Proposta de Controle Automático e Monitoramento Operacional do Bombeio Centrífugo Submerso em Sistemas de Produção Offshore

A automação dos métodos de elevação artificial tem grande potencial para aumentar a eficiência da operação dos poços de petróleo. Neste contexto, este trabalho apresenta uma proposta de controle automático e monitoramento operacional aplicada ao Bombeio Centrifugo Submerso em um Módulo de Bombeio, que é parte integrante de um sistema de produção Offshore. A proposta envolve a implementação de controladores PID, em uma estrutura comutada, composta por malhas de controle do diferencial de pressão fornecido pela bomba e da pressão de admissão, e de uma camada de monitoramento do desempenho do sistema de controle. Os controladores têm como objetivo a) controlar o ponto de operação da BCS e, b) evitar a ocorrência de instabilidades operacionais provocadas pelas altas frações de gás livre (FGL) em sua admissão. Este trabalho envolveu três etapas principais: 1) projeto e implementação dos controladores PID em simulador transiente unidimensional de escoamento de fluidos (OLGA) a partir do modelo de um poço marítimo; 2) simulação de dados associados a ocorrência de falhas no processo em malha fechada, relacionadas a mudanças nas condições dos equipamentos submarinos e nas propriedades dos fluidos, de reservatório e da planta; e 3) tratamento e análise dos dados em Matlab a partir da aplicação de técnicas de detecção e diagnóstico de falhas baseadas em análise de componentes principais (PCA) e estatísticas T2 e Q (Hottelings). Os resultados mostram que a aplicação da teoria de controle clássico contribui para a automação do método BCS ao promover o controle do ponto de operação da bomba em eventos de aceleração/desaceleração e o funcionamento ininterrupto do sistema de elevação em condições que levariam a altas FGL na bomba. Adicionalmente, a camada de monitoramento é fundamental para detectar e diagnosticar falhas no processo, indicando ao operador as situações que demandam sintonia dos controladores e ajuste de setpoints de modo a manter o desempenho para o qual foram projetados. Palavras-chave: Bombeio Centrifugo Submerso. Módulo de Bombeio. Controle Automático. Monitoramento de Processos. Detecção de Falhas. Diagnóstico de Falhas

X-ray Absorption Linear Dichroism at the Ti K-edge of TiO2 anatase single crystal

Anatase TiO2 (a-TiO2) exhibits a strong X-ray absorption linear dichroism with the X-ray incidence angle in the pre-edge, the XANES and the EXAFS at the titanium K-edge. In the pre-edge region the behaviour of the A1-A3 and B peaks, originating from the 1s-3d transitions, is due to the strong $p$-orbital polarization and strong $p-d$ orbital mixing. An unambiguous assignment of the pre-edge peak transitions is made in the monoelectronic approximation with the support of ab initio finite difference method calculations and spherical tensor analysis in quantitative agreement with the experiment. It is found that A1 is mostly an on-site 3d-4p hybridized transition, while peaks A3 and B are non-local transitions, with A3 being mostly dipolar and influence by the 3d-4p intersite hybridization, while B is due to interactions at longer range. Finally, peak A2 which was previously assigned to a transition involving pentacoordinated titanium atoms exhibits a quadrupolar angular evolution with incidence angle. These results pave the way to the use of the pre-edge peaks at the K-edge of a-TiO2 to characterize the electronic structure of related materials and in the field of ultrafast XAS where the linear dichroism can be used to compare the photophysics along different axes.Comment: 43 pages, 19 figure

Bacillary Angiomatosis by Bartonella Quintana in an HIV-Infected Patient

Bacillary angiomatosis and bacillary peliosis are opportunistic infections caused by Bartonella henselae and Bartonella quintana, which occur in patients with late-stage infection. We report a case of bacillary angiomatosis in an HIV-infected patient with skin, bone, and probably liver involvement, The identification of the agent (B quintana ) was done by polymerase chain reaction in the skin specimen. The patient had complete regression of all lesions after a 6-month regimen of oral erythromycin

