Practical Forecasting of AC Losses in Multi-layer 2G-HTS Cold Dielectric Conductors

With the recent progresses on the designing and manufacturing of lightweight and high engineering current density superconducting cables, the need for an established, fast, and sufficiently accurate computational model for the forecasting of AC-losses in cold-dielectric conductors, is pivotal for increasing the investment confidence of power grid operators. However, validating such models is not an easy task, this because on the one hand, there is a low availability of experimental results for large scale power cables and, on the other hand, there is a large number of 2G-HTS tapes involved whose cross-sectional aspect ratio hinders the numerical convergence of the models within reasonable delivery times. Thus, aiming to overcome this challenge, we present a detailed two-dimensional H-model capable to reproduce the experimentally measured AC-losses of multi-layer power cables made of tens of 2G-HTS tapes. Two cable designs with very high critical currents have been considered, the first rated at 1.7 kA critical current, consisting of fifty 4 mm width 2G-HTS tapes, these split in 5 concentric layers wound over a cylindrical former, with the three inner layers forming an arrangement of 24 tapes shielded by two further layers with 13 tapes each. This cable is contrasted with a size wise equivalent cable with 67 superconducting tapes rated at 3.2 kA critical current, whose design implies the use of 40 tapes of 3 mm width split within four core layers, and 27 tapes of 4 mm width distributed in two shielding layers. In both situations a remarkable resemblance between the simulations and experiments has been found, rendering to acceptable estimates of the AC-losses for cold dielectric conductors, and offering a unique view of the local electrodynamics of the wound tapes where the mechanisms of shielding, magnetization, and transport currents can coexist within the hysteretic process.Comment: 4 Figures, 6 page

The use of genetic algorithms to maximize the performance of a partially lined screened room

This paper shows that it is possible to use genetic algorithms to optimize the layout of ferrite tile absorber in a partially lined screened enclosure to produce a "best" performance. The enclosure and absorber are modeled using TLM modeling techniques and the performance is determined by comparison with theoretical normalized site attenuation of free space. The results show that it is possible to cover just 80% of the surface of the enclosure with ferrite absorber and obtain a response which is within +/-4 dB of the free space response between 40 and 200 MHz

Colloidal templating at a cholesteric - oil interface: Assembly guided by an array of disclination lines

We simulate colloids (radius $R \sim 1\mu$m) trapped at the interface between a cholesteric liquid crystal and an immiscible oil, at which the helical order (pitch p) in the bulk conflicts with the orientation induced at the interface, stabilizing an ordered array of disclinations. For weak anchoring strength W of the director field at the colloidal surface, this creates a template, favoring particle positions eitheron top of or midway between defect lines, depending on $\alpha = R/p$. For small $\alpha$, optical microscopy experiments confirm this picture, but for larger $\alpha$ no templating is seen. This may stem from the emergence at moderate W of a rugged energy landscape associated with defect reconnections.Comment: 5 pages, 4 figure

Scalable Peer-to-Peer Streaming for Live Entertainment Content

We present a system for streaming live entertainment content over the Internet originating from a single source to a scalable number of consumers without resorting to centralized or provider-provisioned resources. The system creates a peer-to-peer overlay network, which attempts to optimize use of existing capacity to ensure quality of service, delivering low startup delay and lag in playout of the live content. There are three main aspects of our solution: first, a swarming mechanism that constructs an overlay topology for minimizing propagation delays from the source to end consumers; second, a distributed overlay anycast system that uses a location-based search algorithm for peers to quickly find the closest peers in a given stream; and finally, a novel incentive mechanism that encourages peers to donate capacity even when the user is not actively consuming content

Accounting as practice

In this paper we seek to debate some of the problems affecting positivist accounting research, and how the adoption of organizational theory grounded on qualitative methods can fruitfully contribute to advance research in the area. To this end we draw on research we have previously conducted in Portuguese public hospitals to discuss how the incorporation of power issues, institutional entrepreneurship, hybridization, institutional logics and institutional work in accounting studies fosters in-depth explanations of accounting practice.info:eu-repo/semantics/publishedVersio

Politicization and political contests in and around contemporary multinational corporations: An introduction

© 2018, © The Author(s) 2018. This article looks at core arguments in international business, organization studies and surrounding academic fields that focus on the study of politicization and political contests in and around multinational corporations (MNCs). Two evident streams of debate are identified. Equally evident is that these streams hardly connect. One stream is mainly interested in studying politicization from the outside, whereas the other is mainly interested in politicization from within. As a way of connecting both streams, we introduce the circuits of power framework. Next, we introduce the contributions of our Special Issue, followed by concluding comments which distinguish five emergent themes. First, we show how the application of the circuits of power framework sheds new light on the study of political contests of MNCs. Second, we highlight that the role of nation states has not lost its significance as, for example, political corporate social responsibility (CSR) approaches would have us believe. Third, dominant ideologies play an important role in establishing and controlling circuits of power in and around MNCs. Fourth, it is vital to take labour issues into account in this field of study. Fifth, there is increasing evidence that asymmetric and hierarchical forms of organizing do not disappear in new MNC network forms

Management, Organizations and Contemporary Social Theory

Social theorists speculate about large-scale social questions, asking of any phenomenon, how is it possible? This book addresses how various social theories contribute key insights into the nature of organizations and management

Oral versus intubated feeding and the effect on glycaemic and insulinaemic responses, gastric emptying and satiety

Cephalic phase responses (CPR) are important in early initiation of digestion and maximal absorption of nutrients prior to ingestion. Bypassing CPR has been shown to have consequences on metabolic responses that may influence satiety. The aim of this study was to investigate if using gastric intubation to bypass oro-pharyngeal and oesophageal exposure would reduce CPR including insulin and blood glucose and whether these impact on gastric emptying and satiety. Ten male subjects were tested on 2 occasions, 3-7 days apart after an overnight fast, in randomized order. Subjects were cannulated and intubated with a gastric tube for both tests. For test one, subjects ate 400 ml soup with a spoon and for test two the soup was infused into the stomach at an equivalent rate. Subsequently measurements of glycaemic (GR) and insulinaemic responses (IR) from cannula samples, breath samples for measurement of gastric emptying using the [(13)C] sodium acetate breath test and visual analogue scales (VAS) for satiety were taken over 180 min. There were differences in IR over the first 15 min (Oral: 169.0 +/- 22.1; Gastric 124.1 +/- 18.8; t(9) = 2.67; p = 0.028) but no difference in GR. There were differences in gastric emptying half time (Oral: 85.0 +/- 2.7; Gastric 79.4 +/- 3.3; t(9) = 2.40; p = 0.04) and ascension time (Oral: 68.2 +/- 2.2; Gastric 64.0 +/- 2.2; t(9) = 2.57; p = 0.03) with food taking longer to empty from the stomach on the Oral test day than on the Gastric test day. There was no significant difference in the satiety ratings. This study demonstrated that bypassing oro-pharyngeal and oesophageal exposure decreases the normal physiological CPR with detriment to IR and gastric emptying