54,747 research outputs found
The stewardship of things: Property and responsibility in the management of manufactured goods
In the context of broad-based concerns about the need to move towards a more sustainable materials economy, particularly as they are expressed in debates around ecological modernisation (EM), we argue that product stewardship has radical potential as a means to promote significant change in the relationship between society and the material world. We focus on two important dimensions that have been neglected in approaches to product stewardship to date. Firstly, we argue that immanent within the basic concept of stewardship is a problematisation of dominant understandings of property ownership in neoliberal market economies. In the space opened up by notions of stewardship, different ways of enacting both rights and responsibilities to products and materials emerge which have potential to advance the sustainability of material economies. Secondly, through exploration of existing expressions of product stewardship, we uncover a neglected scale of action. Both policy and dominant articulations of EM focus primarily on the efficiency of production processes; and secondarily, the attitudes and behaviours of individual consumers. Missing from this is the 'meso-scale' of social collectives including households, neighbourhoods, more distributed communities and small scale social enterprises. Based on a review of existing research from Australia and the UK, including our own, we argue that understanding of embedded practices of material responsibility at the household scale can both reinvigorate the concept of product stewardship as a potentially radical intervention, and reveal the potential of the meso-scale as a challenging but worthwhile realm of policy intervention
Aspects of the confinement mechanism in Coulomb-gauge QCD
Phenomenological consequences of the infrared singular, instantaneous part of
the gluon propagator in Coulomb gauge are investigated. The corresponding quark
Dyson-Schwinger equation is solved, neglecting retardation and transverse
gluons and regulating the resulting infrared singularities. While the quark
propagator vanishes as the infrared regulator goes to zero, the frequency
integral over the quark propagator stays finite and well-defined. Solutions of
the homogeneous Bethe-Salpeter equation for the pseudoscalar and vector mesons
as well as for scalar and axial-vector diquarks are obtained. In the limit of a
vanishing infrared regulator the diquark masses diverge, while meson properties
and diquark radii remain finite and well-defined. These features are
interpreted with respect to the resulting aspects of confinement for colored
quark-quark correlations.Comment: 4 pages, 6 figure
Artificial Life XI: Proceedings of the Eleventh International Conference on the Simulation and Synthesis of Living Systems
A radial mode ultrasonic horn for the inactivation of <i>Escherichia coli</i> K12
Tuned cylindrical radial mode ultrasonic horns offer advantages over ultrasonic probes in the design of flow-through devices for bacterial inactivation. This study presents a comparison of the effectiveness of a radial horn and probe in the inactivation of Escherichia coli K12. The radial horn is designed using finite element analysis and the predicted modal parameters are validated using experimental modal analysis. A validated finite element model of the probe is also presented. Visual studies of the cavitation fields produced by the radial horn and probe are carried out using luminol and also backlighting to demonstrate the advantages of radial horns in producing a more focused cavitation field with widely dispersed streamers. Microbiological studies show that, for the same power density, better inactivation of E. coli K12 is achieved using the radial horn and, also, the radial horn offers greater achievable power density resulting in further improvements in bacterial inactivation. The radial horn is shown to be more effective than the probe device and offers opportunities to design in-line flow-through devices for processing applications
Generalized Affine Coherent States: A Natural Framework for Quantization of Metric-like Variables
Affine variables, which have the virtue of preserving the positive-definite
character of matrix-like objects, have been suggested as replacements for the
canonical variables of standard quantization schemes, especially in the context
of quantum gravity. We develop the kinematics of such variables, discussing
suitable coherent states, their associated resolution of unity, polarizations,
and finally the realization of the coherent-state overlap function in terms of
suitable path-integral formulations.Comment: 17 pages, LaTeX, no figure
Nitrogen transfer between clover and wheat in an intercropping experiment
A novel approach to the problem of improving nitrogen supply in organic farming is to use intercropping of cereals with a legume to provide nitrogen transfer within a season and/or to following crops. The affects of intercropping were studied in a column experiment using mixtures of winter wheat (Triticum aestivum cv. Claire), with white clover (w.c.) (Trifolium repens cv. Barblanca) and with red clover (r.c.) (Trifolium pratense cv. Britta). The effects of cutting and removal above ground clover material with and without additional soil disturbance were compared to leaving clover plants in situ and intercropped with wheat in a split root design. Wheat and clover plants, as monocultures, were used for the controls. 15N ammonium nitrate solution was applied. The wheat seeds were sown into the column without nitrogen. We found that the cutting treatment produced the highest yield of wheat. Available ammonium-N in the soil was greatest in the clover control treatment for the column with only red clover roots and in the cutting+soil disturbance treatment for the column with only white clover roots. Available nitrate-N was greatest in the soil disturbance treatment in the column with clover and wheat roots for both red and white clover. The cutting treatment produced the highest yield of wheat
Present state of knowledge of the upper atmosphere 1988: An assessment report
This document was issued in response to the Clean Air Act Amendments of 1977, Public Law 95-95, mandating that NASA and other key agencies submit biennial reports to Congress and EPA. NASA is to report on the state of our knowledge of the upper atmosphere, particularly the stratosphere. This is the sixth ozone assessment report submitted to Congress and the concerned regulatory agencies. Part 1 contains an outline of the NASA Upper Atmosphere Research Program and summaries of the research efforts supported during the last two years. An assessment is presented of the state of knowledge as of March 15, 1988 when the Ozone Trends Panel, organized by NASA and co-sponsored by the World Meteorological Organization, NOAA, FAA and the United Nations Environment Program released an executive summary of its findings from a critical in-depth study involving over 100 scientists from 12 countries. Chapter summaries of the International Ozone Trends Panel Report form the major part of this report. Two other sections are Model Predictions of Future Ozone Change and Chemical Kinetics and Photochemical Data for Use in Stratospheric Modeling. Each of these sections and the report in its entirety were peer reviewed
Principal component analysis-based inversion of effective temperatures for late-type stars
We show how the range of application of the principal component
analysis-based inversion method of Paletou et al. (2015) can be extended to
late-type stars data. Besides being an extension of its original application
domain, for FGK stars, we also used synthetic spectra for our learning
database. We discuss our results on effective temperatures against previous
evaluations made available from Vizier and Simbad services at CDS.Comment: Accepted for publication in A&
Evaluation of a Multizone Impedance Eduction Method
A computational study is used to evaluate the PyCHE impedance eduction method developed at the NASA Langley Research Center. This method combines an aeroacoustic duct propagation code based on numerical solution to the convected Helmholtz equation with a global optimizer that uses the Differential Evolution algorithm. The efficacy of this method is evaluated with acoustic pressure data simulated to represent that measured with one-zone, two-zone, and three-zone liners mounted in the NASA Langley Grazing Flow Impedance Tube. The PyCHE method has a normalized impedance error of approximately 0.2 for (uniform) one-zone liners with a length of at least 5, and produces quite reasonable results for liners as short as 2. Whereas the impedance of the liner has an effect on eduction accuracy, the amount of attenuation is shown to be the dominant parameter. Similar results are observed for two-zone liners, for which the impedance of each zone is unique. The two-zone results also indicate it is more difficult to accurately educe resistance than reactance, and a zone length of at least 6 (slightly longer than for uniform liners) is needed to limit the normalized error to 0.2. The PyCHE method is also demonstrated to successfully educe the impedances for each zone of a three-zone liner. These results are sufficiently encouraging to warrant the continued usage of the PyCHE impedance eduction method for single and multizone liners
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