Wall-resolved large eddy simulation over NACA0012 airfoil

The work presented here forms part of a project on Large-Eddy Simulation (LES) of aeroengine aeroacoustic interactions. In this paper we concentrate on LES of near-field flow over an isolated NACA0012 airfoil at zero angle of attack with Rec=2e5. The predicted unsteady pressure/velocity field is used in an analytically-based scheme for far-field trailing edge noise prediction. A wall resolved implicit LES or so-callednumerical Large Eddy Simulation (NLES) approach is employed to resolve streak-like structure in the near-wall flow regions. The mean and RMS velocity and pressure profile on airfoil surface and in wake are validated against experimental data and computational results from other researchers. The results of the wall-resolved NLES method are very encouraging. The effects of grid-refinement and higher-order numerical scheme on the wall-resolved NLES approach are also discussed

EPR, thermo and photoluminescence properties of ZnO nanopowders

Nanocrystalline ZnO powders have been synthesized by a low temperature solution combustion method. The photoluminescence (PL) spectrum of as-formed and heat treated ZnO shows strong violet (402, 421, 437, 485 nm) and weak green (520 nm) emission peaks respectively. The PL intensities of defect related emission bands decrease with calcinations temperature indicating the decrease of Zn i and V o + caused by the chemisorptions of oxygen. The results are correlated with the electron paramagnetic resonance (EPR) studies. Thermoluminescence (TL) glow curves of gamma irradiated ZnO nanoparticles exhibit a single broad glow peak at �343 °C. This can be attributed to the recombination of charge carriers released from the surface states associated with oxygen defects, mainly interstitial oxygen ion centers. The trapping parameters of ZnO irradiated with various γ-doses are calculated using peak shape method. It is observed that the glow peak intensity increases with increase of gamma dose without changing glow curve shape. These two characteristic properties such as TL intensity increases with gamma dose and simple glow curve structure is an indication that the synthesized ZnO nanoparticles might be used as good TL dosimeter for high temperature application. © 2011 Elsevier B.V. All Rights Reserved

Takotsubo cardiomyopathy complicating a twin pregnancy at partum

Takotsubo cardiomyopathy is a rare syndrome characterized by acute left ventricular dysfunction with regional left ventricular ballooning, mimicking myocardial infarction. This condition is often described in post-menopausal women. Authors present a case in an elderly primi with twin gestation immediately after Cesarean surgery. We discussed her presentation, investigations, diagnosis, management and outcome. 35 year female, a primi with twin pregnancy developed chest pain and shortness of breath immediately after Cesarean surgery. Her Electrocardiograph was abnormal, and Echocardiogram demonstrated abnormal apical ballooning of the left ventricle and severe dysfunction. Cardiac enzymes were elevated and chest skiagram showed pulmonary edema. She was managed in the intensive care unit with oxygen supplementation, diuretics and inotropes. She made an excellent recovery with normalization of left ventricular ejection fraction within 8 days. During the six months follow up, she was asymptomatic and left ventricular function remained normal

Hypovitamanosis D and non cardiac chest pain

Background: Recurrent atypical chest pain not due to cardiac illness is a very common condition in medical outpatient departments. Authors found that people consulting for atypical chest pain often have significant Vitamin D deficiency and correction of Vitamin D deficiency relieved patient symptoms. Hence authors carried out this study.Methods: Persons aged below 50 years were taken up for study. Those attending medical clinics with complaints of chest pain occurring more than two times were taken up for study. Cardiac illness was excluded by clinical examination and investigations. Those found to have low Vitamin D were taken up for study. 60,000 international units Vitamin D was administered orally weekly for 8 weeks. They were followed up twice weekly for three months and once monthly for three months.Results: Results were analyzed and charted. 120 subjects were taken up for study and duration of study was three years. Average age of the study group was 37.50 years and the average Vitamin D level was 15.75 nanogram/ml (ngm/ml). Duration of chest pain ranged from one week to one year. Most of the patients had migratory chest pain.Conclusions: As Vitamin D deficiency is a treatable medical condition it may be prudent to check Vitamin D levels in the patients presenting with recurrent atypical pain in the chest. It reduces the burden on the health care system and relieves the suffering of the patient. It may not be futile to check Vitamin D levels even in the patients with coronary artery disease who are suffering from atypical chest pain

Annotation and BAC/PAC localization of nonredundant ESTs from drought-stressed seedlings of anindica rice

To decipher the genes associated with drought stress response and to identify novel genes in rice, we utilized 1540 high-quality expressed sequence tags (ESTs) for functional annotation and mapping to rice genomic sequences. These ESTs were generated earlier by 3'-end single-pass sequencing of 2000 cDNA clones from normalized cDNA libraries constructed from drought-stressed seedlings of anindica rice. A rice UniGene set of 1025 transcripts was constructed from this collection through the BLASTN algorithm. Putative functions of 559 nonredundant ESTs were identified by BLAST similarity search against public databases. Putative functions were assigned at a stringency E value of 10-6 in BLASTN and BLASTX algorithms. To understand the gene structure and function further, we have utilized the publicly available finished and unfinished rice BAC/PAC (BAC, bacterial artificial chromosome; PAC, P1 artificial chromosome) sequences for similarity search using the BLASTN algorithm. Further, 603 nonredundant ESTs have been mapped to BAC/PAC clones. BAC clones were assigned by a homology of above 95% identity along 90% of EST sequence length in the aligned region. In all, 700 ESTs showed rice EST hits in GenBank. Of the 325 novel ESTs, 128 were localized to BAC clones. In addition, 127 ESTs with identified putative functions but with no homology in IRGSP (International Rice Genome Sequencing Program) BAC/PAC sequences were mapped to the Chinese WGS (whole genome shotgun contigs) draft sequence of the rice genome. Functional annotation uncovered about a hundred candidate ESTs associated with abiotic stress in rice andArabidopsis that were previously reported based on microarray analysis and other studies. This study is a major effort in identifying genes associated with drought stress response and will serve as a resource to rice geneticists and molecular biologists

Luminescence studies and EPR investigation of solution combustion derived Eu doped ZnO

ZnO:Eu (0.1 mol) nanopowders have been synthesized by auto ignition based low temperature solution combustion method. Powder X-ray diffraction (PXRD) patterns confirm the nanosized particles which exhibit hexagonal wurtzite structure. The crystallite size estimated from Scherrer's formula was found to be in the range 35-39 nm. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies reveal particles are agglomerated with quasi-hexagonal morphology. A blue shift of absorption edge with increase in band gap is observed for Eu doped ZnO samples. Upon 254 nm excitation, ZnO:Eu nanopowders show peaks in regions blue (420-484 nm), green (528 nm) and red (600 nm) which corresponds to both Eu2+ and Eu3+ ions. The electron paramagnetic resonance (EPR) spectrum exhibits a broad resonance signal at g = 4.195 which is attributed to Eu2+ ions. Further, EPR and thermoluminescence (TL) studies reveal presence of native defects in this phosphor. Using TL glow peaks the trap parameters have been evaluated and discussed. © 2014 Elsevier B.V. All rights reserved