempts to image granular systems using MRI were often limited to (pseudo-) steady state systems due to the poor temporal resolution of conventional imaging methodology. Here we present an experimental approach that overcomes previous limitations in temporal resolution by implementing a variety of methodological advances, viz. parallel data acquisition through tailored multiple receiver coils, fast gradient readouts for time-efficient data sampling and engineered granular materials that contain signal sources of high proton density. Achieving a spatial and temporal resolution of, respectively, 2 mm x 2 mm and 50 ms, we were able to image highly dynamic phenomena in granular media such as bubble coalescence and granular compaction waves.

  16. Teaching Journalistic Texts in Science Classes: the Importance of Media Literacy

    Science.gov (United States)

    Ginosar, Avshalom; Tal, Tali

    2017-11-01

    This study employs a single framework for investigating both environmental journalistic texts published on news websites, and science teachers' choices of such texts for their teaching. We analyzed 188 environmental items published during 2 months in seven news websites to determine popularity of topics. Then, 64 science junior high school teachers responded to a closed questionnaire to identify their preferred topics for using in the classroom and patterns of using environmental news items. In a second, open-ended questionnaire, responded by 50 teachers, we investigated the teachers' media literacy in terms of identifying text types and writers of environmental news items. Good alignment was found between the published topics on the websites and teachers' choices, with somewhat different distribution of topics, which could be explained by curriculum requirements. Teachers' identification of text types and writer types was inaccurate, which implied that their media literacy is inadequate. We argue that media literacy is required for effective use of journalistic texts in science teaching.

  17. Gas-solute dispersivity ratio in granular porous media as related to particle size distribution and particle shape

    DEFF Research Database (Denmark)

    Pugliese, Lorenzo; Poulsen, Tjalfe; Straface, Salvatore

    2013-01-01

    Measurements of solute dispersion in porous media is generally much more time consuming than gas dispersion measurements performed under equivalent conditions. Significant time savings may therefore, be achieved if solute dispersion coefficients can be estimated based on measured gas dispersion...... data. This paper evaluates the possibility for estimating solute dispersion based on gas dispersion measurements. Breakthrough measurements were carried out at different fluid velocities (covering the same range in Reynolds number), using O2 and NaCl as gas and solute tracers, respectively. Three...... different, granular porous materials were used: (1) crushed granite (very angular particles), (2) gravel (particles of intermediate roundness) and (3) Leca® (almost spherical particles). For each material, 21 different particle size fractions were used. Gas and solute dispersion coefficients were determined...

  18. Social Media Storytelling as a Method for Teaching Literature

    DEFF Research Database (Denmark)

    Pajares Tosca, Susana; Nørgaard Isholdt, Anne Katrine; Tarp-Petzke, Niklas

    2016-01-01

    This chapter investigates how a social medium (Facebook in this case) can be a platform for a novel way of teaching literature focusing on social roleplaying of the literary characters. We call this new form “social media storytelling”. Our project transmedially recreates the world of an original...

  19. Granular filtration for airborne particles : correlation between experiments and models

    Energy Technology Data Exchange (ETDEWEB)

    Golshahi, L.; Tan, Z. [Calgary Univ., AB (Canada). Schulich School of Engineering, Mechanical and Manufacturing Dept.; Abedi, J. [Calgary Univ., AB (Canada). Schulich School of Engineering, Chemical and Petroleum Engineering Dept.

    2009-10-15

    A new design for a packed bed granular filter was presented. The cylindrical packed bed was designed to filter particles in the range of approximately 10 nm to 15 {mu}m in diameter in different kinetic conditions and configurations. The aim of the study was to develop a precise empirical model to predict the filtration efficiency of the packed beds. A collision-type atomizer was used to generate polydisperse sodium chloride aerosol particles. The effect of flow rates was studied using a thermal mass flow meter. A regression analysis technique was used to determine the correlation between single granule and total packed bed efficiency for the entire granular filter. The experimental data were then compared with results obtained from the theoretical analysis. The least square method was used to correlate experimental data and to develop generalized equations for single granule efficiency. The study showed that the granular filter media has a high filtration efficiency for both micron and submicron particles. It was concluded that the effect of media thickness was more significant at higher flow rates than at lower flow rates. 10 refs., 3 figs.

  20. Social Teaching: Student Perspectives on the Inclusion of Social Media in Higher Education

    Science.gov (United States)

    Cooke, Samantha

    2017-01-01

    The traditional teaching methodologies employed within universities, comprising of lectures and seminars, have come to be scrutinised for their impersonal approach. Recently, social media and networking sites have become increasingly popular as learning and teaching resources in higher education, providing students with increased opportunities for…

  1. Numerical investigations on flow dynamics of prismatic granular materials using the discrete element method

    Science.gov (United States)

    Hancock, W.; Weatherley, D.; Wruck, B.; Chitombo, G. P.

    2012-04-01

    The flow dynamics of granular materials is of broad interest in both the geosciences (e.g. landslides, fault zone evolution, and brecchia pipe formation) and many engineering disciplines (e.g chemical engineering, food sciences, pharmaceuticals and materials science). At the interface between natural and human-induced granular media flow, current underground mass-mining methods are trending towards the induced failure and subsequent gravitational flow of large volumes of broken rock, a method known as cave mining. Cave mining relies upon the undercutting of a large ore body, inducement of fragmentation of the rock and subsequent extraction of ore from below, via hopper-like outlets. Design of such mines currently relies upon a simplified kinematic theory of granular flow in hoppers, known as the ellipsoid theory of mass movement. This theory assumes that the zone of moving material grows as an ellipsoid above the outlet of the silo. The boundary of the movement zone is a shear band and internal to the movement zone, the granular material is assumed to have a uniformly high bulk porosity compared with surrounding stagnant regions. There is however, increasing anecdotal evidence and field measurements suggesting this theory fails to capture the full complexity of granular material flow within cave mines. Given the practical challenges obstructing direct measurement of movement both in laboratory experiments and in-situ, the Discrete Element Method (DEM [1]) is a popular alternative to investigate granular media flow. Small-scale DEM studies (c.f. [3] and references therein) have confirmed that movement within DEM silo flow models matches that predicted by ellipsoid theory, at least for mono-disperse granular material freely outflowing at a constant rate. A major draw-back of these small-scale DEM studies is that the initial bulk porosity of the simulated granular material is significantly higher than that of broken, prismatic rock. In this investigation, more

  2. Wave propagation of spectral energy content in a granular chain

    NARCIS (Netherlands)

    Shrivastava, Rohit Kumar; Luding, Stefan

    2017-01-01

    A mechanical wave is propagation of vibration with transfer of energy and momentum. Understanding the spectral energy characteristics of a propagating wave through disordered granular media can assist in understanding the overall properties of wave propagation through inhomogeneous materials like

  3. Poroelastic measurement schemes resulting in complete data sets for granular and other anisotropic porous media

    Energy Technology Data Exchange (ETDEWEB)

    Berryman, J.G.

    2009-11-20

    Poroelastic analysis usually progresses from assumed knowledge of dry or drained porous media to the predicted behavior of fluid-saturated and undrained porous media. Unfortunately, the experimental situation is often incompatible with these assumptions, especially when field data (from hydrological or oil/gas reservoirs) are involved. The present work considers several different experimental scenarios typified by one in which a set of undrained poroelastic (stiffness) constants has been measured using either ultrasound or seismic wave analysis, while some or all of the dry or drained constants are normally unknown. Drained constants for such a poroelastic system can be deduced for isotropic systems from available data if a complete set of undrained compliance data for the principal stresses are available - together with a few other commonly measured quantities such as porosity, fluid bulk modulus, and grain bulk modulus. Similar results are also developed here for anisotropic systems having up to orthotropic symmetry if the system is granular (i.e., composed of solid grains assembled into a solid matrix, either by a cementation process or by applied stress) and the grains are known to be elastically homogeneous. Finally, the analysis is also fully developed for anisotropic systems with nonhomogeneous (more than one mineral type), but still isotropic, grains - as well as for uniform collections of anisotropic grains as long as their axes of symmetry are either perfectly aligned or perfectly random.

  4. Sprint's Social Media Ninja Program: A Model for Teaching Consumer Relations

    Science.gov (United States)

    Gilliland, Rebecca A.

    2017-01-01

    This study reviews the application of a new training model, Sprint's Social Media Ninja program, an innovative approach to using new media to initiate change. Sprint recognized change management must occur from employee ambassadors to relevant audiences including consumers and other employees. By teaching volunteer employees the strategic message…

  5. Granular flow

    DEFF Research Database (Denmark)

    Mitarai, Namiko; Nakanishi, Hiizu

    2012-01-01

    Granular material is a collection of macroscopic particles that are visible with naked eyes. The non-equilibrium nature of the granular materials makes their rheology quite different from that of molecular systems. In this minireview, we present the unique features of granular materials focusing...... on the shear flow of dry granular materials and granule-liquid mixture....

  6. Using Social Media Applications for Educational Outcomes in College Teaching: A Structural Equation Analysis

    Science.gov (United States)

    Cao, Yingxia; Ajjan, Haya; Hong, Paul

    2013-01-01

    As more and more faculty members jump on the wagon of social media, an increasing number of publications began to investigate the adoption of social media applications and its motivators in and out of the classrooms. However, little research has paid close attention to the educational outcomes of social media utilization in college teaching. Thus,…

  7. Using Social Media to Promote Pre-Service Science Teachers' Practices of Socio-Scientific Issue (SSI) - Based Teaching

    Science.gov (United States)

    Pitiporntapin, Sasithep; Lankford, Deanna Marie

    2015-01-01

    This paper addresses using social media to promote pre-service science teachers' practices of Socio-Scientific Issue (SSI) based teaching in a science classroom setting. We designed our research in two phases. The first phase examined pre-service science teachers' perceptions about using social media to promote their SSI-based teaching. The…

  8. Development of mixed microbial granular biofilms for denitrification of concentrated wastes

    International Nuclear Information System (INIS)

    Krishna Mohan, T.V.; Nancharaiah, Y.V.; Venugopalan, V.P.; Narasimhan, S.V.; Satyasai, P.M.

    2010-01-01

    Nitrate containing wastes are generated at various stages of the nuclear fuel cycle; fuel fabrication and reprocessing. A treatment process for removing nitrate from such concentrated nitrate bearing effluents is needed. Among other available options, biological denitrification is an economical and technically feasible method for nitrate removal. Granular biofilm based sequencing batch reactors (SBRs) may allow designing a compact and high rate processes suitable for the treatment of concentrated effluents. Hence, experiments were carried out in laboratory scale sequencing batch reactors (SBRs) to develop granular biofilms (composed of mixed microbes) for removing nitrate from the concentrated nitrate containing-media. Microbial granular biofilms, capable of consuming nitrate up to 2710 mg/l nitrate-N, were developed under anaerobic conditions in a 6-litre volume sequencing batch reactor (SBR). The SBR was inoculated with activated sludge flocs and operated with 24-h cycle and 50% volumetric exchange ratio. Synthetic media containing acetate as the energy source and electron donor, at carbon to nitrogen molar ratio of 2:1 and 3:1 was fed into the SBRs. Nitrate-N concentration in the SBR was increased in a step-wise manner starting from 677 to 2710 mg/l (1355 to 5420 mg/l in the feed). Complete removal of influent nitrate occurred within the first few hours of SBR cycle period. Effluent nitrate and nitrite levels (∼3 mg/l nitrate-N or nitrite-N) at the end of SBR cycle period (24 h) were found to be below the discharge limits. Under these conditions biomass predominantly consisted of granular biofilms. Results show the potential of granular biofilm based SBR for converting nitrate to nitrogen gas from concentrated nitrate bearing industrial effluents. (author)

  9. Capturing gas in soft granular media

    Science.gov (United States)

    MacMinn, Chris; Lee, Jeremy; Xu, Feng; Lee, Sungyon

    2017-11-01

    Bubble migration through soft granular materials involves a strong coupling between the bubble dynamics and the deformation of the material. This process is relevant to a variety of natural and industrial systems, from fluidized-bed reactors to the migration and venting of biogenic gas in sediments. Here, we study this process experimentally by injecting air into a quasi-2D, liquid-saturated packing of soft particles and measuring the morphology of the bubbles as they invade and then rise due to buoyancy. By systematically varying the confining stress, we show that the competition between buoyancy, capillarity, and elasticity leads to complex bubble-migration dynamics that transition from fluidization to pathway opening to pore invasion, with a strong and surprising impact on the amount of air trapped in the system. The authors are grateful for support from the Royal Society (IE150885), the John Fell Oxford University Press Research Fund, and the Maurice Lubbock Memorial Fund.

  10. Mechanical and Structural Behavior of Granular Material Packed Beds for Space Life Support System Applications

    Science.gov (United States)

    Malla, Ramesh B.; Anandakumar, Ganesh

    2005-01-01

    Long-term human mission to space, such as living in International Space Station (ISS), Lunar, and Martian bases, and travel to Mars, must m ake use of Advanced Life Support Systems (ALSS) to generate and recycle critical life supporting elements like oxygen and water. Oxygen Gen eration Assembly (OGA) and Water Processor Assembly (WPA), critical c omponents of ALSS, make use of series of granular material packed beds for generation and recycling of oxygen and water. Several granular m aterials can be used for generation, recycling, processing and recovery of oxygen and water. For example, they may include soft bed media, e.g. ion exchange resins for oxygen generation assembly and hard bed media such as, activated alumina, magchem (Magnesium oxide) and activa ted carbon to remove organic species like ethanol, methanol, and urea from wastewater in Water recovery/processing assembly. These beds are generally packed using a plate-spring mechanism to provide sufficien t compaction to the bed media throughout the course of operation. This paper presents results from an experimental study of a full-scale, 3 8.1 cm (15 inches) long and 3.7 cm (1.44 inches) diameter. activated alumina bed enclosed in a cylinder determining its force-displacement behavior, friction mobilizing force, and axial normal stress distribu tion under various axially applied loads and at different levels of packing. It is observed that force-displacement behavior is non-linear for low compaction level and becomes linear with increase in compaction of the bed media. Axial normal stress distribution along the length of the bed media decreased non-linearly with increase in depth from the loading end of the granular media. This paper also presents experimental results on the amount of particulates generated corresponding to various compaction levels. Particulates generated from each of the tests were measured using standard US sieves. It was found that the p articulates and the overall displacement of

  11. Relationship between electrical conductivity anisotropy and fabric anisotropy in granular materials during drained triaxial compressive tests: a numerical approach

    Science.gov (United States)

    Niu, Qifei; Revil, André; Li, Zhaofeng; Wang, Yu-Hsing

    2017-07-01

    The anisotropy of granular media and its evolution during shearing are important aspects required in developing physics-based constitutive models in Earth sciences. The development of relationships between geoelectrical properties and the deformation of porous media has applications to the monitoring of faulting and landslides. However, such relationships are still poorly understood. In this study, we first investigate the definition of the electrical conductivity anisotropy tensor of granular materials in presence of surface conductivity of the grains. Fabric anisotropy is related to the components of the fabric tensor. We define an electrical anisotropy factor based on the Archie's exponent second-order symmetric tensor m of granular materials. We use numerical simulations to confirm a relationship between the evolution of electrical and fabric anisotropy factors during shearing. To realize the simulations, we build a virtual laboratory in which we can easily perform synthetic experiments. We first simulate drained compressive triaxial tests of loose and dense granular materials (porosity 0.45 and 0.38, respectively) using the discrete element method. Then, the electrical conductivity tensor of a set of deformed synthetic samples is computed using the finite-difference method. The numerical results show that shear strains are responsible for a measurable anisotropy in the bulk conductivity of granular media. The observed electrical anisotropy response, during shearing, is distinct for dense and loose synthetic samples. Electrical and fabric anisotropy factors exhibit however a unique linear correlation, regardless of the shear strain and the initial state (porosity) of the synthetic samples. The practical implication of this finding confirms the usefulness of the electrical conductivity method in studying the fabric tensor of granular media. This result opens the door in using time-lapse electrical resistivity to study non-intrusively the evolution of anisotropy

  12. Going Public on Social Media

    Directory of Open Access Journals (Sweden)

    Greg Elmer

    2015-04-01

    Full Text Available This brief essay questions the disconnect between the financial goals of social media properties and the concerns of privacy advocates and other new media critics. It is argued that critics of social media often fail to recognize the financial imperative of social media companies, one that requires users to divulge and publicize ever more granular aspects of their daily lives, thoughts, and feelings.

  13. Linear and nonlinear Biot waves in a noncohesive granular medium slab: transfer function, self-action, second harmonic generation.

    Science.gov (United States)

    Legland, J-B; Tournat, V; Dazel, O; Novak, A; Gusev, V

    2012-06-01

    Experimental results are reported on second harmonic generation and self-action in a noncohesive granular medium supporting wave energy propagation both in the solid frame and in the saturating fluid. The acoustic transfer function of the probed granular slab can be separated into two main frequency regions: a low frequency region where the wave propagation is controlled by the solid skeleton elastic properties, and a higher frequency region where the behavior is dominantly due to the air saturating the beads. Experimental results agree well with a recently developed nonlinear Biot wave model applied to granular media. The linear transfer function, second harmonic generation, and self-action effect are studied as a function of bead diameter, compaction step, excitation amplitude, and frequency. This parametric study allows one to isolate different propagation regimes involving a range of described and interpreted linear and nonlinear processes that are encountered in granular media experiments. In particular, a theoretical interpretation is proposed for the observed strong self-action effect.

  14. Impact induced splash and spill in a quasi-confided granular medium

    Science.gov (United States)

    Ogale, S. B.

    2005-03-01

    Dissipation of the energy of impact in a granular medium and its effects has been a subject of considerable scientific for quite some time. In this work we have explored and analyzed the splash and spill effects caused by the impact of a ball dropped from a height into a granular medium in a open container. Three different granular media, namely rice, mustard seeds, and cream of wheat were used. The amount of spilled-over granular matter was measured as a function of the ball-drop height. Digital pictures of the splash process were also recorded. The quantity of spilled granular matter varies linearly with the impact energy. However additional step like structures are also noted. Specifically, a distinct and large jump is seen in the spilled quantity at a specific impact energy in the case of mustard seeds, which also exhibit obvious charging effects and repulsion. Although the parameters such as mass per grain and packing density for the case of mustard seeds are intermediate between those for rice and cream of wheat, the spill quantity for comparable impact energy is considerably higher. These data will be presented and discussed.

  15. Critical state flow rules for CFD simulations of wet granular flows

    NARCIS (Netherlands)

    Schwarze, R.; Gladkyy, A.; Luding, Stefan; E. Onate M. Bischoff, E. Ramm; P. Wriggers,

    2013-01-01

    First rheological investigation results of weakly wet granular media are presented. The materials have been examined experimentally and numerically in well- defined shear configurations in steady state, in the intermediate flow regime. For the experiments, a Searl-type ring shear cell with rotating

  16. Bonding Strength Effects in Hydro-Mechanical Coupling Transport in Granular Porous Media by Pore-Scale Modeling

    Directory of Open Access Journals (Sweden)

    Zhiqiang Chen

    2016-03-01

    Full Text Available The hydro-mechanical coupling transport process of sand production is numerically investigated with special attention paid to the bonding effect between sand grains. By coupling the lattice Boltzmann method (LBM and the discrete element method (DEM, we are able to capture particles movements and fluid flows simultaneously. In order to account for the bonding effects on sand production, a contact bond model is introduced into the LBM-DEM framework. Our simulations first examine the experimental observation of “initial sand production is evoked by localized failure” and then show that the bonding or cement plays an important role in sand production. Lower bonding strength will lead to more sand production than higher bonding strength. It is also found that the influence of flow rate on sand production depends on the bonding strength in cemented granular media, and for low bonding strength sample, the higher the flow rate is, the more severe the erosion found in localized failure zone becomes.

  17. Influence of granulometry in the Hurst exponent of air liquid interfaces formed during capillary rising in a granular media

    Directory of Open Access Journals (Sweden)

    Gontijo Guilherme L.

    2017-01-01

    Full Text Available We report results concerning the fractal dimension of a air/fluid interface formed during the capillary rising of a fluid into a dense granular media. The system consists in a modified Hele-Shaw cell filled with grains at different granulometries and confined in a narrow gap between the glass plates. The system is then placed onto a water reservoir, and the liquid penetrates the medium due to capillary forces. We measure the Hurst exponent of the liquid/air interface with help of image processing, and follow the temporal evolution of the profiles. We observe that the Hurst exponent can be related with the granulometry, but the range of values are odd to the predicted values from models or theory.

  18. Experimental investigation of the Rowe's dilatancy law on an atypical granular medium from a municipal solid waste incineration bottom ash

    Science.gov (United States)

    Becquart, Frédéric; Abriak, Nor Edine

    2013-06-01

    Municipal Solid Waste Incineration (MSWI) bottom ashes are irregular granular media because of their origin and are very heterogeneous with a large quantity of angular particles of different chemical species. MSWI bottom ash is a renewable granular resource alternative to the use of non-renewable standard granular materials. Beneficial use of these alternative granular materials mainly lies in road engineering. However, the studies about mechanical properties of such granular media still remain little developed, those being mainly based on empirical considerations. In this paper, a study of mechanical behaviour of a MSWI bottom ash under axisymmetric triaxial loadings conditions is presented. Samples are initially dense after Proctor compaction, are saturated and tested in drained conditions, under different effective confining pressures ranging from 100 to 600 kPa. The evolutions of volumetric strains show an initial contracting phase followed by a dilatancy phase, more pronounced when the confining pressure is low. The stresses ratios at the characteristic state and at the critical state appear in good agreement and with a null rate of volume variation. The angles of internal friction and dilatancy of the studied MSWI bottom ash are estimated and are similar to conventional granular materials used especially in road engineering. The dilatancy law of Rowe is well experimentally verified on this irregular recycled granular material.

  19. Granular media in the context of small bodies

    Science.gov (United States)

    Tancredi, G.

    2014-07-01

    Granular materials of different particle sizes are present on the surface and the interior of several atmosphereless Solar System bodies. The presence of very fine particles on the surface of the Moon, the so-called regolith, was confirmed by the Apollo astronauts. From the polarimetric observations and phase angle curves, it is possible to indirectly infer the presence of fine particles on the surfaces of asteroids and planetary satellites. More recently, the visit of spacecraft to several asteroids and comets has provided us with close pictures of the surface, where particles of a wide size range from cm to hundreds of meters have been directly observed. The presence of even finer particles on the visited bodies can also be inferred from image analysis. Solar System bodies smaller than a few hundred km may have a variety of internal structures: monolithic single bodies, objects with internal fractures, rubble piles maintained as a single object by self-gravity, etc. After the visit of the small asteroid Itokawa, it has been speculated that ''some small asteroids appear to be clumps of gravel glued by a very weak gravity field'' (Asphaug 2007). We still do not know the internal structure of these rubble piles and the size distribution of the interior constituents, but these clumps could have several million meter-sized boulders inside. There are several pieces of evidence that many asteroids are agglomerates of small components, like: - Rotation periods for small asteroids - Tidal disruption of asteroids and comets when they enter the Roche's limit of a massive object - The existence of crater chains like the ones observed in Ganymede - Low density estimates (laboratory experiments on granular material trying to reproduce the conditions in space: vacuum and low gravity. We describe the experimental set-ups and some results of these experiments. Some open problems and future line of work in this field will be presented.

  20. SOME ASPECTS OF TEACHING MEDIA LITERACY TO PRE-SCHOOL CHILDREN IN SLOVENIA FROM A PERCEPTION STANDPOINT OF TEACHERS AND PARENTS

    Directory of Open Access Journals (Sweden)

    Jurka Lepičnik Vodopivec

    2011-11-01

    Full Text Available This paper deals with media literacy as a multidimensional skill that parents and teachers possess. In this context we warn of the media-technical aspect of this skill and, within this aspect, of parents’ and teachers’ opinion on the presence of media in children’s lives. Following that, the paper explores teachers’ media-didactic competence as a component of educators’ media literacy. In the empiric part we used two aspects of fostering media literacy. One is the media-technical competence of parents and educators, while the other is the media-didactic competence of educators. We found that both parents and teachers believe that media have a strong presence in everyday lives of pre-school children and that they play an important role in teaching pre-school children. Teachers are aware of the importance of early teaching with media, for media and about media with the purpose of developing children’s media literacy, so they will not be afraid of media when they grow up.

  1. The Development of Teaching and Learning Innovation by Using Instructional Media for Enhancement of Learning Achievement towards Tourism Product Knowledge in Tourism Marketing Class

    Directory of Open Access Journals (Sweden)

    Somnuek Pariwat

    2014-01-01

    Full Text Available This study aimed to investigate (1 analyzed perspectives of the traditional teaching and the instructional media teaching to improve the tourism product knowledge in the tourism marketing class, (2 satisfaction levels, among second-year students majoring in tourism program, towards the instructional media teaching, and (3 comparative learning achievement of the students in the class. Survey questionnaires, pretest and post-test, and instructional media were applied for data collection. Furthermore, descriptive analysis and statistics such as Average, Standard Deviation, and Paired T-Test were employed of data analysis. The findings revealed that the traditional teaching employed lesser time and it was uncomplicated when applying for a class with a large number of students and several knowledge sources. However, the students played unimportant role and felt uninterested towards the lesson if the teachers were unskillful. The traditional teaching could not meet the needs and individual differences of the students while the instructional media could better develop their learning quality and their participation in learning and cognitive processes. The students’ satisfaction towards the instructional media teaching was presented in the high level. Additionally, the students learning with instructional media performed the higher average test points than those learning with the traditional teaching.

  2. Social Networking Media: An Approach for the Teaching of International Business

    Science.gov (United States)

    Barczyk, Casimir C.; Duncan, Doris G.

    2012-01-01

    Internet technology and Web 2.0 applications have enabled social networking media to expand in ways that link people globally. By fostering communication, social networks hold immense potential for the enhancement of teaching, especially in the business arena. This article defines social networking and provides a framework for understanding the…

  3. Attitudes of Health Professional Educators Toward the Use of Social Media as a Teaching Tool: Global Cross-Sectional Study

    Science.gov (United States)

    Henningham, Lucy; Zou, Runyu; Huang, Jessica; O'Sullivan, Elizabeth; Last, Jason; Ho, Kendall

    2017-01-01

    Background The use of social media in health education has witnessed a revolution within the past decade. Students have already adopted social media informally to share information and supplement their lecture-based learning. Although studies show comparable efficacy and improved engagement when social media is used as a teaching tool, broad-based adoption has been slow and the data on barriers to uptake have not been well documented. Objective The objective of this study was to assess attitudes of health educators toward social media use in education, examine differences between faculty members who do and do not use social media in teaching practice, and determine contributing factors for an increase in the uptake of social media. Methods A cross-sectional Web-based survey was disseminated to the faculty of health professional education departments at 8 global institutions. Respondents were categorized based on the frequency of social media use in teaching as “users” and “nonusers.” Users sometimes, often, or always used social media, whereas nonusers never or rarely used social media. Results A total of 270 health educators (52.9%, n=143 users and 47.0%, n=127 nonusers) were included in the survey. Users and nonusers demonstrated significant differences on perceived barriers and potential benefits to the use of social media. Users were more motivated by learner satisfaction and deterred by lack of technology compatibility, whereas nonusers reported the need for departmental and skill development support. Both shared concerns of professionalism and lack of evidence showing enhanced learning. Conclusions The majority of educators are open-minded to incorporating social media into their teaching practice. However, both users and nonusers have unique perceived challenges and needs, and engaging them to adapt social media into their educational practice will require previously unreported approaches. Identification of these differences and areas of overlap

  4. Attitudes of Health Professional Educators Toward the Use of Social Media as a Teaching Tool: Global Cross-Sectional Study.

    Science.gov (United States)

    D'Souza, Karan; Henningham, Lucy; Zou, Runyu; Huang, Jessica; O'Sullivan, Elizabeth; Last, Jason; Ho, Kendall

    2017-08-04

    The use of social media in health education has witnessed a revolution within the past decade. Students have already adopted social media informally to share information and supplement their lecture-based learning. Although studies show comparable efficacy and improved engagement when social media is used as a teaching tool, broad-based adoption has been slow and the data on barriers to uptake have not been well documented. The objective of this study was to assess attitudes of health educators toward social media use in education, examine differences between faculty members who do and do not use social media in teaching practice, and determine contributing factors for an increase in the uptake of social media. A cross-sectional Web-based survey was disseminated to the faculty of health professional education departments at 8 global institutions. Respondents were categorized based on the frequency of social media use in teaching as "users" and "nonusers." Users sometimes, often, or always used social media, whereas nonusers never or rarely used social media. A total of 270 health educators (52.9%, n=143 users and 47.0%, n=127 nonusers) were included in the survey. Users and nonusers demonstrated significant differences on perceived barriers and potential benefits to the use of social media. Users were more motivated by learner satisfaction and deterred by lack of technology compatibility, whereas nonusers reported the need for departmental and skill development support. Both shared concerns of professionalism and lack of evidence showing enhanced learning. The majority of educators are open-minded to incorporating social media into their teaching practice. However, both users and nonusers have unique perceived challenges and needs, and engaging them to adapt social media into their educational practice will require previously unreported approaches. Identification of these differences and areas of overlap presents opportunities to determine a strategy to increase

  5. Experimental Study of the Composition and Structure of Granular Media in the Shear Bands Based on the HHC-Granular Model

    Directory of Open Access Journals (Sweden)

    Guang-jin Wang

    2014-01-01

    Full Text Available The researchers cannot control the composition and structure of coarse grained soil in the indoor experiment because the granular particles of different size have the characteristics of random distribution and no sorting. Therefore, on the basis of the laboratory tests with the coarse grained soil, the HHC-Granular model, which could simulate the no sorting and random distribution of different size particles in the coarse-grained soil, was developed by use of cellular automata method. Meanwhile, the triaxial numerical simulation experiments of coarse grained soil were finished with the different composition and structure soil, and the variation of shear strength was discussed. The results showed that the internal friction angle was likely to reduce with the increasing of gravel contents in the coarse-grained soil, but the mean internal friction angle significantly increased with the increment of gravel contents. It indicated that the gravel contents of shear bands were the major factor affecting the shear strength.

  6. Developing Teaching Materials Using Comic Media to Enhance Students’ Mathematical Communication

    Science.gov (United States)

    Yulian, V. N.

    2018-04-01

    Teaching materials are a set of materials that are arranged systematically written or not, to create an environment or atmosphere that allows students to learn. The purpose of this study is to provide an overview of how the development of teaching materials using comic media that enhance mathematical communication, as well as feasible and effective teaching materials developed. Research method used in this research is Research and Development. In the sense of research contains about how to develop teaching materials through several stages such as validation by experts, as well as revisions. Sources of data used in this study were students and teachers SMK Bandung Barat. The results showed that the teaching materials developed feasible and effective use for students of class X SMK Bandung Barat. Teaching materials received a proper assessment of the experts after going through several stages of revision, in addition to the effective teaching materials used by students seen from the liveliness and the value of classical completeness that reaches more 85% of students. Based on the result of the research, it can be concluded that the developed teaching material gets the proper judgment from the expert, and effectively used in the learning by the students of X-1 Pharmacy class with the classical completeness reach 86% and the student activity is 91,4%.

  7. Wave propagation of spectral energy content in a granular chain

    Directory of Open Access Journals (Sweden)

    Shrivastava Rohit Kumar

    2017-01-01

    Full Text Available A mechanical wave is propagation of vibration with transfer of energy and momentum. Understanding the spectral energy characteristics of a propagating wave through disordered granular media can assist in understanding the overall properties of wave propagation through inhomogeneous materials like soil. The study of these properties is aimed at modeling wave propagation for oil, mineral or gas exploration (seismic prospecting or non-destructive testing of the internal structure of solids. The focus is on the total energy content of a pulse propagating through an idealized one-dimensional discrete particle system like a mass disordered granular chain, which allows understanding the energy attenuation due to disorder since it isolates the longitudinal P-wave from shear or rotational modes. It is observed from the signal that stronger disorder leads to faster attenuation of the signal. An ordered granular chain exhibits ballistic propagation of energy whereas, a disordered granular chain exhibits more diffusive like propagation, which eventually becomes localized at long time periods. For obtaining mean-field macroscopic/continuum properties, ensemble averaging has been used, however, such an ensemble averaged spectral energy response does not resolve multiple scattering, leading to loss of information, indicating the need for a different framework for micro-macro averaging.

  8. Using a Time Granularity Table for Gradual Granular Data Aggregation

    DEFF Research Database (Denmark)

    Iftikhar, Nadeem; Pedersen, Torben Bach

    2010-01-01

    solution for data reduction based on gradual granular data aggregation. With the gradual granular data aggregation mechanism, older data can be made coarse-grained while keeping the newest data fine-grained. For instance, when data is 3 months old aggregate to 1 minute level from 1 second level, when data...... and improve query performance, especially on resource-constrained systems with limited storage and query processing capabilities. A number of data reduction solutions have been developed, however an effective solution particularly based on gradual data reduction is missing. This paper presents an effective...... is 6 months old aggregate to 2 minutes level from 1 minute level and so on. The proposed solution introduces a time granularity based data structure, namely a relational time granularity table that enables long term storage of old data by maintaining it at different levels of granularity and effective...

  9. What Do Preservice Teachers Think about Teaching Media Literacy? An Exploratory Study Using the Theory of Planned Behavior

    Science.gov (United States)

    Gretter, Sarah; Yadav, Aman

    2018-01-01

    Despite the numerous benefits of media & information literacy for students in today's digital society, the lack of teacher preparation in teaching media and information literacy skills suggests a gap between the societal rationale for students becoming media literate and the sustainable preparation of teachers. The purpose of this exploratory…

  10. Portrait of a "Teach for All" (TFA) Teacher: Media Narratives of the Universal TFA Teacher in 12 Countries

    Science.gov (United States)

    Gautreaux, Michelle; Delgado, Sandra

    2016-01-01

    This article employs narrative analysis to examine how the media in 12 different countries characterize the "Teach for All" (TFA) teacher. Examining mass media narratives in these 12 countries illustrates that there are some remarkable commonalities in the narratives and character portraits co-constructed and propagated by the media. At…

  11. Coupled granular/continuous medium for thermally stable perpendicular magnetic recording

    International Nuclear Information System (INIS)

    Sonobe, Y.; Weller, D.; Ikeda, Y.; Takano, K.; Schabes, M.E.; Zeltzer, G.; Do, H.; Yen, B.K.; Best, M.E.

    2001-01-01

    We studied coupled granular/continuous (CGC) perpendicular media consisting of a continuous multilayer structure and a granular layer. The addition of Co/Pt multilayers decreased the nucleation field from 200 to -1800 Oe and increased the squareness from 0.9 to 1.0. The moment decay at room temperature was significantly reduced from -4.8% to -0.05% per decade. At elevated temperatures, strong exchange coupling between a granular layer and a continuous layer is needed for thermal stability. The exchange-coupled continuous layer reduces thermal demagnetization as it effectively increases the grain size, tightens the grain distribution, and prevents the reversal of individual grains. Magnetic Force Microscope image showed a larger magnetic cluster size for the CGC structure. Compared to the CoCr 18 Pt 12 medium, the CGC medium had 2.3 dB higher output. However, the noise for the CGC medium increased with the recording density, while the noise for the CoCr 18 Pt 12 medium remained constant from 4 to 15 kfc/mm. Further optimization and noise reduction are still required for future high density recording

  12. Coupled granular/continuous medium for thermally stable perpendicular magnetic recording

    Science.gov (United States)

    Sonobe, Y.; Weller, D.; Ikeda, Y.; Takano, K.; Schabes, M. E.; Zeltzer, G.; Do, H.; Yen, B. K.; Best, M. E.

    2001-10-01

    We studied coupled granular/continuous (CGC) perpendicular media consisting of a continuous multilayer structure and a granular layer. The addition of Co/Pt multilayers decreased the nucleation field from 200 to -1800 Oe and increased the squareness from 0.9 to 1.0. The moment decay at room temperature was significantly reduced from -4.8% to -0.05% per decade. At elevated temperatures, strong exchange coupling between a granular layer and a continuous layer is needed for thermal stability. The exchange-coupled continuous layer reduces thermal demagnetization as it effectively increases the grain size, tightens the grain distribution, and prevents the reversal of individual grains. Magnetic Force Microscope image showed a larger magnetic cluster size for the CGC structure. Compared to the CoCr 18Pt 12 medium, the CGC medium had 2.3 dB higher output. However, the noise for the CGC medium increased with the recording density, while the noise for the CoCr 18Pt 12 medium remained constant from 4 to 15 kfc/mm. Further optimization and noise reduction are still required for future high density recording.

  13. Developing a Magnetic Resonance Imaging measurement of the forces within 3D granular materials under external loads

    Science.gov (United States)

    Elrington, Stefan; Bertrand, Thibault; Frey, Merideth; Shattuck, Mark; O'Hern, Corey; Barrett, Sean

    2014-03-01

    Granular materials are comprised of an ensemble of discrete macroscopic grains that interact with each other via highly dissipative forces. These materials are ubiquitous in our everyday life ranging in scale from the granular media that forms the Earth's crust to that used in agricultural and pharmaceutical industries. Granular materials exhibit complex behaviors that are poorly understood and cannot be easily described by statistical mechanics. Under external loads individual grains are jammed into place by a network of force chains. These networks have been imaged in quasi two-dimensional and on the outer surface of three-dimensional granular materials. Our goal is to use magnetic resonance imaging (MRI) to detect contact forces deep within three-dimensional granular materials, using hydrogen-1 relaxation times as a reporter for changes in local stress and strain. To this end, we use a novel pulse sequence to narrow the line width of hydrogen-1 in rubber. Here we present our progress to date, and prospects for future improvements.

  14. Using Entertainment Media to Inform Student Affairs Teaching and Practice Related to Sex and Gender

    Science.gov (United States)

    Davis, Tracy L.

    2004-01-01

    This chapter presents several strategies for teaching about sex and gender using entertainment media and explores critical issues related to content development, the delivery process, and evaluation methods.

  15. May It Please the Court: Two Legal Cases to Teach Students about Social Media Based Terminations of Employment

    Science.gov (United States)

    O'Connor, Kimberly W.; Schmidt, Gordon B.

    2015-01-01

    Recent data suggest that 83% of individuals, aged 18 to 29 years, frequent social media sites (Drouin et al., 2015). This statistic confirms the need for universities to teach important issues regarding personal social media usage to students. At the forefront of these issues is how personal social media usage can affect students' future…

  16. Granular patterns

    CERN Document Server

    Aranson, Igor S

    2009-01-01

    This title presents a review of experiments and novel theoretical concepts needed to understand the mechanisms of pattern formation in granular materials. An effort is made to connect concepts and ideas developed in granular physics with new emergent fields, especially in biology, such as cytoskeleton dynamics.

  17. Disrupting Islamophobia: Teaching the Social Construction of Terrorism in the Mass Media

    Science.gov (United States)

    McQueeney, Krista

    2014-01-01

    This article presents a critical media literacy technique for teaching about the social construction of terrorism. In a post-9/11 context where the human rights of Arabs and Muslims in the United States and overseas are threatened by drone attacks, profiling, detentions, and hate crimes, educators must not shy away from this issue. I use visual…

  18. Granular computing: perspectives and challenges.

    Science.gov (United States)

    Yao, JingTao; Vasilakos, Athanasios V; Pedrycz, Witold

    2013-12-01

    Granular computing, as a new and rapidly growing paradigm of information processing, has attracted many researchers and practitioners. Granular computing is an umbrella term to cover any theories, methodologies, techniques, and tools that make use of information granules in complex problem solving. The aim of this paper is to review foundations and schools of research and to elaborate on current developments in granular computing research. We first review some basic notions of granular computing. Classification and descriptions of various schools of research in granular computing are given. We also present and identify some research directions in granular computing.

  19. Centrifuge modelling of granular flows

    Science.gov (United States)

    Cabrera, Miguel Angel; Wu, Wei

    2015-04-01

    A common characteristic of mass flows like debris flows, rock avalanches and mudflows is that gravity is their main driving force. Gravity defines the intensity and duration of the main interactions between particles and their surrounding media (particle-particle, particle-fluid, fluid-fluid). At the same time, gravity delimits the occurrence of phase separation, inverse segregation, and mass consolidation, among other phenomena. Therefore, in the understanding of the flow physics it is important to account for the scaling of gravity in scaled models. In this research, a centrifuge model is developed to model free surface granular flows down an incline at controlled gravity conditions. Gravity is controlled by the action of an induced inertial acceleration field resulting from the rotation of the model in a geotechnical centrifuge. The characteristics of the induced inertial acceleration field during flow are discussed and validated via experimental data. Flow heights, velocity fields, basal pressure and impact forces are measured for a range of channel inclinations and gravity conditions. Preliminary results enlighten the flow characteristics at variable gravity conditions and open a discussion on the simulation of large scale processes at a laboratory scale. Further analysis on the flow physics brings valuable information for the validation of granular flows rheology.

  20. Applying Integrated Computer Assisted Media (ICAM in Teaching Vocabulary

    Directory of Open Access Journals (Sweden)

    Opick Dwi Indah

    2015-02-01

    Full Text Available The objective of this research was to find out whether the use of integrated computer assisted media (ICAM is effective to improve the vocabulary achievement of the second semester students of Cokroaminoto Palopo University. The population of this research was the second semester students of English department of Cokroaminoto Palopo University in academic year 2013/2014. The samples of this research were 60 students and they were placed into two groups: experimental and control group where each group consisted of 30 students. This research used cluster random sampling technique. The research data was collected by applying vocabulary test and it was analyzed by using descriptive and inferential statistics. The result of this research was integrated computer assisted media (ICAM can improve vocabulary achievement of the students of English department of Cokroaminoto Palopo University. It can be concluded that the use of ICAM in the teaching vocabulary is effective to be implemented in improving the students’ vocabulary achievement.

  1. Development of Animation Teaching Media on the Topic of The Property of The Father

    Directory of Open Access Journals (Sweden)

    Preedawon Kadmateekarun

    2015-01-01

    Full Text Available The objective of this research was to develop animation teaching media on the topic of The Property of the Father to teach for students to understand the concept of sufficiency. The animation was developed to evaluate the performance of a sample of 50 grade 4-5 students at Wat Don Sali School. The results were as the achievement of the students who were taught with the animation was .05 significantly and students had a high level of satisfaction with the animation.

  2. Digital Media Art Professional Practical Teaching System Construction%数字媒体艺术专业实践教学体系建设

    Institute of Scientific and Technical Information of China (English)

    贺楠; 梁玉清

    2011-01-01

    Digital media industry which is the 21st world of the development of knowledge economy,is the core industry after the IT industry and a new economic growth point,our country also with the development of times to accelerate the multimedia digital art talents training steps.But it is undeniable is digital media art teaching system there are still some problems.In this paper,the characteristics of digital media art paper is analyzed on the basis of digital media art market and docking not compatible development present situation,in view of practice teaching from daily experimental course teaching management,open open lab,project practice group activities and organize and conduct professional teaching establishment and market integration of internship from four aspects,and puts forward the media art practical teaching system construction ideas.%针对数字媒体艺术教学体系存在的问题,在阐述数字媒体艺术特点的基础上,分析数字媒体艺术与市场对接不协调的发展现状。结合哈尔滨师范大学传媒学院实践经验和取得的成果,提出数字媒体艺术专业实践教学体系构建的设想。

  3. Learning and innovation: a methodological proposal from the teaching of Media Management

    Directory of Open Access Journals (Sweden)

    F Peinado-Miguel

    2013-02-01

    Full Text Available After its adaptation to the EHEA, the Department of Journalism IV of the Complutense University of Madrid began a project of methodological renovation and educational innovation –linked to an R&D project– in the teaching of Media Management, with the aim of providing future communication professionals with the skills required by the new business reality. The project was developed in different stages and was structured along the following lines of action: use of ICTs and Web 2.0 tools to develop activities that put new energy into the learning process: podcasts, interviews with executive directors and managers, entrepreneurial projects 2.0, intensive use of the Virtual Campus and blogs. In addition the teaching innovation project involved collaborative work to resolve real cases, with the implementation of the Educlick system’s software and hardware. This article presents the foundations and results of the new learning methodology model, which could be extrapolated to the teaching of other subjects of journalism

  4. Transport and abatement of fluorescent silica nanoparticle (SiO_2 NP) in granular filtration: effect of porous media and ionic strength

    International Nuclear Information System (INIS)

    Zeng, Chao; Shadman, Farhang; Sierra-Alvarez, Reyes

    2017-01-01

    The extensive production and application of engineered silica nanoparticles (SiO_2 NPs) will inevitably lead to their release into the environment. Granular media filtration, a widely used process in water and wastewater treatment plants, has the potential for NP abatement. In this work, laboratory-scale column experiments were performed to study the transport and retention of SiO_2 NPs on three widely used porous materials, i.e., sand, anthracite, and granular activated carbon (GAC). Synthetic fluorescent core-shell SiO_2 NPs (83 nm) were used to facilitate NP detection. Sand showed very low capacity for SiO_2 filtration as this material had a surface with limited surface area and a high concentration of negative charge. Also, we found that the stability and transport of SiO_2 NP were strongly dependent on the ionic strength of the solution. Increasing ionic strength led to NP agglomeration and facilitated SiO_2 NP retention, while low ionic strength resulted in release of captured NPs from the sand bed. Compared to sand, anthracite and GAC showed higher affinity for SiO_2 NP capture. The superior capacity of GAC was primarily due to its porous structure and high surface area. A process model was developed to simulate NP capture in the packed bed columns and determine fundamental filtration parameters. This model provided an excellent fit to the experimental data. Taken together, the results obtained indicate that GAC is an interesting material for SiO_2 NP filtration.

