1,603 research outputs found

    PONDER - A Real time software backend for pulsar and IPS observations at the Ooty Radio Telescope

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    This paper describes a new real-time versatile backend, the Pulsar Ooty Radio Telescope New Digital Efficient Receiver (PONDER), which has been designed to operate along with the legacy analog system of the Ooty Radio Telescope (ORT). PONDER makes use of the current state of the art computing hardware, a Graphical Processing Unit (GPU) and sufficiently large disk storage to support high time resolution real-time data of pulsar observations, obtained by coherent dedispersion over a bandpass of 16 MHz. Four different modes for pulsar observations are implemented in PONDER to provide standard reduced data products, such as time-stamped integrated profiles and dedispersed time series, allowing faster avenues to scientific results for a variety of pulsar studies. Additionally, PONDER also supports general modes of interplanetary scintillation (IPS) measurements and very long baseline interferometry data recording. The IPS mode yields a single polarisation correlated time series of solar wind scintillation over a bandwidth of about four times larger (16 MHz) than that of the legacy system as well as its fluctuation spectrum with high temporal and frequency resolutions. The key point is that all the above modes operate in real time. This paper presents the design aspects of PONDER and outlines the design methodology for future similar backends. It also explains the principal operations of PONDER, illustrates its capabilities for a variety of pulsar and IPS observations and demonstrates its usefulness for a variety of astrophysical studies using the high sensitivity of the ORT.Comment: 25 pages, 14 figures, Accepted by Experimental Astronom

    Planetary Bistatic Radar

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    Planetary radar observations offer the potential for probing the properties of characteristics of solid bodies throughout the inner solar system and at least as far as the orbit of Saturn. In addition to the direct scientific value, precise orbital determinations can be obtained from planetary radar observations, which are in turn valuable for mission planning or spacecraft navigation and planetary defense. The next-generation Very Large Array would not have to be equipped with a transmitter to be an important asset in the world's planetary radar infrastructure. Bistatic radar, in which one antenna transmits (e.g., Arecibo or Goldstone) and another receives, are used commonly today, with the Green Bank Telescope (GBT) serving as a receiver. The improved sensitivity of the ngVLA relative to the GBT would improve the signal-to-noise ratios on many targets and increase the accessible volume specifically for asteroids. Goldstone-ngVLA bistatic observations would have the potential of rivaling the sensitivity of Arecibo, but with much wider sky access.Comment: 11 pages, 2 figures, To be published in the ASP Monograph Series, "Science with a Next-Generation VLA", ed. E. J. Murphy (ASP, San Francisco, CA

    Case studies to enhance online student evaluation: Bond University – Surveying students online to improve learning and teaching

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    One of the most sensible ways of improving learning and teaching is to ask the students for feedback. At the end of each teaching period (i.e. semester or term) all universities and many schools survey their students. Usually these surveys are managed online. Questions ask for student perceptions about teaching, assessment and workload. The survey administrators report four common problems

    Finger Ridge Count Correlations Among Four Tribes of Andhra Pradesh, India

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    The present paper reports the distribution of finger ridge count correlations among four tribal populations from Andhra Pradesh, India viz., Dulia, Kotia, Manne Dora and Manzai Mali, and examines the intra and inter population variation. Higher correlations are recorded in left hands compared to right hands, but they are not significant. The homologous fingers exhibit a stronger correlation. In all the tribes, the correlations between right hand fingers are relatively higher among women when compared to men. Regarding inter population variation Dulia men differ significantly from the men of Manne Dora and the Manzai Mali tribes, and Kotia women also differ from the women of the Manne Dora significantly. The average correlation coefficient of the present populations is similar to other Indian populations reported earlier but lower than African and European populations

