100 research outputs found
Studies on Fabrication of Ag/HgBaCaCuO/CdSe Heterostructures by Pulse-Electrodeposition Route
Metal/superconductor/semiconductor (Ag/HgBaCaCuO/CdSe) heterostructures have
been successfully fabricated using pulse-electrodeposition technique. The
electrochemical parameters are optimized and diffusion free growth of CdSe onto
Ag/HgBaCaCuO was obtained by employing under-potential deposition and by
studying nucleation and growth mechanism during deposition. The
heterostructures are characterized by X-ray diffraction (XRD), full-width at
half-maximum (FWHM), scanning electron microscopy (SEM) studies and low
temperature four probe electrical resistivity measurements. After the
deposition of CdSe the critical transition temperature of HgBaCaCuO films was
found be increased from 115 K with Jc = 1.7 x 103 A/cm2 to 117.2 K with Jc =
1.91 x 103 A/cm2. When the heterostructure was irradiated with red He-Ne laser
(2 mW), the Tc was further enhanced to 120.3 K with Jc = 3.7 x 103 A/cm2. This
increase in superconducting parameters of HgBaCaCuO in Ag/ HgBaCaCuO/CdSe
heterostructure has been explained at length in this paper.
Keywords. Electrodeposition; Hg-based cuprate; semiconductor;
heterostructures; electrical properties.
PACS Nos 81.15.Pq; 74.72.Gr; 78.40.Fy; 84.37; 73.40 *E-mail:
[email protected], [email protected]: 22 Pages, 12 Figures. Submitted to Semiconductor Science and
Technology. Submitted to Semiconductor Science and Technolog
The Mitochondrial Genome of Baylisascaris procyonis
BACKGROUND: Baylisascaris procyonis (Nematoda: Ascaridida), an intestinal nematode of raccoons, is emerging as an important helminthic zoonosis due to serious or fatal larval migrans in animals and humans. Despite its significant veterinary and public health impact, the epidemiology, molecular ecology and population genetics of this parasite remain largely unexplored. Mitochondrial (mt) genomes can provide a foundation for investigations in these areas and assist in the diagnosis and control of B. procyonis. In this study, the first complete mt genome sequence of B. procyonis was determined using a polymerase chain reaction (PCR)-based primer-walking strategy. METHODOLOGY/PRINCIPAL FINDINGS: The circular mt genome (14781 bp) of B. procyonis contained 12 protein-coding, 22 transfer RNA and 2 ribosomal RNA genes congruent with other chromadorean nematodes. Interestingly, the B. procyonis mtDNA featured an extremely long AT-rich region (1375 bp) and a high number of intergenic spacers (17), making it unique compared with other secernentean nematodes characterized to date. Additionally, the entire genome displayed notable levels of AT skew and GC skew. Based on pairwise comparisons and sliding window analysis of mt genes among the available 11 Ascaridida mtDNAs, new primer pairs were designed to amplify specific short fragments of the genes cytb (548 bp fragment) and rrnL (200 bp fragment) in the B. procyonis mtDNA, and tested as possible alternatives to existing mt molecular beacons for Ascaridida. Finally, phylogenetic analysis of mtDNAs provided novel estimates of the interrelationships of Baylisasaris and Ascaridida. CONCLUSIONS/SIGNIFICANCE: The complete mt genome sequence of B. procyonis sequenced here should contribute to molecular diagnostic methods, epidemiological investigations and ecological studies of B. procyonis and other related ascaridoids. The information will be important in refining the phylogenetic relationships within the order Ascaridida and enriching the resource of markers for systematic, population genetic and evolutionary biological studies of parasitic nematodes of socio-economic importance
Preparation of Nickel Modified Carbon Fibre Electrodes and their Application for Methanol Oxidation
Nickel modified carbon fibre electrodes were prepared by electrochemical oxidation and partial reduction of a graphite fibre electrode with a slow linear potential sweep in 97% H2SO4 solution followed by impregnation & ion exchange with Ni +2 species. The cyclic voltammetry of the modified electrode in an alkaline medium showed electrocatalytic activity towards methanol oxidation which is consistent with the behaviour of a polycrystalline nickel electrode in the same media. The electrode fabricated through the ion exchange with 0.1 M Ni solution provided the most significant response for solutions with lower methanol concentrations up to 0.5 M methanol while at higher concentrations of methanol, a poisoning effect was observed resulting in lower performanc
Distribution and Prevalence of \u3ci\u3eEchinococcus multilocularis\u3c/i\u3e in Wild Predators in Nebraska, Kansas, and Wyoming
