10,266 research outputs found

    Towards an Intelligent Workflow Designer based on the Reuse of Workflow Patterns

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    In order to perform process-aware information systems we need sophisticated methods and concepts for designing and modeling processes. Recently, research on workflow patterns has emerged in order to increase the reuse of recurring workflow structures. However, current workflow modeling tools do not provide functionalities that enable users to define, query, and reuse workflow patterns properly. In this paper we gather a suite for both process modeling and normalization based on workflow patterns reuse. This suite must be used in the extension of some workflow design tool. The suite comprises components for the design of processes from both legacy systems and process modeling

    Navier-Stokes analysis and experimental data comparison of compressible flow within ducts

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    Many aircraft employ ducts with centerline curvature or changing cross-sectional shape to join the engine with inlet and exhaust components. S-ducts convey air to the engine compressor from the intake and often decelerate the flow to achieve an acceptable Mach number at the engine compressor by increasing the cross-sectional area downstream. Circular-to-rectangular transition ducts are used on aircraft with rectangular exhaust nozzles to connect the engine and nozzle. To achieve maximum engine performance, the ducts should minimize flow total pressure loss and total pressure distortion at the duct exit. Changes in the curvature of the duct centerline or the duct cross-sectional shape give rise to streamline curvature which causes cross stream pressure gradients. Secondary flows can be caused by deflection of the transverse vorticity component of the boundary layer. This vortex tilting results in counter-rotating vortices. Additionally, the adverse streamwise pressure gradient caused by increasing cross-sectional area can lead to flow separation. Vortex pairs have been observed in the exit planes of both duct types. These vortices are due to secondary flows induced by pressure gradients resulting from streamline curvature. Regions of low total pressure are produced when the vortices convect boundary layer fluid into the main flow. The purpose of the present study is to predict the measured flow field in a diffusing S-duct and a circular-to-rectangular transition duct with a full Navier-Stokes computer program, PARC3D, and to compare the numerical predictions with new detailed experimental measurements. The work was undertaken to extend previous studies and to provide additional CFD validation data needed to help model flows with strong secondary flow and boundary layer separation. The S-duct computation extends the study of Smith et al, and Harloff et al, which concluded that the computation might be improved by using a finer grid and more advanced turbulence models. The present study compares results for both the Baldwin-Lomas and k-epsilon turbulence models and is conducted with a refined grid. For the transition duct, two inlet conditions were considered, the first with straight flow and the second with swirling flow. The first case permits examination of the effects of the geometric transition on the flow field, while the second case includes the rotational flow effect characteristic of a gas turbine engine

    Characterization of porous, dexamethasone-releasing polyurethane coatings for glucose sensors.

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    Commercially available implantable needle-type glucose sensors for diabetes management are robust analytically but can be unreliable clinically primarily due to tissue-sensor interactions. Here, we present the physical, drug release and bioactivity characterization of tubular, porous dexamethasone (Dex)-releasing polyurethane coatings designed to attenuate local inflammation at the tissue-sensor interface. Porous polyurethane coatings were produced by the salt-leaching/gas-foaming method. Scanning electron microscopy and micro-computed tomography (micro-CT) showed controlled porosity and coating thickness. In vitro drug release from coatings monitored over 2 weeks presented an initial fast release followed by a slower release. Total release from coatings was highly dependent on initial drug loading amount. Functional in vitro testing of glucose sensors deployed with porous coatings against glucose standards demonstrated that highly porous coatings minimally affected signal strength and response rate. Bioactivity of the released drug was determined by monitoring Dex-mediated, dose-dependent apoptosis of human peripheral blood derived monocytes in culture. Acute animal studies were used to determine the appropriate Dex payload for the implanted porous coatings. Pilot short-term animal studies showed that Dex released from porous coatings implanted in rat subcutis attenuated the initial inflammatory response to sensor implantation. These results suggest that deploying sensors with the porous, Dex-releasing coatings is a promising strategy to improve glucose sensor performance

    A search for X-ray emission from rich clusters, extended halos around clusters, and superclusters

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    The all-sky data base acquired with the HEAO A-2 experiment was searched for X-ray emission on a variety of metagalactic size scales which were either predicted or previously detected. Results in the 0.2-60 keV energy range are presented. The optically richest clusters, including those from which a microwave decrement were observed, appear to be relatively underluminous in X-rays. Observations of Abell 576 show its luminosity to be less than earlier estimates, and moreover less than the luminosity predicted from its microwave decrement, unless the intracluster gas is a factor of approximately 10 hotter than in typical clusters. Near SC0627 there are two X-ray sources, and the identification of the dominant source with SCO627 is probably incorrect. New spectral observations of Abell 401 and 2147, possible superclusters, reveal that they have typical cluster spectra with iron line emission

