Assessment of different voltage sags on performance of induction motors operated with shunt FACTS

Shunt FACTS devices are prevalent in industrial application of induction motors. These equipments are effective to compensate disturbances and increase motor speeding up. Whereas voltage sags is one of the most conventional power quality contexts in power systems, the performances of the induction motor under symmetrical and unsymmetrical voltage sags are investigated in this paper. The results prove that STATCOM is more effectual than SVC for reduction of transients and refinement the voltage profile. Between different types of unsymmetrical voltage sags, one type has maximum effect on variation range of voltage overshoot and voltage undershoot and two types have lowest influence on variation range of voltage overshoot and voltage undershoot

Detection of infectious bronchitis virus serotypes by reverse transcription polymerase chain reaction in broiler chickens

Infectious bronchitis (IB) is a highly contagious disease of the respiratory and urogenital tract of chickens, caused by infectious bronchitis virus (IBV), a member of the family Coronaviridae. The disease is common throughout the world where chickens are produced commercially. PCR on reverse transcribed RNA is a potent technique for the detection of IBV. In comparison with classical detection methods, PCR-based techniques are both sensitive and fast. Dozens of serotypes and genotypes of IBV have been detected, and many more will surely be reported in future. This research was conducted to identify the infectious bronchitis virus with group specific primers of avian Coronaviruses in Zabol, southeast of Iran. Tracheal swabs were collected from eleven commercial broiler flocks and these swabs were used for RNA extraction. General primers included XCE2+ and XCE2- that amplify all IBV serotypes were used. Primers MCE1+, BCE1+ and DCE1+ was used to amplifying the specific nucleotide sequence of Massachusetts, 4/91 and D274 serotypes, respectively. The results of this study showed that 36.36% of the sampled flocks were positive to IBV by RT-PCR. Moreover, the Massachusetts was the identified serotype of infectious bronchitis virus. The results provide the first molecular evidence for the presence of infectious bronchitis virus and Massachusetts serotype in Zabol. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/2193-1801-2-36) contains supplementary material, which is available to authorized users

Isolamento de Cryptococcus neoformans de excrementos de andorinhas (Hirundo rustica) do Irã

Cryptococcus neoformans is an encapsulated yeast that can cause cryptococcosis, a life-threatening infection that mainly occurs in immunocompromised patients. The major environmental sources of C. neoformans have been shown to be soil contaminated with avian droppings. In the present study, we evaluated the isolation of C. neoformans from swallow (Hirundo rustica) excreta in two northern cities of Iran. Ninety-seven swallow droppings were evaluated and 498 yeast-like colonies were isolated and identified as Rhodotorula spp. (62.8%), Candida spp. (28.5%)and C. neoformans (8.7%). Cryptococcus neoformans was isolated from 5/97 (5.2%) of collected samples. Min-Max colony forming units (CFU) per one gram for the positive samples were 3-10 C. neoformans colonies. The total mean CFU per one gram for the positive samples was 4.8. The results of this study demonstrate that excreta of swallow may harbor different species of potentially pathogenic yeasts, mainly C. neoformans, and may be capable of disseminating these fungi in the environment.Cryptococcus neoformans é levedura encapsulada que pode causar criptococose, infecção potencialmente mortal que ocorre principalmente em pacientes imunocomprometidos. As principais fontes ambientais de C. neoformans são o solo contaminado com fezes de aves. No presente estudo, avaliamos o isolamento de C. neoformans de excreta de andorinhas (Hirundo rustica) em duas cidades do norte do Irã. Noventa e sete amostras de fezes de andorinhas foram avaliadas e 498 colonias semelhantes à levedura foram isoladas e identificadas como Rhodotorula spp. (62,8%), Candida spp. (28,5%), C. neoformans (8,7%). Cryptococcus neoformans foi isolado a partir de 5/97 (5,2%) das amostras coletadas. Unidades Min-Max formadoras de colonias (CFU) por 1 grama das amostras positivas foram 3-10 coloniasde C. neoformans. A média total de CFU por 1 grama das amostras positivas foi de 4,8. Os resultados deste estudo demonstram que excrementos de andorinhas podem abrigar diferentes espécies de leveduras potencialmente patógenas, principalmente C. neoformans, e podem ser capazes de disseminar estes fungos no meio ambiente

Effects of Endurance and Resistance Training on Calcitonin Gene-Related Peptide and Acetylcholine Receptor at Slow and Fast Twitch Skeletal Muscles and Sciatic Nerve in Male Wistar Rats

