WorldWideScience

Sample records for vti media poroelasticity

  1. PROPAGATION OF CYLINDRICAL WAVES IN POROELASTIC MEDIA

    Directory of Open Access Journals (Sweden)

    Vorona Yu.V.

    2014-12-01

    Full Text Available The paper investigates the harmonic axisymmetric wave propagation in poroelastic media. The computational formulas for the study of displacements and stresses that occur during vibrations in a wide frequency range are proposed.

  2. An acoustic eikonal equation for attenuating VTI media

    KAUST Repository

    Hao, Qi

    2016-09-06

    We present an acoustic eikonal equation governing the complex-valued travel time of P-waves in attenuating, transversely isotropic media with a vertical symmetry axis (VTI). This equation is based on the assumption that the Pwave complex-valued travel time is independent of the Swave velocity parameter v in Thomsen\\'s notation and the attenuation coefficient A in the Thomsen-type notation for attenuating VTI media. We combine perturbation theory and Shanks transform to develop practical approximations to the attenuating acoustic eikonal equation, capable of admitting analytical description of the attenuation in homogeneous media. For a horizontal, attenuating VTI layer, we also derive non-hyperbolic approximations for the real and imaginary parts of the complex-valued reflection travel time.

  3. Separate P‐ and SV‐wave equations for VTI media

    KAUST Repository

    Pestana, Reynam C.

    2011-01-01

    In isotropic media we use the scalar acoustic wave equation to perform reverse time migration RTM of the recorded pressure wavefleld data. In anisotropic media P- and SV-waves are coupled and the elastic wave equation should be used for RTM. However, an acoustic anisotropic wave equation is often used instead. This results in significant shear wave energy in both modeling and RTM. To avoid this undesired SV-wave energy, we propose a different approach to separate P- and SV-wave components for vertical transversely isotropic VTI media. We derive independent pseudo-differential wave equations for each mode. The derived equations for P- and SV-waves are stable and reduce to the isotropic case. The equations presented here can be effectively used to model and migrate seismic data in VTI media where ε - δ is small. The SV-wave equation we develop is now well-posed and triplications in the SV wavefront are removed resulting in stable wave propagation. We show modeling and RTM results using the derived pure P-wave mode in complex VTI media and use the rapid expansion method REM to propagate the waveflelds in time. © 2011 Society of Exploration Geophysicists.

  4. Anisotropic parameter inversion in VTI media using diffraction data

    KAUST Repository

    Waheed, Umair bin

    2013-09-22

    Diffracted waves contain useful information regarding the subsurface geometry and velocity. They are particularly valuable for anisotropic media as they inherently possess a wide range of dips necessary to resolve angular dependence of velocity. Using this property of diffraction data to our vantage, we develop an algorithm to invert for effective η model, assuming no prior knowledge of it. The obtained effective η model is then converted to interval η model using Dix-type inversion formula. The effectiveness of this approach is tested on the VTI Marmousi model, which yields good structural match even for a highly complex media such as the Marmousi model.

  5. Waveform inversion for acoustic VTI media in frequency domain

    KAUST Repository

    Wu, Zedong

    2016-09-06

    Reflected waveform inversion (RWI) provides a method to reduce the nonlinearity of the standard full waveform inversion (FWI) by inverting for the background model using a single scattered wavefield from an inverted perturbation. However, current RWI methods are mostly based on isotropic media assumption. We extend the idea of the combining inversion for the background model and perturbations to address transversely isotropic with a vertical axis of symmetry (VTI) media taking into consideration of the optimal parameter sensitivity information. As a result, we apply Born modeling corresponding to perturbations in only for the variable e to derive the relative reflected waveform inversion formulation. To reduce the number of parameters, we assume the background part of η = ε and work with a single variable to describe the anisotropic part of the wave propagation. Thus, the optimization variables are the horizontal velocity v, η = ε and the e perturbation. Application to the anisotropic version of Marmousi model with a single frequency of 2.5 Hz shows that this method can converge to the accurate result starting from a linearly increasing isotropic initial velocity. Application to a real dataset demonstrates the versatility of the approach.

  6. Analysis of RTM extended images for VTI media

    KAUST Repository

    Li, Vladimir

    2016-04-28

    Extended images obtained from reverse time migration (RTM) contain information about the accuracy of the velocity field and subsurface illumination at different incidence angles. Here, we evaluate the influence of errors in the anisotropy parameters on the shape of the residual moveout (RMO) in P-wave RTM extended images for VTI (transversely isotropic with a vertical symmetry axis) media. Using the actual spatial distribution of the zero-dip NMO velocity (Vnmo), which could be approximately estimated by conventional techniques, we analyze the extended images obtained with distorted fields of the parameters η and δ. Differential semblance optimization (DSO) and stack-power estimates are employed to study the sensitivity of focusing to the anisotropy parameters. We also build angle gathers to facilitate interpretation of the shape of RMO in the extended images. The results show that the signature of η is dip-dependent, whereas errors in δ cause defocusing only if that parameter is laterally varying. Hence, earlier results regarding the influence of η and δ on reflection moveout and migration velocity analysis remain generally valid in the extended image space for complex media. The dependence of RMO on errors in the anisotropy parameters provides essential insights for anisotropic wavefield tomography using extended images.

  7. Analysis of RTM extended images for VTI media

    KAUST Repository

    Li, Vladimir

    2015-08-19

    Extended images obtained from reverse-time migration (RTM) contain information about the accuracy of the velocity field and subsurface illumination at different incidence angles. Here, we evaluate the influence of errors in the anisotropy parameters on the shape of the residual moveout (RMO) in P-wave RTM extended images for VTI (transversely isotropic with a vertical symmetry axis) media. Considering the actual spatial distribution of the zero-dip NMO velocity (Vnmo), which could be approximately estimated by conventional techniques, we analyze the extended images obtained with distorted fields of the parameters η and δ. Differential semblance optimization (DSO) and stack-power estimates are employed to study the sensitivity of focusing to the anisotropy parameters. The results show that the signature of η is dip-dependent, whereas errors in δ cause defocusing only if that parameter is laterally varying. Hence, earlier results regarding the influence of η and δ on reflection moveout and migration velocity analysis remain generally valid in the extended image space for complex media. The dependence of RMO on errors in the anisotropy parameters provides essential insights for anisotropic wavefield tomography using extended images.

  8. Frequency Domain Multi-parameter Full Waveform Inversion for Acoustic VTI Media

    KAUST Repository

    Djebbi, Ramzi

    2017-05-26

    Multi-parameter full waveform inversion (FWI) for transversely isotropic (TI) media with vertical axis of symmetry (VTI) suffers from the trade-off between the parameters. The trade-off results in the leakage of one parameter\\'s update into the other during the inversion. It affects the accuracy and convergence of the inversion. The sensitivity analyses suggested a parameterisation using the horizontal velocity vh, epsilon and eta to reduce the trade-off for surface recorded seismic data.We test the (vh, epsilon, eta) parameterisation for acoustic VTI media using a scattering integral (SI) based inversion. The data is modeled in frequency domain and the model is updated using a preconditioned conjugate gradient method. We applied the method to the VTI Marmousi II model and in the inversion, we keep eta parameter fixed as the background initial model and we invert simultaneously for both vh and epsilon. The results show the suitability of the parameterisation for multi-parameter VTI acoustic inversion as well as the accuracy of the inversion approach.

  9. Features of deformation of poroelastic media with low structural strength

    Science.gov (United States)

    Goldstein, Robert; Gordeev, Yurii; Kornev, Konstantin

    Many natural and technological processes are associated with deformation and fracture of saturated or being saturated poroelastic media. Among such processes one can mention fluid soaking through a dam, fluid inflow to the cracks of hydraulic fracture, polishing using porous materials and special fluids, flow in catalytic pellets. All these processes are accompanied by deformation and fracture of a matrix with fluid flow. The effects at the interface porous body-fluid are essential for the processes. The specific features of deformation of poroelastic media with low structural strength are considered in this paper. The compressibility of the matrix skeleton is larger as compared to the compressibility of the saturating fluid in such media. It is shown that the oozing of the fluid at the surface of the poroelastic medium occurs in the consolidated flow regime under the action of `fluid piston' like loads if the structural strength of the medium is low. This result is obtained for both plane (deformation of a layer or halfinfinite medium) and centrally symmetric (deformation of a sphere) problems.

  10. Elastic FWI for VTI media: A synthetic parameterization study

    KAUST Repository

    Kamath, Nishant

    2016-09-06

    A major challenge for multiparameter full-waveform inversion (FWI) is the inherent trade-offs (or cross-talk) between model parameters. Here, we perform FWI of multicomponent data generated for a synthetic VTI (transversely isotropic with a vertical symmetry axis) model based on a geologic section of the Valhall field. A horizontal displacement source, which excites intensive shear waves in the conventional offset range, helps provide more accurate updates to the SV-wave vertical velocity. We test three model parameterizations, which exhibit different radiation patterns and, therefore, create different parameter trade-offs. The results show that the choice of parameterization for FWI depends on the availability of long-offset data, the quality of the initial model for the anisotropy coefficients, and the parameter that needs to be resolved with the highest accuracy.

  11. The stability problem of reverse time migration for viscoacoustic VTI media

    Science.gov (United States)

    Sun, Xiao-Dong; Ge, Zhong-Hui; Li, Zhen-Chun; Hong, Ying

    2016-12-01

    In real strata anisotropy and viscosity extensively exists. They degraded waveforms in amplitude, resulting in which reducing of image resolution. To obtain high-precision imaging of deep reservoirs, we extended the separated viscous and anisotropic reverse time migration (RTM) to a stable viscoacoustic anisotropic RTM for vertical transverse isotropic (VTI) media, based on single generalized standard and linear solid (GSLS) media theory.. We used a pseudo-spectral method to develop the numerical simulation. By introducing a regularization operator to eliminate the high-frequency instability problem, we built a stable inverse propagator and achieved viscoacoustic VTI media RTM. High-resolution imaging results were obtained after correcting for the effects of anisotropy and viscosity. Synthetic tests verify the validity and accuracy of algorithm.

  12. Rapid expansion and pseudo spectral implementation for reverse time migration in VTI media

    KAUST Repository

    Pestana, Reynam C

    2012-04-24

    In isotropic media, we use the scalar acoustic wave equation to perform reverse time migration (RTM) of the recorded pressure wavefield data. In anisotropic media, P- and SV-waves are coupled, and the elastic wave equation should be used for RTM. For computational efficiency, a pseudo-acoustic wave equation is often used. This may be solved using a coupled system of second-order partial differential equations. We solve these using a pseudo spectral method and the rapid expansion method (REM) for the explicit time marching. This method generates a degenerate SV-wave in addition to the P-wave arrivals of interest. To avoid this problem, the elastic wave equation for vertical transversely isotropic (VTI) media can be split into separate wave equations for P- and SV-waves. These separate wave equations are stable, and they can be effectively used to model and migrate seismic data in VTI media where |ε- δ| is small. The artifact for the SV-wave has also been removed. The independent pseudo-differential wave equations can be solved one for each mode using the pseudo spectral method for the spatial derivatives and the REM for the explicit time advance of the wavefield. We show numerically stable and high-resolution modeling and RTM results for the pure P-wave mode in VTI media. © 2012 Sinopec Geophysical Research Institute.

  13. Elastic full-waveform inversion of transmission data in 2D VTI media

    KAUST Repository

    Kamath, Nishant

    2014-08-05

    Full-waveform inversion (FWI) has been implemented mostly for isotropic media, with extensions to anisotropic models typically limited to acoustic approximations. Here, we develop elastic FWI for transmitted waves in 2D heterogeneous VTI (transversely isotropic with a vertical symmetry axis) media. The model is parameterized in terms of the P- and S-wave vertical velocities and the P-wave normal-moveout and horizontal velocities. To test the FWI algorithm, we introduce Gaussian anomalies in the Thomsen parameters of a homogeneous VTI medium and perform FWI of transmission data for different configurations of the source and receiver arrays. The inversion results strongly depend on the acquisition geometry and the aperture because of the parameter trade-offs. In contrast to acoustic FWI, the elastic inversion helps constrain the S-wave vertical velocity, which for our model is decoupled from the other parameters.

  14. Full-waveform inversion with reflected waves for 2D VTI media

    KAUST Repository

    Pattnaik, Sonali

    2016-09-06

    Full-waveform inversion in anisotropic media using reflected waves suffers from the strong non-linearity of the objective function and trade-offs between model parameters. Estimating long-wavelength model components by fixing parameter perturbations, referred to as reflection-waveform inversion (RWI), can mitigate nonlinearity-related inversion issues. Here, we extend RWI to acoustic VTI (transversely isotropic with a vertical symmetry axis) media. To minimize trade-offs between the model parameters, we employ a new hierarchical two-stage approach that operates with the P-wave normal-moveout velocity and anisotropy coefficents ζ and η. First, is estimated using a fixed perturbation in ζ, and then we invert for η by fixing the updated perturbation in . The proposed 2D algorithm is tested on a horizontally layered VTI model.

  15. Multi-stage full waveform inversion strategy for 2D elastic VTI media

    KAUST Repository

    Oh, Juwon

    2015-08-19

    One of the most important issues in the multi-parametric full waveform inversion (FWI) is to find an optimal parameterization, which helps us recover the subsurface anisotropic parameters as well as seismic velocities, with minimal tradeoff. As a result, we analyze three different parameterizations for elastic VTI media in terms of the influence of the S-waves on the gradient direction for c13, the spatial coverage of gradient direction and the degree of trade-offs between the parameters. Based on the dependency results, we design a multi-stage elastic VTI FWI strategy to enhance both the spatial coverage of the FWI and the robustness to the trade-offs among the parameters as well as FWI for the c13 structure.

  16. Azimuth and angle gathers from wave equation imaging in VTI media

    KAUST Repository

    Alkhalifah, Tariq Ali

    2009-01-01

    Angles in common-image angle domain gathers refer to the scattering angle at the reflector and provide a natural access to analyzing migration velocities and amplitudes. In the case of anisotropic media, the importance of angle gathers is enhanced by the need to properly estimate multiple anisotropic parameters for a proper representation of the medium. We extract angle gathers for each downward-continuation step from converting offset-space-frequency planes into angle-space planes simultaneously with applying the imaging condition in a transversely isotropic (VTI) medium. The analytic equations, though cumbersome, are exact within the framework of the acoustic approximation. They are also easily programmable and show that angle gather mapping in the case anisotropic media differs from its isotropic counterpart, difference depending mainly on the strength of anisotropy.

  17. Coupled poroelastic waves and electromagnetic fields in layered media : Theory, Modeling, and Interferometric Synthesis

    NARCIS (Netherlands)

    Grobbe, N.

    2016-01-01

    In this thesis, I study coupled poroelastic waves and electromagnetic fields in layered media. The focus is two-fold:
    1. Increase the theoretical and physical understanding of the seismo-electromagnetic phenomenon by analytically-based numerical modeling.
    2. Investigate the potential of

  18. Influence of Poroelasticity on the 3D Seismic Response of Complex Geological Media

    Directory of Open Access Journals (Sweden)

    Wuttke Frank

    2017-06-01

    Full Text Available Elastic wave propagation in 3D poroelastic geological media with localized heterogeneities, such as an elastic inclusion and a canyon is investigated to visualize the modification of local site responses under consideration of water saturated geomaterial. The extended computational environment herein developed is a direct Boundary Integral Equation Method (BIEM, based on the frequency-dependent fundamental solution of the governing equation in poro-visco elastodynamics. Bardet’s model is introduced in the analysis as the computationally efficient viscoelastic isomorphism to Biot’s equations of dynamic poroelasticity, thus replacing the two-phase material by a complex valued single-phase one. The potential of Bardet’s analogue is illustrated for low frequency vibrations and all simulation results demonstrate the dependency of wave field developed along the free surface on the properties of the soil material.

  19. Influence of Poroelasticity on the 3D Seismic Response of Complex Geological Media

    Science.gov (United States)

    Wuttke, Frank; Dineva, Petia; Fontara, Ioanna-Kleoniki

    2017-06-01

    Elastic wave propagation in 3D poroelastic geological media with localized heterogeneities, such as an elastic inclusion and a canyon is investigated to visualize the modification of local site responses under consideration of water saturated geomaterial. The extended computational environment herein developed is a direct Boundary Integral Equation Method (BIEM), based on the frequency-dependent fundamental solution of the governing equation in poro-visco elastodynamics. Bardet's model is introduced in the analysis as the computationally efficient viscoelastic isomorphism to Biot's equations of dynamic poroelasticity, thus replacing the two-phase material by a complex valued single-phase one. The potential of Bardet's analogue is illustrated for low frequency vibrations and all simulation results demonstrate the dependency of wave field developed along the free surface on the properties of the soil material.

  20. Skeletonized Wave Equation Inversion in VTI Media without too much Math

    KAUST Repository

    Feng, Shihang

    2017-05-17

    We present a tutorial for skeletonized inversion of pseudo-acoustic anisotropic VTI data. We first invert for the anisotropic models using wave equation traveltime inversion. Here, the skeletonized data are the traveltimes of transmitted and/or reflected arrivals that lead to simpler misfit functions and more robust convergence compared to full waveform inversion. This provides a good starting model for waveform inversion. The effectiveness of this procedure is illustrated with synthetic data examples and a marine data set recorded in the Gulf of Mexico.

  1. Sensitivity analysis for elastic full-waveform inversion in VTI media

    KAUST Repository

    Kamath, Nishant

    2014-08-05

    Multiparameter full-waveform inversion (FWI) is generally nonunique, and the results are strongly influenced by the geometry of the experiment and the type of recorded data. Studying the sensitivity of different subsets of data to the model parameters may help in choosing an optimal acquisition design, inversion workflow, and parameterization. Here, we derive the Fréchet kernel for FWI of multicomponent data from a 2D VTI (tranversely isotropic with a vertical symmetry axis) medium. The kernel is obtained by linearizing the elastic wave equation using the Born approximation and employing the asymptotic Green\\'s function. The amplitude of the kernel (‘radiation pattern’) yields the angle-dependent energy scattered by a perturbation in a certain model parameter. The perturbations are described in terms of the P- and S-wave vertical velocities and the P-wave normal-moveout and horizontal velocities. The background medium is assumed to be homogeneous and isotropic, which allows us to obtain simple expressions for the radiation patterns corresonding to all four velocities. These patterns help explain the FWI results for multicomponent transmission data generated for Gaussian anomalies in the Thomsen parameters inserted into a homogeneous VTI medium.

  2. Analysis of flexural wave propagation in poroelastic composite ...

    African Journals Online (AJOL)

    Wave propagation in an infinitely long poroelastic composite hollow cylinder in is examined by employing Biot's theory of wave propagation in poroelastic media. A poroelastic composite hollow cylinder consists of two concentric poroelastic cylindrical layers both of which are made of different poroelastic materials with each ...

  3. Longitudinal shear vibrations of composite poroelastic cylinders ...

    African Journals Online (AJOL)

    Employing Biot's theory of wave propagation in liquid saturated porous media, longitudinal shear vibrations of composite poroelastic cylinders of infinite extent are investigated. The composite poroelastic cylinder is made of two different poroelastic materials. The dilatations of liquid and solid media are zero, hence liquid ...

  4. Contact mechanics for poroelastic, fluid-filled media, with application to cartilage

    Science.gov (United States)

    Persson, B. N. J.

    2016-12-01

    I study a simple contact mechanics model for a poroelastic, fluid-filled solid squeezed against a rigid, randomly rough substrate. I study how the fluid is squeezed out from the interface, and how the area of contact, and the average interfacial separation, change with time. I present numerical results relevant for a human cartilage. I show that for a fluid filled poroelastic solid the probability of cavitation (and the related wear as the cavities implode), and dynamical scraping (defined below and in Hutt and Persson, J. Chem. Phys. 144, 124903 (2016)), may be suppressed by fluid flow from the poroelastic solid into the (roughness induced) interfacial gap between the solids.

  5. Contact mechanics for poroelastic, fluid-filled media, with application to cartilage.

    Science.gov (United States)

    Persson, B N J

    2016-12-21

    I study a simple contact mechanics model for a poroelastic, fluid-filled solid squeezed against a rigid, randomly rough substrate. I study how the fluid is squeezed out from the interface, and how the area of contact, and the average interfacial separation, change with time. I present numerical results relevant for a human cartilage. I show that for a fluid filled poroelastic solid the probability of cavitation (and the related wear as the cavities implode), and dynamical scraping (defined below and in Hutt and Persson, J. Chem. Phys. 144, 124903 (2016)), may be suppressed by fluid flow from the poroelastic solid into the (roughness induced) interfacial gap between the solids.

  6. An Approximate Method for the Acoustic Attenuating VTI Eikonal Equation

    KAUST Repository

    Hao, Q.

    2017-05-26

    We present an approximate method to solve the acoustic eikonal equation for attenuating transversely isotropic media with a vertical symmetry axis (VTI). A perturbation method is used to derive the perturbation formula for complex-valued traveltimes. The application of Shanks transform further enhances the accuracy of approximation. We derive both analytical and numerical solutions to the acoustic eikonal equation. The analytic solution is valid for homogeneous VTI media with moderate anellipticity and strong attenuation and attenuation-anisotropy. The numerical solution is applicable for inhomogeneous attenuating VTI media.

  7. Analysis of the multi-component pseudo-pure-mode qP-wave inversion in vertical transverse isotropic (VTI) media

    KAUST Repository

    Djebbi, Ramzi

    2014-08-05

    Multi-parameter inversion in anisotropic media suffers from the inherent trade-off between the anisotropic parameters, even under the acoustic assumption. Multi-component data, often acquired nowadays in ocean bottom acquisition and land data, provide additional information capable of resolving anisotropic parameters under the acoustic approximation assumption. Based on Born scattering approximation, we develop formulas capable of characterizing the radiation patterns for the acoustic pseudo-pure mode P-waves. Though commonly reserved for the elastic fields, we use displacement fields to constrain the acoustic vertical transverse isotropic (VTI) representation of the medium. Using the asymptotic Green\\'s functions and a horizontal reflector we derive the radiation patterns for perturbations in the anisotropic media. The radiation pattern for the anellipticity parameter η is identically zero for the horizontal displacement. This allows us to dedicate this component to invert for velocity and δ. Computing the traveltime sensitivity kernels based on the unwrapped phase confirms the radiation patterns observations, and provide the model wavenumber behavior of the update.

  8. AVO forward modeling for VTI coal

    Energy Technology Data Exchange (ETDEWEB)

    Chen, T.; Cui, R.; Liu, E. [China University of Mining and Technology, Xuzhou (China). School of Resource and Earth Science

    2009-04-15

    The article discusses the possibility of prospecting primary coal, tectonic coal, soft coal and vertical transverse-isotropic (VTI) coal by P- wave amplitude variation with offset (AVO) forward modeling. For thick coal bed, the P-wave AVO curves of primary coal, tectonic coal and soft coal were achieved by the Zoeppritz equation. For a thick VTI coal bed, its stiffness matrix was first calculated by effective media's theory; then the P-wave AVO curve of this coal was calculated by the propagation matrix method which is based on anisotropy theory. In this way the synthetic seismogram was attained by combining the seismic wavelet with AVO curves. At the same time, thin coal seams of AVO curves and a synthetic seismogram were simulated. It is shown that the coal roof's P-wave AVO of thick coal has the AVO character of class IV and the AVO gradient and intercept of the coal beds diverge from each other. For thin coal seams, the reflection waves are composite waves. In this case, the primary coal and tectonic coal's reflection amplitude is small and its AVO with obvious class IV, the VTI coal and soft coal's reflection amplitude is larger, and its AVO curves fluctuate acutely. In summary, the AVO technique could be used to identify primary coal, tectonic coal, soft coal and VTI coal. 12 refs., 4 figs., 2 tabs.

  9. Inversion gradients for acoustic VTI wavefield tomography

    KAUST Repository

    Li, Vladimir

    2017-03-21

    Wavefield tomography can handle complex subsurface geology better than ray-based techniques and, ultimately, provide a higher resolution. Here, we implement forward and adjoint wavefield extrapolation for VTI (transversely isotropic with a vertical symmetry axis) media using a generalized pseudospectral operator based on a separable approximation for the P-wave dispersion relation. This operator is employed to derive the gradients of the differential semblance optimization (DSO) and modified image-power objective functions. We also obtain the gradient expressions for a data-domain objective function that can more easily incorporate borehole information necessary for stable VTI velocity analysis. These gradients are similar to the ones obtained with a space-time finite-difference (FD) scheme for a system of coupled wave equations but the pseudospectral method is not hampered by the imprint of the shear-wave artifact. Numerical examples also show the potential advantages of the modified image-power objective function in estimating the anellipticity parameter η.

  10. Analysis of dispersion and attenuation of surface waves in poroelastic media in the exploration-seismic frequency band

    Science.gov (United States)

    Zhang, Y.; Xu, Y.; Xia, J.

    2011-01-01

    We analyse dispersion and attenuation of surface waves at free surfaces of possible vacuum/poroelastic media: permeable-'open pore', impermeable-'closed pore' and partially permeable boundaries, which have not been previously reported in detail by researchers, under different surface-permeable, viscous-damping, elastic and fluid-flowing conditions. Our discussion is focused on their characteristics in the exploration-seismic frequency band (a few through 200 Hz) for near-surface applications. We find two surface-wave modes exist, R1 waves for all conditions, and R2 waves for closed-pore and partially permeable conditions. For R1 waves, velocities disperse most under partially permeable conditions and least under the open-pore condition. High-coupling damping coefficients move the main dispersion frequency range to high frequencies. There is an f1 frequency dependence as a constant-Q model for attenuation at high frequencies. R1 waves for the open pore are most sensitive to elastic modulus variation, but least sensitive to tortuosities variation. R1 waves for partially permeable surface radiate as non-physical waves (Im(k) attenuation are diffusive of f1/2 frequency dependence, as P2 waves. It is found that for partially permeable surfaces, the attenuation displays -f1 frequency dependence as frequency increasing. High surface permeability, low-coupling damping coefficients, low Poisson's ratios, and low tortuosities increase the slope of the -f1 dependence. When the attenuation coefficients reach 0, R2 waves for partially permeable surface begin to radiate as non-physical waves. ?? 2011 The Authors Geophysical Journal International ?? 2011 RAS.

  11. Fully Coupled Nonlinear Fluid Flow and Poroelasticity in Arbitrarily Fractured Porous Media: A Hybrid-Dimensional Computational Model

    Science.gov (United States)

    Jin, L.; Zoback, M. D.

    2017-10-01

    We formulate the problem of fully coupled transient fluid flow and quasi-static poroelasticity in arbitrarily fractured, deformable porous media saturated with a single-phase compressible fluid. The fractures we consider are hydraulically highly conductive, allowing discontinuous fluid flux across them; mechanically, they act as finite-thickness shear deformation zones prior to failure (i.e., nonslipping and nonpropagating), leading to "apparent discontinuity" in strain and stress across them. Local nonlinearity arising from pressure-dependent permeability of fractures is also included. Taking advantage of typically high aspect ratio of a fracture, we do not resolve transversal variations and instead assume uniform flow velocity and simple shear strain within each fracture, rendering the coupled problem numerically more tractable. Fractures are discretized as lower dimensional zero-thickness elements tangentially conforming to unstructured matrix elements. A hybrid-dimensional, equal-low-order, two-field mixed finite element method is developed, which is free from stability issues for a drained coupled system. The fully implicit backward Euler scheme is employed for advancing the fully coupled solution in time, and the Newton-Raphson scheme is implemented for linearization. We show that the fully discretized system retains a canonical form of a fracture-free poromechanical problem; the effect of fractures is translated to the modification of some existing terms as well as the addition of several terms to the capacity, conductivity, and stiffness matrices therefore allowing the development of independent subroutines for treating fractures within a standard computational framework. Our computational model provides more realistic inputs for some fracture-dominated poromechanical problems like fluid-induced seismicity.

  12. Multiscale model reduction for shale gas transport in poroelastic fractured media

    Science.gov (United States)

    Akkutlu, I. Yucel; Efendiev, Yalchin; Vasilyeva, Maria; Wang, Yuhe

    2018-01-01

    Inherently coupled flow and geomechanics processes in fractured shale media have implications for shale gas production. The system involves highly complex geo-textures comprised of a heterogeneous anisotropic fracture network spatially embedded in an ultra-tight matrix. In addition, nonlinearities due to viscous flow, diffusion, and desorption in the matrix and high velocity gas flow in the fractures complicates the transport. In this paper, we develop a multiscale model reduction approach to couple gas flow and geomechanics in fractured shale media. A Discrete Fracture Model (DFM) is used to treat the complex network of fractures on a fine grid. The coupled flow and geomechanics equations are solved using a fixed stress-splitting scheme by solving the pressure equation using a continuous Galerkin method and the displacement equation using an interior penalty discontinuous Galerkin method. We develop a coarse grid approximation and coupling using the Generalized Multiscale Finite Element Method (GMsFEM). GMsFEM constructs the multiscale basis functions in a systematic way to capture the fracture networks and their interactions with the shale matrix. Numerical results and an error analysis is provided showing that the proposed approach accurately captures the coupled process using a few multiscale basis functions, i.e. a small fraction of the degrees of freedom of the fine-scale problem.

  13. Recovery of Biot's transition frequency of air-saturated poroelastic media using vibroacoustic spectroscopy

    Science.gov (United States)

    Ogam, Erick; Fellah, Z. E. A.

    2014-08-01

    The transition frequency marks the passage from low-frequency viscosity dominated flow to high-frequency inertia dominated one in porous media. It was one of the principal characteristics predicted by Biot's theory. The transition frequency has been a theoretical concept for which only theoretical expressions have been developed in recent years. A vibroacoustic spectroscopy experimental method to recover the characteristic frequency (fC) and for gaining insight into the frequency response of fluid-saturated porous materials has been developed. Long thin air-saturated porous rods solicited mechanically are employed for the experiment. Changes in the fluid flow profile with excitation frequency results in relative motion between the skeleton and the saturating-fluid. This enhances the frictional viscous forces, which, in turn, increases damping of the skeletal motion. These transitions are signaled by observable cues in the acquired laser-vibrometry spectrum of the rods' longitudinal vibration mode patterns. The resonance peaks exhibit sudden attenuation (increase in damping) and are interrupted at the transition frequencies evoking a change of propagation medium. These patterns are compared with those of two plains, single phase material (viscoelastic) rods whose modes stand out as regularly spaced moderately damped peaks.

  14. Gradient computation for VTI acoustic wavefield tomography

    KAUST Repository

    Li, Vladimir

    2016-09-06

    Wavefield tomography can handle complex subsurface geology better than ray-based techniques and, ultimately, provide a higher resolution. Here, we implement forward and adjoint wavefield extrapolation for VTI (transversely isotropic with a vertical symmetry axis) media using a pseudospectral operator that employes a separable approximation of the P-wave dispersion relation. This operator is employed to derive the gradients of the differential semblance optimization (DSO) and modified stack-power objective functions. We also obtain the gradient expressions for the data-domain objective function, which can incorporate borehole information necessary for stable VTI velocity analysis. These gradients are compared to the ones obtained with a space-time finite-difference (FD) scheme for a system of coupled wave equations. Whereas the kernels computed with the two wave-equation operators are similar, the pseudospectral method is not hampered by the imprint of the shear-wave artifact. Numerical examples also show that the modified stack-power objective function produces cleaner gradients than the more conventional DSO operator.

  15. Torsional vibrations of infinite composite poroelastic cylinders

    African Journals Online (AJOL)

    user

    Abstract. A study of torsional vibrations of an infinite composite poroelastic circular solid cylinder made of two different materials is made. The frequency equation of such torsional vibrations is obtained following analytical model based on Biot's theory of wave propagation in liquid saturated porous media. Each dilatation of ...

  16. Topology optimization of fluid-structure-interaction problems in poroelasticity

    DEFF Research Database (Denmark)

    Andreasen, Casper Schousboe; Sigmund, Ole

    2013-01-01

    This paper presents a method for applying topology optimization to fluid-structure interaction problems in saturated poroelastic media. The method relies on a multiple-scale method applied to periodic media. The resulting model couples the Stokes flow in the pores of the structure with the deform......This paper presents a method for applying topology optimization to fluid-structure interaction problems in saturated poroelastic media. The method relies on a multiple-scale method applied to periodic media. The resulting model couples the Stokes flow in the pores of the structure...... with the deformation of the elastic skeleton through a macroscopic Darcy-type flow law. The method allows to impose pressure loads for static problems through a one way coupling, while transient problems are fully coupled modeling the interaction between fluid and solid. The material distribution is determined...

  17. The SNARE protein vti1a functions in dense-core vesicle biogenesis

    DEFF Research Database (Denmark)

    Walter, Alexander M; Kurps, Julia; de Wit, Heidi

    2014-01-01

    The SNARE protein vti1a is proposed to drive fusion of intracellular organelles, but recent data also implicated vti1a in exocytosis. Here we show that vti1a is absent from mature secretory vesicles in adrenal chromaffin cells, but localizes to a compartment near the trans-Golgi network, partially...... overlapping with syntaxin-6. Exocytosis is impaired in vti1a null cells, partly due to fewer Ca(2+)-channels at the plasma membrane, partly due to fewer vesicles of reduced size and synaptobrevin-2 content. In contrast, release kinetics and Ca(2+)-sensitivity remain unchanged, indicating that the final fusion...... reaction leading to transmitter release is unperturbed. Additional deletion of the closest related SNARE, vti1b, does not exacerbate the vti1a phenotype, and vti1b null cells show no secretion defects, indicating that vti1b does not participate in exocytosis. Long-term re-expression of vti1a (days...

  18. Flexural vibrations of finite composite poroelastic cylinders

    Indian Academy of Sciences (India)

    Abstract. This paper deals with the flexural vibrations of composite poroelastic solid cylinder consisting of two cylinders that are bonded end to end. Poroelastic materials of the two cylinders are different. The frequency equations for pervious and impervious surfaces are obtained in the framework of Biot's theory of wave.

  19. Consolidation of a poroelastic half-space with anisotropic ...

    Indian Academy of Sciences (India)

    The fully coupled Biot quasi-static theory of linear poroelasticity is used to study the consolidation of a poroelastic half-space caused by axisymmetric surface loads. The fluid and solid constituents of the poroelastic medium are compressible and its permeability in the vertical direction is different from its permeability in the ...

  20. Consolidation of a poroelastic half-space with anisotropic ...

    Indian Academy of Sciences (India)

    The fully coupled Biot quasi-static theory of linear poroelasticity is used to study the consolidation of a poroelastic half-space caused by axisymmetric surface loads.The fluid and solid constituents of the poroelastic medium are compressible and its permeability in the vertical direction is different from its permeability in the ...

  1. Approximate reflection coefficients for a thin VTI layer

    KAUST Repository

    Hao, Qi

    2017-09-18

    We present an approximate method to derive simple expressions for the reflection coefficients of P- and SV-waves for a thin transversely isotropic layer with a vertical symmetry axis (VTI) embedded in a homogeneous VTI background. The layer thickness is assumed to be much smaller than the wavelengths of P- and SV-waves inside. The exact reflection and transmission coefficients are derived by the propagator matrix method. In the case of normal incidence, the exact reflection and transmission coefficients are expressed in terms of the impedances of vertically propagating P- and S-waves. For subcritical incidence, the approximate reflection coefficients are expressed in terms of the contrast in the VTI parameters between the layer and the background. Numerical examples are designed to analyze the reflection coefficients at normal and oblique incidence, and investigate the influence of transverse isotropy on the reflection coefficients. Despite giving numerical errors, the approximate formulae are sufficiently simple to qualitatively analyze the variation of the reflection coefficients with the angle of incidence.

  2. Effect of Poroelasticity on Hydraulic Fracture Interactions

    DEFF Research Database (Denmark)

    Usui, Tomoya; Salimzadeh, Saeed; Paluszny, Adriana

    2017-01-01

    This study investigates, by performing finite element-based simulations, the influence of fluid leak-off and poroelasticity on growth of multiple hydraulic fractures that initiate from a single horizontal well. In this research, poroelastic deformation of the matrix is coupled with fluid flow...... in the fractures, and fluid flow in the rock matrix, in three dimensions. Effects of the fluid leakoff and poroelasticity on the propagation of the neighboring fractures are studied by varying the matrix permeability, and the Biot coefficient. Simulation results show that the stress induced by the opening...... of the fractures, and the stress induced by the fluid leak-off, each have the effect of locally altering the magnitudes and orientations of the principal stresses, hence altering the propagation direction of the fractures. The stress induced by the opening of the fractures tends to propagate both of the fractures...

  3. A poroelastic model of the lung

    CERN Document Server

    Berger, Lorenz; Burrowes, Kelly; Grau, Vicente; Tavener, Simon; Bordas, Rafel

    2014-01-01

    This work is motivated by the modelling of ventilation and deformation in the lung for understanding the biomechanics of respiratory diseases. The main contribution is the derivation and implementation of a lung model that tightly couples a poroelastic model of lung parenchyma to an airway fluid network. The poroelastic model approximates the porous structure of lung parenchyma using a continuum model that allows us to naturally model changes in physiology by spatially varying material parameters, whilst conserving mass and momentum within the tissue. The proposed model will also take advantage of realistic deformation boundary conditions obtained from image registration, to drive the simulation. A finite element method is presented to discretize the equations in a monolithic way to ensure convergence of the nonlinear problem. To demonstrate the coupling between the poroelastic medium and the network flow model numerical simulations on a realistic lung geometry are presented. These numerical simulations are a...

  4. Ultra Low Noise Poroelastic Road Surfaces

    Directory of Open Access Journals (Sweden)

    Jerzy A. Ejsmont

    2016-04-01

    Full Text Available Noise is one of the most important environmental problems related to road traffic. During the last decades, the noise emitted by the engines and powertrains of vehicles was greatly reduced and tires became a clearly dominant noise source. The article describes the concept of low noise poroelastic road surfaces that are composed of mineral and rubber aggregate bound by polyurethane resin. Those surfaces have a porous structure and are much more flexible than standard asphalt or cement concrete pavements due to high content of rubber aggregate and elastic binder. Measurements performed in several European countries indicate that such surfaces decrease tire/road noise between 7 dB and 12 dB with respect to reference surfaces such as dense asphalt concrete or stone matrix asphalt. Furthermore, poroelastic road surfaces ascertain the rolling resistance of car tires, which is comparable to classic pavements. One of the unforeseen properties of the poroelastic road surfaces is their ability to decrease the risks related to car fires with fuel spills. The article presents the road and laboratory results of noise, rolling resistance, and fire tests performed on a few types of poroelastic road surfaces.

  5. Tehnologija Angular 2 na primeru vtičnika Wordpress

    OpenAIRE

    Kenda, Mario

    2017-01-01

    V diplomskem delu je predstavljena implementacija vtičnika Wordpress, ki zagotavlja hitro in predvsem enostavno rezervacijo željenega turističnega aranžmaja. To dosežemo s tehnologijama Angular 2 in TypeScript ter vsemi drugimi povezanimi tehnologijami za razvoj spletnih aplikacij. Uporabniški vmesnik aplikacije je implementiran v jezikih HTML in CSS ter ogrodjem Bootstrap. Interakcija z uporabnikom ter logika aplikacije pa je implementirana s tehnologijama Angular 2 in jezikom TypeScript.

  6. Prestack exploding reflector modeling and migration in TI media

    KAUST Repository

    Wang, H.

    2014-01-01

    Prestack depth migration in anisotropic media, especially those that exhibit tilt, can be costly using reverse time migration (RTM). We present two-way spectral extrapolation of prestack exploding reflector modeling and migration (PERM) in acoustic transversely isotropic (TI) media. We construct systematic ways to evaluate phase angles and phase velocities in dip oriented TI (DTI), vertical TI (VTI) and tilted TI (TTI) media. Migration results from the Marmousi VTI model and the BP2007 TTI model show the feasibility of our approach.

  7. Variational continuum multiphase poroelasticity theory and applications

    CERN Document Server

    Serpieri, Roberto

    2017-01-01

    This book collects the theoretical derivation of a recently presented general variational macroscopic continuum theory of multiphase poroelasticity (VMTPM), together with its applications to consolidation and stress partitioning problems of interest in several applicative engineering contexts, such as in geomechanics and biomechanics. The theory is derived based on a purely-variational deduction, rooted in the least-Action principle, by considering a minimal set of kinematic descriptors. The treatment herein considered keeps a specific focus on the derivation of most general medium-independent governing equations. It is shown that VMTPM recovers paradigms of consolidated use in multiphase poroelasticity such as Terzaghi's stress partitioning principle and Biot's equations for wave propagation. In particular, the variational treatment permits the derivation of a general medium-independent stress partitioning law, and the proposed variational theory predicts that the external stress, the fluid pressure, and the...

  8. A parameterization study for elastic VTI Full Waveform Inversion of hydrophone components: synthetic and North Sea field data examples

    KAUST Repository

    Guitton, Antoine

    2017-08-15

    Choosing the right parameterization to describe a transversely isotropic medium with a vertical symmetry axis (VTI) allows us to match the scattering potential of these parameters to the available data in a way that avoids potential tradeoff and focus on the parameters to which the data are sensitive. For 2-D elastic full waveform inversion in VTI media of pressure components and for data with a reasonable range of offsets (as with those found in conventional streamer data acquisition systems), assuming that we have a kinematically accurate NMO velocity (vnmo) and anellipticity parameter η (or horizontal velocity, vh) obtained from tomographic methods, a parameterization in terms of horizontal velocity vh, η and ε is preferred to the more conventional parameterization in terms of vh, δ and ε. In the vh, η, ε parameterization and for reasonable scattering angles (<60o), ε acts as a “garbage collector” and absorbs most of the amplitude discrepancies; between modeled and observed data, more so when density ρ and shear-wave velocity vs are not inverted for (a standard practice with streamer data). On the contrary, in the vv, δ, ε parameterization, ε is mostly sensitive to large scattering angles, leaving vv exposed to strong leakages from ρ mainly. There assertions will be demonstrated on the synthetic Marmousi II as well as a North Sea OBC dataset, where inverting for the horizontal velocity rather than the vertical velocity yields more accurate models and migrated images.

  9. Coupling multipoint flux mixed finite element methodswith continuous Galerkin methods for poroelasticity

    KAUST Repository

    Wheeler, Mary

    2013-11-16

    We study the numerical approximation on irregular domains with general grids of the system of poroelasticity, which describes fluid flow in deformable porous media. The flow equation is discretized by a multipoint flux mixed finite element method and the displacements are approximated by a continuous Galerkin finite element method. First-order convergence in space and time is established in appropriate norms for the pressure, velocity, and displacement. Numerical results are presented that illustrate the behavior of the method. © Springer Science+Business Media Dordrecht 2013.

  10. Analysis of flexural wave propagation in poroelastic composite ...

    African Journals Online (AJOL)

    DR OKE

    and Tajuddin (2010) studied axially symmetric vibrations of composite poroelastic cylinders. Sharma and Sharma (2010) analyzed free vibration in a homogeneous transradially isotropic thermoelastic sphere. Flexural wave propagation in coated poroelastic cylinders is presented by Ahmed shah (2011). Tajuddin (2011) et ...

  11. Analysis of radial vibrations of poroelastic circular cylindrical shells ...

    African Journals Online (AJOL)

    Waves propagating in radial direction of a poroelastic circular cylinder are termed as radial vibrations. Radial vibrations of poroelastic circular cylindrical shell of infinite extent immersed in an inviscid elastic fluid are examined employing Biot's theory. Biot's model consists of an elastic matrix permeated by a network of ...

  12. Hybrid modal reduction for poroelastic materials

    Science.gov (United States)

    Batifol, Cédric; Ichchou, Mohamed N.; Galland, Marie-Annick

    2008-10-01

    A modal-like projection method for poroelastic materials is proposed and implemented for finite element calculations. Non-physical Dirichlet conditions are imposed at the junction interface, involving constrained fluid displacements and free solid displacements. The ( u,U) formulation is used. The resulting frequency-dependent eigenproblem is solved without simplification using the non-linear Arnoldi algorithm. The projection subspace is spanned by calculated dynamic modes and fluid static boundary functions. A convergence study is performed and results are compared to classical Craig and Bampton and MacNeal approaches. The hybrid basis proves to be efficient. To cite this article: C. Batifol et al., C. R. Mecanique 336 (2008).

  13. Efficient simulations of fluid flow coupled with poroelastic deformations in pleated filters

    KAUST Repository

    Calo, Victor M.

    2015-04-27

    Pleated filters are broadly used for various applications. In certain cases, especially in solid-liquid separation case, the filtering media may get deflected and that may change the overall performance characteristics of the filter. From the modeling point of view, this is a challenging multiphysics problem, namely the interaction of the fluid with a so-called poroelastic structure. This work focuses on the development of an algorithm for the simulation of the Fluid Porous Structure Interaction (FPSI) problem in the case of pleated filtering media. The first part of the work is concerned with the development of a robust and accurate numerical method for solving the Stokes-Brinkman system of equations on quadrilateral grids. The mathematical model describes a free fluid flow coupled with a flow in porous media in a domain that contains the filtering media. To discretize the complex computational domain we use quadrilateral boundary fitted grids which resolve porous-fluid interfaces. The Stokes-Brinkman system of equations is discretized here using a sophisticated finite volume method, namely multi-point flux approximation (MPFA) O-method. MPFA is widely used, e.g., in solving scalar elliptic equations with full tensor and highly varying coefficients and/or solving on heterogeneous non-orthogonalgrids. Up to the authors’ knowledge, there was no investigation of MPFA discretization for Stokes-Brinkman problems, and this study aims to fill this gap. Some numerical experiments are presented in order to demonstrate the robustness of the proposed numerical algorithm[1]. The second part of this study focuses on the coupling of the flow model with the deflection of the filtering media. For the consideration of the FPSI problem in 3D, the classical Biot system describes coupled flow and deformations in a porous body due to difference in the upstream and downstream pressures. Solving the Biot system of equations is complicated and requires a significant amount of

  14. An analytical poroelastic model for ultrasound elastography imaging of tumors

    Science.gov (United States)

    Tauhidul Islam, Md; Chaudhry, Anuj; Unnikrishnan, Ginu; Reddy, J. N.; Righetti, Raffaella

    2018-01-01

    The mechanical behavior of biological tissues has been studied using a number of mechanical models. Due to the relatively high fluid content and mobility, many biological tissues have been modeled as poroelastic materials. Diseases such as cancers are known to alter the poroelastic response of a tissue. Tissue poroelastic properties such as compressibility, interstitial permeability and fluid pressure also play a key role for the assessment of cancer treatments and for improved therapies. At the present time, however, a limited number of poroelastic models for soft tissues are retrievable in the literature, and the ones available are not directly applicable to tumors as they typically refer to uniform tissues. In this paper, we report the analytical poroelastic model for a non-uniform tissue under stress relaxation. Displacement, strain and fluid pressure fields in a cylindrical poroelastic sample containing a cylindrical inclusion during stress relaxation are computed. Finite element simulations are then used to validate the proposed theoretical model. Statistical analysis demonstrates that the proposed analytical model matches the finite element results with less than 0.5% error. The availability of the analytical model and solutions presented in this paper may be useful to estimate diagnostically relevant poroelastic parameters such as interstitial permeability and fluid pressure, and, in general, for a better interpretation of clinically-relevant ultrasound elastography results.

