2019
Autores
Ferreira, TD; Silva, NA; Guerreiro, A;
Publicação
FOURTH INTERNATIONAL CONFERENCE ON APPLICATIONS OF OPTICS AND PHOTONICS
Abstract
This paper proposes the use of nematic liquid crystals as tunable setups to implement optical analogues of physical systems and phenomena that are hard or even impossible to study experimentally under controlled conditions. Optical analogues share the same physical model with the systems that they emulate and can be understood as a form of physical simulations or optical computation. However, their success relies not only on the existence of media with optical properties capable of emulating the models associated with the original system as they interact with light, but also on the possibility of being able to tune those properties in order to cover the multitude of conditions or range of parameters. In particular, the Schrodinger-Newton model is a good target for this kind of studies as it can describe a plethora of different phenomena in physics and can be implemented in the laboratory using optical analogues, usually using thermo-optical materials. However, such materials have limitations, and in this work we propose nematic liquid crystals as a more advantageous alternative. We discuss how nematic liquid crystals can be used as a tunable support medium for optical analogues of superfluids by analyzing the dispersion relation of light under specific conditions and using numerical simulations based on GPGPU supercomputing to verify our findings. Extending on this, we explore more direct manifestations of superfluid effects in nematic liquid crystals, such as drag-force cancellation in the superfluid regime and the possibility of creating a roton-minimum in the dispersion relation.
2019
Autores
Javadi, MS; Razavi, SE; Ahmadi, A; Siano, P;
Publicação
RENEWABLE ENERGY
Abstract
A multi-objective wind farm integration framework is proposed in this paper which considers the composite generation and reliability assessment and annualized operating and investment cost evaluation. An emission-controlled policy is adopted such that the amount of SOx and NOx decreases in line with renewable resource planning. Since the incorporation of large-scale distant wind farms is a problem of the multi-objective mixed-integer type with nonlinearities and non-convexities, this paper utilizes a fast elicit multi-objective Non-dominated Sorting Genetic Algorithm II (NSGA II) by probabilistic indices. It is noted that the impacts of the unavailability of the transmission system are modeled employing DC Optimal Power Flow (OPF) based on the incidence matrix together with the static security evaluation. Furthermore, in order to assess the performance of the suggested approach, the model is implemented on the Roy Billinton Test System (RBTS). Afterwards, distant wind farms integration into Iran's South-West Regional Grid (ISWRG) is studied. © 2019
2019
Autores
Pereira, R; Couto, M; Cunha, J; Melfe, G; Saraiva, J; Fernandes, JP;
Publicação
Composability, Comprehensibility and Correctness of Working Software - 8th Summer School, CEFP 2019, Budapest, Hungary, June 17-21, 2019, Revised Selected Papers
Abstract
2019
Autores
Negrini, F; Simo netto, ED; Rodrigues, GO; de Castro, HCGA;
Publicação
SISTEMAS & GESTAO
Abstract
Information and Communication Technologies (ICT) emerge as a strategic tool, indispensable for the survival of any organization. However, excessive use of ICT can lead to drawbacks such as equipment dependency, rapid obsolescence, and rising maintenance costs. Inefficient use of ICT can result in higher costs for organizations, which may cause them to lose important competitive advantages. In this context, outsourcing printing may be an alternative for institutions to reduce their costs and become more competitive. The aim of this paper is to evaluate scenarios about the financial viability of printing outsourcing in a Federal Higher Education Institution (Instituicoo Federal de Ensino Superior - IFES). To this end, an exploratory research was conducted, with a quantitative approach, using computational modeling, and using the System Dynamics methodology, with simulation and evaluation of three different scenarios: current scenario, likely scenario, unlikely scenario. The results obtained indicate that the unlikely scenario (100% of leased printers) resulted in lower printing costs over the period of the experiment, totaling R$ 637,828.00; the probable scenario (50% of leased printers) totaled R$ 1,000,480.00; while the current scenario (20% of leased printers) resulted in costs of R$ 1,603,060. With the simulations, it was found that printer leasing (outsourcing printing) is the best financial alternative for IFES, which served as a reference for the study, resulting in lower printing costs compared to printer acquisition. The use of systems modeling to evaluate scenarios has been used to support managers in the decision making involving ICT; however, there were no studies in the literature focused on the financial viability simulation of printer outsourcing. Thus, this work sought to bridge this gap by developing and validating a simulation model that can be applied in different scenarios and types of organizations, and work as a reference for future studies.
2019
Autores
Shultz, M; Le Bouquin, JB; Rivinius, T; Wade, GA; Kochukhov, O; Alecian, E; Petit, V; Pfuhl, O; Karl, M; Gao, F; Grellmann, R; Lin, CC; Garcia, P; Lacour, S;
Publicação
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Abstract
NU Ori is a massive spectroscopic and visual binary in the Orion Nebula Cluster, with four components: Aa, Ab, B, and C. The B0.5 primary (Aa) is one of the most massive B-type stars reported to host a magnetic field. We report the detection of a spectroscopic contribution from the C component in high-resolution ESPaDOnS spectra, which is also detected in a Very Large Telescope Interferometer data set. Radial velocity (RV) measurements of the inner binary (designated Aab) yield an orbital period of 14.3027(7) d. The orbit of the third component (designated C) was constrained using both RVs and interferometry. We find C to be on a mildly eccentric 476(1) d orbit. Thanks to spectral disentangling of mean line profiles obtained via least-squares deconvolution, we show that the Zeeman Stokes V signature is clearly associated with C, rather than Aa as previously assumed. The physical parameters of the stars were constrained using both orbital and evolutionary models, yielding M-Aa = 14.9 +/- 0.5 M-circle dot, M-Ab = 3.9 +/- 0.7 M-circle dot, and M-C = 7.8 +/- 0.7 M-circle dot. The rotational period obtained from longitudinal magnetic field (B-z) measurements is P-rot = 1.09468(7)d, consistent with previous results. Modelling of (B-z) indicates a surface dipole magnetic field strength of similar to 8 kG. NU Ori C has a magnetic field strength, rotational velocity, and luminosity similar to many other stars exhibiting magnetospheric Ha emission, and we find marginal evidence of emission at the expected level (similar to 1 per cent of the continuum).
2019
Autores
Catalao, JPS; Siano, P; Contreras, J; Chicco, G; Erdinc, O; Masoum, M; Aghaei, J; Wang, F; Li, FX; Bakirtzis, A; Parvania, M;
Publicação
IET RENEWABLE POWER GENERATION
Abstract
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