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Sample records for vti media poroelasticity

  1. Physical modelling and the poroelastic model with application to fluid detection in a VTI medium

    International Nuclear Information System (INIS)

    Li, Shengjie

    2013-01-01

    In this paper, both poroelasticity theory and pre-stack inversions have been combined to generate a flexible way to derive an effective fluid factor, which is then used to identify the presence of the hydrocarbon in weakly anisotropic VTI reservoirs. The effective fluid factor has been derived by using an approximate fluid substitution equation for anisotropic VTI media. The approximate equation provides a means of performing fluid substitution for elastic moduli along the vertical symmetry axis of a VTI medium with fewer elastic moduli. The effective fluid factor can be used to analyse the sensitivity of seismic attributes to fluid content. In order to examine the effectiveness of the effective fluid factor, an anisotropic physical model has been constructed. The rock properties of artificial sandstone used as a reservoir building material are properly selected by using an empirical model and Gassmann's equation. An effort is made to ensure the physical modelling data represent the 'true’ response of different fluid-filled sands. The fluid detection method is then applied to interpret the inverted seismic impedance obtained from physical modelling seismic data with some known gas-sands and wet-sands. The results shows that the interpretive resolution of seismic fluid detection has been dramatically improved by using the effective fluid factor. In addition, more information on lateral changes in fluid content can be distinguished. This study has demonstrated the potential of this method in detecting different fluid content in weakly anisotropic VTI reservoirs. (paper)

  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.; Ursin, Bjø rn; Stoffa, Paul L.

    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. An acoustic eikonal equation for attenuating VTI media

    KAUST Repository

    Hao, Qi; Alkhalifah, Tariq Ali

    2016-01-01

    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

  5. 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.

  6. 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.

  7. 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.

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

    KAUST Repository

    Pestana, Reynam C; Ursin, Bjø rn; Stoffa, Paul L

    2012-01-01

    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.

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

    KAUST Repository

    Djebbi, Ramzi; Alkhalifah, Tariq Ali

    2017-01-01

    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

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

    KAUST Repository

    Kamath, Nishant; Tsvankin, Ilya

    2014-01-01

    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.

  11. 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.

  12. 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.

  13. 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.

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

    KAUST Repository

    Hao, Q.; Alkhalifah, Tariq Ali

    2017-01-01

    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.

  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. Analysis of Thomsen parameters for finely layered VTI media

    International Nuclear Information System (INIS)

    Berryman, J.G.; Berge, P.A.

    1997-01-01

    The range of Thomsen's anisotropy parameters ε and δ for vertical transversely isotropic (VTI) media when the anisotropy is due to fine layering of isotropic elas-tic materials is considered. We show that ε lies in the range -3/8 ≤ ε ≤ 1/2 v p 2 > p-2 >-1 for finely layered media having constant density; smaller positive and all negative values of ε occur for media with large fluctuations in the Lamacute e parameter λ We show that sign(δ) = sign ( p -2 > - s -2 > s 2 /v p 2 >) for constant density media, so δ can be either positive or negative. Among all theoretically possible random media, posi-tive and negative δ are equally likely in finely layered media limited to two types of constituent layers. Lay-ered media having large fluctuations in Lamacute e λ are the ones most likely to have positive δ. Since Gassmann's results for fluid-saturated porous media show that the effects of fluids influence only the λ Lamacute e constant, not the shear modulus μ, these results suggest that positive δ occurring together with positive but small ε may be indicative of changing fluid content in layered earth

  17. An effective anisotropic poroelastic model for elastic wave propagation in finely layered media

    NARCIS (Netherlands)

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

    2016-01-01

    Mesoscopic-scale heterogeneities in porous media cause attenuation and dispersion at seismic frequencies. Effective models are often used to account for this. We have developed a new effective poroelastic model for finely layered media, and we evaluated its impact focusing on the angledependent

  18. Mechanics of layered anisotropic poroelastic media with applications to effective stress for fluid permeability

    Energy Technology Data Exchange (ETDEWEB)

    Berryman, J.G.

    2010-06-01

    The mechanics of vertically layered porous media has some similarities to and some differences from the more typical layered analysis for purely elastic media. Assuming welded solid contact at the solid-solid interfaces implies the usual continuity conditions, which are continuity of the vertical (layering direction) stress components and the horizontal strain components. These conditions are valid for both elastic and poroelastic media. Differences arise through the conditions for the pore pressure and the increment of fluid content in the context of fluid-saturated porous media. The two distinct conditions most often considered between any pair of contiguous layers are: (1) an undrained fluid condition at the interface, meaning that the increment of fluid content is zero (i.e., {delta}{zeta} = 0), or (2) fluid pressure continuity at the interface, implying that the change in fluid pressure is zero across the interface (i.e., {delta}p{sub f} = 0). Depending on the types of measurements being made on the system and the pertinent boundary conditions for these measurements, either (or neither) of these two conditions might be directly pertinent. But these conditions are sufficient nevertheless to be used as thought experiments to determine the expected values of all the poroelastic coefficients. For quasi-static mechanical changes over long time periods, we expect drained conditions to hold, so the pressure must then be continuous. For high frequency wave propagation, the pore-fluid typically acts as if it were undrained (or very nearly so), with vanishing of the fluid increment at the boundaries being appropriate. Poroelastic analysis of both these end-member cases is discussed, and the general equations for a variety of applications to heterogeneous porous media are developed. In particular, effective stress for the fluid permeability of such poroelastic systems is considered; fluid permeabilities characteristic of granular media or tubular pore shapes are treated

  19. Microstructural effects on the overall poroelastic properties of saturated porous media

    International Nuclear Information System (INIS)

    Bouhlel, M; Jamei, M; Geindreau, C

    2010-01-01

    At the macroscopic scale, the quasi-static deformation of an elastic porous medium saturated by an incompressible Newtonian fluid is described by the well-known Biot's model, which involves four effective parameters. In this work, the three effective poroelastic properties and the permeability of two periodic microstructures of saturated cohesive granular media, i.e. simple cubic (SC) and body-centered cubic (BCC) arrays of overlapping spheres, are computed by solving, over the representative elementary volume, boundary-value problems arising from the homogenization process. The influence of microstructure properties, i.e. solid volume fraction, arrangement of spheres, number of contacts as well as the intrinsic properties of the solid phase on the overall properties, is highlighted. Numerical results are then compared with rigorous bounds, self-consistent estimations, exact expansions and experimental results on ceramics and metals available in the literature. Finally, the capability of the obtained results on such periodic microstructures to describe the poroelastic properties of real porous media is discussed

  20. 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.

  1. 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.

  2. One-dimensional energy flow model for poroelastic material

    International Nuclear Information System (INIS)

    Kim, Jung Soo; Kang, Yeon June

    2009-01-01

    This paper presents a one-dimensional energy flow model to investigate the energy behavior for poroelastic media coupled with acoustical media. The proposed energy flow model is expressed by an independent energy governing equation that is classified into each wave component propagating in poroelastic media. The energy governing equation is derived using the General Energetic Method (GEM). To facilitate a comparison with the classical solution based on the conventional displacement-base formulation, approximate solutions of energy density and intensity are obtained. Furthermore, the limitations and usability of the proposed energy flow model for poroelastic media are described.

  3. 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.

  4. Analysis of RTM extended images for VTI media

    KAUST Repository

    Li, Vladimir; Tsvankin, Ilya; Alkhalifah, Tariq Ali

    2016-01-01

    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.

  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. 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

  7. Poroelastic Response of Orthotropic Fractured Porous Media

    Energy Technology Data Exchange (ETDEWEB)

    Berryman, James G. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division

    2011-12-16

    In this paper, an algorithm is presented for inverting either laboratory or field poroelastic data for all the drained constants of an anisotropic (specifically orthotropic) fractured poroelastic system. While fractures normally weaken the system by increasing the mechanical compliance, any liquids present in these fractures are expected to increase the stiffness somewhat, thus negating to some extent the mechanical weakening influence of the fractures themselves. The analysis presented in this article quantifies these effects and shows that the key physical variable needed to account for the pore-fluid effects is a factor of (1 - B), where B is Skempton’s second coefficient and satisfies 0 ≤ B < 1. This scalar factor uniformly reduces the increase in compliance due to the presence of communicating fractures, thereby stiffening the fractured composite medium by a predictable amount. One further aim of the discussion is to determine the number of the poroelastic constants that needs to be known by other means to determine the rest from remote measurements, such as seismic wave propagation data in the field. Quantitative examples arising in the analysis show that, if the fracture aspect ratio af ≃ 0.1 and the pore fluid is liquid water, then for several cases considered, Skempton’s B ≃ 0.9, and so the stiffening effect of the pore-liquid reduces the change in compliance due to the fractures by a factor 1-B ≃ 0.1, in these examples. The results do, however, depend on the actual moduli of the unfractured elastic material, as well as on the pore-liquid bulk modulus, so these quantitative predictions are just examples, and should not be treated as universal results. Attention is also given to two previously unremarked poroelastic identities, both being useful variants of Gassmann’s equations for homogeneous—but anisotropic—poroelasticity. Relationships to Skempton’s analysis of saturated soils are also noted. Finally, the article concludes

  8. Optimal implicit 2-D finite differences to model wave propagation in poroelastic media

    Science.gov (United States)

    Itzá, Reymundo; Iturrarán-Viveros, Ursula; Parra, Jorge O.

    2016-08-01

    Numerical modeling of seismic waves in heterogeneous porous reservoir rocks is an important tool for the interpretation of seismic surveys in reservoir engineering. We apply globally optimal implicit staggered-grid finite differences (FD) to model 2-D wave propagation in heterogeneous poroelastic media at a low-frequency range (differentiation involves solving tridiagonal linear systems of equations through Thomas' algorithm.

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

    KAUST Repository

    Kamath, Nishant; Tsvankin, Ilya; Diaz, Esteban

    2016-01-01

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Berryman, J.G.

    2009-11-20

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

  11. 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.

  12. Seismic wave propagation in heterogeneous multiphasic media: numerical modelling, sensibility and inversion of poro-elastic parameters

    International Nuclear Information System (INIS)

    Dupuy, B.

    2011-11-01

    Seismic wave propagation in multiphasic porous media have various environmental (natural risks, geotechnics, groundwater pollutions...) and resources (aquifers, oil and gas, CO 2 storage...) issues. When seismic waves are crossing a given material, they are distorted and thus contain information on fluid and solid phases. This work focuses on the characteristics of seismic waves propagating in multiphasic media, from the physical complex description to the parameter characterisation by inversion, including 2D numerical modelling of the wave propagation. The first part consists in the description of the physics of multiphasic media (each phase and their interactions), using several up-scaling methods, in order to obtain an equivalent mesoscale medium defined by seven parameters. Thus, in simple porosity saturated media and in complex media (double porosity, patchy saturation, visco-poro-elasticity), I can compute seismic wave propagation without any approximation. Indeed, I use a frequency-space domain for the numerical method, which allows to consider all the frequency dependent terms. The spatial discretization employs a discontinuous finite elements method (discontinuous Galerkin), which allows to take into account complex interfaces.The computation of the seismic attributes (velocities and attenuations) of complex porous media shows strong variations in respect with the frequency. Waveforms, computed without approximation, are strongly different if we take into account the full description of the medium or an homogenisation by averages. The last part of this work deals with the poro-elastic parameters characterisation by inversion. For this, I develop a two-steps method: the first one consists in a classical inversion (tomography, full waveform inversion) of seismograms data to obtain macro-scale parameters (seismic attributes). The second step allows to recover, from the macro-scale parameters, the poro-elastic micro-scale properties. This down-scaling step

  13. 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.

  14. Inversion gradients for acoustic VTI wavefield tomography

    KAUST Repository

    Li, Vladimir; Wang, Hui; Tsvankin, Ilya; Dí az, Esteban; Alkhalifah, Tariq Ali

    2017-01-01

    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.

  15. 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.

  16. 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.

  17. 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.

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

    KAUST Repository

    Kamath, Nishant; Tsvankin, Ilya

    2014-01-01

    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.

  19. Multiscale optimization of saturated poroelastic actuators

    DEFF Research Database (Denmark)

    Andreasen, Casper Schousboe; Sigmund, Ole

    A multiscale method for optimizing the material micro structure in a macroscopically heterogeneous saturated poroelastic media with respect to macro properties is presented. The method is based on topology optimization using the homogenization technique, here applied to the optimization of a bi...

  20. 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.

  1. 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

    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......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...... 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...

  2. Reflection moveout approximation for a converted P-SV wave in a moderately anisotropic homogeneous VTI layer

    Czech Academy of Sciences Publication Activity Database

    Farra, V.; Pšenčík, Ivan

    2017-01-01

    Roč. 27 (2017), s. 51-58 ISSN 2336-3827 R&D Projects: GA ČR(CZ) GA16-05237S Institutional support: RVO:67985530 Keywords : VTI media Subject RIV: DC - Siesmology, Volcanology, Earth Structure OBOR OECD: Volcanology

  3. Approximate reflection coefficients for a thin VTI layer

    KAUST Repository

    Hao, Qi; Stovas, Alexey

    2017-01-01

    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

  4. 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.

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

    KAUST Repository

    Feng, Shihang; Schuster, Gerard T.

    2017-01-01

    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.

  6. 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.

  7. 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...... by topology optimization in order to optimize the performance of a shock absorber and test the pressure loading capabilities and optimization of an internally pressurized lid. © 2013 Published by Elsevier B.V....

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

    KAUST Repository

    Wheeler, Mary; Xue, Guangri; Yotov, Ivan

    2013-01-01

    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

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. A combined application of boundary-element and Runge-Kutta methods in three-dimensional elasticity and poroelasticity

    Directory of Open Access Journals (Sweden)

    Igumnov Leonid

    2015-01-01

    Full Text Available The report presents the development of the time-boundary element methodology and a description of the related software based on a stepped method of numerical inversion of the integral Laplace transform in combination with a family of Runge-Kutta methods for analyzing 3-D mixed initial boundary-value problems of the dynamics of inhomogeneous elastic and poro-elastic bodies. The results of the numerical investigation are presented. The investigation methodology is based on direct-approach boundary integral equations of 3-D isotropic linear theories of elasticity and poroelasticity in Laplace transforms. Poroelastic media are described using Biot models with four and five base functions. With the help of the boundary-element method, solutions in time are obtained, using the stepped method of numerically inverting Laplace transform on the nodes of Runge-Kutta methods. The boundary-element method is used in combination with the collocation method, local element-by-element approximation based on the matched interpolation model. The results of analyzing wave problems of the effect of a non-stationary force on elastic and poroelastic finite bodies, a poroelastic half-space (also with a fictitious boundary and a layered half-space weakened by a cavity, and a half-space with a trench are presented. Excitation of a slow wave in a poroelastic medium is studied, using the stepped BEM-scheme on the nodes of Runge-Kutta methods.

  14. Mapping moveout approximations in TI media

    KAUST Repository

    Stovas, Alexey; Alkhalifah, Tariq Ali

    2013-01-01

    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.

  15. 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.

  16. 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

  17. 2.5-D poroelastic wave modelling in double porosity media

    Science.gov (United States)

    Liu, Xu; Greenhalgh, Stewart; Wang, Yanghua

    2011-09-01

    To approximate seismic wave propagation in double porosity media, the 2.5-D governing equations of poroelastic waves are developed and numerically solved. The equations are obtained by taking a Fourier transform in the strike or medium-invariant direction over all of the field quantities in the 3-D governing equations. The new memory variables from the Zener model are suggested as a way to represent the sum of the convolution integrals for both the solid particle velocity and the macroscopic fluid flux in the governing equations. By application of the memory equations, the field quantities at every time step need not be stored. However, this approximation allows just two Zener relaxation times to represent the very complex double porosity and dual permeability attenuation mechanism, and thus reduce the difficulty. The 2.5-D governing equations are numerically solved by a time-splitting method for the non-stiff parts and an explicit fourth-order Runge-Kutta method for the time integration and a Fourier pseudospectral staggered-grid for handling the spatial derivative terms. The 2.5-D solution has the advantage of producing a 3-D wavefield (point source) for a 2-D model but is much more computationally efficient than the full 3-D solution. As an illustrative example, we firstly show the computed 2.5-D wavefields in a homogeneous single porosity model for which we reformulated an analytic solution. Results for a two-layer, water-saturated double porosity model and a laterally heterogeneous double porosity structure are also presented.

  18. 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.

  19. Dispersion in poroelastic systems

    International Nuclear Information System (INIS)

    Berryman, James G.; Wang, Herbert F.

    2001-01-01

    We address one key source of the known discrepancies between theory and experiment in poroelasticity, i.e., the fact that Gassmann's equations for the bulk and shear moduli predict that the shear modulus is independent of the saturating fluid properties, whereas it is observed on the contrary that at high enough frequencies the shear modulus can in fact depend on the fluid's elastic properties in many porous materials. One clue to understanding this behavior comes from effective medium theory, which shows that the shear modulus does depend on the fluid properties in many circumstances. In comparison to values predicted by effective medium theory, Gassmann's equations predict different, smaller values for both the effective bulk and shear moduli of porous media. Sorting through these apparent (but not actual) disagreements among theory and theory, and theory and experiment is the main thrust of the paper

  20. Gradient computation for VTI acoustic wavefield tomography

    KAUST Repository

    Li, Vladimir; Wang, Hui; Tsvankin, Ilya; Diaz, Esteban; Alkhalifah, Tariq Ali

    2016-01-01

    -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

  1. Well-Posedness of a fully coupled thermo-chemo-poroelastic system with applications to petroleum rock mechanics

    Directory of Open Access Journals (Sweden)

    Tetyana Malysheva

    2017-05-01

    Full Text Available We consider a system of fully coupled parabolic and elliptic equations constituting the general model of chemical thermo-poroelasticity for a fluid-saturated porous media. The main result of this paper is the developed well-posedness theory for the corresponding initial-boundary problem arising from petroleum rock mechanics applications. Using the proposed pseudo-decoupling method, we establish, subject to some natural assumptions imposed on matrices of diffusion coefficients, the existence, uniqueness, and continuous dependence on initial and boundary data of a weak solution to the problem. Numerical experiments confirm the applicability of the obtained well-posedness results for thermo-chemo-poroelastic models with real-data parameters.

  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 ...

  3. 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.

  4. 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.

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

    International Nuclear Information System (INIS)

    Zhang, Feng-Juan; Han, Ruo-Ling; Zhao, Xin-Ming

    2014-01-01

    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

  6. Grotrian diagrams for highly ionized titanium Ti V-Ti XXII

    International Nuclear Information System (INIS)

    Mori, Kazuo

    1982-06-01

    Grotrian diagrams of Ti V-Ti XXII have been prepared. Data of wavelengths, energy levels, oscillator strengths and transition probabilities are updated for diagnostics of high temperature plasmas, and tabulated with references. (author)

  7. Efficient Wavefield Extrapolation In Anisotropic Media

    KAUST Repository

    Alkhalifah, Tariq; Ma, Xuxin; Waheed, Umair bin; Zuberi, Mohammad Akbar Hosain

    2014-01-01

    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.

  8. 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.

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

    African Journals Online (AJOL)

    DR OKE

    vanished, the considered problem reduces to the problem of radial vibrations of fluid-filled poroelastic circular cylindrical shell. (2). When the .... the volume change of the solid to that of liquid. ..... When the outer fluid density is zero, that is, ρof = 0 then the poroelastic cylindrical shell immersed in an acoustic medium will.

  10. Dynamics of poroelastic foams

    Science.gov (United States)

    Forterre, Yoel; Sobac, Benjamin

    2010-11-01

    Soft poroelastic structures are widespread in biological tissues such as cartilaginous joints in bones, blood-filled placentae or plant organs. Here we investigate the dynamics of open elastic foams immersed in viscous fluids, as model soft poroelastic materials. The experiment consists in slowly compacting blocs of polyurethane solid foam embedded in silicon oil-tanks and studying their relaxation to equilibrium when the confining stress is suddenly released. Measurements of the local fluid pressure and foam velocity field are compared with a simple two-phase flow approach. For small initial compactions, the results show quantitative agreement with the classical diffusion theory of soil consolidation (Terzaghi, Biot). On the other hand, for large initial compactions, the dynamics exhibits long relaxation times and decompaction fronts, which are mainly controlled by the highly non-linear mechanical response of the foam. The analogy between this process and the evaporation of a polymer melt close to the glass transition will be briefly discussed.

  11. 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.

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

    KAUST Repository

    Djebbi, Ramzi; Alkhalifah, Tariq Ali

    2013-01-01

    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.

  13. Normal Mode Analysis to a Poroelastic Half-Space Problem under Generalized Thermoelasticity

    Directory of Open Access Journals (Sweden)

    Chunbao Xiong

    Full Text Available Abstract The thermo-hydro-mechanical problems associated with a poroelastic half-space soil medium with variable properties under generalized thermoelasticity theory were investigated in this study. By remaining faithful to Biot’s theory of dynamic poroelasticity, we idealized the foundation material as a uniform, fully saturated, poroelastic half-space medium. We first subjected this medium to time harmonic loads consisting of normal or thermal loads, then investigated the differences between the coupled thermohydro-mechanical dynamic models and the thermo-elastic dynamic models. We used normal mode analysis to solve the resulting non-dimensional coupled equations, then investigated the effects that non-dimensional vertical displacement, excess pore water pressure, vertical stress, and temperature distribution exerted on the poroelastic half-space medium and represented them graphically.

  14. Fluid Effects on Shear Waves in Finely Layered Porous Media

    International Nuclear Information System (INIS)

    Berryman, J G

    2004-01-01

    Although there are five effective shear moduli for any layered VTI medium, one and only one effective shear modulus for the layered system contains all the dependence of pore fluids on the elastic or poroelastic constants that can be observed in vertically polarized shear waves. Pore fluids can increase the magnitude the shear energy stored by this modulus by a term that ranges from the smallest to the largest shear moduli of the VTI system. But, since there are five shear moduli in play, the increase in shear energy overall is reduced by a factor of about 5 in general. We can therefore give definite bounds on the maximum increase of shear modulus, being about 20% of the permitted range, when gas is fully replaced by liquid. An attendant increase of density (depending on porosity and fluid density) by approximately 5 to 10% partially offsets the effect of this shear modulus increase. Thus, an increase of shear wave speed on the order of 5 to 10% is shown to be possible when circumstances are favorable - i.e., when the shear modulus fluctuations are large (resulting in strong anisotropy), and the medium behaves in an undrained fashion due to fluid trapping. At frequencies higher than seismic (such as sonic and ultrasonic waves for well-logging or laboratory experiments), short response times also produce the requisite undrained behavior and, therefore, fluids also affect shear waves at high frequencies by increasing rigidity

  15. Analysis of RTM extended images for VTI media

    KAUST Repository

    Li, Vladimir; Tsvankin, Ilya; Alkhalifah, Tariq Ali

    2015-01-01

    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.

  16. 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.

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

    KAUST Repository

    Li, Vladimir; Tsvankin, Ilya; Guitton, Antoine; Alkhalifah, Tariq Ali

    2017-01-01

    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.

  18. Multi-parameter Full-waveform Inversion for Acoustic VTI Medium with Surface Seismic Data

    Science.gov (United States)

    Cheng, X.; Jiao, K.; Sun, D.; Huang, W.; Vigh, D.

    2013-12-01

    Full-waveform Inversion (FWI) attracts wide attention recently in oil and gas industry as a new promising tool for high resolution subsurface velocity model building. While the traditional common image point gather based tomography method aims to focus post-migrated data in depth domain, FWI aims to directly fit the observed seismic waveform in either time or frequency domain. The inversion is performed iteratively by updating the velocity fields to reduce the difference between the observed and the simulated data. It has been shown the inversion is very sensitive to the starting velocity fields, and data with long offsets and low frequencies is crucial for the success of FWI to overcome this sensitivity. Considering the importance of data with long offsets and low frequencies, in most geologic environment, anisotropy is an unavoidable topic for FWI especially at long offsets, since anisotropy tends to have more pronounced effects on waves traveled for a great distance. In VTI medium, this means more horizontal velocity will be registered in middle-to-long offset data, while more vertical velocity will be registered in near-to-middle offset data. Up to date, most of real world applications of FWI still remain in isotropic medium, and only a few studies have been shown to account for anisotropy. And most of those studies only account for anisotropy in waveform simulation, but not invert for those anisotropy fields. Multi-parameter inversion for anisotropy fields, even in VTI medium, remains as a hot topic in the field. In this study, we develop a strategy for multi-parameter FWI for acoustic VTI medium with surface seismic data. Because surface seismic data is insensitivity to the delta fields, we decide to hold the delta fields unchanged during our inversion, and invert only for vertical velocity and epsilon fields. Through parameterization analysis and synthetic tests, we find that it is more feasible to invert for the parameterization as vertical and horizontal

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

    KAUST Repository

    Hao, Qi; Alkhalifah, Tariq Ali

    2016-01-01

    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

  20. Guided Circumferential Waves in Layered Poroelastic Cylinders

    Directory of Open Access Journals (Sweden)

    Shah S.A.

    2016-12-01

    Full Text Available The present paper investigates the propagation of time harmonic circumferential waves in a two-dimensional hollow poroelastic cylinder with an inner shaft (shaft-bearing assembly. The hollow poroelastic cylinder and inner shaft are assumed to be infinite in axial direction. The outer surface of the cylinder is stress free and at the interface, between the inner shaft and the outer cylinder, it is assumed to be free sliding and the interfacial shear stresses are zero, also the normal stress and radial displacements are continuous. The frequency equation of guided circumferential waves for a permeable and an impermeable surface is obtained. When the angular wave number vanish the frequency equation of guided circumferential waves for a permeable and an impermeable surface degenerates and the dilatational and shear waves are uncoupled. Shear waves are independent of the nature of surface. The frequency equation of a permeable and an impermeable surface for bore-piston assembly is obtained as a particular case of the model under consideration when the outer radius of the hollow poroelastic cylinder tends to infinity. Results of previous studies are obtained as a particular case of the present study. Nondimensional frequency as a function of wave number is presented graphically for two types of models and discussed. Numerical results show that, in general, the first modes are linear for permeable and impermeable surfaces and the frequency of a permeable surface is more than that of an impermeable surface.

  1. 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...

  2. Simultaneous measurements of transport and poroelastic properties of rocks.

    Science.gov (United States)

    Hasanov, Azar K; Prasad, Manika; Batzle, Michael L

    2017-12-01

    A novel laboratory apparatus has been developed for simultaneous measurements of transport and poroelastic rock properties. These transport and poroelastic properties at reservoir pressure and temperature conditions are required inputs for various geoscience applications, such as reservoir simulation, basin modeling, or modeling of pore pressure generation. Traditionally, the transport and poroelastic properties are measured separately using, for example, the oscillating pore pressure method to measure hydraulic transport properties, static strain measurements for elastic properties, and pore volumometry for storage capacity. In addition to time, the separate set of measurements require either aliquot cores or subjecting the same core to multiple pressure tests. We modified the oscillating pore pressure method to build an experimental setup, capable of measuring permeability, storage capacity, and pseudo-bulk modulus of rocks simultaneously. We present here the test method, calibration measurements (capillary tube), and sample measurements (sandstone) of permeability and storage capacity at reservoir conditions. We establish that hydraulically measured storage capacities were overestimated by an order of magnitude when compared to elastically derived ones. Our concurrent measurement of elastic properties during the hydraulic experiment provides an independent constraint on storage capacity.

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

    KAUST Repository

    Guitton, Antoine; Alkhalifah, Tariq Ali

    2017-01-01

    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.

  4. 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.

  5. Sound transmission through triple-panel structures lined with poroelastic materials

    Science.gov (United States)

    Liu, Yu

    2015-03-01

    In this paper, previous theories on the prediction of sound transmission loss for a double-panel structure lined with poroelastic materials are extended to address the problem of a triple-panel structure. Six typical configurations are considered for a triple-panel structure based on the method of coupling the porous layers to the facing panels which determines critically the sound insulation performance of the system. The transfer matrix method is employed to solve the system by applying appropriate types of boundary conditions for these configurations. The transmission loss of the triple-panel structures in a diffuse sound field is calculated as a function of frequency and compared with that of corresponding double-panel structures. Generally, the triple-panel structure with poroelastic linings has superior acoustic performance to the double-panel counterpart, remarkably in the mid-high frequency range and possibly at low frequencies, by selecting appropriate configurations in which those with two air gaps in the structure exhibit the best overall performance over the entire frequency range. The poroelastic lining significantly lowers the cut-on frequency above which the triple-panel structure exhibits noticeably higher transmission loss. Compared with a double-panel structure, the wider range of system parameters for a triple-panel structure due to the additional partition provides more design space for tuning the sound insulation performance. Despite the increased structural complexity, the triple-panel structure lined with poroelastic materials has the obvious advantages in sound transmission loss while without the penalties in weight and volume, and is hence a promising replacement for the widely used double-panel sandwich structure.

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

    Energy Technology Data Exchange (ETDEWEB)

    Adamiec, J, E-mail: janusz.adamiec@polsl.pl [Department of Materials Science, Silesian University of Technology, Krasinskiego 8, 40-019 Katowice (Poland)

    2011-05-15

    Bainitic steel 7CrMoVTiB10-10 is one the newest steels for waterwalls of modern industrial boilers. 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. 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.

  7. Microstructure and Room-Temperature Mechanical Properties of FeCrMoVTi x High-Entropy Alloys

    Science.gov (United States)

    Guo, Jun; Huang, Xuefei; Huang, Weigang

    2017-07-01

    FeCrMoVTi x ( x values represent the molar ratio, where x = 0, 0.5, 1.0, 1.5, and 2.0) high-entropy alloys were prepared by a vacuum arc melting method. The effects of Ti element on the microstructure and room-temperature mechanical properties of the as-cast FeCrMoVTi x alloys were investigated. The results show that the prepared alloys exhibited typical dendritic microstructure and the size of the microstructure became fine with increasing Ti content. The FeCrMoV alloy exhibited a single body-centered cubic structure (BCC1) and the alloys prepared with Ti element exhibited BCC1 + BCC2 mixed structure. The new BCC2 phase is considered as (Fe, Ti)-rich phase and was distributed in the dendrite region. With the increase of Ti content, the volume fraction of the BCC2 phase increased and its shape changed from a long strip to a network. For the FeCrMoV alloy, the fracture strength, plastic strain, and hardness reached as high as 2231 MPa, 28.2%, and 720 HV, respectively. The maximum hardness of 887 HV was obtained in the FeCrMoVTi alloy. However, the fracture strength, yield stress, and plastic strain of the alloys decreased continuously as Ti content increased. In the room-temperature compressive test, the alloys showed typical brittle fracture characteristics.

  8. Large poroelastic deformation of a soft material

    Science.gov (United States)

    MacMinn, Christopher W.; Dufresne, Eric R.; Wettlaufer, John S.

    2014-11-01

    Flow through a porous material will drive mechanical deformation when the fluid pressure becomes comparable to the stiffness of the solid skeleton. This has applications ranging from hydraulic fracture for recovery of shale gas, where fluid is injected at high pressure, to the mechanics of biological cells and tissues, where the solid skeleton is very soft. The traditional linear theory of poroelasticity captures this fluid-solid coupling by combining Darcy's law with linear elasticity. However, linear elasticity is only volume-conservative to first order in the strain, which can become problematic when damage, plasticity, or extreme softness lead to large deformations. Here, we compare the predictions of linear poroelasticity with those of a large-deformation framework in the context of two model problems. We show that errors in volume conservation are compounded and amplified by coupling with the fluid flow, and can become important even when the deformation is small. We also illustrate these results with a laboratory experiment.

  9. Sufficient conditions for Hadamard well-posedness of a coupled thermo-chemo-poroelastic system

    Directory of Open Access Journals (Sweden)

    Tetyana Malysheva

    2016-01-01

    Full Text Available This article addresses the well-posedness of a coupled parabolic-elliptic system modeling fully coupled thermal, chemical, hydraulic, and mechanical processes in porous formations that impact drilling and borehole stability. The underlying thermo-chemo-poroelastic model is a system of time-dependent parabolic equations describing thermal, solute, and fluid diffusions coupled with Navier-type elliptic equations that attempt to capture the elastic behavior of rock around a borehole. An existence and uniqueness theory for a corresponding initial-boundary value problem is an open problem in the field. We give sufficient conditions for the well-posedness in the sense of Hadamard of a weak solution to a fully coupled parabolic-elliptic initial-boundary value problem describing homogeneous and isotropic media.

  10. Increase in transmission loss of a double panel system by addition of mass inclusions to a poro-elastic layer: A comparison between theory and experiment

    Science.gov (United States)

    Idrisi, Kamal; Johnson, Marty E.; Toso, Alessandro; Carneal, James P.

    2009-06-01

    This paper is concerned with the modeling and optimization of heterogeneous (HG) blankets, which are used in this investigation to reduce the sound transmission through double panel systems. HG blankets consist of poro-elastic media with small embedded masses, which act similarly to a distributed mass-spring-damper-system. HG blankets have shown significant potential to reduce low frequency radiated sound from structures, where traditional poro-elastic materials have little effect. A mathematical model of a double panel system with an acoustic cavity and HG blanket was developed using impedance and mobility methods. The predicted responses of the source and the receiving panel due to a point force are validated with experimental measurements. The presented results indicate that proper tuning of the HG blankets can result in broadband noise reduction below 500 Hz with less than 10% added mass.

  11. Multiphase poroelastic finite element models for soft tissue structures

    International Nuclear Information System (INIS)

    Simon, B.R.

