Abstract This paper examines a fundamental, though relatively understudied, aspect of the physical theory of the physician Asclepiades of Bithynia, namely his doctrine of pores. My principal thesis is that this doctrine is dependent on a conception of void taken directly from Epicurean physics. The paper falls into two parts: the first half addresses the evidence for the presence of void in Asclepiades' theory, and concludes that his conception of void was basically that of Epicurus; the second (...) half focuses on the precise nature of Asclepiadean pores, and seeks to show that they represent void interstices between the primary particles of matter which are the constituents of the human body, and are thus exactly analogous to the void interstices between atoms within solid objects in Epicurus' theory. (shrink)
The void is deadly. If you were cast into a void, it would cause you to die in just a few minutes. It would suck the air from your lungs. It would boil your blood. It would drain the warmth from your body. And it would inflate enclosures in your body until they burst}.
Urban void sometimes amplifies alienation within urban space, and thus leads the way to the human craving for authenticity. Juxtaposing urban void with the conventional notion of urban objects, furthermore, conforms to Nietzsche's distinction between Dionysian and Apollonian deportment. The Apollonian is at the founding of the Platonic myth of the Ideal City and its modern descendant, the myth of the Rational City. Modern urban planning has been object-directed and, consistent with the historical trend since the Renaissance, has (...) become a constituent of a Neo-Platonic mythology that insists on forging a city as an urban technological artifact. Most existing urban parks and squares, as well as suburban gardens, within this approach, only augment the subordinate standing of urban voids. Yet the significance of urban void, as the unplanned place that represents the pre-rational, the genuine and the unadulterated, ought to lead to its re-introduction into city-form as a conduit for self-reflection and authenticity. Recognizing urban void for its significance may reintroduce an important Dionysian feature into city-form, leading to deliberate carving of authentic urban spaces. (shrink)
This is a preprint version, please do not quote without authorization. The final version has appeared as Stefano Franchi, "Palomar, the Triviality of Modernity, and the Doctrine of the Void,“ New Literary History, 28 (1997), 4, 757-778. See: http://muse.jhu.edu/journals/new_literary_history/toc/nlh28.4.html..
A multiple-slip dislocation-density-based formulation and computational schemes that are coupled to grain-boundary (GB) interfacial schemes and an internal porosity formulation are used to analyse the behaviour and interaction of different arrangements and geometries of explicit pairs of voids in a polycrystalline fcc aggregate. The GB regions are treated as regions with properties and topologies that are distinct from that of the grain bulk. The GB kinematic scheme accounts for dislocation density interactions with GBs, such as dislocation density impedance, blockage and (...) GB absorption. These evolving interfacial conditions are monitored throughout the deformation history. The analysis indicated that void-to-void interactions result in dislocation density evolution and saturation and porosity localization that are intricately related to both dislocation density pile-ups and blockages at GB interfaces, and GB absorption within different GB regions. (shrink)
What remains when you eliminate all matter? Can empty space-a void-exist? _Frank Close takes the reader on a lively and accessible tour through ancient ideas and cultural superstitions (including Aristotle, who insisted that the vacuum was impossible) to the frontiers of current scientific research. These newest discoveries tell us extraordinary things about the cosmos and may provide answers to some of our most fundamental questions: What lies outside the universe? If there was once nothing, then how did the universe (...) begin? (shrink)
The growth of duplex scales on iron-chromium alloys oxidised at 600°C in CO2-1 % CO gas is accompanied by the formation in the inner oxide layer of regularly-spaced lamellar voids parallel to the metal-oxide interface. It is proposed that these voids form at the metal-oxide interface by periodic condensation of vacancies which have been injected into the metal by the oxidation process. From lamellar void spacings, the vacancy fraction in the metal at condensation is estimated to be 6 ? (...) 10?3 and the energy to precipitate the first vacancy, E v, is ?2·7 ? 10?12 J. From consideration of surface energy changes accompanying lamellar void formation, an average value of E v= 1·3 ? 10?19 J is estimated. The effects of chromium content in the metal and specimen geometry on lamellar void spacings are consistent with the proposed mechanism. The presence of filamentary microcrystals of oxide in the lamellar voids suggests that the inner oxide grows by gas phase transport of the oxidant to the metal surface. (shrink)