  5. Transport and abatement of fluorescent silica nanoparticle (SiO2 NP) in granular filtration: effect of porous media and ionic strength

    Science.gov (United States)

    Zeng, Chao; Shadman, Farhang; Sierra-Alvarez, Reyes

    2017-03-01

    The extensive production and application of engineered silica nanoparticles (SiO2 NPs) will inevitably lead to their release into the environment. Granular media filtration, a widely used process in water and wastewater treatment plants, has the potential for NP abatement. In this work, laboratory-scale column experiments were performed to study the transport and retention of SiO2 NPs on three widely used porous materials, i.e., sand, anthracite, and granular activated carbon (GAC). Synthetic fluorescent core-shell SiO2 NPs (83 nm) were used to facilitate NP detection. Sand showed very low capacity for SiO2 filtration as this material had a surface with limited surface area and a high concentration of negative charge. Also, we found that the stability and transport of SiO2 NP were strongly dependent on the ionic strength of the solution. Increasing ionic strength led to NP agglomeration and facilitated SiO2 NP retention, while low ionic strength resulted in release of captured NPs from the sand bed. Compared to sand, anthracite and GAC showed higher affinity for SiO2 NP capture. The superior capacity of GAC was primarily due to its porous structure and high surface area. A process model was developed to simulate NP capture in the packed bed columns and determine fundamental filtration parameters. This model provided an excellent fit to the experimental data. Taken together, the results obtained indicate that GAC is an interesting material for SiO2 NP filtration.

  6. Granular gas dynamics

    CERN Document Server

    Brilliantov, Nikolai

    2003-01-01

    While there is not yet any general theory for granular materials, significant progress has been achieved for dilute systems, also called granular gases. The contributions in this book address both the kinetic approach one using the Boltzmann equation for dissipative gases as well as the less established hydrodynamic description. The last part of the book is devoted to driven granular gases and their analogy with molecular fluids. Care has been taken so as to present the material in a pedagogical and self-contained way and this volume will thus be particularly useful to nonspecialists and newcomers to the field.

  7. Social Media and Teaching

    DEFF Research Database (Denmark)

    Tække, Jesper; Paulsen, Michael

    New research in the Danish upper secondary schools shows that social media like Facebook is the number one attention diverts from the interaction about educational subjects in the classroom. At the same time international research shows that there is a great potential in using social media....... The overriding purpose of the paper is to provide a research-based input to the discussion about the role of social media in schools....... the past seven years (Paulsen & Tække 2009, 2010; Tække & Paulsen 2010). To find out if and how the gap can be reduced, we have initiated the action research project The Socio Media Education Experiment, and in the paper we explain both the background for the project and its preliminary results...

  8. Spreading of a granular droplet

    Science.gov (United States)

    Clement, Eric; Sanchez, Ivan; Raynaud, Franck; Lanuza, Jose; Andreotti, Bruno; Aranson, Igor

    2008-03-01

    The influence of controlled vibrations on the granular rheology is investigated in a specifically designed experiment in which a granular film spreads under the action of horizontal vibrations. A nonlinear diffusion equation is derived theoretically that describes the evolution of the deposit shape. A self-similar parabolic shape (the``granular droplet'') and a spreading dynamics are predicted that both agree quantitatively with the experimental results. The theoretical analysis is used to extract effective friction coefficients between the base and the granular layer under sustained and controlled vibrations. A shear thickening regime characteristic of dense granular flows is evidenced at low vibration energy, both for glass beads and natural sand. Conversely, shear thinning is observed at high agitation.

  9. From continuum analytical description to discrete numerical modelling of localized fluidization in granular media

    Directory of Open Access Journals (Sweden)

    Puig i Montellà Eduard

    2017-01-01

    Full Text Available We present analytical and numerical results on localized fluidization within a granular layer subjected to a local injection of fluid. As the injection rate increases the three different regimes previously reported in the literature are recovered: homogeneous expansion of the bed, fluidized cavity in which fluidization starts developing above the injection area, and finally the chimney of fluidized grains when the fluidization zone reaches the free surface. The analytical approach is at the continuum scale, based on Darcy’s law and Therzaghi’s effective stress principle. It provides a good description of the phenomenon as long as the porosity of the granular assembly remains relatively homogeneous. The numerical approach is at the particle scale based on the coupled DEM-PFV method. It tackles the more heterogeneous situations which occur at larger injection rates. A direct link is evidenced between the occurrence of the different regimes of fluidization and the injection aperture. Finally, the merging of chimneys in case of two injection points is investigated.

  10. Effective transport properties for the pyridine-granular activated carbon adsorption system

    OpenAIRE

    Baz-Rodríguez, S. A.; Ocampo-Pérez, R.; Ruelas-Leyva, J. P.; Aguilar-Madera, C. G.

    2012-01-01

    In this work, the kinetics of pyridine adsorption onto granular activated carbon was studied from the point of view of an up-scaling process by using the method of volume averaging. The pore and surface effective diffusivities were estimated by supposing simple microscale geometries (ordered media of cylinders and spheres) and those of images processed from SEM (Scanning Electron Microscopy) micrographs. In addition, as a rough estimate, the point surface diffusivity is reported. The results ...

  11. Dissipation consistent fabric tensor definition from DEM to continuum for granular media

    Science.gov (United States)

    Li, X. S.; Dafalias, Y. F.

    2015-05-01

    In elastoplastic soil models aimed at capturing the impact of fabric anisotropy, a necessary ingredient is a measure of anisotropic fabric in the form of an evolving tensor. While it is possible to formulate such a fabric tensor based on indirect phenomenological observations at the continuum level, it is more effective and insightful to have the tensor defined first based on direct particle level microstructural observations and subsequently deduce a corresponding continuum definition. A practical means able to provide such observations, at least in the context of fabric evolution mechanisms, is the discrete element method (DEM). Some DEM defined fabric tensors such as the one based on the statistics of interparticle contact normals have already gained widespread acceptance as a quantitative measure of fabric anisotropy among researchers of granular material behavior. On the other hand, a fabric tensor in continuum elastoplastic modeling has been treated as a tensor-valued internal variable whose evolution must be properly linked to physical dissipation. Accordingly, the adaptation of a DEM fabric tensor definition to a continuum constitutive modeling theory must be thermodynamically consistent in regards to dissipation mechanisms. The present paper addresses this issue in detail, brings up possible pitfalls if such consistency is violated and proposes remedies and guidelines for such adaptation within a recently developed Anisotropic Critical State Theory (ACST) for granular materials.

  12. Water flow exchange characteristics in coarse granular filter media

    DEFF Research Database (Denmark)

    Andreasen, Rune Røjgaard; Pugliese, Lorenzo; Poulsen, Tjalfe

    2013-01-01

    Elution of inhibitory metabolites is a key parameter controlling the efficiency of air cleaning bio- and biotrickling filters. To the authors knowledge no studies have yet considered the relationship between specific surface area related elution velocity and physical media characteristics, which...... in this study are performed at a concurrent airflow of 0.3 m s−1, water irrigation rates of 1–21 cm h−1 in materials with particle diameters ranging from 2 to 14 mm to represent media and operation conditions relevant for low flow biotrickling filter design. Specific surface area related elution velocity...... distribution was closely related to the filter water content, water irrigation rate, media specific surface area and particle size distribution. A predictive model linking the specific surface area related elution velocity distribution to irrigation rate, specific surface area and particle size distribution...

  13. Type-2 fuzzy granular models

    CERN Document Server

    Sanchez, Mauricio A; Castro, Juan R

    2017-01-01

    In this book, a series of granular algorithms are proposed. A nature inspired granular algorithm based on Newtonian gravitational forces is proposed. A series of methods for the formation of higher-type information granules represented by Interval Type-2 Fuzzy Sets are also shown, via multiple approaches, such as Coefficient of Variation, principle of justifiable granularity, uncertainty-based information concept, and numerical evidence based. And a fuzzy granular application comparison is given as to demonstrate the differences in how uncertainty affects the performance of fuzzy information granules.

  14. Some effects of gas-induced fluidization in dry granular media

    Energy Technology Data Exchange (ETDEWEB)

    Nermoen, Anders

    2010-06-15

    The main body of this thesis consists of three papers in which aspects of fluid induced deformation in granular materials are studied. Insight from experiments, dimensional analysis, numerical modeling and analytic predictions are combined to interpret observations various aspects of piercement structures in the geological record. A fourth paper is included showing how analogue modeling has been used to understand a geological processes. Paper 1 presents experimental work on the segregation pattern forming in partially fluidized, bi-modal sized granular mixtures. The experiments are performed on a vertically oriented Hele-Shaw cell (HS-cell), the narrow box between two parallel glass plates, filled with glass beads. Gas flow is imparted through the bottom of the bed causing fluidization when the system is driven at velocities exceeding a critical limit. The co-existence of fluidized and static zones is termed partial fluidization and occurs when the imposed gas flux is insufficient to fluidize the whole system. Within the fluidized zones, the particles re-organize and the large particles sediment down while the small particles remains fluidized. The re-organization is caused by differences in the ratio of the weight to the viscous drag. A pipe-like pattern develops due to a feedback mechanism in which the flow is focused through domains dominated by large particles. The focusing of the flow localizes the fluidization, which in turn enables the sedimentation of the large grains. Paper 2 presents an experimental and analytical study of the critical conditions for fluidization of a dry granular material. Based on the experiments, we find that the critical velocity of fluidization scales almost linear with the ratio of the filling height to the inlet width. An analytic model for the pressure field is obtained by solving the Laplace equation for the velocity boundary conditions given by the geometry of the experimental setup. By integrating the vertical component of the

  15. Granular-relational data mining how to mine relational data in the paradigm of granular computing ?

    CERN Document Server

    Hońko, Piotr

    2017-01-01

    This book provides two general granular computing approaches to mining relational data, the first of which uses abstract descriptions of relational objects to build their granular representation, while the second extends existing granular data mining solutions to a relational case. Both approaches make it possible to perform and improve popular data mining tasks such as classification, clustering, and association discovery. How can different relational data mining tasks best be unified? How can the construction process of relational patterns be simplified? How can richer knowledge from relational data be discovered? All these questions can be answered in the same way: by mining relational data in the paradigm of granular computing! This book will allow readers with previous experience in the field of relational data mining to discover the many benefits of its granular perspective. In turn, those readers familiar with the paradigm of granular computing will find valuable insights on its application to mining r...

  16. High-Performance Modeling and Simulation of Anchoring in Granular Media for NEO Applications

    Science.gov (United States)

    Quadrelli, Marco B.; Jain, Abhinandan; Negrut, Dan; Mazhar, Hammad

    2012-01-01

    NASA is interested in designing a spacecraft capable of visiting a near-Earth object (NEO), performing experiments, and then returning safely. Certain periods of this mission would require the spacecraft to remain stationary relative to the NEO, in an environment characterized by very low gravity levels; such situations require an anchoring mechanism that is compact, easy to deploy, and upon mission completion, easy to remove. The design philosophy used in this task relies on the simulation capability of a high-performance multibody dynamics physics engine. On Earth, it is difficult to create low-gravity conditions, and testing in low-gravity environments, whether artificial or in space, can be costly and very difficult to achieve. Through simulation, the effect of gravity can be controlled with great accuracy, making it ideally suited to analyze the problem at hand. Using Chrono::Engine, a simulation pack age capable of utilizing massively parallel Graphic Processing Unit (GPU) hardware, several validation experiments were performed. Modeling of the regolith interaction has been carried out, after which the anchor penetration tests were performed and analyzed. The regolith was modeled by a granular medium composed of very large numbers of convex three-dimensional rigid bodies, subject to microgravity levels and interacting with each other with contact, friction, and cohesional forces. The multibody dynamics simulation approach used for simulating anchors penetrating a soil uses a differential variational inequality (DVI) methodology to solve the contact problem posed as a linear complementarity method (LCP). Implemented within a GPU processing environment, collision detection is greatly accelerated compared to traditional CPU (central processing unit)- based collision detection. Hence, systems of millions of particles interacting with complex dynamic systems can be efficiently analyzed, and design recommendations can be made in a much shorter time. The figure

  17. PENERAPAN MODEL PEMBELAJARAN CONTEXTUAL TEACHING AND LEARNING DENGAN MENGGUNAKAN MEDIA MODUL DALAM MENINGKATKAN HASIL BELAJAR MATA PELAJARAN AKUNTANSI PADA SISWA SMA SE-KOTA BANDUNG

    Directory of Open Access Journals (Sweden)

    Imas Purnamasari

    2014-04-01

    Full Text Available The results of student learning is a combination of various factors that affect the overall learning process. The phenomenon in this study is the lack of student learning outcomes are seen from the results of the national exam on economic subjects, especially the material accounting, one of the causes of the problems in the learning process, namely on how to give lessons conducted by teachers, and the use of instructional media, especially the media module. This study, use the method of the experiment to make a difference between the results of the study on the student teaching and learning by contextual the use of the media, the students are not using the models of the contextual teaching and learning to use media. Results of the analysis of 10 schools in the city of bandung at 8 school with the influence of contextual teaching and learning module, using this hypothesis can be seen from the increase is the result of study to students.

  18. Transport and abatement of fluorescent silica nanoparticle (SiO{sub 2} NP) in granular filtration: effect of porous media and ionic strength

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Chao, E-mail: chaozeng@email.arizona.edu; Shadman, Farhang; Sierra-Alvarez, Reyes [University of Arizona, Department of Chemical and Environmental Engineering (United States)

    2017-03-15

    The extensive production and application of engineered silica nanoparticles (SiO{sub 2} NPs) will inevitably lead to their release into the environment. Granular media filtration, a widely used process in water and wastewater treatment plants, has the potential for NP abatement. In this work, laboratory-scale column experiments were performed to study the transport and retention of SiO{sub 2} NPs on three widely used porous materials, i.e., sand, anthracite, and granular activated carbon (GAC). Synthetic fluorescent core-shell SiO{sub 2} NPs (83 nm) were used to facilitate NP detection. Sand showed very low capacity for SiO{sub 2} filtration as this material had a surface with limited surface area and a high concentration of negative charge. Also, we found that the stability and transport of SiO{sub 2} NP were strongly dependent on the ionic strength of the solution. Increasing ionic strength led to NP agglomeration and facilitated SiO{sub 2} NP retention, while low ionic strength resulted in release of captured NPs from the sand bed. Compared to sand, anthracite and GAC showed higher affinity for SiO{sub 2} NP capture. The superior capacity of GAC was primarily due to its porous structure and high surface area. A process model was developed to simulate NP capture in the packed bed columns and determine fundamental filtration parameters. This model provided an excellent fit to the experimental data. Taken together, the results obtained indicate that GAC is an interesting material for SiO{sub 2} NP filtration.

  19. Media Pembelajaran Sejarah di SMK Negeri Pontianak

    Directory of Open Access Journals (Sweden)

    Astrini Eka Putri

    2017-08-01

    Full Text Available Research is expected could become the foundation of renewal in the use of media teaching history in state vocational schools in Pontianak. Based on it, then the researcher wants to describe about media learning customarily using by teachers in the process teaching history. Researcher interested to arrange research with a title “Media Teaching History in State Vocational Schools in Pontianak“. Media uses teaching history in state vocational schools Pontianak has been good enough, since on average teachers using the existing facilities at the school in order to support learning activity. Learning activity history done by the teacher in this has been good enough, because it is already employing variations learning that are attractive. In the teaching process in two classes not only uses the media learning of a textbook,  but had done some innovation that is by using media Microsoft Office PowerPoint.

  20. Particle filtration in consolidated granular systems

    International Nuclear Information System (INIS)

    Schwartz, L.M.; Wilkinson, D.J.; Bolsterli, M.; Hammond, P.

    1993-01-01

    Grain-packing algorithms are used to model the mechanical trapping of dilute suspensions of particles by consolidated granular media. We study the distribution of filtrate particles, the formation of a damage zone (internal filter cake), and the transport properties of the host--filter-cake composite. At the early stages of filtration, our simulations suggest simple relationships between the structure of the internal filter cake and the characteristics of the underlying host matrix. These relationships are then used to describe the dynamics of the filtration process. Depending on the grain size and porosity of the host matrix, calculated filtration rates may either be greater than (spurt loss) or less than (due to internal clogging) those predicted by standard surface-filtration models

  1. Media Education and Media Criticism in the Educational Process in Russia

    Science.gov (United States)

    Fedorov, Alexander; Levitskaya, Anastasia

    2017-01-01

    Media criticism and media education have a lot in common. For example, both media education and media criticism attach great importance to the development of analytical thinking of the audience. Indeed, one of the most important tasks of media education is precisely to teach the audience not only to analyze media texts of any types, but also to…

  2. Mathematical models of granular matter

    CERN Document Server

    Mariano, Paolo; Giovine, Pasquale

    2008-01-01

    Granular matter displays a variety of peculiarities that distinguish it from other appearances studied in condensed matter physics and renders its overall mathematical modelling somewhat arduous. Prominent directions in the modelling granular flows are analyzed from various points of view. Foundational issues, numerical schemes and experimental results are discussed. The volume furnishes a rather complete overview of the current research trends in the mechanics of granular matter. Various chapters introduce the reader to different points of view and related techniques. New models describing granular bodies as complex bodies are presented. Results on the analysis of the inelastic Boltzmann equations are collected in different chapters. Gallavotti-Cohen symmetry is also discussed.

  3. Media Literacy Bibliography.

    Science.gov (United States)

    Duncan, Barry

    1989-01-01

    Provides an up-to-date bibliography of resources available for teaching media literacy. Groups resources into the areas of media education methodology, mass media texts, general background, television, film, the news and medium of print, advertising, gender and the media, popular culture, popular music and rock video, periodicals, and…

  4. Professional and Social Media Sites (SMSs): Motives and Positive Values of Accommodating Social Media Sites (SMSs) in Teaching Practices according to Indonesian Professional Educators: A Case Study in Two Indonesian Higher Educational Institutions

    Science.gov (United States)

    Luke, J. Y.; Billy, Y. L.

    2017-09-01

    In millennium era, the proliferating Social Media Sites (SMSs) has not only brought increasing demands for all humans, but also creates positive values, specifically for the professional educators or lecturers in any ages. This study envisages the positive values of accommodating Social Media Sites (SMSs) in teaching practices according to the professional educators. Thirty professional educators, i.e. the lecturers, from two universities (i.e. Multimedia Nusantara University and Bina Nusantara University) has participated in this study. The data was collected from the survey by means of questionnaires, analysed using percentages, and exposed the results descriptively. The findings reflected that the positive values of accommodating Social Media Sites in teaching practices were to develop social skills and improve academic skills. However among the two values, the latter was highly influencing the professional educators because of the four reasons: enabling to do tutorial lessons, providing online discussion space with experts or guest lecturers, assisting in doing peer-review and peer-editing, and enhancing the receptive skills, the productive skills, and also the critical thinking skills of the users in SMSs, especially the professional educators or lecturers. Thus, accommodating Social Media Sites (SMSs) in teaching practices is essential for professional educators in Indonesia.

  5. Correlations and the Ring-Kinetic Equation in Dense Sheared Granular Flows

    Science.gov (United States)

    Kumaran, V.

    A formal way of deriving fluctuation-correlation relations in densesheared granular media, starting with the Enskog approximation for the collision integral in the Chapman-Enskog theory, is discussed. The correlation correction to the viscosity is obtained using the ring-kinetic equation, in terms of the correlations in the hydrodynamic modes of the linearised Enskog equation. It is shown that the Green-Kubo formula for the shear viscosity emerges from the two-body correlation function obtained from the ring-kinetic equation.

  6. A Two-Phase Solid/Fluid Model for Dense Granular Flows Including Dilatancy Effects

    Science.gov (United States)

    Mangeney, Anne; Bouchut, Francois; Fernandez-Nieto, Enrique; Narbona-Reina, Gladys

    2015-04-01

    We propose a thin layer depth-averaged two-phase model to describe solid-fluid mixtures such as debris flows. It describes the velocity of the two phases, the compression/dilatation of the granular media and its interaction with the pore fluid pressure, that itself modifies the friction within the granular phase (Iverson et al., 2010). The model is derived from a 3D two-phase model proposed by Jackson (2000) based on the 4 equations of mass and momentum conservation within the two phases. This system has 5 unknowns: the solid and fluid velocities, the solid and fluid pressures and the solid volume fraction. As a result, an additional equation inside the mixture is necessary to close the system. Surprisingly, this issue is inadequately accounted for in the models that have been developed on the basis of Jackson's work (Bouchut et al., 2014). In particular, Pitman and Le replaced this closure simply by imposing an extra boundary condition at the surface of the flow. When making a shallow expansion, this condition can be considered as a closure condition. However, the corresponding model cannot account for a dissipative energy balance. We propose here an approach to correctly deal with the thermodynamics of Jackson's equations. We close the mixture equations by a weak compressibility relation involving a critical density, or equivalently a critical pressure. Moreover, we relax one boundary condition, making it possible for the fluid to escape the granular media when compression of the granular mass occurs. Furthermore, we introduce second order terms in the equations making it possible to describe the evolution of the pore fluid pressure in response to the compression/dilatation of the granular mass without prescribing an extra ad-hoc equation for the pore pressure. We prove that the energy balance associated with this Jackson closure is dissipative, as well as its thin layer associated model. We present several numerical tests for the 1D case that are compared to the

  7. A Problem-Based Learning Approach of Teaching Mathematics to Media Technology Students Using a Game Engine

    DEFF Research Database (Denmark)

    Triantafyllou, Evangelia; Misfeldt, Morten; Timcenko, Olga

    2015-01-01

    In this article, we present our idea of using a game engine (Unity) to teach Media Technology students mathematics-related concepts. In order to observe how the introduction of a technological tool, namely the game engine, changes the practices in mathematical work, we adopted the anthropological...

  8. Balancing media environments

    DEFF Research Database (Denmark)

    Olesen, Mogens

    The paper examines how students in Danish upper secondary schools experience the uses and effects of the digital environment in relation to their school activities. Theoretically a media ecological perspective (Strate 2006) is applied which understands teaching and learning practices as shaped...... by the interrelation between teacher, student and the media technologies. According to this perspective, media creates an environment that shapes our possibilities for acting and communicating. In a basic sense, teaching and learning is a communicative situation where, traditionally, the teacher sends information...... to the receiving students through a medium (e.g. speech, blackboard, book or online learning platform). Digital media challenge this situation due to their affordances (Gibson 1979) for interactivity. Affordance has become an increasingly popular term within media studies for describing a complementary...

  9. 10,000 - A reason to study granular heat convection

    Energy Technology Data Exchange (ETDEWEB)

    Einav, I.; Rognon, P.; Gan, Y.; Miller, T.; Griffani, D. [Particles and Grains Laboratory, School of Civil Engineering, University of Sydney, Sydney, NSW 2006 (Australia)

    2013-06-18

    In sheared granular media, particle motion is characterized by vortex-like structures; here this is demonstrated experimentally for disks system undergoing indefinite deformation during simple shear, as often imposed by the rock masses hosting earthquake fault gouges. In traditional fluids it has been known for years that vortices represent a major factor of heat transfer enhancement via convective internal mixing, but in analyses of heat transfer through earthquake faults and base planes of landslides this has been continuously neglected. Can research proceed by neglecting heat convection by internal mixing? Our answer is astonishingly far from being yes.

  10. Impact Compaction of a Granular Material

    Science.gov (United States)

    Fenton, Gregg; Asay, Blaine; Todd, Steve; Grady, Dennis

    2017-06-01

    The dynamic behavior of granular materials has importance to a variety of engineering applications. Although, the mechanical behavior of granular materials have been studied extensively for several decades, the dynamic behavior of these materials remains poorly understood. High-quality experimental data are needed to improve our general understanding of granular material compaction physics. This paper describes how an instrumented plunger impact system can be used to measure the compaction process for granular materials at high and controlled strain rates and subsequently used for computational modelling. The experimental technique relies on a gas-gun driven plunger system to generate a compaction wave through a volume of granular material. This volume of material has been redundantly instrumented along the bed length to track the progression of the compaction wave, and the piston displacement is measured with Photon Doppler Velocimetry (PDV). Using the gathered experimental data along with the initial material tap density, a granular material equation of state can be determined.

  11. Enriching Higher Education with Social Media: Development and Evaluation of a Social Media Toolkit

    Science.gov (United States)

    Gülbahar, Yasemin; Rapp, Christian; Kilis, Selcan; Sitnikova, Anna

    2017-01-01

    While ubiquitous in everyday use, in reality, social media usage within higher education teaching has expanded quite slowly. Analysis of social media usage of students and instructors for teaching, learning, and research purposes across four countries (Russia, Turkey, Germany, and Switzerland) showed that many higher education instructors actively…

  12. Teaching English through Mass Media

    Directory of Open Access Journals (Sweden)

    Vilma Tafani

    2009-03-01

    Full Text Available This article aims at analyzing the importance of using Mass Media in the classroom and finding the ways how to use Printed and Audio-visual Media. It is the result of an in-depth study, surveys and questionnaires thus trying to make the ideas in this article more trustworthy. It is based not only on the literature review but also on long personal experience. It is a brief description of some practical examples and some tips for novice teachers. Further more, this article tends to deal with some of the key issues of using media in the classroom. Here are included some of the findings of my research work on a post-doctorate Fulbright Program in 2001. The following issues are open for discussion: the importance of Media in general and in education in particular; Media are persuasive and pervasive, newspapers, magazines, radio, television and internet in the classroom, etc.

  13. Granular flows: fundamentals and applications

    Science.gov (United States)

    Cleary, Paul W.

    DEM allows the prediction of complex industrial and geophysical particle flows. The importance of particle shape is demonstrated through a series of simple examples. Shape controls resistance to shear, the magnitude of collision stress, dilation and the angle of repose. We use a periodic flow of a bed of particles to demonstrate the different states of granular matter, the generation of dilute granular flow when granular temperature is high and the flow dependent nature of the granular thermodynamic boundary conditions. A series of industrial case studies examines how DEM can be used to understand and improve processes such as separation, mixing, grinding, excavation, hopper discharge, metering and conveyor interchange. Finally, an example of landslide motion over real topography is presented.

  14. Using Social Media to Increase Accessibility to Online Teaching Resources.

    Science.gov (United States)

    O'Kelly, B; McHugh, S; McHugh, T; Fady, N; Boyle, E; Hill, A D K

    2015-09-01

    The key learning points of Surgical Grand Rounds (SGR) are often not accessible at times of exam revision for students. We sought to use Twitter as an online teaching repository. A SGR Twitter profile was created. 23 SGR presentations were made accessible on Twitter over a 3 month period. 93 students were invited to complete a questionnaire assessing usage of the repository. 84 (90%) in total responded, of these, 25 (80.6%) felt that the online provision of SGR through twitter was "useful". The majority (71%) felt that the online content was easily accessible. The novel use of social media is a useful adjunctive educational tool in accessing an online repository of SGR presentations.

  15. Granular flows in constrained geometries

    Science.gov (United States)

    Murthy, Tejas; Viswanathan, Koushik

    Confined geometries are widespread in granular processing applications. The deformation and flow fields in such a geometry, with non-trivial boundary conditions, determine the resultant mechanical properties of the material (local porosity, density, residual stresses etc.). We present experimental studies of deformation and plastic flow of a prototypical granular medium in different nontrivial geometries- flat-punch compression, Couette-shear flow and a rigid body sliding past a granular half-space. These geometries represent simplified scaled-down versions of common industrial configurations such as compaction and dredging. The corresponding granular flows show a rich variety of flow features, representing the entire gamut of material types, from elastic solids (beam buckling) to fluids (vortex-formation, boundary layers) and even plastically deforming metals (dead material zone, pile-up). The effect of changing particle-level properties (e.g., shape, size, density) on the observed flows is also explicitly demonstrated. Non-smooth contact dynamics particle simulations are shown to reproduce some of the observed flow features quantitatively. These results showcase some central challenges facing continuum-scale constitutive theories for dynamic granular flows.

  16. Granular activated carbon for removal of organic matter and turbidity from secondary wastewater.

    Science.gov (United States)

    Hatt, J W; Germain, E; Judd, S J

    2013-01-01

    A range of commercial granular activated carbon (GAC) media have been assessed as pretreatment technologies for a downstream microfiltration (MF) process. Media were assessed on the basis of reduction in both organic matter and turbidity, since these are known to cause fouling in MF membranes. Isotherm adsorption analysis through jar testing with supplementary column trials revealed a wide variation between the different adsorbent materials with regard to organics removal and adsorption kinetics. Comparison with previous work using powdered activated carbon (PAC) revealed that for organic removal above 60% the use of GAC media incurs a significantly lower carbon usage rate than PAC. All GACs tested achieved a minimum of 80% turbidity removal. This combination of turbidity and organic removal suggests that GAC would be expected to provide a significant reduction in fouling of a downstream MF process with improved product water quality.

  17. Teaching Students about Violent Media Effects

    Science.gov (United States)

    Bushman, Brad J.

    2018-01-01

    Although violent entertainment has existed for centuries, the media have made it more accessible than ever before. In modern societies, people are immersed in media, like fish in water. Using hand-held devices, people can consume media just about anywhere they want, anytime they want. Moreover, violence is a common theme in the media, and research…

  18. Granular boycott effect: How to mix granulates

    Science.gov (United States)

    Duran, J.; Mazozi, T.

    1999-11-01

    Granular material can display the basic features of the Boycott effect in sedimentation. A simple experiment shows that granular material falls faster in an inclined tube than in a vertical tube, in analogy with the Boycott effect. As long as the inclination of the tube is above the avalanche threshold, descent of granular material in the tube causes internal convection which in turn results in an efficient mixture of the granular components. By contrast, as in analogous experiments in two dimensions, a vertical fall of granular material occurs via successive block fragmentation, resulting in poor mixing.

  19. Media Anthropology: A Theoretical Framework

    Science.gov (United States)

    Eiselein, E. B.; Topper, Martin

    1976-01-01

    Media anthropology, a diverse field, has involved nearly all the major subdisciplines of anthropology and most of the major media in five different areas of interaction: the study of media, reaching the public, gathering data, teaching with media, and applied media anthropology. (NQ)

  20. Stoneley waves in a non-homogeneous orthotropic granular medium under the influence of gravity

    Directory of Open Access Journals (Sweden)

    S. M. Ahmed

    2005-01-01

    Full Text Available The aim of this paper is to investigate the Stoneley waves in a non-homogeneous orthotropic granular medium under the influence of a gravity field. The frequency equation obtained, in the form of a sixth-order determinantal expression, is in agreement with the corresponding result when both media are elastic. The frequency equation when the gravity field is neglected has been deduced as a particular case.

  1. 2nd conference on Continuous Media with Microstructure

    CERN Document Server

    Kuczma, Mieczysław

    2016-01-01

    This book presents research advances in the field of Continuous Media with Microstructure and considers the three complementary pillars of mechanical sciences: theory, research and computational simulation. It focuses on the following problems: thermodynamic and mathematical modeling of materials with extensions of classical constitutive laws, single and multicomponent media including modern multifunctional materials, wave propagation, multiscale and multiphysics processes, phase transformations, and porous, granular and composite materials. The book presents the proceedings of the 2nd Conference on Continuous Media with Microstructure, which was held in 2015 in Łagów, Poland, in memory of Prof. Krzysztof Wilmański. .

  2. Homogenization of discrete media

    International Nuclear Information System (INIS)

    Pradel, F.; Sab, K.

    1998-01-01

    Material such as granular media, beam assembly are easily seen as discrete media. They look like geometrical points linked together thanks to energetic expressions. Our purpose is to extend discrete kinematics to the one of an equivalent continuous material. First we explain how we build the localisation tool for periodic materials according to estimated continuum medium type (classical Cauchy, and Cosserat media). Once the bridge built between discrete and continuum media, we exhibit its application over two bidimensional beam assembly structures : the honey comb and a structural reinforced variation. The new behavior is then applied for the simple plan shear problem in a Cosserat continuum and compared with the real discrete solution. By the mean of this example, we establish the agreement of our new model with real structures. The exposed method has a longer range than mechanics and can be applied to every discrete problems like electromagnetism in which relationship between geometrical points can be summed up by an energetic function. (orig.)

  3. Homogenization of discrete media

    Energy Technology Data Exchange (ETDEWEB)

    Pradel, F.; Sab, K. [CERAM-ENPC, Marne-la-Vallee (France)

    1998-11-01

    Material such as granular media, beam assembly are easily seen as discrete media. They look like geometrical points linked together thanks to energetic expressions. Our purpose is to extend discrete kinematics to the one of an equivalent continuous material. First we explain how we build the localisation tool for periodic materials according to estimated continuum medium type (classical Cauchy, and Cosserat media). Once the bridge built between discrete and continuum media, we exhibit its application over two bidimensional beam assembly structures : the honey comb and a structural reinforced variation. The new behavior is then applied for the simple plan shear problem in a Cosserat continuum and compared with the real discrete solution. By the mean of this example, we establish the agreement of our new model with real structures. The exposed method has a longer range than mechanics and can be applied to every discrete problems like electromagnetism in which relationship between geometrical points can be summed up by an energetic function. (orig.) 7 refs.

  4. Using Social Media to Support Clinical Education.

    Science.gov (United States)

    Jackson, Jennifer

    2017-12-01

    Social media has been used increasingly as part of nursing education. Nurse educators at a large, multisite teaching hospital used social media to support clinical teaching. A series of educational images was created by nurse educators and shared across Facebook, Twitter, and Instagram. This campaign coincided with in-unit clinical education. Nurse educators can consider using social media as an adjunct to clinical teaching, especially in large hospital settings. J Contin Educ Nurs. 2017;48(12):541-542. Copyright 2017, SLACK Incorporated.

  5. The Potential of an Alliance of Media Literacy Education and Media Criticism in Russia

    Science.gov (United States)

    Levitskaya, Anastasia

    2015-01-01

    Media criticism and media literacy education have much in common. For example, media literacy education and media criticism attaches great importance to the development of analytical thinking audience. Indeed, one of the most important tasks of media literacy education is precisely to teach the audience not only to analyze media texts of any kinds…

  6. Settling properties of aerobic granular sludge (AGS) and aerobic granular sludge molasses (AGSM)

    Science.gov (United States)

    Mat Saad, Azlina; Aini Dahalan, Farrah; Ibrahim, Naimah; Yasina Yusuf, Sara; Aqlima Ahmad, Siti; Khalil, Khalilah Abdul

    2018-03-01

    Aerobic granulation technology is applied to treat domestic and industrial wastewater. The Aerobic granular sludge (AGS) cultivated has strong properties that appears to be denser and compact in physiological structure compared to the conventional activated sludge. It offers rapid settling for solid:liquid separation in wastewater treatment. Aerobic granules were developed using sequencing batch reactor (SBR) with intermittent aerobic - anaerobic mode with 8 cycles in 24 hr. This study examined the settling velocity performance of cultivated aerobic granular sludge (AGS) and aerobic granular sludge molasses (AGSM). The elemental composition in both AGS and AGSM were determined using X-ray fluorescence (XRF). The results showed that AGSM has higher settling velocity 30.5 m/h compared to AGS.

  7. Granular packing as model glass formers

    International Nuclear Information System (INIS)

    Wang Yujie

    2017-01-01

    Static granular packings are model hard-sphere glass formers. The nature of glass transition has remained a hotly debated issue. We review recent experimental progresses in using granular materials to study glass transitions. We focus on the growth of glass order with five-fold symmetry in granular packings and relate the findings to both geometric frustration and random first-order phase transition theories. (paper)

  8. Relating water and air flow characteristics in coarse granular materials

    DEFF Research Database (Denmark)

    Andreasen, Rune Røjgaard; Canga, Eriona; Poulsen, Tjalfe Gorm

    2013-01-01

    Water pressure drop as a function of velocity controls w 1 ater cleaning biofilter operation 2 cost. At present this relationship in biofilter materials must be determined experimentally as no 3 universal link between pressure drop, velocity and filter material properties have been established. 4...... Pressure drop - velocity in porous media is much simpler and faster to measure for air than for water. 5 For soils and similar materials, observations show a strong connection between pressure drop – 6 velocity relations for air and water, indicating that water pressure drop – velocity may be estimated 7...... from air flow data. The objective of this study was, therefore, to investigate if this approach is valid 8 also for coarse granular biofilter media which usually consists of much larger particles than soils. In 9 this paper the connection between the pressure drop – velocity relationships for air...

  9. Incorporating social media into dermatologic education.

    Science.gov (United States)

    Ko, Lauren N; Rana, Jasmine; Burgin, Susan

    2017-10-15

    In the current digital age, medical education has slowly evolved from the largely lecture-based teaching style of the past to incorporate more interactive pedagogical techniques, including use of social media. Already used readily by millennial trainees and clinicians, social media can also be used in innovative ways to teach trainees and facilitate continuing education among practicing clinicians. In this commentary, we discuss many learning benefits of social media and review potential pitfalls of employing social media in both trainee and physician dermatological education.

  10. Towards a Discourse for Criticism in Language Teaching: Analysis of Sociocultural Representations in Mass Media

    Directory of Open Access Journals (Sweden)

    Margarita Rosa Vargas Torres

    2010-10-01

    Full Text Available This article states that in order to exercise citizenship with responsibility, language teachers need to popularize a discourse for criticism in which students and teachers transcend tacit knowledge and common sense due to meta-cognition and argumentation and reach systematic knowledge and procedures posed by experts in the different disciplines. As illustrated inside, the source and objective of analysis by means of which this discourse can be contextualized in language teaching is the language of mass media and all the sociocultural and signifying practices that it invokes. We conclude that through the analysis of mass media it is possible to educate students with the basic knowledge and skills necessary to interact critically in the world.

  11. Evaluation of interlayer ferromagnetic coupling for stacked media by adding reference layer

    International Nuclear Information System (INIS)

    Tham, K K; Saito, S; Itagaki, N; Hinata, S; Takahashi, M; Hasegawa, D

    2011-01-01

    The trial for quantitative evaluation of interlayer ferromagnetic coupling between granular and cap layer in stacked media is reported. The evaluation is realized by analyzing M-H loop of stacked media with another reference layer added on the cap layer. The reference layer is antiferromagnetically coupled with the cap layer through non-magnetic spacer layer. In this experiment, Rh which leads to antiferromagnetic coupling constant along film normal direction of around 2 erg/cm 2 was used as non-magnetic spacer layer. According to the evaluation result done by this method, when thickness of the spacer Pd layer between granular layer and cap layer is increased to 1.1 nm, ferromagnetic coupling constant is weakened to 7.2 erg/cm 2 which results in reduction of saturation field.

  12. Impact-induced splash and spill in a quasi-confined granular medium

    Science.gov (United States)

    Ogale, S. B.; Shinde, S. R.; Karve, P. A.; Ogale, Abhijit S.; Kulkarni, A.; Athawale, A.; Phadke, A.; Thakurdas, R.

    2006-05-01

    The splash and spill effects caused by the impact of a ball dropped from a height into a granular medium held in a small open container are examined. Different granular media, namely rice, mustard seeds, cream of wheat and plastic beads are used. The quantity of spilled-over granular matter ( W, grams) is measured as a function of the ball-drop height and compared for different cases. Digital pictures of the splash process are also recorded. The quantity W is seen to vary approximately linearly with the energy of impact. Interestingly, a distinct upward jump is seen in the spilled quantity at specific impact energy in the case of mustard seeds, which have spherical shape and also exhibit some charging effects. Similar jump was also confirmed for the case of plastic beads with broadly similar properties. Although the parameters such as mass per grain and packing density for the case of mustard seeds are intermediate between those for rice and cream of wheat, the spill quantity for comparable impact energy is considerably higher in the former case. The possible reasons for this non-monotonicity of behavior are discussed in terms of the differences in grain shapes and properties. Experiments are also performed using plastic beads of the same type but with four different sizes to explore the dependence of spilled quantity on bead size. The container size dependence is also examined for various bead types. Interesting systematics are seen, which are discussed qualitatively.

  13. Diatomaceous earth and activated bauxite used as granular sorbents for the removal of sodium chloride vapor from hot flue gas

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.H.D.; Swift, W.M.; Johnson, I.

    1980-01-01

    Diatomaceous earth and activated bauxite were tested as granular sorbents for use as filter media in granular-bed filters for the removal of gaseous alkali metal compounds from the hot (800/sup 0/C) flue gas of PFBC. Tests were performed at atmospheric pressure, using NaCl vapor transported in relatively dry simulated flue gas of PFBC. Either a fixed-bed combustor or a high-temperature sorption test rig was used. The effects of sorbent bed temperature, superficial gas velocity, gas hourly space velocity, and NaCl-vapor concentration in flue gas on the sorption behavior of these two sorbents and their ultimate sorption capacities were determined. Both diatomaceous earth and activated bauxite were found to be very effective in removing NaCl vapor from flue gas. Preliminary cost evaluations showed that they are economically attractive as granular sorbents for cleaning alkali vapor from simulated flue gas.

  14. Developing Globally Minded, Critical Media Literacy Skills

    Directory of Open Access Journals (Sweden)

    Jason Harshman

    2017-05-01

    Full Text Available The transnational movement of people and ideas continues to reshape how we imagine places and cultures. Considering the volume of information and entertainment delivered and consumed via mass media, global educators are tasked with engaging students in learning activities that help them develop skill sets that include a globally minded, critical media literacy. Grounded in cultural studies and framed by Andreotti’s (2006 theory of critical GCE and Appadurai’s (1996 concept of mediascapes, this article examines how eleven global educators in as many countries used films to teach about what they considered to be the “6 C’s” of critical global media literacy: colonialism, capitalism, conflict, citizenship, and conscientious consumerism. How global educators foster globally minded, critical media literacy in their classrooms, the resources they use to teach about perspectives too often marginalized in media produced in the Global North, and how educating students about media informs action within global citizenship education is discussed. Findings from the study revealed that the opportunities to interact with fellow educators around the world inspired teacher’s to revisit concepts such as interconnectedness and crosscultural learning, along with shifts in thinking about how to teach media literacy by analyzing the coded messages present in the resources they use to teach about the world.

  15. Dynamic Deformation and Collapse of Granular Columns

    Science.gov (United States)

    Uenishi, K.; Tsuji, K.; Doi, S.

    2009-12-01

    Large dynamic deformation of granular materials may be found in nature not only in the failure of slopes and cliffs — due to earthquakes, rock avalanches, debris flows and landslides — but also in earthquake faulting itself. Granular surface flows often consist of solid grains and intergranular fluid, but the effect of the fluid may be usually negligible because the volumetric concentration of grains is in many cases high enough for interparticle forces to dominate momentum transport. Therefore, the investigation of dry granular flow of a mass might assist in further understanding of the above mentioned geophysical events. Here, utilizing a high-speed digital video camera system, we perform a simple yet fully-controlled series of laboratory experiments related to the collapse of granular columns. We record, at an interval of some microseconds, the dynamic transient granular mass flow initiated by abrupt release of a tube that contains dry granular materials. The acrylic tube is partially filled with glass beads and has a cross-section of either a fully- or semi-cylindrical shape. Upon sudden removal of the tube, the granular solid may fragment under the action of its own weight and the particles spread on a rigid horizontal plane. This study is essentially the extension of the previous ones by Lajeunesse et al. (Phys. Fluids 2004) and Uenishi and Tsuji (JPGU 2008), but the striped layers of particles in a semi-cylindrical tube, newly introduced in this contribution, allow us to observe the precise particle movement inside the granular column: The development of slip lines inside the column and the movement of particles against each other can be clearly identified. The major controlling parameters of the spreading dynamics are the initial aspect ratio of the granular (semi-)cylindrical column, the frictional properties of the horizontal plane (substrate) and the size of beads. We show the influence of each parameter on the average flow velocity and final radius

  16. How granular vortices can help understanding rheological and mixing properties of dense granular flows

    Directory of Open Access Journals (Sweden)

    Rognon Pierre

    2017-01-01

    Full Text Available Dense granular flows exhibit fascinating kinematic patterns characterised by strong fluctuations in grain velocities. In this paper, we analyse these fluctuations and discuss their possible role on macroscopic properties such as effective viscosity, non-locality and shear-induced diffusion. The analysis is based on 2D experimental granular flows performed with the stadium shear device and DEM simulations. We first show that, when subjected to shear, grains self-organised into clusters rotating like rigid bodies. The average size of these so-called granular vortices is found to increase and diverge for lower inertial numbers, when flows decelerate and stop. We then discuss how such a microstructural entity and its associated internal length scale, possibly much larger than a grain, may be used to explain two important properties of dense granular flows: (i the existence of shear-induced diffusion of grains characterised by a shear-rate independent diffusivity and (ii the development of boundary layers near walls, where the viscosity is seemingly lower than the viscosity far from walls.

