311 research outputs found

    Entrepreneurial Orientation and Resource Acquisition: An Environmental Dynamism Perspective

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    This study attempts to define the three constructs identified in the title and examine patterns of interaction among them. It begins by demonstrating that entrepreneurial orientation influences resource acquisition. It then puts forward a set of parameters to assess the degree to which factor identified as environmental dynamism affect an entrepreneurial orientation resource acquisition equation. The study finds that there are relationships between all three of the constructs, but in two propositions developed in the course of discussion it puts forward issues that may be clarified by future research, which from various angles could show how entrepreneurially oriented firms react differently from more established firms in terms of their acquisition of resources and interaction with environmental dynamism

    Service selection in service oriented architecture using probabilistic approach and asynchronous queues with interceptor validation

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    In service Oriented Architecture, many services are offered with similar functionality but with different service quality parameters. Thus the service selection using a deterministic approach causes conflicts and inefficient results. We use asynchronous queue to model the service inventory architecture avoiding unnecessary locking of resources and thus allowing a provision to consumers to get their required services without intervening and with temporally decoupled fashion. Actually this kind of service selection strategy is considered in regards with game theory to eliminate fluctuations of queue length. It offers a discrete random service which is equal to some request requested by consumers, it means service can be provided based on probability mass function as a substitute of deterministic decisions for selecting a proper service provider as of the consumers. Once the request is taken out from the queue, it is delivered to the interceptor that has validation and sanitization module. It thus reduces the peak queue length and reduces periodic fluctuations in the queue length

    Seismic Evaluation of the US41 Southbound Bridge over the Ohio River at Henderson, KY

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    This report presents the seismic evaluation of the US41 Southbound bridge over the Ohio River connecting Evansville, Indiana and Henderson, Kentucky. The main bridge is a four-span cantilever through-truss type. The approach bridge has 9 spans on the Evansville, IN side and 20 spans on the Henderson, side. Although this bridge has not yet been subjected to a moderate or major earthquake, it is situated within the influence of the New Madrid and Wabash Valley Seismic Zones. The seismic evaluation program consisted of field testing and seismic response analysis. The modal properties of the main bridge were determined through field testing, and were used to calibrate a three dimensional finite element model. The finite element model was then subjected to the acceleration time histories of the 50-year earthquake event. Stresses and displacements due to projected earthquakes are found to be very low. Analytical results indicate that the main bridge superstructure will survive the projected 50-year earthquake without any damage and no loss-of-span. However, all the supports on the piers of the main bridge require additional anchor bolts or seismic isolation bearings. The Kentucky and Indiana approach spans are analyzed using the response spectrum method with simplified single-degree-of-freedom models. Ten out of twelve supports having fixed bearings on both the approach spans require additional anchor bolts or seismic isolation bearings. At three out of twenty-five supports having expansion bearings, the existing rocker bearings need to be replaced with elastomeric bearings or cable restrainers need to be provided to avoid loss-of-span

    Seismic Evaluation of the US41 Northbound Bridge over the Ohio River at Henderson, KY

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    This report presents the seismic evaluation of the US41 Northbound bridge over the Ohio River connecting Evansville, Indiana and Henderson, Kentucky. The main bridge is a four-span cantilever through-truss type. The approach bridge has 8 spans on the Evansville, IN side and 35 spans on the Henderson, KY side. Although this bridge has not yet been subjected to a moderate or major earthquake, it is situated within the influence of the New Madrid and Wabash Valley Seismic Zones. The seismic evaluation program consisted of field testing and seismic response analysis. The modal properties of the main bridge were determined through field testing, and were used to calibrate a three dimensional finite element model. The finite element model was then subjected to time histories of the 50-year earthquake event. Stresses and displacements obtained were found to be within the acceptable limits. Analytical results indicate that the superstructure of the main bridge will survive the projected 50-year earthquake without any damage and no loss-of-span. However, all supports on the piers of the main bridge require additional anchor bolts or seismic isolation bearings. The approach spans were analyzed using response spectrum method with simplified single-degree-of-freedom models. Thirteen out of forty-two supports having fixed bearings on both the Kentucky and Indiana approach spans require additional anchor bolts at the fixed bearings or seismic isolation bearings

