88,295 research outputs found
Fracture Mechanics Characterization of an AnisotropicGeomaterial
No full textArgillites are considered worldwide as potential host rock for high level radioactive waste given the low permeability and strong adsorption potential. However, the excavation of the galleries of a repository would produce a disturbed zone around the boundaries rich of new fractures which may enhance the conductivity of the rock along the gallery axis. Several mine-by experiments have been performed in underground rock labs to investi- gate the features of the disturbed zone. In Mont Terri URL (Kanton Jura, Switzerland) the EZ-B experiment was specifically conceived for the measurement of excavation induced fractures around a small chamber. The host rock of the URL is a particularly compact and resistant argillite, known as the Opalinus Clay (OPA) excavated and OPA samples were subjected to fracture mechanics tests at the rock mechanics lab of IGAG-CNR in Torino, Italy. The tests aimed at the understanding aspects of the fracturing process occurring in OPA of Mont Terri, which may be considered a transversely isotropic geomaterial, whose planes of isotropy coincide with the beddin
Hydrodynamic controls on the particle size of resuspended sediment from sandy and muddy substrates in British Columbia, Canada
No full textA benthic annular flume, Sea Carousel, was deployed at both sand-dominated (Baynes Sound) and mud-dominated (Carrie Bay) stations in British Columbia, Canada, to examine the character of near-bed flow over these contrasting bottom types and its control on particle size of resuspended sediment. An assessment has also been made of the turbidity-induced drag reduction due to suspension of bottom sediments. The median sizes of suspended material from the sandy sites have been compared with the well-known Rouse theory, whereas the aggregates resuspended from muddy stations were scaled with the energy dissipation rate (ϵ) determined from high-frequency three-dimensional flow measures in the flume. There was no evidence in the turbulence spectra in the Sea Carousel of energy inputs in the paddle and lid rotational frequencies, and a f-5/3 slope for f > 2 Hz in turbulent transitional flows was evident. The bed roughness length of sandy sites was Reynolds-number dependent but was asymptotic to a constant value of 2 mm at high flows. This equated to a dimensionless drag coefficient at 1 m above bed of a constant, 3 × 10-3 (also at high Reynolds numbers), which agrees well with values reported in the literature. The median size of suspended sand (from the sandy sites) and equivalent still water settling rate (ws) scaled with the friction velocity (u*) in the form ws/u* = D*/8. The median size of resuspended aggregates (df) scaled inversely with dissipation (ϵ) in the form df = 5 × 10-6ϵ-0.24m, which is close to the relationship found in the literature.</p
Biogeochemical processes in a clay formation in situ experiment: Part E – Equilibrium controls on chemistry of pore water from the Opalinus Clay, Mont Terri Underground Research Laboratory, Switzerland
No full textInternational audienceThe chemistry of pore water (particularly pH and ionic strength) is an important property of clay rocks being considered as host rocks for long-term storage of radioactive waste. Pore waters in clay-rich rocks generally cannot be sampled directly. Instead, their chemistry must be found using laboratory-measured properties of core samples and geochemical modelling. Many such measurements have been made on samples from the Opalinus Clay from the Mont Terri URL. Several boreholes in that URL yielded water samples against which pore water models have been calibrated. Following a first synthesis report published in 2003 (Pearson, F. J., et al.., 2003. Mont Terri project - Geochemistry of water in the Opalinus clay formation at the Mont Terri Rock Laboratory. Geology Series No. 5 Swiss Federal Office for Water and Geology, Bern.), this paper presents the evolution of the modelling approaches developed within Mont-Terri URL scientific programs through the last decade (1997-2009). Models are compared to the composition of waters sampled during dedicated borehole experiments. Reanalysis of the models, parameters and database enabled the principal shortcomings of the previous modelling efforts to be overcome. The inability to model the potassium concentrations correctly with the measured cation exchange properties was found to be due to the use of an inappropriate selectivity coefficient for Na-K exchange; the inability to reproduce the measured carbonate chemistry and pH of the pore waters using mineral-water reactions alone was corrected by considering clay mineral equilibria as done by Gaucher et al. (Gaucher, E. C., Tournassat, C., Pearson, F. J., Blanc, P., Crouzet, C., Lerouge, C., and Altmann, S., 2009. A robust model for clayrock porewater chemistry. Geochimica & Cosmochimica Acta 73, 6470-6483). Re-examination of the measured calcium/magnesium activity ratios and consideration of the mineralogical composition of the Opalinus Clay suggested that calcium/magnesium cation exchange rather than dolomite saturation may control the ratio of these ions in solution. This re-examination also suggests that the calcium/magnesium ratio decreases with increasing pore water salinity. Several possible reasons for this are proposed. Moreover, it is demonstrated that feldspar equilibria must not be included in Opalinus Clay modelling because feldspars are present only in very small quantities in the formation and because sodium/potassium ratios measured in pore water samples are inconsistent with feldspar saturation. The principal need to improve future modelling is additional or better data on rock properties, in particular: (i) a more detailed identification of phases in the Opalinus Clay that include redox-sensitive elements together with evaluation of their thermodynamic properties; (ii) an improved understanding of the distribution of celestite throughout the Opalinus Clay for Sr/sulphate concentrations control; (iii) improvements in analytic and thermodynamic data for Ca-Mg rock cation exchange and mineral chemical properties and (iv) the measurement of composition and stability constants of clay minerals actually present in the formation