  17. Inclusion/exclusion and Social Media

    DEFF Research Database (Denmark)

    Tække, Jesper

    Observations I Danish upper secondary schools show social media as either an attention distracting factor or as a factor drawing attention back to teaching again. The cursing point is if the teacher can manage to use social media in a constructive way, or if (s)he tries to prohibit or ignores...... the media use. At the same time social media has extensive scoop for improving both the organization and the quality of the teaching. In this paper we will put forward and analyze empirical findings showing that the community of the class also are challenged by informal networks, based on social media......, in the class, sometimes excluding the teacher form the class-interaction, sometimes excluding single students or groups from social interactions during school time....

  18. Protocol dependence of mechanical properties in granular systems.

    Science.gov (United States)

    Inagaki, S; Otsuki, M; Sasa, S

    2011-11-01

    We study the protocol dependence of the mechanical properties of granular media by means of computer simulations. We control a protocol of realizing disk packings in a systematic manner. In 2D, by keeping material properties of the constituents identical, we carry out compaction with various strain rates. The disk packings exhibit the strain rate dependence of the critical packing fraction above which the pressure becomes non-zero. The observed behavior contrasts with the well-studied jamming transitions for frictionless disk packings. We also observe that the elastic moduli of the disk packings depend on the strain rate logarithmically. Our results suggest that there exists a time-dependent state variable to describe macroscopic material properties of disk packings, which depend on its protocol.

  19. Promoting Media Literacy’ as Practicing “Media Reform”: Reflecting on Personal Experiences

    Directory of Open Access Journals (Sweden)

    Hui-Ju Tsai

    2016-04-01

    Full Text Available This paper assesses conceptions and practices in critical media literacy. In particular, it focuses on teaching experience and the processes which combine the educator’s reflection of theories of the ‘public sphere’, ‘media literacy’, and ‘communication civil rights’. The paper is divided into three main parts. The first of four sections will briefly cover the history of media reform and the relationship between the media reform movement and critical media literacy lessons in community colleges. It will connect this to the idea of ‘turn to the public’. The meaning and position of ‘media literacy’ in the broad media reform movement will also be analyzed. Following this, in the second section, conceptualizations of the ‘public sphere’, ‘public pedagogy’, and ‘critical media literacy pedagogy’ will be developed. Finally, three stages of the lesson design and practical interactions will be examined dialectically. In particular, the community college field research on my teaching experience will be described in the third section, and the suggestions, reflections and conclusions from the research will be examined in the last section.

  20. Thermal conductivity of granular materials

    Energy Technology Data Exchange (ETDEWEB)

    Buyevich, Yu A

    1974-01-01

    Stationary heat transfer in a granular material consisting of a continuous medium containing spherical granules of other substances is considered under the assumption that the spatial distribution of granules is random. The effective thermal conductivity characterizing macroscopic heat transfer in such a material is expressed as a certain function of the conductivities and volume fractions of the medium and dispersed substances. For reasons of mathematical analogy, all the results obtained for the thermal conductivity are valid while computing the effective diffusivity of some admixture in granular materials as well as for evaluation of the effective electric conductivity or the mean dielectric and magnetic permeabilities of granular conductors and dielectrics. (23 refs.)

  1. Effective temperature and fluctuation-dissipation theorem in athermal granular systems: A review

    International Nuclear Information System (INIS)

    Chen Qiong; Hou Mei-Ying

    2014-01-01

    The definition and the previous measurements of a dynamics-relevant temperature-like quantity in granular media are reviewed for slow and fast particle systems. Especially, the validity of the fluctuation-dissipation theorem in such an athermal system is explored. Experimental evidences for the fluctuation-dissipation theorem relevant effect temperature support the athermal statistical mechanics, which has been widely explored in recent years by physicists. Difficulties encountered in defining temperature or establishing thermodynamics or statistical mechanics in non-equilibrium situations are discussed. (topical review - statistical physics and complex systems)

  2. Teaching English through Mass Media

    Science.gov (United States)

    Tafani, Vilma

    2009-01-01

    This article aims at analyzing the importance of using Mass Media in the classroom and finding the ways how to use Printed and Audio-visual Media. It is the result of an in-depth study, surveys and questionnaires thus trying to make the ideas in this article more trustworthy. It is based not only on the literature review but also on long personal…

  3. Granular materials flow like complex fluids

    Science.gov (United States)

    Kou, Binquan; Cao, Yixin; Li, Jindong; Xia, Chengjie; Li, Zhifeng; Dong, Haipeng; Zhang, Ang; Zhang, Jie; Kob, Walter; Wang, Yujie

    2017-11-01

    Granular materials such as sand, powders and foams are ubiquitous in daily life and in industrial and geotechnical applications. These disordered systems form stable structures when unperturbed, but in the presence of external influences such as tapping or shear they `relax', becoming fluid in nature. It is often assumed that the relaxation dynamics of granular systems is similar to that of thermal glass-forming systems. However, so far it has not been possible to determine experimentally the dynamic properties of three-dimensional granular systems at the particle level. This lack of experimental data, combined with the fact that the motion of granular particles involves friction (whereas the motion of particles in thermal glass-forming systems does not), means that an accurate description of the relaxation dynamics of granular materials is lacking. Here we use X-ray tomography to determine the microscale relaxation dynamics of hard granular ellipsoids subject to an oscillatory shear. We find that the distribution of the displacements of the ellipsoids is well described by a Gumbel law (which is similar to a Gaussian distribution for small displacements but has a heavier tail for larger displacements), with a shape parameter that is independent of the amplitude of the shear strain and of the time. Despite this universality, the mean squared displacement of an individual ellipsoid follows a power law as a function of time, with an exponent that does depend on the strain amplitude and time. We argue that these results are related to microscale relaxation mechanisms that involve friction and memory effects (whereby the motion of an ellipsoid at a given point in time depends on its previous motion). Our observations demonstrate that, at the particle level, the dynamic behaviour of granular systems is qualitatively different from that of thermal glass-forming systems, and is instead more similar to that of complex fluids. We conclude that granular materials can relax

  4. A constitutive law for dense granular flows.

    Science.gov (United States)

    Jop, Pierre; Forterre, Yoël; Pouliquen, Olivier

    2006-06-08

    A continuum description of granular flows would be of considerable help in predicting natural geophysical hazards or in designing industrial processes. However, the constitutive equations for dry granular flows, which govern how the material moves under shear, are still a matter of debate. One difficulty is that grains can behave like a solid (in a sand pile), a liquid (when poured from a silo) or a gas (when strongly agitated). For the two extreme regimes, constitutive equations have been proposed based on kinetic theory for collisional rapid flows, and soil mechanics for slow plastic flows. However, the intermediate dense regime, where the granular material flows like a liquid, still lacks a unified view and has motivated many studies over the past decade. The main characteristics of granular liquids are: a yield criterion (a critical shear stress below which flow is not possible) and a complex dependence on shear rate when flowing. In this sense, granular matter shares similarities with classical visco-plastic fluids such as Bingham fluids. Here we propose a new constitutive relation for dense granular flows, inspired by this analogy and recent numerical and experimental work. We then test our three-dimensional (3D) model through experiments on granular flows on a pile between rough sidewalls, in which a complex 3D flow pattern develops. We show that, without any fitting parameter, the model gives quantitative predictions for the flow shape and velocity profiles. Our results support the idea that a simple visco-plastic approach can quantitatively capture granular flow properties, and could serve as a basic tool for modelling more complex flows in geophysical or industrial applications.

  5. Flow above and within granular media composed of spherical and non-spherical particles - using a 3D numerical model

    Science.gov (United States)

    Bartzke, Gerhard; Kuhlmann, Jannis; Huhn, Katrin

    2016-04-01

    The entrainment of single grains and, hence, their erosion characteristics are dependent on fluid forcing, grain size and density, but also shape variations. To quantitatively describe and capture the hydrodynamic conditions around individual grains, researchers commonly use empirical approaches such as laboratory flume tanks. Nonetheless, it is difficult with such physical experiments to measure the flow velocities in the direct vicinity or within the pore spaces of sediments, at a sufficient resolution and in a non-invasive way. As a result, the hydrodynamic conditions in the water column, at the fluid-porous interface and within pore spaces of a granular medium of various grain shapes is not yet fully understood. For that reason, there is a strong need for numerical models, since these are capable of quantifying fluid speeds within a granular medium. A 3D-SPH (Smooth Particle Hydrodynamics) numerical wave tank model was set up to provide quantitative evidence on the flow velocities in the direct vicinity and in the interior of granular beds composed of two shapes as a complementary method to the difficult task of in situ measurement. On the basis of previous successful numerical wave tank models with SPH, the model geometry was chosen in dimensions of X=2.68 [m], Y=0.48 [m], and Z=0.8 [m]. Three suites of experiments were designed with a range of particle shape models: (1) ellipsoids with the long axis oriented in the across-stream direction, (2) ellipsoids with the long axis oriented in the along-stream direction, and (3) spheres. Particle diameters ranged from 0.04 [m] to 0.08 [m]. A wave was introduced by a vertical paddle that accelerated to 0.8 [m/s] perpendicular to the granular bed. Flow measurements showed that the flow velocity values into the beds were highest when the grains were oriented across the stream direction and lowest in case when the grains were oriented parallel to the stream, indicating that the model was capable to simulate simultaneously

  6. Media Education: Sociology Surveys

    Science.gov (United States)

    Fedorov, Alexander

    2007-01-01

    In Russia as well as in foreign countries we can witness sort of the confusion of the terms of "media education" and "media literacy". There are quite a few differences in theoretical approaches to media education, to distinguishing of the most important aims, objectives, means of introduction into the teaching process, etc.…

  7. Magnetic properties of soft layer/FePt-MgO exchange coupled composite Perpendicular recording media

    Institute of Scientific and Technical Information of China (English)

    Yin Jin-Hua; Takao Suzuki; Pan Li-Qing

    2008-01-01

    The magnetic properties of exchange coupled composite(ECC)media that are composed of perpendicular magnetic recording media FePt-MgO and two kinds of soft layers have been studied by using an x-ray diffractometer,a polar Kerr magneto-optical system(PMOKE)and a vibrating sample magnetometer(VSM).The results show that ECC media can reduce the coercivities of perpendicular magnetic recording media FePt-MgO.The ECC media with granular-type soft layers have weaker exchange couplings between magnetic grains and the magnetization process,for ECC media of this kind mainly follow the Stoner-Wohlfarth model.

  8. Evaluation of granular anaerobic ammonium oxidation process for the disposal of pre-treated swine manure

    OpenAIRE

    Shou-Qing Ni; Ning Yang

    2014-01-01

    With rising environmental concerns on potable water safety and eutrophication, increased media attention and tighter environmental regulations, managing animal waste in an environmentally responsible and economically feasible way can be a challenge. In this study, the possibility of using granular anammox process for ammonia removal from swine waste treatment water was investigated. A rapid decrease of NO2 −–N and NH4 +–N was observed during incubation with wastewater from an activated sludge...

  9. PENGGUNAAN MEDIA GRAFIS DALAM PROSES PEMBELAJARAN

    Directory of Open Access Journals (Sweden)

    Safei Safei

    2007-06-01

    Full Text Available The existence of teacher in educational sector is very important, because, the teacher is one of components instructional system which decides educational quality in the future. In teaching learning process, a teacher is demanded to do the instruction effec-tively and efficiently. Therefore, the use of graphic media in becomes a solution in teaching learning process with verbal teaching in the classroom. By using graphic media in teaching learning process can increase the learner interest and attention and it can also make clear the material is presented. It is very simple and easy to make it relatively cheaper. Besides that, it can help the teacher in teaching and learning process in order to help the leaner to study.

  10. Status of Utilizing Social Media Networks in the Teaching-Learning Process at Public Jordanian Universities

    OpenAIRE

    Muneera Abdalkareem Alshdefait; Mohammad . S. Alzboon

    2018-01-01

    This study aimed at finding out the status of utilizing social media networks in the teaching-learning process at public Jordanian Universities. To achieve the goal of the study, the descriptive developmental method was used and a questionnaire was developed, consisting of (35) statements. The questionnaire was checked for its validity and reliability. Then it was distributed to a sample of (382) male and female students from the undergraduate and graduate levels. The study results showed tha...

  11. DEM simulation of granular flows in a centrifugal acceleration field

    Science.gov (United States)

    Cabrera, Miguel Angel; Peng, Chong; Wu, Wei

    2017-04-01

    The main purpose of mass-flow experimental models is abstracting distinctive features of natural granular flows, and allow its systematic study in the laboratory. In this process, particle size, space, time, and stress scales must be considered for the proper representation of specific phenomena [5]. One of the most challenging tasks in small scale models, is matching the range of stresses and strains among the particle and fluid media observed in a field event. Centrifuge modelling offers an alternative to upscale all gravity-driven processes, and it has been recently employed in the simulation of granular flows [1, 2, 3, 6, 7]. Centrifuge scaling principles are presented in Ref. [4], collecting a wide spectrum of static and dynamic models. However, for the case of kinematic processes, the non-uniformity of the centrifugal acceleration field plays a major role (i.e., Coriolis and inertial effects). In this work, we discuss a general formulation for the centrifugal acceleration field, implemented in a discrete element model framework (DEM), and validated with centrifuge experimental results. Conventional DEM simulations relate the volumetric forces as a function of the gravitational force Gp = mpg. However, in the local coordinate system of a rotating centrifuge model, the cylindrical centrifugal acceleration field needs to be included. In this rotating system, the centrifugal acceleration of a particle depends on the rotating speed of the centrifuge, as well as the position and speed of the particle in the rotating model. Therefore, we obtain the formulation of centrifugal acceleration field by coordinate transformation. The numerical model is validated with a series of centrifuge experiments of monodispersed glass beads, flowing down an inclined plane at different acceleration levels and slope angles. Further discussion leads to the numerical parameterization necessary for simulating equivalent granular flows under an augmented acceleration field. The premise of

  12. Systematic description of the effect of particle shape on the strength properties of granular media

    Directory of Open Access Journals (Sweden)

    Azéma Emilien

    2017-01-01

    Full Text Available In this paper, we explore numerically the effect of particle shape on the mechanical behavior of sheared granular packings. In the framework of the Contact Dynamic (CDMethod, we model angular shape as irregular polyhedral particles, non-convex shape as regular aggregates of four overlapping spheres, elongated shape as rounded cap rectangles and platy shape as square-plates. Binary granular mixture consisting of disks and elongated particles are also considered. For each above situations, the number of face of polyhedral particles, the overlap of spheres, the aspect ratio of elongated and platy particles, are systematically varied from spheres to very angular, non-convex, elongated and platy shapes. The level of homogeneity of binary mixture varies from homogenous packing to fully segregated packings. Our numerical results suggest that the effects of shape parameters are nonlinear and counterintuitive. We show that the shear strength increases as shape deviate from spherical shape. But, for angular shapes it first increases up to a maximum value and then saturates to a constant value as the particles become more angular. For mixture of two shapes, the strength increases with respect of the increase of the proportion of elongated particles, but surprisingly it is independent with the level of homogeneity of the mixture. A detailed analysis of the contact network topology, evidence that various contact types contribute differently to stress transmission at the micro-scale.

  13. Penggunaan Media Visual dalam Proses Pembelajaran

    Directory of Open Access Journals (Sweden)

    Haris Budiman

    2017-08-01

    Full Text Available Conventional teaching and learning process it has many shortcomings, which are caused by not all teachers have the same competence, differences in absorption of learners in listening to lessons, teaching materials that teachers have limited and learning activities for students as objects tend to be boring.                For that teachers are required to have creativity in teaching, teachers are required able to stimulate learners to be proactive in learning activities. Like a bridge connecting the two sides, the role played by media learning in a teaching system. That role becomes vital for visual learning media is not only responsible for the arrival of a message to student learning, but also ensures that the message does not degrade or irregularities meaning. Thus a learning process by using visual media can boost creativity and motivation for learners to learn and can be done effectively and efficiently.

  14. Substructural Regularization With Data-Sensitive Granularity for Sequence Transfer Learning.

    Science.gov (United States)

    Sun, Shichang; Liu, Hongbo; Meng, Jiana; Chen, C L Philip; Yang, Yu

    2018-06-01

    Sequence transfer learning is of interest in both academia and industry with the emergence of numerous new text domains from Twitter and other social media tools. In this paper, we put forward the data-sensitive granularity for transfer learning, and then, a novel substructural regularization transfer learning model (STLM) is proposed to preserve target domain features at substructural granularity in the light of the condition of labeled data set size. Our model is underpinned by hidden Markov model and regularization theory, where the substructural representation can be integrated as a penalty after measuring the dissimilarity of substructures between target domain and STLM with relative entropy. STLM can achieve the competing goals of preserving the target domain substructure and utilizing the observations from both the target and source domains simultaneously. The estimation of STLM is very efficient since an analytical solution can be derived as a necessary and sufficient condition. The relative usability of substructures to act as regularization parameters and the time complexity of STLM are also analyzed and discussed. Comprehensive experiments of part-of-speech tagging with both Brown and Twitter corpora fully justify that our model can make improvements on all the combinations of source and target domains.

  15. HYPERELASTIC MODELS FOR GRANULAR MATERIALS

    Energy Technology Data Exchange (ETDEWEB)

    Humrickhouse, Paul W; Corradini, Michael L

    2009-01-29

    A continuum framework for modeling of dust mobilization and transport, and the behavior of granular systems in general, has been reviewed, developed and evaluated for reactor design applications. The large quantities of micron-sized particles expected in the international fusion reactor design, ITER, will accumulate into piles and layers on surfaces, which are large relative to the individual particle size; thus, particle-particle, rather than particle-surface, interactions will determine the behavior of the material in bulk, and a continuum approach is necessary and justified in treating the phenomena of interest; e.g., particle resuspension and transport. The various constitutive relations that characterize these solid particle interactions in dense granular flows have been discussed previously, but prior to mobilization their behavior is not even fluid. Even in the absence of adhesive forces between particles, dust or sand piles can exist in static equilibrium under gravity and other forces, e.g., fluid shear. Their behavior is understood to be elastic, though not linear. The recent “granular elasticity” theory proposes a non-linear elastic model based on “Hertz contacts” between particles; the theory identifies the Coulomb yield condition as a requirement for thermodynamic stability, and has successfully reproduced experimental results for stress distributions in sand piles. The granular elasticity theory is developed and implemented in a stand- alone model and then implemented as part of a finite element model, ABAQUS, to determine the stress distributions in dust piles subjected to shear by a fluid flow. We identify yield with the onset of mobilization, and establish, for a given dust pile and flow geometry, the threshold pressure (force) conditions on the surface due to flow required to initiate it. While the granular elasticity theory applies strictly to cohesionless granular materials, attractive forces are clearly important in the interaction of

  16. Classroom strategies in teaching the media

    Directory of Open Access Journals (Sweden)

    Reijo Kupiainen

    2015-11-01

    Full Text Available Th is article is based on Chapter 5 of my book Media and Digital Literacies in Secondary School (2013. The chapter has been shortened and rewritten in some parts for the article. The article focuses on different classroom strategies identified during the ethnographic school research in one of the Finnish secondary schools carried out during the academic year 2009–2010. The study indicates that teachers analyse and produce media texts as key strategies in media education. In the article, I will give examples of an advertisement project, a soap opera drama, an animation project, a "life career assignment" and a newspaper strategy in different learning settings. All examples indicate that media education needs to build a strong bridge between youth and school culture and that technology in the school follows the content of learning.

  17. NMR Measurements of Granular Flow and Compaction

    Science.gov (United States)

    Fukushima, Eiichi

    1998-03-01

    Nuclear magnetic resonance (NMR) can be used to measure statistical distributions of granular flow velocity and fluctuations of velocity, as well as spatial distributions of particulate concentration, flow velocity, its fluctuations, and other parameters that may be derived from these. All measurements have been of protons in liquid-containing particles such as mustard seeds or pharmaceutical pills. Our favorite geometry has been the slowly rotating partially filled rotating drum with granular flow taking place along the free surface of the particles. All the above-mentioned parameters have been studied as well as a spatial distribution of particulate diffusion coefficients, energy dissipation due to collisions, as well as segregation of non-uniform mixtures of granular material. Finally, we describe some motions of granular material under periodic vibrations.

  18. Flow and fracture in water-saturated, unconstrained granular beds

    Directory of Open Access Journals (Sweden)

    Germán eVaras

    2015-06-01

    Full Text Available The injection of gas in a liquid-saturated granular bed gives rise to a wide variety of invasion patterns. Many studies have focused on constrained porous media, in which the grains are fixed in the bed and only the interstitial fluid flows when the gas invades the system. With a free upper boundary, however, the grains can be entrained by the ascending gas or fluid motion, and the competition between the upward motion of grains and sedimentation leads to new patterns. We propose a brief review of the experimental investigation of the dynamics of air rising through a water-saturated, unconstrained granular bed, in both two and three dimensions. After describing the invasion pattern at short and long time, a tentative regime-diagram is proposed. We report original results showing a dependence of the fluidized zone shape, at long times, on the injection flow rate and grain size. A method based on image analysis makes it possible to detect not only the fluidized zone profile in the stationary regime, but also to follow the transient dynamics of its formation. Finally, we describe the degassing dynamics inside the fluidized zone, in the stationary regime. Depending on the experimental conditions, regular bubbling, continuous degassing, intermittent regime or even spontaneous flow-to-fracture transition are observed.

  19. Impact of granular drops

    KAUST Repository

    Marston, J. O.

    2013-07-15

    We investigate the spreading and splashing of granular drops during impact with a solid target. The granular drops are formed from roughly spherical balls of sand mixed with water, which is used as a binder to hold the ball together during free-fall. We measure the instantaneous spread diameter for different impact speeds and find that the normalized spread diameter d/D grows as (tV/D)1/2. The speeds of the grains ejected during the “splash” are measured and they rarely exceed twice that of the impact speed.

  20. Impact of granular drops

    KAUST Repository

    Marston, J. O.; Mansoor, Mohammad M.; Thoroddsen, Sigurdur T

    2013-01-01

    We investigate the spreading and splashing of granular drops during impact with a solid target. The granular drops are formed from roughly spherical balls of sand mixed with water, which is used as a binder to hold the ball together during free-fall. We measure the instantaneous spread diameter for different impact speeds and find that the normalized spread diameter d/D grows as (tV/D)1/2. The speeds of the grains ejected during the “splash” are measured and they rarely exceed twice that of the impact speed.

  1. Viscosity evolution of anaerobic granular sludge

    NARCIS (Netherlands)

    Pevere, A.; Guibaud, G.; Hullebusch, van E.D.; Lens, P.N.L.; Baudu, M.

    2006-01-01

    The evolution of the apparent viscosity at steady shear rate of sieved anaerobic granular sludge (20¿315 ¿m diameter) sampled from different full-scale anaerobic reactors was recorded using rotation tests. The ¿limit viscosity¿ of sieved anaerobic granular sludge was determined from the apparent

  2. PENGGUNAAN MEDIA PEMBELAJARAN MICROSOFT OFFICE POWERPOINT PADA POKOK BAHASAN PELUANG

    Directory of Open Access Journals (Sweden)

    author Rahma Faelasofi

    2015-01-01

    Full Text Available The objectives of this research was to solve how to increase the students’ average result especially on the subject of Opportunities. This study aims to determine whether the students’ average result of the student Mathematic Education Department STKIP Muhammadiyah Pringsewu Lampung (STKIP MPL in the academic year of 2013-2014 using instructional teaching media using Microsoft Office PowerPoint on the subject of Opportunities, is better than the students’ average result without using instructional teaching media using Microsoft Office PowerPoint. This research is a quantitative approach, with a quasi-experimental research methods. The population was all of the students in third grade of the Mathematic Education Department STKIP MPL in the academic year of 2013-2014. The samples of the research were taken by using the cluster random sampling technique. Based on hypothesis test, it can be included that: 1 there are differences in students’ average results between experiment class that used computer teaching media using Microsoft Office PowerPoint and the kontrol class without using a computer teaching media using Microsoft Office PowerPoint; 2 the students’ average results at experiment class that used a computer teaching media using Microsoft Office PowerPoint higher than the students’ average results in kontrol class.Keywords: Teaching Media, Microsoft Office PowerPoint, Subject of Opportunities

  3. Social Media Tools for Teaching and Learning

    Science.gov (United States)

    Wagner, Ronald

    2011-01-01

    According to Wikipedia, "social media is the media designed to be disseminated through social interaction, created using highly accessible scalable techniques. Social media is the use of web-based and mobile technologies to turn communication into interactive dialogue." Social networks, such as Facebook and Twitter, contain millions of members who…

  4. Critical phenomenon of granular flow on a conveyor belt.

    Science.gov (United States)

    De-Song, Bao; Xun-Sheng, Zhang; Guang-Lei, Xu; Zheng-Quan, Pan; Xiao-Wei, Tang; Kun-Quan, Lu

    2003-06-01

    The relationship between the granular wafer movement on a two-dimensional conveyor belt and the size of the exit together with the velocity of the conveyor belt has been studied in the experiment. The result shows that there is a critical speed v(c) for the granular flow when the exit width d is fixed (where d=R/D, D being the diameter of a granular wafers). When vv(c), the flow rate Q is described as Q=Crho(v)(beta)(d-k)(3/2). These are the effects of the interaction among the granular wafers and the change of the states of the granular flow due to the changing of the speed or the exit width d.

  5. Survivable integrated grooming in multi-granularity optical networks

    Science.gov (United States)

    Wu, Jingjing; Guo, Lei; Wei, Xuetao; Liu, Yejun

    2012-05-01

    Survivability is an important issue to ensure the service continuity in optical network. At the same time, with the granularity of traffic demands ranging from sub-wavelength-level to wavelength-level, traffic demands need to be aggregated and carried over the network in order to utilize resources effectively. Therefore, multi-granularity grooming is proposed to save the cost and reduce the number of switching ports in Optical-Cross Connects (OXCs). However, current works mostly addressed the survivable wavelength or waveband grooming. Therefore, in this paper, we propose three heuristic algorithms called Multi-granularity Dedicated Protection Grooming (MDPG), Multi-granularity Shared Protection Grooming (MSPG) and Multi-granularity Mixed Protection Grooming (MMPG), respectively. All of them are performed based on the Survivable Multi-granularity Integrated Auxiliary Graph (SMIAG) that includes one Wavelength Integrated Auxiliary Graph (WIAG) for wavelength protection and one waveBand Integrated Auxiliary Graph (BIAG) for waveband protection. Numerical results show that MMPG has the lowest average port-cost, the best resource utilization ratio and the lowest blocking probability among these three algorithms. Compared with MDPG, MSPG has lower average port-cost, better resource utilization ratio and lower blocking probability.

  6. Superconductivity in inhomogeneous granular metals

    International Nuclear Information System (INIS)

    McLean, W.L.

    1980-01-01

    A model of elongated metal ellipsoids imbedded in a granular metal is treated by an effective medium approach to explain the observed temperature dependence of the normal-state conductivity of superconducting granular aluminum. Josephson tunneling is thus still required to account for the superconductivity. The model predicts the same kind of contrasting behavior on opposite sides of the metal-insulator transition as is found in the recent scaling treatment of Anderson localization

  7. Approaches to Learning with Media and Media Literacy Education--Trends and Current Situation in Germany

    Science.gov (United States)

    Tulodziecki, Gerhard; Grafe, Silke

    2012-01-01

    German approaches to media literacy education are concerned with the questions, how the variety of media can be used in a meaningful way for learning and teaching and what educational tasks result from the extensive use of media. Considering these questions there are various conceptual ideas, research and development projects as well as…

  8. Thermal conductivity of granular porous media: A pore scale modeling approach

    Directory of Open Access Journals (Sweden)

    R. Askari

    2015-09-01

    Full Text Available Pore scale modeling method has been widely used in the petrophysical studies to estimate macroscopic properties (e.g. porosity, permeability, and electrical resistivity of porous media with respect to their micro structures. Although there is a sumptuous literature about the application of the method to study flow in porous media, there are fewer studies regarding its application to thermal conduction characterization, and the estimation of effective thermal conductivity, which is a salient parameter in many engineering surveys (e.g. geothermal resources and heavy oil recovery. By considering thermal contact resistance, we demonstrate the robustness of the method for predicting the effective thermal conductivity. According to our results obtained from Utah oil sand samples simulations, the simulation of thermal contact resistance is pivotal to grant reliable estimates of effective thermal conductivity. Our estimated effective thermal conductivities exhibit a better compatibility with the experimental data in companion with some famous experimental and analytical equations for the calculation of the effective thermal conductivity. In addition, we reconstruct a porous medium for an Alberta oil sand sample. By increasing roughness, we observe the effect of thermal contact resistance in the decrease of the effective thermal conductivity. However, the roughness effect becomes more noticeable when there is a higher thermal conductivity of solid to fluid ratio. Moreover, by considering the thermal resistance in porous media with different grains sizes, we find that the effective thermal conductivity augments with increased grain size. Our observation is in a reasonable accordance with experimental results. This demonstrates the usefulness of our modeling approach for further computational studies of heat transfer in porous media.

  9. INVESTIGATION OF INNER SHEAR RESISTANCE OF GEOGRIDS BUILT UNDER GRANULAR PROTECTION LAYERS AND RAILWAY BALLAST

    Directory of Open Access Journals (Sweden)

    Sz. Fischer

    2015-10-01

    Full Text Available Purpose. Using adequate granular materials and layer structures in the railway super- and substructure is able to stabilise railway track geometry. For this purpose special behaviour of above materials has to be determined, e.g. inner shear resistance. Inner shear resistance of granular media with and without geogrid reinforcement in different depths is not known yet. Methodology. The author developed a special laboratory method to measure and define inner shear resistance of granular materials, it is called «multi-level shear box test». This method is adequate to determine inner shear resistance (pushing force vs. depth (distance from the «zero» surface. Two different granular materials: andesite railway ballast (31.5/63 mm and andesite railway protection layer material (0/56 mm, and seven different types of geogrids (GG1…GG7 were used during the tests. Findings. Values of inner shear resistance functions of andesite railway ballast without geogrid reinforcement and reinforced with different types of geogrids and andesite granular protection layer in function of the vertical distance from the geogrid plane were determined with multi-layer shear box tests when the material aggregation is uncompacted and compacted. Only the compacted sample was tested in case of the 0/56 mm protection layer. Cubic polynomial regression functions fitted on the mean values of the measurements are described graphically. Determination coefficients with values of R2>0.97 were resulted in all the cases of regression functions. Based on the polynomial regression functions fitted on the mean values of the test results, three increasing factors were determined in function of the distance measured from the geogrid. Increasing factor «A», «B» and «D». Originality. Multi-level shear box test, developed by the author, is certified unequivocally adequate for determining inner shear resistance of reinforced and unreinforced granular materials, e.g. railway ballast

  10. Penetration in bimodal, polydisperse granular material

    KAUST Repository

    Kouraytem, Nadia; Thoroddsen, Sigurdur T; Marston, J. O.

    2016-01-01

    We investigate the impact penetration of spheres into granular media which are compositions of two discrete size ranges, thus creating a polydisperse bimodal material. We examine the penetration depth as a function of the composition (volume fractions of the respective sizes) and impact speed. Penetration depths were found to vary between delta = 0.5D(0) and delta = 7D(0), which, for mono-modal media only, could be correlated in terms of the total drop height, H = h + delta, as in previous studies, by incorporating correction factors for the packing fraction. Bimodal data can only be collapsed by deriving a critical packing fraction for each mass fraction. The data for the mixed grains exhibit a surprising lubricating effect, which was most significant when the finest grains [d(s) similar to O(30) mu m] were added to the larger particles [d(l) similar to O(200 - 500) mu m], with a size ratio, epsilon = d(l)/d(s), larger than 3 and mass fractions over 25%, despite the increased packing fraction. We postulate that the small grains get between the large grains and reduce their intergrain friction, only when their mass fraction is sufficiently large to prevent them from simply rattling in the voids between the large particles. This is supported by our experimental observations of the largest lubrication effect produced by adding small glass beads to a bed of large sand particles with rough surfaces.

  11. Penetration in bimodal, polydisperse granular material

    KAUST Repository

    Kouraytem, N.

    2016-11-07

    We investigate the impact penetration of spheres into granular media which are compositions of two discrete size ranges, thus creating a polydisperse bimodal material. We examine the penetration depth as a function of the composition (volume fractions of the respective sizes) and impact speed. Penetration depths were found to vary between delta = 0.5D(0) and delta = 7D(0), which, for mono-modal media only, could be correlated in terms of the total drop height, H = h + delta, as in previous studies, by incorporating correction factors for the packing fraction. Bimodal data can only be collapsed by deriving a critical packing fraction for each mass fraction. The data for the mixed grains exhibit a surprising lubricating effect, which was most significant when the finest grains [d(s) similar to O(30) mu m] were added to the larger particles [d(l) similar to O(200 - 500) mu m], with a size ratio, epsilon = d(l)/d(s), larger than 3 and mass fractions over 25%, despite the increased packing fraction. We postulate that the small grains get between the large grains and reduce their intergrain friction, only when their mass fraction is sufficiently large to prevent them from simply rattling in the voids between the large particles. This is supported by our experimental observations of the largest lubrication effect produced by adding small glass beads to a bed of large sand particles with rough surfaces.

  12. Nonlinear coherent structures in granular crystals

    Science.gov (United States)

    Chong, C.; Porter, Mason A.; Kevrekidis, P. G.; Daraio, C.

    2017-10-01

    The study of granular crystals, which are nonlinear metamaterials that consist of closely packed arrays of particles that interact elastically, is a vibrant area of research that combines ideas from disciplines such as materials science, nonlinear dynamics, and condensed-matter physics. Granular crystals exploit geometrical nonlinearities in their constitutive microstructure to produce properties (such as tunability and energy localization) that are not conventional to engineering materials and linear devices. In this topical review, we focus on recent experimental, computational, and theoretical results on nonlinear coherent structures in granular crystals. Such structures—which include traveling solitary waves, dispersive shock waves, and discrete breathers—have fascinating dynamics, including a diversity of both transient features and robust, long-lived patterns that emerge from broad classes of initial data. In our review, we primarily discuss phenomena in one-dimensional crystals, as most research to date has focused on such scenarios, but we also present some extensions to two-dimensional settings. Throughout the review, we highlight open problems and discuss a variety of potential engineering applications that arise from the rich dynamic response of granular crystals.

  13. On inconsistency in frictional granular systems

    Science.gov (United States)

    Alart, Pierre; Renouf, Mathieu

    2018-04-01

    Numerical simulation of granular systems is often based on a discrete element method. The nonsmooth contact dynamics approach can be used to solve a broad range of granular problems, especially involving rigid bodies. However, difficulties could be encountered and hamper successful completion of some simulations. The slow convergence of the nonsmooth solver may sometimes be attributed to an ill-conditioned system, but the convergence may also fail. The prime aim of the present study was to identify situations that hamper the consistency of the mathematical problem to solve. Some simple granular systems were investigated in detail while reviewing and applying the related theoretical results. A practical alternative is briefly analyzed and tested.

  14. Storage and discharge of a granular fluid.

    Science.gov (United States)

    Pacheco-Martinez, Hector; van Gerner, Henk Jan; Ruiz-Suárez, J C

    2008-02-01

    Experiments and computational simulations are carried out to study the behavior of a granular column in a silo whose walls are able to vibrate horizontally. The column is brought to a steady fluidized state and it behaves similar to a hydrostatic system. We study the dynamics of the granular discharge through openings at the bottom of the silo in order to search for a Torricelli-like behavior. We show that the flow rate scales with the wall induced shear rate, and at high rates, the granular bed indeed discharges similar to a viscous fluid.

  15. Characterization of Unbound Granular Materials for Pavements

    NARCIS (Netherlands)

    Araya, A.A.

    2011-01-01

    This research is focused on the characterization of the mechanical behavior of unbound granular road base materials (UGMs). An extensive laboratory investigation is described, in which various methods for determination of the mechanical properties of granular materials are examined for their

  16. A numerical study of granular dam-break flow

    Science.gov (United States)

    Pophet, N.; Rébillout, L.; Ozeren, Y.; Altinakar, M.

    2017-12-01

    Accurate prediction of granular flow behavior is essential to optimize mitigation measures for hazardous natural granular flows such as landslides, debris flows and tailings-dam break flows. So far, most successful models for these types of flows focus on either pure granular flows or flows of saturated grain-fluid mixtures by employing a constant friction model or more complex rheological models. These saturated models often produce non-physical result when they are applied to simulate flows of partially saturated mixtures. Therefore, more advanced models are needed. A numerical model was developed for granular flow employing a constant friction and μ(I) rheology (Jop et al., J. Fluid Mech. 2005) coupled with a groundwater flow model for seepage flow. The granular flow is simulated by solving a mixture model using Finite Volume Method (FVM). The Volume-of-Fluid (VOF) technique is used to capture the free surface motion. The constant friction and μ(I) rheological models are incorporated in the mixture model. The seepage flow is modeled by solving Richards equation. A framework is developed to couple these two solvers in OpenFOAM. The model was validated and tested by reproducing laboratory experiments of partially and fully channelized dam-break flows of dry and initially saturated granular material. To obtain appropriate parameters for rheological models, a series of simulations with different sets of rheological parameters is performed. The simulation results obtained from constant friction and μ(I) rheological models are compared with laboratory experiments for granular free surface interface, front position and velocity field during the flows. The numerical predictions indicate that the proposed model is promising in predicting dynamics of the flow and deposition process. The proposed model may provide more reliable insight than the previous assumed saturated mixture model, when saturated and partially saturated portions of granular mixture co-exist.

  17. Teaching Sexuality through Media

    Science.gov (United States)

    Cragin, Becca

    2015-01-01

    A central project of feminism has been raising awareness of the role cultural formations of sexuality play in women's inequality (Ritzenhoff and Hermes). Feminists who regularly include discussions of sexuality in their teaching are familiar with the pedagogical challenges of the subject as well as its importance. This article is intended for…

  18. Transport of ARS-labeled hydroxyapatite nanoparticles in saturated granular media is influenced by surface charge variability even in the presence of humic acid

    Science.gov (United States)

    Wang, Dengjun; Bradford, Scott A.; Harvey, Ronald W.; Hao, Xiuzhen; Zhou, Dongmei

    2012-01-01

    Hydroxyapatite nanoparticle (nHAP) is increasingly being used to remediate soils and water polluted by metals and radionuclides. The transport and retention of Alizarin red S (ARS)-labeled nHAP were investigated in water-saturated granular media. Experiments were carried out over a range of ionic strength (Ic, 0–50 mM NaCl) conditions in the presence of 10 mg L−1 humic acid. The transport of ARS-nHAP was found to decrease with increasing suspension Ic in part, because of enhanced aggregation and chemical heterogeneity. The retention profiles (RPs) of ARS-nHAP exhibited hyperexponential shapes (a decreasing rate of retention with increasing transport distance) for all test conditions, suggesting that some of the attachment was occurring under unfavorable conditions. Surface charge heterogeneities on the collector surfaces and especially within the ARS-nHAP population were contributing causes for the hyperexponential RPs. Consideration of the effect(s) of Ic in the presence of HA is needed to improve the efficacy of nHAP for scavenging metals and actinides in real soils and groundwater environments.

  19. Komik Pendidikan sebagai Media Inofatif MI/SD

    Directory of Open Access Journals (Sweden)

    Sigit Dwi Laksana

    2015-11-01

    Full Text Available As a teaching media, a picture in a comic means thousand words. Edward Lee Thorndike conducts a research on the benefit of using comic for learning and the results shows that using comic is effective in improving learners’ mastery of vocabulary. As a teaching media, educational comics which are specially designed for educational purpose are effective to help low motivated learners.

  20. The Perceptions of Primary School Teachers and Teacher Candidates towards the Use of Mass Media in Teaching Turkish Language

    Science.gov (United States)

    Karadag, Ruhan

    2014-01-01

    The aim of the study is to explore the perceptions of primary school teachers and teacher candidates of the use of mass media in teaching Turkish in primary education. The data for this descriptive study is collected via semi-structured interviews--one of the qualitative data analysis methods and the collected data is analyzed by employing…

  1. Axial segregation of granular media rotated in a drum mixer: Pattern evolution

    International Nuclear Information System (INIS)

    Hill, K.M.; Kakalios, J.; Caprihan, A.

    1997-01-01

    In the traditional axial segregation effect, a homogeneous mixture of different types of granular material rotated in a drum mixer segregates into surface bands of relatively pure single concentrations along the axis of rotation. This effect primarily has been studied with respect to the initial segregation. However, the initial pattern is not stable, but evolves in time with continued rotation through metastable states of fewer and fewer bands. We describe two experimental studies of this evolution that provide a more complete picture of the dynamics involved in the pattern progression. The use of a charge coupled device camera in conjunction with digital analysis techniques provides a quantitative measure of the state of the surface as a function of time, while magnetic resonance imaging techniques provide a noninvasive method for studying the segregation beneath the surface. These methods indicate that the underlying mechanisms for the pattern evolution may originate in the bulk of the material, beneath the avalanching surface. copyright 1997 The American Physical Society

  2. Social media in nursing education: responsible integration for meaningful use.

    Science.gov (United States)

    Peck, Jessica L

    2014-03-01

    The astonishing popularity of social media and its emergence into the academic arena has shown tremendous potential for innovations in teaching. The appeal of using social media in the learning environment is enhanced by accessibility and affordability. However, it has also broadened the scope of consideration for protecting student privacy. This article explores the legal impact of privacy concerns when social media is used as a teaching tool. Institutions of higher learning must formulate guidelines that will govern appropriate social media use so that novel teaching modalities can be safely explored. Students must be educated by faculty regarding the standards of conduct and privacy considerations related to social media. The National Council of State Boards of Nursing has issued the White Paper: A Nurse's Guide to the Use of Social Media, a must-read for nursing faculty in the current academic arena. Copyright 2014, SLACK Incorporated.

  3. Granular Gases: Probing the Boundaries of Hydrodynamics

    International Nuclear Information System (INIS)

    Goldhirsch, I.

    1999-01-01

    The dissipative nature of the particle interactions in granular systems renders granular gases mesoscopic and bearing some similarities to regular gases in the ''continuum transition regime'' where shear rates and/or thermal gradients are very large). The following properties of granular gases support the above claim: (i). Mean free times are of the same order as macroscopic time scales (inverse shear rates); (ii). Mean free paths can be macroscopic and comparable to the system's dimensions; (iii). Typical flows are supersonic; (iv). Shear rates are typically ''large''; (v). Stress fields are scale (resolution) dependent; (vi). Burnett and super-Burnett corrections to both the constitutive relations and the boundary conditions are of importance; (vii). Single particle distribution functions can be far from Gaussian. It is concluded that while hydrodynamic descriptions of granular gases are relevant, they are probing the boundaries of applicability of hydrodynamics and perhaps slightly beyond

  4. Granular Silo collapse: an experimental study

    Science.gov (United States)

    Clement, Eric; Gutierriez, Gustavo; Boltenhagen, Philippe; Lanuza, Jose

    2008-03-01

    We present an experimental work that develop some basic insight into the pre-buckling behavior and the buckling transition toward plastic collapse of a granular silo. We study different patterns of deformation generated on thin paper cylindrical shells during granular discharge. We study the collapse threshold for different bed height, flow rates and grain sizes. We compare the patterns that appear during the discharge of spherical beads, with those obtained in the axially compressed cylindrical shells. When the height of the granular column is close to the collapse threshold, we describe a ladder like pattern that rises around the cylinder surface in a spiral path of diamond shaped localizations, and develops into a plastic collapsing fold that grows around the collapsing silo.

  5. Development of Approaches to Creation of Active Vibration Control System in Problems of the Dynamics for Granular Media

    Directory of Open Access Journals (Sweden)

    Khomenko Andrei P.

    2018-01-01

    Full Text Available The article deals with the development of mathematical models and evaluation criteria of the vibration field in the dynamic interactions of the elements of the vibrational technological machines for the processes of vibrational strengthening of long-length parts with help of a steel balls working medium. The study forms a theoretical understanding of the modes of motions of material particles in interaction with a vibrating surface of the working body of the vibration machine. The generalized approach to the assessment of the dynamic quality of the work of vibrating machines in multiple modes of tossing, when the period of free flight of particles is a multiple of the period of the surface oscillations of the working body, is developed in the article. For the correction of vibration field of the working body, the characteristics of dynamic interactions of granular elements of the medium are taken into account using original sensors. The sensors that can detect different particularities of interaction of the granular medium elements at different points of the working body are proposed to evaluate the deviation from a homogeneous and one-dimensional mode of vibration field. Specially developed sensors are able to register interactions between a single granule, a system of granules in filamentous structures, and multipoint interactions of the elements in a close-spaced cylindrical structure. The system of regularization of the structure of vibration fields based on the introduction of motion translation devices is proposed using the multi-point sensor locations on the working body. The article refers to analytical approaches of the theory of vibration displacements. For the experimental data assessment, the methods of statistical analysis are applied. It is shown that the peculiar features of the motion of granular medium registered by the sensors can be used to build active control systems of field vibration.

