11,368 research outputs found

    Wind loads on Y plan shape tall building

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    An experimental study was carried out on the models of lsquoYrsquo plan shape tall building in an open circuit wind tunnel to investigate the wind loads generated on the building in isolated as well as interference condition. The base shear (Fx), overturning moment (My) and torsional moment (Mz) acting on the instrumented model were measured. For the isolated condition, the measurements were made for many wind incidence angles. For studying the interference effects, two similar building models were placed in side-by-side configuration and tandem configuration and the spacing between these models were varied. It is observed that the wind incidence angle greatly affects the wind induced loads on the lsquoYrsquo plan shaped building. Depending on the position of the interfering building, the interfence effects may either be beneficial or may have an adverse effect

    Photoinduced electron transfer in Langmuir-Blodgett films.

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    Photoinduced electron transfer from an excited donor molecule (oxacyanine) to an acceptor molecule (viologen) located at the same interface in monolayer assemblies has been studied by measuring steady state fluorescence quenching and the excited state decay of the donor molecule. Donor and acceptor molecules are incorporated in matrix monolayers of arachidic acid and methyl arachidate, with a molar ratio 9:1. It is seen that the electron transfer efficiency increases with increasing donor density (σd=0.005−0.425 nm−2). The fluorescence decay functions of the donor are described by assuming at least two fluorescent species and the results show that the contribution of long-lived species increases with increasing donor density. The average rate constant for the excited state electron transfer depends on the donor density and was found to be 2×108s−1 (σa = 0.025nm−2; σd = 0.005 nm−2). The results are rationalized in terms of energy delocalization via incoherent exciton hopping

    Implementation of FOAF, AIISO and DOAP ontologies for creating an academic community network using semantic frameworks

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    Web 2.0 delivers the information which is then displayed in human readable content, omitting the crucial information which can be drawn from the data by the applications. Web 3.0 or semantic web is an extension to the current web, with an ambition to determine the drawbacks of the current web. The semantic web has already proven its influence in several communities around the globe, such as social media, music industry, healthcare domain, online blogs or articles, etc.; Among the several tools and technologies, ontologies or vocabularies are the foundation pillar for the semantic web. In this paper, the developed system aims at improving the collaboration and academic relations among staff which is directly related to our education community by providing a better networking platform which lets the agents discuss their achievements, titles, domain interests, and various other activities. Results have been analyzed to show how new facts, information can be implied from the presented knowledge of several agents and help generate a relationship graph by utilizing various semantic tools. The system discussed in this paper processes all the information in a format which can be understood by both humans and the machines, to interpret the underlying meaning about it and provide effective results

    Coherent large-scale structures in high Reynolds number supersonic jets

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    The flow structure of a 50.8 mm (2 in) diameter jet operated at a full expanded Mach number of 1.37, with Reynolds numbers in the range 1.7 to 2.35 million, was examined for the first 20 jet diameters. To facilitate the study of the large scale structure, and determine any coherence, a discrete tone acoustic excitation method was used. Phase locked flow visualization as well as laser velocimeter quantitative measurements were made. The main conclusions derived from this study are: (1) large scale coherent like turbulence structures do exist in large Reynolds number supersonic jets, and they prevail even beyond the potential core; (2) the most preferential Strouhal number for these structures is in the vicinity of 0.4; and (3) quantitatively, the peak amplitudes of these structures are rather low, and are about 1% of the jet exit velocity. Finally, since a number of unique problems related to LV measurements in supersonic jets were encountered, a summary of these problems and lessons learned therefrom are also reported