Early experimental data on void swelling in electron-irradiated materials disagree with the dislocation bias models based on the dislocation-point defect elastic interactions. Later, this became one of the factors that prompted the development of models based on production bias (PBM) as the main driver for swelling, which assumed that the dislocation bias was much lower than that predicted by theoretical analyses of dislocation bias. However, the PBM in its present form fails to account for important and common observations, namely, (...) the indefinite void growth often observed under cascade irradiation and the swelling saturation observed under high-dose irradiation and in void lattices. In this paper, we show that these contradictions can be naturally resolved in the framework of the rate theory that accounts for the radiation-induced vacancy emission from extended defects, such as voids, dislocations and grain boundaries. This modification introduces a new bias type in the theory, namely, the emission bias. This modified rate theory agrees well with the experimental data and demonstrates that the original dislocation bias should be used in rate theory models along with the emission bias in different irradiation environments. The modified theory predictions include, but are not limited to, the radiation-induced annealing of voids, swelling saturation under high-dose irradiation, generally, and in void lattices, in particular. (shrink)
In their recent paper on void ordering, Barashev and Golubov 1 describe cavity lattice formation in austenitic steel under electron irradiation as a bubble lattice rather than a void lattice. While this is convenient for the model they propose, this comment gives several reasons why the bubble lattice assignation cannot be justified. In addition, some remarks made by Barashev and Golubov on the results of one-dimensional (1D) Monte Carlo simulations 2, and the role of 1D self-interstitial atom clusters (...) in creating the planar ordering found in experimental void lattice formation results 3, are critically discussed. (shrink)
This paper describes the use of simulation techniques to examine some of the processes involved in the alignment of voids under the influence of 2-dimensional self-interstitial atom (2-d SIA) transport. It follows an earlier paper in which the effects of 1-d SIA transport were investigated and uses similar methodology. In contrast to the 1-d SIA results, with 2-d SIA transport there is no difficulty in simulating the formation of simple cubic void lattices. In addition the work has been extended (...) to demonstrate the formation of perfect bcc and fcc void lattices. One important feature was that lattice formation took place some 100 times faster than found experimentally. The possibility that this might be due to a diluting effect of out of plane jumps was investigated but seemed very unlikely. This led to the alternative conclusion that the 2-d diffusing defect could not be the basic single interstitial but instead was a larger interstitial defect, such as a di-interstitial, present in far lower concentrations. One consequence of the new approach is that the phenomenon of void swelling would be essentially unaffected by the defect responsible for void lattice formation. This crucially avoids the fast swelling which, as suggested recently, might otherwise occur as void lattices form, and which would conflict with the often quoted association of void swelling saturation and void lattice formation. This association is now more likely to be controlled by a common factor such as high void density than by any direct mechanism. A possible explanation for the influence of impurities on void lattice formation in ion irradiated Nb, Nb-1%Zr, Ta, and Mo is discussed. (shrink)
In general terms, Social Presence is a feeling of togetherness regardless of spatial or temporal separation. It is a socioemotional attitude that reflexively centres on other people, via perceptions of their affective attitudes towards oneself. Communication technologies contribute to the maintenance of close personal relationships by facilitating welcome and timely socioemotional presence in the mind of an absent other. Presence of this kind may be ‘in the moment’ of communication and also persist over time, as it is ‘topped up’ through (...) repeated interactions. In this paper, we consider how type of personal relationship and degree of physical separation might condition the Social Presence value of a range of media. We report ratings of Closeness and Social Presence that were gathered over 21 days by 64 participants about the close personal relationships that were meaningful to them. We contrast the communication media they chose to use across four relationship types and whether separations were in the same or in a different city. Our findings are used to discuss new ways of thinking about the connection between people who care about one another, and the meaning of the void that separates them, through the time course of Social Presence and Closeness experiences. (shrink)
Over the last decade, molecular dynamics simulations of displacement cascades have revealed that glissile clusters of self-interstitial crowdions are formed directly in cascades and that they migrate one-dimensionally along close-packed directions with extremely low activation energies. Occasionally, under various conditions, a crowdion cluster can change its Burgers vector and glide along a different close-packed direction. The recently developed production bias model (PBM) of microstructure evolution under irradiation has been structured specifically to take into account the unique properties of the vacancy (...) and interstitial clusters produced in the cascades. Atomic-scale kinetic Monte Carlo (KMC) simulations have played a useful role in understanding the defect reaction kinetics of one-dimensionally migrating crowdion clusters as a function of the frequency of direction changes. This has made it possible to incorporate the migration properties of crowdion clusters and changes in reaction kinetics into the PBM. In the present paper we utilize similar KMC simulations to investigate the significant role that crowdion clusters can play in the formation and stability of void lattices. The creation of stable void lattices, starting from a random distribution of voids, is simulated by a KMC model in which vacancies migrate three-dimensionally and self-interstitial atom (SIA) clusters migrate one-dimensionally, interrupted by directional changes. The necessity of both one-dimensional migration and Burgers vectors changes of SIA clusters for the production of stable void lattices is demonstrated, and the effects of the frequency of Burgers vector changes are described. (shrink)
