Active vibration control using delayed resonant feedback

Delayed feedback (DF) control is a well-established technique to suppress single frequency vibration of a non-minimum phase system. Modal control is also a well-established technique to control multiple vibration modes of a minimum phase system. In this paper these techniques are combined to simultaneously suppress multiple vibration modes of a non-minimum phase system involving a small time delay. The control approach is called delayed resonant feedback (DRF) where each modal controller consists of a modal filter to extract the target mode signal from the vibration response, and a phase compensator to account for the phase delay of the mode. The methodology is first discussed using a single mode system. A multi-mode system is then studied and experimental results are presented to demonstrate the efficacy of the control approach for two modes of a beam. It is shown that the system behaves as if each mode under control has a dynamic vibration absorber attached to it, even though the actuator and the sensor are not collocated and there is a time delay in the control system. © 2013 IOP Publishing Ltd.

Port state control in the Caribbean

This edition of the FAL Bulletin describes and analyses the control of ships at ports - the so-called "Port State Control" - in the Caribbean. It is based on a text supplied by Mr. Curtis A. Roach, Regional Maritime Safety Advisor, CARICOM.

Impact of insecticide resistance on the field control of Aedes aegypti in the State of São Paulo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mitochondrial DNA control region diversity in a population from Espirito Santo state, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Outbreak control and clinical, pathological, and epidemiological aspects and molecular characterization of a bovine herpesvirus type 5 on a feedlot farm in S(a)over-tildeo Paulo State

This paper describes the control, epidemiological, pathological, and molecular aspects of an outbreak of meningoencephalitis in calves due to bovine herpesvirus 5 at a feedlot with 540 animals in Sa (a) over tildeo Paulo State, Brazil. The introduction of new animals and contact between the resident animals and the introduced ones were most likely responsible for virus transmission. Bovine herpesvirus 1 vaccine was used, resulting in the efficacy of the outbreak control, although two bovine herpesvirus 1 positive animals, vaccinated and revaccinated, presented meningoencephalitis, thereby characterizing vaccinal failure.

BIRD CONTROL UNDER A STATE FISH AND GAME PERMIT SYSTEM

I guess the impetus for laws in our state, really was the action of the city of Boston in 1963, when the Parks and Recreation Department felt that it was time to do something about massive populations of pigeons on the Boston Commons and in the city. The Parks Department came to our agency to find out what could be done. We immediately found as a result of a reorganization and recodification of the laws some 20 years before, that it was illegal to use or apply poisons for the purpose of killing any birds or mammals in the Commonwealth of Massachusetts. Property owners were given the privilege to destroy animals that were doing damage to their property, but only through mechanical means, certainly not by the use of toxicants. We helped the city of Boston draft a bill in 1963, which allowed our agency, the Division of Fisheries and Game, the agency responsible for all wildlife species in the state, the opportunity to issue certain permits for the use of poison, giving full authority to the director of Fisheries and Game with, of course, approval of my board. This allowed certain discretion on our part.

Factors associated with preterm birth in Campina Grande, Paraiba State, Brazil: a case-control study

A case-control study (2008-2009) analyzed risk factors for preterm birth in the city of Campina Grande, Paraiba State, Brazil. A total of 341 preterm births and 424 controls were included. A multiple logistic regression model was used. Risk factors for preterm birth were: previous history of preterm birth (OR = 2.32; 95% CI: 1.25-4.29), maternal age (OR = 2.00; 95% CI: 1.00-4.03), inadequate prenatal care (OR = 2.15; 95% CI: 1.40-3.27), inadequate maternal weight gain (OR = 2.33; 95% CI: 1.45-3.75), maternal physical injury (OR = 2.10; 95% CI: 1.22-3.60), hypertension with eclampsia (OR = 17.08; 95% CI: 3.67-79.43) and without eclampsia (OR = 6.42; 95% CI: 3.50-11.76), hospitalization (OR = 5.64; 95% CI: 3.47-9.15), altered amniotic fluid volume (OR = 2.28; 95% CI: 1.32-3.95), vaginal bleeding (OR = 1.54; 95% CI: 1.01-2.34), and multiple gestation (OR = 22.65; 95% CI: 6.22-82.46). High and homogeneous prevalence of poverty and low maternal schooling among both cases and controls may have contributed to the fact that socioeconomic variables did not remain significantly associated with preterm birth.

CASE-CONTROL STUDY OF AN OUTBREAK OF ACUTE TOXOPLASMOSIS IN AN INDUSTRIAL PLANT IN THE STATE OF SÃO PAULO, BRAZIL

Foodborne diseases represent operational risks in industrial restaurants. We described an outbreak of nine clustered cases of acute illness resembling acute toxoplasmosis in an industrial plant with 2300 employees. These patients and another 36 similar asymptomatic employees were diagnosed with anti-T. gondii IgG titer and avidity by ELISA. We excluded 14 patients based on high IgG avidity and chronic toxoplasmosis: 13 from controls and one from acute disease other than T. gondii infection. We also identified another three asymptomatic employees with T.gondii acute infection and also anti-T. gondii IgM positive as remaining acute cases. Case control study was conducted by interview in 11 acute infections and 20 negative controls. The ingestion of green vegetables, but not meat or water, was observed to be associated with the incidence of acute disease. These data reinforce the importance of sanitation control in industrial restaurants and also demonstrate the need for improvement in quality control regarding vegetables at risk for T. gondii oocyst contamination. We emphasized the accurate diagnosis of indexed cases and the detection of asymptomatic infections to determine the extent of the toxoplasmosis outbreak.

