A novel LMI-based robust model predictive control for DFIG-based wind energy conversion systems

summary:The optimal and reliable performance of doubly fed induction generator is essential for the efficient and optimal operation of wind energy conversion systems. This paper considers the nonlinear dynamic of a DFIG linked to a power grid and presents a new robust model predictive control technique of active and reactive power by the use of the linear matrix inequality in DFIG-based WECS. The control law is obtained through the LMI-based model predictive control that allows considering both economic and tracking factors by optimization of an objective function, constraints on control signal and states of system and effects of nonlinearities, generator parameter uncertainties and external disturbances. Robust stability in the face of bounded disturbances and generator uncertainty is shown using Lyapunov technique. Numerical simulations show that the proposed control method is able to meet the desired specification in active and reactive power control in the presence of varieties of wind speed and pitch angle

Infertility and physical activity: A cross-sectional study of women living in Yazd aged 20-49 yr, 2014-2015

Background: Changes in the state of energy balance owing to changes in physical activity (PA) may affect the reproductive system. Objectives: the aim of this study was to assess the association between PA and infertility of women living in Yazd 2014 - 2015. Materials and Methods: The study method was analytical cross-sectional on the Yazd Health Study (YaHS) data which was conducted on 10,000 people. We studied 2,611 women (20 and 49 yrs old), living in Greater Yazd area. PA information was collected using a physical activity questionnaire (IPAQ) short form. The standardized instruments were used for anthropometrics measurement. Results: Totally 135 cases of infertility were documented. The overall prevalence of infertility was 4.73% (95% CI: 3.94-5.59%). The median of PA scores (METs) in women was 746.66 and 25-75% interquartile range was 361.25-1277.25. The relationship according to the Chi-square test between infertility and PA, as categorized variables, was significant (p = 0.015). It showed over 90% of those who suffered from infertility had a low or moderate PA. Conclusion: The results of our study showed that there is a significant relationship between infertility and PA level in women living in Greater Yazd area. Also, women with infertility had lower activity levels, consistent with most previous studies. Key words: Women, Infertility, Physical activity, Yazd, Iran

The occurrence of antibiotic resistance, ESBLs, MBL and NDM-1 in Uropathogenic Escherichia coli in Central part of Iran

Broad-spectrum β-lactamase enzymes capable of destroying the antibiotics of β-lactam, cephalosporin, and Metallo-β-lactamase enzymes can also deactivate all β-lactams and carbapenems. This study aimed to determine ESBLs and MBLs enzymes and the frequency of NDM-1 gene­. In this study, 200 Escherichia coli isolates of women with urinary tract infection were collected (100 inpatients and 100 outpatients). Minimum inhibitory concentration (MIC) for ceftazidime and meropenem was determined by E-test. A phenotypic confirmation test was used to detect ESBL enzymes. MBLs production was performed with modified Hodge test (MHT) and EDTA disk synergy (EDS) test. PCR was used for detecting the presence of NDM-1 gene. From 200 isolates, 93 isolates produce ESBL enzymes. Overall, 97 isolates were resistant to ceftazidime, and 38 isolates resistant to meropenem. The results of the MHT and EDS positive tests were 41 and 16 isolates, respectively. NDM-1 was not found in any of the patients. The prevalence of E. coli isolates producing both ESBLs and MBLs enzymes, is a serious threat to clinical infections. Accordingly, for the control and treatment of these strains, rapid and accurate identification can be greatly helpful

Evaluation of H.pylori infection and IL23R gene polymorphism in dyspeptic subjects

CagA strains of H.pylori (Hp) are known to be associated with gastroduodenal diseases. Polymorphisms in inflammation related genes, such as cytokines and their receptors, were thought to partly determine the outcome of Hp infection and the progression of gastritis. It is supposed that interleukin 23 receptor (IL23R), a basic cytokine receptor in the inflammatory IL-17/IL-23 axis, may be related to gastritis. In the present study, we evaluated the association of IL23R +2199 rs10889677 polymorphism and cagA positivity with chronic gastritis. In addition, we studied the infiltration of polymorphonuclear (PMN) and mononuclear (MN) Leukocytes into surrounding tissues of corpus. Biopsies taken from the corpus of the patients were classified as two groups: Hp-infected and Hpuninfected. The severity of gastritis was graded from normal to severe, chronic gastritis and chronic active gastritis. Virulence factor, cagA, was evaluated using PCR and the polymorphism in IL23R was investigated by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). AA and AC carriers of IL23R +2199 polymorphism, but not CC genotype in Hp-uninfected patients, were not associated with cellular infiltration and gastritis in both groups (p > 0.05). CagA positivity was significantly associated with increased risk of PMN (P= 0.013), but not with MN infiltration (P= 0.069). Also gastritis was found to be associated with cagA positivity (P= 0.044). Our results show decreased Hp infection probability in patients with CC genotype of 2199 +IL23R. According to the clinical and pathological features in Hp-infected group, IL23R polymorphism doesn't influence chronic gastritis and chronic active gastritis

Decentralized Approximate Bayesian Inference for Distributed Sensor Network

Bayesian models provide a framework for probabilistic modelling of complex datasets. Many such models are computationally demanding, especially in the presence of large datasets. In sensor network applications, statistical (Bayesian) parameter estimation usually relies on decentralized algorithms, in which both data and computation are distributed across the nodes of the network. In this paper we propose a framework for decentralized Bayesian learning using Bregman Alternating Direction Method of Multipliers (B-ADMM). We demonstrate the utility of our framework, with Mean Field Variational Bayes (MFVB) as the primitive for distributed affine structure from motion (SfM)

Investigation of microstructure evolution on the fracture toughness behaviour of brass/low carbon steel/brass clad sheets fabricated by cold roll bonding process

The property of fracture toughness is one of the essential parameters in choosing a material that shows resistance to crack growth. In this research, the effect of microstructure evolution on the fracture toughness of Brass (CuZn10)/Low Carbon Steel (St14)/Brass (CuZn10) composite fabricated by the Cold Roll Bonding (CRB) process was investigated. For this purpose, the Brass/Low Carbon Steel/Brass three layered samples were annealed at 450 °C, 600 °C, 750 °C and 850 °C for 2 h. Uniaxial tensile test, microhardness, peeling test, EDS line scan analysis, optical microscope (OM) and scanning electron microscope (SEM) were used to characterize the properties of the composite. The compact tension (CT) test was also used to obtain the fracture toughness of samples. The EDS line scan analysis results showed that no intermetallic compound is formed at the interface of Steel and Brass layers under any temperature. However, increasing the annealing temperature causes the diffusion layer to expand from 5.13 μm to 9.02 μm for samples annealed at 450 °C and 850 °C, respectively, which aids in increasing the bond strength of the layers. Recrystallization changes the layers' microstructure, so the samples' fracture toughness was measured in the roll direction (RD) and transverse direction (TD). It was found that the value of fracture toughness is very different for the as-rolled sample in RD and TD. The most significant decrease in fracture toughness at different temperatures occurs after annealing at 600 °C, wherein the direction of RD compared to the temperature of 450 °C, more than 35% decline was recorded. In fact, after rolling, the microstructure of the layers is elongated in the direction of rolling, which makes the force-crack mouth opening in different directions not the same. Furthermore, as the temperature increases and full recrystallization occurs, the grains become equiaxed, which in addition to reducing the fracture toughness, also reduces the sensitivity to the rolling direction. Based on the obtained results, it was found that the temperature of 600 °C can be chosen as the optimal annealing temperature for three layers of Brass/Steel/Brass composite, in which the appropriate mechanical properties and fracture toughness can be obtained