  15. Poroelastic finite-difference modeling for ultrasonic waves in digital porous cores

    Science.gov (United States)

    Fu, Li-Yun; Zhang, Yan; Pei, Zhenglin; Wei, Wei; Zhang, Luxin

    2014-06-01

    Scattering attenuation in short wavelengths has long been interesting to geophysicists. Ultrasonic coda waves, observed as the tail portion of ultrasonic wavetrains in laboratory ultrasonic measurements, are important for such studies where ultrasonic waves interact with small-scale random heterogeneities on a scale of micrometers, but often ignored as noises because of the contamination of boundary reflections from the side ends of a sample core. Numerical simulations with accurate absorbing boundary can provide insight into the effect of boundary reflections on coda waves in laboratory experiments. The simulation of wave propagation in digital and heterogeneous porous cores really challenges numerical techniques by digital image of poroelastic properties, numerical dispersion at high frequency and strong heterogeneity, and accurate absorbing boundary schemes at grazing incidence. To overcome these difficulties, we present a staggered-grid high-order finite-difference (FD) method of Biot's poroelastic equations, with an arbitrary even-order (2 L) accuracy to simulate ultrasonic wave propagation in digital porous cores with strong heterogeneity. An unsplit convolutional perfectly matched layer (CPML) absorbing boundary, which improves conventional PML methods at grazing incidence with less memory and better computational efficiency, is employed in the simulation to investigate the influence of boundary reflections on ultrasonic coda waves. Numerical experiments with saturated poroelastic media demonstrate that the 2 L FD scheme with the CPML for ultrasonic wave propagation significantly improves stability conditions at strong heterogeneity and absorbing performance at grazing incidence. The boundary reflections from the artificial boundary surrounding the digital core decay fast with the increase of CPML thicknesses, almost disappearing at the CPML thickness of 15 grids. Comparisons of the resulting ultrasonic coda Q sc values between the numerical and experimental

  16. Ashes mechanical performance - VTI's material database; Askors materialtekniska funktion - VTI's materialdatabas

    Energy Technology Data Exchange (ETDEWEB)

    Arvidsson, Haakan; Loorents, Karl-Johan [Swedish National Road and Transport Research Inst., inkoeping (Sweden)

    2005-05-01

    The project has compiled, analysed and stored data from material testing performed at the Swedish National Road and Transportation Research Institute (VTI). Materials are predominantly ashes that have been assessed by dynamic cyclic triaxial tests. Testing has been performed over a longer period of time; this has resulted in an extensive number of both tested materials and individual samples. The work has focused on the engineering performance of ashes. Test results are stored in the database AllAska; a database developed within the Swedish Thermal Research Institute (Vaermeforsk) research program 'Environmentally correct utilization of ashes'. AllAska shall provide storage and availability of the R and D program results. For each sample stored in AllAska there is information about the type of material, the performed test methods and test results are given. As testing has been performed over a longer period of time the interpretation of the test results should consider material handling and incineration techniques. For example a change in the incineration will have an effect on the material, i.e. its material properties. Parts of the test results have already been published, but an extensive compilation has been missing. It is expected that this study will provide a valuable reference for the continuous research and development activities within this research area. A special interest is believed to come from the field of test methods and methods for determining the functional properties of the material. The use of ashes as a construction material is not in wide use compared to gravel and crushed rock aggregates. However, with material parameters such as low density and good bearing capacity they are particularly adaptable in some construction applications. Certain ashes are technically a material substitute for natural gravel. But the use is limited, perhaps due to a lack of knowledge about ashes. Certain aspects, such as technical and environmental long

  17. Homotypic vacuole fusion requires VTI11 and is regulated by phosphoinositides.

    Science.gov (United States)

    Zheng, Jiameng; Han, Sang Won; Rodriguez-Welsh, Maria Fernanda; Rojas-Pierce, Marcela

    2014-06-01

    Most plant cells contain a large central vacuole that is essential to maintain cellular turgor. We report a new mutant allele of VTI11 that implicates the SNARE protein VTI11 in homotypic fusion of protein storage and lytic vacuoles. Fusion of the multiple vacuoles present in vti11 mutants could be induced by treatment with Wortmannin and LY294002, which are inhibitors of Phosphatidylinositol 3-Kinase (PI3K). We provide evidence that Phosphatidylinositol 3-Phosphate (PtdIns(3)P) regulates vacuole fusion in vti11 mutants, and that fusion of these vacuoles requires intact microtubules and actin filaments. Finally, we show that Wortmannin also induced the fusion of guard cell vacuoles in fava beans, where vacuoles are naturally fragmented after ABA-induced stomata closure. These results suggest a ubiquitous role of phosphoinositides in vacuole fusion, both during the development of the large central vacuole and during the dynamic vacuole remodeling that occurs as part of stomata movements. © The Author 2014. Published by the Molecular Plant Shanghai Editorial Office in association with Oxford University Press on behalf of CSPB and IPPE, SIBS, CAS.

  18. Effective equations governing an active poroelastic medium

    Science.gov (United States)

    2017-01-01

    In this work, we consider the spatial homogenization of a coupled transport and fluid–structure interaction model, to the end of deriving a system of effective equations describing the flow, elastic deformation and transport in an active poroelastic medium. The ‘active’ nature of the material results from a morphoelastic response to a chemical stimulant, in which the growth time scale is strongly separated from other elastic time scales. The resulting effective model is broadly relevant to the study of biological tissue growth, geophysical flows (e.g. swelling in coals and clays) and a wide range of industrial applications (e.g. absorbant hygiene products). The key contribution of this work is the derivation of a system of homogenized partial differential equations describing macroscale growth, coupled to transport of solute, that explicitly incorporates details of the structure and dynamics of the microscopic system, and, moreover, admits finite growth and deformation at the pore scale. The resulting macroscale model comprises a Biot-type system, augmented with additional terms pertaining to growth, coupled to an advection–reaction–diffusion equation. The resultant system of effective equations is then compared with other recent models under a selection of appropriate simplifying asymptotic limits. PMID:28293138

  19. Mapping moveout approximations in TI media

    KAUST Repository

    Stovas, Alexey

    2013-11-21

    Moveout approximations play a very important role in seismic modeling, inversion, and scanning for parameters in complex media. We developed a scheme to map one-way moveout approximations for transversely isotropic media with a vertical axis of symmetry (VTI), which is widely available, to the tilted case (TTI) by introducing the effective tilt angle. As a result, we obtained highly accurate TTI moveout equations analogous with their VTI counterparts. Our analysis showed that the most accurate approximation is obtained from the mapping of generalized approximation. The new moveout approximations allow for, as the examples demonstrate, accurate description of moveout in the TTI case even for vertical heterogeneity. The proposed moveout approximations can be easily used for inversion in a layered TTI medium because the parameters of these approximations explicitly depend on corresponding effective parameters in a layered VTI medium.

  20. Wave propagation in sandwich panels with a poroelastic core.

    Science.gov (United States)

    Liu, Hao; Finnveden, Svante; Barbagallo, Mathias; Arteaga, Ines Lopez

    2014-05-01

    Wave propagation in sandwich panels with a poroelastic core, which is modeled by Biot's theory, is investigated using the waveguide finite element method. A waveguide poroelastic element is developed based on a displacement-pressure weak form. The dispersion curves of the sandwich panel are first identified as propagating or evanescent waves by varying the damping in the panel, and wave characteristics are analyzed by examining their motions. The energy distributions are calculated to identify the dominant motions. Simplified analytical models are also devised to show the main physics of the corresponding waves. This wave propagation analysis provides insight into the vibro-acoustic behavior of sandwich panels lined with elastic porous materials.

  1. A nonlinear poroelastic model for the periodontal ligament

    Science.gov (United States)

    Favino, Marco; Bourauel, Christoph; Krause, Rolf

    2016-05-01

    A coupled elastic-poroelastic model for the simulation of the PDL and the adjacent tooth is presented. A poroelastic constitutive material model for the periodontal ligament (PDL) is derived. The solid phase is modeled by means of a Fung material law, accounting for large displacements and strains. Numerical solutions are performed by means of a multigrid Newton method to solve the arising large nonlinear system. Finally, by means of numerical experiments, the biomechanical response of the PDL is studied. In particular, the effect of the hydraulic conductivity and of the mechanical parameters of a Fung potential is investigated in two realistic applications.

  2. A hydrologic view on Biot's theory of poroelasticity

    Energy Technology Data Exchange (ETDEWEB)

    Silin, D.B.; Korneev, V.A.; Goloshubin, G.M.; Patzek, T.W.

    2004-01-13

    The main objective of this work is to obtain a simplified asymptotic representation of the reflection of seismic signal from a fluid-saturated porous medium in the low-frequency domain. In the first part, we derive the equations of low-frequency harmonic waves in a fluid-saturated elastic porous medium from the basic concepts of filtration theory. We demonstrate that the obtained equations can be related to the poroelasticity model of Frenkel-Gassmann-Biot, and to pressure diffusion model routinely used in well test analysis as well. We thus try to put the poroelastic and filtration theories on the same ground. We study the reflection of a low-frequency signal from a plane interface between elastic and elastic fluid-saturated porous media. We obtain an asymptotic scaling of the frequency-dependent component of the reflection coefficient with respect to a dimensionless parameter depending on the frequency of the signal and the reservoir fluid mobility. We also investigate the impact of the relaxation time and tortuosity on this scaling.

  3. Ultrasonic wave propagation in heterogeneous elastic and poroelastic media

    NARCIS (Netherlands)

    Jocker, J.

    2005-01-01

    The influence of small- and large-scale heterogeneities on an incident wavefield was investigated in ultrasonic experiments. The field generated by conventional piezoelectric transducers was investigated separately. It was confirmed that the far-field diffraction was correctly predicted by

  4. Plain strain problem of poroelasticity using eigenvalue approach

    Indian Academy of Sciences (India)

    A plain strain problem of an isotropic elastic liquid-saturated porous medium in poroelasticity has been studied. The eigenvalue approach using the Laplace and Fourier transforms has been employed and these transforms have been inverted by using a numerical technique. An application of infinite space with ...

  5. Wave propagation in a general anisotropic poroelastic medium ...

    Indian Academy of Sciences (India)

    The medium considered is a general anisotropic poroelastic (APE) solid with a viscous fluid saturating its pores of anisotropic permeability. The wave propagation phenomenon in a saturated porous medium is explained through two relations. One defines modified Christoffel equations for the propagation of plane harmonic ...

  6. Investigation of torsional vibrations in thick walled hollow poroelastic ...

    Indian Academy of Sciences (India)

    Abstract. This paper deals with the study of torsional vibrations of thick walled hollow poroelastic cylinder using Biot's extension theory. Considering the boundaries to be stress free, the frequency equation is obtained in the presence of dissipation which is transcendental and complex valued in nature. In the special case of ...

  7. Investigation of torsional vibrations in thick walled hollow poroelastic ...

    Indian Academy of Sciences (India)

    This paper deals with the study of torsional vibrations of thick walled hollow poroelastic cylinder using Biot's extension theory. Considering the boundaries to be stress free, the frequency equation is obtained in the presence of dissipation which is transcendental and complex valued in nature. In the special case of ...

  8. Torsional vibrations of infinite composite poroelastic cylinders | Shah ...

    African Journals Online (AJOL)

    The displacements of second and third torsional modes are determined and presented graphically for the ratio of radius of composite poroelastic solid cylinder to the radius of the inner solid cylinder. Results of previous works are shown as special case of the present analysis. By ignoring liquid effects, the results of purely ...

  9. Efficient Wavefield Extrapolation In Anisotropic Media

    KAUST Repository

    Alkhalifah, Tariq

    2014-07-03

    Various examples are provided for wavefield extrapolation in anisotropic media. In one example, among others, a method includes determining an effective isotropic velocity model and extrapolating an equivalent propagation of an anisotropic, poroelastic or viscoelastic wavefield. The effective isotropic velocity model can be based upon a kinematic geometrical representation of an anisotropic, poroelastic or viscoelastic wavefield. Extrapolating the equivalent propagation can use isotopic, acoustic or elastic operators based upon the determined effective isotropic velocity model. In another example, non-transitory computer readable medium stores an application that, when executed by processing circuitry, causes the processing circuitry to determine the effective isotropic velocity model and extrapolate the equivalent propagation of an anisotropic, poroelastic or viscoelastic wavefield. In another example, a system includes processing circuitry and an application configured to cause the system to determine the effective isotropic velocity model and extrapolate the equivalent propagation of an anisotropic, poroelastic or viscoelastic wavefield.

  10. Additional evidence supports association of common genetic variants in VTI1A and ETFA with increased risk of glioma susceptibility.

    Science.gov (United States)

    Wang, Ning; Deng, Zhong; Wang, Maode; Li, Ruichun; Xu, Gaofeng; Bao, Gang

    2017-04-15

    VTI1A and ETFA were identified recently as susceptibility genes for non-glioblastoma (GBM) of glioma risk in European populations, but the genetic etiology and pathogenesis of glioma have not been fully elucidated. Here, we aimed to investigate whether common genetic variants in VTI1A and ETFA predispose Han Chinese individuals to glioma. The association of thirteen common tagging single nucleotide polymorphisms (SNPs) in VTI1A and ETFA genes with glioma were assessed in a hospital-based case-control study including 473 non-GBM of glioma patients and 1046 cancer-free controls. Two SNPs (rs11196067 in VTI1A and rs1801591 in ETFA) were found to be significantly associated with non-GBM of glioma risk (rs11196067, adjusted P=0.00018, adjusted odds ratio (OR)=1.37, 95% confidence interval (CI)=1.16-1.61; rs1801591, adjusted P=0.000022, adjusted OR=1.72, 95% CI=1.34-2.20). In further stratified analysis, they were both more pronounced in the adult subgroup. In haplotype-based analysis, two haplotypes were identified to be significant association with glioma. The haplotype "TGA" (P=0.002) in VTI1A and the haplotype "ACA" (Pglioma risk respectively, compared with corresponding non-carriers. In summary, our results indicate that genetic variants in VTI1A and ETFA may modify individual susceptibility to non-GBM of glioma in the Han Chinese population and support the role of the VTI1A and ETFA genes in the occurrence of glioma. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. A Poroelastic Approach for Quantifying Gel Network Properties

    Science.gov (United States)

    Chan, Edwin; Nadermann, Nichole; Feldman, Katie; Davis, Eric

    The unique chemical and structural properties of polymer gels has led to the application of these materials in various membrane-based technologies where selective transport is critical to device performance. Characterizing the chemical and structural properties of a gel is critical to understanding its transport behavior. yet quantifying these properties is nontrivial as it typically requires multiple measurement techniques. In this talk, we demonstrate poroelastic relaxation indentation (PRI) as a single measurement tool to characterize the swelling, mechanical and transport properties of model poly(ethylene glycol)-based hydrogel systems. By applying the appropriate thermodynamic polymer network model and the linear theory of poroelasticity, we are able to use the results from PRI to extract the thermodynamic parameters, elastic modulus, water permeability and mesh size of these gels. We validate these results with small angle neutron scattering to illustrate the applicability of the PRI measurement technique for studying these membrane-like materials.

  12. Multiscale modeling and topology optimization of poroelastic actuators

    DEFF Research Database (Denmark)

    Andreasen, Casper Schousboe; Sigmund, Ole

    2012-01-01

    This paper presents a method for design of optimized poroelastic materials which under internal pressurization turn into actuators for application in, for example, linear motors. The actuators are modeled in a two-scale fluid–structure interaction approach. The fluid saturated material microstruc...... microstructure is optimized using topology optimization in order to achieve a better macroscopic performance quantified by vertical or torsional deflections. Constraints are introduced to ensure a certain deflection/extension ratio of the actuator....

  13. Poroelastic response of geothermal reservoirs during hydraulic stimulation treatment

    Science.gov (United States)

    Jacquey, Antoine; Urpi, Luca; Cacace, Mauro; Blöcher, Guido; Zimmermann, Günter; Scheck-Wenderoth, Magdalena

    2017-04-01

    Enhanced geothermal systems (EGS) are engineered reservoirs developed to extract heat from low permeability and low porosity geological formations. Cyclic hydraulic stimulation treatments are used in such a context to create hydraulic fractures, minimizing the fluid injected volume (recently proposed as a mitigation strategy for induced seismicity) to gain access to the target formation fluids, drain the geothermal fluid and therefore increase the overall productivity of the geothermal reservoir. During these operations, successive cycles of injection of high flow rates are conducted to decrease the effective minimum principal stress, and therefore the tensile strength of the material, developing a hydraulic fracture. Opening of these newly developed fractures induces an additional deformation of the reservoir rocks. In this study, the poroelastic response resulting from induced deformation during cyclic hydraulic stimulation treatment of a well is investigated using hydromechanical coupling between pore pressure variations and solid rock deformation. The effects of this poroelastic response on the hydromechanical state of a reservoir is illustrated by means of field measurements of a cyclic hydraulic stimulation treatment conducted at the Groß Schönebeck geothermal research site in August 2007. This study points out that a nonlinear pore pressure response arises within the reservoir rocks due to the deformation generated by the stimulation treatment. It is shown here that the 3D poroelastic response of the reservoir leads to an unexpected quasi-instantaneous pore pressure increase in a neighbor monitoring well located approximatively 475 m away from the stimulated well at reservoir depth.

  14. Saturated poroelastic actuators generated by topology optimization

    DEFF Research Database (Denmark)

    Andreasen, Casper Schousboe; Sigmund, Ole

    2011-01-01

    In this paper the fluid-structure interaction problem of a saturated porous media is considered. The pressure coupling properties of porous saturated materials change with the microstructure and this is utilized in the design of an actuator using a topology optimized porous material. By maximizing...... the coupling of internal fluid pressure and elastic shear stresses a slab of the optimized porous material deflects/deforms when a pressure is imposed and an actuator is created. Several phenomenologically based constraints are imposed in order to get a stable force transmitting actuator....

  15. Effect of normal stress under an excitation in poroelastic flat slabs ...

    African Journals Online (AJOL)

    Biot's poroelastic theory is employed to investigate stresses under an excitation in an infinite poroelastic slab of arbitrary thickness. Both for pervious and impervious surfaces, the radial normal stress is obtained, and in the neighbourhood of the centre, the same is computed as function of thickness of the slab. Numerical ...

  16. The value of virtual touch tissue image (VTI) and virtual touch tissue quantification (VTQ) in the differential diagnosis of thyroid nodules

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Feng-Juan, E-mail: 148126008@qq.com; Han, Ruo-Ling, E-mail: 13832191660@163.com; Zhao, Xin-Ming, E-mail: 18531117263@163.com

    2014-11-15

    Highlights: • All nodules in the research were confirmed by histopathology. • The classification method of VTI was easy to learn. • VTQ could provide quantitative elasticity measurements for thyroid nodules. • VTI classification could provide semi-quantitative elasticity analysis. • The area ratio could show invasive extent of malignant tumor. - Abstract: Objectives: To explore the value of virtual touch tissue image (VTI) and virtual touch tissue quantification (VTQ) in the differential diagnosis of thyroid nodules. Methods: One-hundred and seven patients with 113 thyroid nodules were performed conventional ultrasound and acoustic radiation force impulse (ARFI) elastography. The stiffness of the nodules on virtual touch tissue image (VTI) was graded, and the area ratios (AR) of nodules on VTI images versus on B-mode images were calculated. Shear wave velocity (SWV) within the thyroid nodules were measured using virtual touch tissue quantification (VTQ) technique. The pathological diagnosis as the gold standard draws the receiver-operating characteristic curve (ROC) to find the cut-off point of VTI grades, AR and SWV to predict thyroid cancer. Results: The difference in VTI grades of malignant and benign nodules was statistically significant (P < 0.05), as well as in AR and SWV. There was no significant difference in the AR of nodules or the SWV of nodules in benign group or in malignant group. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of VTI grades, AR, and SWV in the differential diagnosis of thyroid nodules were calculated. There was no significant difference in diagnostic accuracy among the three methods. Conclusion: VTI grades, AR of nodules on VTI images versus on B-mode images and SWV within the nodules can help the differential diagnosis of thyroid nodules.

  17. Effects of poroelastic coefficients on normal vibration modes in vocal-fold tissues.

    Science.gov (United States)

    Tao, Chao; Liu, Xiaojun

    2011-02-01

    The vocal-fold tissue is treated as a transversally isotropic fluid-saturated porous material. Effects of poroelastic coefficients on eigenfrequencies and eigenmodes of the vocal-fold vibration are investigated using the Ritz method. The study demonstrates that the often-used elastic model is only a particular case of the poroelastic model with an infinite fluid-solid mass coupling parameter. The elastic model may be considered appropriate for the vocal-fold tissue when the absolute value of the fluid-solid mass coupling parameter is larger than 10(5) kg/m(3). Otherwise, the poroelastic model may be more accurate. The degree of compressibility of the vocal tissue can also been described by the poroelastic coefficients. Finally, it is revealed that the liquid and solid components in a poroelastic model could have different modal shapes when the coupling between them is weak. The mode decoupling could cause desynchronization and irregular vibration of the folds.

  18. Optimal poroelastic layer sequencing for sound transmission loss maximization by topology optimization method.

    Science.gov (United States)

    Lee, Joong Seok; Kim, Eun Il; Kim, Yoon Young; Kim, Jung Soo; Kang, Yeon June

    2007-10-01

    Optimal layer sequencing of a multilayered acoustical foam is solved to maximize its sound transmission loss. A foam consisting of air and poroelastic layers can be optimized when a limited amount of a poroelastic material is allowed. By formulating the sound transmission loss maximization problem as a one-dimensional topology optimization problem, optimal layer sequencing and thickness were systematically found for several single and ranges of frequencies. For optimization, the transmission losses of air and poroelastic layers were calculated by the transfer matrix derived from Biot's theory. By interpolating five intrinsic parameters among several poroelastic material parameters, distinct air-poroelastic layer distributions were obtained; no filtering or postprocessing was necessary. The optimized foam layouts by the proposed method were shown to differ depending on the frequency bands of interest.

  19. Acoustic VTI wavefield tomography of P-wave surface and VSP data

    KAUST Repository

    Li, Vladimir

    2017-08-17

    Transversely isotropic (TI) models have become standard in depth imaging and are often used in waveform inversion. Here, we develop a robust wave-equation-based tomographic algorithm for building acoustic VTI (transversely isotropic with a vertical symmetry axis) velocity models from P-wave surface reflection and vertical seismic profiling (VSP) data. Wavefield extrapolation is performed with an integral operator to avoid generating shear-wave artifacts. Focusing energy in extended images produced by reverse-time migration (RTM) makes it possible to update the zero-dip NMO velocity Vnmo and the anellipiticity parameter η. To constrain the anisotropy coefficient δ and improve the accuracy in Vnmo and η, we employ borehole information by introducing an additional objective-function term designed to fit VSP data. Image-guided smoothing is applied to both data- and image-domain gradients to steer the inversion towards geologically plausible solutions. Testing on the VTI Marmousi model shows that the joint inversion of surface and VSP data helps estimate all three relevant medium parameters.

  20. Aeroelastic analysis of versatile thermal insulation (VTI) panels with pinched boundary conditions

    Science.gov (United States)

    Carrera, Erasmo; Zappino, Enrico; Patočka, Karel; Komarek, Martin; Ferrarese, Adriano; Montabone, Mauro; Kotzias, Bernhard; Huermann, Brian; Schwane, Richard

    2014-03-01

    Launch vehicle design and analysis is a crucial problem in space engineering. The large range of external conditions and the complexity of space vehicles make the solution of the problem really challenging. The problem considered in the present work deals with the versatile thermal insulation (VTI) panel. This thermal protection system is designed to reduce heat fluxes on the LH2 tank during the long coasting phases. Because of the unconventional boundary conditions and the large-scale geometry of the panel, the aeroelastic behaviour of VTI is investigated in the present work. Known available results from literature related to similar problem, are reviewed by considering the effect of various Mach regimes, including boundary layer thickness effects, in-plane mechanical and thermal loads, non-linear effects and amplitude of limit cycle oscillations. A dedicated finite element model is developed for the supersonic regime. The models used for coupling the orthotropic layered structural model with Piston Theory aerodynamic models allow the calculations of flutter conditions in case of curved panels supported in a discrete number of points. An advanced computational aeroelasticity tool is developed using various dedicated commercial softwares (CFX, ZAERO, EDGE). A wind tunnel test campaign is carried out to assess the computational tool in the analysis of this type of problem.

  1. The basic components of residual migration in VTI media using anisotropy continuation

    KAUST Repository

    Alkhalifah, Tariq Ali

    2011-03-24

    We introduce anisotropy continuation as a process which relates changes in seismic images to perturbations in the anisotropic medium parameters. This process is constrained by two kinematic equations, one for perturbations in the normal-moveout (NMO) velocity and the other for perturbations in the dimensionless anisotropy parameter ?. We consider separately the case of post-stack migration and show that the kinematic equations in this case can be solved explicitly by converting them to ordinary differential equations using the method of characteristics. When comparing the results of kinematic analytical computations with synthetic numerical experiments confirms the theoretical accuracy of the method.

  2. Dynamic model of open shell structures buried in poroelastic soils

    Science.gov (United States)

    Bordón, J. D. R.; Aznárez, J. J.; Maeso, O.

    2017-08-01

    This paper is concerned with a three-dimensional time harmonic model of open shell structures buried in poroelastic soils. It combines the dual boundary element method (DBEM) for treating the soil and shell finite elements for modelling the structure, leading to a simple and efficient representation of buried open shell structures. A new fully regularised hypersingular boundary integral equation (HBIE) has been developed to this aim, which is then used to build the pair of dual BIEs necessary to formulate the DBEM for Biot poroelasticity. The new regularised HBIE is validated against a problem with analytical solution. The model is used in a wave diffraction problem in order to show its effectiveness. It offers excellent agreement for length to thickness ratios greater than 10, and relatively coarse meshes. The model is also applied to the calculation of impedances of bucket foundations. It is found that all impedances except the torsional one depend considerably on hydraulic conductivity within the typical frequency range of interest of offshore wind turbines.

  3. Ferromagnetism in half-metallic quaternary FeVTiAl Heusler compound

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, Tahir Mohiuddin; Bhat, Idris Hamid; Yousuf, Saleem; Gupta, Dinesh C., E-mail: sosfizix@yahoo.co.in [Condensed Matter Theory Group, School of Studies in Physics, Jiwaji University, Gwalior – 474 011 (MP) (India)

    2016-05-23

    The electronic structure and magnetic properties of FeVTiAl quaternary Heusler alloy have been investigated within the density functional theory framework. The material was found completely spin-polarized half-metallic Ferromagnet in the ground state with F-43m structure. The structural stability was further confirmed by calculating different elastic constants in the cubic phase. Present study predicts an energy band gap of 0.72 eV calculated in localized minority spin channel at an equilibrium lattice parameter of 6.0Å. The calculated total spin magnetic moment of 2 µ{sub B}/f.u. is in agreement with the Slater-Pauling rule for full Heusler alloys.

  4. Gradient for the acoustic VTI full waveform inversion based on the instantaneous traveltime sensitivity kernels

    KAUST Repository

    Djebbi, Ramzi

    2015-08-19

    The instantaneous traveltime is able to reduce the non-linearity of full waveform inversion (FWI) that originates from the wrapping of the phase. However, the adjoint state method in this case requires a total of 5 modeling calculations to compute the gradient. Also, considering the larger modeling cost for anisotropic wavefield extrapolation and the necessity to use a line-search algorithm to estimate a step length that depends on the parameters scale, we propose to calculate the gradient based on the instantaneous traveltime sensitivity kernels. We, specifically, use the sensitivity kernels computed using dynamic ray-tracing to build the gradient. The resulting update is computed using a matrix decomposition and accordingly the computational cost is reduced. We consider a simple example where an anomaly is embedded into a constant background medium and we compute the update for the VTI wave equation parameterized using vh, η and ε.

  5. Effective equations for fluid-structure interaction with applications to poroelasticity

    KAUST Repository

    Brown, Donald

    2012-11-05

    Modeling of fluid-solid interactions in porous media is a challenging and computationally demanding task. Due to the multiscale nature of the problem, simulating the flow and mechanics by direct numerical simulation is often not feasible and an effective model is preferred. In this work, we formally derive an effective model for Fluid-Structure Interaction (FSI). In earlier work, assuming infinitesimal pore-scale deformations, an effective poroelastic model of Biot was derived. We extend this model to a nonlinear Biot model that includes pore-scale deformation into the effective description. The main challenge is the difference in coordinate systems of the fluid and solid equations. This is circumvented by utilizing the Arbitrary Lagrange-Eulerian (ALE) formulation of the FSI equations, giving a unified frame in which to apply two-scale asymptotic techniques. In the derived nonlinear Biot model, the local cell problem are coupled to the macroscopic equations via the effective coefficients. These coefficients may be viewed as tabular functions of the macroscopic parameters. After simplifying this dependence, we assume the coefficients depend on macroscopic pressure only. Using a three dimensional pore geometry we calculate, as a proof-of-concept example, the effective permeability and Biot coefficients for various values or pressure. We observe that, for this geometry, a stronger pressure dependence on flow quantities than on mechanically based effective quantities. © 2014 Taylor & Francis Group, LLC.

  6. Two-dimensional poroelastic acoustical foam shape design for absorption coefficient maximization by topology optimization method.

    Science.gov (United States)

    Lee, Joong Seok; Kim, Yoon Young; Kim, Jung Soo; Kang, Yeon June

    2008-04-01

    Optimal shape design of a two-dimensional poroelastic acoustical foam is formulated as a topology optimization problem. For a poroelastic acoustical system consisting of an air region and a poroelastic foam region, two different physical regions are continuously changed in an iterative design process. To automatically account for the moving interfaces between two regions, we propose a new unified model to analyze the whole poroelastic acoustical foam system with one set of governing equations; Biot's equations are modified with a material property interpolation from a topology optimization method. With the unified analysis model, we carry out two-dimensional optimal shape design of a poroelastic acoustical foam by a gradient-based topology optimization setting. The specific objective is the maximization of the absorption coefficient in low and middle ranges of frequencies with different amounts of a poroelastic material. The performances of the obtained shapes are compared with those of well-known wedge shapes, and the improvement of absorption is physically interpreted.

  7. Temperature and pressure dependent structural and thermo-physical properties of quaternary CoVTiAl alloy

    Science.gov (United States)

    Yousuf, Saleem; Gupta, Dinesh C.

    2017-09-01

    Investigation of band structure and thermo-physical response of new quaternary CoVTiAl Heusler alloy within the frame work of density functional theory has been analyzed. 100% spin polarization with ferromagnetic stable ground state at the optimized lattice parameter of 6.01 Å is predicted for the compound. Slater-Pauling rule for the total magnetic moment of 3 μB and an indirect semiconducting behavior is also seen for the compound. In order to perfectly analyze the thermo-physical response, the lattice thermal conductivity and thermodynamic properties have been calculated. Thermal effects on some macroscopic properties of CoVTiAl are predicted using the quasi-harmonic Debye model, in which the lattice vibrations are taken into account. The variations of the lattice constant, volume expansion coefficient, heat capacities, and Debye temperature with pressure and temperature in the ranges of 0 GPa to 15 GPa and 0 K to 800 K have been obtained.

  8. The impact of ventilation tubes in otitis media on the risk of cholesteatoma on a national level.

    Science.gov (United States)

    Djurhuus, Bjarki Ditlev; Christensen, Kaare; Skytthe, Axel; Faber, Christian Emil

    2015-04-01

    To estimate the impact of treatment with middle ear ventilation tube insertion (VTI) in children with otitis media (OM) on the risk of cholesteatoma on a national level. Data were obtained from the Danish National Patient Register, the National Health Service Register and Statistics Denmark. Cumulative incidence proportions were estimated by the Kaplan-Meier method and hazard ratios with Cox regression analysis. The first surgically treated middle ear cholesteatoma in a child (STMEC1) was considered an event. A total of 217,206 children, born after December 31, 1996, who had VTI from January 1, 1997 to August 31, 2011 were identified. Of these, 374 subsequently had a STMEC1. A corresponding 36,981 children without any VTI were identified for comparison using a random 5% sample of the Danish population. Of these, 5 had a STMEC1. The cumulative incidence proportion with STMEC1 at 12 years of age for children with 0, 1, 2, 3, and ≥4 VTI's was 0.04% (95% confidence interval 0.02-0.12%), 0.21% (0.18-0.26%), 0.35% (0.28-0.43%), 0.40% (0.30-0.54%), and 0.55% (0.44-0.70%), respectively. In the regression model each additional year of age before the first VTI increased the risk of STMEC1 by 54% (47-63%), while each additional year between two successive tube insertions increased the risk by 28% (15-43%). We found that prolonged OM requiring multiple VTIs was associated with an increased risk of STMEC1. Early age at first VTI and short time between two VTIs was associated with a lower risk of STMEC1. This may be the result of reduced time with negative middle ear pressure and OM. However, these findings may be susceptible to selection bias, as age at first VTI and time between VTIs, as well as the outcome variable, STMEC1, may all depend on the underlying indication for VTI. In short the present study suggests that treatment with VTI in children with OM reduces the risk of STMEC1 on a population level. However, for the individual child the absolute risk reduction is very

  9. Quantitative Analysis on Carbide Precipitation in V-Ti Microalloyed TRIP Steel Containing Aluminum

    Directory of Open Access Journals (Sweden)

    Fu Shiyu

    2016-01-01

    Full Text Available Introducing fine precipitates is an important way to enhance the properties of transformation-induced plasticity (TRIP steels. In present work, two V-Ti microalloyed TRIP steels containing aluminum with different content were compared. The average size, size distribution and numbers of vanadium-titanium carbides in samples cold rolled, quenched after being held at 800°C and quenched after intercritical annealing at 800°C and being held at bainitic isothermal transformation temperature of 400°C were investigated by using the technique of carbon extraction replica, twin jet chemical polishing thinning and transmission electron microscopy. The carbides were identified to be (Ti,VC precipitates in steel A and VC in steel B respectively, precipitated mainly from ferrites grains. The average equivalent radius was 3~6nm. Comparison of the experimental results in A and B steel revealed low carbon diffusion rate caused by aluminum inhibited the coarsening of vanadium-titanium carbides. The experimental results also showed that VC carbides dissolution occurred during the intercritical annealing at 800°C.

  10. An acoustic eikonal equation for attenuating transversely isotropic media with a vertical symmetry axis

    KAUST Repository

    Hao, Qi

    2016-11-21

    Seismic-wave attenuation is an important component of describing wave propagation. Certain regions, such as gas clouds inside the earth, exert highly localized attenuation. In fact, the anisotropic nature of the earth induces anisotropic attenuation because the quasi P-wave dispersion effect should be profound along the symmetry direction. We have developed a 2D acoustic eikonal equation governing the complex-valued traveltime of quasi P-waves in attenuating, transversely isotropic media with a vertical-symmetry axis (VTI). This equation is derived under the assumption that the complex-valued traveltime of quasi P-waves in attenuating VTI media are independent of the S-wave velocity parameter υS0 in Thomsen\\'s notation and the S-wave attenuation coefficient AS0 in Zhu and Tsvankin\\'s notation. We combine perturbation theory and Shanks transform to develop practical approximations to the acoustic attenuating eikonal equation, capable of admitting an analytical description of the attenuation in homogeneous media. For a horizontal-attenuating VTI layer, we also derive the nonhyperbolic approximations for the real and imaginary parts of the complex-valued reflection traveltime. These equations reveal that (1) the quasi SV-wave velocity and the corresponding quasi SV-wave attenuation coefficient given as part of Thomsen-type notation barely affect the ray velocity and ray attenuation of quasi P-waves in attenuating VTI media; (2) combining the perturbation method and Shanks transform provides an accurate analytic eikonal solution for homogeneous attenuating VTI media; (3) for a horizontal attenuating VTI layer with weak attenuation, the real part of the complex-valued reflection traveltime may still be described by the existing nonhyperbolic approximations developed for nonattenuating VTI media, and the imaginary part of the complex-valued reflection traveltime still has the shape of nonhyperbolic curves. In addition, we have evaluated the possible extension of the

  11. Modeling broadband poroelastic propagation using an asymptotic approach

    Energy Technology Data Exchange (ETDEWEB)

    Vasco, Donald W.

    2009-05-01

    An asymptotic method, valid in the presence of smoothly-varying heterogeneity, is used to derive a semi-analytic solution to the equations for fluid and solid displacements in a poroelastic medium. The solution is defined along trajectories through the porous medium model, in the manner of ray theory. The lowest order expression in the asymptotic expansion provides an eikonal equation for the phase. There are three modes of propagation, two modes of longitudinal displacement and a single mode of transverse displacement. The two longitudinal modes define the Biot fast and slow waves which have very different propagation characteristics. In the limit of low frequency, the Biot slow wave propagates as a diffusive disturbance, in essence a transient pressure pulse. Conversely, at low frequencies the Biot fast wave and the transverse mode are modified elastic waves. At intermediate frequencies the wave characteristics of the longitudinal modes are mixed. A comparison of the asymptotic solution with analytic and numerical solutions shows reasonably good agreement for both homogeneous and heterogeneous Earth models.

  12. Media

    National Research Council Canada - National Science Library

    Emily Wexler

    2010-01-01

    .... Tradigital allows us to use online behaviour to track the effectiveness of online and offline media, not simply the correlation of TV airings with search activity, but also by employing a bevy...

  13. Microstructures and Continuous Cooling Transformation of CGHAZ in E36 Class V-N-Ti, V-Ti and Nb-Ti Shipbuilding Steels

    Science.gov (United States)

    Shi, Zhongran; Wang, Ruizhen; Wang, Qingfeng; Su, Hang; Chai, Feng; Yang, Caifu

    For the purpose of obtaining the optimal microstructures and mechanical properties of the CGHAZ under high input welding, continuous cooling transformation diagrams of the coarse grain heat-affected zone (CGHAZ) and the corresponding microstructures were investigated for a E36 class V-N-Ti, V-Ti, and Nb-Ti shipbuilding steels. The results indicated that the CGHAZ continuous transformation behaviors of Nb-Ti and V-Ti steel were similar, but the V-retard phenomenon was not as apparent as that of Nb. In addition, the cooling rate of ferrite transformation of V-Ti steel was higher than that of Nb-Ti steel. The nitrogen addition in the V-Ti steel enhanced the ferrite transformation, since that increasing the nitrogen could obtain fine (Ti, V)(C, N) particles and refine the original austenite size, which can promote the ferrite nucleation. The bainite transformation range of V-N-Ti steel was obviously lower than that of Nb-Ti, V-Ti steel at the t8/5≥100s.

  14. Finite difference modelling of dipole acoustic logs in a poroelastic formation with anisotropic permeability

    Science.gov (United States)

    He, Xiao; Hu, Hengshan; Wang, Xiuming

    2013-01-01

    Sedimentary rocks can exhibit strong permeability anisotropy due to layering, pre-stresses and the presence of aligned microcracks or fractures. In this paper, we develop a modified cylindrical finite-difference algorithm to simulate the borehole acoustic wavefield in a saturated poroelastic medium with transverse isotropy of permeability and tortuosity. A linear interpolation process is proposed to guarantee the leapfrog finite difference scheme for the generalized dynamic equations and Darcy's law for anisotropic porous media. First, the modified algorithm is validated by comparison against the analytical solution when the borehole axis is parallel to the symmetry axis of the formation. The same algorithm is then used to numerically model the dipole acoustic log in a borehole with its axis being arbitrarily deviated from the symmetry axis of transverse isotropy. The simulation results show that the amplitudes of flexural modes vary with the dipole orientation because the permeability tensor of the formation is dependent on the wellbore azimuth. It is revealed that the attenuation of the flexural wave increases approximately linearly with the radial permeability component in the direction of the transmitting dipole. Particularly, when the borehole axis is perpendicular to the symmetry axis of the formation, it is possible to estimate the anisotropy of permeability by evaluating attenuation of the flexural wave using a cross-dipole sonic logging tool according to the results of sensitivity analyses. Finally, the dipole sonic logs in a deviated borehole surrounded by a stratified porous formation are modelled using the proposed finite difference code. Numerical results show that the arrivals and amplitudes of transmitted flexural modes near the layer interface are sensitive to the wellbore inclination.

  15. Models for seismic wave propagation in periodically layered porous media

    NARCIS (Netherlands)

    Kudarova, A.; Van Dalen, K.N.; Drijkoningen, G.G.

    2014-01-01

    Several models are discussed for seismic wave propagation in periodically layered poroelastic media where layers represent mesoscopic-scale heterogeneities that are larger than the pore and grain sizes but smaller than the wavelength. The layers behave according to Biot’s theory. Wave propagation

  16. The impact of ventilation tubes in otitis media on the risk of cholesteatoma on a national level

    DEFF Research Database (Denmark)

    Djurhuus, Bjarki Ditlev; Christensen, Kaare; Skytthe, Axel

    2015-01-01

    OBJECTIVE: To estimate the impact of treatment with middle ear ventilation tube insertion (VTI) in children with otitis media (OM) on the risk of cholesteatoma on a national level. METHODS: Data were obtained from the Danish National Patient Register, the National Health Service Register...... the risk of STMEC1 by 54% (47-63%), while each additional year between two successive tube insertions increased the risk by 28% (15-43%). CONCLUSION: We found that prolonged OM requiring multiple VTIs was associated with an increased risk of STMEC1. Early age at first VTI and short time between two VTIs...... was associated with a lower risk of STMEC1. This may be the result of reduced time with negative middle ear pressure and OM. However, these findings may be susceptible to selection bias, as age at first VTI and time between VTIs, as well as the outcome variable, STMEC1, may all depend on the underlying...

  17. Eigenvalue Analysis of sound propagation characteristics in a circular duct lined with poroelastic foams

    Science.gov (United States)

    Son, Myung Seob; Lee, Seung Yeop; Kang, Yeon June

    2014-03-01

    An effective method for eigenvalue analysis of a circular duct lined with poroelastic foams is presented using axisymmetric finite element models based on Biot's theory and Helmholtz equation. Complex dispersion relations in a cylindrical foam-lined duct are successfully identified using an iterative Prony series method. It is shown that the numerical results obtained by the proposed method agree well with those obtained by measurements and direct forced response simulations. The influences of thickness and boundary conditions of the poroelastic foam on the sound propagation characteristics in a duct are also investigated. Furthermore, the damping effect due to viscosity of the foam on dispersion curves is discussed at a theoretical level.

  18. Azimuthal AVO signatures of fractured poroelastic sandstone layers

    Science.gov (United States)

    Guo, Zhiqi; Li, Xiang-Yang

    2017-10-01

    Azimuthal P-wave amplitude variation with offset (AVO) offers a method for the characterisation of a naturally fractured system in a reservoir. This information is important for the analysis of fluid flow during production of, for example, oil, petroleum and natural gas. This paper provides a modelling scheme by incorporating the squirt-flow model for the prediction of velocity dispersion and attenuation with azimuthal reflectivity method for the calculation of frequency-dependent seismic responses. Azimuthal AVO responses from a fractured poroelastic sandstone layer encased within shale are investigated based on the proposed method. Azimuthal reflections are a combination of the dynamic information including the contrast in anisotropic properties, anisotropic propagation and attenuation within the layer, as well as tuning and interferences. Modelling results indicate that seismic responses from the top of the sandstone layer are dominated by reflection coefficients, and show azimuthal variations at far offset which is consistent with conventional azimuthal AVO theory. Reflections from the base, however, demonstrate complex azimuthal variations due to anisotropic propagation and attenuation of transmission waves within the layer. Tuning and interferences further complicate the azimuthal AVO responses for thinner layer thickness. The AVO responses of top reflections show no azimuthal variations for lower fluid mobility, while those of base reflections show visible and stable azimuthal variations even at near and moderate offsets for different fluid mobility. Results also reveal that it would be practical to investigate wavetrains reflected from the fractured layers that are regarded as integrated units, especially for thinner layers where reflections from the top and base are indistinguishable. In addition, near-offset stacked amplitudes of the reflected wavetrains show detectable azimuthal variations, which may offer an initial look at fracture orientations before

  19. Poroelastic behaviors of the osteon: A comparison of two theoretical osteon models

    Science.gov (United States)

    Wu, Xiao-Gang; Chen, Wei-Yi

    2013-08-01

    In the paper, two theoretical poroelastic osteon models are presented to compare their poroelastic behaviors, one is the hollow osteon model (Haversian fluid is neglected) and the other is the osteon model with Haversian fluid considered. They both have the same two types of impermeable exterior boundary conditions, one is elastic restraint and the other is displacement constrained, which can be used for analyzing other experiments performed on similarly shaped poroelastic specimens. The obtained analytical pressure and velocity solutions demonstrate the effects of the loading factors and the material parameters, which may have a significant stimulus to the mechanotransduction of bone remodeling signals. Model comparisons indicate: (1) The Haversian fluid can enhance the whole osteonal fluid pressure and velocity fields. (2) In the hollow model, the key loading factor governing the poroelastic behavior of the osteon is strain rate, while in the model with Haversian fluid considered, the strain rate governs only the velocity. (3) The pressure amplitude is proportional to the loading frequency in the hollow model, while in the model with Haversian fluid considered, the loading frequency has little effect on the pressure amplitude.

  20. Effect of normal stress under an excitation in poroelastic flat slabs

    African Journals Online (AJOL)

    user

    Math.,1957, pp.465-481. M.Tajuddin, and G. Narayan Reddy, Effect of boundaries on the dynamic interaction of a liquid filled porous layer and a supporting continuum, Sadhana, Vol. 30, part 4, 2005, pp.527-535. M.Tajuddin and S.A. Shah, Circumferential waves of infinite poroelastic cylinders, Trans. ASME, J. Appl. Mech., ...

  1. A nonconforming finite element method for the Biot’s consolidation model in poroelasticity

    NARCIS (Netherlands)

    X. Hu (Xiaozhe); C. Rodrigo (Carmen); F.J. Gaspar Lorenz (Franscisco); C.W. Oosterlee (Cornelis)

    2017-01-01

    textabstractA stable finite element scheme that avoids pressure oscillations for a three-field Biot’s model in poroelasticity is considered. The involved variables are the displacements, fluid flux (Darcy velocity), and the pore pressure, and they are discretized by using the lowest possible

  2. Plane strain deformation of a multi-layered poroelastic half-space by ...

    Indian Academy of Sciences (India)

    The Biot linearized quasi-static theory of fluid-infiltrated porous materials is used to formu- late the problem of the two-dimensional plane strain deformation of a multi-layered poroelastic half-space by surface loads. The Fourier–Laplace transforms of the stresses, displacements, pore pressure and fluid flux in each ...

  3. Joint Estimation of Hydraulic and Poroelastic Parameters from a Pumping Test.

    Science.gov (United States)

    Berg, Steven J; Illman, Walter A; Mok, Chin Man W

    2015-01-01

    The coupling of hydraulic and poroelastic processes is critical in predicting processes involving the deformation of the geologic medium in response to fluid extraction or injection. Numerical models that consider the coupling of hydraulic and poroelastic processes require the knowledge of relevant parameters for both aquifer and aquitard units. In this study, we jointly estimated hydraulic and poroelastic parameters from pumping test data exhibiting "reverse water level fluctuations," known as the Noordbergum effect, in aquitards adjacent to a pumped aquifer. The joint estimation was performed by coupling BIOT2, a finite element, two-dimensional, axisymmetric, groundwater model that considers poroelastic effects with the parameter estimation code PEST. We first tested our approach using a synthetic data set with known parameters. Results of the synthetic case showed that for a simple layered system, it was possible to reproduce accurately both the hydraulic and poroelastic properties for each layer. We next applied the approach to pumping test data collected at the North Campus Research Site (NCRS) on the University of Waterloo (UW) campus. Based on the detailed knowledge of stratigraphy, a five-layer system was modeled. Parameter estimation was performed by: (1) matching drawdown data individually from each observation port and (2) matching drawdown data from all ports at a single well simultaneously. The estimated hydraulic parameters were compared to those obtained by other means at the site yielding good agreement. However, the estimated shear modulus was higher than the static shear modulus, but was within the range of dynamic shear modulus reported in the literature, potentially suggesting a loading rate effect. © 2014, National GroundWater Association.

  4. Investigation of fullerenol-induced changes in poroelasticity of human hepatocellular carcinoma by AFM-based creep tests.