Case-control study of an outbreak of acute toxoplasmosis in an industrial plant in the state of São Paulo, Brazil

Foodborne diseases represent operational risks in industrial restaurants. We described an outbreak of nine clustered cases of acute illness resembling acute toxoplasmosis in an industrial plant with 2300 employees. These patients and another 36 similar asymptomatic employees were diagnosed with anti-T. gondii IgG titer and avidity by ELISA. We excluded 14 patients based on high IgG avidity and chronic toxoplasmosis: 13 from controls and one from acute disease other than T. gondii infection. We also identified another three asymptomatic employees with T.gondii acute infection and also anti-T. gondii IgM positive as remaining acute cases. Case control study was conducted by interview in 11 acute infections and 20 negative controls. The ingestion of green vegetables, but not meat or water, was observed to be associated with the incidence of acute disease. These data reinforce the importance of sanitation control in industrial restaurants and also demonstrate the need for improvement in quality control regarding vegetables at risk for T. gondii oocyst contamination. We emphasized the accurate diagnosis of indexed cases and the detection of asymptomatic infections to determine the extent of the toxoplasmosis outbreak.

Nonlinear constrained and saturated control of power electronics and electromechanical systems

Power electronic converters are extensively adopted for the solution of timely issues, such as power quality improvement in industrial plants, energy management in hybrid electrical systems, and control of electrical generators for renewables. Beside nonlinearity, this systems are typically characterized by hard constraints on the control inputs, and sometimes the state variables. In this respect, control laws able to handle input saturation are crucial to formally characterize the systems stability and performance properties. From a practical viewpoint, a proper saturation management allows to extend the systems transient and steady-state operating ranges, improving their reliability and availability. The main topic of this thesis concern saturated control methodologies, based on modern approaches, applied to power electronics and electromechanical systems. The pursued objective is to provide formal results under any saturation scenario, overcoming the drawbacks of the classic solution commonly applied to cope with saturation of power converters, and enhancing performance. For this purpose two main approaches are exploited and extended to deal with power electronic applications: modern anti-windup strategies, providing formal results and systematic design rules for the anti-windup compensator, devoted to handle control saturation, and “one step” saturated feedback design techniques, relying on a suitable characterization of the saturation nonlinearity and less conservative extensions of standard absolute stability theory results. The first part of the thesis is devoted to present and develop a novel general anti-windup scheme, which is then specifically applied to a class of power converters adopted for power quality enhancement in industrial plants. In the second part a polytopic differential inclusion representation of saturation nonlinearity is presented and extended to deal with a class of multiple input power converters, used to manage hybrid electrical energy sources. The third part regards adaptive observers design for robust estimation of the parameters required for high performance control of power systems.

STATE OF CHARGE BASED DROOP SURFACE FOR OPTIMAL CONTROL OF DC MICROGRIDS

For a microgrid with a high penetration level of renewable energy, energy storage use becomes more integral to the system performance due to the stochastic nature of most renewable energy sources. This thesis examines the use of droop control of an energy storage source in dc microgrids in order to optimize a global cost function. The approach involves using a multidimensional surface to determine the optimal droop parameters based on load and state of charge. The optimal surface is determined using knowledge of the system architecture and can be implemented with fully decentralized source controllers. The optimal surface control of the system is presented. Derivations of a cost function along with the implementation of the optimal control are included. Results were verified using a hardware-in-the-loop system.

Self-control strength in the relation between trait test anxiety and state anxiety

The present research examined whether in a test situation, the relation between trait test anxiety and state anxiety depends on the momentary availability of self-control strength. Since self-control strength is crucial for emotion regulation, we assume that trait test anxiety is more closely related to state anxiety if self-control strength is depleted than if it is not depleted. We conducted an experiment with 119 undergraduates in which we measured trait test anxiety, manipulated availability of self-control strength, and assessed state anxiety after a test announcement. Consistent with the assumption, multiple regression analyses revealed that trait test anxiety and state anxiety were positively related if self-control strength was depleted, but were not related if self-control strength was intact.

The role of self-control strength in the development of state anxiety in test situations

Self-control strength may affect state anxiety because emotion regulation is impaired in individuals whose self-control strength has been temporarily depleted. Increases in state anxiety were expected to be larger for participants with depleted compared to nondepleted self-control strength, and trait test anxiety should predict increases in state anxiety more strongly if self-control strength is depleted. In a sample of 76 university students, trait test anxiety was assessed, self-control strength experimentally manipulated, and state anxiety measured before and after the announcement of a test. State anxiety increased after the announcement. Trait test anxiety predicted increases in state anxiety only in students with depleted self-control strength, suggesting that increased self-control strength may be useful for coping with anxiety.