Observer-based tracking control for single machine infinite bus system via flatness theory

In this research, we aim to use the flatness control theory to develop a useful control scheme for a single machine connected to an infinite bus (SMIB) system taking into account input magnitude and rate saturation constraints. We adopt a fourth-order nonlinear SMIB model along an exciter and a turbine governor as actuators. According to the flatness-based control strategy, first we show that the adopted nominal SMIB model is a flat system. Then, we develop a full linearizing state feedback as well as an outer integral-type loop to ensure suitable tracking performances for the power and voltage as well as the angular velocity outputs. We assume that only the angular velocity of the generator is available to be measured. So, we provide a linear Luenberger observer to estimate the remaining states of the system. Also, the saturation nonlinearities are transferred to the linear part of the system and they are canceled out using their estimations. The efficiency and usefulness of the proposed observer-controller against faults are illustrated using simulation tests in Eurostag and Matlab. The results show that the clearing critical time of the introduced methodology is larger than the classical control approaches and the proposed observer-based flatness controller exhibits over much less control energy compared to the classic IEEE controllers

Power System Nonlinear Modal Analysis Using Computationally Reduced Normal Form Method

Increasing nonlinearity in today’s grid challenges the conventional small-signal (modal) analysis (SSA) tools. For instance, the interactions among modes, which are not captured by SSA, may play significant roles in a stressed power system. Consequently, alternative nonlinear modal analysis tools, notably Normal Form (NF) and Modal Series (MS) methods are being explored. However, they are computation-intensive due to numerous polynomial coefficients required. This paper proposes a fast NF technique for power system modal interaction investigation, which uses characteristics of system modes to carefully select relevant terms to be considered in the analysis. The Coefficients related to these terms are selectively computed and the resulting approximate model is computationally reduced compared to the one in which all the coefficients are computed. This leads to a very rapid nonlinear modal analysis of the power systems. The reduced model is used to study interactions of modes in a two-area power system where the tested scenarios give same results as the full model, with about 70% reduction in computation time

Nonadiabatic generation of spin currents in a quantum ring with Rashba and Dresselhaus spin-orbit interactions

When subjected to a linearly polarized terahertz pulse, a mesoscopic ring endowed with spin-orbit interaction (SOI) of the Rashba-Dresselhaus type exhibits nonuniform azimuthal charge and spin distributions. Both types of SOI couplings are considered linear in the electron momentum. Our results are obtained within a formalism based on the equation of motion satisfied by the density operator which is solved numerically for different values of the angle $\phi$, the angle determining the polarization direction of the laser pulse. Solutions thus obtained are later employed in determining the time-dependent charge and spin currents, whose values are calculated in the stationary limit. Both these currents exhibit an oscillatory behavior complicated in the case of the spin current by a beating pattern. We explain this occurrence on account of the two spin-orbit interactions which force the electron spin to oscillate between the two spin quantization axes corresponding to Rashba and Dresselhaus interactions. The oscillation frequencies are explained using the single particle spectrum.Comment: 9 pages, 5 figures, Conference "Advanced many-body and statistical methods in mesoscopic systems", June 27 -July 2, 2011, Constanta, Romani

Crecimiento tumoral agresivo coincidente con el uso de distracción osteogénica mandibular. Presentación de un caso