    Science.gov (United States)

    Zhu, Xinyao; Cirovic, Srdjan; Shaheen, Aliah; Xu, Wei

    2017-12-01

    In this study, atomic force microscopy (AFM) is used to investigate the alterations of the poroelastic properties of hepatocellular carcinoma (SMMC-7721) cells treated with fullerenol. The SMMC-7721 cells were subject to AFM-based creep tests, and a corresponding poroelastic indentation model was used to determine the poroelastic parameters by curve fitting. Comparative analyses indicated that the both permeability and diffusion of fullerenol-treated cells increased significantly while their elastic modulus decreased by a small amount. From the change in the trend of the determined parameter, we verified the corresponding alternations of cytoskeleton (mainly filaments actin), which was reported by the previous study using confocal imaging method. Our investigation on SMMC-7721 cell reveals that the poroelastic properties could provide a better understanding how the cancer cells are affected by fullerenol or potentially other drugs which could find possible applications in drug efficacy test, cancer diagnosis and secure therapies.

  5. Geophysical models of heat and fluid flow in damageable poro-elastic continua

    Science.gov (United States)

    Roubíček, Tomáš

    2017-03-01

    A rather general model for fluid and heat transport in poro-elastic continua undergoing possibly also plastic-like deformation and damage is developed with the goal to cover various specific models of rock rheology used in geophysics of Earth's crust. Nonconvex free energy at small elastic strains, gradient theories (in particular the concept of second-grade nonsimple continua), and Biot poro-elastic model are employed, together with possible large displacement due to large plastic-like strains evolving during long time periods. Also the additive splitting is justified in stratified situations which are of interest in modelling of lithospheric crust faults. Thermodynamically based formulation includes entropy balance (in particular the Clausius-Duhem inequality) and an explicit global energy balance. It is further outlined that the energy balance can be used to ensure, under suitable data qualification, existence of a weak solution and stability and convergence of suitable approximation schemes at least in some particular situations.

  6. Numerical investigation of a seasonally loaded water reservoir: poroelastic and hydraulic response to loading and induced seismicty

    Science.gov (United States)

    Urpi, Luca; Catalli, Flaminia; Rinaldi, Antonio Pio; Buttinelli, Mauro; Improta, Luigi

    2016-04-01

    Water level reservoir affects the underlying crust stress state through the poroelastic response to the weight of the water volume stored and by the consequent fluid movement. The perturbation of crustal stress state has been associated in some cases with seismic events, with maximum magnitudes ranging from -1.0 and below up to magnitude 6.3, as recorded in the largest confirmed case of reservoir induced seismicity (RIS), that took place at the Konya reservoir in India. During a 13 months observation campaign at the Pertusillo water reservoir, located in Southern Italy, 2000 events have been recorded, with magnitude ranging from -0.2 up to 2.7. Statistical analysis and spatio-temporal seismicity patterns allows to identify two distinct RIS behaviors, as they have been reported in other RIS cases: seismicity associated with a short-term load effect and due to a longer term diffusion and movement of fluids. To discriminate between the undrained and the drained response and to correctly pinpoint the exact triggering mechanism, a forward numerical model (finite element) is presented here. The 3-dimensional model presented here allows including heterogeneous elastic and hydraulic parameters. The numerical solution for a homogeneous elastic model has been verified against the analytical solution. The short-term undrained response strongly depends on the elastic properties and can be amplified in a heterogeneous layered elastic media, especially for a media being stiffer with increasing depth. The long term response depends on the hydraulic properties and it can play a role even if the reservoir is hydraulically isolated from the underlying units. The calculated perturbation of stresses and pressure in space and time can be provided as an input to a statistical model to investigate the evolution of seismicity and the influence on the nearby fault system.

  7. Elastic waves along a cylindrical borehole in a poroelastic medium ...

    Indian Academy of Sciences (India)

    The propagation of elastic waves along a cylindrical borehole filled with/without liquid and embedded in an infinite porous medium saturated by two immiscible fluids has been studied. The theory of porous media saturated by two immiscible fluids developed by Tuncay and Corapcioglu (1997) is employed. Frequency ...

  8. An inverse-source problem for maximization of pore-fluid oscillation within poroelastic formations

    KAUST Repository

    Jeong, C.

    2016-07-04

    This paper discusses a mathematical and numerical modeling approach for identification of an unknown optimal loading time signal of a wave source, atop the ground surface, that can maximize the relative wave motion of a single-phase pore fluid within fluid-saturated porous permeable (poroelastic) rock formations, surrounded by non-permeable semi-infinite elastic solid rock formations, in a one-dimensional setting. The motivation stems from a set of field observations, following seismic events and vibrational tests, suggesting that shaking an oil reservoir is likely to improve oil production rates. This maximization problem is cast into an inverse-source problem, seeking an optimal loading signal that minimizes an objective functional – the reciprocal of kinetic energy in terms of relative pore-fluid wave motion within target poroelastic layers. We use the finite element method to obtain the solution of the governing wave physics of a multi-layered system, where the wave equations for the target poroelastic layers and the elastic wave equation for the surrounding non-permeable layers are coupled with each other. We use a partial-differential-equation-constrained-optimization framework (a state-adjoint-control problem approach) to tackle the minimization problem. The numerical results show that the numerical optimizer recovers optimal loading signals, whose dominant frequencies correspond to amplification frequencies, which can also be obtained by a frequency sweep, leading to larger amplitudes of relative pore-fluid wave motion within the target hydrocarbon formation than other signals.

  9. Grommets for otitis media with effusion in children with cleft palate: a systematic review.

    Science.gov (United States)

    Kuo, Chin-Lung; Tsao, Yuan-Heng; Cheng, Hao-Min; Lien, Chiang-Feng; Hsu, Chyong-Hsin; Huang, Chii-Yuan; Shiao, An-Suey

    2014-11-01

    No consensus has yet been reached with regard to the link between otitis media with effusion (OME), hearing loss, and language development in children with cleft palate. The objective of this study was to address the effectiveness of ventilation tube insertion (VTI) for OME in children with cleft palate. A dual review process was used to assess eligible studies drawn from PubMed, Medline via Ovid, Cumulative Index to Nursing and Allied Health Literature, Cochrane Library, and reference lists between 1948 and November 2013. Potentially relevant papers were selected according to the full text of the articles. Relevant data were extracted onto a data extraction sheet. Nine high- or moderate-quality cohort studies were included in this study. VTI was administered in 38% to 53% of the OME cases, and more severe cases appeared more likely to undergo VTI. Compared with conservative forms of management (eg, watchful waiting), VTI has been shown to be beneficial to the recovery of hearing in children with cleft palate and OME. A growing body of evidence demonstrates the benefits of VTI in the development of speech and language in children with cleft palate and OME. These children face a higher risk of complications than those undergoing conservative treatments, the most common of which are eardrum retraction and tympanosclerosis, with an incidence of ∼ 11% to 37%. This review provides evidence-based information related to the selection of treatment for OME in children with cleft palate. Additional randomized controlled trials are required to obtain bias-resistant evidence capable of reliably guiding treatment decisions. The conclusions in this review are based on underpowered cohort studies and very-low-strength evidence. Copyright © 2014 by the American Academy of Pediatrics.

  10. Hot cracking of welded joints of the 7CrMoVTiB 10-10 (T/P24) steel

    Science.gov (United States)

    Adamiec, J.

    2011-05-01

    Bainitic steel 7CrMoVTiB10-10 is one the newest steels for waterwalls of modern industrial boilers [1]. In Europe, attempts have been made to make butt welded joints of pipes made of this steel of the diameter up to 51 mm and thickness up to 8 mm. Many cracks have been observed in the welded joint, both during welding and transport and storage [2-4]. The reasons of cracking and the prevention methods have not been investigated. No comprehensive research is carried out in Europe in order to automate the welding process of the industrial boiler elements made of modern bainitic steel, such as 7CrMoVTiB10-10. There is no information about its overall, operative and local weldability, influence of heat treatment, as well as about resistance of the joints to cracking during welding and use. The paper presents experience of Energoinstal SA from development of technology and production of waterwalls of boilers made of the 7CrMoVTiB 10-10 steel on a multi-head automatic welder for submerged arc welding.

  11. A pseudospectral method for the simulation of 3-D ultrasonic and seismic waves in heterogeneous poroelastic borehole environments

    Science.gov (United States)

    Sidler, Rolf; Carcione, José M.; Holliger, Klaus

    2014-02-01

    We present a novel approach for the comprehensive, flexible and accurate simulation of poroelastic wave propagation in 3-D cylindrical coordinates. An important application of this method is the realistic modelling of complex seismic wave phenomena in fluid-filled boreholes, which represents a major, as of yet largely unresolved, problem in exploration geophysics. To this end, we consider a numerical mesh consisting of three concentric domains representing the borehole fluid in the centre followed by the mudcake and/or casing, and the surrounding porous formation. The spatial discretization is based on a Chebyshev expansion in the radial direction and Fourier expansions in the vertical and azimuthal directions as well as a Runge-Kutta integration scheme for the time evolution. Trigonometric interpolation and a domain decomposition method based on the method of characteristics are used to match the boundary conditions at the fluid/porous-solid and porous-solid/porous-solid interfaces as well as to reduce the number of gridpoints in the innermost domain for computational efficiency. We apply this novel modelling approach to the particularly challenging scenario of near-surface borehole environments. To this end, we compare 3-D heterogeneous and corresponding rotationally invariant simulations, assess the sensitivity of Stoneley waves to formation permeability in the presence of a casing and evaluate the effects of an excavation damage zone behind a casing on sonic log recordings. Our results indicate that only first arrival times of fast modes are reasonably well described by rotationally invariant approximations of 3-D heterogenous media. We also find that Stoneley waves are indeed remarkably sensitive to the average permeability behind a perforated PVC casing, and that the presence of an excavation damage zone behind a casing tends to dominate the overall signature of recorded seismograms.

  12. Rupture Propagation of the 2013 Mw7.7 Balochistan, Pakistan, Earthquake Affected by Poroelastic Stress Changes

    Science.gov (United States)

    He, J.; Wang, W.; Xiao, J.

    2015-12-01

    The 2013 Mw7.7 Balochistan, Pakistan, earthquake occurred on the curved Hoshab fault. This fault connects with the north-south trending Chaman strike-slip fault to northeast, and with the west-east trending Makran thrust fault system to southwest. Teleseismic waveform inversion, incorporated with coseismic ground surface deformation data, show that the rupture of this earthquake nucleated around northeast segment of the fault, and then propagated southwestward along the northwest dipping Hoshab fault about 200 km, with the maximum coseismic displacement, featured mainly by purely left-lateral strike-slip motion, about 10 meters. In context of the India-Asia collision frame, associating with the fault geometry around this region, the rupture propagation of this earthquake seems to not follow an optimal path along the fault segment, because after nucleation of this event the Hoshab fault on the southwest of hypocenter of this earthquake is clamped by elastic stress change. Here, we build a three-dimensional finite-element model to explore the evolution of both stress and pore-pressure during the rupturing process of this earthquake. In the model, the crustal deformation is treated as undrained poroelastic media as described by Biot's theory, and the instantaneous rupture process is specified with split-node technique. By testing a reasonable range of parameters, including the coefficient of friction, the undrained Poisson's ratio, the permeability of the fault zone and the bulk crust, numerical results have shown that after the nucleation of rupture of this earthquake around the northeast of the Hoshab fault, the positive change of normal stress (clamping the fault) on the fault plane is greatly reduced by the instantaneous increase of pore pressure (unclamping the fault). This process could result in the change of Coulomb failure stress resolved on the Hoshab fault to be hastened, explaining the possible mechanism for southwestward propagation of rupture of the Mw7

  13. A locally conservative stabilized continuous Galerkin finite element method for two-phase flow in poroelastic subsurfaces

    Science.gov (United States)

    Deng, Q.; Ginting, V.; McCaskill, B.; Torsu, P.

    2017-10-01

    We study the application of a stabilized continuous Galerkin finite element method (CGFEM) in the simulation of multiphase flow in poroelastic subsurfaces. The system involves a nonlinear coupling between the fluid pressure, subsurface's deformation, and the fluid phase saturation, and as such, we represent this coupling through an iterative procedure. Spatial discretization of the poroelastic system employs the standard linear finite element in combination with a numerical diffusion term to maintain stability of the algebraic system. Furthermore, direct calculation of the normal velocities from pressure and deformation does not entail a locally conservative field. To alleviate this drawback, we propose an element based post-processing technique through which local conservation can be established. The performance of the method is validated through several examples illustrating the convergence of the method, the effectivity of the stabilization term, and the ability to achieve locally conservative normal velocities. Finally, the efficacy of the method is demonstrated through simulations of realistic multiphase flow in poroelastic subsurfaces.

  14. Tendon exhibits complex poroelastic behavior at the nanoscale as revealed by high-frequency AFM-based rheology.

    Science.gov (United States)

    Connizzo, Brianne K; Grodzinsky, Alan J

    2017-03-21

    Tendons transmit load from muscle to bone by utilizing their unique static and viscoelastic tensile properties. These properties are highly dependent on the composition and structure of the tissue matrix, including the collagen I hierarchy, proteoglycans, and water. While the role of matrix constituents in the tensile response has been studied, their role in compression, particularly in matrix pressurization via regulation of fluid flow, is not well understood. Injured or diseased tendons and tendon regions that naturally experience compression are known to have alterations in glycosaminoglycan content, which could modulate fluid flow and ultimately mechanical function. While recent theoretical studies have predicted tendon mechanics using poroelastic theory, no experimental data have directly demonstrated such behavior. In this study, we use high-bandwidth AFM-based rheology to determine the dynamic response of tendons to compressive loading at the nanoscale and to determine the presence of poroelastic behavior. Tendons are found to have significant characteristic dynamic relaxation behavior occurring at both low and high frequencies. Classic poroelastic behavior is observed, although we hypothesize that the full dynamic response is caused by a combination of flow-dependent poroelasticity as well as flow-independent viscoelasticity. Tendons also demonstrate regional dependence in their dynamic response, particularly near the junction of tendon and bone, suggesting that the structural and compositional heterogeneity in tendon may be responsible for regional poroelastic behavior. Overall, these experiments provide the foundation for understanding fluid-flow-dependent poroelastic mechanics of tendon, and the methodology is valuable for assessing changes in tendon matrix compressive behavior at the nanoscale. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Fluid flow and coupled poroelastic response in low-permeability rocks

    Science.gov (United States)

    Hasanov, A.; Prasad, M.

    2015-12-01

    Hydraulic transport properties of reservoir rocks are traditionally defined as rock properties, responsiblefor the passage of fluids through the porous rock sample, as well as their storage. These properties arealso called permeability and storage capacity. The evaluation of both is an important part of any reservoircharacterization workflow. A vivid example of the importance of the transport properties is the bloomingbusiness of unconventional oil and gas production. Tight formations with ultra-low permeabilities and storagecapacities, which have never been perceived as reservoir rocks, today are actively exploited for oil and gas.This tremendous achievement in petroleum science and technology was only possible due to hydraulic frac-turing, which is essentially a process of enhancing permeability and storage capacity by creating a swarmof microcracks in the rock. The knowledge of hydraulic and poroelastic properties is also essential for proper simulations of diffusive pore fluidflow in petroleum reservoirs, as well as aquifers. This work is devoted to an integrated study of low-permeability rocks' hydraulic and poroe-lastic properties as measured with the oscillating pore pressure experiment. The oscillating pore pressuremethod is traditionally used to measure hydraulic transport properties. We modified the method and builtan experimental setup, capable of measuring all aforementioned rock properties simultaneously. The mea-surements were carried out for four sub-millidarcy rock samples at a range of oscillationfrequencies and effective stresses. An apparent frequency dependence of permeability was observed. Measured frequency dispersion of drained poroelastic propertiesindicates an intrinsically inelastic nature of the porous mineral rock frame. Standard Linear Model demon-strated the best fit to the experimental dispersion data. We established that hydraulically-measured storage capacitiesare in good agreement with elastically-derived ones. We also introduce a

  16. The Pawnee Sequence: Poroelastic Effects from Injection in Osage County, Oklahoma

    Science.gov (United States)

    Barbour, A. J.; Rubinstein, J. L.

    2016-12-01

    Aggregate multi-year records of wastewater injection in Oklahoma show that the strongest change in injection within 20 km of the 2016 M5.8 Pawnee strike-slip earthquake was in Osage County, where injection rates increased rapidly in late-2012 by nearly a factor of three above previous levels. After this increase, rates there declined steadily over two years to an average rate characteristic of all other injection wells in Pawnee and Noble Counties, remaining relatively constant until the beginning of the earthquake sequence. Here we test if poroelastic effects associated with this injection-rate transient can help explain the relative timing between peak injection rates and the beginning of the Pawnee sequence. Although the alternative hypothesis that regional-scale faults and fractures in critically stressed rock serve as fast-pathways for fluid diffusion cannot be ruled out, it appears to be difficult to reconcile based solely on injection data and space-time patterns for this seismic sequence. We simulate the cylindrically symmetric, transient strain and pore pressure fields for an injection-source time function emulating the injection history in a layered half-space in accordance with linear poroelasticity. In the simulation domain, injection occurs at depths of 1300 - 1900 m, into a homogeneous basal sedimentary reservoir representing the Arbuckle Group, overlying a semi-infinite layer representing granitic basement; we determined the hydraulic, elastic, and poroelastic properties of these layers from published literature. At the mainshock hypocenter, this numerical model predicts a delay between peak injection rates and pore pressure increase that is strongly dependent on hydraulic diffusivity; however, the duration is also controlled by the bulk elastic properties and the undrained Skempton's coefficient of the rock. Furthermore, because of fluid-strain coupling, pore pressures in the basement rock decrease during this delay period, which would tend to

  17. Aseismic and seismic slip induced by fluid injection from poroelastic and rate-state friction modeling

    Science.gov (United States)

    Liu, Y.; Deng, K.; Harrington, R. M.; Clerc, F.

    2016-12-01

    Solid matrix stress change and pore pressure diffusion caused by fluid injection has been postulated as key factors for inducing earthquakes and aseismic slip on pre-existing faults. In this study, we have developed a numerical model that simulates aseismic and seismic slip in a rate-and-state friction framework with poroelastic stress perturbations from multi-stage hydraulic fracturing scenarios. We apply the physics-based model to the 2013-2015 earthquake sequences near Fox Creek, Alberta, Canada, where three magnitude 4.5 earthquakes were potentially induced by nearby hydraulic fracturing activity. In particular, we use the relocated December 2013 seismicity sequence to approximate the fault orientation, and find the seismicity migration spatiotemporally correlate with the positive Coulomb stress changes calculated from the poroelastic model. When the poroelastic stress changes are introduced to the rate-state friction model, we find that slip on the fault evolves from aseismic to seismic in a manner similar to the onset of seismicity. For a 15-stage hydraulic fracturing that lasted for 10 days, modeled fault slip rate starts to accelerate after 3 days of fracking, and rapidly develops into a seismic event, which also temporally coincides with the onset of induced seismicity. The poroelastic stress perturbation and consequently fault slip rate continue to evolve and remain high for several weeks after hydraulic fracturing has stopped, which may explain the continued seismicity after shut-in. In a comparison numerical experiment, fault slip rate quickly decreases to the interseismic level when stress perturbations are instantaneously returned to zero at shut-in. Furthermore, when stress perturbations are removed just a few hours after the fault slip rate starts to accelerate (that is, hydraulic fracturing is shut down prematurely), only aseismic slip is observed in the model. Our preliminary results thus suggest the design of fracturing duration and flow

  18. Scanning anisotropy parameters in complex media

    KAUST Repository

    Alkhalifah, Tariq Ali

    2011-03-21

    Parameter estimation in an inhomogeneous anisotropic medium offers many challenges; chief among them is the trade-off between inhomogeneity and anisotropy. It is especially hard to estimate the anisotropy anellipticity parameter η in complex media. Using perturbation theory and Taylor’s series, I have expanded the solutions of the anisotropic eikonal equation for transversely isotropic (TI) media with a vertical symmetry axis (VTI) in terms of the independent parameter η from a generally inhomogeneous elliptically anisotropic medium background. This new VTI traveltime solution is based on a set of precomputed perturbations extracted from solving linear partial differential equations. The traveltimes obtained from these equations serve as the coefficients of a Taylor-type expansion of the total traveltime in terms of η. Shanks transform is used to predict the transient behavior of the expansion and improve its accuracy using fewer terms. A homogeneous medium simplification of the expansion provides classical nonhyperbolic moveout descriptions of the traveltime that are more accurate than other recently derived approximations. In addition, this formulation provides a tool to scan for anisotropic parameters in a generally inhomogeneous medium background. A Marmousi test demonstrates the accuracy of this approximation. For a tilted axis of symmetry, the equations are still applicable with a slightly more complicated framework because the vertical velocity and δ are not readily available from the data.

  19. Inverse problem in anisotropic poroelasticity: Drained constants from undrained ultrasound measurements

    Energy Technology Data Exchange (ETDEWEB)

    Berryman, J.G.; Nakagawa, S.

    2009-11-20

    Poroelastic analysis has traditionally focused on the relationship between dry or drained constants which are assumed known and the saturated or undrained constants which are assumed unknown. However, there are many applications in this field of study for which the main measurements can only be made on the saturated/undrained system, and then it is uncertain what the eects of the uids were on the system, since the drained constants remain a mystery. The work presented here shows how to deduce drained constants from undrained constants for anisotropic systems having symmetries ranging from isotropic to orthotropic. Laboratory ultrasound data are then inverted for the drained constants in three granular packings: one of glass beads, and two others for distinct types of more or less angular sand grain packings. Experiments were performed under uniaxial stress, which resulted in hexagonal (transversely isotropic) symmetry of the poroelastic response. One important conclusion from the general analysis is that the drained constants are uniquely related to the undrained constants, assuming that porosity, grain bulk modulus, and pore uid bulk modulus are already known. Since the resulting system of equations for all the drained constants is linear, measurement error in undrained constants also propagates linearly into the computed drained constants.

  20. A fully dynamic multi-compartmental poroelastic system: Application to aqueductal stenosis.

    Science.gov (United States)

    Chou, Dean; Vardakis, John C; Guo, Liwei; Tully, Brett J; Ventikos, Yiannis

    2016-07-26

    This study proposes the implementation of a fully dynamic four-network poroelastic model which is underpinned by multiple-network poroelastic theory (MPET), in order to account for the effects of varying stages of aqueductal stenosis and atresia during acute hydrocephalus. The innovation of the fully dynamic MPET implementation is that it avoids the commonplace assumption of quasi-steady behaviour; instead, it incorporates all transient terms in the casting of the equations and in the numerical solution of the resulting discrete system. It was observed that the application of mild stenosis allows for a constant value of amalgamated ventricular displacement in under 2.4h, whereas the application of a severe stenosis delays this settlement to approximately 10h. A completely blocked aqueduct does not show a clear sign of reaching a steady ventricular displacement after 24h. The increasing ventricular pressure (complemented with ventriculomegaly) during severe stenosis is causing the trans-parenchymal tissue region to respond, and this coping mechanism is most attenuated at the regions closest to the skull and the ventricles. After 9h, the parenchymal tissue shows to be coping well with the additional pressure burden, since both ventriculomegaly and ventricular CSF (cerebrospinal fluid) pressure show small increases between 9 and 24h. Localised swelling in the periventricular region could also be observed through CSF fluid content, whilst dilation results showed stretch and compression of cortical tissue adjacent to the ventricles and skull. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  1. Spring-damper equivalents of the fractional, poroelastic, and poroviscoelastic models for elastography.

    Science.gov (United States)

    Holm, Sverre

    2017-11-27

    In MR elastography, it is common to use an elastic model for the tissue's response in order to interpret the results properly. More complex models, such as viscoelastic, fractional viscoelastic, poroelastic, or poroviscoelastic ones, are also used. These models appear at first sight to be very different, but here it is shown that they may all be expressed in terms of elementary viscoelastic models. For a medium expressed with fractional models, many elementary spring-damper combinations are added, each of them weighted according to a long-tailed distribution of time constants or relaxation frequencies. This may open up a more physical interpretation of fractional models. The shear-wave component of the poroelastic model is shown to be modeled exactly by a three-component Zener model. The extended poroviscoelastic model is found to be equivalent to what is called a non-standard four-parameter model. Accordingly, the large number of parameters in the porous models can be reduced to the same number as in their viscoelastic equivalents. While the individual displacements from the solid and fluid parts cannot be measured individually, the main use of the poro(visco)elastic models is therefore as a physics-based method for determining parameters in a viscoelastic model. © 2017 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.

  2. Universal poroelastic mechanism for hydraulic signals in biomimetic and natural branches.

    Science.gov (United States)

    Louf, J-F; Guéna, G; Badel, E; Forterre, Y

    2017-10-17

    Plants constantly undergo external mechanical loads such as wind or touch and respond to these stimuli by acclimating their growth processes. A fascinating feature of this mechanical-induced growth response is that it can occur rapidly and at long distance from the initial site of stimulation, suggesting the existence of a fast signal that propagates across the whole plant. The nature and origin of the signal is still not understood, but it has been recently suggested that it could be purely mechanical and originate from the coupling between the local deformation of the tissues (bending) and the water pressure in the plant vascular system. Here, we address the physical origin of this hydromechanical coupling using a biomimetic strategy. We designed soft artificial branches perforated with longitudinal liquid-filled channels that mimic the basic features of natural stems and branches. In response to bending, a strong overpressure is generated in the channels that varies quadratically with the bending curvature. A model based on a mechanism analogous to the ovalization of hollow tubes enables us to predict quantitatively this nonlinear poroelastic response and identify the key physical parameters that control the generation of the pressure pulse. Further experiments conducted on natural tree branches reveal the same phenomenology. Once rescaled by the model prediction, both the biomimetic and natural branches fall on the same master curve, enlightening the universality of our poroelastic mechanism for the generation of hydraulic signals in plants.

  3. Wave energy focusing to subsurface poroelastic formations to promote oil mobilization

    KAUST Repository

    Karve, P. M.

    2015-04-22

    We discuss an inverse source formulation aimed at focusing wave energy produced by ground surface sources to target subsurface poroelastic formations. The intent of the focusing is to facilitate or enhance the mobility of oil entrapped within the target formation. The underlying forward wave propagation problem is cast in two spatial dimensions for a heterogeneous poroelastic target embedded within a heterogeneous elastic semi-infinite host. The semi-infiniteness of the elastic host is simulated by augmenting the (finite) computational domain with a buffer of perfectly matched layers. The inverse source algorithm is based on a systematic framework of partial-differential-equation-constrained optimization. It is demonstrated, via numerical experiments, that the algorithm is capable of converging to the spatial and temporal characteristics of surface loads that maximize energy delivery to the target formation. Consequently, the methodology is well-suited for designing field implementations that could meet a desired oil mobility threshold. Even though the methodology, and the results presented herein are in two dimensions, extensions to three dimensions are straightforward.

  4. Vibroacoustic study on a multilayered functionally graded cylindrical shell with poroelastic core and bonded-unbonded configuration

    Science.gov (United States)

    Daneshjou, K.; Talebitooti, R.; Kornokar, M.

    2017-04-01

    This paper presents an analytical solution for sound transmission through a multilayered cylindrical shell with bonded-unbonded (BU) configuration. The multilayered cylindrical shell, which is composed of an outer layer of functionally graded material (FGM) and an inner isotropic layer with a poroelastic core and an air gap, is assumed to be infinitely long and is subjected to a plane wave on its external sidewall. To describe the poroelastic core, the extended full method (EFM) is applied based on Biot's theory. Contrary to previous methods, the EFM completely models the poroelastic cylindrical shell in three dimensions. In addition, the motions of both FGM and isotropic shells are described with the first order shear deformation theory (FSDT). Unlike the simplified method, the EFM does not need to identify the frequency ranges where one of the airborne or frame waves is dominant in BU configuration. In fact, utilizing the EFM for BU configuration permits obtaining the sound transmission loss (TL) irrespective of the dominant wave, which significantly reduces the computational work. Moreover, comparing with the previous models, the EFM provides more accurate results as it does not ignore any term in the modeling. Furthermore, the advantages of the BU-FGM shell in enhancing the TL are demonstrated with respect to the BB-isotropic configuration. It is shown that presence of the FGM in addition to the poroelastic material in a structure yields thermal insulation and improves soundproofing characteristics in a broadband frequency range.

  5. A minimal model for flow control on an aerofoil using a poro-elastic coating

    Science.gov (United States)

    Venkataraman, Divya; Bottaro, Alessandro; Govindarajan, Rama

    2014-05-01

    A minimal model is obtained for vortex-shedding from an aerofoil with a porous coating of flow-compliant feather-like actuators, in order to better understand this passive way to achieve flow control. This model is realized by linearly coupling a minimal-order model for vortex-shedding from the same aerofoil without any such coating with an equation for the poro-elastic coating, here modelled as a linear damped oscillator. The various coefficients in this model, derived using perturbation techniques, aid in our understanding of the physics of this fluid-structure interaction problem. The minimal model for a coated aerofoil indicates the presence of distinct regimes that are dependent on the flow and coating characteristics. The models and the parametric studies performed provide insight into the selection of optimal coating parameters, to enable flow control at low Reynolds numbers.

  6. An axisymmetric and fully 3D poroelastic model for the evolution of hydrocephalus.

    Science.gov (United States)

    Wirth, Benedikt; Sobey, Ian

    2006-12-01

    We formulate in general terms the equations for axisymmetric and fully 3D models of a hydrocephalic brain. The model is developed using small strain poroelasticity that includes non-linear permeability. The axisymmetric model is solved for four ventricle shapes, an ellipsoid, a 'peanut' shape, a 'cross' shape and a 'bone' shape. The distribution of fluid pressure, velocity and content in the deformed parenchyma for a blocked aqueduct provides new qualitative insight into hydrocepahlus. Some observations are offered for two forms of cerebrospinal fluid flow abnormality, normal pressure hydrocephalus and idiopathic intracranial hypertension. The model is extended to include a gravitational term in the governing equations and the effect of hydrostatic pressure variation is considered. Results of a fully 3D simulations are described for two horn-like lateral ventricles and one case with two lateral ventricles and a third ventricle.

  7. Viscoelastic and poroelastic effects in the wetting dynamics of soft gels by liquids

    Science.gov (United States)

    Limat, Laurent; Dervaux, Julien; Roche, Matthieu; Zhao, Menghua; Narita, Tetsuharu; Lequeux, Francois

    2017-11-01

    We have developed experiments and modeling of elastowetting dynamics on soft gels. First, wetting is very sensitive to the thickness of the gel, when deposited on a rigid basis. We reconsidered Long et al. approach, and extended it to finite depth. This yields a new scaling law, at low thickness, for dynamic contact angle, in very good agreement with experiment but not consistent with recent approachs assuming Neuman triangle to hold even in the dynamics. In a second step, we examined solvent migration in the bulk of the gel, and showed that poroelasticity is an essential ingredient to understand old unsolved issues (hysteresis on elastomers by Extrand and Kumagai), as well as recent puzzling measurements (long life footprints left by drops). Our calculations lead to ridges at the contact lines evolving logarithmically with time, with a very strong infuence on wetting properties of soft materials, and with possible applications to biophysics.

  8. Three-Dimensional poroelastic effects during hydraulic fracturing in permeable rocks

    DEFF Research Database (Denmark)

    Salimzadeh, Saeed; Paluszny, Adriana; Zimmerman, Robert W.

    2017-01-01

    -dominated, and leakoff-dominated regimes. However, for intermediate regimes, these analytical solutions cannot be used to predict the key hydraulic fracturing variables, i.e. injection pressure, fracture aperture, and length. For leakoff-dominated cases in permeable rocks, the asymptotic solutions fail to accurately...... predict the lower-bound for fracture radius and apertures, and the upper-bound for fracture pressure. This is due to the poroelastic effects in the dilated rock matrix, as well as due to the multi-dimensional flow within matrix, which in many simulation codes is idealised as being one-dimensional, normal......A fully coupled three-dimensional finite-element model for hydraulic fractures in permeable rocks is presented, and used to investigate the ranges of applicability of the classical analytical solutions that are known to be valid in limiting cases. This model simultaneously accounts for fluid flow...

  9. Finite element simulations of interactions between multiple hydraulic fractures in a poroelastic rock

    DEFF Research Database (Denmark)

    Salimzadeh, Saeed; Usui, Tomoya; Paluszny, Adriana

    2017-01-01

    -dominated, and leakoff-dominated regimes. However, for intermediate regimes, these analytical solutions cannot be used to predict the key hydraulic fracturing variables, i.e. injection pressure, fracture aperture, and length. For leakoff-dominated cases in permeable rocks, the asymptotic solutions fail to accurately...... predict the lower-bound for fracture radius and apertures, and the upper-bound for fracture pressure. This is due to the poroelastic effects in the dilated rock matrix, as well as due to the multi-dimensional flow within matrix, which in many simulation codes is idealised as being one-dimensional, normal......A fully coupled three-dimensional finite-element model for hydraulic fractures in permeable rocks is presented, and used to investigate the ranges of applicability of the classical analytical solutions that are known to be valid in limiting cases. This model simultaneously accounts for fluid flow...

  10. Tidal triggering of earthquakes suggests poroelastic behavior on the San Andreas Fault

    Science.gov (United States)

    Delorey, Andrew; Van Der Elst, Nicholas; Johnson, Paul

    2017-01-01

    Tidal triggering of earthquakes is hypothesized to provide quantitative information regarding the fault's stress state, poroelastic properties, and may be significant for our understanding of seismic hazard. To date, studies of regional or global earthquake catalogs have had only modest successes in identifying tidal triggering. We posit that the smallest events that may provide additional evidence of triggering go unidentified and thus we developed a technique to improve the identification of very small magnitude events. We identify events applying a method known as inter-station seismic coherence where we prioritize detection and discrimination over characterization. Here we show tidal triggering of earthquakes on the San Andreas Fault. We find the complex interaction of semi-diurnal and fortnightly tidal periods exposes both stress threshold and critical state behavior. Our findings reveal earthquake nucleation processes and pore pressure conditions – properties of faults that are difficult to measure, yet extremely important for characterizing earthquake physics and seismic hazards.

  11. Global optimisation methods for poroelastic material characterisation using a clamped sample in a Kundt tube setup

    Science.gov (United States)

    Vanhuyse, Johan; Deckers, Elke; Jonckheere, Stijn; Pluymers, Bert; Desmet, Wim

    2016-02-01

    The Biot theory is commonly used for the simulation of the vibro-acoustic behaviour of poroelastic materials. However, it relies on a number of material parameters. These can be hard to characterize and require dedicated measurement setups, yielding a time-consuming and costly characterisation. This paper presents a characterisation method which is able to identify all material parameters using only an impedance tube. The method relies on the assumption that the sample is clamped within the tube, that the shear wave is excited and that the acoustic field is no longer one-dimensional. This paper numerically shows the potential of the developed method. It therefore performs a sensitivity analysis of the quantification parameters, i.e. reflection coefficients and relative pressures, and a parameter estimation using global optimisation methods. A 3-step procedure is developed and validated. It is shown that even in the presence of numerically simulated noise this procedure leads to a robust parameter estimation.

  12. DOMAIN DECOMPOSITION FOR POROELASTICITY AND ELASTICITY WITH DG JUMPS AND MORTARS

    KAUST Repository

    GIRAULT, V.

    2011-01-01

    We couple a time-dependent poroelastic model in a region with an elastic model in adjacent regions. We discretize each model independently on non-matching grids and we realize a domain decomposition on the interface between the regions by introducing DG jumps and mortars. The unknowns are condensed on the interface, so that at each time step, the computation in each subdomain can be performed in parallel. In addition, by extrapolating the displacement, we present an algorithm where the computations of the pressure and displacement are decoupled. We show that the matrix of the interface problem is positive definite and establish error estimates for this scheme. © 2011 World Scientific Publishing Company.

  13. Fluid and solid mechanics in a poroelastic network induced by ultrasound.

    Science.gov (United States)

    Wang, Peng; Olbricht, William L

    2011-01-04

    We made a theoretical analysis on the fluid and solid mechanics in a poroelastic medium induced by low-power ultrasound. Using a perturbative approach, we were able to linearize the governing equations and obtain analytical solutions. We found that ultrasound could propagate in the medium as a mechanical wave, but would dissipate due to frictional forces between the fluid and the solid phase. The amplitude of the wave depends on the ultrasonic power input. We applied this model to the problem of drug delivery to soft biological tissues by low-power ultrasound and proposed a mechanism for enhanced drug penetration. We have also found the coexistence of two acoustic waves under certain circumstances and pointed out the importance of very accurate experimental determination of the high-frequency properties of brain tissue. Copyright © 2010 Elsevier Ltd. All rights reserved.

  14. A discontinuous finite element approach to cracking in coupled poro-elastic fluid flow models

    Science.gov (United States)

    Wilson, C. R.; Spiegelman, M. W.; Evans, O.; Ulven, O. I.; Sun, W.

    2016-12-01

    Reaction-driven cracking is a coupled process whereby fluid-induced reactions drive large volume changes in the host rock which produce stresses leading to crack propagation and failure. This in turn generates new surface area and fluid-flow pathways for subsequent reaction in a potentially self-sustaining system. This mechanism has has been proposed for the pervasive serpentinization and carbonation of peridotite, as well as applications to mineral carbon sequestration and hydrocarbon extraction. The key computational issue in this problem is implementing algorithms that adequately model the formation of discrete fractures. Here we present models using a discontinuous finite element method for modeling fracture formation (Radovitsky et al., 2011). Cracks are introduced along facets of the mesh by the relaxation of penalty parameters once a failure criterion is met. It is fully described in the weak form of the equations, requiring no modification of the underlying mesh structure and allowing fluid properties to be easily adjusted along cracked facets. To develop and test the method, we start by implementing the algorithm for the simplified Biot equations for poro-elasticity using the finite element model assembler TerraFERMA. We consider hydro-fracking around a borehole (Grassl et al., 2015), where elevated fluid pressure in the poro-elastic solid causes it to fail radially in tension. We investigate the effects of varying the Biot coefficient and adjusting the fluid transport properties in the vicinity of the crack and compare our results to related dual-graph models (Ulven & Sun, submitted). We discuss issues arising from this method, including the formation of null spaces and appropriate preconditioning and solution strategies. Initial results suggest that this method provides a promising way to incorporate cracking into our reactive fluid flow models and future work aims to integrate the mechanical and chemical aspects of this process.

  15. Working towards a numerical solver for seismic wave propagation in unsaturated porous media

    Science.gov (United States)

    Boxberg, Marc S.; Friederich, Wolfgang

    2017-04-01

    Modeling the propagation of seismic waves in porous media gets more and more popular in the seismological community. However, it is still a challenging task in the field of computational seismology. Nevertheless, it is important to account for the fluid content of, e.g., reservoir rocks or soils, and the interaction between the fluid and the rock or between different immiscible fluids to accurately describe seismic wave propagation through such porous media. Often, numerical models are based on the elastic wave equation and some might include artificially introduced attenuation. This simplifies the computation, because it only approximates the physics behind that problem. However, the results are also simplified and could miss phenomena and lack accuracy in some applications. We present a numerical solver for wave propagation in porous media saturated by two immiscible fluids. It is based on Biot's theory of poroelasticity and accounts for macroscopic flow that occurs on the same scale as the wavelength of the seismic waves. Fluid flow is described by a Darcy type flow law and interactions between the fluids by means of capillary pressure curve models. In addition, consistent boundary conditions on interfaces between poroelastic media and elastic or acoustic media are derived from this poroelastic theory itself. The poroelastic solver is integrated into the larger software package NEXD that uses the nodal discontinuous Galerkin method to solve wave equations in 1D, 2D, and 3D on a mesh of linear (1D), triangular (2D), or tetrahedral (3D) elements. Triangular and tetrahedral elements have great advantages as soon as the model has a complex structure, like it is often the case for geologic models. We illustrate the capabilities of the codes by numerical examples. This work can be applied to various scientific questions in, e.g., exploration and monitoring of hydrocarbon or geothermal reservoirs as well as CO2 storage sites.

  16. Analysis of the in situ stress contrast impact on a planar hydraulic fracture propagation using the fully coupled poroelastic model

    Science.gov (United States)

    Baykin, A. N.; Golovin, S. V.

    2017-10-01

    In this paper, we use a fully coupled model for 3D planar fracture propagation within a poroelastic reservoir in order to analysis the non-symmetry of the fracture as it develops in a 3-layer reservoir with different compressive stresses in each layer. We demonstrate that the fracture predominantly develops in the layer with the lower compressive stress until it gets arrested due to the equality of the total leakoff to the volume of pumped fluid.

  17. Axisymmetric deformation of a poroelastic layer overlying an elastic half-space due to surface loading

    Science.gov (United States)

    Rani, Sunita; Rani, Sunita

    2017-11-01

    The axisymmetric deformation of a homogeneous, isotropic, poroelastic layer of uniform thickness overlying a homogeneous, isotropic, elastic half-space due to surface loads has been obtained. The fluid and the solid constituents of the porous layer are compressible and the permeability in vertical direction is different from its permeability in horizontal direction. The displacements and pore-pressure are taken as basic state variables. An analytical solution for the pore-pressure, displacements and stresses has been obtained using the Laplace-Hankel transform technique. The case of normal disc loading is discussed in detail. Diffusion of pore-pressure is obtained in the space-time domain. The Laplace inversion is evaluated using the fixed Talbot algorithm and the Hankel inversion using the extended Simpson's rule. Two different models of the Earth have been considered: continental crust model and oceanic crust model. For continental crust model, the layer is assumed to be of Westerly Granite and for the oceanic crust model of Hanford Basalt. The effect of the compressibilities of the fluid as well as solid constituents and anisotropy in permeability has been studied on the diffusion of pore-pressure. Contour maps have been plotted for the diffusion of pore-pressure for both models. It is observed that the pore-pressure changes to compression for the continental crust model with time, which is not true for the oceanic crust.

  18. A method of fundamental solutions in poroelasticity to model the stress field in geothermal reservoirs

    CERN Document Server

    Augustin, Matthias Albert

    2015-01-01

    This monograph focuses on the numerical methods needed in the context of developing a reliable simulation tool to promote the use of renewable energy. One very promising source of energy is the heat stored in the Earth’s crust, which is harnessed by so-called geothermal facilities. Scientists from fields like geology, geo-engineering, geophysics and especially geomathematics are called upon to help make geothermics a reliable and safe energy production method. One of the challenges they face involves modeling the mechanical stresses at work in a reservoir. The aim of this thesis is to develop a numerical solution scheme by means of which the fluid pressure and rock stresses in a geothermal reservoir can be determined prior to well drilling and during production. For this purpose, the method should (i) include poroelastic effects, (ii) provide a means of including thermoelastic effects, (iii) be inexpensive in terms of memory and computational power, and (iv) be flexible with regard to the locations of data ...

  19. A poroelastic model coupled to a fluid network with applications in lung modelling.

    Science.gov (United States)

    Berger, Lorenz; Bordas, Rafel; Burrowes, Kelly; Grau, Vicente; Tavener, Simon; Kay, David

    2016-01-01

    We develop a lung ventilation model based on a continuum poroelastic representation of lung parenchyma that is strongly coupled to a pipe network representation of the airway tree. The continuous system of equations is discretized using a low-order stabilised finite element method. The framework is applied to a realistic lung anatomical model derived from computed tomography data and an artificially generated airway tree to model the conducting airway region. Numerical simulations produce physiologically realistic solutions and demonstrate the effect of airway constriction and reduced tissue elasticity on ventilation, tissue stress and alveolar pressure distribution. The key advantage of the model is the ability to provide insight into the mutual dependence between ventilation and deformation. This is essential when studying lung diseases, such as chronic obstructive pulmonary disease and pulmonary fibrosis. Thus the model can be used to form a better understanding of integrated lung mechanics in both the healthy and diseased states. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  20. Poroelastic theory of consolidation in unsaturated soils incorporating gravitational body forces

    Science.gov (United States)

    Lo, Wei-Cheng; Chao, Nan-Chieh; Chen, Chu-Hui; Lee, Jhe-Wei

    2017-08-01

    The generalization of the poroelasticity theory of consolidation in unsaturated soils to well represent gravitational body forces is presented in the current study. Three partial differential equations featuring the displacement vector of the solid phase, along with the excess pore water and air pressures as dependent variables are derived, with coupling that occurs in the first-order temporal- and spatial- derivative terms. The former arises from viscous drag between solid and fluid, whereas the latter is attributed to the presence of gravity. Given the physically-consistent initial and boundary conditions, these coupled equations are numerically solved under uniaxial strain as a representative example. Our results reveal that variations in the excess pore water pressure due to the existence of gravitational forces increase with soil depth, but these variations are not significant if the soil layer is not sufficiently long. A dimensionless parameter is defined theoretically to quantify the impact of those forces on the final total settlement. This impact is shown to become greater as the soil layer is less stiff and has more length, and bears an inversely-proportional trend with initial water saturation.

  1. Finite frequency traveltime sensitivity kernels for acoustic anisotropic media: Angle dependent bananas

    KAUST Repository

    Djebbi, Ramzi

    2013-08-19

    Anisotropy is an inherent character of the Earth subsurface. It should be considered for modeling and inversion. The acoustic VTI wave equation approximates the wave behavior in anisotropic media, and especially it\\'s kinematic characteristics. To analyze which parts of the model would affect the traveltime for anisotropic traveltime inversion methods, especially for wave equation tomography (WET), we drive the sensitivity kernels for anisotropic media using the VTI acoustic wave equation. A Born scattering approximation is first derived using the Fourier domain acoustic wave equation as a function of perturbations in three anisotropy parameters. Using the instantaneous traveltime, which unwraps the phase, we compute the kernels. These kernels resemble those for isotropic media, with the η kernel directionally dependent. They also have a maximum sensitivity along the geometrical ray, which is more realistic compared to the cross-correlation based kernels. Focusing on diving waves, which is used more often, especially recently in waveform inversion, we show sensitivity kernels in anisotropic media for this case.

  2. First-arrival traveltime computation for quasi-P waves in 2D transversely isotropic media using Fermat’s principle-based fast marching

    Science.gov (United States)

    Hu, Jiangtao; Cao, Junxing; Wang, Huazhong; Wang, Xingjian; Jiang, Xudong

    2017-12-01

    First-arrival traveltime computation for quasi-P waves in transversely isotropic (TI) media is the key component of tomography and depth migration. It is appealing to use the fast marching method in isotropic media as it efficiently computes traveltime along an expanding wavefront. It uses the finite difference method to solve the eikonal equation. However, applying the fast marching method in anisotropic media faces challenges because the anisotropy introduces additional nonlinearity in the eikonal equation and solving this nonlinear eikonal equation with the finite difference method is challenging. To address this problem, we present a Fermat’s principle-based fast marching method to compute traveltime in two-dimensional TI media. This method is applicable in both vertical and tilted TI (VTI and TTI) media. It computes traveltime along an expanding wavefront using Fermat’s principle instead of the eikonal equation. Thus, it does not suffer from the nonlinearity of the eikonal equation in TI media. To compute traveltime using Fermat’s principle, the explicit expression of group velocity in TI media is required to describe the ray propagation. The moveout approximation is adopted to obtain the explicit expression of group velocity. Numerical examples on both VTI and TTI models show that the traveltime contour obtained by the proposed method matches well with the wavefront from the wave equation. This shows that the proposed method could be used in depth migration and tomography.

  3. Combination of poroelasticity theory and constant strain rate test in modelling land subsidence due to groundwater extraction

    Science.gov (United States)

    Pham, Tien Hung; Rühaak, Wolfram; Sass, Ingo

    2017-04-01

    Extensive groundwater extraction leads to a drawdown of the ground water table. Consequently, soil effective stress increases and can cause land subsidence. Analysis of land subsidence generally requires a numerical model based on poroelasticity theory, which was first proposed by Biot (1941). In the review of regional land subsidence accompanying groundwater extraction, Galloway and Burbey (2011) stated that more research and application is needed in coupling of stress-dependent land subsidence process. In geotechnical field, the constant rate of strain tests (CRS) was first introduced in 1969 (Smith and Wahls 1969) and was standardized in 1982 through the designation D4186-82 by American Society for Testing and Materials. From the reading values of CRS tests, the stress-dependent parameters of poroelasticity model can be calculated. So far, there is no research to link poroelasticity theory with CRS tests in modelling land subsidence due to groundwater extraction. One dimensional CRS tests using conventional compression cell and three dimension CRS tests using Rowe cell were performed. The tests were also modelled by using finite element method with mixed elements. Back analysis technique is used to find the suitable values of hydraulic conductivity and bulk modulus that depend on the stress or void ratio. Finally, the obtained results are used in land subsidence models. Biot, M. A. (1941). "General theory of three-dimensional consolidation." Journal of applied physics 12(2): 155-164. Galloway, D. L. and T. J. Burbey (2011). "Review: Regional land subsidence accompanying groundwater extraction." Hydrogeology Journal 19(8): 1459-1486. Smith, R. E. and H. E. Wahls (1969). "Consolidation under constant rates of strain." Journal of Soil Mechanics & Foundations Div.

