3 research outputs found
Predictive Stator Flux and Load Angle Control of Synchronous Reluctance Motor Drives Operating in a Wide Speed Range
This paper presents a new simplified finitecontrol-
set model predictive control strategy for synchronous
reluctance motors operating in the entire speed
range. It is a predictive control scheme that regulates the
stator flux and the load angle of the synchronous reluctance
motor, incorporating the ability to operate the drive in the
field-weakening region and respecting the motor voltage
and current limits as well as the load angle limitation
needed to operate this type of motor in the maximum
torque per voltage region. The proposed control strategy
possesses some attractive features, such as no need for
controller calibration, no weighting factors in the cost function,
good robustness against parameter mismatch, and
smaller computational cost compared to more traditional
finite-control-set model predictive control algorithms.
Simulation and experimental results obtained using a
high-efficiency synchronous reluctance motor demonstrate
the effectiveness of the proposed control scheme.info:eu-repo/semantics/publishedVersio
Molecular detection of Aggregatibacter actinomycetemcomitans on metallic brackets by the checkerboard DNA-DNA hybridization technique
Introduction: The purpose of this randomized clinical study was to evaluate the presence of the periodontal pathogen Aggregatibacter actinomycetemcomitans on metallic brackets and the effectiveness of a 0.12% chlorhexidine digluconate mouthwash in inhibiting this microorganism. Methods: The study involved 35 patients of both sexes having orthodontic treatment with fixed appliances between the ages of 14 and 22 years, randomized into 2 groups: experimental (n = 17) and control (n = 18). Two new metallic brackets were placed on the patients' premolars, and the subjects rinsed with a solution of 0.12% chlorhexidine digluconate or a placebo solution twice a week for 30 days. After that, the brackets were removed and underwent microbiologic analysis with the checkerboard DNA-DNA hybridization technique. Data were analyzed by using the Student t, Fisher exact, and Mann-Whitney tests at the significance level of 5%. Results: The results showed that A actinomycetemcomitans was present in all brackets from the subjects in the control group vs 83% of the subjects who rinsed with chlorhexidine digluconate (P<0.0001). There were also significantly lower levels of this species in the chlorhexidine digluconate group compared with the control group (P = 0.0003). Conclusions: We concluded that 0.12% chlorhexidine digluconate rinsing, twice a week for 30 days during orthodontic treatment, is effective in reducing the presence and levels of A actinomycetemcomitans on metallic brackets. (Am J Orthod Dentofacial Orthop 2012;142:481-6)National Council for Scientific and Technological Development (CNPq) [481894/2007-1, 304793/2007-8]National Council for Scientific and Technological Development (CNPq
Use of the checkerboard DNA-DNA hybridisation technique for in vivo detection of cariogenic microorganisms on metallic brackets, with or without use of an antimicrobial agent
Objective: Using checkerboard DNA-DNA hybridisation (CDDH) assay, this randomised clinical study evaluated the contamination of metallic brackets by four cariogenic bacterial strains (Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei and Lactobacillus acidophilus) and the efficacy of 0.12% chlorhexidine gluconate (CHX) mouthwashes in reducing bacterial contamination. Methods: Thirty-nine 11-33-year-old patients under treatment with fixed orthodontic appliances were enrolled in the study and had 2 new metallic brackets bonded to premolars. Nineteen patients used a 0.12% CHX mouthwash (Periogard (R)) and 20 patients used a placebo mouthwash (control) twice a week. After 30 days, the brackets were removed and samples were obtained for analysis by CDDH. Data were analysed statistically by the Kruskal-Wallis test (alpha = 0.05) using the SAS software. Results: S. mutans, S. sobrinus, L. casei and L. acidophilus were detected in 100% of the samples from both groups. However, brackets of the control group were more heavily contaminated by S. mutans and S. sobrinus (P < 0.01). In the experimental group, although all counts decreased after rinsing with the chlorhexidine solution, there was significant difference only for S. mutans (P = 0.03). Conclusions: The use of 0.12% chlorhexidine gluconate mouthwashes can be useful in clinical practice to reduce the levels of cariogenic microorganisms in patients under treatment with fixed orthodontic appliances. (C) 2011 Elsevier Ltd. All rights reserved.CNPq (National Council for Scientific and Technological Development)[481894/2007-1