ResumenPropósitoComunicar un caso inusual de crecimiento tumoral agresivo en relación con el uso de distracción mandibular. La situación clínica presentada sugiere que los factores bioquímicos liberados durante la distracción ósea pueden interferir el desarrollo de los tumores malignos activos, provocando una rápida progresión.Material y métodosPresentamos el caso de una paciente con antecedentes de carcinoma basocelular esclerosante recurrente en el área labiomentoniana izquierda. A pesar de los múltiples intentos de extirpar completamente el tumor y el estrecho seguimiento realizado, 18 años después de realizar el diagnóstico inicial las biopsias tomadas mostraron infiltración tumoral de la mandíbula.Con el fin de minimizar la cantidad de hueso y partes blandas necesarias para la reconstrucción, se decidió realizar una distracción mandibular bilateral antes de realizar la resección mandibular, aprovechando así el crecimiento muy lento que tenía el tumor. Al cabo de 5 semanas de iniciar la distracción se objetivó una gran masa tumoral de nueva aparición al nivel del suelo de la boca anterior, que posteriormente se confirmó que tenía el mismo diagnóstico histopatológico que el tumor inicial.ResultadosDebido a la inesperada ocurrencia de la complicación presentada tuvimos que abandonar la distracción, y decidimos realizar una resección de espesor total del tercio facial inferior y la reconstrucción del defecto con un injerto libre vascularizado de peroné y un colgajo miocutáneo pectoral.ConclusiónLa distracción osteogénica puede complicar el curso de un proceso neoplásico local y su uso debe ser valorado como posible contraindicación en pacientes con procesos tumorales activos.AbstractPurposeto report an unusual case of aggressive tumoral growth related to the use of mandibular distraction. The clinical situation presented suggests that the biochemical factors released during the osseous distraction can interfere with the development of the active malignant tumors, triggering a rapid progression.Material and methodsWe present the case of a patient who had a history of recurrent sclerosing basal cell carcinoma in the left chin area. Despite of the multiples attempts to completely remove the tumor and the close follow- up conducted, 18 years from the initial diagnosis the biopsies taken showed tumoral infiltration of the mandibular bone.In order to take advantage of the slow rate of the tumoral growth, we decided to carry out a bilateral mandibular distraction before performing the mandibular resection and reduce in this manner the amount of the bone necessary for the reconstruction. Five weeks after the onset of the bone distraction a newly emerging tumoral mass could be observed in the anterior floor of the mouth, which was confirmed to have the same histological diagnose as the initial tumor.ResultsDue to the unexpected complication we had to abandon the distraction and decided to perform a full-thickness resection of the inferior third of the face and the reconstruction of the defect using a free vascularized fibular graft and a pectoralis major myocutaneous flap.ConclusionDistraction osteogenesis can complicate the course of a local neoplastic process and its use should be valued as a potential contraindication in patients with active tumors

Guz neuroendokrynny odbytnicy jako rzadka przyczyna wgłobienia odcinka odbytniczo-esiczego u dorosłych: opis przypadku i przegląd piśmiennictwa

Wgłobienie jelita jest często rozpoznawane u dzieci i młodzieży, natomiast u dorosłych występuje rzadko i nie daje charakterystycznych objawów. Niezależnie od lokalizacji u większości dorosłych wgłobienie jest następstwem obecności guza o różnej budowie histologicznej, wywodzącego się z błony wewnętrznej jelita. W niniejszej pracy przedstawiono przypadek wgłobienia odbytniczo-esiczego u dorosłego na podłożu guza neuroendokrynnego. Opisany przypadek jest wyjątkowy z następujących powodów: (1) guzy neuroendokrynne rzadko lokalizują się w esiczo-odbytniczym odcinku jelita, (2) obraz kliniczny wgłobienia odbytniczo-esiczego sprawia trudności diagnostyczne

Neuroendocrine rectal tumour as a rare aetiology of adult recto-sigmoidal intussusception: case presentation and literature review

Intestinal intussusception is a frequent paediatric pathology, but adult cases are rare and do not have a specific presentation. In most cases adult intestinal intussusception, regardless of its localisation, is caused by an endoluminal tumour, which can be of multiple pathological types. We report a sigmoido-rectal intussusception in an adult in whom an adenoneuroendocrine tumour was identified as the lead point. This case is unique for the following reasons: (1) neuroendocrine tumours rarely involve the sigmoido-rectal segment of the gut, (2) clinical presentation with a recto-sigmoidal intussusception presented a diagnostic challenge

New Challenges and Opportunities for Putting into Value the Diversity of the Danube Territorial Capital, as a “European Axis” in light of Bio-Resources Supply during 2030-2050, in the context of Global Demographic Projections for 2100