  4. Analysis of Dynamic Fracture Compliance Based on Poroelastic Theory. Part I: Model Formulation and Analytical Expressions

    Science.gov (United States)

    Wang, Ding; Qu, Shou-Li; Ding, Ping-Bo; Zhao, Qun

    2017-05-01

    The presence of bedding-parallel fractures at any scale in a rock will considerably add to its compliance and elastic anisotropy. Those properties will be more significantly affected when there is a relatively high degree of connectivity between the fractures and the corresponding interconnected pores. This contribution uses linear poroelasticity to reveal the characteristics of the full frequency-dependent compliance of an infinitely extended fracture model assuming the periodicity of the fractured structures. The fracture compliance tensor is complex-valued due to the wave-induced fluid flow between fractures and pores. The interaction between the adjacent fractures is considered under fluid mass conservation throughout the whole pore space. The quantitative effects of fracture (volume) density (the ratio between fracture thickness and spacing) and host rock porosity are analyzed by the diffusion equation for a relatively low-frequency band. The model in this paper is equivalent to the classical dry linear slip model when the bulk modulus of fluid in the fractures tends to zero. For the liquid-filled case, the model becomes the anisotropic Gassmann's model and sealed saturated linear slip model at the low-frequency and high-frequency limits, respectively. Using the dynamic compliance definition, we can effectively distinguish the saturating fluids in the fractures with the same order magnitude of bulk modulus (e.g., water and oil) using the compliance ratio method. Additionally, the modified dynamic model can be simplified as acceptable empirical formulas if the strain on the fractures induced by the incoming waves is small enough.

  5. The azimuth-dependent offset-midpoint traveltime pyramid in 3D HTI media

    KAUST Repository

    Hao, Qi

    2013-09-22

    Analytical representation of offset-midpoint traveltime equation is very important for pre-stack Kirchhoff migration and velocity inversion in anisotropic media. For VTI media, the offset-midpoint traveltime resembles the shape of Cheop\\'s pyramid. In this study, we extend the offset-midpoint traveltime pyramid to the case of 3D HTI media. We employ the stationary phase method to derive the analytical representation of traveltime equation, and then use Shanks transformation to improve the accuracy of horizontal and vertical slownesses. The traveltime pyramid is derived in both the depth- and time-domain. Numerical examples indicate that the azimuthal characteristics of both the traveltime pyramid and the migration isochrones are very obvious in HTI media due to the effect of anisotropy.

  6. A meta-model analysis of a finite element simulation for defining poroelastic properties of intervertebral discs.

    Science.gov (United States)

    Nikkhoo, Mohammad; Hsu, Yu-Chun; Haghpanahi, Mohammad; Parnianpour, Mohamad; Wang, Jaw-Lin

    2013-06-01

    Finite element analysis is an effective tool to evaluate the material properties of living tissue. For an interactive optimization procedure, the finite element analysis usually needs many simulations to reach a reasonable solution. The meta-model analysis of finite element simulation can be used to reduce the computation of a structure with complex geometry or a material with composite constitutive equations. The intervertebral disc is a complex, heterogeneous, and hydrated porous structure. A poroelastic finite element model can be used to observe the fluid transferring, pressure deviation, and other properties within the disc. Defining reasonable poroelastic material properties of the anulus fibrosus and nucleus pulposus is critical for the quality of the simulation. We developed a material property updating protocol, which is basically a fitting algorithm consisted of finite element simulations and a quadratic response surface regression. This protocol was used to find the material properties, such as the hydraulic permeability, elastic modulus, and Poisson's ratio, of intact and degenerated porcine discs. The results showed that the in vitro disc experimental deformations were well fitted with limited finite element simulations and a quadratic response surface regression. The comparison of material properties of intact and degenerated discs showed that the hydraulic permeability significantly decreased but Poisson's ratio significantly increased for the degenerated discs. This study shows that the developed protocol is efficient and effective in defining material properties of a complex structure such as the intervertebral disc.

  7. Culturable Heavy Metal-Resistant and Plant Growth Promoting Bacteria in V-Ti Magnetite Mine Tailing Soil from Panzhihua, China

    Science.gov (United States)

    Zhang, Chu; Liu, Huiying; Liu, Jin; Zheng, Wenwen; Kang, Xia; Leng, Xuejun; Zhao, Ke; Gu, Yunfu; Zhang, Xiaoping; Xiang, Quanju; Chen, Qiang

    2014-01-01

    To provide a basis for using indigenous bacteria for bioremediation of heavy metal contaminated soil, the heavy metal resistance and plant growth-promoting activity of 136 isolates from V-Ti magnetite mine tailing soil were systematically analyzed. Among the 13 identified bacterial genera, the most abundant genus was Bacillus (79 isolates) out of which 32 represented B. subtilis and 14 B. pumilus, followed by Rhizobium sp. (29 isolates) and Ochrobactrum intermedium (13 isolates). Altogether 93 isolates tolerated the highest concentration (1000 mg kg−1) of at least one of the six tested heavy metals. Five strains were tolerant against all the tested heavy metals, 71 strains tolerated 1,000 mg kg−1 cadmium whereas only one strain tolerated 1,000 mg kg−1 cobalt. Altogether 67% of the bacteria produced indoleacetic acid (IAA), a plant growth-promoting phytohormone. The concentration of IAA produced by 53 isolates was higher than 20 µg ml−1. In total 21% of the bacteria produced siderophore (5.50–167.67 µg ml−1) with two Bacillus sp. producing more than 100 µg ml−1. Eighteen isolates produced both IAA and siderophore. The results suggested that the indigenous bacteria in the soil have beneficial characteristics for remediating the contaminated mine tailing soil. PMID:25188470

  8. Difference in the Minimum Horizontal Stress Magnitudes Between Direct Measurements and Poroelastic Equation-Based Calculation

    Science.gov (United States)

    Vo, U. D.; Chang, C.

    2016-12-01

    Horizontal stress profile with depth is needed for hydraulic fracture design, wellbore stability analysis, and sanding potential assessment. While vertical stress (Sv) can be calculated from overburden, horizontal stresses normally have to be measured. A conventional alternative is to use a linear poroelasticity equation derived based on the assumption of uniaxially strained basins, which gives minimum horizontal stress magnitude (Shmin) as a function of Sv, pore pressure and Poisson's ratio (ν). In order to check the reliability of the equation, we compare the calculated Shmin with measured values through e.g., leak-off tests (LOT). We compile Shmin and pore pressure data from 6 major petroleum fields worldwide (Cuu Long basin, offshore Vietnam; Champion field, offshore Brunei; Visund field, North Sea; Gippsland basin, offshore SE Australia; St. Lawrence Lowlands basin, East Canada; Popeye basin, Gulf of Mexico) for this comparison. For calculation of Shmin via the equation, we assume ν of 0.25 and Biot's constant of unity. The comparison shows that the calculated Shmin values generally underestimate the measured values by a range between 4% and as much as 29% depending on the regions. We attempt to explain qualitatively the gaps between the measured and the calculated Shmin (ΔShmin) in terms of tectonic stress. In Cuu Long, although tectonically active, ΔShmin is quite low (4%) throughout the 4.3 km depth investigated. In contrast, Visund and St. Lawrence Lowlands, although tectonically stable, show appreciable ΔShmin (average 9% and 22% respectively). These results imply that ΔShmin may not depend solely on tectonic stress. In Popeye where tectonics is active, ΔShmin is as high as 24%. Popeye is the only one among the fields investigated that exhibits high ΔShmin likely attributed to tectonic stress. The measured Shmin values in Champion and Gippsland are so scattered that any prediction on magnitudes might not be feasible. The wide variation of

  9. What can granular media teach us about deformation in geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Stephen L. Karner

    2004-06-01

    Experiments on granular media have significantly improved our understanding of deformation processes in porous rocks. Laboratory results have lead to fundamental theoretical developments (such as poroelasticity, or rate and state-variable friction) that have found widespread application. This paper presents results from laboratory experiments that help constrain these theories. Data from triaxial deformation experiments on quartz sand aggregates are used to illustrate stress-dependent behavior of poroelastic parameters (e.g. the Biot-Willis and Skempton coefficients). Calculations for these coefficients show systematic variations as effective stress increases, in a manner consistent with measured compressibilities of the aggregate. Data from shear experiments show that frictional strength varies systematically with time and temperature. At temperatures below 450 oC, shear zones exhibit greater cohesive strengths as the time of stationary contact increases (hence, positive healing rates). For conditions exceeding 450 oC, shear zone strength is seen to decrease with contact time (negative healing rates). The results from both volumetric compaction and frictional shear experiments are well described by poroelasticity as well as rate and state-variable friction. The combination of these constitutive relations may provide a powerful tool that can be used in numerical models that couple thermal, mechanical, hydraulic, and temporal processes – as occur in geothermal systems.

  10. Angle gathers in wave-equation imaging for transversely isotropic media

    KAUST Repository

    Alkhalifah, Tariq Ali

    2010-11-12

    In recent years, wave-equation imaged data are often presented in common-image angle-domain gathers as a decomposition in the scattering angle at the reflector, which provide a natural access to analysing migration velocities and amplitudes. In the case of anisotropic media, the importance of angle gathers is enhanced by the need to properly estimate multiple anisotropic parameters for a proper representation of the medium. We extract angle gathers for each downward-continuation step from converting offset-frequency planes into angle-frequency planes simultaneously with applying the imaging condition in a transversely isotropic with a vertical symmetry axis (VTI) medium. The analytic equations, though cumbersome, are exact within the framework of the acoustic approximation. They are also easily programmable and show that angle gather mapping in the case of anisotropic media differs from its isotropic counterpart, with the difference depending mainly on the strength of anisotropy. Synthetic examples demonstrate the importance of including anisotropy in the angle gather generation as mapping of the energy is negatively altered otherwise. In the case of a titled axis of symmetry (TTI), the same VTI formulation is applicable but requires a rotation of the wavenumbers. © 2010 European Association of Geoscientists & Engineers.

  11. Permeability of the Lucky Strike deep-sea hydrothermal system: Constraints from the poroelastic response to ocean tidal loading

    Science.gov (United States)

    Barreyre, Thibaut; Escartin, Javier; Sohn, Robert; Cannat, Mathilde

    2014-12-01

    We use the time delay between tidal loading and the induced subsurface flow response to constrain the poroelastic behavior and permeability of the Lucky Strike hydrothermal field on the Mid-Atlantic Ridge. We demonstrate that high-temperature (T > 200 °C) exit-fluid discharge records from four hydrothermal sites across the field are highly coherent with contemporaneously acquired bottom pressure records at tidal periods, with the thermal response lagging pressure by ∼155° (5.3 h) on average across all sites for the semi-diurnal (M2) frequency over a three-year observation period. In a one-dimensional poroelastic model of ocean tidal loading this phase lag corresponds to a high-permeability system where pore pressure perturbations at the seafloor rapidly propagate downward from the seafloor interface until they encounter a permeability boundary. Our results suggest that at the Lucky Strike field this tidal pumping is largely restricted to the ∼600 m thick extrusive layer (i.e., seismic layer 2A). Under a plausible set of matrix elastic parameters, the ∼5.3 h lag between pressure and exit-fluid temperature is consistent with an effective matrix permeability of ∼10-10 m2 and an average vertical flow velocity of ∼0.02 m/s within the extrusive layer. Our results argue against tidal pumping of the entire crustal section between the seafloor and the axial magma chamber (at ∼3.4 kmbsf) because this scenario requires unrealistically high effective permeabilities (∼10-9 m2) and average vertical flow velocities (∼0.15 m/s) over this depth range. Our effective permeability estimate for the extrusive layer is broadly consistent with previous results, and indicates that flow must be channeled in discrete permeable pathways (e.g., faults, fissures) that cut through the extrusive volcanic layer.

  12. Reliability of poroelastic equation in determination of minimum horizontal stress in sedimentary basins: implication of tectonic strain

    Science.gov (United States)

    Vo, Uy; Chang, Chandong

    2017-04-01

    Minimum horizontal stress (Shmin) magnitude, normally one of the three principal stresses, provides vital information in various stages of petroleum development such as hydraulic fracture design, wellbore stability analysis, and sand production prediction. Mini-frac or leak-off tests (LOT) are considered to be the technique used to measure Shmin magnitudes directly in the formation. Still, other than being time-consuming and costly, LOT does not give a continuous Shminprofile. A conventional alternative is to use a linear poroelasticity equation derived based on the assumption of uniaxially strained basins, which provides minimum horizontal stress magnitude (Shmin) as a function of vertical stress, pore pressure and Poisson's ratio (ν). In this study, we inspect the reliability of poroelastic equation-based calculation by comparing measured data of Shmin, pore pressure with log-based minimum horizontal stress magnitude in 6 major sedimentary basins worldwide. For calculation of Shmin via the equation, we assume ν of 0.25 and Biot's constant of unity. The comparison shows that the predicted Shmin values generally underestimate the measured values by a range between 4% and as high as 29% depending on the regions. The wide variation of horizontal stress may imply unpredictable complications in the stress states in the sedimentary basins. Besides, we also collect the data of maximum horizontal stress magnitudes and Young's modulus to estimate local tectonic strains, which are responsible for additional stresses over the induced horizontal stresses. The result reveals that the tectonic strain magnitudes are not consistent with the difference between measured and calculated values in minimum horizontal stress. Our results suggest that rock mechanical property such as Young's modulus is a more dominant factor that controls tectonic stress.

  13. Poromechanics of microporous media

    Science.gov (United States)

    Brochard, L.; Vandamme, M.; Pellenq, R. J.-M.

    2012-04-01

    Microporous media, i.e., porous media made of pores with a nanometer size, are important for a variety of applications, for instance for sequestration of carbon dioxide in coal, or for storage of hydrogen in metal-organic frameworks. In a pore of nanometer size, fluid molecules are not in their bulk state anymore since they interact with the atoms of the solid: they are said to be in an adsorbed state. For such microporous media, conventional poromechanics breaks down. In this work we derive poroelastic constitutive equations which are valid for a generic porous medium, i.e., even for a porous medium with pores of nanometer size. The complete determination of the poromechanical behavior of a microporous medium requires knowing how the amount of fluid adsorbed depends on both the fluid bulk pressure and the strain of the medium. The derived constitutive equations are validated with the help of molecular simulations on one-dimensional microporous media. Even when a microporous medium behaves linearly in the absence of any fluid (i.e., its bulk modulus does not depend on strain), we show that fluid adsorption can induce non-linear behavior (i.e., its drained bulk modulus can then depend significantly on strain). We also show that adsorption can lead to an apparent Biot coefficient of the microporous medium greater than unity or smaller than zero. The poromechanical response of a microporous medium to adsorption significantly depends on the pore size distribution. Indeed, the commensurability (i.e., the ratio of the size of the pores to that of the fluid molecules) proves to play a major role. For a one-dimensional model of micropores with a variety of pore sizes, molecular simulations show that the amount of adsorbed fluid depends linearly on the strain of the medium. We derive linearized constitutive equations which are valid when such a linear dependence of the adsorbed amount of fluid on the strain is observed. As an application, the case of methane and coal is

  14. Moveout-based geometrical-spreading correction for PS-waves in layered anisotropic media

    Science.gov (United States)

    Xu, Xiaoxia; Tsvankin, Ilya

    2008-06-01

    This paper is devoted to pre-stack amplitude analysis of reflection seismic data from anisotropic (e.g., fractured) media. Geometrical-spreading correction is an important component of amplitude-variation-with-offset (AVO) analysis, which provides high-resolution information for anisotropic parameter estimation and fracture characterization. Here, we extend the algorithm of moveout-based anisotropic spreading correction (MASC) to mode-converted PSV-waves in VTI (transversely isotropic with a vertical symmetry axis) media and symmetry planes of orthorhombic media. While the geometrical-spreading equation in terms of reflection traveltime has the same form for all wave modes in laterally homogeneous media, reflection moveout of PS-waves is more complicated than that of P-waves (e.g., it can become asymmetric in common-midpoint geometry). Still, for models with a horizontal symmetry plane, long-spread reflection traveltimes of PS waves can be well approximated by the Tsvankin-Thomsen and Alkhalifah-Tsvankin moveout equations, which are widely used for P-waves. Although the accuracy of the Alkhalifah-Tsvankin equation is somewhat lower, it includes fewer moveout parameters and helps to maintain the uniformity of the MASC algorithm for P- and PS-waves. The parameters of both moveout equations are obtained by least-squares traveltime fitting or semblance analysis and are different from those for P-waves. Testing on full-waveform synthetic data generated by the reflectivity method for layered VTI media confirms that MASC accurately reconstructs the plane-wave conversion coefficient from conventional-spread PS data. Errors in the estimated conversion coefficient, which become noticeable at moderate and large offsets, are mostly caused by the offset-dependent transmission loss of PS-waves.

  15. Poro-mechanics: from linear to nonlinear poro-elasticity and poro-visco-elasticity; Poromecanique: de la poroelasticite lineaire a la poroelasticite non lineaire et la poroviscoelasticite

    Energy Technology Data Exchange (ETDEWEB)

    Bemer, E.; Bouteca, M.; Vincke, O. [Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France); Hoteit, N.; Ozanam, O. [Agence Nationale pour la Gestion des Dechets Radioactifs ANDRA, 92 - Chatenay Malabry (France)

    2001-07-01

    Due to the impact on productivity and oil an place estimates, reliable modeling of rock behavior is essential in reservoir engineering. This paper examines several aspects of rock poro-elastic behavior within the framework of Biot's mechanics of fluid saturated porous solids. Constitutive laws of linear and nonlinear poro-elasticity are first determined from a fundamental stress decomposition, which allows to clearly connect linear and nonlinear models. Concept of effective stress and rock compressibility are considered. Linear incremental stress-strain relations are derived from the proposed nonlinear constitutive law by defining tangent elastic properties. These characteristics are naturally functions of strains and pore pressure, but explicit expressions as functions of stresses and pore pressure are established herein. Experiments performed on a reservoir sandstone illustrate these points. A constitutive law of poro-visco-elasticity is finally presented and applied to experimental data obtained on clay. (authors)

  16. The diffraction of Rayleigh waves by a fluid-saturated alluvial valley in a poroelastic half-space modeled by MFS

    Science.gov (United States)

    Liu, Zhongxian; Liang, Jianwen; Wu, Chengqing

    2016-06-01

    Two dimensional diffraction of Rayleigh waves by a fluid-saturated poroelastic alluvial valley of arbitrary shape in a poroelastic half-space is investigated using the method of fundamental solutions (MFS). To satisfy the free surface boundary conditions exactly, Green's functions of compressional (PI and PII) and shear (SV) wave sources buried in a fluid-saturated poroelastic half-space are adopted. Next, the procedure for solving the scattering wave field is presented. It is verified that the MFS is of excellent accuracy and numerical stability. Numerical results illustrate that the dynamic response strongly depends on such factors as the incident frequency, the porosity of alluvium, the boundary drainage condition, and the valley shape. There is a significant difference between the diffraction of Rayleigh waves for the saturated soil case and for the corresponding dry soil case. The wave focusing effect both on the displacement and pore pressure can be observed inside the alluvial valley and the amplification effect seems most obvious in the case of higher porosity and lower frequency. Additionally, special attention should also be paid to the concentration of pore pressure, which is closely related to the site liquefaction in earthquakes.

  17. First-arrival traveltime tomography for anisotropic media using the adjoint-state method

    KAUST Repository

    Waheed, Umair bin

    2016-05-27

    Traveltime tomography using transmission data has been widely used for static corrections and for obtaining near-surface models for seismic depth imaging. More recently, it is also being used to build initial models for full-waveform inversion. The classic traveltime tomography approach based on ray tracing has difficulties in handling large data sets arising from current seismic acquisition surveys. Some of these difficulties can be addressed using the adjoint-state method, due to its low memory requirement and numerical efficiency. By coupling the gradient computation to nonlinear optimization, it avoids the need for explicit computation of the Fréchet derivative matrix. Furthermore, its cost is equivalent to twice the solution of the forward-modeling problem, irrespective of the size of the input data. The presence of anisotropy in the subsurface has been well established during the past few decades. The improved seismic images obtained by incorporating anisotropy into the seismic processing workflow justify the effort. However, previous literature on the adjoint-state method has only addressed the isotropic approximation of the subsurface. We have extended the adjoint-state technique for first-arrival traveltime tomography to vertical transversely isotropic (VTI) media. Because δ is weakly resolvable from surface seismic alone, we have developed the mathematical framework and procedure to invert for vNMO and η. Our numerical tests on the VTI SEAM model demonstrate the ability of the algorithm to invert for near-surface model parameters and reveal the accuracy achievable by the algorithm.

  18. Poroelastic stress-triggering of the 2005 M8.7 Nias earthquake by the 2004 M9.2 Sumatra-Andaman earthquake

    Science.gov (United States)

    Hughes, K.L.H.; Masterlark, Timothy; Mooney, W.D.

    2010-01-01

    The M9.2 Sumatra-Andaman earthquake (SAE) occurred three months prior to the M8.7 Nias earthquake (NE). We propose that the NE was mechanically triggered by the SAE, and that poroelastic effects were a major component of this triggering. This study uses 3D finite element models (FEMs) of the Sumatra-Andaman subduction zone (SASZ) to predict the deformation, stress, and pore pressure fields of the SAE. The coseismic slip distribution for the SAE is calibrated to near-field GPS data using FEM-generated Green's Functions and linear inverse methods. The calibrated FEM is then used to predict the postseismic poroelastic contribution to stress-triggering along the rupture surface of the NE, which is adjacent to the southern margin of the SAE. The coseismic deformation of the SAE, combined with the rheologic configuration of the SASZ produces two transient fluid flow regimes having separate time constants. SAE coseismic pore pressures in the relatively shallow forearc and volcanic arc regions (within a few km depth) dissipate within one month after the SAE. However, pore pressures in the oceanic crust of the down-going slab persist several months after the SAE. Predictions suggest that the SAE initially induced MPa-scale negative pore pressure near the hypocenter of the NE. This pore pressure slowly recovered (increased) during the three-month interval separating the SAE and NE due to lateral migration of pore fluids, driven by coseismic pressure gradients, within the subducting oceanic crust. Because pore pressure is a fundamental component of Coulomb stress, the MPa-scale increase in pore pressure significantly decreased stability of the NE fault during the three-month interval after the SAE and prior to rupture of the NE. A complete analysis of stress-triggering due to the SAE must include a poroelastic component. Failure to include poroelastic mechanics will lead to an incomplete model that cannot account for the time interval between the SAE and NE. Our transient

  19. The effect of degenerative morphological changes of the intervertebral disc on the lumbar spine biomechanics: a poroelastic finite element investigation.

    Science.gov (United States)

    Galbusera, Fabio; Schmidt, Hendrik; Neidlinger-Wilke, Cornelia; Wilke, Hans-Joachim

    2011-08-01

    Intervertebral disc degeneration involves changes in the spinal anatomical structures. The mechanical relevance of the following changes was investigated: disc height, endplate sclerosis, disc water content, permeability and depressurisation. A poroelastic nonlinear finite element model of the L4-L5 human spine segments was employed. Loads represented a daily cycle (500 N compression combined with flexion-extension motion for 16 h followed by 200 N compression for 8 h). In non-degenerative conditions, the model predicted a diurnal axial displacement of 1.32 mm and a peak intradiscal pressure of 0.47 MPa. Axial displacement, facet force and range of motion in flexion-extension are decreased by decreasing disc height. By decreasing the initial water content, axial displacement, facet force and fluid loss were all reduced. Endplate sclerosis did not have a significant influence on the calculated results. Depressurisation determined an increase of the disc effective stress, possibly inducing failure. Degenerative instability was not calculated in any simulations.

  20. Seismoelectric couplings in a poroelastic material containing two immiscible fluid phases

    Science.gov (United States)

    Jardani, A.; Revil, A.

    2015-08-01

    A new approach of seismoelectric imaging has been recently proposed to detect saturation fronts in which seismic waves are focused in the subsurface to scan its heterogeneous nature and determine saturation fronts. Such type of imaging requires however a complete modelling of the seismoelectric properties of porous media saturated by two immiscible fluid phases, one being usually electrically insulating (for instance water and oil). We combine an extension of Biot dynamic theory, valid for porous media containing two immiscible Newtonian fluids, with an extension of the electrokinetic theory based on the notion of effective volumetric charge densities dragged by the flow of each fluid phase. These effective charge densities can be related directly to the permeability and saturation of each fluid phase. The coupled partial differential equations are solved with the finite element method. We also derive analytically the transfer function connecting the macroscopic electrical field to the acceleration of the fast P wave (coseismic electrical field) and we study the influence of the water content on this coupling. We observe that the amplitude of the co-seismic electrical disturbance is very sensitive to the water content with an increase in amplitude with water saturation. We also investigate the seismoelectric conversions (interface effect) occurring at the water table. We show that the conversion response at the water table can be identifiable only when the saturation contrasts between the vadose and saturated zones are sharp enough. A relatively dry vadose zone represents the best condition to identify the water table through seismoelectric measurements. Indeed, in this case, the coseismic electrical disturbances are vanishingly small compared to the seismoelectric interface response.

  1. Pore-fluid effects on seismic waves in vertically fractured earth with orthotropic symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Berryman, J.G.

    2010-05-15

    For elastically noninteracting vertical-fracture sets at arbitrary orientation angles to each other, a detailed model is presented in which the resulting anisotropic fractured medium generally has orthorhombic symmetry overall. Some of the analysis methods and ideas of Schoenberg are emphasized, together with their connections to other similarly motivated and conceptually related methods by Sayers and Kachanov, among others. Examples show how parallel vertical-fracture sets having HTI (horizontal transversely isotropic) symmetry transform into orthotropic fractured media if some subsets of the vertical fractures are misaligned with the others, and then the fractured system can have VTI (vertical transversely isotropic) symmetry if all of the fractures are aligned randomly or half parallel and half perpendicular to a given vertical plane. An orthotropic example having vertical fractures in an otherwise VTI earth system (studied previously by Schoenberg and Helbig) is compared with the other examples treated and it is finally shown how fluids in the fractures affect the orthotropic poroelastic system response to seismic waves. The key result is that fracture-influence parameters are multiplied by a factor of (1-B), where 0 {le} B < 1 is Skempton's second coefficient for poroelastic media. Skempton's B coefficient is itself a measurable characteristic of fluid-saturated porous rocks, depending on porosity, solid moduli, and the pore-fluid bulk modulus. For heterogeneous porous media, connections between the present work and earlier related results of Brown and Korringa are also established.

  2. Exploring the efficacy of endoscopic ventriculostomy for hydrocephalus treatment via a multicompartmental poroelastic model of CSF transport: a computational perspective.

    Science.gov (United States)

    Vardakis, John C; Tully, Brett J; Ventikos, Yiannis

    2013-01-01

    This study proposes the implementation of a Multiple-Network Poroelastic Theory (MPET) model coupled with finite-volume computational fluid dynamics for the purpose of studying, in detail, the effects of obstructing CSF transport within an anatomically accurate cerebral environment. The MPET representation allows the investigation of fluid transport between CSF, brain parenchyma and cerebral blood, in an integral and comprehensive manner. A key novelty in the model is the amalgamation of anatomically accurate choroid plexuses with their feeding arteries and a simple relationship relaxing the constraint of a unique permeability for the CSF compartment. This was done in order to account for the Aquaporin-4-mediated swelling characteristics. The aim of this varying permeability compartment was to bring to light a feedback mechanism that could counteract the effects of ventricular dilation and subsequent elevations of CSF pressure through the efflux of excess CSF into the blood system. This model is used to demonstrate the impact of aqueductal stenosis and fourth ventricle outlet obstruction (FVOO). The implications of treating such a clinical condition with the aid of endoscopic third (ETV) and endoscopic fourth (EFV) ventriculostomy are considered. We observed peak CSF velocities in the aqueduct of the order of 15.6 cm/s in the healthy case, 45.4 cm/s and 72.8 cm/s for the mild and severe cases respectively. The application of ETV reduced the aqueductal velocity to levels around 16-17 cm/s. Ventricular displacement, CSF pressure, wall shear stress (WSS) and pressure difference between lateral and fourth ventricles (ΔP) increased with applied stenosis, and subsequently dropped to nominal levels with the application of ETV. The greatest reversal of the effects of atresia come by opting for ETV rather than the more complicated procedure of EFV.

  3. Exploring the efficacy of endoscopic ventriculostomy for hydrocephalus treatment via a multicompartmental poroelastic model of CSF transport: a computational perspective.

    Directory of Open Access Journals (Sweden)

    John C Vardakis

    Full Text Available This study proposes the implementation of a Multiple-Network Poroelastic Theory (MPET model coupled with finite-volume computational fluid dynamics for the purpose of studying, in detail, the effects of obstructing CSF transport within an anatomically accurate cerebral environment. The MPET representation allows the investigation of fluid transport between CSF, brain parenchyma and cerebral blood, in an integral and comprehensive manner. A key novelty in the model is the amalgamation of anatomically accurate choroid plexuses with their feeding arteries and a simple relationship relaxing the constraint of a unique permeability for the CSF compartment. This was done in order to account for the Aquaporin-4-mediated swelling characteristics. The aim of this varying permeability compartment was to bring to light a feedback mechanism that could counteract the effects of ventricular dilation and subsequent elevations of CSF pressure through the efflux of excess CSF into the blood system. This model is used to demonstrate the impact of aqueductal stenosis and fourth ventricle outlet obstruction (FVOO. The implications of treating such a clinical condition with the aid of endoscopic third (ETV and endoscopic fourth (EFV ventriculostomy are considered. We observed peak CSF velocities in the aqueduct of the order of 15.6 cm/s in the healthy case, 45.4 cm/s and 72.8 cm/s for the mild and severe cases respectively. The application of ETV reduced the aqueductal velocity to levels around 16-17 cm/s. Ventricular displacement, CSF pressure, wall shear stress (WSS and pressure difference between lateral and fourth ventricles (ΔP increased with applied stenosis, and subsequently dropped to nominal levels with the application of ETV. The greatest reversal of the effects of atresia come by opting for ETV rather than the more complicated procedure of EFV.

  4. A poroelastic finite element model of the bone-cartilage unit to determine the effects of changes in permeability with osteoarthritis.

    Science.gov (United States)

    Stender, Michael E; Regueiro, Richard A; Ferguson, Virginia L

    2017-02-01

    The changes experienced in synovial joints with osteoarthritis involve coupled chemical, biological, and mechanical processes. The aim of this study was to investigate the consequences of increasing permeability in articular cartilage (AC), calcified cartilage (CC), subchondral cortical bone (SCB), and subchondral trabecular bone (STB) as observed with osteoarthritis. Two poroelastic finite element models were developed using a depth-dependent anisotropic model of AC with strain-dependent permeability and poroelastic models of calcified tissues (CC, SCB, and STB). The first model simulated a bone-cartilage unit (BCU) in uniaxial unconfined compression, while the second model simulated spherical indentation of the AC surface. Results indicate that the permeability of AC is the primary determinant of the BCU's poromechanical response while the permeability of calcified tissues exerts no appreciable effect on the force-indentation response of the BCU. In spherical indentation simulations with osteoarthritic permeability properties, fluid velocities were larger in magnitude and distributed over a smaller area compared to normal tissues. In vivo, this phenomenon would likely lead to chondrocyte death, tissue remodeling, alterations in joint lubrication, and the progression of osteoarthritis. For osteoarthritic and normal tissue permeability values, fluid flow was predicted to occur across the osteochondral interface. These results help elucidate the consequences of increases in the permeability of the BCU that occur with osteoarthritis. Furthermore, this study may guide future treatments to counteract osteoarthritis.

  5. Poroelastic properties of the Arbuckle Group in Oklahoma derived from well fluid level response to the 3 September 2016 Mw 5.8 Pawnee and 7 November 2016 Mw 5.0 Cushing earthquakes

    Science.gov (United States)

    Kroll, Kayla A.; Cochran, Elizabeth S.; Murray, Kyle E.

    2017-01-01

    The Arbuckle Group (Arbuckle) is a basal sedimentary unit that is the primary target for saltwater disposal in Oklahoma. Thus, the reservoir characteristics of the Arbuckle, including how the poroelastic properties change laterally and over time are of significant interest. We report observations of fluid level changes in two monitoring wells in response to the 3 September 2016 Mw 5.8 Pawnee and the 7 November 2016 Mw 5.0 Cushing earthquakes. We investigate the relationship between static strain resulting from these events and the fluid level changes observed in the wells. We model the fluid level response by estimating static strains from a set of earthquake source parameters and spatiotemporal poroelastic properties of the Arbuckle in the neighborhood of the monitoring wells. Results suggest that both the direction of the observed fluid level step and the amplitude can be predicted from the computed volumetric strain change and a reasonable set of poroelastic parameters. Modeling results indicate that poroelastic parameters differ at the time of the Pawnee and Cushing earthquakes, with a moderately higher Skempton’s coefficient required to fit the response to the Cushing earthquake. This may indicate that dynamic shaking resulted in physical alteration of the Arbuckle at distances up to ∼50  km from the Pawnee earthquake.

  6. Media education.

    Science.gov (United States)

    Strasburger, Victor C

    2010-11-01

    The American Academy of Pediatrics recognizes that exposure to mass media (eg, television, movies, video and computer games, the Internet, music lyrics and videos, newspapers, magazines, books, advertising) presents health risks for children and adolescents but can provide benefits as well. Media education has the potential to reduce the harmful effects of media and accentuate the positive effects. By understanding and supporting media education, pediatricians can play an important role in reducing harmful effects of media on children and adolescents.

  7. Fundamentals of multiphase, gas-solid and gas-liquid flows in porous media

    Science.gov (United States)

    Mazaheri, Ali Reza

    This thesis is concerned with fundamentals and applications of multiphase and particulate flows. The study contains three parts covering gas-liquid flows through porous media, gas-solid flows and Chemical-Mechanical Polishing (CMP). A continuum model for multiphase fluid flows through poro-elastic media is developed. It is shown that the present theory leads to the extended Darcy's law and contains, as its special case, Biot's theory of saturated poro-elastic media. The capillary pressure formulation derived from the new model is used and the equation governing the evolution of the saturation and its temporal variation in porous media is derived. The resulting nonlinear diffusion equation is then solved numerically. The results show that the capillary hysteresis occurs when the temporal variation of saturation is included. Application of the developed model to CO2 sequestration is discussed. Computer simulations of dilute Gas-Solid flows in complex geometry regions are studied. A procedure for handling particle trajectory analysis in unstructured grid is developed. Examples of particle transport and removal in human lung and hot-gas cleaning systems are presented. The simulation results for the human lung show that the capture efficiency is affected by the turbulence in the upper three bifurcation airways. Computer simulations of gas-solid flows in hot-gas cleaning for a demonstration scale filtration system is studied in details. Alternative designs of the filter vessel are proposed. The corresponding vessel performance are numerically simulated. Chemical mechanical polishing (CMP) has become critical to the fabrication of advanced multilevel integrated circuit in microelectronic industry. The effect of course surface roughness of abrasive particles on the polishing rate in CMP is studied. The effects of slurry pH and double layer attraction and repulsion on chemical-mechanical polishing are also studied. It is shown that the slurry pH and colloidal forces

  8. Media Komunitas dan Media Literacy

    Directory of Open Access Journals (Sweden)

    Pawito .

    2013-12-01

    Full Text Available Abstract:This essay deals with community media in relation to media literacy. After a short discussion on a number of community media characters is made the essay goes further with somewhat detail theoretical presumptions of the roles of media community with respect primarily to the development as Amartya Sen mentioned about. The author suggests that community media may play some significant roles in the development including (a disseminating information (from varieties of perspective, (b facilitating public discussion, (c helping to reach solutions of problems, (d encouraging participations, and (e encouraging the development of media literacy. Regarding the last point the author remarks that media community may have a dual-roles i.e facilitating community’s member in media participation and facilitating community’s member in media education.

  9. Media, Gadgets.

    Science.gov (United States)

    Journal of Chemical Education, 1981

    1981-01-01

    Summarizes papers presented at the Sixth Biennial Conference on Chemical Education describing new media and gadgets, particularly models, computers, and other media. A bibliography of 15 presented papers on these topics is attached. (CS)

  10. Decoupled equations for reverse time migration in tilted transversely isotropic media

    KAUST Repository

    Zhan, Ge

    2012-03-01

    Conventional modeling and migration for tilted transversely isotropic (TTI) media may suffer from numerical instabilities and shear wave artifacts due to the coupling of the P-wave and SV-wave modes in the TTI coupled equations. Starting with the separated P- and SV-phase velocity expressions for vertical transversely isotropic (VTI) media, we extend these decoupled equations for modeling and reverse time migration (RTM) in acoustic TTI media. Compared with the TTI coupled equations published in the geophysical literature, the new TTI decoupled equations provide a more stable solution due to the complete separation of the P-wave and SV-wave modes. The pseudospectral method is the most convenient method to implement these equations due to the form of wavenumber expressions and has the added benefit of being highly accurate and thus avoiding numerical dispersion. The rapid expansion method (REM) in time is employed to produce a broad band numerically stable time evolution of the wavefields. Synthetic results validate the proposed TTI decoupled equations and show that modeling and RTM in TTI media with the decoupled equations remain numerically stable even for models with strong anisotropy and sharp contrasts. © 2012 Society of Exploration Geophysicists.

  11. On sound transmission through double-walled cylindrical shells lined with poroelastic material: Comparison with Zhou's results and further effect of external mean flow

    Science.gov (United States)

    Liu, Yu; He, Chuanbo

    2015-12-01

    In this discussion, the corrections to the errors found in the derivations and the numerical code of a recent analytical study (Zhou et al. Journal of Sound and Vibration 333 (7) (2014) 1972-1990) on sound transmission through double-walled cylindrical shells lined with poroelastic material are presented and discussed, as well as the further effect of the external mean flow on the transmission loss. After applying the corrections, the locations of the characteristic frequencies of thin shells remain unchanged, as well as the TL results above the ring frequency where BU and UU remain the best configurations in sound insulation performance. In the low-frequency region below the ring frequency, however, the corrections attenuate the TL amplitude significantly for BU and UU, and hence the BB configuration exhibits the best performance which is consistent with previous observations for flat sandwich panels.

  12. Determination of the mechanical and physical properties of cartilage by coupling poroelastic-based finite element models of indentation with artificial neural networks.

    Science.gov (United States)

    Arbabi, Vahid; Pouran, Behdad; Campoli, Gianni; Weinans, Harrie; Zadpoor, Amir A

    2016-03-21

    One of the most widely used techniques to determine the mechanical properties of cartilage is based on indentation tests and interpretation of the obtained force-time or displacement-time data. In the current computational approaches, one needs to simulate the indentation test with finite element models and use an optimization algorithm to estimate the mechanical properties of cartilage. The modeling procedure is cumbersome, and the simulations need to be repeated for every new experiment. For the first time, we propose a method for fast and accurate estimation of the mechanical and physical properties of cartilage as a poroelastic material with the aid of artificial neural networks. In our study, we used finite element models to simulate the indentation for poroelastic materials with wide combinations of mechanical and physical properties. The obtained force-time curves are then divided into three parts: the first two parts of the data is used for training and validation of an artificial neural network, while the third part is used for testing the trained network. The trained neural network receives the force-time curves as the input and provides the properties of cartilage as the output. We observed that the trained network could accurately predict the properties of cartilage within the range of properties for which it was trained. The mechanical and physical properties of cartilage could therefore be estimated very fast, since no additional finite element modeling is required once the neural network is trained. The robustness of the trained artificial neural network in determining the properties of cartilage based on noisy force-time data was assessed by introducing noise to the simulated force-time data. We found that the training procedure could be optimized so as to maximize the robustness of the neural network against noisy force-time data. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Media Entrepreneurship

    DEFF Research Database (Denmark)

    Khajeheian, Datis

    2017-01-01

    Media Entrepreneurship has been an ambiguous, unclear and controversial concept and despite of growing academic efforts in the last decade, it is still a poorly defined subject. This paper is an effort to fill this gap by providing a comprehensive definition of media entrepreneurship. Firstly......, a literature review conducted and entrepreneurship, media, opportunity and innovation as building blocks of media entrepreneurship explained. Then by using of a mixed of bibliographic method and a Delphi method with multi-stage analysis process, a consensual definition of media entrepreneurship proposed...... entrepreneurship....

  14. Media Technology

    Directory of Open Access Journals (Sweden)

    Zhou Gang

    2016-01-01

    Full Text Available Modern colleges are faced with the dual pressures of university reform and international competition, how to overcome difficulties, to play the role of modern English teaching in colleges and colleges to enhance the core competitiveness of colleges, colleges and colleges modern English teaching problems to be solved. Based on the current situation of modern colleges in the premise of the Modern media platform fully demonstrated the characteristics and viability of the Modern media English teaching, the necessity of modern English teaching of college Modern media. Discusses the Modern media targeting English teaching and important role is in the English teaching to guide the development of modern colleges modern media.

  15. Media Framing

    DEFF Research Database (Denmark)

    Pedersen, Rasmus T.

    2017-01-01

    The concept of media framing refers to the way in which the news media organize and provide meaning to a news story by emphasizing some parts of reality and disregarding other parts. These patterns of emphasis and exclusion in news coverage create frames that can have considerable effects on news...... consumers’ perceptions and attitudes regarding the given issue or event. This entry briefly elaborates on the concept of media framing, presents key types of media frames, and introduces the research on media framing effects....

  16. An Introduction to Poroelasticity

    DEFF Research Database (Denmark)

    Andersen, Lars

    In the following, the continuum model for a fully saturated porous material is presented. The theory is mainly due to M.A. Biot. We shall only consider a two-phase system consisting of a solid skeleton and a single pore fluid, e.g. water. The theory for three-dimensional consolidation is develope...

  17. Media stylistics

    OpenAIRE

    Lambrou, Marina; Durant, Alan

    2014-01-01

    In this chapter we review the concept of ‘media stylistics’. In particular, we disentangle the polysemy of these two terms which, when combined, describe but can also obscure work in this area; and we discuss key themes and concerns which emerge. Through analysis of two short extracts of media discourse in English, we elaborate a distinction between two alternative emphases: study of media language as concerned with the capabilities associated with changing technologies for conveying linguist...

  18. Media Flow

    DEFF Research Database (Denmark)

    Kabel, Lars

    2016-01-01

    News and other kinds of journalistic stories, 16-17 hours a day, all year round, on all platforms, also the moderated social media. The key research thesis behind this article is that the continuous and speedy stream of news stories and media content now is becoming the centre of the production...... processes and the value creation in converged multimedia newsrooms. The article identify new methods and discuss editorial challenges in handling media flow....

  19. Print media vs internet media

    OpenAIRE

    Koganuramath, M. M.; Angadi, Mallikarjun

    1999-01-01

    The Information Technology has revolutionised the communication media with the emergence of Internet. This paper describes the pace of change in print media to On-line journalism. The process has began with On-line journalism utilising Internet wherein websites are replacing the print media. Most of the On-line newspapers are free, interactive and archival in nature and it provides users to search the information on newspapers through various access points i.e. by contributors, title, and dat...

  20. Media darling

    CERN Multimedia

    Chalmers, Matthew

    2008-01-01

    He is the media-friendly face of particle physics, appearing on countless TV and radio shows in the run-up to the opening of CERN's Large Hadron Collider. Matthew Chalmers discovers how Brian Cox finds the time to be both a physicist and a media personality. (2 pages)

  1. Media violence.

    Science.gov (United States)

    Cantor, J

    2000-08-01

    Research on the effects of media violence is not well understood by the general public. Despite this fact, there is an overwhelming consensus in the scientific literature about the unhealthy effects of media violence. Meta-analyses show that media-violence viewing consistently is associated with higher levels of antisocial behavior, ranging from the trivial (imitative violence directed against toys) to the serious (criminal violence), with many consequential outcomes in between (acceptance of violence as a solution to problems, increased feelings of hostility, and the apparent delivery of painful stimulation to another person). Desensitization is another well-documented effect of viewing violence, which is observable in reduced arousal and emotional disturbance while witnessing violence, the reduced tendency to intervene in a fight, and less sympathy for the victims of violence. Although there is evidence that youth who are already violent are more likely to seek out violent entertainment, there is strong evidence that the relationship between violence viewing and antisocial behavior is bidirectional. There is growing evidence that media violence also engenders intense fear in children which often lasts days, months, and even years. The media's potential role in solutions to these problems is only beginning to be explored, in investigations examining the uses and effects of movie ratings, television ratings, and the V-chip, and the effects of media literacy programs and public education efforts. Future research should explore important individual differences in responses to media violence and effective ways to intervene in the negative effects.

  2. SOCIAL MEDIA

    National Research Council Canada - National Science Library

    Christine Weiser

    2013-01-01

      For the leaders assembled in the SchoolCIO working group, it seems the most successful implementations of social media use are found in those schools that recognize the importance of guiding students in their journey...

  3. From Augmentation Media to Meme Media.

    Science.gov (United States)

    Tanaka, Yuzuru

    Computers as meta media are now evolving from augmentation media vehicles to meme media vehicles. While an augmentation media system provides a seamlessly integrated environment of various tools and documents, meme media system provides further functions to edit and distribute tools and documents. Documents and tools on meme media can easily…

  4. Community Media: Muting the Democratic Media Discourse?

    NARCIS (Netherlands)

    Carpentier, N.; Lie, R.; Servaes, J.

    2003-01-01

    Focuses on the concept of community media. Components that construct the identity of community media; Multi-theoretical approaches for analysis of community media; Definition of community media based on the concept of alternative media; Link between community media and civil society; Problems faced

  5. Media Bias

    OpenAIRE

    Sendhil Mullainathan; Andrei Shleifer

    2002-01-01

    There are two different types of media bias. One bias, which we refer to as ideology, reflects a news outlet's desire to affect reader opinions in a particular direction. The second bias, which we refer to as spin, reflects the outlet's attempt to simply create a memorable story. We examine competition among media outlets in the presence of these biases. Whereas competition can eliminate the effect of ideological bias, it actually exaggerates the incentive to spin stories.

  6. A Poroelastic Fluid/Structure-Interaction Model of Cerebrospinal Fluid Dynamics in the Cord With Syringomyelia and Adjacent Subarachnoid-Space Stenosis.

    Science.gov (United States)

    Bertram, C D; Heil, M

    2017-01-01

    An existing axisymmetric fluid/structure-interaction (FSI) model of the spinal cord, pia mater, subarachnoid space, and dura mater in the presence of syringomyelia and subarachnoid-space stenosis was modified to include porous solids. This allowed investigation of a hypothesis for syrinx fluid ingress from cerebrospinal fluid (CSF). Gross model deformation was unchanged by the addition of porosity, but pressure oscillated more in the syrinx and the subarachnoid space below the stenosis. The poroelastic model still exhibited elevated mean pressure in the subarachnoid space below the stenosis and in the syrinx. With realistic cord permeability, there was slight oscillatory shunt flow bypassing the stenosis via the porous tissue over the syrinx. Weak steady streaming flow occurred in a circuit involving craniocaudal flow through the stenosis and back via the syrinx. Mean syrinx volume was scarcely altered when the adjacent stenosis bisected the syrinx, but increased slightly when the syrinx was predominantly located caudal to the stenosis. The fluid content of the tissues over the syrinx oscillated, absorbing most of the radial flow seeping from the subarachnoid space so that it did not reach the syrinx. To a lesser extent, this cyclic swelling in a boundary layer of cord tissue just below the pia occurred all along the cord, representing a mechanism for exchange of interstitial fluid (ISF) and cerebrospinal fluid which could explain recent tracer findings without invoking perivascular conduits. The model demonstrates that syrinx volume increase is possible when there is subarachnoid-space stenosis and the cord and pia are permeable.

