Reliability assessment of microgrid with renewable generation and prioritized loads

With the increase in awareness about the climate change, there has been a tremendous shift towards utilizing renewable energy sources (RES). In this regard, smart grid technologies have been presented to facilitate higher penetration of RES. Microgrids are the key components of the smart grids. Microgrids allow integration of various distributed energy resources (DER) such as the distributed generation (DGs) and energy storage systems (ESSs) into the distribution system and hence remove or delay the need for distribution expansion. One of the crucial requirements for utilities is to ensure that the system reliability is maintained with the inclusion of microgrid topology. Therefore, this paper evaluates the reliability of a microgrid containing prioritized loads and distributed RES through a hybrid analytical-simulation method. The stochasticity of RES introduces complexity to the reliability evaluation. The method takes into account the variability of RES through Monte- Carlo state sampling simulation. The results indicate the reliability enhancement of the overall system in the presence of the microgrid topology. In particular, the highest priority load has the largest improvement in the reliability indices. Furthermore, sensitivity analysis is performed to understand the effects of the failure of microgrid islanding in the case of a fault in the upstream network

Experimental investigation of some aspects of insect-like flapping flight aerodynamics for application to micro air vehicles

Insect-like flapping flight offers a power-efficient and highly manoeuvrable basis for micro air vehicles for indoor applications. Some aspects of the aerodynamics associated with the sweeping phase of insect wing kinematics are examined by making particle image velocimetry measurements on a rotating wing immersed in a tank of seeded water. The work is motivated by the paucity of data with quantified error on insect-like flapping flight, and aims to fill this gap by providing a detailed description of the experimental setup, quantifying the uncertainties in the measurements and explaining the results. The experiments are carried out at two Reynolds numbers-500 and 15,000-accounting for scales pertaining to many insects and future flapping-wing micro air vehicles, respectively. The results from the experiments are used to describe prominent flow features, and Reynolds number-related differences are highlighted. In particular, the behaviour of the leading-edge vortex at these Reynolds numbers is studied and the presence of Kelvin-Helmholtz instability observed at the higher Reynolds number in computational fluid dynamics calculations is also verified

Second Backbend in the Mass A ~ 180 Region

Within the framework of selfconsistent cranked Hartree-Fock- Bogoliubov theory(one-dimensional) we predict second backbend in the yrast line of Os-182 at $I \approx 40$, which is even sharper than the first one observed experimentally at $I \approx 14$. Around such a high spin the structure becomes multi-quasiparticle type, but the main source of this strong discontinuity is a sudden large alignment of i_13/2 proton orbitals along the rotation axis followed soon by the alignment of j_15/2 neutron orbitals. This leads to drastic structural changes at such high spins. When experimentally confirmed, this will be observed for the first time in this mass region, and will be at the highest spin so far.Comment: 13 pages, 4 ps figure

Morphology of Tigris River within Baghdad City

In recent years, substantial changes have occurred in the morphology of the River Tigris within Baghdad City. Although huge volumes of sediment are being trapped in recently constructed headwater reservoirs, the number of islands in the Tigris at Baghdad is increasing. The debris of bridges destroyed in the wars of 1991 and 2003 and their subsequent reconstruction have enhanced the development of these islands. As a consequence the ability of the river to carry the peaks of flood waters has been reduced. This has led to potential increase of flooding in parts of the city. <br><br> The bed of the River Tigris has been surveyed on three occasions (1976, 1991, and 2008). The most recent survey was conducted by the Ministry of Water Resources, extended 49 km from the Al-Muthana Bridge north Baghdad to the confluence with the Diyala River south Baghdad. It yielded cross-section profiles at 250 m intervals. The data are used to predict the maximum flood capacity for the river using the one-dimensional hydraulic model for steady flow "HEC-RAS" modeling. Calibration of the model was carried out using field measurements for water levels along the last 15 km of the reach and the last 10 yr of observation at the Sarai Baghdad gauging station. <br><br> The model showed a significant predicted reduction in the current river capacity below that which the river had carried during the floods of 1971 and 1988. The three surveys conducted on the same reach of the Tigris indicated that the ability of the river to transport water has decreased

The prevalence of domestic violence among pregnant women in Nigeria: a systematic review.