    1992-01-01

    During the last two decades, biological structures with soft tissue components have been modeled using poroelastic or mixture-based constitutive laws, i.e., the material is viewed as a deformable (porous) solid matrix that is saturated by mobile tissue fluid. These structures exhibit a highly nonlinear, history-dependent material behavior; undergo finite strains; and may swell or shrink when tissue ionic concentrations are altered. Give the geometric and material complexity of soft tissue structures and that they are subjected to complicated initial and boundary conditions, finite element models (FEMs) have been very useful for quantitative structural analyses. This paper surveys recent applications of poroelastic and mixture-based theories and the associated FEMs for the study of the biomechanics of soft tissues, and indicates future directions for research in this area. Equivalent finite-strain poroelastic and mixture continuum biomechanical models are presented. Special attention is given to the identification of material properties using a porohyperelastic constitutive law ans a total Lagrangian view for the formulation. The associated FEMs are then formulated to include this porohyperelastic material response and finite strains. Extensions of the theory are suggested in order to include inherent viscoelasticity, transport phenomena, and swelling in soft tissue structures. A number of biomechanical research areas are identified, and possible applications of the porohyperelastic and mixture-based FEMs are suggested. 62 refs., 11 figs., 3 tabs

  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...

  13. Pore Fluid Effects on Shear Modulus for Sandstones with Soft Anisotropy

    International Nuclear Information System (INIS)

    Berryman, J G

    2004-01-01

    A general analysis of poroelasticity for vertical transverse isotropy (VTI) shows that four eigenvectors are pure shear modes with no coupling to the pore-fluidmechanics. The remaining two eigenvectors are linear combinations of pure compression and uniaxial shear, both of which are coupled to the fluid mechanics. After reducing the problem to a 2x2 system, the analysis shows in a relatively elementary fashion how a poroelastic system with isotropic solid elastic frame, but with anisotropy introduced through the poroelastic coefficients, interacts with the mechanics of the pore fluid and produces shear dependence on fluid properties in the overall mechanical system. The analysis shows, for example, that this effect is always present (though sometimes small in magnitude) in the systems studied, and can be quite large (up to a definite maximum increase of 20 per cent) in some rocks--including Spirit River sandstone and Schuler-Cotton Valley sandstone

  14. Insight into electronic, mechanical and transport properties of quaternary CoVTiAl: Spin-polarized DFT + U approach

    Energy Technology Data Exchange (ETDEWEB)

    Yousuf, Saleem, E-mail: nengroosaleem17@gmail.com; Gupta, D.C., E-mail: sosfizix@gmail.com

    2017-07-15

    Highlights: • 100% spin-polarized material important for the application in spintronics. • It is ferromagnetic and ductile in nature. • Shows semiconducting behavior with a band gap of 1.06 eV. • Possibly efficient high temperature thermoelectric material. - Abstract: We present a preliminary investigation of band structure and thermoelectric properties of new quaternary CoVTiAl Heusler alloy. Structural, magnetic property and 100% spin polarization of equiatomic CoVTiAl predicts ferromagnetic stable ground state. Band profile outlines the indirect semiconducting behavior in spin down channel with band gap of 1.06 eV, and the magnetic moment of 3 µ{sub B} in accordance with Slater-Pauling rule. To evaluate the accuracy of different approximations in predicting thermoelectric properties, the comparison with available experimental data is made which shows fair agreement for the transport coefficients. The high temperature (800 K) positive Seebeck coefficient of 73.71 µV/K describes the p-type character of the material with high efficiency due to highly influential semiconducting behavior around the Fermi level. Considering the combination of 100% spin-polarization, high Seebeck coefficient and large figure of merit, ferromagnetic semiconducting CoVTiAl may prove as a potential candidate for high temperature thermoelectrics and an ideal spin source material for spintronic applications.

  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. Application of a Three-Dimensional Poroelastic BEM to Modeling the Biphasic Mechanics of Cell-Matrix Interactions in Articular Cartilage (REVISION).

    Science.gov (United States)

    Haider, Mansoor A; Guilak, Farshid

    2007-06-15

    Articular cartilage exhibits viscoelasticity in response to mechanical loading that is well described using biphasic or poroelastic continuum models. To date, boundary element methods (BEMs) have not been employed in modeling biphasic tissue mechanics. A three dimensional direct poroelastic BEM, formulated in the Laplace transform domain, is applied to modeling stress relaxation in cartilage. Macroscopic stress relaxation of a poroelastic cylinder in uni-axial confined compression is simulated and validated against a theoretical solution. Microscopic cell deformation due to poroelastic stress relaxation is also modeled. An extended Laplace inversion method is employed to accurately represent mechanical responses in the time domain.

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

    African Journals Online (AJOL)

    DR OKE

    dimensional solution for free vibration problem of homogeneous isotropic cylindrical ... Abousleiman and Cui (1998) presented poroelastic solutions in an inclined ...... The Biot-willis elastic coefficients for a sandstone, Journal of Applied Mechanics, Vol. ... Study of wave motions in fluid-saturated porous rocks, Journal of the ...

  18. Scanning anisotropy parameters in complex media

    KAUST Repository

    Alkhalifah, Tariq Ali

    2011-01-01

    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. 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.

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

    KAUST Repository

    Alkhalifah, Tariq Ali; Fomel, Sergey B.

    2010-01-01

    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.

  1. 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.

  2. 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...

  3. In?situ permeability from integrated poroelastic reflection coefficients

    NARCIS (Netherlands)

    Van Dalen, K.N.; Ghose, R.; Drijkoningen, C.G.; Smeulders, D.M.J.

    2010-01-01

    A reliable estimate of the in?situ permeability of a porous layer in the subsurface is extremely difficult to obtain. We have observed that at the field seismic frequency band the poroelastic behavior for different seismic wavetypes can differ in such a way that their combination gives unique

  4. 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.

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

    African Journals Online (AJOL)

    ... 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 elastic solid are obtained. International Journal of Engineering, Science and Technology, Vol. 2, No. 6, 2010, pp.

  6. 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.

  7. Radial vibrations of an infinitely long poroelastic composite hollow ...

    African Journals Online (AJOL)

    user

    (1997) and Abousleiman and Cui (1998) presented poroelastic solutions in an inclined borehole and transversely ... Basic equations, Formulation and solution of the Problem. The equations of ...... Mechanics and Engineering, Vol.14, pp. 865-877. ... Study of wave motions in fluid-saturated porous rocks, J. Acoust. Soc. Am.

  8. Traveltime computation and imaging from rugged topography in 3D TTI media

    Science.gov (United States)

    Liu, Shaoyong; Wang, Huazhong; Yang, Qinyong; Fang, Wubao

    2014-02-01

    Foothill areas with rugged topography are of great potential for oil and gas seismic exploration, but subsurface imaging in these areas is very challenging. Seismic acquisition with larger offset and wider azimuth is necessary for seismic imaging in complex areas. However, the scale anisotropy in this case must be taken into account. To generalize the pre-stack depth migration (PSDM) to 3D transversely isotropic media with vertical symmetry axes (VTI) and tilted symmetry axes (TTI) from rugged topography, a new dynamic programming approach for the first-arrival traveltime computation method is proposed. The first-arrival time on every uniform mesh point is calculated based on Fermat's principle with simple calculus techniques and a systematic mapping scheme. In order to calculate the minimum traveltime, a set of nonlinear equations is solved on each mesh point, where the group velocity is determined by the group angle. Based on the new first-arrival time calculation method, the corresponding PSDM and migration velocity analysis workflow for 3D anisotropic media from rugged surface is developed. Numerical tests demonstrate that the proposed traveltime calculation method is effective in both VTI and TTI media. The migration results for 3D field data show that it is necessary to choose a smooth datum to remove the high wavenumber move-out components for PSDM with rugged topography and take anisotropy into account to achieve better images.

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

    KAUST Repository

    Pattnaik, Sonali; Tsvankin, Ilya; Wang, Hui; Alkhalifah, Tariq

    2016-01-01

    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

  10. 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.

  11. An analytical model for nanoparticles concentration resulting from infusion into poroelastic brain tissue.

    Science.gov (United States)

    Pizzichelli, G; Di Michele, F; Sinibaldi, E

    2016-02-01

    We consider the infusion of a diluted suspension of nanoparticles (NPs) into poroelastic brain tissue, in view of relevant biomedical applications such as intratumoral thermotherapy. Indeed, the high impact of the related pathologies motivates the development of advanced therapeutic approaches, whose design also benefits from theoretical models. This study provides an analytical expression for the time-dependent NPs concentration during the infusion into poroelastic brain tissue, which also accounts for particle binding onto cells (by recalling relevant results from the colloid filtration theory). Our model is computationally inexpensive and, compared to fully numerical approaches, permits to explicitly elucidate the role of the involved physical aspects (tissue poroelasticity, infusion parameters, NPs physico-chemical properties, NP-tissue interactions underlying binding). We also present illustrative results based on parameters taken from the literature, by considering clinically relevant ranges for the infusion parameters. Moreover, we thoroughly assess the model working assumptions besides discussing its limitations. While not laying any claims of generality, our model can be used to support the development of more ambitious numerical approaches, towards the preliminary design of novel therapies based on NPs infusion into brain tissue. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. 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.

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

    KAUST Repository

    Karve, P. M.; Kallivokas, L. F.

    2015-01-01

    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

  14. 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.

  15. Traveltime computation and imaging from rugged topography in 3D TTI media

    International Nuclear Information System (INIS)

    Liu, Shaoyong; Wang, Huazhong; Yang, Qinyong; Fang, Wubao

    2014-01-01

    Foothill areas with rugged topography are of great potential for oil and gas seismic exploration, but subsurface imaging in these areas is very challenging. Seismic acquisition with larger offset and wider azimuth is necessary for seismic imaging in complex areas. However, the scale anisotropy in this case must be taken into account. To generalize the pre-stack depth migration (PSDM) to 3D transversely isotropic media with vertical symmetry axes (VTI) and tilted symmetry axes (TTI) from rugged topography, a new dynamic programming approach for the first-arrival traveltime computation method is proposed. The first-arrival time on every uniform mesh point is calculated based on Fermat's principle with simple calculus techniques and a systematic mapping scheme. In order to calculate the minimum traveltime, a set of nonlinear equations is solved on each mesh point, where the group velocity is determined by the group angle. Based on the new first-arrival time calculation method, the corresponding PSDM and migration velocity analysis workflow for 3D anisotropic media from rugged surface is developed. Numerical tests demonstrate that the proposed traveltime calculation method is effective in both VTI and TTI media. The migration results for 3D field data show that it is necessary to choose a smooth datum to remove the high wavenumber move-out components for PSDM with rugged topography and take anisotropy into account to achieve better images. (paper)

  16. Simulation of ultrasonic wave propagation in anisotropic poroelastic bone plate using hybrid spectral/finite element method.

    Science.gov (United States)

    Nguyen, Vu-Hieu; Naili, Salah

    2012-08-01

    This paper deals with the modeling of guided waves propagation in in vivo cortical long bone, which is known to be anisotropic medium with functionally graded porosity. The bone is modeled as an anisotropic poroelastic material by using Biot's theory formulated in high frequency domain. A hybrid spectral/finite element formulation has been developed to find the time-domain solution of ultrasonic waves propagating in a poroelastic plate immersed in two fluid halfspaces. The numerical technique is based on a combined Laplace-Fourier transform, which allows to obtain a reduced dimension problem in the frequency-wavenumber domain. In the spectral domain, as radiation conditions representing infinite fluid halfspaces may be exactly introduced, only the heterogeneous solid layer needs to be analyzed by using finite element method. Several numerical tests are presented showing very good performance of the proposed procedure. A preliminary study on the first arrived signal velocities computed by using equivalent elastic and poroelastic models will be presented. Copyright © 2012 John Wiley & Sons, Ltd.

  17. 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.

  18. Upscaling in porous media : Consequences of reducing the phase on the dynamic behavior of a homogenized medium

    NARCIS (Netherlands)

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

    2014-01-01

    Effective-medium approaches are widely used to model initially heterogeneous systems: it saves computational time. In poroelasticity (two-phase media), it is advantageous to use one-phase effective medium if possible: it simplifies computations even more. In this paper we discuss situations where

  19. Generalization of Eshelby close-quote s Formula for a Single Ellipsoidal Elastic Inclusion to Poroelasticity and Thermoelasticity

    International Nuclear Information System (INIS)

    Berryman, J.G.

    1997-01-01

    Eshelby close-quote s formula gives the response of a single ellipsoidal elastic inclusion in an elastic whole space to a uniform strain imposed at infinity. Using a linear combination of results from two simple thought experiments, we show how this formula may be generalized to both poroelasticity and thermoelasticity. The resulting new formulas are important for applications to analysis of poroelastic and thermoelastic composites, including but not restricted to rocks. copyright 1997 The American Physical Society

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

    African Journals Online (AJOL)

    user

    Biot's poroelastic theory is employed to investigate stresses under an ... Keywords: Flat slab, radial normal stress, pervious surface, impervious ... warranted, because of above mentioned applications. ...... M.Tajuddin, and G. Narayan Reddy, Effect of boundaries on the dynamic interaction of a liquid filled porous layer and a.

  1. Shear Wave Splitting analysis of borehole microseismic reveals weak azimuthal anisotropy hidden behind strong VTI fabric of Lower Paleozoic shales in northern Poland

    Science.gov (United States)

    Gajek, Wojciech; Verdon, James; Malinowski, Michał; Trojanowski, Jacek

    2017-04-01

    Azimuthal anisotropy plays a key-role in hydraulic fracturing experiments, since it provides information on stress orientation and pre-existing fracture system presence. The Lower Paleozoic shale plays in northern Poland are characterized by a strong (15-18%) Vertical Transverse Isotropy (VTI) fabric which dominates weak azimuthal anisotropy being of order of 1-2%. A shear wave travelling in the subsurface after entering an anisotropic medium splits into two orthogonally polarized waves travelling with different velocities. Splitting parameters which can be assessed using a microseismic array are polarization of the fast shear wave and time delay between two modes. Polarization of the fast wave characterizes the anisotropic system on the wave path while the time delay is proportional to the magnitude of anisotropy. We employ Shear Wave Splitting (SWS) technique using a borehole microseismic dataset collected during a hydraulic stimulation treatment located in northern Poland, to image fracture strike masked by a strong VTI signature. During the inversion part, the VTI background parameters were kept constant using information from 3D seismic (VTI model used for pre-stack depth migration). Obtained fracture azimuths averaged over fracturing stages are consistent with the available XRMI imager logs from the nearby vertical well, however they are different from the large-scale maximum stress direction (by 40-45 degrees). Inverted Hudson's crack density (ca. 2%) are compatible with the low shear-wave anisotropy observed in the cross-dipole sonic logs (1-2%). This work has been funded by the Polish National Centre for Research and Development within the Blue Gas project (No BG2/SHALEMECH/14). Data were provided by the PGNiG SA. Collaboration with University of Bristol was supported within TIDES COST Action ES1401.

  2. Optimal variable-grid finite-difference modeling for porous media

    International Nuclear Information System (INIS)

    Liu, Xinxin; Yin, Xingyao; Li, Haishan

    2014-01-01

    Numerical modeling of poroelastic waves by the finite-difference (FD) method is more expensive than that of acoustic or elastic waves. To improve the accuracy and computational efficiency of seismic modeling, variable-grid FD methods have been developed. In this paper, we derived optimal staggered-grid finite difference schemes with variable grid-spacing and time-step for seismic modeling in porous media. FD operators with small grid-spacing and time-step are adopted for low-velocity or small-scale geological bodies, while FD operators with big grid-spacing and time-step are adopted for high-velocity or large-scale regions. The dispersion relations of FD schemes were derived based on the plane wave theory, then the FD coefficients were obtained using the Taylor expansion. Dispersion analysis and modeling results demonstrated that the proposed method has higher accuracy with lower computational cost for poroelastic wave simulation in heterogeneous reservoirs. (paper)

  3. Cells competition in tumor growth poroelasticity

    Science.gov (United States)

    Fraldi, Massimiliano; Carotenuto, Angelo R.

    2018-03-01

    Growth of biological tissues has been recently treated within the framework of Continuum Mechanics, by adopting heterogeneous poroelastic models where the interaction between soft matrix and interstitial fluid flow is coupled with inelastic effects ad hoc introduced to simulate the macroscopic volumetric growth determined by cells division, cells growth and extracellular matrix changes occurring at the micro-scale level. These continuum models seem to overcome some limitations intrinsically associated to other alternative approaches based on mass balances in multiphase systems, because the crucial role played by residual stresses accompanying growth and nutrients walkway is preserved. Nevertheless, when these strategies are applied to analyze solid tumors, mass growth is usually assigned in a prescribed form that essentially copies the in vitro measured intrinsic growth rates of the cell species. As a consequence, some important cell-cell dynamics governing mass evolution and invasion rates of cancer cells, as well as their coupling with feedback mechanisms associated to in situ stresses, are inevitably lost and thus the spatial distribution and the evolution with time of the growth inside the tumor -which would be results rather than inputs- are forced to enter in the model simply as data. In order to solve this paradox, it is here proposed an enhanced multi-scale poroelastic model undergoing large deformations and embodying inelastic growth, where the net growth terms directly result from the "interspecific" predator-prey (Volterra/Lotka-like) competition occurring at the micro-scale level between healthy and abnormal cell species. In this way, a system of fully-coupled non-linear PDEs is derived to describe how the fight among cell species to grab the available common resources, stress field, pressure gradients, interstitial fluid flows driving nutrients and inhomogeneous growth all simultaneously interact to decide the tumor fate.

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

    KAUST Repository

    Jeong, C.; Kallivokas, L. F.

    2016-01-01

    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.

  5. 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.

  6. 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 formulate 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 ...

  7. 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.

  8. Recovery characteristics of neutron-irradiated V-Ti alloys

    International Nuclear Information System (INIS)

    Leguey, T.; Pareja, R.

    2000-01-01

    The recovery characteristics of neutron-irradiated pure V and V-Ti alloys with 1.0 and 4.5 at.% Ti have been investigated by positron annihilation spectroscopy. Microvoid formation during irradiation at 320 K is produced in pure V and V-1Ti but not in V-4.5Ti. The results are consistent with a model of swelling inhibition induced by vacancy trapping by solute Ti during irradiation. The temperature dependencies of the parameter S in the range 8-300 K indicate a large dislocation bias for vacancies and solute Ti. This dislocation bias prevents the microvoid nucleation in V-4.5Ti, and the microvoid growth in V-1Ti, when vacancies become mobile during post-irradiation annealing treatments. A characteristic increase of the positron lifetime is found during recovery induced by isochronal annealing. It is attributed to a vacancy accumulation into the lattice of Ti oxides precipitated during cooling down, or at their matrix/precipitate interfaces. These precipitates could be produced by the decomposition of metastable phases of Ti oxides formed during post-irradiation annealing above 1000 K

  9. Modeling the poroelastic response to megathrust earthquakes: A look at the 2012 Mw 7.6 Costa Rican event

    Science.gov (United States)

    McCormack, Kimberly A.; Hesse, Marc A.

    2018-04-01

    We model the subsurface hydrologic response to the 7.6 Mw subduction zone earthquake that occurred on the plate interface beneath the Nicoya peninsula in Costa Rica on September 5, 2012. The regional-scale poroelastic model of the overlying plate integrates seismologic, geodetic and hydrologic data sets to predict the post-seismic poroelastic response. A representative two-dimensional model shows that thrust earthquakes with a slip width less than a third of their depth produce complex multi-lobed pressure perturbations in the shallow subsurface. This leads to multiple poroelastic relaxation timescales that may overlap with the longer viscoelastic timescales. In the three-dimensional model, the complex slip distribution of 2012 Nicoya event and its small width to depth ratio lead to a pore pressure distribution comprising multiple trench parallel ridges of high and low pressure. This leads to complex groundwater flow patterns, non-monotonic variations in predicted well water levels, and poroelastic relaxation on multiple time scales. The model also predicts significant tectonically driven submarine groundwater discharge off-shore. In the weeks following the earthquake, the predicted net submarine groundwater discharge in the study area increases, creating a 100 fold increase in net discharge relative to topography-driven flow over the first 30 days. Our model suggests the hydrological response on land is more complex than typically acknowledged in tectonic studies. This may complicate the interpretation of transient post-seismic surface deformations. Combined tectonic-hydrological observation networks have the potential to reduce such ambiguities.

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

    KAUST Repository

    Brown, Donald; Popov, Peter V.; Efendiev, Yalchin R.

    2012-01-01

    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.

  11. 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.

  12. Mobility Effect on Poroelastic Seismic Signatures in Partially Saturated Rocks With Applications in Time-Lapse Monitoring of a Heavy Oil Reservoir

    Science.gov (United States)

    Zhao, Luanxiao; Yuan, Hemin; Yang, Jingkang; Han, De-hua; Geng, Jianhua; Zhou, Rui; Li, Hui; Yao, Qiuliang

    2017-11-01

    Conventional seismic analysis in partially saturated rocks normally lays emphasis on estimating pore fluid content and saturation, typically ignoring the effect of mobility, which decides the ability of fluids moving in the porous rocks. Deformation resulting from a seismic wave in heterogeneous partially saturated media can cause pore fluid pressure relaxation at mesoscopic scale, thereby making the fluid mobility inherently associated with poroelastic reflectivity. For two typical gas-brine reservoir models, with the given rock and fluid properties, the numerical analysis suggests that variations of patchy fluid saturation, fluid compressibility contrast, and acoustic stiffness of rock frame collectively affect the seismic reflection dependence on mobility. In particular, the realistic compressibility contrast of fluid patches in shallow and deep reservoir environments plays an important role in determining the reflection sensitivity to mobility. We also use a time-lapse seismic data set from a Steam-Assisted Gravity Drainage producing heavy oil reservoir to demonstrate that mobility change coupled with patchy saturation possibly leads to seismic spectral energy shifting from the baseline to monitor line. Our workflow starts from performing seismic spectral analysis on the targeted reflectivity interface. Then, on the basis of mesoscopic fluid pressure diffusion between patches of steam and heavy oil, poroelastic reflectivity modeling is conducted to understand the shift of the central frequency toward low frequencies after the steam injection. The presented results open the possibility of monitoring mobility change of a partially saturated geological formation from dissipation-related seismic attributes.

  13. Refinement of elastic, poroelastic, and osmotic tissue properties of intervertebral disks to analyze behavior in compression.

    Science.gov (United States)

    Stokes, Ian A F; Laible, Jeffrey P; Gardner-Morse, Mack G; Costi, John J; Iatridis, James C

    2011-01-01

    Intervertebral disks support compressive forces because of their elastic stiffness as well as the fluid pressures resulting from poroelasticity and the osmotic (swelling) effects. Analytical methods can quantify the relative contributions, but only if correct material properties are used. To identify appropriate tissue properties, an experimental study and finite element analytical simulation of poroelastic and osmotic behavior of intervertebral disks were combined to refine published values of disk and endplate properties to optimize model fit to experimental data. Experimentally, nine human intervertebral disks with adjacent hemi-vertebrae were immersed sequentially in saline baths having concentrations of 0.015, 0.15, and 1.5 M and the loss of compressive force at constant height (force relaxation) was recorded over several hours after equilibration to a 300-N compressive force. Amplitude and time constant terms in exponential force-time curve-fits for experimental and finite element analytical simulations were compared. These experiments and finite element analyses provided data dependent on poroelastic and osmotic properties of the disk tissues. The sensitivities of the model to alterations in tissue material properties were used to obtain refined values of five key material parameters. The relaxation of the force in the three bath concentrations was exponential in form, expressed as mean compressive force loss of 48.7, 55.0, and 140 N, respectively, with time constants of 1.73, 2.78, and 3.40 h. This behavior was analytically well represented by a model having poroelastic and osmotic tissue properties with published tissue properties adjusted by multiplying factors between 0.55 and 2.6. Force relaxation and time constants from the analytical simulations were most sensitive to values of fixed charge density and endplate porosity.

  14. A parametric model order reduction technique for poroelastic finite element models.

    Science.gov (United States)

    Lappano, Ettore; Polanz, Markus; Desmet, Wim; Mundo, Domenico

    2017-10-01

    This research presents a parametric model order reduction approach for vibro-acoustic problems in the frequency domain of systems containing poroelastic materials (PEM). The method is applied to the Finite Element (FE) discretization of the weak u-p integral formulation based on the Biot-Allard theory and makes use of reduced basis (RB) methods typically employed for parametric problems. The parametric reduction is obtained rewriting the Biot-Allard FE equations for poroelastic materials using an affine representation of the frequency (therefore allowing for RB methods) and projecting the frequency-dependent PEM system on a global reduced order basis generated with the proper orthogonal decomposition instead of standard modal approaches. This has proven to be better suited to describe the nonlinear frequency dependence and the strong coupling introduced by damping. The methodology presented is tested on two three-dimensional systems: in the first experiment, the surface impedance of a PEM layer sample is calculated and compared with results of the literature; in the second, the reduced order model of a multilayer system coupled to an air cavity is assessed and the results are compared to those of the reference FE model.

  15. Poroelastic behaviour of the degenerating human intervertebral disc: a ten-day study in a loaded disc culture system

    Directory of Open Access Journals (Sweden)

    KS Emanuel

    2015-06-01

    Full Text Available The intervertebral disc (IVD allows flexibility to the vertebral column, and transfers the predominant axial loads during daily activities. Its axial biomechanical behaviour is poroelastic, due to the water-binding and releasing capacity of the nucleus pulposus. Degeneration of the intervertebral disc presumably affects both the instantaneous elastic response to the load on the IVD and the subsequent interstitial flow of fluid. This study aims to quantify the poroelastic behaviour of the IVD and its change with degeneration, as defined by the magnetic resonance imaging-based Pfirrmann Score (PS. For a period of ten days, 36 human lumbar IVDs were loaded with a simulated physiological axial loading regime, while deformation was monitored. The IVDs responded to the loads with instantaneous elastic and slow poroelastic axial deformation. Several mechanical parameters changed throughout the first five days of the experiment, until the IVDs settled into a dynamic equilibrium. In this equilibrium, degeneration was significantly related to a decrease in disc height loss during the daytime high load phase (ρ = -0.49, and to a decrease in the rate of this deformation during the final half hour of each day (ρ = -0.53. These properties were related to the nucleus glycosaminoglycan/hydroxyproline (GAG/HYP ratio, rather than GAG content alone, indicating that remodelling of the extracellular matrix reduces poroelastic properties of the IVD. This implies that the degenerated discs have a reduced capacity to bind water and/or a reduced resistance against fluid flow. The resulting loss in hydrostatic pressure may further change cell behaviour in the nucleus pulposus.

  16. 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

  17. Modeling Poroelastic Wave Propagation in a Real 2-D Complex Geological Structure Obtained via Self-Organizing Maps

    Science.gov (United States)

    Itzá Balam, Reymundo; Iturrarán-Viveros, Ursula; Parra, Jorge O.

    2018-03-01

    Two main stages of seismic modeling are geological model building and numerical computation of seismic response for the model. The quality of the computed seismic response is partly related to the type of model that is built. Therefore, the model building approaches become as important as seismic forward numerical methods. For this purpose, three petrophysical facies (sands, shales and limestones) are extracted from reflection seismic data and some seismic attributes via the clustering method called Self-Organizing Maps (SOM), which, in this context, serves as a geological model building tool. This model with all its properties is the input to the Optimal Implicit Staggered Finite Difference (OISFD) algorithm to create synthetic seismograms for poroelastic, poroacoustic and elastic media. The results show a good agreement between observed and 2-D synthetic seismograms. This demonstrates that the SOM classification method enables us to extract facies from seismic data and allows us to integrate the lithology at the borehole scale with the 2-D seismic data.

  18. Sound transmission through a double-panel construction lined with poroelastic material in the presence of mean flow

    Science.gov (United States)

    Zhou, Jie; Bhaskar, Atul; Zhang, Xin

    2013-08-01

    This paper investigates the sound transmission characteristics through a system of double-panel lined with poroelastic material in the core. The panels are surrounded by external and internal fluid media where a uniform external mean flow exists on one side. Biot's theory is used to model the porous material. Three types of constructions—bonded-bonded, bonded-unbonded and unbonded-unbonded—are considered. The effect of Mach number of the external flow on the sound transmission over a wide frequency range in a diffuse sound field is examined. External mean flow is shown to give a modest increase in transmission loss at low frequency, but a significant increase at high frequency. It is brought out that calculations based on static air on the incidence side provide a conservative estimate of sound transmission through the sandwich structure. The acoustic performance of the sandwich panel for different configurations is presented. The effect of curvature of the panel is also brought out by using shallow shell theory.

  19. Sound transmission through triple-panel structures lined with poroelastic materials

    OpenAIRE

    Liu, Y

    2015-01-01

    In this paper, previous theories on the prediction of sound transmission loss for a double-panel structure lined with poroelastic materials are extended to address the problem of a triple-panel structure. Six typical configurations are considered for a triple-panel structure based on the method of coupling the porous layers to the facing panels which determines critically the sound insulation performance of the system. The transfer matrix method is employed to solve the system by applying app...

  20. Transport, Structural and Mechanical Properties of Quaternary FeVTiAl Alloy

    Science.gov (United States)

    Bhat, Tahir Mohiuddin; Gupta, Dinesh C.

    2016-11-01

    The electronic, structural, magnetic and transport properties of FeVTiAl quaternary alloy have been investigated within the framework of density functional theory. The material is a completely spin-polarized half-metallic ferromagnet in its ground state with F-43m structure. The structural stability was further confirmed by elastic constants in the cubic phase with high Young's modulus and brittle nature. The present study predicts an energy band gap of 0.72 eV in a localized minority spin channel at equilibrium lattice parameter of 6.00 Å. The transport properties of the material are discussed based on the Seebeck coefficient, and electrical and thermal conductivity coefficients. The alloy presents large values of Seebeck coefficients, ~39 μV K-1 at room temperature (300 K), and has an excellent thermoelectric performance with ZT = ~0.8.

  1. Inverse problem in anisotropic poroelasticity: drained constants from undrained ultrasound measurements.

    Science.gov (United States)

    Berryman, James G; Nakagawa, Seiji

    2010-02-01

    Poroelastic analysis has traditionally focused on the relationship between dry and 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 effects of the fluids 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 fluid 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.

  2. 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.

  3. Sound transmission through lined, composite panel structures: Transversely isotropic poro-elastic model

    Science.gov (United States)

    Kim, Jeong-Woo

    A joint experimental and analytical investigation of the sound transmission loss (STL) and two-dimensional free wave propagation in composite sandwich panels is presented here. An existing panel, a Nomex honeycomb sandwich panel, was studied in detail. For the purpose of understanding the typical behavior of sandwich panels, a composite structure comprising two aluminum sheets with a relatively soft, poro-elastic foam core was also constructed and studied. The cores of both panels were modeled using an anisotropic (transversely isotropic) poro-elastic material theory. Several estimation methods were used to obtain the material properties of the honeycomb core and the skin plates to be used in the numerical calculations. Appropriate values selected from among the estimates were used in the STL and free wave propagation models. The prediction model was then verified in two ways: first, the calculated wave speeds and STL of a single poro-elastic layer were numerically verified by comparison with the predictions of a previously developed isotropic model. Secondly, to physically validate the transversely isotropic model, the measured STL and the phase speeds of the sandwich panels were compared with their predicted values. To analyze the actual treatment of a fuselage structure, multi-layered configurations, including a honeycomb panel and several layers such as air gaps, acoustic blankets and membrane partitions, were formulated. Then, to find the optimal solution for improving the sound barrier performance of an actual fuselage system, air layer depth and glass fiber lining effects were investigated by using these multi-layer models. By using the free wave propagation model, the first anti-symmetric and symmetric modes of the sandwich panels were characterized to allow the identification of the coincidence frequencies of the sandwich panel. The behavior of the STL could then be clearly explained by comparison with the free wave propagation solutions. By performing a

  4. Analysis of Dynamic Fracture Compliance Based on Poroelastic Theory - Part II: Results of Numerical and Experimental Tests

    Science.gov (United States)

    Wang, Ding; Ding, Pin-bo; Ba, Jing

    2018-03-01

    In Part I, a dynamic fracture compliance model (DFCM) was derived based on the poroelastic theory. The normal compliance of fractures is frequency-dependent and closely associated with the connectivity of porous media. In this paper, we first compare the DFCM with previous fractured media theories in the literature in a full frequency range. Furthermore, experimental tests are performed on synthetic rock specimens, and the DFCM is compared with the experimental data in the ultrasonic frequency band. Synthetic rock specimens saturated with water have more realistic mineral compositions and pore structures relative to previous works in comparison with natural reservoir rocks. The fracture/pore geometrical and physical parameters can be controlled to replicate approximately those of natural rocks. P- and S-wave anisotropy characteristics with different fracture and pore properties are calculated and numerical results are compared with experimental data. Although the measurement frequency is relatively high, the results of DFCM are appropriate for explaining the experimental data. The characteristic frequency of fluid pressure equilibration calculated based on the specimen parameters is not substantially less than the measurement frequency. In the dynamic fracture model, the wave-induced fluid flow behavior is an important factor for the fracture-wave interaction process, which differs from the models at the high-frequency limits, for instance, Hudson's un-relaxed model.

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

    Czech Academy of Sciences Publication Activity Database

    Roubíček, Tomáš

    2017-01-01

    Roč. 29, č. 2 (2017), s. 625-646 ISSN 0935-1175 R&D Projects: GA ČR(CZ) GA16-03823S; GA ČR GA14-15264S Institutional support: RVO:61388998 Keywords : poro-elastic rocks * damage * biot model Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 2.529, year: 2016 https://link.springer.com/article/10.1007/s00161-016-0547-5

  6. Stable discretization of poroelasticity problems and efficient preconditioners for arising saddle point type matrices

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe; Blaheta, Radim; Byczanski, Petr

    2012-01-01

    Roč. 15, č. 4 (2012), s. 191-207 ISSN 1432-9360 R&D Projects: GA MŠk ED1.1.00/02.0070 Institutional support: RVO:68145535 Keywords : poroelasticity * saddle point matrices * preconditioning * stability of discretization Subject RIV: BA - General Mathematics http://link.springer.com/article/10.1007/s00791-013-0209-0

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

    KAUST Repository

    Zhan, Ge; Pestana, Reynam C.; Stoffa, Paul L.