    Multilevel SVM and AI based Transformer Fault Diagnosis using the DGA Data

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    The Dissolved Gas Analysis (DGA) is utilized as a test for the detection of incipient prob-lems in transformers, and condition monitoring of transformers using software-based diagnosis tools has become crucial. This research uses dissolved gas analysis as an intel-ligent fault classification of a transformer. The Multilayer SVM technique is used to de-termine the classification of faults and the name of the gas. The learned classifier in the multilayer SVM is trained with the training samples and can classify the state as normal or fault state, which contains six fault categories. In this paper, polynomial and Gaussi-an functions are utilized to assess the effectiveness of SVM diagnosis. The results demonstrate that the combination ratios and graphical representation technique is more suitable as a gas signature, and that the SVM with the Gaussian function outperforms the other kernel functions in diagnosis accuracy

    Operative management of tibial plateau fractures: an assessment of functional and radiological outcomes with Rasmusssens scoring system

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    Background: Fractures of the proximal tibia involve a major weight bearing joint and are intra-articular injuries which frequently result in functional impairment. They require an accurate reduction of the articular surface with stable internal fixation. If these fractures are not managed appropriately, they often result in high rates of morbidity in the form of knee stiffness and arthritis. This study was done to assess the functional and radiological outcomes following various surgical modalities and to compare them with other studies as available in literature.Methods: 30 patients with tibial plateau fractures treated by various surgical modalities at Saveetha Medical College and Hospital were studied from January 2013 to February 2015 and were followed up for a minimum period of 6 months. Functional and radiological outcomes were assessed by the Rasmussens scoring system.Results: All 30 patients fulfilling the inclusion criteria were thoroughly evaluated and were taken up for surgery with various modalities of fixation which included cannulated cancellous screws, T and L buttress plates and locking compression plates. Articular surface elevation with bone grafting was done in depressed fractures. Early knee mobilization was started and strict non-weight bearing walking was advocated. We had a 90% acceptable functional result which was comparable with other studies.Conclusions: In our study, we conclude that accurate reduction of the articular surface with stable internal fixation and early mobilization with bone grafting in depressed fractures with protracted weight bearing till fracture union gives good functional results. Also radiological values often do not often correlate well with functional outcomes.

    Catalytic activity of nickel ferrite nanoparticles in synthesis of 4-aryl benzelidene-2- ((5-fluoro-1H-indol-1-yl)methyl)oxazol-5(4H)-one and its evalute the biological activity

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    ABSTRACT. Seven 4-arylbenzelidene-2-((5-fluoro-1H-indol-1-yl)methyl)oxazol-5(4H)-one derivatives were synthesized by the condensation of 2-(2-(5-fluoro-1H-indol-1-yl) acetoamide) acetic acid, substituted aromatic aldehydes with acetic anhydride and sodium acetate in the presence of MgO/Al2O3 under reflux using nickel ferrite nanoparticles. Seven of the compounds are new derivatives. 2-(2-(5-fluoro-1H-indol-1-yl)acetoamide) acetic acid was obtained from 2-(5-fluoro-1H-indol-1-yl)acetyl chloride with lysine in the presence of NaOH and HCl in the ice cold solution. 2-(5-fluoro-1H-indol-1-yl)acetyl chloride can be prepared from 5-fluoro indole with chloroacetyl chloride in triethylamine and dichloromethane. The structures of the compounds were evaluated based on 1H-NMR, 13C-NMR and LC-MS and by elemental analysis. These compounds were screened by anti-oxidant as well as anti-microbial activity.               KEY WORDS: 2-(5-Fluoro-1H-indol-1-yl)acetyl chloride, 2-(2-(5-Fluoro-1H-indol-1-yl)acetoamide) acetic acid, 4-Aryl Benzelidene-2-((5-fluoro-1H-indol-1-yl)methyl)oxazol-5(4H)-one, Anti-oxidant, Anti-microbial activity, Nickel ferrite Bull. Chem. Soc. Ethiop. 2019, 33(3), 517-526.  DOI: https://dx.doi.org/10.4314/bcse.v33i3.1
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