  6. A hydrodynamic model for granular material flows including segregation effects

    Science.gov (United States)

    Gilberg, Dominik; Klar, Axel; Steiner, Konrad

    2017-06-01

    The simulation of granular flows including segregation effects in large industrial processes using particle methods is accurate, but very time-consuming. To overcome the long computation times a macroscopic model is a natural choice. Therefore, we couple a mixture theory based segregation model to a hydrodynamic model of Navier-Stokes-type, describing the flow behavior of the granular material. The granular flow model is a hybrid model derived from kinetic theory and a soil mechanical approach to cover the regime of fast dilute flow, as well as slow dense flow, where the density of the granular material is close to the maximum packing density. Originally, the segregation model has been formulated by Thornton and Gray for idealized avalanches. It is modified and adapted to be in the preferred form for the coupling. In the final coupled model the segregation process depends on the local state of the granular system. On the other hand, the granular system changes as differently mixed regions of the granular material differ i.e. in the packing density. For the modeling process the focus lies on dry granular material flows of two particle types differing only in size but can be easily extended to arbitrary granular mixtures of different particle size and density. To solve the coupled system a finite volume approach is used. To test the model the rotational mixing of small and large particles in a tumbler is simulated.

  7. An Emotional Agent Model Based on Granular Computing

    Directory of Open Access Journals (Sweden)

    Jun Hu

    2012-01-01

    Full Text Available Affective computing has a very important significance for fulfilling intelligent information processing and harmonious communication between human being and computers. A new model for emotional agent is proposed in this paper to make agent have the ability of handling emotions, based on the granular computing theory and the traditional BDI agent model. Firstly, a new emotion knowledge base based on granular computing for emotion expression is presented in the model. Secondly, a new emotional reasoning algorithm based on granular computing is proposed. Thirdly, a new emotional agent model based on granular computing is presented. Finally, based on the model, an emotional agent for patient assistant in hospital is realized, experiment results show that it is efficient to handle simple emotions.

  8. Quantifying the Micromechanical Effects of Variable Cement in Granular Porous Media

    Energy Technology Data Exchange (ETDEWEB)

    Goodwin, Laurel B.; Boutt David F.

    2010-02-18

    The mechanical and hydrologic behavior of clastic rocks and sediments is fundamentally controlled by variables such as grain size and shape, sorting, grain and cement mineralogy, porosity, and %cement - parameters that are not used directly in field-scale models of coupled flow and deformation. To improve our understanding of the relationship between these micromechanical properties and bulk behavior we focused on (1) relating detailed, quantitative characterization of the grain-pore systems to both hydrologic and mechanical properties of a suite of variably quartz-cemented quartz arenite samples and (2) the use of a combination of discrete element method (DEM) and poroelastic models parameterized by data from the natural samples to isolate and compare the influence of changes in the mechanical and hydrologic properties of granular porous media due to changes in degree of cementation. Quartz overgrowths, the most common form of authigenic cements in sandstones, are responsible for significant porosity and permeability reduction. The distribution of quartz overgrowths is controlled by available pore space and the crystallographic orientations of individual quartz grains. Study of the St. Peter Sandstone allowed evaluation of the relative effects of quartz cementation and compaction on final grain and pore morphology, showing that progressive quartz cementation modifies the grain framework in consistent, predictable ways. Detailed microstructural characterization and multiple regression analyses show that with progressive diagenesis, the number and length of grain contacts increases as the number of pores increases, the number of large, well-connected pores decreases, and pores become rounder. These changes cause a decrease in pore size variability that leads to a decrease in bulk permeability and both stiffening and strengthening of the grain framework. The consistent nature of these changes allows us to predict variations in hydrologic and mechanical properties

  9. Assessing continuum postulates in simulations of granular flow

    Energy Technology Data Exchange (ETDEWEB)

    Rycroft, Chris; Kamrin, Ken; Bazant, Martin

    2008-08-26

    Continuum mechanics relies on the fundamental notion of a mesoscopic volume"element" in which properties averaged over discrete particles obey deterministic relationships. Recent work on granular materials suggests a continuum law may be inapplicable, revealing inhomogeneities at the particle level, such as force chains and slow cage breaking. Here, we analyze large-scale three-dimensional Discrete-Element Method (DEM) simulations of different granular flows and show that an approximate"granular element" defined at the scale of observed dynamical correlations (roughly three to five particle diameters) has a reasonable continuum interpretation. By viewing all the simulations as an ensemble of granular elements which deform and move with the flow, we can track material evolution at a local level. Our results confirm some of the hypotheses of classical plasticity theory while contradicting others and suggest a subtle physical picture of granular failure, combining liquid-like dependence on deformation rate and solid-like dependence on strain. Our computational methods and results can be used to guide the development of more realistic continuum models, based on observed local relationships betweenaverage variables.

  10. Use of industrial by-products and natural media to adsorb nutrients, metals and organic carbon from drinking water.

    Science.gov (United States)

    Grace, Maebh A; Healy, Mark G; Clifford, Eoghan

    2015-06-15

    Filtration technology is well established in the water sector but is limited by inability to remove targeted contaminants, found in surface and groundwater, which can be damaging to human health. This study optimises the design of filters by examining the efficacy of seven media (fly ash, bottom ash, Bayer residue, granular blast furnace slag (GBS), pyritic fill, granular activated carbon (GAC) and zeolite), to adsorb nitrate, ammonium, total organic carbon (TOC), aluminium, copper (Cu) and phosphorus. Each medium and contaminant was modelled to a Langmuir, Freundlich or Temkin adsorption isotherm, and the impact of pH and temperature (ranging from 10 °C to 29 °C) on their performance was quantified. As retention time within water filters is important in contaminant removal, kinetic studies were carried out to observe the adsorption behaviour over a 24h period. Fly ash and Bayer residue had good TOC, nutrient and Cu adsorption capacity. Granular blast furnace slag and pyritic fill, previously un-investigated in water treatment, showed adsorption potential for all contaminants. In general, pH or temperature adjustment was not necessary to achieve effective adsorption. Kinetic studies showed that at least 60% of adsorption had occurred after 8h for all media. These media show potential for use in a multifunctional water treatment unit for the targeted treatment of specific contaminants. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Nonlocal approach to the analysis of the stress distribution in granular systems. I. Theoretical framework

    Science.gov (United States)

    Kenkre, V. M.; Scott, J. E.; Pease, E. A.; Hurd, A. J.

    1998-05-01

    A theoretical framework for the analysis of the stress distribution in granular materials is presented. It makes use of a transformation of the vertical spatial coordinate into a formal time variable and the subsequent study of a generally non-Markoffian, i.e., memory-possessing (nonlocal) propagation equation. Previous treatments are obtained as particular cases corresponding to, respectively, wavelike and diffusive limits of the general evolution. Calculations are presented for stress propagation in bounded and unbounded media. They can be used to obtain desired features such as a prescribed stress distribution within the compact.

  12. Granular Materials and Risks In ISRU

    Science.gov (United States)

    Behringer, Robert P.; Wilkinson, R. Allen

    2004-01-01

    Working with soil, sand, powders, ores, cement and sintered bricks, excavating, grading construction sites, driving off-road, transporting granules in chutes and pipes, sifting gravel, separating solids from gases, and using hoppers are so routine that it seems straightforward to execute these operations on the Moon and Mars as we do on Earth. We discuss how little these processes are understood and point out the nature of trial-and-error practices that are used in today's massive over-design. Nevertheless, such designs have a high failure rate. Implementation and extensive incremental scaling up of industrial processes are routine because of the inadequate predictive tools for design. We present a number of pragmatic scenarios where granular materials play a role, the risks involved, what some of the basic issues are, and what understanding is needed to greatly reduce the risks. This talk will focus on a particular class of granular flow issues, those that pertain to dense materials, their physics, and the failure problems associated with them. In particular, key issues where basic predictability is lacking include stability of soils for the support of vehicles and facilities, ability to control the flow of dense materials (jamming and flooding/unjamming at the wrong time), the ability to predict stress profiles (hence create reliable designs) for containers such as bunkers or silos. In particular, stress fluctuations, which are not accounted for in standard granular design models, can be very large as granular materials flows, and one result is frequent catastrophic failure of granular devices.

  13. Consideration of reinforcement mechanism in the short fiber mixing granular materials by granular element simulations

    Science.gov (United States)

    Mori, Kentaro; Kaneko, Kenji; Hashizume, Yutaka

    2017-06-01

    The short fiber mixing method is well known as one of the method to improve the strength of gran- ular soils in geotechnical engineering. Mechanical properties of the short fiber mixing granular materials are influenced by many factors, such as the mixture ratio of the short fiber, the material of short fiber, the length, and the orientation. In particular, the mixture ratio of the short fibers is very important in mixture design. In the past study, we understood that the strength is reduced by too much short fiber mixing by a series of tri-axial compression experiments. Namely, there is "optimum mixture ratio" in the short fiber mixing granular soils. In this study, to consider the mechanism of occurrence of the optimum mixture ratio, we carried out the numerical experiments by granular element method. As the results, we can understand that the strength decrease when too much grain-fiber contact points exist, because a friction coefficient is smaller than the grain-grain contact points.

  14. Storage and discharge of a granular fluid

    NARCIS (Netherlands)

    Pacheco-Martinez, Hector; van Gerner, H.J.; Ruiz-Suarez, J.C.

    2008-01-01

    Experiments and computational simulations are carried out to study the behavior of a granular column in a silo whose walls are able to vibrate horizontally. The column is brought to a steady fluidized state and it behaves similar to a hydrostatic system. We study the dynamics of the granular

  15. The role of fluid viscosity in an immersed granular collapse

    Science.gov (United States)

    Yang, Geng Chao; Kwok, Chung Yee; Sobral, Yuri Dumaresq

    2017-06-01

    Instabilities of immersed slopes and cliffs can lead to catastrophic events that involve a sudden release of huge soil mass. The scaled deposit height and runout distance are found to follow simple power laws when a granular column collapses on a horizontal plane. However, if the granular column is submerged in a fluid, the mobility of the granular collapse due to high inertia effects will be reduced by fluid-particle interactions. In this study, the effects of fluid viscosity on granular collapse is investigated qualitatively by adopting a numerical approach based on the coupled lattice Boltzmann method (LBM) and discrete element method (DEM). It is found that the granular collapse can be dramatically slowed down due to the presence of viscous fluids. For the considered granular configuration, when the fluid viscosity increases. the runout distance decreases and the final deposition shows a larger deposit angle.

  16. The role of fluid viscosity in an immersed granular collapse

    Directory of Open Access Journals (Sweden)

    Yang Geng Chao

    2017-01-01

    Full Text Available Instabilities of immersed slopes and cliffs can lead to catastrophic events that involve a sudden release of huge soil mass. The scaled deposit height and runout distance are found to follow simple power laws when a granular column collapses on a horizontal plane. However, if the granular column is submerged in a fluid, the mobility of the granular collapse due to high inertia effects will be reduced by fluid-particle interactions. In this study, the effects of fluid viscosity on granular collapse is investigated qualitatively by adopting a numerical approach based on the coupled lattice Boltzmann method (LBM and discrete element method (DEM. It is found that the granular collapse can be dramatically slowed down due to the presence of viscous fluids. For the considered granular configuration, when the fluid viscosity increases. the runout distance decreases and the final deposition shows a larger deposit angle.

  17. Education and Social Media: Toward a Digital Future. MacArthur Foundation Series on Digital Media and Learning

    Science.gov (United States)

    Greenhow, Christine, Ed.; Sonnevend, Julia, Ed.; Agur, Colin, Ed.

    2016-01-01

    How are widely popular social media such as Facebook, Twitter, and Instagram transforming how teachers teach, how kids learn, and the very foundations of education? What controversies surround the integration of social media in students' lives? The past decade has brought increased access to new media, and with this new opportunities and…

  18. Energy decay in a granular gas collapse

    International Nuclear Information System (INIS)

    Almazán, Lidia; Serero, Dan; Pöschel, Thorsten; Salueña, Clara

    2017-01-01

    An inelastic hard ball bouncing repeatedly off the ground comes to rest in finite time by performing an infinite number of collisions. Similarly, a granular gas under the influence of external gravity, condenses at the bottom of the confinement due to inelastic collisions. By means of hydrodynamical simulations, we find that the condensation process of a granular gas reveals a similar dynamics as the bouncing ball. Our result is in agreement with both experiments and particle simulations, but disagrees with earlier simplified hydrodynamical description. Analyzing the result in detail, we find that the adequate modeling of pressure plays a key role in continuum modeling of granular matter. (paper)

  19. Periurethral granular cell tumor: a case report

    International Nuclear Information System (INIS)

    Kim, Jeong Kon; Choi, Hyo Gyeong; Cho, Kyoung Sik

    1998-01-01

    Granular cell tumors are uncommon soft tissue tumors which arise as solitary or multiple masses. Lesions commonly arise in the head, neck, and chest wall, but can occur in any part of the body. To our knowledge, periurethral granular cell tumor has not been previously reported. We report one such case

  20. Granular motor in the non-Brownian limit

    NARCIS (Netherlands)

    Oyarte Galvez, Loreto Alejandra; van der Meer, Roger M.

    2016-01-01

    In this work we experimentally study a granular rotor which is similar to the famous Smoluchowski–Feynman device and which consists of a rotor with four vanes immersed in a granular gas. Each side of the vanes can be composed of two different materials, creating a rotational asymmetry and turning

  1. Reinventing the Possibilities: Academic Literacy and New Media

    Directory of Open Access Journals (Sweden)

    Ryan 'rylish' Moeller

    2007-01-01

    Full Text Available This webtext demonstrates the possibilities of using new media to teach students critical literacy skills applicable to the 21st century. It is a manifesto for what the authors think writing scholars should be teaching in general-education "writing" classes like first-year composition. In order to answer the question of what we should teach, we have to ask what kinds of academic literacy, if any, we value. The authors argue here that rhetorical theory is a productive way to theorize how meaning is made among new media texts, their designers, and their readers. They use the Ancient Greek concepts of topoi and commonplace to explain how designers and readers enter into a space of negotiated meaning-making when converging upon new media texts. That negotiated space offers a new-media space for learning critical literacies by means other than research papers. As examples, they discuss two student texts and the literacies they demonstrate.

  2. Long runout landslides: a solution from granular mechanics

    Directory of Open Access Journals (Sweden)

    Stanislav eParez

    2015-10-01

    Full Text Available Large landslides exhibit surprisingly long runout distances compared to a rigid body sliding from the same slope, and the mechanism of this phenomena has been studied for decades. This paper shows that the observed long runouts can be explained quite simply via a granular pile flowing downhill, while collapsing and spreading, without the need for frictional weakening that has traditionally been suggested to cause long runouts. Kinematics of the granular flow is divided into center of mass motion and spreading due to flattening of the flowing mass. We solve the center of mass motion analytically based on a frictional law valid for granular flow, and find that center of mass runout is similar to that of a rigid body. Based on the shape of deposits observed in experiments with collapsing granular columns and numerical simulations of landslides, we derive a spreading length Rf~V^1/3. Spreading of a granular pile, leading to a deposit angle much lower than the angle of repose or the dynamic friction angle, is shown to be an important, often dominating, contribution to the total runout distance, accounting for the long runouts observed for natural landslides.

  3. Distrofia corneal granular

    Directory of Open Access Journals (Sweden)

    Alexeide de la C Castillo Pérez

    Full Text Available Las distrofias corneales constituyen un conjunto de enfermedades que presentan, en su mayoría, una baja incidencia y se caracterizan por acúmulo de material hialino o amiloide que disminuyen la transparencia corneal. La distrofia granular es una enfermedad autosómica dominante que presenta opacidades grises en el estroma superficial central de la córnea y se hacen visibles en la primera y segunda décadas de la vida, lo que provoca disminución de la visión más significativa cerca de los 40 años de edad. Presentamos dos casos clínicos de distrofia granular en pacientes hermanos de diferentes sexos, quienes acudieron a la consulta y refirieron visión nublada. El estudio de la historia familiar nos ayuda en el correcto diagnóstico y la biomicroscopia constituye el elemento más importante.

  4. Reactive granular optics for passive tracking of the sun

    Science.gov (United States)

    Frenkel, I.; Niv, A.

    2017-08-01

    The growing need for cost-effective renewable energy sources is hampered by the stagnation in solar cell technology, thus preventing a substantial reduction in the module and energy-production price. Lowering the energy-production cost could be achieved by using modules with efficiency. One of the possible means for increasing the module efficiency is concentrated photovoltaics (CPV). CPV, however, requires complex and accurate active tracking of the sun that reduces much of its cost-effectiveness. Here, we propose a passive tracking scheme based on a reactive optical device. The optical reaction is achieved by a new kind of light activated mechanical force that acts on micron-sized particles. This optical force allows the formation of granular disordered optical media that can be switched from being opaque to become transparent based on the intensity of light it interacts with. Such media gives rise to an efficient passive tracking scheme that when combined with an external optical cavity forms a new solar power conversion approach. Being external to the cell itself, this approach is indifferent to the type of semiconducting material that is used, as well as to other aspects of the cell design. This, in turn, liberates the cell layout from its optical constraints thus paving the way to higher efficiencies at lower module price.

  5. Small-signal analysis of granular semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Varpula, Aapo; Sinkkonen, Juha; Novikov, Sergey, E-mail: aapo.varpula@tkk.f [Department of Micro and Nanosciences, Aalto University, PO Box 13500, FI-00076 Aalto, Espoo (Finland)

    2010-11-01

    The small-signal ac response of granular n-type semiconductors is calculated analytically using the drift-diffusion theory when electronic trapping at grain boundaries is present. An electrical equivalent circuit (EEC) model of a granular n-type semiconductor is presented. The analytical model is verified with numerical simulation performed by SILVACO ATLAS. The agreement between the analytical and numerical results is very good in a broad frequency range at low dc bias voltages.

  6. Small-signal analysis of granular semiconductors

    International Nuclear Information System (INIS)

    Varpula, Aapo; Sinkkonen, Juha; Novikov, Sergey

    2010-01-01

    The small-signal ac response of granular n-type semiconductors is calculated analytically using the drift-diffusion theory when electronic trapping at grain boundaries is present. An electrical equivalent circuit (EEC) model of a granular n-type semiconductor is presented. The analytical model is verified with numerical simulation performed by SILVACO ATLAS. The agreement between the analytical and numerical results is very good in a broad frequency range at low dc bias voltages.

  7. Applicability and trends of anaerobic granular sludge treatment processes

    International Nuclear Information System (INIS)

    Lim, Seung Joo; Kim, Tak-Hyun

    2014-01-01

    Anaerobic granular sludge treatment processes have been continuously developed, although the anaerobic sludge granulation process was not clearly understood. In this review, an upflow anaerobic sludge blanket (UASB), an expanded granule sludge blanket (EGSB), and a static granular bed reactor (SGBR) were introduced as components of a representative anaerobic granular sludge treatment processes. The characteristics and application trends of each reactor were presented. The UASB reactor was developed in the late 1970s and its use has been rapidly widespread due to the excellent performance. With the active granules, this reactor is able to treat various high-strength wastewaters as well as municipal wastewater. Most soluble industrial wastewaters can be efficiently applied using a UASB. The EGSB reactor was developed owing to give more chance to contact between wastewater and the granules. Dispersed sludge is separated from mature granules using the rapid upward velocity in this reactor. The EGSB reactor shows the excellent performance in treating low-strength and/or high-strength wastewater, especially under low temperatures. The SGBR, developed at Iowa State University, is one of anaerobic granular sludge treatment processes. Although the configuration of the SGBR is very simple, the performance of this system is similar to that of the UASB or EGSB reactor. The anaerobic sludge granulation processes showed excellent performance for various wastewaters at a broad range of organic loading rate in lab-, pilot-scale tests. This leads to erect thousands of full-scale granular processes, which has been widely operated around the world. -- Highlights: • Anaerobic sludge granulation is a key parameter for maintaining granular processes. • Anaerobic granular digestion processes are applicable for various wastewaters. • The UASB is an economic high-rate anaerobic granular process. • The EGSB can treat high-strength wastewater using expanding granules. • The SGBR is

  8. Oblique shock waves in granular flows over bluff bodies

    Directory of Open Access Journals (Sweden)

    Gopan Nandu

    2017-01-01

    Full Text Available Granular flows around an object have been the focus of numerous analytical, experimental and simulation studies. The structure and nature of the oblique shock wave developed when a quasi-two dimensional flow of spherical granular particles streams past an immersed, fixed cylindrical obstacle forms the focus of this study. The binary granular mixture, consisting of particles of the same diameter but different material properties, is investigated by using a modified LIGGGHTS package as the simulation engine. Variations in the solid fraction and granular temperature within the resulting flow are studied. The Mach number is calculated and is used to distinguish between the subsonic and the supersonic regions of the bow shock.

  9. 76 FR 8774 - Granular Polytetrafluoroethylene Resin From Japan

    Science.gov (United States)

    2011-02-15

    ... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-386 (Third Review)] Granular Polytetrafluoroethylene Resin From Japan AGENCY: United States International Trade Commission. ACTION: Termination of five... revocation of the antidumping duty order on granular polytetrafluoroethylene resin from Japan would be likely...

  10. Students' Perspectives of the Impact of Online Streaming Media on Teaching and Learning at the College of Education at Kuwait University

    Science.gov (United States)

    Safar, Ammar; Alkhezzi, Fahad

    2016-01-01

    The objective of this study was to investigate the perspectives of pre-service and in-service teachers in the College of Education (COE) at Kuwait University (KU) on the use of online streaming media services as a facilitative and innovative tool for teaching, learning, professional development, and teacher preparation. Five research questions…

  11. Penggunaan Internet sebagai Media Baru dalam Pembelajaran

    OpenAIRE

    Gafar, Abdoel

    2008-01-01

    The developement of information and communication technology ( ICT) has changed our way of looking at things including teaching media. This article discusses the advantages and disadvantages of using internet in teaching and learning process.

  12. Child health in the information age: media education of pediatricians.

    Science.gov (United States)

    Rich, M; Bar-On, M

    2001-01-01

    Substantial research has associated exposure to entertainment media with increased levels of interpersonal violence, risky sexual behavior, body image distortion, substance abuse, and obesity. The objective of this study was to determine what pediatric residency programs are teaching trainees about media and the influence of media on the physical and mental health of children and adolescents. Survey of residency curricula, consisting of 17 items about children's exposure to media, including television, movies, popular music, computer/video games and the Internet, the effects of this exposure on specific health risks, and associations between program characteristics and media education in the residency curriculum. Participants. Directors of the 209 accredited pediatric residency programs in the United States. Two hundred four programs (97.6%) responded. Fifty-eight programs (28.4%) offered formal education on 1 or more types of media; 60 programs (29.4%) discussed the influences of media when teaching about specific health conditions. Residents in 96 programs (47.1%) were encouraged to discuss media use with patients and parents; 13 programs (6.4%) taught media literacy as an intervention. Among program characteristics, only media training received by program directors was significantly associated with inclusion of media in residency curricula. Despite increasing awareness of media influence on child health, less than one-third of US pediatric residency programs teach about media exposure. Developing a pediatric media curriculum and training pediatric residency directors or designated faculty may be a resource-effective means of improving health for children growing up in a media-saturated environment.

  13. The Use of Social Media in Teaching Race

    Science.gov (United States)

    Nakagawa, Kathy; Arzubiaga, Angela E.

    2014-01-01

    This article explores ways in which race pedagogy interrogates social media as a significant influence on racism and source for race understandings. Social media serves as a context in which to learn about, challenge, and address issues of race. We discuss how social media may be used to promote racial literacy and question and resist racism,…

  14. Collapse of tall granular columns in fluid

    Science.gov (United States)

    Kumar, Krishna; Soga, Kenichi; Delenne, Jean-Yves

    2017-06-01

    Avalanches, landslides, and debris flows are geophysical hazards, which involve rapid mass movement of granular solids, water, and air as a multi-phase system. In order to describe the mechanism of immersed granular flows, it is important to consider both the dynamics of the solid phase and the role of the ambient fluid. In the present study, the collapse of a granular column in fluid is studied using 2D LBM - DEM. The flow kinematics are compared with the dry and buoyant granular collapse to understand the influence of hydrodynamic forces and lubrication on the run-out. In the case of tall columns, the amount of material destabilised above the failure plane is larger than that of short columns. Therefore, the surface area of the mobilised mass that interacts with the surrounding fluid in tall columns is significantly higher than the short columns. This increase in the area of soil - fluid interaction results in an increase in the formation of turbulent vortices thereby altering the deposit morphology. It is observed that the vortices result in the formation of heaps that significantly affects the distribution of mass in the flow. In order to understand the behaviour of tall columns, the run-out behaviour of a dense granular column with an initial aspect ratio of 6 is studied. The collapse behaviour is analysed for different slope angles: 0°, 2.5°, 5° and 7.5°.

  15. Traffic and Granular Flow '11

    CERN Document Server

    Buslaev, Alexander; Bugaev, Alexander; Yashina, Marina; Schadschneider, Andreas; Schreckenberg, Michael; TGF11

    2013-01-01

    This book continues the biannual series of conference proceedings, which has become a classical reference resource in traffic and granular research alike. It addresses new developments at the interface between physics, engineering and computational science. Complex systems, where many simple agents, be they vehicles or particles, give rise to surprising and fascinating phenomena.   The contributions collected in these proceedings cover several research fields, all of which deal with transport. Topics include highway, pedestrian and internet traffic, granular matter, biological transport, transport networks, data acquisition, data analysis and technological applications. Different perspectives, i.e. modeling, simulations, experiments and phenomenological observations, are considered.

  16. Incorporating active-learning techniques into the photonics-related teaching in the Erasmus Mundus Master in "Color in Informatics and Media Technology"

    Science.gov (United States)

    Pozo, Antonio M.; Rubiño, Manuel; Hernández-Andrés, Javier; Nieves, Juan L.

    2014-07-01

    In this work, we present a teaching methodology using active-learning techniques in the course "Devices and Instrumentation" of the Erasmus Mundus Master's Degree in "Color in Informatics and Media Technology" (CIMET). A part of the course "Devices and Instrumentation" of this Master's is dedicated to the study of image sensors and methods to evaluate their image quality. The teaching methodology that we present consists of incorporating practical activities during the traditional lectures. One of the innovative aspects of this teaching methodology is that students apply the concepts and methods studied in class to real devices. For this, students use their own digital cameras, webcams, or cellphone cameras in class. These activities provide students a better understanding of the theoretical subject given in class and encourage the active participation of students.

  17. A particle-based method for granular flow simulation

    KAUST Repository

    Chang, Yuanzhang; Bao, Kai; Zhu, Jian; Wu, Enhua

    2012-01-01

    We present a new particle-based method for granular flow simulation. In the method, a new elastic stress term, which is derived from a modified form of the Hooke's law, is included in the momentum governing equation to handle the friction of granular materials. Viscosity force is also added to simulate the dynamic friction for the purpose of smoothing the velocity field and further maintaining the simulation stability. Benefiting from the Lagrangian nature of the SPH method, large flow deformation can be well handled easily and naturally. In addition, a signed distance field is also employed to enforce the solid boundary condition. The experimental results show that the proposed method is effective and efficient for handling the flow of granular materials, and different kinds of granular behaviors can be well simulated by adjusting just one parameter. © 2012 Science China Press and Springer-Verlag Berlin Heidelberg.

  18. A particle-based method for granular flow simulation

    KAUST Repository

    Chang, Yuanzhang

    2012-03-16

    We present a new particle-based method for granular flow simulation. In the method, a new elastic stress term, which is derived from a modified form of the Hooke\\'s law, is included in the momentum governing equation to handle the friction of granular materials. Viscosity force is also added to simulate the dynamic friction for the purpose of smoothing the velocity field and further maintaining the simulation stability. Benefiting from the Lagrangian nature of the SPH method, large flow deformation can be well handled easily and naturally. In addition, a signed distance field is also employed to enforce the solid boundary condition. The experimental results show that the proposed method is effective and efficient for handling the flow of granular materials, and different kinds of granular behaviors can be well simulated by adjusting just one parameter. © 2012 Science China Press and Springer-Verlag Berlin Heidelberg.

  19. The Scope of Digital Image Media in Art Education

    Science.gov (United States)

    Ortegren, Hans

    2012-01-01

    In this case study of forms 7-9 in a Swedish school, the subject conceptions of and teaching practices in art subjects of schoolteachers and pupils are studied, in particular with regard to digital media. How the core content of a subject is conceived is compared to the importance of digital media in the teaching practice. For three years a class…

  20. Neurohypophysis granular cell tumours. Upon neurohypophysis rare tumours

    International Nuclear Information System (INIS)

    Barrande, G.; Kujas, M.; Gancel, A.; Turpin, G.; Bruckert, E.; Kuhn, J.M.; Luton, J.P.

    1995-01-01

    Granular cell tumours of neurohypophysis are rare. These tumours are more often encountered as incidental autopsy findings seen in up to 17 % of unselected adult autopsy cases. There are few reports of para-sellar granular cell tumours large enough to cause symptoms. We present three cases of neurohypophysis granular cell tumour and a review of the literature. In one patient, the asymptomatic granular cell tumour was incidentally discovered at surgical removal of a corticotrophic micro-adenoma. The remaining 2 patients had a symptomatic tumour which caused neurological symptoms such as visual disturbance and headaches and endocrine disorders such as hypopituitarism or hyper-prolactinaemia. In these 2 cases, computerized tomography showed a well-circumscribed, contrast-enhanced, intra-sellar and supra-sellar mass. Magnetic resonance imaging demonstrated an isointense gadolinium-enhanced mass in T1-weighted-images. Trans-sphenoidal partial resection was performed and histology was interpreted as a granular cell tumour. The immunohistochemical study was positive for glial fibrillary acidic protein (GEAP) and neuron specific enolase (NSE) in 1 of the 2 tumours and positive for S100 protein and vimentin in both tumours but negative for CD68. The histogenesis of neurohypophysis granular cell tumours is still controversial but ultrastructural and immunohistochemical studies support the theory that may arise from pituicytes, the glial cells of neurohypophysis. Management of these benign, slow growing, tumours is based mainly on neurosurgical resection. Data from the literature do not support a beneficial effect of post operative radiation therapy on postoperative recurrences. (authors). 23 refs., 4 figs., 1 tab

  1. Granular Cell Tumor

    African Journals Online (AJOL)

    1). Her packed cell volume was 40%, she was system, gastro-intestinal tract, brain, heart, and negative to human immunodeficiency virus. 2 female reproductive . ... histocytes and neurons at various times. They granules. The granules are probably of lysosmal were consequently termed granular cell origin and contain ...

  2. Development of granular powder manufacturing technology by spray pyrolysis

    International Nuclear Information System (INIS)

    Katoh, Yoshiyuki; Kawase, Keiichi; Takahashi, Yoshiharu; Todokoro, Akio

    1996-01-01

    For shortening of mixed-oxide (MOX) fuel manufacturing process and improvement in treatment of MOX-powder, we have been developing the granular powder production technology. Since the granular powders have excellent fluidity owing to the spherical shape, there is the possibility of modifying scattering and adcering of the powder in the process equipment. In this paper, spray pyrolysis process in adopted as the process of manufacturing the granular powders and the basic feasibility study has been carried out. The experimental results show that the manufactured granular powders have excellent fluidity and the diameter of the powders is controllable. Furthermore, high density pellets are formed by sintering the powders. Thus, it is clarified that this process is promising for the actual MOX fuel fabrication. (author)

  3. Enhanced selection of micro-aerobic pentachlorophenol degrading granular sludge

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Yuancai, E-mail: donkey1204@hotmail.com [State Key Laboratory of Pulp and Paper Engineering, College of Light Industry and Food Science, South China University of Technology, Guangzhou 510640 (China); Chen, Yuancai, E-mail: chenyc@scut.edu.cn [State Key Laboratory of Pulp and Paper Engineering, College of Light Industry and Food Science, South China University of Technology, Guangzhou 510640 (China); Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, College of Environment and Energy, South China University of Technology, Guangzhou 510006 (China); Song, Wenzhe, E-mail: songwenzhe007@126.com [Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, College of Environment and Energy, South China University of Technology, Guangzhou 510006 (China); Hu, Yongyou, E-mail: ppyyhu@scut.edu.cn [State Key Laboratory of Pulp and Paper Engineering, College of Light Industry and Food Science, South China University of Technology, Guangzhou 510640 (China); Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, College of Environment and Energy, South China University of Technology, Guangzhou 510006 (China)

    2014-09-15

    Graphical abstract: In this work, an aerobic column reactor was placed before the USB to maintain micro-oxygen condition in the reactor and the micro-aerobic pentachlorophenol (PCP) degrading granular sludge under oxygen-limited conditions (0.1–0.2 mg L{sup −1}) was successfully obtained. PCP degradation by the micro-aerobic system was studied and the variance of microbial community was also discussed by using PCR-DGGE analysis. - Highlights: • Micro-aerobic granular sludge was cultivated in column-type combined reactors. • PCP biodegradation, VFA accumulation and biogas production were studied. • The function of Methanogenic archaeon in the system was investigated. • Fluctuation and diversity of microbial community were discussed by DGGE analysis. • The dominated microorganisms were identified by 16S rDNA sequences. - Abstract: Column-type combined reactors were designed to cultivate micro-aerobic pentachlorophenol (PCP) degrading granular sludge under oxygen-limited conditions (0.1–0.2 mg L{sup −1}) over 39-day experimental period. Micro-aerobic granular had both anaerobic activity (SMA: 2.34 mMCH{sub 4}/h g VSS) and aerobic activity (SOUR: 2.21 mMO{sub 2}/h g VSS). Metabolite analysis results revealed that PCP was sequentially dechlorinated to TCP, DCP, and eventually to MCP. Methanogens were not directly involved in the dechlorination of PCP, but might played a vital role in stabilizing the overall structure of the granule sludge. For Eubacteria, the Shannon Index (2.09 in inoculated granular sludge) increased both in micro-aerobic granular sludge (2.61) and PCP-degradation granular sludge (2.55). However, for Archaea, it decreased from 2.53 to 1.85 and 1.84, respectively. Although the Shannon Index demonstrated slight difference between micro-aerobic granular sludge and PCP-degradation granular sludge, the Principal Component Analysis (PCA) indicated obvious variance of the microbial composition, revealing significant effect of micro

  4. Enhanced selection of micro-aerobic pentachlorophenol degrading granular sludge

    International Nuclear Information System (INIS)

    Lv, Yuancai; Chen, Yuancai; Song, Wenzhe; Hu, Yongyou

    2014-01-01

    Graphical abstract: In this work, an aerobic column reactor was placed before the USB to maintain micro-oxygen condition in the reactor and the micro-aerobic pentachlorophenol (PCP) degrading granular sludge under oxygen-limited conditions (0.1–0.2 mg L −1 ) was successfully obtained. PCP degradation by the micro-aerobic system was studied and the variance of microbial community was also discussed by using PCR-DGGE analysis. - Highlights: • Micro-aerobic granular sludge was cultivated in column-type combined reactors. • PCP biodegradation, VFA accumulation and biogas production were studied. • The function of Methanogenic archaeon in the system was investigated. • Fluctuation and diversity of microbial community were discussed by DGGE analysis. • The dominated microorganisms were identified by 16S rDNA sequences. - Abstract: Column-type combined reactors were designed to cultivate micro-aerobic pentachlorophenol (PCP) degrading granular sludge under oxygen-limited conditions (0.1–0.2 mg L −1 ) over 39-day experimental period. Micro-aerobic granular had both anaerobic activity (SMA: 2.34 mMCH 4 /h g VSS) and aerobic activity (SOUR: 2.21 mMO 2 /h g VSS). Metabolite analysis results revealed that PCP was sequentially dechlorinated to TCP, DCP, and eventually to MCP. Methanogens were not directly involved in the dechlorination of PCP, but might played a vital role in stabilizing the overall structure of the granule sludge. For Eubacteria, the Shannon Index (2.09 in inoculated granular sludge) increased both in micro-aerobic granular sludge (2.61) and PCP-degradation granular sludge (2.55). However, for Archaea, it decreased from 2.53 to 1.85 and 1.84, respectively. Although the Shannon Index demonstrated slight difference between micro-aerobic granular sludge and PCP-degradation granular sludge, the Principal Component Analysis (PCA) indicated obvious variance of the microbial composition, revealing significant effect of micro-aerobic condition and

  5. Thermal effects and in-plane magnetic anisotropy in thin-film recording media

    International Nuclear Information System (INIS)

    Ajan, Antony; Abarra, E.N.; Acharya, B.R.; Inomata, A.; Okamoto, I.; Shinohara, M.

    2003-01-01

    The effect of thermal activation on the in-plane magnetic anisotropy [measured as orientation ratio (OR)] of granular longitudinal magnetic recording media is investigated. Temperature and time dependent studies were made on media with different magnetic layer thicknesses. We find that OR is independent of temperature for a stable medium but shows a large increase with temperature for thermally unstable media. At low temperatures and high field sweep rates, the OR values are found to be the same, independent of the magnetic layer thickness. The unique value when thermal activation is reduced is consistent with the high population of the cobalt c axes along the texturing direction as the origin of anisotropy

  6. Engaging Students with Social Media

    Science.gov (United States)

    Bal, Anjali S.; Grewal, Dhruv; Mills, Adam; Ottley, Gary

    2015-01-01

    The importance of social media for marketing professionals has grown immensely as consumers turn to it to connect with products, brands, and brand communities. Yet limited research investigates the uses of social media to teach core marketing concepts. This article analyzes coursework in foundational marketing classes, with a specific focus on the…

  7. Pemanfaatan Media Dalam Pembelajaran Biologi Di Sekolah

    OpenAIRE

    Emda, Amna

    2011-01-01

    In teaching learning process, teachers have to use some media of instruction. They have to be able to select appropriate media with the concept that they want to teach. In biology, especially the concept of biodiversity, the teacher should explain and introduce the students to various plants available around them including herb plants. It will be one of solution for a teacher to achieve an optimum goal if they can use the diverse plant around them. The successful of learning especially in the...

  8. Media Literacy Art Education: Logos, Culture Jamming, and Activism

    Science.gov (United States)

    Chung, Sheng Kuan; Kirby, Michael S.

    2009-01-01

    Critical media literacy art education teaches students to: (1) appreciate the aesthetic qualities of media; (2) critically negotiate meanings and analyze media culture as products of social struggle; and (3) use media technologies as instruments of creative expression and social activism. In concert with art education practices oriented toward…

  9. Jamming by compressing a system of granular crosses

    Science.gov (United States)

    Zheng, Hu; Wang, Dong; Barés, Jonathan; Behringer, Robert

    2017-06-01

    A disordered stress-free granular packing can be jammed, transformed into a mechanically rigid structure, by increasing the density of particles or by applying shear deformation. The jamming behavior of systems made of 2D circular discs has been investigated in detail, but very little is known about jamming for non-spherical particles, and particularly, non-convex particles. Here, we perform an experimental study on jamming by compression of a system of quasi-2D granular crosses made of photo-elastic crosses. We measure the pressure evolution during cyclic compression and decompression. The Jamming packing fraction of these quasi-2D granular crosses is ϕJ ≃ 0.475, which is much smaller than the value ϕJ ≃ 0.84 for-2D granular disks. The packing fraction shifts systematically to higher values under compressive cycling, corresponding to systematic shifts in the stress-strain response curves. Associated with these shifts are rotations of the crosses, with minimal changes in their centers of mass.

  10. Media Culture 2020: Collaborative Teaching and Blended Learning Using Social Media and Cloud-Based Technologies

    Science.gov (United States)

    Vickers, Richard; Field, James; Melakoski, Cai

    2015-01-01

    In 2013 five universities from across Europe undertook an innovative project "Media Culture 2020", combining skills and forces to develop new practices that would face the challenge of the convergence of digital media, taking full advantage of social media and cloud-based technologies. The aim of the Media Culture 2020 project was to…

  11. Vortex jamming in superconductors and granular rheology

    International Nuclear Information System (INIS)

    Yoshino, Hajime; Nogawa, Tomoaki; Kim, Bongsoo

    2009-01-01

    We demonstrate that a highly frustrated anisotropic Josephson junction array (JJA) on a square lattice exhibits a zero-temperature jamming transition, which shares much in common with those in granular systems. Anisotropy of the Josephson couplings along the horizontal and vertical directions plays roles similar to normal load or density in granular systems. We studied numerically static and dynamic response of the system against shear, i.e. injection of external electric current at zero temperature. Current-voltage curves at various strength of the anisotropy exhibit universal scaling features around the jamming point much as do the flow curves in granular rheology, shear-stress versus shear-rate. It turns out that at zero temperature the jamming transition occurs right at the isotropic coupling and anisotropic JJA behaves as exotic fragile vortex matter: it behaves as a superconductor (vortex glass) in one direction, whereas it is a normal conductor (vortex liquid) in the other direction even at zero temperature. Furthermore, we find a variant of the theoretical model for the anisotropic JJA quantitatively reproduces universal master flow-curves of the granular systems. Our results suggest an unexpected common paradigm stretching over seemingly unrelated fields-the rheology of soft materials and superconductivity.

  12. Teaching Social Media in Business

    Science.gov (United States)

    McHaney, Roger; Warkentin, Merrill; Sachs, David; Pope, Michael Brian; Ormond, Dustin

    2015-01-01

    The ways people connect, interact, share, and communicate have changed due to recent developments in information technology. These developments, categorized as social media, have captured the attention of business executives, technologists, and education professionals alike, and have altered many business models. Additionally, the concept of…

  13. A case study: the effectiveness of social media and online resources in the teaching of junior science

    OpenAIRE

    Doherty, Michael

    2013-01-01

    non-peer-reviewed The purpose of this research, in the form of a case study, is to attempt to utilize both social media and online materials in order to motivate student learning and reduce dependency on the teacher-led model of teaching and learning which is still prevalent in schools. The setting will be that of a second level rural school in North West Ireland and the context will be that of a junior cycle student cohort being taught sections of the current junior certificate science...

  14. Investigation of granular impact using positron emission particle tracking

    KAUST Repository

    Marston, Jeremy O.

    2015-04-01

    We present results from an experimental study of granular impact using a combination of high-speed video and positron emission particle tracking (PEPT). The PEPT technique exploits the annihilation of photons from positron decay to determine the position of tracer particles either inside a small granular bed or attached to the object which impacts the bed. We use dense spheres as impactors and the granular beds are comprised of glass beads which are fluidised to achieve a range of different initial packing states. For the first time, we have simultaneously investigated both the trajectory of the sphere, the motion of particles in a 3-D granular bed and particles which jump into the resultant jet, which arises from the collapse of the cavity formed by the impacting sphere.

  15. Auto Workshop Teaches Media Skills

    Science.gov (United States)

    Harris, Richard; Brejcha, Mathias F.

    1976-01-01

    To meet the need for technical updating and media development for automotive teachers, a short course was offered on the campus of Ferris State College in the summer of 1975. The innovative program proved highly practical in implementation and was favorably evaluated by the participants. (Author/BP)

  16. Paraqueratose granular: relato de seis casos em crianças Granular parakeratosis: a report of six cases in children

    Directory of Open Access Journals (Sweden)

    Susana Giraldi

    2006-02-01

    Full Text Available A paraqueratose granular é alteração da queratinização, primeiramente descrita em adultos, caracterizada por pápulas e placas hiperqueratósicas nas áreas intertriginosas. Os autores descrevem seis casos de paraqueratose granular em crianças. Um paciente apresentava lesões nas regiões glúteas, dois em ambas as axilas e região cervical (apresentações inéditas na literatura. Três pacientes apresentavam lesões em pregas inguinais. Realizam também revisão da literatura e discutem a possível etiologia dessa rara dermatose.Granular parakeratosis is an alteration of keratinization that was first described in adults. It is characterized by hiperkeratotic plaques and papules in intertriginous areas. The authors describe six cases of granular parakeratosis in children. One patient had lesions on the buttocks; two children presented papules in both axillae and cervical region (presentations never described before in the literature. The remaining three patients presented with lesions in the inguinal folds. Review of the literature and discussion on the pathogenesis of this rare dermatosis are presented.

  17. Intermediality: Bridge to Critical Media Literacy.

    Science.gov (United States)

    Pailliotet, Ann Watts; Semali, Ladislaus; Rodenberg, Rita K.; Giles, Jackie K.; Macaul, Sherry L.

