Nos\'e-Thermostated Mechanical Systems on the n-Torus

Let $H(q,p) = \frac12 | p |^2 + V(q)$ be an $n$-degree of freedom $C^r$ mechanical Hamiltonian on the cotangent bundle of the $n$-torus where $r>2n+2$. When the metric $| * |$ is flat, the Nos\'e-thermostated system associated to $H$ is shown to have a positive-measure set of invariant tori near the infinite temperature limit. This is shown to be true for all variable mass thermostats similar to Nos\'e's, too. These results complement results of Legoll, Luskin & Moeckel and the author.Comment: 11 page

Design Spectrum Analysis in NASTRAN

The utility of Design Spectrum Analysis is to give a mode by mode characterization of the behavior of a design under a given loading. The theory of design spectrum is discussed after operations are explained. User instructions are taken up here in three parts: Transient Preface, Maximum Envelope Spectrum, and RMS Average Spectrum followed by a Summary Table. A single DMAP ALTER packet will provide for all parts of the design spectrum operations. The starting point for getting a modal break-down of the response to acceleration loading is the Modal Transient rigid format. After eigenvalue extraction, modal vectors need to be isolated in the full set of physical coordinates (P-sized as opposed to the D-sized vectors in RF 12). After integration for transient response the results are scanned over the solution time interval for the peak values and for the times that they occur. A module called SCAN was written to do this job, that organizes these maxima into a diagonal output matrix. The maximum amplifier in each mode is applied to the eigenvector of each mode which then reveals the maximum displacements, stresses, forces and boundary reactions that the structure will experience for a load history, mode by mode. The standard NASTRAN output processors have been modified for this task. It is required that modes be normalized to mass

Understanding digital eco-innovation in municipalities: An institutional perspective

Municipalities consume over 67% of global energy and are responsible for over 70% of greenhouse gas emissions (GHG). The Intergovernmental Panel on Climate Change warns that rapid adjustments need to happen at a global level, or the effects of climate change will be irreversible. The contribution of municipalities is therefore vital if GHG emissions are to be reduced. Our research is timely in its exploration of the ways in which municipalities institutionalise environmental sustainability practices in and through Green digital artefacts. Using mechanism-based institutional theory as a lens, the paper presents the findings of three contrasting case studies of large municipalities in the United Kingdom in their respective programmes to leverage the direct, enabling and systemic effects of Green ICT in order to reduce GHG emission and achieve their eco-sustainability goals. The case sites are also regarded as exemplars for further research and practice on digital eco-innovation. The mechanism-based explanations illustrate how a social web of conditions and factors influence eco-sustainability outcomes. We conclude that the digital technology-enabled grassroots-based initiatives offer the best hope to begin the transition to sustainable climate change within municipalities. The contributions of our study are therefore both theoretical and practical

Condensing loaded points for transients by substructuring

A technique for condensing dynamic loading points is described. The method was applied to substructure transient solutions and was found to be very effective

Socio-technical transitions towards environmental sustainability through green ICT

We adopt the broad conceptualisation of Green Information Communication Technology (ICT) used by the Organisation for Economic Cooperation and Development (OECD), incorporating perspectives on Information Technology (IT) and Information Systems (IS) which has currency with both business practitioners and policy makers. The objective of our research is to develop a theory of the institutional mechanisms that underpin socio-technical transitions to environmental sustainability through the direct, indirect and systematic effects of Green ICT in and across organisational fields. We construct our theory by drawing on published research in several disciplines focusing on the organisational field of the ICT industry. We present a mechanism-based theoretical model that explains how institutional change in organisational fields can evoke appropriate socio-technical transitions and organisational responses to Green ICT. Systems researchers agree that Green ICT can help lower GHG emissions directly, through energy efficiencies and indirectly by enabling environmentally sustainable business processes. If this research is to be of theoretical or practical relevance it must recognize that government organizations and business enterprises may not adopt policies and strategies on Green ICT because it is rational or moral to do so rather, a web of social, and institutional mechanisms interact to produce the outcomes observed in practice