Taking up Kimberlé Crenshaw's conclusion that black feminist theorists seem to continue to find themselves in many ways “speaking into the void” (Crenshaw 2011, 228), even as their works are widely celebrated, I examine intersectionality critiques as one site where power asymmetries and dominant imaginaries converge in the act of interpretation (or cooptation) of intersectionality. That is, despite its current “status,” intersectionality also faces epistemic intransigence in the ways in which it is read and applied. My aim is not (...) to suggest that intersectionality cannot (or should not) be critiqued, nor do I maintain that celebratory applications/interpretations are immune from epistemic distortion when it comes to interpreting intersectionality. Rather, my goal is to demonstrate that critiques of intersectionality are one important site to examine hermeneutic marginalization and interpretive violence; the politics of citation; and the impact of dominant expectations or established social imaginaries on meaning-making. In so doing, I aim to consider more fully how entrenched ways of thinking are frequently relied upon to interpret and critique intersectionality, even as these are often the very frameworks that intersectionality theorists have identified as highly problematic tools of misrepresentation, erasure, and violation. This slippage away from intersectionality's outlooks, whether in critical or laudatory contexts, is a pivotal site of epistemic negotiation we must examine more closely. (shrink)
Strengthening due to voids can be a signi?cant effect of radiation damage in metals, but treatment of this by elasticity theory of dislocations is difficult when the mechanisms controlling the obstacle strength are atomic in nature. Results are reported of atomic-scale modelling to compare edge dislocation?void interaction in fcc copper and bcc iron. Voids of up to 6 nm diameter in iron and 8 nm diameter in copper were studied over the temperature range 0 to 600 K at different (...) applied strain rates. Voids in iron are strong obstacles, for the dislocation has to adopt a dipole-like configuration at the void before breaking away. The dipole unzips at the critical stress when the dislocation is able to climb by absorbing vacancies and leave the void surface. Dislocation dissociation into Shockley partials in copper prevents dislocation climb and affects the strength of small and large voids differently. Small voids are much weaker obstacles than those in iron because the partials break from a void individually. Large voids are at least as strong as those in iron, but the controlling mechanism depends on temperature. (shrink)
We have analyzed in detail the mechanism leading to tip growth on a surface which operates via nucleation of dislocations on a near-surface void under tensile surface stress. We derived a simplified analytical model describing the relevant physical factors related to the observed linearity between the void radius and the maximum depth of the void for the growth to occur. The model is based on the direct numerical calculation of atomic level stresses in the simulated system. Based (...) on the present model we can estimate this maximum depth for a void of a certain size under a given stress in the size range which is beyond the feasibility of the molecular dynamics simulation method. (shrink)
The process of fracture in ductile metals involves the nucleation, growth, and linking of voids. This process takes place both at the low rates involved in typical engineering applications and at the high rates associated with dynamic fracture processes such as spallation. Here we study the growth of a void in a single crystal at high rates using molecular dynamics (MD) based on Finnis?Sinclair interatomic potentials for the body-centred cubic (bcc) metals V, Nb, Mo, Ta, and W. The use (...) of the Finnis?Sinclair potential enables the study of plasticity associated with void growth at the atomic level at room temperature and strain rates from 109/s down to 106/s and systems as large as 128 million atoms. The atomistic systems are observed to undergo a transition from twinning at the higher end of this range to dislocation flow at the lower end. We analyse the simulations for the specific mechanisms of plasticity associated with void growth as dislocation loops are punched out to accommodate the growing void. We also analyse the process of nucleation and growth of voids in simulations of nanocrystalline Ta expanding at different strain rates. We comment on differences in the plasticity associated with void growth in the bcc metals compared to earlier studies in face-centred cubic (fcc) metals. (shrink)
