Analysis of melt-textured YBCO with nanoscale inclusions

Recently, particles with the chemical composition Y2Ba 4CuMOx where M U, Nb, Zr, etc., and sizes in the range of 50 - 200 nm have been generated within the YBCO matrix of bulk, melt-processed superconductors in order to serve as effective flux pinning sites. By means of AFM and electron backscatter diffraction (EBSD) measurements, we analyse the spatial distribution and the size distribution of these nanoparticles within the superconducting YBCO matrix

Investigation of grain orientations of melt-textured HTSC with addition of uranium oxide, Y2O3 and Y2BaCuO5

Local grain orientations were studied in melt-textured YBCO samples processed with various amounts of depleted uranuim oxide (DU) and Y 2O3 by means of electron backscatter diffraction (EBSD) analysis. The addition of DU leads to the formation of Ucontaining nanoparticles (Y2Ba4CuUOx) with sizes of around 200 nm, embedded in the superconducting Y-123 matrix. The orientation of the Y 2BaCuO5 (Y-211) particles, which are also present in the YBCO bulk microstructure, is generally random as is the case in other melttextured Y-123 samples. The presence of Y-211 particles, however, also affects the orientation of the Y-123 matrix in these samples

EBSD characterisation of Y2Ba4CuUOx phase in melttextured YBCO with addition of depleted uranium oxide

Melt-textured YBCO samples processed with added Y2O3 and depleted uranium oxide (DU) contain nano-particles, which have been identified previously as Y2Ba4CuUOx (U-411). This phase has a cubic unit cell, which is clearly distinct from the orthorhombic Y-123 and Y-211 phases within the YBCO system. In samples with a high amount of DU addition (0.8 wt-% DU), U-2411 particles have sizes between 200 nm and several νm, so identification of the Kikuchi patterns of this phase becomes possible. Together with a parallel EDX analysis, the particles embedded in the Y-123 matrix can be identified unambiguously. In this way, a three-phase EBSD scan becomes possible, allowing also the identification of nanometre-sized particles in the sample microstructure

Growth rate of YBCO single grains containing Y-2411(M)

Y-Ba-Cu-O (YBCO) single grains have the potential to generate large trapped magnetic fields for a variety of engineering applications, and research on the processing and properties of this material has attracted world-wide interest. In particular, the introduction of flux pinning centres to the large grain microstructure to improve its current density, Jc, and hence trapped field, has been investigated extensively over the past decade. Y 2Ba4CuMOx [Y-2411(M)], where M = Nb, Ta, Mo, W, Ru, Zr, Bi and Ag, has been reported to form particularly effective flux pinning centres in YBCO due primarily to its ability to exist as nano-size inclusions in the superconducting phase matrix. However, the addition of the Y-2411(M) phase to the precursor composition complicates the melt-processing of single grains. We report an investigation of the growth rate of single YBCO grains containing Y-2411(Bi) phase inclusions and Y2O3. The superconducting properties of these large single grains have been measured specifically to investigate the effect of Y2O3 on broadening the growth window of these materials

Complete androgenin sensitivity syndrome presenting with primary amenorrhoea and inguinal mass: a case report

Androgen insensitivity syndrome (AIS), also known as testicular feminization, an X-linked recessive disorder comprises a wide range of phenotypes that are caused by various types of mutations in the androgen receptor gene. AIs can be classified as complete, partial, or mild based on the phenotypic presentation. The clinical findings include a female type of external genitalia, 46-XY karyotype, absence of Mullerian structures, presence of Wolffian structures to various degree, and normal to high testosterone and gonadotropin levels. We report this case as an interesting and rare syndrome. The patient is a 15-year-old phenotypic female who presented with primary amenorrhea and normal-appearing external genitalia. Orchidectomy was done after proper counselling and proper psychological support was given to her

A pharmacovigilance study of anti-depressant agents in psychiatric patients at a tertiary care teaching hospital

Background: Anti-depressant drugs have great benefit in treating a many psychiatric disorders, including schizophrenia and bipolar disorder, although all these drugs are associated with many potential adverse effects. In this study, the occurrence of adverse effects like weight gain, sleep disturbances, dry mouth were assessed and reported in drug naïve patients Anti-depressant drugs.Methods: It is a prospective observational study of patients attending Psychiatry department in NRI General Hospital of age 10 to 80 years who were prescribed with anti-depressant drugs. The study was conducted for a period of 8 months from June 2018 to February 2018.Results: Among 86 patients prescribed with antidepressants, the occurrence of adverse drug reactions due to antidepressants was 60.78% with Selective serotonin reuptake inhibitors being the most common class of drugs implicated for adverse drug reactions followed by 24.49% with Tricyclic antidepressants. A total of 51 adverse drug reactions were noted of which weight gain was most common, closely followed by sleep disturbances and drowsiness. Out of 52 adverse drug reactions assessed for causality, 88.2% of the adverse drug reactions cases were probable, while 11.7% were possible. According to Hartwig and Siegel’s Scale 84.3% of the cases are found to be mild, 15.68% moderate.Conclusions: The study allows knowing information about the occurrence and pattern of adverse drug reactions associated with Anti-depressant drugs in the population thus reducing its incidence and protecting the user population from available harm

