In this Issue Content Type Journal Article Pages 7-9 Authors Jason M. Wirth Michael Schwartz Journal Comparative and Continental Philosophy Online ISSN 1757-0646 Print ISSN 1757-0638 Journal Volume Volume 4 Journal Issue Volume 4, Number 1 / 2012.
An in-situ transmission electron microscopy straining technique has been used to investigate the dynamics of dislocation-defect interactions in ion-irradiated copper and the subsequent formation of defect-free channels. Defect removal frequently required interaction with multiple dislocations, although screw dislocations were more efficient at annihilating defects than edge dislocations were. The defect pinning strength was determined from the dislocation curvature prior to breakaway and exhibited values ranging from 15 to 175 MPa. Pre-existing dislocations percolated through the defect field but did not show (...) long-range motion, indicating that they are not responsible for creating the defect-free channels and have a limited contribution to the total plasticity. Defect-free channels were associated with the movement of many dislocations, which originated from grain boundaries or regions of high stress concentration such as at a crack tip. These experimental results are compared with atomistic simulations of the interaction of partial dislocations with defects in copper and a dispersed-barrier-hardening crystal plasticity model to correlate the observations to bulk mechanical properties. (shrink)
Thinkers like Slavoj Žižek and Tim Morton have heralded the end of our ideological constructions of nature, warning that popular “ecology” or the “natural” is just the latest opiate of the masses. Attempting to think what I call Nature after Nature, I turn to the Kamakura period Zen master Dōgen Eihei (1200–1253) to explore the possibilities of thinking Nature in its non-ideological self-presentation or what Dōgen called “mountains and rivers (sansui).” I bring Dōgen into dialogue with his great champion, the (...) American poet Gary Snyder (who understands the process of sansui as “the wild”), as well as with thinkers as diverse as Schelling, Kundera, Žižek, Agamben, and Muir. Beyond Nature being any one thing, what Badiou derides as the “cosmological one,” I argue for the reawakening and sobering up to multiple Nature, beyond its appearance as an object to a discerning subject, as the bioregions which give us our interdependent and dynamic being. (shrink)
This paper addresses the question of the earth. I center this effort on a reading of the figure of animality in the writings of Nietzsche and Bataille. I begin by accepting one of the decisive questions (die Entscheidungen) that Heidegger poses in the Beiträge zur Philosophie: "Whether nature is degraded to the exploitative place of calculation and furnishing and to an opportunity to 'have an experience' or whether nature as the self-closing Earth bears the opening of a world without image." (...) In an attempt to think the Earth, I argue that the human as a natural kind emerges in denial or flight from animality. Animality renders natural kinds porous. It does not congeal into a categorically delimitable operation, but rather interrupts and multiplies such operations. Moreover, they multiply them with what Nietzsche called "transvaluative" force. Animality contests the closure of a discourse on kinds of animals. (shrink)
This essay is devoted to an examination of the relationship between truth and laughter in the works of Nietzsche. My central text shall be the much malignedbook four of Zarathustra, with special attention paid to the braying of the ass. Laughter has been traditionally considered irrelevent to serious philosophical content and, at best, a stylistic quirk. I argue that this stems from a basic predjudice that is constitutive of a large part of the Western tradition, namely, the confusion of working (...) hard (a sine qua non for philosophy) with taking oneself seriously. I then analyze laughter in Nietzsche’s works as the voice of truth itself. Laughter is the affirmation of a register of truth as the other beginning that has been lost in every thing that begins. Such an analysis involves a discussion of the nature of both truth and laughter. In so doing, I also distinguish Nietzschean laughter from three representative and seminal accounts of laughter provided by Hobbes, Bergson, and Kant. (shrink)