HISTÓRIA DA ELETRORRETINOGRAFIA

The eye and its diseases have been studied since the time of the ancient Egypt; therefore, ophthalmology is recognized as one of the first medical specialties to ever exist. Along the years many advances in this area occurred, as the invention of the ophthalmoscope during the 19th Century and other ancillary methods in the 20th Century. After the invention of the ophthalmoscope, the observation and study of the retina, the anatomic part of the eye that transforms light energy into electric energy (phototransduction) stimulating the brain to form an image. Electroretinography is an ophthalmic examination that captures this electrical response generated by cells of the retina when stimulated by light. This is an excellent tool for studying the function of the retina, yet it is still a modestly widespread practice in the Brazilian veterinary medicine scenario. This paper aims to review the history of this valuable method of diagnosis.O olho juntamente com suas doenças vem sendo estudado desde o Egito antigo, sendo a oftalmologia, portanto, considerada como uma das primeiras especialidades médicas a existir. Com a invenção do oftalmoscópio no século XIX bem como de outros métodos de exames diagnósticos no século XX, iniciou-se a observação e o estudo da retina, tecido nervoso que realiza fototransdução e faz a passagem do estímulo elétrico para o cérebro, formando a imagem. A eletrorretinografia é um capítulo peculiar na história da oftalmologia. Trata-se de um exame oftálmico funcional que capta a resposta elétrica produzida pelas células da retina quando estimuladas. Tornou-se uma excelente ferramenta para estudar a funcionalidade da retina de animais e seres humanos, porém seu uso ainda encontra-se pouco difundido na Medicina Veterinária brasileira. O trabalho presente tem o objetivo de revisar a história deste valioso método de diagnóstico

Coupled motion of Xe clusters and quantum vortices in He nanodroplets

Citation: Jones, C. F., Bernando, C., Tanyag, R. M. P., Bacellar, C., Ferguson, K. R., Gomez, L. F., . . . Vilesov, A. F. (2016). Coupled motion of Xe clusters and quantum vortices in He nanodroplets. Physical Review B - Condensed Matter and Materials Physics, 93(18). doi:10.1103/PhysRevB.93.180510Additional Authors: Erk, B.;Foucar, L.;Hartmann, R.;Neumark, D. M.;Epp, S. W.;Englert, L.;Siefermann, K. R.;Weise, F.;Rudek, B.;Sturm, F. P.;Ullrich, J.;Bostedt, C.;Gessner, O.;Vilesov, A. F.Single He nanodroplets doped with Xe atoms are studied via ultrafast coherent x-ray diffraction imaging. The diffraction images show that rotating He nanodroplets about 200 nm in diameter contain a small number of symmetrically arranged quantum vortices decorated with Xe clusters. Unexpected large distances of the vortices from the droplet center (?0.7-0.8 droplet radii) are explained by a significant contribution of the Xe dopants to the total angular momentum of the droplets and a stabilization of widely spaced vortex configurations by the trapped Xe clusters. © 2016 American Physical Society

Femtosecond X-ray emission study of the spin cross-over dynamics in haem proteins

In haemoglobin (consisting of four globular myoglobin-like subunits), the change from the low-spin (LS) hexacoordinated haem to the high spin (HS) pentacoordinated domed form upon ligand detachment and the reverse process upon ligand binding, represent the transition states that ultimately drive the respiratory function. Visible-ultraviolet light has long been used to mimic the ligand release from the haem by photodissociation, while its recombination was monitored using time-resolved infrared to ultraviolet spectroscopic tools. However, these are neither element- nor spin-sensitive. Here we investigate the transition state in the case of Myoglobin-NO (MbNO) using femtosecond Fe Kalpha and Kbeta non-resonant X-ray emission spectroscopy (XES) at an X-ray free-electron laser upon photolysis of the Fe-NO bond. We find that the photoinduced change from the LS (S = 1/2) MbNO to the HS (S = 2) deoxy-myoglobin (deoxyMb) haem occurs in ca. 800 fs, and that it proceeds via an intermediate (S = 1) spin state. The XES observables also show that upon NO recombination to deoxyMb, the return to the planar MbNO ground state is an electronic relaxation from HS to LS taking place in ca. 30 ps. Thus, the entire ligand dissociation-recombination cycle in MbNO is a spin cross-over followed by a reverse spin cross-over process