    2012-01-01

    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.

  8. 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.

  9. Effect of Ti solute on the recovery of cold-rolled V-Ti alloys

    International Nuclear Information System (INIS)

    Leguey, T.; Munoz, A.; Pareja, R.

    1999-01-01

    The recovery characteristics of cold-rolled pure V and V-Ti alloys with compositions of 0.3, 1 and 4.5 at.% Ti have been investigated by positron annihilation spectroscopy. The recovery is accomplished in two stages. Fifty percent cold rolling induces the formation of microvoids in V-0.3Ti and V-1Ti but not in V-4.5Ti. The first recovery stage in pure V, V-0.3Ti and V-1Ti starts with the dissolution of microvoids. The recovery curves of the annihilation parameters for the alloys indicate the formation of Ti-rich precipitates during the first recovery stage. These precipitates act as very efficient vacancy sinks. The second recovery stage starting for annealing temperatures above ≅1150 K is attributed to annealing of vacancies associated to the precipitates. (orig.)

  10. Effective stress principle for partially saturated media

    International Nuclear Information System (INIS)

    McTigue, D.F.; Wilson, R.K.; Nunziato, J.W.

    1984-04-01

    In support of the Nevada Nuclear Waste Storage Investigation (NNWSI) Project, we have undertaken a fundamental study of water migration in partially saturated media. One aspect of that study, on which we report here, has been to use the continuum theory of mixtures to extend the classical notion of effective stress to partially saturated media. Our analysis recovers previously proposed phenomenological representations for the effective stress in terms of the capillary pressure. The theory is illustrated by specializing to the case of linear poroelasticity, for which we calculate the deformation due to the fluid pressure in a static capillary fringe. We then examine the transient consolidation associated with liquid flow induced by an applied surface load. Settlement accompanies this flow as the liquid is redistributed by a nonlinear diffusion process. For material properties characteristic of tuff from the Nevada Test Site, these effects are found to be vanishingly small. 14 references, 7 figures, 1 table

  11. Transient poroelastic stress coupling between the 2015 M7.8 Gorkha, Nepal earthquake and its M7.3 aftershock

    Science.gov (United States)

    Tung, S.; Masterlark, T.; Dovovan, T.

    2018-05-01

    The large M7.3 aftershock occurred 17 days after the 2015 M7.8 Gorkha earthquake. We investigate if this sequence is mechanically favored by the mainshock via time-dependent fluid migration and pore pressure recovery. This study uses finite element models of fully-coupled poroelastic coseismic and postseismic behavior to simulate the evolving stress and pore-pressure fields. Using simulations of a reasonable permeability, the hypocenter was destabilized by an additional 0.15 MPa of Coulomb failure stress change (ΔCFS) and 0.17 MPa of pore pressure (Δp), the latter of which induced lateral and upward diffusive fluid flow (up to 2.76 mm/day) in the aftershock region. The M7.3 location is predicted next to a local maximum of Δp and a zone of positive ΔCFS northeast of Kathmandu. About 60% of the aftershocks occurred within zones having either Δp > 0 or ΔCFS > 0. Particularly in the eastern flank of the epicentral area, 83% of the aftershocks experienced postseismic fluid pressurization and 88% of them broke out with positive pore pressure, which are discernibly more than those with positive ΔCFS (71%). The transient scalar field of fluid pressurization provides a good proxy to predict aftershock-prone areas in space and time, because it does not require extraction of an assumed vector field from transient stress tensor fields as is the case for ΔCFS calculations. A bulk permeability of 8.32 × 10-18 m2 is resolved to match the transient response and the timing of the M7.3 rupture which occurred at the peak of the ΔCFS time-series. This estimate is consistent with the existing power-law permeability-versus-depth models, suggesting an intermediately-fractured upper crust coherent with the local geology of the central Himalayas. The contribution of poroelastic triggering is verified against different poroelastic moduli and surface flow-pressure boundaries, suggesting that a poroelastic component is essential to account for the time interval separating the

  12. Poroelastic behaviour of the degenerating human intervertebral disc: a ten-day study in a loaded disc culture system

    NARCIS (Netherlands)

    Emanuel, K. S.; Vergroesen, P.-P. A.; Peeters, M.; Holewijn, R. M.; Kingma, I.; Smit, T. H.

    2015-01-01

    The intervertebral disc (IVD) allows flexibility to the vertebral column, and transfers the predominant axial loads during daily activities. Its axial biomechanical behaviour is poroelastic, due to the water-binding and releasing capacity of the nucleus pulposus. Degeneration of the intervertebral

  13. A physical model study of the travel times and conversion point locations of P-SV converted waves in vertical transversely isotropic media

    Science.gov (United States)

    Tseng, C.

    2013-12-01

    In exploration seismology, subsurface medium commonly exhibits anisotropy, characterized by a vertical transversely isotropic (VTI) model. Due to the need of exploring small reservoirs in complex structures, the seismic exploration is extended to deal with anisotropic media. The P-S converted wave seismic exploration is a relatively inexpensive, broadly applicable, and effective way to obtain the S-wave information of the medium. In anisotropic traveltime analysis, the moveout curve of horizontal P-SV event can help to determine the ratio of the P- and SV-wave vertical velocities, the normal moveout (NMO) velocity of SV-waves, and the anisotropy parameters. The P-SV conversion point (CP) location is of great importance to P-SV data binning, NMO corrections and common conversion point (CCP) stacking, and the anisotropy has a more significant effect on the conversion point location than on the moveout. In this study, we attempt to inspect the theoretical non-hyperbolic moveout and CP equations for the P-SV waves reflected from a VTI layer by numerical calculations and physical modeling. We are also interested in visualizing the variations of the conversion point locations from a designed VTI medium. In traveltime analysis, the theoretical moveout curve is accurate up to offsets about one and a half times the reflector depth (x/z=1.5). However, the moveout curve computed by Fermat's principle fits well to the physical data. The CP locations of P-SV waves are similar to those calculated by Fermat's principle and theoretical CP equation, which are verified by the physical modeling.

  14. Skinfold creep under load of caliper. Linear visco- and poroelastic model simulations.

    Science.gov (United States)

    Nowak, Joanna; Nowak, Bartosz; Kaczmarek, Mariusz

    2015-01-01

    This paper addresses the diagnostic idea proposed in [11] to measure the parameter called rate of creep of axillary fold of tissue using modified Harpenden skinfold caliper in order to distinguish normal and edematous tissue. Our simulations are intended to help understanding the creep phenomenon and creep rate parameter as a sensitive indicator of edema existence. The parametric analysis shows the tissue behavior under the external load as well as its sensitivity to changes of crucial hydro-mechanical tissue parameters, e.g., permeability or stiffness. The linear viscoelastic and poroelastic models of normal (single phase) and oedematous tissue (twophase: swelled tissue with excess of interstitial fluid) implemented in COMSOL Multiphysics environment are used. Simulations are performed within the range of small strains for a simplified fold geometry, material characterization and boundary conditions. The predicted creep is the result of viscosity (viscoelastic model) or pore fluid displacement (poroelastic model) in tissue. The tissue deformations, interstitial fluid pressure as well as interstitial fluid velocity are discussed in parametric analysis with respect to elasticity modulus, relaxation time or permeability of tissue. The creep rate determined within the models of tissue is compared and referred to the diagnostic idea in [11]. The results obtained from the two linear models of subcutaneous tissue indicate that the form of creep curve and the creep rate are sensitive to material parameters which characterize the tissue. However, the adopted modelling assumptions point to a limited applicability of the creep rate as the discriminant of oedema.

  15. 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.

  16. Stresses, strains, and displacements in a poroelastic layered pavement model subject to a moving load

    International Nuclear Information System (INIS)

    Morshedi, C.

    1982-01-01

    The response of a layered poroelastic halfspace to a progressing normally distributed load applied at the surface is evaluated for the case in which the constant velocity of the moving load is less than that of the elastic waves in each layer. It is assumed that a steady state exists with respect to the coordinate axes attached to a moving load. A three-dimensional problem for Biot's consolidated equations is then solved by taking Fourier transforms in the horizontal directions to evaluate stresses and displacements at any point in the medium. The analysis is illustrated by numerical examples using an algorithm based on one previously developed to calculate the response to a static load for axisymmetric poroelastic layers. To reduce the amount of computation, attention is restricted to a two-dimensional problem in which the load extends infinitely in the transverse direction. Results are presented for two and three-layered pavement models composed of concrete and gravel over a clay subbase responding to moving traffic, but the method is applicable to any number of layers. The effect of varying the velocity of the load and layer properties is observed

  17. Biochemomechanical poroelastic theory of avascular tumor growth

    Science.gov (United States)

    Xue, Shi-Lei; Li, Bo; Feng, Xi-Qiao; Gao, Huajian

    2016-09-01

    Tumor growth is a complex process involving genetic mutations, biochemical regulations, and mechanical deformations. In this paper, a thermodynamics-based nonlinear poroelastic theory is established to model the coupling among the mechanical, chemical, and biological mechanisms governing avascular tumor growth. A volumetric growth law accounting for mechano-chemo-biological coupled effects is proposed to describe the development of solid tumors. The regulating roles of stresses and nutrient transport in the tumor growth are revealed under different environmental constraints. We show that the mechano-chemo-biological coupling triggers anisotropic and heterogeneous growth, leading to the formation of layered structures in a growing tumor. There exists a steady state in which tumor growth is balanced by resorption. The influence of external confinements on tumor growth is also examined. A phase diagram is constructed to illustrate how the elastic modulus and thickness of the confinements jointly dictate the steady state of tumor volume. Qualitative and quantitative agreements with experimental observations indicate the developed model is capable of capturing the essential features of avascular tumor growth in various environments.

  18. 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.

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

    KAUST Repository

    Waheed, Umair bin; Flagg, Garret; Yarman, Can Evren

    2016-01-01

    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.

  20. 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.

  1. 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.

  2. Determination of the Mass Absorption Coefficient in Two-Layer Ti/V and V/Ti Thin Film Systems by the X-Ray Fluorescence Method

    Science.gov (United States)

    Mashin, N. I.; Chernyaeva, E. A.; Tumanova, A. N.; Gafarova, L. M.

    2016-03-01

    A new XRF procedure for the determination of the mass absorption coefficient in thin film Ti/V and V/Ti two-layer systems has been proposed. The procedure uses easy-to-make thin-film layers of sputtered titanium and vanadium on a polymer film substrate. Correction coefficients have been calculated that take into account attenuation of primary radiation of the X-ray tube, as well as attenuation of the spectral line of the bottom layer element in the top layer.

  3. 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.

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

    KAUST Repository

    Djebbi, Ramzi; Alkhalifah, Tariq Ali

    2015-01-01

    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. 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.

  6. Wellbore stability in shales considering chemo-poroelastic effects

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Ewerton M.P.; Pastor, Jorge A.S.C.; Fontoura, Sergio A.B.; Rabe, Claudio [Pontificia Univ. Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil). Dept. de Engenharia Civil. Grupo de Tecnologia e Engenharia de Petroleo

    2004-07-01

    Under compaction and low geothermal gradients are deep water characteristics. Both under compaction and low geothermal gradients generate considerable thickness of smectite-rich shales. These rocks are the major source of wellbore stability problems, because they are susceptible to adverse physico-chemical reactions when in contact with inadequate drilling fluids. Due shales are low permeability rocks diffusion processes dominate the changes of pore pressure around wellbore. Diffusion of fluids, ions and temperature occurs in shales during drilling and demand a fully coupled modelling taking account these factors. Despite temperature importance, in this paper wellbore stability in shales is analyzed through a model that considers only the coupling between poroelastic and physico-chemical effects. The coupled equations are solved analytically and have been implemented in a computational simulator with user-friendly interface. Time-dependent simulations of wellbore stability in shales are presented for a typical deep water scenario. The results show that physico-chemical effects change pore pressure around wellbore and have high impact on the wellbore stability. (author)

  7. Parameterization analysis and inversion for orthorhombic media

    KAUST Repository

    Masmoudi, Nabil

    2018-05-01

    Accounting for azimuthal anisotropy is necessary for the processing and inversion of wide-azimuth and wide-aperture seismic data because wave speeds naturally depend on the wave propagation direction. Orthorhombic anisotropy is considered the most effective anisotropic model that approximates the azimuthal anisotropy we observe in seismic data. In the framework of full wave form inversion (FWI), the large number of parameters describing orthorhombic media exerts a considerable trade-off and increases the non-linearity of the inversion problem. Choosing a suitable parameterization for the model, and identifying which parameters in that parameterization could be well resolved, are essential to a successful inversion. In this thesis, I derive the radiation patterns for different acoustic orthorhombic parameterization. Analyzing the angular dependence of the scattering of the parameters of different parameterizations starting with the conventionally used notation, I assess the potential trade-off between the parameters and the resolution in describing the data and inverting for the parameters. In order to build practical inversion strategies, I suggest new parameters (called deviation parameters) for a new parameterization style in orthorhombic media. The novel parameters denoted ∈d, ƞd and δd are dimensionless and represent a measure of deviation between the vertical planes in orthorhombic anisotropy. The main feature of the deviation parameters consists of keeping the scattering of the vertical transversely isotropic (VTI) parameters stationary with azimuth. Using these scattering features, we can condition FWI to invert for the parameters which the data are sensitive to, at different stages, scales, and locations in the model. With this parameterization, the data are mainly sensitive to the scattering of 3 parameters (out of six that describe an acoustic orthorhombic medium): the horizontal velocity in the x1 direction, ∈1 which provides scattering mainly near

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

    KAUST Repository

    Djebbi, Ramzi; Alkhalifah, Tariq Ali

    2014-01-01

    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

  9. Experimental measurement of compressibility coefficients of synthetic sandstone in hydrostatic conditions

    International Nuclear Information System (INIS)

    Asaei, H; Moosavi, M

    2013-01-01

    For the characterization of the mechanical behavior of porous media in elastic conditions, the theory of poroelasticity is used. The number of poroelastic coefficients is greater in elastic conditions because of the complexity of porous media. The laboratory measurement of poroelastic coefficients needs a system that can control and measure the variables of poroelasticity. In this paper, experimental measurements of these coefficients are presented. Laboratory tests are performed using a system designed by the authors. Laboratory hydrostatic tests are performed on cylindrical samples in drained, pore pressure loading, undrained and dry conditions. Compressibilities (bulk and pore compressibility), effective stress and Skempton coefficients are measured by these tests. Samples are made of a composition (sand and cement) and are made by a compaction process synthetically. Calibration tests are performed for the setup to identify possible errors in the system and to correct the results of the main tests. This is done by performing similar compressibility tests at each stress level on a cylindrical steel sample (5.47 mm in diameter) with a longitudinal hole along it (hollow cylinder). A steel sample is used to assume an incompressible sample. The results of the tests are compared with the theory of poroelasticity and the obtained graphs and their errors are analyzed. This study shows that the results of the drained and pore pressure loading tests are compatible with poroelastic formulation, while the undrained results have errors because of extra fluid volume in the pore pressure system and calibration difficulties. (paper)

  10. Seismicity rate surge on faults after shut-in: poroelastic response to fluid injection

    Science.gov (United States)

    Chang, K. W.; Yoon, H.; Martinez, M. J.

    2017-12-01

    Subsurface energy activities such as geological CO2 storage and wastewater injection require injecting large amounts of fluid into the subsurface, which will alter the states of pore pressure and stress in the storage formation. One of the main issues for injection-induced seismicity is the post shut-in increases in the seismicity rate, often observed in the fluid-injection operation sites. The rate surge can be driven by the following mechanisms: (1) pore-pressure propagation into distant faults after shut-in and (2) poroelastic stressing caused by well operations, depending on fault geometry, hydraulic and mechanical properties of the formation, and injection history. We simulate the aerial view of the target reservoir intersected by strike-slip faults, in which injection-induced pressure buildup encounters the faults directly. We examine the poroelastic response of the faults to fluid injection and perform a series of sensitivity tests considering: (1) permeability of the fault zone, (2) locations and the number of faults with respect to the injection point, and (3) well operations with varying the injection rate. Our analysis of the Coulomb stress change suggests that the sealing fault confines pressure diffusion which stabilizes or weakens the nearby conductive fault depending on the injection location. We perform the sensitivity test by changing injection scenarios (time-dependent rates), while keeping the total amount of injected fluids. Sensitivity analysis shows that gradual reduction of the injection rate minimizes the Coulomb stress change and the least seismicity rates are predicted. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA-0003525.

  11. 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.

  12. Poroelastic Mechanical Effects of Hemicelluloses on Cellulosic Hydrogels under Compression

    Science.gov (United States)

    Lopez-Sanchez, Patricia; Cersosimo, Julie; Wang, Dongjie; Flanagan, Bernadine; Stokes, Jason R.; Gidley, Michael J.

    2015-01-01

    Hemicelluloses exhibit a range of interactions with cellulose, the mechanical consequences of which in plant cell walls are incompletely understood. We report the mechanical properties of cell wall analogues based on cellulose hydrogels to elucidate the contribution of xyloglucan or arabinoxylan as examples of two hemicelluloses displaying different interactions with cellulose. We subjected the hydrogels to mechanical pressures to emulate the compressive stresses experienced by cell walls in planta. Our results revealed that the presence of either hemicellulose increased the resistance to compression at fast strain rates. However, at slow strain rates, only xyloglucan increased composite strength. This behaviour could be explained considering the microstructure and the flow of water through the composites confirming their poroelastic nature. In contrast, small deformation oscillatory rheology showed that only xyloglucan decreased the elastic moduli. These results provide evidence for contrasting roles of different hemicelluloses in plant cell wall mechanics and man-made cellulose-based composite materials. PMID:25794048

  13. 3-D waveform tomography sensitivity kernels for anisotropic media

    KAUST Repository

    Djebbi, Ramzi; Alkhalifah, Tariq Ali

    2014-01-01

    The complications in anisotropic multi-parameter inversion lie in the trade-off between the different anisotropy parameters. We compute the tomographic waveform sensitivity kernels for a VTI acoustic medium perturbation as a tool to investigate

  14. Rubber and gel origami: visco- and poro-elastic behavior of folded structures

    Science.gov (United States)

    Evans, Arthur; Bende, Nakul; Na, Junhee; Hayward, Ryan; Santangelo, Christian

    2014-11-01

    The Japanese art of origami is rapidly becoming a platform for material design, as researchers develop systematic methods to exploit the purely geometric rules that allow paper to folded without stretching. Since any thin sheet couples mechanics strongly to geometry, origami provides a natural template for generating length-scale independent structures from a variety of different materials. In this talk I discuss some of the implications of using polymeric sheets and shells over many length scales to create folded materials with tunable shapes and properties. These implications include visco-elastic snap-through transitions and poro-elastically driven micro origami. In each case, mechanical response, dynamics, and reversible folding is tuned through a combination of geometry and constitutive properties, demonstrating the efficacy of using origami principles for designing functional materials.

  15. 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.

  16. General quantitative analysis of stress partitioning and boundary conditions in undrained biphasic porous media via a purely macroscopic and purely variational approach

    Science.gov (United States)

    Serpieri, Roberto; Travascio, Francesco

    2016-03-01

    In poroelasticity, the effective stress law relates the external stress applied to the medium to the macroscopic strain of the solid phase and the interstitial pressure of the fluid saturating the mixture. Such relationship has been formerly introduced by Terzaghi in form of a principle. To date, no poroelastic theory is capable of recovering a stress partitioning law in agreement with Terzaghi's postulated one in the absence of ad hoc constitutive assumptions on the medium. We recently proposed a variational macroscopic continuum description of two-phase poroelasticity to derive a general biphasic formulation at finite deformations, termed variational macroscopic theory of porous media (VMTPM). Such approach proceeds from the inclusion of the intrinsic volumetric strain among the kinematic descriptors aside to macroscopic displacements, and as a variational theory, uses the Hamilton least-action principle as the unique primitive concept of mechanics invoked to derive momentum balance equations. In a previous related work it was shown that, for the subclass of undrained problems, VMTPM predicts that stress is partitioned in the two phases in strict compliance with Terzaghi's law, irrespective of the microstructural and constitutive features of a given medium. In the present contribution, we further develop the linearized framework of VMTPM to arrive at a general operative formula that allows the quantitative determination of stress partitioning in a jacketed test over a generic isotropic biphasic specimen. This formula is quantitative and general, in that it relates the partial phase stresses to the externally applied stress as function of partitioning coefficients that are all derived by strictly following a purely variational and purely macroscopic approach, and in the absence of any specific hypothesis on the microstructural or constitutive features of a given medium. To achieve this result, the stiffness coefficients of the theory are derived by using

  17. Increase in transmission loss of single panels by addition of mass inclusions to a poro-elastic layer: Experimental investigation

    Science.gov (United States)

    Kidner, M. R. F.; Fuller, C. R.; Gardner, B.

    2006-06-01

    The insertion loss of standard acoustic blankets can be significantly improved at low frequencies by the addition of randomly placed mass inclusions to the poro-elastic layers. The improvement is much greater than that due to the mass effect alone. The mass inclusions act as resonant systems and so increase the structure impedance. This paper reports the results of experimental investigations into this phenomenon. Increases in insertion loss of 15 dB in the 100 Hz third octave band are reported.

  18. 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)

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

    International Nuclear Information System (INIS)

    Delorey, Andrew A.; Elst, Nicholas J. van der; Johnson, Paul Allan

    2016-01-01

    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. Lastly, 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.

  20. 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.

  1. A poroelastic reservoir model for predicting subsidence and mapping subsurface pressure fronts

    International Nuclear Information System (INIS)

    Du, J.; Olson, J.E.

    2001-01-01

    A forward model was constructed to numerically predict surface subsidence and reservoir compaction following the approach of Segall [Pure Appl. Phys. 139 (1992) 536]. A nucleus of poroelastic strain is numerically integrated over a rectangular prism assuming constant pressure change. This fundamental geometry allows a reservoir to be divided into many small cubic blocks in a manner similar to reservoir simulation. The subsidence and compaction effects of the pressure change throughout the reservoir are calculated by the superposition of results from each individual block. Using forward modeling, pressure boundary conditions can be acquired from pressure test data or reservoir simulation predictions. An inversion model also was developed that can track pressure fronts in a subsurface reservoir using surface displacements. The capability of the inversion model was demonstrated using synthetic examples of one-well and four-well cases with different layouts of surface observation locations. The impact of noise on the inversion result is also included

  2. 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.

  3. 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.

  4. Propagation of acoustic waves in a one-dimensional macroscopically inhomogeneous poroelastic material.

    Science.gov (United States)

    Gautier, G; Kelders, L; Groby, J P; Dazel, O; De Ryck, L; Leclaire, P

    2011-09-01

    Wave propagation in macroscopically inhomogeneous porous materials has received much attention in recent years. The wave equation, derived from the alternative formulation of Biot's theory of 1962, was reduced and solved recently in the case of rigid frame inhomogeneous porous materials. This paper focuses on the solution of the full wave equation in which the acoustic and the elastic properties of the poroelastic material vary in one-dimension. The reflection coefficient of a one-dimensional macroscopically inhomogeneous porous material on a rigid backing is obtained numerically using the state vector (or the so-called Stroh) formalism and Peano series. This coefficient can then be used to straightforwardly calculate the scattered field. To validate the method of resolution, results obtained by the present method are compared to those calculated by the classical transfer matrix method at both normal and oblique incidence and to experimental measurements at normal incidence for a known two-layers porous material, considered as a single inhomogeneous layer. Finally, discussion about the absorption coefficient for various inhomogeneity profiles gives further perspectives. © 2011 Acoustical Society of America

  5. 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

  6. Comparison of numerical dispersion for finite-difference algorithms in transversely isotropic media with a vertical symmetry axis

    International Nuclear Information System (INIS)

    Liang, Wen-Quan; Wang, Yan-Fei; Yang, Chang-Chun

    2015-01-01

    Numerical simulation of the wave equation is widely used to synthesize seismograms theoretically and is also the basis of the reverse time migration and full waveform inversion. For the finite difference methods, grid dispersion often exists because of the discretization of the time and the spatial derivatives in the wave equation. How to suppress the grid dispersion is therefore a key problem for finite difference (FD) approaches. The FD operators for the space derivatives are usually obtained in the space domain. However, the wave equations are discretized in the time and space directions simultaneously. So it would be better to design the FD operators in the time–space domain. We improved the time–space domain method for obtaining the FD operators in an acoustic vertically transversely isotropic (VTI) media so as to cover a much wider range of frequencies. Dispersion analysis and seismic numerical simulation demonstrate the effectiveness of the proposed method. (paper)

  7. Poroelastic Parameters of Peru Margin Sediments: Implications for Flow and Transport at Multiple Scales in the Marine Biosphere

    Science.gov (United States)

    Gettemy, G. L.; Cikoski, C.; Tobin, H. J.

    2004-12-01

    As part of a broader investigation of the deep marine subsurface environment, the first biosphere-focused drilling expedition, Leg 201, of the Ocean Drilling Program (ODP) occupied five unique sites in the Peru Margin (in a 1200 km2 region centered at 10 S, 80E). These sites represent the entire range of shallow biogeological conditions associated with this convergent margin:deep-water, mixed clay-pelagic sediments ocean-ward of the trench; slope-apron and prism toe sediments at the deformation front; and several distinct lithostratigraphic sequences on the continental shelf. Microbial enumeration and pore-water geochemistry results show that each particular site is both consistent and unique--consistent in terms of general biotic quantity and activity as predicted by energy flux and redox potential given the depositional environment and sedimentary record, but unique at key biogeological boundaries such as lithologic and/or physical property interfaces. This research addresses questions related to our understanding of how and why these boundaries form by looking at poroelastic and hydrologic parameters measured at multiple scales, from sub-millimeter to several centimeters. The issue of measurement scale, especially in regard to permeability and diffusivity characterization, is vital to interpreting observations of biologically-mediated diagenetic fronts (e.g., dolomitic lenses, depth- or time-varying barite fronts). These parameters are derived from (i) hydrologic and wave propagation experiments, (ii) SEM images, and (iii) shipboard split-core measurements, and structured in a modified Biot poroelasticity framework. This approach also allows quantification of the local heterogeneity of these parameters at the scale applicable to (and controlled by) microbial life; these results can then be used to formulate predictive models of the impact of biogeochemical processes. Ultimately, these models could then be used in interpretation of new remote-sensed data (e

  8. Effect of heavy tempering on microstructure and yield strength of 28CrMo48VTiB martensitic steel

    Science.gov (United States)

    Sun, Yu; Gu, Shunjie; Wang, Qian; Wang, Huibin; Wang, Qingfeng; Zhang, Fucheng

    2018-02-01

    The 28CrMo48VTiB martensitic steel for sulfide stress cracking (SSC) resistance oil country tubular goods (OCTG) of C110 grade was thermally processed through quenching at 890 °C and tempering at 600 °C-720 °C for 30-90 min. The microstructures of all samples were characterized using field emission scanning electron microscopy (FESEM), electron backscattering diffraction (EBSD), transmission electron microscopy (TEM) and x-ray diffractometry (XRD). Also, the tensile properties were measured. The results indicated that the yield strength (YS) decreased as both the tempering temperature and duration increased, due to the coarsening of martensitic packet/block/lath structures, the reduction of dislocation density, as well as the increase of both the volume fraction and average diameter of the precipitates. The martensitic lath width was the key microstructural parameter controlling the YS of this heavily-tempered martensitic steel, whereas the corresponding relationship was in accordance with the Langford-Cohen model. Furthermore, the martensitic structure boundary and the solid solution strengthening were the two most significant factors dominating the YS, in comparison with the dislocation and precipitation strengthening.

  9. Introduction to porous media micro-mechanics; Introduction a la micromecanique des milieux poreux

    Energy Technology Data Exchange (ETDEWEB)

    Dormieux, L.; Bourgeois, E.

    2002-07-01

    The study of porous materials can be considered at two different scales: the microscopic scale characterized by the size of the pores and by the domains occupied by the solid and the fluids, and the macroscopic scale which is controlled by the size of the structures under study (backfilling, foundations, dams, oil reservoirs or sedimentary basins). An alternative way, explored since about 30 years, consists in searching the formulation of macroscopic laws in the framework of a scale change approach. This is the point of view considered in this book which proposes a micro-mechanical approach of the modeling of porous environments based on various techniques of homogenization of the heterogenous materials with a random or periodical microstructure: 1 - macroscopic description of porous environments (space scales, skeleton deformation and kinematics, kinematics of fluid components, conservation laws, internal stresses); 2 - scale change techniques (representative elementary volume, averaging operation, application to conservation laws); 3 - Darcy transport (phenomenological approach of the Darcy law, Darcy law interpretation at the microscopic scale, fluid and solid phases interaction, flows inside a rigid porous environment, application); 4 - diffusive transport of a fluid component (solute transport equation, modeling of the macroscopic diffusive flux by scale change, application to pollutant diffusion); 5 - linear poro-elastic behaviour (first approach: empty sphere model, generalisation, estimation of poro-elastic characteristics); 6 - evolution problems in poro-elasticity (problem formulation, resolution, study of poro-elastic consolidation, tide response of an underwater massif, modeling of the formation of a syncline, study of the folding back of a sheet, numerical resolution of coupled problems, realization of a Scilab script); 7 - conclusion. (J.S.)

  10. Reflection moveout approximations for P-waves in a moderately anisotropic homogeneous tilted transverse isotropy layer

    Czech Academy of Sciences Publication Activity Database

    Pšenčík, Ivan; Farra, V.

    2017-01-01

    Roč. 82, č. 5 (2017), C175-C185 ISSN 0016-8033 R&D Projects: GA ČR(CZ) GA16-05237S Institutional support: RVO:67985530 Keywords : VTI media * velocity * seismic waves Subject RIV: DC - Siesmology, Volcanology, Earth Structure OBOR OECD: Volcanology Impact factor: 2.391, year: 2016

  11. The direct and inverse problems of an air-saturated poroelastic cylinder submitted to acoustic radiation

    Directory of Open Access Journals (Sweden)

    Erick Ogam

    2011-09-01

    Full Text Available A wave-fluid saturated poroelastic structure interaction model based on the modified Biot theory (MBT and plane-wave decomposition using orthogonal cylindrical functions is developed. The model is employed to recover from real data acquired in an anechoic chamber, the poromechanical properties of a soft cellular melamine cylinder submitted to an audible acoustic radiation. The inverse problem of acoustic diffraction is solved by constructing the objective functional given by the total square of the difference between predictions from the MBT interaction model and diffracted field data from experiment. The faculty of retrieval of the intrinsic poromechanical parameters from the diffracted acoustic fields, indicate that a wave initially propagating in a light fluid (air medium, is able to carry in the absence of mechanical excitation of the specimen, information on the macroscopic mechanical properties which depend on the microstructural and intrinsic properties of the solid phase.

  12. Waveform inversion for acoustic VTI media in frequency domain

    KAUST Repository

    Wu, Zedong; Alkhalifah, Tariq Ali

    2016-01-01

    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

  13. Anisotropic parameter inversion in VTI media using diffraction data

    KAUST Repository

    Waheed, Umair bin; Alkhalifah, Tariq Ali; Stovas, Alexey

    2013-01-01

    . 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

  14. Towards High-Performance Aqueous Sodium-Ion Batteries: Stabilizing the Solid/Liquid Interface for NASICON-Type Na2 VTi(PO4 )3 using Concentrated Electrolytes.

    Science.gov (United States)

    Zhang, Huang; Jeong, Sangsik; Qin, Bingsheng; Vieira Carvalho, Diogo; Buchholz, Daniel; Passerini, Stefano

    2018-02-22

    Aqueous Na-ion batteries may offer a solution to the cost and safety issues of high-energy batteries. However, substantial challenges remain in the development of electrode materials and electrolytes enabling high performance and long cycle life. Herein, we report the characterization of a symmetric Na-ion battery with a NASICON-type Na 2 VTi(PO 4 ) 3 electrode material in conventional aqueous and "water-in-salt" electrolytes. Extremely stable cycling performance for 1000 cycles at a high rate (20 C) is found with the highly concentrated aqueous electrolytes owing to the formation of a resistive but protective interphase between the electrode and electrolyte. These results provide important insight for the development of aqueous Na-ion batteries with stable long-term cycling performance for large-scale energy storage. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. 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.

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

    KAUST Repository

    Alkhalifah, Tariq Ali; Plessix, René É douard

    2014-01-01

    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.

  17. 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 ...

  18. Culturable heavy metal-resistant and plant growth promoting bacteria in V-Ti magnetite mine tailing soil from Panzhihua, China.

    Directory of Open Access Journals (Sweden)

    Xiumei Yu

    Full Text Available 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.

