Rotating 5D-Kaluza-Klein Space-Times from Invariant Transformations

Using invariant transformations of the five-dimensional Kaluza-Klein (KK) field equations, we find a series of formulae to derive axial symmetric stationary exact solutions of the KK theory starting from static ones. The procedure presented in this work allows to derive new exact solutions up to very simple integrations. Among other results, we find exact rotating solutions containing magnetic monopoles, dipoles, quadripoles, etc., coupled to scalar and to gravitational multipole fields.Comment: 24 pages, latex, no figures. To appear in Gen. Rel. Grav., 32, (2000), in pres

Measured Quantum Dynamics of a Trapped Ion

The measurement process is taken into account in the dynamics of trapped ions prepared in nonclassical motional states. The induced decoherence is shown to manifest itself both in the inhibition of the internal population dynamics and in a damping of the vibrational motion without classical counterpart. Quantitative comparison with present experimental capabilities is discussed, leading to a proposal for the verification of the predicted effects.Comment: 5 Pages, no figures; Plain REVTeX; to be published in the 1st May issue of Phys. Rev. A, Rap. Commun. (1997

Analysis of process variables via CFD to evaluate the performance of a FCC riser

Feedstock conversion and yield products are studied through a 3D model simulating the main reactor of the fluid catalytic cracking (FCC) process. Computational fluid dynamic (CFD) is used with Eulerian-Eulerian approach to predict the fluid catalytic cracking behavior. The model considers 12 lumps with catalyst deactivation by coke and poisoning by alkaline nitrides and polycyclic aromatic adsorption to estimate the kinetic behavior which, starting from a given feedstock, produces several cracking products. Different feedstock compositions are considered. The model is compared with sampling data at industrial operation conditions. The simulation model is able to represent accurately the products behavior for the different operating conditions considered. All the conditions considered were solved using a solver ANSYS CFX 14.0. The different operation process variables and hydrodynamic effects of the industrial riser of a fluid catalytic cracking (FCC) are evaluated. Predictions from the model are shown and comparison with experimental conversion and yields products are presented; recommendations are drawn to establish the conditions to obtain higher product yields in the industrial process

VirtualECare: group support in collaborative networks organizations for digital homecare

Collaborative Work plays an important role in today’s organizations and normally in areas where decisions must be made. However, any decision that involves a collective or group of decision makers is, by itself, complex but is becoming normal in recent years. In this work we present the VirtualECare project (Figure 10), intelligent multi‐agent system able to monitor, interact and serve its customers, which are, normally, in need of care services. In the last years there has been a substantially increase in the number of people needed of intensive care, especially among the elderly, a phenomenon that is related to population ageing. However, this is not exclusive of the elderly, as diseases as obesity, diabetes, and blood pressure have been increasing among young adults. As a new reality, it has to be dealt by the health sector, and particularly by the public one. Thus, the importance of finding new and cost effective ways for health care delivery are of particular importance, especially when one want them not to be removed from their “habitat”. Following this line of thinking, the VirtualECare project will be presented, like similar ones that preceded it. Recently we have assisted to a growing interest in combining the advances in information society ‐ computing, telecommunications and presentation – in order to create Group Decision Support Systems (GDSS). Indeed, the new economy, along with increased competition in today’s complex business environments, takes the companies to seek complementarities in order to increase competitiveness and reduce risks. Under these scenarios, planning takes a major role in a company life. However, effective planning depends on the generation and analysis of ideas (innovative or not) and, as a result, the idea generation and management processes are crucial. Our objective is to apply the above presented GDSS to a new area. We believe that the use of GDSS in the healthcare arena will allow professionals to achieve better results in the analysis of one’s Electronically Clinical Profile (ECP). This achievement is vital, regarding the explosion of knowledge and skills, together with the need to use limited resources and get better results

