The buckling and collapse behaviour of saddle-supported cylinders - Keynote Lecture

Recent work by the present authors on the collapse conditions for horizontal cylindrical saddle supported storage vessels is described and reviewed. Attention is directed to a range of geometries, typically R/t < 200, where plastic collapse type failure may be relevant. A series of forty tests on end-supported model cylinders loaded centrally by a rigid saddle were performed and a variety of theoretical methods were used for comparison with the test results. It was found that the best agreement was obtained by using an elasticplastic finite element analysis approach. The results of a parametric survey based on the elastic-plastic finite element method are summarised. The paper reports some validation checks, which have been performed to support the parametric results

Parametric plastic collapse loads and their validation for horizontal saddle supported storage vessels

In general, progressive plastic collapse occurs in vessels with low values of R/t ratio, typically less than 200, and elastic-plastic buckling is observed in vessels with higher R/t ratios. The aim of this paper is to examine various theoretical analyses for plastic collapse loads, applicable to vessels with low values of R/t ratio, and compare these with the experimental results obtained by the authors and others

The strongly regular (45,12,3,3) graphs

Using two backtrack algorithms based on dierent techniques, designed and implemented independently, we were able to determine up to isomorphism all strongly regular graphs with parameters v = 45, k = 12, &#955; = &#956; = 3. It turns out that there are 78 such graphs, having automorphism groups with sizes ranging from 1 to 51840

Visuo-tactile links in covert exogenous spatial attention remap across changes in unseen hand posture

We investigated the effect of unseen hand posture on cross-modal, visuo-tactile links in covert spatial attention. In Experiment 1, a spatially nonpredictive visual cue was presented to the left or right hemifleld shortly before a tactile target on either hand. To examine the spatial coordinates of any cross-modal cuing, the unseen hands were either uncrossed or crossed so that the left hand lay to the right and vice versa. Tactile up/down (i.e., index finger/thumb) judgments were better on the same side of external space as the visual cue, for both crossed and uncrossed postures. Thus, which hand was advantaged by a visual cue in a particular hemifield reversed across the different unseen postures. In Experiment 2, nonpredictive tactile cues now preceded visual targets. Up/down judgments for the latter were better on the same. side of external space as the tactile cue, again for both postures. These results demonstrate cross-modal links between vision and touch in exogenous covert spatial attention that remap across changes in unseen hand posture, suggesting a modulatory role for proprioception

On the plastic collapse of horizontal saddle supported storage vessels

The present paper summarises a comprehensive programme of work on collapse loads of horizontal cylindrical saddle supported storage vessels. A programme of tests was conducted on 40 model vessels that included both welded and loose saddles. Different collapse behaviours were observed depending largely on the radius to thickness ratio of the vessels. A range of theoretical approaches were explored and compared with the experimental results. The best theoretical comparison was then used to conduct a parametric survey covering a total of 218 cases. The results of the survey have been presented in the form of simple design graphs

Horizontal saddle-supported storage vessels: A parametric study of plastic collapse loads

Previous work by the present authors compared various theoretical methods with simple experiments for the plastic collapse load on end supported vessels loaded centrally by rigid saddles. It was found that the best agreement was obtained by using an elastic-plastic finite element analysis approach. In the present paper the elastic-plastic method has been used to examine the effect of various geometric parameters on the collapse load. A symmetrical model which replicated the geometric features of the experiments can be used to give an indication of the effect of specific isolated geometric variables but for others and for the purposes of undertaking a full parametric survey the model was modified to reflect an actual twin saddle supported vessel

Entrepreneurial dynamics and social responsibility: mapping an expanded intellectual territory

Objectives: (1) To provide a constructive critique of the interface between the entrepreneurial growth dynamics research and social responsibility literatures; (2) to explore opportunities for making new connections between these literatures in order to address substantive ‘gaps’ in research and policy-making ; (3) to map the broader intellectual territory implied by this critique; (4) to outline a tentative research agenda. Prior work: The paper draws on two main strands of research: entrepreneurial growth dynamics and (corporate) social responsibility. While much has been achieved in the social responsibility literature with regards to established practices, we argue that insufficient attention has been paid to the more ‘entrepreneurial’ dimensions. At the same time, the current wave of enthusiasm for new models of socially-responsible enterprise has opened up a series of new research questions, including: (i) how are these organisational forms likely to grow and develop over the longer-term, at an intra-organisational level, and in terms of emerging inter-organisational relationships?; (iii) how will other actors respond to these developments?; (ii) what are the implications of the resulting dynamics for social, environmental and economic sustainability? Approach: The paper is based around a critical review of the relevant literatures, focusing on the role of entrepreneurial opportunity and capabilities in shaping entrepreneurial growth dynamics. The discussion addresses current methodological debates and considers how social responsibility can be integrated into the analysis. In doing so, it builds on a research tradition that has promoted historically-informed multi-level and co-evolutionary analysis and argues that such techniques are required in order to gain a better understanding of these phenomena. Results: We outline a research agenda, illustrated with a number of questions of particular relevance to researchers, policy-makers and practitioners Implications: The paper identifies a number of issues for researchers and policy-makers and practitioner audiences. It calls for a broadening of the intellectual territory around socially-responsible enterprise. Process-based and multi-level analysis of growth dynamics extends its temporal and organisational boundaries to encompass longer-term interactions and a wider range of actors. Value: The paper is designed to facilitate and to encourage more constructive interaction between research communities concerned with: social responsibility, social enterprise and process-based approaches to entrepreneurship. It advances understanding by mapping an intellectual space that is neither fully revealed in, nor adequately addressed by, existing bodies of knowledge

Are periodic solar wind number density structures formed in the solar corona?

[1] We present an analysis of the alpha to proton solar wind abundance ratio (AHe) during a period characterized by significant large size scale density fluctuations, focusing on an event in which the proton and alpha enhancements are anti-correlated. In a recent study using 11 years (1995–2005) of solar wind observations from the Wind spacecraft, N. M. Viall et al. [2008] showed that periodic proton density structures occurred at particular radial length-scales more often than others. The source of these periodic density structures is a significant and outstanding question. Are they generated in the interplanetary medium, or are they a relic of coronal activity as the solar wind was formed? We use AHe to answer this question, as solar wind elemental abundance ratios are not expected to change during transit. For this event, the anti-phase nature of the AHe variations strongly suggests that periodic solar wind density structures originate in the solar corona