  19. Mechanics of adsorption-deformation coupling in porous media

    Science.gov (United States)

    Zhang, Yida

    2018-05-01

    This work extends Coussy's macroscale theory for porous materials interacting with adsorptive fluid mixtures. The solid-fluid interface is treated as an independent phase that obeys its own mass, momentum and energy balance laws. As a result, a surface strain energy term appears in the free energy balance equation of the solid phase, which further introduces the so-called adsorption stress in the constitutive equations of the porous skeleton. This establishes a fundamental link between the adsorption characteristics of the solid-fluid interface and the mechanical response of the porous media. The thermodynamic framework is quite general in that it recovers the coupled conduction laws, Gibbs isotherm and the Shuttleworth's equation for surface stress, and imposes no constraints on the magnitude of deformation and the functional form of the adsorption isotherms. A rich variety of coupling between adsorption and deformation is recovered as a result of combining different poroelastic models (isotropic vs. anisotropic, linear vs. nonlinear) and adsorption models (unary vs. mixture adsorption, uncoupled vs. stretch-dependent adsorption). These predictions are discussed against the backdrop of recent experimental data on coal swelling subjected to CO2 and CO2sbnd CH4 injections, showing the capability and versatility of the theory in capturing adsorption-induced deformation of porous materials.

  20. Attenuation of surface waves in porous media: Shock wave experiments and modelling

    NARCIS (Netherlands)

    Chao, G.E; Smeulders, D.M.J.; Dongen, van M.E.H.

    2005-01-01

    In this project we conduct experimental and numerical investigations on the attenuation mechanisms of surface waves in poroelastic materials. Viscous dissipation effects are modelled in the framework of Biot's theory. The experiments are performed using a shock tube technique. Quantitative agreement

  1. An introduction to linear poroelasticity

    OpenAIRE

    Merxhani, Andi

    2016-01-01

    This study is an introduction to the theory of three-dimensional consolidation. The point of departure in the description are the basic equations of elasticity (i.e. constitutive law, equations of equilibrium in terms of stresses, and the definition of strain), together with the principle of effective stress, and the law of Darcy for fluid flow in porous media. These equations, together with the principle of mass conservation, are the only premises used to derive a drained description of cons...

  2. Driving Simulator Development and Performance Study

    OpenAIRE

    Juto, Erik

    2010-01-01

    The driving simulator is a vital tool for much of the research performed at theSwedish National Road and Transport Institute (VTI). Currently VTI posses three driving simulators, two high fidelity simulators developed and constructed by VTI, and a medium fidelity simulator from the German company Dr.-Ing. Reiner Foerst GmbH. The two high fidelity simulators run the same simulation software, developed at VTI. The medium fidelity simulator runs a proprietary simulation software. At VTI there is...

  3. 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.

  4. Indentation of a free-falling lance penetrometer into a poroelastic seabed

    Science.gov (United States)

    Elsworth, Derek; Lee, Dae Sung

    2005-02-01

    A solution is developed for the build-up, steady and post-arrest dissipative pore fluid pressure fields that develop around a blunt penetrometer that self-embeds from freefall into the seabed. Arrest from freefall considers deceleration under undrained conditions in a purely cohesive soil, with constant shear strength with depth. The resulting decelerating velocity field is controlled by soil strength, geometric bearing capacity factors, and inertial components. At low impact velocities the embedment process is controlled by soil strength, and at high velocities by inertia. With the deceleration defined, a solution is evaluated for a point normal dislocation penetrating in a poroelastic medium with a prescribed decelerating velocity. Dynamic steady pressures, PD, develop relative to the penetrating tip geometry with their distribution conditioned by the non-dimensional penetration rate, UD, incorporating impacting penetration rate, consolidation coefficient and penetrometer radius, and the non-dimensional strength, ND, additionally incorporating undrained shear strength of the sediment. Pore pressures develop to a steady peak magnitude at the penetrometer tip, and drop as PD=1/xD with distance xD behind the tip and along the shaft. Peak induced pressure magnitudes may be correlated with sediment permeabilities, post-arrest dissipation rates may be correlated with consolidation coefficients, and depths of penetration may be correlated with shear strengths. Together, these records enable strength and transport parameters to be recovered from lance penetrometer data. Penetrometer data recorded off La Palma in the Canary Islands (J. Volcanol. Geotherm. Res. 2000; 101:253) are used to recover permeabilities and consolidation coefficients from peak pressure and dissipation response, respectively. Copyright

  5. Solid tumors are poroelastic solids with a chemo-mechanical feedback on growth.

    Science.gov (United States)

    Ambrosi, D; Pezzuto, S; Riccobelli, D; Stylianopoulos, T; Ciarletta, P

    2017-12-01

    The experimental evidence that a feedback exists between growth and stress in tumors poses challenging questions. First, the rheological properties (the "constitutive equations") of aggregates of malignant cells are still a matter of debate. Secondly, the feedback law (the "growth law") that relates stress and mitotic-apoptotic rate is far to be identified. We address these questions on the basis of a theoretical analysis of in vitro and in vivo experiments that involve the growth of tumor spheroids. We show that solid tumors exhibit several mechanical features of a poroelastic material, where the cellular component behaves like an elastic solid. When the solid component of the spheroid is loaded at the boundary, the cellular aggregate grows up to an asymptotic volume that depends on the exerted compression. Residual stress shows up when solid tumors are radially cut, highlighting a peculiar tensional pattern. By a novel numerical approach we correlate the measured opening angle and the underlying residual stress in a sphere. The features of the mechanobiological system can be explained in terms of a feedback of mechanics on the cell proliferation rate as modulated by the availability of nutrient, that is radially damped by the balance between diffusion and consumption. The volumetric growth profiles and the pattern of residual stress can be theoretically reproduced assuming a dependence of the target stress on the concentration of nutrient which is specific of the malignant tissue.

  6. 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 fi...

  7. 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

  8. Complex three dimensional modelling of porous media using high performance computing and multi-scale incompressible approach

    Science.gov (United States)

    Martin, R.; Orgogozo, L.; Noiriel, C. N.; Guibert, R.; Golfier, F.; Debenest, G.; Quintard, M.

    2013-05-01

    computed by sending batteries of codes in a mass production procedure. Some constraints can now be provided for poro-elastic imaging at the scale of reservoirs, for CO2 storage monitoring or geophysical exploration. 1. Golfier F. et al., Biofilms in porous media: Development of macroscopic transport equations va volume averaging with closure for local mass equilibrium conditions, Advances in Water Resources, 32, 463-485 (2009). 2. Orgogozo L. et al., Upscaling of transport processes in porous media with biofilms in non-equilibrium conditions, Advances in Water Resources, 33(5), 585-600 (2010). 3. Davit Y. et al., Modeling non-equilibrium mass transport in biologically reactive porous media, Advances in Water Resources, 33, 1075-1093, (2010). 4. Davit Y. et al., Imaging biofilm in porous media using X-ray computed micro-tomography, Journal of Microscopy, 242(1), 15-25 (2010). 5. Noiriel C. et al., Upscaling calcium carbonate precipitation rates from pore to continuum scale, Chemical Geology, 318-319, 60-74 (2012).

  9. Reflection and transmission characteristics of a layer obeying the two-pressure field poroelastic phenomenological model of Berryman and Wang.

    Science.gov (United States)

    Kachkouch, F; Franklin, H; Tinel, A

    2018-07-01

    The characteristics of the reflection and transmission by a fluid-loaded double porosity layer are studied. The medium obeys the two-pressure field poroelastic phenomenological model of Berryman and Wang. The open pore hydraulic conditions applied at the interfaces yield factorized expressions for the coefficients exhibiting on the one hand a separation allowing to distinguish between symmetrical and antisymmetrical motions and on the other hand the way each of the three dilatational waves associate with the shear wave. The numerical study done for a layer of Berea sandstone saturated by water shows clearly the role of each of the dilatational waves. There are peculiarities such as the absence of the fundamental antisymmetrical mode (zero order) and a singular behaviour of the symmetrical fundamental mode. The low frequency approximation for this latter is derived from the proposed formulas and compared with the numerical results. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Poroelastic Modeling as a Proof of Concept for Modular Representation of Coupled Geophysical Processes

    Science.gov (United States)

    Walker, R. L., II; Knepley, M.; Aminzadeh, F.

    2017-12-01

    We seek to use the tools provided by the Portable, Extensible Toolkit for Scientific Computation (PETSc) to represent a multiphysics problem in a form that decouples the element definition from the fully coupled equation through the use of pointwise functions that imitate the strong form of the governing equation. This allows allows individual physical processes to be expressed as independent kernels that may be then coupled with the existing finite element framework, PyLith, and capitalizes upon the flexibility offered by the solver, data management, and time stepping algorithms offered by PETSc. To demonstrate a characteristic example of coupled geophysical simulation devised in this manner, we present a model of a synthetic poroelastic environment, with and without the consideration of inertial effects, with fluid initially represented as a single phase. Matrix displacement and fluid pressure serve as the desired unknowns, with the option for various model parameters represented as dependent variables of the central unknowns. While independent of PyLith, this model also serves to showcase the adaptability of physics kernels for synthetic forward modeling. In addition, we seek to expand the base case to demonstrate the impact of modeling fluid as single phase compressible versus a single incompressible phase. As a goal, we also seek to include multiphase fluid modeling, as well as capillary effects.

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

    KAUST Repository

    Alkhalifah, Tariq Ali; Fomel, Sergey B.

    2009-01-01

    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

  12. Creep performance of welded pipe material made of 7CrMoVTiB10-10 (T/P24) steel

    Energy Technology Data Exchange (ETDEWEB)

    Rantala, Juhani; Auerkari, Pertti; Salonen, Jorma; Holmstroem, Stefan; Nevasmaa, Pekka [VTT Technical Research Centre of Finland, Espoo (Finland); Haekkilae, Juha [Foster Wheeler Energia, Varkaus (Finland)

    2010-07-01

    The creep strength of welded low-alloy ferritic steels is typically somewhat lower than that for parent metal, but this is generally due to an inherent weakness of the heat affected zone and accounted for in the common design codes. However, the parent material strength is much higher in certain modern low alloy steels such as 7CrMoVTiB10-10 (P24), and then it can be a significant challenge to develop weld metals (welding consumables) to match this strength. Acceptable weld performance has been previously demonstrated for thin-wall tubes where sufficient mixing with the base material can occur. The objective of this work was to achieve satisfactory properties for a thick-wall welded pipe by using an Nb-modified consumable to avoid weld metal weakening due to arc losses of Ti of a consumable composition approximately matching the base material. A considerable improvement was indeed noted in comparison with earlier experience using matching electrode composition. All short term test results for weld qualification showed acceptable properties, the cross-weld creep strength remain very close to the -20% band from the parent metal creep strength. However, creep testing at lowest stress levels approaching those expected in service resulted in weld metal failure. Although a clear improvement is evident from the previous generation of weld metals, there appears to be some further scope of development of the welding consumables, to improve the long term creep ductility of the welded joints particularly when applying production-like welding parameters. (orig.)

  13. 'Perfectly disordered' medium as a model for the description of micro-inhomogeneous mixtures

    International Nuclear Information System (INIS)

    Levin, V M; Markov, M G; Alvarez-Tostado, J M

    2004-01-01

    The correct description of the macroscopic (overall) physical properties of micro-inhomogeneous (composite) materials by micro-mechanics methods (the self-consistent schemes, for example) requires information about the microstructure and texture of such materials. Often, such information (of shapes inhomogeneities and peculiarities of their spatial distribution) is not available. In this paper, we suggest a method of calculation of the characteristics of micro-inhomogeneous materials that could be applied to a wide class of isotropic materials. This method assumes the absence of a closed order in the material microstructure (a 'perfectly disordered' (PD) medium). We used the PD approximation to predict the effective thermo- and poroelastic, electric and thermal properties of micro-inhomogeneous media. The expressions for the effective characteristics obtained by this method are always inside of the Hashin-Shtrikman universal bounds. For a two-phase material with fluid component, the effective bulk module satisfies Gassmann's relation for fluid-filled porous media and generalizes such a relation to inhomogeneous thermoelastic and poroelastic media. A comparison of the theoretical results with available experimental data shows a satisfactory coincidence even in the case of high contrast of the component properties. The simplicity of the numerical realization of the method makes it attractive for applications in the absence of detailed information about the material's microstructure

  14. Halting Land Subsidence in Tucson, Arizona: Examining the Poroelastic Response to Artificial Recharge

    Science.gov (United States)

    Miller, M. M.; Shirzaei, M.; Argus, D. F.

    2017-12-01

    Overexploitation of groundwater results in stressed aquifer systems and surface deformation in the form of land subsidence. Differential land subsidence can lead to earth fissures, which threaten buildings and infrastructure. Therefore, careful water management is necessary to ensure aquifer resources are withdrawn and replenished at a sustainable yield to preserve supplies and minimize surface deformation. Tucson, Arizona is a semi-arid desert city that is reliant on a semi-confined alluvial aquifer system for much of the water supply. To understand the poroelastic response of the aquifer system over time, we analyze data from wells equipped with extensometers, InSAR time series, and GPS. From 1990-2005, compaction of fine-grained, aquitard material is measured up to 8.5 mm/yr at well sites equipped with extensometers. This induces permanent aquifer storage volume losses up to 4.1%. Yet, interferograms from Envisat and RadarSAT-2 C-band satellites, which yield multitemporal deformation maps at high resolution, reveal that subsidence remarkably slows by the late 2000s and nearly halts by 2015. We infer this deceleration corresponds to heightened artificial recharge efforts to bank Colorado River water delivered via canal. After groundwater levels recover, residual compaction continues for just a 6.6-year interval, which suggests a high value for vertical hydraulic conductivity up to 9.8 x10-4 m/day. Successful water management and conservation plans help the city preserve existing and replenish depleted groundwater reserves, decelerate land subsidence, and likely reduce the risks associated with earth fissuring.

  15. Immiscible two-phase fluid flows in deformable porous media

    Science.gov (United States)

    Lo, Wei-Cheng; Sposito, Garrison; Majer, Ernest

    Macroscopic differential equations of mass and momentum balance for two immiscible fluids in a deformable porous medium are derived in an Eulerian framework using the continuum theory of mixtures. After inclusion of constitutive relationships, the resulting momentum balance equations feature terms characterizing the coupling among the fluid phases and the solid matrix caused by their relative accelerations. These terms, which imply a number of interesting phenomena, do not appear in current hydrologic models of subsurface multiphase flow. Our equations of momentum balance are shown to reduce to the Berryman-Thigpen-Chen model of bulk elastic wave propagation through unsaturated porous media after simplification (e.g., isothermal conditions, neglect of gravity, etc.) and under the assumption of constant volume fractions and material densities. When specialized to the case of a porous medium containing a single fluid and an elastic solid, our momentum balance equations reduce to the well-known Biot model of poroelasticity. We also show that mass balance alone is sufficient to derive the Biot model stress-strain relations, provided that a closure condition for porosity change suggested by de la Cruz and Spanos is invoked. Finally, a relation between elastic parameters and inertial coupling coefficients is derived that permits the partial differential equations of the Biot model to be decoupled into a telegraph equation and a wave equation whose respective dependent variables are two different linear combinations of the dilatations of the solid and the fluid.

  16. Low-frequency asymptotic analysis of seismic reflection from afluid-saturated medium

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-04-14

    Reflection of a seismic wave from a plane interface betweentwo elastic media does not depend on the frequency. If one of the mediais poroelastic and fluid-saturated, then the reflection becomesfrequency-dependent. This paper presents a low-frequency asymptoticformula for the reflection of seismic plane p-wave from a fluid-saturatedporous medium. The obtained asymptotic scaling of the frequency-dependentcomponent of the reflection coefficient shows that it is asymptoticallyproportional to the square root of the product of the reservoir fluidmobility and the frequency of the signal. The dependence of this scalingon the dynamic Darcy's law relaxation time is investigated as well.Derivation of the main equations of the theory of poroelasticity from thedynamic filtration theory reveals that this relaxation time isproportional to Biot's tortuosity parameter.

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

    KAUST Repository

    Calo, Victor M.; Iliev, Dimitar; Iliev, Oleg; Kirsch, Ralf; Lakdawala, Zahra; Printsypar, Galina

    2015-01-01

    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

  18. 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.

  19. Saturated poroelastic actuators generated by topology optimization

    DEFF Research Database (Denmark)

    Andreasen, Casper Schousboe; Sigmund, Ole

    2011-01-01

    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.......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...

  20. A Poroelasticity Theory Approach to Study the Mechanisms Leading to Elevated Interstitial Fluid Pressure in Solid Tumours.

    Science.gov (United States)

    Burazin, Andrijana; Drapaca, Corina S; Tenti, Giuseppe; Sivaloganathan, Siv

    2018-05-01

    Although the mechanisms responsible for elevated interstitial fluid pressure (IFP) in tumours remain obscure, it seems clear that high IFP represents a barrier to drug delivery (since the resulting adverse pressure gradient implies a reduction in the driving force for transvascular exchange of both fluid and macromolecules). R. Jain and co-workers studied this problem, and although the conclusions drawn from their idealized mathematical models offered useful insights into the causes of elevated IFP, they by no means gave a definitive explanation for this phenomenon. In this paper, we use poroelasticity theory to also develop a macroscopic mathematical model to describe the time evolution of a solid tumour, but focus our attention on the mechanisms responsible for the rise of the IFP, from that for a healthy interstitium to that measured in malignant tumours. In particular, we discuss a number of possible time scales suggested by our mathematical model and propose a tumour-dependent time scale that leads to results in agreement with experimental observations. We apply our mathematical model to simulate the effect of "vascular normalization" (as proposed by Jain in Nat Med 7:987-989, 2001) on the IFP profile and discuss and contrast our conclusions with those of previous work in the literature.

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

    KAUST Repository

    Alkhalifah, Tariq Ali; Fomel, S.

    2011-01-01

    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. 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.

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

    KAUST Repository

    Oh, Juwon; Alkhalifah, Tariq Ali; Min, Dong-Joo

    2015-01-01

    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

  4. Acoustic anisotropic wavefields through perturbation theory

    KAUST Repository

    Alkhalifah, Tariq Ali

    2013-09-01

    Solving the anisotropic acoustic wave equation numerically using finite-difference methods introduces many problems and media restriction requirements, and it rarely contributes to the ability to resolve the anisotropy parameters. Among these restrictions are the inability to handle media with η<0 and the presence of shear-wave artifacts in the solution. Both limitations do not exist in the solution of the elliptical anisotropic acoustic wave equation. Using perturbation theory in developing the solution of the anisotropic acoustic wave equation allows direct access to the desired limitation-free solutions, that is, solutions perturbed from the elliptical anisotropic background medium. It also provides a platform for parameter estimation because of the ability to isolate the wavefield dependency on the perturbed anisotropy parameters. As a result, I derive partial differential equations that relate changes in the wavefield to perturbations in the anisotropy parameters. The solutions of the perturbation equations represented the coefficients of a Taylor-series-type expansion of the wavefield as a function of the perturbed parameter, which is in this case η or the tilt of the symmetry axis. The expansion with respect to the symmetry axis allows use of an acoustic transversely isotropic media with a vertical symmetry axis (VTI) kernel to estimate the background wavefield and the corresponding perturbation coefficients. The VTI extrapolation kernel is about one-fourth the cost of the transversely isotropic model with a tilt in the symmetry axis kernel. Thus, for a small symmetry axis tilt, the cost of migration using a first-order expansion can be reduced. The effectiveness of the approach was demonstrated on the Marmousi model.

  5. The effect of external mean flow on sound transmission through double-walled cylindrical shells lined with poroelastic material

    Science.gov (United States)

    Zhou, Jie; Bhaskar, Atul; Zhang, Xin

    2014-03-01

    Sound transmission through a system of double shells, lined with poroelastic material in the presence of external mean flow, is studied. The porous material is modeled as an equivalent fluid because shear wave contributions are known to be insignificant. This is achieved by accounting for the energetically most dominant wave types in the calculations. The transmission characteristics of the sandwich construction are presented for different incidence angles and Mach numbers over a wide frequency range. It is noted that the transmission loss exhibits three dips on the frequency axis as opposed to flat panels where there are only two such frequencies—results are discussed in the light of these observations. Flow is shown to decrease the transmission loss below the ring frequency, but increase this above the ring frequency due to the negative stiffness and the damping effect added by the flow. In the absence of external mean flow, porous material provides superior insulation for most part of the frequency band of interest. However, in the presence of external flow, this is true only below the ring frequency—above this frequency, the presence of air gap in sandwich constructions is the dominant factor that determines the acoustic performance. In the absence of external flow, an air gap always improves sound insulation.

  6. 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…

  7. 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.

  8. An asymptotic model of seismic reflection from a permeable layer

    Energy Technology Data Exchange (ETDEWEB)

    Silin, D.; Goloshubin, G.

    2009-10-15

    Analysis of compression wave propagation in a poroelastic medium predicts a peak of reflection from a high-permeability layer in the low-frequency end of the spectrum. An explicit formula expresses the resonant frequency through the elastic moduli of the solid skeleton, the permeability of the reservoir rock, the fluid viscosity and compressibility, and the reservoir thickness. This result is obtained through a low-frequency asymptotic analysis of Biot's model of poroelasticity. A review of the derivation of the main equations from the Hooke's law, momentum and mass balance equations, and Darcy's law suggests an alternative new physical interpretation of some coefficients of the classical poroelasticity. The velocity of wave propagation, the attenuation factor, and the wave number, are expressed in the form of power series with respect to a small dimensionless parameter. The absolute value of this parameter is equal to the product of the kinematic reservoir fluid mobility and the wave frequency. Retaining only the leading terms of the series leads to explicit and relatively simple expressions for the reflection and transmission coefficients for a planar wave crossing an interface between two permeable media, as well as wave reflection from a thin highly-permeable layer (a lens). Practical applications of the obtained asymptotic formulae are seismic modeling, inversion, and at-tribute analysis.

  9. A low-frequency asymptotic model of seismic reflection from a high-permeability layer

    Energy Technology Data Exchange (ETDEWEB)

    Silin, Dmitriy; Goloshubin, Gennady

    2009-03-01

    Analysis of compression wave propagation through a high-permeability layer in a homogeneous poroelastic medium predicts a peak of reflection in the low-frequency end of the spectrum. An explicit formula expresses the resonant frequency through the elastic moduli of the solid skeleton, the permeability of the reservoir rock, the fluid viscosity and compressibility, and the reservoir thickness. This result is obtained through a low-frequency asymptotic analysis of the Biot's model of poroelasticity. A new physical interpretation of some coefficients of the classical poroelasticity is a result of the derivation of the main equations from the Hooke's law, momentum and mass balance equations, and the Darcy's law. The velocity of wave propagation, the attenuation factor, and the wave number, are expressed in the form of power series with respect to a small dimensionless parameter. The latter is equal to the product of the kinematic reservoir fluid mobility, an imaginary unit, and the frequency of the signal. Retaining only the leading terms of the series leads to explicit and relatively simple expressions for the reflection and transmission coefficients for a planar wave crossing an interface between two permeable media, as well as wave reflection from a thin highly-permeable layer (a lens). The practical implications of the theory developed here are seismic modeling, inversion, and attribute analysis.

  10. Diagnostic value of coustic radiation force impulse for BI-RADS category 4 breast lesions of different sizes.

    Science.gov (United States)

    Wu, Rong

    2018-04-14

    To determine the diagnostic value of combined conventional ultrasound (US) and acoustic radiation force impulse (ARFI) imaging for the differential diagnosis of BI-RADS category 4 breast lesions of different sizes. From April 2013 to January 2015, 283 patients (with a total of 292 breast lesions) who underwent US and ARFI examination were included in this retrospective study. The SWV for the lesion and adjacent normal breast tissue were measured and the SWV ratio was calculated. VTI grade was also assessed. The lesions were separated into three groups on the basis of size, and two combinations of ARFI parameters (SWV + VTI and SWV ratio + VTI) were applied to reassess the BI-RADS categories. Diagnoses were confirmed by pathological examination after biopsy or surgery. ROC analysis was performed to assess the diagnostic efficiency of each method. The Z test was used to compare the difference between AUC of the two methods. Significant improvement was seen in the diagnostic performance of US with the use of the ARFI parameters SWV + VTI (77/179 [43.0%] of BI-RADS category 4A breast lesions were downgraded) and SWV ratio + VTI (64/179 [35.8%] of BI-RADS category 4A breast lesions were downgraded, including two malignant cases that were misdiagnosed as benign) (P BI-RADS category 4 breast lesions. The combination of SWV ratio + VTI can improve BI-RADS classification of small lesions (<10 mm size).

  11. 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…

  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. Landbaserade godstransporter, klimat och styrmedel : underlagsrapporter 1-10

    OpenAIRE

    Carlén, Björn; Hultkrantz, Lars; Liu, Xing; Lunander, Anders; Mandell, Svante; Mellin, Anna; Nilsson, Jan-Eric; Pyddoke, Roger; Sorkina, Edith; Vierth, Inge

    2014-01-01

    VTI notat 28-2014 innehåller de tio underlagsrapporter som ligger till grund för VTI rapport 831: ”Landbaserade godstransporter, klimat och styrmedel – Sammanfattande rapport”. I VTI rapport 831 diskuterar forskarna flera dimensioner av hur växthusgaserna från godstransportsektorn ska kunna minskas, till exempel med hjälp av så kallade Gröna korridorer. Vidare diskuteras hur man ska se på de klimatpolitiska konsekvenserna av överflyttning från väg till järnväg eller elektrifierade fordon på v...

  14. Safety in online media – freedom of the media; safety of media actors and media education

    OpenAIRE

    Moeller, Ch

    2013-01-01

    In this paper, prepared for the international conference ‘Mass Media – Society – Education: Media Safety Problems’ at the Chelyabinsk State University’s Department for Journalism and Media Education from September 30 – October 3, 2013, I would like to address three dimensions of media safety and security in online media.

  15. Media Literacy in Times of Media Divides

    Directory of Open Access Journals (Sweden)

    Kaja Žuran

    2013-12-01

    Full Text Available We live in a post-modern society, an information society, a society based around knowledge and participation, and above all in a media society. In a media culture where media holds a dominant position, we cannot overlook the emerging idea of a ‘media divide’ within the frame of media education, media literate individuals and the expansion of the traditional concept of media literacy. Firstly, we are in an era of technological revolution, and it is time to consider the meaning and function of media and how we experience it in our everyday life. Secondly, as a society we are subject to intense media invasion and we all need to learn how to use it to our benefit and apply a critical and autonomous perspective towards selecting media content. Otherwise the media divide between the media literate and illiterate will widen; but is there even a chance to overcome the supposed divide between those who are formally media educated and those who are not?

  16. [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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Goodwin, Laurel B.; Boutt David F.

    2010-02-18

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

  18. On the role of density and attenuation in three-dimensional multiparameter viscoacoustic VTI frequency-domain FWI: an OBC case study from the North Sea

    Science.gov (United States)

    Operto, S.; Miniussi, A.

    2018-06-01

    3-D frequency-domain full waveform inversion (FWI) is applied on North Sea wide-azimuth ocean-bottom cable data at low frequencies (≤10 Hz) to jointly update vertical wave speed, density and quality factor Q in the viscoacoustic VTI approximation. We assess whether density and Q should be viewed as proxy to absorb artefacts resulting from approximate wave physics or are valuable for interpretation in the presence of soft sediments and gas cloud. FWI is performed in the frequency domain to account for attenuation easily. Multiparameter frequency-domain FWI is efficiently performed with a few discrete frequencies following a multiscale frequency continuation. However, grouping a few frequencies during each multiscale step is necessary to mitigate acquisition footprint and match dispersive shallow guided waves. Q and density absorb a significant part of the acquisition footprint hence cleaning the velocity model from this pollution. Low Q perturbations correlate with low-velocity zones associated with soft sediments and gas cloud. However, the amplitudes of the Q perturbations show significant variations when the inversion tuning is modified. This dispersion in the Q reconstructions is however not passed on the velocity parameter suggesting that cross-talks between first-order kinematic and second-order dynamic parameters are limited. The density model shows a good match with a well log at shallow depths. Moreover, the impedance built a posteriori from the FWI velocity and density models shows a well-focused image with however local differences with the velocity model near the sea bed where density might have absorbed elastic effects. The FWI models are finally assessed against time-domain synthetic seismogram modelling performed with the same frequency-domain modelling engine used for FWI.

  19. 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.

  20. Control of the nitrogen concentration in liquid lithium by the hot trap method

    International Nuclear Information System (INIS)

    Sakurai, Toshiharu; Yoneoka, Toshiaki; Tanaka, Satoru; Suzuki, Akihiro; Muroga, Takeo

    2002-01-01

    The nitrogen concentration in liquid lithium was controlled by the hot-trap method. Titanium, vanadium and a V-Ti alloy were used as nitrogen gettering materials. Gettering experiments were conducted at 673, 773 and 823 K for 0.4-2.8 Ms. After immersion, the nitrogen concentration increased in titanium and V-Ti were tested at 823 K. Especially the nitrogen gettering effect by the V-10at.%Ti alloy was found to be large. Nitrogen was considered to exist mainly as solid solution in the V-10at.%Ti alloy. The decrease of the nitrogen concentration in liquid lithium by the V-Ti gettering was also confirmed

  1. 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? ...

  2. 3-D waveform tomography sensitivity kernels for anisotropic media

    KAUST Repository

    Djebbi, Ramzi

    2014-01-01

    The complications in anisotropic multi-parameter inversion lie in the trade-off between the different anisotropy parameters. We compute the tomographic waveform sensitivity kernels for a VTI acoustic medium perturbation as a tool to investigate this ambiguity between the different parameters. We use dynamic ray tracing to efficiently handle the expensive computational cost for 3-D anisotropic models. Ray tracing provides also the ray direction information necessary for conditioning the sensitivity kernels to handle anisotropy. The NMO velocity and η parameter kernels showed a maximum sensitivity for diving waves which results in a relevant choice of those parameters in wave equation tomography. The δ parameter kernel showed zero sensitivity; therefore it can serve as a secondary parameter to fit the amplitude in the acoustic anisotropic inversion. Considering the limited penetration depth of diving waves, migration velocity analysis based kernels are introduced to fix the depth ambiguity with reflections and compute sensitivity maps in the deeper parts of the model.

  3. SOCIAL MEDIA

    Science.gov (United States)

    RESPONSIBILITY CENTCOM COALITION MEDIA SOCIAL MEDIA NEWS ARTICLES PRESS RELEASES IMAGERY VIDEOS TRANSCRIPTS VISITORS AND PERSONNEL FAMILY CENTER FAMILY READINESS CENTCOM WEBMAIL SOCIAL MEDIA SECURITY ACCOUNTABILITY HomeMEDIASOCIAL MEDIA Social Media CENTCOM'S ENGLISH SOCIAL MEDIA ACCOUNTS There are many U.S. military commands

  4. 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.

  5. Media education and media influence on youth

    OpenAIRE

    LILÁK, Karel

    2011-01-01

    Bachelor´s work is focused on the questions of the medial education and the medias themselves. This work also investigate with the influence of the action of medias to the students of apprenticeship. The first part of the theoretical work has generally explains what is media education, what is its significance for society and for the benefit of education in school. They are given functions, types and objectives of media education and communications capabilities via the media. The second part ...

  6. New pulmonary vein Doppler echocardiographic index predicts significant interatrial shunting in secundum atrial septal defect.

    Science.gov (United States)

    Lam, Yat-Yin; Fang, Fang; Yip, Gabriel Wai-Kwok; Li, Zhi-An; Yang, Ya; Yu, Cheuk-Man

    2012-09-20

    The relation between pulmonary venous flow (PVF) pattern and degree of left-to-right interatrial shunting (IAS) in patients with secundum atrial septal defect (ASD) is unknown. Fifty consecutive ASD patients (14 males, 36 ± 17 years) received transthoracic echocardiography (TTE) before and 1 day after transcatheter closure and their results were compared to 40 controls. The ratio of pulmonary-to-systemic flows (Qp/Qs) was assessed by TTE and invasive oximetry. Pre-closure PV systolic (PVs), diastolic (PVd) velocities and velocity-time integral (PV-VTI) increased, time from onset of ECG Q-wave to the peak PV diastolic wave (Q-PVd) shortened and atrial reversal (PVar) velocity significantly decreased as compared to normals. These findings normalized after closure. Patients with large IAS (defined as invasive Qp/Qs ≥ 2) had higher PVs, PVd and PV-VTI, shorter Q-PVd but lower PVar (all pIAS. Invasive Qp/Qs ratios correlated with PVs, PVd, PV-VTI, Q-PVd and TTE-derived Qp/Qs ratios, ASD sizes and RV end-diastolic dimensions (all pIAS after multivariate analysis. The corresponding sensitivity, specificity and AUC were 89%, 82% and 0.90 respectively for a PV-VTI of 30 cm (pIAS have distinguishable PVF features. Doppler evaluation of PV-VTI is a novel additional tool for assessing the magnitude of shunting in these patients non-invasively. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  7. 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.

  8. Komunikasi Krisis di Era New Media dan Social Media

    OpenAIRE

    Prastya, Narayana Mahendra

    2016-01-01

    New media and social media have changed the practice of public relations. One area that changed is crisis communication. Because of these new technologies, crisis can be more complex. The pace of information, the uncertainty, and the rumors, are increasing. Public relations practitioners should include the new media and social media use in their crisis communication plan. Before doing that, public relations practitioners should change their mindset about social media and new media. The first ...

  9. On the role of density and attenuation in 3D multi-parameter visco-acoustic VTI frequency-domain FWI: an OBC case study from the North Sea

    Science.gov (United States)

    Operto, S.; Miniussi, A.

