Variations in mid-ocean ridge CO2 emissions driven by glacial cycles

The geological record shows links between glacial cycles and volcanic productivity, both subaerially and at mid-ocean ridges. Sea-level-driven pressure changes could also affect chemical properties of mid-ocean ridge volcanism. We consider how changing sea-level could alter the CO2 emissions rate from mid-ocean ridges, on both the segment and global scale. We develop a simplified transport model for a highly incompatible element through a homogenous mantle; variations in the melt concentration the emission rate of the element are created by changes in the depth of first silicate melting. The model predicts an average global mid-ocean ridge CO2 emissions-rate of 53 Mt/yr, in line with other estimates. We show that falling sea level would cause an increase in ridge CO2 emissions with a lag of about 100 kyrs after the causative sea level change. The lag and amplitude of the response are sensitive to mantle permeability and plate spreading rate. For a reconstructed sea-level time series of the past million years, we predict variations of up to 12% (7 Mt/yr) in global mid-ocean ridge CO2 emissions. The magnitude and timing of the predicted variations in CO2 emissions suggests a potential role for ridge carbon emissions in glacial cycles

Power cepstrum technique with application to model helicopter acoustic data

The application of the power cepstrum to measured helicopter-rotor acoustic data is investigated. A previously applied correction to the reconstructed spectrum is shown to be incorrect. For an exact echoed signal, the amplitude of the cepstrum echo spike at the delay time is linearly related to the echo relative amplitude in the time domain. If the measured spectrum is not entirely from the source signal, the cepstrum will not yield the desired echo characteristics and a cepstral aliasing may occur because of the effective sample rate in the frequency domain. The spectral analysis bandwidth must be less than one-half the echo ripple frequency or cepstral aliasing can occur. The power cepstrum editing technique is a useful tool for removing some of the contamination because of acoustic reflections from measured rotor acoustic spectra. The cepstrum editing yields an improved estimate of the free field spectrum, but the correction process is limited by the lack of accurate knowledge of the echo transfer function. An alternate procedure, which does not require cepstral editing, is proposed which allows the complete correction of a contaminated spectrum through use of both the transfer function and delay time of the echo process

Dislocating the Eschaton? Appraising Realized Eschatology

Was Jesus Christ a deluded prophet who expected an imminent collapse of the world followed by the dawning of a kingdom that has never eventuated? Some who reject Christianity think that he was, and as a consequence are highly suspicious about any other claims that are attributed to Jesus. But other interpretations of the apparently eschatological pronouncements in the New Testament exist, one of which is realized eschatology, this being the idea, roughly, that the kingdom or reign of God was realized in or through the ministry of Jesus itself. Debates surrounding the competing interpretations of New Testament eschatology raise fascinating issues, both exegetical and conceptual. Exploring some of these issues from the perspective of philosophy of religion, informed by theological and biblical studies, this article argues that realized eschatology is a religious option that, contrary to common criticisms, is neither incoherent nor implausibly reductive

Karma and Rebirth in the stream of thought and life

This essay explores the concepts of karma and rebirth in the light of some key themes from the later work of Wittgenstein. After clarifying what it means to “bring words back from their metaphysical to their everyday use” it is considered how certain Wittgenstein-influenced philosophers, notably İlham Dilman and D. Z. Phillips, have sought to recover the meaning of “soul” from metaphysical misappropriations by invoking Wittgenstein’s notion of a “picture” The sort of conceptual recovery involved in this task resembles, in some respects, the “demythologizing” and “psychologizing” approaches of certain interpreters of the doctrine of karma and rebirth, especially within the context of Buddhist studies. Illustrative examples of these approaches are compared and contrasted and discussed in relation to instances of individuals articulating their belief in karma and rebirth. On the basis of this discussion, it is concluded that the interpretive approaches in question fail to account for the sense of individual responsibility for one’s own present circumstances that is central to how talk of karma and rebirth frequently operates “in the stream of thought and life.

D. Z. Phillips' Contemplations on Religion and Literature

This paper critically discusses D. Z. Phillips’ use of literary works as a resource for philosophical reflection on religion. Beginning by noting Phillips’ suggestion, made in relation to Waiting for Godot, that the possibilities of meaning that we see in a literary work can reveal something of our own religious sensibility, I then proceed to show what we learn about Phillips from his readings of certain works by Larkin, Tennyson, and Wharton. Through exploring alternative possible readings, I argue that, although Phillips’ discussions are of considerable philosophical interest, they undermine his claim to be deploying a purely contemplative hermeneutical method

Thickening description: Towards an expanded conception of philosophy of religion

An increasingly common complaint about philosophy of religion — especially, though not exclusively, as it is pursued in the “analytic tradition” — is that its preoccupation with questions of rationality and justification in relation to “theism” has deflected attention from the diversity of forms that religious life takes. Among measures proposed for ameliorating this condition has been the deployment of “thick description” that facilitates more richly contextualized understandings of religious phenomena. Endorsing and elaborating this proposal, I provide an overview of different but related notions of thick description before turning to two specific examples, which illustrate the potential for engagement with ethnography to contribute to an expanded conception of philosophy of religion

Static investigation of two STOL nozzle concepts with pitch thrust-vectoring capability

A static investigation of the internal performance of two short take-off and landing (STOL) nozzle concepts with pitch thrust-vectoring capability has been conducted. An axisymmetric nozzle concept and a nonaxisymmetric nozzle concept were tested at dry and afterburning power settings. The axisymmetric concept consisted of a circular approach duct with a convergent-divergent nozzle. Pitch thrust vectoring was accomplished by vectoring the approach duct without changing the nozzle geometry. The nonaxisymmetric concept consisted of a two dimensional convergent-divergent nozzle. Pitch thrust vectoring was implemented by blocking the nozzle exit and deflecting a door in the lower nozzle flap. The test nozzle pressure ratio was varied up to 10.0, depending on model geometry. Results indicate that both pitch vectoring concepts produced resultant pitch vector angles which were nearly equal to the geometric pitch deflection angles. The axisymmetric nozzle concept had only small thrust losses at the largest pitch deflection angle of 70 deg., but the two-dimensional convergent-divergent nozzle concept had large performance losses at both of the two pitch deflection angles tested, 60 deg. and 70 deg