    2000-01-01

    Defines "intermediality" as the ability to critically read and write with and across varied symbol systems. Relates it to critical media literacy. Offers rationales for teaching critical media literacy in general, and intermedial instruction in particular. Identifies seven guiding intermedial elements: theory, texts, processes, contexts,…

  18. Media use, face-to-face communication, media multitasking, and social well-being among 8- to 12-year-old girls.

    Science.gov (United States)

    Pea, Roy; Nass, Clifford; Meheula, Lyn; Rance, Marcus; Kumar, Aman; Bamford, Holden; Nass, Matthew; Simha, Aneesh; Stillerman, Benjamin; Yang, Steven; Zhou, Michael

    2012-03-01

    An online survey of 3,461 North American girls ages 8-12 conducted in the summer of 2010 through Discovery Girls magazine examined the relationships between social well-being and young girls' media use--including video, video games, music listening, reading/homework, e-mailing/posting on social media sites, texting/instant messaging, and talking on phones/video chatting--and face-to-face communication. This study introduced both a more granular measure of media multitasking and a new comparative measure of media use versus time spent in face-to-face communication. Regression analyses indicated that negative social well-being was positively associated with levels of uses of media that are centrally about interpersonal interaction (e.g., phone, online communication) as well as uses of media that are not (e.g., video, music, and reading). Video use was particularly strongly associated with negative social well-being indicators. Media multitasking was also associated with negative social indicators. Conversely, face-to-face communication was strongly associated with positive social well-being. Cell phone ownership and having a television or computer in one's room had little direct association with children's socioemotional well-being. We hypothesize possible causes for these relationships, call for research designs to address causality, and outline possible implications of such findings for the social well-being of younger adolescents. PsycINFO Database Record (c) 2012 APA, all rights reserved.

  19. Teacher training: the use of media content and technology in the process of teaching and learning in higher education - doi: 10.4025/actascieduc.v33i1.11307

    Directory of Open Access Journals (Sweden)

    Cláudia Cristina Batistela Francisco

    2011-07-01

    Full Text Available This article aims to discuss and analyze media content and use of Information and Communication Technology - ICT in teaching and learning in higher education institutions, reflecting on issues of teacher education. For that, we held a discussion in the literature that presents the difficulties faced by teachers in this new educational reality, raising questions about their training, and how they should act in a way that learning is carried with media students, with support of technologies and media

  20. A Fractal Study on the Effective Thermal Conductivity of Porous Media

    Science.gov (United States)

    Qin, X.; Cai, J.; Wei, W.

    2017-12-01

    Thermal conduction in porous media has steadily received attention in science and engineering, for instance, exploiting and utilizing the geothermal energy, developing the oil-gas resource, ground water flow in hydrothermal systems and investigating the potential host nuclear wastes, etc. The thermal conductivity is strongly influenced by the microstructure features of porous media. In this work, based on the fractal characteristics of the grains, a theoretical model of effective thermal conductivity is proposed for saturated and unsaturated porous media. It is found that the proposed effective thermal conductivity solution is a function of geometrical parameters of porous media, such as the porosity, fractal dimension of granular matrix and the thermal conductivity of the grains and pore fluid. The model predictions are compared with existing experimental data and the results show that they are in good agreement with existing experimental data. The proposed model may provide a better understanding of the physical mechanisms of thermal transfer in porous media than conventional models.

  1. Anaerobic granular sludge and biofilm reactors

    DEFF Research Database (Denmark)

    Skiadas, Ioannis V.; Gavala, Hariklia N.; Schmidt, Jens Ejbye

    2003-01-01

    by the immobilization of the biomass, which forms static biofilms, particle-supported biofilms, or granules depending on the reactor's operational conditions. The advantages of the high-rate anaerobic digestion over the conventional aerobic wastewater treatment methods has created a clear trend for the change......-rate anaerobic treatment systems based on anaerobic granular sludge and biofilm are described in this chapter. Emphasis is given to a) the Up-flow Anaerobic Sludge Blanket (UASB) systems, b) the main characteristics of the anaerobic granular sludge, and c) the factors that control the granulation process...

  2. USE OF GRANULAR GRAPHITE FOR ELECTROLYTIC DECHLORINATION OF TRICHLOROETHYLENE

    Science.gov (United States)

    Granular graphite is a potential electrode material for the electrochemical remediation of refractory chlorinated organic compounds such as trichloroethylene (TCE). However, the use of granular graphite can complicate the experimental results. On one hand, up to 99% of TCE was re...

  3. 11th Traffic and Granular Flow Conference

    CERN Document Server

    Daamen, Winnie

    2016-01-01

    The Conference on Traffic and Granular Flow brings together international researchers from different fields ranging from physics to computer science and engineering to discuss the latest developments in traffic-related systems. Originally conceived to facilitate new ideas by considering the similarities of traffic and granular flow, TGF'15, organised by Delft University of Technology, now covers a broad range of topics related to driven particle and transport systems. Besides the classical topics of granular flow and highway traffic, its scope includes data transport (Internet traffic), pedestrian and evacuation dynamics, intercellular transport, swarm behaviour and the collective dynamics of other biological systems. Recent advances in modelling, computer simulation and phenomenology are presented, and prospects for applications, for example to traffic control, are discussed. The conference explores the interrelations between the above-mentioned fields and offers the opportunity to stimulate interdisciplinar...

  4. The Granular Blasius Problem: High inertial number granular flows

    Science.gov (United States)

    Tsang, Jonathan; Dalziel, Stuart; Vriend, Nathalie

    2017-11-01

    The classical Blasius problem considers the formation of a boundary layer through the change at x = 0 from a free-slip to a no-slip boundary beneath an otherwise steady uniform flow. Discrete particle model (DPM) simulations of granular gravity currents show that a similar phenomenon exists for a steady flow over a uniformly sloped surface that is smooth upstream (allowing slip) but rough downstream (imposing a no-slip condition). The boundary layer is a region of high shear rate and therefore high inertial number I; its dynamics are governed by the asymptotic behaviour of the granular rheology as I -> ∞ . The μ(I) rheology asserts that dμ / dI = O(1 /I2) as I -> ∞ , but current experimental evidence is insufficient to confirm this. We show that `generalised μ(I) rheologies', with different behaviours as I -> ∞ , all permit the formation of a boundary layer. We give approximate solutions for the velocity profile under each rheology. The change in boundary condition considered here mimics more complex topography in which shear stress increases in the streamwise direction (e.g. a curved slope). Such a system would be of interest in avalanche modelling. EPSRC studentship (Tsang) and Royal Society Dorothy Hodgkin Fellowship (Vriend).

  5. Social Media Tips to Enhance Medical Education.

    Science.gov (United States)

    Shah, Vikas; Kotsenas, Amy L

    2017-06-01

    In this article, we describe how social media can supplement traditional education, articulate the advantages and disadvantages of various social media platforms for both teachers and learners, discuss best practices to maintain confidentiality of protected health information, and provide tips for implementing social media-based teaching into the training curriculum. Copyright © 2017 The Association of University Radiologists. All rights reserved.

  6. Granular cell tumor: An uncommon benign neoplasm

    Directory of Open Access Journals (Sweden)

    Tirthankar Gayen

    2015-01-01

    Full Text Available Granular cell tumor is a distinctly rare neoplasm of neural sheath origin. It mainly presents as a solitary asymptomatic swelling in the oral cavity, skin, and rarely internal organs in the middle age. Histopathology is characteristic, showing polyhedral cells containing numerous fine eosinophilic granules with indistinct cell margins. We present a case of granular cell tumor on the back of a 48-year-old woman which was painful, mimicking an adnexal tumor.

  7. Dynamics of crater formations in immersed granular materials

    Science.gov (United States)

    Varas, G.; Vidal, V.; Géminard, J.

    2009-12-01

    Craters are part of the widespread phenomena observed in nature. Among the main applications to natural phenomena, aside from meteorite impact craters, are the formation and growth of volcanic edifices, by successive ejecta emplacement and/or erosion. The time evolution and dynamics play a crucial role here, as the competition between volcanic-jet mass-flux (degassing and ejecta) and crater-size evolution may control directly the eruptive regime. Crater morphology in dry granular material has been extensively studied, both experimentally and theoretically. Most of these studies investigate the final, steady crater shape resulting from the collision of solid bodies with the material surface and scaling laws are derived. In immersed granular material, craters generated by an underwater vortex ring, or underwater impact craters generated by landslide, have been reported. In a previous experimental study, Gostiaux et al. [Gran. Matt., 2002] have investigated the dynamics of air flowing through an immersed granular layer. They reported that, depending on the flow rate, the system exhibits two qualitatively different regimes: At small flow rate, the bubbling regime during which bubbles escape the granular layer independently one from another; At large flow rate, the open-channel regime which corresponds to the formation of a channel crossing the whole thickness of the granular bed through which air escapes almost continuously. At intermediate flow rate, a spontaneous alternation between these two regimes is observed. Here, we report the dynamics of crater formations at the free surface of an immersed granular bed, locally crossed by an ascending gas flow. We reproduce the experimental conditions of Gostiaux et al. (2002) in two dimensions: In a vertical Hele-Shaw cell, the crater consists of two sand piles which develop around the location of the gas emission. We observe that the typical size of the crater increases logarithmically with time, independently of the gas

  8. Modeling of light dynamic cone penetration test - Panda 3 ® in granular material by using 3D Discrete element method

    Science.gov (United States)

    Tran, Quoc Anh; Chevalier, Bastien; Benz, Miguel; Breul, Pierre; Gourvès, Roland

    2017-06-01

    The recent technological developments made on the light dynamic penetration test Panda 3 ® provide a dynamic load-penetration curve σp - sp for each impact. This curve is influenced by the mechanical and physical properties of the investigated granular media. In order to analyze and exploit the load-penetration curve, a numerical model of penetration test using 3D Discrete Element Method is proposed for reproducing tests in dynamic conditions in granular media. All parameters of impact used in this model have at first been calibrated by respecting mechanical and geometrical properties of the hammer and the rod. There is a good agreement between experimental results and the ones obtained from simulations in 2D or 3D. After creating a sample, we will simulate the Panda 3 ®. It is possible to measure directly the dynamic load-penetration curve occurring at the tip for each impact. Using the force and acceleration measured in the top part of the rod, it is possible to separate the incident and reflected waves and then calculate the tip's load-penetration curve. The load-penetration curve obtained is qualitatively similar with that obtained by experimental tests. In addition, the frequency analysis of the measured signals present also a good compliance with that measured in reality when the tip resistance is qualitatively similar.

  9. Stress Transmission in Granular Packings: Localization and Cooperative Response

    Science.gov (United States)

    Ramola, Kabir

    We develop a framework for stress transmission in two dimensional granular media that respects vector force balance at the microscopic level. For a packing of grains interacting via pairwise contact forces, we introduce local gauge degrees of freedom that determine the response of the system to external perturbations. This allows us to construct unique force-balanced solutions that determine the change in contact forces as a response to external stress. By mapping this response to diffusion in the underlying contact network, we show that this naturally leads to spatial localization of forces. We present numerical evidence for stress localization using exact diagonalization studies of network Laplacians associated with soft disk packings. We use this formalism to characterize the deviation from elastic behaviour as the amount of disorder in the underlying network is varied. We discuss generalizations to systems with large friction between grains and other networks that display topological disorder. This work has been supported by NSF-DMR 1409093 and the W. M. Keck Foundation.

  10. Density-Driven segregation in Binary and Ternary Granular Systems

    NARCIS (Netherlands)

    Windows-Yule, Kit; Parker, David

    2015-01-01

    We present a first experimental study of density-induced segregation within a three-dimensional, vibrofluidised, ternary granular system. Using Positron Emission Particle Tracking (PEPT), we study the steady-state particle distributions achieved by binary and ternary granular beds under a variety of

  11. Digital media ethics

    DEFF Research Database (Denmark)

    Ess, Charles

    Designed as both a teaching text and reader for students and faculty across diverse disciplines, the book provides an "ethical toolkit" - an introduction to prevailing ethical frameworks - and shows their application to both general issues and specific case-studies in digital media (privacy...

  12. Mass Media in the Classroom.

    Science.gov (United States)

    Firth, Brian

    The teacher is provided with a range of practical suggestions for teaching about mass media. Chapters are devoted to the press, magazines, television, advertising, and film. The author argues that the teacher must start from the place of the various media in the lives of the children and not from a desire to instruct the children as to what they…

  13. Event-based user classification in Weibo media.

    Science.gov (United States)

    Guo, Liang; Wang, Wendong; Cheng, Shiduan; Que, Xirong

    2014-01-01

    Weibo media, known as the real-time microblogging services, has attracted massive attention and support from social network users. Weibo platform offers an opportunity for people to access information and changes the way people acquire and disseminate information significantly. Meanwhile, it enables people to respond to the social events in a more convenient way. Much of the information in Weibo media is related to some events. Users who post different contents, and exert different behavior or attitude may lead to different contribution to the specific event. Therefore, classifying the large amount of uncategorized social circles generated in Weibo media automatically from the perspective of events has been a promising task. Under this circumstance, in order to effectively organize and manage the huge amounts of users, thereby further managing their contents, we address the task of user classification in a more granular, event-based approach in this paper. By analyzing real data collected from Sina Weibo, we investigate the Weibo properties and utilize both content information and social network information to classify the numerous users into four primary groups: celebrities, organizations/media accounts, grassroots stars, and ordinary individuals. The experiments results show that our method identifies the user categories accurately.

  14. SMIL and SVG in teaching

    Science.gov (United States)

    Eidenberger, Horst

    2003-12-01

    This paper describes how the web standards Synchronized Multimedia Integration Language (SMIL) and Scalable Vector Graphics (SVG) are used in teaching at the Vienna University of Technology. SMIL and SVG are used in courses on multimedia authoring. Didactically, the goal is to teach students how to use media objects and timing concepts to build interactive media applications. Additionally, SMIL is applied to generate multimedia content from a database using a content management system. The paper gives background information on the SMIL and SVG standards and sketches how teaching multimedia is organized at the Vienna University of Technology. Courses from the summer term 2003 are described and illustrated in two case studies. General design problems of SMIL-based presentations are modelled as patterns. Additionally, suggestions for improvement in the standards are given and shortcomings of existing user agents are summarized. Our conclusion is that SMIL and SVG are very well suited for teaching multimedia. Currently, the main problem is that all existing SMIL players lack some properties desired for teaching applications (stability, correctness, etc.).

  15. Massive granular cell ameloblastoma with dural extension and atypical morphology

    Directory of Open Access Journals (Sweden)

    Vandana Raghunath

    2014-01-01

    Full Text Available Ameloblastomas are rare histologically benign, locally aggressive tumors arising from the oral ectoderm that occasionally reach a gigantic size. Giant ameloblastomas are a rarity these days with the advent of panoramic radiography in routine dental practice. Furthermore, the granular cell variant is an uncommon histological subtype of ameloblastoma where the central stellate reticulum like cells in tumor follicles is replaced by granular cells. Although granular cell ameloblastoma (GCA is considered to be a destructive tumor with a high recurrence rate, the significance of granular cells in predicting its biologic behavior is debatable. However, we present a rare case of giant GCA of remarkable histomorphology showing extensive craniofacial involvement and dural extension that rendered a good prognosis following treatment.

  16. Social Media in Educational Practice: Faculty Present and Future Use of Social Media in Teaching

    NARCIS (Netherlands)

    Esteve Del Valle, Marc; Gruzd, Anatoliy; Haythornthwaite, Caroline; Paulin, Drew; Gilbert, Sarah

    2017-01-01

    This paper presents results from a questionnaire (n=333) designed to gain an understanding of instructor motivations and experience with social media use in educational practice. Data on overall use of social media, and instructors’ use of social media in classes are applied to assess factors

  17. Teaching Blended Content Analysis and Critically Vigilant Media Consumption

    Science.gov (United States)

    Harris, Christopher S.

    2015-01-01

    The semester-long activity described herein uses an integrated instructional approach to media studies to introduce students to the research method of qualitative content analysis and help them become more critically vigilant media consumers. The goal is to increase students' media literacy by guiding them in the design of an exploratory…

  18. Tunneling magnetoresistance in granular cermet films with particle size distribution

    International Nuclear Information System (INIS)

    Vovk, A.Ya.; Golub, V.O.; Malkinski, L.; Kravets, A.F.; Pogorily, A.M.; Shypil', O.V.

    2004-01-01

    The correlation between tunneling magnetoresistance (TMR) and field sensitivity (dMR/dH) for granular films (Co 50 Fe 50 ) x -(Al 2 O 3 ) 1-x was studied. The position of TMR maximum is shifted towards the lower x in the higher applied magnetic fields. Such a behavior was observed for metal granular nanocomposites but is first reported for granular cermets. However the highest dMR/dH was found for the compositions just below the percolation threshold

  19. Influence of granular strontium chloride as additives on some ...

    Indian Academy of Sciences (India)

    Influence of granular strontium chloride as additives on some electrical and mechanical properties for pure polyvinyl alcohol. A B Elaydy M Hafez ... Keywords. Polyvinyl-alcohol (PVA); granular strontium chloride, SrCl2; a.c. electrical conductivity; dielectric constant; dielectric loss; Young's modulus; creep relaxation curve.

  20. On the Innovative Teaching Mode of Models in the Per-spective of Social Media%社会化媒体视阈中模特人才培养的创新教学模式研究

    Institute of Scientific and Technical Information of China (English)

    黄小熳; 谢小娜

    2015-01-01

    The rise of social media has a positive influence on the professional skill training and the theoretical knowledge access-ing in the teaching process of models. Social media provides rich fashion show material and the fashion market dynamic informa-tion to help complete models' performance skills demonstration and simulation. In terms of the theoretical knowledge accessing, social media makes the fashion information flow quickly, the knowledge disseminate diversely, the theoretical study become vividly. Therefore, social media makes the models' teaching mode into the digital teaching, interactive teaching, hybrid teaching and ubiquitous teaching. In the end, this paper constructed a models' teaching social media platform, which helps to regulate social media in the application of the models' professional training.%社会化媒体的兴起,对模特人才培养教学过程中专业技能训练与理论知识传授产生了积极的影响。在专业技能训练方面,社会化媒体为模特教学提供了丰富的时尚表演素材与市场动态资讯,帮助完成模特表演技能的演示与模拟,实现动作定向———参与性练习———自主练习———技能迁移的全过程;在理论知识传授方面,社会化媒体使时尚信息的流通快速化、获取知识的途径多元化、理论学习的方式生动化。因此,社会化媒体使模特专业的教学模式转变为数字化教学、交互性教学、混合式教学与泛在教学。最终,建构起模特专业教学的社会化媒体平台,规范社会化媒体在模特专业素养培养中的应用。

  1. Wet granular matter a truly complex fluid

    CERN Document Server

    Herminghaus, Stephan

    2013-01-01

    This is a monograph written for the young and advanced researcher who is entering the field of wet granular matter and keen to understand the basic physical principles governing this state of soft matter. It treats wet granulates as an instance of a ternary system, consisting of the grains, a primary, and a secondary fluid. After addressing wetting phenomena in general and outlining the basic facts on dry granular systems, a chapter on basic mechanisms and their effects is dedicated to every region of the ternary phase diagram. Effects of grain shape and roughness are considered as well. Rather than addressing engineering aspects such as existing books on this topic do, the book aims to provide a generalized framework suitable for those who want to understand these systems on a more fundamental basis. Readership: For the young and advanced researcher entering the field of wet granular matter.

  2. Evaluating the effects of granular and membrane filtrations on chlorine demand in drinking water.

    Science.gov (United States)

    Jegatheesan, Veeriah; Kim, Seung Hyun; Joo, C K; Gao, Baoyu

    2009-01-01

    In this study, chlorine decay experiments were conducted for the raw water from Nakdong River that is treated by Chilseo Water Treatment Plant (CWTP) situated in Haman, Korea as well as the effluents from sand and granular activated carbon (GAC) filters of CWTP and fitted using a chlorine decay model. The model estimated the fast and slow reacting nitrogenous as well as organic/inorganic compounds that were present in the water. It was found that the chlorine demand due to fast and slow reacting (FRA and SRA) organic/inorganic substances was not reduced significantly by sand as well as GAC filters. However, the treated effluents from those filters contained FRA and SRA that are less reactive and had small reaction rate constants. For the effluents from microfiltration, ultrafiltration, and nanofiltration the chlorine demand because FRA and SRA were further reduced but the reaction rate constants were larger compared to those of sand and GAC filter effluents. This has implications in the formation of disinfection by products (DBPs). If DBPs are assumed to form due to the interactions between chlorine and SRA, then it is possible that the DBP formation potential in the effluents from membrane filtrations could be higher than that in the effluents from granular media filters.

  3. Origin of the resistivity minima in granular superconductors

    International Nuclear Information System (INIS)

    Simanek, E.

    1982-01-01

    The recently observed minima in the temperature dependence of the electrical resistivity of a granular superconductor are explained with use of a percolation model of a disordered granular array, which takes into account the electrostatic charging energy. The thermally activated tunneling of Cooper pairs is shown to play an important role in the interpretation of the experimental data on tin films

  4. Hierarchical modular granular neural networks with fuzzy aggregation

    CERN Document Server

    Sanchez, Daniela

    2016-01-01

    In this book, a new method for hybrid intelligent systems is proposed. The proposed method is based on a granular computing approach applied in two levels. The techniques used and combined in the proposed method are modular neural networks (MNNs) with a Granular Computing (GrC) approach, thus resulting in a new concept of MNNs; modular granular neural networks (MGNNs). In addition fuzzy logic (FL) and hierarchical genetic algorithms (HGAs) are techniques used in this research work to improve results. These techniques are chosen because in other works have demonstrated to be a good option, and in the case of MNNs and HGAs, these techniques allow to improve the results obtained than with their conventional versions; respectively artificial neural networks and genetic algorithms.

  5. Surface effects in the acetylation of granular potato starch

    NARCIS (Netherlands)

    Steeneken, P.A.M.; Woortman, A.J.J.

    2008-01-01

    The occurrence of surface effects in the acetylation of granular potato starch with acetic anhydride to degrees of substitution 0.04-0.2 was studied by two different approaches. The first approach involved the fractionation of granular starch acetates into five different size classes and analysis of

  6. Improve Outcomes Study subjects Chemistry Teaching and Learning Strategies through independent study with the help of computer-based media

    Science.gov (United States)

    Sugiharti, Gulmah

    2018-03-01

    This study aims to see the improvement of student learning outcomes by independent learning using computer-based learning media in the course of STBM (Teaching and Learning Strategy) Chemistry. Population in this research all student of class of 2014 which take subject STBM Chemistry as many as 4 class. While the sample is taken by purposive as many as 2 classes, each 32 students, as control class and expriment class. The instrument used is the test of learning outcomes in the form of multiple choice with the number of questions as many as 20 questions that have been declared valid, and reliable. Data analysis techniques used one-sided t test and improved learning outcomes using a normalized gain test. Based on the learning result data, the average of normalized gain values for the experimental class is 0,530 and for the control class is 0,224. The result of the experimental student learning result is 53% and the control class is 22,4%. Hypothesis testing results obtained t count> ttable is 9.02> 1.6723 at the level of significance α = 0.05 and db = 58. This means that the acceptance of Ha is the use of computer-based learning media (CAI Computer) can improve student learning outcomes in the course Learning Teaching Strategy (STBM) Chemistry academic year 2017/2018.

  7. Cohesive granular media modelization with non-convex particles shape: Application to UO2 powder compaction

    International Nuclear Information System (INIS)

    Saint-Cyr, B.

    2011-01-01

    We model in this work granular materials composed of non-convex and cohesive aggregates, in view of application to the rheology of UO 2 powders. The effect of non convexity is analyzed in terms of bulk quantities (Coulomb internal friction and cohesion) and micromechanical parameters such as texture anisotropy and force transmission. In particular, we find that the packing fraction evolves in a complex manner with the shape non convexity and the shear strength increases but saturates due to interlocking between the aggregates. We introduce simple models to describe these features in terms of micro-mechanical parameters. Furthermore, a systematic investigation of shearing, uniaxial compaction and simple compression of cohesive packings show that bulk cohesion increases with non-convexity but is strongly influenced by the boundary conditions and shear bands or stress concentration. (author) [fr

  8. DAKWAH ISLAM DAN INOVASI MEDIA: PELUANG DAN ANCAMAN MEDIA GLOBAL ATAS DAKWAH ISLAM

    OpenAIRE

    Moch. Fakhruroji

    2015-01-01

    The development of dakwah science is not as fast as the development of dakwah activities. In this global society, dakwah activities can even be found in the world wide web. They transform greatly in public space as spiritual teachings and are actualized in various forms. These various forms of dakwah activities are supported by dakwah media. In dakwah science, media becomes a channel used by the agents of dakwah activities to deliver the messages

  9. Teaching Tweeting: Recommendations for Teaching Social Media Work in LIS and MSIS Programs

    Science.gov (United States)

    Simons, Rachel N.; Ocepek, Melissa G.; Barker, Lecia J.

    2016-01-01

    A combination of public relations, marketing, advertising, and information and communication technologies, social media work is an increasingly important part of information professionals' jobs. This paper reports on a survey-based study of 49 information professionals who routinely use social media in their work. Respondents provided information…

  10. Tuning strain of granular matter by basal assisted Couette shear

    Directory of Open Access Journals (Sweden)

    Zhao Yiqiu

    2017-01-01

    Full Text Available We present a novel Couette shear apparatus capable of generating programmable azimuthal strain inside 2D granular matter under Couette shear. The apparatus consists of 21 independently movable concentric rings and two boundary wheels with frictional racks. This makes it possible to quasistatically shear the granular matter not only from the boundaries but also from the bottom. We show that, by specifying the collective motion of wheels and rings, the apparatus successfully generates the desired strain profile inside the sample granular system, which is composed of about 2000 photoelastic disks. The motion and stress of each particle is captured by an imaging system utilizing reflective photoelasticimetry. This apparatus provides a novel method to investigate shear jamming properties of granular matter with different interior strain profiles and unlimited strain amplitudes.

  11. Social Media in Surgical Training: Opportunities and Risks.

    Science.gov (United States)

    Ovaere, Sander; Zimmerman, David D E; Brady, Richard R

    2018-05-02

    Surgeon engagement with social media is growing rapidly. Innovative applications in diverse fields of health care are increasingly available. The aim of this review is to explore the current and future applications of social media in surgical training. In addition, risks and barriers of social media engagement are analyzed, and recommendations for professional social media use amongst trainers and trainees are suggested. The published, peer-reviewed literature on social media in medicine, surgery and surgical training was reviewed. MESH terms including "social media", "education", "surgical training" and "web applications" were used. Different social media surgical applications are already widely available but limited in use in the trainee's curriculum. E-learning modalities, podcasts, live surgery platforms and microblogs are used for teaching purposes. Social media enables global research collaboratives and can play a role in patient recruitment for clinical trials. The growing importance of networking is emphasized by the increased use of LinkedIn, Facebook, Sermo and other networking platforms. Risks of social media use, such as lack of peer review and the lack of source confirmation, must be considered. Governing surgeon's and trainee's associations should consider adopting and sharing their guidelines for standards of social media use. Surgical training is changing rapidly and as such, social media presents tremendous opportunities for teaching, training, research and networking. Awareness must be raised on the risks of social media use. Copyright © 2018 Association of Program Directors in Surgery. All rights reserved.

  12. Media Literacy for the 21st Century. A Response to "The Need for Media Education in Democratic Education"

    Science.gov (United States)

    Levine, Peter

    2015-01-01

    We cannot pretend to educate young people for citizenship and political participation without teaching them to understand and use the new media, which are essential means of expressing ideas, forming public opinions, and building institutions and movements. But the challenge of media literacy education is serious. Students need advanced and…

  13. Emotional Granularity Effects on Event-Related Brain Potentials during Affective Picture Processing.

    Science.gov (United States)

    Lee, Ja Y; Lindquist, Kristen A; Nam, Chang S

    2017-01-01

    There is debate about whether emotional granularity , the tendency to label emotions in a nuanced and specific manner, is merely a product of labeling abilities, or a systematic difference in the experience of emotion during emotionally evocative events. According to the Conceptual Act Theory of Emotion (CAT) (Barrett, 2006), emotional granularity is due to the latter and is a product of on-going temporal differences in how individuals categorize and thus make meaning of their affective states. To address this question, the present study investigated the effects of individual differences in emotional granularity on electroencephalography-based brain activity during the experience of emotion in response to affective images. Event-related potentials (ERP) and event-related desynchronization and synchronization (ERD/ERS) analysis techniques were used. We found that ERP responses during the very early (60-90 ms), middle (270-300 ms), and later (540-570 ms) moments of stimulus presentation were associated with individuals' level of granularity. We also observed that highly granular individuals, compared to lowly granular individuals, exhibited relatively stable desynchronization of alpha power (8-12 Hz) and synchronization of gamma power (30-50 Hz) during the 3 s of stimulus presentation. Overall, our results suggest that emotional granularity is related to differences in neural processing throughout emotional experiences and that high granularity could be associated with access to executive control resources and a more habitual processing of affective stimuli, or a kind of "emotional complexity." Implications for models of emotion are also discussed.

  14. Drama, Media Advertising, and Inner-City Youth.

    Science.gov (United States)

    Conrad, Diane

    2002-01-01

    Describes a reflective practice case study which involved creating and delivering a unit integrating drama, media literacy, and media production with a focus on advertising for a group of students at an alternative inner-city high school. Proposes this strategy may assist others in studies and teaching practice. (PM)

  15. Small solar system bodies as granular systems

    Science.gov (United States)

    Hestroffer, Daniel; Campo Bagatín, Adriano; Losert, Wolfgang; Opsomer, Eric; Sánchez, Paul; Scheeres, Daniel J.; Staron, Lydie; Taberlet, Nicolas; Yano, Hajime; Eggl, Siegfried; Lecomte, Charles-Edouard; Murdoch, Naomi; Radjai, Fahrang; Richardson, Derek C.; Salazar, Marcos; Schwartz, Stephen R.; Tanga, Paolo

    2017-06-01

    Asteroids and other Small Solar System Bodies (SSSBs) are currently of great scientific and even industrial interest. Asteroids exist as the permanent record of the formation of the Solar System and therefore hold many clues to its understanding as a whole, as well as insights into the formation of planetary bodies. Additionally, SSSBs are being investigated in the context of impact risks for the Earth, space situational awareness and their possible industrial exploitation (asteroid mining). In all these aspects, the knowledge of the geophysical characteristics of SSSB surface and internal structure are of great importance. Given their size, constitution, and the evidence that many SSSBs are not simple monoliths, these bodies should be studied and modelled as self-gravitating granular systems in general, or as granular systems in micro-gravity environments in particular contexts. As such, the study of the geophysical characteristics of SSSBs is a multi-disciplinary effort that lies at the crossroads between Granular Mechanics, Celestial Mechanics, Soil Mechanics, Aerospace Engineering and Computer Sciences.

  16. The Development of Media Literacy among Grade Five Teachers and Students - A Case Study

    Directory of Open Access Journals (Sweden)

    Rachel McCabe

    2008-03-01

    Full Text Available This is the first of two articles about a study of the implementation of a media literacy curriculum project in three inner city school Grade 5's in Montreal. The authors describe what the teachers and students learned about two key Media Literacy concepts: the media construct reality and audiences negotiate the meanings of media texts. The teaching featured the use of Internet and computer technology. Their findings suggest that it is possible to teach elementary students to read media critically and raises some issues that merit further investigation: the ideology of positivism that permeates the use of technology in education; the training of media education teachers; and the factors that characterize effective media education pedagogy.

  17. Thermal diffusion segregation of an impurity in a driven granular fluid

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, Francisco Vega; Garzó, Vicente [Departamento de Física, Universidad de Extremadura, E-06071 Badajoz, Spain and Instituto de Computación Científica Avanzada (ICCAEx), Universidad de Extremadura, E-06071 Badajoz (Spain)

    2014-12-09

    We study segregation of an impurity in a driven granular fluid under two types of steady states. In the first state, the granular gas is driven by a stochastic volume force field with a Fourier-type profile while in the second state, the granular gas is sheared in such a way that inelastic cooling is balanced by viscous heating. We compare theoretical results derived from a solution of the (inelastic) Boltzmann equation at Navier-Stokes (NS) order with those obtained from the Direct Monte Carlo simulation (DSMC) method and molecular dynamics (MD) simulations. Good agreement is found between theory and simulation, which provides strong evidence of the reliability of NS granular hydrodynamics for these steady states (including the dynamics of the impurity), even at high inelasticity. In addition, preliminary results for thermal diffusion in granular fluids at moderate densities are also presented. As for dilute gases, excellent agreement is also found in this more general case.

  18. First-Year Composition Teachers' Uses of New Media Technologies in the Composition Class

    Science.gov (United States)

    Mina, Lilian W.

    2014-01-01

    As new media technologies emerge and evolve rapidly, the need to make informed decisions about using these technologies in teaching writing increases. This dissertation research study aimed at achieving multiple purposes. The first purpose was to catalog the new media technologies writing teachers use in teaching first-year composition classes.…

  19. Electrical transport properties in Fe-Cr nanocluster-assembled granular films

    Science.gov (United States)

    Wang, Xiong-Zhi; Wang, Lai-Sen; Zhang, Qin-Fu; Liu, Xiang; Xie, Jia; Su, A.-Mei; Zheng, Hong-Fei; Peng, Dong-Liang

    2017-09-01

    The Fe100-xCrx nanocluster-assembled granular films with Cr atomic fraction (x) ranging from 0 to 100 were fabricated by using a plasma-gas-condensation cluster deposition system. The TEM characterization revealed that the uniform Fe clusters were coated with a Cr layer to form a Fe-Cr core-shell structure. Then, the as-prepared Fe100-xCrx nanoclusters were randomly assembled into a granular film in vacuum environments with increasing the deposition time. Because of the competition between interfacial resistance and shunting effect of Cr layer, the room temperature resistivity of the Fe100-xCrx nanocluster-assembled granular films first increased and then decreased with increasing the Cr atomic fraction (x), and revealed a maximum of 2 × 104 μΩ cm at x = 26 at.%. The temperature-dependent longitudinal resistivity (ρxx), magnetoresistance (MR) effect and anomalous Hall effect (AHE) of these Fe100-xCrx nanocluster-assembled granular films were also studied systematically. As the x increased from 0 to 100, the ρxx of all samples firstly decreased and then increased with increasing the measuring temperature. The dependence of ρxx on temperature could be well addressed by a mechanism incorporated for the fluctuation-induced-tunneling (FIT) conduction process and temperature-dependent scattering effect. It was found that the anomalous Hall effect (AHE) had no legible scaling relation in Fe100-xCrx nanocluster-assembled granular films. However, after deducting the contribution of tunneling effect, the scaling relation was unambiguous. Additionally, the Fe100-xCrx nanocluster-assembled granular films revealed a small negative magnetoresistance (MR), which decreased with the increase of x. The detailed physical mechanism of the electrical transport properties in these Fe100-xCrx nanocluster-assembled granular films was also studied.

  20. Digital Technology and Teacher Preparation: The Instructional Role of Social Media Among Pre-Service Teachers

    Science.gov (United States)

    Trytten, Bria Klotz

    As social media use becomes more prevalent among teachers, it becomes vital to understand how teachers are using social media and what effects it has, if any, on teaching practices in the classroom. This study sought to explore the relationship between pre-service teachers' use of social media and their perceptions of inquiry-based science education, an important teaching best practice. This study is unique in that it explores pre-service teachers' use of three social media platforms--Twitter, Facebook, and Pinterest--and how pre-service teachers plan to apply them to classroom education. Previous studies focused on only one social media platform, usually Twitter or Facebook. This study surveyed 113 pre-service teachers in their 3rd or 4th year of school at one of two teacher colleges. The survey employed multiple choice, open-ended, and Likert-type questions to assess pre-service teachers' use of social media as well as their attitudes surrounding inquiry-based instruction. In order to better explain and analyze survey results, fourteen survey participants were interviewed with follow-up questions to elaborate on both social media use and inquiry attitudes. Findings indicated that the pre-service teachers used social media, and overwhelmingly Pinterest, to find lesson plans and classroom organizational ideas. Cited reasons for this practice included convenience, variety of lesson planning, and easily searchable databases. The study found statistical significance in that teachers who aspire to teach lower grade levels will turn to social media to find lesson plans more frequently than those who aspire to teach higher grade levels. The study found social media use had no statistically significant effect on the level of inquiry-based teaching that the participants aimed to achieve in their future classrooms.

  1. Dermatofibroma-like granular cell tumour: a potential diagnostic pitfall

    Directory of Open Access Journals (Sweden)

    Jiri Soukup

    2016-11-01

    Full Text Available Dermatofibroma-like granular cell tumour (GCT is a rare entity, with only two cases having been described so far. We report another case in a 62-year-old woman, discuss histopathological features, and review other tumours in which granular changes have been observed. Our tumour was composed predominantly of oval-to-spindle granular cells with prominent nucleoli, arranged in short fascicles and storiform pattern, infiltrating around collagen bundles. Immunohistochemical analysis with antibodies against CD31, CD56, CD68, CD117, S-100 protein, inhibin, calretinin, EMA, p53 and MIB-1 was performed, showing expression of CD56, CD68, S-100 protein, inhibin and calretinin. The diagnosis of atypical dermatofibroma-like GCT was made.

  2. Characteristics and performance of aerobic algae-bacteria granular consortia in a photo-sequencing batch reactor.

    Science.gov (United States)

    Liu, Lin; Zeng, Zhichao; Bee, Mingyang; Gibson, Valerie; Wei, Lili; Huang, Xu; Liu, Chaoxiang

    2018-05-05

    The characteristics and performance of algae-bacteria granular consortia which cultivated with aerobic granules and targeted algae (Chlorella and Scenedesmus), and the essential difference between granular consortia and aerobic granules were investigated in this experiment. The result indicated that algae-bacteria granular consortia could be successfully developed, and the algae present in the granular consortia were mainly Chlorella and Scenedesmus. Although the change of chlorophyll composition revealed the occurrence of light limitation for algal growth, the granular consortia could maintain stable granular structure, and even showed better settling property than aerobic granules. Total nitrogen and phosphate in the algal-bacterial granular system showed better removal efficiencies (50.2% and 35.7%) than those in the aerobic granular system (32.8% and 25.6%) within one cycle (6 h). The biodiesel yield of aerobic granules could be significantly improved by algal coupled process, yet methyl linolenate and methyl palmitoleate were the dominant composition of biodiesel obtained from granular consortia and aerobic granules, respectively. Meanwhile, the difference of dominant bacterial communities in the both granules was found at the order level and family level, and alpha diversity indexes revealed the granular consortia had a higher microbial diversity. Copyright © 2018. Published by Elsevier B.V.

  3. User-centric Query Refinement and Processing Using Granularity Based Strategies

    NARCIS (Netherlands)

    Zeng, Y.; Zhong, N.; Wang, Y.; Qin, Y.; Huang, Z.; Zhou, H; Yao, Y; van Harmelen, F.A.H.

    2011-01-01

    Under the context of large-scale scientific literatures, this paper provides a user-centric approach for refining and processing incomplete or vague query based on cognitive- and granularity-based strategies. From the viewpoints of user interests retention and granular information processing, we

  4. Large mid-esophageal granular cell tumor: benign versus malignant

    Directory of Open Access Journals (Sweden)

    Prarthana Roselil Christopher

    2015-06-01

    Full Text Available Granular cell tumors are rare soft tissue neoplasms, among which only 2% are malignant, arising from nervous tissue. Here we present a case of a large esophageal granular cell tumor with benign histopathological features which metastasized to the liver, but showing on positron emission tomography-computerized tomography standardized uptake value suggestive of a benign lesion.

  5. Adsorption Study of Cobalt on Treated Granular Activated Carbon

    OpenAIRE

    Y. V. Hete; S. B. Gholase; R. U. Khope

    2012-01-01

    This study is carried out for the removal of cobalt from aqueous solution using granular activated carbon in combination with p-nitro benzoic acid at temperature 25±1 °C. The adsorption isotherm of cobalt on granular activated carbon has been determined and the data fitted reasonably well to the Langmuir and Freundlich isotherm for activated carbon.

  6. Swelling pressure and water absorption property of compacted granular bentonite during water absorption

    International Nuclear Information System (INIS)

    Oyamada, T.; Komine, H.; Murakami, S.; Sekiguchi, T.; Sekine, I.

    2012-01-01

    Document available in extended abstract form only. Bentonite is currently planned to be used as buffer materials in engineered barrier of radioactive waste disposal. Granular bentonites are expected as the materials used in constructions as buffer materials by in-situ compaction methods. After applying these buffer materials, it is expected that the condition of the buffer area changes in long-term by the seepage of groundwater into buffer area. Therefore, it is important to understand water movement and swelling behavior of the buffer materials for evaluating the performance of engineered barrier. In this study, we investigated water absorption property and swelling pressure of compacted granular bentonite. Specifically, the process of swelling pressure and amount of water absorption of granular bentonite-GX (Kunigel-GX, produced at the Tsukinuno mine in Japan) were observed by laboratory tests. To discuss the influence of maximum grain size of bentonite particle on swelling pressure and water absorption property, two types of samples were used. One is granular sample which is Bentonite-GX controlled under 2 mm the maximum grain size, the other is milled sample which is Bentonite-GX with the maximum grain size under 0.18 mm by milling with the agate mortar. In addition, the mechanism on the swelling pressure of compacted granular bentonite was considered and discussed. In the cases of granular sample, swelling pressure increases rapidly, then gradually continues to increase up to maximum value. In the cases of milled sample, swelling pressure also increases rapidly at first. However, then its value decreases before progressing of gradual increase continues. Especially, this trend was clearly observed at a relatively low dry density. At the peaks of these curves, the swelling pressure of granular samples is lower than that of milled samples. In addition, the increasing of swelling pressure by the time the peak observed during the process of swelling pressure from

  7. Social media in higher education: A look at participatory culture in graduate coursework

    Directory of Open Access Journals (Sweden)

    Ann-Louise Davidson

    2013-01-01

    Full Text Available Society has become fascinated with web- based social media. Recently, aspects of social media environments such as participatory culture, new media digital literacies, and connectivism have been increasingly investigated. However, current university policies often restrict, if not forbid, the use of social networking sites in class. For professors seeking to introduce social media into their teaching practice, these restrictive policies can make it difficult to teach with and about social computing and computer-supported collaborative work. This descriptive paper presents the experiences of two professors who integrated Web 2.0 practices into their respective graduate-level education courses titled Social Computing and Computer-Supported Collaborative Work and Web 2.0 = Pedagogy 2.0? and describes their underlying theories and concepts. Subsequently, the courses’ rationales theoretical underpinnings, and teaching approaches are delineated, and implementation strategies are suggested.

  8. Editorial: Modelling and computational challenges in granular materials

    OpenAIRE

    Weinhart, Thomas; Thornton, Anthony Richard; Einav, Itai

    2015-01-01

    This is the editorial for the special issue on “Modelling and computational challenges in granular materials” in the journal on Computational Particle Mechanics (CPM). The issue aims to provide an opportunity for physicists, engineers, applied mathematicians and computational scientists to discuss the current progress and latest advancements in the field of advanced numerical methods and modelling of granular materials. The focus will be on computational methods, improved algorithms and the m...

  9. Can one ``Hear'' the aggregation state of a granular system?

    Science.gov (United States)

    Kruelle, Christof A.; Sánchez, Almudena García

    2013-06-01

    If an ensemble of macroscopic particles is mechanically agitated the constant energy input is dissipated into the system by multiple inelastic collisions. As a result, the granular material can exhibit, depending on the magnitude of agitation, several physical states - like a gaseous phase for high energy input or a condensed state for low agitation. Here we introduce a new method for quantifying the acoustical response of the granular system. Our experimental system consists of a monodisperse packing of glass beads with a free upper surface, which is confined inside a cylindrical container. An electro-mechanical shaker exerts a sinusoidal vertical vibration at normalized accelerations well above the fluidization threshold for a monolayer of particles. By increasing the number of beads the granular gas suddenly collapses if a critical threshold is exceeded. The transition can be detected easily with a microphone connected to the soundcard of a PC. From the recorded audio track a FFT is calculated in real-time. Depending on either the number of particles at a fixed acceleration or the amount of energy input for a given number of particles, the resulting rattling noise exhibits a power spectrum with either the dominating (shaker) frequency plus higher harmonics for a granular crystal or a high-frequency broad-band noise for a granular gas, respectively. Our new method demonstrates that it is possible to quantify analytically the subjective audio impressions of a careful listener and thus to distinguish easily between different aggregation states of an excited granular system.

  10. Granular-front formation in free-surface flow of concentrated suspensions

    Science.gov (United States)

    Leonardi, Alessandro; Cabrera, Miguel; Wittel, Falk K.; Kaitna, Roland; Mendoza, Miller; Wu, Wei; Herrmann, Hans J.