    2018-03-01

    Three-dimensional frequency-domain full waveform inversion (FWI) is applied on North Sea wide-azimuth ocean-bottom cable data at low frequencies (≤ 10 Hz) to jointly update vertical wavespeed, density and quality factor Q in the visco-acoustic VTI approximation. We assess whether density and Q should be viewed as proxy to absorb artefacts resulting from approximate wave physics or are valuable for interpretation in presence of saturated sediments and gas. FWI is performed in the frequency domain to account for attenuation easily. Multi-parameter frequency-domain FWI is efficiently performed with a few discrete frequencies following a multi-scale frequency continuation. However, grouping a few frequencies during each multi-scale step is necessary to mitigate acquisition footprint and match dispersive shallow guided waves. Q and density absorb a significant part of the acquisition footprint hence cleaning the velocity model from this pollution. Low Q perturbations correlate with low velocity zones associated with soft sediments and gas cloud. However, the amplitudes of the Q perturbations show significant variations when the inversion tuning is modified. This dispersion in the Q reconstructions is however not passed on the velocity parameter suggesting that cross-talks between first-order kinematic and second-order dynamic parameters are limited. The density model shows a good match with a well log at shallow depths. Moreover, the impedance built a posteriori from the FWI velocity and density models shows a well-focused image with however local differences with the velocity model near the sea bed where density might have absorbed elastic effects. The FWI models are finally assessed against time-domain synthetic seismogram modelling performed with the same frequency-domain modelling engine used for FWI.

  10. 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.

  11. Sensitive Media

    Directory of Open Access Journals (Sweden)

    Malinowska Anna

    2017-12-01

    Full Text Available The paper engages with what we refer to as “sensitive media,” a concept associated with developments in the overall media environment, our relationships with media devices, and the quality of the media themselves. Those developments point to the increasing emotionality of the media world and its infrastructures. Mapping the trajectories of technological development and impact that the newer media exert on human condition, our analysis touches upon various forms of emergent affect, emotion, and feeling in order to trace the histories and motivations of the sensitization of “the media things” as well as the redefinition of our affective and emotional experiences through technologies that themselves “feel.”

  12. Social Media Sites

    Science.gov (United States)

    Media Sites Site Registration Contact Us Search AF.mil: Home > AF Sites > Social Media Sites Social Media Welcome to the Air Force social media directory! The directory is a one-stop shop of official Air Force social media pages across various social media sites. Social media is all about

  13. 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. .

  14. 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.

  15. 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...

  16. 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...

  17. Inhibitor effect on corrosion of titanium alloys in muriatic solutions of titanium-magnesium production

    International Nuclear Information System (INIS)

    Dobrunov, Yu.V.; Volynskij, V.V.; Kolobov, G.A.; Kuznetsov, S.I.

    1977-01-01

    Corrosion tests of titanium alloys VTI-0, OT4, VT5-1 and steel Kh18N1OT in 10% and 18% HCl with additions of carnallite at 40 deg C have been carried out. It has been established that titanium alloys in 10% and 18% HCl containing 5 and 10% carnallite are sufficiently corrosion resistant in the presence of 0.1-1% FeCl or HNO 3 and can be used for manufacturing the equipment of recirculation gas scrubbers. Steel Kh18N10T is unstable in all the media tested. It is subjected to intensive pitting. Specimens of steel Kh18N10T have also revealed edge cracking

  18. 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.

  19. 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....

  20. 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....

  1. New media technologies and mass media reform processes

    Directory of Open Access Journals (Sweden)

    Tomić Boban

    2017-01-01

    Full Text Available This paper reviews and assesses the chances for survival and development of the media in Serbia and ib the region, from the perspective of new information and communication technologies (ICT applied in media business. In the paper theoretical method is used and harmonized with the needs of describing the problems and the observed processes and phenomena, as well as empirical method which is used for collecting and interpreting concrete facts and data on the observed processes and phenomena. The starting point lies in the fact that modern media is definitely, more and more, dependent on new technologies. A part of the new technologies is used in the process of collecting, selecting and editing media content, while the other part of the technology is used in the process of dissemination and propulsion of media content to the mass audience, and also in the feedback function as well. The technology revolution, which we describe, started with mp3, jpg and avi files, and continues with internet broadcasting, social networks, cloud technologies and new digital platforms which are used by today's media for distribution of media content. The particularity of the media in the region lies in the fact that they operating in the societes with delay of political and economic transition, so all the productive resources of society, due to this backlog, are slower adapted to the new conditions of business in the digital era. The consequences that have arisen from such dynamics of development make many media in Serbia and the region quite dysfunctional, especially those who were exposed during this transition to long-standing legal, economic and program crises. That is why most of the existing media in Serbia, especially small ones, are unprepared for modernization and they are not ready for re-modeling in accordance with the new technological circumstances.

  2. [Media for 21st century--towards human communication media].

    Science.gov (United States)

    Harashima, H

    2000-05-01

    Today, with the approach of the 21st century, attention is focused on multi-media communications combining computer, visual and audio technologies. This article discusses the communication media target and the technological problems constituting the nucleus of multi-media. The communication media is becoming an environment from which no one can escape. Since the media has such a great power, what is needed now is not to predict the future technologies, but to estimate the future world and take to responsibility for future environments.

  3. Media Ecology

    Directory of Open Access Journals (Sweden)

    Marina Ašković

    2015-05-01

    Full Text Available Does the trend in which electronic media are gradually becoming extension of human body have to move towards full enslavement of a human and his personality, or the same human will unpredictably, with the aid of his personal media literacy, exit the whirls of media and technological censorships? Personality crisis is closely related to the crisis of language no matter how contradicted to global ideology of transnational transhumanism it may seem. Considering the fact that recent media presentations of the world are based on commercialization of environmentalism, philosophical and aesthetic thought appears as an important subject of ecology. As media mediates, the scenery of civilized living increasingly becomes more appealing even though it derives from commercial and political background. Consequently, the future of humanity depends by large on the philosophy of media. Media have to truly ecologise returning the humanum to its essence making it into the extension of the natural world.

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

    Science.gov (United States)

    Fedorov, Alexander; Levitskaya, Anastasia

    2017-01-01

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

  5. 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…

  6. SOCIAL MEDIA SECURITY

    Science.gov (United States)

    RESPONSIBILITY CENTCOM COALITION MEDIA SOCIAL MEDIA NEWS ARTICLES PRESS RELEASES IMAGERY VIDEOS TRANSCRIPTS VISITORS AND PERSONNEL FAMILY CENTER FAMILY READINESS CENTCOM WEBMAIL SOCIAL MEDIA SECURITY ACCOUNTABILITY HomeVISITORS AND PERSONNELSOCIAL MEDIA SECURITY FAQ on Security for Social Media Due to the widespread use of

  7. ANALISIS CATEGORY ADVERTISING EXPENDITURE DAN CONSUMER MEDIA HABIT DI MEDIA TELEVISI DAN MEDIA CETAK

    Directory of Open Access Journals (Sweden)

    Zifwen Zifwen

    2011-08-01

    Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 The purpose of the study is to identify the category of advertising expenditure and media habit on media advertising, especially on television and print ad such as newspapers, magazines and tabloids. The Data were collected  from Nielsen Media Research (NMR data base from a number of cities in Indonesia, such as Jakarta,Surabaya, Bandung, Semarang, Surabaya, Yogyakarta, Bali, Medan,Palembang and Makassar. There are three different type of data used to acquire the secondary data for the study: (1  Telescope (data collected for rating analysis January 1st, 2005 to March 31st, 2005, (2 Print scope (data collected from the readership of magazines, tabloids and newspaper January 1st, 2004 to December 31st, 2004 and (3 Ad quest (data collected from advertising expenditure for all categories. The data were collected, calculated and analyzed from January 1st, 2002 to December 31st, 2004. The purpose of the study is to uncover the trend of advertising budget from all categories on the television and print ads, in order to describe the consumption tendency of the people within advertising media. Index analysis and Biplot were used to analyze the data. Based on the result of advertising expenditure analysis of data, showing that all categories were completely different in the utilization of the media for advertisement. Some categories used mix media to support their campaign and others used a single media. Characteristic of the categories were strongly involved in the decision making in way of choosing and using the advertising media. The result of consumer media analysis found that the people habit were completely different and unique in media consumption. Different of age, sex and social economic status can create a different habit in term of hobbies and desire within the channel, programme, newspaper, magazines and the tabloids. Finally, to create an effective and efficient advertising activity

  8. 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…

  9. 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.

  10. Locative media

    CERN Document Server

    Wilken, Rowan

    2014-01-01

    Not only is locative media one of the fastest growing areas in digital technology, but questions of location and location-awareness are increasingly central to our contemporary engagements with online and mobile media, and indeed media and culture generally. This volume is a comprehensive account of the various location-based technologies, services, applications, and cultures, as media, with an aim to identify, inventory, explore, and critique their cultural, economic, political, social, and policy dimensions internationally. In particular, the collection is organized around the perception that the growth of locative media gives rise to a number of crucial questions concerning the areas of culture, economy, and policy.

  11. Acoustic Radiation Force Impulse Elastography for Efficacy Evaluation after Hepatocellular Carcinoma Radiofrequency Ablation: A Comparative Study with Contrast-Enhanced Ultrasound

    Directory of Open Access Journals (Sweden)

    Xiaohong Xu

    2014-01-01

    Full Text Available Aim. To explore acoustic radiation force impulse (ARFI elastography in assessing residual tumors of hepatocellular carcinoma (HCC after radiofrequency ablation (RFA. Materials and Methods. There were 83 HCC lesions among 72 patients. All patients were examined with ARFI, contrast enhanced ultrasound (CEUS, and CT or MRI. Tumor brightness on virtual touch tissue imaging (VTI and shear wave velocity (SWV were assessed before and approximately one month after RFA. Results. There were 14 residual tumors after RFA. VTI showed that all the tumors were darker after RFA. VTI was not able to distinguish the ablated lesions and the residual tumors. 13 residual tumor lesions were detected by CEUS. All completely ablated nodules had SWV demonstration of x.xx., while with those residual nodules, 6 tumors had x.xx measurement and 8 tumors had measurable SWV. nine lesions with residual tumors occurred in cirrhosis subjects and 5 lesions with residual tumors occurred in fibrosis subjects; there was no residual tumor in the normal liver subjects. Conclusion. VTI technique cannot demonstrate residual tumor post RFA. While SWV measurement of less than x.xx is likely associated with residual tumors, measurement of less than x.xx cannot exclude residual tumors. Liver cirrhosis is associated with decreased chance of a complete ablation.

  12. Acoustic Radiation Force Impulse Elastography for Efficacy Evaluation after Hepatocellular Carcinoma Radiofrequency Ablation: A Comparative Study with Contrast-Enhanced Ultrasound

    Science.gov (United States)

    Xu, Xiaohong; Luo, Liangping; Chen, Jiexin; Wang, Jiexin; Zhou, Honglian; Li, Mingyi; Jin, Zhanqiang; Chen, Nianping; Miao, Huilai; Lin, Manzhou; Dai, Wei; Ahuja, Anil T.; Wang, Yi-Xiang J.

    2014-01-01

    Aim. To explore acoustic radiation force impulse (ARFI) elastography in assessing residual tumors of hepatocellular carcinoma (HCC) after radiofrequency ablation (RFA). Materials and Methods. There were 83 HCC lesions among 72 patients. All patients were examined with ARFI, contrast enhanced ultrasound (CEUS), and CT or MRI. Tumor brightness on virtual touch tissue imaging (VTI) and shear wave velocity (SWV) were assessed before and approximately one month after RFA. Results. There were 14 residual tumors after RFA. VTI showed that all the tumors were darker after RFA. VTI was not able to distinguish the ablated lesions and the residual tumors. 13 residual tumor lesions were detected by CEUS. All completely ablated nodules had SWV demonstration of x.xx., while with those residual nodules, 6 tumors had x.xx measurement and 8 tumors had measurable SWV. nine lesions with residual tumors occurred in cirrhosis subjects and 5 lesions with residual tumors occurred in fibrosis subjects; there was no residual tumor in the normal liver subjects. Conclusion. VTI technique cannot demonstrate residual tumor post RFA. While SWV measurement of less than x.xx is likely associated with residual tumors, measurement of less than x.xx cannot exclude residual tumors. Liver cirrhosis is associated with decreased chance of a complete ablation. PMID:24895624

  13. On Media Education

    Science.gov (United States)

    Fedorov, Alexander

    2008-01-01

    This monograph analyzes the theory and practice of media education and media literacy. The book also includes the list of Russian media education literature and addresses of websites of the associations for media education.

  14. More Media, More People—On Social & Multimodal Media Intelligence

    OpenAIRE

    Degerstedt, Lars; Pelle, Snickars

    2017-01-01

    The purpose of this article is to address some challenges facing media intelligence in general, and competitive intelligence in particular within an altered information landscape. To understand this new situation, the notion of social and multimodal media intelligence are introduced. With cases taken primarily from the Swedish media intelligence sector, we argue that data driven media intelligence today needs to pay increasing attention to new forms of (A.) crowd-oriented and (B.) multimedia-...

  15. PENGEMBANGAN MEDIA PEMBELAJARAN FILM ANIMASI SEBAGAI MEDIA PEMBELAJARAN KONSEP FOTOSINTESIS

    Directory of Open Access Journals (Sweden)

    Umrotul Hasanah

    2015-11-01

    Full Text Available The research aims to develop animation film as a learning media in photosynthesis concept learning and to know the results of the assessment of the learning media expert test the concept of photosynthesis animated films. This research is Research and Development (R&D. The research used questionnaire  Aspects of assessment in terms of the media covering aspects of technical quality, narration, and music/sound effects. Aspects of the assessment of the suitability of the material terms covering the material aspects of the curriculum, the clarity of the material, the order of the material, communicative, suitability of the material with the purpose of learning, material relationship with the students’ critical thinking skill, and material relationship with motivation. Media expert test against “Cahaya dan Fotosintesis” animated film made by media experts with a percentage of 80,6% with the as good category, and  92,5% are material expert excellent category. Based on the “Cahaya dan Fotosintesis” animated film expert test to students can be tasted on a limited basis, after the media deficiencies corrected. Penelitian ini bertujuan untuk mengembangkan media pembelajaran film animasi pada konsep fotosintesis dan untuk mengetahui hasil penilaian uji ahli terhadap media pembelajaran film animasi pada konsep fotosintesis. Penelitian ini merupakan penelitian research and development (R & D. Teknik pengumpulan data dengan menggunakan angket. Aspek penilaian dari segi media meliputi aspek kualitas teknik, narasi dan musik/efek suara. Aspek penilaian dari segi materi meliputi aspek kesesuaian materi dengan kurikulum, kejelasan materi, urutan materi, komunikatif, kesesuaian soal evaluasi, kesesuaian materi dengan tujuan pembelajaran, hubungan materi dengan kemampuan berpikir kritis dan hubungan materi dengan motivasi. Uji ahli terhadap media film animasi “Cahaya dan Fotosintesis” dilakukan oleh ahli media dengan perolehan persentse 80,6% dengan

  16. Electrokinetic and Poroelastic Characterization of Porous Media : Application to CO2 storage monitoring

    NARCIS (Netherlands)

    Kirichek, O.J.

    2018-01-01

    Monitoring the properties of a CO2 storage reservoir is important for two main reasons: firstly, to verify that the injected CO2 is safely contained in the reservoir rock as planned, and secondly, to provide data which can be used to update the existing reservoir models and support eventual

  17. Aftershocks, groundwater changes and postseismic ground displacements related to pore pressure gradients: Insights from the 2012 Emilia-Romagna earthquake

    Science.gov (United States)

    Albano, Matteo; Barba, Salvatore; Solaro, Giuseppe; Pepe, Antonio; Bignami, Christian; Moro, Marco; Saroli, Michele; Stramondo, Salvatore

    2017-07-01

    During the 2012 Emilia-Romagna (Italy) seismic sequence, several time-dependent phenomena occurred, such as changes in the groundwater regime and chemistry, liquefaction, and postseismic ground displacements. Because time-dependent phenomena require time-dependent physical mechanisms, we interpreted such events as the result of the poroelastic response of the crust after the main shock. In our study, we performed a two-dimensional poroelastic numerical analysis calibrated with Cosmo-SkyMed interferometric data and measured piezometric levels in water wells. The simulation results are consistent with the observed postseismic ground displacement and water level changes. The simulations show that crustal volumetric changes induced by poroelastic relaxation and the afterslip along the main shock fault are both required to reproduce the amplitude (approximately 4 cm) and temporal evolution of the observed postseismic uplift. Poroelastic relaxation also affects the aftershock distribution. In fact, the aftershocks are correlated with the postseismic Coulomb stress evolution. In particular, a considerably higher fraction of aftershocks occurs when the evolving poroelastic Coulomb stress is positive. These findings highlight the need to perform calculations that adequately consider the time-dependent poroelastic effect when modeling postseismic scenarios, especially for forecasting the temporal and spatial evolution of stresses after a large earthquake. Failing to do so results in an overestimation of the afterslip and an inaccurate definition of stress and strain in the postseismic phase.

  18. Social Media Reputation

    DEFF Research Database (Denmark)

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

    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......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...... of the phenomenon, and highlight theoretically relevant differences and interrelationships between reputational dynamics involving news media and social media....

  19. 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.

  20. 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...

  1. Parents and the media: causes and consequences of parental media socialization

    NARCIS (Netherlands)

    Notten, N.J.W.R.

    2011-01-01

    Media literacy is an important part of socialization and with media use becoming ever more essential in modern society, research on parental media socialization is vital. This study proposes the intergenerational transmission of parent’s media competencies, as a specific kind of cultural

  2. Biomechanical paradigm and interpretation of female pelvic floor conditions before a treatment

    Directory of Open Access Journals (Sweden)

    Lucente V

    2017-08-01

    Full Text Available Vincent Lucente,1 Heather van Raalte,2 Miles Murphy,1 Vladimir Egorov3 1The Institute for Female Pelvic Medicine and Reconstructive Surgery, Allentown, PA, USA; 2Princeton Urogynecology, Princeton, NJ, USA; 3Artann Laboratories, Trenton, NJ, USA Background: Further progress in restoring a woman’s health may be possible if a patient with a damaged pelvic floor could undergo medical imaging and biomechanical diagnostic tests. The results of such tests could contribute to the analysis of multiple treatment options and suggest the optimal one for that patient.Aim: To develop a new approach for the biomechanical characterization of vaginal conditions, muscles, and connective tissues in the female pelvic floor.Methods: Vaginal tactile imaging (VTI allows biomechanical assessment of the soft tissue along the entire length of the anterior, posterior, and lateral vaginal walls at rest, with manually applied deflection pressures and with muscle contraction, muscle relaxation, and Valsalva maneuver. VTI allows a large body of measurements to evaluate individual variations in tissue elasticity, support defects, as well as pelvic muscle function. Presuming that 1 the female pelvic floor organs are suspended by ligaments against which muscles contract to open or close the outlets and 2 damaged ligaments weaken the support and may reduce the force of muscle contraction, we made an attempt to characterize multiple pelvic floor structures from VTI data.Results: All of the 138 women enrolled in the study were successfully examined with the VTI. The study subjects have had normal pelvic support or pelvic organ prolapse (stages I–IV. The average age of this group of subjects was 60±15 years. We transposed a set of 31 VTI parameters into a quantitative characterization of pelvic muscles and ligamentous structures. Interpretation of the acquired VTI data for normal pelvic floor support and prolapse conditions is proposed based on biomechanical assessment of the

  3. Media Literacy Bibliography.

    Science.gov (United States)

    Duncan, Barry

    1989-01-01

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

  4. Anisotropic wave-equation traveltime and waveform inversion

    KAUST Repository

    Feng, Shihang

    2016-09-06

    The wave-equation traveltime and waveform inversion (WTW) methodology is developed to invert for anisotropic parameters in a vertical transverse isotropic (VTI) meidum. The simultaneous inversion of anisotropic parameters v0, ε and δ is initially performed using the wave-equation traveltime inversion (WT) method. The WT tomograms are then used as starting background models for VTI full waveform inversion. Preliminary numerical tests on synthetic data demonstrate the feasibility of this method for multi-parameter inversion.

  5. 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.

  6. 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...... functions. A classification of public relations functions including fourteen functions in three categories has taken as research framework and by using a questionnaire, eight media have been asked to rank for each function, includes Television, Radio, Newspaper, Magazine, Classified Ads, Internet Websites......, 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...

  7. Anomalous incident-angle and elliptical-polarization rotation of an elastically refracted P-wave

    Science.gov (United States)

    Fa, Lin; Fa, Yuxiao; Zhang, Yandong; Ding, Pengfei; Gong, Jiamin; Li, Guohui; Li, Lijun; Tang, Shaojie; Zhao, Meishan

    2015-08-01

    We report a newly discovered anomalous incident-angle of an elastically refracted P-wave, arising from a P-wave impinging on an interface between two VTI media with strong anisotropy. This anomalous incident-angle is found to be located in the post-critical incident-angle region corresponding to a refracted P-wave. Invoking Snell’s law for a refracted P-wave provides two distinctive solutions before and after the anomalous incident-angle. For an inhomogeneously refracted and elliptically polarized P-wave at the anomalous incident-angle, its rotational direction experiences an acute variation, from left-hand elliptical to right-hand elliptical polarization. The new findings provide us an enhanced understanding of acoustical-wave scattering and lead potentially to widespread and novel applications.

  8. Media - Our friends (improving our relationship with media)

    International Nuclear Information System (INIS)

    Stiopol, Mihaela; Bilegan, Iosif Constantin

    2000-01-01

    The paper will present the principles, goals and the steps followed in establishing media relationships. It will highlight the company' s activity developed over this year within the Romanian Public Information Programme in the nuclear field, in order to establish friendly relationship with media, as well as the conclusions we have reached in performing such an activity. In this moment, the way public receives the real information has a great impact on the future development of this alternative and the role of media is an essential one. So, we consider that the utility mission is to act promptly to transmit to the public complete and honest information with the help of this important segment which is media

  9. 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

  10. Making Media Studies

    Directory of Open Access Journals (Sweden)

    David Gauntlett

    2015-12-01

    Full Text Available This podcast is a recording of a research seminar that took place on December 3, 2015, at the University of Westminster's Communication and Media Research Institute (CAMRI. In this contribution, David Gauntlett discusses his new book, Making Media Studies, and other new work. In Making Media Studies (Peter Lang, 2015, Gauntlett proposes a vision of media studies based around doing and making – not about the acquisition of skills, as such, but an experience of building knowledge and understanding through creative hands-on engagement with all kinds of media. Gauntlett suggests that media studies scholars have failed to recognise the significance of everyday creativity – the vital drive of people to make, exchange, and learn together, supported by online networks. He argues that we should think about media in terms of conversations, inspirations, and making things happen. Media studies can be about genuine social change, he suggests, if we recognise the significance of everyday creativity, work to transform our tools, and learn to use them wisely. David Gauntlett is a Professor in the School of Media, Arts and Design at the University of Westminster, where he is also the School's Co-Director of Research. He is the author of several books, including: Creative Explorations (2007, Media, Gender and Identity: An Introduction (2nd edition 2008, Making is Connecting (2011, and Making Media Studies (2015. He has made a number of popular online resources, videos and playthings, and has pioneered creative research and workshop methods. He is external examiner for Information Experience Design at the Royal College of Art, London.

  11. Ageing in media: rethinking the studying of media use in later life

    DEFF Research Database (Denmark)

    Givskov, Cecilie

    in the realms of politics and commerce – and, of course, media. Ageing populations are key drivers of media sales, especially in the areas of mobile and online media, and they are the dominant audience groups following the news. At the same time, social institutions realign their relations with (older) citizens...... characterized by chronological life phase and generational perspectives, to some extent influenced by medicalised images of old age where ageing after the 60s gets correlated with a loss of intellectual and creative resources, a decline of social life and physical health, and with regard to media, a lack...... through digital media. In spite of this inversion of the age pyramid and their significance as media users and active citizens, older people’s media use is rarely the focus of media producers or communication scholars. What research does get carried out involving older people’s media use is generally...

  12. Media violence in the information society in the context of media anthropology

    Directory of Open Access Journals (Sweden)

    N. A. Mazorenko

    2014-01-01

    Full Text Available The article discusses media violence as special case of deviant manifestations of the individual and collective social body. It’s stated that in the late 20th century emphasis had shifted from the sociological and ethnographic works towards a more wide format of a man and the media studies. According to the author, it was caused by the forming of the media anthropology as human­oriented paradigm of the postmodern media. The place of media violence in problematic field of the media anthropology field is defined. It’s considered as a result of the somatic transformations in the media and the cultural space of the information society. Mass media have been products of culture and social life and at the same time factors of the identity’s construction. Such characteristic properties require more conscious of morality and responsibility. Media need to understand and represent new modes of physicality / spirituality and rationality / irrationality in the media and socio­political life. Due to weakening or decline of spiritual and intellectual component in the psycho­somatic existence threatens to turn society into collective grotesque body, and media that exploit these social strain, into media spectacle, distorted and grotesque in the worst sense of the word. In this article, the method of anthropological reduction, and elements of cultural­historical and structural­functional analysis have been used.

  13. Radiographic contrast media

    International Nuclear Information System (INIS)

    Golman, K.; Holtz, E.; Almen, T.

    1987-01-01

    Contrast media are used in diagnostic radiology to enhance the X-ray attenuation between a body structure of interest and the surrounding tissue. A detail becomes perceptible on a roentgenogram only when its contrast exceeds a minimum value in relation to the background. Small areas of interest must have higher contrast than the background. The contrast effect depends on concentration of the contrast media with the body. A high contrast media concentration difference thus gives rise to more morphological details in the radiographs. Contrast media can be divided into negative contrast media such as air and gas which attenuate X-rays less than the body tissues, and positive contrast materials which attenuate X-rays more than the body tissues. The positive contrast media all contain either iodine (atomic number 53) or barium (atomic number 56) and can be divided into water-insoluble and water-soluble contrast media

  14. The Media Mixer

    DEFF Research Database (Denmark)

    Vestergaard, Vitus; Mortensen, Christian Hviid

    2011-01-01

    content. The media content is created by the user in the museum's physical environment, but it can be mixed with material from web archives. It is the intention that the users learn about media through participatory and creative processes with media where the borders between producing, playing......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...

  15. 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...

  16. 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.

  17. Media Activism and the Academy, Three Cases: Media Democracy Day, Open Media, and NewsWatch Canada

    Directory of Open Access Journals (Sweden)

    David Skinner

    2015-12-01

    Full Text Available In Canada, there is a relatively strong tradition of activist scholarship in media and communication studies. However, very little research has been undertaken on how working in the university may contextualize the ways in which academic workers participate in activist media projects. Focusing on three such projects – Media Democracy Day, Open Media, and NewsWatch Canada – this article draws upon elements of political economy and Bourdieu’s field theory to consider how the different characters of the academic and activist fields work to enable and constrain the abilities of faculty to engage with them.

  18. 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.

  19. Kesadaran Kritis Mahasiswa Terhadap Media Sosial (Studi Deskriptif Kualitatif Literasi Media Tentang Kesadaran Kritis Mahasiswa Ilmu Komunikasi USU Terhadap Media Sosial)

    OpenAIRE

    Nurhaliza, Ade

    2017-01-01

    This study entitled “Critical Awareness of Communication Student in Social Media”. This study aimed to find out how student’s critical awareness in social media in media literacy context. The Theories used in this study are media literacy theory, critical awareness theory, new media and digital media literacy, and social media. The method used in this study is qualitative descriptive which describes the condition on the ground, reality, and the situation or some phenomenones. The result showe...

  20. Intermediality and media change

    OpenAIRE

    2012-01-01

    This book is about intermediality as an approach to analysing and understanding media change. Intermediality and Media Change is critical of technological determinism that characterises 'new media discourse' about the ongoing digitalization, framed as a revolution and creating sharp contrasts between old and new media. Intermediality instead emphasises paying attention to continuities between media of all types and privileges a comparative perspective on technological changes in media over ti...

  1. Media exposure and health in Europe: Mediators and moderators of media systems

    NARCIS (Netherlands)

    Blom, N.; Zanden, R. van der; Buijzen, M.A.; Scheepers, P.L.H.

    2016-01-01

    This study examined media exposure as an explanatory factor for individual and cross-national differences in self-assessed general health. In studying media exposure, traditional media (television, radio, and newspapers) and contemporary media (internet) were separately considered. Aside from

  2. 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.

  3. Social media visibility

    DEFF Research Database (Denmark)

    Uldam, Julie

    2018-01-01

    of activists remains under-researched. This article examines BP’s surveillance of activists who criticise the company’s corporate social responsibility (CSR) programme as ‘greenwashing’. In this way, it goes beyond corporations’ uses of big data and instead explores how they monitor and discuss strategies......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...

  4. 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...

  5. Akun Resmi Media Sosial IMAJINASI FISIP USU Sebagai Media Pencarian Informasi (Studi Deskriptif Kuantitatif Penggunaan Akun Resmi Media Sosial IMAJINASI FISIP USU)

    OpenAIRE

    Nurdiningrum, Nurul

    2017-01-01

    130904171 Penelitian ini berjudul Akun Resmi Media Sosial IMAJINASI FISIP USU sebagai Media Pencarian Informasi (Studi Deskriptif Kuantitatif Penggunaan Akun Resmi Media Sosial IMAJINASI FISIP USU sebagai Media Pencarian Informasi pada Mahasiswa Ilmu Komunikasi).Tujuan penelitian adalah untuk mengetahui peranan akun resmi media sosial IMAJINASI FISIP USU sebagai media pencarian informasi pada mahasiswa Departemen Ilmu Komunikasi FISIP USU, untuk mengetahui jenis-jenis informasi yang dibagi...

  6. 'Frozen' media subsidies during a time of media change

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Kleis

    2014-01-01

    documents and secondary sources, I show that media subsidies have largely remained frozen in their late-20th century form. The absence of major reform means that media subsidies are increasingly subject to policy drift, a process by which the operations and effectiveness of policies change not because......Media systems around the world have changed in significant ways in the early 21st century. In this article, I analyse how various forms of media subsidies have changed in response to these transformations in a sample of six different affluent democracies. On the basis of interviews, official......) a perceived shortage of desirable, cost-effective, and governable alternatives to existing policies....

  7. Harnessing the landscape of microbial culture media to predict new organism–media pairings

    Science.gov (United States)

    Oberhardt, Matthew A.; Zarecki, Raphy; Gronow, Sabine; Lang, Elke; Klenk, Hans-Peter; Gophna, Uri; Ruppin, Eytan

    2015-01-01

    Culturing microorganisms is a critical step in understanding and utilizing microbial life. Here we map the landscape of existing culture media by extracting natural-language media recipes into a Known Media Database (KOMODO), which includes >18,000 strain–media combinations, >3300 media variants and compound concentrations (the entire collection of the Leibniz Institute DSMZ repository). Using KOMODO, we show that although media are usually tuned for individual strains using biologically common salts, trace metals and vitamins/cofactors are the most differentiating components between defined media of strains within a genus. We leverage KOMODO to predict new organism–media pairings using a transitivity property (74% growth in new in vitro experiments) and a phylogeny-based collaborative filtering tool (83% growth in new in vitro experiments and stronger growth on predicted well-scored versus poorly scored media). These resources are integrated into a web-based platform that predicts media given an organism's 16S rDNA sequence, facilitating future cultivation efforts. PMID:26460590

  8. 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...

  9. 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…

  10. Making Dutch pupils media conscious: preadolescents' self-assessment of possible media risks and the need for media education

    NARCIS (Netherlands)

    Küter-Luks, Theresa; Heuvelman, A.; Peters, O.

    2011-01-01

    Despite clear European and Dutch policies about media education, there is currently no media education curriculum in Dutch schools. A survey among preadolescents (n = 257) in six primary schools in the Netherlands included questions regarding media access, fears, risks, parental mediation of

  11. Educational Potential of New Media

    Directory of Open Access Journals (Sweden)

    Maria Yu. Kazak

    2017-11-01

    Full Text Available Digitalization of the mass media, which has radically changed the information environment, creates new opportunities for self-education and upgrowth of the audience. The paper defines the communicative and cultural status of new media, characterizes the socio-cultural and technological aspects of their dynamics; substantiates the necessity of elaborating mechanisms for systematization of heterogeneous information flows and elaborating criteria for their evaluation in the era of globalization of the media sphere, what implies a qualitatively different level of media competence of the audience, provided with such factors as media education, media coverage, media criticism. The definition of concepts "media competence", "media enlightenment", "media education", "media criticism" is given and their functional areas are delineated. Social networks are considered as an important tool for media enlightenment which provides significant opportunities for promoting cultural achievements in the new media environment.

  12. Solution of Media Risk and Social Responsibility Governance of Social Media

    Directory of Open Access Journals (Sweden)

    Zhang Yuan

    2017-01-01

    Full Text Available The rapid development of media technology makes the modern society become a “social media” or even “over social media”, the rise of social media makes it beyond the tool attribute, and become an important force in the reconstruction of contemporary society, the risk of concomitant. The anomie and breach of Social media regularly staged, weakened its positive social function, forcing us to think about the social responsibility of social media,which are reflections on the lack of responsibility, but also positive response of resolving the media risk and ask for moral strength.

  13. Adolescents and media literacy.

    Science.gov (United States)

    McCannon, Robert

    2005-06-01

    In the face of media industry consolidation, fewer people control media content which makes it harder for parents and citizens to know the research about media-related issues, such as video game violence, nutrition, and sexual risk-taking. Media literacy offers a popular and potentially successful way to counter the misinformation that is spread by Big Media public relations.

