6,194 research outputs found
Neutron Scattering and magnetization studies of BaCuCoOCl: A decorated two-dimensional antiferromagnet
BaCuOCl has two inter-penetrating square Cu sublattices, one
with square root 2 times the in-plane spacing of the other. Isotropic magnetic
interactions between the two sublattices are completely frustrated. Quantum
fluctuations resolve the intrinsic degeneracy in the ordering direction of the
more weakly coupled sublattice in favor of collinear ordering. We present
neutron scattering and magnetization studies of the magnetic structure when the
Cu ions are substituted with Co. The Co spins create new magnetic interactions
between the two sublattices. The ordering behavior of both Cu sublattices is
retained largely unmodified. Between the phase transitions of the two
sublattices spin-glass behavior is observed. Magnetization results show a
strong enhancement to the ferromagnetic aspect of the magnetic structure. The
combination of glassy behavior and large moments strongly suggest that the Co
moments induce the formation of local canted states.Comment: 4 figure
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 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
. For small , optical microscopy experiments confirm this
picture, but for larger 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
Reflections on phronetic social science: a dialogue between Stewart Clegg, Bent Flyvbjerg and Mark Haugaard
Clegg, Flyvbjerg and Haugaard debate the strengths and weaknesses of a Foucauldian-Nietzschean critique of power compared to a tradition exemplified by Lukes and Habermas. Flyvbjerg and Clegg argue that the pursuit of universal normative principles and of rationality without power may lead to oppressive utopian thinking. Drawing on the Aristotelian tradition of phronesis, they propose a contextualist form of critique that situates itself in analysis of local practices to render domination transparent and open to change. While Haugaard accepts there cannot be a universal view that transcends the particularities of context, he argues that the phronetic approach is crypto-normative because it implicitly presupposes unacknowledged liberal normative premises; moreover, any use of 'truth' as a criterion follows Enlightenment principles of verification. © 2014 Taylor & Francis
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
- …