    Colloidal hydrodynamic coupling in concentric optical vortices

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    Optical vortex traps created from helical modes of light can drive fluid-borne colloidal particles in circular trajectories. Concentric circulating rings of particles formed by coaxial optical vortices form a microscopic Couette cell, in which the amount of hydrodynamic drag experienced by the spheres depends on the relative sense of the rings' circulation. Tracking the particles' motions makes possible measurements of the hydrodynamic coupling between the circular particle trains and addresses recently proposed hydrodynamic instabilities for collective colloidal motions on optical vortices.Comment: 7 pages, 2 figures, submitted to Europhysics Letter

    X-Ray Scattering at FeCo(001) Surfaces and the Crossover between Ordinary and Normal Transitions

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    In a recent experiment by Krimmel et al. [PRL 78, 3880 (1997)], the critical behavior of FeCo near a (001) surface was studied by x-ray scattering. Here the experimental data are reanalyzed, taking into account recent theoretical results on order-parameter profiles in the crossover regime between ordinary and normal transitions. Excellent agreement between theoretical expectations and the experimental results is found.Comment: 9 pages, Latex, 1 PostScript figure, to be published in Phys.Rev.

    ІНЖЕНЕРИ У СКЛАДІ ДЕПУТАЦІЇ ВІД УКРАЇНСЬКИХ ГУБЕРНІЙ У ДЕРЖАВНІЙ ДУМІ РОСІЙСЬКОЇ ІМПЕРІЇ (1906-1917 рр.)

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    В останні два-три десятиліття історики проявляють постійний інтерес до народу як носія влади і до форм участі його в державотворенні. Досвід прожи-тих років трактується як надбання нації, відтак вивчення комплексу проблем, пов’язаних з участю депутатів від українських губерній Російської імперії в ін-ституції парламентського типу – Державній думі – є актуальною проблемою. Об’єктом цього дослідження є суспільно-політичні процеси в українських губе-рніях Російської імперії, власне у Наддніпрянській Україні, на початку ХХ ст., предметом – депутати Державної думи перших чотирьох скликань, обрані від українських губерній і міст, конкретно – інженери за фахом. Мета дослідження – розгляд соціопрофесійної групи технічної інтеліген-ції в загальному складі думської депутації. Цьому складу притаманна в цілому дуже строката структура у своїх соціальних, політичних, освітніх, професійних, конфесійних та інших характеристиках. Тому, окрім іншого, необхідно визна-чити місце інженерів у цьому середовищі й подати конкретну інформацію про них. При цьому власне думська діяльність їх наразі не розглядається, як і пода-льша їх доля після 1917 року. Завдання щодо конкретної інформації випливає зі стану історіографічної розробки проблеми. Думська проблематика є дуже популярною у Російській Федерації; сплеск інтересу до неї посилився у зв'язку з широким відзначенням столітнього ювілею Думи у РФ у 2006 році [13]. В Україні досі не існує якогось центру вивчення зазначених проблем, проте на рівні дисертаційних досліджень та статей їх розробка все ж здійснюється, причому географія таких досліджень досить широка, від Харкова до Кам’янця-Подільського [9; 5]. Висвітлення ж теми у заявленому формулюванні досі нам невідоме

    A study of the ultrasonic treatment effect on microstructure and mechanical properties of commercial purity titanium

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    This work presents a study of the ultrasonic treatment effect on microstructure and mechanical properties of ac-received and recrystallized commercial purity titanium specimens by means XRD, EBSD and TEM. It was demonstrated that the dislocation density growth and the twins with special boundaries [sigma]7b and [sigma]11b increase within the surface grains during ultrasonic treatment depend on initial structural state of the titanium specimens. The relationship between the structural parametrs change and the surface layer microhardness value of the titanium specimens subjected to ultrasonic treatment was shown. It was found that differences in the hardened surface layer depth and the surface microhardness of ac-received and recrystallized titanium specimens result in the same yield and ultimate tensile strength increment during ultrasonic treatment

    Refactoring Process Models in Large Process Repositories.

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    With the increasing adoption of process-aware information systems (PAIS), large process model repositories have emerged. Over time respective models have to be re-aligned to the real-world business processes through customization or adaptation. This bears the risk that model redundancies are introduced and complexity is increased. If no continuous investment is made in keeping models simple, changes are becoming increasingly costly and error-prone. Though refactoring techniques are widely used in software engineering to address related problems, this does not yet constitute state-of-the art in business process management. Process designers either have to refactor process models by hand or cannot apply respective techniques at all. This paper proposes a set of behaviour-preserving techniques for refactoring large process repositories. This enables process designers to eectively deal with model complexity by making process models better understandable and easier to maintain
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