  14. Fra massemedier til mediesystem - om kodediskussionen i systemteoretisk medieforskning [From mass media to media system - code discussions in systems theoretical media research

    Directory of Open Access Journals (Sweden)

    Mikkel Fugl Eskjær

    2010-11-01

    Full Text Available Systems theoretical media research raises the question whether the mass media constitute a unified institution, or whether the media, due to their internal differences, should be considered individually and independent of each other. By inscribing the media in a general social theory, systems theory conceptualises the media as an autonomous functional system. This intention is most clearly illustrated by the efforts to identify a shared code for the entire media system. Based on the media theory of Niklas Luhmann, this paper offers a critical presentation of the code discussion within systems theoretical media research. The first part of the paper briefly introduces the systems theoretical notion of a code as well as Luhmann’s definition of the media system as organised and regulated by the code of information. The second part presents a number of alternative suggestions and definitions of the media system’s code, which both indicate the scope of systems theoretical media research, but also point to some of the limitations in the systems theoretical approach. In the last part, the paper takes a critical look at the systems theoretical code discussion by arguing that a too narrow focus on code definitions is blocking a more productive investigation of the conditions, evolution, and autonomy of the media system.

  15. 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.

  16. 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....

  17. The development of children's language and ethical media competences and media skills

    OpenAIRE

    Valli, Raine; Hautaviita, Janika; Meriläinen, Merja

    2015-01-01

    The children's developing media competences and media skills are evaluated in this article on the basis of the evaluation indicator developed by Hautaviita (2012). The indicator has been developed for measuring the 6–9-year-old children's (the preschoolers and the pupils in grades 1-2) media competences. In it, the children's developing media skills are divided into practical, social, language and ethical media competences, of which this article concentrates on the last two, language and ethi...

  18. 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 ...

  19. 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…

  20. Media Pluralism and Diversity

    DEFF Research Database (Denmark)

    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...

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

    Science.gov (United States)

    Levitskaya, Anastasia

    2015-01-01

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

  2. 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,…

  3. Procedural Media Representation

    OpenAIRE

    Henrysson, Anders

    2002-01-01

    We present a concept for using procedural techniques to represent media. Procedural methods allow us to represent digital media (2D images, 3D environments etc.) with very little information and to render it photo realistically. Since not all kind of content can be created procedurally, traditional media representations (bitmaps, polygons etc.) must be used as well. We have adopted an object-based media representation where an object can be represented either with a procedure or with its trad...

  4. The Media Mixer

    DEFF Research Database (Denmark)

    Vestergaard, Vitus; Mortensen, Christian Hviid

    In recent years many museums have experimented with different approaches to involving users through digital media. We explore how remixing and content sharing can be used as a means for user participation. 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 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...... the museum users can produce, deconstruct, reconstruct and finally publish and share digital media content. The media content is created by the user in the museums physical environment, but it can be mixed with material from local or global archives. In that way the gap between the analogue and the digital...

  5. PENGEMBANGAN MEDIA PEMBELAJARAN FILM ANIMASI SEBAGAI MEDIA PEMBELAJARAN KONSEP FOTOSINTESIS

    Directory of Open Access Journals (Sweden)

    Umrotul Hasanah

    2015-11-01

    Full Text Available The research aims to develop animation film as a learning media in photosynthesis concept learning and to know the results of the assessment of the learning media expert test the concept of photosynthesis animated films. This research is Research and Development (R&D. The research used questionnaire Aspects of assessment in terms of the media covering aspects of technical quality, narration, and music/sound effects. Aspects of the assessment of the suitability of the material terms covering the material aspects of the curriculum, the clarity of the material, the order of the material, communicative, suitability of the material with the purpose of learning, material relationship with the students’ critical thinking skill, and material relationship with motivation. Media expert test against “Cahaya dan Fotosintesis” animated film made by media experts with a percentage of 80,6% with the as good category, and 92,5% are material expert excellent category. Based on the “Cahaya dan Fotosintesis” animated film expert test to students can be tasted on a limited basis, after the media deficiencies corrected.

  6. Media Outlook 2016: A Survey of UK Media Trends and Firm Capabilities

    OpenAIRE

    Oliver, John James

    2016-01-01

    The aim of this survey is to understand the changing nature of the UK media environment, emerging trends and the management practices of media executives. This is the fourth year that the survey has run, and already we are seeing immense changes in the way media firms are adapting to a changing competitive landscape. This year, the focus of the survey has been on assessing media firm capabilities and the ability to adapt media strategy, business models and capabilities to new industry dynamic...

  7. 75 FR 77670 - SuperMedia, LLC, Formerly Known as Idearc Media, LLC, a Subsidiary of SuperMedia Information...

    Science.gov (United States)

    2010-12-13

    ... Known as Idearc Media, LLC, a Subsidiary of SuperMedia Information Services, LLC Publishing Group, Troy... Subsidiary of SuperMedia Information Services, LLC, Troy, New York, to apply for Trade Adjustment Assistance..., Publishing Group, Troy, New York, who became totally or partially separated from employment on or after...

  8. Advocates' Experiences With Media and the Impact of Media on Human Trafficking Advocacy.

    Science.gov (United States)

    Houston-Kolnik, Jaclyn D; Soibatian, Christina; Shattell, Mona M

    2017-02-01

    The present qualitative study explores advocates' opinions of misinformation about human trafficking in the media and describes advocates' strategies to counter the misinformation presented by the media. Thus, 15 advocates who work against human trafficking in Chicago-based nonprofit organizations participated in semistructured interviews about their opinions and strategies. Data were analyzed using thematic content analysis. The present study identifies specific misperceptions of human trafficking in the media, highlights advocates' opinions of this misinformation, and discusses advocates' strategies to counteract inaccurate media, adding support to the role of media advocacy. Advocates note how media images shape and perpetuate stereotypes of trafficking through glamorizing sex work and sensationalizing stories that are most often international depictions of trafficking. Advocates report media generally shares only a piece of the story, simplifying the stories of survivors and the issue of human trafficking. Advocates critique media perpetuating these misperceptions for how they may contribute to policies and programs which fail to address structural factors that create vulnerabilities to be trafficked and the multisystem needs of survivors. However, advocates also note misperceptions can be counteracted by producing sensitive, informed media through social platforms. Advocates share their strategies counteracting misinformation through engaging in informative conversations, utilizing social media to educate, and promoting media messages of survivor agency. Research, clinical, and policy implications are also discussed. The present study emphasizes the importance of decision makers and service providers being critical consumers of media and to assess how media portrayals may (or may not) inform their understanding and response to the issue.

  9. Open Media Science

    DEFF Research Database (Denmark)

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

    2016-01-01

    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...

  10. DEVELOPMENT OF STUDENTS’ MEDIA LITERACY IN THE PROCESS OF CREATING SCHOOL MEDIA

    Directory of Open Access Journals (Sweden)

    Julia Rybina

    2017-04-01

    Full Text Available Nowadays, a rapid development of information and communication technologies enables combine a number of formats for presenting information into one communication unit. That is why the media (Internet especially is not just tools for young generation for learning the modern world. Children enjoy in dealing with modern technologies. However not everyone has sufficient skills to objectively assess the true meaning of the information received. That is why children are more inclined for their mind to be manipulated and they are more inclined for blind imitating of attractive images. Owning to the above, the most priority-driven of modern education is the usage of information and communication technologies and media education for forming the skills of students' orientation in the information field and for forming the development of media immunity of the personality which makes the personality able to resist to the aggressive media space. Teachers face the challenge of introducing media education in middle and high schools. To implement the media education at the municipal institution regional specialized residential school “Giftedness” the pedagogical experiment was carried out there. The basis of the experiment is the generalized model of media literacy development for students that was used during for making and functioning the school newspaper «D.A.R-media». Theoretical aspects of the implementation of media education in the teaching and educational process of a specialized educational institution are considered in this study. A model for the development of the media literacy of students in the process of creating a school printed publication is proposed. Some results of research on the level of media literacy of students are highlighted and prospects for work on introducing media education of teachers and teachers are outlined.

  11. Making Dutch Pupils Media Conscious: Preadolescents' Self-Assessment of Possible Media Risks and the Need for Media Education

    Science.gov (United States)

    Kuter-Luks, Theresa; Heuvelman, Ard; Peters, Oscar

    2011-01-01

    Despite clear European and Dutch policies about media education, there is currently no media education curriculum in Dutch schools. A survey among preadolescents (n = 257) in six primary schools in the Netherlands included questions regarding media access, fears, risks, parental mediation of television and the internet, and the need for media…

  12. 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....

  13. 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.

  14. 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.

  15. Pengguna Media Interaktif Sebagai Kenyataan Maya: Studi Resepsi Khalayak Suarasurabaya.net Sebagai Media Interaktif

    Directory of Open Access Journals (Sweden)

    Ido Prijana Hadi

    2011-07-01

    Full Text Available My aim in writing this paper is to describe that in this fast-changing world, media in Indonesia has undergone a rapid transformation. Digital technology continues to reshape the mass media landscape using internet technology. Internet brings a technical communication revolution, a fundamental change takes place in the structure of connections, artificial memories and the reproduction of their content. Internet technology has made communication much easier and less expensive. It has attracted many people and has penetrated into people’s daily lives. The mass media also have accepted the internet. Almost all forms of traditional media (old media in local media, such as radio, television, and newspaper have extended their work into this new field. The internet and the World Wide Web have both significantly influenced modern journalism. In online media allows readers to enjoy browsing their product and service of contents, such as news feed, podcasts, desktop alert, news on mobile phones, PDA and others mobile devices. Online media offer not only text but also digital images , audio file, moving images (video, internet radio and internet t v. The interactive features of the internet seemingly imply that online media have more advantages than traditional media forms (old media. So, the internet have dramatically evolved become new media with characteristic multimedia, hypertext, interactivity, archives , and virtuality. The most important structural new media characteristic is the integration of telecommunications, data communications and mass communication in a single medium – it is the convergence. It should be pointed out that the trend toward digital is affecting the various media and brings the local media in East Java to become a global media, where breaking news from Surabaya or anywhere in East Java is transmitted to around the world in a matter of minutes . The research was carried out to find out how user reception on convergence media

  16. Selection and Evaluation of Media for Behavioral Health Interventions Employing Critical Media Analysis.

    Science.gov (United States)

    Wilson, Patrick A; Cherenack, Emily M; Jadwin-Cakmak, Laura; Harper, Gary W

    2018-01-01

    Although a growing number of psychosocial health promotion interventions use the critical analysis of media to facilitate behavior change, no specific guidelines exist to assist researchers and practitioners in the selection and evaluation of culturally relevant media stimuli for intervention development. Mobilizing Our Voices for Empowerment is a critical consciousness-based health enhancement intervention for HIV-positive Black young gay/bisexual men that employs the critical analysis of popular media. In the process of developing and testing this intervention, feedback on media stimuli was collected from youth advisory board members (n = 8), focus group participants (n = 19), intervention participants (n = 40), and intervention facilitators (n = 6). A thematic analysis of qualitative data resulted in the identification of four key attributes of media stimuli and participants' responses to media stimuli that are important to consider when selecting and evaluating media stimuli for use in behavioral health interventions employing the critical analysis of media: comprehension, relevance, emotionality, and action. These four attributes are defined and presented as a framework for evaluating media, and adaptable tools are provided based on this framework to guide researchers and practitioners in the selection and evaluation of media for similar interventions.

  17. Cross-media advertising: brand promotion in an age of media convergence

    NARCIS (Netherlands)

    Voorveld, H.; Smit, E.; Neijens, P.; Diehl, S.; Karmasin, M.

    2013-01-01

    Cross-media advertising, in which more than one medium platform is used to communicate related brand content, has become widespread. Several reasons for cross-media strategies can be distinguished: target group extension, complementary effects, repetition, and synergy. Media synergy—the added value

  18. The impacts of post-media networks on the traditional media

    Directory of Open Access Journals (Sweden)

    Dr. Francisco Campos Freire

    2008-01-01

    Full Text Available The fast and successful penetration in society of the so-called social networks in the past two or three years has alarmed the traditional media. The new phenomenon reaches a wider audience, enhances advertising, achieves customization, and breaches some of the barriers of traditional media. The new communication channel is used already by millions of Internet users as their main source of information and entertainment. This research paper analyses the structure of eleven global social networks, which feature contents in Spanish and other languages, in relation to the electronic version (e-version of the main Spanish newspapers. The aim is to prove if the so-called social networks are a new type of media, a new platform for social relationships and post-media contents, which look more like the audiovisual media than the traditional newspapers.

  19. Comprehension of digital media

    International Nuclear Information System (INIS)

    Kim, Ju Hwan

    2008-11-01

    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. 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.

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

    OpenAIRE

    Iswandi Syahputra

    2017-01-01

    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. ...

  2. Turkish Press in Social Media

    OpenAIRE

    AYTEN, Adem

    2013-01-01

    Social media, is one of the most researched facts today by the commications fellows. To get in use by Web 2.0 social media becomes common due to the rise of using mobile technologies. Instead of competing with traditional media and being an alternative media, social media is a new media that traditional media can transfer its content to it and can benefit its advantages. Indeed,the traditional media carried its content to the websites to access of their readers/listeners/watchers to compete ...

  3. 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…

  4. 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

  5. The parental media mediation context of young children’s media use

    NARCIS (Netherlands)

    Piotrowski, J.T.; Barr, R.; Linebarger, D.N.

    2017-01-01

    Researchers widely agree that how children spend their time is an important predictor of the development of their skills, relationships, attitudes, and behavior patterns. And while media estimates indicate that media play a considerable presence in the daily life of most youngsters today, media use

  6. Understanding Social Media Logic

    OpenAIRE

    José van Dijck; Thomas Poell

    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 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 log...

  7. MediaTracker system

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval, D. M. (Dana M.); Strittmatter, R. B. (Richard B.); Abeyta, J. D. (Joline D.); Brown, J. (John); Marks, T. (Thomas), Jr.; Martinez, B. J. (Benny J.); Jones, D. B. (Dana Benelli); Hsue, W.

    2004-01-01

    The initial objectives of this effort were to provide a hardware and software platform that can address the requirements for the accountability of classified removable electronic media and vault access logging. The Media Tracker system software assists classified media custodian in managing vault access logging and Media Tracking to prevent the inadvertent violation of rules or policies for the access to a restricted area and the movement and use of tracked items. The MediaTracker system includes the software tools to track and account for high consequence security assets and high value items. The overall benefits include: (1) real-time access to the disposition of all Classified Removable Electronic Media (CREM), (2) streamlined security procedures and requirements, (3) removal of ambiguity and managerial inconsistencies, (4) prevention of incidents that can and should be prevented, (5) alignment with the DOE's initiative to achieve improvements in security and facility operations through technology deployment, and (6) enhanced individual responsibility by providing a consistent method of dealing with daily responsibilities. In response to initiatives to enhance the control of classified removable electronic media (CREM), the Media Tracker software suite was developed, piloted and implemented at the Los Alamos National Laboratory beginning in July 2000. The Media Tracker software suite assists in the accountability and tracking of CREM and other high-value assets. One component of the MediaTracker software suite provides a Laboratory-approved media tracking system. Using commercial touch screen and bar code technology, the MediaTracker (MT) component of the MediaTracker software suite provides an efficient and effective means to meet current Laboratory requirements and provides new-engineered controls to help assure compliance with those requirements. It also establishes a computer infrastructure at vault entrances for vault access logging, and can

  8. MediaTracker system

    International Nuclear Information System (INIS)

    Sandoval, D.M.; Strittmatter, R.B.; Abeyta, J.D.; Brown, J.; Marks, T. Jr.; Martinez, B.J.; Jones, D.B.; Hsue, W.

    2004-01-01

    The initial objectives of this effort were to provide a hardware and software platform that can address the requirements for the accountability of classified removable electronic media and vault access logging. The Media Tracker system software assists classified media custodian in managing vault access logging and Media Tracking to prevent the inadvertent violation of rules or policies for the access to a restricted area and the movement and use of tracked items. The MediaTracker system includes the software tools to track and account for high consequence security assets and high value items. The overall benefits include: (1) real-time access to the disposition of all Classified Removable Electronic Media (CREM), (2) streamlined security procedures and requirements, (3) removal of ambiguity and managerial inconsistencies, (4) prevention of incidents that can and should be prevented, (5) alignment with the DOE's initiative to achieve improvements in security and facility operations through technology deployment, and (6) enhanced individual responsibility by providing a consistent method of dealing with daily responsibilities. In response to initiatives to enhance the control of classified removable electronic media (CREM), the Media Tracker software suite was developed, piloted and implemented at the Los Alamos National Laboratory beginning in July 2000. The Media Tracker software suite assists in the accountability and tracking of CREM and other high-value assets. One component of the MediaTracker software suite provides a Laboratory-approved media tracking system. Using commercial touch screen and bar code technology, the MediaTracker (MT) component of the MediaTracker software suite provides an efficient and effective means to meet current Laboratory requirements and provides new-engineered controls to help assure compliance with those requirements. It also establishes a computer infrastructure at vault entrances for vault access logging, and can accommodate

  9. Solution of Media Risk and Social Responsibility Governance of Social Media

    OpenAIRE

    Zhang Yuan; Li Ming-De; Zhang Hong-Bang

    2017-01-01

    The rapid development of media technology makes the modern society become a “social media” or even “over social media”, the rise of social media makes it beyond the tool attribute, and become an important force in the reconstruction of contemporary society, the risk of concomitant. The anomie and breach of Social media regularly staged, weakened its positive social function, forcing us to think about the social responsibility of social media,which are reflections on the lack of responsibility...

  10. 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

  11. 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…

  12. Juggling with media : The consequences of media multitasking for adolescent development

    NARCIS (Netherlands)

    van der Schuur, W.A.

    2018-01-01

    More than ever, adolescents juggle with media. They use multiple media simultaneously, for example, they send text messages to their friends while watching a movie. In addition, they use media during academic and social activities, such as watching YouTube videos while doing homework. Although this

  13. Mixed-Media File Systems

    NARCIS (Netherlands)

    Bosch, H.G.P.

    1999-01-01

    This thesis addresses the problem of implementing mixed-media storage systems. In this work a mixed-media file system is defined to be a system that stores both conventional (best-effort) file data and real-time continuous-media data. Continuous-media data is usually bulky, and servers storing and

  14. PERIKLANAN DALAM MEDIA BARU (Advertising In The New Media )

    OpenAIRE

    Errika Dwi Setya Watie

    2016-01-01

    Advertising is currently getting a huge challenge. the number of ads , it is realized or not, effects on saturation of advertising. New era media presents new communications media to the community. This condition should be recognized by anyone working in the advertising, because the development of advertising is in line with a new media movement, so the expectansy of the intended market segment will be achieved better. Today, the challenge of a new style of advertising has been answered b...

  15. Measuring media multitasking : Development of a short measure of media multitasking for adolescents

    NARCIS (Netherlands)

    Baumgartner, Susanne E.; Lemmens, Jeroen S.; Weeda, Wouter D.; Huizinga, Mariette

    2017-01-01

    Although media multitasking is an increasingly occurring form of media use, there are currently no validated, short instruments to measure media multitasking among adolescents. The aim of the present study, therefore, was to develop a short media multitasking measure for adolescents (MMM-S). Two

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

    Directory of Open Access Journals (Sweden)

    Hui-Ju Tsai

    2016-04-01

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

  17. Mediating social media use : connecting parents mediation strategies and social media literacy

    OpenAIRE

    Daneels, Rowan; Vanwynsberghe, Hadewijch

    2017-01-01

    Abstract: Increasingly complex and multipurpose social media platforms require digital competences from parents and adolescents alike. While adolescents grow up with social media, parents have more difficulties with them, leading to uncertainties regarding their adolescents social media mediation. This study contributes to parental mediation research by (1) investigating whether mediation strategies defined by previous research are also relevant for social media use, and (2) exploring whether...

  18. 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

  19. Balancing media environments

    DEFF Research Database (Denmark)

    Olesen, Mogens

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

  20. 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 ...

  1. Media Convergence: the Culture Dimensions of Thinking%Media Convergence:the Culture Dimensions of Thinking

    Institute of Scientific and Technical Information of China (English)

    Shen Diao; Lan Ju

    2017-01-01

    In the process of meida Convergence,many researchers paid excessive attention to media technology,industry and management,and ignored the culture dimensions of media convergence.Therefore,to transcend media convergence technology,industrial thinking and more to the particularity attach importance to cultural media,it is a right way to achieve media convergence.But in the context of China's culture,media convergence should value the cultural uniqueness and the imbalance of the realistic problems,to reach innovation and breakthrough.

  2. Impact of European Media Education Strategies on Russian Media Education Development

    Science.gov (United States)

    Mikhaleva, Galina V.

    2015-01-01

    The article attempts to examine the impact of European media education theories and approaches on Russian media education evolution basing on a comparative analysis of Russian and European media literacy promotion strategies in the historical context. This influence resulted in the appearance and development of socio-cultural models of media…

  3. Pengembangan Media Pembelajaran Berupa Komik Fisika Berbantuan Sosial Media Instagram sebagai Alternatif Pembelajaran

    Directory of Open Access Journals (Sweden)

    Irwandani Irwandani

    2016-04-01

    Full Text Available The development trend of technology and information at this time should be used by the world of education to make it as a learning tool, both outside and inside the classroom. One trend that is emerging now is the use of social media as a medium of learning. Social media will be focused to develop is a media Instagram, in which can contain images and text content. The study was conducted with the aim of producing instructional media products that meet the necessary criteria. The research is the research and development method undertaken by several stages, a preliminary investigation, gathering information, product design, product validation, testing is limited to the user, and product revision. Based on the stages that made learning media product obtained declared fit and is needed by learners after validating and testing the product. Validation linguists gained 84%, the design of 82.67%, 86.67% materials, and media gained 87.14%. Meanwhile, based on the scoring is obtained 90.83%. Tren perkembangan teknologi dan informasi saat ini seharusnya bisa dimanfaatkan oleh dunia pendidikan untuk menjadikannya sebagai sarana pembelajaran, baik itu di luar maupun di dalam kelas. Salah satu tren yang sedang muncul saat ini adalah pemanfaatan media sosial sebagai media pembelajaran. Media sosial yang akan difokuskan untuk dikembangkan adalah media instagram, yang di dalamnya bisa memuat konten gambar dan tulisan. Penelitian dilakukan dengan tujuan menghasilkan produk media pembelajaran yang memenuhi kriteria yang dibutuhkan. Penelitian yang digunakan adalah penelitian dan pengembangan yang dilakukan dengan beberapa tahap yaitu melakukan penelitian pendahuluan, mengumpulkan informasi, desain produk, validasi produk, ujicoba terbatas kepada pengguna, kemudian revisi produk. Berdasarkan tahapan-tahapan yang dilakukan diperoleh produk media pembelajaran yang dinyatakan layak dan sangat dibutuhkan oleh peserta didik setelah melakukan validasi

  4. Optimal Full Waveform Inversion Strategy in Azimuthally Rotated Elastic Orthorhombic Media

    KAUST Repository

    Oh, Juwon

    2017-05-26

    The elastic orthorhombic assumption is one of the most practical Earth models that takes into account the horizontal anisotropic layering and vertical fracture network. In this model, the rotation angle of the vertical planes of symmetry is a crucial parameter needed to increase the convergence of an anisotropic full waveform inversion (FWI) as well as to provide the fracture geometry along azimuthal direction. As an initial step, we investigate the possibility of recovering the azimuth angle via FWI, which may offer high-resolution information. We first utilize our new parameterization with deviation parameters, which provides the opportunity for multi-stage FWI. Based on the radiation patterns and gradient directions of each parameter, we show that the azimuth angle mainly affects the parameters that have azimuth-dependent radiation patterns, so that we can hierarchically build up the subsurface model from isotropic to VTI to azimuthally rotated orthorhombic models with less trade-offs. From the numerical example for a synthetic 3D model, we expect that both a deviation parameter and the azimuth angle can be recovered in the last stage of FWI with minimum trade-offs.

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

    DEFF Research Database (Denmark)

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

    2017-01-01

    media use is changing rapidly; 15%–16% of Danish candidates used Twitter in 2011 but 68% in 2015. In this large-sample content analysis, party leaders have high traditional-news-media and low Twitter presence, and younger candidates visa-versa, but some politicians have high presence in both. Hybrid...

  6. Your Media Speak So Loud I Can't Hear a Word You're Saying: Impact of Media and Media Selection on Performance

    Science.gov (United States)

    Hassell, Martin

    2013-01-01

    With the proliferation of communication media and technologies available, it is important for teams to understand the influence of these media on the performance of their communications. Additionally, it is important for researchers to understand how teams choose and use media. Literature on communication media impacts and communication…

  7. Critical Media Literacy in Action: Uniting Theory, Practice and Politics in Media Education

    Science.gov (United States)

    Thevenin, Benjamin Joseph

    2012-01-01

    As media literacy is a growing field, there exist a number of distinct approaches to media education with varied political significance. Approaches such as protectionism, media arts education, and critical media literacy draw upon diverse theoretical traditions. Often overlooked in these traditions is the Critical Theory of the Frankfurt School.…

  8. 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.

  9. Media Anthropology: A Theoretical Framework

    Science.gov (United States)

    Eiselein, E. B.; Topper, Martin

    1976-01-01

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

  10. Potentials of Social Media as Media Facility of Tourism Promotion Based on Community Participation

    OpenAIRE

    Romadhan, Mohammad Insan; Rusmana, Dewi Sri Andika

    2018-01-01

    The potential of social media as a media of tourism promotion is vastly massive. Nevertheless, the problem is on how to get social media can be widely known and has abundant followers for the publicized content could be accepted by the crowd. Normally, social media of a tourism promotion is integrated with conventional media like television, radio and newspapers. What if a region does not have large funds to interact with the conventional media, such issue be overcome with community participa...

  11. 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.

  12. Including Media in Field Research and Becoming Part of the Science Media

    Science.gov (United States)

    Pelto, M. S.

    2015-12-01

    There are two primary strategies that I have pursued over the last decade to engage the media, policy makers, and public; after two decades of typical scientific publication methods. An effective method to engage the media with our ongoing 32 year glacier field research program has been to invite media members to join us in the field. From climate videographers to traditional reporters we have had a member of the media with us in nine of the last ten field seasons; two in 2015. The resulting stories have led to several awards for the journalists and an ongoing relationship with our research program. The second part of this science research communication strategy is to have readily available material on specific topics for the media to utilize; this requires social media outreach. The primary outlet media find is the AGU Blog: From a Glacier's Perspective. This blog pubishes two articles a week on a specific glacier's response to climate change. The blog yields on average a media contact on every fourth blog post in 2015. The contacts revolve around specific local glacier information published on the blog. The goal of each blog post is to tell a story about how each glacier is impacted by climate change.

  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...... of using open media to face the challenges of OS....

  14. Developing an Ethics of Youth Media Production Using Media Literacy, Identity, and Modality

    Science.gov (United States)

    Gibbons, Damiana

    2012-01-01

    This critical, theoretical paper conceptualizes what determines an ethics for youth media production. Through discussions of media literacy, identity, and multimodality, I attempt to shift the question away from "What are the ethical ways in which youth use media?" toward the question "What are the ethics we have created as media literacy…

  15. Transnational orientations in a global media landscape: Youth, media, war and conflict

    Directory of Open Access Journals (Sweden)

    Elisabeth Eide

    2014-04-01

    Full Text Available This article reflects on the role of media in the re-imagination and reproduction (reconstruction of Norwegian identities and communities with a particular focus on how young people within diasporas follow news on war and conflict in their (or their parents’ countries of origin. The research employs focus groups with young people from the Pakistani, Afghan, and Tamil Diasporas, and also online surveys. The three groups share the experience of trying to build a life in another country (Norway, while their family and friends in the “homeland” experience political violence and civil war. We identify a notable sense of frustration and skepticism towards Norwegian media. The informants actively use international media and media from the homeland, and often find these more reliable and providing more relevant information than Norwegian media. They also voice a strong critique of the ways in which the media react when “the others” are victims of violence, and several participants react negatively towards the neglect of positive reporting from their respective homelands, and to media hostility towards Muslims.

  16. Water Chemistry and Chemistry Monitoring at Thermal and Nuclear Power Plants: Problems and Tasks (Based on Proceedings of Conferences)

    Science.gov (United States)

    Larin, B. M.

    2018-02-01

    In late May-early June 2017, two international science and technology conferences on problems of water chemistry and chemistry monitoring at thermal and nuclear power plants were held. The participants of both the first conference held at OAO VTI and the second conference that took place at NITI formulated the problems of the development of the regulatory base and implementation of promising water treatment technologies and outlined the ways of improving the water chemistry and chemistry monitoring at TPPs and NPPs for the near future. It was pointed out that the new amine-containing VTIAMIN agent developed by OAO VTI had been successfully tested on the power-generating units equipped with steam-gas plants to establish the minimum excess of the film-forming amine in the power-generating unit circuit that ensures the protection of the metal as 5-10 μg/dm3. A flow-injection technique for the analysis of trace concentrations of chlorides was proposed; the technique applied to the condensate of the 1000-MW steam turbine of the NPP power-generating unit yields the results comparable with the results obtained by the ion chromatography and the potentiometric method using the solver electrode. The participants of the conferences were demonstrated new Russian instruments to analyze the water media at the TPPs and NPPs, including the total organic carbon analyzer and the analyzer of mineral impurities in the condensate and feed water, that won a gold medal at the 45th International Exhibition of Inventions held in Geneva this April.

  17. 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…

  18. Transport in Stochastic Media

    International Nuclear Information System (INIS)

    Haran, O.; Shvarts, D.; Thieberger, R.

    1998-01-01

    Classical transport of neutral particles in a binary, scattering, stochastic media is discussed. It is assumed that the cross-sections of the constituent materials and their volume fractions are known. The inner structure of the media is stochastic, but there exist a statistical knowledge about the lump sizes, shapes and arrangement. The transmission through the composite media depends on the specific heterogeneous realization of the media. The current research focuses on the averaged transmission through an ensemble of realizations, frm which an effective cross-section for the media can be derived. The problem of one dimensional transport in stochastic media has been studied extensively [1]. In the one dimensional description of the problem, particles are transported along a line populated with alternating material segments of random lengths. The current work discusses transport in two-dimensional stochastic media. The phenomenon that is unique to the multi-dimensional description of the problem is obstacle bypassing. Obstacle bypassing tends to reduce the opacity of the media, thereby reducing its effective cross-section. The importance of this phenomenon depends on the manner in which the obstacles are arranged in the media. Results of transport simulations in multi-dimensional stochastic media are presented. Effective cross-sections derived from the simulations are compared against those obtained for the one-dimensional problem, and against those obtained from effective multi-dimensional models, which are partially based on a Markovian assumption

  19. 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...

  20. 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...

  1. 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 ...

  2. Breaking Open the Black Boxes: media archaeology, anarchaeology and media materiality

    OpenAIRE

    Goddard, M.

    2015-01-01

    An essay on the emergent methodology of media archaeology, in realtion to the material turn in approaches to digital media. In particular, this article advocates taking up Siegfried Zielinski's concept of 'anarchaeology', but in a different sense to the way it was originally proposed, in order to emphasise the political potentials of a media (an)archaeological methodological approach.

  3. Tantangan Literasi Era Media Digital (Analisa Pengguna Media berdasarkan Model Kemungkinan Elaborasi)

    OpenAIRE

    Yudha, Reza Praditya

    2017-01-01

    Negative content is a common thing encountered in social media. Not resolved yet, precisely social media is used as reference or source by mass media. In fact, media literacy has been put into practice and exposed the dangers of negative content since long time ago. Two interesting phenomena are; negative content that predicted would be soar on Jakarta Governor Election, April 2017, was missed. Those negative content still exists, organized, even commodified nowdays. The second phenomenon, th...

  4. Brand innovation and social media: knowledge acquisition from social media, market orientation, and the moderating role of social media strategic capability

    OpenAIRE

    Nguyen, Bang; Xiaoyu, Yu; Melewar, T. C.; Chen, Junsong

    2015-01-01

    The study examines the relationships between knowledge acquisition from social media, two forms of market orientation (proactive and reactive), social media strategic capability, and brand innovation strategy in the context of China’s online technology industry. Analysis of 357 online technology ventures, created during the past 6 years, suggests that brand innovation is affected by both knowledge acquisition from social media and market orientation. Social media strategic capability positive...

  5. Media Morality and Visual Icons in the Age of Social Media

    DEFF Research Database (Denmark)

    Mortensen, Mette; Trenz, Hans-Jörg

    2016-01-01

    New and social media are increasingly used to raise issues of global justice. Images and texts representing distant suffering in an emotionally charged way involve users of social media in debates about ethical standards and moral responsibility. This raises the question of how social media users...... in fall 2015, which raised questions of distant spectatorship and moral responses with renewed urgency and immediacy. We consider the conditions of collective reception and interpretation of visual icons of human suffering, which became viral through social media in this period. We first situate social...... media reception in the framework for the analysis of moral spectatorship. We secondly explore the link between iconic images and the emergence of so-called impromptu publics of moral spectatorship. As an empirical case, we refer to the performance of reddit discussion groups in confronting the salient...

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

    Directory of Open Access Journals (Sweden)

    Viorica Pauș

    2013-05-01

    Full Text Available 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 others to share this vision. In terms of open communication, the external image of organization reflects, in part, leadership practices within the organization. It is about the exercise of the shared collective leadership (Don Tapscott, 1996 that should strengthen the organization position.

  7. Otitis media with effusion

    Science.gov (United States)

    OME; Secretory otitis media; Serous otitis media; Silent otitis media; Silent ear infection; Glue ear ... from the tube and is swallowed. OME and ear infections are connected in two ways: After most ear ...

  8. 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.

  9. Analisis Kebutuhan Terhadap Program Multi Media Interaktif Sebagai Media Pembelajaran

    OpenAIRE

    waldopo, Waldopo

    2011-01-01

    Multimedia interactive is on instructional media that combines elements of sound, visual and text, and can interact with the users. The aim of this study is to obtain information about the needs of interactive multimedia as instructional media. If needed, what kind of subjects that need to be supported by multi-media and type of format that presented. The population are students, teachers and senior secondary school principals. Sample was taken randomly. From the results of randomization assi...