Brane-f(R)f(R) gravity and dark matter

The collision-free Boltzmann equation is used in the context of brane-$f(R)$ gravity to derive the virial theorem. It is shown that the virial mass is proportional to certain geometrical terms appearing in the Einstein field equations and contributes to gravitational energy and that such a geometric mass can be attributed to the virial mass discrepancy in a cluster of galaxies. In addition, the galaxy rotation curves are studied by utilizing the concept of conformal symmetry and notion of conformal Killing symmetry. The field equations may then be obtained in an exact parametric form in terms of the parameter representing the conformal factor. This provides the possibility of studying the behavior of the angular velocity of a test particle moving in a stable circular orbit. The tangential velocity can be derived as a function of the conformal factor and integration constants, resulting in a constant value at large radial distances. Relevant phenomenon such as the deflection of light passing through a region where the rotation curves are flat and the radar echo delay are also studied.Comment: 12 pages, 2 figures, to appear in PR

A simulation Approach to Assess Partners Selected for a Collaborative Network

[EN] Manufacturing enterprises are increasingly more aware of the importance of establishing collaborative relationships with their network partners, due to the advantages associated to collaboration. Nevertheless, the participation in a collaborative network (CN) comes with associated challenges, namely the need to reduce the potential for conflicts among partners. A CN consists of heterogeneous partners, each one defining its own objectives and activating its own strategies. In this context, the ability to quickly identify partners with aligned strategies is crucial for smooth operation of the CN. The main aim of this paper is to address the partners' selection problem in the context of Virtual organizations Breeding Environments (VBE) that facilitate and enable the creation of Virtual Organisations (VO), as one type of CN. In a first stage, the sets of enterprises, characterised by having the required competencies to create the VO, are identified among different potential candidates within the VBE. In a second stage, the strategies alignment approach, based on the system dynamics simulation method, is used for the partners' selection process, identifying the best set of enterprises. In this paper, the final stage of partners' selection process is addressed by obtaining the degree of alignment of the business strategies formulated by each set of enterprises. In the light of this, a system dynamics-simulation model, in AnyLogic, is presented to obtain the set of enterprises that have higher levels of alignment in its strategies. The proposed system dynamics-simulation model is applied to a case in the building industry, to deal with the partners' selection problem in a VBE with the aim of forming a stable and sustainable VO.This work has been funded in part by Programa Val i+d para investigadores en formación (ACIF 2012) and by the Uninova–Center of Technology and Systems and the Portuguese FCT-PEST program UID/EEA/00066/2013.Andres, B.; Poler, R.; Camarinha-Matos, L.; Afsarmanesh, H. (2017). A simulation Approach to Assess Partners Selected for a Collaborative Network. International Journal of Simulation Modelling. 16(3):399-411. https://doi.org/10.2507/IJSIMM16(3)3.382S39941116

Wormhole Cosmic Censorship

We analyze the properties of a Kerr-like wormhole supported by phantom matter, which is an exact solution of the Einstein-phantom field equations. It is shown that the solution has a naked ring singularity which is unreachable to null geodesics falling freely from the outside. Similarly to Roger Penrose's cosmic censorship, that states that all naked singularities in the Universe must be protected by event horizons, here we conjecture from our results that a naked singularity can also be fully protected by the intrinsic properties of a wormhole's throat

Decoherence and the quantum-classical limit in the presence of chaos

We investigate how decoherence affects the short-time separation between quantum and classical dynamics for classically chaotic systems, within the framework of a specific model. For a wide range of parameters, the distance between the corresponding phase-space distributions depends on a single parameter $\chi$ that relates an effective Planck constant $\hbar_{\rm eff}$, the Lyapunov coeffficient, and the diffusion constant. This distance peaks at a time that depends logarithmically on $\hbar_{\rm eff}$, in agreement with previous estimations of the separation time for Hamiltonian systems. However, for $\chi\lesssim 1$, the separation remains small, going down with $\hbar_{\rm eff}^2$, so the concept of separation time loses its meaning.Comment: 5 pages, 4 figures (in 6 postscript files) two of them are color figure