Using the derived relation for point defect generation according to a new constitutive relation, the notion of nano-void formation at grown-in nano-particles is examined and its consequences deduced as the nano-voids grow in size with continued deformation. Assuming that void growth is due only to point defect accumulation, the analysis of fracture strains in tension of natural-aged AA6111 suggests that coalescence by micro-plastic activity occurs when the void diameter becomes about one third of the evolving inter-void (...) spacing. Hence, the derived limit strain to incipient void-coalescence is inversely proportional to the square root of point defect generation as determined from the stress?strain data. Using this criterion, failure prediction maps can be constructed for strain modes of plane-strain and balanced bi-axial to result in the outer bounds of the forming limit diagram. Trial examinations with AA5754 and AA3003 show great promise. (shrink)
The volume fraction of point defects generated as a function of plastic shear strain squared, ?2, was derived from crystal plasticity concepts. The evolution was determined from the stress?strain values using a new constitutive relation which replicates the measured behavior with at least two fitted loci. Assuming that nano-voids form by clustering of vacancies, the nano-void diameter was found to be proportional to their spacing and shear strain with the constant being characteristic of point defect production during deformation. The (...) predicted amount of point defect generated was validated using the previously determined resistivity of  copper single crystals deformed at 4.2?K and annealed at 296?K. Similar analysis of super-pure polycrystalline copper data affirmed that the dynamic annihilation parameter extrinsically incorporated in the new derivation is larger due to formation of slip clusters. Moreover, the temperature dependence of the mean slip-distance to inter-forest spacing ratio at Stage II to III transition indicates that the thermally activated drag of vacancy-creating jogs occurs above 150?K. For polycrystalline aluminum deformed at 296?K, it was concluded that the nuclei of the nano-voids were not part of the evolving dislocation array but were embedded in the grown-in microstructure. This hypothesis is pursued in the accompanying paper, Part II, and its prediction results in a criterion for ductile failure. (shrink)
In order to study the effect of grain size on void formation during high-energy electron irradiations, the steady-state point defect concentration and vacancy supersaturation profiles have been calculated for three-dimensional spherical grains up to three microns in size. In the calculations of vacancy supersaturation as a function of grain size, the effects of internal sink density and the dislocation preference for interstitial attraction have been included. The computations show that the level of vacancy supersaturation achieved in a grain decreases (...) with decreasing grain size. The grain size dependence of the maximum vacancy supersaturation in the centre of the grains is found to be very similar to the grain size dependence of the maximum void number density and void volume swelling measured in the central regions of austenitic stainless steel grains. This agreement reinforces the interpretation that the grain size effect is due primarily to the depletion of point defects from the grain interior. It is suggested that the void nucleation is strongly dependent on the level of vacancy supersaturation. (shrink)
Thin foils of an ? experimental ? austenitic stainless steel, with and without dispersions of aluminium oxide particles, are irradiated with 1 MeV electrons in a High Voltage Electron Microscope at 600°C. Evidence of grain size dependent void nucleation, void concentration, and void volume swelling are presented for grains in the size range 0°45 to ? 50 ?. In both undoped and helium-doped samples the void nucleation is delayed, void concentration is lowered, and void (...) volume swelling is reduced by decreasing the size of the grain under irradiation. The results are discussed in terms of a ? defect depletion ? model based on the property of grain boundaries as neutral and unsaturable sinks for vacancies and self-interstitials. It is suggested that even in the presence of sufficiently large amount of impurity gas atoms, a critical level of vacancy supersaturation is necessary to produce critically sized vacancy clusters which upon stabilization become viable void nuclei. It is concluded that the presence of stable and small grains improves the damage resistance of the material tremendously. (shrink)
This paper describes the use of simulation techniques to examine some of the processes involved in the alignment of voids under the influence of one-dimensional self interstitial atom (1-d SIA) transport. The work follows the paper of Heinisch and Singh  on this topic but a different and simpler methodology is used. Besides repeating the scenarios studied by Heinisch and Singh, the effects of re-nucleation and the influence of vacancies have been introduced. One of the important processes that emerged from (...) the results was the barrier to precise void alignment caused by the SIA-induced coalescence of aligned voids. This appears to prevent the formation of stable void lattices by any 1-d SIA transport mechanism, a point supported by the initial void alignment in the mechanism requiring swelling values well above those found experimentally. A full consideration of the void lattice phenomenon shows that the one-dimensional diffusion of self-interstitials central to the production bias model of irradiation damage cannot be the only mode of anisotropic diffusion available under irradiation. (shrink)
While agreeing with me on many issues, Revonsuo rejects my claim that phenomenal states could be co-conscious without being spatially related (in experience). In defence of my claim I described a thought-experiment in which.