    In-orbit Performance of UVIT on ASTROSAT

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    We present the in-orbit performance and the first results from the ultra-violet Imaging telescope (UVIT) on ASTROSAT. UVIT consists of two identical 38cm coaligned telescopes, one for the FUV channel (130-180nm) and the other for the NUV (200-300nm) and VIS (320-550nm) channels, with a field of view of 28 arcminarcmin. The FUV and the NUV detectors are operated in the high gain photon counting mode whereas the VIS detector is operated in the low gain integration mode. The FUV and NUV channels have filters and gratings, whereas the VIS channel has filters. The ASTROSAT was launched on 28th September 2015. The performance verification of UVIT was carried out after the opening of the UVIT doors on 30th November 2015, till the end of March 2016 within the allotted time of 50 days for calibration. All the on-board systems were found to be working satisfactorily. During the PV phase, the UVIT observed several calibration sources to characterise the instrument and a few objects to demonstrate the capability of the UVIT. The resolution of the UVIT was found to be about 1.4 - 1.7 arcsecarcsec in the FUV and NUV. The sensitivity in various filters were calibrated using standard stars (white dwarfs), to estimate the zero-point magnitudes as well as the flux conversion factor. The gratings were also calibrated to estimate their resolution as well as effective area. The sensitivity of the filters were found to be reduced up to 15\% with respect to the ground calibrations. The sensitivity variation is monitored on a monthly basis. UVIT is all set to roll out science results with its imaging capability with good resolution and large field of view, capability to sample the UV spectral region using different filters and capability to perform variability studies in the UV.Comment: 10 pages, To appear in SPIE conference proceedings, SPIE conference paper, 201

    High-Spatial-Resolution OH PLIF Visualization in a Cavity-Stabilized Ethylene-Air Turbulent Flame

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    High-spatial-resolution OH planar laser-induced fluorescence was measured for a premixed ethylene-air turbulent flame in an electrically-heated Mach 2 continuous-flow facility (University of Virginia Supersonic Combustion Facility, Configuration E.) The facility comprised a Mach 2 nozzle, an isolator with flush-wall fuel injectors, a combustor with optical access, and an extender. The flame was anchored at a cavity flameholder with a backward-facing step of height 9 mm. The temperature-insensitive Q1(8) transition of OH was excited using laser light of wavelength 283.55 nm. A spatial filter was used to create a laser sheet approximately 25 microns thick based on full-width at half maximum (FWHM). Extension tubes increased the magnification of an intensified camera system, achieving in-plane resolution of 40 microns based on a 50% modulation transfer function (MTF). The facility was tested with total temperature 1200 K, total pressure 300 kPa, local fuel/air equivalence ratios of approximately 0.4, and local Mach number of approximately 0.73 in the combustor. A test case with reduced total temperature and another with reduced equivalence ratio were also tested. PLIF images were acquired along a streamwise plane bisecting the cavity flameholder, from the backward facing step to 120 mm downstream of the step. The smallest observed features in the flow had width of approximately 110 microns. Flame surface density was calculated for OH PLIF images

    High-Resolution OH and CH2O Visualization in a Premixed Cavity-Anchored Ethylene-Air Flame in a M = 0.6 Flowfield

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    OH and CH2O were imaged in a premixed, cavity-anchored, ethylene-air turbulent flame using a high resolution planar laser-induced fluorescence (PLIF) system. The electrically-heated, continuous flow facility (UVa Supersonic Combustion Facility, Configuration E) consisted of a Mach 2 nozzle, an isolator with fuel injectors, a test section with a cavity flame holder and optical access, and an extender. Standard test conditions comprised total temperature 1200 K, total pressure 300 kPa, local equivalence ratio near 0.4, and local Mach number near 0.6. OH PLIF data was also collected for a case with reduced total temperature and another with reduced equivalence ratio. OH and CH2O were excited in separate experiments with light sheets at 283.55 nm and 352.48 nm, respectively. A light sheet of approximate thickness 25 ?m illuminated the stream-wise midplane. This plane was imaged for 120 mm downstream of the backward-facing step. The intensified camera system imaged OH with magnification 1.97, a square 6.67 mm field of view, and in-plane resolution of 39 ?m. The smallest observed OH structures observed were approximately 100 ?m wide. The CH2O PLIF image signal was much weaker; the smallest observed structures were approximately 200 ?m wide. Composite fluorescence images were computed for the observed area
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