Performance degradation of structural steels in nuclear environments results from the formation of a high number density of nanometre-scale defects. The defects observed in copper-based alloys are composed of vacancy clusters in the form of stacking fault tetrahedra and/or prismatic dislocation loops that impede the motion of dislocations. The mechanical behaviour of irradiated copper alloys exhibits increased yield strength, decreased total strain to failure and decreased work hardening as compared to their unirradiated behaviour. Above certain critical defect concentrations (neutron doses), (...) the mechanical behaviour exhibits distinct upper yield points. In this paper, we describe the formulation of an internal state variable model for the mechanical behaviour of such materials subject to these (irradiation) environments. This model has been developed within a multiscale materials-modelling framework, in which molecular dynamics simulations of dislocation?radiation defect interactions inform the final coarse-grained continuum model. The plasticity model includes mechanisms for dislocation density growth and multiplication and for irradiation defect density evolution with dislocation interaction. The general behaviour of the constitutive (homogeneous material point) model shows that as the defect density increases, the initial yield point increases and the initial strain hardening decreases. The final coarse-grained model is implemented into a finite element framework and used to simulate the behaviour of tensile specimens with varying levels of irradiation-induced material damage. The simulation results compare favourably with the experimentally observed mechanical behaviour of irradiated materials. (shrink)
The paper describes a novel transmission electron microscopy (TEM) experiment with in situ ion irradiation designed to improve and validate a computer model. TEM thin foils of molybdenum were irradiated in situ by 1?MeV Kr ions up to ?0.045 displacements per atom (dpa) at 80°C at three dose rates ?5???10?6, 5???10?5, and 5???10?4?dpa/s ? at the Argonne IVEM-Tandem Facility. The low-dose experiments produced visible defect structure in dislocation loops, allowing accurate, quantitative measurements of defect number density and size distribution. Weak (...) beam dark-field plane-view images were used to obtain defect density and size distribution as functions of foil thickness, dose, and dose rate. Diffraction contrast electron tomography was performed to image defect clusters through the foil thickness and measure their depth distribution. A spatially dependent cluster dynamic model was developed explicitly to model the damage by 1?MeV Kr ion irradiation in an Mo thin foil with temporal and spatial dependence of defect distribution. The set of quantitative data of visible defects was used to improve and validate the computer model. It was shown that the thin foil thickness is an important variable in determining the defect distribution. This additional spatial dimension allowed direct comparison between the model and experiments of defect structures. The defect loss to the surfaces in an irradiated thin foil was modeled successfully. TEM with in situ ion irradiation of Mo thin foils was also explicitly designed to compare with neutron irradiation data of the identical material that will be used to validate the model developed for thin foils. (shrink)
This paper provides a brief explanation and illustration of the phenomenon of semiotics. It then describes the conceptual tools of semiotics and how lawyers can use semiotics in law to create compelling arguments. Last, the paper applies the tools of semiotics to the Pennsylvania Supreme Court case Ferguson v. McKiernan, 940 A.2d 1236 (Pa. 2008), to reveal the shift in social context that made the lines of legal reasoning behind the outcome appear “self-evident.”.
As a result of irradiation, pressurized helium bubbles are observed in large number densities in some metals, which produce mechanical property changes. This paper presents the results of a computational multi-scale study (dislocation dynamics, DD, and molecular dynamics simulations, MD) to quantify the effect of He bubbles on material hardening from the impediment to dislocation motion. The effects of voids were studied using MD, and the effects of He bubbles, with a mean size of 2.5?nm and number densities from 3???1022?m?3 (...) to 6???1022?m?3, were investigated using DD over a range of internal He pressures ranging from 125 to 750?MPa. The MD simulations elucidated the dislocation pinning action of voids and bubbles. Also, within the range of parameters studied, the DD simulations showed a clear, but weak correlation between the number density of He bubbles, and the internal He pressure, on the flow stress of the metal. (shrink)
(2005). Atomic-level observation with three-dimensional atom probe of the solute behaviour in neutron-, ion- or electron-irradiated ferritic alloys. Philosophical Magazine: Vol. 85, Special Issue: Microstructural Processes in Irradiated Materials. Selected papers from the symposium held as part of the 2003 TMS Annual Meeting, San Diego, California, 2–6 March, 2003 Guest Editors: Charlotte S. Bequart, Robin E. Shäublin, Lance L. Snead and Brian D. Wirth, pp. 429-441.