To identify, appraise, and synthesize research evidence on the prevalence of domestic violence (DV) among pregnant women in Nigeria. We conducted a systematic review of all published studies between April 2004 and June 2016. Comprehensive searches were conducted on electronic databases such as PubMed, CINAHL, Global Health, MEDLINE, PsycINFO, Directory of Open Access Journals, Google Scholar, and electronic libraries of the authors' institution. Identified articles were screened in two stages against the inclusion criteria with titles and abstract screened first followed by full-text screening. Selected articles were assessed using the "guidelines for evaluating prevalence studies," and findings were synthesized narratively. Among 19 studies that met the inclusion criteria, two articles were excluded due to low methodological quality and 17 articles were included in the review. The prevalence of DV during pregnancy in Nigeria ranged between 2.3% and 44.6% with lifetime prevalence rates ranging between 33.1% and 63.2%. Physical, sexual, psychological, and verbal abuses were the most frequent types of DV reported in this review. The most common perpetrators were husbands, as reported in 11 of the 17 studies. Pregnant women between the ages of 20 and 30 years were the most common victims of DV. Our review suggests high prevalence of DV in pregnancy among women in Nigeria and higher lifetime prevalence. However, determining an overall, synthesized accurate prevalence rate of DV within this population based on existing evidence presents a challenge. The findings have important implications for stakeholders such as planners, policy makers, maternity care providers, and researchers in public health and social policy at national, regional, and international levels toward combating the issue. OBJECTIVE METHOD RESULTS CONCLUSIO

Development of a stability-indicating high performance liquid chromatographic method for the analysis of topiramate and dissolution rate testing in topiramate tablets

A stability-indicating high performance liquid chromatographic(HPLC) method was developed and validated for the quantitation and dissolution determination of topiramate in tablet dosage forms. An isocratic separation was achieved using a phenyl column with a flow rate of 1 mL/min using UV detection at 264 nm. Topiramate has low UV absorbtivity and was subjected to derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl). The mobile phase for the separation consisted of acetonitrile: 50 mM sodium dihydrogen phosphate(NaH2PO4) containing 3 % v/v triethylamine (pH 2.8) in a 48:52 v/v ratio. Topiramate was subjected to oxidation, hydrolysis, photolysis and heat for the purposes of stress testing. Separation was achieved for the parent compound and all the degradation products in an overall analytical run time of approximately 15 min with the parent compound topiramate eluting at approximately 9.2 min. The method was linear over the concentration range of 1-100 μg/mL (r = 0.9996) with limits of quantitation and detection of 1 and 0.3 μg/mL, respectively

Optimal Microlensing Observations

One of the major limitations of microlensing observations toward the Large Magellanic Cloud (LMC) is the low rate of event detection. What can be done to improve this rate? Is it better to invest telescope time in more frequent observations of the inner high surface-brightness fields, or in covering new, less populated outer fields? How would a factor 2 improvement in CCD sensitivity affect the detection efficiency? Would a series of major (factor 2--4) upgrades in telescope aperture, seeing, sky brightness, camera size, and detector efficiency increase the event rate by a huge factor, or only marginally? I develop a simplified framework to address these questions. With observational resources fixed at the level of the MACHO and EROS experiments, the biggest improvement (factor ~2) would come by reducing the time spent on the inner ~25 deg^2 and applying it to the outer ~100 deg^2. By combining this change with the characteristics of a good medium-size telescope (2.5 m mirror, 1" point spread function, thinned CCD chips, 1 deg^2 camera, and dark sky), it should be possible to increase the detection of LMC events to more than 100 per year (assuming current estimates of the optical depth apply to the entire LMC).Comment: Submitted to ApJ, 13 pages plus 3 figure

Microlens Parallaxes with SIRTF

The Space Infrared Telescope Facility (SIRTF) will drift away from the Earth at about 0.1 AU/yr. Microlensing events will therefore have different characteristics as seen from the satellite and the Earth. From the difference, it is possible in principle to measure v-tilde, the transverse velocity of the lens projected onto the observer plane. Since v-tilde has very different values for different populations (disk, halo, Large Magellanic Cloud), such measurements could help identify the location, and hence the nature, of the lenses. I show that the method previously developed by Gould for measuring such satellite parallaxes fails completely in the case of SIRTF: it is overwhelmed by degeneracies which arise from fact that the Earth and satellite observations are in different band passes. I develop a new method which allows for observations in different band passes and yet removes all degeneracies. The method combines a purely ground-based measurement of the "parallax asymmetry" with a measurement of the delay between the time the event peaks at the Earth and satellite. In effect, the parallax asymmetry determines the component of v-tilde in the Earth-Sun direction, while the delay time measures the component of v-tilde in the direction of the Earth's orbit.Comment: 21 pages plus 3 figure

Nonclassical Light in Interferometric Measurements

It is shown that the even and odd coherent light and other nonclassical states of light like superposition of coherent states with different phases may replace the squeezed light in interferometric gravitational wave detector to increase its sensitivity. (Contribution to the Second Workshop on Harmonic Oscillator, Cocoyoc, Mexico, March 1994)Comment: 8 pages,LATEX,preprint of Naples University, INFN-NA-IV-94/30,DSF-T-94/3