    A study of the transmission characteristics of suppressor nozzles

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    The internal noise radiation characteristics for a single stream 12 lobe 24 tube suppressor nozzle, and for a dual stream 36 chute suppressor nozzle were investigated. An equivalent single round conical nozzle and an equivalent coannular nozzle system were also tested to provide a reference for the two suppressors. The technique utilized a high voltage spark discharge as a noise source within the test duct which permitted separation of the incident, reflected and transmitted signals in the time domain. These signals were then Fourier transformed to obtain the nozzle transmission coefficient and the power transfer function. These transmission parameters for the 12 lobe, 24 tube suppressor nozzle and the reference conical nozzle are presented as a function of jet Mach number, duct Mach number polar angle and temperature. Effects of simulated forward flight are also considered for this nozzle. For the dual stream, 36 chute suppressor, the transmission parameters are presented as a function of velocity ratios and temperature ratios. Possible data for the equivalent coaxial nozzle is also presented. Jet noise suppression by these nozzles is also discussed

    Asymptotically Optimal Approximation Algorithms for Coflow Scheduling

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    Many modern datacenter applications involve large-scale computations composed of multiple data flows that need to be completed over a shared set of distributed resources. Such a computation completes when all of its flows complete. A useful abstraction for modeling such scenarios is a {\em coflow}, which is a collection of flows (e.g., tasks, packets, data transmissions) that all share the same performance goal. In this paper, we present the first approximation algorithms for scheduling coflows over general network topologies with the objective of minimizing total weighted completion time. We consider two different models for coflows based on the nature of individual flows: circuits, and packets. We design constant-factor polynomial-time approximation algorithms for scheduling packet-based coflows with or without given flow paths, and circuit-based coflows with given flow paths. Furthermore, we give an O(log⁥n/log⁥log⁥n)O(\log n/\log \log n)-approximation polynomial time algorithm for scheduling circuit-based coflows where flow paths are not given (here nn is the number of network edges). We obtain our results by developing a general framework for coflow schedules, based on interval-indexed linear programs, which may extend to other coflow models and objective functions and may also yield improved approximation bounds for specific network scenarios. We also present an experimental evaluation of our approach for circuit-based coflows that show a performance improvement of at least 22% on average over competing heuristics.Comment: Fixed minor typo

    A New Receiver for a Digital Passband System with CPSK Modulation: The STTS-CPSK Receiver

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    671-677Telecommunications industry is expanding vastly with huge infrastructure requiring huge sums of money for investment1,2. Reliability of the system3,4, efficient utilization of resources1,2, and safety of the users and the environment are paramount towards providing high quality efficient telecom services at affordable prices1,2. This paper deals with an important scientific investigation for the development of the STTS-CPSK receiver for pass band applications5,6 . This is a new receiver being developed with the inspiration from the previously developed STTS-MF receiver for baseband applications. This is carried out considering transmission of p-q signals (p-q signals represent correlated digital signals) through AWGN channel. Performance-comparison studies of the conventional STS-CPSK receiver and the new STTS-CPSK receiver are carried out for a wide range of signal and system parameters 0.0 ≀ p,q ≀ 1.0 and-10 dB ≀ SNR ≀ 10 dB. Performance superiority of the STTS-CPSK receiver is established for 0.0 ≀ p,q ≀ 1.0, -2 dB ≀ SNR ≀ 10 dB, and illustrated. Thus, this work has important implications towards efficient utilization of bandwidth, and also in greening of communication technologies which is highly needed. The latter is because the performance-improvement, achieved in case of STTS-CPSK receiver, can be translated into an equivalent advantage of EMF-reduction appropriately

    Enhancing and Sustaining Pulse Production and Farmer Incomes in the TRFA Statess: Issues of Stray Animal Grazing and Value Chain Integration for Small and Marginal Farmers

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    Pulses are an integral component of a sustainable crop-production system, as these crops are capable of biological nitrogen fixation and have low water requirements and a high capacity to withstand changing weather conditions. Pulses are widely grown and consumed in India owing to their high nutritional value, especially as a source of protein. While India contributes 25 percent of the world’s pulse production, its domestic demand far exceeds the available supply. This has led to increasing pressure on prices, accessibility across different income strata, and the country importing pulses for domestic consumption
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