12,669 research outputs found

    Combinators and bisimulation proofs for restartable systems

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    Geomagnetic storm effects on GPS based navigation

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    The energetic events on the sun, solar wind and subsequent effects on the Earth's geomagnetic field and upper atmosphere (ionosphere) comprise space weather. Modern navigation systems that use radio-wave signals, reflecting from or propagating through the ionosphere as a means of determining range or distance, are vulnerable to a variety of effects that can degrade the performance of the navigational systems. In particular, the Global Positioning System (GPS) that uses a constellation of earth orbiting satellites are affected due to the space weather phenomena. <br><br> Studies made during two successive geomagnetic storms that occurred during the period from 8 to 12 November 2004, have clearly revealed the adverse affects on the GPS range delay as inferred from the Total Electron Content (TEC) measurements made from a chain of seven dual frequency GPS receivers installed in the Indian sector. Significant increases in TEC at the Equatorial Ionization anomaly crest region are observed, resulting in increased range delay during the periods of the storm activity. Further, the storm time rapid changes occurring in TEC resulted in a number of phase slips in the GPS signal compared to those on quiet days. These phase slips often result in the loss of lock of the GPS receivers, similar to those that occur during strong(>10 dB) L-band scintillation events, adversely affecting the GPS based navigation

    Production and characterization of used cooking oil as an alternative fuel: optimization by response surface methodology

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    The application of biodiesel in internal combustion engines are increasing at a faster rate, due to the fact that biodiesel posses more oxygen content (Approximately 12 %), which helps in the complete combustion of the fuel. On the other hand the production cost of the biodiesel is high compared to mineral diesel fuel. This may be due to the availability of raw oil and its high initial cost. To minimize the high initial cost of the biodiesel used cooking oil is one of the best solutions. In this paper an attempt was made to analyze the fatty acid compositions and other characteristics of used cooking oil. Optimization techniques like response surface methodology (RSM) was successfully used for better yield estimation with the help of advanced software Design Expert. The optimum values of the variables were: oil to methanol ratio (1:8.37), catalyst concentration (0.74 Wt%), reaction temperature (47.950 °C) and reaction time (54.58 min) at 250 rpm. The predicted response value at these optimum values was 96.15 %. To confirm these optimum values, experimentations were conducted based on the optimum values and achieve the yield of 96 %. This shows that the yield of used cooking oil methyl ester is very near to the optimum value with an error of 0.15 % which may be accepted. This showed that the model correctly explains the influence of the process variables on the production of FAME from used cooking oil (UCOME). And from the gas chromatography results there is equal distribution of saturated and unsaturated fatty acids. 14 % oxygen can be acclaimed in UCOME by elemental analysis. Unsaturated level of fatty acids are observed

    Remote surface inspection system

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    This paper reports on an on-going research and development effort in remote surface inspection of space platforms such as the Space Station Freedom (SSF). It describes the space environment and identifies the types of damage for which to search. This paper provides an overview of the Remote Surface Inspection System that was developed to conduct proof-of-concept demonstrations and to perform experiments in a laboratory environment. Specifically, the paper describes three technology areas: (1) manipulator control for sensor placement; (2) automated non-contact inspection to detect and classify flaws; and (3) an operator interface to command the system interactively and receive raw or processed sensor data. Initial findings for the automated and human visual inspection tests are reported

    Visualisation of an entangled channel spin-1 system

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    Co-variance matrix formalism gives powerful entanglement criteria for continuous as well as finite dimensional systems. We use this formalism to study a mixed channel spin-1 system which is well known in nuclear reactions. A spin-j state can be visualized as being made up of 2j spinors which are represented by a constellation of 2j points on a Bloch sphere using Majorana construction. We extend this formalism to visualize an entangled mixed spin-1 system.Comment: 4 pages,4 figure

    Novel phytosynthesis of nanoparticles using Indigeneous Australian Plants

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    Nanoparticles are considered to be the building blocks of nanotechnology. Biosynthesis of nanoparticles using plant material is an exciting and relatively new developing research area in nanobiotechnology. In the present study, Eucalyptus leaves were collected from Olive pink botanical garden, Alice Springs, Australia and were used to synthesize silver nanoparticles. Cubical structured and well monodispersed silver nanoparticles were formed with an average size of 50nm. The formed silver nanoparticles are found to have promising applications in medicine as good antimicrobial agents. To the best of our knowledge this is the first report on exploiting indigeneous Australian plant sources for the synthesis of metallic nanoparticles

    Schwannoma arising from hypoglossal nerve in the submandibular triangle: a case report

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    Hypoglossal schwannomas usually develop in the intracranial portion of the brain. The incidence of hypoglossal schwannomas of the submandibular region is extremely rare. Here we report a case of schwannoma arising from the extracranial hypoglossal nerve in the left submandibular region

    The many ways of returning to the refrain in Telugu song

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    A refrain (abbreviated R) is a line in a song repeated after each verse, and often used as the\ua0song’s name. Returns to R are usually high points both melodically and lyrically. E.g., a verse\ua0ending "I feel upon my lips again" makes a smooth lead-in (abbreviated L) to the refrain R =\ua0"A taste of honey" (Scott/Marlow, 1962). We notate this "(I feel upon my lips again) A taste of\ua0honey", and call such patterns (lead-in)refrains or (L)R’s. The song goes R … LR … LR, where\ua0L could change verse to verse. In our examples, R and (L)R are often both full sentences. More\ua0interesting L’s are often phrases, clauses or rather than interjections. A word-prefix L can\ua0transform R.Our main contribution is to point out that (L)R patterns are a striking feature of Telugu (TEL)\ua0song, remarkably various and profuse in both old and new songs, yet little remarked in the\ua0literature as far as we are aware. We give examples from the 15th c. to the 21st. In transcription, a\ua0colon marks long vowels, and M, nasalized ones. Retroflexion is shown by capitalization, and\ua0aspiration by h, also a consonant by itself. Glosses are given, some also /morpheme-wise/.Kannada (KAN) and Tamil (TAM) share features with TEL that help make L(R)’s: fairly free word\ua0order, agglutinative particles, and adjectives and relative clauses preceding the noun. We give\ua0only lone KAN and TAM examples, but expect to find more when we search. Hindi (HIN) shares\ua0fewer features with TEL; perhaps therefore, we have so far looked but found few (L)R s in HIN

    ANTIOXIDANT AND ANTIULCER POTENTIAL OF ETHANOLIC EXTRACT OF BARK OF MYRICA ESCULENTA IN PYLORIC LIGATION ULCER MODEL

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    Objective: To evaluate the antiulcer and antioxidant potential of ethanolic extract of bark of Myrica esculenta in pyloric ligated ulcer model in albino rats.Methods: The rats were subjected to pyloric ligation ulcer model and the ethanolic extract of bark of Myrica esculenta were compared with the induced and standard drug Ranitidine. The activity of antioxidant parameters was analysed in the homogenate of stomachs.Results: The levels of gastric volume, total acidity, free acidity, lipid peroxidation and glutathione (GSH) were reduced significantly and antioxidant, parameters like catalase, nitrite and myeloperoxidase (MPO) were increased significantly in the ethanloic extract of bark of Myrica esculenta. Conclusion: The present study revealed that the ethanolic extract of bark of Myrica esculenta improved the anti ulcer and antioxidant potential. Â
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