  7. Oscillations and uniaxial mechanochemical waves in a model of an active poroelastic medium: Application to deformation patterns in protoplasmic droplets of Physarum polycephalum

    Science.gov (United States)

    Alonso, Sergio; Strachauer, Ulrike; Radszuweit, Markus; Bär, Markus; Hauser, Marcus J. B.

    2016-04-01

    Self-organization in cells often manifests itself in oscillations and waves. Here, we address deformation waves in protoplasmic droplets of the plasmodial slime mould Physarum polycephalum by modelling and experiments. In particular, we extend a one-dimensional model that considered the cell as a poroelastic medium, where active tension caused mechanochemical waves that were regulated by an inhibitor (Radszuweit et al., 2013). Our extension consists of a simple, qualitative chemical reaction-diffusion model (Brusselator) that describes the regulation of the inhibitor by another biochemical species. The biochemical reaction enhances the formation of mechanochemical waves if the reaction rates and input concentrations are near or inside an oscillatory regime. The period of the waves is found to be controlled by the characteristic oscillation period, whereas their wavelength is set by mechanical parameters. The model also allows for a systematic study of the chemical activity at the onset of mechanochemical waves. We also present examples for pattern formation in protoplasmic droplets of Physarum polycephalum including global oscillations where the central region of the droplets is in antiphase to the boundary zone, as well as travelling and standing wave-like uniaxial patterns. Finally, we apply our model to reproduce these experimental results by identifying the active tension inhibitor with the intracellular calcium concentration in the Physarum droplets and by using parameter values from mechanical experiments, respectively knowledge about the properties of calcium oscillations in Physarum. The simulation results are then found to be in good agreement with the experimental observations.

  8. A pseudo-spectral method for the simulation of poro-elastic seismic wave propagation in 2D polar coordinates using domain decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Sidler, Rolf, E-mail: rsidler@gmail.com [Center for Research of the Terrestrial Environment, University of Lausanne, CH-1015 Lausanne (Switzerland); Carcione, José M. [Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Borgo Grotta Gigante 42c, 34010 Sgonico, Trieste (Italy); Holliger, Klaus [Center for Research of the Terrestrial Environment, University of Lausanne, CH-1015 Lausanne (Switzerland)

    2013-02-15

    We present a novel numerical approach for the comprehensive, flexible, and accurate simulation of poro-elastic wave propagation in 2D polar coordinates. An important application of this method and its extensions will be the modeling of complex seismic wave phenomena in fluid-filled boreholes, which represents a major, and as of yet largely unresolved, computational problem in exploration geophysics. In view of this, we consider a numerical mesh, which can be arbitrarily heterogeneous, consisting of two or more concentric rings representing the fluid in the center and the surrounding porous medium. The spatial discretization is based on a Chebyshev expansion in the radial direction and a Fourier expansion in the azimuthal direction and a Runge–Kutta integration scheme for the time evolution. A domain decomposition method is used to match the fluid–solid boundary conditions based on the method of characteristics. This multi-domain approach allows for significant reductions of the number of grid points in the azimuthal direction for the inner grid domain and thus for corresponding increases of the time step and enhancements of computational efficiency. The viability and accuracy of the proposed method has been rigorously tested and verified through comparisons with analytical solutions as well as with the results obtained with a corresponding, previously published, and independently benchmarked solution for 2D Cartesian coordinates. Finally, the proposed numerical solution also satisfies the reciprocity theorem, which indicates that the inherent singularity associated with the origin of the polar coordinate system is adequately handled.

  9. The impact of ventilation tubes in otitis media on the risk of cholesteatoma on a national level

    DEFF Research Database (Denmark)

    Djurhuus, Bjarki Ditlev; Christensen, Kaare; Skytthe, Axel

    We found that prolonged OM requiring multiple VTIs was associated with an increased risk of STMEC1. Early age at first VTI and short time between two VTIs was associated with a lower risk of STMEC1. This may be the result of reduced time with negative middle ear pressure and OM. However......, these findings may be susceptible to selection bias, as age at first VTI and time between VTIs, as well as the outcome variable, STMEC1, may all depend on the underlying indication for VTI. In short the present study suggests that treatment with VTI in children with OM reduces the risk of STMEC1 on a population...... level. However, for the individual child the absolute risk reduction is very small, and the decision of treatment with VTI must always rely on the symptoms and clinical findings in the individual child....

  10. Social media management and media environment

    OpenAIRE

    Šiđanin Iva

    2012-01-01

    The paper deals with the system of services that social media management can offer to a variety of users. As social media systems are emerging, social media management can strengthen teams in social media and help to manage numerous social channels and distribution of social information from one place. Social media management is a system of procedures that are used to manage the flow of information in the environment of social media. This involves connecting with social media like Facebook, T...

  11. Media Training

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    With the LHC starting up soon, the world's media are again turning their attention to CERN. We're all likely to be called upon to explain what is happening at CERN to media, friends and neighbours. The seminar will be given by BBC television news journalists Liz Pike and Nadia Marchant, and will deal with the kind of questions we're likely to be confronted with through the restart period. The training is open for everybody. Make sure you arrive early enough to get a seat - there are only 200 seats in the Globe. The session will also be webcast: http://webcast.cern.ch/

  12. Poroelasticity and Poroplasticity At Large Strains Poroélasticité et poro-élastoplasticité en grandes déformations

    Directory of Open Access Journals (Sweden)

    Dormieux L.

    2006-12-01

    Full Text Available This paper reviews some aspects of the formulation of the constitutive behavior of a saturated porous material in isothermal evolutions in the domain of large strains. First, the results concerning the nonporous solid are recalled. Then, the poroelastic and poro-elastoplastic behaviors at large strains are successively considered. When the solid phase is elastic at large strains, a micro-macro approach shows that the free energy of the skeleton is a macroscopic thermodynamic potential. The latter depends on the macroscopic strain of the skeleton and on the lagrangian porosity, which can be interpreted as macroscopic state variables. When the solid is elastoplastic at large strains, a theory of finite poro-elastoplasticity is proposed within a macroscopic thermodynamic framework. The homogenization techniques allow to clarify some aspects of the formulation of the macroscopic behavior. In particular, the validity of the effective stress principle in finite poroelasticity and poroplasticity is established when the solid phase is incompressible. Even if the macroscopic strain applied to an elementary volume is infinitesimal, the strain field at the microscopic scale may not be infinitesimal. Hence, the simulation of the macroscopic behavior of this elementary volume in the framework of a micro-macro approach must take into account possible large strains at the microscopic scale. Cet article examine quelques aspects de la formulation du comportement d'un milieu poreux saturé en évolution isotherme dans le domaine des transformations finies. Après avoir rappelé les résultats propres aux solides non poreux, on s'intéressera successivement aux comportements poroélastique et poro-élastoplastique. Si la phase solide qui constitue le squelette présente un comportement élastique dans le domaine des grandes déformations, un passage micro-macro démontrera que l'énergie libre du squelette constitue un potentiel thermodynamique pour le

  13. Otitis media

    NARCIS (Netherlands)

    Rovers, MM; Schilder, AGM; Zielhuis, GA; Rosenfeld, RM

    2004-01-01

    Otitis media (OM) continues to be one of the most common childhood infections and is a major cause of morbidity in children. The pathogenesis of OM is multifactorial, involving the adaptive and native immune system, Eustachian-tube dysfunction, viral and bacterial load, and genetic and environmental

  14. Social Media

    Science.gov (United States)

    2010-05-01

    Digital Marketing and Ecommerce Professionals. 29 January 2010. 20 May 2010. <http://econsultancy.com/blog/5324-20+-mind-blowing-social- media...Statistics Revisited.” Econsultancy | Community of Digital Marketing and Ecommerce Professionals. 29 Jan. 2010. 20 May 2010. <http://econsultancy.com/blog

  15. Streaming Media

    Science.gov (United States)

    Pulley, John

    2009-01-01

    At a time when the evolutionary pace of new media resembles the real-time mutation of certain microorganisms, the age-old question of how best to connect with constituents can seem impossibly complex--even for an elite institution plugged into the motherboard of Silicon Valley. Identifying the most effective vehicle for reaching a particular…

  16. Determination of Aquifer and Fault Permeabilities by Studying the Poroelastic Response of Rocks Using InSAR in the Upper Coachella Valley Area, CA, USA

    Science.gov (United States)

    Appana, R.; Saar, M. O.

    2007-12-01

    Coachella Valley in California is an area enclosed between Little Bernardino, San Jacinto, and San Bernardino Mountains. The San Andreas Fault system runs through the valley. Satellite interferometry (InSAR) has revealed a differential uplift of the land surface over a period of time across two basin-cutting faults, the Banning Fault (BF) and the Garnet Hill Fault (GHF), in the upper Coachella valley region. This uplift is due to a combined effect of both elastic response of the aquifer due to groundwater recharge at the White Water Spreading Facility and tectonic stresses in the region (Wisely et. al., AGU 2006). In this region, faults appear to act as semi-permeable barriers to groundwater flow (Wisely et. al., AGU 2005). As a result, water levels are not restored uniformly throughout the entire aquifer leading to differential uplift of the land surface. Hence, by developing a numerical model of groundwater flow in this aquifer system, that includes hydraulic representations of the existing faults, a better water management strategy can be achieved which aims at restoring the groundwater levels throughout the aquifer. In addition, the proposed model would better constrain fault permeabilities with implications for research related to earthquake dynamics and assessment of potential slip along segments of the San Andreas Fault system. A finite element code is being used to implement the groundwater flow model. The model simulates the poroelastic response of the faulted aquifer to changing groundwater levels. InSAR data and well data collected in this region will be used to constrain the model yielding parameters such as the hydraulic conductivity field of the aquifer and fault system, storage co-efficients, skeletal compressibilities, and the grounwater influx, and outflux, of the basin.

  17. [Chronic otitis mediaChronic Otitis Media].

    Science.gov (United States)

    Kohles, N; Schulz, T; Eßer, D

    2015-11-01

    There are 2 different kinds of chronic otitis media: Otitis media chronica mesotympanalis and otitis media chronica epitympanalis (cholesteatoma). The incidence of chronic otitis media as reported in literature differs in a wide range. The incidence rates vary between 0.45 and 46%. Both, otitis media chronica mesotympanalis and cholesteatoma, lead to eardrum perforation due to lengthy and recurring inflammations. Furthermore, chronic otitis media is characterized by frequently recurring otorrhea and conductive hearing loss. Georg Thieme Verlag KG Stuttgart · New York.

  18. Praktik Internasionalisasi Media Beritasatu Media Holdings

    OpenAIRE

    Endang SM, Anis

    2015-01-01

    This study aimed to determine the practice of Internationalization carried out by BeritaSatu Media Holdings in supporting global economic interests of Lippo Group Company. Internationalization is an implication of media industrialization which the media company owner sought to reduce the spatial distance to obtain greater profits. Theory of Political Economy Media used to see how media content represents the interests of certain political economy, especially from media owners. To view the pra...

  19. Otitis media with effusion

    Science.gov (United States)

    OME; Secretory otitis media; Serous otitis media; Silent otitis media; Silent ear infection; Glue ear ... Kerschner JE, Preciado D. Otitis media. In: Kliegman RM, Stanton BF, St. ... of Pediatrics . 20th ed. Philadelphia, PA: Elsevier; 2016: ...

  20. Media places

    DEFF Research Database (Denmark)

    Linde, Per; Messeter, Jörn

    are no longer neutral layers in urban living, but rather an integrated part of the materialities of architecture and urban planning, the social dimensions of city life and emerging new cultural frameworks. Arguably, we have reached a point at which digital designs may be regarded as elements of our everyday...... for the Media places project, give some brief insights into the themes of setting up temporary digital streams of media and mobile games. Considering the work-in-progress character of the research and the smaller format of text, no real in-depth analysis will be carried out. The goal is rather to position...... construction of place in the urban setting. The concept of Hertzian space, put forth by Anthony Dunne and others (Dunne, 1999) also carries a dimension of how spaces of wireless communication may be problematized, and how we can criticize cultural phenomena taken for granted through innovative technology. From...

  1. Media matters.

    Science.gov (United States)

    Martinez, L M

    1995-01-01

    The impact of the mass media on woman's status was addressed at two 1995 conferences: the Fourth World Conference on Women, held in Beijing, China, and the Congress of the World Association for Christian Communication, held in Puebla, Mexico. The globalization process facilitated by the mass media has served to increase the power of patriarchy, with no advantages to the cause of women's rights. Coverage of popular movements has been suppressed out of deference to male-controlled governments. Coverage of the Beijing Conference highlighted celebrities and personal stories, to the exclusion of the economic and political issues under debate. Television has commodified women, reinforcing their oppression. On the other hand, the alternative media, which tend to be decentralized, democratic, low-cost, and low in technology, are presenting women as subjects rather than objects and deconstructing gender stereotypes. Of concern, however, is the tendency of computer technology to widen the gap between social classes and developed and developing countries. Women must use information networks to disseminate information on women's rights and strengthen the links between women throughout the world.

  2. Media Education Initiatives by Media Organizations: The Uses of Media Literacy in Hong Kong Media

    Science.gov (United States)

    Chu, Donna; Lee, Alice Y. L.

    2014-01-01

    As more media organizations have engaged in media education, this paper investigates the goals and practices of these activities. This article coins media education initiatives by media organizations with the term "media-organization media literac"y (MOML). Four MOML projects in Hong Kong were selected for examination. Built on critical…

  3. Multi-component pre-stack time-imaging and migration-based velocity analysis in transversely isotropic media; Imagerie sismique multicomposante et analyse de vitesse de migration en milieu transverse isotrope

    Energy Technology Data Exchange (ETDEWEB)

    Gerea, C.V.

    2001-06-01

    Complementary to the recording of compressional (P-) waves, the observation of P-S converted waves has recently been receiving specific attention. This is mainly due to their tremendous potential as a tool for fracture and lithology characterization, imaging sediments in gas saturated rocks, and imaging shallow sediments with higher resolution than conventional P-P data. In a conventional marine seismic survey, we cannot record P-to-S converted-wave energy since the fluids cannot support shear-wave strain. Thus, to capture the converted-wave energy, we need to record it at the water-bottom casing an ocean-bottom cable (OBC). The S-waves recorded at the seabed are mainly converted from P to S (i.e., PS-waves or C-waves) at the subsurface reflectors. The most accurate way to image seismic data is pre-stack depth migration. In this thesis, I develop a numerically efficient 2.5-D true-amplitude elastic Kirchhoff pre-stack migration algorithm designed to handle OBC data gathered along a single line. All the kinematic and dynamic elastic Green's functions required in the computation of true-amplitude weight term of Kirchhoff summation, are based on the non-hyperbolic explicit approximations of P- and SV-wave travel-times in layered transversely isotropic (VTI) media. Hence, this elastic imaging algorithm is very well-suited for migration-based velocity analysis techniques, for which fast, robust and iterative pre-stack migration is desired. In this thesis, I approach also the topic of anisotropic velocity model building for elastic pre-stack time-imaging. and propose an original methodology for joint PP-PS migration-based velocity analysis (MVA) in layered VTI anisotropic media. Tests on elastic synthetic and real OBC seismic data ascertain the validity of the pre-stack migration algorithm and velocity analysis methodology. (author)

  4. Critical media pedagogy - theoretical underpinning and contribution to media education

    OpenAIRE

    Valenta, Petr

    2016-01-01

    Critical media pedagogy - theoretical underpinnigs and contribution to media education Dissertation Mgr. Petr Valenta Keywords critical theory, critical media pedagogy, media literacy, critical pedagogy, media, ideology, discourse, power, symbolic power, knowledge Abstract The theoretical dissertation analyzes the traditional media education model issues, which derives from the orientation of media literacy on the dominant paradigm of media effects research in media studies. Media education t...

  5. The Al Hoceima earthquake sequence of 1994, 2004 and 2016: Stress transfer and poroelasticity in the Rif and Alboran Sea region

    Science.gov (United States)

    Kariche, J.; Meghraoui, M.; Timoulali, Y.; Cetin, E.; Toussaint, R.

    2018-01-01

    The 2016 January 25 earthquake (Mw 6.3) follows in sequence from the1994 May 26 earthquake (Mw 6.0) and the 2004 February 24 earthquake (Mw 6.4) in the Rif Mountains and Alboran Sea. The earlier two seismic events which were destructive took place on inland conjugate faults, and the third event occurred on an offshore fault. These earthquake sequences occurred within a period of 22 yr at ˜25 km distance and 11-16-km depth. The three events have similar strike-slip focal mechanism solutions with NNE-SSW trending left-lateral faulting for the 1994 and 2016 events and NW-SE trending right-lateral faulting for the 2004 event. This shallow seismic sequence offers the possibility (i) to model the change in Coulomb Failure Function (ΔCFF with low μ΄ including the pore pressure change) and understand fault-rupture interaction, and (ii) to analyse the effect of pore fluid on the rupture mechanism, and infer the clock-time advance. The variation of static stress change has a direct impact on the main shock, aftershocks and related positive lobes of the 2004 earthquake rupture with a stress change increase of 0.7-1.1 bar. Similarly, the 2004 main shock and aftershocks indicate loading zones with a stress change (>0.25 bar) that includes the 2016 earthquake rupture. The tectonic loading of 19-24 nanostrain yr-1 obtained from the seismicity catalogue of Morocco is comparable to the 5.0 × 1017 N.m yr-1 seismic strain release in the Rif Mountains. The seismic sequence is apparently controlled by the poroelastic properties of the seismogenic layer that depend on the undrained and drained fluid conditions. The short interseismic period between main shocks and higher rate of aftershocks with relatively large magnitudes (4 < Mw < 5.5) implies the pore-fluid physical effect in undrained and drained conditions. The stress-rate ranges between 461 and 582 Pa yr-1 with a ΔCFF of 0.2-1.1 bar. The computed clock-time advance reaches 239 ± 22 yr in agreement with the ˜10 yr delay

  6. Managing Media: Segmenting Media Through Consumer Expectancies

    Directory of Open Access Journals (Sweden)

    Matt Eastin

    2014-04-01

    Full Text Available It has long been understood that consumers are motivated to media differently. However, given the lack of comparative model analysis, this assumption is without empirical validation, and thus, the orientation of segmentation from a media management perspective is without motivational grounds. Thus, evolving the literature on media consumption, the current study develops and compares models of media segmentation within the context of use. From this study, six models of media expectancies were constructed so that motivational differences between media (i.e., local and national newspapers, network and cable television, radio, and Internet could be observed. Utilizing higher order statistical analyses the data indicates differences across a model comparison approach for media motivations. Furthermore, these differences vary across numerous demographic factors. Results afford theoretical advancement within the literature of consumer media consumption as well as provide media planners’ insight into consumer choices.

  7. Geographic Media Literacy

    Science.gov (United States)

    Lukinbeal, Chris

    2014-01-01

    While the use of media permeates geographic research and pedagogic practice, the underlying literacies that link geography and media remain uncharted. This article argues that geographic media literacy incorporates visual literacy, information technology literacy, information literacy, and media literacy. Geographic media literacy is the ability…

  8. Measuring News Media Literacy

    Science.gov (United States)

    Maksl, Adam; Ashley, Seth; Craft, Stephanie

    2015-01-01

    News media literacy refers to the knowledge and motivations needed to identify and engage with journalism. This study measured levels of news media literacy among 500 teenagers using a new scale measure based on Potter's model of media literacy and adapted to news media specifically. The adapted model posits that news media literate individuals…

  9. The Mass Media Book.

    Science.gov (United States)

    Holmgren, Rod, Ed.; Norton, William, Ed.

    This anthology consists of two major sections, "The News Media" and "The Entertainment Media." Both feature essays by critics, working professionals, and professional observers of the media. One aim of the anthology is to show the pervasive effect of the media on us. The section on news media comments on such topics as credibility gap, Vice…

  10. Media Pembelajaran Global Warming

    OpenAIRE

    Tham, Fikri Jufri; Liliana, Liliana; Purba, Kristo Radion

    2016-01-01

    Computer based learning media is one of the media has an important role in learning. Learning media will be attractive when packaged through interactive media , such as interactive media created in paper manufacture " instructional media global warming" . The advantage gained is that it can increase knowledge, generally educate people to be more concerned about the environment , and also can be a means of entertainment. This application is focused to learn about global warming and packaged in...

  11. Social media metrics

    OpenAIRE

    Balvín, Radek

    2013-01-01

    With growing amount of data produced by users on social media the need of extraction of relevant data for marketing, research and other uses grows as well. The bachelor thesis named "Social media metrics" presents the issues of monitoring, measurement and metrics of social media. In the research part it also maps and captures the present Czech practice in measurement and monitoring of social media. I also rate the use of social media monitoring tools and usual methods of social media measurem...

  12. Social media management and media environment

    Directory of Open Access Journals (Sweden)

    Šiđanin Iva

    2012-01-01

    Full Text Available The paper deals with the system of services that social media management can offer to a variety of users. As social media systems are emerging, social media management can strengthen teams in social media and help to manage numerous social channels and distribution of social information from one place. Social media management is a system of procedures that are used to manage the flow of information in the environment of social media. This involves connecting with social media like Facebook, Twitter, LinkedIn, Plaxo, Ecademy, YouTube and many others, then the aggregation and management of social data. Social media management services are analysed through various fields, such as managing multiple social media profiles, mail scheduling and filtering, reporting and analytics. Social media management enables managing personal business through social media, which contributes to a significant reduction in expenditures. The paper also discusses the importance of social media management in marketing activities and various forms of social promotion, which allow companies to easily reach their customers.

  13. Konservasi Media: Memori Kultural pada Media-Media Lama

    Directory of Open Access Journals (Sweden)

    Aloysius Ranggabumi Nuswantoro

    2015-01-01

    Full Text Available Abstract: Technology boosts the emergence of new communication tools and also creates the dichotomy of old media and new media. At first, it seems like there is nothing wrong with the dichotomy. However, in the context of communication value and meaning, there may be something missing when old media are being abandoned. Not merely the physical manifestation of old media, but rather the work it that contains useful information for the current generation. As a result, today’s people are now losing the root of their thoughts in the past. Thus, conservation is frankly needed to preserve the cultural memory in society Abstrak: Teknologi mendorong munculnya alat-alat komunikasi baru dan membuat dikotomi media lama dan media baru. Sekilas tidak ada yang salah dengan dikotomi tersebut dan konsekuensi yang menyertainya. Namun dalam konteks nilai dan makna komunikasi, ada sesuatu yang hilang ketika media lama ditinggalkan. Bukan semata-mata pada perwujudan fisik media lama, tetapi lebih kepada karya media lama yang memuat informasi berguna bagi generasi saat itu. Akibatnya orang zaman kini kehilangan jejak atau akar pikiran mereka di masa lalu. Maka konservasi media perlu dilakukan untuk mempertahankan memori kultural tersebut.

  14. EFEKTIVITAS MEDIA DALAM PEMBELAJARAN

    Directory of Open Access Journals (Sweden)

    Anjar Sri Wahyuni

    2015-12-01

    Full Text Available Advances in technology in various fields, for example in communications and information technology at the moment, learning media has a central position in the learning process and not solely aids. The media is an integral part of the learning process. In this process, using instructional media associated with anything that can be done by the media. Instructional media used in learning activities can influence the learning efektitas. At first, learning media only serves as a tool for teachers. Two approaches / models of learning media in the electoral process, namely: selecting the model enclosed and open selection model. Closed election occurs when alternative media has been determined. Open selection model is the inverse of the secret ballot. We are still free to choose any type of media, according to our needs. Alternative media is still wide open. Choose open procedures more flexible in nature, because really we adjust to the needs and conditions.   Keywords :  Effectiveness, Media, Learning.

  15. Konservasi Media: Memori Kultural pada Media-Media Lama

    OpenAIRE

    Aloysius Ranggabumi Nuswantoro

    2015-01-01

    Abstract: Technology boosts the emergence of new communication tools and also creates the dichotomy of old media and new media. At first, it seems like there is nothing wrong with the dichotomy. However, in the context of communication value and meaning, there may be something missing when old media are being abandoned. Not merely the physical manifestation of old media, but rather the work it that contains useful information for the current generation. As a result, today’s people are now l...

  16. Konservasi Media: Memori Kultural Pada Media-Media Lama

    OpenAIRE

    Nuswantoro, Aloysius Ranggabumi

    2014-01-01

    : Technology boosts the emergence of new communication tools and also creates the dichotomy of old media and new media. At first, it seems like there is nothing wrong with the dichotomy. However, in the context of communication value and meaning, there may be something missing when old media are being abandoned. Not merely the physical manifestation of old media, but rather the work it that contains useful information for the current generation. As a result, today’s people are now losing th...

  17. Media Violence and Children.

    Science.gov (United States)

    Groebel, Jo

    1998-01-01

    Presents the results of the UNESCO global study on media violence and children which was conducted between 1996 and 1997. Highlights include the role of the media, media heroes as role models, media violence and aggression, differences by gender, rural versus urban environments, the pervasiveness of television, and recommendations. (Author/LRW)

  18. Living within the Media

    Science.gov (United States)

    Griffin, Erin

    2005-01-01

    In this article, the author shares how media affects her as a teenager. The author says that media has such a relationship with the world today, specifically with teenagers like her. Media gives off so much information that can be valid or invalid, positive or negative. The media can persuade anyone to do something or to think a certain way.…

  19. The Media Teacher's Handbook

    Science.gov (United States)

    Scarratt, Elaine, Ed.; Davison, Jon, Ed.

    2011-01-01

    "The Media Teacher's Handbook" is an indispensible guide for all teachers, both specialist and non-specialist, delivering Media Studies and media education in secondary schools and colleges. It is the first text to draw together the three key elements of secondary sector teaching in relation to media study--the "theoretical",…

  20. 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…

  1. Efektivitas Media Dalam Pembelajaran

    Directory of Open Access Journals (Sweden)

    Anjar Sri Wahyuni

    2015-03-01

    Full Text Available Advances in technology in various fields, for example in communications and information technology at the moment, learning media has a central position in the learning process and not solely aids. The media is an integral part of the learning process. In this process, using instructional media associated with anything that can be done by the media. Instructional media used in learning activities can influence the learning efektitas. At first, learning media only serves as a tool for teachers. Two approaches / models of learning media in the electoral process, namely: selecting the model enclosed and open selection model. Closed election occurs when alternative media has been determined. Open selection model is the inverse of the secret ballot. We are still free to choose any type of media, according to our needs. Alternative media is still wide open. Choose open procedures more flexible in nature, because really we adjust to the needs and conditions.

  2. Ethics of Media

    OpenAIRE

    2013-01-01

    Events such as the phone-hacking scandal, Wikileaks and the Mohammed cartoons controversy have placed ethics of media at the centre of current debates. Media are not only centralised institutions, but also technologies and means through which we sustain relationships with each other. We live with and in media, and this book sketches and critiques the normative contours of our intensely mediated worlds. What are the 'ethics' of media? What forms would we expect them to take? Do digital media c...

  3. Social media influencer marketing

    OpenAIRE

    Isosuo, Heli

    2016-01-01

    The marketing field is changing simultaneously with the digital world. Social media is getting more and more important to marketers, and there is a need to stand out in the social media noise. Social media influencer marketing could be a good alternative to other types of marketing. A need from the consignor and the interest of the author were the motivations for conducting the study. Sääskilahti Consulting has a social media influencer network Somevaikuttajat, which is offering social media ...

  4. Media Pluralism and Diversity

    DEFF Research Database (Denmark)

    challenges for media pluralism policies in the light of a fast changing media environment. The book is unique in that it confronts insights from all parts of the world and from a broad range of disciplines including law, economics, media studies, and sociology.......In the western world, a diverse and pluralistic media landscape is deemed essential for democracy. But how universal is media pluralism as a concept underpinning media policies? To what extent do normative approaches, regulatory dimensions and monitoring systems differ throughout the world......? Adopting a truly global, theoretical and multidisciplinary perspective, Media Pluralism and Diversity advances our understanding of media pluralism across the globe. It compares metrics developed in different parts of the world to assess levels of, or threats to, media pluralism. It identifies common...

  5. Unpacking New Media Literacy

    Directory of Open Access Journals (Sweden)

    Der-Thanq “victor” Chen

    2011-04-01

    Full Text Available The 21st century has marked an unprecedented advancement of new media. New media has become so pervasive that it has penetrated into every aspect of our society. New media literacy plays an essential role for any citizen to participate fully in the 21st century society. Researchers have documented that literacy has evolved historically from classic literacy (reading-writing-understanding to audiovisual literacy to digital literacy or information literacy and recently to new media literacy. A review of literature on media literacy reveals that there is a lack of thorough analysis of unique characteristics of new media and its impacts upon the notion of new media literacy. The purpose of the study is to unpack new media literacy and propose a framework for a systematic investigation of new media literacy.

  6. Parenting and Digital Media.

    Science.gov (United States)

    Coyne, Sarah M; Radesky, Jenny; Collier, Kevin M; Gentile, Douglas A; Linder, Jennifer Ruh; Nathanson, Amy I; Rasmussen, Eric E; Reich, Stephanie M; Rogers, Jean

    2017-11-01

    Understanding the family dynamic surrounding media use is crucial to our understanding of media effects, policy development, and the targeting of individuals and families for interventions to benefit child health and development. The Families, Parenting, and Media Workgroup reviewed the relevant research from the past few decades. We find that child characteristics, the parent-child relationship, parental mediation practices, and parents' own use of media all can influence children's media use, their attitudes regarding media, and the effects of media on children. However, gaps remain. First, more research is needed on best practices of parental mediation for both traditional and new media. Ideally, this research will involve large-scale, longitudinal studies that manage children from infancy to adulthood. Second, we need to better understand the relationship between parent media use and child media use and specifically how media may interfere with or strengthen parent-child relationships. Finally, longitudinal research on how developmental processes and individual child characteristics influence the intersection between media and family life is needed. The majority of children's media use takes place within a wider family dynamic. An understanding of this dynamic is crucial to understanding child media use as a whole. Copyright © 2017 by the American Academy of Pediatrics.

  7. Mass Media: The Invisible Environment.

    Science.gov (United States)

    Glessing, Robert J.; White, William P.

    This anthology for students of media consists of essays and articles grouped under four topics: media forms, media content, media environments, and "the last word." Media forms deals with the nature of these kinds of media: electronic, print, film, music, and comics, graffiti, and clothing. Media content contains articles on the news, advertising,…

  8. Social Media Reputation

    DEFF Research Database (Denmark)

    Etter, Michael Andreas; Ravasi, Davide; Colleoni, Elanor

    Social media enable millions of users to create and disseminate narratives about organizations that increase their public exposure and shape public perceptions. In this paper, we draw on the sociology of news production and research on computer-mediated communication to discuss how different...... motivational drivers and contextual conditions associated with the formation of narratives in traditional news media and social media influence their content, diffusion, and impact significantly. Our analysis suggests that current theories of media reputation may provide an incomplete representation...... of the phenomenon, and highlight theoretically relevant differences and interrelationships between reputational dynamics involving news media and social media....

  9. AMAMM - All Media Are Mixed Media

    DEFF Research Database (Denmark)

    All Media Are Mixed Media Alle medier er blandingsmedier. Alle kunstarter er kompositte. Alle sanser er sammensatte. Alle medialiteter er miksede og mangfoldige. Alle er AMAMM. Denne påstand står centralt i ord-, billed- og medie-teoretikeren W.J.T. Mitchells forfatterskab. I hosstående bog tager...

  10. Homogenization of a double porosity model in deformable media

    Directory of Open Access Journals (Sweden)

    Abdelhamid Ainouz

    2013-04-01

    Full Text Available The article addresses the homogenization of a family of micro-models for the flow of a slightly compressible fluid in a poroelastic matrix containing periodically distributed poroelastic inclusions, with low permeabilities and with imperfect contact on the interface. The micro-models are based on Biot's system for consolidation processes in each phase, with interfacial barrier formulation. Using the two-scale convergence technique, it is shown that the derived system is a general model of that proposed by Aifantis, plus an extra memory term.

  11. The social media revolution.

    Science.gov (United States)

    Dubose, Cheryl

    2011-01-01

    The growing popularity and use of social media tools such as Facebook, YouTube, Twitter, blogging, and wikis have led to a social media revolution. Given this widespread influence, it is important for educators, administrators, and technologists to understand the risks of using social media in the classroom and workplace. To investigate popular social media sites and their effect on radiologic technology education and business practices. A comprehensive search of literature was performed to examine social media and its applications in education, health care, and business. Social media use is on the rise, affecting all aspects of mainstream society. Leaders in the radiologic sciences should be familiar with social media and cognizant of its risks. Future studies regarding social media use in the radiologic sciences are necessary to determine its effect on the radiologic science community. ©2011 by the American Society of Radiologic Technologists.

  12. Learning Media Programme

    NARCIS (Netherlands)

    Westera, Wim

    2009-01-01

    Westera, W. (2009). Learning Media Programme. Introductory presentation of Learning Media Programme for visitors of Kavala University of Technology, Kavala, Greece and National Institute of Multimedia Education, Chiba, Japan. March, 2, 2009, Heerlen, The Netherlands.

  13. Der Social Media Bibliothekar

    OpenAIRE

    Danowski, Patrick

    2012-01-01

    Social Media became an inherent part of our daily lives. Librarians are obliged to learn how to deal with these new media types in the same way as they had always adapted to new developments in the past.

  14. Introduction to social media.

    Science.gov (United States)

    Meru, Michael

    2012-01-01

    This overview of social media categories some of the typical types and uses of this form of communication and suggests common courtesies and effective strategies for participation in the social media culture.

  15. Trends in Media Use

    National Research Council Canada - National Science Library

    Donald F. Roberts; Ulla G. Foehr

    2008-01-01

    .... Donald Roberts and Ulla Foehr examine how both media use and media exposure vary with demographic factors such as age, race and ethnicity, and household socioeconomic status, and with psychosocial...

  16. MODERN MEDIA EDUCATION MODELS

    Directory of Open Access Journals (Sweden)

    Alexander Fedorov

    2011-03-01

    Full Text Available The author supposed that media education models can be divided into the following groups:- educational-information models (the study of the theory, history, language of media culture, etc., based on the cultural, aesthetic, semiotic, socio-cultural theories of media education;- educational-ethical models (the study of moral, religions, philosophical problems relying on the ethic, religious, ideological, ecological, protectionist theories of media education;- pragmatic models (practical media technology training, based on the uses and gratifications and ‘practical’ theories of media education;- aesthetical models (aimed above all at the development of the artistic taste and enriching the skills of analysis of the best media culture examples. Relies on the aesthetical (art and cultural studies theory; - socio-cultural models (socio-cultural development of a creative personality as to the perception, imagination, visual memory, interpretation analysis, autonomic critical thinking, relying on the cultural studies, semiotic, ethic models of media education.

  17. Media and Risky Behaviors

    National Research Council Canada - National Science Library

    Soledad Liliana Escobar-Chaves; Craig A. Anderson

    2008-01-01

    .... First, the authors note that U.S. youth are spending increasing amounts of time using electronic media, with the average American youngster now spending one-third of each day with some form of electronic media...

  18. Media and Crime

    DEFF Research Database (Denmark)

    Agger, Gunhild; Waade, Anne Marit

    2011-01-01

    Recent developments in the relationship between media and crime are analyzed, taking both fiction and journalism in account......Recent developments in the relationship between media and crime are analyzed, taking both fiction and journalism in account...

  19. On the Role of Osmosis for Non-Linear Shock Waves f Pressure and Solute in Porous Media

    Science.gov (United States)

    Kanivesky, Roman; Salusti, Ettore; Caserta, Arrigo

    2013-04-01

    A novel non-Osanger model focusing on non-linear mechanic and chemo-poroelastic coupling of fluids and solute in porous rocks is developed based on the modern wave theory. Analyzing in 1-D a system of two adjacent rocks with different conditions we obtain two coupled non-linear equations for fluid pressure and solute (salt or pollutants) concentration, evolving under the action of strong stress from one "source" rock towards the other rock. Their solutions allow to identify quick non-linear solitary (Burgers) waves of coupled fluid pressure and solute density, that are different from diffusive or perturbative solutions found in other analyses. The strong transient waves for low permeability porous media, such as clay and shale, are analyzed in detail. For medium and high-permeability porous media (sandstones) this model is also tentatively applied. Indeed in recent works of Alexander (1990) and Hart(2009) is supported the presence of small osmotic phenomena in other rocks where osmosis was previously ignored. An attempt to apply our model to soils in Calabria (Italy), such as clastic marine and fluvial deposits as well as discontinuous remnants of Miocene and Pliocene carbonate and terrigeneous deposits, is also discussed.

  20. Trends in media use.

    Science.gov (United States)

    Roberts, Donald F; Foehr, Ulla G

    2008-01-01

    American youth are awash in media. They have television sets in their bedrooms, personal computers in their family rooms, and digital music players and cell phones in their backpacks. They spend more time with media than any single activity other than sleeping, with the average American eight- to eighteen-year-old reporting more than six hours of daily media use. The growing phenomenon of "media multitasking"--using several media concurrently--multiplies that figure to eight and a half hours of media exposure daily. Donald Roberts and Ulla Foehr examine how both media use and media exposure vary with demographic factors such as age, race and ethnicity, and household socioeconomic status, and with psychosocial variables such as academic performance and personal adjustment. They note that media exposure begins early, increases until children begin school, drops off briefly, then climbs again to peak at almost eight hours daily among eleven- and twelve-year-olds. Television and video exposure is particularly high among African American youth. Media exposure is negatively related to indicators of socioeconomic status, but that relationship may be diminishing. Media exposure is positively related to risk-taking behaviors and is negatively related to personal adjustment and school performance. Roberts and Foehr also review evidence pointing to the existence of a digital divide--variations in access to personal computers and allied technologies by socioeconomic status and by race and ethnicity. The authors also examine how the recent emergence of digital media such as personal computers, video game consoles, and portable music players, as well as the media multitasking phenomenon they facilitate, has increased young people's exposure to media messages while leaving media use time largely unchanged. Newer media, they point out, are not displacing older media but are being used in concert with them. The authors note which young people are more or less likely to use several

  1. Children and the Media

    OpenAIRE

    Dennis, Everette E.; Pease, Edward C.

    1996-01-01

    Throughout history the media has primarily been produced by adults, for adults, about adults. Increasingly, children have become a matter of high priority in the modern media society, and as they have, they have also become the subject of much concern. From debates in Congress about the detrimental effects of movies, comic books, and video games over the last century to efforts to court children as media consumers, there is a clear recognition that the media are not now and probably ne...

  2. Advertising on social media

    OpenAIRE

    Sumit Goyal

    2013-01-01

    This communication reports the latest trends of advertising on social media. Social media advertising means to gain traffic or attention of online users through social media sites. Today, when a user thinks about buying something, he first comes to the internet, searches for that product, compares its price with other competing brands and takes a decision, which one to buy. In this write-up, author has discussed many aspects concerning advertising through social media, viz., what is social me...

  3. Asian Media Productions

    DEFF Research Database (Denmark)

    This work consists of 12 essays on different aspects of Asian media by Japanese, European, and American scholars, many of whom have themselves been involved in the production of media forms. Working in the fields of anthropology, media and cultural studies, and on the basis of hands-on research......, they have written a book on the social practices and cultural attitudes of people producing, reading, watching and listening to different kinds of media in Japan, China, Taiwan, Indonesia, Vietnam, Singapore and India....

  4. Oriented Fiber Filter Media

    OpenAIRE

    R. Bharadwaj; A. Patel, S. Chokdeepanich, Ph.D.; G.G. Chase, Ph.D.

    2008-01-01

    Coalescing filters are widely used throughout industry and improved performance will reduce droplet emissions and operating costs. Experimental observations show orientation of micro fibers in filter media effect the permeability and the separation efficiency of the filter media. In this work two methods are used to align the fibers to alter the filter structure. The results show that axially aligned fiber media improve quality factor on the order of 20% and cutting media on an angle from a t...

  5. Hogeschooldocenten op social media

    NARCIS (Netherlands)

    Marjorie Louwsma; Ingeborg van Dorth; Erwin Kuipers; Klaas Jan Huizing

    2013-01-01

    Dat studenten grootgebruikers zijn van social media wisten we al na ons onderzoek Wat studenten doen op social media. Maar hoe staat dat met docenten aan de hogeschool? Liggen er kansen voor educatieve instellingen om social media grootschalig(er) in het onderwijs in te zetten?

  6. Media, Minds, and Masses.

    Science.gov (United States)

    Baggot, James; Vino, Faith

    This booklet describes the language arts course "Media, Minds, and Masses," written for the Dade County, Fla., public schools. Topics for the course include the workings of contemporary radio, television, newspapers, magazines, and movies; the present status and power of media; the history and development of media; and the influences of…

  7. Media and child development

    NARCIS (Netherlands)

    Piotrowski, J.T.; Vossen, H.G.M.; Valkenburg, P.M.; Wright, J.D.

    2015-01-01

    Decades of research have shown that the relationship between media and childhood is not unidirectional but reciprocal. In this article, both directions of the media-child development relationship are presented. We discuss how child development predisposes children's media use and preferences by

  8. Social Media Empowerment (I)

    NARCIS (Netherlands)

    A. Cox

    2011-01-01

    full text via link. Social media stellen mensen, merken en bedrijven in staat om zichzelf te versterken. Soms wordt optimaal gebruik gemaakt van Social Media Empowerment, maar soms ook wat minder. Effectief inzetten van social media. Regel 1: Start met context en motivatie

  9. Youth Media and Agency

    Science.gov (United States)

    Hauge, Chelsey

    2014-01-01

    This article addresses how capacity is conceived of and understood in youth media/civic education programming, and how beliefs about agency, development, relationality and youth manifests in the discourses, programmes, and practices of organizations operating youth media programmes. Through attention to a youth media and development programme in…

  10. The Media Reader.

    Science.gov (United States)

    Valdes, Joan; Crow, Jeanne

    An anthology of readings in the media correlates chapter-by-chapter to the authors' textbook, "The Media Works." Fifteen chapters cover the study of newspapers, magazines, comics, popular music, television, movies, and advertising. The authors included represent varied perspectives on the media. The selections were chosen with the help of a…

  11. Youth media lifestyles

    NARCIS (Netherlands)

    van Kruistum, Claudia; Leseman, Paul Pm; de Haan, Mariëtte

    2014-01-01

    In this article, the concept of "media lifestyles" is adopted in order to develop a comprehensive approach toward youth engagement in communication media. We explore how 503 Dutch eighth grade students with full access to new technology combine a broad range of media by focusing on their engagement

  12. Modern Media Education Models

    Science.gov (United States)

    Fedorov, Alexander

    2011-01-01

    The author supposed that media education models can be divided into the following groups: (1) educational-information models (the study of the theory, history, language of media culture, etc.), based on the cultural, aesthetic, semiotic, socio-cultural theories of media education; (2) educational-ethical models (the study of moral, religions,…

  13. Sizing Up Social Media

    Science.gov (United States)

    Pearson, Jerold

    2010-01-01

    Most people are aware of the increasing importance of social media to institutional advancement, and many colleges and universities have started investing resources in these media. The next step is to measure the impact of social media on the institution and evaluate the success of one's efforts. Every advancement leader should understand how…

  14. Managing Media Workers

    NARCIS (Netherlands)

    Deuze, M.; Lowe, G.F.; Brown, C.

    2015-01-01

    People are more involved with media than ever but news about media as an industry is less than optimistic. The number of people across the creative industries who are losing jobs illustrates all too well. Media managers seem at a loss in developing survival strategies, and specifically in organizing

  15. Reverse-time Migration in Tilted Transversely Isotropic Media with Decoupled Equations

    KAUST Repository

    Zhan, Ge

    2012-12-01

    Conventional modeling and migration for tilted transversely isotropic (TTI) media may suffer from numerical instabilities and shear wave artifacts due to the coupling of the P-wave and SV-wave modes in the TTI coupled equations. Starting with the separated P- and SV-phase velocity expressions for vertical transversely isotropic (VTI) media, I extend these decoupled equations for modeling and reverse-time migration (RTM) in acoustic TTI media. Compared with the TTI coupled equations published in the geophysical literature, the new TTI decoupled equations provide a more stable solution due to the complete separation of the P-wave and SV-wave modes. The pseudospectral (PS) method is the most convenient method to implement these equations due to the form of wavenumber expressions and has the added benefit of being highly accurate and thus avoiding numerical dispersion. The rapid expansion method (REM) in time is employed to produce a broad band numerically stable time evolution of the wavefields. Synthetic results validate the proposed TTI decoupled equations and show that modeling and RTM in TTI media with the decoupled P-wave equation remain numerically stable even for models with strong anisotropy and sharp contrasts. The most desirable feature of the TTI decoupled P-wave equation is that it is absolutely free of shear-wave artifacts and the consequent alleviation of numerical instabilities generally suffered by some systems of coupled equations. However, due to several forward-backward Fourier transforms in wavefield extrapolation at each time step, the computational cost is also high, and thereby hampers its prevalence. I hereby propose to use a hybrid pseudospectral and finite-difference (FD) scheme to solve the TTI decoupled P-wave equation. In the hybrid solution, most of the cost-consuming wavenumber terms in the equation are replaced by inexpensive FD operators, which in turn accelerates the computation and reduces the computational cost. To demonstrate the

  16. Notes for media reinvention

    Directory of Open Access Journals (Sweden)

    Jesús Miguel Flores-Vivar

    2009-10-01

    Full Text Available Journalism and media are going through a change of era. This change is reflected in the transformation of journalism and media-lived and that another major in 1980 that became known as mediamorphosis, by this, professionals have to learn new roles. The impact of information technology and Internet has changed the way how you present the news and, most importantly, transform the business model that has characterized media companies. This article analyzes the current situation provides some strategic guidelines to be followed by some media-and-do and studied some of the new profiles arebeginning to emerge as a result of the reinvention of journalism and the media.

  17. The Concept of Media

    OpenAIRE

    Schmid, Beat

    1997-01-01

    Internet as a synonyme of the"new media" not only contains and disseminates information worldwide - like electronic broadcast media - , it is also capable of processing information in an interactive manner, since it is computer-based, i.e., its information objects are virtual machines. Thus, the potential of the new media is urging us to reconsider the notion of media. Since we witness that formal logic is constituting the concept of the computer, we need a new model of"media" to describe, un...

  18. Social media visibility

    DEFF Research Database (Denmark)

    Uldam, Julie

    2017-01-01

    As activists move from alternative media platforms to commercial social media platforms, they face increasing challenges in protecting their online security and privacy. While government surveillance of activists is well-documented in scholarly research and the media, corporate surveillance...... for responding to the activities of individual activists in social media. It shows that while social media afford an unprecedented level of visibility for activists, it comes with the risk of being monitored by corporations. Theoretically, it draws on conceptions of visibility in social sciences and media...... studies as well as literature on activism and political participation in media studies. Empirically, it draws on files from BP on specific civil society individuals obtained through Subject Access Requests under the UK Data Protection Act 1998 as well as press responses from BP....

  19. Comprehension of digital media

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ju Hwan

    2008-11-15

    This book is divided four parts. The first part describes media and mark on sign and media, what is the sign?, interpretation of sign and semiotics. The second part is for production sign theory and origin of digital revolution such as the problem of origin of digital revolution, homogeneity of producing goods and sign : triple triangle model for production sign theory, triple triangle model for producing goods, triple triangle model of producing sign and triple triangle model of art works. The third parts deals with development of the media and meaning of digital revolution with four changes : invention of letter, appearance of printed media and establishment modernity, appearance electronic media and mess media and appearance of digital media. The last part mentions ontology of world wide web.