    2015-11-01

    A granular front emerges whenever the free-surface flow of a concentrated suspension spontaneously alters its internal structure, exhibiting a higher concentration of particles close to its front. This is a common and yet unexplained phenomenon, which is usually believed to be the result of fluid convection in combination with particle size segregation. However, suspensions composed of uniformly sized particles also develop a granular front. Within a large rotating drum, a stationary recirculating avalanche is generated. The flowing material is a mixture of a viscoplastic fluid obtained from a kaolin-water dispersion with spherical ceramic particles denser than the fluid. The goal is to mimic the composition of many common granular-fluid materials, such as fresh concrete or debris flow. In these materials, granular and fluid phases have the natural tendency to separate due to particle settling. However, through the shearing caused by the rotation of the drum, a reorganization of the phases is induced, leading to the formation of a granular front. By tuning the particle concentration and the drum velocity, it is possible to control this phenomenon. The setting is reproduced in a numerical environment, where the fluid is solved by a lattice-Boltzmann method, and the particles are explicitly represented using the discrete element method. The simulations confirm the findings of the experiments, and provide insight into the internal mechanisms. Comparing the time scale of particle settling with the one of particle recirculation, a nondimensional number is defined, and is found to be effective in predicting the formation of a granular front.

  11. Numerical and experimental approaches to study soil transport and clogging in granular filters

    Science.gov (United States)

    Kanarska, Y.; Smith, J. J.; Ezzedine, S. M.; Lomov, I.; Glascoe, L. G.

    2012-12-01

    Failure of a dam by erosion ranks among the most serious accidents in civil engineering. The best way to prevent internal erosion is using adequate granular filters in the transition areas where important hydraulic gradients can appear. In case of cracking and erosion, if the filter is capable of retaining the eroded particles, the crack will seal and the dam safety will be ensured. Numerical modeling has proved to be a cost-effective tool for improving our understanding of physical processes. Traditionally, the consideration of flow and particle transport in porous media has focused on treating the media as continuum. Practical models typically address flow and transport based on the Darcy's law as a function of a pressure gradient and a medium-dependent permeability parameter. Additional macroscopic constitutes describe porosity, and permeability changes during the migration of a suspension through porous media. However, most of them rely on empirical correlations, which often need to be recalibrated for each application. Grain-scale modeling can be used to gain insight into scale dependence of continuum macroscale parameters. A finite element numerical solution of the Navier-Stokes equations for fluid flow together with Lagrange multiplier technique for solid particles was applied to the simulation of soil filtration in the filter layers of gravity dam. The numerical approach was validated through comparison of numerical simulations with the experimental results of base soil particle clogging in the filter layers performed at ERDC. The numerical simulation correctly predicted flow and pressure decay due to particle clogging. The base soil particle distribution was almost identical to those measured in the laboratory experiment. It is believed that the agreement between simulations and experimental data demonstrates the applicability of the proposed approach for prediction of the soil transport and clogging in embankment dams. To get more precise understanding of

  12. Nonlinear instability and convection in a vertically vibrated granular bed

    NARCIS (Netherlands)

    Shukla, P.; Ansari, I.H.; van der Meer, Roger M.; Lohse, Detlef; Alam, M.

    2014-01-01

    The nonlinear instability of the density-inverted granular Leidenfrost state and the resulting convective motion in strongly shaken granular matter are analysed via a weakly nonlinear analysis of the hydrodynamic equations. The base state is assumed to be quasi-steady and the effect of harmonic

  13. Event-Based User Classification in Weibo Media

    Directory of Open Access Journals (Sweden)

    Liang Guo

    2014-01-01

    Full Text Available Weibo media, known as the real-time microblogging services, has attracted massive attention and support from social network users. Weibo platform offers an opportunity for people to access information and changes the way people acquire and disseminate information significantly. Meanwhile, it enables people to respond to the social events in a more convenient way. Much of the information in Weibo media is related to some events. Users who post different contents, and exert different behavior or attitude may lead to different contribution to the specific event. Therefore, classifying the large amount of uncategorized social circles generated in Weibo media automatically from the perspective of events has been a promising task. Under this circumstance, in order to effectively organize and manage the huge amounts of users, thereby further managing their contents, we address the task of user classification in a more granular, event-based approach in this paper. By analyzing real data collected from Sina Weibo, we investigate the Weibo properties and utilize both content information and social network information to classify the numerous users into four primary groups: celebrities, organizations/media accounts, grassroots stars, and ordinary individuals. The experiments results show that our method identifies the user categories accurately.

  14. Social Media Training for Professional Identity Development in Undergraduate Nurses.

    Science.gov (United States)

    Mather, Carey; Cummings, Elizabeth; Nichols, Linda

    2016-01-01

    The growth of social media use has led to tension affecting the perception of professionalism of nurses in healthcare environments. The aim of this cross-sectional study was to explore first and final year undergraduate student use of social media to understand how it was utilised by them during their course. Descriptive statistical analysis was undertaken to compare differences between first and final year student use. No difference indicated there was a lack of development in the use of social media, particularly concerning in relation to expanding their professional networks. There is a need for the curriculum to include opportunities to teach student nurses methods to ensure the appropriate and safe use of social media. Overt teaching and modelling of desired behaviour to guide and support the use of social media to positively promote professional identity formation, which is essential for work-readiness at graduation, is necessary.

  15. COMPORTAMIENTO RESILIENTE DE MATERIALES GRANULARES EN PAVIMENTOS FLEXIBLES: ESTADO DEL CONOCIMIENTO RESILIENT BEHAVIOR OF GRANULAR MATERIALS IN FLEXIBLE PAVEMENTS: STATE OF THE ART

    Directory of Open Access Journals (Sweden)

    Hugo Alexander Rondón Quintana

    2007-07-01

    Full Text Available Los vehículos que circulan sobre una estructura de pavimento inducen ciclos de carga y descarga que generan dentro de las capas granulares deformaciones recuperables (resilientes y permanentes (plásticas. La ingeniería de pavimentos ha venido desarrollando estudios desde la década de los 60 con el fin de intentar comprender el comportamiento elastoplástico que experimentan materiales granulares cuando conforman capas de base y subbase en estructuras flexibles. La mayor parte de las investigaciones que se han realizado en esta área se han concentrado en estudiar su comportamiento resiliente. El estado del conocimiento de estudios desarrollados para medir la respuesta resiliente y la deformación permanente en materiales granulares es presentado en dos artículos por separado. En este primer artículo se presenta la forma como ha sido estudiado el comportamiento resiliente de materiales granulares y se discuten los factores que influyen en dicho comportamiento. Al final del artículo se presenta la evolución de las ecuaciones matemáticas desarrolladas a partir de resultados de estudios teóricos y experimentales. Un estado del conocimiento sobre el fenómeno de deformación permanente es presentado en un segundo artículo.When vehicles move on a pavement structure, they induce load cycles that generate resilient and permanent strains inside granular layers. Since the 60's, pavement engineering has developed studies in order to understand the elasto-plastic behavior that granular materials experiment on base and sub-base layers of flexible pavements. Most of the researches that have been made in this area have concentrated in studying their resilient behavior. A state of the art about the behavior of granular materials in flexible pavements is presented in two separate papers. This first paper tries on resilient stress-strain characteristics of such materials. The mathematical equations found in the literature to predict the resilient

  16. Effective transport properties for the pyridine-granular activated carbon adsorption system

    Directory of Open Access Journals (Sweden)

    S. A. Baz-Rodríguez

    2012-09-01

    Full Text Available In this work, the kinetics of pyridine adsorption onto granular activated carbon was studied from the point of view of an up-scaling process by using the method of volume averaging. The pore and surface effective diffusivities were estimated by supposing simple microscale geometries (ordered media of cylinders and spheres and those of images processed from SEM (Scanning Electron Microscopy micrographs. In addition, as a rough estimate, the point surface diffusivity is reported. The results revealed that the up-scaled diffusional model satisfactorily interpreted the concentration decay curves and the effective diffusivity was found to be an increasing function of the concentration, mainly due to the contribution of surface diffusion. In general, the diffusivity coefficients involved in the adsorption system are related through the expression molecular diffusivity = 22 ï‚' point surface diffusivity = 5/2 x‚' pore effective diffusivity = 1/12 x ‚' surface effective diffusivity.

  17. Submammary Granular Parakeratosis Treated With Mastopexy.

    Science.gov (United States)

    Nelson, Garrett; Lien, Mary H; Messina, Jane L; Ranjit, Sonali; Fenske, Neil Alan

    2017-08-01

    Granular parakeratosis, originally named axillary granular parakeratosis, is an uncommon disease with an unclear etiology. It is thought to result from defective processing of profillagrin to fillagrin, causing retention of keratohyaline granules in the epidermis. A myriad of causative factors has been proposed, including friction, moisture, heat, and contact irritants such as deodorants. We present a case in the inframammary area that resolved with mastopexy, further supporting the role of friction, moisture, and heat. Furthermore, we present electron microscopic evidence demonstrating non-degraded keratohyaline granules upon epidermal maturation. This entity, we believe, is reactive and represents a protective response of the body to moisture and heat. J Drugs Dermatol. 2017;16(8):810-812..

  18. Tumor of granular cells of esophagus

    International Nuclear Information System (INIS)

    Gonzalez Fabian, Licet; Diaz Anaya, Amnia; Perez de la Torre, Georgina

    2010-01-01

    Granular cells tumors are rare and asymptomatic lesions and by general, it is an incidental finding en high or low endoscopy. They were described for the first time by Abrikossoff in 1926. The more frequent locations are the buccal mucosa, dermis and subcutaneous cellular tissue, most of these tumors has a benign origin. This is the case of a woman aged 44 with a pyrosis history from a year ago; by high endoscopy it is noted a 8 mm lesion distal to esophagus and confirmed by histological study of granular cells tumor. Elective treatment of this lesion is the endoscopic polypectomy. Despite that the malign potential is low; we suggested a close clinical and endoscopic follow-up.

  19. Traffic and Granular Flow ’07

    CERN Document Server

    Chevoir, François; Gondret, Philippe; Lassarre, Sylvain; Lebacque, Jean-Patrick; Schreckenberg, Michael

    2009-01-01

    This book covers several research fields, all of which deal with transport. Three main topics are treated: road traffic, granular matter, and biological transport. Different points of view, i.e. modelling, simulations, experiments, and phenomenological observations, are considered. Sub-topics include: highway or urban vehicular traffic (dynamics of traffic, macro/micro modelling, measurements, data analysis, security issues, psychological issues), pedestrian traffic, animal traffic (e.g. social insects), collective motion in biological systems (molecular motors...), granular flow (dense flows, intermittent flows, solid/liquid transition, jamming, force networks, fluid and solid friction), networks (biological networks, urban traffic, the internet, vulnerability of networks, optimal transport networks) and cellular automata applied to the various aforementioned fields.

  20. Navier-Stokes hydrodynamics of thermal collapse in a freely cooling granular gas.

    Science.gov (United States)

    Kolvin, Itamar; Livne, Eli; Meerson, Baruch

    2010-08-01

    We show that, in dimension higher than one, heat diffusion and viscosity cannot arrest thermal collapse in a freely evolving dilute granular gas, even in the absence of gravity. Thermal collapse involves a finite-time blowup of the gas density. It was predicted earlier in ideal, Euler hydrodynamics of dilute granular gases in the absence of gravity, and in nonideal, Navier-Stokes granular hydrodynamics in the presence of gravity. We determine, analytically and numerically, the dynamic scaling laws that characterize the gas flow close to collapse. We also investigate bifurcations of a freely evolving dilute granular gas in circular and wedge-shaped containers. Our results imply that, in general, thermal collapse can only be arrested when the gas density becomes comparable with the close-packing density of grains. This provides a natural explanation to the formation of densely packed clusters of particles in a variety of initially dilute granular flows.

  1. Failure evolution in granular material retained by rigid wall in active mode

    Science.gov (United States)

    Pietrzak, Magdalena; Leśniewska, Danuta

    2012-10-01

    This paper presents a detailed study of a selected small scale model test, performed on a sample of surrogate granular material, retained by a rigid wall (typical geotechnical problem of earth thrust on a retaining wall). The experimental data presented in this paper show that the deformation of granular sample behind retaining wall can undergo some cyclic changes. The nature of these cycles is not clear - it is probably related to some micromechanical features of granular materials, which are recently extensively studied in many research centers in the world. Employing very precise DIC (PIV) method can help to relate micro and macro-scale behavior of granular materials.

  2. Granular Leidenfrost effect: Experiment and theory of floating particle clusters

    NARCIS (Netherlands)

    Eshuis, Peter; Eshuis, P.G.; van der Meer, Roger M.; van der Weele, J.P.; Lohse, Detlef

    2005-01-01

    Granular material is vertically vibrated in a 2D container: above a critical shaking strength, and for a sufficient number of beads, a crystalline cluster is elevated and supported by a dilute gaseous layer of fast beads underneath. We call this phenomenon the granular Leidenfrost effect. The

  3. Adsorption Study of Cobalt on Treated Granular Activated Carbon

    Directory of Open Access Journals (Sweden)

    Y. V. Hete

    2012-01-01

    Full Text Available This study is carried out for the removal of cobalt from aqueous solution using granular activated carbon in combination with p-nitro benzoic acid at temperature 25±1 °C. The adsorption isotherm of cobalt on granular activated carbon has been determined and the data fitted reasonably well to the Langmuir and Freundlich isotherm for activated carbon.

  4. Granular computing in decision approximation an application of rough mereology

    CERN Document Server

    Polkowski, Lech

    2015-01-01

    This book presents a study in knowledge discovery in data with knowledge understood as a set of relations among objects and their properties. Relations in this case are implicative decision rules and the paradigm in which they are induced is that of computing with granules defined by rough inclusions, the latter introduced and studied  within rough mereology, the fuzzified version of mereology. In this book basic classes of rough inclusions are defined and based on them methods for inducing granular structures from data are highlighted. The resulting granular structures are subjected to classifying algorithms, notably k—nearest  neighbors and bayesian classifiers. Experimental results are given in detail both in tabular and visualized form for fourteen data sets from UCI data repository. A striking feature of granular classifiers obtained by this approach is that preserving the accuracy of them on original data, they reduce  substantially the size of the granulated data set as well as the set of granular...

  5. Disinfection of bacteria attached to granular activated carbon.

    Science.gov (United States)

    LeChevallier, M W; Hassenauer, T S; Camper, A K; McFeters, G A

    1984-01-01

    Heterotrophic plate count bacteria, coliform organisms, and pathogenic microorganisms attached to granular activated carbon particles were examined for their susceptibility to chlorine disinfection. When these bacteria were grown on carbon particles and then disinfected with 2.0 mg of chlorine per liter (1.4 to 1.6 mg of free chlorine residual per liter after 1 h) for 1 h, no significant decrease in viable counts was observed. Washed cells attached to the surface of granular activated carbon particles showed similar resistance to chlorine, but a progressive increase in sublethal injury was found. Observations made by scanning electron microscope indicated that granular activated carbon was colonized by bacteria which grow in cracks and crevices and are coated by an extracellular slime layer. These data suggest a possible mechanism by which treatment and disinfection barriers can be penetrated and pathogenic bacteria may enter drinking water supplies. Images PMID:6508306

  6. PENGEMBANGAN MEDIA BERBASIS MULTIMEDIA INTERAKTIF UNTUK MENINGKATKAN PEMAHAMAN SISWA MAN 2 BATU MATERI KINGDOM ANIMALIA

    Directory of Open Access Journals (Sweden)

    Feni Nur’ain

    2015-03-01

    Full Text Available Learning biology plays an important role in the educational process as well as the development of technology, because biology has an effort for human to generate interest in science and technology development.Various issues that arise in school in biology learning materials associated with the Kingdom Animalia and the material is very much difficult for students to understand and time limitations in the learning process. So there should be used development of teaching media to overcome this. The purpose of this study are: (1 to know the effectiveness of the implementation of teaching media development, (2 to know the level of students understanding by using the application of teaching media development. This type of research is development research or Research and Development (R & D. the development used is based on the development steps from Borg & Gall (1983 modified from Sukmadinata (2010 which includes three steps, namely: preliminary study, development and validation. To determine the effectiveness of the implementation of teaching media development is done by giving the questionnaire to students. To determine the level of students understanding performed pretest and posttest. The research was conducted on 28 March to 29 September 2013 at MAN 2 Batu Malang. The results of this development in the form of teaching media product Biology that has been through some trials and revisions of the experts and students. Based on the feasibility of media experts, subject matter experts, and students teaching media are stated that it is very viable and effective used in learning. Based on the experimental test on class treatment there was an increasing students' understanding of the material of the Kingdom Animalia that is the average value before using the media (pretest increased from 41.60 to 90.3 after using the media (posttest, while the control class average value before reading textbooks (pretest increased from 48.80 to 68.60 (posttest after

  7. Granular contact dynamics using mathematical programming methods

    DEFF Research Database (Denmark)

    Krabbenhoft, K.; Lyamin, A. V.; Huang, J.

    2012-01-01

    granular contact dynamics formulation uses an implicit time discretization, thus allowing for large time steps. Moreover, in the limit of an infinite time step, the general dynamic formulation reduces to a static formulation that is useful in simulating common quasi-static problems such as triaxial tests...... is developed and it is concluded that the associated sliding rule, in the context of granular contact dynamics, may be viewed as an artifact of the time discretization and that the use of an associated flow rule at the particle scale level generally is physically acceptable. (C) 2012 Elsevier Ltd. All rights...

  8. International Workshop on Traffic and Granular Flow

    CERN Document Server

    Herrmann, Hans; Schreckenberg, Michael; Wolf, Dietrich; Social, Traffic and Granular Dynamics

    2000-01-01

    "Are there common phenomena and laws in the dynamic behavior of granular materials, traffic, and socio-economic systems?" The answers given at the international workshop "Traffic and Granular Flow '99" are presented in this volume. From a physical standpoint, all these systems can be treated as (self)-driven many-particle systems with strong fluctuations, showing multistability, phase transitions, non-linear waves, etc. The great interest in these systems is due to several unexpected new discoveries and their practical relevance for solving some fundamental problems of today's societies. This includes intelligent measures for traffic flow optimization and methods from "econophysics" for stabilizing (stock) markets.

  9. Granular cells Tumor in the gastrointestinal tract

    International Nuclear Information System (INIS)

    Castano LL, Rodrigo; Gaitan B, Maria H; Juliao E, Fabian

    2005-01-01

    Granular cells tumors are ubiquitous lesions in the gastrointestinal tract, are rare and asymptomatic and they are generally an incidental discovery at gastroduodenoscopy or colonoscopy. In the gastrointestinal tract they are more frequently located in the esophagus, right colon and rectum, stomach, appendix, small intestine or biliopancreatic tract. This article describes three patients with four tumors of granular cells in rectum, esophagus (2 lesions) and appendix. It becomes special emphasis in their neural origin, their benign behavior that justifies the endoscopic resections or limited surgical excisions and the necessity of a pursuit for the possibility, although little, of malignant transformation

  10. Rheological Behavior of Dense Assemblies of Granular Materials

    International Nuclear Information System (INIS)

    Sundaresan, Sankaran; Tardos, Gabriel I.; Subramaniam, Shankar

    2011-01-01

    Assemblies of granular materials behave differently when they are owing rapidly, from when they are slowly deforming. The behavior of rapidly owing granular materials, where the particle-particle interactions occur largely through binary collisions, is commonly related to the properties of the constituent particles through the kinetic theory of granular materials. The same cannot be said for slowly moving or static assemblies of granular materials, where enduring contacts between particles are prevalent. For instance, a continuum description of the yield characteristics of dense assemblies of particles in the quasistatic ow regime cannot be written explicitly on the basis of particle properties, even for cohesionless particles. Continuum models for this regime have been proposed and applied, but these models typically assume that the assembly is at incipient yield and they are expressed in terms of the yield function, which we do not yet know how to express in terms of particle-level properties. The description of the continuum rheology in the intermediate regime is even less understood. Yet, many practically important flows in nature and in a wide range of technological applications occur in the dense flow regime and at the transition between dilute and dense regimes; the lack of validated continuum rheological models for particle assemblies in these regimes limits predictive modeling of such flows. This research project is aimed at developing such rheological models.

  11. Advanced Granular System Modeling, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Spaceports of the future will utilize new granular materials in unique applications including insulation for cryogenic tanks and Lunar regolith processing for usable...

  12. Erosion of a wet/dry granular interface

    Science.gov (United States)

    Jop, Pierre; Lefebvre, Gautier

    2013-04-01

    To model the dynamic of landslides, the evolution of the interface between the erodible ground and the flowing material is still studied experimentally or numerically (ie. Mangeney et al. 2010, Iverson 2012). In some cases, the basal material is more cohesive than the flowing one. Such situation arises for example due to cementation or humidity. What are the exchange rates between these phases? What is the coupling between the evolution of the interface and the flow? We studied the erosion phenomenon and performed laboratory experiments to focus on the interaction between a cohesive unsaturated granular material and a dry granular flow. Both materials were spherical grains, the cohesion being induced by adding a given mass of liquid to the grains. Two configurations were explored: a circular aggregate submitted to a dry flow in a rotating drum, and a granular flow eroding a wet granular pile. First, we focused on the influence of the cohesion, controlled by the liquid properties, such as the surface tension and the viscosity. Then the flow characteristics were modified by varying the grain size and density. These results allowed us to present a model for the erosion mechanisms, based on the flow and fluid properties. The main results are the need to take into account the whole probability distribution the stress applied on the wet grains and that both the surface tension and the viscosity are important since they play a different roles. The latter is mainly responsible of the time scale of the dynamic of a wet grain, while the former acts as a threshold on the force distribution. In the second configuration, we could also control the inclination of the slope. This system supported the previous model and moreover revealed an interface instability, leading the formation of steep steps, which is a reminiscence of the cyclic-steps observed during river-channel incision (Parker and Izumi 2000). We will present the dynamics of such granular steps. [1] Mangeney, A., O

  13. Intermediate layer thickness dependence on switching field distribution in perpendicular recording media

    International Nuclear Information System (INIS)

    Sbiaa, R.; Gandhi, R.; Srinivasan, K.; Piramanayagam, S.N.; Seoh, R.M.

    2009-01-01

    The effect of intermediate layer (IL) thickness on crystallographic texture and magnetic properties of CoCrPtSiO 2 granular perpendicular recording media was investigated with switching field distribution (SFD) as the focus. Even though the c-axis orientation of the Co-based recording layer (RL) broadens with the reduction of IL thickness, the SFD becomes narrower. This result demonstrates that the intrinsic SFD is not directly dependent on c-axis orientation of the recording layer but instead dependent on the magnitude of exchange coupling. It is thus possible to have a medium with thin IL and narrow SFD. This is desirable for bit-patterned media (BPM), where highly exchange-coupled grains are required.

  14. Boundary effects in a quasi-two-dimensional driven granular fluid.

    Science.gov (United States)

    Smith, N D; Smith, M I

    2017-12-01

    The effect of a confining boundary on the spatial variations in granular temperature of a driven quasi-two-dimensional layer of particles is investigated experimentally. The radial drop in the relative granular temperature ΔT/T exhibits a maximum at intermediate particle numbers which coincides with a crossover from kinetic to collisional transport of energy. It is also found that at low particle numbers, the distributions of radial velocities are increasingly asymmetric as one approaches the boundary. The radial and tangential granular temperatures split, and in the tails of the radial velocity distribution there is a higher population of fast moving particles traveling away rather than towards the boundary.

  15. On creating macroscopically identical granular systems with different numbers of particles

    Science.gov (United States)

    van der Meer, Devaraj; Rivas, Nicolas

    2015-11-01

    One of the fundamental differences between granular and molecular hydrodynamics is the enormous difference in the total number of constituents. The small number of particles implies that the role of fluctuations in granular dynamics is of paramount importance. To obtain more insight in these fluctuations, we investigate to what extent it is possible to create identical granular hydrodynamic states with different number of particles. A definition is given of macroscopically equivalent systems, and the dependency of the conservation equations on the particle size is studied. We show that, in certain cases, and by appropriately scaling the microscopic variables, we are able to compare systems with significantly different number of particles that present the same macroscopic phenomenology. We apply these scalings in simulations of a vertically vibrated system, namely the density inverted granular Leidenfrost state and its transition to a buoyancy-driven convective state.

  16. Effect of Wetting and Contamination of Granular Beds During Sphere Impact

    KAUST Repository

    Kouraytem, Nadia

    2013-03-01

    This thesis presents results from an experimental study of the impact of dense solid spheres onto granular beds. The overall aim is to further our understanding of the dynamical response of granular materials to impact. In order to do this, we will study both the initial penetration stages and peak acceleration exerted on the sphere by using high-speed imaging. Another critical part is to measure the penetration depth of the sphere and calculate the corresponding depth-averaged stopping force. Both of these main focal points will be assessed for not only dry, but wet and “contaminated” grains, whereby the granular bed will be comprised of two distinct size ranges of base grains. In doing so, we aim to broadly determine whether contaminated grains or wet grains are more effective at increasing the tensile strength of granular materials.

  17. Developing android-based science instructional media to improve scientific literacy of junior high school students

    Science.gov (United States)

    Farida, I. I.; Jumadi; Wilujeng; Senam

    2018-04-01

    The aims of this study are: to develop android-based science instructional media and to reveal the characteristic, the quality, and the effectiveness of android-based science instructional media with global warming topic to increase junior high school students’ scientific literacy. This study is a development research. The instructional media were reviewed by a media expert, a material expert, science teachers, peer reviewers, and students. The data was collected using media evaluation questionnaires. The results of the study showed that: (1) the android-based science instructional media has characteristics including interesting visualization, easy to use, flexible, and practical, (2) the android-based science instructional media was appropriate for teaching, in terms of material evaluation aspects, media evaluation aspects, and based on student test results, and (3) the android-based science instructional media can effectively used for teaching.

  18. Experimental and analytical investigations of granular materials: Shear flow and convective heat transfer

    Science.gov (United States)

    Ahn, Hojin

    1989-12-01

    Granular materials flowing down an inclined chute were studied experimentally and analytically. Characteristics of convective heat transfer to granular flows were also investigated experimentally and numerically. Experiments on continuous, steady flows of granular materials in an inclined chute were conducted with the objectives of understanding the characteristics of chute flows and of acquiring information on the rheological behavior of granular material flow. Existing constitutive equations and governing equations were used to solve for fully developed chute flows of granular materials, and thus the boundary value problem was formulated with two parameters (the coefficient of restitution between particles, and the chute inclination) and three boundary values at the chute base wall (the values of solid fraction, granular temperature, and mean velocity at the wall). The boundary value problem was numerically solved by the shooting method. These analytical results were also compared with the present experimental values and with the computer simulations by other investigators in their literature. Experiments on heat transfer to granular flows over a flat heating plate were conducted with three sizes of glass beads, polystyrene beads, and mustard seeds. A modification on the existing model for the convective heat transfer was made using the effective Nusselt number and the effective Peclet number, which include the effects of solid fraction variations. The slightly modified model could describe the heat transfer characteristics of both fast and slow flows (supercritical and subcritical). A numerical analysis of the transfer to granular flows was also performed. The results were compared with the present experimental data, and reasonable agreement was found in the comparison.

  19. An automata model of granular materials

    International Nuclear Information System (INIS)

    Gutt, G.M.; Haff, P.K.

    1990-01-01

    In this paper a new modeling technique (the Lattice Grain Model) is presented for the simulation of two-dimensional granular systems involving large numbers of grains. These granular systems may include both high shear rate regions as well as static plugs of grains and cannot easily be handled within the framework of existing continuum theories such as soil mechanics. The Lattice Grain Model (LGrM) is similar to the Lattice Gas Model (LBM). This allows large simulations to be programmed onto a hypercube concurrent processor in a straightforward manner. However, it differs from LBM in that it includes the inelastic collisions and volume-filling properties of macroscopic grains. Examples to be presented will include Couette flow, flow through an hourglass, and gravity-driven flows around obstacles

  20. Slow creep in soft granular packings.

    Science.gov (United States)

    Srivastava, Ishan; Fisher, Timothy S

    2017-05-14

    Transient creep mechanisms in soft granular packings are studied numerically using a constant pressure and constant stress simulation method. Rapid compression followed by slow dilation is predicted on the basis of a logarithmic creep phenomenon. Characteristic scales of creep strain and time exhibit a power-law dependence on jamming pressure, and they diverge at the jamming point. Microscopic analysis indicates the existence of a correlation between rheology and nonaffine fluctuations. Localized regions of large strain appear during creep and grow in magnitude and size at short times. At long times, the spatial structure of highly correlated local deformation becomes time-invariant. Finally, a microscale connection between local rheology and local fluctuations is demonstrated in the form of a linear scaling between granular fluidity and nonaffine velocity.

  1. Kinetic Theory of Granular Gases

    International Nuclear Information System (INIS)

    Trizac, Emmanuel

    2005-01-01

    coefficients, that are again velocity dependent. Th is seems to be the price of a consistent approach, which does not lend itself to much insight. In addition, the behaviour of driven systems is not addressed, whereas in the realm of granular media, force-free systems are the exception rather than the rule. The differences between constant ε and visco-elastic models is presumably less pronounced in the driven case. Study of driven systems also reveals that the rheology of granular gases is intrinsically non-Newtonian, which is a key feature. Finally, the powerful direct simulation Monte Carlo technique is not described, whereas it is an important tool, particularly relevant for the physics of the Boltzmann equation, and straightforward to implement in its simplest version. N Brilliantov and T Poeschel concentrate on the (equally relevant) molecular dynamics method instead. In conclusion, the book fills a gap in the field. The companion webpage from where molecular dynamics and symbolic algebra programs can be downloaded is also useful. (book review)

  2. Kinetic Theory of Granular Gases

    Energy Technology Data Exchange (ETDEWEB)

    Trizac, Emmanuel [Center of Theoretical Biological Physics, UC San Diego, La Jolla, CA 92093-0374 (United States); Laboratoire de Physique Theorique et Modeles Statistiques, Campus Universitaire, 91405 Orsay (France)

    2005-11-25

    tangential and normal restitution coefficients, that are again velocity dependent. Th is seems to be the price of a consistent approach, which does not lend itself to much insight. In addition, the behaviour of driven systems is not addressed, whereas in the realm of granular media, force-free systems are the exception rather than the rule. The differences between constant {epsilon} and visco-elastic models is presumably less pronounced in the driven case. Study of driven systems also reveals that the rheology of granular gases is intrinsically non-Newtonian, which is a key feature. Finally, the powerful direct simulation Monte Carlo technique is not described, whereas it is an important tool, particularly relevant for the physics of the Boltzmann equation, and straightforward to implement in its simplest version. N Brilliantov and T Poeschel concentrate on the (equally relevant) molecular dynamics method instead. In conclusion, the book fills a gap in the field. The companion webpage from where molecular dynamics and symbolic algebra programs can be downloaded is also useful. (book review)

  3. Culture and Language Teaching through Media

    Science.gov (United States)

    Tanriverdi, Belgin; Apak, Ozlem

    2008-01-01

    The topic of teaching and learning culture has been a matter of considerable interest to language educators and much has been written about the role of culture in foreign language instruction over the past two decades. ESL students whose success in a new environment is conditioned not only by their mastery of the new language, but also, and…

  4. Effect of Wetting and Contamination of Granular Beds During Sphere Impact

    KAUST Repository

    Kouraytem, Nadia

    2013-01-01

    This thesis presents results from an experimental study of the impact of dense solid spheres onto granular beds. The overall aim is to further our understanding of the dynamical response of granular materials to impact. In order to do this, we

  5. Web-based Media at European Universities: Systems, Usage, and Motivation

    DEFF Research Database (Denmark)

    Godsk, Mikkel

    2009-01-01

    This paper presents the results of two surveys analyzing the usage of and the systems available for web-based media at European universities, and how the teachers can be motivated to increase their usage of such materials in their teaching practice. The surveys were carried out April-May 2009 among...... obvious. The surveys also show that many teachers are already using web-based media in their teaching practice and by addressing some of their teaching circumstances it would be possible to increase the usage even further. Based on these results the paper presents five initiatives to motivate the teachers...

  6. A Queer Critical Media Literacies Framework in a Digital Age

    Science.gov (United States)

    Leent, Lisa; Mills, Kathy

    2018-01-01

    Media literacy skills are focal for many educators across the globe in an age of ubiquitous access to the Internet and the rapid circulation of digital texts. A critical media literacies perspective is often a key element in teaching adolescents to read a range of texts. A queer critical media literacies pedagogy supports a social justice agenda…

  7. Biotin- and Glycoprotein-Coated Microspheres as Surrogates for Studying Filtration Removal of Cryptosporidium parvum in a Granular Limestone Aquifer Medium.

    Science.gov (United States)

    Stevenson, M E; Blaschke, A P; Toze, S; Sidhu, J P S; Ahmed, W; van Driezum, I H; Sommer, R; Kirschner, A K T; Cervero-Aragó, S; Farnleitner, A H; Pang, L

    2015-07-01

    Members of the genus Cryptosporidium are waterborne protozoa of great health concern. Many studies have attempted to find appropriate surrogates for assessing Cryptosporidium filtration removal in porous media. In this study, we evaluated the filtration of Cryptosporidium parvum in granular limestone medium by the use of biotin- and glycoprotein-coated carboxylated polystyrene microspheres (CPMs) as surrogates. Column experiments were carried out with core material taken from a managed aquifer recharge site in Adelaide, Australia. For the experiments with injection of a single type of particle, we observed the total removal of the oocysts and glycoprotein-coated CPMs, a 4.6- to 6.3-log10 reduction of biotin-coated CPMs, and a 2.6-log10 reduction of unmodified CPMs. When two different types of particles were simultaneously injected, glycoprotein-coated CPMs showed a 5.3-log10 reduction, while the uncoated CPMs displayed a 3.7-log10 reduction, probably due to particle-particle interactions. Our results confirm that glycoprotein-coated CPMs are the most accurate surrogates for C. parvum; biotin-coated CPMs are slightly more conservative, while unmodified CPMs are markedly overly conservative for predicting C. parvum removal in granular limestone medium. The total removal of C. parvum observed in our study suggests that granular limestone medium is very effective for the filtration removal of C. parvum and could potentially be used for the pretreatment of drinking water and aquifer storage recovery of recycled water. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  8. Density profiles of granular gases studied by molecular dynamics and Brownian bridges

    Science.gov (United States)

    Peñuñuri, F.; Montoya, J. A.; Carvente, O.

    2018-02-01

    Despite the inherent frictional forces and dissipative collisions, confined granular matter can be regarded as a system in a stationary state if we inject energy continuously. Under these conditions, both the density and the granular temperature are, in general, non-monotonic variables along the height of the container. In consequence, an analytical description of a granular system is hard to conceive. Here, by using molecular dynamics simulations, we measure the packing fraction profiles for a vertically vibrating three-dimensional granular system in several gaseous-like stationary states. We show that by using the Brownian bridge concept, the determined packing fraction profiles can be reproduced accurately and give a complete description of the distribution of the particles inside the simulation box.

  9. Rough – Granular Computing knowledge discovery models

    Directory of Open Access Journals (Sweden)

    Mohammed M. Eissa

    2016-11-01

    Full Text Available Medical domain has become one of the most important areas of research in order to richness huge amounts of medical information about the symptoms of diseases and how to distinguish between them to diagnose it correctly. Knowledge discovery models play vital role in refinement and mining of medical indicators to help medical experts to settle treatment decisions. This paper introduces four hybrid Rough – Granular Computing knowledge discovery models based on Rough Sets Theory, Artificial Neural Networks, Genetic Algorithm and Rough Mereology Theory. A comparative analysis of various knowledge discovery models that use different knowledge discovery techniques for data pre-processing, reduction, and data mining supports medical experts to extract the main medical indicators, to reduce the misdiagnosis rates and to improve decision-making for medical diagnosis and treatment. The proposed models utilized two medical datasets: Coronary Heart Disease dataset and Hepatitis C Virus dataset. The main purpose of this paper was to explore and evaluate the proposed models based on Granular Computing methodology for knowledge extraction according to different evaluation criteria for classification of medical datasets. Another purpose is to make enhancement in the frame of KDD processes for supervised learning using Granular Computing methodology.

  10. The challenge of social media

    DEFF Research Database (Denmark)

    Tække, Jesper; Paulsen, Michael Eric

    must find new ways of doing things, because our media milieu has changed. Also in schools many things are changing; the classroom is no longer a closed room where interaction is isolated from the external world. Thousands of parallel interaction systems are intermingling within the social situations...... in the classrooms. On this basis, we present the action research project Socio Media Education, which tries to develop new ways of teaching that feed to the new media environment. The aim of the paper is, on an early stage, to report about the challenge of the new social media and how the project tries to find......Like with the emergence of oral language and the invention of writing, printing, and electronic media, today digital media entail a revolution of society. In our present time we are living through the incunabula of a digital revolution. This means that many things in society find new forms, and we...

  11. Teaching Machines and Programmed Instruction; an Introduction.

    Science.gov (United States)

    Fry, Edward B.

    Teaching machines and programed instruction represent new methods in education, but they are based on teaching principles established before the development of media technology. Today programed learning materials based on the new technology enjoy increasing popularity for several reasons: they apply sound psychological theories; the materials can…

  12. Flowability of granular materials with industrial applications - An experimental approach

    Science.gov (United States)

    Torres-Serra, Joel; Romero, Enrique; Rodríguez-Ferran, Antonio; Caba, Joan; Arderiu, Xavier; Padullés, Josep-Manel; González, Juanjo

    2017-06-01

    Designing bulk material handling equipment requires a thorough understanding of the mechanical behaviour of powders and grains. Experimental characterization of granular materials is introduced focusing on flowability. A new prototype is presented which performs granular column collapse tests. The device consists of a channel whose design accounts for test inspection using visualization techniques and load measurements. A reservoir is attached where packing state of the granular material can be adjusted before run-off to simulate actual handling conditions by fluidisation and deaeration of the pile. Bulk materials on the market, with a wide range of particle sizes, can be tested with the prototype and the results used for classification in terms of flowability to improve industrial equipment selection processes.

  13. Characterization, Modeling and Application of Aerobic Granular Sludge for Wastewater Treatment

    Science.gov (United States)

    Liu, Xian-Wei; Yu, Han-Qing; Ni, Bing-Jie; Sheng, Guo-Ping

    Recently extensive studies have been carried out to cultivate aerobic granular sludge worldwide, including in China. Aerobic granules, compared with conventional activated sludge flocs, are well known for their regular, dense, and strong microbial structure, good settling ability, high biomass retention, and great ability to withstand shock loadings. Studies have shown that the aerobic granules could be applied for the treatment of low- or high-strength wastewaters, simultaneous removal of organic carbon, nitrogen and phosphorus, and decomposition of toxic wastewaters. Thus, this new form of activate sludge, like anaerobic granular sludge, could be employed for the treatment of municipal and industrial wastewaters in near future. This chapter attempts to provide an up-to-date review on the definition, cultivation, characterization, modeling and application of aerobic granular sludge for biological wastewater treatment. This review outlines some important discoveries with regard to the factors affecting the formation of aerobic granular sludge, their physicochemical characteristics, as well as their microbial structure and diversity. It also summarizes the modeling of aerobic granule formation. Finally, this chapter highlights the applications of aerobic granulation technology in the biological wastewater treatment. It is concluded that the knowledge regarding aerobic granular sludge is far from complete. Although previous studies in this field have undoubtedly improved our understanding on aerobic granular sludge, it is clear that much remains to be learned about the process and that many unanswered questions still remain. One of the challenges appears to be the integration of the existing and growing scientific knowledge base with the observations and applications in practice, which this paper hopes to partially achieve.

  14. Superconductivity effects near metal-insulator transition in granular idnium films

    International Nuclear Information System (INIS)

    Belevtsev, B.I.; Komnik, Yu.F.; Fomin, A.V.

    1986-01-01

    The influence of granules superconductivity on the electric properties of granular indium films is investigated under the conditions of partial or full granular localization of electrons. At temperatures below 5 K a minimum of electric resistance and negative magnetoresistance are revealed which are attributed to the competition of hopping conductivity and Josephson intergranular tunneling of electrons

  15. Martian gullies: possible formation mechanism by dry granular material..

    Science.gov (United States)

    Cedillo-Flores, Y.; Durand-Manterola, H. J.

    section Some of the geomorphological features in Mars are the gullies Some theories developed tried explain its origin either by liquid water liquid carbon dioxide or flows of dry granular material We made a comparative analysis of the Martian gullies with the terrestrial ones We propose that the mechanism of formation of the gullies is as follows In winter CO 2 snow mixed with sand falls in the terrain In spring the CO 2 snow sublimate and gaseous CO 2 make fluid the sand which flows like liquid eroding the terrain and forming the gullies By experimental work with dry granular material we simulated the development of the Martian gullies injecting air in the granular material section We present the characteristics of some terrestrial gullies forms at cold environment sited at Nevado de Toluca Volcano near Toluca City M e xico We compare them with Martian gullies choose from four different areas to target goal recognize or to distinguish to identify possible processes evolved in its formation Also we measured the lengths of those Martian gullies and the range was from 24 m to 1775 meters Finally we present results of our experimental work at laboratory with dry granular material

  16. Traffic and Granular Flow’05

    CERN Document Server

    Pöschel, Thorsten; Kühne, Reinhart; Schreckenberg, Michael; Wolf, Dietrich

    2007-01-01

    The conference series Tra?c and Granular Flow has been established in 1995 and has since then been held biannually. At that time, the investigation of granular materials and tra?c was still somewhat exotic and was just starting to become popular among physicists. Originally the idea behind this conference series was to facilitate the c- vergence of the two ?elds, inspired by the similarities of certain phenomena and the use of similar theoretical methods. However, in recent years it has become clear that probably the di?erences between the two systems are much more interesting than the similarities. Nevertheless, the importance of various interrelations among these ?elds is still growing. The workshop continues to o?er an opportunity to stimulate this interdisciplinary research. Over the years the spectrum of topics has become much broader and has included also problems related to topics ranging from social dynamics to - ology. The conference manages to bring together people with rather di?erent background, r...

  17. Magnetoresistances in Ni80Fe20-ITO granular film

    International Nuclear Information System (INIS)

    Gao Chunhong; Chen Ke; Yang Yanxia; Xiong Yuanqiang; Chen Peng

    2012-01-01

    Highlights: ► Magnetoresistance (MR) in Ni 80 Fe 20 -ITO granular film are investigated. ► MR is positive at high temperature, and is negative at low temperature. ► MR results from the competition among three mechanisms. - Abstract: The magnetic properties, electrical properties and magnetoresistance are investigated in Ni 80 Fe 20 -ITO granular film with various volume fractions V NF of Ni 80 Fe 20 . The room temperature magnetization hysteresis of sample with V NF = 25% shows superparamagnetic behavior. Current-voltage curve of sample with V NF = 25% at 175 K shows typical tunneling-type behavior. The magnetoresistances of samples with low V NF are positive at high temperature, and are negative at low temperature. The temperature-dependent magnetoresistances result from the competition among ordinary magnetoresistances, the granular-typed tunneling magnetoresistance and the spin-mixing induced magnetoresistances.

  18. Granular nanocrystalline zirconia electrolyte layers deposited on porous SOFC cathode substrates

    International Nuclear Information System (INIS)

    Seydel, Johannes; Becker, Michael; Ivers-Tiffee, Ellen; Hahn, Horst

    2009-01-01

    Thin granular yttria-stabilized zirconia (YSZ) electrolyte layers were prepared by chemical vapor synthesis and deposition (CVD/CVS) on a porous substoichiometric lanthanum-strontium-manganite (ULSM) solid oxide fuel cell cathode substrate. The substrate porosity was optimized with a screen printed fine porous buffer layer. Structural analysis by scanning electron microscopy showed a homogeneous, granular nanocrystalline layer with a microstructure that was controlled via reactor settings. The CVD/CVS gas-phase process enabled the deposition of crack-free granular YSZ films on porous ULSM substrates. The electrolyte layers characterized with impedance spectroscopy exhibited enhanced grain boundary conductivity.

  19. Use of Audiovisual Media and Equipment by Medical Educationists ...

    African Journals Online (AJOL)

    The most frequently used audiovisual medium and equipment is transparency on Overhead projector (O. H. P.) while the medium and equipment that is barely used for teaching is computer graphics on multi-media projector. This study also suggests ways of improving teaching-learning processes in medical education, ...

