14 research outputs found

    Fault diagnosis of squirrel cage induction generator for wind turbine applications using a hybrid deep neural network and decision tree approach

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    Phase-to-Phase Fault (PPF) and Phase-to-Ground Fault (PGF) are among common electrical faults in wind turbine generators. Detecting and classifying these faults at early stage are hence vital to improving drivetrain reliability and reduce its maintenance cost. In this paper, a hybrid approach based on the Decision Tree (DT) and Deep Neural Network (DNN) is proposed as a high-performance fault diagnosis method to detect and classify PPF and PGF in the squirrel cage induction generator (SCIG). The DT algorithm is used to detect the faulty conditions in the generator by determining special features in the stator current signals. CNN model will then be used to determine the type of fault by analysing the fault signals. Finally, the accuracy of the proposed fault diagnosis approach is evaluated by simulating a 1.7 MW SCIG wind turbine drivetrain at healthy and faulty conditions

    Wind Turbine Generator Short Circuit Fault Detection Using a Hybrid Approach of Wavelet Transform and Naïve Bayes Classifier

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    Wind turbines are subjected to several failure modes during their operation. A wind turbine drivetrain generally consists of rotor, bearings, low and high-speed shafts, gearbox, brakes, and generator. Single phase-to-phase and single phase-to-ground faults are among common electrical failure modes in the generator. In this paper, feature extraction has been performed using the Discrete Wavelet Transform (DWT) to detect the electrical faults in the wind turbine generator. A two-stage prediction process is proposed using Naïve Bayes Classifier (NBC), where the healthy and faulty modes are first determined, followed by classifying the types of electrical faults. Three-phase stator currents are used as fault detection signals. The performance of the proposed algorithm has been evaluated in Simulink for a 1659 kW wind turbine drivetrain

    Global, regional, and national burden of colorectal cancer and its risk factors, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019

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    Funding: F Carvalho and E Fernandes acknowledge support from Fundação para a Ciência e a Tecnologia, I.P. (FCT), in the scope of the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy i4HB; FCT/MCTES through the project UIDB/50006/2020. J Conde acknowledges the European Research Council Starting Grant (ERC-StG-2019-848325). V M Costa acknowledges the grant SFRH/BHD/110001/2015, received by Portuguese national funds through Fundação para a Ciência e Tecnologia (FCT), IP, under the Norma Transitória DL57/2016/CP1334/CT0006.proofepub_ahead_of_prin

    ZLoc: A C++ library for local search

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    Local search is known as an effective technique for solving combinatorial optimization problems. However, there are few tools that provide high level facilities for users to implement their own local search algorithms. In this paper, we introduce ZLoc, a new C++ library for local search. ZLoc supports many high-level features usually found in modeling languages, such as Zinc. It allows users to define their models in terms of variables and constraints, then it specifies their favorite local search method for solving the mode

    Cryptosporidium Infection in Patients with Gastroenteritis in Sari, Iran

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    Background: Cryptosporidiosis is a common coccidian parasite infection in patients with diarrhea that has worldwide distribution especially in developed countries. Therefore,the aim of this study was to determine the occurrence of Cryptosporidium infection in patients with gastroenteritis admitted to hospitals of Mazandaran University of Medical Sciences by parasitological and molecular methods in Sari, Iran. Methods: Stool samples were collected from 348 patients with gastroenteritis admitted to the hospitals of Medical University in the Sari and Ghaemshahr cities in Mazandaran Province, Northern Iran in 2010-2011. Oocysts of Cryptosporidium identified using Formalin-Ether concentration method and stained by Aacid-fast staining (AFS)and Auramine phenol fluorescence (APF). Genomic DAN extracted from microscopically positive samples and nested PCR -RFLP by using SSU rRNA that identifies of the species of cryptosporidium. Results: In 348 patients with gastroenteritis, the most clinical symptoms were diarrhea, nausea, vomiting, dehydration, fever and weight loss. 2.3% (8 cases) of diarrheal samples tested by both microscopy and molecular methods were positive for the presence of cryptosporidium. Nested PCR products yielded unique bands of 846 bp, correspond to cryptosporidium. Species diagnosis carried out by digesting the secondary PCR product with SspI restriction enzyme, which noted 3 clearly bands of 449, 254, and 108 bp correspond to Cryptosporidium spp. Conclusion: The results of present study on Cryptosporidium spp. in this area can make a background data for control programs and further molecular analyses. Thus, further work needs to determine the origin of Cryptosporidium species in this area