  20. Media:Time card stack

    NARCIS (Netherlands)

    Annemarie Wennekers; Jos de Haan; Frank Huysmans

    2016-01-01

    Original title: Media:Tijd in kaart The Dutch spend a daily average of 8 hours 33 minutes using media. Men and people aged over 50 spend most time using media, at an average of 9 hours per day. Older media users prefer traditional media and devices over new media and modern devices. Young and

  1. Understanding Social Media Logic

    Directory of Open Access Journals (Sweden)

    José van Dijck

    2013-08-01

    Full Text Available Over the past decade, social media platforms have penetrated deeply into the mech­anics of everyday life, affecting people's informal interactions, as well as institutional structures and professional routines. Far from being neutral platforms for everyone, social media have changed the conditions and rules of social interaction. In this article, we examine the intricate dynamic between social media platforms, mass media, users, and social institutions by calling attention to social media logic—the norms, strategies, mechanisms, and economies—underpin­ning its dynamics. This logic will be considered in light of what has been identified as mass me­dia logic, which has helped spread the media's powerful discourse outside its institutional boundaries. Theorizing social media logic, we identify four grounding principles—programmabil­ity, popularity, connectivity, and datafication—and argue that these principles become increas­ingly entangled with mass media logic. The logic of social media, rooted in these grounding principles and strategies, is gradually invading all areas of public life. Besides print news and broadcasting, it also affects law and order, social activism, politics, and so forth. Therefore, its sustaining logic and widespread dissemination deserve to be scrutinized in detail in order to better understand its impact in various domains. Concentrating on the tactics and strategies at work in social media logic, we reassess the constellation of power relationships in which social practices unfold, raising questions such as: How does social media logic modify or enhance ex­isting mass media logic? And how is this new media logic exported beyond the boundaries of (social or mass media proper? The underlying principles, tactics, and strategies may be relat­ively simple to identify, but it is much harder to map the complex connections between plat­forms that distribute this logic: users that employ them, technologies that

  2. On a model simulating lack of hydraulic connection between a man-made reservoir and the volume of poroelastic rock hosting the focus of a post-impoundment earthquake

    Science.gov (United States)

    Chander, Ramesh; Tomar, S. K.

    2016-12-01

    The idea that a direct hydraulic connection between a man-made reservoir and the foci of post-impoundment earthquakes may not exist at all sites is eminently credible on geological grounds. Our aim is to provide a simple earth model and related theory for use during investigations of earthquakes near new man-made reservoirs. We consider a uniform circular reservoir which rests on the top surface of a no-hydraulic-connection earth model (NHCEM). The model comprises a top elastic (E) layer, an intermediate poroelastic (P) layer, and a bottom elastic half space. The focus of a potential earthquake in the P layer is located directly under the reservoir. The E layer disrupts the hydraulic connection between the reservoir and the focus. Depth of water in the reservoir varies as H ' + hcos( ω t). Expressions for reservoir-induced stresses and pore pressure in different layers of the NHCEM are obtained by solving the boundary-value problem invoking full coupling between mean normal stress and pore pressure in the P layer. As an application of the derived mathematical results, we have examined and found that earthquakes on 60∘ normal faults may occur in the P-layer of a selected NHCEM at epochs of low reservoir level if the reservoir lies mostly in the footwall of the fault. The exercise was motivated by observations of such earthquakes under the man-made Lake Mead after it was impounded.

  3. Media education and media enlightenment as attributes of information society

    Directory of Open Access Journals (Sweden)

    Лилия Борисовна Белоглазова

    2014-12-01

    Full Text Available The article deals with the problem of the functioning of media-education and media-enlightenment in modern society. Focuses on the impact of this socio-cultural phenomenon on consciousness of members of the Information Society. Are the main characteristics of media-education and media-education and media-enlightenment. Concludes that media-education and media-enlightenment forms unscientific and anti-scientific thinking and style speech.

  4. Media relations after the introduction of social media

    OpenAIRE

    Mesila, Helin

    2010-01-01

    In the light of the popularity of social media on one hand, and the contradictive relationships between journalists and public relations practitioners on the other hand, the thesis studies media relations after the introduction of social media. The study focuses on media relations in Estonian public relations scenery. The research answers to the questions: - What are media relations today? - What are the functions of social media and media relations in organizational communication? ...

  5. Abortion in the media.

    Science.gov (United States)

    Conti, Jennifer A; Cahill, Erica

    2017-12-01

    To review updates in how abortion care is depicted and analysed though various media outlets: news, television, film, and social media. A surge in recent media-related abortion research has recognized several notable and emerging themes: abortion in the news media is often inappropriately sourced and politically motivated; abortion portrayal in US film and television is frequently misrepresented; and social media has a new and significant role in abortion advocacy. The portrayal of abortion onscreen, in the news, and online through social media has a significant impact on cultural, personal, and political beliefs in the United States. This is an emerging field of research with wide spread potential impact across several arenas: medicine, policy, public health.

  6. Organizational Communication and Media

    DEFF Research Database (Denmark)

    Tække, Jesper

    of Niklas Luhmann (Tække & Paulsen 2008, Tække 2008a) with analysis of how organizations communicate in and about media. Using systems theory and form theory, it puts forward a theoretical framework and a strategy for analysing organisational communication in and about media. The medium aspect is inspired......  The paper reflects an interest in the relation between organizational communication and media. It tries to answer the question, how we can observe the relationship between organizational communication and media. It is a work-in-progress which tries to combine organizational studies inspired...... is a possible framework to draw the two disciplines together in, because it is a theory about the relation between the social and the media it is based on. First the paper sum up the Luhmann inspired theory about organizations, fleshing out how organizations are thought to communicate in and about media and how...

  7. Pervasive media violence.

    Science.gov (United States)

    Schooler, C; Flora, J A

    1996-01-01

    In this review, we focus our discussion on studies examining effects on children and young adults. We believe that the current epidemic of youth violence in the United States justifies a focus on this vulnerable segment of society. We consider media effects on individual children's behaviors, such as imitating aggressive acts. In addition, we examine how the media influence young people's perceptions of norms regarding interpersonal relationships. Next, we assess mass media effects on societal beliefs, or what children and adolescents think the "real world" is like. We suggest these media influences are cumulative and mutually reinforcing, and discuss the implications of repeated exposure to prominent and prevalent violent media messages. Finally, we catalog multiple intervention possibilities ranging from education to regulation. From a public health perspective, therefore, we evaluate the effects that pervasive media messages depicting violence have on young people and present multiple strategies to promote more healthful outcomes.

  8. New Media, New Citizens?

    DEFF Research Database (Denmark)

    Ohme, Jakob

    2017-01-01

    as for different age groups, the thesis shows that digital and especially social media use can be a strong driver of citizen participation. Besides looking at immediate mobilizing effects, the book sheds light on how digital media use may shape participation patterns through a long-term change in citizenship......The use of news media is regarded as a driver for citizens’ engagement with society and their political participation. But as news media use increasingly shifts to digital platforms, it is crucial to understand the interplay between a changing media environment and recent patterns of political...... participation. Against the background of citizens’ diverse possibilities for receiving political information and being politically active nowadays, the book focuses on the impact of digital media on political participation in Denmark. By examining this relationship in election- and non-election times as well...

  9. Genre in media production

    Directory of Open Access Journals (Sweden)

    Hanne Bruun

    2011-08-01

    Full Text Available How do we explain changes in media genres? Are they the result of economic, technological or other kinds of structural forces; or are they the result of the change-producing agency of the media producers? And how are changes in media texts connected to contextual conditions for media production on micro-, meso- or macro levels? This article suggests that a theoretical approach using a pragmatic and socio-cognitive understanding of genre will help us to address these questions. This approach can highlight the interplay between human agency and different kinds of structural forces involved in specific professional media production cultures. Furthermore, it has the potential to integrate media texts and especially the micro- and meso levels of production. Using lessons learned and findings from my recent production study of Danish television satire, the article will argue three major methodological as well as knowledge-producing advantages of a genre approach.

  10. Internal Social Media

    DEFF Research Database (Denmark)

    Madsen, Vibeke Thøis

    2018-01-01

    Internal social media is a web-based communication arena that provides all organizational members with a communication opportunity. The media has emerged in organizations since 2004, and is increasingly seen as a way of giving employees a voice in organizations which can benefit the organization...... in terms of knowledge sharing, collaboration, and employee participation and engagement. The first wave of studies of internal social media was primarily from an information-systems perspective and focused more on its adoption, its affordances, and the outcome of its introduction. The second wave...... of studies was more concerned with studying the dynamics of communication on internal social media, in order to understand coworkers as strategic communicators and how communication on internal social media can constitute the organization. With a successful introduction of internal social media, coworkers...

  11. The Media Mixer

    DEFF Research Database (Denmark)

    Vestergaard, Vitus; Mortensen, Christian Hviid

    works; works that are based on already existing works. This cultural practice thrives throughout the Internet, most notably on web2.0 sites like YouTube. The Media Museum has embraced the remix paradigm with the development of an interactive media experience centre called the Media Mixer. Here...... that the practice of remixing can be a potent means to achieve meaningful user participation in the digital museum age....

  12. Doing social media analytics

    OpenAIRE

    Brooker, P; Barnett, J; Cribbin, TF

    2016-01-01

    'The era of Big Data has begun' (boyd and Crawford, 2012: 662). In the few years since this statement, social media analytics has begun to accumulate studies drawing on social media as a resource and tool for research work. Yet, there has been relatively little attention paid to the development of methodologies for handling this kind of data. The few works that exist in this area often reflect upon the implications of 'grand' social science methodological concepts for new social media researc...

  13. Antennas in inhomogeneous media

    CERN Document Server

    Galejs, Janis; Fock, V A; Wait, J R

    2013-01-01

    Antennas in Inhomogeneous Media details the methods of analyzing antennas in such inhomogeneous media. The title covers the complex geometrical configurations along with its variational formulations. The coverage of the text includes various conditions the antennas are subjected to, such as antennas in the interface between two media; antennas in compressible isotropic plasma; and linear antennas in a magnetoionic medium. The selection also covers insulated loops in lossy media; slot antennas with a stratified dielectric or isotropic plasma layers; and cavity-backed slot antennas. The book wil

  14. Overview: new media.

    Science.gov (United States)

    O'Keeffe, Gwenn Schurgin

    2012-06-01

    Pediatricians care for children's growth and development from the time they are born until they become adults. In addition, pediatricians must be vigilant for external influences. Technology influences children of all ages. Seventy-five percent of teenagers own cell phones, with 25% using them for social media. Technology can lead to an increase in skills and social benefits but there is also the potential for harm such as sexting, cyberbullying, privacy issues, and Internet addiction, all of which can affect health. Pediatricians must become well versed in the new media to provide media-oriented anticipatory guidance and advice on media-related issues. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Media multitasking in adolescence.

    Science.gov (United States)

    Cain, Matthew S; Leonard, Julia A; Gabrieli, John D E; Finn, Amy S

    2016-12-01

    Media use has been on the rise in adolescents overall, and in particular, the amount of media multitasking-multiple media consumed simultaneously, such as having a text message conversation while watching TV-has been increasing. In adults, heavy media multitasking has been linked with poorer performance on a number of laboratory measures of cognition, but no relationship has yet been established between media-multitasking behavior and real-world outcomes. Examining individual differences across a group of adolescents, we found that more frequent media multitasking in daily life was associated with poorer performance on statewide standardized achievement tests of math and English in the classroom, poorer performance on behavioral measures of executive function (working memory capacity) in the laboratory, and traits of greater impulsivity and lesser growth mindset. Greater media multitasking had a relatively circumscribed set of associations, and was not related to behavioral measures of cognitive processing speed, implicit learning, or manual dexterity, or to traits of grit and conscientiousness. Thus, individual differences in adolescent media multitasking were related to specific differences in executive function and in performance on real-world academic achievement measures: More media multitasking was associated with poorer executive function ability, worse academic achievement, and a reduced growth mindset.

  16. The digital media handbook

    CERN Document Server

    Dewdney, Andrew

    2013-01-01

    The new edition of The Digital Media Handbook presents an essential guide to the historical and theoretical development of digital media, emphasising cultural continuity alongside technological change, and highlighting the emergence of new forms of communication in contemporary networked culture.Andrew Dewdney and Peter Ride present detailed critical commentary and descriptive historical accounts, as well as a series of interviews from a range of digital media practitioners, including producers, developers, curators and artists.The Digital Media Handbook highlights key concerns of today's prac

  17. The Media Mixer

    DEFF Research Database (Denmark)

    Vestergaard, Vitus; Mortensen, Christian Hviid

    2011-01-01

    We explore how remixing and content sharing can be used as a means for user participation in a digital museum age. Remix culture is seen as a culture that allows and encourages the production of derivative works; works that are based on already existing works. This cultural practice thrives...... throughout the Internet, most notably on web 2.0 sites like YouTube. The Media Museum has embraced the remix paradigm with the development of an interactive media experience centre called the Media Mixer. Here the museum users can produce, deconstruct, reconstruct and finally publish and share digital media...

  18. Self-media

    DEFF Research Database (Denmark)

    Fausing, Bent

    2015-01-01

    The self and identity are not only topics related to the selfies. They are connected to the development of media since the renaissance, the self-media. This is the thesis of the following. The subject, the self, is most clearly exposed in the face, and face and identity becomes important in the m......The self and identity are not only topics related to the selfies. They are connected to the development of media since the renaissance, the self-media. This is the thesis of the following. The subject, the self, is most clearly exposed in the face, and face and identity becomes important...

  19. Media Education and Native Peoples.

    Science.gov (United States)

    Greer, Sandy

    1991-01-01

    Media literacy encourages critical thinking about the news media, advertising, and popular culture. Media education of American Indian students challenges mass media's stereotyped aboriginal representations and the mainstream values of egotism and consumerism. Integrated across the curriculum at all grades, media education is empowering and…

  20. Japanese Media in English.

    Science.gov (United States)

    Tanaka, Sachiko Oda

    1995-01-01

    Describes the use of English in the media in Japan, focusing on the role and history of English-language newspapers, radio, and television programs, as well as the proliferation of English-language films shown in Japanese cinemas. Discusses the implications of English in the Japanese media. (20 references) (MDM)

  1. Trends in Media Use

    Science.gov (United States)

    Roberts, Donald F.; Foehr, Ulla G.

    2008-01-01

    American youth are awash in media. They have television sets in their bedrooms, personal computers in their family rooms, and digital music players and cell phones in their backpacks. They spend more time with media than any single activity other than sleeping, with the average American eight- to eighteen-year-old reporting more than six hours of…

  2. Media Education in France.

    Science.gov (United States)

    La Borderie, Rene

    1984-01-01

    Two mass media projects that are being integrated into the national French education system are described. The "Socio-Cultural Education" program is intended to help future farmers understand and cope with social situations involving communication. The "Introduction to Communication and the Media" project helps students deal…

  3. Media Entertainment and emotions

    DEFF Research Database (Denmark)

    Tan, Ed S.

    2017-01-01

    The chapter presents a psychological framework for entertainment experiences. It reviews types of emotion and their associations with media entertainment contents, explaining the role of genre.......The chapter presents a psychological framework for entertainment experiences. It reviews types of emotion and their associations with media entertainment contents, explaining the role of genre....

  4. Media and the Trustee.

    Science.gov (United States)

    Hamilton, Jan; Hartstein, Raymond

    1985-01-01

    Underscores the importance of community college trustees' working effectively with the news media. Discusses ways of protecting the institution's image, variables affecting image, public relations policies, the role of the board chair, marketing responsibilities, and trustee actions that can strain media relations. Offers guidelines for dealing…

  5. EMMSE Media Index.

    Science.gov (United States)

    Hewitt, Clifford A., Comp.; McKinstry, Herbert A., Comp.

    This index provides a topical taxonomy of media which have been selected for their relevance in the teaching of materials science and engineering. The index is keyed to a matrix which matches topical and/or class material with six classifications of media: print, 16mm film, super 8 film, slide/tape, videotape, and other (including interactive…

  6. Division Level Social Media

    Science.gov (United States)

    2015-06-12

    06-2015 2. REPORT TYPE Master’s Thesis 3. DATES COVERED (From - To) AUG 2014 – JUNE 2015 4. TITLE AND SUBTITLE Division Level Social Media...13. SUPPLEMENTARY NOTES 14. ABSTRACT Social media has become an accepted form of communication in society including the U.S. Army. Currently

  7. Mapping Media and Meaning

    DEFF Research Database (Denmark)

    Chamberlain, Alan; Bødker, Mads; Papangelis, Konstantinos

    2017-01-01

    places and intangible personal content can be used to develop meaningful experiences. The paper explores the use of autoethnography as a method for soundscape design in the fields of personal heritage and locative media. Specifically, we explore possible connections between digital media, space...

  8. Social Media. Research Brief

    Science.gov (United States)

    Williamson, Ronald

    2010-01-01

    The growing use of social media by students and adults is impacting schools. A recent Pew study found that 73% of teens use social-networking sites to connect with others. Social media includes blogs, wikis, and podcasts as well as sites such as MySpace, Facebook, and Linkedin. While such sites promote connection with others, their use has created…

  9. Mobile Media Photography

    DEFF Research Database (Denmark)

    Svabo, Connie; Shanks, Michael

    2013-01-01

    Mobile media photography marks a shift in orientation from the image towards photography as a mode of engagement. This leads is to explore the processes of experience and documentation that mobile media help to constitute. We unfold two aspects of the process of photography: photography as temporal...

  10. Understanding social media logic

    NARCIS (Netherlands)

    van Dijck, J.; Poell, T.

    2013-01-01

    Over the past decade, social media platforms have penetrated deeply into the mech­anics of everyday life, affecting people's informal interactions, as well as institutional structures and professional routines. Far from being neutral platforms for everyone, social media have changed the conditions

  11. Photonic layered media

    Science.gov (United States)

    Fleming, James G.; Lin, Shawn-Yu

    2002-01-01

    A new class of structured dielectric media which exhibit significant photonic bandstructure has been invented. The new structures, called photonic layered media, are easy to fabricate using existing layer-by-layer growth techniques, and offer the ability to significantly extend our practical ability to tailor the properties of such optical materials.

  12. Building Social Media Connections

    Science.gov (United States)

    Ferriter, William N.; Ramsden, Jason T.; Sheninger, Eric C.

    2012-01-01

    Incorporating social media tools into your professional practices does not have to be intimidating as long as you are willing to tackle five action steps. It is far easier to articulate the strengths--and to imagine the possibilities--of social media spaces as tools for communication and professional development when you are actively using those…

  13. Corporate Media Governance

    NARCIS (Netherlands)

    Kempen, Petrus Cornelis

    2011-01-01

    The media can make or break a reputation. This being said, it seems to be essential for companies, governments and institutions to pay specific attention to corporate media management in their daily operations. However, this thesis shows that they often neglect to pay adequate attention to corporate

  14. Trolling new media: violent extremist groups recruiting through social media

    OpenAIRE

    Chang, Mark D.

    2015-01-01

    Approved for public release; distribution is unlimited With the advent and subsequent growth of several new media technologies, violent extremist groups have incorporated social media into recruiting strategies. How are violent extremist groups using social media for recruiting? This thesis explores several new media technologies—websites, blogs, social media, mobile phones, and online gaming—to determine if violent extremist groups rely on social media for recruiting. By comparing the com...

  15. Media, Society, World: Social Theory and Digital Media Practice

    OpenAIRE

    Couldry, Nick

    2012-01-01

    Media are fundamental to our sense of living in a social world. Since the beginning of modernity, media have transformed the scale on which we act as social beings. And now in the era of digital media, media themselves are being transformed as platforms, content, and producers multiply. \\ud \\ud Yet the implications of social theory for understanding media and of media for rethinking social theory have been neglected; never before has it been more important to understand those implications. Th...

  16. Media Sociography on Weblogs

    DEFF Research Database (Denmark)

    Tække, Jesper

    to the media it is based on. Theoretically seen it is inspired of two theoretical paradigms the Sociological Systems Theory of Niklas Luhmann and the Media Theory (also called the Toronto school). Empirically the paper primary draws on the literature about weblogs, which could be framed as CMC......Weblogs are not only one of the newest technical media for communication, but also one of the most difficult to understand. Are weblogs a kind of mass medium, a personal medium like an online diary, or a medium that gives space for communities to grow? Or are weblogs a medium that enable all...... these possibilities depended on the actual use? This paper throws some light on what weblogs are by using the methodology of Media Sociography (Tække 2003, 2004a, 2004b and 2004c). Media Sociography is a strategy for analysing mediated social systems or in other words a strategy for describing the social in relation...

  17. Social Media Reputation

    DEFF Research Database (Denmark)

    Etter, Michael; Colleoni, Elanor; Ravasi, Davide

    directly to corporate performance and actions. Secondly, prominent reputation measurements couple stakeholders´ believes to reputation drivers through the use of predefined scales and items. We argue that with the rise of social media a company´s reputation has increasingly become autonomous from corporate...... actions, which demands a greater decoupling of stakeholders´ perceptions from corporate signals or actions in corporate reputation research. We develop the concept of social media reputation as the overall evaluation of a company presented in social media and present a new approach of measuring reputation...... based on social media data that accounts for the autonomy of stakeholder´s perception of a firm. We compare and contrast this novel social media reputation measure (SMRM) with traditional reputation measurements and find that SMRM is a valuable measurement to capture the autonomy of the stakeholders...

  18. Social Media Policies

    DEFF Research Database (Denmark)

    Stohl, Cynthia; Etter, Michael; Banghart, Scott

    2017-01-01

    Three global developments situate the context of this investigation: the increasing use of social media by organizations and their employees, the burgeoning presence of social media policies, and the heightened focus on corporate social responsibility (CSR). In this study the intersection...... of these trends is examined through a content analysis of 112 publicly available social media policies from the largest corporations in the world. The extent to which social media policies facilitate and/or constrain the communicative sensibilities and values associated with contemporary notions of CSR...... negotiation and participation in the social responsibilities of corporations. Moreover, policies generally enact organizational communication practices that are contrary to international CSR guidelines (e.g., the UN Global Compact and other international agreements). Findings suggest that social media...

  19. Populism and the media

    DEFF Research Database (Denmark)

    Esser, Frank; Stepinska, Agnieszka; Hopmann, David Nicolas

    2017-01-01

    European media systems have gone through major changes in the last few decades, and these changes have included increased opportunity structures for the dissemination of populist messages. Chapter 12 (‘Switzerland’) rightly states that the disappearance of the traditional party press, increased...... media ownership concentration, dependence on advertising, and a stronger orientation toward news values have worked in favor of a growing populist discourse. The newly established online media are seen as having a high afnity to populism’s rhetorical persuasion because both aim for the “quick kick....../click” with a broad audience. As was stated in Chapter 1 in this volume, the role that the media play in the dissemination of populism is largely under-explored. In the classical research literature dealing with populism (see, e.g., Canovan, 1981; Taggart, 2000), communication and media are not addressed at all. When...

  20. From media crossing to media mining

    NARCIS (Netherlands)

    de Jong, Franciska M.G.; Piperidis, S.; Cunningham, H.; Tablan, V.

    2006-01-01

    This paper reviews how the concept of Media Crossing has contributed to the advancement of the application domain of information access and explores directions for a future research agenda. These will include themes that could help to broaden the scope and to incorporate the concept of

  1. Media Roles and Legislators' New Media Use.

    Science.gov (United States)

    Riffe, Daniel

    1990-01-01

    Surveys 82 Alabama legislators and finds officials' views of the press as adversary or agent of consensus relates to perceived value of media for job-relevant information. Suggests a dysfunction of the "watch-dog" role because those believing the consensus model found the press more useful than those seeing the press as an adversary. (MG)

  2. Bullying and social media affordances

    OpenAIRE

    Brailas, Alexios

    2016-01-01

    What constitutes a good and sustainabledigital living?Social media literacyCan we talk about social media intelligence?Can we talk about digital intelligence?How bullying is complicated by special social media affordances?

  3. Social media modeling and computing

    CERN Document Server

    Hoi, Steven CH; Boll, Susanne; Xu, Dong; Jin, Rong; King, Irwin

    2011-01-01

    Presents contributions from an international selection of preeminent experts in the field Discusses topics on social-media content analysis, and examines social-media system design and analysis Describes emerging applications of social media

  4. Elements of Poro-Elasticity for Reservoir Engineering Éléments de poro-élasticité pour l'ingénierie de réservoirs

    Directory of Open Access Journals (Sweden)

    Bouteca M.

    2006-11-01

    Full Text Available Poro-elasticity is introduced by establishing the parallel between the equations of elastic solid mechanics and the equations describing the single-phase flow of a fluid in a porous medium. We then develop a number of practical applications of poro-elasticity for reservoir engineering. In conclusion, we demonstrate that poro-elasticity helps to define rigorously the total compressibility factor of the diffusivity equation, and we quantify the contribution of the elastic deformation of the rock to production. Dans la première partie de ce document nous élaborons progressivement les équations de la poro-élasticité. On établit tout d'abord le parallèle entre les équations de la mécanique du solide déformable et l'équation décrivant l'écoulement d'un fluide incompressible dans un milieu poreux. La démarche adoptée pour établir ces équations (définition d'un potentiel, de son gradient, du flux associé et de la divergence du flux sera conservée tout au long de la première partie. Le parallèle étant établi on montre les modifications apportées par la prise en compte de la compressibilité du fluide. La poro-élasticité n'est introduite qu'après cette étape, et l'on souligne les modifications introduites par le couplage entre l'écoulement du fluide et la déformation du milieu poreux. A ce stade, l'équation de diffusivité hydraulique contient un terme de couplage qui décrit la contribution de la déformation du solide à l'écoulement du fluide. L'ensemble de la démarche est illustré par trois tableaux synthétiques (tableaux 1 à 3. Les bases de la poro-mécaniques ont été définies par M. A. Biot dont les travaux demeurent la référence indispensable. Nous avons également eu recours aux travaux de 0. Coussy, en particulier nous avons utilisé la masse fluide comme variable au lieu d'utiliser le volume fluide. Dans la deuxième partie de ce document, nous montrons quelques applications de la poro

  5. Social Media Marketing in Russia

    OpenAIRE

    Olgskaya, Kristina

    2017-01-01

    Social media marketing involves the use of social media for connecting with prospective consumers. The study focuses on explaining such notions like social media marketing (SMM), types of SMM, differences between social media and traditional marketing, social media marketing plan, development ways of strategic social media marketing plan and why strategy may fail. This thesis also presents research in Russian social network – Vkontakte, where promotion of Mechanical Engineering programme ...

  6. CLASSICAL MEDIA RELATIONS AND NEW MEDIA RELATIONS IN SPORT

    Directory of Open Access Journals (Sweden)

    Alexandru Lucian MIHAI

    2014-06-01

    Full Text Available Media relations in sport mean maintenance of networks and positive relationships with people in the media to obtain positive media exposure for a sport product (informal and formal information sessions with media representatives. Because of the pervasive influence the media has on marketing success, sport marketers must make concerted efforts to create a positive relationship between their sport event and the media. They may accomplish this by providing the media with press releases, having news conferences, having media-day events (in which the media are invited to interact with the players, coaches, and administrators, providing media guides for the respective sport events and so on. Each of these activities promotes active involvement from the media, which will subsequently contribute to relationship building with the community.

  7. Media multitasking and implicit learning.

    Science.gov (United States)

    Edwards, Kathleen S; Shin, Myoungju

    2017-07-01

    Media multitasking refers to the simultaneous use of different forms of media. Previous research comparing heavy media multitaskers and light media multitaskers suggests that heavy media multitaskers have a broader scope of attention. The present study explored whether these differences in attentional scope would lead to a greater degree of implicit learning for heavy media multitaskers. The study also examined whether media multitasking behaviour is associated with differences in visual working memory, and whether visual working memory differentially affects the ability to process contextual information. In addition to comparing extreme groups (heavy and light media multitaskers) the study included analysis of people who media multitask in moderation (intermediate media multitaskers). Ninety-four participants were divided into groups based on responses to the media use questionnaire, and completed the contextual cueing and n-back tasks. Results indicated that the speed at which implicit learning occurred was slower in heavy media multitaskers relative to both light and intermediate media multitaskers. There was no relationship between working memory performance and media multitasking group, and no relationship between working memory and implicit learning. There was also no evidence for superior performance of intermediate media multitaskers. A deficit in implicit learning observed in heavy media multitaskers is consistent with previous literature, which suggests that heavy media multitaskers perform more poorly than light media multitaskers in attentional tasks due to their wider attentional scope.

  8. Media Literacy in Montenegro

    Directory of Open Access Journals (Sweden)

    Jelena Perovic

    2015-12-01

    Full Text Available Few countries in the world have introduced media education into their curriculums. Montenegro became one of them in 2009, when “media literacy” was introduced as an optional subject for 16 and 17 year old students of Gymnasium high schools. This article presents the findings of the first and only research conducted so far on media education in Montenegro. It is a national case study which examines the potential of media education to change the school culture and accelerate education system reform towards embracing the new digital education paradigm in the future. The focus is on the results of research conducted through in-depth interviews with media literacy teachers all over the country. Despite the many challenges, all teachers identify the potential of media education to strengthen some of the key competences of the students and to improve their motivation and academic performance. They also identify potential to change positively school culture by transforming teachers into “cultural mediators” (Morcellini, 2007 and by supporting the formation of a “participative culture” (Jenkins & Kelley, 2013 in schools. This research recommends focusing education reform on spreading the media education pedagogy to the entire curriculum in order to embrace the new digital education paradigm in the future.

  9. Social Media and Bullshit

    Directory of Open Access Journals (Sweden)

    Rasmus Kleis Nielsen

    2015-04-01

    Full Text Available To understand the role of social media in society, we have to understand how social media are understood. We need to analyze how different actors and organizations see and think about technology, the forms of knowledge that people draw on as they make sense of, develop, and use social media. Central among these is bullshit. This short essay discusses bullshit as defined by the philosopher Harry Frankfurt as statements made with little or no concern for their truth-value or justification and argues that social media are accompanied by unusually large amounts of bullshit for two reasons. First, they confront us with epistemological problems and are hard to understand. Second, there is a large demand for knowledge about what they mean, a powerful political economy that generates a lot of statements about social media, including substantial amounts of bullshit. Given the rapid development of social media and their growing importance, this is unlikely to change in the near future. Bullshit is here to stay, and we need to take it seriously intellectually and analytically to understand social media.

  10. Media Challenging Status Quo

    DEFF Research Database (Denmark)

    Sandvik, Kjetil

    ). Skeptical internet sociologists such as Morozov (2011) point out that the same media which was used e.g. to mobilize the ‘Twitter revolution’ in Iran in 2009 also was used by the regime to infiltrate and strike down the democratic movement. Following such position statements, international media...... and communication research is currently engaging in a longer and deeper process of examining and assessing the cultural consequences of networked communication. One present challenge is to understand digital media and networked communication at the intersection of established and countercultural, utopian...

  11. Media challenging capitalism

    DEFF Research Database (Denmark)

    Sandvik, Kjetil

    ). Skeptical internet sociologists such as Morozov (2011) point out that the same media which was used e.g. to mobilize the ‘Twitter revolution’ in Iran in 2009 also was used by the regime to infiltrate and strike down the democratic movement. Following such position statements, international media...... and communication research is currently engaging in a longer and deeper process of examining and assessing the cultural consequences of networked communication. One present challenge is to understand digital media and networked communication at the intersection of established and countercultural, utopian...

  12. Media violence and youth.

    Science.gov (United States)

    Beresin, E V

    1999-06-01

    This column reviews the literature on violence in the media and its effects on youth. The author summarizes the findings of naturalistic, longitudinal, and population-based studies conducted over the last 30 years. The literature provides compelling evidence that exposure of media violence to children plays a major role in the etiology of aggressive behavior. Psychiatrists can facilitate primary prevention of violence in our society by discussing the problem of media violence with parents, medical students, residents, and allied health and school professionals.

  13. Open Media Science

    DEFF Research Database (Denmark)

    Møller Moltke Martiny, Kristian; Pedersen, David Budtz; Hansted, Allan Alfred Birkegaard

    2016-01-01

    In this article, we present three challenges to the emerging Open Science (OS) movement: the challenge of communication, collaboration and cultivation of scientific research. We argue that to address these challenges OS needs to include other forms of data than what can be captured in a text...... and extend into a fully-fledged Open Media movement engaging with new media and non-traditional formats of science communication. We discuss two cases where experiments with open media have driven new collaborations between scientists and documentarists. We use the cases to illustrate different advantages...

  14. Media for Reflection

    DEFF Research Database (Denmark)

    Knudsen, Morten

    2016-01-01

    This article develops the concept media for reflection in the interest of conceptualizing the interpretative frames that enable and limit reflection in management and leadership education. The concept ‘media for reflection’ allows us to conceptualize the social and cultural mediation of reflection...... of the mediations is analysed as well as the societal and organizational background. Furthermore, the means by which the two media enable and limit reflection in different ways is compared. Finally, the article discusses possible implications of the analysis in terms of management and leadership education....

  15. Cross-Fertilization of Indigenous Media and New Media for ...

    African Journals Online (AJOL)

    This work cross examined the chance, consequences and challenges of crossfertilizing indigenous media with new media for the purpose of practicing development journalism in Africa with reference to the Nigeria society. The call to cross-fertilize indigenous media and new media has been on the front burner since 1980's ...

  16. From hybrid-media system to hybrid-media politicians

    DEFF Research Database (Denmark)

    Ørsten, Mark; Eberholst, Mads Kæmsgaard; Burkal, Rasmus

    2017-01-01

    An increasingly complex hybrid system of social- and traditional-news media surrounds Nordic election campaigns as politically experienced incumbents favour traditional news media, and younger, lesser-known candidates’ social media. Despite little evidence for hybrid-media politicians, politicians...

  17. Stochastic porous media equations

    CERN Document Server

    Barbu, Viorel; Röckner, Michael

    2016-01-01

    Focusing on stochastic porous media equations, this book places an emphasis on existence theorems, asymptotic behavior and ergodic properties of the associated transition semigroup. Stochastic perturbations of the porous media equation have reviously been considered by physicists, but rigorous mathematical existence results have only recently been found. The porous media equation models a number of different physical phenomena, including the flow of an ideal gas and the diffusion of a compressible fluid through porous media, and also thermal propagation in plasma and plasma radiation. Another important application is to a model of the standard self-organized criticality process, called the "sand-pile model" or the "Bak-Tang-Wiesenfeld model". The book will be of interest to PhD students and researchers in mathematics, physics and biology.

  18. Fractured porous media

    CERN Document Server

    Adler, Pierre M; Mourzenko, Valeri V

    2013-01-01

    This monograph on fractures, fracture networks, and fractured porous media provides a systematic treatment of their geometrical and transport properties for students and professionals in geophysics, materials science, and Earth sciences.

  19. Consolidating Social Media Strategies

    DEFF Research Database (Denmark)

    Gyimóthy, Szilvia; Munar, Ana Maria; Larson, Mia

    2014-01-01

    Gyimóthy & Larson (2014) portrayed three digital value co-creation strategies deployed by festival social media. Both frameworks provided novel analytical typologies which identified a series of categories (mimetic, analytic, immersion, advertising and insourcing, crowdsourcing and community consolidation......This study revisits and integrates the insights of recent studies on emergent social media strategies deployed by destination and event management organisations. In a comparative analysis Munar (2012) identified four generic approaches pursued by national tourism boards in the Nordic region, while......). This paper discusses the complementary nature of these conceptual proposals and advances an integrated conceptual framework of social media strategies. Based on the empirical findings of a case study that revisits evolving digital and social media strategies of European DMOs this paper maps the dynamics...

  20. Media and ICT

    DEFF Research Database (Denmark)

    Media and information and communication technologies (ICTs) have in the past decades been placed firmly on the educational agenda, and will continue to maintain this position, not least as catalysts for educational change. This issue is reflected in the anthology as it aims to respond to the ques......Media and information and communication technologies (ICTs) have in the past decades been placed firmly on the educational agenda, and will continue to maintain this position, not least as catalysts for educational change. This issue is reflected in the anthology as it aims to respond...... to the question of how the presence of media and ICT in and outside schools both change and qualify educational practice as well as how the cooperation between media, cultures, aesthetics and social relations affect and support new demands on education. The book represents different academic perspectives...

  1. TECHNETIUM SORPTION MEDIA REVIEW

    Energy Technology Data Exchange (ETDEWEB)

    DUNCAN JB; KELLY SE; ROBBINS RA; ADAMS RD; THORSON MA; HAASS CC

    2011-08-25

    This report presents information and references to aid in the selection of 99Tc sorption media for feasibility studies regarding the removal of 99Tc from Hanford's low activity waste. The report contains literature search material for sorption media (including ion exchange media) for the most tested media to date, including SuperLig 639, Reillex HPQ, TAM (Kruion), Purolite A520E and A530E, and Dowex 1X8. The U.S. Department of Energy (DOE), Office of River Protection (ORP) is responsible for management and completion of the River Protection Project (RPP) mission, which comprises both the Hanford Site tank farms and the Waste Treatment and Immobilization Plant (WTP). The RPP mission is to store, retrieve and treat Hanford's tank waste; store and dispose of treated wastes; and close the tank farm waste management areas and treatment facilities in a safe, environmentally compliant, cost-effective and energy-effective manner.

  2. New Media as Software

    Directory of Open Access Journals (Sweden)

    Manuel Portela

    2014-03-01

    Full Text Available Review of Lev Manovich, Software Takes Command: Extending the Language of New Media. London: Bloomsbury, 2013, 358 pp. ISBN 978-1-6235-6817-7. In Lev Manovich’s most recent book, this programmatic interrogation of our medial condition leads to the following question: do media still exist after software? This is the question that triggers Manovich’s dialogue both with computing history and with theories of digital media of recent decades, including the extension of his own previous formulations in The Language of New Media, published in 2001, and which became a major reference work in the field. The subtitle of the new book points precisely to this critical revisiting of his earlier work in the context of ubiquitous computing and accelerated transcoding of social, cultural and artistic practices by software.

  3. Balancing media environments

    DEFF Research Database (Denmark)

    Olesen, Mogens

    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...... interrelation between media technologies and users and specifying how our tools and media presents us with possibilities and limitations for action. For instance, a computer affords interaction with information in contrast to e.g. a book which affords information reception. Importantly, the affordance concept...... are perceived and pursued. Consequently, we can distinguish between perceived and hidden affordances (Norman 1999), as well as affordances that are desirable and undesirable in certain contexts. Thus, this paper promotes the affordance theory as a tool for analyzing which didactic potentials and problems...

  4. Media studies for scientists

    CERN Multimedia

    2002-01-01

    "Science, with its inherent uncertainties, can be hard to put across to the public. But blaming 'sloppy' journalism is too easy. If researchers are to make their points effectively, they should learn more about how the media work" (1 page).

  5. Streaming media bible

    National Research Council Canada - National Science Library

    Mack, Steve

    2002-01-01

    This book "tells you everything you need to know to produce professional-quality streaming media for the Internet, from an overview of the available systems and tools to high-end techniques for top quality results...

  6. Media Education, quo vadis?

    National Research Council Canada - National Science Library

    Petra Missomelius

    2015-01-01

    ... up. Hence the key questions are the goals of education, the required patterns of reflection and social configurations for generating knowledge, and the conditions of the digitally informed media culture...

  7. Spotlight on the media

    CERN Multimedia

    2007-01-01

    Do you want to know more about how the media works, how to deal with journalists? How to maximise opportunity and minimise threat? Then please join us on 22 November. This session will cover how to work effectively with the media, including print, radio and TV. You’ll get an insight into how journalists and news rooms operate. You’ll learn to recognise both soft balls and traps - and develop the techniques for dealing with them. The challenges of explaining CERN to any media outlet will be dealt with too. This interactive presentation, given by Jessica Pryce-Jones, Managing Director of the consultancy firm iOpener Ltd, and Nisha Pillai, news anchor for BBC World, will be illustrated with various case studies. How to deal with the media: maximising opportunity and minimising threat Thursday 22 November, from 4.30 pm, Main Auditorium, Bldg. 500 Coffee break before the event at 4.00 pm

  8. Understanding social media logic

    National Research Council Canada - National Science Library

    van Dijck, J; Poell, T

    2013-01-01

    Over the past decade, social media platforms have penetrated deeply into the mech­anics of everyday life, affecting people's informal interactions, as well as institutional structures and professional routines...

  9. Media and Security Team

    Data.gov (United States)

    Federal Laboratory Consortium — The Media And Security Team led by Prof. Min Wu was established in Fall 2001 at University of Maryland, College Park. A number of research and education activities...

  10. Media multitasking in adolescence

    National Research Council Canada - National Science Library

    Cain, Matthew S; Leonard, Julia A; Gabrieli, John D. E; Finn, Amy S

    2016-01-01

    ... behavior and real-world outcomes. Examining individual differences across a group of adolescents, we found that more frequent media multitasking in daily life was associated with poorer performance on statewide standardized...

  11. Emotion in Social Media

    OpenAIRE

    Panger, Galen Thomas

    2017-01-01

    The role of emotion in social media has been the subject of considerable research and media attention. But while stereotypes about the emotional profile of status updates — that they are overly-positive, or overly-angry — have solidified, evidence remains circumstantial and indirect. Further, although researchers have made numerous efforts to use the emotions we express in status updates to make inferences about our emotional lives — generating national happiness indices, predicting mental il...

  12. On commercial media bias

    OpenAIRE

    Germano, Fabrizio

    2008-01-01

    Within the spokes model of Chen and Riordan (2007) that allows for non-localized competition among arbitrary numbers of media outlets, we quantify the effect of concentration of ownership on quality and bias of media content. A main result shows that too few commercial outlets, or better, too few separate owners of commercial outlets can lead to substantial bias in equilibrium. Increasing the number of outlets (commercial and non-commercial) tends to bring down this bias; but the strongest ef...

  13. Communications and media services

    Science.gov (United States)

    Mcculla, James W.; Kukowski, James F.

    1990-01-01

    NASA's internal and external communication methods are reviewed. NASA information services for the media, for the public, and for employees are discussed. Consideration is given to electron information distribution, the NASA TV-audio system, the NASA broadcast news service, astronaut appearances, technology and information exhibits, speaker services, and NASA news reports for internal communications. Also, the NASA worldwide electronic mail network is described and trends for future NASA communications and media services are outlined.

  14. Social Media Cocreation Strategies

    DEFF Research Database (Denmark)

    Gyimóthy, Szilvia; Larson, Mia

    2015-01-01

    This paper explores how social media becomes a part of integrated marketing communications of festival organizations. The purpose of this paper is to conceptualize the co-creation of festival experiences online by comparing managerial strategies and communicative patterns of three large....... Based on the empirical findings, we propose an analytical framework to improve our understanding of the management of social media communications, offering three distinct value co-creation strategies in a festival context....

  15. Drupal 7 media

    CERN Document Server

    Tal, Liran

    2013-01-01

    This is a practical, hands-on guide packed with examples that will help you build rich Drupal 7 media web applications.If you are a Drupal site builder and you wish to spice up your web applications with rich media content, then this book is for you. A basic understanding of HTML, JavaScript, and basic PHP module development in Drupal would be helpful, but is not necessary.

  16. Digital Media Ethics

    DEFF Research Database (Denmark)

    Ess, Charles

    Provides a philosophical-ethical "toolkit" for analyzing central ethical issues evoked by our use of new media, including privacy, copyright, violent and sexual content online, and cross-cultural communication online.......Provides a philosophical-ethical "toolkit" for analyzing central ethical issues evoked by our use of new media, including privacy, copyright, violent and sexual content online, and cross-cultural communication online....

  17. Media and Multiplicity

    DEFF Research Database (Denmark)

    Blaagaard, Bolette

    2010-01-01

    In the past few years continental Europe has experienced a resurgence of right-wing party politics, nationalism and xenophobia. In this nationalist revival the media and advanced communications technologies have played a significant role, as evidenced by the debates following cases such as the Da...... explores the tensions within the relation between journalistic practice and the construction of the idea of the nation and the multiplicity of media and cultures which inhabit the spheres of journalism and nation....

  18. Media Accountability Goes Online

    OpenAIRE

    Baisnée, Olivier; Domingo, David; Glowacki, Michal; Heikkilä, Heikki; Kus, Michal; Pies, Judith

    2012-01-01

    The Internet is both a challenge and an opportunity for media accountability. Newsrooms and citizens are adapting existing practices and developing new ones on news websites, weblogs and social media. This report offers the first comparative study on how these practices are being developed and perceived in thirteen countries in Europe (Bulgaria, Finland, France, Germany, the Netherlands, Poland, Serbia, United Kingdom), the Arab world (Jordan, Lebanon, Syria, Tunisia) and North America (USA)....

  19. The social media image

    Directory of Open Access Journals (Sweden)

    Nadav Hochman

    2014-08-01

    Full Text Available How do the organization and presentation of large-scale social media images recondition the process by which visual knowledge, value, and meaning are made in contemporary conditions? Analyzing fundamental elements in the changing syntax of existing visual software ontology—the ways current social media platforms and aggregators organize and categorize social media images—this article relates how visual materials created within social media platforms manifest distinct modes of knowledge production and acquisition. First, I analyze the structure of social media images within data streams as opposed to previous information organization in a structured database. While the database has no pre-defined notions of time and thus challenges traditional linear forms, the data stream re-emphasizes the linearity of a particular data sequence and activates a set of new relations to contemporary temporalities. Next, I show how these visual arrangements and temporal principles are manifested and discussed in three artworks: “Untitled” (Perfect Lovers by Felix Gonzalez-Torres (1991, The Clock by Christian Marclay (2011, and Last Clock by Jussi Ängeslevä and Ross Cooper (2002. By emphasizing the technical and poetic ways in which social media situate the present as a “thick” historical unit that embodies multiple and synchronous temporalities, this article illuminates some of the conditions, challenges, and tensions between former visual structures and current ones, and unfolds the cultural significations of contemporary big visual data.

  20. Media, risk and science

    CERN Document Server

    Allan, Stuart

    2002-01-01

    How is science represented by the media? Who defines what counts as a risk, threat or hazard, and why? In what ways do media images of science shape public perceptions? What can cultural and media studies tell us about current scientific controversies? "Media, Risk and Science" is an exciting exploration into an array of important issues, providing a much needed framework for understanding key debates on how the media represent science and risk. In a highly effective way, Stuart Allan weaves together insights from multiple strands of research across diverse disciplines. Among the themes he examines are: the role of science in science fiction, such as "Star Trek"; the problem of 'pseudo-science' in "The X-Files"; and how science is displayed in science museums. Science journalism receives particular attention, with the processes by which science is made 'newsworthy' unravelled for careful scrutiny. The book also includes individual chapters devoted to how the media portray environmental risks, HIV-AIDS, food s...

  1. Media Literacy and Active Citizenship

    OpenAIRE

    Karmen Erjavec

    1999-01-01

    This article answers the question What are the values, skills and knowledge that a citizen needs in a media-saturated society? Education about the media provides the answer: A media-literate citizen has access to the media; He knows how to analyse, critically evaluate and formulate various forms of communication and can also actively participate in the social life.

  2. Advertising media selection and planning

    NARCIS (Netherlands)

    Moorman, M.; Neijens, P.C.; Smit, E.G.; Belch, M.A.; Belch, G.E.

    2010-01-01

    Reach, frequency, and timing are key concepts in selecting TV, radio, newspapers, magazines, out-of-home, direct mail, Internet, and other media for advertising campaigns. We discuss these concepts and their role in media selection and media planning processes. We also describe media and audience

  3. Curricula for Media Education in Anglophone Africa.

    Science.gov (United States)

    Okigbo, Charles; Pratt, Cornelius B.

