The asynchronous motor one-dimensional analysis

An application of the linear machine one-dimensional analysis method to the modeling of a conventional asynchronous induction motor, considered as a particular case of linear and sectorial machines, is described. A mathematical model for the calculation of the propulsive force developed by this motor, taking into account the transversal edge effect, is derived from the application of the one-dimensional theory and presented in this paper. As an application example, an induction motor is analyzed by means of the one-dimensional theory.

Effects of prenatal exposure to deltamethrin on forced swimming behavior, motor activity, and striatal dopamine levels in male and female rats

The effects of prenatal exposure of rat pups to 0.08 mg/kg deltamethrin (DTM) on physical, reflex and behavioral developmental parameters, on forced swimming and open-field behaviors, and on striatal monoamine levels at 60 days of age were observed. Maternal and offspring body weight, physical and reflex development were unaffected by the exposure to the pesticide. At 21 days of age, open-field locomotion frequency and immobility duration of male and female offspring were not different between control and exposed animals. However, male rearing frequency was increased in experimental animals. A decreased immobility latency to float and in general activity after the swimming test in male offspring was observed at adult age; no interference was detected in the float duration during the swimming test. In addition, these animals presented higher striatal 3,4-dihydroxyphenylacetic acid (DOPAC) levels without modification in dopamine (DA) levels and an increased DOPAC/DA ratio. These data indicate a higher activity of the dopaminergic system in these animals. Noradrenaline (NA) levels were increased, while MHPG levels were not detectable in the system studied. Serotonin (5-HT) and 5-hydroxyindolacetic acid (5-HIAA) levels, as well as the homovanillic acid (HVA)/DA ratio, were not modified by the exposure to the pesticide. No changes were observed in swimming and open-field behaviors nor were there any changes in striatal monoamines or their metabolites in the female experimental group. In relation to the pesticide formula, the present data showing that prenatal exposure to DTM alters latency to float and the activity of striatal dopaminergic system might reflect a persistent effect of the pesticide on animal motor activity, mainly in males. on the other hand, the decrease in general activity observed in experimental male rats suggests higher levels of emotionality induced by previous exposure to the swimming behavior test in relation to control animals. Data gathered in the present study may be important for the assessment of the safety of pyrethroid insecticides. (C) 2001 Elsevier B.V. All rights reserved.

Stepping-motor-driven constant-shear-rate rotating viscometer

Despite the frequent use of stepping motors in robotics, automation, and a variety of precision instruments, they can hardly be found in rotational viscometers. This paper proposes the use of a stepping motor to drive a conventional constant-shear-rate laboratory rotational viscometer to avoid the use of velocity sensor and gearbox and, thus, simplify the instrument design. To investigate this driving technique, a commercial rotating viscometer has been adapted to be driven by a bipolar stepping motor, which is controlled via a personal computer. Special circuitry has been added to microstep the stepping motor at selectable step sizes and to condition the torque signal. Tests have been carried out using the prototype to produce flow curves for two standard Newtonian fluids (920 and 12 560 mPa (.) s, both at 25 degrees C). The flow curves have been obtained by employing several distinct microstep sizes within the shear rate range of 50-500 s(-1). The results indicate the feasibility of the proposed driving technique.

Early Pancreas Transplant Improves Motor Nerve Conduction in Alloxan-Induced Diabetic Rats

The purpose of this study was to assess the temporal relationship between pancreas transplant and the development of electrophysiological changes in the sciatic and caudal nerves of alloxan-induced diabetic rats. Nerve conduction studies were performed in diabetic rats subjected to pancreas transplantation at 4, 12, and 24 weeks after diabetes onset, using nondiabetic and untreated diabetic rats as controls. Nerve conduction data were significantly altered in untreated diabetic control rats up to 48 weeks of follow-up in all time points. Rats subjected to pancreas transplantation up to 4 and 12 weeks after diabetes onset had significantly increased motor nerve conduction velocity with improvement of wave amplitude, distal latency, and temporal dispersion of compound muscle action potential in all follow-up periods (P<0.05); these parameters remained abnormal when pancreas transplantation were performed late at 24 weeks. Our results suggest that early pancreas transplant (at 4-12 weeks) may be effective in controlling diabetic neuropathy in this in vivo model.

Chest associated to motor physiotherapy acutely improves oxygen saturation, heart rate and respiratory rate in premature newborns with periventricular-intraventricular hemorrhage

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

Dynamic behavior of a linear induction motor

Although conventional rotating machines have been largely used to drive underground transportation systems, linear induction motors are also being considered for future applications owing to their indisputable advantages. A mathematical model for the transient behavior analysis of linear induction motors, when operating with constant r.m.s. currents, is presented in this paper. Operating conditions, like phase short-circuit and input frequency variations and also some design characteristics, such as air-gap and secondary resistivity variations, can be considered by means of this modeling. The basis of the mathematical modeling is presented. Experimental results obtained in the laboratory are compared with the corresponding simulations and discussed in this paper.

On Nonlinear Dynamics and Control of A Particular Portal Frame Foundation Model, Excited by a Non-Ideal Motor

The nonlinear dynamic response and a nonlinear control method of a particular portal frame foundation for an unbalanced rotating machine with limited power (non-ideal motor) are examined. Numerical simulations are performed for a set of control parameters (depending on the voltage of the motor) related to the static and dynamic characteristics of the motor. The interaction of the structure with the excitation source may lead to the occurrence of interesting phenomena during the forward passage through the several resonance states of the systems. A mathematical model having two degrees of freedom simplifies the non-ideal system. The study of controlling steady-state vibrations of the non-ideal system is based on the saturation phenomenon due to internal resonance.