  20. Multi-granularity synthesis segmentation for high spatial resolution Remote sensing images

    International Nuclear Information System (INIS)

    Yi, Lina; Liu, Pengfei; Qiao, Xiaojun; Zhang, Xiaoning; Gao, Yuan; Feng, Boyan

    2014-01-01

    Traditional segmentation method can only partition an image in a single granularity space, with segmentation accuracy limited to the single granularity space. This paper proposes a multi-granularity synthesis segmentation method for high spatial resolution remote sensing images based on a quotient space model. Firstly, we divide the whole image area into multiple granules (regions), each region is consisted of ground objects that have similar optimal segmentation scale, and then select and synthesize the sub-optimal segmentations of each region to get the final segmentation result. To validate this method, the land cover category map is used to guide the scale synthesis of multi-scale image segmentations for Quickbird image land use classification. Firstly, the image is coarsely divided into multiple regions, each region belongs to a certain land cover category. Then multi-scale segmentation results are generated by the Mumford-Shah function based region merging method. For each land cover category, the optimal segmentation scale is selected by the supervised segmentation accuracy assessment method. Finally, the optimal scales of segmentation results are synthesized under the guide of land cover category. Experiments show that the multi-granularity synthesis segmentation can produce more accurate segmentation than that of a single granularity space and benefit the classification

  1. Measurements of granular flow dynamics with high speed digital images

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jingeol [Univ. of Florida, Gainesville, FL (United States)

    1994-01-01

    The flow of granular materials is common to many industrial processes. This dissertation suggests and validates image processing algorithms applied to high speed digital images to measure the dynamics (velocity, temperature and volume fraction) of dry granular solids flowing down an inclined chute under the action of gravity. Glass and acrylic particles have been used as granular solids in the experiment. One technique utilizes block matching for spatially averaged velocity measurements of the glass particles. This technique is compared with the velocity measurement using an optic probe which is a conventional granular flow velocity measurement device. The other technique for measuring the velocities of individual acrylic particles is developed with correspondence using a Hopfield network. This technique first locates the positions of particles with pattern recognition techniques, followed by a clustering technique, which produces point patterns. Also, several techniques are compared for particle recognition: synthetic discriminant function (SDF), minimum average correlation energy (MACE) filter, modified minimum average correlation energy (MMACE) filter and variance normalized correlation. The author proposes an MMACE filter which improves generalization of the MACE filter by adjusting the amount of averaged spectrum of training images in the spectrum whitening stages of the MACE filter. Variance normalized correlation is applied to measure the velocity and temperature of flowing glass particles down the inclined chute. The measurements are taken for the steady and wavy flow and qualitatively compared with a theoretical model of granular flow.

  2. Mathematics and Mechanics of Granular Materials

    CERN Document Server

    Hill, James M

    2005-01-01

    Granular or particulate materials arise in almost every aspect of our lives, including many familiar materials such as tea, coffee, sugar, sand, cement and powders. At some stage almost every industrial process involves a particulate material, and it is usually the cause of the disruption to the smooth running of the process. In the natural environment, understanding the behaviour of particulate materials is vital in many geophysical processes such as earthquakes, landslides and avalanches. This book is a collection of current research from some of the major contributors in the topic of modelling the behaviour of granular materials. Papers from every area of current activity are included, such as theoretical, numerical, engineering and computational approaches. This book illustrates the numerous diverse approaches to one of the outstanding problems of modern continuum mechanics.

  3. Self-assembly and speed distributions of active granular particles

    Science.gov (United States)

    Sánchez, R.; Díaz-Leyva, P.

    2018-06-01

    The relationship between the dynamics of self-propelled systems and the self-assembly of structured clusters are studied via the experimental speed distributions of submonolayers of self-propelled granular particles. A distribution developed for non-self-propelled granular particles describes the speed distributions remarkably well, despite some of the assumptions behind its original derivation not being applicable. This is explained in terms of clustering and dissipation being the key phenomena governing this regime.

  4. Ceramic media amended with metal oxide for the capture of viruses in drinking water.

    Science.gov (United States)

    Brown, J; Sobsey, M D

    2009-04-01

    Ceramic materials that can adsorb and/or inactivate viruses in water may find widespread application in low-tech drinking-water treatment technologies in developing countries, where porous ceramic filters and ceramic granular media filters are increasingly promoted for that purpose. We examined the adsorption and subsequent inactivation of bacteriophages MS2 and (phiX-174 on five ceramic media in batch adsorption studies to determine media suitability for use in a ceramic water filter application. The media examined were a kaolinitic ceramic medium and four kaolinitic ceramic media amended with iron or aluminium oxides that had been incorporated into the kaolinitic clays before firing. Batch adsorption tests indicate increased sorption and inactivation of surrogate viruses by media amended with Fe and Al oxide, with FeOOH-amended ceramic inactivating all bacteriophages up to 8 log10. Unmodified ceramic was a poor adsorbent of bacteriophages at less than 1 log10 adsorption-inactivation and high recovery of sorbed phages. These studies suggest that contact with ceramic media, modified with electropositive Fe or Al oxides, can reduce bacteriophages in waters to a greater extent than unmodified ceramic.

  5. Grain scale observations of stick-slip dynamics in fluid saturated granular fault gouge

    Science.gov (United States)

    Johnson, P. A.; Dorostkar, O.; Guyer, R. A.; Marone, C.; Carmeliet, J.

    2017-12-01

    We are studying granular mechanics during slip. In the present work, we conduct coupled computational fluid dynamics (CFD) and discrete element method (DEM) simulations to study grain scale characteristics of slip instabilities in fluid saturated granular fault gouge. The granular sample is confined with constant normal load (10 MPa), and sheared with constant velocity (0.6 mm/s). This loading configuration is chosen to promote stick-slip dynamics, based on a phase-space study. Fluid is introduced in the beginning of stick phase and characteristics of slip events i.e. macroscopic friction coefficient, kinetic energy and layer thickness are monitored. At the grain scale, we monitor particle coordination number, fluid-particle interaction forces as well as particle and fluid kinetic energy. Our observations show that presence of fluids in a drained granular fault gouge stabilizes the layer in the stick phase and increases the recurrence time. In saturated model, we observe that average particle coordination number reaches higher values compared to dry granular gouge. Upon slip, we observe that a larger portion of the granular sample is mobilized in saturated gouge compared to dry system. We also observe that regions with high particle kinetic energy are correlated with zones of high fluid motion. Our observations highlight that spatiotemporal profile of fluid dynamic pressure affects the characteristics of slip instabilities, increasing macroscopic friction coefficient drop, kinetic energy release and granular layer compaction. We show that numerical simulations help characterize the micromechanics of fault mechanics.

  6. Association of inclusion body myositis with T cell large granular lymphocytic leukaemia

    DEFF Research Database (Denmark)

    Greenberg, Steven A; Pinkus, Jack L; Amato, Anthony A

    2016-01-01

    SEE HOHLFELD AND SCHULZE-KOOPS DOI101093/BRAIN/AWW053 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE: Inclusion body myositis and T cell large granular lymphocytic leukaemia are rare diseases involving pathogenic cytotoxic CD8+ T cells. After encountering four patients with both disorders, we...... prospectively screened 38 patients with inclusion body myositis for the presence of expanded large granular lymphocyte populations by standard clinical laboratory methods (flow cytometry, examination of blood smears, and T cell receptor gene rearrangements), and performed muscle immunohistochemistry for CD8, CD......57, and TIA1. Most (22/38; 58%) patients with inclusion body myositis had aberrant populations of large granular lymphocytes in their blood meeting standard diagnostic criteria for T cell large granular lymphocytic leukaemia. These T cell populations were clonal in 20/20 patients and stably present...

  7. Media Education in Japan (Retrospect and Present Trends).

    Science.gov (United States)

    Takakuwa, Yasuo

    This overview of the development of media education in Japan begins with a discussion of the motion picture as entertainment and the public attitude toward film in Japan during the early years of the century. The introduction of film education into the schools in the 1920s--both teaching by film and teaching about film--is then described together…

  8. Granular chaos and mixing: Whirled in a grain of sand

    Energy Technology Data Exchange (ETDEWEB)

    Shinbrot, Troy, E-mail: shinbrot@rutgers.edu [Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey 08854 (United States)

    2015-09-15

    In this paper, we overview examples of chaos in granular flows. We begin by reviewing several remarkable behaviors that have intrigued researchers over the past few decades, and we then focus on three areas in which chaos plays an intrinsic role in granular behavior. First, we discuss pattern formation in vibrated beds, which we show is a direct result of chaotic scattering combined with dynamical dissipation. Next, we consider stick-slip motion, which involves chaotic scattering on the micro-scale, and which results in complex and as yet unexplained peculiarities on the macro-scale. Finally, we examine granular mixing, which we show combines micro-scale chaotic scattering and macro-scale stick-slip motion into behaviors that are well described by dynamical systems tools, such as iterative mappings.

  9. Granular chaos and mixing: Whirled in a grain of sand.

    Science.gov (United States)

    Shinbrot, Troy

    2015-09-01

    In this paper, we overview examples of chaos in granular flows. We begin by reviewing several remarkable behaviors that have intrigued researchers over the past few decades, and we then focus on three areas in which chaos plays an intrinsic role in granular behavior. First, we discuss pattern formation in vibrated beds, which we show is a direct result of chaotic scattering combined with dynamical dissipation. Next, we consider stick-slip motion, which involves chaotic scattering on the micro-scale, and which results in complex and as yet unexplained peculiarities on the macro-scale. Finally, we examine granular mixing, which we show combines micro-scale chaotic scattering and macro-scale stick-slip motion into behaviors that are well described by dynamical systems tools, such as iterative mappings.

  10. PEMANFAATAN MEDIA DALAM PEMBELAJARAN BIOLOGI DI SEKOLAH

    Directory of Open Access Journals (Sweden)

    Amna Emda

    2011-08-01

    Full Text Available In teaching learning process, teachers have to use some media of instruction. They have to be able to select appropriate media with the concept that they want to teach. In biology, especially the concept of biodiversity, the teacher should explain and introduce the students to various plants available around them including herb plants. It will be one of solution for a teacher to achieve an optimum goal if they can use the diverse plant around them. The successful of learning especially in the field of biology can be seen from cognitive, effective and psychomotoric aspects which is hoped to be achieved if the teachers as educators can guide their students to know about the plants in the field.

  11. Social Media Use Among Nurses: Literature Review.

    Science.gov (United States)

    Cordoş, Ariana Anamaria; Bolboacă, Sorana D

    2016-01-01

    The scope of the research was to increase the understanding of social media's influence among nurses while highlighting gaps in the literature and areas for further research. The search of PubMed database was performed in November 2015, using terms to identify peer-reviewed articles that describe the use of social media for nursing students or nurse practitioners. A systematic approach was used to retrieve papers and extract relevant data. There were identified 23 full text articles involving social media and nurse-related terminology. The majority of the studies were interventional (n = 20) that assessed social media as a teaching tool. Podcasts, Multiplayer virtual worlds and mixed social media platforms has also been assessed. Social media is used as a tool of information for nurses mainly as the means for engaging and communicating.

  12. An update on blast furnace granular coal injection

    Energy Technology Data Exchange (ETDEWEB)

    Hill, D.G. [Bethlehem Steel Corp., Burns Harbor, IN (United States); Strayer, T.J.; Bouman, R.W. [Bethlehem Steel Corp., PA (United States)

    1997-12-31

    A blast furnace coal injection system has been constructed and is being used on the furnace at the Burns Harbor Division of Bethlehem Steel. The injection system was designed to deliver both granular (coarse) and pulverized (fine) coal. Construction was completed on schedule in early 1995. Coal injection rates on the two Burns Harbor furnaces were increased throughout 1995 and was over 200 lbs/ton on C furnace in September. The injection rate on C furnace reached 270 lbs/ton by mid-1996. A comparison of high volatile and low volatile coals as injectants shows that low volatile coal replaces more coke and results in a better blast furnace operation. The replacement ratio with low volatile coal is 0.96 lbs coke per pound of coal. A major conclusion of the work to date is that granular coal injection performs very well in large blast furnaces. Future testing will include a processed sub-bituminous coal, a high ash coal and a direct comparison of granular versus pulverized coal injection.

  13. Using Realia to Teach Physically Disabled Students in Writing Descriptive Texts

    Directory of Open Access Journals (Sweden)

    Noorma Fitriana M. Zain

    2014-06-01

    Full Text Available This case study is focused on teaching descriptive texts by using realia. The writer took the 8th grade students of SMPLB Negeri Ungaran as the subjects of the study. The aim of this research is to know the implementation of teaching descriptive texts that cover parts, qualities, and characteristics of the objects. This study was carried out around four meetings. In each meeting, the researcher observed the situation of the class and the setudents’ activities in that classroom. The data collection method used in the research was observation, interview, and documentation. In implementating the research, the researcher found several problems and difficulties in teaching learning processes. One of them is that, the teaching physically disabled students are not easy. It has to be slowly because the students’ ability in writing the lesson is limited. The other problem comes from the teacher him/herself that never uses media or tools to teach physically disabled students. It is a matter of fact that teaching physically  disabled students needs media to make them easily understand the learning materials. One of the media that could be used is realia. From this research it is expected that the problems could be solved and a new paradigm in teaching descriptive texts for disabled students could be considered.

  14. Breakage mechanics for granular materials in surface-reactive environments

    Science.gov (United States)

    Zhang, Yida; Buscarnera, Giuseppe

    2018-03-01

    It is known that the crushing behaviour of granular materials is sensitive to the state of the fluids occupying the pore space. Here, a thermomechanical theory is developed to link such macroscopic observations with the physico-chemical processes operating at the microcracks of individual grains. The theory relies on the hypothesis that subcritical fracture propagation at intra-particle scale is the controlling mechanism for the rate-dependent, water-sensitive compression of granular specimens. First, the fracture of uniaxially compressed particles in surface-reactive environments is studied in light of irreversible thermodynamics. Such analysis recovers the Gibbs adsorption isotherm as a central component linking the reduction of the fracture toughness of a solid to the increase of vapour concentration. The same methodology is then extended to assemblies immersed in wet air, for which solid-fluid interfaces have been treated as a separate phase. It is shown that this choice brings the solid surface energy into the dissipation equations of the granular matrix, thus providing a pathway to (i) integrate the Gibbs isotherm with the continuum description of particle assemblies and (ii) reproduce the reduction of their yield strength in presence of high relative humidity. The rate-effects involved in the propagation of cracks and the evolution of breakage have been recovered by considering non-homogenous dissipation potentials associated with the creation of surface area at both scales. It is shown that the proposed model captures satisfactorily the compression response of different types of granular materials subjected to varying relative humidity. This result was achieved simply by using parameters based on the actual adsorption characteristics of the constituting minerals. The theory therefore provides a physically sound and thermodynamically consistent framework to study the behaviour of granular solids in surface-reactive environments.

  15. Granular flow down a flexible inclined plane

    Directory of Open Access Journals (Sweden)

    Sonar Prasad

    2017-01-01

    Full Text Available Discrete and continuous systems are commonly studied individually, but seldom together. Indeed, granular flows are typically studied through flows over a rigid base. Here, we investigate the behaviour of granular flows over an inclined, flexible base. The flexible base is modeled as a rigid platform mounted on springs and has one degree of freedom. The base vibrations are introduced by the flow. We simulate such flows through a discrete element method and compare with experiments. We find that a flexible base increased the upper limit of the inclination up to which a steady flow is possible by at least 3 degrees. This stabilized zone may have important implications in applications such as conveyor belts and chutes.

  16. Granularity as a Cognitive Factor in the Effectiveness of Business Process Model Reuse

    Science.gov (United States)

    Holschke, Oliver; Rake, Jannis; Levina, Olga

    Reusing design models is an attractive approach in business process modeling as modeling efficiency and quality of design outcomes may be significantly improved. However, reusing conceptual models is not a cost-free effort, but has to be carefully designed. While factors such as psychological anchoring and task-adequacy in reuse-based modeling tasks have been investigated, information granularity as a cognitive concept has not been at the center of empirical research yet. We hypothesize that business process granularity as a factor in design tasks under reuse has a significant impact on the effectiveness of resulting business process models. We test our hypothesis in a comparative study employing high and low granularities. The reusable processes provided were taken from widely accessible reference models for the telecommunication industry (enhanced Telecom Operations Map). First experimental results show that Recall in tasks involving coarser granularity is lower than in cases of finer granularity. These findings suggest that decision makers in business process management should be considerate with regard to the implementation of reuse mechanisms of different granularities. We realize that due to our small sample size results are not statistically significant, but this preliminary run shows that it is ready for running on a larger scale.

  17. Outside the Box Teaching Moments: Classroom-Tested Innovations

    Science.gov (United States)

    Whalen, D. Joel; Coker, Kesha K.

    2016-01-01

    The 2015 Society for Marketing Advances Teaching Moments sessions offered a wide variety of teaching interventions centered on gaining students' attention, increasing class participation, using lively student-engaging demonstrations, using props during lecture, using sales technology classroom applications, using social media, and many more.…

  18. Introduction

    Science.gov (United States)

    Starosvetsky, Yuli; Jayaprakash, K. R.; Hasan, Md. Arif; Vakakis, Alexander F.

    The study of mechanics of granular media dates back to the era of Coulomb. He was the first to postulate the yield condition for homogeneous solids and also conditions for failure in granular media [1-4]. In fact the ideal Coulomb material is the simplest granular material model wherein the shear stress along a plane is linearly proportional to the normal stress on that plane. This can be considered analogous to the Coulomb friction model in cohesion-free interfaces between solids. Initial research in this domain focused mainly on the statics of granular materials from a soil mechanics perspective. However, as the applications of granular materials broadened, the objectives of different research communities contradicted. For example, in geophysics or soil mechanics the objective is to regard granular media with properties of a solid in order to take considerable loads without yielding; on the other hand, in food grain or pharmaceutical industries the granular media is considered as fluids and their rheological properties are of interest. In fact granular media can exhibit both of these behaviors (and also the properties of a gas), and such unique features pave the way for their broad range applications...

  19. Physical modelling of granular flows at multiple-scales and stress levels

    Science.gov (United States)

    Take, Andy; Bowman, Elisabeth; Bryant, Sarah

    2015-04-01

    The rheology of dry granular flows is an area of significant focus within the granular physics, geoscience, and geotechnical engineering research communities. Studies performed to better understand granular flows in manufacturing, materials processing or bulk handling applications have typically focused on the behavior of steady, continuous flows. As a result, much of the research on relating the fundamental interaction of particles to the rheological or constitutive behaviour of granular flows has been performed under (usually) steady-state conditions and low stress levels. However, landslides, which are the primary focus of the geoscience and geotechnical engineering communities, are by nature unsteady flows defined by a finite source volume and at flow depths much larger than typically possible in laboratory experiments. The objective of this paper is to report initial findings of experimental studies currently being conducted using a new large-scale landslide flume (8 m long, 2 m wide slope inclined at 30° with a 35 m long horizontal base section) and at elevated particle self-weight in a 10 m diameter geotechnical centrifuge to investigate the granular flow behavior at multiple-scales and stress levels. The transparent sidewalls of the two flumes used in the experimental investigation permit the combination of observations of particle-scale interaction (using high-speed imaging through transparent vertical sidewalls at over 1000 frames per second) with observations of the distal reach of the landslide debris. These observations are used to investigate the applicability of rheological models developed for steady state flows (e.g. the dimensionless inertial number) in landslide applications and the robustness of depth-averaged approaches to modelling dry granular flow at multiple scales. These observations indicate that the dimensionless inertial number calculated for the flow may be of limited utility except perhaps to define a general state (e.g. liquid

  20. PALLADIUM-FACILITATED ELECTROLYTIC DECHLORINATION OF 2-CHLOROBIPHENYL USING A GRANULAR-GRAPHITE ELECTRODE.

    Science.gov (United States)

    Palladium-assisted electrocatalytic dechlorination of 2-chlorobiphenyl (2-Cl BP) in aqueous solutions was conducted in a membrane-separated electrochemical reactor with granular-graphite packed electrodes. The dechlorination took place at a granular-graphite cathode while Pd was ...

  1. Constitutive law of dense granular matter

    International Nuclear Information System (INIS)

    Hatano, Takahiro

    2010-01-01

    The frictional properties of dense granular matter under steady shear flow are investigated using numerical simulation. Shear flow tends to localize near the driving boundary unless the coefficient of restitution is close to zero and the driving velocity is small. The bulk friction coefficient is independent of shear rate in dense and slow flow, whereas it is an increasing function of shear rate in rapid flow. The coefficient of restitution affects the friction coefficient only in such rapid flow. Contrastingly, in dense and slow regime, the friction coefficient is independent of the coefficient of restitution and mainly determined by the elementary friction coefficient and the rotation of grains. It is found that the mismatch between the vorticity of flow and the angular frequency of grains plays a key role to the frictional properties of sheared granular matter.

  2. Granular cell tumor in an endangered Puerto Rican Amazon parrot (Amazon vittata)

    Science.gov (United States)

    Quist, C.F.; Latimer, K.S.; Goldade, S.L.; Rivera, A.; Dein, F.J.

    1999-01-01

    A 3 cm diameter mass from the metacarpus of a Puerto Rican Amazon parrot was diagnosed as a granular cell tumour based on light microscopy. The cytoplasmic granules were periodic-acid Schiff positive and diastase resistant. Ultrastructural characteristics of the cells included convoluted nuclei and the presence of numerous cytoplasmic tertiary lysosomes. This is only the second granular cell tumour reported in a bird. We speculate that most granular cell tumours are derived from cells that are engaged in some type of cellular degradative process, creating a similar morphologic appearance, but lacking a uniform histogenesis.

  3. Phosphorus removal from aquaculture effluents at the Northeast Fishery Center in Lamar, Pennsylvania using iron oxide sorption media

    Science.gov (United States)

    Sibrell, Philip; Kehler, Thomas

    2016-01-01

    Three different iron oxide-based sorption media samples were tested for removal of phosphorus (P) from fish hatchery effluents using fixed bed processing. Two of the media samples were derived from residuals produced by the treatment of acid mine drainage, which were then compared to granular ferric hydroxide (GFH), a commercially available sorption medium. All of the media types removed from 50 to 70% of the P from the incoming aquaculture wastewater over 70–175 days of operation without regeneration. In some of the sorption trials, the GFH media showed superior adsorption in the earlier stages of the trial, but the GFH appeared to reach saturation more quickly, so that media performance was similar – at about 60% removal of P – over a longer time period of 175 days. Media regeneration tests were also conducted for both the commercial and mine drainage media, and demonstrated longer term performance, with overall P removal of 50–55%, over 223 days of total operation, with the advantages of phosphorus recycle and media reuse.

  4. SKENARIO PEMBELAJARAN AKTIF, KREATIF, DAN MENYENANGKAN DALAM MENGEMBANGKAN KEMAMPUAN SISWA MENULIS KALIMAT MELALUI PEMANFAATAN MEDIA KARTU BERGAMBAR

    Directory of Open Access Journals (Sweden)

    Izhar Izhar

    2016-09-01

    Full Text Available The teacher faced problems in teaching about learning scenario containedactive learning, creativity, and pleasure. There where results from someworkshops for enhancing learning quality through learning media. However,the use of learning media did not effective in elementary level. The teacherteach in conventional way in teaching their students, the example in teachingstructure, the teacher used conventional board. Wheras, some media weremade and enhanced for learning success, such as using picture card. Throughthis media, active, creative and pleasure learning with Islamic valve will become true.Keyword: Picture card, Structure.

  5. Mechanism of coercivity enhancement by Ag addition in FePt-C granular films for heat assisted magnetic recording media

    Energy Technology Data Exchange (ETDEWEB)

    Varaprasad, B. S. D. Ch. S.; Takahashi, Y. K., E-mail: takahashi.yukiko@nims.go.jp; Wang, J.; Hono, K. [National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Ina, T.; Nakamura, T.; Ueno, W.; Nitta, K.; Uruga, T. [Japan Synchrotron Radiation Research Institute (JASRI/SPring-8), 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

    2014-06-02

    We investigated the Ag distribution in a FePtAg-C granular film that is under consideration for a heat assisted magnetic recording medium by aberration-corrected scanning transmission electron microscope-energy dispersive X-ray spectroscopy and X-ray absorption fine structure. Ag is rejected from the core of FePt grains during the deposition, forming Ag-enriched shell surrounding L1{sub 0}-ordered FePt grains. Since Ag has no solubility in both Fe and Pt, the rejection of Ag induces atomic diffusions thereby enhancing the kinetics of the L1{sub 0}-order in the FePt grains.

  6. Quantifying non-ergodic dynamics of force-free granular gases.

    Science.gov (United States)

    Bodrova, Anna; Chechkin, Aleksei V; Cherstvy, Andrey G; Metzler, Ralf

    2015-09-14

    Brownian motion is ergodic in the Boltzmann-Khinchin sense that long time averages of physical observables such as the mean squared displacement provide the same information as the corresponding ensemble average, even at out-of-equilibrium conditions. This property is the fundamental prerequisite for single particle tracking and its analysis in simple liquids. We study analytically and by event-driven molecular dynamics simulations the dynamics of force-free cooling granular gases and reveal a violation of ergodicity in this Boltzmann-Khinchin sense as well as distinct ageing of the system. Such granular gases comprise materials such as dilute gases of stones, sand, various types of powders, or large molecules, and their mixtures are ubiquitous in Nature and technology, in particular in Space. We treat-depending on the physical-chemical properties of the inter-particle interaction upon their pair collisions-both a constant and a velocity-dependent (viscoelastic) restitution coefficient ε. Moreover we compare the granular gas dynamics with an effective single particle stochastic model based on an underdamped Langevin equation with time dependent diffusivity. We find that both models share the same behaviour of the ensemble mean squared displacement (MSD) and the velocity correlations in the limit of weak dissipation. Qualitatively, the reported non-ergodic behaviour is generic for granular gases with any realistic dependence of ε on the impact velocity of particles.

  7. In situ grain fracture mechanics during uniaxial compaction of granular solids

    Science.gov (United States)

    Hurley, R. C.; Lind, J.; Pagan, D. C.; Akin, M. C.; Herbold, E. B.

    2018-03-01

    Grain fracture and crushing are known to influence the macroscopic mechanical behavior of granular materials and be influenced by factors such as grain composition, morphology, and microstructure. In this paper, we investigate grain fracture and crushing by combining synchrotron x-ray computed tomography and three-dimensional x-ray diffraction to study two granular samples undergoing uniaxial compaction. Our measurements provide details of grain kinematics, contacts, average intra-granular stresses, inter-particle forces, and intra-grain crystal and fracture plane orientations. Our analyses elucidate the complex nature of fracture and crushing, showing that: (1) the average stress states of grains prior to fracture vary widely in their relation to global and local trends; (2) fractured grains experience inter-particle forces and stored energies that are statistically higher than intact grains prior to fracture; (3) fracture plane orientations are primarily controlled by average intra-granular stress and contact fabric rather than the orientation of the crystal lattice; (4) the creation of new surfaces during fracture accounts for a very small portion of the energy dissipated during compaction; (5) mixing brittle and ductile grain materials alters the grain-scale fracture response. The results highlight an application of combined x-ray measurements for non-destructive in situ analysis of granular solids and provide details about grain fracture that have important implications for theory and modeling.

  8. Effective elasticity coefficients of native rocks and consolidated granular matter

    International Nuclear Information System (INIS)

    Schulz, Beatrix M.; Schulz, Michael

    2008-01-01

    The elastic coefficients of binary heterogeneous materials, such as several native rock materials or consolidated granular matter will be determined in terms of a perturbation expansion. Furthermore, in order to check the validity of the obtained results, these are compared with numerical investigations using Boole's model of randomly distributed spheres. Finally, we apply the results on several classes of native rocks and consolidated granular materials

  9. Spatial correlations in compressible granular flows

    NARCIS (Netherlands)

    van Noije, T.P.C.; Ernst, M.H.; Brito, R.

    The clustering instability in freely evolving granular fluids manifests itself in the density-density correlation function and structure factor. These functions are calculated from fluctuating hydrodynamics. As time increases, the structure factor of density fluctuations develops a maximum, which

  10. Microbiological aspects of granular methanogenic sludge

    NARCIS (Netherlands)

    Dolfing, J.

    1987-01-01

    The settling characteristics of anaerobic sludge are enhanced by the formation of microbial conglomerates. Various types of conglomerates having different structures, were distinguished in the present study, viz. granules, pellets and flocs (chapter 1). Granular methanogenic sludge, often

  11. Responsible use of social media by undergraduate student nurses / Ingrid van der Walt

    OpenAIRE

    Van der Walt, Ingrid

    2014-01-01

    The background and problem statement centre on the evolution of technology within teaching and learning, which involves undergraduate student nurses, as well as the use of social media as interactive teaching and communication tool. While examining the background to this topic, the researcher recognised a need to gain a deeper understanding of responsible social media use by undergraduate student nurses to the benefit of all the stakeholders, namely the Nursing Education Institution (NEI), ap...

  12. A review of Education and Social Media using conflict and functionalist theories

    Science.gov (United States)

    Cian, Heidi; Amann, Holly

    2017-09-01

    Education and Social Media: Toward a Digital Future (2016), edited by Christine Greenhow, Julia Sonnevend, and Colin Agur, is a compilation of essays by leading contributors to the digital and social media movement in education. The chapters within this volume provide a granular look at the current landscape of how digital media is utilized across educational levels, fields of study, and geographic areas. The book is divided into three sections discussing the emerging use of social media in education, challenges in its implementation, and potential directions as tech-based education continues to evolve. In this review, we situate the ideas presented in Education and Social Media in the functionalist and conflict theories of educational perspective to further illuminate the potential of digital learning in supporting increased access to education for marginalized student populations. We discuss how these competing views are both given voice in Education and Social Media, prompting the reader to critically reflect on advantages and dangers presented by increased use of technological platforms in educational settings. Topics discussed include online universities, peer-developed curriculum, and differential use of technology based on school socioeconomic demographics. We also suggest areas that have emerged in need of further discussion since the book's publication.

  13. Microservices: Granularity vs. Performance

    OpenAIRE

    Shadija, Dharmendra; Rezai, Mo; Hill, Richard

    2017-01-01

    Microservice Architectures (MA) have the potential to increase the agility of software development. In an era where businesses require software applications to evolve to support emerging software requirements, particularly for Internet of Things (IoT) applications, we examine the issue of microservice granularity and explore its effect upon application latency. Two approaches to microservice deployment are simulated; the first with microservices in a single container, and the second with micr...

  14. An Empirical Survey of Technology Application in Teaching ...

    African Journals Online (AJOL)

    The present study is very important and necessary because many teachers are ... and the extent of utilization of ICTs in instruction in Nigerian secondary schools. ... new technology in teaching and learning Geography in Nigerian Secondary ... While 42% rarely make use of multi- media presentation in teaching Geography.

  15. Anomalous infrared absorption in granular superconductors

    International Nuclear Information System (INIS)

    Carr, G.L.; Garland, J.C.; Tanner, D.B.

    1983-01-01

    Granular superconductors are shown to have a far-infrared absorption that is larger when the samples are superconducting than when they are normal. By constrast, theoretical models for these materials predict that when the samples become superconducting, the absorption should decrease

  16. The Current Use of Social Media in Undergraduate Nursing Education: A Review of the Literature.

    Science.gov (United States)

    Ross, Jennifer Gunberg; Myers, Shannon Marie

    2017-07-01

    Social media, including blogs, Twitter, wikis, Facebook, YouTube, and Ning, provides an opportunity for nurse educators to engage undergraduate nursing students who are members of the millennial generation in active learning while enhancing knowledge and fostering communication. Despite the rise of social media usage in undergraduate nursing education, there is a significant deficiency of empirical evidence supporting the efficacy and outcomes of these teaching strategies. This article provides an overview of social media use in undergraduate nursing education and a review of the existing research related to social media use in prelicensure nursing education. Overall, undergraduate nursing students respond positively to social media use in nursing education; however, no outcome measures are available to determine the effect of these teaching strategies on student learning.

  17. NMR experiments on a three-dimensional vibrofluidized granular medium

    Science.gov (United States)

    Huan, Chao; Yang, Xiaoyu; Candela, D.; Mair, R. W.; Walsworth, R. L.

    2004-04-01

    A three-dimensional granular system fluidized by vertical container vibrations was studied using pulsed field gradient NMR coupled with one-dimensional magnetic resonance imaging. The system consisted of mustard seeds vibrated vertically at 50 Hz, and the number of layers Nl⩽4 was sufficiently low to achieve a nearly time-independent granular fluid. Using NMR, the vertical profiles of density and granular temperature were directly measured, along with the distributions of vertical and horizontal grain velocities. The velocity distributions showed modest deviations from Maxwell-Boltzmann statistics, except for the vertical velocity distribution near the sample bottom, which was highly skewed and non-Gaussian. Data taken for three values of Nl and two dimensionless accelerations Γ=15,18 were fitted to a hydrodynamic theory, which successfully models the density and temperature profiles away from the vibrating container bottom. A temperature inversion near the free upper surface is observed, in agreement with predictions based on the hydrodynamic parameter μ which is nonzero only in inelastic systems.

  18. Sealing of boreholes using natural, compatible materials: Granular salt

    International Nuclear Information System (INIS)

    Finley, R.E.; Zeuch, D.H.; Stormont, J.C.; Daemen, J.J.K.

    1994-01-01

    Granular salt can be used to construct high performance permanent seals in boreholes which penetrate rock salt formations. These seals are described as seal systems comprised of the host rock, the seal material, and the seal rock interface. The performance of these seal systems is defined by the complex interactions between these seal system components through time. The interactions are largely driven by the creep of the host formation applying boundary stress on the seal forcing host rock permeability with time. The immediate permeability of these seals is dependent on the emplaced density. Laboratory test results suggest that careful emplacement techniques could results in immediate seal system permeability on the order of 10 -16 m 2 to 10 -18 m 2 (10 -4 darcy to 10 -6 ). The visco-plastic behavior of the host rock coupled with the granular salts ability to ''heal'' or consolidate make granular salt an ideal sealing material for boreholes whose permanent sealing is required

  19. Extension of PIV for measuring granular temperature field in dense fluidized beds.

    NARCIS (Netherlands)

    Dijkhuizen, W.; Bokkers, G.A.; Deen, N.G.; van Sint Annaland, M.; Kuipers, J.A.M.

    2007-01-01

    In this work a particle image velocimetry (PIV) technique has been extended to enable the simultaneous measurement of the instantaneous velocity and granular temperature fields. The PIV algorithm has been specifically optimized for dense granular systems and has been thoroughly tested with

  20. Granular corneal dystrophy

    OpenAIRE

    Castillo Pérez, Alexeide de la C; Vilches Lescaille, Daysi; Noriega, Justo Luis; Martínez Balido, Daneel; León Balbón, Bárbaro Ramón; León Bernal, Danysleidi

    2015-01-01

    Las distrofias corneales constituyen un conjunto de enfermedades que presentan, en su mayoría, una baja incidencia y se caracterizan por acúmulo de material hialino o amiloide que disminuyen la transparencia corneal. La distrofia granular es una enfermedad autosómica dominante que presenta opacidades grises en el estroma superficial central de la córnea y se hacen visibles en la primera y segunda décadas de la vida, lo que provoca disminución de la visión más significativa cerca de los 40 año...

  1. Teaching strategies applied to teaching computer networks in Engineering in Telecommunications and Electronics

    Directory of Open Access Journals (Sweden)

    Elio Manuel Castañeda-González

    2016-07-01

    Full Text Available Because of the large impact that today computer networks, their study in related fields such as Telecommunications Engineering and Electronics is presented to the student with great appeal. However, by digging in content, lacking a strong practical component, you can make this interest decreases considerably. This paper proposes the use of teaching strategies and analogies, media and interactive applications that enhance the teaching of discipline networks and encourage their study. It is part of an analysis of how the teaching of the discipline process is performed and then a description of each of these strategies is done with their respective contribution to student learning.

  2. A trans-phase granular continuum relation and its use in simulation

    Science.gov (United States)

    Kamrin, Ken; Dunatunga, Sachith; Askari, Hesam

    The ability to model a large granular system as a continuum would offer tremendous benefits in computation time compared to discrete particle methods. However, two infamous problems arise in the pursuit of this vision: (i) the constitutive relation for granular materials is still unclear and hotly debated, and (ii) a model and corresponding numerical method must wear ``many hats'' as, in general circumstances, it must be able to capture and accurately represent the material as it crosses through its collisional, dense-flowing, and solid-like states. Here we present a minimal trans-phase model, merging an elastic response beneath a fictional yield criterion, a mu(I) rheology for liquid-like flow above the static yield criterion, and a disconnection rule to model separation of the grains into a low-temperature gas. We simulate our model with a meshless method (in high strain/mixing cases) and the finite-element method. It is able to match experimental data in many geometries, including collapsing columns, impact on granular beds, draining silos, and granular drag problems.

  3. Granular deformation mechanisms in semi-solid alloys

    International Nuclear Information System (INIS)

    Gourlay, C.M.; Dahle, A.K.; Nagira, T.; Nakatsuka, N.; Nogita, K.; Uesugi, K.; Yasuda, H.

    2011-01-01

    Deformation mechanisms in equiaxed, partially solid Al-15 wt.% Cu are studied in situ by coupling shear-cell experiments with synchrotron X-ray radiography. Direct evidence is presented for granular deformation mechanisms in both globular and equiaxed-dendritic samples at solid fractions shortly after crystal impingement. It is demonstrated that dilatancy, arching and jamming occur at the crystal scale, and that these can cause stick-slip flow due to periodic dilation and compaction at low displacement rate. Granular deformation is found to be similar in globular and equiaxed-dendritic samples if length is scaled by the crystal size and packing is considered to occur among crystal envelopes. Rheological differences between the morphologies are discussed in terms of the competition between crystal rearrangement and crystal deformation.

  4. Full micromagnetics of recording on patterned media

    International Nuclear Information System (INIS)

    Fidler, J.; Schrefl, T.; Suess, D.; Ertl, O.; Kirschner, M.; Hrkac, G.

    2006-01-01

    Numerical micromagnetics of the bit writing process revealed the theoretical limits for remanence, coercive field, switching behaviour at a short time scale of less than 1 ns for patterned recording media. We discuss our recent results concerning the influence of the granular microstructure on the fast switching processes of typical CoCrPtX, FePt and CoPd thin films used for high density magnetic recording with longitudinal and perpendicular anisotropy. In detail, we will show that the degree of the exchange coupling between neighbouring grains, the grain size and its distribution and the offset between recording head and bit structure finally control the magnetization reversal properties of the individual bits

  5. Micromechanical definition of an entropy for quasi-static deformation of granular materials

    NARCIS (Netherlands)

    Rothenburg, L.; Kruyt, Nicolaas P.

    2009-01-01

    A micromechanical theory is formulated for quasi-static deformation of granular materials, which is based on information theory. A reasoning is presented that leads to the definition of an information entropy that is appropriate for quasi-static deformation of granular materials. This definition is

  6. Discrete Element study of granular material - Bumpy wall interface behavior

    Science.gov (United States)

    El Cheikh, Khadija; Rémond, Sébastien; Pizette, Patrick; Vanhove, Yannick; Djelal, Chafika

    2016-09-01

    This paper presents a DEM study of a confined granular material sheared between two parallel bumpy walls. The granular material consists of packed dry spherical particles. The bumpiness is modeled by spheres of a given diameter glued on horizontal planes. Different bumpy surfaces are modeled by varying diameter or concentration of glued spheres. The material is sheared by moving the two bumpy walls at fixed velocity. During shear, the confining pressure applied on each bumpy wall is controlled. The effect of wall bumpiness on the effective friction coefficient and on the granular material behavior at the bumpy walls is reported for various shearing conditions. For given bumpiness and confining pressure that we have studied, it is found that the shear velocity does not affect the shear stress. However, the effective friction coefficient and the behavior of the granular material depend on the bumpiness. When the diameter of the glued spheres is larger than about the average grains diameter of the medium, the latter is uniformly sheared and the effective friction coefficient remains constant. For smaller diameters of the glued spheres, the effective friction coefficient increases with the diameter of glued spheres. The influence of glued spheres concentration is significant only for small glued spheres diameters, typically half of average particle diameter of the granular material. In this case, increasing the concentration of glued spheres leads to a decrease in effective friction coefficient and to shear localization at the interface. For different diameters and concentrations of glued spheres, we show that the effect of bumpiness on the effective friction coefficient can be characterized by the depth of interlocking.

  7. Fragility and hysteretic creep in frictional granular jamming.

    Science.gov (United States)

    Bandi, M M; Rivera, M K; Krzakala, F; Ecke, R E

    2013-04-01

    The granular jamming transition is experimentally investigated in a two-dimensional system of frictional, bidispersed disks subject to quasistatic, uniaxial compression without vibrational disturbances (zero granular temperature). Three primary results are presented in this experimental study. First, using disks with different static friction coefficients (μ), we experimentally verify numerical results that predict jamming onset at progressively lower packing fractions with increasing friction. Second, we show that the first compression cycle measurably differs from subsequent cycles. The first cycle is fragile-a metastable configuration with simultaneous jammed and unjammed clusters-over a small packing fraction interval (φ(1)disk displacements over the same packing fraction interval. This fragile behavior is explained through a percolation mechanism of stressed contacts where cluster growth exhibits spatial correlation with disk displacements and contributes to recent results emphasizing fragility in frictional jamming. Control experiments show that the fragile state results from the experimental incompatibility between the requirements for zero friction and zero granular temperature. Measurements with several disk materials of varying elastic moduli E and friction coefficients μ show that friction directly controls the start of the fragile state but indirectly controls the exponential pressure rise. Finally, under repetitive loading (compression) and unloading (decompression), we find the system exhibits pressure hysteresis, and the critical packing fraction φ(c) increases slowly with repetition number. This friction-induced hysteretic creep is interpreted as the granular pack's evolution from a metastable to an eventual structurally stable configuration. It is shown to depend on the quasistatic step size Δφ, which provides the only perturbative mechanism in the experimental protocol, and the friction coefficient μ, which acts to stabilize the pack.

  8. Variasi Media Dalam Menajarkan Calistung Di Raudlatul Athfal Babul Jannah Sambas

    Directory of Open Access Journals (Sweden)

    Sigit Purnama

    2016-12-01

    Full Text Available Calistung (reading, writing and numeracy learning in early childhood controversy among the public because it is considered a bad impact on child's mental. RA Babul Jannah Sambas is one of the early childhood institutions that implement Calistung learning in early childhood by applying a variety of media learning. This study aims to describe empirically the use of variations of instructional media in teaching Calistung in RA Babul Jannah Sambas. This research use qualitative approach with data collecting technique through interview, observation and documentation. The results of this study concluded that: 1 the media is varied, i.e. human, APE, and programs/activities. Techniques variety of media consisting of: a vary some of the learning media in all meetings, b varying one media with several learning methods, c use different media every day, d using the media in the time index, and e varying the use of media outside the classroom. Whereas, the activities of the variety of media in the learning process consists of planning, preparation, implementation and evaluation; 2 the use of a variety of instructional media in teaching Calistung have a considerable impact both on the development of early childhood; 3 the advantages of the use of a variety of media including sparking the interest and attention of the child, train the skills Calistung, and minimize the flavor saturated and bored. While, the drawback is the need to provide different media every day, while the number of media available is very limited. The efforts of teachers in overcoming the shortcomings, such as the teacher using the division of the group and turn in a media play.

  9. Social Media and the New Academic Environment: Pedagogical Challenges

    Science.gov (United States)

    Patrut, Bogdan; Patrut, Monica; Cmeciu, Camelia

    2013-01-01

    As web applications play a vital role in our society, social media has emerged as an important tool in the creation and exchange of user-generated content and social interaction. The benefits of these services have entered in the educational areas to become new means by which scholars communicate, collaborate and teach. Social Media and the New…

  10. Numerical insight into the micromechanics of jet erosion of a cohesive granular material

    Directory of Open Access Journals (Sweden)

    Cuéllar Pablo

    2017-01-01

    Full Text Available Here we investigate the physical mechanisms behind the surface erosion of a cohesive granular soil induced by an impinging jet by means of numerical simulations coupling fluid and grains at the microscale. The 2D numerical model combines the Discrete Element and Lattice Boltzmann methods (DEM-LBM and accounts for the granular cohesion with a contact model featuring a paraboloidal yield surface. Here we review first the hydrodynamical conditions imposed by the fluid jet on a solid granular packing, turning then the attention to the impact of cohesion on the erosion kinetics. Finally, the use of an additional subcritical debonding damage model based on the work of Silvani and co-workers provides a novel insight into the internal solicitation of the cohesive granular sample by the impinging jet.

  11. Numerical insight into the micromechanics of jet erosion of a cohesive granular material

    Science.gov (United States)

    Cuéllar, Pablo; Benseghier, Zeyd; Luu, Li-Hua; Bonelli, Stéphane; Delenne, Jean-Yves; Radjaï, Farhang; Philippe, Pierre

    2017-06-01

    Here we investigate the physical mechanisms behind the surface erosion of a cohesive granular soil induced by an impinging jet by means of numerical simulations coupling fluid and grains at the microscale. The 2D numerical model combines the Discrete Element and Lattice Boltzmann methods (DEM-LBM) and accounts for the granular cohesion with a contact model featuring a paraboloidal yield surface. Here we review first the hydrodynamical conditions imposed by the fluid jet on a solid granular packing, turning then the attention to the impact of cohesion on the erosion kinetics. Finally, the use of an additional subcritical debonding damage model based on the work of Silvani and co-workers provides a novel insight into the internal solicitation of the cohesive granular sample by the impinging jet.