    1997-01-01

    Provides a basis for reconstructing media curricula by integrating normative media theory within Africa's media education and media training programs. Profiles media education programs in Kenya. Proposes a model curriculum for Kenya and for anglophone Africa. (RS)

  4. Mediatization Theory and Digital Media

    DEFF Research Database (Denmark)

    Finnemann, Niels Ole

    2011-01-01

    In the 20th century, the term "media logic" was introduced to denote the influence of independent mass media on political systems and other institutions. In recent years the idea has been reworked and labelled "mediatization" to widen the framework by including new media and new areas of applicat......In the 20th century, the term "media logic" was introduced to denote the influence of independent mass media on political systems and other institutions. In recent years the idea has been reworked and labelled "mediatization" to widen the framework by including new media and new areas...... trajectories and because in the new matrix the previously existing media have had to transform themselves....

  5. Children's media policy.

    Science.gov (United States)

    Jordan, Amy B

    2008-01-01

    Amy Jordan addresses the need to balance the media industry's potentially important contributions to the healthy development of America's children against the consequences of excessive and age-inappropriate media exposure. Much of the philosophical tension regarding how much say the government should have about media content and delivery stems from the U.S. Constitution's First Amendment protection against government interference in free speech, including commercial speech. Courts, Jordan says, have repeatedly had to weigh the rights of commercial entities to say what they please against the need to protect vulnerable citizens such as children. This balancing act is complicated even further, she says, because many government regulations apply only to broadcast television and not to non-broadcast media such as the Internet or cable television, though Congress has addressed the need to protect children's privacy online. The need to protect both free speech and children has given rise to a fluid media policy mix of federal mandates and industry self-regulation. Jordan describes the role of the three branches of the federal government in formulating and implementing media policy. She also notes the jockeying for influence in policymaking by industry lobbies, child advocacy groups, and academic researchers. The media industry itself, says Jordan, is spurred to self-regulation when public disapproval grows severe enough to raise the possibility of new government action. Jordan surveys a range of government and industry actions, from legislatively required parental monitoring tools, such as the V-Chip blocking device on television sets, to the voluntary industry ratings systems governing television, movies, and video games, to voluntary social website disclosures to outright government bans, such as indecency and child privacy information collection. She considers the success of these efforts in limiting children's exposure to damaging content and in improving parents

  6. Media coverage of women victimization

    OpenAIRE

    Konstantinović-Vilić, Slobodanka; Žunić, Natalija

    2012-01-01

    Mass media seem to be playing the central role in our everyday life and the media impact is so overpowering nowadays that we live in a mediasaturated culture. Not only are mass media an inseparable part of our contemporary life but they also significantly define and shape our daily existence. In order to explain the cultural impact that the media coverage of crime and victimization has in our society, it is necessary to understand the relationship between crime, victimization and mass media. ...

  7. Doing social media analytics

    Directory of Open Access Journals (Sweden)

    Phillip Brooker

    2016-07-01

    Full Text Available In the few years since the advent of ‘Big Data’ research, social media analytics has begun to accumulate studies drawing on social media as a resource and tool for research work. Yet, there has been relatively little attention paid to the development of methodologies for handling this kind of data. The few works that exist in this area often reflect upon the implications of ‘grand’ social science methodological concepts for new social media research (i.e. they focus on general issues such as sampling, data validity, ethics, etc.. By contrast, we advance an abductively oriented methodological suite designed to explore the construction of phenomena played out through social media. To do this, we use a software tool – Chorus – to illustrate a visual analytic approach to data. Informed by visual analytic principles, we posit a two-by-two methodological model of social media analytics, combining two data collection strategies with two analytic modes. We go on to demonstrate each of these four approaches ‘in action’, to help clarify how and why they might be used to address various research questions.

  8. Contemplative Media Studies

    Directory of Open Access Journals (Sweden)

    Kevin Healey

    2015-08-01

    Full Text Available The psychological and socio-economic implications of digital technologies call for scholarship that engages questions about the nature of human consciousness, the construction of the self and the ethics of technical development. In this article, I outline a framework for an approach called contemplative media studies. This approach incorporates several different scholarly threads, namely: via critical political-economic media scholarship, a focus on achieving social and economic justice through policy initiatives and structural reform; via media and religious scholarship, an interest in the religious dimensions of digital culture and the role of media in shaping religious identity; and via contemplative studies, an appreciation of the applicability of contemplative principles to research methods and theory. This framework allows us to examine the spiritual ideology that drives the construction of commercial digital platforms and to ask whether alternative platforms might better catalyze human development. Anchored in a critical commitment to socio-economic justice, contemplative media studies is aimed at articulating an ethically-responsive and economically-sustainable architecture of human flourishing.

  9. Media and Sexuality

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Carvalho

    2010-03-01

    Full Text Available One of the distinctive marks of current capitalism is the presence of mass media constituting the psyche in different aspects. Today, we observe the multiplication of many contents with erotic appeal in the media and the effects of this process are still to be known, particularly in the matter of sexuality. Concretely, what we have is that the practices and the effective conceptions of sexuality are suffering an accelerated transformation that involves the abandonment of the traditional practices. In this context, we can ask about the sense that is attributed to sexuality experiences and evaluate the impact of the different "manners of being" which are referred to sexuality and systematically diffused by the media. Therefore, we can explore the implications of this new scenery for different social realities: the family institution, the affectionate and loving relationships, the school and professional everyday life, as well as the formulation of public politics in this field.

  10. Media and metamedia management

    CERN Document Server

    Araújo, Xosé; Fernández, Valentín; García, Xosé

    2017-01-01

    Media and Metamedia Management has contributions from seven prestigious experts, who offer their expertise and the view from their vantage point on communication, journalism, advertising, audiovisual, and corporate, political, and digital communication, paying special attention to the role of new technologies, the Internet and social networks, also from an ethics and legal dimension. A total of 118 authors belonging to 31 universities from Spain, Portugal, England and Ecuador have contributed to this book edited, coordinated and introduced by professors Francisco Campos-Freire and Xosé López-García, from the University of Santiago de Compostela, José Rúas-Araújo, from the University of Vigo, and Valentín A. Martínez-Fernández, from the University of A Coruña. Readers may also enjoy 66 articles, grouped into diverse chapters, on Journalism and cyberjournalism, audiovisual sector and media economy, corporate and institutional communication, and new media and metamedia.

  11. Modern Media Phenomenon

    Directory of Open Access Journals (Sweden)

    Erika Prijatelj

    2011-09-01

    Full Text Available Contemporary media culture is de fi ned by the logic of the victorious spectacle expanding to all areas of life. Post-modern capitalism has turned everyday life and culture into entertainment with the help of the spectacular. In fact, such entertainment results in a fake sense of happiness, pop mainstream, the swallowing up alternatives and therefore the creation of a passive consumer society. The media today have a unique power of overwhelming a person with information. They enable a modern person to know much, but understand little. This discussion has cast some light on very popular reality shows, the body and sports. It concludes with a re fl ection on modern media, which leave a person of this age with a patchwork identity.

  12. 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 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...... in the educational interaction. In this way there is a huge gap between the claimed learning potential and the negative effects that currently appears. This schism can be found in many educational institutions, but in this paper we will focus on Danish upper secondary schools, where we have done empirical research...

  13. Open Media Training Session

    CERN Multimedia

    CERN. Geneva; Marchant, Nadia

    2010-01-01

    Have you ever wondered how the media work and why some topics make it into the news and other don't? Would you like to know how to (and how not to) give an interview to a journalist? With the LHC preparing for first collisions at high energies, the world's media are again turning their attention to CERN. We're all likely to be called upon to explain what is happening at CERN to media, friends and neighbours. The seminar will be given by BBC television news journalists Liz Pike and Nadia Marchant, and will deal with the kind of questions we're likely to be confronted with through the restart period. Follow the webcast: http://webcast.cern.ch/

  14. Enterprise Social Media

    DEFF Research Database (Denmark)

    Khajeheian, Datis

    2018-01-01

    This article reports an ethnographic research on effect of enterprise social media on communication of members in entrepreneurial teams. The researcher acted as an entrepreneur and as a team member in two entrepreneurial projects to observe the communication of team members within the enterprise...... social media. In addition to observation, he conducted some interviews with team members to collect supplementary data. A theoretical framework developed from an array of three metaphors: leaky pipe, echo chamber and social lubricant, and four organizational learning processes: social capital, boundary...... work, attention allocation and social analytics. By the interpretation of the collected data, a new metaphor of “living room” was proposed. This metaphor suggests that enterprise social media provide a space for interaction of internal-external people similar to what home members and guests do...

  15. Internet and Cross Media Productions

    DEFF Research Database (Denmark)

    Petersen, Anja Bechmann

    2006-01-01

    , the Internet continues to play a minor role when compared to older media. The content of the cross media concepts and organizations' history are crucial elements in deciding the priority and use of platforms. Methodologically, the article approaches cross media and the roles of the Internet on a micro......Convergence is one of the hot topics in Internet studies. Recently, however, media organizations have turned their focus to cross media communication. Media organizations are interested in optimizing communication across platforms such as TV, radio, websites, mobile telephones and newspapers....... The aim of this article is to examine the roles of the Internet when emphasis is put on cross media rather than convergence. This article proposes not one unidirectional convergent tendency but manifold roles of the Internet in cross media communication. Inside the media organizations, however...

  16. Children, Adolescents, and the Media.

    Science.gov (United States)

    2013-11-01

    Media, from television to the "new media" (including cell phones, iPads, and social media), are a dominant force in children's lives. Although television is still the predominant medium for children and adolescents, new technologies are increasingly popular. The American Academy of Pediatrics continues to be concerned by evidence about the potential harmful effects of media messages and images; however, important positive and prosocial effects of media use should also be recognized. Pediatricians are encouraged to take a media history and ask 2 media questions at every well-child visit: How much recreational screen time does your child or teenager consume daily? Is there a television set or Internet-connected device in the child's bedroom? Parents are encouraged to establish a family home use plan for all media. Media influences on children and teenagers should be recognized by schools, policymakers, product advertisers, and entertainment producers. Copyright © 2013 by the American Academy of Pediatrics.

  17. Death in media

    Directory of Open Access Journals (Sweden)

    Pavićević Aleksandra

    2010-01-01

    Full Text Available This paper discusses the role of media in a construction of public image speech and presentation of death. The main research questions could be posed as follows: does the media discourse confirm a thesis about modern society as the one which intensely avoids encounter with Death, or does it defy it? Frequent images or hints of death in visual media in films informative and entertainment programs-suggest certain changes related to this issue in the past few decades. This analysis focuses on printed media hence the paper assesses numerous issues of the daily journal Politika from 1963, 1972, 1973, 1979, 1985, 1991, 1995, 1999, 2007 and 2008, as well as some other daily journals after 2000. The analysis confirms a strong connection between the current political systems and ideology and speech about death. In addition, it reveals a political usage of this event but also speaks up about cultural and historical models, underlying all other constructions. During the 1960's and 1970's, the presentations, including the speech about death relied on the traditional understandings about inevitability of death and dying, and alternatively on atheistic beliefs related to the progress and wellbeing of the society. In this particular discourse, death was present to a limited degree, serving primarily to glorify socialist order. The end of the 1970's witnessed an increase in the glorification of the death, correlated with the decrease of the dominant political ideology. On the other hand, the 1990's brought about more presence of the national and religious symbolism and glorification of the dead as heroes. After 2000, mercantilism is evident throughout the media. All of the media broadcast drastic images of death and dead, thus providing an answer to the posed question at the beginning of this paper about the relationship of the modern society towards death but nevertheless, this still leaves out many implicit consequences and possible meanings.

  18. Creative Digital Media Practices

    DEFF Research Database (Denmark)

    Frølunde, Lisbeth

    on collaboration (Benkler, 2006). The shift toward visual modes and digital media practices pose many pedagogical challenges for academics. I want to raise questions on how to teach “dialogically” with and through creative, digital media practices based on my plans for a course in Fall, 2011, where students...... and personal levels. The discussion includes pedagogical issues in regards to the upcoming university course, such as: how to encourage dialogic reflection between students as authors and viewers of digital stories, and how to support their application and integration of visual and dialogic communication...

  19. Acute otitis media.

    Science.gov (United States)

    Dickson, Gretchen

    2014-03-01

    One in 4 children will have at least 1 episode of acute otitis media (AOM) by age 10 years. AOM results from infection of fluid that has become trapped in the middle ear. The bacteria that most often cause AOM are Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Differentiating AOM from otitis media with effusion (OME) is a critical skill for physicians, as accurate diagnosis will guide appropriate treatment of these conditions. Although fluid is present in the middle ear in both conditions, the fluid is not infected in OME as is seen in AOM patients. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. A Religious Media Revolution?

    DEFF Research Database (Denmark)

    Skovgaard-Petersen, Jakob

    2016-01-01

    This article is a preliminary survey of the media usage of Sunni religious actors during the Syrian conflict. It traces the adoption of new media by religious actors, and analyses the kind of authority these actors have sought to embody, whether regime supporting, oppositional or jihadist....... It argues that the conflict has completely altered the means and modes of Sunni religious communication, transforming classical genres and bypassing them with new ones. It concludes that the lack of formal authority in the messaging of the jihadist groupings, and their failed efforts to build up credible...... religious leaders, is a weakness that could well be exploited in the period to come....

  1. Smartphones as locative media

    CERN Document Server

    Frith, Jordan

    2015-01-01

    Smartphone adoption has surpassed 50% of the population in more than 15 countries, and there are now more than one million mobile applications people can download to their phones. Many of these applications take advantage of smartphones as locative media, which is what allows smartphones to be located in physical space. Applications that take advantage of people's location are called location-based services, and they are the focus of this book. Smartphones as locative media raise important questions about how we understand the complicated relationship between the Internet and physical space

  2. Biorelevant dissolution media

    DEFF Research Database (Denmark)

    Ilardia-Arana, David; Kristensen, Henning G; Müllertz, Anette

    2006-01-01

    Biorelevant dissolution media containing bile salt and lecithin at concentrations appropriate for fed and fasted state are useful when testing oral solid formulations of poorly water-soluble drugs. Dilution of amphiphile solutions affects the aggregation state of the amphiphiles because bile salt....... Dilution of the two- and four component media caused enlargement of the mixed micelles and formation of vesicles. The solubility of estradiol in the buffer solution was increased with addition of the amphiphiles. A good correlation (R(2) = 0.987) was found between estradiol solubility and mass...

  3. HTML5 Media

    CERN Document Server

    Powers, Shelley

    2011-01-01

    If you're a web developer or designer familiar with CSS and JavaScript, this tightly focused introduction shows you how to add HTML5 media elements to your web pages, and how to provide custom controls for letting web visitors interact with the content. You'll also learn how to provide subtitles and captions, using file formats that work in browsers now. This book includes code samples and downloadable examples to help you take full advantage of audio and video in your web pages. Ensure your audio or video works in all browsers that support HTML5 media elementsLearn about widely supported me

  4. Hypertextuality and Social Media

    DEFF Research Database (Denmark)

    Albu, Oana Brindusa; Etter, Michael

    2016-01-01

    Texts and conversations are central to the constitution of organizations. Through the use of social media technologies, organizational members and nonorganizational members alike have the capacity to author organizational texts that co-constitute an organization as an entity with a specific...... identity in a situational space and time. The implications of this ability are underexplored. This study focused on how two organizations used the social media technology Twitter to interact with their constituents. The article adopts communication-centered and sociomateriality perspectives to illustrate...

  5. Multisided Media Markets

    DEFF Research Database (Denmark)

    Lindstädt, Nadine

    Media markets recently have been identified as multisided markets. The application of the theory of multisided markets provides a better understanding of such markets. It enriched the hitherto economic approach and led to new insights and perspectives especially for the antitrust authorities when...... evaluating competition constraints and mergers. This paper reviews the theory of multisided markets and subsequently applies it to media markets. Finally the paper draws attention to the new perspectives and insights the theory provides but also brings open research questions to light....

  6. Media and Influence

    Science.gov (United States)

    Bennett, William H.

    The public information media provides information on current events (news), entertainment (programming), and opinions offered by trusted public sources (e.g., business, academic or religious spokespersons, journalists, and government officials). Consequently, it is a major force in shaping a populace's attitudes toward significant social issues and of great interest to intervention planners. The chapter attempts to provide modelers and intervention analysts alike with sufficient understanding of media mechanisms and current research that they can begin contributing to, and benefiting from this important area of study.

  7. Strategy and New Media

    DEFF Research Database (Denmark)

    Plesner, Ursula; Gulbrandsen, Ib Tunby

    2015-01-01

    assumptions in strategy about control, boundaries and choice. To understand their constitutive effects and the implications for strategy-making, it is necessary to develop a research agenda oriented towards understanding technological affordances – but not only in local practices. Due to vital characteristics......Despite current attention to the materiality of organizations and the performative role of tools, devices, artefacts and objects in processes of strategy-making, the impact of new media has not been thoroughly conceptualized in the strategy literature. We argue that new media challenge core...

  8. A new parameterization for waveform inversion in acoustic orthorhombic media

    KAUST Repository

    Masmoudi, Nabil

    2016-05-26

    Orthorhombic anisotropic model inversion is extra challenging because of the multiple parameter nature of the inversion problem. The high number of parameters required to describe the medium exerts considerable trade-off and additional nonlinearity to a full-waveform inversion (FWI) application. Choosing a suitable set of parameters to describe the model and designing an effective inversion strategy can help in mitigating this problem. Using the Born approximation, which is the central ingredient of the FWI update process, we have derived radiation patterns for the different acoustic orthorhombic parameterizations. Analyzing the angular dependence of scattering (radiation patterns) of the parameters of different parameterizations starting with the often used Thomsen-Tsvankin parameterization, we have assessed the potential trade-off between the parameters and the resolution in describing the data and inverting for the parameters. The analysis led us to introduce new parameters ϵd, δd, and ηd, which have azimuthally dependent radiation patterns, but keep the scattering potential of the transversely isotropic parameters stationary with azimuth (azimuth independent). The novel parameters ϵd, δd, and ηd are dimensionless and represent a measure of deviation between the vertical planes in orthorhombic anisotropy. Therefore, these deviation parameters offer a new parameterization style for an acoustic orthorhombic medium described by six parameters: three vertical transversely isotropic (VTI) parameters, two deviation parameters, and one parameter describing the anisotropy in the horizontal symmetry plane. The main feature of any parameterization based on the deviation parameters, is the azimuthal independency of the modeled data with respect to the VTI parameters, which allowed us to propose practical inversion strategies based on our experience with the VTI parameters. This feature of the new parameterization style holds for even the long-wavelength components of

  9. Making Sense of Society Through Social Media

    OpenAIRE

    Axel Bruns

    2015-01-01

    All media are social—they are after all media, in between, intermediating between producers and consumers of content, information, conversation, between the actors in the media and the audiences who read, listen, and watch. And the sociality of the media does not stop there: the processes of media production are social processes just as much as the activities of media audiencing. So strictly speaking, all media are social media. But only a particular subset of all media are fundamentally defi...

  10. Stereotypes in media and media literacy among young people

    National Research Council Canada - National Science Library

    Đerić Ivana; Studen Rajka

    2006-01-01

    ... them so that they may resist different forms of media manipulation. The paper discusses how stereotypes are generated and used by media and the manners in which stereotypical concepts affect young people’s attitudes...

  11. Untitled

    African Journals Online (AJOL)

    seismic anisotropy in the Niger Delta is transversely isotropic with vertical axis of symmetry (VTI). Velocity anisotropy in. VTI media can be modeled by defining ... of high, moderate and low velocity gradient have been identified for the Niger. Delta sediments (Fig. 2). The central part of the study area has a steep increase in.

  12. Against the Media – The Media of Resistance

    OpenAIRE

    Krivak, Marijan

    2013-01-01

    Contemporary praxis of mediation, and a phenomenon usually known as »media theory«, brings with itself the issue of epochal break with traditional culture of textuality, and all inherited ways of knowledge transmission. This represents conceptual narrowing of media to machines for electronic and digital processing of verbal, visual and sonic information. McLuhan`s hot media of print and papers were replaced, at the beginning, by cold media of TV and movies, and finally, by even cooler medi...

  13. New Media and Leadership: Social Media and Open Organizational Communication

    OpenAIRE

    Viorica Pauș

    2013-01-01

    This paper aims to identify and analyze the extent to which new media have penetrated the Romanian organizations’ internal communication and have influenced the leadership. We intend also to consider how social media becomes a tool for organizational communication and contributes to the creation of a new kind of leadership associated with open communication. We start from the premise that new media and social media can contribute to the leader’s mission to create around him a vision and makes...

  14. Using Media Effectively.

    Science.gov (United States)

    Danzer, Gerald A.; Newman, Mark

    1992-01-01

    Recommends that media presentations can be used effectively in the history classroom as images of reality. Suggests films and television programs and documentaries that can be utilized to show how movies play a role in shaping opinion and changing perceptions. (DK)

  15. Social Media in Organizations

    DEFF Research Database (Denmark)

    Razmerita, Liana; Kirchner, Kathrin; Nabeth, Thierry

    2014-01-01

    By using social media, many companies try to exploit new forms of interaction, collaboration, and knowledge sharing through leveraging the social, collaborative dimension of social software. The traditional collective knowledge management model based on a top-down approach is now opening up new a...

  16. New media of urbanity

    Directory of Open Access Journals (Sweden)

    Laurant-Paul Robert

    2003-01-01

    Full Text Available The digital manifestations of city are internet communities, virtual cities and cyberspace as represented in computer games, virtual reality, computer visualisation, digital film etc. Representations of urban space in the new media provide a feedback to physical cities thus becoming a hybrid space.

  17. New media of urbanity

    OpenAIRE

    Laurant-Paul Robert; Vesna Petrešin Robert

    2003-01-01

    The digital manifestations of city are internet communities, virtual cities and cyberspace as represented in computer games, virtual reality, computer visualisation, digital film etc. Representations of urban space in the new media provide a feedback to physical cities thus becoming a hybrid space.

  18. Fiction, Literature and Media

    NARCIS (Netherlands)

    Kooy, Mary; Janssen, Tanja; Watson, Ken

    1999-01-01

    This book examines mother tongue language education and the changing face of the texts that characterise them. In increasingly complex, diverse and media-saturated social contexts, the authors challenge mother tongue teachers and teacher educators to consider and stretch textual horizons to include

  19. Media Embedded Interactions.

    Science.gov (United States)

    Johnson, J. David

    A review of literature and two surveys, one of college students and one of a random sample of adults, were used to examine four aspects of media embedded interactions (social behavior in front of a TV or radio): their functions, their environment, their effects, and the reactions of the interactants to them. Television is seen as performing a…

  20. Femicide in media

    Directory of Open Access Journals (Sweden)

    Mršević Zorica

    2014-01-01

    Full Text Available Media in Serbia explain femicide usually as caused by poverty and alcoholism. This style is gender blind and socially stereotyped because of neglected gender aspects of male violence against women. Particular problem is lack of problematizing obvious social “permission” of male violence. Femicide is regularly presented as an incident, allegedly impossible for anticipation rather than tragic epilogue of long lasting male violence against women which as such exists as a part of traditional gender social relations and roles. Media overlook that alcohol and poverty may only contribute to intensification of already existing, widely accepted domination of men and subordination of women. Media reports as a rule didn’t enter deeper into problems of institutional and social context in which is perpetrated long lasting violence as prefacing femicide. Media also never criticize the social behavior of neighbors, relatives and all others informed on the domestic violence, but rather avoid „mixing“into privacy matters. Thus violence escalates without barriers, eventually developed in femicide, murder a woman, victim of this, decades long lasting violence.

  1. Motivation for media training

    Directory of Open Access Journals (Sweden)

    Anita Mikulič

    2008-12-01

    Full Text Available Readers have been reading more than only texts in books, magazines, newspapers, but also texts in films and TV screens, mobile phones and similar. Moreover, at present we’ve been surrounded by images, which we have yet to learn to read, judge critically and use as a form of articulation. This article, thus, presents useful suggestions for media training.

  2. Electrokinetics in porous media

    NARCIS (Netherlands)

    Luong, D.T.

    2014-01-01

    This thesis presents the PhD research on electrokinetics in porous media. Electrokinetic phenomena are induced by the relative motion between a fluid and a solid surface and are directly related to the existence of an electric double layer between the fluid and the solid grain surface.

  3. New-Media Literacies

    Science.gov (United States)

    Ohler, Jason

    2009-01-01

    Being literate in a real-world sense means being able to read and write using the media forms of the day, whatever they may be. For centuries, consuming and producing words through reading and writing and, to a lesser extent, listening and speaking were sufficient. But because of inexpensive, easy-to-use, and widely available new tools, literacy…

  4. Online Social Media.

    NARCIS (Netherlands)

    Wolfgang Mohr; Leo Kaipiainen; Emmi Maaranen; Tsai Wan-Ying; Morgane Mathieu

    2010-01-01

    In the autumn of 2009, a group of exchange students in the University of Applied Sciences of Utrecht got a task to make a research project on the current situation of Social Media. The group consisted of 5 people with really different backgrounds and opinions. Two Finnish, one Austrian, one Belgian

  5. Social Media Empowerment (III)

    NARCIS (Netherlands)

    A. Cox

    2011-01-01

    full text via link. Synovate heeft de afgelopen twee jaar onderzoek verricht op dit terrein. Anita Cox, Emile Rikken en Stephan van Velthoven zetten op basis daarvan zaken op een rij in een serie van 5 artikelen, hier op Molblog te lezen. In dit artikel staat brand-building via social media

  6. Storytelling met Social Media

    NARCIS (Netherlands)

    René Boonstra

    2011-01-01

    In dit hoofdstuk (7) kijkt René Boonstra naar de rol van social media binnen transmedia storytelling. Vooral de participatiecultuur speelt daarin een belangrijke rol. De vraag waar hij in dit hoofdstuk antwoord op geeft is hoe een communicatieprofessional transmedia storyteling kan gebruiken om het

  7. Cyberbullying via Social Media

    Science.gov (United States)

    Whittaker, Elizabeth; Kowalski, Robin M.

    2015-01-01

    Recent years have witnessed a surge of research on cyberbullying. In this article, three studies examined prevalence rates of cyberbullying among college-age students, venues through which cyberbullying occurs, with a particular focus on social media, and perceptions of cyberbullying as a function of features of the target (e.g., peer, celebrity,…

  8. Modelling Digital Media Objects

    DEFF Research Database (Denmark)

    Troelsgaard, Rasmus

    The goal of this thesis is to investigate two relevant issues regarding computational representation and classification of digital multi-media objects. With a special focus on music, a model for representation of objects comprising multiple heterogeneous data types is investigated. Necessary...

  9. Expanding Media Reach

    Centers for Disease Control (CDC) Podcasts

    2007-11-01

    In this podcast, two nurses serving a Chinese American community show how they have used local ethnic media to communicate health messages.  Created: 11/1/2007 by National Diabetes Education Program (NDEP), a joint program of the Centers for Disease Control and Prevention and the National Institutes of Health.   Date Released: 11/11/2007.

  10. European media law

    NARCIS (Netherlands)

    Castendyk, O.; Dommering, E.; Scheuer, A.

    2008-01-01

    European Union legislation concerning electronic communications media is firmly established as an essential part of the law in the field in Europe. From relevant provisions of the European Convention of Human Rights and the EC Treaty to numerous directives, the most recent being the Audiovisual

  11. Big Data, Small Media

    Directory of Open Access Journals (Sweden)

    Grant Bollmer

    2014-08-01

    Andrew Dubber Radio in the Digital Age Polity, Cambridge, 2013   Charles Ess Digital Media Ethics, Second Edition Polity, Cambridge, 2014   Graeme Kirkpatrick Computer Games and the Social Imaginary Polity, Cambridge, 2013   Dhiraj Murthy Twitter: Social Communication in the Twitter Age Polity, Cambrige, 2013   Jill Walker Rettberg Blogging, Second Edition Polity, Cambridge, 2014

  12. Waves in inhomogeneous media

    NARCIS (Netherlands)

    Gerritsen, S.

    2007-01-01

    In this thesis we study wave propagation in inhomogeneous media. Examples of the classical (massless) waves we consider are acoustic waves (sound) and electromagnetic waves (light, for example). Interaction with inhomogeneities embedded in a reference medium alter the propagation direction, velocity

  13. Islam and Media Representations

    Directory of Open Access Journals (Sweden)

    Mohamed Bensalah

    2006-04-01

    Full Text Available For the author of this article, the media’s treatment of Islam has raised numerous polymorphous questions and debates. Reactivated by the great scares of current events, the issue, though an ancient one, calls many things into question. By way of introduction, the author tries to analyse the complex processes of elaboration and perception of the representations that have prevailed during the past century. In referring to the semantic decoding of the abundant colonial literature and iconography, the author strives to translate the extreme xenophobic tensions and the identity crystallisations associated with the current media orchestration of Islam, both in theWest and the East. He then evokes the excesses of the media that are found at the origin of many amalgams wisely maintained between Islam, Islamism and Islamic terrorism, underscoring their duplicity and their willingness to put themselves, consciously, in service to deceivers and directors of awareness, who are very active at the heart of the politico-media sphere. After levelling a severe accusation against the harmful drifts of the media, especially in times of crisis and war, the author concludes by asserting that these tools of communication, once they are freed of their masks and invective apparatuses, can be re-appropriated by new words and bya true communication between peoples and cultures.

  14. Consolidating Social Media Strategies

    DEFF Research Database (Denmark)

    Gyimóthy, Szilvia; Munar, Ana Maria; Larson, Mia

    2014-01-01

    Gyimóthy & Larson (2014) portrayed three digital value co-creation strategies deployed by festival social media. Both frameworks provided novel analytical typologies which identified a series of categories (mimetic, analytic, immersion, advertising and insourcing, crowdsourcing and community consolidation...

  15. Media and Multiculturalism.

    Science.gov (United States)

    Sugunasiri, Suwanda H. J.

    1983-01-01

    Argues that Canadian media are not more multiculturally sensitive because (1) they are owned and operated by Whites (mostly of British background), who fail to see that Canada's racial composition has changed; and (2) their profit motive restricts social responsiveness. Offers a model of how personal multiculturalism can lead to a multicultural…

  16. Ethics and media

    Directory of Open Access Journals (Sweden)

    Freddy Álvarez

    2008-06-01

    Full Text Available Preguntarse por la ética y los Mass Media,no es fácil. Es una interpelación impregnada de complejidad por la pluralidad de los Media, unida a la dificultad para entender un fenómeno relativamente actual. Además, para lograr acercarnos a una repuesta seria y profunda es importante replantear la ética de otro modo. Los Media, en tanto que tecnologías, como todas las ciencias, debido a la influencia del cartesianismo, han estado fuera de toda relación ética. Quienes los manejan, todavía creen que por pretender a la objetividad y a la neutralidad ya están en la ética. Veamos un poco las derivas en las que ingresan los Media a causa de su disyunción con la ética y los grandes olvidos en los que ha caído, sobre todo en lo que se refiere a la ética y a la verdad.

  17. Corruption in the Media.

    NARCIS (Netherlands)

    Spence, E.H.

    2009-01-01

    Using a general model of corruption that explains and accounts for corruption across different corporate and professional activities, the paper will examine how certain practices in the media, especially in areas where journalism, advertising and public relations regularly intersect and converge,

  18. Mixing in Social Media

    Directory of Open Access Journals (Sweden)

    Bernie Hogan

    2015-04-01

    Full Text Available This essay draws upon the social life of vinyl records as a means to consider social media as a set of many-to-many affordances rather than a suite of technologies. It defines affordances and draws upon their earlier history from cognitive science.

  19. Media Culture and Media Education in Modern School

    Science.gov (United States)

    Tolic, Mirela

    2011-01-01

    Culture is no longer conceivable without the media and/or new phenomena called. "Cyber" culture. The article discusses issues in what respect the different media, like TV, film and Internet are with different cultures, how it changes everyday life under influence of various forms of sophisticated communications media and what…

  20. Need for Orientation, Media Uses and Gratifications, and Media Effects.

    Science.gov (United States)

    Weaver, David

    In order to study the influence of need for orientation and media gratifications on media use and media effects in political communication, two previous surveys were studied to compare the causal modeling approach and the contingent conditions approach. In the first study, 339 personal interviews were conducted with registered voters during a…

  1. Applying East Asian Media Diplomacy Models to African Media: A ...

    African Journals Online (AJOL)

    The last two decades have seen the extensive expansion of South African and Nigerian media on the African continent. However, while the link between media and diplomacy, and the role of media in visualising the state for foreign audiences have received a lot of scholarly attention internationally, relatively little work has ...

  2. Editorial: Pedagogical Media Ecologies

    Directory of Open Access Journals (Sweden)

    Dorothee M. Meister

    2014-07-01

    Full Text Available From educational gaming through portable e-readers to cell phones, media are interpenetrating educational spaces and activities. Accordingly, understanding media in environmental or ecological terms has become increasingly important for education internationally. In North America, for example, the centenary of McLuhan’s birth has focused attention on approaches to media – whether oral, textual, electronic or digital– as a kind of environment in which education takes place. In parts of Europe, the so-called mediatic turn – following on the linguistic and iconic turns – has similarly emphasized the role of media as a condition for the possibility of educational activities and programs. With a few exceptions1 the papers in this special issue were first presented at the conference «Educational Media Ecologies: International Perspectives» which took place at the University of Paderborn, Germany, on March 27–28, 2012.2 The event was an interdisciplinary and transatlantic endeavor to bring together a wide range of perspectives on various issues relevant to educational media ecologies,3 and on related debates on mediation, medialization, mediatization, and mediality.4 The purpose of this volume, like the conference, is to foster and deepen international dialogue in the area of educational media. Areas of research and scholarship relevant to this dialogue include educational media, media literacy, educational philosophy, and media and cultural studies. The contributions, described below, put conceptual issues as well as social practices and applications at the center of the debate. Klaus Rummler opens the issue by clarifying the concept of ecology itself. Referencing a range of work over the past 50 years, Rummler describes how ecological models have been cast in sociological, semiotic, cultural, mediatic and other terms, and he explains the implications of these various perspectives for the study of educational contexts. Rummler also

  3. Assessing the P-wave attenuation and phase velocity characteristics of fractured media based on creep and relaxation tests

    Science.gov (United States)

    Milani, Marco; Germán Rubino, J.; Müller, Tobias M.; Quintal, Beatriz; Holliger, Klaus

    2014-05-01

    Fractures are present in most geological formations and they tend to dominate not only their mechanical but also, and in particular, their hydraulic properties. For these reasons, the detection and characterization of fractures are of great interest in several fields of Earth sciences. Seismic attenuation has been recognized as a key attribute for this purpose, as both laboratory and field experiments indicate that the presence of fractures typically produces significant energy dissipation and that this attribute tends to increase with increasing fracture density. This energy loss is generally considered to be primarily due to wave-induced pressure diffusion between the fractures and the embedding porous matrix. That is, due to the strong compressibility contrast between these two domains, the propagation of seismic waves can generate a strong fluid pressure gradient and associated pressure diffusion, which leads to fluid flow and in turn results in frictional energy dissipation. Numerical simulations based on Biot's poroelastic wave equations are computationally very expensive. Alternative approaches consist in performing numerical relaxation or creep tests on representative elementary volumes (REV) of the considered medium. These tests are typically based on Biot's consolidation equations. Assuming that the heterogeneous poroelastic medium can be replaced by an effective, homogeneous viscoelastic solid, these numerical creep and relaxation tests allow for computing the equivalent seismic P-wave attenuation and phase velocity. From a practical point of view, an REV is typically characterized by the smallest volume for which rock physical properties are statistically stationary and representative of the probed medium in its entirety. A more general definition in the context of wavefield attributes is to consider an REV as the smallest volume over which the P-wave attenuation and phase velocity dispersion are independent of the applied boundary conditions. That is

  4. Third Sector and Social Media

    National Research Council Canada - National Science Library

    Ryan Deschamps; Kathleen McNutt

    2014-01-01

    ... operations. This is no less that case for organizations in the third sector. However, evidence-based practices tying social media activity to social media success are still elusive in the field...

  5. Media life of the young

    DEFF Research Database (Denmark)

    Westlund, Oscar; Bjur, Jakob

    2014-01-01

    This is a thorough investigation into contemporary young people and their media life. The article conceptualizes a typology of media life, drawing on a theoretical body involving the sociology of generations, life course research, media life and individualization. This empirically derived typology...... makes a strong instrument for an understanding of the media life of the young, furnishing insights into how they have constructed their use of media. The investigation is based on a robust national survey with Swedes born 1994–2001, conducted in 2010, and focusing on four media: television, gaming......, the Internet and mobile devices. Two of the findings are particularly surprising. Firstly, the results reveal that the young generally lead heterogeneous media lives, varying with age and sex. Secondly, although some young people literarily live their life in media, there are also de facto young who live...

  6. Media theory: Representations and examples

    National Research Council Canada - National Science Library

    Ovchinnikov, Sergei

    2008-01-01

    In this paper we develop a representational approach to media theory. We construct representations of media by well-graded families of sets and partial cubes and establish the uniqueness of these representations...

  7. Corporate responsibility and the media

    OpenAIRE

    Grayson, David

    2009-01-01

    This paper discusses how CR is covered in the media and the media’s own corporate responsibilities, covering both traditional and new media. Co published with Centrum fur Corporate Citizenship Deutschland

  8. Media independence and dividend policy

    DEFF Research Database (Denmark)

    Farooq, Omar; Dandoune, Salma

    2012-01-01

    Can media pressurize managers to disgorge excess cash to shareholders? Do firms in countries with more independent media follow different dividend policies than firms with less independent media? This paper seeks to answer these questions and aims to document the relationship between media...... for stock market participants. Consequently, stock market participants in emerging markets with more independent media do not demand as high and as much dividends as their counterparts in emerging markets with less independent media. We also show that press independence is more important in defining...... independence and dividend policies in emerging markets. Using a dataset from twenty three emerging markets, we show a significantly negative relationship between dividend policies (payout ratio and decision to pay dividend) and media independence. We argue that independent media reduces information asymmetries...

  9. DISKURSUS ISLAM DALAM KONSTRUKSI MEDIA

    Directory of Open Access Journals (Sweden)

    Muhammad Fahmi

    2015-12-01

    Full Text Available This paper aims to examine how the secular media in Surakarta represent Islam in the case of Charlie Hebdo. Therefore, this study used discourse analysis of Theo van Leeuwen focusing on how the subject or actor of the show in the media. This study concluded that the media represent Islam not only with “Western ideology” through idioms such as radical Islamist militants and terrorists, but also with "Islamic ideology". It is done through the construction of Islam as a religion of moderation and delegitimize Charlie Hebdo as magazine satyr abusing freedom. Various strategies are used ranging from strategy passivation to interdetermination. In this case, there are two poles of attraction in both media, namely the Western and Islamic ideology. If both media are quoting from Western sources, the Western ideology dominates the media narrative. Conversely, when both media used Islamic sources, the influence of Islamic ideology dominates the narrative of both media.

  10. Social media and management fashions

    OpenAIRE

    Madsen, Dag Øivind; Slåtten, Kåre

    2015-01-01

    The management fashion literature has highlighted the role played by business media (i.e. print media outlets) in the diffusion and dissemination of new management concepts and ideas. However, in the last few years, we have witnessed the emergence of social media. Recent research has shown a widespread adoption and usage of social media both in among the general public and professionals in the business community. To date, however, management fashion researchers have not addressed the question...

  11. Documentary Media and Religious Communities

    Directory of Open Access Journals (Sweden)

    Marie-Therese Mäder

    2015-11-01

    Full Text Available The article considers four spaces where media processes involve religious communities and agents: the spaces of production, of representation, of media communication, and of distribution network and institutional framework for circulation. These three spaces systematise the research question posed to the specific source. Furthermore the concept documentary media as viewed from a semio-pragmatic perspective is introduced. Discussion of the commercial series I’m a Mormon shows how different modes define documentary media according to the three spaces.

  12. New Media, Legacy Media and Misperceptions Regarding Sourcing

    Directory of Open Access Journals (Sweden)

    Stan Diel

    2017-07-01

    Full Text Available Resource dependence theory and related theories of management suggest online-only news media may displace legacy news media, but until that happens the two systems are likely to be dependent on the same resource: news. This quantitative content analysis finds that the systems exist as parallel but distinctly separate entities. Websites associated with legacy news media such as newspapers publish mostly hard news or news analysis in the form of original work. New, online-only news media publish mostly unoriginal features, but the origins of much of the content published by onlineonly media are unclear.

  13. Social Media, Traditional Media and Marketing Communication of Public Relations

    DEFF Research Database (Denmark)

    Khajeheian, Datis; Mirahmadi, Fereshteh

    2015-01-01

    Public relations are undertaking more important role in the marketing communication and advertising. The present paper reports a survey conducted in three Iranian banks’ public relations departments to understand how they use different media in their marketing communications and other related......, Social media and finally Mobile and SMS ads. Findings show that traditional media still play a dominant role in media consumption of public relations, while new Web2.0 media consist of Mobile communications and Social networks, have never ranked better than fifth from eight. Some reasons have been argues...

  14. Media violence and youth behaviour

    African Journals Online (AJOL)

    QuickSilver

    2003-05-07

    May 7, 2003 ... Villani S. Impact of Media on Children and Adolescents: A 10-Year. Review of the Research. J Am Acad ... Strasburger VC, Donnerstein E. Children, adolescents, and the media in the 21 st century. Adolesc ... video and computer games as well computers and the internet.(1). In addition, print media in the ...

  15. SPORTS JOURNALISM AND MEDIA RESEARCH

    Directory of Open Access Journals (Sweden)

    Velizar Sredanović

    2008-08-01

    Full Text Available Communicology theoreticians, sociologists, and sports experts strive to explain significance of sport, power and influence of media (TV in particular and sports journalism through analysis of media and viewers. Phenomena observed on number of football (soccer and Olympic games through a prism of media research of the Television of Montenegro.

  16. Media Violence and Young People.

    Science.gov (United States)

    Oaks, Harold R.

    1995-01-01

    Discusses the possibility of a connection between violence in the media and actual adolescent behavior. Explores the nature of the connection, why it exists, and possible courses of action to correct the problem. States that 3,000 studies have explored the link between media violence and adolescent behavior. Concludes that the media should show…

  17. Transmedia Play: Literacy across Media

    Science.gov (United States)

    Alper, Meryl; Herr-Stephenson, Rebecca

    2013-01-01

    Transmedia play is a new way to understand how children develop critical media literacy and new media literacies through their interactions with contemporary media that links stories and structures across platforms. This essay highlights five characteristics of transmedia play that make it particularly useful for learning:…

  18. REPORT ON UNDERSTANDING NEW MEDIA.

    Science.gov (United States)

    MCLUHAN, MARSHALL

    IN TYPICAL MCLUHAN STYLE, THE AUTHOR OF THIS WORKING PAPER TRACES HISTORICAL-CULTURAL TRANSITIONS FROM PHONETIC ALPHABET TECHNOLOGY TO MEDIA OF THE NEW ELECTRONIC TECHNOLOGY. THESE MEDIA ARE VIEWED AS EXTENSIONS OF MAN'S SENSES, AND AS LANGUAGES THEMSELVES, WHOSE ONLY CONTENT ARE OTHER MEDIA. EACH MEDIUM (E.G. SPEECH, WRITING, PRINT, PHOTOGRAPHY,…

  19. Social media and activist communication

    NARCIS (Netherlands)

    Poell, T.; van Dijck, J.; Atton, C.

    2015-01-01

    While the rise of social media has made activists much less dependent on television and mainstream newspapers, this certainly does not mean that activists have more control over the media environments in which they operate. Media power has neither been transferred to the public, nor to activists for

  20. Media Competition and Electoral Politics

    NARCIS (Netherlands)

    Piolatto, A.; Schuett, F.

    2013-01-01

    Abstract: We build a framework linking competition in the media market to political participation, media slant, and selection of politicians. Media outlets report on the ability of candidates running for office and compete for audience through their choice of slant. Citizens derive utility from

  1. Stereotypes in media and media literacy among young people

    Directory of Open Access Journals (Sweden)

    Đerić Ivana

    2006-01-01

    Full Text Available Young people, the most common consumers of media content, bear out the view that media shapes people’s lives. Therefore we must not underestimate the effect media exerts on young people’s values and behavioral patterns. Television is the medium which draws children and young people for the greatest part of their free time. Regardless whether television programs are described as positive or negative, whether they abound with stereotypes or not, it is important that young people develop a critical attitude towards them so that they may resist different forms of media manipulation. The paper discusses how stereotypes are generated and used by media and the manners in which stereotypical concepts affect young people’s attitudes. It highlights the importance of the development of media literacy which implies a critical attitude towards media images and discourses, the development of criteria for the selection and evaluation of information broadcast by media, the development of skills in interpreting and understanding stereotypical concepts and familiarity with alternative forms of media culture. The paper draws special attention to the issue of media education. The conclusion is that schools should offer media literacy as part of their curriculum and in it possible solutions to the problems discussed. .

  2. Komunikasi dan Media Sosial (Communications and Social Media

    Directory of Open Access Journals (Sweden)

    Errika Dwi Setya Watie

    2016-03-01

    Full Text Available Media presents to be a part of human life. The presence and the development of internet bring a new way of how to communite in social life. Social media presents and changes the communication paradigm in today's society. Communication in social media is not limited by distance, time, and space. It could happen anywhere, anytime, without having a face to face talking. Even social media can negate social status that is often as a barrier in communication. Social media has changed the world. Levels of communication merged into one container called a social media. The rise of many consequences must also be wary of, in the sense of social media opens up the opportunity of each individual involved in it to issue his opinion freely. However, self-control should be shared, in order to have freedom of communication which does not violate ethical boundaries and does not offend others.

  3. Social Media Marketing

    DEFF Research Database (Denmark)

    Hollensen, Svend; Kotler, Philip; Opresnik, Marc Oliver

    Marketing communication is undergoing a digital revolution. The increasing popularity of blogging, podcasting, and social networks enables world customers to broadcast their views about a product or service to a potential audience of billions. Traditional advertising does not work as well as it has...... in the past. This book on ‘Social Media Marketing’ guides through the maze of communities, platforms, and social media tools so that markers can decide which ones to use, and how to use them most effectively. With an objective approach and clear, straightforward language, it shows how to plan and implement...... campaigns intelligently, and then measure results and track return on investment. For beginners overwhelmed by too many choices as well as seasoned professionals eager to improve their game, this comprehensive book is full of tactics that have been proven to work in the real marketing world. This book...

  4. Subsidizing Media Innovation

    DEFF Research Database (Denmark)

    Kammer, Aske; Hobel, Emil

    and economically sustainable activity, the institutionalization of financial support for media innovation constitute one way for policy makers to bring (parts of) the journalistic environment up-to-date with the digital age, thereby improving the conditions for an informed citizenry in the future (Kammer......, forthcoming/2016). Theoretically, the paper draws upon the normative foundation of the social-democratic welfare state (found in the Scandinavian countries; cf. Esping-Andersen, 1990) to provide a framework for measuring the ambition, implementation, and impact of the innovation fund. So, this paper......). Qualitative Media Analysis (2nd Ed.). Los Angeles: Sage. Esping-Andersen, G. (1990). The Three Worlds of Welfare Capitalism. Cambridge: Polity Press. Kammer, A. (forthcoming/2016). Market Structure and Innovation Policies in Denmark. In H. v. Kranenburg (Ed.), Innovation Policies in the European News...

  5. [Mental illness and media].

    Science.gov (United States)

    Magli, Erica; Buizza, Chiara; Pioli, Rosaria

    2004-06-01

    Many knowledges on the mental disease that the community possesses are turning out of information disclosed from the media. It's common in the press to connect actions of violence and murders to the mental diseases. For this reason, the reader is induced to infer that murders and other violent actions are more frequent in people who have suffered from mentally ill, than in the general population. The mystifying impression provided by media accrues from the fact that these reports are rarely compensated from positive reports. Objective of the present study is to characterize the type of information concerning mental illness diffused from the local daily paper "Giornale di Brescia" in the year 2001. The results show that many articles connote negatively the mental disease. The journalistic sensationalism, denounced facing the speech of the prejudgment in the comparisons of the mentally ill people, seems to still remain, in the considered year of publication, one unchanging tendency.