The aim of this study was to investigate effects of endurance and resistance training (ET and RT) on CGRP and AChRs at slow and fast twitch muscles and sciatic nerve in rats. Twenty-five male rats were randomly assigned into three groups including sedentary (SED), endurance training (ET), and resistance training (RT). Animals of ET exercised for 12 weeks, five times/week, and 60 min/day at 30 m/min. Animals of RT were housed in metal cage with 2 m high wire-mesh tower, with water bottles set at the top. 48 h after the last session of training protocol, animals were anaesthetized. The right sciatic nerves were removed; then, Soleus (SOL) and Tibialis anterior (TA) muscles were excised and immediately snap frozen in liquid nitrogen. All frozen tissues were stored at −80°C. Results showed that, after both ET and RT, CGRP content as well as AChR content of SOL and TA muscles significantly increased. But there was no significant difference among groups at sciatic nerve' CGRP content. In conclusion, data demonstrate that ET and RT lead to changes of CGRP and AChR content of ST and FT muscles. The changes indicate to the importance of neuromuscular activity

MYCN Gene Copy Number Status Detected by FISH Method and Its Correlation with Outcome and Clinicopathological Variables in Childhood Neuroblastoma

Background: Neuroblastoma is the most common extracranial solid tumor in children. MYCN gene amplification (MNA) is an independent prognostic factor for rapid tumor progression and poor prognosis, regardless of age and clinical stage. Gain of the MYCN gene locus on the short arm of chromosome 2 can also be found in neuroblastoma.Method: In this retrospective descriptive analysis of genetic alterations in neuroblastoma tumor samples, both before and after standard chemotherapy, we examined the MYCN gene copy number status in 20 neuroblastic tumor samples using the fluorescence in situ hybridization (FISH) method. We also evaluated its relationship with clinical variables and tumor maturation after standard chemotherapy treatment. Additionally, we compared disease outcomes among different MYCN copy number categories.Results: Among the tumor samples, four (25%) exhibited increased MYCN copy numbers, 20% showed MYCN amplification, and 5% displayed MYCN gain. We observed decreased survival rates in advanced stages of neuroblastoma. Furthermore, in male patients, we noted an association between increased MYCN copy number and metastatic tumors.Conclusion: We found that increased MYCN copy number is moderately associated with an immature phenotype and correlated with lower event-free survival. However, we did not detect a statistically significant difference

Design of robust controller for STATCOM applied to large induction motor using normalized coprime factorization approach

Between the different robust H-infinity methods to design the controller for FACTS, loop shaping is known to be one of the effective and feasible methods. This research presents an investigation on H-infinity loop shaping procedure through normalized coprime factorization (NCF) for STATCOM installed at terminals of a large induction motor. The dynamic behaviors of induction motor are analyzed while the uncertainty of system parameters and STATCOM parameters are considered and will be compared with conventional PI controller. Simulation results prove that NCF method has better dynamic response and is more robust than PI controller against variation of system parameters and STATCOM parameters, so in a specified operating point even the system goes to instability

Performance study of drive systems and shunt FACTS for the operation of induction motors

Drive systems are prevalent in industrial application of induction motors; while shunt FACTS devices are important to compensate disturbances and increase motor speeding up. In this paper an assessment study between Space Vector PWM (SVM) induction motor drive system and shunt FACTS (such as SVC) installed on terminals of motor is done. It is shown that shunt FACTS is more suitable than Induction motor drive system for decreasing of time of speeding up. The results of simulations also display that STATCOM has better response over SVC for improving dynamic behavior of induction motor and effectual for reduction of transients and refinement the voltage profile

Investigating the performance of shunt FACTS for the operation of induction motors under different voltage sag conditions

Shunt FACTS devices are prevalent in industrial application of induction motors. These equipments are effective to compensate disturbances and increase motor speeding up. In this study an assessment study between two different shunt FACTS (SVC and STATCOM) installed on terminals of motor is done. A conventional PI controller is used to control the thyristor firing angle of SVC or phase angle of STATCOM. A pole placement method is applied to specify the perfect gain settings of the controllers. The results of simulations display that STATCOM has better response over SVC for improving dynamic behavior of induction motor under ideal supply conditions. Power quality problem that influence the dynamic behavior of induction motor, include non ideal conditions such as harmonics, interruptions, voltage unbalance and voltage sags. Whereas voltage sags is one of the main cause of disturbances in distribution systems, the performances of the induction motor under symmetrical and unsymmetrical voltage sags are investigated in this study. The results prove that STATCOM is more effectual than SVC for reduction of transients and refinement the voltage profile

A short review of different optimal H∞ robust FACTS controller designs

A review of designing the Optimize Robust FACTS Controller to provide better dynamic performance in power system is presented. The design is carried out applying robustness criteria for stability and performance. Variations of system operation conditions are represented by uncertainty model. Besides, Linear Fractional Transformation (LFT) form together with model reduction techniques are used to design a low order controller which provides fast and stable response under all system conditions. Furthermore, comparison different H∞ robust approaches specify advantages and disadvantages of every method. It is shown that one method has more flexibility and convenience