  10. 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)

  11. Social media invloed en reputatie: de identificatie van invloed binnen social media

    NARCIS (Netherlands)

    Vollenbroek, Wouter Bernardus; de Vries, Sjoerd A.; Constantinides, Efthymios

    2012-01-01

    Social media is een fenomeen waarvan de waarde voor organisaties niet meer wordt betwist. Betrokken binnen het bedrijfsleven erkennen het allemaal, social media spelen een rol of gaan een grote rol spelen binnen de corporate communicatie. Van groot belang hierbij is de invloed die social media

  12. Media activism as movement?: collective identity formation in the World Forum of Free Media

    OpenAIRE

    Stephansen, Hilde C.

    2017-01-01

    More than simply tools used by social movements to reach other substantive aims, media are increasingly becoming subjects of activism. This article contributes to advancing understanding of such media-focused activism through a case study of the World Forum of Free Media, a thematic forum for media activists and media advocacy organisations linked to the World Social Forum. Based on qualitative research conducted between 2008 and 2016 -including participant observation, in-depth interviews an...

  13. Media independence and dividend policy

    DEFF Research Database (Denmark)

    Farooq, Omar; Dandoune, Salma

    2012-01-01

    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...... 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......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...

  14. MEDIA MASSA DAN RUANG PUBLIK (Analisis Perilaku Penggunaan Sosial Media dan Kemampuan Remaja dalam menulis

    Directory of Open Access Journals (Sweden)

    Juwono Tri Atmodjo

    2015-11-01

    Full Text Available Mass communication media facilitate new web-based way to send a message and the transformation of a media value to others . It appears once as the number and types of social media with an excess of the ability to express ideas, opinions, funny stories, vent arena, and the troubled space with varying terminology The procedure varies penggunaannyapun penggunaannyapun more varied behavior . The survey was to assess the use of social media by ramaja and writing skills gained from the use of social media . Based on data analysis that ; social media most used by teens are Facebook, Twitter , and Yahoo! Messenger and chat through the use of social media is often done . Respondents are not familiar with the use of blogs, SlideShare , instagram, flicker, Skype, Myspace, Friendfeed, and Fhorum . Average use of social media by teens for 3 hours per day , which is accessed through the most HP to update the status, respondents were able to express the idea/ideas and feelings in writing, listening to other people's posts , teens learn the language, able to use symbols used teen, easy of expression, described feeling depressed and juvenile writing skills by using social media .   media komunikasi massa memfasilitasi cara berbasis web untuk mengirim pesan dan transformasi nilai media untuk orang lain. Tampaknya sekali sebagai jumlah dan jenis media sosial dengan kelebihan kemampuan untuk mengekspresikan ide, pendapat, cerita lucu, arena ventilasi, dan ruang bermasalah dengan berbagai terminologi. Prosedur bervariasi penggunaannyapun penggunaannyapun perilaku yang lebih bervariasi. survei ini adalah untuk menilai penggunaan media sosial oleh ramaja dan menulis keterampilan yang diperoleh dari penggunaan media sosial. Berdasarkan analisis data yang; media sosial paling banyak digunakan oleh remaja Facebook, Twitter, dan Yahoo! Messenger dan chatting melalui penggunaan media sosial sering dilakukan. Responden tidak akrab dengan penggunaan blog, Slide

  15. 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.

  16. Media Literacy Art Education: Deconstructing Lesbian and Gay Stereotypes in the Media

    Science.gov (United States)

    Chung, Sheng Kuan

    2007-01-01

    Popular media such as films, television programmes/commercials and magazines have become the dominant source through which children learn about others and their world, develop attitudes and beliefs as manifested in media expressions, and formulate their sense of identity. Popular media have enormous influence on children who are constantly…

  17. Generalized nihility media from transformation optics

    International Nuclear Information System (INIS)

    Yan, Wei; Yan, Min; Qiu, Min

    2011-01-01

    Nihility media in the previous literature are usually understood as media with ε = μ = 0. Transformation optics opens a new perspective for capturing the essence of such media. From this perspective, we generalize the definition of nihility media as transformation media derived from volumeless geometrical elements. A volumeless geometrical elements can be either a point (P), a line (L), or a surface (S). Their corresponding transformation media are therefore called P-, L-, or S-type nihility media, respectively. The previous defined nihility media with ε = μ = 0 is a special case under the P-type nihility media. The constructions of nihility media by metamaterials are discussed. The eigenfields in different types of nihility media are derived. The interactions between an externally incident wave and a slab of nihility media in a free space background are analyzed. Furthermore, we discuss compensated bilayers composed of nihility media. It is shown that for a slab of P-type nihility media, a normally incident wave can perfectly transmit through, while all obliquely incident waves are completely blocked; for a slab made of L-type nihility media, both normally and obliquely incident waves can transmit with some reflections, which can be eliminated by adding a compensating L-type nihility media; for a slab of S-type nihility media, all field components can perfectly transmit through

  18. PERIKLANAN DALAM MEDIA BARU (Advertising In The New Media

    Directory of Open Access Journals (Sweden)

    Errika Dwi Setya Watie

    2016-03-01

    Full Text Available Advertising is currently getting a huge challenge. the number of ads , it is realized or not, effects on saturation of advertising. New era media presents new communications media to the community. This condition should be recognized by anyone working in the advertising, because the development of advertising is in line with a new media movement, so the expectansy of the intended market segment will be achieved better. Today, the challenge of a new style of advertising has been answered by the professions related to a new advertising which is driven by the appearance and the popularity of the new social media. One of the new profession known by and used in advertising is a Buzzer. The principle work of Buzzer is similar to WOM (Word Of Mouth. However, it should also be remembered that the selection of buzzer is also important, so that the purpose of advertising can be achieved.

  19. Media Art

    DEFF Research Database (Denmark)

    Ekman, Ulrik

    2015-01-01

    environments, experience time, and develop identities individually and socially. Interviews with working media artists lend further perspectives on these cultural transformations. Drawing on cultural theory, new media art studies, human-computer interaction theory, and software studies, this cutting-edge book...... critically unpacks the complex ubiquity-effects confronting us every day....

  20. Mainstream Media and Social Media Reactions to the Discovery of Extraterrestrial Life

    Science.gov (United States)

    Jones, Morris

    The rise of online social media (such as Facebook and Twitter) has overturned traditional top-down and stovepiped channels for mass communications. As social media have risen, traditional media sources have been steadily crippled by economic problems, resulting in a loss of capabilities and credibility. Information can propagate rapidly without the inclusion of traditional editorial checks and controls. Mass communications strategies for any type of major announcement must account for this new media landscape. Scientists announcing the discovery of extraterrestrial life will trigger a multifaceted and unpredictable percolation of the story through the public sphere. They will also potentially struggle with misinformation, rumours and hoaxes. The interplay of official announcements with the discussions of an extraterrestrial discovery on social media has parallels with traditional theories of mass communications. A wide spectrum of different messages is likely to be received by different segments of the community, based on their usage patterns of various media and online communications. The presentation and interpretation of a discovery will be hotly debated and contested within online media environments. In extreme cases, this could lead to "editorial wars" on collaborative media projects as well as cyber-attacks on certain online services and individuals. It is unlikely that a clear and coherent message can be propagated to a near-universal level. This has the potential to contribute to inappropriate reactions in some sectors of the community. Preventing unnecessary panic will be a priority. In turn, the monitoring of online and social media will provide a useful tool for assessing public reactions to a discovery of extraterrestrial life. This will help to calibrate public communications strategies following in the wake of an initial announcement.

  1. 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.

  2. New Media, New Citizens?

    DEFF Research Database (Denmark)

    Ohme, Jakob

    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...

  3. Media and manipulation

    Directory of Open Access Journals (Sweden)

    Kovačević Braco

    2013-01-01

    Full Text Available The role and importance of the media are huge, both in everyday life and in cultural, spiritual and political life of modern man. Their power in the sense of political shaping of people and shaping of public opinion is very distinctive. In the process of propaganda to influence public opinion, they use various manipulative procedures in order to accomplish certain interests and objectives. Through the media, politics realizes its economic, ideological, political and even military activities. The war in the former Yugoslavia and former Bosnia and Herzegovina was also waged through the media. This media war still is spreading the hate speech, thus still causing conflicts and disintegration processes in the Balkans.

  4. Operationalizing Social Media: A Method For Incorporating Social Media In Department Of Defense Plans

    Science.gov (United States)

    2018-04-20

    consumer, and includes word -of- mouth or viral posts.7 However, the marketer may help generate earned media through marketing actions.8 Likewise, earned... MEDIA : A METHOD FOR INCORPORATING SOCIAL MEDIA IN DEPARTMENT OF DEFENSE 5b. GRANT NUMBER PLANS 5c. PROGRAM ELEM ENT NUMBER 6. AUTHOR(S) 5d. PROJECT... social media to influence the 2016 U.S. presidential elections demonstrated the power of social media . They also revealed that the U.S. is behind its

  5. 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.

  6. Prosocial effects of media.

    Science.gov (United States)

    Hogan, Marjorie J

    2012-06-01

    Parents, teachers, health care providers, and other caring adults worry about the harmful influence of media messages and images on children and teens and wonder how to recognize and encourage positive and healthy use of media. For decades, experts have commented on the power of media. Media depictions can lead to negative attitudes and behavior in some young viewers. This article discusses whether prosocial, tolerant, and cooperative attitudes and behavior can be learned and imitated by children and adolescents and whether media can nurture or stimulate creativity or actively promote health and well-being in young consumers. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. 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.

  8. 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...

  9. Communicating Ebola through social media and electronic news media outlets: A cross-sectional study.

    Science.gov (United States)

    Househ, Mowafa

    2016-09-01

    Social media and electronic news media activity are an important source of information for the general public. Yet, there is a dearth of research exploring the use of Twitter and electronic news outlets during significant worldly events such as the recent Ebola Virus scare. The purpose of this article is to investigate the use of Twitter and electronic news media outlets in communicating Ebola Virus information. A cross-sectional survey of Twitter data and Google News Trend data from 30 September till 29 October, 2014 was conducted. Between 30 September and 29 October, there were approximately 26 million tweets (25,925,152) that contained the word Ebola. The highest number of correlated activity for Twitter and electronic news outlets occurred on 16 October 2014. Other important peaks in Twitter data occurred on 1 October, 6 October, 8 October, and 12 October, 2014. The main influencers of the Twitter feeds were news media outlets. The study reveals a relationship between electronic news media publishing and Twitter activity around significant events such as Ebola. Healthcare organizations should take advantage of the relationship between electronic news media and trending events on social media sites such as Twitter and should work on developing social media campaigns in co-operation with leading electronic news media outlets (e.g. CNN, Yahoo, Reuters) that can have an influence on social media activity. © The Author(s) 2015.

  10. Update on Otitis Media in Children.

    Science.gov (United States)

    Schoem, Scott R.

    1997-01-01

    This article discusses otitis media in children. It addresses risk factors for otitis media, pathogenesis, diagnosis, bacteria causing otitis media, and treatment for acute otitis media, recurrent acute otitis media, and persistent otitis media with effusion, including antibiotics, steroids, allergy control, autoinflation, mechanical ventilation,…

  11. Media preparation and bacteriological tools.

    Science.gov (United States)

    Elbing, Karen; Brent, Roger

    2002-08-01

    Recipes are provided in this unit for minimal liquid media, rich liquid media, solid media, top agar, and stab agar. Also included are descriptions and useful information about tools used with growth media such as inoculating loops, sterile toothpicks and spreaders.

  12. Merancang Media Hiburan Buku Cergam Menjadi Media Belajar untuk Alat Bantu Komunikasi

    Directory of Open Access Journals (Sweden)

    Ida Nurhaida

    2007-06-01

    Full Text Available For the sake of reinforcing the local knowledge (that seems to be abandoned by local community of West Lampung themselves and to make corrections against agroforestry malpractices as well as of accommodating to the poor performance of extension programs on recharge area of West Lampung (including of media lacking of extension, we have developed the entertainment media of pictorial story books of coffee agroforestry. The media were designed especially for the low literate community (Nurhaida et al., 2004 to affirm the tao of knowledge of the four tribes dwell in the recharge area: Lampungese, Semendonese, Sundanese and Sundanese of villages of Way Mengaku, Sukananti, Sidomakmur and Gunung Terang respectively (see Nurhaida et al., (2005. There are four languages edition in accordance with the locally mother tongues of the four tribes plus Indonesian to accommodate the other tribes exist in West Lampung. Desk activities were conducted at the Laboratory of Multimedia, Departmentof Communication Science, The University of Lampung Indonesia. Media pretesting were conducted twice in August-September 2005 to measure the variables of attraction, self involvement, acceptability and comprehension of the media in accordance with Bertrand’s suggestion (1978. Between the two and the second of the media pretesting, there had been conducted the media improvements. The research showed that the entertainment media have been used up to be a learning media for the propose of extension program in the recharge area successfully. This claim is supported by the high effectiveness of the five editions: (Lampungese, Semendonese, Javanese, Sundanese and Indonesian of 85, 89, 88, 89, and 86% repectively that brookthrough aggaints the severely heavied barrier of low litteracy : 27, 44, 39, 77, dan 88 words per second respectively. It is strongly recommended that: (1 reproduce the media and disseminate into community dwell on the recharge of West Lampung to reinforce the

  13. Sinusitis with eosinophilic otitis media

    International Nuclear Information System (INIS)

    Kawano, Toshiro; Ishitoya, Junichi; Tsukuda, Mamoru

    2007-01-01

    Eosinophilic otitis media is an intractable inflammation of the middle ear combined with bronchial asthma. According to a national epidemiological investigation on eosinophilic otitis media, it is assumed that eosinophilic otitis media are combined with sinusitis in about 74% of their cases. On the other hand, organizational images of eosinophilic otitis media and eosinophilic sinusitis are similar, and steroid therapy is effective together, and it is thought that they are involved in the idea of one airway one disease, but the details of sinusitis combined with the eosinophilic otitis media are unidentified. Therefore, we examined the kinds of the sinusitis combined with eosinophilic otitis media. We diagnosed 18 cases (male: 2 cases, female: 16 cases) (average age: 54.6 years old) as eosinophilic otitis media according to the diagnostic criteria. And, by the CT views of a paranasal sinus, blood tests, existence of the nasal polyp, etc, we investigated the kinds of sinusitis combined with eosinophilic otitis media. It turned out that bronchial asthma was combined with eosinophilic otitis media in 17 of 18 cases (airway hypersensitivity did sthenia of one case, but the asthma did not yet developed), and 6 cases were combined with aspirin induced asthma (AIA), and 3 cases were combined with Churg-Strauss syndromes (CSS). 10 case (55.6%) of 17 eosinophilic otitis media were combined with eosinophilic sinusitis. And 4 cases (22.2%) of 17 eosinophilic otitis media were combined with chronic sinusitis, 4 cases (22.2%) of 17 eosinophilic otitis media were not combined with sinusitis. We concluded that eosinophilic otitis media was not always combined with eosinophilic sinusitis. The idea of one airway one disease was not applied to this examination. (author)

  14. Sinusitis with eosinophilic otitis media

    Energy Technology Data Exchange (ETDEWEB)

    Kawano, Toshiro; Ishitoya, Junichi [Yokohama City Univ., Medical Center, Yokohama, Kanagawa (Japan); Tsukuda, Mamoru [Yokohama City Univ., Graduate School of Medicine, Yokohama, Kanagawa (Japan)

    2007-09-15

    Eosinophilic otitis media is an intractable inflammation of the middle ear combined with bronchial asthma. According to a national epidemiological investigation on eosinophilic otitis media, it is assumed that eosinophilic otitis media are combined with sinusitis in about 74% of their cases. On the other hand, organizational images of eosinophilic otitis media and eosinophilic sinusitis are similar, and steroid therapy is effective together, and it is thought that they are involved in the idea of one airway one disease, but the details of sinusitis combined with the eosinophilic otitis media are unidentified. Therefore, we examined the kinds of the sinusitis combined with eosinophilic otitis media. We diagnosed 18 cases (male: 2 cases, female: 16 cases) (average age: 54.6 years old) as eosinophilic otitis media according to the diagnostic criteria. And, by the CT views of a paranasal sinus, blood tests, existence of the nasal polyp, etc, we investigated the kinds of sinusitis combined with eosinophilic otitis media. It turned out that bronchial asthma was combined with eosinophilic otitis media in 17 of 18 cases (airway hypersensitivity did sthenia of one case, but the asthma did not yet developed), and 6 cases were combined with aspirin induced asthma (AIA), and 3 cases were combined with Churg-Strauss syndromes (CSS). 10 case (55.6%) of 17 eosinophilic otitis media were combined with eosinophilic sinusitis. And 4 cases (22.2%) of 17 eosinophilic otitis media were combined with chronic sinusitis, 4 cases (22.2%) of 17 eosinophilic otitis media were not combined with sinusitis. We concluded that eosinophilic otitis media was not always combined with eosinophilic sinusitis. The idea of one airway one disease was not applied to this examination. (author)

  15. Meme media and meme market architectures knowledge media for editing distributing and managing intellectual resources

    CERN Document Server

    Tanaka, Y

    2003-01-01

    "In this book, Yuzuru Tanaka proposes a powerful new paradigm: that knowledge media, or "memes," operate in a way that closely resembles the biological function of genes, with their network publishing repository working as a gene pool to accelerate the evolution of knowledge shared in our societies. In Meme Media and Meme Market Architectures: Knowledge Media for Editing, Distributing, and Managing Intellectual Resources, Tanaka outlines a ready-to-use knowledge media system, supplemented with sample media objects, which allows readers to experience the knowledge media paradigm."--Jacket.

  16. 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

  17. 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

  18. 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...

  19. Organizational Communication and Media

    DEFF Research Database (Denmark)

    Tække, Jesper

      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...... 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...... 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...

  20. 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

  1. Numerical simulation in applied geophysics

    CERN Document Server

    Santos, Juan Enrique

    2016-01-01

    This book presents the theory of waves propagation in a fluid-saturated porous medium (a Biot medium) and its application in Applied Geophysics. In particular, a derivation of absorbing boundary conditions in viscoelastic and poroelastic media is presented, which later is employed in the applications. The partial differential equations describing the propagation of waves in Biot media are solved using the Finite Element Method (FEM). Waves propagating in a Biot medium suffer attenuation and dispersion effects. In particular the fast compressional and shear waves are converted to slow diffusion-type waves at mesoscopic-scale heterogeneities (on the order of centimeters), effect usually occurring in the seismic range of frequencies. In some cases, a Biot medium presents a dense set of fractures oriented in preference directions. When the average distance between fractures is much smaller than the wavelengths of the travelling fast compressional and shear waves, the medium behaves as an effective viscoelastic an...

  2. Illicit drugs and the media: models of media effects for use in drug policy research.

    Science.gov (United States)

    Lancaster, Kari; Hughes, Caitlin E; Spicer, Bridget; Matthew-Simmons, Francis; Dillon, Paul

    2011-07-01

    Illicit drugs are never far from the media gaze and although identified almost a decade ago as 'a new battleground' for the alcohol and other drug (AOD) field there has been limited research examining the role of the news media and its effects on audiences and policy. This paper draws together media theories from communication literature to examine media functions. We illustrate how each function is relevant for media and drugs research by drawing upon the existing literature examining Australian media coverage during the late 1990s of escalating heroin-related problems and proposed solutions. Media can influence audiences in four key ways: by setting the agenda and defining public interest; framing issues through selection and salience; indirectly shaping individual and community attitudes towards risk; and feeding into political debate and decision making. Each has relevance for the AOD field. For example, media coverage of the escalating heroin-related problems in Australia played a strong role in generating interest in heroin overdoses, framing public discourse in terms of a health and/or criminal issue and affecting political decisions. Implications AND CONCLUSION: Media coverage in relation to illicit drugs can have multifarious effects. Incorporating media communication theories into future research and actions is critical to facilitate understanding of the short- and long-term impacts of media coverage on illicit drugs and the avenues by which the AOD field can mitigate or inform future media debates on illicit drugs. © 2010 Australasian Professional Society on Alcohol and other Drugs.

  3. New media, old media: The technologies of international development

    Science.gov (United States)

    Ingle, Henry T.

    1986-09-01

    The research, theory and practice of educational technology over the past 75 years provide convincing evidence that this process offers a comprehensive and integrated approach to solving educational and social problems. The use of media and technology in development has shifted from an emphasis on mass media to personal media. A variety of electronic delivery systems are being used and are usually coordinated by centralized governmental agencies. There are no patterns of use since the problems vary and the medium used is responsive to the problem. Computers are used most frequently and satellite telecommunication networks follow. The effective use of these and other technologies requires a long-term commitment to financial support and training of personnel. The extension model of face-to-face contact still prevails in developing nations whether in agriculture, education or rural development. Low-cost technologies are being used in local projects while major regional and national companies use radio, film and related video technologies. The use of all available and cost-effective media and technologies make possible appropriate communications for specific goals with specific audiences. There appears to be no conflict among proponents of various media formats. Development in education and other sectors has much to gain from old and new communication technologies and has hardly been tapped. Several new educational technology developments are discussed as potential contributors to formal and nonformal education.

  4. Media, journalism, objectivity

    Directory of Open Access Journals (Sweden)

    Vlajki Emil

    2013-01-01

    Full Text Available This is the text around the themes: Media and Journalism, are confronted two directions of opinions: humanism and elitism. Humanism believes that media and journalism must be metaphysically objective: able to tell the truth regardless of time, place and terms of events. Another approach, elitism, is connected with Hegel's philosophy of history. Hegel's conceptual apparatus includes: Idea, History dialectic, 'cunning mind,' self- development and self-realization. In this context, media and journalism are considered as organic unity, an inseparable part of some dialectical totality. More specifically media and journalism can be objective only if they defend concrete ideological assumptions of society to which they belong. Any other understanding of these two concepts is non-objective, mere moralizing and / or demagoguery.

  5. Social Media Policies

    DEFF Research Database (Denmark)

    Stohl, Cynthia; Etter, Michael; Banghart, Scott

    2017-01-01

    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...... policies represent a relatively unrecognized development in the institutionalization of CSR communicative norms and practices that call into question the promising affordances of social media for the inclusion of various voices in the public negotiation of what constitutes corporate social responsibility....

  6. The adoption of social media and social media marketing by dentists in South Africa.

    Science.gov (United States)

    Snyman, L; Visser, J H

    2014-07-01

    The purpose of the study was to identify and understand social media usage behaviour of dentists in South Africa, in general and in particular as part of their marketing strategy and to consider the potential determinants associated with these behaviours. Dentists who are members of the South African Dental Association were requested to anonymously complete an online questionnaire. Apart from demographic information, respondents were asked to report on their use of social media and their adoption of social media marketing. One-on-one interviews were also conducted with three dentists, to gain a deeper understanding of their adoption of this marketing option. South African dentists have started to embrace social media and 50.2% interact through these channels at least once a day. The most popular social media platforms are GooglePlus and Facebook. Respondents use social media mainly for personal purposes, including staying connected to family and friends.. Only 13.2% of those responding currently use social media as a marketing tool, but the majority (83.5%) predict that such usage will increase in future. Social media marketing is a growing trend and will become more significant in future. Although respondents used social media regularly for personal purposes, most are only now starting to use it as a marketing tool.

  7. Skills and Strategies for Media Education.

    Science.gov (United States)

    Thoman, Elizabeth

    1999-01-01

    To thrive in our media-saturated culture, children must become media literate and learn five lessons: media messages are constructed by a few for the many; constructions involve creative languages; different people experience the same media message differently; media are primarily profit-driven businesses; and media have embedded values and…

  8. 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

  9. 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...

  10. 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

  11. Disruptive media technologies : theories and application to the Czech media environment

    OpenAIRE

    Kyjonková, Petra

    2010-01-01

    Diploma thesis "Disruptive media technologies - theories and application to the Czech media environment" deals with a concept of disruptive technologies, which results from the economical model of creative destruction made by founder of innovation theories Joseph Alois Schumpter. Although he had described adverse impact on present market structure at the beginning of 20th century, media studies revealed them lately, precisely in the year 1995 in an economical model of another economist Clayto...

  12. Instructional Media

    African Journals Online (AJOL)

    This can be summed up in a few words: Students can learn a great deal from any of the media. Under most of the conditions tested, they could learn as much as from ... Beyond physical conditions (deafness) there is little reason to expect a differential media. Scientia Militaria, South African Journal of Military Studies, Vol 13 ...

  13. Mixed Media

    Science.gov (United States)

    Peterson, Erin

    2010-01-01

    While institutions do not often have a hook as compelling as an eagerly awaited movie, great content is critical for media relations success--and coupling it with the right distribution channel can ensure the story finds the right audience. Even better, retooling it for several media platforms can extend the life and reach of a story. The changes…

  14. How to adjust media recommendations on reporting suicidal behavior to new media developments

    NARCIS (Netherlands)

    Malony, J.; Pfuhlmann, B.; Arensman, E.; Coffey, C.; Gusmão, R.; Poštuvan, V.; Scheerder, G.; Sisask, M.; van der Feltz, C.M.; Hegerl, U.; Schmidtke, A.

    2014-01-01

    This study examines the inclusion of preventive factors and new media developments in media recommendations on suicide reporting. Of the 193 member states of the United Nations screened for media recommendations, information was available for 74 countries. Similarities and differences in their

  15. 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.

  16. Haters Phenomena in Social Media

    OpenAIRE

    Pradipta, Angga; Lailiyah, S.Sos, M.I.Kom, Nuriyatul

    2016-01-01

    Social media is internet-basic media, functioned as interaction media room based on multimedia technology. And social media created some effects. One of the negative effects of social media is haters phenomena. Haters are a person who easily said dirty words, harass, and humiliate to others. This phenomena causes anxiety—especially in Indonesia, even the Government issued public policy and letter of regulation about this phenomena, through Paragraph 27 verse (3) IT Constitution, Paragraph 45 ...

  17. 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...

  18. 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.

  19. Parents of preschoolers: expert media recommendations and ratings knowledge, media-effects beliefs, and monitoring practices.

    Science.gov (United States)

    Funk, Jeanne B; Brouwer, Jason; Curtiss, Kathleen; McBroom, Evan

    2009-03-01

    Given the increase in screen media targeted at the very young, the purpose of this study was to examine preschooler parents' knowledge about expert recommendations for young children's screen media experience, their knowledge of specific screen media ratings, their beliefs about screen media effects, and actual monitoring practices. Parents of 94 children education, age and gender of child, and parents' perceptions of their child's favorite television show and favorite video or computer game. Eleven multiple-choice questions assessed the respondent's knowledge of expert recommendations for screen media for preschoolers and the meaning of television and video game content ratings. Fourteen questions addressed the typical amount of their preschooler's screen media exposure, parental rules regarding screen media use, and parents' beliefs about appropriate use of screen media for preschoolers. Preschoolers were exposed to an average of approximately 12 hours of screen media in a typical week. Parents believe that media do have either short- or long-term effects on preschoolers. Performance on factual questions was poor (mean score: 2.83 of 11). In particular, only 34% of the parents correctly identified the expert recommendation for children >2 years of age. Parents should continue to be educated about the need for preschoolers to participate in activities that promote language development, socialization, imagination, and physical activity. Although professionals should work to improve the ratings, and ultimately to implement a universal ratings system for all screen media, parents need to be encouraged to improve their understanding of current recommendations for screen media exposure and television and video game ratings.

  20. 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...

  1. Boomers versus Millennials: Online Media Influence on Media Performance and Candidate Evaluations

    Directory of Open Access Journals (Sweden)

    Terri Towner

    2016-09-01

    Full Text Available Facebook posts, YouTube videos, tweets and wooing political bloggers have become standard practice in marketing political campaigns. Research has demonstrated the effect of new media on a host of politically-related behavior, including political participation, knowledge acquisition, group formation and self-efficacy. Yet, issues related to media trust, media performance and candidate evaluations have not been fully explored. In addition, much of the political marketing research looks exclusively at the Millennial age cohort, ignoring other age groups, particularly Baby Boomers. This case study addresses whether attention to traditional (i.e., television, hard-copy newspapers and radio and online media sources (i.e., political candidate websites, television network websites, online newspapers, Facebook, Twitter, YouTube, Tumblr and political blogs about the 2012 U.S. presidential campaign influences Millennials and Baby Boomers’ media trust and performance ratings, as well as candidate evaluations. Panel surveys were completed by both age cohorts, Millennials (n = 431 and Baby Boomers (n = 360, during the last two weeks of the presidential election. Findings indicate that traditional sources, specifically television, rather than online sources are significantly linked to media trust and performance ratings among both Boomers and Millennials. Attention to traditional media for campaign information predicts Boomers’ candidate evaluations, whereas Millennials’ candidate evaluations are influenced by online sources, such as Facebook and candidate websites.

  2. 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

  3. Negotiated media effects. Peer feedback modifies effects of media's thin-body ideal on adolescent girls.

    Science.gov (United States)

    Veldhuis, Jolanda; Konijn, Elly A; Seidell, Jacob C

    2014-02-01

    The present study introduces a theoretical framework on negotiated media effects. Specifically, we argue that feedback of peers on thin-body ideal media images and individual dispositions guide effects on adolescent girls' psychosocial responses to media exposure. Therefore, we examined the thin-body ideal as portrayed in media and peers' feedback on such thin-ideal images in their combined effects on adolescent girls' body dissatisfaction, objectified body consciousness, and social comparison with media models. Hence, media models and peer comments were systematically combined as incorporated entities in YouTube-formats. Hypotheses were tested in a 3 (media models: extremely thin vs. thin vs. normal weight)×3 (peer comments: 6kg-underweight vs. 3kg-underweight vs. normal-weight)×2 (appearance schematicity: lower vs. higher) between-subjects design (N=216). Results showed that peer comments indicating that a media model was 'only 3kg-underweight' exerted most negative responses, particularly in girls who strongly process appearance relevant information. Peer feedback interacts with media models in guiding perceptions of what is considered an 'ideal' body shape. Results highlight the important role of peers as well as individual predispositions in view of understanding how thin-ideal media images may impact adolescent girls' body image concerns. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. DISCOURSE ANALYSIS OF JLO COMPANY ESTABLISHMENT ISSUE IN ONLINE MEDIA AND MEDIA RELATIONS TREATMENT OF JASA MARGA COMPANY (ANALISIS WACANA ISU PENDIRIAN PT. JLO DI MEDIA ONLINE DAN TREATMENT MEDIA RELATIONS PT. JASA MARGA

    Directory of Open Access Journals (Sweden)

    Icha Bella Widawati

    2017-02-01

    Full Text Available Abstract. discourse Analysis of Coverage in the Online Media Liputan6.com. Regarding to Establishment Issue of New Subsidiary PT. Jasa Layanan Operasi ( PT . JLO . The research is about coverage analysis to see the implementatiom issue management through me-dia relations activations at online media by Jasa Marga’s Public Relations Officer. This study aims to determine the discourse analysis of coverage regarding to establishment issue of new subsidiary PT. JLO in the online media and to see how Jasa Marga’s public relations of-ficer exercises issue management through media relations activations to handle the issues. Using the discourse analysis method with Halliday model of analysis. The results showed that the discourse in the news are based on fact that really happened. News content is served with a different point of view and very objective. The Media shows its position as a netral posi-tion between two sides of subjects, objective, and reporting the truth to the public. it shows that media relations activations is not bring much influence to the emerging issues and nega-tive news in the media. The conclusion of this study is the coverage was experiencing news balance between negative tone and positive tone after PRO did the media relations activations. But does not eliminate the negative news regarding the issue of the establish-ment of a subsidiary JLO. Abstrak. artikel ini merupakan sebuah analisis wacana pemberitaan di Media Online Liputan6.com mengenai Isu Pendirian Anak Usaha Baru PT. Jasa Layanan Operasi (PT. JLO serta melihat Implementasi Manajemen Isu Melalui Media Relations pada Media Online yang Dilakukan Oleh Humas Jasa Marga dengan. Penelitian ini bertujuan untuk menge-tahui analisis wacana dari Informasi pemberitaan mengenai isu pendirian anak usaha baru Jasa Marga, PT. Jasa Layanan Operasi (JLO di media online Liputan6.com dan melihat bagaimana manajemen isu melalui kegiatan media relations dilakukan untuk mengatasi isu

  5. Subjective Evaluation of Media Content as a Moderator of Media Effects on European Identity: Mere Exposure and the Hostile Media Phenomenon

    Directory of Open Access Journals (Sweden)

    Waqas Ejaz

    2017-05-01

    Full Text Available This paper posits that the concept of European identity is an important indicator of the legitimacy of the European Union (EU. It further assumes that the exposure to EU related media content can influence the feeling of European identity. In order to verify this assumption, we combined the mere-exposure-theory and the hostile media phenomenon. We assume that these theoretical concepts could help to understand the influence of media on people’s levels of attachment to the EU. Regression analyses are performed on secondary data that were collected in a Eurobarometer survey in 2013. Our findings revealed that media exposure affected the respondents’ identification with Europe, as well as the modifications of this effect based on their assessments of EU media coverage. The results of the current study not only validate assumptions about the mere-exposure effects on identity but also confirm the theoretical assumption that perceived hostility reduces such effects, whereas exposure to information that is perceived as neutral promotes the effects of media exposure on the feeling of European identity.

