Cooking up consumer anxieties about ‘provenance’ and ‘ethics. Why it sometimes matters where foods come from in domestic provisioning

Provenance is fundamentally about foods' point of origin. It is thus, unsurprising that studies of food provenance typically focus on circumstances of production and the routes foods follow to get to situations of exchange and, to a lesser extent, final consumption. However, this dominant framing leads to an asymmetry of attention between production and consumption. By neglecting the situatedness of food purchase and use, much of what makes provenance meaningful and productive for consumers is missed. This paper draws upon qualitative and ethnographic data to explore why and how it sometimes matters where food comes from. What emerges is an expanded and problematized practical understanding of provenance, where concerns for the point of origin is generally inseparable from, and subsumed within, a broader range of ethical concerns about where food comes from

Placing power in practice theory

This chapter starts from a conviction that, to fulfil its potential, practice theory needs to be able to speak of power, and so it is worth seeking a compatible account of power. I also aim to establish some grounds for thinking about whether practice theory may have something distinctive to say about power; and consider to what good this might be put

Dual-mode model predictive control of an omnidirectional wheeled inverted pendulum

This article describes the position and heading control of a novel form of omnidirectional wheeled inverted pendulum platform known as a Collinear Mecanum Drive. This concept uses four collinear Mecanum wheels to balance in a similar manner to a typical two-wheeled inverted pendulum, whilst also being able to simultaneously translate directly along its balance axis. Control is performed using a constrained time-optimal infinite horizon model predictive controller, with feasibility maintained across the full reference input set. Explored in this article is the derivation of the system dynamics model and controller, a systematic approach to selection of controller parameters and analysis of their effect on control performance and complexity, and an evaluation of the controller's efficacy in both simulation and on a real-world experimental prototype for simple and complex trajectories

Velocity constrained trajectory generation for a collinear Mecanum wheeled robot

While much research has been conducted into the generation of smooth trajectories for underactuated unstable aerial vehicles such as quadrotors, less attention has been paid to the application of the same techniques to ground based omnidirectional dynamically balancing robots. These systems have more control authority over their linear accelerations than aerial vehicles, meaning trajectory smoothness is less of a critical design parameter. However, when operating in indoor environments these systems must often adhere to relatively low velocity constraints, resulting in very conservative trajectories when enforced using existing trajectory optimisation methods. This paper makes two contributions; this gap is bridged by the extension of these existing methods to create a fast velocity constrained trajectory planner, with trajectory timing characteristics derived from the optimal minimum-time solution of a simplified acceleration and velocity constrained model. Next, a differentially flat model of an omnidirectional balancing robot utilizing a collinear Mecanum drive is derived, which is used to allow an experimental prototype of this configuration to smoothly follow these velocity constrained trajectories

A reinterpretation of Volcano Ranch lateral distribution measurements to infer the mass composition of cosmic rays

In the course of its operation, the Volcano Ranch array collected data on the lateral distribution of showers produced by cosmic rays at energies above $10^{17}$ {\rm eV}. From these data very precise measurements of the steepness of the lateral distribution function, characterized by the $\eta$ parameter, were made. The current availability of sophisticated hadronic interaction models has prompted a reinterpretation of the measurements. We use the interaction models {\sc qgsjet} and {\sc sibyll} in the {\sc aires} Monte Carlo code to generate showers together with {\sc geant4} to simulate the response of the detectors to ground particles. As part of an effort to estimate the primary mass composition of cosmic rays at this energy range, we present the results of our preliminary analysis of the distribution of $\eta$.Comment: 4 pages, 5 figures Talk presented at the XII International Symposium on Very High Energy Cosmic Ray Interactions, CERN 2002. To be published in Nucl. Phys. B (Proc. Suppl.

Riemannian submersions from almost contact metric manifolds

In this paper we obtain the structure equation of a contact-complex Riemannian submersion and give some applications of this equation in the study of almost cosymplectic manifolds with Kaehler fibres.Comment: Abh. Math. Semin. Univ. Hamb., to appea

Design and control of a novel omnidirectional dynamically balancing platform for remote inspection of confined and cluttered environments

Remote inspection is a long standing field of interest for robotics researchers, in which robots are used to undertake inspection tasks in environments too hazardous or inaccessible to be directly entered by a human. Recent advances in gridscale battery storage have created a new set of unique hazardous indoor spaces with characteristics unsuitable for the deployment of existing teleoperated inspection robots. This paper outlines the problems encountered in these new environments, analyses existing approaches to robotic platform design, and proposes a better suited novel platform design, based on a dynamically balancing arrangement of Mecanum wheels. Its inverse kinematic and dynamics models are developed, a proof of concept prototype is constructed, and a constrained predictive controller is derived from the developed model. Experimental results demonstrate the efficacy of this new concept

New constraints on the mass composition of cosmic rays above 10^17 eV from Volcano Ranch measurements

Linsley used the Volcano Ranch array to collect data on the lateral distribution of showers produced by cosmic rays at energies above 10^17 eV. Very precise measurements of the steepness of the lateral distribution function were made on 366 events. The current availability of sophisticated hadronic interaction models has prompted an interpretation of the measurements. In this analysis we use the AIRES Monte Carlo code to generate showers, together with GEANT4 to simulate the detector response to ground particles. The results show that, with the assumption of a bi-modal proton and iron mix, iron is the dominant component of cosmic rays between 5x10^17 and 10^19 eV, assuming that hadronic interactions are well-described by QGSJET at this energy range.Comment: Submitted to Astropart. Phy

Quintessential Maldacena-Maoz Cosmologies

Maldacena and Maoz have proposed a new approach to holographic cosmology based on Euclidean manifolds with disconnected boundaries. This approach appears, however, to be in conflict with the known geometric results [the Witten-Yau theorem and its extensions] on spaces with boundaries of non-negative scalar curvature. We show precisely how the Maldacena-Maoz approach evades these theorems. We also exhibit Maldacena-Maoz cosmologies with [cosmologically] more natural matter content, namely quintessence instead of Yang-Mills fields, thereby demonstrating that these cosmologies do not depend on a special choice of matter to split the Euclidean boundary. We conclude that if our Universe is fundamentally anti-de Sitter-like [with the current acceleration being only temporary], then this may force us to confront the holography of spaces with a connected bulk but a disconnected boundary.Comment: Much improved exposition, exponent in Cai-Galloway theorem fixed, axionic interpretation of scalar explained, JHEP version. 33 pages, 3 eps figure