A Review on Stability Improvement of Wind Farm using FACTS Device

This paper represents a review on Stability improvement of wind farm using the Flexible AC Transmission System (FACTS) device. FACTS devices are used to increase the transient stability on the presence of faults and the integration of renewable sources, like wind energy. Due to continuously varying wind speed and also due to fault the active and reactive power along with terminal voltage fluctuates continuously. By connecting Static Synchronous Compensator (STATCOM) into the grid, the active power, reactive power, and terminal voltage are maintained constant and also help to improve the transient stability of the system

The Effect of Recruitment and Employee Selection on Employee Placement and Its Impacts Towards Employee Performance at PT Sriwijaya Air

Sriwijaya Air realizes the importance of candidates selection of process, because this process will result in employees in accordance with the prescribed qualifying so as to achieve a performance from these new employees. The purpose of this study was to determine the effect of the implementation of the recruitment and placement of employees selection and its impact on the performance of employees of PT Sriwijaya Air Jakarta. The analytical method used is the method of path analysis. The results showed that recruitment and selection variables influence significantly on the placement of employees. Likewise, employee placement variable influence significantly on the performance of employees of PT Sriwijaya Air Jakarta. However, only recruitment variable that Significantly influence on employee performance. Recruitment is one - the only variable that has direct influence on employee performance. While selection and placement of employees variable do not affect the performance of employees

Stability Improvement of Power System due to Wind Farm and Fault using FACTS Devices

Wind energy is gaining the most interest among a variety of renewable energy resources, but the disadvantage is that wind power generation is intermittent, depending on weather conditions. FACTS devices are used to increase the transient stability on the presence of faults and the integration of renewable sources, like wind energy. Due to continuously varying wind speed components and also due to fault the active and reactive power along with terminal voltage fluctuates continuously. STATCOM and UPFC are two important FACTS devices; provide the desired reactive-power generation and absorption, entirely using electronic processing of the voltage and current waveforms in a voltage source converter (VSC). By connecting STATCOM and UPFC into the lines, the active power, reactive power, and terminal voltage is maintained constant and it also helps to improve the transient stability of the system. STATCOM can control voltage magnitude and, to a small extent, the phase angle in a very short time and UPFC can control voltage magnitude as well as phase angle and therefore, can improve the system performance. In this paper, improvement of transient stability in wind farm under fault have been studied using STATCOM and UPFC in MATLAB SIMULINK software

A Review on Stability Improvement of Wind Farm Using FACTS Device

This paper represents a review on Stability improvement of wind farm using the Flexible AC Transmission System (FACTS) device. FACTS devices are used to increase the transient stability on the presence of faults and the integration of renewable sources, like wind energy. Due to continuously varying wind speed and also due to fault the active and reactive power along with terminal voltage fluctuates continuously. By connecting Static Synchronous Compensator (STATCOM) into the grid, the active power, reactive power, and terminal voltage are maintained constant and also help to improve the transient stability of the system

Stability Improvement of Power System Due to Wind Farm and Fault Using FACTS Devices

Wind energy is gaining the most interest among a variety of renewable energy resources, but the disadvantage is that wind power generation is intermittent, depending on weather conditions. FACTS devices are used to increase the transient stability on the presence of faults and the integration of renewable sources, like wind energy. Due to continuously varying wind speed components and also due to fault the active and reactive power along with terminal voltage fluctuates continuously. STATCOM and UPFC are two important FACTS devices; provide the desired reactive-power generation and absorption, entirely using electronic processing of the voltage and current waveforms in a voltage source converter (VSC). By connecting STATCOM and UPFC into the lines, the active power, reactive power, and terminal voltage is maintained constant and it also helps to improve the transient stability of the system. STATCOM can control voltage magnitude and, to a small extent, the phase angle in a very short time and UPFC can control voltage magnitude as well as phase angle and therefore, can improve the system performance. In this paper, improvement of transient stability in wind farm under fault have been studied using STATCOM and UPFC in MATLAB SIMULINK software

A prospective study of risk factor profile & incidence of deep venous thrombosis among medically-ill hospitalized patients at a tertiary care hospital in Northern India