    What is the impact of cinnamon supplementation on blood pressure? A systematic review and meta-analysis

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    Aim: This study was designed to make a systematic review and meta-analysis on randomized controlled trials (RCTs) assessing the effect of cinnamon on blood pressure (BP). Methods: A systematic computerized literature search of PubMed, Scopus, Web of Science, Cochrane Library and Google Scholar databases was conducted up to August 2019. All RCTs using cinnamon supplements in adults were included in this systematic review and metaanalysis. Results: Out of 927 records, 8 trials that enrolled 582 participants were included. The pooled effect size showed that SBP did not change following cinnamon supplementation. (WMD: 0.61mmHg; 95% CI: -1.36, 0.14, P= 0.111). Also cinnamon supplementation in long-duration (≥ 8weeks) had a significant effect on SBP (WMD: -1.25 mmHg; 95% CI: -2.22, -0.28, P= 0.012). Pooled analysis showed that cinnamon had a significant effect on DBP (WMD: -0.93mmHg, 95% CI: -1.55 to -0.32, P= 0.003). In addition, results from both duration subsets and high dose (>1500 mg/day) of cinnamon supplementation were significant. Conclusion: Our findings revealed that cinnamon supplementation has favorable effects on DBP although results of SBP were not the same. Nonetheless, further studies are required

    Comparison of serum levels of Tri‐iodothyronine (T3), Thyroxine (T4), and Thyroid‐Stimulating Hormone (TSH) in preeclampsia and normal pregnancy

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    Background: The physiological changes in thyroid gland during pregnancy have been suggested as one of the pathophysiologic causes of preeclampsia.Objective: The aim of this study was comparison of serum levels of Tri‐iodothyronine (T3), Thyroxine (T4), and Thyroid‐Stimulating Hormone (TSH) in preeclampsia and normal pregnancy. Materials and Methods: In this case‐control study, 40 normal pregnant women and 40 cases of preeclampsia in third trimester of pregnancy were evaluated. They were compared for serum levels of Free T3 (FT3), Free T4 (FT4) and TSH. The data was analyzed by SPSS software with the use of t‐student, Chi‐square, Independent sample T-test and Bivariate correlation test. p≤0.05 was considered statistically significant. Results: The mean age was not statistically different between two groups (p=0.297). No significant difference was observed in terms of parity between two groups (p=0.206). Normal pregnant women were not significantly different from preeclampsia cases in the view of FT3 level (1.38 pg/ml vs. 1.41 pg/ml, p=0.803), FT4 level (0.95 pg/ml vs. 0.96 pg/ml, p=0.834) and TSH level (3.51 μIU/ml vs. 3.10 μIU/ml, p=0.386). Conclusion: The findings of the present study do not support the hypothesis that changes in FT3, FT4 and TSH levels could be possible etiology of preeclampsi

    Effects of tarragon powder on glucose metabolic changes, lipid profile and antioxidant enzyme levels in type 2 patients with diabetes: A randomized, double-blind, placebo-controlled, clinical trial

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    Background: The antioxidant and anti-inflammatory properties of tarragon make it known as an antidiabetic plant. Diabetes mellitus, an endocrine, metabolic disease, is a leading global health emergency and associated with serious complications. Objectives: This study aimed to assess the effects of tarragon powder supplementation on glucose metabolism, lipid profile, and antioxidant status in the diabetic population. Methods: Patient screening and selection for this clinical trial lasted one month. Tarragon supplement consumption by patients lasted 2 months (8 weeks); meanwhile, they were followed up. Sixty male and female patients with type 2 diabetes were randomly assigned to the tarragon receiver group (n = 30) and placebo receiver group (n = 30). The intervention group received a tarragon capsule (500 mg) 3 times a day, and the control group received placebo capsules. Fasting blood glucose (FBG), two-hour postprandial glucose (2-hpp), glycated hemoglobin (HbA1c), insulin, lipid, and antioxidant profile were evaluated at the start and the end of the research. Results: In the tarragon receiver group, FBG, 2-hpp, HbA1c%, insulin resistance, lipid, and antioxidant profile significantly improved, compared to the placebo group, after adjuvant therapy with tarragon (P < 0.05). Conclusions: Supplementation with tarragon powder in type II patients with diabetes for 2 months exerts a beneficial effect on improving the glycemic profile, lipid profile, and antioxidant statu
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