  12. Jamming and chaotic dynamics in different granular systems

    Science.gov (United States)

    Maghsoodi, Homayoon; Luijten, Erik

    Although common in nature and industry, the jamming transition has long eluded a concrete, mechanistic explanation. Recently, Banigan et al. (Nat. Phys. 9, 288-292, 2013) proposed a method for characterizing this transition in a granular system in terms of the system's chaotic properties, as quantified by the largest Lyapunov exponent. They demonstrated that in a two-dimensional shear cell the jamming transition coincides with the bulk density at which the system's largest Lyapunov exponent changes sign, indicating a transition between chaotic and non-chaotic regimes. To examine the applicability of this observation to realistic granular systems, we study a model that includes frictional forces within an expanded phase space. Furthermore, we test the generality of the relation between chaos and jamming by investigating the relationship between jamming and the chaotic properties of several other granular systems, notably sheared systems (Howell, D., Behringer R. P., Veje C., Phys. Rev. Lett. 82, 5241-5244, 1999) and systems with a free boundary. Finally, we quantify correlations between the largest Lyapunov vector and collective rearrangements of the system to demonstrate the predictive capabilities enabled by adopting this perspective of jamming.

  13. Compliant contact versus rigid contact: A comparison in the context of granular dynamics

    Science.gov (United States)

    Pazouki, Arman; Kwarta, Michał; Williams, Kyle; Likos, William; Serban, Radu; Jayakumar, Paramsothy; Negrut, Dan

    2017-10-01

    We summarize and numerically compare two approaches for modeling and simulating the dynamics of dry granular matter. The first one, the discrete-element method via penalty (DEM-P), is commonly used in the soft matter physics and geomechanics communities; it can be traced back to the work of Cundall and Strack [P. Cundall, Proc. Symp. ISRM, Nancy, France 1, 129 (1971); P. Cundall and O. Strack, Geotechnique 29, 47 (1979), 10.1680/geot.1979.29.1.47]. The second approach, the discrete-element method via complementarity (DEM-C), considers the grains perfectly rigid and enforces nonpenetration via complementarity conditions; it is commonly used in robotics and computer graphics applications and had two strong promoters in Moreau and Jean [J. J. Moreau, in Nonsmooth Mechanics and Applications, edited by J. J. Moreau and P. D. Panagiotopoulos (Springer, Berlin, 1988), pp. 1-82; J. J. Moreau and M. Jean, Proceedings of the Third Biennial Joint Conference on Engineering Systems and Analysis, Montpellier, France, 1996, pp. 201-208]. The DEM-P and DEM-C are manifestly unlike each other: They use different (i) approaches to model the frictional contact problem, (ii) sets of model parameters to capture the physics of interest, and (iii) classes of numerical methods to solve the differential equations that govern the dynamics of the granular material. Herein, we report numerical results for five experiments: shock wave propagation, cone penetration, direct shear, triaxial loading, and hopper flow, which we use to compare the DEM-P and DEM-C solutions. This exercise helps us reach two conclusions. First, both the DEM-P and DEM-C are predictive, i.e., they predict well the macroscale emergent behavior by capturing the dynamics at the microscale. Second, there are classes of problems for which one of the methods has an advantage. Unlike the DEM-P, the DEM-C cannot capture shock-wave propagation through granular media. However, the DEM-C is proficient at handling arbitrary grain

  14. Some exact velocity profiles for granular flow in converging hoppers

    Science.gov (United States)

    Cox, Grant M.; Hill, James M.

    2005-01-01

    Gravity flow of granular materials through hoppers occurs in many industrial processes. For an ideal cohesionless granular material, which satisfies the Coulomb-Mohr yield condition, the number of known analytical solutions is limited. However, for the special case of the angle of internal friction δ equal to ninety degrees, there exist exact parametric solutions for the governing coupled ordinary differential equations for both two-dimensional wedges and three-dimensional cones, both of which involve two arbitrary constants of integration. These solutions are the only known analytical solutions of this generality. Here, we utilize the double-shearing theory of granular materials to determine the velocity field corresponding to these exact parametric solutions for the two problems of gravity flow through converging wedge and conical hoppers. An independent numerical solution for other angles of internal friction is shown to coincide with the analytical solution.

  15. Cutting-Edge Technologies and Social Media Use in Higher Education

    Science.gov (United States)

    Benson, Vladlena, Ed.; Morgan, Stephanie

    2014-01-01

    The inclusion of social media in higher education has transformed the way instructors teach and students learn. In order to effectively reach their students in this networked world, teachers must learn to utilize the latest technologies in their classrooms. "Cutting-Edge Technologies and Social Media Use in Higher Education" brings…

  16. Kovacs-Like Memory Effect in Driven Granular Gases

    Science.gov (United States)

    Prados, A.; Trizac, E.

    2014-05-01

    While memory effects have been reported for dense enough disordered systems such as glasses, we show here by a combination of analytical and simulation techniques that they are also intrinsic to the dynamics of dilute granular gases. By means of a certain driving protocol, we prepare the gas in a state where the granular temperature T coincides with its long time limit. However, T does not subsequently remain constant but exhibits a nonmonotonic evolution before reaching its nonequilibrium steady value. The corresponding so-called Kovacs hump displays a normal behavior for weak dissipation (as observed in molecular systems) but is reversed under strong dissipation, where it, thus, becomes anomalous.

  17. A new method for measurement of granular velocities

    International Nuclear Information System (INIS)

    Nyborg Andersen, B.

    1984-01-01

    A new, supplementary method to measure granular velocities is presented. The method utilizes the Doppler shift caused by the line of sight component of the solar rotation to cause a wavelength shift through spectral lines as function of heliocentric angle. By measuring the center-to-limb variation of the granular intensity fluctations at different wavelength positions in the lines, the velocities are found. To do this, assumptions regarding the geometrical structure of the velocity and intensity fields have to be made. Preliminary application of the method results in a steep velocity gradient suggesting zero velocity at a hight of 200 km above tau 500 = 1. Possible causes are discussed

  18. Multi-scale mechanics of granular solids from grain-resolved X-ray measurements

    Science.gov (United States)

    Hurley, R. C.; Hall, S. A.; Wright, J. P.

    2017-11-01

    This work discusses an experimental technique for studying the mechanics of three-dimensional (3D) granular solids. The approach combines 3D X-ray diffraction and X-ray computed tomography to measure grain-resolved strains, kinematics and contact fabric in the bulk of a granular solid, from which continuum strains, grain stresses, interparticle forces and coarse-grained elasto-plastic moduli can be determined. We demonstrate the experimental approach and analysis of selected results on a sample of 1099 stiff, frictional grains undergoing multiple uniaxial compression cycles. We investigate the inter-particle force network, elasto-plastic moduli and associated length scales, reversibility of mechanical responses during cyclic loading, the statistics of microscopic responses and microstructure-property relationships. This work serves to highlight both the fundamental insight into granular mechanics that is furnished by combined X-ray measurements and describes future directions in the field of granular materials that can be pursued with such approaches.

  19. Removal of oxytetracycline and determining its biosorption properties on aerobic granular sludge.

    Science.gov (United States)

    Mihciokur, Hamdi; Oguz, Merve

    2016-09-01

    This study investigates biosorption of Oxytetracycline, a broad-spectrum antibiotic, using aerobic granular sludge as an adsorbent in aqueous solutions. A sequencing batch reactor fed by a synthetic wastewater was operated to create aerobic granular sludge. Primarily, the pore structure and surface area of granular sludge, the chemical structure and the molecular sizes of the pharmaceutical, operating conditions, such as pH, stirring rate, initial concentration of Oxytetracycline, during adsorption process was verified. Subsequently, thermodynamic and kinetic aspects of the adsorption were examined and adsorption isotherm studies were carried out. It was shown that the aerobic granular sludge was a good alternative for biosorption of this pharmaceutical. The pharmaceutical was adsorbed better at pH values of 6-8. The adsorption efficiency increased with rising ionic strength. Also, it was seen that the adsorption process was an exothermic process in terms of thermodynamics. The adsorption can be well explained by Langmuir isotherm model. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Simultaneous Cr(VI) bio-reduction and methane production by anaerobic granular sludge.

    Science.gov (United States)

    Hu, Qian; Sun, Jiaji; Sun, Dezhi; Tian, Lan; Ji, Yanan; Qiu, Bin

    2018-08-01

    Wastewater containing toxic hexavalent chromium (Cr(VI)) were treated with well-organized anaerobic granular sludge in this study. Results showed that the anaerobic granular sludge rapidly removed Cr(VI), and 2000 µg·L -1 Cr(VI) was completely eliminated within 6 min, which was much faster than the reported duration of removal by reported artificial materials. Sucrose added as a carbon source acted as an initial electron donor to reduce Cr(VI) to Cr(III). This process was considered as the main mechanism of Cr(VI) removal. Methane production by anaerobic granular sludge was improved by the addition of Cr(VI) at a concentration lower than 500 µg·L -1 . Anaerobic granular sludge had a well-organized structure, which presented good resistance against toxic Cr(VI). Trichoccus accelerated the degradation of organic substances to generate acetates with a low Cr(VI) concentration, thereby enhancing methane production by acetotrophic methanogens. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Tunable evolutions of shock absorption and energy partitioning in magnetic granular chains

    Science.gov (United States)

    Leng, Dingxin; Liu, Guijie; Sun, Lingyu

    2018-01-01

    In this paper, we investigate the tunable characteristics of shock waves propagating in one-dimensional magnetic granular chains at various chain lengths and magnetic flux densities. According to the Hertz contact theory and Maxwell principle, a discrete element model with coupling elastic and field-induced interaction potentials of adjacent magnetic grains is proposed. We also present hard-sphere approximation analysis to describe the energy partitioning features of magnetic granular chains. The results demonstrate that, for a fixed magnetic field strength, when the chain length is greater than two times of the wave width of the solitary wave, the chain length has little effect on the output energy of the system; for a fixed chain length, the shock absorption and energy partitioning features of magnetic granular chains are remarkably influenced by varying magnetic flux densities. This study implies that the magnetic granular chain is potential to construct adaptive shock absorption components for impulse mitigation.

  2. Iodine Gas Trapping using Granular Porous Bismuth

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jae Hwan; Shin, Jin Myeong; Park, Jang Jin; Park, Geun Il [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Yim, Mansung [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    {sup 129}I is a radionuclide with a very long half-life of 1.57 Χ 10{sup 7} years and has negative health effects to the human body. Therefore, the emission of {sup 129}I into the air is closely regulated by the Environmental Protection Agency (EPA). Many methods for trapping gaseous {sup 129}I have been developed thus far, including wet scrubbing and adsorption using silver loaded zeolites. Although wet scrubbing can effectively remove iodine, it suffers from corrosion of the vessel due to high concentration of the scrubbing solution. Silver loaded zeolites also show effectiveness in capturing {sup 129}I gas, yet weak thermal stability of physisorbed iodine remains a challenge. We studied a novel and facile method to trap iodine gas using bismuth. Granular bismuth having many pores was synthesized using bismuth nitrate and polyvinyl alcohol as a bismuth precursor and pore forming agent, respectively. Reaction of iodine and our samples resulted in an iodine capturing capacity of more than 2 times that of the commercial grade silver exchanged zeolite (AgX). Granular porous bismuths synthesized using bismuth nitrate and PVA show a promising performance in capturing iodine gas. The use of bismuth in trapping {sup 129}I gas can reduce the process cost as bismuth is cheap. Further study is going on to improve the mechanical property of granular porous bismuths for their easy handling.

  3. Iodine Gas Trapping using Granular Porous Bismuth

    International Nuclear Information System (INIS)

    Yang, Jae Hwan; Shin, Jin Myeong; Park, Jang Jin; Park, Geun Il; Yim, Mansung

    2014-01-01

    129 I is a radionuclide with a very long half-life of 1.57 Χ 10 7 years and has negative health effects to the human body. Therefore, the emission of 129 I into the air is closely regulated by the Environmental Protection Agency (EPA). Many methods for trapping gaseous 129 I have been developed thus far, including wet scrubbing and adsorption using silver loaded zeolites. Although wet scrubbing can effectively remove iodine, it suffers from corrosion of the vessel due to high concentration of the scrubbing solution. Silver loaded zeolites also show effectiveness in capturing 129 I gas, yet weak thermal stability of physisorbed iodine remains a challenge. We studied a novel and facile method to trap iodine gas using bismuth. Granular bismuth having many pores was synthesized using bismuth nitrate and polyvinyl alcohol as a bismuth precursor and pore forming agent, respectively. Reaction of iodine and our samples resulted in an iodine capturing capacity of more than 2 times that of the commercial grade silver exchanged zeolite (AgX). Granular porous bismuths synthesized using bismuth nitrate and PVA show a promising performance in capturing iodine gas. The use of bismuth in trapping 129 I gas can reduce the process cost as bismuth is cheap. Further study is going on to improve the mechanical property of granular porous bismuths for their easy handling

  4. Social Media, Collaboration and Social Learning

    DEFF Research Database (Denmark)

    Mondahl, Margrethe; Razmerita, Liana

    2014-01-01

    Social media has created new possibilities for digitally native students to engage, interact and collaborate in learning tasks that foster learning processes and the overall learning experience. Using both qualitative and quantitative data, this article discusses experiences and challenges of using...... a social media-enhanced collaborative learning environment in case-based teaching of foreign languages. Based on social constructivismwe argue that foreign language learning is an individual as well as collaborative process and cognitive processes underlying learning and in particular foreign language...... learning are facilitated by means of social media and especially for new generation of students. This article contributes to understanding of how best to make use of social media in an educational setting and how learning may be fostered in social, collaborative knowledge construction, sharing and building...

  5. Social Media Ethics in English Language Teaching

    Science.gov (United States)

    Blyth, Andrew

    2015-01-01

    Many teachers are increasingly using Social Networking Services (SNS) in their classrooms, which allows for the first time the outside world to peer into students' private learning spaces (Blyth, 2011). However, the adoption of social media has mostly been done without careful consideration of possible ramifications students may suffer.…

  6. DEVELOPMENT OF STUDENTS’ MEDIA LITERACY IN THE PROCESS OF CREATING SCHOOL MEDIA

    Directory of Open Access Journals (Sweden)

    Julia Rybina

    2017-04-01

    Full Text Available Nowadays, a rapid development of information and communication technologies enables combine a number of formats for presenting information into one communication unit. That is why the media (Internet especially is not just tools for young generation for learning the modern world. Children enjoy in dealing with modern technologies. However not everyone has sufficient skills to objectively assess the true meaning of the information received. That is why children are more inclined for their mind to be manipulated and they are more inclined for blind imitating of attractive images. Owning to the above, the most priority-driven of modern education is the usage of information and communication technologies and media education for forming the skills of students' orientation in the information field and for forming the development of media immunity of the personality which makes the personality able to resist to the aggressive media space. Teachers face the challenge of introducing media education in middle and high schools. To implement the media education at the municipal institution regional specialized residential school “Giftedness” the pedagogical experiment was carried out there. The basis of the experiment is the generalized model of media literacy development for students that was used during for making and functioning the school newspaper «D.A.R-media». Theoretical aspects of the implementation of media education in the teaching and educational process of a specialized educational institution are considered in this study. A model for the development of the media literacy of students in the process of creating a school printed publication is proposed. Some results of research on the level of media literacy of students are highlighted and prospects for work on introducing media education of teachers and teachers are outlined.

  7. Bedrock erosion by sliding wear in channelized granular flow

    Science.gov (United States)

    Hung, C. Y.; Stark, C. P.; Capart, H.; Smith, B.; Maia, H. T.; Li, L.; Reitz, M. D.

    2014-12-01

    Boundary forces generated by debris flows can be powerful enough to erode bedrock and cause considerable damage to infrastructure during runout. Bedrock wear can be separated into impact and sliding wear processes. Here we focus on sliding wear. We have conducted experiments with a 40-cm-diameter grainflow-generating rotating drum designed to simulate dry channelized debris flows. To generate sliding erosion, we placed a 20-cm-diameter bedrock plate axially on the back wall of the drum. The rotating drum was half filled with 2.3-mm-diameter grains, which formed a thin grain-avalanching layer with peak flow speed and depth close to the drum axis. The whole experimental apparatus was placed on a 100g-ton geotechnical centrifuge and, in order to scale up the stress level, spun to a range of effective gravity levels. Rates and patterns of erosion of the bedrock plate were mapped after each experiment using 3d micro-photogrammetry. High-speed video and particle tracking were employed to measure granular flow dynamics. The resulting data for granular velocities and flow geometry were used to estimate impulse exchanges and forces on the bedrock plate. To address some of the complexities of granular flow under variable gravity levels, we developed a continuum model framed around a GDR MiDi rheology. This model allowed us to scale up boundary forcing while maintaining the same granular flow regime, and helped us to understand important aspects of the flow dynamics including e.g. fluxes of momentum and kinetic energy. In order to understand the detailed processes of boundary forcing, we performed numerical simulations with a new contact dynamics model. This model confirmed key aspects of our continuum model and provided information on second-order behavior such as fluctuations in the forces acting on the wall. By combining these measurements and theoretical analyses, we have developed and calibrated a constitutive model for sliding wear that is a threshold function of

  8. Contact force structure and force chains in 3D sheared granular systems

    Science.gov (United States)

    Mair, Karen; Jettestuen, Espen; Abe, Steffen

    2010-05-01

    Faults often exhibit accumulations of granular debris, ground up to create a layer of rock flour or fault gouge separating the rigid fault walls. Numerical simulations and laboratory experiments of sheared granular materials, suggest that applied loads are preferentially transmitted across such systems by transient force networks that carry enhanced forces. The characterisation of such features is important since their nature and persistence almost certainly influence the macroscopic mechanical stability of these systems and potentially that of natural faults. 3D numerical simulations of granular shear are a valuable investigation tool since they allow us to track individual particle motions, contact forces and their evolution during applied shear, that are difficult to view directly in laboratory experiments or natural fault zones. In characterising contact force distributions, it is important to use global structure measures that allow meaningful comparisons of granular systems having e.g. different grain size distributions, as may be expected at different stages of a fault's evolution. We therefore use a series of simple measures to characterise the structure, such as distributions and correlations of contact forces that can be mapped onto a force network percolation problem as recently proposed by Ostojic and coworkers for 2D granular systems. This allows the use of measures from percolation theory to both define and characterise the force networks. We demonstrate the application of this method to 3D simulations of a sheared granular material. Importantly, we then compare our measure of the contact force structure with macroscopic frictional behaviour measured at the boundaries of our model to determine the influence of the force networks on macroscopic mechanical stability.

  9. Nitrate adsorption from aqueous solution using granular chitosan-Fe{sup 3+} complex

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Qili [School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083 (China); Key Laboratory of Groundwater Cycle and Environment Evolution,China University of Geosciences (Beijing), Ministry of Education, Beijing, 100083 (China); Chen, Nan, E-mail: chennan@cugb.edu.cn [School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083 (China); Key Laboratory of Groundwater Cycle and Environment Evolution, China University of Geosciences (Beijing), Ministry of Education, Beijing, 100083 (China); Feng, Chuanping [School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083 (China); Key Laboratory of Groundwater Cycle and Environment Evolution, China University of Geosciences (Beijing), Ministry of Education, Beijing, 100083 (China); Hu, WeiWu [The Journal Center, China University of Geosciences (Beijing), Beijing, 100083 (China)

    2015-08-30

    Highlights: • Granular chitosan-Fe{sup 3+} complex had high performance for nitrate adsorption. • Granular chitosan-Fe{sup 3+} complex had shorter equilibrium time (1.5 h). • Nitrate adsorption was ascribed to ion exchange and electrostatic attraction. • Granular chitosan-Fe{sup 3+} complex could be regenerated using NaCl solution. - Abstract: In the present study, In order to efficiently remove nitrate, granular chitosan-Fe{sup 3+} complex with high chemical stability and good environmental adaptation was synthesized through precipitation method and characterized using SEM, XRD, BET and FTIR. The nitrate adsorption performance was evaluated by batch experiments. The results indicated that granular chitosan-Fe{sup 3+} complex was an amorphous and mesoporous material. The BET specific surface area and average pore size were 8.98 m{sup 2} g{sup −1} and 56.94 Å, respectively. The point of zero charge was obtained at pH 5. The maximum adsorption capacity reached 8.35 mg NO{sub 3}{sup −}-N g{sup −1} based on Langmuir–Freundlich model. Moreover, no significant change in the nitrate removal efficiency was observed in the pH range of 3.0–10.0. The adverse influence of sulphate on nitrate removal was the most significant, followed by bicarbonate and fluoride, whereas chloride had slightly adverse effect. Adsorption process followed the pseudo-second-order kinetic model, and the experimental equilibrium data were fitted well with the Langmuir–Freundlich and D–R isotherm models. Thermodynamic parameters revealed that nitrate adsorption was a spontaneous and exothermic process. Granular chitosan-Fe{sup 3+} complex could be effectively regenerated by NaCl solution.

  10. Mobile Inverted Constructivism: Education of Interaction Technology in Social Media

    Science.gov (United States)

    Chai, Jia-Xiang; Fan, Kuo-Kuang

    2016-01-01

    The combination of social media and invert teaching is a new path to inverting interation technology education and reconstructing the curriculum of context. In this paper, based on the theory of constructivism learning, a model named Mobile Inverted Constructivism (MIC) is provided. Moreover, in view of the functional quality of social media in…

  11. Lift on side by side intruders of various geometries within a granular flow

    Science.gov (United States)

    Acevedo-Escalante, M. F.; Caballero-Robledo, G. A.

    2017-06-01

    Obstacles within fluids have been widely used in engineering and in physics to study hydrodynamic interactions. In granular matter, objects within a granular flow have helped to understand fundamental features of drag and lift forces. In our group, we have studied numerically the flow mediated interaction between two static disks within a vertical granular flow in a two-dimensional container where the flow velocity and the distance between obstacles were varied. Attractive and repulsive forces were found depending on flow velocity and separation between intruders. The simulations evidenced a relationship between the average flow velocity in a specific section ahead of the obstacles and the attractive-repulsive lift. On the other hand, it was showed that the lift force on an object dragged within a granular medium depends on the shape of the intruder. Here we present experimental results of the interaction between two side-by-side intruders of different shapes within a vertical granular flow. We built a quasi-two-dimensional container in which we placed the intruders and using load cells we measured lift and drag forces during the discharge process for different flow velocities.

  12. Pemanfaatan Media Cetak dalam Pembelajaran IPS di Sekolah Dasar

    Directory of Open Access Journals (Sweden)

    Hadi Mustofa

    2016-02-01

    Full Text Available This study was designed to know the use of printed media in teaching Social Studies. It involved 15 teachers of 5th grade of elementary school and focused on their strategy on utilizing a printed media. The data were collected by interview, questionnaire, and observation, and were then analyzed statistically by percentages. The finding shows that the teachers utilize textbooks, newspaper, magazines, and pictures in their instructions. The process includes planning, implementation, and evaluation of media utilization

  13. The influence of the fractal particle size distribution on the mobility of dry granular materials

    Directory of Open Access Journals (Sweden)

    Vallejo Luis E.

    2017-01-01

    Full Text Available This study presents an experimental analysis on the influence of the particle size distribution (psd on the mobility of dry granular materials. The psd obeys a power law of the form: N(L>d=kd-Df, where N is the number of particles with diameter L greater than a given diameter d, k is a proportionality constant, and Df is the fractal dimension of the psd. No laboratory or numerical study has been conducted to date analysing how a fractal psd influences the mobility of granular flows as in the case of rock avalanches. In this study, the flow characteristics of poly-dispersed granular materials that have a fractal psd were investigated in the laboratory. Granular mixtures having different fractal psd values were placed in a hollow cylinder. The cylinder was lifted and the distance of flow of the mixture was measured with respect to the original position of the cylinder. It was determined that the distance of flow of the mixtures was directly related to their fractal psd values. That is, the larger the distance of flow of the mixture, the larger is the fractal psd of the granular mixture tested. Thus, the fractal psd in dry granular mixtures seems to have a large influence on the easiness by which dry granular mixtures move in the field.

  14. Memory effect in uniformly heated granular gases

    Science.gov (United States)

    Trizac, E.; Prados, A.

    2014-07-01

    We evidence a Kovacs-like memory effect in a uniformly driven granular gas. A system of inelastic hard particles, in the low density limit, can reach a nonequilibrium steady state when properly forced. By following a certain protocol for the drive time dependence, we prepare the gas in a state where the granular temperature coincides with its long time value. The temperature subsequently does not remain constant but exhibits a nonmonotonic evolution with either a maximum or a minimum, depending on the dissipation and on the protocol. We present a theoretical analysis of this memory effect at Boltzmann-Fokker-Planck equation level and show that when dissipation exceeds a threshold, the response can be called anomalous. We find excellent agreement between the analytical predictions and direct Monte Carlo simulations.

  15. Evaluating Energy Flux in Vibrofluidized Granular Bed

    Directory of Open Access Journals (Sweden)

    N. A. Sheikh

    2013-01-01

    Full Text Available Granular flows require sustained input of energy for fluidization. A level of fluidization depends on the amount of heat flux provided to the flow. In general, the dissipation of the grains upon interaction balances the heat inputs and the resultant flow patterns can be described using hydrodynamic models. However, with the increase in packing fraction, the heat fluxes prediction of the cell increases. Here, a comparison is made for the proposed theoretical models against the MD simulations data. It is observed that the variation of packing fraction in the granular cell influences the heat flux at the base. For the elastic grain-base interaction, the predictions vary appreciably compared to MD simulations, suggesting the need to accurately model the velocity distribution of grains for averaging.

  16. ENGINEERING BULLETIN: GRANULAR ACTIVATED CARBON TREATMENT

    Science.gov (United States)

    Granular activated carbon (GAC) treatment is a physicochemical process that removes a wide variety of contaminants by adsorbing them from liquid and gas streams [1, p. 6-3]. This treatment is most commonly used to separate organic contaminants from water or air; however, it can b...

  17. Velocity distributions in dilute granular systems

    NARCIS (Netherlands)

    van Zon, J.S.; Mac Kintosh, F.C.

    2005-01-01

    We investigate the idea that velocity distributions in granular gases are determined mainly by η, the coefficient of restitution and q, which measures the relative importance of heating (or energy input) to collisions. To this end, we study by numerical simulation the properties of inelastic gases

  18. Granular cell tumor of the esophagus. Report of three cases.

    Science.gov (United States)

    Cohle, S D; McKechnie, J C; Truong, L; Jurco, S

    1981-06-01

    Granular cell tumors, (formerly called myoblastomas) involving the esophagus were encountered in three patients. In all three the tumors were asymptomatic and in two they were multiple. The first published endoscopic photographs of such a tumor are presented. The successful total removal of this neoplasm using the endoscope is described. The pathologic, radiologic and therapeutic aspects of previously reported cases of granular cell tumor of the esophagus are reviewed and compared with the three reported herein.

  19. Experimental study of energy exchanges between two coupled granular gases

    OpenAIRE

    Chastaing , J.-Y; Géminard , J.-C; Naert , A

    2016-01-01

    International audience; We report on the energy exchanges between two granular gases of different densities coupled electrome-chanically by immersed blades attached to dc motors. Zeroing the energy flux between the two subsystems, we demonstrate that an immersed blade is a convenient way to assess the properties of the granular gases, provided that the dissipation in the motor is properly taken into account. In addition, when the two gases have different densities, the fluctuations of the ene...

  20. Experimental investigation of granular dynamics close to the jamming transition

    Science.gov (United States)

    Caballero, G.; Kolb, E.; Lindner, A.; Lanuza, J.; Clément, E.

    2005-06-01

    We present different experiments on dense granular assemblies with the aim of clarifying the notion of 'jamming transition' for these assemblies of non-Brownian particles. The experimental set-ups differ in the way in which external perturbations are applied in order to unjam the systems. The first experiment monitors the response to a locally applied deformation of a model packing at rest. The two other experiments study local and collective dynamics in a granular assembly weakly excited by vibration.

  1. Dynamic aerofracture or hydrofracture of dense granular packing: pressure and viscosity control of the fracture patterns

    Science.gov (United States)

    Niebling, Michael J.; Toussaint, Renaud; Flekkøy, Eirik G.; Jørgen Måløy, Knut

    2013-04-01

    øy and K.J. Måløy, Dynamic aerofracture of dense granular packings, Phys. Rev. E 86, 061315 (2012). [4] Niebling, M., R. Toussaint, E.G. Flekkøy and K.J. Måløy, Estudios numéricos de Aerofractures en medios poros / Numerical Studies of Aerofractures in Porous Media, Revista Cubana de Fisica, 29, 1E, 1E66, 2012.

  2. Fine-granularity inference and estimations to network traffic for SDN.

    Directory of Open Access Journals (Sweden)

    Dingde Jiang

    Full Text Available An end-to-end network traffic matrix is significantly helpful for network management and for Software Defined Networks (SDN. However, the end-to-end network traffic matrix's inferences and estimations are a challenging problem. Moreover, attaining the traffic matrix in high-speed networks for SDN is a prohibitive challenge. This paper investigates how to estimate and recover the end-to-end network traffic matrix in fine time granularity from the sampled traffic traces, which is a hard inverse problem. Different from previous methods, the fractal interpolation is used to reconstruct the finer-granularity network traffic. Then, the cubic spline interpolation method is used to obtain the smooth reconstruction values. To attain an accurate the end-to-end network traffic in fine time granularity, we perform a weighted-geometric-average process for two interpolation results that are obtained. The simulation results show that our approaches are feasible and effective.

  3. Fine-granularity inference and estimations to network traffic for SDN.

    Science.gov (United States)

    Jiang, Dingde; Huo, Liuwei; Li, Ya

    2018-01-01

    An end-to-end network traffic matrix is significantly helpful for network management and for Software Defined Networks (SDN). However, the end-to-end network traffic matrix's inferences and estimations are a challenging problem. Moreover, attaining the traffic matrix in high-speed networks for SDN is a prohibitive challenge. This paper investigates how to estimate and recover the end-to-end network traffic matrix in fine time granularity from the sampled traffic traces, which is a hard inverse problem. Different from previous methods, the fractal interpolation is used to reconstruct the finer-granularity network traffic. Then, the cubic spline interpolation method is used to obtain the smooth reconstruction values. To attain an accurate the end-to-end network traffic in fine time granularity, we perform a weighted-geometric-average process for two interpolation results that are obtained. The simulation results show that our approaches are feasible and effective.

  4. Structural evolution of a granular medium during simultaneous penetration

    Science.gov (United States)

    González-Gutiérrez, Jorge; Carreón, Yojana J. P.; Moctezuma, R. E.

    2018-01-01

    Typically, fluidized beds are granular systems composed of solid particles through which a fluid flows. They are relevant to a wide variety of disciplines such as physics, chemistry, engineering, among others. Generally, the fluidized beds are characterized by different flow regimes such as particulate, bubbling, slugging, turbulent, fast fluidization, and pneumatic conveying. Here, we report the experimental study of the structural evolution of a granular system due to simultaneous penetration of intruders in the presence of an upward airflow. We found that the granular medium evolves from the static state to the turbulent regime showing the coexistence of three regions in different flow regimes. Interestingly, the cooperative dynamic of intruders correlate with the formation of such regions. As a non-invasive method, we use lacunarity and fractal dimension to quantitatively describe the patterns arising within the system during the different stages of the penetration process. Finally, we found that our results would allow us to relate the evolution of the visual patterns appearing in the process with different physical properties of the system.

  5. Analysis of Cylindrical Granular Material Silos under Seismic Excitation

    Directory of Open Access Journals (Sweden)

    Christoph Butenweg

    2017-07-01

    Full Text Available Silos generally work as storage structures between supply and demand for various goods, and their structural safety has long been of interest to the civil engineering profession. This is especially true for dynamically loaded silos, e.g., in case of seismic excitation. Particularly thin-walled cylindrical silos are highly vulnerable to seismic induced pressures, which can cause critical buckling phenomena of the silo shell. The analysis of silos can be carried out in two different ways. In the first, the seismic loading is modeled through statically equivalent loads acting on the shell. Alternatively, a time history analysis might be carried out, in which nonlinear phenomena due to the filling as well as the interaction between the shell and the granular material are taken into account. The paper presents a comparison of these approaches. The model used for the nonlinear time history analysis considers the granular material by means of the intergranular strain approach for hypoplasticity theory. The interaction effects between the granular material and the shell is represented by contact elements. Additionally, soil–structure interaction effects are taken into account.

  6. Social Media as Source of Medical Information for Healthcare Students

    Directory of Open Access Journals (Sweden)

    Ariana Anamaria CORDOȘ

    2016-03-01

    Full Text Available Introduction: The scope of the research was a more detailed understanding of the influence of social media and the importance of student’s usage of social media context in relation to medical information. The research aimed to increase the understanding of social media and the impact on medical information use, informing policy and practice while highlighting gaps in the literature and areas for further research. Methods: The search of PubMed database was performed in October 2015, using terms to identify peer-reviewed research in which social media technologies were an important feature for health occupations, premedical, pharmacy, nursing or medical students. A systematic approach was used to retrieve papers and extract relevant data. Results: There were initially identified 435 studies involving social media, healthcare information and medical students subject headings (MeSH terminology. After filtering for free full text articles, and exclusion of not students or social media specific ones, 33 articles were reviewed. The majority of the studies were interventional studies that either assessed the outcomes of online discussion groups or teaching methods through social media. The majority of studies focused on the use of social media as a teaching tool, how students use it and the implications upon their education. The largest number of original papers was published in 2013. Facebook, Podcasts, Multiplayer virtual worlds, Blogs, and Twitter were identified as being used by medical students. Conclusion: Social media is used as a tool of information for students mainly as the means for engaging and communicating with students.

  7. Dynamical Heterogeneity in Granular Fluids and Structural Glasses

    Science.gov (United States)

    Avila, Karina E.

    Our current understanding of the dynamics of supercooled liquids and other similar slowly evolving (glassy) systems is rather limited. One aspect that is particularly poorly understood is the origin and behavior of the strong non trivial fluctuations that appear in the relaxation process toward equilibrium. Glassy systems and granular systems both present regions of particles moving cooperatively and at different rates from other regions. This phenomenon is known as spatially heterogeneous dynamics. A detailed explanation of this phenomenon may lead to a better understanding of the slow relaxation process, and perhaps it could even help to explain the presence of the glass transition. This dissertation concentrates on studying dynamical heterogeneity by analyzing simulation data for models of granular materials and structural glasses. For dissipative granular fluids, the growing behavior of dynamical heterogeneities is studied for different densities and different degrees of inelasticity in the particle collisions. The correlated regions are found to grow rapidly as the system approaches dynamical arrest. Their geometry is conserved even when probing at different cutoff length in the correlation function or when the energy dissipation in the system is increased. For structural glasses, I test a theoretical framework that models dynamical heterogeneity as originated in the presence of Goldstone modes, which emerge from a broken continuous time reparametrization symmetry. This analysis is based on quantifying the size and the spatial correlations of fluctuations in the time variable and of other kinds of fluctuations. The results obtained here agree with the predictions of the hypothesis. In particular, the fluctuations associated to the time reparametrization invariance become stronger for low temperatures, long timescales, and large coarse graining lengths. Overall, this research points to dynamical heterogeneity to be described for granular systems similarly than

  8. Whole-genome sequencing of a malignant granular cell tumor with metabolic response to pazopanib

    Science.gov (United States)

    Wei, Lei; Liu, Song; Conroy, Jeffrey; Wang, Jianmin; Papanicolau-Sengos, Antonios; Glenn, Sean T.; Murakami, Mitsuko; Liu, Lu; Hu, Qiang; Conroy, Jacob; Miles, Kiersten Marie; Nowak, David E.; Liu, Biao; Qin, Maochun; Bshara, Wiam; Omilian, Angela R.; Head, Karen; Bianchi, Michael; Burgher, Blake; Darlak, Christopher; Kane, John; Merzianu, Mihai; Cheney, Richard; Fabiano, Andrew; Salerno, Kilian; Talati, Chetasi; Khushalani, Nikhil I.; Trump, Donald L.; Johnson, Candace S.; Morrison, Carl D.

    2015-01-01

    Granular cell tumors are an uncommon soft tissue neoplasm. Malignant granular cell tumors comprise T transitions, particularly when immediately preceded by a 5′ G. A loss-of-function mutation was detected in a newly recognized tumor suppressor candidate, BRD7. No mutations were found in known targets of pazopanib. However, we identified a receptor tyrosine kinase pathway mutation in GFRA2 that warrants further evaluation. To the best of our knowledge, this is only the second reported case of a malignant granular cell tumor exhibiting a response to pazopanib, and the first whole-genome sequencing of this uncommon tumor type. The findings provide insight into the genetic basis of malignant granular cell tumors and identify potential targets for further investigation. PMID:27148567

  9. Teaching Mediated Public Relations.

    Science.gov (United States)

    Kent, Michael L.

    2001-01-01

    Discusses approaches to teaching a mediated public relations course, emphasizing the World Wide Web. Outlines five course objectives, assignments and activities, evaluation, texts, and lecture topics. Argues that students mastering these course objectives will understand ethical issues relating to media use, using mediated technology in public…

  10. Happy to be teaching?

    NARCIS (Netherlands)

    Ria Vogels

    2009-01-01

    Original title: Gelukkig voor de klas? If we are to believe reports in the media, working as a secondary school teacher is no fun. High pressure of work, low salaries, teaching standards imposed by others and interfering, inadequate school managements all combine to dent people's enthusiasm

  11. The critical current of granular superconductor

    International Nuclear Information System (INIS)

    Ignat'ev, V.K.

    1998-01-01

    A mechanism of hyper vortex pinning in granular superconductors is proposed to describe the field dependence of the critical current density and pinning potential. The results are in a good agreement with the experiment. The model represents the peak effect and the percolation mechanism of conductivity in ceramic superconductors

  12. Tumor de células granulares bifocal em mucosa jugal

    Directory of Open Access Journals (Sweden)

    Victor Yuri Nicolau Ferreira

    Full Text Available O tumor de células granulares é uma lesão incomum que apresenta predileção pela cavidade oral, por apresentar baixa taxa de recidiva, o tratamento de escolha é a excisão cirúrgica simples. O objetivo caracterizar um caso de tumor de células granulares bifocal em mucosa jugal e explanar características clínicas e histopatológicas acerca da lesão. Relata-se o caso de uma paciente de 60 anos apresentando dois pequenos nódulos de superfície lisa em mucosa jugal, consistência fibroelástica e coloração levemente amarelada. Foi realizada a excisão cirúrgica das duas lesões a partir de uma biópsia excisional, onde microscopicamente foi observada uma neoplasia de células granulares arranjadas em ilhas, chegando ao diagnóstico de Tumor de células granulares. O diagnóstico final da lesão foi obtido a partir do exame histopatológico, visto que, a aparência clínica da lesão é inespecífica, sendo de extrema importância a realização da biópsia excisional. A paciente continua em acompanhamento há 6 meses e não demonstra recidiva da lesão.

  13. Universal scaling of permeability through the granular-to-continuum transition

    Science.gov (United States)

    Wadsworth, F. B.; Scheu, B.; Heap, M. J.; Kendrick, J. E.; Vasseur, J.; Lavallée, Y.; Dingwell, D. B.

    2015-12-01

    Magmas fragment forming a transiently granular material, which can weld back to a fluid-continuum. This process results in dramatic changes in the gas-volume fraction of the material, which impacts the gas permeability. We collate published data for the gas-volume fraction and permeability of volcanic and synthetic materials which have undergone this process to different amounts and note that in all cases there exists a discontinuity in the relationship between these two properties. By discriminating data for which good microstructural information are provided, we use simple scaling arguments to collapse the data in both the still-granular, high gas-volume fraction regime and the fluid-continuum low gas-volume fraction regime such that a universal description can be achieved. We use this to argue for the microstructural meaning of the well-described discontinuity between gas-permeability and gas-volume fraction and to infer the controls on the position of this transition between dominantly granular and dominantly fluid-continuum material descriptions. As a specific application, we consider the transiently granular magma transported through and deposited in fractures in more-coherent magmas, thought to be a primary degassing pathway in high viscosity systems. We propose that our scaling coupled with constitutive laws for densification can provide insights into the longevity of such degassing channels, informing sub-surface pressure modelling at such volcanoes.

  14. Teaching International Business via Social Media Projects

    Science.gov (United States)

    Alon, Ilan; Herath, Ruwanthi Kumari

    2014-01-01

    The purpose of this study is to evaluate the outcomes of an experiential learning technique coupled with social media in an international marketing course. It was conducted among 155 students placed in groups that were assigned to develop a YouTube video for use as a country branding marketing tool. Measured evaluations of the students'…

  15. Characterization of granular collapse onto hard substrates by acoustic emissions

    Science.gov (United States)

    Farin, Maxime; Mangeney, Anne; Toussaint, Renaud; De Rosny, Julien

    2013-04-01

    Brittle deformation in granular porous media can generate gravitational instabilities such as debris flows and rock avalanches. These phenomena constitute a major natural hazard for the population in mountainous, volcanic and coastal areas but their direct observation on the field is very dangerous. Recent studies showed that gravitational instabilities can be detected and characterized (volume, duration,...) thanks to the seismic signal they generate. In an avalanche, individual block bouncing and rolling on the ground are expected to generated signals of higher frequencies than the main flow spreading. The identification of the time/frequency signature of individual blocks in the recorded signal remains however difficult. Laboratory experiments were conducted to investigate the acoustic signature of diverse simple sources corresponding to grains falling over thin plates of plexiglas and rock blocks. The elastic energy emitted by a single bouncing steel bead into the support was first quantitatively estimated and compared to the potential energy of fall and to the potential energy change during the shock. Next, we consider the collapse of granular columns made of steel spherical beads onto hard substrates. Initially, these columns were held by a magnetic field allowing to suppress suddenly the cohesion between the beads, and thus to minimize friction effects that would arise from side walls. We varied systematically the column volume, the column aspect ratio (height over length) and the grain size. This is shown to affect the signal envelope and frequency content. In the experiments, two types of acoustic sensors were used to record the signals in a wide frequency range: accelerometers (1 Hz to 56 kHz) and piezoelectric sensors (100 kHz to 1 MHz). The experiments were also monitored optically using fast cameras. We developed a technique to use quantitatively both types of sensors to evaluate the elastic energy emitted by the sources. Eventually, we looked at what

  16. Resistance capability of microaerobic granular sludge for ...

    African Journals Online (AJOL)

    enoh

    2012-02-08

    Feb 8, 2012 ... The resistance capability to pH shock of microaerobic granular sludge for pentachlorophenol (PCP) ... process with chlorine gas in pulp and paper, leather and spinning ... nitrifying bacteria in the aerobic zone, and then trans-.

  17. Problematizing Videogames: Teaching Students to Be Critical Players

    Science.gov (United States)

    Love, Mark

    2017-01-01

    This contribution aims to familiarize educators with the unique ways in which videogames convey meaning as a media form and to provide an instrument, based on videogame theory, that educators can easily employ in intermediate and advanced English as a Foreign Language (EFL) classrooms to teach critical media literacy. In order to equip teachers…

  18. Grammatical terminology for the teaching of African languages at ...

    African Journals Online (AJOL)

    The article addresses the question of the elaboration and modernisation of African languages to enable them to be used as language media for the teaching of African languages, particularly grammar. Whereas all institutions at tertiary level of education have undergone a paradigm shift from teaching African languages in ...

  19. Removal of organochlorine pesticides from water using virgin and regenerated granular activated carbon

    Directory of Open Access Journals (Sweden)

    MIRJANA B. NINKOVIĆ

    2010-04-01

    Full Text Available Public water systems use granular activated carbon in order to eliminate pesticides. After saturation, the used activated carbon is regenerated and reused in order to reduce the costs of water production and minimize waste. In this study, the adsorption of 10 different chlorinated pesticides from water using columns packed with commercial virgin and regenerated granular activated carbon was simulated in order to compare their adsorption capacities for different chlorinated pesticides. The breakthrough curves showed that chlorinated pesticides from the group of hexachlorocyclohexane (HCH were poorly adsorbed, followed by cyclodiens as averagely adsorbed and the derivatives of halogenated aromatic hydrocarbons (DDT as strongly adsorbed. However, the adsorption capacity of regenerated granular activated carbon was considerably lower for tested pesticides compared to the virgin granular carbon. In addition, rinsing of the pesticides after the saturation point is a far more efficient process on regenerated carbon.

  20. Exploration of Teaching Preferences of Instructors' Use of Social Media

    Science.gov (United States)

    Kilis, Selcan; Gülbahar, Yasemin; Rapp, Christian

    2016-01-01

    With the excessive use of social media in the 21st century, attempts to integrate social media within higher education have also increased. In this area, research has been particularly focused on the aspects of students, rather than the instructors. This study puts the emphasis on the instructors with the aim to explore their use of social media…