Atomic-Level Description of Thermal Fluctuations in Inorganic Lead Halide Perovskites

A comprehensive microscopic description of thermally induced distortions in lead halide perovskites is crucial for their realistic applications, yet still unclear. Here, we quantify the effects of thermal activation in CsPbBr3 nanocrystals across length scales with atomic-level precision, and we provide a framework for the description of phase transitions therein, beyond the simplistic picture of unit-cell symmetry increase upon heating. The temperature increase significantly enhances the short-range structural distortions of the lead halide framework as a consequence of the phonon anharmonicity, which causes the excess free energy surface to change as a function of temperature. As a result, phase transitions can be rationalized via the soft-mode model, which also describes displacive thermal phase transitions in oxide perovskites. Our findings allow to reconcile temperature-dependent modifications of physical properties, such as changes in the optical band gap, that are incompatible with the perovskite time- and space-average structures

Carbon K-edge x-ray emission spectroscopy of gas phase ethylenic molecules

We report on the C K-edge x-ray absorption spectra and the resonant (RXES) and non-resonant (NXES) x-ray emission spectra of ethylene, allene and butadiene in the gas phase. The RXES and NXES show clear differences for the different molecules. Overall both types of spectra are more structured for ethylene and allene, than for butadiene. Using density functional theory–restricted open shell configuration interaction single calculations, we simulate the spectra with remarkable agreement with the experiment. We identify the spectral features as being due to transitions involving localised 1s orbitals. For allene, there are distinct spectral bands that reflect transitions predominantly from either the central or terminal carbon atoms. These results are discussed in the context of ultrafast x-ray studies aimed at detecting the passage through conical intersections in polyatomic molecules

Communication: X-ray coherent diffractive imaging by immersion in nanodroplets

Citation: Tanyag, R. M. P., Bernando, C., Jones, C. F., Bacellar, C., Ferguson, K. R., Anielski, D., . . . Vilesov, A. F. (2015). Communication: X-ray coherent diffractive imaging by immersion in nanodroplets. Structural Dynamics, 2(5), 9. doi:10.1063/1.4933297Lensless x-ray microscopy requires the recovery of the phase of the radiation scattered from a specimen. Here, we demonstrate a de novo phase retrieval technique by encapsulating an object in a superfluid helium nanodroplet, which provides both a physical support and an approximate scattering phase for the iterative image reconstruction. The technique is robust, fast-converging, and yields the complex density of the immersed object. Images of xenon clusters embedded in superfluid helium droplets reveal transient configurations of quantum vortices in this fragile system. (C) 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.Additional Authors: Neumark, D. M.;Rolles, D.;Rudek, B.;Rudenko, A.;Siefermann, K. R.;Ullrich, J.;Weise, F.;Bostedt, C.;Gessner, O.;Vilesov, A. F

Tecnologias e métodos que auxiliam na comunicação de surdocegos: uma revisão bibliográfica

Este artigo descreve a primeira análise de uma pesquisa bibliográfica que explora as abordagens dos trabalhos realizados na temática de deficiências múltiplas focado em pessoas com surdocegueira. Com a finalidade de identificar as tecnologias, as linguagens e os tipos de dispositivos utilizados na comunicação dos surdocegos e, que de alguma forma, auxiliem a sua educação. Como resultado inicial, identificou-se como principal linguagem para estabelecer a comunicação, o braile e suas derivações: bodybraile, fingerbraile, e uma predominância de recursos para a comunicação bidirecional na interação de indivíduos surdocegos. Foram poucos trabalhos que exploraram métodos ou recursos para aprendizagem