  6. Culinary art in media

    Directory of Open Access Journals (Sweden)

    Radojičić Dragana

    2009-01-01

    Full Text Available The subject of diet culture is beyond the scope of this paper. Therefore, I concentrated on several examples which best illustrate the presence of culinary art and diet in media. That is, I used 72 articles from the magazine Gloria with the food subject (2006-2009. Diet and culinary arts are omnipresent in media globally. As a rule, many offers recommend recipes and items considered traditional, with a wide range of recipes offered in Serbia alone. Internet also offers many web sites with various diets and recipes. All in all, domestic readers of local journals and magazine can find a variety of fashionable recipes from all over the world, most of the time with limited instructions or groceries not easily obtained at the local market. Bon ton is also lacking while diet and food choices continue to saturate all forms of social behavior as well as recipes serving as communication within a given culture.

  7. Trust in media information

    Directory of Open Access Journals (Sweden)

    Miquel Rodrigo

    2003-06-01

    Full Text Available For Miquel Rodrigo, cultural diversity places informative discourse in a crisis because it needs new categories to explain reality, and these categories are not always shared by journalists and by those who receive the information. Instead of gaining an easy trust drawnfrom stereotypes, he proposes, as a better way of overcoming the crisis, fostering the existence of sceptical readers. The media interprets social phenomena with its personal and professional limitations. The sceptical reader is one who knows why the media says what it says and understands that its truths are not absolute, since all ways of seeing are ways of concealing. The relationship between scepticism and trust is that which opposes a blind, acrylic and capitulating trust.

  8. Media evolution and ‘epi-technic’ digital media: Media as cultural selection mechanisms

    DEFF Research Database (Denmark)

    Olesen, Mogens

    2016-01-01

    The explosive development of new digital media technologies is often described as a media evolution but hardly ever is the concept of ‘media evolution’ taken at face value. This article takes up that challenge by combining cultural evolution theories with medium theory. The article argues that bi...

  9. Femicide in media

    OpenAIRE

    Mršević Zorica

    2014-01-01

    Media in Serbia explain femicide usually as caused by poverty and alcoholism. This style is gender blind and socially stereotyped because of neglected gender aspects of male violence against women. Particular problem is lack of problematizing obvious social “permission” of male violence. Femicide is regularly presented as an incident, allegedly impossible for anticipation rather than tragic epilogue of long lasting male violence against women which as such ...

  10. 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......, copyright, sex and violence online, and global citizenship). The book has become one of two "must-reads" in the United States for anyone interested in these topics....

  11. Advertising in Arabic media

    OpenAIRE

    Al Hamatiová, Arwa

    2008-01-01

    My diploma thesis deals with the analysis of advertising in Arabic media, in particular in Arabic TV stations, such as MBC1, MBC2 and Dubai One. It is based on structuring advertising with respect to content and aim of the statement, i. e. classifying advertising either as product advertisement, image advertising, or social advertising. The thesis studies the advertising style in the fields of lexicology, morphology, and syntax; it however looks also at promotional strategy and persuasion met...

  12. Michael Faraday, media man.

    Science.gov (United States)

    Fara, Patricia

    2006-03-01

    Michael Faraday was an enthusiastic portrait collector, and he welcomed the invention of photography not only as a possible means of recording observations accurately, but also as a method for advertising science and its practitioners. This article (which is part of the Science in the Industrial Revolution series) shows that like many eminent scientists, Faraday took advantage of the burgeoning Victorian media industry by posing in various roles.

  13. Dialysis and contrast media

    Energy Technology Data Exchange (ETDEWEB)

    Morcos, Sameh K. [Department of Diagnostic Imaging, Northern General Hospital, Sheffield Teaching Hospitals NHS Trust, Sheffield S5 7AU (United Kingdom); Thomsen, Henrik S. [Department of Diagnostic Radiology 54E2, Copenhagen University Hospital at Herlev, Herlev Ringvej 75, 2730 Herlev (Denmark); Webb, Judith A.W. [Department of Diagnostic Imaging, St Bartholomew' s Hospital, London EC1A 7BE (United Kingdom)

    2002-12-01

    In a previous survey we revealed uncertainty among responders about (a) whether or not to perform hemodialysis in patients with severely reduced renal function who had received contrast medium; and (b) when to perform hemodialysis in patients on regular treatment with hemodialysis or continuous ambulatory dialysis who received contrast medium. Therefore, the Contrast Media Safety Committee of The European Society of Urogenital Radiology decided to review the literature and to issue guidelines. The committee performed a Medline search. Based on this, a report and guidelines were prepared. The report was discussed at the Ninth European Symposium on Urogenital Radiology in Genoa, Italy. Hemodialysis and peritoneal dialysis safely remove both iodinated and gadolinium-based contrast media. The effectiveness of hemodialysis depends on many factors including blood and dialysate flow rate, permeability of dialysis membrane, duration of hemodialysis and molecular size, protein binding, hydrophilicity, and electrical charge of the contrast medium. Generally, several hemodialysis sessions are needed to removal all contrast medium, whereas it takes 3 weeks for continuous ambulatory dialysis to remove the agent completely. There is no need to schedule the dialysis in relation to the injection of iodinated or MR contrast media or the injection of contrast agent in relation to the dialysis program. Hemodialysis does not protect poorly functioning kidneys against contrast-medium-induced nephrotoxicity. Simple guidelines are given. (orig.)

  14. Social Media Marketing

    DEFF Research Database (Denmark)

    Hollensen, Svend; Raman, Anthony

    2014-01-01

    Social media marketing can be understood as a group of Internet-based applications that build on the foundations of Web 2.0 and that then allows the creation and exchange of ‘User Generated Content’. In the ‘Bowling’ marketing world, marketers target certain customer groups and send out...... this is a very direct one-way communication approach. In a social media marketing world, the bowling metaphor does not fit anymore. On this arena marketing can be better described as playing “Pinball”: Companies serve up a “marketing ball” (brands and brand-building messages) into a dynamic and chaotic market...... environment. The “marketing ball” is then diverted and often accelerated by social media “bumpers”, which change the ball’s course in chaotic ways. Occasionally, the marketing ball will come back to the company. At this point, the firm (brand) has to use the flippers to interact and throw it back...

  15. Poroelasticity of high porosity chalk under depletion

    DEFF Research Database (Denmark)

    Andreassen, Katrine Alling; Fabricius, Ida Lykke

    2013-01-01

    on mechanical test results is found to be low-er than the pretest dynamic Biot coefficient determined from elastic wave propagation for the loading path and with less deviation under depletion. The calculated lateral stress is lower than the experimentally measured lateral stress depending on loading path...

  16. MEDIA ENTREPRENEURSHIP: A CONSENSUAL DEFINITION

    Directory of Open Access Journals (Sweden)

    DATIS KHAJEHEIAN

    Full Text Available ABSTRACT Media Entrepreneurship has been an ambiguous, unclear and controversial concept and despite of growing academic efforts in the last decade, it is still a poorly defined subject. This paper is an effort to fill this gap by providing a comprehensive definition of media entrepreneurship. Firstly, a literature review conducted and entrepreneurship, media, opportunity and innovation as building blocks of media entrepreneurship explained. Then by using of a mixed of bibliographic method and a Delphi method with multi-stage analysis process, a consensual definition of media entrepreneurship proposed. This definition integrates some key features of the emerging media environment such as distinction of content and platform, value delivery, opportunity development, non-monetary benefit, etc. It is expected that the findings of this research clear the ground for further researches in the field of media entrepreneurship.

  17. Information Provenance in Social Media

    Science.gov (United States)

    Barbier, Geoffrey; Liu, Huan

    Information appearing in social media provides a challenge for determining the provenance of the information. However, the same characteristics that make the social media environment challenging provide unique and untapped opportunities for solving the information provenance problem for social media. Current approaches for tracking provenance information do not scale for social media and consequently there is a gap in provenance methodologies and technologies providing exciting research opportunities for computer scientists and sociologists. This paper introduces a theoretical approach aimed guiding future efforts to realize a provenance capability for social media that is not available today. The guiding vision is the use of social media information itself to realize a useful amount provenance data for information in social media.

  18. Civic Engagement and Social Media

    DEFF Research Database (Denmark)

    The recent wave of protests, from the Arab Spring to the Occupy movement and austerity protests, have reinvigorated hopes for the democratic potential of the Internet, and particularly social media. With their popular appeal and multimodal affordances social media such as YouTube, Twitter...... and Facebook have generated both media and scholarly interest in their possibilities for granting visibility to and facilitating the organization of activism. However, the role of social media in sustaining civic engagement beyond protest and fatalism remains under-explored. How can social media contribute...... to sustaining longer-term involvement of civil society? What is the potential of social media for making available alternative social imaginaries? And what role may social media play in facilitating social change through cooperation with business? This volume offers answers to these questions by providing...

  19. Cognitive control in media multitaskers

    Science.gov (United States)

    Ophir, Eyal; Nass, Clifford; Wagner, Anthony D.

    2009-01-01

    Chronic media multitasking is quickly becoming ubiquitous, although processing multiple incoming streams of information is considered a challenge for human cognition. A series of experiments addressed whether there are systematic differences in information processing styles between chronically heavy and light media multitaskers. A trait media multitasking index was developed to identify groups of heavy and light media multitaskers. These two groups were then compared along established cognitive control dimensions. Results showed that heavy media multitaskers are more susceptible to interference from irrelevant environmental stimuli and from irrelevant representations in memory. This led to the surprising result that heavy media multitaskers performed worse on a test of task-switching ability, likely due to reduced ability to filter out interference from the irrelevant task set. These results demonstrate that media multitasking, a rapidly growing societal trend, is associated with a distinct approach to fundamental information processing. PMID:19706386

  20. New media coming to Vumilia

    DEFF Research Database (Denmark)

    Gustafsson, Jessica

    2017-01-01

    the two can impact on the connectivity, at least on individual level. This chapter will focus on how media ecologies are currently changing in Vumilia, a rural village that was connected to the power grid less than three years ago. It will touch upon and point to important aspect that shape people’s media...... that has recently become available to them? How has the introduction of new media technology changed existing media ecologies and helped the creation of new media ecologies?......In the last two decades, the media landscape has changed rapidly in Kenya. In the 1990s, the Kenyan media market was deregulated, resulting in a substantial increase of private FM stations and TV stations. In recent years, the enormous uptake of mobile telephones has taken place parallel...

  1. Media Literacy: 21st Century Learning

    Science.gov (United States)

    Baker, Frank W.

    2011-01-01

    The media, for better or worse, deliver the news and the gossip; they entertain, educate and inform. The media have not always been in American classrooms. Yes, teachers teach with media, but rarely do they teach "about" the media. It's called media literacy. Most students are not receiving adequate media literacy instruction, mostly because their…

  2. Characteristics of Media Audiences and Trust in the media

    Directory of Open Access Journals (Sweden)

    Antonija Čuvalo

    2010-12-01

    Full Text Available This article analyzes elements of the social and demographic profi le of Croatian media audiences in order to identify what may determine their perceptions of the Croatian media and their overall trust in the media. The analytical data that forms the foundation of this examination derives from the research project, “Trust in Media”, ordered by the Faculty of Political Science at the University in Zagreb and conducted in co-operation with the Zagreb-based research agency Media Metar, on nationally representative probability samples. The main assumption is that the diff erences in demographic characteristics and cultural capital within media audiences affect personal attitudes toward media institutions and overall trust in the media. Emphasis is allotted to the differences in professional qualifications, as an indicator of cultural capital, as well as on the diff erences in other social and demographic characteristics and on the relationship of media consumption and trust in media. Relying on the results of previous studies, this article examines the extent of which perception and trust in the media may be explained by differences in social and demographic characteristics.

  3. A recipe for practical full waveform inversion in anisotropic media

    KAUST Repository

    Alkhalifah, Tariq Ali

    2014-03-28

    In representing the most common (first-order influence, and gravity induced) acoustic anisotropy, transversely isotropic with a vertical symmetry direction (VTI) medium, with the P-wave normal moveout velocity, delta, and eta, we obtain a perturbation radiation pattern that has limited tradeoff between the parameters. Since delta is weakly resolvable from the kinematics of wave propagation, we can use it to play the role that density plays in improving the data fit for an imperfect physical model that ignores the elastic nature of the Earth. An FWI scheme that starts from diving waves would benefit from representing the acoustic VTI model with the P-wave horizontal velocity, eta, and epsilon. In this representation, the diving waves will help us first resolve the horizontal velocity, and then reflections, if the nonlinearity is properly handled, could help us resolve eta, while epsilon comes at the end to improve the amplitude fit (instead of the density). The model update wavelength for acoustic anisotropic FWI is very much similar to that experienced for the isotropic case. Copyright © 2014 by the European Association of Geoscientists & Engineers. All rights reserved.

  4. Media identities and media-influenced indentifications Visibility and identity recognition in the media

    Directory of Open Access Journals (Sweden)

    Víctor Fco. Sampedro Blanco

    2004-10-01

    Full Text Available The media establish, in large part, the patterns of visibility and public recognition of collective identities. We define media identities as those that are the object of production and diffusion by the media. From this discourse, the communities and individuals elaborate media-influenced identifications; that is, processes of recognition or banishment; (rearticulating the identity markers that the media offer with other cognitive and emotional sources. The generation and appropriation of the identities are subjected to a media hierarchisation that influences their normalisation or marginalisation. The identities presented by the media and assumed by the audience as part of the official, hegemonic discourse are normalised, whereas the identities and identifications formulated in popular and minority terms are marginalised. After presenting this conceptual and analytical framework, this study attempts to outline the logics that condition the presentation, on the one hand, andthe public recognition, on the other hand, of contemporary identities.

  5. Post Media Literacy: Menyaksikan Kuasa Media Bersama Michel Foucault

    Directory of Open Access Journals (Sweden)

    Iswandi Syahputra

    2017-01-01

    Full Text Available This article would like to present Michel Foucault’s idea concerning Knowledge and Power in media industry. As a contemporary intellectual, Foucault’s thought has a unique style of postmodernism. His thought had gone beyond traditional critical theory whose trying to disclose the relation of power and economic behind the ideology of media. Foucault’s thought had given new perspective in understanding how the media produce truth under tightly control process into something that seems normal. With the assumption of media has the power to create mass culture, which has to be studied critically by media literacy approach, Foucault’s thought had given new space of discursive. An alternative thought on how to estimate the work of mass media as supervisor of truth and creator of information trough normalization practice.

  6. New media and tobacco control.

    Science.gov (United States)

    Freeman, Becky

    2012-03-01

    This paper reviews how the tobacco industry is promoting its products online and examines possible regulation models to limit exposure to this form of marketing. Opportunities to use new media to advance tobacco control are also discussed and future research possibilities are proposed. Published articles and grey literature reports were identified through searches of the electronic databases, PUBMED and Google Scholar using a combination of the following search terms: tobacco or smoking and new media, online media, social media, internet media, Web 2.0, Facebook, YouTube and Twitter. A possible obstacle to fully realising the benefits of regulating tobacco marketing activities and effectively communicating tobacco control messages is the rapid evolution of the media landscape. New media also offer the tobacco industry a powerful and efficient channel for rapidly countering the denormalising strategies and policies of tobacco control. Evidence of tobacco promotion through online media is emerging, with YouTube being the most researched social media site in the tobacco control field. The explosive rise in Internet use and the shift to these new media being driven by consumer generated content through social platforms may mean that fresh approaches to regulating tobacco industry marketing are needed.

  7. Characteristics of Media Audiences and Trust in the media

    OpenAIRE

    Antonija Čuvalo

    2010-01-01

    This article analyzes elements of the social and demographic profi le of Croatian media audiences in order to identify what may determine their perceptions of the Croatian media and their overall trust in the media. The analytical data that forms the foundation of this examination derives from the research project, “Trust in Media”, ordered by the Faculty of Political Science at the University in Zagreb and conducted in co-operation with the Zagreb-based research agency Media Metar, on nation...

  8. Crafting digital media

    CERN Document Server

    James, Daniel

    2010-01-01

    Open source software, also known as free software, now offers a creative platform with world-class programs. Just ask the people who have completed high-quality projects or developed popular web 2.0 sites using open source desktop applications. This phenomenon is no longer underground or restricted to techies - there have been more than 61 million downloads of the Audacity audio editor and more than 60 million downloads of the GIMP for Windows photographic tool from SourceForge.net alone. Crafting Digital Media is your foundation course in photographic manipulation, illustration, animation, 3D

  9. Media Bias and Reputation

    OpenAIRE

    Matthew Gentzkow; Shapiro, Jesse M.

    2005-01-01

    A Bayesian consumer who is uncertain about the quality of an information source will infer that the source is of higher quality when its reports conform to the consumer's prior expectations. We use this fact to build a model of media bias in which firms slant their reports toward the prior beliefs of their customers in order to build a reputation for quality. Bias emerges in our model even though it can make all market participants worse off. The model predicts that bias will be less severe w...

  10. Subsidizing Media Innovation

    DEFF Research Database (Denmark)

    Kammer, Aske; Hobel, Emil

    and economically sustainable activity, the institutionalization of financial support for media innovation constitute one way for policy makers to bring (parts of) the journalistic environment up-to-date with the digital age, thereby improving the conditions for an informed citizenry in the future (Kammer......, forthcoming/2016). Theoretically, the paper draws upon the normative foundation of the social-democratic welfare state (found in the Scandinavian countries; cf. Esping-Andersen, 1990) to provide a framework for measuring the ambition, implementation, and impact of the innovation fund. So, this paper...

  11. Pemberitaan Media Pers Indonesia

    Directory of Open Access Journals (Sweden)

    Ashadi Siregar

    2006-03-01

    Full Text Available New freedom and democratic atmosphere existing in Indonesia allow the Indonesian press enjoys its new significant position. This can expand the Indonesian press goals, particularly in enriching the industrial aspiration of the institution. However, bearing in mind that Indonesia is a multicultural country, the Indonesian press can also strengthen the various demographic backgrounds of the state leading to the unity of Indonesia. This article discusses four points of the Indonesian press that need to he considered by the mass media professionals.

  12. Towards a Media Architecture

    DEFF Research Database (Denmark)

    Ebsen, Tobias

    2010-01-01

    This text explores the concept of media architecture as a phenomenon of visual culture that describes the use of screen-technology in new spatial configurations in practices of architecture and art. I shall argue that this phenomenon is not necessarily a revolutionary new approach, but rather...... a result of conceptual changes in both modes visual representation and in expressions of architecture. These are changes the may be described as an evolution of ideas and consequent experiments that can be traced back to changes in the history of art and the various styles and ideologies of architecture....

  13. Making media public

    DEFF Research Database (Denmark)

    Mollerup, Nina Grønlykke; Gaber, Sherief

    2015-01-01

    This article focuses on two related street screening initiatives, Tahrir Cinema and Kazeboon, which took place in Egypt mainly between 2011 and 2013. Based on long-term ethnographic studies and activist work, we explore street screenings as place-making and describe how participants at street scr...... because they made media engage with and take place within everyday spaces that the revolution aims to liberate and transform, and because the screenings’ public and illegal manner at times embodied events portrayed in the images....

  14. Social media and management fashions

    Directory of Open Access Journals (Sweden)

    Dag Øivind Madsen

    2015-12-01

    Full Text Available The management fashion literature has highlighted the role played by business media (i.e. print media outlets in the diffusion and dissemination of new management concepts and ideas. However, in the last few years, we have witnessed the emergence of social media. Recent research has shown a widespread adoption and usage of social media both in among the general public and professionals in the business community. To date, however, management fashion researchers have not addressed the question of whether social media change the structure and workings of the management fashion market and the ways in which management concepts and ideas are diffused. This article provides a preliminary conceptual elaboration and analysis of how different social media platforms may influence the diffusion and dissemination of fashionable concepts and ideas. The analysis has several implications for research on management fashion.

  15. Climate News Across Media Platforms

    DEFF Research Database (Denmark)

    Eskjær, Mikkel Fugl

    2015-01-01

    In a changing media landscape marked by technological, institutional and cultural convergence, comparative and cross-media content analysis represents a valuable analytical tool in mapping the diverse channels of climate change communication. This paper presents a comparative study of climate...... quantitative and qualitative content analysis the paper documents and explores the extent and character of climate change news across different media platforms. The study aims at contributing to the on-going assessment of how news media are addressing climate change at a time when old and new media...... change news on five different media platforms: newspapers, television, radio, web-news and mobile news. It investigates the themes and actors represented in public climate change communication as well as the diverse possibilities of participating in public debates and information sharing. By combining...

  16. Media Effects: Theory and Research.

    Science.gov (United States)

    Valkenburg, Patti M; Peter, Jochen; Walther, Joseph B

    2016-01-01

    This review analyzes trends and commonalities among prominent theories of media effects. On the basis of exemplary meta-analyses of media effects and bibliometric studies of well-cited theories, we identify and discuss five features of media effects theories as well as their empirical support. Each of these features specifies the conditions under which media may produce effects on certain types of individuals. Our review ends with a discussion of media effects in newer media environments. This includes theories of computer-mediated communication, the development of which appears to share a similar pattern of reformulation from unidirectional, receiver-oriented views, to theories that recognize the transactional nature of communication. We conclude by outlining challenges and promising avenues for future research.

  17. MEDIA TECHNOLOGIES IN TEACHING PHILOSOPHY

    Directory of Open Access Journals (Sweden)

    Elena Grednovskaya

    2016-12-01

    Full Text Available This article describes the experience of the Department of Philosophy of the South Ural State University (Russia on the use of media technology in the teaching of philosophy. Media technologies are examined not simply as tools of knowledge translation to students, but they are comprehended as a media reality, which sometimes completely dissolve a human. Media philosophy which appeared as a new philosophical trend that meets the today realities, contemplates the nowadays situation of influence of mass communications on human’s world outlook, on his selfidentification, also on his body and feelings. The students are possessed to analyze a visual media material, because the foundation of media reality is a visual image.

  18. Does social media reduce 'corporate media influence' on journalism?: The Case of Turkish Media

    Directory of Open Access Journals (Sweden)

    Ceren Sozeri

    2011-12-01

    Full Text Available McChesney described one of the biggest problem of journalism as “the journalists have any power to be autonomous from owners and advertisers” (2008:58. Most of media market have been dominated by a few media companies, furthermore a few media conglomerates who had expanded with merger and acquisitions transactions control the biggest part of the global media and entertainment industry. This concentration of media power and penetration of commercial interest in the news media has been seen as affecting the mode of news, profession of journalism and outputs, and consequently, diversity and democracy itself. research aims to examine the potential of social media to create autonomous spaces for journalists working under the commercial pressure of their corporation. In order to analyze this new kind of news area for journalism, three different qualitative methods are used in different steps of research. First, social media utterances of popular journalists were observed to reveal their journalistic intention and they were also evaluated using two case stud- ies about social events which had been tweeted multiple times for many Turkish users (trending topics in Twitter’s agenda. After diversifying the sample, different types of journalists’ social media experiments, including their responsibility to corporations, were examined by qualitative methods including in-depth interviews. Our findings show that although interactions between the journalists and audience observably changed, Twitter, as with other social networks, didn’t diminish the influence of corporate interests on journalism in Turkish media organisations.

  19. LIBRARIES, SOCIAL MEDIA AND METRICS

    Directory of Open Access Journals (Sweden)

    Nieves González Fernández-Villavicencio

    2016-02-01

    Full Text Available This paper is an abstract of the dissertation Profitability of a library using social media and highlights research carried out in order to demonstrate the profitability of libraries that make use of social media both to offer products and services to the users in line with their expectations and needs and to deliver different types of ROI. A set of social media indicators to measure the evolution and results has also been established.

  20. LIBRARIES, SOCIAL MEDIA AND METRICS

    OpenAIRE

    Nieves González Fernández-Villavicencio

    2016-01-01

    This paper is an abstract of the dissertation Profitability of a library using social media and highlights research carried out in order to demonstrate the profitability of libraries that make use of social media both to offer products and services to the users in line with their expectations and needs and to deliver different types of ROI. A set of social media indicators to measure the evolution and results has also been established.

  1. Electronic cigarettes in the media

    OpenAIRE

    Payne, J. Drew; Orellana-Barrios, Menfil; Medrano-Juarez, Rita; Buscemi, Dolores; Nugent, Kenneth

    2016-01-01

    Electronic cigarettes (e-cigarettes) are an increasingly popular source of nicotine and an increasingly popular topic in the media. Concerns about potential hazards associated with e-cigarette use and advertising, especially to adolescents, have led to studies on e-cigarettes in both traditional media (TV, mail, print, and outdoor advertising) and social media (websites, social networking sites, blogs, and e-mails). This review presents a narrative description of available studies related to ...

  2. MEDIA INFLUENCE ON OPERATIVE SITUATION

    OpenAIRE

    Mikhail M. Ardavov

    2016-01-01

    The problems regarding the influence of the media on various aspects of society are viewed in the article. Historical facts of the media influence on large groups of people are given. Concerning the discussed problem views on the concept of operative situation are set out. Analysis of factors affecting the operative situation is given. Based on the analysis of publications devoted to the problem of the media influence on the processes in society, a generalization of areas of their impact on t...

  3. Quantifying Controversy in Social Media

    OpenAIRE

    Garimella, Kiran; Morales, Gianmarco De Francisci; Gionis, Aristides; Mathioudakis, Michael

    2015-01-01

    Which topics spark the most heated debates on social media? Identifying those topics is not only interesting from a societal point of view, but also allows the filtering and aggregation of social media content for disseminating news stories. In this paper, we perform a systematic methodological study of controversy detection by using the content and the network structure of social media. Unlike previous work, rather than study controversy in a single hand-picked topic and use domain specific ...

  4. Verbal behavior and social media

    OpenAIRE

    Lillemoen, Maria

    2013-01-01

    Social interaction is important for human beings and has been subject for research in different forms. Due to technological developments the last decade, social media have occurred and show social interaction in new forms. With the background in social media and the key concept of interaction, these articles offer a behavior analytic view of understanding interaction in social media. The first article presents Web 2.0 and interaction viewed from traditional approach and functional approach. T...

  5. Verbal behavior and social media

    OpenAIRE

    Lillemoen, Maria

    2013-01-01

    Master i læring i komplekse systemer Social interaction is important for human beings and has been subject for research in different forms. Due to technological developments the last decade, social media have occurred and show social interaction in new forms. With the background in social media and the key concept of interaction, these articles offer a behavior analytic view of understanding interaction in social media. The first article presents Web 2.0 and interaction viewed from traditi...

  6. Studying Normal, Everyday Social Media

    OpenAIRE

    Daren C. Brabham

    2015-01-01

    Social media research has tended to focus on stand-out cases and has made use of big data methods to make claims about human experience and sociality. This commentary urges researchers to consider the everyday, normal experiences of most social media users, to consider the place of social media in a broader social context, and to consider marrying big data approaches with interviews and surveys of users.

  7. Social Media as Leisure Culture

    DEFF Research Database (Denmark)

    Albrechtslund, Anne-Mette Bech; Albrechtslund, Anders

    2014-01-01

    The main idea of this article is to situate social media practices in broader cultural practices. We point to certain dynamics in social media practices which we connect to the culture of 20th century mass tourism. This gives us a nuanced understanding of the activities connecting everyday life...... and social media. Further, our analysis provides new insights into the basic motivation for engaging in online sociality despite concerns about privacy, time-waste and exploitation....

  8. Media Capture and Wealth Concentration

    OpenAIRE

    Corneo, Giacomo

    2003-01-01

    While objective news coverage is vital to democracy, media bias can seriously distort collective decisions. This Paper develops a voting model where citizens are uncertain about the welfare effects induced by alternative policy options and derive information about those effects from the mass media. The media might, however, secretly collude with interest groups in order to influence the public opinion. In case of voting over the level of a productivity-enhancing public bad, it is shown that a...

  9. Berbudaya Melalui Media Digital

    Directory of Open Access Journals (Sweden)

    Meilani Meilani

    2014-10-01

    Full Text Available Understanding and knowing the meaning of culture that shape the culture of a nation is the first step. Indonesia as a country that has various shades of different cultures from Sabang to Merauke, the diversity of cultural patterns is a matter of pride that should be preserved and passed on to generations of recipients so that its presence can be maintained. Do not let the culture of Indonesia is claimed by other countries simply because of ignorance and indifference to the Indonesian cultural heritage. Various means have been taken to promote the culture of the archipelago in conventional media such as magazines, books and even articles. Generations who have lived in abundance world of digital media technology is the next target of inheritance. So it would be nice if steps are taken to a great start to focus more on the spread of culture and passed it along the changing times and of course without losing the identity of the nation. 

  10. In medias res

    DEFF Research Database (Denmark)

    Foote, Jonathan

    2017-01-01

    nor does he begin the Trojan War ab ovo (with the egg) but always he hurries to the action and snatches the listener in medias res (into the middle of things)      Horace, Ars Poetica 145–147 Good epic poets do not commence their tale from the beginning—ab ovo (with the egg)—as Horace states......, but rather descend in medias res (into the middle of things), a reference to the Illiad opening already many years into the Trojan War. Perhaps this sentiment of plunging into the middle of action was felt by researchers in 1976 when, upon the walls of the San Lorenzo New Sacristy in Florence, they uncovered...... an astonishing array of mural drawings beneath centuries old plaster, recognized instantly as the possible handiwork of Michelangelo himself. Primarily related to the work at the Laurentian Library in the years 1525 and 1526, the walls of the New Sacristy apse preserve a palimpsest of hundreds of figural...

  11. FOTOGRAFI UNTUK MEDIA MASSA

    Directory of Open Access Journals (Sweden)

    Andry Prasetyo

    2016-01-01

    Full Text Available The benefits of photography as a tool for an effective and reliable communicating, are summarized in Photo journalistic . In one side, photography has the feel of reality in detail the reliable, furthermore, photography is also a more rapidly digested, knew and understood. So the response and reaction will be given to the information that there will be more quickly and precisely. Moreover with the invention of digital technology will shorten the process of delivering information to better results and faster. Through a combination of drawings and manuscripts, photographs contained in a newspaper or magazine will give us information as is appropriate. Because the image is recorded based on trust-owned, which is something that is absolutely necessar y to inform the sustainability of human life on this earth. In addition, not only, the works of photo-journalistic produced have the factual, reality and detail that is strong, but also contains the values of the beauty of high, given the work that was created by a photojournalist eye will be seen by millions of human beings throughout the world through the mass media both print and electronically. Keywords: Photography, Mass Media, Script.

  12. DIGITALIZATION AND NEW MEDIA LANDSCAPE

    Directory of Open Access Journals (Sweden)

    Tadej Praprotnik

    2016-05-01

    Full Text Available The article presents the phenomena of new communication technologies. It exposes the role of social media (Web 2.0 and sketches some global trends within the field of new media. It further outlines basic characteristics of traditional mass communication and consumption of media products, and as a counter-part presents interactive nature of a new media and the phenomena of user-generated media contents. The main focus of the article is the process of digitalization and its influence on important social system: media industry and production. Digitalization and growth of social media have challenged the news industry, so the latter has to adjust its media production to the rising power of independent publishers on social media platforms, as well as to users, which became publishers themselves, the so-called prosumers. The process of multimedia production is described through various types of inclusion promised in the technological formats. This article also highlights the transformed “intimacy” of new media cultures, which presents further evidence of new, unstable, and to some respect blurring divisions between the public and private spheres of communication. Several positive and negative consequences of digitalization on media landscape are enumerated. There are problems concerning transparency, accountability and professionalism of media production. Digital media has speed up the process of media production, journalists are faced with lack of time. Journalists as multitasking professionals are becaming the norm. The article exposes social activities manifested on social media (networks. Social networks, such as Facebook and Twitter, are becoming news platforms for spreading information and news among users. Moreover, social media has become a powerful tool for publishers and journalists, as it enables them to augment or to keep their audience. Since social networks are usually used to accomplish interpersonal rather than professional goals

  13. IMPACT OF MEDIA AND INFORMATION

    OpenAIRE

    K. Veerakumar; C. Balasanthoshkumaar

    2016-01-01

    Media is acquiring crucial importance at the present era. The Purpose of this study was to examine Social Media use among users and how it affects communication with others. The news and information’s are reaching the people faster and more efficiently. At the same time merely little fake news is also created by the media. Because, the necessary aims of the media are earning money by the way of attracting public. This study is based on scientific observations and researched on the literatu...

  14. Provenance data in social media

    CERN Document Server

    Barbier, Geoffrey; Gundecha, Pritam

    2013-01-01

    Social media shatters the barrier to communicate anytime anywhere for people of all walks of life. The publicly available, virtually free information in social media poses a new challenge to consumers who have to discern whether a piece of information published in social media is reliable. For example, it can be difficult to understand the motivations behind a statement passed from one user to another, without knowing the person who originated the message. Additionally, false information can be propagated through social media, resulting in embarrassment or irreversible damages. Provenance data

  15. Public health and media advocacy.

    Science.gov (United States)

    Dorfman, Lori; Krasnow, Ingrid Daffner

    2014-01-01

    Media advocacy blends communications, science, politics, and advocacy to advance public health goals. In this article, we explain how media advocacy supports the social justice grounding of public health while addressing public health's "wicked problems" in the context of American politics. We outline media advocacy's theoretical foundations in agenda setting and framing and describe its practical application, from the layers of strategy to storytelling, which can illuminate public health solutions for journalists, policy makers, and the general public. Finally, we describe the challenges in evaluating media advocacy campaigns.

  16. Towards fashion media for sustainability

    DEFF Research Database (Denmark)

    Skjold, Else

    2014-01-01

    Throughout the chapter, it is pointed out how fashion media traditionally fuel on unsustainable imbalances of self, in terms of affluence, gender, ethnicity, body types and age. The chapter opens with a historic outline. Here, the close alliance between media and industry is problematized, whilst...... at the same time it is highlighted how these media have produced some of the most significant imagery of modern times. Pushing the envelope of this format, Skjold suggests how fashion art magazine and user-generated style magazines might hold the key for new templates challenging existing hegemony, this way...... establishing more sustainable fashion media in the future....

  17. Social Media and Supply Chain

    Directory of Open Access Journals (Sweden)

    Sonja Markova

    2013-02-01

    Full Text Available Web 2.0, also referred to as social media, is the use of the World Wide Web to increase creativity, information sharing, and collaboration among users. Social media is driving the rethinking of many of the principles of economics. The use of social media within supply chains is lagging behind their usage for other operational functions, however supply chain management is evolving into supply chain management 2.0.The purpose of this article is to provide researches of the supply chain management a reference with the main concepts of social media: social profiles, social applications, brand outposts and communities, and the social ecosystem.

  18. Outlooks on Children and Media: Child Rights, Media Trends, Media Research, Media Literacy, Child Participation, Declarations. Children and Media Violence Yearbook, 2001.

    Science.gov (United States)

    von Feilitzen, Cecilia; Bucht, Catharina

    Focusing on media literacy, this yearbook compiles information on recent and current trends in media effects, including research on children and media, declarations related to the area, and a selection of relevant organizations and Web sites. The report first delineates children's rights as stipulated in the U.N. Convention on the Rights of the…

  19. Social Media as Collaborative Media in Workplace Learning

    Science.gov (United States)

    Thomas, Kristopher J.; Akdere, Mesut

    2013-01-01

    As a result of rapid changes in technology, much is discussed about the use of social media in branding, marketing, and in general corporate communications. The intensity with which social media tools--blogs, wikis, Twitter, instant messaging (IM) and Facebook, among others--have proliferated is staggering. Increasingly important is the role of…

  20. Public framing organizational crisis situations: social media versus news media

    NARCIS (Netherlands)

    van der Meer, T.G.L.A.; Verhoeven, P.

    2013-01-01

    This study examines framing of organizational crises by news media and the public. Due to the rapidly evolving and escalating character of crises, this study emphasizes the initial phase of a crisis, in which public social media manifestations (tweets) play a crucial role. Moreover, this study uses

  1. Media Technology Perspectives and Their Curriculum Implications for Media Education.

    Science.gov (United States)

    Lee, Alice Yuet Lin

    1996-01-01

    Develops a typology to evaluate and analyze the social and cultural impact of media technologies and to explore curriculum implications. The typology divides existing studies on communication technology into technological determinism, determined technology, and socially constructed technology. Resulting curriculum developments in media education…

  2. Trolling New Media: Violent Extremist Groups Recruiting Through Social Media

    Science.gov (United States)

    2015-12-01

    and the types of information users shared. Over 70 percent of social media users share information about music and movie preferences, 56 percent...publicize sports interests, and 37 percent recommend or discuss products they use.37 Social media is also a main source of news and politics for

  3. Teori Media-Marxist: Sebuah Pengantar

    Directory of Open Access Journals (Sweden)

    Zulfebriges Zulfebriges

    2003-06-01

    Full Text Available Teori Media-Marxist mengasumsikan media sebagai arena pertarungan ideologi berbagai kelas. Dalam perspektifnya, para profesional media menikmati ilusi otonomi dan tersosialisasikan dalam kerangka norma budaya dominan. Media dianggap memiliki kerangka interpretasi yang sesuai dengan budaya dominan. Sementara, khalayak media sendiri lebih sering menegaskan dan mengontekskan kerangka tersebut karena ketidaksiapan menghadapi sistem makna alternatif yang memungkinkan mereka menolak definisi yang ditawarkan media secara konsisten. Bertitik tolak dari asumsi ini, maka teori Media-Marxist menawarkan cara pandang baru untuk menganalisis media dengan sejumlah konsep kunci: media sebagai cara produksi, media sebagai amplifier, hegemoni ala Gramsci, sampai pada text-reading ala Stuart Hall. Kendati demikian, sejumlah hal harus dicermati dalam penerapan teori Media-Marxist pada riset-riset media. Lyle mendefinisikan sembilan kelemahan teori Media-Marxist—beberapa di antaranya bersumber dari keyakinan bahwa dinamika masyarakat digerakkan sepenuhnya oleh perjuangan kelas, dan bahwa konflik senantiasa harus diselesaikan melalui cara-cara revolusioner.

  4. Media work as public affairs: moving beyond media savvy

    DEFF Research Database (Denmark)

    Trapp, Leila; Laursen, Bo

    Much research exists which examines how politically-motivated organizations adapt their communication practices to suit the news media’s routines and values to gain media coverage and thereby exert political influence. The mediatization literature describes these adaptation processes as constantly...... evolving, with professional communicators exhibiting an ever-growing amount of media savvy. The purpose of this study is to gain up-to-date insights into current forms of media adaptation in political organizations through interviews with professional press contact staff in 52 Danish interest groups....... The interviews reveal that media work is considered an effective, though potentially risky, form of public affairs. Indeed, media work is said to damage, or even ruin, an organization’s lobbying efforts or relationships with political actors. The study’s key finding is that in order to deal with these risks...

  5. Media Massa: dalam Jerat Jaring Neoliberalisme

    OpenAIRE

    Narendra, Pitra

    2003-01-01

    Neoliberalism has allowed the increasingly globalization of mass media flourishing within the control of a few multinational corporation. Privatization of the mass media held by the neoliberals has been presented as evident for the sceptics that mass media fail to perform as the fourth estate in democratic society. Ownership of the media by private capital would destroy the media independence.

  6. Democracy, Political Perceptions, and New Media

    OpenAIRE

    Houman Sadri; Madelyn Flammia

    2014-01-01

    The participation of citizens in a democratic government is often influenced by the media, particularly new communication technologies. The differences between mass media and new media are pertinent to understanding how each works to shape our opinions and perceptions. Students need to understand the role of both traditional mass media outlets and new media in shaping public participation in our society.

  7. Mediamorphosis: Analyzing the Convergence of Digital Media ...

    African Journals Online (AJOL)

    User

    2011-04-19

    Apr 19, 2011 ... Will the emergence and development of digital media forms mean the death of the traditional media forms? ... Key Words: Mediamorphosis, Convergence, Digital Media, African. Traditional Media, Media ... has led to their wide diffusion and application, thus increasing their economic and social impact.

  8. How to be a local media celebrity.

    Science.gov (United States)

    Trent, Nancy

    2009-01-01

    Building relationships with the media in your region can turn you into a local "media darling. "As a PR-savvy doctor, there are certain techniques to get you the media attention you desire. This article will offer tips for getting local media on your side and working with media, and ways to mobilize your vendors to garner PR in your region.

  9. MEDIA EFFECTS THEORIES

    Directory of Open Access Journals (Sweden)

    Elena MAFTEI-GOLOPENȚIA

    2015-11-01

    Full Text Available The complexity of the world and the various existing points of view play sometimes the role of barriers to understanding the events that take place around us or in which we are directly involved, that we may find overwhelming sometimes. In this context, we have no choice but to find instruments that can help us find a meaning beyond ”raw” information. Frames and other media effects theories can be this instrument, that can help us understand ”the stories” about the surrounding world. Frames are useful to us because our mind can’t simply process each new situation from scratch. This paper aims mainly at analysing frames, their function, their types, their roles and the levels at which they manifest themselves. It also represents the theoretical background of a future case study about the way in which the academic world is symbolically seen by the press.

  10. Images in Social Media

    DEFF Research Database (Denmark)

    Ørnager, Susanne; Lund, Haakon

    This book focuses on methodologies, organization and communication of digital image collection research that utilize social media content. (“Image” is here understood as cultural, conventional and commercial - stock photos - representations.) The lecture offer expert views that provide different ...... fake news, image manipulation, mobile photos etc. these issues are very complex and need a publication of their own. This book should primarily be useful for students in library and information science, psychology, and computer science....... focus on the proper features of an image such as persons, object, time etc., and if a prescribed theme affects the eye movements of the observers. The results may point to renewed requirements for building image search engines. As it stands, image management already requires new algorithms and a new...

  11. Convection in porous media

    CERN Document Server

    Nield, Donald A

    1992-01-01

    This book provides a user-friendly introduction to the topic of convection in porous media The authors as- sume that the reader is familiar with the basic elements of fluid mechanics and heat transfer, but otherwise the book is self-contained The book will be useful both as a review (for reference) and as a tutorial work, suitable as a textbook in a graduate course or seminar The book brings into perspective the voluminous research that has been performed during the last two decades The field has recently exploded because of worldwide concern with issues such as energy self-sufficiency and pollution of the environment Areas of application include the insulation of buildings and equipment, energy storage and recovery, geothermal reservoirs, nuclear waste disposal, chemical reactor engineering, and the storage of heat-generating materials such as grain and coal Geophysical applications range from the flow of groundwater around hot intrusions to the stability of snow against avalanches

  12. [Isotretinoin, depression and medias].

    Science.gov (United States)

    Wolkenstein, P

    2010-11-01

    Acne is a frequent disease with a strong impact upon quality of life. The most effective treatment of severe acne is isotretinoin. Cases of suicid have been reported during isotretinoin treatments in adolescents and were mediatised. Now a day, the link between isotretinoin intake and psychiatric troubles is not established at populational level. The pressure of public and medias led the French Drug Agency to send a letter to health professionals to summarize the scientific question. An explanative video is on line on the website of the French Society of Dermatology www.dermato-info.fr. This video summarizes the state of the art concerning the context of isotretinoin for public, dermatologists and other physicians To summarize isotretinoin is the drug for severe acne in case of failure of first line classical treatment. Dermatologists must stay the first line prescribers reminding that adolescence is a fragile period. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

  13. Social Media Mourning.

    Science.gov (United States)

    Moore, Jensen; Magee, Sara; Gamreklidze, Ellada; Kowalewski, Jennifer

    2017-01-01

    This article uses grounded theory methodology to analyze in-depth interviews conducted with mourners who used social networking sites during bereavement. The social media mourning (SMM) model outlines how social networking sites are used to grieve using one or more of the following: (a) one-way communication, (b) two-way communication, and (c) immortality communication. The model indicates causal conditions of SMM: (a) sharing information with family or friends and (sometimes) beginning a dialog, (b) discussing death with others mourning, (c) discussing death with a broader mourning community, and (d) commemorating and continuing connection to the deceased. The article includes actions and consequences associated with SMM and suggests several ways in which SMM changes or influences the bereavement process.

  14. Convection in Porous Media

    CERN Document Server

    Nield, Donald A

    2013-01-01

    Convection in Porous Media, 4th Edition, provides a user-friendly introduction to the subject, covering a wide range of topics, such as fibrous insulation, geological strata, and catalytic reactors. The presentation is self-contained, requiring only routine mathematics and the basic elements of fluid mechanics and heat transfer. The book will be of use not only to researchers and practicing engineers as a review and reference, but also to graduate students and others entering the field. The new edition features approximately 1,750 new references and covers current research in nanofluids, cellular porous materials, strong heterogeneity, pulsating flow, and more. Recognized as the standard reference in the field Includes a comprehensive, 250-page reference list Cited over 2300 times to date in its various editions Serves as an introduction for those entering the field and as a comprehensive reference for experienced researchers Features new sections on nanofluids, carbon dioxide sequestration, and applications...

  15. Filtration in Porous Media

    DEFF Research Database (Denmark)

    Yuan, Hao; Shapiro, Alexander

    There is a considerable and ongoing effort aimed at understanding the transport and the deposition of suspended particles in porous media, especially non-Fickian transport and non-exponential deposition of particles. In this work, the influential parameters in filtration models are studied...... to understand their effects on the non-Fickian transport and the non-exponential deposition. The filtration models are validated by the comparisons between the modelling results and the experimental data.The elliptic equation with distributed filtration coefficients may be applied to model non-Fickian transport...... and hyperexponential deposition. The filtration model accounting for the migration of surface associated particles may be applied for non-monotonic deposition....

  16. The Mass Media

    DEFF Research Database (Denmark)

    Valentini, Chiara; Laursen, Bo

    2012-01-01

    This chapter deals with the EU institutions’ external communication and how it relates to the European public sphere(s). We argue that one of the preconditions for establishing a well-functioning European public sphere is that the EU institutions’ decision-making and political debates around...... policies and issues are organised in such a way that the European citizens 1) are informed of the actions of European political leaders and top executives in ways that appeal to a wide range of publics, and 2) are encouraged to discuss and enter in a dialogue about these issues in appropriate communicative...... spaces. We postulate that citizens’ levels of awareness and knowledge of EU matters depend on the EU institutions’ ability to reach European citizens directly or indirectly through a wide range of channels, including the mass media. Citizens’ participation in political debates, however, requires more...

  17. Crossing the Media

    DEFF Research Database (Denmark)

    Tamke, Martin

    2005-01-01

    An open-ended, diversified and critical approach of architectural design, using different form of ideas representation might offer best chances to gain new spatial solutions. Today’s most forward architects and designers are aware of this and make full use of physical and digital media during...... techniques, analogue and digital, were used in an experimental way and their interaction and adaptability in the field of architecture was analyzed. The work examines the possibility of a consistent integration of digital and physical representation in a design process and the individual benefits of each...... and the emerging questions and impulses to architect future work and theory. The discovered limitations and consequences of interfaces between the analogue and digital realm of design and their creative chances will be revealed. We share results which we think may be helpful to others, and we highlight areas where...

  18. Demography and the Mass Media.

    Science.gov (United States)

    The purpose of the paper is to delineate the relationship between the mass communications media and the science of demography . It begins with a...discussion of demography , its history, methodology and limitations, followed by a review of communications theory as it applies to the mass media. The

  19. Media and Young Children's Learning

    Science.gov (United States)

    Kirkorian, Heather L.; Wartella, Ellen A.; Anderson, Daniel R.

    2008-01-01

    Electronic media, particularly television, have long been criticized for their potential impact on children. One area for concern is how early media exposure influences cognitive development and academic achievement. Heather Kirkorian, Ellen Wartella, and Daniel Anderson summarize the relevant research and provide suggestions for maximizing the…

  20. Algorithms and Public Service Media

    DEFF Research Database (Denmark)

    Sørensen, Jannick Kirk; Hutchinson, Jonathon

    2018-01-01

    When Public Service Media (PSM) organisations introduce algorithmic recommender systems to suggest media content to users, fundamental values of PSM are challenged. Beyond being confronted with ubiquitous computer ethics problems of causality and transparency, also the identity of PSM as curator...