1,107 research outputs found

    Scale on Wire Rod and its Removal by Mechanical Means

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    The rod from Which plain carbon steel wire is produced is normally supplied in the original rolled condition with its scale attached. As a preliminary to the succ-essful drawing of the rod down to wire, it is essential to remove this scale. The traditional method of removal has been to pickle the rod coils by submerging them in solutions of dilute acid. In recent years one has seen developments introduced to achieve mechanical scale removal

    On the Origin of Radial Anisotropy Near Subducted Slabs in the Midmantle

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    Recent seismic studies indicate the presence of seismic anisotropy near subducted slabs in the transition zone and uppermost lower mantle (mid-mantle). In this study, we investigate the origin of radial anisotropy in the mid-mantle using 3-D geodynamic subduction models combined with mantle fabric simulations. These calculations are compared with seismic tomography images to constrain the range of possible causes of the observed anisotropy. We consider three subduction scenarios: (i) slab stagnation at the bottom of the transition zone; (ii) slab trapped in the uppermost lower mantle; and (iii) slab penetration into the deep lower mantle. For each scenario, we consider a range of parameters, including several slip systems of bridgmanite and its grain-boundary mobility. Modeling of lattice-preferred orientation shows that the upper transition zone is characterized by fast-SV radial anisotropy anomalies up to 121.5%. For the stagnating and trapped slab scenarios, the uppermost lower mantle is characterized by two fast-SH radial anisotropy anomalies of 3c+2% beneath the slab's tip and hinge. On the other hand, the penetrating slab is associated with fast-SH radial anisotropy anomalies of up to 3c+1.3% down to a depth of 2,000\ua0km. Four possible easy slip systems of bridgmanite lead to a good consistency between the mantle modeling and the seismic tomography images: [100](010), [010](100), [001](100), and (Formula presented.). The anisotropy anomalies obtained from shape-preferred orientation calculations do not fit seismic tomography images in the mid-mantle as well as lattice-preferred orientation calculations, especially for slabs penetrating into the deep lower mantle

    Ubiquitous lower-mantle anisotropy beneath subduction zones

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    Seismic anisotropy provides key information to map the trajectories of mantle flow and understand the evolution of our planet. While the presence of anisotropy in the uppermost mantle is well established, the existence and nature of anisotropy in the transition zone and uppermost lower mantle are still debated. Here we use three-dimensional global seismic tomography images based on a large dataset that is sensitive to this region to show the ubiquitous presence of anisotropy in the lower mantle beneath subduction zones. Whereas above the 660 km seismic discontinuity slabs are associated with fast SV anomalies up to about 3%, in the lower mantle fast SH anomalies of about 2% persist near slabs down to about 1,000–1,200 km. These observations are consistent with 3D numerical models of deformation from subducting slabs and the associated lattice-preferred orientation of bridgmanite produced in the dislocation creep regime in areas subjected to high stresses. This study provides evidence that dislocation creep may be active in the Earth’s lower mantle, providing new constraints on the debated nature of deformation in this key, but inaccessible, component of the deep Earth

    The Relationship Between Belief and Credence

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    Sometimes epistemologists theorize about belief, a tripartite attitude on which one can believe, withhold belief, or disbelieve a proposition. In other cases, epistemologists theorize about credence, a fine-grained attitude that represents one’s subjective probability or confidence level toward a proposition. How do these two attitudes relate to each other? This article explores the relationship between belief and credence in two categories: descriptive and normative. It then explains the broader significance of the belief-credence connection and concludes with general lessons from the debate thus far

    Science's immunity to moral refutation

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    Our moral convictions cannot, on the face of it, count in evidence against scientific claims with which they happen to conflict. Moral anti-realists of whatever stripe can explain this easily: science is immune to moral refutation because moral discourse is defective as a trustworthy source of true and objective judgments. Moral realists, they can add, are unable to explain this immunity. After describing how anti-realists might implement this reasoning, the paper argues that the only plausible realist comeback turns on the practical nature of moral reasoning. This comeback, however, places significant constraints on the structure of evidence for moral judgments. These constraints cannot be met by coherentist defenders of reflective-equilibrium methodology or by anyone sympathetic to bottom-up, case-driven foundationalism, including those who claim we have perceptual or perception-like access to moral truths. Unfortunately for realists in these categories, alternative realism-friendly accounts of science’s apparent moral immunity are unpromising. These neither explain nor explain away our unwillingness to infer an is from an ought, as Hume might have put it. Science’s apparent immunity to moral refutation therefore poses a serious problem for any realist unhappy with top-down, theory-driven conceptions of the structure of moral evidence

    Can Modal Skepticism Defeat Humean Skepticism?

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    My topic is moderate modal skepticism in the spirit of Peter van Inwagen. Here understood, this is a conservative version of modal empiricism that severely limits the extent to which an ordinary agent can reasonably believe “exotic” possibility claims. I offer a novel argument in support of this brand of skepticism: modal skepticism grounds an attractive (and novel) reply to Humean skepticism. Thus, I propose that modal skepticism be accepted on the basis of its theoretical utility as a tool for dissolving philosophical paradox

    Alpha-fetoprotein detection of hepatocellular carcinoma leads to a standardized analysis of dynamic AFP to improve screening based detection

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    Detection of hepatocellular carcinoma (HCC) through screening can improve outcomes. However, HCC surveillance remains costly, cumbersome and suboptimal. We tested whether and how serum Alpha-Fetoprotein (AFP) should be used in HCC surveillance. Record linkage, dedicated pathways for management and AFP data-storage identified i) consecutive highly characterised cases of HCC diagnosed in 2009-14 and ii) a cohort of ongoing HCC-free patients undergoing regular HCC surveillance from 2009. These two well-defined Scottish patient cohorts enabled us to test the utility of AFP surveillance. Of 04 cases of HCC diagnosed over 6 years, 42% (129) were identified by a dedicated HCC surveillance programme. Of these 129, 47% (61) had a detectable lesion first identified by screening ultrasound (US) but 38% (49) were prompted by elevated AFP. Despite pre-HCC diagnosis AFP >20kU/L being associated with poor outcome, 'AFP-detected' tumours were offered potentially curative management as frequently as 'US-detected' HCCs; and had comparable survival. Linearity of serial log10 -transformed AFPs in HCC cases and in the screening 'HCC-free' cohort (n = 1509) provided indicators of high-risk AFP behaviour in HCC cases. An algorithm was devised in static mode, then tested dynamically. A case/control series in hepatitis C related disease demonstrated highly significant detection (p-5) of patients at high risk of developing HCC. These data support the use of AFP in HCC surveillance. We show proof-of-principle that an automated and further refineable algorithmic interpretation of AFP can identify patients at higher risk of HCC. This approach could provide a cost-effective, user-friendly and much needed addition to US surveillance
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