Torque Ripple Minimization in a Switched Reluctance Drive by Neuro-Fuzzy Compensation

Simple power electronic drive circuit and fault tolerance of converter are specific advantages of SRM drives, but excessive torque ripple has limited its use to special applications. It is well known that controlling the current shape adequately can minimize the torque ripple. This paper presents a new method for shaping the motor currents to minimize the torque ripple, using a neuro-fuzzy compensator. In the proposed method, a compensating signal is added to the output of a PI controller, in a current-regulated speed control loop. Numerical results are presented in this paper, with an analysis of the effects of changing the form of the membership function of the neuro-fuzzy compensator.Comment: To be published in IEEE Trans. on Magnetics, 200

Modelled testbeds: Visualizing and augmenting physical testbeds with virtual resources

Testbed facilities play a major role in the study and evolution of emerging technologies, such as those related to the Internet of Things. In this work we introduce the concept of modelled testbeds, which are 3D interactive representations of physical testbeds where the addition of virtual resources mimicking the physical ones is made possible thanks to back-end infrastructure. We present the architecture of the Syndesi testbed, deployed at the premises of University of Geneva, which was used for the prototype modelled testbed. We investigate several extrapolation techniques towards realistic value assignment for virtual sensor measurements. K-fold cross validation is performed in a dataset comprising of nearly 300’000 measurements of temperature, illuminance and humidity sensors collected from the physical sensors of the Syndesi testbed, in order to evaluate the accuracy of the methods. We obtain strong results including Mean Absolute Percentage Error (MAPE) levels below 7%

The design and evaluation of travelling gun irrigation systems: enrolador software

Technical Paperinfo:eu-repo/semantics/publishedVersio

Psychological aspects of pre-symptomatic testing for Machado–Joseph disease and familial amyloid polyneuropathy type I

Machado–Joseph disease [MJD, also spinocerebellar ataxia type 3 (SCA3)] and familial amyloid polyneuropathy type I (FAP-I or ATTR V30M) are neurodegenerative disorders, inherited in an autosomal dominant fashion, which have a high prevalence in Portugal, probably due to a founder effect. MJD and FAP-I are late-onset diseases, with symptoms emerging usually during adulthood. CGPP, which is the national reference centre for these disorders, has a genetic lab that offers diagnostic, pre-symptomatic and prenatal testing and an outpatient clinic to counsel and follow relatives at risk for hereditary ataxias, FAP- I and Huntington disease (HD). The present work is a review of our 10- year experience with psychological counselling of individuals at risk for MJD and FAP-I. Persons at risk for FAP-I may show a better response to pre-symptomatic testing than those who are at risk for MJD and HD because of the availability of liver transplantation, which may improve their health and life expectancy. Psychological well-being and specific distress of MJD and FAP-I test applicants, before undergoing genetic testing (baseline level) and 3 to 6 months after disclosure of test results, have shown a low level of change, both in identified carriers and non-carriers. A major goal of psychological characterization of at-risk individuals for MJD and FAP-I is to determine the factors that influence the uptake of genetic testing

Transpiration reduction as an answer to water stress: models versus measurements for irrigated olive trees in South Portugal

The so-called stress functions, allowing quantification of transpiration or evapotranspiration reduction, as an answer to water deficit stress (stress coefficient, Ks), are useful tools for irrigation scheduling. It is known that this coefficient depends on several variables and parameters, such as evapotranspiration rate, root patterns/density and soil properties. However, the most common Ks models with practical applicability do not include some of these factors and the experimental work on this matter is not abundant. A well-known model proposed in the FAO 56 manual uses two parameters: the allowable depletion (p) and the total available soil water (TAW) in the root zone, the input variable being the soil water depletion (SWD). We discuss the application of this model in olive trees under specific natural conditions. Two studies were conducted in Alentejo, South Portugal (2011 and 2017), in one intensive and one super intensive drip irrigated olive orchards (Olea europaea 'Arbequina'). Transpiration reduction was obtained from sap flow measurements. For both experiments, Ks was related to the estimated SWD. The experimental relationship was compared with modelling outputs. Experimental results show that, in both experiments, the Ks FAO 56 model only fits using parameters such as p= 0.05 and TAW = 350 mm. The suggested p in that manual is 0.7. Furthermore, for such soils, anisotropic canopy and small wetted area (drippers), 350 mm is much more than first approach estimates would suggest. The results can be related with the root system functioning and resilience of olive treesinfo:eu-repo/semantics/publishedVersio

Microclimate in coffee plantation grown under grevillea trees shading.