Diversity of the Danube territorial capital  is the part of World Heritage public investment - biodiversity, environmental protection, sustainable development, reducing poverty and increasing social inclusion, continued development of the global economic welfare, promote a healthy environment, conservation of bio-resources as a “European Axis” , business development in the context of eco-bio-economic, diplomatic instruments promoting eco-bio-economic development, food security, public health, are only several ideas of a smart modern world, which can be attached to development philosophy type “smart power” and contextual intelligence world for Sustainable Development Smart (Smart Sustainable Development) by Sustainable Diplomacy Smart (Smart Sustainable Diplomacy) in diversity of the Danube territorial capital, which can be a key ingredient of success for Excellence in Foreign Affairs Diplomatic and intelligence dedicated Environmental and Eco- Bio-Economy (SMART & Excellence in Environmental and Eco-Bio-Economic Affairs)

New Integrative, Cross-border and Transnational Approaches for a Carpatho-Danubiano-Pontic Transdisciplinary Mega Project Based on Horizon 2020 and the European Strategy for Bio-Economy 2030. Innovative Eco-bio-geo-economic Solutions and Legislative-Finan

This project is absolutely necessary because the economic situation, nationally and globally, requires innovative impetus that materialize in socio-economic development through the use of transalpine Eco-zone balanced and efficient management, responsible and rational local bio-resources, improving quality of life and therefore human and animal health, combating and preventing major environmental issues, sustainable use of biological resources for industrial purposes, while ensuring environmental protection and biodiversity, rational land use and not least food security. This project aims at increasing the added value of RDI national system - forming and research; - formation of new specialists; - conducting research into new areas of European institutions; - carrying out scientific research FOOD Bio-Platform in the context of innovative eco-bio-geo-economic solutions and legislative-financial synergies. The present project is contribute to counteract biodiversity loss, relying on the protection of natural heritage and cultural landscape vulnerable. Biodiversity in general and biodiversity protection in particular, must be compatible with economic development for the benefit of local communities, biodiversity as a “common heritage of mankind” and therefore, mankind must band together to preserve them. Overexploitation of resources to meet the demand for bio-products are in a continuous growth and industrial hazards can cause serious damage and endanger regional development. Changes in land use threatening cultural resources and landscapes and may lead to fragmentation of natural and ecological habitats.&nbsp

X-Y Pen Plotter Design Accomplished from Older Drives

The paper describes the design and the implementation of a small, easily operable and flexible 2-axis CNC pen plotter (Computer Numerical Control). It is accomplished from two old and available CD-ROM (Compact Disc Read-Only Memory) drives using their stepper motors and the main hardware structure. The two stepper motors move the pen platform along X and Y axis. The plotter has been tested for printing different images and texts. Thus, the functional and graphical requirements were demonstrated, the conclusion being that this device is efficient and precise, and it can be easily achieved from available components

Cervical Endometriosis – Case Report and Review of Literature

Endometriosis became a public health problem both due to the increasing number of affected patients and the severe quality of life impairment. Cervical endometriosis is defined as the presence of endometrial glands and stroma at cervical level. Primary and secondary cervical endometriosis are two separates entities that require distinct management. Symptomatic cases diagnosed with primary cervical endometriosis have indication for ERAD while patients with secondary cervical endometriosis should be referred to a specialized center because the surgical treatment may imply a high degree of difficulty. We present a 24-year-old woman with no history of cervical interventions, first diagnosed with cervical displasia and referred to our center for a second opinion. Secondary cervical endometriosis and vaginal endometriotic nodule were diagnosed. Following the general consensus for the benefits of surgery for endometriosis associated with pelvic pain, the patient was considered a candidate for laparoscopic surgery. Complete resection of the endometriotic tissue including the vaginal nodule with laparoscopic suture of the vaginal wall was realized. Laparoscopic surgery for endometriosis is proven to improve the patients’ quality of life, diminishing the symptoms and increases the likelihood of obtaining a spontaneous pregnancy. The presented case illustrates the benefits of surgery for secondary cervical endometriosis with marker improvement in quality of life proven with EHP-30 up to 2 years after surgery