407 research outputs found
On the Ontology of Particle Mass and Energy in Special Relativity
Einstein claimed that the fundamental dynamical insight of special relativity was the equivalence of mass and energy. I disagree. Not only are mass and energy not equivalent (whatever exactly that means) but talk of such equivalence obscures the real dynamical insight of special relativity, which concerns the nature of 4-forces and interactions more generally. In this paper I present and defend a new ontology of special relativistic particle dynamics that makes this insight perspicuous and I explain how alleged cases of mass--energy conversion can be accommodated within that ontology
On the Ontology of Particle Mass and Energy in Special Relativity
Einstein claimed that the fundamental dynamical insight of special relativity was the equivalence of mass and energy. I disagree. Not only are mass and energy not equivalent (whatever exactly that means) but talk of such equivalence obscures the real dynamical insight of special relativity, which concerns the nature of 4-forces and interactions more generally. In this paper I present and defend a new ontology of special relativistic particle dynamics that makes this insight perspicuous and I explain how alleged cases of mass--energy conversion can be accommodated within that ontology
Agro-climate tools for a new climate-smart agriculture
The way we produce food must adapt to a variable and changing climate. And key to achieving this is to improve the link between climate information and agricultural practices, especially those of smallholder farmers in developing countries. ‘Agro-climate tools’ do just that and some are introduced here
Synopsis of the Robert and Sarah Boote Conference in Reductionism and Anti-Reductionism in Physics
This document is a synopsis of discussions at the workshop prepared by Nicholaos Jones and Kevin Coffey, with remarks added by by Chuang Liu, John D. Norton, John Earman, Gordon Belot, Mark Wilson, Bob Batterman and Margie Morrison. The program is included in an appendix
Synopsis of the Robert and Sarah Boote Conference in Reductionism and Anti-Reductionism in Physics
This document is a synopsis of discussions at the workshop prepared by Nicholaos Jones and Kevin Coffey, with remarks added by by Chuang Liu, John D. Norton, John Earman, Gordon Belot, Mark Wilson, Bob Batterman and Margie Morrison. The program is included in an appendix
Towards an improved understanding of knowledge dynamics in integrated coastal zone management: a knowledge systems framework
Integrated coastal zone management (ICZM) is a complex undertaking that draws on a range of biophysical and social science disciplines, and involves a wide range of stakeholders operating through multiple processes, and crossing various levels Conceptually, this means that ICZM represents a significant challenge in terms of improving the way in which different disciplinary ‘knowledges’ and different forms of knowledge (scientific, managerial, lay, and indigenous) inform decision making. Depending upon the circumstances, ICZM may be constrained by different knowledge deficits, including: uncertainty; science - policy gaps; and the ‘filtering’ of particular forms of knowledge relative to others. As a means for making sense of these knowledge dynamics, this paper considers the concept of knowledge systems and its potential for improving understanding of coastal management processes. The potential insights that can be gained from four analytical approaches (stakeholder, institutional, network, and discourse analysis) are then discussed, and used to develop an analytical framework for investigating coastal knowledge dynamics, which is based upon a generic coastal knowledge system and associated research questions. Finally, the utility of this framework is illustrated using a case study that examines the knowledge dynamics associated with debates about the establishment of marine protected areas in Victoria, Australia
Thickness dependence of structure and magnetic properties of annealed Fe/Pt (n) multilayer films
The L1(0) FePt phase material has potential applications for magnetic recording and permanent magnets due to its high magnetocrystalline anisotropy energy density. The heat treatment of [Fe/Pt](n) multilayer films is one approach to form the L1(0) FePt phase at a lower processing temperature, which is highly desirable for its applications. This paper reports the influence of film total thickness (8-100 nm) on the structure and magnetic properties of annealed [Fe/Pt](n) multilayer films. A novel technique based on hollow cone dark field transmission electron microscopy is used to determine the L1(0) phase fraction and grain size in the annealed films. It was found that the L1(0) phase fraction and grain size, ordering, and magnetic properties are strongly dependent on the total film thicknesses. An L1(0) FePt phase fraction close to 100% is achieved for a thick [Fe/Pt](n) multilayer film (100 nm) annealed at 400 degrees C for 1 h, while a value of only 36% is achieved for a thin film (8 nm) annealed at the same condition. In this work the L1(0) FePt phase nucleation density is also presented. These results suggest that the L1(0) phase formation is nucleation limited, and that the subsequent growth of L1(0) phase grains also strongly influences the structure and magnetic properties of the annealed films
The effective interdiffusivity, structure, and magnetic properties of Fe/Pt (n) multilayer films
This paper reports the influence of the deposition temperature and the wavelength of the periodicity on the effective interdiffusivity, microstructure, and magnetic properties of annealed [Fe/Pt](n) multilayer films (MLs). It was found that both the deposition temperature and periodicity of [Fe/Pt](n) MLs have a significant influence on the effective Fe-Pt interdiffusivity, microstructure, and magnetic properties of the annealed films. It was also observed that the magnitude of the effective interdiffusion coefficient, the L1(0) grain size, and the long-range order parameter were positively correlated. This result suggests that nonequilibrium reaction kinetics are desirable for the reduced temperature formation of the L1(0) FePt phase
Quantification of L1(0) phase volume fraction in annealed Fe/Pt (n) multilayer films
The heat treatment of [Fe/Pt](n) multilayer films is a promising approach to form the L1(0) FePt phase at a reduced temperature, which is of interest for applications as high-density magnetic recording media and high-energy permanent magnets. The volume fraction of the L1(0) FePt phase in the annealed films strongly influences their magnetic properties. This paper introduces a novel method based on hollow cone dark field transmission electron microscopy imaging to quantify the L1(0) FePt phase volume fraction. This method is used to characterize two sets of [Fe/Pt](n) multilayer films with varying deposition temperature and periodicity. It was found that both the deposition temperature and bilayer periodicity are significant to the structure and magnetic properties of annealed films and to the extent to which the L1(0) phase is formed. A correlation between L1(0) phase volume fraction, grain size, and magnetic properties was also observed
Ignitable Heterogeneous Structure and Methods for Forming
A metastable intermolecular composite (MIC)and methods for forming the same includes a first material and a second ma terial having an interfacial region therebetween. The first and second material are capable of an exothermic chemical reaction with one another to form at least one product and are in sufficiently close physical proximity to one another so that upon initiation the exothermic reaction develops into a self initiating reaction. At least one of said first and second materials include a metal that is reactive with water vapor at room temperature. The interfacial region averagesthick, such asembodiment, the first material is Al and the second material is CuOx
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