Microclima de café arborizado com grevílea. Medições de radiação solar global, velocidade do vento, temperatura e umidade relativa do ar, foram realizadas em um cafezal (Coffea arabica L.) cv. Icatu Vermelho IAC 4045, cultivado a pleno sol e arborizado com grevílea (Grevillea robusta), no município de Mococa ? SP (21º 28? S, 47º 01? W, altitude 665 m) entre janeiro e dezembro de 2005, com o objetivo de apresentar os efeitos do cultivo arborizado no microclima. Os resultados obtidos mostraram que houve atenuação média dos valores de radiação solar global, em cultivo de café arborizado, em 26%, com variação mensal de 24 a 30%. Pela descontinuidade da cobertura das árvores de grevílea, foi verificada diferença de transmissão da radiação solar em diferentes pontos do sistema arborizado. Foi verificada ainda redução média de 35% nas médias quinquidiais da velocidade do vento no cultivo arborizado em relação ao cultivo a pleno sol. O cultivo arborizado promoveu redução na temperatura máxima do ar e no déficit de saturação de vapor no período diurno, sendo essas reduções mais evidentes no ponto amostral próximo à árvore de grevílea

Eficiência da ureia revestida com polímeros, na produtividade de milho safrinha.

Em regiões tropicais e principalmente, sob cultivo em sistema de plantio direto, as perdas de N, na forma de NH3, por volatilização aliada à baixa disponibilidade hídrica, estão entre as principais causas de baixa produtividade de milho safrinha. Breda et al. (2010), constataram maior eficiência na utilização de ureia revestida com polímeros, em relação à redução das perdas de NH3 ocasionadas por volatilização. Consequentemente, ocasionando um melhor aproveitamento deste nutriente pelas plantas, podendo gerar incremento de produtividade. Em sistemas de plantio direto, onde há um maior acúmulo de resíduos vegetais na superfície do solo, as perdas de N, na forma de NH3, são maiores em relação a outros sistemas de cultivo, como por exemplo, o plantio convencional (VIERO, 2011). Contudo, o sistema plantio direto na palha, nos proporciona inúmeras vantagens em relação ao cultivo convencional, como por exemplo, menor suscetibilidade a erosão, controle de temperatura do solo, equilíbrio da micro e macro biota do solo, melhor conservação de água, dentre outras. Levando-nos a buscar alternativas eficientes para o seu manejo, principalmente na safrinha, onde estes benefícios são essenciais para o sucesso da lavoura. Diante do disposto acima, o objetivo deste estudo foi, avaliar o efeito da adubação nitrogenada protegida com polímeros, em plantas de milho cultivadas sob sistema de plantio direto, em regime de safrinha.Disponível em: http://www.cpao.embrapa.br/cds/milhosafrinha2013/PDF/61.pdf. Acesso em 18 dez. 2013

Intrinsic aerobic capacity sets a divide for aging and longevity

<p><b>Rationale:</b> Low aerobic exercise capacity is a powerful predictor of premature morbidity and mortality for healthy adults as well as those with cardiovascular disease. For aged populations, poor performance on treadmill or extended walking tests indicates closer proximity to future health declines. Together, these findings suggest a fundamental connection between aerobic capacity and longevity.</p> <p><b>Objectives:</b> Through artificial selective breeding, we developed an animal model system to prospectively test the association between aerobic exercise capacity and survivability (aerobic hypothesis).</p> <p><b>Methods and Results:</b> Laboratory rats of widely diverse genetic backgrounds (N:NIH stock) were selectively bred for low or high intrinsic (inborn) treadmill running capacity. Cohorts of male and female rats from generations 14, 15, and 17 of selection were followed for survivability and assessed for age-related declines in cardiovascular fitness including maximal oxygen uptake (VO<sub>2max</sub>), myocardial function, endurance performance, and change in body mass. Median lifespan for low exercise capacity rats was 28% to 45% shorter than high capacity rats (hazard ratio, 0.06; P<0.001). VO<sub>2max</sub>, measured across adulthood was a reliable predictor of lifespan (P<0.001). During progression from adult to old age, left ventricular myocardial and cardiomyocyte morphology, contractility, and intracellular Ca<sup>2+</sup> handling in both systole and diastole, as well as mean blood pressure, were more compromised in rats bred for low aerobic capacity. Physical activity levels, energy expenditure (Vo<sub>2</sub>), and lean body mass were all better sustained with age in rats bred for high aerobic capacity.</p> <p><b>Conclusions:</b> These data obtained from a contrasting heterogeneous model system provide strong evidence that genetic segregation for aerobic exercise capacity can be linked with longevity and are useful for deeper mechanistic exploration of aging.</p&gt