From Han Yu’s yuan Dao 原道 (retracing the Dao) to Ouyang Xiu’s lun ben 论本 (discussing the root), the conflicts arising from Confucianists’ rejection of Buddhism were focused on one point, namely, the examination of zhongxin suo shou 中心所守 (something kept in mind). The attitude towards the distinction between mind and trace, and the proper approach to erase the gap between emptiness and being, as well as that between the expedient and the true, became the major concerns unavoidable for various (...) thinkers to integrate the two teachings and to propel academic development. To understand by mind and to blame for matter were of crucial methodological significance for transcendence in both Confucianism and Buddhism. The arguments of Confucian scholars like Zhang Zai and the Cheng brothers on the identity of mind and trace and the unity of void and solid are mutually manifested. The same mind with the same principle means mind is principle. The common axis of Confucianism and Buddhism exists in the emphasis on mind beyond trace. The unification of mind and trace or the accordance of body and function has actually become the cardinal foundation for the possible mergence of the Three Teachings. (shrink)
Based on the experiences of two high profile voluntary data collection programs for engineered nanomaterials, this article considers the merit of an international online registry for scientific data on engineered nanomaterials and environmental, health and safety (EHS) data. Drawing on the earlier experiences from the pharmaceutical industry, the article considers whether a registry of nanomaterials at the international level is practical or indeed desirable, and if so, whether such an initiative—based on the current state of play—should be voluntary or mandatory. (...) The article commences with an examination of the success and failures of voluntary reporting schemes in the UK and the US, as well as the International Council of Nanotechnology’s EHS Database and the OECD’s Working Party on Manufactured Nanomaterials. The article then examines the history of clinical trials registries, including the key motivations behind their creation, the role of self-regulation, and the perceived benefits thereof. Key lessons of the rise of clinical trials registration are highlighted, as are crucial considerations that must be addressed by policy makers should a multi-lateral public registry for data on nanoscale materials and EHS research be perceived to be a desirable option. The article concludes by arguing that while the creation of a registry to record information generated on nanomaterials is not straightforward, this reason alone should not deter industry from taking a proactive approach to the dissemination of fundamental data and research findings. (shrink)
In this paper I look at two connections between natural philosophy and theology in the late 17th century. In the last quarter of the century there was an interesting development of an argument, earlier but sketchier versions of which can be found in classical philosophers and in Descartes. The manoeuvre in question goes like this: first, prove that there must, necessarily, be a being which is, in some sense of "greater", greater than humans. Second, sketch a proof that such a (...) being is necessary. Move from the fact that there must be at least one such being to the conclusion that there is precisely one such being. Raise the question: could this necessary being be matter, the entire material universe, or must it be God? Produce an argument from natural philosophy to show that matter cannot be the required necessary being. Either explicitly or implicitly run the obvious disjunctive syllogism and conclude with a few remarks about the foolishness of atheism. The argument, which has classical roots, found a number of 17th-century exponents. Cudworth provided the most important version, and Locke, Bentley and Clarke adapted Cudworth's version with varying success. The argument touches on natural philosophy in two ways. First, the basis of the argument invites consideration of a problem in the philosophy of science - the relation between micro properties and macro properties - which was seen clearly enough in some contexts but which was overlooked in others, particularly when the theological aspect was uppermost. The second point of contact involves a direct application of a scientific result - the existence of a vacuum - to the theological issue. (shrink)
Murdoch brings together the darkness of misery and the darkness of wickedness under the observation that ‘goodness is not acontinuously active organic part of our purposes and wishes’. This looks like an empirically minded correction of Socrates. But besides correcting Socrates, is Murdoch also offering, as Stephen Mulhall suggests, ‘a fundamental counter-example’ to her own ‘moral vision’? This depends on what one takes Murdoch’s moral vision to be. I trace Mulhall's mistake to Maria Antonaccio's misidentification of the good with the (...) concept of the good. (shrink)
Although working through different traditions in European philosophy, the works of Giorgio Agamben and Slavoj Žižek have recently focused on issues surrounding the “state of emergency” that characterizes our age of increasing humanitarianism and global “police” actions. By investigating parallels in their separate diagnoses of our current political tendencies, this paper examines their suggestions for a political program of the future. Beginning with the paradoxes revealed in the ontological referent implied in “universal human rights,” this investigation will examine the contemporary (...) failure at developing a viable political ontology and the ensuing theoretical possibilities that these failures open for a politics of the future. (shrink)
Discussion of Iris Murdoch recalls Socrates' plea that he be allowed a crabwise approach to the Good. What his audience want of a direct approach is an explanation of precisely what sort of thing the Good is, where the demand for precision carries the force of: Tell me now, in which of the categories of thing I already allow to exist is the Good to be found? This is just what academia has done with the obscure singularity of Murdoch – (...) and the comedy of the exercise is the same. (shrink)
MANY moons from now, when extraterrestrial archeologists sift through the records of our brief civilization, they might be amused to stumble across the proceedings of an annual convention of stargazers called the American Astronomical Society. They would be right in concluding that 1996 was, in one way or another, a landmark year.