10,563 research outputs found

    Measurement of point velocities in turbulent liquid flow

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    Turbulent water flow velocity distribution using hot-wire anemometer and photographic technique

    A case study of process facility optimization using discrete event simulation and genetic algorithm

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    Optimization problems such as resource allocation, job-shop scheduling, equipment utilization and process scheduling occur in a broad range of processing industries. This paper presents modeling, simulation and optimization of a port facility such that effective operational management is obtained. A GA base approach has been integrated with the port system model to optimize its operation. A case study of bulk material port handling systems is considered

    Effectiveness of educator-oriented content courses

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    The idea of teaching science strikes fear into the hearts and minds of many elementary teachers; however, as a core piece of the overall curriculum, they cannot escape teaching science. The courses taken at the university and the professional development classes taken on the job play a critical role in helping educators feel comfortable teaching science. Such courses also impact how the content is taught by introducing the best practices used in science teaching. As a Basic Science Minor in the College of Education at the University of Northern Iowa, I have taken many science content courses and several courses that educate about the different methods of teaching elementary school science. Because of such classes I feel very prepared to teach science in the classroom, but not all teachers feel the same level of preparedness or comfort related to teaching science. Noticing this brought about the overall question What is the effectiveness of educator-oriented science classes? and the related survey question How many science content courses did you take in college? Which were geared toward teachers? An educator-oriented science content course covers various science disciplines and are designed specifically for elementary education majors. They present science and learning science via pedagogical approaches considered good practice for teaching science. I realized not all in-service educators took an educator-oriented science class at their university, but they have all had opportunities to take professional development courses about science. This led to the second survey question, How many professional development classes have you taken in each content area: life science, physical science, and earth science? If the educator had taken an educator-oriented science class in college, attended a professional development class about science, or done both would it make a difference in their level of comfort for teaching science? Would it affect the way an educator taught science in the classroom

    Canine Spondylitis

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    An eight-year-old yellow Labrador was referred to the Iowa State University Veterinary Clinic on September 24, 1961, with a history of posterior asthenia and incoordination. Chronic nephritis had been diagnosed a month previously and since that time the dog had become progressively weaker and wobbled considerably. Occasionally, he would lie and howl

    Population inversion in optically pumped asymmetric quantum well terahertz lasers

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    Intersubband carrier lifetimes and population ratios are calculated for three- and four-level optically pumped terahertz laser structures. Laser operation is based on intersubband transitions between the conduction band states of asymmetric GaAs-Ga(1 – x)Al(x)As quantum wells. It is shown that the carrier lifetimes in three-level systems fulfill the necessary conditions for stimulated emission only at temperatures below 200 K. The addition of a fourth level, however, enables fast depopulation of the lower laser level by resonant longitudinal optical phonon emission and thus offers potential for room temperature laser operation. © 1997 American Institute of Physics

    DSM-V: Modifying the postpartum-onset specifier to include hypomania

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    By failing to include it under the rubric of the postpartum-onset specifier, Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV-TR has ignored the clinical reality that childbirth is a potent trigger of hypomania. Given the serious and occasionally tragic consequences of misdiagnosis of bipolar II depression as unipolar depression in the postpartum period, it is argued that DSM-V should consider modifying the postpartum-onset specifier to include episodes of hypomania. © 2010 The Author(s)

    The Minimum Wiener Connector

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    The Wiener index of a graph is the sum of all pairwise shortest-path distances between its vertices. In this paper we study the novel problem of finding a minimum Wiener connector: given a connected graph G=(V,E)G=(V,E) and a set QVQ\subseteq V of query vertices, find a subgraph of GG that connects all query vertices and has minimum Wiener index. We show that The Minimum Wiener Connector admits a polynomial-time (albeit impractical) exact algorithm for the special case where the number of query vertices is bounded. We show that in general the problem is NP-hard, and has no PTAS unless P=NP\mathbf{P} = \mathbf{NP}. Our main contribution is a constant-factor approximation algorithm running in time O~(QE)\widetilde{O}(|Q||E|). A thorough experimentation on a large variety of real-world graphs confirms that our method returns smaller and denser solutions than other methods, and does so by adding to the query set QQ a small number of important vertices (i.e., vertices with high centrality).Comment: Published in Proceedings of the 2015 ACM SIGMOD International Conference on Management of Dat
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