Comparação entre o desempenho motor de hommes e mulheres em séries múltiplas de exercícios com pesos

The magnitude of men and women's neuromuscular, metabolic, and morphologic responses seems to be quite different even when both are submitted to exercise protocols using similar weight exercises protocols. However, differences in the motor performance between men and women have been predominantly reported in protocols based on isometric and isokinetic contractions. Thus, this study aimed to analyze men and women's behavior during multiple sets of weight exercises achieving the exhaustion, and later verifying possible differences as to the physical performance between genders using weights with similar intensity. For this, 83 subjects (50 men, and 33 women), 48 hours after being submitted to 1-RM tests in bench press, squat and arm curl performed a protocol composed by four sets at 1-RM 80% up to achieving the exhaustion in each of three exercises to evaluate the endurance ability to the fatigue in different muscular groups. It was used the ANOVA and ANCOVA for repeated measurements, followed by the Tukey's post hoc test, where P < 0.05 to the data treatment. It was verified a significant fall in the performance both in men and in women since the first up to the fourth sets of every exercise investigated (P < 0.01). Although the fatigue magnitude was higher in men in all the three exercises, the effect on the gender was only identified in the arm curl exercise (P < 0.01). The results of this study indicated that men and women presented quite different behavior in multiple sets of weight exercises, and women presented a more stable performance and a higher endurance ability to the fatigue in the arm curl as well.

Recurrent neural network for induction motor speed estimation in industry applications

Many electronic drivers for the induction motor control are based on sensorless technologies. The proposal of this work Is to present an alternative approach of speed estimation, from transient to steady state, using artificial neural networks. The inputs of the network are the RMS voltage, current and speed estimated of the induction motor feedback to the input with a delay of n samples. Simulation results are also presented to validate the proposed approach. © 2006 IEEE.

Effects of motor intervention in elderly patients with dementia: An analysis of randomized controlled trials

The objective of this study was to analyze randomized controlled trials published in the last decades involving motor intervention as a treatment for dementia, based on Physiotherapy Evidence Database (PEDro) criteria. A database search was performed using the following keywords: randomized controlled trial, dementia, physiotherapy, physical therapy, occupational therapy, physical education, motor approach, exercise, and physical activity. Ten trials were found: 4 related to physiotherapy, 3 to occupational therapy, 1 to physical education, and 2 to interdisciplinary motor intervention. The efficacy of motor intervention was confirmed in the following variables: psychosocial function, physical health and function, affective status, and caregiver's distress (P < .05). Results related to mobility were not significant (P > .05). Behavior, cognitive performance, activities of daily living, and risk of falls were not similar among the articles. From a total score of 10 points, with excellence characterized as the highest punctuation, the articles were classified between 3 and 7 by PEDro. Motor intervention was shown to be an alternative for minimizing physical and mental decline. PEDro has been confirmed as a very reliable tool to analyze studies and as an evaluation criteria, both qualitative and quantitative, allowing the establishment of motor intervention strategies for the treatment of patients with dementia. © 2007 Lippincott Williams & Wilkins, Inc.

Síntomas depresivos y trastorno motor en pacientes con enfermedad de Parkinson

Introduction. Complex relations between brain and psychopathology have attracted the interest of researchers, aiming to clarify the neurobiological mechanisms of depression in Parkinson's disease, obviously in addiction to mental features. Aims. The association of motor impairment and decline of personal autonomy with severity of depressive symptoms was the hypothesis of the present study. Aiming to check this hypothesis, the objective of this study consisted in investigating relationships between the severity of depressive symptoms and motor characteristics of Parkinson's disease. Patients and methods. Thirty patients (53 to 80 year-old) with medical diagnosis of idiopathic Parkinson's disease in initial clinic stages were studied. The Unified Parkinson's Disease Rating Scale, Hoehn-Yahr Scale, and Schwab & England Scale were used to assess the clinic signs and symptoms. The depressive symptoms were identified by complete anamnesis, examination of mental condition, and the Hamilton Rating Scale for Depression and the Anxiety and Depression Scale. Statistical analysis was performed by Pearson's correlation and multiple regression analysis. Results. A significant correlation of severity of depression symptoms with disease stage (p < 0.02), with motor signs (p < 0.008), and with functional performance (p < 0.007) was found. Conclusion. There was significant association between motor impairment and severity of depressive symptoms, and between depression and early disease onset or prolonged duration of Parkinson's disease. © 2007, Revista de Neurología.

A simplified method for determining the high frequency induction motor equivalent electrical circuit parameters to be used in EMI effect

The aim of this paper is to present a simple method for determining the high frequency parameters of a three-phase induction motor to be used in studies involving variable speed drives with PWM three-phase inverters, in which it is necessary to check the effects caused to the motor by the electromagnetic interference, (EMI) in the differential mode, as well as in the common mode. The motor parameters determination is generally performed in adequate laboratories using accurate instruments, such as very expensive RLC bridges. The method proposed here consists in the identification of the motor equivalent electrical circuit parameters in rated frequency and in high frequency through characteristic tests in the laboratory, together with the use of characteristic equations and curves, shown in the references to be mentioned for determining the motor high frequency parasite capacitances and also through system simulations using dedicated software, like Pspice, determining the characteristic waveforms involved in the differential and common mode phenomena, comparing and validating the procedure through published papers [01].