Refinement of Mg alloys crystal structure via Nb-based heterogeneous substrates for improved performances

Copyright © 2018 The Author(s). Lightness and high specific strength make magnesium alloys ideal materials for the transportation industry, especially the automotive sector that is struggling to cope with the everyday more stringent regulations on emission of carbon dioxide. Wrought magnesium alloys are difficult to deform because of the few active slip systems characteristic of their hexagonal close-packed lattice. Consequently, most of the commercially available magnesium alloys are alloys based on the Mg-Al binary system used in casting processes. The improvement of the mechanical properties of these alloys cannot be achieved by means of grain refinement using Zr due to the formation of Zr aluminides. In this study we propose a novel chemical composition that can refine all types of Mg alloys as proved in the Al-containing AM50 Mg alloy. We demonstrate that Nb-B inoculation of Mg alloys promotes the formation of heterogeneously nucleated primary α-Mg grains leading to the reduction of the grain size and this is obtained over a wide range of cooling rates. We also show that the grain refinement achieved leads to the improvement of the properties of high pressure die cast Mg automotive components and has the potential to enhance the mechanical properties of cast Mg alloys.Engineering and Physical Sciences Research Counci

Dislocation Driven Chromium Precipitation in Fe-9Cr Binary Alloy: A Positron Lifetime Study

The influence of initial heat treatment on anomalous Cr precipitation within high temperature solubility region in Fe-9Cr alloy has been investigated using positron lifetime studies. Air-quenched samples with pre-existing dislocations exhibited a distinct annealing stage in positron lifetime between 800 and 1100 K corresponding to Cr-precipitation. During this stage, Transmission Electron Microscopy showed fine precipitates of average size 4 nm, dispersed throughout the sample and from EDS analysis they are found to be Cr-enriched. The existence of dislocations is found to be responsible for Cr precipitation.Comment: Revised version Submitted to Phys. Rev.

An AC susceptometer for the characterization of large, bulk superconducting samples

The main purpose of this work was to design, develop and construct a simple, low-cost AC susceptometer to measure large, bulk superconducting samples (up to 32 mm in diameter) in the temperature range 78-120 K. The design incorporates a double heating system that enables a high heating rate (25 K/hour) while maintaining a small temperature gradient (< 0.2 K) across the sample. The apparatus can be calibrated precisely using a copper coil connected in series with the primary coil. The system has been used successfully to measure the temperature dependence of the AC magnetic properties of entire RE-Ba-Cu-O [(RE)BCO] bulk superconducting domains. A typical AC susceptibility measurement run from 78 K to 95 K takes about 2 hours, with excellent temperature resolution (temperature step ~ 4 mK) around the critical temperature, in particular.Comment: 25 pages, 7 figures. Accepted for publication in Measurement Science and Technolog

Intratracheal Instillation of Cerium Oxide Nanoparticles Induces Hepatic Toxicity in Male Sprague-Dawley Rats

Background: Cerium oxide (CeO2) nanoparticles have been posited to have both beneficial and toxic effects on biological systems. Herein, we examine if a single intratracheal instillation of CeO2 nanoparticles is associated with systemic toxicity in male Sprague-Dawley rats. Methods and results: Compared with control animals, CeO2 nanoparticle exposure was associated with increased liver ceria levels, elevations in serum alanine transaminase levels, reduced albumin levels, a diminished sodium-potassium ratio, and decreased serum triglyceride levels (P \u3c 0.05). Consistent with these data, rats exposed to CeO2nanoparticles also exhibited reductions in liver weight (P \u3c 0.05) and dose-dependent hydropic degeneration, hepatocyte enlargement, sinusoidal dilatation, and accumulation of granular material. No histopathological alterations were observed in the kidney, spleen, and heart. Analysis of serum biomarkers suggested an elevation of acute phase reactants and markers of hepatocyte injury in the rats exposed to CeO2 nanoparticles. Conclusion: Taken together, these data suggest that intratracheal instillation of CeO2nanoparticles can result in liver damage