2,427 research outputs found

    Analytical studies of new airfoils for wind turbines

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    Computer studies were conducted to analyze the potential gains associated with utilizing new airfoils for large wind turbine rotor blades. Attempts to include 3-dimensional stalling effects were inconclusive. It is recommended that blade pressure measurements be made to clarify the nature of blade stalling. It is also recommended that new laminar flow airfoils be used as rotor blade sections

    Feasibility study of aileron and spoiler control systems for large horizontal axis wind turbines

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    The feasibility of using aileron or spoiler controls as alternates to pitch control for large horizontal axis wind turbines was studied. The NASA Mod-0 100 kw machine was used as the basis for the study. Specific performance studies were conducted for 20% chord ailerons over the outboard 30% span, and for 10% chord spoilers over the same portion of the span. Both control systems utilized control deflections up to 60 deg. Results of the study show that either ailerons or spoilers can provide the control necessary to limit turbine power in high wind conditions. The aileron system, as designed, provides overspeed protection at hurricane wind speeds, low wind speed starting torque of 778 N-m (574 ft. lb) at 3.6 m/sec, and a 1.3 to 1.5% increase in annual energy compared to a fixed pitch rotor. The aileron control system preliminary design study includes aileron loads analysis and the design of a failsafe flyweight actuator for overspeed protection in the event of a hydraulic system failure

    Student Affairs Professionals’ Perceptions of Campus Incivility

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    The purpose of this study was to gather data regarding student affairs professionals’ perceptions of student incivility and which acts of incivility are most often observed. Results from 409 participants suggested that student affairs professionals perceive that “very uncivil” acts are observed less often whereas acts that are perceived to be neither civil nor uncivil are witnessed more frequently. In addition, findings indicated that student affairs professionals are seeing an increase in uncivil acts related to social media and technology, and the manner in which students are using social media to vent frustrations with campus staff and their peers. Finally, recommendations for practice and further research are provided

    Inquiry as Practice: The Pathway to Redesigning an Educational Leadership Doctoral Research Seminar Series

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    As faculty of an educational leadership doctoral program (EdD) aligned with the Carnegie Project on the Education Doctorate (CPED) principles, we acknowledge the importance of inquiry to develop scholarly practitioners. Applying the tenet of Inquiry as Practice, our EdD faculty critically examined the doctoral curriculum to explore ways to effectively prepare our doctoral students to learn and apply research methodology meaningfully. This essay details how the review of our research curriculum led to a pedagogical and curriculum redesign of our research seminar series. This revised research seminar series culminates in a course offered every fall/spring semester in the final two years of the program and intentionally has different faculty members teaching each course. We have utilized a backward design to create the themes/content of these seminar courses to better prepare students for their dissertation research

    The METCRAX II Field Experiment: A Study of Downslope Windstorm-Type Flows in Arizona\u2019s Meteor Crater

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    The second Meteor Crater Experiment (METCRAX II) was conducted in October 2013 at Arizona\u2019s Meteor Crater. The experiment was designed to investigate nighttime downslope windstorm 12type flows that form regularly above the inner southwest sidewall of the 1.2-km diameter crater as a southwesterly mesoscale katabatic flow cascades over the crater rim. The objective of METCRAX II is to determine the causes of these strong, intermittent, and turbulent inflows that bring warm-air intrusions into the southwest part of the crater. This article provides an overview of the scientific goals of the experiment; summarizes the measurements, the crater topography, and the synoptic meteorology of the study period; and presents initial analysis results

    The highly conserved methionine of subunit I of the heme-copper oxidases is not at the heme-copper dinuclear center: Mutagenesis of M110 in subunit I of cytochrome bo3-type ubiquinol oxidase from Escherichia coli

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    AbstractA common feature within the heme-copper oxidase superfamily is the dinuclear heme-copper center. Analysis via extended X-ray absorption fine structure (EXAFS) has led to the proposal that sulfur may be bound to CUB, a component of the dinuclear center, and a highly conserved methionine (M110 in the E. coli oxidase) in subunit I has been proposed as the ligand. Recent models of subunit I, however, suggest that this residue is unlikely to be near CUB, but is predicted to be near the low spin heme component of the heme-copper oxidases. In this paper, the role of M110 is examined by spectroscopic analyses of site-directed mutants of the bo3-type oxidase from Escherichia coli. The results show that M110 is a non-essential residue and suggest that it is probably not near the heme-copper dinuclear center

    Advancing functional connectivity research from association to causation

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    Cognition and behavior emerge from brain network interactions, such that investigating causal interactions should be central to the study of brain function. Approaches that characterize statistical associations among neural time series-functional connectivity (FC) methods-are likely a good starting point for estimating brain network interactions. Yet only a subset of FC methods ('effective connectivity') is explicitly designed to infer causal interactions from statistical associations. Here we incorporate best practices from diverse areas of FC research to illustrate how FC methods can be refined to improve inferences about neural mechanisms, with properties of causal neural interactions as a common ontology to facilitate cumulative progress across FC approaches. We further demonstrate how the most common FC measures (correlation and coherence) reduce the set of likely causal models, facilitating causal inferences despite major limitations. Alternative FC measures are suggested to immediately start improving causal inferences beyond these common FC measures
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