  6. 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,…

  7. Spontaneous Hedonic Reactions to Social Media Cues.

    Science.gov (United States)

    van Koningsbruggen, Guido M; Hartmann, Tilo; Eden, Allison; Veling, Harm

    2017-05-01

    Why is it so difficult to resist the desire to use social media? One possibility is that frequent social media users possess strong and spontaneous hedonic reactions to social media cues, which, in turn, makes it difficult to resist social media temptations. In two studies (total N = 200), we investigated less-frequent and frequent social media users' spontaneous hedonic reactions to social media cues using the Affect Misattribution Procedure-an implicit measure of affective reactions. Results demonstrated that frequent social media users showed more favorable affective reactions in response to social media (vs. control) cues, whereas less-frequent social media users' affective reactions did not differ between social media and control cues (Studies 1 and 2). Moreover, the spontaneous hedonic reactions to social media (vs. control) cues were related to self-reported cravings to use social media and partially accounted for the link between social media use and social media cravings (Study 2). These findings suggest that frequent social media users' spontaneous hedonic reactions in response to social media cues might contribute to their difficulties in resisting desires to use social media.

  8. DIGITALIZATION AND NEW MEDIA LANDSCAPE

    OpenAIRE

    Tadej Praprotnik

    2016-01-01

    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 import...

  9. Seeds of Cross-Media Production

    DEFF Research Database (Denmark)

    Bødker, Susanne; Petersen, Anja Bechmann

    2007-01-01

    separately and of cross-media production. Since cross-media production is in the making, we study the instruments currently used for planning and coordination, and analyze them as seeds that will eventually make cross-media production happen. Time and timing are important in news production in general......We present an empirical study of an organization that has recently moved from traditional newspaper production towards cross-media production involving the integrated digital production of newspaper, television, radio and web-news. The paper focuses on the daily production rhythms of the media...... with planning and coordination. We demonstrate how the production rhythms of the individual media collide with that of cross-media, and how product lifecycle rhythms add to the list of causes of problems that may jeopardize crossmedia production. We propose to strengthen planning and overview support elements...

  10. 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...

  11. 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.

  12. Media Education: Sociology Surveys

    Science.gov (United States)

    Fedorov, Alexander

    2007-01-01

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

  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. Experiences of Facebook among media students in northern Sweden:living in a social media culture

    OpenAIRE

    Juntti-Henriksson, Ann-Kristin

    2013-01-01

    University students enrolled on the “Media and communication program” in northern Sweden have been interviewed regarding their use of social media. By examining the resulting narratives through approaching poststructuralism, the study put emphasis on how the media students think and feel about their use of Facebook. Media students are heavy Facebook users who spend many hours on the social network. As future professional workers in the media industry they have a multidimensional interest in s...

  15. Komunikasi Politik di Era Media Sosial

    OpenAIRE

    Anshari, Faridhian

    2016-01-01

    The development of communication technology has penetrated the lives of human beings. One form of communication is the development of new media technologies who gave birth to social media. Political world is also not free from the influence of new media and social media. Social media are like two sides of a coin for political actors. On the one hand, the success by using social media is getting positive support. But on the other hand failure by using social media is the risk by damaging the i...

  16. 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...... avenues for a bottom-up approach incorporating a more personal knowledge management dimension, which could be synergized into collective knowledge using the social-collaborative dimension of social media. This article addresses the following questions: (1) How can social media support the management...... of personal and collective knowledge using a synergetic approach? (2) Do the personal and collective dimensions compete with each other or can they reinforce each other in a more effective manner using social media? Our findings indicate that social media supports both the personal and collective dimensions...

  17. A new approach to determine geomechanical parameters of Vertical Transverse Isotropic media using VSP data

    Science.gov (United States)

    Gholami, Raoof; Moradzadeh, Ali; Rasouli, Vamegh; Hanachi, Javid

    2014-12-01

    Conventionally, high frequency Dipole Shear sonic Imager (DSI) logs are used for anisotropic modeling where fast and slow shear wave's velocities are required. However, the results obtained from a DSI log are restricted to a specific and possibly short interval of the wellbore. The aims of this paper are to use Vertical Seismic Profile (VSP) data and show its application in geomechanical analysis of subsurface layers under anisotropic condition. After processing and separating upgoing and downgoing P- and S-waves, a methodology based Vertical Transverse Isotropic (VTI) condition was presented to determine elastic stiffness parameters. Having stiffness parameters determined, elastic modulus, strength and in-situ stress parameters were estimated and calibrated against the field and core sample data. Although the VSP based geomechanical parameters were calibrated against the real field data, the accuracy of the method cannot be as much as that of the well logs. However, the method presented in this paper may become a very good asset for geomechanical evaluation of the intervals where well log data are not available.

  18. 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

  19. Russian Media Educators: Case Studies Portraits

    Directory of Open Access Journals (Sweden)

    Alexander Fedorov

    2013-01-01

    Full Text Available This article is devoted to case studies of the media education works of some well knowns Russian media educators. The analysis of media educational work of the famous Russian media educators leads us to the conclusion that media education in Russia is developing, building on the synthesis of the aesthetic, socio-cultural, and practical concepts, with a focus on the development of media competence of the audience, mainly school and youth. The enthusiasts of media education, even devoid of substantial public support for its innovative projects, achieve significant and meaningful results.

  20. Propagation of Love waves in an elastic layer with void pores

    Indian Academy of Sciences (India)

    The paper presents a study of propagation of Love waves in a poroelastic layer resting over a poro-elastic half-space. Pores contain nothing of mechanical or energetic significance. The study reveals that such a medium transmits two types of love waves. The first front depends upon the modulus of rigidity of the elastic ...

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

    Science.gov (United States)

    Vickers, Richard; Field, James; Melakoski, Cai

    2015-01-01

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

  2. Cyberbullying dalam Media Sosial Anak SMP

    Directory of Open Access Journals (Sweden)

    Damara Putra Prasadana

    2018-02-01

    Full Text Available This paper explains about new media and cyberbullying, how teenagers use social media. Social media used by who wants to find important information. This research is aimed to analyze and describe the existence of cyberbullying among teenagers, and what causes them to do the activity in social media. The data collection used indepht interview to a suspected target. The suspected did not know the different between real behavior and mass media behavior. The result shows a characteristic of cyberbullying behaviour among teenagers. Makalah ini menjelaskan tentang media baru dan cyberbullying, bagaimana remaja gunakan media sosial Media sosial yang digunakan oleh siapa yang ingin ditemukan penting informasi. Penelitian ini bertujuan untuk menganalisis dan mendeskripsikan keberadaan penindasan maya di kalangan remaja, dan apa yang menyebabkan mereka melakukan aktivitas di media sosial. Pengambilan data menggunakan wawancara indera dengan yang dicurigai target. Yang dicurigai tidak tahu perbedaan antara perilaku nyata dan perilaku media massa Hasilnya menunjukkan karakteristik cyberbullying perilaku di kalangan remaja

  3. Social Media in IS Literature

    DEFF Research Database (Denmark)

    Dyrby, Signe

    2013-01-01

    The phenomenon of ‘digital living’ is to a high extent influenced by the introduction of new media into society. Especially, social media are affecting the digital world of today and are setting the agenda for social connectedness in private, public and commercial networks. Based in an initial...... desire to explore a research agenda for the workings of social media in network structures a look into the literature on social media within the field of Information Systems sparked an interest in exploring a new research perspective for social media. Reviewing the IS literature it is apparent...... that the perspective of the ‘media’ as an artifact of social media has been neglected in existing literature. Based in this, this paper proposes research possibilities for investigating the ‘media’ of social media as well as some theoretical considerations that could aid the investigation. Finally, potential outcomes...

  4. A Collaborative Media Production Project on Human Rights: Bridging Everyday and Media Education

    Science.gov (United States)

    Haydari, Nazan; Kara, Mustafa

    2015-01-01

    Given the importance of media institutions and universities as spaces of knowledge productions, development of "critical media pedagogy" becomes crucial for the establishment of a responsible and ethical media environment. Drawing from the collaborative project of The First Step into Human Rights: I do not do it!--A Short Film Project on…

  5. 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 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...

  6. 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...

  7. Boomers versus Millennials: Online Media Influence on Media Performance and Candidate Evaluations

    OpenAIRE

    Terri Towner; Caroline Lego Munoz

    2016-01-01

    Facebook posts, YouTube videos, tweets and wooing political bloggers have become standard practice in marketing political campaigns. Research has demonstrated the effect of new media on a host of politically-related behavior, including political participation, knowledge acquisition, group formation and self-efficacy. Yet, issues related to media trust, media performance and candidate evaluations have not been fully explored. In addition, much of the political marketing research looks exclusiv...

  8. Media and Public Communications Policies: An Empirical Analysis of the Brazilian Print Media

    Directory of Open Access Journals (Sweden)

    Guilherme Canela

    2007-12-01

    Full Text Available This essay examines a subject rarely emphasized in the studies on public interest issues reported in the print media. Drawing on a review of the journalistic content produced by 53 newspapers from every state in the federation and 4 national weekly magazines, the paper analyzes a sample of 1,184 articles, editorials, columns, interviews, and reports on subjects of immediate interest to the media, journalism, and/or media companies. Throughout 2003, 2004, and 2005, news pieces were compiled containing keywords, including “media and democracy,” “concentration of ownership,” “television regulation.” The analysis found that the print media provides insufcient and inadequate coverage of these issues, reserving more extensive coverage only to those questions nearest and dearest to it, such as the freedom of expression.

  9. 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.

  10. Does Media Literacy Mitigate Risk for Reduced Body Satisfaction Following Exposure to Thin-Ideal Media?

    Science.gov (United States)

    McLean, Siân A; Paxton, Susan J; Wertheim, Eleanor H

    2016-08-01

    Exposure to thin-ideal media can contribute to increased body dissatisfaction in adolescent girls. Understanding the factors that may prevent or exacerbate the negative effects of media exposure on body dissatisfaction is important to facilitate prevention of these problems. This study evaluated the effects of exposure to thin-ideal media images on body image in three instructional set experimental conditions: appearance comparison, peer norms, and control. An important aim was to examine baseline levels of media literacy as a protective factor and trait thin-ideal internalization and trait upward appearance comparison as risk factors. Early adolescent girls (N = 246) completed baseline measures and 1 week later viewed thin-ideal media images, before and after which they rated their state body satisfaction. Participants in the appearance comparison instruction but not peer norms instruction condition had significantly reduced body satisfaction. Media literacy, particularly high levels of critical thinking, mitigated the negative effects of trait thin-ideal internalization and trait upward appearance comparison on body satisfaction outcomes. These findings provide evidence for the role of media literacy as a protective factor against the negative effects on body satisfaction of exposure to thin-ideal media images, and also provide evidence to support the development and implementation of media literacy-based body image interventions.

  11. 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...

  12. Predicting, monitoring and controlling geomechanical effects of CO2 injection

    International Nuclear Information System (INIS)

    Streit, J.E.; Siggins, A.F.

    2005-01-01

    A key objective of geological carbon dioxide (CO 2 ) storage in porous rock is long-term subsurface containment of CO 2 . Fault stability and maximum sustainable pore-fluid pressures should be estimated in geomechanical studies in order to avoid damage to reservoir seals and fault seals of storage sites during CO 2 injection. Such analyses rely on predicting the evolution of effective stresses in rocks and faults during CO 2 injection. However, geomechanical analyses frequently do not incorporate poroelastic behaviour of reservoir rock, as relevant poroelastic properties are rarely known. The knowledge of rock poroelastic properties would allow the use of seismic methods for the accurate measurement of the effective stress evolution during CO 2 injection. This paper discussed key geomechanical effects of CO 2 injection into porous rock, and in particular, focused on the effects that the poroelasticity of reservoir rocks and pore pressure/stress coupling have on effective stresses. Relevant geophysical monitoring techniques were also suggested. The paper also outlined how these techniques could be applied to measure stress changes related to poroelastic rock behaviour during CO 2 injection and to test the predictions of sustainable changes in effective stress in CO 2 storage sites. It was concluded that a combination of predictive geomechanical techniques and application of geophysical monitoring techniques is a valid new concept for controlling and monitoring the geomechanical effects of CO 2 storage. 36 refs., 5 figs

  13. 1986 Index/Directory of Women's Media.

    Science.gov (United States)

    Allen, Martha Leslie, Ed.

    This is a directory of women's media, i.e., media primarily owned and operated by and for women. The mission of this annual publication is to aid networking among women, women's organizations, and women's media, both nationally and internationally. The directory includes two sections: women's media groups, and individual media women and…

  14. 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?

  15. INTERNATIONAL LEGAL FRAMEWORK FOR MEDIA

    Directory of Open Access Journals (Sweden)

    Nevenka Ronkova

    2016-04-01

    Full Text Available The analysis of the international legal framework for media in a real structural form is a challenge that needs to be scientifically proven because of the exceptional role of media in general and its constant and substantial impact on the democratic processes taking place in the world. If we analyze media through the eyes of history, we cannot ignore the impression of the exceptional importance of freedom of expression as the source and promoter of many substantive changes and valuable components in the overall functioning of social and political settings. In this regard, special attention is given to the impact of media on contemporary trends related to the EU integration process, the development of democracy and the rule of law. It particularly emphasizes the freedom of expression, respect for values and standards principles, human rights and freedoms. The purpose of this paper is to analyze the international legal framework for the media and to show the determination of the most important covenants which represent a source of media law containing rules for the creation and implementation of media freedom, the expressive quality of ideas and definitely and inevitably this paper stresses the power of the media.

  16. Organizational Media Affordances : Operationalization and Associations with Media Use

    OpenAIRE

    Rice, Ronald E.; Evans, Sandra K.; Pearce, Katy E.; Sivunen, Anu; Vitak, Jessica; Treem, Jeffrey W.

    2017-01-01

    The concept of affordances has been increasingly applied to the study of information and communication technologies (ICTs) in organizational contexts. However, almost no research operationalizes affordances, limiting comparisons and programmatic research. This article briefly reviews conceptualizations and possibilities of affordances in general and for media, then introduces the concept of organizational media affordances as organizational resources. Analysis of survey data from a large Nord...

  17. 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

  18. Change in tidal volume during cardiopulmonary resuscitation in newborn piglets.

    Science.gov (United States)

    Li, Elliott S; Cheung, Po-Yin; O'Reilly, Megan; Schmölzer, Georg M

    2015-11-01

    The purpose of inflations during cardiopulmonary resuscitation (CPR) is to deliver an adequate tidal volume (VT) to facilitate gas exchange. However, no study has examined VT delivery during chest compression (CC) in detail to understand the effect of CC on lung aeration. The aim of the study was to examine VT changes during CC and their effect on lung aeration. Piglets were anaesthetised, instrumented and intubated with zero leak. They were then randomly assigned to CPR using either 3:1 compression:ventilation ratio (C:V) (n=6), continuous CC with asynchronous ventilations (CCaV) (90 CC/min with 30/min asynchronous ventilations) (n=6) or continuous CC superimposed with 30 s sustained inflations (CC+SI) with a CC rate of 120/min (n=5). A respiratory function monitor (NM3, Respironics, Philips, Andover, Massachusetts, USA) was used to continuously measure inspiration tidal volume (VTi) and expirational tidal volume (VTe). ANOVA with Bonferroni post-test were used to compare variables of all three groups. During the inflation in the 3:1 C:V group, the mean (SD) VTi and VTe was 23.5 (5.3) mL/kg and 19.4 (2.7) mL/kg (p=0.16), respectively. During the CC, we observed a significant VT loss in the 3:1 group with VTi and VTe being 4.1 (1.2) mL/kg and 11.1 (3.3) mL/kg (p=0.007), respectively. In the CCaV group, VTe was higher compared with VTi, but this was not significant. In the CC+SI group, a VT gain during each CC with VTi and VTe of 16.3 (3.2) mL/kg and 14 (3) mL/kg (p=0.21), respectively, was observed. VT delivery is improved using CC+SI compared with 3:1 C:V. This improvement in VT delivery may lead to better alveolar oxygen delivery and lung aeration. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  19. Social Media and the Army

    Science.gov (United States)

    2010-04-01

    interaction and create dialogue at the click of a mouse. Social media has had an undeniable effect on the way we live, work, and communicate... benefits of social media applications, a bevy of opportunities present themselves when accurately strategized. Planning might include— Your Strategy...in establishing a positive social media presence. Trust enables leaders to open up their organizations to social media , and training provides

  20. Going Public on Social Media

    Directory of Open Access Journals (Sweden)

    Greg Elmer

    2015-04-01

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

  1. Inner Security in Media from the perspective of social science and media studies

    Directory of Open Access Journals (Sweden)

    Oliver Bidlo

    2012-07-01

    Full Text Available Security and entertainment are moving closer together. The term Securitainment expresses in this context, the mediation of security through entertainment formats. This will open a new space for Internal Security, which includes its own actors and patterns of interpretation. This space is portrayed in the media and follows the logic of media for attention but is also part of the process of social control. The mass media are therefore an instance of the design of internal security, social control and an interpretation producer. Mass media become actors of the internal security. They provide a symbolic representation of security.

  2. Social Media in Pediatric Orthopaedics.

    Science.gov (United States)

    Lander, Sarah T; Sanders, James O; Cook, Peter C; O'Malley, Natasha T

    Internet searches and social media utilization in health care has exploded over the past 5 years, and patients utilize it to gain information on their health conditions and physicians. Social media has the potential to serve as a means for education, communication, and marketing in all health care specialties. Physicians are sometimes reluctant to engage because of concerns of privacy, litigation, and lack of experience with this modality. Many surgical subspecialties have capitalized on social media but no study to date has examined the specific footprint of pediatric orthopaedic surgeons in this realm. We aim to quantify the utilization of individual social media platforms by pediatric orthopaedic surgeons, and identify any differences between private and hospital-based physicians, but also regional differences. Using the Pediatric Orthopaedic Society of North America Member Directory, each active member's social media presence was reviewed through an Internet search. Members were stratified on the basis of practice model and geographic location. Individual Internet searches, social media sites, and number of publications were reviewed for social media presence. Of 987 Pediatric Orthopaedic Society of North America members, 95% had a professional webpage, 14.8% a professional Facebook page, 2.2% a professional Twitter page, 36.8% a LinkedIn profile, 25.8% a ResearchGate profile, 33% at least 1 YouTube. Hospital-based physicians had a lower mean level of utilization of social media compared with their private practice peers, and a higher incidence of Pubmed publications. Private practice physicians had double the social media utilization. Regional differences reveal that practicing Pediatric Orthopaedists in the Northeast had increased utilization of ResearchGate and LinkedIn and the West had the lowest mean social media utilization levels. The rapid expansion of social media usage by patients and their family members is an undeniable force affecting the health

  3. 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...

  4. The Emerging Neuroscience of Social Media.

    Science.gov (United States)

    Meshi, Dar; Tamir, Diana I; Heekeren, Hauke R

    2015-12-01

    Social media use is a global phenomenon, with almost two billion people worldwide regularly using these websites. As Internet access around the world increases, so will the number of social media users. Neuroscientists can capitalize on the ubiquity of social media use to gain novel insights about social cognitive processes and the neural systems that support them. This review outlines social motives that drive people to use social media, proposes neural systems supporting social media use, and describes approaches neuroscientists can use to conduct research with social media. We close by noting important directions and ethical considerations of future research with social media. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. America’s Battle for Media Democracy: The Triumph of Corporate Libertarianism and the Future of Media Reform

    Directory of Open Access Journals (Sweden)

    Victor Pickard

    2014-11-01

    Full Text Available This contribution is a recording of the CAMRI research seminar held at the University of Westminster on November 19, 2014, in which Victor Pickard presented his book "America’s Battle for Media Democracy: The Triumph of Corporate Libertarianism and the Future of Media Reform": http://www.cambridge.org/gb/academic/subjects/politics-international-relations/american-government-politics-and-policy/americas-battle-media-democracy-triumph-corporate-libertarianism-and-future-media-reform Why do American media have so few public interest regulations? How did the American media system become dominated by a few corporations, and why are structural problems like market failures routinely avoided in media policy discourse? By tracing the answers to many of these questions back to media policy battles in the 1940s, Victor Pickard explains how this happened and why it matters today. Drawing from extensive archival research, the book uncovers the American media system’s historical roots and normative foundations. His book charts the rise and fall of a forgotten media reform movement to recover alternatives and paths not taken. As much about the present and future as it is about the past, the book proposes policies for remaking media based on democratic values for the digital age. Victor Pickard is an assistant professor at the Annenberg School for Communication at the University of Pennsylvania. Previously he taught media studies at NYU and the University of Virginia, and he worked on media policy in Washington, D.C. as a Senior Research Fellow at the media reform organization Free Press, the public policy think tank the New America Foundation, and Congresswoman Diane Watson’s office. He has published numerous journal articles and book chapters on the history and political economy of media institutions and media reform activism. His op-eds on media policy debates and the future of journalism have appeared in news outlets like The Guardian, The Seattle

  6. Media Use by Children, and Parents' Views on Children's Media Usage.

    Science.gov (United States)

    Dinleyici, Meltem; Carman, Kursat Bora; Ozturk, Emel; Sahin-Dagli, Figen

    2016-06-07

    New (mobile phones, smartphones, tablets, and social media) and traditional media (television) have come to dominate the lives of many children and adolescents. Despite all of this media time and new technology, many parents seem to have few rules regarding the use of media by their children and adolescents. The aim of this study was to evaluate media access/use of children and to evaluate beliefs and attitudes of parents concerning the use of old and new media in Turkey. This is a cross-sectional electronic survey of a national convenience sample in Turkey via SurveyMonkey, including 41 questions regarding topics relevant to television, computers, mobile phones, iPad/tablet use, and social media accounts. The responses of the 333 participants (238 women, 95 men; 27-63 years) were evaluated. The average daily watching alone time was 0 to 2 hours among 53.4% (46/86), and daily coviewing time with parents of children was 0 to 2 hours among 62.7% (54/86) of children below 2 years of age. Regarding parents' monitoring their children's computer use (n=178), 35.4% (63/178) of the parents prefer coviewing, 13.5% of the parents use a family filter (24/178), and 33.1% (59/178) of the parents prefer to check Web history. Approximately 71.2% (237/333) of the participants had an iPad/tablet in the house, 84.3% (200/333) of the parents give their children permission to use the iPad/tablet. Of the parents, 22.5% (45/200) noted that their children used the iPad/tablet at the table during lunch/dinner and 57.9% (26/45) of these children were aged 5 years and below. Of parents, 27.3% (91/333) agreed that the optimal age for owning a mobile phone was 12 years, and 18.0% (60/333) of the parents noted that their children (one-third was below 2 years) used the mobile phone at the table during meals. A total of 33.3% (111/333) children/adolescents have a Facebook profile, and 54.0% (60/111) were below 13 years of age. Approximately 89.2% (297/333) of the parents emphasized that the

  7. Journalism and Media Crossing Field Boundaries

    DEFF Research Database (Denmark)

    Svith, Flemming

    Journalism and media have been fitted together for decades fulfilling each other needs. However, due to some main drivers as new communication technology and the societal medialization process media and journalism have changed dramatically and in the case of Denmark this symbiosis is broken....... This article explores such changes in Denmark by using key concepts of the French sociologist Pierre Bourdieu in a historical study of media and journalism in the last four decades. Based on data of journalist functions in society and the emergence and distribution of new types of media, combined...... with the positioning of media and journalists and the existing knowledge in the media and journalism literature, this paper analyze media and journalism as two distinct analytic objects representing respectively media organization and the journalist profession. Firstly, this paper thus constructs synchronic...

  8. Media education as a system of health personalities software in media-information space

    Directory of Open Access Journals (Sweden)

    Ye. M. Velykodna

    2014-04-01

    Full Text Available The main purpose of the article is to outline the problems of health and human security in the media­information education space. Media education as a system of values formation under conditions of medial ­ information educational environment focused on developing and providing protective functions in their close interdependence. Training is aimed at creating conditions for the development of spiritual subjects of education, promotion of positive changes in their personal development. Protective aimed at improving the social protection of business education in the destructive tendencies in society , to neutralize the impact of negative factors media. The most important part of media education in the context of ensuring the health of the individual is the formation of values education activity as the basis of spiritual health. It is shown that meaningful use sens formative influence of media­information space determines the priority position of media education as a factor in providing mental health of the individual. Formation of mental health is associated with the conscious assimilation of certain belief systems of the world. According media education focuses not on broadcast ready «moral absolutes «, and the simulation of specific situations in which the individual is necessary to self­determination regarding fundamental values and principles of implementing these values in life.

  9. Pulmonary tissue volume, cardiac output, and diffusing capacity in sustained microgravity

    Science.gov (United States)

    Verbanck, S.; Larsson, H.; Linnarsson, D.; Prisk, G. K.; West, J. B.; Paiva, M.

    1997-01-01

    In microgravity (microG) humans have marked changes in body fluids, with a combination of an overall fluid loss and a redistribution of fluids in the cranial direction. We investigated whether interstitial pulmonary edema develops as a result of a headward fluid shift or whether pulmonary tissue fluid volume is reduced as a result of the overall loss of body fluid. We measured pulmonary tissue volume (Vti), capillary blood flow, and diffusing capacity in four subjects before, during, and after 10 days of exposure to microG during spaceflight. Measurements were made by rebreathing a gas mixture containing small amounts of acetylene, carbon monoxide, and argon. Measurements made early in flight in two subjects showed no change in Vti despite large increases in stroke volume (40%) and diffusing capacity (13%) consistent with increased pulmonary capillary blood volume. Late in-flight measurements in four subjects showed a 25% reduction in Vti compared with preflight controls (P volume, to the extent that it was no longer significantly different from preflight control. Diffusing capacity remained elevated (11%; P pulmonary perfusion and pulmonary capillary blood volume, interstitial pulmonary edema does not result from exposure to microG.

  10. PoliMedia. Analysing Media Coverage of political debates by automatically generated links to Radio & Newspaper Items

    NARCIS (Netherlands)

    M. Kleppe (Martijn); L. Hollink (Laura); M.J. Kemman (Max); D. Juric (Damir); H.J.G. Beunders (Henri); J. Blom (Jaap); J. Oomen (Johan); G.J. Houben (Geert Jan)

    2014-01-01

    markdownabstractStudents and researchers of media and communication sciences study the role of media in our society. They frequently search through media archives to manually select items that cover a certain event. When this is done for large time spans and across media-outlets, this task can

  11. A Case Study On Media Literacy Levels Of Secondary Students Who Attend Media Literacy Course

    Directory of Open Access Journals (Sweden)

    Erhan GÖRMEZ

    2017-05-01

    Full Text Available The aim of this study is to determine the media literacy levels of secondary school students who attend media literacy courses. In this qualitative study, interview method was used to gather required data. In this qualitative study, interview method was used to gather required data. The interviews were conducted with 10 secondary school students of grade 8 attending media literacy courses by using semi-structured interview forms developed by the researcher. The questions used in semi-structured interview forms were prepared considering the outcomes of Media Literacy program related to units in Media Literacy Lesson Teacher Guide Book such as What is Communication?, Mass Communication, Media, Television, Newspaper and the Internet. The data gathered through the student's interviews were analyzed by applying content analysis method. Having evaluated the research results, it was concluded that the students who attend Media Literacy courses have a bit data and skills as knowing what communication is, using media and knowing its functions, telling the difference between TV program sorts in terms of their functions, knowing smart signs and explanations and obeying them, knowing basic concepts about newspaper and knowing and applying basic concepts concerning internet usage.

  12. Media advocacy: lessons from community experiences.

    Science.gov (United States)

    Jernigan, D H; Wright, P A

    1996-01-01

    Media advocacy is the strategic use of mass media and community organizing as a resource for advancing a social or public policy initiative. Across the United States, communities are using media advocacy to promote healthier public policies and environments. The U.S. Center for Substance Abuse Prevention commissioned numerous case studies of media advocacy on alcohol and tobacco issues in a diverse array of communities, including efforts in African-American and Latino communities or using computer-based electronic communication systems. The paper describes these efforts briefly, and summarizes lessons learned, including: media advocacy can lead to larger victories when used as a complement to community organizing in the context of a larger strategic vision for policy change; like policy advocacy, media advocacy is best done in the context of clear long-term goals; conscious framing, guiding the choice of spokespeople, visuals, and messages, can alter media coverage and public debate of health policies; advocates need to respect the media but also remember that they have power in relation to the media; and media advocacy is often controversial and not suited to every situation. The case studies show that media advocacy is a potent tool for public health workers, making an important contribution to campaigns to promote healthier public policies.

  13. Harnessing the Power of Media Relations and Social Media and Public Outreach

    OpenAIRE

    Farmer, Andrea; Pinkerton, Jim; Pipkin, Erin; Riggs, Nathan

    2013-01-01

    This presentation discusses strategies for launching a simple, yet effective, campaign through media relations and social media for public outreach. Key points regarding protocol and time management will be covered.

  14. Multi-criteria media mix decision model for advertising multiple product with segment specific and mass media

    Directory of Open Access Journals (Sweden)

    Sugandha Aggarwal

    2014-12-01

    Full Text Available Judicious media planning decisions are crucial for successful advertising of products. Media planners extensively use mathematical models supplemented with market research and expert opinion to devise the media plans. Media planning models discussed in the literature largely focus on single products with limited studies related to the multi-product media planning. In this paper we propose a media planning model to allocate limited advertising budget among multiple products advertised in a segmented market and determine the number of advertisements to be given in different media. The proposed model is formulated considering both segment specific and mass media vehicles to maximize the total advertising reach for each product. The model also incorporates the cross product effect of advertising of one product on the other. The proposed formulation is a multi-objective linear integer programming model and interactive linear integer goal programming is discussed to solve the model. A real life case study is presented to illustrate the application of the proposed model.

  15. Social media and disasters: a functional framework for social media use in disaster planning, response, and research.

    Science.gov (United States)

    Houston, J Brian; Hawthorne, Joshua; Perreault, Mildred F; Park, Eun Hae; Goldstein Hode, Marlo; Halliwell, Michael R; Turner McGowen, Sarah E; Davis, Rachel; Vaid, Shivani; McElderry, Jonathan A; Griffith, Stanford A

    2015-01-01

    A comprehensive review of online, official, and scientific literature was carried out in 2012-13 to develop a framework of disaster social media. This framework can be used to facilitate the creation of disaster social media tools, the formulation of disaster social media implementation processes, and the scientific study of disaster social media effects. Disaster social media users in the framework include communities, government, individuals, organisations, and media outlets. Fifteen distinct disaster social media uses were identified, ranging from preparing and receiving disaster preparedness information and warnings and signalling and detecting disasters prior to an event to (re)connecting community members following a disaster. The framework illustrates that a variety of entities may utilise and produce disaster social media content. Consequently, disaster social media use can be conceptualised as occurring at a number of levels, even within the same disaster. Suggestions are provided on how the proposed framework can inform future disaster social media development and research. © 2014 2014 The Author(s). Disasters © Overseas Development Institute, 2014.

  16. Media Education: Opinions of Russian Teachers

    Directory of Open Access Journals (Sweden)

    Alexander Fedorov

    2014-11-01

    Full Text Available The analysis of the conducted questionnaire among teachers of secondary schools showed that realizing the great importance of the media in the contemporary information society, three quarters of them support the idea of media education at schools and 58% believe that a new major for pedagogical institutes needs to be introduced - “Media Education”. Most of teachers justly think that the combination of the autonomous and integrated media lessons is the most effective way today for the development of media education in Russia, and therefore - for the increase of media literacy of the young generation. However, in spite of the fact that majority of teachers define the aim to develop the critical thinking of the audience as one of the most important, they significantly overestimate the weight of “protectionist” approach to media studies today, and on the contrary, undervalue the goals to develop the democratic thinking of the pupils, their knowledge about theory and history of media and media culture. Moreover, despite of the general support of media education ideas (in theory expressed by 75 % of the teachers, actually only one third of them use some elements of media education at their lessons (in reality, and one fifth of the group does not integrate it at all. The hardest obstacle on the way of media education into the Russian classrooms is the absence of financial motivation, according to the teachers, though to our point of view, last but not the least is the passive anticipation of the authority’s directives and insufficient level of knowledge of today’s Russian teachers in terms of the theory and methods of media education. Thus, the analysis of the teachers’ questionnaire has given us additional proof for the necessity of the official introduction of the new university-level Major- “Media Education” (namely, Major, because the homonymous Minor was registered in 2002 and media education courses for the students of all

  17. The Effects of Frequency of Media Utilization on Decision Making of Media Choice

    Science.gov (United States)

    Gotoh, Yasushi

    2014-01-01

    The purpose of this study is to use the Analytic Hierarchy Process in order to identify how frequency of media use in daily life affects decision-making in media choice. 276 university students took part in this research, They were asked to prioritize their ways of obtaining information about current affairs using sets of media such as TV, books,…

  18. Orchestrating the Media Collage

    Science.gov (United States)

    Ohler, Jason

    2009-01-01

    Modern literacy has always meant being able to both read and write narrative in the media forms of the day, whatever they may be. Just being able to read is not sufficient. A new dimension of literacy is now in play--namely, the ability to adapt to new media forms and fit them into the overall media collage quickly and effectively. A strong case…

  19. The Paradox of Liveness. From the Broadcast Media Era to the Social Media Era

    NARCIS (Netherlands)

    van Es, K.F.

    2014-01-01

    Liveness has been a persistent and much-debated concept in media studies. It has long been associated with broadcast media, and television in particular. However, the emergence of social media, following the dot-com bubble bust, has brought new forms of liveness into effect. These challenge common

  20. Competition and Commercial Media Bias

    OpenAIRE

    Blasco, Andrea; Sobbrio, Francesco

    2011-01-01

    This paper reviews the empirical evidence on commercial media bias (i.e., advertisers influence over media accuracy) and then introduces a simple model to summarize the main elements of the theoretical literature. The analysis provides three main policy insights for media regulators: i) Media regulators should target their monitoring efforts towards news contents upon which advertisers are likely to share similar preferences; ii) In advertising industries characterized by high correlation in ...