Background & Objective: Hospitalization for medical-illness is associated with an increased risk of deep venous thrombosis (DVT). However, there are no published data from India addressing at this issue. We sought to study the risk factor profile and the incidence of DVT among hospitalized medically-ill patients, a tertiary care hospital in northern India. Methods: All adults admitted to the medical wards and intensive care unit with level 1 or 2 mobility over a period of two years (July 2006 to July 2008) at the All India Institute of Medical Sciences hospital, New Delhi, were prospectively studied. Patients having DVT at admission or an anticipated hospital stay less than 48 h were excluded. The presence of clinical risk factors for DVT was recorded and laboratory evaluation was done for hypercoagulable state. A routine surveillance venous compression Doppler ultrasonography was performed 12 ± 8 days after hospital admission. Results: Of the 163 patients, 77 (47%) had more than one risk factor for DVT. Five (3%) patients developed DVT; none of them had symptomatic DVT. None of these patients received anticoagulation prior to the development of DVT. The mean age of those who developed DVT was 40 ± 13 (25-50) yr; two of five were male. The incidence rate of DVT was 2.7 per 1000 person-days of hospital stay [95% confidence interval (CI): 0.87 to 6.27]. None of the factors was found to be significantly associated with the risk of DVT. Interpretation & Conclusion: In our setting, although many hospitalized medically-ill patients had risk factors for DVT, the absolute risk of DVT was low compared to the western population but clearly elevated compared to non hospitalized patients. Large studies from India are required to confirm our findings

High degree of mitochondrial gene heterogeneity in the bat tick species Ixodes vespertilionis, I. ariadnae and I. simplex from Eurasia

Background: Phylogeographical studies allow precise genetic comparison of specimens, which were collected over large geographical ranges and belong to the same or closely related animal species. These methods have also been used to compare ticks of veterinary-medical importance. However, relevant data are missing in the case of ixodid ticks of bats, despite (1) the vast geographical range of both Ixodes vespertilionis and Ixodes simplex, and (2) the considerable uncertainty in their taxonomy, which is currently unresolvable by morphological clues. Methods: In the present study 21 ticks were selected from collections or were freshly removed from bats or cave walls in six European and four Asian countries. The DNA was extracted and PCRs were performed to amplify part of the cytochrome oxidase I (COI), 16S and 12S rDNA genes, followed by sequencing for identification and molecular-phylogenetic comparison. Results: No morphological differences were observed between Ixodes vespertilionis specimens from Spain and from other parts of Europe, but corresponding genotypes had only 94.6 % COI sequence identity. An I. vespertilionis specimen collected in Vietnam was different both morphologically and genetically (i.e. with only 84.1 % COI sequence identity in comparison with I. vespertilionis from Europe). Two ticks (collected in Vietnam and in Japan) formed a monophyletic clade and shared morphological features with I. ariadnae, recently described and hitherto only reported in Europe. In addition, two Asiatic specimens of I. simplex were shown to differ markedly from European genotypes of the same species. Phylogenetic relationships of ticks showed similar clustering patterns with those of their associated bat host species. Conclusions: Although all three ixodid bat tick species evaluated in the present study appear to be widespread in Eurasia, they exhibit pronounced genetic differences. Data of this study also reflect that I. vespertilionis may represent a species complex

Listening carefully: increased perceptual acuity for species discrimination in multispecies signalling assemblages

Communication is a fundamental component of evolutionary change because of its role in mate choice and sexual selection. Acoustic signals are a vital element of animal communication and sympatric species may use private frequency bands to facilitate intraspecific communication and identification of conspecifics (acoustic communication hypothesis, ACH). If so, animals should show increasing rates of misclassification with increasing overlap in frequency between their own calls and those used by sympatric heterospecifics. We tested this on the echolocation of the horseshoe bat, Rhinolophus capensis, using a classical habituation-dishabituation experiment in which we exposed R. capensis from two phonetic populations to echolocation calls of sympatric and allopatric horseshoe bat species (Rhinolophus clivosus and Rhinolophus damarensis) and different phonetic populations of R. capensis. As predicted by the ACH, R. capensis from both test populations were able to discriminate between their own calls and calls of the respective sympatric horseshoe bat species. However, only bats from one test population were able to discriminate between calls of allopatric heterospecifics and their own population when both were using the same frequency. The local acoustic signalling assemblages (ensemble of signals from sympatric conspecifics and heterospecifics) of the two populations differed in complexity as a result of contact with other phonetic populations and sympatric heterospecifics. We therefore propose that a hierarchy of discrimination ability has evolved within the same species. Frequency alone may be sufficient to assess species membership in relatively simple acoustic assemblages but the ability to use additional acoustic cues may have evolved in more complex acoustic assemblages to circumvent misidentifications as a result of the use of overlapping signals. When the acoustic signal design is under strong constraints as a result of dual functions and the available acoustic space is limited because of co-occurring species, species discrimination is mediated through improved sensory acuity in the receiver