Performance Anxiety: An exploration of spectacle, spectatorship and moral panic in the twenty-first century
No full textIn the last decade there has been an explosion of new technologies that enable discourse, power and truth formations to be produced, contested and dispersed. As communication and information technologies continue to evolve, so too do the ways in which individuals construct identities and form communities. The notion of a moral panic is utilised to describe those critical moments in time and space when social norms are perceived to be under threat. I suggest that the complex interplay of spectacle, spectatorship and moral panic involved in such instances can be both conceptualised and interrogated as performance. This dissertation draws upon two distinct performance paradigms – one theoretical and the other practical – to inform a critical reading of three significant ‘social events’ of the last decade: the drug-trafficking trial of Australian woman Schapelle Corby in Indonesia in 2005, the end-of-life legal case focused on American woman Terri Schiavo, which culminated in 2005, and the race relations associated with the ‘Redfern riots’ which occurred in Sydney in 2004. Informed by a range of theoretical positions from Michel Foucault, Zygmunt Bauman, Giorgio Agamben, Judith Butler, Baz Kershaw, and Michael Hardt and Antonio Negri, this dissertation fleshes out contemporary understandings of mediatised spectacle and spectatorship, with the aim of revealing the ways in which they contribute to creating and sustaining moral panic. A critical finding of the dissertation is that through both subjectification and objectification processes the central players and the spectators become indivisible from the spectacle itself, thus maintaining the interweaving cycle of spectator, spectacle and moral panic. By exploring the ways in which people interpret and respond to social phenomena, the possibilities for performance and social theory can be extended
Identity and Immigrant Stereotypes: A Study Based on the Ego-Ecological Approach
No full textBased on the ego-ecological approach, which views identity as deeply interconnected with the social environment via group memberships, this study reconstructed the psychosocial identity of a group of Sri Lankan immigrants who settled in Naples, Italy, with the aim of detecting resonances between their self-representations and the stereotypes circulating in the receiving society. Fifty-one Sri Lankan immigrants completed a shortened version of the Multistage Investigator of Social Identity (MISI) with the following two stimulus groups: “Sri Lankans” (i.e., ethnocultural identity) and “immigrants.” Analyses revealed an implication of the self in both groups (i.e., Sri Lankans and immigrants), with the represented immigrant self more negatively connoted than the ethnocultural self. The contents of the self-representations showed resonances with both the stereotypes associated with immigrants in Italian society and the specific stereotype associated with the Sri Lankan community, thereby empirically confirming that in the immigrant experience identity feels the effect of the attitudes of the receiving context
An in situ assessment of seabed stability in Baynes Sound, British Columbia, Canada
No full textSutherland, T.F. and Amos, C.L., 2020. An in situ assessment of seabed stability in Baynes Sound, British Columbia, Canada. Journal of Coastal Research, 36(3), 472-486. Coconut Creek (Florida), ISSN 0749-0208. The Sea Carousel, an annular flume, was deployed to examine (in situ) fundamental parameters of seabed stability in Baynes Sound, British Columbia, Canada. Sediment grain size, water and organic contents, and chlorophyll and phaeopigment concentrations were collected to establish a hierarchy of factors associated with seabed stability. Sediment stability increased toward the Sound entrance in concert with decreases in water, organic, and silt-clay contents and a transition from cohesive to noncohesive properties. Bed-stress estimates, based on the quadratic stress law and turbulent kinetic energy (TKE) methods, showed a decrease in the drag coefficient from the inner (0.04) to the outer (0.0015) Sound. Surface erosion thresholds ranged between 0.04 to 0.28 Pa, whereas the friction coefficients (e.g., the failure envelop) were on average 12°, representing normally consolidated sediments. Type I (floc) erosion occurred at low shear stresses, whereas type II (mass) erosion happened at higher values. Erosion rates (E, for type I erosion) fitted a power function of excess shear stress (E
m = τ0 - τcrit,z)m with zero offset, where 0.81 < m < 2.32. The lowest and highest values for a given excess-shear stress occurred in the inner Sound and outer Sound, respectively. Settling of (resuspended) sediment after an exponential decay law [d(SSC)/dt] = SSC0 (expkt), where k fell within that of published values (3 < k < 539). Higher values of k (fastest settling) were observed in the inner Sound relative to the outer Sound. The sedimentation diameter (ds) fell in a coarse-silt to fine-sand range and was larger in the outer Sound, reflecting a coarsening of bed sediments.
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Apolipoprotein A-IV synthesis in rat intestine: regulation by dietary triglyceride
No full text Page G662: Terri F. Apfelbaum, Nicholas O. Davidson, and Robert M. Glickman. “Apolipoprotein A-IV synthesis in rat intestine: regulation by dietary triglyceride.” Page G663: sentence beginning on line 10, second column, should read “Data are expressed as mean ± 1 SD, and comparisons for both paired and unpaired means were made by Students t test.” </jats:p
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
[Newspaper Clipping: Author Claims Evidence of Second JFK Assassin #1]
No full textNewspaper article titled "Author Claims Evidence of Second JFK Assassin." The article states that author Richard J. Whalen concluded "that there is circumstantial evidence to support the theory of a second assassin in the shooting of President John F. Kennedy.
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