To further determine the distribution and prevalence of Echinococcus multilocularis in the central United States, 245 wild canids (125 red foxes, 120 coyotes) and 33 bobcats were collected from Nebraska, Kansas, and Wyoming and examined for this parasite. Animals examined included 11 red foxes from the western panhandle of Nebraska; 5 red foxes and 30 coyotes from southern Nebraska; 56 red foxes and 1 coyote from northeastern Nebraska; 20 red foxes, 63 coyotes, and 13 bobcats from northern Kansas; 2 red foxes, 26 coyotes, and 20 bobcats from southern Kansas; and 31 red foxes from eastcentral Wyoming. Of these, 27 of 72 (37.5%) red foxes from Nebraska were positive, including 2 of 11 (18.2%) from the western panhandle and 25 of 56 (44.6%) from the northeastern part of the state. Mean intensity of infection was 282 worms (range, 1–5,150). New distribution records were established for E. multilocularis in western Nebraska as well as for several northeastern counties. These findings support previous estimates that the southernmost front of the parasite’s range extends along the southern border of Wyoming, eastward through central Nebraska and central Illinois into Indiana and Ohio
Fault Detection and Diagnosis In Hall–Héroult Cells Based on Individual Anode Current Measurements Using Dynamic Kernel PCA
Individual anode current signals in aluminum reduction cells provide localized cell conditions in the vicinity of each anode, which contain more information than the conventionally measured cell voltage and line current. One common use of this measurement is to identify process faults that can cause significant changes in the anode current signals. While this method is simple and direct, it ignores the interactions between anode currents and other important process variables. This paper presents an approach that applies multivariate statistical analysis techniques to individual anode currents and other process operating data, for the detection and diagnosis of local process abnormalities in aluminum reduction cells. Specifically, since the Hall–Héroult process is time-varying with its process variables dynamically and nonlinearly correlated, dynamic kernel principal component analysis with moving windows is used. The cell is discretized into a number of subsystems, with each subsystem representing one anode and cell conditions in its vicinity. The fault associated with each subsystem is identified based on multivariate statistical control charts. The results show that the proposed approach is able to not only effectively pinpoint the problematic areas in the cell, but also assess the effect of the fault on different parts of the cell
Estimation of spatial alumina concentration in an aluminum reduction cell using a multilevel state observer
In the Hall-Héroult process, spatial variations in alumina concentration are very difficult to measure and impossible to estimate from the conventionally monitored line amperage and cell voltage. This article presents an approach to estimate in real time the alumina concentration distribution in an aluminum reduction cell based on individual anode current measurements. One of the key difficulties is that the localized mass transfer rates are unknown. To overcome this issue, a multilevel state observer is developed based on the robust extended Kalman filter. The approach utilizes a dynamic model of a reduction cell that is discretized subsequently level by level, where the estimated variables at each level are used to estimate more detailed alumina concentration spatial distribution at the next level. The proposed approach is validated in an experimental study using an industrial cell. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2806–2818, 2017
Detection of Local Cell Conditions Based on Individual Anodecurrent Measurements
© 2016 by The Minerals, Metals & Materials Society. All rights reserved.The application of individual anode current measurements in the Hall-Héroult cells has been investigated to aid cell monitoring, in addition to the conventional use of cell voltage measurements. Its advantages are significant, especially in high amperage cells, where information from the voltage signal is heavily diluted. One common use of individual anode current measurements is to identify process faults that can cause a significant change in the local current flow paths between anode busbar and the metal pad. While this detection is simple and direct, there are other consequential changes in cell conditions that impact the current distribution in the vicinity of a problem anode. This paper presents a Moving Window Kernel PCA-based method to extract spatial information from the individual anode current signals by incorporating other known process variables
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